US620659A - leavitt - Google Patents

Description

No. 620,659. Patented Mar. 7, I899.- F. M. LEAVITT.

PRESS FOR WORKING SHEET METAL.

(Application filed Apr. 15, 1898.) (No Model.) 3 Sheets-Sheet 2.

WW I I] WITNESSES: m INVENTOR:

$64 M 6 7 5/ 12s 1 zzomeys.

No. 620,659. Patented Mar. 7, I899. F. M. LEAVITT.

PRESS FOR WORKING SHEET METAL.

(Application filed Apr. 15, 1898.)

(No Model.) 3 Sheets'8heet 3.

dbcaxzfs. Ow

erated on.

UNITED STATES PATENT OFFICE.

FRANK M. LEAVITT, OF N E\V YORK, N. Y., ASSIGNOR TO THE E. WV. BLISS COMPANY, OF

SAME PLACE.

SPECIFICATION forming part of Letters Patent No. 620,659, dated March 7, 1899.

Application filed April 1 5, 1 8 98.

5 and State of New York, have invented certain new and useful Improvements in Presses for \Vorking Sheet Metal, &c., of which the following is a specification.

This invention relates to presses wherein IO the bed carrying the lower die is movable from a position under the upper die'to a position out of line therewith, in which latter position the operator removes the work and puts in place the new piece of work to be op- Such presses are used for stamping, punching, &c., and also for wiring sheetmetal goods-such as coffee-pots pails, buckets, &c.where the article to be operated on is of such height that to lift it out of (or off from) the lower die requires that the latter die shall be moved out of line with the upper die in order to avoid the necessity of giving the upper die an excessively long stroke. Hence in such wiring-presses it is customary to mount the lower die upon a sliding bed or table, which after the work is placed on or in the die is pushed forward by the operator until the lower die is brought into alinemeut with the upper one, whereupon the operator 3o presses the treadle which actuates the usual one-revolution clutch for engaging the normally-revolving driving-pulley with its shaft which works the vertically-sliding head, car rying the upper die, so that this die descends upon the lower die and then reascends and stops, whereupon the operator slides back the bed, lifts out or off the work, puts a new piece of work in place, and repeats the operation. Such :manualv operation of the slide is slow 0 and in large presses becomes seriously laborious. There is also danger that the operator may prematurely release the clutch, so as to bring the upper die down before the lower die has reached its position of exact aline- Inent beneath it, thereby damaging the dies or breaking some part of the press. It has Serial No. 677,654. (No model.)

which overcomes this liability and in which the sliding bed is operated automatically, but under the operators control, so that the-operator has only to remove the finished work, apply the new work in its place, and press the lever or treadle which efiects the startingv of the press.

Figure 1 of the accompanying drawings is a perspective view of my improved press, the dies being omitted. Fig. 2 is a side elevation of the press in the position of rest. Fig. 3 is a front elevation thereof. Fig. 4 is a side elevation, partly in section, showing the press inthe active position with the dies brought together. Fig. 5 is a diagrammatic elevation on a smaller scale, showing the preferred method of belting. Figs. 6 to 9 are fragmentary views showing the clutch mechanism, which, however, forms no part of my invention, Fig. 6 being an elevation looking in the same direction as Fig. 2 and partlyin section on the line 6 6 in Fig. 3, showing the parts at rest, Fig. 7 being a similar elevation showing the position of *the parts just after engaging the clutch, Fig. 8 being a vertical midsection showing the position at the instant of clutch engagement, and Fig. 9 being an under side view looking inthe direction of arrow 9 in Fig. 8, partly in section on the line 9 9 therein, and showing the position of the clutch when disengaged.

I will proceed to describe the preferred embodiment of my invention with reference to the accompanying drawings.

Let A designate the main frame of the press, which is constructed or shaped in any usual manner to provide bearings and supports for the working parts. At the upper part of this frame is mounted the operating-shaft B,which works the usual sliding head 0, carrying the upper die, of which I have shown one example, (lettered a,) whilethe lowerdie b is car= ried by a sliding bed or table D. The head 0 slides in vertical ways 0 c and is connected by an adjustable pitman d to a crank e (or eccentric) on the shaft 13. Any known means, however, of operating the head'O from the shaft B may be used, this means forming no part of my invention. The sliding bed or table D moves in horizontal ways f, on which it is movable from the position shown in Fig.

2, where the lower die I) is entirely clear of the upper die to facilitate the removal of the finished work and the placing of the next piece to be operated on, to the position shown in Fig. 4, where the lower die is in alinement with the upper die.

The die-operating shaftB is driven, as usual in such presses, from a continuously-revolving pulley E through the medium of a onerevolution clutch F, so that whenever this clutch is engaged the shaft executes one revolution, moving the upper die from its uppermost position of rest down to its lowermost position and then returning it to its upper position, whereupon the shaft stops and remains stationary until the clutch is again engaged. Numerous clutches of this character are known in the art, any of which may be used in connection with my present invention, and I do not limit myself tothe use of any particular clutch; but to facilitate an understanding of the essential operation of the machine I have shown in Figs. 6 to 9 one suitable form of clutch, this being known in the art as the Johnson clutch. Referring to these figures, the shaft B is concentrically reduced at g, on which reduced portion the pulley E turns freely, while adjacent to this reduced portion there is fixed on the shaft a collar h, within which the shaft is formed on one side with a keyway in which and in a coinciding recess in the collar h freely works a bolt 1', pressed toward the pulley by a spring j within it, which reacts through a plunger 10 against the end of the keyway. An operating-lever G, pivoted at l to the frame, has its free end beveled at m, this beveled end normally engaging a notch i in the bolt 2', as in Fig. 6, holding the bolt pressed back, as shown in Fig. 9, so that as the pulley E revolves its notches n, of which there are preferably three, pass the end of the bolt without engaging it. lVhen, however, the lever G is pulled down, as in Fig. 7, the bolt 1) is pressed by its spring j against the pulley-hub, and when the first notch n reaches coincidence with it its spring presses it into this notch, and thereby locks the shaft to the pulley during one revolution, at the end of which lever G, meanwhile having been restored to its uppermost position, reengages the bolt 2' by its inclined portion on entering the notch vi in the bolt and acting as a wedge to draw it back. Usually such a clutch is operated by a rod extending from the lever G down to a treadle or hand lever. In applying such a clutch in connection with my invention I connect its operating-rod p to an elbow lever or tappet q, (having a spring q for normally pressing up the rod 1),) the lower arm of said lever standing in the path of a tappet-screw 0', carried by the sliding bed D, so that when the bed is advanced to the operative position its screw r toward the end of its movement strikes the lever q and displaces it, thereby pulling down the rod p, as shown (to an exaggerated extent) in Fig. 4, and as this rod 12 is connected to the operating-lever G the clutch is engaged in the manner described, and the shaft B executes one revolution, causing the upper die a to descend against the lower die and reascend. To insure the stoppage of the shaft after this one revolution, since the tappet-lever q still remains displaced, it is necessary to introduce a trip device for releasing the clutch, which may be variously constructed; but the construction shown in Figs. 6 to 8 is suitable. Here the rod 19 is fixed at its upper end in a block 3, in which slides a supplemental rod p, the upper end of which is pivoted to the lever G, and which is pressed upward by a spring 8' reacting against the block 8 and acting against a collar 5 so as to press this collar up into firm engagement with a nose or hook t on a dog H, pivoted in a slot in the block 8, Fig. 8, and pressed up by a spring or springs t. \Vhen the rodp is pulled down, it carries'the block 8 and dog H with it, and consequently also the rod 1) and lever G, pulling the latter down to the position shown in Fig. 7 and engaging the clutch. In the resulting revolution of the shaft B a cam h on the collar It strikes the upper end 25 of the dog H and throws it off to the position shown in dotted lines in Fig. 7, thereby disengaging its nose 23 from the collar 8 and releasing the rod 13, which instantly is pressed up by its spring 8, thereby restoring lever G to its normal po sition, so that upon the end of the revolution of the shaft this lever acts to disengage the clutch. Various trip devices for this purpose are known, and any such device may be substituted for that shown, all that is essential being that the clutch shall be caused to free itself at the end of one revolution, so that a second revolution of the shaft cannot occur, notwithstanding that the clutch-operating detents r q are still engaged.

So far as described the sliding bed D might be operated by hand, in which case my invention would secure the advantage of guarding against premature engagement of the clutch F, such as is liable to occur when the ICC IIC

engagement of this clutch depends upon the pressing of a treadle by the operator after he has slid the bed into the active position, since it will occasionally happen that the operator will, through an inadvertent movement, actuate the treadle before the bed is brought into exactly the correct position to insure coincidence of the dies; but according to my com-- plete invention I provide means for automatically operating the bed, as will now be described.

Behind the frame Am in any other convenient location is arranged a bed-operating shaft J, which by preference is normally stationaryand is driven one revolution at atime whenever required by means of a continuously-revolving pulley K, turning freely upon it, and to which it is coupled at intervals by a one-revolution clutch L. The pulleyKrevolves at a considerably slower rate than the pulley E, and with the mechanism shown their speeds are preferably in the ratio of 1 to 3.4; but the exact ratio is unessential. The clutch L may be of the same construction as the clutch F, already described, and may or may not have the throw-ofi device consisting of the dog H, auxiliary rod 13, cam h, &c., as described. I have shown it as without any such throw-off device,the clutchoperating lever G in Fig. f being connected by a single rod 29 to a treadle-lever T, by depressing which the press is started and by releasing which before the end of one revolution of the shaft J the press stops at the end of that revolution. The shaft J is connected through anysuitable mechanism with the bed D in such manner that during one revolution of the shaft the bed shall be moved from the position shown in Fig. 2 to that shown in Fig. 4, shall there dwell long enough for the upper die to come down into engagement with the lower die and to reascend clear of the latter, and shall thereupon execute its return mo tion to the position shown in Fig. 2. Obviously this result could be attained byacam mechanism; but I have devised a better means for this purpose, which I will describe in detail.

The shaft J is formed withacrank J,which engages a link or connecting-rod M, the opposite end of which is jointed at w to a swinging arm N, pivoted at u, to the frame, so that the axis of their joint swings in an are, as shown by dotted lines in Fig. 4. The arm N is solely for the purpose of guiding the forward end of the rod M and confining it to a path which may be a slight circular are, as shown, or it might,to equal effect, he astraight line. The joint 1;, which may be made by means of an ordinary pivot-pin, connects also to a link (or preferablya pair of links) P, the latter being in turn jointed by means of a pivot-pin w or otherwise to ashort lever-arm Q, which is fixed on a rock-shaft R or is otherwise pivoted or fulcrumed, while on this same shaft is fixed a long lever-arm Q, the

free end of which, being preferably forked, is connected through the medium of a link S with a lug or pair'of lugs 00, formed on the underside of the sliding bed D. In the starting position shown in Fig. 2 the axis of the link P maymore or less approximate parallellism with the path of movement of the pivotal end t of the rod M and stands, preferably, at approximately right angles to the crank Q. As the movement of the crank J pulls the rod M backward a thrust is exerted through the link P against the lever-arm Q until the position shown in Fig. 4 is reached, at which time the axis of the link P stands approximately at right angles to the path of movement of the pivot 4;. Obviously at the instant when the axis of P stands exactly at right angles to said path the arm Q com es to rest. The parts are so proportioned, however, that this occurs shortly before the end of the movement of M, so that the final movement carries the link P slightly beyond the right-angle position, as indicated in Fig. 4. The movement during the near approach to the right-angle position is very slow, and, in fact, almost imperceptible, and the same is true of the movement slightly beyond this position to the extreme point shown in Fig. 4, and likewise of the first portion of the return movement of M, during which the link P rocks to and beyond the right-angle position until a point is reached where the link begins to participate materially in the movement of M, with the result that during these portions of the movement, amounting to approximately twenty-five degrees of the movement of the shaft J preceding and succeeding the position shown in Fig. 4, the lever Q Qis practically at rest, thereby imparting the requisite dwell to the bed D to afford time for the upper die a to descend into engagement with the lower die and to reascend clear thereof. In other words, assuming that the pivotal end i; of the rod M is guided by the swinging arm N, as shown, this arm and the link P constitute together-a pair of toggles, which in the initial position shown in Fig. 2 are doubled up and are straightened by the pull of the rod M until they are in alinement and pass slightly beyond alinement, as shown in Fig. 4, so that when near the position of alinement but little motion is communicated by the toggles to the lever Q Q. The result stated is of course greatly contributed to by the diminishing movement applied to the rod M by the crank J as the latter approaches its dead-center and recedes therefrom. It thus results from the combination of crank and what is approximately if not essentiallya toggle movement that the bed D is rendered substantially immovable duringa period or dwell of approximately fifty degrees, or during sufficient time to permit the upper die to act upon the lower one. In fact, however, this condition is not one of absolute immovability, but a very close approach thereto, and to compensate for the slight movement that is engendered I introduce at some part of the mechanism a spring or cushion g, which preferably forms part of the link S, which thus is made a yielding or compressible link, although the spring might be elsewhere introduced to like effect. Thus the bed D is pushed forward through the medium of a yielding spring or cushion until the bed is stopped with the dies in exact alinement by striking an adjustable abutment consisting of screw-stops z, (one or more,)'

whereupon the slight additional movement imparted to the lever Q Q is taken up in compression of the spring y. In the construction shown the link S is made with an opening or chamber in which the springyis housed, the spring being seated at one end against an adjusting-screw a, by which to regulate its tension, and at the other end against the end of a sliding member b of the link, consisting of a neck sliding through a hole in the main link member and formed with an eye which engages the pivot-pin con necting it with the lugs ICC IIO

IIS

a: on the bed. The pivotal end 1; could be guided by means of a block 1), sliding between ways 1- as indicated in Fig; 5; but the construction first described is preferable.

The pulley K may be driven, as shown in Fig. 1, by belting from a pulley E, fixed to the pulley E and of smaller diameter to give the desired ratio of slower travel to the bedoperating shaft J. I prefer, however, to drive both pulleys E and K from pulleys E and K respectively, on a counter-shaft, according to the arrangement shown in the diagram Fig. 5.

In Fig. l is shown the usual friction-brake U, applied to the operating-shaft B, which brake is omitted from the remaining figures for greater clearness.

The provision of a one-revolution clutch L for controlling the bed-operating shaft J is preferable, but is not essential to my invention, as this shaft might be driven continuously for certain kinds of work or might be driven through the medium of other clutches or belt-controlling means than those of the one-revolution type.

My invention may be modified in certain particulars without departing from its essential features. For example, the clutch F may be actuated otherwise than through the medium of the bed. D, acting through tappets. Thus any partof the mechanism which moves when the bed moves may be utilized for setting in motion at the proper time the clutch which drives the shaft 13.

The link P is essentially a toggle-link, whether the upper link N (constituting with it a pair of toggle-links) is used or not, since this upper link may be substituted by other means for guiding the pivotal end o of the link P, such as by the provision of guideways, as described with reference to Fig. 5, which constitute an equivalent for the upper or guiding link.

I claim as my invention the following-defined novel features, substantially as hereinbefore specified, namely:

1. The combination of the sliding head for carrying the upper die, its operating-shaft, a one-revolution clutch for driving said shaft, the sliding bed for carrying the lower die, a bed-operating shaft and connections for sliding said bed beneath the head and back, and means for engaging said clutch at or near the end of the advancing movement of said bed, adapted to cause the shaft to revolve so as to bring the dies together after the slide has advanced into its operative position and to separate them before the slide commences its return stroke.

2. The combination of the sliding head for carrying the upper die, its operating-shaft, a one-revolution clutch for driving said shaft, the sliding bed for carrying the lower die, a bed-operating shaft and connections for sliding said bed beneath the head, causingit there to dwell, and then returning it, and means for engaging said clutch timed to cause the shaft to revolve and bring the dies into and out of engagement during said dwell of the bed.

3. The combination of the sliding head for carrying the upper die, its operating-shaft, a one-revolution clutch for driving said shaft, the sliding bed for carrying the lower die, a bed-operatin g shaft and connections for sliding said bed beneath the head, causing it there to dwell, and then returning it, said shafts having driving means for turning them at differential speeds, that of the former being materially faster than the latter, and means for engaging the clutch of the former and faster shaft at or near the end of the advancing movement of the bed, timed to cause the revolution of the shaft to bring the dies into and out of engagement during said dwell of the bed.

4:. The combination of the sliding bed for carrying the lower die, the sliding head for carrying the upper die, the operating-shaft for said head, a one-revolution clutch for driving said shaft, and means for engaging said clutch operated by the advancing movement of the bed and adapted to cause the shaft to bring the dies together after the slide has advanced into its operative position.

5. The combination of the sliding bed for carrying the lower die, the sliding head for carrying the upper die, the operating-shaft for said head, a one-revolution clutch for driving said shaft, and means for engaging said clutch comprising an adjustable tappet carried by the bed, and a device arranged to be displaced thereby toward the end of the advancing movement of the bed and connecting to said clutch to engage the latter.

6. The combination of the sliding bed for carrying the lower die, the sliding head for carrying the upper die, the operating-shaft for said head, a one-revolution clutch for driving said shaft, means for engaging said clutch operated by the advancing movement of the bed and adapted to cause the shaft to bring the dies together after the slide has advanced into its operative position, and means for insuring the disengagement of the clutch at the-end of one revolution.

7. The combination with the sliding head for carrying the upper die, and means for operating it, of the sliding bed for carrying the lower die, a bed-operating shaft and connections for sliding said bed beneath the head and back, said connections comprising a toggle-link operated by said shaft, and a lever moved thereby and communicating its movement to the bed, said link arranged to approximate at one end of its movement a position at right angles to the path of the thrust imparted to it from said shaft, whereby to diminish the movement imparted to the lever and impart a dwell to the bed when the latter reaches the operative position of the dies.

8. The combination with the sliding head for carrying the upper die, and means for operating it, of the sliding bed for carrying the lower die, a bed-operating shaft and connections for sliding said bed beneath the head and back, said connections comprising a toggle-link one end of which is restrained to movement in a definite path, a crank on said shaft and connecting means for communicating its thrust to said end of said link, alever to which the opposite end of the link is connected, said link arranged to approximate at one end of its movement a position at right angles to the path of the thrust imparted to it from said shaft, coincidently with a dead-center position of said crank, whereby together to diminish the movement imparted to the lever and impart a dwell to the bed when the latter reaches the operative position of the dies.

9. The. combination of the sliding head for carrying the upper die, its operating-shaft, the sliding bed for carrying the lower die, a bed-operating shaft, and mechanical connections between said latter shaft and the bed for sliding the latter into operative position with its die beneath the upper die, and for returning it, said connections comprising a pair of toggles, actuated by said shaft and communicating movement to the bed, arranged to straighten coincidently with the operative position of the dies, to impart a dwell to the bed.

10. The combination of the sliding head for carrying the upper die, its operating-shaft, the sliding bed for carrying the lower die, a bed-operating shaft, and mechanical connections between said latter shaft and the bed for sliding the latter into operative position with its die beneath the upper die, causing it there to dwell while the dies come together and separate, and for then returning it, a stop for the bed in said operative position, and a cushioning-spring interposed in the bed-driving connections adapted to yield and take up superfluous motion during the dwell of the bed.

11. The combination of the sliding head for carrying the upper die, its operating-shaft, the sliding bed for carrying the lower die, a bed-operating shaft, and mechanical connections between said latter shaft and the bed for operating the latter, comprising a togglelink P having its end 1; confined to a definite path and operated from said shaft, a leverarm Q to which the opposite end of said link. is pivoted, a lever-arm Q fixed to the arm Q, and a link connecting the arm Q to the bed.

12. The combination of the sliding head for carrying the upper die, its operating-shaft, the sliding bed for carrying the lower die, a bed-operating shaft, and mechanical connections between said latter shaft and the bed for operating the latter, said connections comprising a lever-arm Q, and compressible link S connecting said arm to the bed, said link formed with two relatively sliding members, one pivoted to said lever-arm and the other pivoted to the bed, and with a cushion-spring y between them adapted to yield and take up superfluous motion during the dwell of the bed.

13. In a press, the combination with the slid ing bed D and its operating-shaft J and intermediate connections, of a compressible link S forming part of said connections and comprising two relatively sliding members, with a cushion-sprin g y between them adapted to yield and take up superfluous motion during the dwell of the bed,-and an adjustingscrew a for varying the tension of said spring.

let. In a press, the combination with the sliding bed D and its operating-shaft J, of means for communicating motion from said shaft to the bed consisting of a crank J on said shaft, a pair of toggle-links N P, a connecting-rod M from said crank to the joint of said links, a lever arm Q receiving the thrust of said toggle links, a rock-shaft R on which said arm is fixed, a lever-arm Q fixed on said shaft, and a link connection between said latter arm and the bed, arranged to straighten said to gle coincidently with the operative position of the dies to impart a dwell to the bed.

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

FRANK M. LEAVITT.

Witnesses:

FRED WHITE, THOMAS F. WALLACE.

Images