US3085812A

US3085812A - Pressing tools

Info

Publication number: US3085812A
Application number: US65205A
Authority: US
Inventors: Rosenthal Salli; Salter Frank Sidney
Original assignee: Loewy Engineering Co Ltd
Current assignee: Loewy Engineering Co Ltd
Priority date: 1960-10-26
Filing date: 1960-10-26
Publication date: 1963-04-16
Anticipated expiration: 1980-04-16

Description

April 1963 s, ROSENTHAL ETAL 3,085,812

PRESSING TOOLS 4 Sheets-Sheet 1 Filed Oct. 26, 1960 INVENTORS FIGII SALLI, ROSEN'IHAL April 16, 1963 s. ROSENTHAL ETAL 3,085,812

PRESSING TOOLS Filed Oct. 26, 1960 4 Sheets-Sheet 2 April 16, 1963 S. ROSENTHAL ETAL PRESSING TOOLS Filed Oct. 26, 1960 4 Sheets-Sheet 3 In I" l I I I I 1 2', 3a

' u 13 IO 48 50 I3 ll 10 H6 1]: INVENTORS SALLI ROSENTHAL FRANK SIDNEY S TER A l I April 16, 1963 s. ROSENTHAL ETAL 3,085-812 PRESSING TOOLS Filed Oct. 26, 1960 4 Sheets-Sheet 4 FIG III FIGYUI INVENTORS SALLI ROSENTHAL FRAN SIDNEY SA TER United States Patent PRESSING TOQLS Salii Rosenthal, Poole, Dorset, and Frank Sidney aiter, Parkstone, Dorset, England, assignors to The Loewy Engineering Company, Limited, Bournemouth, England, a corporation or Great Britain Filed Get. 26, 1960, Ser. No. 65,295 13 Claims. (til. 2794) This invention relates to pressing tools and, more particularly, to a device for securing a pressing tool of a press to a socket-shaped holder. The tool may be the pressing stem of an extrusion press, or the punch of a piercing or drawing press.

The conventional type of locking means for these tools comprises threaded bolts and nuts. The exchange of a tool was, therefore, an operation which took considerable time. During this time, the press was out of production.

'It is, therefore, an object of the present invention to provide a device for securing a pressing tool of a press to a socket-shaped holder which permits the tool to be more quickly attached to or detached from its holder than has been heretofore possible.

It is a further object of the present invention to provide a device for securing a pressing tool of a press to a socket-shaped holder, which, whilst enabling the tool to be readily attached to or detached from the holder, provides a firm grip for the tool so that it can Withstand any forces which tend to pull the tool out of its holder.

It is still a further object of the present invention to provide a device for securing a pressing tool of a press to a socket-shaped holder, which has no threaded ele ments.

It is finally an object of the present invention to provide a device for securing a pressing tool of a press to a socketshaped holder in a press of large-pressure capacity, such as a metal extrusion press or a forging press.

According to the present invention, a device for securing a pressing tool of a press to a socket-shaped holder, the said tool having a stern portion and a head portion, which latter enters the opening of the holder, comprises a number of locking plungers provided in said holder and movable under pressure into engagement with said tool at such an angle that the tool is axially thrust against the bottom wall of the opening in the holder.

The pressure means acting on the plungers may include fluid-pressure chambers which are formed at the outer ends of the plungers. Alternatively, springs may be used instead for urging the plungers into their operative positions.

In accordance with a further feature of the invention, the plungers may be operated by mechanical means, such as eccentrics, or toggles and the like, arranged at the outer ends of said plungers.

The direction of radial movement of the plungers towards and away from the pressing tool may form a slight angle with the plane which is perpendicular to the main axis of the pressing tool, the force exerted by each plunger having a component acting parallel to the axis of the pressing tool and directed towards a co-operating part of said tool.

For a better understanding of the invention and to show how it may be carried into effect, the same will now be described with reference to the accompanying drawings, wherein:

FIGURE 1 is a schematic sectional view of a locking device according to the present invention incorporated in the holder for the pressing tool of an extrusion press, the pressing tool being shown in dotted lines and removed from its holder,

FIGURE 2 is a sectional view similar to FIGURE 1, in which the pressing tool is secured to its holder,

Efidfifil? Patented Apr. 16, 1953 FIGURE 3 is two half sectional views of the embodiment shown in FIGURE 1 and taken along the line A--A and B-B respectively of that figure,

FIGURE 4 is a schematic sectional view of a further embodiment of the invention, the pressing tool being shown in dotted lines and removed from its holder,

FIGURE 5 is a schematic sectional view of yet a further embodiment of the invention, the pressing tool being shown partly removed from its holder,

FIGURE 6 is a view of the embodiment shown in FIGURE 5 with the pressing tool secured to its holder,

FIGURE 7 is a schematic sectional view of a further embodiment of the invention, the pressing tool being shown removed from its holder,

FIGURE 8 is a sectional view of the embodiment shown in FIGURE 7, with the pressing tool secured to its holder, and

FIGURE 9 is a schematic sectional view of a final embodiment of the invention, in which the pressing tool is shown secured to its holder.

In all the figures of the drawings, like parts have been designated by common reference numerals.

With particular reference to FIGURES 1 to 3, numeral 10 designates the front part of a hydraulic main ram of an extrusion press, the ram being displaceable in a hydraulic main cylinder (not shown). A sliding cylindrical crosshead I1 is attached to the main ram by a series of screw bolts 12. A pressure-piece 13 in the form of a thrust block is arranged inside the crosshead 11, which latter defines an opening or cavity adapted to reeive the enlarged head 14 of a pressing stem 15. The pressure-piece 13 is secured to the main ram 10 by any suitable fastening means, such as screw bolts 16.

The enlarged head 14 of the pressing stem has a conical portion 17. The head 14 of the stem is also provided with a flanged extremity 1 8 Which defines one side of a circumferential groove 19, the other side of which is partially defined by means of splines 14A. The end face 20 of the enlarged head is adapted to abut the flat end face 21 of the thrust block 13 when the thrust block and pressing stern are arranged in thrust-transmitting contact with each other, as will later be described.

Distributed (preferably equally) about the circumference of said crosshead 11 are a series of bores housing displaceable plungers 22, the bores being arranged at a small angle with reference to a plane perpendicular to the main axis of the pressing stem 15. The plungers are themselves bored and each houses a piston 23 provided with a piston rod 24; a retaining plate 25 closes each bore housing its plunger, the plate being suitably fixed by welding or the like to the crosshead II in the manner shown, while the free end of piston rod 24, which is threaded, passes through an aperture in the retaining plate 25 and is attached thereto by means of a nut 26 threaded on said free end. The piston rod is provided with a pair of

axial bores

27, 28, the bore 27 opening at the rear of the piston, and the bore 23 at the front thereof. Both bores are connected to at least one source of pressure fluid, as will be later described. The bore of the plunger 22 housing the piston 23 and rod is closed by means of an annular head 29, which has an opening through which the piston rod 24 passes. Each plunger 22 is provided with an indentation 3th at one end thereof adapted to bear on a portion of the pressing stem 15, as will be later described.

When the pressing stem 15 is to be secured to the main ram 10, each plunger stands retracted in its bore in the crosshead I11, and the pressing stem is inserted, as will presently be more fully described, into the cavity defined by the crosshead 11, until it abuts the face 21 of the thrust block 13. Pressure is then admitted through the piston rod bore 28 to the front face of each piston and is exhausted from the rear of the piston through the bore 27 which will cause each plunger 22 to advance out of its bore and into the circumferential groove 19 to contact with its indentation St) the flanged extremity of said pressing stem. The inclination of the plungers is such that an effective wcdging action takes place between plunger indentation and stem flange. To retract each plunger 22 for the release of the pressing stem from the main ram 10, pressure is admitted to each piston rod 2 through the bore 27, and pressure is exhausted through bore 28.

Secured to the foremost end of crosshead 11 by means of the bolts 12., there is also provided a flanged internatly splined bearing 3*, springs in the form of Bellevillc washers 32 being provided between nuts 33 and the flanged portion of the bearing so as to urge the bearing 31 towards the crosshead 11. The enlarged head 14 of the stem is splined conjugately to this hearing. The splines permit relative lengthwise movement between the enlarged head 1 of the pressing stem 15 and the caring 31 when the former is correctly positioned in relation to the bearing. The degree of endwise movement is limited by abutment of the end face 21 of the thrust block 13 with the end 20 of the enlarged head.

A bearing moving means is provided for use when the plungcrs 22 are retracted, and this comprises a pressurefiuid duct 34 opening into at least one chamber 35 in the crosshead 11, and a displaceable piston 36 disposed within the chamber 35 which abuts the inner side of the flange 37 of the bearing 31. The arrangement is such that pressure within the duct 34 will displace the piston 36 to move the bearing 31 against the action of the Belleville washers 32. Thus, when the bearing 31 is fully advanced, the pressing stem 15 may have its splines aligned with the openings between the splines of the hearing and then advanced through the latter until the enlarged head 14 thereof abuts the end face 21 of the thrust block 13. Then the pressing stem is angularly displaced or rotated relative the bearing 31 to thereby bring the top lands of both sets of splines into aligned relationship. The release of pressure from the chamber 35 will permit the piston 36 and the bearing 37 to return to their original positions under the action of the Belleville washers 32. The plungers 22 are then caused to advance to their operative positions, as previously described, and the pressing stem 15 is thus secured to the ram 10. To separate the stem from the ram, the steps described above are reversed, i.e., the plungers 22 are withdrawn, the bearing 31 is advanced, the pressing stem 15 is angularly displaced relative the bearing to bring the splines of the stern and of the bearing out of alignment, and the pressing stem is then withdrawn.

Referring to FIGURE 4, the operation and structure of this embodiment are similar to that of FEGURES 1, 2 and 3, except that the internally splined bearing comprises a composite structure constituted by a tubular element 39 provided with a flange 4t) and a ring 41 internally grooved at 42 to receive said flange 40, whereby the tubular element 39 may be angularly displaced, or rotated relative the ring 41 in order to bring the splines of the enlarged head 14 and of the bearing into the positions previously described. It will be remembered that in FIGURE 1, the pressing stem 15 was angularly displaced relative to the stationary bearing 31 in order to achieve this same result.

Referring to FIGURES and 6, the internally splined bearing of the previous embodiments is replaced by a flanged tubular plain bearing 43 secured to the crosshead 11 by means such as bolts 44 (FEGURE 6) or the like. The crosshead 11 is provided with an outwardly flared cavity 45 and the outer periphery of the tubular bearing 43 is of complementary frusto-conical configuration, so that when the heel 46 of the flange of the bearing 43 abuts the face of the crosshead 11, the inner circumference of the crosshead defining the cavity snugly receivcs the frusto-conical periphery of the hearing. The upper portion 43A of the tubular bearing 43 is of greater length than the lower portion thereof and is slotted to allow passage of the plunger 22, as will be further described below. The enlarged head 14 of the pressing stem is, in this case, of cylindrical configuradon, with a central groove 58 defined by a pair of spaced

flanges

49, 56.

With the plungers 22 retracted, as already described, the pressing stem 15 is suspended with its enlarged head 14- in the inclined position shown in FIGURE 5, and, in this manner, is inserted through the tubular bearing 43. The length of the lower inner surface portion 43B of the bearing is proportioned so that with the stem 15 inclined, as shown, the enlarged head thereof slides along said inner surface until the rear face 49A of the flange 49 abuts the front face 43C of the flange of the bearing 43. When this abutment has occurred, the pressing stem is tilted and thereby lowered into a substantially horizontal position. During the lowering operation, the enlarged head of the stem slides along the lower inner portion 438 of the bearing and oif said inner portoin on to the inner surface of the crosshead. The operation continues until the end of the enlarged head abuts the end face 21 of the thrust block 13, whereupon the plungers may be advanced, as already described, to secure the pressing stem to the holder.

Referring to the emboidment shown in FIGURES 7 and 8 of the drawings, the hydraulically controlled plunger system comprises an assembly similar to that previously described in connection with the previous examples except that a lining cylinder 52 is fitted in each of the crosshead bores. A plunger 22 is displaceable within each of said lining cylinders and the latter are positioned in the crosshead 11 by means of retaining plate 53. The lining cylinder 52 also circumscribes the annular head 29 in the manner shown and this head is provided with a guide pin 54 slidably located within an opening in said retaining plate, so that as the plunger 22 and the head 29 reciprocate, the parts are maintained in properly aligned relationship.

In the present example the enlarged head 14 of the pressing stem 15 is of frusto-conical configuration, being tapered outwardly towards its end, and a ring member 55 is fitted to this head by means of its conjugately tapered bore, as shown. The ring member 55 is provided with a circumferential groove 56. With the plungers 22 in their retracted positions, the pressing stem 15 and ring member 55 may thus be advanced until the base 20 of the enlarged head abuts the end face 21 of the thrust block 13. The plungers 22 are then advanced in the manner already described and into the groove 56 of the enlarged head 14 to lock the assembly together. As shown, the stem 15 is provided with an auxiliary and detachable lifting gear 57 to facilitate displacement of the enlarged head of the stem in relation to the internal bore of the crosshead 11.

Now referring to the embodiment shown in FIGURE 9, the locking device comprises a plurality of displaceable plungers 22, each slidably received within a lining cylinder 5'2 in a similar manner to the plungers referred to in FIGURES 7 and 8; each of the plungers is provided with an enlarged piston head 58 which has a counter-bored portion 59. A retaining plate 53 secured by means of belts or the like to the crosshead l1, retains each plunger assembly 22. in position; a compression spring 60 is arranged intermediate the counter-bored portion of the plunger and the inner surface of the retaining plate. A guide rod 61 is screw threaded at one end Within the counter-bored portion 59 of each plunger 22 at at its opposite end passes through a bore formed in the retaining plate 53 and is attached thereto by a nut 62. The lining cylinder 52 is provided with a conduit 63 which communicates with a sourse of fluid-pressure and with a chamber 6% defined between the head 58 and body portion of the plunger 22 and the periphery of the lining cylinder. Pressure within the conduit 63 and chamber 64- will displace the piston head 58 upwardly to retract plunger against the action of the compression spring 60. When the plunger 22 is in its fully retracted position, a port 65 in the lining cylinder is uncovered by the piston head '58 so that fluid-pressure may be admitted through a passage 66 in said cylinder to actuate the piston 36 and thereby the ring 41 of the composite bearing which is of similar construction to that already described in connection with FIGURE 4. The main ram is provided with a hydraulically actuated ejector rod 67 not forming part of the present invention but which may be used to facilitate removal of the pressing stem 15.

Referring again to FIGURE 1, each of the

bores

27, 23 of the piston 23 are connected through suitable manifolds (not shown) to a pressure-fluid circuit, including a pump 68 and a storage container 69. The pressure-fluid may be any liquid having a suitable viscosity; it may be oil or grease.

Valves

70, 71, 72 and 73 are provided in the pressure-fluid circuit for purposes which will become presently apparent. The valve 70, when open, enables pressure-fluid to flow from the pump 68 through the associated portion of the circuit to the bore 28 in the piston rod 24 and thereby to the front face of the piston to cause the associated plunger 22 to be displaced into its operative position in which it locks the pressing stem. During this operation, the valve 72 will also be open to enable pressure-fluid to be exhausted from the rear of the piston through the bore 27 and to the storage container 69. To retract the plunger 22 it is merely necessary to open valves 71 and 73, the remaining valves being closed, whereby pressure-fluid through the bore 27 will cause the plunger 22 to retract, pressure-fluid being exhausted from the front face of the piston through the bore 28 and back to the storage container 69. A pressure gauge 76 is provided to indicate correct pressure which has to be maintained during operation of the plunger-s 22.

As has been previously described, to be able to with draw the pressing stem from its holder, it is necessary to unlock the bayonet joint formed between the bearing 31 and the head 14 of the pressing stem by relative rotation of the pressing stem and bearing, this being only possible after the bearing has released its axial pressure on the pressing stem. To this end opening of valve 74 will permit pressure-fluid to flow into the chamber 35 in the crosshead 11 and move the piston 36 outwardly and thereby the bearing 31 against the action of the Belleville washers 32. To return the bearing to its operative position, it is merely necessary to close valve 74 and open valve 75 whereby pressure-fluid isv exhausted to the storage container 69.

The aforementioned valves of the pressure-fluid circuit may be operated manually or by automatic servo-control means giving the correct sequence of operation.

Referring to the pressure-fluid circuit to be used in connection with the apparatus shown in FIGURES 5 and 6, this comprises again a pump 68 and a storage container 69.

Valves

77, 78, 79 and 80 are provided in the circuit and the arrangement is such that depending upon which pair of valves are opened together, pressure fluid will be fed either to the front face of the piston 23 and exhausted from the rear thereof to advance plunger 22, or exhausted from the front face of the piston and fed to the rear thereof to retract the plunger.

The pressure-fluid circuit to be used in connection with the apparatus shown in FIGURES 7 and 8 may be identical to that shown in the previous example.

Referring to FIGURE 9, pressure within the conduit 63 from a pressure source (not shown) Will displace the piston head 58 upwardly to retract the plunger against the action of the compression spring 60. Release of pressure will cause the compression spring to return the plunger to its operative or locking position. When the plunger is in its fully retracted position, a port 65 in the lining cylinder is uncovered by the piston head 58 so that fluidpressure is admitted through the passage 66 in the cylinder to actuate the piston 36 and thereby the ring 41 of the composite bearing.

What we claim is: 1

1. A device for securing a pressing tool of a press to a socket-shaped holder, said tool having a stern portion and a head portion, the latter entering an opening of said holder, said device comprising a plurality of locking plungers radially movable with respect to the tool axis, said head portion carrying a circumferential groove into which said plungers are movable, so as to engage therewith, the direction of movement of said plungers being inclined relative to the tool axis, so as to exert a thrust on the head portion of the tool which has a component parallel to the tool axis.

2. A device for securing a pressing tool of a press to a socket-shaped holder, according to claim 1, having an internally splined bearing on said holder, said bearing being arranged adjacent said holder for limited relative axial displacement, the head portion of said tool being splined conjugately With said bearing.

3. A device for securing a pressing tool of a press to a socket-shaped holder according to claim 1, having resilient connecting means, arranged intermediate said splined bearing and said crosshead, said connecting means being adapted to urge one set of aligned splines toward the other set and bearing moving means for displacing said splined bearing axially of the crosshead against the action of said resilient connecting means.

4. A device for securing a pressing tool of a press to a socket-shaped holder according to claim 1, comprising a tubular body member and a ring circumscribing one end of said body member, said body member being arranged for rotation internally of said ring, said ring having -a side face in engagement with said bearing moving means.

5. A device for securing a pressing tool of a press to a socket-shaped holder according to claim 1, comprising a tubular body member and a ring circumscri-bing said body member and in which said bearing moving means have a pressure fluid duct, opening into a chamber in said holder, and a displace-able piston arranged within said chamber and having one end thereof abutting the side face of said ring.

6. A device for securing a pressing tool of a press to a socket-shaped holder, said tool having a stem portion and a head portion, said holder including a crosshead having a cavity to receive the head portion of said tool, a thrust block provided within said crosshead and radially movable plungers engageable with the head portion of said tool in such directions that the end face of the head portion of said tool is thrust against said thrust block.

7. A device for securing a pressing tool of a press to a socket-shaped holder, said tool having a stem portion and a head portion, an internal plain bearing provided at the outer end of said holder, said bearing having a frusto-conical outer periphery received within a bore of complementary configuration formed internally of said holder and in which one portion of said bearing is of greater length than the diametrically opposite portion thereto, said first-mentioned portion being slotted to permit passage of a plunger when the latter moves into or away from its advanced position.

8. A device for securing a pressing tool of a press to a socket-shaped holder, said tool having a stem portion and a head portion, said device comprising a plurality of locking plungers radially movable with respect to the tool axis and having an axial bore, a piston accommodated in each of said bores, a piston rod for each piston, said piston rod being provided with a pair of internal ducts opening respectively at the front face of the piston and at the rear thereto, said ducts being alternately connectable to a source of fluid pressure, whereby said plunger is advanced or retracted.

9. A device for securing a pressing tool of a press to a socket-shaped holder, said tool having a stem portion and a head portion, the latter entering an opening of said holder, said device comprising a plurality of locking plungers, radially movable with respect to the tool axis, a bearing on said holder, means for moving said bearing relative to said holder in the axial direction of said tool, a fluid pressure chamber for each of said plungers and a fluid pressure chamber for said bearing moving means, an internal duct connecting said two fluid pressure chambers to each other and a port which is uncovered When said plungers are moved towards said tool.

10. A device for securing a pressing tool to a socketshaped holder in a press, said tool having a stem portion and a tapered head portion insertable into said holder, said device comprising a plurality of locking plungers distributed circumferentially in said holder and around said tapered head, fluid-pressure means in said holder for moving said plungers relative to said tapered head, said plungers being so arranged in said holder and relative to the axis of said tool that the pressure exerted by said plungers on said tool head has a component Which is parallel to the tool axis and directed towards the closed end of said holder, and means cooperating with the tapered surface of the tool head for centering the tool relative to the axis of said holder.

11. A device for securing a pressing tool to a socketshaped holder in a press according to claim 10, in which said centering means comprise a ring-like member axially displaceable relative to said tapered tool head and having a conical internal surface matching the taper of said tool head, and fluid pressure means for moving said ring axially relative to said tool head.

12. A device for securing a pressing tool to a socketshaped holder in a press according to claim 11, in which the fluid pressure means of said centering means comprise a plurality of plungers distributed circumferentially around said centering ring.

13. A device for securing a pressing tool to a socketshaped holder in a press according to claim 12, having means for controlling interdependently the supply and release of pressure fluid to said locking plungers and to said centering plungers.

References Cited in the file of this patent UNITED STATES PATENTS 2,154,738 Fisher Apr. 18, 1939 2,529,772 Highberg Nov. 14, 1950 2,583,264 l-lerrmann Jan. 22, 1952 2,821,401 Eben Jan. 28, 1958

Claims

1. A DEVICE FOR SECURING A PRESSING TOOL OF A PRESS TO A SOCKET-SHAPED HOLDER, SAID TOOL HAVING A STEM PORTION AND A HEAD PORTION, THE LATTER ENTERING AN OPENING OF SAID HOLDER, SAID DEVICE COMPRISING A PLURALITY OF LOCKING PLUNGERS RADIALLY MOVABLE WITH RESPECT TO THE TOOL AXIS, SAID HEAD PORTION CARRYING A CIRCUMFERENTIAL GROOVE INTO WHICH SAID PLUNGERS ARE MOVABLE, SO AS TO ENGAGE THEREWITH, THE DIRECTION OF MOVEMENT OF SAID PLUNGERS BEING INCLINED RELATIVE TO THE TOOL AXIS, SO AS TO EXERT A THRUST ON THE HEAD PORTION OF THE TOOL WHICH HAS A COMPONENT PARALLEL TO THE TOOL AXIS.