US2309936A - Lens grinding and polishing machine - Google Patents

Description

Feb. 2, 1943. R c, VI

LENS GRINDING AND POLISHING MACHINE Filed Dec. 23, 1940 2 Sheets-Sheet 1 INVENTOR fiyMa/vo C 04140 MUM ATTO RN EY Feb. 2, 1943. R. c. DAVID LENS GRINDING AND POLISHING MACHINE Q Filed Dec. 23, 1940 2 Sheets-Sheet 2 INVENTOR 0 C w m y M ATTORNEY Patented Feb. 2, 1943 2,309,936 LENS GRINDING AND POLISHING MACHINE Raymond C. David, Leominster, Mass, assignor to Fosgood Corporation, Leominster, Mass., a corporation of Massachusetts Application December 23, 1940,

Serial No. 371,293

7 Claims. (01. s1 111) This invention relates to a machine for grinding and polishing lenses having two curved surfaces, such as are commonly known as coquille lenses. 1

The primary object of the invention is to provide a machine for grinding or polishing .both curved surfacesof a plurality of lenses simultaneously.

'Another object is to provide a machine for abrading both curved surfaces of the lenses evenly throughout their entire area.

Another object is' to provide a machine for grinding and polishing a plurality of coquille lenses to a given uniform thickness in all parts.

A further object is to provide a machine having two opposed, oppositely rotating curved abrading tools or laps that act simultaneously on both curved panying drawings, in which:

Figure 1 is a view in elevation of the lapping machine. showing the laps separated;

Fig. 2 is a view in elevation, partly in section,

showing the laps in abrading position; and

Fig. 3 is a fragmentary top view of the lensholder or spider.

The machine has two opposed curved rotary tools or laps l0 and II between which a correspondingly curved spider or lens-holder I2 is interposed. The upper rotary lap I0 is mounted to move vertically, and it has a concave abrading surface I3. mountedandhas a convex abradirig surface M of concentric curvature to that of the surface! 3 of the upper lap.

The upper lap foot of a hollow I0 is carried on and is fixed to the rotary shaft [5, which shaft turns The lower-rotary la'pllfis stationarily in suitable bearings H3 in, and is supported by, the frame member 11. The frame member I! is bodily movable vertically on the frame-stanchion The shaft may be driven by a pulley l9, keyed thereto at 20, through a belt 2| or the like from The latter pulley is vertically mov- R. P. M.

The knob 31 seats in a socket 39 disposed ec centrically in the enlarged foot of a vertical rod 40, by rotation of which rod the spider movement is actuated. The rod passes freely through the axial bore 4! of the rotary shaft ported at its parison of Figs. 1 and 2 of the drawings.

The rod 40 is independently rotated. but in the same direction as the' lap H), by a gear 43. through the reduction gears 48, from a driving fixed-to the upper 'end of the rotary shaft 15. The ratio of the gears is such that the rod will rotate at a considerably slower speed than the shaft, and consequently than the lap Ill. The ratio is preferably such that when the lap rotates at about 110 R. P. M., the rod 40 will rotate at about 35 R. P. M., although these velocities, as well as the relative velocities, may be varied. The gear-train is carried and mounted on the vertically movable frame member I! to move up and down with said frame member.

The fork 38 of the spider l2 engages a fixed upright pin 46 by which the motion of the spider is controlled. Because of its eccentric drive, as governed bythe pin and compound motion that is the resultant of its impulses to rotate eccentrically in relation to the axis of the laps, to oscillate relatively to the pin, and to rock back and forth on the curved surface of the lower lap. This compound motion of the spider, coupled with the fact that the lenses themselves turn in the openings in the spider, by reason of the differential velocities of the two lay-r, produces a smooth, uniform and even abfork, the spider has a rasive action, simultaneously and in parallelism,

on both curved surfaces of each of the lenses throughout their entire area. The frame-part 41, to which the pin 46 is fixed, ispreferably in the form of an apron to prevent spattering of the abrasive operations of grinding and polishing the lenses.

Any suitable means may be provided for raising or lowering the upper lap ID as required. A mechanism for this purpose is shown in the drawings consisting of a toggle 48 composed of two links 49 and 50 pivoted together at 5|. The upper link 49 is pivoted at 52 to the vertically movable frame member l1, while the lower link 50 is pivoted at 53 to a stationary part of the frame. A handle 54 operates the toggle, and a stop 55, or equivalent means, may be provided for limiting the movement of the toggle and to hold the upper lap iii in its raised position.

To facilitate the up and down movement of the movable member II on the stanchion I8, the member l1 may be provided with a smooth flat face 56 against which a roller 51 may bear, and

the roller may be provided with an adjustable screw 58, or the like, for adjusting its pressure.

In operation of the machine, the lap I0 is raised to give access to the spider l2, and the coquille lenses 36 are placed in the openings 35, after which the lap is lowered to its operative position, shown in Fig. 2. The laps are then caused to rotate and the spider is caused to move the lenses about in between the rotating laps, but at a slower rate of motion. After the grinding and polishing operations are finished, or whenever desired, the upper lap may be raised, by manipulation of the toggle 48, to permit of in spection of the lenses or their removal from the spider.

While I have shown and described a preferred embodiment of, the invention, it is to be understood that modifications may be made within the substance during the aaoefeae ing a plurality of lenses disposed between the laps, and means for rocking and oscillating the spider relatively to the laps including an eccentric connection of the spider to the rod.

2. In a machine of the character described, a pair of opposed rotary curved laps", a spider for holding a plurality of lenses between said laps, and means for moving the spider with a compound motion which is the resultant of rotary, oscillatory and rocking movements imparted to the spider.

3. In a machine of the-character described, a pair of opposed rotary curved laps, a curved spider for holding a plurality of lenses between said laps, means for rotating said spider eccentrically to the axis of the laps, a fork extending downwardly and outwardly from an edge of the spider, and a fixed pin upon which the fork rides to cause the spider; to oscillate and to rock relatively to the laps.

4. In a machine of the character described, a pair of rotary laps in axial alignment, said laps having opposed faces of common curvature, one of which is concave and the other convex, means for rotating both laps in opposite directions with a differential speed, a work-holder disposed between the laps and shaped to conform to the opposed faces thereof, said work-holder being adapted to hold a plurality of lenses loosely to permit of turning movement of the lenses in the holder during rotation of the laps, and means for rotating the work-holder eccentrically with respect to the axis of the laps and imparting a compound oscillatory and rocking movement thereto.

5. In a machine of the character described, a pair of rotary laps in axial alignment, said laps having opposed faces of common curvature, one of which is concave and the other convex, means for rotating both laps with a differential speed, a work-holder disposed between the laps and shaped to conform to the opposed faces thereof,

said work-holder being adapted to hold a pluscope of the invention as set forth in the claims.

rality of lenses loosely to permit of turning movement of the lenses in the holder during rotation of the laps, and means for rotating the workholder eccentrically with respect to the axis of the laps and imparting a compound oscillatory and rocking movement thereto.

6. In a machine of the character described, a pair of rotary laps in axial alignment, said laps having opposed faces of common curvature, one of which is concave and the other convex, means for rotating both lapsga work-holder disposed between the laps and shaped to conform to the opposed faces thereof, said work-holder being adapted to hold a plurality of lenses loosely to permit of turning movement of the lenses in the holder during rotation of the laps, and means for rotating the work-holder eccentrically with respect to the axis of the laps and imparting a compound oscillatory and rocking movement thereto.

'7. In a machine of the character described, a pair of opposed rotatable laps, a work-holder for loosely holding a plurality of lenses therebetween, an independently rotatable shaft extending axially through one of said laps, said work-holder being connected eccentrically to said shaft, and means for guidingtlre movement of the workholder to impart -a compound'oscillating and rocking sliding movement thereto between the laps.

RAYMOND C. DAVID.

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