US3207873A

US3207873A - Ratchet switch device employing spring means which applies tension and torsion to a pivoted armature

Info

Publication number: US3207873A
Application number: US205762A
Authority: US
Inventors: John L Slonneger
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1962-06-27
Filing date: 1962-06-27
Publication date: 1965-09-21
Anticipated expiration: 1982-09-21

Description

Sept- 21, 1965 J. sLoNNEGE-R 3,207,873

RATCHET SWITCH DEVICE EMPLOYING SPRING MEANS WHICH APPLIES TENSION AND TORSION TO A PIVOTED ARMATURE Filed June 27, 1962 3 Sheets-Sheet 1 Sept. 21, 1965 J, L. sLoNNl-:GER 3,207,873

RATCHET SWITCH DEVICE EMPLOYING SPRING MEANS WHICH APPLIES TENSION AND TORSION TO A PIVOTED ARMATURE Filed June 27, 1962 5 Sheets-Sheet 2 /4//3 Atto/ea Sept 2l, 1965 J. L sLoNNEGx-:R 3,207,873

RATCHET SWITCH DEVICE EMPLOYING SPRING MEANS WHICH APPLIES TENSION AND TORSION TO A PIVOTED ARMATURE Filed June 27. 1962 5 Sheets-Sheet 3 5 w/ TCH 65@ 65 si Sw/rf/f l @s 75 654 65 7 ac czasfp 5a' 75 F/@sr .S1600/v0 7717/90 Fay/PTH Pas//a/v Pas/r/a/v Pas/ r/o/v Pas/ rfa/v .57i/ew of United States Patent O 3,207,873 RATCHE'I SWITCH DEVICE EMPLOYING SPRING MEANS WHICH APPLIES TENSION AND TOR- SION T A PIVOTED ARMATURE John L. Slonneger, Morrison, Ill., assignor to General Electric Company, a corporation of New York Filed June 27, 1962, Ser. No. 205,762 Claims. (Cl. 200-105) My invention relates to electromagnetic relays and more particularly to electromagnetic stepping relays which control a plurality of switches in a predetermined sequence.

An important object of my invention is to provide an improved electromagnetic relay which is of novel structure and efficient in operation.

Another object of this invention is to provide an irnproved electromagnetic stepping relay which controls a plurality of separate switches in a predetermined sequence.

An additional object of this invention is to provide an improved switch operating mechanism for an electromagnetic stepping relay which controls a plurality of individual switches in a sequential manner.

A still further object of this invention is to provide an improved electromagnetic stepping relay which is compact, dependable in use and economical to manufacture.

In carrying out my invention, in one form thereof, I apply it to an electromagnetic relay having a frame, an electromagnetic coil mounted on the frame, and an armature pivotally mounted on the frame for attraction from a normal first position to a second position upon energizetion of the coil. For sequentially operating a plurality of switches, the relay includes a ratchet wheel which is mounted near one end of the pivoted armature. The ratchet wheel is connected to a plurality of rotary cams which operate the respective switches. For operating the ratchet wheel in response to the electromagnetic coil, a driving pawl is fastened to the one end of the armature which is adjacent the ratchet wheel to rotatably step the ratchet wheel through an angular interval each time the armature is attracted from its first position to a second position. With such an arrangement, in accordance with the present invention, there is provided a coil spring which is disposed in tension between the pawl carrying end of the armature and the frame. This spring biases the armature in a first direction to return it to its first position upon deenergization of the coil. The spring is also arranged in torsion to urge the driving pawl into mechanical engagement with the teeth of the ratchet wheel for operating the ratchet wheel. With such an approach, a single spring thus effectively controls the operation of the larmature by the coil and it `also helps to control the operation of the ratchet wheel by the relay armature.

Further aspects of my invention, will become apparent hereinafter, and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention. The invention, however, as to organization and method of operation, together with other objects and advantages thereof, may best be understood by reference to the following description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side elevation view of an electromagnetic stepping relay embodying my invention, with the armature Vshown in its attracted position;

FIG. la is a sectional view taken generally along a line 1ct-1a of FIG. l;`

FIG. 2 is a View similar to that of FIG. 1 but showing the armature in its unattracted or deenergized position;

FIG. 3 is a plan view of the relay looking down on the relay armature and three stepping cams;

FIG. 4 is a right end view of the relay, as shown in FIG. 1;

FIG. 5 is a left end view of the relay, as shown in FIG. l;

FIG. 6 is a bottom view of the relay, as shown in FIG. l;

FIG. 7 is a fragmentary sectional View taken generally along the line 7-7 of FIG. l;

FIG. 8 is a sectional view taken along the line 8 8 of FIG. 1 and showing the interior structure of one of the single-pole double-thr-ow switches;

FIG. 9 is a fragmentary perspective View showing the switch actuating cams, the ratchet wheel, the actuating end of the driving pawl, and the actuating arms of the three switches which are controlled by their respective cams; and

FIG. 10 is a schematic representation showing the cams and the switch actuating arms for the various switch positions provided by the relay of FIG. 1.

Referring first to FIGS. l-6, I have shown therein an electromagnetic stepping relay 1 which embodies my invention in one form thereof. The relay 1 comprises a frame 3, and on the right side thereof (viewing FIGS. 1 and 2), there is included a generally L-shaped yoke 5 formed of magnetic material. Mounted on the foot portion 7 of the yoke 5 is an electromagnet 9 comprising a coil 11 wound on an insulating spool 13 which is in turn positioned around an axial iron core 15. (See FIG. 2.)

Positioned on the yoke 5 for actuation by the electromagnet 9 is a laminated armature member 17. The armature 17 is positioned above the electromagnet 9, and near its left-hand side (as shown in FIGS. 1, 2 and 3 of the drawings) it extends through a recess 19 in the upper end of the yoke 5. The armature 17 includes grooves 21 in each side thereof which iit over the sides lof the recess 19 and thereby prevent lateral shifting of the armature. The grooves 21, however, are somewhat wider than the thickness of the yoke 5, so that the fitting of the grooves 21 over the yoke does not prevent movement between the armature and the yoke. As can be seen from a comparison of FIGS. 1 and 2, the armature 17 is pivotable with regard to the yoke 5, with the bottom surface 23 of the yoke recess 19 serving as the pivot point. To help control the operation of armature 17, it is normally spring biased away from the electromagnet 9 by means of a helical spring 25 connected in tension between the left hand side of the armature (viewing FIGS. 1 and 2 of the drawings) and a tab 27 formed on the yoke 5. The arrangement of spring 25 and its functioning in the relay 1, as will become apparent hereinafter, constitutes an important aspect of my invention.

As best shown in FIG. 2, the armature member 17 includes three laminations 17a which are of substantially uniform configuration and are stacked, generally, one upon the other. Between the bottom and middle laminations 17a (viewing FIG. 2) there is sandwiched a driving element 29. The element 29 is constructed from thin bronze or steel material and includes a iiat body section 31, a generally L-shaped driving pawl 33, and an L- Yshaped stop 35. The body section 31 is disposed between the middle lamination and the bottom lamination of the armature member 17, as shown in FIG. 2, and it is slotted in conformance with a group of aligned slots 37 formed in the laminations near the left side thereof (viewing FIG. 3). A hook 39 is formed on an edge 39a of the body section 31 for disposition within the aligned slots 37 of the laminations. Hook 39 serves to receive looped end 25a of control spring 25 (as shown in FIG. la), the other looped end 25b of the spring 25 being positioned within appropriate grooves formed on tab 27 of the yoke 5.

The pawl 33 extends upwardly from the outer edge of body section 31, as shown in FIGS. 1 and 2, and then perpendicularly outwardly to the left of the body section for extension through window 41 (FIG. 4) on the right side of the frame 3, As shall be further understood hereinafter, inner edge 43 of the `actuating section of the pawl (FIGS. 3 and 9) drives ratchet wheel 45 in response to successive actuations of the armature member 17 upon energizations of coil 11.

To limit the downward movement of the lift side of armature member 17 upon deenergization of coil 11, the stop 35 of the driving element 29 has its outer leg extended through window 47 (FIG. 7) for engagement with its bottom edge. To limit the upward movement of the left end of armature member 17 in response to energization of the coil 11, and primarily to overcome the residual magnetism force between the armature 17 and core 15, spring element 49 is riveted to this end of the armateure member 17 (see FIG. 3). Spring 49 includes an L-shaped section 51 (FIG. 1) having an arm which extends through the window 41. As shown best in FIG. 7, upon energization of the coil, the arm of the spring member 49 in window 41 engages the upper edge of window 41 to deflect spring 49 when armature 17 closes on core 15 and provides the force required to overcome the residual magnetism left in the armature 17 and core 15 at the instant the coil 11 is deenergized.

Discussing further the structure of relay 1, as shown in FIG. 2 on the left side of frame 3 there is provided a U-shaped frame section 53. The frame section 53 comprises a pair of upright

opposed plates

55a and 55b, and a bight section 57 connected thereto. Between plates 55a and 55h, the aforementioned ratchet wheel 45 and three switch actuating

cams

61, and 63 and 65 are coaxially arranged for rotation about an axis in perpendicular relationship to the

plates

55a and 55b by means of a suitable shaft 67 rotatably suported in bear- .ing apertures of the

plates

55a and 55b. The shaft 67 has shouldered outer ends which engage the opposed inner surfaces of the

plates

55a and 55b adjacent the bearing apertures to limit axial movement of the shaft in the frame. As shown in FIGS. 1-3, the

cams

61, 63, and 65 are positioned for rotation respectively over

switch actuating arms

71, 73 and 75, to sequentially operate a row of box shaped

respective switches

81, 83 yand 85 in response to the intermittent stepping of ratchet wheel 45 by pawl 33.

Turing now to an important aspect of the present invention which concerns a simplified means for helping t control the operation of the armature member 17 by the coil 11 and also helping to control the operation of the ratchet wheel 45 by the armature member 17, attention is directed to FIGS. 1, 1a and 2. To resiliently bias the armature member 17 to its normal position away from the electromagnet 9, the previously mentioned helical spring 25 is stretched in tension between tab 27 of the yoke 5 and hook 39 of the armature member assembly. It will thus be seen that the spring 25 pulls downwardly on the left-hand end of the armature member 17 (FIGS. 1 and 2) to continuously bias the right-hand portion of the armature member upwardly and away from the electromagnet 9 (i.e., in a counterclockwise direction of rotation .about its pivots).

In accordance with the teaching of the present invention, in .addition to being in tension between its looped ends 25a and 25b, the spring 25 is also twisted so that it is arranged in torsion between its ends to bias the pawl 33 into normal meshing relationship with the teeth of ratchet wheel 45. More specifically, as shown in FIG. 5

la, one of the looped ends 25a or 25h of spring 25, such as for example end 25h, may be first positioned in relatively fixed engagement with tab 27 of the frame 3. In asembling the spring 25 in the relay, the other looped end thereof, such as for example looped end 25a is then twisted with respect to the previously secured end of the spring, as indicated by the curved arrows in FIGS. 3

and 6, and thereafter secured to the frame or to the armature member, such as for example to hook 39 of the armature member 17. In the particular illustrated relay, the spring 25 has been twisted angularly through approximately one turn. The torsional force which is imparted to the spring 25 between its ends provides a biasing force for normally urging the inner driving edge 43 of the pawl 33 in a downward direction (viewing FIG. 3), toward the teeth of the ratchet wheel, whereby the pawl 33 is urged into meshing engagement with the teeth of the ratchet wheel 45. (See FIG. 7.)

It lwill thus be seen that the control spring 25 performs two separate and distinct functions in the relay 1 in a simple and expeditious manner. Spring 25 acts upon the armature member 17 to bias it in a downward first direction (viewing FIG. 2) for returning the armature to its unattracted position upon deenergization of the coil 11. In addition, the control spring 25 is arranged in torsion to act upon the armature member 17 for urging the pawl 33 in a downward second direction (viewing FIG. 3) transverse to the rst direction for mechanical driving engagement with the ratchet wheel 45. The control spring 25 thus effectively and economically helps to control the operation of the armature member 17 by the coil 11 and also helps to control the operation of the ratchet wheel 45 by the armature member 17.

Turning now to a description of the cam actuating arrangement for the electromagnetic relay 1, attention is initially directed to FIGS. 7, 8, 9 and 10. In the illustrated relay 1, the

cams

61 and 63 are integrally molded together as a one piece construction and cam 65 is integrally molded together with ratchet wheel 45 as a oneV piece construction. The

cams

61, 63, 65 and the ratchet wheel 45 are suitably secured to shaft 67 for rotation therewith in aligned bearing apertures of the

plates

55a and 55b Ratchet wheel 45 comprises a series of 12 teeth on its periphery, which teeth are spaced angularly apart by y30 degrees. Each time the electromagnet 9 is energized, the armature 17 is attracted toward .coil 1.1 and the pawl 33 engages underneath a tooth of ratchet wheel 45 (viewing FIG. 7) to drive the stacked yassemblage of the cams and ratchet wheel in a counterclockwise direction of rotation (viewing FIG. 9) for an angular interval of approximately 30 degrees.

The mode of operation of the

switches

81, 83 and 85 by their

respective cams

61, 63 and 65 is shown schematically in FIG. 10. Considering rst the configuration of cam 61, it will be seen that this cam is of the radial type and includes on its periphery six outermost cylindrical surfaces 61a having the same radius of curvature and uniform length, as well as six specially congured notches 61b of identical shape. Viewing further the cam 61 in FIG. 10, it will be noted that the centers of the outer cylindrical `surfaces 61a are spaced apart by approximately 60 degrees. Each pair of adjacent cylindrical surfaces 61a has one of the notches 61b formed therebetween. The notches 61b are uniformly positioned on the periphery of the cam 61 and each of these notches includes an abrupt forward slope 61C (which is generally radial to the cam and `stems from one cylindrical surface 61a), a curved inner end 61d which is connected to the inner end of the abrupt slope 61C, and a gradual slope 61e (which connects the other side of the curved inner end 61d to another cylindrical outer surface 61a).

Each time the electromagnet 9 is energized the ratchet wheel 45 rotates 30 degrees and thereupon also rotates the three

coaxial cams

61, 63 and 65 for 30 degrees in a counterclockwise direction, viewing FIG. 10. As illustrated schematically in FIG. l0, the cam 61 is thus stepped fior 30 degrees in a counterclockwise direction to operate the switch actuating arm 71 of switch 81. The arm 71 of switch 81 has a looped actuating finger 71a which is disposed toward the axis of the cam 61. For the iirst position of the schematic representation in FIG. 10, the actuating ringer 71a of actuator 71 is shown positioned within one of the notches 6111 of cam 61. When the cam 61 and switch 81 are in this position, a looped over free end 71b of finger 71a is in engagement with the abrupt slope 61C of the cam notch 61b and the curved part of the looped end of the actuator engages the curved inner surface 61d of the cam. When switch actuator 71 is in its rst position (viewing FIG. 10), switch 81 has its actuating plunger in an upper or outer position, and this plunger is spring biased into engagement with the elongated body section of the actuator to urge the actuating finger 71a outwardly away from the switch.

The interior structure of switch 81 is not shown for purposes of simplification, but this switch is a conventional type of single-pole single-throw switch, similar to switch 83 of FIG. 8. More particularly, the switch 81 is similar to switch 83 shown in FIG. 8 in that it includes a snap acting flipper mechanism which supports a movable contact 89 that is in normal disengagement with upper fixed contact 93 when the plunger is in its outermost position and snaps the movable contact 89 into engagement with contact 93 when the plunger is depressed. The switch 81 differs from switch 83 in that it does not include a second xed contact 91 or its associated terminal c.

Viewing further the schematic arrangement of FIG. 10, it will be noted that when the looped finger 71a of actuator 71 of the switch 81 is located in the notch 61b for the first position of the relay, this looped end also serves as a detent for the cams and the ratchet wheel, thereby precluding the possibility of any undesirable rotative movement of the

cams

61, 63, 65 and the ratchet wheel 45 about their axis.

As further shown in the schematic representation of FIG. 10, for the second position of the relay, the ratchet wheel has been rotated 30 degrees, and as a consequence thereof cam 61 has likewise been rotated 30 degrees in a counterclockwise direction from its rst position. During the movement of cam 61 from its first position to its second position, the looped end 71a of actuator 71 thereupon pivots in a clockwise direction of rotation (viewing FIG. about the axis of the actuator 71 in response to a camming effect exerted thereupon by the gradual sloped surface 61e of the associated notch 61b. Thus, when cam 61 rotates from its first position to its second position, the curved part of the looped end 71b of actuator 71 is cammed outwardly from notch 61b by notch surface 61e so that it then rides along the cylindrical outer surface 61a of cam 61. As the actuator 71 pivots, the flat section of the actuator 71 forces the plunger of switch 81 downwardly into engagement with the actuating mechvanism of the switch to close the

contacts

89 and 93 thereof.

When cam 61 is operated by the ratchet wheel 45 from its second position to its third position, viewing FIG. 10, the looped end 71a of the actuator 71 drops olf the abrupt shoulder of the next notch 61b and engages the abrupt slope 61C thereof. The plunger of switch 81 is thereupon allowed to return to its normal outermost position and the

contacts

89 and 93 of the switch 81 are opened. The actuator 71 again serves as a detent by prohibiting undesirable rotative movement of the cam and ratchet assembly for the third relay position.

When the cam 61 is rotated from its third position to its fourth position (viewing FIG. l0), the actuator 71 is moved in the same manner previously described for movement of the cam from its first position to its second position, the plunger of the switch 81 being thereupon closed for the fourth position to close the switch contacts.

Turning now to a discussion of the mode of operation of switch 83, it should initially be noted that switch 83 is a single-pole double-throw switch. As shown in FIG. 8, switch 83 includes a snap acting flipper mechanism which supports a movable contact 89 that is in normal engagement with the bottom fixed contact 91 when the plunger of the switch is in its outermost position. When the plunger of switch 83 is depressed, the ipper mechanism snaps the movable contact 89 supported thereby into engagement with the upper fixed contact 93. Terminal a furnishes an external connection means for movable contact 89, and terminals b and c provide external connection means for the respective fixed

contacts

93 and 91.

The configuration of the cam 63, which actuates the switch 83, is somewhat similar to the configuration of the previously described cam 61. More particularly, vcam 63 is generally of the same axial length as cam 61 (as shown in FIG. 2) and it includes on its periphery three angularly spaced outer cylindrical surfaces 63a (as shown in FIG. 10) having the `sarne radius of curvature. Also on its periphery, between each pair of adjacent outer cylindrical surfaces 63a, cam 63 includes a notch 63b which is identical in configuration to the notches 61b of cam 61. The centers of the outer cylindrical surfaces 63a of the cam 63 are spaced apart by 120 degrees, as also are the notches 63h.

When the relay 1 is in its first position, as shown schematically in FIG. 10, the looped actuating finger 73a of actuating arm 73, which is identical in structure to the actuating arm 71 of switch 81, is disposed on the cylindrical periphery 63a of the cam 63 near one of the notches 63h. With the switch actuator 73 in this condition, the plunger of switch 83 is depressed by actuator 73 and the

contacts

89 and 93 of the switch are closed to energize a circuit connected across terminals a, b (see also FIG. 8).

When the ratchet wheel 45 rotates cam 63 from its first position to its second position, the looped actuating linger 73a of the actuator 73 drops olf the shoulder of the cam and enters the previously adjacent notch 63b (as shown in FIG. l0). Outer end section 7317 of the finger 73a thereupon engages abrupt slope 63e of the cam notch 63h and the curved part of the looped end of the actuator engages inner curved surface 63d of the notch 6311. During movement of cam 63 toits second position, switch arm 73 is pivoted in a counterclockwise direction by the actuating plunger of switch 83 and thereby allows the

contacts

89 and 91 to snap to their normally closed position (as shown in FIG. 8), the

contacts

89, 93 being returned to their normally open position.

When the

cams

61, 63 and 65 are in their second position (viewing FIG. l0), the engagement bof the looped actuating nger 73a of actuator 73 with notch 63b precludes any undesirable rotational movement of the cam stack and ratchet wheel, thereby providing a detent effect for the rotatable operating mechanism. This detenting operation is the same as that previously described for the actuator 71 and cam 61 when the relay is in the irst and the third positions.

When the cam 63 rotates in its counterclockwise driven direction from its second position to its third position, as :shown in FIG. l0, the looped finger 73a of the actuator 73 is cammed outwardly and away from the axis of rotation of the cam 63 by riding along the gradual slope 63e yof notch 63b until it reaches the outer cylindrical periphery 63a of the cam 63. The pivoting movement of 'actuator 73 then engages the plunger of switch 83 to depress

contacts

89 and 93 back to their closed position.

When cam `63 is rotated from its third posiiton to its fourth position .the looped finger of the actuator 73 continues to ride along the outer cylindrical surface 63a of the cam and the

contacts

89, 93 of switch 83 remain in their closed position.`

ITurning now to an explanation of the mode of operation of the switch 85, this switch is identical in structure to the switch 83, which is shown in FIG. 8; More particularly, the switch 85 is a single-pole double-throw switch and it is operated by a cam 65 which is identical in configuration to the previously described cam 63. Thus, as shown in FIG. d0, cam 65 has the same axial length as cam 61 and on its periphery it includes three outer cylindrical surfaces 65a having their centers spaced apart by 120 degrees. Between each pair of adjacent outer cylindrical surfaces 65a there is disposed a notch 65b. Each of the notches 6511 includes an abrupt slope 65C, yan inner curved surface 65d and a gradual slope 65e, the respective notches being of the same construction as land arranged uniformally in the same manner as the notches 63h of cam 63.

For the first position of the electromagnetic relay 1, as shown in FIG. l0, the cam 65 is angularly located relative to the ca'ms 6'1 and 63 so that the looped actuating finger 75a of the switch actuator 75, which is identical structurally to actuators 71 and 73, rides along one of the cams cylindrical outer surfaces 65a. With switch actuator 75 in this position the flat main portion thereof compresses the plunger of the switch 85 and thereby causes the contacts 89 'and '93 (FIG. 8) to engage. This contact connection .closes a circuit across the terminals a and b. When the ratchet wheel 45 of the electromagnetic relay 1 is then stepped 30 degrees to its second position, as shown in FIG. 10, the cam 65 maintains switch actuator 75 in the same position and the cont-

acts

89, 93 remain closed.

When the electromagnetic relay 1 steps the ratchet wheel 45 from the second position to the third position, the cam 65 continues to maintain the switch actuator 75 in its downward or depressed position and the switch plunger `85 remains in compression to keep the circuit closed across terminals a and b.

When the electromagnetic relay 1 steps the ratchet wheel 45 from its third to its fourth position, as shown in FIG. l0, the ca'm 65 rotates through an angle of 30 degrees, the angular equivalent to one tooth of the ratchet wheel. The actuating loop 75a of the actuator 75 of the switch is then received within notch 65b of the cam `65. Actuator 75 thereupon pivots in a counterclockwise direction in response to the plunger of switch 85. This allows the actuating plunger of switch 85 to move from its depressed to its outermost position and the contacts 89 and 911 are thereupon snapped to closure to energize the circuit connected across terminals a and c of the switch and deenergize the circuit connected across terminals a and b.

When cam 65 is in the fourth position from the electromagnetic relay as shown in FIG. 10, the surface 75b and the curved section of the loop 75a of the actuating arm 75 engage notch 65b to preclude any undesirable rotation of the cams and ratchet wheel for that position.

With the above described arrangement of

cams

61, 63 and l65, each time the ratchet wheel 45 is stepped 30 degrees by energiza'tion of armature member 17, one of the three

switch arms

71,73 or 75 is compressed against its switch plunger, another of the

switch arms

71, 73 or 75 is released from its switch plunger, 'and the

third switch arm

71, 73 or 75 remains in the same position. Thus, for example (viewing FIG. l), when the relay steps the ratchet wheel 45 from the first position to the second position the switch arm 71 compresses its switch plunger, switch arm 73 releases its switch plunger, and switch arm 75 remains in the same position with respect to its plunger. Then, as a further example, when the ratchet wheel 45 is driven further from the second position to the third position, the switch arm 71 releases its switch plunger, switch arm 73 compresses its switch plunger, and switch arm 75 again remains in the same position. When the ratchet wheel steps the cam stack from its third to its fourth position the actuator 71 is compressed, actuator 73 remains in the same position, and actuator 75 is released, etc. With such an arrangement of the cams and switches, even though two switches are actuated each time the ratchet wheel is stepped 30 degrees a working force equivalent to that required for actuating only one switch is required because only one switch actuator is being cammed into compressive engagement with its switch actuator. In view of this minimal force requirement to actuate a plurality of separate switches, the amount of 0f driving power required for stepping the ratchet wheel is minimized, thereby enhancing the economy of manufacture for the relay.

It will now therefore be seen that I have provided a simplified and efficient structure for an electromagnetic relay which is capable of operating a plurality of switches.` It will further be understood that this improved relay is economical to manufacture and constructed in such a manner that it lends itself to a wide variety of applications.

While in accordance with the patent statutes, I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from my invention, and I therefore aim in the following claims to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electromagnetic relay comprising a frame, switch means supported by said frame, an electromagnetic coil mounted on said frame, an armature pivotally mounted on said frame for attraction from a first position to a second position upon energization of said coil, rotatable means for operating said switch means, driving means including said armature for operating said rotatable means, and a control spring acting upon said armature in a first direction for returning said armature to its first position upon deenergization of said coil, said control spring being arranged to act upon said armature in a second direction for urging said driving means into mechanical engagement with said rotatable means, whereby said spring controls the operation of said armature by said coil and also imparts a controlling effect upon the operation of said rotatable means by said armature.

2. An electromagnetic relay comprising a frame, switch means supported by said frame, an electromagnetic coil mounted on said frame, an armature pivotally mounted on said frame for attraction from a first position to a second position upon energization of said coil, a rotatable member for operating said switch means, driving means including said armature for operating said rotatable member, and a control spring disposed in tension between said frame and said armature and acting upon said armature in a first direction for returning said armature to its first position upon deenergization of said coil, said control spring being arranged in torsion to act upon said armature in a second direction for urging said driving means into mechanical engagement with rotatable member, whereby said spring controls the operation of said armature by said coil and also imparts a controlling effect upon the operation of said rotatable member by said armature.

3. An electromagnetic relay comprising a frame, switch means supported by said frame, an electromagnetic coil mounted on said frame, an armature pivotally mounted on said frame for attraction from a first position to a second position upon energization of said coil, a rotatable means including a ratchet wheel for operating said switch means, driving means including said armature for operating said ratchet wheel, and a control spring disposed in tension between said frame and said armature and acting upon said armature in a first direction for returning said armature to its first position upon deenergization of said coil, said control spring being arranged in torsion between said driving means and said frame to act upon said armature in a second direction transverse to said first direction for urging said driving means into mechanical engagement with said ratchet wheel, whereby said spring controls the operation of said armature by said coil and also imparts a controlling effect upon the operation of said rotatable member by said armature.

4. An electromagnetic relay comprising a frame, an

electromagnetic coil mounted on said frame, an armature pivotally mounted on said frame for attraction from a first position to a second position upon energization of said coil a rotatable operating unit including a ratchet wheel and a plurality of cams, a pawl disposed on said armatureA and engageable with said ratchet wheel thereby to drive said operating unit in step by step fashion upon attraction of said armature by said coil, a plurality of switch units each of which is operated by one of said cams, and a control spring disposed in tension between said frame and said pawl alnd acting upon said armature in a rst direction for returning said armature to its first position upon deenergization of said coil, said control spring being arranged in torsion between said pawl and said frame to act upon said pawl in a second direction generally perpendicular to said rst direction for urging said pawl into mechanical engagement with said rotatable member, whereby said spring controls the operation of said armature by said coil and also imparts a controlling etfect upon the operation of said ratchet wheel by said pawl.

5. An electromagnetic relay comprising a frame, an electromagnetic coil mounted on said frame, an armature pivotally mounted on said frame for attraction from a rst position to a second position upon energization of said coil, a rotatable operating unit including a ratchet wheel and a plurality of cams, a pawl disposed on said armature and engageable with said ratchet wheel thereby to drive said operating unit in step by step fashion upon successive attractions of said armature by said coil, a plurality of switch units each of which is respectively operated by an associated one of said cams, each of said switch units including an actuating lever arm acted upon by an associated cam thereby to operate said switch unit, said cams and actuating arms being arranged in said device so that for each cam position one of said plurality of cams cooperates with its associated switch actuating arm thereby to preclude any undesirable rotative movement of the rotatable operating unit, and a control spring disposed in tension between said frame and said pawl and acting upon said armature in a first direction for returning said armature to its iirst position upon deenergization of said coil, said control spring being arranged in torsion between said pawl and said frame to act upon said pawl in a second direction generally perpendicular to said first direction for urging said pawl into mechanical engagement with said rotatable member, whereby said spring controls the operation of said armature by said coil and also imparts a controlling effect upon the operation of said ratchet wheel by said pawl.

6. The electromagnetic relay of claim 1 wherein said switch means comprises a plurality of aligned cams driven sequentially through a series of cam positions in a step by step fashion by said rotatable means, and a plurality of switch units operated respectively by said cams, each switch unit including an actuator means acted upon by an associated cam thereby to operate said switch unit, said cams and actuator means being arranged so that for each cam position one of said plurality of cams cooperates with its associated actuator means thereby to preclude any undesirable rotative movement of all of said cams.

7. The electromagnetic relay of claim 1 wherein said switch means comprises a plurality of coaxially stacked cams driven sequentially through a series of cam positions in step by step fashion by said rotatable means, each of said cams including an external cylindrical surface with a series of angularly spaced actuating notches formed therein, and a plurality of switch units operated repec tively by said cams, each switch unit including an actuating lever having a looped finger formed at its free end, said looped finger being arranged to ride upon the external surface of an associated cam for operation of an associated switch thereby, said plurality of cams and their associated actuating levers being arranged in said device so that 'for each cam position one of the`notches of a certain predetermined cam receives the looped finger of its associated switch actuating lever, said linger of said lever cooperating with said one notch of said cam thereby to preclude any undesirable rotative movement of said switch means. v

8. In an electromagnetic-relay wherein a pivoted armature is attracted fron one -position to another by an electromagnet upon energization of a coil, a rotatable operating unit including a plurality of coaxially arranged cams intermittently driven in step by step fashion by said armature, a control spring arranged to act upon said armature in one direction to return said armature to said one position upon deenergization of the coil, said spring also being arranged to act upon said armature in another direction thereby to help effect the operation of said rotatable unit by said armature, and a plurality of switch units each of which is operated by one of said cams, at least two of said switch units being concurrently operated by their respective cams at certain positions of said rotatable operating unit, said switch units each comprising an actuator spring biased to a normal position and operated to a second position in response to a force exerted thereupon by one of said cams, said cams and switch units being arranged so that whenever said two switch units are concurrently operated by their respective cams a force is exerted upon the actuator of only one of said two switch units and the actuator of said other switch unit is released, thereby minimizing the force required to drive said rotatable operating unit by said armature.

9. The electromagnetic relay of claim 8 wherein the control spring is a coil spring that exerts a biasing force along its axis to urge the armature in the one direction upon deenergization ofthe coil, said spring being arranged in torsion to urge the armature in the other direction for driving the operating unit.

10. An electromagnetic relay comprising a frame, an electromagnetic coil mounted on said frame, an armature pivotally mounted'on said frame for attraction from a lirst position to a second position upon energization of said coil, a rotatable operating unit including a ratchet wheel and a plurality of cams, a pawl disposed on said armature and engageable with said ratchet wheel thereby to drive said operating unit in step by step fashion upon attractions of said armature by said coil, a plurality of switch units each of which is respectively operated by an associated one of said cams, each of said switch units including an actuating lever arm acted upon by an associated cam thereby to operate said switch unit, said cams and actuating arms being arranged in said device so that for each cam position one of said plurality of cams cooperates with its associated switch actuating arm thereby to preclude any undesirable rotative movement of the rotatable operating unit, at least two of said switch units being concurrently operated by their respective cams at certain positions of said rotatable operating unit, the actuating levers of said cams being spring biased to a normal position and movable to a second position in response to a force exerted thereupon by one of said cams, said cams and switch units being arranged so that whenever two switch units are concurrently operated by their respective cams a force is exerted upon the actuator `of only one of the two switch units by its associated cam, the actuator of the other switch unit being released by its associated cam, thereby minimizing the force required to drive said rotatable unit by said armature, and a control spring disposed in tension between said frame and said pawl and acting upon said armature in a iirst direction for returning said armature to its first position upon deenergization ot' said coil, said control spring being arranged in torsion between said pawl and said frame to act upon said pawl in a second direction generally perpendicular to said first direction for urging said pawl into mechanical engagement with said rotatable member, whereby said spring controls the operation of said armature by said coil and also imparrts a controlling effect upon the operation of said rathet Wheel by said pawl.

References Cited by the Examiner UNITED STATES PATENT Sv l2 Y l Stephenson v 267-1 Burnside 200-105 Mason 200-105 Olsson `20G-405 BERNARD A, GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.