A hydraulic fluid actuated lathe tool mounting expander assembly incorporating a block having a base, an inner end, an outer end, a compression end, and a compression face; a first cylindrical void extending into the block, the first cylindrical void having a floor and opening at the block's compression face; a second cylindrical void extending into the block, the second cylindrical void having a floor and opening at the block's outer end; first and second pistons respectively slidably mounted within the first and second cylindrical voids; a conduit extending between the first and second cylindrical voids, the conduit being adapted for conveying the hydraulic fluid from the second cylindrical void to the first cylindrical void; and a jack screw actuator connected operatively to the block for driving the second piston against the hydraulic fluid for upwardly driving the first piston.

A centering clamping apparatus has a housing (1) with a centering element (2) mounted to be displaceable along a longitudinal axis between an open position and a clamping position. A finger element (3), mounted with centering element (2), is displaceable transversely to the longitudinal axis between a retracted position and an extended position. The finger element (3) is operatively connected to an adjusting member (4). The adjusting element (4) is mounted to be displaceable in the centering element (2). A blocking device (5) is provided on the centering element (2). The blocking device (5) either precludes a relative movement between the housing (1) and the centering element (2), with the finger element (3) fully retracted, or precludes a relative movement between the centering element (2) and the adjusting member (4), with the finger element (3) fully extended.

An open/shut valve mechanism for detecting that a piston member of a hydraulic pressure cylinder has reached an unclamp position comprises: a valve body reception hole that communicates with a unclamp hydraulic pressure operating chamber, a valve body movably received in the valve body reception hole and having an annular concave engagement portion on its external circumferential portion; a spherical body that is movably installed in a cylinder main body and that can engage with the concave engagement portion; and an engagement portion that is formed on an auxiliary rod and with which the spherical body can engage; and when hydraulic pressure is charged into the unclamp hydraulic pressure operating chamber and the piston member has reached its unclamp position, the valve body receives the hydraulic pressure, a portion of the spherical body engages to the engagement portion and the valve body changes over to the valve closed position; and, when the piston member has shifted from its unclamp position, the spherical body engages with the annular concave engagement portion without engaging to the engagement portion, so that the valve body is held in its open position.

When an operation portion (38) provided at an axial end portion of a valve member (37) is pushed into a valve case (31) provided to a first block (3), a clamping apparatus transitions from a first state, in which communication between: each of a primary-side pressure fluid supply/discharge port (34) and a secondary-side pressure fluid supply/discharge port (35); and a pressure fluid discharge port (36) is open, to a second state, in which communication between: each of the primary-side pressure fluid supply/discharge port (34) and the secondary-side pressure fluid supply/discharge port (35); and the pressure fluid discharge port (36) is closed.

A pallet device which can prevent a hook fixed to a pallet from interfering with a workpiece or a tool for a machine tool. The pallet device includes a pallet including a pallet main body which clamps a workpiece, and a replacement hook movably provided in the pallet main body, the replacement hook being movable between a projection position at which the replacement hook projects outside the pallet main body and a retraction position to which the replacement hook is retracted from the projection position to the pallet main body, and a jig to and from which the pallet is attached and detached.

A method of stopping vibration of a columnar work during processing thereof, includes the steps of providing a cylindrical columnar work having an outer circumferential surface divided into a non-processed region and at least two recessed processed regions with a circumferential cross-section forming a perimeter including two spaced apart non-processed perimetric segments separated by two spaced apart processed perimetric segments, providing a vibration stop including only two holding parts having arc shaped surfaces, locating the columnar work between the arc shaped surfaces of the holding parts adjacent the perimeter with each processed region radially inward, orienting the columnar work such that each arc shaped surface contacts the outer circumferential surface at both spaced apart non-processed perimetric segments with one processed perimetric segment located therebetween, each arc shaped surface, and holding the columnar work with the holding parts to prevent vibration of the columnar work during processing of the columnar work.

In a rod hole (19) of a holding rod (18) held in a guide hole (17) of a piston (10), a limit switch (20) is fixed and a detection rod (21) is inserted. A first engagement ball (30) and a second engagement ball (40) are configured to be in contact with a first cam surface (32) and a second cam surface (42), respectively, which are provided at an outer periphery of the detection rod (21). The first engagement ball (30) and the second engagement ball (40) are configured to be in contact with a first pushing portion (35) and a second pushing portion (45), respectively, which are provided inside the guide hole (17). The position of the piston (10) is detected by electrically or electronically detecting the movement of the detection rod (21) by the limit switch (20).

The workpiece fastening device of the present invention comprises a table on which a workpiece is placed, an arm which can move so as to press a workpiece on the table against the table, and a drive part which drives the arm. The arm of the workpiece fastening device comprises a connection member which is connected to the drive part, and a rotary member which is attached to the connection member to be able to rotate about a rotation axis which extends in a direction intersecting with a movement direction of the arm. The rotary member of the arm has first and second pressing parts which are arranged at the opposite sides of the rotation axis and presses a workpiece on the table against the table by the first and second pressing parts.

A hydraulic cylinder includes a rod insertion hole formed in a piston member, an auxiliary rod provided to a head side end wall member and capable of being inserted into the rod insertion hole, a rod fitting hole formed to pass through the head side end wall member and the auxiliary rod, a movable rod installed in the rod fitting hole and whose end portion toward a head side end wall projects to the exterior, a movement restriction mechanism that prohibits shifting of the movable rod in an unclamping state and permits shifting of the movable rod in a clamping state.

A switch housing body has a base and a sidewall having an axis and extending from the base to a rim and having a pair of axial slots. A switch cap has: a cap body having a top web; and a sidewall extending from the top web to a rim and having a pair of holes. A shaft passes through the pair of axial slots and pair of holes. A spring biases the cap axially away from the housing from a compressed condition to an extended condition. A cap electrical contact and a housing electrical contact have an electrically closed condition at the compressed condition.