US3873178A

US3873178A - Terminal clamp for electrical conductors

Info

Publication number: US3873178A
Application number: US392522A
Authority: US
Inventors: Anton Galli
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1972-09-04
Filing date: 1973-08-29
Publication date: 1975-03-25
Anticipated expiration: 1992-03-25
Also published as: FR2198283A1; IT995250B; CH561962A5; BR7306801D0; FR2198283B1; DE2243454C2; CA1000830A; ATA736973A; JPS4967186A; DE2243454B1; AR195754A1

Abstract

A terminal clamp for electrical conductors has a cylindrical clamping member which can be rotated in a clamping frame to clamp the conductor. The conductor is inserted into a conductor insertion opening disposed beyond the cylindrical surface of the clamping member. The opening extends in the longitudinal direction of the clamping member. The clamping surfaces of the cylindrical clamping member are eccentrically arranged in such a manner that they protrude beyond the cylinder surface of the clamping member and clamp a conductor inserted into the conductor opening against the clamping frame when the clamping member is rotated. The tool which is used to rotate the clamping member is then positioned in a direction parallel to the direction in which the conductor is inserted.

Description

United States Patent Galli Mar. 25, 1975 [75] Inventor: Anton GaIli,Schwandorf, Germany [73] Assignee: Siemens Aktiengesellschaft, Munich,

Germany [22] Filed: Aug. 29, 1973 [21] Appl. No.: 392,522

[30] Foreign Application Priority Data Sept. 4, 1972 Germany 2243454 [52] U.S. Cl. 339/274, 339/95 R, 24/134 R [51] Int. Cl. H01r 7/06, HOlr 9/08 [58] Field of Search 339/95, 96, 97 R, 98, 236, 339/238-240, 247, 273, 274; 24/134 R [56] References Cited UNITED STATES PATENTS 1,537,066 5/1925 Callender et al 339/95 B 2,125,203 7/1938 Schanbacher 339/239 2,314,219 3/1943 Johnson 339/239 2,698,424 12/1954 Allen 339/239 2,763,847 /1956 Hubbell 339/274 2,816,155 12/1957 Barnes 24/134 R X FOREIGN PATENTS OR APPLICATIONS 981,844 l/1951 France 24/134 R 534,051 12/1921 France ..339/273S Primary Examiner-Francis K. Zugel Assistant Examiner-Lawrence .l. Staab Attorney, Agent, or Firml(enyon & Kenyon Reilly Carr & Chapin [57] ABSTRACT A terminal clamp for electrical conductors has a cylindrical clamping member which can be rotated in a clamping frame to clamp the conductor. The conductor is inserted into a conductor insertion opening disposed beyond the cylnindrical surface of the clamping member. The opening extends in .the longitudinal direction of the clamping member. The clamping surfaces of the cylindrical clamping member are eccentrically arranged in such a manner that they protrude be yond the cylinder surface of the clamping member and clamp a conductor inserted into the conductor opening against the clamping frame when the clamping member is rotated. The tool which is used to rotate the clamping member is then positioned in a direction parellel to the direction in which the conductor is inserted.

12 Claims, 9 Drawing Figures PATENTEBHARZSHYS 3,873,178

: r g 13 H7 15 Fig-5 Fig.9

TERMINAL CLAMPFOR ELECTRICAL CONDUCTORS BACKGROUND OF THE INVENTION The invention relates to a terminal clamp for electrical conductors with a cylindrical clamping member which can be rotated in a clamping frame and has eccentrically arranged clamping surfaces. Deutsche Gebrauchsmuster 1,971,099 discloses a terminal clamp of this type wherein there is an essentially cylindrical clamping part which is rotatably supported in the bottom opening of a cup-shaped clamping frame and has a groove which is provided on the periphery of the cylindrical clamping part. The groove receives a conductor and extends in helix-fashion around the axis of rotation and at the same time becomes narrower. In this terminal clamp the direction of insertion of the conductor and the direction of applying a tool for turning the clamping part, for instance, a screw driver in the operating slot of the clamping part are therefore at right angles to each other. With the known terminal clamp it is furthermore only possible to clamp one conductor in the eccentric groove, for instance, a contact inserted into the cup, and the conductor must fit the dimensions of the groove. Furthermore, the cup is solid, so that a backward rotation of the eccentric cannot be pre vented reliably, particularly in the presence of vibrations or when temperature variations occur, because the conductor clamping part and the clamping frame consist of different material.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a terminal clamp of the above-mentioned type wherein the direction of operating the clamp and the direction of inserting the conductor to be clamped are parallel to each other so that the terminal itself requires relatively little space and still functions reliably.

Accordingto a feature of the invention, the eccentrically arranged clamping surfaces protrude beyond the cylinder. Further, the clamping frame has at least one conductor insertion opening disposed outside the cylinder in the longitudinal direction of the cylinder.

Terminal clamp of the invention includes a cylindrical clamping member having a cylindrical surface and defining a longitudinal axis. A clamping frame accommodates the clamping member and defines at least one insertion opening for receiving an electrical conductor therein. The opening extends in the direction of the above-mentioned longitudinal axis and is located be yond the cylindrical surface of the clamping member. The clamping member is rotatably mounted in the clamping frame for clamping the conductor and has a portion which protrudes eccentrically from the cylindrical surface to define at least one clamping surface.

Particularly for clamping several conductors to each other or to a contact piece inserted into the clamping frame, it is advantageous if the clamping frame is resilient. The manufacture of the terminal clamp according to the invention, and especially the assembly of the clamping cylinder in the clamping frame, is facilitated considerably if the clamping frame is made up of a U- shaped guide part for accommodating the clamping member and a pressure plate which closes the U and is fastened to the guide part. If the guide part and the pressure plate are hooked into each other additional assembly steps are unnecessary. The required space and material can be reduced furtherif. for instance. the guide member and the pressure plate are joined together by peening.

It is advantageous that the pressure plate is notjoincd to the clamping frame rigidly, more specifically, the clamping frameitself can twist because then the pressure plate can adapt itself to the pitch of the eccentric portion of the clamping member when two conductors are connected.

The bearing of the clamping member is improved when the clamping frame is configured to have bent-in portions between where the clamping member is mounted and where the conductor is accommodated. These bent-in portions are particularly advantageous for the resiliency of the clamping frame and for matchingto the pitch of the eccentric portion if at least parts of the clamping frame are made of spring steel. Additional security against the conductor being pulled out is provided by a terminal clamp configuration in which the eccentrically arranged clamping surfaces around the cylindersurface are disposed at an angle to the longitudinal axis of the latter.

Symmetrical pressure conditions can beobtained in such a configuration when two clamping surfaces are arranged about the cylinder surface and when their respective planes intersect to define an obtuse angle. Defined contact surfaces for a conductor to be clamped and a shortening of the lift of the eccentric portion in the case of two conductors of smaller cross-section can be obtained if the pressure plate is curved away from the clamping member.

Although the invention is illustrated and described herein as terminal clamp for electrical conductors, it is nevertheless not intended to be limited to the details shown, since various modifications may be made therein within the scope and the range of the claims. Theinvention, however, together with additional objects and advantages will be best understood from the following description and in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of the terminal clamp according to the invention. The clamp is shown in its open position.

FIG. 2 shows the terminal clamp with one conductor inserted therein.

FIG. 3 shows the terminal clamp with two conductors inserted therein, the conductors having a cross-section less than the conductor shown in FIG. 2.

FIGS. 4 and 5 show respectively a plan view and an end view of the U-shaped guidance part of the clamping frame.

FIGS. 6 and 7 show respectively a front view and an elevation view of the pressure plate which is connected to the guidance part.

FIGS. Sand 9 show respectively a front view and an elevation view of the clamping member and the portion thereof defining the eccentric clampingsurfaces.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Referring to FIG. 1, the clamping frame 1 of the terminal clamp according to the invention includes the guide part 2 for the cylindrical clampingmember 3 having an eccentrically disposed clamping surface 4. The frame 1 further includes a pressure plate 5 which is hooked into the arms 6 of the guide part 2. For this purpose an opening 7 is provided in the arm 6 as shown in FIG. 5, into which projections 8 of the pressure plate are hung. The pressure plate 5 is, for instance, slightly curved at its center portion, as shown in FIGS. 6 and 7.

A contact element 9, preferably aconducting bar, which can be brought into conducting contact with

conductors

10 or 11, is inserted into the pressure plate 5 in the embodiment of FIGS. 1 to 3. The clamping sur faces 4 are provided at an eccentric portion 12 formed on the cylindrical clamping member 3 which protrudes through a cutout 13 shown in FIG. 5. The webs 14 between the opening 7 and the cutout l3 serve as stops for the eccentric portion 12 in the fully opened condi tion shown in FIG. 1. The pitch of the eccentric portion 12 and therefore, the position of the clamping surfaces with respect to the pressure plate 5 is chosen so that self-locking takes place. However, it is advantageous, provided the U-shaped guide part is resilient and, for instance, consists of spring steel, to provide bent-in portions 15 at the arms 6 which yield if the terminal is tightened; this action connects the conductors 10 and /or 11 reliably with the contact element 9 also in the presence of temperature variations and vibration.

As shown in FIGS. 8 and 9, the clamping surfaces 4 can be disposed at an angle to the cylindrical surface of the clamping member 3. In the illustrated embodiment, these are two ring surfaces about the cylindrical surface which conjointly define an obtuse angle so that the conductor is readily deformed when clamped; this makes it harder to pull the conductor out of the terminal clamp in the clamped condition. Serrations can be applied to these surfaces.

Referring to FIGS. 1 to 3, the terminal clamp according to the invention is utilized, for instance, by inserting the conductors 10 into the open terminal clamp and the clamping member 3 is turned to the right to the position shown in FIG. 3 or, if one conductor is inserted to the position shown in FIG. 2, for example, by inserting a screw driver into the slot 16 and turning the same; this causes the bent-in portions 15 to recede slightly which in turn leads to an elastic tightening of the

conductors

10 or 11 against the fixed contact 9. The terminal clamp is opened by turning the clamping member 3 to the left.

The terminal according to the invention requires very little space and is particularly well suited for connecting to the rear contacts of the push buttons.

What is claimed is:

' l. A terminal clamp for electrical conductors, comprising a cylinder-like clamping member having a cylindrical surface and defining a longitudinal axis;

a clamping frame including a U-shaped bent guide part for accommodating said clamping member and defining at least one insertion opening for receiving an electrical conductor therein, said opening extending in the direction of said axis and being beyond said cylindrical surface. said clamping frame being configured so as to have bent-in portions between where said clamping member is disposed and said insertion opening;

said clamping member being rotatably mounted in said clamping frame between said bent-in portions and the bight of said U-shaped guide part for clamping the electrical conductor, said clamping member having an eccentric portion protruding eccentrically from the cylindrical surface thereof to define at least one clamping surface, and

a pressure plate attached to said guide part so as to close the open end of said U-shaped guide part.

2. The terminal clamp of claim 1, said clamping frame being made of resilient material.

3. The terminal clamp of claim 1, said clamping frame being configured so as to be bendable into itself.

4. The terminal clamp of claim 1, said guide part and said pressure plate being hooked into each other.

5. The terminal clamp of claim 4, said guide part and said pressure plate being peened to each other.

6. The terminal clamp of claim 1, said pressure plate being arched away from said clamping member.

7. The terminal clamp of claim 1, said clamping frame and said pressure plate being serrated.

8. The terminal clamp of claim 1, said guide part being serrated.

9. The terminal clamp of claim I, said pressure plate being serrated.

10. The terminal clamp of claim 1 wherein at least one of said clamping frame and said pressure plate is made of spring steel.

11. The terminal clamp of claim 1, said eccentric portion of said clamping member defining clamping surfaces which extend about said cylindrical surface at an angle to said longitudinal axis.

12. The terminal clamp of claim 11, said clamping surfaces defining an obtuse angle and being disposed on said eccentric portion so as to extend about said cylindrical surface.

I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,873,178

DATED l March 25, 1.975

INVENTOR(S) I ton Galli it is certified that errer appears m the ahrive identified patent and that said Letters Patent are hereby corrected as shown below In the Abstract, line 5, change "cylnindrical" to read -cylindrical- In the Abstract, line 15, change "parellel" to read parallel- In Column 3, line 29, change "cylindrical surface" to read --cylinder surface-- Signed and Scaled this Arrest:

RUTH C. MASON Aucsrr'ng Officer C. MARSHALL DANN Commissioner of Parents and Trademarks

Claims

1. A terminal clamp for electrical conductors, comprising a cylinder-like clamping member having a cylindrical surface and defining a longitudinal axis; a clamping frame including a U-shaped bent guide part for accommodating said clamping member and defining at least one insertion opening for receiving an electrical conductor therein, said opening extending in the direction of said axis and being beyond said cylindrical surface, said clamping frame being configured so as to have bent-in portions between where said clamping member is disposed and said insertion opening; said clamping member being rotatably mounted in said clamping frame between said bent-in portions and the bight of said Ushaped guide part for clamping the electrical conductor, said clamping member having an eccentric portion protruding eccentrically from the cylindrical surface thereof to define at least one clamping surface, and a pressure plate attached to said guide part so as to close the open end of said U-shaped guide part.

8. The terminal clamp of claim 1, said guide part being serrated.

9. The terminal clamp of claim 1, said pressure plate being serrated.