US2925176A

US2925176A - Dummy head or block for end of extrusion ram

Info

Publication number: US2925176A
Application number: US609969A
Authority: US
Inventors: Wyngaert William Arthur
Original assignee: Kaiser Aluminum and Chemical Corp
Current assignee: Kaiser Aluminum and Chemical Corp
Priority date: 1956-09-14
Filing date: 1956-09-14
Publication date: 1960-02-16
Anticipated expiration: 1977-02-16

Description

2 Sheets-Sheet l w. A. WYNGAERT DUMMY HEAD 0R BLOCK FOR END OF EXTRUSION RAM INVENTOR ATTORNEY l ulll WILLIAM ARTHUR WYNGAERT Feb. 16, 1960 Fired Sept. 14, 1956 hhv k DUMIVIY HEAD OR BLOCK FOR END OF EXTRUSION RAM Application September 14, 1956, Serial No. 609,969

4 Claims. (Cl. 207-9) This invention relates generally to improvements in extrusion presses. More specifically, it relates to an improved attachment for the ram of an extrusion press for facilitating the breaking of contact between the ram and the remainder of the metal billet at the completion of the, extrusion.

In extruding of metals, such as aluminum and aluminum alloys, a cast billet, usually cylindrical in shape, is heated to the desired extruding temperature and positioned in a press, comprising generally an extrusion cylinder or container, a ram which is fitted with a dummy block somewhat smaller than the cylinder diameter, and a die having an opening conforming to the cross-sectional configuration of the desired extrusion. As the billet is forced against the die by the ram, the metal of the billet is caused :to flow or extrude through the die opening. During the extrusion cycle, the dummy block adheres to the butt of the billet thereby necessitating the application of a force or impact to separate the dummy block from the butt of the billet. In the case of unattached dummy blocks, that is, where the dummy block is not fixedly joined to the extrusion ram, the dummy block and the billet butt can be separated by disassembling the die holding mechanism, after firstshearing the extrusion from the butt by a suitable means. After the die and die holding mechanism are removed from the extrusion cylinder the butt of the billet with the adhering dummy block can be easily removed and the dummy block can be separated from the butt manually, such as by a hammer blow.

Dummy blocks which are fixedly attached to the extrusion ram are being increasingly used because of the advantages they have over the unattached dummy blocks. With fixedly attached dummy blocks continuous extrusions, that is, single extrusions formed from a plurality of billets, can be made. However, in the case where the dummy block is fixedly attached to the extrusion ram, difiiculty is experienced in separating the dummy block from the butt of the billet. On the return stroke of the ram the butt is also pulled back. This will cause the extrusion to be pulled back through the die openings causing considerable scrap metal with the attendant loss of production. Normal lubricants have been tried to prevent. this sticking or adhering of the dummy block to the butt of the ingot but no measure of success has been attained.

Therefore, it is a primary object of this invention to i provide a novel dummy block which is fixedly attached to an extrusion ram and an arrangement for easily breaking the adherence of the dummy block to the butt of the billet.

It is also an object of this invention to provide a novel dummy block fixedly attached to the extrusion ram Wheret in said dummy block is comprised of several members in locked and sliding relationship thereby allowing the adherence of the dummy block to the butt of the ingot to be broken in multiple steps.

It is a further object of this invention to provide means States atent ICC for the passage of air into the zone where the dummy block contacts the butt of the ingot in order to aid in the breaking of the adherence of the dummy block to the butt of the ingot.

These and other objects of the invention will be apparent from the ensuing detailed description when taken in conjunction with the drawings.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same:

Figure 1 shows a plan view of the dummy block embodying the instant invention,

Figure 2 is a view similar to Figure 1 except that the dummy block is shown partly in section to more clearly show the relationship of the component parts,

. Figure 3 is a sectional view of the dummy block taken along the line 33 of Figure 1,

Figure 4 is a sectional view of the dummy block taken along the line 4-4 of Figure 1,

Figure 5 is a sectional view of the dummy block taken along the line 5-5 of Figure 1.

Referring to Figures 1 and 2, the dummy assembly embodying the instant invention is denoted as 1 and comprises in general a central ram member 2, an outer shell member 3, and an outer shell nut 4-. During the extrusion of a metal billet lit), the concave face assembly 20 of the dummy block assembly engages the butt of the billet 30, and movement of the dummy block assembly 1 derived from a suitable source of power, such as a hydraulic ram, causes the billet 30 to be extruded through the die (not shown) of the extrusion press. Concave face assembly 20 comprises the concave face 22 of central ram member 2 and concave front surface 21 of outer shell member 3.

As shown in Figures 1 through 5, the central ram member 2 of the dummy block assembly 1 comprises a nose portion 14 having a raised central portion 16 provided with a diameter greater than that of the nose portion 14, and a rear portion 34 having a stud 23 which is fixedly attached to the piston or rod 27 of a hydraulic ram by suitable means such as threads 24. Channels 10 and 11 extend circumferentially around the surface of raised portion 16 and channels 33 extend longitudinally on the surface or face of portion 16 and intersect channels 10 and 11. Channel 31 extends circumferentially around the surface of nose portion 14 of central ram member 2. Channels 28 which extend longitudinally along the surface of nose portion 14 intersect channel Y 31'. Channels 35 which are disposed radially on the surface of the abutment 15 of outer shell member 3 lend a passageway between channels 33'and channel 31 when central ram member 2 and outer shell member 3 are in operating position, thereby providing a passage between the channels 33 on the raised portion 16 and the channels 28 on the nose portion 14 of central ram member 2. The channels ltl, 11, 33, 35", 28 and 31 allow air to be admitted into the dummy block assembly 1 for the purpose of aiding in the retracting of the dummy block assembly 1 from the butt of the billet 30, as will be discussed hereinbelow. In addition to being air passages, channels It), 11, 33, 35, 28 and 31 also serve as passages for lubricants. Nose portion 14 of the central ram 2 has a taper 32 at its forward extremity and a face 22, as shown in Figures 1 and 2, dished concavely matching the concavity of the front surface 21 of the outer shell member 3. Although a concave surface on the face of a dummy block appears to aid in the retraction of the dummy block, it is not to be construed that the instant invention is limited to this configuration. The invention, in addition to the concave face as shown, also includes dummy block assemblies having flat front faces and also convex faces.

Outer shell member 3, as shown in Figures 1, 2, 4 and 5, is of ring-like structure, and is in concentric relationship with central ram member 2 in the dummy block assembly 1. As shown in Figures 1 and 2, the tapered portion :13 ofou ter shell member 8 engages in 'a close fit the taper 32 of the nose portion 14 of the central ram member 2. An abutment 15, which extends circumferentially around the inner surface of outer shell member 3, engages the front surface or abutment 17 of the raised portion 16 of central ram 2. The abutment 15 should be placed so that, when it engages surface 17 during the forward-stroke of the hydraulic ram, .the force transmitted from the central ram member 2 to the outer shell member 3 is primarily directed through the abutment 15 rather than through the tapered portion 13 of the outer shell .3 which acts as a seat for taper '32 of central ram 2. The abutment15 should, however, be designed so that a substantially close engagement between tapered portion 13 and taper 3210f the central ram 2 is realized during the extruding stroke of the hydraulic ram and dummy block. The land 29is a raised portion extending circumferentially around the outer surface of outer shell member 3. The land 29, which has a flat machined portion, the diameter of which is slightly less than the diameter of the extrusion container (not shown), acts as a guide for the dummy block assembly 1 during the extrusion of a billet. More than one land may be used in, a dum y ck n o g y, t e n ention i no to be construed as limited to nly one land asshown in the figures.

Holes 5 and 6, which are disposed radially around the outer shell member 3, serve as passages for air'to the

channels

10, 11, 33, 35, 28 and 31 of central ram member 2. In addition, holes 5 and 6 may also be used for introducing lubricants between the adjacent surfaces of central ram member 2 and outer shell member 3. Further, the holes 5 and 6 may be used for inserting suitable tools therein to gain leverage during the assembling and disassembling of the threaded engagement between outer shell member 3 and outer shell nuts.

Outer shell nut 4, as shown in Figures 1, 2 and 3, is also of ring-like structure and is in concentric relation ship with central ram member 2 in the dummy block assembly 1. Outer shell nut 4 has on its outer surface threads 25 which engage the threads 26 on the internal surface of the outer shell member 3, which threaded engagement joins in locked and sliding relationship outer shell member 3 and outer shell nut 4 onto central ram member 2. The front portion of nut 4 when threadedly engaged with outer shell member 3, extends inwardly a distance greater than the adjacent inner surface of the outer shell member 3, thereby forming abutment 19 as shown in Figures 1 and 2. Abutment 1 9 is engaged by the rear surface :18 of the raised portion 16 of the central ram member 2 during the retracting stroke of the hydraulic ram. As shown in Figures 1 and 2, shell nut 4 has a threaded hole 7 in which a set screw 8 can be disposed in order to ensure against unthreading between shell member 3 and shell nut 4. Also shown in Figures 1, 2 and 3 are holes 9 which are disposed in a radial manner around the shell nut' 4. The holes 9 serve a dual function, one of aiding, in conjunction with holes I block assembly 1 which is fixedly attached to piston 27 5 and 6 of outer shell member 3, in the assembly and disassembly of the dummy block assembly 1 and the other as a passage for lubricating the surfaces of central ram member 2 and shell nut 4 which are in adjacent relationship. The holes 9, as radially placed, allow the insertion of suitable tools in order that sufficient leverage can be attained to assemble and disassemble the threaded engagementbetween outer shell member 3 and shell nut 4. As shown in Figures 1, 2 and 3, the inner surface of shell nut 4 has longitudinal channels 12 which intersect holes 9 thereby providing a passage for a lubricant to be flowed in between the adjacent-surfaces of shell nut 4. and central ram mem er 2- 1n the operation of the described device the dummy of a hydraulic ram is moved into the extrusion container after a heated metal billet'30 has been placed therein. As hydraulic piston 27 proceeds with its forward movement, concave face assembly 20 of dummy block assembly 1 contacts the butt of the billet 30-, the billet 30 is pushed against the die, and the heated metal is caused to flow or extrude through the die openings. When the extrusion of the billet 30 is complete, that is, only a small butt section of the billet 30 is left in the container, the hydraulic piston 27 is retracted. During the initial part of the retraction only the central ram member 2 of the dummy block assembly 1 will move, thereby only the adherence of concave face 22 of central ram member 2 to the butt of the billet will be broken. As the hydraulic piston 27 proceeds in its rearward movement, the circumferential channels 10 and 11 on central ram member 2 will become aligned with holes 5 and 6, respectively, .of the outer shell member 3, thereby allowing atmospheric air to flow through

channels

10, 11, 33, 35, 28 and '31, thereby breaking the vacuum which forms in thespace between the butt of the billet and the concave face 22 of the central ram member 2, thereby facilitating the release of the adherence between central ram member 2 and the butt of billet 30. When the surface 18 of the raised portion 16 of central ram member 2 engages the abutment 19 of shell nut 4, the adherence between the concave surface 21 of the outer shell member 3 and the butt of the billet 30 will be broken. The dummy block assembly 1 may then be retracted completely from the container in order to allow a successive billet to be loaded therein.

It-is obviousvthat many changes or modifications may be made without departing from the spirit and scope of the invention and, accordingly,'the invention is not limited [by whathas been disclosed in the foregoing description but ,onlyby theappended claims wherein what is claimed ,1. In-an extrusion :press wherein a dummy block for engaging the buttof a metal .billet .is attached 'to an extrusion ram, the combination of a dummy block comprising a central ram member, an outer shell member and an outer shell nut, said outer shell member and said outer shell nut being threadedly joined together and being in a limited sliding concentric relationship with said central ram member, said central ram member including a nose portion having a concave extremity there of, a taper contiguous with said concave extremity, a raised portion having a diameter greater than that of said nose portion, and a rear portion having a stud threadedly engaged with said extrusion ram, said outer shell member having a concave extremity thereof, a tapered surface contiguous with said concave extremity of said outer shell member and providing a seat for-said taper on said nose portion of said central ram member, an abutment extending circumferentially around the inner surface of said outer shell member for contacting the raised portion of said central ram member, the front extremity of said shell nut when threadedly engaged with said outer shell member extending radially inward a distance greater than that of the adjacent inner surface of said outer shell member thereby providing an abutment for contacting the rear surface of said raised portion of said central ram, said central ram member and saidouter shellmem ber adapted to provide a concave face for engaging the butt of said metal billet when said taper of said nose portion is seated in the tapered surface of said outer shell member.

2. In an extrusion press wherein a dummy block is attached to an extrusion ram, the combination of a dummy block assembly comprised of a central ram member fixedly attached to the said extrusion ram, an outer shell member loosely surrounding said central ram member, means including an outer shell nut holding said outer shell member in a concentric but limited slidable relationship with respect to said central ram member, said central ram and shell members both having billet contacting faces at the forward ends thereof, abutment means of said outer shell member and a separate abutment means on said outer shell nut located in spaced relationship to said first-mentioned abutment means and on said centralon said central ram member being 'engageable with the abutment means on the outer shell nut during the re turn stroke of the ram whereby during the forward movement of the extrusion ram the outer shell member and central ram member move in unison and during the return stroke of the extrusion ram said outer shell mem. her and said central ram member move in sequence so that the adherence of the billet contacting face of the central rarri' member to the billet is broken before the adherence of the billet contacting face of the outer shell member tothe billet is broken.

3. An extrusion press as set forth in claim 2 wherein the central ram member and the outer shell member are providedwithmeans which permit the entrance of atmospheric air into said dummy block assembly adjacent the billet contacting faces of the central ram and outer shell members during the return stroke of the extrusion ram so as to break the vacuum which exists between the billetand the billet contacting face of the central ram member. I

4An extrusion press as set forth in claim 1 wherein said central ram: member is provided with intersecting circumferentially and longitudinally disposed channels 7 on a surface thereof and said outer shell member is providedwith air passage means, said channels and air passage means being so disposed that they are placed .in registry with each other during the return movement of the extrusion ram whereby atmospheric air can enter I the dummy block during the return stroke of the ex trusion rain and break the vacuum which exists between i the butt of the billet and the portion of the central ram 7 member which comprises the billet engaging face there- References Cited in the file of this patent UNITED STATES PATENTS 878,092 Schwicger Feb. 4, 1908 927,076 Remmen July 6, 1909 2,031,014 Staples Feb. 18, 1936 2,160,963 Friden June 6, 1939 2,165,711 Kreidler July 11, 1939 2,639,809 Perry et al. May 26, 1953 2,879,887 Haw-tin Mar. 31, 1959 FOREIGN PATENTS 732,603 Great Britain June 29, 1955 932,334 France v. Nov. 24, 1947