US2572711A - Air compressor - Google Patents

Description

W. V. FISCHER AIR COMPRESSOR Oct. 23, 1951 3 Sheets-Sheet 1 Filed March 27, 1945 INVENTOR. VV/LL/A M V FscHER i? rj/w ATTORNEYS w. 'v. FISCHER AIR COMPRESSOR Oct. 23, 1951 3 Sheets-Sheet 2 Filed March 27, 1945 INVENTOR VV/LL/AM M Hie/15R Mia/7 WM A TTORNEY;

W. V. FISCH ER AIR COMPRESSOR Oct. 23, 1951 5 Sheets-Sheet 15 Filed March 27, 1945 INVENTOR. WLL/AM V. HSCHER n ,9 'A ilfiaz I TORNEYS iatentecl Oct. 23, 1951 QF IGE asiznn Ara COMPRESSOR William V. Fischer, Akron, Ohio, assig nor to M. Fischer A Application March 27, 1945, Serial No. 585,118

This invention relates broadly to air come pressors and more particularly to improvements in the construction of certain of the parts embodied. therein.

One of the objects of this invention is to, provide a compressor crankcase adapted to receive either two, four, six or eight cylinders of iden-' tical form and to provide a mechanism for varying' the reciprocative movement of the pistons in said cylinders.

Another object is realized by a structure which will accommodate the interchangeability of the parts of the compressor and the ready conversion of the machine from one size to another.

Another object resides in the economies real ized by the purchaser of a small compressor who may later wish to buy additive parts to enlarge the capacity of his machine." A' further object resides in the economies realizedby the manufacturer of compressors who may construct a large-number of various size machines from a limited number of interchangeable or s u bstil'iu' tion parts.

Other objects and advantages more or less ancillary to the foregoing and the manner 'in which all the various objects are realized-willappear in the following description, which considered in connection with the accompanying drawings, sets'forth the preferred embodiment of the invention.

Referring to the drawings:

Fig. l is a longitudinal sectional view of the improved air compressor havingtwd cylinders mounted vertically on the crankcase;

Fig. 2 is a transverse section through the compressor illustrating the organization of parts to form a six cylinder compressor;

Fig. 3 is a view similar to Fig. 2 showing the addition of two cylinders and the reorganization of certain parts thereon to form-an eight" cylinder compressor;

Fig. 4 is an elevational view of one of the crankcase end plates illustrating the eccentricity of the bearings therein;

Fig. 5 is an isometric viewof the improved crankcase;

Fig. 6 is a transverse section on line fi6 of Fig. 1;

Fig. '7 is a transverse sectional view through the four cylinder modification;

Fig. 8 is a view upon an enlarged scale of one of the connecting rods; and

Fig. 9 is a view similar to Fig. 8. showing different adjustments of the eccentricbnshings.

. Referring first to Figs. 2' and 5; thecrankcase 14 Qlai n s, (Cl. 23020) ID is formed with a semi-cylindrical upper portion having transverse parallel slots ll therethrough for the reception of banks ofrradially disposed cylinders l5 Recessedseats 12 adja: Cent he ou daries .ofsaid slot provide hearing surfaces for the support of saidgcylinders. the flanges l6 thereof being of arcuate form and rectangular outline to conform to said Seats; "The cylindrical portions of theseats 12 are provided with T-slots 13 having openings [5.111 the ends thereof for the reception of the headset the cylinder bolt 11.

As shown in Fig. 3, the slots I l and the cylinder flanges l5 are proportioned to accommodate the ea e e a ement of four contiguous radial y disposed cylinders, each being inclined at an angle of 45 degrees relative to the adjacent cyl inder. Two diametrically opposed circular eccentrics or cams l8 are keyed on a drive shaft E9 in alignment with the centers of the banks ofcylinders 15. Connectingrod straps 20 having integral or master connecting JrodsZl. for'tlie support ofpistons 25 are .journa-ll'ed upon the circumferential faces of the eccentrics. Themaster rods 2| also function'to delimitthe ro-I tation of thestraps 20 about the eccentrics l3. The connecting rod straps 2B are formed with a plurality of aperturedbosses 23. (Fig. 6') disposed at 45, and degree angles relative to themaster rods 2|, for the support of connectingrods 22, which operate respectively, in cylinders disposed in corresponding "angular relation with the cylinders for the master rods.

Referring to the six cylinder machine in Fig. 2, it will be noted that'coverplates 24 are use'd' as spacers to properly position the cylinders in 6.0 degree relationship and are also used to close the openings between the. cylinder flanges. vThe cover plates are securedto thencrankcase by bolts 11 similar to cylinder bolts and retained in a like manner by the shoulders in the :r-slots I13.

From a comparison of Figs. 2,," 3, 6 and-.7 it will be readily noted that the operation of changing.

the machine to form a two, four, .si'x .oreight cylinder compressor'is easily accomplished. Access to the interior of the crankcase for the reorganization of the parts therein is attained v.by' removing the end plates .25 (Fig.1). *Th'ecover plates 24 are then removed frornthe slots 1!, and the desired-number of cylinders are installed thereon and circumferentially' spaced by the use of another set ofcover plates. Elliemaster connecting rods 2| operate inthe'vertical cyl inders in the two or six cylinder compressors and inthe uppermost cylinders in .the'four or eight cylinder machines. The necessary number ofarticulative rods 22 are secured topistons 26 and to theapertured bosses 23 of angular displacement from themaster rods 2| corresponding to the angles between the cylinders which house the rods.

The eccentrics is are formed with threedrive shaft holes 21 of varying eccentricity providing three adjustments of the length of stroke. Any one of the holes may be used with any of the cylinder groups as heretofore described, by making further adjustments of parts to proportion the size of the compression chambers to the stroke length. For this purpose thevalve plates 28 are designed for reversible assembly between the cylinders I and thecylinder heads 29. One side of said plates is a plane surface having a shallow annular depression therein for intimate engagement with either a conforming annular protuberance on the inner surface of the cylinder heads 29 (Fig. 2) or alternatively with the upper end of the cylinders I5 (Fig. 3). The opposite sides of the valve plates are formed with cylindrical bosses for snug engagement within the inner walls of the cylinders I5, the compression chambers thereof being diminished by an amount equal to the volume of said bosses. Thus the volumetric delivery of a compressor of any fixed cylinder group may be reduced by inverting the valve plates and changing the drive shaft hole to shorten the stroke.

The stroke may be further shortened by utilizing the third hole in the eccentrics l8, and by elevating the drive shaft A to effect a corresponding reduction of the compression chambers. shown in Fig. 4, thebearings 30 for the support of said drive shaft in thecrankcase end plates 25 are eccentric on the vertical center line of the plates; therefore, rotation of the end plates through 180 degrees will raise or lower the drive shaft a distance equal to twice the eccentricity ofthebearings 30.

This elevation of the drive shaft reduces the compression chambers of the vertical cylinders to correspond to the reduced stroke effectuated by the use of the third hole in the eccentrics I8. The'compression chambers of the oblique cylinders, however, are not diminished to the same degree, the diminution being greater in the more vertical cylinders. To obviate this unbalance of compression in the various cylinders, the connecting rods are provided with eccentric bushings 3| adapted upon rotative adjustment to change the center to center distance between thepiston pins 32 and the rod bearing-pins 33. The bushings are adjusted and locked against rotation by set screws which engage index holes in the outer surface thereof. Referring to Fig. 8, the bushings 3| are shown in their normal adjustment for use with the drive'shaft in its lower position. The dimension A on this figure is the normal center to center distance between the piston pins and the rod bearing pins. Fig. 9 illustrates the adjustment of the bushings and the increased pin center to center distance B which are used in the lower cylinders of the eight cylinder machine. In the eight cylinder compressor illustrated in Fig. 3, the drive shaft I8 is elevated by rotating thecrankcase end plates 25 through 180 degrees, and the compression chambers of the oblique cylinders are reduced to the same size by different adjustments of the bushings 3 I. In this compensative adjustment the bushings in the lower connecting rods extend the pin center to center distance by an amount approximately three times the extension in the upper cylinder chambers of all the cylinders.

From the foregoing it will readily be perceived that with this compressor four different cylinder combinations, each having three stroke adjustments, may be produced using the same basic parts and a variable number of identical cylinder assemblies. The two cams I8 of opposite action provide an even timing or compression strokes throughout each revolution in any of the various arrangements heretofore described.

When it is desired to efiectuate two stage com pression, a long stroke is used in one bank of cylinders which constitutes the first stage; and the output therefrom is connected to the inlet of the second bank of cylinders. The stroke in said second bank is reduced, and the air in the cylinders is under pressure at the beginning of the compression stroke; thus the second bank of cylinders functions as the second stage of a twostage compressor.

The advantages of a compressor pump of this nature are manifold. The purchaser may, by merely reorganizing the various parts of his compressor; change to any of three output rates. By the purchase of additional cylinder assemblies, 1. e. cylinders, pistons, rods and bushings, the machine may be easily converted to a higher volumetric delivery. The multiplicity of adjustments of output rate makes possible the operation of the compressor at the most efficient speed and makes unnecessary the common practice of increasing the speed of operation of a compressor beyond the safe limits thereof for enlarging the output rate.

The manufacturer of this type compressor receives the benefit of substantial savings in tool and pattern costs, savings in the manufacturing cost consequent mass production of standardized parts and the reduced sales resistance resulting from his ability to offer multi-size machines formed from sub-assemblies of interchangeable parts.

Although the foregoing description is necessarily of a detailed character, in order that the invention may be completely set forth, it is to be understood that the specific-terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modifications of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed. 7 s

I claim:

1. A compressor embodying a crankcase, a plurality of cylinders mounted for adjustment thereon, pistons in said cylinders, a drive shaft in said crankcase, circular eccentrics keyed thereon, straps journalled on said eccentrics, connecting rods on said straps for the operative support of said pistons, means in said eccentrics for varying the lift thereof, valve plates on said cylinders the two faces of the said valve plates being asymmetrically disposed with respect to the mounting surfaces of the valve plates whereby inverting the valve plates will compensate the variations in the lift of said eccentrics, a semi-cylindrical surface on said crankcase having transversepar allel slots therethrough for the connecting rods, and means in the walls of said crankcase adja-' cent said slots for the securement of said cylinders in operative relation to said eccentrics and connecting rods.

2. In a compressor embodying a drive shaft, connecting rods and pistons,a crankcase therefor of substantially semi-cylindrical form having transverseparallel elongated openingstherein, a plurality of radially d-is'posed cylinders mounted on said crankcase and provided with cylinder flanges of arcuatetransverse section and rectangular outline spanning said openings, b'olts in,

said flanges, recessed seats in the walls or said crankcase adjacent said openings having T-slots therein for the retention of said cylinder bolts the openings providing for comin unication between the crankcase and cylinders.-

3.. A compressor embodying a crankcase of substantially semi-cylindrical configuration, a plurality' of identical cylinders mounted thereon, pistons in said cylinders, a drive shaft in said crankcase, mechanism associated therewith for operating said pistons in said cylinders; curved flanges on said cylinders for engagement with said crankcase, said crankcase'liav'ing openings therein disposed in spaced parallel relationfor said piston operating mechanism, means for mountingsaid cylinders over said openings in spaced relation, in various positions longitudinally of the openings, and cover plates over the portions of the openings intermediate said cylinders, whereby either two, four, siX or eight cylinders may be operatively assembled on said crankcase.

4. A compressor comprising a crankcase, cylinders thereon; curved flanges on said cylinders, pistons in said cylinders, a' transversely curved upper portion on said crankcase having; parallel slots therein, ledges adjacent the edges of said slots for the seated engagement of said curved flanges, a drive shaft in said 'crankcaseieccentric cams keyed thereon; connecting rod straps journalled on said cams, apertured bosses on said straps, articulative connecting rods passing through said slots and engagedwith said bosses, pins for the securement of said rods-0nsaid bosses and on said pistons, means for theselective adjustment of the effective length of said rods, means in the eccentric cams for changing the length of stroke of said pistons, valve plates contiguous the outer ends of said cylinders, said plates being bilaterally asymmetrical and adapted for invertible mounting upon the cylinders to vary the depth of the compression chambers in said cylinders, end plates in said crankcase, and bearings therein for the said drive shaft eccentrically disposed on the vertical center lines of said end lates, whereby the volumetric delivery of said compressor may be varied.

5. A compressor comprising a plurality of cylinders, arcuate flanges thereon, pistons in said cylinders, a drive shaft, mechanism intermediate said pistons and said drive shaft for operating said pistons, a crankcase formed with a wall of arcuate form having an opening therein, ledges in said wall having fastener-retaining grooves, means in said flanges cooperating with the grooves in said ledges for the securement of said cylinders on said crankcase over said opening in variable angularly spaced relation with each other the said opening being provided to accommodate said intermediate mechanism.

6. A compressor comprising cylinders, flanges thereon of cylindrical form, a crankcase partly of cylindrical form having a circumferential cylinder-receiving opening in the cylindrical portion thereof, a drive shaft in said crankcase, pistons in said cylinders, means associated with said drive shaft passing through said opening for reciprocating said pistons, means intermediate said pistons and said drive shaft for varying the reciprocative movement ofs aid piste in said cylinder flanges for the see the cylinders upon said cylinder feceivm s P ing in various circumferential positions leisure to said drive shaft. Q

7 A: compressor embodying a'crankcase, a-plurality of cylinders adapted to be mounted thereon, pistons in said cylinders, a drive shaftsaid crankcase, means operated by the sai drive sh ft for reciprocating the pistonsincl'u for varying the pistonstroke, and inveram' va'lv e plates at the head or said cylinders; thasaid valve plates-being 'soasymmetrical-Ty 'co figured that inversion thereof alters the'size of the c'orh pr'essionchambers in said cylinders; 4 W

8. In a compressor embodying adri've' shaft, connecting rods, and pistons, a crankcase" there for of substantially semi-cylindrical forfn' having an elongatedopening disposed circumferentia of the cylindrical portion thereof, a plurality of cylinders adapted tdb'e mounted on said'crahkcase and disposed radially therefrom, the eye inders being provided with flanges of arcuate transverse section adapted to span said opening, means'fcr securing said flanges to-saidc'rankcase over said opening with spaces between adjacent flanges, and means for closing the portions of said opening between the cylinder flanges.- H

9. A compressor comprising a: cran cas inders thereon; curved flanges on saidcyliri pistons in said cylinders, a transverselycu fed upper portion on said crankcase having parallel slots therein, ledges adjacent the" edgesr said slots for the seated engagement of saidcur' flanges, a drive shaft in said crankcase; 'eccen cams keyed thereon, connecting rod straps your: nailed on said cams, apertured bosses on; said straps, articulative connecting rods engaged with said bosses and passing through said slots, pins for the secure'm'ent of said rods on said-basses and on said; pistons, means for thes'elective'ad' j'us'tm'ent' of the effective length of said reds, and means in the eccentric cams for changing the length of stroke of said pistons.

10. A compressor comprising a crankcase, cylinders thereon, curved flanges on said cylinders, cylinder bolts in said flanges, pistons in said cylinders, a transversely curved upper portion on said crankcase having parallel slots therein, ledges adjacent the edges of said slots for the seated engagement of said curved flanges, a drive shaft in said crankcase, eccentric cams keyed thereon, connecting rod straps journalled on said cams, apertured bosses on said straps, articulative connecting rods engaged with said bosses, pins for the securement of said rods on said bosses and on said pistons, means for the selective acl= justment of the effective length of said rods, means in the eccentric cams for changing the length of stroke of said pistons, end plates in said crankcase, and bearings for the said drive shaft therein eccentrically disposed on the vertical center lines of said end plates, whereby the volumetric delivery of said compressor may be varied.

11. A compressor comprising a crankcase, a portion of the crankcase being of the form of a portion of a surface of revolution about an axis, and formed with an elongated opening circumferentially of the said portion; cylinders formed with an open end and a flange complementary in form to the said surface, the opening being sufiiciently long to accommodate at least two cylinders; means for securing the cylinder flanges to the crankcase at any position longitudinally of the opening with the open end of the cylinder aligned with the opening; pistons in the cylinders; a crankshaft in the crankcase; and means connecting the pistons and crankshaft for reciprocation of the pistons.

. 12. A compressor comprising a crankcase, a portion of the crankcase being of the form of a portion of a cylinder and formed with an elongated opening circumferentially of the said portion; cylinders formed with an open end and a flange complementary in form to the said cylindrical surface, the opening being sufliciently long to accommodate at least two cylinders; means for securing the cylinder flanges to the crankcase at any position longitudinally of the opening with the open end of the cylinder aligned with the opening; pistons in the cylinders; a crankshaft in thecrankcase; and means connecting the pistons and crankshaft for reciprocation of the pistons.

13. A compressor comprising a crankcase, a portion of the crankcase being of the form of a portion of a surface of revolution about an axis, and formed with an elongated opening circumferentially of the said portion; cylinders formed with an open end and a flange complementary in form to the said surface, the opening being sufiie ciently long to accommodate at least two cylin ders, and the size of the openings between the cylinders being dependent upon the number of cylinders employed; means for securing the cylinder flanges to the crankcase at any position longitudinally of the opening with the open end of the cylinder aligned with the opening; cover plates complementary in form to the said surface and the adjacent edges of the said flanges and adapted to close the opening between the flanges; means for securing the cover plates to the crankcase; pistons in the cylinders; a crankshaft in the crankcase; and means connectin the pistons and crankshaft for reciprocation of the pistons.

14. A compressor comprising a crankcase, a

portion of the crankcase being of the form of a portion of a surface of revolution about an axis, and formed with elongated openings circumferentially of the said portion; cylinders formed with an open end and a flange adjacent the open end complementary in form to the said surface, the openings being sufliciently long to accommodate at least two cylinders, and the size of the openings between the cylinders being, dependent upon the number of cylinders employed; means for ecuring the cylinder flanges to the crankcase at any position longitudinally of the openings with the open end of the cylinder aligned with the opening; cover plates complementary in form to the said surface and the adjacent edges of the said flanges and adapted to close the opening between the flanges; means for securing the cover plates to the crankcase; pistons in the cylinders; a crankshaft in the crankcase; and means connecting the pistons and crankshaft for reciprocation of the pistons.

WILLIAM V. FISCHER.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS Number Name Date 764,573 Furru July 12, 1904 1,639,333 Ford Aug. 16, 1927 1,744,775 Lindsay Jan. 28, 1930 1,846,655 Rayfield Feb. 23, 1932 1,989,117 Svenson Jan. 29, 1935 2,255,852 Lundin Sept. 16, 1941 2,263,786 Rumpp Nov. 25, 1941 FOREIGN PATENTS Number Country Date 119,356 Great Britain 1918 177,225 Great Britain Mar. 17, 1922 373,565 France 'Mar. 31, 1907

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