US3673738A

US3673738A - Edge control device for grinding machine

Info

Publication number: US3673738A
Application number: US125175A
Authority: US
Inventors: Theodore J Stern
Original assignee: AIT IND Inc
Current assignee: AIT INDUSTRIES Inc; AIT IND Inc
Priority date: 1971-03-17
Filing date: 1971-03-17
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: CA922111A

Abstract

The edge control device includes an arm having an extension engageable with a face of an object as the edge of the rotatably supported object is being beveled in the V-groove of a grinding wheel, the extension serving to deflect the lens toward one side of the groove. The arm is linearly adjustable by means of its attachment to a rack mounted for linear movement on a support and driven by a pinion.

Description

United States Patent Stern 1451 July 4, 1972 [54] EDGE CONTROL DEVICE FOR GRINDING MACHINE [72] lnventor: Theodore J. Stern, Skokie, Ill. [73] Assignee: A.].T. Industries, Inc., Skokie, [IL

[22] Filed: March 17, 1971 [211 Appl. No.: 125,175

521 u.s.c1 ..51/93,51/95w11,51/101 LG, 5l/l06 LG 51 1111.01 ..B24b17/04 5111 Field nisearch ..51/93,95 WH, 101 R, 101 LG, 51/102,104,105 R, 105 LG, 106 R, 106 LG l56| References Cited UNITED STATES PATENTS 2,329,713 9/1943 Goddu ..51/101 LG Lannom ..51/101 LG Wrigglesworth ..Sl/lOl LG Primary Examiner-Donald G. Kelly Attorney-Gary, Parker, .Iuettner, Pigott & Cullinan [57] ABSTRACT The edge control device includes an arm having an extension engageable with a face of an object as the edge of the rotatably supported object is being beveled in the V-groove of a grinding whccL'the extension serving to deflect the lens toward one side of the groove. The arm is linearly adjustable by means of its attachment to a rack mounted for linear movement on a support and driven by a pinion.

9 Claims, 6 Drawing Figures EDGE CONTROL DEVICE FOR GRINDING MACHINE BACKGROUND OF THE INVENTION This invention relates to apparatus for grinding articles to a predetermined outline or edge configuration, and more particularly to a device for controlling the bevel configuration in connection with a grinder employing a V-grooved wheel.

The present invention is particularly adapted, but not necessarily limited, to be used in connection with an apparatus for grinding the periphery of eyeglass lenses. One such apparatus ,is shown in U.S. Pat. No. 3,332,172 to Albert Stern, which patent is incorporated herein by reference. In the apparatus therein described, a lens is carried in a rotary work holder driven by a motor such that the edge of the lens may engage a grinding wheel driven by another motor. The rotary work holder is mounted on a carriage for movement toward and away from the grinding wheel, as well as in a direction parallel to the axis of the grinding wheel. The rotating lens is first brought against a cylindrical roughing wheel to rough grind the outer periphery of the lens to the desired shape. The lens is then shifted into engagement with the V-shaped' groove of a grinding wheel to form a projecting bevel on its periphery. During the beveling operation, the work holder is rendered free to travel from side to side, in order that the edgeof the lens will be automatically centered in the groove of the grinding wheel. Inasmuch as the lens becomes centered in the groove, the apex of the bevel formed by the grinding operation will be located about midway from the front and back surfaces of the lens, and the bevel thus formed will be substantially symmetrical with equal width faces.

The purpose of forming a bevel on the edge of the lens is to enable or facilitate mounting of the lens in a frame. In the case of a thick lens, perhaps in the order of 3 mm. or greater, a symmetrical bevel cannot be used because the bevel noticably extends inward from the edge of the frame, thereby rendering the final product objectionable from a cosmetic or appearance viewpoint. As a consequence, special measures must be taken to form unequal bevel surfaces at the edge of the lens, such that the bevel at the front of the lens is hidden by the frame, and many efforts have been expended to this end.

In many prior art beveling machines, the grinding wheel is set at an angle relative to the lens such that the V-groove will have an effective curvature lying in the same direction as the curvature of the lens itself, so that the lens will be accurately beveled. Examples of apparatus of this type may be found in the following U.S. Pat. Nos. 250,691; 1,269,680; 3,315,415; and 3,353,303. A more simple approach, however, is realized if a bevel control can be incorporated into an apparatus wherein the wheel and the work are disposed in a substantially common plane. In connection with the latter type of ap- I paratus, it is known to employ a mechanism to deflect the lens to one side of the groove. Examples of such devices may be found in the following patents: U.S. Pat. No. 2,329,713 and British Pat. No. 1,218,126. In U.S. Pat. No. 2,329,713, the device employed is a tool having point contact with a side of the lens, with means to adjust the height of the tool and to move the tool from side to side along a shaft extending parallel to the axis of the grinding wheel. The British Pat. No. l,2l8,l26 primarily discloses an arm extendable along one side of the V-groove by means of a cam follower. The side to side adjustment is also controlled by a shafi extending to one side of the wheel.

The foregoing control mechanisms suffer from the common disadvantage of being rather complex in nature and requiring adjustment of moving parts to accommodate various size lenses and edge configurations. Moreover, the location of the adjustment knob to one side of the device may be considered impractical if the operator wishes to refer to indexes on the adjusting knob and also observe the progress of the beveling operation.

Accordingly, an object of this invention is to provide a device for adjustably limiting the extent of grinding on one side of a disk-shaped article.

Another object of this invention is to provide a lens bevel control mechanism that is compact in nature, easily adaptable to a wide variety of objects under various conditions and is easily adjustable.

A further object is the provision of a bevel control device that does not require modification of a normal grinding machine and does not mar the lens.

The above and other objects will become apparent from the following description and appended claims, taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a perspective view of my novel bevel control device;

FIG. 2 is a highly schematic elevational view showing a lens held for engagement with the V-groove of a grinding wheel;

FIG. 3 is a schematic side view of a portion of the arrangement shown in FIG. 2, showing the relationship between a portion of my novel device and the grinding wheel and the lens;

FIG. 4 is an elevational isolated view of one part of the device shown in FIG. 1;

FIG. 5 is an elevational isolated view of another part of the device shown in FIG. 1; and

FIG. 6 is a fragmentary plan view of the support for the device shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

The preferred embodiment of my invention is shown in FIGS. l5 of the accompanying drawings, reference being first made to FIGS. 2 and 3. A grinding wheel 10 is secured on a shaft 12 adapted to be driven at high speeds by a motor 14. The grinding wheel 10 has a cylindrical grinding surface 15 with a V-shaped groove 16 therein, which serves to form a projecting bevel on a work object in a manner well known to those skilled in the art.

A rotary work holder for holding a lens 18 is mounted adjacent to the grinding wheel 10 along an axis of rotation substantially parallel to that of the grinding wheel. The rotary work holder comprises a pair of axially aligned

shafts

20 and 22 having respective

opposed heads

24 and 26 that grip against the center of opposite faces of the lens 18, in order to hold the lens in proper position for grinding. Means are also provided to rotate the work holder and to move the holder toward and away from the wheel, as well as to move the holder axially, as illustrated by the arrows in FIG. 2. For example, the work holder may be rotatably mounted in a carriage that is movable in the directions indicated, and a motor may be located on the carriage to drive the work holder. A cam may also be connected to the work holder to allow the grinding of various forms of lenses. The details of the carriage and other associated parts are conventional and are described in the aforementioned Stem U.S. Pat. No. 3,332,172.

From FIG. 2, it may be seen that the grinding wheel 10 an the lens 18 are located in a substantially common plane. In operation, the edge of the rotating lens 18 is urged into the V- shaped groove 16, while the work holder is allowed to travel freely from side to side. Because the lens is allowed to travel laterally, within the groove without restriction, the lens will tend to become centered in the groove, and the projecting bevel formed will have an apex located about midway between the faces of the lens. With thicker lenses, however, it is cosmetically desirable to provide a bevel having a shorter width face 28 adjacent the front side of the lens than the face 30 adjacent the rear side, in order that the bevel will not be visible from the front when the lens is mounted in a frame.

In order to prevent the lens from centering itself in the groove, means are provided to urge or deflect the lens toward one side of the groove, such means taking the form of a bracket arm 32 on which a lateral extension 34 is secured, the free edge of said lateral extension being engageable with one face of the lens 18.

As best shown in FIGS. 1, 2 and 3, the bracket arm 32 is located adjacent to one side of the grinding wheel and extends radially outward and beyond the cylindrical face of said wheel. The end of the bracket arm adjacent the wheel has an upper curved surface 36 upon which the extension 34 is secured to extend over the cylindrical surface of the wheel. It may be seen that the extension 34 is curved to correspond to, and closely overlie the cylindrical surface of the grinding wheel. The extension is also of sufiicient width to overlie the V-groove 16 of the grinding wheel when the bracket arm 32 is moved laterally'toward the wheel. The extension 34 therefore takes the form of a segment of a cylinder having a curved edge 38 that is engageable with one face of the lens. Preferably, the

. extension is formed of a thin strip of a flexible material that is 'softer than or nonabrasive with respect to the work object, in

order to prevent damage to the object. In the case of lenses, the extension is preferably composed of nylon or a similar plastic material and may be provided in the form of a flat strip that assumes the shape of the curved surface 36 of the bracket arm. The strip is mounted on the arm by a plurality of screws 40 through aligned apertures at one side of the extension.

An important feature of my invention is that the extension 34 is elongated to a dimension which normally exceeds the largest diameter of the object on which the bevel is formed, and the extension is curved along its length. These features have been found to facilitate the beveling of lenses of a wide variety of sizes, shapes and thicknesses without resorting to extensive adjustments of the grinding machine or edge deflecting device. i

As shown in FIGS. 1 4 and 5, means are provided for laterally adjusting the bracket arm 32 along a line substantially parallel to the axis of the grinding wheel. The end of the bracket arm 32 which extends beyond the periphery of the grinding wheel is secured to a plate 36 having a pair of vertically elongated slots 40 and 42 near the top thereof (FIG. 5). The plate 36 also includes a head member 44 having a horizontally elongated slot 46, which receives a projecting flange of the base 48, as will be hereinafter described. The plate 36, having a large surface area, may also bear against a coplanar wall 58 depending from the base 48.

As best shown in FIG. 1, a rectangular horizontal support or base 48 having a rectangular opening 50 therein is provided around and receives the upper portion of the grinding wheel 10, as well as the bracket arm 32 with its extension arm 34. At one end of the base 48 opposite to the cylindrical surface 15 of the wheel, the plate 36 of the bracket arm is secured by screws through its slots 40 and 42 into respective threaded openings 52 and 54 of a rack 56 through an opening in a wall 58 depending from the end of the base 48. In order to prevent excessive vertical movements of the bracket arm 32 relative to the base 48, a tap screw or adjustable stop 60 is provided through an arm 62 extending between the bracket arm and the head member 46, said tap screw being engageable with a flange 64 (FIG. 6) projecting from the base 48.

The rack 56 comprises an elongated bar 66 having an upstanding head 68 in which the threaded openings 52 and 54 are located. The lower side of one end of the bar 66 has a plurality of teeth 70 arranged in a common plane and adapted to engage the teeth of a pinion 72 in a driving relationship.

Means are provided for guiding the rack 56 laterally in a direction parallel to the axis of the grinding wheel 10. For this purpose, the head portion 68 of the rack is provided with a transverse or axial bore for sliding reception of a shaft 74 having its ends secured between spaced

lugs

76 and 78, said lugs being rigidly connected by a bar 80 (FIG. 4). In FIG. 1, it may also be seen that the spaced upper surfaces of the bar 66 on opposite sides of the head portion 68 are engageable or slidable along the coplanar flat bottom surfaces of the

lugs

76 and 78 to prevent tilting of the rack 56. The

lugs

76 and 78 are of course spaced sufficiently from one another to allow lateral movement of the head portion 68 therebetween. The rear vertical side of the rack 66 is also slidable along the wall 58 for additional support.

The

lugs

76 and 78 are firmly secured by means of bolts 82 and 84 to a top plate 86 through aligned apertures in the base 48. The top plate 86 includes inwardly projecting ears 88 which may include axially projecting adjustable stops 90 for limiting the extreme lateral travel of the head member 44, as well as an axial guide surface 92 for the front surface of .the head member.

From the foregoing, it may be seen that the rack 56 and the bracket arm 32 are mounted for precise reciprocation with respect to the base 48, and therefore the bracket an'n may be laterally positioned without fear of vibration or misalignment. It will also be noted that the arrangementherein utilized affords a highly compact mechanical system that may be conveniently located at the front of the grinding apparatus, with a minimum of interference with other working parts.

Means are provided to adjustably rotate the pinion 72 such that corresponding linear adjustments are made to the position of the bracket arm 32. The pinion is secured to one end of a shaft 94 and a knob 96 is secured to the other end of the shaft, in order that rotation of the knob will cause linear movement of the rack 56. Support means are also provided for supporting the shaft 94 for rotation about an axis extending at substantially right angles from the vertical wall 58 of the base 48. This support means may take many forms, as for example, the end of the shaft may be journaled in the vertical wall 58. In the preferred embodiment, however, the shaft 94 is independently supported by means of a flange bushing 98 journaled on the shaft between the knob 96 and the pinion 72 and having axial flanges of reduced diameter (one of which is shown at 100) projecting on both sides thereof toward the knob and the pinion, respectively. The flange bushing 98 is generally cylindrical in form and is adapted to be mounted within a sleeve (not shown) extending outward from the body of the grinding machine. A radial threaded opening 102 may be provided in the bushing to receive a bolt through the sleeve, in order to secure the bushing to the body of the grinding machine.

Means are provided for accurately indexing the adjustment of the knob 96, and for this purpose, an adjustment ring 104 is direction to move the extension 34 of the bracket arm 32 such that the face of the lens contacts the extension. Adjustment is made such that the edge 38 of the extension overlies a portion of the V-groove 16, in order that the lens will be deflected to one side of the groove. As a result, the bevel fonned on the restricted side of the lens will be 'less wide than the bevel formed on the opposite side. For thin lenses, where a symmetrical bevel is permissible, the arm 32 may be moved away from the grinding wheel 10 such that the extension 34 does not overlie the V-groove. It may be seen that when the extension is in engagement with the lens, depending on the curvature of the lens, there may be more than one point contact between the extension and the lens, thereby providing a balanced transverse support surface. Moreover, the plastic surface of the extension serves to reduce friction and reduces the possibility of scratching the lens.

While I have described and illustrated what I regard to be the preferred embodiment of my invention, it will be appreciated that various changes, rearrangements and modifications may be made therein without departing from the scope of the invention, as defined by the appended claims.

.1 claim:

1. Edge control device for a grinding machine having a driven grinding wheel with a substantially cylindrical grinding surface with a V-shaped groove therein, said machine having means rotatably mounting a disk-shaped object between its opposed faces for movement thereof toward and away from said groove, as well as means to allow movement of said object from side to side in said groove, whereby a projecting bevel is formed around the edge of said object, said device comprising a bracket arm adjacent one side of said grinding wheel and extending at a right angle from the axis of said wheel beyond the outer periphery thereof, an extension from said bracket arm overlying a portion of the cylindrical surface of said wheel and movable over said V-shaped groove, said extension being curved to correspond to said cylindrical grinding surface and being engageable with a face of said object, and means for adjustably moving said bracket arm from side to side to deflect the object to one side of said V-shaped groove.

2. The device according to claim 1 wherein the means for adjustably moving said bracket arm from side to side comprises a support, a rack mounted for linear reciprocation on said support and secured to the free end of said bracket arm, a pinion in operative engagement with said rack, and means for rotating said pinion.

3. The device according to claim 2 wherein the means for rotating said pinion comprises a shaft, one end of said shaft being secured to said pinion, a knob secured to the other end of said shaft, and shaft support means journaled on said shaft between said pinion and said knob.

4.'The device according to claim 1 wherein said extension is composed of non-abrasive material that is softer than the material composing said object.

5. Edge control device for a grinding machine having a driven grinding wheel with a substantially cylindrical grinding surface with a V-shaped groove therein, said machine having means rotatably mounting a disk-shaped object between its opposed faces for movement thereof toward and away from said groove, as well as means to allow movement of said object from side to side in said groove, said device comprising a support surrounding a portion of said grinding wheel, a rack having a plurality of teeth mounted for linear movement on said support in a direction substantially parallel to the axis of said grinding wheel, a bracket arm secured on said rack and extending adjacent one side of said grinding wheel, lateral extension from said bracket arm overlying a portion of the cylindrical surface of said wheel and extendable upon movement of said bracket arm over said V-shaped groove, said extension being curved to correspond to said cylindrical grinding surface and being engageable with one face of said object, a shaft rotatably supported on an axis nonnal to the grinding wheel axis, a pinion secured at one end of said shaft and having teeth engageable with teeth on said rack, and grasping means associated with said shaft for manual rotation thereof.

6. The device according to claim 5 wherein said rack has an upstanding head portion, an aperture through said head portion parallel to the direction of movement of said rack, a guide extending through said aperture beyond both sides of said head portion, and means for supporting the ends of said guide whereby said rack is slidable on said guide.

7. The device according to claim 6 wherein the means for supporting the ends of said guide comprise a pair of spaced lugs secured to said support, an upper surface of said rack on both sides of said head portion being slidable along respective bottom surfaces of said lugs.

8. The device according to claim 5 wherein a stationary shaft support is provided around said shaft between said pinion and said grasping means, and alignable indexing means is provided on said grasping means and said shaft support to enable a predetermined adjustment of said shaft.

9. The device according to claim 5 wherein a vertical stop extends from said bracket arm and abuts a flange extending from said support.

Claims

1. Edge control device for a grinding machine having a driven grinding wheel with a substantially cylindrical grinding surface with a V-shaped groove therein, said machine having means rotatably mounting a disk-shaped object between its opposed faces for movement thereof toward and away from said groove, as well as means to allow movement of said object from side to side in said groove, whereby a projecting bevel is formed around the edge of said object, said device comprising a bracket arm adjacent one side of said grinding wheel and extending at a right angle from the axis of said wheel beyond the outer periphery thereof, an extension from said bracket arm overlying a portion of the cylindrical surface of said wheel and movable over said V-shaped groove, said extension being curved to correspond to said cylindrical grinding surface and being engageable with a face of said object, and means for adjustably moving said bracket arm from side to side to deflect the object to one side of said Vshaped groove.

4. The device according to claim 1 wherein said extension is composed of non-abrasive material that is softer than the material composing said object.

5. Edge control device for a grinding machine having a driven grinding wheel with a substantially cylindrical grinding surface with a V-shaped groove therein, said machine having means rotatably mounting a disk-shaped object between its opposed faces for movement thereof toward and away from said groove, as well as means to allow movement of said object from side to side in said groove, said device comprising a support surrounding a portion of said grinding wheel, a rack having a plurality of teeth mounted for linear movement on said support in a direction substantially parallel to the axis of said grinding wheel, a bracket arm secured on said rack and extending adjacent one side of said grinding wheel, lateral extension from said bracket arm overlying a portion of the cylindrical surface of said wheel and extendable upon movement of said bracket arm over said V-shaped groove, said extension being curved to correspond to said cylindrical grinding surface and being engageable with onE face of said object, a shaft rotatably supported on an axis normal to the grinding wheel axis, a pinion secured at one end of said shaft and having teeth engageable with teeth on said rack, and grasping means associated with said shaft for manual rotation thereof.