GB2062085A - Clamping Assemblies and Screw Clamps for Use Therewith - Google Patents

Abstract

Clamping assembly comprises a pair of clamping elements (4, 5), such as enamelled flanges, and a screw clamp including a C-shaped member (1) defining a pair of jaws of which one has a clamping portion (2) and the other has a threaded bore (6) receiving a clamping screw (7) with another clamping portion (8). one of the clamping portions (2, 8) is arranged to engage in a corresponding recess (3, 9), such as a groove, in a respective clamping element (4, 5). When an article to be clamped between the elements (4, 5) is located therebetween, with the or each clamping portion (2, 8) in register with the corresponding recess (3, 9), and the clamping screw (7) is tightened, the or each clamping portion (2, 8) engages in its recess to clamp the article between the clamping elements. In the embodiment of Fig. 6, a series of clamps are pivoted together to form a chain of clamps. <IMAGE>

Description

SPECIFICATION Clamping Assemblies and Screw Clamps for Use Therewith This invention relates to clamping assemblies and to screw clamps for use with such assemblies. The invention is especially, but not exclusively, related to clamping assemblies comprising at least one screw clamp and a pair of flanges, such as, enamelled flanges, with an article clamped therebetween.

Known forms of screw clamp for enamelled flanges consist of four components and, although these clamps have proven useful for some time, particularly, in chemical apparatus construction, they have certain inherent disadvantages. Firstly, the thread of the clamping screw is a region of weakness, in that it is subjected to considerable bending and tensile stresses. When overloaded, the clamping screw will break in this region of weakness. Secondly, when the clamping screw is tightened and at the initial instant of applied stress, the friction under the associated nut fluctuates within broad limits, due to the inaccurately defined angular position of the corresponding cap component with respect to the nut. Additionally, the frictional forces associated with the movement of the clamping screw toward the cap vary greatly.Furthermore, these known screw clamps tend to slide off the enamelled flanges, radially with respect to the flanges, during use and this major disadvantage can only be overcome by providing additional means, such as welded-on rings or studs on the flange peripheries, to retain the clamps in position.

It is an object of this invention to provide an improved clamping assembly, particularly for use with enamelled flanges, which overcomes the above-described disadvantages associated with known clamping assemblies and their associated screw clamps. In accordance with a first aspect of the invention, there is provided a clamping assembly comprising a pair of clamping elements capable of receiving therebetween an article to be clamped and a screw clamp comprising a member, defining a pair of jaws of which one has a clamping portion and the other has at least one threaded bore, and a clamping screw threadedly adjustable in the or each bore and having a clamping portion, at least one of the clamping portions being arranged to engage in a corresponding recess in a respective clamping, the arrangement being such that, when:: (a) an article to be clamped between the elements is located therebetween; (b) the or each clamping portion is located in register with the corresponding clamping element recess; and (c) the or each screw is adjustably tightened, such that the or each clamping portion engages in its corresponding recess, the article is clamped between the clamping elements.

Preferably, the member is substantially Cshaped and each clamping portion may be arranged to engage in a corresponding recess in a respective clamping element. Alternatively, one clamping portion may be arranged to engage a substantially planar surface of a respective clamping element. The head of the or each screw can be located in an enlarged portion of its associated bore and, also, the or each screw can have a two-part threaded shank, with a cup spring located between the two parts. Advantageously, the head of the or each screw has a transverse hole passing therethrough and capable of receiving connecting wire.

The central portion of the clamp member can be detachably secured to another clamp member by means of a chain link connection and, preferably, the corresponding recess in the or each clamping element is in the form of a groove, in which case, each element can be in the form of a flange, with each groove being located at or adjacent the periphery thereof.

In accordance with a second aspect of the invention, there is provided a screw clamp as defined above.

Various embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figs. 1 to 3 show partial sectional views of three forms of construction of clamping assemblies; Figs. 4 to 6 show elevational views of three forms of screw clamp; Fig. 7 shows a modified form of screw clamp, in which a cup spring is incorporated; and Figs. 8 and 9 show elevational views, in partial section, of yet two further forms of screw clamp.

Referring to Fig. 1, a clamping assembly comprises a screw clamp having a substantially C-shaped bracket number 1 defining a pair of jaws. The lower jaw has a tapered clamping portion 2 which engages in a corresponding recess, in the form of an annular groove 3, in the periphery of one 5 of a pair of enamelled flanges 4, 5. The clamping portion 2 has a 450 taper such that its apex angle is 900 and corresponds with the, or substantially, the, same angle at the base of the groove 3. Thus, the clamping forces of the screw clamp upon the assembly are fully utilized, due to this correspondence between the shapes of the clamping portion 2 and the groove 3.

The upper jaw of the C-shaped member 1 has a threaded bore 6 in which is threadedly received a clamping screw 7 with a hardened core end 8 which engages in a corresponding recess, preferably in the form of an annular groove 9, in the periphery of the other 4 of the pair of enamelled flanges 4, 5. As in the case of the clamping portion 2 and corresponding groove 3, the core end 8 engages with the corresponding groove 9 such that the clamping forces upon the assembly are fully utilized.

As can be seen in Fig. 1, the flanges 4, 5, constituting a pair of clamping elements, have clamped securely therebetween an article in the form of a packing.

An eye 10 is provided adjacent the lower jaw of the bracket member 1 and serves to receive a locating ring or the like for holding the unscrewed screw clamp in position. A number of such screw clamps can be located around the periphery of the pair of enamelled flanges 4, 5, depending upon the actual application of the assembly and the article to be clamped therein.

The clamping assembly shown in Fig. 2 is similar to that described with reference to Fig. 1, except that the bore 6 has an enlarged portion 11 which receives the head 7' of the clamping screw.

The clamping assembly shown in Fig. 3 is again similar to that described with reference to Fig. 1, except that the screw clamp is inverted and the head of the clamping screw 7 has a hole 12 passing therethrough. This hole 12 can accommodate a locating ring, wire or the like and serves the same purpose as the locating ring, in association with the eye 10, described with reference to Fig. 1.

In Fig. 4, there is shown a substantially Cshaped bracket member 1 which is similar to those described above with reference to Figs. 1 to 3. However, the clamping portion 2 in this member is slotted, as indicated by reference numeral 13. This slot effectively provides a pair of clamping portions 2 of which each can be located and engaged in a respective recess in the corresponding flange (not shown).

As shown in Fig. 5, two clamping screws 7 can be used with one clamping member 1, the axes of the screws being parallel and there being two threaded bores in the upper jaw. This embodiment is particularly useful for clamping manhole covers, wherein only four such screw clamps need be used, instead of twelve conventional clamps, as in the case of the prior art.

In Fig. 6 there is shown a plurality of screw clamps having their substantially C-shaped bracket members 1 interconnected, at their central portions, by a chainlink type connection.

By providing enough interconnected members 1, a closed ring of clamps can be provided around the periphery of the pair of flanges. However, in this embodiment of clamping assembly, each lower clamping portion 2' has a planar surface for engaging with a corresponding planar surface on the associated flange. This is because, with a closed ring of clamps having shaped clamping portions at one jaw engaging with correspondingly-shaped recess in the associated flange periphery, one flange usually tends to become closely clamped, owing to the rigidity of the ring of interconnected screw clamps.

Similarly, the hardened end 8' of each clamping screw need not be cored, in which case, no recesses or annular groove need be provided on the associated flange.

The embodiment shown in Fig. 7 illustrates a modified form of clamping screw 7 for use with the assemblies and changes described above with reference to Figs. 1 to 6, or those described below with reference to Figs. 8 and 9.

In Fig. 7, the screw 7 comprises, at the end of its threaded shank portion 1 5, a guide bolt 16, which centres a cup spring set 18, and a pressure bushing 17, slidingly located on the end of the bolt 16. The upper jaw of the C-shaped member 1 is reinforced to accommodate this form of modified clamping screw. The maximum initial stress (tension) of the cup spring set 1 8 is attained when the free end surface of the guide bolt 1 6 abuts the closed end of the box in the bushing 1 7. Overloading of the cup springs is thus eliminated. Additionally, the use of the cup spring set 1 8 permits a proper clamping action when the clamping screw 7 cannot be tightened down securely.

The embodiment shown in Figs. 8 and 9 is a combination of the features of the screw clamps shown in and described with respect to Figs. 2, 4 and 5. In this arrangement there are provided two clamping screws 7' with each of their heads accommodated in an enlarged portion 11 of the respective bore 6. Also, the lower clamping portion 2 is divided into portions by a slot 13 and an eye for a locating ring 19 or the like is provided adjacent the lower jaw of the C-shaped member 1.

Claims (22)

Claims

1. A clamping assembly comprising a pair of clamping elements capable of receiving therebetween an article to be clamped and a screw clamp comprising a member, defining a pair of jaws of which one has a clamping portion and the other has at least one threaded bore, and a clamping screw threadedly adjustable in the or each bore and having a clamping portion, at least one of the clamping portions being arranged to engage in a corresponding recess in a respective clamping, the arrangement being such that, when: (a) an article to be clamped between the elements is located therebetween; (b) the or each clamping portion is located in register with the corresponding clamping element recess; and (c) the or each screw is adjustably tightened, such that the or each clamping portion engages in its corresponding recess, the article is clamped between the clamping elements.

2. An assembly according to claim 1, wherein the member is substantially C-shaped.

3. An assembly according to claim 1 or 2, wherein each clamping portion is arranged to engage in a corresponding recess in a respective clamping element.

4. An assembly according to claim 1 or 2, wherein one clamping portion is arranged to engage a substantially planar surface of a respective clamping element.

5. An assembly according to any preceding claim, wherein the head of the or each screw is located in an enlarged portion of its associated bore.

6. An assembly according to any preceding claim, wherein the or each screw has a two part threaded shank and a cup spring located between the two parts.

7. An assembly according to any preceding claim, wherein the head of the or each screw has a transverse hole passing therethrough and capable of receiving a wire.

8. An assembly according to any preceding claim, wherein the jaw clamping portion is slotted.

9. An assembly according to any preceding claim, wherein the central portion of the clamp member is detachably secured to another clamp member by means of a chain link connection.

10. An assembly according to any preceding claim, wherein the corresponding recess in the or each clamping element is in the form of a groove, each element being constituted by a flange and each groove being located at or adjacent the periphery of the respective flange.

1 A screw clamp as defined in any of claim 1 to 9.

12. A clamping assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

1 3. A screw clamp substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

14. A clamping assembly comprising a pair of clamping elements capable of receiving therebetween an article to be clamped and at least two screw clamps each comprising a member, defining a pair of jaws of which one has a clamping portion and the other has at least one threaded bore, and a clamping screw threadedly adjustable in the or each bore and having a clamping portion, the clamping portions being arranged to engage a corresponding surface on respective clamping elements and the or each screw clamps being pivotally interconnectable, the arrangement being such that when: (a) an article to be clamped between the elements is located therebetween; (b) the clamping portions are located in register with the corresponding clamping element surface; and (c) the screws are adjustably tightened, such that each clamping portion engages its corresponding surface, the article is clamped between the clamping elements with the or adjacent clamps pivotally interconnected.

1 5. An assembly according to claim 14, wherein the member is substantially C-shaped.

16. An assembly according to claim 14 or 15, wherein the head of each screw is located in an enlarged portion of its associated bore.

1 7. An assembly according to claim 14, 1 5 or 16, wherein each screw has a two-part shank, with a cup spring set located between the two parts.

18. An assembly according to any of claims 14 to 17, wherein each screw has a transverse hole passing therethrough and capable of receiving a locating connecting ring, wire or the like.

1 9. An assembly according to any of claims 14 to 18, wherein each element is a flange.

20. At least two interconnected screw clamps as defined in any of claims 14 to 1 8.

21. An assembly in accordance with claim 14, substantially as hereinbefore described with reference to and as shown in Fig. 6 of the accompanying drawings.

22. At least two interconnected screw clamps substantially as hereinbefore described with reference to and as shown in Fig. 6 of the accompanying drawings.