US2865208A - Press - Google Patents

Description

Filed June 29, 1956 A. J. WACHT PRESS 6 Sheets-Sheet 1 AMM@ J INETOR.

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ATTORNEK United States Patent NilOli-ice PRESSA Andrew J. Wacht, Detroit, Mich. Agpugriqninpe-c9, 1956,f serial `-lvufssmqsn` 12 Claims. (Cl:y 74--725) This invention relates A to` presses sucht-asusedl in .stamping, pressure molding, plastic laminate molding, andsimilar operations. The presentapplication.isi-a continuation` in=partj of. my co-pending4 applicationSerial No..` 576,'845, led1on-April9, 1956, forTogglePress.

In spite of the fact' thatA the art ofr stampingand constructing presses is an old and welll advanced'.Y art, diliicultieshave been` encountered. in'utilizing suchy pressesA in manyloperations which have to bep-erforrnedin the present day-manufacturing processes. Insome of such operations, such, for-instance, asin-laminate plasticmolding, particularly when the workpiece has deep draws, considerable A diihculties have been` encountered .in the use of conventional presses. lnfperforming an operation ofsuch a nature, it is necessary to have considerable working space above the mold" or die in order to load apreform or workpiece into the-moldwithout'interferencefrom the movable portionofethe mold and to-.withdrawfthemolded workpiece from the stationary portion of the mold This condition requires a press having a very. long4 stroke in order to take care of movinglthe movableportionofthe moldzthrough aV considerable distance away from the stationary portion ofthe mold and .to move such movable portion to the work as well as through the workingf portion ofl its downward stroke. In addition, exceedingly high pressures maybe requirediat the endofssuchworking *portion.'of the downward stroke, ywhileverylight forces. are suiiicientl to bringl thev movable portionv tov the workf and towithdrawv it therefrom. f

Presses whichdevelop very high forces, suchas; toggle presses,.have arelatively shortstroke and, therefore, are nots always fullysuitabl'e for? such operations; On the other hand, presses `of other types that: haveY long. strokes are'. not capable of developing suiiiciently. high forces in certain portions of the working stroke. Useoffhydraulic presses with plurality. offcylindersto satisfy thesetreq'uirements 'has been resorted to in many instances under. the

theory that production of desired long strokeswith light forces and shortV strokes with high forces cannot be developedin a mechanical press. However, in addition. to various knowndisadvantages of` hydraulic devicesof: this nature, maintaining pressure thereon duringv` the curingoperation requires the use of hydraulic devices, running ofhydrauli'c pumps for considerable lengthoftima'which isnotf only expensive but results i`n`` undesirable heating 'of the hydraulic huid.

'The'. above diiculties are increased still further. when the object` to be moldedv isof considerable size such, for instance, as a laminate plastic or reinforced.` plastic boat, andthe pressures to be exerted on. the preform onwerkpiecehas to be; distributed over a very, large, areai'resulting invery high, total forcewhichhas to be applied centrally of the movable portionofthemoldand; distributed through a large area from the center ofvmoyableportion of the mold. This condition may result. in objectionably large deection of such larger movable portionatits periphery requiring heavy ribbing:andl Qthsrtrinfor- Patented Dec. 23, 1958 2i ments in-its construction, andresulting in-exceedingly cumbersome and heavy structure.

A- similar, diiculty is also experienced in fabricating various sheet material panels with the aid of so-called' rule dies, i. e. dies. made, ofasteel bladelbent. to a certainoutlinefor cutting out variousvr forms fromv materials lsuch as ber, paper andthe like. It should be-understood that for cutting a panel out off such! strongmaterialasfber for use, 'for instance, in an automobile door,`pressur`e as high as,200tons may-berequired. This. results. from the-fact that suchdies donot cutonabiaslike shears or scissors, or solid dies., but?mustlcutthelentirethicknessof the materialfthrough vthe entire periphery of theworkpiece vat.y thev same. time. v i t While-conventional presses, suchas toggle. presses, may be constructed that would fully satisfy the requirements for` stamping or4 molding a certain' workpiece or preform, it is obvious that this cannot be done. for avarietyof stamping and molding operations that may have to be performed o natpress during its'lifetime. Therefore, as `soon asA the press .especially designed for acertainJdeIinite workpiece has. to be used forfanother workpiece, it may become wholly unsuitable. Obviously, building a, press for. each piece ofwork ispossible only. invery rareinstances.

One of the objects ofthe presentinvention is to provide an improvedpress for stamping, laminate molding, rubber moldingandf. similar operations, in whichthe above difficultiesxand disadvantagesare overcome-and.y largely eliminatedi'w-ithoutl introducing any additional problemsV or. increasing costs.

Another. object othe present invention is to provide an improved'pressin which itsstrokecan be regulated and adjusted at will to produce quick approach movements through. considerable lengthwith the exertion of` relatively light forces, andlmovements with developingexceedingly high forces through the remaining portions of thc workingstroke.

A further object of the present invention istoprovide apressvof the nature specilied'in-thepreceding paragraph, in which the lengths of theapproach movement andof the high pressure or working movement can, be selectively adjustedto suitI the particular requirements.

Astill further object offthe presentvinvention is to provide an improved press of the foregoing nature which-l is automatically locked-atfthe end-@fits high pressuremovement andxcan remain insuch locked'position for-any desired length` of time without the necessity of runningany pumps or motors'. for ymaintaining such pressure, which isanimportant advantage in plastic and rubber.A molding.

A still further object of thepresent invention isvto provide a press of thev foregoing nature, in which the approach movement offthe movable portion of the die or mold tothe work maybe performed manually while the high pressure movementsare power produced, or to have both types of movementsV produced manually or to have both types of movements power produced.

A stilhfurtherfobjectof. .theV present invention istto providean improved v.pl'essfof Ithe foregoing nature which can utilize.y hydraulic, pneumatic, electric, and other types of Apower, producing means.

A stillfurther objeCt'of-the present invention is to provide an improvedjpress which can be made to operate either as light force long stroke press only, or as a short stroke highforce press, withthe change inthe press being accomplished merely by actuating a control lever providedV thereon.

It'- is; anadded; object ofthe-present invention to provide an improyedpressof theforegoingnature which ,is simple andruggedin construction, safe anludependable in operation., and isinexpnsive t0 manufatural Further objects landadvautasgs of` this inventiomwll be apparent from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification, wherein like reference characters designate corresponding parts in the several views. i

Fig. 1 is a side view of a press embodying the present invention.

Fig. 2 is a front view of the press of Fig. 1 and showing its connection to another press for operating on the same workpiece.

Fig. 3 is an elevational view partly in section taken in the direction of the arrows on the section plane 3-3 of Fig. 2 and showing operative parts of the press in their positions corresponding to the uppermost position of the movable portion of the die.

Fig. 4 is a fragmentary view similar in part to Fig. 3 but showing the toggle linkage engaging the rack, and before the toggle linkage begins moving the rack downwardly.

Fig. 5 is a view similar in part to Fig. 4 but showing said linkage in its fully extended position, i. e. at the end of its operative movement.

Fig. 6 is a front view of the toggle linkage before the same moves down to exert high pressure on the racks through the comb block, i. e. corresponding to Fig. 4.

Fig. 7 is a view similar in part to Fig. 6 but illustrating said toggle linkage in its fully extended position, i. e. corresponding to Fig. 5. g

Fig. 8 is a fragmentary side view taken on the toggle linkage from the same direction as in Fig. 3.

Fig. 9 shows teeth on one of the racks and on the comb block, chamfered to prevent such teeth from meeting with their flat tops that could prevent their proper engagement.

Fig. 10 is a sectional view taken in the direction of the arrows on the section plane passing through the line 10-10 of Fig. 8.

Fig. l1 is a fragmentary view with portions broken away of the middle portion of the press shown in Fig. 2.

Fig. l2 is a perspective view showing the comb block and its engagement to the racks, with portions of the construction being broken away.

Fig. 13 is a diagrammatic view showing hydraulic means for operating the toggle linkage.

Fig. 14 is a plan view showing a combination of four press units for operating on a single workpiece.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

In accordance with the invention, I provide a press which combines within itself the advantages of both an arbor press and a toggle press, with the arbor press mechanism operating to move the movable portion of the die or mold through relatively long distances where application of only relatively light forces is required, such, for instance, as in approaches to work and withdrawal therefrom. However, for exerting high operation forces the arbor press mechanisms automatically engage the toggle mechanism to aid themselves, such engagement being effected not only automatically but also at a selectively predetermined portion of the working stroke of the press.

For average requirements, my improved press is constructed to have its arbor press mechanisms actuated manually for bringing the movable portion of the mold or die to the work, whereupon, upon automatic engagement of the toggle mechanism, the sam-e ispower operated for exerting high pressure forces on the workpiece. Operation and the stroke of the toggle linkage are so adjusted that in the position of the press when the highest force is to be exerted, which is usually at the end of the working movement of the movable portion of the die or mold, the toggle linkage comes to its dead center and, therefore, locks the movable portion of the die or mold in such a position and retains it therein for a predetermined period of time. The duration of such a period is controlled by a timing mechanism, which mechanism, upon the expiration of the prescribed period closes a switch, setting in motion the power means operating the toggle linkage for withdrawal of the movable portion of the die or mold. Thereupon, by the operation of the arbor press means, said movable portion may be withdrawn for a considerable distance to permit withdrawal of the workpiece. It will be understood, however, that, if desired, the arbor press mechanisms may also be power operated. Also, the arbor press mechanisms and the toggle mechanisms may both be operated manually. The power means may be of any suitable character, electric, hydraulic, pneumatic, and the like.

While the present invention has been illustrated and described with reference to a press utilizing toggle means for exerting high pressure forces, it will be understood that eccentric means and crank means can be substituted for toggle linkage and serve for the purposes of the present invention with success. It will also be understood that use of pneumatic or hydraulic means for long distance light force travel of the movable portion of the die or mold may also be substituted for arbor means, with the former means operating the controls setting toggle, eccentric or crank press means in operation for short distance high pressure travel of the movable portion of the die or mold.

Referring to the drawings, there is shown therein, by way of example, a group of presses adapted to operate together on a certain workpiece without the necessity of constructing a ram of a large size. The connection between the separate presses to ensure their operation will be described in detail below. Construction of all of the presses of the group may be identical or similar and, therefore, only one such unit needs to be described in detail.

Referring more specifically to the drawings, a unit press comprises a frame generally indicated by the numeral 15 and having a base 16 adapted to receive and support the lower or stationary portion 17 of the die or mold. In the hollow head of the press there are operatively mounted for vertical movements three racks 18, 19 and 20. The total stroke of the movable portion of the die or mold carried by said racks is designated in Fig. 1 by the letter t. The long distance light force portion of the total stroke is designated by the letter l, and the short distance heavy force portion of the total stroke is designated by the letter l1.

The racks 18, 19 and 20 are connected with the movable portion 21 of the die or mold through adjustable connections 18a, 19a and 20a. The racks 18 and 19 are engaged and are operated by gears 22 and 23, respectively, mounted on the same shaft and operating to move said racks 18 and 19 for electing long distance light force movements of the portion 21. The rack 20 is actuated by the racks 18 and 19 through gears 24a and 24!) mounted on a shaft 25 on which there are also mounted sprocket wheels 25a drivingly engaging through chain 25C similar sprockets 26a mounted on a shaft 26 and carrying a gear 27 engaging the rack 20. By virtue of such a construction, operative forces on the portion 21 are exerted not in the center or in one locality thereof but in three different places around its entire area, ensuring more even distribution of forces and stresses. Although in the present embodiment of the invention two racks are shown in front and one at the rear, different number and arrangement ofthe racks can be used to suit the particular conditions.

A counterweight 28 operating on the chain 28a.con-

fine rnia@ 4z knnen with yitvits shaft 32 and moying `the righthanden d ofthelver .l

and has. providedi 'OLthe ooxnbj Yblogk 43.1 'to thewleft would Canne the `cornb portions 48Q49, "and ySl V'to` engage the rak's' 18119lnd y A y,onn'ecrtedthrough toggleflinkage, including two pairs of links;k one 'of vSaid. corniiiisifig iiiiks 5,1, and` s2,` and ,ihvdihen `links 5% and'lSA, with g'arsSS` and f which are operated by a'worin 57 oianelet'ric motor 59,

infin i akin-g the *iiiikgg inevaisibn. jin ailier nbias, Vysli'en e toggle Ylinks assunte positinslsliyvnn Pig. 7,

iflyioe 78 which interfrn'up't the electric circuit of then motor V59I fa predetermined `period of Ytime and upon expirali'wn in Fig. fiorireneatinggfthe Cycle.

Yiith the construction descr'ibed' above," automatic VVen- Eox'ith""stationary'atucturefof the'lmacliine` and having connection of the racks 18',- 19`"nd 20""'lnioiiglr1 gears., l

d gtherefore, "operation of the toggle the lever 3,3 and disengagement of the vcornlybloclof from the `racks-18, 19A and' 20. It will Ibveunderstood of a' erank'80'whcli, ihk-turn, is` operted'fmm a coinm v 7 rod 81.. ,The rod 81 is passed through the frame of the `machine and is maintained in its uppermost position with 4the aid of a spring 82 supported by a bracket'83 and acting on an adjustable collar 84. The control rod 81 is, in turn, operated by the movable portion 21 of the die. It can be seen from examination of Fig. 3 that there is provided on the rod 81 a control collar 85 which may lbe adjustably secured on the rod 81 at a desired location along the length of said rod under the portion V21. As the portion 21 reaches theA control collar 85, further downward movement of the portion 21'causes downward movement of the vrod 81 in opposition to the action ofthe spring 82. In the process of such movement of the control rod 81, the collar 86 reaches the kfinger 87 and by rotating the crank 80 around its stationary axis 88 in the direction indicated by the arrow in Fig. 3 moves the cam block 70 and brings it into the position shown in Fig. 4. In the process of such movement the roller 71 presses downwardly the righthand end of the lever 33 and thus causes engagement of the arbor racks by the toggle linkage through the operation of the mechanisms described above.

As the toggle linkage moves the comb block 43 down, the stud 90 carried on the block 44 contacts the end 91 of the crank 80, rotating said crank and bringing 'it into the position shown in Fig. 5, and, therefore, returning the cam block 70 into its original position and permitting the righthand end of the lever 33 to move upwardly and to disconnect in the manner described above the comb block 43 from the racks. Thereupon, by manually operating the hand wheel 30 the movable portion 21 may be returned to its original position shown in Fig. 1.

A stop collar 89 may be provided on the rod 81 to restrict its upward movement. However, with a deiinite length of the spring 82, the collar 89 may not be necessary since the weight of the rod will keep it in its predetermined uppermost position. k

In accordance with the invention, there are provided locking means adapted to lock the gear block 40 selectively either in its upper or in its lower position. It will now be understood in view of the foregoing, that if'the gear block 40 is locked in its lower position, operation of the press will be that of a mere arbor press since no upward movement of the gear block 40 for engaging the toggle linkage to the racks can occur in the press. On the other hand, locking the gear :block 40 in its uppermost position will cause constant engagement of the toggle linkage to the racks 18, 19 and 20 and their actuation by the toggle linkage. Then operation of the press becomes that of a toggle press only, with the manual wheel 30 and the gears connected thereto rotating idly in response to the movements of the racks.

In the present invention, such locking means are exemplied by the pin 100 provided in the bracket 101 secured to the frame of the press. A compression spring 102 tends to maintainrthe pin 100 in its retracted position shown in Fig. 3, thus ensuring operation of the press as a combined arbor-and-toggle press. On the other hand, when the pin 100 is pushed to have its end enter the upper hole 103 provided in the gear block 40, and the pin is locked in that position by having its handle 100a turned 180 to have the eccentric 100b provided on the pin to bear on the shoulder 101a of the bracket 101, the gear block 40 will not move up and will not cause engagement of the toggle linkage to the racks. Therefore, under such a condition operation of the press through its entire stroke will be that of an arbor press. However, when the block 40 is moved into its uppermost position, and the pin 100 is made to engage it at the lower hole 104, operation of the press becomes that of :a toggle press with the length of its stroke being only that determined by the toggle linkage.

Fig. 13 illustrates a uid'cylinder 105 which may utilize CII either liquid, such as oil, or gas, such 'as air, for op- .75

erating the linkage comprising the links 106 and 107 for .operating the movable portion 21 of the die.

the shafts of the presses 110 and 111 are arranged "along a straight line and are connected together, with the shafts 116 of the presses 112 and 113 being similarly connected. Connection of shafts 115 and 116 is effected with the aid of miter gears and shafts 117 and 118. Operation of the control wheel 30 will thus operate all of the gear shafts of the presses and make vall of them operate together as arbor presses, bringing the toggle linkage in operation as described above. While there may be some torsional deilection in the shafts and play in the miter gears, the same does not aiect appreciably operation of the presses since such deflection would occur primarily in the arbor operation of the press. On the other hand, when the toggle linkages of the presses come into play, they act directly on each individual press.

By virtue of the above disclosed construction, the objects of the present invention listed above and numerous additional advantages are attained.

I claim:v

l. In a press, a longitudinal movable rack provided therein, a gear engaging' said rack and adapted, when rotated, to actuate said rack and to roll on said rack longitudinally thereof when said rack meets resistance of a predetermined magnitude; a toggle mechanism adapted to produce press operating forces, means adapted to interconnect drivingly said toggle mechanism and said rack, power means operating said toggle mechanism, cam means actuated by the bodily movements of said gear along the rack and adapted to operate the means interconnecting drivingly said toggle mechanism and said rack to cause driving engagement of the toggle mechanism to said rack, and to start said power means for operating said toggle mechanism.

2. In a press, a longitudinally movable rack provided therein, a gear engaging said rack and adapted when rotated to actuate said rack longitudinally and to roll on said rack and thus to move bodily longitudinally thereof `when said rack meets a resistance of a predetermined magnitude, a toothed member movable in and out of enladapted to exert operation forces on said toggle mechanism and thus to cause said toggle mechanism to move said toothed member for actuating said racks, and mechanical means operatively interposed between said gear and said toothed member and responsive to the bodily movements of said gear along said rack to move said toothed member in and out of engagement with said rack.

3. In a press, a longitudinally movable rack provided therein, a gear engaging said rack and adapted when rotated to actuate said rack longitudinally and to roll on said rack and thus to move bodily longitudinally thereof when said rack meets a resistance of a predetermined magnitude, a toothed member movable in and out of engagement with said rack and to move bodily for actuating the same, a toggle mechanism operatively connected to said member to exert operation forces thereon, manual means for rotating said gear vin operating of the press, power means operating said toggle mechanism to move said toothed member bodilyfor actuating said racks, and mechanical means operatively interposed between said gear and said toothed member and responsive to the bodily movements of said gear along said rack to move said toothed member in and out of engagement with said rack, and control means responsive to the movement of said mechanical means and adapted to start said power means when said toothed member is moved into engagement with said rack.

V4. .1n a press, a longitudinally movable rack provided therein, a gear engaging said rack and adapted when rotated to actuate said rack and to roll on said rack and thus to move bodily longitudinally thereof when said rack meets a resistance of a predetermined magnitude, a toothed member mo-vable in and out of engagement with said rack and to move bodily to actuate the same, a toggle mechanism operatively connected to said member to exert operation forces thereon, manual means for rotating said gear in operating the press, an electric motor adapted to operate said toggle mechanism to cause said toggle mechanism to move said toothed member .for actuating said racks, and mechanical means operatively interposed between said gear and said toothed member and responive to the bodily movements of said gear along said rack to move said toothed member in and out of engagement with said rack, and a switch operated by said mechanical means, when said toothed member is moved into engagement with said rack, to switch said motor on.

5. The press defined by claim l and including yielding means associated with the gear and determining the amount of minimum resistance at which the gear begins to roll along the rack.

6. The press defined by claim 1 and including a spring of a predetermined rate and resisting bodily movement of the gear along the rack and thus determining the minimum resistance at which the gear begins to roll on the rack.

7. in a press having an operating device including a stationary portion and a movable portion, a rack carrying the movable portion of the operating device, a gear engaging said rack and moving the same longitudinally when rotated, said gear being adapted to roll on said rack for a predetermined distance when said rack meets a resistance of predetermined magnitude, a toothed block adapted to move in and out of engagement with said rack, a toggle mechanism operatively connected to said block to exert operation forces thereon, power means for actuating said toggle mechanism, cam means, a slide engaging said cam means and acting on said block to move it in and out of engagement with said rack and adapted to be actuated by the movement of the gear along the rack.

8. The invention defined-in claim 7, and including selectively operable means to lock said gear at least in one of its extreme positions of bodily movements along the rack.

9. The invention defined in claim 7, and including selectively operable means to lock said gear at either of the t 10 twokextreme positions of its bodily movements along the rac l0. The invention delined by claim 7 and including adjustable rod-and-collar means actuated by the movable portion of the press for controlling occurrence of the engagement of the rack by said toothed block.

1l. In a press, a rack, a gear engaging said rack and moving the same longitudinally when rotated, said gear being adapted to roll along said rack for a predetermined distance when said rack meets in its longitudinal movement a resistance of predetermined magnitude, a support for said gear movable bodily along said rack when the gear rolls along the rack, toothed means adapted to engage said rack for moving the same and to be disengaged therefrom, toggle mechanism acting on said toothed means to actuate the same for moving said rack, power means operating said toggle mechanism, control means adapted to switch on said power means, and movable means intermediate said gear support and said toothed means and adapted to actuate said control means to switch the power means on after said tooth means are moved into engagement with said rack.

l2. In a press having a movable portion, a plurality of racks secured to said portion at spaced localities to exert pressure thereon at said localities, a gear for each of said racks, each of said gears being adapted, when rotated, to actuate its respective rack but to roll along said rack when the movable portion meets resistance greater than a pre determined minimum, means drivingly interconnecting said gears, a toothed block adapted to be moved in and out of engagement with each of said racks simultaneously, a toggle mechanism adapted to exert pressure on said racks through said toothed block, cam means operatively interposed between at least one of said gears and said block and adapted to move said blo-ck into engagement` References Cited in the file of this patent UNITED STATES PATENTS 2,572,286 Smith Oct. 23, 1951

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