APPARATUS FOR CUTTING GLASS PLATE

Abstract: An apparatus for cutting a glass plate is provided, wherein a cutter head can be moved relative to a glass plate at high speed and with high precision along a shape to be formed with a cutting line on the glass plate, work efficiency can be improved and products of high quality can be obtained. The apparatus has such an arrangement that: a bridge frame (4) having an X-direction straightly moving means (3) for straightly moving the cutter head (2) in a direction of X-axis is supported by side members (5 and 6) in a manner to be movable in a Y-direction; ball screw nuts (7 and 8) are rotatably mounted and threadably coupled to ball screws (9 and 10) extending in the Y-direction; a Y-direction straightly moving means (11) is provided; another ball screw (12) extending in the X-direction is provided on the bridge frame (4); another ball screw nut (13) is rotatably mounted; and the ball nut (13) is rotated by the X-direction straightly moving means (3) to straightly move the cutter head (2) in the X-direction.

Description: TECHNICAL FIELD The present invention relates to glass plate cutting devices. BACKGROUND ART In a conventional glass plate cutting device, that is, in a breaking line forming device, a threaded shaft is connected to a moving base to which a cutter head is mounted and also connected through a pulley, a belt, etc., to a rotational output shaft of an electric motor, which is rotated and hence the threaded shaft is rotated to move the moving base, for example, in the direction of X. A threaded shaft is connected through a nut to a bed on which a glass plate is placed. The threaded shaft is connected through a pulley, a belt, etc., to the rotational output shaft of an electric motor, which is rotated and hence the threaded shaft is rotated to move the base, for example, in the direction of Y. Thus, a cutter wheel of the cutter head is moved along a cutting or breaking line to be formed on the glass plate. In this conventional apparatus, the relatively long threaded shaft is rotated, so that large bending vibrations occur on the threaded shaft in a dangerous speed region. Thus, it is difficult to rotate the threaded shaft at high speed to move the moving base and bed at high speed to thereby improve the working efficiency. The present invention is made in view of the above problems. It is an object of the present invention to provide a glass plate cutting device which is capable of moving the cutter head at high speed and accurately along a cutting line to be applied on a plate of glass, improving the working efficiency and providing a high quality product. JP-A-3-115,134 discloses a glass-plate cutting machine which has a single ball screw which is rotated to move the bridge frame in the Y direction. JP-U-1-122043 discloses a glass-plate cutting device which has a ball screw a each end of the bridge frame which are rotated by separate stepper motors to move the bridge frame in the Y direction. According to the present invention there is provided a glass plate cutting device comprising: a bridge frame supported at opposite ends thereof so as to be movable in a Y direction; a cutter head supported on the bridge frame; and a pair of ball screws extending in the Y direction; characterised in that the cutting device further comprises: a pair of ball screw nuts each attached rotatably to a respective end of the bridge frame, each nut being screwed on a respective one of the screws, and Y direction linearly moving means for synchronously rotating both the nuts to move the bridge frame in the Y direction. According to the present invention, the Y direction linearly moving means which rotates both the ball screw nuts synchronously to move the bridge frame linearly in the Y direction is provided. Thus, the cutter head is moved at high speed in the Y direction. Since both ends of the bridge frame are moved synchronously, the cutter head is moved accurately in the Y direction. Maintenance and adjustment are made simply in a short time, the working efficiency is improved, and high quality products are obtained. Optionally, according to the present invention, the bridge frame of the glass plate cutting device also includes an X direction linearly moving means for moving a cutter head linearly in the X direction. In this glass plate cutting device, the Y direction linearly moving means rotates both the ball screw nuts synchronously to thereby move the bridge frame in the Y direction while the X direction linearly moving means moves the cutter head in the X direction. The cutter head is moved at high speed in an X-Y plane along the configuration of the glass plate on which a cutting line is formed. Also optionally according to the present invention, this glass plate cutting device further includes a further ball screw extending in the X direction provided on the bridge frame, a further ball screw nut screwed over the further ball screw and attached rotatably to the X direction linearly moving means, whereby the further ball screw is rotated by the X direction linearly moving means to move the cutter head in the X direction. The present invention will be described with respect to preferred exemplary embodiments thereof shown in the drawings. The present invention is not limited to those embodiments. Fig. 1 is a plan view of a preferred embodiment of the present invention. Fig. 2 is a front view of the embodiment of Fig. 1. Fig. 3 is a cross-sectional view of the details of a part of the embodiment of Fig. 1. Fig. 4 is a plan view of another preferred embodiment of the present invention. Fig. 5 is a front view of the embodiment of Fig. 4. EMBODIMENTS In the Figures, the glass plate cutting device 1 of the first embodiment includes a bridge frame 4 at its opposite ends 5 and 6 such that the frame 4 is movable in the Y direction. The bridge frame 4 mounts thereon an X direction linearly moving unit 3 which moves a cutter head 2 linearly in the X direction. Both the ends 5 and 6 of the frame 4 have ball screw nuts 7 and 8, respectively, attached rotatably thereto. Ball screws 9 and 10 extending in the Y direction are screwed in the nuts 7 and 8, respectively. Y direction linearly moving units 11 synchronously rotate the corresponding ball screw nuts 7 and 8 to move the bridge frame 4 linearly in the Y direction. A further ball screw 12 extending in the X direction is provided on the bridge frame 4. A further ball screw nut 13 which is screwed over the ball screw 12 is attached rotatably to the X direction linearly moving unit 3 such that the X direction linearly moving unit 3 rotates the ball screw nut 13 to move the cutter head 2 linearly in the X direction. The cutter head 2 is provided with an air cylinder 22 attached to a bracket 21, and a cutter block 24 with a cutter wheel 23 and attached to a piston rod of the air cylinder 22. By feeding/releasing pressurized air to/from the air cylinder 22, the cutter block 24 is moved up and down such that the cutter wheel 23 is moved toward/away from the glass plate 25. The air pressure in the air cylinder 22 presses the cutter wheel 23 against the glass plate 25 to form a cutting or breaking line C on the glass plate 25. Sliders 31 and 32 are attached to corresponding lower surfaces of the ends 5 and 6 of the bridge frame 4. The slider 31 is fitted slidable in the Y direction on a rail 34 which extends in the Y direction and is attached to a bed 33 on which the glass plate 25 is placed. The slider 32 is similarly fitted slidable in the Y direction on a rail 35 which extends in the Y direction and is attached to the bed 33. Thus, the bridge frame 4 is guidable on the rails 34 and 35 in the Y direction. The ball screws 9 and 10 each are fixed at opposite ends to the bed 33 through supporting members 37. The ball screw nuts 7 and 8 screwed on the ball screws 9 and 10, respectively, have the same structure, so that only the ball screw nut 7 will be described below. The ball screw nut 7 is provided with a nut body 44 provided rotatably through balls 43 within a hollow cylindrical member 42 attached to the bridge frame 4 by bolts 41, and a multiplicity of steel balls 49 disposed successively within a spiral hole 48 communicating with both ends of holes 45 formed in the nut body 44, and formed by a screw groove 46 communicating with both ends of the holes 45, a thread groove 46 in the ball screw 9, and a spiral groove 47 in the inner circumferential surface of the nut body 44. Rotation of the nut body 44 around the ball screw 9 moves in the Y direction the nut body 44 and hence the bridge frame 4 connected through the balls 43 and the cylindrical member 42 to the nut body 44. A toothed pulley 52 is fixed to the nut body 44 by bolts 51. A timing belt 53 extends around on a pulley 52. A toothed pulley 54 is fixed to the nut body (not shown) of the ball screw nut 8. A timing belt 55 extends around on a pulley 54. A toothed pulley 54 is fixed to the nut body (not shown) of the ball screw 8. Toothed pulleys 63 and 64 are fixed to the rotational output shafts of electric motors 61 and 62, respectively, of the Y direction linearly moving units 11 provided in the corresponding ends 5 and 6 of the bridge frame 4 with the timing belts 53 and 55 extending on the pulleys 63 and 64, respectively. Rotation of the shafts of the motors 61 and 62 due to synchronous operation of those motors rotates the nut body 44 and the nut body of the ball screw nut 8 through the pulley 63, timing belt 53 and pulley 52 and through the pulley 64, timing belt 55 and pulley 54, respectively. Thus, both ends 5 and 6 of the bridge frame 4 are moved synchronously in the Y direction. The X direction linearly moving unit 3 is provided with an electric motor 71 attached to a base 72 by bolts 73. A slider 75 is attached by bolts 74 to the base 72 to which a bracket 21 is also attached. The slider 75 is fitted over a rail 76 attached to a side of the bridge frame 4 so as to be movable in the X direction. Thus, the base 72 is movable in the X direction. The ball screw 12 is fixed at opposite ends by support members 81 and 82 to an upper surface of the bridge frame 4. The ball screw nut 13 has the same configuration as the ball screw nuts 7 and 8. The nut body 83 screwed over the ball screw 12 is attached rotatably on the base 72. A timing belt 85 extends around a toothed pulley 84 fixed to the nut body 83 and also around a pulley 86 attached to the output shaft of the motor 71. When the motor 71 is operated and hence its rotational output shaft is rotated, the nut body 83 is rotated through the pulley 86, timing belt 85 and pulley 86. Thus, the base 72 and the cutter head 2 attached to the base 72 are moved in the X direction. The motors 61, 62, 71 and the air pressure cylinder 22 each are connected to a numerical control unit 91 such that their operations are controlled by a program stored beforehand in the control unit 91. The glass plate cutting device 1, thus constructed, operates as follows: The motors 61 and 62 are operated synchronously under the control of the control unit 91 such that the nut bodies of the ball screw nuts 7 and 8 and both ends 5 and 6 of the bridge frame 4 are moved synchronously in the Y direction. Simultaneously, the motor 71 is operated under the control of the control unit 91 to rotate the nut body of the ball screw nut 13 to thereby the base 72 in the X direction. The movement of the bridge frame 4 in the Y direction and the movement of the base 72 in the X direction causes the cutter head 2 to move along a cutting line C to be formed. When the cutter head 2 is moved to a position where the cutting line C is formed, the control unit 91 operates the air cylinder 22 to lower the cutter block 24 to thereby press the cutter wheel 23 against the glass plate 25. This forms the predetermined cutting line C on the glass plate 25 and corresponding to the configuration of the glass plate along which the glass plate is broken. In the cutting device 1, the nut bodies of the ball screw nuts 7, 8 and 13 screwed over the long ball screws 9, 10 and 12 are rotated to move the bridge frame 4 and the base 72 in the X and Y directions without rotating the screws 9, 10 and 12 to thereby move the cutter head 2 to a portion of the glass plate 25 to which the cutting line C is formed. Thus, the nut bodies of the nuts 7, 8 and 13 are easily rotated at high speed without bending vibrations due to high speed rotation of the long ball screws 9, 10 and 12 to thereby move the cutter head 2 at high speed. Since the nut bodies of the screws 7 and 8 are rotated synchronously, the cutter blade 23 is moved accurately. While in the embodiment the cutter head 2 is illustrated as being moved in the X direction, the cutter head 2 may be fixed to the bridge frame 4 to thereby move the glass plate 25 with a similar mechanism in the X direction. While in the cutting device 1 the two synchronously operated electric motors 61 and 62 compose the Y direction linearly moving unit 11, a Y direction linearly moving unit 111 common to both the nuts 7 and 8, as shown in Figs. 4 and 5, may be provided to form a glass plate cutting device 100. The Y direction linearly moving unit 111 of Figs. 4 and 5 is provided with an electric motor 611 attached through a bracket 621 to substantially the center of the bridge frame 4. Toothed pulleys 631 and 641 are fixed to the rotational output shaft of the motor 611. Timing belts 53 and 55 extend around the pulleys 631 and 641, respectively. The motor 611 is also connected to the control unit 91 such that it is controlled by a program stored beforehand in the storage of the control unit 91 in a manner similar to that used in the previous embodiment. When the motor 611 is operated to and its output shaft is rotated in the Y direction linearly moving unit 111, the nut body 44 is rotated through the pulley 631, timing belt 53 and pulley 52 while the body of the nut 8 is rotated through the pulley 641, timing belt 55 and pulley 54. Thus, the ends 5 and 6 of the bridge frame 4 are moved synchronously in the Y direction. As described above, when the synchronous rotation of the bodies of the nuts 7 and 8 is made by the Y direction linearly moving unit 111 common to the nuts 7 and 8, that is, by the single motor 611 as in the present embodiment, strict selection of such electric motor for synchronous purposes, and much maintenance and adjustment of the electric circuit are not required, and maintenance and adjustment are simply made in a short time.

Claims: A glass plate cutting device comprising: a bridge frame (4) supported at opposite ends (5, 6) thereof so as to be movable in a Y direction; a cutter head (2) supported on the bridge frame (4); and a pair of ball screws (9, 10) extending in the Y direction; characterised in that the cutting device further comprises: a pair of ball screw nuts (7, 8) each attached rotatably to a respective end (5, 6) of the bridge frame (4), each of the nuts (7, 8) being screwed on a respective one of the screws (9, 10), and Y direction linearly moving means (11, 111) for synchronously rotating both the nuts (7, 8) to move the bridge frame (4) in the Y direction. A glass plate cutting device according to claim 1, wherein said cutter head (2) is movable in an X direction, and the cutting device further comprises X direction linearly moving means (3) for moving the cutter head (2) linearly in the X direction, said X direction linearly moving means (3) being provided on the bridge frame (4). A glass plate cutting device according to claim 2, further comprising a further ball screw (12) extending in the X direction on the bridge frame (4), and a further ball screw nut (13) screwed on the further ball screw (12) and attached rotatably to the X direction linearly moving means (3), said further ball screw nut (13) being rotated by the X direction linearly moving means (3) to move the cutter head (2) linearly in the X direction. A glass plate cutting device according to any one of claims 1 to 3, wherein said Y direction linearly moving means (111) is common to both the ball screw nuts (7, 8).

Inventors: BANDO SHIGERU, BANDO, SHIGERU
Applicants: BANDO KIKO CO, BANDO KIKO CO. LTD.
Application year: 1993
Main classification: C03B33
IPC codes: C03B33