GB2338526A - Ring clamp for connecting two tubes - Google Patents

Abstract

The disclosed ring clamp has two half-shells (10, 20), each having a first extremity with a bearing pad (12, 22) extending outwards, as well as a second extremity equipped with one of the elements (14, 22) of the means of connection used to connect the two second extremities of the half-shells removably. The section of said half-shells is substantially U-shaped, with the branches of the 'U' extending towards the interior and having the capacity to operate in conjunction with the protruding support surfaces on the extremities of the two tubes. The clamp comprises a tightening screw (30), the post (32) of which traverses the pierced holes of the bearing pads (12, 22). The length (L) of the post is at least substantially equal to the radius (R) of the ring clamp when closed, and said post is inserted loosely into the holes of the bearing pads. The elements (14, 24) of said means of connection are designed to unite in order to bring together the second half-shell extremities, or to separate in order to maintain said extremities apart while the post of the screw remains in place in the holes of the bearing pads.

Description

1 J RING CLAMP FOR CONNECTING TWO TUBES The present invention relates to a

ring clamp for connecting two tubes, whose opposite ends present bearing surfaces projecting with respect to the cylindrical outer surface of said tubes, the ring clamp comprising two half-shells each presenting a first end provided with a bearing pad which extends outwardly and presents a hole, as well as a second end provided with one of the elements of means of connection intended to rernovably assemble said second ends of the half-shells, said half-shells presenting, in their running part, a section substantially in the forTn of a U, of which the arms extend inwardly and are adapted to cooperate with said bearing surfaces of the two tubes, the ring clamp comprising a tightening screw, adapted to cooperate with the bearing pads and of which the post traverses the holes thereof Ring clamps of this type are known by Patents US-A-3 014 259 and US-A-3 964 773. In these ring clamps, the means of connection constitute, in fact, a hinge which, after the two half-shells have been connected, maintains them permanently fastened to each other. In order to position the ring clamp around the bearing surfaces of the tubes, the two half- shells are spaced apart, using the hinge in order to dispose them around the bearing surfaces of the tubes to be connected, and the two half-shells are brought together before sliding the screw in the holes in the bearing pads and tightening the ring clamp.

This manoeuvre is relatively easy, but requires a manipulation consisting, once the half-shells are placed around the bearing surfaces of the tubes, in sliding the screw in the bearing pads and in placing the nut on the screw before tightening this nut. The operator having to manipulate the ring clamp must therefore have three separate parts available, namely the two half-shells assembled on one another, the screw and the nut. Finally, he must assemble these three parts, which may be the cause of a certain loss of time, all the more so as the relatively small parts such as the screw or the nut risk slipping out of his hands and dropping on the ground.

Moreover, the ring clamps are most often delivered in the pre-assembled state, in which the screw and nut are already in place. The operation 2 consisting in installing the ring clamp must be preceded by the unscrewing of the nut and/or the removal of the screw from the holes of the bearing pads.

GB-A-2 094 385 shows another ring clamp of the above-mentioned type, of which the means of connection of the two half-shells comprise a pad provided with a slot in which another pad is engaged. In this document, the means of connection are presented as a means for limiting the number of parts of the ring clamp.

GB-A-2 094 385 does not specify the mode of assembling the ring clamp around the object to be clamped, but it seems that the only mode of assembly that can be envisaged is the same as that of the ring clamps of US-A-3 014 259 and US-A-3 964 773.

The drawings of GB-A-2 094 385 show that the tightening screw is relatively long since the length of its post seems slightly longer than the radius of the ring clamp in the tightened state. However, no particular comment is made on this subject and the length of the screw shown in the drawings does not have any technical justification.

The invention is applied to a ring clamp of the type mentioned above, of which the post of the screw presents a length of the same order of magnitude as the radius of the ring clamp in the tightened state. It aims at simplifying further the positioning of the ring clamp and at avoiding the manipulation of a plurality of separate parts.

This aim is attained thanks to the fact that the post of the screw is mounted slack in the holes in the bearing pads, a clearance being arranged in these holes, around said post, and that the elements of the means of connection are capable of being connected to assemble the second ends of the half-shells or separated to space said second ends apart, even if the post of the screw is in place in the holes of the bearing pads.

It will be understood that these arrangements make it possible to preassemble the various elements constituting the ring clamp totally, by passing the post of the screw through the holes in the bearing pads and by screwing the nut only partially, it remaining in the vicinity of one of the ends of the post of the screw. Conventionally, the ring clamp is delivered in this pre-assembled state. To place the ring clamp in position, it suffices to separate the two ends of the half-shells by disengaging the means of connection and, by playing on the length of the post of the screw and on the clearance i 3 existing in the holes of the bearing pads around this post, to dispose the two half-shells one after the other around the bearing surfaces of the tubes, then to assemble the second ends of the half-shells before tightening the ring clamp normally, with the aid of the screw and nut. These manipulations are extremely simple and there is no risk of losing any one of the parts of the ring clamp when it is being placed in position.

The length of the post of the screw is chosen to be of the same order of magnitude as the radius of the ring clamp in the tightened state (it is question of the inner radius measured from the inner faces of the halfshells), as such a length, combined with the presence of the clearance between the post of the screw and the holes in which it is inserted, proves sufficient to allow the ring clamp to be placed in position without removing the screw.

For example, for a ring clamp with a radius included between 25 and 40 mm and of which the height of the branches of the U is substantially equal to 5 mm, a screw whose post measures 45 trim (its length is therefore slightly greater than the radius of the ring clamp) will be suitable, combined with a clearance of the order of 0.5 to 1.5 mm between the post of the screw and the holes in which it is inserted.

For ring clamps with larger radii, of the order of 45 to 50 mm, the height of the arms of the U remaining substantially equal to 5 mm, a length of post of the order of 45 mm (substantially equal to the radius) is also suitable, combined with substantially the same clearance. In fact, the length of post necessary depends on the ratio between the radius of the ring clamp and the height of the arms of the V. For conventional ring clamps, for which the height of the arms is greater, a length slightly greater than the radius will be necessary.

In general, a length of post included between once and twice the radius of the ring clamp in the tightened state, combined with a clearance of some tenths of millimeters to 1 or 2 mm of the post in the holes, allows the ring clamp to be placed in position without removing the screw. It should be noted that, in order to avoid tightening of the nut necessitating a large number of turns, it is preferable if the length of the post is at the most of the order of one and a half times the radius of the ring clamp in the tightened state.

The means of connection advantageously comprise a first lug, located at the second end of a first 4 half-shell, projecting substantially radially outwardly from the outer periphery of said first half-shell and presenting a free end curved inwardly to forTn a hook, as well as a second lug, located at the second end of the second half-shell, projecting substantially radially outwardly from the outer periphery of said second half-shell and adapted to cooperate with said hook.

The means of connection are thus made simply and economically. Moreover, insofar as they project radially with respect to the running periphery of the ring clamp, they may be engaged or disengaged without it being necessary to incline the two half- shells very strongly with respect to each other.

The invention will be more readily understood and its advantages will be more apparent from the following detailed description of an embodiment shown by way of non limiting example. The description refers to the accompanying drawings, in which:

Figure 1 is a view in elevation of a ring clamp according to the invention.

Figure 2 is a partial view in the direction of arrow II of Figure Figure 3 is a section along line III-III of Figure 1.

Figure 4 is a partial view in the direction of arrow IV of Figure 1 Figures 5 to 8 illustrate four successive phases of positioning the ring clamp on the ends of two tubes to be connected.

Figure 9 is a view similar to Figure 1, showing a variant embodiment of the ring clamp.

Figure 10 is a partial section along line X-X of Figure 9, and Figure 11 is a section along line X1-XI of Figure 10.

The ring clamp of Figure 1 comprises two half-shells 10 and 20 which each present a first end provided with a bearing pad 12 and 22 respectively, as well as a second end provided with a means of connection 14, 24 respectively. Considered jointly, elements 14 and 24 constitute means of connection which make it possible to assemble the two ends of the half shells 10 and 20 in removable manner. The bearing pads 12 and 22 extend outwardly of the ring clamp, i.e. they move away i from the centre of the ring clamp from the running periphery thereof The two pads 12) and 22 are parallel and extend overall in a radial plane of the ring clamp. The post 32 of a screw 30 passes through two aligned holes 12' and 14' respectively made in the bearing pads 12 and 22.

The two half-shells are made from a band of metal wound over substantially a half5 turn and suitably cold-hammered.

For tightening the ring clamp, the two ends of the half-shells 10 and 20 are assembled thanks to means of connection 14 and 24 and the nut 34 for tightening the screw is actuated so as to bring the two bearing pads 12 and 22 together. The head 36 of the screw cooperates with one of the bearing pads (12), while its nut 34 cooperates, directly or indirectly, with the other bearing pad (22). It will be noted that, in the example shown, a washer 38 is fixed to the bearing pad 22, the end 38a of this washer which is opposite the bearing pad 12 serving as stop for the nut during tightening. To be fixed, this washer is simply engaged in the hole 14' of the pad 22 and is riveted thereto by deformation of its end 38b opposite the said end 38a.

The means of connection 14 forms a first lug which is located at the second end of one of the half-shells ( 10). This first lug projects radially outwardly of the ring clamp from the outer periphery of this half-shell and presents a free end 14a which is curved inwardly to form a hook. The means of connection 24 forms a second lug which is located at the second end of the other half-shell (20), which projects substantially radially outwardly from the outer periphery of this second shell and which is adapted to cooperate with the hook 14a by engaging in the hollow thereof. The two lugs 14 and 24 project radially with respect to the running periphery of the ring clamp. The height h of the lug 24, measured from the free edge of the hook (height of engagement) is small, conventionally of the order of 2 to 5 mm, with the result that the hook 14 may be engaged on the lug without it being necessary to move the half-shell 10 too much towards the outside of the ring clamp with respect to the half-shell 20.

Moreover, it will be noted that the width 1 of the bottom of the hook is greater than the thickness e of the lug 24 (substantially 6 equal to one and a half times this thickness) to allow an easy engagement of the lu. 24 the hook 14a by a relative inclination of the two half-shells. To fix the ring clamp, the means of connection work like a hinge around which the half-shells pivot when the nut is tightened on the screw.

As shown in the section of Figure 3, the running parts of the half-shells present a substantially U-shaped cross section presenting a web 40 and two arms 41 and 42. Figure 3 also shows in light lines the ends of two tubes 44 and 46 presenting flanges 44a and 46a on which the half-shells of the ring clamp are placed. More precisely, the flanges present bearing surfaces 44b and 46b respectively with which the arms 41 and 42 of the U formed by the section of the half-shells cooperate, in order to tighten the tubes hermetically against one another.

The bearing surfaces 44b and 46b are in fact advantageously truncated, as are the arms 41 and 42, with the result that the fact of tightening the ring clamp effectively tends to bring the two tubes towards each other. By indicating that the section of the half-shells is overall in the form of a U, the fact is to be emphasized that the ring clamp presents, over the major part of its circumference, two re-entrant cheeks or walls 16 and 18 formed by the arms of the U, overall symmetrical with respect to its median plane P and adapted to cooperate with the bearing surfaces of the flanges formed on the ends of the tubes. The flat part 40 forming the base of the U, and defining the outer periphery of the ring clamp, may be more or less long depending on the dimensions of these flanges. It may even be virtually non-existent, in which case the section of the ring clamp would rathermore be in the form of a V.

The partial view of Figure 2 shows that the lugs 14 and 24 are formed by deformations of the ends of the half-shells, for example obtained by stamping. These latter are raised radially; the cheeks 16 and 18 are also raised and contribute to forming the lugs.

In the extreme, it may be chosen to use a screw constituted by a simple threaded post tightened with the aid of two nuts cooperating respectively with each of the bearing pads 12 and 22. Preferably, 1 7 as shown in Figure 1, a screw is rathermore used whose head 36 is integral with the post, only nut 34 having to be manipulated for tightening. In that case, the bearing pad 12 which cooperates with the head 36 of the screw is advantageously equipped with means for preventing rotation thereof.

More precisely, as shown in Figure 4, the head of the screw comprises at least one flat portion 36a (a polygonal head is for example simply chosen). As for the bearing pad 12 with which the head of the screw cooperates, it presents a flange 12a which extends away from the other bearing pad 22. This flange defines a housing 13 for the head 36 of the screw (it extends for example over a length slightly greater than the thickness of this head). Over at least a part of Its contour, the flange 12a presents a substantially flat portion 13a, adapted to cooperate with the flat portion 36a mentioned above. Simply, if a polygonal head is chosen, the flange is provided, in its part most remote from the running outer periphery of the ring clamp, with a similar polygonal shape, whose sides are slightly longer than those of the screw, so as to preserve a slight clearance f between the head of the screw and the flange.

In this way, the head 36 is not totally blocked which, as will be seen hereinafter, allows a slight relative clearance of the screw and the pad 12, but the head of the screw cannot rotate within the housing 13. To maintain the head inside this housing, the latter advantageously presents a wall element 15 which closes it partially on the side opposite the bearing pad 22.

This wall element 15, constituted for example by an extension of the flange 12a bent substantially at right angles, is made so as not to prevent the relative clearance of the screw and the bearing pad 12.

The flange 12a of the pad 12, like a similar flange 22a of the pad 22, also constitute means for rigidifying these pads, avoiding bending thereof when the ring clamp is tightened.

In Figure 1, reference j 1 designates the clearance which is preserved between the post of the screw and the hole 12' of the pad 12, and reference j2 the clearance which is arranged between the post of the screw and the inner periphery of the washer 38. It should be noted that, if the washer 38 were absent, 8 - 10 such a clearance J2 would be made between the hole 14' of the bearing pad 22 and the post of the screw.

The latter is mounted slack in the holes, which means that the clearances J 1 and j2 are sufficient to allow a displacement of the two half-shells with respect to the screw in the direction of arrows F 1 and F2 indicated in Figure 6, when the means of connection 14 and 24 are disengaged. To facilitate this displacement further, the inner periphery of the washer 38 is truncated and widens towards its end 38a. The angular clearance of the two half-shells with respect to the post of the screw in the direction of arrows F I and F2 necessary for fastening depends on the height of the arms 41 and 42 of the U (Figure 3) and, more precisely, on the height of overlap between arms 41 and 42 and flanges 44a and 46a. Such angular clearance is determined by the clearances j 1 and j 2.

It is observed in Figure 1 that the length L of the post of the screw is at least substantially equal to the radius R of the ring clamp in the tightened state. This arrangement makes it possible, when the nut is located at the end of the post of the screw, in its position indicated in broken lines, for the first ends of the half-shells 10 and 20 to be moved away from each other by sliding along the post over a sufficient length (substantially equal to the length L decreased by the thickness of the nut 34).

To position the ring clamp, which is initially pre-assembled (i.e. the screw is previously deposited in the holes of the bearing pads), the second ends of the half-shells 10 and 20 are firstly spaced apart, disengaging the means of connection 14 and 24. The first ends of the half-shells are then spaced apart by translating them with respect to each other along the post 32 of the screw. It should be noted that the nut is then located substantially at the end of the screw, in the position shown in broken lines in Figure 1, to have available a maximum amplitude of translation. The two half-shells are then pivoted with respect to each other around the post of the screw and a first half-shell is disposed on the bearing surfaces of the tubes. The situation shown in Figure 5 is thus attained. On this occasion, it is preferably the half-shell 20, the one which comprises lug 24, which is placed on the flanges of the tubes, the other 9 1 A half-shell 10 being pivoted substantially through a right angle (perpendicularly to the plane of the Figure).

By maintaining the half-shells spaced apart, the second half-shell (in the present case half-shell 10) is then turned down to return it into the plane of the first (20). On this occasion the second end of the halfshell 10 passes the obstacle constituted by the tubes and their flanges without difficulty, thanks to the fact that the length of the post is sufficient. One may also benefit from a slight angular clearance of the half-shell 10 with respect to the half-shell 20 in the direction opposite to arrow F2.

From this position, the two ends of the half-shells are assembled by engaging the means of connection 14 and 24. On this occasion, one also benefits from the capacity of clearance of the two half-shells with respect to each other, associated with the length of the post and its slack assembly in the holes of the bearing pads. Moreover, the means of connection advantageously having the shape of lugs 14 and 24 mentioned hereinabove, they may be engaged, without it being necessary to "open" the first ends of the half-shells too much. Figure 7 shows the phase of fastening in which, by using the clearance in the direction of arrows F 1 and F2, the hook 14 passes beneath the lug 24.

Finally, after fastening, it suffices to approach the first ends of the half-shells by a relative translation thereof along the screw, so as also to dispose the half-shell 10 on the bearing surfaces of the tubes. During this movement of relative translation, the means of connection are used as a hinge. The position shown in Figure 8 is then attained, from which it suffices to screw the nut to tighten the ring clamp with the aid of the screw.

In Figures 9 and 10, the elements similar to Figures 1 to 8 have the same references increased by 100.

The two half-shells 110 and 120 present a U-section of which the arms present slightly raised edges 11 Oa, 120a to extend axially, as shown in Figure 11 for half-shell 110.

1 The bearing pads 112 and 122 are reinforced by flanges or cheeks 1 12a, 122a which extend in the continuity of the arms of the U formed by the sections of the half-shells, without these arms turning, contrary to flanges 12a and 22a of Figure 1.

Consquently, in Figure 9, the head 136 of the screw 130 is not disposed in a housing.

To prevent the screw from rotating in the hole 112' of the bearing pad 112, the region of the post 132 of the screw immediately adjacent the head 136 presents a non- circular neck bearing 13 3 (for example a square neck bearing or a bead with a flat portion) and the hole 112, presents a shape with which this neck may come into engagement. As shown in Figure 10, the hole 112' is slightly larger than the neck 133 so that the clearance j 1 is preserved between the post of the screw and the edges of the hole 114'.

1 i 1

Claims (8)

1. Ring clamp for connecting two tubes (44, 46) of which the opposite ends present bearing surfaces (44b, 46b) projecting with respect to the cylindrical outer surface of said tubes, the ring clamp comprising two half-shells (10, 20; 110, 120) each presenting a first end provided with a bearing pad ( 12, 22; 112, 122) which extends outwardly and presents a hole (1 T, 14'; 11 T, 114), as well as a second end provided with one of the elements (14, 24; 114, 124) of means of connection intended to assemble said second ends of the half-shells in removable manner, said half-shells presenting, in their nmning part, a section substantially in the form of a U, of which the anns extend inwardly and are adapted to cooperate with said bearing surfaces of the two tubes, the ring clamp comprising a tightening screw (30; 130), adapted to cooperate with the bearing pads and whose post (32, 132) traverses the holes thereof, the post (32; 132) of the screw (30; 130) presenting a length (L) of the same order of magnitude as the radius (R) of the ring clamp in the tightened state, characterized in that said post is mounted slack in the holes (1 T, 14'; 1 IT, 114') of the bearing pads, a clearance G 1, j2) being made in said holes around the post (32; 132) of the screw (30; 130) and in that the elements (14, 24; 114, 124) of said means of connection are capable of being connected to assemble the second ends of the half-shells (10, 20; 110, 120) or separated to move said second ends apart, even if the post (32; 132) of the screw (30; 130) is in place in the holes of the bearing pads.

2. Ring clamp according to Claim 1, characterized in that the means of connection comprise a first lug (14, 114), located at the second end of a first half- shell (10; 110), projecting substantially radially outwardly from the outer periphery of said first half-shell (10; 110) and presenting a free end (14a) curved inwardly to form a hook, as well as a second lug (24, 124), located at the second end of the second half-shell (20, 120), projecting substantially radially 12 1 1 1 outwardly from the outer periphery of said second half-shell and adapted to cooperate with said hook (14a).

3. Ring clamp according to Claim 1 or 2, characterized in that, the screw having a head (36, 136) integral with its post (32, 132), it comprises means (13a, 36a; 133, 112) for 1 ring preventing rotation of the screw (30; 130) with respect to the hole (IT; 112 of the bea pad (12; 112) with which the head (36; 136) of the screw cooperates.

4. Ring clamp according to Claim 3, characterized in that, the head (36) of the screw presenting at least one flat portion (3 6a), the first bearing pad ( 12) presents a flange ( 1 2a) extending away from the second bearing pad, defining a housing (13) for the head (36) of the screw (30) and presenting, at least over a part of its contour, a substantially flat portion (13a) adapted to cooperate with said flat portion.

5. Ring clamp according to Claim 4, characterized in that the housing (13) presents a wall element (15) which closes said housing at least partially on the side opposite the second bearing pad (20) and maintains the head of the screw inside this housing.

6. Ring clamp according to Claim 3, characterized in that the post (132) of the screw (130) comprises a non-circular neck bearing (133) adjacent the head (136) of said screw and in that the hole (112) of the bearing pad (112) with which the head of the screw cooperates, presents a shape allowing engagement of the neck (133) against the edge of said hole (1 IT).

7. Ring clamp according to any one of Claims 1 to 6, characterized in that the hole of at least one (22) of the bearing pads is equipped with a washer (38) fixed to said bearing pad and of which the end (38a) opposite the other bearing pad (12) forms a stop for a nut (34) for tightening the screw (30).

8. Method for positioning a ring clamp according to any one of Claims 1 to 7, characterized in that, the screw (30) being previously disposed in the holes of the bearing pads (12, 22); the second ends of the half-shells (10, 20) are spaced apart, disengaging the means of connection (14, 24); the first ends of the half-shells are spaced apart by a relative translation of said first ends along the post (32) of the screw; the two half-shells are pivoted with respect to each other around the post of the screw; 13 a first half-shell (20) is disposed on the bearing surfaces of the tubes, maintaining the halfshells spaced apart; the second half-shell (10) is turned down to return it in the plane of the first; the two ends (14, 24) of the half-shells are assembled; the first ends of the half-shells are approached by a relative translation along the post (32) of the screw so as to dispose the second half-shell on the bearing surfaces of the tubes; and the ring clamp is tightened with the aid of screw (30).