JPS6122725Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tailstock for a machine tool that automatically displays tailstock thrust.

Conventionally, the magnitude of the gripping force when moving the tailstock shaft forward to support the workpiece between centers has often relied on the intuition of the operator. In recent years, some models have been seen incorporating a mechanism for measuring and instructing the thrust force into the tailstock, but the mechanism has become complicated and costs have increased, so it has not been widely adopted.

Therefore, the present invention aims to provide a tailstock that automatically displays the tailstock thrust corresponding to the supporting force on a scale. The handle of the feed screw is provided with a disc spring that receives the thrust acting on the body, and the handle of the feed screw is movable in the axial direction. The handle and the tailstock body are provided with an inclined cam that engages with each other between the body and the fixed collar and the handle. A movable collar whose upper part is rotatable is provided, the movable collar is always urged to rotate, and the amount of rotation of the movable collar that is rotated by the clearance of the handle due to the retreat of the feed screw is read as a thrust force. It is.

Embodiments of the present invention will be described below based on the drawings.

A tailstock shaft 2 with a center 3 fitted in a blind hole 1a drilled parallel to the bed guide surface is fitted in a tailstock body 1 fixed on the bed by a key so that it can only slide. A feed screw 4 which screws with the tailstock shaft 2 and moves it forward and backward is supported in the body 1 so that it can rotate and slide in the axial direction. A thrust bearing 5 and a disc spring 6 are interposed between a flange 4a provided midway on the screw shaft 4 and the bottom of the blind hole 1a of the body, and the disc spring 6 receives the tailstock thrust. A feed handle 8 which is prevented from rotating by a key 7 so that it can only move in the axial direction is loosely mounted between the screw shaft head 4b and the body 1 at the protruding end of the feed screw 4 protruding rearward from the body 1. A movable collar 11 is rotatably fitted in the boss portion 8a of the feed handle 8, the front end surface of which is provided with a plurality of equally sized inclined cams 10 cut in the same direction on a circumference concentric with the axis of the feed screw 4, and the collar 11
A thrust bearing 1 is provided between the feed handle 8 and the base of the feed handle 8.
A fixed collar 14, on the end surface facing the movable collar, has a plurality of inclined cams 13 cut into it to engage with the inclined cams 10 of the movable collar 11, and is fastened to the end surface of the main body 1 concentrically with the axis of the feed screw 4. A pin 15 is attached to the end surface of the movable collar 11, which is the same surface as the inclined cams 10, parallel to the handle shaft.
are planted symmetrically about the center. A groove 14a is cut into the side of the fixed collar 14 facing the movable collar in a direction perpendicular to the diameter, i.e., in the tangential direction and longer than the acting length of the ramp cam 13, and a pin 16 is planted in the groove parallel to the pin 15. The pin 15 also faces the groove 14a, and a spring 17 is stretched between the pins 15 and 16 to constantly urge the movable collar 11, whose turning direction is restricted by the ramp cam 10 engaging with the ramp cam 13, in a direction to eliminate the gap when the movable collar retreats and a gap is generated between the cam surfaces of the ramp cams 10 and 13. A scale collar 18 having a scale engraved on which the amount of turning of the base line on the movable collar 11 can be read as the tailstock thrust is fixed to the outer periphery of the fixed collar 14 so as to be position adjustable.
In addition, a compression spring 19 is interposed between the fixed collar 14 and the movable collar 11 so that when the tail thrust acts on the feed screw 4, bending the disc spring 6 and causing the feed screw 4 to retract, the feed handle 8 and the movable collar 11 retract following the screw.
Here, when the maximum deflection amount Δδmax of the disc spring 6 is equal to the cam lift of the inclined cams 10 and 13 and the inclination angle of the cam is θ, the relationship between the gap between the cam faces of the inclined cams 10 and 13 and the amount of rotation of the movable collar 11 is Δδ/tan θ, so the strength of the disc spring 6 and the inclination angle θ are appropriately selected depending on the scale width and the weight of the supporting workpiece. In addition, a feed handle that loosely mounts the movable collar 11 on the feed screw shaft may be fixed. In addition, one of the inclined cams does not necessarily have to be an inclined cam, and the protruding pin end may be in contact. Furthermore, it is also possible to eliminate the scale collar 18 and to carve the scale on the fixed collar or the movable collar. Furthermore, the multiple inclined cams may be cut obliquely to form a cylindrical surface.

The tailstock configured as described above is fixed at a position suitable for the length of the support workpiece, and the feed handle 8 is reversed to move the tailstock shaft 2 backward and widen the distance between it and the center of the main shaft (not shown). When the workpiece is conveyed between the centers, the feed handle 8 is rotated in the normal direction to advance the tailstock shaft 2 and the center 3 via the feed screw 4. When the center 3 contacts the workpiece, the tailstock 2 is stopped from moving forward, so the feed screw 4, which continues to rotate, receives the thrust and compresses the disc spring 6, causing it to retreat to a position where the spring force due to the compression and the thrust are in balance. It will be done. As the feed screw 4 moves backward, a gap is created between the feed handle 8 and the head 4b of the feed screw 4 or between the base of the feed handle 8 and the thrust bearing, but there is a gap between the fixed collar 14 and the movable collar 11. Due to the force of the compression spring 19, the movable collar 11 is moved backward together with the feed handle 8 via the thrust bearing 12, creating a gap between the movable collar 11 and the inclined cams 10 and 13.
The movable collar 11 is rotated by the force of the spring 17 stretched between the pins 15 and 16, and the inclined cam 10
and 13 engage and stop at the position where there is no gap. This amount of rotation can be immediately read as a tailstock thrust value from the position of the base line of the moving collar 11 on the scale of the scale collar 18. Therefore, the feed amount is adjusted using the feed handle 8 in consideration of the weight of the workpiece.
Next, in order to remove the workpiece, when the feed handle 8 is reversed and the tailstock shaft 2 is moved backward, the center 3 moves away from the workpiece, and the tailstock thrust acting on the feed screw 4 disappears, and the restoring force of the disc spring 6 causes the feed screw 4 to will proceed.

Along with this, the feed handle 8 is advanced against the force of the compression spring 19, and the movable collar 11 is reversely rotated against the force of the spring 17 due to the turning force and frictional force due to the slope of the slope cams 10 and 13. Cam 10.1
3 becomes in complete contact, and the base line of the moving collar 11 returns to the zero position of the scale collar 18.

In this way, according to the present invention, the structure converts the amount of deflection of the disc spring receiving the thrust of the feed screw into the amount of relative rotation between the fixed collar with the inclined cam and the movable collar, so that the thrust value can be determined from the amount of rotation. Because of this, the number of parts can be far reduced compared to the conventionally known measurement type or thrust value preset type, resulting in fewer failures and being relatively inexpensive to manufacture. In addition, since the exact thrust force is known, the thrust force is matched to the appropriate thrust force suitable for the workpiece, eliminating the risk of an unexpected disaster such as the workpiece falling off, and it also has a number of features such as no wear on the center side.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of the tailstock, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view taken along line B-B in Figure 2, mainly showing the fixed collar, moving collar, and scale collar. FIG. 4 is a diagram showing an inclined cam surface. 1... Tailstock body, 2... Tailstock shaft, 4... Feed screw, 6... Belleville spring, 8... Feed handle, 11
...Movement collar, 10/13...Slope cam, 14
... Fixed collar, 17/19 ... Spring, 18 ...
Scale color.

Claims (1)

[Scope of utility model registration request] A disc spring that receives tailstock thrust acting on the feed screw in a tailstock of a machine tool that moves the tailstock back and forth by rotating a feed screw screwed together with a tailstock shaft with a center fitted thereon by a feed handle. is provided between the flange of the feed screw and the bottom of the hole in which the tailstock shaft of the tailstock body is fitted, and a fixing collar with an inclined cam formed on the rear end surface on the circumference concentric with the feed screw is attached to the tailstock. The plate is provided with a movable collar provided at the rear of the main body and has an engaging member that engages with the slope cam of the fixed collar on an end face facing the fixed collar, which is rotatable concentrically with the feed screw and receives a tailstock thrust. When the feed screw retreats due to the deflection of the spring, it is provided so that the feed screw retreats accordingly. A tailstock with a tailstock thrust indicating scale, characterized in that a driving member for rotating the movable collar so as to eliminate a gap is provided on the movable collar or the fixed collar, and a scale for indicating the amount of rotation of the movable collar is provided.