US 3316469 A
Description (OCR text may contain errors)
April 25, 1967 P, A. m KE 3,316,469
PLURAL MOTOR REMOTE CONTROL SYSTEM Filed Sept. 3, 196.3 5 Sheets-Sheet l- I I 52 IUZJ l 76 an l t 20 I00 i I44 74 6 90 ,n I 84 68 I l4 INVENTOR. PflUL A O/C/(E 14/5 4 TTOEA/EVS April 25, 1967 P. A. DICKE 3,316,469 f PLURAL MOTOR REMOTE CONTROL SYSTEM Filed Sept. 5, 1963 I 5 Sheets-Sheet 2 m, y y
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PLURAL MOTOR REMOTE CONTROL SYSTEM Filed Se t. 3, 1963 3 Sheets-Sheet s INVENTOR. 5e 58 7 P401. ,0. 0/6/65 60b BY HIS flTTOEA/EYS United States Patent 3,316,469 .PLURAL MOTOR REMOTE CONTROL SYSTEM Paul A. Dicke, New Bremen, Ohio, assignor to Crown Controls Corporation, New Bremen, Ohio, a corporation of Ohio I Filed Sept. 3, 1963, Ser. No. 305,936 8 Claims. (Cl. 318-41) This invention relates to a remote control system and more particularly to a remote control system for use with an antenna rotator, although not necessarily so limted. ,At present, the usual antenna rotators drive radio or television antennas at a speed approximating one revolution per minute. Although it would be desirable to position antennas in an optimum direction at a faster speed, one revolution per minute has been considered the fastest acceptable rate. Due to the weight and length of an- .tennas, acceleration to a faster rotational speed could create too great a torque on the antenna mast when initiating the rotational drive. Also, the momentum of an antenna rotating at a faster speed, when suddenly stopped, may cause the antenna to overrun and thus, it may not be in precisely the position desired or indicated at the control point. Moreover, the user of the antenna rotator control may not know, in advance, the precise antenna position for optimum reception. Therefore, the user must often feather in to the precise antenna direction desired. For example, if the antenna is used in connection with a household television receiver, the user would observe the television picture and set the antenna to that position which results in the clearest picture. If the antenna rotates at too great a speed, such feathering in would be difiicult due to the tendency to overrun.
An object of this invention is the provision of a method and apparatus for increasing the acceptable speed of rotatable antenna drives. In accordance with this invention, an antenna is driven at one rate during the initial and final stages of rotation and at another, faster rate during the remaining portion of its rotation. For example, the antenna may be driven at one revolution per minute'during the first and last few degrees of travel and at two revolutions per minute throughout the remainder of travel. With a more elaborate system, the antenna may be rotated at even greater speeds by gradually increasing the rotational speed at the beginning of travel and gradually decreasing the speed at the end of travel. Accordingly, a further object of this inventnon is to provide apparatus for increasing and decreasing the rotational speed of an antenna during its travel.
In my copending application for United States Letters Patent entitled, Plural Motor Remote Control System, Ser. No. 39,840, filed in the United States Patent Office on June 30, 1960, now Patent No. 3,102,218, a plural motor remote control system which may be used as an automatic antenna rotator is described. This system utilizes similar proximal motors and servo or distal motors, each having two sets of field windings cooperating. for driving the motors in a selected direction. The distal motor is selected so as to have a speed slightly greater, although not much greater, than the speed of the proximal motor, so that when the distal motor drives a load, such as an antenna, the load slows the distal motor so as to have substantially the same rate of speed as the proximal motor. Thus, the two motors are substantially in synchronism. A switch mechanism is described in said aforementioned patent application having three positions, one is a neutral position, one is for clockwise movement of the proximal motor, and another for counterclockwise movement thereof. The switch also includes an actuator having a linear travel for actuating the switch mechanism from one position to another.- The actuator in turn is controlled by a cam mechanism and a cam'follower, the ca'm"mechanism having 'twohohcehtric cam surfaces, one of which has a larger diameter than the other, one 'for clockwise movement and one for counterclockwise movement. The two concentric cam surfaces are connected by a diagonal -surface,the midpoint of which places the switch actuator in the neutral or ofi? position. The cam member may be manually moved to actuate the switchmechanism, causing the distal motor to rotate either in a clockwise or in acounterclockwise direction. The proximal motor is actuated at the same time to drivethe cam follower 'back to the diagonal, neutral or off position. Thus, as the distal motor drives the load, the proximal motor drives a cam actuated switch mechanism to its off position. The instant invention is described herein with relation to such an automatic rotator control. It is to be understood, however, that the instant invention may also be used in connection with a manual or semi-automatic antenna rotator.
A further object of this invention is to provide a simple switching device in association with the control for a proximal motor for actuating a distal motor.
Another object of this invention is to provide a simple switching device for varying the speeds of rotation of units driven by a proximal motor and a distal motor.
Still another object of this invention is to provide a simple solenoid controlled variable gear mechanism.
Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture and the mode of operation, as will become more apparent from the following description.
In the drawings:
FIGURE 1 is a perspective view of a control unit made in accordance with this invention.
FIGURE 2 is a cross-sectional view of the control unit of FIGURE 1.
FIGURE 3 is a unit of FIGURE 1.
FIGURE 4 is a plan view of a switch used in the control mechanism.
FIGURE 5 is a cross-sectional view of a portion of the switch, as viewed in the direction of arrows 5--5 of plan view of a cam used in control FIGURE 4.
FIGURE 6 is an enlarged view of a portion of a drive mechanism made in accordance with this invention.
FIGURE 7 is a schematic wiring diagramof the control system made in accordance withthis invention.
FIGURE 8 is a schematic illustration of a modified control system made in accordance with this invention.
Referring to the drawings in greater'detail and in particular. to FIGURES 1 and.2, the reference character 10 indicates broadly the housing fora control unit made in accordance with this invention. The control unit includes a control or proximal motor 14, a transformer 16, a switch mechanism 18, an adjustable cam 20 and a pointer 22.
Referring to FIGURES 6 and 7, an antenna drive, servo or distal motor 24 is connected in parallel with the proximal motor 14. As will be described below, the distal motor 24 is mounted in close proximity to an antenna mast and is driven substantially in synchronism with the. motor 14. Although the motors are not synchronous, the .motors have been selected with such speed characteristics that the two motors have substantially identical speeds under normal load conditions. In order to prevent the antenna leads from being twisted, it is necessary to confine the rotary motion of the distal motor 24 in each direction to one revolution of the antenna driven thereby plus a few degrees as, for example,
of the transformer 16 has one terminal grounded at 30,
the grounded terminal being series connected to one terminal of each of the windings 32 and 34 of the motor 14 and to one terminal of each of the windings 36 and 38 of the distal motor 24. The switch mechanism 18 may have a contact 40 adapted to be series connected through a movable contact 50 to the secondary winding of the transformer 16 to supply electrical energy directly to the windings 34 and 38. A phase-shifting impedance, such as a condenser 42, connects the ungrounded terminals of the windings 32 and 36 to the contact 40. By this arrangement, as is well known to those skilled in the art, a leading current is supplied to the windings 32 and 36, which current leads the current supplied to the windings 34 and 38. This will cause the motors 14 and 24 to rotate in one direction. By shifting the contact 50 from the contact 40 to a contact 44, the current from the secondary winding of the transformer 16 is then supplied to the ungrounded terminals of the windings 32 and 36, the leading current being then supplied. to the ungrounded terminals of the windings 34 and 38, thus reversing the direction of the motors 14 and 24.
' Referring to FIGURE 4, in connection with FIGURE 7, the switch mechanism 18 for accomplishing the reversal of direction of rotation of the motors 14 and 24 is as follows. The movable contact 50 is mounted upon an actuating bar 52 that is slidably mounted such that the contact 50 may be selectively engaged with a centrally located open contact 54 and either of the contacts 40 and 44. Mounted upon the opposite-side of the actuating bar 52 from the contact 50 is anothermovable contact 56 adapted to engage an open transformer contact 58 when the contact 50 is engaged only'with the contact 54. Note that the contacts 50 and 54 are shorter than the separation'be tween the contacts 40 and 44, so that the 'onlyopen contacts 54 and 58 may be engaged by the contacts 50 and 56, respectively. When the actuating bar 52 is moved such that the contact 50 engages the contact 40, the contact 56 will then be in engagement with a transformer contact 60a, which completes a circuit through the primary winding of the transformers 16 and the source S. Similarly, when the actuating bar 52 is positioned to place the contact 50 in engagement with the contact 44, the contact 56 will be engaged with a transformer'contact 60b. The contacts 60a and 60b are connected together such that the primary winding of the transformer 16 is connected to the source S regardless of which of the contacts 60a or 60b is engaged by the contact 56. As apparent from an inspection of FIGURES 4 arid 7, the movable contact 50 is also adapted to engage a contact 40a and a contact 44a which are, respectively, electrically thesame as the contacts 40 and 44. At' the same time, the movable contact 56 is adapted to engage fixed contacts 600 and 60d'at the extreme ends of movement of the actuating bar 52, which contacts are electrically identical to the contacts 60a and'60b. The latter contacts 40a, 44a, 60c and 60d are required for actuation of a speed change mechanism which will be described in detail below.
The fixed switch contacts40, 40a, 44, 44a, 54, 58 and 60a through 60d are mounted on spaced support members 64, there being five such support members 64 on each side of the actuating bar 52. For clarity, the spacing between the support 64 is somewhat magnified in FIGURE 2. Support for the members 64 is provided by a switch support plate 66 rotatably mounted in a bushing 68, which in turn is mounted in a frame member 74 fixedly mounted upon a bracket 76 supported in the bottom of the housing 10. The switch support plate 66 is provided with a downwardly extending annular geared flange 78 having internal gear teeth 80 meshing with a pinion 82 mounted for rotation upon the frame member 74. The pinion 82 is driven by a drive gear 84, which in turn is rotated by a variable speed gear mechanism, generally designated 86, to be described below. The input gear 88 of the gear mechanism 86 derives its rotation from a pinion 90 driven by the motor 14. As will appear below, when the motor 14 rotates in one direction, the entire switch mechanism mounted upon the plate 66 rot-ates in a clockwise direction and when the motor 14 rotates in the opposite direction, the switch mechanism rotates in a counterclockwise direction.
The mechanism for driving the actuating bar 52, and accordingly controlling the switch mechanism 18, is illustrated in FIGURES 2, 3 and 4 and includes the cam member 20, which has a cam groove 102 therein, within which is received a cam follower pin 104 mounted on one end of the actuating bar 52. The cam member 20 has a pcripheral portion mounted for rotation on the frame member 74. A cover plate 106 for the housing 10 has a plurality of depending hooks 108 projecting through cooperating apertures in the peripheral portion 100 of the cam 20 such that one may manually rotate the cover member 106 in turn to rotate the cam 20. Notations may be made on a scale 110 on the control housing 10, the notions cooperating with an indicant 106a, whereby the user of the device may set the indicant 106a to a selected position on the scale 110 which corresponds to a desired direction of antenna position.
Referring to FIGURE 3, the cam groove 102 consists of an outer circular portion 102aand an inner circular portion 102b connected by a generally diagonal or median connecting portion designated 1020. The cam grooves 102 and 102b provide two concentric, radially offset cam surfaces and the diagonal or median portion 1020 provides a plurality of radially decreasing cam surface steps, designated 102d, 102a and 102 The cam follower pin 104, and thus the bar 52, are moved linearly only when the pin 104 is slidingly engaged with one of the radially decreasing steps 102d, 1022 or 102 If the cam follower pin 104 is in the grooved portion 102a, the contact 50 is engaged with contacts 44 and 44a and the motor 14 drives the cam follower 104 in a clockwise direction, as viewed in FIGURE 3. Since the cam portion 102a is circular, the actuating bar 52 is not moved relative to the fixed contacts 44 and 44a during the travel of the pin 104 in the groove 102a. As the pin 104 engages the portion 102d, the bar 52 is movedrelative to the fixed contacts until the cam follower 104 reaches substantially the midpoint of the center step 102 of the connecting groove 102a, at which time only the open contacts 54 and 58 are engaged by the contacts 50 and 56, respectively. Thereupon, both the motor 14 and the motor 24 are disconnected from the source S and the rotation of the motors14 and 24 will be arrested. If the cam follower 104 is'located in the inner groove 102b, as viewed in FIGURE 3, the cam follower 104 will similarly be rotated in a counterclockwise direction until it reaches the midpoint of the step 102f, whereupon the switch 18 will again be open-circuited.
The pointer 22 is mounted by pins upon spaced flange members 122, 124, 126 and 128, which have opposed surfaces providing a guideway for the actuating bar 52; The midportion, designated 106b, of the cover plate 106 is transparent so that the pointer 22 may be viewed from above the housing 10. As the motor 14 drives the cam follower support plate 66, in turn causing the switch 18 to be actuated, the pointer 22 rotates into a position aligned with the indicant 106a- The relationship between the pointer 22 and the indicant 106a is such that they will be aligned when the cam follower 104 arrives at the neutral or off position 102i and the rotation of the motors 14 and 24 is thus arrested. Of course, due to the substantial synchronism of the motors 14 and 24, the position of the pointer 22 indicates the antenna position at all times. i v
. The operation of the mechanism thus far described will be apparent to' those skilled in the art. The antenna drive or distal motor 24, which is drivingly connected to the antenna mast 150 in any suitable fashion, causes the antenna to rotate if the cam member 20 is rotated to any selected position out of alignment with the pointer 22. This occurs because the cam follower pin 104 is thereby located in one of the circular cam grooves 102a or 102b, causing both the motors 14 and 24 to rotate. The distal motor 24 rotates the antenna while, at the same time, the proximal motor 14 rotates the cam follower pin 104 toward the cam step 102 such that both motors are arrested when the antenna reaches the optimum position for the selected radio or television station. The structure and operation of the motor control system thus far described is similar to that described in my aforementioned copending application Ser. No. 39,840.
It will be appreciated that, by the provision of the several steps in the cam groove 102, it is possible to actuate several switches or other mechanisms for changing the rotational speed of the antenna mast 150 and of the cam follower pin 104. In accordance with this invention, it is desired that the speed of rotation of the antenna be increased by increments up to a maximum speed and as it comes to the end of its travel, the speed of rotation of the antenna is decreased by increments. This is accomplished in the embodiment disclosed herein by utilizing the steps 102d and 102a in the cam groove 102, the portions 102a and 102a being on each side of the median step 102 and separated therefrom by radially offset steps 102g and 102b, respectively. As the cam 20 is rotated relative to the cam follower pin 104, so as to offset the cam follower position from the neutral, median position 1021, either the contact 40 or the contact 44 is engaged by the contact 50, whereupon the antenna is rotated at substantially one revolution per minute. The initial rotational speed re mains constant while the pin 104 moves along the steps 102g and 10211. As the cam follower pin 104 moves along the radially varying steps 102d or 102e toward either the groove 102a or 1021;, the bar 52 is moved relative to the fixed contacts to actuate mechanism for changing the rotational speed of the antenna. The mechanism for changing the speed of rotation of the antenna could take a variety of forms. motors could be used. The presently preferred embodiment disclosed herein is to provide switch controlled means for varying the gear mechanism 86 between the motor 24 and the antenna mast 150. This gear mechanism 86 is identicalfor both the antenna drive, shown in FIGURE 6, and for the cam follower drive, shown in FIGURE 2.
schematically illustrated in FIGURE 6 is the rotatable antenna mast 150, upon which is affixed an antenna drive gear 152 driven by the output gear 154 of the antenna gear drive mechanism 86 mounted upon a bracket 156 that in turn is supported upon a suitable fixed support 158. The gear mechanism 86 includes a center shaft 160, which is mounted for rotary and lineal movement within a pair of spaced bearing members 162 supported by the bracket 156. A comparison of FIGURES 2 and 6 will reveal that the pinion 90 may either be cut into the surface of the output shaft of the motor associated therewith, as indicated in FIGURE 6, or may be splined therein, as indicated in FIGURE 2. The input gear 88, which is coaxial with the center shaft 160, derives its support from an enlarged portion 164 of the shaft 160.
Mounted upon the input gear 88 on an axis offset from the shaft 160 is a vertically upright spindle support 88a for a two-part planet gear 166 having a smaller geared portion 166a meshed with the teeth of a sun gear 168 fixedly connected to and coaxial with the center shaft 160. The larger geared portion, designated 166b, of theplanet gear 166 is meshed with the teeth of a ring gear 170, which is mounted upon the same plate, designated 172, to which the output gear 154 isrnounted. Both For example, variable speed gears 154 and 170 are also coaxial with the center shaft 160. A first annular friction clutch plate 174 is affixed to the base of the ring gear 170 and a second annular friction clutch plate 176 is affixed to the top of the input gear 88. The center shaft 160, and accordingly the por tion 164 and the input gear 88 are biased vertically upwardly, as viewed in FIGURE 6, by a spring member 178 aflixed to the lower leg of the bracket 156. So long as the center shaft 160 is so biased upwardly, creating engagement of the clutch plates 174 and 176, which is the position illustrated in FIGURE 6, there is a direct reduction drive between the pinion 90 and the output gear 154, since the gears 88, 166, 168 and 154 rotate as a unit; The gear reduction is so designed that the member is rotated at substantially one revolution per minute.
Supported upon the lower leg of the bracket 156 and coaxial with the shaft 160 is an annular solenoid 140 including a solenoid coil 140a nested within a hollow cup-shaped housing or support member 1 40b, having a vertically oriented, annular outer periphery. The arma ture of the solenoid 140 comprises a clutch disc 1400 integral with or aflixed to the center shaft 160. 1 Upon energization of the solenoid coil 140a, the disc 1400 is' drawn into engagement with the top surface of the member 1401). The top surface of the portion 14% and the lower surface of the clutch disc 1400 constitute friction clutch surfaces such that, when engaged, the disc 140a cannot rotate. Accordingly, the center shaft 160 and the sun gear 168 carried thereby will be restrained from rota tion. At the same time, the portion 164 lowers with the clutch disc 140e, whereupon the clutch plate 176 becomes disengaged from the clutch plate 174 so that the gear 88 may rotate relative to the gear 170. As apparent, when the pinion 90 is then rotated, the planet gear 166 will revolve about the sun gear 168 creating a faster drive for the ring gear 170 and, therefore, the output gear 154. Thus, when the solenoid 140 is energized, the speed of rotation of the output gear 154 and, accordingly, the load driven thereby, is increased. gear mechanism 86 is so designed that the output speed is independent of the direction of rotation, also it may be observed in FIGURE 5 that parts of gear mechanism which are fixedly connected together, such as the sun gear 168 and the shaft 160, may be integral.
Since identical gear assemblies 86 and speed change ground 30 and another terminal connected to switch con' tacts 142 mounted on a pair of support members 64at' opposite ends of the array of members 64. The contacts 142 are adapted to be engaged by a sliding contact 144 (see FIGURE 5) carried by the actuating bar 52 and spaced from the movable contact 50. The movable contact 144 also engages a plurality of open contacts 146 intermediate the two contacts 142. As apparent, when the cam 20 is rotated such that the cam follower pin 104 is located within the cam portions 102g or 10211, the contact 144 will not have contacted either of the contacts 142. The solenoids 140 thus are not energized. However, as the cam 20 is rotated such that the cam follower is relatively moved with respect to the cam groove 102 such that it passes along either of the grooved portions 102d or 102e, the bar 52 is moved linearly whereupon the contact 144 engages one of the contacts 142, causing both solenoids 140 to be energized.
FIGURE 8 schematically illustrates a more elaborate speed change system. A cam groove 202 is illustrated having diagonal portions 202a, 202b, 2020, 202d and 2022 therein. A cam follower 204 is shown located in the cam groove 202 with an actuating bar 252 attached thereto adapted to drive a contact member 250 relative It should be noted that the Referring to FIGURE 7," both solenoids 140 have one terminal connected to the' to a plurality of spaced contact elements 260, 262, 264, 266, 268 and 270. The line connection to the contact member 250 is indicated by contact member 272. It will be appreciated that, as the cam groove 202 moves relative to the cam follower 204, the contact member 250 will selectively engage the various contacts 260, 262, 264, 266, 268 and 270. The various contact members 260 through 270 may be used to control either mechanical, electrical, or electrical-mechanical means for changing the speed of rotation of the proximal and distal motors 14 and 2 4 or the loads driven thereby. Therefore, it may be seen that by providing the more elaborate cam groove 202, a variety of rotational speeds may be made available. Of course, it is to be understood that FIGURE 8 is only schematic and that the cam groove 202 will actually be arcuate, each of the diagonal portions 202a through 202e being radially offset, as in the case of the cam groove 102 shown in FIGURE 2. Similarly, the various elements 250 through 272 may correspond to the elements of the switch 18 shown .in FIGURE 4.
In review, in the embodiment described in FIGURES 1 through 7, the motors 14 and 24 are rotated at substantially one revolution per minute when the pin 104 is located in either cam step 1023 or 102k, because the contact is accordingly engaged with either the contact 40 or the contact 44. As the cam follower 104 is moved relative to the cam groove 102 along either groove portion 102d or 102e, the solenoids 140 are energized, since the movable contact 144 engages one of the fixed contacts 142. Upon energization of the solenoids 140, the rotational speed of the output gears 154 is increased. This speed increase may be of the order of 2 to 2.5 times the initial rotary speed of the gears 154. Accordingly, the antenna will be driven at two or two and one-half revolutions per minute. The initial relative movement of the cam follower 104 relative to the cam groove 102 is caused by rotation of the cam member 20 upon manual rotation of the cover member 106. Thereafter, the proximal or control motor 14 drives the cam follower 104 back to the midpoint of the step 102i. As the cam follower 104 is so driven, if located in either groove portion 102a or 102b, the antenna 150 will be driven at the increased speed.
When the cam follower reaches the step 102d or 1022, as the case may be, the antenna speed is reduced to substantially one revolution per minute. The rotation of the motors 14 and 24 is then arrested when the cam follower reaches the step 102i. Thus, the antenna speed is automatically increased up to a faster rate than presently deemed acceptable. At the same time, there is no great surge of torque upon the antenna mast because the initial speed approximates one revolution per minute. Similarly, it is possible to accurately feather in to an optimum antenna direction, since the antenna speed slows to one revolution per minute before coming to a stop. The steps 102g and 102k may represent approximately 10 of antenna rotation so that minor antenna direction adjustments may easily be made with the antenna rotating at only one revolution per minute within 10 on each side of the antenna position. The system schematically illustrated in FIGURE 8 provides a further extension of the principle disclosed in FIGURES 1 through 7.
Although the presently preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportions and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a'device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.
Having thus described my invention, I claim:
1. The combination including:
an energy source, a reversible antenna drive motor;
means connecting said motor to an antenna for rotation thereof, said means connecting said motor to an antenna including a variable speed gear mechanism and speed change means connected to said variable speed gear mechanism, said speed change means including mechanism varying the ratio between the input and output of said gear mechanism by operation of said speed change means;
switch means connecting said energy source to said drive motor for selectively actuating said motor in a forward or a reverse direction to thereby rotate said antenna in a forward or reverse direction, said switch means including a switch setting means connected to said switch, said switch setting means including a manually rotatable cam having an arcuate cam surface and a cam follower connected to said slidable switch actuator and operatively engaged by said cam surface for setting the switch position, portions of said cam surface having a changing radius for shifting said switch from one position to another, said switch means being connected to said speed change means so that said speed change means is actuated at predetermined relative positions of said cam and said cam follower;
a control motor, said control motor being adapted to be connected to said energy course through said switch means, said control motor being connected to drive said cam follower with respect to said cam surface from a manually selected position wherein said switch means connects said energy source to said control motor toward a surface portion of said cam in which said follower causes said switch to disconnect said drive motor from said source.
2. The structure of claim 1 wherein said control motor is connected to said source by said switch means whereby said control motor is disconnected from said source when said drive motor is disconnected from said source, wherein said control motor is connected to said cam follower by means including a variable gear mechanism substantially identical to said aforementioned variable gear mechanism, and wherein additional speed change means controlled by said switch means varies the speed of said cam follower when the speed of said antenna is changed.
3. The combination including:
an energy source, a proximal motor, a distal motor for driving a load;
switch means connected between said energy source, and said proximal motor'and said energy source and said distal motor, said switch means including a movable actuator capable of being positioned in a plurality of different positions and carrying a plurality of switch contacts connectable in its different positions, said switch means further comprising a cam follower connected to said actuator, said switch means further including a cam member having two concentric surfaces, one of which has a larger radius than the other, and a diagonal cam surface connecting between said concentric cam surfaces, said cam follower being in contact with one of said cam surfaces, said diagonal cam surface having a plurality of steps of decreasing radius, said proximal motor being connected to control the position of said cam with respect to said cam follower whereby said switch means is moved to a plurality of different positions upon relative movement of said cam member and said cam follower.
4. The structure of claim 3 wherein cam follower drive means connects said proximal motor to said cam follower, and said cam follower, when engaged with one of said steps of said cam member, actuates said switch to an off position thereby disconnecting said motors from said energy source, said cam follower drive means causing said cam follower to move along said cam surfaces toward said one of said steps until said follower is engaged with said one of said steps.
5. The structure of claim 4 wherein said distal motor is connected to a load by a variable speed gear mechanism and said cam followerdrive means includes a substantially identical variable speed gear mechanism, the output speeds of said gear mechanisms being controlled by a pair of solenoids, one for each gear mechanism, connected to said source by said switch means, said switch means being constructed to cause said solenoids to be energized at the same time.
6. The structure of claim 4 wherein said cam follower drive means includes a variable speed gear mechanism, said gear mechanism comprising, a center shaft, support means mounting said shaft for rotation about and lineal movement along a fixed axis, a sun gear fixedly connected to said shaft for rotation about said axis, an input gear driven by said proximal motor and supported on said shaft for rotation about said axis, a ring gear mounted for rotation on said shaft about said axis, an output gear connected to said cam follower and connected to said ring gear and coaxial therewith, a planet gear mounted on said input gear for rotation about an axis offset from said fixed axis, said planet gear including a first geared portion meshed with said sun gear and a second geared portion meshed with said ring gear, first clutch means locking said input gear to said ring gear whereby said input gear and said output gear rotate together, means actuating said first clutch means, speed change means releasing said first clutch means whereby said ring gear may rotate relative to said input gear, and second clutch means actuated by said speed change means restraining rotation of said shaft and thereby said sun gear when said first clutch means is released whereby said planet gear revolves about said sun gear as said input gear rotates.
7. The structure of claim '6 wherein said first clutch means comprises cooperating clutch plates on said input gear and said ring gear, said means actuating said first clutch means comprising bias means biasing said center shaft such that said clutch plates are engaged, and said speed change means includes a solenoid cooperating with said shaft to overcome said bias means, the operation of said solenoid being controlled by said switch means.
8. The structure of claim 7 wherein said solenoid includes a housing, a coil disposed within said housing, an armature plate afiixed to said center shaft, said plate being drawn toward said housing upon energization of said coil, and said second clutch means comprises cooperating clutch surfaces on said armature plate and said housing.
References Cited by the Examiner UNITED STATES PATENTS 766,991 8/1904 Churchward 31812 2,615,148 10/1952 Critoph 318--12 2,686,894 8/ 1954 Mathieu 318-467 2,712,106 6/1955 Williams 318467 3,028,534 4/1962 Chilton 31828 ORI'S L, RADER, Primary Examiner. B. DOBECK, Assistant Examiner.