US2271334A - Lens grinding machine - Google Patents

Description

Jan. 27, 1942. R. E. FOSDICK LENS GRINDING MACHINE Filed Aug. 25, 1938 3 Sheets-Sheet 1 INVENTOR 205527 E FOSQLCK.

BY A

Q an R mu ATTORN EYS s Sheets-Sheet 2 Filed Aug. 25, 1938 INVENTOR EIZT .F'OSD K ATTORNEYS Jan; 27, 1942. R. E. FOSDICK LENS GRINDING MACHINE Filed Aug. 23, 1958 3 Sheets-Sheet 3 INVENTOR 7 eoamr Ef'OJD/CK W [W H L l l lu ATTORNEYS Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE- LENS GRINDING MACHINE Robert E. Fosdick, Dayton, Ohio Application August 23, 1938, Serial No. 226,354 6 Claims. (01. 51-67) This invention appertains tothe art of grinding lenses and more particularly to the provision of an automatic machine for this purpose having provision for various types of adjustmentwhereby any desired sort of lens grinding operation may be accomplished with facility, accuracy and while an abrasive block is held thereagainst and,

moved backward and, forward over the surface to be ground. This is an operation requiring great skill of an operator so engaged, involving the factors of speed of rotation of the lens glass, the pressure with which the abrasive is held thereagainst, the speed of reciprocating movement of the abrasive across the surface to be ground, and the uniformity of this reciprocating movement. In the hand operation of lens grinding the results of these factors are dependent entirely upon the skill of the operator, and under most favorable conditions accuracy and miiformity of results is an object most difficult to achieve.

It is, therefore, an object of the present invention to secure these desired results by the provision of a machine in which the human element controlling the factors above mentioned is to a great extent eliminated, and by means of which uniform results are obtained automatically in accordance with certain initialadjustments It is a further object of the invention to provide a machine of the type set forth having provision for a variety of adjustments whereby to enable the same to perform any desired lens grinding operation.

A still further object of the invention is to provide a machine which will duplicate any hand operation. of lens grinding but with greater accuracy and uniformity than heretofore possible.

While it is impossible, of course, to eliminate entirely the human element, or requisiteskill of an operator to perform, satisfactorily, special lens grinding operations, such as those for which the present invention has been designed, it isthe aim and actual accomplishment of the instant invention to confine the need for such skill to initial adjustments of the operating parts of the machine, which then performs uniformly and accurately in accordance therewith. Once initial adjustments are made, the skill of the operator is mainly relied upon to determine the extent to required, and, of course, the ability of an operato to make proper adjustments is essential.

In carrying out the practice of the invention '1 providea machine comprising means for revolvin accordance with a variety of adjustments of adjustable ,means provided for this purpose, means for reciprocatingthe abrasive holding deviceacross the surface of the lens glass, means for adjusting the length of stroke of the reciprocating means, and'means for reciprocating the same atdifierent rates of speed. The various motions for accomplishing the above. objects and purposes are produced from a single source of power.

' Other objects, advantages and features .of novelty will appear more fully as the description of the invention progresses in' conjunction with the drawings and as defined in the appended claims. In the drawings: ,I Y I Figure 1 is a top plan view of the reciprocating means and ancillary parts.

Figure 2 is an end elevation looking in the direction of the arrows 2-2 of Figure 1. j

speed, means for holding an abrasive substance at varying degrees of pressure against the lens glass Figure 3 is a side viewof a portion of a machine embodying the invention, the same Particularly-showing the relation of parts which hold and act upon the lens glass to be ground, and their relation to their respective operating instrumentalities. r v

I Figure-4 is a view contiguous to Figure 3, being a side view of a portion of the machine illustratedin Figure 3, showing more particularly the operating instrumentalities.

Figurev 5'is an end view of the machine illustrated in the foregoing figures, illustrating the relation of the instrumentalities shown in Figure 4.

Referring now to the-embodiment of the invention shown in the accompanying drawings, the same generally comprises a frame A, theupper portion of which forms a table B upon which is supported a carrier bracket C to which isadjustably secured a reciprocating arm D carrying an abrasive block E. In the lower part of the frame is'mounted a source of power F which, through instrumentalities later to be described, drives the eccentric shaft G, for reciprocating. the arm D, and the main spindle H towhich latter is splined the lens block or carrier I.

Figures 3 and 4 are contiguous, the former showing the instrumentalities positioned above the table B and the latter showing those instrumentalities positioned below the table B;

Structure For the present Figures 4 and 5 will be more particularly referred'to. I

'Themotor F is carried by a bracket l suitably secured to base Z'of the frame A, and to its drive shaft 3 is fixed a pulley 4. A belt 5,'trained over pulley l' and a second pulley 6 fixed to the main drive shaft 1, enables said shaft 1 to be driven by the motor. Theshaft is journaled in bearings 8 and 9 carried by brackets l0 and II respective- 1y which are secured to upright members l2 and |3 respectively of the frame A.

Fixed to the drive shaft 1 is a step-pulley l4. A belt I5 is trained thereover and also over a step-pulley Hi, the latter being fixed to a driven shaft I! by means of a key l8 engaging the key-way H] of said shaft Shaft IT is journaled in bearing cross-members 20 and 2|. secured to the base 2 of frame A and also extends through passages 22 and 23 of a slide member K. Shaft also carries at one end a roller 24 which is in driving engagement with the friction disc 25 fixed to the main spindle H.

The slide member K is movable from left to right, referring to Figure 4, in a guide-way 2'! carried by a bracket 28 bolted to the base 2 of frame A. Said slide member K has an internally threaded passage 29 which receives the threaded end 39 of screw shaft 3| rotatably journaled in a bearing cross member 32 secured to upright member I3 of frame A. Said screw shaft 3| is prevented from horizontal movement by a collar 33 fixed thereto which is positioned against said bearing 32. Exteriorly of the frame A there is secured to said screw shaft 3| an operating wheel or member 34.

The speed at which the main spindle H is rotated is regulated by operation of the screw shaft 3| rotated by the wheel 34. Rotation of the screw shaft 3| causes leftward or rightward movement, referring to Figure 4, of the slide member K by cooperation of the internally threaded passage 29 thereof with the threaded portion 39 of said screw shaft 3|. Movement of slide member K is transmitted to the driven shaft I! by engagement of said member with abutment member Ha fixed to shaft I! or by engagement with the roller 24, depending upon the direction in which said slide member K is moved, to move said shaft correspondingly. The roller 24 is thus caused to engage the friction disc at a greater or less distance from the center thereof to vary the speed of rotation of said disc, and consequently, of said main spindle H. The rotational speed of said spindle H is also controlled by selecting the portions of the step pulleys l4 and I6 over which the belt I5 is trained, as will be apparent.

Also fixed to drive shaft 1 is a pulley 35. Over this pulley and a larger pulley 35 is trained belt 31, the pulley 36 being fixed to a driven shaft 38. A step-pulley 39 is fixed to this latter shaft and trained thereover and also over a step-pulley 40, fixed to a driven shaft 4| is a belt 42. The shaft 4| is journaled in bearing cross-members 43 and 44 secured to the table or platform B. Pulley 49 is fixed to shaft 4| by a key 45 slidable in a keyway 46. Thus shaft 4| is movable through the bearings 43 and 44 in the same manner that shaft H is movable through its respective supporting bearings.

Shaft 4| extends through passages 41 and 48 of a slide member L and has secured to one end the roller 49 in driving engagement with a friction disc 50 secured to the eccentric shaft G. The slide member L is slidable from left to right, referring to Figure 4, in a guide-way 5| secured to the underside of the table B. Said slide member ,L has an internally threaded passage 52 through which extends the threaded portion 53 of a screw shaft 54 journaled in abearing 55 secured to upright member |3 of the frame A. Said shaft 54 is maintained against horizontal movement with respect to bearing 55 by a collar 55 fixed to the shaft and which engages said bear- Driven shaft 4| is movable leftwardly or rightwardly, referring to Figure 4, upon operation of the hand wheel 51 fixed to screw shaft 54, to cause engagement of roller 49 closer to or farther away from the center of disc 50, by engage ment of slide member L with abutment member 58 on shaft 4|, or roller 49, in the same manner as that described in reference to the movement of shaft IT. The speed of rotation of eccentric shaft G is thus controlled as a consequence thereof, as well as by adjustment of belt 42 upon the step- pulleys 39 and 40.

Now referring more particularly to Figures 1 to 3 it will be seen that there is supported at the top of eccentric shaft G an eccentric disc or plate M fixed thereto as by the set-screw 59. Formed on the upper side thereof is a guide-way 60 in which is slidably mounted the slide member 5| which is adapted to be fixed at any desired adjustment in the length of the guide-way by one or more of the set screws 62a, 62b, or 620. A pivot bolt 63 extends through the slidable member 6| and one end of a pitman 64, the other end of the latter being pivotally secured to a slidable plate 65 as by a pivot bolt 66 extending therethrough. The plate 65 is slidable from left to right, referring to Figures 1 and 3, in the grooved ways or channels 61 and 68 of the carrier member or bracket C, the latter being suitably secured to the upper side of the table B as by bolts or otherwise.

Fastened to the slidable plate 65 is a U-shaped bracket N between the upstanding portions 69 and 10 of which one end of the reciprocating arm D is adjustably secured as by a pin extending through a hole in said arm and through one of the pairs of oppositely disposed holes 12a, 12b or 20 in the upstanding portions 69 and 10 of the U-shaped bracket N. An adjusting screw 13 has a threaded portion 13a extending vertically through the arm D at a point between the ends thereof and engages the plate 65 to support the said arm at such point.

Also extending vertically through said arm D is a carrier pin 14 formed with a lower rounded or ball end 14a which is received in a ball socket of the abrasive block E. The pin 14 may be fixed permanently respecting the arm D or adjustably received in one of the openings 15a, 15b, 15c, 15d,

or c, its vertical position respecting said arm grinding operation by contact of said block with the lens to be ground.

Arm D is reciprocated through rotation of cocentric plate "M to which is pivotally connected the pitman 64 as above described, said pitman being free to move longitudinally and transversely in the under-cut portion 11'of the carrier C beneath the plate 65. The length of stroke'of arm D is regulated by adjusting the position of the slidable member El radially respecting the eccentric plate M, by'the means above described.

The lens block or carrier I has formed therebeneath a hub 18 which receives the upper end 79 of the main spindle H, said end 19 being splined to said hub, To the carrier I is suitably secured a lens 89 to be ground.

r 1 Operation The block of glass 80' which is to be ground into a lens having been suitably secured to the carrier I, ordinarily by cementing the same thereto, and an abrasive block E of the desired curvature having been. secured to the arm D, the proper tension of the block E upon the glass 80v is adjusted by securing the arm D to thebracket N in the desired vertical position and regulating the adjusting screw 13 with reference to the plate 65. The length of stroke of the arm D is adjusted by releasing the set screws 52a, 62b, and and moving slide member 61 radially inward or outward with respect to the center of the eccentric M.

Next the belts l5 and 42 are trained over the desired steps of the pulleys I4 and I6, and 39 and 40, respectively. The hand wheels 34 and 5'! are then operated to position the rollers 24 and 49, respectively, at the proper distance" from the center of their friction discs 25 and 50. This manipulation will regulate the speed of rotation of the main spindle H and eccentric shaft G respectively.

Now the motor F is started into operation rotating motor shaft 3 and shaft 1 through'belt' 5 trained over pulleys 4 and 6. Shaft [-1 will be consequently rotated through belt 15 trained over step-pulley I4 and 16. Main spindle H will be rotated by engagement of roller 24, fixed to shaft IT, with friction disc 25. Shaft 38 will be rotated by belt 31 trained over pulleys 35 and 36, and shaft 4| will be rotated through belt 42 trained over step-pulleys 39and 40. The eccentric shaft G will thus be rotated by engagement of roller 49, fixed to shaft 4|, with friction disc 50. Rotation of the eccentric plate M, fixed to shaft G will reciprocate the pitman 54, and consequently plate to which it is pivotally attached, bracket N secured to said plate, and arm D, attached to said bracket. This will cause abrasive block E to move across the surface of the glass 86 to grind the same. I

The tension with which the abrasive block E is held against the glass will be adjusted by turning the adjusting screw 13 to move the arm D closer to or farther away from the plate 65. As the grinding operation proceeds the ground glass dust and abrasive dust will be caught in the pan or tub 8| supported on the table B and surrounding the portion of the main spindle H protruding above the top of said table.

During the grinding operation hand wheels 34 and 51 may be actuated to vary the rotational speeds of the main spindle H and the eccentric shaft G, respectively, the latter affecting the speed of reciprocation of the arm D.

From the above it will be seen my invention provides an automatic lens grinding machine suitable for the performance of many sorts of lens grinding operations as a result of the many adjustments of the various instrumentalities provided,

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a device of the class described, in combination, a frame, a rotatable member, a re- Jail ciprocable member, one of said members carrying an abrasive material, the other of said memfor reciprocating saidcarriage respecting said first member in a straightline path, and means for vertically adjusting said arm to different fixed positions relative to said carriage while maintaining said arm in a horizontal position.

2. In a device of the class describednin combination, a frame, a rotatable member, a reciprocable member, one of said members carrying an abrasive material, the other of said members being adapted to carry a glass blank to be ground, means for rotating the first member, a carriage slidable in said frame, an arm pivotally secured to said carriage and supporting the second member proximate the first member, means associated with said carriage for reciprocating the same in a straight line path, means for vertically adjusting said arm to different fixed positions respecting said carriage, and means for vertically adjusting said second member relative to said arm.

3. In a device' of the class described, in combination, a frame, a rotatable member, a reciprocable member, one of said members carrying an abrasive material, theother of said members being adapted to carry a glass blank to be ground, means for rotating the first member, a carriage slidable in said frame, an armpivotally secured to said carriage and supporting the second member proximate the first member, means associated with said carriage for reciprocating the same in a straight line path, means forvertically adjusting said arm to different fixed positions respecting said carriage, means for vertically adjusting said second memberv relative to said arm, and means for adjusting the angle of said arm relative to said carriage.

4. In a device of the class described, in combination, a'.frame, a rotatable member, a reciproc'able member, one of said members carrying an abrasive material and the other of said members being adapted to carry a glass blank to be ground, means for rotating the first member, a carriage slidable in said frame and supporting the second member proximate the first,

and means for reciprocably sliding said carriage in said frame respecting said first member, driving means common to both'the aforesaid means and including instrumentalities interrelating the same for simultaneously varying the relative speeds of one to the other, and separate means .associated with each of said first and second means for independently varying the speed of each.

5. In a device of the class described, in combination, a frame, a rotatable member, a spindle associated therewith, a reciprocable member, one

of said members carrying an abrasive material and the other of said members being adapted to carry a glass blank to be ground, means for rotating the first member, a carriage slidable in said frame and supporting the second member proximate the first, means for reciprocably sliding said carriage in said frame respecting the first member, driving means common to both the aforesaid means and comprising a pair of rotatable spindles each of which is associated with one of said means, a friction member fixed to each of said spindles, a plurality of shafts slidable in said frame, each shaft having means engageable with one of said friction members, said driving means comprising instrumentalities for varying the rotative speeds of said shafts relative to each other, and means associated with said shafts for axially shifting the same radially respecting said friction members to vary the rotational speed of 'either' of said spindles independently of the other.

6. In a device of the class described, in combination, a frame, a rotatable member, a reciprocable member, one of said members carrying an abrasive material and the other of said members being adapted to carry a glass blank to be ground, means for rotating the first member, a carriage slidable in said frame and supporting the second member proximate the first, means for reciprocably sliding said carriage in said frame respecting the first member, driving means common to both the aforesaid means and comprising a pair oi'rotatable spindles each 01 which is associated with one of said means, ec-

centric means associated with one of said spin-v dles and said carriage for reciprocating the latter, means associated with each of said spindies for varying the rotative speed thereof independently of the rotative speed of the other, said driving means including instrumentalities interrelating said spindles for simultaneously l0 varying the relative rotative speed of each to the other.

ROBERT E. FOSDICK.

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