GB607595A - Improvements in or relating to band or hose clips - Google Patents

Abstract

607,595. Band Clips. O'SHEI, W. E. March 15, 1945, Nos. 6468, 7486, 16869 and 34246. [Class 44] The part-threads on the bands of band or hose clips of the kind having a worm or screw engaging the band to tighten it, are produced by a press-like operation by the use of dies which force the material of the band at those parts where the serrations are to be produced in a direction towards one side of a plane through opposite ends of each part thread, and in a direction towards the other side of the plane at the intermediate parts where the teeth are to be produced. The part-threads or serrations 15, Figs. 2 and 4, of a band clip, for example, of the kind described in Specification 602,458, are produced by a pressing, embossing, drawing or like operation between dies or punches 18, 19, Fig. 6, which are preferably of cylindrical form having a series of annular or helical grooves corresponding to the thread to be produced, the grooves of one die being arranged opposite the ridges of the other, producing the form of serration shown in Fig. 5. The dies are preferably of greater diameter than the screw 9 to be used in the clip. Dies with helical grooves are used to produce partthreads of which the helix angle is less than that of the screw, as described in Specification 607,671. To produce bands with a thread of helical angle approximating -to that of the screw while still using large diameter dies, multiple start threads may be used on the dies. To avoid breakage of the dies due to overhang at the end of the thread if the latter is carried to the extreme end of the band, the thread is stopped short of the end, as shown in Fig. 4, and the width of the thread decreases towards the end, or preferably towards each end. The centre line of the threads is preferably offset from the centre line of the band so that the teeth assume a position in alignment with the screw as it is tightened, the clearance of the band in the screw housing allowing slight lateral movement. As shown in Fig. 3, the surface of that part of the clip which underlies the threaded part may be formed or recessed to accommodate the projections thereon, for example, the plain end 3 of the band and the part 2 of the housing may be curved, or spacers may be provided. Alternatively, the projections on the underside of the threaded part may be ground or sheared off, or the material of the projections 16a, Fig. 5, may be forced into the adjoining spaces 17a to make the underside of the band flat. Specification 542,482 also is referred to.