USRE24449E - Hand-operated - Google Patents

Description

April 1, 1958 H. L. PHILIPPE HAND-OPERATED, PLIER-TYPE TUBE BENDER Original FilPf Deo.- 30, 1955 TT 'd l 20 Z5 `stretching forces produced on UnitedStates Patent Office 24,449 HAND-OPERATED, PL'IER-TYPE TUBE BENDER Howard L. Philippe, Chicago, lll., assignor to The Imperla! Brass Manufacturing Company, a corporation of Illinois Original No. 2,796,785, dated June 25, 1957, Serial No. 556,638, December 30, 1955. Application for reissue September 5, 1957, Serial No. 682,998

5 Claims. (Cl. 81-15) Matter enclosed in heavy brackets appears in the original cation; matter printed in italics indicates the additions made by reissue.

ymandrel for pressing the tube into the mandrel groove.

patent but forms no part of this reissue specifi-v It has been found, however, that the friction between the shoe and the tube during the bending process tends to movethe tube longitudinally through the mandrel groove in the direction of movement of the shoe, with an imperfect bend resulting. To prevent such longitudinal movement, various forms of tube retaining members are used, for example, hooks and clamps which are secured in lxed relationship to the mandrel and arranged to engage the peripheral surface of the tubing adjacent the mandrel. Such members have the serious disadvantage of gouging'the tube surface during use and/or requiring additional adjustment operations in making the bend.

It has also been found that the tube tends to be deformed during the bending operation by flattening or expanding laterally relative to the plane of the bend. Such deformation is very undesirable as it tends to weaken the tube and affects the cross sectional area of the flow passage.

A principal object of the applicants invention is to provide a tube bender having new and improved means for effectively preventing longitudinal movement of the tube during the bending operation.

Another object is to provide a tube bender having new and improved means for preventing undesirable flattening deformation of the tube being bent.

Still another object is to provide a new and improved tube bender provided with a sliding shoe element having substantially Aless tube contacting area than the tube contacting area of the tube bender mandrel.

A further object of the invention is to provide such a tube bender having tube retaining walls extending outwardly from the mandrel groove to grip tightly the tube when it tends to expand laterally during the bending operation.

Yet another object is to provide a tube bender having a mandrel and a sliding shoe element with complementary tube receiving grooves therein and with the mandrel groove having a semicircular bottom and parallel, straight sides.

A still further object is to provide a tube bender having a shoe adapted to engage a radially outer periphery of the tube over less than 180" extent to concentrate the the portion of the tube [having the greatest forces produced on the portion of the tube] having the greatest stresses produced therein during the bending operation.

Other features and advantages of this invention will` be apparent from the following description taken inconnection with the accompanying drawings, wherein:

Figure l is a fragmentary elevational view of a tube bender embodying the invention;

Figure 2 is an elevational View thereof with the parts thereof in a position assumed upon completion of ai tube bend;

Figure 3 is a sectional view, taken approximately alongy the line 3 3 of Figure l; and

Figure 4 is an end view of the tube bender with the;

parts in the position ofl Figure 2. I

In the exemplary embodiment of the invention as disclosed in the drawings, the tube bender generally designated 10 may be seen to comprise a mandrel 11 having a shoe element 12 pivotally secured thereto and adapted to move around the periphery of the mandrel. A handle 13 is iixedly secured to the mandrel and a hook 14 is pivotally mounted on the handle adjacent the mandrel for engaging a portion of the tube 20 to be bent for preventing lateral movement of the free end of the tube 20 away from handle 13 during the bending operation.

A new and improved tube receiving groove structure is provided in the periphery of the mandrel 11 and in* the face of shoe 12 comprising a recessed groove 11a inV the mandrel 11 and a shallow groove 12a in the shoe 12.

As will be brought out more clearly here following,V

4groove 11a acts effectively to prevent longitudinal movement `of tube 20 during the bending operation and the configuration of shallow groove 12a effectively minimizes frictional forces tending to move tube 20 longitudinally during the bending operation while providing an improved tube bending coaction.

Mandrel 11 comprises a generally cylindrical member having a bore 11b in which is freely pivotally carried a headed pin 11e. Shoe 12 is similarly provided with a bore 12b which carries a headed pin 12e. Extending between pins 11c and 12e is a link 15 which is adaptedV to allow movement of shoe 12 around the periphery of mandrel 11 with grooves 11a and 12a in complementary juxtaposed relationship. Pins 11e and 12e are swaged outwardly of link 15 to retain the'mandrel and shoe elements in assembled relationship. Extending from shoe 12 is a lever arm 12d permitting manual operation of the shoe.

As best seen in Figures 3 and 4, mandrel groove 11a, in cross section, is generally U-shaped having a semicircular inner surface 11d and parallel, planar outer surfaces 11e. Such structurey effectively constitutes a recessed, semi-cylindrical, annular groove having parallel .annular surfaces 11e extending outwardly therefrom tangential to the semi-cylindrical groove at the terminal edges thereof. Shoe groove 12a is made generally complementary to the mandrel groove/and extends substantially less than but suiliciently to engage the greater portion of tube 20 extending from mandrel groove 11a.

In utilizing my tube bender, a tube 20 is inserted into grooves 11a and 12a with shoe 12 positioned as seen in Figure l. Hook 14 is pivoted (to the left as seen in Figure 1) to engage the outer surface of tube 20 and prevent movement of the tube away from handle 13. Shoe 12 is then moved around the periphery of mandrel 11 through manual operation of lever arm 12d, while mandrel 11 is ixedly positoned by holding handle 13, until the desired bend in tube 20 is obtained. To assist in ascertaining the extent of any bend formed, mandrel 11 may be provided with a scale 11g showing the angular disposition of the portions of the periphery thereof.

The bending forces exerted on tube 20 yby shoe l2 Reissued Apr. 1, 1958 cause thetube to tend to expand laterally in mandrel groove 11a. However, iange surfaces 11e of the mandrel groove resist this lateral urging resulting in the tube being forced into tight holdingV engagement therewith. Thus, undesirable attening deformation of the tube and longitudinall movement of tube through groove 11a duringl the bending operation are prevented without the need of: additional tube constraining means. It should be noted, atthis point, that the functioning of my groove structure is antithetical to that of the conventional, soleiy semi-circular groove structure. In my device lateral expansion is constrained so as to hold the tube firmly in the groove, whereas in the conventional devices lateral expansion is not so checked and actually tends to draw the tube laterally from the groove (as the tube attens its cross-section changes from circular to somewhat elliptical and, thus thehalf of its minor axis extending toward' the groove bottom becomes less than the radius of the groove, thus eectingl a spacing of the tube from the groove surface).

AsV shallow groove 12a of shoe 12 provides a reduced area of sliding contact with tube 20, the frictional forces producedby the action ofthe shoe against the tube are correspondingly reduced', thus effectively minimizing the tendency of the shoe to move the tube longitudinaily during the bendingpoperation. Further, as the force of bend'- ing is applied primarily to the radially outerportion of the periphery of' the tube 20 where the greatest internal stresses are normally produced during the bending operation, the stretching effect, of the movement of shoe 12 against' tube 20 is concentrated where most desiredl rather than spread over the entire outer, semi-cylindrical surface of the tube as is done withshoes having grooves of 180 extent.

To remove the bent tube 20 from the tube bender 10, shoe 12 is pivoted to space groove 12a away from groove 11a and hook 14 pivoted to lose engagement with the outer surface of tube 20, allowing the bent tube. to be withdrawn forcibly from its gripped retention in mandrel groove 11a.

WhilerI have shown and described certain embodiments ofmy invention, it is to `be understood that it is capable of many modifications. Changes, therefore, inthe construction and arrangement may be made without departingfrom the spirit and scope of, the invention as d ened in the appended claims.

I claim:

1. A tube bender, of the character described, comprising; a rigidmandrel'provided with an annular, periphera-l'; groove having a U-shaped' transverse cross [sectional conguljationl section substantially the entire length thereof; a bending shoe carried by the mandrel to moye in juxtaposition to the mandrel periphery and havinga [an annularl groove arcuate in cross-section and of`less than 180` extent, said grooves having complementary tube receiving relationship; means for preventing lateral movement of one portion of a tube in said grooves; means for holding saidV mandrel; and means for moving said shoe.

2; A- tube bender, ofV theV character described, comprising: a rigid mandrel provided with an annular, peripheral groove, substantially the entire length thereo) being adapted to contact the surface of a tube over more than as measured around the tube axis [of the surface thereotj; a bending shoe carried by the mandrel to move in juxtaposition to the mandrel periphery and having a [an annular] groove arcuate in cross-section and adapted to contact less than 180 of the tube surface,rsaid grooves having complementary tube receivingrelationshipmeans for preventing movement. of a tube laterally from said grooves; means for holding saidmandrel; andl means for moving said shoe.

3. A tube bender of the character described, comprising: a mandrel provided with an annular, peripheral groove having over a substantial portion of the length thereof, including a portion intermediate the ends thereof, a transverse cross-section consisting of a semicircular inner portion and a rectangular, radially extending outer portion; a bending, shoe carried by the mandrel to move in juxtaposition to-y the mandrel' periphery; andA having; a,

[an arcuate, annularl groove arcuate in crossysection and of less than 180 extent, said grooves, having complementary tube receiving relationship; and means for preventing lateral movement of'one portionV of aV tube in saidV grooves.

4. A tube bender of-v the character descri-bed, comprising: a rigid mandrel provided with {having} a peripheral U-shaped] groove having a U-shaped transverse` cr0ss-section throughout o maior portion of the length thereof, a handle lixedly secured to said mandrel and having a hook movably mounted thereon for holding a tube toV be bent against movement away from said handle; a bending shoe having a shallow groove and a lever arm for manually operating said shoe; and link means for pivotally connecting said shoe to said mandrel with said grooves being positioned' toV form a tubereceiving, groove structure and allowing saidI shoe to be moved around the periphery of said-'mandrel' to` bend a tube therein.

5. In a tube bender ofthe character described, coacting mandrel and shoe elements, said'elementsj defining cooperatively a tube receivingy groove having; aA transverse cross-section characterized by an arcuate inner; portion, an arcuate outer portion, and av straight, parallel sided intermediate portion, said inner and intermediate portions having said cross-section throughout a maior portion of the length of. the groove.

References Cited inthe le-of thispatentor the original patent UNITED STATES PATENTS 2,127,185 Parker Aug. 16, 1938k 2,171,907 Beehler et al'. Sept. 5 1939 2,428,237 McIntosh Sept'. 30,y 1947 2,464,800 FranckV Mar. 22, 1949 2,757,562 Zales et al. Aug. 7, 1956 FOREIGN PATENTS 417,656 Great Britain Oct. 3 1934 464,413 Canada Apr. 1819'50

Images