Receptacle terminal having retention means

Abstract: An electrical bussing assembly is shown including receptacle members (2) which are interconnectable with tab sections (64) by bus member (60). The receptacles include forward latching members (8), a intermediate contact member (12) and a rear locking member (14). The receptacle (2) is receivable over the tab portion (64) to a pre-assembled position where the forward latching member (8) cooperates with an aperture (68) of the tab contact (64). The receptacle (2) includes front tab portions (50) providing more stability to the receptacle in the preassembled position, and rear flat portions (55) providing an easier assembly for the operator.

Description: The invention relates to an electrical receptacle terminal of the type intended to receive a flat rectangular terminal tab. In particular, the invention is directed to a receptacle terminal which has a retention means to maintain the tab in various positions relative to the receptacle terminal. U.S. Patent Number 3,976,348 (U.S. Reissue Patent Number 30,277) discloses a stamped and formed electrical terminal receptacle which is dimensioned to receive a terminal tab having a rectangular cross section. The receptacle terminal is of the type having a web and sidewalls which extend from the marginal side portions of the web. The sidewalls are formed inwardly towards each other and towards the web so that a terminal tab can be inserted between the surface of the web and the free edge portions of the sidewalls. Terminals of this general type are widely used for the reason that they can be mated with standard terminal tabs having a rectangular cross section. The terminal receptacle described in U.S. Patent Number 3,976,348 has a tongue extending from the web at the tab receiving end of the receptacle. The tongue is reversely bent at the tab receiving end and has an intermediate portion which engages an inserted tab. The free end of the tongue extends beyond the receptacle section or portion of the terminal and is engageable so that it can be flexed towards the web. The intermediate portion of the tongue has a locking lance which is received in an opening in the tab which locks the tab to the terminal receptacle upon insertion. The tab can be disengaged by simply flexing the tongue towards the web portion of the terminal. Terminal receptacles having locking features are being used to an increasing extent on a variety of types of electrical equipment. Tab type terminals intended to be mated with receptacles as described above are manufactured in two standard widths, 4.7mm and 2.8mm. Heretofore receptacle terminals having locking lances have generally been manufactured for terminals having the greater width, for the reason that it is impractical to simply scale down or reduce the size of the receptacle and the locking lance so that the receptacle will accept a terminal tab having a width of 2.8mm. However, U.S. Patent Number 4,534,613 is directed to the achievement of a receptacle terminal which has a locking lance and which is dimensioned to receive the smaller standard tab therein. U.S. Patent Number 4,534,613 discloses a receptacle terminal which has a substantially flat web portion and contact springs which extend in one direction from the side edge portion of the web. The contact springs extend inwardly over the web and have end portions which are spaced from the web and which engage an inserted tab. A first pair of positioning ears are provided at the mating end of the terminal and extend inwardly of the web and towards each other. A second pair of positioning ears are formed from the contact springs and extend towards each other. The positioning ears locate a tab centrally on the web. A locking lance is struck from the web and serves to lock an inserted tab to the receptacle. This configuration allows the receptacle to cooperate with the smaller standard tabs (2.8mm). The locking lances described cooperate with the tab terminal when the tab is fully inserted or fully assembled into the receptacle terminal. However, in many instances it would prove benefical if any additional locking feature was provided which would maintain the tab terminal in a preassembled position relative to the receptacle terminal. U.S. Patent Number 3,633,156 discloses a tab receptacle formed from a sheet metal blank comprising a receptacle portion of generally channel cross section having a base and a pair of longitudinally covering sides, each side being formed with an elongate aperture for receiving a tab between the base and sides of the apertures remote from the base. U.S. Patent Number 3,183,471 discloses an electrical receptacle having a series of contact sections divided by a series of slots for easier insertion of the tab terminal into the receptacle. There is shown in international publication WO90/07805 an electrical terminal bus assembly of the type described having a first locking means proximate to the mating end with a second locking means to hold the tab portion in a fully connected position. While the design shown therein is commercially acceptable, there are improvements which could be made to this design to make it more desirable. First, the principle behind including a first locking means adjacent to the front mating end is to provide a low insertion force pre-assembled position, such that a worker can install the tabs into the pre-assembled position, and thereafter an assembly machine pushes the tabs into a fully locked position. It has been found that the insertion force into the first position is higher than what is desirable for the worker to push the tab into the first position. Secondly, when in the first position, the receptacle can have play on the tab as it is not well seated in the preassembled position. Finally due to the sheared surface at the rear of the receptacle, it is difficult for the workers to continuously push against this sheared end of the receptacle, without having their fingers and particularily their thumbs, becoming irritated. The objects of the invention were accomplished by providing an electrical receptacle terminal with the features of claim 1. By providing a front pre-locking section, the front section can include a lower insertion force thereby making it easier for insertion of the tab upon assembly. Also preferably the front pre-locking section includes a surface forward of a locking member, and has tab portions which are folded over to lie perpendicular to the insertion direction, which prevent the tab from pivoting in the receptacle while in the prelocked position. Furthermore, the rear locking section includes folded over flap members forming a planar surface, against which assembly personell can push with their thumbs, as opposed to pushing against a sheared edge. A preferred embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which; Figure 1 is a top view of a receptacle terminal in accordance with the present invention; Figure 2 is a side plan view of the receptacle terminal shown in Figure 1; Figure 3 is a cross sectional view taken through lines 3-3 of Figure 1; Figure 4 is a cross sectional view taken through lines 4-4 of Figure 2; Figure 5 is a front plan view of the receptacle shown in Figure 1 and 2; and Figure 6 is a top plan view of a bussing strip containing a plurality of tab terminals which can be interconnected to the receptacle shown in Figures 1 to 5. With respect first to Figure 1, a receptacle terminal according to the invention is shown generally at 2, and includes a mating receptacle section 4 and a wire connection shown at 6. The mating connecting section 4 is separated into three distinct sections, a first locking member 8 proximate to front mating end 10, a main contacting section 12 and a second locking member 14. The wire connecting section 6 is a conventional wire crimp in the preferred embodiment of the invention to include a crimp section shown generally at 16 and a strain relief section shown generally at 18. It should be understood that, while a wire crimping section is shown generally a 6, that an insulation displacement contact (IDC), or even a printed circuit board contact could be used in place of the wire crimp. As shown best in Figure 2 and 5, the electrical receptacle 2 includes a lower base portion 20 having two elongate ribs 22 and side walls shown at 24 which extend upwardly from marginal side edges of the lower base portion 20. Both of the side edges 24 are reversely bent about radiused portions 26 and are curled inwardly to form two side by side walls 30. As shown best in Figure 3, the wall 30 is separated by generally extending transverse slits 32 to form the various sections. As shown in Figure 3 the front preassembled locking element 8 is relatively short in length and includes a sheared edge at 36 and a camming edge 38 for leading the tab below the locking element 39, which is also provided with a locking surface at 40. The intermediate contacting section 12 includes a lead-in radiused surface at 42, a relief edge at 44, thereby forming contacting edges at 45 and 46. Finally, a rear locking element 51 is formed integral with the rear locking section 14 as shown best in Figure 3. With respect to Figure 5, the side walls 24 include integral tabs 50 which are folded towards one another to lie in a horizontal plane with respect to the base portion 20. Each tab portion 50 define a tab receiving opening 52 between the base portion 20 and the tab portions 50. With respect to Figures 1,3 and 4, the inner walls 30 include integral tab portions at 55 which are connected to the wall portions 30 via an integral web 56. The tab portions 55 are folded outwardly to lie adjacent to the sheared end edge 61 of the receptacle thereby forming planer surfaces against which a force can be manually exerted, as best shown in Figure 4. With respect now to Figure 6, a bus strip is shown generally at 60 to include a lengthwise commoning bar 62 and a plurality of tab terminals or contacts 64. The tab contacts include front mating edges 66 and locking apertures at 68. The insertion of terminal 2 over tab 64 is essentially a two step process. The first step consists of positioning a terminal 2 in alignment with the respective tab 64, and the terminal 2 is then partially inserted onto the tab 64, such that the tab is received in the receiving opening 52 of the terminal 2. As the tab progresses forwardly, the leading end of the tab 64 engages the lead in surface 38 on the locking element 39 thereby moving the prelocking element 8 upwardly to a position where the entire locking element 39 drops into the aperture 68 of the tab. In this position, rearwardly facing surface 40 prevents withdrawal of the tab holding the tab in place. Also in the position, the tab is held from pivoting about the locking element 39 due to edge 36, and tabs 50 at the front face of the receptacle 2. As the front locking element 8 is separated from the main contact element 12 by way of the slit 32 as shown in Figure 3, the insertion force due to overcoming the movement of the front locking element 8 is minimal, and can be carried out by hand. Further insertion of the tab 64 relative to the terminal 2 causes the front end of the tab 66 to contact the lead in surface 42 on the contacting section 12, in the rear edge 69 of the aperture 68 to contact the lead in section 38 on the front locking section 8 thereby assisting both the front locking section 8 and the contacting section 12 in an upper movement up over the tab member. A relief section at 44 defines distinct contact points at 45 and 46 for edge contact with the surface of the tab 64. Further continued movement rearwardly causes the front edge 66 of the tab to contact the lead in edge 49 of the rear locking member 14 moving the member 14 upwardly until rearwardly facing edge 51 overlies opening 68 whereupon the member 14 drops into the aperture 68 such that the edge of the aperture 68 abuts edge 51 on the rear locking member 14. Advantageously then, the receptacle contact 2 is made ergonomically better, by providing the tab portions at 55 which allows a flat planer surface against which the worker can press against, for example with his or her thumb. Secondly the insertion force of the receptacle over the tab, is reduced by making the preassembled latch portion 8 separate from the rest of the receptacle therefore requiring only deflection of a small length of the terminal wall portion 30. Finally, the tab is held relatively rigidly in its preassembled position, by being positioned between the base portion 20, against the edge 36, and being held downwardly by way of the tab portions 50. Furthermore, the roots 33 of the slots 32, and roots 35 of slot 34, extend outwardly to the sidewalls 24. This assures that each of the sections 4,12 and 14, can act independantly of each other during the insertion of the tab 64.

Claims: An electrical receptacle terminal (2) for receiving a tab terminal (64), the receptacle terminal (2) having a mating end (4) and a conductor connecting end (6), a base portion (20) extending from the mating end (4) to the conductor connecting end (6), the base portion (20) having resilient sidewalls (24) which extend therefrom and are formed inwardly towards each other and towards an inner surface of the base (20) to form two side by side walls (30), the sidewalls (24) have free edge portions (46) which are spaced from one surface of the base portion (20) by a distance which is less than the thickness of the tab terminal (64), the free edge portions (46) of the sidewalls being engageable against the tab terminal (64) upon insertion of the tab portion (64), the electrical receptacle terminal (2) being characterized in that: said receptacle has two transverse slots (32,34) which define three discrete sections, a front pre-locking section (8), an intermediate contact section (12) and a rear locking section (14), the slots (32,34) being formed in the two side by side walls (30), said prelocking section (8) has a locking member (39) which can cooperate with an aperture (68) on a mating tab terminal (64) and includes a surface (36) of the side by side walls (30) forward of said locking member (39) which is profiled to prevent the mating tab terminal (64) from pivoting , while in the prelocked position. The terminal of claim 1, characterized in that said front pre-locking section (8) further includes tab portions (50) which are folded over to lie perpendicular to the insertion direction, and profiled for the insertion of the tab beneath the tab portions (50) to prevent the pivoting movement of the tab (64), when in the prelocked position. The terminal of claim 1 or 2, characterized in that said front prelocking section (8) has a rearwardly facing shoulder (40) formed on the locking member (39). The terminal of any of claims 1-3, characterized in that said locking member (39) includes a ramped surface (38) profiled to assist lead-in of said tab member (64). The terminal of any of claims 1-4, characterized in that said forward end of said contact section (12) includes a lead in surface (42), profiled to assist said tab upon insertion past said locking member (39). The terminal of any of claims 1-5, characterized in that said contact section (12) includes contact points (45,46) along the length thereof. The terminal of any of claims 1-6, characterized in that said rear long section includes a forward lead in section (49) and a rearwardly facing shoulder (50) for said fully locked position. The terminal of any of claims 1-7, characterized in that said rear locking section (14) includes folded over flap members (55) forming a planar surface.

Inventors: HOTEA GHEORGHE, HOTEA, GHEORGHE
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1993
Main classification: H01R13
IPC codes: H01R13