Patent Publication Number: US-3875781-A

Title: Press for producing closed-bottomed articles

Description:
[ Apr. 8, 1975 i 1 PRESS FOR PRODUCING CLOSED-BOTTOMED ARTICLES [75] Inventors: Franz Josef Zilges, Rheydt; Heinrich Kutz. Neuss. both of Germany [73] Assignee: Schloemann-Siemag Aktiengesellschaft. Dusseldorf. Germany 22 Filed: May 3, [974 2&#39;1 Appl.No.:466,863  
 [30] Foreign Application Priority Data May 7, 1973 Germany 2322868 [52] US. Cl. a. 72/257; 72/267; 72/263; 72/272. 72/273 [51] Int. Cl. BZlc 23/18 [58] Field of Search 72/267, 273, 272, 263, 72/257 [56] References Cited UNITED STATES PATENTS 3.431.765 3/1969 Lombard 4. 72/263 X Primary E.\&#39;mninerC. W. Lanham Assistant Examiner-Robert M. Rogers Attorney Agem. or FirmHolman &amp; Stern 57 ABSTRACT In hydraulic presses for producing closed-bottomed articles by the back-flow extrusion process, there are problems in precisely predetermining the thickness of the bottom of the article. We have a front end portion of the ram of U-shape as seen looking at right angles to the press axis and defining two stop members which project forward at the forward end of the ram, the workpiece holder having adjustable abutmcnts for the stop members. For billet loading and pressed article removal. means are provided for feeding billets to the press axis generally at right angles to the press axis. removing pressed articles from the press axis generally at right angles to the press axis and. between the ram and the billet container. for receiving billets fed by the billet feed means 15 Claims, 5 Drawing Figures PRESS FOR PRODUCING CLOSED-BOTTOMED ARTICLES BACKGROUND OF THE INVENTION The invention relates to a press. particularly a hydraulic press. for producing closed-bottomed articles. more particularly aluminium shells for gas cylinders. for instance by the backward flow extrusion process. which is normally carried out cold. Such presses usually comprise a press bed. a platen mounted on the press bed. a counterplaten spaced from the platen and also mounted on the press bed, press columns connecting the counterplaten to the platen. a ram. an extrusion punch mounted on the ram. a main hydraulic pistoncylinder unit for powering the ram during the pressing operation, at least one double-acting piston-cylinder unit for bringing the extrusion punch up to the pressing position and withdrawing the extrusion punch after pressing. a billet container for receiving the billet and holding the billet while it is extruded by the entry of the extrusion punch into the billet container. an end piece closing the rear end of the billet container. a billet container holder holding the billet container on the counterplaten. the counterplaten, the container holder. billet container and end piece acting as a workpiece holder, and a stripping device for stripping the pressed article off the extrusion punch after pressing.  
  In the cold back flow extrusion process, low extrusion forces can be used to produce. for instance, aluminium shells for gas cylinders, and in one press, the press ram is driven by a crank shaft and the stroke of the extrusion punch is defined by respective dead centres of the crank shaft. The thickness of the base or bottom of the pressed article is determined by the length of stroke of the extrusion punch.  
  A hydraulic press is also known for producing closedbottom articles by the back flow extrusion process. provided the appropriate extrusion tools were used in the press; it was customary to limit the forward stroke of the extrusion punch. and hence to determine the thickness of the base or bottom of the article. by means of a limit switch. which was somewhat imprecise. Otherwise. the prior practice was satisfactory provided the workpiece weights were low enough to enable the press to be loaded and unloaded manually, but present demands for heavier and larger workpieces make such manual loading and unloading difficult or impossible.  
 SUMMARY OF THE INVENTION According to the present invention, at least two stop members are provided for limiting the forward stroke of the ram. the stop members extending generally parallel to the press axis and being spaced from one another in directions transverse of the press axis and being disposed about the press axis. Means are provided for adjusting the forward limit of the ram stroke. and billet feed and pressed article removal means are provided for feeding billets to the press axis and removing pressed articles from the press axis in directions generally at right angles to the press axis.  
  The use of the stop members enables the thickness of the base or bottom of the article to be precisely determined, and to be adjusted using the adjusting means. In addition. the spacing apart of the stop members enables billets to be fed to the press axis in a direction generally at right angles to the press axis, and can be in a stand-by position close to the press axis when the press ram is still forward; likewise. the finished articles can be removed from the press axis in a direction generally at right angles to the press axis, and the respective removing means can be in a stand-by position close to the press axis when the press ram is still in its forward posi&#39; tion. Furthermore. the spacing between the stop members permits good visibility of the pressing operation. In addition. a billet loading means can be provided between the ram and the work holder, for receiving billets fed to the press axis, and can remain nearly in position during the pressing operation; the billet loading means can be provided with means for loading the billets precisely into the billet container and for adjusting the po sition ofthe billet loading means; this is particularly important when resetting the press for different billet diameters.  
  Billet fead means, pressed article removal means, and billet loading means can be provided for rapid. mechanical loading and unloading of the press, enabling heavier and larger workpieces to be handled.  
  The container holder can be fixed to the counterplaten and include locating means comprising at least three slots on the respective end face. extending radially to the press axis. and registering, facing slots on the container holder. with keys each engaging in two respective registering slots. In this manner. precise central guidance of the container holder can be achieved. and additional moving elements and sliding guides. which can become faulty due to wear. can be avoided.  
  Preferably. the abutments for the stop members are on that end face ofthe container holder which faces the ram. In this manner. the stop members are operational even when the billet container is removed. providing safety against the destruction of the machine parts if the press is operated without the container in position.  
  By having the stop members generally U-shaped. and particularly if one stop member is above the press axis and the other is below the press axis, billet loading and pressed article removal can be made particularly convenient. Billet loading means and article removal means can pass into the press from the side without being obstructed by the ram. and can also be in a standby position close to the press axis. saving time during the operation cycle.  
  By having the abutments for the stop members axially adjustable. particularly when the stop members are on the ram, one can provide a fixed adjusting system. i.e.. one that does not move with the ram. To ensure that the adjustment is carrier out precisely the same for both or all the stop members. a single actuating means may be provided for adjusting the adjusting means simultaneously.  
  In general. the billet loading means may act as part of the workpiece removal means.  
  If the press is a horizontal extrusion press. the removal means may comprise a pivoted dish for pivoting movement about an axis parallel to. but spaced to one side of, the press axis. from a receiving position below the press axis to an article removal position. If the press also comprises means. such as an adjustable hydraulic piston-cylinder unit for lowering the pivoted dish below its receiving position. one can avoid the outer wall of the shell which emerges from the billet container touching the surface of the dish. so that the shell can emerge freely. Physical contact between the emerging shell and the dish would cause one side of the shell to adhere strongly to the extrusion punch, and the shell could only be stripped off with difficulty; moreover. due to the irregular back flow over the extrusion punch if the shell comes into contact with the dish during extrusion, it would not normally be possible to use the shell.  
  The billet loading means is preferably mounted on that end face of the work holder which faces the ram. i.e. not directly on the press bed. and preferably again is mounted on that end face of the billet container which faces the ram. Mounting the billet loading means directly on the billet container improves the accurate positioning of the billet loading means with respect to the billet container. particularly where the height of the billet loading means is adjustable. Precise positioning is normally essential to avoid destruction of the lubricating film which is applied to the billet before the billet is charged into the container.  
 BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the invention is described, by way of example. with reference to the accompanying drawings. in which:  
  FIG. 1 is a plan view of a horizontal hydraulic press for the production of aluminium shells for gas cylinders&#39;.  
  FIG. 2 is a longitudinal section through the press, along the line II-II of FIG. 1;  
  FIG. 3 is a longitudinal section through the press, on an enlarged scale, showing the final extrusion position;  
  FIG. 4 is a cross-section along the line lVlV of FIG. 3, on an enlarged scale; and  
  FIGS is a cross-section along the line V-V of FIG. I. on an enlarged scale.  
 DESCRIPTION OF PREFERRED EMBODIMENT A base frame 1 (FIG. 2) of a horizontal hydraulic press is located in a foundation pit 2. A press ram mounting means in the form of a platen or crown 3 and workpiece holding means in the form of a counterplaten or bed 4 are disposed on the base frame 1 and are connected together by columns 5 and nuts 6. A main plunger or piston 8 slides in a cylinder 7 in the platen 3. The end face of the piston 8 is connected to a ram 9 which is guided on guideways 11 by means of flat guides 10. The ram 9 is connected to double-acting piston-cylinder 9a in the platen 3.  
  An extrusion punch 12 is disposed in a known manner on the ram 9. The top and bottom zones of the end face of the ram 9 are each provided with a thrust or stop member 13, each of the thrust members extending towards the counterplaten 4 and parallel to the press axis, giving the ram a U-shaped appearance when seen from the side. This U-shape is part of a single steel casting. The bottom thrust member 13 is laterally guided by the guideways 11 (see FIG. 4).  
  A billet container holder 14 is mounted by means of screw fixings 15 on the side of the counterplaten 4 which faces the ram 9, both the counterplaten 4 and the container holder 14 having slots in a cruciform configuration with keys 16 in the slots and extending between the counterplaten 4 and the container holder 14 to provide precise centering for the container holder 14, even when the counterplaten 4 and the container holder 14 are at different or varying temperatures.  
  Axially adjustable fixed stops or abutments 17 are disposed on the end face of the billet container holder 14, at the height of the respective thrust members 13,  
 and can be adjusted together parallel to the press axis by means of a handwheel l8 and a coupling spindle 19 (see FIG. 5). Adjustment is obtained by means of adjusting spindles 19a which slide wedge pieces 19b (see FIG. 3) over corresponding inclined surfaces forming the bases of U-section guides [90 mounted on the container holder 14, which inclined surfaces could alternatively be provided on the abutments 17; the spindles 19a are connected to the coupling spindle 19 by bevel gearing (not shown). The bottom thickness of an extruded article 20 can thus be accurately adjusted.  
  The container holder 14 contains a billet container 21. The rear opening of the billet container 21 is closed by a bottom or end piece 22 which is mounted on the rear end face of the billet container 21 by means of a mounting ring 220 secured to the billet container 21 by screw fixings. The bottom piece 22 bears on the counterplaten 4 via thrust pieces 23 and 24 (see FIGS. 2 and 3). The counterplaten 4, container holder 14, billet container 21 and bottom piece 22 act as a workpiece holder or workpiece holding means.  
  A double-acting hydraulic piston-cylinder unit 25 (see FIGS. 2 and 3) is mounted on the counterplaten 4 in order to move the billet container 21 and the bottom piece 22 into and out of the container holder 14, and acts in the direction of the longitudinal press axis. As shown in FIG. 3, a connecting rod 250 of the unit 25 carries a rotary screw threaded end piece 25!; by means of a coupling 25:, which end piece 25b is screwed into the base of the bottom piece 22.  
  A take-up and guide member 28 is provided on the base frame 1 and is pivotable about a pin 27 on a crossmember 26, from a horizontal position to a vertical position which is beneath the billet container 21 (see FIGS. 3 and 4), before the billet container 21 is retracted from its holder 14. The take-up and guide member 28 is mounted on one arm of a three-armed lever 29 whose opposite arm carries a counterweight 30 and whose third arm has a locking bore 290. The lever 29 can be locked by locking means 31 on the base frame 1 when the take-up and guide member 28 is in the horizontal position and when it is in the vertical position.  
  A pivoted loading and unloading dish 32 is mounted on one arm of a two-armed bell-crank lever 33 which is pivotable about a pin 34. The pin 34 itself is disposed in a casing 35 which is mounted by means of screw fixings 36 on that end face of the billet container 21 which faces the ram 9 (see FIGS. 4 and 5). The free end of the lever 33 carries a roller 37.  
  A ram 38 of a workpiece delivery device 39 which is disposed outside the press can be moved against the roller 37, the top of the delivery device 39 carrying a delivery dish 40 (see FIGS. 4 and 5). The pin 34 is provided with a torsion spring 41 which returns the loading and unloading dish 32 into a loading and unloading position below the press axis (shown in full lines in FIG. 5). On moving against the roller 37, the ram 38 pivots the loading and unloading dish 32 together with the extruded article 20, against the thrust of the torsion spring 41, to the discharge dish 40 (the positions being shown in dash-dot lines in FIG. 5), and the article 20 then rolls into the discharge dish 40.  
  The loading and unloading dish 32 can be swung down from the billet loading position by means of a hydraulic jack cylinder 42 (see FIGS. 3 and 5). The stroke of the loading and unloading dish 32 is adjustable by an adjustable length-of-stroke limiting device 43 in the casing 35.  
  A billet feed device 44 is disposed on the base frame 1 and can be pivoted into the press about a pin 45 by means of a hydraulic piston-cylinder unit 46 (see FIGS. 4 and 5). The top of the billet feed device 44 carries a feeder dish 47 which is additionally pivotable via a twoarmed lever 48 and a hydraulic piston-cylinder unit 49. A billet 50 which is to be processed is tilted off into the loading and unloading dish 32 when the dish 32 is in the position shown in FIG. 5.  
 OPERATION OF PREFERRED EMBODIMENT When the ram 9 is in the position shown in FIG. 2, the extruded article is removed. and the operation cycle begins. A billet 50 is supplied to the feeder dish 47 when the billet feed device 44 is in the position shown in FIG. 4. The piston-cylinder unit 46 is actuated to swing the feeder dish 47 into the position shown in full lines in FIG. 5, and it should be noted that the feeder dish 47 can. and normally will. be in this position before withdrawal of the ram 9 at the end of the preceding cycle. The piston-cylinder unit 49 is then actuated to pivot the feeder dish 47 into the position shown in dot-dash lines in FIG. 5, when the billet 50 rolls onto the loading and unloading dish 32. The billet feed device 44 is now swung back into the position shown in FIG. 4, though it should be noted that the billet feed device 44 can remain in its position shown in FIG. 5 during the forward movement of the ram 9.  
  The double-acting piston-cylinder units 90 are now actuated in order to bring the ram 9 forwards and thrust the billet 50 into the container holder 21 by means of the extrusion punch 12. When the billet 50 is in the container holder 21, the loading and unloading dish 32 is lowered and the main cylinder 7 is pressurised in order to thrust the extrusion punch 12 into the container holder 21 and extrude the billet 50 back over the outside of the extrusion punch I2. The ram 9 continues to move forwards until it is arrested by the abutment of the thrust members 13 on the abutments I7, the press thus reaching the position shown&#39;in FIG. 3 where the thickness of the base of the pressed article 20 is determined by the precise axial positioning of the abutments I7.  
  The loading and unloading dish 32 is raised and the ram 9 is withdrawn by means of the piston-cylinder units 9a. When the open end of the article 20 reaches the cross-member 52 of the stripping device 51, the stripping device 51 is withdrawn with the ram 9 until such time as its cross-member 53 arrests its further movement and the article 20 is stripped off the extrusion punch 12 and rests on the loading and unloading dish 32 in the position shown in FIG. 2.  
  The workpiece delivery device 39, which can already be, and normally will be. in the position shown in full lines, is now actuated by the extension of the ram 38,  
 and the ram 38 causes the loading and unloading dish 32 to tilt into the position shown in dot-dash lines in FIG. 5 and to roll the article 20 off onto the discharge dish 40, which will also be in the position shown in dotdash lines in FIG. 5. The ram 38 is withdrawn in order to withdraw the discharge dish 40 to the position shown in FIG. 4, and the article 20 can be removed from the discharge dish 40 in any suitable manner. It will be noted that the new cycle can commence as soon as the discharge dish 40 has reached the position shown in full lines in FIG. 5. The cycle is terminated by the return of the stripping device 51 into its forward position (shown in FIG. 3) by means of the piston-cylinder units 55.  
  The take-up and guide member 28 is normally in its horizontal position. being swung up into its vertical position for replacing the billet container 21 with another billet container. The piston-cylinder unit 25 is actuated to push the billet container 2I and the bottom piece 22 out onto the member 28. The end piece 25b is unscrewed and the container 21 and bottom piece 22 are removed and a new container 21 and bottom piece 22 replaced on the member 28 in any suitable way. The end piece 25b is screwed into the new cnd piece 22 and the new container 21 and bottom piece 22 are drawn into the container holder 14 by the piston-cylinder unit 25. The member 28 is then swung down again.  
 We claim:  
  1. A hydraulic press for producing closed-bottomed articles by the back-flow extrusion process. the press comprising:  
 press bed means;  
 press ram mounting means mounted on said press bed means;  
 workpiece holding means spaced along the press axis from said press ram mounting means and mounted on said press bed means;  
 press column means connecting said press ram means to said workpiece holding means;  
 movable press ram means mounted by said press ram mounting means;  
 extrusion punch means mounted on said press ram means, for movement along said press axis and back-flow extrusion of said articles;  
 main hydraulic piston-cylinder means mounted by said press ram mounting means, for actuating said press ram;  
 double-acting piston-cylinder means mounted by said press ram mounting means, for bringing said extrusion punch means up to a pressing position and withdrawing said extrusion punch means after pressing;  
 billet container holder means mounted by said workpiece holding means;  
 billet container means held by said billet container holding means, for receiving a billet to be pressed and holding said billet while it is extruded by entry of said extrusion punch means into said billet container means;  
 end piece means closing a rear end of said billet container means;  
 two stop members mounted on said ram means and projecting forwardat the forward end portion of said ram means, said stop members being disposed on either. side of said press axis whereby the forward end of said ram means is generally U-shaped as seen looking at right angles to said press axis;  
 abutment means fixed with respect to said workpiece holding means for abutment by said stop members at the end of the forward stroke of said press ram means. thereby limiting said forward stroke;  
 adjusting means for adjusting the axial position of said abutment means. thereby adjusting the end position of said forward stroke.  
 billet loading means mounted on said billet container means and between said billet container means and said ram means and spaced from said press axis. for supporting a said billet prior to insertion of said billet into said billet container means;  
 billet feeding means for feeding billets to said billet loading means in a direction generally at right angles to said press axis;  
 stripping means for stripping a pressed article from said extrusion punch means after pressing; and removal means for removing a said pressed article from said press axis generally at right angles to said press axis. after extraction of said pressed article from said billet container means and stripping said pressed article off said extrusion punch means.  
  2. The press of claim 1. wherein said workpiece holding means has at least three slots defined on that end face thereof which faces said ram means. which slots. as seen looking along said press axis. are radial to said press axis. said container holder means having registering. facing slots. and keys being provided each engaging in two respective registering said slots.  
  3. The press ofclaim I, wherein said abutment means are on that end face of said container holder means which faces said ram means.  
  4. The press of claim 1. wherein one said stop member is above said press axis and the other said said stop member is below said press axis.  
  5. The press of claim I. wherein said adjusting means comprises movable wedge means associated with said abutment means. cooperating fixed wedge means. means for moving said movable wedge means transversely to said press axis. thereby to adjust said axial position of said abutment means. gear means interconnecting said moving means and a single actuating means connected to said gear means. whereby adjustment of said single actuating means adjusts said adjusting means simultaneously.  
  6. The press of claim l, wherein said billet loading means acts as part of said removal means.  
  7. The press of claim 1. and being a horizontal press, wherein said removal means comprises a pivoted dish and means mounting said pivoted dish for pivoting movement about an axis parallel to, but spaced to one side of. said press axis. from a receiving position below said press axis to an article removal position.  
  8. The press of claim 7, wherein said pivoted dish mounting means comprises a two-armed lever said pivoted dish being mounted on one arm of said lever. the other arm of said lever carrying an abutment. and wherein said removal means comprises an actuating member for abutting said abutment to move said pivoted dish from said receiving position to said article removal position.  
  9. The press of claim 7, wherein when said pivoted dish is in said article removal position, said pressed article will roll off the pivoted dish. and when said removal means comprises a movable discharge dish for receiving said pressed article as it rolls off said pivoted dish. and means for moving said discharge dish in a direction generally at right angles to said press axis for transporting said pressed article out of said press.  
  to. The press of claim 9. wherein said removal means comprises an actuating member fixed with respect to said discharge dish. for pivoting said pivoted dish when said discharge dish is moved towards said press axis and into the position of said discharge dish in which said discharge dish receives said pressed article. said discharge dish being above said actuating member.  
  II. The press of claim &#39;7, and comprising means for lowering said pivoted dish below said receiving position.  
  l2. The press of claim 11, wherein said lowering means comprises a hydraulic piston-cylinder unit com prising piston means and cylinder means and adjustable means for limiting the length of stroke of said unit. and thereby defining the height of said receiving position. said adjustable means being provided between said pivoted dish and said cylinder means of said unitt R3. The press of claim I. wherein said billet loading means is mounted on that end face of said billet container means which faces said ram means.  
  [4. The press of claim 1. and comprising billet container push-out and pull-in means mounted on said workpiece holding means for acting along said press axis for pushing a first said billet container means out of said container holder means and towards said ram means and for pulling a second said billet container means into said container holder means. and billet container support and guide means which is movable into a billet container means receiving position adjacent said lower part of said container holder means. for supporting and guiding the removal of said first billet container means from said container holder means and the insertion of said second billet container means into said container holder means.  
  15. The press of claim 14, and being a horizontal press. wherein said push-out and pull-in means comprises a double-acting hydraulic piston-cylinder unit. and said support and guide means is pivoted on said press bed means. for swinging up into said billet container means receiving position.  
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