JP5307428B2 - Tailstock with taper adjustment function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tailstock capable of covering an extended range of workpiece dimensions subjected to cylindrical grinding, and of offering workpieces cylindrically ground with good dimensional accuracy. <P>SOLUTION: The tailstock comprises: a tailstock body 1 capable of moving on a surface of a guide table 30 and of being fastened 9 at an appropriate position; a first tailstock spindle 3a with a center 5 inserted therein; a second tailstock spindle 3b surrounding the outside of the first tailstock spindle with a small space; a first center advance/retreat mechanism 70 to advance or retreat the first and second tailstock spindles simultaneously in a headstock direction; a second center advance/retreat mechanism to advance or retreat only the first tailstock spindle 3a without advancing/retreating the second tailstock spindle 3b; and a longitudinal taper adjustment mechanism to compensate for a longitudinal bias between an axis 0<SB>2</SB>of the first tailstock spindle and a center axis 0<SB>1</SB>of the first tailstock spindle. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a taper adjustable tailstock (Taper adjustable tailstock) provided in a machine tool such as a cylindrical grinding machine or a lathe. This tailstock rotates the tailstock shaft by offsetting the taper in the front-rear direction of the center shaft and the tailstock shaft when a workpiece with different dimensions is replaced with a machined workpiece. Can be corrected.

In the tailstock of the cylindrical grinding machine, each time the length of the workpiece (workpiece to be ground) changes, the tailstock slides (slids) on the guide table surface in order to change its position relative to the spindle according to the length of the workpiece. ) And moved. Therefore, the lower surface of the tailstock body that slides on the guide table surface is worn. As a result, the height position of the center in the tailstock changes and the workpiece axis is inclined, which adversely affects the machining accuracy.

As a tailstock that adjusts the taper deviation in the height direction between the center shaft and the tailstock shaft by rotating the tailstock shaft, the tailstock main body is changed to the guide table of the machine tool according to the length of the workpiece. It moves on the surface and is fastened to an appropriate position, and is fitted to the tailstock main body with a sliding piece and a rotating arm so as to be rotatable about the axis and slidable in the axial direction and fixed at an appropriate position. The workpiece is held between the center of the tip of the tailstock that can be tightened and the main shaft, and the compensation adjustment of the height position of the center that is lowered due to wear caused by the movement of the tailstock body on the guide table is the same horizontal plane. With the positional relationship above, the center axis is decentered with respect to the rotation axis of the tailstock, the base end is fixed to the tailstock with the center mounted, and the swinging end of the swinging arm extending in the radial direction is rocked by the screw mechanism. A tailstock that rotates the tailstock by displacing it in the direction of movement has been proposed and put into practical use. (E.g., see Patent Document 1.).

  On the other hand, the deviation of the longitudinal taper between the center shaft and the tailstock shaft that occurs when machining a workpiece with a different dimension with the previous machined workpiece can be corrected by rotating the tailstock. A tailstock has also been proposed. For example, an arm is integrally provided in the tailstock in the radial direction inside the tailstock, and the center is eccentrically fitted to the center of the tailstock at the tip of the tailstock, The tip of the arm is held by a pressing roller and a supporting roller that are pivotally supported by a pair of swing links. The pair of swing links are pivotally supported on a tailstock by a pressing roller and a supporting roller. The swing link on which the pressing roller is pivotally supported is biased to the arm side by a spring, the other swing link is L-shaped, the bending point is pivotally supported by the tailstock, and the other end is engaged by the adjustment shaft and the pin. They are connected together. Therefore, when the adjustment shaft moves forward and backward, the swing link operates with the bending point as a fulcrum, so that the arm is moved via the support roller, and the tailstock rotates around the axis to adjust the taper. (For example, refer to Patent Document 2).

  Since the tailstock described in Patent Document 2 is difficult to assemble, the tailstock is supported by the tailstock main body so as to advance and retreat and rotate freely, and the tip of the tailstock has a central axis of the tailstock. An eccentrically fitted center; a worm wheel attached to the rear end of the tailstock that protrudes outside the tailstock; an adjustment shaft having a worm that meshes with the wormwheel; and the tailstock A connecting block that supports the adjusting shaft and supports the adjustment shaft only by allowing rotation of the tailstock shaft, and is inserted between the connecting block and the worm wheel, and ends thereof are fixed to the worm wheel. There has also been proposed a tailstock with a taper adjustment function including a torsion spring that applies force and a cylinder that is installed on the tailstock and moves the connecting block forward and backward with respect to the tailstock (for example, See Patent Document 3.).

  Further, a center hole that is eccentric with respect to the axis is formed in the tailstock, and an axis driving means (step motor) that rotates the tailstock around the axis forward and backward, and the tailstock moves forward and backward in the axial direction. An axial drive means (hydraulic cylinder) and a rack longer than the forward / backward stroke of the tailstock shaft are provided on the tailstock shaft, the worm is eccentrically supported on the rotating shaft ship of the shaft ship circumference drive means, and the worm has a lead angle There is also known a taper-corrected tailstock that is tilted only so as to mesh with the rack so as not to restrain the tailstock from moving forward and backward (see, for example, Patent Document 4).

Furthermore, the tailstock body, a sleeve rotatably supported by the tailstock body, a means for driving the sleeve, an eccentric hole provided eccentrically with respect to the rotational center of the sleeve, and a servo in the eccentric hole A tailstock that is slidably fitted by a motor and slidable by a hydraulic cylinder, a guide hole having a substantially elliptical cross section provided in the tailstock body so as to extend parallel to the tailstock, and a guide hole A guide shaft that is loosely inserted and can move parallel to and away from the tailstock shaft, a flange that connects the guide shaft and the front end of the tailstock shaft, and a position that deviates from the center of the tailstock shaft toward the opposite guide shaft side. An offset tailstock including a center projecting from a flange has also been proposed (see, for example, Patent Document 5).

  Still further, a tailstock comprising a base moved along the guide of the bed and a main body to which the center is mounted, and an eccentric ram shaft having a center loading hole formed in an eccentric position is provided in the housing of the main body. A core height adjusting means disposed rotatably, and an elastic body interposed between the main body and the base to urge the main body horizontally and at right angles to the axis of the center, and the base There is also known a tailstock for a machine tool including a front and rear adjustment means in which an adjustment bolt is screwed into one of the main bodies and the adjustment bolt is brought into contact with the other of the base and the main body ( For example, see Patent Document 6.)

Slide the tab table groove at the bottom of the tailstock body to the left on the guide table to bring the center axis of the tailstock close to the headstock side and fix the work so that it can rotate in the direction of the workpiece axis. As a moving mechanism of a tailstock shaft that slides and removes a workpiece from the headstock in the lateral direction of the center shaft, the above-mentioned Patent Document 1 rotates the fastening handle provided on the head of the tailstock main body clockwise to support the pushing By rotating the rotating arm clockwise through the rod, the sliding piece moves forward and rides on the sloped surface of the sliding piece, and the tailstock is moved with the sliding piece and the rotating arm locked. It is proposed to take out the workpiece from between the spindle and the center fixed at the retracted end position.

Patent Document 3 discloses a moving mechanism of a tailstock shaft that moves a tailstock shaft for inserting a center forward and backward by driving a hydraulic cylinder provided below the tailstock shaft. Further, Patent Document 4 discloses a moving mechanism of a tailstock shaft that moves a tailstock shaft for inserting a center forward and backward by driving a hydraulic cylinder provided behind the tailstock shaft.

Further, a tailstock that moves a tailstock shaft for inserting a center forward and backward by driving a servo motor driven ball screw provided behind the tailstock shaft has also been proposed (for example, see Patent Document 7).

Japanese Patent Laid-Open No. 11-19806 Japanese Utility Model Publication No. 56-121501 JP-A-6-47604 JP-A-4-269102 Japanese Patent Laid-Open No. 10-34403 JP 2001-170803 A JP 2002-66805 A

When machining a workpiece by supporting the workpiece between the spindle and the center of the tailstock of a cylindrical grinding machine or lathe, the dimensions (length and thickness) of the machined workpiece are replaced with this workpiece. When the dimensions of the newly machined workpiece are different, the center is moved in the left-right direction and the tool (grindstone) table is moved back and forth. This new workpiece replacement causes the above-mentioned misalignment in the front-rear direction between the center shaft core and the tailstock shaft. Therefore, the front and rear taper is adjusted by rotating the tailstock shaft and aligning the tailstock shaft with the center shaft center. Is needed.

The length of the work table of the cylindrical grinding apparatus or lathe is limited by the size of the work to be machined. In addition, in the conventional tailstock fixing means for the tailstock, when the center projection stroke of the tailstock becomes long, when machining a deformed workpiece, the workpiece machining accuracy is poor due to rotational runout due to the deviation of the center of gravity of the workpiece. Become. Therefore, it is preferable that the center length protruding from the tailstock head is short.

Further, when removing the work from between the tailstock center and the headstock spindle, in the tailstock described in Patent Document 1, the tightening lever handle is rotated with the right hand to retract the center by 10 to 50 mm, and the restraint is released. This is convenient because the operator can perform the operation of supporting the workpiece being picked up with the left hand. However, when exchanging with a long workpiece with a different length, the center can be moved forward by moving the tailstock with the center inserted into the tailstock with a center forward retracting mechanism behind the tailstock. However, there is an advantage that the workpiece can be replaced more quickly than the tailstock that is performed by the tightening lever handle described in Patent Document 1.

  A center front retracting mechanism is provided below the tailstock shaft of Patent Document 3, and a tailstock that inserts the center of Patent Document 4 is centered on a tailstock that is provided with a longitudinal taper adjustment mechanism composed of a worm and a worm wheel. If an attempt is made to provide a mechanism for moving the tailstock shaft provided behind the push shaft, the presence of the worm and the worm wheel will be an obstacle.

  According to the present invention, two center front retraction mechanisms are provided to facilitate removal of a workpiece and attachment of a workpiece having different dimensions, and the center shaft core and the tailstock shaft core when the workpieces having different thickness dimensions are replaced. The front / rear taper adjustment provides a tailstock having the center height position compensation adjusting device described in Patent Document 1 modified to a front / rear taper adjusting mechanism.

According to the first aspect of the present invention, a tailstock main body (1) that can move on a machine tool guide table surface and can be fastened to an appropriate position, and can rotate freely around the axis and in the axial direction on the tailstock main body. A first tailstock (3a) that can be slidably fitted and can be pressed and supported at an appropriate position, and a second tailstock (3b) that surrounds the outside of the first tailstock with a slight gap. and), the the first heart tip of foot stock shaft (3a), the rotation axis of said in a positional relationship that is on approximately the same vertical plane first tailstock (3a) (O ₂₎ with respect to the center to center axis ( A center (5) in which O ₁ ) is eccentrically mounted, and a center front retraction mechanism (21) provided at the rear portion of the shaft core (O ₁ ) of the second tailstock shaft (3b). before ShisaSusumu mechanism Chapter capable of pre ShisaSusumu the first tailstock (3a) and the second cardiac time headstock direction foot stock shaft and (3b) A center front ShisaSusumu mechanism (60), the second tailstock (3b) before ShisaSusumu is allowed not but the first tailstock (3a) Second center before ShisaSusumu mechanism for front ShisaSusumu only (70) When the first heart proximal to the foot stock shaft (3a) is secured, the shaft (21) to displace the swinging lower end of a vertically extending swing rod (18) and swinging Do杆the swinging direction A tailstock (1) with a taper adjustment mechanism provided with a front and rear taper adjustment mechanism (50) for rotating the first tailstock shaft (3a) provided at the rear part of the rotary scale dial (11). It is.

  The tailstock according to the present invention is provided with two different center front retracting mechanisms in the tailstock that can retract the first tailstock that inserts the center shaft in the headstock direction of the machine tool. The workpiece can be easily removed and the workpiece can be quickly attached when changing to a workpiece having a different size.

  The longitudinal displacement between the center shaft core and the first tailstock shaft that occurs when the workpiece is replaced with a workpiece with a different thickness and the first tailstock shaft core is machined by rotating the first tailstock by the front and rear taper adjustment mechanism. The vertical displacement component of the shaft core can be compensated.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. 1 is a front view of the tailstock partly cut away, FIG. 2 is a left side view of the tailstock, FIG. 3 is a plan sectional view of the tailstock, and is viewed from the direction AA in FIG. It is a figure. 4 is a plan view of the tailstock, and FIG. 5 is a rear view of the tailstock as seen from the direction of the line BB in FIG. 6 is a cross-sectional view of the center tilt adjustment (front-rear taper adjustment) mechanism of the tailstock, and is a view taken along the line CC in FIG. FIG. 7 is a view showing the main part of the slide mechanism on the guide table of the tailstock main body, and is a right side view of the tailstock viewed from the direction of arrow D in FIG.

As shown in FIGS. 2 and 5, for example, a dovetail groove surface 2 for sliding (sliding) the guide table 30 is formed on the lower surface of the tailstock body 1 of the cylindrical grinding apparatus, and the tailstock shaft 3 is formed on the upper side. There tailstock spindle center O ₂ around rotatable and the tailstock spindle center O ₂ through holes 4 directions are fitted slidably is formed. As shown in FIGS. 1 and 3, the tailstock 3 is an appropriate position with fitted slidably rotatably and axial direction to the first tailstock center O ₂ around the tailstock body 1 A first tailstock shaft 3a that can be pressed and supported, and a second tailstock shaft having a cooling oil circulation hole 40 on the inner wall surface that surrounds the outside of the first tailstock shaft 3a with a slight gap of 8 to 12 μm. is composed of a 3b, the tip of the first tailstock spindle 3a, to roughly the same in a positional relationship that is on the vertical plane of the first tailstock 3a rotation axis O _{2 (first} tailstock core) center center center axis O ₁ is mounted eccentrically is mounted eccentrically to the tip of the first tailstock spindle 3a. In the normal position, the center axis O ₁ of the center 5 and the rotational axis O ₂ of the first tailstock spindle 3a, upward displacement components of the center axis O ₁ of the center 5 by rotation of the first tailstock spindle 3a is The positional relationship which exists on the substantially the same horizontal surface which is large is preferable. 41 is a scraper.

  As shown in FIGS. 1, 3 and 4, the center of the left end protruding portion of the center 5 which is fixed to the left of the second tailstock shaft 3b with a bolt 3c is covered with a cylindrical cavity cap 3d. In the figure, 42 is an oil plug and 43 is a hook bolt. A draw bar 5 a extends in the axial direction at the right rear end of the center 5. 90 is an O-shaped bellows.

As shown in FIG. 2, one side portion forming the dovetail groove surface 2 is fastened to the dovetail groove on the side surface of the guide table 30 by the cap nut 9 a via the flange 9, thereby enabling the guide table to move left and right.

As shown in FIGS. 6 and 7, the rotary scale dial 11 of the longitudinal taper adjusting mechanism 50 is provided on the front side of the outer housing of the tailstock body 1. A shaft 21 extending in the front-rear direction is provided on the back surface of the rotary scale dial 11. A shaft cylindrical recess 21c between the shaft 21a and the shaft 21b is formed on the front side of the shaft 21, and a sliding key 10 is provided on the tailstock frame in the right direction of the axial extension of the shaft 21b. A cam rod 18a fixed by a pin 18c is fitted below the swinging rod 18 above the concave portion of the shaft cylindrical recess 21c, and a link (base end) 18b provided on the upper end side of the swinging rod 18 is on that side. Backflushing is prevented by a small plunger 22 provided at the end. The link 18b is fastened to the outer periphery of the first tailstock shaft 3a by bolts 18d and 18d.

When the rotary scale dial 11 is scaled by one in the clockwise direction, the shaft 21 is supported by the thrust roller bearing 10a and the needle bearing 10b, rotates and moves backward to the rear side of the tailstock main body 1, and the rotational force is converted into the rotational force. The cam rod 18 a receives and rotates the swing rod 18 to rotate the first tailstock shaft 3 a so that the rotation axis O ₂ of the first tailstock shaft 3 a is 1.0 μm on the center axis O ₁ of the center 5. It is set to approach. Therefore, when the new work is replaced, the first tailstock 3a is moved forward by 150 mm, and the work is rotatably fixed between the spindle and the center 5 of the tailstock, and the rotation axis O ₂ of the first tailstock 3a When the longitudinal taper displacement of the center axis O ₁ of the center 5 is 3.0 μm, the longitudinal taper eccentricity of 3.0 μm is compensated by rotating the rotary scale dial 11 by three graduations in the clockwise direction.

Next, a description will be given of a second center front retraction mechanism that does not retreat the second tailstock shaft 3b but retreats only the first tailstock shaft 3a. As shown in FIGS. 3 and 4, at the upper center portion of the tailstock body 1, only the first tailstock 3a is moved forward in the main shaft direction (left direction) in the axial direction. An advance mechanism 60 is provided. The second center front retracting mechanism 60 has the axial spring hole 12 passing therethrough, and the front end of the spring hole 12 (the left side surface of the tailstock body) is closed by the knob 13. The spline 15a is fixed in the left-right direction with hexagon bolts 13a. Reference numeral 13b denotes an eyebolt. A compression spring 15 is connected to the right end of the spline 15a via a nut 15b, and a sliding piece 14 is slidably fitted in the axial direction at the rear end of the compression spring, and is sandwiched between the knob 13 and the sliding piece 14. A compression coil spring 15 is fitted in the spring hole 12. Therefore, the sliding piece 14 is urged in the backward direction by the spring force of the compression coil spring 15. An axially inclined surface portion 14 a is formed on the outer peripheral surface of the rear end portion of the sliding piece 14.

A pressing support rod 7 that protrudes rearward from the rear wall portion of the tailstock main body 1 (the right side surface of the tailstock main body) and has a rear opening hollow cylinder 6 that penetrates the hollow cylinder 6 in the vertical direction. Both ends thereof are rotatably supported by the hollow cylinder portion 6, and a tightening handle 8 is attached to the protruding end of the pressing support rod 7 protruding above the hollow cylinder portion 6. In the hollow cylindrical portion 6, the center portion of the rotating arm 16 is fixed to the pressing support rod 7, and one end of the rotating arm 16 is a smooth arc that can come into contact with the gradient surface portion 14 a at the rear end of the sliding piece 14. A contact portion 16a having a surface is formed, and the ball joint 16b at the other end has a first center in an engagement hole 3e opened in the outer peripheral surface of the rear end portion of the first tailstock shaft 3a protruding into the hollow cylindrical portion 6. The push shaft 3a is engaged so as to allow some rotation.

  As can be understood from FIGS. 2, 3, and 4, the upper end portion of the pressing support rod 7 is rotatably fixed to the handle base 8c, and the handle base 8c has a clamping lever handle having a grip ball 8a on the head. The eight arms 8b are fixed by the H toggle 8d. The link (base end) 18b of the rocking rod 18 described above is fixed to the rear end portion of the first tailstock shaft 3a.

In the free release state of the first tailstock 3a, the rotating arm 16 is biased in the backward direction by the spring force of the compression coil spring 15 because the contact portion 16a is in contact with the rear end surface of the sliding piece 14. Due to the sliding piece 14, the first tailstock shaft 3 a engaged with the end of the rotating arm 16 is elastically projected and advanced through the counterclockwise rotation of the rotating arm 16 in FIG. 4. It is energized. As shown in FIG. 3, the counterclockwise rotation of the tightening handle 8 (in FIG. 4, the rotation from the position of the tightening lever handle 8 indicated by the phantom line to the position of the tightening lever handle 8 indicated by the solid line). 5 moves from the right side to the left side.

Then, when the clamping lever handle 8 is rotated clockwise in FIG. 4 to retreat the tailstock shaft 3, the pressing support rod 7 is rotated and the rotating arm 16 is turned clockwise, the first tailstock shaft is rotated. The ball joint 16b fitted in the engagement hole 3e opened in the outer peripheral surface of the rear end portion 3a moves backward, and the contact portion 16a of the rotating arm 16 resists the sliding piece 14 against the spring force of the compression coil spring 15. Then, the robot moves forward and eventually rides on the slope surface portion 14a of the sliding piece 14, and the clockwise turning of the rotating arm 16 in FIG. 3 is restricted. As a result, the sliding piece 14 and the rotating arm 16 are locked, and as a result, the tailstock 3 is fixed at the retracted end position (the position of the center 5 shown on the right side in FIG. 3).

When the tightening handle 8 is turned counterclockwise in FIG. 4 in the fixed state of the retracted end position of the first tailstock shaft 3a, the engagement hole 3e opened on the outer peripheral surface of the rear end portion of the first tailstock shaft 3a. The ball joint 16b fitted in the forward movement advances, and the pivoting arm 16 pivots counterclockwise in FIG. 3, and the contact portion 16a of the pivoting arm 16 moves away from the slope surface portion 14a of the sliding piece 14, thereby sliding. The piece 14 and the rotating arm 16 are unlocked, come into contact with the rear end surface 16b of the sliding piece 14, and the sliding piece 14 biased in the backward direction rotates the rotating arm 16 counterclockwise in FIG. The first tailstock shaft 3a that engages with the end of the rotating arm 16 through the rotation is elastically biased so as to advance.

  Next, the first center front retraction mechanism 70 that simultaneously retreats the first tailstock shaft 3a together with the second tailstock shaft 3b will be described. 1, 4, and 7, 71 is a flat rotary handle, 72 is a handle, 73 is a handle collar, 74 is a clamp that rotates a screw that moves the tailstock to the left and right, 75 is a rear flange, and 76 is a handle base , 77 is a transfer ball screw, 78 is a screw base, and 79 is a front flange. When the clamp 74 is turned clockwise, the screw tightens the ball screw 77, and when the clamp 74 is turned counterclockwise, the screw is disengaged from the ball screw 77.

  When the handle 72 of the flat rotation handle 71 is rotated clockwise, the ball screw 77 rotates around the axis, and the tailstock 3 is advanced, and the center 5 moves to the center 5 shown on the left end side in FIG. . On the other hand, when the handle 72 of the flat rotary handle 71 is rotated counterclockwise, the ball screw 77 rotates around the shaft core to move the tailstock shaft 3 backward, and the center 5 is the center 5 shown on the right end side in FIG. Move to.

The first center front retraction mechanism 70 may be a combination of a hydraulic cylinder and a solenoid valve, or a combination of a servo motor and a ball screw, in addition to the combination of the flat rotary handle 71 and the ball screw 77 described above.

  Next, removal of a workpiece attached between the spindle and the center and replacement of the workpiece will be described. In order to remove the workpiece attached between the spindle and the center, the lower end of the workpiece is supported with the left hand, and the center 5 is moved 15 to 15 by rotating the clamping lever handle 8 of the second center front retraction mechanism 60 clockwise with the right hand. The workpiece is retracted by 40 mm in the axial direction to release the restraint at both ends of the workpiece, and then the workpiece is removed from between the spindle and the center 5 with the right hand attached to the workpiece. To change to a new workpiece, hold the workpiece with both hands, fit the left end of the workpiece to the main shaft, then support the workpiece with the left hand, and rotate the tightening lever handle 8 counterclockwise with the free right hand. The right end of the work is restrained at the center 5 by moving forward in the main axis direction.

  When exchanging with a workpiece having a different size, first, the first center forward retracting mechanism 70 clamp 74 is rotated counterclockwise to allow the tailstock shaft 3b to retract forward, and then the flat rotary handle 71 is rotated. After the distance tailstock shaft 3b has been moved forward and backward, the left end of the workpiece is pressed against the spindle with both hands, and then the flat rotary handle 71 is moved clockwise with the right hand. By rotating, the center 5 is advanced, and the right end of the work is restrained at the center.

Center axis O ₁ by by different work replacement dimensions and taper adjustment before and after the first tailstock center O ₂ by operating the rotating graduated dial 11 shaft 21 a required amount of rotation to the shaft cylindrical recess By moving the portion 21c in the front-rear direction, the cam rod 18a provided at the lower end of the swinging rod 18 is rotated and transmitted to the upper end side link (base end) 18b of the swinging rod 18, and the first tailstock shaft 3a is rotated. The scale dial 11 is rotated by an amount corresponding to the scale rotation amount.

Each time the workpiece thickness changes, the wheel head position is changed according to the workpiece thickness, and the taper eccentricity in the longitudinal direction of the tailstock of the center shaft and tailstock shaft caused by the thickness change is A longitudinal taper adjustment mechanism for rotating a tailstock shaft having a base end fixed to the tailstock, a swing mechanism extending in the radial direction, and a screw mechanism for displacing the swing end portion of the swing base in the swing direction. This can be performed by turning the turning scale dial 11. Therefore, it is possible to provide a first center forward retracting mechanism for inserting the center behind the center rod extending behind the center of the tailstock.

When exchanging workpieces of the same size, the center is retracted forward by the second center forward retracting mechanism. When a new workpiece with a different workpiece length is installed, the center can be moved forward and backward with the second center forward retracting mechanism, so the first center without changing the protrusion distance from the left end of the center tailstock. A function with high rigidity of the tailstock of the combination of the pushstock and the second tailstock can be used.

It is the front view which notched a part of tailstock. It is a left view of a tailstock. It is a plane sectional view of a tailstock. It is a top view of a tailstock. It is a rear view of a tailstock. It is sectional drawing of the front-back taper adjustment mechanism of a tailstock. It is a right view which shows the principal part of the slide mechanism on a guide table of a tailstock main body.

Explanation of symbols

1 Tailstock body 2 Dovetail groove surface 3 Tailstock shaft 3a First tailstock shaft 3b Second tailstock shaft O ₁ Center shaft core O ₂ First tailstock shaft core 5 Center 8 Tightening lever handle 9 Tightening flange 11 Rotation Scale dial 14 Sliding piece 18 Swing rod 18a Cam rod 18b Base end 30 Guide table 50 Front / rear taper adjustment mechanism 60 First center front retraction mechanism 70 Second center front retraction mechanism 71 Flat rotary handle 74 Clamp

Claims (1)

A tailstock body (1) that can move on the machine tool guide table surface and can be fastened to an appropriate position, and is fitted to the tailstock body so as to be rotatable about an axis and slidable in the axial direction. And a first tailstock shaft (3a) that can be pressed and supported at an appropriate position, a second tailstock shaft (3b) that surrounds the outside of the first tailstock shaft with a slight gap, and the first core the tip of the foot stock shaft (3a), mounted generally identical vertical said in a positional relationship in the plane first heart rotational axis of the foot stock shaft (3a) (O ₂₎ with respect to the center to center axis (O ₁₎ is eccentrically has been the center (5), the axis (O ₁₎ the center front ShisaSusumu mechanism a center front ShisaSusumu mechanism provided in the rear portion (21) of said second tailstock (3b) is the first cardiac foot stock shaft (3a) and a second tailstock (3b) can be pre ShisaSusumu simultaneously to headstock direction first center before ShisaSusumu mechanism 60), the second tailstock (3b) and the second center before ShisaSusumu mechanism for front ShisaSusumu only the but not before ShisaSusumu first tailstock (3a) and (70), the first heart fixed base end to the foot stock shaft (3a), vertically extending swing rod (18) and swinging Do杆rotating graduated dial shaft (21) to swing the lower end is displaced in the swinging direction of the (11 longitudinal taper adjustment mechanism for rotating said provided at the rear first tailstock (3a) of) (50), the taper adjustment mechanism with tailstock provided with a capital (1).

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