Clamp device

Abstract

An output part is provided to the left end of a clamp arm that is supported by a housing so as to be slidable in the vertical direction. At the left end of the housing, a first hole for spring fitting opens obliquely upward towards the output part. A through hole that links the upper surface and the lower surface of the clamp arm is disposed obliquely upward at a left-leaning part of the clamp arm. A second hole for spring fitting and a female screw hole are formed, in that order, upwards in the through hole. A return spring that is installed through the first hole and the second hole impels the output part upwards. A push bolt that is screwed into the female screw hole rom above compresses the return spring.

Claims

1. A clamp device comprising: a clamp arm extending along a housing in a horizontal direction, the clamp arm including a fulcrum portion which is swingably supported by the housing at a middle portion in the horizontal direction, an input portion which is provided at a base end thereof in the horizontal direction, and an output portion which is provided at a leading end thereof in the horizontal direction; a cylinder hole formed in the housing and below the input portion so as to extend in an up-down direction and be opened in an upper surface of the housing; a piston inserted into the cylinder hole, the piston being configured to advance to above an opening end of the housing to move the input portion upward; a working chamber which is formed between a bottom wall of the cylinder hole and the piston and which a pressure fluid is supplied into and discharged from; a first hole formed near a leading end portion of the housing so as to be opened obliquely upward toward a leading end-adjacent portion of the clamp arm; a through hole formed between the output portion and the fulcrum portion so as to extend obliquely upward and provide communication between an upper surface and a lower surface of the clamp arm, the through hole including a second hole and a female screw hole which are formed so as to extend upward; a return spring mounted in the first hole and the second hole and configured to bias the output portion upward, wherein a spring receiver is provided in the second hole that is configured to engage an upper end portion of the return spring; and a pressing bolt screwed into the female screw hole from above that engages the spring receiver to compress the return spring, wherein the female screw hole has an upper part formed as a counter bore and a lower part having threads that match threads of the pressing bolt, wherein an inner diameter of the second hole is larger than an inner diameter of the female screw hole.

2. The clamp device according to claim 1, wherein at least an upper half portion of the cylinder hole is formed so as to extend straight in the up-down direction; and at least an upper half portion of the piston is formed so as to extend straight in the up-down direction.

3. The clamp device according to claim 2, wherein an inclination angle of an axis of the first hole with respect to an axis of the cylinder hole is set within a range of 30 degrees to 45 degrees.

4. The clamp device according to claim 1, wherein an inclination angle of an axis of the first hole with respect to an axis of the cylinder hole is set within a range of 30 degrees to 45 degrees.

5. The clamp device according to claim 4, wherein the inclination angle is set within a range of 35 degrees to 45 degrees.

6. The clamp device according to claim 1, wherein said clamp device is mounted on a support stand.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional elevation view of a release state in a clamp device according to an embodiment of the present invention.

(2) FIG. 2 is a left side view of the clamp device shown in FIG. 1.

(3) FIG. 3 is a right side view of the clamp device shown in FIG. 1.

(4) FIG. 4 is a plan view of the clamp device shown in FIG. 1.

(5) FIG. 5 is a cross-sectional elevation view showing a lock state of the clamp device.

DETAILED DESCRIPTION OF THE INVENTION

(6) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, the structure of a clamp device 10 will be described with reference to FIGS. 1 to 4 showing a release state prior to fixing an object to be fixed.

(7) The clamp device 10 according to the present invention is mounted on a support stand 1 such as a table when being used. A T-leg 30 is formed at a lower portion of a housing 12 and fitted into a T-groove 32 formed in the support stand 1, so as to be movable in a horizontal direction (a right-left direction in FIG. 1).

(8) At the left end side (leading end side) of the housing 12 in FIG. 1, a pair of right and left side walls 34a are provided in a standing manner as shown in FIG. 2. A groove 34 having a U shape in a side view is formed between the side walls 34a. A pivotal support shaft 36 is provided to both side walls 34a and at a middle portion of the housing 12 in the right-left direction, and a fulcrum portion 14a provided at a middle portion of a clamp arm 14 in a longitudinal direction thereof is rotatably supported by the pivotal support shaft 36. In addition to the fulcrum portion 14a, the clamp arm 14 includes: an input portion 14b which is provided at the right end side (base end side) of the clamp arm 14; and an output portion 14c which is provided at the left end side (leading end side) of the clamp arm 14.

(9) Meanwhile, at the right end side (base end side) of the housing 12 in FIG. 1, a cylinder hole 16 is formed at a position corresponding to the input portion 14b so as to be opened in an upper surface of the housing 12 and extend straight over the entirety thereof in an up-down direction. A piston 18 is hermetically inserted into the cylinder hole 16 via a sealing member 38. The piston 18 is formed so as to extend straight over the entirety thereof in the up-down direction, and advances to above the opening end of the cylinder hole 16 to move the input portion 14b upward. In addition, a scraper 40 is mounted at an opening edge portion of the cylinder hole 16.

(10) A working chamber 20 is formed between the piston 18 and a bottom wall 16a of the cylinder hole 16. A pressure oil as a pressure fluid is supplied into or discharged from the working chamber 20 through a supply/discharge port 42.

(11) A first hole 22 for mounting a spring is formed near a left end portion of the housing 12 so as to be opened obliquely upward toward a left end-adjacent portion of the clamp arm 14. An inclination angle θ of an axis C2 of the first hole 22 with respect to an axis C1 of the cylinder hole 16 is set preferably within a range of 30 degrees to 45 degrees and more preferably within a range of 35 degrees to 45 degrees. When the inclination angle θ is set within such a range, an arm length between an axis of the pivotal support shaft 36 and a location at which a biasing force of a later-described return spring 26 is applied to the clamp arm 14, is increased. Thus, the return spring 26 is allowed to increase a rotary force with respect to the clamp arm 14. As a result, it is possible to further rapidly return-drive the clamp arm 14 without increasing the size of the housing 12, the return spring 26, or the like.

(12) Meanwhile, a through hole 24 is formed in the clamp arm 14 and between the output portion 14c and the fulcrum portion 14a so as to extend obliquely upward and provide communication between an upper surface and a lower surface of the clamp arm 14. The through hole 24 is provided so as to be substantially coaxial with the axis C2 of the first hole 22 in the release state. A second hole 24a for mounting a spring and a female screw hole 24b are formed in the through hole 24 in this order so as to extend upward. As described later, the return spring 26 is mounted in the first hole 22 and the second hole 24a in a free state, and is compressed by a pressing bolt 28 screwed into the female screw hole 24b from above, thereby biasing the output portion 14c upward. It should be noted that in order to prevent the pressing bolt 28 from being loosed, the pressing bolt 28 is preferably rotated to be fully fastened.

(13) In addition, a projection 14d formed on a left end side lower surface of the clamp arm 14 and a left end side upper surface 12a formed in the housing 12 so as to receive the projection 14d serve as a stopper which prevents the piston 18 from coming out of the cylinder hole 16.

(14) The return spring 26 includes: an outer spring 26a which has a large diameter; and an inner spring 26b which has a small diameter and is inserted into the outer spring 26a. Each of the outer spring 26a and the inner spring 26b is composed of a compression coil spring. A lower end portion of the return spring 26 is received by a bottom wall of the first hole 22 of the housing 12. An upper end portion of the return spring 26 is received by the pressing bolt 28 via a spring receiver 44 inserted into the second hole 24a of the clamp arm 14.

(15) As shown in FIGS. 1 and 5, the clamp device 10 having the above configuration operates as follows.

(16) In the release state of FIG. 1, the pressure oil in the working chamber 20 is discharged therefrom, and the output portion 14c of the clamp arm 14 is pressed up and the input portion 14b is pressed down by the biasing force of the return spring 26, thereby moving the piston 18 downward.

(17) In lock-driving the clamp device 10, the pressure oil is supplied into the working chamber 20 in the release state of FIG. 1.

(18) Accordingly, as shown in FIG. 5, the pressure oil in the working chamber 20 moves the piston 18 upward, the piston 18 presses up the input portion 14b of the clamp arm 14, and the output portion 14c is pressed down against the return spring 26. Thus, the output portion 14c presses a mold D against an upper surface of the support stand 1.

(19) In switching the clamp device 10 from the lock state of FIG. 5 to the release state of the FIG. 1, the pressure oil in the working chamber 20 is discharged therefrom in FIG. 5 described above.

(20) Accordingly, the output portion 14c of the clamp arm 14 is pressed up by the biasing force of the return spring 26, and the input portion 14b moves the piston 18 downward, thereby returning to the release state of FIG. 1. Thus, fixing of the mold D is released.

(21) The clamp device 10 according to the embodiment described above has the following advantages.

(22) In assembling or disassembling the clamp device 10, when the clamp arm 14 is mounted in or dismounted from the groove 34 of the housing 12, the pressing bolt 28 is rotated to be loosed to decrease the biasing force of the return spring 26, thereby allowing the pivotal support shaft 36 to easily be inserted into or pulled out from the housing 12.

(23) In addition, since the stopper for the piston 18 is composed of the projection 14d provided on the left end side lower surface of the clamp arm 14 and the left end side upper surface 12a of the housing 12 which is formed so as to receive the projection 14d, it is unnecessary to provide a stopper portion at an upper portion of the cylinder hole 16. Thus, it is possible to simplify the structure of the cylinder hole 16 or the piston 18. As a result, the clamp device 10 is excellent in productivity and maintainability.

(24) Moreover, by changing the machining dimensions of either one of the projection 14d on the left end side lower surface of the clamp arm 14 or the left end side upper surface 12a of the housing 12, it is possible to handle pistons 18 having various strokes. Thus, it is possible to share components. As a matter of course, the machining dimensions of both the projection 14d on the left end side lower surface of the clamp arm 14 and the left end side upper surface 12a of the housing 12 may be changed.

(25) The embodiment described above can be changed as follows.

(26) The pressure fluid which is supplied into or discharged from the working chamber 20 is not limited to the exemplified pressure oil, and may be compressed air, another compressed gas, or the like.

(27) Although the clamp device 10 is not equipped with moving means, positioning means, and the like, the clamp device 10 may be reciprocated between a predetermined advance position and a predetermined retreat position on the support stand 1 by an actuator such as an electric motor or a hydraulic cylinder.

(28) The case has been shown in which a dual spring composed of the outer spring 26a and the inner spring 26b is used as the return spring 26. However, for example, the return spring 26 may be composed of a single spring.

(29) In addition, the case has been shown in which the spring receiver 44 is mounted at the upper end of the return spring 26. However, in the case where the return spring 26 can be compressed by only the pressing bolt 28, it is possible to omit the spring receiver 44.

(30) In the embodiment described above, the case has been shown in which as a mounted attitude of the clamp device 10, the longitudinal direction of the clamp arm 14 is directed in the horizontal direction. However, the longitudinal direction of the clamp arm 14 may be directed in a vertical direction or an oblique direction.

(31) In addition, the case has been shown in which the clamp device 10 is movably mounted on the support stand 1 by means of the T-leg 30 and the T-groove 32. However, a manner in which the clamp device 10 is mounted on the support stand 1 is not limited thereto, and the clamp device 10 may be fixed to the support stand 1 by means of a bolt.

(32) The case has been shown in which the cylinder hole 16 and the piston 18 are formed so as to extend straight over the entirety thereof in the up-down direction. However, at least of an upper half portion of each of the cylinder hole 16 and the piston 18 may be formed so as to extend straight in the up-down direction.

DESCRIPTION OF THE REFERENCE CHARACTERS

(33) 10 clamp device

(34) 12 housing

(35) 14 clamp arm

(36) 14a fulcrum portion of clamp arm 14

(37) 14b input portion of clamp arm 14

(38) 14c output portion of clamp arm 14

(39) 16 cylinder hole

(40) 18 piston

(41) 20 working chamber

(42) 22 first hole

(43) 24 through hole

(44) 24a second hole

(45) 24b female screw hole

(46) 26 return spring

(47) 28 pressing bolt

(48) C1 axis of cylinder hole 16

(49) C2 axis of first hole 22

(50) θ inclination angle