Metal terminal insertion tool for inserting a metal terminal within a connector housing

Abstract: To facilitate the insertion of a metal terminal with a waterproof seal into a cavity, a tool is provided with a stepped tubular portion and a grip portion connected to the tubular portion. The stepped tubular portion has, in one embodiment, four cylindrical portions having different outer diameters, and the outer diameters decrease stepwise toward a distal end of the tubular portion. A slit is formed in the tubular portion and extends from the distal end thereof into the fourth cylindrical portion. The slit has a width so as to allow a wire to pass therethrough. With this construction, the distal end of the cylindrical portion can easily push the waterproof seal without deformation.

Description: BACKGROUND OF THE INVENTION This invention relates to a metal terminal insertion tool for mounting a waterproof seal into a waterproof connector housing. Generally, a waterproof seal used in a waterproof connector is made of rubber and is fixedly secured, together with a wire, to a metal terminal by compressive clamping. When the metal terminal is inserted into a cavity in a connector housing while holding the wire by hand, the waterproof seal is also inserted into the cavity and brought into intimate contact at its outer periphery with an inner surface of the cavity, thereby forming a watertight seal. During insertion of the metal terminal, when the waterproof seal begins to be press-fitted into the cavity, a large frictional resistance to movement of the waterproof seal is suddenly encountered. Therefore, when pushing the metal terminal into the cavity while holding the wire merely with the fingers, the narrow wire is often bent or buckled, so that the metal terminal and the waterproof seal cannot be easily brought into their respective proper positions. As a result, the entire assembly is held in an incompletely inserted position, and the waterproof seal is inserted in a tilted manner. This causes incomplete retaining of the metal terminal and incomplete watertight sealing. To prevent this, it has heretofore been necessary to push the waterproof seal deep into the cavity using a narrow, bar-like tool, such as a precision screw driver, to bring the waterproof seal and the metal terminal into their respective proper positions. However, in the operation in which the above narrow, bar-like tool is used, the point of application of the force on the peripheral portion of the waterproof seal must be sequentially adjusted to ensure proper fitting of the seal. This is a time-consuming and troublesome operation. Further, DE-U-83 33 705 discloses an insertion tool according to the first part of claim 1 for inserting an electrical terminal which comprises a slit extending through the entire insertion tool. The insertion tool has a joint causing a flexibility of the insertion tool in axial direction to avoid damages of the walls of an insertion chamber, if an insertion tool is not in axial alignment with the walls of the insertion chamber, while inserting the metal terminal with a wire. Moreover, US-A-3,871,057 discloses an inserting tool cooperating with a face of a waterproof seal. The insertion tool comprises a double ended rod member which has a reduced diameter on one end on which the interface seal is installed and then transferred to the specific pin contact on which the seal is installed. SUMMARY OF THE INVENTION The present invention has been made in order to overcome the above problems, and an object of the invention is to provide a metal terminal insertion tool by which metal terminals with respective waterproof seals can be easily pushed into their respective cavities. The above object has been achieved by a metal terminal insertion tool according to claim 1 that includes a tubular portion engageable with a waterproof seal at a distal end thereof. The tubular portion has a slit extending from the distal end thereof, the slit having such a width that the slit can receive a wire therein. The tubular portion has a stopper for limiting the depth of insertion of the tubular portion into an insertion passage. The tubular portion can have a stepped configuration such that an outer diameter of the tubular portion is reduced stepwise toward its distal end. For mounting a metal terminal in a connector housing, the wire is first held by the fingers, and is inserted into a cavity, so that the waterproof seal (integrally connected to the metal terminal) is fitted into the cavity. Then, the tool is held by the hand, and the wire is received into the bore of the tubular portion through the slit in the tubular portion, and the distal end of the tubular portion is brought into engagement with the waterproof seal. The tubular portion is pushed into the cavity, so that the entire waterproof seal is pushed in one motion into the cavity together with the metal terminal. It is also possible that the metal terminal and its associated waterproof seal are first attached to the tool, and the entire assembly is inserted into the connector housing. The stopper provided on the tubular portion limits the depth of insertion of the tubular portion. Therefore, when the waterproof seal reaches its proper position, the stopper prevents the tubular portion from being pushed in further. When the tubular portion has a stepped configuration such that its outer diameter is reduced stepwise toward its distal end, if the distal end portion of the tubular portion is cut off, the diameter of the distal end of the tubular portion can be increased. Furthermore, the diameter of the distal end can be varied in a stepped manner. Therefore, by cutting the distal end portion of the tubular portion at a suitable position, the diameter of the distal end of the tubular portion can be determined in accordance with the outer diameter of the waterproof seal and the inner diameter of the cavity. As described above, in the present invention, the distal end of the tubular portion can push the waterproof seal uniformly over substantially the entire peripheral portion thereof, and therefore the waterproof seal can be pushed in straight, thereby enhancing a waterproof effect. Moreover, it is not necessary to change the position of pushing of the waterproof seal sequentially around the outer peripheral portion thereof so that the waterproof seal will not be deformed or tilted at a localized portion thereof as in the conventional construction. Instead, it is only necessary to push the tubular portion in one motion into a predetermined position. This achieves an advantage that the efficiency of the operation is very good. In addition, the stopper prevents the waterproof seal from being excessively pushed, so that a constant quality can be secured. Moreover, by cutting the tubular portion at a suitable portion thereof, the distal end of the tubular portion can be determined in accordance with the outer diameter of the waterproof seal and the inner diameter of the cavity. Therefore, the tool is suitable for installation of many different types of connectors. These and other aspects and advantages of the present invention are described in or apparent from the following detailed description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments are described with reference to the drawings in which: Fig. 1(A) is a side-elevational view showing an overall construction of a first embodiment; Fig. 1(B) is a front-elevational view of the first embodiment; Fig. 2 is a perspective view showing an initial stage of the insertion of a metal terminal in the first embodiment; Fig. 3 is a cross-sectional view showing a condition in which the insertion of the metal terminal is finished; Fig. 4(A) is a side-elevational view showing an overall construction of a second embodiment having a flange; Fig. 4(B) is a front-elevational view of the second embodiment; Fig. 5(A) is a side-elevational view showing an overall construction of a third embodiment having a two-step configuration; Fig. 5(B) is a front-elevational view of the third embodiment; Fig. 6(A) is a side-elevational view showing an overall construction of a fourth embodiment having one projection; Fig. 6(B) is a front-elevational view of the fourth embodiment; Fig. 7(A) is a side-elevational view showing an overall construction of a fifth embodiment having two projections; Fig. 7(B) is a front-elevational view of the fifth embodiment; Fig. 8(A) is a side-elevational view showing an overall construction of a sixth embodiment having four projections; Fig. 8(B) is a front-elevational view of the sixth embodiment; and Fig. 9 is a side-elevational view showing an overall construction of a seventh embodiment having a tapered tubular portion. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A first embodiment of the present invention will now be described with reference to Figs. 1 to 3. A metal terminal insertion tool of this embodiment is used for inserting a metal terminal with a waterproof seal into a connector housing of a waterproof connector. Reference is first made to the waterproof connector used in connection with the present invention. As shown in Fig. 3, the connector housing 1 is of a conventional construction and includes a hood portion 2 for receiving a mating connector, a lock portion 3 for locking engagement with the mating connector, a waterproof seal 4 for the housing, and a cavity 5. One end of the cavity 5, remote from the hood portion 2 of the connector housing 1, defines an insertion port 7a for the passage of the metal terminal 6 therethrough, and the cavity 5 has an insertion passage 7 and a terminal receiving chamber 8 disposed inwardly of the insertion passage 7 for receiving the metal terminal 6. The metal terminal 6 is of a conventional construction, and includes an insulation barrel 10 for gripping an insulating sheath of a wire 9 and a wire barrel 11 for gripping a conductor of the wire 9. The insulation barrel 10 is compressively deformed against the waterproof seal 12 to grip the insulating sheath, the waterproof seal 12 being press-fitted into the cavity 5. The metal terminal insertion tool of this embodiment includes a grip portion 13, and a stepped tubular portion 14 extending from one end of the grip portion 13, as shown in Figs. 1(A) and 1(B). The metal terminal insertion tool is made of a synthetic resin having a hardness such that it can be cut off using a cutter or the like. The stepped tubular portion 14 has four cylindrical portions 14a to 14d having different outer diameters. The outer diameters decrease in size in a direction from the grip portion 13 towards the distal end 100 of the tubular portion 14. A slit 15 is formed in the tubular portion 14, and axially extends from the distal end 100 into the fourth cylindrical portion 14d. The slit 15 has a width so as to allow the wire 9, which is connected to the metal terminal 6, to pass through the slit 15 (Figure 2). A method for mounting the metal terminal 6 using the metal terminal insertion tool will now be described. For inserting the metal terminal 6 into the terminal receiving chamber 8 in the connector housing 1, the wire 9 connected to the metal terminal 6 is first held by the fingers, and the terminal 6 is inserted into the insertion passage 7 through the insertion port 7a, so that the waterproof seal 12 is located near the insertion port 7a. A portion of the wire 9 extending towards the outside of the waterproof seal 12 is received into the bore of the tubular portion 14 through the slit 15. Accordingly, the wire 9 is introduced into the distal end 100 of the tubular portion 14, and the distal end 100 of the tubular portion 14 is abutted against the waterproof seal 12 (see Fig. 2). At this time, since the wire 9 is received in the tubular portion 14, the distal end of the tubular portion 14 can be held against the waterproof seal 12 uniformly over substantially the entire peripheral portion thereof. Then, the grip portion 13 is pushed towards the metal terminal 6 to force the waterproof seal 12 deep into the cavity 5, so that the metal terminal 6 moves along the insertion passage 7 and becomes received in the terminal receiving chamber 8. In this case, by merely pushing the tubular portion 14 deep into the insertion passage 7, the waterproof seal 12 can be inserted straight without being tilted, so that the outer peripheral surface of the waterproof seal 12 is held in intimate contact with the inner peripheral surface of the insertion passage 7, thereby achieving a good sealing effect. In the case where the inner diameter of the insertion passage 7 of the cavity 5 is larger than the outer diameter of the cylindrical portion 14a, and is smaller than the outer diameter of the cylindrical portion 14b, the cylindrical portion 14b is brought into engagement with the peripheral edge portion of the insertion port 7a in the connector housing 1 to form a stop by limiting the depth of insertion of the tubular portion 14 when the metal terminal 6 is received in the terminal receiving chamber 8 and upon full insertion of the cylindrical portion 14a into the insertion passage 7, as shown in Fig. 3. Therefore, the waterproof seal 12 is prevented from being excessively pressed, and the metal terminal 6 and the waterproof seal 12 can be positively pushed into their respective proper positions without fail. If the inner diameter of the insertion passage 7 is larger than the outer diameter of the cylindrical portion 14b, and is smaller than the outer diameter of the cylindrical, portion 14c, the cylindrical portion 14c is brought into engagement with the connector housing 1 to limit the depth of insertion of the tubular portion 14. Thus, in this embodiment, when forcing the waterproof seal 12 into the cavity, the distal end of the tubular portion 14 can simultaneously push the entire circumference of the waterproof seal 12, and therefore the waterproof seal can be inserted straight, thereby achieving a high waterproof effect. Moreover, because the entire waterproof seal 12 is pushed in one motion, it is not necessary to change the position of pushing of the waterproof seal 12 sequentially around the outer peripheral portion thereof as in the conventional construction. Instead, it is only necessary to push the tubular portion 14, and therefore the operation can be carried out easily. Furthermore, in this embodiment, the tubular portion 14 has a stepped configuration, and when the metal terminal 6 is pushed into the proper position, the cylindrical portion 14b is abutted against the edge portion of the insertion port 7a in the connector housing 1. Therefore, it is only necessary to push the tubular portion 14 until the cylindrical portion 14b is brought into engagement with the above edge portion, so that good efficiency of the operation is achieved. Because the tubular portion 14 has a hardness such that it can be cut off, the tubular portion 14 can be cut in accordance with the outer diameter of the waterproof seal 12 or the inner diameter of the insertion passage 7. For example, if the outer diameter of the waterproof seal 12 is slightly larger than the outer diameter of the cylindrical portion 14b, the cylindrical portion 14a can be cut off from the tubular portion 14, and the waterproof seal 12 can be pushed by the cylindrical portion 14b. Namely, a suitable one of the cylindrical portions that has an appropriate diameter can be selected in accordance with the outer diameter of the waterproof seal 12. Moreover, the tubular portion 14 can be cut off in accordance with a predetermined depth of insertion thereof, and therefore even if the depth of insertion is different from that mentioned in the above embodiment, the next-stage cylindrical portion can effectively function as a stopper. Therefore, many kinds of connectors can be dealt with using one kind of tool. The present invention is not limited to the above embodiment and the following modifications can be made, which fall within the scope of the invention. (1) In the first embodiment, the tubular portion 14 has a stepped configuration and the cylindrical portion 14b functions as a stopper for limiting the depth of insertion of the tubular portion 14. However, such a construction as shown in Figs. 4(A) and 4(B) may be adopted. A tubular portion 21, having a uniform diameter throughout its length from its distal end to its proximal end, extends from one end of a grip portion 24, and a flange 22 is formed on a predetermined portion of the tubular portion 21 spaced from the distal end thereof. This flange 22 serves as a stopper. A slit 23 is formed in the tubular portion 21, and extends from the distal end of the tubular portion to a generally central portion thereof through the flange 22. The slit 23 can receive the wire, which is clamped to the metal terminal together with the waterproof seal. The waterproof seal can be easily pushed by this tool without deforming the seal by the distal end of the tubular portion 21. Therefore, advantageously, a waterproof effect can be enhanced. Also, the efficiency of the operation can be enhanced, as in the first embodiment. In addition, the flange 22 can be adjustably mounted in fixed position to fix the terminal insertion depth. (2) In the first embodiment, although the tubular portion 14 has the stepped configuration, that is, the four cylindrical portions are different in outer diameter, the number of these steps is not limited to four, and such a construction as shown in Figs. 5(A) and 5(B) may be adopted. A tubular portion 31, having two cylindrical portions of different outer diameters, extends from one end of a grip portion 33, and is narrowed stepwise toward the distal end thereof. A slit 32 is formed in the tubular portion 31, and extends from the distal end of the cylindrical portion 31a into the cylindrical portion 31b. This slit 32 can receive the wire, which is clamped to the metal terminal together with the waterproof seal. In this case, the cylindrical portion serves as a stopper. With this construction, the waterproof seal can be easily pushed without deforming the seal by the distal end of the cylindrical portion 31a, and therefore, advantageously, a waterproof effect can be enhanced. Also, efficiency of the operation can be enhanced as in the above embodiments. (3) In the first embodiment, the tubular portion 14 has the stepped configuration and the cylindrical portion 14b serves as the stopper for limiting the depth of insertion of the tubular portion. However, such a construction as shown in Figs. 6(A) and 6(B) may be adopted. A tubular portion 41, having a uniform diameter throughout its length from its distal end to its proximal end, extends from one end of a grip portion 44, and a projection 42 is formed on a predetermined portion of the tubular portion 41 spaced from the distal end thereof. This projection 42 serves as a stopper. A slit 43 is formed in the tubular portion 41, and extends from the distal end to a position in the vicinity of the projection 42. The slit 43 can receive the wire, which is clamped to the terminal together with the waterproof seal. With this construction, the waterproof seal can be easily pushed without deforming the seal by the distal end of the tubular portion 41. Therefore, advantageously, a waterproof effect can be enhanced. Also, the efficiency of the operation can be enhanced as in the above embodiments. Additionally, the stop 42 can be adjusted so as to change the terminal insertion depth. (4) In the first embodiment, the tubular portion 14 has the stepped configuration and, for example, the cylindrical portion 14b serves as a stopper for limiting the depth of insertion of the tubular portion. However, such a construction as shown in Figs. 7(A) and 7(B) may be adopted. A tubular portion 51, having a uniform diameter throughout its length from its distal end to its proximal end, extends from one end of a grip portion 54, and a pair of projections 52 are formed respectively on opposite sides of the tubular portion 51 at a predetermined position spaced from the distal end thereof. The projections 52 serve as stoppers. A slit 53 is formed in the tubular portion 51, and extends from the distal end thereof to a position in the vicinity of the projections 52. The slit 53 can receive the wire, which is clamped to the terminal along with the waterproof seal. With this construction, the waterproof seal can be easily pushed without deforming the seal by the distal end of the tubular portion 51. Therefore, advantageously, a waterproof effect can be enhanced. Also, the efficiency of the operation can be enhanced as in the above embodiments. (5) In the first embodiment, the tubular portion 14 has the stepped configuration and the cylindrical portion 14b serves as a stopper for limiting the depth of insertion of the tubular portion. However, such a construction as shown in Figs. 8(A) and 8(B) may be adopted. A tubular portion 61, having a uniform diameter throughout its length from its distal end to its proximal end, extends from one end of a grip portion 64, and four projections 62 are formed on a predetermined portion of the tubular portion 61 spaced from the distal end thereof. The four projections are circumferentially spaced at an angle of about 90 degrees from one another. The projections 62 serve as stoppers. A slit 63 is formed in the tubular portion 61, and extends from the distal end thereof to a position in the vicinity of the projections 62. The slit 63 can receive the wire, which is clamped to the terminal together with the waterproof seal. With this construction, the waterproof seal can be easily pushed without deforming the seal by the distal end of the tubular portion 61. Therefore, advantageously, a waterproof effect can be enhanced. Also, the efficiency of the operation can be enhanced as in the above embodiments. (6) In the first embodiment, although the tubular portion has the stepped configuration, the tubular portion is not limited to such a stepped configuration, and the tubular portion may be tapered toward its distal end in a stepless manner, as shown in Figure 9. The invention has been described above with reference to preferred embodiments thereof, which are intended to be illustrative, not limiting. Various other modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims: An insertion tool for inserting a metal terminal (6) within a connector housing (1), comprising: a grip portion (13; 24; 33; 44; 54; 64; 74); and a tubular portion (14; 21; 31; 41; 51; 61; 71) connected to said grip portion (13; 24; 33; 44; 54; 64; 74), said tubular portion (14; 21; 31; 41; 51; 61; 71) including a distal end (100) and having an axial slit (15; 23; 32; 43; 53; 63; 73) therein extending from said distal end (100) in a direction towards said grip portion (13; 24; 33; 44; 54; 64; 74) for housing a wire (9) extending from said metal terminal (6) during insertion of said metal terminal (6) into said connector housing (1), characterised in that said distal end (100) of said tubular portion (14; 21; 31; 41; 51; 61; 71) is engageable with a waterproof seal (12) associated with the metal terminal (6) during insertion of said metal terminal (6) and its associated waterproof seal (12) into said connector housing (1), a stopper portion (14b; 22; 31b; 42; 52; 62; 72) is formed on said tubular portion (14; 21; 31; 41; 51; 61; 71) so that said grip portion (13; 24; 33; 44; 54; 64; 74) is movable towards said connector housing (1) to insert the metal terminal (6) within the connector housing (1) until said stopper portion (14b; 22; 31b; 42; 52; 62; 72) engages an insertion port (7a) of said connector housing (1), and said axial slit (15; 23; 32; 43; 53; 63; 73) ends between said stopper portion (14b; 22; 31b; 42; 52; 62; 72) and said grip portion (13; 24; 33; 44; 54; 64; 74). An insertion tool according to claim 1, wherein said tubular portion (14; 21; 31; 41; 51; 61; 71) comprises at least two stepped portions (14a, 14b, 14c, 14d; 31a, 31b) having different diameters and said slit (15; 23; 32; 43; 53; 63; 73) extends at least along said at least two stepped portions (14a, 14b, 14c, 14d; 31a, 31b). An insertion tool according to claim 1, wherein said tubular portion (14; 21; 31; 41; 51; 61; 71) includes a flange (22) that is adjustably mounted on said tubular portion (14; 21; 31; 41; 51; 61; 71). An insertion tool according to claim 1, further comprising at least one projection (42; 52; 62) formed on said tubular portion (14; 21; 31; 41; 51; 61; 71). An insertion tool according to claim 4, wherein said at least one projection (52; 62) comprises at least two projections (52; 62) formed substantially at opposite diametrical sides of said tubular portion (14; 21; 31; 41; 51; 61; 71). An. insertion tool according to claim 4, wherein said at least one projection (62) comprises at least four projections (62) formed approximately 90° apart on said tubular portion (14; 21; 31; 41; 51; 61; 71).

Inventors: MAKINO HIROTAKA, MAKINO, HIROTAKA, MAKINO, HIROTAKA, C/O SUMITOMO WIRING SYSTEMS, LTD
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1995
Main classification: H01R43
IPC codes: H01R43, H01R13