Patent Publication Number: US-5890916-A

Title: Connector means for connecting a conductor to a ground rail

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Connector means are provided for connecting a conductor, an electrical terminal block or the like with an inverted generally U-shaped ground rail having a pair of upwardly extending legs that terminate in outwardly extending flange portions, including a conductive plate having a body panel that extends transversely above the ground rail and includes at one end a hook portion that is locked beneath the flange portion of a first leg of the ground rail, and at the other end a plate support panel that is bent outwardly from the bottom edge portion of the body panel to a position generally normal to the body panel and in supported engagement with the upper surface a second rail leg. An inverted generally U-shaped spring has a base portion that extends parallel with the body panel above the plate support, and leg portions that are bent inwardly under the support panel and under the flange of the associated leg of the ground rail, respectively, thereby to mount the plate on the ground rail. 
     2. Brief Description of the Prior Art 
     It well known in the patented prior art to provide connector devices for connecting electrical conductors, terminal blocks and the like with a grounded rail conductor. As shown by the German Patent No. DE 39 03 752 C2, and the European Patent No. EP 0 556 560 B1, fastening feet on the connector generate sufficient retaining force for retaining the connector on a mounting rail (such as the ground rail of an electrical panel box) to effect good electrical contact while at the same time affording the necessary mechanical stability. On the basis of these designs, one is no longer dependent on the provision of additional catch feet on the insulated housings of the terminal blocks, but one does require a large volume and therefore extensive resilient force for clamping the connector to the grounded mounting rail. 
     On the other hand, a grounded conductor connection has been disclosed in the European patent No. EP 0 444 656 B1 wherein the contact and the fastening foot are provided with at least one hook segment that grasps one of the mounting rail legs, and where the contact and fastening foot has segments that also sit on the mounting rail legs, the spring being supported to mechanically retain the components together to effect the desired electrical contact force upon the mounting rail legs or on an abutment formed on the contact in the fastening foot. In this case, the resilient spring can no longer engage both mounting rail legs, and therefore the spring can be made relatively short and powerful. Thus, one can basically also select the spring characteristics and size in order to achieve good electrical connection with the conductive mounting rail, which may be formed of copper. However, the known design includes inherent problems, such as providing the connection between the connector in the fastening foot in the spring, which spring contains a slit up to its terminal areas and the contact and fastening foot has perpendicular segments and several abutments such that, for the purpose of final assembly, areas of the contact and fastening foot must be inserted through the slit of the spring on the latter supported against the abutments. The spring thus contacts one mounting rail leg from above when in the position ready for use along with a deformation and generation of the spring force. Making such a spring with a slit is complicated, and the slit also weakens the spring. In this design, the contact and fastening foot has a complicated three-dimensional shape. It is difficult to connect the spring with the contact and fastening foot during assembly. 
     The present invention was developed to avoid the above and other drawbacks of the known connecting devices. 
     SUMMARY OF THE INVENTION 
     Accordingly, a primary object of the present invention is to provide an improved inexpensive ground connector that is formed from conductive plate stock and includes a body panel that extends transversely above and normal to a conventional generally U-shaped ground rail having a pair of upwardly extending legs that terminate in outwardly directed flange portions, said plate body panel having at one end a hook portion that extends downwardly in locking engagement beneath one flange portion of a first leg portion of the ground rail, and a first plate support panel extending normal to the bottom portion of the other end of the body panel in supported engagement with the upper surface of the other leg portion of the ground rail, inverted U-shaped spring means being operable to connect the first support panel with the adjacent rail leg, thereby to mount the connector plate on the ground rail. 
     According to a more specific object of the invention, the first support panel is connected with the body panel by a fold line that is arranged at an acute angle with the horizontal, the spring being connected between the top edge of the first support panel and the associated rail flange. The lower tip portion of the first support panel may be bent downwardly for pointed engagement with the ground rail. A spring mounting panel is connected with the body panel by a generally vertical fold line and extends at right angles to the body panel to a support position in which it supports the base portion of the inverted U-shaped spring. 
     According to a further object, the body panel is provided at the lower portion of its first end with orthogonally bent second plate support panel that engages the upper surface of the first leg of the ground rail. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 is partly sectioned elevation view of the ground connector assembly of the present invention mounted on a ground rail; and 
     FIG. 2 is a plan view of the conductive metal blank from which the conductive plate is formed. 
    
    
     DETAILED DESCRIPTION 
     Referring first more particularly to FIG. 1, the connector means of the present invention includes a conductive plate member P for electrically connecting a pair of conductors C and C&#39; with a grounded mounting rail 4 that is fastened to an electrical panel or the like (not shown). The ground rail 4 includes a generally horizontal base portion 4c and a pair of upwardly extending leg portions 4a and 4b that terminate in outwardly extending flange portions 4a&#39; and 4b&#39;, respectively. 
     Referring to FIG. 2, the connecting plate P is formed from metal stock of a suitable electrically conductive metal material, and includes a generally rectangular body portion 3 having at one end an integral downwardly extending hook portion 5. A first plate support panel 8 is connected with the lower portion of the other end of the body panel 3 by a fold line 14 that is ranged at an acute angle relative to the horizontal, and at the first end, the plate is provided with the second plate support panel 6 that is connected with the lower portion of the panel 3 by fold line 18. At its left hand end, the connector panel 3 is provided with a release panel 7 that is connected with the panel 3 by a fold line 26, and at its right hand end, the plate is provided with a spring support panel 11 that is connected with the panel 3 by a vertical fold line 16. At its top, the plate is provided with a connecting panel 1a by a line of bending 20, the panel 1a having at each end end flaps 1b and 1c that are bent upwardly to the vertical position about lines of bending 22 and 24 when the base panel 1a is bent around fold line 20 to a position normal to the connector plate 3. 
     Assuming that the panels 7, 6, 8, 11, and 1 are bent to positions normal to that of the connector body panel 3, the hook portion 5 is inserted beneath the outwardly extending flange 4a&#39;, and the right hand end of the support panel 8 is seated on the upper surface of the adjacent flange portion 4b reference numeral prime of the grounded U-shaped rail. The mounting spring 10 has an inverted U-shaped construction with a horizontal base portion 10a and a pair of downwardly extending leg portions 10b and 10c of unequal length. The shorter leg portion 10b is hooked beneath the left hand edge of the plate support panel 8, and the intermediate base portion of the spring 10a is seated on the upper surface of the spring support panel 11, as shown in FIG. 1. The longer spring leg 10c extends downwardly and inwardly beneath the outwardly directed flange portion 4b&#39; of the grounded mounting rail 4. 
     Thus, the resilient force of the spring 10 maintains the right hand end portion of the connector body 3 with the upper surface of the rail leg 4b, the other side of the connector body 3 being hooked by hook means 5 beneath the outwardly directed flange 4a of the ground rail 4. 
     The spring clip terminals 2 are connected with the upward extending connecting portions 1b and 1c in a known manner, such that when the movable portions of the terminals are displaced apart, the conductor C and C&#39; can be displaced axially downwardly within corresponding openings contained in the moveable arm portions of the resilient terminals, thereby to effect connection with ground. 
     In order to remove the connecting plate P from the rail 4, a suitable tool (such as a screw driver) is placed beneath the release tab 7 for engagement with the adjacent rail flange 4a&#39;, whereby upward leverage of the tool about the rail flange 4a&#39; produces pivotal lifting of the associated end of the connector means, upwardly relative to the ground rail 4. 
     As indicated above, the fold line 14 for the first plate support panel 8 is arranged at an acute angle relative to the horizontal, whereby the lower edge of the plate member 8 is provided with a sharp tip portion 9 that may be bent downwardly toward engagement with the upper surface of the associated flange portion 4b&#39; as shown in FIG. 1, thereby to improve the electrical contact between the components. It is apparent from the above description that the blank from which the connector is formed can be made in a simple manner by appropriate stamping or cutting together with bending of the associated tabs about their respective lines of bending to positions normal to the plane containing the body panel 3. Good conductivity between the plate and body portion 3 and the ground rail 4 is achieved owing to the inherent spring strength of the spring member 10, and the penetration of the tip 9. 
     Thus, it should be emphasized that according to the basic structural principle of the present invention, spring 10 cooperates with only one mounting rail leg 4, whereby on the structural principal of a bus bar connection, it can be made flexible in a versatile fashion, since when it comes to a configuration of the hook segment area, one is free to adapt to the conditions of the particular mounting rail. For example, if a mounting rail is considerably wider than the one that is shown, even if the configuration of the mounting rail where to deviate at one of its ends, the contact and fastening foot could then be accordingly redesigned in the corresponding area. 
     While in accordance with the provisions of the Patent Statute, 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.