US 3764957 A
Apparatus for enabling the rapid and reliable connection and disconnection of plug type connectors and their low cost manufacture, including a nut member that indicates when a screw is fully tightened, frames that facilitate unplugging in a commonly practiced though officially unrecognized manner, and contact elements shaped for accurate location in the frames. The nut member has a thread-engaging lip initially angled to extend away from the other connector frame, so that as a screw from the other frame becomes fully tightened the lip deforms and thereby suddenly increases screw-tightening resistance that signals the repairman to stop turning the screw. The female frame of a connector set has end walls that are tapered to permit disconnection of the frames by tilting them away from one another without binding. The recesses in each frame that receive tiny contact elements, have inwardly extending flanges near the tops of the recesses, and each resilient contact element has a wide lower portion biased upwardly against the flanges and a narrower upper portion passing between and beyond the flanges.
Description (OCR text may contain errors)
United States Patent 1 Iversen [111 3,764,957 Oct. 9, 1973 ELECTRICAL CONNECTOR Ralph T. Iversen, Granada Hills, Calif.
 Filed: Dec. 17, 1971  Appl. No.: 209,323
 US. Cl. 339/92 R, 85/36, 339/184 M, 339/217 S  Int. Cl. HOlr 13/54, H0lr 13/64  Field of Search 339/92 M, 176 R, 339/176' M, 217 S, 184, 186; 85/36  References Cited UNITED STATES PATENTS I 3,617,985 11/1971 Kehl 339/92 M 2,383,211 8/1945 Plumb 85/36 2,567,884 9/1951 Heath 85/36 3,657,682 4/1972 lverson 339/103 M 2,775,917 l/l957 Ferguson 85/36 3,555,494 1/1971 Baumanis 339/217 S 3,601,751 8/1971 Pauza 339/217 S 3,633,152 l/1972 Podmore 339/217 S 2,938,190 5/1960 Krchbiel 339/176 M 2,669,702 2/1954 Klostermann 339/75 M 3,277,426 10/1966 Klostermann 339/176 R Primary Examiner-Marvin A. Champion Assistant Examiner-William F. Pate, lIl
Attorney-Samuel Lindenberg et al.
[5 7 ABSTRACT Apparatus for enabling the rapid and reliable connection and disconnection of plug type connectors and their low cost manufacture, including a nut member that indicates when a screw is fully tightened, frames that facilitate unplugging in a commonly practiced though officially unrecognized manner, and contact elements shaped for accurate location in the frames. The nut member has a thread-engaging lip initially angled to extend away from the other connector frame, so that as a screw from the other frame becomes fully tightened the lip deforms and thereby suddenly increases screw-tightening resistance that signals the repairman to stop turning the screw. The female frame of a connector set has end walls that are tapered to permit disconnection of the frames by tilting them away from one another without binding. The recesses in each frame that receive tiny contact elements, have inwardly extending flanges near the tops of the recesses, and each resilient contact element has a wide lower portion biased upwardly against the flanges and a narrower upper portion passing between and beyond the flanges.
7 Claims, ll-Drawing Figures I ll M ELECTRICAL CONNECTOR BACKGROUND OF THE INVENTION This invention relates to electrical connector apparatus One type of plug connector commonly usedintelephone installations and other applications includes a male frame or plug that can be inserted into a female frame or receptacle, so that contact elements of the two frames touch one another. Screw and nut type fasteners are often utilized to securely hold the frames together. One problem that often arises in field installations is over-tightening of the screws which damages the nut. This occurs largely because small screws are utilized which require only a small torque for tightening.
Another problem that often arises in field installations of connectors is binding during unplugging of the connectors. It is often assumed that the connectors will be unplugged by pulling one of them straight out from the other. However, in practice field repairmen often separate the connectors by tilting them apart, inasmuch as tilting provides greater leverage for initially loosening the connectors from one another. The ends of the connectors generally bind during such tilting, so that repairmen often have to tilt them back and forth while pulling them apart, which leads to increased effort and annoyance particularly in awkward installation areas.
' Each electrical connector of a set generally includes a row of recesses and a row of electrically conductive contact elements of spring material that lie in the recesses and have portions extending a slight distance therefrom. The contact elements must be bent to accurately follow .a predetermined curve so that when one side bears against the bottom of the recess the other side extends a small but definite distance out of the recess. However, it is difficult to bend such spring elements to close tolerances, so that close control of their shape involves substantial expense.
SUMMARY OF THE INVENTION In accordance with one embodiment of the present invention, an electrical connector assembly is provided which is easy to assemble and disassemble in the field and which can be manufactured at low cost. The assembly includes a plug and receptacle that can be connected and then securely joined by screws extending from one connector and engaged with a nut on the other connector. A sheet metal nut member is utilized which has a thread-engaging lip extending with a directional component away from the other connector. As the screw becomes fully tightened, the lip begins to be deformed, or coned over, and begins to extend with a directional component towards the other connector. The repairman can sense a sudden increase in resistance to screw turning as such coning over begins, so that he can cease further tightening. Even if further tightening occurs and the lip is fully coned over, it thereafter merely clicks on the threads when the screw is turned so the repairman can sense that no further tightening is required.
The connectors are constructed to allow disassembly of the plug from the receptacle by tilting them apart. To permit this, the ends of the receptacle walls are tapered so that they diverge, to provide clearance that allows tilting of the plug without binding on the receptacle. However, when the plug is fully installed, there is only a small clearance between its end walls and the nearest regions of the receptacle end walls, to assure accurate location of the plug.
Each of the connectors has a row of recesses that hold resilient contact elements, the elements being formed to extend a small distance out of the recesses so they contact corresponding elements on the other connector. In order to more accurately locate the protruding contact element portions, a pair of sidewardly extending flanges is formed in the recesses. Each of the contact elements is provided with a wide lower portion that lies in the recess below the flanges and that resil-' iently bears against the flanges, and is also provided with a narrow upper portion that extends between the flanges and a small distance out of the recess. The fact that the wide lower portion of the contact element is held at a predetermined depth within the recess means that the protruding portion of the element is more accurately located in depth, and therefore largerdimensional tolerances can be utilized in forming the contact element.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectional side elevation view of connector apparatus constructed in accordance with the invention, the connectors thereof being shown separated and ready for interconnection;
FIG. 2 is a perspective view of a nut member of the apparatus of FIG. 1;
FIG. 3 is an enlarged sectional side view of a portion of the apparatus of FIG. 1, showing a screw and nut member engaged;
FIG. 4 illustrates a portion of theapparatus of FIG. 3, but showing the configuration .of the nut member after overtightening of the screw;
FIG. 5 is a plan view of the connectorapparatus of FIG. 1, showing the faces of both connectors thereof;
FIG. 6 is a sectional side view of the connector apparatus of FIG. 1, showing the manner in which the two connectors can be tilted apart;
FIG. 6a shows the particular taper of the invention which allows tilting apart of the connectors;
FIG. 7 is a perspective view of a portion of a connector frame of the apparatus of FIG. 1;
FIG. 8 is a side view of the apparatus of FIG. 7;
FIG. 9 is a view of the apparatus of FIG. 8 in an assembled configuration; and
FIG. 10 is a view taken on the line 10-10 of FIG. 9.
DESCRIPTION-OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a pair of electrical connector assemblies 10, 12, each including a frame l4, l6 and a hood 18, 20. One of the frames 14, is a male frame of plug, while the other frame 16 is a female frame or r'ecepta cle that can receive plug 14. When the plug 14 is inserted into the receptacle 16, rows of contact elements 22, on the two frames engage one another to establish electrical contact between a group of wires 24 leading to the connector assembly 10 with another group of wires 26 leading to the other assembly 12.
After the two assemblies 10, 12 have been connected by inserting the plug into the receptacle, they are generally fastened together by the use of machine screws 28, that threadably engage nut members 30. It often requires many turns of the screw 28 before it becomes fully tightened on the nut 30. In prior art installations, field repairmen often could not determine when to stop tightening of the screws. Such over tightening could damage the typical sheet metal nut so that it would not hold the screw. In accordance with the present invention, the nut member 30 is formed so that it readily indicates to the repairman when full tightening has been achieved, and so that it functions to hold the screw even after over tightening.
As shown in FIG. 3, the nut member 30 that is installed on the connector assembly 12, has a pair of tread-engaging lip portions 32, 34 that extend with directional components away from the other connector assembly'l0. When the screw 28 is being tightened, the lip portions 32, 34 threadably engage the screw to advance it. As the screw 28 becomes fully tightened, so that its head 35 firmly engages a ledge 37 and cannot advance any further towards the nut member, it begins to pull out the lip portion 32, 34. If such turning of the screw 28 continues for a few turns, then the lip portions 32, 34 will be coned over, or in other words, bent in a reverse direction until they have the configuration shown at 32a, 34a in FIG. 4 wherein they extend with directional components towards the other connector assembly. However, as such coning over begins, the resistance to further turning of the screw 28 sharply rises. This signals the repairman that he has fully tightened the screw and should stop any further tightening. Accordingly, the repairman normally will not over tighten the screw so as to cone over the lips of the nut member.
The nut member can be formed from sheet metal, and has a sheet-like base portion 36 and two curved arms 38, 40 extending from the base portion. The base portion has a slot 42 of substantially constant width except at the center which forms the two lips 32, 34. The regions on opposite sides of the slot 42 are bent out of the plane of the rest of the sheet-like base portion, to allow the lip portions to extend at the required incline. Slits 44 are formed at opposite ends of the slot 42 to facilitate such bending of the regions on opposite sides of the slot. The two arms 38, 40 extend from opposite sides of the base, converging to locations aligned with the hole formed between the lip portions 32, 34 and then diverging. As shown in FIG. 3, the arms 38, 40 can engage the threaded shank portion of the screw to keep it oriented so that it threadably engages the lips 32, 34. The arms 38, 40 have free end portions 43, 45 that are received in slots 46, 48 of the frame 16 to retain the nut member 30 in a recess of the frame.
The nut member 30 is readily installed in the frame 16 by inserting it through an opening 50 therein until the free ends 43, 45 of the arms snap into the slots 46, 48. The base portion 36 of the nut member is held by an inner ledge formed by a wall 52 of the frame. The nut member 30 is useful during many tightenings and loosenings of the screw. If a repairman should accidently over tighten the screw and thereby cone over the lips to the positions of FIG. 4, the lips will still threadably engage the screw to prevent its free withdrawal. As the repairman continues to rotate the screw 28, the lips 32a, 34a will repeatedly rise and fall on the threads of the screw, creating clicking sounds that the repairman can sense. Thus, even if the nut is over tightened, it can still function, and can still inform the repairman when the screw is fully tightened so that he does not have to continue turning it.
It is often assumed that the plug 14 is removed from the receptacle 16 by pulling the plug straight out without tilting it. However, in practice the plugs are often tilted in the manner shown in FIG. 6 relative to the receptacle during removal. Repairmen often utilize this method because they can obtain greater leverage in loosening the plug from the receptacle by tilting it. However, the length of the plug-receiving region in the receptacle is often made only slightly greater than the length of the plug, in order to accurately locate the contact elements. As a result, repairmen using prior art connectors often had to tilt the plug or receptacle first one way then the other, since the connectors would bind on one another after a more than a few degrees of relative tilting.
In accordance with the present invention, the receptacle 16 is formed so that the length of the recess or receiving portion 60 gradually decreases with depth, from a minimum length only slightly greater than the length L of the plug at the innermost part of the region 60, and increasing to a substantially greater length. This is accomplished by tapering the end walls 62, 64 of the receptacle so that its inner surfaces diverge from one another at an angle A of more than several degrees. For a connector assembly where the length L of the plug is a plurality of times greater than the depth D, which is the typical situation, an angle A of divergence of the end walls of more than about 15 can allow complete disassembly by a single tilting without binding at the end walls. Of course the angle that is required depends upon the tolerances and the length-to-depth ratio of the plug. However, a draft greater than the draft of less than a few degrees, that is, less than about three degrees, that may be utilized in injection molding merely to permit ejection from the mold, is generally required.
When the connectors are separated in the manner shown in FIG. 6, the receptacle 16 can pivot about the point 66 while the opposite end wall 62 moves completely away from the plug 14, without binding. The fact that both ends of the receptacle are tapered means that pivoting can occur at the deepest position 66 rather than at a location such as a point 68 near the outer face of the receptacle. This means that the end wall 64 is not shifted outwardly so as to abut a shroud 70 that is typically provided to surround the plug 14. It would be possible to taper the ends of the plug 14 instead of the walls of the recess, but this could result in a requirement for greater tapering to prevent binding of the receptacle 16 with the shroud 70 on the plug.
FIGS. 7-10 illustrate the manner in which the contact elements 22 are received and held in one of the frames such as the plug frame 14. The frame 14 has numerous recesses arranged in two rows on either side of the frame, each recess holding one contact element 22. The contact elements 22 are formed with troughshaped rearward portions 82 for receiving and connecting to the bared ends of wires, and have loop-shaped forward portions 84 which are designed to contact similar elements of the other connector frame. The loopshaped forward portion may be considered as having an inner arm 86 that lies near the bottom wall 88 of a recess, and an outer arm'90 that protrudes past the walls of the recess.
The two arms 86, 90 of the contact element 22, amy be considered to be joined together at a forward location 92 where the loop has its sharpest curve. The contact element 22 is constructed of a conductive material which is highly resilient, so that the outer arm 90 can deflect inwardly as it encounters another contact element on the other frame, to firmly press against it. When the outer arm 90 is deflected inwardly, the element is bent primarily at the sharpest curved region 92. In prior art connector assemblies, relatively close tolerances had to be maintained over the form of the loop portion 84 and itsorientation with respect to the rearward portion 82 to assure that the inner arm 86 was initially bearing against the bottom wall 88 of the recess and so that the outer arm 90 extended a small but definite distance above the side face 94 of the frame. The accurate bending of such spring elements is difficult to achieve, and therefore considerable effort and expense was required in the forming of the contact elements.
In accordance with the present invention, the recesses 80 are formed with side walls 96 that have flanges 98 that extend towards one another to form a constriction near the outer end of the recess. Furthermore, the loop portion 84 of each contact element 22 is formed so that the inner arm 86 lies beneath the flanges 98 and is biased against them, while the outer arm 90 extends in a curve between and out past the flanges 98 and the side 94 of the frame. This is accomplished by forming the lower arm 86 with a width W (FIG. slightly smaller than the distance between the side walls 96 of the recess but greater than the width C of the constriction. The outer arm 90, however,'has a width which is less than the width C of the constriction, so that the arm 90 can pass between the flanges 98. The loop portion 84 of the contact element is formed so that the inner arm 86must be bent in order to fit between the bottom wall 88 of the recess and the flanges 98. This assures that the steps 100' formed at the intersection of the inner and outer arms bear against the bottom of the flanges 98. The outer arm 90 is formed with sufficient curvature so that part of it lies above the side face 94 of the frame. The fact that the steps 100 fix the location of the center of the loop portion, means'that the contact elements can be formed with smaller dimensional tolerances, and still there is assurance that the outer arm 90 will protrude a small but definite distance past the side face 94 of the frame.
The loop portion 84 of the contact element is constructed of a strip of resilient conductive material which is initially of uniform width. However, notches are formed at the steps or ledges 100, and portions 102 at the sides of the strip are bent over to reduce the width of the outer arm 90 so that it can passthrough the constriction betweenthe flanges of the recesses. Each contact element 22 can be installed in a recess 80 by moving the element forwardly through the recess beneath a retainer wall 104 that bridges the recesses. The element is moved forward until the front end of the element abuts the front wall 106 of the recess. In order to prevent retraction of the contact element, it is provided with a tab 108, as shown in FIG. 9, which normally lies above the bottom of the retainer wall 104. As the element is slid forward during installation, the tab 108 deflects downwardly under a ledge 110 on the retainer and the tab then springs up to lie in line with the ledge 110. The contact element 22 thereafter cannot be moved rearwardly out of the recess because the tab 108 will abut the ledge to prevent this.
Thus, the present invention provides connector apparatus that can be reliably installed, easily disconnected, and manufactured at low cost. Reliable fastening is facilitated by the use of a nut member with reversedeformable lips that initially extend away from the opposite connector but which can be bent to reverse their direction or inclination. The deformable lips provide a sudden increase in tightening torque that signals the repairman to stop tightening the screw, and even when the lips have been deformed because of over tightening, they provide clicks after full tightening that signal the repairman that the screw has been fully tightened. Disconnection of the connector assembly in a tilting manner is facilitated by angling at least one end wall of the connector, and preferably by angling both endwalls of the receptacle. This allows accurate location of the plug in the receptacle when it is fully installed, and yet allows disconnection by tilting one end of the plug away from the receptacle. Manufacture of the connectors is facilitated by utilizing flanges in the elementreceiving recesses of each connector frame,- and by utilizing contact elements with inner arms too wide to pass by the flanges and outer arms that pass between the flanges and a small distance past the sidewalls on the frame.
Although particular embodiments of the invention have been described and illustrated herein, it'is recognized that modifications and variations may readily occur to those skilled in the art and, consequently, it is intended that the claims be interpreted'to cover such modifications and equivalents. What is claimed is:
1. Electrical connector apparatus comprising:
a pair of connector assemblies, each having electrical contact elements that engage contact elements of the other when the two assemblies are connected, and each having screw-engaging means for enabling fastening by a screw to the other assembly;
at least one of said screw-engaging means which is on a first of said assemblies including a nut member having a thread-engaging lip portion extending with a directional component away from the other assembly and being deformable,-by rotation of said screw when it cannot advance any further into said nut member, to a reverse orientation extending with a directional component toward the other assembly;
said nut member including a sheet-like base portion with a slot therein and with slits extending perpendicular to said slot and intersecting opposite ends of said slot, said slot being widened at a center portion thereof so it can closely surround a cylindrical screw shank,
the portion of said base on at least one side of said slot being bent out of the plane of the rest of the sheet portions to extend with a directional component away from said second connector to form said thread-engaging lip portion;
said first connector assembly having a wall with a screw-passing hole therein and said base portion of the nut member resting against the wall but with the lip portion being unsupported by the edge of the hole, the hole being large enough so that a length of the lip portion at least twice the thickness of the lip portion extends into the hole to permit reverse lip deformation into the hole, whereby to permit permanent lip deformation so that a workman can notice a sudden decrease in resistance to tightening of the screw.
2. An electrical connector comprising:
a male frame having an elongated plug portion with a plurality of contact elements thereon; and
a female frame having an elongated receiving portion with a recess only slightly longer than said plug portion for closely receiving said plug portion, said female frame having a plurality of contact elements along said recess for contacting said elements of said plug portion when it is received in said recess;
said plug portion and said recess of said receiving portion being constructed so that at least one of them is tapered to have a progressively greater length at progressively greater distances from the portion that first engages the other frame when the frames are mated, said tapering being sufficient to allow one end of said plug portion to completely withdraw from said recess while the other end of said plug portion remains at substantially the deepest position to which it can be received in said recess.
3. The electrical connector described in claim 2 wherein:
said receiving portion has end walls whose inner surfaces each have a draft or more than 4. The electrical connector described in claim 2 wherein:
said plug portion is substantially a block with a length at least a plurality of times greater than its depth, and having a substantially constant length between its ends, and
said receiving portion has end walls defining said recess, that diverge from each other at an included angle of at least 15.
5. An electrical connector comprising:
a frame with a plurality of recesses that have opposite side walls and flanges extending from the side walls to leave a constriction of a predetermined width; and
plurality of resilient and electrically conductive contact elements, each element having a region formed into a loop, an inner portion of said region being wider than said constriction and lying deeper within said recess than said constriction, and said inner portion having an end where it merges with an end of an outer portion of said region which is narrower than said constriction, at least part of said outer portion lying within said constriction, said end of said inner portion being biased against said flange and said end of the outer portion lying in the constriction whereby to more accurately locate said outer portion in depth.
6. An electrical connector comprising: a frame with a plurality of recesses that have opposite side walls and flanges extending from the side walls towards each other to leave an opening of a predetermined width between them; and
a plurality of resilient, electrically conductive contact elements, each having first and second arms joined at one end to form a loop, said first arm being wider than said predetermined opening between said flanges and lying deeper within said recess than said flanges and biased against said flanges at a location beyond the beginning of the loop, and said second arm being narrower than said predetermined opening between said flanges and protruding from it, whereby said second arm is more accurately located in depth.
7. The electrical connector described in claim 6 wherein:
said first arm is resiliently deformed between a bottom wall of the recess and the flange, and the depth of the flanges is less than the depth of the recess between the bottom surfaces of the flanges and said bottom wall.