Work holders – Work-underlying support – Support mounting means
Reexamination Certificate
2002-06-04
2003-08-12
Watson, Robert C. (Department: 3723)
Work holders
Work-underlying support
Support mounting means
Reexamination Certificate
active
06604738
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clamping apparatus with a datum function and more particularly to an apparatus for accurately aligning a work pallet or the like movable member with a reference member such as a table of a machining center and fixing it thereto in such an accurately aligned state.
2. Explanation of Related Art
There is a conventional example of the clamping apparatus of this kind disclosed in Japanese Patent Public Disclosure No. 11-10468. The conventional technique is constructed as follows.
A reference member has a supporting surface formed with a fitting straight hole. A retracting nipple fixed to a movable member has a flange fitted into the straight hole. Thus the straight hole has an axis made coincident with an axis of the nipple. Thereafter, the retracting nipple is pulled, thereby fixing the movable member to the reference member.
However, the conventional technique has the following problem.
In order to smoothly attach the movable member to the reference member, it is required to provide a diametrical fitting gap between the fitting straight hole and the flange. The existence of the fitting gap decreases the aligning accuracy of the both members.
SUMMARY OF THE INVENTION
The present invention aims at making it possible to smoothly attach the movable member to the reference member and to accurately align the both members with each other.
In order to accomplish the above aim, the present invention has constructed a clamping apparatus in the following manner, for example, as shown in
FIGS. 1
to
3
or in FIG.
4
.
The clamping apparatus aligns a movable member (M) with a reference member (R) and fixes a supported surface (T) of the movable member (M) to a supporting surface (S) of the reference member (R). The supported surface (T) of the movable member (M) is opened to provide a positioning hole
12
, within which the movable member (M) is provided with a pull rod
13
substantially coaxially with the positioning hole
12
. The reference member (R) projects an annular plug portion
21
which is inserted into an annular space defined between the positioning hole
12
and the pull rod
13
. Arranged between the plug portion
21
and the positioning hole
12
is a shuttle member
23
which diametrically expands and contracts. The shuttle member
23
is supported by one of the plug portion
21
and the positioning hole
12
axially movably within a predetermined range and is able to make a tapering engagement with the other. The shuttle member
23
has a tapered surface
28
which is formed so that it narrows toward an inner portion of the positioning hole
12
. The shuttle member
23
is urged by a resilient member
24
in such a direction that the tapering engagement is made tightly. The plug portion
21
has a cylindrical hole
21
a
, into which a transmission sleeve
31
is axially movably inserted. The transmission sleeve
31
has a cylindrical hole
31
a
which can receive an engaged portion
13
b
of the pull rod
13
. The engaged portion
13
b
engages with and disengages from an engaging member
34
, which is supported by the transmission sleeve
31
. The reference member (R) is provided with a supply port
41
for cleaning fluid. A flow passage
43
,
45
is formed in at least one of a space defined between the cylindrical hole
21
a
of the plug portion
21
and an outer peripheral surface
31
b
of the transmission sleeve
31
, and a space inside the cylindrical hole
31
a
of the transmission sleeve
31
. The flow passage
43
,
45
communicates with the supply port
41
.
The present invention operates, for example, in the following manner.
When clamping the movable member to the reference member, first, the movable member automatically makes an aligning movement owing to a guiding action of the tapered surface of the shuttle member. Then the positioning hole of the movable member has its axis made accurately coincident with an axis of the plug portion of the reference member. Next, the shuttle member compresses the resilient member and it moves axially. The movable member has its supported surface received by the supporting surface of the reference member and the shuttle member is closely attached to the positioning hole and the plug portion. Thus the movable member is constrained via the shuttle member by the plug portion as well as by the supporting surface. As a result, the transmission sleeve pulls the movable member through the engaging member and the pull rod, thereby allowing the movable member to be precisely and strongly positioned and fixed to the reference member.
According to the present invention, the tapered surface of the shuttle member can make an aligning guide of the movable member, so that the movable member can be smoothly attached to the reference member. Further, differently from the above-mentioned prior art, the present invention can remove the diametrical fitting gap defined between the members to be connected. This makes it possible to align the reference member with the movable member with a high accuracy. Besides, cleaning fluid discharged from the foregoing flow passage can clean an engaging gap and a contact gap formed between the reference member and the movable member, which results in the possibility of preventing a misengagement between the both members.
The present invention includes the following clamping apparatus.
For instance, as shown in
FIGS. 1
to
3
, the shuttle member
23
has an inner peripheral surface formed by a straight surface
27
and has an outer peripheral surface defined by the tapered surface
28
. The straight surface
27
is supported by the plug portion
21
axially movably. The tapered surface
28
makes a tapering engagement with the positioning hole
12
. On an outer periphery of the plug portion
21
, the reference member (R) is formed with an annular attaching groove
29
, into which the resilient member
24
is inserted and the shuttle member
23
has its base portion fitted.
According to this invention, the reference member is equipped with the shuttle member. Therefore, in the case where a number of movable members are attached to and detached from one reference member, the equipped shuttle members are reduced in number to result in the possibility of forming a clamping system simply. In addition, the resilient member is inserted into the attaching groove and the shuttle member has its base portion fitted thereinto. This can prevent chips or the like foreign matters from invading the attaching groove. Accordingly, the shuttle member can smoothly operate over a long period of time.
The present invention further includes the following clamping apparatus.
The supply port
41
for cleaning fluid communicates with the attaching groove
29
. According to this invention, even if chips or the like foreign matters have invaded the attaching groove, the cleaning fluid can clean out the foreign matters. Therefore, the shuttle member can smoothly operate over a longer period of time.
The present invention still further includes the following clamping apparatus.
For example, as shown in
FIG. 2
, when driving the transmission sleeve
31
for unclamping, a leading end of the transmission sleeve
31
pushes at least one of the pull rod
13
and a top wall
12
a
of the positioning hole
12
. This forms an engaging gap (&agr;) on the tapered surface
28
of the shuttle member
23
and defines a contact gap (&bgr;) between the supporting surface (S) and the supported surface (T). This invention can offer an advantage that the movable member can be easily removed from the reference member owing to the existence of the engaging gap and the contact gap.
The present invention also includes the following clamping apparatus.
The pull rod
13
is supported by the movable member (M) diametrically movably within a predetermined range. In this case, when attaching the movable member to the reference member, even if the axis of the plug portion somewhat misaligns with the axis of the positioning hole, this misalignment can be absorbed by a diamet
Akin Gump Strauss Hauer & Feld L.L.P.
Kabushiki Kaisha Kosmek
Watson Robert C.
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