US2068529A

US2068529A - Grinding machine

Info

Publication number: US2068529A
Application number: US601485A
Authority: US
Inventors: William G Baldenhofer
Original assignee: Thompson Grinder Co
Current assignee: Thompson Grinder Co
Priority date: 1932-03-28
Filing date: 1932-03-28
Publication date: 1937-01-19
Anticipated expiration: 1954-01-19

Description

Jan. 19, 1937.

W. G. BALDENHOFER GRINDING MACHINE Filed March 28, 1952 5 Sheets-Sheet l INVENTOR ATTO RNEYS n- 1937- w. G. BALDENHOFER 2,058,529

GRINDING MACHINE Filed March 28, 1932 5 Sheets-Sheet 2 ammw mun /Q A;

ATTORNEYS 1937- w. e. BALDENHOFER 2,068,529

GRINDING MACHINE Filed March 28, 1932 5 Sheets$heet 3 ATTO RN EY 1937- r w. G. BALDENHOFER ,0

GRINDING MACHINE Filed March 28, 1952 5 Sheets-Sheet 4 J/39 i I :01 ms T517 INVENTOR ATTORNEYS Jan. 19, 1937. w G BALDENHOFER 2,068,529

' GRINDING MACHINE in BY w W ATTORNEYS Patented Jan. 19, 1937 UNITED STATES PATENT OFFICE GRINDING MACHINE Application March 28, 1932, Serial No. 601,485

25 Claims.

of a cylinder, piston andpiston rod. The toolhead is usually advanced or retracted in successive intermittent movements of varying extent by a similar motor, the intermittent movements be-' ing timed to occur at the ends of the working strokes of the work-holder. The grinding operation is performed on the work supported on the work-holder by peripheral contact of a rotatable grinding wheel, which is mounted on the outer end of a wheel spindle supported in a horizontally disposed tool-head in such manner that the longitudinal axis of the spindle is located at rightangles to the direction of travel of the workholder, whereby a flat surface is produced on the work by feeding the wheel across the work in successively intermittent movements.

The machine described in the present specification follows a customary practice in providing reversing mechanism which .is operated by stopdogs adjustably secured to the work-holder, this 30 mechanism governing the reversals of the workholder, and also by the provision whereby the fluid under pressure is supplied to the separate fluid motors from a common source.

In the present machine the intermittent feed 3 imparted to the tool-holder is obtained by supplying successive predetermined quantities of fluid to the same end of the cylinder of the toolholder motor, and both the tool-holder motor and the work-holder motor are supplied from the same source of fluid under pressure. One of the disadvantages of such an arrangement has been that due to varying fluid pressures when the speed of the work-holder is changed, successive charges of fluid of a different quantity will be admitted to the tool-holder moto'r resulting in a change in theextent of the intermittent feeds of the tool-holder. If the speed of the work-holder motor is decreased, the successive intermittent movements of the tool-holder become greater, and 50 if the speed of the work-holder motor is increased the extent of the successive feeds of the toolholder is reduced. As a consequence of this, unless provision is made otherwise for preventing it, the quantity of the successive fluid charges admitted to the tool-holder motor will obviously vary at different speeds of the work-holder resulting in a variation in the feed of the toolholder.

One of the objects of this invention is to overcome this objection by providing that uniform 5 successive charges of fluid will be admitted to the tool-holder motor regardless of the speed of the work-holder.

Another object of the invention is the provision of means incorporated in a unitary hydraulic 10 valve control mechanism, whereby a smoothly operating machine is afforded. One of the advantages of fluid motor drive is that infinite gradation of work-holder speeds is readily obtainable. Ordinarily, however, the operation is ham- 15 pered by vibration due to shock at work-holder reversals. The present invention provides a cushioning efiect whereby allshock is eliminated.

Another object is the provision of improved means for controlling the extent of each inter- 2o mittent movement of the tool-head, which means may also be employed to alter the direction of movement of the tool-holder.

Another object is to provide means acting in combination with the devices just mentioned which control the tool-head movements whereby a continuous movement may be given the toolhead in either direction, the direction being under the control of the intermittent control means.

Another object is to provide that the tool-head is maintained in position during the intervals between times of movement; that is,- the tool-head is substantially in a "locked position.

In the accompanying drawings:

Fig. 1 is a front elevation partly broken away' and shown in section showing a typical grinding machine in a conventional manner having the improvements incorporated therein.

Fig. 2 is a fragmentary vertical section on the line 22 of Fig. 1.

Fig. 3 is an enlarged view partly in front elevation and partly in vertical section of some of the parts shown in Fig. 1.

Fig. 4 is an enlarged view partly in end elevation and partly in vertical section of the parts seen in Fig. 3.

Fig. 5 is an enlarged sectional detail view, the section being taken on the line 5-5 of Fig. 3.

Fig. 6 is an enlarged fragmentary section on the line 6-6 of Fig. 1.

Fig. 7 is an enlarged view of the valve control mechanism partly in end elevation and partly in vertical section.

Fig. 8 is a slightly enlarged fragmentary section on the line 88 of Fig. 3.

line

the line |z |2 of Fig. 3.

Fig. 13 is an enlarged fragmentary horizontal section on the line l3-l3 of Fig. 3.

Fig. 14 is an enlarged fragmentary longitudinal section on the line I4-l4 of Fig. 4.

Fig. 15 is an enlarged perspective view partly in section of a detail of the hydraulic valve control mechanism, the portion shown in vertical section being taken on the line l5-I5 of Fig. 3.

Fig. 16 is an enlarged fragmentary section on the line lG-IG of Fig. 3.

Fig. 17 is a sectional view in perspective showing portions of the valve control mechanism for the tool-head fluid motor.

Fig. 18 is an enlarged fragmentary longitudinal section on the line Ill-I8 of Fig. 4.

Fig. 19 is an enlarged fragmentary longitudinal section on the line i9-i9'of Fig. 4.

Fig. 20 is an enlarged fragmentary elevation partly in longitudinal section of details of the valve control mechanism, for governing the toolhead intermittent movements.

Fig. 21 is a fragmentary section, the section being taken at the same point as the sectional portion of the view shown in Fig. 20, but with the working parts in a different position.

Fig. 22 is a vertical section on the line 22-22 of Fig. 20.

Fig. 23 is a partial front elevation similar to Fig. 20, with parts in a different position.

Fig. 24 is an enlarged fragmentary horizontal section on the line 24-24 of Fig. 22.

Referring to the drawings the base of the grinding machine is indicated at I. On this is mounted for reciprocatory motion on V-ways 2 and flat-ways 3 a work-holder 4 to which the work may be attached in any of the usual methods.

Reciprocatory motion is imparted to the workholder by means of fluid pressure acting in a fluid motor. This motor comprises a cylinder 5, one end of which is secured to the inside upper portion of the base I (Fig. 1) a piston 6 and a piston rod 1, the outer end of which is secured to a downwardly-extending arm 8 attached to an extension of the work-holder 4 (Fig. 1). Fluid under pressure is admitted alternately to each end of the cylinder 5, there being a port 9 at the right, and a port I0 at the left of the cylinder 5 (Fig. 1). Communicating with these ports are conduits II and I2, respectively, which lead toports in the body portion l3 of the unitary structure housing the hydraulic valve control mechanism.

The work-holder is reversed at the ends of a desired stroke by the reciprocatory movements of a master piston valve to which motion is imparted by means of fluid pressure under the control of a piston pilot valve, which in turn receives its motion from the work-holder itself. Due to the small size of the pilot valve and although the pilot valve operates in fluid pressure equal to those pressures which the master valve controls, the movements of the work-holder are not affected.

The pilot valve is moved by contact with stopdogs I4 and i5, (Figs. 1 and 6) adjustably positioned on the work-holder with pawls I6 and I1 pivotally mounted on the forward and rear side,

of a reversing lever I3, which is pivotally mounted on the forward side of the base I at I9. At thelower end of the reversing lever I9 is pivotally mounted one end of a connector bar 20 which at its other end is pivotally secured to the upper end of a short crank-arm 2| (Figs. 1, 4 and 7) integrally attached to a horizontally disposed hollow shaft 22 rotatably .supported on a stud 29 and having at its other end an upwardly extending fork 11 which straddles a notch 13 at the approximate center of the pilot valve 23, (Figs. 3 and 12). The pilot valve 23 is a portion of the hydraulic valve control mechanism which will be described later in the specifications.

The abrasive wheel 24 (Figs. 1 and 2) is mounted on the end of the horizontal shaft or spindle 25 supported in

bearings

29 and 21 of the toolhead slide 28. The tool-head slide is supported in angularly disposed ways 29 machined in the lower part of a projecting portion 30 of a vertical slide 3|. The slide 3| is gibbed by gibs 32 to the vertically disposed ways 33' of a column 33 attached to the base I, and by means (not shown) may be elevated or lowered so that the position of the wheel 24 with respect to the work on the workholder 4 may be altered. The tool-head slide 28 is actuated by a fluid motor similar to the motor previously described in connection with the operation of the work-holder. The tool-head fluid motor comprises a cylinder 34, one end of which is secured to the inner surface of an upper wall 35 of the vertical slide 3|. A piston 36 on the inner end of a piston rod 31 operates within the cylinder 34, while the outer end of the piston rod 31 is connected to a vertically extending arm 39 secured to the upper portion of the slide 28. Fluid under pressure is admitted in successive charges to either end of the cylinder 34 whereby the slide is moved step-by-step in either direction in a horizontal plane at right angles to the direction of travel of the work-holder 4. Fluid is conveyed to the cylinder 34 by means of conduits 39 and 40 (Figs. 1 and 2), the fluid being admitted to the cylinder through ports 4| and 42 respectively, in the forward and rear ends of the cylinder heads of the cylinder 34 under the control of the hydraulic valve control mechanism in a manner. later to be described.

The spindle is rotated by means of an electric motor shown conventionally in Fig. 2, 44 representing the field ring and 45 representing the rotor of this motor, the rotor being secured directly'to the spindle 25.

The fluid under pressure is supplied to the hydraulic valve control mechanism by means of a pump 46 driven by a small electric motor 41. A conduit 48 connected to the suction side of the pump 46 conveys fluid from a receptacle 49, the suction end of the conduit 48 being submerged below the fluid level of the fluid which is stored in the receptacle. To the discharge side of the pump is connected a pipe 50 which leads to the valve control mechanism l3; interposed in this pipe is a pressure regulating and relief device shown conventionally at 5| whereby the pressure is regulated and excess fluid is returned to the storage tank 49 through the open-ended pipe 52.

Valve control mechanism The manner in which the work-holder 4 is started, stopped, automatically reversed at the ends of the desired stroke follows a customary practice. The supply of fluid to either end of the work-holder fluid motor is under the direct control of a master piston valve which itself is under the control 01' the previously mentioned pilot valve 23. It is preferable to interpose a stopping, starting and throttling valve between the source of supply 01' the fluid and the work-holder fluid motor whereby the movements and rate or speed of the work-holder may be controlled independently of the movement of the pilot valve. The advantages of this construction are that the operator may stop the work-holder at any point desired and .resumeoperations in either direction at the same or changed rate of speed. However, in the present invention, the pilot valve 29 also controls the successive intermittent movements of the toolhead whereby whenthe work-holder movement continued motion or the tool-head at this time I might be a source of danger to the operator. The master valve is given a reciprocatory movement so as to supply fluid to one end and allow the exhaust of the fluid from the other end of the workholder fluid motor.

Referring to Fig. 3, the master valve is indicated in general at 53. It consists of a series of pistons integrally, attached to a cylindrical rod and is closely fitted in a comparatively long bore 51 in the lower portion of the hydraulic valve control body 13. Fluid is fed to the central portion of the master valve bore 51 through a port 55, thence downwardly through a large main port 56 (Figs. 3, 4, l3, l5, and 17) which leads directly into the bore 51.

In order to stop and start the work-holder and govern the rate of speed thereof, a stop and throttle valve 58 of the plug type is horizontally positioned in the valve body l3, intersecting the port 56, whereby the fluid may be entirely cut off and prevented from reaching the master valve 53. A lever 94 is attached to the cylindrical extension 95 of the throttle valve 58 by which this valve is actuated.

Referring to Fig. the plug type valve 58 is shown in perspective and in this view the port 56 is completely closed by the solid portion 58' of the valve. A suitable notch 59 is machinediin one side of the valve body in alignment with the port 56 so that when the throttle valve 58 is rotated, in the present case through a one-quarter turn, the full capacity of the port 56 is presented for a flow of fluid to the master valve bore 51.

The master valve is provided at its central portion with the pistons 60 and 6| (Fig. 3). In this viewthe piston 60 is in position to permit a flow of fluid from the port 56 to the conduit l2 leading to the left-hand end of the work-holder motor cylinder 5 while the piston 6| is preventing a flow into the conduit l 1 leading to the right hand end of theabove mentioned motor with the obvious result that the work-holder will move to the right. As the work-holder moves in this direction, the right end of the cylinder is opened to exhaust by providing that the flow of fluid is reversed through the conduit II and is discharged to the storage tank 49. In Fig. 3, a port 62 will be noticed leading directly from the master valve bore into an exhaust port 63 (Figs. 8, 9 and 15) which port is positioned in parallel relation to the master valve bore 51. Fluid from the exhaust port 63 is eventually returned through the conduit 64 to the tank 49.

The position of the master valve as shown in time in the extreme right end of the master valve bore 51. This pressure acts against the piston 65 of the master valve and therefore, moves the valve to the left end of the bore. The fluid which caused the movement is supplied under the control of the pilot valve in the following manner: Referring to Fig. 13, fluid is conveyed from the main port 56 through a short port 61, a horizontal port 68 and'a port 69 to the pilot valve bore 66; the port 69 being angularly disposed for a reason which will appear later. The fluid enters the pilot valve bore 66 between the

pistons

16 and 1| oi the pilot valve. Two ports lead from this portion of the bore: the function of one of these ports 69' being explained hereafter. The other port 12 in effect leads to the right end of the master valve bore 51, while at the right end of the pilot valve bore, beyond the piston 11 is an exhaust port 8!. The fluid flows'into the downwardly and forwardly positioned port 12, thence into a horizontal port 15, which extends towards the extreme right end of the bore 51, and from theport 15 into the master valve bore 51 through a short vertical port 16 (Figs. 3 and 4).

In order to eliminate shock at reversals, the flow of fluid through theport 12 is throttled, whereby the rate of movement of the master valve is governed. This is accomplished by providing a choke screw (Fig. 4) so positioned that it projects into the port 12, so that when the choke screw 14 is threaded inwardly, the eiiective area of the port 12 is reduced. This choke acts to decrease the movements of the master valve in either of its directions, as when the master valve moves to the right, fluid from the right end of the master valve bore 51 must be displaced and by choking the reverse flow, serves to decrease the valve rate of movement.

work-holder strikes its pawl l6, the resulting pivotal movement of the reversing lever l8 moves the pilot valve to the left and as the pilot valve controls the master valve, the master valve is moved to the right, which movement reverses the work-holder movement. The manner in which the master valve is moved to the right is identical with that already described for the master valve movement to the left. Fluid to the right end of the pilot valve is cut ofi and fluid entering the left end of the bore from the main port 56 through the horizontal port 83 (Figs. 4, '1, 11 and 1'1) and the downwardly extending port 84 (Figs. 7 and 11) is confined between the pistons 85 and 86 (Fig. 13). In Fig. 13, the pilot valve is at its extreme right hand position, this being the result of a previous work-holder reversal. On the movement of the pilot valve to the left, the piston '86, of the pilot valve moves beyond a pair of

port openings

81 and 88 and permits fluid to flow therein, from the port 84. One of these ports 81 corresponds to the port 69' at the right end ofthe pilot valve bore, its purpose appearing later. The other port 88 (Figs. '1 and 13) leads downwardly (Figs. 7 and 9) and fluid flowing therethrough eventually arrives at the extreme left end of the master valve bore through the com municating ports 89 (Figs. 7 and 9), port 98 (Figs. '7, 8, 9 and 10) and port 9| (Figs. 7 and 8). Simultaneously, with the downward flow just described, the fluid at the extreme right end of the master valve bore displaced by the movement of the master valve is flowing to exhaust in reverse flow'through the ports I6, I! and I2 into the pilot valve bore. Since the pilot valve is at this time at its left position, the port 69 is closed and the port 12 is in communication with the exhaust port 8| (Figs. 4 and 13) which leads directly to the exhaust port 63.

Continued movement of the work-holder 4 to the left follows until the dog I4 strikes the pawl II. This restores the pilot valve to the righthand position as seen in Fig. 13, with the results described. This movement also connects the extreme left end of the master valve bore to the exhaust port 63, permitting fluid therefrom to flow in reverse order through the ports 9|, 90, 89 and 88 into the pilot valve bore 66 and thence through the downwardly extending port 93 (Figs. 3, 7 and 13) which leads directly to the exhaust port 63.

The description thus far has dealt with the manner of providing w'ork-holder movements and reversals, together with a description of the throttling, stop and start means, and a description of the means whereby the shocks ordinarily accompanying work-holder reversals are reduced to the point of elimination. The manner of obtaining tool-head movements without the disadvantages noted, is as follows:

Tool-head motor I The motor which operates the tool-head receives a uniform quantity of fluid at each reversal of the work-holder and is supplied with fluid from the same source as the work-holder motor. Reference has heretofore been made to the fact that where both motors are supplied from a single source, changes of speed of the work-holder motor will result in a varying fluid pressure, this variation in pressure being in proportion to the speed of that motor. In order that said varying pressures may not affect the uniform extent of the intermittent movements of the tool-holder motor and hence of the tool-head provision is made for insuring that a uniform quantity of fluid will be admitted to the tool-holder motor regardless of the variations in pressure of the fluid at the time of the admission of the fluid. This is accomplished by providing an admission valve for the tool-head motor which is operated by the fluid and at a speed in proportion to the pressure of the fluid so that upon a lower pressure a longer time interval is allowed to admit the fluid to the toolhead motor, while at a greater pressure of the fluid a shorter time interval is allowed to admit the fluid to the tool-head motor, thus insuring the admission of a substantially uniform quantity of fluid to the tool-head motor upon each reversal of the work-holder regardless of the pressure of the fluid existing at the reversals of the workholder motor.

As before stated the fluid necessary to move the tool-head is taken from the common supply, i. e., from the main port 56 in the valve body I3, and is delivered to the tool-head fluid motor cylinder after passing a fluid-operated admission valve shown at I02 (Fig. 16) and a manually-operated reversing valve I01 (Figs. 17 and 19) the reversing valve acting to divert the successive flows into one or the other end of the tool-head fluid motor whereby the tool-head is intermittently advanced or retracted as desired. This valve I01 also regulates the extent of the intermittent movements of the tool-head by regulating the amount of fluid admitted to the tool-holder motor so that the extent of the successive-feeds of the tool-head may be regulated; the valve being given an initial adjustment depending upon the character of the work for this purpose.

The valves governing the movements of the toolhead are located in the upper portion of the body I3 of the hydraulic valve control mechanism, it being one of the more specific objects of the invention to provide that the entire control of the improved grinding machine be centralized and housed within an easily removable unit. An explanation will be given also of the manner in which a continuous feeding movement is given the tool-head.

The reversing valve I01 not only governs the direction of the intermittent and continuous toolhead movements, but may be also manually adjusted to govern the maximum extent of the intermittent movements, while the valve I02 not only controls the timing of the tool-head intermittent movements but also insures that the intermittent movements will be to the maximum extent allowed by the valve I01. In the present invention, the movements are timed to occur when the workholder is reversed, as this feature allows the minimum of overrun of the work beyond the wheel and therefore permits the grinding of full length pieces of work.

The valve I02 is a cylindrical reciprocating valve closely fltted in a horizontal bore I 03 (Fig. 16) which intersects a port IOI (Figs. 16, 17 and 19) which conveys fluid from the port 56 by means of the port I00 (Fig. 17) to the reversing valve I01. The port IN is normally closed (Fig. 17) by either one of the solid portions of the valve I02, and thereby prevents movement of the tool-head during grinding operations except at the ends of the work-holder strokes when the grinding wheel is clear of the work.

The reciprocatory movement of the valve I 02 is merely a longitudinal shifting in its bore I03, between the limits presented by the stop pins I (Fig. 16) fixed in the plugs I06, under the impulse of fluid pressure admitted alternately to the ends of the bore I03, conveyed thereto, on the one hand, from the port 69' (Fig. 13) by the conduit H3 extending across the rear of the valve body I3, and on the other, from the port 81 (Fig. 13) through the conduit I I4, extending across the forward side of the body I3. Therefore the rear of the right end (Fig. 16) of the valve I02, is exposed to pressure conveyed from the right end of the pilot valve bore 66, while the forward or left and (Fig. 16) is acted upon by fluid conveyed from the left end of the pilot valve bore 66, so that as the pilot valve is shifted at Work-holder reversals, so also is the valve I02 given a single movement from one end to the other of its stroke for each movement of the pilot valve.

It was stated that the port MI is normally closed by the valve I02. Then to allow admission of fluid through this port IOI whereby the tool-head is moved at the proper time, the valve I02 is provided at its central portion with a fluid supply opening in the nature of a narrow circumferential groove I04. During the small space of time that the groove I04 is passing the ends of the port IN, a charge of fluid is permitted to pass through the port I M, and after the valve passes to the opposite end of the bore I 03, this port IOI is again closed by one of the solid portions of the valve. The quantity of fluid so admitted is very small because it is necessary only to overcome the friction of the tool-head slide and to force a similar small quantity from the opposite side of the tool-head motor piston. For this reason, the groove I04 is narrow, and

the valve I02 admits only the fluid that is able to pass therethrough during the short space of time that elapses while the groove I04 is passing the port IN. This time interval varies with the fluid pressure because with high pressure the valve moves quickly and thereby admits a predetermined quantity of fluid, while if the pressure is lowered, the valve moves ata slower rate and is thereby enabled to admit the same quantity of fluid, thus insuring the admission of a uniform quantity of fluid upon each movement of the valve regardless of the pressure of the fluid.

The tool-head hydraulic motor is put in the substantially locked condition by the valve I02 as the port IOI is always closed by the valve I02 except as noted, when the valve I02 is moved by impulses of fluid under the control of the pilot valve 23.

As before stated the reversing valve I01 is used to change the direction of the movement of the tool-head, this valve having therein a pair of curved ports I08 and I09 in circumferential alignment. In one position of the reversing valve I01 one end of the port I08 (Figs. 17, 19 and 20) is in alignment with the port IOI, while the other end of the port I08 is in communication with the port leading to the conduit 39 whereby fluid is then conveyed to the left hand end (Fig. 2) of the cylinder 34 of the tool-head fluid motor.

In order to exhaust the opposite end of the tool-head fluid motor while such movements are being made, the port I09- of the reversing valve I01 is in communication with the conduit II leading to the storage tank 49. The conduit H0 is therefore in communication by means of the reversing valve port I09 with the right end of the tool-head fluid motor (Fig. 2) through the medium of the vertically extending port II I (Figs...l'1, 19 and 20) and the horizontal port II2 (Fig. 19).

In Figs. 17, 19 and 20, the valve is shown admitting fluid as above described, which will move the tool-head to the right (Fig. 2) while in Fig;

21 the valve I01 has been partially rotated to the extent of one-quarter turn which reverses the direction and causes the tool-head to move to the left (Fig. 2). The port I08 in the valve I01 is then in alignment with the ports IOI and III and thereby causes a flow of fluid through the conduit 40 and thence through to the right hand end of the tool-head fluid motor.

Graduated tool-head movement It is advisable to vary the extent of the movements of the tool-head in view of the different grinding operations. In the present invention the movements may be varied from no movement whatever to a maximum movement of approximately two inches. This feature as before stated is also a function of the valve I01 in addition to.its already described function of changing the direction of the movement of the tool-head. Fig. 20 shows the position of the valve I01 for the maximum feeding movement while Fig. 23 shows a position by which a feed of much smaller extent is made, it being noticed that the port IM and the port 39' leading to the conduit 39 are partially closed, the same being true with regard to the ports III and I I0. This is provided for by merely permitting the valve I01 to be rotated through a smaller portion of a revolution. In order to provide a convenient means whereby the valve may be quickly and accurately positioned for feeds of definite extent, the following described mechanism is employed; v

The valve I01 is provided with a reduced diameter extension H8 on the forward end of which is secured a slotted arm I I0. Arranged for slidable'movement in the slot 1 of the arm H8 is a cross-head II8 having a cylindrical rearwardly projecting stop-pin H9. The pin II! is arranged to contact the angular lower edges I 20 of a cavity I2I in a fan-shaped member I22 which is secured to a hubbed extension I24 (Figs. 4 and 22) of the body portion I3. The edges I20 against which the pin II9 makes contact form an obtuse angle whose apex I25 is at some distance above the center ofrotation of the valve I01, whereby when the pin I I9 strikes the angular edges I20 at different radial distances,'the angular movement of the valve I01 is varied from a full port opening to a minimum as seen by the full line outline of the arm H6 in Fig. 20. It will also be seen that in swinging to the position as shown by the dot-dash outline (Fig. 20) the direction of flow is reversed without changing the effective port area.

In order to reduce the extent of feed, the port opening area is reduced as seen in Fig. 23 in which view the pin II9 was moved toward the center of rotation. The pin II9 will then make contact with the opposite side I20 at the same radial distance and the same fractional port area obtained. A convenient means for changing the position of the pin H9 is employed by the use of a threaded rod I26 radially and centrally dis posed in the slot I I1 of the arm I I6 and provided at its upper end with a knurled nut I 21. The threaded rod I26 is threaded through the center of the cross-head II8.

Continuous feeding At times during the grinding operation it is desirable to be able to move the tool-head in a continuous movement in either direction regardless of the work-holder position or whether the work-holder is in operation or not, as for example, in placing work upon the work-holder or in measuring the work thereon. This is accomplished by the use of a continuous feeding valve I28 (Figs. 17, 18 and 22) which operates within a partial rotation of about 90. In the present case the valve I28 is located in the same bore I30 in which the valve I 01 is located so that the two are concentrically aligned and the shaft II5 of the reversing valve I01 passes through the valve I28 and also through the tubular extension I.3I by which the continuous feeding valve I28 is rotated. Inasmuch as it maybe desirable to perform the continuous feeding movement at a time when the machine is in operation, at which time the intermittent movements are occurring at the ends of the strokes of the work holder, the valve controlling this function must act in combination with the admission valve I02 by which the intermittent tool-head movements are obtained. This is perhaps best explained by stating that. when a continuous feeding movement is made while the grinding machine is in operation, during which time the pilot valve 23 is causing the reciprocations of the intermittent feed valve I02 as before explained, the valve I28 controlling the continuous feeding overrides the functions of the valve I02, although the latter continues its reciprocations as before. This is accomplished by delivering fluid pressure to the port IOI at a point intermediate the location of the valve I02 and the tool-head hydraulic motor; in the present case it is between the valve I02 and reversing valve I01.

Referring to Fig. 17 there will be noticed a portion 01' a port I23. This port is also seen in Figs. 3, 4, 16 and 18. This port conducts fluid from the main supply port 56 to the continuous feeding valve I28. when the continuous feeding valve I28 is in the position as shown in Fig. 18

the port I23 is closed, but when partially rotated as shown in Fig. 17 the port I23 is placed in communication with the port I33 by means of a notch I32 machined in the cylindrical side of the valve I28. The extension I3I communicates with the port IOI (Fig. 17) by means oia horizontal port I33 whereby fluid is delivered to the tool-head fluid motor either through the

conduit

39 or 40 according to the position of the reversing valve I01; as seen in Fig. 17 the reversing valve I01 is in position to supply fluid to the conduit 38 from the port 58. Since the pressure in the port IOI during the time the continuous valve I28 is opened is equal on both sides of the valve I02, the valve I02 is inoperative insofar as supplying fluid to the tool-head motor is concerned and therefore the tool-head will be moved continuously to the right (Fig. 2). To move continuously to the left (Fig. 2) it is only necessary to manipulate the reversing valve I01 to the proper position and open the valve I 28 to the desired opening.

The valve I28 is actuated by means oi! a lever I34 (Figs. 1, 3, 4 and 1'7). A stop-pin I35 (Figs. 3 and 18) is inserted in the lever I34 and contacts with lugs I36 and I31 (Figs. 3 and 18) for con veniently placing the valve in fully open or fully closed position.

In operation the work-holder is started by means of the lever- 34 which manipulates the valve 58 which controls the work-holder motor which lever 94 is moved from its closed position as shown in Fig. 1 in an anti-clockwise direction to any point at which a desired rate of movement of the work-holder is obtained. The lever H6 is adjusted by means of the screw I26 to cause the stop-pin IIS to make contact with the angular sides I20 to provide a certain definite feeding movement of the tool-head in the direction desired. The operation continues until it is desired to change the direction of the. tool-head when the lever H3 is swung to the opposite side. If at any time a continuous movement of the tool-head is desired the lever I34, which manipulates the continuous feed valve I 28 is moved from its closed position seen in Fig. 1 to a point which will produce the desired rate of continuous movement, the direction of which is under the control of the lever I I6. Both the work-holder and the tool-head may be moved independently of each other and stopped at any point while the movement of the work-holder may be reversed manually if desired at any point by a manipulation of the reversing lever [8.

Having thus described my invention, I claim:

1. In a machine of the character described, a plurality of fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, and fluid admission means operated directly by fluid for admitting successive predetermined charges of the fluid to another of said motors also operable from the same source of fluid supply.

2. In a. machine of the character described, a plurality of fluid motors operating from the same source of fluid supply, manual means for regu lating the fluid supplied to one of said motors, fluid admission means operated directly by fluid for admitting successive predetermin d charges of the fluid to another of said motors also operable trom the same source or fluid supply, and a manually-operated reversing valve located between said fluid admission means and last-mentioned motor to direct the fluid admitted by said means to either end oi the cylinder of said'lastmentioned motor.

3. In a machine of the character described, two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means operated directly by fluid for admitting successive charges of the fluid to the other motor also operable from the same source of fluid supply, and a manually-operated valve located between said fluid admission means and the cylinder of said last-mentioned motor to regulate the quantity oi the successive charges of fluid and to also direct, the fluid to either end of the cylinder of said last-mentioned motor.

4. In a machine of the character described. two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one or said motors, fluid admission means for admitting successive predetermined charges of the fluid to the other motor also operable from the same source of fluid supply, and a manually-operated valve to by-pass the fluid by said fluid admission means to admit a continuous flow of fluid to the lastmentioned motor.

5. In a machine of the character described, two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means for admitting successive predetermined charges of the fluid to the other motor also operable from the same source of fluid supply, a manually-operated reversing valve located between said fluid admission means and lastmentioned motor to direct the fluid admitted by said means to either end of the cylinder of said last-mentioned motor, and a second manuallyoperated valve to by-pass the fluid by said fluid admission means and admit' a continuous flow of fluid to either end of the cylinder of said lastmentioned motor as determined by said reversing valve.

6. In a machine of the character described, two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means for admitting successive charges of the fluid to the other motor also operable from the same source of fluid supply, a manually-operated valve located between said fluid admission means and the cylinderof said last-mentioned motor to regulate the quantity of the successive charges of fluid and to also direct the fluid to either end of the cylinder of said last-mentioned motor, and a second manually-operated valve to by-pass the fluid by said fluid admission means and direct the same to said first-mentioned valve.

7 In a grinding machine, a reciprocable workholder, a fluid motor for reciprocating said workholder, meansfor regulating the supply of fluid to said motor to vary the speed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, a movable valve to admit successive charges of said fluid to said tool-holder motor, and means for operating said valve by the said source of fluid supply whereby the speed of the valve will be governed by the pressure of the fluid.

8. In a grinding machine, a reciprocable workholder, a fluid motor for reciprocating said workholder, means for regulating the supply of fluid to said motor to varythe speed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, a reciprocable valve member having an opening therein to admit successive charges of said fluid to said tool-holder motor during the reciprocating movements of said valve,

and means for operating said valve by the said source of fluid supply whereby the speed. of the valve will be governed by the pressure of the fluid.

9. In a grinding machine, a reciprocable workholder, a fluid motor for reciprocating said workholder, means for regulating the supply of fluid to said motor to vary the speed thereof, a movable tool-holder, a fluid motor for moving said toolholder, said motors having a common source of fluid supply, and reciprocable means operated by the same fluid source having a fixed opening to admit successive charges of fluid to said toolholder motor whereby the speed of said means will be in proportion to the fluid pressure to admit a uniform quantity of fluid through said opening at all speeds of said means.

10. In a grinding machine, a reciprocable work-holder, a fluid motor for reciprocating said work-holder, means for regulating the supply of fluid to said motor to vary thespeed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, a movable valve to admit successive charges of sa d fluid to said toolholder motor, and means for operating said valve by the said source of fluid supply whereby the speed of the valve will be governed by the pressure of the fluid and a manually-operated valve to by-pass the fluid by said first-mentioned valve to admit a continuous flow of fluid to the toolholder motor.

ii. In a grinding machine, a reciprocable workholder, a fluid motor for reciprocating said workholder, means for regulating the supply of fluid to said motor to vary the speed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, a reciprocable valve member having an opening therein to admit successive charges of said fluid to said tool-holder motor during the reciprocating movements of said valve, and means for operating said valve by the said source of fluid supply whereby the speed of the valve will be governed by the pressure ofthe fluid, and a manually-operated valve to by-pass the fluidby said first-mentioned valve to admit a continuous flow of fluid to the tool-holder motor.

12. In a grinding machine, a reciprocable workholder, a fluid motor for reciprocating said workholder, means for regulating the supply of fluid to said motor to vary the speed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, and reciprocable means operated by the same fluid source having a fixed opening to admit successive charges'of fluid to said toolholder motor whereby the speed of said means 13. In a grinding machine, a reciprocabie work holder, a fluid motor for reciprocating said workholder, means for regulating the supply of fluid to said motor to vary the speed thereof, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply,a movable valve to admit successive charges of said fluid to said tool-holder motor, and means for operating said valve by the said source of fluid supply whereby the speed of the valve will be governed by the pressure of the fluid, a manually-operated reversing valve located between said first-mentioned movable valve and the cylinder of the tool-holder motor to direct the fluid admitted to either end of the cylinder of the tool-holder motor, and a second manuallyoperated valve to by-pass the fluid by said firstmentioned valve and admit a continuous flow of fluid to either end of the cylinder of the toolholder motor as determined by said reversing valve.

- 14. In a grinding machine, a work-holder, a fluid motor for moving said work-holder, a movable tool-holder, a fluid motor for moving said tool-holder, said motors having a common source of fluid supply, a valve to control the fluid which operates the work-holder motor, a pilot valve for controlling said flrst valve, a third valve for con trolling the fluid which operates the tool-holder motor also controlled by said pilot valve, said valves all being mounted as a single removable unit.

, 15. In a grinding machine, a fluid motor for operating the work-holder, another fluid motor for operating the tool-holder, said motors being supplied from a common source of fluid, a valve operated by said fluid to reverse the work-holder motor, a valve operated by said fluid to admit successive charges of fluid to the tool-holder motor, a manually-operated reversing valve between said last-mentioned valve and the tool-holder motor; said motors and valves being operated from the same source of fluid supply, said valves being mounted as a unitary removable structure.

16. The combination of a work-holder motor, a tool-holder motor, both of said motors being operated from the same source of fluid supply, and a unitary removable valve structure consisting of a main valve to control the fluid supplied to the tool-holder motor and operated by the fluid, a pilot valve operated by the work-holder for controlling said main valve, a reciprocating valve to admit successive charges of fluid tothe toolholder motor, a manually-operated reversing valve between said last-mentioned valve and the toolholder motor, and a second manually-operated valve to by-pass the fluid by the reciprocating tool-holder admission valve and direct the same through the reversing valve in a continuous flow.

17. A surface grinding machine comprising a base, a work supporting table thereon, a rotatable grinding wheel, a wheel slide to support said wheel for a transverse movement relatively to the table, a vertically movable slide to support said wheel slide for movement toward and from the table, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve arranged to change the direction of flow of fluid under pressure to and from said cylinder so as to change the direction of movement of the table, 'a second piston and cylinder operatively connected to traverse said wheel slide, and a device operatively connected to said second cylinder which is actuated directly by fluid at an end of the table stroke to cause .a flow of fluid to said second cylinder to cause a transverse movement of the wheel slide relatively to the table.

18. A surface grinding machine comprising a base, a work supporting table thereon, a rotatable grinding wheel, a wheel slide to support said wheel for a transverse movement relatively to the table, a vertically movable slide to support said wheel slide for movement toward and from the table,- a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve arranged to change the direction of movement of said table, adjustable dogs on said table to control the actuation of said valve, a second piston and cylinder operatively connected to traverse said wheel slide, a second valve which is operatively connected to cause a transverse movement of the wheel slide relatively to the table, and a third valve operable to supply fluid to actuate the second valve at each reversal of the table so as to traverse the grinding wheel a distance at each end of the table stroke.

19. A surface grinding machine comprising a base, a work supporting table thereon, a rotatable grinding wheel, a wheel slide to support said wheel for a transverse movement relatively to the table, a vertically movable slide to support said wheel slide for movement toward and from the table, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve, arranged to change the direction of movement of the table, a second piston and cylinder operatively connected to traverse said wheel slide, a second valve operatively connected to said second cylinder which is actuated at each end of the movement of the table to cause a transverse movement of the wheel slide relatively to the table, and a third valve in said system arranged when closed to cause fluid to flow under pressure from said second valve to intermittently traverse the wheel slide or when open to nullify the effect of said second valve and pass the fluid directly to the second cylinder to continuously traverse the wheel slide.

20. A surface grinding machine comprising a base, a work supporting table thereon, a rotatable grinding wheel, a wheel slide to support said wheel for a transverse movement relatively to the table, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve arranged to change the direction of flow of fluid under pressure to and from said cylinder which acts to change the direction of movement of the table,

a second piston and cylinder operatively connected to traverse said wheel slide, a second fluid operated valve operatively connected to said second cylinder to supply successive charges of fluid thereto, a third valve-operable at the end of each movement of the table to supply fluid to said second valve to operate the same.

21. In amachine of the character described, a. plurality of fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, and fluid admission means operated directly by fluid for admitting successive charges of the fluid to another of said motors also operable from the same source of fluid supply.

22. In a machine of the character described, a plurality of fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means operated directly by fluid for admitting successive charges of the fluid to another of-said motors also operable from the same source of fluid supply, and a manually-operated reversing valve located between said fluid admission means and last-mentioned motor to direct the fluid admitted by said means to either end of the cylinder of said last mentioned motor.

23. In a machine of the character described,

two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means for admitting successive charges of the fluid to the other motor also operable from the same source of fluid supply, and a manuallyoperated valve to by-pass the fluid by said fluid admission means to admit a continuous flow of fluid to the last-mentioned-motor.

24. In a machine of the character described, two fluid motors operating from the same source of fluid supply, manual means for regulating the fluid supplied to one of said motors, fluid admission means for admitting successive charges of the fluid to the other motor also operable from the same source of fluid supply, a manually operated reversing valve located between said fluid admission means and last-mentioned motor to direct the fluid admitted by said means to either end of the cylinder of said last-mentioned motor, and a second manually operated valve to by-pass the fluid by said fluid admission means and admit a continuous flow of. fluid to either end of the cylinder of said last-mentioned motor as determined by said reversing valve.

25. A surface grinding machine comprising a base, a work supporting table thereon, a rotatable grinding wheel, a slide to support one of said members for a transverse movement relatively to the other, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve arranged to change the direction of flow of fluid under pressure to and from said cylinder which acts to change the direction of movement of said table, a second piston and cylinder operatively connected to traverse said slide, a second fluid operated valve operatively connected to said second cylinder to supply successive charges of fluid thereto, and a third valve operable at the end of each movement of the table to supply fluid to said second valve to operate the same.

WILLIAM G. BALDENHOFER.