GB1583360A - Clip for securing a strap - Google Patents

Description

(54) CLIP FOR SECURING A STRAP (71) 1, EDMUND BENEDIKT WORINGER, a Swiss citizen, of Hofwiesenstrasse 15, 8135 Gattikon, Switzerland, do hereby declare the invention, for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a clip for securing a strap.

When securing hoses of resilient material, for example, to pipes, pipe fittings, or valves, a steel strap is usually wound in one or more turns around the hose and, by means of a clip and with the aid of a tensioning device, is tensioned and secured. In addition to being used on hoses as mentioned above, these tensioning straps are also used in mining operations for the purpose of reinforcing the ends of flat-sided or round wooden pit-props whilst in a more general way, any article such as a traffic sign can be secured thereby to bars, poles and standards.

The clips can be divided into at least two basic groups. In the first group a tensioning device is provided whereby the strap during tensioning is wound on to a mandrel, and in the second there is provided a screw-threaded mandrel, the screw-thread of which engages in notches in the tensioning strap or itself forms these notches, and which, when rotated, pulls the strap and therefore applies tension to it. A disadvantageous feature of these clips is that the tensile force is usually applied by means of a screwdriver and is therefore limited. These clips are therefore better suited to securing resilient hoses or tubes than to securing an article to a hard supporting element.

Clips that are suitable for the two abovementioned different possible fixing methods do not incorporate their own tensioning device but are merely provided with strap-retaining elements; the strap is tensioned by means of a separate tool and, in the tensioned condition, is held by the retaining elements.

One clip of this kind, subsequently - including in the claims - referred to as a clip of the type hereinbefore defined, for securing a strap around an object has a base with a central opening from which an upper part has been stamped, the upper part remaining connected by lateral walls along two opposite edges of the upper part and being severed along two further opposite edges whereat apertures are formed and through which two thicknesses of the strap can pass, retaining teeth being formed at one of the further edges of the upper part and a pair of securing tabs being formed on the base adjacent the other further edge. In use one end of the strap is hooked under the base. The strap passes back between the two tabs, under upper part via the two apertures, around the object, back between the two tabs and under the upper part again. At the retaining teeth the strap is bend back on itself so that the teeth grip the strap to retain any tension therein. The bent back end passes once more between the tabs which are bent over to secure the end and the two portions of the strap also between the tabs.

A clip of the type hereinbefore defined is generally secured as follows: A tensioning strap is introduced by one of its ends through the apertures, is placed between the tabs and is drawn tight around the article that is to be retained or secured, and the strap is pushed between the portion thereof that has been passed through the appertures and the base part and is bent over at the end of the base part and towards the lower face of the latter. The upper free end, which may still be connected to the roll of strap material, is then gripped by a tensioning tool and pulled until it lies tightly around the articles to be held. As this takes place, a mouthpiece of the tool moves into contact with the edges of the lateral walls between the base part and the top part, and the tool is thus supported on the clip. If the strap, tensioned in this manner, is bent upwards and towards the end where the tabs are, the teeth of the serrated side press into the strap and the strap is retained and can be severed and released from the tool. The strap is then hammered flat on to the clip, whereafter the tabs are bent over so that the end of the strap is secured.

It has been found in this procedure that, because the teeth are pressed into the strap and thus secure it, and because the tool is turned about the edge of the upper part which acts as an axis of rotation, the strip, already weakened by the impression of the teeth, can develop breaks which can be so severe that the strap tears. Therefore, in all instructions relating to the use of the tools, it is pointed out that when turning the tool about the serrated edge of the upper part, forming the axis of rotation, it is necessary to keep the tensile force applied by the tool constant and to reduce the tensile stress, which increases as a result of bending the strap around the edge, by adjusting the tensioning device to reduce the tension.

For this purpose, however, the tool has to be held in both hands, one hand being used for turning the tool and the other for reducing the tensile force. This can be achieved without difficulty only if the articles to be secured are firmly held in position without intervention by the operator and if the operator has a firm foot hold. However, if for example traffic signs have to be secured at a great height to a lighting standard or the like, it will be readily appreciated that two-handed operations are troublesome, apart from the fact that reduction of the addtional tension depends very considerably upon the finger-tip touch of the operator.

The object of the present invention is to provide an improved clip of the type hereinafter defined.

According to the invention there is provided a clip of the type hereinafter defined wherein the lateral walls extend in the direction away from the securing tabs beyond the retaining teeth.

A clip according to the invention will now be described in greater detail with reference by way of example to the accompanying drawings, in which: Figure 1 shows a side view of a tensioning tool, Figure 2 is a perspective illustration of a clip for securing a strap and embodying the invention, Figure 3 shows a section through a clip on a supporting surface, and the manner of applying the clip to the strap, Figure 4 shows, on a larger scale and in section, part of a clip of an earlier form, Figure 5 is an illustration similar to that of Figure 4, but shows the improvement introduced by the present invention, and Figure 6 illustrates a further form of clip according to the invention.

The tool shown in Figure 1 consists of a mouthpiece 1, a strap-retaining device 2, a screw-threaded spindle 3, a tensioning device 4, a carrier 5 and a strap-cutting device 6. The strap 7, shown as a dash-dot line to make it clearer, is drawn through the mouthpiece 1, the strap cutting device 6 and the strap-retaining device 2.

The mouthpiece 1 has two clamp-like lips 8 and 9 which are rigidly connected to the carrier 5. The lips 8 and 9 taper towards their ends and have rounded tips. The strap-cutting device 6 comprises a pivot pin 10 which is rotatably mounted in the carrier 5 and, in the zone of the lips 8 and 9, is recessed to leave only a segmental part 11 of a cylinder. Secured to the pivot pin 10 is a lever 12 which extends outwardly through an opening, not visible in this view, cut in the carrier 5. Remote from the mouthpiece 1 in the longitudinal direction of the carrier 5, is the strap-retaining device 2 which is likewise firmly secured to the carrier 5. The strap-retaining device 2 is mainly constituted by a rectangular retaining element 13 in which is formed a channel 14 for receiving a tensioning strap 7. A lever 16, mounted to rotate on a pivot 15, has, on the surface of its arm 17 projecting into the channel 14 a knurled or ribbed zone for retaining the strap 7 by frictional force when said strap is pressed against one side-wall of the channel 14. The screw-threaded spindle 3 is secured by means of a clamping pint 8 in the retaining element on that side of the element 13 remote from the mouthpiece 1.

At the end of the carrier 5 remote from the mouthpiece 1 is a bearing block 19 in which the screw-threaded spindle 3 is rotatably mounted. A bearing 20, for example a roller thrust bearing, serves to reduce the frictional force between the bearing block 19 and the tensioning device 4 which usually takes the form of a crank with a handle and a tapped bore. The crank may of course be of doublearm construction with two grips or a handwheel could be provided.

The mode of operation of this tensioning tool will be clear from its above-described construction. The strap 7 is inserted from the side into the mouthpiece 1 and into the recess at the side of the segmental part 11 of the pivot pin 10, and likewise from the side into the channel 14 in the strap-retaining device 2.

Then the lever 16 is pressed towards the carrier 5 and the strap 7 is thus clamped. By turning the hand crank of the tensioning device 4, the screw-threaded spindle 3 is pulled upwards as seen in the drawing, and the strapretaining device 2 thus moves away from the mouthpiece 1 and pulls the strap 7 after it. If, as this happens, the strap 7 is retained at its other end, it is tensioned when the mouthpiece 1 can be applied to a support. When the strap 7 is sufficiently tensioned, it can be severed by means of the strap-cutting device 6.

A clip for securing the two ends of the strap is illustrated in Figure 2. This perspective view shows the base part 21, the upper part 22 with the support edges 22a and 22b and the retaining teeth 23, as well as the two securing tabs 24. It can also be clearly seen that the cutting edges 23a of the retaining teeth are set back from the supporting edges 22a and 22b towards the securing tabs 24.

The mode of operation of the clip shown in Figure 2 and of the tensioning tool illustrated in Figure 1 will now be explained by reference to Figure 3. In the last-mentioned Figure, the reference numeral 30 designates a portion of a mast or pole or hose. The strap 7 is divided into four main portions distinguished by the addition of the letters a - d.

The strap 7 is held at its end 7d nearer the roll of strap material, and the leading end 7a of the strap is first pushed through the opening 25 between the base part 21 and the upper part 22 of the clip. The leading end 7a is then looped around the mast and the article to be secured and is again pushed through the opening 25 between the trailing end 7d of the strap and the base part 21 and is passed around the base part 21. Thus the leading end 7a of the strap lies between the surface of the mast 30 and the underside of the base part 21 of the clip.

The tensioning part 7b of the strap 7 passes round the mast 30 and returns to the clip as a tensioning part 7c. The trailing end 7d of the strap can thus still be connected to the roll of strap material (not illustrated). After the strap has been connected in this way to the mast 30 and the clip, it can be initially tensioned as much as possible by hand. By slightly cranking the strap up into the cutting edges 23a of the retaining teeth 23, these teeth can be engaged in the strap which is then held sufficiently firmly to enable the slight tensile force to be maintained. Then, as illustrated in Figure 1, the trailing end 7d of the strap is fitted in the tensioning tool and the latter is applied by the forward edges of the lips 8 and 9 to the edges 22a and 22b of the upper part 22. The strap 7 is then firmly clamped by means of the strap-retaining device 2 and is pulled by means of the strap-tensioning device 4. With a sufficiently firm pull, that is to say with sufficiently firm tensioning of the strap around the mast 30, the tensioning tool is swung about the edges 22a and 22b in the direction indicated by the arrow 31 and as far as possible.

The trailing end 7d of the strap is then severed from the roll of strap material by means of the strap-cutting device 6. The trailing end 7d of the strap that is now projecting from the clip is pressed between the securing tabs 24 on to the base part 21 for example by hammer-blows, and the securing tabs 24 are then bent over.

Figures 4 and 5 show on a larger scale a portion from Figure 3 with the tensioning tool at a midway position in its swinging movement in the direction indicated by the arrow 31. To enable the advantage achieved by the invention to be appreciated, an existing clip and a clip in accordance with the invention are illustrated in Figure 4 and Figure 5 respectively. Since these Figures correspond to a portion of Figure 3, the same reference numerals are used for like parts.

With the arrangement of the retaining teeth 23 in the earlier form of clip shown in Figure 4, the stretched strap 7c is in engagement with the retaining teeth 23 in the position of the tensioning tool shown in the drawing. If, with the tension on the tensioning tool kept constant, the strap 7d is bent over, it will be readily appreciated that the tension increases and the retaining teeth 23 bite more deeply into the strap 7d so that a break can occur under the greater tension occurring at this weakened zone.

A break can occur simply when applying the retaining means, but it may also occur much later, for example as a result of expansion caused by heat.

In contrast to this, with the proposed form of clip shown in Figure 5, the strap 7d is still not in engagement with the retaining teeth 23 in the same position of the tensioning tool as in the above example. As the end position, likewise illustrated in this Figure 5, of the swinging movement in the direction of the arrow 31 in Figure 3 shows, the strap 7d is engaged by the cutting edges 23a of the retaining teeth 23 only just before this end position is reached, and the increase in tensile force that then occurs cannot cause any dangerous damage to the strap so that the tensioning device 4 does not have to be actuated during the swinging movement for the purpose of gradually reducing the additional tension.

The drawings illustrate a clip produced in a single stamping and pressing operation as can be clearly seen from Figure 2 in that it shows the complementary edges of the retaining teeth 23 in the base part. However, the clip could be produced just as well by stamping and a subsequent pressing operation, and the opening 25 would then become rectangular, and a line of separation between the two end edges would be visible in the base part 21.

The extent to which the cutting edges 23a of the retaining teeth 23 are set back from the edges 22a and 22b will obviously depend primarily upon the dimensions of the strap, so that the distance A (Figure 5) is of course smaller in the case of weaker straps than with stronger ones.

The thickness of the material used for the clip, and particularly for its upper part 22, is of course likewise determined by the strap material that is used, and the height of the edges 22a and 22b and the ends of the lips 8 and 9 of the mouthpiece 1 are also determined by the thickness or strength of the strap.

For the straps at present in use, it has been found advantageous for the distance A to be between 1 mm and 5 mm and in particular between 1.5 mm and 4.5 mm.

With this arrangement whereby the retaining teeth 23 are set back rearwardly of the plane determined by the edges 22a and 22b, but with otherwise similar dimensions of the proposed new clip as illustrated in Figure 2, it is possible for the upper part 22 to be displaced towards the securing tabs 24 as a result of heavy pressure applied by the tension in the strap to the retaining teeth in the direction of the securing tabs 24.

To prevent this, a number of slight modifications are possible: a first possibility, using the same shape, is to increase the strength of the material either by selecting one having a higher elastic limit or by using a thicker material.

A further modification consists in the use of a different shape in which the upper part 22 can be extended beyond the rear edges of the side parts by an amount equal to the extent A to which the retaining teeth 23 are set back, so that basically the upper part 22 is displaced relatively to the securing tabs 24.

A particularly advantageous form of construction is illustrated in Figure 6, which shows a clip which is in principle the same as that seen in Figure 2. The reference numerals of Figure 2 have therefore been used in Figure 6 so that repetition of the description is not necessary. However, in contrast to the Figure 2 form of construction, the edge of the upper part 22 that faces the securing tabs 24 has a convex curvature 22c. The greatest distance in the middle of the clip is at least roughly equal to the distance A by which the retaining teeth 23 are set back. With a shape of this kind, it has been found possible to absorb all forces.

WHAT WE CLAIM IS: 1. A clip of the type hereinbefore defined wherein the lateral walls extend in the direction away from the securing tabs beyond the retaining teeth.

2. A clip as claimed in claim 1 wherein the lateral walls extend beyond the retaining teeth by a distance of at least 1.5 mm but not greater than 4.5mm.

3. A clip as claimed in claim 1 or claim 2 wherein the further edge of the upper part nearer the securing tabs projects beyond the lateral walls toward the securing tabs.

4. A clip as claimed in claim 3 wherein the said projecting further edge extends in convex curve.

5. A clip as claimed in claim 4 wherein the greatest extent to which the said edge projects beyond the lateral walls is subsequently equal to or is greater than the distance by which the lateral walls extend beyond the retaining teeth.

6. A clip for securing a strap substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 and 5 or in Figures 1 to 3 and 5 as modified by Figure 6 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. To prevent this, a number of slight modifications are possible: a first possibility, using the same shape, is to increase the strength of the material either by selecting one having a higher elastic limit or by using a thicker material. A further modification consists in the use of a different shape in which the upper part 22 can be extended beyond the rear edges of the side parts by an amount equal to the extent A to which the retaining teeth 23 are set back, so that basically the upper part 22 is displaced relatively to the securing tabs 24. A particularly advantageous form of construction is illustrated in Figure 6, which shows a clip which is in principle the same as that seen in Figure 2. The reference numerals of Figure 2 have therefore been used in Figure 6 so that repetition of the description is not necessary. However, in contrast to the Figure 2 form of construction, the edge of the upper part 22 that faces the securing tabs 24 has a convex curvature 22c. The greatest distance in the middle of the clip is at least roughly equal to the distance A by which the retaining teeth 23 are set back. With a shape of this kind, it has been found possible to absorb all forces. WHAT WE CLAIM IS:

1. A clip of the type hereinbefore defined wherein the lateral walls extend in the direction away from the securing tabs beyond the retaining teeth.

2. A clip as claimed in claim 1 wherein the lateral walls extend beyond the retaining teeth by a distance of at least 1.5 mm but not greater than 4.5mm.

3. A clip as claimed in claim 1 or claim 2 wherein the further edge of the upper part nearer the securing tabs projects beyond the lateral walls toward the securing tabs.

4. A clip as claimed in claim 3 wherein the said projecting further edge extends in convex curve.

5. A clip as claimed in claim 4 wherein the greatest extent to which the said edge projects beyond the lateral walls is subsequently equal to or is greater than the distance by which the lateral walls extend beyond the retaining teeth.

6. A clip for securing a strap substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 and 5 or in Figures 1 to 3 and 5 as modified by Figure 6 of the accompanying drawings.