US3495526A

US3495526A - Die try-out press

Info

Publication number: US3495526A
Application number: US697102A
Authority: US
Inventors: Forrest N Mohler; James E Davis
Original assignee: Dependable Tool and Die Co Inc
Current assignee: Dependable Tool and Die Co Inc
Priority date: 1968-01-11
Filing date: 1968-01-11
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17

Description

Feb. 11, 1910.. NMoHLER- AL 3,495,526

DjIE TRY-OUT rnmss I Filed Jan. 11. 1968 4 Sheets-Sheet 1 IN VENTORS Feb. 17, 1970 FJQVMOHLER'ETJAYL 3,495,525

mm TRY-OUT mass Y Filed Jan. 11, 1968 4 Sheets-Sheet 2 Y Mm M Feb. 17, 1970 F. N. MOHLER E AL mi: TRY-OUT rnnss 4 Sheets Sheet 3 Filed Jan. 11, 1968 UMHHHH H Ullmm r ///Vv/ ///A INVENTOR. Tana? 71.7mm y 4% 2 4100M, (Mew,- W 1' 7 5- I Fig 4- United States Patent O US. Cl. 10053 2 Claims ABSTRACT OF THE DISCLOSURE A press having a ram driven 'by a pair of hydraulic cylinders of large load capacity, and a bolster pivotable out from under the ram, for die accessability. Hydraulic cylinders and pistons for pivoting the bolster and for operating bolster locks. Ram guide bushings projecting toward the base rather than toward the crown for added rigidity.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to presses useful for trying out dies, and more particularly to a press having a tiltable bolster for accessability of a die section to the diemaker.

Description of the prior art:

Examples of prior art presses known to us are found in the following United States patents: 2,429,669, 2,602,- 508, 2,940,384, and 3,211,085.

There is also known a device referred to as a die handler offered by the Hansford Manufacturing Corp. of Rochester, NY.

In the manufacture of forming dies, spotting is necessary in order that the two halves can be properly matched to produce a part meeting speifications. It is typical practice to do this work with the die halves in a press. Although it is more convenient for a diemaker to work on one half of the die set for spotting-in purposes, it remains a difficult and hazardous operation, particularly on large dies. It necessitates the diemaker climbing into a press in some instances and Working under the ram.

In die try-out work, it is desirable to have complete control of the ram, to be able to move it smoothly, to be ably to apply full tonnage capacity at any point of the stroke, and to be assured of safe operation. Hydraulic operation of press rams has been employed in the past in an effort to achieve these objectives. Heretofore, however, this has necessitated construction of custom-built and necessarily expensive hydraulic pistons, cylinders, and associated details. Moreover, the self-equalizing characteristics of hydraulics, together with certain limitations in structural rigidity of units, has heretofore permitted misalignment errors to seriously affect spotting working on hydraulic driven die try-out presses.

The necessity for rigidity in try-out presses should be apparent, in view of the necessity of accuracy in spotting work. Typical approaches to attainment of rigidity are the addition of size and mass. Yet such additions are disadvantageous from most'every other standpoint.

Most of the above mentioned prior art has nothing to do with die manufacture itself. Accordingly it offers little or nothing useful as a solution to the aforementioned problems. The present invention does solve these problems, as will become apparent as this description proceeds.

SUMMARY Described briefly, in a typical embodiment of the present invention, a press is provided with a base having guide posts extending upwardly therefrom and supporting 3,495,526 Patented Feb. 17, 1970 a crown. A ram is slidingly received on the posts between the crown and a bolster, the bolster being pivotally mounted on the base so that the upper face thereof is movable from a position facing the ram to an angular position facing away from the ram.

The crown is mounted comparatively near the base, considering the available stroke and minimum shut position of the ram. This is made possible by extending the ram bearing sleeves downwardly rather than upwardly, thus enhancing rigidity of the structure.

BRIEF DESCRIPTION OF THE DRAWINGS The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is a front elevational view of one embodiment of this invention, with portions sectioned to show interior details.

FIG. 2 is a side elevational view thereof.

FIG. 3 is an enlarged fragmentary section taken at line 3-3 in FIG. 1 and viewed in the direction of the arrows showing the tilt cylinder and a slide lock cylinder.

FIG. 4 is a further enlarged fragmentary plan view of the slide lock and cylinder, taken at line 4-4 in FIG. 3.

FIG. 5 is a schematic diagram of the hydraulic control circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, and particularly FIGURES 1 and 2. thereof the illustrated embodiment of the present invention includes a base 11 with four cylindrical posts 12 affixed thereto and extending upwardly therefrom. A crown 13 is received on the upper ends of the posts and aflixed thereto by fasteners 14.

Two hydraulic cylinders 16 are afiixed to the crown and the piston rods 17 are connected to the ram 18 having a platen 19 with a flat lower face 21 appropriately grooved for attachment of half of a die set thereto. The platen has four bearing sleeves 26 thereon, each having bushings therein slidingly received on one of the four posts 12, as will be described more fully hereinafter.

In the illustrated embodiment of the invention, the base is a rigid assembly of a plurality of weldments. Two of these provide trunnion boxes at 27 rigidly secured in horizontally spaced relationship to each other by large front and rear channel members 28. Gussets are provided along these channels for additional rigidity, and other gussets of various shapes are provided throughout the structure for additional rigidity where desired.

The tninnion boxes are provided to implement the pivotable bolster feature of the invention. The bolster 29 includes a pair of legs 31, each having a trunnion 32 aflixed thereto near the lower end thereof and received in bearings 33 secured in one of the trunnion boxes. The bolster is thereby pivotable about the axis 34 from the position shown by the solid outline wherein the upper face 36 of the bolster platen faces the lower face 21 of the ram platen, to the position shown by the dotted outline wherein the surface 36 faces away from the ram platen face. In addition to the radial load bearings 33 in each trunnion box, a suitable spacer 37 and thrust bearing 38 is provided between each of the bolster legs and the trunnion box associated therewith.

As shown in FIGURE 2, a stop block 39 is aifixed to the base at the rear thereof and the upper face 41 thereof abuttingly engages the lower face of the holster at 42 to locate the bolster plate face 36 parallel to the ram face 21 when the ram is to be moved vertically downward and upward on the posts 12.

At the front of the bolster are two stop blocks 43 aflixed to the bolster plate at 44. The lower ends 4 6 of these blocks abuttingly engage upper faces 47 of slide blocks 48 which are solidly supported in a vertical direction on an upper surface 49 of the base assembly. Accordingly these slide blocks 48 serve as stop blocks to prevent tilting of the bolster away from the position shown by the solid outlines in FIGURES 1 and 2. However they are slidable in the direction of the arrow 52 when desired in order to permit tilting outward of the bolster in a manner which will be described hereinafter.

To accommodate the outward tilting of the bolster, each slide block 48 has a hydraulic cylinder 53 associated therewith and mounted to the base assembly. The piston rod of the cylinder is connected to the slide block pulling it toward the rear of the base assembly out of the way of the upper stop block 43 associated therewith.

To tilt the bolster, one of the bolster legs has a bracket 54 afiixed thereto and pinned at 56 to the end of the piston rod 57 of a hydraulic cylinder 58. The hydraulic cylinder is pinned to the base assembly at 59.

In the description to this point, it has been mentioned that hydraulic cylinder and piston assemblies are provided for ram action, bolster tilting, and bolster locking. Other types of motors might also be used within the scope of the invention, but hydraulic motors as described are believed preferable.

Referring now to the hydraulic circuit diagram, wherein one example of a control circuit is illustrated, the pump 61' draws hydraulic fluid from the reservoir 62 and supplies it on line 63 at a pressure (normally less than 1,000 p.s.i.) to the valve 64. A return line is provided at 66 from valve 64 to the tank. Valve 64 is a closed-center, three-position, four-way hydraulic control valve such as a Logan No. 7032, for example. In the illustrated example, it is operable to an up or down position by actuation of the manual lever 67. The supply and return lines from the valve 64 are connected through valve 68 and speed control valves 69 to the ram drive cylinders. Valve 68 is typically a two-position, four-way pilot operated spring return hydraulic control valve such as Logan No. 4151, for example. The speed control valves 69 may be Logan No. 8115, for example.

Because of the closed-center position of valve 64, the piston in the ram drive cylinder 16 can neither move up or down. However, upon pushing the manual lever 67 to the down position, for example, pump supply through line 63, passageway 71 of valve 64, passageway 72 of valve 68, speed control 69 to the junction 73 and from there to the upper ends of both cylinder 16 is provided. This causes the ram to move downwardly. Upon return to center by valve 64, the ram is stopped. Upon movement of the lever 67 to up position, hydraulic fluid is supplied to the lower ends of the ram drive cylinder through passageway 74 of valve 64, passageway 76 of volve 68 and the other flow control valve 69 to junction 77.

Note that for valve 68 there is an operator button 78 engaged by a bolster leg at 79 to hold the valve in the position shown when the bolster is in press operating position shown by the solid outlines in FIGURES 1 and 2. However the moment the bolster moves from this position, the spring 80 on valve 68 shifts it to block both hydraulic lines and prevent movement of the ram regardless of the position of the ram control lever 67. In this way there is assurance that the ram will not operate unless the bolster is in the proper position.

Referring further to the hydraulic schematic diagram, hydraulic supply to the bolster tilt cylinder 58 and bolster lock cylinders 53 is provided through the threeposition, closed-center, four-way hydraulic control valve 81, which may be like valve 64. The manual operator 82 for this valve is movable between one position to move the bolster out from under the ram, and another position to move the bolster back into position under the ram. From valve 81, the supply is through valve 83 which m y be a two-posit on, four=way cam-operated spring return hydraulic control valve such as Logan No. 6095, for example. This valve is normally maintained in the position shown by the ram 13 engaging the cam operator 84 for the valve when the ram is fully up. Speed control valves 86 may be provided in the lines to and from the cylinders and an example is the Logan No. 8015 adjustable hydraulic speed control valve.

With valve 81 in its closed-center position, no supply to or return from the bolster tilting cylinder and bolster lock cylinders is possible. Upon moving the knob 82 to the out position, and assuming that the ram is fully up, hydraulic fluid is supplied from line '63 through passageway 87 of valve 81, passageway 88 of valve 83 and one of the speed control valves 86 to the rod-side of the pistons in the bolster lock cylinders to retract the slide blocks. Meanwhile hydraulic fluid is applied at a restricted rate through the adjustable valve portion 89 of valve assembly 91 to the cylinder head end of the piston in the tilt cylinder 58. Extension of the piston rod thereof in the direction of arrow 92 begins to tilt out the bolster. The opposite or rod-end of the piston displaces hydraulic fluid through the return line to the tank. Similarly, when the pressure was applied to the rod-end of the pistons in the bolster lock cylinders, hydraulic fluid was displaced from the other end through the check valve 94 to the return lines. By provision of the adjustable restriction 89, there is time for the bolster lock slides to be retracted before the outward movement of the bolster occurs.

To return the bolster to its original press-operating position, facing the ram, the knob 82 is placed in the in position whereupon the supply is through passageway 96 of

valve

81, 97 of valve 83 and one of the speed control valves 86 to the rod-end of the tilt cylinder 58 initiating retraction of the bolster. At a rate suitably reduced by the adjustable restriction 98, the bolster lock slides are returned to their original position, arriving there slightly after the bolster has returned to its press-operating position. The

valve assemblies

91 and 101 may be adjustable by-pass and check valves (sequencing) such as Logan No. 9030, for example.

By providing the aforementioned tilt-out feature of the bolster, the diemaker can do this spotting work on the die half afiixed to the bolster, without the necessity of climbing and without the necessity of moving between the ram and the bolster.

In the discussion of prior art problems, the importance of rigidity was mentioned. The reason for this is the fact that in the initial steps of trying out the die on the press, the halves do not match. Therefore, upon application of even minor loads used in spotting work, lateral and angular deflection loads can be high. In an elffort to minimize angular deflections, it is customary to provide a substantial length between the upper and lower bearings of ram guide bearings on the posts, depending to some extent on the overall width of the bolster or press bed. For example, a bearing height of one-half the bed length can be used. Conventional practice is to extend the bearing tubes upward from a line lying in or near the plane of the lower face of the ram platen. The result is that the guide posts are quite high, necessitating large overall press heights for a given stroke and shut height, tending to reduce the rigidity desired. It is another feature of the present invention to overcome this problem and this is done by projecting the bearing tubes well below the plane of the ram platen face. For example, the lower bearing circuit 101 of the lower bushing 102 is 18 inches below the lower face 21 of the ram platen in one example of the press according to the present invention. This particular example of press has a 14 inch stroke from the position shown by the solid outline to the position shown by the dotted outline, providing a shut height between the upper face 36 of the bolster platen and the lower face 19 of the ram platen at its lowermost position, of 10 inches. At this point, the lower end bearings are well below the plane of the bolster platen face as indicated at 1018, being immediately adjacent the location of attachment at 103 of the guide posts with the trunnion boxes of the base assembly. Therefore, when the press is shut, an entirely adequate overall bearing height is provided and yet by -virtue of this construction, the crown can be located much closed to the bolster than with constructions heretofore used. In this example, the bolster platen is 57 inches wide from the right-hand edge 104 to the left-hand edge 106. The post diameters are inches and the length of each of the lower bushings and each of the upper bushings 107 is 4 inches. These are merely examples, the important feature being the extension of the bearings substantially beyond the plane of the ram platen face toward the base assembly.

The stop blocks described above prevent tipping of the 'bolster on its pivots during press operation for spotting purposes. Axial thrust hearings on the trunnions are provided and correct axial location is assured during press operation by provision of bolster guide blocks 108 on the top of the trunnion box and having wear plates 109 thereon engaging the bolster bearing blocks 111 aflixed to the outward faces of the bolster legs.

It is believed that the above description together with the drawing are sufficient to enable anyone skilled in the art to build a spotting press having optimum utility and representing a substantial advance in the art. In the illustrated example, the ram drive cylinders are typically 8 inch hydraulic cylinders with 3 /2 inch diameter rods and 14 inch stroke. The tilt cylinder maybe a 3% inch diameter cylinder with 6 /2 inch stroke. The lock slide cylinders are typically 1% inch diameter cylinders with 2 /2 inch stroke. In each event, the piston is cushioned at both ends.

The invention claimed is:

1. A press comprising:

a base;

a ram reciprocable with respect to said base;

a bolster in a first position facing said ram and pivotally mounted to said base for pivotal movement from said first position to a second position facing away from said ram;

first hydraulic motor means coupled to said ram and to said base and operable to reciprocate said ram with respect to said base; and

control means for said first motor means, including a first valve operable in a first position to supply hydraulic fluid in a first line to said first motor means to shut the press, said first valve being operable in a second position to supply hydraulic fluid in a second line to said first motor means to open the press, said control means including a second valve responsive to position of said bolster and operable when said bolster is in said first position thereof to accommodate the said supply of hydraulic fluid to said first motor means, said second valve being operable in response to movement of said bolster away from said first position thereof to prevent said supply of hydraulic fluid to said first motor means.

2. A press comprising:

a base;

a ram reciprocable with respect to said base;

first motor means coupled to said ram and to said base and operable to reciprocate said ram with respect to said base;

second motor means coupled to said base and to said bolster and operable to pivot said bolster between said first and second positions;

stop means on said base and said bolster and interengageable to prevent movement of said bolster away from said first position; and

third motor means coupled to said base and to one of said stop means and operable to move said one stop means into position preventing movement of said bolster away from said first position.

References Cited UNITED STATES PATENTS BILLY J. WILHITE, Primary Examiner US. Cl. X.R.