US2007231A

US2007231A - Duplicating machine

Info

Publication number: US2007231A
Application number: US518528A
Authority: US
Inventors: Wall Edmund Leo
Original assignee: R W GLASNER
Current assignee: R W GLASNER
Priority date: 1931-02-26
Filing date: 1931-02-26
Publication date: 1935-07-09
Anticipated expiration: 1952-07-09

Description

Filed Feb. 26, 1951 6 Sheets-Sheet 1 INVENTOR ECL. 112 1!, BY 2 ATTORNEY July 9, 1935. A 7 2,007,231

' DUPLICATING MACHINE Filed Feb. 26, 1931 6 Sheets-Sheet 2 INVENTOR ELL HQ u,

' WITNESS ATTORNEY July 9, 1935. E. WALL DUPLICATING MACHINE Filed Feb. 26, 1951 6 Sheets-Sheet 3 all, 9%

lll l| INVENTOR ATTORNEY WITNESSES a hie/mm.- I

Filed Feb. 26. 1931 s t -s t 4 INVENTQR EL- all;

ATTORNEY WITNESSES July 9, 1935.. E. 1.. WALL DUPLICATING MACHINE Filed Feb. 26, 1931 6 Sheets-Sheet L. nan, BY

ATTORNEY INVENTOR .1),

- W lTNESSESa Patented July 9, 1 935 UNITED" STATES PATENT OFFICE DUPLIGATING MACHINE ner, Chicago, Ill.

Application February 26,1931, Serial No. 518,528

20 Claims.

This invention'relates to improvements in duplicating machines, and it consists of the constructions, combinations and arrangements herein described and claimed.

An object of the invention is to provide a duplieating machine which is mechanically controlled and operated, an outstanding purpose being to enable the reproduction in steel or other material either hard or soft of a pattern made of a relatively soft substance, this advantage being possible by virtue of the low tracer pressure which enables the traversing of the pattern by the tracer without marring the contours thereof, no matter how delicate.

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawings in which Figure 1 is a front elevation of the improved duplicating machine.

Figure 2 is a detail sectional view of the chuck for the milling cutter, parts being shown in elevation.

Figure 3 is a somewhat enlarged front elevation of the machine particularly showing the movable carriage and its carried parts.

Figure 4 is an end elevation of the machine, a part of the bed frame being shown in section.

Figure 5 is a horizontal section taken on the line 55 of Figure 4.

Figure 6 is a vertical section taken on the line 6-6 of Figure 3.

Figure 7 is a vertical-section taken on the line 1-1 of Figure 6.

Figure 8 is a section taken substantially on the line 8-8 of Figure 6, particularly illustrating the means for reciprocating the main carriage (Fig. 1).

Figure 9 is a cross section taken on the line 99 of Figure 8. V

Figure 10 is a longitudinal section of the tracer mechanism, parts being shown in elevation.

Figure 11 is a cross section taken on the line ll-Il of Figure 10.

Figure 12 is across section taken on the line l2-l2 of Fi ure 4. I

Figure 13 is a detail longitudinal section of the cylinder operating in conjunction with the work fcutter, taken substantially on line l3-l3 of Figure 5.

Figure 14 is a detail section taken on the line I l-l4 of Figure 5, illustrating the swivel mounting of the bevel gear by which the cutter spindle is driven.

Figure 15 is a detail elevation of the reversing valve.

One of the specific purposes of the du plicating machine is that of die sinking, and although this is used for the instant illustration, the purpose is not to be construed as thus limited because the machine can be employed whenever it is desired to reproduce a given pattern. The prevailing practice in machines of this kind is to require a pattern of hardened steel so that the relatively high pressure imposed on the tracer may not spoil the characteristics of the pattern and thus produce faulty work.

Although the instant machine embodies a number of novel features which have distinct advantages in its operation, yet the outstanding purpose is to make possible a reproduction in hard steel or other hard material from a relatively soft pattern such as a plaster of Paris cast. This facility obviates the need for a hardened steel pattern, and it also carries with it the requirement that the tracer pressure shall be such as not to mar the contour of the pattern. Notwithstanding the delicacy of touch of the tracer, its coupled cutter is made to always maintain a proper working position against the work or reproduction.

The foundation of the machine comprises a table I (Fig. 1) which is supported above the floor by legs 2. A pair of parallel rails 3 (Fig. 4) is fixedly mounted on this table. The outer faces of these rails are provided with V-grooves 4 (Figs. 4 and 6) which extend full length (Fig. 1) thereof. A T-slot 5 in the foremost rail .(Fig. 1) and coextensive therewith provides the means for adjustably securing right and left stops 6, I.

These stops will be adjusted in accordance with the length of the pattern 8 (Fig. 4) which is intended to be traced for the reproduction of the work 9. Each stop is provided with a bolt l 0 (Fig. 6), the head ll of which occupies and rides the slot 5. A nut I2 on the threaded end of the bolt enables clamping the respective stop in position.

An upright l3 (Fig. 1) provides the mount for the pattern 8 and work 9 .(Flg. 4). The upright I3 is fixedly supported by the table I in any appropriate way. The upright might be independent of the table, but in any case it should be heavy enough and secured tightly enough to remain absolutely firm during the operation of the machine. This is necessary in order that the work 9 (Fig. 4) may be a faithful reproduction of the pattern 8.

The details of both the pattern 8 (Fig. 4) and work 9 are purposely omitted because of the wide variety of forms that these may take in practice. For the present consideration it is sufiicient to say that the pattern 8 is composed of some relatively soft material, for example a plaster cast. On the other hand, the work 91s regarded as a steel block.

The manner in which the pattern 8 (Fig. 4) is traced is as follows:-A tracer |4 (Figs. 4 and 10) is made to bear at its point on the surface of the pattern by a spring |5 (Fig. 10) which acts through the medium of a number of interposed elements and abuts a barrel l6 which is adjustable so that the spring tension can be varied.

The barrel I6 is screwed into a head H which closes the right end of a cylinder l8 (Fig. 10). The left end of this cylinder is closed by a cap l9 (Fig. 10) which has an enlarged opening l9 providing adequate clearance for the necessary side motion of a protruding shank 20 by which the tracer I4 is removably carried. It is necessary to replace the tracer I4 when different shapes and sizes are required.

A combined piston and balanced valve occupies the cylinder |8 between its end closures. The piston components are denoted 2|, 22. These are integral with a sleeve 23 which carries a circular valve plate 24. This valve plate occupies an annular chamber 25, and it is against one edge 26 that the valve plate seats in order to cut oil the flow of pressure fluid. The edge 26 is, therefore, a valve seat. The cap I9 is additionally used for adjusting the valve plate 24 at the seat 26. The cap I9 is secured in position by a lock nut l9 (Fig. 10)

An inlet 21 (Fig. 10) communicates with the chamber 25. Fluid is thus introduced into the cylinder |8 between the piston components 2|, 22. Since the upright portions of the component 2| and plate 24 as well as that part of the sleeve 23 occurring therebetween constitute movable walls of the chamber 25 it follows that a movement of the so-called piston-valve may occur to the right without the necessity of the valve plate 24 having to act against fluid pressure.

In other words. when the valve plate 24 is seated (Fig. 10) the various walls consisting of parts of the component 2|, sleeve 23, cylinder I8 and plate 24 will confine a volume of pressure fluid which is readily displaced by a movement of the tracer l4 to the right, the only resistance being the tension of the spring l5. Therefore, when the tracer encounters a raised place in its horizontal travel along the pattern 8 (Fi 4), the tracer l4 will be displaced with the utmost ease. The pressure of the tracer I4 is regulated by the barrel I6 (Fig. 10), and may be made so light that even the softest pattern ordinarily employed can be traced without injury.

A fluid outlet 28 (Fig. 10) communicates with the cylinder |8 on the right side of the piston component 2|. The base 29, of which a guide stem 30 is a part, is peripherally smaller than the bore of the cylinder l8 so that there may be no 0bstruction of fluid flow through the holes 3| to the outlet 28. The base 29 is screwed into the component 2| as shown.

An opening 32 (Fig. 10) completes the passageway for the fluid. When the valve plate 24 is unseated there will be a flow of fluid from the inlet 21 into the cylinder |8, through the opening 32 into the sleeve 23 and out of both the holes 3| and outlet 23. A cup 33 (Fig. 10) has a rim with a sharp seating edge bearing against the disc 34 of the shank 20. A part of this cup has an opening 35 which provides a drain passage to accommodate oil seeping past the sleeve 23 at the component 22.

There is a separation between the cup 33 and disc 34 (Fig. 10) but the two parts are generally kept in contact by virtue of the engagement of the tracer H with the pattern and the pressure of the spring |5 in that direction. The tendency of the spring is to keep the disc 34 pressed against the flange 36 (Fig. 10) of the cap IS. A bushing 31 clamps a flexible washer 38 in place, the purpose of this being to prevent the leakage of fluid.

It is conceivable that in tracing the pattern the tracer M will suddenly ride upon an eminence and drop into an adjacent depression as suddenly. In the first instance a bodily movement to the right occurs in the direction of arrows a, but the spring |5, having to move the interposed mass of the sleeve 23 and its appurtenances might not be prompt enough to flll the sudden requirement of the tracer H. The valve 88 (Fig. 3) is adjusted to such a position by the operator as to diminish the speed of the carriage 18 (Figs. 3 and 4) relatively to the extreme movements of the tracer M (Fig. 10), the spring |5 immediately following and preventing a complete gap between the bearing points of the cap 33 and disc 34 as well as flange 36. Thus it can be seen that there is a harmonious action between the spring I5 and the pressure of the tracer |4 against the pattern 8. The point of the tracer must always be kept against the pattern.

The manner in which the cutter is made to keep pace with the tracer I4 is as follows:- The I cutter 39 (Fig. 4) may be regarded as any type of cutter suitable to remove material from the work 9. Since the latter is regarded as consisting of steel, the cutter 39 will be a milling cutter. This cutter is held in position by the jaws of a chuck 40 (Fig. 2) which is operated by a draw bar 4|. This draw bar is only slightly shorter than a hollow spindle 42 (Fig. 5) in which it can be turned by means of a head 43 (Figs. 1 and 13) in front of the machine. The spindle includes a tapering bore 44 (Fig. 2) into which the shank of the chuck is drawn when the head 43 is turned in one direction. The result is a clamping of the cutter 39.

Bearings 45, 46 (Fig. 4) support the spindle 42 which is revolved by a bevel gear 41 swivelly supported by a third bearing 48. The spindle carries bushings 49 (Fig. 2) at each of the bearings. these bushings revolving in the bearings. Both the bushings and the corresponding bores are tapering. Nuts 50, 5| on the exposed ends of'each bushing (Fig. 2) provide for adjustments of the bushings in reference to the bearings, the nut 5| also serving to clamp the split end of the respective bushing in position on the spindle 42.

A longitudinal keyway 52 (Fig. 5) in the spindle 42 receives a key 53 Fig. 14) in the hub of the gear 41. This connection compels the revolution of the spindle 42 yet permits the necessary sliding in reference to the axially stationary gear. Rotary motion is derived from the pulley 54 (Fig. 1) of a motor 55. this being transmitted through a speed reducer 56, and gear and shaft connec tions commonly denoted 51. One of the shaft components 5| (Figs. 1 and 3) has a longitudinal groove 51 receiving a spline 51 of its companion gear 51 This arrangement compels turning but permits relative axial movement of the shaft 51. The spindle 42 and consequently the cutter 39 are thus rotated during the operation of the machine.

A cylinder 58 (Fig. 13) has a boss at one end with an opening 59 both for the inflow and outflow of fluid. This cylinder has only this one fluid opening and it is connected by means of a pipe 88 (Fig. l) with the inlet 21 (Fig. of the cylinder I8. The outlet 28 of the cylinder I8 has connection by means of piping 8I (Fig. 1) with a sump 82 into which exhaust fluid is discharged.

The cylinder 58, which may be identified as the cutter cylinder by virtue of its association with the cutter 39 contains a sleeve 83 (Fig. 13)

in which the spindle 42 is slidable, and a piston 84 which worksin the annular space between the bore of the cylinder and the outside of the sleeve 83. This piston has connection with the spindle 42 by means of a yoke 85. The place of connection is made through a ball thrust bearing 88 which works with equal effectiveness in either axial direction.

An appropriate pump 81 (Fig. 1) recirculates the fluid in the sump 82, discharging this fluid into a main pipe stand 88 (Fig. 1) from which a branch 68 supplies the pipe 88. A valve 18 is connected in this branch, enabling a regulation of the pump pressure in the pipe 88 and consequently in both the cylinders I8 (Fig. 10) and 58 (Fi 13).

Fluid in the pipe 88 (Fig. 1) under pump pressure keeps the piston 84 (Fig. 13) pressed to the left and the cutter 38 (Fig. 4) against the work 8, and the manner in which the cutter 38 recedes from the work in agreement with the recession of the tracer I4 is as follows:--Assume the tracer point to be occupying the low normal plane 1i (Fig. 4) This is as low as the tracer point will go. The valve 24 (Fig. 10) is closed on its seat 28. Fluid under pump pressure keeps the cutter 38 pressed against the work through the medium of the piston 84 (Fig. 13) as already outlined.

The travels of the tracer I4 are horizontal. Suppose that it rides up on a high place. The valve 24 (Fig. 10) becomes unseated correspondingly. and fluid immediately flows through the cylinder I8 and out at the outlet 28 into the piping 8| (Fig. 1), hence to the sump 82.

This reduces-the pump pressure in the pipe 88. A weight 12 (Fig. 1) is connected by means of a cable I3 with aslide plate 14 (Fig. 4) which is transversely slidable in ways I5. The cable is guided over sheaves 18. These, as well as most of the remaining supports are mounted on a longitudinally movable carriage 17. This carriage includes a base 18 (Figs. 4 and 6) with appropriately shaped tongs l8 riding in the V-grooves 4 of the rails 3.

The weight [2 always tends to pull the cutter 38 away from the work. Fluid pressure in the cylinder 58 (Fig. 13) tends to prevent this. Reverting to what was said before, unless there is some pressure relief in the pipe 68, the weight will not draw the cutter away from the work..

When the pressure is relieved, as previously stated, the cutter 39 will recede from the work a distance agreeable with the amount of relief, and this distance will be the same as theamounut of recession of the tracer point I4.

Should the tracer point rise higher or recede farther-from the pattern 8, the correspondingly greater pressure relief in the pipe 88 would enable a correspondingly greater recession of the cutter 38 from the work 8. Should the tracer point drop low again, the restriction of the fluid flowset up between the valve 24 and its seat 28 (Fig. 10 would increase the fluid pressure in the pipe 88 so that the piston 84 (Fig. 13) and consequently the cutter 39 (Fig. 4) would be driven to a new forward position. It is thus that a faithful fluctuation of position of the cutter 39 occurs in agreement with the tracer I4 through the medium of an inter- -and forth in a driver cylinder 85.

controlled by the'tracer.

The tracer I4 and cutter 88 (Fig. 4) are caused to traverse. the pattern 8 and work 8 (Fig. 4) along horizontal and parallel lines, and the manner in which this is accomplished is as follows:-- The carriage 11 includes a head 88 (Fig. 3) which is permanently secured in or to the base 18 (Fig. 6) by any conventional means such as machine screws 8|. This head has a rod 82 (Figs. 3 and 8) connected to it as at 88. This rod carries a double headed piston 84 (Fig. 8) which works back This cylinder is fixed on the table I.

A branch 88 (Figs. 1 and 3) delivers fluid at pump pressure to an inlet channel 81 (Fig. inside of the head 88. A valve 88 controls the inflow. The channel 81 communicates with a chamber 88 (Figs. 6 and 15) in which a valve disc 88 turns. This disc has a stem 8I which loosely carries a tripper 82. The tripper is engageable with the stops 8, 1 (Fig. 1) when the carriage II nears the end of its movements, thus turning the disc 88 (Fig. 15) to new positions.

Right and left ports 88, 84 (Fig. 15) extending completely through the disc 88, alternately provide communication of the chamber 88 with right and left passages 95, 88'(Fig. 8) in the head 88. These passages connect with longitudinal passages in the rod 82 (Fig. 8). The longitudinal passes terminate at opposite sides of the double headed piston 84 where they are fitted with

outlets

81, 88 which are directed upwardly.

The

passages

85, 88 are narrowed where they connect with the chamber 88 (Fig. 6) to the approximate shape of the ports 83, 84. Therefore, when the latter communicate with the

passages

85, 88 the pressure fluid will be introduced directly into one or the other of the passages, with no possibility of leakageto an exhaust channel 88 on back of the disc 88, or to an exhaust passage I88 with which the channel 88 is in constant communication.

The channel 88 is arcuate in shape. It covers the inlet to one of the

passages

85, 88 while the other is in registration with one of the ports 83, 84. For example, the present setting of the disc 88 (Fig. 15) is that of registration of the right port 83 with the right passage 85. The left port 84 is out of registration with the inlet to the left passage 88 but this is covered by the exhaust channel 88. Pressure fluid is, therefore, admitted to the channel 85. This is discharged into the cylinder 85 (Fig. 8) at the outlet 81. Pressure at the left side of the piston 84 drives this to the right, arrow 0, consequently moving the carriage 11 to the right (Fig. l), arrow (1. The motion of the carriage will be reversed when the tripper 82 strikes the stop 8. This will reverse the valve disc 88 (Fig. 15).

A double arc-shaped hole I8I (Fig. 15) in the valve disc 88 and a matching recess I82 (Fig.6) in the base 18 receive the narrow blade I83 of the stem 8|. The blade has lost motion in the hole and recess. The purpose is to delay the switching of the pressure fluid to the left passage 88 (for example) until the full motion of the carriage 11 (Fig. 1) to the right has been completed. The initial rocking of the tripper 82 (Fig. 1) upon engagement with the stop 6 will be absorbed in loosely turning the blade I83 in the hole I8I (Fig. 15). The turning of the disc 88 will be sudden. The pressure fluid will Shifting of the stem 9|, consequently of the disc 90, is accomplished by the tripper 92 through the medium of pins I04, I05 (Fig. 3) which are engageable with the arm I06 of a weight I01, the.

arm being secured to the stem 9|. Assume the tripper 92 (Fig. 3) to be riding against the stop 6 (Fig. 1). The pin I04 will elevate the weight I01 until it reaches dead center. The blade I03 will turn loosely in the hole IOI (Fig. 15).

When the dead center is passed, the weight I01 will fall to the right. The blade I03 will suddenly turn the disc 90 so as to switch the pressure fluid to the left passage 98,.whereupon the carriage 11 will be suddenly reversed. In falling over, the arm I08 will strike the pin I05 (Fig. 3) and suddenly move the tripper 92 to its opposite angular position I08 (Fig. 1) which position was previously vacated by the riding of the tripper 92 against the stop 1.

A bushing I09 (Fig. 6) provides a bearing both for the stem 9I and the tripper 92. For the purpose of this bearing the tripper 92 is formed into a plate H which is not only a complement to the hearing but also a mount for the pins 14, A spring III (Fig. 6), fitted between the bushing I09 and valve disc 90, presses the latter to its seat on the bottom of the chamber 89. The exhaust passage I00 (Figs. 6 and discharges to the sump 62 by means of a pipe I I2.

The tracer I4 and cutter 39 (Fig. 4) are simultaneously lowered or spaced downwardly a predetermined distance at the end of each right and left movement of the carriage 11 (Fig. l), and the manner in which this is accomplished is as followsz-The previously mentioned slide plate 14 (Fig. 4) is carried by a head II3 (Figs. 5 and 12) of which the ways 15 are a part. This head travels up and down on guide ribs I I4 (Figs. 4 and 5). These ribs are a part of the carriage 11. The tracer I4 and cutter 39 are firmly connected by a coupling bar II5 (Fig. 4). This is secured to the bearing 45 (or elsewhere on the slide plate 14) and has a clamp H6 in which the tracer cylinder I8 is rigidly gripped.

A control valve II 1 (Figs. 3 and 6) occurs as an extension of the head II3 for which purpose it includes a flange II8 (Figs. 3 and 7) through which connection is made to the head II3. A screw shaft H9, immediately behind the control valve II1, carries a nut I which coacts with one end of a valve member I2I (Figs. 6 and 7). The nut I20 rides in a groove I22 (Fig. 6) in the adjacent carriage 11 and is thus kept from turning.

The bottom end of the screw shaft H9 is squared at I23 (Fig. 6). This square end fits in a corresponding recess in a step gear I24. This gear has bearing at I25 on the base 18. The bearing of the gear is, therefore, the bottom hearing of the screw shaft. The upper part of the shaft has bearing elsewhere on the carriage 11 (Fig. 3), and this part carries a crank I26 by which the shaft is manually turned to the right (looking down), thus to elevate the nut I20 and the head I I3 to the starting position of the tracer I4 and 39 at the top of the pattern 8 and work 9.

Intermittent turns to the left (looking down) are imparted to the screw shaft I I9 by a link I21 (Fig. 3) which connects the plate I I0 with an actuator I28. The left end of the link I21 is permanently pivoted to the plate II 0, but the pivot I29 at the right end is variously adjustable at I30 so that the uniform stroke of the link I21 may be varied in its effect on a pair of meshing gears I3I, I32, the last of which meshes with the step gear I24.

Dogs I33, I34 engage the respective gears I 3I, I32 as shown. These are carried by articulated connections I35 of which the actuator I28 is a part. A rocking motion of the actuator I28 in either direction will revolve the step gear I24 to the left (looking down) with the result that the head I I3 is lowered in even stages, the successive lowering movements occurring at the ends of the longitudinal movements of the carriage 11.

It is not to be understood that the counterclockwise turning of the screw shaft II9 of its self forces the head I I3 down. This turning of the screw shaft II9 causes an operation of the control valve H1, and this operation of the control valve causes the head I I3 to lower. To this end the head II3 surmounts a hollow piston rod I36 (Fig. 4), which has a piston I31 (Fig. 1) operating in a fixed cylinder I38. The passage I39 of the hollow rod communicates with the space below the piston, and this space is filled with fluid. As long as a given volume of fluid remains constant in the cylinder and the passage I39 remains closed, the piston I31 and its appurtenances will be immovably supported.

Ducts I40, I4I, I42 in the control valve II1 (Fig. 7) are arranged to have certain communication through openings or seats I43, I44. The

valve member I 2| has a valve to normally engage 1 both seats I43, I44, that is to say, while the carriage 11 is in the course of one of its longitudinal movements, but also to engage only one of the seats at a time, for example, I43 as in the lowering of the head H3 and I44 as in the raising thereof. 3

The central duct I has permanent communication with the passage I39 (Fig. 3) by the medium of a pipe I46. A spring I41 (Figs. 6 and '7) presses on the valve member I2I and keeps it in contact with the nut I 20. Fluid under pump pressure is delivered to the duct I by way of piping I48 (Fig. 3). The supply may be cut off by a valve I49. Exhaust fluid is delivered to the sump 62 (Fig. 1) from the duct I42 (Fig. '7) by way of piping I 50 (Fig. 3) which makes connection with the piping SI.

Assume the control valve H1 and the head II3 (Fig. 3) to be at rest so far as vertical movement is concerned. The valve part I45 assumes the medial position between the seats I 43, I44, closing both (Fig. '1) and thus preventing an escape of fluid from the cylinder I38 (Fig. 1) by way of the passage I39, piping I46 (Fig. 3) and duct I4I (Fig. 7). This is the normal position of the valve member I2 I, and the head I I3 is sustained by the incompressible temporarily fixed-volume fluid column.

Assume that the carriage 11 has reached the end of its movement to the right (arrow (1, Fig. 1). The same action of the tripper 92 which causes the reversal of the valve (Fig. 15) hence of the carriage 11, also imparts a counter-clockwise turn to thescrew shaft I I9. The nut I20 (Fig. '1) tends to depart from the valve member I 2|, but the valve member follows by virtueof the spring I41. Assuming the nut to have lowered to the position I5I (Fig. '7), the valve part I45 will be correspondingly lowered so that communication of the duct MI is established with I42 through seat I44.

Inasmuch as the weight of the head I I3 and its carried parts is concentrated on the piston I 31 (Fig. 1) it follows that fluid will be discharged up the passage I39, through the pipe I46 and ducts I4I, I42 into the sump 62 by way of piping I50,

III

6|. The result is a lowering of the head H2.

-The control valve III lowers with it. The nut I20 makes but a limited downward movement, hence becomes a fixed abutment for the valve member'I2I. When the seat I44 (Fig. 7) reaches the valve part I45, communicationwith the duct I42 is cut oil, hence the head III again becomes immovable.

When the head I I3 has finally reached its lowermost level it will become necessary to raise it to the starting position, and this is accomplished in the following manner:-The crank I26 is continuously turnedglockwise during the raising action. The consequent clockwise turning of the screw shaft I I9 (Fig. 6) keeps the nut I20 pressed up in the approximate position I52 (Fig. 7). The valve part I45, being raised in reference to the seat I43 admits fluid from the duct I40 at pump pressure to the duct I and ultimately to the bottom of the cylinder I38 (Fig. 1). The pressure elevates the piston I81 and its superimposed head II3.

Upon ceasing to turn the crank I26 and screw shaft II9 there will be a brief departure of the control valve I I! (Fig: 7) from the now stationary nut I20. this by virtue of the pressure fluid still entering the duct I" and cylinder I38, whereupon a closure of the seats I42, I 44 will soon occur with a consequent stopping of the movement of the head H3.

The operation is readily understood. A pattern 8, (Fig. 4) of any description is suitably mounted on the upright I3 (Fig. 1) in common with the work 9 which may be a block of steel or such other material in which the pattern is desired to be reproduced. The carriage IT as a whole is moved back and forth along the parallel rails 3. The movement of each direction is automatically stopped by the rocking of the tripper 92 (Fig. 1) when engaging the stops 4, I at the extremities of the right and left movement. These stops are adjustable by means of the nuts I2 so that the amplitude of the carriage movement can be made as great or as small as the longitudinal dimension of the pattern 8 demands.

Assume the carriage 'I'I tobe traveling toward the right (arrow d, Fig. 1). Turning of the tripper 92 causes the pin. III4 toraisethe arm I06 to the erect position. Considerable lost motion is taken upin the double arc-shaped hole IIII (Fig. 15) of the valve 90, but as soon as the arm I06 reaches the dead center it will fall over and quickly reverse the position of the valve 90. Up to this time pressure fluid admitted at the inlet 81 (Fig. 15) enters the passage 35 (Figs. 6 and 8) by way of the registering port 83 (Fig. 15), but as soon as the valve 90 is reversed, as just stated, the pressure fluid is directed tothepassage 96, whence it is discharged in the right end of the cylinder 85 .(Fig. 8) and forces the piston 84 to the left. The carriage I1 is reversed as a consequence.

Simultaneously with the reversal of the carriage 'I'I the tracer I4 and cutter 39 (Fig. 4) are dropped as a unit. Such a drop occurs at the end of each longitudinal movement of the carriage TI. The cutter 39 thus operates on the work 9 during each stroke of the carriage. The drop is caused by a shift in the position of the valve member I2I (Fig. 7)

Normally the valve part I (Fig. 7) of this member closes the seats I43, I44 so that no fluid can escape from the bottom of the cylinder I38 (Fig. 1). The piston I31 thus has a solid rest, and the superimposed head H3 and its carried parts are held stationary insofar as vertical movement is concerned.

But upon a downward shift of the valve member I2I, communication is established with the duct I42 (Fig. 7) so that fluid escapes from the cylinder I38 (Fig. 1) and the sump 62. The resulting lowering of the head H8 is promptly checked when the original and normal relationship of the valve part I45 with the seats I43, I44 (Fig. 7) is reassumed. It is thus understood that the tracer II4 and cutter 39 are successively lowered with a step motion, the steps occurring at the ends of each movement of the carriage 11.

Neither the movements of the'carriage "nor of the head II3 have anything to do with the transverse movements of the tracer I4 and cutter 39. The line II (Fig. 4) is regarded as a low normal plane which when touched by the point of the tracer I4 finds the valve 24 (Fig. 10) of the cylinder I8 closed against the seat 26; When the tracer I4 rides upon an eminence, the opening of the valve 24 lets fluid through to the piping 6I so that a corresponding diminution of premure in the pipe 60 (Fig. 3) enables a recession of the piston 64 (Fig. 13) by virtue of the constant pull of the weight I2 (Fig. 3) upon the slide plate 14 (Fig. 4) This slide plate is indirectly connected with the piston 64 by means of the yoke 65 with which the thrust bearing 86 of the spindle 42 engages.

The spring I5 (Fig. 10) is adjustable by means of the barrel I6 to any desired tension so that the pressure .of the tracer I4 against the pattern will be substantially limited to any wanted pressuresetting of the spring. For general purposes the tension of the spring I5 is set at approximately one pound. This setting of the spring has no relationship whatsoever to the pressure in the fluid system. The presence of fluid under pressure in the chamber 25 (Fig. 10) might at first indicate a tendency to assist in pressing the sleeve 23 to the left-but inasmuch as the confronting surfaces of the piston 2| and valve plate 24 are the same in area there will be an equalization of the fluid pressure against these surfaces and the valve sleeve 23 assumes a balanced condition as a consequence. The same condition obtains in the exhaust chamber at the left of the plate 24 when the valve plate has become unseated from its seat 26. 1

From the foregoing description it will be understood that the valve 24 is subject to being unseated by a direct axial pressure on the tracer I4. In other words, if the push is directly inward in line with the axis the valve 24 will become unseated. But the tracer I4 is also subject to deflections in every radial direction as denoted by the broken lines in Figure 10.

When such deflections occur the tracer I4 partakes of a rocking motion. This rocking motion is suflicient to displace the cup 33 inwardly and consequently disengage the valve 24 from its seat 26. Any point around the rim of the flange 36 may thus become the fulcrum on which the tracer I4 rocks, and when the valve 24 is displaced as stated such displacement will occur against the tension of the spring I5.

There will be continuous vibrations of the valve 24 (Fig. 10) in reference to its seat 26 in agreement with the vibrations of the tracer I4 while horizontally traversing the pattern 8. There are also movements of the cylinder I8, consequently of the cutter 39, relatively to the valve 24 (Fig. 10) because when the valve 24 is displaced by virtue of the tracer I 4 riding upon an eminence the consequent pressure reduction in the cylinder 58 (Fig. 13) momentarily enables a relative shifting of the slide 14 and cylinder I8- (Flg. 4) to the right by virtue of the weight 12 so that the former relationship of the valve 24 to its seat 26 is reassumed. Should the tracer i4 next drop into a depression, which it is as likely to do as to ride upon a fm'ther eminence, the fluid pressure in the cylinder 58 (Fig. 13) would drive the piston 64 forward to the left and cause the cutter 39 to continue drilling into the work 9 (Fight) until the tracer point reaches the bottom of the depression where the tendency of the fluid pressure to press the piston 64 and cutter 39 farther to the right would immediately be terminated by an opening of the valve 24 (Fig. 10) and a consequent diminution of the pressure in the cylinder 58.

Of course when the tracer l4 traverses a level place the valve 24 will remain still. In any case the volume of fluid passing the valve 24 is controlled by the position of the valve, the result being an exact correspondence of position of the cutter 39 with that of the tracer I4. The cutter is maintained in position between the opposing forces on the piston 64 (Fig. 13) of the weight 12 on one hand and the pressure fluid on the other.

The side motion of the shank 20 and tracer l4 (Fig. 10), made possible by the opener i9, is needed to allow full adaptation of the tracer to the pattern. When the tracer i4 reaches a projection which extends out beyond the point of the tracer said projection will cause a slight side movement of the shank 20 which must be compensated for and is compensated for by the opening I9.

When desiring to raise the head H3 to its top position, a continuous clockwise turning of the crank I26 and screw shaft H9 (Figs. 3 and 6) causes a continuous upward pressure on the valve member l2l with the result that the duct I40 (Fig. '7) is placed in communication with the duct l4l. Fluid under pump pressure is thereby delivered to the bottom of the cylinder I38 (Fig. 1) with the result that the head I I3 and its carried parts are raised.

While the construction and arrangement of the improved duplicating machine is that of a generally preferred form, obviously modifications and changes may be made without departing from the spirit of the invention or the scope of the claims.

I claim 1. In a duplicating marhine, a slide plate, pulling means tending to pull the plate in one direction, a revoluble cutter journaled on the plate, a flxed cylinder, a piston in the cylinder having means connecting the piston and slide plate together, a line connected to one end of the cylinder introducing pressure fluid against the piston to resist said pulling means, a tracer cylinder connected in said line and carried by the slide, a tracer movably carried by said cylinder, and a valve in the tracer cylinder operable by the tracer to vary the pressure of fluid in said line, hence the effectiveness of said pulling means.

2. In a duplicating machine, a coupled pattern tracer and work cutter, inert means tending to pull the couple in one direction, pressure fluid actuator means tending to push the couple in the opposite direction, a valve for controlling the fluid pressure, and opposed means for moving the valve in opposite directions, one of the said opposed means being directly controlled by the tracer for regulating the applied fluid pressure, hence the effectiveness of said inert means.

3. In a duplicating machine, a work cutter, a connected weight tending to pull the cutter away from the work, pressure fluid apparatus resisting the weight and tending to push the cutter toward the work, said apparatus including a pressure fluid line, a pattern tracer coupled with the cutter but having limited vibratory motion in reference to the cutter, a valve connected in said line being subject to the vibrations of the tracer to increase and decrease the effectiveness of said apparatus, hence decrease and increase the efl'ectiveness of the weight, tension means for pressing the tracer against the pattern, and means for varying the tension of said means.

4. In a duplicating machine, a carriage, fluid pressure operatedmeans for rectilinearly moving the carriage in opposite longitudinal directions, means on the carriage operable on the end of each movement to control the pressure to reverse the driving means hence the carriage, a pattern tracer and work cutter, a head on the carriage by which said tracer and cutter are carried, and means embodying fluid pressure actuated means operable with the reversing means, for moving the head in a transverse direction upon the aforesaid reversal of the carriage.

5. In a duplicating machine, a carriage, driver means for longitudinally and rectilinearly moving the carriage in opposite directions, a pressure fluid cylinder mounted on the carriage, a piston in the cylinder, a head superimposed on the piston, a pattern tracer and work cutter carried by the head, reversing means on the carriage acting on the driver means to reverse the driver means and periodically reverse the movement of the carriage, and valve means associated with the reversing means causing a limited fluid discharge from the cylinder upon reversal of the carriage and a consequent lowering oi. the head.

6. In a duplicating machine, a fixed driver cylinder to which pressure fluid is admissible, a second flxed cylinder from which previously admitted pressure fluid is releasable, a movable carriage, a piston in the driver cylinder having connection with the carriage, a head movable on the carriage, a piston in the second cylinder having connection with the head, a valve operable to admit pressure fluid in one end of the driver cylinder and so move the carriage in one direction, a second valve operable to release fluid from the second cylinder, and means actuated during said movement of the carriage to operate both valves respectively to switch the flow of pressure fluid to the other end of the driver cylinder and to release a portion of fluid from the second cylinder.

7. In a duplicating machine, a gravitating head, a piston and rod attached to the head having a passage opening on one plane face of the piston, a flxed cylinder in which the piston flts, containing an impounded volume of fluid on which said face rests to support the head, a valve carried by the head to control the passage, a member holding the valve hence the passage closed, and means for periodically displacing the member causing periodic opening. and closing of the valve during the resulting step gravitation of the head.

8. In a reproducing machine, a gravitating head, an attached rod and piston having a passage opening on one plane face of the piston, a fixed cylinder containing a volume of fluid supporting the head on said plane face, a valve carried by the head to control the escape of fluid from the passage, a screw shaft having a member acting on the valve to hold it and the passage closed, and means for periodically turning the shaft to displace the member from the valve for an opening thereof until the succeeding movement upon the member by the valve.

9. In a duplicating machine, a gravitating head, means impounding a flud column to support the head, a valve carried by the head to control the escape of fluid from said column, and means operating with a step motion in the direction of gravitation of the head, causing periodic openings of the valve and closings thereof as the head catches up with the last said means.

10. In a duplcating machine, a head, a tracer and cutter couple carried by the head, and an attached rod and piston, a fixed fluid containing cylinder in which the piston is movable, a valve to control the volume of fluid in the cylinder and being carried by the head, a screw shaft having a member to engage and close the valve, means to turn the shaft in one direction thus to periodically displace the member and cause successive openings of the valve for a release of fluid from the cylinder, a source of pressure fluid, and means to turn the shaft in the other direction thus shifting the valve to a pressure-conducting position for filling the cylinder and elevating the head.

11. In a duplicating machine, a work cutter, means tending to pull the cutter away from the work, pressure fluid apparatus res'sting said means and tending to push the cutter toward the .work, said apparatus including a pressure fluid line, a pattern tracer coupled with the cutter but having limited vibratory motion in reference to the cutter, a valve connected in said line, and yieldable means tending normally to move the valve in one direction. said valve being subject to the vibrations of the tracer to increase and decrease the effectiveness of said apparatus, hence decrease and increase the effectiveness of said means.

12. In a duplicating machine, a work cutter, fluid pressure apparatus to push the cutter against the work, means tending to act oppositely on the cutter and push it away from the work, a pattern tracer subject to axial and radial vibrations by virtue of the intricacies of a pattern, and a valve device for controlling said fluid pressure, said valve device being associated with and directly operated upon by the pattern tracer for causing the release from or impounding of pressure fluid in respect to said apparatus to produce movements of the cutter in either axial d rection.

13. In a duplicating machine, a work cutter, a piston coupled with the cutter, a cylinder containing the piston, a pipe line communicating at one end with the cylinder, a valve with which the other end communicates, a fluid pump connected in the pipe line imposing pressure on the piston to keep the cutter against the work, and a pattern tracer which is subject to vibration by the intricacies of a pattern to variably open the valve and cause variable drops of pressure in the pipe line.

14. In a metal forming machine, a tool to cut into the work and a support for the tool, a weight normally tending to move the tool away from the work and connections between the weight and said support, pressure fluid means normally tending to move the tool toward the work, said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the profile of a pattern through which mechanism the pressure fluid line is adapted to be by-Dassed. said mechanism having connections to the support, and a valve apparatus included in said mechanism to variably by-pass the pressure fluid from the pressure fluid means as said apparatus is vibrated by the pattern to cause the weight to predominate variably.

15. In a metal forming machine, a tool to cut into the work and a support for the tool, a weight normally tending to move the tool in one direction with respect to the work and connections between the weight and said support, pressure fluid means normally tending to move the tool in the opposite direction with respect to the work, said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the proflle of a pattern through which mechanism the pressure fluid line is adapted to be by-passedsaid mechanism having connections to the support, and a valve apparatus included in said mechanism to variably by-pass the pressure fluid from the hydraulic means as said apparatus is vibrated by the pattern to cause the pressure fluid means and weight to predominate alternately.

16. In a metal working machine, a tool to cut into the work and a support for the tool, a framework on which the support is movably mounted, a weight carried by the framework normally tending to move the tool with respect to the framework and work and connections between the weight and said support, pressure fluid means also mounted on the framework normally tending to move the tool in the opposite direction with respect to the work and framework, said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the profile of a pattern through which mechanism the pressure fluid line is adapted to be by-passed, said mechanism having connections to the support, and a valve apparatus included in said mechanism to variably by-pass the pressure fluid from the pressure fluid means as said apparatus is vibrated by the pattern to cause the weight and pressure fluid means to predominate alternately.

1'7. In a duplicating machine, a work cutter, means tending to pull the cutter away from the work, pressure fluid apparatus resisting said means and tending to push the cutter toward the work, said apparatus including a pressure fluid line, a pattern tracer coupled with the cutter but having limited vibratory motion in reference to the cutter, a valve connected in said line, tension means tending normally to move the valve in one direction and for pressing the tracer against the pattern, said valve being subject to the vibrations of the tracer to increase and decrease the efiectiveness of said apparatus, hence decrease and increase the effectiveness of the said pulling means, and means for varying the stress of the said tension means.

18. In a metal forming machine, a tool to cut into the work and a support for the tool, means operating upon and normally tending to move the tool away from the work, pressure fluid means normally tending to move the tool toward the work, the last said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the profile of a pattern through which mechanism the pressure fluid line is adapted to be by-passed, said mechanism having connections to the support, and a valve apparatus included in said mechanism to va'riably by-pass the pressure fluid from the pressure fluid means as said apparatus is vibrated by the pattern, to cause the flrst said means to predominate variably.

19. In a metal forming machine, a tool to cut into the work and a support for the tool, means operating upon and tending to move the tool in one direction with respect to the work, pressure fluid means normally tending to move the tool in the opposite direction with respect to the work, the last said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the proflle o! a pattern through which mechanism the pressure fluid line is adapted to be by-passed, said mechanism having connections to the support, and a valve apparatus included in said mechanism to variably by-pass the pressure fluid from the pressure fluid means as said apparatus is vibrated by the pattern to cause the pressure fluid means and the first said means to predominate alternately.

20. In a metal working machine. a tool to cut into the work and a support for the tool, a framework on which the support is movably mounted, means mounted upon the frame-work to move the tool with respect to the framework and work, pressure fluid means also mounted on the framework normally tending to move the tool in the opposite direction with respect to the work and framework, the last said means including a pressure fluid supply line and connections to the support, a tracer mechanism to follow the profile ot a pattern through which mechanism the pressure fluid line is adapted to be by-passed, said mechanism having connections to the support, and a valve apparatus included in said mechanism to variably by-pass the pressure fluid from the pressure fluid means as said apparatus is vibrated by the pattern to cause the first said means and said pressure fluid means to predominate alternately.

EDMUND LEO WALL.