US1368366A - Drawing-press - Google Patents

Description

R. S. SMITH. DRAWING PRESS. APPLICATION FILED III/III` a. I92o,

UNITED STATES PATENT OFFICE.

DRAWING-PRESS..

Speciicaton of Letters Patent.

Patented Feb. 15, 1921.

Original application led July 16, 1917, Serial No. 180,758. Divided and this application led March 8,

` 19.20. Serial No. 363,957.

To all whom t may cof/wem:

Be it known that I, REUBEN STANLEY SMrrH, a citizen of the United States, and a resident of the cit of Milwaukee, county of Milwaukee, and tate of Wisconsin,r have invented certain new and useful Improvements in Drawing-Presses; and I do declare the following to be a full, clear, and exact description thereof, such as will enable others skilled in the art to which my invention pertains to make and use the same, ref erence being had to the accompanying drawings for a disclosure of one construction in which the invention has been embodied.

The subject matter of the present application has been divided out of my prior application, Serial `:,.[:150,758, filed July 16, 1917, since matured into Patent No. 1,338,335, April 27, 1920, to which patent reference may be had for a disclosure -of the generic aspects of my invention.

The invention relates to drawing presses which are em loyed for the urpose of producing shape articles from I'Iat metal sheets. In articular,` the drawing press may be use in the production of the side bars yof an automobile frame, which, as is well known, are formed from sheet metal and have the formation of a channel bar, but the press .for the purposes of this application to say that the press is provided with an eccentric mechanism which is actuated in proper timing so as to move the unch to clamp the metal plate between t e punch and the knock-out plate usually employed in drawing presses, and which in my press, stands normally flush with the top of the matrix, and that at or near the termination of such clamping movement, a second set of eccentrics is actuated so as to continue the movement of the punch to force the clamped plate into the matrix of the press and perform the drawing operation upon the plate, whereby the desired shape is imparted to the article formed from the said plate.

The eccentric mechanisms referred to are separately controlled in their action by a.

timing mechanism, as disclosed in the said patent, so that the clamping action upon the metal plate is effected with rapidity of move-A ment of the punch, which clamping action 1s followed immediately by the retarded voperatlon of the eccentric mechanism which imparts further movement tov the punch to perform the drawing operation.

The surface of the bed of the press is formed as a smooth topped table, over which the plates may be manipulated without the interference heretofore encountered in drawing presses, by reason of mounting the matrix `and its adjunctive devices above the plane of the bed of the press. To enable me to carry out the plan just described, I provide a longitudinal channel in the bed of the press, and in such channel I place the matrix, which, with the punch above referred to, constitute the die members of the press. In drawlng presses as heretofore constructed, the matrix has been fitted in a shoe, which is attached to the bed of the press. It has been required in such presses that the shoe referred to be of such proportions and strength as to enable it to resist the lateral stresses encountered in the operation of the press, and also that the sole of the shoe be of sufficient thickness, together with the bed upon which the shoe is placed, to withstand any tendency to fracture under the crushing strains. But in my improved press the bed in which the' channel for the matrix is formed is so proportioned that all of the strains incident to the operation of the presses of ordinary common construction are effectively resisted and the causes for complaint are eliminated. I achieve this result by giving the bed of the press a formation, which in cross-section resembles the letter C, when partly turned, and which possesses the highest elements of rigidity.

The knock-out plate is normally sustained so as to be flush with the top of the matrix, but such knock-out plate is actuated so as to retire within the matrix at a' ratewof speed which is coincident with the descrlbed further advancing movement of the punch, f ollowing the clamping operation, and durmg which further movement the drawing operation upon the metal plateis performed, but the clamping relation between the punch and theknock-out plate is maintained-during the drawing operation.

In presses in which the side members of vthe matrixbare immovable or fixed with relation each other, it sometimes happens that inequalities existingkin the metal sheet ""to *beV drawn, will lmpose very severe strains der such conditions, compression of the metal y, forming the sides of the channel bar takes place betweenthe punch and the side members of the matrix, and the resistance thus interposed sometimes results in disaster to the ress.

ith a view to relieving the press from the unusual strains which are exerted under the exigencies described, I have constructed the .Said matrix so that the side members thereof may have capacity for limited movement toward each other, such side members being actuated at or near the termination f of',v the drawing movement of the punch. In

carrying out this feature of my invention, I arrange the said side members of the matrixso as to provide a slight clearance.y

between the matrix and the metal sheet as the punch forces the latter into the matrix, thus permitting the metal plate to be drawn without the expenditure of more than the power required to operate the press under normal conditions. Through properly positioned actuating devices, I move the side members of the matrix toward each other so as to exert a great pressure with but little consumption of power, and squeeze the flanges of the drawn bar into contact with the sides of the punch, and thus complete the formation of the said bar by 'giving a permanent set to said anges. The provisions described enable me to obviate the dif# iculti'es heretofore referred to, and to complete the drawn article without the use of the excessive force incident to the operation of the older types of drawing presses.

To impart lateral movement to the side members of the matrix, I employ a crank mechanism which, with the consumption of a small amount of power, will actuate a toggle mechanism to exertv the necessary degree of pressure upon the side members of the matrix and move them so as to impart the desired squeezing pressure upon the side fianges of the channel bar which has been formed from the blank in the matrix.

As in my said patent, the further movement of the punch to perform the drawing operation is transmitted through the devices which -have previously brought the punch into clamping relation with the metal plate to be drawn into shape. That is to say, when the eccentric mechanism for effecting the clamping movement has completed its operation, the eccentrics for effecting the drawing operation impart a further movement to the punch by bodily moving the first orY clamping eccentric mechanism.

Another feature embodied in my present invention is one wherein the -main operating parts, including the gears and the several Hoor line with reference to which the press is set. A11 advantage which follows from this arrangement is that it enable's me to construct a press which is accessible from all sides, without any interference by reason of the presence of the shafts and gears at the sides and ends of the press, as heretofore.

Another advantage resulting from the construction just referred to, is that I am enabled to maintain a constant shower of oil upon the several actuating and operating mechanisms, and so provide an efficient means for lubricating the parts. The oil which drips from the several mechanisms lmay be collected and filtered, and again used for lubrication.

In the drawings which accompany this specification,

Figure 1 is an end view showing in general outline the construction of press illustrated in my above mentioned application.

Fig. 2 is a sectional view through one side of the bed and matrix, showing in enlarged detail, one of the toggle mechanisms employed to impart lateral movement ,tothe side members of the matrix, to effect the side squeezing operation described,

In the drawings, A indicates the main frame of the press, which may be integrally formed, or it may be constituted of frame sections which will be so secured together as to form a unitary structure. The base of this press will rest at the bottom of a pit of suitable dimensions, and the driving shafts and gears a-nd eccentric mechanisms will be placed entirely below the iioor line at the top of the pit, and with relation to which the press is set, so as to render the press accessible from all sides without interrup tion or interference. This arrangement further enables me to maintain a constant shower of oil either in the form of a spray, or in the form of streams directed upon particular parts, so as to effect an eiiicient lubrication of the parts, which in their operation are subject to considerable friction, by reason of the severe stresses occurring in the press. To be able to lubricate the mechanism of the press in the manner described, is advantageous in that it eliminates the labor of periodic lubrication and further protects the press against neglect in this important particulanvwum Surmounting the main frame, is the bed B of the press, which bed is channeled longitudinally as-indicated at b, for the recep tion of the matrix side members C, C1. In the construction illustrated, I have shown the said matrix members as supported upon angular carriers D, D1, in vthe angles of which the respective matrix members C, C1,

-which cross head is mounted upon the upper ends of straining rods e, which latter are guided in vertical openings in the bed of the press. A sliding cross head E2 is connected to the lower ends of the straining rods e. The cross heads E1 and E2, and the straining rods e, constitute a punch carrying frame, which is movable as a whole. The lower cross-head E2 is guided in the sides of the main frame, so that the punch carrying frame may have a vertical reciprocation in a fixed path.

A second frame, composed of an upper` cross head F, a lower cross head F1, and straining rodsf, connecting the cross heads F and F1, is also guided for vertical recipro-- cation iIi the frame of the press, and is'likewise movable as a whole. The straining rods E of the punch carrying frame pass through openings in the cross head F of the lower frame, and the straining rods f of the lower frame pass throu h cross head E2 of ne punch carrying frame. While-the said frames are each capable of independent movement, they have a joint movement at times, as will be described later. v

The straining rods e, e, uniting the cross-y heads E1, E2, as well as the straining rods f, f, uniting the crossfheads F, F1, are threaded at theirends for the reception of huts, which bear upon the upper and lower sides of the respective cross-heads, so as to provide an exact adjustment of the punch E with reference to the matrix of the press,

and correspondingly define the movements of the punchunder the influence of the eccentrics.

The driving shaft G is journaled at one side of the frame and carries a pinion g meshing with a gear g1, 'upon the axis of which is fixed a pinion g2, meshing with a gear g3 which latter carries a pinion g". Upon the axis of the gear g3 and pinion g4. a radial arm g5 is mounted, the said arm supporting at its outer end a stud ge, upon which rotates a gear 97, in mesh with the pinion g2 previously described. A floating lever g2 is supported upon the stud g", and extends to the exterior of the press. At its inner end, the fioating lever supports an eccentric shaft g1 j ournaled in the cross head F, of the lower frame.

Keyed upon the eccentric shaft is a gear g10 which meshes with an idl'e gear 911 carried by the ioating lever and in mesh with the gear g7. Through the connections described, motion is transmitted from the driving shaft to the eccentric shaft, The

openings in the lowertrain of gears will be duplicated at the other end of the press, and connected by suitable shafting. Several eccentrics, one of which, indicated g12, are mounted on the eccentric shaft g, and are connected by eccentric links g, to the lower cross heads e2 of the punch carrying frame.

The surface of the bed B is formed' as a smooth topped table, free from projections.

The matrix members C and C1, and their supporting carriers D, D1, lie flush with the surface of the bed. A knock-out plate e1 is normally supported with its face iiush with that of the matrix, as shown in F ig.' 1. Knock-out pins e2, guided in vertical openings in the bed B, support the knock-out plate e1' at their upper ends, and the 'lower ends of the said knock-out pins rest upon a plane surface formed upon the top of the cross head F. In such position, the knockout pins e2 serve as thrust rods to maintain at all times a fixed distance between the knock-out plate e1 and the plane surface e1 of the cross head F.

The pinion g on the driving shaft G also meshes with a gea-r h, on the hubof which is fixed a pinion h1, meshing with a gear h3, which carries a pinion h2, which in turn meshes with a gear h5, mounted upon an ec-I centric shaft k6, journald in a fixed cross bar of the main frame. The eccentric shaft it is provided with eccentrics h1, which latter are connected by links ha, to the cross head F1 of the lower frame.

In the operation of the press, a metal blank w is ed intothe press and properly ioo positioned over the matrix.4 The speed of rotation of the eccentric shaft g2, is such that the eccentrics 912, carried thereby, impart a comparatively quick movement to the punch carrying frame to bring the punch'E into clamping relation with the blank resting upon the knock-out plate 1, and supported also upon the face of the matrix. This clamping relation is established as the eccentrics 912 reach the end of their throw. The reducing gears leading to the'eccentric shaft h are so proportioned that a relatively slowrmovement is imparted bv the eccentrics h1 to the drawing frame. Just as the eccentrics g12 completetheir throw, the eccentrics h1 commence their operation, and ltransmit a further 'but retarded movement to the punch carrying frame through the now distended eccentric links g, the shaft g, and the lower cross bar E2 of the punch carrying frame. During the downward stroke of the eccentrics h", the punch carrying frame and the drawing frame move jointly as a single construction, whereby the punch in its further movement intoy vthe matrix under the action of the eccentrics h1, forces the metal blank m into the matrix, and folds the sides thereof against the sides of the punch so as to form the said metal blank into a channel bar.

From the time that the punch has reached its position of clamping relation with the blank and the knock-out plate e1, the said relation does not change until after the drawing operation has been performed. The punch E and the cross head F move at the same relative speed during the drawing operation, and the knock-out platee1 being sustained by the knock-out rods, the blank m is rmly clamped between the punch and the knock-out plate e1 during the whole of the drawing operation. The advance of the punch AE to force the blank into the matrix, is accompanied by the simultaneous retirement of the knock-out plate e1, by reason of the movement of the cross head F under the action of the eccentrics 7L7,.and when the latter have passed their dead center, the withdrawal of the punch will be closely followed bythe movement of the knock-out plate e1, to ejectthe channel bar from the matrix. The clamping relation between the punch and the knock-out plate is broken at the moment that the knock-out plate reaches its normal elevated position in line with the face of the bed, and the punch is raised to its highest position by reason of the eccentrics g12 havmg passed their dead center on their longer throw, and through their connected straps g13 are acting to lift the punch carrying frame. 'l

In ldrawing presses as usually constructed heretofore, a singleset of eccentrics or crank mechanism has been used to impart both clamping movement and the drawing movement to the punch. In such older mechanism, the punch effect-s its clamping 'engagement with the metal blank at a time of comparatively rapid movement ofthe punch, with the result that the punch forces the metal blank into the matrix with a sudden blow, which occurs with such force and rapidity that time is not allowed for the necessary molecular changes in the structure of the metal to take place,l and this frequently is productive of an uneven or unequal distortion which weakens the bar along the line of the bend. But in my approved press, the compound motion which employ enables me to effect the clamping action upon the blank with rapidity, and to instantly start the drawing operation at its lowest relative speed. The result of the operation of my press is that at the commencement of the drawing operation, the molecular construction of the metal blank has an opportunity to adjust itself to the change` so that the drawing operation may be performed upon theblank and so obviate the liability to the damage heretofore usually incurred. As indicated at the beginning of this specification, it sometimes happens that inequalities inthe metal blanks impose severe strains upon the construction of the press when the punch starts to force the blank into the matrix. Such contingencies require the expenditure of more than the power required to operate the press under normal conditions, and disaster to the press sometimes results. VI have found that by constructing the press so that the side members of the matrix are disposed at a distance from the punch a little in excess of the thickness of the blank to be drawn, that the punch may force the metal blank into the matrix with no unusual effort, and that by providing means for taking up the clearance by constructing the side members of the matrix with capacity for movement toward each other, the sides of the drawn bar may be squeezed against the sides of the punch, to complete the formation of such bar.

To enable me to perform this operation of exerting a side pressure on the flanges of the channel bar, I have mounted a pair of longitudinal shafts H, H1,.in the bed of the press, and have fixed upon the said shafts a series of cams or toggle members 7L1, which are adapted upon the partial rotation of the said shafts, to impart their thrust to other toggle members 7&11, which bear against sliding blocks k12 mounted in channels 71,13 in the bed of the press. The sliding blocks k12 abut directly against the matrix members C and C1, or against the carriers D and D1, in case the latter are employed to support the matrix members.

The parts described are operated for the purpose stated, at the conclusion of the drawing movement of the punch, and act to compress the flanges of the channel bar between the punch and the matrix members, whereby a permanent set is given to the said flanges. This squeezing motion is followed by a quick relaxation of the pressure, and leaves the withdrawal of the punch and the ejection of the channel bar from the matrix to be performed freely, and without having to overcome the frictional resistance existing between the punch, the blank and the matrix in drawing presses of the older type.

I have provided a simple means for effecting the lateral movement of the matrix members just described. The rock shafts H and H1, are provided with radial levers 7L14 and 71,15 connected at their ends by a toggle 7L, which latter is operated by a link 7L17 connected at its" other end to one arm of a bell crank lever 71,18, the other arm of which is connected by means of a rod 7t19 to a. crank 7L20 mounted axially with a gear 7a11 driven 'by a pinion M2, fixed on the driving shaft G before referred to.

It will be observed that the' bed of the press has in cross-section the general outline of a letter C, turned on its axis.

The proportions embodied in the formation of the bed of the press are such that the opposing strains are resisted much more eifectively than in the common types of similar presses, in which the matrix is set in a shoe which is mounted upon the bed of the press, and over which 'the work must be lifted.

Having thus described my invention, what I claim and desir@l to secure by Letters Patent ofthe United States, is:

1. In a drawing press, the combination with a set of coperative work shaping members, of crank motion mechanism adapted to effect a relative approach of said members for one operation, and separately acting crank motion mechanism adapted to impart a further movement of said members in the same direction for a second operation, one of said members being formed in laterally movable sections, and means for imparting relative movement of said sections towardy each other subsequent to the appreaching movements of said members.

2. In a drawing press, the combination with a matrix provided with laterally movable side walls, a knock out plate normally supported between the upper margins of said side walls, a punch motion mechanism adapted to actuate .said punch into work clamping position with reference to the knock out plate, separately acting crank motion mechanism for additionally actuating said punch and also the knock out plate toward the base of the matrix for a work shaping operation, means for subsequently moving said matrix walls toward each other to press the work upon;the sides of said punch, and means Jfor retracting said side walls and subsequently retracting the punch and the knock out plate to their initial positions.

i the knock out plate, separately acting crank. v

3. In a drawing press, the combination with a matrix provided with laterally movable side walls, a knock out plate normally supported between the upper margins of said side walls, a punch, crank motion mechanism adapted to actuate said punch into work clamping position with reference to motion mechanism for additionally actuating said punchl and also the knock out plate toward the base of the matrix for a work shaping operation, toggle mechanism for subsequently moving said matrix walls toward each other to `press the workupon the sides of said punch, and means forretracting said side walls and subsequently retracting thev punch and the knock out plate to their with a relatively stationary matrix having initial positions.

4. In a drawing press, the combination with a matrix provided with laterally movable side walls, a knock out plate normally supported between the upper margins of said side walls, a punch, crank motion mechanism adapted to actu-ate said punch into work clamping position with reference to the knock out plate, separately acting crank motion mechanism for additionally actuating said unch and also the knock out plate toward t e base of the matrix for a w'ork shaping operation, toggle mechanism for subsequently moving said matrix walls toward each other rto press the work upon the sides of said punch, means for retracting said side walls and subsequently retracting the punch and the'knockeout plate to their initial positions, and meansfor automati-- cally initiating the work clamping, work shaping, pressing, and retracting operations in sequence.

5. In a metal working press, a frame supporting a fixed bed at the top thereof and extending below the floor line above which the bed is located, a head reciprocating over the bed, straining rods connected to the head and guided for vertical movement by the bed, a driving shaft with eccentric connections to the straining rods to actua-te the said head, said shaft and connections being supported in -the frame below the floor line, so as' to afford unobstructed access to the press from all sides, and enable rthe actuating mechanism tobe lubricated by an oil spray.

6. In a drawing press, a reciprocating punch, a iixed bed having a channel in which the matrix is set tot form a flush-top workv table, movable sides for the matrix, and devices within the bed for actuating the said movable sides, to supplement the punch and matrix in shaping the work.

7. In a drawing press, the combination with a relatively stationary divided matrix having side walls adapted to approach and recede from each other, a punch, means for actuating the punch linto the matrix for a work shapin operation, and means for-actuating the side walls of the matrix toward each other upon completion of the work shaping operations of the punch.

8. In a drawing press, they combination with a relatively stationary divided matrix having side wallsadapted to approach and recede from each other, a punch, means Jfor actuating the punch into the matrix for a work shaping operation, and means for actuating the side walls of the matrix toward each other. upon completion of the work shaping operation yof the punch, said side walls being held in a relatively fixed position during the work shaping operation of' the punch.

9. In a drawing press, the combination 10. In a drawing press, the combination of a set of cooperating Work shaping members, mechanism adapted to effect a lrelative approach of said members for one operation, separately lacting mechanism adapted to produce a further relative movement of said members for a second operation, one of said members being formed in laterally movable sections, and means for moving said sections toward eachother upon the completion of the said second movement of' the work shaping members.

11. In a press for drawing metal plates into shape, a frame, a punch and a matrix, a bed forming a work table supported o-n the top of the frame, means comprising gears and eccentrics for actuating the punch arranged and connected thereto below the floor line with reference to which the press is located, whereby the bed is rendered accessible from all sides without obstruction by said actuating means, and whereby such floor line with reference to which the press is set, a punch working over the bed, a punch carrying frame guided by the bed and extending below the floor line, and actuating mechanism for vertically moving the punch carrying frame, said mechanism being positioned below the said floor line, whereby the bed of the -press is accessible at all sides Iand lubrication of the punch actu,- ating mechanism may be effected by an oil spray.

13. In a drawing press, a punch, a fixed bed having a channel in which the matrix is set to form a smooth topped table over which the work may be moved, said matrix composed of movable side members, and means for actuating the matrix members to supplement the action of the punch in shapin the work.

n testimony whereof, I have signed my name at Milwaukee, this 3d day of March, 1920.

R. STANLEY SMITH.

Witnesses:

W. F. WooLARD, C. THEO. Osrnnnns.V

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