Work holders – Holder mounted for movement – With plural means for changing holder positions
Reexamination Certificate
2000-02-04
2001-06-05
Hail, III, Joseph J. (Department: 3723)
Work holders
Holder mounted for movement
With plural means for changing holder positions
C269S285000, C310S012060, C384S015000, C403S387000
Reexamination Certificate
active
06241230
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a guide apparatus having a dustproof structure (hereinlater, which may be called “dustproof guide apparatus”) for guiding a movable table or the like, and more particularly, to a dustproof guide apparatus provided with an outer (armor) cover.
FIG. 10
shows one example of a conventionally known dustproof guide apparatus utilizing a ball screw. The dustproof guide apparatus shown in
FIG. 10
comprises a screw shaft
1
supported only to be rotatable, a nut member
2
screwed to the screw shaft
1
and an outer cover
3
covering the screw shaft
1
and the nut member
2
. The outer cover
3
is formed with an upper opening
4
, in an illustrated state, in parallel to the screw shaft
1
. The nut member
2
is integrally formed with a movable member
5
, which is secured to a member to be guided, in a manner such that the movable member
5
is moved linearly along the opening in accordance with the rotation of the screw shaft
1
. The opening
4
of the outer cover
3
is covered by a seal member
6
made of rubber, and the seal member
6
is formed with one linear cut (cut line)
6
a
along the screw shaft
1
. The movable member
5
forcibly bents outward the seal member
6
along the cut line
6
a
so as to project outward through an opening O formed by forcibly bending the seal member
6
. The movable member
6
carries out a linear reciprocal motion along the cut line
6
a
while widening both sides of the cut line
6
a
of the seal member
6
. According to this structure, dust or the like generated from the ball screw can be prevented from being discharged outward by covering the screw shaft
1
and the nut member
2
by the outer cover
3
and the seal member
6
.
However, in the structure of the dustproof guide apparatus shown in
FIG. 1
in which the linear cut
6
a
is formed to the seal member
6
, a gap having a slight width will appear between portions
6
b
and
6
c
of the seal member
6
facing each other along the cut line
6
a
, and the width of this gap will be gradually widened while the movable member
5
being reciprocally moved repeatedly, which provides a problem such that dust or the like is discharged through such widened gap outward the outer cover
3
. Thus, according to the structure of the conventional dustproof guide apparatus such as shown in
FIG. 10
, it is difficult to achieve high dustproof property.
SUMMARY OF THE INVENTION
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a guide apparatus having dustproof structure capable of achieving high dustproof performance.
This and other objects can be achieved according to the present invention by providing, in a broader aspect, a guide apparatus having a dustproof structure comprising:
a linear guide device;
an outer cover mounted to the linear guide device so as to cover the linear guide device and provided with an opening, said linear guide device including a movable member having a portion projecting outward through the opening formed to the outer cover, the movable member being movable along the opening; and
a sealing structure having a plurality of seal members each in shape of belt and having flexibility, the seal members being applied to edge portions of the opening of the outer cover so as to be overlapped to each other thereby to substantially keep a sealed state inside the linear guide device.
In preferred embodiments of this aspect, the movable member has a guide structure provided with a sharp end portion to separate and push aside the overlapped seal members in accordance with an advancing motion of the movable member, the guide structure being provided with a side portion gradually widened outward in a direction reverse to the advancing direction of the movable member.
The guide structure is formed integrally with the movable member or formed as a member independent from the movable member.
The movable member is provided with a closing member for closing the opening of the seal members.
A sliding surface between the guide structure and the sealing structure is formed with a protrusion extending continuously in a longitudinal direction thereof.
According to the structures of the present invention of this aspect, the following advantageous effects or functions will be attained as well as achieving the above object.
Since the seal members have overlapped end portions, any gap is not formed between the respective seal members thereby to completely keep the inside of the outer cover, i.e. the linear guide device. The movable member is moved so as to forcibly push aside and open the seal members, and the seal members are then returned to their original shapes because of their own flexible or elastic property. That is, according to the structure of the guide apparatus of the present invention, the seal members are only opened at the portions at which the movable member is passing and portions of the seal members other than these portions are completely closed during the advancing motion of the movable member, thus realizing the guide apparatus having high dustproof structure.
Furthermore, according to the preferred embodiments, the seal members are gently deformed by the guide structure at the time of the reciprocal motion of the movable member, and after passing the movable member, the seal members are gently closed in the original closing state, thus surely preventing a gap between the guide structure and the seal members from causing.
By separately, i.e. independently forming the guide structure, relatively complicated guide structure can be easily manufactured, thus easily manufacturing the movable member itself.
In a case where the movable member carries out the repeated reciprocal motions, there may cause a case that the seal members maintain the bent shapes and are not completely returned to their original shapes. According to the present invention, such bent portions of the seal members are forcibly pressed inward by the closing member such as rod-shaped pins, whereby the seal members can be more surely closed after the passing of the movable member.
Furthermore, the location of the continuous protrusions of the sliding surface can reduce the friction resistance between the guide structure and the seal structure, thus smoothly performing the linear motion of the movable member.
In another aspect of the present invention, there is provided a guide apparatus having a dustproof structure comprising:
a linear guide device generally having a
-shaped cross section having an opening;
an outer cover mounted to the linear guide device so as to cover the opening of the
-shaped guide device and provided with an opening, the linear guide device including a movable member and a linear member along which the movable member is reciprocally moved, the movable member having a portion projecting outward through an opening formed between the outer cover and the linear guide device to be movable along the opening formed between the outer cover and the linear guide device; and
a sealing structure having a plurality of seal members each in shape of belt and having flexibility, the seal members being applied to edge portions of the opening formed between the outer cover and the linear guide device so as to be overlapped to each other thereby to cover the opening between the outer cover and the linear guide device and substantially keep a sealed state inside the linear guide device.
In preferred embodiments of this aspect, the movable member comprises a movable body, side portions formed as the projections on both sides of the movable member and coupling portions through which the movable body and the side portions are connected to each other, the coupling portions being positioned in a level corresponding to the overlapped portions of the seal members.
The coupling portions have sharp end portions in the moving direction of the movable member.
The coupling portions may be formed with guide pieces at both end portions thereof along the moving direct
Hail III Joseph J.
Shanley Daniel
THK Co., Ltd
Young & Thompson
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