GB2092036A

GB2092036A - Tube bender construction

Info

Publication number: GB2092036A
Application number: GB8201597A
Authority: GB
Original assignee: Imperial Clevite Inc
Current assignee: Clevite Industries Inc
Priority date: 1981-01-30
Filing date: 1982-01-20
Publication date: 1982-08-11
Also published as: GB2146275A; FR2498953A1; FR2498953B1; DE3201770A1; CA1180259A; GB2092036B; GB8412430D0; GB2146275B

Abstract

A tube bender construction (10) for manual operation in bending a tube (T). The tube benders include a mandrel (11) defining a bending groove (12) into which the tube is urged by a forming member (13) mounted to the mandrel to swing about a bending axis of the bending groove. The tube to be bent is held against longitudinal movement during the bending operation. Movement of the forming member about the bending axis is effected by manipulation of a pair of handles 17, 18 the shafts and hand-grips 20, 32 being so disposed that the handles can be swung up to and past each other, while both hand-grips are located in the plane of bending. <IMAGE>

Description

SPECIFICATION Tube bender construction BACKGROUND OF THE INVENTION Field of the Invention This invention relates to tube benders and in particular to manually operable tube benders wherein a forming member is swung about a bending axis by means of a handle associated therewith and a handle mounted to the mandrel.

Description of the Background Art Manually operable tube benders are well known in the art. One improved form of such tube bender is illustrated in U. S. Letters Patent 2,796,785 of Howard L. Philippe. As shown therein, a shoe forming member is provided with a handle. The shoe is swingably mounted to a mandrel for pivotal movement about a bending axis. A second handle is connected to the mandrel. A hook is swingably mounted on the second handle for engaging the tube at a point adjacent the bend start point of a groove in the periphery of the mandrel into which the tube is urged in the bending operation.

Further improved tube benders are illustrated in U. S. Patent 2,887,917 and 3,926,028 of the inventor herein. In U. S.

Patent 2,887,917, a tube bender is illustrated wherein the handle connected to the mandrel is provided with an offset and improved scale means are provided on the mandrel for indicating the extent of the formed bend.

In Kowal U. S. Patent 3,926,028, the tube bender is provided with a vise mounting portion in lieu of the handle secured to the mandrel. In one form, the hook is formed integrally with the male clamp portion, and in a second form, the hook is pivotally mounted thereon.

In U. S. Letters Patent 3,750,447 of the inventor herein and William R. Saddler, a further improved tube bender is illustrated having fixed hook means with a cutout space being provided in confrontation to the hook to permit facilitated installation of the tube to be bent into the tool, notwithstanding the fixed relationship of the hook to the mandrel. The tube bender has a shoe member swingably mounted to the mandrel and is disclosed in combination with a novel tube-retaining hook structure.

Further, manually operable tube benders having a forming member mounted to swing about a bend axis of a forming wheel are well known in the art. Illustratively, in said above discussed U. S. Letters Patent 2,796,785 of Howard L. Philippe, a manually operable tube bender is shown to have a forming member swingably mounted to the form wheel by means of a link. The forming member comprises a shoe having a groove engaging the outer surface of the tube to be bent and defining the force transfer surface between the shoe and tube. The shoe is pivotally connected to the link by a pivot having a fixed radial distance from the pivot of the link to the form wheel. The form wheel groove has a U-shaped configuration and the groove of the shoe has an arcuate extent of less than 1 80' for limiting undesirable flattening deformation of the tube in the bending operation.

Leonard J. Kowal, in said U. S. Letters Patent 2,887,917, shows a tube bender having a bending shoe swingably mounted to the mandrel with the mandrel having an improved scale means thereon for use in indicating the extent of the bend produced.

In said U. S. Letters Patent 3,926,028 of Leonard J. Kowal, another form of manually operable tube bender is illustrated.

SUMMARY OF THE INVENTION The present invention comprehends an improved manually operable tube bender construction having improved handle means wherein the gripping portions of the handles associated with the forming member and mandrel, respectively, are arranged so as to effectively avoid formation of force couples tending to twist the tool during the bending operation. More specifically, the invention comprehends the provision of such a handle construction wherein the gripping portions are disposed at or adjacent a common plane defined by the plane of the root of the bending groove of the mandrel. At least one of the handles is provided with an angularly extending portion for permitting the other handle to pass through the aligned relationship of the gripping portions in effecting large angle bends.

The handle connected to the mandrel may be mounted thereto by means of a unitarily integral extension of the mandrel which further defines means for mounting of the tool in a vise or the like. The mounting structure defines a first portion forming a socket for receiving the end of the mandrel mounted handle and means may be provided for removably securing that handle thereto.

The vise mounting portion is preferably formed without openings or recesses therein so as to provide a strong support when clamped in a vise or the like.

The hook may be swingably mounted to the mandrel by a portion of the mounting means intermediate the portion defining the handle and vise mounting means.

In the illustrated embodiment, the mandrel further defines a unitarily integral extension forming a rectilinear extension of the bending groove extending away from the bend start point of the groove to adjacent the hook means. The hook is arranged to clamp the tube to the mandrel extension in the extension of the bending groove for improved retention of the tube against longitudinal movement during the bending operation.

The portion-of the mandrel defining the groove extension may further comprise a portion of the mounting means so that the entire mandrel mounting means and tube clamp surface may comprise a one-piece integral element.

The hook in the illustrated embodiment is provided with an arcuate pressure-applying clamp surface for urging the tube against the extended tube support with a force resulting from the swinging of the hook.

In the illustrated embodiment, the handle construction more specifically includes a first handle connected to the forming member and having a distal end defining a first gripping portion at said bending plane, and a second handle having a connecting portion connected to the mandrel and extending therefrom away from the bending plane and defining a second gripping portion connected to the distal end of the connecting portion and extending therefrom toward the bending plane, the second gripping portions being disposed at a distance from the bending axis a distance greater than the spacing of the first gripping portion therefrom, whereby the first gripping portion may be swung about the bending axis to adjacent the second gripping portion free of interference between the user's hands on the gripping portions.

In the illustrated embodiment, the tube support co-operating with the clamping hook is defined by a portion of the mandrel defining a rectilinear groove extending away from the bending groove at the bend start point to adjacent the means for holding the tube for receiving a portion of the tube to be bent, the means for holding the tube comprising means for clamping the tube portion to the groove defining means.

In the illustrated embodiment, the handle and vise mounting means is defined by means extending from the mandrel and defining first and second mounting portions, the first mounting portion being arranged to have the second handle connected thereto for use in effecting a tube bending operation as an incident of manipulation of the two handles, and the second mounting portion being arranged to be mounted in a vise for use in effecting tube bending operations as an incident of movement of the first handle while the mandrel is fixedly held by the vise.

The present invention further comprehends an improved manually operable tube bender construction wherein the tube to be bent is held against longitudinal and rotational movement during the bending operation by an improved holding means.

More specifically, the invention comprehends the provision of means for clamping the tube adjustably against a support to hold the tube against such longitudinal displacement.

In the illustrated embodiment, the clamping means includes a hook swingably mounted to the mandrel of the bending tool so as to clamp the tube positioned on the support.

The hook is swingably mounted to the mandrel by means of a pin which is transaxially adjustable by an adjusting means to provide the desired clamping force.

More specifically, the pivot pin is eccentrically mounted to an adjustment cylinder which, in turn, is rotatively mounted in the mandrel so as to cause the pin to be moved selectively toward and from the clamping space as an incident of rotation of the mounting cylinder.

In the illustrated embodiment, a pair of mounting cylinders are provided at opposite ends of the pin for improved support of the pin in the adjustable clamping function.

Means may be provided for locking the adjusting means in the adjusted position whereby the hook is swingable about a fixed adjusted axis in the further use of the bending tool.

The adjustment of the hook may be used to provide variable clamping force corresponding to the type of tubing being bent. Alternatively, the adjustment of the hook may be utilized to take up wear of the hook to assure a desired clamping action when the hook is swung into engagement with the tube carried on the support.

Still further, the present invention comprehends an improved tube bender construction having means for adjustably mounting the forming member to the form wheel so as to permit maintained accurate disposition of the forming member relative to the bending groove of the form wheel, notwithstanding wear on the components of the tube bender and permitting desired force transfer engagement between the forming member and the tube to be bent, notwithstanding variations in the diameter of the tube to be bent.

Thus, the present invention provides a novel means for accommodating a range of different tube sizes, permitting the use of metric and conventional English dimension tubing with similar efficacy in effecting the bending. Thus, the invention eliminates the need for the provision of different configuration forming member elements in utilization of the tube bender alternatively with such different dimensional tubing.

The invention comprehends the provision of means for adjusting the disposition of the forming member relative to the bending groove of the form wheel by means of adjustable means interconnecting the forming member to the member swingably mounting the forming member to the form wheel.

In the illustrated embodiment, the adjusting means comprises eccentric means for facilitated adjustment of the forming member toward and from the peripheral edge of the forming wheel defining the bending groove.

The invention further comprehends the provision of positioning means for positioning the connecting element mounting the forming member to the form wheel in a bend-start position for correspondingly positioning the forming member in the bend-start position during the adjustment of the positioning thereof relative to the form wheel.

The form wheel may be provided with an adjustable scale for use illustratively where the adjustment of the positioning of the forming member is other than radially toward the tube bend axis about which the forming member swings.

The invention further comprehends the provision of an improved force transfer surface configuration of the forming member so as to effectively minimize stress concentration and deformation of the tubing being bent.

More specifically, the invention comprehends the provision of a concave force transfer surface on the forming member arranged to engage the portion of the tube extending outwardly from the bend groove of the form wheel at transversely opposite portions thereof spaced adjacent the peripheral edge of the form wheel and having a limited outward extent.

In the illustrated embodiment, the portion of the tube engaged by the force transfer surface of the forming member is angularly spaced from a plane through the cross-sectional center of the tube perpendicular to a radius through the center of the bend axis at least approximately 1 5'.

In the illustrated embodiment, the extent of the surface of the tube engaged by the forming member away from the plane through the cross-sectional center of the tube perpendicular to a radius through the center of the bend axis is of no greater than approximately 45".

The invention comprehends that the force transfer surface of the forming member be selectively rectilinear in transverse cross section, or rounded as desired.

The invention comprehends that the bight portion of the concave tube-engaging surface be arranged to have clearance with the radially outermost portion of the tube between the side portions engaged by the side surface portions of the tube-engaging surface.

In one form, the bight portion is trapezoidal in transverse cross section, and in another illustrated form, the bight portion is rounded.

The invention comprehends the provision of the novel force transfer surface of the forming member both in the form of the forming member wherein the force transfer surface is defined by one or more rollers, as well as in the shoe form of such forming member wherein the force transfer surface is defined by a groove formed in a shoe element, such as disclosed in the above discussed background art U.S. patents.

Where the force transfer surface is defined by a roller, a second roller may be provided spaced from the first roller for engaging the tube at a point radially outwardly of the peripheral edge of the form wheel.

The tube-engaging surface of the second roller may be defined by a surface having the force transfer surface portions and clearance bight portion as discussed above, as well as a surface of any conventional configuration. The provision of the means for adjusting the disposition of the forming member relative to the peripheral edge of the form wheel permits the maintenance of the force transfer surface engagement with the tube in the desired angularity range, as discussed above, notwithstanding wear of the tube bender components and the provision of different diameter tubing to be bent, as discussed above.

Thus, the tube bender construction of the present invention is extremely simple and economical while yet providing the highly improved features discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein: Figure 1 is an elevation of a tube bender embodying the invention; Figure 2 is a fragmentary side elevation thereof with the forming member shown in a 90 bend position in broken lines; Figure 3 is a fragmentary rear elevation thereof; Figure 4 is an elevation similar to that of Fig. 1 but illustrating the arrangement of the tube bender when arranged for manually bending a tube held in the hook thereof; Figure 5 is a fragmentary elevation with portions broken away for illustrating in greater detail the tube support portion of the tube clamping means; Figure 6 is an elevation illustrating the mounting of the tube bender in a vise;; Figure 7 is a fragmentary vertical section taken substantially along the line 7-7 of Fig.

6; Figure 8 is a fragmentary side elevation with portions broken away for facilitating illustration of the holding member adjusting means; Figure 9 is a fragmentary transverse section taken substantially along the line 9-9 of Fig.

8 with the tube holding member shown in released position in broken lines; Figure 10 is a transverse section similar to that of Fig. 9 but illustrating a modified form of tube holding member providing a wedging action in the clamping of the tube; Figure Ii is a fragmentary side elevation thereof illustrating, in broken lines, an adjusted position of the forming member; Figure 12 is a fragmentary transverse sec tion taken substantially along the line 12-12 of Fig. 11; Figure 13 is an elevation of the eccentric forming member adjusting means pin; Figure 14 is a transverse section illustrating in greater detail the improved force transfer surface configuration of the forming member; and Figure 15 is a transverse section illustrating another form of force transfer surface configuration embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODI MENTS In the exemplary embodiment of the invention as disclosed in Figs. 1-9 of the drawing, a manually operable tube bender generally designated 10 is shown to include a mandrel 11 defining an annular peripheral bending groove 12. A tube to be bent T is bent into the forming groove by a forming member 13 which is swung about a bending axis 14 of the groove 12 by its connection to the mandrel through a link 15. The tube to be bent is held against longitudinal movement during the bending operation by a holding means generally designated 16.

Movement of the forming member 13 about axis 14 is effected by suitable manipulation of a pair of handles 17 and 18 connected respectively to the forming member 13 and mandrel 11.

The invention comprehends a novel arrangement of handles 17 and 18 to permit facilitated bend formation. More specifically, as illustrated in Fig. 4, the root of the mandrel bending groove 12 defines a plane 19. Handle 17 defines at its distal end a gripping portion 20 which, as shown in Fig. 4, is disposed at the bending plane 19. In the illustrated embodiment, handle 17 is connected to the link 15 by a pivot connection 21, which is limited in the clockwise direction of movement by the engagement of a pin 22 on the forming member engaging an edge surface 23 of the link. However, handle 17 and forming member 13 connected thereto may be swung in a counterclockwise direction from the position shown in full lines in Fig. 2 to permit facilitated insertion of the tube T into the bending groove 12 to extend perpendicularly tangentially to the bending groove at a bend-start point 24 thereof.As shown in Fig. 2, the mandrel may be provided with a scale 25 having a zero indicator 26 at the bend-start point 24 and other angular indications spaced correspondingly therefrom.

Handle 18, as seen in Fig. 1, includes a connecting portion 27 connected to the mandrel by means of an integral unitary extension 28 of the mandrel defining a mounting means. As further shown in Fig. 1, the handle includes a first portion 29 extending angularly from connecting portion 27, and a second angularly extending portion 30 extending from the distal end 31 of the handle portion 18 angularly back toward the bending plane 19.

In the illustrated embodiment, handle portion 30 defines a gripping portion 32 which extends to at least adjacent bending plane 19 so that the two gripping portions 20 and 32 are effectively located in a common plane of the bending operation so as to effectively avoid force couples tending to twist the tool during the manual bending operation.

Further, as seen in Fig. 4, the provision of the angularly extending portions 18 and 30 with the portion of maximum spacing 31 located generally in alignment with gripping portion 20 of handle 1 7 permits the gripping portion to cross over handle 18 in making large bends such as bends beyond the 90 position shown in Fig. 5.

As will be obvious to those skilled in the art, the location of the gripping portions 20 and 32 may be more or less radially related to the bend axis 14 and relative to the bending plane 19, as desired. Further, the amount of offset of handle 18 may be suitably selected to provide desired clearance of the user's hand on gripping portion 20 relative to handle 18 in the crossover position.

In the illustrated embodiment, handle 1 7 extends substantially rectilinearly, it being obvious to those skilled in the art that other suitable configurations may be utilized for handle 17 as desired. Similarly, the handle portions 29 and 30 of handle 18 extend substantially rectilinearly in the illustrated embodiment, it being obvious to those skilled in the art that the handle 18 may comprise an arcuate arrangement if so desired.

The invention further comprehends improved means for holding tube T against longitudinal displacement during the tube bending operation effected by the manipulation of handles 17 and 18, as discussed above. As best seen in Fig. 5, mandrel 11 defines an integral extension 33 which further defines an integral extension 34 of the bending groove 12 of the mandrel. As seen in Fig.

5, bending groove extension 34 extends from the bend-start point 24 rectilinearly to adjacent the holding means 16 and, thus, defines means for receiving the rectilinear tube T to be bent and holding the tube in position for coaction with the holding means 16. While the groove extension extends rectilinearly, the depth thereof may decrease outwardly toward holding means 16, as illustrated in Fig. 5 by the dotted line illustration of the top 35 of the edges of the groove defined by the mandrel extension portion 33.

In the illustrated embodiment, the tube holding means 16 effectively defines a clamp for clamping the tube T to the mandrel extension 33 in the groove portion 34. More specifically, as seen in Fig. 6, holding means 16 is defined by a hook 36 having a connect ing portion 37 pivotally mounted to mandrel 11 by a pivot pin 38. A spring washer 39 may be provided for providing frictional retention of the hook against free swinging on the pivot pin.

As seen in Fig. 6, hook 36 defines a clamping, pressure-applying surface 40 which is disposed to engage the tube T when disposed in the bending groove extension 34. As seen in Fig. 6, clamping surface 40 extends at an angle so as to define a wedge surface progressively clamping the tube T with increased force as a result of counterclockwise swinging of the hook 36, as seen in Fig. 6.

Surface 40 may include an arcuate end portion 41 limiting the pivotal movement of the hook relative to the tube.

As further seen in Fig. 6, the forming member 13 includes a forming roller 42 which cooperates with a second roller 43, as shown in Fig. 5, in effecting the desired bending of the tube T as the forming member 12 is swung around the mandrel as between the full line position of Fig. 2 and the dotted line 90 position therein. Thus, the clamping action of the hook urging the hook forcibly into clamped seated engagement in the bending groove extension 34 effectively locks the tube T against longitudinal displacement as the forming member 1 3 is moved thereabout.

Referring to Fig. 5, the space 44 outwardly of the hook at the end of groove extension 34 is open so as to accommodate previously bent portions of the tube, such as bent portion 55, thereby permitting formation of multiple bends in the tube T with improved facility.

Thus, the invention comprehends the provision of clamping means for holding the tube to be bent. The provision of a wedging surface on the hook permits the hook to urge the tube forcibly against a support defined by the extension of the mandrel from the bend-start point to provide improved facilitated installation and securing of the tube against longitudinal movement in the bending tool. In one aspect, the tube holding means comprises fixed means carried by the mandrel for supporting the tube and movable means carried by the mandrel for clamping the tube against the support means.

As indicated briefly above, the invention further comprehends the provision of means for providing facilitated mounting of the tube bending tool to a clamping device, such as a vise V, as shown in Fig. 6, when desired.

More specifically, the mounting extension 28 of the mandrel defines a distal block portion 45 which is adapted to be clamped between the jaws 46 and 47 of the vise, as illustrated in Fig. 7. As shown in Fig. 4, the mounting portion 28 includes a handle mounting portion 48 defining a socket 49 for receiving the connecting portion 27 of handle 18. A suitable set screw 50 may be provided in a suitable threaded bore 51 in the mounting portion 28 for releasably locking the handle portion 27 in the socket. Thus, handle 18 may be readily removed from the bending tool when it is desired to mount the bending tool in the vise V, as illustrated in Fig. 6 and 7.

The mounting block portion 45 is free of recesses and openings so as to provide a strong, effectively unconstrictible portion of the mandrel supporting means accommodating the substantial forces which may be generated by the clamping of the vise jaws 46 and 47 thereagainst.

As further illustrated in Figs. 6 and 7, the mounting portion 28 may define a pair of shoulders 52 effectively indicating the disposition of the second portion for facilitated installation of the mounting portion 28 in the vise, as illustrated in Fig. 7. By limiting the insertion of the mounting portion to the mounting block portion 45 thereof, distortion of the handle mounting portion 48, including the socket 49 and bore 51, is effectively precluded, thereby providing improved long troublefree life of the tube bending tool.

Thus, the invention comprehends the provision of a vise mounting portion integral with the mandrel. The arrangement of the vise mounting portion permits forming the bends of the clamping side of the tool, thereby eliminating interference with the handle 18, which, as discussed above, may be removed if desired where the tool is installed in a vise, as shown in Figs. 6 and 7.

In the illustrated embodiment, as shown in Fig. 5, the mounting portion 28 is unitarily and integrally joined to mandrel 11 by a connecting portion 53 which defines a recess 54 in which the connecting portion 37 of the hook is received. As shown in Fig. 6, clockwise swinging of the hook is limited by the engagement of the hook 36 with portion 53.

In use, the operator installs the tube T in the tube bender, as illustrated in Fig. 2, with the tube extending tangentially to the bending groove 12 at the bend-start point 24. The hook 36 is swung into engagement with the tube to clamp the tube against extension portion 33 to lock the tube against longitudinal movement during the bending operation.

During the installation of the tube, handle 17 is swung in a counterclockwise direction from the position of Fig. 2 to space the forming means 13 from the mandrel, permitting facilitated installation of the tube T. The handle 17 is then swung in a clockwise direction to the full line position of Fig. 2. Suitable manipulation of handles 17 and 18 is then effected to move the forming means 13 circumferentially about the mandrel to effect a bending of the tube into the groove 12 to the desired angular extent.

Illustratively, as shown in broken lines in Fig. 2, the forming member may be swung approximately 90 degrees from the full line position thereof to effect a 90 bend in the tube T.

If it is desired to provide a bend of greater extent, such as a 1 80' bend, continued clockwise movement of handle 17 may be effected to cause a crossover between gripping portions 20 and 32 permitted by the substantial clearance of handle portion 31 from gripping portion 20. As further indicated above, the disposition of the gripping portions 20 and 32 substantially at the bending plane 19 eliminates the formation of force couples during the bending operation, providing further facilitated bending of the tube.

The use of the extended tube support groove 34 further assures accurate alignment of the axis of the tube with said bending groove plane 19 at all times.

In the exemplary embodiment of the invention as further disclosed in Figs. 8-10 of the drawing, the manually operable tube bender generally designated 110 is shown to include a mandrel 111 defining an annular peripheral bending groove 112. The tube to be bent T is bent into the forming groove by a forming member 113 which is swung about a bending axis 1 14 of the groove 1 12 by its connection to the mandrel through a link 115. The tube to be bent is held against longitudinal movement during the bending operation by a novel holding means generally designated 11 6.

Movement of the forming member 11 3 about axis 114 is effected by suitable manipulation of a pair of handles 11 7 and 11 8 connected respectively to the forming member 113 and mandrel 111.

In the illustrated embodiment, handle 117 is connected to the link 115 by a pivot connection 119, which is limited in the clockwise direction of movement by the engagement of a pin 120 on the forming member engaging an edge surface of the link.

However, handle 117 and forming member 113 connected thereto may be swung in a counterclockwise direction from the position shown in full lines in Fig. 8 to permit facilitated insertion of the tube T into the bending groove 112 to extend perpendicularly tangentially to the bending groove at a bend-start point 122 thereof. As shown in Fig. 8, the mandrel may be provided with a scale 123 having a zero indicator 124 at the bend-start point 122 and other angular indications spaced correspondingly therefrom.

As indicated above, the invention comprehends improved means for holding tube T against longitudinal displacement during the tube bending operation effected by the manipulation of handles 117 and 118, as discussed above. As best seen in Fig. 8, mandrel 111 defines an integral extension 125 which further defines an integral extension 126 of the bending groove 112 of the mandrel. As seen in Fig. 8, bending groove extension 126 extends from the bend-start point 122 rectilinearly to adjacent the holding means 116 and, thus, defines means for receiving the rectilinear tube T to be bent and holding the tube in position for coaction with the holding means 116.While the groove extension extends rectilinearly, the depth thereof may decrease outwardly toward holding means 1 16, as illustrated in Fig. 8 by the illustration of the top edge 127 of the groove defined by the mandrel extension portion 133.

In the embodiment of Figs. 8-10, the tube holding means 116 effectively defines a clamp for clamping the tube T to the mandrel extension 126 in the groove portion 126.

More specifically, as seen in Fig. 9, holding means 11 6 is defined by a hook 128 having a connecting portion 129 pivotally mounted to mandrel 111 by a pivot pin means 130. A spring washer 131 may be provided for providing frictional retention of the hook against free swinging on the pivot pin.

More specifically, as illustrated in Figs. 8 and 9, pivot pin means 130 is defined by a pin member 132 having a hook mounting portion 133 disposed between a pair of opposite coaxial end portions 134 and 135. Hook mounting portion 133 comprises a cylindrical portion having its axis spaced from the axis of the coaxially disposed end portions 134 and 135 whereby the pin member 132 defines an eccentric pin.

As shown in Fig. 8, pin ends 134 and 135 are rotatably received respectively in cylindrical openings 136 and 137 in the mandrel 111 on opposite sides of a recess 138 to which the distal end 139 of the hook connecting portion 129 is swingably received.

The outer end of pin portion 134 is provided with a transverse slot 140 for cooperating with a tool, such as a screwdriver, in effective rotative adjustment of the pin member about the longitudinal axis of portions 134 and 135 so as to swing hook mounting portion 133 in an arc thereabout. Resultingly, the pivotal mounting of hook 128 is adjusted transversely to the tube T so as to provide desired clamping force of the hook tube engaging portion 141 when the hook is swung into engagement with the tube.

More specifically, the pivot means 130 provides for adjustment of the hook in a direction generally parallel to a radius 142 from mandrel axis 114 through the bend-start point 122.

The invention further comprehends the provision of locking means generally designated 143 for locking the pivot pin 130 in the adjusted position. As shown, the locking means may include a set screw 144 threaded through a threaded opening 145 in the mandrel to communicate with opening 136, permitting the set screw to lock the pin portion 134 in the adjusted disposition.

As shown in Fig. 10, the hook tube engaging portion 146 illustrated therein may in dude an arcuate tube engaging surface 147 defining a wedging surface for wedging the tube T against the mandrel extension 125 in groove extension 126 thereof.

Thus, the invention comprehends the provision of improved adjustable clamping means for holding the tube to be bent. The provision of a wedging surface on the hook further permits the hook to urge the tube forcibly against a support defined by the extension of the mandrel from the bend-start point to provide improved facilitated installation and securing of the tube against longitudinal movement in the bending tool.

Thus, the clamping force exerted on the tube T may be selectively varied by the user of the tool to provide accurately preselected clamping pressure on the tubing so as to permit the tool to be used with tubing having different wall thicknesses and strength without deformation of the tube, while yet providing positive retention of the tube against displacement during the tube bending operation. Further, the improved tool holding means permits the tube to be positioned in any desired position about its longitudinal axis and maintains the held tube accurately relative to the plane of the bending groove of the mandrel and against longitudinal and rotational movement about its longitudinal axis at all times during the bending position.

Still further, the improved adjustable tube holding means permits the tube holding means to be readjusted upon wear of the tool components so as to maintain the clamping pressure at the desired values notwithstanding such wear.

In the illustrated embodiment, the hook adjusting means comprises an eccentric pin.

As will be obvious to those skilled in the art, such camming adjustment may be effected by other suitable structures and it is intended that the illustrated eccentric pin hook means is exemplary only of the broad concept of means for adjusting the disposition of the hook pivot axis, as desired.

The provision of the locking means 143 assures the maintenance of the pivot axis of the hook in the adjusted disposition for repeatable bending of a plurality of tubes with the preselected clamping force and disposition of the hook tube engaging means.

In use, the operator installs the tube T in the tube bender, as illustrated in Fig. 8, with the tube extending tangentially to the bending groove 112 at the bend-start point 122. The hook 128 is swung into engagement with the tube to clamp the tube against mandrel extension portion 125 to lock the tube against longitudinal movement during the bending operation.

As discussed above, the disposition of the pivot axis of hook 128 is caused to be accurately the desired disposition by suitable adjustment of the pivot pin 30 to provide suitably correspondingly adjusted clamping force to the tube to be bent.

During the installation of the tube, handle 117 is swung in a counterclockwise direction from the position of Fig. 8 to space the forming means 113 from the mandrel, permitting facilitated installation of the tube T. The handle 117 is then swung in a clockwise direction to the full line position of Fig. 8.

Suitable manipulation of handles 117 and 118 is then effected to move the forming means 113 circumferentially about the mandrel to effect a bending of the tube into the groove 12 to the desired angular extent, the improved tube holding means 16 positively assuring that the tube will be held against longitudinal and rotational displacement during the bending operation.

In the further exemplary embodiment of the invention as disclosed in Fig. 11 of the drawing, a manually operable tube bender generally designated 210 is shown to include a form wheel 211 defining an annular peripheral bending groove 212. A tube to be bent T is bent into the forming groove by a forming member 213. The forming member is swung about a bending axis 214 of the groove 212 by means of a swing link 215 having one end pivotally connected to the forming member by a pivot 216 and the opposite end connected to the forming member 213 by a pivot connection 217.

Tube T is held against longitudinal displacement during the bending operation by a hook 218.

Movement of the forming member 213 relative to form wheel 211 is effected by manipulation of a handle 220 connected to the form wheel 211. As shown in Fig. 11, when handle 219 is swung to bring the forming member 213 to a bend-start position, link 215 is positioned by its engagement with a suitable stop shoulder element provided on the rear face 222 of the form wheel 211. As further illustrated in Fig. 11, forming member 213 may be provided with an indicium 223 juxtaposed to a scale 224 carried by the form wheel 211 for indicating the disposition of forming member 213 in the bend-start position illustrated in Fig. 11 and for indicating the angular extent of the bend formed in the tube.

As indicated briefly above, a problem arises in such swingable forming member tube benders in that, as a result of wear of the components of the tube bender, a loose fit may result between the forming member and the tube held in the bending groove. It is necessary to have proper force transfer engagement of the forming member with the tube in order to prevent undistorted bends and to meet standards of ovality of the bent tube such as required by the Nuclear Code, etc. One solution to this problem employed in heavy duty bench-type tube benders is to provide a screwed clamping arrangement which forces a contoured follower shoe against the tubing prior to the bending. The contoured shoe is a separate loose piece which is placed in position and requires that the clamping adjustment must be made and released each time a bend is made with the tool.High frictional forces are generated as a result of the requirement of high clamping force. In such structure, the follow bar is a loose member which is free to move longitudinally of the tube bend so that the tube will remain undamaged. The necessary high forces would require, in a manually operable tube bender, extremely long operating handles to provide the necessary moment arms.

The present invention eliminates the need for such adjustable contoured shoe structures by providing means for adjusting the position of the forming member 213 toward and from the peripheral edge 225 of the form wheel 211 so as to cause the forming member to have desired accurate force transfer engagement with the tube T. In the illustrated embodiment, the adjustment of the forming member is effected by the provision of an adjustable pivot 217 defined by a pivot pin having a first mounting portion 226 pivotally mounted in a bore 227 of the forming member body 228, as illustrated in Fig. 12. A second cylindrical portion 229 of the pivot pin 217 is pivotally received in a bore 230 of link 215. Axis 231 of cylindrical portion 229 is offset from the axis 232 of cylindrical portion 226 and, thus, the pivot pin 217 defines an eccentric pin.As further shown in Fig. 12, one end of the pin is provided with a head 233 adapted to be engaged by a suitable tool, such as a wrench, and the opposite end of the pin is threaded as at 234 for threaded engagement with a suitable nut 235.

Adjustment of the forming member 213 toward and from the form wheel edge 225 is effected by the turning of head 233 so as to displace axis 232 of cylindrical portion 226 toward or from the form wheel edge 225 as it swings about the axis 231 of cylindrical portion 229. During such adjustment, nut 235 may be loosened on threaded end 234 and upon completion of the adjustment, the retightening of the nut 235 secures the pivot means in the adjusted disposition.

As will be obvious to those skilled in the art, the eccentric adjusting means is exemplary, the invention comprehending that any suitable means for adjusting the position of the forming member 213 radially of the bend axis 214 may be utilized within the scope of the invention.

As shown in Fig. 11, the scale 224 may comprise an adjustable scale adjustably mounted to the form wheel 211 by a suitable screw 236 extended through an arcuate slot 237 in the scale 224. Thus, the scale 224 may be adjusted to line up with the indicium 223 identifying the bend-start point in each of the adjusted positions of the forming member.

In the illustrated embodiment, the adjusting means is infinitely adjustable, it being obvious to those skilled in the art that discrete adjusting means are equally comprehended within the broad scope of the invention.

In the illustrated embodiment, the forming member is provided with a pair of rollers 238 and 239 which are rotatably mounted between a pair of side plates 240 and 241 depending in spaced relationship from the forming member body portion 228. Roller 238 is axially aligned with the bend-start indicium 223 and roller 239 is spaced outwardly therefrom so as to engage a portion of the tube T longitudinally outwardly from the portion engaged by roller 238, and, as seen in Fig. 11, at a position spaced radially outwardly of the edge 225 of the form wheel 211.Thus, as handle 219 is swung in a clockwise direction, as seen in Fig. 11, the forming member rollers 238 and 239 cooperate in bending the tube into the form wheel groove 212, with the leading roller 239 firstly deflecting the outwardly extending portion of the tube T toward the form wheel edge 225 and the roller 238 urging the tube firmly into the groove.

As indicated above, the invention further comprehends an improved arrangement of the force transfer surface on the forming member 213 for transferring the bending force from the forming member to the tube T. As best seen in Fig. 14, the forming member defines a concave tube-engaging surface generally designated 242 for engaging the tube and effecting the force transfer thereto. The tubeengaging surface further defines side surface portions 243 and 244 engaging side portions 245 and 246 of the tube outwardly adjacent the form wheel edge 225 and 212 therein.

The concave surface 242 further defines a bight portion 247 between the surface portions 243 and 244 arranged to have clearance with the radially outermost portion 248 of the tube between the side portions 245 and 246.

The invention comprehends that the engagement between the forming member force transfer surface portions 243 and 244 and the tube be over a limited angular extent illustrated in Fig. 14 as angle f. As shown in Fig. 14, the side portions of the tube 245 and 246 engaged by the side surfaces of the forming member are angularly spaced at least approximately 15 degrees from a plane 249 drawn through the cross-sectional center 250 of the tube perpendicular to a radius 251 extending through said tube center 250 from the bend axis 214. The side portions of the tube engaged by the forming member extend outwardly to a position no greater than approximately 45 degrees from plane 249 and, thus, the angle f extends approximately 30 degrees in the illustrated embodiment.

As illustrated in Fig. 14, the side surfaces 243 and 244 of the forming member may be rectilinear in transverse cross section so as to have effectively minimum surface contact with the engaged surfaces of the tube 245 and 246. Alternatively, however, the surfaces of the forming member may be rounded, such as surfaces 252 and 253 of the forming member 254 illustrated in Fig. 15. Thus, in the embodiment of Fig. 14, the bight portion 247 is substantially trapezoidal in transverse cross section, whereas the bight portion 255 of the forming member 254 is rounded, such as in an arch configuration, in transverse section, as illustrated in Fig. 15.The specific configuration of the bight portion of the concave surface does not appear to be critical in the invention as long as clearance is provided relative to the outermost portion 248 of the tube to be bent with the force transfer engagement of the forming member side surface portions being with portions of the tube outwardly of the form wheel groove of limited angular extent.

As a result of the force transfer from the novel arrangement of force transfer surface portions of the forming member hereof, the tube bending forces are applied at a region of the tube where a relatively thick wall is maintained as compared to the stretched outermost portion 248 thereof.

No direct flattening force is applied to the outermost portion 248 of the tube, and the bending forces transmitted from the bending surfaces 243, 244, 252 and 253 define transversely inwardly directed components resisting lateral spreading of the tube, thereby further effectively minimizing flattening or increased ovality of the tube as a result of the bending operation.

The invention comprehends that at least the roller disposed adjacent the bend-start position, such as roller 238 in the embodiment of Fig. 11, be provided with the improved concave force transfer configuration discussed above. The outboard roller, such as roller 239 in. the embodiment of Fig. 11, may utilize the novel surface configuration, although it has been found that satisfactory bending of the tube may be effected with the outboard roller utilizing a conventional tube-engaging surface configuration. As will be obvious to those skilled in the art, where the forming member comprises a shoe wherein the force transfer surface is defined by a longitudinal groove in the shoe, the entire groove transverse cross section may utilize the above discussed improved force transfer configuration. It is preferred that at least the portion of the groove adjacent the bend-start point have such configuration.

As indicated above, the adjustability of the forming member toward and from the bending groove permitted by the adjustable mounting means cooperates with the improved force transfer surface configuration in providing an improved tube end with minimum stress and ovality. Thus, the tube bender structure 210 provides improved means for complying with the relatively strict nuclear power plant requirements for bent tubes, as set out in Section III of the ASME Code, while yet the tube bender structure is extremely simple and economical of construction.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

Claims

1. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis to define a bending plane, a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, and means for holding the tube against longitudinal displacement in said bending groove during a tube bending operation, the improvement comprising: a first handle connected to the forming member and having a distal end defining a first gripping portion at said bending plane; and a second handle having a connecting portion connected to the mandrel and extending therefrom away from the bending plane and defining a second gripping portion connected to the distal end of the connecting portion and extending therefrom toward the bending plane, said second gripping portion being disposed at a distance from said bending axis a distance greater than the spacing of said first gripping portion therefrom, whereby said first gripping portion may be swung about said bending axis to adjacent said second gripping portion free of interference between the user's hands on said gripping portions.

2. The manually operable tube bender of Claim 1 wherein said second handle connecting portion extends substantially rectilinearly angularly away from said bending plane and said second handle gripping portion extends substantially rectilinearly angularly toward said bending plane, said distal end of said second handle connecting portion being spaced from said bending axis a distance substantially equal to the spacing of said first gripping portion therefrom to provide therebetween effectively maximum clearance between said handles.

3. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis to define a bending plane, a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, and means for holding the tube against longitudi nal displacement in said bending groove during a tube bending operation with the tube extending rectilinearly perpendicularly to a radius from the bending axis at a bend-start point of the bending groove, the improvement comprising means defining a rectilinear groove extending away from said bending groove at said bend-start point to adjacent said means for holding the tube for receiving a portion of the tube to be bent, said means for holding the tube comprising means for clamping said tube portion to said groove defining means.

4. The manually operable tube bender of Claim 3 wherein the depth of the rectilinear groove decreases away from said bend-start point.

5. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis to define a bending plane, and a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, improved means for holding the tube against longitudinal displacement in said bending groove during a tube bending operation with the tube extending rectilinearly perpendicularly to a radius from the bending axis at a bend-start point of the bending groove, comprising clamp means adjacent said bend-start point for releasably clamping the rectilinearly extending tube to the mandrel.

6. The manually operable tube bender of Claim 5 wherein said clamp means comprises a hook swingably connected to the mandrel and defining a pressure-applying wedge surface engaging the tube portion extending rectilinearly from the bend-start point, said wedge surface being arranged to provide increasingly greater clamping force against said tube as an incident of swinging of the hook and an arcuate stop surface for abutment with the tube for limiting the swinging of the hook to a maximum pressure-applying position.

7. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis to define a bending plane, a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, and means for holding the tube against longitudinal displacement in said bending groove during a tube bending operation, the improvement comprising: a first handle connected to the forming member; a second handle; and mounting means extending from said mandrel and defining first and second mounting portions, said first mounting portion being arranged to have said second handle connected thereto for use in effecting a tube bending operation as an incident of manipulation of the two handles, and said second mounting portion being arranged to be mounted in a vise for use in effecting tube bending operations as an incident of movement of said first handle while the mandrel is fixedly held by the vise.

8. The manually operable tube bender of Claim 7 wherein said first handle has a distal end defining a first gripping portion at said bending plane, and said second handle has a connecting portion connected to said first mounting portion and extending therefrom away from the bending plane and defining a second gripping portion connected to the distal end of the connecting portion and extending therefrom toward the bending plane, said second gripping portions being disposed at a distance from said bending axis a distance greater than the spacing of said first gripping portion therefrom, whereby said first gripping portion may be swung about said bending axis to adjacent said second gripping portion free of interference between the user's hands on said gripping portions.

9. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis, and a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, improved means for holding the tube against longitudinal and rotational displacement in said bending groove during a tube bending operation, said tube holding means comprising: means for supporting a portion of the tube in a clamping space adjacent the mandrel; a clamp member; means for mounting the clamp member for movement into and from engagement with a tube supported by said supporting means in said clamping space to clamp the tube to the supporting means; and means for selectively adjusting the disposition of the mounting means for providing a desired clamping force applied by said clamp member to the tube.

10. The manually operable tube bender of Claim 9 wherein said means for mounting the clamp member comprises means for swingably mounting the clamp member to the mandrel.

11. The manually operable tube bender of Claim 9 wherein said means for selectively adjusting the disposition of the mounting means comprises means for moving the clamping member toward and from said clamping space and means for locking the means for moving the clamping member in adjusted disposition.

12. In a manually operable tube bender having a mandrel defining a tube-receiving bending groove extending arcuately about a bend axis, and a forming member mounted to said mandrel to swing about said bend axis for urging a tube to be bent into said bending groove, improved means for holding the tube against longitudinal and rotational displacement during a tube bending operation, said tube holding means comprising: means for supporting a portion of the tube in a clamping space adjacent the mandrel; a clamp member; pivot means for mounting the clamp member for swinging movement into and from engagement with a tube supported by said supporting means in said clamping space to clamp the tube to the supporting means; and means for selectively transaxially adjusting the disposition of said pivot means for correspondingly adjusting the clamp member toward and from the clamping space.

13. The manually operable tube bender of Claim 12 wherein said means for adjusting the pivot means comprises rotatively adjustable means.

14. The manually operable tube bender of Claim 12 wherein said means for adjusting the pivot means comprises rotatively adjustable means, said tube bender further including friction means for retarding free swinging movement of the clamp member acting between said clamp member and said mandrel coaxially of one of said eccentric means and said pivot pin.

15. In a tube bender having a form wheel defining a tube-receiving bending groove extending arcuately about a bend axis, and means for holding the tube to be bent against longitudinal movement in the bending groove during a tube bending operation, the improvement comprising: a forming member defining a concave tubeengaging surface; and adjustable mounting means for mounting the forming member to the form wheel to swing about said bend axis outwardly adjacent said bending groove at any one of a plurality of different distances radially from said bending axis to have desired bending force transfer engagement with the tube to be bent outwardly of the bending groove.

1 6. The tube bender of Claim 15 wherein said adjustable mounting means includes a swing member pivotally mounted to the form wheel, means for adjustably mounting the forming member to the swing member, and shoulder means on said form wheel for positioning the swing member in a preselected bend-start position for permitting adjustment of the radial positioning of the forming member with the forming member disposed in the bend-start position thereof.

17. The tube bender of Claim 15 wherein said form wheel is provided with an angle scale adjustably mounted thereto.

18. In a tube bender having a form wheel defining a tube-receiving bending groove extending arcuately about a bend axis, means for holding the tube to be bent against longitudinal movement in the bending groove during a tube bending operation, a forming member, and mounting means for mounting the forming member to the form wheel to swing about said bend axis outwardly adjacent said bending groove to have bending force transfer with the tube to be bent outwardly of the bending groove, the improvement comprising the provision on said forming member of a concave tube-engaging surface for engaging the tube in effecting the force transfer thereto, said tube-engaging surface defining side surface portions engaging side portions of the tube outwardly adjacent the form wheel groove and a bight portion arranged to have clearance with the radially outermost portion of the tube between said side portions of the tube.

1 9. The tube bender construction of Claim 18 wherein said side portions of the tube are angularly spaced at least approximately 15 from a plane through the cross-sectional center of the tube perpendicular to a radius through said center from said bend axis and extend outwardly to a position no greater than approximately 45 to said plane.

20. In a tube bender having a form wheel defining a tube-receiving bending groove extending arcuately about a bend axis, and means for holding the tube to be bent against longitudinal movement in the bending groove during a tube bending operation, the improvement comprising: a forming member defining a concave tubeengaging surface; and adjustable mounting means for mounting the forming member to the form wheel to swing about said bend axis outwardly adjacent said bending groove at any one of a plurality of different distances radially from said bending axis to have desired bending force transfer engagement with the tube to be bent outwardly of the bending groove, said concave tube-engaging surface of the forming member defining side surface portions engaging side portions of the tube outwardly adjacent the form wheel groove and a bight portion arranged to have clearance with the radially outermost portion of the tube between said side portions of the tube.

21. The tube bender of Claim 20 wherein said adjustable mounting means are adjusted to cause said side surface portions of the forming member tube-engaging surface to engage said side portions of the tube in the range of at least approximately 15 and no greater than approximately 45 from a plane through the cross-sectional center of the tube perpendicular to a radius through said center from said bend axis.

22. A tube bender substantially as hereinbefore described with reference to the accompanying drawings.