US1819376A

US1819376A - Tube swaging machine and method

Info

Publication number: US1819376A
Application number: US733930A
Authority: US
Inventors: Muller Friederich
Original assignee: Individual
Current assignee: Individual
Priority date: 1924-08-25
Filing date: 1924-08-25
Publication date: 1931-08-18
Anticipated expiration: 1948-08-18

Description

Aug. 18, 1931. F. MLLER TUBE SWAGING MACHINE AND METHOD 2 Sheets-Sheet l Filed Aug. 25, 1F24 Aug. 18, 1931. F MLLER 1,819,376

TUBE swAGING MACHINE AND METHOD Filed Aug. 25, 1924 2 Sheets-Sheet 2 /MI l a .Fw f/ www Patented Aug. 18, 1931 UNITED sTATEs FRIEDERICH MULLER, 0F ELIZABETH, NEW JERSEY TUBE SWAGING MACHINE AND-METHOD Application filed August 25, 1924. Serial No. 733,930.

This invention relates to means and methods for forming tube of varying diameter by the operation of swaging.

The invention contemplates variation of the diameter by variation of the thickness of the tube wall, by varying the internal diameter of the tube, the wall thickness remaining the same, or by varying both the thickness of wall and the interior diameter of the tube.

By far the greatest amount of tube is of iron or steel although some are of brass and other materials. Swaging is well adapted for working tube for the purpose as indicated as the forging of the metal during the operation causes the metal of the tinished tube to be of good quality, and for other reasons. The shock of the swaging tool upon the tube as it is driven inwardly by the driving means is, however, liable to distort or otherwise damage the tube being worked, especially if it has a thin wall.

The main object of the present invention is to avail of the advantages of the swaging operation in connection with the treatment of tubes as indicated.

In the accompanying drawings, which illustrate the invention,

Fig. 1 is a central, vertical, longitudinal section of a swaging machine embodying the invention of apparatus and whereby the method of the invention may be carried out;

Fig. 2 'is an end elevation of the machine of Fig. l, looking from the left of that tigure;

Fig. 3 is an enlarged view of a 'portion of Fig. 1, showing more clearly the swaging head and adjacent parts; v

Fig. 4 is a section on the line 4 4 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 3 but with the driving pulley omitted; and

Fig. 6 is a fragmentary View showing the swaging members closed in from the position as shown in Fig. 3 andillustrating the tapering of the tube in consequence.

Fig. 7 lis a view the same as Fig. 6 with a modified form of mandrel nose.

Referring to the drawings, the apparatus comprises a frame 1 along which a drawhead 2 is moved by means of a feed-screw 3, the

engagement of the drawhead with the feedscrew being effected by means of av partial nut 4 which is secured to, and may be moved into and out of engagement with the feed- 5 screw by, va vertically reciprocating plunger 5 sliding in the drawhead. The plunger 5 is adapted to be reciprocated in one direction or the other by suitably turning a collar 6, which surrounds the plunger and has a cam slot 7 into which a pin 8 upon the plunger extends, this turning being effected by means of a handle 9. The drawhead also comprises a pin 10 adapted to enter within the end of the tube 11 to be swaged, this end of the tube being adapted to be clamped against the pin 10 by a suitable screw-clamp 12 so that the tube will be drawn along with the drawhead when secured thereto but may be released therefrom by releasing the clamp. 7g

`The drawhead is also provided with a stop pin 13 for limiting the approach ot' the drawhead to the swaging head.

The swaging head comprises an-outer stationary member 14 which may be formed integral with the frame as shown. Mounted in recesses in the member 14 are circular rollers 15 which are prevented from leaving the recesses by means `of a plate 16 secured to the face of the member 14. The rollers 15 project somewhat within the inner face 17 of the member 14 so as to operate the swaging members in a manner as will be herein after referred to.

Rotatably mounted in the frame 1 is a shaft 18. The shaft is rotated in any suitable manner as by a driving pulley 19 fixed thereto. Within the swaging head the shaft 18 carries a plate 20 having grooves cut in its face wherein reciprocate the swaging members. Each of the swaging members comprises an anvil portion 22 adapted to engage with the rollers 15, a reciprocating plunger 23 and al working member 24 fixed to the plunger 23 and adapted to engage with the work. The plunger 23, and therefore the whole swaging member, is secured in the slot 21 by means of the plate 25 secured to the face of the plate 20. The anvils 22 are each wedge-shaped longitudinally as shown and may be slid longitudinally to adjust the radial length of the swaging member from the anvil face 24 to the working face, the plunger and anvil being held in definite relationship to each other radially of the head, but permitting sliding therebetween, by means of a dove-tailed connection 26. Each of the wedge-shaped anvils may be moved longitudinally to adjust the swaging members, as referred to, by means of a rod 27 extending through a channel in the shaft 18, the bent up end 28 of the rod engaging in a recess 29 in the anvil member. It will be seen that the anvil members 22, although adjustable as described, are free from any engagement with other parts which would prevent their reciprocation with the swaging members under the action of the hammer rolls 15. All of the rods 27 are secured to a collar 30 sliding upon the shaft 18. The shaft 18 may conveniently be formed (see Fig. 5) by making an inner shaft 31 having recesses in which the rods 27 are laid and then placing over the whole a sleeve 32 which is secured to the shaft 31 by means of pins 33. It will be seen, particularly from Figs. 3, 4, and 6 that the Working face 24 of each swaging member is convex both transversely and longitudinally. There the Work is in the form of a cylindrical tube, the longitudinal extent of the innermost working face is not of so much importance but where a tapered tube is to be formed, the working contact with the metal should be very narrow so that the working member will be adapted to operate properly upon succeeding tube sections of different diameters without having itsoperation upon one section of one diameter interfered with by engagement with an adjacent section of different diameter. By forming the Working face to be longitudinally convex the desirable result as indicated is attained. lVith regard to the transverse curvature of the working face of a swaging member, this has usually been concave. This is a good construction where the curved surface of the work is of uniform diameter but where this surface is tapered the cavity which would fit a section of one diameter would not fit a longitudinally displaced section of another diameter. In order to adapt the working faces to produce the best results-in tapering, the transverse curvatures should be made convex and this in combination with the longitudinal convexity referred to presents a substantially globular convexity to the Work and this has been found to be best adapted for tapering. The shaft 31 has a central longitudinal hole 34 through which the mandrel 35 extends, the mandrel being adapted to slide longitudinally in the shaft. Secured to the rear end of the mandrel 35 is a grooved collar 36 whereby the mandrelrmay be shifted longitudinally. The forward end of the mandrel 35 is tapered as shown at 37 so that by shifting the mandrel longitudinally the diameter of the mandrel at the point of contact of the swaging members may be varied.

Fixed to the frame 1 is a stud 38 of H- shaped cross section upon which slide respectively the two members 39 and 40, the member 39 having an arm 41 extending into the groove 42 of the collar 30 so that this collar, and therefore the working anvils of the swaging members, may he moved longitudinally with the member 39 but without interfering with the rotation of the collar 30 and its connected parts. Secured to the member and extending into the groove 43 of the collar 36 is an arm 44 so that the mandrel may be moved back and forth with the member 40 but without interfering with the rotation of the mandrel.

The members 39 and 40 are moved longitudinally on the stud 38 by means of a cam drum 45 which is mounted to turn upon the Vshaft 46 of the feed-screw. The member 40 has a projection 47 extending into a cam groove 48 in the drum 45, this groove being of such conformation that the mandrel will be moved back and forth as the machine is operated to accomplish the desired results. Similarly the member 39 for shifting the swaging members has a projection 49 which extends into a cam groove 50 in the drum 45, this groove being of such conformation as to cause the desired shifting of the swaging members during the operation of the machine. The grooves 48 and 50 extend generally in a circumferential direction but are inclined to the axis of the drum, in one direction or other, at suitable points and to suitable degrees to effect the desired longitudinal shifting of their entering projections. Each of the slots or grooves is endless so that the projections may continuously traverse it during successive operations of the machine. The projections may be provided withv rollers as shown to facilitate their travel along the slots or grooves.

The manner of operating the drum 45 and also the feed-screw will now be referred to. A driving pulley 51 is mounted to turn upon the shaft 52 whichis rotatably mounted in the frame 1. The pulley 51, however, has

fixed in it a pin 53 which extends into a' circumferential groove in the shaft 52 so as to limit the longitudinal movement of the pulley but permitting its rotation on the shaft. The pulley 51 has formed upon it a clutch member 54 adapted to cooperate with another clutch member 55 splined upon the shaft 52 so that it may slide but may not turn thereon. This clutch memberV 55 is adapted to be movedinto and out of engagement with the member 54 by means of a lever 56 having forked ends engaging with a groove 57 in the member 55 so that the turning of the latter may not be interfered with. This lever 56 is pivoted at 58 on the frame of the machine.

A spring 59 normally tends to hold the coupling members 54 and 55 in engagement.

Fixed to the shaft 52 is a worm 60engaging with a worm wheel 61 secured to the shaft 46. The pulley 51 is driven at such speed, and the gearingis such, that the feedscrew is turned at a speed so thatthe drawhead will be moved along the frame at the desired rate.

Fixed to the shaft 52 is a spur gear 62 meshing with the spur gear 63 fixed to the shaft 64 `ournaledyin they frame and upon which is fixed the worm 65 which cooperates with a worm gear 66 which is free to turn upon the shaft k46 and is fixed to the drum 45. The dimensions, connections and design of the parts are such that the drum45 and the worm gear 66 will make approximately one revolution for each travel of the drawhead from one of its extreme positions to the other under the action of the feed-screw.

In order to automatically arrest the operation of the machine at the end of one draw or operation, a pin 67 is fixed in the side of the worin gear 66, this pin proJecting somewhat to one side of that gear. In the path of the pin 67 is a lug 68 fixed upon a bar 69 mounted in the frame. This bar is capable of sliding endwise and also may be turned on its axis to some extent to move the lug 68 into and out of the path of the pin 67. A spring tends to hold the lug in the path of the pin but it may be removed from that path by turning the bar Iagainst the tension of the spring 70 by means of the 'handle 71. As before stated the clutch members 54 and 55 are normally' held in engagement by means of the spring 59, but when the drawing operation is nearing its end, the pin 67 will come againsththe lug 68 and vforce the bar 69 endwise against the upper `end of the lever 56.` This will result in the disengagement of the clutch members 54 and 55 and the cutting off of power from the feed-screw and its connected devices. When the apparatus has been thus shut down, the clutch members may be permitted to reengage to start another drawing operation by so turning the handle'71 as to throw the lug 68 clear of the pin 67 when the lug will move backwardly past the pin and, on being released, will assume its position in the path of the pin as before referred to.

Obviously the clutch members 54 and 55 may be disengaged at will be manually forcing the bar 69 endwise against the lever 56.

In the operation of the machine, the tube to be swaged is of suitable thickness, is placed inside the shaft 18 and about the'circular mandrel. Its end is secured inthe drawhead (see Figs. 1 and 3) and therdrawhead is placed in proximity to the swaging head. The drawhead being then engaged with the feed screw, it will be drawn to the right (Fig. l) and the tube will be drawn in the same directionV under the swaging members of the swaging head. Meanwhile the cam drum 45 is turning, having been initiallyset so that the wedge-shaped anvils are in theirextreme left hand position andthe mandrel will be at its hand position (see Figs. 1 and 3), `that is approximately at the junction of the tapered and cylindrical portions of the mandrel. Also the shaft 18, with the swaging members is rotated by means of the pulley 19 so that they are struck and driven inwardly against the work by the rollers 15.

Assuming that the slot 50 for operating the anvils 22 to vary the approach of the working members toward the axis'of the tube, has a longitudinal inclination or pitch such that the working members are moved inwardly at a constant rate; then the exterior of the tube will be given a uniform taper (the drawhead moving at a constant speed) of a degree depending uponthe ratio of the inward movement of the swaging members to the longitudinal movement of the tube.

The thickness of the tube wall formedin the swaging head for any given position of the parts, is equal to the distance between the working face of the swaging tool when driven to its innermost position by thedriving rolls and the surface of the mandrel beneath it. If therefor, the pitch of the groove 48 is made such that as the swaging members are moved inwardly the mandrel is moved so that the distance between the swaging tools and mandrel as referred to, is constant, the thickness of the wall of the i'i'nished will be uniform. `With slots 48 and 50 designed as just referred to therefore, a tube will be produced with a uniform taper and thickness of wall. It will be apparent that either or both of these grooves may have their longitudinal inclinations uniform, varied in degree or reversed, or without inclination,.i. e. in one plane normal to the tube axis, so that the mandrel and swaging members may be moved at any desired rate, from zero up, and in either direction, at any stage of the drawing operation.

It will thus be seen that by suitably designing the slots 48 and 50 the tube operated upon may be given any desired overall diameter and any desired thickness of wall at the section under the working members. The exterior of the tube may therefor be made to taper in one direction or iiiay be tapered first in one direction and then in the other and in varying or uniform degrees in both eases. Also the thickness of the wall may be tapered to any degree in one direction or the other and also be reversely taextreme rightV pered, or the wall may be of uniform thickness.

The use of cams for deining the positions of the various parts insures the accuracy of this positioning and also accuracy and excellence of product. This is particularly essential where very thin tube, such as is used for golf shafts, is the product.

The shaft 18 and swaging members revolve rapidly. The stroke of each of these members under the action of the hammer rolls is only a few thousandths of an inch and the tube is drawn forward at a comparatively slow rate sol that the amount of surplus metal drawn under the swaging tool at any instant is very small. It will alsocbe observed that the working face of the swaging tool slopes outward at the rear Aof the innermost point of the face of the tool so that ample clearance is provided between it and-the mandrel for the surplus metal to move rearwardly and at the same time the tool works against the shoulder of the metal to force it rearwardly. The result is that all surplus metal is forced to the rear and the tube comes out of the forward side of the swaging head with good texture and iinish and of desired dimensions.

It is to be observed that the operating means for the swaging members, mandrel and drawhead are interconnected so that at any moment these parts have definite, predetermined relations and with proper design and adjustment as hereinbefore set forth, tube of predetermined desired characteristics will be produced. p

In order that the tube may operated upon by the swaging tools at all points about its circumference, the gripping means is rotatable in the drawhead. Thus `the clamping block 12 is rotatably mounted in the drawhead. A thrust collar 72 upon this block, and having a ball bearing, is adapted to take the thrust due to the pull onV the tube during the draw. The circumferential impulse given the tube by the swaging members will ordinarily be sufiicient to give the tube the desired rotation but this may be effected by independent driving means such as a degree gear 73 fixed on a shaft 74 which is an extension of the clock l2 and which engages with a suitable rack 75 fixed on the frame so that as the drawhead moves with the drawing operation the block 12 and tube clamped thereto will be rotated. l

It is to be observed that the swaging members in the machine shown are greater in number than four. It has usually been considered sutlicient to employ four swaging members to act on the work -at the four cardinal points in operating to produce cylindrical (of uniform diameter) Work, and even two members have been` so ernployed especially when the Working faces are concave. The members then having a uniform approach to the axis of the work, the working faces may be formed and dimensioned to fit the work and will so function during all longitudinal positions of the work with relation to the swaging head. When it is desired to taper the work however, the swaging members come closer together as they more closely approach the work axis in operating on work sections of less diameter, as compared with their relative positions in operating on larger diameters of the work. The clearances between the members must be such `that they do not interfere with each other at their closest approach to the work axis. Compliance with this condition where there are four or less members and any considerable taper would result in such great clearances between the members in operating on the largest diameters of work that the metal would unduly extrude between the members and interfere with the swaging operation and the excellence of the product. While providing the necessary aggregate clearances between the members the present invention contemplates the employment of a number of swaging members such that the clearance between two adjacent members is sufficiently narrow to prevent undue extrusion of the metal between the members and avoid the disadvantages as above indicated. Vith the usual size and taper of golf shafts it has been found that live or more swaging members (six are shown in the drawing) give satisfactory results.

In the structure shown in Fig. l, the mandrel and the swaging tool wedges are moved by independent slides 30 and 36 so that they may have any desired relative movement to determine the thickness of the tube wall. The wedges and mandrel may however, be engaged by a single slide and moved together, the surface of the mandrel being designed to produce the desired wall thickness. Thus while in the apparatus of Fig. l the thickness of the tube wall can be increased by increasing the longitudinal movement of the mandrel with relation to the inward approach of the swaging members, the same result can be attained when both the mandrel and swaging members are operated by a single slide, although their relative movement is thereby limited, by employing a mandrel with a nose having a hollowed face 7G as shown in Fig. 7, wherein it is apparent that a given longitudinal mov-.ement of the mandrel from its initial position will produce a greater variation in thickness of tube wall thanv the same movement of the mandrel in Fig. l.

l/Vhile the invention of apparatus has been illustrated in what is considered its best application, it may have other embodiments without departing from its spirit and is not therefore limited to the structures shown in the drawings; also an illustrative manner of racticing the method has been recited in etail in connection with the apparatus shown. It is to be understood however that it may be practiced with other apparatus and lis not limited to the precise details recited.

What I claim is:

l. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, means for intermittently driving said members toward the axis of the tube, means for relatively rotating the said members and tube, means for passing the tube beneath said members, means for varyin the approach of said members to said axis under the action of said driving means in predetermined ratio to the passage of the tube beneath said members and a rotatable mandrel adapted to support said tube under said members.

2. Tube forming apparatus comprising in combination a swaging head including a /plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to the axis of the tube under the action of said driving means and a mandrel adapted to `present varying diameters for cooperation with said swaging members and means for operating said mandrel to present said varying diameters.

3. Tube forming apparatus comprising 1n combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, means for intermittently driving said members toward the axis of the tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present varying diameters for cooperation with said swaging members and means for interconnecting said approach varying means and said mandrel to operate in predetermined relationship.

4. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, means for intermittently driving said members toward the axis of the tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means,

a mandrel adapted to present different diameters for cooperation with said swaging members and a common means for operating [said mandrel and said approach-varying means.

5. Tube forming apparatus comprising in combination a swa ing head including a plurality of radia ly vibrating swaging members distributed about the tube position, means for intermittently driving said members toward the axis of said tube, meansfor passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said drivin means, a mandrel adapted to present di erent diameters for cooperation with said swaging members and means for interconnecting said tube passing means, said approach-varying means and said mandrel whereby they operate in predetermined relationship.

6. Tube forming apparatus comprising in combination a swaging head including a vplurality of radially vibrating swaging members distributed about the tube position, means for intermittently driving said members toward the tube axis, means for passing the tube through said head, means for varying the approach of said members to said axis under the action of said driving means2 a mandrel adapted to present different diameters for cooperation with said swaging members and a common means for Operating said tube passing means, said approach varying means and said mandrel.

7. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the tube position, means for intermittently driving said members toward the tube axis, means for passing a tube through said head, means for varying the approach of said members to said axis under the action of said driving means, a mandrel having a' tapered portion adapted to cooperate with said members and means for moving the mandrel longitudinally of said axis.

8. Tube forming apparatus comprising in combination a frame, a shaft rotatably mounted therein, radially vibrating swaging members mounted thereon, means for rotating said shaft, a member mounted on said frame, surrounding said swaging members and having projections adapted to contact said swaging members to force them inwardly, means for varying the radial length of said swaging members including rods extending longitudinally of said shaft, camming means for moving said rods longitudinally of said shaft, a mandrel extendin through said shaft and having a tapere portion cooperating with said swaging means, camming means for moving said mandrel endwise, a drawhead, a feed screw for moving said drawhead along said frame and a common driving means for both said camming means and said feed screw.

9. In a swaging head, the combination with a support o? a plurality of radially 'reciprocating swaging members on said support, each of said members comprising a wedge-shaped part movable transversely of the member to vary the length of said niember, said wedge-shaped part being secured to an adjacent part of the swaging member to permit said transverse movement but preventing radial separation of the parts.

10. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the tube position, means for intermittently driving said members toward the tube axis, means for varyin the approach of said members' to the axis of the tube, means for passing the tube through said head, a mandrel having different diameters and means for moving said mandrel to present different diameters to the tube under a given section of said members.

11. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, each of said members having its working face longitudinally convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to the axis of the tube under the action of said driving means and a mandrel adapted to present varying diameters for cooperation with said swaging members and means for operating said mandrel to present said varying diameters.

12. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, each of said members having its working face transversely convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means Jfor varying the approach of said members to the axis of the tube under the action of said driving means and a mandrel adapted to present varying diameters for cooperation with said swaging members and means for operating said mandrel to present said varying diameters.

13. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, each of said members having its working Jface longitudinally and transversely convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to the axis of the tube under the action of said driving means and a mandrel adapted to present varying diameters for cooperation with said swaging members and means for operating said mandrel to present said varying diameters.

14. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, each of said members having its working face longitudinally convex, means for intermittently driving said members toward the axis of the tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present varying diameters for cooperation with said swaging members and means for interconnecting said approach varying means and said mandrel to operate in predetermined relationship.

15. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swagin members distributed about the position o the tube tobe operated upon, each of said members having its working face transversely convex, means Jfor intermittently driving said members toward the axis of the tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present varying diameters for cooperation with said swaging members and means for interconnecting said approach varying means and said mandrel to operate in predetermined relationship.

16. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, each of said members having its working face longitudinally and transversely convex, means for intermittently driving said members toward the axis of the tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present varying diameters for cooperation with said swaging members and means for interconnecting said approach varying means and saidmandrel to operate in predetermined relationship.

17. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the tube position,

each of said members having its Working face longitudinally convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present different diameters for cooperation with said swaging members and means for interconnecting said tube passing means, said approach-varying means and said mandrel whereby they operate in predetermined relationship.

18. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the tube position, each of said members having its Working face transversely convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present different diameters for cooperation with said swagiiig members and means for interconnecting said tube passing means, said approach-varying means and said mandrel whereby they operate in predetermined relationship.

19. Tube forming apparatus comprising inl combination a swaging head including a plurality of radially vibrating swaging membersdistributed about the tube position, each of said members having its working face longitudinally and transversely convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present dilferent diameters for cooperation with said swagging members and means for interconnecting said tube passing means, said approach-varying means and said mandrel whereby they operate in predetermined relationship.

20. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon each of said members having its working'face globularly convex, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to the axis of the tube under the action of said driving means and a mandrel adapted to present varying diameters for cooperation with said swaging members and meansfor operating said lmandrel to present said varying diameters;

21. Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the position of the tube to be operated upon, the number of saidmembers being greater than four, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to the axis ot the tube under the action of said driving means and a mandrel adapted to present varying diameters for cooperation with said swaging members and means for operating said "mandrel to present said varyeters for. cooperation with said swagingV members and means for interconnecting said approach varying means and said mandrel to operate in predetermined relationship.

y 23. .Tube forming apparatus comprising in combination a swaging head including a plurality of radially vibrating swaging members distributed about the tube position, the number of said members being greater than four, means for intermittently driving said members toward the axis of said tube, means for passing the tube beneath said members, means for varying the approach of said members to said axis under the action of said driving means, a mandrel adapted to present different diameters for cooperation with said swaging members and means for interconnecting said tube passing means,

said approach-varying means and said mandrel whereby they operate in predetermined relationship.

In testimony whereof I have signed this specification this 22nd day of August, 1924.

FRIEDERICH MLLER.