US2875850A - Air compressor - Google Patents

Description

March 3,1959 1 w. H GLASS EI'AL 7 2,87

i AIR COMPRESSOR Filed July 19, 1955 ZSheets-Sheet l JNVENTOR. William H. G ass BY Frank W. Shirey fimeowm AT TOFQNEY Maid! 1959 ,w. H. GLASS ETAL 2,875,850

' AIR'COMPRESSOR' Filed July 1951955 1 v 2 Sheets-Sheet 2 MOUNTING anwesu TH I OIL- RESISTANT PUMP AND CASING PIC-3.2

IN V EN TOR.

Wllliam H. Glass y FranK W. Shirey United Sm Pa 4 :g-AIRCOMPRESSOR William H. Glass, Pittshurgh, and Frank W; Shirey, Irwin, Pa., assignors to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application July 19, 1955, Serial'No. 522,907

2 Claims. (Cl. 184-6) This invention relates to air and gas compressors and, more particularly, to means for lubricating the crankshaft bearings and other wearing surfaces.

Lubrication of the crankshaft bearings of an air compressor is a vital function which must be assured at all times if the compressor is to operate as intended. It is important, therefore, that the method and means for lubricating the crankshaft be dependable and readily maintainable.

Oil pumps for forcing lubricants to the bearing surfaces have been mounted in various fashions within the crankshaft casing of some compressors as, for example, on one end of the crankshaft adjacent one of the end plates of the casing. This method of mounting the oil pump, however, has proved unsatisfactory in that removal of the pump for maintenance requires removal of the end plate and entire disassembly of one end of the crankshaft.

Another method of facilitating maintenance of the oil pump consists of mounting the inlet and outlet valves in cartridge fashion so that they can be removed as a unit after an access plate has been removed from the casing. This method is also objectionable in that it is still necessary to remove the end plate and disassemble one end of the crankshaft if it is desired to service the entire pump.

Accordingly, it is one object of the invention to provide an arrangement for mounting an oil pump in air and gas compressors, whereby the pump is adapted to be mounted as a unit readily accessible for removal, maintenance and service.

Another object of the invention is to provide a novel method for mounting an oil pump within the crankcase of an air or gas compressor in such manner as to not only facilitate removal of said pump as a unit for maintenance but to also utilize the mounting of said pump to act as a vibration snubber for the crankshaft.

Other objects and advantages of the invention will become more evident from the following more detailed description thereof when read in conjunction with the accompanying drawing wherein:

Fig. 1 is an elevational view, partly in section and partly in outline, of a portion of an air compressor showing the crankshaft with the oil pump removably mounted thereon, and

Fig. 2 is an elevational view, partly in section and partly in outline, of the same portion of the air compressor, on a somewhat larger scale, taken along the line 22 and looking in the direction of the arrows.

Description and operation For illustrating the invention, the drawing shows a A bracket 16 is suspended by one end from a journal 7 centrally axially located on the crankshaft 3. A half collar 8 is secured by bolts 9 to a similarly formed and complemental portion of the bracket 6 to thereby form a surrounding collar about the journal 7 by which said bracket is suspended and in which the crankshaft 3 may freely rotate.

The opposite end of the bracket 6 supports a positivev displacement gear type pump 10, which is provided with an intake portion 11 submerged in lubricant in the oil sump constituting the bottom portion of the crankcase 1.. The pump 10 may be driven either by a pulley or sprocket arrangement comprising, for example, a sprocket 12 secured to the journal 7, as by bolts 13, for rotation with the shaft 3 and a sprocket 14 mounted on the shaft of'the' pump 10 for driving the pump gears (not shown). An endless sprocket chain 15 provides the driving connection between sprockets 12 and 14. The pump 10 is re-' siliently anchored to the bottom of the crankcase 1 by an oil-resistant rubber mounting at 16, which also acts as a snubber for dampening any vibrations of the crankshaft 3.

A passageway 17 in the bracket 6 connects the outlet side of pump 10 with a conduit 18 leading to the inlet side of an oil-filtering device 19, which, for facilitation of changing a filtering element 20, may be located at a convenient place outside the crankcase 1. A conduit 21 connects the outlet side of the filtering device 19 with a passageway 22 in the bracket 6 leading to an annular groove 23 formed internally of the collar portion of the bracket 6 adjacent the journal 7. Passageways 24 and 25 are provided in the crankshaft 3 leading to crank pins 4 and 5, respectively, whereby liquid lubricant may be distributed to the bearing surface of said crank pins.

The lubricant, which is stored in the lower portion of the crankcase 1, is taken through the inlet 11 of the pump 10 and pumped into passageway 17 to conduit 21. Should oil pressure buildup by the positive displacement pump 10 become excessive, a safety-valve device 26, comprising a spring-weighted ball check of predetermined pressure resistance, is connected to passage 17 and will open to relieve such excessive pressure into the sump.

The lubricant is forced through passageway 17 into conduit 18 and through the filter element 20 to passageway 22 through conduit 21. The lubricant is thence distributed by way of the annular groove 23 and the passageways 24 and 25 to the bearing surfaces.

Should the filter element 20 become so clogged, for example, as to prevent passage of oil therethrough, bypassing of the filtering device 19 is provided by a unidirectional by-pass valve 27 also comprising a springweighted ball check, which is set to open at a lower pressure than the safety-valve 26. Upon suflicient buildup of pressure due to the clogged element, a ball check valve 28 will be forced open against opposing force of a spring 29 to allow lubricant to flow through a passageway 30 open to conduit 18, past the ball check valve 28, through a passageway 31 leading to conduit 21 and thence to the crank pins 4 and 5, as above described.

A cover plate (not shown) may be provided for an access opening in the crankcase 1 at a convenient location thereon whereby access may be had to the pump 10 for removal and maintenance. By first removing the half-collar 8, disconnecting the conduits 18 and 21, and by disconnecting said pump at the mounting 16, the pump 10 with bracket 6 may be removed in entirety, through the access opening, for repair, replacement, or maintenance.

Having now described the invention, what we claim as new and desire to secure by Letters Patent, is:

1. In a fluid compressor, the combination comprising a crankcase, a crankshaft rotatably mounted in said crankjournal in non-rotative relation to and within said crankcase, a pump carried by said bracket, 21 sprocket carried by the said third journal of the crankshaft for rotation therewith, a second sprocket associated with said pump in driving relation, and a chain connecting said sprockets for transmitting driving force from said crankshaft to said pump through said sprockets.

2. In a fluid compressor, the combination comprising a housing, a rotatable crankshaft having two axially aligned journals, one at each end thereof, through which the crankshaft is rotatably mounted in and, supported by said housing, said crankshaft having a third journal coaxially aligned with and between said two end journals, a bracket suspended at one end from said third journal, a liquid lubricant pump carried at the other end of said bracket, 2

resilient means disposed between and connecting said pump and said housing so as to dampen vibration of said crankshaft and resiliently anchor said pump and said bracket to said housing against rotation with said crankshaft, and driving means connecting said crankshaft and said pump, said driving means being driven by said crankshaft for operating said pump to effect lubrication of said journals.

References Cited in the file of this patent UNITED STATES PATENTS 1,447,313 MacDonald Mar. 6, 1923 1,658,979 Fisher Feb. 14, 1928 1,723,945 McCutcheon Aug. '6, 1929 1,894,082 Bryan Jan. 10, 1933 2,081,157 Swenson May 25, 1937 2,590,134 Slonneger Mar. 25, 1952 FOREIGN PATENTS 6,523 Great Britain of 1907 162,485 Austria Mar. l0,v 1949 172,831 Austria Oct. 25, 1952

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