US1980682A - Grinding machine - Google Patents

Description

Nov. 13, 1934. R, E. w. HARRISON 1,980,682

GRINDING MACHINE Filed Aug. 10, 1951 6 Sheets-Sheet 1 I I I WM I:4a Gttorneg Nov. 13, 1934.

R. E. W. HARRlSON GRINDING MACHINE Filed Aug. 10, 1551 6 Sheets-Sheet 2 Nov. 13, 1934.

R. E. w. HARRISON GRINDING MACHINE Filed Aug. 10, 1951 B'Sheets-Sheet 3 Summer wizP/fl/Amwa/y Cittorneg Nov. 13, 1934.

R. E. W. HARRISON GRINDING MACHINE Filed Aug. 10, 1931 6 Sheets-Sheet 4 (Ittorneg R. E. w. HARRISON 1,980,682

GRINDING MACHINE Filed Aug. 10, 1931 6 Sheets-Sheet 5 Nov. 13, 1934.

Bnventor Gttcmeg Nov. 13, 1934. R. E. w. HARRISON I 1,980,682

GRINDING MACHINE Filed Aug. 10, 1931 6 Sheets-Sheet 6 lq: J0

(Ittcrneg Patented Nov. 13, 1934 PATENT! OFFICE GRINDING MACHINE Robert E. W. Harrison, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application August 10,

6 Claims.

This invention relates to improvements in grinding machines, and especially to improvements in the position and arrangement of controls therefor.

An object of the invention is the provision of a grinding machine arranged to be operated and controlled from a plurality of stations.

Another object of this invention is the provision of an improved grinding machine so constructed and arranged that the action of the grinding wheel on the work can be observed by the operator without the use of platforms, mirrors or the like, as has been the practice in the past.

A further object of the invention is the provision of an improved grinding machine in which the various adjustments of the parts thereof can be made in the most expeditious manner, and while the operator is positioned directly adjacent the grinding wheel and observing the actual relative positions of the parts without the use of extraneous appliances.

A still further object of the invention is the provision of a grinding machine having front and rear controls therefor and having said controls so interconnected that either may be employed without reference to the other for obtaining the desired movement of the parts of the machine.

Other objects and advantages of the present invention should be readily apparent by-reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

In the drawings:

Figure 1 is a front elevation of a grinding machine embodying the improvements of this invention.

Figure 2 is a top plan view of the machineshown in Figure 1.

Figure 3 is a sectional view taken on line 33 of Figure 1.

Figure 4 is a sectional View taken on line 4-4 of Figure 1.

Figure 5 is a sectional view taken on' line 5-5 of Figure 4.

Figure 6 is a sectional view taken on line 66 of Figure 4.

Figure '7 is a sectional view taken on line 7-7 of Figure 2.

1931, Serial No. 556,124 (or. 51-95) Figure 8 is a sectional view taken on line 8-8 of Figure 1. v

Figure- 9 is a wiring diagram of certain interconnected parts forming a detail of the invention. Y v .60

Figure 10 is an elevational view of the control handles and members from the rear control station.

Figure 11 is a sectional view taken on line 11-11. of Figure 4.

Figure 12 is a view showing the controls for actuating the grinding Wheel carriage as seen particularly from line 1212 on Figures 3 and. 7.

Throughout the several views of the drawings similar reference characters are employed to denote the same or similar parts.

Heretoiore in the use of center type grinders. difficulty has been experienced in obtaining the proper view of the action of the grinding wheel on the work from the normalpositionv at the front of the machine. This is especiallyvtruein the case oflarge diameter work, such as rolls used in rolling mills, paper mills, or the like, where the work is between the operator and. the grinding wheel and the grinding, wheel contacts with the work at a point diametrically opposite from the operator.

In the attempt to overcome this difliculty, mirrors have been mounted insuch a position as to reflect to the operator the condition that exists at the point of engagement between thegrinding wheel and work, or benches or platforms have been built at the forward station of the machine to elevate. the operator so, that he may look over the work and observe conditions at the actual pointof grinding. The first method was not satisfactory because-spray from the coolant would cloudthe mirror so that a clear view could not behad, or the burning of the particles of metal removed by the wheel set up such a. glare that again clear vision could not be had. With-the platform. or bench ar-. rangement, continual danger to the operator existed in thathis clothes or wearing apparel might be caught by the rotating work piece, thereby resulting in injury to himself.

By the present arrangement, a grinding machine can be successfully and conveniently controlled from either the normal forward station while operating on comparatively 'small diam eter work, or alternatively controlled from a point or a station directly adjacent the grinding wheel at the rear of the machine.

A device embodying this invention may comprise a bed or support 15 having formed on the cent ends of the work 24. Extending laterally of the bed 15 from its rear face is the extension 25 having formed on its upper surface guideways 26 for the grinding wheel carriage 27. A spindle 28 is journaled in the carriage 27 and has secured to its one end for movement therewith the grinding wheel 29 adapted to operate upon the work 24. The work slide 18 is actuated longitudinally of the bed 15 to traverse the work past the grinding wheel, and the carriage 27. is likewise shiftable on the Ways 26 toward the work 24 to eifect a feeding movement between the work and wheel. The means for actuating these members will be" described in detail later.

The means for feeding the grinding wheel carriage,illustratedin Figures 1, 3 and 7,36% prises-"a screw 30 having its threaded end 31 received in a nut 32 fastened to a web 33 that depends interiorly of the carriage 27; The screw 30 has a reduced portion 34 extending beyond the carriage 2'7, and journaled in bearing 35 carried by housing or' bracket 36 secured by any desirable means to the rear of the bed extension 25.; A gear- 37 issecured tothe re duced end 34"of'the"screw 35 and enclosed within the housing 36. The gear 37 meshes with a pinion 38 of a compound gear 39 rotatably 35' e or bracket 36.

journaled on a stud 40 carried by the housing The gear 41 ofthe compound gear 39 meshes with a pinion 42 on the outer end of a feed shaft 43 which extends transversely 1 of the bed and is journaled at its opposite ends in bearing 44 supported by the bracket 36 and bearing 45 supported by a housing 46 secured to the forward end of the bed 15. The shaft 43 is adapted: to be rotated either continuously by a hand crank 47 or intermittently by the pick feed method through a ratchet 48, as is customary with grinding machines of this type.

The hand crank 47 and ratchet 48 are connected througha suitable transmission indicated generally by the numeral 50 with a gear 51 on the forward end of the shaft 43 and enclosed within the housing 46. It is believed that a detail description of the feeding mechanism is unnecessary since that disclosed in Figure 3 is one of aiusual and well known structure.

The shaft 43 has secured to it near its forward end a sprocket 52 about which silent chain 53 extends. This sprocket chain 53 is further trained about a sprocket 54 pinned or otherwise secured to a'stub shaft 55 fastened to a shaft'56 journaled in housing 57 secured to the rear face of the bed or base 15. .The shaft 56 has integral with or secured thereto a gea'r58 meshing with idler gears 59 in turn meshing with a gear 60 rotatably mounted on a sleeve 61 held in the bracket or support 57. The gear 60 has extending therefrom a sleeve 62 onwhich is formed a gear 63 meshing with. pinion 64 which is .a part of a suitable train of gears .65

' terminating in pinion 66 integral with or secured to the shaft-67 mounted interiorly of the sleeve 61. The transmission gears 64, and 66 are of the planetary type'and are carried by a sleeve or flange 68 journaled in the bracket 57 and to which is secured a ratchet wheel 69 similar to the ratchet wheel 48 of the normal feed mechanism. Couplable with the ratchet wheel 69 as by spring pressed plunger 70 is a manually actuable hand wheel 71 for rotating the ratchet 69 at a rapid rate. The ratchet 69 is further adapted to be intermittently actuated by the pick feed method, which includes the pawl 72 operable as will later appear.

From the foregoing description it will be noted'that the shaft 43 may be driven or fed from a point in front of the bed or base 15 through the hand crank 47 and ratchet 48, or

from the rear of said bed. or base 15 by the hand input power to either of these mechanisms is carried to the screw 30 for operating same.

"The screw 30 is intermittently rotated for feeding the grinding wheel toward the work at each end of the reoiprocable stroke of the table 18. The table is driven from the main motor 720 m'ountedin' the rear of the machine and having its motor shaft 73 coupled to countershaft 74 as by coupling 75. As shown in Figure 2;" the countershaft 74 is geared through chain 76 with the jack shaft 77 which has on its other end the'driving pinion78. The'pinion 78 meshes with a gear 79 to which is pinned or otherwise secured clutch member 80 having connections as at 81 with friction disc 82 of the multiple disc or plate clutch indicated generally by the numeral 83. Contacting with the disc 81 on opposite sides thereof are friction discs 84 associated with the clutch member 85. A clamp plate 86-contacts with the outer surface of the disc 84 and is adapted to compress the friction discs 82 and 84 toward one another through the agency of crank 87 pivoted to member 88. The crank 87 is adapted to be oscillated about its pivot by an actuator 89 on" the 'end of sliding clutch rod 90 which is slidably keyed or pinned as at 91 to the upper change speed shaft 92 to which the clutch member 85 is keyed. The upper shaft 92 has a splined portion 93 slidable on which is the gear cone 94 adapted to have its individual gears meshed with; the individual gears of cone 95 secured to the lower driven shaft 96. This shaft 96 has on the splined portion 97 thereof a slidable gear cone 98 whose individual gears mesh with the individual gears of gear cone 99 secured to the upper shaft 93. The dual control mechanism for shifting these gears will be described in detail later.

The lower driven shaft 96 is the final'shaft and terminates in abevel gear 100 meshing with J a similar gear 101 on the inner end of transverse shaft 102. This shaft 102 extends. to the front of the machine Where it carries a bevel gear 103 meshing with a second bevel gear 104 on a sleeve 105. The sleeve 105 is adapted to be di rectly connected with a shaft 106, or through a back gear 106a contained'in back gear housing 107, the desirable connection being made through the agency of a lever 108 pivoted on the front of the machine, as seen in Figure 1. The shaft 106, see Figure 8, extends along the front of the machine interiorly of the bed and is journaled in sleeves 109 and 110 secured in a bracket 111 secured to the front of the machine. The bushings 109 and 110 form journals respectively for bevel pinions 112 and 113. The opposed faces of the gears 112 and 113 are each provided with a clutch 114 cooperating with double faced clutch 115 slidably keyed at 116 to the shaft 106. The clutch spool 115 receives a shifter fork 117 slidably mounted on a shaft 118 associated with the bracket 111. Thepinions 112 and 113 are simultaneously in mesh with a bevel gear 119' secured to one end of a shaft 120, which shaft is in turn connected by safety clutch 121 with a worm shaft 122, having integral therewith the worm 123.

The clutch 115 and gears 112 and 113 constitute a reversing mechanism whereby the worm 123 is adapted to be rotated in opposite directions. The worm 123 meshes with worm wheel 124 loosely journaled on a vertical shaft 125, see Figure 3. The vertical shaft 125 has slidably splined thereon a clutch 126 cooperating with a clutch associated with the worm wheel 124, and a second clutch associated with a bevel gear 127. The clutch 126 is adapted to be shifted by a suitable clutch shifter received in a circumferential groove formed therein which shifter is carried by a shaft 126a; and operated by a lever 12% on the outer end of shaft 126a. Assuming the clutch 126 to be engaged with the worm wheel clutch, rotation of the worm wheel will effect longitudinal reciprocation of the table 18 through the interconnection of rack pinion 128 on the end of shaft 125, and the rack 129 secured to the table 18. If, however, the clutch 126 is connected with the bevel gear clutch, the table may be reciprocated manually through the hand wheel 129d which through a suitable gear train operates a shaft 12% having thereon the pinion 1290 enmeshed with the gear 127 for rotating same and shaft 125 and pinion 128.

The traverse of the table is automatically reversed at each end of its movement, for which purpose it has secured thereto dogs 139 and 131 cooperating with a projection on reverse lever 132. This lever is secured at its lower end to the usual load and fire reversing mechanism 133 for shifting the clutch shifter fork 117 for engagement with either of the pinions 112 or 113. Secured to the lever 132 intermediate its ends is an arm 134 having a cam faced nose 135 engaging a roller 136 carried by bell crank lever 137. The bell crank 137 is pivoted at 138 to a bracket carried by the machine, and the free end of one.

arm thereof has a pin and slot connection at 139 with a plunger 140. The plunger 140 is mounted in a socket, and has there-beneath a spring 141 tending to at all times raise the plunger 140.

Extending from the upper end of the plunger is a rod 142 coupled to bell crank 143 pivoted about the axis of ratchet 48, and which bell crank carries at the end of its other arm the pawl 144 for engagement with the ratchet 48 and operating the screw 30 through the mechanism above described. From the foregoing it will be noted that the grinding wheel carriage is fed at each reversal of the table 18 through the cam 135 on the arm 134, depressing the bell crank 137 to adjust the pawl 144 relative to the ratchet 48. As the point of the cam 135 passes the roller 136, the spring 141 actuates the bell crank 143 in the opposite direction, thereby setting the ratchet and parts fo the next infeed by the cam 135.

The foregoing pick feed is the operation from the front of the machine, where the dogs 131 are adapted to operate the reversing lever. The said dogs 130 and 131 are employed whether feeding from the front operating station through the ratchet 48, or from the rear station and operating through the ratchet 69. In the latter case, however, the pawl 144 is actuated about its pivot 145 so as to be free of any engagement with the ratchet" 48. At this. time a. link 1'46 pivoted at 147 to the reversing lever 132 is employed and operates through a crank 148 secured to its free end for oscillating shaft 149. This shaft 149 extends through the bed or support 15 to the rear thereof terminating within a casing or housing 150. Enclosed. within the housing 150 and secured to the end of the shaft 149 is an arm 151 having a cam shaped nose 152 similar to the arm 134. This nose 152 similarly cooperates with a roller'153 carried by one arm of bellcrank 154 pivoted at 155 interiorly of the housing 15 The free end of the second arm of the bell crank 154 has a pin and slot connection 155 with a plunger 157 similar to the plunger 140. This plunger is operated through the cooperation of the cam nose 152v and roller 153 in one direction against the resistance of a spring 158' secured at one end to the arm 154 and at its other end to the bed. The other end of the plunger 157 has extending therefrom arod 159 for operating a 1 bell crank 160 to which the pawl 72 is pivotally secured. As the pawl oscillates back and forth through the reciprocation of the plunger 157, the ratchet 69 is intermittently advanced forrotating the sprocket 54, which through the chain 53 rotates the transverse shaft 43 and the screw 30:

From the foregoing it will be noted that the cross-feed'screw 30 may be manually actuated from either the front or the rear of the machine; Also, it will be noted that the pick feed mechanism may be employed from either the front or the rear of the machine for'intermittently, feeding the grinding Wheel and work relative to one another. It should be noted, however, that when the pawl 72 is employed, the pawl 144 must be disengaged, and vice versa, when the pawl 144 isbeing used for operating the cross-feed mechanism the pawl 72 must be disengaged. It

will also be seen that the operator has complete control of the feeding of the grinding wheel carriage whether he be positioned in the front normal station or at the rear supplementary station.

In order to initiate or stop traversing of the table, it is necessary to engage and disengage the main friction clutch 83 above referred to.. This clutch, as noted above, is engaged and disengaged by the cone shaped actuator 89 which is' on the end of clutch shifter rod 90. The'inner end of the rod 90 has secured thereto through the pin 91 a clutch spool 161 slidable on the exterior of the upper drive shaft 92; A shifter fork 1'62 pivoted at 163 to a bracket 164 extending from change gear case 165 is employed for.

shifting the said clutch spool 181. For this purpose the shifter 162 has its lower end received in a circumferential groove 165 formed in the shifter spool and has pivoted to its upper end at 167 a link 168 having its other end pivoted 163 to a crank 170. The crank 170 is carried by a shaft 171 which extends transversely of the bed beyond the front face thereof. To the projecting end of the shaft 171 is a lever 172, whereby the said shaft may be oscillated for connecting and disconnecting the clutch 83. This lever 172 is in position to control the machine when the operator is in the front operating station. As shown in Figures 2 and 10, the shaft 171 has secured to it intermediate its ends a second lever 173, whereby the shaft may be oscillated and the reciprocation of the table started and stopped from the rear operating station.

As was noted above the speed of reciprocation of the table may be varied by shifting the tical shaft 204.

gear cones 94 and 98 relative'to' the shafts 92 and 97 for meshing same with complementary gear cones 95 and 99. For this purpose the gear cones 94 and 98 are eachprovided with a circumferential groove 1'74 and 175 respectively. Clutch shifter forks 176 and 177 are received in the said grooves and are each respectively secured to one end of shafts 1'78 and 1'79. The shaft 178 is slidable through a bore 180- in the gear case or housing 165 as well as through a bearinglug 181 depending from the gear case 165. This shaft 178 is further provided on its under surface near the end opposite to the shifter fork 176 with rack teeth 182 adapted to mesh with segmental gear 183. The. shifter rod 179 is likewise mounted for sliding movement through a bore 184 in the gear case 165, and is also provided'with rack teeth 185 likewise adapted to mesh with the segmental gear 183. As shown in Figure 4 the segmental gear 183 is secured to the end of a stub shaft 186 which is connected through universal joint 187 with link 188. The link 188 is in turn connected through universal joint 189 with the gear shifter rod 190. it will be'noted that the shifter rod 190 extends through the bed or support 15 to the forward face thereof, and has secured to said forward end the bevel pinion 191. The pinion 191 is enclosed within a housing 192 and meshes with. a pinion 193 on the lower end of vertical shaft 194. This shaft 194 is journaled in the housing 192 and is provided on its upper'end with a bevel gear 195 meshing with a complementary gear 196 on shaft 197 likewise journaled in the bracket 192 and carrying on its forward end a lever 198. A spring pressed plunger 199 on the end of the lever 198, cooperates with a notched index plate 200 secured to the housing 192 and indicates the particular gear engagement of the several gear cones 94, 95, 98 and 99.

From the foregoing it will be noted that the gear cones 94 and 98 may be axially shifted through the manipulation of the lever 198 from the forward or normal control station. This shifting is accomplished by oscillating the lever 198 through 180 degrees in one direction and then through 180 degrees in the opposite direction for in the first instance shifting the gear'oone 94 and subsequently shifting the gear cone 98.

As seen in Figure 4 the shaft 190 also extends through the housing 201 secured to the rear face of the bed 15.

The shaft 190 within the housing 201 has secured to a reduced portion thereof the bevel gear 202 meshing with a complementary gear 203 on the lower end of ver- The vertical shaft 204 is journaled in the housing 201 and has secured to its upper end a bevel gear 205 meshing with a similar bevel gear 206 on shaft 207 journaled in the housing 201 and carrying at its forward end a lever 208. This lever 208 supports a spring pressed plunger 209 cooperating with an index plate 210 secured to the housing 201. The index plate 210 is similar to the index plate 200 and each has indices thereon corresponding one with the other. The plunger is formed in such a way that but a frictional connection exists between it and the notches, so that either lever 198 or 208 may be shifted, which will automatically shift the remaining lever to the same position that the one doing the shifting is positioned. From this it will be seen that the By reference to Figure 4.

plates will each and at all times indicate the existing gear connection, and that either may be operated without consulting the. other for effecting a change gear connection. It will also be noted that the speed of the table may be varied from the rear operating station as well as the forward station as above described.

The headstock illustrated in the drawings is of the self-contained, type and includes the variable speed motor 211 connected through suitable gear chain and gear connections with the spindle for rotatingthe driving dog 212 which extends from the face plate of the headstock. The work is adapted to be rotated at various speeds by varying the speed of the variable speed motor 211, which is accomplished through a rheostat 213 mounted on the forward face of'thejbed 15. The electrical connection betweena rheostat and a variable speed motor is well known and has not been shown in detail in the drawings but reference may be had to the wiring diagram illustrated in Figure9. This diagram illustrates the main leads 214 and 215 from which the motor leads 216 and 217 extend. The lead 216 is wired into the rheostat 213 from which the wire 218 is taken off to the motor 211, being broken by a double pole double throw switch 219. The wire 218 continues from the switch as 220 to the motor 211, while'the return motor line21'7 is. completed between the switch and motor by the wire ,221. From the foregoing, and supposingthe switch blade to be contacting the upper switch contacts as seen in Figure 9, the flow of the current will be through the positive main lead 214, branch 216, rheostat 213, wire 218, switch 219, wire 220 to the motor 211. The flow continues from the motor 211 through the wire 221, to the switch 219, to the wire 217, to the negative main lead In order that the motor may be operated from the rear station, a second rheostat 222 is mounted on the rear face of the bed. This rheostat is connected in the electrical circuit, as seen in Figure 9, by a branch lead 223 extending from the main positive cable 214. A wire 224 extends from the rheostat 222 to one of the lower poles of the switch 219, which if thrown to connect said poles will cause the current to flow into wire 220 and follow the same path as above outlined. The flow from the motor will be the same as above described down to the switch 219 at which time the current will be shunted into 1ine'225 which extends to the main negative lead 215.

From the foregoing description .it' will be noted that the switch 219 must be thrown to connect one or the other pair of its poles with the main electrical leads depending upon whether the headstock motor 211 is to be operated from the forward or rear operating station. It will be noted, however, that the speed of the headstock motor may be controlled as desired from either'the forward or the rear operating stations.

It is believed that the invention will be th'or-.

oughly understood from the foregoing description, and that it will be noted that all movements of the several operating parts are con-- trolled with equal facility from the normal forward operating station as well as from a supplemental station or a station in the rear'of the work supporting table. By this construction all the hitherto known disadvantages of grinding large diameter rolls have been eliminated and the operator may assume a position where he has full unobstructed vision of the conditions existing between the grinding wheel or tool and the work, and can instantly stop further operation of the machine in the event of danger to either the work or the machine, or can modify the feed of the parts in the event of a too heavy a feed existing at the moment. He can readily change the feed by increasing it from the rear station, thereby expediting the production without in anywise endangering the parts, due to the uncertainty of conditions at the actual point of contact between the work and wheel as was the case in the past.

What is claimed is:

1. In a grinding machine the combination of a bed, a slide carried thereby and movable relative thereto, a grinding wheel carried by the slide, means for actuating the slide including an adjusting screw, a plurality of control stations for operating the screw, each control station including a manually operable hand wheel, and a mechanical pick feed mechanism.

2. In a grinding machine the combination of a bed, a slide carried thereby and movable relative thereto, a grinding wheel carried by the slide, means for actuating the slide including an adjusting screw, a plurality of control stations for operating the screw, each control station including a manually operable hand wheel, and a mechanical pick feed mechanism, and means connecting the said control stations whereby operation from either station will supplement the adjustment of the slide from the other station.

3. In a grinding machine the combination of a bed, a slide carried thereby and having a grinding wheel rotatably journaled thereon, means for actuating the slide relative to the bed including an adjusting screw, a transverse shaft, transmission gearing between the shaft and screw, means connected to the shaft for operating same intermittently and continuously, a stub shaft, means for continuously and intermittently actuating the stub shaft, and means connecting the stub shaft with the transverse shaft whereby the latter may partake of the movements of the former.

4. In a grinding machine the combination of a bed, a slide carried thereby and having a grinding wheel rotatably journaled thereon, means for actuating the slide relative to the bed including an adjusting screw, a transverse shaft, transmission gearing between the shaft and screw, means connected to the shaft for operating same intermittently and continuously, a stub shaft, means for continuously and intermittently actuating the stub shaft, means connecting the stub shaft with the transverse shaft whereby the latter may partake of the movements of the former, a work supporting table on the bed adapted to be translated relative thereto, and means operable by the table for imparting intermittent rotation to the transverse shaft directly or indirectly through ,the intermittent actuation of the stub shaft.

5. A grinding machine of the nature disclosed including a transversely extending bed portion providing guides translatably supporting a table, a table mounted for translation upon said guides, a rearwardly extending bed portion, a grinding wheel carriage and driving mechanism supported by said rearwardly extending portion, said driving mechanism including a variable speed transmission, connections extending from the variable speed transmission on the rearwardly extending portion of the bed to the front transverse portion of the bed, and power driving connections therefrom to the translatable table unit for eifecting translation thereof at variable rates, of remote control mechanism for effecting alternative variation in rate of table translation from control stations at the front and the rear of the transversely extending portion of the bed including intercoupled gear shift levers disposed respectively, forwardly, and rearwardly of the transverse extension of the bed, shifter means jointly connecting said levers with the variable speed transmission for controlling the variations thereof, and indicating means disposed at both the front and rear control stations adjacent the shifting levers for simultaneously indicating at both stations the particular speed rate selected by actuation of either lever.

6. Agrinding machine of the nature disclosed including a transversely extending bed portion providing guides translatably supporting a table, a table mounted for translation upon said guides, a rearwardly extending bed portion, a grinding wheel carriage and driving mechanism supported by said rearwardly extending portion, said driving mechanism including a variable speed transmission, connections extending from the variable speed transmission on the rearwardly extending portion of the bed to the front transverse portion of the bed, and power driving connections therefrom to the translatable table unit for effecting translation thereof at variable rates, of remote control mechanism for effecting alternative variation in rate of table translation from control stations at the front and the rear of the transversely extending portion of the bed including intercoupled gear shift levers disposed respectively, forwardly, and rearwardly of the transverse extension of the bed, shifter means jointly connecting said levers with the variable speed transmission for controlling the variations thereof, indicating means disposed at both the front and rear control stations adjacent the shifting levers for simultaneously indicating at both stations the particular speed rate selected by actuation of either lever, and independent friction locking devices associated with the respective levers for jointly securing the parts in desired adjusted position, whereby a portion of the friction locking action may be released at either station to facilitate movement of the levers and associate parts to adjust the variable speed unit for a desired rate of translation of the table.

ROBERT E. W. HARRISON.

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