US 2636068 A
Description (OCR text may contain errors)
pril 21, 1953 R. L. PERKINS 2,636,068
MULTIPLE CONTACIT ELECTRICAL CONNEQTQR Filed Aug. 11, 1950 2 SHEETS-SHEET l IN V EN TOR.
Faber) L. erk/n5 1W fi em R. L. PERKINS MULTIPLE CONTACT ELECTRICAL CONNECTOR April 21, 1953 2 SHEETSSHEET 2 Filed Aug. 11, 1950 'I/II/IIIIII/I Patented Apr. 21, 1953 MULTIPLE CONTACT ELECTRICAL CONNECTOR Robert L. Perkins, St. Paul, Minn, assignor to Engineering Research Associates, Inc., Arlington, Va., a corporation of Minnesota Application August 11, 1950, Serial No. 178,772
This invention relates to multiple-contact electrical cable connectors and relates particularly to methods for insuring and maintaining positive contact of the electrical conducting elements of such multiple-contact electrical cable connectors. Additionally, this invention relates to a method for facilitating the insertion or separation of the cooperating parts by rendering substantially less the sliding friction of the mating parts during such insertion or separation, as compared to the friction during engagement.
Cable connectors provide a well-known method for connecting electrical conductors where a discontinuity exists in a cable. This discontinuity may be necessitated by a desire to break u long cables into lengths for convenient handling, by the requirements of joining lengths of cables at a particular location, or by the requirements of equipment portability or demountability. Standard cable connectors in present use rely on friction contact between the male and female conducting elements of the connector to complete the electrical circuit. The desire to maintain low contact resistance after repeated use of the cable connector is complicated additionally by the necessity of maintaining pin alignment of the male and female conducting elements before and during insertion and connection of the cable connector and the necessity of minimizing during insertion those stresses which would tend to deform and hence destroy the usefulness of the parts of the connector.
Accordingly, the principal object of this invention is to provide an improved means of making electrical contact between the male and female conducting elements of a multiple-contact connector, while selectively permitting ease of insertion of the conducting elements during coupling and ease of separation during decoupling.
One feature of this invention i the selective application of centripetal force on each of the female conducting elements of the connector, such application being effected after coupling by means of a simple hydrostatic-pressure converter which is actuated by an externally-supplied force.
An additional feature of this invention is that mechanical force may be selectively applied to an actuating member of the connector, where that force will be transformed to a centripetal pressure applied to each of the female receptacles individually.
Another feature of this invention is that pin alignment is insured and maintained firstly by rigid alignment spacers, and secondarily by limtipg thejpressure on the conducting elements which in the absence of such limitation might otherwise tend to deform them during coupling and decoupling of the connector.
Although the novel features which are believed to be characteristic of this invention will be pointed out with particularity in the appended claims, the manner of its organization and the mode of is operation will be beter understood by referring to the following description read in conjunction with the accompanying drawings, forming a part hereof, in which:
Figure 1 is an oblique view illustrating one type of a multiple-contact connector which shows the mating female and male elements of the connector. This illustration shows one type of a connector in which force is applied to the pressure element in a radial direction.
Figure 2 is essentially a sectional view along line 2--2 of Figure 1, except that, for the sake of clarity, Figure 2 illustrates a 5-pin connector.
Figure 3 is an exploded view of the female portion of the connector as illustrated in Figure 1.
Figure 4 is a fragmentary sectional view along line 4-4 of Figure 3 of the pressure element which converts mechanical force applied radially or axially and applies pressure to the split female conducting receptacles of the connector.
Figure 5 is a similar fragmentary sectional view of Figure 3 along 5-5.
Figure 6 is an enlarged fragmentary view in perspective of the receiving end of one of the split female receptacles.
Figure 7 is a sectional view of another type of a multiple-contact connector in which force may be applied to the pressure element in an axial direction. It furthermore illustrates another embodiment of this invention which may be practiced under certain conditions as more fully described below.
Referring now to Figures 1, 2 and 3 of the drawings, these illustrate the female and male portions of one type of a multiple-contact connector of the radial pressure type. Keyway l in conjunction with key 2 aligns the female and male portions for the purpose of polarizing the plug as is well known to those versed in the art. An outside shell 4 comprises the main body of the female portion of the connector. Ring 5 and slugs ll constitute a workable pressure actuator which has been found satisfactory in the practice of this invention, although other types of pressure actuators of suitable nature will doubtless be designed for this purpose by others skilled in the art. Rotation of the locking rings 5 having milled inner surfaces of a definite pitch forces these milled surfaces to bear on slugs ll loosely retained in slots l2 in the outside shell 4. Force is exerted radially on the outer surface of a pliable rubber bladder 13 in which split female conducting receptacles M are inserted. Alignment of these receptacles is maintained by spacers l composed of insulating material. Assembly may be completed in a number of rather obvious ways; Figure 3 shows assembly by mean of insulating spacers l5 and I6 and spring retaining rings l'la, [1b and Ho.
The operation of the pliable rubber bladder I3 may be explained by reference to Figures 4, 5 and 6. Longitudinal cylindrical receptacle tubes ill, of rubber or the like, are attached to flat perfo rated strips it, of rubber or the like, the joint 2!] between these parts being sealed by a vulcanizing or other suitable process. The orientation of these tubes l8 and the flat perforated discs I9 may be insured through the use of suitable jigs or forms, as is well known to those skilled in the art. Two such receptacle tubes are shown in Figures 4 and 5; any suitable number may be incorporated during the assembly operation. The last forming operation for the bladder consists in bonding a strip (not shown) of flexible material such as rubber peripherally about the flat perforated discs 19. The resultant space 2! may be completely filled with a fluid, preferably a liquid, such as distilled water, ethylene glycol, one of the silicones, or other such fluids. One'filling method may be accomplished through the use of two hollow needles similar to those used in hypodermic syringes; one to permit the escape of air a fluid is inserted, the other to provide the fluid. In the preferred structure of Figure 3, the pliable rubber bag l3 constructed as aforesaid, is constrained from moving after assembly in the female portion of the connector by a snug fit imposed by the outer shell 4, spacers i5 and It, and retainin rings ll. Force applied by slugs H radially to several portions of the outer surface of the pliable rubber bladder will tend to compress the hydraulic fluid. Since this fluid is practically non-compressible, pressure is exerted on the split female receptacles i l inserted in the tubes of the pliable bag 53 causing them to contract about the male conducting pins 3, thus forming an excellent electrica1 bond. Other methods of applying external force to the bladder may be utilraed, and this bag or bladder will serve to convert such selectively applied external force to a centripetal pressure on the split female receptacles.
Obviously precautions must be taken to prevent bladder leak so that the fluid, and hence the pressure, is not lost. In practice, very small hypodermic needles have been used in the fluid filling operation; the outer shell of the bladder efl'ectively sealing itself off when the needle was withdrawn. Additionally, the fluid in the bag or bladder may be selected so as to contain self-sealing ingredients, as is well known in the fabrication of bullet-proof gas tanks and puncture-proof tires; this will tend to heal any openings which may be formed during manufacture or subsequently during usage.
The use of split female receptacles as shown in Figure 6 allows ease of insertion of the solid male pins. As pressure is selectively applied the female pins are contracted insurin positive electrical contact.
In the axial pressure type of multiple-contact connector, a preferred form of the female portion of which is illustrated in Figure 7, the mating process is utilized to apply force to the pressure transmittin element. One method of effecting this pressure transmittal is accomplished by forcing the flat end of the male portion of the connector onto the first insulating spacer 30 on the input side of the female portion of the connector. At this point, the screw threads of retaining ring 22 would cause the male portion of the connector to advance. This motion will be imparted as a force to the spacer 3E! and hence the rubber element 23. Since this rubber element is constrained snugly by spacers 24, 25, and 26, spring retaining ring 21, and the outer shell 28, the force will be transmitted to the split female conducting receptacles 29. Thus the axial pressure type of connector causes a centripetal pressure to be exerted on the split female conducting receptacles as previously described.
The rubber element 23 of Figure 7 differs from the pliable rubber bladder 13 of Figure 3 in that no space is provided for a liquid. Such a rubber element may be formed through a simple molding operation. Such a rubber element would of necessity be flexible So that applied force would be transmitted and converted to a centripetal pressure on the split female conducting receptacles.
The precedin descriptions have detailed two methods of applying pressure: by radial and axial means. In addition, two types of flexible transmitting elements have been shown; one which utilize a pliable rubber bladder containing fluid, the other utilizes a flexible rubber element. Either of the above means of applying pressure may be coupled with either of the converter means so that applied force is converted to centripetal pressure on split female conducting receptacles. In addition, radial and axial means of applying force to the converter means could be utilized in combination to effect the desired result.
Such connectors could be fabricated in plate or strip form and could perform the function of interconnection between plug-in chassis and their housings commonly used for radio equipment. In this case, pressure might be applied by means of a plate bearing on the pressure transmitting element and actuated by the mechanical operation of the locking handles of the chassis.
This disclosure is written in terms of multiplecontact connectors since it is the belief of the inventor that such a device will enjoy its greatest use in this application. Such a device could be fabricated, however, with a single conducting element to provide the advantages discussed above.
In the appended claims, the Word hydrostatic should be construed to mean not only the type of pressure as applied through the medium of a. true fluid (such as 2i of Figure 5) but also the functional equivalent wherein such pressure is applied in the same manner by deformation of a substantially incompressible plastic member (such as 23 of Figure 7) since such a plastic has, for the purposes herein before set forth, substantially the same properties as a true liquid. Stated otherwise, such a plastic member, being tightly constrained, will resist any attempts to diminish its volume and thereby will cause the pressure applied to it to be transmitted in a hydrostatic manner to any other yielding portion such as, in this case, the included female receptacles 29. V
1. In' an electrical connector comprising one or more circuits therethrough, said one or more circuits each comprising a substantially rigid pin and a compliant receptacle, the improvement comprising a unitary enclosed fluid-filled chamber surrounding each of the compliant receptacles and capable of applying to each receptacle a force directed radially inwardly with respect to that receptacle, and means for selectively applying a force to at least one portion of the external surface of said chamber, whereby the application of such selective externally-applied force will cause the receptacles to be contracted tightly about the pins.
2. The device of claim 1, wherein said chamber comprises an enclosing material of a pliable but substantially non-porous substance defining a totally enclosed hollow space having a plurality of parallel passageways extending entirely therethrough, said hollow space being filled with a substantially incompressible liquid, and compliant receptacles inserted one in each of the passageways.
3. A device as in claim 1, in which the externally-applied force resulting in contraction of the receptacles may be selectively applied independently of any action tending to unite pin and receptacle.
4. A connector as in claim 1, in which the selectively externally-applied force required to produce a radially inwardly directed force of predetermined magnitude is independent of .the number of circuits through the connector,
ROBERT L. PERKINS.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 848,566 Nilsson Mar. 261, 1907 2,063,344 Schneider Dec. 8, 1936 2,265,341 Borchert Dec. 9, 1941 2,379,942 Webber July 10, 1945 2,404,682 Baker July 23, 1946 2,443,654 Else et al June 22, 1948