US1244939A - Grinding and polishing tool for bifocal lenses. - Google Patents

Description

Patented Oct. 30, 1 917.

ans

CLILE C. ALLEN, OF CHICAGO, ILLINOIS, ASSIGNOB, MESNE ASSIGNMENTS, TO NEW YORK LENS COMPANY, INC., 03 NEW YORK, N. Y., 13 GOBEOB-ATION 01 NEW YQRK.

GRINDING- AND POLISHING TDOL FOE BIFOCAL LENSES.

Application filed February 1a, 1913, Serial as.

To all whom it may concern:

Be it known that I, CLILE G. A EN, a citizen of the United States, residing at Chicago, in the county of Cook. and State of Illinois, have invented, certain new and useful Improvements in Grinding and Polishing Tools for Bifocal Lenses, of which the following is a specification.

This invention relates to tools for grinding and polishing bifocal lenses wherein the lens is provided upon one surface with two areas ground to two different radii of curvature.

It is the object-0f the present invention to provide a grinding lap which will simultaneously grind a plurality of lenses creating two areas upon one surface of each lens, having different radii of curvature, and also to provide a means for finishing and polishing said lenses, eliminating any tendency to inequality or zonal difierences.

With the above and other objects in view, this invention consists in the construction, combination and arrangement of parts all as hereinafter more fully described, claimed and illustrated in the accompanying drawings, wherein Figure l is a longitudinal section of the polishing tool forming the subject matter of the present invention, cooperating with the holder and the lens;

Fig. 2 is a section taken along the line 2-2 of Fig. 1, illustrating the cotiperation between the polishing disks and the lens surface;

Fig. 3 is a face view of the holder of the polishing tool showing the plungers upon which the polishing disks are mounted, in section, and illustrating the adjustment of said plungers.

The lens holder 14, which is oppositely disposed to the grinding face of the lap, is cup-formed, to receive the lens blank 15,

which is retained at the hollow end of said holder by means of cement, indicated at 16.

The holder 14 is shown as being mounted in the head stock of a lathe, while the grinding or polishing laps are mounted in the tail stock, as illustrated in Fig. 1 but it will be understood that it is unnecessary to use such a construction for imparting the necessary rotation to the elements, as any suitable Specification of Letters Patent.

"ice,

Patented Oct. 30, 191

823. Renewed Earch 29, 1917. Serial No. 158,436.

means could be provided'for rotating the elements about the same axis.

The polishing or grinding tool comprises a cylinder 18, closed at one end by the block 19, which is inserted in said cylinder by any suitable process and which carries means for supporting said holder, such as the tapered shank 20. The opposite end of the cylinder 18 is provided with a block 21, which is inserted therein and which is provided with a plurality f passages22 adjacent to the periphery thereof and with a central passage 23, said passages being circular inv cross section and arranged upon parallel axes. Over the terminal. of each outer passage 22 is pivotally mounted a plate 24, through the medium of the screws 25, said plates adapted to swing about said screws as their piaotal points over the outer terminals of therpassages 22. Each plate is provided at its outer terminal with a slot 26, through which a fastening device such as a screw 27 is inserted and pierces the face of the block 21. By means of the screws 27 coiiperating with the slots'26, the plates are retained in any of their various adjusted positions. Registering with the passages 22 are openings piercing the plates 24, through which plungers 28 extend. These plungers 28 extend into the passages 22 and are provided adjacent to the plates 24 and within said passages with the transverse pins 29. Springs 30 are interposed between the pins 29 and the inner face of the block 19 and tend to force the plungers 28 in an outward direction. It will readily be seen that as the plates 24 are adjusted, the plungers 28 wild assume various adjusted positions. A plate 31 is pivotally mounted upon a screw 32 adjacent to the central passage 23, and; is also provided with a slot 33, pierced by a screw 34, which enters the outer face of the block 21. This plate is, therefore, adjustable in a manner similar to the plates 24 and is also provided with an openingregistering with the passage 23, through which the central plunger 35 passes; This central plunger 35 is also provided withthe ,pin 36, against which a spring 37 bearsg zithe opposite terminal of said spring bearing against the inner face of the block 19.

The outer terminals of the plungers 28 and the plunger are provided with the balls 38, by means of which the polishing or finishing disks 39 are mounted upon said plunger-s.

The grinding or polishing disk 39 carried by the central plunger 35 contacts with the inner area of the lens blank 15, while the outer polishing disks 39 carried by the plungers 28 bear against and coiiperate with the outer area. It will be seen byreference to Fig. 2 that the polishing disks 39 and the lens 15 rotate in the same direction, and that the outer polishing disk adjacent to the outer portion of the lens 15, rotates with the lens, while the inner portion thereof adjacent to the central area of the lens rotates against polishing disk 39 and the outer polishing disks 39 are always concentric at each and every point of the rotation of the lens. Consequently,-the line of demarcation between the two surfaces of the lens is produced. The bearing faces of the polishing disks are provided with the same curvature as the lens surfaces desired. By the provision of the plates 24 and 31, the various plungers and consequently the polishing or grinding disks may be adjusted to any suitable correlation.

From the foregoing, it will be understood that two bifocal lenses may be simultaneously ground and polished, at the same time eliminating zonal differences and creating. a definite and fixed line of demarcation between the focal areas of each lens without creating a shoulder or projection. After the' lenses have been ground and polished, the lens blank is then cut, producing the lenses therefrom. I Y By the arrangement of-the polishing disks 39 with the central disk out of alinement with the outer disks, the center disk rotates with the lens blank 15 to polish the center of the inner focalarea as well as the periphcry of the inner focal area. By the provision of two polishers of various sizes, arranged to coiiperate with the central focal area of the-lens .blank 15, the center of the focal area operated upon will be given the proper grinding action by one of. the disks, while the portion of the focal area adjacent to the periphery thereof will also be given the proper.

grinding action, which grinding action, however, will be difierent than the grinding action of the center of thefocal area, due to ranges the difierence in size of the disks. in other 3 words, one disk, as illustrated, may be used to operate upon the central focal zone of the lens blank 15, or any number of disks maybe used. It will further be understood thatany number of disks may be used to operate upon the outer focal area of the lens blank 15.

lhe polishing of a lens is in practice nothing but refined grinding, and hence, to use the tool illustrated for the purpose of grinding the lens the polishing elements or disks 39 are removed from the plungers 35, and grinding disks of suitable texture and formation are substituted therefor. I After these grinding disks have created or formed the proper focal areas of the lens blank 15, they are removed from the plungers 35 and the polishing disks 39 replaced thereon to opcrate in the manner heretofore described.

What is claimed is:

1. The combination of a holder; plates secured to said holder and adapted to be adjusted independently of each other on said holder, there being a perforation in each plate and a plunger slidably mounted in and snugly fitting each of said perforations.

2. The combination of a holder; plates pivoted to said holder, there being a perforation in each of the plates; means locking the plates against pivotal movement of said holder; and a plunger slidably mounted in and snugly fitting each of said perforations.

3. The combination of a holder; plates pivoted to said holder, there being a perforation in each of the plates; screws threaded in said holder and engaging said plates locking the latter in difierent positions of their pivotal movement; and a plunger slidably mounted in and snugly fitting each of said perforations.

4. The combination of a holder; plates pivoted to said holder, there being a perforation and a slot in each of said plates; a screw passing through each of said slots, said screws locking said plates in difi'erent positions of their pivotal movement; and plungers slidably mounted in and fitting said perforations.

5. The combination of a holder; plates pivoted to said holder, there being a perforat1on and a slot in each of said plates; a screw passmg through each of said slots, said screws locking said plates in different positions of their pivotal movement; plungers slidably mounted in and fitting said perforations; and a compression spring on each of said plungers, each of said sprmgs havmg one of its ends slidably engaging said holder.

6. The combination of a holder; plates pivoted to said holder, there being a perforation in each of the plates; means locking the plates against pivotal movement on said holder; and a plunger slidably mounted in and snugly fitting each of said perforations two subscribing witnesses, on this 14th day and extending into said holder; and a comof February, A. D. 1913. presslon spring on each plunger in said holder with 0ne end of the sprmg slidably CLILE C. ALLEN. 5 engaging a portion of the holder. Witnesses:

In testimony whereof I lhave signed my CHAS. S. WILSON, name to this specification, in the presence of DWIGHT B. CHEEVER.

copies of this patent may be obtained tor five cents each, by addressing the "Commissioner d Patcntl,

. Washington, D. 0.

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