CA1049922A - Cutoff die - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A modular cutoff die unit features square-ended punch and die steels, which are supported by and sized relative to their respective retaining shoes such as to provide four re-versable cutting edges and to allow plural cutoff dies to be arranged in tandem.

Description

~0499ZZ
The present in~ntion iB di~scted to~ard~ a modular cuto~ dle unltJ which is particularly adapted to pro-vide a "cutting ofr" cspability ~or magnetio punch holder and die holder assemblies o~ the type dis¢losed rOr instance in U.S~ Patents 3,o89,376 and 3,782,166.
In an illustrated rorm o~ the pre~ent invention, the modular cutoff die unit comprises a punch blade-retaining shoe position~lly located by a conventional punah templet and held against ~ punch shoe by magnetic means: a punch steel or blade removably rlxed to the punoh blade-retaining shoe; a dle blade-retaining shoe positionally located by a conventional die templet and supported by a die shoe; a die steel or blade re-movably fixed to the die blade-retalning shoe; and a pres~er-~oot assembly, whi¢h is mounted on the punch blade-retaining shoe and 15 coopsrate~ with the die blade~retaining shoe to positionally olamp.a workpieoe during a ¢utting operatlon.
~ partioularly lmportant reature o~ the present invention is that the punch and die steels, which may be inter-changeable, are shaped and supported relative to their assooiated 20 ~ shoes such as to provide ~our reversable autting edges~ which may be resharpened without neces~itatlng ohange o~ re~erenoe spaoing between the punch and die shoo~.
A further ~eature of the pre~ent unit is its modular construction and the square-end deslgn Or the punoh and die steels, which enable units to be arranged in tandem to form an overall cutting edge whose length is a multiple Or the length Or each punch and die steel, While a pre~ently proposed commercial ~orm Or the present modular cutor~ die unit will be hereinarter described in detail, it is antioipated that the novel reatures Or the

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-3 -present invention may be incorporated within ¢uto~r die U~lt8 of otherwi~c div~rse constructlon.
The nature and mode o~ oper~tion o~ the present in~ention wlll now be more ~ully described ln the ~ollowlng de-tailed descrlption taken with the aooompanying drawingS wherein' FI~. 1 is a side elev~tional view o~ a die setmounting a modular cuto~f die unit ~ormed in acaordance with the present invention;
: FIG. 2 i~ an enlarged vlew o~ the modular.outor~
die unit shown in Fig. 1~ but with parts broken away ~or purpose Or ¢larlty;
FIGS. 3 and 4 are sectional views taken generally along the lines ~-3 and 4~ in Fig. 1~ and further illustrating punch and die units, respectively, arranged in tandem; and FIG. 5 i8 a sectional vie~ taken genèrally along the line 5-5 in Fig. 3.
Reference is first made to Fig. i, wherein a conventional die set is generally designated a~ 10 and shown as mounting therewithin a modular ¢utof~ dle unit, which is ~ormed in accordance with the present invention and generally designated as 12. A workpiece, such as a piece of sheet metal~ on which a cutting operation is to be per~ormed, is generally de~ignated at : Die qet 10 i~ qhown in F~g. 1 a~ generally in-cluding a punch shoe 16~ which i9 adapted to be suitQbly seoured to a pre~s ram, not shown; a die shoe 18, which is adapted to be suitably ~e¢ured to a pre~s bolster, also not ~hown;.a plurality o~ shoe guide a~semblies 20~ whioh lnclude Q die shoe mounted guide post 22 and a punoh shoe mounted guide post receiving bushing 24; a punch templet 26, which is adapted to be releas-ably secured to punch shoe 16 by a plurality of templet support

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or locator posts 28; and a die templet 30, which 19 adapted to be removably ~ecured to dle shoe lB by a plurality of templet ~upport or locator posts 32. A more complete description Or the ¢onstruction Or die set 10 may be had by rererence to U.S.
Patents 3,o8~J376 and 3~782,166 .

In Figs. 2_4~ templets 26 and 30 are speci~ically shown h9 being formed with locator holes 26a and 30a and clear-ance openings 26b and 30b~ which are ~ized~ shaped and arranged 10 to accommodate a plurality of identically sized modular cutor~
die units 12 arranged in tandem. Howe~Ter) it will be understood that the speciric design o~ the~e templets will vary wlth press setup requirements~ that ~9~ the number and relatlve size or cutting lengths or the modular cutofr die ~its to be employed 15 and whether ~dditional operations, suoh as per~oratlng~ notching~
embossing, lan¢lng, formlng, }cnock-out, stamping~ etc. ar.e to be simultaneously per~ormed on workpiece 14.
By ~riewing Flgs. 1-4, it will be understood that eaoh modular cutoff die unlt 12 includes a pair Or asso¢iated 20 punch and die units 40 and 42~ which are adapted to be suitably . affixed to racing surraces 16a and 18a Or punch and die shoes 16 and lô, respectively, such that they are arranged in operative vertical registration in order to e~ect ~cutting~ofr Or work-piece 14, whenever punch shoe 16 i9 cau~ed to reciprocate be-25 twe~n it~ upper or die set open position shown in Fig. 1 andits low~r or die set closed po~ition shown in Fig. 2.
~` Punch and die units 40 and 42 are similar in many resp~cts, Thererore~ in order to ~impliry the ~ollowing description Or the ¢on~tr~ctlon of unit 12~ only punch unit 40 30 will be rully described ln particular detail and the elements sur~aces 64, and mounting openln~ 70 are ~r~anged one-half on eaoh side Or the locator bore openlng with the positio~al re-lation~hip of each hal~ o~ such mountlng openings relati~e to the locator bore openin~ being ldentical~
Retainer shoe 46 i~ shown as being in the form of a metal casting adapted to be removably rixed or suspended ~rom the downwardly ~acing surrace 16a o~ punch ~hoe 16 by means o~ magnet device~ 73, which may be o~ the type discloqed for in~qtance in U.S. Patents 3~o89,376 and 3,~82,166~ and to be horizontally positionally looated within die set 10 to pro~ect downwardly through the temperate plate clearance openlng 26b by means of locator po~ts 74 releasably locked within temperate locator openings 26a by ~nap rings 76. In that the ~oroe of gravity tends to malntain die retainer ~hoe 46l in bearing en-gagement with the upwardly ~aaing sur~ace 18a Or die shoe 18jit is normally not neoe~sary to provide the die retainer shoe with magnet devices o~ the type described above... While the illustrated means ror attaching and positionally locating retainer shoes 46 and 46t i~ pre~erred, it will be understood that any other ~uitable mean~ may be employed.
By now mak~ng re~erence to Figs. 2 and 3, it will be seen that retainer shoe 46 is shaped to derine a horizontally elongated and vertically di~po3ed retainer clamping 9ur~ace 78;
a retainer bearing surfaoe 80, which extend~ horizontally and in a right angular relation~qhip from ad~acent one marginal edge o~
surrace 78; and a retainer clearance ~urface 82, which extends ~rom ad~acent an opposite and parallel marginal edge o~ qur~ace 78 ln a direction away ~rom retainer bearlng surface 80. Pre~er-ably, the lengthwise direotion o~ retainer ~hoe 46, a~ measured horizontally and ler~thwise o~ s~r~aces 78 and 80 be~ween opposlte 1~4~92Z

o~ dle unit 42~ which ar~ o~ slmilar con~tructlon~ wlll be de~ignated ln the drawings by like primed numerals. ~ore ~peci-rically, punch unit 40 i9 similar to dle unit 42 in that it generally inaludes an elongated ~eel or blade 44; a retainer

5 shoe 46; and mean~ in the f orm o~ a locator pin 48 and a plur-ality Or bo~ts 50 for removably cla~nping and positlonally orienting ~teel 44 relative to retainer ~hoe 46. Punch unit 40 prlncipally dirrer~ ~rom p~ch unit 42 in that lts retainer shoe 46 19 shaped to accommodate a workpiece presser~oot lO assembly 52, whereas the latter has its retalner shoe 46~ shaped to provide a ~upport rib 54, which is formed with openings 55 ~or af~ording access to bolts 50 and de~ines a ~upport sur~ace 56 arranged to oooperate with its assoclated steel 44- to pro-vide a support ~or workpieoe 14 in the manner best shown ~n 15 Figs. and 2.
Re~erence is now made particularly to Figs. 2,, 3 and 5, wherein steel 4~ hown as being ~ormed ~rom a rec~
tangular bar stock having squared ends, such that lt assumes a reotangular paralleleplped configuration having parallel 20 clamping or ~irst sur~aces 60~ parallel bearing or second sur ~aces 62 and parallel end or third sur~aces 64. Sur~aces 60 and 62 cooperate at thelr ~unctures to define ~our cutting or shear edees 66a-66d, which extend lengthwise of the steel be--tween end surfaces 64. Steel 44 ig pre~erably provided with a 25 plurality o~ mounting bore openings 70 and a single locator bore opening 72, which oollecbively open through clamping sur~a¢es 60 and have their ~xes arranged in parallel and to lie within a ¢ommon plane arranged equidi~tant ~rom bearing sur~aoes 62.
Moreover~ ag wlll be apparent rrom viewing Fig. ~, locator 0 bore openin8 72 is pre~erably dispo~ed equidi~tant from end ends of the retalner sho~3~ whlch are designated ~s 46a and 46b, i3 less than the lengthwlse dlmen~ion o~ steel 44, ag meaqured between end sur~aces 64. Further~ the widthvrlse or vertical dimension of retainer olamping surraoe 78 i9 sub3tantially 5 less than the widthwise dimension o~ clamping surraces 60, a3 measured between bearlng surraoes 62, Thu~, when steel 44 i3 ~ixed to retainer shoe 46 in the manner to be desoribed~ the ends of the steel may be arranged to pro~ect outwardly beyond oppo3ite end~ 46a and 46b~ and olamping ~ur~ace 60, whioh en-..
lO gages with retainer clamping qur~aoe 78J ha~ a portion thereo~
designated a~ 60a arranged to pro~ect beyond retainer clearance 82.
Retainer shoe 46 i8 al30 ~ormed with a plurality Or threaded openings 84 and a ~lngle looator reoeiving opening 15 86, which 19 pre~erably dispo~ed equidistant ~rom end sur~aoes l~6a and 46b. Openlngs 84 and 86 oollectlvely apen through clamping surIaces 78 and have their aXes disposed in a parallel relationship and to lie within a common planeJ v~hioh is arranged parallel to retainer bearing sur~aoe 80 and spaced thererrom 20 through a diqtance oorresponding to a ~pacing between looator reoei~ring bore opening 72 of steel 44 and steel bearing sur-~aces 62.
Retalner shoe 46 is additionally ~ormed with a plurality o~ stepped diameter bore mountlng openings 88,. whioh 25 are arranged ln a parallel spaoed relation3hip and open down-wardly through retainer clearance sur~ace 82 in the manner best shown in ~ig3. 2 and 3. By rererring spe¢i~ically to Fig. 2, it wlll be understood that each o~ mountlng openings 88 lnoludes an enlarged dlameter upper portlon 88a, an enlarged diameter 30 lower portion 88b and a reduoed diameter central or oonneoting --7i .

portion 88c, which cooperate to de~lne upwardly and downwardly facing annular Qhoulders or abutment surfaces 88d and 88c dis-posed concentrically o~ sentral portion 88c.
Locator p~n 48 is best shown in Fig~. 3 and 5 5 as having a cylindrioally shaped end portion 48al which is sized to be snugly recei~ed within lo¢ator receiving opening 86~
and an opposite, "non-round" end portion 48b, which 1~ sized to.
be slidably received withln locator bore opening 72. Pre~erably, end portlon 48b is o~ a generally oval cros~-sectlonal conf~igu-10 ration and arranged such that it slidably engages only with~acing wall ~ur~aces Or locator bore opening 72, whioh are arranged immediately ad~acent opposite sides of a con~non plane pas3ing through openings 70 and 72. ~hi~ arrangement serves to accuratel~r center steel 44 in a direotion lengthwise o~ retainer 15 shoe 46, such that the end~ o~ steel 44 are equidistant ~rom retainer shoe ~ ace~ 46a and 46b, while at the same time not intsrfering with the ~eating Or steel bearing sur~aces 62 in sur~ace-to~sur~ace engagement with retainer bearing ~urrace 80.
Again rererring to Figs. 3 and 5, it will be seen 20 that bolts 50 are formed with threaded shank portion~ 50a, which are sized to be loosely acoommodated within steel mounting openings 70 and be threadably received within retainer shoe openings 86, and enlarged head portions 50b, which are adapted to be arranged to clampingly engage that one o~ steel olamping 25 sur~aces 60 spaced from engagement with retainer clamping sur-~ace 78. It will be understood that the sole purpose o~ bolts 50 is to clamp steel 44 Against retainer clamping ~urface 78 ater suoh steel has been accurately located vertically and horizontally relatlve to retalner shoe 46 by rebainor bearing 30 sur~ace 80 and locator pln 48, respectively.

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-~- ; : . . ., ' The posltional relationship o~ threadod opening~
84 relative to locator reoeiving op0nlng 86 and their pasitional relationship relative to retainer bearing sur~aGe 82 i3 pre-~erably ldentical to the positional relationshlp of mounting 5 bore openings 70 relative to locator bore openlng 72 and their positional relationship to bearing ~ aoes 56. This permits clamping sur~ace3 60 to be alternately olamped again t retainer bearlng surrace 78 wi~h bearing sur~aces 62 alternately disoussed in bear.ing engagement with retainer bearing sur~ace 80~ whereby 10 to seleotively po~ition outting edges 66a-66d one at a time in an operative cutting position relative to retainer shoe 46, which i9 shown ln Fig. 2 as being oocupied by cutting edge 66a, Thus., that one of the four cutting edges, whi¢h at any given time oonstitutes the operative outting edge Or steel 44, is de-15 fined by that one of olamping surfaces 60, which is arranged inengagement with retainer olamping surface 78~ and an outer one of bearing surraces 62, lr~hich is spaced from engagement with retainer bearing surface 80. In the preferred ~orm of the present invention, punch steel 44 and die steel 44 - are of iden-20 tical size and oonstruction in order to permit interchangeable mounting thereof on the punoh and die retainer shoes, It will be appreoiated that the above desoribed arrangement of parts permits resharpening of outting edges 66a-66d by ~he simple expedient of grinding clamping surfaoes 25 60; the resultant reduckion ln thickness o~ steel 44 being com-pen~ated for by forming threaded openings 84 o~ a depth suffi-oient to prevent bolt shank portions 50a from "bottoming out", untll the steel has been ground to some given minimum or design thiokness requiring its replaoement, Also, it will be appreoi-30 ated that this mode Or resharpening outtlng edges 66a-66d doe~

not change the placement o~ the operative outting edge o~ the steel relatlve to elther retainer clampin~ surrace 80 or re-ta~ner bearing sur~ace 82, and there~ore avoids time oonsuming ad~ustment o~ units 40 and 42 relatlve to one another in a hori~ontal direction and/or ad~ustmsnts o~ the dle set olosed position of punch unl~ ~6~ which would otherwise be required.
Further, the above des~ribed method of sharpening the cuttin~
edges o~ steels 44 and 44t possesses the additional ad~antage that the coplanar relationship o~ rib support sur~a¢e 56 and the upper steel bearing surface 62~ 18 not alter~d during the useful li~e of steel 44t.
Again re~erring to Fig~. 2 and 3, it will be under~tood that workpieoe presser-~oot assembly 52 inoludes a presser-~oot or plate havlng a generally reotangular and down-wardly faoing presser or pressure surraoe 92; a plurality o~guide.or support rods 94, which are slidably supported one within eaoh o~ mounting openings 88 and serve to mount presser ~oot 90 within an elongated reoess de~lned by retainer olearance sur~aoe 82 and pro~ecting port~on 60a o~ clamping surface 60 ~or verti-oally direoted re¢iprooating movements between it~ extended and retracted positions shown in Figs. 1 and 2, respeotively; and suitable bias mean~, suah a~ a plurality of ooil type compres~ion spring de~ice~ 96, whiah are operable to normally maintaln pre~ser ~oot 90 ln its extended po~ition~ Each Or support rods 94 Includes rod head and shank portions 98 and 100, whioh are guided ~or vertloally direoted reciprooating mo~ements within as~ociated mounting opening upper and central portions 88a and 88c, respeo~ively, such that each rod shank portion 100 extends downwardly through its as~ooiated mounting opening lower portion 88b and beyond clearance surface 82 ~or threaded attachment wlth .
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pres~er rOo~ 90. Spr~-ng devices 96 ~ro arrsnged ~no con¢en-trically o~ each Or shank portions lO0 ~or opposite end bearing engagement with downwardly ~acing ~nn~lar abutment sur~a¢es 88b and the upwardly ~acing surrace o~ presser foot gO~ and thereby normally ser~e to bias the prssser rOot into its above mentioned extended position~ whioh is determined by engagement of rod head portions 98 with upwardly racing annular abutment surraces 88d.
By again re~erring to the drawings, it will be understood that the positional relatlon~hip o~ lo¢ator openings 26a and 30a relative to one another and locator po~t9 74 and 74~, serves to horizontally posltionally locate punch and die units 40 and 42 of each die unit 12 such that the axes of thelr locator pin receiving openings 86 and 86~ are parallel and lie within a common vertlcally disposed plane; retainer clamping ~ur~aces 78 and 781 are parallel and arranged to ~ace in opposite directions; and presser surface 92 is disposed parallel to and arranged to bridge across rib support sur~ace 56 and the upper bearing surface 62~ o~ steel 44l . As a result~ steels 44 and 44~ are positionéd such that bearing ~urfaces 62 and 62~ are parallel; their respecti~e end sur~aces 64 and 64~ lie in a coplanar relationship; and clamping sur~aces 60 and 60t, which engage with retainer clamping surraces 78 and 78~, are parallel and ~ace in opposite directions, The spacing between pro~ecting portions 60a and 60al, as measured in a direction normal thereto, is such as to in~ure proper ¢utting off or shearing Or workpiece 14 a~ portions 60a and 60al are moved between their o~rset and lapping position9 shown in Figs. 1 and 2, re9pectively.
By viewing Figs. 3 and 4, it will be understood that the po~itlonal relationship o~ locator openings 26a and 30a relative to one another and locator posts 74 and 74-. . - . . .
: ' , -12~
~0499Z2 addltionally serve~ to horizont~lly position~lly looate punch ~nd die units 40 and 42 o~ ad~acently diqposed or tandemly arranged die units 12, such that the steel end sur~a¢e9 64 and 641 o~
ad~acent units are arranged in proxim~te surface engagement and 5 the operative cutting edge~ o~ ad~acent ones of steels 44 and 441 are dl~posed in an aligned~ end to end relationship in order to effeot ~cutting-off~ of workplece 14 along a line whoYe l~ngth corre3pond~ to the sum o~ the lengths of the operatlv~
cuttlng ed~es o~ ad~acent units. While lt i8 pre~erable ~rom 10 the ~tandpoint of manu~aoturing and inventory aonsiderations to provide only a single size modular cuto~f die unit~ such that the total length of cut is a multiple Or the length of the operative outting edge Or the die steels employed in each unit~
it would~ however~ be posslble to provide the units ln various 15 9izes as deslred.
A9 indicated above~ the positional location o~
the modular cutoff die unit 12 vrithin die set 10 and the number o~ such unit~ to b~ arranged in tandem will be determined by press set up requlrements~ Onoe these requlremants have been 20 determined, approprlately sized and arranged locator holes and clearance openings are ~ormed in templets 26 and 30 to insure that punch and die unlts 40 and 42 of each unit 12 are ~rranged in opsrative vertical registration when these punoh and die units are fixed to their assocl~ted templets and the latter 25 fixed to the punch and dle shoes in the manner shown ln Fig. 1.
Thereafter~ a workple¢e ~ to ~e severed is placed on die unit 42 ~or supporting engagement with rlb support sur~aoe 56 and the upwardly faoing bearing surfaoe of steel 44- . The workpiece may therea~ter be severed by oausing movement o~ punoh shoe 16 down-30 wardly towards dle shoe 18 lnto the die set olosed position shann ~0499Z;~

in Flg. 2, Durlng clo~lng movements o~ punch shoe 16, pres~erfoot 90 reside~ in lt~ extended position relative to punch re-talner shoe 46 until presser su~ace 92 i~ brought into engage-ment with the upper sur~aae Or workplece 14, whereby to arrest contlnued downWardly dlreoted movement Or presser ~oot 90 while ¢ausing relativ~ movement between presser ~oot 90 and punch ~e-tainer shoe 48 against the blas o~'springs 96~ as the punch ~e-talner shoe moves towards and into its die cl~qed position ~hown ln Fig. 2. The arrangement 19 su¢h as to allow for the positive clamping of workpiece ~ prior to initiation o~ the ~cutting-of~"
operation in order to prevent horlzontal displac~ments o~ the workpiece,'which would otherwise ocour incident to the passage of steel 44 through the workpiece.
While a ~resently proposed commerclal ~orm o~
the modular cuto~f die unit has been des¢ribed ln detall, it is anticipated that the se~eral novel features o~ such unit may be incorporated within outo~r dle units o~ otherwise diverse con-struction.' Thus, as by way of example,' the present die unit is not limited in use by the specific manner in which its associ-ated punch and die units are positionally ~ixed within a dieset nor by the construotion o~ such die set. Moreover~' it is antlcipated that the feature of forming one or both of the punch and die steels with four ~electively positioned cutting edges may be employed in cuto~ units~ which are not intended to be arranged ln tandem and there~ore may omit the lo¢ator pins or comparable steel centering devices. On the other handl it is '~ contemplated that punch and die steels characterized as havlng only a single cutting edge may be centered relative to their ; asso¢iated retainer shoes by means o~ locator plns or comparable devlces in order to permit two or more cutor~ dle units to be arranged in tandem, - - . . .
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~0499ZZ

This application is a divisional application from application serial No. 252,726 filed on May 17, 1976.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A steel adapted for use interchangeably as a punch and die steel of a cutoff unit, said steel being of a rectangular parallelepiped configuration defined by parallel first and parallel second side surfaces and parallel end surfaces, said first and second side surfaces cooperating at their junctures to define four cutting edges extending between said end surfaces, said first surfaces having a widthwise dimension in excess of the widthwise dimension of said second surfaces, said steel being formed with a single steel locator bore opening and at least two steel mounting bore openings, said locator and mounting bore openings extending between said first surfaces and having their axes arranged in parallel and located within a common plane arranged equidistant from said second surfaces, said locator bore opening being arranged equidistant from said end surfaces, and said mounting openings being arranged one-half between said locator bore opening and one of said end surfaces and another half between said locator bore opening and another of said end surfaces, and the positional relationship of said one half and said other half of said mounting openings relative to said locator bore opening being identical.