A swinging self-positioning support for pipe bending machines

Abstract: A pipe bending machine comprising a bending assembly (1) and a support arm (2), wherein said arm is pivotedly supported swingingly relative to the bending assembly through a pivot (6), slidably supported along a stem (7) on the axis passing through the centre of rotation of the matrix and the centre of swinging of the countermatrix assembly, so as to automatically position itself on the zero.

Description: The present invention relates to a pipe bending machine according to the preamble of claim 1 (see for example DE-A-4 329 567). More particularly, the present invention relates to the pipe bending machines having the bending system with the countermatrix assembly which swings up to the position in which the thrust forces of the matrix and of the countermatrix go into contrast on the pipe to be bent in the bend start step. With the known pipe bending machines with the swinging countermatrix system the supporting of the pipe takes place for instance on a stand or on a plane, whereupon the pipe rests, or even the pipe is cantilevered between the matrix and the countermatrix, without any support,with a difficulty in executing the bending operation. Moreover, with these solutions there isn't any possibility to mount a member for controlling the pipe in its shifting and rotation in the bending step, such as made by the mandrel that, on the contrary, is mounted on the arm for supporting the pipe in the systems of the type with a non-swinging countermatrix assembly such as those which the present invention relates to, nor to control the "zero" fixed point of the radial motion of the pipe and then of the support. General object of the present invention is to provide, for a pipe bending machine of the aforesaid type, an arm for supporting the pipe, so as to be able to endow such a machine with a mandrel for guiding and controlling the pipe in a bending step. However, in the pipe bending machines of the type which the present invention relates to, the bend start swinging of the countermatrix assembly results in a corresponding angular displacement of the pipe to be bent before reaching the true bending step. The main object of the present invention is thus to provide an arm for supporting for such a type of machine that is able to follow such a swinging of the pipe in the bend start step with pivoting on the zero, and that, at the same time, is rigid and responsible to the motion of the pipe enough to the end of precision. By "zero" it is meant herein the intersection of the axis of the pipe to be bent with the straight line through the centres of the rotation of the matrix and of the swinging of the countermatrix assembly. Such an object is reached, according to the teaching of the present invention, by a pipe bending machine according to claim 1. The dependent claims define preferred embodiments of the invention. The so configured machine, i.e. the machine with pivoting about the zero, allows in an absolute way not to vary the distance "x" between the zero point and the mandrel in the step of the self-positioning of the swinging support. Said distance is necessary to the end of being able to predeterminate linear ledges of the mandrel for the execution of a piece according to a drawing. Moreover, as the swinging support pivoted on the axis through the zero slides on the perpendicular of the axis through the centre of the matrix and the centre of the swinging of the countermatrix, that condition allows one to leave the work field without removing the piupe from the machine to allow the substitution of the matrix with another one of a different radius as required by the drawing, without losing the heights preset on the linear and rotational axes. With such a structure one has the advantage that a support arm goes to make up a mere means for supporting; it has not to load itself with the forces that arise in the step of the start of the bend, and a light structure can be foreseen for it. The machines made according to the teaching of the present invention, the performance being the same as those according to prior art of the rigid type, i.e. with a non-swinging countermatrix assembly and a support arm which is fixed in a rigid way, even if positionable, have a weight reduced from the order of quintals, to the order of tens of kilograms, in that the side contrast thrust in the step of bending in the swinging system is entirely supported by the swinging countermatrix assembly. Following the swinging of the countermatrix assembly and the consequent one of the pipe axis, the support arm itself goes to position itself according to what will be the configuration of the machine in the true bend start step. The present invention will be best understood based upon the following detailed description of its preferred embodiment, given only as a matter of example, with reference to the accompanying drawings, wherein: FIGURE 1 is a top view and FIGURE 2 is a side view of the pipe bending machine according to a preferred embodiment of the present invention. It comprises a bending assembly 1 and a pipe support arm 2, on which a mandrel 3 is positionable. The assembly 1 comprises a shoulder groove pulley matrix 4 and a countermatrix 5. The support arm 2 is articulated in a swinging way to the bending assembly 1 through a first pivot 6, which has its axis integram with the bending assembly and is cantilevered relative to the countermatrix assembly through a stem 7 along which it is slidably supported by means of a block 8, whereinto the first pivot 6 is directly mounted. The stem 7 is ended beyond the block 8 by a circular ledge 7'. With this construction the pivot 6 always finds itself on the perpendicular of the axis through the centre of the matrix-centre of swinging of the countermatrix group and on the axis of the pipe under bending. Therefore the arm is always pivoted to an end on this pivot. Moreover, it is swingingly supported by two links 9, 10 connected with each other and the second one with the arm through pivots, a second and a third one, 11, 12. The link 9 with an end is connected fixedly to the machine body in a fixed way, for instance by means of bolts 17, and by the other end it rests on the ground through adjustable screws 18 for the levelling. The function of this link 9 is to ensure stability to the machine and the length of the latter as a function of the length of the arm 2. With this constitution the arm is perfectly able to follow the swinging of bend start due to the swinging of the countermatrix assembly. The positioning of the pivot 6 is a function of the bending radius one wants to impress to the pipe, i.e. of the radius of the matrix. A screw 5' can access the surface of the stem 7, screwing itself in a respective hollow, to fix the correct position of the sliding of the first pivot 6. The aforesaid circular ledge 7' provides for avoiding the sliding of the block 8 out of the stem 7. The construction is completed by rollers 13 shaped as a function of the pipe or beam to be guided and supported on both the vertical and the horizontal axes that are arranged at the pivoting end of the support arm 2, which rollers are handle-adjustable as a function of the diametre of the pipe. Moreover, the arm 2 is supported on the link 10 through the linear guide of rollers 16 (see FIGURE 2), which render the pivoting motion on the third pivot 12 possible. The swinging of the link 10 is restricted by the stops made up by rollers 15 that slide fixably in respective slots of a caliper 15', centred on the second pivot 11 to the end of restricting the idle stroke of said link. The present invention has been described and depicted with reference to a preferred embodiment, but it is to be expressely understood that variations can be made without thereby departing from the scope of the invention as defined by the appended claims. For instance, the support arm could also be supported at the not pivoted end on a rolling wheel on the ground. Still, the motion assembly 10-11-12 could be duplicated, triplicated or generally multiplied in order to support higher arms and weights.

Claims: A pipe bending machine comprising a bending assembly (1) provided with a pulley matrix (4) and a countermatrix assembly (5), a support arm (2) and a mandrel (3) positionable on the support arm (2) for positioning a pipe to be bent, characterized in that said arm (2) is pivotedly supported swingingly with respect to the bending assembly (1) through a first pivot (6) slidably supported along a stem (7) along the axis passing through the centre of rotation of the matrix (4) and the centre of the swinging of the countermatrix assembly (5), so as to automatically position itself on this axis on the vertical through the axis of the pipe to be bent, i.e. on the zero point, so as not to vary the distance between the zero point and the mandrel (3) in the self-positioning step of the swinging support arm (2). A pipe bending machine according to claim 1, further characterized in that said support arm (2) is supported by two links (9, 10), the one fixedly united (17) to the bending assembly (1), the other one pivoted through a third pivot (12) with the arm (2) itself, and pivoted with each other through a second pivot (11), whereby in order to compensate for the swinging of the second link (10) the third pivot (12) is connected with the support arm through means that allow for it a linear reciprocating and a rotary motion relative to the arm itself, the fixed link (9) ensuring stability for the machine and its length being a function of the length of the arm (2). A pipe bending machine according to claim 1 or 2, characterized in that it comprises adjustable rollers (13) for aligning the pipe or beam to be bent on the axis of the arm (2), at the pivoting end of the arm (2). A pipe bending machine according to claim 3, characterized in that said aligning rollers (13) have a groove shaped in such a manner as to restrict the pipe horizontally and vertically. A pipe bending machine according to claims 2 to 4, characterized in that it comprises slot idle stroke stops (15) for the angular stroke of the second link (10), fixable in position in a caliper centred on said second pivot (11).

Inventors: CAPORUSSO ALESSANDRO, CAPORUSSO MARIO, CAPORUSSO, ALESSANDRO, CAPORUSSO, MARIO
Applicants: CML COSTR MECC LIRI SRL, C.M.L. COSTRUZIONI MECCANICHE LIRI S.R.L.
Application year: 1996
Main classification: B21D7
IPC codes: B21D7