US738335A - Drawing-press. - Google Patents

Description

PATENTED SEPT. 8, 1903..

P. M. LBAVITT.'

DRAWING PRESS.

APPLIQATION FILED JUNE 16, 1902.

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PATBNTBD SEPT. 3, 1903.

` P. M. LBAVITT.

DRAWING PRESS.

APPLICATION FILED JUNIllS, 1902. NO MODEL. 5 SHEETS-SHEET 2.

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No. 738,335. l PATENTED s:.l fr.s,19os.

f2 M. LDAVITT.

DRAWING PRESS.

APPLIGATION FILED .umn 16'. 1962.

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DRAWING rnss.

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No MODEL.

PATENTED SEPT. 8, 1903.

F. M. LEAVITT. DRAWING PRESS.

APPLICATION FILED JUNE 16, 1902.

5 SHEETS-SHEET 54.

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UNITED STATESY Patented September 8, 1905i.

PATENT OFFICE..

FRANK M. LEAVITT, OF BROOKLYN, NEW YORK, ASSIGNOR TO E. lV. .BLISS COMPANY, OF BROOKLYN, NEV YORK, A CORPORATION 'OF WEST VIRGINIA.

DRAWING-PRESS.

SPECIFICATION forming' part of Letters Patent No. 738,335, dated September 8, 1903.

Application filed June 16, 1902. Serial No. 111,859. (No modali.'

T0 @ZZ whom it may concern.'

Be it known that l, FRANK M. LEAVITT, a citizen of the United States, residing in the borough of Brooklyn, county of Kings, city and State of New York, have invented certain new and useful Improvements in Drawing- Presses, of which the following is a specification.

This invention relates to drawing-presses for drawing sheet metal or metal plates into cup-shaped articles. Such presses require an annular blank-holder for pinching the rim portion of the blank with a suitably-graduated pressure and a punch or male die movable through the blank-holder for forcing the central portion of the blank into cup shape and drawing the metal between the blankholding surfaces. Two types of such presses are commonly used, namely: first, the American type, where the bed or lower die is stationary and the blank-holder descends from above upon it, while the punch also descends from above through the blank-holder and through the female die, and,second, the German type, where the blank-holder is stationary and the female die is mounted upon a bed or platen which moves up from beneath to clamp the blank against the blank-holder, while the punch comes down from above through the blank-holder and into the female die to draw the blank. In either type of press the punch is driven continuously, or practically so, so that for each drawing operation occupying a time represented by three hundred and sixty degrees the punch is in motion during the whole of this time, while the blank holding or clamping part moves intermittently, moving toclamp the blank during about sixty degrees, then remaining stationary to hold the blank during about one hundred and twenty degrees, and then moving back to separate the blank-holding members during about sixty degrees, and again remaining stationary for about one hundred and twenty degrees to `give time for feeding on a new blank. To provide for these intermittent movements in drawingpresses of large size has involved serious practical difficulties, which it is the aim of my invention to overcome.

My invention is applied, preferably, to the German type of press, wherein the scr-called blank-holding or upper member is stationary and the lower member or die is given a vertical movement by being mounted upon a movable bed or platen.

According to my invention I provide any suitable means driven directly or otherwise from any suitable motor 'or prime mover for imparting suitable motion, preferably continuous,to the punch,and I provide an independent and intermittently-operating motor or prime mover for imparting the intermittent rising and falling movements to the bed or platen, this motor being controlled by the movements of the punch or the punch-driving mechanism, so that at predetermined lpoints in the movement of the punch it is started to cause the. bed to ascend or descend and is stopped automatically at the end of each ascending or descending movement.

In the preferred embodiment of my invention I provide the drawing-press with two direct-connected motors, which may be steamengines, gas-engines, or the like, or theymay be electromotors. One of them drives the punch and preferably runs continuously or until stopped by the operator, although it is within my invention to have the punch stopped vautomatically at the end of each complete drawing operation. The other motor runs intermittently, being stopped when the punch is at or near the upper end of its stroke in order to raise the bed and clamp the blank, whereu pon the motoris automatically stopped to cause the bed to dwell during the period of the draw, after which and at or about the time the punch reaches the lower extremity `of its stroke the beddriving motor is again -started in order to lower the bed, being again automatically stopped at the completion of the beds descending movement in order that the bed shall dwellduring the time required for removing the nished blank and feeding on a new one. The starting and stopping of the intermittent motor may be accomplished by suitable cams or tappets operated, respectively, by the punch or punch-driving mechanism and by the bed or bed-driving mechanism for starting and stopping the motel', respectively.

Having thus explained the nature of my inments of the bed and punch.

vention, I will proceed to describe one suitable embodiment thereof with reference to the accompanying drawings, Wherein-.

Figure 1 is a side elevation. Fig. 2 is a front elevation, partly in vertical section. Fig. 3 is a vertical mid-section viewed from the rsame sideas Fig. 1. Fig. 4 is a front View, in vertical section, taken on the line 4 4 in Figs. l and 3. Fig. 5 is a horizontal section cut approximately on the line 5 5 in Fig. 2. Fig. 6 is a diagram showing the relative move- Fig. 7 is a detail of one of the cams.

Referring to the drawings, let A designate any suitable main frame, preferably upright, and consisting in the construction shown of two upright side frames connected by fixed' cross-pieces A' at the base and A2 at the top, with an intermediate cross piece or head B, which is normally stationary, but is vertically adjustable by means of threaded portions engaged bythe threads on bolts a, connecting it to the cross-piece A2. A vertically-movable slide or plunger C is mounted to move through the open or hollow central portion of the cross-head B. A lower crosspiece D, constituting a movable bed or platen, is mounted to move vertically between the vertical side frames. The cross-pieces B and D carry, respectively, the clamping members for holding the blank. The upper blankholding member E is fastened to and beneath the cross-piece B, while the lower blank-holding member F is fastened on top of the movable VbedD. The upper one being stationary, the lower one rises and falls with the movements of the bed D to clamp or release the blank. The male die or punch G is fastened beneath the plunger() and works through the blank-holding members E F, the latter of which constitutes, as usual, the female die.

The vertically-reciprocating plunger C,with

its punch G, may be moved by any mechan-` ism known in the art or applicable to this purpose, being shown as operated by cranks 4on a main shaft H, carried in the lowei` part of the frame A, the cranks H H on its opposite ends being connected, through connecting rods or pitmen I I, to a cross frame or head C', which carries the plunger O. As the main shaftH is driven at uniform speed, a regular rising-.and-falling motion is thus imparted to the punch. The cross-head C is suitably guided between guides A3 on the upper part of the frame A. It is preferably stiifened by braces C2, (bestshown in Fig. 4,) connecting to a standard or pedestal (J3, resting on the middle ofthe cross-head C and within which the plunger C enters in such manner as to be vertically adjustable by means such as hereinafter described.

The bed D may be caused to ascend or descend by any known or suitable mechanism, it being preferable to employ mechanism acting on the principle of a toggle-joint. In the construction shown two parallel crank-shafts J J are extended horizontally beneath the bed, each shaft having two cranks JJ, which connect, through links or pitmen K K, with the bed D. The shafts J J are connected together to turn a half-revolution at a time simultaneously and at equal speed in opposite directions, whereby the cranks J J are carried from their lower to their upper dead-centers, or vice versa, at each operation. Each crank J and its pitman K constitute together a toggle-joint. When the toggles are straightened-that is to say, when the cranks are at their upper dead-centcrs-the bed is supported rigidly by the'four pitmen K K and cranks J J, each crank and its pitman being extended with their centers in alinernent.

It is necessary to provide suitable motors or sources of power, the one for giving continuous rotation during any desired period of time to the shaftH and the other for giving intermittent movement to the shafts J J', turning the latter through a half-revolution at each movement. For operating the shaft H, I have shown a motor or engine L, which is shown as a steam-engine, having its inlet at b and its exhaust at b. VThe starting and stopping of this engine may be controlled at will by any suitable means-as, for example, by means of a hand-lever c, suitably connected to its throttle-valve c' in any well-known manner. The engine L drives a crank-shaft d, having preferably a suitable fly-wheel, and which shaft through any suitable train of gearing drives the shaft H. I have shown the shaft d, having a pinion l, driving a gearwheel 2 on a shaft having a pinion 3, meshing with a gear 4 on a shaft having a gear 5, which meshes with and drivesa gear-wheel 6 on the shaft H. For driving the shafts J J the intermittently-operating engine or motor may turn them always in a uniform direction or may turn them alternately in forward and backward direction. To the toggle construction shown, which'admits ot' turning the shafts in the same direction throughout two successive half-revolutions, l prefer to apply motion always in one direction. To this end I drive them, through suitable gearing, from an engine or motor M, which is provided with any suitable means for starting and stopping it. This motor can be connected with the shafts J J through any suitable gearing, worm-gearing being preferable. Accordingly I have shown worm-wheels e e fixed on the respective shafts and driven by wormsff, fixed, on a shaft g, which is shown as being the crankshaft of the engine M.

The engine M is started and stopped in any suitable manner, soas to impart the rising and falling movements to the bed at the proper points in the travel of the punch, and it is also caused to run at such speed as will move the bed at a rate proportional to the rate of travel of the punch. Preferably the proportions of the respective movements are those indicated in the diagram Fig. G, where the sinusoidal curve denotes the reciprocating movement of the punch and the line IOO marked bed denotes the relative move-l ments of the bed. From thisdiagram it will be apparent that the bed starts from its lowest position at or just before the punch reaches the top of its stroke and rises rapidly to its highest position before the punch has descended to its level. In the diagram the lines in vertical projection represent the lowest point on the punch and a point on the die carried by the bed coinciding with the lowest part of the blank when in place upon the die.

sixty degrees in ascending and sixty degrees in descending, and it'is apparent from the diagram that it aseends and descends at a rate lnuch more rapid than the movement of the punch. Forstartingandstoppingthemotoror engine M at proper times for accomplishing these movements of the bed anysuitable mechanisms may be provided. I will proceed to describe one suitable means for attaining these results. It is characteristic of this means that the starting device is operated by some part in connection with the punch, and the stopping device is operated by some part in connection with the bed. In the case of a steamengine I provide a throttle-valve, which is opened by a cam or tappet device deriving motion from some part moving coincidently with the plunger and preferably from the main shaft H, and which is closed by a cam or tappet device operated by some part moving coincidently with the bed and preferably by one of the shafts J. I will proceed to de-l scribe this mechanism in detail.

On the shaft H is fixed a cam h, (best shown in Fig. 5,) which cam has two projections diametrically opposite to one another, so that at two points in each revolution of the shaft these projections shall act against a roller rl on a leverj to displace this lever and through it to impart motionr to a sliding rod 7c by means of a collar Zt', fixed thereon, against which the forked end of the lever acts, Whereby the rod is displaced in the direction ofthe arrows@ to open a throttle-valve Zin the steampipe Z', Fig. l, which supplies steam to the engine M. The exhaust-pipe from this cngine is shown at Z2. This opening of the throttle-Valve starts the engine,which through the shafts g and the worms .of the wormwheels drives the shafts J J through half a revolution. The throttle-,valve is held open,

so that the engine shall continu'e to run after the cam projection has passed the roller fr', and to this end the rod 7c is engaged by a dog or d etentp, which drops in behind a col- Accordingly the bed occupies, preferabiy, about lar k2 and holds therod in its displaced position against the tension of a spring s. The dog p is shown as an elbow-lever acted on by a spring q. The engine is stopped by the action of a cam 'm on one of the shafts J', which cam is shown in detail in Fig. 7. This cam has two projections at diametrically opposite points, so that at the end of each half-revolution one of these projections acts upon a roller n, Fig. 5, carried on or connected to the lever or dog p. The movement thus imparted to this roller displaces the dog and releases the rod 7c, which is immediately pressed by the springs in the direction of the arrow'y, whereby it closes the throttle Z and shuts off the steam, and consequently stops the engine. The engine then remains inert until again started by the next operation of the cam h.

Thus the cams Zt and m operate alternately and at suitable intervals of time to start and stop the engine M.

Obviously my invention may be applied in connection with other intermediate mechanisms for raising or lowering the bed from the engine or motor M. Obviously also any other suitable motor than a steam-engine may be applied, it being only necessary to vary the controlling mechanism so as to suitably adapt it to such other form of motor as will be well understood by those skilled in the engineering arts. For example, an electromotor may be used in place of the engine M, in which case `instead of being controlled by a throttle-valve anysuitable motor-starting box may be used, and this may be operated by the longitudinal movements of the sliding rod Zt, already decribed,or suitable movements may be otherwise imparted, as may be desired, it being understood that the details of my invention may be widely modified according to the judgment or skill of the engineer or constructor and according to the particular means employed for applying or transmitting power.

For enabling the plunger C to be adjusted vertically with reference to the cross-head C', I construct it to be capable of sliding within the cross-head and its pedestal C3, and I provide means for adjusting it vertically, consisting of a screw r, having bearings in the head r of the pedestal and having on its upper end a gear-wheel t, which may be turned by means of a hand-wheel zo, suitably geared to it, as by miter-gears u and a pinion '0, which latter gears with the Wheel t.

It is desirable to counterbalance the bed D, and to this end I provide it with pluugers or rams w, which enter hydraulic cylinders w', in which liquid is maintained under pressure sufficient to impart an upward thrust to the plungers substantially equivalent to the weight of the bed. The hydraulic pressure in the cylinders tu is maintained by means of any suitable accumulator, as will be understood by any engineer.

In order to expel the drawn blank from the female die F, I may provide the usual pushout pad or knocker l), supported on a post IOO IOS

IIO

P in any suitable iixed part of the base of the press, and which passes freely through a hole in the bed D, so that as the bed descends the blank is stopped against this pad and is thereby pushed out of the die.

My present invention is one species or modification forming part of a generic invention set forth and claimed in another application tiled by me .Tune 16,1902, Serial No. 111,860. In that application I have illustrated as the specific embodiment of my generic invention a single source of power for driving both the punch and bed, with means for connecting the bed-operating mechanism to such source of power for raising and lowering the bed and then disconnecting the same therefrom. My present invention differs from that species in that a distinct source of power is applied for driving the bed, being started and stopped at the beginning and end of each movement of the bed.

My invention is not necessarily limited to a drawing-press of the German type or one in which the upper blank-holding member is stationary and the lower one is mounted on a rising and falling bed, since it is applicable, although with less advantage, to presses of the American type, where the lower blankholding member is fixedly mounted and the upper member is carried by a moving part.

' As applied to the latter class of presses the moving part carrying such upper member becomes the equivalent of the movable bed of the press herein described.

What I claim is- 1. In a drawing-press the combination with means for reciprocating the punch, of an independent motor for driving the blank-holding mechanisms and means for starting and stopping such motor to cause the blank to be gripped and released at prescribed points in the movement of the punch.

2. In a drawing-press the combination with a reciprocating punch and a movable blankholding bed, of a motor adapted to operate continuously to drive the punch, an intermittently-operating motor for driving the bed,and means for starting and stopping such motor to cause the blank to be gripped and released at prescribed points in the movement of the punch.

3. In a drawing-press the combination with means for reciprocating the punch, of an independent motor for raising and lowering the movable bed, and means operated by the punch-reciprocating means for starting such motor at prescribed points in the travel of the punch.

4. In a drawing-press the combination with means for reciprocating the punch, of an independent motor for raising and lowering the movable bed, means operated by the punchreciprocating means for starting such motor at prescribed pointsin the travel ofthe punch, and means in connection with the bed for stopping the same at the end of each ascend'- ing or descending movement of the bed.

5. In a drawing-press,the combination with means for reciprocating the punch, of an independent motor for driving the blank-holding mechanism, and means for moving the blank-holding mechanism to its active position for clamping the blank, causing such mechanism to dwell in such position during the operation of the punch, -retracting such mechanism after the drawing operation and causing it to dwell in its inactive position.

6. 1n a drawing-press the combination with means for reciprocatingthe punch and mechanism for raising and lowering the movable bed, ot an independent motor for driving said bed-operating mechanism, a controlling device for said motor, a cam projection in connection with the punch-operating mechanism adapted at prescribed points in the travel of the punch to displace such controlling device and start the motor, and a cam projection in connection with the bed-operating mechanism adapted at prescribed points in the movement of the bed to displace said controlling device and stop the motor.

'7. In a drawing-press the combination with a reciprocating pu nch and a rotarycrank-shaft for reciprocating it, of mechanism for raising and lowering the movable bed, an independent motor for operating said mechanism, a

lcontrolling device for said motor, a cam on said crank-shaft for operating said controlling device to start the motor a-t prescribed points in the movement .of the punch, and a cam in connection with the bed-operating mechanism for displacing said controlling device to stop the motor at prescribed points inthe movement of the bed.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

FRANK M. LE AVITT.

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