GB2098267A

GB2098267A - A band clamp

Info

Publication number: GB2098267A
Application number: GB8207330A
Authority: GB
Original assignee: Hymatic Clamps International Ltd
Current assignee: Hymatic Clamps International Ltd
Priority date: 1981-03-12
Filing date: 1982-03-12
Publication date: 1982-11-17
Also published as: GB2098267B

Abstract

A band clamp (110) has an end portion (113) which can partly overlap with another end portion (112). To tension the clamp, boundaries of apertures (117) in the end portions are engaged by a tightening device which establishes tension in the clamp. The overlapping end portions are then welded or riveted together. Other forms of abutment may be provided for engagement by a tightening device. <IMAGE>

Description

SPECIFICATION A band clamp and method of applying same Description of Invention From one aspect, the present invention relates to a method of applying a band to embrace a plurality of members. The invention is primarily concerned with a method of applying a V-band clamp, by which we mean a device comprising a band having a channel-shaped cross-section along at least a major part of its length and which device, in use, forms a closed loop and embraces members which are to be clamped together. The invention also relates to a clamp for use in the method.

Known V-band clamps include a screw and nut mechanism or other mechanism connected with opposite end portions of the band and operable to establish tension in the band when the band embraces members which are to be connected together. The provision on a V-band clamp of a screw and nut mechanism or other mechanism for tightening the clamp makes a substantial contribution to the overall cost of producing a Vband clamp.

According to a first aspect of the invention, there is provided a method of applying a band, preferably of a V-band clamp, to a plurality of members, wherein the band is placed around the members to embrace them collectively, with end portions of the band in mutually overlapping relation, the extent of overlap is increased to establish tension in the band and said end portions are then secured together to maintain the tension.

The end portions of the band may be secured together by welding or by means of rivets.

Securement of the end portions is not effected until the required tension has been established in the band.

Preferably tension is established in the band by force exerted on abutment surfaces of the clamp by means of a tensioning device and the tensioning device is removed from the clamp after the end portions of the band have been secured together. The tensioning device can be used for tightening another band clamp after removal, and so on, so that a saving in cost is made by using one device for tightening a plurality of clamps.

According to a further aspect of the invention, there is provided a V-band clamp having end portions adapted to overlap each other when the clamp is in use.

Preferred embodiments of the invention will now be described with reference to the accompanying drawings wherein: FIGURES 1 to 6 show different embodiments of the invention.

The Figures suffixed 'a' are, in each case, a radial view of a portion of the clamp and the Figures suffixed 'b' are corresponding axial views.

FIGURE 2c is a cross-section through the clamp shown in Figures 2a and 26.

Figure 6 shows, in addition to a band clamp, a tensioning device engaged with the clamp.

In Figures 1 a and 1 b, there is illustrated a Vband clamp 110 comprising a band 111 which has a channel-shaped cross-section and is formed of stainless steel by rolling. The drawings show a part only of the band, including end portions 112 and 113. The end portions are partly overlapped one with the other and have been secured together by welding so that the band is in the form of a closed loop.

During manufacture of the band clamp, a part 11 4 of the end portion 113 which is adjacent to a free end of the band, prior to welding of the end portions, is offset relative to the remainder of the end portion 11 3 by the thickness of the metal of which the band is formed so that when the part 114 is overlapped with the end portion 112 and is seated on the outwardly facing surface of the end portion 112, the end portions 112 and 113 generally lie at the same distance from an axis of the clamp. As can be seen from Figure 1 a, the axial dimension of the part 11 4 is less than that of the end portion 112 and of the remainder of the end portion 113.

There are formed in the end portions 11 2 and 113 respective apertures 117 bounded by surfaces which constitute abutment surfaces on the band 111 for receiving a force, whereby the band can be subjected to tension. The abutment surfaces are spaced apart by a distance which exceeds half the radius of the clamp.

In use, the band clamp is placed around members which are to be secured together so that the part 114 of the end portion 113 overlaps with the end portion 11 2. Force is then exerted on the abutment surfaces to increase the degree of overlap and establish tension in the band. Whilst the tension is maintained, the part 114 is welded to the end portion 112. The abutment surfaces are then relieved of the force. To facilitate welding at 11 8, the part 114 may be pre-formed with an aperture 125. The interface between the part 114 and the end portion 11 2 has a substantial extent in both the circumferential direction and the axial direction of the clamp. It will be noted that no part of the complete clamp projects far beyond the remainder of the clamp in a direction away from the axis.

The clamp illustrated in Figures 2a, 2b and 2c differs from that shown in Figures 1 a and 1 b only in that the end portions are secured together by means of a rivet, not by welding. Except for this difference, the preceding description is deemed to apply to the clamp illustrated in Figures 2a, 2b and 2c and corresponding parts are indicated in these figures by like reference numerals with the prefix 2 substituted for the prefix 1 used in Figures 1 a and 16.

The cross-sectional shape of the band, which is a flanged channel, is illustrated in Figure 2c. It will be noted that the rivet protrudes slightly at the internal face of the end portion 212 but there is ample space to accommodate the rivet head within the channel defined by the cross-section of the band.

The V-band clamp illustrated in Figures 3a and 3b includes a band which is similar to that illustrated in Figures 2b and 2c. End portions 312 and 313 of the band include respective elements 320 welded onto outer surfaces of the band. The elements 320 include respective upstanding fins 321 which project radially outwardly from the remainder of the band and overlap one another.

The interface between the fins 321 has a substantial extent in a direction radially of the axis of the band clamp and in a direction circumferentially of the band clamp. Each element 20 may be formed by a pressing operation.

In use of the band clamp illustrated in Figures 3a and 3b, the clamp is placed around the members to be clamped together with the fins 321 in face-to-face contact whilst there is a gap between the ends of the band proper. Parts of the elements 320 remote from the fins 321 constitute abutments 322 on which there can be exerted a force which increases the extent of overlap of the fins 321 and establishes tension in the band.

Whilst the tension is maintained, the fins are secured to each other by welding.

The band illustrated in Figures 4a and 4b differs from that illustrated in Figures 3a and 3b in that the fins of Figures 4a and 4b are secured together by riveting, not by welding. In other respects, the description of the clamp of Figures 3a and 3b is deemed to apply to the clamp of Figures 4a and 4b and corresponding parts are indicated in the latter Figures by like reference numerals with the prefix 4 in place of the prefix 3 used in Figures 3a and 3b.

The band clamp illustrated in Figures 5a and Sb has end portions 512 and 513 partly cut-away in a complementary manner so that the end portions can be partly overlapped with each other with an interface in a plane perpendicular to an axis of the band clamp. When the clamp is applied to members which are to be clamped together, force is exerted on the end portions at abutment surfaces bounding apertures 517 and the degree of overlap of the end portions is increased until the required tension is established in the band. The end portions are then welded together at the interface.

The band clamp illustrated in Figure 6 includes a main band part 611 formed of strip metal and having a transverse cross-section which includes an arched central portion and flat, substantially co-planar marginal portions. The strip metal is formed into an open loop so that opposite transverse edges of the strip metal are spaced somewhat apart. In respective end portions 612 and 613 of the main band part adjacent to these transverse edges, there are formed apertures, one in each end portion, the boundary surfaces of which constitute abutment surfaces on which tightening means for the band can bear.

The end portion 612 is extended by a separately formed element 614 which is secured by welding to the main band part at a position between the aperture therein and the transverse edge. The element 614 extends beyond this transverse edge to overlap partly with the end portion 613. The element 614 lies in face-to-face contact with the main band part at opposite sides of the gap between the transverse edges of the main band part. Initially, the extension 614 is not secured to the end portion 613 so that the clamp can be expanded somewhat and engaged over members which are to be held together. The clamp is then tightened by a device 615 which increases the degree of overlap between the element 614 and the end portion 613. When the required tension has been established in the band 611, the element 614 is welded to the end portion 613 in a known manner.

The tensioning device 615 comprises a hollow body 616 through which there extends an elongated member 61 7 which protrudes from opposite ends of the body. At one end of the member 617, there is laterally projecting lug 618 carrying a spike 619 which projects generally towards the hollow member 616. On the hollow member, there is a corresponding laterally projecting lug 620 carrying a spike 621 which projects towards and is aligned with the spike 619. Means are provided for moving the lugs 618 and 620 towards each other. For example, the body 616 may be an hydraulic cylinder in which there operates a piston secured on the elongated member 617.

The spikes 619 and 621 can be engaged in respective apertures formed in the end portions 612 and 613. To facilitate this engagement, portions of the band 611 bordering the apertures on the sides thereof nearest to the element 614 are raised somewhat relative to the remainder of the band 611, that is displaced radially outwardly relative to the remainder of the band from a central axis of the band.

The tightening device 61 5 may be used also with each of the other band clamps shown in the accompanying drawings.

The tensioning device may include, in place of a piston and cylinder unit, a screw and nut mechanism or a lever mechanism whereby a user can draw towards each other the abutment surfaces of the band clamp. It will be noted that, in each example illustrated, the abutment surfaces are spaced equally from opposite axial boundaries of the band clamp. This avoids a tendency for the tensioning device to twist relative to the band clamp.

The band clamps hereinbefore described may be used for clamping together end portions of two ducts. The ducts would be forced in a known manner at their ends with radially outwardly projecting lips or flanges. The band clamp would be expanded slightly and passed over the lip or flange on one of the ducts before the ducts are moved into mutually abutting relation. When this has been done, the band clamp is engaged over both lips or flanges so that the lips of flanges are embraced collectively by the band clamp. The band clamp is then tensioned and the overlapping end portions are secured together. The band clamp extends in a single turn about the ducts and the lips or flanges of both ducts are trapped together in the band.

Claims

1. A method of applying a band to a plurality of members wherein the band is placed around the members to embrace them collectively, end portions of the band are moved into mutually overlapping relation, the extent of overlap is increased to establish tension in the band and said end portions are then secured together to maintain the tension.

2. A method of applying to a plurality of members a V-band clamp comprising a V-band, wherein the band is placed around the members to embrace them collectively, end portions of the band are moved into mutually overlapping relation, the extent of overlap is increased to establish tension in the band and said end portions are then secured together to maintain the tension.

3. A method according to Claim 1 or Claim 2 wherein tension is established on the band by force exerted on abutment surfaces of the band by means of a tensioning device and the tensioning device is removed from the band after the end portions of the band have been secured together.

4. A method of forming a joint between two ducts wherein a V-band clamp is applied to end portions of the ducts by a method in accordance with Claim 2 or Claim 3 to secure the end portions of the ducts together.

5. A V-band clamp having overlapping end portions wherein one of said end portions includes an extension piece which has been formed separately from and secured to a main band part of the clamp to bridge a gap between ends of the main band part and to lie substantially in face-toface contact with the main band part at opposite sides of the gap.

6. In a combination, a V-band clamp and a tensioning device which can be repeatedly separated from and re-engaged with the clamp, the clamp having abutment surfaces engageable by the tensioning device for establishing tension in the clamp.

7. A method according to Claim 3 or a combination according to Claim 6 wherein the abutment surfaces are spaced radially outwardly from a radially inner boundary of the clamp when the clamp is in use.

8. A method according to Claim 3 or Claim 7 or a combination according to Claim 6 or Claim 7 wherein the abutment surfaces are spaced from each other by a distance which is greater than half the radius of the clamp.

9. A method according to any one of Claims 3, 7 and 8 or a combination according to any one of Claims 6 to 8 wherein the abutment surfaces are presented by a part or respective parts which is or are formed of sheet metal by a pressing or rolling operation and wherein each abutment surface is a severed edge face of the sheet metal.

10. A method substantially as herein described with reference to the accompanying drawings.

11. A V-band clamp substantially as herein described with reference to and as shown in Figures 1 a and 1 b or Figures 2a, 2b and 2c or Figures 3a and 3b or Figures 4a and 4b or Figures 5a and Sb or in Figure 6 of the accompanying drawings.

12. Any novel feature or novel combination of features described herein or as shown in the accompanying drawings.