Die lifter device for a press brake

Abstract

A die lifter device 10 for a press brake includes a die lifting roller 12 for engaging a bottom wall 14 of a die 16 disposed in a modified die holder member 18 of a press brake, a roller support member 20 for disposing the roller 12 at a predetermined position relative to the modified die holder member 18, a cam bolt 22 for adjusting the elevation of the roller 12 relative to the modified die holder member 18, vertical and horizontal recesses 24 and 28 disposed in the modified die holder member 18 for removably receiving cooperating components of the die lifter device 10 such that the roller 12 is ultimately positioned above a top wall 26 of the modified die holder member 18 to allow the die 16 to be rolled off the modified die holder member 18 after the die 16 has configured a workpiece. The roller 12 is then positioned below the top wall 26 of the modified die holder member 18 to allow another die 16 to be disposed upon the top wall 26 without damaging the die lifter device 10.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to die lifting devices and more particularly, to a die lifting device for a press brake that allows an operator to slide a die off a die holder member of the press brake when the operator urges a roller to forcibly elevate the die above the die holder member, the operator then lowers the roller bellow a top wall of the die holder member, whereupon, another die is disposed upon the die holder member.

2. Background of the Prior Art

Press brakes are used in fabrication shops to forcibly bend a workpiece such as metal strips or sheets into predetermined configurations. The configurations result from the design of a die forcibly engaging and bending the workpiece. The die is disposed in a die holder member of the press brake. The press brake imparts, via the die, a great amount of force upon a workpiece to bend or otherwise shape the workpiece into the desired configuration. The imparted force requires the die to be staunchly constructed and fabricated from heavy steel resulting in a die that is very difficult to remove from the die holder member by an operator. Die removal techniques utilized by operators include but are not limited to hoists, fork trucks and multiple operators to physically lift the die.

Prior art die removal devices include rollers and bearings permanently encased in housings that are disposed upon the die holder member such that the rollers or bearings have an exposed fixed position. The problem with permanently positioning the rollers or bearing above a support housing is that the rollers or bearings are susceptible to being damaged or otherwise made inoperable when the heavy die is placed or in some cases dropped upon the die holder member. Examples of fixed position prior art rollers and bearings for die removal from a press include products manufactured by Carrlane Press Brake Tools and Flowtek limited, models DB, DL and DS.

A need exists for a die lifter device that is manually retractable such that the rollers or bearings that engage the die are ultimately lowered below a die receiving top wall of the die holder member before the die is set upon the top wall. Also, a need exits for a die lifter device that is manually operated to elevate the die above the die holder member thereby allowing the die to be horizontally slide of the die holder member by only one operator. Further, a need exist for a die lifter device with internal force dampening components that prevent the roller and cooperating components from being damaged should an operator cause the roller to be elevated to quickly when engaging a bottom wall of the die, or should the operator forget to lower the roller after removing the die and before forcibly setting a new die upon the exposed roller.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome many of the disadvantages associated with a die lifter device.

A principle object of the present invention is to provide a die lifter device that is removably received by a typical die holder member. A feature of the device is components that are cylindrically configured. An advantage of the device is that it is easily combined with a die holder member by simply boring vertical and horizontal recesses into predetermined portions of the die holder member; the recesses snugly and removably receive corresponding members of the die lifter device.

Another object of the present invention is to lower a die lifting roller below the top wall of a die holder member modified to receive the die lifter device. A feature of the device is a cam bolt having a cam portion with a planar wall that removably receives a retainer member thereupon such that when the planar wall is horizontal, the retainer member causes the die lifting roller to be disposed below the top wall of the now modified die holder member. An advantage of the device is that the die lifting roller is prevented from being damaged when a die is set upon the top wall of the modified holder member.

Yet another object of the present invention is to raise the die lifting roller above the top wall of the modified die holder member when a die has completed a predetermined job and must be removed from the modified die holder member. A feature of the device is that the cam bolt is allowed to rotate to vertically position the planar wall thereby elevating the retainer member and correspondingly elevating the die lifting roller such that the roller is above the top wall of the modified die holder member. An advantage of the device is that the die is elevated above the top wall of the modified die holder member to allow the die to horizontally slide off the modified die holder member, whereupon, the die lifting roller is lowered below the top wall and another die is placed upon the die holder member.

Still another object of the present invention is to dampen vertical impact between cooperating components of the device that ultimately elevate the die above the modified die holder member. A feature of the device is a plurality of vertically aligned concave washers. An advantage of the device is that excessive lifting force generated by an operator forcefully rotating the cam bolt, is reduced to a magnitude that prevents the die lifting roller and/or a roller support member from being damaged when the roller engages a bottom wall of the die.

Another object of the present invention is to allow an user to easily operate the device. A feature of the device is a recess in a drive portion of the cam bolt. An advantage of the device is that a standard hand tool is utilized to allow the user to rotate the cam bolt to elevate the die lifting roller and ultimately remove the die from the modified die holder member.

Another object of the present invention is to dispose the roller such that the roller shaft axis is perpendicular to a central longitudinal recess in the modified die holder member, and such that the roller ultimately engages a central portion of a die protuberance that inserts into the central longitudinal recess. A feature of the device is a vertical recess centrally disposed in the central longitudinal recess. Another feature of the device is a horizontal recess disposed in a side wall of the modified die holder member, the horizontal recess perpendicularly intersecting the vertical recess. An advantage of the device is that the surface of the roller uniformly engages a bottom wall of the die protuberance when the roller elevates the die.

Another object of the present invention is to prevent the rotation of the roller support member inside the vertical recess in the modified die holder member while allowing the roller support member to move vertically relative to the cam bolt. A feature of the device is a saddle shaped recess in a bottom portion of the roller support member; the recess including edge portions that engage the cylindrical periphery of the cam bolt. An advantage of the device is that the roller support member will not rotate inside the vertical recess when the cam bolt elevates the roller support member thereby maintaining the roller shaft axis perpendicular with the central longitudinal recess in the modified die holder member resulting in the roller rotating in the same direction that the die is ultimately pushed when being removed from the die holder member.

Briefly, the invention provides a die lifter device for a press brake comprising a roller for engaging a lower surface or wall of a die disposed upon a modified die holder member of a press brake; a roller support member for disposing said roller at a predetermined position relative to the modified die holder member; a cam bolt for adjusting the elevation of said roller relative to the press brake; and means for removably receiving said roller, roller support member and cam bolt in predetermined portions of the die holder member of the press brake whereby a portion of said roller is ultimately positioned above a die engagement wall of the die holder member to elevate the die from the die holder member to allow the die to be rolled off the die holder member after the die has configured a workpiece.

The invention further provides a device for elevating a die above a modified die holder member of a press brake to allow the die to be rolled off the modified die holder member comprising at least one roller disposed at a predetermined portion of the modified die holder member; means for securing the horizontal position of said roller; means for elevating said securing means such that a portion of said roller is ultimately disposed above a top wall of the modified die holder member; and means for rotating said elevating means whereby the vertical position of said roller is varied such that a first position of said roller is above the top wall of the modified die holder member, and a second position of said roller is below the top wall of the modified die holder member.

The invention further provides a method for elevating a die above a modified die holder member of a press brake to allow the die to be rolled off the modified die holder member, said method comprising the steps of inserting at least one roller at a predetermined portion of the modified die holder member; securing the horizontal position of said roller relative to the modified die holder member; providing means for vertically altering the position of said roller relative to the modified die holder member; and providing means for receiving and transferring rotary motion such that the vertical positioning means are altered to dispose said roller below a top wall of the modified die holder member or to dispose said roller above the top wall of the modified die holder member such that the die is ultimately elevated above the modified die holder member thereby allowing the die to be rolled off the modified die holder member.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and novel features of the present invention, as well as details of an illustrative embodiment thereof, will be more fully understood from the following detailed description and attached drawings, wherein:

FIG. 1 is a perspective view of a die lifter device in accordance with the present invention.

FIG. 2 is an exploded perspective view of the die lifter device of FIG. 1.

FIG. 3 is an exploded perspective view of a die lifter device inserted in a typical die holder member that has been modified to removably receive the die lifter device.

FIG. 4 is a front phantom view of FIG. 3, but with a typical die disposed upon the top wall of the modified die holder and with the die lifter device disposed in a non-lifting position such that a die lifting roller (depicted in a phantom view) is disposed below the top wall of the modified die holder member.

FIG. 5 is the front phantom view of FIG. 4, but with the die lifter device disposed in a lifting position such that the die lifting roller is disposed above the top wall of the modified die holder member thereby elevating the die to allow the die to be horizontally urged from the modified die holder member.

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2 depicting the die lifter device in a non-lifting position.

FIG. 7 is the sectional view of FIG. 6 but with the die lifter device depicted in a die lifting position.

FIG. 8 is a side sectional view of the die lifter device in a non-lifting position taken along line 8-8 of FIG. 4.

FIG. 9 is a side sectional view of the die lifter device in a lifting position taken along line 9-9 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and in particular to FIGS. 1-5, a die lifter device for a press brake is denoted by numeral 10. The device 10 includes a die lifting roller 12 for engaging a bottom wall 14 of a die 16 (not part of the invention) disposed upon a modified die holder member 18 of a press brake (not depicted). The device 10 further includes a roller support member 20 for disposing the roller 12 at a predetermined position relative to the modified die holder 18, a cam bolt 22 for adjusting the elevation of the roller 12 relative to the press brake, a vertical recess 24 in a top wall 26 of the modified die holder 18 for removably receiving the roller 12 and roller support member 20, and a horizontal recess 28 in a side wall 30 of the modified die holder member 18 for removably receiving the cam bolt 22. The vertical and horizontal recesses 24 and 28 are cooperatively disposed to facilitate the engagement of the roller support member 20 with a cam portion 32 of the cam bolt 22 whereby a portion or all of the roller 12 is ultimately positioned above the top wall 26 of the modified die holder member 18 to elevate the die above the modified die holder member 18 to allow the die 16 to be rolled off the modified die holder member 18 after the die 16 has configured a workpiece (not depicted).

To reduce or dampen a lifting force imparted from the cam bolt 22 to the roller support member 20, a resilient member 34 is cooperatively disposed relative to the roller support member 20 and the cam bolt 22 thereby preventing damage and excessive wear to portions of the cam bolt 22 that forcibly engage corresponding portions of the roller support member 20. The resilient member 34 may include metal springs, arcuate washers or similar “shock absorbers” well known to those of ordinary skill in the art. The preferred embodiment is a plurality of arcuate washers 34 manufactured by Bellville, Inc. and others. The washers 34 are disposed upon a retainer member 36 such that a bottom surface 38 of the retainer member 36 engages the cam portion 32 of the cam bolt 22, and a top surface 40 of a top arcuate washer 42 engages a cooperating portion of the roller support member 20. The washers 34 are orientated such that concave center portions 44 are all positioned in an upward direction thereby providing a force dampening feature that protects the roller 12, roller support member 20 and cam bolt 22 when the cam bolt 22 is rotated to forcibly urge the retainer member 36, washers 42 and roller support member 20 vertically until the roller 12 elevates the die 16 above the modified die holder member 18. Besides preventing damage, the washers 34 allow an operator of the device 10 to increase or lower the vertical elevation of the roller 12 relative to the modified die holder member 18 thus allowing one device 10 to be vertically dimensioned for use among multiple modified die holder members 18 by simply removing or adding one or more washers 34.

The roller support member 20 includes a top portion 46 having a top recess 48 configured and dimensioned to allow the roller 12 to insert therein such that the roller 12 is free to rotate when supported by a shaft or axle 50 forcibly inserted into opposing apertures 52 disposed adjacent to a top wall 54 of the top portion 46. The top portion 46 includes a roller aperture 49 that facilitates the installation of a roller with an “oversized” diameter that would otherwise engage a bottom wall 51 of the top portion 46. The larger roller 12 promotes increased elevation of the die 16 above the modified die holder member 18, which is required when dirt, grease or other foreign matter accumulates on the top wall 26 of the modified die holder member 18. The roller 12 is orientated such that the axis of the roller 12 is transverse to the longitudinal axis of the die 16 thereby allowing the roller 12 to rotate in the same direction as the die 16 when the die 16 is ultimately urged off the modified die holder member 18.

The roller support member 20 further includes a bottom portion 55 having a bottom recess 56 configured and dimensioned to removably receive the plurality of concave washers 44, retainer member 36 and cam portion 32 of the cam bolt 22 thereby maintaining the vertical alignment of the retainer member 36 and washers 44 upon the cam bolt 22 irrespective of the radial position of the cam bolt 22 when elevating or lowering the roller 12 relative to the modified die holder member 18. The bottom recess 56 is offset or radially displaced from the top recess 48 ninety degrees such that the diametric passage of the recess 56 through the support member 20 is parallel with the longitudinal axis of the axle 50. Offsetting the top and bottom recesses 48 and 56 orientates the shaft 50 and axis of the roller 12 transverse to both the longitudinal axis of the die 16 and the longitudinal axis of the cam bolt 22 thereby allowing the roller 12 to rotate in the same direction as the die 16 when the die is ultimately urged or pushed off the modified die holder member 18.

The bottom recess 56 has a “saddle” configuration and includes vertical edge portions 57 distally separated by an arcuate horizontal edge portion 59 a predetermined distance that disposes the vertical edge portions 57 adjacent to without engaging the cylindrical periphery of the cam bolt 22. The bottom recess 56 configuration promotes the encasing of the cam bolt 22 to prevent the rotation of the roller support member 20 inside a vertical recess in the modified die holder member 18 while allowing the roller support member 20 to move vertically relative to the cam bolt 22. Thus, the roller shaft 50 axis is maintained substantially perpendicular to the central longitudinal axis of the modified die holder member 18 when elevating the roller 12 to lift the die 16 thereby promoting a roller 12 rotation that is parallel to the horizontal direction that the die is pushed when removing the die 16 from the modified die holder member 18. If the direction of rotation of the roller 12 was not parallel with die 16 movement, the roller 12 would impede the horizontal movement of the die 16 resulting in damage to the roller 12 and/or other members of the device 10.

The top surface 40 of the top washer 42 continually engages a top wall 58 of the bottom recess 56 irrespective of the position of the cam portion 32 of the cam bolt 22 thereby elevating the roller 12 when the cam bolt 22 is rotated such that an edge portion 60 and corresponding cylindrical wall of the bolt 22 engage the bottom surface 38 of the retainer member 36 which forcibly compresses the washers 34 ultimately forcing the top washer 42 against the top wall 58 and lifting the roller support member 20 until the die 16 is elevated a predetermined distance above the modified die holder member 18. The cam bolt 22 rotates via cylindrically configured first and second support portions 62 and 64 engaging cooperating portions of the modified die holder member 18. The cam bolt 22 is forcibly rotated via a wrench or similar drive tool inserted into a congruently configured recess 66 disposed in a central portion of a drive portion 68 and integrally joined to the first support portion 62 of the cam bolt 22. The longitudinal position of the cam bolt 22 is substantially maintained by a threaded retaining portion 70 integrally joined to the second support portion 64 of the cam bolt 22. The threaded retaining portion 70 engages corresponding threads in a cooperating recess in the modified die holder member 18.

Referring now to FIGS. 1 and 2, the roller 12 includes a knurled outer raceway 72 that promotes roller 12 rotation via engagement with the elevated horizontally moving die 16, and reduces wear between an inner raceway 74 of the roller 12 and a central portion of the shaft 50 that the inner raceway 74 rotates upon. Should the die 16 slide upon the roller 12 instead of rotating the roller 12, the shaft or axle 50 would eventually erode a portion of the inner raceway 74 of the roller 12 causing premature device 10 failure even with the addition of a grease lubricant.

Referring now to FIG. 1, 2, and 6-9, the cam bolt 22 is cylindrically configured with the cam portion 32 disposed at a longitudinal mid-portion of the cam bolt 22. The cam portion 32 includes a hemispherical recess 76 (see FIG. 2 ), and is longitudinally dimensioned to unobstructedly receive the bottom surface 38 of the retainer member 36 upon a planar wall 78. When the planar wall 78 is horizontally disposed, the roller 12 is positioned below the planar top wall 26 of the modified die holder member 18. In the horizontal position, the planar wall 78 congruently engages a cooperating portion of the bottom surface 38 of the retainer member 36. As the cam bolt 22 is rotated to vertically elevate the roller 12, a relatively small portion of the planar wall 78 engages the bottom surface 38. When the planar wall 78 is vertically disposed, the roller 12 is positioned above the top wall 26 of the modified die holder member 18 thereby elevating the die 16 via the roller 12 forcibly urging the bottom wall 14 of the die 16 in a vertical direction. In the vertical position, the planar wall 78 does not engage the bottom surface 38, but the edge portion 60 of the wall 78 together with a corresponding cylindrical portion of the cam bolt 22 does engage the bottom surface 38 of the retainer member 36.

Referring now to FIG. 2, the retainer member 36 includes a washer configured lower portion 80 and a cylinder configured upper portion 82. The upper and lower portions 80 and 82 have respective diameters dimensioned to provide a washer engagement wall 84 that cooperates with the axial dimension of the upper portion 80 and a lateral dimension of the bottom recess 56 in the bottom portion 55 of the roller support member 20 to substantially maintain the axial or vertical positions of the arcuate washers 34 during operation of the device 10.

Referring now to FIGS. 2-5, 8 and 9, the device 10 is installed in a typical die holder member by boring a substantially cylindrical, vertical recess 86 in the top wall 26 of the die holder member, and a substantially cylindrical, horizontal recess 88 in a side wall 90 of the die holder member. The vertical recess 86 removably receives the roller 12, roller support member 20 and the plurality of arcuate washers 34. The vertical recess 86 is configured and dimensioned to snugly receive the roller support member 20 thereby maintaining the horizontal position of the roller 12. The horizontal recess 88 removably receives the cam bolt 22. The horizontal recess 88 is configured and dimensioned to snugly receive all portions of the cam bolt 22 thereby cooperating with the threaded retaining portion 70 of the cam bolt 22 to substantially secure and maintain the horizontal position of the cam bolt 22 relative to the now modified die holder member 18 while allowing the cam bolt 22 to rotate. Maintaining the horizontal positions of the roller support member 20 and the cam bolt 22, disposes the roller 12 such that the roller shaft 50 axis is perpendicular to a central longitudinal axis of the die thereby promoting uniform engagement between the bottom of the die and the roller 12 to minimize friction and device 10 damage when the die is elevated. The vertical and horizontal recesses 86 and 88 are cooperatively disposed to facilitate the insertion of the cam portion 32 of the cam bolt 22 into the bottom recess 56 of the bottom portion 54 of the roller support member such that the bottom surface 38 of the retainer member 36 engages the planar wall 78 of the cam portion 32 of the cam bolt 22. One or more vertical recesses 86 are disposed along the longitudinal centerline of the top wall 26 of the modified die holder member 18.

Some die holder members include a central longitudinal recess 92 that removably receives a central longitudinal protuberance 94 of the die 16 to maintain the position of the die 16 relative to the die holder member. A modified die holder member 18 with the central longitudinal recess 92 would include a vertical recess 86 disposed in a preselected portion of the central recess 92 such that the roller 12 engages the protuberance 94 and vertically elevates the die 16 sufficiently to horizontally slide the die 16 from the modified die holder member 18 while maintaining a substantial portion of the protuberance 94 within the central recess 92 to prevent the protuberance 94 from “jumping” out of the central recess 92 while horizontally sliding the die 16.

In operation, a die holder member of a press brake is modified to removably receive a die lifter device 10 for every three feet of longitudinal length. The die holder member is modified by boring vertical recesses 86 along a longitudinal centerline of the top wall 26 of the die holder member. Horizontal recesses 88 are bored in a side wall 30 of the die holder member such that the longitudinal axes of the vertical and horizontal recesses 86 and 88 perpendicularly intersect. The horizontal recesses 88 are disposed a predetermined distance below the top wall 26 that corresponds to the longitudinal dimension of the device 10 whereby the bottom surface 38 of the retainer member 36 congruently engages a horizontally disposed cam portion 32 of the cam bolt 22 which positions the roller 12 below the surface of the top wall 26 of the now modified die holder member 18.

A preselected die 16 is placed upon the top wall 26 of the modified die holder member 18 with the planar wall 78 of the cam portion 32 in a horizontal position and the roller 12 correspondingly disposed at a position below the top wall 26. When a replacement die 16 is required, an operator rotates the cam bolt 22 via a tool inserted in the recess 66 such that the planar wall of the cam portion 32 slowly forces the retainer member 36 vertically upward thereby compressing the washers 34 against the bottom portion 55 of the roller support member 20 and forcing the roller 12 against the bottom wall 14 of the die 16 until the roller 12 is forcibly positioned above the top wall 26 of the modified die holder member 18 resulting in the die 16 being elevated above the modified die holder member 18. Once elevated, the die 16 is horizontally slide upon the rollers 12 and removed from the modified die holder member 18. Once the die 16 is removed from the modified die holder member 18, the cam bolt 22 is rotated in either direction until the bottom surface 38 of the retainer member engages the planar wall 78 of the cam portion 32 of the cam bolt 22 thereby lowering the roller 12 below the top wall 26 and allowing the modified die holder member 18 to receive another die 16.

The foregoing description is for purposes of illustration only and is not intended to limit the scope of protection accorded this invention. The scope of protection is to be measured by the following claims, which should be interpreted as broadly as the inventive contribution permits.

Claims

1. A die lifter device for a press brake comprising:

a roller for engaging a lower surface of a die disposed upon a modified die holder member of a press brake;

a roller support member for disposing said roller at a predetermined position relative to the modified die holder member;

a cam bolt for adjusting the elevation of said roller relative to the press brake; and

means for removably receiving said roller, roller support member and cam bolt in predetermined portions of the die holder member of the press brake whereby a portion of said roller is ultimately positioned above a die engagement wall of the die holder member to elevate the die from the die holder member to allow the die to be rolled off the die holder member after the die has configured a workpiece.

2. The die lifter device of claim 1 wherein a resilient member is cooperatively disposed relative to said roller support member and said cam bolt such that when operating said die lifter device, a lifting force imparted from said cam bolt to said roller support member is dampened.

3. The die lifter device of claim 2 wherein said resilient member includes a plurality of arcuate washers disposed upon a retainer member such that a bottom surface of said retainer member engages a cooperating portion of said cam bolt, and a top surface of a top arcuate washer engages a cooperating portion of said roller support member.

4. The die lifter device of claim 1 wherein said roller includes a shaft axially disposed through said roller, said shaft being forcibly retained in a top portion of said roller support member via opposing apertures.

5. The die lifter device of claim 4 wherein said shaft disposes an outer raceway of said roller above a top surface of said roller support member while allowing an inner raceway of said roller to rotate upon a central portion of said shaft whereby a die is ultimately elevated above a die holder and moved in a horizontal direction that is transverse to the axis of said shaft.

6. The die lifter device of claim 1 wherein said roller support member includes an upper recess that is configured to allow said roller to rotate therein without obstruction.

7. The die lifter device of claim 1 wherein said roller support member includes a lower recess that is configured to cooperatively receive a predetermined portion of said cam bolt.

8. The die lifter device of claim 3 wherein said roller support member includes a lower recess that is configured to cooperatively receive said plurality of arcuate washers and said retainer member.

9. The die lifter device of claim 1 wherein said cam bolt includes a cam portion disposed between opposing first and second support portions, a drive portion integrally joined to said first support portion and a retaining portion integrally joined to said second support portion.

10. The die lifter device of claim 9 wherein said drive portion includes means for removably receiving a tool that rotates said cam bolt.

11. The die lifter device of claim 9 wherein said retaining portion is threaded to engage a cooperating portion of the modified die holder member.

12. The die lifter device of claim 1 wherein said cam bolt is cylindrically configured.

13. The die lifter device of claim 9 wherein said cam portion includes a recess having a planar portion for cooperatively receiving as lower recess of said roller support member.

14. The die lifter device of claim 9 wherein said cam portion includes a recess having a planar portion for cooperatively receiving a bottom planar surface of a retaining member.

15. The die lifter device of claim 3 wherein said retainer member includes a washer configured lower portion and a cylinder configured upper portion, said lower and upper portions having respective diameters dimensioned to provide a washer engagement wall that cooperates with the axial dimension of the upper portion and a lateral dimension of a lower portion of said roller support member to substantially maintain the axial positions of said plurality of arcuate washers.

16. The die lifter device of claim 1 wherein said roller includes a knurled die engagement surface.

17. The die lifter device of claim 1 wherein said removable receiving means includes a vertical recess in a top wall of the die holder member, said vertical recess removably receiving said roller and roller support member; and a horizontal recess in a side wall of the modified die holder member, said horizontal recess removably receiving said cam bolt, said vertical and horizontal recesses being cooperatively disposed to facilitate the engagement of said roller support member with a cam portion of said cam bolt.

18. The die lifter device of claim 1 wherein said removably receiving means includes a vertical recess in a top wall of the die holder member, said vertical recess removably receiving said roller, said roller support member and a plurality of arcuate washers, and a horizontal recess in a side wall of the modified die holder member, said horizontal recess removably receiving said cam bolt, said vertical and horizontal recesses being cooperatively disposed to facilitate the engagement of a bottom surface of a retainer member with a cam portion of said cam bolt.

19. The die lifter device of claim 17 wherein said vertical recess is disposed in a central longitudinal recess in the modified die holder member.

20. A device for elevating a die above a modified die holder member of a press brake to allow the die to be rolled off the die holder member comprising:

at least one roller disposed at a predetermined portion of the modified die holder member;

means for securing the horizontal position of said roller;

means for elevating said securing means such that a portion of said roller is ultimately disposed above a top wall of the modified die holder member; and

means for rotating said elevating means whereby the vertical position of said roller is varied such that a first position of said roller is above the top wall of the modified die holder member, and a second position of said roller is below the top wall of the modified die holder member.

21. A method for elevating a modified die above a modified die holder member of a press brake to allow the die to be rolled off the modified die holder member, said method comprising the steps of:

inserting at least one roller at a predetermined portion of the modified die holder member;

securing the horizontal position of said roller relative to the modified die holder member;

providing means for vertically altering the position of said roller relative to the modified die holder member; and

providing means for receiving and transferring rotary motion such that the vertical positioning means are altered to dispose said roller below a top wall of the modified die holder member or to dispose said roller above the top wall of the modified die holder member such that the die is ultimately elevated above the modified die holder member thereby allowing the die to be rolled off the modified die holder member.