Removing shell and press residue from a metal-extruding ram disk or die

Pressing residue and shell are stripped from a metal-extruder disk having a pair of parallel and flat end faces at least one of which carries pressing residue or shell and an annular outer periphery extending between the end faces and carrying shell. First the disk and a blade are relatively displaced such that the blade sweeps across one of the faces and scrapes any press residue or shell therefrom. Then the disk is rotated about an axis perpendicular to the end faces while a plurality of angularly offset rollers are pressed radially against the shell carried on the outer periphery while the disk is rotating to radially deform the shell and separate it from the outer periphery. The shell separated from the outer periphery is then transported away from the disk.

FIELD OF THE INVENTION
 For shell-type extrusion of metals the ram disk or die ends up after an
 extrusion operation with residue on one end of the ram disk or die and
 with a shell connected to the residue and partly or wholly covering the
 ram disk or die according to the type of operation and the tool type, the
 shell collecting in an annular chamber on the outer edge of the ram disk
 or die or being compacted in a separate working step on the rear face of
 the ram disk or die opposite the residue. In order to reuse the ram disk
 or die the residue and shell must be removed.
 BACKGROUND OF THE INVENTION
 The removal of the pressing residue and if necessary of the shell compacted
 behind the ram disk or die is done by a blade run along the rear face of
 the ram disk or die and if necessary a second blade run along the opposite
 face carrying the compacted shell. The first blade forms together with the
 second blade or with a guide plate a frame in which the blade(s) and the
 guide plate have a spacing corresponding to an axial dimension of the ram
 disk or die and through which the ram disk or die is moved parallel to its
 end faces so that in this manner the residues (pressing residue and
 compacted shell) or the pressing residue on one end face are sheared off.
 The shell portion surrounding the periphery of the ram disk or die or the
 shell crumpled into the annular chamber is cut by one or two groove blades
 mounted laterally in the frame of the press-residue separator so that the
 shell is scraped out by the groove blades and is pushed off the ram disk
 or die (DE 2,506,447 and DE 2,613,241).
 Instead of fixed groove blades according to European 0,224,115 pivotally
 mounted groove blades are known which are advanced into the ram disk or
 die to scrape along its periphery and separate the shell.
 OBJECTS OF THE INVENTION
 It is an object of the invention to remove the shell from the ram disk or
 die more surely.
 SUMMARY OF THE INVENTION
 This object is attained by radially spreading the shell to be removed by
 roller pressure while rotating the ram disk or die whose end faces have
 been freed of residue (pressing residue and compacted shell) and rotating
 the roller or rollers braced radially against it and subsequently axially
 stripping the sufficiently spread shell.
 The apparatus for carrying out the method is a frame formed of two blades
 or one blade and a guide plate at a spacing equal to the axial dimension
 of the ram disk or die, a press-residue remover comprised of a slide
 moving the ram disk or die parallel to the blade or blade according to a
 further feature of the invention, a spreading device provided with
 rotatably driven rollers radially displaceable against the ram disk or die
 and forming a central rotatable holder for the ram disk or die and for
 separate removal of the ram disk or die and the shell.
 A preferred embodiment of the spreading device has three movable rollers.
 It is preferable here that the holder for a ram disk or die and the roller
 or rollers are arranged in a horizontal plane with vertical rotation axes.

SPECIFIC DESCRIPTION
 The apparatus for removing the residue and shell from a ram disk or die
 used with shell-type metal extrusion has basically two parts, namely a
 shear 1 in which the residue on the one end face of the ram disk or die
 and if necessary the shell crumpled on the other end face is sheared off
 and a stripper 2 in which the shell which surrounds the ram disk or die is
 removed.
 The shear 1 is formed as described in German 2,505,160 or European
 0,224,115 and comprises a support table 3 on which is held the residue-
 and shell-carrying ram disk or die 4 fed in by an appropriate transport
 system from the extrusion press. Next to the support table 3 on one side
 is a slide pusher 6 movable by a piston-cylinder unit 5 and aligned on the
 opposite side is a frame 7 carrying a lower blade 8 and an upper blade 9.
 Appropriate actuation of the piston-cylinder unit 5 advances the slide 6
 to the frame 7 and into same thereby sliding the residue- and
 shell-carrying ram disk or die 4 onto the system axis of the stripper 2
 (position 4'). As the ram disk or die 4 enters the frame 7 the lower blade
 8 shears off the residue on the lower face of the die 4 and, if the
 opposite end face is carrying a crumpled shell, the upper blade 9 shears
 off the crumpled shell from the upper end face of the ram disk or die 4 so
 that it is only left with shell wrapped around itself which can be removed
 in the stripper 2. The residue and shell left on the support table 5 is
 dropped into a scrap bucket 10, to which end the pivotally mounted support
 table 3 is swung down by a piston-cylinder unit 11.
 The stripper 2 acting as a spreading device is in the illustrated
 embodiment provided as shown in FIGS. 3 and 4 with three rollers 12 that
 are rotatably mounted in slides 13 and movable therewith by
 piston-cylinder units 14 radially to the system axis. At least one (here
 two) of the rollers 12 are driven by a respective hydraulic motor 27. The
 frame 15 carrying the rollers 12 with their slides 13 is formed by an
 upper plate 16 and a lower plate 17 and roller guides 18 formed along with
 slide guides 19 and chamber walls 20 as spacers therebetween.
 A brace plate 21 can be moved in from below along the system axis and has
 an unillustrated turntable. The plate 21 is raised and lowered by a
 piston-cylinder unit 22 that is protected by a sleeve 23 which is in turn
 connected with the brace plate 21 and telescopes with an inner shield
 sleeve 24. The brace plate 21 is formed with lateral flats so it can be
 dropped through a fork-like stripper plate 25 and a ram disk or die 4 can
 be stripped of shell as it is dropped and moves into a trough 26 for
 transport back to the extrusion press.
 Angularly centered between the rollers 12 are push rods 29 guided in
 cylinders 28 and each carrying a scraper plate 30 whose shape mainly is
 determined by the ram disk or die and two adjacent rollers 12. Each
 scraper plate 30 is provided with two guide rods 31 that slide in bores 32
 of the upper plate 16 and in the mounting flanges of the respective
 cylinder 28.
 The upper plate 16 is shown in detail in FIG. 5 and the lower plate 17 in
 FIG. 6. Without showing the threaded holes for connection of the roller
 guides 18, the slide guides 19, and the chamber walls 20 with the upper
 plate 16 and lower plate 17, FIG. 5 shows a top view of the upper plate 16
 with a central opening 37 through which the ram disk or die can be raised.
 Further shown are the bores 38 for the push rods 29 and the bores 32 for
 guiding the guide pins 31 as well as slots 39 for the motors 27 extending
 through the upper plate 16. FIG. 6 shows the lower plate 17 with its
 star-shaped opening 40 that includes a central aperture through which the
 brace plate 21 with the ram disk or die 4 passes and the openings 34 and
 35 for removal of the shell scrap.
 After a ram disk or die 4 is as described above advanced by the push slide
 6 of the piston-cylinder unit 5 through the frame 7 with the lower blade 8
 and the upper blade 9, further advance of the slide 6 puts the ram disk or
 die in the position 4' centered on the system axis of the stripper 2. To
 this end two of the rollers 12 are moved laterally out of the path of the
 ram disk or die 4 to a spacing equal at least to the diameter of the
 shell-covered ram disk or die 4. The slide guides 19 serve to laterally
 guide and bars 33 on the slide guides 19 and, on the last part of the
 path, the brace plate 21 in its upper position serve to support the ram
 disk or die 4.
 As soon as the ram disk or die reaches the position 4' the three rollers
 are concentrically moved in and pressed against the ram disk or die 4 and
 then set to rotating. This roller action exerted on the shell serves to
 spread the shell that bulges out between the roller zones and separates
 from the periphery of the ram disk or die 4. The continuous rolling and
 bending action on the shell normally leads to rapid fracture of the shell
 and the pieces fall through one of the openings 34 below the chambers
 defined by the chamber walls 20 or through opening 35 between the guide
 bars 33 into a scrap bucket 36. If the shell material is very ductile so
 that the shell does not fracture, the stripping of the spread shell is
 effected by the scraper plates 30 moved by the push rods 29 and engaged
 with their edges between the rollers on respective peripheral sections of
 the ram disk or die 4 so as to comminute the shell. After removal of the
 shell or its pieces the ram disk or die 4 freed of residue and shell is
 sent back to the extruder by sinking of the brace plate 21.
 Instead of proceeding as in the illustrated embodiment by sinking the brace
 plate 21 to send back the ram disk or die 4 freed of residue and shell,
 with appropriate construction of the bracing device this can be raised and
 it can be taken away from above the stripper 2 to the extrusion press
 which has the advantage that the removal of scrap and the taking-away of
 the ram disks or dies are separated.
 Fracturing of the spread shell by rolling can be improved when the rollers
 are provided with cutting edges with grooves transverse to the rolling
 direction that cut into the shell, which requires stopping the rollers at
 a predetermined end position in order to avoid damage (grooving) of the
 ram disk or die. With ram disks or dies that are combined with a
 shell-stripping disk and where the shell can collect in an annular chamber
 ahead of the shell-stripping disk, it is recommended that the rollers have
 a ridge engaging in the annular chamber of the ram disk or die in order to
 groove the shell, the ridge diameter plus the cutting depth not exceeding
 the basic diameter of the roller more than the depth of the annular
 chamber so that when the roller contacts the ram disk or die the cutting
 edges do not reach the floor of the annular chamber. In this case however
 the cutting depth can be less than the shell thickness so that spreading
 of the shell by rolling is sufficient.