US2068084A - Drilling and tapping machine - Google Patents

Description

Jan. 19, 1937. E. J. STAHLHAMME'R DRILLING AND TAPPING momma* Filed Nov. 29, 1933 v8 Sheets-Sheet 1 JQIL 19, 1937- E. J. STAHLHAMMER 2,068,084

DRILLING AND TAPPING MACHINE Filed Nov. 29, 1933 8 Sheets-Sheet 2 |51 1v. +9 5l -2: r1 f 5954 5 l 'I H Pfg. 2 --174 W II@ y 838k A. '39 I 9o 9| (jab H 47 l y 4% r* 9 m 'illo O @x| @o il 54 /I/ O /Q o) .53 l I o O/l l .4Z 43 44 I l i W 4I --f ,o

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E. J. STAHLHAMMER DRILLING AND TAPPING MACHINE Filed NOV. 29, 1953 8 Sheets-Sheet 5 INVENTOR Jan. 19, 1937. E. J. STAHLHAMMER 2,053,034

DRILLING AND TAPPING MACHINE Filed Nov. 29, 195s e sheets-sheet 4 Jan. i9, 1937. E. J. STAHLHAMMER 2,06884 DRILLING AND TAPPING MACHINE A Filed Nov. 29, 1953 8 Sheets-Sheet 5 Jan., 19, i937. E. .1. STAHLHAMMER 2,068,934

DRILLING AND TAPPING MACHINE Filed Nov. 29, 1933 8 Sheets-Sheet 6 @WNV 1 Jan.. i9, 1937. E. .1. STAHLHAMMER.

DRILLING AND TPPING MACHINE Filed NOV. 29, 1935 8 SheS-Sheet 7 Jan. 19, 1937. E. J. STAHLHAMMER 2,068,084

DRILLING AND TAPPING MACHINE Filed NOV. 29, 1933 8 Sheets-Sheet 8 Patented Jan; 19, 1937 UNITED STATES PATENT OFFICE DRILLING AND TAPPING MACHINE Eric J. Stahlhammer, Bridgeport, Conn., assignor to The Bodine Corporation, Bridgeport, Conn., a corporation of Connecticut Application November 29, 1933, Serial No. 700,241

22 Claims.

This invention relates to drilling and tapping machines, especially multispindle machines in which a drill or tap operates on one piece carried by one spindle of work while the other 5 tool carried by another spindle operates on the same or another piece of work, the work being usually progressively moved or indexed into position to be engaged by the tools.

In its more specific aspects, the invention relates to the operation of such a machine hydraulically.

An object of this invention is the provision of a drilling and tapping machine which is strong and sturdy in construction, so that it may perform heavy Work, considering its size and weight,

and yet be economically constructed, easily set up and adjusted for different kinds of work, and

reliable in operation.

hereinafter called the f ceding means, and means for progressively carrying pieces of work into position to be operated upon by the tools, hereinafter referred to as indexing., and certain other related mechanism.

One of the features provision of a reciproc only operates the driv of this invention is the ating carriage which` not ing means but also controls the feeding means and the indexing means.

In the disclosed form of the present invention, this carriage comprises a rack for engaging gears forming part of the driving train, and it carries cams for controlling the feeding movements of devices for controlling the tool. It also carries the indexing mechanism as well as devices for determining the length of stroke of the carriage.

The carriage is located in an easily reached position, and the cams and devices above referred to are adjusted on the carriage from the front of the machine so that the setting-up of the machine to do a particular job is comparatively easy.

In the preferred form of the present invention, the carriage is operated by a fluid-operated motor, and the movements of the carriage are *controlled by a valve operated directly or indirectly `by the adjustable devices, above referred toas being carried by the carriage.

In the preferred Iform of the present invention, hydraulically, trolling the indexing carriage to be operate by the carriage.

the indexing mechanism is also operated and the valve mechanism for conis located adjacent the d by the devices carried Others of the more important features of this invention comprise the provision of means for regulating the hydraulic pressure applied to the fluid; motor for driving the rack, the valve mechanism for controlling the fluid motor, the valve mechanism for controlling the indexing, the locking of the work support in adjusted position hydraulically, and the arrangement whereby locking and indexing mechanism are operated automatically in coordination, and other features and advantages which will hereinafter appear.

In the accompanying drawings- Figure 1 is a side elevation of a drilling and tapping machine made according to the present invention, in its present preferred form.

Fig. 2 is a vertical sectional view taken through the middle of the machine shown in Fig. 1.

Fig. 3 is a front elevation of the machine 20 'shown in Fig. 1, with the hood which extends over the driving train shown in section.

Fig. 4 is a vertical sectional view through the upper part of the frame, the carriage, and the valve mechanism for controlling the fluid motor.

Fig. 5 is a front view of the valve actuating mechanism showing the feed control cam, and means for adjustably supporting it on the carriage, the actuating mechanism being in position to move the valve lever.

Fig. 6 is a view similar to Fig. 5, showing the valve lever released and operated.

Fig. 'l is a front view of the Valve and valve actuating mechanism.

Fig. 8 is a sectional view taken on line 8 8 of Fig. 4, showing the valve and the fluid operated motor. Fig. 9 isa sectional view of the valve device for controlling the indexing. Fig. 10 is a vertical sectional view taken on the line I0-I0'of Fig. 9.

Fig. 11 is a vertical sectional view taken on the line II-ll of Fig. 9.

, transmits power from nected to a pump piston for operating the indexing lock plunger.

Fig. 17 is a detail sectional view of the valve shown in Fig. 15.

Fig. 18 is a similar view, looking at the parts from the other side` Fig. 19 is a diagrammatic view showing the manner in which the various parts of the device are connected together hydraulically.

Fig. 20 is a. sectional view of the pressure regulating valve shown in Fig. 19.

Fig. 21 is a sectional shown in Fig. 19.

Fig. 22 is a vertical sectional view through the relief valve employed to avoid the shock and vibration incident to the reversing of the carriage at the end of its movement toward the right.

As shown in the accompanying drawings, the drilling and tapping machine of the present invention comprises a frame I0 having a base II from which it rises vertically. The frame I0 is hollow and its lower portion constitutes a reservoir I2 for the fiuid employed to transmit power from one point on the machine to another. 'Ihe fluid used is preferably an oil, because it not only one point to another on the machine but lubricates the operating parts with which it contacts. Within the hollow frame I0 and mounted on a removable back plate I3 is an electric motor I4 having a drive shaft I5 con- I6 also secured to the removable back plate I3. The pump I6 has an inlet pipe I1 extending down into the oil reservoirv I2 and an outlet pipe I8 connected to the various fluid motors employed in the operation of the machine.

The casing has a side door which access to the motor may be had for oiling, inspection, etc. By having the motor and pump mounted on the back plate I3, when the latter is removed these parts come out of the frame I0 as a unit.

The front part of the frame I 0 is provided with ways 20 'on which a worktable 2I is slidably mounted and may be secured in desired position by operation of a clamp 22. To sustain the greater part of the weight of the worktable 2|, the frame is provided with a vertical screw 23 having a handwheel 24 by means of which the frame may be raised and lowered when the clamp 22 is released.

'I'he Work, which may be of any desired character, may be fed to position to be operated upon in any suitable or conventional way, that is to say, the work may be advanced on a drum, on a I9 by means of conveyor, or, as shown herein, on a turntable or.

dial 25. The dial or other work lsupport is, of course, provided with suitable fixtures for holding the work in desired position and it is rotated step-by-step in a manner hereinafter explained to bring pieces of work successively into operating position and progressively from one tool to another.

'I'he `Worktable may be provided with a tray 26 adjustably supported on an extension 21 on which a supply of work to be done may be supported in convenient position for the operator to insert in the proper places on the dial 25. As shown, the tray 26 may also be adjusted horizontally, for its depending anges 28 are slidably mounted on a horizontal portion 2B of an L-shaped piece 30 and are adjustably secured to the horizontal piece 29 by screws 3|. 'I'he worktable further has a ldraw 32 for receiving the chips thrown off by the worktable.

view of the safety valve The working tools T, which may include taps, drills, counterbores, etc., are carried by chucks 33 on spindles 34 mounted in bearings 35 having ears 36 which may be clamped to segmental mounting arms 31 which extend out from a vertically extending auxiliary frame or slide 38. Bolts 39 secure the spindle bearing arms 36 to the extension 31, and, at the same time, secure arcuate arms 40 to the extensions 31. These arms 4U are employed tosupport other spindles if and where needed. i

While it is within the scope of this invention to have the work move up and down relative to the tool, in the preferred form of this invention herein disclosed, the slide 38 carrying the spindles 34 is moved up and down to feed the tool toward and from the work.- The means for accomplishing this will be described below.

Tool drive The spindles 34 for the tools T have gears 4I at their upper ends. These engage with suitable intermediate gears 42 which ultimately engage a gear 43 carried by a shaft 44 having its lower end supported in a bearing 45 carried by the slide 38. The upper end' of the shaft 44 engages a bearing 46 carried by the upperportion 41 of the slide 38. Between the bearings 45 and 46, the shaft 44 has a barrel pinion 48 which engages with a driving member hereinafter referred to. The upper end 41 of the slide 38 is provided with a post 49 sliding in a bearing 50 carried by a bracket 5I attached to the main frame.

As above pointed out, one of the important features of this invention is the provision of a reciprocating carriage which not only drives the tools but also controls the feeding of the tools and work. This carriage, in the form of the invention herein disclosed, comprises a horizontal bar 52, a rack 53, a rod 54, and end pieces 55 securing said rods and rack together in parallel relation. The carriage is guided for movement horizontally in a plane intersecting the axis of the drive shaft 44, and to this end the upper portion of the main frame isA provided with rollers 56 engaging the rear side of the rack 53. The rod 54, as shown in Fig. 8, carries on its center portion a piston 58 slidably mounted in a cylinder 59 `of a double-acting uid operated motor 60 by means of which the carriage is reciprocated.

The rack 53 engages and drives `the barrel pinion 48 'and the latter is made long enough so that the driving engagement between the rack and the pinion is maintained even though the pinion travels up and down with the slide 38. The llength of stroke of the carriage and rack determines the amount of rotation of the drive shaft and hence the extent of rotation of the tools T.

The present invention provides means traveling with the carriage C for regulating the stroke of the carriage and determining at l'what points in its travel its direction was to be reversed.

According,to the present invention. the adinstable controllers 6| may operate any suitable mechanism for causing the carriage to stop at a predetermined point and then reverse its direction oi' travel. However. since, in the embodiment of the invention shown herein, the carriage C is reciprocated by the double-acting fluid motor 68, the controllers 6| are here employed to operate a stopping and reversing valve 84 (see Figs. 4 to 8). l

The reversing valve 64 comprising a housing 66 having a manifold 66 provided with an inlet pipe 61 and two outlet pipes 68 and 69 adapted to be connected to opposite ends of the cylinder 59. Within the housing there is a cylindrical chamber 18 containing a rotary valve 1| having bearings in the housing 65 and in a cover plate 12 for the housing. This rotary valve has a shaft 13 carrying an operating arm 14 which extends into position to be engaged and operated by the controllers 6|.

The rotary valve 1| has two deilnite positions in the cylindrical chamber 16 determined by shock absorbing stops 15 mounted on the cover plate 12. The valve 1| has a central channel 16 communicating with two branches 11 and 18 adapted to alternately communicate with ports 19 and 88 of conduits, preferably formed integral with the housing 65 and leading to opposite ends of the cylinder 59.

In addition, the valve 1| has another pair of channels and ports 8| and 82 cooperating with the outlet orifices 68 and 69 respectively. In one position of the valve, for instance that shown in Fig. 8, the central port 16 being in communication with the feed pipe or inlet 61 transmits uid under pressure through the channel i8 to the port 80, and thus-to the right-hand side of the cylinder 58. At the same time, the channel 8| at the opposite side of the valve is in communication with the outlet pipe 68 and also is in communication with the port 19 leading to the left-hand side of the cylinder, allowing the i'luid therein to escape through the outlet pipe 68. When the valve arm 14 is lrocked to move the valve clockwise 'from the position shown in Fig. 8, the channel 11 is brought into communication with the port 19, the channel 18 is closed by the housing 65, and the channel 82 is connected to the port 88, with the result that fluid under pressure passes through the port 19.

and into the left-hand side of the cylinder and the fluid in the right-hand side escapes through the port and channel 82 to the outlet pipe 69, causing the piston 58 and rod 59 to be stopped and then moved to the right.

In order that the carriage C may be stopped and reversed quickly at exactly the right point in its travel, the valve arm 14 is operated, according to the present invention, with a snap action. carries a plunger 83 in position to engage a sleeve 84 on the end of the arm 14 and tend to operate it. However, in each of its operating positions, the arm 1d is locked against y movement by a locking pin 85 (see Figs. 4, 5 and 6) slidably mounted in the sleeve 84 and springurged to engage a locking piece 86 secured to plunger 83 is being energized, a releasing finger For this purpose, each controller 6| I8 carried by the controller 8| approaches a knob 89 on the locking pin Il. At the proper time, the releasing ringer begins to withdraw the locking pin 85 from the locking piece` 89, and the controller 8| is set so that at just the right moment the pin 85 will be completely withdrawn and the valve arm 14 will be allowed to move undex the influence of the plunger 88 to the other position, the right, as shown in Figs. 5 and 6, with a snap action. The shock of this rapid movement of the arm 14 is absorbed by the shock-absorbing stops 15, and the locking pin 86 engages the other side of the locking piece 86 to hold the valve arm 14 in that position.

It-is\o ntemplated by this invention that one of the controllers 6| may be fixed and incapable of. adjustment, for the adjustment of a single controller will lengtheny or shorten the stroke of the carriage C. However, to permit the points in the travel of the carriage at which reversing takes place and at which the wear of the rack is maximum to be varied, it is preferable that both controllers 6| be made adjustable relative to each other and to the carriage C.

Tool and work feeding According to the'present invention, the carriage C also controls the feeding movements of the tools. For this`purpose, the post 49 at thel upper end of the slide 38 is provided with a collar 98 having a roller 90 in position to be engaged by cams mounted on and traveling with the carriage C.

In the form of the invention herein disclosed, there are two cams 92 and 93, and these are carried by the controllers 6|. The cam 93 is on the right-hand controller 6| and has a sharp rise which causes or permits rapid movement oi the slide 38. 'Ihe cam 93 has a pair of slots 94 through which extend screws 95. used to secure the cam 93 to the controller 6|. These slots 94 extend parallel to the direction of travel of the carriage and permit the cam 93 to be adjusted longitudinally of the carriage independently of the controller, so that the point at which movement of the slide 38 begins and ends may be varied. This cam 93 is intended to control the movements of the carriage during tapping operations.

The cam 92, in the form of the invention herein disclosed, forms a continuation of the cam 93 and is hinged to -it at 96 and has its other end provided with a vertical slot 91 through which passes a screw 98, (see Fig. 5) by means of which this end of the cam is fastened t0 the left-hand controller 6|. The vertical slot 91 permits vertical adjustment of the end of the cam 92 and this movement may be regulated by an adjusting screw 99 carried by the left-hand controller 6|. 'I'he cam 92 is intended to control movements of the slide 38 during the drilling operation and is designed to regulate the extent of downward movement of the slide very accurately, so that a. closed-bottom hole in a workpiece may be tapped just to the proper depth, and so that this may be done without resetting the position of the tool in the holder or worktable.

It is within the scope of this invention to have the cams 92 and 93 actually move the slide i l38 both upwardly and downwardly. However,

regardess of the speed at which the slide 38 descends, 'the present invention provides the slide 38 with springs |00 normally tending to pull them down. Thus, when the carriage C moves from left to right, the slide 38 is allowed to descend under the influence of the springs |00 and at a rate depending upon the inclination of the cams 92 and 93. On the return stroke of the carriage, however, that is, when the carriage moves from right to left, the cams 92 and 93 engage the roller 9|, positively lifting the slide 38 against the tension of the springs |00.

For many purposes, it is suilicent to use the cam 93 alone, and in such cases the cam is carried solely by, and is adjustable as a unit with, the right-hand controller 6|. Of course, it should be understood that the cams 92 and 93 may be given any suitable or desirable shape, depending upon the way that the tools are to be fed to the work, and, since they are removably carried by the controller or the controllers, a separate cam can be made for each job to be done on the machine.

vAs shown in Figs. 2 and 3, the load on the slide 39 and parts mounted thereon is not borne directly by the rod 52 on which the controller 8| is mounted. Instead, the controller is provided with a rail |0| resting on a roller |02 carried on an arm |03 on the main frame and located directly under the roller 9| on the slide frame 38. Hence, the weight of the frame .38 1s transmitted through the cam 93, controller 8| and rail |0| to the roller |02 and the main frame.

It should be noted that in setting up themachine, the mechanic, after locating the spindle brackets 35 in desired positions, securing them to the slide 38, and connecting up the intermecuate gearing, may, while still standing in front of the machine, regulate the extent of feed of the tool slide 38 by merely reaching up and adjusting the position of the cam 93 on the righthand controller 6|. The point in the cycle of operations at which the slide 38 begins to movev may be regulated by loosening theclamp 62-63 of the right-hand controller 6| and adjusting it longitudinally along the rod 52. At the same time, if any adjustment of the position of the worktable 25 is desired, this may bel accomplished by reaching down and turning the handwheel 24. The point at which the drive is to be reversed at the end of the downward movement of the table 38 may be fixed and determined by loosening the clamp 62-63 on the left-hand controller 6| and adjusting it along the rod 52 to the desired position. If it is desired to raise the lower limit of movement of the tool slide 38, the mechanic may merely reach up and adjust the end of the cam 92 by means of the adjusting screw 99.

Thus, according to the present invention, itis unnecessary for the mechanic setting up the machine to go around to the back or to the side of the machine to make adjustments changing the extent or timing of the feeding operations.

Indexing According to the present invention, the means for moving the worktable 25 step-by-step is also hydraulically operated. This turntable 25 is provided with a shaft |04 having an index wheel |05 secured thereto.

Also mounted on the shaft |04 is an arm |06 provided with a pawl |01, the end of which env gages teeth |08 in the index wheel. The pawl is held in position to enter between the teeth |08 by a spring |09 and the pawl arm is returned to normal position after being operated by a spring ||0.

For the purpose of operating the pawl arm and thus moving the turntable 25 step-by-step, a cylinder mounted adjacent the index wheel |05 is provided with a piston ||2 and a piston rod ||3, the end of which extends out through the cylinder and'is in position to engage the end o1' the pawl arm |06. Instead of directly engaging the arm |06, the piston rod ||3 engages a screw ||4 adjustably mounted on the end of the arm |06.

The indexing wheel |05 is locked in its p0- sitions of rest by a dog |5 which enters between the teeth |08. This dog is on the end of a piston rod ||6 carrying a piston located in a cylinder H8. As shown in the accompanying drawings, the cylinders and ||9 are connected together as a unitary structure and are operated' coordinately by hydraulic pressure.

For this purpose, the cylinders and ||8 are connected together by a. pipe or conduit ||9 leading from the lower part of the former to the upper part of the latter as viewed in Fig. 19, and another pipe or conduit |20 leading from the upper part of the cylinder to the lower part of the cylinder ||8. This same part of the cylinder I|8 is connected by pipes |2||22 to an indexing control valve |23, while the conduit or pipe ||9 is connected by pipes |24| 25 to the other side of the indexing control valve |23.

Between the pipes |2| and |22, and |24 and |25 are extensible connections |22a and |25a respectively, to permit the vertical movement of the worksupport 2| the dial 25 and the indexing lmechanism relative to the pipes |22 and |25 leading to the control valve |23 which is mounted on the-stationary part or main frame of the machine.

In the broader aspects of this invention, any

suitable control valve may be employed which will cause the fluid under pressure flowing through thepipes |22 and |25 to be reversed in its direction of iiow. As diagrammatically illustrated in Fig. 19, the movement of the fluid under pressure is indicated by the arrows, and leaving the valve |23 flows down from the pipes |22 and |2| into the lower part of the cylinder I I8 where it forces the piston and rod ||6 outwardly causing the dog ||5 to lock the index wheel |05 against rotation. The uid then passes through the lower end of the' cylinder ||8 into the pipe or conduit |20 and into the upper end of the cylinder where it has forced the piston ||2 and piston rod ||3 inwardly of the cylinder allowing the spring ||0 to re tract the pawl arm |06.

In so moving the parts, the uid on the upper side of the piston ||1 and on the lower side of the piston ||2 escapes through the pipe ||9 and pipes |24 and |25 back to the control valve |23.

When the direction of ow is reversed, however, the iluid will flow from the valve |23 through the pipes |25-|24 into the pipe or conduit ||9 and from this into the upper part of the cylinder ||8 and the lower part of the cylinder with the result' that the piston ||1 will move inwardly and withdraw the locking dog ||5 from the index wheel, and the piston ||2 will move outwardly driving the pawl arm to advance the index wheel |05 and dial 25. At

the same time, the fluid on the other side of the two pistons, namely, the top of piston ||2 and the bottom of piston ||1, will be permitted to escape through the pipes |20, |2| and |22.

When the valve |23 is reversed at the end of the indexing operation in a manner hereinafter described, it is desired that the locking dog ||5 engage the index wheel |05 before the pawl arm |03 begins to return so that it will not drag the indexvwheel |05 back with it. In order to insure this, the pipe or conduit |20 is interrupted at some portion between the cylinders and H0, and at the interruption is provided with a pressure regulating valve |26, .shown in detail in Figs. 17 and 18.

In the specic embodiment of the invention herein disclosed. PSM of the conduit |20 is formed by a channel |21 in the piece making up the cylinder and the regulating valve |26 is located to interrupt this channel. The valve comprises a movable or plunger portion |28 slid- Aing in a cylinder |29 and normally urged upwardly by a spring |30, the lower end of which engages an adjustable cap or screw |3|. The upper end of the plunger |20 has a knife edge |32 engaging a seat |33 and bleed openings |34 permit the flow of some fluid past this valve at all times. The spring is set, however, so

, that the full amount of iluid. will not pass through the channel |21 until sufllcient presinto the cylinder within which the plunger moves may escape upwardly and outwardly through the holes |35. I

This coordination of the index wheel lock and feed arm may, of course, be done mechanically, but when accomplished hydraulically, as herein disclosed, the use of much complicated mechanism is avoided and the functions are Vperformed by the simple pressure regulating valve |26. As stated above, the indexing control valve |23' may be of any suitable type and construction, and maybe operated in any suitable way.

However, according to the present invention,

the control valve is operated by means carried by the right-hand controller 5|. For this purpose, the controller 6| is provided withl an extension |36 having an arm |31 carrying a cam |38 (see Figs. 3 and 19), vand the control valve |23 is mounted on the main frame along side the cylinder 59 to be in position to be operated by the cam |33 when the carriage C reaches the end of its movement toward the left.

As shown in Figs. 9 to 13, the valve |23 has a housing '|39 provided with a top plate |40 and a bottom plate |4|, and these parts form between them cylinder chambers |42 and |43 in which are mounted pistons |44 and |45. The cylinders |44 and |45 are connected together for movement in opposite directions simultaneously by a lever |46, whose end engages in slots |41 in the pistons |44 and |45. The piston |45 is normally urged downwardly by a spring |48, the upper end of which is located in a housing |48a.

Thus, the pistons are biased to normally occupy the position shown in Fig. 9. The lever |46` is mounted on a shaft |49 which extends out through the housing and has an arm |50 provided with a roller |5I.

This roller |5| normally lies in a position to be engaged by the cam |38 shown in dot-anddash lines in Fig. 9, and when engaged by the cam is rocked counterclockwise with the result that the piston |44 is depressed and the piston rises against the tension of the spring |48. When the cam |38 recedes from the roller |5I, the spring |48 returns the parts to the position shown inFig. 9.

The pipes leading to the control valve are arranged in manifold form in a manifold |52, and the conduits in this manifold are given the same reference numerals as the pipes in the diagrammatic illustration of the system shown in Fig. 19. Accordingly, the conduit or channel |25 leads to the cylinder |42, while the conduit or channel |22 leads to the cylinder |43. Between these two channels is another channel |53 which leads from the control valve |23 to the pipe |8 and pump I6.

Fluid under pressure ilows through the channel |53 and may then ilow to the right or to the left through an auxiliary channel |54 to the piston |44 or |45. With the parts in the position shown in Figs. 9 to 13 and 19, fluid under pressure flows from the channel |54 into an annular groove |55 in the piston |45, and since this annular groove is in communication with the channel |22 at this time, fluid flows in the direction of the arrows shown in Fig. 19. At the same time, a cut-away portion or port |56 in the piston |44, the lower end of which is hollow, is located opposite the opening of the channel |25, and the fluid rising in the pipe |25, as shown in Fig. 19, ilows into the hollow end of the piston |44 and then downwardly into a horizontal channel |51 located below the piston. This channel |51 connects with a channel and pipe |58 leading to the reservoir l2.

When the cam |38 engages the roller |5| and rocks the arm and shaft |49 and reverses the positions of the pistons from that shown in Fig. 9, the channel |22 is connectedvto the outlet channel |51 by the hollow cut-out lower portion of the piston |45, and the channel |54 is connected with the channel |25 by the annular groove in the piston |44, with the result that the direction of flow of the fluid is reversed. This causes the dog ||5 operated by the piston ||1 to disengage the index wheel |05 after which the feed arm |06 isreturned by the piston H2.

In order to cause the indexing and locking devices to operate before suilicient pressure is applied to the driving piston 58 to cause movement thereof, a pressure regulating valve |59 is interposed between the main feed pipe |8 and 'the pipe 61 leading to the valve 64. This valve |59 is illustrated in detail in Fig. 21. It cornprises a housing |60 in which is located a valve |6| having a bleed port |62 allowing some fluid to escape past the valve at all times. The valve is normally pressed down on its seat by a spring |63 and the upper end of the spring is engaged by a screw cap |64 threaded in the housing |60. By rotating the screw cap |64, the tension of the spring may be increased or decreased, thereby determining at what pressure the valve |0| will open and permit passage of the fluid to the pipe 16. A cap |65 threaded 0n the cap |64 serves to conceal the cap and Fig.`19 and shown in detail in Fig'. 22.

acts as a lock nut to prevent its casual movement.

A safety valve |66, constructed substantially the same as the valve |59, is connected to the pipe 16 and has an outlet pipe |61 leading back to the reservoir I2. Thus, whenv the fluid in the system exceeds the predetermined pressure, the surplus escapes through the valve |66 and outlet pipe |61.

When the carriage C is at the end of its movement toward the right and while the valve 64 is shifting from one position to another, there is a time when fluid under pressure is applied to both ends of the cylinder and both sides of the piston, with the result that the piston is stopped with a hammer blow producing shocks and vibrations which are undesirable. To avoid this diiliculty, the present invention provides a relief valve |68 shown in This relief valve has a housing |69 provided with a piston-like valve I 10 normally urged downwardly by a spring |1|, the upper end of which engages a perforated wall |12 in the housing. The end of the valve |10 extends through a gland |13 in position to be operated by a cam |14 carried by the left-hand controller 6|. The valve |10 has a portion |15 normally closing a port |16 in the housing connected to a pipe or conduit |11 opening into the pipe 19, leading to the left-hand side of the cylinder 59. The upper end of the valve housing |69 is provided with an outlet |18 connected a pipe |19 opening into a pipe |80 joined to the outlet pipes 68 and 69 which is controlled by the valve 64.

When the carriage reaches its extreme righthand position, the cam |14 lifts the valve |10 so that the fluid under pressure in the'pipe |11. may pass into the valve through an annular recess |8| therein. Fluid may then flow upwardly through small apertures |82 in the valve and through the perforated wall |12. Here, however, it is stopped by a pressure regulating valve |83 backed by a spring |84 having an adjustable cap |85 and a cover cap |86. The fluid cannot escape past the pressure regulating valve I 83 except when it is under abnormal pressure due to the fact that the fluid is being applied to both sides of the piston 58. When this abnormal pressure is such that it would cause the piston 58 to be stopped abruptly, the fluid may escape past the valve |83 into the return pipe |80.

Of course, the relief valve |68 may be provided, if desired, for both ends of the pistons travel, but it is not necessary, in the embodiment of the invention herein disclosed, because at the time that the piston 58 and carriage C reach the end -of their travel toward the left, the indexing mechanism begins to operate, and this so reduces the pressure of the fluid as to prevent the hammer blow above referred to.

Variations and modifications may be made Within thescope of this invention and portions of the improvements may be used Without others. y

Having thus described the invention, what is claimed as new and for which it is desired to obtain Letters Patent, is:-

1. In a drilling and tapping machine, the combination of a work-holder; a tool-holder; a tool driving shaft; a pinion on said shaft; a. carriage mounted to reciprocate in a plane intersecting the axis of said shaft; a rack on said carriage engaging and driving said pinion; Ie-

' the versible power means connected to said carriage to reciprocate the same; and means, including means traveling with said carriage, for automatically reversing the action of the power means at the ends ofv travel of the carriage.

, 2. In a drilling and tapping machine, the combination of a work-holder; a tool-holder; a tool driving shaft; a lpinion on said shaft; a carriage mounted to reciprocate in a plane intersecting the axis of said shaft; a rack on= said carriage engaging and driving said pinion; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with said carriage, for automatically stopping and reversing the action of the power means at the ends of travel of the carriage, said last-named means comprising adjustable devices, one mounted at each sidev of the carriage and each adjustable along the carriage to vary the points in the travel of the. latter at which its movement isstopped and caused to reverse.

3. In a drilling and tapping machine, the combination of a work-holder; a tool-holder; a tool driving shaft; a pinion on said shaft; a carriage mounted to reciprocate in a plane intersecting the axis of said shaft; a rack on said carriage engaging and driving said pinion; means for producing relative feeding move-v ments of the work-holder and tool-holder toward and from each other, said means including a reciprocating slide on which one of said holders is mounted, and a cam traveling with said carriage and engaging said slide to control feeding movements thereof; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with said carriage, for automatically reversing the action of the power means at the ends of travel of the carriage.

4.1m a.' drilling and tapping' machine, the combination of a work-holder; a tool-holder; a tool driving shaft; a pinion on said shaft; a carriage mounted to reciprocate in a `plane intersecting the axis of said shaft; a rack on said carriage engaging and driving said pinion;

' means for producing relative feeding movements of the work-holder and tool-holder .toward and from each other, said means including a reciprocating slide on which one of said holders is mounted, and a cam traveling with said carriage and engaging said slide to control the feeding movements thereof, said cam being adjustable along the carriage to vary the relative movements of the tool-holder and the work-holder in relation to the traveling movements of the carriage; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with said carriage, for automatically stopping and reversing the action of the power means at the ends of travel of the carriage, said last-named means comprising adjustable devices, one mounted at each side of the carriage and each adjustable along the carriage to vary the points in the travel of the latter at which its movement is stopped and caused to reverse.

5. In a drilling and tapping machine, the combinationof a frame; a tool-holder; a workholder; means for producing relative feeding movements of the tool-holder and work-holder toward and from each other including a slide on which one of said holders is mounted; a carriage mounted to travel at right angles to the c iiretion` of movement of the slide; a cam on the carriage engaging the slide to control the feeding movements of the latter; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with the carriage, for controlling the direction and extent of operation of the carriage.

6. In a drilling and tapping machine, the combination of a frame; a tool-holder; a workholder; means for producing relative feeding movements of the tool-holder and work-holder toward and from each other including a slide on which one of said holders is mounted; a carriage mounted to travel at right angles to the direction of movement of the slide; a cam on the carriage engaging the slide to control the feeding movements of the latter; a double acting fluid operated motor for reciprocating said carriage; and means, including a reversing valve and operating means therefor, in part mounted on the carriage and in part mounted on the frame, for controlling the direction and extent of operation of the carriage.

7. In a drilling and tapping machine, the combination of a tool-holder; a Work-holder; means for resiliently feeding one of said holders toward the other to do Work; means for rotating the tool-holder; and a fluid operated element for simultaneously operating the rotating means and permitting said resilient feeding means to operate.

8. In a drilling and tapping machine, the combination of a frame; a tool-holder; a workholder; means for rotating said tool-holder; means for indexing the workholder to bring pieces of work successively into position to be operated upon by a tool in the tool-holder; and fluid operated means for supplying power to and rotating said rotating means and operating said indexing 'means alternately and in coordination.

9. In a drilling and tapping machine, the combination of a tool-holder; a work-holder; means for feeding one of said holders toward and from the other independently of the rotation of the tool holder; means for rotating said tool-holder; means for indexing the work-holder to bring pieces of work successively into position to be operated upon by a tool in the tool-holder; a fluid motor for supplying power to and operating said feeding means and rotating means simultaneously and in coordination; a separate fiuid motor for operating the indexing means alternately with said feeding and rotating means; and means for controlling said motors for coordinate operation.

10. In a drilling and tapping machine, a reciprocating power transmitting carriage; a doubleacting fluid motor operating said carriage; a source of fluid pressure; a reversing valve connecting the source of fluid pressure to said fluid motor; an operating arm on said valve; means for locking the arm in right and left hand positions; yielding means traveling with the carriage and becoming operative'near the end of travel of the carriage to tend to rock said arm; and means traveling with the carriage to release the lock suddenly at the end of travel of the carriage and permit said yielding meansl to rock said arm and reverse the direction of drive of the fluid motor and carriage.

11. In a drilling and tapping machine, the combination of a frame; a tool-holder; a workholder; means for producing relative feeding movements of the tool-holder and work-holder toward and from each other including a slide on which one of said holders is mounted; a carriage mounted to travel at right angles lto the direction of movement of the slide: a cam on the carriage engaging the slide to control the feeding movements of the latter; a double acting `fluid operated motor for reciprocating said carriage; means, including a reversing valve and operating means therefonin part mounted on the carriage and in part mounted on the frame, for controlling the direction and extent of operation of the carriage; and means for relieving the pressure of the fluid onone side of the motor during the reversing operation thereof.

12. In a drilling and tapping machine, the combination of a frame; a tool-holder; a workholder; means for producing relative feeding movements of the tool-holder and work-holder toward and from each other including a slide on whichone of said holders is mounted; a carriage mounted to travel at right angles to the direction of movement of the slide; a cam on the carriage engaging the slide to control the feeding movements of the latter; a, double acting fluid operated motor for reciprocating said carriage; means, including a reversing valve and operating means therefor, in part mounted on the carriage and in part mounted on the frame, for controlling the direction and extent of operation oi the carriage; and means for relieving the pressure on one side of the motor during the operation of the reversing valve, said means including a. valve operated by the reciprocating carriage and connected to the fluid operated motor to bypass the fluid at one side of the piston when under excess pressure incidental to the operation of the reversing valve.

13. The invention as defined in claim 5, in which the cam for controlling the feeding movements of the slide is adjustable longitudinally relative to the carriage and to the controlling means thereon.

14. 'I'he invention as defined in claim 5, in which the cam for controlling the feeding movements of the carriage is vertically adjustable at one end to vary the rate of feeding movements of the slide relative to the traveling movements of the carriage.

15. The invention as defined in claim 5, in which the cam for controlling the feeding movements of the slide is made of two adjustably connected parts, one part determining the upper limits of movement of the slide andthe other part determining the lower limits of movement of the slide.

16. The invention as defined in claim 5, in which the cam for controlling the feeding movements of the slide is made of two adjustably connected parts, one part determining the upper limits of movement of the slide and the other part determining the lower limits of movement of the slide, the last-named part being vertically adjustable relative to the carriage to vary the lower limits of movement of the slide.

17. 'Ihe invention as defined in claim 5, in which the cam for controlling the feeding movements of the slide is made of two adjustably connected parts, one part determining the upper limits of movement of the slide and the other part determining the lower limits of movement of the slide, the last-named part being vertically adjustable relative to the carriage to vary the lower limits of movement of the slide, and the part which controls the upper limits of movement of the slide being longitudinally adjustable relative to the carriage to vary the point in the operations of the machine at which the slide reaches its upper limitsof movement.

18. In. a tapping machine, the combination of a Work-hielder; a tool-holder; a tool driving shaft; a pinion on said shaft; a carriage mounted to reciprocate in a plane intersecting the' axis of said shaft; a racl; on said carriage engaging and driving said pinion; reversible power means connected to said carriage to reciprocate the same; and means including means traveling with lsaid carriage, for automatically reversing the action of the power means at the ends of travel of the carriage.

19. In a tapping machine, the 'combination of a work-holder; a tool-holder; a tool driving shaft; a pinion on said shaft; a carriage mounted to reciprocate in a plane intersecting the axis of said shaft; a rack on said carriage engaging and driving said pinion; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with said carriage, for automatically stopping and reversing the action of the power means at the ends of travel of the carriage, said lastnamed means comprising adjustable devices, one mounted at each side of the carriage and each adjustable along the carriage to vary the points in the travel of the latter at which its movement is stopped and caused to reverse.

20. In a tapping machine, the combination of a frame; a tool-holder; a work-holder; means for producing relative feeding; movements of the tool-holder and work-holder toward! and from each other including a slide on which one of said holders is mounted; a carriage mounted to travel at right angles to the direction of movement of the slide; a cam on the carriage engaging the slide to control the feeding movements of the latter; reversible power means connected to said carriage to reciprocate the same; and means, including means traveling with the carriage, for controlling the direction and extent of operation of the carriage.

21. In a tapping machine, the combination of a frame; a tool-holder; a work-holder; means forvrotating said tool-holder; means for indexing the work-holder to bring pieces of work successively into position to be operated upon by a tool in the tool-holder; and iiuid operated means for supplying power to and rotating said rotating means and operating said indexing means alternately and in coordination.

22. In a tapping machine, the combination of a frame; a tool-holder; a work-holder; means for producing relative feeding movements of the tool-holder and work-holder toward and from each other including a slide on which one of said holders is mounted; a carriage mounted to travel l at right angles to the direction of movement of the slide; a cam on the carriage engaging the slide to control the feeding movements of the latter; a double acting fluid operated motor for reciprocating said carriage; means, including a reversing valve and operating means therefor, in. part mounted on the carriage and in part mounted on the frame, for controlling the direction and extent of operation of the carriage; and means for relieving the pressure of the fluid on one side of the motor during the reversing operation thereof.

ERIC J. STAHLHAMMER.

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