Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
  • B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
  • B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
  • B24B9/08—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass
  • B24B9/14—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of glass of optical work, e.g. lenses, prisms

Definitions

• This invention relates to a shaping machine for lenses made of an organic material, in accordance with the preamble of Claim 1.
• lens shaping machines have been commercially available to eyeglasses manufacturers and opticians, for use on both glass and plastics lenses.
• Such prior machines typically in the form of wheel grinding machines., allow batches of identical lenses to be processed for mounting on eyeglasses frames contingent on the market demands, but cannot handle lenses made of certain (clear or colored) organic materials, such as polycarbonate, acrylate, and the like.
• Figure 1 is a general perspective view of a shaping machine according to the invention
• Figure 2 is a central exploded perspective view from above, drawn to an enlarged scale, of upper and lower lens clamping parts and a lens to be cut, the separable suction cup cylinder holder and block for clamping down the template, and an associated feeler operative to follow the template contour for supplying the grinding device with shape information;
• Figure 3 is a central perspective view from below, also scaled up, showing in detail the separable suction cup cylinder holder and block;
• Figure 4 is a scaled down elevation view of the lens shaping machine according to the invention.
• FIG. 5 is a perspective view showing schematically an improved example of a shaping machine according to the invention.
• Figures 1 to 4 illustrate an embodiment of this lens-shaping machine for corrective lenses in organic material, which comprises a supporting base 1 adapted to be laid on a working bench 67 top and being provided with an upright element 2 on which a handwheel 6 is journalled coaxially for manually rotating a lens 34 of an organic material being processed for shape, i.e. milled to the pattern of a selected template 17.
• a cylindrical element 2 attached to the base 1 receives a screw end 3 which is integral with a disk 4 and a round pin 5, coaxial with each other.
• a cylinder 7 has a hollow cylinder interior 8 terminated at the top with a round base 10 which receives the pin 5 whose round top base 10 contains a hollow spherical socket 11 accommodating a ball 12 surmounted by a cylindrical disk 13 placed between the base 9 of the hollow 8 of the cylinder 7 and the base 10 of the pin 5.
• Said cylinder is fast with a coaxial external handwheel 6 enabling rotation of the template 17 for the lens 34 to be ground.
• the template 17 has a center hole 18 and two offset holes 19 for fitting it over the center pin 15 and the offset pins 16 of the cylinder 7.
• a cylindrical block 20 is fitted detachably over the pins 15 and 16 of the cylinder 7 in contact with the template 17 top, using recesses 22 and 23 formed in the block bottom 21 of the same size as the top base 14 of the cylinder and having the same dimensions as said pins 15 and 16 so as
• the perforated template 17 is clamped fixedly between the cylinder 7 and the block 20 coaxial with each other.
• the block 20 is sunk (24) at the top with a vertical wall 26 lying along its diameter 25.
• Said sunk top 24 accommodates a cylinder holder 27 for a suction cup 32 which has its round base 28 slotted (30) along its diameter 29 to receive the vertical wall 26 of the block 20, thereby providing a drive connection which allows the two parts to revolve as one about a common vertical axis Y shared by all the overlaid circular and cylindrical parts, from the element 2 to the suction cup cylinder holder 27.
• the top ⁇ base 31 of the cylinder holder 27 carries a suction cup 32 made of a flexible material with its concave 33 up.
• the (planar or curved) organic lens 34 is secured by hand pressure in the suction cup 32 with its concave, if any, facing up, and the upper lens clamp 36 connected to an arm 38 lying along the horizontal axis X, orthogonal to the axis Y, is brought into close contact therewith.
• Another arm 39 adapted to be set a distance away from the axis X, is pivoted about a fulcrum point F on the upright 37, having a vertical axis Y', and allows the cutter tool 56 to move away from the axis X' through a distance T and track with its cutter 60 the concave curvature 35 of the lens 34 to shape and chamfer it.
• the arm 39 is actually free to move up and down through a distance T defined by the axis X 5 with a parallel straight line Z varying from base 0 (where the axis Z is coincident with the axis X' ) to base 10 (where the axis Z is farthest from the axis X' of the segment T). In fact, where the lens 34 curvature 35 is greatest, the arm 39 must be set a distance away from the axis X' equal to T.
• a control device 40 for setting the chamfer 44 of the lens 34 true is provided on an end B of the arm 39 and extends along a vertical axis Y' ' ' parallel with the axis Y.
• Said device 40 comprises a turning knob 41 having a vertical screw 42 whose tip 43 contacts a curved plate 49 which duplicates the curvature 35 of the lens 34.
• the plate 49 has a topside face 49' with its concave up, and an underside face 49' ' which is flat and can be rotated through an angle ⁇ about its fulcrum point 50 in the 0 degrees to 70 degrees arcuate range.
• the underlying device 45 for setting the lens 34 curvature 35 comprises a turning knob (46) having a
• the screw 47 is moved up or down to rotate the plate 49 about its pivot point 50, according to whether a planar or maximum curvature lens is to be processed.
• the screw 47 shall have to be raised fully up, thereby setting the line Z farthest from the axis X' , whereas to process a planar lens 34 the screw 47 is lowered fully down to bring the line Z to coincide with the axis X' .
• a further device 51 is usually attached to the axis Y' ' along which the grinding device 56 extends, to enable the pattern of the template 17 as picked up by the feeler 54 to be duplicated, magnified or diminished, whereby the lens 34 can be ground accordingly to the same size as or a larger or a smaller size than the template 17, as befits the size of the glasses frame.
• the cutter tool 56 is connected to said feeler 54 through the stand 55, locates on the vertical axis Y' ' , and includes an electric motor 57 connected to the mains over a power supply cable 58, which motor rotates a shaft 59 carrying an exchangeable cutter bit 60 to suit the chamfer 44 to be given the lens 34 in order for it to fit into the lens mounting groove on the glasses frame.
• An electric suction fan 61 provided with a duct 64 positioned near the cutter bit 60, includes an electric motor 62 driving an impeller 63 to suck up cuttings 66 from . the lens 34 and convey them into a respective bin 65.
• this shaping and grinding machine for eyeglasses lenses made of an organic material, this starts with the disk 4 being rotated in a counterclockwise direction to separate the suction cup 32 from the lens clamp 36, thereby making room for passing the lens 34 between the previously described suction cup 32 and lens clamp 36.
• the disk 4 is rotated clockwise to clamp the lens 34 down between the suction cup 32 and the lens clamp 36.
• the feeler 54 is then set against the template 17 to pick up its shape for transfer to the cutter tool 56 whose cutter bit 60 will
• a shaping machine for corrective lenses according to the invention.
• the shaping machine 101 comprises, on a framework 102, a lens plate holder 103 adapted to receive a corrective lens 104 made of an organic material with its concave up,
• the lens plate holder 103 is supported pivotally on the framework 102 for rotation about a vertical axis R-R of revolution.
• it is supported pivotally on a disk 105 which includes a relatively coarse pitch screw 106 having an axis R-R and engaging a nut 107 attached to the framework 102 to drive the plate holder 103 vertically up and down in directions toward and away from a lens clamp 108 carried on the framework in a freely rotatable manner.
• the lens plate holder 103 is adapted to hold, coaxially with the axis R-R and below the lens 104 to be shaped, a template 109 whose outward contour reflects a desired contour shape for the lens being processed.
• the machine 101 further comprises a machining set 110 including a milling head 111 and a cilindrical feeler 112 of predetermined length.
• the milling head 111 includes a high-speed, preferably 27,000 rpm, electric motor 113 and a shank cutter 114 of small diameter arranged in susbstantial alignment to the feeler 112.
• the shank cutter 114 is formed with a groove 115 for cutting a chamfer around the lens edge.
• the machining set 110 is carried on the framework 114 for movement toward and away from the axis R-R of rotation.
• the machining set 110 is carried on a free end 116 of a horizontal arm 117 having the other end 118 supported for a swinging movement about a pin 119 having a swing axis S-S parallel with the axis R-R.
• the arm 117 is free to slide axially along the pin 119 and displaceable along the swing direction S-S under the action of a ramp 120 which extends
• the arm includes a vertically depending termination 121 having a parallel axis with the swing axis and bearing on the ramp 120.
• the slope of the ramp 120 is laid such that it will be travelled uphill when the machining set 110 is moved away from the rotation axis R-R. In this way, the combined weight of the machining set and the arm will urge the machining set constantly toward the rotation axis R-R.
• the termination 121 is a micrometric screw the operation whereof enables the shank cutter, and hence its groove, to be adjusted in height.
• the ramp 120 is mounted on the framework 102 hinge-fashion, about a horizontal hinge axis T-T lying radially to the swing axis S-S, and that a micrometric screw 122 is provided for varying the ramp slope, as denoted by the reference V, to suit the curvature of the lens being shaped.
• the feeler 112 is affixed to a slide 123 which is mounted on the free end 116 of the arm 117 for guided sliding movement along a horizontal direction U-U substantially perpendicular to the arm.
• a micrometric screw 124 is provided for displacing the slide 123 relative to the arm ends.
• the arm includes a step-down micrometric screw 125 having a vertical axis coincident with the swing axis S-S, said screw being adapted to engage a striker 2& associated with the framework 102 at that axis, specifically on top of the pin 119.
• the arm With the step-down micrometric screw 125 engaged with the striker, the arm is held at a fixed vertical height with the termination raised off the ramp.
• the ramp 20 is formed at its high end with a recess 127 for receiving and holding the termination firmly therein.
• a handgrip 128 is provided for moving the arm toward and away from the position where the termination engages in the recess.
• a handwheel 129 is provided to control the up/down movement of the disk 105.
• Another handwheel 130 is provided for rotating the lens plate holder 103.
• a spring 131 is advantageously stretched
• the machine 101 is completed by a clear semicylindrical guard 132 carried on the milling head in a shiftable manner between a position where it encircles the shank cutter and a position where it is tucked away, and by a suction pipe 133 which has a suction mouth 134 facing the shank cutter to draw away cuttings of organic material being produced by the milling process.
• a corrective lens is shaped by milling with the shank cutter, which is fast with the feeler in turn contacting the template.
• the rotation of the lens holder with the lens being shaped makes the milling process a profiling one, with minimal material removal.
• the precise location of the chamfer in height relative to the lens thickness, the chamfer trueness to the lens curvature, and the desired shape for the lens are respectively obtained by operation of the micrometric screws 121, 122 and 124.
• Planar lenses or templates can be readily provided by holding the arm at a predetermined height level, to be set by means of the micrometric screw 125.
• the major advantage of the shaping machine according to the invention resides in its uniquely high productivity, as ensured by that the outward thicker portion of the lens being shaped is removed as one piece by the shank cutter, the tool bit only reducing to minute cuttings a narrow band around the desired lens profile shape.
• a further important advantage of the machine according to this invention is the high quality of the chamfered edge, which will retain its desired cross-sectional shape even in the presence of deep variations in the lens profile by virtue of the small diameter of the shank cutter.
• the. chamfer will be always properly positioned relative to the lens thickness all around the lens profile, because of the cutter position in height being adjustable to suit the lens curvature. Lens shaping and lens chamfering can be accomplished in a single operation.
• inventive machine allows corrective lenses of different size to be shaped to the pattern of a single template, because of the possibility provided of changing the feeler setting relative to the shank cutter. Another important advantage of the inventive machine is that it allows
• corrective lenses to be shaped to fancy profile patterns, such as may be even characterized by fairly sharp depressions, and this by virtue of the small diameter of the shank cutter.
• This machine has also shown to be a versatile one, by enabling templates to be formed from one template, and lenses shaped using the old lenses for a template. Also, the shape and dimensions of the chamfers, channels and the like, can be simply varied by changing the shank cutter accordingly. In addition, all the organic materials employed for corrective lens making have shown to be faultlessly workable on it.
• the machine has proved to be ergonomically favorable and could, where necessary, be power actuated for automated operation.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
• Milling Processes (AREA)
• Eyeglasses (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=11365580

Family Applications (1)

Country Status (6)

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• 1993
  • 1993-07-27 IT ITMI930628 patent/IT230613Y1/it active IP Right Grant
• 1994
  • 1994-07-26 EP EP94924805A patent/EP0713439B1/de not_active Expired - Lifetime
  • 1994-07-26 WO PCT/EP1994/002468 patent/WO1995003918A1/en active IP Right Grant
  • 1994-07-26 AU AU74958/94A patent/AU7495894A/en not_active Abandoned
  • 1994-07-26 ES ES94924805T patent/ES2101561T3/es not_active Expired - Lifetime
  • 1994-07-26 DE DE69402873T patent/DE69402873D1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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