US2901930A - Tube bending machines - Google Patents

Description

p 1959 s. WlLMAN 2,901,930

TUBE BEINDING MACHINES Filed Sept. 16, 1954 6 Sheets-Sheet 1 ATT RNEYS Sept. 1, 1959 s. WILMAN 2,901,930

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P 1959 s. WILMAN 2,901,930

TUBE BENDING MACHINES Filed Sept. 16, 1954 6 Sheets-Sheet 6 INVEN TOR SIGISMO/VD W/LMAN United States Patent Of'ice TUBE BENDING MACHINES Sigismund Wilman, Courbevoie, France Application September 16, 1954, Serial No. 456,508

Claims priority, application France August 10, 1954 8 Claims. (Cl. 80--11) In French Patent No. 1,016,517, filed on April 20, 1950, there is described a method of and a machine for the cold bending of tubular articles whereby the wall thickness of the tube to be bent is reduced in the region of the outer arc of the bent portion without appreciably compressing the side forming the inner arc.

This former patent describes a machine for carrying out the rolling operation which comprises a rolling-ball or rolling-wheel device adapted to be introduced into the tube to be rolled.

This machine offered a few drawbacks, notably in that the rolling balls or wheels had a small diameter in comparison with the rolling depth, so that the tube metal was caused to creep along a circular arc described by the rolling device and that the tubes were not bent according to a predetermined plane but were more or less spiraled or twisted. Moreover, the means provided in the aforesaid machine for adjusting the rolling depth was rather rudimentary and when it was contemplated to alter the throw of the device or to change the rolling radius, the operator was compelled to stop the machine to carry out the necessary adjustments, which involved a substantial loss of time and a poor machine output.

It is the chief object of the present invention to overcome these drawbacks by providing a machine having an article rolling operation using a single rolling-wheel of relatively large diameter with respect to the rolling depths. In fact, this diameter is greater than half the inner diameter of the tube to be rolled. With this novel arrangement the tube metal is not forced in a direction following the rolling arc since the rolling-wheel engages 'the metal with a very small angle. makes it possible to bend tubular articles in a predetermined plane without any spiralling or twisting thereof.

Furthermore, the machine according to this invention comprises two different adjustment means adapted to be operated either in unison or separately, i.e.: firstly, for adjusting the length of the rolling radius, and secondly for adjusting the position of the center of this rolling radius.

Finally, additional means are also provided in this machine whereby the adjustments indicated in the preceding paragraph may be carried out at will when the machine is in motion, without stopping it for altering the radius of curvature, thereby permitting a substantial increase in the efficiency of the machine.

Thus, this machine In order to afford a clearer understanding of the inplished by the machine illustrated in the other figures;

Figures 2 and 3 are a longitudinal axial section and a 2,901,930 Patented Sept. 1, 1959 cross-section, respectively, the latter being taken upon the line aa of Figure 2, showing the parts employed for rolling the tubular article 1 internally in view of bending same;

Figures 4 and 5 are a longitudinal axial section and a. cross-section, the latter being taken upon the line b-b of Figure 4, showing the mechanisms provided for effecting the aforesaid two adjustments;

Figure 6 is a cross-sectional view taken upon the line c--c of Figure 7 showing the carriage arrangement;

Figure 7 is a substantially complete view of the machine with parts shown in axial section; and

Figure 8 is a perspective view of the machine.

Referring now to the drawings, Figure 1 illustrates diagrammatically a tubular article 1 undergoing a bending operation by rolling in a machine constructed according to the teachings of this invention. Before the rolling operation the tube axis is located at centre 2. The tube is rolled along an offset circle by the rolling-wheel 3 rotating about its axis 4-, the latter describing in turn a circular path 5 around the rolling axis 6. Therefore, the outer end of the radius 7 extending from the axis 6 will describe a circular path 8 representing the roller inner surface. This circle is offset with respect to the circle 10 representing the inner surface of the tube before the rolling operation, the radius of this surface being indicated at 9.

Under these conditions, the axes passing through the centers 2 and 6 lie in the plane of curvature of the bent tube; in other words, if it is desired to thin out the tube wall on the side of greater radius of the bent portion without interfering with the radius of the opposed or inner side, both centers 2 and 6 will be located on the tube diameter passing through points 11 and 12, of which the former indicates the place where no rolling action is exerted on the tube wall while the other indicates the point of maximum rolling depth.

It is apparent from Figure 1 that under these conditions the distance from center 2 to center 6 is one-half of the rolling depth. To ensure a proper bending action it is necessary that the rolling action produced at point 11 be zero or substantially zero; in other words, the circular path 8 described by the outer end of radius 7 extending from center 6, and the circular path 10 described by the outer end of radius 9 extending from center 2 should be tangent or substantially tangent to each other at the theoretically stationary and unrolled point 11. In the first instance the unrolled portion if observed in the longitudinal direction will be a continuous line and in the other case a more or less wide surface.

To modify the rolling depth it is necessary to alter the distance between the centers 2 and 6; since the former is fixed this change can only be achieved by displacing the center -6 along the line 11-12. This displacement may be effected by means of any suitable mechanism, for example an eccentric motion.

If point 6 is lowered to increase the rolling depth at point 12, all the points positioned along the circle 8 will be lowered and therefore this circle will not be tangent to the initial circle 10 at point 11. In this case the unrolled strip left inside the bent tube will be too wide and if its width is equal to or greater than a quarter circle, the tube will be ovalized. Another drawback will be observed in the opposed direction if the point 6 is raised instead of being lowered. In this case, the rolling depth will be reduced at point 12 and increased at point 11 without any beneficial result.

The machine described herein by way of example and shown in the accompanying drawings is provided with adjustment means of the eccentric type, but the corre sponding adjustments may also be made through any other suitable mechanical means.

In Figures 2 and 3 of the drawings there is shown the rolling device with the relevant adjusting eccentric members. The rolling-wheel 3 is rotatably mounted for loose rotation on one end of a stub-shaft 13 around its axis 4, suitable bearing means, for example a needle-bearing 14, being interposed between the rolling-wheel 3 and stubshaft 13. This stub-shaft 13 is secured by means of a bolt 15 on one end of a main shaft 16 mounted for rotation about its axis 6 offset with respect to the axis 2 of the tubular article 1 to be bent. The rotary assembly is supported by a needle-bearing 17 for rotation inside a stationary member guided by a mandrel 18 corresponding in size to the inner surface of the still non-machined portion of tube 1 and engaging the latter with a clearance sufficient to enable the tube to engage the mandrel with the minimum resistance. The tube 1 is inserted between the stationary guide members 19, 20 forming together a rolling support.

For altering the position of center 6 relative to center 2 along the line 11--12 of Figure 1 a pair of eccentric sleeve members 21 and 22 positioned between the bearing 17 and mandrel 18 and adapted to rotate only in opposed directions are used, so that when these eccentric members are rotated the center 6 will be displaced vertically along the aforesaid line 11-12. In fact, if only one eccentric sleeve were provided, the axis 6 would not follow a rectilinear, vertical path but a circular path around the axis 2, and the point 12 of maximum rolling depth would be moved sidewise and the rolled tube spiralled or twisted as in the case of the aforesaid known machines.

Of course, the transverse displacement of the axis 6 is not attended by a similar displacement of the main shaft 16 throughout its length, as the opposite end of this shaft will not be moved in a direction across its axis. Nevertheless, the displacement of the rolling center, i.e. axis 6, is permitted by the relatively great length of the main shaft 16.

Figure 3 illustrates in cross-section the eccentric sleeves 21 and 22 in the positions corresponding to a relatively shallow rolling of a thin-walled tubular article. When the tube to be bent by rolling has a relatively thick wall it is necessary to carry out the rolling operation at a greater depth and therefore to rotate the eccentric sleeves 21, 22 to a greater extent in relation to each other.

The rolling radius 7 may be adjusted by rotating another or innermost eccentric sleeve 23 fitted around the rolling-wheel carrying stub-shaft 13 and surrounded in turn by the needle-bearing 17. By rotating this inner eccentric sleeve 23 relative to the parts 13, 14, 15, 16 of which it normally follows the rotational movements, it is possible to adjust the distance between centers 4 and 6, and to modify correspondingly the rolling radius. With this arrangement it is also possible to suppress the rolling action completely, for example when it is desired to pass progressively from a bent portion to a straight or unrolled portion of the tube, and to resume the rolling action at another point of the tube for forming another bend at a predetermined interval.

The eccentric sleeves 21, 22, 23 are controlled and rotate through a mechanism described hereafter and shown in longitudinal axial section in Figure 4 and in cross-section in Figure 5.

A case consisting essentially of two half- shells 28, 29 encloses the eccentric-sleeve adjusting device. This device is adapted notably to ensure the vertical displacement of the rolling circle 8 with respect to the tube center 2; for this purpose, the pair of eccentric sleeves 21, 22 are connected fast to tubular shafts 31, 32 respectively; on their ends opposed to those engaged by the eccentric sleeves these tubular shafts 31, 32 carry for rotation therewith bevel wheels 33, 34, respectively, as shown.

Both bevel wheels 33, 34 are in constant meshing engagement with an intermediate bevel pinion 35 rotating about a fixed axis; when. this pinion is rotated it causes 4 the bevel wheels 33, 34 which are of same size, to rotate at the same angular velocity but in opposed directions.

The bevel pinion 35 is rigid with a co-axial worm wheel 36 in constant meshing engagement with a worm 37 adapted to be actuated by a handwheel 84 (Figure 8).

As already pointed out hereinabove the inner eccentric sleeve 23 is movable about the rolling-wheel stub-shaft 13 and rigidly connected with a tubular transmission shaft 38 surrounding the main shaft 16. A ball-bearing or set of ball-bearings 39 are fitted adjacent to the end of the transmission tube 38 which is opposed to the end thereof which carries the inner sleeve 23, and these ballbearings carry a toothed wheel or annulus 40 having inner teeth meshing with a set of planet pinions 41; as shown in Figure 5, these planet pinions are also in meshing engagement with a sun wheel 42 rigid with the relevant end of the transmission tube 38. The toothed wheel 40 is also formed with a peripheral or outer set of teeth so as to constitute a worm-wheel for a purpose to be described presently.

Another toothed annulus 43 having the same set of teeth as the inner set carried by the toothed wheel 40 is clamped in a fixed position between the half- shells 28, 29 so as to be held against rotation. Another sun wheel 44 is keyed on the main shaft 16 adjacent to the end opposed to that carrying the rolling-wheel 3. Between the toothed annulus 43 and sun wheel 44 a set of planet pinions 45 of same dimensions as the aforesaid planet pinions 41 are provided, as shown.

Each planet pinion 45 meshing with the toothed annulus 43 has a shaft 45a co-axial to, and rotatably rigid with, another planet pinion 41 meshing with the first-mentioned toothed annulus 40 and each shaft 45a is mounted for loose rotation in a needle-bearing 46 fitted in a planetcarrier member 47 mounted in turn for free rotation on the main shaft 16 through the medium of ball-bearings 48.

The main shaft 16 is driven from a motor through the intermediary of a clutch member 49 and a sleeve 52 constituting the hub of the sun wheel 44 in the arrangement illustrated. Longitudinal stresses are supported by a thrust bearing 51 and lateral stresses by a rollerbearing 53.

When the machine has been properly adjusted both toothed annuli 40 and 43 are stationary.

Thus, the main driven shaft 16 is rigid with the innermost eccentric sleeve 23 through the sun wheel 44, the pair of planet pinions 41, 45, the sun wheel 42 and the transmission tubular shaft 38 so that the movement of rotation will be transmitted through these members from the clutch 49 to the rolling-wheel stub-shaft 13 and the eccentric sleeve 23 fitted therearound. Consequently, these driven members 13 and 23 will rotate in the same direction and at the same angular velocity so as to constantly remain in the same position relative to each other.

Obviously, this mechanism comprising toothed annuli, planet pinions and sunwheels would be useless if it were not required to alter the relative angular positions of member parts 13 and 23. Thus, its only purpose is to enable the operator to change at will and to set within very fine limits the angular positions of these two parts. This is achieved through the angular displacement of the adjustable annulus 40 relative to the stationary annulus 43 by means of a worm 50 meshing with outer teeth 65 of the annulus 40 and adapted to be actuated by hand even when the machine is running. This angular displacement does not interfere with the motion of the planet pinions which continue their rotational movement, but it brings about the relative angular displacement of main shaft 16 and transmission tube 38.

Figure 6 of the drawings shows in longitudinal axial section the carriage unit of the machine. A lower shaft 55 parallel to, and in the vertical plane of, the main shaft 16 carries a tubular worm 54 mounted for axial sliding movement on this lower shaft 55 through a longitudinal key 56 engaging a corresponding groove in worm 54 to prevent the latter from rotating about the shaft 55. Thus, the worm 54 and shaft 55 will rotate at the same angular velocity.

The lower shaft 55 is adapted, through the medium of the tubular worm 54, to drive a pair of lateral worm wheels 57, 58 formed on vertical shafts 59, 60 having keyed or formed on their upper ends spur pinions 61, 62, as shown. These spur pinions 61, 62 are in meshing engagement with corresponding carriage-driving racks 63, 64.

With this arrangement, the carriage '83 is adapted to be driven along the axes of shafts 16 and 55 and to push the tubular article 1 to be bent by rolling, suitable means being interposed between the tubular article 1 and the carriage 83 for securing the former to the latter so as to prevent the tubular article 1 from rotating relative to the carriage. The rate of feed of the carriage is set by means of the change-speed gear which is a mechanism already known per se and therefore requires no detailed description.

Figure 7 shows a complete view of the machine illustrating the greater part of its mechanisms in detail in order to facilitate the understanding of their relationship.

The frame structure of the machine comprises two separate sections. The rear half-frame structure 71 encloses the driving motor 72, the change-speed gear contained in a case 73 and the transmission for driving the planet pinions, together with the eccentric-adjustment mechanism, these last-mentioned transmission and mechanism being both enclosed in a common adjustment mechanism case 74 of which Figures 4 and 5 show the constructional details.

Another, front half-frame structure 75 carries the smooth guide-members or jaws 19, 20 receiving in sliding engagement the tubular article 1 to be bent by rolling. These guide members also act as die means and are adapted to withstand the rolling stress produced by the machine through the rolling wheel 3. Moreover, this front half-frame structure 75 is provided with a screw hoisting mechanism adapted to adjust the vertical position of a wheel or roller 76 designed to guide the already bent tube portion. This wheel or roller 76 is secured on a table 77 mounted for vertical sliding movement on the front half-frame structure 75. The screw hoisting mechanism provided for this purpose comprises a vertical screw shaft 78 having keyed thereon a worm wheel 79 meshing with a horizontal worm 80 adapted to be actuated by means of a hand crank 86.

Roller 76 is provided principally to permit the measuring of the radius of bending of the tube. If, for example, it is desired to bend the tube with a given radius, the level of table 77 is adjusted to a corresponding height and the position of the bent tube relative to said roller indicates whether or not the tube is bent with the desired radius. Thus, if the tube is not in contact with roller 76 as adjusted, the radius of the bend is too small. The roller 76 is not primarily intended for bending the tube, but should the tube bear too heavily on said roller, the roller may have a small correcting effect by causing a small reduction of the radius of the bend.

At any rate the radius of curvature cannot be reduced to a substantial degree by means of this roller 76 alone, as the latter is intended primarily to keep the tubular article exactly in the plane of bending. Therefore, when the measurement of the radius of curvature has been accomplished, this roller 76 may be removed without any inconvenience; it is even preferable to remove it when frequent changes in the plane of bending are to be effected.

Both half-frame structures 71, 75 are rigidly secured or embedded in the concrete floor at an adequate distance from each other, according to the maximum length of the tubular articles to be bent.

To ensure a satisfactory and accurate operation of the machine, the longitudinal axes of the various mechanisms constituting the machine must be strictly parallel and aligned with one another. The proper spacing between the half-frame structures 71 and 75 is provided and maintained at their upper portions by the pair of carriagedriving racks 63, 64 and at their lower portions by stiffening and spacing braces 81, 82 the exact length of which should be adjusted accurately before the half-frame structures are definitely embedded in position so as to provide the required parallelism.

The carriage 83 is slidably guided at its upper portion by the racks 63, 64 and at its lower portion by the feed shaft 55, between the front and rear half-frame structures 71, 75.

The machine according to this invention is characterized by the following substantial improvements:

(i) Various adjustments can be carried out during the operation of the machine, notably the adjustment of the degree of eccentricity or throw of the rolling-wheel axis relative to the axis of the tubular article to be bent, this adjustment being effected by actuating the handwheel 84 controlling the worm 37, as shown in detail in Figure 4;

(ii) Adjustment of the rolling radius by means of the handwheel 85 rigid with worm 50 driving the annulus 40 of the planetary gear shown in Figure 4;

(iii) Adjustment of the radius of curvature of the tubular article to be bent, by means of the crank 86 rigid with worm 80;

(iv) The cooperating guide members 19, 20 can be tightened during the operation of the machine for adjusting the length of the arc to be rolled; this type of adjustment already described in the aforesaid French patent application may be combined with the adjustment afforded by the arrangement of this invention;

(v) These various adjustments may be combined in accordance with this invention for changing at will the radius of curvature or bending of the tubular article, without stopping the machine;

(vi) With the machine according to this invention it is also possible to alter the plane of bending at will. On the other hand, an 8 may be formed in a tubular article without removing the latter from the machine. Besides, the plane of bending may be altered to the desired angular value by simply unclamping the tube on the carriage 83 and lowering (or even removing completely, if necessary) the table 77 carrying the roller 76, and subsequently rotating the tubular article to the desired angular extent, for example when it is contemplated to bend it to an S shape, and clamping the tube again on the carriage before re-starting the machine.

While the above description refers to a specific embodiment of a tube bending machine constructed in accordance with the teachings of this invention, it will be readily apparent to anybody conversant with the art that many modifications may be brought thereto without departing from the spirit and scope of the invention as pointed out in the appended claims.

What I claim is:

l. A machine for bending a tubular article through a cold-rolling operation comprising supporting guide members for receiving the tubular article therethrough, a driven shaft positioned for extending in the bore of said tubular article, a guiding mandrel for supporting one end of said shaft positioned between said guide members, a rolling wheel having a diameter smaller than the inner diameter of said tubular article and being mounted for loose rotation on said shaft about an axis offset relative to the axis of said tubular article for contacting and thinning said tubular article in the region of its outer are of bending thereby causing said article to bend, means for adjusting the position of said driven shaft and means extending through said tubular article and drivingly op erating said shaft adjusting means for on the one hand altering the throw between the axis of rotation of said shaft and the axis of said tubular article and on the other hand between said axis of rotation of said shaft and the axis of rotation of said rolling wheel.

2. A machine according to claim 1, including means for adjusting the axis of said rolling wheel relative to the axis of said tubular article, and separate means for adjusting the position of said rolling wheel axis relative to the axis of the surface of said article contacted by said rolling wheel.

3. A machine according to claim 1 wherein said adjusting means includes an eccentric sleeve member having its bore in engagement with said driven shaft and adapted to rotate therewith at the same angular velocity after the mutual angular positions of said shaft and said eccentric sleeve have been properly adjusted for altering the distance between said rolling wheel axis and the axis of the surface of said tubular article contacted by said rolling wheel.

4. A machine according to claim 1 wherein said adjusting means includes an eccentric sleeve positioned between said driven shaft and said mandrel for modifying the distance between said rolling wheel axis and the axis of the surface of said tubular article contacted by said rolling wheel, a tubular transmission shaft mounted on said driven shaft and carrying said eccentric sleeve member, a sun wheel rigidly mounted on said tubular transmission shaft, pinions in meshed engagement with said sun wheel, a planetary gear operatively connected with said pinions, a toothed annulus in driving connection with said planetary gear and means provided for rotating said annulus and thereby rotating said sleeve for adjusting the position of said rolling wheel axis.

5. A machine according to claim 1 wherein said adjusting means includes an eccentric sleeve positioned between said driven shaft and said mandrel for modifying the distance between said rolling wheel axis and the axis of the surface of said tubular article contacted by said rolling wheel, a tubular transmission shaft mounted on said driven shaft and carrying said eccentric sleeve member, a sun wheel rigidly mounted on said tubular trans mission shaft, a planet carrier member mounted on said driven shaft for free rotation thereon, a set of pinions in meshed engagement with said sun wheel, a plurality of shafts each fixedly connected to one of said pinions and mounted on said planet carrier member for free rotation thereon, a second set of pinions each fixedly mounted on one of said shafts with a pinion of said first mentioned set, a second sun wheel fixedly mounted on said driven shaft, a fixedly toothed annulus having said second set of pinions in meshed engagement therewith whereby said driven shaft and said sleeve will rotate in the same direction and at the same angular velocity and means provided for rotating said first mentioned set of pinions for changing the position of said sleeve relative to said driven shaft.

6. A machine according to claim 1 wherein said adjusting means includes an eccentric sleeve member mounted on said rolling wheel driving shaft and adapted to rotate therewith at the same angular velocity, a second eccentric sleeve member, a bearing having said first mentioned sleeve rotatably mounted therein, the outer race of said bearing being provided by the bore of said second sleeve, a third eccentric sleeve surrounding said second sleeve, means for rotating said second and third sleeves when desired for adjusting the relative throw of said axis of rotation of said shaft and said tube axis and means for changing the relative angular position of said first mentioned sleeve and said driven shaft modifying the throw between said shaft axis of rotation and the axis of rotation of said rolling wheel.

7. A machine according to claim 1 wherein said adjusting means includes an eccentric sleeve member mounted on said rolling wheel driving shaft and adapted to rotate therewith at the same angular velocity, a second eccentric sleeve member, a bearing having said first mentioned sleeve rotatably mounted therein, the outer race of said bearing being provided by the bore of said second sleeve, a third eccentric sleeve surrounding said second sleeve, a pair of concentric tubular transmission shafts carrying at one end said second and third eccentric sleeve respectively, a pair of parallel and aligned bevel wheels each rigid with one of said pair of tubular shafts, a bevel pinion having its axis at right angles to said wheels and meshing therewith for imparting angular displacement of the same value but opposite directions to said bevel wheels and therefore said second and third sleeve members for adjusting the relative throw of said axis of rotation of said shaft and said tube axis and means for changing the relative angular position of said first mentioned sleeve and said driven shaft modifying the throw between said shaft axis of rotation and the axis of rotation of said rolling wheel.

8. A machine according to claim 1 wherein a presser roller is mounted adjacent said mandrel on the article emerging side thereof and adapted to co-act with and support the convex portion of the bend in said article and means are provided for adjusting the position of said roller.

No references cited.

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