Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
  • B23B31/02—Chucks
  • B23B31/24—Chucks characterised by features relating primarily to remote control of the gripping means
  • B23B31/26—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle
  • B23B31/261—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle clamping the end of the toolholder shank
  • B23B31/266—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle clamping the end of the toolholder shank using a threaded spindle

Definitions

• the present invention is directed to the tighten ⁇ ing of tools in working machines and more particularly to an accessory device for tightening a tool in the spindle housing of a milling machine, which housing comprises a hollow spindle for receiving the tool, said device comprising a draw bar which extends through said spindle and one end of which has a thread for releasably engaging a mating thread on said tool , and means for rotating said draw bar for producing said thread engage- ment permitting tightening and fixing the tool to the spindle.
• Tool changing in a vertical milling machine is generally performed in the following way.
• the operator loosens a draw bar, the bolt head of which is placed on top of the spindle housing at a height of e.g. 1.5-1.8 m above floor level and which extends through the vertical hollow spindle.
• the draw bar which is threaded at the base, is thus screwed out of its engagement with the milling-cutter supporting cone which is loosened from the lower nose piece of the spindle from which the tool can then be removed.
• the operator has to occupy a most uncomfortable working position because he must hold the tool with one hand while simultaneously loosening the bolt head, located at an elevated working level, by means of a wrench or the like which is held with the other hand.
• the same also applies, of course, when the tool should be mounted in the spindle.
• One object of the present invention therefore is to provide a device by means of which a tool can be quickly and easily tightened in the spindle of a milling machine, without the operator having to occupy an un ⁇ comfortable working position and without the need of any additional equipment.
• Another object of the invention is to provide a tool tightening device substantially in the form of an accessory device which is easy to mount on the spindle housing of a conventional milling machine, without the need of any major modifications thereof, and which is directly connectible to the spindle of the milling machine.
• Fig. 1 shows the spindle carriage or housing of a vertical milling machine to which the invention is applicable, a portion of the spindle housing being removed at the location of the spindle shown in cross- section.
• Fig. 2 witn certain parts in cross-section, sche- atically shows a piston and cylinder assembly which is included in the accessory device according to the invention and which can be mounted on the spindle housing shown in Fig. 1.
• Fig. 3 on a larger scale, shows how a claw clutch, shown in cross-section, is fixed to a draw bar included in the accessory device according to the invention.
• a spindle carriage or housing mounted on a vertical milling machine (not shown), comprises a vertical, hollow and rotatable spindle 2 of known type. Through the spindle 2 extends a draw bar 3 having an upper thread 4 and a lower thread 5. The draw bar 3 is screwed with its lower thread 5 in an internal thread 6 of a tool, generally designated 7.
• the tool 7 is of known type and, therefore, does not call for a detailed description here.
• the tool 7 briefly comprises a mounting cone 8 conformed to the lower nose portion 9 of the spindle 2, and a milling cutter 11 fixedly mounted by means of a chucking device 10.
• the spindle 2 has a downwardly facing shoulder 12 which will be described m more detail later on.
• a piston and cylinder assembly 13 which is mounted on the spindle housing 1 schematically shown in this Figure.
• the piston and cy ⁇ linder assembly 13, the lower part of which is shown in cross-section, is preferably operated by compressed air and has a piston rod 14 which is axially movable back and forth, as indicated by the double arrow.
• the lower end of the piston rod 14 is provided with a claw clutch 15 which by the above-mentioned
• the claw clutch 15 is rigidly connected to the piston rod 14 while the claw clutch 16 has an internal thread 17 by means of which it is - ⁇ screwed on the upper thread 4 of the draw bar 3 (cf. Fig. 1).
• the claw clutch 16 engages, with its rear side, the upper end of the spindle 2.
• the piston and cylinder assembly 13 accommodates a motor 18 illustrated only schematically.
• the piston rod 14 and, thus, the draw bar 3 are rotated when the opposing claw clutches 15, 16 engage each other.
• the stroke of the piston rod 14 is accurately adjusted to the engagement between the claw clutches - 5 15, 16.
• the claws of the clutches 15, 16 are so designed, viz. bevelled, as to readily enter into engagement with each other, irrespective of the angular position of the associated rods 3, 14 prior to the engagement.
• the draw bar 3 so as to engage the upper end of the spindle 2.
• the draw bar 3 has an upper axial bore 20 which has a left-hand thread and in which a hexagon socket screw 21 is screwed for securing the claw clutch 16 to the draw bar 3. Tightening of the tool 7 by means of the device according to the invention is carried out in the fol ⁇ lowing way.
• the operator inserts the mounting cone 8 of the tool 7 in the nose portion 9 of the spindle (see Fig. 1), such that the internal thread 6 of the cone 8 comes into initial engagement with the lower thread 5 of the draw bar 3.
• the tool 7 is progressively screw ⁇ ed onto the lower thread 5 of the drawbar 3, and the cone 8 is drawn into the nose portion 9 of the spindle for a firm engagement therewith.
• the claw clutch 16 of the draw bar 3 then serves as an abutment with respect to the upper end of the spindle 2. It should be noted that the length of the lower thread 5 of the draw bar 3 must be so adjusted that the tool 7 cannot be screwed into engagement with the abutment 19.
• the spindle 2 When the tool 7 has been tightened, the spindle 2 is rotated, for milling a workpiece (not shown), by drive means (not shown) provided in the milling machine to that end.
• the piston rod 14 After mounting the tool 7 as described above, the piston rod 14 is retracted such that the claw clutches 15, 16 are disengaged from each other.
• the claw clutches 15, 16 are again brought into engagement with each other, whereupon the motor 18 rotates the asssociated piston rod 14 and, hence, the draw bar 3 counterclockwise, such that the lower thread 5 of the draw bar 3 is 6 unscrewed from the internal thread 6 of the tool 7 which can then be removed from the spindle 2. Since the claw clutch 16 of the draw bar 3 is fixed by means of a left-hand screw 21 (see Fig. 3), the abutment 19 5 of the draw bar 3 will be urged against the shoulder
• the screw 21 is dispensed with and the
• upper end portion of the draw bar extends through the associated claw clutch.
• This upper end portion has a smaller diameter than the rest of the draw bar and has an external left-hand thread on which a nut is screwed for securing the claw clutch.
• the operator need thus manipulate only the tool 7, which can be done on a .convenient working height.
• the operation of the piston and cylinder assembly 13 is carried out from a control panel which, preferably,
• the device according to the invention advanta ⁇ geously is in the form of an accessory device for use in conventional vertical milling machines.
• the piston and cylinder assembly 13 may have different fixing plates, of which one plate 22 is shown in Fig. 2. These plates are adjusted to the milling machine concerned and can be mounted direct ⁇ ly on top of the spindle housing.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Gripping On Spindles (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20372151

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (3)

• 1988
  • 1988-04-28 SE SE8801584A patent/SE8801584L/sv not_active Application Discontinuation
• 1989
  • 1989-04-28 WO PCT/SE1989/000243 patent/WO1989010226A1/en unknown
  • 1989-04-28 AU AU35347/89A patent/AU3534789A/en not_active Abandoned

Patent Citations (3)

Also Published As

Similar Documents

Legal Events