US2288153A

US2288153A - Dressing mechanism

Info

Publication number: US2288153A
Application number: US303569A
Authority: US
Inventors: Edward W Bullock
Original assignee: Gleason Works
Current assignee: Gleason Works
Priority date: 1939-11-09
Filing date: 1939-11-09
Publication date: 1942-06-30
Anticipated expiration: 1959-06-30

Description

June 30, 1942. E. w. BULLOCK DRESSING MECHANISM Filed Nov. 9, 1939 7 Sheets-Sheet l Snvcntor I EDWHED \M BULLOCK 85 E E 3 attorney June 30,1942. 5 w BULLOCK 2,288,153

DRESS ING MECHANISM Filed Nov. 9, 1959 7 Sheets-Sheet 2 I Zhwcutor EDWHED W EULLOCK June 30, 1942. w BULLOCK 2,288,153

DRESS ING MECHANISM Filed Nov. 9, 1939 7 Sheets-Sheet 3 Snnutor ED WEED W. BULLOCK Littorncu June 30; 1942 E, w BULLOCK 2,288,153

DRESS ING MECHANI SM Filed Nov. 9, 1939 7 Sheets-Sheet 4 Enventor EDWARD W. BULLOCK attorney June 1942- E. w. BULLOCK DRESSING MECHANISM Filed Nov. 9, 1939 '7 Sheets-Sheet 5 Summer EDWHED W BULLOCK mum! 7 Sheets-Sheet 6 E. w. BULLOCK DRESSING MECHANISM Filed Nov. 9, 1939 June 30, 1942.

lhwentor EDWHED W BULLOCK I I i Gnome} June 30, 1942. E. w. BULLOCK DRESSING MECHANISM Filed Nov. 9, 1939 '7 Sheets-Sheet 7 Zuwcntor EDWHRD W BULLOCK attorney Patented June 30, 1942 UNITED tea OFICE DRESSING MECHANKSM of New York Application November 9, 1939, Serial No. 303,569

13 Claims.

The present invention relates to dressing mechanisms and particularly to mechanism for dressing the sides and tip of a grinding wheel such as is used in the grinding of gears. In a more specific aspect, the invention relates to mechanism for dressing the sides and tip of a cupshaped grinding wheel such as is employed in the grinding of Formate (non-generated) spiral bevel and hypoid gears.

One object of the invention is to provide a mechanism for simultaneously dressing the sides and tip of a grinding wheel which will be simple and compact in its construction.

Another object of the invention is to provide a dressing mechanism having separate tools for dressing opposite sides of the wheel in which the two tools are actuated simultaneously on movement of a single actuating member.

A further object of the invention is to provide a dressing mechanism having separate side and tip dressers in which the tip dresser is actuated by a separate fluid-pressure actuated mechanism from that employed in actuating the side dressers but in which the actuating mechanisms are so connected together that they may be controlled from a single control valve.

A further object of the invention is to provide a dressing mechanism having separate side and tip dressers in which the dressers are so mounted as to operate simultaneously in a single radial plane of the wheel so that the dressin mechanism may be mounted at a convenient point on the grinding machine and the wheel may be swung up to the dressing mechanism for dressing. This arrangement is particularly advantageous for dressing a cup-shaped grinding wheel in a single dressing position.

Another object of the invention is to provide a dressing mechanism in which the movement of the side and end dressers are interlocked so that their movements will occur in proper sequence and the dressing tools will not interfere with one another in their operation.

Another object of the invention is to provide a dressing mechanism having separate side and end dressers in which the end dresser may be so moved as to dress not only the tip of the wheel but also to form rounds at the junctures of the sides of the wheel with the tip. This is necessary where the wheel is to be used for grinding the bottoms as well as the sides of the tooth spaces of a gear such as is required with bevel gears employed in aeroplane drives.

Still another object of the invention is to provide a dressing mechanism of the character described in which the dressing of the tip of the wheel and the rounds at the junctures of the sides and the tip may be efiected by a continuous movement of a single dressing tool.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Fig. 1 is a front elevational view, with parts broken away, showing the dressingmechanism of the present invention mounted on a known type of grinding machine for dressing a cupshaped grinding wheel;

Fig. 2 is a side elevation of the dressing mechanism, looking at right angles to the view of i Fig. 3 is a fragmentary vertical sectional view of the dressing mechanism, showing particularly the side dressers and the means for actuating the same, the view being on an enlarged scale; Fig. 4 is a view on an enlarged scale, showing particularly the enddressing mechanism, parts being broken away;

Fig. 5 is a fragmentary plan view, showing the positions of the side dressers and their connection to the actuating plate;

Fig. 6 is a side elevation on an enlarged scale of one of the arms which carries a side dressin tool and further illustrating the connection of this arm with the actuating plate;

Fig. 7 is a fragmentary sectional view taken. at right angles to the view of Fig. 4, and showing further details of the mounting of the end dresser;

Fig. '8 is a fragmentary view, partly in section and partly in plan, showing theend dressing mechanism and particularly the cam-rail for controlling the operation of the same;

Fig. 9 is a fragmentary perspective view of the cam-rail;

' Fig. 10 is a transverse sectional view through the cylinder and rotary piston for actuating the end dresser;

Fig. 11 is a sectional view of a modified hydraulic actuating mechanism for the end dresser;

Fig, 12 is a diagrammatic view illustrating the movements of the side and end dressing tools;

and

Fig. 13 is a diagrammatic view showing the hydraulic connections between the side and end dressing mechanisms.

The dressing mechanism of the present invenion has been illustrated in the drawings as applied to a semi-automatic grinding machine of the type described in the Bullock et a1. U. S. Patent No. 2,099,674, of November 23, 1937.

This type of machine is designed to grind spiral bevel and hypoid gears with a cup-shaped grinding wheel. The wheel is rotated on its axis and simultaneously swung back and forth in a limited working path to cause it to grind the side tooth surfaces of a gear from end to end. The axis about which the wheel swings is the axis of lengthwise curvature of the sides of the gear teeth. Ordinarily opposite sides of a tooth spaces are ground simultaneously. When the sides of a tooth space have been finished, the wheel is withdrawn from engagement with the gear and the gear is indexed to bring a new tooth space into position to be ground.

To dress the grinding wheel, the wheel is swung clear of the blank an extended distance beyond its normal working path to dressing position. The dressin mechanism of the present invention is intended to be substituted, for the dressing mechanism shown in the patent above mentioned. It is intended to be positioned on the grinding machine at a suitable point. so that when the wheel has been swung to dressing position, the dressing mechanism. may be actuated to dress the wheel.

The dressing mechanism illustrated in the accompanying drawings comprises, as already indicated, a pair of side dressing tools and an end dressing tool. The three tools are mounted so that the mean points of their movement lie in the same plane so that the sides and tip of the wheel can be dressed simultaneously and it is not necessary to move the wheel. to one position to dress its sides and to another position to dress its tip. The side dressing tools are mounted upon a pair of'swinging arms which are connected to opposite sides of a plate that is secured to a rec tilinearly reciprocable hydraulically actuated piston. When the piston is reciprocated, the side dressers are swung simultaneously in opposite directions across the inside and outside surfaces of the wheel, respectively, to dress the same. The length of the arms may be made such that the side dressing tools are swung on arcs of large radii so that for the height of side surface to be dressed, the dressing tools move in arcs very closely approaching straight lines. Thus side surfaces may be dressed on the wheel, which are to all practical intents and purposes, of straight profile. The side dressers are adjustable for pressure angle and diameter of the wheel to be dressed.

Two different modifications of the end dressing mechanism are shown in the drawings. In one embodiment, the end dresser is mounted on an arm which is rigidly secured to a rotary piston that is oscillatable by fluid pressure. In the other embodiment, the end dresser'is mounted on an arm which is rigidly secured to a shaft that is oscillatable on reciprocation of a rectilinearly reciprocable piston. Each embodiment is intended to be pivotally mounted in a support that is adapted to be mounted on the grinding machine for adjustment thereon to suit the diameter and height of the Wheel to be dressed. An arcuate cam-rail is secured to this support. The arm, which carries the end dressing tool, also carries a follower which engages this camrail. The cam-rail has two flat surfaces connected by a rise and is so located on the machine that the rise is in substantial alignment with the tip of the grinding wheel when the grinding wheel is in dressing position.

The rotation of the piston or of the shaft that carries the end dresser causes the end dresser to move from one side of the Wheel to the other. In the first part of its movement, the follower rides on a fiat surface of the cam rail and the only movement imparted to the end dresser is an arcuate movement causing it to dress a round at one side of the wheel. Then the follower rides up on the rise of the cam-rail. This causes the whole dressing carrier to be swung about its pivot, moving the dresser in a plane across the tip of the wheel to dress the same. Then the follower rides again on a flat surface of the camrail, dressing a round at the opposite side of the wheel.

The pistons which actuate the side and end dressers are interlocked in such a way that movement of one causes movement of the other. The arrangement is such that the movement of each dressing tool can be completed without in terference with the other tools. The operation of both the side and the end dressers is controlled from a single valve.

Reference will now be had to the drawings for a more detailed description of the invention. denotes the upright or. column of the grinding machine, 2| the oscillatable quill which is journaled in this column and W the grinding wheel which is journaled in the quill. As already described, the grinding wheel is rotated on its axis and the quill is oscillated to effect; the grinding of side tooth surfaces of a spiral bevel or hypoid gear. When the grinding wheel is to be dressed the quill is swung far enough to bring the wheel into operative relation with the dressing mechanism.

Mounted on the column 20 for rectilinear adjustment thereon is a bracket 22 (Figs. 1, 2 and 3). This bracket is adapted to be secured to the column in any adjusted position by means of T-bolts (not shown) which engage in the T-

slots

24 and 25 provided in the upper and outer faces of the column. A cylinder 26 is formed integral with the bracket 22 and a piston 2'! is mounted to reciprocate in the cylinder. The piston has rods 28 and 29 formed integral therewith and projectingv from opposite ends thereof. The rod 28 projects through an end plate which is secured to the cylinder by screws 3| and the rod 29 projects through an end plate 32 which is secured to the cylinder by screws 33.

Guide members

34 and 35, respectively, are secured to the

end plates

30 and 32, respectively, by

screws

36 and 31, respectively. These guide members serve to guide the piston in its movements. The rod 28 is keyed to the guide member 34 so that the piston is held against rotation as it reciprocates.

A pair of

armsv

40 and 4| are formed integral with the cylinder 26 and project from diametrically opposite sides of the cylinder. There is a bearing member 42 (Figs. 1, 3 and 5) mounted on the under surface of the arm 40 for angular adjustment thereon about an axis coinciding with the longitudinal axis of the piston 21. There is a similar bearing member 43 mounted on the under side of the arm 4| for angular adjustment thereon about this same axis. The bearing member 42 has a tongue 44 that is adapted to engage in an arcuate T-slot 45 which is formed in the under surface of the arm 40 and this bearing member is adapted to be secured in any adjusted position on the arm 40 by T-bolts 46 which engage in this slot. The bearing member 43 has a similar tongue 41 engaging in a similar T-slot 48 formed on the under surface of the arm 4| and this bearing member is adapted to be secured in any adjusted position on the arm M by T-bolts 49 which engage in the T-slot 4B. The

arcuate slots

45 and 48 are concentric with the axis of longitudinal movement of the piston 21.

J ournaled in the bearing member 42 on spaced

roller bearings

50 and 5| is a shaft 52. A similar shaft is similarly journaled in the bearing member 43. To these two shafts are keyed the

arms

54 and 55, respectively. Each of these arms has a split clamp formed in its lower end and in these clamps are fastened the diamonds 56 and 51, respectively, for dressing the inside and outside surfaces, respectively, of the grinding wheel W.

There is a plate 50 mounted on the lower end of the piston rod 29 and held against movement relative thereto by the nut which threads onto the piston rod. The arms 54 and'55 are opera-- tively connected to this plate 60 at opposite sides of the piston rod. Each arm has a pair of ears 62 and 63 (Fig. 6) formed integral with it. A pin 65 is threaded into the car 63 to engage the under face of the plate 60. In the other car there is mounted a pin 66. This pin is held resiliently in engagement with the upper face of the plate 60 by a coil spring 61 that is interposed between the pin and a nut 68 which threads into the ear. The two arms are of similar construction and the construction of one only, is therefore, shown in detail in Fig. 6.

By loosening the pin 65 either

arm

54 or 55 may be adjusted with reference to the plate 60 as the corresponding bearing

member

42 or 43 is adjusted about the longitudinal axis of the piston 21. Hence, the diamonds may be readily adjusted, by angular adjustment of the bearing members, to dress'side surfaces of any desired pressure angle and included angle on the grinding wheel, as will be clear from Fig.- particularly.

The resilient connection of each arm with the plate 60, which is formed by the spring-pressed pin 66, allows of pivotal movement of the arm as the plate moves rectilinearly under actuation of the piston 21. It will be seen, then, that as the piston 21 is moved in one direction or the other, the

arms

54 and 55 will be swung inopposite directions to pass the diamonds 56 and 51 across the inside and outside surfaces respectively, of the rotating grinding wheel to dress'these' surfaces.

Bolted to the upright or column 20, as by means of bolts 10 is a plate 1| (Figs. 1, 2 and 4). Mounted on this plate for rectilinear adjustment thereon is a plate 12. The plate 12 is adjusted on the plate H by rotation of the screw shaft 13 which is journaled in a lug 14 that is integral with the plate 11 and which threads into a lug or block 15 which is integral with the plate 12. The plate 12 is guided in its adjustment'on the plate 1| by a tongue 10, which is formed on the back of the plate 1.2 and which engages in a complimentarily shaped slot 11 formed in the front face of the plate 11. The plate 12 is secured in any adjusted position on the plate 1| by means of the bolts 18 which pass through elongated slots 19 in the plate 12 and which thread into the plate 1|.

The plate 12 is formed with a right angularly forwardly projecting arm 80. Mounted on this arm for rectilinear adjustment thereon in a direction at right angles to the direction of adjustment of the plate 12 is a carrier or support 82. The carrier or support is adjustable on the arm 80 by means of a screw shaftv 83 (Fig. 1) which is journaled in the carrier member and which threads into a nut (not shown) on the arm 80. The carrier is guided in this adjustment on the arm 90 by a tongue 84 which engages in a slot in the arm and the carrier is secured in any adjusted position on the arm 80 by the bolt 85 which passes through an elongated slot 86 in the arm 80 and which threads into the carrier.. Adjustment of the carrier on the arm may be made precisely by interposing Johannson blocks or other suitable gauges between the pin 81 which is fixed to the carrier and the pin 88 which is fixed to the arm.

The carrier 82 is formed with a pair of spaced lugs or ears 90 (Figs. 1, 4 and 7). The ears 90 serve as supports for the trunnion-members or pivot-pins 92 which project laterally from opposite sides of the head 93 in which the pins are mounted. The head 93 is secured to an end plate 94 (Fig. 4), which, in turn, is fastened to a cylinder 95. An end plate 96 is secured to the lower end of the cylinder and a stop-plate 91 is secured to the under side of this end plate. A cap-member 98 is secured to the under face of the stop plate. The trunnions 92 are journaled on antifriction bearings 9| in the ears 92.

Journaled on spaced anti-friction bearings I00 and IOI in the

end plates

94 and 98 is a shaft I02. This shaft projects through the head member 93 and pinned to the projecting part of the shaft is an arm I04. This arm is formed at its upper end with a split clamp in which the end dressing diamond I05 is secured by the bolt I06.

The arm I04 is formed with a lateral projection I08. This projection I08 is provided with a longitudinal slot I09 which extends radially of the shaft I02 and in which is slidably mounted a stud I I0. Integral with the stud I I0 is a blocl; I II. A screw shaft II2, which is journaled in thelateral projection I08 and which threads into the stud IIO, serves to adjust the block III longitudinally in the slot I09 and radially of the shaft I02. A nut I I3 which threads onto the stud and a washer II3' which is interposed between the nut and the upper face of the projection I08, serve to hold the stud in any adjusted position.

The block I-II carries a pin II4 on which is mounted a roller H5. The roller H5 is adapted to ride on a cam-rail II6 (Figs. 4, 2, 1, 8 and 9). This cam-rail is secured by screws I I1 to a flange I I8 formed integral with the carrier 82.

The cam rail H6 is semi-circular in shape and is mounted to be concentric with the axis of the shaft I02. The cam-rail IIO has a dwell portion IIB which extends for approximately 90, a dwell portion II9 that also extends for nearly 90, and a short beveled rise portion I 20 which connects the two dwell portions.

- When the shaft I02 is oscillated, then the roller II5 rolls along the dwell portion H8 of the cam rail until it comes to the rise I20. up on this rise onto the higher dwell portion 9. When the roller is riding on either dwell portion H8 or II9 the only movement imparted to the diamond I05 and to the .arm I04, which carries the diamond, is a rotational movement about the axis of the shaft I02, but when the roller is riding on the rise I20 of the cam rail, the whole housing comprising the head 93, endplate 94, cylinder 95, end-plate 96, stop-plate 91 and cap member 98 is rocked about the trunnions 92. This causes the diamond to be swung in the planeof the tip of the grinding wheel to dress a planesurface on the tipv of the wheel. When th roller is riding on the dwell portion Then it rides III! of the cam, then, the diamond I will dress a round at the juncture of the outside surface and the tip of the wheel; when the roller is riding on the rise I23, the diamond will dress the tip of the wheel; and when the roller is riding on the dwell portion I I9 of the cam-rail, the diamond will dress a round at the juncture of the tip of the wheel with the inside surface of the wheel.

To permit dressing wheels of different pointwidths at their tips, the rise I29 is made so that it is of increasing height from front to rear of the cam-rail as is clearly illustrated in Fig. 9. By adjusting the block Iii laterally on the projection I68 of arm I94 through manipulation of the screw shaft II2, the position of the roller from front to back of the cam-rail can be ad ju'sted. Thus, the point at which the roller rides up on the rise I20 can be predetermined, and thereby the amount of swinging movement of the diamond about the trunnions 92 can be adjusted in accordance with the point-width of the grinding wheel which is to be dressed. The roller H5 is shaped to have, as shown, a V-profile so that it will have only point contact with the cam rail. Thus when it is positioned at any given radial distance from the axis of the shaft I 02 it will transmit precisely to the arm I64 and diamond I 65 the amount of the lift at that radial distance of the rise portion I20 of the cam rail.

Rotational movement may be imparted to the shaft I82 in various ways. In one embodiment of the invention, there is a sleeve I29 (Figs. 4, and 13) keyed to the shaft 402 where the shaft passes through the cylinder 55. A paddle member I30 is formed integral with this sleeve. A partition member I3! is secured to the cylinder 95 by screws I32 to limit the movement of the paddle member in the cylinder. The paddle member constitutes a rotary piston which is adapted to be moved in one direction or the other under fluid pressure. Fluid pressure may be applied to one side of the paddle member through a pipe I33 and duct I34 and it may be applied to the other side of the paddle member through a pipe H5 and duct I36.

To prevent leakage of the motive fluid past the paddle member, a block of rubber or other suitable material i3? (Fig. 10) is mounted in a suitable recess in the periphery of the paddle member to engage the interior wall of the cylinder as the paddle member is rotated in the cylinder. A similar block I38 is mounted in a suitable recess in the partition member I3I to engage the periphery of the sleeve I29 as the paddle member rotates in the cylinder. The two blocks I31 and I38 are held in operative positions by fluid pressure. There is a duct I40 drilled transversely through the paddle member I80. Seats are provided in this duct for two ball-check valves MI and I42 and a coil spring E43 is interposed between the two ball check valves to normally seat both valves. The two valves are so arranged that one of them closes the duct I40 against flow of the motive fluid in one direction and the other against flow of the motive fluid in the opposite direction. The duct I40 communicates with a short duct 155 that leads to the back of the block I3'i.

There is a duct I50 drilled transversely through the partition member I 3|. A pair of ball check valves I5I and I52 are seated in this duct to normally shut off flow of the motive fluid, respectively, in opposite directions through the duct. A coil spring I53, which is interposed between the two check valves, serves normally to seat the valves. The duct I50 communicates with a short duct I54 which leads to the back of the block I38. When the pressure fluid is applied to the upper face of the paddle I30, as viewed in Fig. 10, it causes the paddle member to be moved in a counterclockwise direction. At the same time the motive fluid flows through the upper end of the duct I40, forcing the Valve I4I open. Thence it flows into the duct I45 to force and hold the block I31 against the inside wall of the cylinder as the paddle member rotates in the cylinder. At the same time, also, the motive fluid flows through the left hand end of the duct I50, forcing the valve I 5| open and flowing into the duct I54 to hold the block I 38 against the collar portion of the paddle member. When the direction of flow of the pressure fluid is reversed, the paddle member is moved in a clockwise direction in the cylinder. At the same time, the pressure fluid flows through the ducts I40 and I 50, forcing the check valves I42 and I52, respectively, open to allow flow of the fluid into the ducts I45 and I 54, respectively, to hold the blocks I31 and I38 again in operative position. Thus in either direction of rotation of the paddle member, leakage from one side to the other of the paddle member is prevented.

The limits of rotational movement of the paddle member in opposite directions in the cylinder 95 can be determined by adjusting the stops I60 (Figs. 1 and 2) in the end plate 91. These stops are threaded into the end-plate and adapted to abut against opposite end faces of the block I62 (Figs. 2 and 4) which is keyed or otherwise fastened to the shaft I02.

The movements of the rectilinearly reciprocable piston 21 (Fig. 3) and of the rotatable piston I30 (Fig. 10) are controlled from the same valve I65 (Figs. 1 and 13). Moreover, these pistons are interlocked so that their operations occur in sequence. One way in which the pistons may be hydraulically connected is illustrated diagrammatically in Fig. 13.

The valve I65, which is manually operable, is mounted for reciprocation in a valve chamber I66 which may be secured at any suitable point on the machine. The valve is normally held in the upper position shown in Fig. 13 by a coil spring I61 which is interposed between the bottom of the valve casing and the bottom of the valve stem. The pressure fluid is pumped to the valve casing through a duct I68. This duct is connected with the fluid pump of the machine. The motive fluid is exhausted from the valve casing either through the duct I69 or the duct I10. These two ducts communicate with the duct I12 which leads back to the sump of the machine. The valve is connected to the cylinder 95 at one side of the rotary piston or paddle I30 by the duct I 35, as already described. The valve is connected to the upper end of the cylinder 26 by a duct I14 and the pipes I15 and I16 (Figs. 1 and 3). The lower end of the cylinder 26 is connected to the cylinder 95 at one side of the piston or paddle I 30 by the piping I11 and I18 and the duct I19.

Fig. 13 shows the positions of the parts when the valve is in normal, inoperative position. To actuate the dressing mechanism, the operator depresses the valve I65 by pushing on the knob I80. Then the pressure fluid flows from the duct I68 into the duct I 16, forcing the piston 21 downwardly in the cylinder 26. The downward movement of the piston forces the motive fluid out of the lower end of the cylinder 26 through the duct I19 into the cylinder 95, causing the paddle I30 to be rotated counterclockwise in the cylinder 95. This movement of the paddle forces the motive fluid on the right hand side of the paddle out of the cylinder 95 through the line I35 and the ducts I69 and I12 back to the sump of the machine.

The downward movement of the piston 21 causes the

arms

54 and 55 to be rocked in opposite directions about their pivots to dress the sides of the grinding wheel. The counterclockwise movement of the paddle I30 causes the arm I04, which carries the end dresser I to be swung about the axis of the shaft I02, moving the roller II5 over the surface of "the cam rail II6 to cause the end dresser to dress the tip of the wheel and rounds at the junctures of the inside and outside surfaces of thewheel with the tip as already described.

When the operator releases the valve I65, it moves upwardly again to the positionshown'in Fig. 13 under actuation of the spring I61. vThis causes the line I35 to be put on supply from the line I68, causing the paddle I30 to be 'returned to the position shown in Fig. 13. As the paddle thus moves clockwise, it forces the oil out of the cylinder 95 through the duct I19 into the lower end of the cylinder 26'returning the piston 21 to its upper position. The fluid exhausting from the upper end of the. cylinder 26 passes through the line I16 and ducts j'I10 and I12 back to the sump; 'In the return movement of the piston 21, 'the dressers'56 and 51 are swung back to starting position. In the return movement ofthe paddle I30; the roller Il5rides first over the dwell portion II8 of the cam rail. IIB causingthe end dresser to be swungabout the axis of the shaft I02. .Then the rollerrides up on the rise I20 of the camrail, rocking the whole end dressing mechanism about the axis of the trunnions 92. Finally; the roller rides. on the, dwell II9 of the cam-rail, causing the end dresser to move again about the axis of the shaft I02.

. To take care of the difference in oil capacity betweenthe cylinders 95 and 26 a duct I85,.may

be provided to communicate with the, cylinder 95 at a point'bet'ween thefducts I19v an'dfl35. This duct is normally. closed by a ball check valve I86 .which is held, in operativepositio'n bythe coil spring I81. The duct I85 is connected with the duct I19through ducts I90, I9I and I92 drilled in the cylinder'housing 95.

'When the line I35I ison supply, the paddle member .I301ismoved in a clockwise direction to be returned to the position shown in Fig. 13 and any surplus motive fluid pumped through the'line I35 will forcethe check'valve I86 open and'may exhaust through the ducts I90, I9I

and I92 into the line I19 Whneit flows into the cylinder 26. r

' The paths of movement of the severaljdiamonds in'the dressing of a'wheel are illustrated diagrammatically in Fig. 12. Each of the diamonds 56.51 and I05 are shown in the'positions which they occupy at the start of the dressing operation; As thepiston 21 moves'down'wardly in its cylinder 26, the diamond 56 is swung upwardly, moving in the plane 200 to dress the inside surface 20I of the grinding wheel. At

the same time the diamond 51 is swung downwardly in. the plane 202 to dress the outside surface 203 of the grinding wheel. At the same time,

also, the diamond I05 is swung first about the axis of the shaft I02 from the position I05 to I05 to dress a round at the juncture of the tip 205 with the outside surface 203 of the wheel. Then the diamond is swung about the axis of the trunnions 92 to move from the position I05 to the position I05" to dress the tip 295 of the wheel. Then the diamond is swung again about the axis of the shaft I02 from the position I05 to the position I05" to dress around at the juncture of the inside surface I and the tip 205 of the wheel. The described arrangement and movements. of the diamonds prevent them from interfering with one another, for before the diamond 51 has moveddownwardly to a point adjacent the tip ofithe wheel, the end dresser I05 will have moved to the position I05" clear of the path of the dresser 51. Moreover, the side dresser 56 will have moved upwardly in the plane 200 beyond the tip of the wheel before the end dresser has reached the position I05.

It will be obvious, of course, that the'end dressing mechanism may be'operated by a rectilinearly reciprocablepiston instead of a rotary piston. Thus, as shown in Fig.'11, a spur pinion 2 I0 may be secured to the shaft I02 in place of'the paddle member I30." Thi's'spur pinion 2H1 meshes with a rack 2ll'which"is'cut into one side of a reciprocable piston" 2I2'. "The piston H2 is mounted to reciprocate ma cylinder 2I3 bored in the cylinder housing 95"w'hich is substituted for the cylinder housing 95 ofFig. 4Q Thefiuid- ,pressureconnections'to' oppositeends of the cylinder 2I3 'maybe th' fsame'asthose already described for the .c'ylir'ider"95. 'Thus, the motive fluid may be adifiittedfto one end of the cylinder 2I3 from thediictI35'ithi'oughthe port 2 I5and it "ma be admitted to-[the opposite end of the cylinder 2I3 from theiduct" I19'thr'ough the port 2I6. .The shaft I021" will be rotated, then, in op osite" directions on movement of the "piston 2 12 opposite directions" and in'the manner similar to that already described.

A'port 2I1 is provided in thelcylin'der 2I3 between the ports 2I5 and H6 for a purposesimilar' toth'e purpose of provision ofthe port l85 in the c'ylinder95." Ache-ck valve 2I8 normally closes the port 2I1 under actuation of the coil spring 2I9. Surplus pressure fluid, however, may flow from the port MS through the pOrt ZI'I,

when the port 211 i's unc'overed in the travel of the piston 2I2. It will. flow then through the has already been indicated, the'adjustment of the bracket22 on'the column 20 permits of positioning the side-dressers 56 and 51 to suit the diameter of'the grinding wheel to be dressed and the adjustment, of the bearing members Q2 and .43 on the arms '40 and 4| permit of setting the side-dressers in accordance withthe pressure angles and included angle to be dressedon the sides of thewheel. The adjustment of theplate 12 on the plate 1I permits of positioning the end dresser'in accordancewiththe diameter of the wheel to be dressed. The adjustment of the carrier 82 on the arm of the plate 12 permits of positioning the end dresser in accordance with thejheight of the wheel. The adjustment of the block III on the projection I08 of the arm IIO permits of adjusting the end dresser to accommodate wheels of various point widths. Of course the lengths of the armsjd or 55 may be increased or decreased to; permit dressing curved profiles on the sides of the grinding wheel. Adjustment of the stops I60 permit of controlling the amount of swing of the end dresser to suit the wheel to be dressed. The dressing mechanism described, then, is capable of an extremely wide range of use.

Moreover, while the invention has been described in connection with a dressing mechanism for dressing a cup-shaped wheel, it will be understood that the dressing mechanism of this invention may be employed in dressing other types of wheels also. It will further be understood that while the invention has been described in connection with a particular embodiment thereof, it is capable of various further modifications. The present application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A dressing mechanism for dressing gear grinding wheels comprising a pair of supports, an arm journaled in each of said supports, a dressing tool mounted in one end of each arm, a plate, means connecting the plate with both of said arms, a reciprocable piston connected to the plate at a point intermediate the points of connection of said arms with the plate, and means for applying fluid pressure selectively to opposite ends of said piston to actuate said arms, said supports being adjustable angularly about the point of connection of the plate with the piston to adjust the planes of swing of the dressing tools relative to the wheel to be dressed.

2. A dressing mechanism for dressing gear grinding wheels comprising a reciprocable piston, a plate connected to the piston to reciprocate therewith, a pair of arms connected to the plate at opposite sides of the point of connection of the plate with the piston, supports On which said arms are pivotally mounted, dressing tools carried by said arms, said supports being adjustable angularly about the point of connection of the piston with the plate, and means for applying fluid pressure selectively to opposite ends of the piston.

3. A dressing mechanism for dressing gear grinding wheels comprising a cylinder, a piston rectilinearly reciprocable therein and having a piston-rod secured thereto which projects from one end of the cylinder, a plate connected to the projecting end of the piston-rod, a pivotally mounted arm, a dressing tool secured in one end of said arm, ears projecting from one side of said arm, and means resiliently connecting said ears with the plate to cause movement of the arm about its pivot on movement of the piston, and means for applying fluid pressure selectively to opposite ends of the piston.

4. A dressing mechanism for dressing a gear grinding wheel comprising an end dressing tool, means for swinging the dressing tool about one axis to move the tool from one side of a grinding wheel to the other and cause the tool to dress rounds at the junctures of the tip and opposite sides of the wheel, and means for swinging the dressing tool during the first-named swinging movement about an axis extending at right angles to the first axis and at right angles to the tip surface of said wheel to cause the dressing tool to dress the tip of the wheel.

5. A dressing mechanism for dressing a gear grinding wheel comprising a carrier, a support mounted in said carrier for pivotal movement about an axis extending at right angles to the tip surface of the grinding wheel, a shaft journaled in said support for oscillation about an axis extending at right angles to the-pivotal axis of said support, an arm secured to said shaft, an end dressing tool mounted on said arm, means for oscillating said shaft to cause said tool to dress rounds on the wheel at the junctures of the sides of said wheel with its tip, and means operable at a'predetermined point in the swinging movement of the shaft to swing said support on its pivot to cause the dressing tool to dress a plane surface on the tip of the wheel.

6. 'A dressing mechanism for dressing a gear grinding wheel comprising a carrier, a support mounted in said carrier for pivotal movement about an axis extending at right angles to the tip surface of the grinding wheel, a shaft journaled in said support for oscillation about an axis extending at right angles to and intersecting the pivotal axis of said support, an arm secured to said shaft, an end dressing tool mounted on said arm, a cam rail secured to the carrier and curved arcuately about the axis of said shaft, and a roller carried by said arm adapted to ride on one lateral face of the cam-rail, said cam-rail having a rise formed, on said lateral face at a point intermediate its ends to cause said support to pivot on its axis as the roller rides from one end of the rail to the other in the pivotal movement of the shaft.

7. A dressing mechanism for dressing gear grinding wheels comprising a carrier, a support pivotally mounted on said carrier, a shaft journaled in said support for oscillation about an axis extending at right angles to the pivotal axi of the support, an arm secured to said shaft, an end dressing tool mounted on said arm, an arcuate cam-rail secured to the carrier, a roller carried by the arm and adapted to ride on said cam-rail, said cam-rail having a rise formed thereon at a point in alignment with the tip of the grinding wheel, said rise being of increasing height from front to rear of the cam-rail, and means for adjusting the roller on said arm to permit engaging the roller with the cam-rail at a selected radial distance from the center of curvature of the cam-rail.

8. A dressing mechanism for a gear grinding Wheel comprising an end dressing tool, means for swinging the end dressing tool from one side of a grinding wheel to the other, and means for moving the dressing tool during part of said swinging movement about an axis extending at right angles to the tip surface of the grinding wheel to cause the tool to dress the tip surface of the grinding wheel.

9. A dressing mechanism for gear grinding wheels comprising a pair of side dressing tools and an end dressing tool, means for swinging one side dressing tool in a clockwise directionin a plane inclined to the axis of the wheel at the pressure angle of the side surface of the Wheel which is to be dressed by said tool, means for simultaneously swinging the other side dressing tool in a counterclockwise direction in a plane inclined to the axis of the wheel at the pressure angle of the other side surface of the wheel, means for simultaneously swinging the end dressing tool from the latter side of the wheel to the first side of the wheel, and means for moving the end dressing tool in a plane at right angles to the plane of said swinging movement during part of said swinging movement.

10. A dressing mechanism for gear grinding wheels comprising a side dressing tool and an end dressing tool, fluid pressure operated means comprising a cylinder and a piston movable therein for actuating each of the dressing tools, a single control valve for controlling the direction of application of fluid pressure to both of said pistons, means connecting the valve with one end of each piston so that when one end of one piston is on supply, one end of the other piston is on exhaust, and means connecting the opposite ends of the two pistons to one another so that movement of one piston in its cylinder causes movement of the other piston in the latters cylinder.

11. In combination, a cylinder, a shaft journaled in the cylinder, a paddle member secured to said shaft within said cylinder, a partition member secured in said cylinder, a seal member mounted in the paddle member to bear against the interior wall of the cylinder to prevent leakage past the paddle member, a seal member mounted in the partition member to bear against the paddle member to prevent leakage past the partition member, means for applying fluid pressure selectively to opposite ends of the paddle member to oscillate the shaft, and means for applying the pressure fluid to said seal members to hold them in operative position during rotation of the shaft.

12. A dressing mechanism for gear grinding wheels comprising a pair of pivotally mounted arms, a pair of dressing tools mounted in said arms to dress the inside and outside surfaces of a grinding wheel, respectively, and so arranged that when the arms are at mean point of their swing, the two dressing tools will lie in the same plane, a third pivotally mounted arm, an end dressing tool mounted on the third arm so that at a mean point of swing of said arm it lies in the same plane as the first two dressing tools, means for oscillating the three arms, and means for moving the third arm in a plane inclined to the plane of its swinging movement during part of its swinging movement.

13. A dressing mechanism for gear grinding wheels comprising an end dresser, means for moving the end dresser in a circular path lying in a plane containing the axis of the grinding wheel to cause the end dresser to. dress rounds at the junctures of the tip and opposite sides of the wheel, and means for moving the end dresser in a plane perpendicular to the last named plane and about an axis perpendicular to the tip of the wheel to cause the end dresser to dress a plane tip surface on the wheel.

EDWARD W. BULLOCK.