US 3588786 A
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United States Patent lnventor Joseph A. Alfiero 802 15th St, W. Babylon, N.Y. 11704 App]. No. Filed Patented Nov. 10, 1969 June 28, 1971 CONNECTOR FOR TERMINAL STRIPS 3,489,986 1/1970 Frederick ABSTRACT: A connector for making contact to an electrical terminal strip having spaced apart pins arranged in rows. A preferred embodiment of the connector comprises two rectangular plates of insulator material with channel-shaped contactors of conductive material spaced apart along one edge of each plate to correspond to the spacing of the pins of the strip. A U-shaped bracket each of whose flanges has one of the plates mounted thereon maintains the plates with the contactors facing outwards. A wedge mounted between the confronting surfaces of the plates is used to selectively spread the plates apart in order to push the contactors against the pins and ensure reliable contact.
I 1 1 I 1 I, 1 l7 25) '7 34 I Q I Patented June 28, 1971 2 Sheets-Sheet 2 HG. 4A.
INVENTOR FIG. 4B.
CONNECTOR FOR TERMINAL STRIPS BACKGROUND OF THE INVENTION This invention relates generally to novel connecting means for making contact to electrical terminal strips having rows of pins or lugs. More specifically, the invention discloses means for concurrently contacting the pins of a terminal strip, even though the strip was not initially designed to have a mating part.
One example of a terminal strip in question is the heavy duty type used, for example, by telephone companies to terminate conductors originating at a given point (e.g., switch board) and to couple thereto various output lines (e.g., telephone extensions). Another example of a terminal strip, though more delicate, is the "platter or back plane of logic card assemblies containing large arrays of pins used by computer manufacturers to interconnect large numbers of integrated circuits. The terminal strips in question thus function as terminal boards. That is, each lug or pin on the strip may serve both as the termination of a signal or power line and as the distribution point for that signal or power line.
At present, when any work has to be done on these strips, such as, for example, connecting or disconnecting a wire to or from the strip, only one pin can be worked on at a time and, during the time the strip is being worked on any power or signal applied to the strip must be removed to prevent possible short circuits. This causes considerable down" time and an interruption in service to the other users of the strip. This problem is made more acute when it becomes necessary or desirable to do work on some or all of the pins on the terminal strip. Thus, for example, if most or all of the wires on one strip were to be removed and connected to another strip, the down" time to perform the transferral would be considerable and in addition many errors due to wrong wires being removed, replaced, or mislabeled would be introduced.
It is therefore important to have connecting means which will be capable of reliably mating to all of the pins of a terminal strip. However, designing a connector to mate with all of the pins of these terminal strips is complicated by the fact that their lugs or pins are often of odd shapes, are often not straight and are usually corroded or oxidized which makes difficult a good, low impedance electrical contact. Also, since the strips are not designed to have mating parts, the tolerances are loose on the dimensions of the pins and the distances from pin to pin.
It is therefore an object of this invention to provide means for reliably contacting concurrently a multiplicity of pins and lugs ofa terminal strip.
SUMMARY OF THE INVENTION A connector for making contact to spaced apart pins arranged in rows. The connector includes plates of insulator material with contactors of conductive material spaced apart along one surface of each plate. Mounting means are provided to hold the plates with the contactors facing outward and also provided are means for spreading the plates apart.
BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings like reference characters denote like components; and,
FIG. I is a cross-sectional end view of a connector embodying the invention mounted on a typical terminal strip;
FIG. 2 is a front view showing the mounting of contacting elements on one of the plates of the connector;
FIG. 3 is a detailed perspective view of a contactor used in conjunction with the connector of the invention;
FIG. 4A is a cross-sectional end view of a modified form of a connector embodying the invention; and
FIG. 4B is a bottom view of the connector of FIG. 4A taken along line 4-4.
DETAILED DESCRIPTION FIG. 1 shows a cross-sectional end view section of the connector mounted on a terminal strip, 10. The terminal strip 10 with pins or lugs 11 is of the type discussed above and illustrates the problems listed there. Thus, alternate pins (lugs) along the strip are not orthogonal with respect to the horizontal presenting a problem of mounting the connector. The pins are irregularly shaped, being hooked at the top and flaring outwards towards the strip base, presenting a problem of how and where to make contact to these pins. Also, some of these strips with which the connector is adapted to be used may be very old and these pins may be twisted and bent. Furthermore, the pins may be overlayed with an oxide layer (an insulator) making good electrical contact difficult. These and other problems are overcome by connectors embodying the invention.
The connector of FIG. 1 comprises two similar plates I2 and 14 which are connected to the flanges 17 of U-shaped bracket 16. The plates are of insulator material, such as linen bakelite, which in addition to being nonconductive is suitable to being worked (e.g., drilled and/or riveted) without breaking. The dimensions of the plates are dependent on the terminal strip to which the connector is to mate. Thus, the height of the plates is greater than the height of the pins on the strip and the length of the plates is selected to correspond to the length of the strip. The thickness of the plates is selected to ensure their rigidity when the connector is mated to the terminal strip and is under pressure.
Each plate is connected to one of the flanges. The bottom outer edge 34 of each plate is undercut as at 35 so as to permit the contactors 40 to be deflected as they contact the pins 11 when the plates 12 and 14 are spread apart as hereinafter described. The contactors 40 are the elements which contact the pins and are sown mounted on the lower portion of the plates. The flanges 41, 43 of the contactors project outwards from the outer surfaces of the plates with the lower flanges 43 contacting the pins and upper flanges 41 each having a wire 46 attached thereto.
U-shaped bracket 16 is channel shaped and comprises a horizontal web having depending flanges 17 which are bent inwards. The materials used to make the bracket should be resilient so that the depending flanges 17 may be deflected as hereinafter described. The width of the web is selected to approximate the distance between the two rows of pins while its length is substantially equal to the length of the plates. The tapering effect of the inwardly bent flanges is such that when the plates are mounted thereon they are inclined toward each other at an angle such that the lower edges 34 are very close together. This facilitates the insertion of the connector between the rows of pins on the terminal strip and as described below permits mating the connector with the strip while the latter is fully wired and powered with little fear of short circuits.
The plates 12 and 14 may be secured to the flanges 17 in any suitable manner. In FIG. 1, the plates are shown attached to the flanges by means of screws 18 and 20. However, the plates may be secured to the flanges by rivets or be bonded thereon by epoxy. Alternatively, the bracket 16, flanges l7, and the plates l2, 14 could be formed integrally from a single piece of material.
Means are provided for spreading the places 12 and 14 apart so that their contactors 40 are forced into contact with the pins or lugs 11. In the embodiment illustrated, this is accomplished by the provision of a wedge 32 which is operable from above the bracket 16 as hereinafter described.
A threaded nut 24 is mounted on top of the web of bracket 16, and is secured thereto in any suitable manner as by soldering or pinning. The nut is centered above a hole 25 in the web midway between the flanges 17. A screw threaded shaft 26 extends between the confronting surfaces of the plates 12, 14 through the nut and web. At one end thereof is a knurled knob 28 used to rotate the shaft. The other end of the shaft 26 extends through a hole 31 in a wedge 32 and tenninates in a head 30 which supports wedge 32. The shaft 26 also extends through a threaded nut 34 which is secured to the shaft 26 in any suitable manner. As will be understood, rotation of the shaft 26 will raise or lower the wedge. A plurality of shaft and nut assemblies as shown in FIG. 2 may be mounted along the length of the connector.
As shown in FIG. 1, the wedge 32 has been forced downwardly to spread the plates apart to force the contactors into contact with the pins. When it is desired to place the connector in position on a terminal strip, the wedge may be retracted by rotating shaft 26 to raise the wedge to a position contiguous to the web of bracket 16 where it has no effect on the separation of the plates. Thereafter, the wedge may be forced downwardly in order to spread the plates apart by rotating shaft 26 in the opposite direction. The wedge drives both plates equally and with great force, if necessary, so that a high contact pressure can be achieved without distorting the alignment of the plates.
A side view of the connector showing one of the plates l2, 14 with a row of contacts 40 mounted thereon is shown in FIG. 2. The contactors are spaced apart along the plate and since they are not in contact and the plate is of insulator material, the contactors are electrically as well as physically isolated from each other. The contactors are secured to the plates in any suitable manner, as by means of rivets 42, 44 for strength, simplicity and reliability. However, the contactors could also be screwed'or epoxied to the plate which could be a printed circuit board. It it also shown, as mentioned above, that more than one shaft 26 may be needed to support and move the wedge bar.
A detailed sketch of a contactor is sown in FIG. 3. The contactor 40 is preferably a U-shaped or channel-shaped element having two projecting, relatively parallel, members or flanges 41,43 separated by web 45. The web 45 is rectangular and flat and may have one or more centrally located holes 48, 49 which are used to couple the contactor to the plate. The bottom flange 43 of the contactor is notched. When the notch contacts the pins, the shape of the notch provides a small contact area to the pins, but, there is great pressure at the point of contact resulting in a reliable electrical connection because any insulator layer on the pins, if present, is penetrated. The point of contact referred to above includes the line and area contact between the pins and the notch. The notch also serves to capture and hold the pins to make reliable contact with pins which may have been out of alignment. The edge of the flange 43 could also be curved with the curve being concave or convex, straight, or slanted to either side. Thus, though the flange in the embodiment ment shown in FIG. 3 is notched and the notch shown forms an angle of less than 180 (straight angle), any projection capable of contacting the pins of the terminal strip to be mated is suitable. The contactor should be of conductive material and should be flexible to withstand the stresses and pressures it has to bear. Contactors made of annealed beryllium and copper (Be-Cu) which were spring tempered provided good results in an experimental unit.
The upper flange of the contactor has an eyelet 47 to which one or more conductor wires may be connected. The maximum width of the contactor is determined by the spacing of the pins with the contactors being narrower than the minimum distance between two pins to ensure that two pins cannot be short circuited by an one contactor.
A prototype unit substantially as described in FIGS. 1, 2 and 3 designed to mate with a 1828 and C terminal strip manufactured by Western Electric was built. Each of two plates, l.5 inches in width by l6 inches long, had 50 contactors mounted at regular intervals thereon. Each contactor was approximately I.l inches long and 0.2 inches wide. The bottom flange 43 of each contactor had a notch whose apex was at the nominal center of the flange and whose sidcn were mutually perpendicular. The prototype unit was mated to the above cited terminal strip and the combination tested. All the contactors made good contact to their corresponding pins and the gripping action provided by the contactors maintained the connector secured to the terminal strip.
In FIG. 4A and 48 a modified form of connector embodying the invention is shown in which the wedge is moved upward to cause an outward deflection of the lower edge of the plates.
FIG. 4A shows a cross-sectional end view with the connector making contact to a lug 11 of a terminal strip. Two insulated blocks 50, 52 (thick plates), having flat side surfaces on which are mounted contactors 40 of the type discussed above, replace the relatively thin plates 12, 14 of FIG. 1. The interior surfaces of the blocks 50 and 52 are beveled flaring out towards the base. A screw threaded shaft 26 is held between the two blocks by means of bushing 56 to which are coupled flat springs 58 which are attached to the contactor block and act as hinges when the contactor blocks are spread apart. The wedge 54 is mounted at the bottom of shaft 26. When knob 28 is rotated, the wedge is raised or lowered causing the contactors 40 to push against the pins or to be retracted therefrom.
FIG. 4B shows a bottom view of the connector taken along line 4-4. The pins are shown making contact in the center of the contactors, but it should be evident from the drawing that the notched flanges allow for a wide variation in the spacing of the pins and still provide a high pressure, low impedance electrical connection.
The connector embodying the invention is thus designed to be easily inserted between the rows of a terminal strip when the wedge is retracted to move the rows of contactors toward each other. Once the connector is inserted between the rows, natural spring action of the U-bracket holds the connector in place. Knob(s) 28 may then be turned to spread the plates apart and to press the contactors against the pins. Also, the contactors, especially when notched, ensure that whether or not the pins are aligned there is a high pressure contact point and that a reliable electrical connection is made.
The connector as designed may also be inserted onto a terminal strip which is fully powered with little fear of short circuits. After electrical connection is made, all the wires on a terminal strip may be transferred to the connector with little or no interruption in service and the connector could then by removed from one terminal strip and made to mate with another terminal strip with little or no interruption in service and with little chance of error.
Another feature of the connector is that the contactors provide easy access to the pins. This permits the connector to be prewired and connected to the terminal strip and the contactors on the connector may then be used to either apply signals to the pins of the strip or else to sense signals emanating from the terminal strip.
The above-mentioned features are set forth as an indication of some of the advantages of the invention and are not designed to limit its scope. It will be appreciated from the illustrated and described embodiments that the disclosed invention provides means to contact positively and reliably a multiplicity of pins and lugs on a terminal strip even though the strip was not originally designed to have a mating part.
Modifications of the disclosed embodiments, such as an increase in the number of plates may be made without departing from the invention as claimed.
1. A connector for making contact to spaced apart pins arranged in rows, comprising:
two plates of insulator material;
a plurality of contactors of electrically conductive material adapted to make contact to said pins mounted in a row on each of said plates with the contactors of each row spaced at regular intervals corresponding to the spacing of said pms;
means for supporting said plates with said plates facing each other; and
means for spreading said plates apart to cause said rows of contactors to contact the corresponding pins.
2. The combination as claimed in claim 1, wherein each of said contactors comprises a first section which is secured to one of said plates and a second section which includes a flange projecting away from said plates and adapted to make contact to said pins.
3. The combination as claimed in claim 2, wherein the flange included in said second section is notched.
4. The combination as claimed in claim 2, wherein said contactors are U-shaped elements having a flange at each end of a web, wherein the web is said first section, wherein one of said two flanges is said second section, and wherein the other one of said two flanges is adapted for the connection thereto of conducting means.
5. The combination as claimed in claim 4, wherein said supporting means comprises a U-shaped bracket having a horizontal web and two depending flanges at opposite sides of said web;
wherein one of said plates is mounted on one of said flanges;
wherein the other one of said plates is mounted on the other one of said flanges.
6. The combination as claimed in claim 5, wherein said means for spreading said plates comprises a wedge assembly including a wedge suspended between said plates and means to move said wedge relative to. said plates to push said plates apart.
7. The combination as claimed in claim 6, wherein said wedge assembly includes a threaded shaft rotatably mounted in the web of said U-shaped bracket and engaging said wedge so that rotation of said shaft advances or retracts said wedge to cause relative movement of said plates.
8. A connector, for making contact to spaced apart pins arranged in rows, comprising:
a number of plates of insulator material, each plate corresponding to a different one of said rows;
a plurality of contactors of electrically conductive material each contactor adapted to make contact to one of said pins;
means for attaching said contactors at spaced intervals corresponding to the spacing of said pins on one surface of each of said plates;
mounting means connected to each of said plates maintaining the surfaces of said plates facing each other; and
means for selectively spreading said plates apart to cause the contactors on the surface of each plate to contact the corresponding pins of a different one of said rows of pins.
9. The combination as claimed in claim 8, wherein the number of said plates is two, and wherein said contactors are flexible elements comprising a first section adapted to be mounted on said plates, a second section adapted to make contact to said pins and a third section adapted to have conducting means connected thereto.