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Sept. 6, 1938. K. c. BURROUGHS 2,129,522 METHOD AND MEANS 'FOR ABRADING LENSES Filed 001;. 9, 1955 KENNETH C. BURROUGHS I INVENTOR BY ' ~ ‘:7 , » Patented Sept. 6, 1938 _ UNITED ‘STATES PATENT OFFICE, 2,129,522 METHOD AND MEANS FOR- ABRADING . LENSES Kenneth C. Burroughs, Rochester, N. Y., assignor to Banach & Lomb Optical Company, Roches ter, N. Y., a corporation of New York Application October _9, 1935, . Serial No.“ 44,24‘! ‘ '6‘ Claims. (Cl. 51-278) This invention relates to the lens grinding and polishing art wherein an abrading tool'or lap tially “the same asthe area of the surface of the lensto be ground or.polishe'd.'., The spindle i4 is is moved over the surfaceof a lens to grind or inclined, as shown in Fig.1, so that thegtool i3 polish it. . _ The invention is an improvement over the in- U! vention disclosed and claimed‘ in application Serial No. 433,934, filed March '7, 1930, by Carl overlies the lens L with the center of rotation of the tool positioned substantially at the edge of in the lens L. , According to the present invention, the tool i3 E. Anderson for a Method and means for abrad- ' is slightly eccentric 0n the Shaft '4 and thus. dur ing lenses, now Patent No. 2,105,175, dated Jan. ing rotation. moves between. the Positions indi 10 11, 1938. It is quite difilcult mechanically to lo- - cated at I!’ and i3" in Fig. 2. As stated above. 10 cats the tool and lens of that application so that when the edge of the tool contacts the center of the edge of the tool passes exactly over the center the lens, and the edge of the lens. the Center Of of the lens. Unless the tool and lens are so 10- the tool, itl'equll‘es great delicacy of adjustment cated, the resultant lens will have either a raised to avoid grinding the center of the lens either 15 spot in the center due to insufficient abrading twice or not at all. By making the tool eccen- 15 20 .25 30 13 5 action, or will have a depressed spot due to double abrading action. The only alternatives disclosed by Anderson for preventing this dimculty, are the accurate positioning of the lens and tool or the oscillating of the tool shaft and tool across the lens. Both of these obviously present mechanical di?iculties. One of the objects of the present invention is to provide a method and means for abrading lenses wherein»v the tool will grind the lens uni~ formly and will be worn away in a substantially uniform manner over its entire area. Another object is to provide a method and means for abrading lenses wherein the tool is prevented from grinding high or low target spots in the center of the lens. These and other objects and advantages reside in certain novel features of construction, arrangement and combination of parts and in my improved method, as will hereinafter be more fully set forth and pointed out in tric on the shaft ll, the amount of abrading 80 tion at the center of the lens can be regulated. It is also possible to obtain the same result by oscillating the shaft ll about the center of curva time during the rotation of the tool- This system. however, introduces difficulties of mechanical construction so that the eccentric positioning of the tool is preferable. The lens L and tool I: are rotated at the same speed in opposite directions, as indicated by the arrows in Fig. 2, or they may be rotated ‘in the same direction. The tool and lens being of sub stantially the same diameter and area and'rotat ing at substantially the same speeds, the abrading action will be uniform over the entire surfaces of the lens and tool. The tool will thus wear away uniformly without losing its curve so that a large number of lenses may be ground without the ne cessity for truing up the tool. _ The fundamental principles underlying the the appended claims. _ Referring to the drawing: present invention are substantially the same as those underlying the invention disclosed in the . _ ' Fig. 1 is a sectional view of an apparatus embodying my invention. -i() Fig. 2 is a schematic diagram illustrating the overlapping relation between the tool and the lens. One embodiment of this invention is illustrated in the drawing wherein L indicates a lens blank 45 which is to be operated upon. The blank L is v. mounted, by any suitable means, upon a block or am able to attain the objects of my invention and provide improved method and means for abrading lenses wherein the tool will grind the or other means through the pulley IS. The diameter of the abrading tool I3 is sub- stantially equal to the diameter of the lens L so 55 that the area of the abrading surface is substan- 25 30 35 above-mentioned application, Serial No. 433,934 ?ied March '1, 1930 by Carl E. Anderson, for a Method and means for abrading lenses. Accord- 40 ing to the present invention, however, the abrad ing tool is mounted eccentrically and the necessity of delicate or changing adjustments of the posi tion of the tool, avoided. From the foregoing it will be apparent that I 45 chuck l0 which is carried by a spindle II and adapted to be rotated through the application of suitable power to the pulley ii. A suitable 0 abrading tool or lap i3 is carriedby the spindle it so that it may be rotated or driven by a belt 20 lens uniformly and will be worn away in a sub stantially uniform manner over its entire area. 50 Various modifications can, of course, be made without departing from the spirit of my inven tion or the scope of the appended claims. ' _I claim: 1. A method of abrading lenses which com- 55 2,129,522 prises rotating an abrading tool in contact with 4.'Lens grinding means comprising a spindle a lens having substantially the same diameter carrying a block for supporting a lens, a second as the abrading surface of the tool, holding said tool eccentrically with its abrading surface contacting said lens and with the center of rotation of the tool positioned ‘substantially at spindle mounted above the ?rst spindle and in angular relation thereto, an abrading tool eccen trically ?xed to said second spindle, said tool having a substantially continuous spherical sur the edge ofthe lens, and rotating said lens at face whose area and diameter are substantially substantially the same speed of rotation as the the same as the area ‘and diameter of the lens, tool. 2. A method of abrading a lens having a said tool being positioned in contact with the lens with its center of rotation substantially at the edge of said lens and means for rotating said spindles at substantially the same speeds. 5. A method of abrading lenses which com prises placing a tool in contact with a lens, rotat ing said tool about an axis which is eccentric 15 to said tool and which passes adjacent the edge of said lens and rotating said lens at substantially substantially spherical surface which comprises placing in contact with said surface an abrading tool having a spherical surface which has sub-. stantially the same diameter and area as the sur face of the lens, rotating said lens about an axis concentric with said lens and rotating said tool at substantially the same speed as said lens about an axis eccentric to said tool, the axis of rotation of said tool lying substantially in a 21 the same speed as said tool. carrying shaft, means for mounting a lens con centrically on said shaft, a tool carrying shaft 6. A method of abrading lenses which com prises placing a tool in contact with a lens, rotat 20 ing said tool about an axis which is eccentric to said tool and which passes adjacent the edge of said lens and rotating said lens at substan-. positioned with its axis substantially at the edge tially the same speed as said tool about an axis line passing through the edge of said lens. 3. Lens abrading apparatus comprising a'lens 25 of ‘said lens, a tool having substantially the same area and diameter as said lens, means for mounting said tool eccentrically on said tool carrying shaft, and means for rotating said two ‘shafts at substantially the same speed. which is concentric to said lens. KENNETH C. BURROUGHS.