Work holders – Work-underlying support – Support mounting means
Reexamination Certificate
2003-01-31
2004-06-29
Watson, Robert C. (Department: 3723)
Work holders
Work-underlying support
Support mounting means
Reexamination Certificate
active
06755409
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device which automatically positions a movable member such as a work pallet to a reference member such as a table of a machine tool.
2. Explanation of Related Art
The automatic positioning device of this kind generally fits a circular positioning hole provided by opening a supported surface of a movable member onto a plug which projects from a supporting surface of a reference member (for example, see Japanese Patent Public Disclosure No. 57-27640).
The conventional technique has to provide a predetermined fitting gap between the positioning hole and the plug so as to smoothly fit the former to the latter. Therefore, the fitting gap reduces the positioning accuracy.
SUMMARY OF THE INVENTION
The present invention has an object to provide a device which can automatically perform a positioning operation with a high accuracy.
In order to accomplish the above object, the present invention has constructed an automatic positioning device in the following manner, for example, as shown in
FIGS. 1A and 1B
, in
FIGS. 4A and 4B
or in FIG.
5
.
The automatic positioning device comprises a reference member
2
having a supporting surface
2
a
which receives a supported surface
3
a
of a movable member
3
. The movable member
3
has the supported surface
3
a
opened to provide a positioning hole
5
which is formed substantially circular. A plug member
12
to be inserted into the positioning hole
5
projects from the reference member
2
in a direction to a leading end and is fixed to the reference member
2
. The plug member
12
is provided with a slant outer surface
13
which approaches an axis as it goes in the direction to the leading end. The plug member
12
has an outer periphery above which an annular intermediate member
15
is arranged so that at least peripheral one part of the intermediate member
15
radially expands and contracts. The intermediate member
15
is provided with a straight outer surface
16
which is fitted into the positioning hole
5
and with a slant inner surface
17
which opposes to the slant outer surface
13
of the plug member
12
. A pull member
21
is axially movably inserted into the plug member
12
and has a leading end portion connected to the intermediate member
15
. A locking means
31
and a releasing means
32
are provided within the reference member
2
. The locking means
31
moves the intermediate member
15
for locking in a direction to a base end through the pull member
21
. On the other hand, the releasing means
32
moves the intermediate member
15
for releasing in the direction to the leading end through the pull member
21
.
The present invention offers the following function and advantages.
When positioning the movable member to the reference member, first, the positioning hole of the movable member is fitted onto the plug member of the reference member and thereafter the locking means drives the intermediate member in the direction to the base end through the pull member. Then the slant inner surface of the intermediate member makes a wedging engagement with the slant outer surface of the plug member directly or indirectly, thereby expanding at least one part of the intermediate member radially outwards. This tightly attaches the straight outer surface of the intermediate member to the positioning hole. Simultaneously, the pull member pushes the movable member to the reference member through the tightly attached intermediate member.
On the other hand, when releasing the locked movable member, it is sufficient if the releasing means drives the intermediate member in the direction to the leading end through the pull member. Then the wedging engagement between the slant outer surface and the slant inner surface is cancelled to result in contracting at least one part of the intermediate member radially inwards. This can cancel the tightly attached condition between the straight outer surface of the intermediate member and the positioning hole. Thereafter, it is sufficient if the movable member is separated from the reference member.
The present invention can remove the fitting clearance after the positioning hole and the intermediate member have been fitted to each other. In consequence, it can smoothly fit these positioning hole and intermediate member to each other and at the same time perform the positioning operation with a high accuracy. Besides, since the locking means and the releasing means are provided within the reference member, it is possible to automatically perform the positioning operation and cancel the positioning operation and in addition to prevent chips, dust and the like foreign matters from invading interior areas of the locking means and the releasing means.
Further, at the time of the lock driving, the pull member pushes the movable member to the reference member through the intermediate member. Therefore, depending on the needs, an exclusive clamping means may be omitted.
The present invention includes the following device.
For example, as shown in
FIGS. 1A and 1B
, the intermediate member
15
comprises a thin-walled cylinder and has an annular wall
15
a
. The annular wall
15
a
has at least one part constructed so that it can elastically deform radially outwards and return radially inwards by its own elastic restoring force. The intermediate member
15
has an inner periphery provided with the slant inner surface
17
in plural number, which are spaced apart from each other peripherally at a predetermined interval. This invention can make the outer surface of the intermediate member without forming any clearance. Therefore, it can prevent chips, dust and the like foreign matters from invading a space inside the intermediate member. This makes it possible to use the positioning device for a long period of time with maintenance free.
Further, the present invention includes the following device.
For example, as shown in
FIGS. 1A and 1B
, the slant outer surface
13
is provided in plural number on the outer periphery of the plug member
12
as spaced apart from each other peripherally at a predetermined interval and a rolling member
18
is inserted into a space defined between every slant outer surface
13
and every slant inner surface
17
. This invention can engage the slant outer surface with the slant inner surface and disengage the former from the latter smoothly through the rolling member.
Moreover, the present invention includes the following device.
For example, as shown in
FIGS. 4A and 4B
, at least one slit
51
which extends axially is provided in the annular wall
15
a
of the intermediate member
15
, so that the annular wall
15
a
can elastically deform radically outwards and return radially inwards by its own elastic restoring force. This invention facilitates to process the intermediate member simply and precisely and besides can increase a radial elastic deformation amount of the intermediate member greatly.
The present invention, for example, as shown in
FIGS. 4A and 4B
, may attach rubber or the like resilient sealing member
52
to the slit
51
. In this case, the resilient sealing member can prevent foreign matters from invading the space inside the intermediate member.
The present invention, for example, as shown in
FIG. 1B
or
FIG. 4B
, includes a device wherein the intermediate member
15
is formed over its substantially entire periphery with the straight outer surface
16
. This invention can increase an area of the tight attachment between the intermediate member and the positioning hole, which results in the possibility of performing the positioning operation with a higher accuracy.
The present invention, for example, as shown in
FIG. 6
, includes a device wherein the intermediate member
15
is provided with the straight outer surface
16
in plural number as spaced apart from each other peripherally. This invention can decrease a tight attachment area of the straight outer surface to result in the possibility of securing a large press force.
Additionally, the present
Akin Gump Strauss Hauer & Feld L.L.P.
Kabushiki Kaisha Kosmek
Watson Robert C.
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