Retainer for terminals in an electrical connector

Abstract: A retainer (10) for insertion into a connector housing of an electrical connector to retain electrical terminals in position in the housing, has a retainer body (11) and flexible locking bars (14F, 14R) for locking the retainer (10) to a connector housing (20) at two predetermined insertion positions thereof. The retainer body (11) comprises through-holes through which terminals are inserted, and engaging portions for preventing the terminals inserted into the connector housing from being moved in a return direction. The flexible locking bars (14F, 14R) form a part of and are co-planar with side walls of the retainer body (11), and are located within the extent of the through-holes in the retainer insertion direction. Each bar (14F, 14R) has a free end carrying a locking nose (16F, 16R). The locking noses (16F, 16R) are recessed into the retainer, relative to the outer faces of the side walls.

Description: The present invention relates to a retainer for insertion into a housing of an electrical connector to retain electrical terminals of the connector in position in the housing, and to an electrical connector having such a retainer. DESCRIPTION OF THE PRIOR ART An example of a retainer of the type described above will be described with reference to Figs. 7 and 8. This retainer has been placed on the market by the assignees of the present inventors. A similar retainer is disclosed in JP-A-7-245143. The retainer 1 has a plurality of parallel through-holes 3 in a body 2. A portion 4 for engaging an electrical terminal of the connector is formed at the front edge of the lower surface of each through-hole 3. Flexible locking bars 5F, 5R are formed in pairs as extensions of the side walls at opposite ends of the retainer body 2 in its right-to-left direction as seen in Fig. 9. The retainer 1 is inserted upwardly from below the connector housing 6 into a retainer-accommodating chamber 7 formed inside the connector housing 6, as shown in Fig. 10. A nose 8 formed at the upper end of each of the flexible locking bars 5F engages behind a projection 9F formed on a front wall of the retainer-accommodating chamber 7. (Front and rear here refer to the front and rear of the connector itself) In this manner, the retainer 1 is temporarily locked in a first position in the connector housing 6, as shown in Fig. 10. Terminals (not shown) are inserted into respective cavities (not shown) of the connector housing 6 to penetrate through the respective through-holes 3 of the retainer, the through-holes 3 being aligned with the cavities in the connector housing 6. Then, the retainer 1 is pressed further upward into the retainer-accommodating chamber 7. As a result, a nose 8 on each locking bar 5R engages a corresponding projection 9R, thus locking the retainer 1 at a second position in the connector housing 6, with each engaging portion 4 engaging the corresponding terminal. In this manner, each terminal is retained in the connector housing 6 at the predetermined position.. The flexible locking bars 5F and 5R projecting upward from the retainer body 2 increase the height of the retainer 1 by the height of the bars 5F and 5R. JP-A-5-144499 (Japanese Laid-Open patent application) discloses a similar retainer having locking noses for holding the retainer at two insertion positions in the connector housing. At each end of the retainer body, one locking nose is a simple projection on the side wall and is therefore not resiliently depressible, while the other locking nose is at an intermediate position on a bar-shaped portion of the side wall which is fast with the remainder of the side wall at both of its ends. US-A-5252096 describes another such retainer which has, at each end, overlapping its side wall bounding the terminal-receiving through-holes, a curved wall portion carrying two flexible locking bars having free ends carrying locking noses at respectively different height positions to provide two insertion positions of the retainer in the housing. The arrangements of the locking bars and locking noses in these retainers have defects, in that they project excessively from the retainer which is undesirable since it increases the overall size of the connector or they are not sufficiently flexible to permit easy insertion. There is also a risk in some cases of damage to the locking bars during transport or handling, or on mis-aligned insertion of the retainer into the connector housing. DE-A-4229279 discloses another terminal retainer which has locking bars at each end, in the same plane as side walls of the end most terminal-receiving through-holes. The locking bars have a height grater than that of the through-holes and have their free-ends trailing with respect to the insertion direction of the retainer. SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art. It is accordingly an object of the present invention to provide a compact retainer. It is a further object to provide a retainer in which risk of damage to the locking bars is minimized. According to the invention, there is provided a retainer for insertion into a housing of an electrical connector, as set out in claim 1. In the invention, because the height (in the retainer insertion direction) of each of the flexible locking bars is smaller than that of the retainer body and the bars are within the height extent of the retainer's through-passages, the length of the retainer in the direction in which the retainer is inserted into the connector housing, i.e. the height of the retainer, is smaller than in the device of Figs. 9 and 10. Accordingly, the vertical dimension of the connector housing (dimension in the insertion direction) is smaller. The risk of accidental damage to the locking bars is also reduced. Since the locking bars are part of the side walls and co-planar therewith, the width of the retainer, and therefore the connector housing is minimized. Nevertheless, the locking bars, which extend in cantilever manner to their free second ends, are sufficiently flexible. Preferably each locking nose is recessed into the retainer, relative to the outer face of the side wall. This reduces the risk of breakage of the locking bar if the retainer is not perfectly aligned during insertion into the housing, particularly in the case where the second end of the locking bar is the leading end in the direction of insertion into the housing. The present invention also consists in an electrical connector having the retainer as described above in combination with the connector housing and the electrical terminals. BRIEF INTRODUCTION OF THE DRAWINGS These and other optional features and advantages of the present invention will become clear from the following description of embodiments thereof, given with reference to the accompanying drawings throughout which like parts are designated by like reference numerals. In the drawings: Fig. 1 is a sectional view showing a retainer, which is a first embodiment of the present invention, temporarily locked in a first position in a connector housing; Fig. 2 is a sectional view showing a state in which the retainer of Fig. 1 has been finally locked to the connector housing; Fig. 3 is a side view showing the retainer of Fig. 1; Fig. 4 is a front view showing the retainer of Fig. 1; Fig. 5 is a sectional view showing in detail a state in which flexible locking bars of the retainer of Fig. 1 are at a temporary locking position in the connector housing; Fig. 6 is a sectional view showing in detail a state in which the flexible locking bars of the retainer of Fig. 1 are at a final locking position in the connector housing; Fig. 7 is a front view showing a conventional retainer; and Fig. 8 is a sectional view showing a state in which the conventional retainer of Fig. 7 has been temporarily locked to a connector housing. DESCRIPTION OF THE PREFERRED EMBODIMENT The retainer according to the embodiment of the present invention is shown in Figs. 1 to 6. A connector housing 20 in which the retainer 10 of the first embodiment is mounted will be described first. As shown in Figs. 1 and 2, the connector housing 20 has a plurality of cavities 21 through it in the front-to-rear direction thereof (left-to-right in Fig. 1). The cavities 21 are arranged in three tiers, namely, an upper tier, a middle tier, and a lower tier. Eight cavities 21 are formed at regular intervals in the intermediate and lower tiers in the connector housing 20, and four cavities (not shown) are present in the upper tier. In the upper tier two cavities are formed at each end in the side-to-side direction (perpendicular to Fig. 1). Metal electrical terminals (not shown) are inserted forwardly into the respective cavities 21 in a direction from the rear of the connector housing 20. When each terminal has been pressed forward to a predetermined position in each cavity 21, a latch 22 of each cavity 21 prevents the terminal from being moved rearwardly. In the connector housing 20, there is formed a retainer-accommodating chamber 23 into which the retainer 10 is inserted upward from the bottom of the connector housing 20. The retainer-accommodating chamber 23 is open at its lower side and communicates with the respective cavities 21. When the retainer 10 has been fully inserted into the retainer-accommodating chamber 23 as described below, the retainer 10 engages the terminals inserted into the respective cavities 21 at the predetermined position thereof, thus preventing the terminals from being moved rearwardly. The construction of the retainer 10 will now be described. The retainer 10 has a body 11, molded in one-piece of suitable plastics material, with a plurality of through-holes 12 formed in its front-to-rear direction; a plurality of terminal engaging portions 13; and pairs of front and rear flexible locking bars 14F and 14R formed as parts of the lateral side walls thereof. The body 11 comprises a lower tier insertion section 11L and a pair of upper tier insertion sections 11U. The lower tier insertion section 11L has eight through-holes 12 penetrating through the body 11 in its front-to-rear direction and aligning with the eight cavities 21 of the lower tier of the connector housing 20, respectively, in the assembled state. Each upper tier insertion section 11U has two through-holes 12 formed through the body 11 in its front-to-rear direction such that the right-hand two through-holes 12 align with the two cavities 21 positioned at the right-hand side of the intermediate tier of the connector housing 20, whereas the left-hand two. through-holes 12 align with the two cavities 21 positioned at the left-hand side of the intermediate tier of the connector housing 20. As shown in Fig. 4, engaging portions 13 for the terminals are formed at the front end of the lower surface of each of the eight through-holes 12 (lower tier) and four through-holes 12 (intermediate tier). Engaging portions 13a are formed at the front end of the upper surface of the lower tier insertion section 11L, in correspondence to the middle four cavities 21 of the middle tier of cavities of the connector housing 20. Engaging portions 13b are formed at the front end of the upper surface of the upper tier insertion sections 11U in correspondence to the respective four cavities 21 of the upper tier of the connector housing 20. Each engaging portion 13, 13a, 13b engages the lower surface of each terminal inserted into the predetermined position of the respective cavity 21, thus preventing it from moving rearwardly, in the assembled connector. The front and rear flexible locking bars 14F and 14R serve as means for selectively holding the retainer 10 at a temporary locking position and at a final locking position in the retainer-accommodating chamber 23. The front and rear flexible locking bars 14F and 14R each form a part of the right or left end side walls of the lower tier insertion section 11L of the body 11. These side walls have planar outside faces which are parallel to the direction of insertion of the retainer into the connector housing 20. The outside faces of the locking bars 14F, 14R are thus co-planar with the remainder of the side walls. The inside faces of the side walls are faces of the end-most through-holes of the array of through-holes 12. A pair of front and rear inverted L-shaped cut-outs 15F and 15R is formed in each of the -side walls of the lower tier insertion section 11L and open respectively at the front and rear edges of the side walls. There are thus formed a pair of the front flexible locking bars 14F at the front of the lower tier insertion section 11L and a pair of the rear flexible locking bars 14R at the rear thereof. The front and rear flexible locking bars 14F and 14R are cantilever-shaped, extending upward, i.e. in the direction in which the retainer 10 is inserted into the retainer-accommodation chamber 23, from ends fast with the remainder of the side walls to free ends which are supported only by the bars themselves. As shown in Fig. 4, each of the front and rear cut-outs 15F and 15R penetrates through to the end-most through-holes at the left and right ends of the eight through-holes 12 of the lower tier of the connector housing 20. Thus, the front and rear flexible locking bars 14F and 14R flex elastically in the front-to-rear direction of the retainer body 11. The front flexible locking bar 14F (left-hand side in Figs. 5 and 6) serves as a means for temporarily locking the retainer 10 to the connector housing 20. A front temporary locking nose 16F projecting forward from the free (upper) end of the front flexible locking bar 14F engages a temporary locking projection 24 formed on the front wall of the retainer-accommodating chamber 23, with the front temporary locking nose 16F located above the temporary locking projection 24. The rear flexible locking bar 14R (right-hand side in Figs. 5 and 6) serves as a means for both temporarily and finally locking the retainer 10 to the connector housing 20. A rear locking nose 16R projecting rearward from the free (upper) end of the rear flexible locking bar 14R engages a locking projection 25 formed on the rear wall of the retainer-accommodating chamber 23, with the rear locking nose 16R located below the locking projection 25 in the temporary locking state and above the locking projection 25 in the final locking state. As Fig. 4 shows, the locking noses 16F are set back from the outer surfaces of the side walls of the retainer, i.e. are slightly recessed towards the interior of the retainer. The same applies for the locking noses 16R. The operation of the embodiment will now be described. The retainer 10 is inserted into the retainer-accommodating chamber 23 of the connector housing 20 to lock it to the connector housing 20 in the temporary locking state before electrical terminals are inserted into the connector housing 20. When the retainer 10 is inserted upward into the retainer-accommodating chamber 23 from the lower surface of the connector housing 20, each front temporary locking nose 16F moves past the temporary locking projection 24 of the retainer-accommodating chamber 23, with the front flexible locking bar 14F elastically flexing backward. Then, the front flexible locking bar 14F restores elastically to its original state. As a result, the front temporary locking nose 16F engages the upper part of the temporary locking projection 24 and at the same time, the rear locking nose 16R of the rear flexible locking bar 14R engages the lower part of the locking projection 25. Consequently, as shown in Figs. 1 and 5, the retainer 10 is held in the temporary locking state. In the temporary locking state, the through-holes 12 of the lower tier insertion section 11L register with the cavities 21 of the lower tier of the connector housing 20; the through-holes 12 of the upper tier insertion section 11U register with the cavities 21 at the right and left ends of the intermediate tier of the connector housing 20; the upper surface of the lower tier insertion section 11L is positioned at the same level as that of the bottom surface of the cavities 21 of the intermediate tier of the connector housing 20; the upper surface of the upper tier insertion section 11U is positioned at the same level as that of the bottom surface of the cavities 21 of the upper tier of the connector housing 20; and each engaging portion 13, 13a, 13b of the retainer 10 is flush with the bottom surface of the respective cavity 21. In this state, the terminals (not shown) are inserted into the respective cavities 21 from the rear of the connector housing 20. After all terminals are inserted to the predetermined position thereof, the retainer 10 is pressed upward further. As a result, the rear locking noses 16R move past the locking projection 25, with the rear flexible locking bars 14R flexing elastically inward (forward). When the rear flexible locking bar 14R is restored elastically to the original state, the rear locking nose 16R engages the upper part of the locking projection 25. Consequently, as shown in Figs. 2 and 6, the retainer 10 is held in the final locking state. In the final locking state, each engaging portion 13, 13a, 13b of the retainer 10 engages the rear side of each terminal inserted into each cavity 21 at the predetermined position thereof, thus preventing the terminal from moving-backward from the predetermined position, providing positive holding of the terminals in addition to the effect of the latches 22. As described above, in the first embodiment, the front and rear flexible locking bars 14F and 14R for locking the retainer 10 at the temporary locking position and the final locking position, respectively form portions of the right or left side walls of the lower tier insertion section 11L of the retainer body 11. Therefore, the height of the retainer 10 is not larger than the height of the array of cavities in the connector housing 20. Accordingly, the height of the retainer-accommodating chamber 23, which influences the height of the connector housing 20, is minimized. Thus, the present invention provides a compact connector housing. Because the front and rear flexible locking bars 14F and 14R do not project from the body 11, neither in the upward direction nor from the side walls, the risk that they are broken when the device is handled is minimized. The recessing of the locking noses also minimizes risk of damage, on insertion of the retainer into the onnector housing 20. In this embodiment, the front and rear flexible locking bars 14F and 14R form a part of the right or left side walls of the retainer, i.e. the side walls of the endmost through-holes of the array of through-holes of the retainer. That is, the thickness of the front and rear flexible locking bars 14F and 14R is equal to that of the side walls of the retainer 10. Accordingly, in the right-to-left (side to side) direction of the retainer 10, the retainer 10 is smaller than that of a retainer having its flexible locking bars located outside the side walls. If the front and rear flexible locking bars 14F and 14R are not cantilever-shaped, but have upper and lower ends continuous with upper and lower parts of the end walls of the retainer body, the locking nose of the flexible locking bar should be formed at its center so that it flexes in a possible greatest amount in order to allow the locking bar to lock the retainer to the connector housing reliably. In this case, the length between the fulcrum of the flexure of the flexible locking bar and the locking bar is half of the length of the bar. Therefore, the flexible locking bar of this construction flexes by a smaller amount than the cantilever-shaped one according to the first embodiment. Thus, it is necessary to make the flexible locking bar longer than the one according to the first embodiment to enable it to flex sufficiently. Consequently, it is necessary to form a large retainer. Unlike the above-described construction, the front and rear locking noses 16F and 16R are carried at the free (upper) end of each of the front and rear flexible locking bars 14F and 14R in the manner of a cantilever. Thus, even though the length of each of the front and rear flexible locking bars 14F and 14R is short, the front and rear locking noses 16F and 16R can be reliably flexed in the front-to-rear direction of the retainer 10. The present invention is not limited to the above-described embodiment, but the variations described below are included in the technical scope of the present invention. (1) In the embodiment, the retainer to be applied to the connector housing in which terminal-receiving cavities are formed in three tiers has been described. In addition, it is possible to apply the retainer of the present invention to a connector housing having a single tier in which cavities for the electrical terminals are arranged in a single row and to connector housings having two tiers or more than three tiers in which the cavities are arranged. When cavities are formed in one or two tiers in the connector housing to which the retainer is applied, the upper tier insertion section is removed from the retainer body shown in Figs. 1 to 6. In this case the flexible locking bars do not project upward from the side walls of the retainer body because the height of each of the flexible locking bars is within the height of the side walls of the lower tier insertion section. (2) In the embodiment, the flexible locking bars, apart from their locking noses, do not project from the front and rear walls of the lower tier insertion section. It is possible to form the front and rear flexible locking bars so that they project forward and rearward respectively from the front and rear walls of the retainer body.

Claims: A retainer (10, 30) for insertion into a housing (20) of an electrical connector in order to retain electrical terminals in position in said housing, said retainer having a retainer body having a front face and a rear face and two opposite side walls having planar outside faces and further having a plurality of through-holes (12) through which said electrical terminals extend in the assembled state of the retainer in the connector, said through-holes (12) being arranged in an array and extending through the retainer in a first direction from said front face to said rear face, said retainer further having engaging portions (13) for engaging said terminals to hold them in position in said through-holes when in said assembled state, said retainer being in use inserted into the connector housing in a second direction, which is perpendicular to said first direction, said side walls being parallel to said second direction and each said side wall bounding an adjacent one of said through-holes (12), said side walls providing, for locking the retainer in said housing (20), a plurality of resiliently flexible locking members (14F, 14R), each said locking member (14F, 14R) being a portion of said side wall and being constituted by a flexible bar having an outer face which is co-planar with the remainder of said side wall and has a first end fast with the remainder of said side wall and a second end having a locking nose (16F, 16R) which in use engages in a latching manner with said connector housing (20), said second end being free and unsupported otherwise than by said bar, characterized in that each said locking member (14F, 14R) is of a size such that its extent in said second direction is less than and is contained within the overall extent of said array of said through-holes (12) in said second direction, and each said bar of said locking members (14F, 14R) is arranged so that its said second end is closer than its said first end to the leading end face of the retainer when said retainer is inserted into said housing in said second direction during assembly of the retainer and the housing (20). A retainer according to claim 1 wherein each said locking nose (14F, 14R) is recessed into the retainer with respect to said planar outer face of the side wall. An electrical connector comprising a housing (20) having a plurality of cavities (21) arranged in an array and extending through it in a first direction; a plurality of electrical terminals inserted in said cavities (21); a retainer (10) according to claim 1 or 2 inserted into said housing (20) and locked in said housing (20) by its locking members (14F, 14R) said retainer holding said terminals in position in said housing.

Inventors: MAKINO HIROTAKA, MAKINO, HIROTAKA, Makino, Hirotaka, c/o Sumitomo Wiring Systems Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1997
Main classification: H01R13
IPC codes: H01R13