US2779137A - Mirror grinding machine - Google Patents

Description

Jan. 29, 1957 F. T. GRISCAVAGE 2,779,137

MIRROR GRINDING MACHINE Filed Sept. 21, 1954 2 Sheets-Sheet l INVENTOR "Ill/11111115! ATTE IRNEYS a i Tm w 2 3 V JIM u 7M! 014; 5 cl a m 1 r C A 1, I I L; a m j a 1 W a m 1957 F. T. GRISCA'VAGE MIRROR GRINDING MACHINE 2 Sheets-Sheet 2 Filed Sept. 21; 1954 INVENYOR. frank I griscava' e ATTD RN EYS United States Patent-'0 MIRROR GRINDING MACHINE Frank Thomas Griscavage, Wilkes-Barre, Pa.

Application September 21, 1954, Serial No. 457,429

1 Claim. (Cl. 51-123) This invention relates to machines for grinding mirrors, lenses, and flat pieces of material in which discs for form ing mirrors and the like are oscillated over tools with an abrasive or other grinding or polishing substance positioned between the tools and discs whereby surfaces are finished to millionths of an inch precision.

The purpose of this invention is to provide means for oscillating discs in relation to tools or tools in relation to discs whereby mirrors, lenses, and the like are adapted to be accurately finished and polished.

In the conventional method of grinding mirrors and large optical elements by hand, the grinding operation includes rubbing one glass disc on top of another with abrasives and water between the discs, the upper disc being moved back and forth over the tool and rotated to the left with the result that the same spot on a disc never comes in contact with a similar spot on the tool and by this means the upper disc is provided with a concave surface with the lower tool having a convex surface. By this method an extremely even grind and polish is obtained, the surfaces being precision finished and being accurate by a millionth of an inch.

With this thought in mind, this invention contemplates a mechanical device for oscillating discs over tools or tools over discs, such as mirrors, lenses, and flats whereby accurate grinding and polishing is accomplished and wherein the elements may readily be removed for adding abrasive and the like, and replaced. p

The object of this invention is, therefore, to provide means for mounting and operating a reciprocating frame with offset pushers therein whereby with the tools or discs positioned in openings in the frame discs or tools are caused to rotate and slide over corresponding elements with the moving elements continuing to rotate in the same direction.

Another object of the invention is to provide a machine for grinding and polishing optical elements in which parts are oscillated over corresponding parts in which the upper parts are adapted to be removed for adding abrasive and the like between the elements, and replaced.

Another object of the invention is to provide a reciprocating frame with oifset elements positioned in pockets therein for oscillating elements in the pockets over tools, discs, and the like in which means is provided for controlling the length and speed of the reciprocating strokes.

A further object of the invention is to provide a machine for accurately grinding and polishing optical elements in which the machine is of a simple and economical construction.

With these and other objects and advantages in view, the invention embodies a plurality of turntables rotatably mounted in a frame with tools positioned on the turntables and discs freely slidable n the tools, a frame having pockets therein in which the discs are positioned and having offset disc-engaging elements in the pockets and an operating transmission for reciprocating the frame and rotating the turntables.

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Other features and advantages of the invention will appear from the following description taken in connection with the drawings, wherein:

Figure 1 is a plan view illustrating a typical arrangement of the machine.

Figure 2 is a typical longitudinal section through the machine illustrating the reciprocating and rotating elements, the discs and tools being shown concave and convex, as finished.

Figure 3 is a plan view of one corner of the reciprocating frame with the parts shown on an enlarged scale andillustrating the oscillating path through which a disc positioned on a tool travels.

Figure 4 is a cross section through one side of the reciprocating frame being taken on line 4-4 of Figure 1 illustrating the arrangement of the rails and tracks and with the parts shown on an enlarged scale.

Figure 5 is a cross section taken on line 5-5 of Figure 3 illustrating the free mounting of the filler partitions in the frame.

Figure 6 is a detail illustrating the mounting of one of the disc-moving elements or pushers.

Figure 7 is a plan view illustrating a modification wherein a tool is mounted to slide or oscillate over a mirror.

Figure 8 is a detail illustrating a typical method of applying a weight to a tool or mirror.

Referring now to the drawings, wherein like reference characters denote corresponding parts, the improved mirror grinding machine of this invention includes a frame having a base 10 with a tray 11 supported by uprights 12, turntables 13 on the upper ends of shafts 14 rotatably mounted in bearings 15 in the tray 11, a belt 16 trained over pulleys 17 on the lower ends of the shafts 14, a reciprocating frame having side bars 18 and 19 connected with end bars 20 and 21, a filler including a center partition 22 with transversely disposed partitions 23 and 24 providing pockets in the frame, actuating rollers 25 carried by the transversely disposed partitions, similar rollers 26 carried by the end bars 20 and 21, bumpers 27 carried by the side bars 18 and 19, bumpers 28 carried by the center partition 22, the rollers and bumpers of the individual pockets being diametrically opposed, and suitable transmission elements for reciprocating the frame and rotating the turntables including a pitman 29 adjustably mounted by a bracket 30 on a pulley 31, a gear housing 32, a reduction gear 33, a motor 34, and suitable mounting and connecting elements.

As illustrated in Figure 1, the motor 34 drives the reduction gear 33 through a belt 35 which is trained over a pulley 36 on the motor shaft and a pulley 37 on a reduction gear shaft 38. The gear housing 32 is actuated by the reduction gear unit 33 with a shaft 39 and the pulley or drum 31 is carried by a shaft 40 that is extended from the housing 32.

The bracket 30, which is shown particularly in Figure 2, is provided with an elongated slot 41 through which a bolt 42 that clamps the bracket on the drum or pulley 31 extends.

The pitman 29 is connected to the bracket 30, at one end, with a ball and socket joint 43 on the end of an arm 44 and the opposite end is connected to the end bar 21 of the reciprocating frame with a ball and socket joint, as indicated by the numeral 45.

The belt 16, for rotating the turntables, is driven from the drum 31 with a belt 46 trained over the drum and also over a pulley 47 on a shaft 48 rotatably mounted in bearings 49 and 50 and provided with a worm 51 that meshes with a worm gear 52 on a shaft 53 on which a pulley 54, over which the belt 16 is trained, is mounted. The shaft 53 is rotatably mounted in a bearing stand 55 which Patented Jan. 29, 1957 is secured to the base 10 ofthe housing or frame with bolts 56 which extend through a base 57 of the stand.

The belt 16 is trained over an idler pulley 58 on a bearing stand 59 and also over the pulleys 17 on the shafts 14, the pulleys 17 being retained on lower ends of the shafts 14 with nuts 60 and Washers 61.

By this means, the horizontally disposed frame is reciprocated and the turntables are rotated slowly and, as illustrated in Figure 3, reciprocation of the frame moves the discs over the tools with oscillating movements whereby the discs are moving continuously and registering points of the discs and tools never return to the same positions.

The discs are actuated by the rollers 25 and 26 and with the parts, as illustrated in Figure 3, longitudinal movement of theframe causes the roller 25 to engage a disc, such as disc 62 with the disc moving over atool 63' and engaging the bumper 28. With continuous movement of the parts, the disc 62 moves to the position indicated by broken line 64 and with return movement of the frame the roller 26 urges the disc against the bumper 27 whereby the disc is returned to a starting position in registering relation with the tool 63.

The rollers 25 and 26 are carried on arms 65 of brackets 66, the brackets being secured by bolts 67 and nuts 68 to angularly disposed sections 69 of clips 70, the base sections of the clips being secured to the transversely disposed partitions 23 and 24 of the filler with bolts 71 and nuts 72.

The ends of the center partition 22 and transversely disposed partitions 23 and 24 of the filler f the reciprocating frame are freely held in U-shaped brackets 73 with projections 74 of the partitions extended through notches 75 in the brackets with notches 76 in the partitions being positioned in the notches 75. The ends of the brackets 73 are provided with flanges 77 and 78 that are secured to the side and end bars with bolts 79 and nuts 80.

The bumpers 27 and 28 are secured to the bars and partitions with suitable bolts or screws, as indicated by the'numeral 81.

The side bars 18 and 19 of the reciprocating frame are provided with rails 82 having extended flanges 83, the flanges being positioned to slide between spaced flanges 84 and 85 of tracks formed with angle irons 86 and 37, the angle irons being secured to the uprights or posts 12 of the mounting frame, such as by welding, as shown in Figure 4.

The tray 11 is formed with inclined side and end Walls, as indicated by the numeral 88, with filling elements 89 connecting the Walls and tray to end rails formed with angle irons 90 and 91 and to similar side rails 92 and 93. The tray is provided with a drain 94 that is adapted to carry away excess fluid used in grinding the elements.

In the design illustrated in Figure 7, a mirror 95 is positioned upon a suitable turntable and a tool 98 ac tuated over the mirror with an oscillating movement by rollers 99 and 100 on brackets 101 and 102 in a reciprocating frame 103. The brackets 101 and 102 are similar to the brackets 66 and clips 70 and the frame 103 is also provided with bumpers, as indicated by the numerals 104 and 105.

The frame 103 is slidably mounted in rails 106 and 107 and the rail 106 is adjustably mounted by extensions 108 4 and 109 in which elongated slots 110 and 111 are provided, respectively. The rail is secured in adjusted positions with bolts 112. p

The frame 103 is adapted to be reciprocated by a pitman 113, similar to the pitman 29, the pitman being connected to the frame 103 with a ball and socket joint 114.

In the detail illustrated in Figure 8, a mirror 115 is provided with a cover 116 and a layer of material, such as lead as indicated by the numeral 117, may be positioned between the mirror and cover to provide weight to facilitate grinding the lower surface of the mirror with the mirror positioned on a tool such as one of the tools shown in Figure 2.

In starting the grinding and polishing operation all tools and discs are flat on both sides, and mirrors six inches in diameter or smaller must be provided with weights. With continued operation of the machine the upper surfaces of the tools are ground and polished to provide convex surfaces and the meeting surfaces of the discs are ground and polished to provide concave surfaces as shown in Figure 2.

With the assembly of parts, particularly as illustrated in Figure 7, a single tool is illustrated as being actuated with an oscillating movement over a mirror or lens, and it will be understood that instead of the single tool shown in Figure 7, a plurality of tools arranged in a frame forming a battery, as illustrated in Figure 1, may be used and the tools may be assembled in different designs and actuated with an oscillating movement independently or as a complete unit.

The transmission, including the gear reduction 33 and gear housing 32, makes it possible to actuate the discs and rotate the tools at relatively slow speed.

It will be understood that other modifications, within the scope of the appended claims, may be made in the design and arrangement of the parts without departing from the spirit of the invention.-

What is claimed is':

A mirror grinding and polishing machine comprising a turntable, means for rotating the turntable, a tool mounted on the turntable, a disc positioned on the tool, a frame having a pocket therein positioned around the disc, side walls of the pocket being spaced from the periphery of the disc, diametrically opposed rollers mounted on the frame positioned in the pocket and adapted to contact the peripheral surface of the disc, diametrically opposed bumpers also mounted on the frame, positioned in the pocket and adapted to contact the" peripheral surface of the disc, and means for actuating the" frame with an oscillating movement.

References Cited in the file of this patent UNITED STATES PATENTS 1,485,321 Wilkinson Feb. 26, 1924 1,639,012 Tillyer' Aug. 16, 1927 1,972,086 Buckley Sept. 4, 1934 2,246,869 Troendly et al. June 24, 1941 2,398,628 Dykoski Apr. 16, 1946 2,404,282 Fr'uth' July 16, 1946 FOREIGN PATENTS 804,761 Germany Apr. 30, 1951

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