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
  • B24B5/00—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor
  • B24B5/36—Single-purpose machines or devices
  • B24B5/37—Single-purpose machines or devices for grinding rolls, e.g. barrel-shaped rolls
• • 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
  • B24B5/00—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor
  • B24B5/50—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground, e.g. strings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
  • B24D5/10—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor with cooling provisions, e.g. with radial slots

Definitions

• the present invention relates to a grinding wheel device for machining, including surfacing, of elastic and felt-elastic materials.
• Two machining techniques are known from grinding wheels: the so-called “sweeping” technique according to which a grinding wheel having a width smaller than the length of the workpiece, “sweeps” said workpiece by moving in front of it at a distance desired, and the technique called “plunging” according to which the workpiece is attacked by a grinding wheel whose width is at least equal to the length of this piece so as to perform the machining thereof without having to move it laterally.
• the "sweeping” technique has the double advantage over the “plunging” technique, allowing the use of smaller grinding wheels and ensuring the machining of parts made of elastic or semi-elastic materials.
• the relative movement between the grinding wheel and the workpiece is radial with respect to the latter, and if the workpiece is made of somewhat elastic material, there is necessarily a crushing of the surface which prevents non-controlling not only the correct dimensioning of the part, but also its final surface condition.
• the pressure exerted by the grinding wheel always causes, more or less, a deflection of the part during machining and the result of this deflection is to give the finished part a rounded shape. more or less important undesirable.
• the object of the present invention is to propose a wheel device for machining, including surfacing, parts made of elastic or semi-elastic materials, making it possible to use the "plunge” technique while retaining the advantages of the technique. "sweeping" with regard to compliance with the dimensions and the final surface condition.
• the grinding wheel acting "plunging" is provided with means capable of ensuring for a certain time, at the end of the machining operation, the immobilization of the part being machined in such a way that its axis of rotation is , at the right of its support points, at an equal distance, relative to the axis of rotation of the grinding wheel, to the sum of the theoretical radius of the desired part and the radius of the grinding wheel
• This arrangement makes it possible to obtain, after roughing, a part with precise dimensions, therefore with a precise shape, and with a surface finish as fine as desired, even if these are parts made of elastic materials.
• the device according to the invention is provided with means allowing, during the roughing period, a slight floating of the axis of rotation of the part during machining.
• two open supports are provided, each of which is constituted by a part comprising two surfaces arranged at right angles to one another, on which the axis of the part being machined is likely to be supported along two of its generators, on lines located less than 180o from each other with respect to said axis of the part, means being provided to prevent this axis from escaping these supports at course of the fluctuations experienced by said part.
• the control in rotation of the part during machining is obtained by a flexible control, which allows without disadvantage, during machining, a bending of the axis carrying said part .
• an adjustable support is provided which can exert on the roller during machining, a controlled elastic thrust s exerting against the pressure exerted by the grinding wheel.
• Another means of reducing the pressure exerted by the grinding wheel on the workpiece consists, according to the invention, in using a grinding wheel having, over its entire periphery, recesses arranged so as to produce with the active surface portions , an alternation such that the active surface / recesses ratio is constant on any plane perpendicular to a generatrix of the grinding wheel and passing through any point of this generatrix.
• the leading edges of the recesses existing on the surface of the grinding wheel form, with a generator of said grinding wheel, an angle other than zero, the advantage of such an arrangement being a lesser wear of the grinding wheel at the same time as a less brutal attack on the part to be removed.
• the recesses of the grinding wheel are constituted by helical grooves extending over the entire length of the grinding wheel, which allows a technically easier realization and increases the scouring effect of the recesses on the wheel.
• Figure 1 is a front view of a machining device according to the invention.
• Figure 2 is a plan view of Figure 1.
• Figure 3 is a section along III-III of Figure 1.
• Figure 4 shows, on a larger scale, a detail of Figure 3.
• the apparatus comprises a frame 1 carrying a grinding wheel 2 which rotates around an axis 3 secured to the output shaft a motor 4 with two positions, one ensuring only the drive in rotation of the axis and the grinding wheel, and the other simultaneously impulsing them an axial movement back and forth (arrow 38).
• the grinding wheel 2 has a diameter of 15 centimeters and has, over its entire periphery, recesses formed by crossed helical grooves with a depth of 10 millimeters and arranged so that the ratio of active surface / recesses is constant over any plane perpendicular to a generator of the grinding wheel passing through any point of this generator. This ratio is, in this case, of 1, but can vary while being preferably situated between 0.6 and 1.2,
• a mobile assembly 6, consisting of two plates 7 and 8, is capable of sliding on the base of the frame 1 thanks to two rails 5 with crossed rollers cooperating with two grooves provided on the plate 7.
• the plate 7 has an operating stick 31 secured to the movable part of an oleopneumatic device 32 controlled, through a timer 39, by an approach detector 33.
• the plate 8 rotatably mounted on the plate 7 by means of a pivot 9, has an angular locking device which is not shown because it is not part of the invention. It carries, at its upper part, two rails 10 perpendicular to the rails 5, and two supports 11 and, on the side, a plate 29 on which an electric motor 28 is arranged.
• the rails 10 allow a mobile assembly 13 (see FIG. 4) essentially consisting of two slides 14 and 15, to move parallel to the handle 3 of the grinding wheel.
• the slide 14 comprises a sole 16 and a heel 17, the sole 16 carrying on its upper surface, a guide rail 15, and on its lower surface, two grooves 12 corresponding to the two rails 10 of the plate ⁇ ,
• the slider 15 carries, on the first part, a groove corresponding to the guide rail 18 of the slider 14, on the second part, a threaded rod 19 which freely crosses the heel 17 of said slider 14 and is provided with two nuts 20 at its end, and thirdly, an axis 21 on which two double levers 22 freely rotate, each of which carries two free wheels 23.
• a spring 24 is threaded on the threaded rod 19 and is supported, on one side, on the heel 17, and on the other side, on the rear of the slide 15.
• the supports 11 are arranged, in an adjustable manner, on a rail 36 parallel to the rails 10 on which the mobile assembly 13 moves.
• Their head is constituted by an asymmetrical notch constituting an open support for receiving the axis 26 and which is formed by two surfaces arranged at right angles to each other, namely the upper horizontal surface of the support and the side of a vertical projection 39.
• a mobile stop 35 is provided, the role of which will be explained below.
• a roller 25 is shown during machining. It is mounted on an axis 26 placed on the head of the supports 11, the mobile stops 35 being arranged, by means not shown because they are not part of the invention, at a certain distance from the axis 26, and having the effect of preventing it from escaping from the supports 11 while allowing it to float slightly.
• the axis 26 is secured by a fitting device 34, to a flexible control 27 constituted by a spring itself secured to the output shaft of the motor 28 carried by the plate 29 of the plate 8 .
• the hardness of the spring 24 is adjusted as a function of the desired shape of the roller;
• the timer 39 is adjusted according to the time during which the oleo-pneumatic device will be immohô-ised to ensure surfacing;
• the motor 4 is launched in the position which ensures both the rotation of the grinding wheel 2 and its axial movement back and forth, and the motor 28 which controls, the rotation of the roller 25 in the opposite direction to the grinding wheel 2;
• the oil pneumatic device 32 is triggered.
• the latter advances the assembly 6 towards the grinding wheel 2, until the roller 25 comes into contact with the latter,
• the machining begins, each grain of the grinding wheel acting, due to the back and forth movement which it is animated, on an area of the roller 25 and not only on a line, which improves the regularity of the machining.
• the presence of the recesses on the grinding wheel favors the aspiration of shavings and dust, thus ensuring permanent cleaning of the grinding wheel.
• the oleo-pneumatic device stops the assembly 6, thus immobilizing the supports of the roller 25.
• the timer 39 is triggered and the machining continues in this position since the roller continues to rotate, as well as the grinding wheel 2, If we want to give a non-cylindrical shape to the roller 25, we however stop the control of the back-and-forth movement of the grinding wheel 2. But as the machining of the roller 25 continues, its diameter decreases and the pressure of the wheel on it therefore also decreases until it disappears completely. When all radial pressure has disappeared on the roller during machining, surfacing is carried out at the desired dimensions and grain, whatever the elastic characteristics thereof.
• the time during which the workpiece will be left to rotate after reaching the defined position will preferably be between 10 and 30 seconds depending on the desired grain size.
• the timer 39 moves the movable assembly 6 backward.
• the engine 28 is stopped.
• the roller 25 is removed and it is uncoupled from its flexible control.
• the recesses of the grinding wheel 2 could be made other than by crossed helical grooves. They could, for example, be the reverse of the embodiment illustrated by the figures, the grooves becoming the active surface of the grinding wheel and the diamonds becoming recesses which would then be discontinuous.
• the flexible control 27 could obviously be replaced by a flexible cable or even a device with one or more cardan joints.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Grinding Of Cylindrical And Plane Surfaces (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Springs (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9402915

Family Applications (1)

Country Status (9)

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• 1990
  • 1990-12-05 FR FR9015220A patent/FR2670150B1/fr not_active Expired - Fee Related
• 1991
  • 1991-12-05 US US08/070,433 patent/US5443411A/en not_active Expired - Fee Related
  • 1991-12-05 AT AT92901499T patent/ATE108114T1/de not_active IP Right Cessation
  • 1991-12-05 EP EP92901499A patent/EP0560888B1/de not_active Expired - Lifetime
  • 1991-12-05 JP JP4501441A patent/JPH06505924A/ja active Pending
  • 1991-12-05 WO PCT/FR1991/000972 patent/WO1992010331A1/fr active IP Right Grant
  • 1991-12-05 AU AU91030/91A patent/AU9103091A/en not_active Abandoned
  • 1991-12-05 ES ES92901499T patent/ES2059210T3/es not_active Expired - Lifetime
  • 1991-12-05 DE DE69102772T patent/DE69102772T2/de not_active Expired - Fee Related

Non-Patent Citations (1)

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