US3010575A - Extrusion puller - Google Patents

Description

Nov. 28, 1961 B. F. SMITH EXTRUSION FULLER 2 Sheets-Sheet 1 Filed Aug. 15, 1956 INVENTQR. Be /am/n F Sm/fh ,3 WM Afforney B. F. SMITH EXTRUSION PULL Nov. 28, 1961 2 Sheets-Sheet 2 Filed Aug. 15, 1956 INVENTOR. Benjamin F Smi/h United States Patent'O 3,010,575 EXTRUSION PULLER Benjamin F. Smith, Grand Rapids, Mich, assignor to Light Metals Corporation, Grand Rapids, Mich, a corporation of Michigan Filed Aug. 15, 1956, Ser. No. 604,270 2 Claims. (Cl. 2071) This invention is related to the construction of equipment used in the extrusion of metals. In this process, a billet of metal such as aluminum, magnesium, or occasionally brass, is heated to a plastic or semi-plastic state, and placed in a recess in the extrusion die. Usually, a ram driven by hydraulic forces enters the recess, and forces the material of the billet out through a series of holes having a particular cross section. As the metal extruded through these holes continues to flow under the pressure of the ram, a long strip of material having substantially the same cross section as the die opening is developed, and the strip may may well run to from ten to a hundred feet in length, depending upon the number of openings in the die, the size of the billet of metal, and the cross section of the extruded strip. It is conventional practice to provide a run-out table in conjunction with an extrusion press, which is essentially a horizontal table extending a sufiicient length from the press to accommodate the extrusions to be formed. The extrusions are forced out on a substantially horizontal axis at a height such as to be readily received on the table.

Due to the fact that the strips emerging from the extrusion die are still very hot, and are consequently still in a pliable state, it has been the general practice to instruct a worker to grasp with a clamp the emerging end of the extrusion as it begins to develop in the die, and exert a gentle pull during the entire extrusion operation. This pull is directed in such a fashion that the extrusion will tend to follow out along the run-out table in a relatively straight line. Were it not for the presence of the worker, the friction of the extruded piece as it is shoved out of the die onto the table would tend to buckle it axially so that it would assume a serpentine configuration while still in a pliable form. When it once had cooled, the strip becomes set in that pattern, and the straightening operation which must then be performed on it becomes quite extensive. It should also be kept in mind that when a straight piece assumes a serpentine form, the lateral space occupied by it is greatly multiplied. In extrusion dies having closely-grouped holes, it is vital that the several strips emerging from the die be kept isolated one from the other to avoid interference and entanglement. Maintaining each strip in a straight line therefore becomes a vital necessity, even when a subsequent straightening operation is secheduled. V

The replacement of the Worker, who pulls the extrusion as it emerges and guides it out along the run-out table, by a mechanical device is not broadly new. The W. A. Yack et al. Patent 2,720,310 illustrates a mechanical device for performing this function, and provides for the application of a constant pull regardless of the velocity of emergence of the extruded strip. In connection with this feature, it should be noted that the natural velocity of the various strips as they emerge from a single die may not be the same, and may be altered by several factors. The billet of material may easily contain spots within its mass which are less plastic than the surrounding areas, and the engagement of such a collection of material of greater solidity with one of the extrusion openings will tend to slow down the rate of emergence of the material from that opem'ng. It is also true that no two openings in the extrusion die are identical in form, and the resistance to flow through the various openings will always have some minute variation. Even the smallest difference will ments illustrated in the accompanying drawings.

tend to cause a differential in the velocity of extrusion of the respective strips, and will illustrate the necessity either of (a) applying a sutficient tension to all of the strips held in one clamping system to actually speed up the lagging strips so that all move with the same velocity, or (b) applying a separate tension force to each strip which is constant over considerable changes of velocity.

This invention derives the pull-out force from the action of a piston travelling in a long cylinder preferably arranged parallel and in close proximity to the run-out table. The length of the cylinder is substantially the same as the length of the extrusion path, and a flexible member such as a wire or cable preferably extends both ways in the cylinder from the piston, passes around suitable pulleys at the opposite ends of the device, and is connected to a carrier riding on a suitable track associated with the run-out table. A clamping device connected to this carrier is adapted to engage the extrusions as they emerge from the die, and the application of air pressure to one side of the piston within the cylinder results in the force of the air pressure being transmitted directly through the cable over its single pulley to the carrier, suitable cylinder head plugs being provided at the opposite ends of the cylinder with appropriate openings for passage of the cable. The draw bench art contains several examples of the use of fluid pressure to motivate a carrier coupled to a piece being pulled, but each of these involves multiple-strand pulley arrangements for increasing the rate of movement of the carrier with respect to that of the piston. The friction and mechanical resistance of these multiple-strand arrangements has resulted in a device which is not as responsive to variations in extrusion velocity as may be desired, even though the pressure applied to the units is constant as a result of the conventional pressure-accumulator tank and regulator arrangement.

While the endless belt or cable system for transmitting the movement of the piston to the carrier is not new (refer to the Panashe Patent No. 1,516,618), applicant has provided features in this invention relating to the formation of the cylinder with respect to a horizontal plane which facilitate the lubrication of it throughout its length, and consequently make possible the utilization of a piston moving directly with the carrier. The pulling action applied to the carrier is transmit-ted through the resilient air column under pressure, which tends to maintain the constancy of the force even though the air supply to the cylinder may include fluctuations in velocity.

The several features of the invention will be analyzed in detail through a discussion of the particular embodi- In the drawings:

FIGURE 1 presents a schematic diagram showing the pneumatic circuit and the included control and gaging arrangements.

FIGURE 2 presents a schematic diagram showing the components of the puller system in conjunction with an extrusion run-out table.

FIGURE 3 presents a section on an enlarged scale from that of FIGURE 2, and illustrating the relationship of the cylinder, carrier guideway, and tension cable.

Referring first to FIGURE 2, an extrusion press is indicated generally at 10, in which a die 11 is mounted. The extruded strip 12 is emerging from the opening of the die 11, and is grasped by the manually-operated clamping means or clamp 13 through which the pullout forces are applied. As the strip 12 continues to emerge, it will become supported on the surface of the run-out table 14. The clamp 13 is preferably of a self-locking variety of common construction, and is mounted on the carrier generally indicated at 15. The carrier itself may be of any convenient construction, and is supported by 3 the guideways or trucks 16 and 17 which engage the bottom flanges 18 and 19 of the channels 20 and 21 as indicated in FIGURE 3. The trucks indicated at 16 in FIGURE 2 are shown as 16a and 16b in FEGURE 3,

since they are duplicated on opposite sides of the device. The same construction is followed in the case of'the trucks 17. The channels 29 and 21 serve as tracks and also as supporting beams which establish apath of movement of the carrier adjacent to the run-out table 14, and preferably parallel with it. The beams and 21 may be considered a fixed with respect to the run-out table 14 by any convenient structure (not shown) which may be 'varied to suit the needs of each particular installation. I

A flexible tension transmission means such as cable or wire 22 is connected to the carrier 15, and extends around the pulleys 23 and 24. From these points, the cable 22 extends through the elongated cylinder 25 to the piston assembly 26, best shown in FIGURE 1. The cylinder 25 is arranged as will be evident by the description hereinafter to confine gas into an elongated gas column under pressure which exerts a force on either side of the piston assembly 26. The cylinder 25, piston 26, the pneumatic system, hereinafter described, and cables 22 produce a for-cc application means connected to the clamping mews 13 for transmitting a pulling action on an extrusion. In the illustrated arrangement, the cable 22 is actually two separate pieces, but this arrangement is by no means critical. The tension in the cable 22 is preferably made adjustable by mounting the pulleys 23 and 24 on an adjustable bracket carried by the uxiliary beam 27. The bracket indicated generally at 28 is slideable with respectto the auxiliary beam 27, and is positioned through the adjustment of the bolt 29. If sufiicient range of the adjustment is desired to warrant this construction, it may be duplicated at the opposite end of the device.

A pair of brackets 36 and 31 are disposed at opposite ends of the cylinder 25, respectively, and position the cylinder with respect to the channels 29 and 21. Suitable cylinder head means such as plugs 32 and 33 close olf the ends of the cylinder 25, except for openings provided for the passage of the cable 22. The cylinder 25 is mounted so that it will sag somewhat in the center, resulting in the fact that the opposite ends of the cylinder are elevated slightly from a horizontal plane tangent to the central portion. The purpose of this arrangement is to facilitate lubrication of the leathers 34 and 35 of the piston assembly 26. Lubrication of the unit becomes a considerable problem as a result of the length of the cylinder 25, which may commonly run in excess of seventy-five feet. Tension in the cable 22 will result in a portion of the central part of the cylinder being brushed by the cable 22 during its movements, and will thereby Serve to supply small quantities of lubricant which have become attached to the cable in the form of small droplets projwtcd into' the cylinder by the pneumatic system.

The pneumatic system responsible for the movement of the piston communicates with the general pressure source conduit indicated at 36, which is connected directly to the pressure regulators 37 and 38 by the pipes 39 and 40, respectively. Pressure gauges are preferably provided as indicated at 41 and 42 in both branches on the circuit, from which the flow of air under pressure is conducted to the solenoid-operated valves 43 and 44. Wiring for the control of the solenoid valves 43 and 44 is carried by the conduits 45, 46, and 47, as shown in FIGURE 2. The Wiring details of this system are shown best in FI URE l, which show the solenoids 48 and '49 controlled by the switch 50 so that closure of the switch will result in energizing both of the solenoids simultaneously against the action of the springs 51 and 52, as shown.

On closure of the switch 50, the valve member 53 of the solenoid valve 43 moved to the right, and

permits pressure to enter the pipe 54. As a result of the presence of the check valve 55, air pressure does not flow toward the cylinder 25 through the conduit 56, but takes the path which includes the filter 57, the lubricating means or oiling unit 58, and the check valve 59. From this point, it enters the cylinder 25 through the pipe 6% The closure of the switch 5'9 has resulted in the movement of the valve member 61 of the solenoid valve 44 to the left, which blocks the entrance of pressure flow from the conduit 40, and establishes a path for the fiow of air from the pipe 62 out through the exhaust port 63. As a result of the presence of the check valve 64, no exhaust flow passes through the oiler 65 or the filter 66 but flow moves freely through the check valve 67. On opening of the switch 50, the springs 51 and 52 position the valve members 53 and 61 at the opposite extreme of their strokes, and reverse the application of pressure and exhaust connections to the cylinder 25, and induce opposite movement to the piston assembly 26.

An interesting possibility associated With this invention is the fact that the elongated cylinder 25 can be extruded on the same press with which the puller device is to be incorporated. This procedure removes the difficult problem of handling and maintaining the straightness of a tube of this length, and makes it possible to tailor the tube to the needs of the press with a minimum of difiiculty.

In addition to the problem of applying a tension force to the emerging extrusion, it is ordinarily necessary to apply a sudden and severe jerk to the extrusion at the end of its stroke to pull it free of the die opening. This invention provides an arrangement for applying such a force through the use of a weight 68 (refer to FIGURE 2) mounted on a separate truck 69 which moves along the channels 21 and 20 when manually or automatically projected. The truck 69 is not connected to the cable 22. When the carrier 15 has reached the end of its pullout stroke, and is positioned toward the left end of the device as shown in FIGURE 2, the weight 68 may be given a shove down the guideway, to a point of collision with the cushioning block 70. The net result is similar to a hammer blow, and when transmitted to the extrusion through the carrier 15 and the clamp 13, will ordinarily jerk it free of the die 11. On the return of the carrier 15, the weight 68 is restored to the postion illustrated in FIGURE 2.' A workman standing adjacent the die during the extrusion operation will be in appropriate position to shove the weight at the proper time.

It is recommended that the cushioning springs 71 and 72 be included in the piston assembly 26 to prevent damage as the unit reaches the end of the stroke. The remainder of the piston assembly may be of any conventional construction, the illustrated form including the rod 73 threaded and transversely slotted at both ends. Washers 74 and 75 position the sealing leather 34 and are held in position by the nuts 76 and 77. Similarly, the washers 78 and 79 position the leather 35, and are held by the nuts 80 and 81. The ends of the cable 22 are formed into loops by the clips 82 and 83 respectively, which are received in the slotted ends of the rod 73 and anchored by cross pins as shown at 84.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the appended claims. In these claims, it is my intent to claim the entire invention disclosed herein, except as I am limited by the prior art.

I claim:

1. An extrusion apparatus comprising: an extrusion press including a die and structure to force metal to extrude through said die; a run-out table over which the extruding product passes; an overhead carrier movable above the extrusion path along the length thereof, said carrier riding stationarily fixed rails and having an extrusion gripping clamp suspended below said carrier and between said rails and intersecting said path; a flexible tension device, the latter being attached to the fore and aft ends of said carrier and extending over two rotatably mounted sheaves, each one of the latter being located near a corresponding end of said path and thereabove; motive power means operatively connected to said tension device for exerting a pull thereon selectively in a fore or aft direction for moving the carrier in said directions; a carriage distinct from said carrier, being on the press side thereof, and riding said rails, said carriage having a weight suspended therefrom between said rails in a location where said weight can strike against an abutment on said carrier; whereby, said clamp is clamped on the end of an emerging said product, force is applied by said motive power means pulling said tension device over the far sheave and pulling said carrier and said clamp away from said press which results in tension being applied to said product during the extrusion thereof; and whereby, near the end of the extruding, said carriage is impelled along said rails causing said Weight to strike said abutment to jerk said product from said die.

2. An extrusion apparatus comprising: an extrusion press including a die and structure to force metal to extrude through said die; a run-out table over which the extruding product passes; an overhead carrier movable above the extrusion path along the length thereof, said carrier riding stationan'ly fixed rails and having an extrnsion gripping clamp suspended below said carrier and between said rails and intersecting said path; a flexible tension device, the latter being attached to the fore and aft ends of said carrier and extending over two rotatably mounted sheaves, each one of the latter being located near a corresponding end of said path and thereabove; an elongated cylinder stationarily mounted between said sheaves, the ends of said cylinder allowing said tension device to slide therethrough but being sealed air tight around said tension device, said cylinder being mounted clear of the course of travel of said carrier, said ends of said cylinder each being adjacent to a fluid opening for the respective admission and exhausting of driving fluid into and out of said cylinder; a piston assembly movable within said cylinder in response to differences in pressure therein; said tension device being attached to the fore and aft ends of said piston assembly and being of continuous extent from each of the latter ends to a corresponding one of said fore and aft ends of said carrier; a carriage distinct from said carrier, being on the press side thereof, and riding said rails, said carriage having a weight suspended therefrom between said rails in a location where said weight can strike against an abutment on said carrier; whereby, said clamp is clamped on the end of an emerging said produd, fluid pressure is applied at the far end of said cylinder and exhausted from the near end thereof causing said piston assembly to move towards said press thus pulling said tension device over the far sheave and pulling said carrier and said clamp away from said press which results in tension being applied to said product during the extrusion thereof; and whereby, near the end of the extruding, said carriage is impelled along said rails causing said weight to strike said abutment to jerk said product from said die.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Jan. 26, 1928

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