US2416703A

US2416703A - Crystal indexing fixture

Info

Publication number: US2416703A
Application number: US601051A
Authority: US
Inventors: Wilbert P Marshall
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-06-22
Filing date: 1945-06-22
Publication date: 1947-03-04
Anticipated expiration: 1964-03-04

Description

March 1947- w. P. MARSHALL I CRYSTAL INDEXING FIXTURE Filed June 22, 1945 3 Sheets-Sheet l -WILBERT RMARSHALL M f 4, 1947' w P. MARSHALL 2,416,703

: CRYSTAL INDEXING FIXTURE I Filed June 22, 1945 3 S ee she t 2 I v- 71.1111 ll 7 '4 l3 7 WILBERT P. MARSH ALL WWW March 4, 1947 w. MARSHALL 2,416,703

\CBYSTAL INDEXING FIXTURE Filed June 22, 1945 I I 3 Sheets-Sheet 3 W|LBERT P. MARSHALL I Patented Mar. 4, 1947 UNITED STATES PATENT OFFICE I I I 2,416,703 Y I I CRYSTAL INDEXING FIXTURE Wilbert P. Marshall, Cleveland Heights, Ohio Application June 22, 1945, SerialNo. 501,051

4 Claims. (01. 51:21?)

(Granted under the act of March 3, 1883, as

amended April 30, 1928.; 370 0. G. 757) The present invention has to do with the production of piezoelectric crystal elements and more particularly the cutting of piezoelectric elements from a crystal or portion of a crystalof piezoelectric material with reference to certain axes of the crystal.

An important requirement to the attainment of accuracy, economy and rapid production in such cutting is the provision of means for firmly holding the piece of crystal material in various predetermined positions relative to the cutting tool, in a manner to afford operation of the tool on a large portion of the material in a single operation, and to afford rapid and accurate re-adjustment of the relative position of tool and workpiece for other operations of the tool on the work-piece without disturbing other angular relations intended to remain constant.

It is therefore an object of the'invention to provide a holding fixture in which the crystal may be adjustably held in any position within a substantial range of adjustment sufficient to bring crystals of diiferent sizes and slight variation in shape, into a position to align a given axis of the crystal with the cutting plane of the tool,

the fixture being capable of permitting readjustment of theposition of the crystal with reference to the tool to change the angular relation of another axis or'axes to the tool while maintaining the first alignment.

Another object is to provide in such a fixture, an indexing means whereby once the fixture is adjusted to hold the crystal with one axis in alignment with the tool, the crystal may be adjusted about this axis in predetermined angular steps.-

Another object is the provision of means whereby the crystal may be adjusted about the first mentioned axis independently of the indexing means.

A further object is to provide a crystal holder which together with the quality of adjustability shall be capable of affording free access to a large portion of the crystal by the tool.

Various other objects and advantages of the invention will become apparent upon perusal of* Fig. l is a perspective view, approximately one at Fig. 2, and partly in section.

Fig. 4 is a cross-sectional view of one of the 1 clamping shoes taken through the axis of one of the clamping screws in a plane normal to the cross-sectioned portion of Fig. 3.

Fig. 5 is a side elevation on a much reduced scale and in diagrammatic form, showing the crystal holder and a cutting tool in operative relation.

Referring to the drawings more in detail, the device is comprisedof a carriage element I0 adapted to be removably mounted-on the bedplate ll of a cutting tool such as a cutting disk I2, in fixed angular relation to the tool in all three} dimensions, the angular relation being fixed in any known or other suitable manner as by a feather-key or spline [3 in slidable engagement with a longitudinal T-slot 14 formed in the bed, while fixation is obtained through clamping bolts I 5 and I6. A support member I! pivotally mounted on the carriage l0 through means of 'a pintle [8, supports a ring-form crystal holder I9 rotatably mounted in the support, about an axi parallel to the axis of the pintle l8, both fixed relative to the carriage I8 and consequently fixed relative to the tool bed I I. i

A pair of leveling screws 20 threaded in the end of the support opposite the pivoted end and bearing upon the upper surface of the carriage ll],

together with a locking bolt 2|, afford a small angular adjustment of the support about the axis of the pintle and consequently an angular adjustment of the holder IS in its plane of rotation for adjustment of the holder, and a crystal held therein, to a given starting or zero, angular position with reference to the carriage l0 and tool l2. Clamping shoes 22 carried by the holder'l9, and adjustable radially of the holder through clamping bolts 23 in threaded engagement with the holder, serve to adjustably hold and clamp'a crystal to be operated upon, such as the crystal 24 (Fig. 1'), at various angles to the aXis of the ring-form holder within a substantial range of adjustment sufiicient to ,bring'the longitudinal axis of crystals of different sizes and slight variation in shape, into alignment with the axis of the ring-form holder,

= To compensate for irregularities in the lateral surfaces of a crystal, the clampingv shoes 22 are v aiforded a slight universal movement each through provision of a slightly loose fit to the ends of its clamping screws 23, and the provision of a l cork pad 25, the latter, due to its resiliency, tending to conform to vary slight surface irregularlties.

Loose connection of the shoe '22 with the clamping screw 23 is obtained through the use of a pair of yoke elements 26 secured by screws 21 and embracing the neck portion of the headed end of the clamping screw. 7

The ring-form holder I9 has bearing in the support I! by virtue of its loose lit in thetwo inwardly facing, annular, rabbeted portions 28 formed about the openings 29 in the front and rearplates '30 and 3| which plates with the spacer member 32 constitute the body of the sup- 'port H. The plates and spacer member may;

be secured together in any known or other suitable manner as by clamping screws asshown at 33 in Figs. 1 and 2.

A centering pin 34 passmgthrough registering openings 35 and 36 in the support l1 and One of a series of openings 31 in the ring-form holder l9 provides means for locking the holder against rotationin the support.) This enables V consequently the crystal to be indexed angularly in either direction from the starting or zero position by withdrawing the centering pin, ro-

tating'the holder to bring the next or other desired one of the openings 31 into register with the openings in the support, and locking the parts inadjusted position by reinsertion of the alignment tolock the holder in the new predetermined angular position. I

In operation the crystal 24 is first accurately adjusted and clamped in the'holder by means of the adjustable clamping shoes and the angular adjustment afiorded by the leveling-screws 20,

to-bring certain axes of the crystalinto a predetermined orientation relative to the carriage member I0. In the present instance the crystal :24 is one in the form of an elongated rectangul'ar prism with rectangular pyramidal ends, to be cut or sliced along planes parallel to the longitudinal axis of the crystal and at 45 degrees to the side faces. After the crystal has been clamped .in the holder with its three axes orientated in parallelism with the threelrectangularaxes (longitudinal, vertica1 and transverse horizontal); of the carriage 10, as indi- 4 tion-determining means on the carriage member I0, enables the crystal to be originally adjusted in the holder in the desired orientation with respect to the carriage while situated at some place more convenient than the tool bed, as on a special adjusting bed or bench not shown, providing ready access to the crystal for the application of suitablemeasuring'and indicating devices for deter-' mining'correct adjustment, the spline assuring an orientation of the carriage with respect to the tool bed the same as it had with the bed or bench on which the alignment of the crystal was established.

I Obviously the original alignment of the crystal may be made with the carriage mounted on the tool bed. Determination of proper alignment may be "made in any known or other suitable manner as by determination of the angular relation of the crystal faces to the carriage.

While only one practical embodiment of the invention has been herein shown and described cated in Fig, l,'the carriage being clampedon:

the bed of the cutting tool,--the

34,15 withdrawn and the crystal indexed 45 degrees about 'the axis of the holder as indicated in. Fig. 5 and locked in this position by're'insertionfof the pin. Now, movement of the cutting tool I2 toward the crystal will result in. a slicing cut into with the longitudinal axis of the original prism but having its sides canted at 45 degreesv to those of the mother crystal.

Provision .ofthe spline l3 or equivalent posifor the sake of disclosure, it is to be understood that the invention is not limited to the specific embodiment disclosed, but contemplates all such modifications and variations thereof as fall fairly within the scope of the appended claims.

. The invention described herein may be manufactured and used by or 'for the Government of the United States of America for governmental purposes-without the payment of any royalties thereon or therefor. r

What is claimed is:

1. A crystal indexing fixture comprising a carriage, a support pivotally mounted on the carriage to swing about an axis fixed relative to the car.- .riage said support comprising a pair of upright frontand rear plates spaced apart parallel and having circular, openings with rabbeted rims facing each other, a ring form crystal holder mounted between said plates with its opposite ends fitted into said rabbeted rims for rotation therein, a plurality of pairs ofclamping screws extending radially through the holder between the plates, each pair terminating within the holder at a work-clampingv shoe supported at spacedpoints on the ends of the screws for slight universal movement relative thereto, whereby a crystal may be clamped in the ring-form holder and adjusted .angularly with respect to the axis of the ringform holder. I i f 2.- YA crystal indexing, fixture comprising a car- ...ri'age, a support pivotally mounted on the care riage to swing about an axis-fixed relative to the carriage, said support comprising a pair of upright. front and rear plates spaced apart paralleland having circular openings with rabbeted rims facing each other, a ring form crystal holder mounted between said plates with its opposite ends fitted into said rahbeted rims for rotation therein, a plurality .of pairs of clamping screws -means ior locking the ring-form holder in variouspredetermined angular adjustments relative to the support. Y

3. A crystal indexing fixture comprising acarriage; a support pi-votally mounted on the carriage to swing about an axis fixed relative to the carriage, saidsupport comprising a. pair of upright front and rear plates spaced apart par-3 allel and having circular, openings with rabbeted rims facing each other, a ring form crystal holder mounted between said plates with its opposite ends fitted into said rabbeted rims for rotation therein, a plurality of pairs of clamping screws extending radially through the holder between the plates, each pair terminating within the holder at a work-clamping shoe supported at spaced points on the ends of the screws for slight universal movement relative thereto, whereby a crystal may be clamped in the ring-form holder and adjusted angularly with respect to the axis of the ring-form holder, together with a centering pin passing through registering openings in the plates and one of a circular series of openings in the ring form holder.

4. A crystal indexing fixture comprising a carriage, a support pivotally mounted on the carriage to swing about an axis fixed relative to the carriage, said support comprising a pair of upright front and rear plates spaced apart parallel and having circular openings with rabbeted rims facing each other, a ring form crystal holder mounted between said plates with its opposite ends fitted into said rabbetedrims for rotation therein, a plurality of pairs of clamping screws extend- .form holder, the clamping screws in each pair being spaced axially of the ring-form holder.

W1LBERT P; MARSHALI L REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,372,025 Smith Mar. 20, 1945 2,214,166 Hertlein Sept. 10, 1940 2,107,566 Gardner Feb. 8,1938 1,047,424 Lumsden Dec. 17, 1912 1,121,995 Elvers Dec. 22, 1914