US 3114953 A
Description (OCR text may contain errors)
Dec. 24, 1963 G. DOELTER CONTINUOUS FASTENERS 2 Sheets-Sheet 1 Filed Aug. 51, 1961 2 lcf WOW Dec. 24, 1963 s. DOELTER commuous FASTENERS 2 Sheets-Sheet 2 Filed Aug. 31, 1961 United States Patent 3,114,953 CONTINUOUS FASTENERS Gandolph Doeiter, 96 Beaufort Mansions, Beaufort St, London- SW. 3, England Filed Aug. 31, 1961, Ser. No. 135,166 Claims priority, application Great Britain Jan. 17 1961 5 Claims. (Cl. 24205.1)
The invention relates to continuous fasteners of the kind employed to join together edge portions of two tapes or sheets of flexible material (e.g. textile fabric) and which comprises for each tape or sheet, a row of fastener elements along the edge portion to be joined, each element having a shank by which the element is secured to the flexible material and an enlarged head at one end of the shank, the heads of each row of elements fitting between the shanks of the elements of the other row when the joint is closed and engaging behind the heads of said other row of elements to prevent separation of the sheets or tapes in the general plane thereof and also, for each tape or sheet, a row of outer elements which, in substance, are of U-shape and hold between their arms a fold of the flexible material around the other ends of the shanks of the fastener elements of that tape or sheet, there being, usually, one outer element for each fastener element. Fasteners of this kind are described, for example, in British patent specifications Nos. 723,998, 769,535, 769,536 and 769,537.
According to the invention a fastener of the kind described is characterised by ties or pins extending between the opposed arms of at least some of the outer elements.
The ties or pins may pass through holes in the arms and be secured to the arms by riveting or by expansion into the holes whereby separation of the arms is resisted.
It is preferred that the ties or pins pass through holes in the shanks of the fastener elements with the advantage that they can serve to hold the fastener elements in place. It then becomes possible to construct the fastener elements of flat form.
It has been found to be desirable to use rivets of tubular form of which the ends are expanded into the holes in the arms of the outer elements, the mouths of the holes preferably being countersunk.
The above described features are especially suited to fasteners having elements of relatively large size.
The outer elements in fasteners of the kind described usually serve two functions. One is to secure or assist in securing the flexible material to the shanks of the fastener elements. The other is to assist in obtaining a fluidtight seal at the joint. In the known fastener construction they do that in this way. Each of the two pieces of flexible material is, as already stated, folded around the ends of the shanks of the fastener elements of the appropriate row and the fold is held within the arms of the U- shaped outer elements. Where the flexible material leaves the outer elements at each face of the joint, it is turned against the ends of the arms of the outer members. These ends of the two rows are in opposed relation and the two pieces of flexible material are held in surface to surface contact where they lie against these ends.
At one face of the joint it is usually only the extreme edge portions of the flexible materials which are held in this way and, in any case, any material which projects beyond the outer members is free. For ease of reference this face will hereinafter be called the outer face of the joint Without implying any limitation as to which face is to be inside or outside of say a package or wrapping, in use. At the other face of the joint the flexible materials continue away from the joint as the main bodies of the two sheets or tapes to be joined. This face will hereinafter be called the inner face.
In practice the surfaces aforesaid of the two pieces of 3,114,953 Patented Dec. 24, 1963 flexible material may be held in light pressure contact due to the interengagement of the fastener elements and this will provide a fluid seal along the joint. If a fluid pressure is applied to either face of the main bodies of the flexible material there is caused a tension or so-called hoop stress in the material which tends to pull apart the two rows of fastener elements this tension being resisted by the interengagement of the fastener elements. The tension is however applied at the inner face of the joint at a position offset from the line of engagement of the fastener elements and accordingly there is caused a bending or twisting moment about the line of engagement. One effect of this is to tend to increase the pressure between the surfaces of the flexible material at the outer face of the jointthereby increasing the fluid tightnessand to separate the surfaces of the flexible material at the inner face of the joint. If, as is usually desirable for other purposes, the flexible material has substantial compressibility, this may result in substantial flexing of the joint about the said line of engagement which may cause bending or even breaking of the fastener elements or possibly disengagement thereof. It is an object of the immediately following and preferred features of the invention to provide an improved construction in which such flexing is reduced.
Such an improved construction is as above defined and further characterised in that at the outer face of the joint the flexible sheets or tapes are not carried over the ends of the arms of the outer elements but, when the joint is closed, the edge portions of the two sheets or tapes are brought into sealing contact along a line between the fastener elements and the adjacent arms of the outer elements and, at this face of the joint, the arms of the outer elements are extended so that they are in contact or, preferably, nearly in contact, when the joint is closed.
With the construction just described any bending or twisting moment as aforesaid is positively resisted by the direct engagement of the ends of the opposed arms of the outer elements on the outer face after little, or no, flexing of the joint. When, as is preferred, the arms are initially nearly in contact, a limited amount of flexing is permitted before the arms come into engagement. This causes increased sealing pressure engagement between the said edge portions of the sheets or tapes. It is further preferred that these portions are closely embraced and supported by the fastener elements and the arms of the outer elements so that they offer considerable resistance to deformation and substantial sealing pressure between the portions can be developed.
Another preferred feature is that each flexible sheet or tape is doubled on itself and the fold provides the sealing surface.
A specific construction of a fastener according to the invention will now be described, by way of example, with reference to the accompanying drawings in which:
FIGURE 1 is a cross-section through the two parts to be joined, the planes of the sections through the two parts being displaced in the direction perpendicular to the paper, for simplicity,
FIGURE 2 is a section through the closed fastener without application of hoop stress,
FIGURE 3 is a view corresponding to FIGURE 2 but showing the effect of hoop stress, and
FIGURE 4 is a diagrammatic under plan view of part of the closed fastener.
Each part to be joined comprises a sheet 10 of flexible material such as rubber impregnated fabric. This sheet is doubled on itself along the fold line 11, in the form shown in FIG. 1. The doubling of the sheet provides strength coupled with flexibility and avoids any form of raw edge at 11.
Within the fold of each sheet there is a row of fastener elements 12 each formed of flat material and having a shank 13 of rectangular section with an arrow head 14, the shape of the head being known (e.g. from the specifications above-mentioned). Around each fastener element and embracing the fold in the sheet there is an outer element 15 of U-form. In plan view, the free ends of the arms of the outer elements are wider than the base, the width gradually tapering from the arms to the base. The outer elements are each secured to their associated fastener element by a tubular rivet 16 of which the ends are expanded into the mouths of the holes in the outer elements without endwise compression of the rivet.
The arm 18 of each outer element is longer than the arm 19 and of such a length that when the fastener is closed (FIGURE 2), the opposed ends of the two arms 18 are separated by only a slight distance. It will be ap preciated that the opposed elements are in staggered relation but nevertheless overlap in opposition. The length of the arms 19 is such that when closed they compress only slightly the fabric as it passes around the ends of these arms and as seen at 20.
The inner faces of the arms 18 are chamfered at 21 and they are arranged to trap the folded edges 11 against the fastener elements, the folds extending a little beyond the ends of the arms 18 as seen in FIGURE 1. Accordingly and as seen in FIGURE 2 at 22, the edges 11 are compressed together under substantial sealing pressure in the closed fastener.
In the construction as described and shown, the arms 18 are at the outer face of the joint as above defined and the arms 19 are at the inner face.
If fluid pressure is applied perpendicular to the main bodies 24, 25 of the fabric, in either sense, the result is to produce a hoop stress in the fabric in the direction of the arrows (FIGURE 3) tending to separate the fastener. The effect of this is to produce a moment about the line (approximately at 26) of connection between the fastener elements which, in turn, tends to separate the opposed arms 19 and, as the folds 11 compress, to close the ends of the arms 18 together. This flexing of the joint is however limited by the fact that the ends of the arms 18 quickly come into direct contact and so firmly resist further flexing.
1. A sliding clasp fastener having: (a) two pieces of sheet-like flexible material to be joined together along edge portions thereof and having main bodies adapted to be secured to members to be joined and lying in a first plane when joined, (b) for each piece of material a row of fastener elements along the edge portion to be joined, each fastener element having a shank and an enlarged head at one end of the shank and the heads of each row of elements fitting, when the joint is closed, between the shanks of the elements of the other row and engaging behind the heads of the elements of the said other row, said fastener elements when engaged lying in a second plane offset from said first plane, (c) each piece of sheet material folded around the other ends of the shanks of the fastener elements of the row along the edge portion of that sheet with portions of said edge portions remote from said main body portions adapted to abut one another when said fastener elements are engaged, (d) for each piece of sheet material a row of outer elements of substantially U-shape, there being one outer element for each fastener element with the arms of the outer element embracing the folded part of the sheet material around the said other end of the shank of the fastener element as well as the end of the shank within the folded part, and (e) for each outer element and fastener element embraced thereby a rivet which passes through holes in the arms of the outer element, through the folded sheet material between the arms and through a hole in the shank of the fastener element, (1) said rivets securing said outer elements and said fastener elements to said folded material and (g) said rivets being secured to said arms and thereby tying said arms together and resisting bending open of said outer elements by forces pulling in said first plane in offset relation to said second plane and applying said forces to press together said portions of said sheets remote from said main bodies.
2. A sliding clasp fastener having: (a) two pieces of sheet-like flexible material to be joined together along edge portions thereof, (b) for each piece of material a row of fastener elements along the edge portion to be joined, each fastener element having a shank and an enlarged head at one end of the shank and the heads of each row of elements fitting, when the joint is closed, between the shanks of the elements of the other row and engaging behind the heads of the elements of said other row, (c) each piece of sheet material folded around the other ends of the shanks of the fastener elements of the row along the edge portion of that sheet, (d) for each piece of sheet material a row of outer elements of substantially U-shape, there being an outer element for each fastener element with the arms of the outer element embracing the folded part of the sheet material around the said other end of the shank of the fastener element as well as the end of the shank within the folded part, (e) the mouths of the outer elements of the two rows facing towards one another, when the joint is closed, and each outer element of one row having an arm of which the end face is at least partly opposite to and substantially in direct contact with the end face of an arm of an element of the other row, and (1) portions of the sheet material folded over and around the ends of the other arms of the outer elements, the portions so folded being held in face to face abutting relation in the closed joint.
3. A sliding clasp fastener as claimed in claim 2 having the edge of each piece of sheet material located between the said one arm of each of the outer elements which embrace that sheet and the fastener element embraced by that element and in pressure contact with the edge of the other piece of sheet material.
4. A sliding clasp fastener as claimed in claim 3 in which each piece of sheet material has a fold at which the material is doubled on itself and the fold constitutes the edge aforesaid.
5. A sliding clasp fastener as claimed in claim 2 and having for at least some of the outer elements, pins which pass through the arms thereof and through the sheet material and shanks of the inner elements embraced thereby.
References Cited in the file of this patent UNITED STATES PATENTS 2,031,959 Kelley Feb. 25, 1936 2,775,012 Mulka Dec. 25, 1956 2,791,017 Mulka May 7, 1957 2,959,833 Ryser Nov. 15, 1960 2,993,252 De Held July 25, 1961 FOREIGN PATENTS 1,164,115 France Oct. 6, 1958 867,519 Great Britain May 10, 1961