US2746107A - Pressure clamps - Google Patents

Description

y 2 1956 H. MAHN 2,746,107

PRESSURE CLAMPS Filed Nov. 17, 1952 1N1 'm' me.

I s F i 5 Holbrook Mchn ATTORNEYS pressure is obtained.

which the clamp is applied.

United States Patent PRESSURE CLAMPS .Ho'lbrook Mahn, Englewood, Colo., assignor to Band-It This invention relates to pressure clamps and methods of applying the same.

Pressure clamps are useful for many purposes, such as for attaching hoses to nipples and the like; for assembling and repairing wooden water pipes, tying conduit or cable to pipes, girders and the like, clamping guy wire guards, fastening street and highway signs to poles, girders and the like, and other construction uses; for splicing electric welding cable, making up flexible cable line taps, and other electrical uses; and for repairing pipe or tank leaks, and other repair uses. Pressure clamps, of the type to which this invention relates, include generally a length of strap or strapping, normally metal, which extends around an article or portion thereof to which the clamp is to he applied, and a buckle or connector by which the ends .of the strapping are attached together. Such connectors should be adapted to permit the strapping to be pulled tight, prior to final attachment to the connector, and when a comparatively high clamping pressure is to be maintained, such as in attaching .high pressure hoses to nipples and the like, more than one .revolution of the strap is generally desirable.

It is customary toattach one end of a length of strap to the buckle or connector, pass the other end of the strap around the article to be clamped one or more times, and then use a special tool to exert a suificient pull on the free end of the strap, so that the desired clamping Such a tool may be of the type shown in U. S. Patent No. 2,208,114, and may include a slide which is provided with a strap gripping device and is movable along a frame, as by a screw, to apply tension on the strap with the nose of the tool abutting against the buckle or connector. A cutter is mounted in the nose of the frame, for cutting off the unused portion of the strap, while the nose of the tool frame and also the slide are provided with a guide slot for the strap, which is open at one side to facilitate insertion of the strap. .One type of buckle or connector is provided with ends and sides, an offset transverse central rib, and an upstanding ear at each side, the latter being hammered down over the end of the strap, after the desired tension has been placed thereon and the strap has been bent back over the buckle and the free end cut 01%. The fixed end of the strap is bent around underneath the central buckle rib prior to installation, and lies against the article to Tools and buckles of the above types are sold widely, being used particularly when extremely high clamping pressures are desired. Such buckles and the straps utilized therewith may be made of stainless steel to provide substantially maximum material strength, but the buckles require relatively complicated stamping operations for manufacture. Also, in the complete clamp, the free end of the strap is exposed and tends to extend from the buckle, thus tending to catch on objects or clothing, as when used as hose clamps. Furthermore, after the free end of the strap has been cut off, it must be hammered down against the buckle and each of the ears also "hammered down against the end of the strap, thus increasing the installation time. Mild steel is a suitable strapping material for uses in which the higher strength of stainless steel is not required, and is also cheaper than stainless steel. However, the buckles heretofore used with mild steel strapping have either been difficult or costly to make, or tend to permit the strap to slip long before the load on the strap has approached its .tensile strength. Thus, a simple buckle which encircles the strap and is either punched into the strap from the top, or deformed at the side so as to deform the strap simultaneously, does not utilize the full strengthof the strap.

Among the objects of this invention are to provide a novel pressure clamp; to provide such a clamp which permits the buckle and clamp to be made simply; to provide such a clamp which permits the full strength of the strapping to be utilized; to provide such a clamp which eliminates an unduly exposed free end of the strap; to provide such a clamp which may be applied by existing tools or by special tools; to provide a novel method for applying such a clamp; and to provide such a clamp which will be rugged and withstand abuse in use, while maintaining its clamping effectiveness.

Additional objects and the novel features of this invention will become apparent from the following description, taken in connection with the accompanying drawing, in which:

Fig. l is a side elevation of a clamp of this invention, applied to a hose attached to a ferrule or nipple;

Fig. 2 is a perspective view of a buckle or connector of the clamp ofFig. 1;

Fig. 3 is a perspective view of an alternative buckle or connector;

Fig. 4 is a side elevation, on a reduced scale, of a strap and buckle assembly, which may be utilized in forming the clamp of Fig 1;

Fig. 5 is an enlarged, fragmentary transverse section taken through the clamp of Fig. l, at the buckle or connector;

Fig. 6 is a side elevation of a previous type of toolprovided with an attachment particularly adapted to apply the clamp of this invention and shown in a'position preparatory to severance of the free end of the strap; and

Pig. 7 is a fragmentary transverse section, illustrating the use of the tool in application of tension to the clamp strap.

As illustrated in Fig. l, the clamp of the present invention may comprise a buckle B adapted to secure the ends of a strap S around a hose 9, with sufficient tension on the strap S to securely clamp the hose 9 to a nipple 10. It will be understood, of course, that the clamp may be applied in other situationssuch as those indicated previously, and also that the strap S and buckle B may be made of any desired material, such as 'mild steel, although stainless steel .or material having a lesser or greater tensile strength than mild steel may be utilized. The buckle B, as in Fig. 2, preferably has open ends, through which the strap may extend, and maybe stamped or otherwise formed, as from afiat strip. The top 11 of the buckle may be provided with a transverse ridge 12, as in Fig. 2, or as in the case of the buckle B of Fig. 3, the top 11' may be provided with a pair of transverse ridges 12', it being observed that the buckle B of .Fig. 3 is generally adapted to be utilized for the larger sizes, or strapping having a greater width or thickness and thus requiring greater strength in the buckle. The ridges '12, or 12, may be formed at spaced intervals in a strip, which may be cut into successive lengths, 'each suitable for forming a single buckle. Thus, the portion 'of the strip before and behind 'the ridge or ridges may be bent downwardly and then under, to form the sides 1'3, 13',

and the bottom flanges 14, or 14, the edges of which weld or attach the ends of the flanges 14, or.14', together to form a complete closure.

In applying the pressure clamp of Fig. l, to form the completed clamp of Fig. 5, a fixed end 15 of the strap S may be bent around so as to lie underneath the bottom flanges 14, as in Fig. 5, and more than one layer, such as an inner loop 16 and an outer loop 17, passed around the article to be clamped and through the buckle. Tension is applied to the free end 18 of the strap, by a suitable tool, such as the tool T of Fig. 6, described later. The strapping may be obtained from a continuous roll, but preferably a buckle and strap unit, as shown in Fig. 4, is utilized. In the latter, the fixed end 15 of the strap is bent .under the buckle, and two loops 16 and 17 of strapping extend through the buckle, with the free end 18 being left sufliciently long to permit the tension tool to be attached thereto.

After suflicient tension has been applied to the strap, to produce the desired clamping pressure, the free end 18 of the strap is bent upwardly against the end of the buckle top 11, and the free end of the strap then cut off at a point as closely as possible to the top of the buckle. If the severed end still extends considerably above the top of the buckle, it may be cut off closer to the buckle top by a chisel, cutters, pliers, or the like, and then filed down until flush with, or slanting downwardly from the top of the buckle to provide the strap end 19 of Fig. 5. As will be evident, the previously objectionable projecting portion is eliminated. Tests of clamps so made have shown that the full strength of the strapping can be developed by the cut-off end of the strap engaging the end of the buckle by a substantially right angle turn. While a highly satisfactory clamp can be applied in the manner described above, the additional cut-off and filing operations may be dispensed with by using a special tool, such as the tool T provided with an attachment A, as in Fig. 6, to permit the free end of the strap to be sheared flush with the top of the buckle, in a single operation.

The tension tool T shown in Fig. 6 is constructed in accordance with U. S. Patent No. 2,208,114, and includes a slide 20 adapted to be moved along a frame 21 by a fixed screw 22, the slide 20 having an angular slot 23 therein, into which the strap may be passed so as to be clamped by the serrated edges of a clamping cam 24, pivotally mounted in the slide 20 and operated by a handle 25. Screw 22 extends through a journal 26, preferably formed integrally with the frame 21 at the outer end thereof, while the screw 22 engages an interiorly threaded block 27 which may be rotated by a tension handle 28, the thrust of the handle being transferred through a ball bearing ring 29 to the frame at journal 26. A substantially V-shaped nose 30 is disposed at the front end of the frame 21, being preferably formed integrally therewith and provided with a longitudinal slot 31, open at one side for readier insertion of the strap S. In the previously normal use of the tool T, the end of nose 30 is placed against the side of a buckle and the tension handle 28 rotated to pull the free end of the strap through the buckle until the desired tension is obtained.

The nose 30 of tool T may also be provided with a cylindrical, transverse hole 32, in which a tapered cutter 33 is mounted for rotation, the cutter being adapted to be turned by a handle 34. As will be evident, the cutter 33 severs the strap S at a point spaced a greater distance from the buckle B than is desired for the present invention, so that the cutter 33, although particularly useful in installing clamps of a type previously described, is not necessary for applying the clamp of the present invention when the attachment A of Fig. 6, constructed in accordance with the copending application of Harold H. Beardsley, Serial No. 318,420, filed November 3, 1952, is mounted on the tool T.

The attachment A, as in Fig. 6, includes a frame 36 which may be constructed so as to partly encircle the nose 30 of the tool T. The frame 36 terminates at its front end in a laterally extending bar 38, to the underside of which is attached a shear plate 39 provided with a shearing edge along the front of a slot through which the strap passes, as in Fig. 7. Shear plate 39 also may be provided with an extension 41 which engages the underside of nose 30 of the tool T, and a groove 42 of Fig. 7, slanting rearwardly from the front edge and having a width greater than the buckle B. The shearing edge of the shear plate 39 may be beveled slightly, to prevent any tendency for shaving off the strap while the strap moves between the plates 38 and 39 during tensioning, while the forward edge of groove 42 may be rounded, to prevent the shear plate from cutting into the loop 17 of the strap during tensioning. Groove 42 permits the shear plate 39 to lie closer to the strap loop 17 when tension is applied to the free end 18 of the strap, as in Fig. 7, so that tension on the free end may be applied along a line more nearly tangential to loop 17, i. e., more nearly in the plane of buckle B. In applying tension, bar 38 is placed against the end of the buckle, and the free end 18 of the strap, previously clamped by cam 24 of Fig. 6, pulled by rotation of handle 28, as previously described.

The attachment A also includes a bracket 44 having upwardly extending sides, open at the front and connected at the rear by a back 45 and mounted on the top of frame 36, as by cap screws 46 and 46' which extend through flanges 47 and 47', respectively, the flanges 47 extending laterally outwardly from the forward end of each of the bracket sides and the flange 47 extending rearwardly from the back 45. The cap screws 46 also conveniently attach shear plate 39 to frame 36. Pivotally mounted between the bracket sides are a cam 48 out; pin 49, disposed at an upper forward position, and a lever 50 on a pin 51 disposed in a rear position. Lever 50 has a lateral notch 52 on its underside adjacent its preferably slanted front end 53 to provide a point 54 for engaging the end of buckle B opposite the free end of the strap, the width of lever 50 preferably being at least a substantial proportion of the width of the widest strap to be cut, while a handle 55 may be attached to cam 48 for rotating the same. When the cam handle 55 is moved rearwardly and against the bracket back 45, the rear end of cam 48 will maintain lever 58 in its normal position, so that the free end 18 of the strap may be passed through the slot between bar 38 and plate 39 and back through slot 31 in the tool nose 30 and then through slot 23 in slide 20, clamping cam 24 then wedged against the strap, and tension applied by rotating handle 28, as indicated previously. When suflicient tension has been applied, the tool is moved to bend the strap back toward the end .of buckle B, when the clamp is being applied to a pipe, girder, or the like, which is in fixed position, or the tool may be maintained in fixed position, as in a vise. and the hose or other readily movable article to which the clamp is being applied, rolled over or rotated relative to the tool, so that the free end of the strap will be bent back over to the position of Fig. 6. During such bending, the tension handle 28 is preferably rotated slightly in a reverse direction, to prevent the strap from being broken, but will not cause any tension to be lost, since the bend in the strap will take up the amount of strap released.

The tool and strap will then be in the position of Fig. 6, in which the point 54 of lever 50 has moved onto the opposite end of the buckle B. From the position of Fig. 6, the only operation needed to complete the application of the clamp is to move the handle 55 in the direction of arrow 56, i. e., outwardly, so that the force applied by lever point 54 will cause the shear blade 39 to cut through the strap to produce the sheared end 19 of Fig. 5. During the shearing operation, the end of the buckle acts as a backing member for the shear blade 39, i. e., the buckle itself forms one jaw of a cutting tool, as it were. As will be evident, when the shearing operation is concluded, the clamp is completed, and no additional operations are necessary. Thus, after removing the severed end of the strap from the tool, the operator is ready to apply the next clamp.

While the tool T of Fig. 6 is useful in applying other types of clamps, by the removal of attachment A, it may be desired to provide a tool which does not require a separate attachment and involves no unnecessary parts for operation in applying the clamp of this invention, such as the cutter 33 and handle 34 therefor of the tool T. Such a tool may be constructed in the manner disclosed in the aforesaid copending application of Harold H. Beardsley.

From the foregoing, it will be evident that the clamp and method of this invention fulfill to a marked degree the requirements and objects hereinbefore set forth. The buckles are simply and economically made, and one or more transverse ridges permit the buckles to be made of thinner material than otherwise, while still providing suflicient strength. By merely bending the free end of the strap up against the edge of the buckle top, a clamp can be produced which has the equivalent strength of a considerably more complicated clamp. Also, by providing the bent-up end of the strap with a terminal surface which is substantially flush with the upper surface of the buckle top, and is preferably inclined upwardly to the upper surface of the buckle, objectionable strap ends which project above or beyond the buckle top are avoided, but the desired strength of the clamp is still produced. Such terminal surface may be produced by cutting ofi the free end of the strap above the buckle by the tool, and then severing the strap closer to the tool, and additionally severing material from the strap end, as by filing. Or, a special tool may be utilized to shear the end of the strap flush with the buckle top, or inclined upwardly toward the top surface of the buckle. In either event, the operations involved in applying the clamp are relatively simple and can be carried out with relative speed and facility.

Although one embodiment of this invention has been described with particularity, with variations in the buckle, and alternative embodiments of the method of this invention have been described, it will be understood that other embodiments may exist and variations made therein, all without departing from the spirit and scope of this invention.

What is claimed is:

l. A pressure clamp which comprises the combination of a generally hollow buckle having a top wall, side walls, and bottom wall flanges turned inwardly from said side walls, said top wall having a front edge and a rear edge and an upper surface, said inturned flanges having front edges and rear edges corresponding to the front and rear edges of said top wall, and a strap having an inner and an outer end, the inner end of said strap being bent over the rear edges of said inturned bottom wall flanges and forming a hook securing said inner end of said strap to said buckle, the strap passing through said hollow buckle at least once between said top wall and said bottom wall flanges and forming a looped portion intermediate the inner and outer ends of said strap, the outer end of said strap being bent up against said front edge of said buckle top wall and cut off flush with said upper surface of said buckle top wall, said hook portion at the inner end of said strap secured to said buckle and said bent-up portion at the outer end of said strap abutting said front edge of said buckle maintaining the looped portion of said strap under substantial tension without requiring indentations in said buckle crimping said strap.

2. A pressure clamp constructed according to claim 1 in which the cut surface of the bent-up portion at the outer end of said strap is inclined upwardly toward the upper surface of the top wall of said buckle.

3. A pressure clamp constructed according to claim 1 in which the top wall of said buckle is provided with at least one raised rib transverse to said strap for strengthening said top wall.

4. A pressure clamp constructed according to claim 1 in which said strap passes three times through said hollow buckle and the portion of said strap intermediate its inner and outer ends forms two loops, one loop being superimposed on the other.

References Cited in the file of this patent UNITED STATES PATENTS 1,393,791 Kimball et al. Oct. 18, 1921 1,786,107 de Vulitch Dec. 23, 1930 2,046,634 Johnson July 7, 1936 2,084,063 Rebichon et al. June 15, 1937 2,312,575 McKee Mar. 2, 1943 FOREIGN PATENTS 482,787 Great Britain Apr. 5, 1938

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