Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D57/00—Sawing machines or sawing devices not covered by one of the preceding groups B23D45/00 - B23D55/00
  • B23D57/003—Sawing machines or sawing devices working with saw wires, characterised only by constructional features of particular parts
  • B23D57/0053—Sawing machines or sawing devices working with saw wires, characterised only by constructional features of particular parts of drives for saw wires; of wheel mountings; of wheels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D51/00—Sawing machines or sawing devices working with straight blades, characterised only by constructional features of particular parts; Carrying or attaching means for tools, covered by this subclass, which are connected to a carrier at both ends
  • B23D51/16—Sawing machines or sawing devices working with straight blades, characterised only by constructional features of particular parts; Carrying or attaching means for tools, covered by this subclass, which are connected to a carrier at both ends of drives or feed mechanisms for straight tools, e.g. saw blades, or bows
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D57/00—Sawing machines or sawing devices not covered by one of the preceding groups B23D45/00 - B23D55/00
  • B23D57/0007—Sawing machines or sawing devices not covered by one of the preceding groups B23D45/00 - B23D55/00 using saw wires
  • B23D57/0023—Sawing machines or sawing devices not covered by one of the preceding groups B23D45/00 - B23D55/00 using saw wires with a plurality of saw wires or saw wires having plural cutting zones

Definitions

• This invention relates to a drive mechanism which will enable a flexible member to be reciprocated in the direction of its length without distorting or bending the flexible member.
• the invention is particularly applicable to driving an elongated flexible cutting member.
• Elongated flexible members having cutting formations thereon are in common use and are normally supported in a tensioned condition in a rigid frame so that they may be reciprocated together in the direction of elongation for the purpose of performing a cutting function.
• This construction is acceptable in many situations, such as in a conventional powered hacksaw or jigsaw, however the weight of the moving component is such that the inertia forces developed severely restrict the speed of operation and hence the cutting speed.
• there are other applications of elongated flexible cutting members wherein it is not convenient to provide the appropriate rigid support structure to maintain the cutting member in the tensioned state.
• the drive mechanism usually includes a simple crank drive system that cannot be correctly balanced, and thus causes a serious problem at high speed operation. Further, when a simple crank is used to impart linear motion to a member, the velocity of the linear motion varies within each stroke. This creates a major problem if a respective crank mechanism is coupled to each end of a rigid member or a member that is required to be maintained taut during reciprocation.
• a construction meeting this object would facilitate the use of elongated flexible cutter members capable of making relatively deep cuts without the interference normally presented by the structure supporting the flexible cutting member.
• a drive mechanism to reciprocate a finite length elongated flexible member in the direction of elongation thereof comprising two drive units mounted a fixed distance apart and each adapted to have a respective end of the flexible member coupled thereto, each drive unit comprising motor means operatively coupled to a drive member to reciprocate same, and tension means adapted to interact with the drive member whereby in use a flexible member extending between the drive units and coupled at the ends thereof to the respective drive members, is maintained in tension throughout the reciprocating movement thereof.
• each tension means apply a respective force to the opposite ends of the flexible member in mutually opposite directions whereby the flexible member is in tension throughout the reciprocating movement thereof in either direction.
• each drive unit includes a mechanism operably interposed between the motor means and the drive member whereby the rotary motion of the motor is converted to a substantially pure straight line reciprocatory motion.
• this motion conversion is achieved by a hypocycloidal gear train that produces pure reciprocatory movement from rotatory motion.
• This mechanism only involves pure rotary or linear motion and thus can be fully balanced.
• means are provided to rotate the flexible member about the longitudinal axis thereof as the flexible member is reciprocating.
• the extent of rotatory motion is preferably through at least 90° and preferably 360° in either direction from a central disposition. Conveniently the flexible member can rotate in either direction through unlimited revolutions.
• the drive mechanism as above proposed is particularly applicable to driving a linear cutting member that performs a cutting action when reciprocated in the direction of the length thereof.
• Cutting members of this form are required to be longitudinally tensioned in operation, and if required to cut in more than one plane in a single operation, must be free of cutter support structure spanning the workpiece in the vicinity of the linear cutting member.
• the present invention is particularly applicable to a linear cutting member as commonly used in cutting two dimensional shapes from block materials such as foamed materials including flexible and rigid.
• the drive mechanism as above described is arranged with one drive unit mounted on respective frame members located on opposite sides of an area whereon the material to be cut is supported.
• the drive units are arranged to be moved in unison along the frame members so the flexible cutting member can cut material located between the frame members.
• the material to be cut is supported to be movable in a direction normal to the movement of the drive units along said frame members. This enables two dimensional shapes to be cut from the material by the flexible cutter member.
• a second drive mechanism supporting a second elongated flexible cutting member may be arranged on the frame with the second cutting member operating in a plain at right angle to the other cutting member thereby enabling the cutting of the material to provide three dimensional shapes.
• Figure 1 is a perspective schematic arrangement of a foam block cutting machine incorporating a support and drive mechanism for a flexible cutting member as proposed by the present invention.
• Figure 2 is a sectional view through one of the drive mechanisms as seen in Figure 1.
• FIG 3 is a sectional view through a modified mounting of the drive unit.
• the table 10 comprises two co-planar sections 11 and 12 with a narrow gap therebetween as indicated at 13.
• the stationary rectangular frame 15 is supported in fixed relation to the table 10 and having two vertically spaced horizontal tracks 16 and two horizontal spaced vertical tracks 17.
• Each track supports a respective drive unit 18 which shall be described in further detail hereafter.
• Respective elongated flexible cutting members 19 and 19a are supported by a respective pair of the drive units 18 supported on the respective parallel tracks so as to provide support and horizontal reciprocation to the one cutting member 19 and support and vertical reciprocation to the other cutting member 19a.
• the above structure is specifically designed for cutting foam block material which can be supported on the table 10 and progressively fed through the opening 13 defined by the frame 15 and subjected to cutting action by the respective horizontal and vertical cutting members 19, 19a as the foam block is fed through the frame 15.
• Each of the pairs of drive units 18, supporting the respective horizontal and vertical cutting members 19 and 19a can be independently moved along the respective tracks 16 and 17, as the foam block supported on the table 10 is passed through the frame 15.
• the movement of the table 10 and the respective drive units 18 along the respective tracks 16 and 17 is under a computer control mechanism, to produce, the required shaped cuts in the foam material.
• each drive unit 18 comprises a conventional electrical motor 20 mounted on a gearbox 21 with which there is integrally formed a gas chamber 22.
• Each gear box is adapted to be mounted on a respective track formed on the frame member so the drive unit can be moved therealong.
• the gearbox houses a planetary gear train comprising a carrier 23 coupled to the shaft 24 of the motor 20, by the rubber coupling 38.
• the shaft 24 is supported in the axial spaced bearings 25 mounted in the external wall and sleeve 26 of the gearbox 21 respectively.
• the internally toothed gear 27 is fixedly mounted in the sleeve 26 co-axial with the common axis of the motor shaft 24 and carrier 23.
• the carrier 23 rotatably supports the pinion shaft 28 in bearings 29 and 30.
• the pinion shaft carries the externally toothed pinion gear 31 which meshes with the internally toothed stationary gear 27. The number of teeth on the pinion 31 is half that of the stationary internal gear 27.
• This gear train is known as the Murray hypocycloid.
• the carrier 23 and pinion shaft 28 include balance weights 23a and 28a so that they are respectively balanced.
• Journalled on the crank pin 33 is a connecting rod 34 rigidly connected to the piston 35 supported in the cylinder 36.
• the cylinder 36 is rigidly connected with the gear box 21 and in communication with the gas chamber 22 via the series of apertures 37 in the wall of the cylinder 36. Because the gear train above described is of a hypocycloidal form, the crank pin 33 will reciprocate in a single plane passing through the axis of the carrier 23, and the axis of the cylinder 36 and piston 35 are located in the same plane whereby the connecting rod 34 is always subjected to pure reciprocating movement and remains co-axial with the piston 35 and cylinder 36.
• the drive rod 40 is connected at the end 41 to the piston 35 with the thrust bearing 42 interposed therebetween.
• the drive rod 40 is free to rotate relative to the piston 35.
• Adjacent the opposite end of the cylinder 36 the drive rod 40 is supported for axial sliding movement in the sleeve 43 and projects outwardly of the gear box 21 to support the coupling 44.
• the sleeve 43 is in turn rotatably supported by bearings 45 and 46 in the cylinder 36, with a seal 47 interposed between the internal surface of the cylinder and the external surface of the sleeve.
• the drive rod 40 is connected to the sleeve 43 so that it may freely slide axially relative to the sleeve 43 but is restrained against rotation relative to the sleeve 43.
• This relation may be achieved by the drive rod 40 being of square section and slidable in a close fitting relation in a square passage through the sleeve 43.
• Secured to the sleeve is a control pulley 48 whereby rotation of the pulley 48 by the motor 39 will affect corresponding rotation of the drive rod 40 and coupling 44.
• the motor 39 is coupled by the toothed drive belt 61 to the pulley 48 to eliminate slippage therebetween.
• the drive units 18 connected to the respective ends of the cutting member 19, 19a have the respective motors 39 thereof operable in synchronism so that by rotation of the respective pulleys in unison, the attitude of the cutter member is changed to suit the desired direction of cut in the foam block.
• the gas chamber 22 is filled with gas under pressure when the drive unit is in operation whereby there is provided a force acting in the direction of the arrow A in Figure 2 applied to the drive rod 40 through the piston 35.
• the pressure of the gas is selected so that when two drive units are coupled to the respective ends of a flexible cutting member, as hereinafter described, the drive 5 rod 40 will always be in tension irrespective of which direction the rod is moving in the cylinder 36.
• drive units constructed as shown in Figure 2 are arranged in pairs, one on each of the two vertical tracks 17, and one on each of the two horizontal tracks 16, as shown in Figure 1.
• both the drive rods at the respective ends thereof are in tension, although to differing degrees, with the net positive tension being in the direction in which the cutting member is moving.
• FIG 3 there is shown in simplified form one drive unit 56 of the construction described with reference to Figure 2 mounted on a frame 52 which is in use mounted on one of the tracks 16 or 17, to linearly move therealong.
• the frame 52 has two parallel rails 50 one on either side of the drive unit.
• the drive unit 56 is connected to each of the rails 50 by guide sleeves members 51 formed integral with the drive unit, and each have a linear bearing 53 therein to allow the drive unit 56 to freely slide along the rails 50.
• pistons 49 Connected to the frame 52 are two pistons 49 slidably received in cylinder 57 communicating with and extending laterally into the gas chamber 22 of the drive unit.
• This piston 49 and rail 50 arrangement allows the drive unit 56 to have limited linear movement relative to the frame 52 in the direction of the drive rod 40.
• a stop shoulder 54 is provided at the end of the frame 52 opposite to the pistons 49 and arranged so that the piston 49 remains within the cylinder 57 when the drive unit abuts the stop shoulder.
• the drive unit mounted on the guide rails 40 can move relative to the frame 52 and hence relative to the particular track on the frame 15 to accommodate variations in the length of the cutting member 19, including variates arising when fitting a replacement cutter member, or expansion and contraction of the cutting member due to temperature changes.
• the above drive mechanism for the cutting member enables it to be of a relatively thin flexible nature, it is possible to change the orientation of the cutting member to the material being cut so that non straight or contoured cuts can be made by effecting the necessary change in attitude of the flexible cutting member.
• This can be achieved by operation of the motor 39 to rotate the pulleys 48, sleeve 43 and drive rod 40 of the respective drive units in unison.
• Each of the motors 39 are controlled by an ECU programmed to adjust the orientation of the cutting edge of the cutting member in accordance with the shape to be cut from the material fed to the cutting member.
• each of the drive units 18 are supported on a respective track 16 or 17 for movement horizontally or vertically respectively.
• the two drive units on the vertical tracks 17 move therealong in unison in either direction with the cutter member 19 maintained horizontal and taut therebetween.
• the two drive units on the horizontal tracks 16 move therealong in unison in either direction and maintain the cutter member 19a vertical and taut therebetween.
• the respective drive units that move in unison can be moved under the control of respective synchronised motors or by a single motor coupled to each drive unit.
• the movement of the drive units along the respective tracks is controlled by an ECU that can be programmed to move the respective cutting member in a manner to produce products of the desired shape.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Control Of Cutting Processes (AREA)
• Transmission Devices (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=3776313

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (1)

Citations (6)

Family Cites Families (2)

• 1993
  • 1993-07-13 GB GB9501187A patent/GB2283453B/en not_active Expired - Fee Related
  • 1993-07-13 DE DE4393341T patent/DE4393341T1/de active Pending
  • 1993-07-13 WO PCT/AU1993/000347 patent/WO1994002276A1/en active Application Filing
  • 1993-07-13 DE DE4393341A patent/DE4393341B4/de not_active Expired - Fee Related
• 1995
  • 1995-01-20 DK DK199500064A patent/DK174042B1/da not_active IP Right Cessation

Patent Citations (6)

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