US2396108A - Metalworking press - Google Patents

Description

Marh 5, 1946. L.. I oEwY METALWORKING PRESS Filed July 9, 1941 3 Sheets-Sheet 2 l.. LoEwY METALWORKING PRESS March .'S, 1946,

Filed July 9, 1941 5 Sheets-Sheet 3 to a very considerable extent.

s PATENT N oFFlca METALWORKING PRESS Ludwig Loewy, Bournemouth, England, assigner to The Loewy Engineering Company lagging, England, a corporation of Great application v 4 Claims. This invention relatesto metal working presses and, in particular, to metal extrusion presses of the vertical type, in which rods, shapes and tubes are produced by extruding a billet placed within a container through'a die which is inserted at one end ot this container.

and serves also to define, together with the die,

an annular passage for the extruded product;

Presses are further known in which cup-shaped hollow bodies, such as cases. for ammunition shells, are produced byv piercing or punching a slug placed within a closed-bottom lmatrix and by forcing a certain portion of the slug material at the same time lziackwards through the space between the bore of the matrix and the descendl ing punch. The pierced workpiece is either ejected from the matrix after the punch is withdrawn, or, in those cases in which the workpiece' adheres to the punch, it will be stripped from the latter, special means being provided in the press for the ejecting or stripping operation.

, Heretofore, different machinery had to be used for the extrusion of metal rods, shapes and tubes on one hand and for the manufacture of cupshaped hollow bodies on the other, and it was not possible to use either a normal extrusion press or a normal piercing press for both purposes.

It is an object of this invention to provide a press which can be alternatively used for the extrusion of metal rods, shapes or tubes, and also for the manufacture of cup-shaped hollow bodies,

such as cases for ammunition shells, thus widening the range of products which can be obtained from such a pressrand increasing its usefulness Itis another object of this invention to provide a vertical extrusion press which can be transformed into a piercing press in a very simple manner, so that the change-over from one mode of operation to the other can be accomplished in a comparatively short time and with little labour.

'I'his object is achieved by suitably adapting those elements which have to bel added -to the press for the manufacture of cup-shaped hollow bodies to the specific structural features oi'a verticalextrusion press, in suchpa way that the heavier and the more complicated parts, `such as Limited,

July 9, 1941, Serial N0. 401.578 Great Britain May 9, 1941 exchange oi the respective tools and their acces--A sories.

It is, therefore, a'iurther object of this invention'to provide means for adapting temporarily a vertical extrusion press of normal design to a piercing press in which cup-shaped hollow bodies and, in particular, semi-ilnished cases for ammua nition shells can be produced. s

In carrying out the invention, the punch for l the main power drive, which in the extrusion press is provided ior the actuation of the press stem. Thus, thispunch will take the place of the press stem and can be coupled to the main ram so as to be actuated by the latter and its the place of the container.

The ejecting means of the piercing press will be coupled with the return rams, preferably through downwardly extending tie-rods and a crosshead arranged below the press, so that the ejector will enter the matrix from below when the punch is being withdrawn from the matrix.

It is another feature of the invention to utilise the second power drive for operating the stripping means, this power drive being particularly suitable for that purpose since it is capable of being moved independently of the main ram. The place of the mandrel will be taken by astripper pin, which to vbe eiective is pushed downwards, while the punch with an adhering workpiece remains stationary.

It is'to be noted here that the stripping pin when pushing oil a workpiece from the punch will only engage the bottom wall of the work# piece and not, as in the case of known piercing presses, the side walls. This is of particular importance since the side walls are comparatively thin and therefore more liable to deformation than the thicker bottom walls.

For controlling the thickness of the bottom wall of the cup-'shaped hollow bodies, a distance piece is associated with the punch which is adapted to limit the working stroke of the latter.

In a modication of the invention, the separate actuating means for the stripping means are dispensed with and a stop is provided instead which is arranged in the path of the upward stroke of the stripper pin.' This stop brings the stripper pin to rest while the punch, with an adhering workpiece, will continue its upward movement so that the stripper pin will strike against the bottom wall of the adhering workpiece and push it off in the same way as described before. In this case, the second power drive which is axrlde for the mandrel of an extrusion press will be d mantled and the parts connecting the lmandrel to this power drive. such as a mandrel shaft, will be immobilised by anchoring the same t0 the Dress fraugtflhis arrangement has the piercing the 'slugs will become associated with return rams respectively. The matrix will take ,y

`following',specification with reference to the accompanying drawings in which:

less height than the container, an intermediate backing piece 32 will ybe placed between the matrix andthe die on one side and the bolster 21 Fig. 1 is a sectional elevation of a vertical metalI I extrusion press adapted for the extrusion of rods,

shapes and tubes.

Fig. 2 is a sectional elevation of the press according to Fig. 1 adapted for the manufacture of cup-shaped hollow bodies.

Fig. 3 is a more detailed view of the tool assembly of the press according toV Fig. 2.

Fig. 4 shows a modified way of adapting a press according to Fig. 1 to the manufacture of cupshaped hollow bodies.

In the drawings, ID denotes the main or upper platen for a vertical metal extrusion press in which the various hydraulic power drives are arranged and which is supported on the baseplate I I by means of columns I2. Located in the centre of platen I is the main ram I3 which carries at its lower end a press stem I4 by means of the tool holder I 4.

Passing through an axial bore in ram I3 and press stem I4 respectively, are piercing mandrel I5 and mandrel holder I6, the latter being detachably mounted on a shalt I I which extends axially through the ramfI3 and projects beyond platen I0.

Shaft Il carries at its upper end an upper cross-head I8 with which two laterally arranged piercing rams are associated. These rams are shown in the drawings as being of the double-acting type, so that the crosshead I8, and with it the piercing apparatus consisting of the parts I5 to I1, can be lowered and raised in accordance with the movement of the rams I9.

For effecting the return movement of stem I4, rams are provided near the ends of platen IIJ, which rams are connected to main ram I3 by y" means of tie-rods 2I and a lower crosshead 22.

The rams 20 are connected with upper crosshead I8 by means of extension rods 23 so that movement of the main ram I3 will be transmitted to the piercing apparatus through. the intermediary of the lower crosshead 22, tie-rods 2|, return rams 20, extension rods 23 and upper crosshead I8. Upper crosshead I8 is capable of sliding a certain distance d" along rods 23 so as to render the piercing apparatus independently moveable from main ram I3 to some extent.

Arranged on baseplate I I is a container holder 24 which is adapted to receive a billet container 25. A die 26 is removeably inserted at the end of the container bore and supported in the contaner holder, together with the container, by means of a bolster 2l.

The metal extrusio-n press described so far is of normal design and operated in a well known manner, so that a detailed description of the operation is not considered necessary. For transforming this press into a piercing press, the fol.- lowing changes have to be made:

The container and the die 2B will be exchanged for a matrix 30 having a bore of suitable size to take up slugs-ior the manufacture of cup-shaped hollow bodies. A bottom plate 3i is loosely inserted into the end of the matrix bore so as to close the same. As matrix 30 is of at the other side. Means will be further attached to the press for electing workpicces from matrix 30, these means comprising an elector pin 33 mounted on a crosshead 34 which is connected by means of tie-rods 35 to the lower crosshead 22 and thereby also to the return rams 20. The bottom plate 3I has a finger 36 whichdepends into the opening of baseplate II provided therein for the passage ofthe extruded products.

A further'exchange to be made is that of the piercing stem I4, the mandrel. I5 and the mandrel holder I8, for a punch and stripper assembly which is shown more in detail in Fig. 3.

This assembly comprises a punch 3l fixed to the main ram by means of a tool holder 38, a distance piece 39 being attached to tool holder 38. Screwed into shaft I1 in place of mandrel holder IB is an extension 4I. loosely arranged in an axial bore of punch 3l is a stripper pin 42, this pin being normally held back by means of a extent moveable independently of the main ram and this feature is utilised for moving the stripping pin relatively to the punch 3l.

Movement is transmitted to stripper pin 42 by means of shaft Il and shaft extension 4I. As shown in Fig. 2, a small clearance 4Ia is normally maintained between the bottom end of extension 4I and the top end of stripper Din 42; furthermore, the pin 42 is flanged at its lower end and fits there snugly into a 'correspondingly shaped bore of the punch; thus it is ensured that during the piercing operation pin 42 will neither be pushed out too far by an accidental movement of shaft I1, nor trail behind the punch 3l.

It will be noted here that all the main parts of the press, such as the main ram and all other components of the various hydraulic power drives, will remain unaffected by the above modifications. Neither are alterations necessary to the frame parts, such as the platen I0 and the baseplate I I, or to the control apparatus of the power drives which are not shown here.

The work necessary for transforming the extrusion press to a piercing press is limited to an exchange of the tools and their accessories and to the incorporation of the electing and of the stripping means into the press. These modifications can be carried out in a few hours, so that the interruption in the operation of the press will be only of short duration.,

In the following, the mode of operation of a piercing press according to Fig. 2 will be shortly described:

A slug of suitable size is first placed into the matrix 30; punch 31 is then actuated by means of main ram I3 to pierce the slug and, at the same time, to force a part of the slug material backwards through the space between the matrix asesinos l for actuation o f a stripping means independently by the length of the stroke of the punch and this again is determined by means of the distance piece 39 which, at the end of the stroke, will abut against the top surface of the matrix.

After the punchhas completed its working stroke, it is withdrawn from the matrix by means of the return rams 20. At the same time, the ejector crosshead 34 is moved upwards and ejec-v tor pin 33 will strike against finger 36 whereby lthe bottom plate 36 with the pierced workpiece will be pushed out of the matrix. In those cases in which avworkpiece adheres to the punch on its withdrawal, the stripper pin 42 will be made eiective for pushing oif lthe workpiece from the punch in the manner described above by means of rams i9 and shaft I1. After the stripping has been completed, shaft i1 will'be returned into its original position and the pin 4 2 drawn back by means of spring 43,

In the modification shown in Fig. 4, the hydraulic power drive which, in the extrusion press,

was provided for the mandrel and which consisted of the double-acting rams I9, is dispensed with, and the shaft I1 is anchored to the platen I0 by means of tie--rods `44 attached to a crossbeam 45 which is mounted on shaft i1 inexchange for uppery crosshead I8.

The operation of this press is the same as that according to Fig. 2 as far as the piercing of the slugs and the ejecting of the workpiece from the matrix are concerned. The stripping of any .workpieces adhering to the punch is obtained by continuing the upward stroke of the punch while the stripper pin 42 has been arrested by abutting against the end of shaft l1, thereby pushing off the workpiece from the punch, so that no additional operation of any press parts is required for effecting the stripping.

In this case, shaft extension 4| will be shorter so as to allow the pin 42 to beretracted suillcient- 1y to clear the matrix when being withdrawn together with the punch.

It is to be understood that the invention is not limited to that particular form of an extrusion press which is shown and described here. The

i invention is equally applicable also to other designs of extrusion presses, ,for instance, to an extrusion press having a closed frame in the upper part of which are arranged the power drives, whereas the bottom part of the frame takes up the container-holding elements and their accessories.

Cup-shaped hollow bodies which are produced with presses according to the invention in the manner described here are then subjected to a further treatment consisting of a number of drawing operations until the final dimensions are obtained.` Experience has sho'wn that on a press according to the invention a product can .be obtained, the dimensions of which-are much nearer to the iinal ones than was previously possible, with a corresponding reduction in the necessary -number of drawing operations. This in itself of said first power drive, said second power drive comprising a mandrel shaft extending through said main ram, and holding and supporting means for a billet container, of a punching tool adapted tol pierce blanks,- said tool being associated with said iirst power drive for actuation thereby, a blank-receiving ma rix associated with said supporting and holding ejecting a pierced blank from said matrix, said ejecting means being coupledto said iirst power drive so as to enter said matrix on the return stroke of said punching tool, means for stripping a pierced blank from said punching tool, said stripping means being located in said punching tool and associated with said second power drive, and means for moving said mandrel shaft so as to cause said stripping means to project from said punching tool to strip a pierced blank from said punching tool.

l2. A press for making cup-shaped hollow bodies, having a double-acting power drive, an

axially bored shaping tool, actuated by said power drive, a blank receiving matrix, means for removing the shaped blanks from said matrix, said removing means being operatively connected to said power drive, a stripping pin, arranged in the axial bore of-and adapted to be lowered together with said shaping tool, and means for moving said stripping pin out of said shaping tool in a direction opposite to the return stroke of -said shaping tool, said means constituting a second double acting power drive operative separate from said first mentioned power drive. I

3. A press for making `cup-shaped hollow bodies, having two independently operated power drives of the double acting type, a hollow blank piercing tool, acrosshead, adapted to be moved in a vertical direction by the ilrst of said power drives and carrying said tool, a blank receiving matrix, meansfor removing the pierced blanks from said matrix, said removing means being op-. eratively connected to said rst power drive,

means located 'in said hollow blank piercing tool vstroke to move the stripping means out of the hollow blank piercing tool to strip the cup-shaped article therefrom.

4. A press for making cup-shaped hollow bodies comprising a support, a blank receiving matrix connected to said support, a cross-head movable on said support toward and from said matrix, a hollow punch carried by said cross-head and adapted to enter said matrix, a stripper member l movable longitudinally within the punch and having an enlarged head fitting a recess in the end of the punch, an ejector 4movable longitudi-v nally within the matrix to eject work ,therefrom, `a ram carried `by said support and opern able to move the cross-head and punch toward said matrix, a ram carried by said support opI erable to move the cross-head away from ^the matrix and to operate the elector, and a ram operable to actuate the stripper to remove a; hol-v low body from the punch.

LUDWIG DOEWY.

eans, means for i

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