Expansible chamber devices – With releasable stop or latch means to prevent movement of... – Includes interfitting parts engageable at plural positions...
Reexamination Certificate
2000-02-07
2001-10-30
Ryznic, John E. (Department: 3745)
Expansible chamber devices
With releasable stop or latch means to prevent movement of...
Includes interfitting parts engageable at plural positions...
Reexamination Certificate
active
06308613
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a fluid pressure cylinder having a lock mechanism capable of locking a piston rod of the fluid pressurecylinder at a necessary operational position by the lock mechanism.
PRIOR ART
As a fluid pressure cylinder having a lock mechanism for locking a piston rod at an arbitrary position, one shown in
FIG. 5
is known. According to this cylinder, a lock plate
52
fitted to a piston rod
51
is tilted around a fulcrum
59
by a biasing force of a spring
58
, thereby locking the rod
51
in a twisting manner, and the lock plate
52
is returned to a non-tilted state by supplying compressed air to a pressure chamber of the lock mechanism, thereby releasing the lock.
In the fluid pressure cylinder having such a lock mechanism, since the compressed air pressure supplied to the pressure chamber
53
is applied to the lock plate
52
when the lock is released, it is general that a piston
54
is juxtaposed with the lock plate
52
, and pressure receiving members
56
and
57
are mounted between the piston
54
and an outer peripheral surface of a sleeve
55
forming an inner peripheral wall of the pressure chamber
53
as well as between the piston
54
and an outer peripheral wall of the pressure chamber
53
, respectively.
However, in this kind of conventional fluid pressure cylinder, since the piston
54
is juxtaposed with the lock plate
52
, the entire structure is complicated. Further, since it is necessary to mount the two pressure receiving members
56
and
57
to the piston
54
, the number of parts is prone to be increased, and it needs to entail much labor for assembling the lock mechanism itself in some cases. Further, it is necessary to remove the piston
54
whenever the pressure receiving members
56
and
57
which are consumable items are exchanged, and maintenance and the like are troublesome in many cases.
Further, when the lock mechanism is assembled to a body
50
of the fluid pressure cylinder, since the compressed air is not supplied to the pressure chamber
53
, the lock plate
52
and the piston
54
are prone to be tilted. Therefore, the lock
51
is locked by the lock plate
52
and thus, it is difficult to fit the rod
51
to the lock plate
52
, and the mounting operation is not easy.
DISCLOSURE OF THE INVENTION
A technical object of the present invention is to provide a fluid pressure cylinder having a lock mechanism in which its entire structure is simple, and its assembling, maintenance and the like are easy.
Another technical object of the invention is to provide a fluid pressure cylinder having a lock mechanism in which the lock mechanism can easily be mounted to the fluid pressure cylinder.
To achieve the above object, according to a fluid pressure cylinder of the present invention, a lock mechanism for locking a piston rod in a predetermined operation position comprises an annular lock plate for locking the piston rod, a fulcrum pin for tiltably supporting the lock plate, biasing means for tilting the piston rod in its locking direction around the fulcrum pin, and returning means for returning the tilted lock plate in a lock-releasing direction. The returning means comprises a pressure chamber for introducing a pressurized fluid and a pressure receiving member comprising a single annular member which is operated by the fluid pressure for returning the lock plate. In a state where the seal of the inner peripheral end is abutted against an outer peripheral surface of the sleeve which fluid-tightly guides the piston rod and the seal of the outer peripheral end is abutted against an inner peripheral surface of the pressure chamber, the pressure receiving member is disposed such as to partition one side of the pressure chamber at a position adjacent the lock plate and is mounted to an end surface of the lock plate.
According to the fluid pressure cylinder of the present invention having the above structure, the piston rod is locked and the lock is released by supplying and discharging the pressurized fluid to and from the pressure chamber of the lock mechanism. In a state where the pressurized fluid is discharged from the pressure chamber, the lock plate is tilted around the fulcrum pin by a biasing force of the biasing means for locking the piston rod in a twisting manner. In a state where the pressurized fluid supplied to the pressure chamber, the fluid pressure is applied to the side of the pressure receiving member of the lock plate, the tilt of the lock plate is returned against the biasing force by the biasing means so that the lock of the piston rod is released.
In this case, the pressure receiving member comprising the single member for sealing the space between the lock plate and the outer peripheral surface and between the lock plate and the inner peripheral surface of the pressure chamber is mounted to the pressure chamber of the lock plate in the lock mechanism so that the fluid pressure supplied to the pressure chamber is directly applied to the lock plate. Therefore, unlike the prior art, it is unnecessary to juxtapose the piston, a plurality of pressure receiving member to be mounted to the piston are unnecessary and thus, the entire lock mechanism has an extremely simple structure and the number of parts is small,and assembling operation thereof is very easy. Further, since the pressure receiving member which is a consumable item is the single member, the exchanging operation and maintenance are easy as compared with the prior art.
In the present invention, pressure chamber which is directly applied to the lock plate and the pressure receiving members can be provided with a recess and a projection which are mutually fitted and locked, and the pressure receiving member can be connected to the lock plate by fitting the recess and projection to each other. With this structure, the pressure receiving member can be mounted and exchanged very easily.
In the invention, a body of the lock mechanism can be formed with a pin hole through which a pin for temporarily holding the lock plate in the lock-releasing position is inserted.
In this case, when the lock mechanism is mounted to the body of the fluid pressure cylinder, if the pin is inserted into the pin hole, since the lock plate can be temporarily held in the non-tilted state, the piston rod is not locked by the lock plate, and it can easily be inserted into and pulled out from the lock plate, and the mounting operation can be carried out easily.
REFERENCES:
patent: 2759569 (1956-08-01), Keehn
patent: 4015698 (1977-04-01), Sousamian et al.
patent: 4214795 (1980-07-01), Kakuminato
patent: 4700814 (1987-10-01), Mitchell
patent: 5553690 (1996-09-01), Takahashi
patent: 5823300 (1998-10-01), Higuchi
patent: 608704 (1948-09-01), None
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ryznic John E.
SMC Corporation
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