US2130405A - Time delay apparatus - Google Patents

Description

Sept/20,1938. R. A. mmamfs y 2,130,405

TIME DELY )APPARATUS Filed Oct. l0, 1935 E Y BY* INVENTOR /-u. ATTORN E Patented Sept. 20, A1938 uru'rraor STATES TIME DELAY' APPARATUS Rufus A. Andrews, Mount Vernon, N. Y., assignor 4to Ward Leonard Electrlc'Oornpany', a corporation of New York Application octoberv 10,1935, semi No. 44,464

(ci. 1in- 1) This invention relates to electrically controlled apparatus applicable to various uses where after o`ne action occurs, such as the initial closing of a circuit, a predetermined time interval is to .'i elapse before some other function is to be performed, such as to close or open another electric circuit or any controlling circuit oi another device, or to actuate a movable arm, lever, plunger, or perform any desired operation. l0 One of the objects of the invention is to obtain an improved form of apparatus which will have a high degree of accuracy in thedetermination of the time interval and maintain the same time interval under repeated operations in long continued use'. Another object is to provide a device which will be independent of changes of temperature. Another object isA to obtain a practically instantaneous reset of thev device for repeated use as rapidly as desired. Another object is to produce a device which will be dependable with long'continued use and of simple and economical construction. Another object is to avoid'the uncertainty and inaccuracy of gearsthrown into and out of mesh, or the use of clutches and to avoid the excessive wear occasioned by use of such type of apparatus. Other objects and advantages of this invention will be understood from the following description and accompanying drawing illustrating a preferred embodiment thereof.

Fig. i is a plan view on the line I--l of Fig. 3;

Fig. 2 is a vertical'section on the line 2 2r of Fig. 1 with certain pa'rts moved to a different position;

Fig. 3 is a vertical section on the line 3 3 of mg. l:

Fig. 4 is a vertical section on the line l-I oi' Pig.' 2;

Fig. 5 is a front elevation ofthe front dial of the device; and

` Eg. 6 is a general diagrammatic representation of certain parts and connections.

The apparatus shown comprisesv two sheet metal plates-I andl la spaced apart and supported by cross rods 2. On the rear side of plate throughtheplaielandcarriesflxedtoitsinner' end" spur gear-4. This'gear drives 'alargar il gear! which is iournaled on a shaft l which is supported at its rear end in the plate I and at its front end in the middle inner portion of an adjustable knob 1. This knob is shown in the form of a hexagonal nut cooperating with the dial on the front plate. 'I'he knob is journale in the front plate Ia..

Mounted upon the shaft 6 is a differential gear vcomprising the beveled gears 8, 8a and Ib. The

gear 8o'. is fixed to the gear 5 and rotatable therewith on .the shaft 6. The gear l is rotatably mounted upon a pin 9 which radially passes through an enlarged portion I0 of the shaft i. The gear 8b is secured to a wheel II which is rotatably mounted upon the shaft l. This wheel serves as a brake wheel. The outer periphery of this wheel is milled and is adapted to be engaged by a brake lever for holding the same in fixed position when desired.

Fixed to the inner end of the knob l is a circular plate I2. 0n the inside of the plate I2 is ixed a housing I3 for a spiral spring I4 contained within it. The housing ls in the form of a disc with an inwardly'turned edge which extends over the spring. 'I'Vhe outer end of this spring is secured by a pin Ila to the plate I2 or to the iat portion of the housing I3. 'I'he other end e oi the spring Il is xed to a barrel I5 by the pin IIb. I'his barrel has a. disc portion which is rotatable 4on the shaft 6 and an inwardly turned cylindrical 'portion which has notches lia formed around its inner edge at regular intervals. A pin It has a threaded engagement with, and extendsradially through, the shaft 6 and is located within the barrel I5. The outer end of the pin It extends beyond the barrel through any desired one of the notches Ita. 'I'his pin serves to transmit the tension of the spring Il to the shaft 6, tending to always turn the shaft 6 in one direction of rotation. The series of notches IBa permits the tension of this spring to be increased or decreased by rotating the barrel I5 while holding the shaft 6 stationary to impose a desired tension upon the spring and then passing vthe pin It through one of the notches 'in the adjusted position and through the shaft I. Fixed to the plate I 2 and extending from the inner face thereof is a pin I1. 'I'his pin extends into the path of the pin I i where it projects beyond the barrel I5. When the knob 1, andv correspondingly the plate I2, is adjusted to a desired position, it similarly adjusts the position of the pin I1, which position limits the extent of movement of the pin .Il and the shaft l in one direction of rotation as actuated by the springA Il. Mounted on the rear of the support-v ing plate Ia is a strip or plate of sheet metal I3 secured at one end to the plate Ia by a screw |8a. The other end of this strip extends over the edge of the plate I2. A screw |81) passes through the plate Ia from the front and has a threaded engagement at its inner end with the strip I8 at a point between the plate I2 and the screw |8a. It is evident that when the screw |8b is tightened, it will clamp the plate I2 in any iixed adjusted'position. A pair of pins I9 extend from the inner face of the plate I2 and are located so that when the plate |2 is turned, one or the other of the pins I9 will engage the edge of the plate I8 and-thus serve as a stop to limit the extreme range of movement of the plate i2.

Fixed to the portion I0 of the shaft 6 is an arm 2U of insulating material, such as Bakelite, being secured to the shaft by a screw ct passing through an upturned end of the arm 29. The screw 2da may be extended to form the pin 9 as its opposite end, as shown in the drawing. The present application of theinvention is to the control of an electric circuit, and for this purpose the arm 2U carries at its outer end a cross piece 2i of metal having a pair of contacts 2in at its opposite ends on its inner face. These contacts are adapted to engage with a corresponding pair of fixed contacts 22a supported in a fixed position by metal strips 22 mounted on an insulating cross bar or. plate 23 supported by and extending between the plates l and ia. The conducting strips 22 are provided with holes 22h at their outer ends for connection to any external circuit to be controlled.

In the path of the end of the arm 20 and between and below the xed conducting strips 22, is movably mounted a conducting stripl 24 which passes through a small opening in the insulating plate 23 and is then bent at right angles and extends downwardly, as shown in Fig. 3. The inner face of the lower end of the strip 24 carries a contact 24a. This contact is adapted to engage a fixed contact 25 mounted on the plate 23 opposite the contact 24a. A pin 26 extends freely through the downwardly extending portion of the strip 24 and extends also through the plate 23. The pin 2G is headed at its inner end to prevent the pin from passing through the plate 23 when the pin is forced outwardly. On the outer end of the pin 26 is a disc 26a having an inwardly turned edge, and a similar disc 2Gb surrounds the pin 26 and is located at the front of the downwardly extending portion of the conducting strip 24. A spring 21 encircles the pin 25 and extends between the discs 26a and 2Gb. This spring tends to force the pin 25 outwardly, the disc 25a. being prevented from outward movement by a pin 25e passing through lthe outer end of the pin 2E. Normally the spring 21 thus tends to force the downwardly extending portion of the conducting strip 24'inwardly so as to cause contact 24a to bein engagement with fixed contact 25. If,A however, the inwardly extending end of the strip 24 be depressed, the downwardly extending portion of the strip 24 will be moved outwardly against .the pressure oi the spring 21 and the circuit will be opened between the contacts 24a and 25. The strip 24 is electrically connected by a lead 24h which is soldered thereto, to one lead of the electric driving motor 3; and the'contact 25 is connected by a lead 25a to one side of the supply circuit of the motor. Thus when the contacts 24a and 25 are in engagement, the motor circuit will be closed provided the motor circuit is othervpassing loosely through the strip 2|.

wise closed; but when the inner end of the strip 24 is depressed, the motor` circuit will be open.

The inner end of the strip 24 is in the path of movement of the arm 20; and when this arm is driven to its final position by the motor 3, it engages the inwardly projecting end of the strip 24 and depressesit to openthe contacts 24a and 25, thus opening the motor circuit kat the completion of 'its function. The arm 20, in moving to its limiting position, causes the cross strip 2| carried by the arm to engage the fixed contacts 22a before the stripv 24 is engaged by the arm 20. In order to .permit the arm 20 to continue its movement toengage the inner end of the strip 24, the cross strip 2| is yleldably mounted on the top of the arm 20 by a pin 28 fixed to the arm 20 and Between the strip 2| and a disc 29 retained in place by a pin 28a passing through the outer end of the pin 28, is located a spiral spring 30 which surrounds .the pin 28. Thus this spring tends to normally hold the cross piece 2| against the arm 2l).

When, however, the cross piece 2| is swung over by the arm 2|! to engage the contacts 22a, 4the cross strip 2| is permitted to yield and move up wardly on the pin 28 while still maintaining engagement with the contacts 22a. This permits the arm 20 to continue its movement suiiiciently to engage the inner end of the strip 24 and open the circuit of the motor, as already described.

The brake for holding the brake wheel in xed position when desired is actuated by an electromagnet 3| mounted on an inwardly extending portion Ib of the plate I. A strip 3|a of magnetic material extends from the lower end of the core of the magnet 3| upwardly at the side of the coil of the magnet. Movably mounted on the upwardly kextending end of the magnetic strip :ila` is an armature 3Ib which extends over the upper end of the core of the magnet 3|. A strip 32 is secured to one end of the armature 3|b and has an extension 32a therefrom. A spring 33 is connected at one end to this extension and at the other endto an extension 34a from a strip 34 clamped between the lower portion of the mag- A rod 35 passes loosely through the projecting end of the strip 35 and a pin 36a is passed vthrough the upper end of the rod 36'above the strip 35 for supporting the end of the rod by the strip. The lower end of the 'rod passesl loosely through the brake bar 31. This bar extends' over the brake wheel I I and is pivotally mounted at the opposite end from the connection of the rod 35 on a pin 33 projecting from and supported by the plate Ia. lThe brake bar is supported in relation to the brake wheel so that when the bar is forced downwardly by the rod 36 it will press against the brake wheel and thus hold the wheel in fixed position. At the upper end of the rod 3B is a spiral spring 38h which encircles the rod. The upper end of the spring is seated in a shallow metal cup 35e located on the lower side of the extended portion ci strip 35. The lower end of the spring is seated in a similar cup 36d which is retained from downward movement on the rod by a pin 36e passing through the rod.

When' the amature SIb is attracted by the controlling magnet 3|, the strip Il will `cause a downward movement of the rod by the strip being forced downwardly against the spring which in turn exerts a downward pressure on the pin "e and thus causes a downward. movement of the rod. Before the amature of the magnet has completed its movement to 'its nal vattracted podtion, the brake bar will engage the circumference of the brake wheel I I; and in the further movement of the amature. the spring b will be somewhat compressed. 'I'his insures the application of a predetermined and sufilcient pres'- sure of the brake bar 31 against the brake wheel.

Fig. 6 shows the connections of the parts, there being a main closing switch V39 between the source Il and the controlling apparatus. The magnet II is connected acro the supply wires so as to be controlled by the switch 3l and also when desired by switch 4I in the magnet circuit for controlling this circuit independently of the motor circuit. The electric motor is connected across the supply wires through the switch 24 when engaging the contact 2B and this switch is beyond the connections of the magnet Il so that whenthe strip or switch 24 is opened, it will not open the circuit of the magnet 3|. Another switch 42 -is shown in series in the motor circuit which may be used when desired for controlling the motor circuit independently of the magnet circuit.

On the face of the plate Ia is mounted a dial plate having a circular scale o concentric with the aids of the knob 1. Thisscale may be graduated in seconds or any other time intervals desired, depending upon the design and purpose -of the apparatus. An arrow 1a is marked on the face of the knob 1 to cooperate with the scale for securing any desired time interval setting. f

In operation, the screw IIb will be loosened for permitting adjustment of the plate I! to attain any predetermined time interval of operation by turning the knob 1 to the proper setting. The screw IIb is then tightened to hold the plate I2 in fixed position. In making this setting, the pin I1 has been adjusted to a certain position which, by its engagement with the pin III, causes the shaft 6 ofthe mechanism to assume `a certain initial position. The' initial position of the `shaft will always correspond to the adjusted position of the pin I1 because' the spring Il always tends to actuate the shaft and the pin It in a direction to cause the latter to engage the pin I1. In making this adjustment of the initial position of the shaft 0 it necessarily follows that the control arm 20 is moved by the shaft to assume its initial position at some point which is at a predetermined angular position from the fixed contacts 22a. In Fig. 1 the arm 20 is shown at about 180 from-a plane passing Athrough the contacts 22a and through the axis switch Il. 'I'he contact strip 2l is then in en- Agage'ment with the xed contact 2l by reason of being closed by the action of spring 21 as already described. The clodng of the line switch l! energiaes the magnet SI which attracts its armature IIb downwardly and moves the brake bar I1- downwa'rdly to engage and hold brake wheel II in fixed position as already explained. The closing of the line switch also starts the motor to drive the gear 8a in one direction of rotation. In view of the brake wheel II and its bevel gear Ib being held in fixed position at this time, the rotation of the gear la will cause the rotation of the gear l on its pin support. On account of the gear Ib being held stationary, it results that the shaft 6 is turned by the gear 8 being forced to travel around the gear lb. The direction of rotation ofthe gear la is such as to cause the shaft I and-its arm Ilto be moved in a direction to approach the flx'ed contacts 22a. The driving movement continues resulting in the t cross piece 2| first engaging the contacts 22a and then, as already explained, causing the arm 2l to engage the contact strip 2l and open the circuit oi' the motor. This stops the motor and prevents any further supply of energy thereto. The arm 2l and the differential gear remain in their final position, however, because the magnet 3i continues to be excited holding the gear Ib in position. 'I'he bevel gear la also remains in fixed position because friction and the trains of reduction gearing prevent the motor from movement.

After the movement of the controlling arm 20 has accomplished its purpose the line switch 39 may be opened. The controlling arm 2li will then immediately snap back to its initial position because the release of the brake wheel II by the magnet permits this wheel to revolve freely and the spring I 4 which is always exerting its tension on the shaft is permitted to act to rotate the shaft I. The rotation of this shaft by the spring causes the differential gear 8k to travel back around stationary gear la, permitting the return of the parts to their initial positions. Upon again closing the line switch 3l, the operation may be repeated in the manner just described and this repetition may occur as often as desired. l

It is evident that by reason of the motor I, being a synchronous motor and by reason of the frequency of theusual alternating current supply lines being kept substantially constant, the time required for the motor to drive the parts from their initial position to their final position, will always be substantially the same. If it be desired that the time interval between the closing of the line switch 3S and the attainment of the final position of the arm 20 be changed to any other desired time interval, the knob 1 will be ad- .iusted in the-manner already described to give the desired time interval by a proper new location of the pin I1. Thus, a wide range of predetermined time intervals may be obtained by a simpleand /conven'ient adjustment.

'I'he adjusted tension of the spring I 4 does not affect the time interval of the sequence of operations because that is determined by the constant speed of the driving motor. The tension of the spring Il does affect the time of snapping the parts back to their initial position and this ten# sion may be such as to make the return of the parts substantially instantaneous. 'Ihe apparatus is not subject to any material wear under; long continued use because as regards the brake,

there is no appreciable friction wear vbecause the l brake bar engages the brake wheel quickly before there is any appreciable torque exerted by this wheel; and as regards the gearing there is no appreciable wear because Athe gearsare always in mesh and there is vno shifting of the parts or uncertainty of engagementof shiftable parts.

. In some applications of the invention the motor 3 maybe started before the circuit of the brake magnet is closed. In such a case the switch Il will first be opened and the motor started by closing the switch I2, assuming the line circuit fto be closed. With the magnet circuit open and .the motor running, the control arm 2l remains in its initial position and the bevel gear 8b and brakewheel are loosely driven in a direction reverse to that o! gear 8a. Upon closing switch 14| the brake wheel and gear 8b' are held in xed position and the operation of the parts occurs in the manner already described, the time delay interval elapsing after the closing of switch 4i. Upon again opening brake magnet switch 4|, the control arm 2li will automatically be returned to its initial position, even though the motor resumes its rotation upon the automatic closing of contact strip 24, as the brake wheel is then tree to turn idly. indeed the motor circuit may re main closed continuously and the time delay action initiated by the closing of brake magnet cir1 cuit and obtaining reset by opening the brake magnet circuit.

In some cases, instead ci using an alternating current synchronous motor, a constant speed direct current motor may be used supplied from a circuit of substantially constant voltage; and it will be understood that various modifications and various applications of this invention may be made without departing from the scope thereof.

I claim:

1. Time delay apparatus comprising a driven element to be moved from an initial position to a final position, a circuit to be controlled, differential gearing for driving said element, an electric motor for driving said gearing in one direction, electromagnetic means for controlling the movement of one of the gears of said gearing,

a switch for closing thecircult of said means, a switch for closing the circuit of said motor biased to closed position, means successively engaged by said driven element and controlled thereby for first ail'ecting the connections of said circuit to be controlled and then opening said second named switch upon said element attaining its final position, and a spring for returning said element to its initial position upon the subsequent opening of said first named switch.

2. Time delay apparatus comprising a driven element to be moved from an initial position to a final positon, a. circuit to be controlled, differentialv gearing for driving said element, an electric motor for driving said gearing in one direction, electromagnetic means for holding stationary one of the gears of said gearing, a switch for closing the circuit of said motor and of said means, a switch for closing the circuit of said motor biased to closed position, means successively en- Haged by said driven element and controlled thereby for rst affecting the connections of said l circuit to be controlled and then actuating said Second named switch for opening thecircuit of the motor upon said element attaining its final position, and a spring for returning said element to its initial position upon the subsequent opening of said first named switch.

3. Time delay apparatus comprising a driven element to be moved from an initial position to a iinal positon, diilerential gearing for driving said element, an electric motor for driving said gearing, means comprising a. magnet for holding stationary one of the gears of said gearing, means for closing the circuit of said motor and of said magnet, circuit controlling means actuated by said element upon its attaining a certain position,

a spring for returning said element to its initial position upon opening the circuit of said magnet, a projecting element movable with said driven element, a stop engaged by said projecting eienient for limiting the initiai position of said driven element, and movable means for adjusting the position of said stop, said spring having one end thereof mechanically connected with said movable means.

4. Time delay apparatus comprising a driven element to be moved from an initial position to a flnai position, diierential gearing for driving said eiement, an electric motor for driving said gearing, means comprising a magnet for holding stationary one of the gears of said gearing, means for ciosing the circuit of said motor and of said 130 magnet, circuit controlling means actuated by said element upon its attaining a certain position, a spring for returning said element to its initial position upon opening the circuit of said magnet, a projecting element movable with said driven element, a stop engaged by said projecting element for limiting the initial position of said driven element, and means for adjustably connecting one end of said spring to said projecting element.

5. Time delay apparatus A4comprising a driven element to be moved from an initial position to a final position, differential gearing for driving said element, an electric motor for driving said gearing, means comprising a magnet for holding driven element, movable means for adjusting the position of said stop, said spring having one end thereof mechanically connected with said movable/means, and means for adjustably connecting the other end of said spring to said projecting element.

RUFUS A. ANDREWS.

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