US1314154A

US1314154A - Grlnding-machine

Info

Publication number: US1314154A
Authority: US
Publication date: 1919-08-26
Anticipated expiration: 1936-08-26

Description

A. SCRIVENOR.

GRINDING MACHINE.

APPLHLAHON FILED NOV. I3. 1911.

Patented Aug. 26, 1919.

3 SHEET SHEET 1.

FLq I A. SCRIVENOR.

GRINDING MACHINE.

APPLICATION HLED NOV-13.1917. 1,314,154. Patented Aug. 26, 1919.

3 SHEETS-SHEET 2- FL qlll.

gnucuhm A. SCRIVENOR GRINDING MACHINE.

APPLICATION FILED NOV. 13. 1911.

Patented Aug. 26, 1919.

3 SHEETS SHEET 3- ARTHUR SCRIVENOR, 0F RICHMOND, VIRGINIA.

GRIN DIN G-MACHIN E.

Specification of Letters Patent.

, Patented Aug. 26, 1919.

Application filed November 13, 1917. Serial No. 202,621.

To all whom it may concern Be it known that I, ARTHUR SCRIVENOR, a citizen of the United States, residing at Richmond, in the county of Henrico and State of Vir inia, have invented certain new and useful Improvements in Grinding-Machines, of which the following'is a spamfication.

My invention relates to machines for grinding cutting tools of cylindrical shape, and is described as used for grinding the threads or teeth of steel burs used in dressing grind-stones; but it is not limited to such use.

The threads of steel burs may be straight or parallel with the axis of the bur, diagonal to the axis of the bur, or spirally arranged on the face of the bur. Combinations of these forms of thread are usedto form diamond-point, chisel-point, and other 1nterrupted forms of thread. In another application, filed on May 9, 1917, Serial No. 167,578, I have described a machine for grinding the spiral threads of burs. In the present application a machine or attachment for grinding straight threads or dlagonal threads, and also straight and diagonal 1nterruptions on spiral threads is descrlbed; and the object of this invention is to provlde a machine whereby the said grinding may be accomplished with accuracy, and rapidly.

Though these two machines are described and claimed in separate applications, 1n practice it is convenient to incorporate them in one machine, as illustrated in the drawings of the application filed May 9, 1917, on the machine for grinding spiral threads referred to above.

In the drawings accompanying and forming a part of this specification, and in which like numerals refer to like parts in the sev eral views,Figure I shows the machine in side elevation; Fig. II in end elevatlon, and Fig. III in plan. Fig. IV illustrates the abrasive wheel stand, and Fig. V illustrates the table on which the abrasive wheel is adjusted for cutting straight or diagonal burs. Fig. VI is a vertical longitudinal section of the machine, and *ig. VII is an end View of the same with the casing in section to show the mechanism within. Fig. VIII is a detail of the indexing wheel shown in Fig. VI.

()n a table 100 is carried the grinding wheel 110, mounted on a shaft which may be driven by pulleys and belts from overhead lincs, or by means of an electric motor,

'The motor 111 as shown at 111 in Figs. I, II, and III. is preferably mounted on a bracket 112 which is pivoted on the table 100 at a point exactly beneath the center of the abrasive wheel 110. In Fig. III the bracket 112 is shown pivoted at 113. See also Fig. V. The motor bracket 112 is secured to the table 100 by means of bolts passed through the slots in the foot of the bracket and through one or other of the holes 117, 118 and 119 in the top of the table.

Referring to I, II, III and VI, straight and diagonal cut teeth are ground on work supported on the spindle 150. The spindle 150 is carried in bearings mounted in the housing 151, which bearings permit rotation of the spindle, a thrust bearing being added to prevent GDClWlSBDlOtiOD of the spindle relative to the housing.

Near the farther end of the spindle 150 is mounted a cylindrical cam 152, 1n which are cut a straight roller path and diagonal paths having the same lead as the diagonal bur threads to be ground. At the extreme end of the spindle 150 is shown an indexing wheel 153 for use in setting the several threads of a bur successively in position for grinding. For fine setting I use the worm and gear adjustment shown in Figs. VI and VII in which 15-1 is a worm wheel rigidly secured to the

spindle

150, and 155 is a worm cut on a shaft 156v having a milled head 157, and mounted in

bearings

158, 159, which bearings are secured to the frame of the cam 152. In a bracket 160 to one side of the cam 152 is adjustably mounted a pin 161, carrying a roller 162, the said roller )eing mounted on the pin 161 by means of a small annular ball bearing to prevent wear of the pin or of the bore in the roller. If the roller be of small size, so that a larger number of slots may be used on one cam, the outer race of the ball bearing may be used as the cam roller. Such use also simplifies construction, and reduces the number of parts. The roller 162 and pin 161 are held in position by means of a set screw 163. The roller 162 may be withdrawn from the slot in the cam by merely slacking the set screw, and

prevented from rotating by the cam roller 162, and the worm wheel is pinned or keyed to the spindle; consequently the turning of the worm 155 revolves the spindle 150, and

the work carried by it. This arrangement handle 170. When the handle is operated to oscillate the shaft 169, the sector'168 engaging the rack 167 imparts to the slide 164:,

and consequently to the work carried by the spindle 150, a reciprocating motion in a horizontal plane. The movement of the slide 164:. is limited by

stops

171 and 172, secured to the walls of the bracket 166, which stops limit the motion of the sector 168. I

The bracket 160, carrying the pin 161 and cam roller 162, is attached to the bracket 166. If the roller 162 is in the straight slot of the cam when the handle 170 is actuated, the spindle and work will have only a reciprocating motion. But if the roller 162 is engaging in one of the diagonal slots on the cam 152, when the handle 170 is actuated the work will be given a reciprocating combined with a rotary motion; and any point on the work will follow a path similar to the path of the slot on the cam 152 in which the roller 162 is engaging. So, to provide for thegrinding of a thread of any practicable inclination to the axis it is only necessary to provide a slot of like inclination on the cam 152. The practical limit to such inclination is that at which the friction between the roller and the cam path becomes too great for smooth and free movement of the cam.

The front of the bracket 166 is slidably mounted in slots in a block 173. The block is also slida bly mounted on ways carried by the table 100, and is adjustable in a vertical direction by means of the screw gear 174: operated by the hand wheel 175, and working in a fixed nut 176 carried by the bracket 177 bolted to the table 100. When the height of the block 173 is so adjusted, so also is the height of the bracket 166, and consequently of the work spindle 150, so that the work may be properly presented to the abrasive wheel. This wheel is shown in Fig. HT, ar-

ranged to grind a thread inclined at an angle of 45 degrees to the axis of the work.

Assuming that the abrasive wheel is in position and that the work is at the proper height and the thread to be ground correctly set, a forward movement of the handle 17 0 will cause the thread to be brought into enparts,for instance, the roller 162 and cam slot, the teeth of the rack 167 and sector 168,-would have the effect of changing the setting of an inclined work thread, and a spoiled thread would be likely to result. I

therefore provide means for quickly bringing the work thread out of contact with the abrasive wheel before the return stroke, and

whereby may be again quickly brought into position for engagement before the next forward stroke, and without disturbing the vertical adjustment of the block 17 3, as follows:

Journaled in bearings 180 in the block 17 3 (see Fig. VI) is a shaft 181 provided at one end with a handle 182. Pinned to the shaft 181 is the lower end of a toggle 183, jointed at 184, and the upper end 185 of which is mounted on a short shaft or pin 186 journaled in bearings 187 attached to the sides of the bracket 166.. Stops for the motion of the toggle are attached to the bracket 166 at 188 and 189. The toggle shaft 181 is not in contact with the bracket 166; but passes through elongated openings 190 in the sides of the bracket. In Fig. VI the toggle is shown in its extended position, and bearing against the stop 188. Compared with the position of the block 173, the bracket 166 is now in its highest position. Remembering that the height of the shaft 181 is fixed (relatively to the height of the block 17 3), if the handle 182 be now, operated to throw the toggle joint 184 against the stop 189, the distance between the centers of the shafts 181 and 186 will be reduced, and by the amount of this reduction will the shaft 186 and the bracket 166 be lowered. This amount may be arranged to suit the work in hand by making the stop 189 of the proper length. I have found that a drop of from to is'suflicient. The control of the work spindle is now as follows :-The block 173 carrying the bracket 166 having been adjusted to the proper height, and the handle 170 pulled back to bring the sector 168 against the stop 171, the handle 182 is then pulled back, extending the toggle183. Holding back the handle 182, the handle 170 is carried forward, bringing the work thread 7 then carried forward, throwing the toggle joint 184 against the stop 189, lowering bracket 166, and lowering the work from engagement with the abrasive wheel. The handle 170 is thenpulled back to its rearward position; and the work is set for the grinding of the next thread. Pulling back the handle 182 to again raise the work, the grinding operation is repeated.

Referring again to Fig. VI, the indexing wheel 153 is removably mounted on the extended hub of the worm gear 154, and clamped thereon by the nut 192. A number of indexing wheels may be employed where the range of work to be ground is large. Preferably these indexing wheels are notched on the periphery, and engaging in the notches is a spring finger 191, (see Fig. VIII), attached to the slide 164. By means of the worm gearing 154, 155, the notches of the indexing wheel are accurately set against the'finger 191, so indexing the work, and without disturbing the cam 152 through the axis of which the spindle 150 is free to revolve. So long as the roller 162 engages a path of the cam. 152 the worm gearing 151, 155, forms an effective lock for the spindle 150, holding it in position subject to the control of the movement of the slide 161 and the slots of the cam 152.

I have described my machine as arranged for grinding bur and similar threads; but it can with advantage be used for grinding other articles in which precision is required.

In the claims I have referred to the rectilinear motion of the work spindle as the advance, for the sake of brevity, and it is to be understood that by advance I refer to motion in line with the axis in either direction, toward or from the grinding wheel.

I claim 1. The combination of a spindle rotatably mounted in bearings, means for securing the work to the spindle, a cylindrical cam rotatably mounted on and concentric with the spindle, a fixed roller adapted to engage a path on the cam, a worm mounted on the cam body, and a worm wheel mounted axially and rigidly on the spindle and engaging the worm.

2. The combination of a spindle mounted in bearings, a cylindrical cam axially mounted on the spindle, a fixed roller engaging a path of the cam, a worm mounted on the cam loody, and a worm wheel axially and rigidly mounted on the spindle, and engaging the worm.

3. The combination of a spindle mounted in bearings, means for securing work to the spindle, an indexing wheel fixed on the spindle, a stop adapted to engage in a notch on the index wheel, a worm wheel fixed on the spindle, a fixed worm engaging in the worm wheel, and adapted when revolved to revolve the worm wheel and with it the spindle to index the work.

4. The combination of a spindle mounted in bearings, means for securing work to the spindle, a platen carrying the s indle bearings, means for imparting to tie platen a forward movement and a backward movement, means for adjusting the vertical position of the platen, a second adjusting means whereby the platen may be lowered and raised again to its original position without disturbing the adjustment of the first adjusting means.

5. The combination of a table, an abrasive Wheelmounted on the table, a block vertically adjustable with reference to the table, means for adjusting the block, a bracket vertically adjustable on the block, means for adjusting the bracket, a platen mounted on the bracket and adapted to reciprocate on the bracket, means for reciprocating the platen, a work holder mounted on the platen, and means for securing the work to the work holder.

6. The combination of a table, dressing means mounted on the table, a work holder, means for bringing the work into engagement with, and for withdrawing it from, the dressing means, means for adjusting the vertical height of the work with reference to the dressing means, and a second adjustingmeans for changing the vertical height of the work to bring it into and out of engagcment with the dressing means.

7. The combination of means for dressing the work, means for supporting the work, a toggle mounted at one end on a fixed hearing and having its other end pivoted to the work supporting means and so arranged that when operated the work is brought into ongagement with or out of engagement with the dressing means, and means for operating the toggle.

8. The combination of means for dressing the work, means for supporting the work, means for reciprocating the work in a horizontal plane into and out of engagement with the dressing means, means for controlling the position of the work in a horizontal plane with reference to the dressing means, and means for adjusting the position of the work in a vertical plane and adapted to bring it into and out of engagement with the dressing means.

In testimony whereof I affix my signature, in presence of two witnesses.

ARTHUR SCRIVENOR. Witnesses:

M. E. MALONE, A. L. CAMPBELL.