US3330075A - Sphere polisher - Google Patents

Description

July 11, 1967 J. M. SUDDARTH ETAL 3,

SPHERE POLISHER 2 Sheets-Sheet l Filed July 1, 1964 AIR , PUMP INVENTOHS DOLPH L. GRAY PRESSURE REGULATOR Q JACK M; 5000mm ar m vfr y 1, 1957 J. M. SUDDARTH ETAL 3,330,075v SPHERE POLISHER Filed July 1, 1964 2 Sheets-Sheet 2 'l/vv/v r ofis JACK M. SUDDfiRTI-I FIG 4 DOLPH L. 6R4) United States Patent 3,330,075 SPHERE POLISHER Jack M. Suddarth, Fort Gibson, and Dolph L. Gray, Muskogee, Okla., assignors to Cohurn Manufacturing Company, Inc., Muskogee, Okla, a corporation of Oklahoma Filed July 1, 1964, Ser. No. 379,499 Claims. (Cl. 51-124) This invention relates generally to a sphere polisher and more specifically relates to improved sphere polishers for the polishing and fining of opthalmic lens. The improvement disclosed herein permits accurate stroke control adjustment and maintains a constant pressure between lap and workpiece throughout a polishing stroke.

Polishers of the type described hereinafter are comprised basically of a pre-selected, rotating, spherical polishing lap with means for maintaining a lens in engagement with the rotating lap as the lens follows an oscillating stroke from a point near the periphery of the lap past the crown or axis of rotation of the lap. It is an objective of the invention to provide mean for accurately setting and adjusting the location and extent of this stroke while the machine is idle or operating. The means include both a coarse and fine manually operated apparatus.

Another important objective of the invention is in the provision of pressure regulated pneumatic means for maintaining a constant pressure between lap and lens as the lens travels its oscillating stroke.

A still further important objective of the invention is in the provision of linkage structure readily enabling the line of force of the pressure means to be applied perpendicularly to the lap at the midpoint of the lens stroke.

Another objective of this invention is in the provision of mechanisms and controls for accurately maintaining pressure between the lens and the lap of suflicient magnitude to cause a cold flow finishing of the glass heretofore not obtained'in the prior art because of excessive breakage.

These and other important objectives and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof and where- FIGURE 1 is a perspective view with portions broken away;

FIGURE 2 i a diagrammatic-schematic front view of the apparatus shown in FIGURE 1;

FIGURES 3a, 3b, 3c and 3d are diagrammatic-exploded views of the adjusting linkage; and

FIGURE 4 is a plan diagrammatic view of the linkage shown in FIGURES 3a-3c.

Referring now to the drawings, wherein like elements are indicated by like numerals in the several views, the numeral indicates a base housing for this invention. At its first or outer end, the housing support a polishing bowl 12 and at its inner end supports a control housing 14. The housing includes a motor for conventionally driving the polishing tool or lap 16 via a drive shaft 18. Standard means for maintaining a supply of cerium oxide polishing slurry to the bowl is provided but forms no part of this invention.

The lap i replaceably mounted to the drive shaft 18 and has a surface curve the same as the prescription curve to be formed on the surface of a lens 20. As is conventional in the polishing art, a block 22 is secured to one side of the lens. The rear of the block is formed with a central cone-shaped recess 21 for accepting a drive pin 24 which is tapered at 23. A will be understood more .fully hereinafter, pin 24 oscillates the lens along a path P (FIG. 2) and maintains a pressure between the lens and lap as the polishing tool is rotated. The path extends beyond the lap center line 2 to 4 mm. to maintain constant and to eliminate aberrated lenses.

As previously stated, a principal feature of this invention is in the provision of pneumatic means for maintainmg a constant pressure between the lap and lens. To -accomplish this, an air pressure regulator 26 within housing 14 is variable upon a turning of an operator-adjustment knob 28 of the control panel. A pressure sensing control depicts the selected pressure on a dial 30 also on the control panel. A control knob 32 on the face of housing 14 is for selecting the speed for the drive motor of lap 16 via conventional controls.

The pin 24 is supported on the housing at one end of a support linkage system 25. The linkage will be described after a preliminary disclosure of the apparatus for maintaining a selected pressure on the pin. The upper end of drive pin 24 forms a piston head 34 which is slidably received in a single acting pneumatic cylinder 36. The pressure from the regulator 26 is communicated to the expansion chamber 40 of the cylinder via a conduit 42. Suitable pneumatic seals, feltings, and the like for selected Working pressures of from Zero to approximately 100 pounds are provided between the piston and cylinder.

The vertical height of cylinder 36 i adjustable in a split block assembly 44. The assembly 44 permits the cylinder 36 to be lowered into engagement by handle 46 but is equipped with a one-way clutch mechanism to prevent cylinder movement from forces exerted via pin 23. The assembly 44 can be better understood by reference to our co-pending application entitled Cylinder Polisher filed on the filing date of this application. The outer or inner end of block 44 is terminated by a shaft section 48 which is rotatably received in a chuck 50. The chuck 50 forms the top of a spindle 56 rotatably mounted with respect to housing 14 and receivable in a horizontal split clamping ring 58. The spindle provides a means to swing the pin 24 to a selected position along path P with respect to lap 16. After the desired position has been selected, the ring 58 is clamped to the spindle for oscillation as a unit.

Thus far there has been described a means for moving pin 24 into the block recess 21, namely, the sliding relationship of cylinder 36 with block 44; a means for arranging pin 24 normal to the surface of the lap, namely, shaft 48 rotating Within chuck 50; and a means for selecting stroke location; namely, the rotation of spindle 56 in clamping ring 58. The means for stroking the above-mentioned parts together with the means for adjusting troke length and the means for finely adjusting stroke location will now be described.

An ear 60 is fixedly secured to the clamping ring 58 and is the connecting arm between the spindle and the stroke power supply. Spaced from ear 60 and extending vertically upwardly from housing 14 (behind spindle 56 in FIGURE 1) is a rotating output shaft 62. Shaft 62 is driven from a conventional electrical motor Within housing 14. A linkage broadly indicated by the numeral 74 transforms the rotating output of shaft 62 to an oscillating input in spindle 56.

Extending from the upper surface of shaft 62 is an offset pin 64 which rotates about the center axis of shaft 62 a first distance. A friction pad 65 is slipped over the pin 64 and engages shaft 62. A rod member 66 having a pin-receiving slot 67 displaced from its central axis is slidable over the pin 64 and the lower surface thereof engages the upper side of friction pad 66. A linkage arm 68 is formed with an opening 70 for rotatably receiving the member 66. With this arrangement, it can be seen that if member 66 assumes the position shown in FIG- URE 3a, the length of the oscillating stroke imparted to arm 68 is at a maximum because the total eccentricity is the sum of the displacements of pin 64 and hole 67 wear from their shaft center axis. With member 66 rotated from the FIGURE 34: position to that shown in FIG- URE 3b, the displacement of the slot 67 oifsets the displacement of pin 64 and stroke length is decreased to a minimum. For operator convenience, a knob 71 is fixedly secured to the periphery of member 66 so that the rotation of member 66 with respect to shaft 62 is facilitated. It has been found desirable to spring urge member 66 toward shaft 62 so that proper compression of the friction pad results. Proper compression is obtained by a slight bias pressure of any known means. For instance, member 66 can beflanged or collared at 73 and a coil spring 75 inserted between the flange and member 74. With the proper compression, the member 66 will maintain a fixed position with respect to shaft 62 unless forceably rotated by the operator via knob 70. This rotation can be made, of course, while the shaft 62 is rotating.

As previously mentioned, the location of drive pin 24 with respect to the finishing block is selected by rotating standard 56 prior to clamping. Many times, however, it

7 is desirable and necessary. to adjust stroke location after the finishing operation has started. The linkage arm 68 at its other end is provided with an opening 72 which rotatably engages a cylindrical member 74 having an axially oifset opening 76. The opening 76 receives a pin 78 which extends vertically upwardly from the ear 6%. An extension handle 80 is fixedly secured to the upper end of member 74 so that the operator can rotate the member with respect to the ear 60. A friction pad 82 is situated between the member 74 and the upper surface of ear 60 to maintain their angular relationship unless forceably moved by the operator. Again, it has been found desirable to bias the member 74 toward the rear for proper compression. One convenient way is to flange or collar the lower end of 74 as at 77 and dispose a spring 79 between the flange and member 74.

It is evident that a rotation of member 66 with respect to linkage arms 68 varies the stroke length and that a rotation of member 74 with respect to linkage member 68 rotates the posit-ion or location of the final stroke imparted to pin 24. This is true because at the time of making these final adjustments there is a rigid linkage between ear 60 and the pin 24.

In operation, an operator selects a particular polishing lap with the proper curve and, when desired, firmly attaches a polishing pad, as known to the art. The lap is secured to drive shaft 18 making sure that it is sung and does not wobble. The blocked lens is placed on the lap and pin 24 is placed in engagement with recess 22. In order to place pin 24 normal to the surface of the lap at approximately mid-stroke position, the assembly is rotated in clamping block 44 and spindle 56 is rotated accordingly. The clamping ring 58 is then tightened.

With the members 66 and 74 disposed as in FIGURE 3a the stroke length is at a maximum. When member 66 is rotated by handle 71 to the position of FIGURE 3b, the stroke center remains the same but stroke length is reduced as seen by the dotted lines of FIGURE 3a. With member 66 disposed as in FIGURE 3!; and member 74 rotated to its FIGURE 3c position, the location of the short stroke length of FIGURE 3b is changed as disclosed by the other pair of dotted lines in FIGURE 1.

A selected pressure is set and the pressure within chamber 40 maintains the lens against the lap via pin 24. After observing the stroke for several seconds, the operator adjusts the stroke length by rotating member 66 and makes a fine adjustment of stroke location by rotating the member 74.

There has been described an extremely versatile unit for the automatic fining and polishing of ophthalmic lenses. The use of an air pressure biasing means insures uniformity of pressure from the periphery of the lap to that area of the stroke over the crown. This, coupled with the means for finely adjusting both stroke length and location permits the utilizing of pressures heretofore not used in this art because of breakage.

In a general manner, while there has been disclosed an effective and eflicient embodiment of the invention, it should be well understood that the invention is not lim ited to such an embodiment, as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims. a

We claim:

1. A linkage arrangement for supporting an oscillating drive member comprising an output shaft rotatablev about its center axis, a pin extending upwardly from said shaft and oifset from said center axis, a first rod having a circular cross-section and a slot offset from the rod axis receiving said pin, a friction element between and engaging said shaft and said rod normally causing said rod and said shaft to rotate as a unit, an arm having a journal opening at one end rotatably receiving said rod and receiving an oscillating motion as said shaft and rod rotate dependent in length upon the distance relationship between the center axis of said shaft and center axis of said journal opening, said arm having a second journal opening at its other end, a second rod member having a V circular cross-section rotatably received in said second opening and having a pin-receiving opening offset from the center axis of said second rod, a standard rotatable about an axis parallel to the vertical axis of said drive shaft and supporting said drive member, an ear extending radially outwardly from said standard, a pin extending upwardly from said ear into said pin-receiving opening, means to secure said rod to said ear at selected radial positions of the center axis of said rod with respectto said pin, whereby the length of said oscillations of said drive member can be varied by selecting the amount of affect between the axis of said output shaft and the center axis of said pin and the location of said oscillations can be varied by adjusting the radial position of said second rod with respect to said ear.

2. The linkage recited in claim 1 wherein said means comprises a second friction pad between ear and said second rod. 7

3. The linkage of claim 2 wherein first and second handles are respectively secured to said first and second rods for manually rotating said rods in opposition to. said first and second friction pads.

4. The structure for holding a lens having a block secured thereto in engagement with a rotating lap comprising: a fluid cylinder, a drive pin having a first end in driving engagement with said block and a second end forming a sliding piston with said cylinder, said cylinder and said second end forming an expansion chamber, a source of pressurized fluid, a conduit means communicating said source with said chamber, means in said conduit to maintain the pressure in said chamber constant,

,a linkage arrangement for oscillating said lens and block over a path along said lap surface, said linkage arrangement comprising an output shaft rotatable about its center axis, a pin extending upwardly from said shaft and offset from said center axis, a first rod having a circular cross-section and a slot offset from the rod axis receiving said pin, a friction element between and engaging said shaft and said rod normally causing said rod and said shaft to rotate as a unit, an armhaving a journal openporting said drive member, an ear extending radially outwardly from said standard, a pin extending upwardly from said ear into said pin-receiving opening, means to secure said rod to said ear at selected radial positions of the center axis of said rod with respect to said pin, whereby the length of said oscillations of said drive member can be varied by selecting the amount of afiect between the axis of said output shaft and the center axis of said pin and the location of said oscillations can be varied by adjusting the radial position of said second rod with respect to said ear.

5. The structure for holding a lens having a block secured thereto in engagement with a rotating lap comprising: an air cylinder, a drive pin having a first end in driving engagement with said block and a second end forming a sliding piston with said cylinder, said cylinder and said second end forming an expansion chamber, a source of air pressure, a passageway communicating said source with said chamber, an adjustable pressure regulator in said passageway controlling the pressure in said chamber, a linkage arrangement for oscillating said lens and block over a portion of the lap surface, said linkage arrangement comprising as output shaft rotatable about its center axis, a pin extending upwardly from said shaft and ofi'set from said center axis, a first rod having a circular cross-section and a slot oflset from the rod axis receiving said pin, a friction element between and engaging said shaft and said rod normally causing said rod and said shaft to rotate as a unit, an arm having a journal opening at one end rotatably receiving said rod and receiving an oscillating motion as said shaft and rod rotate dependent in length upon the distance relationship between the center axis of said shaft and center axis of said journal opening, said arm having a second journal opening at its other end, a second rod member having a circular crosssection rotatably received in said second opening and having a pin-receiving opening offset from the center axis of said second rod, a standard rotatable about an axis parallel to the vertical axis of said drive shaft and supporting said drive member, an ear extending radially outwardly from said standard, a pin extending upwardly from said ear into said pin-receiving opening, means to secure said rod to said ear at selected radial positions of the center axis of said rod with respect to said pin, whereby the length of said oscillations of said drive member can be varied by selecting the amount of affect between the axis of said output shaft and the center axis of said pin and the location of said oscillations can be varied by adjusting the radial position of said second rod with respect to said ear.

References Cited UNITED STATES PATENTS 873,649 12/1907 Allen 7460O X 1,527,045 2/1925 Howland 51124 1,659,2'77 2/1928 Maynard 51124 2,225,826 12/ 1940 Duifens 51- 124 2,880,555 4/ 1959 Brueckner 51-l24 2,977,724 4/ 1961 Kennedy 51-124 FOREIGN PATENTS 569,807 2/ 1933 Germany.

HAROLD D. WHITEHEAD, Primary Examiner.

Claims (1)

1. 4. THE STRUCTURE FOR HOLDING A LENS HAVING A BLOCK SECURED THERETO IN ENGAGEMENT WITH A ROTATING LAP COMPRISING: A FLUID CYLINDER, A DRIVE PIN HAVING A FIRST END IN DRIVING ENGAGEMENT WITH SAID BLOCK AND A SECOND END FORMING A SLIDING PISTON WITH SAID CYLINDER, SAID CYLINDER AND SAID SECOND END FORMING AN EXPANSION CHAMBER, A SOURCE OF PRESSURIZED FLUID, A CONDUIT MEANS COMMUNICATING SAID SOURCE WITH SAID CHAMBER, MEANS IN SAID CONDUIT TO MAINTAIN THE PRESSURE IN SAID CHAMBER CONSTANT, A LINKAGE ARRANGEMENT FOR OSCILLATING SAID LENS AND BLOCK OVER A PATH ALONG SAID LAP SURFACE, SAID LINKAGE ARRANGEMENT COMPRISING AN OUTPUT SHAFT ROTATABLE ABOUT ITS CENTER AXIS, A PIN EXTENDING UPWARDLY FROM SAID SHAFT AND OFFSET FROM SAID CENTER AXIS, A FIRST ROD HAVING A CIRCULAR CROSS-SECTION AND A SLOT OFFSET FROM THE ROD AXIS RECEIVING SAID PIN, A FRICTION ELEMENT BETWEEN AND ENGAGING SAID SHAFT AND SAID ROD NORMALLY CAUSING SAID ROD AND SAID SHAFT TO ROTATE AS A UNIT, AN ARM HAVING A JOURNAL OPENING AT ONE END ROTATABLY RECEIVING SAID ROD AND RECEIVING AN OSCILLATING MOTION AS SAID SHAFT AND ROD ROTATE DEPENDENT IN LENGTH UPON THE DISTANCE RELATIONSHIP BETWEEN THE CENTER AXIS OF SAID SHAFT AND CENTER AXIS OF SAID JOURNAL

Images