Rollingly transportable press die apparatus

A die structure for use in conjunction with a metal working press is provided without the usual large bottom plate member secured to the undersides of the spaced apart parallel members projecting downwardly from the underside of the shoe portion of the die. To permit the plateless die structure to be rollingly transported from place to place along a horizontal support surface, a plurality of specially designed lifter devices are secured to the die parallels and rotatably carry a plurality of roller members. The lifter devices are pneumatically operable and, when actuated, drive the roller members downwardly beyond the common plane in which the bottom sides of the parallels lie to thereby elevate the die structure above a horizontal support surface and rollingly support the die structure thereon. Upon deactivation thereof, the lifter devices permit the undersides of the die parallels to settle back down onto the support surface, thereby stationarily positioning the plateless die structure thereon.

BACKGROUND OF THE INVENTION 
The present invention relates generally to die structures used in 
conjunction with metal working presses, and more particularly relates to 
methods and apparatus for transporting a die structure to and from a metal 
working press. 
In conventional metal stamping operations, selected portions of a sheet of 
metal are punched out and removed utilizing a punch die structure 
removably interconnected to the opposed bed and vertically movable ram 
portions of a metal working press. The typical prior art punch die 
includes an upper die section positioned above a die shoe and connected to 
the shoe, for vertical movement relative thereto, by leader pin members. 
Projecting downwardly from the underside of the die shoe are two or more 
spaced apart, parallel support base members, usually referred to in the 
press art simply as "parallels". With the punch die operatively connected 
to the press, the metal-forming operation is carried out by positioning 
the metal sheet atop the die shoe and then downwardly moving the press ram 
to drive the upper die section into engagement with the metal sheet. 
Since a conventional punch die typically weighs between 1,000 and 10,000 
pounds or more, it is understandably difficult to move from its storage 
location to the press and back again after its use. To facilitate the 
transport of the die structure it has been conventional practice to attach 
a large metal base plate to the underside of the die parallels. During 
storage of the overall die structure, the base plate is supported atop the 
upper side surface of a storage platform into which liftable roller 
structures are recessed To move the die to its associated press, a 
specially designed die cart is used, the die cart having similarly 
recessed, liftable roller structures on its top side surface. 
When the die is to be used, the cart is rolled up to the die storage 
platform, and the recessed roller structures of both the platform and the 
cart are elevated so that the die can be rolled along the raised platform 
surface rollers onto the raised rollers of the cart. The cart rollers are 
then lowered so that the base plate of the die rests directly on the flat 
top surface of the cart. After this is done, the cart is rolled to the 
punch press adjacent the press bed which is conventionally provided with 
liftable roller structures recessed into its top surface. 
To transfer the die onto the press bed, the cart and press bed rollers are 
raised, and the die is rolled off the cart and onto the elevated bed 
rollers which are then lowered so that the bottom die support plate rests 
upon the flat upper surface of the press bed. Finally, the upper and lower 
die sections are respectively anchored to the press ram and the press bed 
to ready the press for operation. 
As can readily be imagined, this previous necessity of providing recessed, 
liftably roller systems in die storage platforms, die carts and press beds 
to facilitate die changeout undesirably adds considerable expense and 
complexity to the overall punch press operation and requires that all 
three of these structures be of a customized construction. Additionally, 
the requirement for the large base plate secured to the undersides of the 
die parallels adds considerable weight and expense to each individual die 
structure and can undesirably add to the time and expense associated with 
routine maintenance thereof. 
Various proposals have been made in the prior art to eliminate the 
necessity for providing recessed roller structures in the die storage 
platforms, the die transport cart, and the press bed by utilizing 
die-supporting structures, referred to as bolsters or carriages, which 
basically comprise a platform having wheels or rollers operatively secured 
to its underside. The bottom plate of a die structure is suitably anchored 
to the top of the bolster or carriage platform, and the platform wheels 
are positioned in tracks which lead to and from the press bed. To load a 
particular bed onto its associated press, the bolster is simply wheeled 
along the tracks until the bolster-supported die is operatively positioned 
on the press bed. The die and its bolster are then suitably clamped in 
place on the press bed. 
A variety of structures are provided for lowering the underside of the 
bolster platform onto the top side of the press bed. For example, portions 
of the track sections extending across the press bed may be selectively 
lowered as representatively shown in U.S. Pat. No. 3,422,660 to Countess, 
Jr. et al and U.S. Pat. No. 3,986,448 to Seyfried et al. Alternatively, 
the bolster wheels may be spring-biased downwardly from the bolster 
platform, and the bolster platform subsequently clamped downwardly to 
overcome the wheel spring force, as illustrated in U.S Pat. No. 3,456,481 
to Zeitlin. 
U.S. Pat. No. 4,301,673 to Yonezawa discloses downwardly recessed wheels in 
the top of a bolster platform which may be raised to facilitate the 
rolling onto and off of the bolster platform of the die structure which it 
supports. Other disclosures of wheeled die bolster structures are present 
in U.S. Pat. No. 2,996,025 to Georgeff, and U.S. Pat. Nos. 3,229,791 and 
3,306,185 to Soman. 
A number of prior art bolsters, having platforms to which the bottom die 
plate is fixedly secured, are provided with vertically movable wheel 
structures as alternatives to collapsible track sections and the like to 
permit the bolster platform to be lowered onto and raised upwardly from 
the press bed top surface. For example, U.S. Pat. No. 3,422,662 to Geuss 
discloses a wheeled, die-supporting bolster secured to the underside of a 
die set. Lowerable sets of wheels are provided in side edge grooves of the 
bolster platform and are lowerable by fluid cylinders, via pivotable 
brackets, to elevate the bottom side of the bolster platform. Separate 
lifting jack mechanisms are provided in the press bed to lift the bolster 
platform before its wheels are lowered. U.S. Pat. No. 3,368,479 to 
Gregorovich illustrates liftably bolster wheels which are actuated by a 
motor and gear system. U.S. Pat. No. 4,528,903 to Lerch discloses a 
die-supporting bolster/carriage provided with wheels that are 
pneumatically liftable and lowerable relative to the bolster platform via 
the operation of pistons received in cylinders formed in the bolster 
platform. 
While the use of these and other wheeled bolster devices to facilitate die 
transport arguably represents improvements over recessed wheel or roller 
structures provided in die storage platforms, die carts and press beds, 
they still present various disadvantages in the overall transport of die 
structures to and from their associated presses. For example, all of the 
above-described wheeled bolster devices require the presence on the die 
structure which they support of the conventional large bottom plate. 
Additionally, the wheeled bolster devices referred to above add 
considerable weight, height, and expense to the die structures to which 
they are secured. Further, the wheel lifting structures provided on these 
conventional bolster and carriage devices are of a rather complex 
construction. 
It can readily be seen from the foregoing that a need exists for improved 
apparatus, operable to rollingly transport a punch die to and from its 
associated press, which eliminates or at least substantially reduces the 
above-mentioned problems, limitations, and disadvantages associated with 
conventional rolling die transport apparatus of the general type 
described. It is accordingly an object of the present invention to provide 
such improved apparatus. 
SUMMARY OF THE INVENTION 
In carrying out principles of the present invention, in accordance with a 
preferred embodiment thereof, an improved, rollingly transportable die 
structure is provided for use in conjunction with a metal working press 
having a bed portion disposed beneath a vertically movable ram portion. 
The die structure has a lower portion securable to the press bed and 
defined by a generally rectangular die shoe having a bottom side from 
which a spaced plurality of parallel support members (referred to in the 
press art simply as "parallels") downwardly project, the parallels having 
bottom side surfaces lying generally in a common plane. An upper die 
section, securable to the press ram, is secured above the die shoe, for 
vertical movement relative thereto, by a plurality of conventional leader 
pin members. 
According to a feature of the present invention, the die structure is not 
provided with the conventional large bottom plate normally anchored to the 
undersides of the parallels in punch press dies of this general type and 
utilized to secure the die atop a wheeled bolster, or to provide a base 
for the die to support it atop liftable rollers recessed in various 
horizontal support surfaces along which the die is to be moved. To provide 
for the improved rolling transport of the die structure along a particular 
horizontal support surface, a plurality of specially designed lifter means 
are secured to the lower die portion above the common plane of the bottom 
sides of the die parallels. 
The lifter means are vertically movable relative to the lower die portion 
between first and second positions. In their first position the lifter 
means permit the bottom side surfaces of the die parallel members to rest 
upon a horizontal support surface, thereby stationarily supporting the die 
structure thereon. When moved from their first position to their second 
position, the lifter means are operative to rollingly engage the 
horizontal support surface, while elevating the bottom side surfaces of 
the die parallels relative thereto, to permit the die structure to be 
rolled along the support surface until the lifter means are moved back to 
their aforementioned first position. In a preferred embodiment thereof, 
the lifter means are pressurizable (using, for example, compressed air 
from a source thereof) to drive them to their second position and are 
operative, when depressurized, to permit the weight of the die structure 
to return them to their first position. 
Each of the plurality of lifter means preferably comprises an upper member 
anchored to the lower die portion, and a lower member secured to the 
underside of the upper member for limited vertical movement relative 
thereto. The lower member has a plurality of rollers rotatably secured 
thereto and having bottom side surfaces spaced downwardly apart from the 
underside of the bottom member. 
Internal passage means are formed in the upper members and communicate with 
the upper ends of vertical cylinder bores formed therein and opening 
outwardly through the bottom sides of the upper members. Pistons are 
slidably received in the cylinder bores for vertical movement therein, and 
the internal passage means are connected to an air supply manifold system 
secured to the lower die portion and adapted to receive, via an 
appropriate quick disconnect fitting, compressed air from a source 
thereof. 
When the top ends of the cylinder bores are pressurized, their associated 
pistons are driven downwardly, engage the lower members, and drive the 
lower members downwardly to lower limit positions thereof to accordingly 
drive the lifter means to the aforementioned second position thereof. When 
the cylinder bores are depressurized, the weight of the die structure 
drives the lower members upwardly to an upper position thereof, thereby 
returning the lifter means to the aforementioned first position thereof.

DETAILED DESCRIPTION 
Illustrated in FIGS. and 2 is an improved die structure 10 which 
incorporates principles of the present invention and is usable in 
conjunction with a conventional metal-working punch press 12 having an 
elevated, horizontal bed surface 14 disposed beneath a vertically movable 
ram portion 16 of the press. The die structure 10 is representatively 
illustrated in FIG. 1 as being positioned atop the flat upper end surface 
18 of a conventional wheeled die cart 20 which may be rolled along the 
illustrated floor 22 toward and away from the press 12. In a unique manner 
subsequently described, the die structure 10 may be rolled from the cart 
support surface 18 onto the press bed 14, and back onto the cart surface 
18, without the conventional use of liftable roller structures recessed 
into the surfaces 14, 18 and without the use of wheeled bolster or 
carriage devices anchored to the underside of the die structure. 
As depicted in FIGS. 1, 2, and 5, the die structure 10 has a lower portion 
which includes a conventionally configured rectangular die shoe 24 from 
whose underside a plurality of spaced apart, parallel support members 
26.sub.a -26.sub.d downwardly project. The members 26.sub.a -26.sub.d are 
commonly referred to in the press art simply as "parallels" and have 
bottom side surfaces 28 lying in a common plane. In a conventional manner, 
the die structure 10 is provided with a rectangular upper die section 30 
which is positioned above and parallel to the die shoe 24. The upper die 
section 30 is connected to the die shoe 24 by means of four leader pin 
members 32 which, as indicated by the double-ended arrow 34 in FIG. 5, 
permit the upper die section to be moved vertically toward and away from 
the die shoe 24. 
When the die structure 10 is operatively positioned on the press bed 14, 
the lower die portion is suitably secured to the press bed, and the upper 
die section 30 is suitably anchored to the press ram 16 for vertical 
movement thereby toward and away from the die shoe. In the usual manner, 
with the upper die section 30 in an elevated position, a sheet of metal to 
be formed is placed on the upper side of the die shoe 24, and the ram 16 
is moved downwardly to cause the upper die section 30 to engage the metal 
sheet and cooperate with the die shoe 24 to appropriately deform the metal 
sheet or punch out selected portions thereof. 
It should be noted at the outset that, unlike punch press dies of 
conventional construction, the die structure 10 is not provided with the 
usual large rectangular bottom plate which is customarily anchored to the 
undersides 28 of the parallels 26.sub.a -26.sub.d. Accordingly, the die 
structure 10 will be hereinafter referred to as a "plateless" die 
structure The unique absence of the aforementioned bottom plate permits 
the bottom sides 28 of the die parallels to be rested directly upon a 
support surface, such as the top cart surface 18 shown in FIG. 2, to 
stationarily position the die structure on such support surface. 
Referring now to FIGS. 2 and 3, the plateless die structure 10 is rollingly 
transportable along a particular horizontal support surface by means of a 
very compact lifting system which is secured to the lower die portion, 
above the common plane of the bottom parallel sides 28, and forms an 
important aspect of the present invention. The lifting system 
representatively includes four pneumatically operable lifter assemblies 
40, two of which are secured to the outer side surface of the die parallel 
26.sub.a, and two of which are secured to the outer side surface of the 
die parallel 26.sub.d. 
As cross-sectionally indicated in FIG. 3, each of the lifter assemblies 40 
includes an upper rectangular metal block 42 which is anchored to its 
associated die parallel 26 by fastening members such as bolts 44. 
Extending horizontally through an upper portion of the block 42, between 
its opposite left and right ends, is a circularly cross-sectioned air flow 
passage 46 having vertical branch passages 48 that communicate with top 
ends of a pair of circular cylinder bores 50 which open outwardly at their 
lower ends through the bottom side surface 52 of the upper block 42. A 
pair of pistons 54 are slidably disposed within the bores 50, for vertical 
movement therein, and are provided with appropriate annular peripheral 
sliding seal elements 56. 
Each of the lifter assemblies 40 also includes a rectangular lower metal 
block member 58 disposed beneath the upper block member 42. The lower 
block member 58 is secured to the underside of block 42 by means of 
conventional shoulder bolts 60 which permit vertical movement of the lower 
block 58 relative to the upper block 52 between an unactuated, upper limit 
position (FIG. 3) in which the upper side 62 of the lower block 58 abuts 
the bottom side 52 of the upper block 42, and an actuated, lower limit 
position (FIG. 4) in which the lower block 58 is positioned downwardly 
apart from the upper block 42. Three horizontally spaced apart slots 64 
extend vertically through the lower block 58 from its upper side 62 to its 
lower side 66. Three cylindrical roller members 68 are journaled within 
the slots 64 on shafts 70 and, as indicated in FIGS. 3 and 4, have bottom 
side portions which project downwardly beyond the bottom side 66 of the 
lower block 58. 
Referring now to FIG. 2, the horizontal interior passages 46 in the four 
upper blocks 42 are intercommunicated by an air supply manifold system 
which includes two rectangular metal manifold block members 72.sub.a, 
72.sub.b secured to the right end of the die shoe 24, and two rectangular 
metal manifold block members 72.sub.c, 72.sub.d secured to the left end of 
the die shoe 24. The manifold blocks are interconnected as shown by three 
horizontal lengths of air supply tubing 74, the interiors of which are 
communicated by means of internal passages 76 formed in the blocks 
72.sub.a, 72.sub.b, and 72.sub.c. As illustrated in FIG. 2, the four 
manifold blocks project outwardly beyond the tubing lengths 74 which 
interconnect them, with the blocks 72.sub.b and 72.sub.c projecting 
rightwardly beyond the rear side 24.sub.a of the die shoe 24. Accordingly, 
the four manifold blocks provide a degree of protection for the tubing 
lengths 74 against impact during handling of the die structure 10 A quick 
disconnect air fitting 78 is secured to the left end of the manifold block 
72.sub.a and communicates with its internal passage 76 
The tubing length 74 interconnected between the manifold blocks 72.sub.c, 
72.sub.d is communicated with the internal passages 46 of the left pair of 
lifter assemblies 40 by branch tubing 80, while the tubing length 74 
interconnected between manifold blocks 72.sub.a, 72.sub.b is communicated 
with the interior passages 46 of the right pair of lifter assemblies 40 by 
branch tubing 82. Each of the tubing branch sections 80, 82 is connected 
to one end of its two associated upper block passages 46, with the 
opposite end of each of the four internal block passages 46 being closed 
with a suitable plug member 84 as indicated in FIGS. 3 and 4. 
Via the manifolded air supply system just described, the upper ends of all 
of the upper block cylinder bores 50 may be simultaneously pressurized 
simply by removably securing a pressurized air supply hose 86 (FIG 1) to 
the quick disconnect fitting 78. In the absence of such pressurization, 
the weight of the die structure 10 drives the lower block members 58 
upwardly to their unactuated, upper limit positions shown in FIG. 3, at 
which point the lower sides 28 of the die parallels 26.sub.a -26.sub.d 
settle down onto the support surface 18, thereby stationarily positioning 
the die structure 10 on the support surface 18. The upper and lower block 
portions 42, 58 of each lifter assembly 40 are relatively dimensioned and 
positioned on their associated die parallel such that when the lower block 
members 58 are moved upwardly to the unactuated positions, the lower sides 
of the roller members 68 are flush with the common plane of the bottom die 
parallel sides 28 as shown in FIG. 3, thereby effectively rendering the 
roller members 68 inoperative. 
However, when the upper ends of the cylinder bores 50 are simultaneously 
pressurized, the pistons 54 (FIG. 4) are driven downwardly through the 
open lower ends of the bores 50 and engage their associated lower block 
members 58 and drive them downwardly to their actuated, lower limit 
positions shown in FIG. 4. This causes the roller members 68 to be driven 
downwardly past the lower sides of the die parallels, forcibly engage the 
support surface 18, and lift the entire die structure 10 upwardly from the 
support surface 18. 
The lowered roller members 68, which have now lifted the die structure 10, 
also now support the elevated die structure for rolling movement along the 
support surface 18. When it is desired to again stationarily position the 
die structure 10 on its associated horizontal support surface, the air 
supply hose 86 is simply removed from the quick disconnect fitting 78, 
thereby allowing the cylinder bores 50 to depressurize and permitting the 
bottom sides 28 of the die parallels to settle back onto the support 
surface as illustrated in FIG. 3. 
The use of the small lifter assemblies 40 on the plateless die structure 10 
permits it to be very easily and rapidly moved from its storage platform 
to the press bed 14 and then back to its storage platform again when 
required. Specifically, with the lifter assemblies 40 in their 
unpressurized states, and the bottom sides 28 of the die parallels resting 
upon the die storage platform, the lifter assemblies are simply 
pressurized to lower the roller member 68 as described above. The die 
structure is then rolled off its support platform and onto the top surface 
18 of the conventional die cart 20. The lifter assemblies are then 
depressurized to allow the die structure to settle down onto the cart 
surface 18. The cart 20 is then rolled along the floor 22 into close 
adjacency with the press 12 as shown in FIG. The air supply hose 86 is 
then re-connected to the quick disconnect fitting 78 to again elevate the 
die structure 10 which is then simply rolled onto the press bed 14. The 
air supply hose 86 is then removed from the quick disconnect fitting 78 to 
permit the die structure 10 to settle down onto the press bed 14. Finally, 
the upper die section 30 is appropriately secured to the ram 16, and the 
lower die portion is appropriately secured to the press bed 14 to ready 
the now operatively positioned die structure 10 for its metal forming 
task. 
To return the die structure 10 to its storage location, the die structure 
is disconnected from the press bed 14 and the ram 16, pneumatically raised 
as previously described, rolled onto the top side 18 of the die cart 20 
and then re-lowered. The lowered die structure 10 is then rolled to its 
storage location on the cart 20, pneumatically raised, rolled off the cart 
20 onto the die storage platform, and then re-lowered. 
It can readily be seen from the foregoing that the use of the lifter 
assemblies 40 totally eliminates the previous necessity of securing a 
large bottom plate to the undersides of the die parallels 26, eliminates 
the previous necessity of securing a wheeled bolster or carriage to the 
underside of the bottom plate, and eliminates the previous necessity of 
providing the die storage platform, the cart 20, and the press bed 14 with 
liftable roller structures recessed into their upper side surfaces. This 
significantly simplifies and reduces the overall cost involved in 
rollingly transporting the die structure from place to place. The 
elimination of the customary die bottom plate, and the use of the lifter 
assemblies 40, also significantly reduces both the overall weight of the 
die structure and its maximum height. The elimination of the bottom die 
plate also facilitates the normal maintenance of the die structure. 
A number of modifications could be made to the illustrated die structure 
lifting system. For example, the pistons 54 could be incorporated in the 
lower blocks 58, and bear upwardly against the upper block 42, instead of 
being disposed within the upper block 42 and bearing downwardly against 
the lower block 58. Additionally, pressurized fluids other than air could 
be utilized to provide the die structure lifting force if desired. 
Another modification that could be made to the illustrated die structure 
lifting system would be to replace the illustrated four lifting assemblies 
with two lifting assemblies (one each on the die parallels 26.sub.a and 
26.sub.d) in which the upper and lower blocks 42 and 58 were longer in the 
left-to-right direction as viewed in FIG. 2. While it is particularly 
convenient, from an access standpoint, to secure the lifter assemblies 40 
to the outer side surfaces of the die parallels 26.sub.a and 26.sub.d as 
shown in FIG. 2, it will be appreciated that the lifter assemblies could 
be secured to alternate locations on the lower die portion. For example, 
as shown in phantom in FIG. 5, the lifter assemblies 40 could be secured 
to the inner side surfaces of the die parallels 26.sub.a, 26.sub.d (or to 
side surfaces of the parallels 26.sub.b, 26.sub.c), or secured to the 
underside of the die shoe 24 between adjacent pairs of die parallels. 
The foregoing detailed description is to be clearly understood as being 
given by way of illustration and example only, the spirit and scope of the 
present invention being limited solely by the appended claims.