Lens blocker

Sept. 23, 1969 j. _M. suddarth 3,468,366

LENS BLOCKER

Filed Feb. 20, 1967 2 Sheets-Sheet 1

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FIG. 2

INVENTOR

JACK M. SUDDARTH

ATTORNEYS

Sept. 23, 1969

J. M. SUDDARTH

LENS BLOCKER

3,468,366

Filed Feb. 20. 1967

Sheets-Sheet 2

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ATTORNEYS

3,468,366

Patented Sept. 23, 1969

United States Patent Office

3,468,366 LENS BLOCKER Jack M. Suddarth, Muskogee, Okla., assignor to Cobum Manufacturing Company, Inc., Muskogee, Okla., a corporation of Oklahoma Filed Feb. 20, 1967, Ser. No. 617,213 Int. Cl. B22d 19/00

U.S. Cl. 164—332 1 Claim

ABSTRACT OF THE DISCLOSURE

A lens blocking apparatus having a heated container for low melting temperature alloys, a chuck for holding a lens blank over a blocking chamber and pump means for delivering the fluid alloy to the chamber.

This invention relates to a lens blocker and more particularly to an apparatus for blocking ophthalmic lens with a 20 low melting point alloy.

The principal objective of the invention is to provide an apparatus which will insure a new block each time for the lens.

Another objective of the invention is to provide a com- 25 pact blocking device which will mold a small solid block of metal directly to the lens.

A further objective of the invention is to provide an apparatus which will block a lens and leave a wide margin of glass around the block free from obstruction. 30

A yet further objective of the invention is to provide a lens blocker with a light means for centering the lens.

These and other objects of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light 35 of the accompanying drawings, wherein like elements throughout the figures thereof are indicated by like numerals and wherein;

FIGURE 1 is a perspective view of the metallic blocker;

FIGURE 2 is a perspective view of the internal com- 40 ponents of the metallic blocker;

FIGURE 3 is a section view taken along line 3—3 of FIGURE 2;

FIGURE 4 is a top view of the plastic cap of this invention; and 45

FIGURE 5 is a section view taken along line 5—5 in FIGURE 3.

Referring to FIGURE 1, the metallic blocker generally has a housing framework 10 with substantially vertical side walls 12 and a horizontal lid 14 on its upper rear portion. The upper forward portion is sloped downwardly from the lid 14 to a front wall 16 thereby providing a face 18. The lid 14 is hinged at its outer end and has a handle 19 at its inner end. Located on the sloping face 18 are a self-locking pressure handle assembly 20, a metal injector lever 22, an insulator 24, and a metallic ring 26. An ejector lever 27 protrudes from the side wall 12 while a toggle switch 28 and indicator light 30 protrude from the front wall 16. The pressure asssembly 20 is used to hold the lens against the metallic ring 26 while the injector lever 22 is used to pump the metallic alloy through the insulator 24 into a blocking chamber just below the clamped lens. When the metal has cooled to solidification, the pressure assembly is released and the ejector lever 27 is rotated to free the lens and attached block.

The face 18 is removably secured to the housing 10 by means of bolts 33. Two apertures 34 and 36 are formed in the face 18 to seat the metallic ring 26 and the insulator 24 respectively.

The self-locking pressure handle assembly 20 is of the type disclosed in co-pending application Ser. No. 590,397, filed Oct. 28, 1966. A lever 21 will cause a work-engaging arm 46 to move up or down but once released will not move in response to forces applied at the free end of the aforesaid arm 46. The components of the handle assembly 20 are rotatably supported in a housing 38 which is rigidly 5 secured to the face 18. The free end of the arm 46 snugly receives a cap 50 of rubber, plastic, or other resilient material which will not scratch the lens. The lever 21 and the arm 46 are substantially perpendicular to the axis of the shaft 42. The arm 46 is long enough to centrally locate 10 the cap 50 over the metal ring 26 when in the work-engaging position.

As best seen in FIGURE 3, the metallic ring 26 comprises a hollow cylinder having a lower end 57 of reduced outer diameter and an upper end or well 58 of increased inner diameter. A rubber of plastic O ring 54 is slidably received in the well 58. An aperture 59 is formed in the upper portion of the ring 26 just below the well 58. An annular water chamber 60 is formed between the inner and outer walls of ring 26 and is provided with inlet and outlet pipes 61 and 62 respectively, which receive inlet and outlet lines 31 and 32 respectively. The cylindrical space within the metallic ring provided by the well 58 and the inner diameter therebelow forms a blocking chamber 63. A collar 64 having an annular flange 65 about its upper end has its lower end snugly received in the aperture 34 with support provided to the underside of the flange 65 by the rim around the aperture 34. The lower end 57 of the ring 26 is snugly received in the collar 64 with the underside of the increased outer diameter portion resting on top of the flange 65. The bottom portion of the end 58 is threaded and is of sufficient length to protrude through the aforesaid collar and be secured by a nut 66 and washer 68 against the underside of the icico 18

As best seen in FIGURES 2 and 3, a hollow cylindrical sleeve 70 is slidably received within the metallic ring 26 and has teeth forming a rack 72 along a substantial portion of the length of its outer wall. A shaft 74 having the ejector lever 27 rigidly secured to its outer end protrudes through an opening in the side wall 12 and is rotatably supported in a support 76. The support 76 is rigidly secured to the inside of the front wall 16. The inner end of the shaft 74 has teeth formed about its periphery to provide a pinion 78. In the assembled position, the pinion 78 engages the rack 72 to move the sleeve 70 up and down within the ring 26 in response to movement of the lever 22 by an operator. Rigidly fitted over the top portion of the sleeve 70 is a translucent plastic cap 80 having a rounded nib 82 formed centrally on its top surface. The outer side walls of the cap 80 are snug but slidable within the axial bore of the metallic ring 26. The top surface of the cap forms the bottom of the blocking chamber 63. Scored index lines 84 radiate outwardly from the base of the nib 82. The lines 84 are spaced 90° apart. A conventional light bulb 86 of appropriate size is mounted centrally below the sleeve 70 in order to project light upwardly to the nib 80 where the light will be diffused to illuminate the blocking chamber 63 and to accentuate the score lines 84.

Within the housing 10 and beneath the lid 14 is a bowlshaped heated reservoir 88 for holding the metallic blocking alloy. An aperture 90 is located on the lower portion of the front wall of the reservoir. Rigidly mounted on the front wall is a pump housing 92. The housing 92 65 has a passageway 94 which has its inlet end in registration with the aperture 92 and its outlet end passing upwardly through its top. Intermediate the ends of the passageway is an enlarged cylindrical chamber 96 open at one end. 70 Two ball-check valves 98 and 100 are disposed on opposite sides of the chamber 96. Both valves 98 and 100 will permit liquid flow in a direction away from the res3,468,366 ervoir 88 but not back again. As best seen in FIGURE 5, a diaphragm 102 of resilient material such as rubber or plastic is rigidly secured to the housing over the open end of the chamber 96 by a metal cap 104. The cap 104 has a cylindrical opening through which a plunger 106 is slidably disposed. The plunger has enlarged ends 108 and 109 and is spring biased by a spring 110. The enlarged outer end of the plunger 108 is in engagement with a cam 112 formed on the end of a vertical shaft 116. The shaft 116 extends upward through an opening in the face ₁₀18 and is rigidly connected at its top to the injector lever 22. As is readily seen, rotation of the lever 22 will rotate the cam 112 and move the plunger 106. Inward movement of the plunger 106 will cause like inward movement of the diaphragm 102. The resulting compressive force within 15 the chamber 96 will force the alloy through the passageway in the single direction allowed by the ball check valves 98 and 100. Outward movement by the plunger is assisted by the spring 110.

A cylindrical block 118 is rigidly secured to the top of 20 the pump housing 92 and extends upwardly through the opening 36 in the face 18. A passageway 94' which is in registry with the passageway 94 extends through the block 118 from its bottom upwards to a point of egress 119 on its upper from portion. The insulator 24 is a hollow 25 cylindrical member closed at its upper end and snugly received over the block 118. An aperture 120 on the upper portion of the side wall of the insulator is placed in registry with the egress opening 119 in the block 118. The insulator may be made of plastic or any other material 30 which will efficiently prevent the transfer to heat.

An extension tube 122 has one end rigidly secured in the aperture 59 of the metal ring 26 and the other end rigidly secured to the egress opening 119 in the block 118. The tube provides final communication between the 35 passageway 94' and the blocking chamber 63.

In operation, the blocking device is prepared for use by throwing the toggle switch 28 which will allow conventional house current electricity to operate standard heating elements (not shown) within the reservoir 88. The 40 alloy within the reservoir is a low melting point metal alloy that will successfully furnish a firm bond between lens and block and which is known to the prior art. The alloy will remain in a molten state at temperatures within a range of 165° to 175° F. Actuation of the toggle switch 45 28 will also activate a pump (not shown) to circulate water through the lines 31, 32 and the water chamber 60.

A lens L to be blocked is placed on top of the metal ring with its concave surface upward. The pressure lever 20 is rotated to hold the lens lightly in place. The ejector 50 lever is then rotated to move the plastic cap 80 upwards just beneath the lens. The lens is then centered by matching conventional indices on the lens with the score lines 84. The pressure lever is then rotated to a final clamping pressure selected by the operator. The ejector lever 27 is 55 then operated to lower the sleeve 70 and cap 80 to form the desired sized blocked chamber 63. The liquid metal is then pumped into the blocking chamber by rotating the injector lever 22. The alloy will thus be pumped from the reservoir 88 through the passageways 94, 94' and chamber 96, check valves 98, 100 and extension tube 122. The insulator 24 will serve to keep the alloy temperature within the molten range by preventing heat transfer. The pump will completely fill the blocking chamber with the molten alloy which will then solidify due to the cooling effect of the water circulating in the chamber 60. When the metal has completely solidified and is bonded to the lens, the pressure assembly 20 is released and the lens and block are ejected by rotating the ejector lever 27.

What has been set forth above is intended primarily as exemplary to enable those skilled in the art in the practice of the invention and it should therefore be understood that, within the scope of the appended claim, the invention may be practiced in other ways than as specifically described.

What is new and therefore desired to be protected by