Title:
INSULATED COMMON STRIP
United States Patent 3760330


Abstract:
An insulated common strip for selectively coupling electrical components to the circuits of a printed wiring card. A self-tapping screw is used to close an electrical path between first and second pretensioned spring conductors mounted on an insulating block and coupled to the printed circuits.



Inventors:
Bennett, Joseph C. (Lisle, IL)
Wenzel, Anton (Villa Park, IL)
Application Number:
05/239983
Publication Date:
09/18/1973
Filing Date:
03/31/1972
Assignee:
GTE AUTOMATIC ELECTRIC LABOR INC,US
Primary Class:
Other Classes:
439/781
International Classes:
H01R9/00; H01R29/00; (IPC1-7): H01R9/00; H01R29/00
Field of Search:
339/17,18,19,176,198,246,249,265
View Patent Images:
US Patent References:
3656091TERMINAL JUNCTION SYSTEM1972-04-11Anhalt et al.
3238496Electrical connectors1966-03-01Crowther
3215968Printed circuit board connector1965-11-02Herrmann
3035242Meter socket by-pass1962-05-15Sloop
2133676Game apparatus1938-10-18Walaity
1092037N/A1914-03-31Gambrell



Foreign References:
CH242434A
GB393544A
DE1490440A1
Other References:

"Becon" Connector, Brown Engineering Company Becon 90.degree., Single 10 12-1961..
Primary Examiner:
Champion, Marvin A.
Assistant Examiner:
Lewis, Terrell P.
Claims:
Having described what is new and novel and desired to secure by Letters Patent, what is claimed is

1. Apparatus for selectively coupling electrical circuits comprising

2. Apparatus as recited in claim 1 further including

3. Apparatus as recited in claim 1 further including

4. Apparatus as recited in claim 1 wherein said mounting block is provided with a plurality of apertures having openings on each surface of said mounting block between the spring members of each said pair.

5. Apparatus as recited in claim 2 wherein

6. Apparatus as recited in claim 5 wherein

7. Apparatus as recited in claim 1 further including

8. Apparatus as recited in claim 7 further including

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of apparatus for interconnecting electrical circuit paths and more particularly to a new and improved insulated common strip.

2. Description of the Prior Art

Prior to the present invention the use of strapping blocks for selectively coupling circuits together were known. These strapping blocks basically involve the use of wire bars mounted on an insulating panel; one bar coupled to a first portion of a circuit and another parallel bar coupled to a second portion. The circuit portions were then coupled together through the head of a conductive screw threaded in a socket disposed between the wire bars. Although such strapping blocks have generally been considered adequate for use in electronic assemblies formed of discrete wired components they have exhibited deficiencies when used with modern printed circuitry. These prior art devices function satisfactorily to selectively couple circuit components, however, due to their panel-like structure could not be conveniently mounted directly on printed wiring cards. This, of course, presented a requirement that the strapping blocks be separately mounted and wired to the printed wiring card sockets of a wiring card file.

OBJECTS AND SUMMARY OF THE INVENTION

From the preceding description it will be understood that among the various objectives of the present invention are included the following:

THE PROVISION OF A NEW AND IMPROVED STRAPPING BLOCK;

THE PROVISION OF APPARATUS OF THE ABOVE-DESCRIBED CHARACTER WHICH IS EASILY MOUNTED DIRECTLY TO A PRINTED WIRING CARD; AND

THE PROVISION OF APPARATUS OF THE ABOVE-DESCRIBED CHARACTER HAVING PRE-TENSIONED SPRING CONTACTS.

These and other objectives of the present invention are efficiently achieved by providing an insulative block with a pair of pre-tensioned conductive circumferential springs, one end of each extending beyond the surface of the block. The spring ends are adapted for insertion through apertures in printed wiring cards such that they may be soldered to circuits printed thereon. A self-tapping electrically conductive screw is inserted into the block between the springs such that electrical contact is provided when the screw head is tightened against the springs.

The foregoing as well as other objects, features and advantages of the present invention will become more readily understood from the following detailed description taken in conjunction with the appended drawing.

BRIEF DESCRIPTION OF THE DRAWING

The single appended FIGURE is a perspective view of an insulated common strip constructed in accordance with the principles of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the FIGURE there is shown an insulative block 10 of generally rectangular configuration and having a plurality of spring receiving slots 12 disposed in the major surfaces. The block may conveniently be molded of an insulating plastic material, such as one of the many polycarbonate resins which are commercially available, and may include orthogonal through-holes 14 and spacing tabs 16.

A plurality of pre-tensioned wire springs 18, one pair for each electrical connection to be provided, are placed in the slots 12 with one end of each spring extending beyond the surface of the block 10. The springs are formed of tin plated spring temper rectangular wire and pre-tensioning is conveniently provided by the geometry of the spring itself; i.e., the curvature of the four sides of the springs 18.

To effect an electrical connection between the springs 18 of a given pair of an electrically conductive self-tapping screw 20 is driven into any one of the through holes 14 such that the screw head engage sobht of the springs 18 of the pair. Due to the pre-tensioning of the springs a reliable contact is made as the screw 20 is tightened. To open a given contact the screw 20 need only be turned out until the circuit is interrupted.

The common strip may conveniently be coupled to a conventional printed wiring card shown in part at 22. The ends of the springs 18 which extend beyond the surface of insulative block 10 are inserted in the plated through holes of circuit terminations 24 and soldered thereto. The spacing tabs 16 assure that the springs 18 on the side of block 10 adjacent the wiring card are not compressed against the card. The wiring card 22 may further, if desired, be provided with a plurality of apertures 26 in register with the through holes in the insulative block. In this fashion a self-tapping screw 20 may be inserted into the block 10 from any of its sides.

It will thus be seen that the applicants have provided a new and novel insulated common strip whereby the objectives set forth hereinabove are efficiently achieved. Since certain changes in the above-described construction will occur to those skilled in the art without departing from the scope of the invention it is intended that all matter contained in the foregoing description or shown in the appended drawing shall be interpreted as illustrative and not in a limiting sense.