US2986195A

US2986195A - Tube bending machines

Info

Publication number: US2986195A
Application number: US596561A
Authority: US
Inventors: Alfred R Landis
Original assignee: IMP Eastman Corp
Current assignee: IMP Eastman Corp
Priority date: 1956-07-09
Filing date: 1956-07-09
Publication date: 1961-05-30
Anticipated expiration: 1978-05-30

Description

May 30, 1961 A. R. LANDIS TUBE BENDING MACHINES Filed July 9, 1956 5 Sheets-Sheet l FIGZ, 90

May 30, 1961 A. R. LANDIS TUBE BENDING MACHINES 3 Sheets-Sheet 2 Filed July 9, 1956 I Hull m FIG.4.

Ma /r741?" A 4 rmw Kama/6 I Ween 0 s.

y 1961 A. R. LANDIS 2,986,195

TUBE BENDING MACHINES Filed July 9, 1956 5 Sheets-Sheet 3 3y MM TUBE BENDING MACHINES Alfred R. Landis, St. Johns Station, Mo., asslgnor, by mesne assignments, to Imperial-Eastman Corporation, Chicago, 111., a corporation of Illinois Filed July 9, 1956, Ser. No. 596,561

3 Claims. (Cl. 153-40) impractical in small sizes (for example Vs inch OD), .and tube bending machines designed forsmall sizes of tubing have not heretofore been readily adaptable to larger sizes (for example inch O.D.).

One of the objects of this invention is to provide a tube bending machine in which the tendency of thin-walled tubing being bent tocollapse is overcome.

Another object is to provide a compact tube bending machine which may be quickly and easily adapted to bend tubes of various different diameters.

Still another object of this invention is to provide a tube bending machine capable of bending tubing of both large and small diameter.

Still another object of this invention is to provide a tube bending machine with a rotating radius form block which is positively maintained against disalignment with a complementary form shoe.

Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.

In accordance with this invention, generally stated, a

tube bending machine is provided with a rotating radius form block and a rectilinearly moving complementary form shoe, each having a groove which embraces respectively diametrically opposite sides of a tube being bent. At least one of the grooves is circularly arcuate and has a radius less than the radius of the tube being bent. Preferably, the radius form block is mounted on a spindle which is rotated by a bull wheel from. which the spindle can be readily pulled. A pinion, mounted on the spindle, serves to drive a rack plate upon which a form shoe is mounted in such a way that it can be readily removed and replaced.

The end of the spindle opposite the.bull wheel is journaled in a hearing which is arranged to be swung out of the way to permit the spindle to be removed from the bull wheel. The bearing counteracts the tendency of the spindle to disalignment under the thrust of a tube being bent.

The hull. wheel is driven by a worm gear which may be rotated by turning either of .two shafts. extending at United States Patent 2,986,195 e e y 21??? right angles to one another and which may provide ferent gear ratios.

Especially in bending thin-walled tubing of small diameter, provision is made for positively inter-engaging the radiusform block and the form shoe to ensure align.- ment of the forming grooves.

In the drawing,

Figure 1 is a top plan view of a tube bending machine constructed in accordance with one embodiment of invention;

Figure 2 is a view in end elevation of the machine shown in Figure 1;

Figure 3 is a fragmentary view in side elevationof the device shown in Figure 1,, showing the right side of the device as viewed in Figure 1;

Figure 4 is a fragmentary view in side elevation of the device shown in Figure 1 showing the left side;

Figure 5 is a sectional view taken along the line 5-5 of Figure 4, showing the radius form block in partly rotated position with respect to Figure. 1;.

Figure 6 is a sectional view taken along the line 6+6 of Figure 1;

Figure 7 is a fragmentary top plan view with/the removable forming parts omitted, showing, in dotted lines,

the internal gearing; Figure 8 is a fragmentary sectional view taken tilt ng the line 8-.S of Figure 5,, and showing a section of tub- ,ing in the forming grooves of the radius form block form shoe;

Figure 9 is a view in perspective of the tube clamp of the illustrative embodiment;

Figure 10 is a bottom plan view of the form shoe; Figure 1.1 is a top plan view of the rack plate; Figure 12. is a view in perspective showing the bottom and side of the embodiment of form shoe shown in Fig,-

ures 1-8;

Figure 13 is a view in perspective showing the top and side of a form shoe for use with small diameter tubes;

Figure 14 is a view in perspective showing a radiusform block complementary to the form shoe shown in Figure 13, mounted on a spindle constructed in accordance with one embodiment of this invention;

Figure 15 is a sectional view taken along the line 15-,-15 of Figure 2;

Figure 16 is a sectional view taken along the line of Figure 15; and V Figure 17 is a sectional view taken along the line 17- 17 of Figure 15.

Referring now to the drawing for illustrative embodiments of this invention, reference numeral 1 indicates a complete tube bending machine. The tube bending machine 1 is made up of a housing, on which certain fixed parts are mounted; forming members, includi g a rotating form block and a rectilinearly moving forrn shoe; a clamp, by which the tube to be bent is clamped to the form block, .and drive mechanism, mainly within the housing, by which the form block is rotated. These various elements will be described in that order.

A housing 2 consists of a base shell 3 and a top shell 4,'connected by studs 5. On the bottom of the base .shell 3 is a lug 6 by which the machine can be held .vertical leg 12 is also mounted on the top shell 4,

means of screws 14. The vise has a sliding jaw 16, moved back and forth along the leg 11 by a screw 18 which extends through a threaded hole in the leg 12. The jaw 16 has a brass or other bearing metal face plate 20, and an outwardly projecting foot 22. The horizontal vise leg 11 is T-shaped in cross section, and the jaw 16 is provided with a pair of inturned flanges which engage beneath the head of the T-shape and thus permit the jaw 16 to ride lengthwise along the leg 11 but prevent any upward or sideways displacement of the jaw 16. is cylindrical post 24 projects from the free end of the eg 12. t

A bearing bracket 90 is rotatably mounted at one of its ends on the post 24, from which it is prevented from sliding axially by a retaining ring 26. The bearing bracket 90 carries at its free end a sleeve bearing or bushing 91. A thumb screw 92 can be tightened against the post 24 to prevent the bracket 90 from sliding axially along the post.

In the drawings, two different embodiments of forming members, radius form blocks and form shoes, are shown. Referring to the embodiment shown in Figures 1-12, and 17, a radius form block 80, with which a pinion gear segment 81 is integral, has flat, parallel, top and bottom surfaces connected by a peripheral face which is perpendicular to the surfaces. A hole extends through the radius form block 80, with its axis perpendicular to the top and bottom surfaces.

' As shown particularly in Figures 1 and 5, the face of the radius form block 80 has a circular section, centered on the axially extending hole, and extending through slightly more than 180.

7 The pinion gear segment 81 is concentric with the circular section. Another section of the face of the radius form block is tangent to the circular section at a zero point, as shown in Figure l. Therebeyond, the circumferential displacement of the circular section is indicated by graduations on the top surface, as shown in Figure l. A pair of axially extending ears 130 (see Figure 4) project above and below the top and bottom surfaces respectively at the outer end of this tangential face section. On the other end of the circular section, is another tangential face section which, however, being more than 180 from the face section from which the ears 130 project, is not parallel with the latter. A flat surface 132 connects the two tangential faces.

A forming groove 82 extends around the entire periphcry of the form block 80 except for the surface 132. The forming groove 82 embraces a few degrees less than 180 and, in crosssection, is on a radius slightly less than one-half the minimum allowable outside diameter of a standard size tube to be bent, as shown in Figure 8.

A form shoe 105, for use with the radius form block 80, is rectangular, with flat, parallel top and bottom surfaces. The bottom surface of the form shoe 105 is provided with mortises 104, as shown in Figure 12, where the form shoe 105 is inverted. The mortises 104 are proportioned and arranged to receive tenons 102 on a rack plate 100. The rack plate 100 has teeth 101 along one long edge, adapted to mesh with the teeth of the pinion gear segment 81. One of the flat sides of the form shoe 105 is provided with a groove 106 which, like the groove 82 of the radius form block 80, embraces a few degrees less than 180 and, in cross section, is on a radius slightly less than one-half the minimum allowable outside diameter of a standard size tube to be bent, as shown in Figure 8. On the opposite face of the form shoe is another forming groove 107, for use with a different diameter of tube and different radius form block.

The embodiment of radius form block and form shoe shown in Figures 13 and 14 is particularly adapted to use with thin-walled tubing of small diameter, for example from one-eighth inch to five-sixteenth inch, outside diameter, although it can be used with other sizes. It is adapted to maintain the alignment of the forming grooves so that no relative axial shearing movement between the form block and form shoe is permitted. In this embodiment, a radius form block 70 has flat, parallel, top and bottom surfaces, connected by a face which is perpendicular to them, and a hole extending perpendicularly between them. The face of the radius form block 70 has a circular section centered on the axis of the hole and extending through slightly more than 180". As was the case with the first embodiment of form block described, one section of the face of the form block 70 is tangent to the circular section at a zero point. A pair of axially extending ears project above and below the top and bottom surface respectively at the outer end of this tangential face section, as shown in Figure 14. On the other-end of the circular face section, is another tangential face section which, however, being more than from the face section from which the ears 130 project, is not parallelwith the latter. A flat surface 132 connects the two tangential faces.

A forming groove 72 in the face of the form block 70 extends around the entire periphery of the form block, except along the flat surface 132'. In this embodiment, on either side of the groove 72, the face is provided with ribs 73 lying parallel with and extending coextensively with the groove 72.

A rectangular .form shoe 205 is provided along one of its flat side faces with a forming groove 202 corresponding with the groove 72 in the form block 70. On either side of the groove 202, the form shoe face is provided with grooves 203 complementary with the ribs 73. In the embodiment of form shoe shown in Figure 13, a groove 207 is provided along the side face of the form shoe opposite the side face along which the

grooves

202 and 203 extend. As is the case with the form shoe 105, the form shoe 205 is provided in its bottom surface with mortises adapted to receive tenons on a rack plate, and can be used for two different sizes of tubing merely by turning it around, because the lands adjacent the

grooves

202 and 203, like the lands adja cent the

grooves

106, 107 and 207, are fiat, and provide a sturdy and accurate bearing surface against the face plate 20. The forming grooves in the radius form block and form shoe of this embodiment, like those of the embodiment shown in Figures l-5, are of smaller radius than the tubes to be bent.

Examples of radii of grooves in the form block and form shoe of the embodiment shown in Figures l-l2, for use with standard sizes of thin-walled stainless steel tubing are:

CD. of Tubing Radius of Grooves (istandard (i.00l') manufacturing tolerances) Inches I nchea as s 247 $4 .308 as 370 4 Examples of radii of grooves in the embodiment of form block and form shoe shown in Figures 13 and 14, for use with standard sizes of thin-walled, small diameter stainless steel tubing, are:

CD. of Tubing Radius of Grooves (istandard (=t=.001") manufacturing tolerances) Inches Inches .060 as .091 ids 122 A 153 fie The axially extending ears 130 on each of the embodiments of radius form block serve to retain a clamp 140. The clamp 140 is constructed in the form of a yoke with legs 141 and a connecting bridge 142. The inside surface of the legs 141 is cut away to form oppositely disposed laterally extending channels 147 and to define an inturned lug 143 at the end of each leg. A clamping block 146 is wider than the legs 141 and taller than the distance between the inside surfaces of the legs 1141 but shorter than the distance between the bottoms of the channels 147 in the legs 141, so that the clamping block may be slipped between the channels 147. The top and bottom faces of the clamping block 146 are cut away to form channels within which the legs 141 between the channels 147 and the bridge 142 are received, as shown in Figure 9. Opposite faces of the clamping block 146 are provided with laterally extending grooves corresponding with the forming grooves of the form shoe with which they are to be used. An adjusting screw 144 extends through a tapped hole in the bridge 142. The end of the adjusting screw 144 which extends between the legs 141 carries a plate 145 which fits closely but slideably between the legs 141 and bears against the clamp block 146. The other end of the adjusting screw 144 is adapted to take a wrench.

The radius form block 80, the embodiment shown in Figures 1-8, 12 and 17, is keyed to a form block carrying section 64 of a spindle 60. The section 64 extends through the hole in the form block 80. Beyond the upper surface of the form block 80 the diameter of the spindle 60 is reduced to provide an upper bearing section 65 with a shoulder between it and the form block carrying section 64. The form block 80 rests on an annular shoulder formed by the enlargement of the diameter of the spindle 60. A further enlarged diameter of the spindle 60 defines an intermediate bearing section 63. Below the intermediate bearing section 63, the spindle 60 is grooved axially to provide splines 62. The lowermost part of the spindle 60 is reduced in diameter to provide an annular bearing shoulder 66 and a lower bearing section 61.

The embodiment of radius form block 70 and a pinion gear segment 71, shown in Figure 14 are keyed to a spindle 60, similar to the spindle 60 upon which the form block 80 is mounted.

As shown particularly in Figure 17, the spindle 60 is journaled within the housing 2, with the lower bearing section 61 of the spindle in a ball bearing 51, and the intermediate bearing section 63 journaled in a needle bearing 52. Above the radius form block, the upper bearing section 65 is journaled in the sleeve bearing 91 of the bearing bracket 90. As shown in Figures 4 and 6, the post 24 upon which the bearing bracket 90 is mounted, is sufficiently tall to permit the bearing 91 to be lifted above and swung clear of the upper bearing section 65.

Inside the housing, between the ball bearing 51 and the needle bearing 52, the splines 62 of the spindle 60 mesh with complementary internal splines 54 of a bull wheel 50. The bull wheel 50 is drh'en by a worm gear 43, as shown particularly in Figure 15. The worm gear 43 is keyed to a shaft 41. The shaft 41 is journaled at its end adjacent the worm gear 43 in a sleeve bearing mounted in a suitable boss in the housing 2, as shown in Figure 15, and at itsv other end, in a ball bearing 42. The shaft 41 projects beyond the bearing 42 and outside of the housing 2, where it is provided with a squared end 45 upon which a wrench may be put. Between the bearing 42 and the worm gear 43, a helical gear 40 is keyed to the shaft 41.

A helical drive gear 30, the teeth of which mesh with the helical gear 40, is mounted on a shaft 31, the axis of which is at right angles to the axis of the shaft 41. The lower end of the shaft 31 is journaled in a ball bearing 34 mounted in a suitable boss .in the base shell .31 projects through and beyond a boss in the top shell 4. The projecting shaft 31 is provided with a squared end 35 so that a wrench can be put on it. The number of teeth on the drive gear 30 may diflier from the number on the helical gear 40, so that greater or less rotational speed can be imparted to the shaft 41 by turning the shaft 31 than by turning the shaft 41 directly.

A ratchet-type box wrench 15, as shown in Figure 1, can be used on either the shank 35, to turn the shaft 31, or on the shank 45, to turn the shaft 41 directly.

In the operation of the tube bending machine of this invention, with the embodiment of radius form'block and form shoe shown in Figures 1-12, assuming that the machine is assembled as shown in Figures l-6, that a length of tubing is in place, with one end of the tubing clamped to the radius form block by means of the clamp 146, as indicated in Figure 5, and that the various parts are in the position shown in Figure 1, it is only necessary to put the wrench 15 on the squared end 35 of the shaft 31 in such a Way that the wrench acts in a clockwise direction as viewed in Figure 1, and to turn the shaft 31. The turning of the shaft 31 rotates the gear 40 and the shaft 41, rotating the worm gear 43 and the bull wheel 50. The turning of the bull. wheel 50 rotates the spindle 60, hence the form block 80 in a clockwise direction as viewed in Figure 1. The form block is shown as having been rotated through an arc of something less than in Figure 5. As is most clearly shown in Figure 6, the form block 80 and the rack plate are aligned horizontally, with the teeth of the pinion gear segment 01 meshed with the teeth 101 of the rack plate. The rack plate rests upon and slides along the foot 22 of the jaw 16. The rack plate is thus moved rectilinearly along the bearing plate 20 by the pinion gear segment 81, as the radius form block 80 is rotated. As shown in Figure 8, the tubing being bent serves to hold the form shoe and radius form block in alignment. This is entirely satisfactory in the larger sizes of tubing for which the radius form block 80 and the corresponding form shoe 105 are used. As the radius form block is turned, the tubing is pulled into the groove 82 which, as has been explained, is of slightly less radius than the tubing. This tends to compress the tubing along a vertical diameter as viewed in Figure 8, which overcomes the tendency of the tubing to collapse along the horizontal diameter as viewed in Figure 8. The net result of the bend produced by the device of this invention, is to reduce the diameter of the tubing slightly, but to produce a substantially round section throughout the bend.

In order to remove the bent tubing from the machine, the clamp screw 144 is backed off to release the end of the tube and permit the clamp to be slipped off the ears 130. The vise screw 18 is backed off a short distance to relieve the pressure of the form shoe 105 on the tubing. The tubing is then either simply slipped out between the form shoe and the form block or, if the tubing is long or has other bends in it or is being bent in place after it is installed, the thumb screw 92 of the bearing bracket 90 is loosened, the bearing bracket 90 is lifted until the bearing 91 is clear of the upper bearing section 65 of the spindle and is swung to one side and the screw 18 is backed off until the tubing can be removed from between the form shoe and the form block.

If, now, it is desired to bend a length of tubing of a larger diameter, corresponding with the forming groove 107 of the form shoe 105, the form shoe 105 is simply lifted from the rack plate 100, turned around, and seated again on the rack plate, with the tenons 102 taking into the mortises 104. The radius form block 80 is slipped axially from the spindle 60, and another radius form block, with a forming groove corresponding to the forming groove 107, is slipped into place. The bearing bracket 90 is swung into place and the thumb screw 92 is tightened.

'sponding to the groove 107 in operative position.

The radius form block is turned to the zero position as shown in Figure 1 by turning the shaft 31 counterclock wise. Alternatively, before the bracket 90 is in place the spindle 60 can be lifted from the housing 2, turned until the form block is properly directed, and replaced. If the splines do not mesh in exactly the proper position, the shaft 31 can be turned in either direction to properly orient the form block. The tubing is positioned between the form block and form shoe, either by inserting the end of the tubing between them or by swinging the bearing bracket 90 to one side, and in effect assembling the form block and form shoe around the tubing. The clamp block 146 is removed from the clamp, turned around, and reinserted between the legs 141, with the groove corre- The lugs 143 are slipped behind the ears 130, with the end of the tubing between the groove in the radius form block and the groove in the clamp block 146, and the screw 144 is tightened until the end of the tubing is securely clamped.

With large diameter tubing, it is frequently desirable to place the machine in a vise, with the lug 6 gripped between the jaws of the vise. In the event that the gear ratio between the gear 40 and the gear 30 is less than 1 to 1, it will probably be desirable to put the wrench 15 on the squared end 45 of the shaft 41 and turn the shaft 41 directly, in a clockwise direction. as viewed in Figure 3, to exert the greatest amount of force on the radius form block.

Within limits, the gear segments carried by different radius blocks can be uniform, so that the same rack plate can be used with form shoes carrying forming grooves of various sizes. However, it may be necessary or desirable to use different rack plates with difierent sizes of tubing or it may be desirable to use different rack plates with the same sizes of tubing made from difierent materials. For example, if it is desired to produce either a small overtravel or undertravel of the form shoe with respect to the form block, gear segments of difierent radii and rack plates of diiferent widths can be used with form blocks and form shoes having forming grooves of the same radii.

If, now, it is desired to bend a tube of small diameter, the radius form block and the spindle 60 are removed, and the spindle carrying the form block 70 is slipped into place. The radius form block 70 is brought to its zero position by turning either the shaft 31 or the shaft 41 in the appropriate direction. As can be seen by comparing the pinion gear segment 71 as shown in Figure 14 with the pinion gear segment 81 as shown in Figures 3 and 5, a different rack plate, with teeth corresponding to the teeth of the gear segment 71, will have to be used. The appropriate rack plate is simply laid on the foot 22 and the form shoe 205 is seated on the rack plate, with the tenons of the rack plate taking into the mortises in the form shoe. A tube to be bent is inserted between the form shoe 205 and the form block 70, the clamp 140 is put into place, with a suitable clamping block with grooves complementary to the ribs 73 and a groove corresponding with the groove 72, and the clamping block is clamped tightly against the end of the tube. The screw 18 is turned down until the jaw 16 has moved the form shoe 205 into snug engagement with the tube to be bent, the tube lying within the

grooves

72 and 202. In this posture, the ribs 73 will extend within the grooves 203. When the radius form block 70 is turned, the engagement of the ribs 73 with the walls of the grooves 203 ensures against any disalignment between the form shoe 295 and the form block 70. This is especially important with thin walled tubing of small diameter which might otherwise be flattened between the form shoe and form block or subjected to shearing forces if the form shoe and form block should move axially relative to one another. As can be seen from Figures 3, 6 and 8, a small gap is left between the form shoe and the form block by virtue of the fact that the forming grooves are of smaller radius than the tubing to be bent, and this situation aggravates the problem of maintaining alignment when tubing of small diameter is being bent.

Numerous variations in the construction of the tube bending machine of this invention, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure.

Preferably the gearing of the drive gear 30 is such that one revolution of the shaft 31 will turn the shaft 41 through more than one revolution, for example one and a half revolutions. This is particularly advantageous in bending small diameter tubing, when the machine need not even be put into a vise. As has been pointed out in connection with the operation of the machine, a length of tubing can be bent in the middle as well as at one end, and can be bent in place, since the clamp 140 and the form shoe can be put in place around a tube to be bent, anywhere along its length. The swinging bearing bracket permits of this arrangement, and at the same time furnishes support to the spindle against the side thrust exerted by the tubing against the radius form block.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a tube bending machine in which the tube to be bent is clamped between a rotatable radius form block and a cooperating form shoe arranged for rectilinear movement in a direction substantially tangential with respect to the radius block, said form block and form shoe each having opposed faces with a forming groove for embracing respectively the diametrically opposite sides of a tube being bent, said radius form block being mounted to permit axial displacement thereof with respect to said form shoe, the improvement comprising, a rib in one of said opposed faces and a complementary shaped rib receiving groove formed in the other of said opposed faces both spaced an equal distance from the forming groove in the form block and in the form shoe and located on said opposed faces spaced from the edge of said form block and said form shoe, said rib and said complementary shaped rib receiving groove being engaged during tube bending process to prevent disalignment of the forming groove in said form block and the forming groove in said form shoe 2. In a tube bending machine having a rotatable radius form block and a rectilinearly moving form shoe having opposed faces on each provided with a forming groove, the improvement comprising a rotary mounting for the radius form block constructed and arranged to permit axial movement of said radius form block with respect to said mounting, a rib on one of said opposed faces and a complementary shaped rib receiving groove formed in the other of said opposed faces both spaced an equal distance from said forming groove in said form block and in said form shoe and located on said opposed faces spaced from the edge of said form block and said form shoe, said rib and said complementary shaped rib receiving groove being engaged during the tube bending process to prevent disalignment of the forming groove in said form block and the forming groove in said form shoe.

3. In a tube bending machine of the character in which the tube to be bent is clamped between a rotatable radius form block and a cooperating form shoe arranged for rectilinear movement in a direction substantially tangential with respect to the radius form block, said form block having a groove for embracing one side of a tube being beat, the improvement which comprises means defining a pair of tube-embracing grooves one each on opposite sides of said form shoe and a supporting face on a third side thereof, a plate having gear teeth along one edge, a face on said plate adjacent said edge, symmetrical cooperating male and female selectively engageable means on the faceof said plate and on the supporting face on said third side of said form shoe whereby said form shoe may be reversed end for end and detachably located on said plate with either of said tube embracing grooves adjacent the radius form block groove, said radius form block being removable and replaceable and provided with a gear segment having gear teeth meshing with the gear teeth on the said plate, whereby, when the said form block 5 is rotated, the plate and the form shoe are driven by the said gear segment.

References Cited in the file of this patent UNITED STATES PATENTS 986,654 Tattu Mar. 14, 1911 10 Oddie Nov. 9, 1926 Abramson Nov. 21, 1933 Parker Dec. 22, 1942 Lampe Aug. 13, 1946 Tirone Oct. 5, 1954 Franck Feb. 15, 1955 FOREIGN PATENTS France Oct. 1, 1920 Great Britain Dec. 3, 1928