US3093939A

US3093939A - Surfacing apparatus

Info

Publication number: US3093939A
Application number: US121786A
Authority: US
Inventors: Ernest T Dalton
Original assignee: American Optical Corp
Current assignee: American Optical Corp
Priority date: 1961-07-03
Filing date: 1961-07-03
Publication date: 1963-06-18
Anticipated expiration: 1980-06-18
Also published as: CH428478A; GB933640A; FR1332200A

Description

June 18, 1963 E. T. DALTON 3,093,939

SURFACING APPARATUS Filed July 3, 1961 3 Sheets-Sheet 1 INVENTOIZ $5 3 I se/vesr r DALTON ATTORNEY June 18, 1963 E. T. DALTON 3,093,939

SURFACING APPARATUS Filed July 3, 1961 3 Sheets-Sheet 2 [Ii-nu NV E NTOE ERNEST Z DRLTON ATTO Q N EY June 18, 1963 E. T. DALTON SURFACING APPARATUS Filed July 3. 1961 3 SheetsSheet 3 &

I8Z H I I92 2 /92 /88 L ,9 I I A! a INVENTOIZ EENE ST 7? D01. TON

ATTORNEY United States atcnt Ofiice 3,093,939 Patented June 18, 1963 3,093,939 SURFACHNG APPARATUS Ernest T. Dalton, Southhridge, Mass, assignor to American Optical Company, Southbridge, Mass, an association of Massachusetts Filed July 3, 1961, Ser. No. 121,786 16 Claims. (Ci. 51-124) This invention relates to apparatus for surfacing articles such as lens blanks or the like and has particular reference to improvements in high-speed surfacing equipment which is designed more specifically for producing surfaces of compound curvature upon such articles.

Optical surfaces of compound curvature are usually formed on lens blanks or like articles by initially grinding a side of the blanks to a predetermined toric shape and thereafter optically polishing the ground surface by placing the same in engagement with a preformed tool or lap or the like having a surface curvature matching that which has been ground upon the lens blank. The major meridians of the toric surface curvature on the lens blank are maintained parallel to the matching meridians of curvature on the tool at all times and a polishing medium is applied to the tool surface so as to come between it and the surface of the lens blank to be polished. By producing relative motion between the lens blank and tool Without disturbing the parallel relationship of the above-mentioned meridians, the surface of the lens blank is polished.

In general, the time required to produce a polished surface of optical quality is dependent upon the amount of relative motion which can be produced between the lens blank and toolwithout destroying the accuracy of the compound surface curvature and the rate at which the motion is imparted. That is, with other factors such as the texture of the initially ground surface, the pressure applied to the work piece and the particular characteristics of the polishing medium being considered to be the same in all cases, greater amounts of relative motion and faster speeds thereof will reduce the polishing time accordingly.

In certain practices, lens blanks having relatively rough (ground surfaces are fine ground before polishing and this fining operation is usually accomplished in the manner described above for polishing simply by substituting a grinding medium for the above-rnentioned polishing medium.

In toric surfacing operations, the respective major and minor meridians or axes of the compound surface curvacure on a toric lens blank being processed must be maintained parallel to the respective matching meridians or axes of the preformed :toric working surface of the tool at all times and, because of this, relatively complex and ungainly harness arrangements or the like have been used heretofore to support and retain the lens blanks and tools in proper oriented relation with each other during surfacing operations. The complex nature of prwently used axis-aligning devices has not made it possible to provide a balanced piece of equipment which could be operated at relatively high speeds. That is, conventional axis-aligning devices have comprised various off-set arms and yokelike holding members or the like for supporting either the tool or work piece and at least some of these members have been resiliently or otherwise movably held by flexible arms or pivotal connections or the like. When rotated at relatively slow speeds, devices of this type perform their intended function but, at high speeds of rotation, centrifugal forces and other effects such as vibration due to imbalance of the equipment cause mis-alignment of the Work holder and tool during surfacing with the result of producing inaccurately curved and poorly textured surfaces or otherwise inferior lens blanks.

In order to keep abreast with the ever increasing demands for more efficient and increased production in the lens manufacturing field, it is essential that lens blanks surfacing operations be speeded up and improved without sacrifice of end product quality and with a view to improving product quality. This, obviously, cannot be accomplished successfully with conventional equipment designed for relatively slow-speed operations and wherein the problems of balance and other design factors essential to high-speed operations were not properly dealt with.

The present invention, in dealing with the factors involving high-speed surfacing methods and operations, offers a solution to the above-mentioned and other problems in this field and, accordingly, it is a principal object of the invention to provide novel means for surfacing toric lens blanks or like articles with increased efiiciency and precision.

Another object is to provide, in surfacing equipment of the above character, an improved rotatable tool and Work supporting arrangement designed for substantially centrifugally balanced operation when rotated at relatively high speeds.

Another object is to provide, as a part of said tool and work supporting arrangement, novel resilient holding means for supporting a work piece in fixed oriented relation with an abrading tool at all times while permitting a substantial amount of freedom of lateral oscillatory movement between said workpiece and tool without sacrifice of product quality.

Another object is to provide a tool and work holding device of the above character for supporting a tool member and work member in abrading relation with each other and which is rotatable as a unit about a. fixed axis, said device embodying an inner rigid support for a first of said members positioned coaxially with said axis of rotation and an outer resilient support surrounding and attached to said rigid support at one end with its opposite and being free and adapted to receive and support the other of said members in relatively free floating fashion upon said first member.

Another object is to provide a work holding device of the above character wherein said outer resilient support is constructed and arranged so as to be in balance and substantially concentric with the axis of rotation of the device and is so characterized as to resist tortional or other forces tending to produce orbital mis-alignment of its opposite ends while being otherwise universally flexible.

Another object is to provide as said outer resilient support, a coiled spring-shaped member having convolutes so geometrically proportioned as to render said member substantially immune to centrifugal and tortional or other forces tending to produce orbital misalignment of the convolutes thereof under the greatest rotational rates and pressures to which said member might be subjected during an abrading operation.

Another object is to provide, as a substitute for said spring-like member, a cylindrical bellows-type of structure.

A further object is to provide through the use of arrangements such as generalized above, simple, highly efficient and economical toric surfacing apparatus which is designed to perform high-speed optical surfacing operations with precision, dependability, and unusual efiiciency.

Other objects and advantages of the invention will become apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective illustration of a lens blank which is to be finished in accordance with this invention;

FIG. 2 is a perspective view of a preferred lap or tool used in conjunction with the apparatus of the invention for finishing a surface curvature upon a lens blank or the like such as shown in (FIG. 1;

3 =FIG. 3 is a side elevational view of a preferred form of surfacing apparatus with portions broken away to reveal featured sections thereof;

,FIG. 4 is a front elevational view of the apparatus shown in FIG. 3; FIG. 5 is an enlarged cross-sectional view taken approximately along line 5-5 of FIG. 3 looking in the direction of the arrows; FIG. 6 is a'view of a portion of the apparatus shown in FIG. 3 taken from the position of line 66 on FIG. 3 and looking in the direction indicated by the arrows;

FIG. 7 is an enlarged fragmentary cross-sectional view taken approximately along line 7--7 of FIG. 5;

FIG. 8 is a view generally similar to FIG. 7 showing an alternative arrangement of that portion of the apparatus; and

FIGS. 9, 10, 11 and 12 are fragmentary views of different modifications of the invention.

The'present invention relates generally to apparatus for surfacing articles such as lens blanks or the like and the drawings illustrate a preferred form of such equipment in which is featured a novel lens blank and tool supporting fixture 20 (see FIGS. 3, 4, and 5) for holding a lens blank and tool in fixed pro-established orbitally aligned relation with each other at all times. It will become apparent hereinafter that the fixture 20, which is rotated as a unit during a surfacing operation, provides a well balanced piece of rotary equipment which permtis high-speed operations to be accomplished with a minimum of vibration or other effects of imbalance which would be detrimental to the accuracy of curvature and facing machines but, for purposes of illustration, it has been shown in FIGS. 3-7 in a position of use on a preferred form of apparatus wherein the combination of the apparatus illustrated and the fixture 20 provides a unique, compact and highly eflicient lens-surfacing machine 22. The apparatus upon which the rotary fixture 20 is mounted will be described in detail first to provide a better understanding of the construction, purpose and function of the fixture 20 whose description will follow.

Referring more particularly to (FIGS. 3 and 4, it will be seen that the surfacing machine 22 comprises a base 24 preferably having a hollow interior and an overhanging head part 26 pivotally connected to the base 24 by means of H-shaped links 28 and 30 (see FIGS. 3 and 4) which are pivotally attached to

pivot blocks

32 and 34 on the respective head and base parts of the machine. The

blocks

32 and 34 and their respective links 28 and 30 are interconnected by pivot pins '36 and the blocks 34 are bolted or otherwise fixed to the base 24. The blocks 32, which will be considered to be a part of the head 26, are interconnected by horizontally disposed rods 38 and 40 which are fitted into

bores

42 and 44 respectively in enlarged bosses 46 formed on the uppermost portion of each of the blocks 32. The rods 38 and 40 are securely clamped adjacent their opposite ends in the bosses 46 of the blocks 32 by set screws or the like 48 and are so arranged (see FIG. 4) as to place the uppermost ends of the links 28 and 30 at a distance apart which is substantially equal to the distance between the lowermost ends of said links.

The composite arrangement of the links 28 and 30, the pivot blocks 32 and the rods 38 and 40 [forms a cradle upon which an overhanging portion 50 of. the head 26 is mounted so as to pivot about the rod 38. The cradle, being so pivotally mounted to the base 24, provides means for oscillating the head 26 laterally or in a sidewise direction during a surfacing operation as will be explained in detail hereinafter. The overhanging portion 50 of the head 26 embodies a main supporting casting 52 which is provided with a pair of depending split bearings 54 fitted to the forward rod 38. The bearings 54 are so machined and fitted to the rod 38 as to provide a secure, vibrationless connection while permitting relatively free pivotal movement of the overhanging portion 50 of the head 26 about said rod 38. The overhanging portion 50 of the head 26, while being free to pivot about the rod 38 is fixed against lateral movement along the rod 38 by means of suitable stop means which, for purposes of illustration, is shown as being a collar 51 surrounding the rod 38 between the split bearings 54. Once the overhanging portion 50 of the head 26 is placed at a desired location along the rod 38, the collar 51 is locked to the rod 38 by set screws or the like 51a.

It is pointed out at this time that all pivotal or solid connections which are made between the various parts of the machine 22 are accurately machined so as to provide intimate, secure and vibrationless connections. Furthermore, the various parts described hereinabove and those to be subsequently described are designed to be of such rigidity as to minimize vibrations during the operation of the machine.

Referring again to the overhanging portion 50 of the head 26, it will be seen in FIGS. 3 and 4 that there is attached to the forward end of the casting 52, a spindle housing 56 in which is journaled a rotatable spindle 58 (see FIG. 5). The spindle 58 will be referred to hereinafter as the upper spindle and it is driven by a motor 60 through

pulleys

62 and 64 and an interconnecting belt 66. The motor 60 is mounted upon the casting 52 adjacent the rear portion of the head 26 so as to partially counterbalance the portion of the head 26 which overhangs the forward section of the machine.

The spindle housing 56 is provided with an integral 'rearwardly extending mounting bracket 68 which is attached to the casting 52 with a bolt 70. The adjoining surfaces of the mounting bracket 68 and the casting 52 are arcuately shaped and matched in curvature to fit together. These arcuate interfitting shapes of the casting 52 and bracket 68 permit the spindle housing 56 to be tilted slightly by sliding the spindle housing mounting 'bracket168 to one side or the other of a mid-position where the housing axis would normally be vertical. A slot 72 in the mounting bracket 68 allows for a desired lateral adjustment of the spindle housing and'the bolt 70 is immovably mounted in the casting 52 so that, by loosing the nut 71, the spindle housing bracket 68 is free to slide laterally for purposes of adjusting the tilt of the spindle housing. When a desired adjustment is made, the nut 71 is tightened to retain the adjustment. The respective surfaces 74 and 76 of the casting 52 and mounting bracket 68 are curved to a radius r (see FIG. 4) approximately equal to the distance between said surfaces and a point 77 therebelow approximately at the level of the average center of curvature of a lens blank surface to be worked upon in the fixture 20. This will be discussed in greater detail hereinafter wherein it will become apparent that the particular curvature of the

surfaces

74 and 76 are arranged to cause the spindle housing to be tilted approximately radially about the center of the average curvature of a lens blank surface to be worked upon. This is to cause the axis of the spindle 58 to be directed approximately normal to a tangent to the lens blank surface at the point of intersection of the upper spindle axis with said lens blank surface and thus pressure exerted upon the lens blank by the head 26 is directed substantially evenly during lateral oscillation of the lens blank as a surfacing operation is performed. This will be explained in greater which the member 88 is threaded (see FIG. 3).

detail hereinafter in conjunction with a description relating to the operation of the apparatus of the invention.

, In order to lift and lower the overhanging portion 50 of the head 26 so as to permit the insertion or removal of work pieces from the fixture 20, an air cylinder 78 is secured by bolts or the like 80 to the rear side of the base 24 and its piston rod 82 is connected to the casting 52 of the head 26 by a flexible cable or cord or the like 84. When the air cylinder 78 is actuated, its piston rod 82 is drawn downwardly producing a pull on the cord 84 which causes the overhanging portion 50 of the head to pivot on the rod 38 and lift the spindle housing away from the fixture 20. With the machine in operating position, the piston rod 82 of the air cylinder 78 is raised as shown in FIG. 3 to provide slack in the cord 84 thereby allowing spindle housing 56 to lower to an operating position wherein the lens blank will freely engage the tool. Since it is required that a controlled pressure he applied to a lens blank or work piece which is being surfaced, a spring 86 is connected under tension between the base 24 and the overhanging portion 50 of the head 26. The spring 86 is held under tension by

hooklike members

88 and 90 attached to its opposite ends and the member 90 is secured with a bracket 92 to the base 24 while the member 88 is adjustable vertically to increase or decrease the tension of the spring 86. This adjustment is accomplished by means of an internally threaded adjusting bolt 94 iInlto e bolt 94 is, in itself, rotatable in a vertical sleeve-like fitting 96 which is integral with the casting 52. Rotation of the "bolt 94in the fitting 96 causes the threaded portion 93 of the hook-like member to advance into or retract from the internally threaded area of the bolt 94 (depending upon its direction of rotation) so as to bring about a raising or lowering of the hook-like member 88 to increase or decrease the tension of the spring 86 as required.

The machine 22 is provided with a lower spindle housing 100 which isbolted or otherwise attached to the upper portion of the base 24 (see FIGS. 3, 4 and 5) and extends upwardly through the top of the base 24 toward the upper spindle 58.

In the lower spindle housing 100, there is journaled a lower spindle 102 {see FIG. 5) which is rotatably driven by a motor 104 through a belt and pulley arrangement embodying a pulley 106 on the motor 104, a pulley 108 connected to the lower spindle 102 and an interconnecting belt 110.

The upper and lower portions of the lower spindle 102 are journaled in the housing 190 by means of bearings such as shown at 112 in FIG. 5 and the uppermost end of the spindle 102 is threaded at 114. A first adaptor 116 is threadedly connected to the upper end of the spindle 102 so as to be rotatable therewith and a second adaptor 118 for receiving and supporting a tool 129 is also carried by and rotatable with the lower spindle 102. This second adaptor 118 which will be referred to hereinafter as the tool adaptor 118 is provided with a tapered upper section 122 for receiving the tool 120 and has an intermediate annular shoulder 124 with a reduced cylindrically shaped depending portion 126 which is fitted into a similarly shaped recess 123 formed in the upper end of the spindle 102. The tool adaptor 118 is held in place on the spindle 102 by means of a bolt 130 which extends substantially coaxially therethrough and is threaded into the spindle 102 adjacent the base of the recess 128 therein. The head of the bolt 130 is recessed into the tool adaptor 118 as shown in FIG. 5 and a locating pin 132 which is fixed in the spindle 102 so as to extend upwardly into the recess 128 is arranged to enter a receiving opening 134 in the tool adaptor 118 to locate the adaptor in a fixed predetermined oriented relation with spindle 102. The locating pin 132 also functions to prevent possible rotational misalignment or slippage between the spindle 102 and tool required in a surfacing operation.

adaptor 118 thereby assuring that the adaptor and spindle will rotate together as a common unit and the holding bolt will not tend to become loosened. Also, on the tool adaptor 118 there is provided a keying pin 136 (see FIG. 3) which is press-fitted or otherwise secured in an appropriately formed lateral opening 137 in the tapered section 122 thereof. The tool 120 which has an axially aligned tapered opening 138 adapted to interfit with the tapered section 122 of the adaptor 118 is provided with a key slot 140 (see FIGS. 2 and 3) which fits over the pin when the tool 1120 is placed upon the adaptor 118. The key slot and pin 136 prevent rotational slippage from taking place between the tool 124} and adaptor 118 and the combination of the above-described parts causes the spindle 120,

adaptors

116 and 118 and tool 120 to rotate together as an integral or common unit when the spindle 102 is rotated.

The fixture 211 which will be considered herein to include the adaptors 116 and 1 18 and the tool 120 further comprises an annular base plate 142 which is fitted onto a shoulder 144 formed on the first adaptor 116 as shown best in FIG. 5. The base plate 142 is secured to the first adaptor 116 by connecting bolts or studs 146 and is shaped to have an outer annular platform-like portion 147 depending from the points of its connection to the adaptor 115. This platform portion 147 is concentric with the axis of the spindle 102 and carries an upstanding resil ient coupler 148 which supports and resiliently connects an upper work holding assembly 150 to the base plate 142 of the fixture 20.

The coupler 148, in its preferred form as shown in FIGS. 3, 4 and 5, is constructed of a resilient metal such as cold rolled steel, stainless steel or other alloys common to the manufacture of articles such as coiled springs and, being in the general configuration of a coil spring, the coupler 148 is constructed in accordance with known techniques used in the manufacture of such items so as to have a desired degree of rigidity in tending to naturally support the work-holding assembly 150 at a desired level relative to the total 120 while also being relatively freely and substantially evenly or equally flexible in all meridians to permit its uppermost end to move laterally and tilt as The coupler 148 is further characterized to be relatively easily compressible for purposes of permitting the work piece to remain in engagement with the tool at all times during a. surfacing operation as will be explained more in detail hereinafter.

The coupler 14$ is, in addition to the above, characterized to be substantially immune to tortional forces tending to wind or unwind its convolutes 152 as a result of pressures applied between the work piece and tool 120 or forces caused by rotation of the fixture at relatively high speeds during operation of the machine 22.

These characteristics of the coupler 148 are achieved by proper design of the shape and size of the convolutes 152 in accordance with the material used in its construction.

By way of example, it has been found that a coupler 148 such as shown in FIGS. 3, 4 and 5 which is formed of cold rolled steel or stainless steel to an outer diameter of approximately 6 inches should have convolutes 15 2 measuring approximately from /s to inches in thickness and approximately /8 inches in width, giving the coupling 148 an inner diameter of approximately 4% inches. If formed of other metals, these dimensions would be adjusted in accordance with the particular characteristics of the metals selected. The coupler 148 is also preferably constructed so as to have a right-hand wind with a pitch of about of an inch. It is intended to be rotated clockwise, as viewed from above, when driven by the lower spindle 102 since it has been found that articles of this nature are more resistant to orbital mis-alignment of their opposite ends when rotated in the direction of their wind. The lowermost convolute 154 of the coupler 148 is fixed to the base plate 142 by bolts or studs or the like 156 most convolute 158 of the coupler 148 by the bolts or studs 160. Thus, it can be seen that rotation of the spindle 102 will cause the entire fixture 20 including the tool 120 and work-holding assembly 150 to rotate as a unit; the work-holding assembly being driven from the base plate 142 through the resilient coupler 148.

In detail, the work-supporting assembly 150 comprises an annulus 162 which is attached to the uppermost convolute !158 by the studs 160. The annulus 162 is provided with a recess 164 into which a rotatable adjustable collar 166 is coaxially fitted (see FIGS. 4, 5, and 6). The collar 166 is held in place on the annulus 162 by a pair of locking studs 168 extended downwardly through slots 170 provided in the collar 166. The studs 168 are threaded into the recessed portion of the annulus. In FIG. 6, it can be seen that the slots 170 are arcuately shaped to a curvature concentric with the common axis of the annulus 162 and collar 166 so that, with the studs 168 loosened, the collar 166 may be rotated upon the annulus 1 62 within the limits of the slots 170 to adjust the orientation of the collar relative to the tool 120.

In the fabrication of this part of the fixture 20, the collar 166 is fitted to the annulus 162 in a predetermined oriented relation with respect to the tool 120 and the annulus is then drilled and tapped approximately mid-way between the ends of the slots 170 so that, for a fine or more precise alignment inorientation of the work piece holder 150 relative to the tool, the above-mentioned adjustment using the studs 168 and slots 170 may be used in the final adjustment of the fixture 20. This will be explained in more detail in the description of the setting up and operation of the machine 22 which follows.

The collar 166 is provided with a pair of diametrically opposed raised sections 172 through each of which is provided an accurately machined bearing opening 174. These bearing openings 174 are coaxial along a diameter of the collar 166.

A work-supporting yoke 176 is extended between the openings 174 and is supported at its opposite ends by bearing studs 178 which are threaded thereinto (see FIG. The enlarged heads 180 of the studs are carefully machined to fit closely in the openings 174 which function as bearing surfaces for said heads 180 and the yoke 176 is free to pivot about the common axis of the openings 174.

It is pointed out that in order to minimize wear, it is preferable to form the collar 166 and bearing studs 178 of different metals. That is, for example, one of bronze and the other of steel. It is further pointed out that while it is preferable to form practically all parts of the machine 22 of metal, the selection of materials used is made in the conventional manner of machine designing to obtain optimum performance with minimum wear.

The yoke 176 has an enlarged mid-portion 182 in which is centrally located a recessed ball socket 184 adapted to receive the ball-shaped end portion of a crank pin 186 carried by the upper spindle 58. 'It will be noted in FIGS. 4 and 5 that the crank pin 186 is located eccentrically in the depending end of the upper spindle 58 so that rotation of the spindle 58 will cause the crank pin 186 to orbit and,

- when seated in the bearing socket of the yoke, it will cause the work-holding assembly 150 to move accordingly. The work-holding assembly 150, being supported by the rresilient coupling 148 is, of course, free to respond to the orbiting of the crank pin 186.

A work piece such as the lens blank L is supported with its surface s which is to be abraded against the surface t of the tool 120. The lens blank L which ordinarily would be attached to a block 188 as shown in FIGS. 5 and 7 is supported in abrading relation with the tool 120 by means of aligning and holding pins 190 in the yoke 176 which interfit with sockets 192 in the block 188. The lens blank L may be blocked either in the more conventional manner by attaching :the same with pitch or some such adhesive to a ready formed block which resemblesthe block 188 and has sockets like those shown in FIG. 7 or by casting the block 188 directly upon the lens blank L as shown in the drawings. This technique is known in the trade and employs the use of low-melting temperature alloys. One of such alloys is known commercially as Cerrolow. In blocking thisway, a new block is formed for each surfacing operation and the sockets 192 (see FIG. 7) that are formed simultaneously as the block is cast are not subjected to appreciable wear since the block is used only once. Each time a blocking operation is required, a newblock is cast upon the lens blank with newly formed sockets 192.

In referring more particularly to the setting up and operation of the machine 22 in the surfacing of a compound or toric curvature upon a work piece such as the lens blank L (FIG. 1), it is pointed out that this invention relates more particularly to the finishing of a lens blank surface by polishing and wherein the lens blank surface has been preformed by previous conventional grinding or generating operations to a true toric surface shape. Such a lens blank (as shown in FIG. 1) embodies the compound surface curvature s having a base meridian and a cylinder meridian which, for purposes of illustration, have been indicated diagrammatically by the respective lines b and c. The base and cylinder meridians are referred to as such in the trade wherein it is generally understood that the axis of the weaker curvature of a toric surface, which is sometimes called the spherical curvature, is the base meridian and the axis of the more severe or stronger curvature is referred to as the cylinder meridian. These axes or meridians b and c are, of course, disposed at right angles to each other and intersect at the center 0 of the lens blank.

In blocking a lens blank such as shown in FIG. 1 to a block 188, it is generally the practice to align the cylinder axis c of the lens blank parallel to a 'line passing centrally through the sockets 192 so that when the blocked lens blank is supported in the fixture 20 with the holding pins 190 of the yoke 176 placed in the sockets 192 of [the block, the cylinder meridian c of the lens blank will be disposed normal to or at right angles to the axis of the opposing arms 175 of the yoke 176 and the base meridian b of the lens blank will be disposed parallel to the axis along the opposing arms 175 of the yoke 176.

It is po'mted out that the usual procedure in making toric lens blanks is to provide the lens blank with a block 188 prior to the initial generating or grinding of the toric surface s thereon and the toric surface s is formed with its base and cylinder meridians in the above-mentioned known relation to the sockets 192 in the block 188. Without being reblocked, the lens blank is then ready for surfacing in accordance with this invention.

In any case, this invention does not relate to the initial generating of the tonic surface s but does relate to the finishing of said surface by a surfacing operation which may be either a line grinding or a polishing operation or both where the latter operation follows the former.

The process of the invention begins with the blocked lens blank L having a ground true toric surface s thereon.

The tool (FIG. 2) which is used in the performance of the surfacing operation is provided, as pointed out above, with a true toric working surface 2 which is of the final curvature desired on the lens blank and which, for all practical purposes, accurately matches the initially ground compound or toric surface curvature s of the lens blank.

As shown more clearly in FIG. 2, the working surface t of the tool 120 has a base meridian of a curvature matching that of the base curvature of the lens blank L and a cylinder meridian of a curvature matching that of the cylinder curvature of the lens blank L. The base and cylinder meridians of the working surface t of the tool 120 are shown, for purposes of illustration, by the respective lines b and c and it will be noted in FIG. 2 that the location of the cylinder meridian c' of the tool surface t is indicated by a notch 196 at the tool edge. Also, the key slot 140 in the tool 120 is located in parallel alignment with the cylinder meridian of the surface t so that when the tool 120 is applied to the tool adaptor 118, its key slot 140, in fitting over the pin 136, will locate the cylinder axis of the tool surface t in a fixed direction parallel to a line through the pins 190 in the yoke 176. This, therefore, aligns the meridians c and c of the lens blank surface s and the tool surface 1 parallel to each other and the lens blank L and tool 120 are retained in this orbitally aligned relation throughout the surfacing operation.

In the event that this parallel relationship of the respective meridians of the lens blank and tool is not precisely achieved in the initial set-up of the fixture 20, the studs 168 are loosened in the collar 166 and the collar 166 is rotatably adjusted as described above to align the axis of the arms of the yoke perpendicular or normal to the meridian c of the tool 120. The studs 168 are then tightened to permanently lock the collar 166 in place.

It is pointed out that placement of the blocked lens blank in the fixture 20 is accomplished simply by lifting the yoke 176 away from the tool 120 an amount sufficient to permit the blocked lens blank to be positioned between the yoke and tool. The sockets 192 in the block 188 are aligned with the pins 190 in the yoke and the yoke is lowered to position the pins 190 in their respective sockets 192 in the block thereby holding the lens blank against the tool. Removal of a finished lens blank is accomplished by again lifting the yoke 176 to release the pins 190 from the sockets 192 whereupon the blocked lens blank is taken out of the fixture from between the yoke and tool.

As it can be seen from the drawings, the entire fixture 20 is rotated during a surfacing operation while the yoke 176 holds the blocked lens fixed against rotation in the fixture 20 and the interfitting relationships of the pin 136 and key slot 140 hold the tool fixed against rotation in the fixture.

In performing a polishing operation with the device of the invention, a relatively thin polishing pad 198 is attached to the surface t of the tool 120 so as to cover the said surface andybe disposed between it and the surface s of the lens blank L to be worked upon. The pad 198 is selected to be of such character as to conform accurately to the shape of the tool surface t and is preferably secured thereon with a pressure-sensitive adhesive or any cement or the like ordinarily used for this purpose. The polishing pad is preferably formed of a material known to the trade as Pellon or any similarly characterized material. A commonly known felt polishing pad may be used or others formed of plastics.

In producing action or relative movement between the lens blank and tool for purposes of polishing, the fixture 20, as a whole, is rotated by the lower spindle 102 while the upper spindle 58 is rotated to orbit the crank pin 186 and produce a first relative lateral movement between the lens blank L and tool 120. The crank pin being orbited about a circular path while the fixture is rotated causes the lens blank to move generally spirally over the surface of the tool 120.

It has been found that for surfacing the average size of lens blank, good polishing action is achieved by offsetting the axis of the upper spindle approximately 7 /2 millimeters from the axis of the tool while providing an offset of the crank pin 186 from the axis of the upper spindle of approximately 2 /2 millimeters giving the crank pin an orbital path of approximately 5 millimeters in diameter. These figures are arbitrary and obviously can be varied considerably. It has also been found that good results of surface quality are obtained by rotating the upper spindle at approximately 60 revolutions per minute while simultaneously rotating the lower spindle 1i) and fixture 20 at approximately 600 revolutions per minute.

It should be clear that ability of the coupler 148 to flex as required permits the upper end of the fixture 20 to freely follow the movement of the crank pin 186 in producing lateral motion between the lens blank L and tool 120. An additional break-up motion is imparted to the lens blank L by oscillating the entire head 26 of the machine 22 sidewise through the use of the abovedescribed linkage which connects the head 26 to the base 24-. In FIG. 4, it can be seen that the link 30 is provided with a lateral extension 200 to which a depending crank arm 202 is pivotally connected at 204. The lower end of the crank arm 202 is similarly piv-otally connected at 206 to a rotatable camming plate 208 which is driven by a motor 210. An adjusting slot 212 in the camming plate 208 permits the connection 206 to be made at a predetermined spaced location from the axis of rotation of the plate 208 so that the extent of sidewise motion, or oscillation of the machine head 26 can be adjusted as desired. That is, the throw resulting from the eccentricity of the connection 206 relative to the axis of the plate 298 operates the crank arm 202 to raise and lower the same with each revolution of the plate 208. This pivots the link 30 in its pivot blocks 32 and 34 thereby carrying the head 26 in an oscillating sidewise or cross-motion as the motor 210 is operated. A cross-motion of approximately 5 millimeters has been found to produce desirable results. Again, it: is pointed out that the free flexing ability of the coupler 148 permits the upper work-supporting portion of the fixture 20 to follow all motions imparted thereto by movement of the head 26 and rotation of the upper spindle 58 while, at the same time, the coupler 148 being immune to tortional or other forces tending to wind or unwind the same, holds the respective base and cylinder meridians of the lens blank L and tool parallel to each other at all times.

It has been found that, for most polishing operations, a downward pressure of the work piece or lens blank L upon the tool surface of approximately 35 lbs/sq. in. produces desirable results and this pressure is applied by controlled adjustment of the spring 86 as described hereinabove. Also, in order to direct said pressure substantially along a line through the center of curvature of the lens blank and which is substantially normal to the average plane of the general curvature of the tool surface at the point of intersection of said line therewith, the upper spindle housing 56 is tilted or inclined as shown in FIG. 5 by adjustment of its supporting bracket 68 upon the arcuately shaped surface 74 of the head 26 as described hereinabove.

Once this adjustment is made, the upper spindle housing is locked in place 'by the nut 71 on the bolt 79'.

In the operation of polishing a lens blank L when the machine 22 is operated as described above with the polishing pad 1% upon the tool surface I, a fluid polishing medium is applied to the pad 198 preferably continuously during the polishing operation so as to come between the lens blank surface and the pad. Any of the well-known and commercially available polishing mediums may be used. The selection of a polishing medium would be made in accordance with the material of the work piece which may be a glass lens blank or, in some cases, a plastic lens blank. Suitable commercially available polishing mediums for both plastics and glass are well known in the trade.

The polishing medium is applied to the tool and lens blank by means of a feed line or tube 216 (see FIG. 4) carried by the head 26 of the machine with its fluidemitting end 218 directed into the fixture 20 toward the working surface of the tool 120. The tube 216 is attached to the upper spindle housing 56 or may be attached to any convenient part of the head 26.

In order not to hinder the sidewise oscillation of the machine head 26, the tube 216 is preferably formed of conventional flexible tubing or hose material and it is directed from the'head 26 to a suitable pump 220 placed in a container 222 which holds a supply of the polishing medium. The container and pump may be placed within the machine base 24 as shown in FIG. 4 or at any location convenient to the machine.

A splash covering 224 is provided around the fixture 20 and is designed to collect used polishing medium and direct the same back to the container 222 for re-circula-- tion. A collecting and return tube 226 (FIG. 3) extends from the covering 224 for this purpose.

A modification of this portion of the invention is shown in FIG. 12 wherein the fixture 20 and its adjacent associated parts are contained within a bowl 228 which carries the fixture 20 and is mounted upon the lower spindle 102 of the machine 22 so as to be rotated thereby. In this aspect of the invention, the liquid polishing medium is placed in the bowl and, by centrifugal forces caused by rotation of the bowl, the medium is urged against its sides. A stationary collector or scraper 230 is mounted adjacent the inner side of the bowl 228 by means of a bracket 232 fixed to the base 24 of the machine and the scraper acts to scoop up or collect the polishing medium at the sides of the bowl causing the same to be effectively thrown outwardly through an outlet tube 234 back onto the fixture 20 and upon the work piece and tool.

From the above, it should be clear that the fixture 20 provides an exceptionally well balanced piece of equipment which may be rotated at high speeds while the respective base and cylinder meridians of the adjoining surfaces of the lens blank and tool are accurately maintained parallel to each other at all times during the operation of the machine. At the same time, the resilient coupler 148 which acts to maintain this aligned relationship of the tool and work piece allows the work piece to move freely relative to the tool in lateral directions for inducing an abrading or polishing action on the Work plece.

It is pointed out that if the machine 22 is to be used to fine grind the surface of the lens blank L rather than to polish said surface, the polishing pad 198 would not be used. That is, the lens blank L would be placed in direct engagement with the tool surface t and a liquid abrasive medium such as one containing emery particles suspended in water or a suitable vehicle would be used to replace the polishing medium. Otherwise, the operation would be performed identically to that described above for polishing. Certain relatively thin coverings of screening material or the like which are conformable accurately to the tool surface 1 may be used to protect the. tool surface if desired during a surfacing operation Where an emery abrasive material is used. Such coverings would simply replace the polishing pad 198 and thus protect the surface t of the tool from wear.

It will be noted that in FIGS. 1-7, the concave or negative side of the lens blank has been shown as being polished or worked upon and the lens block has been shown as being supported by the yoke 176. This arrangement may be reversed as shown in FIG. '8 so that the convex or plus side of a lens blank L can be readily abraded or polished with the apparatus disclosed herein. In so doing, the work-holding member 236 which resembles the tool 120 in practically all respects is used to support the work piece or lens blank L, The member 236 is placed in the fixture 20 in a manner identical to that described above for the tool 120. The lens blank L, however, is blocked upon the work-holding member 236 with a suitable adhesive 238 such as pitch or the like or a low-melting temperature metallic alloy.

The tool 240, in this case, resembles the block 188 in practically all respects and is supported by the yoke 176 in a manner exactly as described with relation to the block 188. The surface of the tool 240 which engages the lens blank L' is provided with a'toric shape matching that of the plus side of the lens blank and may or may not be provided with a polishing pad 242. The polishing pad 242 would be used for a polishing operation and not used for a fine-grinding surfacing operation with loose abrasives such as emery or the like. When using emery or the like, a wire mesh may replace the polishing pad, if desired.

The operation of the apparatus in surfacing the plus or convex sides of lens blanks as shown in FIG. 8 is identical to that used for surfacing the concave sides of lens blanks and, in essence, only involves a reversal of the tool and work-holding means. It is pointed out that the surfacing of a plus or convex side of a lens blank could be achieved without the reversal of .tool and work holder by providing a tool having a concave toric working surface in place of the convex surface I of tool 120.

The novel method of abrading a compound surface on an article which comprises supporting said article and an abrading member in abrading relation with each other, moving said member and said article relative to each other in irregular paths while retaining the major meridians of said member and article in parallel relation with each other and of balancing the effect of centrifugal force on said member and article to obviate vibration and rnis-alignment of said member and article during said abrading operation results from forming the means for retaining the article and abrading member in meridianal alignment with each other of substantially the same geometrical dimension and weight circumferentially about the axis of rotation of said means so that, when rotated, a more uniform balance of said means is maintained.

FIGS. 9, l0 and 11 illustrate further modifications of the invention wherein, in FIG. 9', a bellows 244 is used in the fixture 20' to replace the spring-shaped coupler 148. The fixture 20 is otherwise identical to the abovedescribed fixture 20 and, functionally, the arrangement of FIG. 9 is identical to that of the fixture 20. The bellows 244 may be formed of pressed sheet metal or the like to the configuration shown in FIG. 9 or, for ease and simplicity of construction, it might be fabricated in the manner illustrated in FIG. 10. The structure of FIG. 10 comprises a plurality of flat rings 246 formed as punchings or the like from sheet steel or other suitable metals and spaced from each other by interleaved wire rings 248 which space the flat rings 246 individually from each other. The wire rings 248 are formed in two sizes, one group thereof being of a diameter only slightly less than the outside diameter of the flat rings 246 and the other group being of a diameter slightly greater than the inside diameter of the flat rings. The respective diameters of these wire rings being such as to permit them to lie between the adjacent or facing sides of the flat rings 246 when the rings 246 are stacked coaxially. This bellowstype of structure is fabricated by coaxially stacking first a large diameter wire ring 248, a flat ring 246, a small diameter wire ring 248 and so on. The wire and flat rings are welded or otherwise secured together to complete the formation of the bellows.

An alternate form of bellows-type structure is shown in FIG. 11 wherein the structure is shown as being extended or expanded for purposes of illustration. This construction embodies only a plurality of identically shaped initially flat ring members 250 similar to the members 24-6 in FIG. 10. The flat ring members 250 are preferably formed of sheet steel or the like which may be spring-tempered and are stacked coaxially. Connections therebetween are made with rivets or the like 252 in the manner illustrated. That is, a first ring 250 is secured to a second ring 250 by rivets placed at two diametrically opposed locations thereon and the next ring 250 is secured to the second ring in similar fashion but with the which is disposed at right angles to the diameter along 13 which the first-mentioned connections were made. The connections of each successive ring 250' to its previously connected one are continued to be made alternately along one diameter and then another disposed normal to the previous one.

From the foregoing, it can be seen that simple, efficient and economical means has been provided for accomplishing all of the objects and advantages of the invention as expressed in the appended claims. Nevertheless, it should be understood that various changes in the construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention and the invention is not to be limited to the exact matters shown and described as only preferred matters have been given for purposes of illustration.

Having described my invention, I claim:

1. A device for use in forming a compound curvature on a surface of a work member comprising a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members fixedly for rotation therewith, a resilient coupler encircling said supporting means and first member, said coupler having one of its ends fixed to said base plate for rotation in unison therewith and holding means on the opposite end of said coupler for receiving and supporting the second of said members in adjacent relation with the first of said members and with given meridians of the respective surfaces of said members retained substantially parallel to each other at all times during rotation of said base plate and coupler carried thereby.

2. A device for use in forming a compound curvature on a surface of a work member comprising a tool member having a Working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members fixedly for rotation substantially coaxially therewith, a resilient coupler embodying a plurality of superimposed spaced convolutes encircling said supporting means and first member when placed thereon, said coupler having one of its ends fixed to said base plate for rotation in unison therewith and holding means on the opposite end of said coupler for receiving and supporting the second of said members in adjacent relation with the first of said members and with given meridians of the respective sur faces of said members retained substantially parallel to each other at all times during rotation of said base plate and coupler carried thereby.

3. A device for use in forming a compound curvature on a surface of a work member comprising a tool member having a working surface thereon of the shape desired to be formed on said surface of said Work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members fixedly for rotation substantially coaxially therewith, a coupler having the configuration of an open-ended bellows surrounding said supporting means and first member when placed thereon, said coupler having one of its ends fixed to said base plate for rotation in unison therewith and holding means on the opposite end of said coupler for receiving and supporting the second of said members in adjacent relation with the first of said members and with given meridians of the respective surfaces of said members retained substantially parallel to each other at all times during rotation of said base plate and coupler.

4. A device for use in forming a compound curvature on a surface of a work member comprising a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable support, means on said support adapted to receive and hold a first of said members fixedly and substantially coaxially with the axis of rotation of said support, a cylindrically shaped resilient coupler surrounding said first member normally in substantially coaxially spaced relation therewith when said first member is placed on said means on said support, one end of said coupler being connected to said support for rotation in unison therewith and its opposite end being free to move laterally relative to said support, holding means on said opposite end of said coupler for holding said second member with said surface thereof in adjacent facing relation to said surface of said first member and said holding means further embodying means for retaining given meridians of the respective surfaces of said members substantially parallel to each other at all times during rotation of said support and coupler.

5. A device for use in forming a compound] curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, means on said base plate adapted to receive and support a first of said members, a resilient coupler rotatable with and carried by said base plate for supporting the second of said members with said surface thereof in adjacent relation to the surface of said first member, said coupler embodying a plurality of super-imposed substantially circular convolutes surrounding said first member in spaced relation therewith, said convolutes being constructed and arranged to move relatively freely to different spaced relationships with one another circumferentially thereabout substantially without orbital movement and means on said base plate and coupling means for holding said members with given meridians of their respective surfaces in fixed substantially parallel relation to each other at all times during movement of said convolutes to different spaced relationships.

6. Apparatus for forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members, a resilient coupler rotatable with and carried by said base plate for supporting the second of said members with said surface thereof in adjacent relation to the surface of said first member, said coupler embodying a plurality of superimposed convolutes surrounding said first member in spaced relation therewith, said convolutes being constructed and arranged to move relatively freely to different spaced relationships with one an other circumferentially thereabout substantially without orbital movement, means on said base plate and coupling means for holding said members with given meridians of their respective surfaces in fixed substtantially parallel relation to each other at all times during movement of said convolutes to different spaced relationships, means for rotating said base plate and means functioning simultaneously to move said second member laterally by controlled amounts relative to said first member during rotation of said base plate.

7. A device for use in forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, means on said base plate adapted to receive and support a first of said members substantially coaxially with the axis of rotation of said base plate, a generally cylindrically shaped resilient coupler embodying a plurality of superimposed annular sections integrally related with each other and resiliently adjustable to different spaced relationships about their circumferences while being substantially immune to relative orbital misalignment, said coupler having one end fixed to said base plate in substantially coaxial relation with the axis of rotation of said base plate and having its opposite end free to move generally laterally relative to said base plate, holding means extending across said opposite 1 5 end of said coupler for receiving and supporting the second of said members with said surface thereof adjacent to and facing said surface of said first member and said holding means having provision thereon for retaining given meridians of said surfaces of said first and second members substantially parallel to each other at all times.

8. A device for use in forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said Work member, a rotatable base plate, means on said base plate adapted to receive and support a first of said members substantially coaxially with the axis of rotation of said base plate, an upstanding spring-shaped coupler embodying a plurality of superimposed convolutes surrounding said supporting means for said first member in spaced substantially coaxial relation therewith, the lowermost of said convolutes being fixed to said base plate to render said coupler rotatable in unison therewith, a yoke-like member fixed to the uppermost of said convolutes and arranged to extend substantially diametrically thereacross, means on said yoke-like member for holding the second of said members with said surface thereof in adjacent facing relation to said surface of said first member when said first member is supported on said means adapted to receive the same and further means on said yoke-like member for retaining given meridians of said respective surfaces of said members substantially parallel to each other at all times.

9. Apparatus for forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members, an upstanding spring-shaped resilient coupler embodying a plurality of superimposed spaced convolutes encircling said supporting means and first member when said first member is placed on said supporting means, the lowermost of said convolutes being fixed to said base plate to render said coupler rotatable in unison therewith, a yoke arranged upon the uppermost of said convolutes so as to extend substantially diametrically thereacross, means on said yoke for holding the second of said members with said surface thereof in adjacent facing relation to said surface of said first member, further means on said yoke for retaining given meridians of said respective surfaces of said members substantially parallel to each other at all times, means for rotating said base plate and means functioning simultaneously to move said second member laterally by controlled amounts relative to said first member during rotation of said base plate.

10. Apparatus for forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, supporting means on said base plate adapted to receive and support a first of said members, an upstanding bellows structure encircling said supporting means and first member when said first member is placed on said supporting means, the lowermost end of said bellows structure being secured to said base plate to render said bellows structure rotatable is unison therewith, a yoke arranged upon the uppermost end of said bellows structure so as to extend substantially diametrically thereacross, means on said yoke for holding the second of said members with said surface thereof in adjacent facing relation to said surface of said first member, further means on said yoke for retaining given meridians of said respective surfaces of said members substantially parallel to each other, means for rotating said base plate and means functioning simultaneously to move said second member laterally by controlled amounts relative to said first member during rotation of said base plate.

11. A device for use in forming a compound curvature on a surface of a work member comprising the combination of a tool member having a working surface thereon of the shape desired to be formed on said surface of said work member, a rotatable base plate, means on said base plate adapted to receive and support a first of said members substantially coaxially with the axis of rotation of said base plate, an upstanding bellows surrounding said supporting means for said first member in spaced substantially coaxial relation therewith, the lower- 'most end of said bellows being fixed to said base plate to render said coupler rotatable in unison therewith, a yoke-like member fixed to the uppermost end of said bellows and arranged to extend substantially diametrically thereacross, means on said yoke-like member for holding the second of said members with said surface thereof in adjacent facing relation to said surface of said first member when said first member is supported on said means adapted to receive the same and further means on said yoke-like member for retaining given meridians of said respective surfaces of said members substantially parallel to each other at all times.

12. Surfacing apparatus for forming a compound curvature on a surface of a work member with a tool member having a working surface thereon of substantially the shape desired to be formed on said work member comprising the combination of a base, a fixture rotatably supported on said base carrying said work and tool members, said fixture embodying a support, means for holding a first of said members rigidly upon said support so as to rotate in unison therewith, a resilient coupler encircling said first member and having one end attached to said support, holding means on the opposite end of said coupler for holding the second of said members with said surface thereof in adjacent relation with said surface of said first member and with given meridians of the respective surfaces retained substantially parallel to each other, means for rotating said fixture and actuating means arranged to engage said holding means on said resilient coupler for moving said second member laterally relative to said first member simultaneously during rotation of said fixture.

13. Surfacing apparatus for forming a compound curvature on a surface of a work member with a tool member having a working surface thereon of substantially the shape desired to be formed on said work member comprising the combination of a base, a fixture rotatably supported on said base carrying said work and tool members, said fixture embodying a base plate, means for supporting a first of said members rigidly upon said 7 base plate so as to rotate in unison therewith, a resilient coupler encircling said first member and having one end attached to said base plate, holding means on the opposite end of said coupler for holding the second of said members with said surface thereof in adjacent relation with said surface of said first member and with given meridians of the respective surfaces, of said members retained substantially parallel to each other, means for rotating said fixture, means operable eccentrically to the axis of rotation of said fixture adapted to engage said holding means on said coupler and operable to move said holding means and second member laterally relative to said first member simultaneously during rotation of said fixture, means for actuating said eccentric means, means for applying pressure upon one of said members in a direction generally toward the other of said members and means for directing a surfacing medium upon at least one of said surfaces of said members.

14. Surfacing apparatus for forming a compound curvature on a surface of a work member with a tool member having a working surface thereon of substantially the shape desired to be formed on said work member comprising the combination of a base, a fixture rotatably supported on said base carrying said work and tool members, said fixture embodying a base plate, means for supporting a first of said members rigidly upon said base plate so as to rotate in unison therewith, a resilient upstanding coupler embodying a plurality of superimposed integrally related spaced convolutes encircling said first member and having one end thereof attached to said base plate, said convolutes being relatively freely movable to different spaced relationships with each other circumferentially thereabout, holding means on the opposite end of said coupler for holding the second of said members with said surface thereof in adjacent relation with said surface of said first member and with given meridians of the respective surfaces retained substantially parallel to each other, means for rotating said fixture and actuating means arranged to engage said holding means on said resilient coupler for moving said second member laterally relative to said first member simultaneously during rotation of said fixture.

15. Surfacing apparatus for forming a compound curvature on a surface of a work member with a tool member having a working surface thereon of substantially the shape desired to be formed on said work member comprising the combination of a base, a fixture rotatably supported on said base carrying said work and tool members, said fixture embodying a base plate, means for supporting a first of said members rigidly upon said base plate so as to rotate in unison therewith, a resilient bellows encircling said first member and having one end attached to said base plate, holding means on the opposite end of said bellows for holding the second of said members with said surface thereof in adjacent relation with said surface of said first member and with given meridians of the respective surfaces retained substantially 18 parallel to each other, means for rotating said fixture and actuating means arranged to engage said holding means on said resilient bellows for moving said second member laterally relative to said first member simultaneously during rotation of said fixture.

16. A device for use in forming a compound curvature on a surface of a work member comprising the combination of a tool member having a Working surface thereon of the shape desired to be formed on said surface of said WOIk member, a rotatable base, means on said base adapted to receive and support a first of said members substantially coaxially with the axis of rotation of said base, resilient coupler embodying a plurality of superimposed annular sections so joined With each other as to be resiliently adjustable to different spaced relationships about their circumferences while being substantially immune to relative orbital misalignment, said coupler having one end fixed to said base in substantially coaxial relation with the axis of rotation of said base and having its opposite end free to move generally laterally relative to said base, holding means extending across said opposite end of said coupler for receiving and supporting the second of said members with said surface thereof adjacent to and facing said surface of said first member and said holding means having provision thereon for retaining given meridians of said surfaces of said first and second members substantially parallel to each other at all times.

References ited in the file of this patent UNITED STATES PATENTS 1,135,936 Edmondson Apr. 1 3, 1915 1,217,090 Growlland Feb. 20, 1917 1,287,479 Simpson Dec. 10, 1918

Claims

1. A DEVICE FOR USE IN FORMING A COMPOUND CURVATURE ON A SURFACE OF A WORK MEMBER COMPRISING A TOOL MEMBER HAVING A WORKING SURFACE THEREON OF THE SHAPE DESIRED TO BE FORMED ON SAID SURFACE OF SAID WORK MEMBER, A ROTATABLE BASE PLATE, SUPPORTING MEANS ON SAID BASE PLATE ADAPTED TO RECEIVE AND SUPPORT A FIRST OF SAID MEMBERS FIXEDLY FOR ROTATION THEREWITH, A RESILIENT COUPLER ENCIRCLING SAID SUPPORTING MEANS AND FIRST MEMBER, SAID COUPLER HAVING ONE OF ITS ENDS FIXED TO SAID BASE PLATE FOR ROTATION IN UNISION THEREWITH AND HOLDING MEANS ON THE OPPOSITE END OF SAID COUPLER FOR RECEIVING AND SUPPORTING THE SECOND OF SAID MEMBERS IN ADJACENT RELATION WITH THE FIRST OF SAID MEMBERS AND WITH GIVEN MERIDIANS OF THE RESPECTIVE SURFACES OF SAID MEMBERS RETAINED SUBSTANTIALLY PARALLEL TO EACH OTHER AT ALL TIMES DURING ROTATION OF SAID BASE PLATE AND COUPLER CARRIED THEREBY.