US1486342A

US1486342A - Method of making gauges and other articles

Info

Publication number: US1486342A
Application number: US309450A
Authority: US
Inventors: William E Hoke
Original assignee: Pratt and Whitney Co Inc
Current assignee: Pratt and Whitney Co Inc
Priority date: 1919-07-08
Filing date: 1919-07-08
Publication date: 1924-03-11
Anticipated expiration: 1941-03-11

Description

W. E. HOKE METHOD OF MAKING vGAUGrES AND OIHER ARTICLES Filed July 8, 1919 ml; EP- f1 mf J-lj d .1 [lmlalf 3 atented ar.. il, I9.

NITED STATES PATENT oFFlcr..

WILLIAM E. HOKE, 0F ST. LOUIS, MISSOURI, ASSIGNOB. T0 PRATTA& WHITNEY COI- PANY, 0F NEW YORK, N. Y., A. CORPORATION 0F NEW JERSEY.

METHOD or if 3:. ING GAUGE AND OTHER ARTICLES.

To all 'whom t may concern:

Be it known that I, WILLIAM E. HOKE, a citizen of the United States, residing at St. Louis, Missouri, have invented certain new and useful Improvements in Methods of Making Gauges and OtherArticles, lof which the following is a specification.

This invention' relates to a method of lapping gauge blocks or similar articles to produce identical sizes and particularly to produce v'plane parallel op osite surfaces. separated" from-each other y an assigned dimension with a high degree of accuracy. The method is in some respects similar to the method set forth in my copending applications for method of making identical articles, Serial No. 252,073, filed Aug. 30th, 1918, and for method of and machine for making gauges and other articles, Serial No. 289,591, filed April 12th, 1919.

In accordance with the present invention, I effect the lapping of the opposite end surfaces of the blocks successively instead of simultaneously as was set forth in my aforesaid a plication. Ordinarily Vthe simultaneous apping is preferable, as it is more rapid and isusually productive of more accurate results. However, for certain classes of work, particularly when the highest degree of accuracy is not required, it may be desirable to lap the surfaces successively.

In the accompanying drawing I have illustrated in' diagrammatic form a machine for practicing the method. I have also presented further diagrams by which the method will be explained. It will be understood that the drawing is for illustrative purposes only and is not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

.Of the drawing:

Fig. 1 is a vertical sectional view of a machine adapted for earryingvout my improved method.

Fig. 2 lis a plan view of the principal parts of the machine shown in Fig. 1.

Figs. 3 to 5 are diagrammatic views further illustrating the method.

The blocks to be lapped are first formed with the desired shape and with a little more than the desired length, by any usual or preferred means. When they are to be used as gauges the blocks are hardened and otherwise suitably treated, but these preliminary steps constitute no part of the present invention. After the blocks have been thus formed and treated, they are then subjected to a lapping operation or a series of lapping operations and are otherwise acted upon, in the manner tovbe described.

Referring to Figs. 1 and 2 of the drawing, it'will be seen that I provide a surface plate 1 which is suitably mounted on a table or other support; 2. The surface plate 1 is provided with a surface 3 which is made as nearly plane as possible `by any known( method. The several blocks B-B to be lapped are placed-upon the surface plate and are secured in position by cementing or otherwise. I do'not limit myself as concerns the arrangement of the blocks, but preferably they are arranged in a circular series as illustrated. For reducing the u per surfaces of the blocks B-B I provi e a lap 4 having a bottom surface 5 which is made as nearly plane as possible. This lower surface of the lap 1s suitably prepared and is charged with an abrasive such as line emery. The character of the lap and of the abrasive may be varied as required.`

The lap 4 rests directly on the blocks B and is entirely free to adjust itself as to parallelism with the surface plate in accordance with the lengths of the blocks. In order to effect lapping, the Vlap isv moved with respect to the blocks, this movement preferably being in a circular path. As illustrated, a plate 6 is secured to the la 4, this plate having a central aperture l; in which is fitted a crank 8 on a rotating spindle 9. It will be seen that the` entire lap is caused to partake of the rotative movement of the spindle. The lap is free to turn about the axis of the crank 8 and as the result of the resistance offered by the blocks, the lap is given a rotative movement in addition tov its bodily circular movement. The-movement of the lap 4 is continued until the lap engages all Aof the blocks equally. When this point is reached it may be assumed that the top surfaces of all the blocks are fiat or approximately so, although the blocks may vary slightly in length.

After the blocks have been rovided with plane surfaces at one end as escribed, they are then removed from the surface plate 1 and turned over end for end so that the flat surfaces of the blocks directly engage the flat surface of the surface plate. The

blocks are now held against movementl with titi respect to the surface plate and this holding may be effected by wringing them into place, this wringing action being a well known phenomenon whereby two flat surfaces strongly adhere. lVlien two fiat surfaces are properly wrung together actual physical contact is very closely approximated, the

actual separation frequently being as small4 as a millionth of an inch. Then the lapping operation is re cated as before described and continued, pre erably until the lap again engages all ofthe blocksequally.

Then the lapping movement is stopped and the lap is removed, thus leaving the blocks exposed. Certain blocks are then transferred in such a way `as to distribute any errors or variations in the respective lengths. It may be assumed that, with a group of blocks of slightly varying lengths, those at one part of the'group will average longer than those at another part. Following this assumption it .will be seen that the transferring must be such that the longer and shorter blocks will be commingled. In order that the longer and shorter blocks may be uniformly distributed, the transferring is preferably effected symmetrically. If the blocks are arranged in a circular series, it is to be expected that the lengths of those at one sidel will have a greater average than the lengths of those at the other side. Inasmuch as the surface plate 1 and the lap 4 are both flat, the result is that some one or two of the blocks at one side will have a maximum length and some one or two blocks diametrically opposite will have a. minimum length. The blocks between will have lengths successively varying from the maximum to the minimum. The blocks at one side of the diametral line will have lengths greater than the average and those on the other side will have lengths less than the average. The transferring of the blocks to distribute the errors and equalize the lengths is preferably done by moving alternate blocks or alternate groups of blocks to positions diametrically opposite. This places the longer blocks between the shorter ones.

For practicing the method in the preferred manner, the number of blocks in any one circular series, such as a. to p, as shown in Fig. 3, should be a multiple of four and should be at least eight. By way of example ll have shown sixteen blocks, but it will be understood that any desired multiple of four may be used. If it be assumed for in-4 stance that the blocks at one side of a diametral line have lengths greater than the average and that the blocks at the other side of the line have lengths less than the average, then it will be seen that after the diametral transposition of alternate blocks the longer and shorter blocks will, in the main, bs alternately arranged as shown in Fig. 4.' The operator has no means of determining the-position' of the diametral dividin line -w' and no means of determining w ich is the side of maximum length and which the side of minimum length, but it is not necessary for him to do so. It'will be observed .that inasmuch as the alternate blocks throughout the entire series are transposed, the `required alternate arrangement of longer and shorter blocks is secured ir- 'espective of the position of the dividing The blocks having been transferred as described, the top lap is restored to position and the lapping operation is repeated. Ob-

viously the laps will at first engage only the longer blocks, thus reducing their lengths. The lapping operation is continued preferably until the laps again'engage all of. the blocks. Obviously the blocks are more nearly uniform in length than before but there may still be some variation. Therefore alternate blocks are again transferred, as before described, and the blocks are again lapped. These operations are repeated alternately in succession for a vnumber of times,

and the final result is that all of the blocks have the same length and have their end surfaces flat and parallel.

The manner of moving or transferring the blocks may be varied, particularly in the ways set forth in my aforesaid application. It may be also desirable to change the blocks by turning some of them through 180 as indicated 1n- Fig. 5.

The blocks having been made with identical lengths and with plane parallel end surfaces, the lapping operation is then continued to reduce the lengths to the desired predetermined amount. If considerable additional lapping is required to secure the desired uniform length. it may be preferable to continue the transferring of the blocks* from time to time to avoid possible variations. The blocks may be measured in any desired way to ascertain when the predetermined lengths have been reached. Use may be made of the method set forth in my aforesaid application, but this method constitutes no part of my present invention and. need not be here described.

What I claim is: y

1. The method of reducing a number of similar blocks to produce parallel fiat end faces and identical lengths, which consists in placing the several blocks with one end face of each in engagement with a flat surface plate, placing a flat lap in engagement with the opposite end faces of the blocks, permitting'the lap to adjust itself as to parallelism with the surface plate in accordance with the lengths of the blocks, moving the lap with respect to the blocks to effect lapping, interchanging some of the blocks on the surface plate to symmetrically m with the opposite end faces of the distribute variations in length, and .repeating the lapping operation.

" 2. The method of reducing a number of similar blocks to produce parallel flat end faces and identical lengths, which consists in placin the several blocks with one end face of eac in wringing engagement with a Hat surface plate, placing a fiat lap in enagement with the opposite end faces of g the blocks, permitting the lap to adjust itself as to parallelism with the surface plate in accordance with the lengths of the blocks, moving the lap with respect to the blocks to effect lapping, interchanging some of the T5 blocks on the surface plate to symmetrically distribute variations 1n length, and repeating the lapping operation.

3. The method of reducing a number of similar blocks to produce parallel lat end faces and identical lengths, which. consists in placing the several blocks in a circular series with one end face of each in engagementl with a flat surface plate, placing a Hatv lap in engagement with the opposite 25 end faces'of the blocks, permitting the lap Vto adjust itself .as to parallelism with the surface plate in accordance with the lengths of the blocks, moving the lap with respect to the blocks to effect lapping, interchang-y 3" ing some of the blocks on the surface plate with those diametrically opposite to sym- 'm'etrically distributeV variations in. length, and repeating the lapping operation.

4. The method of' reducing a numberI of similar blocks to produce parallel dat end faces and identical lengths, which consists in placing the several locks with one 'end face of each in engagement with a iiat sur'- moving the lap with respect to the blocks in a circular path and simultaneously rotatin it to effect lapping, interchan g some o the blocks on the surface p ate to symmetrically distribute variations `in length,

rn and repeating the lapping operation.

5. The method of reducing a number of similar blocks to produce parallel fiat end faces and identical lengths, which consists in placing the several blocks with one 'end face of each in engagement with a flat surface plate, placing a flat lap in engagement with the opposite end faces of the blocks, permitting the lap to adjust itself as to parallelism with the surface plate in accordance with the lengths of the blocks, moving the lap with respect to the blocks to eiect lapping, reversing the blocks end for end and again placing them in engagement with the surface plate, again placing the lap in engagement with the blocks, permitting'the lap to adjust itself as to -parallelism with the surface plate in accordance with the lengths of the blocks, moving the lap with respect to the blocks to effect lapping, interchanging some of the blocks on the surface plate to symmetrically distribute variations in length, and repeating the lapping operation.

6. The method of reducing a number of similar blocks toproduce parallel fiat end faces and identical lengths, which consists in placing the several blocks with one end v'face of each in engagement with a Hat surface plate, placing a iiat lap in engagement with the opposite end faces of the blocks, moving the lap with respect to the blocks to eiect lapping, interchanging some of the blocks on the surface plate to symmetrically distribute variations in length, and repeating fthe lapping operation.

7. The method of reducing a number of similar blocks to produce parallel atend faces and identical lengths, which consists in placing the several blocks with one en d face of each in engagement with a Hat surface plate, placing a fiat lap in engagement with the opposite end faces of the blocks,

moving the lap with respect to the blocks to effect lapping, reversing the blocks end for end' and again fplacing them in engagement with'the sur ace the lap in engagement with the ocks, 4movin the lap with respect to the blocks to e ect lapping, interchanging some of the blocks on the surface plate to symmetrically `distribute variations in length, and repeating the lapping o eration.

In testimony w ereof, I hereto aix my si ature.

gn Enom.'

plate, again placingl