US 3554325 A
Description (OCR text may contain errors)
United States Patent Conwell Savage New York, N.Y.
 inventor ] Appl. No. 817,789  Filed Apr. 21, 1969  Patented Jan. 12, 1971 Wes inghouse Electric Corporation Pittsburgh, Pa. a corporation of Pa.
 Assignee  MOTOR CONTROL MECHANISM 18 Claims, 15 Drawing Figs.
 U.S.CI 187/29, 318/324  Int. Cl 1366b 1/28 187/29;
 Field of Search 3/1969 Krauer et al.
Primary Examiner-Gris L. Rader Assistant Examiner-W. E. Duncanson, Jr.
Attorneys-A. T. Stratton, C. L. Freedman and R. V.
Westerhoff ABSTRACT: A mechanism for controlling the movement of an elevator car has a helical frame which is threadedly advanced in synchronism with the car. The helix passes under a control head which is mounted on an arm pivoted about the axis of the helix. The control head is rotated through a limited arc by the arm in a direction opposite to the direction of rotation of the helix as the car begins to move. Displacement of the arm from the neutral position generates a speed reference signal and establishes the advance car position relative to floor stops mounted on the helical frame at points proportional to the location of the landings. When the car is to be stopped, a pawl on the control head is dropped and the car is slowed down as the floor stop engages the pawl and returns the arm to the neutral position. Various switches associated with other control functions such as door opening are operated at selected points in the travel of the control head and arm.
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INVENTOR Conwell Sovoge ATTORNEY PATENTEU JAN 1 2 i9?! SHEET 3 BF 8 PATENTED JAN 1 2 l9?! SHEET M F 8 FIG] FiGH.
I PATENTED JAN 1 2 1971 SHEET 8 [IF 8 mmm III 1 1711/1 MOTOR CONTROL MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is applicable to motor speed control systems and is particularly oplicable to motor speed control apparatus for transportation. systems such as elevators where it is desired to bring the car to a smooth accurate stop at a precise point to be determined while the vehicle is in motion.
2. Description of the Prior Art Precise speed control is essential in transportation systems such as elevators for the comfort and safety of the passengers as well as for the accuracy of the landings. The problem is further compounded in elevator systems where the desired stopping point may be changed while the vehicle is in motion. A major problem is determining at what point slowdown should be initiated so that the car will come to a smooth stop level with the landing reasonably quickly.
Devices known as floor selectors which are in effect a form of a scale model of the elevator system which moves in synchronism with the car have been used for many years in the elevator field. One such floor selector disclosed in U.S. Pat. No. 2,002,986 teaches the distribution of inductive zones spaced in accordance with the spacing of the landings along a pair of conductors helically wound on the surface of a rotating drum. As the drum is rotated in synchronism with the movement of the car, a crosshead carrying a number of coils is threadedly advanced along an axis parallel to the axis of the helix. One of the coils represents the actual position of the car relative to the landings. When this coil passes one of the inductive zones on the rotating drum a current is induced in the coil indicating that the car is adjacent that floor. Coils displaced on the crosshead ahead of and behind the car will have a current induced in them as the car approaches a landing from above and below respectively. As the car approaches a floor at which it is to stop therefore a current is induced in this slowdown coil and a deceleration process is initiated. Slowdown in this system is accomplished by a number of successive stepwise reductions in the speed of the car.
Other systems utilize complicated electromechanical devices which control slowdown of the car as a function of relative movement between a pair of carriages. In such a system one carriage moves in synchronism with the car, while the second carriage advances out ahead of the car a distance proportional to the distance required for the car to stop. When the advance carriage reaches the point on the floor selector proportional to the point in the hatchway at-which the car is to be brought to a stop, its movement is stopped and as the synchronous carriage approaches the now stationary advance carriage, slowdown is initiated by switches activated by the relative movement of the carriages. Examples of such systems are the systems disclosed in U.S. Pat. Nos. 2,271,998 and 2,874,806. In the former patent helical floor segments which are rotated about the axis of the helix cooperate with switches which are advanced along the axis of the helix in synchronism with the movement of the car to effect precise leveling. However, as in the case of the U.S. Pat. No. 2,002,986 mentioned above, the helix does not advance axially. In both the U.S. Pat. Nos. 2,271,998, and 2,874,806 a separate advance motor is required to operate the advance carriage. I
tion is limited to an amount corresponding to the predeteb mined maximum control signal desired. When it is desired that the movable object be brought to a stop, the movable element is coupled for movement in the reverse direction in synchronism with the movement of the movable object to return the movable element to the neutral position.
lt is contemplated that the mechanism which is the subject of this invention be used in a feedback type control system wherein the control signal is continuously compared with an actual speed signal to produce an error signal which controls energization of the driving means. The mechanism could be used however, in an open loop speed control system also.
Although the mechanism could be utilized in numerous speed control systems and especially in speed control systems for transportation apparatus, it will be described as applied to an elevator system to which it is particularly adaptable. 1n the preferred embodiment of the invention, a helical frame is rotated and axially advanced in synchronism with the movement of the car. Lugs secured to the helix at points proportional to the location of the landings protmde from the surface of the helix. A control head supported by an L-shaped arm which is pivoted around the axis of the helix carries a number of switches which are successively actuated by the floor stops as the helix threadedly advances on a screw having the same pitch as that of the helix.
The helix is driven by a synchronous gear fastened to one end of the helix which advances along an elongated pinion gear on a rotating shaft whose axis is parallel to the axis of the helix. The arm supporting the control head is rigidly attached to the screw through the axis of the helix. At one end of the threaded shaft is a clutch plate rigidly connected to the shaft. An advance gear coaxially mounted on the threaded shaft for independent rotation is driven in the opposite direction to that of the helix through a spur gear which also meshes with the elongated pinion gear on the rotatingshaft.
A clutch mechanism when actuated forces the advance gear against the clutch plate thereby causing the threaded shaft and the control head mounted thereto to rotate in the direction opposite to the direction of rotation of the helix. A transducer connected to the opposite end of the threaded shaft produces a control signal proportional to the displacement of the control head from the neutral position. Since the control head moves in the direction opposite to the direction of rotation of the helix, the control head moves with respect to the floor stops at a much higher rate. than the car actually moves with respect to the landings. The difference in the relative displacement between the control head andthe floor stops as compared to the actual displacement of the car from a landing is the distance'over' which the car has been accelerated. This same distance will be required to bring the car to a stop. The
position of the control head with respect to the floor stops I therefore represents the advance position of the car or the The most widely used method of controlling acceleration in elevator systems is to generate a speed control signal as a function of time beginning with the application of the start signal. On the other hand, the system described in U.S. Pat. No. 2,271,998 mentioned above accelerates the elevator car as a stepwise function of the distance the car has traveled.
SUMMARY OF THE INVENTION point at which the car could be brought to a stopif deceleration was initiated at that instant. When the control headhas advanced to the position at which the transducer generate's the maximum control signal desired, the head activates a switch which disengages the clutch and the control head remains in the advance position. During this stage the car maintains a" constant speed which is determined by the output of the transducer.
When it is desired to bring the elevator car to a-stop, a sole synchronism with the movement of the car towards the neutral position. As the control head moves toward theneutral posi tion, the output of the transducer is reduced and therefore' 'the car slows down. The car will be opposite the landingwhen the floor stop has driven the control head to the neutral position." Means are provided at each end of travel'of the helix cor responding to the car approaching the top or bottom landing for engaging and returning the control head to theneutra'l position should the pawls fail to drop due to a malfunction in" the system.
The control mechanism which is the subject of this invention could be mounted on the car and driven by a stationary rope in the hatchway looped around the driving drum; however, preferably the mechanism is mounted in the penthouse and driven by a tape connected to the car.
The transducer which produces the output signal of the mechanism may take varying forms and may produce either an electrical or mechan.cal output. Basically, a cam is connected to the end of the threaded shaft to which is connected the control head. Displacement of the control head from the neutral position results in proportional displacement of the cam. The cam may be used to vary the reluctance of a coil and thereby produce an electrical output, or it can, through the utilization of cam followers, adjust the setting of a potentiometer which would also produce an electrical output. In still another configuration it could be utilized through cam followers to mechanically adjust the position of the control element on a drag magnet speed regulator such as that disclosed in U.S. Pat. No. 2,874,806 mentioned above.
As an additional feature of the invention, movement of the control head can be utilized to manipulate cam operated switches to perform such functions as door preopening as the car approaches a landing at which it is to stop.
It is therefore a first object of the invention to provide an improved motor speed control mechanism.
It is another object of the invention to provide an improved motor speed control mechanism wherein speed is controlled as a continuous function of the displacement of the movable object from the starting point during acceleration and from the stopping point during deceleration.
It is yet another object of the invention to provide an improved speed control mechanism for an elevator system which does not require a separate advance motor.
It is still another object of the invention to provide a speed control mechanism of the type described in the previous object in which the advance position of the car is established by having the movable elements of the mechanism move in opposite directions relative to each other.
It is a further object of the invention to provide an improved speed control mechanism which is simple, durable, reliable and inexpensive.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an elevator system embodying the invention;
FIG. 2 is a sectional view in side elevation with parts cut away of the speed control mechanism;
FIG. 3 is an enlarged view in plan of a section of the helical frame shown in FIG. 2;
FIG. 3A is an enlarged view in plan of a floor stop.
FIG. 4 is a sectional end view with parts broken away and parts missing taken along IV-IV of the mechanism shown in FIG. 2;
FIG. 5 is an enlarged side elevation view with some parts broken away of the control head and control arm;
FIG. 6 is a front elevation view of the control head;
FIG. 7 is an enlarged perspective view of part of the control head shown in FIGS. 5 and 6;
FIG. 8 is a detailed vertical cross-sectional view of a portion of the mechanism taken along the line VIII-VIII in FIG. 4;
FIG. 9 is a vertical end view with some parts in section and some parts cut away taken generally along the line IX-IX in FIG. 2;
FIG. 10 is a schematic wiring diagram for some of the switches utilized in the invention;
FIG. 11 is a mechanical diagram illustrating the relative movement of the main operating components of the mechanism;
FIG. 12 is a vertical sectional view taken along the same line as FIG. 9 for a modification of that portion of the mechanism;
FIG. 13 is also a vertical sectional view taken along the same line as FIG. 9 for yet another modification of that portion of the mechanism;
FIG. 14 is a side view in elevation with parts missing of the modification illustrated in FIG. 13; and
FIG. 14 is a side view in elevation with parts missing of the modification illustrated in FIG. 13; and
FIG. 15 is a side view taken along line XVXV of a portion of the modification shown in FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Although the mechanism could be utilized with other types of speed control systems, it will be described as applied to an elevator system. FIG. 1 illustrates a simplified elevator system embodying the invention wherein a car I is mounted for movement relative to a structure 2 having four landings. The car is supported by a rope 3 which is 'reeved over a traction sheave 5 on the shaft of a direct current motor M. A counterweight 7 is connected to the other end of the rope 3. A drive tape 9 connected to the top and bottom of the car to form a closed loop is reeved over the sprocket 11 of the control mechanism 15 located in the penthouse and over a pulley 13 located at the bottom of the hatchway. Alternatively, the control mechanism 15 could be located on the car and driven by a stationary rope in the hatchway looped around the drive drum 1 1.
The control mechanism 15 which is the subject of this invention is controlled by and supplies information to a supervisory control system 17. Although almost any supervisory system could be easily adapted for use with the control mechanism which is the subject of this invention, a suitable system is the one described in the application of Andrew F. Kirsch, Ser. No. 606,231, filed Dec. 30, I966 and assigned to the same assignee.
The speed reference signal generated by the control mechanism 15 serves as a pattern signal for a speed regulator 19. Although any speed regulator which varies the speed of the motor in accordance with a pattern signal could be utilized, it will be assumed that the solid state type of regulator disclosed in the application of William R. Caputo and the application of William R. Caputo and William M. Ostrander which are assigned to the same assignee and identified as application Nos. 837,442 and 845,604,respectively is utilized. In that system, the pattern signal is compared with a signal generated by a tachometer which is representative of the actual speed of the motor. The resultant signal is amplified by a silicon controlled rectifier amplifier and serves as the excitation signal for a direct current generator 21. The current produced by the generator controls the motor M. This motor generator combination is the familiar Ward-Leonard direct current drive system. Positive feedback from the generator to the speed regulator increases the sensitivity of the regulator while negative acceleration feedback from the motor minimizes hunting.
Referring to FIGS. 2 and 9, it can be seen that the drive tape 9 has rectangular evenly spaced holes lfl distributed along its centerline. It can beseen'from the sectional view in FIG. 2 that the drive sprocket 11 is actually composed of two parallel plates 25 spaced axially approximately the width of the tape by spacers 29. Rivets 31 through the plates and the spacer give the sprocket rigidity. Beveled rollers 33 evenly distributed around the circumference of the sprocket the same distance apart as the holes 10 in the drive tape are free to rotate about their axes. These rollers protrude radially beyond the circum-' ference of the plates 25 so that they may engage the holes 10 in the tape 9 and thereby assure positive drive.
As can be seen from FIG. 2, the sprocket 11 is mounted on a drive shaft 35 which is joumaled in its forward end by a bearing 37 mounted on the supporting structure having a base 39 and a front wall 41. The drive shaft 35 is joumaled at its remote end in a bearing 43 mounted on the rear bracket 45. Gear teeth extending along a substantial length of the drive shaft 35 form an elongated pinion gear 36.
A helical carriage 47 is mounted on a threaded shaft 49 extending through the axes of the helical carriage. The threaded shaft is joumaled in an oilite bearing 51 mounted in the front support 41 and is journaled at the other end by a ball bearing 53 mounted on the rear bracket 45. A synchronous gear 55 concentrically mounted on one end of the helical carriage 47 engages the pinion gear 36 on the drive shaft. When the drive shaft is rotated therefore, the synchronous gear and the helical carriage 47 are rotated in a direction opposite to the direction of rotation of the drive shaft 35. A spur gear 57 (see FIG. 4) engages the pinion gear 36 and an advance gear 59 identical to the synchronous gear 55 mounted for free rotation about the threaded shaft 49. The advance gear therefore rotates in the same direction as the drive shaft 35 or in other words in an opposite direction to the direction of rotation of the synchronous gear 55.
A clutch plate 61 rigidly connected to the threaded shaft 49 normally rotates clear of the advance gear 59. A control arm 63 rigidly connected to the forward end of the threaded shaft 49 carries a control head 65. A clutch mechanism 67 to be described in detail below, is operative under certain conditions to force the advance gear 59 axially into engagement with the clutch plate 61 to thereby effect rotation of the threaded shaft 49.
Connected to the forward end of the threaded shaft 49 is a transducer 69. Referring to FIG. 9 which illustrates the preferred embodiment of the invention, the transducer 69 is composed of a cam 71 having an arcuate cam surface 72 rigidly connected to the threaded shaft 49. A cam follower designated generally by the reference character 73 has an arm 75 which is pivoted on a stub shaft 77 connected to the front support 41 (see FIG. 2). A spacer 78 displaces the cam follower from the support structure 41. A spring 76 biases a roller 74 connected to the center of the arm against the cam 71. A segment gear 79 at the free end of the arm 75 engages a spur gear 81 on a potentiometer 83. Rotation of the cam 71 by the threaded shaft 49 varies the angular displacement of the cam follower 73 in accordance with the variation in the radius of the cam surface in contact with the roller 74. The effective resistance of the potentiometer 83 is therefore varied in accordance with the angular position of the threaded shaft 49. The potentiometer is pivotally mounted on a pin 84 and is urged into contact with the segment gear 79 by a spring 86. A spacer 85 maintains clearance between the control arm 63 and the cam follower 73 as can be seen in FIG. 2.
By referring to FIGS. 2, 3 and 4, it can be seen that the helical carriage referred to generally by the reference character 47, is built around a hollow cylindrical nut 87 which engages the threaded shaft 49. Therefore, when the synchronous gear 55 is rotated by the drive shaft 35, the entire helical carriage 47 is moved axially with respect to the threaded shaft 49. The helical surface is composed of 270 segments shown in detail by the general reference character 89 in FIG. 3. Each segment comprises an annular rib 91 having tongues 93a, b and c protruding radially inward at the 45, l35 and 225 points around the inner surface of the rib 91. The tongues 93 have holes 95. Mounting arms 99 proceeding radially outward from the supporting rib and then circumferentially parallel to the supporting rib leave annular grooves 97 with radial openings at the ends of the mounting arms.
The tongues 93 are each twisted about their radial centerline the same number of degrees, for instance 3, in the same direction so that when the segment is oriented so that the planes of the twisted tongues are parallel, the periphery of the segment assumes a pitch with respect to the central axes of the segment. For instance, if each of the tongues of the segment shown in FIG. 3 were twisted counterclockwise about their radial centerline and the segment was then oriented so that all these tongues were parallel to the plane of view, the end of the support rib 91a would be closer to the viewer than the end 91b. If another identical segment were then oriented so that its edge 91b abutted the edge 91a of the segment shown in FIG. 3. the helix would continue out towards the viewer from the plane of FIG. 3. The tongue 93c of the second segment would then fall midway in the are between the tongues 93a and 930 of the segment shown in FIG. 3. The hole in the tongue 93b of the second segment will then line up with the hole 95 in' the tongue 930 of the segment shown in FIG. 3 and likewise the hole 93a of the second segment would line up with the hole 95 in the tongue 93b of FIG. 3. As will be seen below, the periphery of the helical frame thus formed represents on a reduced scale the length of the hatchway in which the elevator car is running. Therefore as many segments as are necessary to obtain the proper length of the helical path can be stacked up in this manner.
As can be seen from FIG. 2, four rods 101 connected to the synchronous gear 55 and quadrangularly spaced parallel to the axis of the cylindrical nut 87 pass through the holes 95 of the segments. Spacers 103 serve to maintain the individual segments in position and an end plate 105 is placed over the end of the stack. Nuts 107 hold the assembly together.
Bolted to the helical frame at points corresponding to the positions of the landings are floor stops 109 shown in detail in FIG. 3A. The floor stops are arcuate shaped pieces of metal having a cam surface on the outer periphery and three holes 110 along the inner radius. By providing three holes it is assured that the floor stop can be bolted to the helical frame by two bolts at any point desired. As can be seen best from FIG. 2, the floor stops have a double bend so that the cam surface is offset from the centerline of the helix. The floor stops for the odd number floors are fastened on the right side of the helix as seen in FIG. 2 and are identified by the reference character 109A. The floor stops for the even number floors are fastened on the other side of the helix and are identified by the reference character 109B. The floor stops 109A therefore trace a helical path known as the A lane while the floor stops 109B define the B lane. This purpose of this configuration is discussed below in connection with the notching switches mounted on the control head.
As was mentioned previously, the aft end of the threaded shaft 49 is journaled in the ball bearing 53 mounted in the rear support bracket 45. Axial movement of the threaded shaft 49 is restrained by the lock nut 54. It was also previously mentioned that the advance gear 59 rotates freely on the threaded shaft 49 except when urged into engagement with the clutch plate 61. Referring to FIGS. 2, 4 and 8 it can be seen that the clutch mechanism 67 includes clutch coils 111 and 113, and a clutch armature 115 pivoted around a pair of pivot rods 117 and prevented from dropping out too far by a stop screw 119. An operating pin 121 which protrudes into an axial bore in the threaded shaft 49 is seated in a thrust bearing 123 mounted on the clutch armature 115. An operating key 125 of a length somewhat longer than the diameter of the threadedshaft 49 is free to move axially in a longitudinal slot 127 in the threaded shaft 49 which communicates with the axial bore in which the operating pin 121 is inserted. The length of the operating pin 121 is such that it does not exert a force on the operating key when the armature coils are deactivated. Ho'wever,-it is long enough so that when energization is provided to the armature coils and the armature is attracted to the clutch coils. the thrust bearing 123 forces the operating pin 121 against the operating key 125 which in turn forces theadvan'ce gear 59 into engagement with the lip 62 on the clutch plate 61. Since the clutch plate 61 is rigidly connected to the threaded shaft 49, the shaft will rotate in the same direction as the advance gear 59. The threaded shaft 49 will carry with it the control arm 63 carrying the control head 65 and the cam 71. Since whenever the advance gear 59 is being rotated by the drive shaft, the synchronous gear is simultaneously being driven by the drive shaft in the opposite direction, the control head 65 will rotate in a direction opposite to the rotation of the helical carriage and therefore it will advance relative to any point on the helical path at twice the rate that the helical carriage moves relative to the control head when the clutch is disengaged.
Referring to FIGS. and 6 for detailed side and front views respectively of the control head, it can be seen that the control head is suspended from a horizontal end portion of the control arm 63. A metal plate 129 is secured to the control arm 63 by four screws 131. Two rear posts 133 are fastened vertically beneath the plate 129 at the two aft corners of the plate 129 by bolts 135. Forwaro posts 137 are suspended by bolts 139 from the two front corners of the plate 129. Two pawling coils, the left-hand coil 141 and a right-hand coil 143 as viewed in FIG. 6 are also suspended beneath the plate 129 by screws 145. A left-hand armature 147 and a right-hand armature 149 are pivoted for movement below the left-hand and right-hand coils respectively. Reference to the detailed perspective view of the left-hand armature assembly shown in FIG. 7 will be helpful in understanding this portion of the control head mechanism. The right-hand armature assembly is identical except it is in reverse.
The left-hand armature 147 has an extended portion which is bent downward to form a broadened pawl 151. Fastened along the lower left-hand edge of the armature 147 is a pivot member 155. A shaft 157 passes through the pivot piece 155 and the rearward and forward posts 133 and 137, respectively. A retaining ring 159 anchors the aft end of the shaft 157. The washers 161 are placed on the shaft between the pivot 155 and the forward'and rear posts. The forward end of the shaft 157 is received in a horizontal slot 163 in the forward post 137. An angle 165 secured to the post by a bolt 167 confines the shaft 157 to the slot. A spring 169 is connected to the shaft 157 and a stud 171 which is secured to the center of a rod 173 which is fastened to the forward post by nuts 175. A similar spring 169 is fastened to the pivot shaft 157 for the right-hand armature and also to the stud 171. These springs bias the shafts 157 towards the bottom of their respective slots. This arrangement acts as a shock absorber to cushion the jolt when the pawl is engaged by the floor selector as will be seen later.
Referring again to FIG. 7 it will be seen that bolts 177 secure spring arm 179 to the pivot piece 155. A bolt 181 protruding outwardly from the forward post 137 passes through a hole 180 on the upper projection of the spring arm. A coil spring concentrically mounted on the bolt 181 outside of the upper projection of the spring arm is restrained by a cup washer 185 and nuts 187. A spring 183 therefore biases the spring arm and consequently the armature 147 and paw] 151 into the position shown in FIG. 6. However, energization of the pawling coil 141 will attract the armature 147 thereby rotating it in a counterclockwise direction around the shaft 157 against the force exerted by the spring 183. On the other hand, it will be seen by referring to FIG. 4 that when the pawl 151 is engaged by a floor stop 109, the force exerted on the armature assembly will tend to rotate the armature assembly in a clockwise direction for the left-hand armature and therefore the head will be moved in synchronism with the floor stop on the helical carriage.
Referring again to FIGS. 5 and .6, it can be seen that a horizontal bracket 189 is secured to the back of the forward posts 137 by screws and lock washers 191. Secured to the bracket 189 by screws 199, are three double push switches 193, 195 and 197. The switches are arranged on the bracket 189 in a common arc with its axis at the center of the threaded shaft 49. Each of the switches is comprised of two independent switches having a plunger biased to an extended position wherein the circuit is completed through the switch. When the plunger is depressed the circuit is interrupted. For instance, the switch 193 has a switch with a plunger 2018 and a second switch directly behind the first switch as viewed in FIG. 6 with the plunger identified by the reference character 201A. Similarly the switch 195 has a B switch with the plunger 203B closer to the viewer and a second switch 203A directly behind it. The switch 197 likewise has an A switch and a B switch, however, the A switch with plunger 205A is closer to the viewer as seen in FIG. 6.
Switches 193 and 197 are notching switches which cooperate with the floor stops 109 mounted on the helical carriage to indicate to the supervisory system the position of the car in the shaft. Floor selectors are devices which generate an indication of the position of the car in the shaft. In the notching type floor selector, the selector notches in discrete steps from one floor indication to the next upon receiving a signal that the car has passed a predetermined point in the hatchway. Alternate lane notching wherein the selector receives an advancing signal on one bus when the car advances to odd numbered floors and receives the advance signal on a second bus when the car advances to an even number floor have been commonly used for many years. The two lanes are obtained by bolting the floor stops for odd numbered floors on one side of the helical carriage and the stops for the even numbered floors on the other side of the helical carriage as shown in FIG. 2 and discussed above. For instance, as the helical carriage rotates under the control head, the plunger 2018 will be depressed by floor stops 1098 but will be unactivated by the floor stops 109A. Notice however, that the plunger 205A will also be energized by the floor stops 1098 and will be uneffected by the floor stops 109A. On the other hand, the plunger 201A will be activated by the floor stops 109A but not 1098. It can be appreciated then that with the helical carriage advancing in the counterclockwise direction as viewed in FIG. 4 that as a 1098 floor stop passes under the control head, it will depress the plungers 2018, 20313 and 205A successively.
Although other floor selectors could be utilized it will be assumed for the purpose of illustration that the solidstate floor selector disclosed in the application of Andrew F. Kirsch referred to above, will be utilized. That floor selector will advance to the next floor position when the control signal is momentarily interrupted. FIG. 10 shows a schematic wiring diagram of the notching switches wired for use with such a floor selector. A circuit is completed internally through the switch unless the appropriate plunger is depressed. For instance in the switch 193 current will flow internally between the terminals 2018' and 201B" unless the plunger 2018 is depressed by a floor stop. Current will flow through the other appropriately marked terminals under similar circumstances. It will be recognized then that if none of the plungers are depressed, a circuit w ill be completed between the external terminals L- and through terminal 2018', switch 201B, terminal 201B", lead 207, terminal 205B, lead 207, terminal 2058', switch 205B and terminal 2058'. Therefore, if either plunger 201B or 2 0 5B in the second row is depressed, the circuit between BL and L- will be interruptgd. Similar circuits can be traced between the terminals AL and L. The switch 195 is utilized to indicate when the floor stop is captured by the pawl. If neither of the plungers 203A or 203B is depressed by the floor stop, a circuit will be completed between the P-land P- terminals through terminal 2033".
switch 203B, terminal 203B, jumper 211, terminal 203A", switch 203A and terminal 203A. Therefore, the circuit between P+ and P- will be interrupted whenever a floor stop V in either row is opposite the switch 195.
A U-shaped bracket 213 is secured to the elbow of the control arm by screws 212 (see FIG. 2). As can be seen from FIG. 9, the U-shaped bracket supports a cam 215 with a sharp peak on it. A second longer cam 217 is mounted parallel to the cam 215 by a bracket 219. Two push switches 221 and 223 are supported by bracket 225 connected to the front support 41 so that their plungers are depressed by the cams 213 and 217, respectively when the control arm is in the vertical position. Since as will be seen below, the control arm is vertical only when the car is stopped exactly at a floor, the sharp peak on the cam 215 gives an accurate position of the car. The cam 217 is elongated and will activate the switch 223 even when the control head is displaced angularly a substantial distance from the vertical. The signal thus generated can be utilized for such well-known purposes as preopening doors as the car approaches a landing.
As was mentioned previously, the control arm and therefore the control head will rotate either clockwise or counterclockwise as viewed in FIG. 4 depending upon the direction of movement of the car as the car starts from a landing. As the control head approaches the horizontal position in either direction of rotation, the cam 217 will come in contact with and activate either the switch 227 or 229 as shown in FIG. 9. Energization of the switch 227 or 229 serves to disengage clutch mechanism 6" so that the clutch plate and therefore the threaded shaft 49 and control arm and head are decoupled from the advance gear 59 When the control arm reaches approximately the horizontal position it comes in contact with bumpers 235 on the top of stops 231 or 233 depending on the direction of rotation. As can be seen best from FIGS. 2 and 4, as the control head reaches the horizontal position, the appropriate spring arm comes in contact with a nylon bar 237 supported in a horizontal position by supports 239. The nylon bar is secured to the post by screws 24]. Since as will be seen, the pawling magnets will be energized until deceleration is to be initiated, the spring arm will not come in contact with the nylon bar until the control head is almost fully in a horizontal position. However, when energization is removed from the pawling coils, the nylon bar will prevent the spring 183 from extending the associated pawl.
When the car is to be brought to a stop, the pawling coil is deenergized. Although one of the pawls will be prevented from dropping by the nylon bar, the other pawl will be extended under the influence of its spring 183. For instance,
- referring to FIG. 4, if the car is going in a downward direction so that the helical coil is turning counterclockwise, the control head will be rotated 90 to the right after the car has reached maximum speed. As the pawling coil is deenergized, the nylon bar will prevent the pawl 153 from dropping however the pawl 151 will be extended. As the car approaches the floor, the floor stop will engage the pawl 151 and carry the control head with it in its counterclockwise direction. This will result in a reduction in the speed reference signal through rotation of the cam 71. As the car approaches the vertical position, the reference signal is reduced to zero and when the switch 221 is activated by the cam 215 indicating that the car is exactly at the floor, the car will come to a complete stop.
As can be seen in FIGS. 2 and 4 a cover plate 27 can be utilized to enclose the mechanism. It fastens to the front plate 41 and the turned up edges of the bottom plate 39.
OPERATION Although an understanding of the operation of the system can be appreciated from the description above, a description of a typical operation would be helpful at this point. Assume for the purposes of illustration that the car is standing at rest at the first floor. Under these conditions the helical carriage would be positioned as shown in FIG. 2 with the floor stop for the first floor between the extended pawls 151 and 153 on the control heads 65 which is in the vertical position. The cam 215 therefore would activate the switch 221 to indicate that the car was level with the floor as shown in FIG. 9. The cam 71 and cam follower 73 would be positioned as shown in FIG. 9 so that the potentiometer 83 would be set to its midpoint and would therefore generate a zero pattern potential. In addition, with the car at rest the clutch coils 112 and 113 would be deenergized so that the advance gear 59 would not be forced into contact with the clutch plate 6].
Assume now that a passenger enters the car and registers a car call for the third floor. The supervisory system will close the doors and prepare the car for upward travel. Through the circuits disclosed in the Caputo and Ostrander application mentioned above, a slight bias will be applied to the speed regulator to initiate movement of the car in the upward direction. At this point signals from these circuits perform two other functions. First, energization is provided to the clutch coils 112 and 113 thereby attracting the clutch armature 115 to the coils. This forces the operating pin 121 against the operating key 125 which moves axially in the longitudinal slot 127 in the threaded shaft 49. This in turn forces the advance gear 59 into engagement with the lip 62 on the clutch plate 61'. At this point the car has not yet begun to move. The control circuits also apply energization at this time to the pawling coils 141 and 143 thereby attracting the armatures 147 and 149 to lift the pawls 151 and 153 respectively clear of the floor stop for the first floor (see FIG. 6).
At this point the bias signal is applied to the speed controller to initiate movement of the car. The bias signal is applied linearly as a function of time to eliminate jerk and provide smooth acceleration. As the car begins to move, the drive tape 9 rotates the sprocket 11. For a clearer understanding of the relative motion of the components, reference should be made to the mechanical diagram of FIG. 11. The various components will rotate in the direction indicated by the arrows labeled with a U when the car is moving in the upward direction and in the direction indicated by the arrows labeled D when the car is traveling in the down direction. The control head of course will only move in the direction indicated by the appropriately labeled arrow while it is advancing. In addition, the helical carriage 47 will advance axially in a direction indicated by the appropriate arrow.
As the car begins to move upward then, the sprocket 11 will be rotated in the counterclockwise direction as seen in FIG. 9 by the drive tape 9. The drive shaft 35 will therefore also rotate in the counterclockwise direction as viewed in FIG. 4. This in turn will rotate the synchronous gear and therefore the helical frame 47 in the clockwise direction as viewed in FIG. 4. The advance gear 59 will be rotated in the counterclockwise direction by the spur gear 57. As the helical carriage 47 is rotated in a clockwise direction by the synchronous gear 55, the teeth in the hollow cylindrical nut 87 will engage the threaded shaft 49. The helical carriage 47 will advance axially to the right as viewed in FIG. 2 along the threaded shaft 49. The synchronous gear 55 will remain in engagement with the pinion gear 36 on the drive shaft 35 as the helical carriage advances axially. With the advance gear 59 forced into coupling engagement with the clutch plate 61 by the clutch mechanism 67, the threaded shaft 49 and therefore the control arm 63 carrying the control head will be rotated in the counterclockwise direction as viewed in FIG. 4. The threaded shaft 49 will therefore cause the cam 71 to rotate in a counterclockwise direction as viewed in FIG. 9. The shorter radius of the cam surface 72 presented to the cam follower 73 will cause the cam follower to rotate in a counterclockwise direction about the stub shaft 77 under the influence of the spring 76. The segment gear 79 connected to the end of the cam follower adjusts the effective resistance of the potentiometer 83 through the gear 81 so that a smoothly increasing reference signal of proper magnitude for travel in the up direction will be delivered to the speed regulator.
As the control arm begins to move in the counterclockwise direction the cam 215 will be carried with it thereby permitting the switch 221 to return to the unoperated position. Initial relative movement of the control head with respect to the floor stop 109 which for the first floor is in the A row, permits the plunger 203A to extend thereby completing the circuit between the P+ and P terminals in FIG. 13. Continued relative movement in the control head and helical carriage causes the floor stop 109A for the first floor to momentarily depress the plunger 201A on the switch 193 which momentarily causes an open circuit between the terminals E and L. This will cause the floor selector described in the Kirsch application mentioned above to notch to the second floor position. This notching occurs after the car has traveled only a very few inches although outside of the leveling zone so that the supervisory system has sufficient time to determine whether the stopping sequence should be initiated if the car is to stop at the second floor.
Continued movement of the car causes the control arm and control head to rotate further in the counterclockwise direction thereby increasing the speed reference signal as the cam 71 is rotated. As the control head approaches the horizontal position, the cam 217 will depress the plunger on the switch 227 (see FIG. 9). This will cause deenergization of the clutch coils 112 and 113 thereby removing the force urging the advance gear 59 into engagement with the clutch plate 61. Funher rotation of the control head in the counterclockwise direction will be restrained when the control arm 63 comes in contact with the bumper 235 on the stop 231. As the control head approaches the horizontal position, the spring arm 179 connected to the pawl 151 will come in contact with the nylon bar 237. Although both of the pawls will be in the retracted position at this point, since the pawling coils remain energized, this will insure that the pawl 151 cannot be extended.
With the control head in the horizontal position, the cam 71 remains stationary and the potentiometer remains set as the position which generates the maximum desired reference signal for the up direction. The car will therefore proceed upward at constant speed. As the control head, which represents the elevator car was advancing it was moving relative to the floor stop, which represents the position of the landing in the hatchway, at twice the rate at which the car was actually leaving the landing. Therefore the position of the control head relative to the floor stops represents the advance position of the car.
As the car approaches the second floor the floor stop 1093 in the B lane will pass under the control head. Since the car is not to stop at the second floor, the pawls 151 and 153 will remain retracted and will therefore not engage the floor stop. However the floor stop will momentarily depress first the plunger 205A then 2038 and finally'201B as it passes the now stationary contrcfliead. Interruption of the circuit between the terminals AL and L- will have no effect on the floor selector of the Kirsch application at this time. Similarly, the interruption of the circuit between the P+ and P- terminals by depression of the plunger 203A has no effect on the system at this time. However, when the car has moved a short distance above the second floor landing, and the stop for the second floor depresses the plun er 2018 to interrupt the circuit between the terminals BL and L- to the floor selector of the Kirsch application will be advanced to the third floor position.
Since it was assumed that a car call was registered for the third floor and since the supervisory system now has an indication that the elevator car is approaching the third floor, a stop signal will be generated. As can be seen by reference to the Caputo and Ostrander application, generation of the stopping signal results in deenergization of the pawling coils 141 and I43. The bias signal which was originally applied to start the car moving is removed at this time as a linear function of time. As the floor stop 109A3 for the third floor which is in the A lane approaches the control head, it morEitarily interrupts the circuit between the terminals BL and L- by depressing the plunger 2018. Again, since tlte fioor selector was advanced by an interruption in the BL signal by the second floor stop when the car left the second floor, this has no effect on the floor selector at this time. With the pawling coils deenergized the pawl 153 will be extended under the influence of a spring 183 acting on its spring arm 179. However, the pawl 151 will remain retracted since its spring arm 179 is restrained by the nylon bar 237.
As the floor stop continues to move relative to the control head, it will strike the extended pawl 153. The spring 169 will permit the stub shaft 157 around which the pawl 153 is pivoted to move slightly in the slot 163 to absorb the shock as the floor stop begins to push the control head in front of it.
.With the pawl I09A3 engaged by the pawl 153 it will depress the plunger 203B to interrupt the circuit between the P-land P- terminals in FIG. 13. This indication is used by the system of the C aputo and Ostrander application to prevent the clutch mechanism 67 from being engaged when the control head is pawled. As the floor stop lifts the control head of the pawl 151 will be extended behind the floor stop under the influence of its associated spring 183 as its spring arm 179 disengagesfrom the nylon bar 237. As the control head is rotated in a clockwise direction in synchronism with the helical carriage 47 as seen in FIG. 4, the cam 71 will be rotated in the clockwise direction as seen in FIG. 9. This will cause the cam followers 73 to move in the counterclockwise direction in FIG. 9 to return the potentiometer smoothly to the neutral position corresponding to zero pattern speed.
As the control head approaches the vertical position and reaches a point where the car is approximately 18 inches below the third floor, the cam 217 connected to the control arm 63 will activate the switch 223 to initiate opening of the car doors. As the car approaches the floor and the control arm reaches the vertical position, the cam 215 will activate the switch 221 indicating that the car is exactly at the floor and the brake will be set. By utilizing the helical frame to represent the distance between floors in the hatchway, the scale of the model is sufficiently large that when the control arm is in a position to depress the switch 221, the car is within plus or minus one-fourth inch of being in exact registry with the landing. Should the car overshoot or change position due to stretch or contraction of the elevator ropes as load enters or leaves the car, the system of the Caputo and Ostrander application will be effective to relevel the car.
Should due to a malfunction the pawls fail to extend, the car could approach the top or bottom of the hatchway at top speed. In order to preclude this happening, an elongated top stop 111 (see FIG. 2) will strike the forward post of the control head 65 and return it to the vertical position thereby bringing the car to a stop at the top floor without the top floor stop being engaged by the pawls. In order to provide the same protection should the control head fail to be picked up by the bottom floor stop as the car is traveling in the down direction, pins 243 and 245 are mounted in the abutting surfaces of the clutch plate 61 and the synchronous gear 55 (see FIG. 2). Since the helical carriage is traveling to the left as viewed in FIG. 2 when the car is traveling down, should the pawls fail to operate, the pin 245 will come in contact with the pin 243 and the clutch plate 61 will be rotated with the synchronous gear thereby bringing the control arm to the vertical position effecting stopping of the car.
ALTERNATE TRANSDUCER CONFIGURATIONS Although in the preferred embodiment of the invention, the output of the control mechanism takes the form of a device for setting the effective value of the potentiometer as discussed above, numerous variations are possible. Referring to FIG. 10, it can be seen that the potentiometer is replaced by a reactor having a U-shaped core 251 on which are mounted two coils 253 and 255. A cam 257 varies the reluctance of the magnetic circuit through the core in accordance with the angular position of the threaded shaft 49. As in the preferred embodiment, the output of this configuration is in the form of an electrical signal.
The speed reference signal generated by the control mechanism can also be produced in the form of a mechanical output as shown in the apparatus in FIGS. 13, 14 and 15. In this configuration the pattern signal is applied mechanically to a drag magnet regulator similar to that disclosed in US. Pat. No. 2,874,806 mentioned above. A cam follower 259 pivoted around the stub shaft 261 is angularly displaced in accordance with the position of cam 71 connected to the threaded shaft 49. Referring to FIG. 15 for a side view of the cam follower, it will be seen that a roller 263 mounted on the center rib 265 contacts the cam 71. The center rib is connected to two side ribs 267 and 269 which are pivoted about the stub shaft 261 by upper and lower tie bars 271 and 273, respectively. A pair of push rods 275 and 277 fit into the notches 279 (not shown) and 281 in the left-hand and right-hand side ribs, respectively.
The push rods 275 and 277 abut the upper legs of the H- shaped spring mount 283 of the drag magnet regulator. The lower legs of the spring mount 283 are connected by bolts 286 to a bracket 285 which is fastened to a support 287. Springs 289 acting against the bracket 291 connected to the support 287 and through the cup washer 293 urge the push rods and therefore the cam follower 259 against the cam 27].
Connected to the center of the crossbar of the H is an arm 295 made of nonmagnetic material, preferably aluminum. Also connected to the crossbar of the H is a C-shaped permanent magnet 297. A conductive disc 299 is mounted for rotation in the gap in the C-shaped permanent magnet 297. The disc 299 may be connected directly on the shaft of the elevator drive motor or connected to the drive sprocket 11. In any event, the disc 299 is rotated at a speed proportional to the actual speed of the car in the hatchway.
Connected to the free end of the arm 295 is a transducer armature 301 which is composed of a magnetic material. The transducer armature is free to move in the gap in the U-shaped cores of transformers 303 and 305. Wound on one leg of the U-shaped core 307 of the transformers 303 is a double primary winding 311. On the other leg of this core is a secondary winding 313. Similarly, double primary 315 is wound around one leg of the U-shaped core 309 of transformer 305 while the secondary coil 305 (not shown) forms the secondary of this transformer. A U-shaped support 319 a stop 321 to limit the travel of the arm in a clockwise direction as viewed in FIG. 14, while the support arm 323 mounts the stop 325 which limits the travel of the transducer armature in a counterclockwise direction. A pair of brackets 327 secures the transformers to the support 287. A pair of bias coils 329 and 331 connected to the support 287 by bolts 333 and 335 respectively, are mounted on either side of the arm 295. A bias bar 337 made of magnetic material is connected to the arm 295 adjacent the bias coils.
When the car is to be started energization is applied to the appropriate bias coil either 329 or 331. The attraction of the bias bar 337 by the appropriate coil causes the arm 295 to pivot about the pivot point 286 thereby moving the transducer armature 301 with respect to the cores of transformers 303 and 305. This effects the coupling between the primary and secondaries of these transformers and the resultant error signal is applied to the exciter field of the generator in the well-known Ward-Leonard direct current drive system thereby causing the car to begin moving. As the car begins to move and the threaded shaft 49 is rotated by the advance gear, the cam follower 259 follows the contour of the cam 71. In following the movement of the cam follower 259, the push rods 275 and 277, in cooperation with the springs 289, deflect the upper legs of the H-shaped spring mount 283. This causes the arm 295 to displace the transducer armature further in the same direction. As the car begins to move, the disc 299 rotates in synchronism therewith. Eddy currents induced in the conductive disc 299 by the permanent magnet 297 exert a deflecting force on the magnet thereby also tending to deflect the position of the arm. The deflection caused by the forces acting on the permanent magnet tend to deflect the transducer armature in the opposite direction from that induced by the push rods 275 and 277. Therefore, when the actual speed of the car is equal to the speed called for by the deflection caused by the push rods, the transducer armature will be returned to the neutral position and the car will maintain constant speed. Stops 321 and 325 limit the deflection of the transducer armature and therefore place limits on the acceleration that may be obtained. Of course the transformer output of the magnet regulator could be replaced by the resistor piles utilized in U.S. Pat. No. 2,874,806 mentionedabove.
As another variant, the push rods could be replaced by a voice coil mounted on the arm 295 in the vicinity of the bias bar 337. With the bias coils replaced'by permanent magnets, a pattern signal could be applied to the drag magnet regulator in the form of an electrical signal proportional to the setting of a potentiometer as in the preferred embodiment of the invention or the reactance of a reactor as in the embodiment disclosed in FIG. 12.
Numerous other modifications all within the spirit of the invention could obviously be applied to the apparatus disclosed herein.
l. A reference signal pattern generator adaptable for use with a speed control system including a nonmovable element, a movable element mounted for movement relative to the nonmovable element and a speed regulator operative to regulate the speed of the movable element in accordance with a speed reference signal generated by the reference signal pattern generator, said pattern generator comprising a movable member movable in a first direction from a neutral position in synchronism with the movable element as said movable element begins to move in a first direction, means connected to' the movable member to generate said speed reference signal as a function of the displacement of said movable member from the neutral position, limit means for limiting the displacement of the movable member from the neutral position to a position corresponding to a predetermined maximum speed reference signal, and means for engaging and moving said movable member in a second direction opposite to said first direction in synchronism with the movement of the movable element in its first direction to return said movable member to the neutral position, thereby slowing down the' movement of the movable element in the first direction when it is desired that said movable element be brought to a stop.
2. The reference signal pattern generator of claim 1' wherein the movable member moves in the second direction from the neutral position when said movable element begins to move in a second direction, wherein the speed reference signal generated when the movable element is displaced in said second direction from the neutral position is opposite in polarity to the signal generated when the movable member is displaced in the first direction from the neutral position and including means for engaging and moving said movable member in the first direction in synchronism with the movement of the movable element in its second direction to return said movable member to the neutral position when it is desired to stop the movement of the movable element in thesecond direction.
3. The reference signal pattern generator of claim 2 including bias means for generating an initial speed reference signal of the proper polarity to cause the speed'regulator to start the movable element moving in the desired direction.
4. A speed pattern generator adaptable for use in an'elevator system including a structure having a plurality of floors, an' elevator car mounted for movement relative to the'structure to serve the landings and a speed'regulator for controlling 'thespeed of the elevator car in response to a speed pattern signal generated by the speed pattern generator, said speed'pattern generator comprising a first movable member movable in synchronism with the elevator car, a secondmovable member movable from a neutral position in synchronism with the car in a direction opposite to the movement of the first movable member along a path parallel to and in close proximity tothe' path of the first movable member as the elevator car begins to move, pattern means for generating a speed pattern signal as a function of the displacement of the second movable member from said neutral position and stopping means'for'couplir'tgsaid second movable member to said first movablem'embe'r for movement thereby so that saidsecond movable:member'is' returned to said neutral position effecting areduction in the speed pattern signal.
5. The speed pattern generator of claim 4 including -limit means operative to limit the displacement of the secondrnova ble member from the neutral position.
6. The speed pattern generator of claim 5 including: bias means for producing an initial speed pattern signalsufi'rc'ie'rit to cause the car to begin moving;
7. The speed pattern generator of claim 5 wherein' the: stopping means includes floor stops distributed alongthe'firstfmovable member at points proportional to the position-ofthe floors relative to the structure, said stopping means. also' including a retractable pawl mounted on said secondmovable" member and movable between a retracted positionwh'ere'in said pawl is not engaged by the floor stops on the first'movable member during relative movement of the two movable 'm'em hers and an extended position wherein the pawl is engaged by the floor stops whereby said second movable member is returned to the neutral position by the first movable member as it moves in synchronism with the elevator car.
8. The speed pattern generator of claim 7 wherein said first movable member is generally cylindrical in form and is mounted for compound rotational and axial movement in synchronism with the elevator car, said floor stops being mounted in the helical path traced on the curved surface of the cylindrical form as the first movable member moves relative to the neutral position of the second movable member, said second movable member being in the form of an arm pivoted for movement about the axis of the first movable member with a control head carrying the pawl extending parallel to the axis of the first movable member from the end of the am and positioned relative to the first movable member so that the floor stops pass in close proximity to the control head as the first movable member is driven in synchronism with the elevator car.
9. The speed pattern generator of claim 8 wherein the first movable member is a helix, wherein the arm is fixedly attached to a threaded shaft passing through the axis of the helix, the thread having the same pitch as that of the helix and wherein the helix is threadedly engaged by said shaft whereby as said helix is rotationally driven in synchronism with the.
elevator car, the helix moves axially with respect to the control head causing said floor stops to successively pass in close proximity to the control head.
10. The speed pattern generator of claim 9 wherein said helix is rotationally driven by a driving gear concentrically mounted on one end of the helix, and a drive shaft which is rotated in synchronism with the movement of the elevator car and is mounted parallel to the axis of the helix, said drive shaft having evenly spaced longitudinal teeth around its periphery for a substantial length forming an elongated pinion gear which meshes with said driving gear whereby said driving gear remains in mesh with the drive shaft as the helix threadedly advances longitudinally on the threaded shaft.
11. The speed regulator of claim 10 wherein said arm of the second movable member is rotationally displaced from its neutral position in synchronism with the movement of the car by rotation of the threaded shaft through a clutch plate fixedly attached to the threaded shaft, an idler gear driven by the drive shaft, an advance gear driven in a direction opposite to that of the helix by the idler gear, said advance gear being journaled for free rotation about the threaded shaft and clutch means operative upon startup of the car to urge the advance gear axially on the threaded shaft into coupling engagement with said clutch plate whereby said threaded shaft and second movable member are rotated in the direction opposite to the direction of rotation of said helix.
12. The speed pattern generator of claim 11 wherein said pattern means includes a cam connected to the threaded shaft, a cam follower biased against said cam, and a transducer operative to generate an electrical signal with an amplitude which is a function of the displacement of said cam follower.
13. The speed pattern generator of claim 11 wherein said pattern means includes a cam connected to the threaded shaft, a cam follower biased against said cam, and means connected to said cam follower for applying a force to the arm of a drag magnet regulator, said force being proportional to the displacement of the cam follower.
14. The speed pattern generator of claim 11 including means responsive to the limit means to disengage said clutch means when the arm has advanced to the position correspond,
ing to the maximum predetermined pattern signal.
15. The system of claim 11 wherein the arm is displaced from the neutral position in a first direction to cause the pat tern generator to produce a signal of a first polarity when the drive shaft rotates in a first direction in response to upward movement of the elevator car and wherein said arm is displaced from the neutral position in the second direction to cause the pattern generator to produce a signal of the opposite polarity when the drive shaft rotates in the second direction in res onse to the downward movement of the elevator car.
6. The speed pattern generator of claim 15 including two pawls connected to the control head, the first pawl being operative when extended to engage a floor stop on the helix and thereby return the arm to the neutral position when said arm has been displaced in the first direction for the neutral position and the second pawl being operative when extended to engage a floor stop on the helix and thereby return the arm to the neutral position when said arm has been displaced in the second direction from the neutral position, the stopping means including means to operate the pawls to the extended position when the elevator car is to be brought to a stop.
17. The speed pattern generator of claim 16 including switch means mounted on said control head and operative to produce signals as said floor stops on the helix pass under said control head and control means responsive to said switch means for effecting control of the elevator car.
18. The speed pattern generator of claim 17 including support means and switch means having a first operating member mounted on the arm and a second operating member mounted on the support means, said switch being operated from a first to a second condition to affect control by said control means when said first and second operating members come in com tact with each other at selected points of travel of the arm.