US3753430A

US3753430A - Saw-grinder combination for thin rock section machines

Info

Publication number: US3753430A
Application number: US00262695A
Authority: US
Inventors: E Oas
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-06-14
Filing date: 1972-06-14
Publication date: 1973-08-21
Anticipated expiration: 1990-08-21

Abstract

A combination sawing and grinding instrumentality supported on a single arbor for the cutting and grinding of specimens into thin sections for microscopic analysis. An abrasive periphery of the saw is supported against dishing during cutting operations by cooperating plate and grinder means oppositely disposed on the blade. Importantly, the offset grinder means additionally serves to abrade the specimen to the required 30 micron thickness all in one operation without the use of a separate machine and without re-mounting of the slide mounted specimen.

Description

United States Patent 11 1 1111 3,753,430

Oas Aug. 21, 1973 [54] SAW-GRINDER COMBINATION FOR THIN 3,127,887 4/1964 Metzger 51/206 R X C SECTION MACHINES 635,753 10/1899 Diaz 51/206 R X [76] Inventor: ggilOas, Rt. 2, Box 133, Springfield, Primary Examiner Donald G. Kelly Attorney-James D. Givnan, Jr. [22] Filed: June 14, 1972 21 Appl. No.: 262,695 ABSTRACT A combination sawing and grinding instrumentality 52] Cl 1 25/14 51/207 51/209 R supported on a single arbor for the cutting and grinding 25/15 of specimens into thin sections for microscopic analy- [51] Int. Cl B24d-7/18 An r i e periphery of the saw is supported [58] Field of Search...... 51/206 R 206 NF against dishing during cutting by ing plate and grinder means oppositely disposed on the blade. importantly, the offset grinder means additionally serves to abrade the specimen to the required 30 51/206 P, 207, 209 R, 209 DL; 125/13-15 [56] References Cited micron thickness all in one operation without the s u e UNITED STATES PATENTS of a separate machine and without re-mounting' of the 3,289,663 12/1966 Cary 125 13 slide mounted Specimen 2,743,717 5/1956 Wilkin 125/13 3,556,073 1/1971 Garrison 125/14 8 Claims, 6 Drawing Figures E f w FE L2 5 PATENTEI] M1921 I975 SHEET 1l1F2 22 THIN SECTION SAW-GRINDER COMBINATION FOR TI'IIN ROCK SECTION MACHINES BACKGROUND OF THE INVENTION The present invention is embodied within a discoidal structure for mounting on a saw arbor or spindle for the dual function of cutting a rock specimen and grinding same to a reduced thickness providing a very thin rock section of the type suitable for microscopic analysis.

In the field of petrography it is common practice to microscopically inspect a very thin, light transmitting section of rock mounted on a slide using both reflected and transmitted light techniques. Study of the thin rock section under a polarizing microscope enables color identification of the mineral constituency of the rock. The cutting of thin rock sections for such analysis requires extreme precision as variance from a desired thickness will render color indication of the rock constituents extremely difficult. Ideally said rock sections are of a uniform thickness of 30 microns (0.03 mm) for microscopic study.

Typically, such thin rock sections are formed by the cementing of a sawed rock chip, one-quarter inch thick or so, on a glass slide with the slide in turn being mounted on a thin section cut-off saw machine for resectioning of the rock component to an approximate thickness of 0.380 mm. The glass slide with the resectioned rock specimen in place thereon is then typically removed from the saw and mounted on a thin section grinding machine for grinding to the desired thickness of 30 microns.

Various machines are available for performing these sawing and grinding operations including those machines which perform both sawing and grinding operations utilizing a single power source which drives at its opposite ends the individual cut-off blade and grinding wheel. Such machines require remounting of the specimen, and are quite costly by reason of their size and their precise nature in view of the stringent sawing and grinding requirements. In some instances such machines include screw feeds for advancing a rock section against the saw or grinding wheel adding to their cost.

In presently known cut-off and grinding machines, of which i am aware, the slide bearing the rock specimen must be installed at least twice, once for specimen passage past the cut-off saw and again for the grinding operation for reduction of the specimen to the 30 micron thickness. The double mounting effort in combination with different machine slide supporting arms or the like increases the likelihood of a non-constant thickness.

The circular blades used in thin section or cut-off machines are one of several types of blades known in the art as diamond blades and include those termed notched" blades, continuous rim blades and segmented blades all having diamond particles secured about their perimeters by bonding matrixes termed resinoid, metal and vitrified. Such blades are usually of relatively thin metal and hence are susceptible to dishing or deflection when the rock specimen is advanced at other than a very slow rate. The dishing of a blade results in the sawed rock section having a non-constant thickness and accordingly, sawed sections sewn on present thin section cut-off saws must be of excessive thickness to insure at least a minimum thickness of the desired 30 microns. Obviously, the closer the sawn section may be to the 30 micron thickness the less grinding will be necessary and loss of the specimen material.

Blade diameters commonly range from 6 inches on up to 24 and 36 inch diameters with some cut-off machine blades being stabilized by some sort of blade guidance bearing against the blade sides adjacent the blade pe- SUMMARY OF THE INVENTION The present invention is embodied within a power driven instrumentality mounted on a single arbor bearing both rigid cutting and grinding surfaces for the accurate forming of thin sections of rock or other specimens for later microscopic analysis. While the present invention is described with reference to petrography other uses for such a device will become readily apparent to those skilled in the arts of dentistry, orthopedics, electronics and biology to name a few where micro scopic analysis of extremely thin material is routinely performed.

The circular saw-grinder structure shown and described includes a blade component about the periphcry of which, and in common with known like cut-off saw blades, is of the diamond abrasive type which may be applied in the course of blade manufacture in a variety of known methods. The instant invention is not limited to one particular style of abrasive attachment but rather may utilize at its periphery any one of the available blade-abrasive cominations e.g., continuous rim, segmented rim, notched rim and bonding matrixes.

inwardly spaced from the abrasive periphery of the structure are grinding means disposed so as to progressively engage the rock specimen with the cutting and grinding being performed with but one machine and with but one installation of the slide mounted specimen thereon. Heretofore, at least two distinct operations were-necessary with two mountings most usually on individual sawing and grinding machines.

The blade and grinding components of the instant invention, in addition to expediting the forming of thin rock sections, cooperate to overcome the problem of dishing or deflection of the blade during cutting. in a conventional circular saw the blade is reinforced against dishing by smaller diameter plates or flanges, ordinarily one fourth of the blade diameter. The effectiveness of such plates is reduced by reason of their necessarily small diameter such being necessary in order that the blade have a clean, largely unobstructed side surface passing in an are through the material. in the present structure the grinding means, in addition to importantly grinding the specimen, contributes to blade stability. Said grinding means, in conjunction with an oppositely disposed plate, reduces saw dishing to a neglible degree.

BRIEF DESCRIPTION OF THE DRAWINGS With attention to the accompanying drawings:

FIG. 1 is a side elevational view of a machine for forming thin rock sections equipped with a saw-grinder combination structure embodying one form of theinstant invention,

FIG. 2 is a vertical section view taken along line 22 of FIG. 1 showing the saw-grinder structure of the instant invention,

FIG. 3 is a sectional view of the saw-grinder combination taken along line 3-3 of FIG. 2,

FIG. 4 is a schematic showing in edge elevation a glass slide with a rock specimen, cemented thereon, part way through a grinding operation wherein approximately one-half of the rock section has been reduced to a thin section,

FIG. 5 is a composite perspective view, from left to right, of a slide mounted rock chip, a sawn rock section and the finished thin section, and

FIG. 6 is a composite view of modified forms of sawgrinder combinations in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With continuing reference to the accompanying drawing wherein applied reference numerals indicate parts similarly identified in the following specification, the reference numeral 10 indicates generally the sawgrinder structure mounted for powered rotation on an arbor 11.

A typical saw machine includes an electric motor 12 mounted by means of its base 13 to a machine base B on which is also mounted an arbor bearing support at 15. For the purpose of holdinga conventional slide mounted rock specimen for presentation to the sawgrinder combination an arm at 16 is journalled for both arcuate and longitudinal travel will respect to a supporting bar 17. An exemplary arrangement for longitudinally advancing arm 16 is disclosed in the form of a knurled wheel 18 with advancing movement of the arm being against a compression spring 20 retained at its opposite end by a stop 21. The arm 16 terminates downwardly in a boss 16A corresponding to the outside diameter of bar 17 for precise pivoted movement about the axis of the latter during a cutting and grinding operation against the motor driven saw-grinder structure 10.

The arm 16 is adapted to mount a glass slide 22 for movement in a plane parallel to a plane containing the saw-grinder structure 10. Adjustable means 23 on the arm enable the plate to be temporarily secured within a recessed area in the arm. Typically, plate mounting structure on existing machines provides for the temporary mounting of various sized glass slides such structure not being important to an understanding of the present invention no further description of same is believed necessary. The structure above described is not dissimilar to that found in existing cut-off saws and thin section grinders.

With particular attention to FIGS. 2 and 3 wherein one form of the present invention is shown, a circular blade component is indicated at 24 having a peripheral rim portion 25 of diamond particles held within a matrix for cutting of the specimen by abrading. As earlier noted a variety of edge styles is provided by different blade manufacturers for the securement of the diamond particles to the blades peripheral margin all being suitable for such use in the present structure. Blade thicknesses, while not important to the present invention, may range from approximately 0.030 to 0.060 of an inch increasing with blade diameter.

Located on the arbor side of blade 24 are circular plate means 26 which is apertured at its center at 26A for reception of the reduced end of arbor 11. A central recessed area 27 of the platereceives a washer and nut combination at 28. Blade 24 is accordingly reinforced on its arbor side against dishing (deflection).

Oppositely disposed from plate means 26 on blade 24 and inwardly spaced from blade edge 25 are grinder means 29. A peripheral marginal edge 30 of the grinder means is contiguous with blade 24 and embodies diamond particles suitable bonded to the main discoid portion 29 of the grinder in a manner not unlike that earlier mentioned for blade 24. Peripheral marginal edge 30 embodies a first abrading surface 30A and a second abrading surface at 30B operable respectively to reduce the rock section by grinding along perpendicularly related surfaces. A series of equidistant pins 32 extend through corresponding apertures in blade 24 terminating within aligned openings 32 formed in plate 26. Removable attachment means are indicated at 33 in the form of flat head threaded fasteners in counter sunk engagement with circular portion 29 of the grinder which removal permits separation of the saw and grinder components for replacement or servicing purposes. Altematively,the grinder means 29 may be removed, reversed and re-applied to the blade 24. The fasteners 33 are inset somewhat from the surface of grinder body 29 so as not to be exposed even after war has occurred thereon.

With attention to FIG. 4, a thin section is shown partially formed by thepassage of grinder edge 30 approximately halfway through the slide mounted specimen S. The peripheral surface 30A of grinder edge 30 provides a first grinding surface which, ineffect, performs a step grinding operation on the specimen as seen in FIG. 4 with subsequent grinding action (in the nature of a lapping operation) being accomplishedby the marginal surface 30B extending immediately inwardfrom said edge.

Additionally, the grinder means 29 provides an additional function of rigidity supporting juxtaposed rotating blade 24 to support same against dishing during cutting.

With attention being directed to FIG. 6 wherein modified forms of saw-grinder structures are indicated generally at 40, 50, 60 and 70, the first modification at 40 comprises a saw blade 41 having a diamond edge 42 of the general type earlier described. Secured as by an annular weld 43A to the outer surface of blade 41 is a grinder core 43 of annular configuration. Fused to core 43 are diamond particles held in place by a suitable matrix 44 and providing a first grinding surface 44A. A surface at 448 constitutes a secondary grinding surface. In similarity to the first described embodiment a plate 45 is apertured at 46 to receive the end of a spindle 47 with a nut element 48 affixed to the spindle end and bearing against the apertured blade 41 to confine same and plate 45 in place on the reduced and of the spindle. In this embodiment of the invention the working surface of the grinder may be refurbished as may the cutting edge 42 of the saw blade.

The modification indicated generally at 50 includes a saw blade at 51 with a diamond particle abrasive periphery 52, the blade including a thickened central portion or base 53 on and about which is fused a diamond embedded matrix 54 having a first grinding edge 54A and a secondary grinding surface at 543. Again perpendicular, contiguous working surfaces are provided for step like grinding of the previously cut rock specimen. A plate at 55 serves to reinforce blade 51 against deflection as in the earlier forms of the invention and in continuing similarity is centrally apertured at 56 for spindle attachment with retention thereon being by nut element 58 on the spindle end 57.

Indicated at 60 is yet another modified form of the invention comprising a blade 61, having a cutting edge 62, the blade being of ring-like configuration brazed or otherwise suitably secured at 63 along its inner diameter to a plate 64. A diamond bearing matrix 65 provides a first grinding surface at 65A and is secured as by fusing to a shouldered, irregular surface 66 of plate 64. A secondary grinding surface is indicated at 65B. A nut element 67 received within a central recess 63A of the plate retains same on a spindle end 68.

Indicated generally at 70 is still another form of the instant invention wherein a balde 71, having a diamond cutting edge 72, is of annular configuration for placement about a plate member 73. A blade retainer ring at 74 is secured at intervals to plate 73 by means of threaded fastners 75 with the fasteners and ring being removable from plate 73 to permit axial removal of blade 71. Studs, one of which is indicated at 74A project inwardly from the inner surface of ring 74 for keyed engagement with openings 71A in the blade. Grinding means is embodied within a diamond supporting matrix at 76 having a peripheral edge 76A which extends outwardly beyond its supporting plate 73 with a secondary grinding surface indicated at 76B. Plate 73 is recessed at 73A for the purpose of receiving a nut element 78 retaining the saw-grinder structure on a spindle end 79.

While I have shown and described but a few embodiments of the invention it will be apparent to those skilled in the art that the invention may be embodied still otherwise without departing from the spirit and scope of the invention.

Having thus described the invention what is desired to be secured under a Letters Patent is:

l. A combination saw-grinder structure for attachment to one end of a saw arbor for sequential cutting and grinding of a specimen into a thin section during unidirectional closing movement of the specimen with said structure for later microscopic analysis, said sawgrinder structure comprising,

a circular blade,

grinder means centrally mounted on said blade and spaced inwardly from the blade cutting edge, said grinding means including a first abrading surface embodied within a peripheral wall contiguous with one sidewall of the blade, a second abrading surface normal to said first abrading surface extending radially inward from said first abrading surface whereby upon closing movement of the sawgrinder structure and the specimen the latter is initially sawn by the blade to a desired thickness with subsequent grinding of the specimen to the desired thin section thickness by said first and second abrading surfaces all being accomplished in one pass of the specimen past the saw-grinder structure.

2. The combination saw-grinder structure as claimed in claim 1 additionally including plate means of lesser diameter than said blade and carried by the saw arbor, said plate means serving to support said blade and abrading surfaces against deflection during sawing and grinding operations.

3. The combination saw-grinder structure as claimed in claim 2 additionally including fasteners interconnecting the grinder means and said blade removably mounting said grinder means to said blade permitting detachment for repair and replacement purposes or reversal of said grinder means.

4. The combination saw-grinder structure as claimed in claim 2 additionally including pins carried by said grinder means extending through said blade and terminating within said plate means.

5. The combination saw-grinder structure as claimed in claim 2 wherein said grinder means additionally includes an annular core secured to said blade.

6. The combination saw-grinder structure as claimed in claim 2 wherein said blade is formed with an annular central portion of greater thickness than the adjacent blade portion, said annular central portion of the blade constituting a supporting base for said abrading surfaces.

7. The combination saw-grinder structure as claimed in claim 2 wherein said blade is of annular configuration, said plate being concentrically disposed within said annular blade and secured thereto, said plate projecting outwardly past one side of the blade to thereat support said first and second abrading surfaces.

8. The combination saw-grinder structure as claimed in claim 2 wherein said blade is of annular configuration circumposed about said plate, said saw-grinder structure additionally including a blade retainer also circumposed about said plate, means removably mounting said retainer to said plate permitting blade removal, said plate projecting outwardly past one side of the blade to thereat support said first and second grinding surfaces.

Claims

1. A combination saw-grinder structure for attachment to one end of a saw arbor for sequential cutting and grinding of a specimen into a thin section during unidirectional closing movement of the specimen with said structure for later microscopic analysis, said saw-grinder structure comprising, a circular blade, grinder means centrally mounted on said blade and spaced inwardly from the blade cutting edge, said grinding means including a first abrading surface embodied within a peripheral wall contiguous with one sidewall of the blade, a second abrading surface normal to said first abrading surface extending radially inward from said first abrading surface whereby upon closing movement of the saw-grinder structure and the specimen the latter is initially sawn by the blade to a desired thickness with subsequent grinding of the specimen to the desired thin section thickness by said first and second abrading surfaces all being accomplished in one pass of the specimen past the saw-grinder structure.