GB2260656A - Electric connector having press-fit contacts - Google Patents

Abstract

A connector body (20) has a plurality of contacts (18) each mounted in a hole (24) by means of barbs (38). Barbs (38) of adjacent contacts (18) are offset along the length of the contacts. <IMAGE>

Description

ELECTRIC CONNECTOR HAVING PRESS-FIT CONTACTS The present invention relates to a connector providing an electrical connection, and more particularly, to a connector having a plurality of contacts press-fitted into an insulator within a casing.

For connecting a connector with an electric wire, a connector in which the electric wires are first terminated to contacts and then the contacts are pressfitted into an insulator arranged within a casing of the connector to provide the connection is known. In this kind of connector, the insulator made of electrically insulating material has a plurality of holes for receiving the contacts. Within each of the holes, there may be provided a retaining member such as a clip for retaining the contacts, or alternatively an engaging portion to be engaged with a shoulder of the contact without using such a retaining member. Otherwise, engaging projections may be formed on the contact and forced to bite into the wall of the hole for the engagement, by the elasticity of the insulator without any provision within the holes.With further miniaturization and a higher integration of electronic components, it is required to increase the number of contacts and narrow the pitch thereof. Accordingly, in order to cope with the increased number of holes in the insulator for engaging and retaining the contacts, the method in which the engaging projections of the contacts are caused to bite into the wall of the hole with the aid of the elasticity of the insulator is advantageous.

Figures 5a and 5b show a principal part of a conventional connector using such a method. In this connector, a plurality of contacts 4 each having engaging projections 3 that engage with an inner wall of each of the holes 2 of an insulator 1 are of substantially the same shape, and hence the engaging projections 3 are formed at substantially the same position in a lengthwise direction of the contacts 4.

The above-described method in which the engaging projections of the contacts are allowed to bite into the walls of the insulator is advantageous to the connector, which is small in size and includes a multiplicity of contacts, since there is no need for any particular locking structure within the holes. However, as this method utilizes elastic deformation of the insulator, further thinning of the wall of the insulator arising from the reduction in the pitch of the contacts may bring about damage due to the deformation of the wall of the hole.That is, the above method involves the drawback that the wall of the hole between the adjacent contacts is simultaneously compressed from two directions when inserting the contacts into the holes since he engaging projections of the contacts are formed at substantially the same positions in a lengthwise direction, which often causes damage such as cracking due to the deformation of the wall of the hole beyond the elastic limit, thus leading to instability in the engagement of the contacts.

The present invention is designed to solve the above problems, of which the object is to provide a connector with contacts adapted so as to be press-fit to the insulator, and capable of preventing damage to the insulator when press-fitting the contacts.

In order to achieve the above objects, the present invention provides an electric connector having press-fit contacts, comprising a casing, an insulator contained within said casing and made from an elastically deformable and electrically insulating material, a plurality of holes provided in said insulator, and a plurality of contacts each inserted into said holes, respectively, by a pressing force and disposed in said casing so as to be insulated from one another; characterized in that said contacts have means for engaging the contacts within said holes provided with said insulator in such a manner that said means elastically deforms an inner wall of the holes and is engaged with the wall, and that said means are arranged at different positions along a length of said contacts in each of the contacts adjacent to one another.

According to the preferred embodiment of the present invention, the invention also provides an electric connector in which said means for engaging the contacts within said holes comprises engaging projections protruding from side faces of each of said contacts, and said projection are alternately arranged at different positions along a length of said contacts in all of the contacts.

When a plurality of contacts are press-fitted into their respective holes of the insulator, the engaging means of the contacts is engaged with inner wall of the hole while pressing against the wall surface for elastic deformation thereof. At that time, engaging means are each arranged at different positions in a longitudinal direction in each of the adjacent contacts, and hence the wall is not pressed simultaneously from two directions by the engaging means at any position. In other words, since the wall of the hole is not compressed between the engaging means of the adjacent contacts, the possibility of deformation of the insulator beyond the elastic limit can be eliminated, which leads to the prevention of damage to the insulator.

The present invention will be more completely described with reference to the accompanying drawings, wherein like numbers refer to like parts in the several views, and wherein: Figures la, lb and lc are a plan view, a front view, and a side view, respectively, of the connector embodying the present invention.

Figure 2 is a sectional view taken along a line 2-2 of Figure la.

Figures 3a and 3b both a and b are both explanatory drawings of the assembly of the connector shown in Figures la through lc; Figure 3a is a partial sectional view showing separately the connector body and the chain member of the contact; Figure 3b is a side view of the chain member of the contact.

Figures 4a and 4b are partial sectional views of the connector in Figures la through lc, with Figure 4a being an enlarged sectional view of the portion shown in circle IV of Figure 4a.

Figures Sa and 5b are partial sectional views of a conventional connector; with Figure 5b being an enlarged sectional view of the portion shown in circle V of Figure 5a.

Hereinafter, the present invention will be further detailed based on an embodiment thereof with reference to the accompanying drawings. The following description will be of an example in which the present invention is applied to a connector for connecting a printed circuit board.

Referring to Figures la, lb and lc, shown is a connector 10 for connecting a printed circuit board in accordance with the present invention, viewed from three different angles. The connector 10 comprises a base 12 in contact with the surface of the printed circuit board, a connector body 16 having a fitting portion 14 that extends over the base 12 to fit into the associated connector, and a plurality of contacts 18 arranged within the connector body 16 at predetermined intervals to one another. As shown in Figure 2, the base 12 and fitting portion 14 of the connector body 16 include a casing 20 integrally formed therewith, and an insulator 22a and 22b made of electrically insulating resin material accommodated inside the casing 20. As clearly shown in Figures 3a through 4b, the insulator is composed of a rear insulator portion 22a located at the base 12 and a front insulator portion 22b located at the fitting portion 14. The rear insulator portion 22a has a plurality of retaining holes 24 for retaining one of the contacts 18, while the front insulator portion 22b has a plurality of grooves that allow the deformation of the contacts 18 upon connecting the connector.

The contacts 18 are separated and formed from a chain member 28 integrally molded by pressing as shown in Figure 3b, and are made of electrically conductive spring steels. The chain member 28 is molded in such a manner that the plurality of contacts 18 extend from a continuously extending carrier 30 toward one side and substantially parallel to one another. Each of the contacts 18 has at its top a sliding contact piece 32 in contact with the associated contact (not shown), and a reduced diameter portion 34 between the sliding contact piece 32 and the carrier 30. The plurality of contacts 18 are press-fitted to the base 12 of the connector body 16 as described later, and cut off at the reduced diameter portion 34 to separate the same individually.

The contacts 18 are bent at two different position in the vicinity of the reduced diameter portion 34 as shown in Figure 3b, and the adjacent contacts 18 extend to two mutually parallel planes, to thereby form legs 36 extending parallel along the two planes (Refer to Figure 2). The legs 36 of the contacts 18 pass through the printed circuit board for connection with the printed circuit.

As shown in Figure 3a, each of the plurality of contacts 18 has at the root of its sliding contact pieces 32 engaging projections 38 that are engaged with the rear insulator portion 22a of the base 12 of the connector body 16. The engaging projections 38 are symmetrically formed on both sides of each of the contacts 18 so as to protrude like teeth of a saw and have a shouldered tapered surface 38a, and engage the rear insulator portion 22a at the top of the tooth or shoulder 38b of the tapered surface 38a. In relation to the adjacent contacts 18, the shoulders 38b of the engaging projections 38 are formed at locations separated from each other by a predetermined distance in a longitudinal direction. In general, the shoulders 38b are formed with a displacement of a predetermined distance relative to those of adjacent contacts 18.

When thus configured contacts 18 are attached to the connector body 16, the contacts 18 as the chain member 28 are press-fitted into the plurality of retaining holes 24 provided at the rear insulator portion 22a of the base 12 of the connector body 16 from the backside or bottom side of the connector. At that time, the sliding contact piece 32 of each of the contacts is advanced along the retaining holes 24 of the rear insulator portion 22a and the groove 26 of the front insulator portion 22b, and arranged in the connector body 16 at a predetermined position while maintaining a mutually parallel relation. Simultaneously, the engaging projections 38 of each of the contacts 18 advance so that the retaining hole 24 of the rear insulator portion 22a is forcibly spread out by the tapered surface 38a.At the completion of this press-fitting process, the shoulder 38b is allowed to engage with the wall surface of the retaining hole 24 with the aid of the elastic deformation of the rear insulator portion 22a, thereby preventing the contacts 18 from being dislodged. In this way, the contacts 18 are fixed within the insulator 22 of the connector body 16 in a mutually insulated manner. In the present invention described above, the engaging projections 38 of the contacts 18 have shoulders 38b separated from one another by a predetermined distance in a longitudinal direction thereof, and accordingly the tapered surfaces 38a of the engaging projections 38 of the adjacent contacts 18 are not permitted to simultaneously spread out the retaining hole 24 of the rear insulator portion 22a.Consequently, the wall of the retaining hole 24 intervening between the adjacent contacts 18 are not simultaneously pressed at both sides, but pressed in an alternating fashion, whereby the pressing force can be released by a wave-like deformation, thus leading to an effective prevention of the occurrence of the damage such as cracking.

As is apparent from the above description, the present invention is structured so that the engaging means for engaging the contacts within the holes of the insulator while elastically deforming the walls of the holes, is provided on each of the contact to be pressfitted into the holes of the insulator at different position in a longitudinal direction relative to those of the adjacent contacts, whereby the wall surface of the hole is not simultaneously pressed from two directions by the engaging means at any position when press-fitting the contractors. The wall of the hole is not compressed between the engaging means of the adjacent contacts, to thereby prevent deformation beyond the elastic limit of the insulator and provide a connector with a press-fit type contact free from damage of the insulator such as cracking.

Claims (3)

Claims:

1. An electric connector comprising a casing, an insulator contained within said casing and made from an elastically deformable and electrically insulating material, a plurality of walls in said insulator defining holes, and a plurality of contacts inserted one into each of said holes and disposed in said casing so as to be insulated from one another; wherein said contacts have means for engaging said holes in such a manner that said means elastically deforms said wall defining said holes and is engaged with the wall, and wherein said means for engaging said holes are arranged at different positions along the length of said contact for each adjacent contact.

2. An electric connector according to claim 1 wherein said contacts have two major surfaces and side edges connecting said major surfaces and wherein said means for engaging said holes comprises engaging projections protruding from said side edges of each of said contacts, with said projections of adjacent contacts being alternately arranged at different positions along the length of said contacts.

3. An electric connector according to claim 1 substantially as herein described with reference to the accompanying drawings.