US1952458A

US1952458A - Abrading machine

Info

Publication number: US1952458A
Application number: US623402A
Authority: US
Inventors: Dwight C Page
Original assignee: Heald Machine Co
Current assignee: Heald Machine Co
Priority date: 1932-07-19
Filing date: 1932-07-19
Publication date: 1934-03-27
Anticipated expiration: 1951-03-27

Description

Match 27, 1934.

D. c. PAGE ABRADING MACHINE Filed July l9, 1952 4 Sheets-Sheet l uw m 0. 231? March 27, 1934. 0., CJPAGE ABRADING MACHINE.

Filed July 15, 1932 4 Sheets-Sheet 2 nm m (3. 33;: a, a, my

March 27, 1934.

D. C. PAGE ABRADING MACHINE Filed July 19, 1932 4 Sheets-Shet xmw , gmnntot March 27, 1934. c, PAGE 1,952,458

ABRADING MACHINE Filed July 19, 1932 4 Sheets-Sheet 4 gwuentov Dm m 0. PM

Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE ABRADING MACHINE Dwight C. Page, Worcester, Mass, assignor to The Heald Machine Company, Worcester, Mass., a corporation of Massachusetts Application July 19, 1932, Serial No. 623,402

25 Claims. (01. 51-50) the workpiece, to mount the workpiece in sep-' arate machines, the first of which procures a grinding operation on the workpiece to reduce the workpiece substantially to the desired size and the second of which operates to polish the ground surface in order to form a suitable finished surface on the workpiece. ble, particularly in machines in which the workpiece is clamped in a chuck, to mount the workpiece for rotation in the second machine so that it will rotate about the same axis of rotation about which it was rotated in the first machine and accordingly the polishing operation by the second machine does not result in a uniform polishing over the entire ground surface of the workpiece. Furthermore, the necessity for removal of the workpiece from one machine and for mounting it in the second machine to complete the abrading operation results in an appreciable loss of time. It is accordingly the principal object of the present invention to provide for successive abrading operations such V as a grinding operation and thereafter a polishing operation on the same surface of a workpiece and in a single machine by separate abrading members carried on the same rotating spindle.

According to the present invention, which is, in certain respects, an improvement on the copending application of Taylor, Quimby and Lippard, Serial No. 623,400, filed .July 19, 1932, now Patent No. 1,949,552, dated March 6, 1934; a plurality of abrading members are mounted in axially spaced relation on a rotating spindle. One of the members is positioned in operative relation to the surface of the workpiece to be operated upon and is maintained in that position during the preliminary grinding operation. The workpiece and the abrading members "are then 0 shifted axially relative to one another to bring It is practically impossi wheels and the workpiece, and for dressing the wheels to maintain suitable cutting surfaces.

One of the features of the invention resides in a novel mechanism for locating the separate abrading members successively in operative relation to the workpiece, this mechanism being a different form of mechanism from that shown in the above noted copending application. In accordance with this feature of the invention, the position of the carriage, which determines the position of the abrading members relative to the workpiece, is determined by stop members mounted on said carriage, and the stop members are shifted longitudinally of said carriage when it is desired to change the position of the abrading wheels relative to the workpiece as in positioning one of the wheels in engagement with the work and removing the other from operative engagement. The mechanism for shifting said stops on the table is preferably actuated by fluid under pressure.

An additional feature of the invention resides in mechanism by which a rough grinding operation and subsequently a slower finish grinding operation may be procured with one of said abrading members and a polishing operation thereafter procured with the other of said abrading members. Other and further objects and advantages of the invention will appear from the following detailed description taken in connection with the accompanying drawings in which:-

Fig. 1 is a front elevation of an abrading machine embodying the invention.

Fig. 2 is a diagrammatic view of the workpiece and abrading wheels in the position for the preliminary abrading operation.

Fig. 3 is a fragmentary elevation of the mecha-" nism by which the machine carriage is positioned and reciprocated, said mechanism being in the position for the preliminary abrading operation shown in Fig. 2.

Fig. 4 is a diagrammatic view corresponding to Fig. 2 with the workpiece and abrading wheels in a position for the final abrading or polishing operation.

Fig. 5 is a view similar to Fig. 3 with the parts in the position for the final abrading or polishing operation, shown in Fig. 4.

Fig. 6 is a vertical section along the line 6-6 of Fig. 5 looking in the direction of the arrows.

Fig. 7 is a sectional view through the crossfeed mechanism showing the structure by which the abrading wheels are withdrawn radially from the workpiece.

ersing movement between the abrading members and the workpiece. In the construction shown, the table 1 supports and carries a wheelhead 3 while the workpiece a which is to be operated upon is mounted in suitable supporting means on the workhead 4, the latter being carried by a bridge 5 which spans the slideways provided by the base for the longitudinal back and forth movement of the table 1. An abrading wheel spindle 6, which is suitably journaled in the wheelhead 3, is rotated in any suitable manner as by an electric motor 7 mounted on the table, and carries a plurality of abrading wheels 9 and 10 by which successive abrading operations on the same workpiece are procured. The workpiece a is mounted in a suitable work supporting member 8 carried by a spindle joumaled in the workhead 4, said spindle being rotated desirably at a slower speed than the spindle 6 in any suitable manner, not shown.

The reciprocations of the table 1 to cause the rotating abrading members to make the required internal traverse of the rotating workpiece may be imparted in any well-known manner as by the use of the fluid pressure controlling and nevering mechanism describedin United States Letters Patent No. 1,582,468, granted April 27, 1926 to Heald and Guild. Such mechanism is wellknown; it is sufficient to note, for purposes of the present application, that the driving means employed, be it hydraulic drive or any other type, procures the reversal of the table at each end of the normal working stroke by the use of spaced

adjustable dogs

11 and 12 carried by the table 1 and adapted alternately to engage and move a reversing lever 13 which latter, during the abrading operation, when either of the wheels is moving back and forth within the workpiece is situated between said reversing dogs in a position to be struck alternately by said dogs and by the resultant movement first in one direction and then in the other to effect a reciprocation of the table 1.

The crossfeed movement between the workpiece and the abrading wheels to feed said wheels laterally against the surface being ground is procured in this machine by lateral movement of the wheelhead 3 on the table 1 in any suitable manner as by the mechanism disclosed in Patent No. 1,682,673, granted August 28, 1928 to Taylor. It

is sufiicient to note that the wheelhead 3 is mounted on a cross-slide 14, Figs. 7 and 8, which is adapted to have a transverse movement on the reciprocatory table 1, and movement of the crossslide is procured by rotation of a crossfeed screw 15, the latter being suitably connected to the cross-slide 14. Rotation of the crossfeed screw is effected by a cam 16, Fig. l, adjustably mounted on a bracket 17 extending from the bridge 5. Said cam, during the reciprocation of the table 1, engages a roller 18 carried on a pivotally mounted arm 20 for rocking of said arm,'and the latter carries on the outer end thereof a pawl 21 which during the rocking of the arm 20 engages with a ratchet wheel 22 positively connected to the crossfeed screw for rotation of said screwsiCrossfeed movement of the abrading wheels is thus responsive to the reciprocatory movements of the table 1.

The abrading wheel spindle carries, as above stated, a pair of abrading wheels 9 and 10, the former constituting a wheel for grinding of the workpiece a substantially to the desired size, and the wheel 10 constituting a wheel suitable for polishing the workpiece to provide a suitable finished surface on said workpiece. In the operation of the machine, the abrading wheel 9 is first reciprocated longitudinally over the surface of the workpiece, as shown in Fig. 2 and, after the workpiece is ground substantially to the desired size, the workpiece a and abrading wheels are axially shifted relative to one another for the polishing operation during which the polishing wheel 10 is reciprocated over the surface of the workpiece, as shown in Fig. 4.

At the beginning of the grinding operation, the carriage 1 is moved longitudinally of the machine by the carriage actuating means to bring the grinding wheel 9 into operative engagement with the workpiece and the arrangement is such that the grinding wheel 9 is given a longitudinal traversing movement over the surface of the workpiece without causing the wheel 10 to engage said surface. The longitudinal traversing movement of said wheel 9 procures a transverse crossfeed movement of the grinding wheel against the surface of the work, as above pointed out, to procure a cutting action on said workpiece.

The reciprocation of the wheel 9 for the Tinding operation is controlled by the

spaced dogs

11 and 12 which, as above stated, are carried on a dog bar 23 on the front of the table 1 and the grinding operation of the wheel 9 on the workpiece is under the control of these dogs until the workpiece has been ground to a predetermined size which is smaller than the finished size, at which time, in response to entry of a roughing or preliminary gauge within the bore of the workpiece, an extended movement of the carriage is effected in order to procure a dressing operation on the wheels 9 and 10, the wheel 9 being thereafter returned to the original grinding position.

The extended movement of the carriage is procured in any suitable manner as by mechanism of the type fully disclosed in United States Letters Patent No. 1,682,672, issued August 28, 1928 to Guild, said mechanism being under the control of a gauge of the type disclosed in United States Letters Patent No. 1,532,302, issued April 21, 1925 to Conradson or in United States Letters Patent to Kempton and Gallimore No. 1,713,719, issued August 15, 1929. In either of the latter patents, entry of the gauge within the bore of the workpiece closes a circuit by which an extended movement of the carriage is procured.

For the purposes oi the present invention, it is sufiicient to note that closing of the circuit by entry of the roughing gauge within the bore of the workpiece procures sliding movement of the left hand reversing dog 11 to the left, thereby permitting the carriage to move to the right beyond the normal reciprocatory position.

Referring first to Fig. 9, which shows the wiring diagram, electric current is supplied by a generator 24, one terminal of which is. connected by a lead 25 to a ground 26 and the other terminal of which is connected by a supply lead 27 to the movable element 28 of a switch 29, the latter being positioned, as shown in Fig. 1, on the front of the machine. The stationary plate or contact 30 of the switch 29 is connected by a lead 31 'to one terminal of the electromagnet 32, the other terminal of said electromagnet being connected by a lead 33 to a gauge contact 34, and the cooperating gauge contact 35 is connected by a lead 36. to a ground 37. Entry of the above noted roughing gauge within the bore of the workpiece which, as above stated, occurs before the workpiece reaches finished size, provides an electrical connection between the

gauge contacts

34 and 35, thereby energizing the electromagnet 32 to procure attraction of an armature member 38 of said elec tromagnet. Attraction of the armature procures elevation of a lever arm 40, which is pivoted on the base of the machine 1 and integral with the armature 38.

Elevation of said lever raises the upper end of said lever into a position to procure longitudinal shifting movement of the dog '11 along the table for the extended movement of the carriage. As shown in Figs. 1, 3 and 5, the left hand table dog 11 which normally limits the right hand movement of the table 1 is carried by a block 41 which is mounted so as to be ca-e pable of sliding freely longitudinally of the dog bar 23. Said block 41, during the normal working reciprocations of the grinding wheel 9, is held in definite spaced relation to a block 42 on the dog bar 23 by a latch lever 43 pivoted on the block 42 with the free right hand end of said lever engaging a notch, not shown, in the block 41. When the lever arm is elevated, the free end of the latch 43 is liftedfrom the notch by the free end of said lever arm, and the dog 11 then moves to the left without actuating the reversing member 13 until the block 41 carrying said dog 11 comes into engagement with the block 42 at which time the backing afforded by the block 42 causes the dog 11 to shift the reversing member 13, the movement of the table is reversed and the grinding wheel 9 is returned to operative position.

During the extended movement of the carriage, a double wheel dressing device 44, Fig. 1, mounted on the base of the machine and carrying spaced adjustable dressing tools 45, the spacing of which corresponds to the spacing of the wheels 9 and 10 on the wheel spindle, is rocked downwardly to position said dressing tools in the path of the Wheels by any suitable mechanism such as that shown in United States Letters Patent No. 1,779,094, granted October 21, 1930, to Heald and Guild. It is sufiicient to note for the purposes of' the present application that a depending lever arm 46, Pg. 9, integral with the armature 38 is connected to a valve member 47, Fig. 10, and. in response to energization of the electromagnet 32, procures shifting movement of said valve member 4'7 to the right away from the normal position shown in Fig. 10.

Referring to Fig. 10, fluid pressure is supplied oy a pump 48 through a conduit 50 to an inlet port 51 in the valve casing 52 for the valve 47, the latter normally closing the port 51. An outlet port 53 in the casing 52 is connected by a pipe .54 to a cylinder 55 in which is mounted a piston 56 suitably connected to the dressing device 44. The casing 52 is also provided with an exhaust port 5'7. When the valve 47 is shifted to the right in response to entry of the roughing gauge within the bore of the workpiece, as above pointed out, fluid under pressure enters the cylinder 55 to rock the dressing tools into operative position.

The circuit through the. electromagnet 32 is broken during the extended movement of the carriage to avoid a repetition of the dressing operation by an arm 58 on the block 42, said arm hanging in a position to engage a portion of the switch 29 to rock said switch for moving the contact 28 out of engagement with the stationary contact 30. Breaking of the circuit through electromagnet 32 releases the armature 38, so that said armature returns to the position of Fig. 9, returning the lever arm 40 to-inoperative position. The shifting of the arm 46 at the same time returns the valve 47 to the position shown in Fig. 10, permitting fluid to exhaust from the cylinder 55, the dressing tools then being returned to the inoperative position of Fig. 1 by any suitable mechanism. The wheels 9 and 10 are thus dressed simultaneously and thus smooth sharp cutting surfaces are provided for each successive abrading operation.

Upon reversal of the carriage at the end of the extended movement and return of the grinding wheel 9 into operative engagement with the workpiece, the dog 11 is restored to normal position in any suitable manner as by the mechanism disclosed in the above cited Guild Patent No.

, shown, of the type shown in the above cited Conradson or Kempton and Gallimore patentsenters the bore of the workpiece to procure axial shifting of the abrading wheels relative to the workpiece to withdraw the wheel 9 from the'workpiece and to position the polishing wheel 10 in operative engagement with the same surface of the workpiece. Referring to Fig. 9, entry of the above noted finish gauge within the bore of the workpiece provides an electrical connection between the

gauge contacts

60 and 61. Contact 60 is connected by a lead 62 to a ground 63, and the contact 61 is connected by

leads

64 and 65 to one terminal of an electromagnet 66, the other terminal of which is connected by a lead 6'7 to the lead 2'7, the latter being connected to one terminal of the generator 24. Connection of the

contacts

60 and 61 thus energizes the electromagnet 66 causing attraction of the armature member 68 and thereby procuring counterclockwise rotation of a depending arm '70 integral with said armature, the latter being pivotally mounted on 7 the front of the machine as shown in Fig. 1.

The lower end of said arm '70 is connected to a valve '71, Fig. 10, by which the position of the reversing

dogs

11 and 12 is varied. Referring to Fig. 10, the valve casing '72 for the valve '71 has an inlet port '73 connected by apipe '74 to the supply pipe50 from the pump 48 and is also provided with spaced exhaust ports '75 and '76. Spaced outlet ports '77 and '78 in the casing '72 are connected by conduits 80 and 81 (represented by pipes 80 and 81 in Fig. 10) to the left and hight hand ends respectively of a cylinder 82, the latter being mounted on the front of the table 1 adjacent the right hand end thereof, as best shown in Fig. 1. With the valve '71 in the normal position shown, fluid under pressure is supplied movement of the dog. bar 23 and similarly the' to the right hand end of the cylinder 82 to support a piston 83 mounted therein adjacent the left hand end of' said cylinder. Upon shifting movement of the valve 71 to the right, however, in response to energization of the electromagnet 66, fluid under pressure is admitted to the left hand end of the cylinder 82, thereby urging the piston 83 and the piston rod 84 connected thereto to the right.

This movement of the piston rod 84 to the right operates to shift the position of the reversing

dogs

11 and 12. Referring to Figs. 3, 5 and 6, the table 1 has secured thereto, on the front edge thereof, a bracket 85 which receives a dovetailed slide 86 formed on the dog bar 23 to provide for sliding movement of the latter longitudinally of the table. Longitudinal movement of the dog bar 23 on the table 1 will shift the position of're-' ciprocation of the carriage by shifting the position of the

dogs

11 and 12. To this end, the piston rod 84 has an elongated threaded portion 87 which engages within a socket provided by a bracket 88 secured to the bar 23, and a clamping nut 90 prevents rotation of said threaded portion 87 to maintain the spacing of the bracket 88 on the bar 23 from the piston 83 on the opposite end of the piston rod.

Longitudinal shifting movement of the bracket 86 in response to the fluid pressure entering opposite ends of the cylinder 82 is limited by spaced pairs of

check nuts

91 and 92 on the threaded portion 87 of the piston rod, the latter being slidable in an opening in a bracket 93 secured to the table 1-. The nuts 91 engage the left hand side of the bracket 93 to limit the right hand nuts92 limit the left hand movement of the dog bar 23, the extent of movement being readily varied by shifting either pair of

nuts

91 or 92 on the threaded portion 87. Thus, as the electro magnet 66 is energized, fluid under pressure is admitted to the left hand end of the cylinder 82 to procure movement to the right of the piston 83 and corresponding movement to the right of the

dogs

11 and 12. This longitudinal shifting of the

dogs

11 and 12 procures axial shifting of the abrading wheels .to withdraw the wheel 9 from the workpiece and position the wheel 10 in engagement with the same surface of the workpiece, as shown in Fig. 4. The wheel 10 is'accordingly reciprocated over the surface of the- 'table, is discontinued at any time during the abrading operation being preferably discontinued just prior to or at the time that the finish gauge, which operates to bring the polishing wheel 10 into engagement with the workpiece, enters the bore of said workpiece. To this end, the ratchet wheel 22 has secured thereto a cam 94 which, in response to the clockwise rotation of the ratchet 22 during the crossfeed movement, is carried beneath the pawl 21, thereby preventing further actuation of the ratchet wheel in response to the movements of the pawl. Said cam is positioned for angular adjustment on said bracket wheel in; any suitable manner to engage beneath'said pawl prior to or at the time that the finish gauge enters the workpiece. A

The axial shifting of the abrading wheels to position the polishing wheel 10 in engagement the left away from the bore of the workpiece, at

the time the polishing wheel 10 is placed in operative position, lay-a mechanism of the type fully disclosed in United States Letters Patent No. 1,830,358, issued November-3, 1931 to Guild and Burns. Referring to Fig. 10, a pipe 95 connects the inlet port of a cylinder 96 to the pipe 80 which latter is normally connected to the exhaust so that a piston 97 in the cylinder 96 is normally at the right hand end of said cylinder. Movement of the piston 97 tosthe left withdraws the gauges axially to the left away from the workpiece through mechanism disclosed in the above cited Guild and Burns Patent No. 1,830,358. This movement of the piston 9'7 is procured in response to shifting movement of the valve 78 to the right which movement, as above stated, establishes fluid connection from the pump 48 to the pipe or connection 80 and accordingly admits fluid under pressure to the right hand end of the cylinder 96 procuring a withdrawal of the gauges from the workpiece. Since the valve '78 remains in its right hand position during the remainder of the abrading operation while the polishing wheel is in operative position, the gauges are held in their spaced inoperative relation during the time that the grinding wheel 9, is in a position to contact with said gauges.

In order to provide a suitable polishing pressure between the polishing wheel and the workpiece, said wheel may be somewhat larger in diameter than the grinding wheel so that, as the polishing wheel is shifted into operative position, the relative position of the cross-slide being unchanged, said polishing wheel engages the surface of the workpiece with a relatively greater pressure than the pressure exerted by the grinding wheel. In order that the polishing wheel may be' somewhat larger than the grinding wheel, the spaced adjustable dressing tools 45, above noted, are arranged so that the vertical plane defined by the point of the dressing tool for the polishing wheel when said tool is in op- 1 erative position is spaced a greater distancefrom the axis of rotation of the workpiece than the vertical plane defined by the dressing tool for the rough grinding or abrading wheeL. By this adjustment of the dressing tools, the polishing wheel will be maintained at all, times at a predetermined greater diameter than the grindingwheel so that at each successive abradingoperation, the relative positions of the cutting surfaces of the abrading wheels is the same.

After the polishing wheel has been shifted into operative engagement with the workpiece, the table 1 is reciprocated to procure a traversing movement of said polishing wheel over the surface of the workpiece, the polishing operation being under the control of a time relay mechanism which is set in operation when .electrical connection between the

gauge contacts

60 and 61 is established to procure axial withdrawal movement of the abrading wheels from the workpiece a predetermined time thereafter. Referring to Fig. 9, the supply lead 27 from the generator 24 is connected by a lead 98 to one terminal of a solenoid 100 and the other terminal of said solenoid is connected by a lead 101 to the lead 64 from the gauge contact 61. Electrical connection of the

gauge contacts

60 and 61 thus energizes the solenoid 100, thereby causing attraction of a switch member 102 to establish electrical connection between

stationary contacts

103 and 104. Contact 104 is connected to a ground 105 by a lead 106 and the contact 103 is connected by a lead 107 to one terminal of a time relay motor 108. The other terminal of said motor is connected by a lead 109 to one blade 110 of a double blade switch 111 and, in the normal position of said switch, the blade 110 is in engagement with a contact 112 which is connected to the lead 27 from the generator 23 by a lead 113. Elevation of the switch member 102 by the solenoid 100. thus establishes a circuit by which the motor 108 is set in operation.

The motor 108 comprises a time relay motor which operates a predetermined time after it is set in operation to rock the switch member 111 and bring a second blade 114 thereof into engagement with a contact 115, the latter being connected by a lead 116 to a ground 117. The

blade 114 is normally connected through a lead 118 to one terminal of an electromagnet 120, the other terminal of which is connected to the lead 27 by a lead 121. Accordingly, a predetermined time after the

gauge contacts

60 and 61 are connected, the electromagnet 120 is energized to cause attraction of an armature member 122 and consequent elevation of a lever arm 123 integral with the armature, said lever arm being pivoted on the front of the machine on the same stud 124 which provides the pivotal support for the lever arm 40.

Elevation of the lever arm 123 raises the upper end thereof into horizontal alinement with the left hand reversing dog 11 which, as shown in Figs. 2 and 4, is pivotally mounted on the block 41. With the lever arm 123 in raised position,

the dog 11 is elevated thereby during movement of the carriage to the right and passes over the reversing lever 13 without rocking said lever so that the carriage continuesbeyond its. normal reciprocating position to the rest position shown in Fig. 1 where it is brought to rest in the manner disclosed in the above cited patent to Heald, et al. No. 1,582,468.

When the run-out of the carriage to rest position is initiated by the elevation of the lever arm 123, the polishing wheel is withdrawn radially from contact with the workpiece to avoid scratch lines on the polished surface. The back-off mechanism for the radial withdrawal movement is similar to that disclosed in United States Letters Patent No. 1,816,082,-issued July 28, 1931 to Heald and Guild. This mechanism is not of itself the invention in the present case; it is suflicient to note that as the lever arm 123 is elevated, a depending lever arm 125 integral therewith procures shifting movement of a valve 126 to which said depending arm is connected for actuating the mechanism by which the wheel is radially withdrawn from the workpiece. Referring to Fig. 10, the valve casing 127 for the valve 126 has an inlet port 128 connected by a pipe 130 to the supply pipe 50. The casing also has an outlet port 131 connected by a pipe 132 to a cylinder 133 on the back of the machine, as shown in Figs. 7 and 8, and an exhaust port 134. The valve 126, which is normally in the position shown in Fig. 10, closes theinlet port 128 to prevent entry of fluid under pressure into the cylinder 133. Upon shifting movement of. the valve 126, however, in response to movement of the arm 125, fluid connection is provided between the port 128 and the outlet port 131, and fluid under pressure is admitted to the cylinder 133.

I Referring now to Figs. 7 and 8, the crossfeed shaft 15 adjacent the rearward end thereof carries a pair of spaced ball bearing members 135 which are supported against movement on said shaft. The outer races of said ball bearing members support a sleeve 136 for rotation about the crossfeed shaft and prevent axial movement of the sleeve 136 on said shaft, and the outer surface of said sleeve is threaded'to engage in a threaded portion 137 of the table 1. So long as the member 136 is supported against rotation, the shaft 15 is held against axial movement; rotation of said member 136, however, will procure axial shifting of the crossfeed shaft 15 which will accordingly shift the cross-slide 14 and withdraw the polishing wheel radially from the work. To procure rotation of the sleeve 136, a substantially annular member 138 is secured thereto and is provided with an am 140; the latter carries a roller 141 which, during the normal reciprocations of the carriage, moves back and forth in a horizontal path directly above a horizontal bar 142. Said bar 142 is pivotally connected to a pair of links 143 and 144 which are pivotally mounted on the machine frame on

studs

145 and 146, the spacing of said studs corresponding to the spacing of the pivotal connections of the links with the bar 142. The link 144 has an arm 147 provided with a roller. 148 which is located above and engages with the upper surface of a piston 150 slidable in the cylinder 133. Move-,

tion of the link 141 and accordingly the vertical movement of the bar 142.

The sleeve 136 is normally maintained in the position shown in Figs. 7 and 8 by a spring 153, one end of which engages a pin 154 on the carriage 1 andthe other end of which engages a pin 155 on a cap 156 secured to the rearward end of the annular member 138. The counterclockwise rotation of the cap 156 in response to the pull of the spring 153 is limited by a projecting portion 157 on the member 136, said projecting portio engaging a surface 158 on the table 1.

' During the run-out of the carriage to rest position, the shifting dog bar 23 is restored to the original position. Referring to Figs. 1 and 3, the bracket 88 has secured thereto a horizontal extending bar 160 which is in alinement with and in a position to rock a lever arm 161 counterclockwise as the carriage moves to the right. The arm 161 is integral with the depending arm 70 which controls the valve 71 shifting said valve to the left into the position of Fig. 10 to establish fluid connection between the pump 48 and the right hand end of the cylinder 82, thereby actuating the piston 83 to the left to shift the dog bar 23 and the reversing dogs carried thereon to the left into the position of Fig. 1, the movement of said dog bar in this direction being limited, as above stated, by the check nuts 92 on the piston rod.

The operation of the machine which will be and assuming. that an unground workpiece has been placed in the work supporting member 8, the machine is set in operation by movement of a manual reversing lever 162 to the left from the position of Fig. v.l, thereby procuring movement of the-table 1 to the left to bring the grinding wheel 9 into operative engagement with the surface of thevworkpiece. During this movement of the carriage to the left, an arm 163 carried by the block 42 and normally hanging in the position shown in Figs. 1 and 9 engages a projecting portion of the movable member 28 of the switch 29 to reposition said switch in engagement with the stationary contact or switch portion 30 in readiness for the subsequent energization of the mag-' net 32 in response to entry of the roughing gauge within the bore of the workpiece. As the wheel 9 enters the bore of the workpiece, the reversing dog 11 passes over the end of the reversing lever 13 and the carriage is then reciprocated with the grinding wheel 9 in operative position by alternate shifting movement of the reversing lever 13 by the

dogs

11 and 12. This reciprocation continues until the roughing gauge enters the work and establishes an electrical circuit through the electromagnet 32 elevating the lever arm 40 to procure the extended movement of the carriage to the right. During this extended movement, the dressing tools are rocked downwardly into operative position for the dressing operation and the carriage is then reciprocated to return the grinding wheel 9 into engagement of the work, the dressing tools being moved back into inoperative position and the dog "llbeing returned to normal position. The grinding operation then continues further with the grinding wheel 9 in operative engagement with the same surface of the workpiece until the finish gauge enters the workpiece indicating that the work is substantially at the desired size. Entry of the finish gauge within the workpiece energizes the electromagnet 66, shifting the valve 71 to procure movement of the sliding dog bar 23 to the right, and thereby shifting the position of reciprocation of the abrading wheels to bring the polishing wheel 10 into operative engagement with the same surface of the workpiece.

The crossfeed movement which, prior to this time, has caused a radial feeding movement of the grinding wheel 9 against the surface of the workpiece having now been discontinued by the cam 94, the polishing wheel 10 operates, without a cross-feed movement imparted thereto, for a predetermined time subsequent to the entry of the finished gauge within the work as determined by the adjustment of the time relay mechanism above described, the latter being set in operation by entry of the roughing gauge within the bore of the workpiece. After a predetermined time interval, the time relay motor 108 energizes the electromagnet 120 which procures a radial withdrawal movement of the polishing wheel 10 away from the surface of the workpiece and an axial withdrawal movement of the polishing wheel by a run-out of the carriage to rest position. It will be obvious that the stock removal by the polishing wheel 10 is so small as to be negligible, or in certain cases the small amount of stock removal by the polishing wheel 10 which brings the workpiece to the desired size may be provided for by allowing the finish gauge to enter the bore of the workpiece slightly before the workpiece is at the desired size.

From the foregoing, it will be apparent that the present invention provides for a machine which, while a workpiece is mounted in and rotated by a work support, will procure first a grinding operation upon a surface of the workpiece and thereafter will procure a polishing operation on the same surface of the workpiece while said workpiece is mounted in and rotated by the same workholding member. The grinding wheel 9 which performs the grinding operation on the workpiece is arranged -to operate first for a rough grinding on said workpiece and thereafter for a finish grinding, which latter provides a relatively smooth surface requiring very little polishing by the polishing wheel to provide a suitable polished surface. Each of the separate abrading wheels is reciprocated over the surface of the workpiece and the position of reciprocation to maintain either wheel in operative position is determined by stop members on the reciprocatory carriage of the machine. The position of reciprocation is shifted to withdraw the operative wheel out of operative position and position the other wheel" in operative position for a cutting operation by the other wheel, this shifting of the reciprocatory position being procured by shifting said stop members longitudinally along the carriage. Shifting of the stop members is preferably procured by fluid under pressure.

Although in the above specification, the rough grinding and finishing operations and the polish,- ing operations have been separately described, it will be noted that the machine once having been set in operation, it continues through a complete cycle without coming to rest, the complete cycle including both the grinding and the polishing operations. Thus the abrading operation of the machine when considered as referring to the automatic cycle of the machine includes both the grinding and polishing by the. separate wheels.

Iclaim,

i. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, stops on said carriage for engagement with said element to actuate said element, and means to shift said stops longitudinally along said carriage to shift the position of reciprocation of the carriage 21 In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, stops on said carriage for engagement with said element to actuate said element, and means actuated in response to the carriage movement to shift said stops along said carriage to shift the position of reciprocation of the carriage.

3. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, a pair of stops on said carriage for engagement with said reversing element, and means to shift said pair of stops as a unit along said carriage to shift the position of reciprocation of the carriage.

4. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, a pair of stops on said carriage for engagement with said reversing element, and means responsive to the carriage movement to shift said pair of stops as a unit along said carriageto shift the position of reciprocation of the carriage.

5.. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, a pair of stops on said carriage for engagement with said reversing element, said pair of stops being movable as a unit along said carriage.

6. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, a pair of stops relatively adjustable toward and away from each other, said stops being arranged to engage and actuate said element, and means to shift said pair of stops as a unit along said table.

7. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, and means governed by the progress of theabrading operation to. shift said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece.

8. In an abrading machine, a work supporting member and a wheel supportingmember, a carriage on which one of said members is mounted, a

plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one-of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including a pair of stops on said carriage, and means governed by the progress of the abrading operation to shift said pair of stops as a unit along said carriage to position a second of said abrading wheels in operative engagement with the same surface of the workpiece.

9. m an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including a pair of stops on said carriage relatively adjustable toward and away from each other, and means to shift said pair of stops as a unit along said carriage to position a second of said abrading wheels in engagement with the same surface of the workpiece.

10. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops *on said carriage, means governed by the progress of the abrading operation to shift said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece, and'means to return said stops to original position.

11. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members ismounted, a plurality of abrading wheels carried by said wheelsupporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including a pair of stops on said carriage, means governed by the progress of the abrading operation to shift said pair of stops as a unit along said carriage to position a second of said abrading wheels in operative engagement with the same surface of the workpiece, and means responsive to the carriage movement to return said stops to original position.

12. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including a pair of stops on said carriage relatively adjustable toward and away from each other, means to shift said pair of dogs as a unit along said carriage to position a second of said abrading wheels in engagement with the same surface of the workpiece, and means responsive to the carriage movement to return said stops to original position.

13. In an abrading machine, a work supporting member and a wheel supporting member, a carriage upon one of which. said members is mounted, a grinding wheel and a polishing wheel axially spaced on said wheel supporting member, means to procure reciprocation of the carriage to obtain a longitudinal traverse of the grinding wheel over a surface of a workpiece mounted in and rotated by said work supporting member, and means governed by the progress of the grinding operation to shift the position of reciprocation of said carriage to position the polishing wheel in operative engagement with the same surface of the workpiece.

14. In an abrading machine, a work supporting member and a wheel supporting member, a carriage upon one of which said members is mounted, a grinding wheel and a polishing wheel axially spaced on said wheel supporting member, means to procure reciprocation of the carriage to obtain a longitudinal traverse of the grinding wheel over a surface of a workpiece mounted in and rotated by said work supporting member,

means governed by the progress of the grinding operation to shift the position of reciprocation of said carriage to position the polishing wheel in operative engagement with the same surface of the workpiece, and means to procure separation of said wheels from the workpiece at the end of the abrading operation.

15. In an abrading machine, a work supporting member and a wheel supporting member, a carriage upon one of which said members is mounted, a grinding wheel and a polishing wheel axially spaced on said wheel supporting member, means to procure a transverse movement between said members, means to procure reciprocation of the carriage to obtain a longitudinal traverse of the grinding wheel over a surface of a workpiece mounted in and rotated by said work supporting member, means governed by the progress of the grinding operation to shift the position of reciprocation of said carriage to position the polishing wheel in operative engagement with the same surface of the workpiece,

16. In apparatus of the class described, a re ciprocatory carriage, a reversing element to reverse the direction of movement of said carriage, stops on said carriage for engagement with said element to actuate said element, and fluid pressure means to shift said stops longitudinally along said carriage to shift the position of reciprocation of the carriage.

1'7. In apparatus of the class described, a reciprocatory carriage, a reversing element to reverse the direction of movement of said carriage. stops on said carriage for engagement with said element to actuate said element, and fluid pressure means actuated in response to the carriage movement to shift said stops along said carriage to shift the position of reciprocation of the carriage.

18. In apparatus of the class described, a reciprocatory carriage, a reversing element to re.- verse the direction of movement of said carriage, a pair of stops on said carriage for engagement with said reversing element, and fluid pressure means to shift said pair of stops as a unit along said carriage to shift. the position of reciprocation of the carriage.

19. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation ofsaid carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, and fluid pressure means governed by the progress ofthe abrading operation to shift said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece.

20. Inan abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure re-,

ciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member,

said means including a pair of stops on said carriage, and fluid pressure means governed by the progress of the abrading operation to shift said pair of stops as a unit along said carriage to position a second of said abrading wheels in operative engagement with the same surface of the workpiece.

' 21. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, a gage member adapted to enter the workresponsive to the exte resents piece when the latter reaches a predetermined size, and means responsive to the entry of said. gage within the workpiece for shifting said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece.

22. in an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, a gage member adapted to enter the workpiece when the latter reaches a predetermined size, and fluid pressure means responsive to the entry of said gage within the workpiece for shifting said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece.

23. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to' procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, a gage member adapted to enter the workpiece when the latter reaches a predetermined size, means responsive to the entry of said gage within the workpiece for shifting said stops along said carriage to position a second of said abrading wheels in operative engagement with the workpiece, and means operative upon shifting of the wheels for retracting the gage from the workpiece.

24. In apparatus of the class described, a reciprocatory carriage, a reversing element to re- .verse the direction of movement of said carriage, a pair of stops on said carriage for engagement with said reversing element, means to procure an extended movement of said carriage, and means ded movement for shifting the position of said stops as a unit longitudinally of the carriage. I

25. In an abrading machine, a work supporting member and a wheel supporting member, a carriage on which one of said members is mounted, a plurality of abrading wheels carried by said wheel supporting member, means to procure reciprocation of said carriage in one position with one of said abrading wheels in operative relation to a workpiece in said work supporting member, said means including stops on said carriage, means for procuring an extended movement of said carriage, and means responsive to said extended movement for shifting said stops longitudinally along said carriage.

DWIGHT C. PAGE.