US1067770A - Two-stage compression-pump. - Google Patents

Description

G. J. SPOHRER. Two-STAGE GOMPRBssmN PUMP.

APPLICATION FILED MAR. 9L 1912.

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GREGORY JOHN SPOHRER, F FRANKLIN, PENNSYLVANA, ASSGNOR T0 WILSON MOTOR STARTER COMPANY, 0F FRANKLIN, PENNSYLVANIA.

'llO-STAGE COMPRESSIONPUMP.

Specification o1 Letters Patent.

Application filed Ilarch', 1912. Serial No. 682,583.

To all 'whom it may concern Be 1t known that l, GREGORY J. Sron'nnn,

a citizen of the United States, and a resident of Franklin, in the county of Vcnango and State of Pennsylvania, have Ainvented a C new and Improved Two-Stage Compres-4 starting mechanism, tire-intlating mechanism. etc. The pumps now on the market -are objectionable, because, among other reasons, they occupy a large amount of valuable space, and with pistons oi small diameter, especially the high pressure piston ot a small two-stage compression pump suilh cient area ot bearing cannot be obtained by the usual wrist pin or piston bearing to substantially stand the strain and wear. lt is understood in pump constructions that a low pressure cylinder must be of relatively great diameter compared with the high pressure cylinder, in order to obtain an economical ratio of compression, and in those pumps, the strokes in both the high and the low pressure cylinders are equal, the only change being made in the dia1neter of the cylinders in which the compression takes place. l l 1 I construct a two-stage compression pump particularly adapted for automobile use, in which the low pressure cylinder is more nearly equal to the dimensions otl the high pressure cylinder, and obtain the necessary ratio of cylinder volume by varying the eX- tent of reciprocation of the pistons, by positioning the pins in the crank shafts difierent distancesiirom the axis of rotation of the actuating shaft. kTo `further economize 'the space occupied by such a pump, l make the crank link relatively short and it is a desideratum in a device of this character, to shorten 'the length of the piston, but as Ithis piston must work against heavy pressure', it is necessary that it be of sufficient rigidity and size to withstand this pressure. The connections at present used in devices of this character are not adapted to form a strong` connect-ion between a relatively short piston and a relatively short link. It is advisable to have this connection positioned well within the body of the piston, and this form of connection always forms a 'feature of my invention, and in the present instance, I make use out a hellend-socket connection which gives' a firm connection in a relatively small piston, presenting more bearing surface and allowing the center of swing to be brought well up within the top of the piston. These two- ;teatures are not allowable in present forms of piston bearings, l further increase the space for bearing in the high pressure piston by shortening the relative stroke of the high to the low, thereby increasiiig the diameter oi' the high pressure cylinder and. still maintaining` the proper cylinder volume essential to two stage compressiom the whole device forming a small compact pump of high eihciency.

Reference is to be hadjto the accompany- :carentes aan is, isis.,

ing drawings, forming a 'part of this specitlcation, in which the ligure is a vertical transverse sectional view taken through a simple form 'of pump. As is general in constructions of this na ture, there is provided a shell A, the upper portion of which is formed into a low pressure cylinder B and a high pressure cylinder C, in each of which cylinders is disposed a piston D, said piston being connected byn means oit a connecting rod E to a crank F mounted in a driving shaft G, The fluid to be compressed is admitted through the inlet H and forced through the valve-covered outlet I and through the passage J into the high pressure cylinder C, ythe, piston in which cylinder, on its return stroke forces the compressed gas through the valve-con trolled outlet K. It will be noted thatfthe high pressure cylinder C is almost the diameter of the low pressure cylinder B, and, it desired, both ot' these cylinders might be ot the same volume.

The link connections with the pistons aie` relatively short, and the device is so coni structed that the pistons approach as closely as possible-'to the shaft G at one limit of their stroke, soA as to maintain the height of the pump'as small as possible. The ratio of stroke between the high and the low pressure cylinders is obtained by varying the distance of the crank pins L from the axis and the pin of the low pressurecylin-4 der. In other words, I reduce the ratio beportion of the sphere.

tween the cylinder diameters and change the ratio of the strokes of the' pistons in the cylinders, by means of a pair of unequal double cranks. The pistons in this case are substantially hollow cylinders, the compression end of each .of which is closed and the end facing the crank open. Within the open end and preferably a short distance from thecompression end, is a semi-spherical recess 2, freely revoluble in which recess is a sphere 3, extending diametrically within the vlower side of which is a screw-v threaded bore 4,v which is engaged by a reduced threaded end 5 of the connecting rod E.

In the case of the high pressure piston, the sphere 3 is retained in position by means of an exteriorly threaded sleeve 6, the upper end of which has a. spherical recess 7 adapted to. engage the under side of the sphere, said sleeve being in screw-threaded engagement with the openend of the piston. In the case of the low pressure piston, a hollow bearing block 8 may be interposed between the sleeve 6 and the s here 3. This latter construction is prefere le and is possible in the case of the low pressure piston, due to the larger size of 'this piston, thereby affording space in which to introduce this bearing block. 'It is to be'understood that the bearing block has its recess' ground to conform to` the onguration of the lower The connecting rod E projects through the sleeve 6, the opening through this sleeve being in the form of the frustum of a cone,

in order to permit the swinging of the connecting rod. Suitable packing 9 is carried by the compression end of the piston, preventing the leakage of the Huid about the piston.' L

From the construction illustrated it will ap' ear that the compression ends ofthe cylin ers B and C lie in substantiallythe same plane whereby communication from one to the other is most conveniently arranged, a fact in harmony also with the general comactness of the entire eonstuction It will e noted also that notwithstanding the dif-v ing rods E are or may be duplicates of each other, and hence interchangeable, an element of vast importance commercially. It followstherefore, because of the foregoing facts, that the lengths of the pistons from their compression ends to the centers of th'e respective balls 3 are very .different, the length of the high pressure piston being greater than the other. This provides .ample space for the ap )lication of the packing/9 thereto without interference with thel ball and socket construction. Since the strokes of the two pistons are different in extent, but being operated by the same crank shaft, the low pressure piston must o erate at a considerably hi her speed than at of the high pressure cy inder, and henc: while the low pressure piston is making its compression stroke there will be a continuous compression of the gas as it flows into the compression chamber of the high pressure cylinder, by reason of the .fact that the high pressure piston is receding therefrom at a comparatively low rate of speed. The maximum pressure therefore is had at the momentl the low pressure piston reaches its maximum compression stroke. In other words, at no time from the beginning 'ofthe compression stroke of the low pressurey piston is there any possibility of expansion of the gas vand a resulting loss of force thereof.

l'Vhile the novel elements have been described withvreference to a pump," it is, of course, to be understood thatA these new features may be utilized with obvious mechanical variations, to adapt the device to engines, 'meters, or, in fact, any place where a reciprocating member is driven from a crank shaft. e

Having thus described my invention, I claim as new and desireto secure by Letters Patent: u

l.' In a two-stage compression pump, the combination of a pair ofcylinders having a valved communication from one to the other,

pistons inthe respectivecylinders, a crank shaft, connecting rods connected to the pistons, and a pair of cranks of unequal lengths operatively connecting said connecting rods with the crank shaft whereby the -pistons are driven at different rates of speed Vand given unequal strokes.

2. The herein described `two-stage compression pump comprising a pair of cylinders extending at' their compression ends to the same plane and of different diameters, pistons of diiierent diameters fitted in said cylinders and adapted to reach said plane in their successive compression strokes, connecting rods for the pistons, the connecting rod for the larger piston being connected thereto adjacent the compression end of the piston, `and the connecting rod for the other www@ piston being connected thereto at a point remote from the compression end, a crank shaft, and means connecting the connecting rods to theshaft whereby the pistons are operatedsimultaneously lfrom said crank shaft in opposite directions at diercnt rates of speed. v

n testimony whereof have-signed my neme to this specification in the presence of two subscribing'witiicsses.

GREGORY JOHN SFOHRER. 1Witnesses:

HOMER R. BLAIR, HOLLY E. 'HOOVER

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