US3754303A - High compression band clamp - Google Patents

Abstract

A band clamp for high compression fastening of a hose or other flexible tubing, making use of a metal band adapted to encircle the tubing once or twice from an inner band end fixed to the base of a one-piece buckle and to be drawn through and interlocked with the buckle under high tension, is provided with a buckle structure enabling the band to be tensioned and locked in place by any of the conventional lock-up procedures. The buckle is made so rigid that the band can be tightened by a tool gripping its free end and thrusting against the buckle, and then locked by being bent up against and cut off over the front edge of the top wall of the buckle; yet that wall is made with a deformable thinned central section which, when the band has been similarly tightened, can be punched to force it and underlying portions of the band into an interlocking depressed configuration, whereupon the free end of the band may be broken off along said front edge.

Description

ilnited States Patent [191 Pollock [451 Aug. 28, 1973 HIGH COMPRESSION BAND CLAMP [75] Inventor: Leonard J. Pollock, Oceanside, NY.

[73] Assignee: Ideal Corporation, Brooklyn, NY. 221 Filed: Mar. 30, 1912 [21] Appl. No.: 239,550

[52] US. Cl. 24/23 W [51] Int. Cl B65d 63/06 [58] Field ofSearch 24/20 W, 20 TI, 20 R,

[56] References Cited UNITED STATES PATENTS Primary Examiner-Donald A. Griffin Attorney-Albert C. Johnston [57] ABSTRACT A band clamp for high compression fastening of a hose or other flexible tubing, making use of a metal band adapted to encircle the tubing once or twice from an inner band end fixed to the base of a one-piece buckle and to be drawn through and interlocked with the buckle under high tension, is provided with a buckle structure enabling the band to be tensioned and locked in place by any of the conventional lock-up procedures. The buckle is made so rigid that the band can be tight enecl by a tool gripping its free end and thrusting against the buckle, and then locked by being bent up against and cut off over the front edge of the top wall of the buckle; yet that wall is made with a deformable thinned central section which, when the band has been similarly tightened, can be punched to force it and underlyingrportions of the band into an interlocking depressed configuration, whereupon the free end of the band may be broken off along said front edge.

7 Claims, 6 Drawing Figures HIGH COMPRESSION BAND CLAMP This invention relates to a new and improved band clamp for fastening a hose, plastic pipe or other flexible tubing under high compression and relates more particularly to a new buckle structure for such a clamp.

By a band clamp is meant a clamp making use of a one-piece buckle and of a band comprising a length of metal strapping which is adapted to be fixed at one end to the bottom of the buckle and thence to encircle the tubing in one or two convolutions passed through the buckle, and which clamps the tubing, as upon a tubular fitting or a pipe end, by being pulled tight by a tool thrusting against the buckle and then interlocked with a top part of the buckle under high tension, whereupon the free end portion, or tail, of the band may be severed.

In one well known type of band clamp, e.g., see US. Pat. No. 2,746,107, the buckle is made so rigid and the band sufficiently strong that the band can be pulled to high tension by an appropriate tool and then locked in place by being bent up against and sheared off over the front edge of the top wall of the buckle, thus leaving a strong upbent lip butting against that edge to hold the band tension.

In a second well known type of band clamp, e.g., see U.S. Pat. No. 2,3l2,575, the buckle is made ofa piece of pliant metal so that, after the band has been tightened by a suitable tool thrusting against the buckle, the top wall of the buckle may be locally punched inwardly, as by means of a blunt nosed punch struck by a mallet, so as to deform a portion of the top wall and underlying portions of the band into an intemesting, interlocked configuration. Then the free end portion, or tail, of the band is broken off by working it up and down at the front edge of the top wall of the buckle.

The existing band clamps of each of those types are suitable only for their own special manner of being locked in place after the tightening of the band, and each type requires its own special tool for efficient installation of the clamps. The tool suitable for one type is not suitable for the other.

Moreover, the existing clamps of each type have, relative to those of the other type, advantages for some uses and disadvantages for others, so that where a variety of uses is to be served by band clamps it is necessary to provide more than one type of the clamps, as well as the related tools, in order to serve each use to the best available advantage.

For instance, although commercial punch-locked clamps are often more economical to use, the front edge of their buckle tends to be displaced upwardly by the punching operation and may be lifted further by the working of the band tail to break it off, with a resulting unsightly appearance and a tendency to reduce the tension applied to the band. The lifted front edge sometimes is hammered down to improve the appearance, but this tends further to reduce tension by disturbing the lockup. Moreover, because of the shock blow of the punch locking operation, these clamps are quite disadvantageous for certain uses such as for clamping hose under high compression on a clay pipe or glass pipe or thin-walled metal pipe (tubing), or on tubular fittings that protrude as preassembled parts of a machine or other structure; the pipe or fitting in such cases can easily be damaged by the punch blow required for locking the clamp.

It is an object of the present invention to provide a band clamp which will fulfill advantageously the requirements of any of a variety of uses and which can be installed and locked effectively under high tension by any of the conventional lockup procedures. Thus, a given clamp according to the invention can be installed efficiently with the aid of any available tool that is suitable for the use being made of it, and a single clamp type serves advantageously all the uses of the two common types of band clamps.

A band clamp according to the present invention may be similar to conventional band clamps in that it comprises a length of metal strapping constituting the band and a fitting, one-piece buckle of substantially rectangular hollow shape defined by a top wall, opposite side walls and a bottom wall. Also, the bottom wall may be formed by bottom flanges inturned from the side walls. According to this invention, however, the buckle walls are made with a thickness and rigidity rendering the buckle substantially non-deformable by the maximum force to be applied to it for tensioning the band, yet the top wall of the buckle is made to comprise a wall section of substantially reduced thickness which is deformable by a punching operation so that this thinned wall section and underlying portions of the band may be punched into an interlocking depressed configuration without distortion of other portions of the buckle.

The buckle may be composed of a piece of suitably thick and rigid sheet metal such, for example, as a cold rolled and annealed type 20l stainless steel or MS] 1055 carbon steel, having a thickness of about .045 to .050 inch. The steel piece is bent into the required shape after a central portion of the top wall part of it, constituting the deformable top wall section of the buckle, has been thinned to the extent required. The

thinning is effected advantageously by a squeezing of the material that brings it to a reduced thickness amounting, for example, to approximately to percent of the original thickness.

While it is feasible to form the thinned top wall sectibn of the buckle by squeezing a central portion of the metal piece, or blank, in a coining operation, with the blank completely confined so as to prevent distortion of it, this wall section according to a further feature of the invention is a thinned portion of the piece lying between two slots formed in the top wall. These slots provide a manufacturing advantage, in that they may be formed by punching through the metal piece in a progressive die press operation by which, after their formation, the metal between them can flow laterally into the space of the slots as it is squeezed to the reduced thickness. The slots, moreover, also provide a distinct functional advantage, for by freeing two sides of the thinned wall section from connection with the top wall of the buckle they enable deeper and easily controlled penetration of this section into interlocking depression with underlying portions of the band when the clamp is installed by the punch-locking method.

It has further been found advantageous to form the junctions between the ends of the thinned wall section and other portions of the top wall of the buckle with a concave curvature having a radius of at least .005 inch. This feature aids in preventing the thinned section from being sheared from the top wall under a heavy blow in a punch locking operation.

The foregoing and other objects, features and advantages of the invention will be further apparent from the following detailed description and the accompanying drawing of an illustrative embodiment thereof.

In the drawing,

FIG. 1 is a perspective view of the new band clamp in a condition of pre-assembly for convenient use;

FIG. 2 is a schematic view of steps of the progressive formation of a strip of sheet steel into blanks ready to be shaped into the buckle of the clamp;

FIG. 3 is a perspective view of the finished buckle;

FIG. 4 is a transverse cross section through the buckle taken along line 4-4 of FIG. 5;

FIG. 5 is a schematic fragmentary longitudinal cross section showing the clamp as it is locked under tension on a hose by the punch method; and

FIG. 6 is a schematic fragmentary longitudinal cross section showing the clamp as it is locked under tension on a hose by a bent-up lip of the band.

The band clamp of this invention as shown in FIG. 1 is composed of aband 10 and amating buckle 14.

Theband 10 comprises a suitable length of a strong, pliant metal stripping material, such as a cold rolled and annealed steel in strip form. Its length is sufficient to provide inner andouter end portions 11 and 13 for use in fastening the clamp and to form acoil 12, which preferably is a doubly wrapped coil having twoconvolutions 12a and 12b for encircling the hose or other flexible tubing that is to be clamped in its use. A double wrap of the band about the tubing enables a substantial increase of the clamping pressure attainable by a given tension on the band. When the band is made of a metal, such as galvanized steel, which would exhibit a high coefficient of friction between contacting layers of it, it is beneficial to use for a doubly wrapped band a metal strip having its surfaces treated with an anti-friction composition, such, for example, as a lubricating wax or a liquid Teflon (Vydac). This limits the friction between the convolutions of the band so that it will not objectionably limit the tension that can be applied effectively for tightening the band in place on a hose.

Thebuckle 14 comprises a relatively rigid one-piece body having a substantially rectangular hollow shape defined by atop wall 16, oppositeupright side walls 17 and 18 and a bottom wall constituted bybottom flanges 19 and 20. The buckle preferably is curved longitudinally to a radius approximating that of the contour of the hose or other tubing to be fastened in the use of the clamp.

The flanges l9 and 20 are inturned from the side walls so as to lie in a common plane and substantially parallel to the top wall. They need not meet but may define aslit 21 between their inner edges along the Iongitudinal axis of the buckle. Midway along this slit a portion of the inner edge of each of the flanges is cut away arcuately so as to provide in the bottom wall acentral opening 22 of substantially circular outline in alignment with a specially formed, deformable thinnedcentral section 24 of the top wall.

The buckle is made from a unitary piece of sheet metal, such as a piece of cold rolled and annealed stainless steel or galvanized carbon steel of the nature described above, which when bent into the required shape gives the buckle walls a thickness and rigidity ensuring that the buckle will not be deformed objectionably by either the tensioning of the band or the manipulation of thetail 13 of the tensioned band, irrespective of the kind of tool and of the lock-up procedure used for installing the clamp. Thethinned section 24, however, is made with a substantially reduced thickness amounting, typically, to about to percent of the thickness of the original metal piece, so that this section is readily deformable for lock-up of the tensioned band by a punch blow without distortion of the other portions of the buckle walls.

Thethinned section 24 is made by squeezing a central portion of thetop wall 16 to the required reduced thickness. The portion so squeezed is the central portion of asegment 25 of the top wall lying between two parallel transversely directedslots 26 and 27 formed inwall 16. These slots have a double function in that they enable the metal displaced by the squeezing operation to flow laterally into the space of the slots, so that the top wall is not distorted by a simple die squeezing operation, and they enable thethinned section 24 to be deformed deeply by a punch blow without causing objectionable deformation or distortion of the buckle.

As illustrated schematically in FIG. 2, each metal piece, or blank, BL which is to be formed into the hollow rectangular shape of thebuckle 14 may be preformed with theslots 26 and 27 and the requiredthinned section 24 between them, and with edges cut away as at 22a and 22b to define the bottom opening 22, by subjecting a suitably thick andwide strip 30 of the sheet metal to a progressive die operation. In that operation a completely preformed blank is produced from the metal strip in each stroke of the press containing the forming dies. For instance, in each stroke of the press thestrip 30 may be subjected to operations at positions A, B, C and D, while between strokes the strip is advanced through the press by a distance corresponding to the length of the blank. At position A ahole 32 is punched in the strip. Atposition B slots 26 and 27 are punched in the strip midway betweensuccessive holes 32, leavingwall segment 25 between the slots. Atposition C segment 25 is squeezed to form the deformable thinnedsection 24. The squeezing die is made to form the fillets or junctions, as at 24a (FIG. 4), between each thinnedsection 24 and the unsqueezed ends ofsegment 25 with a concave curvature having a radius of at least .005 inches. At position D the preformed blank is sheared off by acut 34 extending transversely of the strip through the center line of ahole 32, so that opposite end edges of the resulting blank BL contain therecesses 22a and 22b.

The blank BL is now ready to be formed into the shape of thebuckle 14, as by bending it first to an inverted U form having thetop wall 16 flanked by depending legs and then bending lower portions of these legs inwardly to form thebottom flanges 19 and 20. The remaining upper portions of the legs then constitute thebuckle side walls 17 and 18. By utilizing suitably curved dies for the bending operations, the buckle is given the longitudinal curvature desired for fitting approximately the contour of the size of hose for which the clamp is designed.

When the buckle is made from a sheet steel that has work hardening qualities, such, for example, as a stainless steel of the A181 300 series, the bending of the blank into the required shape of the buckle adds hardness and rigidity to the bends or corner portions of the finished buckle. This is advantageous since it adds to the strength of the buckle. On the other hand, the squeezing ofsegment 25 to form the thinnedsection 24 causes a hardening of this section which tends to make it less amenable to deformation by a punch blow. While the extent of this hardening is ordinarily not sufficient to detract from the effectiveness of the clamp, the manufacture of the buckle may be modified if desired so as to secure the advantage of work hardening at the bends of the buckle yet to provide the natural ductility of the metal in the thinnedsection 24. To this end, after the formation of each blank in the manner described but before the bending of it into the shape of the buckle, the blank is annealed so as to eliminate the work hardening produced by the squeezing operation. Then the annealed blank in cooled condition is bent into the shape of the buckle as described above.

As a result, according to this additional feature of the invention, when the buckle is made from workhardenable steel the squeezed, thinnedsection 24 is in annealed condition, so is relatively ductile, while the corner portions of the buckle are in a work-hardened state produced by the bending of the blank.

ln assembling the band with thebuckle 14 to provide a complete clamp, one end of the band is first passed through the buckle and bent back over itself upon the bottom wall of the buckle, thus forming a hook having a free end or tail ll engaged around and underneath that wall. The remainder of the band may then be coiled to a size slightly greater than the hose size, or wrapped directly about the hose, and passed through the buckle, in either one or two convolutions, depending upon whether the clamp is made for single or double wrap application. A free outer end portion, or tail, 13 of the band then protrudes tangentially from the buckle for engagement by a suitable tool when, with the clamp in position for use on a hose or like tubing, the band is to be forcibly drawn further through the buckle so as to contract it upon the hose under high tension.

By virtue of the rigidity given to the walls of the buckle by the metal piece formed into them, the buckle is substantially non-deformable by the maximum force applicable to tension the band, irrespective of which one of the common kinds of band clamp tools is used to tension the band by grasping the tail l3 and drawing it forward while thrusting against the buckle. Yet by virtue of thetop wall section 24 being made with a substantially reduced thickness so as to be deformed by a punch blow, that thinned section and underlying portions of the band can be punched into an interlocking depressed configuration without incurring objectionable distortion of other portions of the buckle.

FIG. 5 schematically illustrates the condition of the clamp when it is being instailed by the punch locking method. The clamp has been positioned about the end of a hose H fitted on a rigid tube T, such as a pipe end or a tubular fitting, and theband tail 13 has been drawn through the buckle M to high tension by a tool grasping it and thrusting against the buckle, theband convolutions 12a and 12b thus having been contracted extremely tightly upon the hose so as to clamp the hose upon the tube '1 under high compression. At this stage, while the tensioning tool is still holding the band taut, a blunt-ncsed punch P is positioned centrally on the deformable thinnedsection 24 of the buckle wall M and is given a strong blow by a mallet. The punch under this blow depressessection 24 andunderlying portions 10a, 10b and 10c of the band into an internesting depressed configuration which extends deeply into opening 22 in the bottom wall of the buckle and so strongly interlocks the band and the relatively rigid buckle that the band is permanently locked in place under the high tension imparted to it by the tensioning too]. Then thetailpiece 13 may be worked up and down by swinging the tool, or by hand if desired, until it is broken off at approximately a bend line 1130 along the front edge 16a of the top wall of the buckle.

The clamp according to the invention is also excellently suited for being locked under high tension by a bent-up lip of the free end portion or tail E3 of the band, as illustrated schematically in FIG. 6. For this manner of lock-up, when the band has been drawn to high tension by a tool grasping its tail l3 and thrusting against thebuckle 14, the tool is swung upward so as to bend the tail up against the front edge 16a of the top wall of the buckle. Then the tail may be cut off along the top of that edge by a shearing device operated by further manipulation of the tool, for example as described in U.S. Pat. No. 2,746,324, so as to leave a bent-uplip 13b of the band butting against the buckle and thus locking the tightened band under the high tension imparted to it by the tool. This manner of lockup is preferred for uses of the clamp in which the strong blow of the punch locking procedure would tend to damage the tube T upon which the hose H or similar flexible tubing is to be installed, such as for uses of the clamp to fasten hose on clay or glass pipe, on thinwalled metal tubing, or on a tubular fitting preassembled in cantilevered relation to a machine or other structure.

While any of the several forms of tools commonly used for tensioning and locking up band clamps may be used for installation of the new band clamp, a single tool may be provided for the tensioning of the band and may be fitted with separate adapters enabling the interlocking of the tensioned band with the buckle to be effected by either the punch method or the bent-up lip method.

The buckle of the new clamp effectively overcomes the tendency of the buckles of common forms of punch-locked band clamps to distort or lift upwardly at the front edge under the impact of the punch blow, and to lift further when the free tail is worked up and down in order to break it off. Thus the high tension initially applied to the band is retained to a greater degree, and no hammering down of the buckle is needed to improve the appearance of the installed clamp. The greater thickness and strength of the buckle walls enables the buckle to accept stronger band tensioning forces applied through the tensioning tool, and enables a greater depth of punching to be effective for locking the band under tension. Further, by virtue of the greater strength of the buckle body the bottom flanges of the buckle are more resistant to spreading apart under the force of the punch blow than is the case with the common fonns of punch-locked band clamps.

Accordingly, the buckle of a band clamp according to the present invention can sustain, without undergoing distortion, a band tension as much as 18 percent greater than that sustainable by the buckles of common forms of punch-locked band clamps, and it will retain the initial high tension to a considerably greater extent than the latter after the tensioned band has been punch-locked and the tail of the band broken off. Moreover, when the clamp is locked up by the bent-up lip method it will sustain a tension at least as high as .and usually somewhat higher than that sustainable by the common forms of band clamps made for being locked up by that method.

It willbe understood that the invention can be carried out in ways differing from those particularly described herein and illustrated in the drawing, while still utilizing the teachings of the invention which are intended to be defined by the appended claims.

What is claimed is:

1. A'clamp for fastening a hose or other flexible tubing under high compression, comprising a one-piece buckle of substantially rectangular hollow shape defined by a top wall, opposite side walls and a bottom wall and a band comprising a length of metal strapping adapted to have one end thereof bent back over itself upon said bottom wall, thence to encircle said tubing and pass through said buckle in one or two convolutions, then to be pulled to high tension by a tool gripping its free end and thrusting against the buckle and then to be interlocked with said top wall, after which said free end may be severed, characterized in that said buckle walls have a thickness and rigidity rendering the buckle non-deformable by the maximum force applicable to tension said band yet said top wall, which is composed of a single, unitary panel, comprises inside the margins of said panel a section thereof of substantially reduced thickness which is deformable by a punching operation so that said section and portions of said band underlying it may be punched into an interlocking depressed configuration without distortion of other portions of said buckle.

2. A clamp according to claim 1, said buckle being composed of a piece of sheet metal bent into said shape and said deformable section being a thinned central portion of said top wall.

3. A clamp according to claim I, said buckle being composed ofa piece of sheet metal bent into said shape and said deformable section being a thinned portion of said top wall lying between slots formed therein.

4. A clamp according to claim 1, said buckle being composed of a piece of sheet steel about .045 to .050 inch thick bent into said shape and said deformable section being a central portion of said top wall lying between substantially parallel slots formed therein and squeezed to approximately 55 to 65 percent of the thickness of said piece.

5. A clamp according to claim 4, the junctions between the ends of said squeezed portion and other portions of said top wall being curved concavely on a radius of at least .005 inch.

6. A clamp according to claim 4, said steel being a work-hardening steel, said squeezed portion being annealed and the corner portions of said buckle being in a work-hardened state produced by the bends of said piece.

7. A clamp according to claim 1, said buckle being composed of a piece of sheet metal bent into said shape and having said walls thereof curved longitudinally to conform substantially to the contour of said tubing,

tion.

Claims (7)

1. A clamp for fastening a hose or other flexible tubing under high compression, comprising a one-piece buckle of substantially rectangular hollow shape defined by a top wall, opposite side walls and a bottom wall and a band comprising a length of metal strapping adapted to have one end thereof bent back over itself upon said bottom wall, thence to encircle said tubing and pass through said buckle in one or two convolutions, then to be pulled to high tension by a tool gripping its free end and thrusting against the buckle and then to be interlocked with said top wall, after which said free end may be severed, characterized in that said buckle walls have a thickness and rigidity rendering the buckle non-deformable by the maximum force applicable to tension said band yet said top wall, which is composed of a single, unitary panel, comprises inside the margins of said panel a section thereof of substantially reduced thickness which is defOrmable by a punching operation so that said section and portions of said band underlying it may be punched into an interlocking depressed configuration without distortion of other portions of said buckle.

2. A clamp according to claim 1, said buckle being composed of a piece of sheet metal bent into said shape and said deformable section being a thinned central portion of said top wall.

3. A clamp according to claim 1, said buckle being composed of a piece of sheet metal bent into said shape and said deformable section being a thinned portion of said top wall lying between slots formed therein.

4. A clamp according to claim 1, said buckle being composed of a piece of sheet steel about .045 to .050 inch thick bent into said shape and said deformable section being a central portion of said top wall lying between substantially parallel slots formed therein and squeezed to approximately 55 to 65 percent of the thickness of said piece.

5. A clamp according to claim 4, the junctions between the ends of said squeezed portion and other portions of said top wall being curved concavely on a radius of at least .005 inch.

6. A clamp according to claim 4, said steel being a work-hardening steel, said squeezed portion being annealed and the corner portions of said buckle being in a work-hardened state produced by the bends of said piece.

7. A clamp according to claim 1, said buckle being composed of a piece of sheet metal bent into said shape and having said walls thereof curved longitudinally to conform substantially to the contour of said tubing, said deformable section being a squeezed central portion of said top wall lying between substantially parallel slots punched therethrough, said bottom wall comprising flanges inturned from said side walls and having in their confronting edges punched out areas defining a bottom opening aligned with said deformable wall section.

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