Howa Machinery, Ltd.

Hori Corporation

Tetsuya Oketani

Yoshiaki Mase

Hirotaka Nishikawa

Toshio Ito

Tadashi Uemura

Yukihiro Sakakibara

Masahiro Yoshida

Mitsutaka Hori

Hideo Uemura

A sheet cutter for cutting a sheet with a cutting blade held by a cutting blade elevating body which is elevated by one servo motor, including a pair of cutting blade elevating bodies; an elevation driving body for elevating the pair of cutting blade elevating bodies; a guide member for guiding the elevation of the pair of cutting blade elevating bodies; a holding body capable of holding the pair of cutting blade elevating bodies at an up position; and a transmission change-over device for selectively engaging the pair of cutting blade elevating bodies with the elevation driving body and selectively disengaging the pair of cutting blade elevating bodies from the elevation driving body, wherein one of the pair of cutting blade elevating bodies, which has been selected, is elevated by the servo motor.

Sheet-cutting apparatus

A spindle head having a spindle is moved along a Y-axis relative to the fixed bed of a printed-circuit board drilling machine, a work table is moved along an X-axis perpendicular to the Y-axis, and a tool magazine is moved along a .beta.-axis parallel to the Y-axis relative to the work table to bring the respective axes of the spindle and desired one of a plurality of tool posts arranged in rows and columns in the tool magazine into alignment with the axis of a pressing member included in a tool pressing mechanism fixedly held on the fixed bed under a tool changing position. The tool pressing mechanism is actuated to transfer a tool from the tool post to a chuck attached to the spindle or from the chuck to the tool post. The work table is lightweight and hence can be rapidly moved. The tool changing mechanism needs only simple control for a tool changing operation.

Tool changing mechanism

A tool position correcting device comprises a draw bar supported for axial movement in a central bore of a spindle of a machine tool, a tool holder supported for turning about an eccentric axis displaced from the axis of rotation of the spindle on the nose of the spindle, and a motion converting mechanism operatively interlocking the draw bar and the tool holder to convert the axial motion of the draw bar into the rotational motion of the eccentric rotary member. The spindle is provided with a tapered hole tapering backward in its front end, the tool holder has a tapered portion tapering backward and conforming with the tapered hole of the spindle and is held on the spindle with its tapered portion supported on balls in the tapered hole, and a spring is disposed between the spindle and the tool holder to bias the tool holder backward relative to the spindle so that the tapered portion is pressed through the balls against the tapered surface of the tapered hole so that the tool holder can be turned by a comparatively small torque when correcting the position of the cutting edge of the tool, and the composite fastening effect due to the tapered hole, the tapered portion and the spring provides a large force for holding the eccentric rotary member firmly on the spindle.

Tool position correcting device

When a spindle unit 1 rises to a tool change position P1 of a printed-circuit board drilling apparatus, a pair of cam followers 27, which have been spaced downward from a pair of operating pins 38, are brought into engagement with conical portions 39 of the operating pins 38 and caused to move toward each other. As a result, a pair of opening/closing arms 24 that are provided under a pressure foot 20 and that serve as suppressing members for preventing floating of the printed-circuit board are moved away from their suppressing positions A in which the opening/closing arms 24 are kept closed by the force of a spring 28, to their retracted positions B. Consequently, forward end portions of the opening/closing arms 24 are positioned outside a tool passage zone S through which a tool post passes when a tool is changed. As a result, the suppressing members 24 used to prevent floating of the printed-circuit board are retracted without using a drive source, when tool change is made, so that the suppressing members do not become an obstacle to performing the tool change operation.

Plate suppressing device for drilling apparatus

An indexing device comprises an indexing table fixed to a table shaft rotatably supported on a body structure. A worm shaft is rotatably supported on the body structure and has a worm formed thereon. An indexing gear is fixed coaxially to the indexing table. The indexing device has a rotation correction device for stopping the rotation of the worm shaft prior to the indexing operation of the indexing table. The indexing device further has a positioning device for operating, after the worm shaft has been thus stopped, to impart a rotational torque to the indexing table and to cause a gear tooth face of the indexing gear to press against and hold a worm tooth face of the worm, whereby the precision of positioning of the indexing table is improved.

Indexing device

A toolholder device for a machine tool comprises a holder body driven by a machine tool drive spindle, and a toolholder supported on the holder body so as to be circumferentially and axially displaceable. The holder body and the toolholder are provided with displacement detection elements which are arranged circumferentially in interdigitating relation. A support shaft extends from either member of the holder body and the toolholder toward the other member. The outer surface of the support shaft and the inner surface of a support hole of the other member to be fitted over the support shaft are formed with helical guide grooves which are opposite to each other and slopingly extends with respect to the rotational axis of the toolholder device. Balls are interposed between the opposite guide grooves to form a displacement translation mechanism which converts a rearward axial displacement of a tool and the toolholder due to overload axial thrust into a circumferential relative displacement between the adjacent detection elements. The relative displacement of the detection elements is detected by a detection unit which issues a warning signal. A compression spring in the device resists the axial displacement of the toolholder unless the axial thrust exceeds a predetermined value.

Toolholder device for machine tools

A toolholder assembly is divided into a drive toolholder coupled to the drive spindle of a machine tool, and a driven toolholder carrying a cutting tool such as a drill. The driven toolholder is coupled end to end to a drive toolholder so as to be rotatable relative to the same through a preassigned angle about the toolholder axis. A coiled torsion spring acts between the drive and the driven toolholders for torque transmission from the former to the latter. The drive and the driven toolholders have interdigitating teeth with clearances therebetween. A phase detector such as a proximity switch detects a relative phase displacement that will occur between the interdigitating teeth against the force of the torsion spring upon development of abnormal torque load on the cutting tool. Preferably, the interdigitating teeth have bevels in sliding engagement with each other for causing a relative phase displacement between the teeth upon axial displacement of the driven toolholder toward the drive toolholder, so that not only abnormal torque load but also abnormal thrust load on the cutting tool is detectable by the phase detector.

Torque and thrust overload detection system for a machine tool

An indexing apparatus for a rotary table has a support shaft rotatably supported by a base member in which indexed terminal positions of the rotary table is determined by abutment of a stopper member provided on the rotary table against positioning members provided on the base member. The indexing apparatus comprises a rack-pinion mechanism comprising a rack and a pinion fixed around the support shaft of the rotary table for rotating the same, a feed screw shaft rotatably supported by the base member and extending along the rack in a direction of the movement thereof, a breakable electric motor for driving the feed screw shaft, and a feed nut engaging the feed screw shaft. The rack and the feed nut are arranged so that either one of them has integral portions disposed at both sides of the other with spaces left on both the sides in the direction of the movement of the rack. Annular springs are disposed in each space. As the rotary indexing operation approaches the terminal position, the spring is elastically deformed in the direction of the movement of the rack so that shocks due to the abutting are prevented. Immediately before the indexed terminal positions, the speed of the motor is reduced and then the motor is braked.

Growing community of inventors

Gifu, Japan

Tetsuya Oketani