US2102389A - Valve mechanism - Google Patents

Description

A. C. STALEY VALVE MECHANISM Dec. 14, 1937.

N V EN TOR. 671621 a szdz Patented Dec. 14, 1937 UNITED STATES PATENT OFFICE Chrysler Corporation, Highland Park, Mich, a corporation of Delaware Original application July 28, 1932,, Serial, No. 625,449, now Patent N 0. 2,011,780, dated August 20,- 1935. Divided and this application March 30, 1935, Serial No. 13,823

4 Claims.

My invention relates to or gas expanding mechanism of the reciprocating piston type and has particular relation to several novel types of valve mechanism, and several novel combinations of such types, for use in equipment of the character designated, and is a division of my copending application Serial No. 625,449, filed July 28, 1932,- which has now issued as Patent No. 2,011,780, dated August 20, I935.

More particularly, my invention relates to novel types of inlet and exhaust valve mechanism, and to novel combinations thereof for use in air or gas expanding'mechanism for use in refrigerating systems.

By my invention, I have provided a mechanically operated valve of the poppet type for use as an intake valve in an air motor in which a cam of normal contour is employed to operate the valve and "in which the valve ismechanically closed at the proper time, thus eliminating both of the objections of the aforementioned type of valve.

One of the objects of my invention consists in providing a novel typeof valve adapted forum as "an exhaust valve of air motorsof the'reciproeating type which eliminates the objections of both the mechanically operated and thepressure operated valve and retains the advantages of both types.

Another object of my invention is to provide ano'vel type of intake valve for air motors and expanding machines of the' reciprocating type thateliminates the objections to, and retains the advantages of; mechanically operated valves.

A still further object of my invention consists in providing a novel type of valve mechanism in which the effect of the inertia of the? valve closing'memberis eliminated asa factor in the timing of op'eration' of pneumatically operatedvalves.

An additional object is to provide a combination of intake and exhaust valve mechanism for use in air moto-rs or in expanding machines as used in refrigerator equipment.

For a more'detailed understanding of my invention reference maynow be had to the accompanying drawings, of which:

Fig. 1 is a longitudinal cross-sectional view of a combined compressor and expander, or air motor, constructed in accordance with my inven-' tion and adapted for use in refrigeration systems.

Fig. 2 is a transverse cross-sectional view of the structure illustrated in 1, the section being taken along the'lin II- II thereof.

Fig: 3 is a fragmentary'transverse cross sectionalview takeii along the line III-III of Fig. 1.

Fig. 4' is a horizontal sectional view taken on the line IV-IV of Fig. 3, I t

In Fig. 1 is illustrated a combination gas or air compressing and expanding machine adapted particularly for use in a refrigerating system. In this construction, a crankshaft operates two compressor pistons 16 and has connected thereto twoexpandingmachine or air motor pistons H. v The two pistons 16 move within com pressor cylinders 18 which are of larger diameter than the expander or air motor cylinder 19 within which the pistons 11 operate. The compressor cylinders 18 are each provided with an intake valve mechanismlifl similar to that illustrated in Fig. 2, and an exhaust valve mechanism 8!,siniilar to that illustrated in Fig.3. The expander or air motor cylinders are each provided with an intake valve mechanism 32, similar to that illustrated in Fig. 3, and an exhaust valve mechanism 33', similar to that illustrated in Fig. 2. v

The valve mechanisms 80, 8|, 82 and 83 are operated by valve operating rods [8 and I9 which in turn are operatedby acain shaft 20 provided with four inlet valve operating cams'Zland the same number of similar exhaust valve operating cams (not shown). The cam shaft 20 is driven athalf thespeed of the crankshaft by means of the gear 23"se'cured thereon which mesheswith a smaller gear 24 mounted on the crankshaft.

Iri refrigerating systems of this type, it is customary toemplo'y a, compressor or compressor cylinder which serves to compress air or other gas, preferably the former, which compressed gas is then carried to an air cooling means, such as a water or air cooled radiator or the like. The

compressed gas, now cooled, is in turn admitted to the expander or air motor which reduces the pressure thereof, and the cold airat the reduced pressure is then conducted to the chamber to'he cooled; such as arefrigerating"chamber, room, or the like. The valve mechanisms 80 to 83 are operated by means of a camshaft 2|) driven from the" crankshaft 75, as described in connection with Fig. l. p h V V In Fig. 2 is shown a cross-sectional view of the compressor inlet valve shown in Fig.1 which also serves to show the construction and operation of theexh'aust valve of the air motor portion shown in. Fig. 1. In this construction the'fvalve mecha nism' is of the usual type employed in internal combustion engines in which an intake manifold passageway communicates with theinterior of the'cylinder 18 through a valve port 3| whichjs guarded by a port closing member 32. The port closing member comprises a valve head"33"which gagement with a disc or pin 38 mounted on the valve stem 34. The spring 31 thus tends to hold the valve head 33 in engagement with the seat of the valve port 3|. The rocker arm 36 is provided with a second" laterally extending projection 39 which is engaged by the valve operating rod I8 in such manner that the-cam 2I on the camshaft 20 raises the rod and thereby opens the valve twice during each revolution of the camshaft.

In Fig. 3 is illustrated a valve mechanism which may be employed either as the intake valve mechanism of an air motor or expander, or as the exhaust valve mechanism of a compressor. In Fig. 1, the exhaust valves 8| of the compressor may be identical to the exhaust valve structure shown in my Patent No. 2,011,780 of which thisis a division. In this figure I have illustrated the usual cylinder I9.provided with thecylinder headl2 in which is disposed a passageway 90 communicating with the cylinder 19 through a valve port III which is guarded by a valve head, 92, the latter being provided with an integral valve stem 93. The valve stem 93 moves within any suitable arrangement of valve guide 94. The upper end of the valve stem 93 is pro- .vided with a groove 95 in which is fitted a twopart locking collar 96 provided with a conical exterior surface and serves as a seat for a spring collar member 91. The valve stem is surrounded by two coiled'compression springs 98 and 99, which together serve to raise the valve head 92 from its seat when no pressure is exerted there- 'onby the rocker arm. j The valve stem 93 is provided at its top with a curved portion I which is engaged by a contactingmember IOI mounted upon an end portion of afocker arm I02. The rocker arm I02 is pivotally mounted upon a pin I03 mounted on the cylinder head I2. The rocker arm I02 is composed of a plurality'of leaf springs which serve to provide a resilient engagement between the rocker arm and the valve stem. The rocker arm I02 is provided'with an arm I05 on which is mounted an adjustable member I06 which in turn is engaged by the tappet rod I9 and with an oppositely disposed arm I04 which is engaged by a compression spring I Me which serves to raise the arm I02 when the member I9 is in its lowermost position.

In this particular construction there is normally a considerable, pressure in the chamber 90 which exerts a pressure on the upper side of the valve head 92 and serves to hold the valve closed. As the piston approaches the upper end of its stroke, there .being but comparatively little clearance between the cylinder head and the piston, the pressure createdthereby is suflicient, together with the aid of the springs 98 and 99, to raise the valve head 92 from its seat against the pressure in the chamber 90. When this occurs, the pressure is immediately equalized on both sides .of the valve head and the springs 98 and 99 open the valve wide instantly. The upwardly moving valve stem 93 engages the resilient arm I02 and is cushionedthereby, so as to prevent any sharp blows to any part of the valve mechanism, thus eliminating any slowness of movement resulting from the inertia of the valve head and valve stem. It will be apparent that by reason of the force of the springs 98 and 99 being additive to the pressure within the cylindenthe ,valve will start to open before the pressure in the cylinder equals that in the chamber 90. This small interval of time is suficient for overcoming the inertia of the valve closing member and its stem so that the valve actually opens at the time when the pressure in the cylinder is equal to that in the passageway 90. When the cam engages the tappet rod I9 it moves the rocker arm I02 downwardly, thus promptly and positively closing the valve through a resilient connection. The rocker arm may be raised immediately thereafter but the valve remains closed because of the pressure in the passageway 90 on the upper side of the valve head being greater than the pressure exerted thereon by the springs 98 and 99, and the valve will remain closed until the piston again reaches the upper portion of its stroke and pneumatically raises the valve, as previously described,

From this description it will be apparent that the air motor intake valve is positively mechanically closed at the desired predetermined point and is pneumatically opened during its normal operation' It will also be apparent that the come pressor exhaust mechanism is likewise mechanically positively closed and is pneumatically opened by the differential in pressure on the two sides thereof. In each instance the valve opens without any retardation caused by the inertia of the valve member and instantly opens widely. Also, in each instance, the valve closing member moving upwardly engages at the uppermost portion of its movement a resilient cushioning member which serves to eliminate shocks to the mechanism. I

Itshould also be understood that all the foregoing advantages of the air motor intake valve are obtained in the compressor operation by the correspondingly constructed exhaust valves thereof and' that the resulting perfection of timing of compressed fluid, discharge from the compressor and intake of. such 7 compressed'flu'id by the'air motor, results in an obtainment of efficiency which surpasses that of combined air motor and compressor units of conventional structure. vBy employing an improved valve mechanism of' this character and the precise parts of the motor and compressor specified, the system is conditioned, not onlyto make available the advantages ofthe'fluid compressor exhaust valve operationandthe advantages of the improved motor intake valve operation individually, but to so synchronize these related functions as to obtain an efiiciency. and accommodate speeds of operation far in excess. of what could be expected by the individual contributions of the ,im-. proved motor and compressor constructions, respectively. 7

Although I have illustrated but one specific form'of my invention, it will be apparentto those skilled in the art that my invention is not so limited but that various changes and modifications may be made therein Without departing from the spirit thereof or from the scope of the appended claimsw I What I-claimis: I

1. In an air motor having a cylinder provided with a movable piston; valvemechanism including an intake and an exhaust valve, each adapted to be pen d and o ed. said intake Valve being adapted to be opened by a combined mechanical and fluid pressure differential on opposite sides thereof and to be closed by positive mechanical means.

2. In an air motor having a cylinder provided with a movable piston; valve mechanism including an intake and an exhaust valve each adapted to be opened and closed, mechanical means adapted to close the inlet valve and to retain it in its closed position during a predetermined portion of the piston movement, said valve being adapted to be opened by a combined mechanical and fluid pressure differential on opposite sides thereof during other portions of the piston movement.

3. In an air motor having a cylinder provided with a movable piston; valve mechanism including an intake and an exhaust valve, said intake valve being of the poppet type, each of said valves being adapted to be opened and closed, mechanical means adapted to open and close the intake valve at predetermined points in the travel of the piston and to hold said intake valve closed during a predetermined portion of the piston travel, said intake valve being adapted to be opened by a combined mechanical and fluid pressure difierential on opposite sides thereof during other portions of the piston travel.

4. In an air motor having a cylinder and a movable piston, valve mechanism including an intake valve and an exhaust valve of the poppet type, each constructed to be opened and closed, said intake valve being constructed to be opened by a pressure differential on opposite sides thereof and to be closed by positive mechanical means.

ALLEN C. STALEY.

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