Work holders – With fluid means – Cylinder-piston means in series with additional positioning...
Reexamination Certificate
2001-08-09
2002-05-28
Hail, III, Joseph J. (Department: 3723)
Work holders
With fluid means
Cylinder-piston means in series with additional positioning...
C269S309000, C269S038000, C074S054000, C074S409000
Reexamination Certificate
active
06394437
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clamping apparatus of such a type that pulls an output rod.
2. Explanation of Related Art
U.S. Pat. No. 4,488,713 disclosed a conventional example of the clamping apparatus of this type.
The conventional technique forms a pneumatic chamber below a piston. When clamping, it pulls an output rod through the piston with compressed air supplied to the pneumatic chamber. And when unclamping, it returns the output rod through the piston by a compression spring.
The conventional technique had a problem that it produces only a small clamping force because the compressed air which is utilized as working fluid has a low pressure.
SUMMARY OF THE INVENTION
The present invention has an object to provide a clamping apparatus which can produce a strong clamping force.
In order to accomplish the above-mentioned object, the present invention has constructed a clamping apparatus in the following manner, for example, as shown in
FIGS. 1
to
9
,
FIG. 10
or FIG.
11
.
An annular piston
20
is axially movably and hermetically inserted into a cylinder portion
13
. A first chamber
21
is formed between a first end wall
15
of the cylinder portion
13
and the piston
20
. A second chamber
22
is formed between a second end wall
16
of the cylinder portion
13
and the piston
20
. An output rod
26
is provided substantially concentrically with the piston
20
. The output rod
26
is axially movably and hermetically inserted into the second end wall
16
. Within the second chamber
22
, a first pressure receiving member
31
and a second pressure receiving member
32
axially oppose to each other in an annular space defined between the piston
20
and the output rod
26
. An annular engaging space
33
is formed between the first pressure receiving member
31
and the second pressure receiving member
32
so that it narrows radially inwards. A plurality of engaging members
34
are inserted into the engaging space
33
and spaced apart from each other peripherally at a predetermined interval. The first pressure receiving member
31
and the second pressure receiving member
32
are connected to a first end
26
a
of the output rod
26
and to the second end wall
16
, respectively. A driving means
47
provided in the first chamber
21
drives the piston
20
toward the second end wall
16
, thereby enabling a push surface
37
provided on the piston
20
to drive means the output rod
26
toward the first end wall
15
through the engaging members
34
and the first pressure receiving member
31
in the mentioned order. On the other hand, when pressurized fluid is supplied to the second chamber
22
, the pressurized fluid drives the piston
20
to return it toward the first end wall
15
and the output rod
26
to return it toward the second end wall
16
.
As for the driving: means
47
, it is considered to utilize at least one of a pressurizing force of pressurized fluid which is supplied to the first chamber
21
and an urging force of a spring
25
attached to the first chamber
21
.
Further, as for a clamp member which is connected to a second end
26
b
of the output rod
26
, it is considered to use a clamp arm
10
in
FIG. 2 and a
T-leg
7
in FIG.
11
.
The present invention functions in the following manner, for example, as shown in
FIGS. 2 and 3
.
Under an unclamping condition shown in
FIG. 2
, compressed air or the like pressurized fluid is supplied to the second chamber
22
. A pressure of the pressurized fluid moves the piston
20
toward the right which is the first end and the output rod
26
toward the left which is the second end. This moves the plurality of engaging members
34
radially outwards of the engaging space
33
and brings the first pressure receiving member
31
near the second pressure receiving member
32
.
When switching over the unclamping condition of
FIG. 2
to a clamping condition of
FIG. 3
, the pressurized fluid is discharged from the second chamber
22
and the driving means
47
moves the piston
20
toward the left which is the second end. Then the push surface
37
provided on the piston
20
moves the engaging members
34
radially inwards of the engaging space
33
. This allows the first pressure receiving member
31
and the second pressure receiving member
32
to try to strongly separate from each other in a right and left direction by a wedging action of the engaging members
34
. And the second end wall
16
of the cylinder portion
13
receives the second pressure receiving member
32
, thereby enabling the first pressure receiving member
31
to pull the output rod
26
rightwards strongly.
In consequence, the present invention offers the following effect.
A driving force added from the driving means to the piston can be force-multiplicably converted and then transmitted to the output rod through the engaging members and the first pressure receiving member. Therefore, it is possible to strongly pull the output rod. This results in the possibility of strongly clamping a metal mold or the like objects to be fixed by the clamp member such as the clamp arm or the T-leg connected to the output rod.
Besides, when unclamping, the pressurized fluid which has been supplied to the second chamber can return not only the piston but also the output rod. Accordingly, it is possible to omit a return means intended exclusively for returning the output rod. This leads to the possibility of making the clamping apparatus compact with a simple structure.
The present invention includes the following clamping apparatus.
For example, as shown in
FIG. 6
or
FIG. 9
, the engaging members
34
comprise balls, rollers or the like rolling members. In this case, it is possible to drive the engaging members smoothly by a small frictional force with the result of enhancing a transmission efficiency and eventually producing a larger clamping force.
The present invention further includes the following clamping apparatus.
For instance, as shown in
FIGS. 2 and 3
or in
FIG. 10
, the cylinder portion:
13
is fixed to a support block
6
. The support block
6
swingably supports a fulcrum portion
10
a
of a clamp arm
10
. A second end
26
b
of the output rod
26
is swingably connected to an input portion
10
c
of the clamp arm
10
. In this case, it is possible to swing the clamp arm by an axial driving force of the output rod and therefore to provide a proper clamping apparatus depending on the kind of the metal mold or the like objects to be fixed.
The present invention furthermore includes the following clamping apparatus.
For example, as shown in
FIGS. 2 and 3
or in
FIG. 10
, the cylinder portion
13
is detachably attached to the support block
6
. In this case, the support block and the cylinder portion are made as separates parts. Thus the cylinder portion can be utilized for clamping apparatuses of different, types as a common part. This results in the possibility of manufacturing those clamping apparatuses at a low cost and besides facilitating maintenance.
The present invention still includes the following clamping apparatus.
For example, as shown in
FIGS. 2 and 3
as well as in
FIGS. 4A and 4B
, the support block
6
has its lower portion provided with a T-leg
7
which engages with a T-groove
8
of a fixing pedestal
1
or a T-groove of a guide block attached to the fixing pedestal
1
. The T-leg
7
is provided with a projection
7
a
which vertically faces an output portion
10
b
of the clamp arm
10
. In this case, it is possible to vertically hold the metal mold or the like objects to be fixed: between the output portion of the clamp arm and the projection of the T-leg when clamping. This can prevent the support block from inclining by a clamp reaction force which occurs at that clamping time. In consequence, it is possible to decrease a swing angle of the clamp arm by an angle corresponding to the inclination of the support block. As a result, it is possible to reduce a stroke of the output rod and ultimately to make the clamping apparatus compact.
Hail III Joseph J.
Kabushiki Kaisha Kosmek
Shanley Daniel
LandOfFree
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