Information
-
Patent Grant
-
6742777
-
Patent Number
6,742,777
-
Date Filed
Monday, November 4, 200222 years ago
-
Date Issued
Tuesday, June 1, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Birch, Stewart, Kolasch & Birch, LLP
-
CPC
-
US Classifications
Field of Search
US
- 269 71
- 269 82
- 269 83
- 269 74
- 269 63
- 269 50
- 269 51
- 269 69
- 403 166
-
International Classifications
-
Abstract
A one way clamp mechanism C is composed of a clamping section 7 provided with a clamp pawl 10 and a locking section 8 in which an outer guide 22 of the clamping section 7 is slidably provided on a smaller diameter section 31 of the locking section 8. The one way clamp mechanism C is also composed of an inclined plane 28 provided on the outer guide 22, a lock ball 33 housed in a long opening 32 of a small diameter section 31, and a first spring 34. The lock ball 33 is biased to move in a locking direction (shown by the arrow A) by the first spring 34 and the clamping section 7 is biased to move in a locking direction by a second spring 37.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clamping device for use in an assembly process of a workpiece such as a motorcycle engine in which the workpiece is supported on a work bench, and more particularly to an efficient clamping operation. The clamping operation includes both movements for clamping and unclamping the wirkpiece.
2. Description of the Prior Art
A clamping device for a motorcycle engine is disclosed in Japanese Unexamined Patent Publication No. SHO 59-169739 (1984) in which a pair of clamp pawls for supporting the engine from both sides is provided. In this prior art, one clamp pawl is fixedly secured and the other clamp pawl is movably provided. Accordingly, even though a size of an engine supporting section is changed, the pair of clamping pawls can be used in common by adjusting the clamp pawl on the movable side.
Since the positional adjustment of the clamp pawl on the movable side is computer-controlled, the clamping device becomes complicated and expensive. It is therefore desirable that a device with a comparatively simple construction be provided in which the clamping operation can be efficiently performed by a manual operation. It is therefore an object of the present invention to meet such requirements as described above.
SUMMARY OF THE INVENTION
To solve the problems, a clamping device according to the present invention has a clamping section for clamping a workpiece movably provided on a guide shaft in the axial direction and is characterized in that a locking section for fixedly securing the clamping section in position on the guide shaft is provided to move on the guide shaft in a locking direction and in a unlocking direction and that the locking section forms a one way mechanism whereby when the locking section is moved in the locking direction, it prevents only the movement of the clamping section in the unclamping direction relative to the workpiece and when the locking section is moved in the unlocking direction, it makes the movement of the clamping section free.
In this case, the one way mechanism can be composed of an inclined plane formed on one side of fitting sections in which each part of the clamping section and the locking section is fitted into one another in a relatively slidable manner, a supporting recession long in the axial direction of the guide shaft formed on the other side facing the inclined plane, a lock ball housed in the supporting recession to axially move between the inclined plane and the guide shaft, a first spring adapted to bias the lock ball in the locking direction, and a second spring adapted to bias the locking section in the locking direction relative to the clamping section.
In the present invention, when the clamping section is manually moved on the guide shaft to move the locking section in a locking direction in a clamping position of a workpiece, only the movement of the clamping section in the unclamping direction is prevented to be in a locking position.
Further, in this locking position, if the locking section is moved in the unlocking direction, locking by the one way mechanism is released to allow the clamping section to move on either side in the axial direction of the guide shaft. In this manner, support or release of the workpiece can be effected in a single operation. Thus, it is possible to realize a clamping device with a relatively simple construction at a low cost. It is also possible to improve a working efficiency in a clamping operation.
Further, the one way mechanism comprises the inclined plane provided on one side of the fitting sections, the supporting recession provided on the other side thereof, the lock ball housed in the supporting recession, the first spring for biasing the lock ball in the locking direction, and the second spring for biasing the locking section in the locking direction. Accordingly, once the locking section is released, it is moved in the locking direction by the second spring to push the lock ball against the inclined plane, thereby bringing the one way mechanism into a locking condition. On the contrary, if the locking section is pulled in the unlocking direction against the second spring, the lock ball is separated from the inclined plane to bring the one way mechanism into an unlocking condition, thereby unclamping the lock ball by a single operation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a front view showing an entire clamping device according to the present invention;
FIG. 2
is an enlarged plan view of the clamping device;
FIG. 3
is an enlarged cross-sectional view taken along the line
3
—
3
of
FIG. 1
; and
FIG. 4
is an enlarged view showing a one way mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
One embodiment of the present invention will now be explained with reference to the accompanying drawings.
FIG. 1
is a front view showing an entire clamping device of the present embodiment and
FIG. 2
is an enlarged plan view thereof
FIG. 3
is an enlarged cross-sectional view taken along the line
3
—
3
of FIG.
1
.
FIG. 4
is an enlarged view of a one way mechanism.
Referring first to
FIGS. 1 and 2
, a clamping device
2
is mounted on a work bench
1
. The clamping device
2
comprises a base
3
fixedly secured to the work bench
1
, a rotating table
4
rotatably supported by the base
3
, a supporting platform
5
fixedly secured onto the central section of the rotating table
4
, a guide shaft
6
of which the central section is secured to the supporting platform
5
and which extends in the diametric direction crossing above the rotating table
4
, and a clamping section
7
and a locking section
8
each provided to make a pair on each end of the guide shaft
6
in the axial direction. The clamping section
7
has an arm section
9
projecting in the radial direction and the arm section
9
is provided with a clamp pawl
10
.
A work bench
11
integrally formed with the rotating table
4
is also provided. The work bench
11
is made of a suitable plastic material which is softer than the rotating table
4
. As shown in
FIG. 2
(not shown in FIG.
1
), a rotation lock member
12
for the rotating table
4
is provided on the work bench
1
to rotate around a central axis
13
. The rotation lock member
12
is provided on its one end with a lock pawl
14
which engages engaging recessions
15
formed on the outer periphery of the rotating table
4
to perform rotation and rotational positioning of the rotating table
4
.
Mounted on the work bench
11
is a crank case
17
of a motorcycle engine
16
which is a workpiece. The crank case
17
is provided with an engine hanger section
18
projecting from the rear end section thereof and supported between a pair of clamp pawls
10
which are adapted to engage an installation opening
19
(see
FIG. 3
) formed on the engine hanger
18
from both sides.
As fully shown in
FIGS. 3 and 4
, the clamping section
7
and the locking section
8
in the clamping device
2
are respectively provided apart to make a pair on each side of the guide shaft
6
and adapted to axially move along the guide shaft
6
in the direction of the arrow A or in the direction of the arrow B. In the locking section
8
, the direction of the arrow A is a locking direction, while the direction of the arrow B is an unlocking direction. Stopper plates
20
are installed on each end of the guide shaft
6
by bolts
21
to prevent the locking section
8
from coming out.
The clamping section
7
and the locking section
8
form a one way mechanism C. In
FIG. 4
in which one side of the one way mechanism is shown, the clamping section
7
is provided with a substantially cylindrical outer guide
22
and a substantially disk-like clamp base
23
. An outer periphery of the clamp base
23
is put on top of a flange section
24
integrally formed with the outer guide
22
to be fastened by a bolt
25
for integration. Part of the clamp base
23
is extended in the radial direction to serve as the arm section
9
through which a small diameter section
26
of the clamp pawl
10
on one side is passed. Part of the small diameter section
26
is provided with the thread of a screw to be firmly fastened by a nut
27
.
The outer guide
22
is provided on its inner periphery with an inclined plane
28
gradually expanding outside in the radial direction toward the axial end of the guide shaft
6
. The locking section
8
is integrally to move formed with a large diameter section
30
of which the outer periphery is knurled for hand gripping during operation and a small diameter section
31
adapted to engage the inner periphery of the outer guide
22
to axially extend along the guide shaft
6
. A long opening
32
is formed on a part of the small diameter section
31
facing the inclined plane
28
.
The long opening
32
corresponds to a supporting recession of the present invention. A plurality of openings is provided long in the axial direction of the guide shaft
6
and at regular intervals in the circumferential direction thereof. Housed in the long opening
32
is a lock ball
33
which is movable in the longitudinal direction within the long opening
32
. The lock ball
33
is biased to move in the direction of the arrow A by a first spring
34
and pushed against the narrowest section (i.e., the bottom) of the inclined plane
28
.
One end of the small diameter section
31
passes through the outer guide
22
to extend into a large diameter opening
35
provided on the inner periphery of the clamp base
23
. A second spring
37
is compressed between a clip
36
provided on the extended end of the small diameter section
31
and the flange section
24
to bias the clamping section
7
in the direction of the arrow B and the locking section
8
in the direction of the arrow A for relative movement.
Accordingly, in a condition shown in figure in which the locking section
8
is released, the outer guide
22
is biased to move in the direction of the arrow B by the second spring
37
. At the same time, the small diameter section
31
is biased to move in the direction of the arrow A and a lock ball
33
is biased to move in the direction of the arrow A by a first spring
34
. In this manner, the lock ball
33
is strongly pressed against the surface of the inclined plane
28
and the guide shaft
6
so that the clamping section
7
and the one way mechanism itself are locked on the guide shaft
6
. As a result, further movement of the clamping section
7
in the direction of the arrow B is prevented to be in a lock condition.
However, the movement of the clamping section
7
in such a lock condition is prevented only in the direction of the arrow B. On the contrary, the movement thereof in the direction of the arrow A is permitted. A locking mechanism of one way system is thus realized. In this case, if the locking section
8
is pulled in the direction of the arrow B against the second spring
37
, the lock ball
33
moves in the direction of the arrow B together with the smaller diameter section
31
. As a result, pressure contact of the lock ball
33
to the surface of the inclined plane
28
and the guide shaft
6
is released to make the movement of the clamping section
7
in the direction of the arrow B possible. An unlocking condition is thus realized.
Reference numeral
40
of
FIG. 3
is a center pillar for supporting a central section of the guide shaft
6
and fixedly secured onto the supporting platform
5
by bolts
41
. Reference numeral
42
is a locking shaft provided parallel to and with almost the same length as the guide shaft
6
. Each end of the locking shaft
42
is adapted to engage with a locking groove
43
(see
FIG. 1
) provided on the clamp base
23
, thereby keeping the position of the clamp pawls
10
constant.
Reference numeral
44
is a bolt for securing the supporting platform
5
onto the rotating table
4
. Reference numeral
45
is a stopper plate secured onto a central section of the base
3
by a bolt
46
to keep a ball bearing
47
provided in an upper joint between the base
3
and the rotating table
4
in position. Reference numeral
48
is a bolt for mounting the base
3
on the work bench
1
and
49
is a sliding member (i.e., a round bar) provided under the sliding table
4
.
Operation of the present invention will now be explained. As shown in
FIG. 1
, when the motorcycle engine
16
is fixedly secured onto the work bench
1
, the crank case
17
of the motorcycle engine
16
is mounted on the work bench
11
. Then, the engine hanger section
18
is inserted into the one way mechanism of which the space or interval is fully secured in advance. As shown in
FIG. 3
, the left and right clamping sections
7
are pushed to let them come closer to each other (i.e., in the direction of the arrow A) to allow the clamp pawls to engage the inside of the installation opening
19
. When let go off the clamping sections
7
at this stage, the one way mechanism is fixedly secured in this position to make the movement in the direction of the arrow B impossible and thus, the engine hanger section
18
is firmly secured in position.
When the clamp pawls
10
are disengaged from the engine hanger section
18
, if the locking section
8
is moved in the direction of the arrow B to have the unlocking condition, the clamping section
7
can be freely moved in the direction of the arrow B for disengagement. Accordingly, it is possible to provide the clamping device with a comparatively simple construction in which the clamping and unclamping operation are performed fast and easily.
In addition to the above, the position of the one way mechanism can be adjusted by a single operation and the interval between the right and left one way mechanisms can also be adjusted without restraint. Accordingly, even though the width of the engine hanger section
18
has been changed, the one way mechanism can be used in common to increase flexibility or a wide use.
Further, if the rotating table
4
is rotated by the operation of the rotating lock member
12
, it is possible to freely rotate the motorcycle engine
16
on the work bench
1
in a clamping condition and improve the workability. Still further, since the clamp base
23
is provided with the locking mechanism
43
to engage the locking shaft
42
, it is possible to move the clamp pawl
10
keeping the position constant. Thus, clamping operation can be firmly carried out.
Claims
- 1. A clamping device having a clamping section for clamping a workpiece movably provided on a cylindrical guide shaft along the axis of the guide shaft, wherein the clamping section and a locking section are each provided to make a pair at ends of the guide shaft and the locking section is fixedly secured to the clamping section in position on the guide shaft and is provided to move in a locking direction and in an unlocking direction on the guide shaft and forms a one way mechanism whereby when the locking section is moved in the locking direction, the locking section prevents movement of the clamping section only in an unclamping direction relative to the workpiece and when the locking section is moved in the unlocking direction, the locking section makes the movement of the clamping section free.
- 2. The clamping device according to claim 1, wherein the one way mechanism comprises an inclined plane formed on one side of fitting sections in which each part of the clamping section and the locking section is fitted into one another in a relatively slidable manner, a supporting recession long in the axial direction of the guide shaft formed on the other side facing the inclined plane, a lock ball housed in the supporting recession to be axially movable between the inclined plane and the guide shaft, a first spring adapted to bias the lock ball in the locking direction, and a second spring adapted to bias the locking section in the locking direction.
- 3. A clamping device mounted on a workbench, the clamping device comprising:a base fixedly secured to the workbench; a rotating table rotatably supported by the base; a supporting platform fixedly secured on the rotating table; a guide shaft which is secured to the supporting platform; and a clamping section and a locking section, each provided to make a pair on ends of the guide shaft in the axial direction.
- 4. The clamping device of claim 3, wherein the clamping section includes an arm section having a clamp pawl.
- 5. The clamping device of claim 3, wherein the rotating table includes a rotation lock member having a lock pawl which engages recessions formed on the rotating table.
- 6. The clamping device of claim 3, wherein the clamping section and the locking section move along the guide shaft along the axis of the guide shaft.
- 7. The clamping device of claim 3, wherein a stopper plate is installed at each end of the guide shaft to prevent the locking section from coming out of the guide shaft.
- 8. The clamping device of claim 3, wherein the clamping section includes a substantially cylindrical outer guide and a substantially disk-shaped clamp base.
- 9. The clamping device of claim 3, wherein the locking section includes a large diameter section and a small diameter section which engages an inner periphery of the outer guide.
- 10. The clamping device of claim 3, wherein the guide shaft includes a plurality of openings along the axial direction of the guide shaft and at regular intervals in a circumferential direction of the guide shaft.
- 11. The clamping device of claim 3, wherein an opening is formed on a small diameter section of the guide shaft, the opening including a lock ball which is movable by a first spring and pushed against the inclined plane.
- 12. The clamping device of claim 11, wherein a large diameter opening is provided on the clamp base, where a second spring is compressed between a clip provided on the small diameter section and the flange section.
- 13. The clamping device of claim 3, further including a pillar which supports the guide shaft and is fixedly secured on the supporting platform by bolts.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-351634 |
Nov 2001 |
JP |
|
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
59-169739 |
Sep 1984 |
JP |