US3435389A

US3435389A - Electromagnetic contactor having cam means for operating auxiliary switch

Info

Publication number: US3435389A
Application number: US631935A
Authority: US
Inventors: Charles R Mikolic; Lawrence A Burton
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1967-04-19
Filing date: 1967-04-19
Publication date: 1969-03-25
Anticipated expiration: 1986-03-25
Also published as: GB1174756A

Description

March 25, 1969 Q R MlKOLlC ET Al. 3,435,389

ELECTROMAGNETIC CONTACTOR HAVING CAM MEANS FOR OPERATING AUXILIARY SWITCH Filed April 19, 1967 Sheet March 25, 1969 c. R. MIKOLIC ET AL 3,435,389

ELECTROMAGNETIC CONTACTOR HAVING CAM MEANS FOR OPERATING AUXILIARY SWITCH nled Aprll 19 1967 sheet 5 of 2 987311K' 62a 62a X United States Patent Oiiice 3,435,389 Patented Mar. 25, 1969 U.S. Cl. 335-121 34 Claims ABSTRACT F THE DISCLOSURE An electromagneitc contactor having a contact carrier provided with an inclined plane camming slot and an auxiliary switch having floating contacts operated by a cam follower movable perpendicular to the operating direction of the contact carrier to eliminate the reaction force of the auxiliary switch on .the electromagnet in the operated position.

This invention relates to electromagnetic contactors and in particular to such contact-ors having a set of main contacts for opening and closing a power circuit and additional auxiliary contacts for making and interrupting control circuits of the contactor.

Electromagnetic contactors have main contacts which carry the load current of the motor or other device being controlled and are often provided with one or more auxiliary, or control, switches. The auxiliary switches are interposed in the control circuit of the contactor, or in the control circuit of a related controller, and generally serve an interlocking function to insure a desired sequence of contactor operation. The auxiliary switches for dilerent contactors have varying arrangements of normally open and normally closed contacts and return springs to hold the normally closed contacts in engagement when the contactor is not energized. The electromagnet of the contactor must be capable of exerting' suilicient force to operate the main contacts and to increase the loading of the auxiliary switch return springs and to operate the auxiliary switch contacts and hold them engaged under relatively high pressure contact. The force required to hold the auxiliary contacts engaged varied with the contact arrangement of the auxiliary switch. Consequently the electromagnet of prior art contactors had to be sufficiently large to h-old the main and auxiliary switch contacts operated for the embodiment having the largest number of sets of auxiliary contacts, thereby requiring the electromagnet to be unnecessarily large for other embodiments and resulting in a different operating characteristic when the auxiliary contact arv rangement was changed.

It is an object of the invention to provide an electromagnetic contactor having an auxiliary switch wherein the electromagnet is not required to exert a force to maintain the auxiliary contacts operated, thereby permitting the electromagnet to 'be of smaller size than in prior art devices.

It is a further object of the invention to provide such an electromagnetic contactor wherein the force which the electromagnet must exert to operate the auxiliary switch is considerably smaller than in prior art devices.

Another object is to provide such an electromagnetic contactor whose operating characteristics remain essentially constant regardless of the contact arrangement of the auxiliary switch or the number of auxiliary switches operated by it.

A still further object is to provide an electromagnetic contactor auxiliary switch which provides a different contact arrangement by mere reversal of the mounting position of the auxiliary switch on the contactor housing and without rearrangement of the auxiliary switch contacts or other components.

These and other objects and advantages of theinvention will be more readily apparent from the following detailed description when considered in conjunction with the accompanying drawing wherein:

FIG. l is an exploded side view, partly in section, of the electromagnetic contactor of the invention having an auxiliary switch;

FIGS. 2 and 3 are views taken along lines II-II and III-III respectively of FIG. l;

FIGS. 4 and 5 are lpartial views showing the normal and operated positions respectively of the cam means on the main contact carried relative to the ca-m follower operating pin of the auxiliary switch;

FIG. 6 is a front view of the cam means of an alternative embodiment of the contact adapted to actuate a plurality of auxiliary switches on each of the opposed sides of the contact housing;

FIG. 7 is a perspective view of the auxiliary switch of the invention;

FIG. 8 is a side view of the auxiliary switch of FIIG. 7;

FIG. 9 is a view taken along line IX-IX of FIG. 8;

FIGS. l0 and 11 are views taken along lines X-X and XI-XI respectively of FIG. 9;

FIGS. 12a and 12by show the normal and operated positions respectively of an auxiliary switch embodiment having two sets of normally open contacts, vthe positions of the actuating cam slot being shown in dotted lines;

FIGS. 13a and 13b show the normal and operated lpositions respectively of the auxiliary switch of FIG. 12 after its mouting position has been reversed on the contactor housing to thereby reverse the contact arrangement and provide two sets of normally closed contacts;

FIG. 14 illustrates an alternative embodiment of aux iliary switch having two sets of normally open and one set of normally closed contacts;

FIG. l5 is a perspective view of one of the auxiliary switch stationary contacts;

FIG. 16 is a perspective view of the contact carrier of the auxiliary switch; and

FIG. 17 is a cross sectional view through the auxiliary switch.

Referring to FIG. 1 of the drawing, the electromagnetic contactor of the invention includes an insulating housing 10, a movable contact assembly 11 reciprocable within housing 10, and an insulating cover 12 for the housing 10 substantially as disclosed in U.S. Patent 3,259,702 to Lawrence A. Burton and Gustav W. Doos, having the same assignee as this invention and to which reference is made for details of construction. Housing 10 is generally of box shape and is preferably molded of suitable insulating material such as gla-ss polyester to have a bottom wall 14 and pairs of opposed sidewalls 16 and 17. Internally threaded metallic inserts (not shown) may be molded within housing -bottom wall 14 to permit mounting of the contactor on Ia vertica-l wall of a switch enclosure. Housing 10 is open at the top to receive movable contact assembly 11 and a coil 18 which is preferably encapsulated in a thermosetting resin. Movable contact assembly 1-1 includes a main contact carrier 20 generally of inverted U-shape having spaced apart legs 21 (only one of which is shown in FIG. 1) aixed by an elongated bar 24 to an E-shaped lamina-ted, movable magnetic armature 22 disposed between the legs 21. Elongated bar 24 protrudes through apertures in legs 21 and armateur 22. Main contact carrier 20 supports a plurality of movable flat elongated metallic bridging contacts 25 (only one of which is seen in FIG.V1) carrying raised button contacts 26 at both ends thereof.

Housing has guideways 28 (see FIG. 2) in sidewalls 17 which slidably receive legs 21 of main contact carrier 20 and guide movable contact assembly 1-1 as it reciprocates within housing 10 toward and away from cover 12. Coil 18 may rest upon the upper ends (not shown) of the portions of housing 10 which define the guideways 28.

Removable cover 12 is preferably molded of the same insulating material as housing 10 and fits over and closes the open top of housing 10. Cover 12 has a generally flat portion 29 upon which two spaced apart rows of elongated flat metallic stationary contacts 30 are secured by screws 32 so that each stationary contact 30 in one set is in alignment with a stationary contact 30 in the other set. The inner end of each stationary contact 30 has a contact button 34 which is adapted to engage the contact button 26 at one end of movable bridging con tact 25 when main contact carrier 20 is actuated toward cover 12 by energization of coil 18, thereby bridging movable contact 25 rbetween aligned stationary contacts 30 on cover 12. Inwardly extending barriers 37 molded on cover 12 extend between the pairs of aligned sta tionary contacts 30 and protrude into grooves (not shown) in housing 10 when cover and housing are mated.

Terminals 39 for the stationary main contacts 30 are provided on housing 10, and electrical connections between terminals 39 on housing 10 and stationary contacts 30 on cover 12 are completed through plug-in type connectors formed by a pair of upstanding, spaced apart ears 40 on each terminal (only one of which can be seen in FIG. l) defining the female part of the plug-in connector and the fiat end 42 of each stationary contact 30 opposite contact button 34 which is the male part of the plug-in connector and is adapted to protrude with a squeeze fit between the spaced ears 40 when cover 12 and housing 10 are mated. Each terminal 39 is provided with a screw 44 for clamping a conductor. With such construction both the movable main contacts 25 and the stationary main contacts 30 are readily accessible for inspection and replacement when cover 12 is removed from housing 10. Along opposed sidewalls 17 housing 10 is provided with cutout portions 45 that mate with generally U-shapedprojections 46 on cover 12.

A stationary, E-shaped laminated magnetic core member 47 rests upon coil 18 so that the middle core leg (not shown) extends through a central window (not shown) in coil 18. When cover 12 is assembled onto housing 11 and secured thereto -by screws 48, resilient members 49 on barriers 37 push against stationary core member 47 so that it presses coil 18 against support portions of housing 10 and prevents movement of coil 18 and core members 47 relative to housing 10. Springs 50 on cover 12 engage laterally extending arms 53 on main contact car- -rier 20 when cover 12 is assembled to housing 10 and normally hold movable contact assembly 11 in its lowest position wherein movable main contacts 25 Iare disengaged from stationary contacts 30. Coil 18, stationary magnetic core member 47, and movable armature 22 form the elect-romagnet of the contactor.

In the preferred embodiment of the invention, each leg 21 of contact carrier 20 has a protuberance defining an inclined plane cam slot 55 therein, and sidewalls 17 of housing 10 have square auxiliary switch mounting openings 56 therein opposite cam slots 55 into which an auxiliary switch 58 may be assembled in either of two alternate positions so that a cam follower pin 59 for operating the auxiliary switch contacts fits into cam slot 55. Auxiliary switch 58 has different arrangements of normally open and normally closed contacts in the alternate positions. Housing 10 has wa-ll portions 60 perpendicular to sidewalls 17 which partially define auxiliary switch mounting opening 56 and which have hook-shaped protrusions `61 (see FIG. 3) into which projecting ears 62b on auxiliary switch 58 fit. Mounting screws 64 extending through clearance holes in a projecting shelf portion 65 on housing sidewall 17 which partially defines opening 56 may be threaded within metallic inserts molded within casing 70 of auxiliary switch 58 to support auxiliary switch 58 on contacter housing 10.

The movable contacts 85 (see FIGS. ll-14) of auxiliary switch 58 are supported by an auxiliary contact carrier 88 which floats within the auxiliary casing 70 and is integral with cam follower pin 59, and cam follower pin 59 normally occupies a position in the bottom of cam Slot 55, shown in FIG. 4, wherein the camming surfaces 71 are parallel to the direction of movement of main contact carrier 20 and the auxiliary switch contacts are thus normally held in position by the main contact carrier 20. Energization of coil 18 attracts movable magnetic armature 22, and main contact carrier 20 axed thereto, toward stationary core member 47, whereby the inclined plane cam slot 55 actuates cam follower pin 59 from the position shown in FIG. 4 to that shown in FIG. 5 as the legs 21 of contact carrier 20 slide in guideways 28 in contacter housing 10. It will be noted that the cam means defined by cam slot 55 and cam pin 59 is of the positive motion type and that the cam follower pin 59 is actuated by cam slot 55 in a direction perpendicular to the direction of movement of legs 21 of contact carrier 20. The mechanical advantage provided by the inclined plane camming slot 55 minimizes the force which the electromagnets must provide to operate the auxiliary switch contacts. It will also be noted that cam follower pin 59 is positively constrained in both the normal and operated positions of the main contact carrier 20 shown in FIGS. 4 and 5 respectively, and camming surfaces 72 parallel to the direction of reciprocation of main contact carrier 20 and adjacent the open end of cam slot 55 enable the main contact carrier 20 to hold the auxiliary switch contacts in operated position without any reaction force exerted in the direction that the main contact carrier 20 is reciprocated, thereby eliminating the necessity for the electromagnet to hold the auxiliary switch contacts operated and permitting substantial reduction in the size of the electromagnet.

This feature will be better appreciated with an understanding of the floating contact construction of the auxiliary switch 58 which will now be described. Auxiliary switch casing 70 is preferably a right angle prism, i.e., generally of box-shape, and preferably is molded of a suitable transparent insulating material such as polycarbonate to permit visual determination of the auxiliary switch contact arrangement. A cover 73 of similar material closes the open end of casing 70. Auxiliary switch casing 70 has two pairs of mounting ears 62a and 62h (see FIG. 7) described hereinbefore extending from opposite sidewalls thereof. Six elongated holes 75 in the bottom wall 74 of casing 70 communicate with the interior of casing 70 and are counterbored (see FIG. 17) to receive metallic stationary contacts 76 so that one flat portion 77 of each stationary contact 76 protrudes from casing 70 and forms a wiring terminal and the other -iiat portion 79 is upstanding within casing 70 and carries contact buttons 81. The two

flat portions

77 and 79 of stationary contact 76 are disposed at an angle to each other (see FIG. 15) and form a shoulder which is received within the counterbore of a hole 75 to prevent removal of stationary contact 76 through elongated hole 75. The six stationary contacts 76 are arranged in three pairs with the stationary contacts of each pair being disposed on opposite sides of an auxiliary contact carrier 88 of insulating material integral with cam follower pin 59.

I-shaped movable metallic auxiliary bridging contacts having contact buttons 86 at both ends thereof may be supported on the auxiliary contact carrier 88 and are adapted to engage the contact buttons 81 and bridge between a pair of auxiliary switch stationary contacts 76. Auxiliary contact carrier 88 is generally of box shape (see FIG. 16) and is freely slidable within an elongated guide slot 89 (see FIGS. 9, l0 and 17) in the bottom wall 74 of casing 70. A pair of rectangular cross section openings 90 (see FIGS. 14 and 16) extend laterally through auxiliary contact carrier 88, and the lI-shaped movable auxiliary bridging contacts 85 extend through openings 90 and are held on carrier 88 by compression springs 92 (see FIGS. 1l and 14) disposed within the rectangular openings 90 and urging the I-shaped contacts against the laterally extending walls defining the rectangular openings 90 in auxiliary contact carrier 88. A bridging contact 85 may be held by a compression spring 92 against either of the opposed laterally extending walls defining rectangular opening 90, thereby permitting variation of the auxiliary switch contact arrangement.

Auxiliary switch cover 73 (see FIGS. 11 and 17) tits over and closes the open end of casing 70 and has an elongated slot 94 which receives cam follower pin 59 and permits auxiliary contact carrier 88 to be reciprocated within guide slot 819 in casing bottom wall 74 by camming slot 55. The cover 73 also has indentations (see FIG. 17) which receive and support the ends 79 of auxiliary stationary contacts 76. Preferably cover 73 also has an elongated guide slot 95 (see FIG. 17), similar to slot 89 in bottom wall 73, for guiding auxiliary contact carrier 88 in a direction in quadrature with the direction of movement of main contact carrier 2G'. Cover 73 may be secured to casing 70 by headed rivets 96 (see FIGS. 9 and 17) of suitable thermoplastic material which extend through clearance apertures in these members and have the reduced diameter end deformed by heat and pressure.

Auxiliary switch S8 may be provided with three sets of double break contacts in any desired normally open or normally closed arrangement -by merely varying the stationary contacts 76 inserted in the elongated holes 75 and the movable bridging contacts 85 assembled through the rectangular openings 90 in auxiliary contact carrier 88. FIG. 12a shows an auxiliary switch having two sets of double break, normally open contacts formed by four stationary contacts 76 extending through holes 75 and cooperating with two I-shaped movable bridging contacts 85 mounted on carrier 88. In the normal position shown in FIG. 12a, main contact carrier 20I is at its lowermost position and camming surface 71 of cam slot 55 holds cam follower pin 59 in a position at the left end of its travel, wherein the contact buttons `86 on movable contacts 85 are disengaged from button contacts 81 on stationary contacts 76. In the operated position of this contactor shown in FIG. 12b, main contact carrier 20 has been actuated to its operated position and cam slot S5 has operated cam follower pin 59 to the right until contact buttons 86 on movable auxiliary bridging contacts 85 are urged against contact buttons 81 on stationary contacts 76. In the operated switch position shown in FIG. 12b, the compression springs 92 are partially loaded to maintain high pressure contact between stationary contacts 76 and movable bridging contacts 85, but such pressure is perpendicular to the direction of movement of main contact carrier and consequently the contactor electromagnet is not required to exert any force to hold the

auxiliary contacts

76 and 85 engaged. In other words, the auxiliary switch movable contacts 85 are held in engaged position by cam follower pin 59 engaging camming surface 72 of cam slot 55 parallel to the direction of movement of main contact carrier 11.

The auxiliary contact carrier 88 supporting movable auxiliary contacts 85 constitutes a free floating contact assembly which is directly and positively controlled at all times by cam follower pin 59 engaged within camming slot 55, and the normal and closed positions of auxiliary contact carrier 88 are established by the position of main Contact carrier 20. Further, all reaction force from the auxiliary switch contacts in the direction of movement of main contact carrier 20 is eliminated in the normal and operated positions of the contactor, thereby providing a constant load on the electromagnet in the operated position regardless of the contact arrangement of the auxiliary switch.

FIG. 13a: illustrates the auxiliary contact arrangement after the mounting position of auxiliary switch 58 of FIG. l2 has been reversed on contactor housing 10. It will be noted that the auxiliary switch of FIG. 12a has two normally open sets of double break contacts, whereas the same switch has two sets of normally closed contacts, as shown in FIG. 13a, after its mounting position on contactor housing 10 has been inverted. Further, such different auxiliary switch contact arrangement does not require rearrangement or reassembly of the auxiliary switch contacts. The reversal of the mounting of auxiliary switch 58 to provide a ditferent arrangement of contactsl merely requires loosening of screws `64, removal of auxiliary switch 58 from contactor housing 10, turning the switch 180, and assembling it on housing 10 so that mounting ears 62a (see FIG. 7) rather than ears 62btit beneath hook-shaped portions 61 on housing 10', and again securing switch 58 to housing 10 by means of screws 64. Camming surface 71 of cam slot 55 normally holds cam follower pin 59 in a position wherein contact buttons 86 on movable auxiliary contacts normally engage and bridge contact buttons 81 on stationary contacts 76 as shown in FIG. 13a. When contact carrier 11 is actuated to the operated position by energization of coil 18, cam slotY 55 pushes cam follower pin 59 to the right as seen in the drawing and disengages movable contacts 85 from stationary contacts 76 as shown in FIG. 13b. The camming surface 72 parallel to the direction of motion of main contact carrier 20 holds cam follower pin -59 and carrier 88 in the operated position so that the electromagnet need exert no force to maintain the movable auxiliary contacts 85 in their actuated position.

FIG. 14 illustrates an embodiment wherein auxiliary switch 58 has two normally closed and one normally open set of double break contacts. In this embodiment two I- shaped movable bridging contacts 85 protrude through the same rectangular opening in the auxiliary contact carrier 88 and are urged against opposite walls of opening 90 by compression spring 92. Reversal of the mounting position of the FIG. 14 auxiliary switch embodiment on contactor housing 10 changes the two normally closed and one normally open sets of auxiliary contacts into two sets of normally open and one set of normally closed auxiliary contacts, and such change of contact arrangement is accomplished without moving any of the switch contacts or other components. Other embodiments of auxiliary switch 58 can have one set of normally open and one set of normally closed auxiliary contacts or only one set of auxiliary contacts as desired, and such auxiliary contact arrangements are reversed when the mounting position of casing 70 on auxiliary housing 10 is inverted.

The cam slot 55 is open adjacent camming portion 72, thereby permitting withdrawal of main contact carrier 20 from housing 10 for repair and inspection without interference between the cam slot 55 and the cam follower pin 59, and also permitting reinsertion of main Contact carrier 20 into housing 10 without removing auxiliary switch 58 from housing 10.

As best shown in FIG. 7, cover 73 of auxiliary switch 58 has four protruberances 98 at the corners thereof delining slots A, B, C and DI which provide access to cam follower pin 59 and allow operation of the auxiliary switch contacts from any one of four different directions. The aligned slots B and D receive leg 21 of main contact carrier 20, whereas aligned slots A and C are narrower than slots B and D and will not fit over leg 21 and thus prevent improper orientation of auxiliary switch 5'8 when assembled on contactor housing 10.

In this preferred embodiment of the invention each leg 21 of main contact carrier 20 has a cam slot 55 for operating an auxiliary switch 58. In the embodiment of FIG. 6 each leg 21 of the main contact carrier 20 has a cam slot 55 which receives the cam follower pins 59' on two auxiliary switches and operates both auxiliary switches `as the main contact carrier 20 is moved toward the contactor cover. In such embodiment the size of the auxiliary switch mounting opening shown at 56 in FIG. l is increased to accommodate the two auxiliary switches.

Although the preferred embodiment of the invention has Ibeen described as having cam means of the cam slot and cam follower pin type with the main contact carrier having the cam surface, it will be appreciated that the invention is not so limited and also comprehends other forms of cam means as well as an arrangement wherein the cam pin is carried by the main contact carrier and is a driving element rather than a follower.

While only a few embodiments of the invention have been illustrated and described, many modifications and variations thereof will be readily apparent to those skilled in the art, and consequently it is intended in the accompanying claims to cover all such modifications and variations which are within the true sprit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An electromagnetic contactor having stationary and movable main contacts, a main contact carrier supporting said movable main contacts and being reciprocable in a direction to engage them with and disengage them from said stationary main contacts, electromagnetic means for actuating said main contact carrier, stationary and movable auxiliary contacts, cam means responsive to reciprocation of said main contact carrier for operating said auxiliary contacts between open and closed position including a first member having an inclined plane cam surface disposed at an oblique angle to said direction of reciprocation of said main contact carrier and a second member engaging said cam surface, one of said members being carried by said contact carrier and the other being operatively connected to said movable auxiliary contact, whereby the mechanical advantage provided by said inclined plane cam surface reduces the force which said electromagnetic means must provide to operate said auxiliary contacts.

2. An electromagnetic contactor in accordance with claim 1 wherein said main contact carrier is integral with said first member having said inclined plane cam surface and said second member `is a cam follower pin.

3. An electromagnetic contactor in accordance with claim 1 and including an insulating auxiliary contact carrier supporting said movable auxiliary contact and operatively connected to said other member and wherein said auxiliary contact carrier and said other member are operated by said cam means in a transverse direction perpendicular to said direction of reciprocation of said main contact carrier.

4. An electromagnetic contactor in accordance with claim 1 wherein said cam means is of the positive motion type and said cam surface has a portion parallel to said direction of reciprocation of said main contact carrier which engages said second member when said main contact carrier is actuated to its operated position by said electromagnetic means, whereby said auxiliary contacts are held operated without exerting a reaction force opposing said electromagnetic means.

5. An electromagnetic contactor in accordance with claim 3` wherein said cam surface is a cam slot having opposed wall portions adjacent one end thereof parallel to said direction of reciprocation of said main contact carrier and wherein said second member is a cam pin constrained within said slot and held between said opposed wall portions adjacent said one end when said main contact carrier is reciprocated to its operated position by said electromagnetic means.

6. An electromagnetic contactor in accordance with claim 5 wherein said main Contact carrier has said cam slot and said cam pin is a cam follower and is constrained within said cam slot.

7. An electromagnetic contactor in accordance with claim 6 and including means for guiding said auxiliary contact carrier in said transverse direction.

8. An electromagnetic contactor in accordance with claim 3 and including an auxiliary switch having aninsulating casing enclosing said auxiliary contacts and said auxiliary contact carrier and said casing has guide slot means in one wall thereof elongated in said transverse direction for guiding said auxiliary contact carrier as it is operated in said transverse direction.

9. An electromagnetic contactor in accordance with claim 3 wherein said cam surface has portions adjacent both its ends parallel to said direction of reciprocation of said main Contact carrier member one of which normally engages said second member and the other of which engages said second member when said main contact carrier is actuated to its operated position by said electromagnetic means, whereby said auxiliary contacts do not exert a reaction force on said main contact carrier in the normal and operated positions of said contactor.

10. An electromagnetic contactor in accordance with claim 9 wherein said main contact carrier is integral with said first member having said cam surface and said second member is a cam follower pin.

11. An electromagnetic contactor in accordance with claim 10 wherein said cam surface is a cam slot restraining said cam follower pin and said portions adjacent both ends of said cam surface are opposed wall portions of said cam slot and said cam slot is open adjacent said other portion of said cam surface and permits said cam follower pin to leave said cam slot without interference as said main contact carrier is moved in said direction of reciprocation, whereby said `main contact carrier may easily be removed for inspection and repair.

12. An electromagnetic contactor having stationary and movable main contacts, a main contact carrier supporting said movable main contacts and operable in a direction to engage said movable main contacts with and to disengage them from said stationary main contacts and having an inclined plane camming surface at an oblique angle to said direction of operation, a cam follower engaging said camming surface, an auxiliary switch having stationary and movable auxiliary contacts and an auxiliary contact carrier operatively connected to said cam follower and carrying said movable auxiliary contact and being operable in a directi-on perpendicular to said direction of operation of said main contact carrier to engage said movable auxiliary contacts with and disengage them from said stationary auxiliary contacts, and electromagnetic means for operating said main contact carrier, whereby the mechanical advantage of said inclined plane camming surface reduces the force which `said electromagnetic means must exert to actuate said auxiliary switch and hold it operated.

13. An electromagnetic contactor comprising an insulating housing having a` guideway therein, stationary main contacts on said housing, mov-able main contacts, a main contact carrier supporting said movable main contacts and Ibeing reciprocable in said guideway to engage said movable main contacts with and disengage them from said stationary main contacts, an electromagnet including an electric coil and a stationary magnetic core element affixed within said housing and an armature affixed to said main contact carrier and being attracted toward said stationary core element upon energization of said coil to operate said main contact carrier, an auxiliary switch mounted on said housing including stationary Aand movable auxiliary contacts, and cam means responsive to reciprocation of said m-ain contact carrier to engage said movable auxiliary contact with and disengage it from said stationary auxiliary contact and including a irst member having a cam surface disposed at an oblique angle to said direction of reciprocation of said main contact carrier and a second member engaging said cam surface,

one of said members being carried by said main contact carrier and the other being operatively connected to said movable auxiliary contact, whereby the mechanical advantage of said inclined plane camming surface reduces the force which said electromagnet -must exert to operate said auxiliary switch.

14. An electromagnetic contactor in accordance with claim 13 wherein said main contact carrier is integral with said first member having said cam surface and said second member in a cam follower pin.

15. An electromagnetic cont-actor in accordance with claim 13 wherein said cam surface positively controls said second member and has portions at both its ends parallel to said direction of reciprocation of said main contact carrier one of which normally engages said second member and the other of which engages said second member when said main Contact carrier is actuated to its operated position by said electromagnet, whereby said auxiliary contacts exert no force in the direction of reciprocation of said main contact carrier in the normal and operated contactor positions.

16. An electromagnetic contactor in accordance with claim 13 wherein said auxiliary switch includes an insul-ating auxiliary contact carrier supporting said movable auxiliary contact and being operatively connected to said other member and wherein said other member and said auxiliary contact carrier are operated in a transverse direction perpendicular to said direction of reciprocation of said main contact carrier.

17. An electromagnetic contactor in accordance with claim 15 wherein said main contact carrier has said cam surface and said second member is a cam follower pin and said cam surface is -a cam slot receiving said cam follower pin and said portions at both ends of said cam surface parallel to said direction of reciprocation of said main contact carrier are opposed wall portions of said cam slot which constrain said cam -pin when said main contact carrier is in its normal and operated positions.

18. An electromagnetic contactor in accordance with claim 13 wherein said guideway is defined by spaced p0rtions of said insulating housing providing an aperture therebetween and said second member is a cam pin and extends through said apertures.

19. An electromagnetic contactor in accordance with claim 17 wherein said guideway is defined by spaced portions of said insulating housing providing an aperture therebetween and said cam slot in said main contact carrier member is accessible through said aperture and said cam pin extends through said aperture.

20. An electromagnetic contactor in accordance with claim 19 wherein said cam slot is open adjacent said other portion of said cam surface and permits said cam pin to leave said cam slot without interference as said main contact carrier is moved in said guideway.

21. An electromagnetic contactor in accordance with claim 16 wherein said auxiliary switch includes a hollow insulating casing enclosing said stationary and movable auxiliary contacts and said auxiliary contact carrier and also including means for removably mounting said -auxiliary switch casing on said contactor housing in either of two alternate positions wherein the auxiliary -contact arrangement in one position is reversed from that in the other position.

22. An electromagnetic contactor in accordance with claim` 21 wherein said casing has guide slot means therein for guiding said auxiliary contact carrier during movement and said casing mounting means supports said casing in both of said two alternate positions so that said guide slot means directs said auxiliary contact carrier in said transverse direction perpendicular to said direction of reciprocation of said main contact carrier.

23. An electromagnetic contactor in accordance with claim 22 wherein said cam' means is of the positive motion type and has portions at both its ends parallel to said direction of reciprocation of said main contact carrier one of which normally engages said second member and the other of which engages said second member when said main contact carrier is actuated to its operated position and wherein said auxiliary contact carrier is operatively connected` to said second member rby means extending freely through a `Wall of said casing.

24. An electromagnetic contactor in accordance with claim 23 wherein said first member having `said cam surface is integral with said main contact carrier and said cam surface is a cam slot and said second member is a cam follower pin constrained within ysaid cam slot.

25. An electromagnetic contactor in accordance with claim 24 wherein said contactor housing has a recess complementary to said auxilary switch casing which removably receives said auxiliary switch casing and constitutes said means for mounting said casing on said housing in either of said two alternate positions.

26. An electromagnetic contactor in accordance with claim 19 wherein said auxiliary switch casing is a right angle prism and said contactor housing has a .rectangular recess therein in register with said aperture and cornplementary to and adapted to removably receive said auxiliary switch casing in either of two alternate positions wherein said cam pin engages said cam slot and the auxiliary switch contact arrangement in one of said two alternate positions is reversed from that in the other position.

27. An electromagnetic contactor in accordance with claim 16 wherein said auxiliary switch'includes a hollow insulating casing of right rect-angular prism configuration enclosing said auxiliary contacts and said auxiliary c011- tact carrier and having elongated guide slot means therein for guiding said auxiliary contact carrier during -movement thereof and said contactor housing has a rectangular recess therein complementary to and adapted to receive said auxiliary switch casing in either of two -alternate positions so that the longitudinal axis of said elongated guide slot means is in said transverse direction and said auxiliary switch has different arrangements of said stationary and movable auxiliary contacts in said alternate positions.

Z8. An electromagnetic contactor in accordance with claimI 27 wherein said first member having said cam surface is integral with said main contact carrier and said cam surface is a cam follower pin constrained within said cam slot.

29. An electromagnetic contactor in accordance with claim 25 wherein said auxiliary contact carrier floats freely within said casing and is held in its normal and operated positions by said opposed wall portions of said cam slot adjacent both ends of said cam slot extending parallel to said direction of reciprocation of said main contact carrier.

30. An electromagnetic contactor in accordance with claim 29 wherein a plurality of pairs of metallic stationary auxiliary contacts are upstanding within said auxiliary switch casing with the stationary contacts of each pair disposed on opposite sides of said auxiliary contact carrier and having terminal portions extending through a wall of said casing accessible from the exterior of said casing and wherein said movable auxiliary contact is an elongated metallic bridging member having contact buttons adjacent its ends and adapted to engage and bridge between the stationary contacts of at least one of said pairs of stationary contacts.

31. An electromagnetic contactor in accordance with claim 30, wherein said auxiliary contact carrier has an opening of rectangular cross section therethrough perpendicular to its direction of movement and said bridging auxiliary contact member protrudes freely through said rectangular opening and extends on 4both sides of said auxiliary contact carrier, and including a compression spring within said rectangular opening urging said movable auxiliary contact bridging member against one wall defining said rectangular cross section opening and supporting said auxiliary movable contact bridging member on said auxiliary contact carrier, whereby said movable auxiliary bridgingl contact may be disposed against either of a pair of opposed walls of said auxiliary contact carrier defining said rectangular cross `section opening to permit different arrangements of normally open and n-ormally closed auxiliary switch contacts.

32. An electromagnetic contactor in accordance with claim 26 wherein said recess and said casing are of square cross section and said auxiliary switch casing has means for preventing insertion of Said casing into said recess when it is oriented in any position other than said two alternate positions.

33. An electromagnetic contactor including an insulating housing having a recess therein, stationary main contacts on said housing, a main contact carrier reciprocable within said housing, movable main contacts supported on said main contact carrier, electromagnetic means within said housing for reciprocating said main contact carrier in a direction to engage said movable main contacts with and disengage them from said stationary main contacts, an auxiliary yswitch having an insulating casing removably positioned within said recess, stationary and movable auxiliary contacts within said casing, yand a movable member operatively connected to said movable auxiliary contact and adapted when actuated to operate said auxiliary contacts, said recess being complementary to and adapted to receive said auxiliary switch casing in either of two alternate orientations wherein said auxiliary switch has different arrangements of normally open and normally closed auxiliary contacts and means responsive to reciprocation of said main contact carrier when said auxiliary switch is in either of said alternate orientations for actuaing said movable member.

34. An electromagnetic contactor in accordance with claim 33 wherein said recess and said casing are of rectangular cross section and said auxiliary switch provides a rst contact yarrangement lwhen said casing is received in one orientation within said recess and a contact arrangement reversed from said first arrangement when -said casing is received within said recess in an orientation inverted from said rst orientation.

References Cited UNITED STATES PATENTS 2,874,244 2/1959 Hamblett 335-190 3,192,329 6/1965 Murrle.

3,238,329 3/1966 Russo 335--132 3,324,431 6/1967 Cataldo 335--132 3,359,392 12/1967 Heath.

BERNARD A. GILHEANY, Primary Examiner.

HAROLD BROOME, Assistant Examiner.