IMPROVEMENTS TO MEANS FOR CLASPING THE EXTREMITIES OF THE METAL SHEET FORMING TIE-BANDS

Abstract: Improvements to means for clasping the extremities of the curved elastic metal band (2), forming the body of the clamp, wherein one of the extremities (1), which corresponds to the tongue (3), has two protecting perpendicular small columns (4, 5), aligned one after the other, obtained by drawing the material of the band where said columns originate, and the opposite extremity to be overlapped (6), presenting two through-holes (11, 12) wherein are introduced the two columns when the extremities of the curved metal clamp are overlapped, by application of a temporary pressure, the rear column (5) avoiding negative rotary movements around its connexion point, the shape of both columns being optionally trunco-conical.

Description: The subject of the present invention concerns improvements to means for fastening the ends of the sheet metal forming clips made of metal strip. At present, clips are known which consist of a metal strip, of the type which at one end has a fastening guide tongue, while at the opposite end of the said metal strip there are hooks provided near one end of the strip, while at the opposite end are the engagement openings, being complementary to one another so that once the metal strip is coiled onto itself it remains closed, forming a ring. These metal strips forming the clips also have projecting portions defined by an inverted "U"-shape, arranged in the circumferential direction of the clip. These parts in the shape of an inverted "U", also commercially called "lugs", are intended to allow the clip to be constricted by means of pliers, the jaws pressing one in the opposite direction to the other in order to effect deformation of the said inverted "U" by pressing radially against the inserted pipe. However, in this type the alignment of the ends needs to be more precise in order to obtain greater and more correct constriction. Included in the known type of clip with a tongue mentioned above, there are also others which have guide means to avoid such lateral deviation. In US Patent A-4622720 the clasping for extremities of the metal sheets is temporary and they are constituted for studs formed by the elevated curved opening of a transversal cut, subsequently pressed into a curve, close to one end of the metal band, while at the other end of the band there are transverse rectangular apertures one edge of each of which engages with the lifted edge of the locking stud, on the opposite end of the band, thereby forming an abutment, kept in counterpoise by the tendency of the two overlapping ends to pull apart. A vertical hook, as well as the studs, which is pressed into the corresponding wide rectangular aperture, opened in the other end of the metal band itself which, in order to avoid unintentional separation of the two ends, is slid into place over the edge of the pressed aperture. The reaction of separation from each other of the two ends of the ring which constitutes the metal clip is important. Therefore when joining the folded end of the belt there is created such a pronounced separation force that two ends of the curved metal strip are converted into an expanding spring. None of the solutions cited provides any security of alignment, without lateral deviation, of the tongue of one or the other end of the metal strip when the latter is forced to curve onto itself by overcoming the opposed expanding spring action. The preamble of claim 1 is derived from US-A-4 299 012. Lateral deviations of one end placed, under pressure, facing the other end of the same metal strip forming the clip, are produced by the inherent tendency towards separation of the ends of one and the same metal strip, by expanding spring action, the opposed elastic force of which is concentrated in the central part of the total length of the curve of the strip, tending, in the misalignment of the two ends placed facing each other under pressure, to escape, generally in opposite directions, from the said opposing force producing the constant effect of negative misalignment. Therefore any slight blow or push imparted to one of the ends which are overlapped and joined to each other, known at present, such as occurs during transport of the clips from one place to another before they are placed round the rubber pipe, is sufficient to cause a slight deviation of the misalignment of the two overlapped ends in tension, and therefore portions projecting from the line of alignment are negatively produced. These projections in addition constitute a projecting metal part with edges which, when the clip is constricted against the rubber pipe which it encloses, cause unwanted pinches which among other things produce incorrect seals. The present invention tends to obviate said deficiencies. These are accomplished by the features of the characterising clause of claim 1. A description is given below of a practical embodiment, provided by way of non-limitative example, of a clip according to these improvements, accompanied by a sheet of drawings in which Figure 1 shows a metal strip, open and partially coiled onto itself. Figure 2 shows a detail in section of the same clip as in Figure 1, with its ends overlapped, joined by fastening, without the permanent clinched joint having yet been produced. Figure 3 shows on a larger scale the joining of one end to the other of the actual strip forming the clip, with the clinching of the eyelet when the latter is in the shape of a small frustoconical column, and Figure 4 shows the same illustration with the cylindrical column, clinched. The invention consists in providing in the actual metallic material which constitutes one of the ends (1) of the metal strip (2) which constitutes the clip, such as that which has the projecting tongue (3) at its head, stamped portions (4 and 5) which on the opposite side emerge perpendicularly in the form of small columns. On the opposite end (6) of the actual metal strip (2), such as that which near the latter has the constricting "lug" (7) and the stepped portion (8) with chamber (9) deformed by pressing and two parallel cuts (10) for housing the tongue (3) of the opposite end, there are provided through holes (11 and 12) coinciding in position with the columns (4 and 5), when the curved clip (2), under pressure, has the opposed ends facing one another and in an overlapped position. On applying greater pressure to bring the aligned ends closer together, the temporary fastening of both aligned ends (1 and 6), under pressure, is achieved. In this phase, if the placing of the clip transversely round the pipe to be constricted. has not been correctly arranged, which may mean a negative result in the constriction, as often occurs with the creation of wrinkles in the wall of the pipe when the clip is badly arranged round it, the user may, without damaging the clip, begin again the operation of arranging the loop round the pipe. Once the clip is considered to be properly in place, the user can then proceed, with pressure pliers, to carry out the clinching of one of the two columns, the first (4). The clinching of this column (4) effects permanent joining of one aligned end to the other, overlapped end of the strip-clip. However, this column (4) still leaves the possibility of the two aligned, overlapped ends (1 and 6) having a rotational movement at the point of union, and in order to avoid this the clip user then proceeds to clinch the second and neighbouring column (5) of the upper end, which clinching prevents rotation on itself of one of the ends (1 or 6) relative to the other overlapped end (6 or 1). It is clear that with the creation of the columns (4 and 5) from the actual material of the strip (2), the operation of inserting any additional eyelet is rendered unnecessary. In addition to saving on this operation, the loss of already inserted eyelets is avoided, especially during transport from the factory to the point of use by the user. Another important detail, bearing in mind the utilisation of the clips, is that on the end from which the columns (4 and 5) rise, the opening which originates from their creation, is not completely weakened, since the actual material of the columns (4 and 5) provides it with suitable reinforcement, which reinforcement continues in the corresponding insertion opening (11 and 12) of the opposite end (6). Depending on the point at which the clips are positioned, it may be convenient for the flange (13) of the clinched column which is shown on a large scale in Figure 4 not to project from the surface of the upper overlapped end (6). The columns (4 and 5), instead of being cylindrical, are then frustoconical (Figure 3), so that at the moment of clinching, the frustoconical walls are pressed in the said shape against the metallic material of the openings (11 and 12) into which they are inserted from the opposite end. In this way, as can be seen from Figure 2, the joint is of the dovetail type, which avoids projection of the edge of the column.

Claims: Means for fastening the ends of the sheet metal forming clips of the type made of metal strip (2) which constitute the body of the clip and which on one of the overlapped ends, aligned head to head, there is a guide tongue (3) for obtaining the correct alignment and on the opposite end a chamber (10) for housing the said tongue (3), defined by a stepped portion and a depression produced by pressing of the central part facilitated by two parallel cuts arranged in a circumferential direction, situated at the side of a projection in the shape of a transverse bridge having an inverted "U"-shape (7), with joining of its two limbs in a circumferential direction, CHARACTERISED in that on one of the ends (3), the one corresponding to that with the tongue (3), there are two cylindrical or truncated cone-shaped pressed portions constituting perpendicularly jutting projections that are aligned one behind the other in the longitudinal direction of said metal strip (2), each forming a small column (4 and 5), of the actual material of the metal strip (2) on which they arise, and on the opposite end to be overlapped there are two round through holes (11 and 12), into which, when the curved metal clip has its juxtaposed ends overlapped, under temporary pressure, the second inserted rear column (5) prevents negative rotational movements about the point of union of the first coupled column (4) and subsequently the clinching of both is performed. Means for fastening the ends of the sheet metal forming clips of the type made of metal strip, according to the preceding claim, CHARACTERISED in that when it is desired to prevent the emergence of the end edge of each column (4 and 5) from the surface of the overlapped end, the columns (4 and 5) are then made frustoconical in shape.

Inventors: PALAU DOMINGUEZ RAMON, PALAU DOMINGUEZ, RAMON
Applicants: MIKALOR SA, MIKALOR, S.A.
Application year: 1996
Main classification: F16L33
IPC codes: F16L33