US2870522A - Apparatus for manufacturing tubing - Google Patents

Description

Jan. 27, 1959 c. E. HlCKMA-N ET AL 7 APPARATUS FOR MANUFACTURING TUBING Filed Sept. 5, 1951 I I v 5 Sheets-Sheet 1 I1E=E INVENTOR. 1

CHARLES E. HICKMAN y ALLEN L. GOLDSMITH Jan. 27, 1959 c. E. HICKMAN ET AL 2,870,522

' APPARATUS FOR MANUFACTURING TUBING Filed Sept. 6, 1951' 3 Sheets-Sheet 2 Ila-=4.-

/ 'i z I 76: 74, ll

i III-31.7

F15 INVENTOR.

CHARLES E. HICKMAN By ALLEN LGQLDSMITH Jan. 27, 1959- E. HICKMAN ET AL APPARATUS FOR MANUFACTURING TUBING Filed Sept. 6, 1951 3 SheetsSheet 3 CHARLES E. HICKMAN BY ALLEN LGOLDSMITH United States Charles E.'Hickman and Allen L. Goldsmith, Adrian, Mich.

Application September 6, 1951, Serial No. 245,404

'5' Claims. (CI. 29-33) v This invention relates to apparatus for continuously forming and coiling small diameter thin wall metal tubing, and hasparticular .reference to a process and apparatus operable to produce a continuous, free ended coil of extruded metal tubing, such as aluminum tubing, which closely approximates the dimensional tolerances and wall thicknesses of cold drawn tubes but without requiring a drawing operation.

Normally the length of material issuing from an ex trusion press is limited to the length of the run out table extending from the mouth of the press. The run out table in turn is limited by the physical size of the building and the practical limits on the length of the material which may be conveniently handled without damage. In most shops this would be from seventy to one hundred feet.

Because of the variations in the speed of issuance from an extrusion press of a material such as small size, relatively thin wall tubing, even with uniform pressure upon the billet of metal from which the material is made, it is customary in the trade to employ persons known as pullers who grasp the emerging end of the tube as it comes from the press with suitable clamps and proceed along the side of the run out table applying enough tension to keep the tube from kinking but not enough to cause it to separate.

There are several variables which have an influence upon the uniformity of the speed with which such material may be extruded: namely, the temperature to which the billet is heated, the temperature to which the conv.tainer which holds the metal as it is being pushed into the die is heated, the varying length of the billet as it is being extruded, and the pressure which is exerted upon the billet as it is being extruded, to name but a few.

'Becausethe resulting tube represents such a small part of the-initial billet, very slight changes in temperature and forces acting upon the billet will cause such variations in the speed of the tube as it issues through the die that it is impractical to use constant speed-mechani- -.ca lmeans to supplantthe puller.

, This invention contemplates a methodof and apparatubing and being driven so as to exert a constant pull onthe tubing so as to follow the-instantaneous change Lin speedof the tubing as itemerges from the press.

=A. principal object of the invention, therefore, is to provide anovel methodof and-apparatus for continuously formingand-coiling small diameterthin wall metal tub- .rifl .such as. aluminum'tubing, Without the necessity of a drawing operation.

1 v gAnotherv object of the invention is to-providea method of and apparatus for coiling small diameter thin Wall :tubingin helical coils with a free end.

. Another; object of the inventionis toprovide a method Patented Jan. 27, 9

2 of and apparatus for rapidly cooling extruded metal tubing so that such tubing may be handled without damage to the tubing and without the tubing sticking to itself or burning materials in contact with it.

Other and further objects of the invention will be ap parent from the following description and claims and may be understood by reference to the accompanying drawings, of which there are three sheets, which by way of illustration show a preferred embodiment of the invention and what we now consider to be the best mode in which we have contemplated applying the principles of our invention. Other embodiments of the invention may be used without departing from the scope of the present invention as set forth in the appended claims.

In the drawings:

Fig. 1 is a fragmentary sectional view of an extrusion press embodying our invention;

Fig. 2 is an enlarged fragmentary sectional view of the die parts in the coalescence chamber;

Fig. 3 is a fragmentary sectional view of the cooling device;

Fig. 4 is a plan view of the cooling device shown in Fig. 3;

Fig. 5 is a side elevational view of the coiling device;

Fig. 6' is a plan view of the coiling device. shown in Fig. 5; and

Fig. 7 is a schematic illustration of the control system for the direct current motor which drives the coiling device.

The apparatus embodying our invention comprises in general an extrusion press 10 (Fig. l), a tube cooling device 12 (Fig. 3), a coiling device 14 (Fig; 5), the, latter being provided with means including a direct current motor 16 for driving the rollers of the coiling device so as to exert a constant pull on the tubing as it emerges from the extrusion press.

As shown in Figs. 1 and 2, the press comprises in general a platen 20 having an'opening through which the die holder 22 extends, the die holder22 being secured in position against the, platen 20 by the reciprocable die locks 24. A die backer 26 and die housing 28 are positioned in a cavity in the die holder 22. The backer 26 and housing 28 are securely fixed as illustrated relative to each other and to the cylinder 30 so that the billet of metal 32 in the cylinder 30 will flow under the influence of heat and pressure into the coalescence chamber 34.

The coalescence chamber 34 comprises an annular chamber formed by hollowed out portions of the backer 26 and the housing 28, the latter being provided Witha plurality of cylindrical passages'36 aifording communication between the chamber 34 and the cylinder 30. The passages 36 are symmetrically arranged parallel to the axis of the chamber 34. The cylinder 30 is formed in a cylinder block 38 which as arranged in Figs. 1 and 2 abuts the die housing 28.

Pressure is applied-to the billet 32 in the cylinder 30 by means of a seal plug 40 and a ram 42. As is customary, the die parts, the billet, and the containing cylinder are maintained at suitable temperatures during operation of the press, and pressure is applied by the ram 42 to the billet 32 to cause it to flow, the pressure required being dependent to some extent upon the temperature to which the parts are heated and being of the order of 100,000 lbs. per square inch.

The backer 26,whichforms one wall of the coalescence chamber 34, is provided with a circular opening 44 disposed concentrically relative to the axis of the chamber 34 and through which opening the metal to be extruded flows in the form of a hollow tube 46. An annular die member 48 of hard material, such for-example as tungsten carbide, is seated against the face of the backer26 and disposed around the opening 44 and fonns a die for determining the outside diameter of the tubing to be extruded. While the die member 48 is seated in a recess in the backer 26, it may have a loose or floating fit therein so that it is free to shift in a plane normal to the axis of the chamber 34.

The hub 56 of the housing 28 is provided with a socket 50 which loosely receives the base 52 of the core so that the core 54 has a loose or floating support on the hub 56 of the housing 28. The core is disposed on tne axis of the chamber 34 and projects into the an :ir die 48 in spaced relation therewith so as to form annular opening between the core 64 and the die 43.

The metal to be extruded flows from the cylinder through the passages 36 into the chamber 34 pletely fills the same. In the chamber 3 th alesces and completely fills the chamber and the core and the metal flows from the charn between the core 54 and the die 48 to form the sear iess extruded tubing 46.

While the core 54 has a loose fit in the socket 5-5 it is held in piace by the pressure which the metal in chamber 3 exerts upon the base 52 of the core 54-. The pressure exerted by the metal in the chamber 34 as it flows through the annular opening between the core 54 and the die it; tends to cause the core 5-ito center itself in the annular opening in the die 48. if the die is also free to float, the pressure exerted by the metal in the chamber A as it flows through the annular opening between the core 54- and the die 48 will also tend to cause the die 4? to center itself with respect to the core 5d. The core 54 may also, if desired, be formed of hard material, such as tungsten carbide.

As the billet 32 is used up, the seal plug 41 moves within a predetermined distance of the die housing 2'5. At this time the cylinder block 3%, which is moved by a hydraulic piston and cylinder unit (not shown), is caused to move away from the surface of the housing 28 and over the outer surface of the part of the billet remaining in the cylinder 30 and also over the seal plug 40 until the remaining metal of the billet, usually referred to as the butt, and the seal plug 40 are exposed. The ram 42, which is also actuated by a hydraulic piston and cylinder unit (not shown), is retracted and the shear blade 58 actuated by the power cylinder 59 is moved downwardly across the exposed rear face of the die housing 28, thereby separating the butt from the housin and permitting the butt and seal plug 40 to fall out of the Way. The cylinder block 38 is then brought forward into contact with the rear face of the die housing 23, another billet is introduced into the cylinder 30, the seal plug is replaced, and the ram 42 is advanced for another cycle. As the metal of the billet is again forced into the holes 36 of the die housing, because of the pressure to which the metal is subjected it comes into intimate cohesive contact with that left within the die housing and all vestige of air is compressed and expelled, and the metal of the new billet becomes a homogeneous mass with that remaining of the one which preceded it.

It has been found more convenient to permit the die holder 22 to remain in position through several cycles or until it becomes necessary to remove the die parts. The die holder may be removed by causing the die locks to separate and then by pushing the die holder 22, the die parts 26 and 28, the butt, and the seal plug 40 through and away from the container by the continued forward movement of the ram 42.

In this instance the die holder 22 and the die parts and 2S are completely withdrawn through the opening in the platen 29 and the butt may then be sheared with a shearing mechanism (not shown) like 58 but mounted on the front side of the platen 2i). Following such op eration the ram 42 is then withdrawn, the container 3% moved back, the die holder 22 and the die parts carried thereby again introduced through the platen and locked All in place by the die locks 24. The container 33 is then brought forward in contact with the rear face of the die housing, a new billet is introduced into the cylinder 30, and the operations continued as previously mentioned.

As shown in Figs. 1 and 2, the extrusion press is operable to form the hollow seamless tubing 46 and to discharge the same, the temperature of the extruded tubing as it leaves the die being in the neighborhood of 700 to ll0O P. if aluminum tubing is being formed. While the process and apparatus are particularly adapted for use in forming aluminum tubing, they may be used in connection with the formation of tubing of other metals, such for example as magnesium.

Speaking now about aluminum tubing, as it is extruded from the press it is so hot that it has insuflicient strength to withstand winding without collapsing, and it is readily subject to scoring and abrading and sticking to itself. it therefore is highly desirable to rapidly cool the tubing as it is extruded, and for this purpose we have provided the cooling device shown in Figs. 3 and 4. The cooling device comprises a tank 60 of cooling liquid, such as water, having tube entering and tube exit openings 62 and 64 arranged in line with and at the same elevation as the tubing as it is extruded from the press. As the tubing emerges from the press it passes through a series of slots 66 formed in a series of partitions 68, thence through the entrance opening 62 to the tank 60, thence through the tank 66, thence through the exit opening 64, and thence through another series of slots 70 formed in another series of partitions 72. The openings 62 and 64 to the tank 60 are formed by slots in the end walls '74 of the tank and by removable partitions 76 so that water may stand in the tank 6b to a higher level than the openings 62 and 64. The removable partitions 76 may be removed when the tubing 4-6 is first extended through the cooling device. Therefore, it is not necessary to thread the tubing 46 through the cooling device, but merely to lay it in the slots 66 and 7t and the slots in the end walls 74 which form the openings 62 and 64. Thereafter the partitions '76 may be inserted, leaving a slight clearance around the tubing so that water may flow from the tank 6! outwardly through the openings 62 and 64.

Water enters the tank 60 through the supply pipe 78 which communicates with a horizontally extending pipe 80 disposed below the tubing 46. Water is maintained at a predetermined height in the tank above the tube 46 by the overflow pipe 32 and by the labyrinth of weirs created by the slots 66 and 70 in the partitions 68 and 72. The partitions 68 and 72 form individual compartments, each of which has a restricted drain opening 84, in the bottom thereof. The partitions 68 and 72 are partially enclosed by troughs 86 to which drain conduits 88 are connected. The slots 66 and 76 in the partitions 68 and 72 have a fairly close fit around the tubing 46 but also provide sufiicient clearance to permit water to flow from the tank 60 through the slots 66 and 70 and around the tube so as to cool the same as it enters and leaves the cooling device. The partitions 76 limit the flow of water from the tank 60 around the tubing 4-6, and the water which does escape through the openings 62 and 64 spills seriatim intothe several compartments formed by the partitions 68 and 72, the water escaping from the compartments through drain holes 84. This labyrinth of weirs permits the water to escape from the tank at such a rate that it will not flow beyond the confines of the outermost partitions 68 and 72.

The horizontally extending pipe 80 functions as a distributor and is provided with a series of jets 90 for discharging jets of water against the tubing 46 as it moves through the tank 60, the jets functioning to dislodge the.

steam enveloping the tube and formed by the water as it is heated by the tube 46.

In one installation we have made the cooling device function to reduce the temperature of the aluminum tubing leaving the cooling device to approximately F. In this installation the tubing moved through the as'rosszz cooling device at speeds between 100and 300 feet per minute, depending upon the size ofthe tubing. With the size of the tubing being formed this would require cooling approximately twelve pounds of aluminum per minute 700 F.

From the cooling device the tubing 46 moves to the closely positioned coiling device shown in Figs. Sand 6. The coiling device includes two peripherally grooved drive rollers 92 and 94 arranged to receive the tubing 46 as it leaves the cooling device. The coiling device further includes a peripherally grooved forming roller 96 and two peripherally grooved retainer rollers 98 and 100. As the tubing 46 leaves the drive rollers 92 and 94 it passes through the groove of the forming roller 96 and then through the grooves of the retainer rollers 98 and 100, the rollers functioning to coil the tubing 46 into a helical coil, as indicated generally at 102 in Fig. 6, with a free end 104. A tube 106 rotatably supported in the movable block 108 projects horizontally and forms a support for the formed coil of tubing.

The gear 110 is mounted on a rotatable shaft 112 which is driven through coupling 114 by the D. C. motor 16, the shaft 112 being journaled in a bearing in the frame or plate 116. The gear 110 drives a gear 118 as Well as a gear 120, the drive roller 94 being connected to the gear 120 so as to rotate therewith. The gear 120, the roller 94, and the gear 118 along with the gear 110 are all rotatable about their own respective fixed axes.

The roller 92 is mounted for rotation with the gear 122 and on the same shaft 124, such shaft being carried by a block 126 which is pivoted to rotate around the same center as the gear 118, the gear 122 meshing with the gear 118 so as to be driven thereby. This arrangement permits the two drive rollers 92 and 94 which act directly upon the progressing tubing 46 to be separated and brought together at will without changing their speed with relation to each other, since they are both driven from the same gear 110. It is therefore possible to separate the rollers 92 and 94 so as to place the progressing tube 46 between them and to let the tube 46 enter the grooves in the rollers 96, 93 and 100. In so doing the apparatus may be adjusted so that the coil 102 thus formed will slightly clear the supporting roller 106.

The supporting roller 106 consists of a suitable size tube held at one end in the movable block 108 but free to rotate and supported a proper distance down its length by the rollers 128 carried by the supporting arm 130. The forming roller 96 and the retaining rollers 98 and 100 are all adjustably supported on the plate or frame 116 so that such rollers can be moved inwardly or outwardly, thus governing the diameter of the resultant coil. These rollers 96, 98 and 100 are also arranged to permit the plane of each of the rollers to be rotated about a horizontal axis. In this way the path o-fthe tube 46 as it moves through the rolls 96, 93 and 100 is governed to permit the resultant helical coil of tubing to be wound tight against itself, as illustrated, or separated if desired. The block 108 is also adjustable so as to shift the supporting roller 106 to the posi tion desired with respect to the size of the coil being formed.

The nature of the gear train driving the two rolls 92 and 94 is such that there is a tendency for the gear 118 to force the roll 92 down into contact with the lower tube drive roll 94. Since these rolls 92 and 94 are constructed so as to bear upon the tube before they bear upon each other, the tube passing between the rolls 92 and 94 would be considerably distorted unless this tendency was restrained. The work of distorting the tubing 46 because of this tendency is suificient within the limits of the power required to operate the device to completely stall its operation. The motion of the upper tube drive roll 92 toward the lower one is therefore restrained by means of an adjustable arm 132 which permits a predetermined amount of pressure upon the tube 'as it moves throughthe rolls. This arrangement permits automatic compensation for slight variation in the diameter of the tube so that during operation there is no slippage. The tube then progresses through the drive rolls 92 and 94 and against the form roll 96 and through the retainer rollsyand'proceeds to form itself into a helical coil along the support arm to whatever practical length is-required. When the desired length of coil is reached the tube may be cut at a point just after it has passed through the seriesof rolls, and the out ch? portion removed topermit another one to be formed.

In one setup We have rnade'the motor 16 for driving the tube coiling device a one-half horsepower direct current motor. This motor derives its power from the special type of motor generator set known commercially as an amplidyne. This amplidyne controls the current to the motor 16 so that the motor drives the drive rolls 92and' 94 with a' constant pull or torque on the tubing 46 as it emerges from the press so that the coiling device coils the tubing at the same rate as the tubing is extruded by the press. This is very important as the tubing as it emerges from the press and before it is cooled has 'very little resistance to damage and will buckle or stretch if the coiling device does not operate to coil the tubing at the same rate as it is extruded from the press. With this type of control for the D. C. motor, the drive rollers 92 and 94 will propel the tubing at the same rate that it emerges from the extrusion press, and speeds from zero velocity up to the maximumextrusionspeed in the neighborhood of 300 feet per minute have been satisfactorily handled without damage to the tubing with the control of the type referred to.

The control embodies provisions for setting the tension exerted by the drive rolls 92 and 94 on the tubing, and with the size of tubing we have made and coiled a selected tension between eight and fifteen pounds is usually employed. Once the control-has been set the tension remains constant even when the tubing is not being extruded, as for example when a new billet is being placed in the cylinder 30.

In the control system of the type indicated for the motor 16, the primary 200 of the transformer indicated generally at 202 is energized by the usual A. C. current supplied, and the transformer 202 in conjunction with the rectifier 183 furnishes the current to the field. 20 4 of the D. C. motor 16 connected across L2 and F1. The armature of the motor 16 is indicated at 206.

The amplidyne includes a generator having an armature 208 and a field 210, the amplidyne generator being driven by any suitable source, such as an electric motor (not shown). Line P4 of the amplidyne exciter field is connected to the positive side of the rectified voltage through the variable resistor 212. Line P5 of the amplidyne exciter field is the negative line through the 300 ohm potentiometer torque control 214, this being adjustable to set the torque that the driver rollers 92 and 94 will exert on the tubing 46. When the D. C. motor starts to draw the current through its field because of the increased load on the motor the voltage at point F1 is lowered, causing a difference of potential between the lines F5 and F4, which puts exciter voltage through the amplidyne field. This in turn causes the amplidyne to generate more voltage for the armature 206 of the D. C. motor and gives the D. C. motor more torque. As the load on the D. C. motor decreases, the voltage at point F1 of the D. C. motor field is raised, causing a smaller ditference of potential between lines F5 and P4 of the amplidyne generator which lowers the exciter voltage, which in turn lowers the voltage to the D. C. motor and reduces the D. C. motor torque. This control is extremely sensitive and responsive, and accurately controls the torque output of the D. C. motor 16 so that the drive rollers 92 and 94 will maintain a constant torque on the tubing 46 at all velocities within its range of speed.

While we have illustrated and described a preferred embodiment of our invention, it is understood that this is capable of modification, and we therefore do not wish to be limited to the precise details set forth but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

We claim:

1. A tube coiling device comprising a pair of cooperative peripherally grooved drive rolls, a forming and a series of retainer rolls arranged to coil tubing in the form of a free ended helix, one of said drive rolls being rotatable on a fixed axis, means freely mounting the other of said drive rolls for rotation about an axis shittable toward and away from said fixed axis, said drive rolls being arranged to receive said tubing in driving relation therebetween and being operable to propel said tubing past said other rolls, said mounting means having adjustable means to limit the movement of the axis of said other drive roll only toward said fixed axis so that said drive rolls will automatically space themselves to accommodate variations in the diameter of said tubing, common means for driving said drive rolls at the same rate of speed but in opposite directions, said last-mentioned driving means being constructed and arranged with respect to said mounting means for the shiftable drive roll so as to apply torque to said shittable drive roll in a direction to produce torque reaction of the shiftable drive roll which biases said shiftable drive roll toward the other of said drive rolls, and a horizontally extending arm freely projecting from said device and arranged to support said coil of tubing after it is formed so that a severed coil of such tubing may be freely removed with out interfering with the operation of said cooling device.

2. Apparatus for extruding, cooling and bending seamless metal tubing comprising a continuous ram type extruding press for hot extruding continuous metal tubing of constant diameter, a cooler adjacent said press having a free path through which the hot tubing is pulled as it is being rapidly cooled, shaped propulsion rolls for pulling said tubing through said cooler, means for driving said rolls for pulling said tubing at extrusion speed and so as to exert a constant and uniform pull on said tubing whereby the diameter or" said tubing remains constant and is fixed by rapid cooling, a tubing bending device comprising ofiset bending rolls, said. propulsion rolls moving said rapidly cooled tubing into and through said bending device, said bending rolls being disposed so as to apply bending pressure at spaced intervals on only one side of the tubing whereby said tubing maintains the constant diameter of said chilled tubing.

3. Apparatus according to claim 2 wherein said bending rolls are spaced and disposed so as to bend said tubing into a coil in the form of a helix of substantially uniform diameter and means arranged to receive and support the coil of tubing as it is being formed while leaving the leading end of said helix free.

4. Apparatus according to claim 2 wherein said cooler includes provisions for directing jets of cooling liquid against said tubing as it moves through said cooler.

5. Apparatus for extruding seamless metal tubing comprising a continuous ram type extruding press for hot extruding continuous tubing of constant diameter, shaped propulsion rolls engageable with said tubing after the diameter thereof as extruded has been fixed by cooling for pulling said tubing as it is extruded from the press, means for driving said rolls for pulling said tubing at extrusion speed and so as to exert a constant and uniform pull on said tubing whereby the diameter of said tubing as extruded remains constant, and a tubing bending device comprising otiset rolls, said propulsion rolls moving said cooled tubing into and through said bending device, said bending rolls being spaced and disposed so as to apply bending pressure at spaced intervals on only one side of the tubing so as to bend said tubing into a coil in the form of a helix of substantially uniform diameter while leaving the leading end of said tubing free and whereby the diameter of said tubing as extruded remains constant and fixed.

References Cited in the file of this patent UNITED STATES PATENTS 278,695 Farrell June 5, 1883 278,696 Farrell lune 5, 1883 403,940 Kerr May 28, 1889 972,928 Schneider Oct. 18, 1910 1,028,102 Erickson June 4, 1912 1,417,249 Kardong May 23, 1922 1,561,577 Trautman Nov. 17, 1925 1,741,815 Boynton Dec. 31, 1929 1,769,205 Clark July 1, 1930 1,782,692 Lawson Nov. 25, 1930 1,849,044 Summey Mar. 8, 1932 2,048,557 Mickelson et a1 July 21, 1936 2,167,971 Gadden Aug. 1, 1939 2,176,365 Skinner Oct. 17, 1939 2,291,204 Betterton July 28, 1942 2,347,639 Platt Apr. 25, 1944 2,359,453 Waldron Oct. 3, 1944 2,377,908 Slaughter June 12, 1945 2,453,165 Thornburgh Nov. 9, 1948 2,720,310 Yack Oct. 11, 1955 FOREIGN PATENTS 284,085 Great Britain Jan. 26, 1928 410,624 Great Britain May 24, 1934 593,508 Great Britain Oct. 17, 1947 646,296 Great Britain Nov. 22, 1950 660,747 Great Britain Nov. 14, 1951

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