Expansible chamber devices – With guide or seal on cylinder end portion for piston or... – Non-metallic seal means between piston or member and end...
Reexamination Certificate
2001-03-07
2003-05-27
Look, Edward K. (Department: 3745)
Expansible chamber devices
With guide or seal on cylinder end portion for piston or...
Non-metallic seal means between piston or member and end...
C092S248000
Reexamination Certificate
active
06568313
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluid pressure cylinder apparatus which makes it possible to protect a sliding portion by removing minute dust or the like such as minute particles contained in a pressure fluid supplied from a pressure fluid supply source.
2. Description of the Related Art
For example, when a fluid circuit is constructed by incorporating a cylinder which is driven by the action of a pressure fluid supplied from a pressure fluid supply source, then any minute dust is generated in a fluid passage, for example, due to any deterioration of the flow passage piping of the fluid circuit, and the generated minute dust is contained in the pressure fluid in some cases.
Therefore, in the conventional technique, the pressure fluid is allowed to pass through a filter which is provided at a halfway position of the fluid passage through which the pressure fluid flows, and thus the dust in the pressure fluid is removed. On the other hand, the dust is removed at the inside of the cylinder by providing a scraper.
In the conventional technique, a cylinder is used, which is provided with, for example, a packing and a ring for holding the outer circumferential surface of a piston and the bearing portion of a piston rod in an air-tight manner.
However, in the case of the filter provided at the halfway position of the fluid passage for the pressure fluid, it is impossible to remove the dust which is generated in the fluid passage disposed downstream from the filter. Further, in a state in which the filter is deteriorated, the minute dust is not removed completely, and it arrives at respective sliding surfaces at the inside of the cylinder in some cases, because the dust passes through the deteriorated filter as well.
On the other hand, the scraper, which is provided at the inside of the cylinder, is designed such that the dust adhered to the sliding surface is swept out by means of a lip section so that the dust is removed. However, in view of its structure, for example, it is difficult to remove certain types of dust including, for example, the powder-shaped dust and the minute dust such as hair.
The piston rod, which is provided at the inside of the cylinder, has such a structure that a part of the piston rod is exposed to the outside in accordance with the displacement of the piston. Therefore, it is feared that the dust contained in the external fluid may adhere to the sliding surface of the piston rod, and the dust may enter the inside of the cylinder.
As a result, the following inconvenience arises. That is, if the dust enters the sliding surfaces of the piston of the cylinder and the bearing section for the piston rod, the sliding resistance is increased at the sliding portions of the cylinder. Further, for example, the abrasion and the deterioration of the piston packing, the rod packing, and other components are accelerated.
SUMMARY OF THE INVENTION
A general object of the present invention is to provide a fluid pressure cylinder apparatus which makes it possible to avoid any invasion of dust into respective sliding surfaces even when a pressure fluid contains the dust.
A principal object of the present invention is to provide a fluid pressure cylinder apparatus which makes it possible to avoid, for example, the increase in sliding resistance, the abrasion, and the deterioration at respective sliding surfaces by excluding the invasion of dust into the respective sliding surfaces.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.
REFERENCES:
patent: 3443486 (1969-05-01), Lanman
patent: 4086844 (1978-05-01), Homuth
Shigeo Iinuma, “Recent Trends for Pneumatic Packings,” Hydraulics & Pneumatics, 479, vol. 39, No. 6, pp. 27-38, Japan Industrial Publishing Co., Ltd. (May 1, 2000).
Fukui Chiaki
Iinuma Shigeo
Guss Paul A.
Lazo Thomas E.
Look Edward K.
SMC Kabushiki Kaisha
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