US2754638A - Lens surfacing machine - Google Patents

Description

July 17, 1956 DUFFENS ET AL 2,754,638

LENS SURFACING MACHINE Filed Dec. 20, 1954 3 SheetsSheet l Mae/ 3 I w- El 25 INVENTORS.

July 17, 1956 R DUFFENS ET AL 2,754,638

LENS SURFACING MACHINE Filed D60. 20, 1954 3 Sheets-Sheet 2 l 111 8 INVENTORS.

E,Du. ans 4 By Duuens July 17, 1956 R E- DUFFENS ET AL 2,754,638

LENS SURFACING MACHINE Filed Dec. 20, 1954 3 Sheets-Sheet 3 I M 1 11 W/A/ r INVENTORS R E b fiansan BY 3115 United States Patent 2,754,638 LENS 'SURFACING MACHINE Robert E. Dulfens and Roy A. Duflen's, Topeka, Kans.

ApplicationDecember 20, 1954, SerialNo. 476,414

3 fllaims. ((31.51-460) This invention. relates .to cylindrical lens surfacing machines and-has forits .chiefobject to produce a multiple 'head machine whereby extensive use is made of selflubricated self-aligning hearings to permit the random or non-repetitive traverse of the lensover the lap so that a fixed grinding or lapping pattern will .be avoided.

One of the objects of .the .invention .is to provide a machine of this character in which .all-of the bearings are sealed against the entrance of grinding compound which sometimes escapes into the oil bath of present machines. Such an event causes early .failure of the bearings.

Another object of the invention to provide novel means .for tensioning the lens. against the lap which is so mounted that accidental detachment of the parts is avoided.

With the general objects named in view and others as will hereinafter appear, the invention consists in certain new and useful features of construction and organization of parts as hereinafter .describfedand claimed; and in order that it may .befully understood, "reference is to be had to the accompanying drawings, in which:

Figure 1 is a front .view of a machine embodying the invention, partially'brdken away 'toillustrate parts otherwise hidden.

Figure 2 is a section taken through the rear of the machine as viewed toward the front, said section being on the line II--II of Figure 3.

Figure 3 is a horizontal section through the machine just below its top.

Figure 4 is a section on the line IV--IV of Figure 3.

Figure 5 is an enlarged side view of the lens head tensioning mechanism with the cover plate removed.

Fig. 6 is a section on the line of Figure 5.

Figure 7 is a section on the line VIIVII of Figure 5.

In the said drawings, where like reference characters identify corresponding parts in all of the figures, 1 is a generally rectangular base formed with an upstanding rectangular section 2 bridging said base at its front end. The front end of the frame section 2 is recessed for removably receiving a liquid rouge or grinding or polishing compound receiving basin 3 provided with a liquid circulating pump 4 connected by tubes 5 to feed liquid to the faces of the laps 6 removably secured within the basin as shown.

Mounted on a cross frame member 7 is an electric motor 8 which drives a belt 9 to rotate a wheel 10 which frictionally drives the pulley 11 for operating the pump 4. The belt 9 encircles a spring advanced idler 12 which maintains the belt tight but yields to permit change in the center of the wheel shaft 13 as later describer. Shaft 13 is journaled in the upper edge of a plate 14 mounted to rock on bearings 15 carried by the bottom of the machine 1.

Behind the wheel 10, the shaft 13 carries an eccentric 16 which is connected by rod 17 to one end of a lever arm 18 keyed to a shaft 19 journaled in an ear 20 carried by the frame 2 of the machine. Keyed to the other end of the shaft 19 is a slotted rock arm. 21. The rock arm .heads 22 as will hereinafter appear.

In the machine as illustrated there are four lens heads 22, .cach pair of heads at opposite sides of the center line of the machine oscillating in unison. These heads 22 are rockingly carried by the .ends of rod23 secured in castings 24 to oscillate vertically in ears 25 carried by auxiliary frame bars 26 so that the lens heads 22 in their movement over the lap follow thecontour thereof. Each of the auxiliary frame members 26 is pivoted at 27 to the upper ends ofpairs of rock arms 28 which in turn are pivoted at 29 .to blocks 30 constituting a subframe member and being rockingly related. to shaft 31 carried by ears 32 projecting upwardly .from the cross frame member 7.

In order .to impart transverse. rocking movement to .auxiliaryframes 26 around the centers of shafts 27 and 29, the rock arm 21 is connected respectively at its opposite ends by links 33 and 34 equipped with self-aligning bearings at their ends. The length of stroke can be adjusted in the slots of the rock arm 21.

In order to impart longitudinal rocking movement to the lens carrying heads 22 at right angles to transverse movement, links 35 are connected .to auxiliary frames 26 by self-aligning bearings, the opposite ends of said links being also equipped with self-aligning bearings having adjustable eccentric movement inslotteddisks 36 keyed to the ends of shaft 37. By shifting the .ends of the links in the slotted disks, the back. and forth stroke can be adjusted as desired. The shaft 37 carries a pulley 38 driven by a belt 39 encircling pulley 40 on a short shaft 41, said shafts 37 and 41 being journaled in bearings carried by the bridge frame 42.

Shaft 41 has a pulley 43 which is encircled by a belt 44 driven by an electric motor 45. The belt 44 also drives pulley 46 of a speed reducer 47. The slow speed shaft 48 of the speed reducer has a cam 49 and a crank 50. Riding on cam 49 is a follower arm 51 pivoted at one end to the frame 42, and carrying an idler 52 at its other end in contact with belt 44. As the cam rotates the idler 52 rocks and alternately increases and decreases tension on the belt 44 which automatically changes the speed of the belt 44 due to its reaction on the variable speed pulley 53 on drive motor 45.

The crank 50 may oscillate the plate 14 in any suitable way as by forming a slot 54 in the edge of the plate as illustrated in Figure 4. Rocking of plate 14 shifts the center of wheel 10 and changes the path of oscillation imparted to the lens carrying head 22.

In order to provide for variable tension or pressure of the lens carried by heads 22 against the laps 6, the castings 24 at their ends carry self-aligning bearings which are connected to the lower ends of retractile spring 55, the upper ends of said springs extending through slots 56 in the frame 2. Mounted on the frame over the slots is a housing shell 57 secured to the frame and provided with a removable cover 58.

Shell 57 is tapped to receive a bolt 59 having an Allen-head or other suitable socket 60 at one end flush with the cover 58, said bolt being locked against rotation by a nut 61. Journaled on the bolt is a locking disk 62 formed integrally with an operating handle 63, the opposite faces of said disk frictionally contacting the inner face of the shell 57. The opposite face of disk 62 frictionally contacts a second disk 64 which is integrally formed with an operating handle 65. The other face of disk 64 is in frictional contact with a hardened locking disk 66 which in turn is clamped by the locking head 66.

Disk 64 is formed with a series of through openings which loosely receive ball bearings 67 slightly greater in diameter than the thickness of disk 64 so that said balls project into tapered or wedge seats 68 formed in the face of the disk 62. Normally the clamping pressure applied by the Allen head bolt, is such that a spring 69 secured at one end to an arm 70 secured to disk 62 and at its other end to the periphery of disk 64 causes movement of the disk 64 to shift the balls up the wedge faces 68 so that lever 63 is locked against movement by the jamming of the balls between wedge faces 68 and the hardened disk 66. Movement applied to lever 65 against the tension of spring 69 will reset the balls to the center of depressions 68 and release the assembly so that disks 62 and 64 may be rotated in unison to change the tension applied to spring 55.

Disk 62 is formed with an extension arm 71 to which a self-aligning bearing 72 may be secured, said bearing having a stem 73 permanently attached to the end of spring 55. With the above arrangement it will apparent that when handles 63 and 65 are aligned, the balls 67 are centered and the device is unlocked for tensioning the spring 55 as desired. With this arrangement tension can be applied in unlimited increments rather than in stepped fashion as occurs with a pawl and ratchet or similar mechanism.

From the above description it will be apparent that we have produced a construction embodying all of the features of advantage set forth as desirable, and while we have described and illustrated the preferred arrangement, it is to be understood that we reserve the right to all changes within the spirit and scope of the appended claims.

We claim:

1. In a lens surfacing machine, a lap support, a lap carried thereby, a vertically oscillating lens-carrying head to be adjustably urged toward the lap, resilient means for urging the head in one direction, a rotatable lever for tensioning the resilient means to regulate the pressure between the lap and the head, said lever having tapering depressions, a second rotatable lever having one face adjacent the first lever, a pressure plate adjacent the opposite face of the second lever, said second lever having a series of through passages, a series of balls loosely received in the openings and projecting into the tapering depressions of the first lever, and resilient means tending to move the second lever to shift the balls in the tapering depressions to lock the first lever against movement due to the force exerted by the tensioned resilient means.

2. In a lens surfacing machine, a supporting framework, a fixed tool carried by the framework, 2. plate rockingly carried by the framework, a shaft journaled on the rocking plate, a wheel keyed to the shaft, a driven belt encircling the wheel, a fluid circulating pump frictionally driven by the wheel, a cam on the shaft, a work holder mounted to oscillate in two directions at right angles over the tool, linkage between the cam and work holder to oscillate the latter in one direction, a second driven shaft for effecting rocking of the plate, a crank rotated by the second driven shaft, and a link connecting the crank to the work holder to oscillate the holder in a direction at right angles to the first-named oscillation.

3. In a lens surfacing machine, a supporting framework, a fixed tool carried by the framework, a plate rockingly carried by the framework, a shaft journaled on the rocking plate, a wheel keyed to the shaft, a driven belt encircling the wheel, a fluid-circulating pump driven by the wheel, a cam on the shaft, a work holder mounted to oscillate in two directions at right angles over the tool, linkage between the cam and work holder to oscillate the latter in one direction, a second shaft for oscillating the work holder at right angles to that imparted by the linkage, a driven variable speed belt for rotating said second shaft, a crank actuated by the second shaft to rock said plate, a second cam on said second shaft, a rock lever actuated by the cam, and an idler on the rock lever in contact with the belt for effecting variation in belt speed.

References Cited in the file of this patent UNITED STATES PATENTS 621,181 Thompson Mar. 14, 1899 1,381,245 Simpson June 14, 1921 2,285,377 Inman June 2, 1942 2,381,449 Holman Aug. 7, 1945 FOREIGN PATENTS 804,761 Germany Apr. 30, 1951

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