Expansible chamber devices – Relatively movable working members – Interconnected with common rotatable shaft
Reexamination Certificate
2002-03-27
2003-11-04
Look, Edward K. (Department: 3745)
Expansible chamber devices
Relatively movable working members
Interconnected with common rotatable shaft
C092S136000, C092S138000
Reexamination Certificate
active
06640689
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a double-rack-and-pinion swinging apparatus.
PRIOR ART
A double-rack-and-pinion swinging apparatus has merits of an increase in working torque and absorption of backlash of a gear portion at a swinging end by applying air pressure such that pistons of a pair and facing each other are actuated in opposite directions to each other.
A perspective view showing an outward appearance of a prior-art double-rack-and-pinion swinging apparatus is shown in
FIG. 3 and a
conceptual rendering showing a structure of the apparatus is shown in FIG.
4
.
In the swinging apparatus
31
, first and second cylinder bores
33
and
34
of a pair are provided in parallel in a casing
32
, first and second pistons
35
and
36
of a pair are housed for sliding in the cylinder bores, racks
35
a
and
36
a
are respectively provided to the respective pistons, and a pinion
37
is engaged with the racks. In the first cylinder bore
33
and the second cylinder bore
34
, first pressure chambers
33
a
and
34
a
and second pressure chambers
33
b
and
34
b
into and from which pressure air is supplied and discharged are formed respectively on opposite sides of the pistons
35
and
36
of the pair.
To opposite ends of the casing
32
, as shown in
FIG. 3
, end caps
41
and
42
are airtightly and detachably secured by a plurality of bolts
43
through sealing means
44
such as gaskets. Opposite ends of the cylinder bores
33
and
34
of the pair are closed with the end caps
41
and
42
. In one end cap
41
, first and second ports
45
and
46
for supplying and discharging pressure fluid to and from the pressure chambers
33
a
,
34
a
,
33
b
, and
34
b
in the first and second cylinder bores
33
and
34
are provided to directly communicate with the first pressure chambers
33
a
and
34
a.
In the casing
32
, as shown in
FIG. 4
, two air flow paths
51
and
52
respectively communicating with the first and second ports
45
and
46
are provided to axially pass through the casing
32
. In the other end cap
42
, two air flow paths
53
and
54
connected to the flow paths
51
and
52
are provided. The air flow paths
53
and
54
are formed of grooves provided to a surface of the end cap
42
and packing
55
for sealing is provided to peripheries of the grooves. The two air flow paths
53
and
54
are respectively connected to the second pressure chamber
34
b
in the second cylinder bore
34
and the second pressure chamber
33
b
in the first cylinder bore
33
.
Therefore, pressure air supplied from the first port
45
flows into the first pressure chamber
33
a
in the first cylinder bore
33
and flows into the second pressure chamber
34
b
in the second cylinder bore
34
through the flow paths
51
and
53
to drive the pistons
35
and
36
in opposite directions to each other. At this time, air in the second pressure chamber
33
b
in the first cylinder bore
33
is discharged from the second port
46
through the flow paths
54
and
52
together with air in the first pressure chamber
34
a
in the second cylinder bore
34
.
If pressure air is supplied from the second port
46
, the air flows into the first pressure chamber
34
a
in the second cylinder bore
34
and flows into the second pressure chamber
33
b
in the first cylinder bore
33
through the flow paths
52
and
54
to drive the pistons
35
and
36
in opposite directions to those in the above case. At this time, air in the second pressure chamber
34
b
in the second cylinder bore
34
is discharged from the first port
45
through the flow paths
53
and
51
together with air in the first pressure chamber
33
a
in the first cylinder bore
33
.
Therefore, the pressure air is synchronously supplied and discharged to and from opposite end portions to each other of the pistons
35
and
36
of the pair. As a result, the pistons
35
and
36
of the pair are synchronously driven in opposite directions to each other.
The swinging apparatus is used in various manners in which a swinging rotary table
49
is mounted to an output shaft of the pinion
37
engaged with the pair of racks to change an orientation of a workpiece with the table
49
or chuck arms are directly mounted to the pistons
35
and
36
of the pair to chuck the workpiece with the chuck arms.
In such a prior-art double-rack-and-pinion swinging apparatus, however, because the plurality of flow paths
51
and
52
are formed in the casing
32
to axially pass through the casing and are connected to the respective pressure chambers
33
b
and
34
b
by the flow paths
53
and
54
provided to the end cap
42
, structures of the flow paths are complicated, lengths of the holes are long, and processing for making the holes is troublesome. Moreover, because it is necessary to obtain space, thicknesses, and the like taken up by the respective flow paths
51
,
52
,
53
, and
54
in the casing
32
and the end cap
42
, the casing
32
and the end cap
42
are upsized and it is difficult to miniaturize a product.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished to solve such problems and it is technical objects of the present invention to simplify structures of air flow paths connecting respective ports and pressure chambers and to miniaturize a double-rack-and-pinion swinging apparatus.
To achieve the above objects, according to the present invention, there is provided a double-rack-and pinion apparatus comprising, a casing, a flow path forming member mounted to a bottom of the casing, a first cylinder bore and a second cylinder bore provided in parallel with each other in the casing, a first piston and a second piston for sliding in the cylinder bores, racks provided to the respective pistons and a pinion engaged with the racks, first pressure chambers and second pressure chambers formed respectively on opposite sides of the respective pistons, a first flow port and a second flow port for supplying pressure fluid to the respective pressure chambers, and a first flow path connecting the first pressure chamber on one end of the first piston and the second pressure chamber on one end of the second piston and a second flow path connecting the second pressure chamber on the other end of the first piston and the first pressure chamber on the other end of the second piston, the first and second flow paths being formed between the bottom of the casing and the flow path forming member.
In the double-rack-and-pinion swinging apparatus of the present invention having the above structure, because the first flow path connecting the first pressure chamber on one end of the first piston and the second pressure chamber on one end of the second piston and the second flow path connecting the second pressure chamber on the other end of the first piston and the first pressure chamber on the other end of the second piston are formed between the bottom of the casing and the flow path forming member mounted to the bottom, it is unnecessary to provide the air flow paths to the end cap and the long air flow paths provided to the casing and extending in the axial direction of the cylinder bores are unnecessary unlike the prior-art apparatus.
Therefore, according to the present invention, the end caps can be omitted and the long air flow paths provided to the casing and extending in the axial direction of the cylinder bores are unnecessary. As a result, structures of the flow paths of the double-rack and-pinion swinging apparatus are simple and the swinging apparatus can be miniaturized.
In the present invention, it is preferable that the first flow path and the second flow path are formed of a plurality of grooves provided to at least one of the bottom of the casing and a surface of the flow path forming member and that the grooves have packing for sealing the flow paths at peripheries of the grooves.
In the swinging apparatus, the casing includes a plurality of through holes connecting the bottom of the casing and the respective pressure chambers and the first flow path and the second flow path and the re
Hama Naoki
Magaribuchi Mitsunori
Mitsui Kaichiro
Lazo Thomas E.
Look Edward K.
SMC Corporation
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