US2425153A - Tube clamp - Google Patents

Description

Aug- 5, 1 4 R. R. HARRISON TUBE CLAMP Original Filed Oct. 10, 1941 6(WELD) INVENTOR ROBERT R. HARRISON A Tram/g r Patented Aug. 5, 1947 TUBE CLAMP Robert R. Harrison, Pacific Palisades, Calif., as-

signor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Original application Oct ober 10, 1941, Serial No. Divided and this application October 4, 1945, Serial No. 620,208

7 Claims.

This invention relates to tube clamps and more particularly to tube clamps which are provided with means to electrically ground any tube or conduit held in the clamp. The present application is a division of my co-pending application Serial No. 414,417, filed October 10, 1941, and entitled Tube clamps. This application has issued as Patent No. 2,399,183, dated April 30, 1946.

One object of the invention is to provide a tube clamp having an electrical grounding strip provided with a curved portion to accommodate vibration well within the elastic. limit of the strip.

Another object of the invention is to provide a tube clamp with an electrical grounding strip which is rigidly aligned with the metal loop forming the main element of the clamp.

Other objects and advantages of the invention will be apparent in the following description and claims taken in connection with the accompanying drawing in which:

Figure 1 is an isometric view of a tube clamp embodying the invention; and

Figure 2 is an isometric View of a portion of the strip of the loop of Figure 1, showing the grounding strip welded to the metal loop, and showing the cushion in dotted outline.

For present purposes, it will be stated that the clamps are used to hold conduits to any structural member of the vehicle in which they are mounted. They are particularly adapted for use in airplanes, and for this purpose a cushion element must be provided to prevent injury to the clamped tube due to the intense vibrations found in airplanes. However, it has been found that static charges accumulate on conduits held in an insulating material such as is commonly employed as the cushion element, and electrical grounding strips are employed to remove the static charges, which present a fire hazard, as well as an interference to radio operation, when they discharge across an air gap.

The clamp of Fig. 1 comprises a metal strip 40 of aluminum, or where great strength is required, of stainless steel, although it may be made of any suitable electrically conductive material. The metal strip 49 is bent to a rounded shape so as to form a loop to encircle any tube or conduit which may be held therein. One end 41 of the strip 48 is bent at right angles to the body of the strip, so as to be parallel with the other end and permit a screw to be passed through holes 49 and 53 in the ends 4'! and 5! to secure the clamp as a whole to any member. The clamp is provided with a cushion 42, which is preferably of a resilient material such as the commonly available synthetic rubber-like materials. which are resistant to oil and gasoline. Since such cushions are usually insulators, a grounding strip 44 is secured to the metal loop 49 and overlies the cushion 42 so as to electrically ground any conduit to the metal of the clamp loop 40.

The loop strips 49 are first formed in a fiat position (Fig. 2). The grounding strip 44 is welded to the loop strip 40 by a spot weld 46, after which the cushion 42 is bonded to the strips 40 and 44 by methods well known to the art. The outer end of the strip 44 is then bent upwardly and over to overlie a portion of cushion 42 as shown in Fig. 1. Thereafter the metal strip 40 is bent to the shape shown in Fig. 1.

The construction described has the advantage over prior art structures that the long bend in the grounding strip 44 at the region 48 which is in excess of gives a suflicient are or curvature in the strip 44 so as to accommodate any reversals of stress without bending the strip in the region 48 beyond the elastic limit of the material. This insures freedom from fatigue cracks in the grounding strip 44 and insures that the grounding strip will always overlie the cushion 42. The reversals of stress in the grounding strip 44 may be caused by vibration in service between the clamp and the tube or conduit supported thereby.

Reversals of stress are further reduced or eliminated in accordance with the invention by the fact that the cushion. is vulcanized or bonded to the clamp strip 40.

As has been previously mentioned, the of the grounding strip 44 to the strip 40 that it will not swivel about its point of ment and thereby work out of contact conduit engaged by the clamp.

Although the invention has been explained by showing and describing in detail a specific embodiment thereof, various changes from the specific construction shown will be apparent to those skilled in the art, and the invention is therefore to be limited only to the extent set forth in the appended claims.

I claim:

1. In a line grounding clip embodying a metallic supporting strap, and a cushioned seat carried by said strap and extending along the inner periphery thereof; an electrically conductive strip bent intermediate its ends and positioned astride an end of said cushioned seat with one of its end portions extending between said seat and said strap and with its other end portion overlying the outer face of said seat for interposition between said seat and a conduit imposed on the welding insures attachwith any latter to effect electrical connection between said conduit and said strap around the terminus of said cushioned seat.

2. A tube clamp comprising a loop of metal, a cushion element overlying a portion of the inner face thereof, and an electrical conductor secured to the loop and overlying a portion of the-cushion, said conductor being formed with a pronounced curved portion with at least a 170 curve therein to accommodate stresses.

3. In a line grounding clip embodying a metallic supporting strap and a cushioned seat carried by said strap and extending along the inner periphery thereof; an electrically conductive strip bent intermediate its ends and positioned astride an end of said cushioned seat with one of its end portions extending between said seat and said strap and with its other end portion overlying the outer face of said seat for interposition between said seat and a conduit imposed on the latter to effect electrical connection between said conduit and said strap around the terminus of said cushioned seat, and means effecting a positive connection between said electrically conductive strip and said supporting strap.

4. The structure called for in claim 3 in which the connection between the strip and strap is located beneath an end portion of the cushioned seat to be covered by the latter.

5. In a line grounding clip, a metallic line supporting strap, a cushioned seat lining said strap, an electrically conductive strip having a portion overlying said cushioned seat and disposed to contact a conduit seated on said seat and having another portion overlying an end of said cushion seat and extending between the latter and said strap, whereby said portions of said strip will be pressed into said cushion on clamping said strap around a conduit, with a positive connection between one of the named portions of said strip and said supporting strap.

6. A tube clamp comprising a loop of metal, a conductor strip having a portion welded to said metal loop, and a cushion overlying a portion of said conductor strip and a portion of said metal loop, said conducting strip being bent back upon itself to overlie a portion of said cushion.

'7. Atube clamp comprising a loop of metal, a conductor strip having a portion welded to said metal loop, and a cushion overlying the portion of said conductor strip welded to said metal loop and also overlying a portion of said metal loop, said conducting strip being bent back upon itself to overlie a portion of said cushion.

ROBERT R. HARRISON.

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