Expansible chamber devices – With linkage or transmission having relatively movable members
Reexamination Certificate
2000-06-01
2001-12-11
Ryznic, John E. (Department: 3745)
Expansible chamber devices
With linkage or transmission having relatively movable members
C092S153000, C074S605000
Reexamination Certificate
active
06327961
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable
BACKGROUND OF THE INVENTION
This invention relates to piston pumps and compressors, and more particularly to a connecting rod with an integral grease reservoir for use in piston pumps and compressors.
Small-scale air compressors are often used to power nebulizers. A typical type of compressor for that purpose uses a wobble piston. Examples of such compressors are found in U.S. Pat No. 3,961,868, issued Jun. 8, 1976 to Arthur J. Droege, Sr. et al, for “Air Compressor” and U.S. Pat. No. 4,842,498, issued Jun. 27, 1989 to Roy J. Rozek, for “Diaphragm Compressor”.
In a typical compressor, a piston reciprocates in a cylinder sleeve to compress air. The piston is a plastic connecting rod having a piston end disposed in the cylinder sleeve, and a connecting end connected to an eccentric component mounted to a shaft. As the shaft rotates, the connecting rod having a piston head disposed in a cylinder sleeve reciprocates to compress air. In one prior art compressor, the connecting rod end includes a ball bearing as the interface between the rod and the eccentric component. In another form of prior art, the rod does not include a ball bearing. Instead, a pin projecting from the eccentric component is slidably inserted into a bore formed in the connecting end. This design relies on the free rotation of the pin within the bore.
The bore is preferably formed to have an interior diameter which is substantially equal to the outside diameter of the pin to avoid chatter. Some form of lubrication is provided in this assembly to enhance the life of the bore. The lubrication method typically used includes an oil saturated felt wick that makes contact with the side of the pin, this contact occurring though a small hole in the side of the rod end. Lubrication of the bore occurs by means of capillary action drawing oil from the wick, into the bore. This design concept has proved unreliable due to problems with drying of the wick, wick becoming dislodged during operation, or poor capillary lubrication. Therefore, a need existed for a means to easily assemble and reliably lubricate the pin within the bore.
SUMMARY OF THE INVENTION
The present invention provides a connecting rod including a generally vertical oriented rod section having a piston end and a connecting end. A bore is formed in the connecting end for receiving a pin mounted eccentrically on a shaft. The bore is formed having one inside end, and a reservoir at the inside end of the bore. Since the bore diameter is substantially equal to the pin diameter, assembling the pin to the rod could be difficult due to hydrostatic pressures created from the tight fitting parts. As a means to facilitate this assembly, a bleed hole is provided in fluid communication with the inside end of the bore to provide an escape path for entrapped air. The bleed hole also provides an escape path for excess lubrication media, and is sized to inhibit an excess amount of lubrication media from escaping therethrough.
The general objective of providing a connecting rod having a bore in which a pin is easily inserted is accomplished by providing the bore with a bleed hole. The bleed hole provides an escape path for air and excess lubricant trapped in the bore during assembly.
Another objective of the present invention is to provide a connecting rod having a bore in which an excess amount of lubrication does not escape through the bleed hole. This objective is accomplished by providing a bleed hole having a diameter which is less than a diameter of the bore.
Another objective to the present invention is to provide a reservoir at the inside end of the bore for receiving and storing lubricant media, and which does not trap air therein. This objective is accomplished by providing a reservoir shaped to provide a smooth transition between the bore inside end and the bleed hole.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention.
REFERENCES:
patent: 1890550 (1932-12-01), Stenglemeir
patent: 2288596 (1942-07-01), Pierce, Jr.
patent: 2440812 (1948-05-01), Simpson
patent: 2956302 (1960-10-01), Rolph et al.
patent: 3961868 (1976-06-01), Droege, Sr. et al.
patent: 4406593 (1983-09-01), Kessler
patent: 4842498 (1989-06-01), Bramstedt et al.
patent: 4856366 (1989-08-01), Nikolaus
patent: 5213025 (1993-05-01), Rozek
patent: 5718571 (1998-02-01), Rozek
patent: 5730044 (1998-03-01), Oh
patent: 5890879 (1999-04-01), Rozek
patent: 35 05 964 C (1986-02-01), None
patent: 0 046 142 A (1982-02-01), None
patent: 98/23862 (1998-06-01), None
Quarles & Brady LLP
Ryznic John E.
Thomas Industries Inc.
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