US2522452A - Pressure or load control device for metalworking presses - Google Patents

Description

Sept. 12, 1950 E. K.'JOHANSEN 2,522,452

. PRESSURE OR LOAD CONTROL DEVICE EOR METALWORKING PRESSES Filed June 12, 1950 3 Sheets-Sheet 1 INVENTOR;

v EINAR K. JOHANSEN WW, M 9 ATT'YS Sept. 12, 1950 E. K. JOHANSEN PRESSURE 0R LOAD CONTROL DEVICE FOR METALWORKING PRESSES 3 Sheets-She et 2 Filed June 12, 1950 34 INVENTOR:

EINAR K; JOHANSEN Sept. 12, 1950 E. K. JOHANSEN 2,522,452 I PRESSURE 0R LOAD CONTROL DEVICE FOR METALWORKING PRESSES Filed June 12, 1960 3 Sheets-Sheet 3 m i m I N L |||||||||||J||| 1 m M a s M w m m m I 9 I 6 H M 4 a 6 3 6 f\ 1- n a 7 6 V F v I W n 3 a a w u 7 5 I EIINAR K. JOHANSEN ATT'YS Patented Sept. 12, 1950 rm OFFICE."

PRESSURE ORL OAD CONTROL DEVICE FOR, METALWORKING PRESSES Einar K. Johansen,- "Oak rarkjni, assignor to Clearing Machine Corporation, Chicago, Ill, a corporation of Illinois Application June 12, 1950, Serial No. 167,501

' This invention relates in general to metal working and forming presses of the mechanical type and is'particularly directed to a novel form of pressure or load control device which prevents an Overload from occurring on certain parts of the press and which may also be used for adju'sting and regulating the pressure exerted between certain parts of the press. The pressure or load control device embodying the present invention is applicable to metal working presses which are mechanically operated and maybe applied to different parts of the pressto accomplish various specific results, all of which will be clearly set forth hereinafter.

Many metal working presses are so constructed as to consist of a pair of uprights havin a crown atone end thereof and a bed at the other end thereof held together by a plurality of tie rods. .One form of a pressure or load control 'de'vice'embodying the present invention has heretofore been applied to the tie rods in such a press, and this feature has been disclosed and claimed in my earlier filed copending application bearing Serial No..15 4,699, filed April '7, 1950.

Metalworking and forming presses, however, diifer as to their specific details of construction. Some such presses may have a solid frame without any tie rods to hold the crown and bed together. There are also single action presses wherein an upper slide having a die affixed thereto is caused to come against a metal work piece between the upper die and the lower die located on the bed of the press. Another form of metal working press is known as the double action type wherein a blank holder is first caused to move in a direction to hold the metal blank in place while a second slide, having a die affixed there to, moves to perform a forming operation. Larger presses may have what is known as a triple action which may be similar to the double action. with the addition of a third action slide moving against the blank to cause a further forming operation on the metal blank or work piece. Some of these presses may be operated by driving mechanism located at the top of the press, and others may have the driving mechanism in the lower portion of the press. Whenthe driving mechanism is located in the bottom of the 'press the frame is not necessarily held together by tie rods, nor is it necessar y a s id irame type.

6 Claims. (Cl. 11338) One difiic'ulty which has always been present in metal working presses of the mechanical type is the possibility ofv stalling or breaking certain parts of the press due to an overload. The overload may be caused by the die setter during the preliminary steps of die setting, if he should set the die in the movable'slide too near the opposite die. On the other hand, an operator of the press may occasionally move two blanks instead of one into position on the die which would also cause an overload in the press and either cause some part of the press to break, or may cause the. clutch to slip resulting in the press stalling at the end of its normal stroke. It is evident that when press breakage occurs, not only costly repairs are incurred, but also a lengthy delay in. production may result during the necessary time for repair.

The pressure or load control device of the present invention is adaptable to presses of the tie rod construction, the solid frame construction, and the type of press wherein the drive is located in the lower portion of the press. The present form of the invention illustrates the applicability thereof to either the blank holder slide or to the slide or slides carrying the forming dies,

whether the press be of a solid frame or tie rod construction, or whether it be a single action, double action, or triple action press, and regardless of where the driving mechanism is located.

In most instances the various slides of a metal WOIklng press have adjusting means associated therewith in order to adjust the blank holder slide or the draw slides either toward or away from the opposite die to compensate for different pressures, as well as different thicknesses :inthe press, an overload will occur. The device ofthe present invention compensates for this 'variaton in thickness of the blank, thus eliminating the necessity for a fine selection in stock thickness or adjusting the press for each variation. This, in turn, results in great economy because of the reduction in the number of worked pieces or products which must be discarded.

With the foregoing considerations in mind, it is a principal object of the present invention to provide a pressure or load control device which is directly associated with one or more slides in a metal working press.

Another object of the invention is to provide a pressure or load control device which is associated with one or more slides in a metal working press and which compensates for the inaccuracies of a die setter during the preliminary steps of die setting, as wellas-forzthevariations in blank thicknesses to prevent an overload in the press from stallin the press or causingv breakage to occur therein.

A further object of the invention is to provide a novel form of pressure or load control device in association with the "blank holderslide of a metal working press, whereby thepressure exerted by the blank holder slide on the metal blank may be finely adjusted withoutthe necessity'for the painstaking adjustment of ."the adjusting screws.

.A still further object of .theiinven'ti-on is to provide apressureor loadcontroldevice associated with one of the forming slides in a metal work- -ing press to protect thepress against overload.

Still another object of the invention is .to provide a novel pressure or loadcontrol 'device associated with'one'ormore slides ofua metal working press wherein a yieldableforce will be caused to yield when the pressure created .by the slide against the work reaches a predetermined amount, whereby the pressure against the blank maybe regulated 'if'the device .is associated with 'the blank holderslideorthe press will be protected against overlcadif the device is, associated with either'the blank holder slide or the forming slide or slides of the press.

.A further object of the invention is to pro- "vide a pressure or. load controldevice for :a metal working press,'wherein a lever armis connected at 'one end thereof between a slideof the press and the mechanism which reciprocatesthe slide, and the other end thereof is connected to a yield- '-able means .mounted eitherdirectl on the slide or'o-n .a support member which reciprocateswith the. slide. An eccentric arrangement adjacent one end of the leverarrn will cause .theyieldable means to operate when a. predetermined pressure or load is reached on the .slide with which the device. is associated.

Still anotherand more specificobject of the invention is toprovide a pressure or'load control device for a metal working press whereina yieldable force suchas air or other fluid is exerted .against one end of an eccentrically mounted lever arm, thereby to rotate the lever arm in. one direction when thev fluid cylinder to which itis attached is charged thereby setting ,up an initial stress. The other end of the leverermis then connected between one of the slides and the mechanism which reciprocates thatslide, soth'at when a predetermined pressure orloadis reached, such load will-rotate-the lever arm in the opposite direction to that in .whichit was rotated during the charging of. the. c linder, thereby .to .prevent the occurrence of any excessive pressure or overload.

-Other objects and advantages-of the invention .Will become-.lapparent upon readingthe following description taken in conjunction with the accompanying drawings in which:

Fig. 1 is an elevational view of the pressure or load control device of the present invention illustrated as applied to one of the forming slides of a metal working press;

Fig. 2 is a vertical sectional View of the device taken along the plane of line 2-2 of Fig. 1;

Fig. 3 is a horizontal sectional view taken along the plane of line 3-3 of Fig. 2;

.Fig.--4 isa view partlyin-elevation and partly in vertical'section of twoof the devices-embodying the invention as applied to the blank holder slide of a press wherein the adjusting screws for the blank holder are manually operated;

Fig.5 is ahorizontal sectional view taken along theplane of line 55 of Fig. 6 and illustrating "the use of the present invention as applied to aa blank holder slide which is adapted to be mechanical-l adjusted; and

Fig. 6 is .a view partly in elevation and partly in section of a press with the invention applied thereto as illustrated in Fig. 5.

In the case of double and triple action presses, the first action slide is sometimessreierred' to as a-blank holder slide which, 7 during the :-;initial :cycle of the -press,.is the first to move? against the work or blank to holde'it' in position while the metalblank is being-operated upon by ithe =forming slide-or slides.

.In a double action press thersecond: action :slide is the forming slide which has .a die aflixed thereto. This ---forming slide is sometimes mounted within the blank holder slide-and is caused to.reciprocate. vertically. It may. also-be mounted so as. to reciprocate ina directiomopposite tothatofthe blank..holder. ,.It is.called a second action slide ,because of v the a fact that it: is operated .to. cause a. forming operationszon .the blankafter .theblank holder has come,..against the ,blank .andduring .the .dwell of v.the blank holderv while it is holdingthe b-lank-.in..positicn. Thissecond slide..or..forming. slide performs its forming operation and then .returnsto -its'initial position after. which -the blankiholdemreturns to its .initial positionrand the .productiis removed from the. press.

Figs. 1,. Zand' 3 oithe 1 drawings, to which. more particular reference willnow' be,made,.il1ustr-ates the pressure or load. control device of the present invention as applied tothe forming slide of either 'a single, double or triple .aotion press. (Inasmuch. as presses ofthisgeneral constructionaare well-known, the details thereof .have .not been shown, it being sufficient to indicate theslide itself by the numeral. i whichiscaused .to reciprocate in guideways 2.

The slide is caused to reciprocateby an suitable driving arrangement. In some instances, the slide is reciprocated bysa simple crank-device. The slides in later improved forms-of metal working presses are caused .to reciprocate by various linkage and eccentric.arrangements iorimproved operation. The specific driving means, however, is of little importancefrom the standpoint of the present invention and for. purposes of illustration, the drive means. forthe forming slide .has been shown as an ordinary crank device. A drive shaft 3 has an eccentric or crank portion 5 associated therewith to which .a link-6 is secured. Ordinarily, the lower end-of link- :6 .Will be connected directly by meansof apivotpinto .the forming slide thereb to reciprocate the..slide. as the shaft with the crank 5 .thereonrotates.

In the case of a single action press, there may be only one such crank and "the slide. In larger presses of the single, double link arrangement for and triple action types, it is customary to'have a plurality of such eccentrics or cranks so that a connection will be made between the crank and drawings, only one of the pressure or load control devices has been shown, but it will be understood that more than one such device may be applied to thesame 'slide, if desired.

The pressure or load device of the present invention consists of a cylinder 1 having a piston 8 adapted to reciprocate therein. The bottom 9 of cylinder 1 has an ear or other suitable connecting member In arranged so that it may be pivotally connected to a part I I of the slide by means of a pivot pin l2.

piston rod I3 is connected to the piston 8 and extends through the top I 4 of the cylinder a suitable distance so that its upper end may be connected by means of a pivot pin i5to one end of a lever arm generally indicated at l6. The lever arm l6 forms a clevis at its opposite end which is provided with circular side members l'l and l8 and an intermediate portion l9 partially sur-, rounding an arcuate recess 20. Each portion I! and His circular and has a center of curvature as indicated by the arrow 2| in Fig. 2. Each portion I! and [8 also has an opening therethrough adapted to receive a pin 22 so that the axis of the pin will be eccentricto the center of curvature of the portions l1 and IS. The axis of the pin 22 is indicated by the arrow 23 in Fig. 2 and it will be evident that the distance between the points 2| and 23 is the eccentricity between the axis of the pin 22 and the axis about which lever arm I6 may rotate. The lower end of link 6 extends downwardly into the opening 20 between the sides I! and I8 of the lever arm 5 and surrounds the pin 22.

The. pin 22 also extends between the spaced sides 24 of a bearing member. The bearing member is suitably attached or fixed to the upper part of an adjusting member 28. This adjusting member may assume any suitable form and in this particular instance as illustrated in Fig. 2 of the. drawings, it consists'oi a downwardly extending screw threaded member 29. In the particular embodiment shown, there may be one such screw adjustment at each of various locations on the slide.

An internally threaded bevel gear 30 engages the threaded member 29 and this bevel gearhas a flange 3| at one end adapted to rotate in an annular recess provided in asleeve 32. It will be evident that as the crank 5 rotates to reciprocate the link 6, the link will carry with it the pin 22, the bearing for the eccentric, the screw 29 and the slide I mounted thereon. Since the air cylinder 1 is also mounted on the slide, it will reciprocate therewith. 1

When an adjustment of the slide is desired either for die setting purposes or for adjusting the slide for different thicknesses of metal to be worked upon. the bevel gear 3E may be rotated to thereby cause the slide to be raised or lowered.- It will be evident that the stroke of the slide will not be varied because the crank distance is fixed, but the adjustment will determine the lowermost position of the slide with respect to a lower die. Fluid under pressure is placed in the cylinder 1 abovethe piston a to lower the piston to-a point where stop member 3 on lever arm It comes against flange 28, as shownin Fig. 2. The fluid pressure against the piston maybe varied and will depend upon the size of the press and the amount or pressure of load to be exerted thereby. In the embodiment shown in Fig. 2, it will be noted that the center of the eccentric about which the lever arm l6 rotates and indicated by the numeral 2 I is in direct alignment with the center of the crank 5 and the center of the screw 29'. The center or axis of the pin22 in'Fig. 2 is located a short distance to the rightofthe eccentric center 2|, this center being indicated by the numeral 23. It will be evident that during the operation of the press, or during the preliminary die setting operation, if the slide is being adjusted or has been adjusted so that in the lowermost position of the slide a predetermined load will occur, the "press may'function continuously without'trouble. If, however, in the die setting operation the slide is set toolow, or if during operation of the press,- two work pieces are moved'into the die instead of one, or if the work piece is too thick or is uneven so that it is thicker on one sidelthan on the other, this-load or'p'ressure exerted by the slide when it reaches the-lowermost position will tend to exceed that pressure for which it was originally set. When this condition exists ina press without the present invention applied "thereto, either the press will stall dueto the fact that the crank cannot continue its movement to the lowermost position thereof, or the press or die may fail or fracture. i

With the presentinvention applied to the press as illustrated in'Figs. l, 2 and 3, when the load exerted by the slide multiplied by the eccentric distance between points 2| and 23 exceeds the total fluid pressure acting onxthe piston 8'multi-. plied by the length of lever arm l6 due to continued movement of link 6 by operation of crank 5, the force will be transmittedthrough the cocentric and downwardly on point 23 causing a rotation of lever arm !5 in a clockwise direction, as viewed in Fig. 2. This movement of lever arm 16 will elevatethe piston rod l3 and piston 8 against the fluid pressure'in cylinder 1, thereby yielding and allowing the crank and link to complete its downward movement without overload or exces sive pressure, thereby preventing damage to'the through the axis about which the lever arm; 16

rotates, and with the center of the pin 22 on the right-hand side thereof, as viewed in Fig. 2. It will be evident that other specific arrangements of the eccentric may also be had Without departing from the spirit of the invention. For example, the center line of the crank and screw may, if desired, pass directly through the center of .pin 22. In this case, however, 1 the axis 2!. about which the lever arm I 6 rotates will still be on the left side of the center of the pin as viewed in Fig. 2, so that the downward force exerted will be on the right-handsideof axis 2|. and still cause clockwise rotation ofleve arm It to move, piston 8 upwardly against the fluid pressure in the cylinder I.

Another possible arrangement of the eccentric would be to place the axis about which the lever arm It rocks on the right-hand side of the center of pin 22. In this arrangement the center line of, the crank and screw would pass through the center of the pin and the overload or excessive pressureawould 1' thencause the 1 lever-arm. .l 6 to rotate in a counterclockwise direction. When the lever arm rotates in a counterclockwise direction, the piston -.8 will-move downwardly instead of upwardly; sothat-it will begnecessary to have the fluid: pressure -in the cylinder below 1 the .piston 8 instead of above as illustrated in-Fig. 2.

Any :of these various-arrangements will be obvious to those skilled in the art and ,Wl11' not change the fundamentalv operation 1 of the invention as disclosed herein.

It-may be desirable in instances where more than ,one adjustment screw is used to have a greater pressure on one side or one corner of the slidethan on the other side or corner. varying pressure can be obtained bythe adjustmentloftheiiuid pressure in each cylinder. One

cylinder may have the-pressure therein increased so that a'greaterpressure on that corner or side of gthe" slide awill begobtained. Thus with the aid ofathis invention, the pressure which would be exerted on any :given point of the slide can be varied by varying the fluid pressure within-the respective'cylinder or cylinders. In actual practice'sthe rough-adjustment-may be made by the adjusting screw and the' finer adjustmentmay be made'by'regulating the fluid pressure within the cylinder.

Referring now more particularly to Fig. 4 of the drawings; thisillustrates the pressure or load controldevice asappliecl-to the blank holder of a double or triple action metal working press, wherein the adjustment of the blank holder may be made manually. The blank holder in a press ofthis character'constitutes the outer slide which reciprocates toward-and-away from the work to hold-"the blank in position while the forming Slide-is performing the forming operation thereon. x'Ihespacing members'33 are provided with suitable guideways within which the blank holder 34 isa'dapted to reciprocate. The blank holder is :usually operated by a plurality of cranks or eccentric driving-mechanisms having associated therewithlinks' 35.

"In the form of press illustrated in 'Fig. 4 there are'four such links35, one at each corner of the blank holder and two of which may be seen in Fig.4 of the drawings. The'lower end of each link-35is sutiably mountedin a bearing support 36 formed integrally with or otherwise suitably secured to an elongated downwardly extending screw member 3'1. The screw member 37 constitutes the adjusting screw and passes downwardly through a boss 38 on the blank holder. Eachsuch'assembly includesan upper collar 39 and a lower collar 49 having internal threads engaging the threads on the adjusting screw-31.

The adjustment of the blank holder in the press illustrated in Fig. 4 is accomplished manually by means of the collars 39 andAO on each of the adjusting screws 31. When the blank holder is to be raised the upper collar .39 is loosened and the lower collar 40 is turned against theflunderside of boss 33. The upperrcollar 39 is then tightened and that corner of .the .blank holder remains inv adjusted position. The same procedure may .thenbefollowed with each of the other adjusting screws 31.

When the blank holder is to be lowered the lowercpllarrilfl isunscrewedandthe upper collar 39 is turned to move downwardly against the upper side .ofthe boss 38-to maintain the blank holder inadjustedpositmn. It. would not depart rom.etloehspirit. of the invention to reverse the adjusting mechanism by providing an internally This threaded v-adiusting 1: scr w and :make :r diustin nutszthreadedly engaging the screw; at. --,opposite ends thereof.

It is desirable to have-apressure. or loadcontrol device embodying the present ,inventionrassociated with each adjusting-screw 31=on;the;b1ank holder although it is :not necessary that thisrarrangementbe followed. Thepreferred structure of the invention as applied to thezt-yp-exof press illustrated inFig. .4 is to. provide amounting bar 4| securedat each endthereof to the lower end of adjusting screws.31 atone sideof' the press. A pair 10f cylinders 42 may then vbe mounted side by side on this .bar' 4| through mounting means such as the ears 43' and pins.

Each cylinder iz has a.pistoni45:adaptedwto reciprocate therein and has connected theretowa piston. rod .46 extending upwardly through" the top of cylinder. "The upper end of each piston rod 45 is pivotally connected by -'means ofialpivot pin 47 to one end of a lever arm 48. 'Thislever arm 48 issimilarin allrespectsto the lever arm [6 as described previously inconnection' with Figs. 1, 2 and 3. "The lever arm 48is*=provided with anintermediate arcuate portion dll partially surrounding a recess and hasside openings to receive a-pin 50. Theopenings through the sides are arranged eccentrically to the center or axis of pin 58 so that the axis of rotation of lever arm 38 will be substantially at'the pointshown by the numeral 5! in Fig. 4. "The-axis of-pin 50 is indicated by the arrow- 52 so that theeccentricity'will be the distance between the axis '52 and the axis 5|.

*Asbefore, fluid-under pressure will be'applied to cylinder-42 above the piston 45 so that-a predetermined force against the lever arm 48"will be necessary to move the piston 45 upwardly against the fluid pressure therein. The operation of the invention as applied to a blank holder is'similar in all respects to the operation thereof as previously explained when the pressure or load control device is applied-to a-forming slide. The invention becomes important with respect to the blank holder from the standpoint of pressure to be exerted against the blank while it isbeing held during the formingoperation. "The blank holder must be adjusted for different thicknesses of metal the same as the forming slide and if the metal is of uneven thickness, a greater pressure may be exerted on one side of the press than on the other. Likewise, it two blanks instead of one are inadvertently placed in the press, anexcessive pressure will result and cause possible ,damage to the press or die.

Here again,;for,any given setting of the blank holder the pressure exerted will be theload times the eccentric distance between the axes 5| and 52. The fluid pressure in the cylinder "may also be varied 'for any iven pressure on the blank holder, so that when the pressure on the blank holder multiplied by the eccentric distance exceeds the total fluid pressure against thepiston 45 multiplied by the lever distancebetween pivot pin. and the eccentric axis 5!, such pressure will be exerted on the axis 52 .of .pin, fiflto move itdownwardly resultinginanupward or clockwiserotation ofqlever armfifi asiviewedgatthe right-hand side of Fig. 4. This movement, of coursecausespistonfifi to move upwardly against the .fluid pressure in the cylinder. This yielding action prevents ,excessive...pressure of the --blank holder. from causing .any-rdamage to the press or die.

Again the. fluid pressure .in each .cyI-indenmay be varied so that it will require more pressure to become excessive at one corner or one side of the press than the other. Also, the adjustment of the blank holder need not be as fine as in presses heretofore known because of the fact that excessive pressure or overload is not hazardous due to the transfer of this excessive pressure to accomplished manually. In Figs. and 6 the spacer members are indicated by the numeral 53, and the type of press shown also includes the tie rods 54 which hold the crown and bed of the press against the ends of the spacer members 53.

The blank holder is shown at 55 and is adapted to be 'reciprocated in guides 56 provided on the inner sides of the spacer members 53.

Links 51 are secured at their upper ends in any well-known manner to cranks, toggle links or an eccentric drive mechanism, whereby the blank holder 55 may be reciprocated. The lower ends of links 51 are mounted in bearing members 58 each of which has an integral portion 59 extending downwardly through the upper part of the blank holder and terminating in an elongated adjusting screw 60.

Similar to Fig. 4, a transverse mountin bar 6| extends between the lower ends of screws 30 on each side of the machine to accommodate the mounting of cylinders 52 thereon. Each cylinder 62 has a piston 63 adapted to reciprocate therein, and a piston rod 64 extending upwardly frompiston 63 through the top of the cylinder 52 and secured at its upper end by means of a pivot pin 65 to one end of a lever arm 66. The lever arm construction 66 is like that of. lever arm 48 in Fig. 4 and lever arm I6 in Figs. 1, 2 and 3. This lever arm consists of an arcuate portion 51 partially surrounding a recess between the sides thereof, the sides being provided with an opening for the reception of pivot pin 68. The arrangement is such that the center of the eccentric or the axis about which lever arm 66. rotates is indicated by the arrow 59. The center or axis of pin 68 is indicated at 10. As before, when the blank holder reaches its lowermost position and exerts pressure on the blank to be drawn, the pressure will build up to a predetermined amount. If the device of the present invention is not applied thereto, the pressure may become excessive and thus may cause damage or stalling of the press. With the device of the invention herein applied as illustrated in Figs. 5 and 6. when the pressure of the blank holder reaches a predetermined amount, any pressure which tends to be exerted in excess of that amount will cause the center or axis of pin to move downwardly about the axis 69 as a center, thereby impartin a clockwise movement to lever arm 66 as viewed pinion 12' in mesh with a gear. '13 on shaftld.

A pinion is" mounted adjacent each end of 10 shaft 14 on opposite sides of the center of the press in engagement with a gear 15 on shaft 11. Suitable means on shaft ll, such as a Worm screw 'lla, engages a worm gear on nut 18 threadedly engaged with each of the adjusting screws 60., Rotation of these gears or nuts 18 will cause the blank holder to be either raised or lowered.

The ends of shaft ll have bevel gears 19 engaging bevel gears 80 on a shaft Bl at opposite sides of the press. The other ends of each shaft 8| has a bevel gear 82 thereon in mesh with a, bevel gear 83 on similar shafts 84. Each shaft 84 has suitable gears thereon adapted to rotate internally threaded gear members threadedly engaged with the adjusting screws at the opposite side of the press, so that operation of motor II will cause the blank holder 55 to be raised or lowered at all points thereof simultaneously.

Also, in this form of the invention, although the adjustment of the blank holder may be different from that shown in Fig. 4, the pressure to be exerted on any side or corner of the blank holder can be regulated by the fluid pressure Within the particular cylinder associated with any particular adjusting screw.

In my above referred to copending application, the device of the present invention has been described as being associated with one or more of the tie rods in a metal working press. The invention has been disclosed herein as being associated with either the forming slide or the blank holder of a metal working press. It may be desirable to apply the invention to the lower or third action forming slide in a triple action press and this may be done in a manner identical with that herein disclosed with respect to the second forming slide.

The blank holder is often referred to as an outer slide, and it is therefore clear that when the inventionherein isreferred to as being applied to one or more slides of a metal working press, it is intended to mean that the pressure or load control device may be applied to the slide of a single action press; to either or both slides of a double action press, and to any one or to all three of the slides in a triple action press. It is likewise true that where the press is of a tie rod construction, the device of the present invention may be applied thereto as disclosed in my copending application either alone or in conjunction with one or more of the slides as disclosed herein.

The device has been referred to as either a pressure control device or a load control device. The

, reason for this is that technically when the device is applied to the outer slide or blank holder, its functions are both pressure regulation, and load control because the pressure of the blank holder against the work is being regulated, and, at the same time, overload is being prevented. When the device is applied to a forming slide of a press, then the primary consideration is the protection against overload. The device, however, functions in the same manner structurally whether its end function is to prevent excessive pressure or to prevent overload. Therefore, throughout this description, as well as in the claims appended hereto, the term load control is intended to mean either a means to control the overload on a forming slide or means to control the pressure on a blank holder slide.

In all forms of the invention disclosed herein, it is pointed out that one end of the lever arm is mounted in a bearing in the slide structure. This bearing may be either in the slide itself or in the adjusting means for the slide. The term,

ill. slide structure as used in the claims without further limitation is therefore intended to mean either the slide or the adjusting means therefor.

Changes may. be made in the form, construction and arrangement of parts from those disclosed herein without in any way departing from the spirit of the invention or sacrificing any of the attendant advantages thereof, provided, however, that such changes iall within the scope of the'claims appended hereto.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a metal working. press of the mechanical type having a reciprocating slide structure and mechanism for reciprocating the slide structure, a-pressure or load control device associated with the slide structure comprising a yieldable member mounted on the slide structure and movable therewith, a. lever arm connected. at one end thereof to said yieldable member and having its other end mounted in a bearing in the slide structure to rotate about an axis, a pivot pin passing through saidother endof the lever arm and a part of the mechanism for'reciprocating the slide-structure and having its axis parallel withsaid first axis and ofiset from said first axis andfrom the path of movement thereof, the lo cation of said pivot pin being such that the axial projection thereof. is containedwithin the axial projection of said hearing, whereby relative movement between the slide structure and the mechanism for reciprocatin'gthe slide structure tending toproduce excessive pressure or overload will causerotati'on of said lever arm about said first axis against the pressure of saidyieldable member.

2. Ina metal working press of the mechanical type having a reciprocating slide structure including adjusting: means mounted onthe slide, and mechanism for reciprocating the slide structure, a pressure or loadcontrol device associated with theslide structure, comprising a yieldable member mounted on the slide structure and movable therewith, a lever arm connected at one end thereof to said yieldable member and having its other endmounted in a bearing in the adjusting means to-rotate about an axis, a pivot pin passing through said other end of the lever arm and'a part of the mechanism for reciprocating the-slide structure and having its axis par allel with said first axis and offset from saidfirst axis and from the path of movement thereof, the location of said pivot pin being such that the axial projection thereof is contained within the axial projection ofsaidbearing, whereby relative movement between the adjusting means and the mechanism for reciprocating the slide structure tending toproduce excessive pressure or overload will cause rotation of said lever arm about able therewith, a lever arm connected at one end thereof to said fluid pressure means and having its other end mounted-in a bearing in the slide structure to rotate ahout an axis, a pivot pin passing through'said other end of the lever arm and a part of the mechanism for reciprocating the slide structure and having its axis parallel 12 with said first axis and oflset fromrsaid first axis and from the path of movementthereof, the :lo-"

cation of said pivot pin being such-that the. axial projection thereofis contained" Within the axial projection of said bearing, whereby. relative movement between the slide structure 'andthe mechanism for reciprocatingwthe slide structure tending to produce excessive pressure. or overload will cause rotation of said'lever: arm. about said first axis against'the pressureof saidfiuid pressure means.-

4. In a metalworking. press of the mechanical type having a reciprocating.slide-structure including adjusting means mounted on the. slide, and mechanism forreciprocatingthe slide structure, a pressure or "load control device associated with the slide structure, comprisingy'a flUidFDI'BS sure'means mounted on the slide structure-and movable therewith, a lever arm connected at one end thereof to-said fluid pressure'means' and having its other end mounted in abearinginthe adjusting means to rotate about. an axis, a'pivot pin passing through said other endof the lever arm and a part of the mechanism for reciprocating the slide structure and havingits axis parallel with said first axis and oifsetfrom said first axis and from the path of movement thereof, the location of said pivotpin being suchthat the axial projection thereof iscontained within the axial projection of said bearing, whereby relative movement between the adjusting means and the mechanism for reciprocatingth-e slide structure tending to produce excessive pressure or overload will cause rotation of said lever armabout said first axis against the pressure of said fiuid rpressure means.

5. In ametal Working press of the mechanical type having a reciprocating. slide structure and mechanism for reciprocating. the slide structure, apressure or loadcontrol device associated with the slide structure,.comprising anyieldable member mounted on the-slide structure and'movable therewith, a lever arm; connected at one end thereof tosaid yieldable member and. having its other endmounted in a bearing in the slide struc-. ture to rotate about an axis, a pivot pin passing through said other end'of the lever arm and. a part of the mechanism for reciprocating the slide structure and havingits axis parallelwith said first axis and so arranged. that .a plane passing through both of said axes will be substantially perpendicular to the dir'ection of 'forcethrough said pivot pinand the axial projection of said pivot pin will'be contained within the axial pro,- jcction of. said'bearing, whereby relative movement' between the slidev structure andthe mechanism for reciprocating the slidestructure tending to produce excessive pressure oroverload will cause rotation of said lever arm. about said. first axis against the pressure of said yielda'ble member.

6. In a metal working press of, themechanical type having a reciprocating slide structure and mechanism for reciprocatingthe slide structure, a pressure or load control device associated with the slide structure, comprising a fluid pressure means mounted on the slide structure and movable therewith, a lever arm connected at one end thereof to said fluid pressure means and having its other end mounted in a bearing in, the slide structure to rotate about an axis, a pivot'pin p ssing through said other end of the lever arm and'a part of the mechanism for reciprocating the slide structure and having its axis parallel with said first axis and so arranged that a planepassing through both of said axes will be substantially perpendicular to the direction of force through said pivot pin and the axial projection of said pivot pin will be contained within the axial projection of said bearing, whereby rela- 5 tive movement between the slide structure and the mechanism for reciprocating the slide structure tending to produce excessive pressure or overload will cause rotation of said lever arm about said first axis against the pressure of said 10 fluid pressure means.

EINAR K. J OHANSEN.

REFERENCES CITED The following references are of record in the 15 file of this patent:

Number Number 14 UNITED STATES PATENTS Name Date Wilzin Nov. 10, 1908 Roberts 1 Nov. 8, 1910 Smith May 30, 1922 Glasner et a1 July 7, 1925 Marghitan Sept. 30, 1930 Hawkins Feb. 9, 1932 Sloan et a1. Jan. 30, 1934 FOREIGN PATENTS Country Date Great Britain 1906

Images