US2996025A

US2996025A - Readily changeable die assembly for power presses

Info

Publication number: US2996025A
Application number: US604437A
Authority: US
Inventors: Georgeff Vasil
Original assignee: Danly Machine Specialties Inc
Current assignee: Danly Machine Specialties Inc
Priority date: 1956-08-16
Filing date: 1956-08-16
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

Aug. 15, 1961 v. GEORGEFF READILY CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Filed Aug. 16, 1956 6 Sheets-Sheet 1 INVENTOR. ZS/L 6EOA 6FF TTORNEY Aug. 15, 1961 v. GEORGEFF 2,996,025

READILY CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Filed Aug. 16, 1956 6 Sheets-Sheet 3 TORNEY Aug. 15, 1961 V. GEORGEFF READILY CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Filed Aug. 16, 1956 6 Sheets-Sheet 4 TI L3 INVENTOR. Wis/L 660,965?

, A OPN EY Aug. 15, 1961 v. GEORGEFF READILY CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Filed'Aug. 16, 1956 6 Sheets-Sheet 5 INVENTOR.

1425/4 GEORGE/ F A ORNEY Aug. 15, 1961 v. GEORGEFF 2,996,025

READILY CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Filed Aug. 16, 1956 6 Sheets-Sheet 6 INVENTOR. Wis/L GEORGEFF BY MtEQw ATTORNEY Fig ii United States Patent O 2,996,025 READILY 'CHANGEABLE DIE ASSEMBLY FOR POWER PRESSES Vasil Georgelf, La Grange Park, Ill., assignor to Danly Machine Specialties, Inc., Chicago, 111., a corporation of Illinois Filed Aug. 16, 1956, Ser. No. 604,437 5 Claims. (Cl.-11349) My invention relates to. a. readily changeable: die. assembly for power presses and more. particularly to an assembly which permits the. diesv used on a press to be. changed in a rapid, convenient and expeditious manner.

In operation of. a power press, one. of the mostdiflicult. and. time consuming, operations which must be. performed is. changing the press setup? when. a new part is. to be produced on the. press. In the. courseof this changeover; the. old dies must be removedfromthe press and. the new dies must be accurately locatedon the press bed so that the upper die may be secured to the press. slideand the lower die may be secured to the. press bed. The labor cost. of this operation is high as a result of the: high. hour- 15 wage. rate of skilled die setters. Owing to the high cost. of. setting upa press to produce a part, manufacturers make large runs of a singlepartbefore changing the setup of. a. press. While this expedient saves. labor, it introduces the. necessity of storing and handling a very large numher ofv parts- Imbalances in. the manufacturers inventory result. In the manufacture of consumer goods, frequent model changes render obsolete many of the parts previously run, resulting in loss to the manufacturer. One solution to the problem is to provide a large number of presses, each, using a different set. of dies. This. solution clearly is an uneconomical one.

It has been suggested in the prior art. that the. dies to be assembled on the. press be nested and placed on tracks. which are. run into the press bedto permit the dies to be secured to the press slide and bed. Such a system has never been practicable in the prior art because of the difliculty of locating the dies properly and. the. difficulty of securing the dies to the press bed and to the press slide. Thev difliculty of securing a die to the press drawing slide is particularly evident in a press in which the drawing slide is mounted within a blank holderv slide.

I. have invented a readily changeable die assembly for power presses which permits the dies of a. press to be. changed in a rapid, convenient, and expeditious manner. My assembly includes means-for accurately positioning a die set run into the press. bed to permit the: diesv to be secured to the press inner slide and bed. I provide my assembly with means for rapidly and simply securing the dies to the press bed. My assembly permits the setup of a. press to be changed back and forth between two setups without the high labor cost involved in setting up operationsin the prior art.

An object of my invention is to provide a readily changeable die assembly for a power press which permits the press dies to be changed in a rapid, convenient, and expeditious manner.

Another object of my invention is to provide. a readily changeable die assembly for a power press which-accurately positions a die set-run into. the: press bed to perunit the dies to secured to the press slide and the press bed.

A further object of my invention is to provide a readily changeable die assembly for a power press including means for rapidly and simply securing a die to the press drawing slide.

Yet another object of my invention. is. to provide a readily changeable die assembly for av power press which permits the press setup to be changed back and forth 2. between two setups without the highlabor costs involved in changing dies in the prior art.

Other and further objects of. my invention will appear from the following description:

In. general my invention contemplates the. provision of a readily changeable die assembly for a power press having a frame and a bed and a drawing slide carried by the frame. for reciprocation with respect to the bed. My assembly includes a movable member. which may be a bolster or a ring carrying a bolster. I secure the lower die of a die set, including any upper die adapted to be: secured. to the press slide, to the bolster. A track supports the member for movement from a location adjacent the press to a: position over the press bed. I provide means for locating the member accurately on; the press bed to permit thev bolster or; bolster carrier to be secured to the press bed and to permit. the upper die: to be se.- cured to the press slide. My assembly has. means for rapidly and. simply securing the. upper die to the. press drawing slide. When. the setup of a. press with which my assembly is used is to be changed, the movable member and dies in the. press: are. released and run out of the press bed. and another member carrying the new die set is run into the. press bed. I provide. drive means for running the movable. member into and out of the press.

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction. therewith and in which like reference numerals are used to indicatelike. parts in the various views:

FIGUREl is a perspective view of a powerpress employing my readily changeable die assembly for power presses with parts broken away.

FIGURE '2 is a fragmentary front elevation of a power press employing my readily changeable die assemblyfor power presses showing a bolster on a carrier ring.

FIGURE 3 is. a sectional view of a power press employing my readily changeable die assembly for power presses taken along the line 3-3 of FIGURE 2, and showing a die set in place on a bolster.

FIGURE 4 is a perspective view of a pair of bolster carrier rings of my readily changeable die assembly for power presses with parts removed.

FIGURE 5 is a fragmentary sectional view of my readily changeable die assembly for power presses taken along the line 5--5 of FIGURE 3 and drawn on an en larged scale.

FIGURE 6 is a fragmentary sectional view of my readily changeable die assembly for power presses in a position of the bolster carrier ring where the bolster is not located over my positioning means.

FIGURE 7 is a sectional view of my readily changeable die assembly for power presses taken along the. line 7-7 of FIGURE 5.

FIGURE 8 is a fragmentary sectional. view of my readily changeable die assembly for power presses taken along the line 8-8 of FIGURE 3 and drawn on an en'- larged scale.

FIGURE 9 is afragmentary sectional view' of. one form olgdmeans for securing an upper die to the press drawing 5 e.

FIGURE 10 is a fragmentary top plan view taken along the line- 10-10 of FIGURE 9.

FIGURE 11- is a fragmentary bottom plan view taken along the line I I-II of FIGURE 9.

FIGURE 12 is a fragmentary sectional view of" another form of my means for securing an upper die to-the press drawing slide.

FIGURE 13 is a fragmentary elevation of the. form of my means for securing the inner slide shown in FIGURE 12 taken. along the line 13-13 of; FIGURE.v 12-.

Referring now to FIGURES l to- 3 of the drawings, the power press with which my readily changeable die assembly is used includes a frame, indicated generally by the reference character 10, having a front 12, a back 14, and sides 16 and 18. The press includes a bed 20 to which my bolster, to bedescribed hereinafter, is adapted to be secured. A respective inner slide 22 and a blank holder slide 24 are mounted for reciprocation with respect to bed 20 in frame in a manner known to the art.

Respective openings

26 and 28 in the front 12 and rear 14 of the press provide access to the area of the press between the

slides

22 and 24 and the bed 20. In order to permit entry of a bolster, to be described hereinafter, into the press from either side, I provide the respective sides 16 and 18 with openings 30 and 32. Four respective up

rights

34, 36, 38, and '40 having a hollow, rectangular cross-section are disposed at the respective corners of the press frame and separate the side openings of the frame from the front and rear openings. The

press tie rods

42, 44, 46, and 48, the function of which is known to the art,

4 unit. I fix a rack bar 90 formed with teeth 92 to the side 58 of carrier 56 by an convenient means such as welding or the like.

As can be seen by reference to FIGURES 2 to 4, frame 10 carries a bracket 94 which supports a motor 96 which drives a shaft 98. Shaft 98 carries for rotation with it a gear 100 which drives a pinion 102 fixed on a shaft 104 for rotation with the shaft. Any convenient means is employed to support shaft 104 for rotation on the frame 10. The end of shaft 104 remote from pinion 102 carries for rotation with ita pinion 106 adapted to engage the teeth of bar 90 to drive the connected carriers 54 and 56. It is to be understood that a similar drive could be provided for single unconnected bolsters.

Referring now to FIGURES 1 to 3 and 8, a plurality of bolts 108 disposed in vertical slots 110 in the sides of the bolster 112 pass through the holes 68 in the carrier sides 58 and 60 and into grooves 64. Nuts 114 are extend from top to bottom of the press through the

respective uprights

34, 36, 38, and 40. My construction of the press with uprights having a hollow, rectangular crosssection gives the press frame suflicient rigidity to withstand the shocks incident to its operation while permitting bolsters, to be described, to be run into the press through the press sides.

A pair of respective raised tracks or

rails

50 and 52 extend outboard from the bed through the side openings and 32. Any convenient means such as a table or the like, not shown for purposes of clarity in exposition, supports the lengths of

tracks

50 and 52 outboard of the press sides 16 and 18.

- In FIGURES l I have shown a form of my invention for use with presses having no die cushions including respective movable bolsters 49 and 51 carryingdie sets, to be described hereinafter. In presses provided with die cushions, die pins must be permitted to extend a distance below the bolster. Referring now to FIGURES 2 to 7, in order to permit movement of the bolster and pins into threaded on bolts 108 to secure the bolster 112 to the carrier ring. The lower die 117 of a die set has guide posts 116, two of which are shown, on which the. upper die 118 of a die set is placed. As is known in the art, posts 116 support the upper die 118 on the lower die 117 and position upper die 118 properly on the lower die.

and out of the press, I have provided my assembly with bolster carrier rings, indicated generally by the respective reference characters 54 and 56. Since the details of the construction for supporting movable bolsters 49 and 51 and carrier rings 54 and 56 on the rails and for moving the bolsters or rings into and out of the press are the same for both the bolster and the rings, for purposm of simplicity I will describe these structures in connection with the rings only. Each of the

respective sides

58 and 60 of each carrier 54 and 56 is formed with a pair of spaced recesses 62. A longitudinal groove 64 runs along the length of each of the sides 58 and "60 to provide a flange or lip 66 by means of which the carrier may be secured t'o'the press bed in a manner to be described. A plurality of bolt holes 68 leading from the upper surfaces of carriers 54 and 56 into the grooves 64 permit assembly of a bolster to the carrier ring in a manner to be described.

Referring now to FIGURES 5 to 7, a plurality of stub shafts 70 fixed in the

sides

58 and 60 of the carriers extend into the recesses 62 and carry bushings 72 which rotatably support wheels 74. I form each of the wheels 74 with a peripheral groove 76. Each of the carriers 54 and 56 normally rests by means of its wheels 74 on the

rails

50 and 52 with the rails in the wheel grooves 76. It will be seen that rails 50 and 52 guide the carriers in their movement into and out of the press in a manner to be described.

If desired, I may connect my carriers for movement as a unit to permit a new die set to be moved into the press while the set being replaced is moved out of the press. Referring again to FIGURE 4, I form the carrier 56 with a pair of elongated connecting

arms

78 and 80 having bifurcated ends. The bifurcated ends of

arms

78 and 80 fit loosely over

projections

82 and 84 formed on the carrier 54.

Pins

86 and 88 pass through the bifurcated ends of

arms

78 and 80 and through the

projections

82 and 84 to connect carriers 54 and 56 for movement as a In the form of my invention shown in FIGURES 2 to 7 the lower die 117 is secured to the bolster 112 in a conventional manner, as by bolts or the like. The movable bolsters 49 and 51 shown in FIGURE 1 are constructed similarly to carrier rings 54 and 56 to permit them to be secured tothe press =bed. Lower dies 117 are secured to the movable bolsters of FIGURE 1 in a conventional manner. It is to be understood that where the press with which my die assembly is used is of the type which is provided with a die cushion and die pins, it is necessary that I use separate movable carrier rings 54 and 56 to which the bolsters 112 are secured. When the press with which my assembly is used has a solid bed and no die cushion, the bolster plates themselves imay be provided with wheels to permit them to be moved into the press and no separate carrier rings are necessary. I have shown such bolsters 49 and 51 in FIGURE 1. That is, the movable bolsters 49 and '51 shown in FIGURE 1 for use with a solid bed press are alternative to the movable carrier rings '54 and 56 to which respective bolster plates 112 are secured.

In theposition of the parts shown inFIGURE l, a first die set carried by the bolster 49 is over the press bed and a second die set carried by the bolster 51 is positioned adjacent the press side 18 outboard of the press. When it is desired to employ the set of dies carried by bolster 51, the bolster 49 and the upper die carried thereby are first freed. Motor 96 is energized to drive pinion 106 to move bolster 49 away from the press and to move bolster 51: into position over the press bed.

- In the course of this operation, both bolsters are supported on rails 54} and 52. Motor 96 is energized until bolster 56 is approximately positioned over the press bed. It is to be understood that one of a pair of unconnected bolsters could be run out of the press and the other bolster carrying a new set could be run in in separate operations.

Referring now to FIGURES 2, 3, 5, and 7, I form each of the tracks 50and 52 with a pair of spaced, vertically-displaceable sections 120 located over the press bed. Each section 120 is secured by means such as welding or the like to a piston 122 disposed in a cylinder 124 formed in the press bed. A plurality of passages 126 in the bed provide a means by which fluid under pressure may be supplied to cylinder 124, to actuate the pistons 122 to raise the sections 120 of track to the level of the

tracks

50 and 52. A stop ring 128 adjacent the top of a cylinder 124 is engaged by a shoulder 130 on the associated piston 122 to limit the upward movement of the piston under the influence of fluid under pressure fed to the cylinder. When one carrier such as carrier 56 is to be moved into the press, and another carrier,

easeas such as the carrier 54, is to be moved out of the press, as described above in connection with the movable bolstemof FIGURE 1, fluid under pressure is supplied by any convenientmeans known to the art to passages 126- to raise sections 120to the level of the

tracks

50 and 52. Motor 96 is energized to drive the carriers until the wheels 74 of carrier 56 are positioned over the track sections 120. In this position of the parts, the carrier is approximatelypositioned to be secured to the press bed and the upper die 118 is likewise approximately positioned to be. secured to the drawing slide 22. It is necessary, however, that the carrier be accurately positioned before the parts are secured for press operation. After the carrier has thus been approximately positioned, the fluid is exhausted from cylinders 124 to permit pistons 122 to be drivendownwardlyin their cylinders under the influence of the weight of the carrier and die set. When this isaccomplished, the wheels 74 sink with the sections I until the carrier rests on the press bed 20. In the course of this movement, it the carrier isnot exactly positioned, the wheels 74 engage an edge of the respective discontinuities formed by movable track sections 1-20 and the carrier is shifted to the correct position. As can be seen by reference to FIGURES 3 and 8, I may employ locating buttons 123 formed on the bed 20" and adaptedto engage in recesses 125 formed in the bottom of carrier 56 or in the bottom of amovable bolster; It is to be understood that the length of a track discontinuity formed by a sectoin 120 is such that when the carrier is properly positioned, the entire weight of the carrier and die assembly is supported on the press bed and while the wheels 74 may engage track discon tinuity edges, the wheelssupport no weight; It is to be noted further that the connection provided by arms 78- and 80 andprojections 82 and 84 between the carriers 54 and 56, if employed, permits the carrier disposed over thepress bed to move downwardly when properly positioned on the bed.

Referring again to FIGURE 8, when the carrier is properly positioned, a number of clamps 132 extending over the flange 66 on the carrier are secured by bolts 134 to the press bed. Thus, the carrier and bolster 112 carried: by the carrier ring are held in position on the press bed 20. The movable bolsters of FIGURE 1 similarly are secured to the press bed.

Referring to FIGURES 2 and 9 to 11, the inner slide 22 supports anumber of drive motors 136. Each motor 136 drives a shaft 138 carrying a pinion 140 for rotation with it. Pinion-1140 drivesa gear 142, the hub 144 of which isrotatably carried on bushings 146 mounted on astub shaft 148 fixed in a housing 150 on the inner slide. I form hub 144 with a pinion 152 which engages a gear 154 rotatably supported in housing 150 on a hearing plate 156; A clamping bolt, indicated generally by the reference character 158 has a threaded shank 169 and a rectangular head 162. The end 164 of shank 160 remote from head 162 is reduced along a diameter to form a rectangular cross-sectional area, the major axis of which is at right angles; to the major axis of the crosssectional area of head 1 62. The threaded shank 160 of belt 158- is threaded into the threaded axial bore 166 of gear 154. End 164 is disposed in an opening 168 in the top of housing 150. I form opening 168 with a pair of stops I70 and 172 adapted to be engaged by end 164.

6 head 162' isdisposed to permit: its entry into the; slot 174. When the drawing slide 22 has been moved, as described. above, to insert head 162 through opening 174 and into a bore 179 on the upper die, the direction drive of motor 136 is reversed. In this direction of drive; of the motor, bolt 158 moves with gear 154 until thebolt: assumes the full-line position shown in FIGURES 9 and. 10; In this position of end 164, further rotation of bolt 158i with gear 154 is prevented. At the same time, the:

- major axis of head 162 is at right angles to the major axis of opening 174. Upon further rotation of gear 154, bolt 158 is drawn upwardly as viewed in FIGURE. 9 tosecure the upper die firmly to the inner slide. When it is desired to unclamp the upper die, the direction of drive of the motor 136 is reversed. In this direction of drive of the motor, the upper die is released and bolt 158 is drivenv to align head 162 with opening 174' to? permit withdrawal of inner slide 22 from the upper die- 1'18'. It is" to be understood that as many clamping bolts- 158 as are necessary to provide a firm engagement between the upper die and inner slide maybe employed. It will be seen thatbolts 158 provide a means for se-' curing the upper die to the. inner slide without the necessity of inserting a tool inside the blank holder slide.

Referring now to FIGURES l2 and 13, I have shown an alternate means for securing the upper die to the inner slide. In this form of my securing means, I' employ the same clamping bolts 158 as are shown in theform of my securing meansin FIGURES 9 to 11. I replace gear 154 with a worm gear 180 adapted to be driven by aworm 1 82. One end 184 of worm 182 is adapted to be engaged by an air operated tool to drive the worm to rotate gear 180' to secure the upper dietothe slide 22. opening 186 in the blank holder slide 24 provides access to worm end 184.

In operation of my: readily changeable die set assembly' for power presses; when the press is to be set up, fluid under pressure is supplied to cylinders 124 to raise the movable track sections 120 to the level of

tracks

50 and 52. A bolster such" asthe bolster 49, or a carrier such as carrier 54- carrying adie set is run along the tracks into the press over the press bed. When the. bolster carrying: the die set has been approximately positioned with respectto the movable track sections 120, fiuid is exhausted from cylinders 124 and the bolster and dies sink under the influence of gravity until they are supported on the press bed 20. In the course of. this; action, the bolster is not correctly positioned, wheels. 7-4 engage edges of the discontinuities formed. by the movable sections 120to shift the" bolster and die assembly' and die set to the correct position. When the bolster is correctly positioned, clamps 132 are assembled on the bed to hold the bolster and the lower die in position on the bed. The drawing slide 22 is lowered with the heads 162 of bolts 158" alignedwith openings 174 until the heads enter bores 179. Motors 136 then are driven to move ends 164 to the full-line position shown in FIG- URES' 9 and 10. Continued. rotation of. the motors 136' draws bolts 158' up to secure the upper die 118 firmly to the inner slide 22. Alternately to the form of the upper die clamping means shown in FIGURES 9 to II, the form; of clamping means shown in FIGURES 1'2 and 13 maybe employed. It: will be understood that if the press with which my die assembly is used includes no blank holder slide, common bolts may be used to secure the. upper die to the drawing slide. After the upper die 118 has been securedv to the drawing slide and the carrier ring 54 supporting a bolster 112. and lower die 117 or the movable bolster 49 supporting the lower die 117 has been secured to the press bed, the drawing slide may be moved upwardly to move the upper die. 118 away from. the lower die 117'. Inthe. course of this action the upper die 118. moves. away from. the. lower die. 117 along thein, FIGURES 9 and. 1.0. In. this position of end 164. guideposts 116..

"'When it is desired to change the press setup'from that corresponding, for example, to the die set carried by bolster 49 to that, for example, corresponding to the die set carried by bolster 51, bolts 158 are actuated to release the upper die from the inner slide and thebolster 49 is released from the press bed. Fluid under pressure is supplied to cylinders 124 to raise track sections 120 and bolster 54 and its die set. Motor 96 is energized to drive pinion 106 to move bolster 49 out of the press and advance bolster 51 into the press. Where unconnected bolsters are employed, these operations are performed separately. When bolster 51 is approximately positioned with its wheels 74 over sections 120, the fluid in cylinders 124 is exhausted and the bolster is properly located. The bolster and upper die may then be secured to the respective press bed and drawing slide as described hereinabove. The operation of the form of my invention including movable bolsters 49 and 51 shown in FIGURE 1 is thesame as that of the form of my invention including cartiers 54 and 56 shown in FIGURES 2 to 7.

; While I have shown and described an assembly including only two movable bolsters, it will be readily understood that a train of bolsters, each of which carries a different die set, may, if desired be employed. It is to be understood further that the die set on bolster 49 may be changed while bolster 51 is in use and vice versa.

It will be seen that I have accomplished the objects of my invention. I have provided a readily changeable die assembly for power presses by means of which the setup or a press may be changed in a rapid, convenient, and ei rpeditious manner. The setting-up operation with my assembly does not require the expensive labor involved in setting up a power press in the prior art. My assemblyincludes meansfor locating a die set accurately on the press bed. I provide my assembly with means for rapidly and simply securing the upper die of a die set to the press drawing slide. My assembly eliminates the need for employing a large number of presses where a great variety of short run parts are to be made; It does not require a manufacturer to make long runs of small demand parts in order to save setup labor cost. a It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is therefore to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. In a metal Working press having a bed, a crown, uprights between the bed and crown and a draw slide vertically movable toward and away from said bed,

mechanism for replacing die sets in said press compris-- ing, tracks on said bed arranged between opposed uprights and extending outwardly from opposite sides of the press, first and second longitudinally aligned bolsters arranged in end to end relationship and connected tog'ether at adjacent ends, wheels for supporting said first and second bolsters for movement on said tracks, means for moving said bolsters on the tracks into and out of the press, each bolster adapted to receive a die set thereon when outside of the press, said die sets including upper and lower dies, the lower die being secured tothe bolster when outside of the press and the upper surface of the upper die being adapted to be placed in abutting relationship with the lower surface of said draw slide when the bolster and die set have been positioned in the press, means within the press for locating the bolster at a predetermined position in the press, fluid pressure means in said press bed for moving the wheels between an upper position so that the bolster may move on said tracks and a lower position which lowers the bolster to the press bed prior to the forming operation to give the bolster a firm foundation during the press operation, clamping means in the press cooperable with longitudinal grooves formed in the sides of the bolster for clamping the bolster in its lowered position to the bed, and means for securing the upper die to the draw slide when the bolster and die set have been positioned in the press and the draw slide lowered to abutting relationship with said upper surface of the upper die.

2. A readily changeable die assembly for a power press having a frame and a bed and a working slide mounted in the frame for reciprocation with respect to the bed including in combination a movable member, dies carried by said member and comprising an upper die adapted to be secured to saidworking slide and a lower die adapted to be secured to said member, means supporting said member for movement from a location adjacent said press to a position within said press over and above said bed and means for locating said member on said bed in a located position to permit said upper die to be secured to said working slide, said supporting means including wheels carried by said member, rails carried by the bedof the press on which the wheels are adapted to rest, said rails being formed with a plurality of movable sections within said press, said wheels being adapted to rest on said movable sections when said member is in position within said press, a plurality of fluid pressure cylinder and piston assemblies, means for supporting said moveable rail sections on said piston and cylinder assemblies, means for actuating said piston and cylinder assemblies to lower said member in said located position to the pressbed prior to the reciprocation of the working slide.-

3. A quick die change power press including in commination a frame, a bed, a working slide mounted in; the frame for movement with respect to the bed, a bolster, a pair of coacting dies carried by said bolster and comprising an upper die adapted to be secured to the working slide and a lower die, means supporting the bolster above the bed for movement from a first location adjacent said press to a second location over the bed at which the upper die may be secured to the slide, means for moving the bolster from said first location to said second location, said supporting means and said bolster coacting to guide said bolster along a predetermined path on said supporting means in its movement from said first location to said second location, said supporting means comprising means adapted to be actuated to lower said bolster toward said bed at said second location and means for actuating said lowering means to lower said bolster in said second location prior to the operation of said slide.'

4. In a metal working press having a bed, a crown, uprights between thebed and crown and a slide vertically movable between the uprights, mechanism for easily and quickly replacing dies in said press thereby reducing press down time comprising, supporting means including tracks mounted on said bed and extending outwardly from opposite sides of the press and between opposed uprights, a bolster movable on said tracks, said bolster adapted to receive thereon a die set having upper and lower dies, means to secure the lower die of the die set to the bolster when the bolster is outside of the press, means for secur ing the upper die of the die set to the slide after the bolster has been positioned within the press, means for driving the bolster along the tracks and into the press with a die set thereon, said supporting means and said bolster coacting to guide said bolster along a predetermined path in the course of its movement into the press and locating means within the press including means on said bed coacting with means on the bolster for precisely locating the bolster at a predetermined position along the press bed beneath the slide, said supporting means including means operable for lowering the bolster into intimate engagement with the bed prior to press operation thereby giving it a firm foundation.

5. In a metal working press having a bed, a crown, uprights between the bed and crown and a slide vertical 1y movable between the uprights, mechanism for easily and quickly replacing dies in said press thereby reducing press down time comprising, supporting means including tracks mounted on said bed and extending outwardly from opposite sides of the press and between opposed uprights, a bolster movable on said tracks, said bolster adapted to receive thereon a die set having upper and lower dies, means for securing the uper die of the die set to the slide after the bolster has been positioned within the press, means for driving the bolster along the tracks and into the press with a die set thereon, said supporting means and said bolster coacting to guide said bolster along a predetermined path on said supporting means from a position outside the press to a position within the press above said bed and under said slide, locating means within the press including means on said bed coacting with means on the bolster for precisely locating the bolster at a predetermined position on the press bed beneath the slide, said supporting means comprising means for lowering the bolster to the bed into intimate engagement therewith prior to press operation thereby giving it a firm foundation, and means for securing the bolster to the bed thereby assuring stability during operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,607,073 Gros NOV. 16, 1926 1,607,074 Gros Nov. 16, 1926 2,186,799 iBoker Jan. 9, 1940 2,317,440 Cannon n Apr. 27, 1943 2,647,784 Janiszewski Aug. 4, 1953 2,765,836 Niekelski Oct. 9, 1956