US 3184560 A
Description (OCR text may contain errors)
y 1965 P. R- PITTMAN, JR
DELAY T'IMER 2 Sheets-Sheet 1 Filed April 19, 1962 INVENTOR- PAUL R. PITTMAN JR. BY 71% yW ATTORNEY May 18, 1965 P. R. PITTMAN, JR
DELAY TIMER 2 Sheets-Sheet 2 Filed April 19 1962 INVENTOR. PAUL R PITTMAN JR.
ATTORNEY United States Patent 3,184,560 DELAY TEMER Paul R. Pittman, ha, Ear ten, (lino, assignor to Giohe Industries, inc, Dayton, Ulric, a corporation of (ihio Filed Apr. W, 1962, Ser. No. l fidii Claims. (fill. Mitt-$8) switch which is of light weight and small dimension, and
thus suitable for mounting on the instrument panel of an aircraft. A further object is to provide a time delay switch which is extremely accurate in repeatedly operating its actuating mechanism at the exact interval preselected. A still further object of the invention is to provide in a time delay switch employing a miniature motor, a simple but exact timing means for insuring constant output speed of such motor.
These and other objects of the invention will become more readily apparent upon a reading of the description following hereinafter and upon reference to the drawings, in which:
FIGURE 1 is an exploded perspective view of the time delay switch of the invention,
FIGURE 2 is a cross-sectional view through the assembled time delay switch of the invention,
FIGURES 3 and 4 are cross-sectional views taken along respective lines 33 and 4-4 of FIGURE 2, and
FTGURE 5 is a schematic line diagram illustrating the operative circuitry of the invention.
In the time delay switch of the invention an interval selection dial 62 is manipulated to select a time interval or switch position.
Briefly stated, the device operates as follows: When power is turned on, the motor 40 rotates and drives an escapement' 18. The escapement 18 controls the output speed or rotational speed of the motor output shaft 42. When power is applied to a clutch 12t32, this output shaft 42 is then coupled to a cam shaft 1% and the timing sequence commences. After the cam shaft has been rotated for the selected timing interval, it will be positioned so as to actuate switch actuating members and switches, which will accomplish the purpose of providing an output signal and shutting off the motor.
As indicated in FIGURE 1, the time delay switch 1 of the invention comprises a housing or cover 2 in the form of a can, and a second end housing 4, for the terminal board mounting which is assembled to the housing 2 by screw fasteners 5 to enclose the unit. The remaining enclosure is formed by the mounting plate 6 to which the cover 2 is sealed. Affixed to the mounting frame or plate 6 as by the screw fastenings 8 is the main frame it). Afiixcd to the main frame lil as by screw fastening 12 is the mounting plate ltd, which has attached thereto as by the fastening To an escapemcnt iechanism 13. Such escapement mechanism is not disclosed in detail herein since it is deemed to be wellknown in the art. Escapements which may be used can be of the lunghans type.
Also afixed to themounting plate 14 by a series of spacer sleeves such as 22, and the long screw or bolt 24, is a mounting plate 23. This mounting plate 23 serves as a means for positioning the "arious components, and also provides a means for mounting the terminal board 30 as by the fasteners 32 and 34-, thereto.
A motor 4d having an output shaft 42, which is splined "ice at its end as at dd, is mounted through the mounting plate M- and affixed to a hub 46 on such mounting plate.
The main frame it) has a forwardly extending hub 59 which forms a housing for a pair of bearing means 52 and These bearing means journal the main shaft 5'6. The shaft 56 has fixedly mounted at one end a detent plate 58, and is provided at the other end with a flatted reduced portion 60. A dial 62 is mounted on the tiatted portion 6-9 of the shaft 56 by means of a set screw 64 which passes through the dial 62 and through a hub 66, to bear against the fiatted portion 6%).
Mounted on the inner surface of the main frame iltl is a switch 7t) which is insulated from the frame by an insulator '72. The switch 7%) serves to actuate a relay '74- which is mounted to the mounting plate 28. The means for actuating this switch 7d includes a detent lever '75 which is afiixed to a mounting block 76 and which is urged towards the actuating button of the switch '70 by a detent spring 78. The spring '78 is also mounted to the mounting block 76. The mounting block, in turn, is aihxed to the front wall of the main frame 18. The detent spring has formed centrally thereof a series of teeth 8t} which cooperate with a series of teeth 82 on the detent plate 58. The teeth 3t? ride between the teeth of the plate 53, and when the shaft 56 is rotated, toe detent lever is raised to actuate the switch 70; an a tuating screw or knob 84 being employed for that purpose, which cooperates with the switch button 86.
The detent plate 58 is also provided with the stop pin 9% (see also FIGURE 3) which cooperates with the mounting block 76 to provide a positive mechanical stop for the rotational positioning of the dial d2.
Mounted on the outer side of the detent plate 53 are a pair of switches 92 and 94 (see FIGURES 1 and 4-). These switches serve to produce an output signal and cut off power to the motor, respectively, when the driving sequence has been completed. FIGURE 4 illustrates the relationship of the switches with respect to the cam shaft ltlti. The switches 92 and 94 are insulated from the detent plate 58 by insulating pads such as 98. Fastening means M92 are provided for mounting these switches to the plate. An actuator ltid is provided with a pivotal mounting hinge 1% to cooperate with the mounting bracket Hi7. The end we of the actuator 194 is positioned to contact the cam shaft i955, so that actuator 1M can actuate the switch button lid on the switch 92. The switch is so mounted that its actuating button 112. is directly actuated by the cam shaft 11%.
The clutching mechanism comprises an eiectrornagnetic core 129 which has mounted thereon the solenoid coil 122. A solenoid sleeve is fitted within the solenoid coil 122 and the solenoid plunger 126 is caused to reciprocate upon transmission of power to coil 1122. A housing fh, together with the end plate 132 serves to complete the clutch unit. Upon actuation of the clutch the solenoid plunger 12% is pulled to the left as viewed in FIGURE 2. The solenoid plunger 126 has threadedly fastened to it an actuating rod 134 which is also threaded at its outer end as at lid-6. The threaded portion 136 serves, by means of the fastenings 13S and Mil, to capture an actuating plate 142. The other end of the actuating plate is yieldably mounted on a stud 193i being urged to the right, as viewed in FIGURE 2, by the spring 152. A nut 15d serves to adjustably and fixedly position the stud 156- within the threaded hole 156. Thus, the mounting of the end of plate 14-2 on the stud i serves as a pivotal mounting to permit the actuating plate 142 to move to the left, as viewed in PTGURE 2, and thereby cause engagement of the clutching mechanism as described hereinafter.
The escapement drive shaft 116% has a spur gear 162 mounted thereon which mates with the appropriate gearing 164 within the escapement 18. As indicated in FIG- DRE 2, the drive shaft tee is mounted through a bearing 170 in the mounting plate 1'72. The actuating lever 142 is provided with an opening 143 to permit the mounting thereof about the cam shaft 198. The cam shaft 1% is a hollow shaft which is rotatably mounted upon the drive shaft 160. The end of the drive shaft 16d is reduced into a tenon portion 163 which pilots within the shaft 56.
A bearing 1% and a washer 182 are mounted on the left side of the actuating lever 142, so that when the lower end of the actuating lever 1 22 is drawn to the left, as viewed in FIGURE 2, the bearing 18% and the washer 182 are brought into engagement with a shoulder 1% on the cam shaft 108 which is integral with the clutch plate 192. The clutch plate 192 may be provided with a clutch facing 194, and the spur gear may be provided with a clutch facing 195, if desired (see FIGURE 2). Upon actuating the solenoid the clutch face TA I- engages the clutch facing 1%. Since the spur gear 1% is being driven by the motor it), the cam shaft 303 will commence rotation. Rotation of the cam shaft 5.38 will cause the winding up of the spring 1%. The spring 1% is afixed at its inner end to the shoulder 193 on the cam shaft 1% and is anchored at its outer end on a stud (not shown) mounted on the frame lli). When the cam shaft has been driven so as to actuate the switches, and thereafter power is cut off to the solenoid, the clutch is released and the torsion spring 19% returns the clutch plate 192 to its home position. This home position is arrived at by a lug 196 protruding from the clutch plate 192 which hits up against a stop screw 398 athxed to a block 2% on the mounting plate 1.
The spline 44 of the motor shaft 42 meshes with the spur gear 196 which is in turn affixed to the escapement drive shaft 161), so that the gear 162 both drives the escapement, and is controlled in its rotation by the escapement.
It is thus seen that in the time delay switch of the invention, a motor is combined with an escapement wherein the motor and escapement are geared to a common drive shaft which, in turn, is clutched to a cam shaft to actuate switches. With reference now to the schematic wiring diagram of FIGURE 5, it is seen that when the external start switch 3% is closed, plus power is transmitted through line 3%, the relay contacts 369d, 3%, switch 94 and line 3&5 to the motor 40. At the same time, power flows from relay switch contact 304, through line 303 to the clutch coil 122, to permit transfer of power by clutch actuation to the cam shaft. When the cam shaft 108 has been rotated for the preset time delay, the switch 94 is operated to open position, and the switch 92 is operated to closed position. When switch 92 is engaged, a signal will appear at the output terminal 316 since the power flowing through line 3&2 and switch contacts 304., 3% will pass through the switch 92 to the output terminal 314 At the same time that this occurs, the motor 4t will be stopped, since no power will be transmitted through line 305 to the motor. However, power still flows through line 3% so that the clutch remains engaged and the torsion spring remains wound up. To reset the mechanism, the start switch 3% is opened to remove power from line 3% and the clutch coil 122, so that the unit is re-zeroed.
In the event the control or time interval selector knob 62 is accidentally moved during the timing cycle, the switch 7th is momentarily actuated from its position engaging its contact 312 to the position engaging the contact 314. When the contact 314 is engaged, the plus power in line M2 will be transmitted to the relay coil 3% to actuate the relay and pull down the switch arm 304 from its position in contact with the contact 3%, to one where it contacts the contact 318. The relay switch '74 will remain in this position regardless of whether switch '79 returns to its normally open position or stays closed. With the contact switch arm 3% engaging the contact 318, power will be removed from both the clutch coil 1'22, i.e., line 3%, and the motor 40, i.e., line 305. In order thereafter to reactivate the unit, the start switch 3% must be reopened so that it can deactivate the relay 'id. The resistor is an arc suppression resistor and the network 322 is employed to provide damping to the motor, so that when power is removed the motor will immediately be stopped.
The delay timer of the invention operates as follows: The timing interval desired is first set by rotating the knob 62 which in turn rotates shaft 56 and positions the detent plate 58. Positioning of the detent plate changes the relative position of switches 2 and 94 with respect to their switch actuators. The setting of switch 92 determines the time interval between power-on until signal output; and the setting of switch 94 determines the time of power cut-off to the motor (which as indicated in FIG. 4 will always be immediately following the signal output).
When the switch 3% is operated to turn power on, both the motor 40 and the coil 122 are actuated. When coil 122 is actuated it moves the plunger 126 to the left as viewed in FIG. 2; and thus also moves the actuating rod 134 and actuating plate 142 to the left as viewed in FIG. 2. Operation of the actuating plate causes engagement of the clutch by moving the bearing and washer 182 into engagement with the surface 193 on the clutch plate 192. This causes the bringing together of the clutch faces 194 on the shaft 198 and 195 on the gear 1%; thus commencing rotation of the cam shaft 108. Actuation of the motor causes rotation of the motor shaft 4-2 and consequent rotation of the spur gear 1%, with which the spiined portion 44 of shaft 42 is in mesh. However, since the gear 1% is also afiixed to the escapement drive shaft 166, the gear 162 both drives the escapement and also is itself controlled in its rotation by the escapement. The escapement therefor acts as a speed limiter for the motor drive; and by this unique closed mechanical loop action insures extremely accurate timing intervals. Rotation of the cam shaft 108 for a sufficient interval will cause actuation of the switches 92 and d4 as above indicated.
Although a specific embodiment of the invention has been shown and described, it is readily understood that various modifications and rearrangement of the parts may be made without departing from the spirit and scope of the invention as defined in the appended claims.
What I claim is:
1. Time delay means comprising, in combination:
an electric motor having an output shaft provided with a first drive means; an escapement drive shaft, 21 second drive means affixed to rotate with said drive shaft, said first and second drive means being in engagement with one another;
an escapement means driven by said second drive means whereby the drive shaft is permitted to rotate only at a precise constant speed;
an electric switch;
switch actuating means for operating said switch at the end of a preselected timing interval; and electromagnetic means for selectively coupling said drive shaft to said switch actuating means for operating same when said motor is activated.
2. The time delay means of claim 1 wherein said selective coupling means comprises an electromagnetic clutch means and said switch actuating means includes a cam shaft; said switch being so mounted as to be positionable at various relative timing positions with respect to said cam shaft; said cam shaft being rotated upon energization of the clutch means to operate said switch.
3. The time delay means of claim 1 including a second switch; an electrical circuit including said motor, first and secend switches and said electromagnetic means, said first switch being so interconnected as to disrupt power flow to said motor, and said second switch being so interconnected as to provide a power output signal.
4. The time delay means of claim 3 wherein said switches are so constructed and arranged that the switch actuating means first operates said first switch and thereafter said second switch.
5. The time delay means of claim 1 including means comprising a relay switch for disabling the power supply to said motor automatically in the event the preselected timing interval is changed after initial activation of said motor.
References Cited by the Examiner UNITED STATES PATENTS Kesses 200-35 Hathaway 200-35 Greenwald 200-33 X Estey 200-35 Denton 200-33 10 BERNARD A. GILHEANY, Primary Examiner.