US2011123A - Means for stopping internalcombustion engines - Google Patents

Description

Aug. 13,1935. 5. w. SHILSON El AL MEANS FOR STOPPING INTERNAL COMBUSTION ENGINES 2 Sheds-Sheet 1 Filed Dec. 3. 1931 [271 522 [0219 ier/7422i )fiW/am 5/5/60 Aug. 13, 1935. B. w. SHILSON ET AL 2,011,123

MEANS FOR STOPPING INTERNAL COMBUSTION ENGINES Filed Dec. 5, 1931 2 Sheets-Sheet 2 1 571/62; fans;

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.45 switches, while Patented Aug. 13, 1935 PATENT OFFICE MEANS FOR STOPPING INTERNAL- OOMBUSTION ENGINES William Shilson and Harry Cantrlll, Coventry, England, assignors to Armstrong Siddeley Motors Limited, Coventry, England Application December 3, 1931, Serial No. 578,760

In Great Britain December 24, 1930 SCIaims. (01. 123-91) This invention relates to internal-combustion engines, particularly air-cooled aircraft engines, and it has for its chief object to provide simple and effective means whereby the engine may be i stopped quickly and with certainty when a control is actuated.

This is very important on seaplanes of the tractor type, where one of the occupants has to go forward into the neighbourhood of the propeller to effect mooring to a mooring buoy. It is also extremely important on aircraft which land on aircraft-carriers or ship decks.

The invention also prevents any possibility of the engine firing after it is switched ofl, even if there would normally be a tendency towards selfignition, which may occur with. either watercooled or air-cooled engines.

According to this invention, each cylinder is provided with a valve which is normally shut but which can be opened to the atmosphere throughout the whole cycle to arrest the engine, all these valves being actuated by a single control device.

According to a further feature of the invention, the engine ignition switch is connected with the control device aforesaid so that, when the latter is moved to open thevalves, the ignition of the engine is cut oif. Preferably the connection is such that, even if the control device is returned to its normal or running position, the ignition remains oil and must be separately returned to the running or "on position when the engine is subsequently to be used.

In the accompany drawings,

Figure l is a fragmentary side elevation of a star type aircraft engine embodying this invention,

FigureZisanenlargedviewofpartoftheengine cylinder of Figure 1, the cylinder and its air valve being shown in axial section,

Figure 3 is a transverse section, to a larger scale, through the control mechanism, taken on thelineIIIIlIofFigurel,

Figure 4 is a side view of the operators control lever, and shows ditically a method of interconnecting the lever with dual ignition Figure 5 is a'planview of the arrangement shown in Figure 4, but with the switches in the 50%; Like numerals cylinder head 4 an aperture 5, and fitted into this aperture there is a body 8 having a seat I with which co-operates a mushroom valve member I. The space 9 behind the head of this valve communicates directly, with the outer air by passages ill, it, so that, when the valve is unseated, air' can pass through it in either direction. A spring [I normally holds the valve member seated and various devices may be provided for unseacing the said valve member.

In the particular arrangement shown, the valve body 6 is externally screw-threaded at l2 and receives a bracket it, which is locked in the de-.

. sired angular position thereon by means of a nut II. This bracket carries a small bell-crank lever It, the short arm of which engages the stem of the valve member 8 while the long arm thereof is connected to a cable It passing through a lug l'l on the bracket. This lug'also forms an abutment for a Bowden wire casing I. which surrounds the cable and a spring I! around the exposed part of the cable assists to return the bell crank lever I! to normal position as the valve closes.

In an engine of the type illustrated, all the cables are conveniently connected to a common actuating member 25, such as is shown in Figures 1 and 3. For instance, the cable from each of the small air valves to the common control mechanismmay be secured by clips 20, 20 to the intake manifold 2|, as shown in Figure 1. In this case, the various Bowden wire casings II, It are secured to abutments 22, 22 on a bracket 23 secured to the rear part of the engine and having bearings 2|, 24 in which there is mounted a vertical shaft 25. On this shaft there are secured one or more radiallyextending members 26, 2 through which the ends or the cables pass and to which they are adjustably secured, as at 21. The radial membars 26, 26 are associated with arcuate guides 28,

28 secured to the shaft 25 insuch a manner as to give a straight line pull'onthe cables where they pass through the abutments 22, 22. The shaft 25 has secured thereto a crank arm 20 which is connected, as by a Bowden cable ll, or other connection, to a control lldisposed conveniently to the hand of the pilot or operator.- Thus, by moving this control all the Bowden cables l6, l6 are actuated and all the small air valve members 8, 8 are opened or allowed to close simultaneously.-

Preferably the ends of the Bowden wire casings l8, l8 engage compression springs 32, 22 arranged in the abutments 22,22, these springs acting to equalize the pulls on the various cables when the control arm isiactuated,'so that all the valves I will be opened to the same extent irrespective of whether some of the cables have become more stretched than others.

When the operator wishes to stop the engine quickly, it is therefore merely necessary for him to close the engine throttle valve, switch 013? the ignition, and move the control arm 3! in the requisite direction to open the air valves against the action of the springs l l, is, holding them open until the air-friction which opposes the pumping of air into 'and out of the cylinders through. the small valve passages it, ill plus the friction of the moving engine parts, has been sumcient to bring the engine to a standstill. It will be clear that, as pure air is admitted directly into the cylinders, there is no possibility of this air picking up any mixture in the'fuel intake system and so causing an explosive mixture. Furthermore, should any mixture find its way into the cylinders during the suction strokes after the engine throttle valve has been closed, the reduced compression prevents any possibility of this mixture being fired by self-ignition.

With such an arrangement there is, of course, a risk of the operator forgetting to switch off the ignition when moving the control arm to stop the engine, in which case the engine might conm'ience to fire again should he happen to release the control arm before it has actually stopped.

To avoid this, in the arrangement shown in Figures 4 and 5, the control arm 3! (which may be mounted at the side of the cockpit or cabin of the aircraft), is connected withthe ignition switch in such a manner that the ignitionis automatically cut ofi when the control arm is moved to open the valves and is not switched on again when the arm is subsequently released.

For example, the arm 3!, when-moved to open the valves, is arranged to engage the tumblers 33, 33 of a pair of switches 3d, 3d controlling a dual ignition system (Figure 4) and move them into the oil position. These switches are so mounted as to have their tumblers inclined to the plane of motion of the arm and thus the tumblers, when in the off position (Figure 5), cannot again be engaged by the said arm, but must be separately returned to the o position when it is desired to re-start the engine. Obviously the same arrangement can be used with a single ignition switch or with a master switch controlling a dualignition system, while the switching-off oi the ignition may obviously, if desired, be efiected by some part of the mechanism connecting the control arm to the air valves, instead of by the arm itself.

Obviously, mechanical means other than those described, may be provided for operating the valves.

What we claim as our invention and desire to secure by Letters Patent of the United States is:-

1. The combination with an internal-combustion engine having electrical ignition means and a manual control therefor, of a valve adapted for venting the engine cylinder, means for operating said valve when desired, and means mounting said operating means for contact with said manual control to cut oil the ignition when the valve is operated for venting the cylinder, said manual control being movable independently oi said operating means upon closing of the valve,

2. The combination with a multi-cylinder engine having electrical ignition means and a controlling switch thereof, of a valve for venting each cylinder, control me io'r operating said valves having an opening therein, valve fittings in the cylinder openings having passages placing the internal spaces of the cylinders in communication with the outside atmosphere, said fittings also having valve seats, inwardly opening mushroom valves cooperating with said seats, light spring means for urging said mushroom valves against the seats assisted by internal pressure within the cylinders, a device at each valve for opening the same against the light spring pressure, a unified central control means, and flexible control cables connected between the several devices and the unified control means.

4. The combination with an internal combustion engine having electrical ignition means and a manual control therefor, of braking means for effecting quick stopping of the engine, and an operative connection-between said manual control and said braking means for operating the manual control to switch off the ignition means when the braking means is moved to braking position. said manual control being independent of said braking means on movement of said' braking means to released position.

5. In combination, an internal combustion engine having an ignition means, a manual control therefor, and a plurality of cylinders each of which is provided with an opening placing the internal spaces of the cylinders in direct communication with the outside atmosphere, said openings being relatively small with respect to the cylinder capacity, valves for controlling said openings, operating means for controlling the opening and closing of said valves, and means mounting said operating means for engagement with said manual control to cut ofi the ignition on opening of the valves, said manual control being independent of said operating means when said valves are closed.

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