Expansible chamber devices – With inspection window in expansible chamber wall portion – With lock
Reexamination Certificate
1998-11-30
2001-04-24
Look, Edward K. (Department: 3745)
Expansible chamber devices
With inspection window in expansible chamber wall portion
With lock
C092S106000
Reexamination Certificate
active
06220143
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary cylinder device for controlling operations of a chuck to be used on a lathe or the like.
2. Description of the Related Art
Generally, a rotary cylinder device is constructed by fitting a piston axially sidably in a cylinder unit, supporting the cylinder unit for rotation in a bearing on a distributor, and fitting the distributor in an annular draining space formed in a housing. A rotary cylinder device disclosed in JP-B-63-41689 (reference 1) has a distributor positioned and held fixedly in place in an annular space with a bolt screwed in a housing so that its tip is pressed against the distributor. Another rotary cylinder device disclosed in JP-A-61-241505 (reference 2) has a distributor held fixedly in place in an annular space with a bolt screwed in a housing so that its free end part is fitted in a radial hole formed in the distributor.
Vibrations may be generated in those prior art rotary cylinder devices if the distributor makes a slight turning movement in a direction opposite to a direction in which the cylinder unit rotates at a high rotational speed. Therefore, the distributor is fastened to the housing with the bolt as mentioned in the references 1 and 2. In the reference 1, the bolt is pressed against a part of the distributor separated from an annular groove, such as an oil passage, formed in the distributor and hence the bolt is pressed unavoidably against a part of the distributor near the bearing. Consequently, it is possible that the bearing is distorted by pressure exerted on the distributor by the bolt. In the reference 2, if foreign matters are caught in the thin annular space between the distributor and the cylinder unit and cause seizure between the distributor and the cylinder unit, the distributor is forced to rotate together with the cylinder unit. Therefore, it is possible that the torque of the cylinder unit is transmitted through the distributor and the bolt to the housing and the housing is forced to rotate together with a high-pressure hose connected thereto.
Seizure between the cylinder unit and the distributor can be known from the excessive rise of load on the spindle motor of a lathe or the like. However, the excessive load that may be produced by seizure between the cylinder unit and the distributor and may be exerted on the spindle motor must be greater than a load corresponding to a cutting force necessary for machining. Therefore, the rotary cylinder device may be damaged seriously and troubles will occur before seizure between the cylinder unit and the distributor is detected.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a rotary cylinder device comprising a housing, a cylinder unit, and a distributor supporting the cylinder unit in bearings fitted therein and capable of being fixedly held on the housing without distorting the bearings supporting the cylinder unit and of being disconnected from the housing when seizure occurs between the distributor and the cylinder unit.
Another object of the present invention is to provide a rotary cylinder device comprising a cylinder unit, a distributor, and a seizure detecting means for detecting seizure between the cylinder unit and the distributor.
According to the present invention, a rotary cylinder device comprises: a cylinder unit having a distributor support member and a piston chamber therein, and a piston axially slidably fitted in the piston chamber; a distributor supported for rotation on a support part of the distributor support member; and a housing defining an annular draining space and provided with a side wall defining a bore closely receiving the distributor therein; and a detaining mechanism for restraining the distributor from rotation relative to the housing, said detaining mechanism including a protrusion provided for one of the housing and the distributor, and a recess provided in the other of the housing and the distributor and tightly receiving the protrusion, said protrusion being adapted to be forced to move out of the recess to allow the rotation of the distributor relative to the housing when a torque exceeding a threshold torque is exerted on the distributor.
The rotary cylinder device may further comprise a seizure detecting system capable of detecting the rotation of the distributor together with the cylinder unit due to seizure or the like.
The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings.
REFERENCES:
patent: 4040338 (1977-08-01), Wilson et al.
patent: 4996908 (1991-03-01), Thompson
patent: 61-241505 (1986-10-01), None
patent: 63-41689 (1988-08-01), None
Howa Machinery Ltd.
Ladas & Parry
Lazo Thomas E.
Look Edward K.
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