Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
  • H02K49/10—Dynamo-electric clutches; Dynamo-electric brakes of the permanent-magnet type
  • H02K49/104—Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element
  • H02K49/106—Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element with a radial air gap
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/70—Stationary or movable members for carrying working-spindles for attachment of tools or work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q5/00—Driving or feeding mechanisms; Control arrangements therefor
  • B23Q5/02—Driving main working members
  • B23Q5/04—Driving main working members rotary shafts, e.g. working-spindles
  • B23Q5/10—Driving main working members rotary shafts, e.g. working-spindles driven essentially by electrical means
• • 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
  • B24B47/00—Drives or gearings; Equipment therefor
  • B24B47/10—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces
  • B24B47/12—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces by mechanical gearing or electric power

Definitions

• This invention relates to an improved machine for diamond turning and polishing contact lenses and the like.
• the object of the invention is to provide a machine for diamond turning and polishing contact lenses or the like which eliminates the drawbacks above referred to and enables high quality accurate lenses to be obtained and the risk of breakage both of lenses and tools avoided, or substantially so.
• a machine for diamond turning and polishing contact lenses or the like wherein the drive from a prime mover, e.g. an electric motor, to means for rotatably supporting a uorkpiece, is effected through the intermediar of a magnetic coupling that avoids transmission of vibration of said prime mover, or mechanism assocated therewith, to said r ⁇ tatable support means.
• a prime mover e.g. an electric motor
• breakage is avoided by a predetermined torque between the two magnets of the magnetic coupling resulting in the means rotatably supporting the workpiece being stopped in the event of excessive pressure being exerted between the workpiece and a tool acting thereon.
• An advantage also resulting from this invention is that mechanical noise is significantly reduced during operation ⁇ f the machine.
• Figure 2 is a longitudinal section taken through the casing of the apparatus.
• the apparatus comprises a shaft 1 driven in both clockwise and anti-clockwise directions by a printed armature motor 2, the shaft 1 transmitting a drive to the machine spindle 7 by way of a magnetic coupling comprising inner and outer ceramic magnets 6 and 3 respectively supported by metal adaptors 5 and 4.
• the magnet 6, by way of its adaptor 5, is fixed to the drive shaft 1 and the magnet 3, by way of its adaptor 4 is fixed to the spindle 7.
• the magnets 3 and 6 are aligned in order that the magnetic force between the two will drive the spindle 7 without physical contact between the spindle 7 and the motor 2 when the latter is activated.
• the machine spindle 7 is hollow and is mounted to rotate in bearings in a casing 8, said bearings comprising self-aligning angular contact ball races 9 and 10 having spacers 11 and 12 interposed therebetween, and a self-aligning angular contact ball race 13 mounted in a sleeve 14, a spacer 15 being interposed between this latter bearing and the bearing 10.
• This assembly of bearings which ensures stability of rotation of the spindle 7, is held in position in the casing 8 by retaining rings 16 and 17 at the ends of the casing 8.
• the casing 8 is mounted on a metal bed (not shown) ensuring that the machine is very stable.
• a work piece e.g. a contact lens
• a tapered adaptor 7a fitted to or formed integral with, the front end of the machine shaft or spindle 7.
• the machine spindle is supported by a minimum total of two bearings. At least one ball race is provided at the end of the spindle adjacent the workpiece-receiving adaptor and at the end of the spindle adjacent the magnetic coupling and drive shaft. These bearings may be separated by a spacer or suitable spacing means. Suitable bearings in all embodiments include angular contact ball races which may additionally be self-aligning.
• the provision of the magnetic drive coupling above described also overcomes the problem of tool breakage that has previously been experienced with known machines because a predetermined braking torque between the two magnets 3 and 6 ensures that the spindle 7 will immediately stop if the diamond turning tool is plunged into the workpiece and excessive pressure created between the latter and the tool. With a conventional belt drive mechanism a diamond turning tool would be damaged because of the aitg ⁇ ing inertia in the spindle 7.
• the electric motor 2 is a D.C. motor as this has low vibration.
• this invention is primarily concerned with the diamond turning and polishing of contact lenses, it is to be appreciated that it can be adapted to be used for analogous purposes, such as for the diamond turning and polishing of lenses or the like for scientific apparatus such as those for cameras; optical apparatus, microscopes and the working of any non-ferrous or precious metal or plastic component parts.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Power Engineering (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10516445

Family Applications (1)

Country Status (6)

Cited By (3)

Citations (6)

• 1981
  • 1981-08-20 WO PCT/GB1981/000166 patent/WO1982001149A1/en not_active Application Discontinuation
  • 1981-08-20 EP EP81902285A patent/EP0069735A1/en not_active Withdrawn
  • 1981-08-20 JP JP56502759A patent/JPS57501616A/ja active Pending
  • 1981-08-26 CA CA000384636A patent/CA1176678A/en not_active Expired
  • 1981-08-28 BE BE0/205815A patent/BE890149A/fr not_active IP Right Cessation
  • 1981-09-17 IT IT68215/81A patent/IT1144869B/it active

Patent Citations (6)

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