US1450112A - Reciprocating-piston engine - Google Patents

Description

Mar. 27, 1923.

H. FILLING RECIPROCATING PISTON ENGINE Filed June 10 1922 w n h Fatented Mar. 27, 1923.

PA TENT @FWE.

HENRY FILLING, OF CHORLTON-C'UM-HABDY, ENGLAND.

RECIPBOCATING-IPISTON ENGINE.

Application filed June 10, 1922. Serial No. 567,395.

To all whom it may concern.

Be it known that I, HENRYPILLING, a subject of the King of Great Britain, residing in Chorlton-cuIn-Hardy, England,

have invented certain new and useful Improvements in Reciprocating-Piston Engines, of which the following is a specification.

In United States Patent No. 1,153,133 ar- 1 rangements are described in order to prevent the pressure of the steam in a cylinder of a reciprocating piston engine from attaining an undesirably high value during the return stroke after the main exhaust ports have been closed. The arrangements comprised auxiliary exhaust valves, communicating with the cylinders at or near the inlet ends, which were automatically opened during the return stroke of the engine if the no steam pressure in the exhaust passage of the engine exceeded a predetermined value. Means were provided by which the period during which the valves were kept open depended on the exhaust pressure of the en- 326 gine, v

The present invention consists in an improved device for operating the auxiliary exhaust valves. The device is more especiall applicable to uniflow steam engines but it is not restricted to use with this type of engine. a

, According to the invention, in order to regulate the opening of each auxiliary exhaust valve, a cam is provided on a'shaft gages with a roller or the like suitably connected to the valve spindle- The profile of the cam is adaptedto impart travel to the spindle and, consequently, a duration of opening of the valve which varies from nil to a maximum value.

The cam is mounted on a sleeve adapted to slide on the shaft and its longitudinal position is determined at any time in dependence on a piston sliding in a cylinder, one end'of the cylinder being connected with the exhaust passage and the other end with the atmosphere. If the cylinder pressure increases, the piston is moved in the cylinder .in a direction which causes the cam to slide on the shaft and operate the valve.

A cam is provided for the auxiliary exhaust device in the cylinder'head. I

The cam shaft is, preferably, hollow and rotating at the speed of the engine and en-- the interior of the shaft and is connected by cotters or other means to the two cam sleeves disposed respectively opposite the cylinder covers.

When the engine is working, ifthe pressure in the exhaust passage is suficie ntly low, the position of the piston and consequently of thecam sleeves is such that the section of the cams opposite the rollers connected to the valve spindles imparts no travel to the spindle and the auxiliary exhaust valves remain closed. Should the ex haust pressure rise above a predetermined value which may be any 'pressuredetermined upon and for which the machine is constructed the cams will be moved along the cam shaft into positions in which the cams lift the valves once in every revolution of the engine.

As the exhaust pressure increases the cams will cause the-auxiliary exhaust valves to reinain open for a longer period and the final closing of all steam exits from the cylinder is delayed and the pressure to which the steam is compressed by the main piston of the engine .on its return stroke cannot exceed a safe value.

The accompanying drawing shows in sectional plan an example of a construction according to the invention as applied to a uniflow steam engine.

Fig. 1 shows in a single view the entire construction of ap'plicants device.

Fig. 2 is a detail view showing the construction of the cam and the slidable relation of the cam to the shaft.

Fig. 3 is a section on the line 3-3, Fig. 2, showing the connection of the cam to the reciprocating rod.

1 is the cylinder, 2 the piston, ,3 the exhaust belt or passage communicating with the interior of the cylinder through passages 3", 4 the cover of the inlet end of the cylinder and 4 is the inlet valve. The hollow cam shaft 5 has two cam sleeves 6 (one only of which is shown) secured to the rod 8 by the cotters 7 workingin slots 5 in the shaft 5- adapted to slide longitudinally within the shaft 5 and to carry with it the cam sleeves 6' and cams 9 secured to the sleeves.

The cam shaft 5 is'SupPOIted in. -bearings 10 and 11 located in arms 10" and 11' respectively depending from the engine body and is driven at the Speed of the and 13.

The rod 8 is connected by a collared joint 14 to a control piston 15 adapted to slide steam tight in a control cylinder 16, the inner end of which is open to the atmos phere and the outer end 17 of which is connected by a pipe. 3 to the exhaust passage 3. If the exhaust pressure increases beyond. a predetermined amount, the piston 15,-aided by the tension of a spring 18, is drawn towards the left and returns to its normal position under the atmospheric pressure when the exhaust pressure decreases. It will be understood that there may be a disclosure of other suitable meansof any usual type connected with the exhaust belt 3, this disclosure being no part of the invention and is therefore not illustrated.

As the cam 9 slides to the left it engages with aroller 19 carried by a crosshead-20 connected to the spindle 21 of a valve 22 inserted in the cylinder cover 4 and communicating when open with the interior of the cylinder 1 by means of a port 23. The

valve is normally kept closed by a spring 24, but when opened by the cam 9 there is a passage from the cylinder through the port 23, to a pipe 23 leading from the valve chamber to the exhaust belt.

The cam 9 is so formed that the period durin which the valve is open increases as it 1s moved to theleft by the increasing pressure of the exhaust acting on the auxiliary exhaust piston 15.

When the en ine is first started the cam is in such a position that the valve 22 opens at each compression stroke of the engine and as the vacuum is improved the piston is moved against the resistance of the spring 18towards the right and draws the cam 9 clear of the roller 19 and puts the auxiliary exhaust valve 22 out of action.

' The cross section of the cam 9 is so formed that the valve is not opened until after the main exhaust ports of the engine have been uncovered by the engine piston and there is, consequently, no interference withthe expansion of the steam during the outgoing movement of the piston. The specific construction of the cam as shown constitutes no part of the invention.

Having thus described the nature of the said invention and the best means I know of carrying the same into practical effect, I claim 2-- 1. In combination with the piston cylinder of an engine having intake and exhaust passages, a valve for relieving pressure in the cyllnder, means for automatically operating said valve comprising, a rotatable cam-shaft, a cam slidable on said shaft and adapted to open and close the valve, means to prevent rotation-ofthe cam relative to the cam-shaft, and means under influence of the pressure in the exhaust passage and of a spring cooperating with said pressure for sliding said cam to operative position.

2. In combination wth the piston cylinderof an engine having intake and exhaust. pas sages, a valve for relieving pressure" in the cylinder, means for automatically opening said valve under the influence of pressure in the exhaust passage when said pressure ex-' ceeds a predetermined amount comprising a cam-shaft,- a cam longitudinally slidable on the shaft, means for preventing rotation of the cam relative to the shaft, a control cylinder in communication at one end with the exhaust passage and open at its opposite end to the atmosphere, a piston in the cylinder connected with said cam, a spring in the control cylinder adapted to assist the exhaust pressure and means on the valve by which the valve is operated through the movement of the cam.

3. In combination with the piston cylinder of an engine having intake and exhaust passages, a control valve for relieving pressure in the cylinder, means for automatically opening said valve when the pressure in the exhaust passage exceeds a predetermined amount comprising, a cam-shaft, a cam longitudinally slidable on the shaft, means for preventing rotation of the cam relative to the cam shaft, a control cylinder in communication at one end with the exhaust passage and open at its opposite end to the atmosphere, a piston in the control cylinder connected with said cam, means on the valve by which the valve is operated through the movement of the cam, a spring in the control cylinder for assisting the exhaust pressure, the cam being so constructed that the period during which the valve is held open varies with the pressure in the exhaust passage.

4. In combination with the piston cylinder of an engine having intake and exhaust passages, a control valve for relieving pressure in the cylinder, a stem on said valve, a roller on said stem and means for maintaining the valve normally closed, a tubular cam-shaft, means for rotating said shaft in accordance with the speed ofthe. engine, a rod movable longitudinally in the bore of said shaft, a cam slidably mounted on the shaft and connected with said rod, an auxiliary cylinder in communication at one end with the exhaust passage and open to the atmosphere at the opposite end, a piston in said cylinder secured to the rod, and means under the influence of the pressure in the exhaust passage and of a spring cooperating with said pressure for sliding said cam to operative position.

5. In'a reciprocating piston engine, having. a cylinder with intake ,and exhaust passages, a tubular shaft, means for rotating the shaft at the speed of the engine, a cam slidably mounted on said shaft. a rod secured to said cam movable longitudinally in the bore of the shaft and having a piston at 5 one end, an auxiliary. cylinder in which said piston is adapted to reciprocate, said auxiliary cylinder being open at one end to the atmosphere and in communication at its opposite end with the exhaust passage, the first named cylinder having a port at its intake end, a control valve for said port, and means rigidly secured to said valve adapted to be operated on by said cam.

In testimony whereof I have signed my name to this specification.

HENRY FILLING.

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