US2874252A

US2874252A - Electric switch

Info

Publication number: US2874252A
Application number: US713259A
Authority: US
Inventors: Lyle J Wenzel; Ernst R Wolff
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1958-02-04
Filing date: 1958-02-04
Publication date: 1959-02-17
Anticipated expiration: 1976-02-17

Description

Feb. 17, 1959 L. J. WENZEL EI'AL 2,874,252

ELECTRIC swncn Filed Feb. 4, 195a INVENTORS LYLE J. WENZEL, ERNST R. WOLF-F A TTDRNE Y tact movement.

2,814, ELECTRIC SWITCH Lyle]. WenzehNormal, and ,Ernst .R. Wolff, Bloomington, Ill., .assignors to General Electric Company, a corporation of New York Application February 4, ,:1'95-8,:Serial No. 713,259 10 Claims. (Cl. 200-166) Our invention relates 'to 'electricswitches and in :particular to that type of electric switch which is constructed to provide either normally open or normally closed contact operation.

In general, prior, art switches of this type have re-' quired that the switch enclosing case be dismantled and that the contacts be manually reversed. This necessity for disassembly requires morecomplex structures and methods of construction and often results in increased size merely to provide the normally open to normally closed reversible feature.

In addition, attempts to adapt these prior art switching devices for use .as auxiliary :contacts or interlocks with electromagnetic 'fstarters .have usually produced switches which are bulky, difficult to operate, and not possessing the reliability of the contactor itself. For example, such prior art devices have generally been designed to provide the same amount of interlock .switch actuator travel as main contactor actuator travel thereby requiring .a large switch which is complicated .by the reversible contact feature. switch to cooperate properly with the magnetic contactor it is desirable that it be :small -in size, easily installed and removed, and :that ,it qhave reliability and ease of operation at least equivalent to that of the magnetic contactor.

It is therefore an object of this invention to provide an electric switch whose mode of contact operation can be reversed from normally open to normally closed without dismantling the switch enclosing case or the switch contacts.

Another object of this invention is to provide a switch which is small in size, easily manufactured with liberal tolerance both in assembly and -munting,and which provides economy of manufacture without sacrificing reliability of operation; It :is .a further object of this invention to provide an electric switch which utilizes only simple stamped andrno'lded parts for its major components While achieving the desired small size and reliability. y

It is a still further object. of this invention to provide a switch having external indicating means which will positively identify the unoperated or normal position of the switch contacts. a

In accordance with ;a. preferred form of our invention, a switch is provided having a two piece molded insulating housing which supports the switch contacts and external terminals and which has an opening along two sides to admit and provide for movement of a contact actuator. The contact actuator has preformed cam surfaces thereon which engage a cam follower surface on one of the contact support structures. Movement of'this actuator brings the cams into engagement with the contact support structure so as to regulate the con- The reversibility from normally open to normally closed operation is simply obtained by the withdrawal and end-for-end reversal of the contact actuator.

In order for the auxiliary Ratented Feb. 17, 1959 These and other. novel features believed characteristic of the invention are set .forth in the appended claims. The construction of a preferred embodiment of thisiinvention together with further objects and advantages thereof may :be easily understood, however, from the following description taken :in conjunction with the accompanying :drawings in which,

. Figure 1 :lS an end view of 'an electromagnetic contactor with :the switch in combination therewith;

Figure 12 is a :side "view :of 1 the switch with one part :of the housing removed and the actuator arranged to provide normally open contact operation;

Figure .3 :is asside view of 'ihe switch with :one :part of the housing removed and the :actuator arranged to 'provide normally closed contact operation;

Figure 4 is':a:latera1rcrosszsection of the switch taken along Ethe line A-A of :Figure 1', and p Figure 5 is an -'expl'oded view of 'a preferred embodiment :of :this invention.

Referring now ."Figure 1, the magnetic contactor .10 shown 'in dotted :lines is representative of typical devices which can be utilized to actuate the switch of this invention ;and is :more fully described in the co-pending applicationSer'ial No. 686,318 by James Burch and assigned to the assignee :of :the present invention. The switch 11 -.is secured'to amounting .plate 12 by the screws :13. The mounting plate :12 is fastened .to the frame of "the magnetic 'contactor lll sosas to position the switch 11 and its operating arm :14 for proper actuation by the projection 15 on the movable :member of the magnetic contactor.

The terminal 316, stamped from a suitable conducting material, has ascrew fastener 17 at its outside end for accommodating the connection of a wire and has a 'conductive :spring strip 18, made from materials such as Phosphor bronze, attached by suitable means to its internal end. The strip 18 carries 'a contact 19 near the other end portion, which portion engages a shoulder-20 which is molded in the insulated housing 21. The terminal member '22, stamped .from :a suitable conducting material, also has a screw fastener 17 in its'external end and has a spring :strip 23 connected to its internal 'end.

The spring strip 23 has .a deformity or cam follower 24 formed intermediate its ends and has the contact 25 appropriately fastened at its free :end. As is seen in the drawings, and particularly Figure 4, the terminal strip 16 and terminal strip .22 are held between the

mating halves

21 and 26 of the housing through the engagement of the projections 27 and 28 in the slots '29 and 30. These slots and projections serve to retain and position the terminal strips and'are assisted in this funcition by the-engagement of the walls of the slots formed in each half of the housing to admit the terminals.

The contact actuator shown generally at 31 has

projections

32, 32a, 33 and 33a which engage slots 34 in the casing member 21 and 35 :in the casing member 26. This mating projection and slot arrangement guides the switch actuator 31for longitudinal movement. The

end projections

36 and 37 on actuator 31 serve to indicate the unoperatedor normal position of the contacts 19 and 25 v(as will be herein-after explained) and also engage the spring 38'which biases the actuator 31 into the position shown in Figures 2 and 3. The spring 38 is retained in position by the shoulder 3% and 49 of the

enclosure members

21 and 26 and the engagement of the

tabs

36 or 37 with the spring member 38 serve to positively position the switch actuator relative to the spring.

The operating lever 14, -is secured to the actuator by the screw 42 which passes through the aperture 43 to engage the threaded opening44 in the actuating lever. The -.cylindrical projections 45 and 46 (or 45a and 4601) engage the

apertures

47 and 48 therebypositively posihousing 21 tioning the actuator arm relative to the contact actuator.

As clearly shown in Figure 4, the operating arm 14 has an offset portion terminating in a bent-up tab 41. The

:offset portion of the arm properly positions the tab 41 .relative to the operating projection 15 of the associated magnetic contactor (see Figure 1) so that the operating force can be properly applied to the switch.

rivet 50.

Referring particularly to Figure 5, it is seen that the 4 slots 34 and 35 'in the

housing members

21 and 26 extend to one edge of the housing. The slot 51 in the extends from the slot 34 to the outside face of the housing and is dimensioned to partially define an opening equal in size to the projection 33a. The slot 52 also partially defines an opening equal in size to the projection 33, such opening extending from the slot 35 in the housing member 26 to the outside edge. The distance A between the

projections

32 and 33 is substantially equal to the distance A between the edge of slot 51 and the end of the housing. Withthe case thus dimensioned relative to the projections on the contact actuator, it can be seen that the actuator 31 may be inserted into the housing bymoving it laterally so that the

slots

52 and 51 mate with the

projections

33 and 33a thereby placing the

projections

32 and 32a external to the edge of the housing. Alternatively, end 37 of actuator 31 may be inserted into the housing front adjacent the open ends of

slots

34 and 35. Once the actuator has been so inserted into the housing, it may be moved longitudinally with the

projections

32, 32a, 33, 33a in proper engagement with the

slots

34 and 35.

Referring particularly to Figures 2 and 3, it is seen that the contact actuator has two projections or

cams

60 and 61 which extend into the switch housing. Figure 2 shows the spring 38 is expanded to its full dimension so that the contact actuator is in its normal or unoperated position. In this position, the cam follo'wer 24 is positioned between the two

cams

60 and 61 thereby allowing the spring force of the arm 23 to produce an open contact relationship between the contacts 19 and 25. As the contact actuator 31 is moved in the direction of the arrow, the cam surface 61 is moved in the direction of the arrow and engages the cam follower 24 thereby forcing the contact 25 into engagement with the contact 19. When the force is removed from the operating arm 14, the spring returns the actuator to its normal or rest position allowing the contacts to open.

Figure 3 shows the contact actuator 31 reversed endfor-end from that of Figure 2 so that the normal or rest position of the contact actuator places the cam surface 60 in engagement with the cam follower 24 thereby forcing the contacts into engagement. Because the spring is in its normal unoperated position, the contact actuator establishes a normally closed contact relationship when the contact actuator has the orientation shown in Fig. 3. Movement of the contact actuator in the direction of the arrow disengages the cam surface 60 from the follower 24 allowing the normal spring bias of the contact arm 23 to open the contacts.

The slope and size of the

cam surfaces

60 and 61 can be dimensioned and designed to produce any desirable contact tip velocity. 7

As is seen in the drawings, the rest position of the contact actuator 31 places either

tab

36 or 37 in view external to the housing depending on the orientation of the contact actuator. This tab portion while performing the alternate function of engaging the spring, carries appropriate indicia shown at 70 and 71 to indicate the norin said housing at one end of said mal or rest position of the contacts. The portion of the actuator which extends laterally beyond the housing can also carry

indicia

72 and 73 to indicate the unoperated contact position by virtue of their position opposite the arrow 74 on the housing 26.

To reverse the orientation of the actuator end-forend and thereby change from normally open to normally closed contact operation, it is necessary to move the actuator 31 to the left (see Figure 5) until the

tabs

33 and 33a are lined with the

slots

51 and 52. This position also places the

tabs

32 and 32a external to the switch housing so that the actuator may be laterally with drawn therefrom. Removal of the screw 42 permits the operating arm 14 to be given a one-half revolution and mounted on the opposite side of the contact actuator 31. The

cylindrical projections

45, 46 or 45a, 46a on the contact actuator 31 engage the

apertures

47 and 48 in the actuator thereby positioning the operating arm 14 relative to the actuator 31. The actuator is then reinserted into the housing and depressed until the tab 36 is engaged with spring 38. The switch is then in condition for operation in a normally closed position as shown in Figure 3. This reversal feature has been accomplished without dismantling the housing or disturbing the contact arrangement.

When this switch is associated with a magnetic contactor as shown in Figure l, the actuator arm 14 is positioned so that its rest position is displaced by the amount D from the rest position of the contactor actuator projection 15. When the contactor is actuated, the projection 15 must travel the distance D before it engages the operating arm 14 and thus a smaller travel distance is required for the contact actuator than for the movable arm of the magnetic contactor. This reduced distance of travel permits the over-all size of the auxiliary switch member 11 to be considerably reduced in size and allows the contactor magnet to start up with out the additional load of an auxiliary switch at the initiation of travel.

The improved switch structure enables the switch to be changed from normally open to normally closed contact operation without disturbing the magnetic contactor. It is merely necessary to withdraw the actuator 31 from the housing, reverse the switch actuator as was previously described and then reinstall the actuator 31 within the housing and the switch is .ready for operation on the contactor frame.

It will thus be seen that we have provided a switch which can be used as an auxiliary contact or interlock for a magnetic contactor or similar application, which is small in size, which contains very few parts, and which provides simple, rugged and extremely reliable operation. Further, this improved switch enables either normally open or normally closed contact operation to be provided without the structural dismantling of the switch housing. All that is required to reverse the contact operation is the withdrawal and reversal of the contact actuator and the reversal of the contact actuator arm.

Although we have described a particular embodiment of our invention, many modifications may be made. It is to be understood that we intend by the appended claims to cover all such modifications that fall within the true spirit and scope of the invention.

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

1. A switch comprising a housing having an elongated aperture therein, a pair of contacts within said housing having electrical connections extending outside of said housing, means for biasing at least one of said contacts away from the other of said contacts, an elongated movable contact actuator positioned in said elongated aperture and movable longitudinally therein, a captive spring withaperture for urging said contact actuator toward a normal position in said housing, said contact actuator being removable through the end of said elongated'aperture opposite said captive spring and reinsertable therein with a reversed end-to-end orientation, said contact actuator having cammed surfaces on longitudinal surfaces thereof, said cammed surfaces being positioned when said actuator has a first orientation relative to said housing to close said contacts against the force of said biasing means upon movement of said actuator from said normal position against the force of saidv captive spring and to permit said biasing means to open said contacts from a normally closed position upon movement of said actuator against the force of said captive spring when said actuator has a second orientation reversed end-to-end from said first orientation.

2. The switch set forth in claim 1 wherein said switch housing has a longitudinal aperture therein extending along a portion of two sides, and said contact actuator has a portion thereof extending laterally through said aperture beyond the edges of said housing and has an operating arm mounted on said laterally extending portion, said arm being detachably secured to said actuator so that it may be reversed in position when said actuator is reversed thereby maintaining the relative position of said operating arm and said housing the same.

3. The switch set forth in claim 1 wherein said housing has an aperture provided at one end and said actuator has a portion extending beyond said housing through said aperture when said actuator is in the unoperated position, said projection having indicia thereon to indicate the circuit relationship of said contacts? when said switch is in the unoperated position.

4. The switch set forth in claim 1 including a spring positioned at one end of said housing and an additional projection at each end of said contact actuator, said projections being dimensioned to engage said spring and having indicia thereon to indicate the condition of, the contacts whereby positioning said actuator to engage one said end projection with said spring allows said other end projection to extend beyond said housing to indicate the unoperated condition of said contacts.

5. A switch comprising a two piece molded insulating housing whose mating sides'define a longitudinal aperture, a pair of contacts within said housing having electrical connectors extending outside of said housing, means for biasing at least one of said contacts away from the other, a longitudinally movable contact actuator having a portion which extends laterally through said longitudinal aperature to which the operating force is applied, and a spring biasing said actuator into an unoperated position, said actuator having an irregular longitudinal surface which engages said biased contact whereby movement of 6 and one end mounted on said second terminal within said housing, a second contact mounted at the other end of said second leaf spring, said first and second leaf springs being mounted to place said contacts in opposite but displaced relationship, and a contact actuator mounted for sliding movement within said housing and having a portion extending through said longitudinal aperture, said actuator having a cam surface thereon engaging said cam said actuator from its unoperated position will close said contacts when said operator is in a first position and will open said contacts when said actuator is in an end-for-end reversed position.

6. The switch of claim 5 wherein said longitudinal aperture extends into the top of said housing and said contact actuator has a projection at each end, each said projection dimensioned to engage said actuator bias spring, said projections having indicia thereon whereby the unoperated condition of said contacts is indicatedex- .ternal to said housing.

7. An auxiliary switch for an electromagnetic contactor comprising a split housing whose mating halves define a longitudinal aperture which extends along two sides of said housing, first and second terminals external to said housing, each having a portion extending into said housing, a first leaf spring having one end mounted on said first terminal within said housing, a first contact mounted at the other end of said first leaf spring, a second leaf spring having a cam follower intermediate its ends follower on said second leaf spring whereby movement of said actuator in one position moves said contacts from the open to the closed position and movement of said actuator in an end-for-end reversed position allows said contacts to move from the closed to the open position.

8. A switch comprising a two piece molded insulating housing whose mating sides define a longitudinal aperture, a pair of contacts within said housing having electrical connectors extending outside of said housing, an elongated movable contact actuator positioned for sliding movement in said aperture, said contact actuator having first and second spaced projections on a longitudinal surface thereof, said projections being positioned to close said contacts from a normallyv open position upon actuator movement when said actuator has a first orientation relative to said housing and to open said contacts from a normally closed position upon actuator movement when said actuator has a second orientation reversed end-to-end from said first orientation, a captive spring mounted within said housing at one end of said elongated aperture for engaging said contactor at one end and biasing it toward a normal position, said contact actuator being removable through the opposite end of said elongated aperture for reversal of its orientation.

9. A switch comprising a two piece molded insulating housing whose mating sides define a longitudinal aperture, a pair of contacts within said housing having electrical connectors extending outside of said housing, an elongated movable contact actuator positioned for sliding movement in said aperture, said contact actuator having first and second spaced projections on a longitudinal surface thereof, said projections being positioned to engage at least one of said contacts and to move it in a direction substantially normal to the direction of movement of said actuator to close said contacts from a normally open position upon actuator movement when said actuator has a first orientation relative to said housing and to open said contacts from a normally closed position upon actuator movement when said actuator has a second orientation reversed end-to-end from said first orientation, a captive spring mounted within said housing at one end of said elongated aperture for engaging said contactor at one end and biasing it toward a normal position, said contact actuator being removable through the opposite end of said elongated aperture for reversal of its orientation.

10. The switch of claim 1 wherein said longitudinal aperture extends laterally along the side of said housing with slots formed in said housing for the guidance of said contact actuator, said contact actuator having lateral pro.- jections engaging said slots and wherein said housing has an enlarged portion in said longitudinal opening to permit lateral withdrawal of said contact actuator from said housing when said actuator projections are aligned with said enlarged portion of said longitudinal aperture.

References Cited in the file of this patent UNITED STATES PATENTS 2,419,072 Hall Apr. 15, 1947 2,545,986 Basnett Mar. 20, 1951 2,811,617 Townsend Oct. 29, 1957 2,822,450 Goudy et al. Feb. 4, 1958