US1721964A

US1721964A - Method of and apparatus for bending structural shapes

Info

Publication number: US1721964A
Application number: US131623A
Authority: US
Inventors: George R Mcalfenan
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-08-26
Filing date: 1926-08-26
Publication date: 1929-07-23
Anticipated expiration: 1946-07-23

Description

ly 23, 1929- G. R. M ALEENAN' 1,721,964

METHOD OF AND APPARATUS FOR BENDING' STRUCTURAL SHAPES Riled' Aug. 26. 1926 2 Sheets-Shee 1 gwuento ablio'zuug July 23, 1929. e. R. M ALEENAN 1,721,964

METHOD OF AND APPARATUS FOR BENDING STRUCTURAL SHAPES Filed Aug. 26. 1926 2 Sheets-Sheet 2 nientetl July 23,

warren stares GEGRGE Pt. MQALEENAN, OF PITTSBURGH, PENNSYLVANIA.

METHOD OF AND APPARATUS FOR BENDING STRUCTURAL SHAPES.

Application filed August 26, 1926. .Serial' No. 131,623.

This invention relates to the art of bending structural units or shapes, such as Ts, angles, Z-bars, channels, I-beams, and the like, and consists in the improved method and apparatus for carrying it out as hereinafter described.

In bending a curve in a straight piece of flanged structural metal, such for instance as an angle bar, the bar has a tendency to twist about its longitudinal axis, so that the sides of the angle do not lie in continuous correspending planes throughout the length of the bar in the same angular relation as when straight. The metal also has a tendency to buckle under some conditions, and in some places, While in other places, the metal is apt to break or tear under the strains.

In bending structural shapes where the line 'or plane of bending force is parallel with the web member, there is a continuous tendency to buckle'under compression strains and to stretch under tension strains, at one side orthe other of an intermediate neutral bending line. T fhere the shape to be bent involves the generation of such strains in a web member, and also similar strains in one or more flange members, it is impossible to effect successful bending, unless continuous opposition to the several distorting tendencies noted is interposed during the application of bending force.

Machines utilizing bending rolls have here- I tofore been used with considerable success,

and are now generally employed for such kind of work. Machines of this kind, however, are expensive, they operate slowly, and are not dependable for absolute accuracy, especially in their treatment of the terminals of the bar or other member.

Bending has also been accomplished by the intermittent application of bending force, as carried out in abulldozer, but smooth accurate bending is impossible even by an experienced operator, with only approximately true bending under most favorable conditions, while the operation with such a machine, especially for bending long curves, is very slow. r

With my presentinvention, bars or shapes of any desired length may be bent accurately to practically any desired reasonable curvature, and straight angle or other flanged bars nay be easily, accurately and quickly bent into semi-circular or other desired curved shapes. The production of such curved bars sition;

or shapes of continuously uniform curvature, and Without distortion, can be effected in large numbers and with absolute assurance that all pieces will correspond.

1n carrying out my invention, I utilize. means for effecting bending force through suitable clamping dies, in one plane, With cooperating resistance and confining force-applying means operating in another plane, usually at right angles thereto.

The invention also involves means for conlining the several Web and flange members of various shapes, While undergoing the bending'treatmcnt, so as to completely counteract and resist any tendency to buckling or dis tortion, and at the same time retaining the several members during the application of compressive or tensile exerting strains throughout the portionof the bar under treatment. i

The invention will be readily understood by reference to the accompanying drawings, in which: 7 H 1 Fig. 1 is a somewhat diagrammatic view of a standard press adapted to. carry out the invention;

Fig. 2 is a diagrammatic plan View, enlarged, showing the bending dies in closed po- Fig. 3is a similar View, showing the dies open;

Fig. 4 is a sectional detail view, on theline IVIV of Fig. 2, showing the bending and clamping dies in closed position, for operation on a T-bar;

,Fig. 5 is a similar View showing the bend- .ing and clamping dies in closed position,for

operation on an angle bar; 1 v Fig. 6 is a similar View, showing the bending and clamping dies in closed position, for operation on a Z-bar;

Fig. 7 is a similar View, showing the bending and clamping dies in closed position, for operation on a channel bar;

Fig. 8 is a similar View, showing the bending and clamping dies in closed position, for operation on an I-beam. v

In thedrawings, A is a hydraulic or other press, of any suitable standard or preferred design, having a vertical cylinder 5 and a ram or plunger 6, and a horizontal cylinder 7 with a mm or plunger 8, of usual construction. Vertically acting cylinder 5 is controlled by a valve 9, and horizontally operating cylinder 7 is similarly. controlled by a valve 10, with suitable connections, as shown, for advancing and retracting the plunger-s in the usual way.

Mounted upon and rigidly secured to the under frame a of the machine, is an L-shaped anvil block 11, adapted to receive and support the relatively stationary and

movable dies

12 and 13 respectively. Die 12 is fixedly secured by bolts or otherwise, while die 13 is similarly connected with the head 14 of plunger 8, for pressing and retracting movement. Each die is curved conformably to the desired curvature of the member to be bent, die 12 being preferably concave, and die 13 correspondingly eonvexed, as in Fig. 2.

When designed for the purpose of bending T shapes, each of said dies is recessed, as at 15, for reception of the oppositely extending flanges of the T, so that, when gripped between the dies, the upper surface of said flanges will be substantially flush with the upper surfaces of

dies

12 and 13.

Depending from the vertically acting plunger 6 of cylinder 5, is a heavy rigid platen or pressing head 16, the lower surface of which is substantially CO-QXtCnSlVG with the upper surface areas of

dies

12 and 13, parallel therewith, and adapted to be lowered thereon, and upon the surface of the T flanges, for close contact therewith, on a common meeting plane.

' It will be understood that whatever the length of the unit being bent, it is passed progressively in stages across and between

dies

12 and 13, for sectional bending, so as to-produce a continuously curved resulting bar.

That is to say, the end portion of a straight bar is first introduced between

dies

12 and 13 throughout their length; die 13 is then advanced in connection with the lowering of platen 16, for bending and clamping, with resulting curvature of the section being treated.

The die 13 is then retracted, with corresponding raising of the platen, when the next adjacent straight section is advanced, theoperation being repeated, and thus carried out for the full length of the bar.

If desired, a slight overlap of the previously bent section where it merges into the straight section may be utilized within the exit end of the dies 12--13, thus avoiding the possibility of any undesirable kink or irregularity.

v In bending an angle bar, the

dies

12 and 13 are shaped conformably, but die 13 may be used with the flange receiving recess 15 on either its upper or lower side. When uti lized on the upper side, its action will be substantially like that above described as to T- bars, with the flange confined between such recess and the lower face of platen 16.

In the construction as shown, however, die 13 is reversed, and the flange of the angle bar makes contact with the lower corresponding flat face 17 of block 11. With either arrange ment, the flange will be positively confined within its own cross sectional dimensions against buckling or other distortion throughout the entire bending operation.

In bending Z-bars, as illustrated in Fig. 6, the

dies

12 and 13 are L-shaped in cross section, as shown, providing web contacting faces 18 and 19 respectively, which, under the pressure of platen 16, will effect the same confining maintenance of the original plane of the web, against such distortion, and during bending of the flanges'and the web by action of die 13.

The dies in such construction grip the oppositely extending flanges of the Z-bar between them in the same general manner as already described as to the web member of the T, the upper flange extending up to the plane of the upper surface of the dies. It is, therefore, also subject to the pressing action of platen 1.6, while the downwardly extending flange is firmly and positively gripped be tween the laterally acting dies, as described. In bending channel shapes, as in Fig. 7, the concave die 12 and convex die 13 operate in the same manner to grip between them one flange of the channel, with its web lying across the suitably recessed upper plane face of die 13, as at 20. The other flange extends downwardly within a suitably dimensioned transverse clearance opening 21, and against the outer wall 22 thereof, properly positioned to receive the said flange for effective resistagce thereto, as-the die is moved inwardly.

In' both inward and outward movement, transverse cavity 21 provides ample clearance for bending and for shifting of the bar across thedies, for the next operation. The clamping conditions provided for effectively hold the web and flange members of the channel against distortion under pressing action of platen 16 during the bending operation, in the same'way as with the other shapes described.

In bending I-beams, I preferably utilize a double set of upper and lower stationary dies ill) 12 and 13 respectively, in all essential respects like the

dies

12 and 13 above described, as utilized for channel bar bending. In other words, an I-beam being, in eflect, a double channel, the gripping of its web involves the utilization of a second interposed bending die having also a clamping action between the web and platen 16.

The depth of the clearance openings 21, both above and below the web, is substan tially the same as the width of the flange from the center of the web to the outer edge of the flange in opposite directions. flange, toward the actuating plunger 8, there fore, is continuously pressed by such flangeengaging portion of dies 13 so that, when the opposite flanges are tightly clamped metween the meeting faces of the movable and The inner stationary dies respectively, and under the holding'action of platen 16, the several flanges and also the'web of the I-beam will be tightly clamped against distortion.

It will be observed that in all cases the flange member or members and the web mem her as well are confined between both the contacting bending and clamping faces in directions both parallel with and transverse to the lines of force.

Also, that in introducing the bar between the bending dies, it assumes the relation of a tangent to the convex die and that of a chord of the arc of curvature of the concave die.

Proper bending action, whether of the flange members or of the web members, and whether croswise or edgewise, is thus pro vided for during continuous tight clamping conditions, preventing any undesired dis placement, crowding, buckling, or rupture of the metal under either compressive or tension strains.

It will be understood that the lateral shifting of the member being treated is easily accomplished by hand or by suitable pushing mechanism, dependent upon the degree of friction interposed between the blank and the dies.

Also, that if desirable or necessary, the member to be bent may be either partially or completely acted on during a first or preliminary passage through the dies, followed by a second or final treatment in stages as described, to bring the shape to its desired final form, and with complete elimination of irregularities.

The design or detail construction of the machine, and the exact or particular manner of its operation, is not necessarily confined to the construction shown and described, but may be changed or varied, either as to such construction or use, by the skilled mechanic or operator, and all such changes are to be understood as within the scope of the appended claims.

What I claim is:

1. The method of bending a structural flanged member having a divergently disposed portion in cross section consisting in placing the member while straight between co-acting clamping and bending dies and imparting bending movement to the member and its diverging portion in one direction of movement while exerting opposing resistance to the member and its diverging portion and against the outer faces of the dies across such direction of movement, while maintaining clamping resistance against the flanged portion and divergently disposed portion respectively.

2. The method of bending a structural flanged member having a divergently disposed portion in cross section consisting in placing the member while straight between co-acting clamping and bending dies and imparting bending movement to the member and its diverging portion in one direction of movement while exerting opposing adjustable resistance tothe member and its diverg- 'ing portion and against the outer faces of the dies across such direction of movement while mamtainmg clamplng reslstance against the flanged portion and divergently disposed portion respectively. 7

3. The method of bending a structural bar having a web member and a flange member consisting in placing a straight bar between co-actingbendingdies shaped to fit the deagainst the fiange'member and opposite faces of said dies, while maintaining clamping resistance against the flange member and the web member respectively.

4. The method of bending a structural bar to curved shape consisting in simultaneously imparting transverse bending strains to all members of the bar by confining and pressureexerting dies curved to the arc of the curve to be formed and adapted to exert pressure directly against the face of one member, while holding and confining the other member and said dies between pressure exerting faces by action of means movable in a direction across the plane of movement of the bending action, with continuous action of confining resistance upon all members of the bar. I

5. The method of curving flanged structural bars consisting in imparting transverse bending strains to aportion of the barby dies curved to the arc to which the curve of the bar is to be formed and with respect to one of which the section to be bent forms a chord of the arc of curvature, while holding one portion of that section of the bar by pressure at right angles to the plane of movement of the transverse strains in a recess in one of the dies the shape and size of which is just sufficient for the portion to fit snugly therein when the bar is bent, and then relieving the bar and subjecting a contiguous portion thereof to a similar operation until the desired length of bar has been curved.

6. The method of curving flanged structural bars consisting in imparting transverse bending strains to a portion of the bar by dies curved to the arc to which the curve of the bar is to be formed and with respect to one of which the section to be bent forms a chord of the are of curvature, while holding the flange of that section of the bar by pressure at right angles to the plane of movement of the transverse strains in a recess in one of the dies the shape and sizeof which is just sufiicient for the flange to fit snugly therein when the bar is bent, and then relieving the bar and subjecting a contiguous portion openings for the several portions of the bar when the dies are closed adapted to embrace and bend the bar in one direction of movement, and movable means for exerting opposing and confining resistance to the bar and the dies in a direction transverse to such direction.

7 8. Apparatus for bending a structural flanged bar consisting of a die support, a curved stationary die thereon, a co-acting curved movable die on the die support having clearance openings for different portions 0 the bar when the dies are closed, means for moving it towards and from the stationary die, and a clamping platen operable at right angles to the plane of movement of the movable die and close to the outer surface thereof for confining portions of the bar during the bending operation.

9. Apparatus for bending a structural flanged bar consisting of a die support, a curved stationary die thereon, a co-acting curved movable die on the die support having means for moving it towards and from the stationary die, said dies having clearance spaces in variously different planes for embracing engagement of portions of the bar, a clamping platen operable at right angles to the plane of movement of the movable die and having a plane surface for contact against the dies for confining portions of the bar between it and the die support against buckling during the bending operation, and means for actuating the platen.

10. Apparatus for bending curves in angle bars which consists of a press having two plungers movable at an angle to each other, a curved die carried by one plunger, a pressure plate carried by the other plunger, a second curved die for cooperation with the :first, one of said dies having a recess to receive the flange of the bar to be bent, said pressure plate having a plane bearing surface being so positioned as to apply a holding pressure on a flange of a bar when received in said die, whereby the pressure plate may be utilized to resist the twisting movements on the flange when the bar is curved.

11. Apparatus for bending curved angle 'bars comprising a press having two plungers movable at an angle to eachother, a die hold-' ing block in juxtaposition thereto, a pressing plate carried by one plunger, a die carried by the other plunger having an arcuately curved pressing surface correspondingto the curvature to which the bar is to be bent, at second die on said block for cooperation with the first and having a correspondingly curved pressing surface concentric with the curved surface of the first die, one of the dies having a recess the-rein of a depth equal to the thickness of the flange of the bar to be curved and of a width substantially equal to the width of the flange, said recess being concentrically formed with relation to the curved surface of the die on which it is formed, said pressing plate being power actuated and designed to cooperate with the recessed die for applying pressure to opposite sides of the flange of the bar being bent.

In testimony whereof I hereunto affix my signature.

GEORGE R. 'MGALEENAN.