US1213274A - Valve-gear for piston-engines. - Google Patents

Description

E. SCHMID.

VALVE GEAR FOR PISTON ENGINES.

APPLICATION FILED MAY 22. I9I4. 1,213,274. Patented Jan.23,1917.

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mmm/WIM @IMM E. SCHMID. VALVE GEAR FOR PISTON ENGINES.

APPLICATION FILED MAY 22. I9I4. 1,213,274. Patented Jan.23,1917.

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ERNST SCHMID, 0F OERLIKON, SWITZERLAND.

VALVE-GEAR FOR PISTON-ENGINES.

Specification of Letters Patent.

Patented Jan. 23, 1917.

Application led May 22, 1914. Serial No. 840,221.

T 0 all whom it may concern Be it known that I, ERNST SoHMiD, a citizen of the Republic of Switzerland, residing at Oerlikon, Switzerland, have invented new and useful Improvements in Valve- Gears for Piston-Engines; and I do hereby declarethe vfollowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to let-ters or figures of reference marked thereon, which forni al part of this specification.

The object of the present invention is to provide an eilicient packing for valve rods and more especially valve rods of an explosion motor or air compressor and all cases where a valverod is to be packed with respect to a cylinder head; and the invention consists in providing one or more chambers in which the gas escaping from the cylinder during compression expands and is exhausted from said chambers during the suction period by periodically connecting the chambers with the space in thecylinder for the charge of gas.

One form of carrying the invention into effect is shown by way of example in the accompanying drawings in which:

Figure l shows a longitudinal section of an explosion motor, the working piston and the valve gears being illustrated in the position which they take-up at the beginning of the explosion period. The parts not necessary for the understanding of the invention are omitted. Figs. 2-6 show the same longitudinal section, the different parts being illustrated in other working positions. Fig. 2 shows the parts in the position which they take up at the beginning of the exhaust period, Fig. 3 shows the parts in the position, which they take up atthe beginning of the admission period, Fig. 4 shows said parts in the position, which they take up when the admission opening is half opened and Fig. 5 shows them in the position, which they take up when the admission opening is completely opened, Fig. shows the parts in Jthe position, which they take up at the beginning of the compression period.

1 denotes the working cylinder surrounded by a cooling jacket 2.

3 denotes the working piston, 1 the piston rod, 5 the crank and 6 the crank shaft.

7 denotes a water cooled cylinder cover 11 by means of its edges.

lprojecting into said chamber.

sion is provided all around with channels around the whole cylinder, so that very large admission and outlet openings may be provided. Between the cover 7va'nd'the working pistonfS there is' arrangedv an annular slide valve 12. The outerl diameter of this valve 12 is in the present instance equal to the inner diameter of the` cylinder 1. No outlet-passages are provided in this valve 12 and the latter controls the channels 10 Vand Two piston rings 13 and 14 surrounding the valve prevent a leakage of gases during the explosion and compression periods. The-lower piston ring 13 is moved at times into the position, which had been previously taken up by the upper piston ring 14: of the working piston 3 so that it is not necessary to provide a special lubrication for the annular slide valve 12, the required lubrication being effected by the working piston 3. Inside the slide 12 there is provided a cross-piece 16 to which the stem 17 of said slide 12 is fixed. The stem 17 passes through the sleeve 8 and the nut 9 and it is guided in a socket 18 disposed above the cover 7. The stem 17 has a longitudinal bore 19 extending over a part of its length. Two upper ports 2O and two lower ports 21 extend from said bore to the outer surface of the stein. rlhe latter has moreover an annular recess 22. The sleeve 8 confines a space 23 forming an expansion chamber and it has a tubular extension 24 This exten- 25, which are in communication with the cylinder 1. The nut 9 and the cover of the sleeve 8 confine a space 26, which acts also as an expansion chamber.l To the stem 17 of the annular slide valve there is operatively connected a double armed lever 28 pivotally arranged above the cover 7 inside the casing 27. The two ends of saidlever are pivotally connected by means of rods 29, 30 to the cranks 31, 32, which receive their drive from the shafts 38, 34. The shaft 311 receives its drive from the crank shaft 6, there being provided for this purpose either chain wheels 35, 36 and a chain 37 or toothed wheels, the ratio of transmission being 1 :1.

@n the other hand the motion of the crank shaft G is also transmitted by means of the sprocket wheels 3S, 39 and the chain 40 to the shaft 83, the ratio oi.I transmission being 1:2. n

s The manner of operation of the slide valve 12 irill be evident from the drawings. The large size of the admission and outlet openings prevents a backing up of the gases during the exhaust period and the formation oi" a vacuum during the suction period, notwithstanding the fact that the number of revolutions is very high. The compression and explosion pressures are transmitted to the lower part or the stem 1T of the slide valve 12 and the channels 10 and l1 are arranged one near another, so that the slide valve 12 may be made short and very light.

The tightening of the stem 17 is accomplished in the following manner: The Working fluid, for instance gas, which during the explosion period (Fig. 1) leaks through the clearance existing between the outer surface of the stem 17 and the inner surface of' the tubular projection 241 passes into the chamber 23, Where it will immediately eX- pand. 1t is clear, that these gases can only pass into the chamber 23 during the com pression, explosion and exhaust periods.-

During the suction period the chamber 23 Will be connected by means oit the channels 25, the ports 21, the bore 19 and the ports 20 to the space for the charge or the cyl' inder (Fig. 1), so that the gas which may have leaked into this chamber 23 Will be sucked out when new gases are sucked in the cylinder. For the purpose of facilitating the flowing back ot these gases thel connection between the chamber 23 and the Working cylinder 1 is made during the suction period. As shown in Fig. 5, the second expansion chamber 26 will only be opened after the expansion chamber 23 is already in communication with the space for the charge, said chamber 26 acting only as a safety chamber. The gases, Which may have leaked into the chamber 26, are then sucked through the annular recess 22 into the chamber 23 and from the latter into the cylinder 1. Experience has shovvn, that even in cases, Where the stem 17 ot the slide valve 12 has a considerable play in the tubular projection 2e and in the Whole nut 9, no gas Will escape into the atmosphere. This proves that the time interval between the end of a suction period and the beginning of the next suction period is too short to permit the explosion pressure to be transmitted through the chamber 28 to the atmosphere and it proves further, that the channels for the flowing back oi the gases are suliiciently large to convey the gas, Which may eventually have leaked into the chamber 23, back into the space for the charge during the suction period. This arrangement permits a good tightening o the stem 17. This could not be effected if piston rings were used, as the diameter of these rings would be so small that they would be practically of no value. Also the packings used in stuiling boxes would not permit satisfactory results. The hereinbefore described tightening may also be used at the place, where the gasolcne is directly injected into the cylinder. 1n this case the injection is also eii'ected through the ports 20, the bore 19. the ports 21 and the channels 25. As the back-pressure acting upon the stem 1T is very small, the socket 18 may be made very light. The annular slide valve 12 may -also be provided with ports for the gas and it could also be acted upon by only one connecting rod. The stem oit' said valve could also be arranged at an angle to the axis oi" the cylinder. This annular slide valve may further be provided in connection with every kind of valve gears and the shafts 3S and 84 may also be arranged in the head of the cylinder. rllhe content of the chamber 26 could also be sucked out during theV outlet period. Instead oi providing in connection with the nut 9 a single chamber 26 there could also be provided several such chambers arranged one behind another, which would then be successively emptied into the Working cylinder 1. There Ina-y also be provided only one expansion chamber.

W'hat I claim is:

1. In a packing for valve rods of combus tion engines, the combination with a valve rod projecting through the iva-ll of the eny gine cylinder, of a chamber surrounding the valve rod and adapted to receive and permit an expansion of gas escaping from the engine cylinder around the valve rod, said rod having means :tor connecting periodically the chamber and cylinder, to permit the gas in the chamber to be sucked through the valve rod from said chamber into the cylinder.

2. In a packing for valve rods of combustion engines, the combination with a valve rod projecting through the Wall of the engine cylinder, of a chamber surrounding the valve rod and adapted to receive and permit an expansion of O'as escaping from the engine cylinder around the valve rod, said valve rod having means for connecting periodically the chamber with the charge space of the cylinder to permit the gas in the chamber to be sucked through the valve rod from the chamber into the cylinder.

3. 1n a packing for valve rods of combustion engines, the combination with a valve rod projecting through the Wall of the engine cylinder, of a plurality of annular eX- pansion chambers surrounding theV valve rod and adapted to receive and permit an expansion of gas escaping from the engine cylin der between the valve rod and the inner walls of the cylinder, said rod having means for connecting the chamber with the charge space of the cylinder during the suction period to permit the gas in the chamber to be sucked through the valve rod from the chamber into the cylinder.

4. In a packing for valve rods of a conibustion engine, the combination with a valve rod projecting through the wall of the engine cylinder, of a plurality of annular expansion chambers arranged in tandem and surrounding the valve rod and adapted to receive and permit an expansion of gas escaping from the engine cylinder between the valve rod and the inner wall of the cylinder, said rod having means for connecting the chambers with the charge space of the cylinder during the suction period to permit the gas in the chamber to be sucked through the valve rod from the chamber into the cylinder. v

5. In a packing for valve rods of a combustion engine, the combination with the engine cylinder, of a cylinder cover, a hollow sleeve arranged centrally in said cover, a tubular extension in said sleeve projecting into the hollow space of the latter, a nut screwed in the cover, an annular chamber provided between the sleeve and the nut, a valve rod passing through said tubular eX- tension and nut and having a longitudinal hollow portion, ports leading from said hollow portion to the surface of the rod, channels in said tubular extension connecting the space for the charge of the engine cylinder with the hollow portion oi' the rod, and an annular recess in the valve rod for connecting the hollow sleeve space to the chamber provided between the sleeve and the nut. In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

ERNST SCHMID. lVitnesses CARLY GUBLER, ARNOLD LEHUER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents. Washington, D. G.

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