GB2343644A

GB2343644A - Chuck device

Info

Publication number: GB2343644A
Application number: GB9925652A
Authority: GB
Inventors: Takaaki Yamaura
Original assignee: Showa Corp
Current assignee: Showa Corp
Priority date: 1998-11-10
Filing date: 1999-10-29
Publication date: 2000-05-17
Anticipated expiration: 2019-10-29
Also published as: GB9925652D0; JP2000141111A; GB2343644B; ID25966A; BR9905356A; CN1253059A; CN1092331C; JP4067202B2

Abstract

A chuck deuce 20 comprises a housing member 22 pressing and dosing a chuck tip end portion 21A of a chuck member 21 from the outer periphery thereof to thereby cause the chuck tip end portion 21A to catch a workpiece 4 and a core member 23 pressing and opening the chuck tip end portion 21A of the chuck member 21 from the inner periphery thereof to thereby release the workpiece 4 from the chuck tip end portion 21A.

Description

CHUCK DEVI ! CE The present invention relates to a chuck device for catching a sticklike work or work piece such as the piston rod of a hydraulic shock absorber.

There is known, as a conventional chuck device, one comprising a chuck member which has a chuck tip end portion elastically deformable in opening direction and a housing member which presses and closes the chuck tip end portion of the chuck member from the outer periphery thereof and which causes the chuck tip end portion to catch a work If the chuck member catches the work, the chuck device of this type operates such that the housing member is moved relative to the chuck member in the direction in which the housing member presses the chuck tip end portion of the chuck member from the outer periphery thereof to close the chuck tip end portion of the chuck member, thereby catching the outer periphery of the work Also, if the work is released from the chuck member, the chuck device operates such that the housing member is moved relative to the chuck member in the direction in which the action of the housing member to press the tip end portion of the chuck member from the outer periphery thereof is released and that the chuck tip end portion of the chuck member is elastically opened by spring action to thereby release the work.

The conventional technique has, however, the following disadvantages: (1) While the chuck end portion of the chuck member is forcedly operated in one closing direction, the chuck device relies solely on the elastic recovery force of the chuck member in the opposite direction to the closing direction, ie., opening direction. Thus, the conventional chuck device may lack in closinglopening promptness and reliability.

0 The opening diameter of the chuck tip end portion of the chuck member is based on a spontaneous return behavior by means of the elastic recovery force of the chuck member and the opening diameter is difficult to widen. Due to this, when the work is inserted into the opening chuck tip end portion of the chuck member, the work may collide against the inner periphery of the chuck tip end portion. As a result, for example, a spring portion is disadvantageously damaged when the outer periphery of the work is processed with screws, thereby deteriorating the salability of the chuck device.

It is, therefore, an aim of the present invention to enhance the opening/closing promptness and reliability of a chuck device and to widen the opening diameter of a chuck tip end portion.

The present invention is a chuck device for catching a stick-like work, comprising a chuck member having a chuck tip end portion elastically deformable in closing and opening directions ; a housing member pressing and closing the chuck tip end portion of the chuck member from an outer periphery and causing the chuck tip end portion to catch the work; a core member pressing and opening the chuck tip end portion of the chuck member from an inner periphery to thereby release the work from the chuck tip end portion; and an actuator pushing and pulling the core member and the housing member in a direction in which the core member and the housing member contact with and separate from the chuck member, wherein when the actuator pulls the core member and the housing member, the core member is moved with respect to the chuck tip end portion of the chuck member, pressing of the core member on the chuck tip end portion is released and then the housing member presses the chuck tip end portion to thereby catch the work, and when the actuator pushes the core member and the housing member, the housing member is moved with respect to the chuck tip end portion of the chuck member, pressing of the housing member on the chuck tip end portion is released and then the core member presses the chuck tip end portion to thereby release the work.

The present invention is also a chuck device for catching a stick-like work, comprising a chuck member having a chuck tip end portion elastically deformable in closing and openino-directions ; a housing member pressing and dosing the chuck tip end portion of the chuck member from an outer periphery and causing the chuck tip end portion to catch the work, a core member pressing and opening the chuck tip end portion of the chuck member from an inner periphery to thereby release the work from the chuck tip end portion ; and an actuator coupling the core member to the housing member with a pin, the core member relatively movable with respect to the pin by a fixed length in a direction in which the core member contacts with and separates from the chuck member, pushing and pulling the core member in the direction in which the core member contacts with and separates from the chuck member, wherein when the actuator pulls the core member, the core member is moved with respect to the chuck tip end portion of the chuck member, pressing of the core member on the chuck tip end portion is released and then the housing member presses the chuck tip end portion to thereby catch the work, and when the actuator pushes the core member, the housing member is moved with respect to the chuck tip end portion of the chuck member, pressing of the housing member on the chuck tip end portion is released and then the core member presses the chuck tip end portion to thereby release the work The present invention will be more fully understood from the detailed description given below and from the accompanying drawings which should not be taken to be a limitation on the invention, but are for explanation and understanding only.

The drawings FIG. 1 is a typical view showing a hydraulic shock absorber performance evaluation tester ; FIG. 2 is a typical view showing a chuck device; FIG. 3 is a typical view showing the important parts of the chuck device shown in FIG. 2; and FIG. 4 is a typical view showing the operating steps of the chuck device.

A hydraulic shock absorber performance evaluation tester 10 is capable of evaluating the performance of a hydraulic shock absorber 1. The hydraulic shock absorber 1 has a structure, as shown in FIG. 2, in which an inner cylinder 3 is inserted into a bottomed cylindrical outer cylinder 2, a piston rod 4 is slidably inserted into the inner cylinder 3 and a rod guide 5, a sealing member 6 and an end plate 7 are disposed on the upper end portion of the inner cylinder 3 within the outer cylinder 2. At this moment, in the hydraulic shock absorber 1, the interior of the inner cylinder 3 which serves as an oil chamber is filled with oil and an oil pool chamber, a gas chamber above the oil pool chamber are formed between the outer cylinder 2 and the inner cylinder 3 and the upper portions of the outer cylinder 2 and the inner cylinder 3 are sealed tight with the above-stated sealing member 6.

As shown in FIG. 1, the tester 10 has a structure in which the outer cylinder 2 of the hydraulic shock absorber 1 can be supported upright by a clamp base 12 movable vertically along a slide guide 11 provided on the lower front portion of a column 10A and in which the clamp base 12 can be elevated by a damp cylinder 13. In addition, the tester 10 has an elevation head 15 which can be elevated along a slide guide 14 provided on the upper front portion of the column lOA This elevation head 15 is coupled to the coupling rod 18 of a crank unit 17 driven by an elevation motor 16. The elevation head 15 has an automated chuck device 20 provided with a load gauge 19 to allow the chuck device 20 to hold the tip end screw portion 4A of the piston rod 4 extending externally through the sealing member 6 from the outer cylinder 2 of the hydraulic shock absorber 1.

With this structure, the elevation head 15 is moved vertically by the elevation motor 16 in a state in which the tip end screw portion 4A of the piston rod 4 of the hydraulic shock absorber 1 supported upright by the clamp base 12 is held by the chuck device 20 of the elevation head 15, and the tester 10 measures the gas reaction force and damping force of the hydraulic shock absorber 1 based on the expansion stroke of the piston rod 4 and on the output value of the load gauge 19.

Meanwhile, as shown in FIGS. 2 and 3, the chuck device 20 has a chuck member 21, a housing member 22, a core member 23, a pin 24 and an actuator 25.

The chuck member 21 is a cylindrical body which is coupled to the lower end face of the cylinder 25A of the actuator 25 supported by the elevation head 15 through the load gauge 19 and which e. xtends downward.

The tip end side of the cylindrical body becomes a claw-like chuck tip end portion 2LA circuSerentially separated by a plurality of slits. The chuck tip end portion 21A is elastically deformable in openingtclosing direction (radial direction) in a free state. A screw surface 21B is provided on the inner peripheral surface of the tip end of the chuck tip end portion 2 LA so as to engage with and hold the tip end screw portion 4A of the piston rod 4 of the hydraulic shock absorber 1.

The housing member 22 is a cylindrical body fitted into the outer peripheral side of the chuck member 21. The housing member 22 presses and closes the chuck tip end portion 21A of the chuck member 21 from the outer periphery thereof to allow the chuck end portion 21A to hold the tip end screw portion 4A of the piston rod 4. The housing member 22 moves aially with respect to the chuck member 21 as wil be described later and a tapered closing pressing portion 22A on the tip end of the housing member 22 presses the chuck tip end portion 21A of the chuck member 21 from the outer periphery thereof and reduces the diameter of the chuck tip end portion 21A The core member 23 is a rod-shaped body fitted into the inner peripheral side of the chuck member 21. The core member 23 presses and opens the chuck tip end portion 21A of the chuck member 21 from the inner periphery thereof to thereby release the tip end screw portion 4A of the piston rod 4 from the chuck tip end portion 21A As wil be described later, the core member 23 is moved adally with respect to the chuck member 21 and the tapered opening pressing portion 23A presses the chuck tip end portion 21A of the chuck member 21 from the inner periphery thereof to thereby widen the diameter of the chuck tip end portion 21A.

The pin 24 is inserted into the long hole 23B of the core member 23 and the hde 22B of the housing member 22 to couple the core member 23 and the housing member 22. The pin 24 can freely, vertically move the slit 21C of the chuck member 21. At this moment, the core member 23 can be relatively moved by a fixed length"a"or the lost-motion length of the long hole 23B with respect to the pin 24 in the direction in which the core member 23 contacts with and separates from the chuck member 21 or axial direction.

The actuator 25 contains a piston 25B in the cylinder 25A, couples the proximal portion of the core member 23 with the piston 25B, thereby allowing the core member 23 to be pushed or pulled in the direction in which the chuck member contacts with and separates from the chuck member 21 or axial direction. At this time, the actuator 25 may be a double acting cylinder device operated by a fluid pressure circuit (pneumatic circuit) using a five-port solenoid valve 26 shown in FIG. 2 (A) or a single acting cylinder device returned with a spring force and operated by a fluid pressure circuit (pneumatic circuit) using a three-port solenoid valve 2 l shown in FIG. 2 (B).

In the chuck device 20, therefore, the chuck tip end portion 21A is opened in a state in which the actuator 25 causes the opening pressing portion 23A of the core member 23 to press the chuck tip end portion 2 LA of the chuck member 21 and the tip end screw portion 4A of the piston rod 4 can be thereby inserted into/pulled from the chuck tip end portion 21A (FIG. 4 (C)). The maximum opening diameter Dl of the chuck tip end portion 21A is larger than the bore diameter Do of a work inlet 22C on the lowest end portion of housing member 22 to ensure that the collision of the tip end screw portion 4A of the piston rod 4 guided and inserted by a work guide 22D having a chamfered tip end of the work inlet 22C against the screw surface 21B of the chuck tip end portion 21A is avoided (FIG. 4 (C)). The bore diameter Ds of the chuck tip end portion 21A in a free state in which the chuck tip end portion 21A of the chuck member 21 is not pressed by the housing member 22 nor the core member 23, is set almost equal to the bore diameter Do of the work inlet 22C of the housing member 22 (FIG. 4 (D)).

Further, in the chuck device 20, the chuck tip end portion 2 LA of the chuck member 21 is closed in a state in which the actuator 25 causes the dosing pressing part 22A of the housing member 22 to press the chuck tip end portion 21A, to thereby allow the screw surface 21B of the chuck tip end portion 21A to hold the tip end screw portion 4A of the piston rod 4 (FIG. 4 (A)).

Now, the chuck operation of the chuck device 20 will be described (FIG. 4).

(1) Closing operation of the chuck device 20 from an opening state (FIGS. 4 (C), (D), (A)) From the opening state of the chuck device 20 shown in FIG. 4 (C) Cm which the chuck tip end portion 2 1A has the maximum opening diameter D), the core member 23 is pulled by the actuator 25. By doing so, the core member 23 is moved upward by the above-stated length"a"with respect to the chuck tip end portion 21A of the chuck member 21 (until the lower edge portion of the long hole 23B of the core member 23 strikes at the pin 24), to thereby release the pressing of the opening pressing portion 23A of the core member 23 on the chuck tip end portion 21A (at which time, the bore diameter of the chuck tip end portion 21A is D2) (FIG. 4 (D)). Thereafter, the actuator 25 pulls the core member 23 further, whereby the core member 23 is moved further upward and the housing member 22 is pulled upward through the pin 24. Then, the closing pressing portion 22A of the housing member 22 presses and closes the chuck tip end portion 21A (the housing member 22 is pulled by a length b) to thereby allow the tip end screw portion 4A of the piston rod 4 to be held by the screw surface 21B of the chuck tip end portion 21A (FIG. 4 (-A)).

(2) Opening operation from the closed state of the chuck device 20 (FIGS. 4 (A), (B), (C)) From the closed state of the chuck device 20 shown in FIG. 4 (A), the core member 23 is pushed by the actuator 25. By doing so, first, the core member 23 is moved downward by the above-stated length"a"with respect to the chuck tip end portion 21A of the chuck member 21 (until the upper edge portion of the long hole 23B of the core member 23 strikes at the pin 24) (at which time the opening pressing portion 23A of the core member 23 does not press the chuck tip end portion 21A yet). The actuator 25 pushes the core member 23 further, thereby moving the housing member 22 downward with respect to the chuck tip end portion 21A of the chuck member 21 and releasing the pressing of the closing pressing portion 22A of the housing member 22 on the chuck tip end portion 21A Thereafter, the opening pressing portion 23A of the core member 23 presses the chuck tip end portion 21A and opens the chuck tip end portion 21A to have the maximum opening diameter Dl (the housing member 22 and the core member 23 are pushed down by the length b), to thereby release the tip end screw portion 4A of the piston rod 4 from the screw surface 21B of the chuck tip end portion 21A (FIG. 4 (C)).

Therefore, the following actions are done in this embodiment : (D The chuck device 20 comprises both the housing member 22 closing the chuck member 21 and the core member 23 opening the chuck member 21. Due to this, the chuck tip end portion 2LA of the chuck member 21 is forcedly, actively driven in both opening and closing directions, whereby the opening/dosing promptness and reliability of the chuck device 20 can be enhanced.

) The chuck tip end portion 2 LA of the chuck member 21 is forcedly widened by the core member 23 from the spontaneous opening state by an elastic recovery force and the opening diameter of the chuck tip end portion 21A can be widened. If the screw portion 4A is provided on the outer periphery of the work, in particular, the outer periphery of the work can be introduced into the chuck tip end portion 2 LA mithout collision, for example.

Thus, the availability of the chuck device 20 can be enhanced.

() The housing member 22 is coupled to the pin 24 with which the core member 23 pushed or pulled by the actuator 25 can be relatively moved by a fixed length. Therefore, it is possible to shift timing at which the core member 23 presses the chuck tip end portion 2LA of the chuck member 21 from timing at which the housing member 22 presses the chuck tip end portion 21A thereof by using a single actuator 25. Thus, the above-stated actions (D and (2) can be realized with a simple constitution.

@ The work inlet 22C of the housing member 22 is provided with the work guide 22D having a chamfered tip end and the maximum opening diameter Dl of the chuck tip end portion 21A of the chuck member 21 is set larger than the bore diameter Do of the work inlet 22C of the housing member 22. Due to this, the piston rod 4 can be guided by the work guide 22D of the housing member 22 and can be smoothly introduced into the chuck member 21 without the fear that the piston rod 4 might collide against the chuck tip end portion 21A of the chuck member 21 in a state in which the opening diameter of the chuck tip end portion 2 LA is widened.

Furthermore, in the above-state chuck device 20, the single actuator 25 allows the housing member 22 and the core member 23 pushed and pulled through the pin 24. According to the present invention, however, (a) the single actuator 25 may allow the housing member 22 and the core member 23 to be pushed and pulled through another mechanical structure instead of the pin 24; or (b) an actuator for the housing member 22 and that for the core member 23 may be individually provided to thereby allow the housing member 22 and the core member 23 to be pushed and pulled by means of these actuators, respectively.

The embodiment of the present invention has been described so far with reference to the drawings. The concrete constitution of the present invention should not be, however, Iimited to this embodiment and design modifications and the like may be included in the present invention as long as such modifications do not deviate from the scope of the present invention. For example, in the embodiment of the present invention, the actuator 25 constituting the chuck device 20 may not be limited to a cylinder device and may be another mechanical structure driven by, for example, gears.

As can be seen from the above description, the present invention can enhance the opening/dosing promptness and reliability of the chuck device widen the opening diameter of the chuck tip end portion.

Although the invention has been illustrated and described with respect to several exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made to the present invention without departing from the spirit and scope thereof. Therefore, the present invention should not be understood as limited to the specific embodiment set out above, but should be understood to include all possible embodiments which can be embodied within a scope encompassed and equivalents thereof with respect to the feature set out in the appended claims.

Claims

WNAT T, CI. A 1. A chuck device for catching a stick-like work, comprising a chuck member having a chuck tip end portion elastically deformable in closing and opening directions; a housing member pressing and closing the chuck tip end portion of said chuck member from an outer periphery and causing the chuck tip end portion to catch the work ; a core member pressing and opening the chuck tip end portion of said chuck member from an inner periphery to thereby release the work from the chuck tip end portion; and an actuator pushing and pulling said core member and said housing member in a direction in which said core member and said housing member contact with and separate from said chuck member, wherein when said actuator pulls said core member and said housing member, said core member is moved with respect to the chuck tip end portion of said chuck member, pressing of the core member on the chuck tip end portion is released and then said housing member presses the chuck tip end portion to thereby catch the work, and when said actuator pushes said core member and said housing member, said housing member is moved with respect to the chuck tip end portion of said chuck member, pressing of the housing member on the chuck tip end portion is released and then said core member presses the chuck tip end portion to thereby release the work.
2. A chuck device for catching a stick-like work, comprising. a chuck member having a chuck tip end portion elastically deformable in closing and opening directions ; a housing member pressing and closing the chuck tip end portion of said chuck member from an outer periphery and causing the chuck tip end portion to catch the work; a core member pressing and opening the chuck tip end portion of said chuck member from an inner periphery to thereby release the work from the chuck tip end portion; and an actuator coupling said core member to said housing member with a pin, the core member relatively movable with respect to said pin by a fixed length in a direction in which the core member contacts with and separates from said chuck member, pushing and pulling the core member in the direction in which the core member contacts with and separates from the chuck member, wherein when said actuator puIls said core member, said core member is moved with respect to the chuck tip end portion of said chuck member, pressing of the core member on the chuck tip end portion is released and then said housing member presses the chuck tip end portion to thereby catch the work and when said actuator pushes said core member, said housing member is moved with respect to the chuck tip end portion of said chuck member, pressing of the housing member on the chuck tip end portion is released and then said core member presses the chuck tip end portion to thereby release the work.
3. The chuck device according to claim 1 or 2, wherein said housing member is provided with a work inlet for introducing the work toward the chuck tip end portion of said chuck member and a work guide having a chamfered tip end around the work inlet; and a maximum opening diameter of the chuck tip end portion of the chuck member pressed and opened by said core member is set larger than a bore diameter of the work inlet of the housing member.