US2715715A - Clamp-type wire terminal with insulating housing - Google Patents

Description

Aug. 16, 1955 R. H. BENTLEY CLAMP-TYPE WIRE TERMINAL WITH INSULATING HOUSING Filed 001;. l, 1953 INVENTOR. RoZSerZIi. Beztfilv fiEfo-r Patented Aug. 16, 1955 eLAMP-TYPE wins TERMINAL WITH INSULATiNG HOUSING Robert H. Bentley, Hartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application October 1, 1953, Serial No. 383,558

7 Claims. (Cl. 339-216) This invention relates to terminals for electric wiring devices such as attachment plug receptacles, switches and the like. More particularly it relates to wire terminals known as clamp-type terminals as disclosed in the patent of T. W. Shenton 2,262,712, dated November 11, 1941, a general familiarity with which will be assumed. In such terminals, the bared end of a conductor wire can be inserted in unbent condition between a movable member and clamped between it and a fixed member by tightening a screw; or the wire end can be wound around the shank of the screw beneath its head and secured in the usual fashion as the screw is tightened.

Heretofore in clamp-type terminals difiiculty was encountered as the screw was turned and backed out so far as to become disengaged from the clamp member. The clamp member being loose or floating in the cavity in which it operated could, and commonly did, have its screw threaded hole get out of register with the hole in the fixed member through which the screw shank freely passed. On attempting to re-engage the screw in the tapped hole of the clamp, it was ditiicult almost to the point of impossibility to get the clamp and screw together and the screw started turning into the hole in the clamp.

Not only did the difiiculty in getting the screw in register with and started turning into the top hole in the clamp member provide the difiiculties when the device was in use and while it was being installed but it also gave considerable difficulty and posed additional and unnecessary problems in the assembly of the terminal parts in the base of the device while being manufactured and assembled. Special provision had to be made to get the screw threaded into the clamp member at certain stages in the assembly procedure; or special provisions had to be made to maintain the register of the clamp and stationary terminal member so that the screw could be inserted after the device was otherwise completely assembled. Both these provisions required additional time and raised the cost of manufacturing.

Therefore it is an object of this invention to provide in a clamp-type terminal a novel combination of clamping member with its stationary terminal member which will facilitate engagement of the screw with the clamp during original manufacture and assembly as well as later in use.

Another object is to provide in a clamp-type terminal a permanent mounting of the clamp member in the stationary terminal member with which it cooperates, which will not impair the clamping function of the clamping member or the terminal member but which will facilitate assembly into the device during manufacture, and which will enable immediate engagement of the screw in the clamp on insertion through the hole in the stationary member.

Other objects and advantages in the invention will become apparent as it is described in connection with the accompanying drawing.

In the drawing:

Fig. 1 is a detail perspective view of a clamp-type terminal embodying the invention.

Fig. 2 is a fragmentary plan view of the terminal of Fig. 1 inserted in one corner of the base of a wiring device.

Fig. 3 is a side elevation view of the terminal of Fig. 2.

Fig. 4 is a section view taken along line 44 of Fig. 2.

Fig. 5 is a detail perspective view of another form of clamping member.

Referring to the drawing, the invention is illustrated as applied to a combined switch contact member and wire terminal but it may be just as well applied to an attachment plug contact terminal or other electric device terminal.

The terminal is located in one corner of a hollow insulating base 14) in which it may be mounted in any suitable fashion as by slipping with a rectilinear motion from front to back or top to bottom. For that purpose slots 12, 14 are provided running from front to rear direction adjacent the side and end walls 16 and 18 of the corner respectively. By fitting the end edges of the terminal member in the slots, the terminal may be slid in place readily.

The terminal comprises three main parts; a stationary metallic stamped sheet metal member 2%, a stamped sheet metal clamp member 3% loosely hingedly mounted on the stationary member 20, and a binding screw 40.

The stationary member 2% is stamped into right angular or L-shape providing a fiat side plate 22 lying flush against the inside surface of the side wall 16 of the insulating base, and a flat end plate 24 lying parallel to, but slightly spaced from the end wall 18 of the insulating base. A rib 18 running from front to rear is formed on the inside surface of the end wall 18 to space the terminal end plate at one side from the base end wall, while an equivalent protruding corner or rib 18" is formed running from front to rear adjacent the other side of the end plate to space it from the end wall 18.

The clamping member 30 is, or may be stamped into arcuate transverse cross section in order that its edges nearest to the stationary member 20 may bite into or more firmly grip the bared end of a conductor wire 44. Into the clamp member is tapped a hole 32 to receive a binding screw 40 whose shank passes freely through an aperture 21 in the side plate 22 of the stationary member which aperture is in register with the tapped hole in the clamp. The shank is long enough so that a conductor wire can be wound around the shank under the head of the screw for side wiring of an electric device; or the bared end 44 can be inserted through a hole 17 in the floor 19 of the insulating base 10 and clamped between the clamp 30 and side plate 22 by turning the screw.

To guide the movement of the clamp toward and from the side plate 22, the bottom edge of the clamp may slide over the floor of the base while the top edge may be guided by a lug 23. The lug 23 is formed as an extension from the upper edge of the side plate 22 and is bent at a right angle inwardly therefrom. In order for the lug also to serve to limit the extent to which the bared conductor end 44 can be inserted, the lug is located directly above the hole 17 in the floor.

In order to prevent the clamp member from getting out of proper location and to maintain the tapped hole of the clamp in register with the aperture 21 in the side plate, the clamp member is hingedly mounted in the end plate 24 by peening over the end of a reduced neck or extension 33 which projects loosely through a rectangular aperture 25 in the end plate 24 of the stationary member 20. The neck is of slightly less height (as viewed in Fig. 1) than the height of the aperture 25 but the aperture 25 is long enough to act as a guideway permitting limited movement of the clamp member bodily as the screw 40 and clamp are moved toward and from the side plate 22.

The clamp member is thus permanently attached loosely to the stationary member 20 in a way that permits hinged movement about its point of attachment 33, or bodily to a limited extent toward and from the side plate 22. In practice the maintenance of the clamp in proper position and the guiding of its movement at times when the screw is removed enables the screw to be reinserted and threaded into the tapped hole in the clamp practically always on the first try. Moreover the attachment of the clamp to the terminal member 20 enables both of those terminal members to be inserted as a unit "into the base, thus economizing materially on manufacturing, assembly labor and cost.

- As shown in Fig. 5, the end of the clamp member forming the hinge and support need not in all cases be peened over. The hinged end may be made with a neck 31 connecting the body 30' with a head 33'. The transverse 7 clamp back to lie vertically (as in Fig. l) the head will hold the clamp from falling away from the terminal 20,

but still in hinged condition and attached permanently to the terminal to the extent that the clamp cannot-accidentally fall away or get lost from the terminal.

As shown in the invention is applied to a switch contact terminal by bending down at a right angle'to the end plate an arm or extension 26 therefrom. a A contact button 28 is mounted on the end of the arm for engagement by a movable switch contact (not shown). However, the invention is not limited to switches but can be applied to attachment plug receptacles and electrical devices-of all sorts.-

Modifications within the scope of my invention will occur to those skilled in the art. 6

"What is claimed is:

1. A' wire terminal for electrical devices comprising a 4.-

stationary member having a side plate portion and an end plate portion bent at substantially a right angle thereto, one of said portions having an aperture therein, a

, clamping member having a tapped hole, a screw having its shank passing freely through said aperture and threaded into said tapped hole for causing said clamping member to move toward and from said apertured portion, said clamping member having a portion adjacent one end extending into an orifice in the other portion of said stationary member, said portion adjacent said end being made larger than the corresponding dimension of said 4 clamping member and said stationary member, said lug limiting the insertion of said bared end to a predetermined length. I

2. A wire terminal and insulating housing combination as claimed in claim 1 wherein said enlarged end portion is formed by peening over, thereby inseparably engaging said clamping member and stationary member.

3. A wire terminal for electrical devices comprising a stationary member having aside plate portion and an end plate portion bent at substantially a right anglefthereto, one or" said portions having an aperture therein, a clamping member having a tapped hole, a screw having its shank passing freely through said aperture and threaded into said tapped hole for causing said clamping member to move toward and from said apertured portion, said clamping member having a portion adjacent one end extending into an orifice in the other-portion of said stationary member, said portion adjacent said end being made larger than the corresponding dimension'of said orifice to maintain said clamping member hingedly mounted on said stationary member with said aperture and tapped hole in register, the end of said clamping member opposite the hinge being free, and an insulating housing enclosing said terminal and having an opening in one wall through which said screw is insertable into said terminal, means for mounting said stationary terminal member in said housing across said opening with said clamping member in back thereof, said terminal being mounted in position to have the bottom edgeiof said clamping member guided in movement by a portion of the housing, and a bent lug on said stationary member adapted to guide the top edge of the clamping memher.

4. A Wire terminal and insulating housing combination as claimedin claim 3 in which said lug is positioned over an opening in said housing through which the bared end of a conductor wire may be inserted between said clamping member and said stationary member, said lug limiting the insertion of said bared end to a predeterorifice to maintain said clamping member hingedly mounted on said stationary member with said aperture and tapped hole in register, the end of said clamping member opposite the hinge being free .and an insulating .t

from the top edge of said apertured portion positioned over an opening in said housing through which the bared end of a conductor wire may be inserted between said mined length.

5. A wire terminal and insulating housing. as claimed in claim 3 wherein said enlarged end portion is formed by peening over, thereby ,inseparably engaging said clamping member and stationary member. I 6. A wire terminal as claimed in claim 1 wherein said enlarged end portion comprises a head the distance across which is less than the greatest dimension of said orifice but greater than the dimension of said orifice in alignment with the plane of said clamping member when the latter is in operative position. 6

7. A wire terminal as claimed in claim 3 wherein said enlarged end portion comprises a head the distance across which is less than the greatest dimension of said orifice but greater than the dimension of said orifice in alignment with the plane of said clamping member when'the latter is in operative position.

References Cited in the file of this patent UNITED STATES PATENTS Germany Sept. 4, 1923

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