Method for forming a cutting contact element

Abstract: A contact element having a cutting section for insulation displacement connection of an insulated electrical conductor. The contact element being folded from a flat sheet of electrical conducting material, having a generally rectangular part which bears a lip projecting from one of its sides provided with a cutting slit in the end face and an angular piece having a part connected to said rectangular part and extending essentially parallel to said lip, and having a part which is at right angles thereto and faces away from said lip. The last mentioned part being provided with a further cutting slit in the end face. By appropriate folding of said flat sheet, a contact element being provided having a cutting section for side-piercing of an electrical conductor

Description: The invention relates to a method for forming a cutting contact element which has two lips substantially opposite each other and spaced apart, having formed therein slits of which the edges are at least partially designed in such a way that they can cut through the insulation of a conductor pressed into said slits until they come into contact with the conducting core thereof, and a fastening part connected to said lips, comprising the steps of forming a flat sheet which has a generally rectangular part which bears a lip projecting from one of its sides, which has one of said cutting slits, and a piece which has the other one of said cutting slits; folding the rectangular part to a rectangular channel along two first fold lines extending substantially parallel to each other in spaced apart relation so that one of the sides of said channel is extended by the projecting lip and the bottom of said channel comprises said piece having the other one of the cutting slits; folding said piece inwards towards the channel along a second fold line which extends perpendicular to the first fold lines; and folding the extending lip with the slit formed therein inwards towards the channel through a right angle along a third fold line which extends parallel to the second fold line. Such a method is known from EP-A-0082697. In the known method the flat sheet is formed and folded such that the one lip having formed therein a slit is disposed inside the rectangular channel formed by folding said sheet along said two first fold lines, and the other slotted lip forms a cover which is folded over the corresponding open end of said channel. By this arrangement of the slits with respect to said channel the access to the slits is hampered in pressing said conductor into said slits. The object of the invention is to provide a method of the type mentioned herein above by which an improved cutting contact element is obtained. This object is achieved through the fact that in the method accoring to the invention said one slit is formed in the terminal end face of said projecting lip and said piece is an angular piece which has a part which is connected to the rectangular part of the flat sheet and extends essentially parallel to and in the same direction as the projecting lip, and a part which is at right angles thereto and faces away from said lip and which terminates in the other one of said cutting slits so that the bottom of said channel is extended by the angular piece, which piece is folded inwards along the second fold line in such a way that the part with the slit rests on the projecting lip extending the side of the channel, while the end portion of said extending lip is folded inwards along said third fold line. An essentially rectangular recess extending from the side lying opposite the above mentioned side of the rectangular part of the flat sheet is formed in said part, essentially in the center, so that lip-shaped parts situated on either side thereof are formed, and after folding of the flat sheet to a rectangular channel the sides of said channel are extended by said lip-shaped parts, which in the end form a clamp-type fastening part of the contact element made up of two resilient lips which extend on either side of a plane which is disposed perpendicular to the plane extending through said slits. The contact element obtained by the known method is also provided with a clamp-type fastening part made up of two resilient lips, but these lips extend on either side of the same plane extending through said slits. This arrangement of the resilient lips with respect to the slits makes the known contact element difficult in installing it. The invention is explained in greater detail with reference to the drawing, in which: Fig. 1 shows a flat sheet from which the contact element according to the invention is folded; and Fig. 2 shows the contact element in perspective. As shown in Fig. 1, the flat sheet has a generally rectangular part 1, in which a generally rectangular recess 2 is provided from one side, so that two lip-type parts 3 and 4 are formed. In the opposite side of the rectangular part 1 a projecting lip 5 is present, with a slit 6 disposed in the end face thereof. This side of the rectangular part 1 also has formed in it an angular piece 7, with a part 7′ connected to the rectangular part 1, and a part 7″ standing at right angles thereto, in which the second slit 8 is disposed. The rectangular part 1 also contains a recess 9 which is in the form of two slits 9′ spaced apart and running parallel to each other, and a triangular part 9″ situated between them. As shown in Fig. 2, the flat sheet is bent along the fold lines a and b to form a rectangular channel, the parts of the rectangular part 1 situated on either side of the triangular part 9″ of the recess 9 forming raised, generally trapezoidal projections 1′, which are used for fastening the contact element in a housing, which is not shown. The angular piece 7 is also folded inwards along the fold line c, so that the part 7″ with the slit 8 formed therein comes to rest on the projecting lip 5. Finally, the end part of the projecting lip 5 is folded inwards round the fold line d, which means that the slits 6 and 8 come to rest opposite each other. Reference number 10 shows a conductor which is pressed into the slits 6 and 8, the edges of these slits having cut through the insulation of the conductor until they come into contact with the guiding core. Fig. 2 thus shows clearly that the conductor 10 extends in the lengthwise direction of the contact element.

Claims: A method for forming a cutting contact element which has two lips substantially opposite each other and spaced apart, and having formed therein slits (6,8) of which the edges are at least partially designed in such a way that they can cut through the insulation of a conductor pressed into said slits until they come into contact with the conducting core thereof, and a fastening part connected to said lips, comprising the steps of forming a flat sheet which has a generally rectangular part (1) which bears a lip (5) projecting from one of its sides, which has one (6) of said cutting slits, and a piece (7) which has the other one (8) of said cutting slits; folding the rectangular part to a rectangular channel along two first fold lines (a, b) extending substantially parallel to each other in spaced apart relation so that one of the sides of said channel is extended by the projecting lip (5) and the bottom of said channel comprises said piece (7) having the other one of the cutting slits (8); folding said piece (7) inwards towards the channel along a second fold line (c) which extends perpendicular to the first fold lines (a, b); and folding the extending lip (5) with the slit (6) formed therein inwards towards the channel through a right angle along a third fold line (d) which extends parallel to the second fold line (c), characterized in that said one slit (6) is formed in the terminal end face of said projecting lip (5) and said piece (7) is an angular piece which has a part (7′) which is connnected to the rectangular part (1) of the flat sheet and extends essentially parallel to and in the same direction as the projection lip (5), and a part (7″) which is at right angles thereto and faces away from said lip (5), and which terminates in the other one (8) of said cutting slits so that the bottom of said channel is extended by the angular piece (7) which piece is folded inwards towards the channel along the second fold line (c) in such a way that the part (7″) with the slip (8) rest on the projecting lip (5) extending the side of the channel, while the end portion of said extending lip (5) is folded inwards towards the channel along said third fold line (d). The method according to claim 1, characterized in that an essentially rectangular recess (2) extending from the side lying opposite the above-mentioned side of the rectangular part (1) of the flat sheet, is formed in said part essentially in the center, so that lip-shaped parts (3,4) situated on either side of the rectangular recess (2) are formed, and after folding of the flat sheet to a rectangular channel the sides of said channel are extended by said lip-shaped parts (3,4). The method according to claim 1 or 2, characterized in that a recess (9) is formed in the center of said rectangular part (1), said recess being formed by two slots (9′) spaced apart and parallel to each other and joined by a triangular recess (9″) so that when the flat sheet is folded along the two first fold lines (a,b), opposite side portions (1′) of the triangular recess (9″) are raised upwards to form parallel trapezoidal projections.

Inventors: VAN WOENSEL JOHANNES MARIA BLA, VAN ZANTEN ALBERTUS, VAN WOENSEL, JOHANNES MARIA BLASIUS, VAN ZANTEN, ALBERTUS
Applicants: CONNECTOR SYSTEMS TECH NV, DU PONT NEDERLAND, CONNECTOR SYSTEMS TECHNOLOGY N.V., DU PONT DE NEMOURS (NEDERLAND) B.V.
Application year: 1990
Main classification: H01R4
IPC codes: H01R4, H01R13