Hooks
United States Patent Clinch Apr. 29, 1975 HOOKS 1.339.986 5/1920 Schmidt 24/2305 CR 1.494.289 5/1924 R \und H 24/2305 CR [75] lnvemo&#34; W 1.531.295 3/1925 King 24/2305 CR England 1702.946 2/1929 Powers et al 1. 24/2305 TP [73] Assigneel ITW Limited, Slough 3.829.935 8/1974 Critchfield 24/90 B Buckinghamshire. England Primary ExuminerD0nald A. Griffin [22] Flled&#39; 1974 Anorney. Agem. or FirnzR0bert W. Beart; .l. R. [21] Appl. No: 457,514 Halvorsen [30] Foreign Application Priority Data [57] ABSTRACT May I], 1973 United Kingdom 1. 22640/73 I A one-piece molded plastic upholstery button for re- 52 0.3. Ci. 24/2305 TP; 5/356 Ceiving a p 0f Cord is disclosfid- The button has a 51 Int. Cl A44b 1/18 Shank with a terminal portion which extends back [58] Field ofSearch 24/2305 R 24/2305 CR ward the head 9 the bulfion and which has a mngue 24/230 p 4/ 0 90 B; 5/356 on it that is closely spaced to a stop member to form an entrance gap to a cord receiving channel. A protu- [56] References Cited berance adjacent the bottom of the channel serves to i i i th b I! UNITED STATES TS lock the cord in p ace .1 e 0 cm of the channel 21 [.408 l/l879 Kampf 24/2306 TP UX 2 Claims 3 Drawing Figures I[[ 18 2/. 111 I 12 I HOOKS This invention concerns hooks, and in particular hooks which are formed on members which have to fasten to loops of cord. Cord is to be understood as meaning any material which can withstand tension but not compression in the direction of its length.  
  Loops can become released from hooks if the cord becomes slack. The problems occurs, for example, in furniture upholstery. Upholstery buttons lie over apertures in opposite sides of cushions and are connected to one another by cords passing through the cushions. The tension in the cord, when the cushion is not sat on, holds the stuffing of the cushion in place. The most convenient arrangement for assembly is to use a loop of cord, and give each button a hook.  
  Unfortunately sitting on the cushion relaxes the tension on the loop, and permits it to become disarranged in the hook, whereupon the subsequent removal of a person from the cushion can release the loop from the hook. While it is known to give hooks fastenings to trap cords therein, that is not convenient when the hooks have to be one-piece plastics mouldings for economy of manufacture.  
  According to this invention, a hook is a onepiece plastics moulding and has, in order, a head, a shank which has a body extending axially from the head then a terminal portion which extends back from the free end of the body towards the head, the radially inner part of the terminal portion extending as a tongue towards the head, and there being a stop projecting from the head, lying radially outwards of the tongue, and being spaced therefrom by a narrow gap.  
  One hook constructed in accordance with this invention is described below with reference to the accompanying drawing, in which:  
 FIG. 1 is a front elevation;  
 FIG. 2 is a side elevation; and  
  FIG. 3 is a section taken as indicated by the arrows lll-lll seen in FIG. 1.  
  The hook is a one piece plastics moulding and has a head 10, the shape and purpose of which are irrelevant to the present invention. Extending from the head is a shank, the body 12 of which extends axially. The free end of the body curves smoothly to blend into a terminal portion 14 of the shank which extends back towards the head. The bight portion of the hook is smoothly curved, its profile as viewed in elevation in FIG. I being two semi-circular arcs. The outer arc of the bight has its centre of curvature on the axis of the head, which coincides with a side of the shank, whereas the inner arc terminates on that axis. The bight therefore diminishes in thickness from the body to the terminal portion. The radially inner part of the terminal portion 14 extends as a tongue 20 towards the head. The tongue 20 is radially offset from the terminal portion towards the shank. Projecting from the head is a stop 22 which lies radially outwards of the tongue 20 and is spaced from the tongue 20 by a narrow gap 23. By &#34;narrow is meant that the width of the gap is substantially less than the thickness of the cord with which the hook is intended to be used, as described more fully below.  
  The radially outer surface 16 of the terminal shank portion 14 terminates at a shoulder 18 which faces generally towards the head. More precisely, the surface 18 of the shoulder faces obliquely towards the head in a radially outward direction. The surface of the shoulder blends smoothly into the radially outer surface of the tongue 20.  
  The space lying between the shank on the one side, and the terminal portion of the shank with the tongue on the other, has a protuberance projecting into it from the shank body. The protuberance defines a further narrow gap between itself and the tongue, being of the same order of width as the gap 23. The protuberance has the effect of making the space 24 axially convergent/divergent.  
  In use the hook is used with a loop of twisted Terylene&#34; (RTM) cord which is usually, but not necessarily, twisted yarn, spun from a large number of fine monofilaments. The diameter of the yarn is substantially equal to the width of the space 24, which is about two or three times larger than the width of the gap 23.  
  The loop is anchored on one side of a cushion, for example by one of the hooks described passing into an aperture in that face of the cushion, and the loop is pulled through the cushion by a hooked instrument. With the loop in tension, the free end of the loop is forced through the gap 23, requiring the loop to be forced axially towards the head. The tongue and terminal part of the hook can flex radially inwards because of the diminishing thickness of the hook in the terminal portion. The loop can then pass axially down the space 24 and manual tension forces it past the protuberance 26. Release of the tool holding the loop then causes the cushion to expand and hold the loop in tension, securely pulling against the bight portion of the hook.  
  If someone sits on the cushion the button becomes pressed towards the loop, probably twisted and made to lie askew. It has been found with all upholstery buttons that a side of the loop tends to form a secondary loop which rests around the hook. When the person sitting subsequently removes himself, the tension in the loop, although sufficient to force the side of that secondary loop through the narrow gap into the space 24, in fact acts in the direction away from the head, which in the hook of the present invention is also away from the opening of the gap 23. The secondary loop therefore slides from the hook. The fact that the tension in the cord moves the secondary loop away from the gap 23 arises from the fact that the stop 22 lies radially outwards of the tongue; the loop has to pass axially towards the head in order to be able to pass into the space 24.  
  As a secondary feature the smooth oblique shape of the shoulder 18 discourages the side of the secondary loop from becoming lodged, because when the sitter removes himself from the cushion the shoulder causes the side of the secondary loop to slip off restoring the stable safe condition of the loop in the bight.  
  The hook shown can be moulded in a two-plate mould. A suitable material from which to mould the hook is nylon.  
 I claim:  
  1. A molded plastic upholstery button for receiving a loop of a cord comprising a head, a shank having a body which extends axially from said head and which has a terminal portion that extends back toward said head from a bight segment of said shank with said terminal portion beginning at said bight segment, a tongue formed on the end of said terminal portion which extends toward said head in said axial direction, a stop positioned outwardly of said tongue and extending from said head in said first direction to a point adjacent at a point adjacent said end of said channel to form a locking gap of a width which is less than the thickness of said cord so that said cord may thereby be secured into place at said end of said channel.  
  2. A molded plastic upholstery button as claimed in claim I wherein said tongue has an obliquely sloping, outwardly facing shoulder and reduced thickness as said tongue approaches said entrance gap.