US1369853A - Griving of tool machines - Google Patents

Description

A. TETTLENI. llllVlN QF 'WOL MACHINES, ESPECIALLY FOR VARIABLE WORKING RESISTANCE.

APPLICATION FILED NOV. 26, l9l` 1369853 Patented Mar. 1, 1921.

9 SHEETS-SHEET l wf/Won! 'mmf A. TETTLENI. DRIVING 0F TOOL MACHINES, ESPECIALLY FOR VARIABLFn WORKING RESISTANCE.

APPLICATION FILED NOV. 26| '|9171 .w M W ,w d ...W9 c. n m im. d

A.: TETTLENI. DRIVING 0F T001 MAcmNEs,EsPEc|ALLY FoR VARIABLE woRKlNG RESISTANCE..

APPLICATION FILED NOV. 26, 1917.

1,369,858. Patented MA1. 1, 1921.

I 9 SHEETS-SHEET 3.

SMA d A. TETTLLNH. DRIVING 0E TooL MACHINES, ESPECIALLY EoII VARIABLE WORKING RESISTANCE.

APPLICATION FILED NGV. 26, |917.

L69, 85. PAI-Anm Mar. 1, 1921,

9 SHEETS-SHEET 4.

A. TETTLENI.

DRIVING 0F TOOL MACIHINESJSPECIALLY FOR VARIABLE WORKING RESISTANCE.

APPLICATION FILED NOV. 26| I9I7.

Patented Mm'. 1, 1921.

s suiesnezr 5 l/V VEN T05:

A. TETTLENI. DRIVING 0F TOOL MACHINES, ESPECIALLY F-OR VARIABLE WORKING RESISTANCE.

. APPLICATION FILED NOV. 26, 1917. 1,369,853.

Patented Mar. 41, 1921.

9 SHEETS-SHEET 6.

A. TETTLENL y DRIVING 0F TOOL MACHINES.ESPECIALLY FOR VARIABLE WORKING RESISTANCE.

APPLICATION FILED NOV. 26 19|?.

Patlld Mill'. 1, 1921.

9 SHEETS-SHEET 1.

- A. TETETLENI. DRn/.ING of TlovoLl M'AcHxNEaEsPEClALEY FOR VARIABLE woRKmG RESISTANCE. l v APPLICATION FILED NOV.26. 1917. 1.33639,853; Patented Mar, 1, 1921.

9 SHEETS-SHEET 8.

@NUL/OM. JW(

A. IETTLENI.

DRIVING OF TOOL MACHINES. ESPECIALLY FOR VARIABLE WORKING RESISTANCE.

APPLICATION FILED NOV. 26.1917. I

` .Pa-hemd Vm. L V921.

9 SHEETS-SHEET 9- MORRIS PEYERS, INC Limo WAsrIlNGoN4 D C NETI ` ARMIN TETTLEN, Oli' BUDAPEST, HUNGARY.

DRIVNG- 0F TOOL-lllAC-NES, FR VrliItIABLl-E WORKING RESISTANCE.

rasante.

To all fw 710m it may concer/n Be it known that l, Antritt lnrii'rnnni, a subject of the ylling of Hungary, residing at Budapest, l-lungarj, have invented new and useful lmprovement in the Driving of Tool-Machines, Especially for Variable lVorking Resistance, of which the following is a specification. y

Most of the sual machine tools driven, c. g., by eccentrics,'levers and the like, With reciprocating tool (plate shears or cutters, punching machines, presses, etc), which perform Work on blanks with variable Working resistances, have the defect that they do not take into account in different cases the actual amount of resistance Work of the blank or 'the continuously varying values of the same in the different phases of the Working stroke, but are designed rather on the basis of the maximum strain for the entire Working stroke, and they must therefore be given a Working capacity which is too high4 in proportion to the total Working resistance which must actually be overcome. rlfhis results in machine parts of more than necessary strength and hence in high cost of construction. Moreover, the Waste of pov/er, in which the excess means nothing more than an unnecessarily high and harmful acceleration of the mass, renders the operation far too expensive.

lt is true that drives haveJ heretofore been devised Which slioiv a certain tendency to take the varying Working resistances in one direction or the other into account for the transmission of movement. But these drives are, on the one hand, relatively complicated, While, on the other hand, they can by no means be said to represent a systematic adaptation-21 c., an intelligent adaptation to cach phase of Work, allowing in every direction for the requirements in each individual cases-to the continuously varying unequal distribution of the vfactors (power and stroke) or the Work actually ra quired for the entire Working stroke. Still less can they be said to represent a prodetermined intervention in the ratios ofthe Working factors at any given periods of stroke or time in the process of Work tothe end of influencing the same at Will in the most varied cases.

.Thus, for instance, drives for riveting machines and the like have become known in which the ratio of transmission of the driving shaft to the tool holder shows its Specification of Letters Patent.

nnurirnuin value at the end of the Working stroke, and in which the speed and driving power vary in inverse ratios The latter, however, has been the case only in a very general sense i. e., Without any possibility of taking into account the so-called diagram of Work at given points of the process of Work. Still less has ity been possible to exercisc an intervention, such as mentioned above, in any, given phase of the Work and in any desired manner.

rlhese machines, ltherefore, (with the single exception of theknown adjustability of the Working stroke by radial displacement of the driving pin) lack the possibility of allowing in one and the same machine for the greatly varying cases of Working, such as result from the different kinds of blanks ha'. e., the nature of the material, dimensions, etc. hence the different behavior of the same under the tool, accordingto which it becomes necessary to reckon with entirely different conditions of accumulation (or upsettings) of the material, etc., and hence with entirely different values of the Working resistance in each case. In special cases it is also necessary to exert an influence, corresponding exactly to practical requirements, upon the course of the Working factors With regard to any given point between the beginning and the end of the stroke.

According to the invention a drive is created Which is capable of meeting perfectlyl and in every Way the practical requirements in all the above mentioned respects. The essential features of the invention, or the considerations upon which it is based, Will first be explained With the aid of the accompanying drawings, in vvliichn Patented Mar. i., 1%21.

Application led November 26, 1917. Serial No. 20Li,132.

l*1 igurc l is a diagram representing the l resistance of the Work piece considered as a function of the time.

lig. 2 is a diagram representing the resistance of the 'Work piece considered as a function of the Work stroke.

Fig. 3 shows anembodiment of the nvention, as applied to a shears.

Fig. l is a diagram illustrating one method of determining the form of a groove in the tool holder adapted to coperate with a driving element carried by a rotating driver, in accordance with the principle of the invention herein disclosed.

Fig. la is an auxiliary'ligure, to be considered in connection with Fig. 4.

Fig. 5 isa diagram illustrating a method of determining a groove or slot of a somewhat dierent form, a portion of which controls the return stroke of the tool holder,

,as well as a part of the work stroke, the

to'thatl of F ig. 5, but adapted to increase thel ratio of driver movement for the working stroke, with respect to that for the return stroke.

.l3`ig.`V illustrates a modiiication of the invention, as applied to ashears, in which a secondary swinging driver or transmission element is introduced between Vthe primary rotatingdriver and the tool holder.

Figs`8 `and 9 arel diagrams illustrating methods of determining the forms of grooves orslots to cooperate with driving elements, in accordance with the princi )le of the invention, when applied to a mec ia` nism of the form shown in Fig. 7.

Fig. l0 illustrates the variation in the Veffect produced upon a tool holder by a variation in the form of slot which coperates with the driving element on the secondary transmission element.

Figs. 1l and 12 are details, illustrating a practical means of substituting a slot of one form foro-ne of a different form.

Fig. 13 shows an embodiment of the invention, in which a plurality of tool holders of a universal machine may be driven by a common, swinging transmission element, which is itself driven by the rotary driver.

ln Fig.V l the curve P represents the resisting power of the blank as a function of the ltime't 'of the workin@ stroke, while in Fig. 2 the curve P represents said power asa function of the length of the working stroke Z, the lines of the timevand length of stroke being expediently drawn in the ac tual direction of the latter, namely, vertically. In the example chosen the work to be performed is separation of material (punching, perforating, cutting or shearing), and the diagrams, known or obtainable by experiments, are partly drawn on an exaggerated scale for thev sake of clear ness. ln many cases, especially for the perforation of metals, the course of the curve P', for instance, is such that it iirst rises slowly, then very rapidly owing to the accumulation of the material, reaching its maximum about at the point 7 of the length of the stroke, corresponding to half the time (or duration) of the stroke, then sinking again very rapidly, at iirst much more rapidly than it had risen before reaching the maximum, but then, in the vicinity of the line l, descending in a very flat longstretched curve to the O-value at the end of the stroke. ln these cases therefore the shape of the curve comes to be perfectly asymmetric. For graphic considerations (i. e., in order to render the below described method of construction of the transmitting mechanism of the invention more comprehensive), we will take for an example the symmetric form of the diagram of forces of the working resistance, which is the simple theoretic form, but in many cases also essentially the correct practical form. This is however immaterial as far as the invention is concerned, since the latter, as will bc seen from the following explanations, is applicable in the same manner to cases oi any given resistance curves.

lt is obvious that in Fig. 2

13 f raz,

i. e., the area O-Pmx-a, represents the diagram area of the greatly variable working resistance, 2'. e., the work to be overcome by the tool in the course of a working stroke. A reciprocating movement is imparted to the tool holder in a known manner by a driving device rotating at uniform peripheral speed and power, or in certain eases oscillating (eccentric pin of a driving wheel, crank pin, eccentric, rocking hand-lever, etc.,) by means of one or more suitable transmission devices. In order to render the useful work perfectly economic in accordance with the purpose of the invention, we must First take as a. standard for the uniform work of the driving device for that part of its rotation or oscillation (working or forward stroke) which corresponds to the working stroke, the area of the diagram of work compensated in a rectangular quadrangle by the dot-and-dash line 6 (in the manner indicated by hatching),

13 f PdZ=eZ or es respectively, in order to impart t0 the driving device, when the length of the curve of its forward stroke is s, for instance, the circumferential power X to be determined from the equation e.Z:X.s. The area cZ shows the great economy over former machines in which the driving work was equal lio Plmaxa.

all cases. Let the time ot the stroke t (Fie. l) or the length ot the curve of the'iforvvard stroke of the driving device be subdivided c. g., into 13 equal parts At. F or each part At the same 13th part of the area el (Fig. 2) is available tor the Work. Consequently the diagram area 13 f Pdl (Fign) is to be divided into 13 equal parts, vvhile the parts iii/1,' iii/2 .ai/1,

'of the line Z of the stroke, as distinguished Where ai designates the number or parts it of the time of stroke. ample 93:13.

rlhis unequal division ot the stroke Z may be determined in the manner indicated in Fig. l: Afit each point l, 2, 3, etc., a given constant, e. g. io (proportional to the above ln the foregoing exe mentioned constant 7c) is divided by the corresponding power Plf, Pp, PW, Rp, etc., the result being the ordinates All AZ, etc. rlhe curve AZ (Fig. l) therefore shows the course ot the dierent parts ot the stroke required. lnstead ot' determining` the values sought at the end l, 2, 3, etc., of each section At, they may also be determined in the middle or the same taking the mean forces into account. These are then transferred in Fig. 2 in the respective ratio upon the line Z.

rlhe tool must therefore exert during the equalparts of time of the 'forward stroke of the driving device successively the respective l'orces Py, Py, etc. according to Fig. 2, which accord with the forces P1, P2, P3, etc., at the points l, 2, 3 of Fig. l, describing the corresponding partial strokes 1l-Ww Alzf, cto.

lt is in accordance with this requirement that those parts are formed and dienensioned, according to this invention, which serve `to transmit the Work ot the driving device to the tool holder.V ln the practical construction, the trictional losses etc., t. c., the mechanical efficiency or' the gearing, must of course be taken into account,

For the purpose or' the variable transmission in question any positive paths and types of gears, not neviT in themselves, (e. 9 elliptical toothed gears, etc.,) may be used. According to one form ot construction o'l the invention, however, oscillating crank gear, for instance, or in some cases rotating crank gear may be employed which is simple and expedient; but, as distinguished from known constructions, the link slot or the groove of the respective loop does not have the shape ot a straight line but that ot a curve which corresponds to the variable transmission determined in the manner stated on the basis ot the diagram of Work ot the resistance et the blank or correspond ing to some additional intervention Which may be desired.

lily employing a suitably shaped curved slot or the like, it becomes entirely possible to insure or subsequently alloiv l'or any ratios that may be temporarily required in a machine tool. For in order to meet the requirements with one and the saine machine at all times, even when the conditions of Aivork vary considerably (blanks of different materials and difrereiit dimensions), the

curved slot or curved groove, etc., is turthermore preferably formed, according to the invention, in an exchangeable part ot' the oscillating lever Which transmits the Work thereby rendering it possible, provided a supply of such different parts is kept on hand, to meet the most varied Vconditions Without taking the machine apart-z'. c., to render one and the same machine serviceable for a long series oit apparatus ci the most varied types, which would otherwise have to be represented by as many diilerent machines.

ln addition to the foregoing, the invention admits oi an arrangement whereby the above mentioned transmission member, hereinatter alled the primary member, connected with the driving device, is enabled to act upon the tool not only directly but also by means of one or more additional transmission members secondary, tertiary, etc,) of the same or ot a dierent kind. Through such an additional member it becomes possible to influence or supplement at will according to requirements the action of the primary member tor any part et the tor- Ward or return stroke, thereby meeting the most varied practical conditions in special cases.

lt is obvious that owing to the employment oi' a secondary, etc., member in combination ivith the `above mentioned exchangeability oit the curved slot (applicable according to circumstances to the primary or the secondary member or to both) a practically unlimited number oi' special cases of Working with one and the same machine may be considered.

rlllie invention also atlords the possibility of realizing another moment in a much more favorable measure than heretofore, especially in the case of machine tools tor talring ott chips (or cuttings), namely the tendlOO ency, not new in itself, to shorten the return stroke. The usual ratio between the work- Ving stroke and the return stroke is about 7 4 ments of construction in the meaning or the -inventiom a much more iavorable ratio between the return stroke and the working stroke is attainable, so much so that the relative amounts of the respective values oi' the forward and return strokes are limited only by the feasibility of practical execution, but by no means by yfundamental dithculties.

The invention, which embodies further advantages hereinafter described, is illustrated diagrammatically in Figs. 3 to 13 of the accompanying drawings, showing a few examples of construction.

YAccording to Fig. 3, which shows a general arrangement of the simplest embodiment of the invention, applicable, e. g., to a cutter (or shears), a slot 4 is formed in the rocking lever 2 carrying the movable shear blade l, which lever is rotatable about the shaft 6 mounted in a frame 3 which receives the fixed shear blade. In said slot 4 engages the eccentric pin 5 of the driving wheel 7 or similar device (crank, rocking lever, ctc.,) mounted at 8. The curve ot' slot 4 is constructed on the basis of the diagram of work in a manner to be hereinafter described. The positions 4 and 4 of the slot, drawn in dotted lines, correspond respectively to the position of the same at the 1 end of halt a rotation of the driving pin 5 and at the end of the working stroke. The short part of the arc between the points R and 0 corresponds to the duration of the return stroke.

As regards the mode proper of construction of the curved slot, curved groove, etc., on thev basis of the above mentioned diagram oli' work, two methods in particular present themselves. ln order to determine the diiierent points of the curve, either the dilierent forces PQ, IN2, etc., (Fig. 2) or the partial strokes XZ/1, AF2, etc., may be considered. Let us assume, 'to-r insta-nce, according to Fig. 4, which shows the method of construction or" the geometric middle line of the link on a `larger scale, that in the driving circle (or travel circle) M (circular path of the eccentric driving pin rotating at a constant speed), the greater part of which is subdivided into a number of, e. g., 18, equal parts, the part 0-13 ot' the arc corresponds to the forward stroke and the part 1.3--0 to the return stroke. According to the rst mentioned method it is necessary to determine for each point l, 2, 3 13 oi the travel circle the corresponding` point ot the curve which at the moment when the link is in engagement with the driving pin at that point produces in the tool l, in accordance with the ratio of transmission, the corresponding power Pl, Pg, etc., onthe basis oit the diagram of work. The mean arc of oscillation ot said tool is designated by B (Figs. Il and 4), while the angle oi deflection ol the lever carrying the tool (not shown) and rotatable about the axis A is designated by U.. On the circle B is seen the part of the arc (l-l which corresponds to the stroke und which on the basis of the diagram of work is subdivided into the required number ol: unequal parts corresponding to the diiliercut values AZ.

The dili'erent parts of the slot curvo would then have to be determined in the iollowing manner:

In Fig. 4, let the point 3 be some point on the travel circle M (Fig. 4) the radius of which is designated by r. fr, is the line which connects the point 3 with the axis ot oscillation A (Fig. 4)-21 e., the radius of oscillation oi the part 7c, corresponding to said point 3, ot the curve sought. The force P., (Fig. corresponding to the point 3 must act in the direction of the tangent of the circle l (Fig. 4). Accordingly let said torce be laid down as PQ, at the point 3 ot Fig. 4fl perpendicularly to the line r1 ou a correspondingly reduced scalec1 e., reduced in the ratio of the radius of the circle B and of the length of the line 11,. U is the circun'iferential force of the dri fing pin known by reason of the balanced diagram of work.

To the principle of the positive movements or of the known conditions ot static and dynamic forces oiE the same correspoml in the present case the parallelograms ot forces shown in Fig. 4, while for the positive path f: may be substituted the normal N, i. c., the force vertical on the path. The force available-ei. c., the circumferential force U--is subdivided in a known manner into the normals of the two paths to he considered, the positive path ,7c and the travel circle. These normals are: the force N just mentioned and the force Z1, which latter, as momentary static torce, represents the journal pressure in the axis C of the travel circle. The torce N is subdivided into the forces 1)3 and Z2, which latter, as momentary static torce, represents the journal pressure in the axis of oscillation. The work of the moving force U is equal to that oi' the force PWS, especially since other moving forces are not acting. Of the above mentionedV quantities of the parallelogram of forces only 1)3, or the corresponding force at other points, and U are known. At each point the direction of the normal N, or, which is equivalent, the angle of inclination of the tangent T of the curve in to the direction of the circumferential force U, must be determined in such a manner that at the respective point, according to the parallelogram of forces, the required driving power will result as component (in the example chosen, P3). The slot curve begins at the point 0 of the travel circle M, and the different parts is of the curve, determined in accordance with Fig. 4, or the tangente T surrounding them at said point 0 or connected to one another, must of course be laid out by bringing the arc back through the distances corresponding to the paths of oscillation traveled by the tool holder to the respective points of the travel circle, in order to obtain the connected curve to be constructed.

The above described method however appears somewhat lengthy. It is therefore preferable to use the other method of construction based on the partial strokes AZ1, AZZ, etc. The result is the same in the two cases, since, owing to the constant product representing the work available at the driving pin, the determination based on the different forces corresponding to the transmissions must of itself show the required parts of the stroke and vice versa.

For the mode of construction of the curve on the basis of the partial strokes two methods present themselves, an analytical-dynamic one and a geometric one. The latter is simpler, but the former is more comprehensive in connection with Fig. 4, in which different positions and the below described angles are shown, and for that reason the former method of construction will be described first.

The different points of the curve K to be constructed (Fig. 4) all swing about the axis A. The point at which the driving pin comes into contact with the slot, curve for the beginning of the movement at the point 1 of the travel circle must therefore lie on the arc al, and in the initial position of the curve at such a distance from the lpoint 1 of the travel circle that as soon as the loop reaches that point-Ji. e., intersects the circle M at said point-the tool holder will j ust have completed the irst part of its stroke. Accordingly the point 1 of the circle M is connected with A, and at the point of intersection S of said connecting line 1-A with the arc B, the distance d1 is laid out on the right, to which corresponds on the scaleof the diagram of the work partial stroke All, whereupon the right-hand end point S of the distance d, is connected with A. In accordance with the ratio of transmission between al and B, the point of intersection of the line SL-A with the arc al will then furnish the lirst point sought 1 of the curve K. The same applies to the remaining points, but in order to keep the curve in the initial position the distance already traveled in each case must be taken into account, which is done in the following manner:

.F or the point sought 2', or the part 1--2 of the curve respectively, the movement on the part 1 2 of the travel circle is taken into account. For the construction of the initial position of the curve the part 1-2 of M must therefore be carried back on the circles of oscillation a, and a2 respectively until the lower end point of the same comes to lie at Z. For the purpose of thus carrying back the circle M relatively to K, the circle of oscillation drawn from the axis of oscillation A with the radius AC is intersected from the point 1 with the radius r of the travel circle, whereby the point C, is obtained, and then from the latter with the same radius the arc 1--20 is drawn. The point 20 is then connected with A and the construction continued on the basis of the partial stroke (l, in the same manner as described with regard to the point 1. After the point 2 has been determined, the points 30 and 3 are determined from the point 2 in exactly the same manner as described with regard to the points 20 and 2. The same applies to the remaining points 4', 5 13.

1n this manner the curve K is formed to the point 13, to which corresponds the point 13 of the travel circle M. As soon as the driving pin reaches the latter point, the curve coming into the position K shown on the left side of the figure, and the point 0f beginning O of the same coming to lie in the point O of the circle of oscillation a0, the return stroke begins. 1n order to create a path for the latter, the point 13 of the curve K maybe connected by any line with the point of beginning of the same. 1n the example illustrated a straight line B has simply been used, which at the beginning of the return stroke Ycomes to be in the position R.

. 1n Fig. 4 the different positions of the curve K are also indicated by small curve sections, c'. e., by those parts of the curve K with which the latter intersects the travel circle'at the respective points 1, 2 12 of the forward movement of the driving pin. The relative angles of inclination of the curve K to the travel circle in these different positions in the course of the movement are likewise shown. rllfhese angles concord with the angles between U and T, designated by at the point 3, previously described in yconnection with Fig. 42L for the mode of construction based on the distribution of forces.

These different angles, which may also be designated as working angles, show also in a characteristic manner the course of the drive according to the invention: rlhey increase and Vdecrease in inverse ratio te the forces P in accordance with the diagra (Fig. 2)-i. e., they decrease in accordance with the diagram AZ (Fig. 1) or the partial strokes AZI, AZZ, etc., `(Fig. 2), reaching),` their minimum about the middle of the working stroke, where P ismaximuin, and increase likewise in accordance with the values AZ.

It is obvious that the shape of the curve l is determined, among other things, by the choice of the point 18 of the travel circle, and that such choice may be made at will according to requirements. In other words, when the highest possible ratio is desired between the working stroke and the return stroke, it is possible to bring the point 13 as close t0 the point 0 as desired without interfering with the possibility of the abovel describedconstructi'on of the curve K. lt is merely the practical feasibility of construction, especially the necessity, existing in all cases, of providing a path, it ever so short, for the return stroke, that puts certain restrictions, though within very wide limits, upon the choice 01"' the ratios between the working stroke and the return stroke.

It is to be noted that the first part of the curve K, at which the point() has a common tangent with the travel circle M, must under no circumstances be carried below the circle of oscillation 6%.y When it is desired to impart to the tool a still higher initial velocity, it is permissible to give the curve section between 0 and 1 an additional downwardly extending projection, e. g.,rin the manner indicated in dotted lines, but such projection, as stated, must not entend below do, because the driving pin would in that case not be able to move the link and might cause breaks, especially since to represents the prescribed lowest path ot oscillation.

It is obvious that the loop KR according to Fig.' 4, which forms a line closed within itself, cannot be in the natureV oiia slot but must be in that of a groove or the like.

In Fig.- 5 is shown the mode or" construction of the curve in accordance with the simplest embodiment of the invention, which has already been briefly described in connectionwith Fig. 3. The curve K forms the Vgeometric middle line of theslot el according to Fig. Y3 and, in distinction from the curve KR of Fig. 4, does not constitute a closed path, Vbut terminates, as will be seen, at a point corresponding'to the highest point Z of theV travel circle, which the driving pin reaches attheend of halt1 a rotation, so that during the second half of the rotation the driving pinfslides back in the same path. In this case the path, not being closed, may

' hereinafter of course be either in the nature of a groove or in that of ay slot.

ln the loop according` to Figs. 3 or 5 rcspectivcly, the curve et which up to the point S, is constructed in exactly the same manner as the curve et F ig. l, we haven simple arc-shaped slot readily applicable to all cases. But the fact must be taken into consideration that, as distinguished from the very exact solution according to F 'l, certain conditions undergo a change owing to the circumstance that the driving piu slides back in the same slot or along the same slot Yall to the beginning of the return stroke. is especially the course olf the values A?. (F 2) in the part of the working stroke following the point 8 or the length oit such part, as also the beginning of the return stroke, that can no longer be made directly to correspond exactly to the second halt oi' the diagram; still less can these values be chosen at will, but are determined by tln` curve K its-clit, which is retained also for the second part of the working stroke. Thus the hoint 13 ol? the travel circle M7 corresponding to the beginning of the return stroke, comes ot itself: to be the point et contact of thecurve K (in its position K) with the travel circle. From this it follows that in certain cases the length ot the stroke does not correspond to the length desired in the respective case but is greater, 'for instance, so that from the point 12 to the point 13, c. g., oi: the traaf'el circle an idle stroke in the workiiig direction will take place. The changed distribution ot the parts S to 13 of the stroke is apparent from the circle of orcillation B of the tool holder; these parts no longer correspond accurately te the diagram of 2, nor does the point 7 any longer correspond to the middle of the stroke, so that the second part ot the diagram actually resulting, as distinguished from Fig. Q, comes to be asymmetric to the first halt.

But it may be stated that. aside from the Vtact Ythat compliance with the lirst part of the diagram is frequently suiicient for practical purposes, we have in many instances (in the ease of certain materials and classes ci work) a very asymmetric dia- ,g m. so that the method et constriwlion according to 5, which is distinguished bj: great simplicity. can in many cases be employed with perfect accuracy. lVith regard to other cases it may be stated that by the additional employment oit further methods of improvement or intervention according to this invention, which will be described (changeability oit curve, employment of a secondary slot), all the inaccuracies connected with the simple slot according to Fig. 5 can be effectively compensated. lt is true that in the combination of said slot with a secondary slot (Fig. 7) two links are required; still, in

l l) (l l. l (l many cases the employment of two simple slots will be, preferable, for technological and mechanical reasons, to the employment of a long curved groove according to Fig. et.

In order that the form of construction according to Fig. 5 may be effective, another requirement is that the curve K must lie not only above the circle a0, as in Fig. ll, but also above the common tangent t of the circles M and a0, because otherwise (for dynamic and geometric reasons vnot to be described at length) upon the return stroke it will not be the lower end point but an intermediate point of the lower part of the curve K that will return to the point 0 of the travel circle M, so that a certain lower part of the curve is left behind `on the left side of the circle a0, and thus the desired method of operation will not be attained. Y

Although, as stated above, the point 13 ot the travel circle, e'. e., the beginning of the return stroke, and hence the ratio between the working stroke and the return stroke, is determined by the curve K itselfand can therefore not be' chosen at will, as in the method of construction according to Fig. d, the invention renders it possible even in this case to secure a considerable improvement over former ratios between the working stroke and the return stroke without materially affecting the shape of the slot constructed on the basis of the diagram. This method ,is illustrated in Fig. 6 and consists in the following:

K designates a slot according to Fig. 5 in the case of a ratio between working and return stroke which is normal from the standpoint of the invention, yet exceeds former ratios. In this case the ratio in question is i. e., greater than the hitherto known maximum 3:1. When the radius of curvature of the lower part of the curve K, which at the beginning of the return stroke occupies the position K and contacts at R with the travel circle M, is shortened so that, for instance,"the curve K, will result, the contact point of the same with the travel circle will be at R,z`. e., below the point R. rlhe angle of the return stroke is then o1 on lThis result, or even a better one, can be insured according to the invention also by other means, namely, by making the distance of the center C of the travel circle from the axis of oscillation A of the tool holder shorter in the manner illustrated, z'. e., placing it, for instance, in the point C1. From this results, even for a normal curve K2, identical with the curve K, the returnstroke angle a2 a.- Even oz2 a1 can be attained. Y

lt is obvious that by the combinatory application of the two methods last above described, as illustrated by the curve K, and the angle as, a very high measure of the ratio in question can be secured; in the ei;- ample shown, 3 a2 a', a. in the practical application a ratio of, e. g., 7 l and even above can be obtained without difficulty.

As briefiy indicated above, a machine element swinging back and forth may be employed as driving device in place of a rotating eccentric pin. Such a form of construction is shown diagranimatically in Fig. 5a, which is particularly suitable for hand operation. In this apparatus a lever 7 is capable of rocking on a shaft 8 mounted in the frame and carries a pin 5. The latter engages in a slot in the lever 2 constituting the tool holder. in its forward stroke (working stroke) the hand lever 7 swings from its initial position shown through the angle o: into the position 7 indicated in dotted lines, and in its return stroke from the latter position through the same angle into the initial position. In this movement the pin 5 describes, in accordance with the samerangle, the travel arc M, which in the drawing is subdivided into 13 equal parts in a similar manner as in preceding examples. Corresponding to the different points 0, l, 2 13, the middle line of the slot in the lever 2, is constructed on a different scale but in other respects in exactly the same manner as described in detail in connection with Fig. d. lt will be seen that in this case, as distinguished from previous forms of construction, the path of movement lies within. 180, which is proper for advantageous operation of a hand lever-z'. e., the length of the travel, path or of the slot respectively is still shorter, other conditions being equal, than in the vform of construction according to Fig. 5. With regard to the coaction of the driving pin with the walls of the slot or of the groove, the difference is that, while in the construction according to Fig. t the driving pin'slides along the inner wall of the groove up to 180", beyond 180 along the outer wall and during thel return stroke again along a part of the inner wall, and in the construe tion according to Fig. 5, during the entire forward stroke along the innerwall in two directions, and during the return stroke along a part of the outer wall of the slot, in the construction according to Fig. 5, the movement of the driving piu during the forward stroke is along the inner wall in one direction throughout, and during the rev turn stroke along the entire outer wall of the slot, the working` stroke being equal to the return stroke owing to the peculiar character of the oscillating movement in question. Hence the above described methods for improving the'ratios between working stroke and return stroke are not applicable in this case, but over the form of`construcim )roving the ratio between Workin@- stroke and return stroke, the form of construction according to Fig. 5a may be used to good advantage. Y

In the example shown the upper part of the slot has the characteristic shape 01"' an inflection curve,'ivhich is due to the circumstance that inthis case the driving pin, during the entire Working stroke, including the last rapidly rising parts of the same (Fig.

` V2)', coacts with the Yslot Within 180, While for instance, in the case of Fig. 4 the movement of the driving pin corresponding,r to the Y last parts of the stroke takes place beyond 180, 'L'. c., on the other side, which in the example shown is apparent in the approximately symmetrical return of the curve K (F ig, 4) relative to the upper part of the slot according to Fig. 5a.

In cases Where Pnm (Fig. 2) corresponds Vto, theend of the Working stroke, hence Where the diagram of Work shows only a steadily ascending` curve and not also a receding` part (pressing or stamping Work, riveting work, etc), the upper inflection part shown in Fig. 5a is dispensed with. The result is Ytherefore a still'siinpler and shorter slot generally Varc-shaped, sothat this form of construction is applicable with still better results to the above mentioned cases.

In the example according to Fig. 5@L the `outer Wall of the slot, along which the re; turn stroke takes place, is made parallel with the inner Wall for the sake of simplicity, and this shape appears suitable in many cases also with regard to the course of the velocities during the return stroke. But of course the outer slot Wall, here as'ivell as in other forms of construction, may be given any desired form corresponding to the nature of the course of the return stroke required in each case.

ln Fig. 7 is shown diagrammatically the general arrangementof a cutter (shears) arranged according to the invention for a secondary transmission briefly referred to above.

The essential'teature of the same is that the rocking lever 2, which is again rotatably mounted'on the shaft' in the trarne 3 Vand actuated bythe driving pin 5 by means of the primary slot fl, Yis not Vdirectly connected with the movable shear blade 1, but engages by means of a driving pin 11 in a slot 12 in a second lever 9, c. g., a bellcrank, like- Wise capable of rocking about its tulcrum 10 in the frame 3, Which latter lever carries sl ear blade 1. To the stroke of the latter corresponds the angle (5. lllliile the second driving pin or driver 11 describes the angle 11, 11 around the axis G, corresponding to its angle oi. deiection c1. determined by the slot 4t, said pin sliding along the upper limiting line of the secondary slot 12, the longer arm of the lever 9 describes the arc 13, 11 about its ulcrum 10, to which corresponds the angle During the return stroke the driving pin 11 slides along the lower limiting line of the slot 12.

ln the example according to Fig. S the mode oi construction of a secondary slot, with simultaneous employment ot the geometric method previously mentioned in connection with Fig. 4:, is illustrated diagrammatically. For the sake of simplicity the second driver Z is also shown as a point. In the practical construction the secondary slot S as determined must of course be widened parallel with itself according to the diameter of the pin Z.

ln the example accordingto Fig. S let it be assumed that the curve K serving as primary member does not accurately correspond to the diagram of ivork for the rea sons stated in connection ivitli Fig. 5, and that therefore, for this or some other reason. an improvement in the transmission or an intervention of some kind is to be brought about by means oi a secondary slot. On the arc of oscillation B or' thc primary lever carrying the curve K, is shown the course O, 1, 2 13 of the stroke sections, which course is brought about by said curve and for some reason does not correspond exactly (or in some cases but very little) to the diagram of Work or to momentary requirements, while the exact course actually iequired 0, 1', 2', 3 1?/ ot the stroke sections is shown on the arc oi oscillation B., oi the bellcrank lever (Fig. 7) rotatable about the axis Cl.. and constituting the tool holder. The driving pin Z of the primary lever rotatable about thc axis CG and engaging in the secondary slot S to be constructed, describes during the 'forward movenient @-13 of the main driving pin on the circle M the ai'c B1, the radius and divisional points 1, 2, 3 of which agree ivith those ot' the arc B. The diiierent points 1, 2, 3, of the secondary slot S must be determined geometrically in accordance with the requirement that, ivhile the pin Z describes the stroke sections O-l., 1-2, 2-3, etc., on the arc B1, the tool holder must describe the stroke parts 0-1, 1-2, 2-3, etc., on the arc B2. Consequently there is laid out at all points, in the-same manner as most clearly shown at point 13 of the arc B1, on the arc drawn through the points of the latter about the center C10 (paths of the points ot the secondary slot),^the distance a: measured in the arc (in the example, of point 13) from the radius drawn through the respective point (in the example through 13') of the B2 from the center C10, downward from the line t (initial position of tool holder). In the same manner the points of the lower limiting line, corresponding in each case to the required return stroke, of the secondary slot S are determined. In the present case it has been assumed, for instance, that in place of the course of the return stroke resulting fromthe primary curve K and indicated by the points 14, 15, 16 on the arc B, the course of the return stroke indicated by the points 14', 15', 16' on the arc B2 is desired.

In this manner any greater or less inaccuracy of the primary transmission may be entirely eliminated by a secondary, or, if

desired to meet further requirements, by a tertiary slot, etc., and it becomes possible, in the manner indicated above, by such additional slot to take into account any given special casesfor to al'ect the course of the working ratios at any given points and to any given extent. In Fig. 9 the measure in which such influencing by a secondary slot is possible is very clearly illustrated in an example, the geometric method of construction being the same as that of Fig. 8.

In this case the curve S1 represents the geometric middle line of a slot which would transmit the movement brought about by the primary curve K to the tool holder without any change,i. e., with unchanged course of the same. In this case therefore, which is chosen merely for the sake of explanation, the sudivision of the arc B2 agrees perfectly with that of the arc B or B1 respectively, while S2 represents the line of the desired secondary slot which produces at the tool 4holder the stroke sections corresponding exactly to the desired diagram of work. For the sake ot simplicity only that part of the Vsecondary slot is shown which corresponds to i Ac'omparison of the two curves S1 and S2 will at once show the measure of the inluence of the secondary slot, as distinguished `from the" primary transmission, at

each point of the two parts or the working stroke. It will be seen that the secondary slot S, instead of being a flat curve f3, (in certain cases it may also be a straight line) has in the presentcase a wave-like form, in which the trough of the wave corresponding about to the iirsthalt of the working stroke, comes to lie below the line S1, while the crest of' the wave, corresponding about to the second half of the working stroke, comes to lie above the line S1. v

As previously stated, by varying the shape of the secondary slot it becomes possible to intervene variably in the course of the working factors,as desired in special cases, either for the entire stroke or :tor any given part of the same. An example in this particular is also diagrammatically indicated in Fig. 9. It greater speed is desired at the beginning of the working stroke, other conditions being equal, the flat part S'2, being the rst part of the curve S2, may be replaced by the part S0. For such different cases nothing more is required than to exchange the secondary slot in the below described manner, retain ing unvaried all the other parts of the machine.

A similar case arises when work is to be done on blanks in large numbers or in groups, where the general conditions remain the same (same class of work, same blanks, same material, etc.), a change occurring merely with regard to certain dimensions, for instance, passing from the production of holes in a plate of a certain thicknessto the production of holes of larger diameter in a plate of less thickness, or vice versa. In this case the course of the work may be the same except that the length oi the stroke is varied according to the lesser or greater thickness of the plate.- The variation in the length of the stroke may be brought about in a manner not new in itself by an adjustable arrangement of the driving pin 5 (Fig. 7) of the primary lever or of other parts, e. g., by a multiple adjustable lever 2, etc. But in accordance with the invention the length of the stroke is preferably varied in a simple manner by using a different secondary slot (or additional slots), as indicated, for instance, in Fig. 10, where again all the remaining parts may be retained unchanged, the only measure required being the exchange of the slot.

According to Fig. 10, one passes, for instance, rom the slot 12, previously used, to another slot 12', drawn in dotted lines, by exchanging in the below described manner a part of the lever 9, which slot 12', generally result is a shorter length of stroke, z'. e., a correspondingly higher transmission of forces.

The modifications ormeasures described in connection WithV Figs. Z to 10 may of course also be applied to the case of a lever drive, after the manner of the embodiment according to Fig. 5, when some intervention in the course of the Working-stroke or any part thereof, or a special course of the return stroke, ete., is desired.

As regards the exchange of the slot, either one or the other slot (primary, secondary, etc.,) or all the slots may be exchangeably arranged, so that one and the same machine can be used for the most varied conditions of Work, retaining the economic method of operation,- corresponding to the diagrams of the Workingfactors.

ln Figs. 11 and 12 an advantageous form of construction of the exchangeable arrange ment of the slot-e. g., a primary slot-is illustrated. Fig. 11 is a front view and Fig. 12 a section on line A-A of Fig. 11.

vThe slot 4 is formed in a special part 14 of the lever 2, which latter is recessed in accordance with said part 14. Such recess is preferably stepped V(see the right side of Fig.v 12) Vand the part 14 provided with a `corresponding circular ange 15, so that said part 14 can be countersunk in the lever 2. The countersunk part 14 may be secured by means-of any `releasable fastening device (screws, clamping springs, etc.). In the Vexample shown the part 14 is provided on one side with one or more projections 16 in the nature of threaded bolts capable of being secured to the lever by means of Winged nuts-17 or the like. The Winged nut is like- Wise so arranged as to becountersunk in a circular recess the part 18 of which is located in the exchangeable part 14, While the other part 18, adjacent to the part 18 and forming with the same a circle, is located in the lever 2.

The drive described may also be used to good advantage for universal machine tools. Fig. 13 shows an example of such construction. In this example the primary rocking lever. 2 carries pins 11, 19 and 2O which engage in corresponding (secondary) slots 12, 21 and 22 respectively in rocking levers 9, 23 and 24 respectively, Which are mounted in the machine frame 3, only partly shown, and rotatable about pins 10, 25 and 26 respectively. The lever 9 constitutes the tool holder for a pair of shears 1, While the levers 23 'and 24 are pivotally connected, e. g., With the tool holders of a punching machinerX (not shown, merely indicatedby Van arrow) and of'a vertically guided ironvshape cutter Y or the like.

ln'this manner the requirements for economic Werk, referred to in the beginning, may be met in a very compact manner in a single machine frame and by joint drive for various machine tools.

The subject of the invention may of course be varied in many ways as regards details of construction and application. In place of an oscillatingl loop, (link,) a rotary loop (link) with curved slot may of course be used, or the tivo may be connected back of e: ch other in a manner not new in itself or combined With each other in any desired manner. lin place of a slot, a groove or other kind of curved surface may be employed, as previously stated. 'l`o insure accurate operation, care must of course be taken to have all the movable parts suitably mounted and guided. To secure rolling friction in place of sliding friction, the driving pins or drivers may be fitted With a roller, and the latter, or the slot, may be toothed or corrugated, etc.

Claims:

1. A machine, comprising a driving member, a tool operating member, and a variable driving` connection between said members, said connection including cooperating parts, so related that the rate of movement of said tool operating member ivill vary relatively to that of said driving member, the variation being such that substantially equal increments of Work will be effected during equal increments of movement of said driving member throughout the working stroke of said tool.

2. A machine tool comprising in combination, a driving member operating at a constant rate of speed and having a working capacity computed on the basis of the area of the diagram of work resistances, a toolholder, and means for transmitting the motion of the driving member to the toolholder, said transmitting means including parts so related as to cause the tool-holder to operate under a varying force in accordance With the varying resistance offered by the Work.

3. A structure according to claim 2, in which the transmitting means includes a member having a slot which is curved in accord with the Woilr-resisting factor and cooperates ivith the tool-holder.

4. A structure according to claim 2, in which the transmitting means includes a plurality of coperating members, having slots by which they are operatively connected, and Which are curved so as to move the tool-holder in accord With the Work-resisting factor.

5. A structure according to claim 2, in which the transmitting means includes a member having a short curved slot, formed in such a manner as to move the tool-holder under a varying force in accord with the varying resistance of the Work, and to return it quickly to initial position.

6. A machine, as specified in claim 1, in

which the driving connection includes a swinging member, driven by said driving member, and forming a secondary driver for said tool operating member.

7. A machine, as specified in claim 1, in which the driving member is a constantly rotating body, having a driving element to engage curved surfaces of the member to be driven thereby.

8. A machine, as specified in claim 1, in which the coperative parts of said driving connection comprise a contact element, carried by one of said mem-bers, and curved surfaces carried by the other, to be engaged thereby, the variation in the movements of said members being dependent upon the forms of said surfaces.

9. A machine, as Specified in claim 8, in which the curved surfaces are of such form as to cause a relatively large proportion of the movement of the driving member to be utilized for the Working stroke of the tool, and a relatively small proportion for the return stroke.

10. A machine, as specified in claim 8, having interchangeable parts, carrying curved surfaces, of different forms, to provide for Work on different vvorkpieces, as to which the respective resistances at different parts of the Working stroke are different.

ll. A machine, as specified in claim 6, having a plurality of tool operating members, operatively connected with said secondary driver, to be driven thereby.

In Witness whereof, I have hereunto signed my name in the presence of tWo subscribing Witnesses.

Dn. ARMIN TETTLENI.

Witnesses ARTHUR TAKLos, ALEXANDER KAUFFMANN.

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