SE428982B - ELECTRICAL CONTACT DEVICE - Google Patents

Description

7805193-5 miniature circuits. Due to the behavior of the pressure forces just mentioned, the contact must consist of metal and be made relatively coarse. The object of the invention is to provide a contact device in which the individual contacts resp. the contact means are also able to absorb the forces generated by the insertion of the wires, but can still be made thinner. This shall also apply to the maximum transverse dimensions of the members, which in turn entails a corresponding reduction in the dimensions of the cover. Thirdly, the contact means can thus be placed closer to each other.

In very short terms, the inventive idea can be said to lie in the realization that each contact member can be provided with a loop-shaped part, which is arranged so that when inserting a wire the wire-receiving part of the contact will be subjected to drawing instead of pressure.

This eliminates the need for lateral projections in the contact members.

U.S. Pat. No. 3,955,873 discloses a contact device which in some respects resembles the known contact described above but in which each contact member has only a single lateral projection which cooperates with a shoulder on the wall of the cavity. Even with this known contact, however, the wire-receiving part is subjected to pressure stresses and the single projection would probably not be able to absorb the forces generated by mechanical connection of wires to the contacts. In each case, it can be stated that even this single projection increases the transverse dimension of the contact member and thereby reduces the number of members that can fit within a housing with given dimensions.

Incidentally, it should be noted that in this known device the forces which occur when inserting the wires are low, due to the fact that the insertion takes place obliquely and gradually by means of a lid on the cover rather than by means of tools. In addition, the contact means are relatively complicated.

Another similar contact device is disclosed in U.S. Patent 3,992,072. In this case, although there is no protrusion, the base of the wire receiving member abuts the shoulder of the cavity, but this means that the contact member will be subjected to compressive forces, so the designer's freedom of design of this part is greatly pruned.

The characterizing features of the invention appear from the appended claims and a pair of embodiments thereof are described below with reference to the drawing.

Pig. 1 shows in perspective view a device according to a first embodiment. .

Fig. 2 shows an exploded perspective view of parts of the contact device.

Fig. 3 shows a longitudinal section through the device.

Fig. 4 corresponds to Fig. 3 but shows the interaction with a contact pin.

Fig. 5 shows in plan view a part of the wire receiving surface of the housing.

Fig. 6 shows in plan view a part of an adjacent surface of the housing, partly in section for illustrating the design of the cavity.

Fig. 7 shows a section through a device according to a second embodiment of the invention.

Fig. 8 shows in perspective view a holding band for contact devices according to the first embodiment.

Fig. 9 shows in perspective view a contact member, intended to be inserted into a cavity of a cover according to Figs. 1-8.

Fig. 10 shows the contact of Fig. 9 seen from above.

Fig. 10A shows the contact of Fig. 10 seen from one end.

* FIG. 11 shows in section a side view of a part of the device according to Figs. 1-8 with a contact member according to Fig. 9 in a cavity within the housing.

Fig. 12 shows the device according to Fig. 11 seen from above, wherein a contact member according to Figs. 1-4 is located in another of the cavities.

Fig. 13 shows in perspective view a device according to Figs. 1-6 provided with a lid of modified design.

The contact device 2 in Fig. 1 is intended for individual connection of insulated wires 4 to contact pins 6, which project from an insulating disc 8 through holes in a plate 10 on its upper side. The contact pins 6 can be soldered to wires (not shown) on the underside of the disc 8 or connected in another way.

The following description sections refer to Figs. 2-6.

The contact 2 has a cover 12 consisting of insulating material, which encloses a plurality of electrical contact means 14. The cover suitably consists of nylon or of some other plastic material, which allows its production by injection molding. The housing has a wire-receiving boundary surface 16, an opposite surface 18, side walls 20, 22 and end walls 24, 26. Between the surfaces 16 and 18 extend a number of continuous cavities 28, each of which consists of three sections, namely a wire receiving part 30, a transition part 32 and a part 34 for receiving a contact member. The section 30 is slightly wider than the section 34 and has inner walls 38, 38 '(Fig. 5), which extend across the side walls 20, 22. Since these end walls are mutually similar, only one of them will be described here. The inner side walls 40, 42 of the section 30 are located close to and parallel to the side walls 7805193-5 20 respectively. 22, but they are different from each other. The end wall 38 is substantially planar but has a central flange 44 which extends from the lower part of the section 34 towards the surface 16. The flange tapers in this direction and has at its upper end 46 - as shown in Figs. 2, 3 and 4 - a shoulder 48, which is parallel to the surface 16 and located at a distance therefrom further into the housing 12. As will be clarified below, the shoulder 48 and the side surfaces 47 of the flange 44 have the function of supporting and positioning a contact member 14 inside the housing 12 when a wire 4 is pushed into the socket. The lower part 50 of the flange 44 is wider than its upper part and passes via a shoulder 52 into one end wall 57 of the section 34. Above the shoulder 52 a groove 43 is formed by one side surface 47 of the flange 44 and by the side wall 42 - see Fig. 2.

In each end wall 38, 38 'there is a further groove 54 adjacent the lower part 50 of the flange 44 and the side wall 56 of the section 34. This groove 54 extends up to the wall 74 of the cavity 28. Opposite the wall 56 is a wall 58 of the section 34 , so that a groove with a triangular profile is formed (Figs. 5 and 6). The walls 56 and 58 merge within the section 32 into the walls 40 and 42.

The section 32 is delimited by a flat surface 60 facing the mouth of the section 30 adjacent the side wall 40 and a surface 62 which extends to the wall 56. On the wall 42 there is also a shoulder 64 and a sliding surface 66, which later merges into the wall. 42, see Fig. 3.

The wall 22 has an opening 72 for receiving a wire 4, which is to be connected to the contact means 14 in the manner indicated below. the lower limiting surface 71 of the opening 72 is flush with the shoulder 60.

On the side wall 22 there are outer flanges or strips 76, which at their upper ends have barbed-like members 78, the free end portions 82 of which form a kind of lock which allows a wire 4 to be pressed into a contact 14 in the associated cavity 28 but makes extraction impossible. of the thread. The means 78 also relieves the wire from attempts to pull it out of the connector 14.

An opening 68 in the wall 20 communicates with the section 34 for receiving a locking tab 106 of the contact 14, which prevents the contact from being pulled out of the cavity 28 after it has been inserted therein. A square opening 36 for receiving a contact pin 6 extends through the side surface 18 and the wall 74.

Each contact means 14 consists of an elongate strip of sheet metal, which is folded into a loop shape, so that two opposite contact arms 100 and 102 are formed, intended to receive a contact pin between them. These arms merge at the top into two portions 88 and 90, which form the wire receiving part 84 of the contact means and which at the top are connected to each other via U-shaped bridges 92, 7805193-5 between which the wire is pressed into and for connection to the contact.

The portions 88 and 90 each have a slot 94 for receiving the wire, which boundary walls of the slots merge into ramps 96, which increase the lateral distance between the bridges 92, so that the insertion of the trees is facilitated. The designation 98 refers to U-shaped embossments with the task of having a reinforcing effect.

The contact arm 100 extending downwardly from the plate 88 carries the above-mentioned tab 106, intended to cooperate with the opening 68. The arm 100 has a free end surface 114. The second plate-like portion 90 normally extends slightly obliquely relative to the plane of the plate 88 and passes via shoulders 104 in the narrower contact arm 102.

The arm 102 is bent at 108 so as to form an elongate contact spring 109, which converges in the direction of the arm 100. Its free end portion 110, on the other hand, diverges and has triangularly bevelled end surfaces 112, intended to be received in the above-mentioned groove in the wall 58.

According to Fig. 2, the arm 102 is in its rest position relative to the arm 100. When the contact means is to be inserted into the housing 12 by means of the guide surfaces 80 on the walls 38, 38 ', the arm 102 is first bent inwards towards the arm 100, whereupon the contact means is pressed down from its position in Fig. 2 to the fully inserted position of Fig. 3. The side edges of the arm 100 are received in the grooves 54 and the end portion 110 of the arm 102 is guided between the ramp surfaces 66 along the side walls 42 into the triangular groove in the wall 58. When the contact is fully inserted in the cavity 28, the arm 102 is kept biased and in abutment with the arm 100 by the bent part at 108 then abutting against the wall 58.

The insertion movement of the contact member is limited by the bridges 92 coming into abutment against the shoulders 48 at the upper ends of the strips 44. The side surfaces 47 thereby position the contact means laterally.

The flap 106, which bends inwardly during the insertion movement of the contact member, finally snaps into the opening 68, thereby retaining the contact member in the cavity 28. In the fully inserted position of the contact 14, its side edges are in the grooves 43 and 54 in the end walls 38, 38 '.

As shown in Fig. 3, the free end surface 114 of the arm 100 is located at a distance from the wall 74 of the cavity 28 when the contact is fully inserted. The same is so dimensioned in relation to the cavity 28, that this effect is achieved, i.e. the surface 114 does not abut against the wall 74. This relative dimensioning is also chosen so that the shoulders 104 of the contact 14 are located slightly above the shoulders 52 of the housing 12 and so that the shoulders 48 of the strips 44 touch the undersides of the bridges 92.

The wires 4 are connected to the contact means 14 by placing each wire in front of the opening 97 between the bridges 92, after which the wire is pressed down and guided by the ramps 96, until it has been fully inserted into the slots 94. This insertion of the wire exposes the contact means to a considerable mechanical load, which gives rise to high stresses in the material. Since this consists of thin sheet metal, for example with a thickness of approx. 0.3 mm, such stresses can damage the contact if they are not kept under control and, if the stresses are transferred to the pin receiving part of the contact, this can also be damaged. According to the invention, however, it is achieved that these downward forces can only produce isolated stresses in the wire receiving part and that these stresses are completely limited to the area between the bridges 92 and to the parts of the plates 88 and 90 which are located between the wire and the bridges. During the insertion movement, a wire will exert a downward force against each of the plates 88 and 90, but since the bridges 92 are supported by the shoulders 48, these forces will be counteracted by upward reaction forces in the bridges 92, so that only the upper part of the contact member is loaded. The pin receiving part will therefore not be affected at all by the high stresses that develop in the upper part of the contact.

From the above it should also appear that the wire receiving part is subjected to drawing instead of pressure.

The stresses which arise in the wire receiving part are not of the same kind as those which provide galvanic contact between the wire core and the opposite edges of the slots 94 as they penetrate the insulation of the trees. When the wire is inserted into the slots 94, portions of the plates 88 and 90 bend outwardly on either side of the slots, since the wire is oversized relative to the slot width. It is these forces that create and maintain the galvanic contact.

Corresponding stresses in the material remain after the wire "has come to rest in the slots and they must be maintained so that the contact pressure is not lost. Although the stresses generated when the wire is inserted into the contact are only temporary and disappear when the insertion process is completed, they are nevertheless sufficient to be able to damage the contact and it is to avoid such damage that the shoulders 48 are arranged.

As mentioned above, the end surface 114 of the arm 100 is spaced from the wall 74 of the cavity 28 and the shoulders 104 are spaced from the shoulders 52. The shoulders 48 will therefore absorb all the insertion forces.

If, on the other hand, the end surface 114 of the arm 100 were to abut against the surface 74 (which it does not do), then the bridges 92 would be at a distance from the shoulders 48 and the arm 100 would be subjected to buckling stresses upon insertion of the trees 7805193-5.

After the wires are inserted, they protrude to the side through the openings 72 and abut against the trailing edges 82 of the barbs 78, so that they are retained in the openings 72.

The contact device can be miniaturized, with particular reference to the side dimensions of the cover. This is achieved thanks to the fact that each contact member 14 is shaped like a loop and the total dimensions of the wire receiving part insignificantly exceed the corresponding dimensions of the pin receiving part, as shown in Figs. 2, 3 and 4. This simple design of the contact member makes it possible to hang up the same on the shoulders 48 and thereby thereby in the manner described above protect the same from harmful stresses.

FIG. 3 and 4 show that the contact arm 102, which serves as the movable contact spring leg, has a large lever length in relation to the total length of the contact member, i.e. the distance between the bridges 92 and the free ends of the arms 100, 102. This is very advantageous, since the contact pressure generated between the arm 102 and an inserted contact pin 6 can be accurately controlled by appropriate choice of the metal wall thickness, degree of hardening and the extent to which the arm 102 is biased.

Thanks to the simple shape and simple suspension of the contact member 14, the contact device has a low manufacturing cost.

While according to the embodiment illustrated in Figs. 1-6, the ends of the wires 4 abut against, or are close to, the inner side wall 40, as best seen in Fig. 1, the embodiment according to Fig. 7 is intended for connection to a section of the wire at a distance from its free end. The main difference between the two embodiments is that according to Fig. 7 an opening 114 is provided at each cavity in the side wall 20a (corresponding to the wall 20) and that barbed means 116 for stress relief, similar to the means 78, are located between the cavities. Furthermore, the wall 20a is provided with reinforcing strips 118, which support the members 166. A contact device according to Fig. 7 can be used, for example, in cases where it is desired to connect wires to two or more groups of contact pins.

Fig. 8 shows how a plurality of contact devices made according to Figs. 1-6 can be fastened to a carrier strip 120, for example by gluing. The band abuts the lower part of the wall 20. The arrangement constitutes a convenient form for storage and delivery of the contacts. These can then be connected to wires by means of a machine which has means for feeding the belt into it, so that each contact in turn is positioned correctly in front of the tools which cut the wire and insert it. Such a machine is described, for example, in US 7805193-5 4 043 034. The following part of the description refers to Figs. 9-12. Contact means 122, intended to by so-called contact pressing connected to insulated wires 144, can advantageously be produced in the form of a long strip with a support strip 124, from which the individual contacts project laterally. Each such contact comprises a substantially U-shaped sleeve 126, which via a neck portion 128 connects to the strip 124. The sleeve 126 extends transversely in relation to the longitudinal direction of the strip. Via an L-shaped portion 130, the sleeve part 126 merges into the pin receiving part, which is located along the strip 124.

This part comprises contact arms 138 and 140, corresponding to the arms 100 and 102 of the contact 14. The arm 138 has a punched locking tab 142.

The substantially parallel arm portions 132 and 134 have projections 136 which project below the portion 138 as shown in Fig. 10A. These parts 132, 134 have approximately the same width as the plates 88 and 90 in the contact 14, so that the contact can be inserted into a cavity 28 of a housing 12 according to Fig. 12.

When the device is to be fitted with wires, each contact sleeve 126 is pressed at 126 'around the stripped end of a wire 144 by means of a contact pressing tool (not shown), which simultaneously separates the contact blank from the strip 124. Thereafter, the contact and wire are inserted into the cavity 28. tab 142 snapped into the opening 68. The movement is limited by the free end of the arm 138 reaching the bottom of the abutment cavity. As shown in Figs. 11 and 12, the pressed sleeve 136 'is located in the wire receiving section 30 of the cavity, while the side edges and projections 136 of the parts 132 and 134 are received in the grooves 43 and 43, respectively. 54. The arm 140 is biased by abutment against the wall 58 in the same manner as the arm 102 of the contact 14.

The situations in which it may be desired to insert into a housing 12 both a number of contacts 122 and a number of contacts 14 are, for example, when one or more of the wires is too coarse to be used with the contacts 14 or when it is desired to provide a common ground. connection for shielded wires. Such a ground connection can then be obtained by bending the shield socks of the conductors away from the conductors and pressing them together in a contact 122. The wire cores of the conductors are then connected to contacts 14 in the manner indicated above.

As shown in Fig. 13, the housing of the device can be provided with a lid 146 of a synthetic plastic material, which lid excludes moisture and dirt from the cavities 28 and in addition further relieves stress on the wires. The lid 146 has a flat upper part 147 with downwardly directed side walls 148, 150, the lower edges 152, 154 of which are folded inwards, so that they can be snapped over the corresponding corners 156 of the housing. However, the lid can also be held by the snap action together with the barbs 82 - see Fig. 2.

Claims (8)

7805193-5 1Û Patentkrav 1. An electrical contact device with an insulating housing, enclosing at least one cavity for receiving an electrical contact means, which has a wire receiving part adjacent one end of the cavity, to which a wire can be connected under the action of one against the other end of the cavity. directional force, and a contact member extending from the wire receiving member toward the opposite end of the cavity, the wire receiving member abutting shoulders opposite the inner walls of the cavity to prevent displacement of the contact member toward the other end of the cavity. under the influence of said force, characterized in that the wire-receiving part (84) of the contact is designed as a loop, the curved portion of which is divided into two bridges (92), which define a mouth (97) between them, leading to wire receiving slits (94) in the legs or arms (100, 102) of the loop, the inside of each bridge (92) abutting one of the shoulders, which project between the arms (100, 102), through these are subjected to tensile stresses when a wire is inserted into the slots (94). Contact device according to claim 1, characterized in that on each of the opposite inner walls (38) of the cavity (28) there is a strip (44), which extends in the longitudinal direction of the arms (100, 102) and ends close to one end of the cavity to form one of the shoulders (48), these two strips (44) being arranged to determine the position of the contact member (14) in the cavity (28). _ Contact device according to claim 2, characterized in that one of the arms (102) next to the bent portion of the loop has a plate-like part (90), which in the direction of its free end merges into a narrower contact spring arm (109) and whose side edges rest in grooves (43) defined by the strips (44) and by the adjacent side walls (42) of the cavity (28), the contact spring arm (109) at (108) abutting against another inner wall (58) of the cavity, so that they * are the same biased in the direction of the second arm (100), the side edges of which rest in grooves (54) in walls (38) of the cavity (28). 7805193-5 11 Contact device according to claim 3, characterized in that said second inner wall (58) of the cavity (28) forms a triangular depression in cross section, which from the other end of the cavity (28) extends towards its first-mentioned end, the contact spring arm (m9 ) has a free end portion (110) which diverges from the second arm (100) and whose end surface (112) is adapted to be received in the recess. Contact device according to claim 1, 2, 3 or 4, characterized in that the cavity (28) has at its one end (16) a further section (30) for receiving the bridges (92) of the contact member (14). , a wall (22) of this wire receiving section (30) having an opening (72) which allows the insertion of a wire into the mouth (97) perpendicular to the longitudinal direction of the trees, and the wall (22) has an outer strip (76). ) with a resilient projection (78), which limits the free area of the opening (72) in order to hold a wire (4) inserted through the opening. IN Contact device according to claim 5, characterized in that the opposite wall (20a) of the wire receiving section of the cavity has a wire receiving opening (114), located opposite the first-mentioned opening (72) and arranged to allow an inserted wire extending through the wall (20a) having an additional outer strip (118) with a protrusion (116) for retaining the wire in the opening (114). Contact device according to claim 3 or 4, characterized in that at least one of the cavities (28) is arranged to receive a contact member (122) with a sleeve (126), which is clamped on a wire by contact pressing ( 144), which is located in the further section (30) of the cavity (28). Contact device according to one of the preceding claims, characterized in that one end surface of the housing is covered by a resilient cover (146), consisting of a disc (147) and of side walls (148, 150) with inwardly bent edge portions (102 , 154) for holding by snap action with corresponding surfaces (156) of the housing.