GB2145150A

GB2145150A - Binding strap

Info

Publication number: GB2145150A
Application number: GB08419389A
Authority: GB
Inventors: Guido Vergari
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-29
Filing date: 1984-07-30
Publication date: 1985-03-20
Also published as: DE3427693A1; FR2549923A1; GB8419389D0; IT1163880B; IT8322361A0

Abstract

A flexible band-clamp of plastics material for binding detached elements, particularly filiform continuous lengths 8, comprises a band (1), having on one side serrations (2), and an apertured head (3) integrally moulded at one end of the band (1) and having an inclined inner surface (10). An insert (5) is housed in the head (3) and has one surface provided with serrations (6) and another bearing projections (7). In operation, the serrations (6) engage with serrations (2) of the band (1) and the inclined projections (7) with the corresponding inclined inner surface (10) of the head (3). The insert (5) is linked to the head (3) by a flexible portion (11) which permits a sliding action. Preferably two projections (7) are provided. <IMAGE>

Description

SPECIFICATION Binding strap This invention relates to a flexible binding strap.

Description of the prior art In orderto hold and bind together a plurality of filiform elements, generally a flexible binding strap is used which surrounds the bundle, tightens around it and is securely fastened.

The filiform elements may be the electrical cables to be bound together in the control gears, along the distributing and feeding lines of the power devices or electrical and telephonic connecting and distributing lines.

The known binding straps, made of plastic material, generally comprise an eyed head at one end of the strap, provided with a retaining one way cogging element (pawl) housed into the head, and a flat plastic ribbon having on one side a serration which engages the cogging element in the head.

The closed strap takes on an almost continuous circular shape and accordingly resists the stress to open the formed ring, i.e. the stress to pull the strap out of the head.

In the known binding straps, the eyed head may be not moulded in one piece with the strap body, but it is a loose piece, although inseparable, at one end of the strap, or it may be made by one mold. In this case, the eyed head is one unit with the strap and contains a metal pawl or a plastic flexible serrated pawl for gripping the strap body.

In the known binding straps, the head gripping mechanism represents the weak point of the system. In fact, the gripping elements show limited mechanical robustness both for their design as well as for the mutual engagement position of the gripping parts, since they are subject to a reciprocal separation by the opening stress of the strap ring with consequent release of the strap by the pawl.

The tensile, applied to the strap ring, which causes it to open, is considered as the mechanical strength value of the straps, whereas the true mechanical strength (i.e. the ultimate tensile stress) of the strap body is always much higher.

Summary of the invention The object of the present invention is to provide a binding strap having a very high gripping power in the head.

According to the present invention, this and other objects are achieved by a binding strap comprising: a ribbon shaped body having on one side a serration; an eyed head, integrally moulded at one end of said ribbon shaped body and having an inclined inner surface; and a solid slidable insert housed into the eyed head and provided with two gripping means engaging respectively with the serration of the ribbon shaped body and with the inclined inner surface of the eyed head.

Afirstfeature of the present invention consists in replacing the usual metallic or plastic serrated pawl, housed in the head for gripping the strap, with a solid insert, attached to the head upon molding by means of an adequate cord, which allows it to slide and to be displaced upward and backwards to make room for the strap to be passed through the opening of the head.

The strap shows the serrated side to the slidable insert, whose corresponding side is serrated with an equal and opposite ratchet gear in order to perfectly cage the two facing sides at the end of the strap pull, i.e. when the cables to be bound are fully tightened.

The other side of the slidable insert is provided with two symmetrical projections, having inclined planes to which a corresponding inclined plane, obtained in the inner side of the rear head wall, makes a pendant.

When the pull on the strap body stops for full tightening of the cables, due to the shrinkage of the elongated strap, the strap serration engages that of the mobile insert which is pulled downwards and also forwards against the strap by its inclined planes which run on the opposite inclined plane of the eyed head rear wall internal side.

This results in the full cogging of the two facing serrations and in the compression of the strap body against the inner vertical surface of the front side head wall, compression which is tighter, the stronger the strap pulls on the slidable insert.

Consequently, therefore, an overtension of the strap body, which causes a defective binding in the models with metallic or plastic serrated pawls, gives only a positive result in the present device.

Another feature of the present invention is that the centerline of the head gripping system is not radial to the cables bundle, as it is in the conventional models having metallic or plastic serrated pawls, but it is tangential to the cables bundle.

This results in that the pull direction, applied to the strap body by the cable binding or by the tensile testing machine, wedges in more and more the slidable insert into the head and consequently makes tighter and tighter and more and more cooperating the locking of the strap by the mobile insert between the front inner vertical wall and the rear inner inclined wall of the eyed head.

In the previous device, the pull direction applied to the strap body, on the contrary, tends to move away each other the engaged pawl and strap serrations with consequent release by the head much before the ultimate tensile stress of the strap body is reached.

The mechanical strength of the head gripping mechanism therefore results to be much higher than that of the metallic or plastic serrated pawls and at the most reaches the ultimate tensile strength of the strap body.

Brief description of the drawing The present invention will be hereinafter described in detail with reference to the drawing which illustrates a preferred, exemplified and not limitative embodiment of the present invention and wherein: Figure 1 illustrates the prospective view of the binding strap of the present invention; Figure 2 illustrates the schematic view of the cross-section of figure 1, by a plane passing through the line Il-Il; and Figure 3 illustrates the schematic view of the binding strap of figure 2 after binding and tensioning on the cable bundle.

Description of the preferred embodiment With reference to the embodiment illustrated in the figures, the binding strap of the present invention comprises a ribbon 1, having one side 2 serrated. The length and cross-section area of the ribbon 1 may be selected and proportioned to the use requirements.

The ribbon 1 terminates at one end (not shown in the figures) in a tapered and thinned tail and, at the other end, it is integral with an eye shaped head 3, provided with a strap gripping element 4.

Within this eye head 3 a solid insert 5 is housed, integral with a head wall but free to slide. The solid insert 5 bears on the front side in upward serration 6 and on the opposite side two inclined slide projections 7. The solid slidable insert 5 is integral with an head wall by means of a flexible molded cord 12 with a single (as in the figures) or multiple loop.

The head walls are preferably tapered outside; while, the inside wall part 9, in front of the slidable insert serrated side 6, is nearly vertical and parallel to said side 6, and the inside wall part 10, in front of the slidable insert projections 7, is inclined.

The slope of the wall part 10 is coordinated with the slope 11 of the two projections 7 so that when the serration 6 is pushed backward by the thickness of the inserted strap body 1, the slope 11 comes into contact with the slope 10.

Then, when the strap body 1 (see figure 3) is admitted through the lower head opening 13, it does not meet any difficulty, as the slidable insert 5 moves and rises, on pulling the cord 12 to make room for the strap body 1 to pass through the head 3.

The body serration 2 maintains always a sliding contact with the serration 6. When a cable bundle 8 is tightened and the pull, applied to the body 1, is released, the two facing serrations 2, 6 become cogged and the strap body's tension pulls down the slidable insert 5, which, owing to the planes 11 sliding on the plane 10, pushes the two cogged serrations 2, 6 against the vertical wall 9 with a consequent absolute gripping of the strap body 1.

The strap body tension in fact can never admit the strap body to be released.

The dimensions and the measurement of the various constituting parts are those required by the use which any strap is designated to.

In the practical embodiment of the present invention, modifications, variations andlor alterations of the parts constituting the above described binding strap may be made within the scope of the present invention.

Claims

1. Flexible binding strap made of plastic material, for holding and binding detached elements, particularly filiform continuous wholes, comprising a ribbon shaped body having on one side a serration; an eyed head, integrally moulded at one end of said ribbon shaped body and having an inclined inner surface; and a solid slidable insert housed into the eyed head and provided with two gripping means for engaging respectively with the serration of the ribbon shaped body and with the inclined inner surface of the eyed head.

2. Flexible binding strap according to claim 1, wherein the gripping means for engaging with the serration of the ribbon shaped body is a serration molded on a side parallel to the vertical wall of the eyed head and oriented in the opposite direction of said ribbon shaped body's serration.

3. Flexible binding strap according to claim 1 or 2, wherein the gripping means engaging with the inclined inner surface of the eyed head is formed by one or more projections located on the opposite side to the serrated one and having inclined planes sliding on the opposite inclined surface of the eyed head.

4. Flexible binding strap according to claim 3, wherein the planes of the projections are inclined towards the head centerline.

5. Flexible binding strap according to any preceding claims, wherein the solid slidable insert is integrally moulded with the head wall by a flexible cord.

6. Flexible binding strap according to claim 5, wherein the flexible cord is provided with a single or multiple loop.

7. Flexible binding strap made of plastic material, for holding and binding detached elements particularly filiform continuous wholes as above described and illustrated in the figures of the