WO2010013877A1

WO2010013877A1 - Hydraulic chuck

Info

Publication number: WO2010013877A1
Application number: PCT/KR2009/000921
Authority: WO
Inventors: Hong Suk Seo
Original assignee: Samchully Machinery Co., Ltd.
Priority date: 2008-07-28
Filing date: 2009-02-26
Publication date: 2010-02-04
Also published as: KR20100012261A; KR101008853B1

Abstract

The present invention relates to a hydraulic chuck, which includes a chuck housing having a tool insertion hole, a working space, a plurality of jaw guide grooves and a working hole; master jaws respectively and slidably assembled into the jaw guide grooves of the chuck housing, and each having inclined movement grooves, a slide groove, and first and second holding shoulders in a stepped structure; wedge pins coupled with the master jaws for lifting or lowering the master jaws; soft jaws mounted to the front surfaces of the master jaws for directly clamping and fixing a tool; a master ring for controlling clamping positions of the soft jaws; a master ring movement lever rotatively assembled into the chuck housing; wedge plungers coupled with rear parts of the wedge pins by pins; and connection elements for screw-coupling the wedge plungers with a hydraulic pipe to slide the wedge plungers right and left together with a hydraulic device.

Description

HYDRAULIC CHUCK

The present invention relates to a hydraulic chuck for machining contact surfaces of soft jaws suitable for a specific diameter into an arc shape of precise dimensions with more rapidity.

In general, a hydraulic chuck is to fix a tool when machining the tool while the tool is rotating, wherein a plurality of soft jaws radially protruded from a chuck housing support and fix the tool from an outer diameter part of the tool.

Such a hydraulic chuck includes, as shown in Fig. 6, a chuck housing 10 having a tool insertion hole 11 formed in the center of a body part to insert a tool and a plurality of jaw guide grooves 12 formed radially from the tool insertion hole 11 by penetrating the body part to the outside, jaw elements 3 coupled in the jaw guide grooves 12 of the chuck housing 10 to be fastened toward the center of the chuck housing 10 or move toward the outside of the chuck housing 10 and having inclined movement protrusions 4 at rear surfaces, and a wedge plunger 6 coupled with a rear surface of the chuck housing 10 and the inclined movement protrusions 4 of the jaw elements 3 and having coupling grooves 5 formed with guide surfaces corresponding to the inclined movement protrusions 4 to be coupled with the jaw protrusions, the wedge plungers 6 operating in connection with a hydraulic cylinder.

As the wedge plunger 6 moves forward or backward by the operation of the hydraulic cylinder, the jaw elements 3 coupled in the jaw protrusion coupling grooves 5 of the wedge plunger 6 become fastened in the direction for clamping and fixing a tool or released in the opposite direction by the inclined movement protrusions 4, which are pushed along the guide surfaces.

In the meantime, the jaw element 3 is received in the jaw guide groove and includes a master jaw 20 having the inclined movement protrusions 4, which is coupled with the wedge plunger 6, and a soft jaw 30 coupled with the master jaw 20 for grasping a tool. The jaw element 3 is substitutionally used by a worker according to the size and shape of a tool to be held or fixed in the center of the chuck precisely.

The above hydraulic chuck has, however, a disadvantage that in order to fix a tool via direct coupling between a wedge plunger and the jaw elements, the jaw elements should be changed properly according to the tool, wherein the soft jaws should be changed according to the tool or separated from or coupled with the master jaws for the control of positions thereof.

Further, even though it is easy to hold an angulated tool by the clamping fixing part, there is another disadvantage that it is likely to degrade the appearance of the tool by generating a dug mark corresponding to the shape of the clamping fixing part, since the clamping fixing part, that is, the lower end of the soft jaw has a small width and relatively large force is applied to the tool in the process of clamping the tool due to relatively small friction force between the tool and the clamping fixing part.

Recently, a tailor-made type chuck for machining tools of a predetermined diameter has been widely used. In other words, the soft jaw fastens cylindrical tools which commonly have a single set diameter and the outer diameter parts of the tools are machined through fast rotation.

The prior art tailored diameter type chuck has a clamping fixing part of a soft jaw in the arc shape approximately.

Therefore, it is not possible to machine the arc shape of the clamping fixing part to be precisely accorded with the diameter shape of a tool to machine, so that the fastening force is weak and the marks dug by the clamping fixing part appears serious.

Therefore, the present invention has been accomplished in order to solve the above-mentioned problems, and an object of the present invention is to provide a hydraulic chuck, in which a master ring is positioned to holding shoulders of master jaws and clamping fixing parts of soft jaws are machined with precise dimensions corresponding to an outer diameter of a tool to machine for increasing friction force at fastening parts so as to fix the tool stably and securely.

Another object of the present invention is to provide a hydraulic chuck in which soft jaws may fix a tool without any dug marks and may be machined precisely so as to improve reliability and marketability.

According to a first aspect of the present invention, there is provided a hydraulic chuck, including a chuck housing having a tool insertion hole formed in the center of a front surface of a body part to insert a tool, a working space formed at a rear part with a diameter larger than that of the tool insertion hole for receiving various tools, a plurality of jaw guide grooves formed at uniformly divided positions toward the center of rotation and a working hole formed outside the body part inward; master jaws respectively and slidably assembled into the jaw guide grooves of the chuck housing, and each having inclined movement grooves formed at both sides with inclination, a slide groove formed longitudinally at a front surface to slidably receive a connection element having a screw hole, and first and second holding shoulders in a stepped structure at a lower part of a rear surface; wedge pins having inclined cams to be fitted into the inclined movement grooves of the master jaws for lifting or lowering the master jaws according to forward or backward movement caused by oil pressure; soft jaws mounted to the front surfaces of the master jaws by screw-coupling bolts into the screw holes of the connection elements, and each having an inner part protruded toward the tool insertion hole of the chuck housing to directly clamp and fix the tool; a master ring having an elongated guide groove outside in the longitudinal direction for mounting a tool, and mounted outside the tool insertion hole of the chuck housing for controlling clamping positions by being held by the first and second holding shoulders of the master jaws; a master ring movement lever rotatively assembled into the working hole of the chuck housing and having an eccentric shaft eccentrically formed at an end to be fitted into the guide groove of the master ring and a deviation preventing part for preventing deviation from the mounting state thereof; wedge plungers coupled with rear parts of the wedge pins by pins; and connection elements for screw-coupling the wedge plungers with a hydraulic pipe to slide the wedge plungers right and left together with a hydraulic device.

According to the present invention as above, the master ring does not generate interference in the lowering operation of the master jaws so as to recognize a tool normally when the master ring is retreated by the operation of the master ring movement lever.

If the master ring moves forward by the operation of the master ring movement lever, the master ring generates interference in the lowering operation of the master jaws so that the master jaws becomes lowered as much as the soft jaws become held by the first holding shoulders, and the soft jaws are subject to cutting to have a desired diameter in this state.

Therefore, the clamping fixing parts of the soft jaws may be cut to an inner diameter corresponding to an outer diameter of a machining target article by means of a bite.

The master ring movement lever has grooves at the deviation preventing part to secure a stop ball at most advanced and most retreated positions of the master ring with respect to the master jaws, and is screw-coupled with the rear surface of the body part of the chuck housing by a movement lever control bolt for preventing the deviation of the stop ball and spring after the stop ball and the spring are fitted thereto.

In the hydraulic chuck in the above structure according to the present invention, the master ring may be controlled in the position right and left so that an inner diameter of the clamping fixing parts of the soft jaws is machined by a bite according to an outer diameter of a tool to machine at fastening positions where the outer diameter of the master ring is held by the first holding shoulders after the master ring moved to the position of the master jaws.

Therefore, the clamping fixing parts of the soft jaws may contact the tool to machine in the arc shape equal to the outer diameter of the tool in the shape and size, thereby holding the center of the tool precisely.

In addition, when the master ring moves backward, the master ring does not interfere the lowering of the master jaws for the complete recognition of the tool normally.

Further, the contact areas of the clamping fixing parts are wide so that the friction force becomes increased, making the fastening force improved and stabilized, thereby improving the reliability and marketability.

The objects, features and advantages of the present invention will be more clearly understood from the preferred embodiments in the following detailed description in conjunction with the accompanying drawings, in which:

Fig. 1 is an exploded perspective view showing a hydraulic chuck according to a preferred embodiment of the present invention;

Fig. 2 is a cross-sectional view of the hydraulic chuck coupled with a soft jaw according to the present invention;

Fig. 3 is a cross-sectional view for explaining the cutting of the soft jaw according to the present invention;

Fig. 4 is a cross-sectional view of the soft jaw in the cut state according to the present invention;

Fig. 5 is a side view showing the state of the soft jaw according to the present invention; and

Fig. 6 is an exploded perspective view showing a prior art hydraulic chuck according to the present invention.

Now, a hydraulic chuck according to the present invention will be described in more detail with reference to preferred embodiments in conjunction with accompanied drawings.

Fig. 1 is an exploded perspective view of a hydraulic chuck according to a preferred embodiment of the present invention, in which a chuck housing, master jaws, soft jaws, a master ring and a mater ring movement lever are exploded. Fig. 2 is a cross-sectional view showing an initial state that the soft jaw is coupled in a chuck housing according to the present invention. Fig. 3 a cross-sectional view showing the cutting of a soft jaw in the state that the lowering depth of the soft jaw is limited by placing a master ring, which is placed to first holding shoulders of master jaws by rotating a master ring movement lever. Fig. 4 is a cross-sectional view showing the state that the soft jaw fixes a tool without interference in the lowering depth of the master jaw by placing the master jaws at the second holding shoulders by returning the master ring movement lever to an initial state, and Fig. 5 is a side view showing the state that the clamping fixing parts at the lower ends of the soft jaws are formed equally to an outer diameter of a tool.

Now, referring to Fig. 1, a chuck housing 10 has a tool insertion hole 11 in the center of a body part to insert and position a tool, and a working space 18 formed with a diameter larger than that of the tool insertion hole 11 at a rear part for receiving various elements, for example, a wedge plunger, a hydraulic pipe 71, a connection element 70 and the like.

A plurality of jaw guide grooves 12 are formed at uniformly divided positions on an outer peripheral surface of a front end of the chuck housing 10 so that the master jaws 20 are slidingly movable as being assembled into the chuck housing 10.

The jaw guide groove 12 is formed in the shape of dovetail or rectangle having an opened front surface part, and a master jaw 20, which is designed in the corresponding shape and size to the jaw guide groove, is fitted therein by sliding.

The chuck housing 10 has a working hole 19 inward formed outside the body part to be inserted by a master ring rotation lever 50 so as to alternatively manipulate a master ring 40 to move forward or backward.

The master jaw 20 fitted into the jaw guide groove 12 has inclined movement grooves 21 at both side surfaces with a predetermined inclination angle so that inclination cams 25a, which are formed in wedge pins 25 by the same inclination angle, are assembled into the inclined movement grooves 21.

Therefore, as the connection element 70, which connects the hydraulic pipe 71 with the wedge plunger 60, moves backward by a hydraulic system, the wedge pins 25, which are respectively connected to the wedge plunger 60 by pins 61, move backward (to the left in Fig. 4), changing the positions of the inclination cams 25a, so that the respective master jaws 20 move to the center of the chuck housing 10 in the fastening direction.

To the contrary, as the hydraulic pipe 71 moves forward by the oil pressure of the hydraulic system, the wedge plunger 60 screw-coupled with the connection element 70 moves forward together with the wedge pins 25, so that the master jaws 20 spread toward the outside of the chuck housing 10. A soft jaw 30 is coupled with a front surface of the master jaw 20 via the connection element 22 by inserting a bolt 33 into a screw hole 28.

Therefore, if the master jaw 20 and the soft jaw 30 move toward the center of the tool insertion hole 11 simultaneously in the fastening direction, it is possible to grasp a tool to fix or release the tool.

That is, as the hydraulic pipe 71 moves forward by the oil pressure of the hydraulic system, the wedge pins 25 coupled with the wedge plungers 60 by the pins 61 moves forward and the master jaw 20, which is fitted with the inclination cams 25a of the pin wedges 25 in the inclined movement grooves 21, moves in the fastening direction to that the master jaw 20 and the soft jaw 30 hold a tool in the fixing direction along the jaw guide groove 12 of the chuck housing 10. If the oil pressure of the hydraulic system applies reversely, the master jaw 20 and the soft jaw 30 move to release the fastening state of the tool.

The master jaw 20 is formed with a first shoulder 23 and a second shoulder 24 in the inward stepped manner at a lower part of a rear surface, and the master ring 40 is guided to the horizontal part of the connection element 70 outside the tool insertion hole 11 of the chuck housing 10 so as to be positioned slidably right and left.

The master ring 40 has an elongated guide groove 41 at an outer diameter part thereof to be parallel to the movement direction of the wedge pins 25, and the master ring movement lever 50 is fitted into the assembling hole 19 of the chuck housing 10.

The master ring movement lever 50 has an eccentric shaft 52 at an end, wherein the eccentric shaft 52 is eccentrically protruded with a small diameter to be fitted into the guide groove 41 of the master ring 40.

Therefore, the master ring 40 becomes moved via straight sliding according to the rotation direction that a user manipulate the master ring movement lever 50 in the state that the eccentric shaft 52 is fitted into the guide groove 41.

That is, in order to normally recognize a tool by the master ring 40, the master ring 40 is positioned at the left side as shown in Fig. 4.

In this case, a right end of the master ring 40 is positioned at the second shoulders 24, so that the master ring 40 makes any interference in the movement of the master jaws 20 and the soft jaws 30 in the fastening direction as described above.

If the master ring movement lever 50 is rotated and the master ring 40 is moved right through the contact between the guide groove 41 and the eccentric cam 52 as shown in Fig. 3, the end of the master ring 40 is positioned at the first shoulders 24 of the master jaws 20.

In this case, the first shoulders 24 of the master jaws 20 are held by the right upper end of the master ring 40, generating interference in the lowering depth in the fastening direction of the master jaws 20 and the soft jaws 30, when the master jaws 20 and the soft jaws 30 are driven in the fastening direction by the action of the hydraulic system, wherein the inner diameter parts of the soft jaws 30 are cut by means of a cutting tool B in this state.

The cutting of the inner diameter parts of the soft jaws 30 as above is to make the inner diameter size of the soft jaws 30 equal to the that of a diameter of a tool to recognize, thereby improving the recognition force without making any defects in the tool in the clamping state.

Further, in order for a worker to recognize the advanced or retreated position of the master ring movement lever 50 in the right and left direction, the movement lever control bolt 53 is fitted with a stop ball 60 and a spring 61 for preventing deviation and then screw-coupled with a rear surface of a body part of the chuck housing 10.

The master ring movement lever 50 is formed with grooves 55 for securing the stop ball 60 at the most advanced and retreated positions of the master ring 40 with respect to the master jaws 20.

Therefore, the advanced or retreated position of the master ring 40 may be sensuously recognized by a worker when the worker rotates the master ring movement lever 50.

In order to machine a tool normally in the clamping fixing parts 31 of the soft jaws 30 as shown in Fig. 4 and Fig. 5, first, the master ring movement lever 50 is rotated to the initial position thereof and then the eccentric shaft 52, which is fitted in the guide groove 41, is rotated and the right end of the master ring 40 is retreated to the position of the second shoulder parts 24. In this state, the interference of the master ring 40 in the lowering of the master jaws 20 is released, so that the soft jaws 30 coupled with the master jaws 20 may be lowered further and the tool may be hold and fastened by the clamping fixing parts 31 of the soft jaws 30.

At this time, the fastening operation is unlikely to be disturbed since a gap enough to fasten the tool is secured between the second shoulders 24 of the master jaws 20 and the master ring 40.

According to the present invention in the above structure, the clamping fixing parts 31 of the soft jaws 30 may be machined according to an outer diameter of a tool in the precise shape and size by simple manipulation, so that the clamping contact areas are increased to improve the friction force and fix the tool without any damage.

Claims

Hydraulic chuck, comprising:

a chuck housing having a tool insertion hole formed in the center of a front surface of a body part to insert a tool, a working space formed at a rear part with a diameter larger than that of the tool insertion hole for receiving various tools, a plurality of jaw guide grooves formed at uniformly divided positions toward the center of rotation and a working hole formed outside the body part inward;

master jaws respectively and slidably assembled into the jaw guide grooves of the chuck housing, and each having inclined movement grooves formed at both sides with inclination, a slide groove formed longitudinally at a front surface to slidably receive a connection element having a screw hole, and first and second holding shoulders in a stepped structure at a lower part of a rear surface;

wedge pins having inclined cams to be fitted into the inclined movement grooves of the master jaws for lifting or lowering the master jaws according to forward or backward movement caused by oil pressure;

soft jaws mounted to the front surfaces of the master jaws by screw-coupling bolts into the screw holes of the connection elements, and each having an inner part protruded toward the tool insertion hole of the chuck housing to directly clamp and fix the tool;

a master ring having an elongated guide groove outside in the longitudinal direction for mounting a tool, and mounted outside the tool insertion hole of the chuck housing for controlling holding positions by being held by the first and second holding shoulders of the master jaws;

a master ring movement lever rotatively assembled into the working hole of the chuck housing and having an eccentric shaft eccentrically formed at an end to be fitted into the guide groove of the master ring and a deviation preventing part for preventing deviation from the mounting state thereof;

wedge plungers coupled with rear parts of the wedge pins by pins; and

connection elements for screw-coupling the wedge plungers with a hydraulic pipe to slide the wedge plungers right and left together with a hydraulic device.
The hydraulic chuck as claimed in claim 1, wherein the deviation preventing part of the master ring moving lever has grooves for securing a stop ball at most advanced and most retreated positions of the master ring with respect to the master jaws, and a movement lever control bolt is fitted with the stop ball and a spring and then screw-coupled to the rear surface of the body part of the chuck housing for preventing deviation.