US3370451A - Apparatus and method for pointing tubes - Google Patents

Description

Feb. 27, 1968 Filed June 28, 1965 4 Sheets-Sheet 1 INVENTOR.

JAMES W. SCHUETZ BY ATTORNEYS 19678 J. w. SCHUETZ 3,37

Filed June 28, 1965 4 Sheets-Sheet 2 Z .3. F2 4. j V INVENTOR.

' JAMESW.SCHUETZ BY Mk: /W

ATTORNEYS.

Feb. 27, 1968 J. w. SCHUETZ APPARATUS AND METHOD FOR POINTING TUBES 4 Sheets-Sheet :5

Filed June 28, 1965 INVENTOR. JAMES W. SCHUETZ BY 6 fi/W a 4M ATTORNEY$ J. w. SCHUETZ 3,370,451

APPARATUS AND METHOD FOR POINTING TUBES Feb; 27, 1968 Filed June 28, 1965 4 Sheets-Sheet 4 \k. mw M W 1 INVENTOR.

JAMES w. SCHUETZ ,SM, Wm V ATTORNEYS.

United States Patent 3,370,451 APPARATUS AND METHOD FDR PGINTING TUBES James W. Sehuetz, Pittsburgh, Pa., assignor to Slaw-Knox Company, Pittsburgh, Pa, a corporation of Delaware Filed lune 28, 1965, Ser. No. 467,235 8 Claims. (Cl. 72-402) ABSTRACT OF THE DISCLOSURE Apparatus for pointing metal tubes preparatory to drawing them through a die embodying jaw members angularly spaced apart about a central aXis and adapted to fold the walls of a tube inwardly to produce a tube having an end of reduced diameter made up of longitudinally extending ribs separated by intervening fiutes. The jaws are V-shaped and have sharp, longitudinally spaced projections that first come into engagement with the wall of the tube and hold the tube properly centered during the point.- in g operation which takes place in one continuous inward stroke of the jaws.

This invention relates to an apparatus and method for pointing tubes so drawing the tubes to reduce their diameter.

It is necessary to provide what is known as a point on the end of a tube before it can be drawn through a die to reduce its diameter; the point must have an overall transverse dimension such that it readily can be inserted through the die and must be long enough so that the projecting end of the point can be grasped by gripper tongs or jaws or the like on the other side of the die. If the drawing operation is to be carried out satisfactorily, the point and the juncture between the point and the remainder 3 of the tube must be nearly as strong as the tube itself so that the metal will not be pulled apart during the drawing operation, and the point should be accurately centered with respect to the tube to prevent distortion of the tube during drawing. Also, the pointing operation should be accomplished quickly and without requiring skill on the part of the operator and the apparatus for carrying out the pointing operation should be sturdy, simple and capable of being manufactured at reasonable cost.

A general object of the present invention is to provide a machine and method for pointing tubes that meets the foregoing requirements. Other objects and advantages of the invention will become apparent from the following description of a preferred form thereof, reference being made to the accompanying drawings in which:

FIGURE 1 is a vertical axial section illustrating a preferred form of apparatus embodying the present invention.

FIGURE 2 is a transverse section taken along line 2-2 of FIGURE 1.

FIGURES 3 and 4 are side elevation and end views, respectively, of a typical tube that has been pointed in the illustrated apparatus.

FIGURES 5 and 6 are side and end elevations, respectively, of one of the gripper jaws used to deform the tube.

FIGURE 7 illustrates the inner or working face of the gripper jaw illustrated in FIGURES 5 and 6.

FIGURE 8 is a fragmentary elevation showing the initial engagement between the gripper jaws and a tube to be pointed.

FIGURE 9 is a section taken as indicated by line 9-9 of FIGURE 8.

FIGURE 10 is a similar section, but showing the jaws in their innermost position.

FIGURE 11 is similar to FIGURE 10, but shows a smaller tube, the tube being of the size shown in FIG- URES 3 and 4.

that they may be inserted into dies for 3,373,451 Patented Feb. 27, 1968 Briefly, a preferred form of apparatus comprises a fluid operated chuck or similar mechanism that is adapted to urge a series of V-shaped gripper jaws or dies radially inwardly into engagement with the length of tube to be pointed. The jaws each have a series of longitudinally spaced points that first engage the tube and thus hold the tube against slippage with respect to the dies. As the jaws move inwardly, they fold the tube into a fluted form having a maximum dimension sufficiently smaller than the original outer diameter of the tube to permit the end of the tube readily to be inserted into the drawing die. The folding operation is completed in one continuous movement of the jaws and as soon as the inward movement of the jaws is completed, they are automatically retracted so that the tube can be removed from the apparatus ready for drawing through a die.

As shown in FIGURES l and 2 of the drawings, a preferred form of apparatus comprises a cylinder 10 supported on an appropriate base made up of a horizontal plate 11 and vertical plates 12 disposed at either end of the cylinder 10 and having arcuate saddle portions to receive the cylinder. The vertical members 12 preferably are welded to the base member 11 and the cylinder 10 may be welded to the vertical members 12. The internal bore of the cylinder 10 has a rear portion 14 of greatest diameter, an intermediate portion 15 of reduced diameter and a forward end portion 16 of enlarged diameter as compared to the intermediate portion 15. At the front end of the cylinder there is a front cylinder head 18 that is held in place by a key 19 and an annular ring 20 and is prevented from inward movement by a shoulder 21 in the cylinder bore. There is also a rear cylinder head 22 that is held in place against a shoulder 23 in the cylinder bore by a key 24 and a ring 25. The rear cylinder head is sealed to the cylinder as by a conventional O-ring 26.

In order to form the required points on tubes, at plurality of angularly spaced gripper jaws are disposed within the cylinder. Six jaws are shown in the drawings, but fewer or more jaws can be employed if desired. A tube T is shown in FIGURES l and 2 to illustrate the initial engagement between the jaws and the tubes. In order to move the jaws 3!) inwardly to deform the tube to provide the desired flutes and reduce the diameter thereof, a hydraulically operated chuck 31 is disposed within the cylinder 10. Chuck 31 is provided with radial slots 32 in which the jaws 30 are slidably mounted and in order to move the jaws inwardly and outwardly upon axial movement of the chuck, the slots 32 are T-shaped as shown, with enlarged head openings 33 that are defined by sloping outer camming surfaces 34 and inner camming surfaces 35 that are parallel to the surfaces 34. The jaws 30 are provided with T heads 36, preferably composed of a material such as bronze in order to reduce friction the strips being secured to the jaws by cap screws 37. The forward ends of the jaws are provided with wear plate 38 that bear against the inner surface of the forwarr cylinder head 18 while the rear ends of the jaws bea against a washer 40 that is supported by a plug 41 the projects inwardly from the rear cylinder head 22. Th jaws are prevented from longitudinal movement by th front cylinder head 18 and the washer 40 and thus recir rocating movement of the chuck 31 within the cylind: 10 will cause the dies to move radially inwardly and on wardly. The jaws and the chuck are shown in full lint in FIGURE 1 in their fully retracted position; the broke lines in the lower part of FIGURE 1 indicate the inne most position of the jaws and the corresponding forwa' position of the chuc In order to reciprocate the chuck 31 Within the cylind It), the chuck is provided with a rear piston portion I that operates within the bore 14 and also slides alo the plug 41, the piston portion 45 being sealed to t cylindrical surface 14 and the outer surface of plug 41 is formed by folding the wall of the tube inwardly upon y appropriate packlngs such as the O-rings 46 and 47, itself to provide flutes 71 It Wlll be noted that the ribs respectively The chuck rs also provided with a forward 72, which define the flutes or recesses, extend substantlally plston portion 49 that fits within the intermediate bore radially and are substantially equally angularly spaced 15 of the cylinder, the required seal being provided by a and that the wall of the tube at the outer edge of each packing such as the O-ring 50. With this arrangement, rib is bent through a suiiicient angle that adjacent poradmission of fluid under pressure to the space 52 in back tions of the tube wall substantially contact each other as of the piston 45 will urge the chuck 1n the forward dlrecshown at 73 Th inward folding of the tube wall does not tion toward the front cylinder head 18 and cam the jaws substantially elongate the tube in the axial directions, and

inwardly to deform a tube disposed within the jaws. Also, therefore the cross-sectional area throughout the point is i substantially the same as the cross-sectional area of the piston 49, admission of fluid to the space, 53 between original tube and has nearly the same tensile strength. the two piston portions of the chuck will cause the chuck The point merges into the original tube as shown at 74, to move rearwardly in the cylinder and thus retract the the merging portion being formed by the outwardly flared jaws from the tube with which they have been engaged. end portions 75 of the gripper jaws 30. The bottom of Suitable fluid conduits 55 and 56 leadin to the spaces each flute has a series of deeper indentations 76 these 52 and 53, respectively, are provided. These conduits are being formed by the sharp V-shaped pro ections 77 on the connected to a source of fluid under pressure through g ipp l appropriate controls which can take any convenlent for-m aW m m rs 30 f a preferred form adapted to pr0- Preferably, the controls are arranged so that the operator 20 dllee Points Sheh as Shown in FIGURES 3 and 4 e Hillsonly has to push a button whereupon fluid under pressure halted n FIGURES 1 and 2 and On a large! scale In chuck m the forward d re tion and urgmg th aw i that are adapted to slide in the radial slots 32 of the wardly t oint th tube, Pr f bl th control i u h chuck. The outer surfaces of the body portions are slanted that fluid under pressure is applied to the space 52 until as Shown to pp the T heads 36 The inner P0111011s the ba k pressure bmld up t a predetermined d of the aws extend parallel to the common axis of the whereupon the connections are reversed to supply fluid ehrllek, the Cylinder 19 and the tube to he Pointed The under pressure to the space 53 through the conduit 56 inner Portions of 1lhe l are formed into P as and permit fluid to be discharged from the space 52 to Shown at With the VS Pointing radially ihWaidiY t e sump. This operation continues until a predetermined Ward the Common axis and their aPeXeS Paiaiiei t0 the back pressure is built up in the conduits leading to the 00111111011 aXiS- The ihehlded ahgie 0f the V8 is Preferably space 53, whereupon the pressure is shut OE and h equal to the angular spacing between the radial slots 32 apparatus is then in condition for another operation. in the Chuck and heiWeen the l 30 When y are in Controls capable of performing this type of sequence of 35 Position Within the ehuek- Thus, ih'ihe eXamPie g operations are well known to those skilled in the art and the ail'glliar Spacing between the l members is 60 are not described herein, 7 degrees and the included angle of the V-shaped portion In order to limit the retracting stroke of the chuck and of each of the l members is Preferahiy also 60 degreesthu to limit the outward movement of the jaws to a posiwith this arrangement, eeeh Side 81 Of a P POIiIOH tion in which their inner edges define a circle having lies Parallel to a Side 31 an adjacent j memberh approximately the external diameter of the tube to be j members When moved inwardly y the chuck fold pointed, an ad ustable stop is provided on the rear end the Wall Of the e o he fo m shown each nb 72 f h h k 31 T comprises a guide bar 9 that 18 being made up of two thicknesses of tube Wall folded p e ed into an opening in the rear of the piston port on substantially into contact with each other as shown at 73 In order to provide clearance for the walls of light formed in an ad ustment shaft 62 that is threaded as at gauge andrrelatlvely small dlameter tubes, the P 64 m a hollow boss 63 secured to the rear cylinder head Pomts 80 of the j s are relieved adjacent the r of 22 h Inner end of h adjustment h ft 2 has a flange. the Vs as shown at 82. The relieved portions make it For example with the shaft in the boss can be readily ad usted. The shaft is this arrangement a slhgie machlhe can form Points on l d agamst 1 k Where passes h h h h tubes with a range of outside diameters from 1 750 inch to der head 22 by an O-rrng 69 With this arrangement rear- 0-625 lheh Without requiring adliisti'hehi eXeePi 0f the ward movement of the chuck is stopped by engagement retracted Position of ihejaws y the hand Wheel of the chuck with the end flange 66; the position of the As noted above, the tubes to he Peihied are first llange can be adjusted by the hand wheel 68. The position gaged y the Projections 77 0f the i These are iehgi' of maximum retraction of the jaws is shown in FIGURE illdihaiiy spaeedl along the aPaXeS 0f the V8 and are l. The guide bar prevents relative rotation between formed p y y cutting y Or relieving the Inner h h k d th li d 10 60 of the jaws as shown to provide flat surfaces 83, leaving ohm strong pointed portions of the type shown in FIG- Su fa T PTOJeCiIOHS PTefefahiY are Shghiiy eioh' RES and 4 on the ends f tubes of a Wlde mug of gated 1n the direction parallel to the axis of the tube and 123s Wlthout requmng any change In the gnpper Jaws present sharp edges 84 to a tube disposed within the M Without requiring any adjustment of the apparatus aws; As shown in the drawing, the projections 77 are ther than the adjustment of the retracted position of the aXially short as compared to e intermediate surfaces 83 1W5 b h h d wheel 3 As Shown m FIGURES 3 The manner in which the aws form the desired point nd 4, a tube T ls provided with a pointed portion on a tube IS liillsiraied H I RE 8 9 and 10 As avlng a maximum overall transverse dimension such shown In FIGURES 8 d 9 the hand wheel 68 1s emrat the point can be inserted readily into a conventional 70 P Y to adjust h p Provided y the adjustment Shaft [be and th ut di of th original b h ia tube when the tube is inserted within the chuck. Preferum transverse dimension of the point preferably is in ably, the stop is adjusted so that the points of each jaw nge of from about to about of the outer member engage the outer surface of the tube with sufliw ameter of the tube. The reduced diameter of the point 75 cient firmness that the tube is accurately centered within the chuck. The tube is inserted into the chuck until the end of the tube engages the washer 40. Then, as previously described, the chuck is actuated to move the jaw members radially inwardly.

Inasmuch as the first engagement between the jaw members and the tube is with the points 77, the sharp edges 84 of the points first indent the tube and thus prevent slippage of the tube with respect to the jaw members. Continned inward movement of the jaw members then simply folds adjacent portions of the tube wall toward each other until, as shown in FIGURE 10, these wall portions are substantially in engagement with each other. When this position is reached, no further inward movement of the jaw members can take place by merely bending the metal; the metal would have to be compressed to permit the surfaces 81 of adjacent jaw members to come closer together and to permit the jaw members to move nearer to the center line of the chuck. The pressure in the cylinder in back of the piston portion 45 of the chuck therefore increases and, as previously described, the chuck is returned to its initial position with the rear surface 67 of the chuck in engagement with the flange 156 of the adjusting shaft. This occurs when the parts have reached the position shown in FIGURE 10.

It will be noted that the sharp points 77 of the jaws somewhat penetrate the bottoms of the flutes thereby producing the indentations indicated at 76 in FIGURE 3. Also, the outwardly flared portions 75 of the jaws produce the merging areas 74 between the point and the body of the tube. The bottoms of the fluted portions between the indentations 76 are rather flat as shown at 86, having been formed by the flat intermediate areas 83 of the jaws. The point is accurately centered with respect to the tube and accurately formed because the initial adjustment of the retracted position of the jaws insures that the tube will be properly centered with respect to the jaws when the operation is commenced and because the sharp points on the jaws substantially eliminate the possibility of slippage between the metal of the tube wall and the jaws. The chuck moves the jaws inwardly uniformly and thus provides the required accurate point in a single operation. After the jaws have been automatically retracted by the chuck, the operator only has to remove the pointed tube from the chuck and insert it through the drawing die in the usual manner.

FIGURE 11 illustrates the conclusion of a pointing operation as applied to a tube of smaller diameter and thinner wall. In carrying out this operation, the hand wheel is operated to screw the adjusting shaft inwardly and thus limit retracting movement of the jaws to the smaller outer diameter of the tube. The folding operation occurs as before. However, it will be noted that the ribs 87 of this smaller lighter gauge tube are disposed within the relieved portions 82 of the jaws. If the jaws were not relieved, it would not be possible to point tubes of such small diameter using the same machine and the same jaws that are capable of pointing tubes of larger diameter and heavier wall. As noted above, a present type of machine is capable of pointing tubes having a Wide range of outside diameters and of wall thicknesses. With tubes of thinner wall thickness, the points 77 frequently penetrate through the tube wall at the face of the indentations 76. This insures accurate holding of the tubes and centering of the tubes with respect to the chuck and the jaws and any weakening of the point that this action creates is inconsequential.

From the foregoing, it will be evident that the invention provides a method and apparatus whereby tubes of a wide range of sizes and wall thicknesses can be rapidly and accurately pointed by a single operation in a simple, sturdy and relatively inexpensive machine. The points are accurately centered with respect to the tube, the reduction in dimension is adequate for ordinary drawing operations and the strength of the points and the connection between the points and the tube is adequately maintained so that the tension exerted on the points during the drawing operation can be sustained without breakage.

The essential characteristics of the invention are set forth in the appended claims.

I claim:

1. Apparatus for pointing metal tubes preparatory to drawing them through a die, comprising a plurality of jaw member angularly spaced about a central axis; means for moving all of the jaw members simultaneously and at the same speed in radial directions toward said axis and for retracting said jaw members away from said axis to a definite position at which the jaw members are substantially radially equidistant from said axis, each of said jaw members having an inner V-shaped portion provided by plane surfaces extending parallel to said axis and adapted to engage the wall of a tube to be pointed, the V-shaped portions pointing radially inwardly toward said axis, the apexes of the V-shaped portions of said members each having a plurality of longitudinally spaced, sharp, tube-engaging projections and the jaw members having tube-wall engaging surfaces between the projections, the projections being axially short as compared to the length of the surfaces between the projections.

2. Apparatus according to claim 1 wherein the projections have sharp, tube-engaging edges formed by the intersection of the plane surfaces of the jaw members.

3. Apparatus according to claim 2 wherein the surface of the V-shaped jaw members is relieved adjacent the apexes of the VS to provide clearance for the material of the wall of a tube being pointed.

4. Apparatus according to claim 1 wherein the jaw members are substantially equiangularly spaced about the axis and the included angle of each V-shaped portion is substantially equal to the angular spacing between adjacent jaw members.

5. Apparatus according to claim 1 wherein the means for moving the jaw members comprises a cylinder coaxial with said axis, a chuck mounted in said cylinder, said jaw members being radially slidable in said chuck and said chuck and said jaw members being provided with cooperating camming surfaces whereby longitudinal movement of said chuck within said cylinder in a forward direction moves said jaw members radially inwardly and toward said axis and movement of said chuck in a rearward direction causes said jaws to retract outwardly, and hydraulic means for moving said chuck longitudinally with respect to said cylinder.

6. Apparatus according to claim 5 wherein an adjustable stop is provided to limit the rearward movement of said chuck thereby limiting the retracting movement of said jaws.

7. Apparatus for pointing tubes comprising a cylinder having an open end, a chuck mounted in said cylinder and coaxial therewith, hydraulic means for moving said chuck axially with respect to said cylinder; a plurality of jaw members substantially equiangularly spaced about the axis of said cylinder, said jaw members being radially slidable in said chuck and being restrained against axial movement within said cylinder, said jaw members and said chuck being provided with cooperating camming surfaces whereby axial movement of said chuck within said cylinder in a forward direction moves said jaw members radially inwardly toward said axis and movement of said chuck in a rearward direction causes said jaws to retract outwardly from said axis; an adjustable stop disposed at the end of said cylinder opposite said open end to limit the rearward movement of said chuck thereby limiting the retracting movement of said jaw members, each of said jaw members having an inner V- shaped portion adapted to engage the wall of a tube to be pointed, the V-shaped portions pointing radially inwardly toward said axis and being formed by plane surfaces extending parallel to said axis and each of said members having a series of axially spaced, sharp, tube-engaging projections formed by the intersection of said planes, the

jaw members being relieved between said projections to provide substantially flat tube wall engaging surfaces between the projections.

8. The method of cold-forming points on metal tubes which includes the steps of disposing a plurality of jaw members about an axis with the members substantially equiangularly spaced about the axis, the jaw members pointed into the space between said jaw members with said projections engaging the outer surface of the tube and locating the tube concentric with said axis, then mov ing the jaw members inwardly toward said axis simultaneously and at the same rate of speed, the projections of said jaw members initially forming indentations in 8 said tube and retaining said tube substantially concentric with said axis, and continuing the inward movement of said V-shaped members without interruption to fold adjacent portions of'the tube wall toward each other until the wall portions are substantially in engagement with each other without substantially reducing the wall and a provide radially extending ribs defining intermediate flutes, and thereafter retracting said jaw members and releasing said tube therefrom.

References Cited UNITED STATES PATENTS 2,211,622 8/ 1940 Hunziker 7-2402 2,997,911 8/ 1961 Woolley 72402 2,999,405 9/ 1961 Ewart 72-402 3,154,978 11/1964 Baker 72402 CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner.

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