US 3793612 A
A connector including a body having an integrally formed unitary hinge portion. The hinge portion connects a cover to a body member for relative movement to a closed position. As the cover is closed, material in the hinge portion deforms in at least two thin narrow strips of material at the bases of parallel grooves. Strain within each thin narrow strip is limited to a predetermined amount by the angle between walls defining the groove.
Description (OCR text may contain errors)
United States Patent [1 1 Driscoll Feb. 19, 1974 I CONNECTOR WITH UNITARY HINGE  Inventor: Aelred D. Driscoll, North St. Paul,
 Assignee: Minnesota Mining & Manufacturing Company, St. Paul, Minn.
 Filed: Mar. 2, 1972  Appl. No.: 231,230
 US. Cl 339/98, 16/150, l6/DIG. 13  Int. Cl H01r 13/38  Field of Search 339/59-61, 95,
339/97-99; 16/150, DIG. 13
 References Cited UNITED STATES PATENTS Elm 339/98 Enright et al. 339/97 R FOREIGN PATENTS OR APPLICATIONS 400,820 4/1966 Switzerland 16/150 Primary ExaminerJoseph I-I. McGlynn Attorney, Agent, or Firm-Alexander, Sell, Steldt & DeLaI-Iunt [5 7 ABSTRACT A connector including a body having an integrally formed unitary hinge portion. The hinge portion connects a cover to a body member for relative movement to a closed position. As the cover is closed, material in the hinge portion deforms in at least two thin narrow strips of material at the bases of parallel grooves. Strain within each thin narrow strip is limited to a predetermined amount by the angle between walls defining the groove.
4 Claims, 5 Drawing Figures UNITARY HINGE FIELD OF THE INVENTION This invention relates to electrical connectors of the type having integrally formed hinge portions.
BACKGROUND OF THE INVENTION Hinge portions integrally formed with the polymeric body parts of prior art connectors (e.g. US. Pat. Nos. 3,388,370 and 3, Ol2, 2 l9 can afford over 180 deg ees of relative movement between the body parts to attach the connector. This deformation occurs in a single thin strip of material generally defining the axis of rotation for the hinge portion. In polypropylene hinge portions this thin strip undergoes a strain hardening during its first deformation which improves its strength. After strain hardening the thin strip is highly resistent to fracture even if the connector parts are relatively moved over 180 degrees when the hinge portion is at a low temperature (i.e. below Fahrenheit). However, it has been found that if the first deformation of the thin strip occurs when the hinge portion is at a temperature of below 0 Fahrenheit, the incidence of fracture is relatively high. Such fracture detracts from the reliability of molded electrical connectors.
This problem can be averted during production by flexing the thin strip at room temperature before the connector is sold. This procedure, however, adds cost, and may leave the connector parts in unpredictable relative positions which may affect packaging efficiency and be inconvenient for a craftsman using the connector.
Additionally, certain countries have established flame resistent requirementsfor electrical connectors. These requirements have necessitated additives to polypropylene which detract from its favorable deformation characteristics, or have required the use of new materials. Many of these flame resistent materials do not possess the favorable deformation characteristics of polypropylene, so that even at room temperature they will not deform along a single thin strip of the material without fracturing to afford 180 degree relative motion between portions parts of the connector.
SUMMARY OF THE INVENTION An integrally formed hinge portion in a connector according to the present invention distrubutes bending strain within the hinge portion between two or more parallel, spaced thin strips of material, and limits bending within any one thin strip of material to a predetermined amount. The hinge portion can limit bending strain in a thin strip of a given material to an amount which will not produce fracture under anticipated use conditions so that connectors having hinge portions of polypropylene or less deformable materials need not be flexed during production even if they may be used in below zero conditions.
BRIEF DESCRIPTION OF THE DRAWING The invention will be more fully understood after reading the following description which refers to the accompanying drawing in which like numerals designate like parts throughout the figures, and wherein:
FIG. 1 is an enlarged fragmentary end view showing the unitary hinge portion of a connector according to the present invention with the hinge portion in an open position;
FIG. 2 is an enlarged fragmentary end view showing the unitary hinge portion of FIG. 1 with the hinge portion in a closed position;
FIG. 3 is a top plan view of the connector according to the present invention with an open cover attached by the hinge portion of FIG. 1;
FIG. 4 is an end view of the connector of FIG. 3; and
FIG. 5 is an end flew of the connector of FIG. 3 showing the cover in the closed position.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 3, 4, and 5 there is shown an electrical wire connector 46 according to the present invention having a hinge portion 12. The hinge portion 12 is integrally formed in the body of the connector 46 and connects a first part or cover 50 to a second part or body member 52 for 180 degree relative movement I from an open position (FIGS. 3 and 4) to a closed position (FIG. 5).
The hinge portion 12, body member 52 and cover 50 are one piece and formed of a deformable polymeric material such as polypropylene. When the body of the connector 46 is formed, (as by molding) a first surface on the cover 50 and a second surface 66 on the body member 52 are coplanar with the cover 50 and the hinge portion 12 in the open position FIGS. 1, 3 and 4. The hinge portion 12 includes a generally triangular axially extending hinge segment 28 having its apex 30 approximately in the plane defined by the surfaces 70 and 66 when they are coplanar. Two pairs of walls 26 define a pair of parallel V-shaped grooves 24 between the body member 52 and the cover 50. The wall 26 are generally of equal height, and a slight radius may be formed at the abase of each groove 24. The thickness of the hinge portion 12 at the base of each groove is not greater than 0.030 inch (preferably 0.015 inch) along precisely located narrow strips 32. The polymeric material in the strips 32 will deform to afford 180 degree relative movement of the cover 50 and the body member 52 from the open position to the closed position with the surfaces 66 and 70 in contact (FIGS. 2 and 5). The pair of walls 26 defining each groove 24 are disposed at a predetermined angle to each other when the surfaces 66 and 70 are coplanar. Relative movement of the cover 50 and the body member 52 toward the closed position will deform the material in a strip 32 until at least a portion of the walls 26 defining the associated groove 24 contact. Thus the angle between the walls 26 defining each groove 24 will determine the amount of bending strain which will occur in the corresponding-strip 32. As the hinge portion 12 is designed to afford 180 degree relative movement between the ea 6r ST and body member SZTt IIe wEIIs 26 defifiiiig" each groove 24 are disposed at about a degree angle to equally distribute the required strain in the hinge portion between the two strips 32 as may be'desirable to restrict fracture of the strips 32.
The connector 46 affords means for making an electrical connection between the ends of a pair of wires. The connector 46 includes a U-shaped conductive contact element 54 having spaced planar parallel legs 56 with parallel aligned slots formed therein to provide spaced wire engaging fingers 60. The insulative body member 52 is formed with a pair of parallel wire receiving cavities 62 extending into the body member 52 from inlet openings in the middle of an end wall 57 to an opposite end wall 58. The cavities 62 communicate through openings 64 with the top or first surface 66 of the body member 52 to afford inspection of the position of wires in the cavities 62. The body member 52 is formed with a pair of slots 68 extending transverse of the cavities 62 from the first surface 66 on the body member 52. The slots 68 slidably receive the contact element 54 for movement between a first position with the fingers 60 spaced from the cavities 62 to afford positioning the ends of wires therein (FIG. 4), to a second position within the slots 68 at which the fingers 60 may engage and electrically connect the ends of wires in the cavities. in its open position, the cover 50 is positioned with the inner surface 70 coplanar with and spaced from the first surface 66 to afford access to the contact element to move it to its second position (FlGS. 3 and 4). In the closed position of the cover 50 (FIG. 5), a flexible hook-like edge wall 72 parallel to and opposite the hinge portion 12 is in engagement over a lip 74, and the surfaces 66 and 70 are in contact with the cover 50 over the openings 64 and the end of the engaged contact element 54.
The connector 46 includes latching means to retain the cover 50 in the closed position. The precisely located lines of bending afforded by the strips 32 and contact of the walls 26 defining the grooves 24 provide accurate positioning of the edge wall 72 when the cover 50 has moved sufficiently close to the closed position that an arcuate surface 76 along the edge wall 72 will contact an arcuate surface 78 along the lip 74. Further pressure on the cover 50 to move it to its closed position will cause a camming action between arcuate surfaces 76 and 78 and deflection in the edge wall 72 and the hinge portion 48 so that the edge wall 72 will move over the lip 74 into latched engagement therewith to maintain the cover 50 in the closed position.
Hinge portions for connectors may include more than two hinge segments, however the maximum numher is limited as a practical matter by the ability to form the thin hinge segments. Within this limitation the number of strips 32 between which the strain should be divided in a hinge portion is determined primarily by the characteristics of the material in deformation and the angle of relative movement to be provided by the hinge portion.
Having thus described the present invention, what is claimed is:
1. In a connector for making an electrical connection between wires including a resilient conductive contact element having spaced wire receiving fingers, and an insulating body member of a polymeric material having wire receiving cavities and a slot extending from a first surface transverse to said cavities to slidably receive the contact element for movement from a first position spaced from the cavities to afford positioning wires therein, to an engaged position with the fingers extending across the cavities to engage wires therein; a cover having a second surface; a hinge portion integrally formed with and connecting the body member and the cover for movement of the cover from an open position with said surfaces spaced to afford manual movement of said connector element to the engaged position, to a closed position over the contact element with said surfaces in contact; and latch means for latching the cover in the closed position, the improvement wherein: said hinge portion has converging walls defining at least two spaced parallel grooves and an intermediate stiff hinge segment having a generally triangular shape in transverse section and extending parallel to said grooves, said segment being connected to the body member and the cover by thin narrow parallel strips of said polymeric material at the bases of the grooves; the strips being deformable by an extent limited by contact between the walls to afford movement of the cover to the closed position, and said latch means includes a lip along the edge of said first surface opposite said hinge portion, and a resilient hook-like edge wall projecting from said second surface along the edge thereof opposite said hinge portion and being adapted for latching engagement over said lip when said cover is in the closed position, said lip and edge wall each having an arcuate surface, and said arcuate surfaces being positioned as said cover is moved toward said closed position to engage each other to bias the cover away from said hinge portion to a position defined by engagement between the walls defining one of the said grooves, and to deflect said resilient edge wall to produce engagement thereof over said lip.
2. A connector according to claim 1, wherein said hinge portion has one hinge segment, and said walls are generally planar and define an angle between the walls of each groove of about degrees.
3. A connector according to claim 1, wherein said body member and cover are relatively movable through an angle of about degrees between said open and closed positions, and the walls are planar and define generally V-shaped grooves.
4. A connector according to claim 1, wherein said polymeric material is polypropylene, and said strips have a thickness no greater than about 0.03 inch.
UNE'EED STATES PA'lE'N'i ()FFKIE (l-E'Rii Fii'IA'HI OF (IORRECTEON Patent No. 3,193,61Q nawg ppruary 19. 197 6 IflV.nt0f(g) Aelred D. DI'iSCOll It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 1, change the title from "UNITARY HINGE" to CONNECTOR WITH UNITARY HINGE and line 49, change "distrubutes" to distributes Column 2, line 29, after "position" insert and after "1" insert line 36, change "wall" to walls and line 37, ohange "abase" to base Signed and sealed this 1st day of October 1974.
McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USC'OMM-DC 00370-99 n 0.5 GOVIIIIIIIIY "mime om'cl u'u o-au-nl.
FORM PC4080 (10-89)