GB1196655A - Improvements in and relating to Fasteners - Google Patents

Abstract

1,196,655. Releasable fastenings. MINNESOTA MINING & MFG. CO. 6 July, 1967 [7 July, 1966], No. 31135/67. Heading B2S. A fastener comprises a pair of interengageable articles each having a base from which project a multiplicity of spine-like elements, each comprising an enlarged head at the end of a resiliently flexible stem, the heads or ordered groups of the heads being unordered, so that when the articles are interengaged a majority of the element heads of each article are held beneath the element heads of the other article over the area of engagement. The term 'unordered' refers to the relative positions of the element heads or groups of heads and means a lack of mathematical predictability thereof. It can result from a lack of order in the positions of the elements of their heads or of the orientation of assymmetrical element heads; in other words, their positions can not be predicted. The unorder can appear in only one or in more than one of the co-ordinates used to describe locations of the heads or the groups of heads. Thus, for example, using the rectangular co-ordinate system to describe the positions of the element heads, two of the co-ordinates may be arranged in a predictable relationship but the third co-ordinate unordered and hence the location of any element head would be unmathematically unpredictable. In certain methods of manufacturing the articles the pattern of 'unorder' of the element heads or groups of heads can repeat itself on the article, for example, when the latter is made in the form of a continuous web. The heads can be spherical or bullet shaped or can be formed by distorting the stem so that the head is at an angle to the stem. As shown in Figs. 1 and 2 the element heads are unordered in the length and width dimensions of the base but are all at the same height, the heads in this case being spherical although they could be bullet shaped. As shown in Fig. 7 the heads are at different heights and are of different dimensions the stems also varying in dimensions; the stems can be ordered in the length and width dimensions of the base when the heads are at different heights in which case the unorder of the heads is in one dimension. but alternatively the stems are unordered in the length and width dimensions of the base and the heads are unordered in the height dimension so that the heads are unordered in three dimensions. A construction using unordered groups is shown in Fig. 4 each group consisting of three elements. Fig. 6 shows a construction in which the element heads are off-centre with respect to the stems and the elements shown are made from the rods shown in Fig. 5 by melting the end portions of the rods. The fasteners can be made of thermoplastic or thermosetting polymers, numerous examples being given or of metal or fibrous products such as paper, resin bonding fibre sheeting and laminated sheets. One method of manufacture described is to flock rods without heads onto the base sheet and fix them there by having the base sheet in a molten condition at the time of flocking or by using a strong permanent adhesive. The volume of each rod is made so that it is equal to the volume of the headed element to be made from it and using vibratory flocking techniques the rods are oriented substantially perpendicular to the base in the unordered positions; the rods are then formed with heads by heating so that the head end portion of each rod melts to form the head. The melting can be carried out by an infra red source, jets of hot air, or bypassing the article with the unheaded elements under a heated object such as a metal bar. An alternative method of manufacture is to form each article with unheaded rods by using a die roll which carries an unordered pattern of holes for the formation of the unheaded rods and the heads are then formed by melting as previously described. It is also stated that the articles can be made by injection moulding, compression moulding, progressive stamping and die forming, casting, investment moulding, embossing and vacuum forming. The pair of articles comprising the fastener can be made non-releasable by securing them together with an adhesive.