US3867830A

US3867830A - Forging press

Info

Publication number: US3867830A
Application number: US382616A
Authority: US
Inventors: Heinz Dettwiler
Original assignee: Hatebur Umformmaschinen AG
Current assignee: Hatebur Umformmaschinen AG
Priority date: 1972-08-02
Filing date: 1973-07-25
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25
Also published as: FR2194502B1; DE2237913A1; CH568112A5; GB1432167A; BE802699A; AT323516B; NL7310643A; FR2194502A1; JPS4979946A; SE384152B; IT991839B; NL156942B

Abstract

This invention relates to a forging press provided with transport tongs. The forging produced by the press is provided with a flash which has areas which can readily be engaged by the transport tongs.

Description

O Umted States Patent 1 1 3,867,830 Dettwiler Feb. 25, 1975 FORGING PRESS 2,802,381 8/1957 Leasia 72/427 2,851,980 9/1958 Kraicinski 72/361 [751 Invent f" Dettwller, Lupsmgen 3,525,248 8/1970 Schulte et a1. 72/361 Switzerland 3,713,320 1/1973 Andresen 72/361 [73] Assignee: Hatebur Umformmaschinen AG,

Basel Switzerland FOREIGN PATENTS OR APPLICATIONS Filed: J y 1973 200,897 2/1956 Australia 72/344 [21] Appl' 3826l6 Primary Examiner-Richard J. Herbst Attorney, Agent, or Firm-Markva & Smith [30] Foreign Application Priority Data Aug. 2, 1972 Germany 2237913 [57] ABSTRACT 52 us. c1. 72/361, 72/427 51 1m. (:1 B21 j 13/14 This mvfintlon relates to a forgmg Press provided with [58] Field of Search 72/361, 427 transport tongs- The forging produced y the Press is provided with a flash which has areas which can 5 References Cited readily be engaged by the transport tongs.

UNITED STATES PATENTS 9 Claims, 9 Drawing Figures 2,603,987 7/1952 Lyon 72/361 PATENTEB FEB2 5 I975 SHEET U 0F 5 A Qt PATENTED 53251975 3, 867. 830

SHEET 5 OF 5 Fig. 9

FORGING PRESS The present invention relates to a forging press, and more especially to a forging press provided with transport tongs.

It is known that certain pressings or forgings are formed on automated hydraulic or mechanical forging presses with a flash which projects transversely to the pressing direction. This flash serves on the one hand as a cushion when the punch and die meet one another and thus prevents the undesirable hard-on-hard impact" which results in premature wear of the tools and severe stress on the body of the machine. Since, in view of the need accurately to maintain the prescribed punch stroke, it is not possible to provide a strong support for the die and/or punch, the shape of such a flash provides for damping of the punch strokes, which take place with very large forces. The gap provided between the facing end faces of the die and the punch, into which the flash flows during the forming process, also serves to receive the excess material above a calculated value.

If the closing movement of the tongs takes place in the plane of the flash, it is not possible to transport these articles by the periphery of the flash, since the outer edge of the flash can assume any shape and hence perfect centering of the pressing before the next forming station is no longer ensured. As is known to those skilled in the art, such pressings, after carrying out the pressing operation, are passed to the waiting grippers of the tongs by means of ejector pins which penetrate through the body of the die and are transported by the tongs to the next press station. The closing movement of the tongs takes place vertically to the plane of the flash, that is to say the flash is gripped on its flat faces which are opposite one another. Because of the way in which the movement takes place, the tongs can however only be used up to transporting capacities of a maximum of 50 pressings per minute. Since the automatic presses which are customary nowadays work with average outputs of 120 to I50 pressings per minute the use oftongs which work in this way is no longer possible.

According to the present invention there is provided a forging press equipped with tongs for transporting a forging from the press, the press including a die, and a reciprocable punch adapted to co-operate with the die in'a working zone to produce a forging, the stroke of the punch being such that the punch and die in their operative position in the working zone are spaced apart to provide a gap therebetween which communicates with a recess extending in the direction of the axis of the press such that a peripheral flash of a forging is formed in the gap and recess, the recess being positioned such that the portion of the flash produced therein can be engaged by the tongs.

An illustrative embodiment of the present invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a horizontal section of a device for the manufacture of tilting levers;

FIG. 2 is a plan view of the forging with the flash;

FIG. 3 is a side view of the matrix with the transverse transport tongs opened;

FIG. 4 is a side view corresponding to FIG. 3 but shows the arms of the tongs in their pre-gripping position;

FIG. 5 shows the pressing, provided with the flash, in the grip of the transverse transport tongs;

FIG. 6 is a cross-sectional representation along line VIVI in FIG. 5;

FIG. 7 illustrates the transport of the pressing from the last forming station to the de-flashing station;

FIG. 8 is a plan view of a pressed elbow before de flashing; and

FIG. 9 shows a modification of the device.

The device shown in the drawing represents a press station of an automatic multi-stage transverse-transport forging press. The blank which is preformed in a known manner in press stations which are not shown is finally formed in the press station shown and is subsequently de-flashed.

The device shown in FIG. 1 omitting unimportant details, represents a fixed die 2 and a reciprocating punch 3. The finished shape of the forging, in the present case, a shaped lever 1, is preformed partly in the end face of the die 2 and partly in that of the punch 3. The die 2 and the punch 3 are surrounded on the sections which face one another, by a ring 5.

Ejector pins

6, 7 and 8 are slidably mounted in the die body, and by means of these the finished pressed article can be pushed out of the die.

According to FIG. 1, the punch 3 is the nearest position away from the die and in which the shaping of the forging 1 is finished and the forging can be ejected for transportation onto the deflashing station. In this position, the two mutually facing end faces of the die 2 and punch 3 do not touch, as is clearly shown by FIG. 1, but are separated from one another by a gap of height a. During the forming process this gap is filled with a flash 9 which sourrounds the forging l on all sides, as is shown in particular by FIG. 2. This flash 9 serves to balance the unavoidable difference in the distribution of the material. The circumferential surface of the flash 9 remains at a distance 10 from the inner wall of the ring 5, or can touch the ring in an irregular fashion, depending on the resulting excess material.

In addition to this balancing feature the flash 9 performs a further very important function: it prevents the end faces of the die 2 and of the punch 3 from striking one another during the pressing process, which would lead to premature wear of the tools and to unacceptable stresses on the machine frame. The flash 9 thus acts as a buffer.

As can furthermore be seen from FIG. 1, the punch 3 is provided with a recess 11 which is wedge-shaped in cross-section and which ends in the gap between the punch and die and is filled with flash material. This recess, which in the present embodiment is produced by chamfering the edge of the punch head is defined on the plane outside by the inner wall of the ring 5. In the device shown, four such recesses 11 spaced apart by relative to one another, are provided and lead to a situation where the flash 9, during the pressing process, also extends to the recesses 11 and fills these. After completing the pressing process according to FIG. 1, the flash 9 thus has four projections 12 staggered by 90 relative to one another. The outward-pointing faces 13 (FIG. 2) of the projections 12 are substantially plane. in accordance with the local construction of the inner wall of the ring 5] The forging can be gripped by the tongs on these plane faces 13, the distance of each of which from the press axis P is accurately defined and,

can be transported further in an accurately centered position.

The thickness a of the flash 9 is calculated precisely and can also be deduced from the correspondingly restricted stroke of the punch 3. When the punch strikes the pressing blank which is lying in the die, the material of the pressing blank flows and in particular fills the four recesses 11. The circumferential parts 14 of the flash 9 which are located between the projections 12 have a wavy irregular defining surface, since in these zones the material balancing already mentioned takes place.

FlG. 3 shows the upper arm 15 and lower arm 16 of the transport tongs in the opened position. The drawing clearly shows the die 2 with the die cavity 17, and the ring which surrounds the die 2 and is provided with four plane faces 18. When the tongs assume their pregripping position, the upper arms of the tongs move in the direction of the arrow 20 and the lower arms of the tongs 16 move in the direction of the arrow 21 until the holding faces 22 of the tong shoes 23, are in the same plane as the plane faces 18 of the flash 9.

In this pre-gripping position of the tongs, the pressing l is released from the die 2 by the ejector pins 6, 7 and 8 (FIG. 1) and pushed into engagement with the tongs (FIG. 4). Due to the provision of the projections 12 provided with the plane faces 13 (FIG. 2) the pressing 1 provided with the flash 9 is now centered perfectly and can be conveyed, by means of the transverse transport tongs, to the deflashing station or a further forming station without the risk of any undesired movement.

FIG. 5 shows the forging or pressing l in the grip of the transverse transport tongs. The detailed representation according to FIG. 6 clearly shows the design of the projection 12. against the plane face 13 of which the holding face 22 of the tong shoe 23 rests.

FIG. 7 illustrates how the transverse transport tongs convey the pressing or forging in the direction of the arrow 24 from the last forming station to the deflashing station. The deflashing station has a deflashing die 25 in which the flash 9 is severed from the pressing or forging 1.

In a modification of the above device it would be possible without difficulty, to provide on the periphery of the flash 9 three projections 12 which in each case are offset by 120 relative to one another or two projections which are opposite one another and offset by 180 relative to one another. it is also possible to provide a single projection 12, as will be explained below in relation to FIG. 8.

FIG. 8 shows, in plan view, an elbow member 26 provided with a flash 27. The flash 27 projects outwards in both directions in the middle plane of the elbow 26. However, the two end faces 29 and 30 of the elbow 26 are not provided with a flash portion. The two mutually matching die members of the die and of the punch are so constructed and arranged in the present case, that the two end faces 29 and 30 of the elbow 26 are formed on corresponding plane faces of the ring 5, whilst a projection 28 is merely provided on the point of the flash.

27 which is spaced from the point 31 of the elbow; this projection 28 corresponds to the projections 12 of the embodiment already described. Hence, in the present instance, a single projection 28 suffices for centering the pressing in the tongs since the upper arms of the tongs can without difficulty engage on the accurately positioned plane faces 29 and 30. In this case, the lower part of the tongs merely has one tong shoe which rests on the outer face of the projection 28.

In the embodiment according to FIG. 1 the recess 11 which serves to form the projection 12 was produced by chamfering the edge of the punch head. ln principle it would also be possible to provide the corresponding recess in the die or in the adjoining inner wall of the ring 5 or both on the periphery of the punch head and in the defining ring or both in the die and on the punch head.

Whilst according to FIG. 1 the punch and die are surrounded by a ring 5, it is also possible to dispense with this ring by constructing the device, for example, according to FIG. 9. Here the punch 32 projects into a corresponding blind hole of the die 33 and the two halves of the die are machined in the end face of the punch head and in the bottom of the blind hole.

1 claim:

1. In a forging press including tong means for transporting a forging from the press, the invention which comprises a. a die member; and

b. a punch member mounted for axial reciprocation relative to said die member, said punch member being adapted to co-operate with said die-member in a work ing zone to produceaforging :the stroke of said punch member being such that said punch and die members in their operative position in the working zone are spaced apart to provide a gap therebetween so that a peripheral flash of the forging is formed in the gap;

c. at least one of the adjacent surfaces of said die and punch members containing in laterally spaced relation to said working zone a recess in communication with said gap, said recess extending axially of the press so that the flash extends into the recess to define an axial flash projection on the forging, said recess being so arranged that the flash projection produced therein is adapted for engagement by said transport tongs.

2. A press according to claim 1 in which said punch has a chamfered surface which in part defines said recess.

3. A press according to claim 1, in which the gap completely surrounds the members of the die and punch which produce the forging, the gap further communicating with two pairs of opposed recesses all of which recesses extend in the direction of the axis of the press.

4. A press according to claim 1 which includes a member having a plane surface surrounding the working zone, said plane surface in part defining said recess.

5. A press according to claim 1, in which said recess is wedge shaped with the broadest part of the wedge communicating directly with the gap.

6. A press according to claim 1 in which said recess is formed in said die.

7. A press according to claim 1 which includes a plurality of the said recesses.

8. A press according to claim 1 for producing an elbow shaped forging in which the members of the die and punch which produce the forging are provided with facing end portions which communicate with plane faces of a member surrounding the working zone, the recess being positioned adjacent the apex of the elbow.

9. A press as defined in claim 1, wherein said recess has a planar axially extending surface which defines on the outer periphery of the flash projection a planar surface for gripping by the tongs.

Claims

1. In a forging press including tong means for transporting a forging from the press, the invention wHich comprises a. a die member; and b. a punch member mounted for axial reciprocation relative to said die member, said punch member being adpated to co-operate with said die member in a working zone to produce a forging, the stroke of said punch member being such that said punch and die members in their operative position in the working zone are spaced apart to provide a gap therebetween so that a peripheral flash of the forging is formed in the gap; c. at least one of the adjacent surfaces of said die and punch members containing in laterally spaced relation to said working zone a recess in communication with said gap, said recess extending axially of the press so that the flash extends into the recess to define an axial flash projection on the forging, said recess being so arranged that the flash projection produced therein is adapted for engagement by said transport tongs.

6. A press according to claim 1 in which said recess is formed in said die.