Jumper connector

Abstract: A jumper connector (15) for connecting contact pins or posts (14) protruding from a pin header (12) mounted on a printed circuit board (11) has an accessible conductive core (16) made of a conductive elastomer. As shown, two apertures (17) extend through the conductive core (16) so as tightly to fit on the pins or posts (14) that are to be electrically connected one to another. An insulating mantle (18) covers the accessible core (16), such that the connector (15) is rendered simple in structure, can be produced inexpensively, can be used with a high density arrangement of pins or posts (14), with the electric resistance of the core selected to be at a desired level. Instead of the pins or posts (14) contact may be made with contact portions of the printed circuit board (11).

Description: The invention relates to a jumper connector electrically to connect to one another two contacts or terminals on a printed circuit board. Figure 10 of the accompanying drawings shows a typical example of prior art jumper connectors 4 in use with a pin header 2. The pin header mounted on a printed circuit board 1 has an array of contact pins or posts 3. Each jumper connector 4 electrically connects any one of those pins to a neighbouring one of the pins and comprises two sockets 6 fittable on those pins 3 and united together by a conductive piece 7 to form a socket contact 5 secured in an insulating housing 8. Thus, two of the pins 3 will communicate with each other by means of such a socket contact 5. The prior art jumper connectors 4 are however somewhat disadvantageous in that their socket contacts 5 are complicated in structure and expensive to manufacture. They also occupy a considerably large space on a circuit board, thereby failing to match a high density arrangement of contact pins or posts. US Patent No. 4,516,817 discloses a jumper comprising a rigid outer shell within which a sculptured metal pin-engagin part is provided. The outer shell is closable by a push-fit plug. According to one aspect of the invention there is provided a jumper connector for electrically connecting contact pins or posts protruding from a printed circuit board, or for electrically connecting patterned conductive portions formed on a printed circuit board, the jumper connector being characterised by: an accessible connector core of conductive elastomer; at least one inner contact surface formed in or on the accessible core, the contact surface being capable of being brought into contact with the pins, posts or patterned portions; and an insulating mantle secured to and covering an outer surface of the accessible core. Such a jumper connector can be simple in structure, inexpensive and suitable for use with high density arrays of contact pins while allowing the resistance of its conductive core to be selected as desired. Thus the conductive elastomer forming the accessible core contains an amount of a conductive filler dispersed in an elastomeric matrix. The amount is selected to meet an electric resistance of a level required for the core. The filler is preferably carbon black or a powder of conductive and stable metal such as copper, nickel and silver. Embodiments of the invention are diagrammatically illustrated by way of example in the accompanying drawings, in which:- Figure 1 is a front elevation of a jumper connector shown in use according to a first embodiment of the invention; Figure 2 is a plan view of the jumper connector of Figure 1 in use; Figure 3 is a perspective view of the jumper connector of Figure 1; Figure 4 is a plan view of a jumper connector according to a second embodiment of the invention; Figure 5 is a cross section taken on line 5-5 in Figure 4; Figure 6 is a perspective view of the jumper connector shown in Figure 4; Figure 7 is a plan view of a jumper connector according to a third embodiment of the invention; Figure 8 is a cross section taken on line 8-8 in Figure 7; Figure 9 is a perspective view of the jumper connector shown in Figure 7; and Figure 10 is a perspective view of a prior art jumper connector shown in use. Some embodiments of the invention will now be described referring to the drawings. In an embodiment illustrated in Figures 1 to 3, a jumper connector 15 is designed for use with a pin header 12. The pin header is mounted on a printed circuit board 11, and has a base housing 13 penetrated by a plurality of upright contact pins or posts 14. The jumper connector 15 comprises an accessible core 16 that is a short column elliptic in cross section and made of a conductive elastomer. A pair of apertures 17 are formed through the core 16 to open at opposite ends thereof. Two of the contact pins or posts 14 will be fitted in the apertures 17 for making a "jumper connection". An insulating mantle 18 made of a nonconductive elastomer covers a whole outer periphery of the accessible core 16. In manufacture, materials forming the core 16 and the mantle 18 may for example be extruded simultaneously through a common duplex. A composite elongate rod thus produced will subsequently be severed into lengths. In each length, i.e., the jumper connector, the core 16 is integrally bonded to the mantle 18. The conductive elastomer forming the core 16 is preferably a silicone rubber having an amount of carbon black dispersed therein. Carbon black as the conductive filler may be replaced with a powder of any conductive metal such as copper, nickel or silver. The amount of such a filler can be voluntarily selected to meet a required resistance of the accessible core 16. From a viewpoint of affinity between the materials, the insulating mantle 18 is preferably made of a certain nonconductive elastomer, as noted above. This elastomer may be the same or a different silicone rubber that is free of conductive filler but miscible with the core material. It is also possible to use as the mantle a hard cover formed of Nylon (a registered trademark) or a similar insulating plastics. The jumper connector 15 will be used in a manner as seen in Figures 1 and 2. The apertures 17 in the accessible core 16 fit on two neighbouring ones of the pins or posts 14. Due to elasticity of the core 16, those pins electrically connected therethrough will be held in tight contact with inner peripheral surfaces of the respective apertures 17. A "jumper connection" thus made between the pins 14 will have a predetermined electric resistance. This resistance inherent in the core 16 is freely chosen by varying the amount of conductive filler such as carbon black dispersed in the elastomer, as noted above. A jumper connector 22 in a second embodiment shown in Figures 4 to 6 is designed for use with a printed circuit board 11 whose patterned conductive portions 21 are to be jumper connected. This connector 22 comprises an accessible core 23 made of a conductive elastomer but is U-shaped in cross section in this case. Therefore, this U-shaped core 23 can grip with its elastic force the circuit board 11. Similarly, an insulating mantle 24 integral with and covering an outer surface of said conductive core 23 is of a U shape. The conductive elastomer forming the accessible core 23 in this case is also preferably composed of a silicone rubber and a conductive filler dispersed therein. The filler is carbon black or a metal powder such as copper, nickel or silver. The amount of filler may be selected to give the core a predetermined resistance. The insulating mantle 24 is preferably made of a nonconductive elastomer free of conductive filler but having affinity to the core material. It is also possible to use as the mantle a hard cover formed of Nylon or like insulating plastics. The printed pattern may comprise, in addition to the conductive portions or leads 21 formed on an upper surface of the circuit board 11 as shown in Figure 4, further conductive portions 21 (see Figure 5) on a lower surface, corresponding to those on the upper surface. The jumper connector 22 will be used in a manner as seen in Figures 4 and 5. The accessible core 23 having arms 23a and 23a facing one another will elastically grip therebetween the printed circuit board 11. The arms 23a are pressed against the conductive portions 21 and 21 electrically to connect them to each other, thus providing between them a "jumper connection" of a predetermined electric resistance. Similarly to the first embodiment, the resistance of the core 23 can be freely selected by varying the amount of conductive filler such as carbon black dispersed in the elastomer. In a case wherein the insulating cover 24 is made of a silicone rubber or like elastomer, its elastic force will be exerted on the facing arms 23a of the core 23 so that they can more surely contact the patterned portions 21. A jumper connector 22 in a third embodiment shown in Figures 7 to 9 is also designed for use with a printed circuit. This connector is similar to that in the second embodiment except that its accessible core 25 is not U-shaped but planar. Similar reference numerals are allotted to similar parts and description thereof is not repeated. The core 25 in this case is also made of a conductive elastomer. The insulating cover 24 has arms 24a and 24b facing one another, and the core 25 is secured to an inner face of only one of those arms 24a. The other arm 24b cooperates with the core 25 elastically to grip the circuit board 11. The pressing of the accessible core 25 onto the patterned portions 21 and 21 will be made more effective, if the insulating cover 24 is made of an elastic material and its elastic force is added to the elasticity of the core 25. In summary, the jumper connector provided herein has a core part made of a conductive elastomer and having two peripheral inner surfaces, or alternatively one or two planar inner surfaces, to be brought into contact with the pins, posts or patterned portions. Since the core part merely need be covered with a nonconductive mantle, the present connector is so simple in structure as to be manufactured at a lower cost. Moreover, this jumper connector is particularly adapted for high density arrays of contact pins or posts. Since any designer of the connector of the invention can freely select the amount of a filler dispersed in the conductive elastomer, it is easy for him or her to adjust to any desired level the electric resistance of jumper connection made between the pins, posts or between the patterned portions.

Claims: A jumper connector (15;22) for electrically connecting contact pins or posts (14) protruding from a printed circuit board (11), or for electrically connecting patterned conductive portions (21) formed on a printed circuit board (11), the jumper connector (15;22) being characterised by: an accessible connector core (16;23,25) of conductive elastomer; at least one inner contact surface formed in or on the accessible core (16;23,25), the contact surface being capable of being brought into contact with the pins, posts or patterned portions; and an insulating mantle (18;24) secured to and covering an outer surface of the accessible core (16;23,25). A jumper connector according to claim 1, wherein the conductive elastomer forming the accessible core (16;23,25) comprises an amount of conductive filler dispersed in an elastomeric matrix, such amount being chosen to provide a desired level of electrical resistance to the core (16;23,25). A jumper connector according to Claim 2, wherein the filler is either carbon black or a conductive metal powder. A jumper connector according to Claim 3, wherein the metal powder is copper, nickel or silver. A jumper connector according to any of Claims 1 to 4, wherein the insulating mantle (18,24) is formed of non-conductive elastomer. A jumper connector (15) according to any preceding claim, comprising: two apertures (17) extending through the conductive core (16) to provide a pair of inner contact surfaces each capable of being brought into contact with a respective pin or post (14) protruding from the printed circuit board (11). A jumper connector (22) according to any of Claims 1 to 5, wherein: said accessible conductive core (23) is U-shaped and has arms (23a) facing one another, the arms (23a) being capable of elastically engaging the circuit board (11) and patterned conductive portions (21) formed thereon; and wherein said insulating mantle (24) is secured to and covers the accessible core (23) and is also U-shaped, the mantle urging the conductive core (23) towards the portions (21) of the conductive pattern. A jumper connector (22) according to any of Claims 1 to 5, wherein: said insulating mantle (24) is U-shaped and has two arms (24a) facing one another, said accessible conductive core (25) being planar and being secured to one of the arms (24a), the core (25) arms elastically engaging the printed circuit board (11) to urge the conductive core into contact with the conductive pattern formed on the printed circuit board.

Inventors: HASEGAWA MIKI, HASEGAWA, MIKI
Applicants: JAPAN SOLDERLESS TERMINAL MFG, JAPAN SOLDERLESS TERMINAL MFG CO LTD
Application year: 1996
Main classification: H01R9
IPC codes: H01R11, H05K1, H05K3, H01R4, H01R31, H01R12