US3253092A

US3253092A - Double pole switch with reversible contact structure

Info

Publication number: US3253092A
Application number: US321093A
Authority: US
Inventors: Landow Walter
Original assignee: Clark Controller Co
Current assignee: Clark Controller Co
Priority date: 1963-11-04
Filing date: 1963-11-04
Publication date: 1966-05-24
Anticipated expiration: 1983-05-24

Description

W. LANDOW May 24, 1966 DOUBLE POLE SWITCH WITH REVERSIBLE CONTACT STRUCTURE Filed Nov. 4, 1963 INVENTOR. WALTER LANDOW Robert L. Lindgren United States Patent 3,253,092 DOUBLE POLE SWITCH WITH REVERSIBLE CONTACT STRUCTURE Walter Landow, Cleveland, Ohio, assignor to The Clark Controller Company, Cleveland, Ohio, a corporation of Ohio Filed Nov. 4, 1963, Ser. No. 321,093 11 Claims. (Cl. 200-16) This invention relates to circuit making and breaking apparatus and more particularly to a convertible pole contact block.

The apparatus of the invention is designed to positively make and break electrical circuits during repeated openings and closings of the contacts thereof over long operating periods. While single pole contact units may be employed, duplex pole units will produce the greatest flexibility and commercial advantage.

The contact block of the invention offers the advantage of compactness. It may be relatively simply installed and used in connection with AG. and DC. contactors, control relays and timing relays to electrically interlock control circuits associated with them.

The normal operative position of the movable contact elements of the unit may be easily reversed to convert the contact and the circuits controlled thereby from normally open to normally closed or vice versa. This is accomplished merely by reducing the force being applied to the movable contact element by a resilient biasing means; removing the contact element from the contact carrier; reversing the position of the movable contact with respect to the resilient biasing means; replacing the movable contact on the contact carrier; and subjecting the movable contact to the'force of the biasing means. Other than the contact element itself and the resilient biasing means, no other part of the apparatus need be disturbed to change or reverse contacts.

The separate contact units of the device are positioned on the molded housing thereof in stepped alignment. This permits visual inspection of the condition of the contacts during operation from both the front and the side of the housing, and enables wiring of the contacts from in front of the housing.

The construction of the contact device of the invention also affords safety features. The contact carrier, which is disposed for reciprocation in the housing, the contacts removably secured thereto, and the resilient biasing means associated with the contacts are constructed in a manner such that the contacts will assume their normal operative position even though the externally actuated contact carrier or the contact biasing means become damaged or broken.

Other objects and advantages of the invention shall become more fully apparent from the following drawings and the detailed description thereof:

FIGURE 1 is a front elevation of the contact device of the invention having a normally open and a normally closed contact;

FIG. 2 is an end view of the device shown in FIG- URE 1;

FIG. 3 is a side elevation of the device;

FIG. 4 is a partial front elevational view of the device of the invention illustrating the movable contact of the top contact unit of FIGURE 1 in reversed position thereby converting the unit from normally closed to normally open; and

FIG. 5 is a perspective view of a convertible contact of the invention.

As is shown in FIGURE 1, the contact device of the invention comprises a housing 1 which is molded in one piece from a high impact and electrically insulating plastic material. Melamine has been found to have these characteristics and, in addition, has good wearing qualities and is resistant to electrical tracking. The one portion of the housing is open and exposes the parts supported thereby while the other portion is closed. The exposed portion of the housing is formed with a top wall 2, a pair of generally

parallel side walls

3 and 4, a bottom wall 5 and a mid-wall 6 spaced between the top and bottom walls and extending from the side walls at an angle generally normal thereto. I

The Walls of housing 1 define an upper chamber 7 and a lower chamber 8. Top wall 2 is formed with a generally vertically extending contact carrier receiving recess 9. Mid-wall 6 is similarly constructed with an opening 10 which provides communication between

chambers

7 and 8; and bottom wall 5, as is shown in FIG. 2, also includes acontact carrier receiving slot 11. Bottom wall 5 in many of the applications of the invention is the forwardmost portion of the device and is considered the front of the device in these instances.

As may be best viewed in FIG. .3, the

side walls

3 and 4 of the housing are both formed in steps. The highest step 12 extends from top Wall 2 and step 13 extends from step 12. The terminals 14 of two pairs of fixed contacts 15 are secured to the steps of the side walls. Bottom wall 5, as shown in FIG. 2, is cut away at both its outer ends to fully expose terminals 14. This provides ready access to terminals 14, particularly from in front of bottom wall 5, but also, almost without regard to the operative position in which the device is installed.

The fixed contacts 15 extend generally laterally inwardly from terminals 14 into the

chambers

7 and 8. Each pair of these fixed contacts is positioned to project laterally into one of the chambers. The contacts lie on the same general lateral plane. They are spaced about midway between the lateral walls defining the chamber and the ends thereof are spaced apart in their respective chambers.

A contact carrier 16 is positioned for reciprocal movement in housing 1. As is shown in FIGURE 1, the outermost end of contact carrier 16 projects from the housing. The portion of the carrier adjacent this end, as is best seen in FIG. 2, lies in slot 11. From this point, the carrier extends into chamber 8 and between the fixed contacts 15, through midwall opening 10, into chamber 7 and between the fixed contacts therein and, finaly, into the recess 9 in top wall 2. The contact carrier 16 may thereby freely slide vertically in the housing.

To return the contact carrier 16 after it has been moved into contact with top wall 2, a return spring 17 is positioned in recess 9 between top wall 2 and the innermost end of the contact carrier 16. Spring 17 is retained in recess 9 by projection 18 while the end of the spring opposite wall 2 engages a centrally located projection 19 formed on the end of carrier 16 to insure proper seating of the spring with respect to the carrier.

U-shaped snap-fitting nylon retaining

clips

20 and 21 are inserted into

slots

22 and 23 of the top wall and bottom wall, respectively, of the housing. The legs of the clips are formed to engage a snap fitting provided in the molded body of housing 1, as is shown in FIG. 2. These clips serve to maintain the axial position of contact carrier 16 and to prevent other than the generally vertical reciprocating motion of the carrier with respect to the housing.

The vertical travel of carrier 16 is limited in one direction by top wall 2. Travel in the other direction is limited within upper chamber 7 by an annular shoulder 24 provided on carrier 16. Shoulder 24 is designed to contact mid-wall 6 and to act as a safety stop for the downward movement of carrier 16 in the event the carrier should break. A retaining ring 25 is secured to the lower portion of the carrier 16 in lower chamber '8 and serves to limit the downward movement of the carrier in this chamber in the same manner as shoulder 24 in chamber 7. A spring 26, which is disposed concentrically over contact carrier 16, is retained within upper chamber 7 and is free to move axially over the carrier therein. A second spring 27 is positioned In a like manner in lower chamber 8 and may move freely along the axis of carrier 16 within the chamber.

Themova'ble contact 28 of the device is clearly shown in the perspective view of FIGURE and in operating relation in FIGURES 1 and 4. The configuration of contact 28 is generally U-shaped with lateral extensions 29 projecting in opposite directions from the legs of the U. A spring seating cup member 30 is secured to the portion of contact 28 between the legs of the U. Both the movable contact 28 and cup member 30 have a generally rectangular notch 31 cut into an edge thereof. This notch conforms to the shape of

constricted segments

32 and 33 of contact carrier 16 which are respectively located in upper chamber 7. and lower chamber 8.

In order to permit the proper alignment of the movable contacts 28 with their respective fixed contacts 15, constricted segment 32 of carrier 16 in upper chamber 7 is located on a plane above that of the constricted segment 33 in lower chamber 8. This relationship is illustrated in FIG. 2. This positioning acts to align the movable contact 28 in chamber 7 at the higher level required by the elevated location of fixed contacts 15 therein while contact 28 in chamber 8 is carried at the required lower level. It also serves, as can be seen in FIG. 2, to permit easier visual observation of the condition of the contacts and to facilitate the wiring thereof.

Each of the fixed contacts 15, which is secured to the housing, is provided with a pair of contact buttons 34 which are bonded to opposite surfaces of their respective contacts. Contact buttons 35 are bonded to extensions 29 of movable contact 28. To obtain a normally closed circuit, as is shown in chamber 7 of FIGURE 1, spring 26 is manually moved using the point of a pencil or a screwdriver to the upper extremity of chamber 7 and firmly against a seat provided in top wall 2. The notch 31 of movable contact 28 is inserted into the upper constricted segment 32 of carrier 16. The contact buttons 35 of the movable contact 28 are faced to establish electrical contact with the upper fixed contact buttons 34 of the housing. When spring 26 is released, it becomes seated on cup member 30, and its position is maintained thereby. The spring, which is now seated at one end against top wall 2 and at the other against cup member 30 secured to movable contact 28, acts to maintain the contacts in their normal operative closed position.

a When the contacts of chamber 7 are in their normally closed condition, a mechanical or electro-mechanical force exerted upon the outermost end of contact carrier 16 will move the contact carrier vertically upward. The notch portion 31 of contact 28 will slide a short distance along the constricted segment 32 of the carrier. The annular shoulder 24 of the carrier will then be brought into engagement with the portion of movable contact 28 beneath cup member 30 and will overcome the forces of

springs

17 and 26 to break electrical contact. Upon release of the force exerted against carrier 16, the combined action of return spring 17 and spring 26 will restore the movable contact to its normally closed position.

To reverse the normal operative position of the movable contact 28 of upper chamber 7 with respect to the fixed contacts thereof, as is shown in FIG. 4, the spring pressure on cup member 30 is released by manually compressing spring 26 against top wall 2. Contact 28 can then be extracted from chamber 7 in a direction generally perpendicular to the longitudinal axis of carrier 16. Spring 26 is released and slid along the carrier to the opposite end of the upper chamber 7 Where it engages a seat formed in annular shoulder 24. The spring is then manually compressed against this seat to expose constricted segment 32 of the carrier. The notch 31 of movable contact 28 is inserted over the constricted segment of carrier 16 and at the end of the segment opposite which it is inserted for the normally closed contact. Contact 28 is inserted in a direction which is generally perpendicular to the axis of the carrier. The cup member 30 of the contact, upon installation, faces the end of spring 26 opposite shoulder 24, and contact buttons 35 face the bottom buttons 34 of fixed contacts 15. Spring 26 is then released and becomes securely seated upon the cup member and forces the contact member 28 into firm engagement with the portion of carrier 16 abutting the upper end of constricted segment 32. Reversal of the normal operative position of the contact is thereby accomplished by disturbing only spring 26 and contact 28, and only the contact is removed from the housing.

When the contact carrier is actuated to move upwardly, the normally open contacts shown in FIG. 4 are brought into electrical contact. The extensions 29 of contact 28 and the contact buttons 35 attached thereto have been found to produce best results when they are set at an angle of about 2 from horizontal. As the movable contact engages the fixed contacts, constricted segment 32 slides through notch 31. This causes the spring 26 to act in conjunction with the angular disposition of extensions 29 to produce a positive Wiping action on the contacts to thereby insure the reliable establishment of an electrical circuit through the contacts upon their closing. Spring 17 acts to return the movable contact 28 to its normal open position when the carrier is released.

The movable contact of the contact unit in lower chamber 8 may be initially positioned in normally open or normally closed relation to the fixed contacts therein. It may be reversed from one position to another at will and in the manner prescribed above for the contact unit of chamber 7.

When the apparatus of the invention is to be connected into a circuit, the screws of terminals 14 are loosened. This provides wire access to the area between pressure member 36 and the housing. Pressure member 36 is usually fabricated as an L-shaped stamped piece. It has been found to be highly advantageous in connecting the wires of'a circuit to terminals 14 to form member 36 with a centrally located indentation 37at the point of intersection of the legs of the L. This produces a ridge on the inwardly facing surface of member 36 which acts to engage a wire lead inserted between the member and the housing and to force it into firm electrical contact with the terminal screw. Positive electrical contact is thereby assured.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A contact device comprising a molded insulating housing open on one side, the housing being formed with first and second chambers, the chambers being separated by a common wall, the first chamber having an end wall, a pair of side walls and the common wall, the second chamber having side walls, an end wall and the common wall, a portion of the side walls of the first chamber being formed in elevated relation toward the open side of the housing with respect to the side walls of the second chamber, the end wall of the second chamber and the common wall having openings therein to receive a contact carrier, the end Wall of the first chamber having a recess in alignement with the openings to permit the reciprocal motion therein of a contact carrier, a fixed contact secured at one end to the elevated portion of a side wall of the first chamber and another fixed contact secured in like manner to the other side wall and each fixed contact extending laterally therefrom into the first chamber, fixed contacts secured to the side walls of the second chamber and extending therein, the fixed contacts of the second chamber being positioned at a level below that of the fixed contacts of the first chamber thereby permitting the connection of both groups of contacts in circuits from directly in front of the end wall of the second chamber, a contact carrier slidably disposed in the openings and the recess and extending between the fixed contacts in the first and second chambers, a pair of contact bars connected to the contact carrier, one of the bars being positioned for electrical contact with the fixed contacts of the first chamber and the other bar being positioned for electrical contact with the fixed contacts of the second chamber, and operating means associated with the contact carrier to produce the reciprocal motion thereof with respect to the 3. The contact device of claim 1 wherein the opening, in the end wall of the second chamber and the recess in the end wall of the'first chamber are provided with means to substantially prevent the movement of the contact carrier in other than the direction of the longi' tudinal axis thereof.

4. The contact device of claim 1 wherein resilient biasing means are disposed in the recess of the end wall of the first chamber between the end wall and the end of the contact carrier projecting therein to return the contact carrier and the contact bars to their normal positions upon inactivation of the operating means.

5. The contact device of claim 1 wherein the contact bar in the first chamber is positioned at a plane on the contact carrier above that of the contact bar in the second chamber to permit visual observation from a point in front of the end wall of the second chamber of the condition of the fixed contacts and contact bars, and circuit connection means disposed to the side of the contacts and generally in the plane of the corresponding contact bar to permit simple installation of circuit leads from in front of the end wall.

6. A contact apparatus comprising an insulating housing, the housing having a chamber closed on one side and open on the other and having a first end wall, a second end wall and a pair of side walls, the first end wall being formed with a recess and the second end wall having an opening in alignment with the recess to align and guide the reciprocal movement of a contact carrier therebetween, fixed electrical contacts secured to the side walls and extending into the chamber and spaced from the end walls thereof, a contact carrier positioned in the chamber between the fixed contacts, the contact carrier extending into the recess of the first end wall and through the opening in the second end wall and adapted for reciprocal motion in the chamber, a contact bar slidably disposed upon the contact carrier and removable therefrom in a direction generally normal to the longitudinal axis of the contact carrier and through the open side of the housing without removing the contact carrier from the chamber, resilient biasing means positioned on the contact carrier between the contact bar and an end wall to maintain the contact bar in one operative position with respect to the fixed contacts and to yieldably oppose the movement of the contact carrier when actuated to change the operative position of the contact bar.

7. The contact apparatus of'claim 6 wherein the fixed contacts thereof are provided with terminal elements adjacent the side walls of the housing, the first terminal element having means thereon for forcing the lead of an electrical circuit into positive electrical contact with the fixed contact, the-second terminal element having means for biasing the first element against an electrical lead.

8. The contact apparatus of claim 6 including resilient means in the recess to resiliently return the contact carrier from one operative position to another.

9. A contact apparatus comprising an insulating housing, the housing having a chamber closed on one side and open on the other and having a first end wall, a second end wall and a pair of side walls, the first end wall being formed with a recess and the second end wall having an opening in alignment with the recess to align and guide the reciprocal movement of a contact carrier therebetween, fixed electrical contacts secured to the side walls and extending into the chamber and spaced from the end walls thereof, a contact carrier positioned in the chamber between the fixed contacts, the contact carrier extending into the recess of the first end wall and through the opening in the second end wall and adapted for reciprocal motion in the chamber, a contact bar having a centrally located edge notch and slidably mating with the contact carrier and removable therefrom in a direction generally normal to the longitudinal axis of the contact carrier and through the open side of the housing without removing the contact carrier from the chamber, and resilient biasing means disposed for axial sliding movement on the contact carrier between the contact bar and an end wall and in a manner such that the biasing means cannot be removed from the carrier without withdrawal of the carrier from the chamber, the resilient biasing means acting to maintain the contact bar in a normal operative position with respect to the fixed contacts and to yieldably oppose the movement of the contact bar when actuated to change the normal operative position thereof, the normal operative position of the contact bar being reversible with respect to the fixed contacts by removing the bar from the carrier in a direction generally normal to the longitudinal axis of the carrier, sliding the biasing means on the carrier in a direction opposite its previous position and replacing the bar on the carrier and in contact with the opposite end of the biasing means.

10. The contact apparatus of claim 9 including means on the contact carrier to prevent the complete longitudinal withdrawal of the carrier from the chamber and releasable retaining clip means releasably secured to the open side of the housing and about the carrier to secure the contact carrier from withdrawal from the chamber in a direction normal to the longitudinal axis of the carrier,

the longitudinal withdrawal preventing means associated with the carrier serving to prevent the accidental removal of the resilient biasing means and the contact carrier from the chamber.

11. An electrical terminal for connecting electrical circuits comprising an electrical contact member, a plate having a pair of intersecting legs, the planes of intersection thereof defining an angle of less than and generally having an L-shaped appearance, one of the legs having a surface generally conforming to a surface of the contact member and aligned with the contact member with the opposite leg extending over the contact member, the plate being formed with an internal ridge connecting the intersecting legs thereof, and a threaded pressure member extending through the surface of the plate conforming to the contact member and threaded into the contact member, the ridge of the plate acting to force an electrical lead disposed between the plate and the contact member into positive electrical contact with the member upon the application of pressure to the plate 3,045,092 7/1962 Bundy 20016 X by the threaded pressure member. 3 047 33 7 19 2, Aushermam References Cited by the Examiner 3,170,054 2/ 1965 Lawrence et a1. 20016 X UNITED STATES PATENTS 5 2,811,617 10/1957 Townsend. KATHLEEN H. CLAFFY, Przmury Exammer.

3,018,338 1/1962 Mullen et a1. 200 -16 JAMES R. SCOTT, Assistant Examiner.

Claims

6. A CONTACT APPARATUS COMPRISING AN INSULATED HOUSING, THE HOUSING HAVING A CHAMBER CLOSED ON ONE SIDE AND OPEN ON THE OTHER AND HAVING A FIRST END WALL, A SECOND END WALL AND A PAIR OF SIDE WALLS, THE FIRST END WALL BEING FORMED WITH A RECESS AND THE SECOND END WALL HAVING AN OPENING IN ALIGNMENT WITH THE RECESS TO ALIGN AND GUIDE THE RECIPROCAL MOVEMENT OF A CONTACT CARRIER THEREBETWEEN, FIXED ELECTRICAL CONTACTS SECURED TO THE SIDE WALLS AND EXTENDING INTO THE CHAMBER AND SPACED FROM THE END WALLS THEREOF, A CONTACT CARRIER POSITIONED IN THE CHAMBER BETWEEN THE FIXED CONTACTS, THE CONTACT CARRIER EXTENDING INTO THE RECESS OF THE FIRST END WALL AND THROUGH THE OPENING IN THE SECOND END WALL AND ADAPTED FOR RE-