US3353307A

US3353307A - Lens holder for metallic blocking system

Info

Publication number: US3353307A
Application number: US407376A
Authority: US
Inventors: George M J Sarofeen
Original assignee: Titmus Optical Inc
Current assignee: Honeywell Safety Products USA Inc
Priority date: 1964-10-29
Filing date: 1964-10-29
Publication date: 1967-11-21
Anticipated expiration: 1984-11-21

Description

Nov. 21, 1967 5. M. J. SAROFEEN 3,353,307

LENS HOLDER FOR METALLIC BLOCKING SYSTEM Filed Oct. 29, 1964 2 Sheets-Sheet l INVENTOR ATTORNEYS Nov. 21, 1967 G. M. J. SAROFEEZN 3,353,307

LENS HOLDER FOR METALLIC BLOCKING SYSTEM Filed Oct. 29, 1964 2 Sheets-Sheet 2 INVENTOR ATTORN E Y5 United States Patent 3,353,307 LENS HOLDER FOR METALLIC BLOCKING SYSTEM George M. J. Sarofeen, Colonial Heights, Va., assignor to Titmns Optical Company, inc, Petersburg, Va., a corporation of Virginia Filed 0st. 29, 1964, Ser. No. 407,376 27 Claims. (Cl. 51-216) ABSTRACT OF THE DISCLOSURE A lens blocking member having a base and non-flexible side walls which receive a blocking agent, preferably a low-melting metallic blocking agent, and a lens blank spaced from the base wall. The lens block, when mounted on a lens processing apparatus, enables precise axial measurements between the apparatus and points on the surface of the lens. One preferred embodiment includes a flexible gasket having an annular flange which extends above the base wall of the blocking member into engagement with the lens blank for forming a cavity into which the blocking agent is inserted.

This invention relates to a lens blocking member for use in a lens blank blocking system and more particularly to a lens blocking member whereby a precise axial spacing between a surface of the lens blank and the lens processing apparatus may be established.

When grinding a lens blank, the essential problem is one of reference. Multiple curves can only be put on the lens blank if there are reference points so that the particular axes of each curve can be located. Thickness control is another problem which can only be controlled by establishing a means of reference between the grinding apparatus and the lens blank surface itself. The lens blank may be ground to uniform thickness or to a varying thickness which leaves a prismodal effect on the lens blank.

A surface of known curvature may be ground on a lens blank; however, when a surface is ground on the opposite side of the lens blank, it is extremely difl'icult to fix the lens precisely for controlling thickness and prism effects with relation to the first groundsurface and also to fix the lens precisely for establishing accurate axes from which to locate compound curves on the lens blank. By establishing points of reference from one surface of the lens to the block member by which it is held and thereafter through the grinding apparatus to the surface of the grinding lap, the variables in the unground surface may be eliminated from consideration and the lens may be precisely oriented. A precise axial distance is established between the surface of the grinding lap and the base wall of the blocking member through the internal structure of the lens grinding apparatus. Therefore, it is an object of this invention to provide means by which an accurate axial distance may be established between the inwardly facing or previously ground surface of the lens blank and the base wall of the blocking member itself so as to interrelate the positions of the inwardly facing surface of the lens blank and the surface of the grinding lap.

It is a further object of this invention to provide a blocking member for use with a lens blocking system which has a base wall having front and back sides with a side wall depending from the front side of the base wall forming a first cavity between its inwardly facing surface and the front side of the base wall. The cavity preferably receives a lens blank and a low-melting metallic agent, although it 'will be appreciated that any type of blocking agent may be used within the scope of this invention, for holding the lens blank. Means associated with the base wall are provided for engaging and positioning the lens blank at least partially within the cavity and for spacing the lens blank a predetermined known distance from the back side of the base wall so that a precise axial spacing between a .point on the inwardly facing surface of the lens blank and the lens processing apparatus may be established. Accordingly, the thickness between the inwardly facing surface and the outwardly facing surface may be precisely regulated.

It is also an object of this invention to provide the inwardly facing surface of the side wall with means cooperating with the edge of the lens blank for positioning the lens blank in a predetermined orientation within the blocking member.

Further objects of the invention include a means, e.g. a port, to permit the blocking agent to be inserted into the cavity. If a low-melting metallic blocking agent is used, it will be appreciated that for economy purposes the provision of a surface corresponding to the inwardly facing surface of the lens blank is desirable as a means of limiting the volume into which the blocking agent must be inserted.

It is a further object of this invention to provide gasket means associated with the front side of the base wall and having at least an annular wall extending away from the front side so as to form a second cavity concentrically within the first cavity. It will be seen that this gasket means limits the volume of the blocking agent required and also provides protection for the lens positioning means by preventing the blocking agent from covering the positioning means so as to prevent the lens from seating contiguously on the" positioning means, thus varying the otherwise known spaced relationship between the lens blank and the holder.

It is a further object of this invention to provide a gasket means comprising a base means and an annular side wall depending from the base means having its outer edge portion outwardly flared. It will be appreciated that the base portion of the gasket may comprise a flat ring wall which is received in a recess in the front side of the base wall of the blocking member. Accordingly, if the recess for receiving the gasket means is adjacent to the side wall, the base wall of the gasket means may be so configured as to engage the inwardly facing surface of the side wall and the supporting means which may be integrally formed therewith.

As a further object of this invention, the lens supporting means comprise a plurality of lugs spaced along the inwardly facing surface of the side wall of the blocking member.

Still another object of the invention is to provide a blocking member as described having means by which the same may be mounted on the lens processing apparatus O in a predetermined desired orientation. Such mounting means may include a raised handle member depending from the back side of the lens block which has keying means associated therewith so that the supporting element of the processing apparatus can maintain the lens block in a predetermined desired orientation.

These and other objects of this invention are more clearly depicted in the following detailed description having specific reference to the attached drawings in which the embodiments of the invention are shown, not to limit the scope of the invention in any respect but that the principles thereof might be more clearly demonstrated.

In the drawings:

FIGURE 1 is a side elevation view of the blocking member shown schematically in use with a grinding lap and lens processing apparatus;

FIGURE 2 is a top plan view of the blocking member;

FIGURE 3 is a bottom plan view of the blocking member;

FIGURE 4 is a sectional view taken substantially along the lines 44 of FIGURE 2;

FIGURE 5 is a sectional view taken substantially along the lines 55 of FIGURE 2;

FIGURE 6 is a perspective view of the gasket means;

FIGURE 7 is a top plan view of a modified blocking member;

FIGURE 8 is a sectional view taken substantially along the lines 88 of FIGURE 7;

FIGURE 9 is a bottom plan view of the modified blocking member shown in FIGURE 7; and

FIGURE 10 is a fragmentary sectional view of the blocking member shown in use with a polishing lap.

In FIGURE 1, the improved lens blank blocking member is shown schematically in use with a grinding lap 22. The broken line 24 and box 25 represent the lens processing apparatus carrying the grinding lap and which measures and establishes the surface 26 of the blocking member 20 from the lap 22, in a precisely measured relationshi-p, by knowing the established size and shape of the grinding lap. It will be seen, therefore, that the lens can be exactly positioned within the blocking member 20 such that a known dimensional relationship exists between the back surface 26 of the blocking member and the innermost surface 27 of the lens 30 which, as illustrated in FIGURE 5, is a convex surface. Accordingly, the lens may be placed in engagement with the grinding lap while accurately controlling the thickness of the lens through knowing the distance of the convex surface 27 of the lens from the surface 28 of the grinding lap.

As shown more particularly in FIGURES 2 through 5, the lens blocking member 20 has a base wall 32 with a front side 34 and a back side 26. A side wall 36, preferably annular, depends from the front side of the base wall. In the preferable form of the invention, the side wall 36 has an annular inwardly facing surface 38 which, together with the front side 34 of the base wall, forms a cavity 40 therebetween for receiving a blocking agent 42, preferably a low-melting metallic blocking agent, and a lens blank 30.

In the preferred embodiment of the invention, the front side 34 of the base wall has a concave surface 44 formed thereon approximately conforming to the curvature of the convex surface 27 of the lens 30 which is inserted into the holder, so as to limit the amount of low-melting blocking agent needed. It will be appreciated, however, that the concave surface of a lens blank may be received 'within the blocking member such that a convex surface is ground on the exposed or outwardly facing surface of the lens blank. In this situation, the front side 34 may be convex so as to reduce the amount of required blocking agent. Furthermore, at least one opening or port 46 ex- :tends through the base wall 32 to permit introduction of the low-melting metallic blocking agent into the cavity 40. The blocking member 20 also includes lugs or bosses 50 associated with the base wall for engaging and positionin g a lens blank at least partially within the cavity 40 and spaced a predetermined known distance, as at 48, from the back side 26 of the lens blank whereby a precise axial spacing between the inwardly facing surface 27 on the lens blank and the back side 26 of the blocking member may be established.

Preferably the lugs 54) are also associated with the side wall, as shown, although it will be appreciated that the lugs 50 may be supported solely by the base wall 32 and be positioned inwardly of the side wall.

In one embodiment of the invention the lens blank is engaged and positioned by a plurality of lugs 50 preferably integrally connected to the side wall 36 and extending downwardly into engagement with the front side of the base wall. As illustrated, it will be seen that these lugs are integrally connected with the inwardly facing surface 38 of the side wall and that there are four lugs equally spaced along this surface. Although it is desirable to have four lugs inasmuch as they precisely represent the extremities of two axes on a compound lens, it will be appreciated that if a spherical lens were being ground, three, live or even more lugs may be used to position the lens.

It it also within the scope of the invention to have a resilient gasket 52 associated with the front side 34 of the base wall 32, for forming a second cavity 56 concentric within the first cavity 40, with the gasket 52 including at least an annular wall 54 extending above the front side 34. The annular wall 54 extends sufficiently above the front side so as to engage the lens blank when the lens blank is received within the blocking member. It will be appreciated that the ports 46 communicate with this second cavity and that the annular wall 54 contains the metallic blocking agent within a smaller volume than the volume represented by the first cavity. Furthermore, the metallic blocking agent is prevented from coming between the lens blank and the lugs 50, for a contiguous engagement of the lens and the lugs is essential within the scope of the invention. Preferably, the gasket 52 is removable so as to enable replacement whenever it becomes worn out.

As illustrated more particularly in FIGURE 6, the gasket 52 associated with the front side comprises an annular base portion 60 and an integral annular flange 62 extending upwardly therefrom. The front side 34 of the base wall has an annular recess 64 for receiving the base portion 60 of the gasket. When the annular base portion is positioned in the recess 64, the annular flange 62 extends upwardly and above the front side 34 of the base wall into a position for engagement with the lens blank when the lens blank is received within the blocking member. In the preferred embodiment of the invention, the annular base portion 60 of the gasket 52 has indentations or notches '66 for engaging the lug means 50. As illustrated, the indentations or notches 66 intersect the outer edge 70 of the base portion 65 and receive the lugs 50.

The annular base portion is preferably ring-shaped having an opening 76 extending axially therethrough. The ring-shaped base portion has an inner edge 78 and an outer edge 70 adapted to fit contiguously with the inwardly facing surface 38 of the side wall 36. The inner surface 82 of the annular flange 62 lies coextensively with the inner edge 78 of the base portion.

The annular flange 62 has its outer annular edge portion 72 outwardly flared so as to provide an effective resilient sealing means with the inwardly facing surface of the lens. Furthermore, as illustrated, the base portion has a substantially greater thickness T than the side wall and the thickness T of the side wall decreases as it extends outwardly from the base wall :for optimum sealing effectiveness.

In the preferable form of the invention, as shown in FIGURE 2, the inwardly facing surface 38 has flattened side portions 84 cooperating with the flattened edges of the usually square lens blank for positioning the lens blank in a predetermined orientation within the blocking member. It will be seen that this is particularly important :for orienting lenses within a blocking member when more than one curve is put on the lens surface. If the inwardly facing surface has a plurality of such flat portions, it will also be appreciated that the outer edge 70 of the base portion of the gasket would be correspondingly flattened so as to fit contiguously therewith.

It is further within the scope of the invention, as shown in FIGURES 2 and 3, to include indented openings 88 in the side wall 36 for applying an instrument means, not shown, inwardly of the side wall to aid in removing the lens from the low-melting blocking agent. An instrument means, such as a narrow blunt-ended metal rod, is inserted inwardly of the side wall and under the lens so that the lens may be knocked free from the low-melting metallic blocking agent by a sharp rap on top of the rod. It will also be appreciated that the outwardly flaring edge 72 can provide a buffer between the instrument rod and the lens blank during this removal operation so as to prevent the lens from being damaged.

The back side 26 of the base wall 32 provides support means for mounting the lens blocking member on a lens processing apparatus in a predetermined desired orientation. Basically, the desired orientation with respect to the thickness of the lens is determined by the fact that the lugs, and hence the lens surface, are exactly spaced from the back side 26 of the blocking member as previously explained. Thus, the thickness of the lens blank is controlled by supporting the back side in a known predetermined spaced orientation from the surface 28 of the grinding lap 22. However, it will be appreciated that in order to control the generation of two or more curved surfaces or the generation of a lens having a prismoidal thickness, it is necessary to provide a means by which the lens may be additionally oriented. Therefore, as illustrated, a raised handle member 94 depending from the back side 26 of the base wall 32 is provided which enables the blocking member to be gripped in an oriented position. The handle means has keying means 96, such as one or more flat sides, associated therewith so that the supporting element of the lens processing apparatus can maintain the lens block in a predetermined desired orientation. It will be appreciated that within the scope of the invention the raised handle member may have various configurations other than those disclosed in the drawings which will accomplish the objects of the invention.

It is further within the scope of this invention to insert a conical spindle receiving means 98, preferably within the handle member, so that in some operations the lens blocking member may be mounted thereby. The conical spindle receiving means 98 is preferably radially centered with respect to the annular inwardly facing surface 38 of the side wall. The blocking member is supported by a spindle, not shown, received within the conical spindle receiving means Q8 when it is desirable, for instancefto remove part of the lens surface uniformly.

FIGURES '7 through 9 illustrate a modified blocking member 20a which is preferably used in grinding spherical curves on a lens blank. As illustrated, the blocking member 20a differs from the blocking member 2%) disclosed in FIGURES 2 through in that lugs 50 for engaging and positioning the lens blank are replaced by an annular led-ge 100a disposed above the front side 34a of the base wall 32a and associated with the base wall 32a and more particularly the back side 26a of the base wall 32a so that a precise axial spacing between a surface of the lens blank and the back side 26a may be established. In the preferred form of the embodiment the ledge 100a is integrally connected to the inwardly facing surface 38a of the side wall 36a and extends radially inwardly and axially downwardly into engagement with the front side 34a of the base wall 32a. As illustrated, the inwardly facing surface may have substantially flat portions 85a for orienting the lens within the blocking member. The means 88a comprises an indented opening 90a which extends inwardly of the side wall and extends below the surface 102a of the annular led-ge ltlila for applying an instrument. Furthermore, as shown more particularly in FIG- URE 9, the raised handle member 94a may be annular inasmuch as it is not necessary to have a precise orientation for the establishment of a spherical curve on the surface of the lens. A conical spindle receiving means 98a may also be received within the raised handle means 94a. Furthermore, similar to the first embodiment of the invention, there is at least one opening or port 46a extending through the base wall and communicating with the cavity 40a formed between the front side 34a of the base wall and the side *wall 36a.

As illustrated in FIGURE 10, one further feature of this invention is the fact the side wall 36 of the blocking member is so configured that it extends beyond the edge of the lens blank during the polishing process. When ground to the ultimate desired thickness, it may be necessary to grind away some of the side wall of the blocking member, as illustrated at 102, such that the outer edge of the side wall conforms to the curved surface being ground on the lens. During the polishing operation this side wall protects the outer edge 104 of the lens from being slightly rounded off due to impingement of the lens leading edge on the polishing pad 106. Even though the outer edge of the lens blank may be removed before actual use, nevertheless the rounding of this edge might cause an aberration which lowers the quality rating of the lens. The protective side wall of the blocking device 2t, avoids this aberration by depressing the polishing pad prior to its contact with the lens itself.

While a preferred form of the invention has been illustrated in the drawings and discussed above, it should be adequately clear that considerable modifications may be made thereto without departing from the principles of the invention. Therefore, the foregoing should be considered in an illustrative sense rather than a limiting sense, and accordingly the extent of this invention should be limited only by the spirit and scope of the claims appended hereto.

What is claimed is:

1. A lens blocking member for holding a lens blank and for use with a lens blocking system of the character described employing a blocking agent comprising: a base wall having front and back sides and a continuous periph ery; a relatively rigid side wall depending from said front side, integrally formed therewith, and joined to said base wall throughout substantially all of the periphery of said base wall, said side wall having an annular inwardly facing surface, said inwardly facing surface and said front side defining a first cavity within which a lens blank is adapted to be peripherally enclosed; axially centrally located mounting means associated with said back side of said base wall for mounting said lens blocking member on a lens processing apparatus in a predetermined desired orientation; means associated with said base wall adapted to engageand position said lens blank within said first cavity; and means associated with said front side of said base wall forming a second cavity concentrically within said first cavity, said means including at least a flexible annular wall extending above said front side and adapted to engage said lens blank when said lens blank is received within said blocking member.

2. The blocking member as defined in claim 1 wherein said base wall has at least one port extending therethrough for enabling said blocking agent to be inserted into said first cavity through said base Wall.

3. The blocking member as defined in claim 1 wherein said side wall includes means for applying an instrument means inwardly of said side wall to aid in removing said lens blank from said low-melting metallic blocking agent.

4. The blocking member as defined in claim 3 wherein said instrument applying means comprises an opening extending through said side wall for inserting an instrument means inwardly of said side wall to aid in removing 5. The blocking member as defined in claim 1 wherein said means associated with said front side is removable so as to enable replacement.

6. The blocking member as defined in claim 1 wherein said means associated with said front side comprises resil ient gasket means having an annular base portion and an integral annular flange extending upwardly therefrom and wherein said front side of said base wall has an annular recess formed therein for receiving said annular base portion of said gasket means, said annular flange extending upwardly and above said front side into a position for engagement with said lens blank when said lens blank is received within said blocking member.

7. The blocking member as defined in claim 6 wherein said gasket means comprises an annular base portion having an edge means for receiving said means for engaging and positioning said lens blank within said first cavity, and an annular wall portion integrally depending from said base portion and having its outer annular edge portion outwardly flared.

8. The blocking member as defined in claim 7 wherein said gasket means comprises a base wall having an outer edge with a plurality of substantially fiat edge portions and a plurality of recesses intersecting said edge for receiving said means for engaging and positioning said lens blank within said first cavity, and an annular side wall integrally depending from said base wall having its free outer annular edge portion outwardly flared.

9. The blocking member as defined in claim 1 wherein said lens blank engaging and positioning means comprises a plurality of lugs connected with said inwardly facing surface.

10. The blocking member as defined in claim 9 wherein there are four lugs equally spaced along said inwardly facing surface.

11. The blocking member as defined in claim 1 wherein said means for mounting said lens blocking member on a lens processing apparatus in a predetermined desired orientation comprises the back surface of said base wall and a raised handle member depending from said back surface.

12. The blocking member as defined in claim 11 wherein said raised handle member has keying means for enabling said blocking member to be positioned in a predetermined orientation.

13. The blocking member as defined in claim 12 wherein said keying means comprises said handle member having at least two straight parallel side wall portions by "which said blocking member can be gripped.

14. The blocking member as defined in claim 11 wherein said mounting means additionally comprises a conical spindle receiving means rigidly secured in said raised lhandle member.

15. The blocking member as defined in claim 14 wherein said spindle receiving means is radially centered with respect to said annular inwardly facing surface of said :side wall.

16. A lens blocking member for holding a lens blank and for use with a lens blocking system of the character described employing a blocking agent comprising: a base wall having front and back sides and a continuous periphery; a relatively rigid side wall depending from said front side, integrally formed therewith, and joined to said base wall throughout substantially all of the periphery of said base wall, said side wall having an annular inwardly facing surface, said inwardly facing surface and said front side defining a first cavity within which a lens blank is adapted to be peripherally enclosed; axially centrally located mounting means associated with said back side of said base wall for mounting said lens blocking member on a lens processing apparatus in a predetermined desired orientation; means associated with said base wall having a portion thereof defining a second cavity within said first cavity and another portion thereof defining support means adapted to support said lens blank, said base wall having at least one port extending therethrough for enabling a blocking agent to be inserted into said second cavity through said base wall; and means defining an instrumentreceiving opening through said side wall into said first cavity and partially into said portion defining said support means so that an instrument can be positioned outside said second cavity and in engagement with a surface of said lens blank when said lens blank is positioned within said first cavity for removing said lens blank from said lens blocking member.

17. The blocking member as defined in claim 16 wherein said front side of said base Wall has a concave surface.

18. The blocking member as defined in claim 16 wherein said annular inwardly facing surface has means adapted to cooperate with the edge of said lens blank for positioning said lens blank in a predetermined orientation within said blocking member.

19. The blocking member as defined in claim 18 wherein said positioning means comprises said inwardly facing surface of said side wall having at least a portion thereof comprising opposed parallel surfaces adapted to engage and hold said edge of said lens blank in a predetermined orientation within said blocking member.

20. The blocking member as defined in claim 16 wherein said lens blank engaging and positioning means comprises an annular ledge disposed above said front side of said base wall and integrally connected with said inwardly facing surface of said side wall.

21. In a lens blocking member for use with a lens blank blocking system having a base wall with front and back sides, a relatively rigid side wall depending from said front side defining a cavity between said side wall and said front side of said base wall adapted to receive a lens blank, and an axially centrally located mounting means associated with said back side for mounting said lens blocking member on a lens processing apparatus, the improvement comprising: means associated with said front side of said base wall having a flem'ble annular flange depending from said front side and defining second cavity means concentrically within said first cavity, said annular flange adapted to engage said lens blank when said lens blank is received within said holder, said second cavity means constructed and arranged to receive a blocking agent, and means defining a conduit between the exterior of said blocking member and said second cavity means for permitting the blocking agent to be inserted into said second cavity means.

22. The improvement as defined in claim 21 wherein said cavity defining means associated with said front side is removable so as to enable replacement.

23. The improvement as defined in claim 21 wherein said second cavity defining means associated with said front side includes an annular ring-like base member integrally connected to said annular flange and wherein said front side of said base wall has an annular recess formed therein for receiving said annular base member.

24. The improvement as defined in claim 21 wherein said annular flange has its free outer annular edge portion outwardly flared.

25. A gasket for use with blocking members employing a blocking agent comprising: base means having at least an outer edge, a front side and a rear side, and an annular side wall depending from said front side of said base means and having its outer annular edge portion outwardly flared, said annular side wall defining a central space radially inwardly thereof and said base means having means defining an axially directed opening communicating said rear side of said base means with said space; said base means being ring-shaped having an inner edge and an outer edge, and wherein the inner surface of said side wall is coextensive with said inner edge.

26. The gasket as defined in claim 25 wherein the thick- 9 ness of said base means is substantially greater than the thickness of said side wall.

27. A gasket for use with blocking members employing a blocking agent comprising: base means having at least an outer edge, a front side and a rear side, and an annular side wall depending from said front side of said base means and having its outer annular edge portion outwardly flared, said annular side wall defining a central space radially inwardly thereof and said base means having means defining an axially directed opening communicating said rear side of said base means with said space; said outer edge of said base means having a plurality of substantially fiat edge portions and a plurality of indentations intersecting said edge portions for engaging complementary surfaces of the blocking member.

References Cited UNITED STATES PATENTS 1,119,111 12/1914 PelloW 51-216 2,264,392 12/1941 McClernon 51217 2,441,472 5/ 1948 DAvaucourt 51216 2,597,543 5/1952 Suben 51-216 X 3,032,936 5/1962 Voice 51216 X 3,192,676 7/1965 Buckminster 5l--216 FOREIGN PATENTS 162,308 2/1949 Austria 51217 HAROLD D. WHITEHEAD, Primary Examiner.

Claims

16. A LENS BLOCKING MEMBER FOR HOLDING A LENS BLANK AND FOR USE WITH A LENS BLOCKING SYSTEM OF THE CHARACTER DESCRIBED EMPLOYING A BLOCKING AGENT COMPRISING: A BASE WALL HAVING FRONT AND BACK SIDES AND A CONTINUOUS PERIPHERY; A RELATIVELY RIGID SIDE WALL DEPENDING FROM SAID FRONT SIDE, INTEGRALLY FORMED THEREWITH, AND JOINED TO SAID BASE WALL THROUGHOUT SUBSTANTIALLY ALL OF THE PERIPHERY OF SAID BASE WALL, SAID SIDE WALL HAVING AN ANNULAR INWARDLY FACING SURFACE, SAID INWARDLY FACING SURFACE AND SAID FRONT SIDE DEFINING A FIRST CAVITY WITHIN WHICH A LENS BLANK IS ADAPTED TO BE PERIPHERALLY ENCLOSED; AXIALLY CENTRALLY LOCATED MOUNTING MEANS ASSOCIATED WITH SAID BACK SIDE OF SAID BASE WALL FOR MOUNTING SAID LENS BLOCKING MEMBER ON A LENS PROCESSING APPARATUS IN A PREDETERMINED DESIRED ORIENTATION; MEANS ASSOCIATED WITH AID BASE WALL HAVING A PORTION THEREOF DEFINING A SECOND CAVITY WITHIN SAID FIRST CAVITY AND ANOTHER PORTION THEREOF DEFINING SUPPORT MEANS ADAPTED TO SUPPORT SAID LENS BLANK, SAID BASE WALL HAVING