US3672099A

US3672099A - Automatic rock thinsectioning machine

Info

Publication number: US3672099A
Application number: US69381A
Authority: US
Inventors: George R Parkhurst
Original assignee: University of California
Current assignee: University of California
Priority date: 1970-09-03
Filing date: 1970-09-03
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A machine for thinsectioning rock specimens includes a turntable intermittently rotatable on a frame to carry specimens in holders to a saw station at which a rotary saw on an arbor is motor driven and is mounted for adjustment of its rotational axis in various directions and then to a grinder station in which a motor driven grinder is likewise mounted for rotation about an axis movable into various different positions and to be approached more or less closely to the rock specimen on the turntable.

Description

United States Patent Parkhurst [4 1 June 27, 1972 AUTOMATIC ROCK THINSECTIONING MACHINE lnventor: George R. Parkhurst, Dixon, Calif.

Assignee: The Regents of the University of California, Berkeley, Calif.

Filed: Sept. 3, 1970 Appl. No.: 69,381

US. Cl. .L ..5l/3, 125/13 R, 51/134 Int. Cl..... ..B24b 7/04 Field olSearch ..l25/l3;5l/3, 134

References Cited UNITED STATES PATENTS Gardner ..51/l34 X 2,382,257 8/1945 Ramsay ..l25/l3 X 3,289,663 12/1966 Cary ..,.l25/l3 3,225,493 12/1965 Kulbicki ..5 H134 Primary Examiner-Harold D. Whitehead Attorney-Lothrop & West [5 7] ABSTRACT A machine for thinsectioning rock specimens includes a turntable intermittently rotatable on a frame to carry specimens in holders to a saw station at which a rotary saw on an arbor is motor driven and is mounted for adjustment of its rotational axis in various directions and then to a grinder station in which a motor driven grinder is likewise mounted for rotation about an axis movable into various different positions and to be approached more or less closely to the rock specimen on the turntable.

2 Claims, 8 Drawing Figures PATENTEDJum I972 3. 672,099

sum 20F 3 INVENTOR. GEORGE R. PARKHURST ATTO RN EYS PATENTEDJum r972 SHEETBUF 3 QQQ? INVENTOR. GEORGE R. PARKHURST ATTORNEYS AUTOMATIC ROCK TI-IINSECTIONING MACHINE In various phases of the study of rocks, it is important to have a section of a rock specimen or sample which conforms very accurately to a geometrical and dimensional standard; that is, a rock section should be a very thin slice of rock with the opposite sides of the slice very nearly planar, parallel or at a known angle to each other and a known distance apart. This is particularly advantageous when the specimen is to be examined microscopically and with various kinds of light.

It is therefore an object of the invention to provide an automatic rock thinsectioning machine which is effective to process a rock sample from its original form to a uniform configuration for examination.

Another object of the invention is to provide a automatic rock thinsectioning machine which can make a large number of rock sections without requiring particular supervision by an operator.

Another object of the invention is to provide a rock thinsectioning machine which is effective to treat uniformly specimens of various different kinds of rock.

A further object of the invention is to provide an automatic rock thinsectioning machine which can be adjusted and set in various difierent ways in order to provide the kind of specimens desired.

A further object of the invention is to providean automatic rock thinsectioning machine which maintains its accuracy over a protracted period of time.

An additional object of the invention is to provide an automatic rock thinsectioning machine which is an improvement over other devices heretofore utilized for a similar purpose.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIG. 1 is a plan of an automatic rock thinsectioning machine pursuant to the invention; 7

FIG. 2 is a side elevation of the structure shown in FIG. 1, certain portions being broken away to reduce the size of the figure;

FIG. 3 is an enlarged detail of a portion of the turntable and specimen-holding structure;

FIG. 4 is a cross section, the plane of which is indicated by the line 4-4 of FIG. 3;

FIG. 5 is an end elevation of the structure of FIG. 1, certain portions being broken away to reveal the interior construction:

FIG. 6 is a view similar to a portion of FIG. 5 but showing the grinder mount as distinguished from the saw mount;

FIG. 7 is an end elevation of the grinder mount shown in FIGS. 6, portions being broken away;

FIG. 8 is an elevation of the other end of the grinder mount shown in FIG. 6 but with some parts omitted and other parts in distorted and spaced relationship in order to clarify the disclosure.

As successfully embodied in a form that has produced a large number of rock thinsections automatically, the device includes a frame 6 made up of the customary shapes and angles to afford a mounting for the remaining part of the structure. Disposed on the frame 6 at about waist height and for rotation about a first axis 7 is a turntable structure 8. This preferably includes not only an upper circular disk 9 but likewise a nether, intermittent motion mechanism 11 of a standard kind. The turntable mechanism is mounted on the frame 6 and is provided with a drive shaft 12 receiving rotational notion from a motor 13 mounted on the table 6. Although the motor 13 revolves continuously when energized, the intermittent motion mechanism 1 l rotates the table 9 about the axis 7 in a series of intermittent steps so that the periphery of the turntable advances quite slowly.

Adjacent one comer of the table 7 and secured thereto and arranged adjacent the periphery of the disk 9 is a grinder mounting 16. This includes not only a base 17 but a pair of

guides

18 and 19 arranged substantially parallel to the axis 7.

Designed to slide on the grinder mounting 16, is a grinder slide 21 including a cover 22 secured to a pair of channelled

slide member

23 and 24 engageable with the

guides

18 and 19 vertically movable therealong. In order to arrange for such vertical movement, the cover 22 carries a central boss 26 internally threaded to engage a screw 27 having a bearing 28 secured to the mounting 16 and provided with a hand wheel 29 at the end of the screw shaft. Upon rotation of the wheel 29, the screw shaft 27 in engagement with the member 26 moves the slide up or down with respect to the mount.

Also attached to an extension of the cover 26 is a grinder plate 31. This grinder plate, as particularly shown in FIG. 8, adjacent its bottom is provided with a pivot pin 32 extending along its own axis 33 which is in a plane perpendicular to the axis 7 and permits the grinder plate 31 to swivel or pivot about the axis 33. In order to govern and control such pivotal movement, the grinder slide 21 is provided with a pair of

upstanding cars

36 and 37, both of which threadedly carry

thumbscrews

38 and 39 disposed oppositely. Between them the screws engage a tongue 41 integral with and upstanding from the grinder plate 31. By this means and by adjusting the

screws

38 and 39 the tongue 41 can be moved within limits to any desired position between the

members

36 and 37, thus providing rotation about the axis 33 as defined by the pivot pin 32.

The grinder plate 31 is L-shaped in plan and has an extension 42 carrying a pivot pin 43, the axis 44 of which is perpendicular to the axis 33 and is likewise perpendicular to the axis 7 so that the three axes are mutually normal to each other. Mounted to rotate about the axis 44 on the pin 43 is a grinder quill plate 46 at its upper end carrying a broad tongue 47 disposed between the ends of

screws

48 and 49 projecting from ears 51 and 52 on the grinder plate 42 so that by adjustment of the

screws

48 and 49 the grinder quill plate 46 can be rocked about the axis 44 within limits.

Extending outwardly from the grinder quill plate 46 are

separable bosses

56 and 57 designed to encompass a grinder quill 58. The quill is of circular cylindrical configuration symmetrical about an axis 59 and makes a relatively loose fit in the lower boss 57. The quill is slightly enlarged and carries threads 61 near its upper end that interengage with similar threads cut on the interior of the upper boss 56 so that when the quill is rotated about the axis 59, it is likewise and by that token axially translated.

Within the quill 58 are appropriate bearings (not shown) effective to support for high-speed rotation a grinder shaft 62 at its lower end designed to be fitted with any appropriate type of grinding wheel 63. At its upper end the shaft 62 carries a pulley 64 designed to receive a high-speed belt 66 likewise trained around a similar pulley 67 at the upper end of an electric motor 68 fastened to the grinder slide cover 22. When the motor 68 is energized, the grinding wheel 63 is correspondingly driven. Mounted on the grinder quill plate 46 and extending loosely through the grinder plate 31 is worm shaft 71 mounted in suitable bearings and having at one end a graduated adjusting knob 72. At the other end, the worm shaft 71 carries a worm 73 in loose mesh with a straight toothed gear wheel 74 fast on the quill 58. When the knob 72 is revolved, the worm shaft and the worm 73 are simultaneously revolved and correspondingly rotate the gear wheel 74. This produces a corresponding rotation of the quill, which moves axially in response to the effect of the threads 61.

During such axial motion, the grinding wheel 63 is moved toward or away from the turntable and the gear wheel 74 moves axially with respect to the worm shaft 71, the amount of such axial motion being small enough so that the gear wheel 74 never comes out of mesh with the worm 73. If desired, the end of the shaft 71 carries a flexible drive shaft 70 for rotating a counter 75 appropriately mounted in a visible location so that the number of turns of the knob 72 can be indicated to afford the user an idea of the distance through which the grinding wheel 63 has been axially moved toward or away from the turntable.

In a somewhat comparable fashion on another comer of the frame and also adjacent the turntable, there is disposed a saw mounting 76 having a saw slide 77 thereon moved up and down parallel to the axis 7 by means of a hand wheel 78 constructed and connected substantially as previously described in connection with the grinder mounting. In a similar fashion the cover plate of the saw slide at one side carries a saw plate 79 mounted for rotation about a transverse axis coincident with or parallel to the similar axis of the grinder and positioned by a pair of

hand screws

81 and 82 threaded into

cars

83 and 84 on the saw slide 77 and engaging a tongue 86 projecting from the saw plate 79.

Mounted in turn on the saw plate 79 is a saw quill plate 87 designed to rock about a pivot pin 88 symmetrical with an axis 89 parallel to the comparable axis of the grinder and at right angles to the other axes of the saw mounting. The saw quill is positioned about the axis 89 by a pair of screws 91 and 92 in ears 93 and 94 on the saw quill plate and engaging a tongue 96 on the saw plate.

On the saw quill plate is disposed a saw quill 97 held in blocks 98 so that its axis 99 is approximately parallel to the axis 7, although by means of the adjustments that axis can be rocked in at least two planes to afford some variation in position of the saw quill axis. There is no vemier or fine adjustment of the saw quill in the blocks 98 as there is with the grinder quill in the

blocks

56 and 57.

The saw quill carries a saw shaft 101 coincident with the axis 99 and the shaft 101 at its lower end has a circular saw 102. At its upper end, the shaft 101 has a pulley 103 joined by a belt 104 to a pulley 106 on the shaft 107 of a motor 108 mounted on the cover 77. When the motor 108 is energized, the saw 102 is rotated at high speed.

Although various different means can be provided for holding specimens on the turntable and such means can include vacuum retention and mechanical retention, I have in the present instance so contoured the turntable as to afiord a number of identical, mechanical specimen holders. A description of one, therefore, applies to the others. As particularly shown in FIGS. 3 and 4, at each specimen station the turntable 9 is provided with a pair of trapezoidal guides III arranged so that their facing edges 1 12 and 113 are parallel to each other. Also extending between successive guides 111 is a stop 114 having an edge 116 at right angles to the

edges

112 and 113. Beneath the center of each station, the turntable is provided with a radial bore 117 within which a plunger 118 is movable. The plunger has a projection 119 adapted to slide on the planar undersurface of the turntable to preclude rotation of the plunger 118 within the bore 117. A fingerhook 121 also depends from the plunger.

The upper portion of the plunger is provided with an upstanding wall 122 having an edge 123 parallel to the edge 116 of the stop 114. A screw 126 passes through the hollow center of the plunger, is anchored in the turntable and confines a helical spring 127 between the head of the screw and an intumed flange 128 on the plunger. With this mechanism, the user by crooking his finger against the extension 121 withdraws the plunger from the bore partially, thus compressing the spring 127 and moving the wall 123 away from the stop 116. A specimen, properly shaped, is dropped into position on the turntable top and the finger extension 121 is then released so that the spring 127 urges the plunger toward an inner position, thus gripping the specimen between the extension 123 and the stop 114 with the specimen appropriately located between the side members 1 12 and 113.

In connection with the use of the mechanism, sometimes it is desirable to provide means for removing debris and for providing cooling water to the grinding and cutting mechanisms. For that reason, as shown in FIG. 5, a water tube 129 is provided to discharge into the vicinity of the grinder or of the saw or both. Furthermore, there is often provided, although only'partially shown, a partial or complete enclosure 131 or guard around the structure particularly above the turntable so that any flying debris or splashing water will not escape but will be confined closely to the vicinity of the turntable.

In the customary use of this device, a relatively rough rock specimen is first mounted on the turntable and then is advanced toward the rapidly rotating saw 102 by means of the energized motor 13 advancing the turntable 8 intermittently by short increments. As an irregular rock specimen passes by the saw, it is sliced or cut off to provide a thin section. This section, however, is relatively irregular and rough because of the nature of the cut provided by the saw blade 102.

This thin section so provided is then remounted as just described between the

stops

112 and 113 and is held by the gripping

surfaces

123 and 116 and so rotates beneath the grinder 63 as the table intermittently rotates. Since the grinder can be adjusted in various different ways and has a micrometric adjustment toward and away from the turntable, a very accurately ground and smooth or polished surface can be afforded on the specimen as it passes beneath the grinding wheel. The depth or thickness of the specimen can be carefully regulated, particularly by using the knob 72, so that a specimen thickness accurate to a fraction of a thousandth of an inch can be afforded.

Normally, the finished surface of the specimen is parallel to the plane of the turntable but if desired, a prismatic specimen can be afforded by appropriately cocking or tilting the grinding wheel. The attitude of the grinding wheel axis can be varied during operation to afford surfaces having curvature if desired. Usually, however, adjustments are made so that the grinding axis is made as nearly as possible exactly normal to the plane of the turntable so that the specimen will be an accurate parallelopipedon. Since the turntable advances intermittently a few degrees per minute, it is possible to afford approximately 15 or 20 specimens extremely accurately prepared (to the desired thickness within a fraction of a thousandth of an inch) in 3 or 4 hours.

What is claimed is:

1. An automatic rock thinsectioning machine comprising a frame, a horizontal turntable, means for mounting said turntable on said frame for rotation about a first axis, means on and disposed above said turntable for holding a rock specimen to be thinsectioned, a grinder mounting secured to said frame alongside and extending above said turntable, a grinder slide, means for moving said grinder slide on said grinder mounting in a direction parallel to said first axis and toward and away from the top of said turntable, a grinder plate, means for mounting said grinder plate on said grinder slide for rotation about a second axis located in a plane perpendicular to said first axis, a grinder quill plate, means for mounting said grinder quill plate on said grinder plate for rotation about a third axis perpendicular to said second axis and located in a plane perpendicular to said first axis, a grinder quill, means for mounting said grinder quill on said grinder quill plate, a grinder shaft, means for mounting said grinder shaft for rotation in said grinder quill above said turntable and about a fourth axis intersecting said turntable and approximately parallel to and movable with respect to said first axis, means for rotating said grinder shaft about said fourth axis, a grinder on said grinder shaft and overlying said turntable, a saw mounting secured to said frame alongside and extending above said turntable and adjacent to said grinder mounting, a saw slide, means for moving said saw slide on said saw mounting in a direction parallel to said first axis and toward and away from said top of said turntable, a saw plate, means for mounting said saw plate on said saw slide for rotation about a fifth axis parallel to said second axis, a saw quill plate, means for mounting said saw quill plate on said saw plate for rotation about a sixth axis parallel to said third axis, a saw quill, means for mounting said saw quill on said saw quill plate, a saw shaft, means for mounting said saw shaft for rotation in said saw quill above said turntable and about a seventh axis intersecting said table and approximately parallel to and movable with respect to said first axis, means for rotating said saw shaft about said seventh axis, and a saw fast on said saw shaft and overlying said turntable.

2. A device as in claim 1 including means for adjustably moving both said grinder shaft and said saw shaft into and out of parallel relationship with said first axis.