Resilient contact for electrical conductors

[0002] This invention relates to an electrical connector that includes a resilient clamping member having a clamping leg that biases a conductor laterally into electrical engagement with a stationary contact, and a support leg that is operable by a release tool to disengage the clamping leg from the conductor. The clamping leg has a clamping edge adapted to dig into the periphery of the conductor, thereby to resist withdrawal of the conductor from engagement with the contact.

[0003] As evidenced by the German patent No. DE 2802269, it has been proposed in the prior art to provide a resilient electrical contact having a clamping edge that is directed toward the periphery of a conductor, thereby to engage the same to prevent withdrawal of the conductor from the housing within which the contact is mounted. The clamping leg is adapted to be displaced toward a released position relative to the conductor by an operating tool. This arrangement possesses the drawback of the possibility of damage to the conductor by the clamping edge during the withdrawal of the conductor from the contact housing. Furthermore, the clamping member has a rather complicated structure owing to the requirement of a special activation bracket and because, in the front region of the connector chamber, a separate access opening is required through which the activation tool is inserted during movement toward the activation bracket.

[0004] On the other hand, as proposed in the German patent No. 2062158, the free end of the clamping leg may be bent slightly in an attempt to avoid damage to conductor during its withdrawal from the contact housing. This structure has the drawback that the activating portions are provided on the contact leg itself for lateral activation or for activation from above, thereby complicating the contact design but also, in the case of lateral arrangement, makes the provision of multi-row design impossible.

[0005] The present invention was developed to avoid the above and other drawbacks of the known connection art.

[0006] Accordingly, it is a primary object of the present invention to provide a resilient connector that is positively and reliably operable to release the conductor for damage free withdrawal from the contact housing, characterized in that the clamping leg of the clamping member is operable by a release tool toward a released position in which an offset terminal portion of the clamping leg that carries the clamping edge is no longer directed toward the conductor, whereby withdraw of the conductor is unhindered, and damage to the conductor is avoided.

[0007] According to another object of the invention, the release tool is operable to engage the support leg of the resilient clamping member to displace the clamping leg toward the released position relative to the conductor, thereby to avoid damage to, and permanent undesirable deformation of the clamping leg portion of the resilient clamping member.

[0008] A further object of the invention is to provide the clamping leg of the clamping member with an offset terminal portion that carries the clamping edge, whereby when in the disengaged position, the offset portion is parallel with and spaced from the conductor.

[0009] Another object of the invention is to design the portion of the support leg adjacent the juncture between the support and clamping legs for engagement by a release tool having an oblique activating surface, orientation means being provided for assuring that the release tool has the proper orientation about its longitudinal axis relative to the surface of the support leg which it is to engage. Stop means may be provided on the resilient clamping member and/or the housing to limit the extent of angular displacement of the clamping leg relative to the support leg, thereby to avoid overload and permanent undesirable deformation of the clamping member.

[0010] Other objects and advantages of the invention will become apparent from a study of the following specification, when viewed in the light of the accompanying drawings, in which:

[0011] FIGS. 1A-1C illustrate a first embodiment of the invention wherein the clamping spring is in its released, engaged, and fully extended positions, respectively;

[0012] FIGS. 2A and 2B are sectional views of a second embodiment of the invention wherein the clamping spring is in its fully extended and released positions, respectively;

[0013] FIG. 3 is a perspective view of another embodiment of the electrical connector arrangement of the present invention; and

[0014] FIG. 4 is a perspective view illustrating a clamping spring arrangement having a plurality of clamping leg portions and a common integral support portion.

[0015] Referring first more particularly to FIGS. 1A-1C, the electrical connector of the present invention includes a housing 1 that is formed from electrical insulating material and contains a chamber 2 in which is mounted a generally V-shaped resilient clamping member or spring 3 that is operable to bias an electrical conductor 4 laterally into electrical engagement with the bus bar portion 5 of a female electrical contact 6. The resilient clamping spring 3 includes a support leg portion 9 that is supported by a support plate 11 adjacent one wall of the chamber 2, and a clamping leg portion 7 that is biased toward an extended position adjacent the bus bar 5, as shown in FIG. 1C. According to the present invention, the clamping leg portion 7 has at its free end a terminal portion that is connected with the clamping leg portion by a double-bent intermediate portion 15. The terminal portion 15 terminates in a clamping edge 8, said terminal portion being generally parallel with said clamping leg and offset in the direction of said support leg. The housing end wall 1acontains a first opening 12 through which the bare end of the insulated conductor 4 is introduced, whereupon the conductor extends between the clamping leg 7 and the bus bar 5 as shown in FIG. 1B. When the clamping leg 7 is in this engaged position, the clamping edge 8 at the free extremity of the clamping leg is engagement with, and digs into the outer periphery of, the bare end of conductor 4, thereby to resist withdrawal of the conductor from the chamber 2.

[0016] In accordance with a characterizing feature of the invention, the housing end wall 1acontains a second opening 13 opposite the support leg 9 of the clamping spring 3, whereby the operating end of a release tool 14 may be introduced into the housing chamber 2. As best shown in FIG. 1A, the end of the release tool 14 has an oblique end surface 17 that is adapted to engage the support leg 9 and to displace the junction 10 between the support and clamping legs toward the bus bar 5, whereby the clamping spring is deformed toward the released position in which the clamping leg portion 7 is generally parallel with the conductor 4, and the clamping edge 8 is in an offset released position spaced from the conductor 4, whereupon the conductor may be readily withdrawn axially from the chamber 2 and from electrical engagement with the bus bar 5.

[0017] Thus, the double-bent intermediate portion 15 causes the terminal portion 16 of the clamping leg, when in the disengaged position of FIG. 1A, to be offset from, and generally parallel with, the bus bar 5, whereupon the clamping edge 8 is spaced from to the conductor 4.

[0018] In operation, upon progressive insertion of the bare end of insulated conductor 4 into the chamber 2 as shown in FIG. 1C, the end of the conductor engages the clamping leg 7 and displaces the same away from the bus bar 5 toward the engaged position of FIG. 1B, whereupon the clamping leg 7 is angularly arranged relative to the conductor 4, and the clamping edge 8 engages and digs into the outer periphery of the bare end of the conductor, thereby resisting withdrawal of the conductor from the chamber 2. To release the conductor 4 from the bus bar 5, the operating end of the release tool 14 is introduced into the chamber 2 via the second opening 13, whereupon the oblique edge 17 of the release tool engages the surface of the support leg 9 adjacent the support plate 11, thereby to displace juncture 10 toward the bus bar 5, and to deform temporarily the clamping spring 3 to the released position of FIG. 1A. As shown in this figure, the clamping edge portion 7 is thus parallel to the conductor 4, and the offset portion 16 and the clamping edge 8 are parallel with and spaced from the conductor 4, thereby to permit the withdrawal thereof from the housing chamber 2.

[0019] If desired, the housing 1 may be of sectional construction including a pair of housing section 1band 1cthat are either permanently or separately connected.

[0020] It is important to note that the clamping tool 14 engages only the support leg 9 of the clamping spring 3, whereby undesirable permanent deformation of the clamping leg 7 is avoided. As will be described in greater detail below, stop means may be provided for limiting the displacement of the juncture 10 toward the bus bar 5, further to prevent permanent distortion of the clamping spring by the release tool 14. Similarly, the diameter of the second opening 13 corresponds generally with the diameter of the operating end portion of the release tool 14, thereby to assure that release tool 14 may be displaced only longitudinally relative to the housing one, whereby undesirable pivotal movement of the release tool, and the resulting permanent deformation of the clamping spring, are avoided.

[0021] Referring now to the embodiment of FIGS. 2A and 2B, the second housing opening 13bis non-circular and includes an inclined wall surface 13cthe angle of inclination of which corresponds with the operating surface 17bof the operating tool 14b. In this embodiment, the support leg 9acontains a recess 18 defined by a double bent intermediate portion 19, and a an orthogonal end portion 21 that extends within the corresponding recess contained in the housing 1. As shown in FIG. 2, the clamping leg 7 is initially in its fully extended position relative to the bus bar portion 5 of the contact 6. As the conductor 4 is progressively introduced into the housing chamber 2, the clamping leg 7 is progressively displaced toward an engaged position similar to that shown in FIG. 1B, with the clamping edge 8 being partially embedded within the periphery of the bare conductor 4.

[0022] To release the conductor from the housing 1 and the bus bar 5, the release tool 14b—which may be the end of a standard screwdriver—is introduced within the opening 13b, thereby to displace the juncture 10 toward the bus bar 5, and to deform the clamping leg 7 to the released position of FIG. 2A parallel to the bus bar and the conductor 4, thereby causing the terminal portion 16 containing the clamping edge 8 to be spaced from the conductor 4, whereupon the conductor may be axially withdrawn from the chamber 2. It is important to note that in this embodiment, a stationary stop 20 is provided on the housing 1 for limiting the extent of introduction of the release tool 14binto the chamber 2, thereby preventing overload displacement of the support leg 9aand permanent distortion of the clamping leg 7. In this embodiment, the support leg 9aessentially pivots about the end portion 21 at the fulcrum point of its engagement with the housing 1.

[0023] Referring now to FIG. 3, the clamping leg 7 is provided with a stop 19 that cooperates with the support portion 9 to limit the degree of pivotal movement of the support leg 9 around the pivot axis 21 thereby to avoid permanent undesirable deformation of the clamping leg portion 7. In this embodiment, the second opening 13ahas a generally T-shaped configuration, and the working end of the release tool 14ahas a similar T-shaped cross-sectional configuration, thereby to define stop shoulders 14bthat limit the extent to which a release tool 14acan be introduced within the housing chamber 2. This special profiling prevents an erroneous angular insertion of the release tool 14aabout its longitudinal axis, and furthermore prevents any possible pivotal movement of the release tool relative to the housing 1, that otherwise could produce an undesirable permanent deformation of the clamping leg relative to the support leg 9.

[0024] Referring now to FIG. 4, according to a further embodiment of the invention, the clamping spring 3 includes a plurality of clamping legs 3bthat are separated by the slits 24, and which are adjoined by a common support leg portion 3a. In this embodiment, the various clamping legs 3bare each independently operable by a release tool to effect selective withdrawal of the associated conductors 4 from the housing.

[0025] While in accordance with the provisions of the Patent Statutes the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various changes may be made without deviating from the inventive concepts set forth above.