US2791659A - Auxiliary contact switch - Google Patents

Description

May 7, 1957 L. H. MATTHIAS AUXILIARY CONTACT SWITCH Filed Aug. 6, 1 953 *4 Baal-mega 2 Sheets-Sheet 2 INVENTOR ATTORNEY United States Patent 2,791,659 AUXILIARY CONTACT SWITCH Lynn H. Matthias, Fox Point, Wis., assignor to Allen- Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application August 6, 1953, Serial No. 372,649 11 Claims. (Cl. 200-104) This invention relates to electrical switches having a set of main contacts for opening and closing a power circuit and additional auxiliary contacts suitable for completing and interrupting control circuits carrying lesser currents and it more specifically resides in a switch having an actuator reciprocatably movable through a stroke extending between a position of rest and an actuated position for eifecting engagement and disengagement of a set of main contacts and a displaceable member supporting movable auxiliary contact means that has a portion disposed in the path of travel of said actuator to be moved therewith to engage and disengage said movable auxiliary contact means with stationary auxiliary contact means that are provided.

Electro-magnetic switches as employed for starting and stopping electric motors are frequently employed to open and close circuits in addition to those required for the control of the associated motor. This requires the provision of additional auxiliary contacts and it is particularly desirable to adapt a switch of standardized form to such applications requiring additional contacts without resort to extensive alteration of the switch. Such adaptation alleviates the necessity of the manufacture of special switches that would otherwise entail large additional expense.

It is an object of this invention to provide for the addition of contacts to a switch as the need arises without alteration of the switch, to enhance the versatility of application of the switch to varying circuit requirements.

It is another object of this invention to provide auxiliary contacts for a switch in addition to power circuit contacts that have a double break upon disengagement.

It is another object of this invention to provide auxiliary contacts for a switch in addition to power circuit contacts with a self wiping action.

It is a further object of this invention to provide sets of detachable auxiliary contacts for a switch in which each set is separately housed within a protective chamber.

It is still another object of this invention to provide a switch for control of power circuits that may have additional auxiliary contacts mounted thereon to be operated by the actuator for the power circuit contacts, which auxiliary contacts may be mounted in assembled sets by fastening with simple screw means.

These and other objects and advantages of this invention will appear in the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration and not of limitation a specific form in which the invention may be embodied.

In the drawings:

Fig. 1 is a front view in elevation with parts broken away and in section of an electro-magnetic switch embodying this invention,

Fig. 2 is a fragmentary view in section of the switch viewed through the plane 2-2 indicated in Fig. 1,

Fig. 3

is a diagram illustrating the sequence of contact engagement that occurs in the stroke of the armature of the switch shown in Fig. 1,

Fig. 4 is a rear view in elevation of an auxiliary contact assembly that forms a part of the switch shown in Fig. 1,

Fig. 5 is a view in section of the auxiliary contact assembly shown in Fig. 4 viewed through the plane Fig. 6 is a fragmentary view in section of the auxiliary contact assembly viewed through the plane 6-6 indicated in Fig. 4,

Fig. 7 is a view in section of the auxiliary contact assembly viewed through the plane 7-7 indicated in Fig. 4,

Fig. 8 is a rear view in elevation of a second auxiliary contact assembly that forms a part of the switch shown in Fig. l, and

Fig. 9 is a view in perspective of a terminal for a stationary auxiliary contact employed in the auxiliary contact assembly shown in Figs. 4-7.

Referring now to the drawings, there is shown an electro-magnetic' switch 1 having a vertical mounting plate 2 with a plurality of openings 3 suitable for securing the switch 1 to a panel or the like. Fastened to the plate 2 by rivets 4 is a field piece 5 comprising a rear bracket 6, held by the rivets 4, and a front plate 7, between which a set of stacked laminations 8 is held tightly compressed by rivets 9. A coil 10 having a central vertical opening is supported within the laminations 8 and an inverted T-s'haped armature 11 is disposed with its transverse portion 12 beneath the laminations 8, and with its shank extending upwardly and received within the central opening of the coil 10 for limited vertical travel. The transverse portion 12 of the armature it has upwardly facing pole faces 13 disposed to seat against downwardly facing pole faces 14 of the lamina tions 8 upon energization of the coil 10. A set of shading coils 15 are embedded in the pole faces 14 for the usual purposes.

An armature tongue 16, shown in Fig. 2, extends upwardly beyond the shank through a slot in the laminations 8. Secured to the tongue 16 by a pair of screws 17 is a cross bar 18 of molded insulating material that extends on both sides of the armature 11 and rests upon the laminations 8 to limit the downward travel of the armature when the coil 10 is deenergized.

A set of four uniformly spaced T-shaped inserts 19 project upwardly from the cross bar 18, and a main bridging contact 20 that is free to move upwardly and downwardly relative to the cross bar 18 is held captive by each of the inserts 19. A fiat strip coil spring 21 encircles each insert 19 and is disposed beneath the respective bridging contact 20 to urge the respective contact 20 upwardly, to maintain contact pressure in the manner hereinafter described.

The rear bracket 6 supports a molded hood 22 with a vertical rear wall 23 from the end margins of which a pair of side walls 24 extend forwardly. Evenly spaced between the side walls 24 are three vertical partitions 25 that divide the interior of the hood 22 into four contact chambers. A ceiling 26 and a front wall 27 that extends between the forward margins of the end walls 24 and the partitions 25 complete the hood 22 which is an open bottomed enclosure into which the bridging contacts 20 are moved.

A set of four angularly shaped rear terminals 28 are secured to the upper face of the ceiling 26 by bolts 29 and nuts 30. The head of each bolt 29 has mounted thereon a stationary main contact 31 that is in facing relation to a bridging contact 20. A set of four forward terminals 32 are secured to the upper face of the ceiling 26 in front of the rear terminals by means of bolts 33 and nuts 34. Each bolt 33 has a head that mounts a stationary main contact 35 in facing relation to a bridging contact 26. The stationary contacts 31 and 35 are paired, each pair being separated from adjacent pairs by a partition 25 and being disposed to be connected by a bridging contact 20 upon movement of the armature 11 and cross bar 18 upwardly in response to energization of the coil 10. I r

A pair of auxiliary contact housings 36 and 37 of molded insulating material are mounted on the front wall 27 of the hood 22 by means of mounting screws 38 that are thread'edly received in the forward terminals 32. Each housing 36, 37 extends downwardly along the front face 27 and turns rearwardly beneath the hood 22. The housing 36, which is shown in Figs. 4-7, has a lower portion in the form of a contact enclosure 39 having a pair of side walls 40, a top cover 41 and a floor 42. The rear of the enclosure 39' is open and a slotted central vertical rib 43 divides the front into a pair of right and left hand openings 4 .4. A right hand terminal 45 is inserted in the right hand opening 44, as viewed from the rear in Fig. 4, and a left hand terminal 46 is inserted in the left hand opening 44. The terminals 45 and 46 each fully close the respective openings 44 to form a front wall for the enclosure 39.

The terminal 45 is of the configuration shown in Fig. 9, where it appears that a vertical web 47 threadedly receives a terminal screw 43 and an upper flange 49 having a threaded opening 50 extends from the top margin of the web 47. From the bottom margin of the web 47 a lower flange 53 with a threaded opening 61 extends beneath the flange 49 and has a finger 52 in the form of a continuing extension upon which is mounted a stationary auxiliary contact 53. One corner of the upper flange 49 has a sharply beveled edge 54 and the lower flange 51 has a sim'larly beveled edge 55 that continues along the finger 52'. Due to the bevel the contact 53' is offset at one side of the center of the terminal 45, as clearly shown in Fig. 4. The terminal 46 is similar to the terminal 45, with the exception that the sharply beveled edges are at the opposite sides of the upper and lower flanges, and the contact 56 of the terminal 46 is ofiset on the opposite side of the terminal center line, as is clearly shown in Figs. 4 and 7. Upon insertion of the terminals 45 and 46 into the enclosure 39 the beveled edges 54, 55 of the terminal 45 will engage mating ridges in the enclosure 39 one of which is shown at 57 in Fig. 7, and the similarly beveled edges of the terminal 416 will strike similar mating ridges, one of which is shown at 53; The end of the upper flange 49 strikes the ridge 59, shown in Figs. 4 and 7 to limit the extent of the insertion of the terminal 45, and similarly the terminal 46 strikes a ridge 6d, shown in Figs. 4 and 6; Each of the terminals 45, 46 is secured inposition by a mounting screw 62 passing upwardly through the floor 42 and received in the threaded opening 6%.

One end of an actuating lever 63 is inserted in the slotted central rib of the housing 36 and is pivoted on a pin 64. The lever 63 extends rearwardly between the stationary terminals 45, 46 to project from the housing 36 with a displaceable end 65 overhanging the contact cross bar 18, as shown in Fig. 2. A spring 66 is disposed between a spring seat 6"!" on the upper side of the lever 63 and asecond spring seat 6 3 formed in the housing 36 to mo e the lever 63 to its lower position as shown in Fig. 5. An opening 69 in the body of the lever 63 receives a resilient bridging contact arm 70 that mounts a movable auxiliary contact 71 at each end in facing relation to a stationary auxiliary contact. A spring 72 also is inserted in the opening 69 with its lower end held by an ear '73 and its upper end pressing upwardly upon the underside of the bridging contact arm 70.

Referring now to Fig. 8, there is shown the auxiliary contact housing 37, which is identical with the housing, 36 and which has like designating reference numerals for like parts. The'actuating'lever in the housing 37 and the parts attached and engaged therewith are also like those of the housing 36 and like designating reference numerals have been applied to the parts shown. Inserted in the housing 37 are terminals indicated by reference numerals 45 and 46, being similar to the terminals 45 and 46, but differing from them in that they are inverted and their associated auxiliary contacts 53 and 56 are disposed above the movable auxiliary contacts 71. This manner of insertion of the terminals 45 and 46 in the housing 37 is ina sense the opposite of that employed in the housing 36. The terminal 45' is inserted in the left hand opening 44, as viewed in Fig. 8, whereas the terminal 45 is inserted in the right hand opening 44 of the housing 36 and the mounting screw 62 for the terminal 45 is threadedly engaged with the flange 49'. Similarly the terminal 46 is inserted in the right hand opening 44 and retained by an associated screw 62. It is possible to thus provide a normally open set of aux-iliary contacts as distinguished from the normally closed contacts of the housing 36, simply through rearrangement of parts. A right hand terminal 45 is converted to a left hand terminal 45 simply by inversion. Likewise terminal 46 is converted to terminal 46'. V

In Fig. 3, the vertical line 74 represents the stroke of the armature 11 and cross bar 18 in moving between the position of rest shown in Fig. 1 in which the underside of the cross bar 18 rests upon the laminations 8, and the energized position in which the pole faces 13 of the armature 11 seat against the pole faces 14 of the field piece 5. As the armature 11 is moved upwardly in response to ener'gization of the coil 10 the cross bar 18 will strike and pick up the displaceable ends 65 of the levers 63 at a point in the stroke corresponding to the line 75. Continued upward travel of the cross bar 18 swings the levers 63 about the pivot pins 64 and the normally closed auxiliary contacts in the housing 36 will open at a point in the stroke corresponding to the line 76. Next, the cross bar 18 moves the main bridging contacts 20 into engagement with the main stationary contacts 31, 35 at a point in the stroke corresponding to the line 77. The coil springs 21 are compressed between the contacts 29 and the upwardly traveling cross bar 18 to provide contact pressure. Further travel of the cross bar 18 moves the lever 62 of the housing 37 to engage the normally open auxiliary contacts at a point 78 in the stroke. The spring 72 in the housing" 37 then becomes compressed to provide Contact pressure and thereafter the armature 11 travels a sufficient distance to provide ample compression of springs 21 and 72 before the pole faces 13 seat against the'pole' faces 14 of the field piece 5.

Upon deenergization of the coil 14) the armature 11 drops to the normal'position of rest shown in Fig. 1. The sequence of contact disengagement and engagement will be'the reverse of that described for armature pickup. The normally open auxiliary contacts of the housing 37 open, followed by opening of the main contacts and then closure of the normally closed auxiliary contacts of the housing 36. As the normally closed contacts in the housing 36 are brought into engagement the bridging contact arm 79 assumes a bowed position, as in Fig. 4; to provide contact pressure and a wiping action of the contacts will occur. A similar wiping action will occur upon closure of the normally open contacts of the housing 37, due to the resiliency of the contact arm 7 0.

Additional auxiliary contact housings such as 36, 37'

may be secured to the hood 22 if desired. Or, either or both of the housings 36, 37 may be removed. Thus' a switch primarily adapted for the opening and closing of power circuits through main contacts such as 20, 31 and 35 may be employed to control additional circuits without resort to alteration or modification of the elements comprising the switch. Versatility is further en'- hanced by the provision of auxiliary contact assemblies which maybe arranged for either normally open or nor mally closed operation by a simple inversion of the terminals.

I claim:

1. In a switch the combination comprising a support carrying a set of fixed main contacts, a set of movable main contacts, an actuator for said movable main contacts adapted to move between contact open and contact closed positions, an auxiliary contact housing secured to said support, a lever having one end pivoted to said housing and extending therefrom to terminate in a displaceable end disposed within the path of movement of said actuator to be displaced thereby from a position corresponding to the contact open position of said actuator upon said actuator moving from said contact open position toward said contact closed position, said lever including an opening medial its pivoted and displaceable ends, a bias spring retained by said housing acting upon said lever to move the lever to the position corresponding to the contact open position of said actuator, a pair of stationary auxiliary contacts within said housing disposed on opposite sides of said lever, a resilient deflectable bridging contact arm inserted through the opening of said lever in bridging relation to said stationary auxiliary contacts to be engaged and disengaged therewith upon movement of said lever, and a spring hearing at one end upon said bridging contact arm urging the arm against one end wall of the opening of said lever and bearing at its other end against an opposite wall of the opening.

2. In a switch the combination comprising a support with a set of fixed main contacts, a set of movable main contacts, an actuator for said movable main contacts adapted to move between contact open and contact closed positions, an auxiliary contact housing secured to said support having a contact chamber substantially closed on both sides, the top and the bottom, a lever having one end pivoted to said housing and extending therefrom to terminate in a displaceable end disposed within the path of movement of said actuator to be displaced thereby from a position corresponding to the contact open position of said actuator upon said actuator moving from said contact open position toward said contact closed position, a bias spring retained by said housing acting upon said lever to move the lever to'the position corresponding to the contact open position of said actuator, a pair of terminals each detachably secured to said housing and having a front web to enclose the front of said chamber and a stationary contact finger extending from a margin of said web within said chamber along a chamber wall, said terminals each being reversible in position to be secured to said housing with said contact fingers alongside the bottom chamber wall or in an alternative position with said contact fingers alongside the top chamber wall, and a resilient bridging contact arm carried by said lever in bridging relation to said stationary auxiliary contacts to be engaged and disengaged therewith upon movement of said lever.

3. In a switch the combination comprising a contact mounting having a set of stationary main contacts which includes a front, sides and a top and is open at the bottom to receive movable contacts and an actuator therefor, a main contact actuator extending through the open bottom of the contact mounting with a set of movable main contacts in facing relation to said stationary main contacts having a normal position of rest and movable through a reciprocatable stroke in which said movable main contacts are engaged with and disengaged from said stationary main contacts at a point of travel medial the ends of the stroke, an auxiliary contact support with an upper attachment portion adapted to be secured to the front of said contact mounting and a depending portion turning beneath the front of the contact mounting, a lever pivoted to said auxiliary contact support having a displaceable end extending rearwardly from the depending portion thereof to within the path of travel of said main contact actuator to be displaced therewith as it moves through its stroke from said normal position of rest, a biasing spring cooperatively engaged with said lever urging the same to follow said actuator as it moves in its stroke toward said normal position of rest to a position of rest corresponding to the position of rest of said actuator, a movable auxiliary contact mounted on said lever, and terminal means adapted to be secured to the depending portion of said auxiliary contact support having a stationary auxiliary contact that may be disposed to one side of said movable auxiliary contact to be engaged thereby upon movement of said lever with said actuator from the position of rest to a position in the stroke beyond that at which said main contacts engage, which terminal means may in the alternate be disposed with said stationary auxiliary contact to the opposite side of said movable auxiliary contact to be engaged therewith when said lever is in said position of rest and disengaged therewith upon movement of said lever with said actuator against said biasing spring at a point in the stroke before engagement of said main contacts.

4. in a switch the combination comprising a contact hood open at the bottom which has a set of stationary main contacts; an actuator beneath the open bottom of the contact hood having a position of rest and movable in a stroke away from and back toward said position of rest; a set of movable main contacts mounted on said actuator in facing relation to said stationary main contacts and engaged and disengaged therewith at a position in the stroke of said actuator medial the position of rest and the position at the opposite end of the stroke; an insulating support with an upper attachment portion adapted to be fastened to the hood and a depending portion extending downwardly and turning beneath the hood; a lever supported by the insulating support having a displaceable end in the path of travel of said actuator to be displaced thereby; biasing means mounted by said insulating support for said lever urging the displaceable end toward the position of rest of said actuator; a bridging contact having deflectable resilient arms supported by said lever, a spring retained at one end by said lever and working against said bridging contact at its opposite end to normally hold said bridging contact against a portion of said lever and permitting said bridging contact to move against said spring; and a set of stationary auxiliary contacts mounted by the depending portion of the insulating support in facing relation with said bridging contact to be connected thereby and disconnected therefrom upon said actuator moving through its stroke.

5. In a switch the combination comprising a contact hood open at the bottom which has a set of stationary main contacts; an actuator beneath the open bottom of the contact hood having a position of rest and movable in a stroke away from and back toward said position of rest; a set of movable main contacts mounted on said actuator in facing relation to said stationary main contacts and engaged and disengaged therewith at a position in the stroke of said actuator medial the position of rest and the position at the opposite end of the stroke; an insulating support with an upper attachment portion adapted to be fastened to the hood and a depending portion extending downwardly and turning beneath the hood; a lever supported by the insulating support having a displaceable end in the path of travel of said actuator to be displaced thereby; biasing means mounted by the insulating support for said lever urging the displaceabie end toward the position of rest of said actuator; a stop on said insulating support limiting movement of said lever in response to said biasing means to fix a position of rest for said lever with the displaceable end thereof spaced from the position of rest of said actuator; a bridging contact having resilient arms received by said lever, a spring seated at one end by said lever and working against said bridging contact at its opposite end to normally hold said bridging contact against a portion of said lever and permitting said bridging contact to move against said spring; and a set of stationary auxiliary contacts mounted by the insulating support in facing relation with said bridging contact to be connected thereby and disconnected therefrom upon said actuator moving through its stroke, said stationary auxiliary contacts being disposed in a position to be engaged upon movement of said lever with said actuator from the position of rest to a position in the stroke beyond that at which said main contacts engage, or in the alternative, in a position to be engaged with said bridging contact when said lever is in said position of rest and disengaged therewith upon movemnet of said lever to a point in the stroke before engagement of said main contacts.

6. In a detachable auxiliary contact switch for a main switch with stationary and movable contacts and an actuator for causing contact engagement and disengagement, the combination comprising an insulating support adapted to be detachably secured to such a main switch formed to provide a pair of contact compartments with orientating surfaces; a pair of terminals each adapted to be inserted within either of said contact compartments and having a web with an exposed connector for affording electrical connection, a pair of upper and lower flanges extending from the top and bottom margins of the Web into the respective compartment, a fixed contact mounted on one flange facing the opposite flange, and orientation surfaces engageable with the orientating surfaces of the respective compartment for positioning the terminal with respect to the compartment whereby said terminals may be inverted to dispose the respective contacts toward the bottom or in the alternative toward the top of the compartments; attachment means received by each of said compartments and engageable with a flange of each terminal to fix the same in position; a lever pivoted at one end to said support and extending therefrom to be actuated by the actuator of a main switch upon attachment of said support thereto; and a bridging contact carried by said lever with contact arms in facing relation to the contacts of said terminals for engagement and disengagement therewith.

7. In a detachable auxiliary contact switch for a main switch with stationary and movable contacts and an actuator for causing contact engagement and disengagement, the combination comprising an insulating support adapted to be detachably secured to such a main switch providing a housing closed at the sides, top and bottom and having right and left hand compartments; a pair of terminals adapted to be secured to said insulating support each having a web enclosing the front of one compartment, a pair of flanges within the respective compartment that extend from the top and bottom of the web, and a fixed contact mounted on one flange of the terminal facing toward the other flange, said terminals being reversible in position whereby each may be inverted and placed in the opposite compartment to dispose the respec tive contacts toward the bottom or in the alternative toward the top of the compartments; attachment means through the bottom of said housing securing the lowermost flange of each terminal to the housing; a lever passing through the interior of the housing separating the same into said right and left compartments pivoted at one end to said support and extending therefrom to be deflected at the opposite end by the actuator of a main switch upon attachment of said support thereto; and a bridging contact member carried by said lever at a point between the ends thereof with resilient deflectable contact arms extending into each compartment for engagement and disengagement with said terminal contacts.

8. in a detachable auxiliary contact switch for a main switch with stationary and movable contacts and an actuator for causing contact engagement and disengagement the combination comprising an insulating support adapted to be detachably secured to such a main switch with a pa of horizontally spaced right and left hand terminal receiving portions, each portion presenting terminal orientating surfaces; a first terminal including a central web with top and bottom margins, a flange extending from one margin of said web with a fixed contact offset to one side of the terminal and orientation surfaces adapted to mate with the orientating surfaces of said insulating support whereby said terminal may be inserted in either the right or left hand terminal receiving portion but is restricted such that an inversion is required when being taken from one portion and placed in the other whereby said contact is disposed toward the top and the outside when in the right hand terminal receiving portion and toward the bottomand outside when in the left hand terminal receiving portion; a second terminal including a central web with top and bottom margins, a flange extending from one margin of said web with a fixed contact olfset to one side of said terminal, and orientation surfaces forming a part of said terminal adapted to mate with the orientating surfaces of said insulating support whereby said terminal may be inserted in either the right or left hand terminal receiving portion but is restricted such that an inversion is required when being taken from one portion and placed in the other whereby said contact is disposed toward the bottom and outside when in the right hand terminal receiving portion and toward the top and outside when in the left hand terminal receiving portion; attachment means adapted to retain said terminals in orientated position with respect to said terminal receiving portions of said support; an operating member carried by said support and extending therefrom to be actuated by the actuator of a main switch upon attachment of said support thereto; and a deflectable bridging contact arm carried by said operating member extending between the contacts of said terminals for engagement and disengagement therewith.

9. in a detachable auxiliary contact switch for a main switch with stationary and movable contacts and an actuator for actuating the movable contacts the combination comprising an insulating support adapted to be detachably secured to such a main switch with a pair of horizontally spaced right and left hand terminal receiving portions, each portion presenting terminal orientating surfaces; a first terminal including a central web with top and bottom margins, a first flange extending from one margin of said web with a fixed contact oflset to one side of said terminal, a second flange extending from the other margin of said web, and orientation surfaces adapted to mate with the orientat'ing surfaces of said insulating support whereby said terminal may be inserted in either the right or left hand terminal receiving portion but is restricted such that said contact is (lisp sed toward the top and the outside when in the right hand terminal receiving portion and toward the bottom and outside when in the left hand terminal receiving portion; a second terminal with a central web with top and bottom margins, a first flange extending from one margin of said web with a fixed contact offset to one side of said terminal, a second flange extending from the other margin of said web, and orientation surfaces adapted to mate with the orientating surfaces of said insulating support whereby said terminal may be inserted in either the right or left hand terminal receiving portion but is restricted such that said contact is disposed toward the bottom and outside when in the right hand terminal receiving portion and toward the top and outside when in the left hand terminal receiving portion; attachment means adapted to engage the lowermost flange of each terminal to said support; an operating member pivoted at one end to said support and extending between said terminals to a deflectable end for movement by the actuator of a main switch; and a resilient deflectable bridging contact arm carried by said operating member extending between the contacts of said terminals for engagement and disengagement therewith.

10. In a detachable auxiliary contact switch for a main switch having a contact hood with top, sides, back and front that is open at the bottom; stationary contacts within the hood; movable contacts; and an actuator beneath the hood supporting the movable contacts movable toward and away from the stationary contacts, the combination comprising an insulating support with an upper attachment portion adapted to be fastened to the front of the hood of a main switch and a depending portion to turn beneath the front of the hood which forms a housing and is closed at the sides, bottom and top; terminal means enclosing the front of said housing presenting fixed contacts within the housing; a lever pivoted at the forward end to said housing at a point to the front of said fixed contacts extending rearwardly of said housing into the path of travel of the actuator of the main switch to which the auxiliary contact switch may be attached; a bias spring carried by said housing urging said lever to pivot in a direction corresponding to Contact open position of an actuator; and movable contact means carried by said lever in facing relation to said fixed contacts within the housing.

11. In a detachable auxiliary contact switch for a main switch the latter having a contact hood with a top, sides, back and front that is open at the bottom; stationary contacts within the hood; movable contacts; and an actuator beneath the hood supporting the movable contacts which is reciprocably movable between normal and actuated positions; the combination comprising an insulating support with an upper attachment portion adapted to be fastened to the front of the hood of the main switch and a depending portion to turn beneath the front of the hood which includes an auxiliary contact housing; terminal means accessible from the exterior of the housing and extending to within the housing to present fixed auxiliary contacts therein; a lever pivoted to said insulating support and extending rearwardly of said housing into the path of travel of the actuator of the main switch to be operatively engaged thereby; a bias spring carried by said insulating support urging said lever to pivot in a direction corresponding to normal position of the actuator; and movable contact means carried by said lever in facing relation to said fixed auxiliary contacts within the housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,190,299 Van Valkenburg Feb. 13, 1940 2,239,031 Bierenfeld et al Apr. 22, 1941 2,295,577 Hammerly Sept. 15, 1942 2,297,339 Wilms et a1 Sept. 29, 1942 2,360,670 Goetz Oct. 17, 1944 2,481,431 Logan Sept. 6, 1949 2,500,181 Hubbell et al Mar. 14, 1950 2,545,986 Basnett Mar. 20, 1951 2,585,824 Noyes Feb, 12, 1952 FOREIGN PATENTS 120,261 Sweden Nov. 25, 1947 633,396 Great Britain Dec. 12, 1949

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