US2507989A - Timing device - Google Patents

Description

May 16, 1950 J. F. MERKEL 2,507,989

TIMING DEVICE Filed Aug. 6, 1947 2 Sheets-Sheet 1 Y I? F .1. 0 K 14 fl g IG: R6 45 a1. 1O

31 16 i H i! 30 a la 26 2Q 18 i5 19 1 1 y 16, 1950 J. F. MERKEL 2,507,989

TIMING DEVICE Filed Aug. 6, 1947 2 Sheets-Sheet 2 .J O a: P- 5 0% 5 UJQ tau 3:95 P- OD F fi 9 LL N h n w (I) Q- Q '0 5 o H 01 8 m h 3+ o m r "1 m w LO O H O m O o In 1; Q :2 NM 0 w l\ m 0 0 {Q o 4/ g o I fit; lg a") Q g Zhmeutoz Patented May 16, 1950 TIMING DEVICE Joseph F. Merkcl, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application August 6, 1947, Serial No. 766,615

Claims.

This invention relates to timing devices and it more particularly pertains to improvements in timing devices actuated by a constant speed motor.

. There are certain applications, particularly in railway signaling, where a time interval of substantial duration must be accurately and dependably measured. For example, it may be desired to impose a retricted signal penalty on a train unless the train consumes a certain amount of time within a particular predetermined distance. The timing in this case is indicative of the maximum speed the train may travel without penalty, and a high degree of accuracy in timing is required. It is also required that the timing device after having been used to time the passage of one train must be quickly restored to condition it for timing the next train, thus .preventing a following train from gaining advantage of timing which has been efiected by a train in advance.

- An object of the present invention is to provide an improved, economical, rugged, and dependable timing device to meet the above requirements.

- Another object of the present invention is to render the timing device responsive .to alternating current input, such input being effective to energize a synchronous motor which is effective to drive a mechanical timing mechanism through a direct current magnetic clutch energized from the alternating current input through a suitable rectifier unit.

objectin the use of the magnetic clutch is to allow the mechanical timing mechanism to be restored by gravity upon removal of input energy to the timing device, without having to drive the synchronous motor backwards through reduction gearing and without requiring the disengagement of any gears.

Another object in the use of a magnetic clutch is to improve the accuracy of the timin device upon initiation as compared to the accuracy of timing devices in which the engagement of gearing at the initiation of the devices may gain or lose time dependent upon the relative positions of the gears when they are brought into mesh. Themagnetic clutch also has the advantage of being less susceptible to wear than small gear-' ing that must be intermittently engaged and disengaged. Y

1 Another object of the present invention is to provide a primary-secondary timing device organization whereinthe direct current magnetic clutch and a secondary relay are operated from the alternating current input to the device through a step down transformer and rectifier; wherein the secondary relay is energized in response to closing of contacts of the timing I mechanism; wherein the secondary relay in response to its energization tie-energizes the motor and the magnetic clutch; and wherein the direct current secondary relay is maintained energized bya stick circuit dependent upon input alternating current to the timing device.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description progresses.

In describing the invention in detail, reference is made to the accompanying drawings in which similar reference characters are used to designate corresponding and similar parts in the respective views; and in which:

Fig. l is an elevational view shown partly in cross section of the principal operating parts of the timing device of an embodiment of the present invention;

Fig. 2 is an end elevational view of a portion of the timing device showing particularly the mechanically actuated timing contacts; and,

Fig. 3 shows in perspective the principal oper-. ating elements of the timing device according to the present invention with certain parts being shown in cross section or in expanded relationship for the purpose of facilitating the disclosure. Fig. 3 also shows schematically the circuit organization for the control or respective elements of the timing device.

With reference to Fig. 3, a conventional syn-, chronous motor SM is provided with a suitable reduction gearing RG the output of which is applied to the pinion H] which drives through a suitable gear II the drive shaft l2 extending center for passage of the shaft [2. The assembly of the winding within the case C is accomplished by the insertion of the winding over the core and against a suitable washer I6 whereby the pole piece I! at the left-hand end of the core l draws the winding l3 tightly within the casing C when the core I5 is threaded into the end plate M of the case 0.

With reference to Fig. 1, suitable bearing inserts l8 and i9 at the respective leftand right hand ends of the core l5 are provided for journaling the drive shaft |2 which is preferably of non-magnetic material. The short portion 26 of the shaft |2 extending immediately to the left of the bearing I8 is squared, or otherwise formed to accommodate the drive disc 2| so as to cause that disc to be rotated by the drive shaft i2. The drive disc 2| is preferably of nonmagnetic material and is formed as shown in Fig. 1 with its center area having a reduced cross section to allow space for the dished spring 22 which is assembled on the drive shaft l2 at the left of the drive disc 2| to bias the clutch MC to a disengaged position.

The driven mechanism of the clutch MO is rotated by the motor SM only when the clutch MC is energized, and its parts are free to slide longitudinally and rotate about the driven shaft l2.

The driven disc 23 is suitably secured as by riveting at the point 24 to a squared portion of the hub 25 which is slidably fitted on the lefthand end of the drive shaft l2, such hub being formed with longitudinally spaced bearing ends for rigidly supporting the driven disc 23 concentric with the drive shaft i2. The hub 25 when assembled on the left hand end of the drive shaft I2 is spaced by the washer 26 from the dished spring 22.

The'driven disc 23 has a reduced cross section area near its center as it is only desired to use the outer surface 21 as a clutch face. The disc 23 has secured therein the contact pins 28 which extend slightly beyond the right-hand surface 29 of the driven disc 23, and it is thus these contact pins 28, because of their friction against the drive plate 2|, that provides the operable connection between the drive and the driven discs 2! and 23 respectively. It has been found that three of these pins 28 are sufficient when they are spaced substantially 120 apart about the surface 29 of the driven disc 23.

The pinion gear 30 is slidably fitted over the hub 25, and the right-hand end of the gear 30 is squared so as to be rotatably secured to the washer 3|. The washer 3| is biased against the driven disc 23, through the pinion gear 36, by the coil spring 32 at the left-hand end of the pinion gear 30. The spring 32 is assembled over the hub 25, and is maintained under tension by the washer 33 which is also assembled on the left-hand end of the hub 25 and is held in position by the key 34 that is fitted into a suitable slot near the left-hand end of the hub 25. The lock nuts 35 are threaded onto the end of the drive shaft l2 against the left-hand end of the hub 25 to maintain the spring, 22 under compression, and to maintain the desired normal clearance between the pins 28 of the driven disc 23 and the contact surface 36 of the drive disc 2|.

By this structure of the driven mechanism of the clutch MC, it is provided that the driven disc 23 and pinion 30 organization is free to rotate about the drive shaft I2 when the magnet is deenergized, and the structure further provides that the gear 30 can be rotated with respect to the driven disc 23 by slippage between the washer 3| and the contact surface 21 of the 4 driven disc 23 for purposes to be hereinafter considered.

The gear 3!] drives a vertically disposed toothed rack 31 of a time contactor mechanism. The rack 31 is substantially square in cross section and it is maintained in lateral alignment with its teeth engaged in mesh with the pinion gear 30 by the roller 38 which is engaged in a longitudinal slot 39 on the opposite side of the rack 31 from the teeth 46. The roller 38 is suitably secured as by the pin 4| within a bracket 42 which is held in alignment and secured to the fixed supporting bracket 43 by the pin 44 and the screw 4.5.

Secured to the lower end of the rack 31 is a double break contact member comprising a plate 46 of good conducting material extending across the lower end of the rack 31. At each end of the plate 46 front contact points 41 are secured to its upper surface and back contact points 48 are secured to its lower surface. The front contact points 41 which are secured to the upper surface of the contact plate 46 are preferably of silver impregnated carbon which are suitably secured to the contact plate 46 as by the contact sleeves 49 of copper or other low resistant material. The contact sleeves 49 have ears 50 ex tending through the contact plate 46 and suitably secured thereto as by solder. The back contact points 48 are secured as by solder to the lower side of the plate 46 and they are of low resistant material such as silver or tungsten, although it is to be understood that contact points of other materials could as well be used if required in practice.

The contact plate 46 is .secured to the lower end of the rack 31, so as to be insulated from the rack 31, by the screw 5| which extends through upper and lower insulation blocks 52 and .53 and through the insulating sleeve 54 which insulates the threads of the screw 5| when passing through the contact plate 46. The upper block 52 of insulating material maintains the contact strip in alignment with the rack by the detents 55 and 56 which engage in recesses in the rack 31 and contact plate 46 respectively. The screw 5| is locked in its tightened position by the transverse pin 51. The contact plate 46 is notched at the point 58 as more clearly illustrated in Fig. 3 to allow clearance for the supporting rod 59.

The contact fingers BHand 6| of the adjustable member AC are spaced on opposite sides of the rack 31 and so disposed so as to cooperate with the double break contact points 41 so as to close a circuit between the fingers 68 and 6| when actuation of the timing device is complete.

The contact fingers 66 and 6|, together with their respective supporting fingers 82 and 63, are suitably secured to the transverse plate 64 of insulating material as by the screws 65 which extend through longitudinal metal brackets 66 on the opposite sides of the rack 31, such screws being insulated by suitable bushings (not shown) and by insulation plates 61 from such brackets 66. Disposed between the brackets 66 are two pairs of rollers 68 and 69 bearing against the respective front and back sides of the rack 31. The rollers 68 and 69 are pivoted by the pins 10 which extend between the brackets 66, and they are provided with suitable spacers 1| for maintaining the rollers close to the edges of the respective sides of the rack 31 with which they are associated. Thus on the toothed side of the rack 31 one roller 68 rides against the rack 31 on each side of the teeth 40.- V

The adjustable contact carrying member AC is adjustable in that its elevational position is determined by the threaded rod 12 which is threaded through the hub 13, the hub 13 being suitably secured within the plate 64 of insulating material. It is thus provided that the turning of the threaded rod 12 as by the screw 14 through the bevel gears 15 and i6 is effective to drive the adjustable contact carrying member AC up and down the rack 3'! and thus vary the distance the rack 31 must travel before the double break contact points 41 at the lower end of the rack 31 close a circuit from contact finger 50 to contact finger 6|. The lower end of the threaded rod 12 is journaled in the fixed plate 11 at the base of the relay at the point 78 (see Fig. 2), and end play in the threaded rod 12 is taken up by the spring 19 acting against the washer 88 and the shoulder 81 of the threaded rod 12.

By the use of a fixed rod 59 extending from the point 82 (see Fig. 2) in the supporting bracket 43 to the point 83 in the base plate ll, extending through the slot 84 in the outer edge of the plate 85, the adjustable contact carrying member AC is maintained in alignment between two fixed points. With the rack 31 extending through the adjustable contact carrying member AC between the guide rollers 68 and 69 at the front and back of the rack 31, and between the brackets 66 at the sides of the rack 3'1, the adjustable contact carrying member AC serves as a lower bearing for the rack 31 to insure the contacts 60 and GI to be in accurate alignment at point of contact with the double break front contact points 4?.

Cooperating with the double break back contact points 48 at the lower side of the contact strip 46 are contact fingers 86 and 81 disposed on opposite sides of the rack 31. These contact fingers 86 and 81 together with supporting fingers 88 are suitably secured as by the rivets 89 to the block 90 of insulating material, which block 90 is suitably secured to the base plate 71 as by the rivets 9| as shown in Fig. 2. It is thus provided that an electrical connection is closed between the lower contact fingers 86 and 8'! only when the rack 31 is restored to its dropped away position as is illustrated in the accompanying drawings. The adjustment screw 92 and lock nut 93 in the base plate 11 serves to provide a stop for limiting the downward movement of the rack 31, rather than having the back contact fingers 86 and 81 absorb the entire shock when the rack 31 is released by the magnetic clutch MC.

Aside from the parts of the timing device that have been described, with reference to Fig. 3, the device includes a direct current secondary relay SR, a rectifier unit R, and a step down and insulating transformer T. The terminals 94 and 95 are the input terminals to the timing device, and the switch SW is to be understood as merely symbolic of any switch or any contact of any device which may be employed in practice to render the operation of the timing device effective.

Having thus considered the general organization and structure of the timing device according to the embodiment illustrated, consideration will now be given as to the mode of operation of the device under certain typical assumed operating conditions. To consider operation of the device, it will be assumed that the switch SW is closed to apply alternating current from a suitable source such as a 110 volt A.- C. supply, the symbols BX and CK being used to designate the respective instantaneous positive and negative terminals of such source of supply.

It is thus provided that the closing of the switch SW for eifecting operation of the timing device applies alternating current directly to the input terminals 94 and of the device. The application of energy to the input terminals 94 and 95 of the timing device energizes the primary winding 96 of the transformer T directly and also applies alternating current to the synchronous motor SM through the back contact 91 of the secondary relay SR. The input terminals of the rectifier unit R are directly connected to the secondary winding 98 of the transformer T, and

thus direct current is available at the output terminals of the rectifier R whenever alternating current energy is applied to the input terminals 94 and 95 of the timing device.

With direct current energy applied at the output terminals of the rectifier R, the winding l3 of the magnetic clutch becomes energized by a circuit extending from the positive terminal of the rectifier R including back contact 99 of relay SR, and winding I3 of the magnetic clutch M0, to the negative terminal of the rectifier R. The energization of the magnetic clutch MC sets up a magnetic field (see Fig. 1) in a magnetic circuit ex tending from the pole piece l1, through the disc 23, the case 0 and the core l5. It is preferable that the disc 2| be of non-magnetic material such, for example, as Phosphor bronze so that the sensitivity of the clutch is improved by the disc 23 providing the only path of low reluctance between the core I5 and the case 0, the disc 23, the core 15 and the case C all being of magnetic material such as silicon steel having relatively low reluctance. The setting up of the magnetic circuit as described thus acts upon the disc 23 to attract the disc against the bias of the spring 22, to cause the contact pins 28 to contact the surface 36 of the disc 2| and thereby cause rotation of the driven disc 23 to be effective in accordance with the rotation of the drive disc 21. The attraction of the disc 23 is such as to urge the pins 28 tightly against the disc 2| so as to prevent slippage and cause the rotation of the driven disc 23, and thus the driving of the pinion gear 30, to be in correspondence with the rotation of the drive disc 2|.

The direction of the drive of the gear 30 is counterclockwise as viewed in Fig. 2, and is necessarily at a constant rate of speed determined by the speed of the synchronous motor SM and its associated reduction gearing RG. The initial raising of the rack 31 is effective to open the double break contact connection between the back contact fingers 86 and 81, and thus open a check circuit which is usually employed in connection with the use of timing devices of this character to check that full restoration of the device is efiected after each operation.

The time consumed in the raising of the rack 31 before a circuit is closed between the contact fingers 69 and 6| of the adjustable contact member is dependent upon the adjusted elevational position of the adjustable contact member as is conveniently indicated by a suitable scale l 00 (see Fig. 2) which is secured as by the rivet HH to the rod 59. This scale is preferably graduated in seconds so disposed as to read opposite the contact fingers 69 and BI the number of seconds consumed in the raising of the rack 31 to the point where thecontact points; 41 close. a circuit between contact fingers .60 and .61.

The closing of a circuit between contact'cfingers.

60 and SI is effective to energize 'the secondary relay SRwith: direct; current .by. a circuit extending. .fromthev positive terminalof the rectifier R. and including contact. fingerlil, contactl'finger .60, and winding of relay. SR to the negative terminal of the rectifier R. -ThesecondaryrelaySR preferably-has its contact 9l :adjustedas. a .make-. before-break. contact. as illustrated. in order that the shifting of contact 99 upon theenergization of relay SR may close a stickicircuit at ..front contact 99 prior-ta tile. openingcofthe pick up energizing circuit that has just. been .described. It'is: thus provided-that the pickingup of the relay. SR is effective Icy-the closureof its front om tact -99 to shunt-the contact fingers 86 and. Bi out of its energizing circuit. and .thus...maintain...the secondary relay SR" in r itszenergized condition so long as alternating current is. applied to the input terminals 94 and 95 of thetiming device.

Theclosure of front contactslOZof secondary relay SR is efiective togovern any time control circuitin accordance with therequirements of. practicesucn, for example, asa circuit permitting-the clearing of asignalfor a train. It can thus be providedthat. the alternating. current Upon the picking up of the secondary'relay SR in response to the closure of. a circuit between the contact fingers 6B and. 6 I. of. the timing device.

thealternating current energy. isremoved from 2 the synchronous motor SM by .the. opening of 1 backcontact Bland the opening ofback contact 99' deenergizes thel.magnetic .clutch MC. Upon deenergization of..the magnetic clutch MC, the :disc -23. (see Fig.1) is restored to its lefthand position. by the spring 22 sov as to be dis, engaged from-the'drive disc 2|, andimmediately upon such restoration, the disc 23'. and Jthegear r 30 are allowed-to turn .free; on theidrive shaft !2. They are driven in a clockwise direction by the weight of the rack 31 until the rack 31 reaches its fully dropped away position. When the rack 31Ireaches its fully dropped-away position, the contact of the screw 5i with the stop 92 (see' Fig 2) bringsthe dropping away ,of therack 3l-to a'stop, and for purposes of preventing pose sible damage to the small teeth-of the gear 38 R, and thus the secondary relay SR is dropped away so as to open its stick circuit at front contact 99 and close back contact 99 to complete the conditioning of the timing device fora subsequent mode ofoperation upon again closing the switch 1 SW.

From the structure and mode of-operation-of the timing device as it has been described, lt-= will be apparent that the timing device has the advantageiof accuracy duecto use of a synchronous driven. motor; the problems of engagement and disengagement of the driving mechanisrn for. therack 3'! is solved in a manner by use 7 of the magneticclutch MC whereby no timeis lost orgained upon initiation of the device as is inherent by timing devices where the meshing otgears is required upon initiation of the device; theiuse of double break contact organizations accomplishes the control of circuits without re-- quiring wiring.connections to the movable contacttpoints associated with the rack 31; the magnetic clutch MC and the secondary relay SRoperate at their greatest efficiency because of being operated on direct current but yet require no source ofdirect current outside of the timing device; and-the dropping away of the rack 31 upon the-picking up of the secondaryrelay SR is effected without shock to the small teeth of the rack andpinion because of inertia of parts. of the magnetic clutch MC.

Having .thus described a specific timing vdevice. as one embodiment of the present inven-. tion it is to be understood that this form of the. invention has been selected principally to facilitate its disclosure and that various adaptations,

alterations, and modifications may be applied to the specific form shown to meet the requirements of practice withoutin any manner departing from the spirit or scope of the present invention-except as limited by the appending claims.

What I claim is:

1. In a timing device driven by aconsta-nt speed motor, :a contactor mechanism comprising, .an

elevationally disposed toothed rack driven by 1 said motor, adouble break contact member secured to" the lower end of said rack, said contact member having two laterally spaced contact" points, and-said contact points being electrically connected together, and an elevationally ad justable contact carrying member having two laterally spaced contact fingers insulated from each other, said fingers being so disposed as to co'operatewith said contaotpoints respectively whenxsaid rack is raised by said constant speed motor andsald adjustable contact carrying memher having a portion journaling said rack substantially at the elevational position where the points'of-said double break contact member contact said contact fingerswhen saidrack is raised by said motor, whereby the contact points are most accurately aligned with the contact fingers at 'thei'elevationally operated position of said rack where 'anaelectrical connection is closed from one-of said "contact fingers to the other by the double break contact member.

2. In a timing'device driven by a constant speed motor, a magnetic clutch having a drive disk ro tated by. said motor through reduction gearing and a driven disk of magnetic material normally biasedaway fromv said drive disk but attracted to it by the energization of the winding ofsaid clutch, a friction disk, a pinion gear driven by said driven disk through said friction disk, an

elevationallydisposed tooth rack engaging said pinion gear and operable between upper and lower limit positions, front and back contact points secured-to the lower end of said rack, an

elevationally adjustable contact finger closed with said frontpoint upon the raising of said rack,

7 afixed-contact'finger closed-with said back contact point only when said rack is in said lower limit position, and electro-responsive means responsive to the closure of said elevationally adjustable contact finger with said front point for deenergizing said magnetic clutch and permitting the restoration of said rack by gravity to its lower limit position, irrespective of said constant speed motor and said reduction gearing, whereby said rack is quickly restored by gravity to its lower limit position once operation of the timer has been completed to close a front contact, and whereby slippage between said friction disk and said driven disk when the rack reaches its lower limit position prevents the inertia of said driven disk from damaging the teeth of the rack.

3. A timer having input terminals to which alternating current is selectively applied for operation of the timer comprising, an alternating current constant speed motor, an elevationally disposed toothed rack having contact points secured thereto, a magnetic clutch coupling said motor with said rack only when said magnetic clutch is energized, a secondary relay, circuit means including said contact points for energizing said secondary relay when said rack is elevated by said motor to a predetermined elevationally adjustable position, stick circuit means for maintaining said secondary relay energized in accordance with the application of alternating current to said input terminals, clutch energization means including a rectifier for energizing said magnetic clutch from the alternating current applied to said input terminals, said clutch energization means being effective only when said secondary relay is deenergized, and means for rendering said motor active in response to alternating current applied to said input terminals only provided that said secondary relay is deenergized.

4. A timer having two input terminals to which alternating current is selectively applied for operation of the timer comprising, an alternating current constant speed motor, an elevationally disposed tooth rack having contact points secured thereto, a magnetic clutch coupling said motor with said rack only when said magnetic clutch is energized, a secondary relay, circuit means including said contact points and a rectifier for energizing said secondary relay from energy applied to said input terminals when said rack is elevated by said motor to a predetermined elevationally adjustable position, stick circuit means efiective when said secondary relay is picked up to maintain that relay picked up dependent upon the alternating current applied to said input terminals, and clutch energization means for energizing said clutch in response to the application of alternating current to said input terminals, said means being effective only when said secondary relay is deenergized.

5. A timer of the character described having two input terminals to which alternating current is selectively applied comprising, an alternating current constant speed motor, an elevationallydisposed tooth rack having contact points secured thereto, a magnetic clutch coupling said motor with said rack only when said magnetic clutch is energized, a secondary relay, a rectifier, circuit means including said contact points and said rectifier for energizing said secondary relay from energy applied to said input terminals, said circuit means being rendered effective only when said rack is elevated by said motor to a predetermined elevationally adjustable position, stick circuit means including said rectifier for maintaining said secondary relay energized dependent upon alternating current energy applied to said input terminals, clutch energization means for energizing said clutch through said rectifier from said input terminals, said clutch energization means being effective only so long as said secondary relay is deenergized.

JOSEPH F. MERKEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,421,157 Bouton June 2'7, 1922 2,237,390 Miskelly Apr. 8, 1941 2,261,396 McWhirter Nov. 4, 1941 2,269,973 Hathaway Jan. 13, 1942 2,272,568 Little Feb. 10, 1942 2,388,686 Habig Nov. 13, 1945 2,440,480 Lewis Apr. 2'7, 1948

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