US3789640A

US3789640A - Hand held tube bender

Info

Publication number: US3789640A
Application number: US00278077A
Authority: US
Inventors: H Frank
Original assignee: Emerson Electric Co
Current assignee: Emerson Electric Co
Priority date: 1972-08-04
Filing date: 1972-08-04
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05

Abstract

A tube bender is shown which has a handle on which is rotatably mounted a bending mandrel with a tube engaging hook swivably carried by the mandrel and with the mounting for the hook being a crank or eccentric so that when the mounting is rotated the hook is moved toward or away from the groove of the mandrel. The hook is also offset so that it may engage a tube close to the start of the bend point on the mandrel. The mandrel is rotatable on the handle and held in different positions thereon by a detent means. The bending shoe is on the end of a second handle and is pivotably connected to a link plate which is rotatably journalled on an annular bearing surface on the mandrel between the mandrel and the first handle.

Description

llnited States Patent [1 1 Frank 111 Magma Feb. 5, 1974 HAND HELD TUBE BENDER [75] Inventor: Heinrich l-I. Frank, Amherst, Ohio [73] Assignee: Emerson Electric Co., St. Louis, Mo.

[22] Filed: Aug. 4, 1972 [21] Appl. No.1 278,077

[52] U.S. Cl.....'. 72/36, 72/388 Primary Examiner-Charles W. Lanham Assistant Examiner-Robert M. Rogers Attorney, Agent, or Firm.l. Darrell Douglass [5 7] ABSTRACT shown which has a handle on which is rotatably mounted a bending mandrel with a tube engaging hook swivably carried by the mandrel and with the mounting for the hook being a crank or eccentric so that when the mounting is rotated the hook is moved toward or away from the groove of the mandrel. The hook is also offset so that it may engage a tube close to the start of the bend point on the mandrel. The mandrel is rotatable on the handle and held in different positions thereon by a detent means. The bending shoe is on the end of a second handle and is pivotably connected to a link plate which is rotatably joumalled on an annular bearing surface on the mandrel between the mandrel and the first handle.

18 Claims, W

HAND HELD TUBE BENDER BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to hand held tubing or rod benders for enabling bends to be made in tubes or rods encompassing many degrees of bends mostly from to 180 useful in the plumbing and refrigeration industry or in any place where a tubing system is being constructed to carry a liquid or a gas.

2. Description of the Prior Art The prior art is best exemplified in US. Pat. No. 3,194,038 and, as can be seen, usuallycomp rised a handle, to be gripped by one hand and carrying on the end a generally circular mandrel having a groove in its periphery for receiving a tube to bebent. A bending shoe is carried on the end of a second handle and attached to the mandrel by a link pivoted at one end on the axis of the mandrel and the other end to the bending shoe and its handle. A tube is placed in the groove of the mandrel with one end extending alongside the handle and the part to be bent extending in the groove tangent to the bottom of the groove. A holding hook pivoted at its base on the mandrel is swung over and holds the end of the tube that extends alongside the mandrel. The handle with the bending shoe is then swung around so that the shoe engages the tube at the place where the bend is to be started. The handle with the shoe is then rotated around the mandrel to bend the tube into the groove in the mandrel, the bend taking the curvature of the groove in the mandrel. Usually bends from 0 to 180 may be made. In many benders such as that of US. Pat. No. 3,194,038 when a 180 bend is made, the handles must be extended at the start of the bend so that they are 180 apart as shown in FIG. 8 of that patent. This puts the operator at a disadvantage since it is extremely difficult, especially with hard tubing, to start a bend with the handles fullye xtended.

Another disadvantage of the prior art resided in the fact many of these devices, particularly in the type of bender the subject of this application, the tube was held by a hook which obviously had to be engaged with tube after the tube was in place, and therefor had tangential engagement with the tube. With this type of engagement there was a tendency to flatten or dent the tube at the point of ergagement.

In addition, the tube engaging hook was so disposed that it was outward of the place where the bend was started (zero point) and therefor the bend could not be started close to the end, with the result that frequently it was necessary to cut off the stub, where a joint was to be made close to the bend, which was time consuming and wasteful of material. As can be seen from US. Pat. No. 3,194,038 the mandrel, about which the bend is made, is usually provided with a flat portion removed along a chord into which the fixed handle is secured, and the hook is swivably mounted on the handle. In addition, it is frequently desirable to make a bend in a tube, which has a coupling on the end with the bend close to the coupling. With the prior device the placement of the hook was so far outward, and the coupling had to be outwardly of the hook, that a bend could notbe made close to the coupling.

SUMMARY OF THE INVENTION able the desired degree of adjustment.

This is accomplished by mounting the hook on a r0 tatable eccentric pivot so that the hook with its seat, which matches the periphery of the tube, may be swung over the tube and then rotated to bring the hook seat into engagement with the tube surface.

In addition, the hook is so shaped that its seat engages with the tube at a place close to the start of the bend.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. I, is an elevational view of the invention taken from one side and with the handle broken away to forshorten the view;

FIG. 2, is a view from the end of FIG. 1;

FIG. 3, is a section taken on the line 3 3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The bender includes a base handle 10 which can be a stamping formed to provide a straight narrow hand grip part 10a of generally C shaped cross section and .then curves 10b toward and ends in a generally circular end mandrel support portion 10c. The end part 10c has a flat support surface 10d and has a central pivot aperture We and in spaced concentric relation a series of detent apertures 10f each equally spaced from the pivot aperture and 45 apart.

A bending mandrel 20 is pivotally secured to the mandrel support and includes circular a base 20a having a central stub shaft to provide a pivot 20b disposed in the aperture 10e of the handle base and having a stem 20c which extends through a washer 22 and may be headed over at 20d. The length of the pivot part 20b is such that when the stem 20c is headed over the base 20a is disposed close to the base 10d but is free to revolve thereon. The mandrel is bored at 20f to provide a blind opening for the reception of an enlarged skirt 24 of a hollow detent plunger. The plunger has a head 24a of reduced size for engagement in any one of the detent apertures 10f in the base. A spring 26 disposed in the plunger engages with the bottom of the bore and the inner end of the hollow plunger to hold it pressed toward the base 100. Thus the head of the detent plunger, which is chamfered, may be pressed inward to free it from locking engagement with any of the apertures and the mandrel rotated to any of the positions 45 apart.

Although five apertures 10f have been shown, it is apparent that more or less holes could be provided and allow themandrel to be rotated in 45 increments to any position relative to the base handle. In practice it has been found that four such apertures will usually en- The base a of the mandrel is surmounted by an enlarged body 20g of generally circular form except at the place 2011 where a portion is removed along a chord to provide a seat where a tube holding hook is attached, later described in detail. The periphery of the body 203 is formed with a tube receiving groove 20j of generally semi-circular cross-section although it preferably has a I80 bottom portion merging with straight sidewalls which assist in preventing flattening of a tube during a bending operation as is well known in the art. The groove intersects the place where the material is removed at the chord 20h.

The tube holding hook, as can best be seen from FIGS. 1 and 2, which shows it in tube engaging position, comprises an apertured base 30 extending outwardly of the face of the mandrel and then bends at a right angle at 30a to provide a portion 30b which again bends downward to extend over the face of the mandrel and then a bend 30c to provide a part 30d which extends over and opposite the periphery of the mandrel and terminates in a hook 30e which is opposite the mandrel groove 20j. Opposite to the mandrel groove, the hook is formed with a semi-circular tube engaging surface 30f. It will thus be seen that the hook is C shape in profile when viewed from the end, FIG. 2, and Z shape in profile when viewed from the side, FIG. I.

The hook is held on the seat 2012 of the mandrel by an adjustable pivot member which includes a cylindrical body 40 disposed in a blind bore 20k that extends into the mandrel from the seat 20h on a diameter of the mandrel. On its outer end the body is provided with an eccentrically disposed circular portion 40a of reduced diameter which extends through the apertured base 30 of the tube holding hook and terminates in a knurled knob 40b pressed onto the end of the eccentric part 40a thusly holding the hook against the seat and on the adjusting member. The end portion of the adjusting member, within the bore, is of reduced diameter at 40c providing perpendicular side walls flanking the part of reduced diameter. The center of the mandrel is drilled at 20m to provide a blind hole at the bottom of which is disposed a spring pressed plunger 42, which is a hollow body with a spring 44 having one end disposed in the body and engaging the other end of the bore to urge the plunger against the reduced part 40c of the adjusting member. The part 400 is formed with a pair of diametrically opposed flats 40d which provide seats for the plunger 42 thus enabling the pivot member to be held in any one of two adjusted positions 180 apart. The plunger indexes the position of the pin 40 and also retains the pin in position. A hole 40f through the flats 40d allows a tool to be inserted to depress the plunger should removal be desired. As can best be seen from FIG. 1, the adjustable member is shown in a position where the hook 30e is closest to the groove in the mandrel and it may be rotated 180 from the position shown to cause the hook to move outwardly of the mandrel.

tends outwardly beyond the periphery of the mandrel as best shown in FIG. 1. At the outer end of the link the bending shoe 50 is securely connected to the link by a headed pin 54. A roll pin 56 set into the link, is disposed in the path of rotation of the shoe 50 and its handle and is engaged by the shoe when the handle is rotated clockwise to cause the shoe and link to attain a fixed position relative to each other during a bending operation. The shoe has a bending groove 50c extending longitudinally on its face opposite to the groove 20j in the mandrel.

In operation the mandrel is first set to the desired position for the degrees of bend to be made. The position of the parts as shown in FIG. 1 is not necessarily the position that would be taken at the start of a normal bending operation since the parts are shown in position for better illustration of the components. However it could be used, but would require moving the shoe handle across the mandrel handle if there was an aperture 10f to receive the mandrel detent 24 in the position shown. Therefor it will be assumed that there is a first detent receiving apertures 10f and that the detent 24 will be depressed and the mandrel rotated counter-clockwise to the next detent aperture 10f for a 45 bend.

It will be noted that the free end of the detent 24 is chamfered and therefor it need not be fully depressed but merely depressed far enough for the chamfered edge to engage with the inner face edge of an aperture 10f and movement will cause it to be cammed to the right (FIG. 3) and it will ride on the face 10d of the base while the mandrel is rotated until the detent finally becomes aligned with one of the apertures 10f at which time it will snap into the aperture and provide a fixed alignment of the mandrel with the handle 10.

The mandrel having been moved to the position described, the hook is rotated about its pivot to a position perpendicular to the mandrel. The shoe handle is then swung from the position shown outward and a tube inserted in the mandrel groove. The tube can be laid in the space between the shoe and mandrel with a place or marking on the tube opposite the 0" degree reference point. This can easily be done because the hook and shoe have been moved to positions to allow free access to the groove.

It will be assumed the the knob 40b has bee rotated 180 degrees, from the position shown in FIG. 1, to

cause the hook to be moved outwardly of the mandrel, this being the position it was adjusted to when the last tube that was bent was taken out. The hook can now be swung about its pivot 40b to the position shown in FIG. 1, over the tube that is to be bent. At this time the intermediate part of the hook lies against the face of the mandrel. The knob 40b is then rotated I which draws the hook back toward the mandrel with the seat 30]" of the hook in engagement with the periphery of the tube and holding this tube in the bottom of the mandrel groove. It will be noted that the seat 30f provides as much or more than of contact with the tube as contrasted to the prior art which had tangent contact with the tube. Thus, since there is considerable pressure on the tube at this point during the bending operation, due to the extended area of contact there is less tendency to nick or flatten the tube.

The shoe handle is then rotated clockwise unitl it engages with the projection pin 56. At this time the groove 50c in the shoe engages with the periphery of the tube and presses it into the mandrel groove 20j. The

is. "libs-f shoe handle 50a, which is now 45 removed from the base handle, is moved toward the base handle which causes the shoe to follow the periphery of the mandrel and bend the tube, as it slides along the tube, to the contour of the mandrel groove. The markings on the mandrel and the shoe enable the operator to determine the exact number of degrees of bend that have been made. It is pointed out that the markings illustrated are bends most commonly made and that there could be more markings than shown that would provide a greater variance in the degrees of bend to be made.

It will thus be seen that because of the Z shape of the tube holding hook, the tube is held at a place closer to the point where a bend is started. This enables tubes with a coupling such as C (FIG. l) to be bent close to the coupling and results in less wastage of tube when a bend has to be made close to the end.

It is also apparant that a considerable advantage is realized when bends of greater than 90 are to be made. For instance on 180 or 135 bends, the handles would ordinarly be 180 to 135 apart. With the handles 180 apart, the least pressure can be exerted on the handles to bring them together. Obviously the greatest bending pressure can be realized the closer the handles are together.-Therefor in making a 135 or larger bend, it is expedient to set the tool for 45, make a 45 bend, then release the base handle from the mandrel and move it another 45 and continue the bend. Thus bends up to 180 can be made easily and quickly because of the fact that the rotated position of the mandrel on the base handle can be quickly and easily changed.

As can best be seen from FIG. 3, the base handle is spaced from the shoe handle. This allows the shoe handle to cross over the base handle if desired. For ina 90 bend, bends up to 180 could be made by causing the shoe handle to pass over the base handle.

I claim:

1. A tube bending tool having a first handle, a substantially circular mandrel rotatably secured on the end of the said handle and having a peripherial groove, means cooperating with the handle and mandrel to quickly and adjustably fix the position of the mandrel on the handle, a. tube holding hook arranged to hold a tube opposite the groove in the mandrel, a second handle having a tube bending shoe pivotally connected to the first handle and mandrel, said shoe being having a bending surface movable along the periphery of the mandrel by said handle to bend the tube to the contour of the. groove in the mandrel.

2. A tool as described in claim 1 wherein said mandrel has a portion removed along a chord to provide a seat for said hook and said hook is pivotally secured on the seat.

3. A tool as described in claim 2 wherein a pivot means is provided on said hook seat and said hook is journalled on said pivot means.

4. A tool as described in claim 3 wherein said pivot means comprises a member rotatably journalled in said mandrel and has an eccentric portion of reduced diameter upon which the hook is journalled, extending beyond said hook seat.

5. A tool as described in claim 4 wherein a control knob is provided on the end of said eccentric portion to hold Said hook ersaa ns .st ablsthaair lz ea 6. A tool as described in claim 4 wherein index means is provided in said mandrel for engagement with said pivot means to index the pivot means in at least two po- 'sitions.

7. A tool as described in claim 6 wherein said hook has a portion extending over the face of the mandrel and beyond the edge thereof and a second portion extending opposite to the mandrel groove at the periphery of the mandrel.

'aTA'EBBTaKHsCnBd in clairn 7 wherein the portion of the hook extending opposite the groove in the mandrel is provided with a tube engaging seat having substantially the same curvature as the transverse periphery of a tube to be bent.

y Tmm'fi claim 7 wherein said hook where it extends over the face of the mandrel and beyond the edge thereof, has the part opposite the mandrel groove close to the start of a bend point for a tube.

12. A tool as described in claim 11 wh erein said re duced portion is formed with a pair of flats on opposite sides for engagement by the detent means to index the pivot means at points apart.

' A toarasaa ema'i'aaaawherein said first handle has a circular end portion against which the mandrel is seated and said mandrel is formed with an indented bearing surface adjacent said circular end portion and said pivoted connection for the bending shoe and its handle to the first handle includes a link having a ring portion disposed on said bearing surface between the mandrel and said circular end portion and an outwardly extending portion pivotally connected to said second handle. Y W V v V V 7 14. A tool as described in claim 13 where said link has a projection extending in the path of travel of said pivoted shoe to engage the shoe and hold the shoe and link in predetermined relation to each other during a bending operation.

153E601 as described in claim 14 wherein said projection on the link is a pin set into the link and extending outwardly from the face thereof.

16. A tool as described in claim 1 wherein said first handle diverges from the second handle.

17. A tool as described in claim 1 wherein said first handle has a circular end portion against which the mandrel is seated and said end portion is formed with a series of apertures disposed equi-distant from the axis and said mandrel carries a detent means for selective engagment in any one of the apertures.

18. A tool as described in claim 17 wherein said detent means is a spring pressed means disposed within the mandrel and has a reduced diameter part extended outwardly therefrom for engagment in the apertures.

Claims

1. A tube bending tool having a first handle, a substantially circular mandrel rotatably secured on the end of the said handle and having a peripherial groove, means cooperating with the handle and mandrel to quickly and adjustably fix the position of the mandrel on the handle, a tube holding hook arranged to hold a tube opposite the groove in the mandrel, a second handle having a tube bending shoe pivotally connected to the first handle and mandrel, said shoe being having a bending surface movable along the periphery of the mandrel by said handle to bend the tube to the contour of the groove in the mandrel.

5. A tool as described in claim 4 wherein a control knob is provided on the end of said eccentric portion to hold said hook thereon and enable the pivot means to be turned.

6. A tool as described in claim 4 wherein index means is provided in said mandrel for engagement with said pivot means to index the pivot means in at least two positions.

8. A tool as described in claim 7 wherein the portion of the hook extending opposite the groove in the mandrel is provided with a tube engaging seat having substantially the same curvature as the transverse periphery of a tube to be bent.

9. A tool as described in claim 7 wherein said hook, where it extends over the face of the mandrel and beyond the edge thereof, has the part opposite the mandrel groove close to the start of a bend point for a tube.

10. A tool as described in claim 6 wherein said mandrel is provided with a bore for said pivot means and a second bore for the index means and said pivot means has a pair of flats and a detent means is disposed in the second bore and spring pressed toward the pivot means.

11. A tool as described in claim 10 wherein said pivot means has a portion of reduced diameter and said detent means engages said portion to hold the pivot means in the bore.

12. A tool as described in claim 11 wherein said reduced portion is formed with a pair of flats on opposite sides for engagemenT by the detent means to index the pivot means at points 180* apart.

13. A tool as described in claim 1 wherein said first handle has a circular end portion against which the mandrel is seated and said mandrel is formed with an indented bearing surface adjacent said circular end portion and said pivoted connection for the bending shoe and its handle to the first handle includes a link having a ring portion disposed on said bearing surface between the mandrel and said circular end portion and an outwardly extending portion pivotally connected to said second handle.

14. A tool as described in claim 13 where said link has a projection extending in the path of travel of said pivoted shoe to engage the shoe and hold the shoe and link in predetermined relation to each other during a bending operation.

15. A tool as described in claim 14 wherein said projection on the link is a pin set into the link and extending outwardly from the face thereof.