US1738435A - Cam-operated balanced valve gear for steam locomotives and like engines - Google Patents

Description

Dec. 3, 1929.

q. KUPKA 11338435 GAM OPERATED BALANCED VALVE GEAR FOR STEAM LOCOMO'IIVES AND LIKE ENGINES Filed June 28., 1926 2 Sheets--bhee'lzV l v,A s 1@ y A@ 39 Q 45@ Q mi? m 5 4 MWVEW'W J. Mmmm l,738435 OPERATED BALANCED VALVE GEAR FOR STEAM LOCOMOTIIVES AND LIKE ENGINES Filed Jun@ 28, 1926 2 Sheets-Sham; 2

Patented Dec. 3, 1929 UNITED STATES JOHANN KUPKA, F LONDON, ENGLAND CAM-OPERATED BALANCED 'VALVE GEAR FOR STEAM LOCOMOTIVES AND LIKE 'ENGIN ES Application filed June 28, 1926, Serial No. 119,177, and in Great Britain July 24, 1925.

This invention relates to improvements in the distribution valves of steam engines of the balanced poppet or mushroom type in which the valves are operated by cams or 6 tappets. In valve mechanism of this kind. the thrust of the cam or tappet is transmitted vdirectly to the valve stem, or indirectly theresteam to the engine of which the valves form.,

a part. By thus keeping the valve stem or roller thereon in contact with the part by which it is moved, closure of the balanced mushroom or poppet valve at the required time is ensured without the use of any spring or like metal part. For this purpose a part of the valve stem is arranged to serve in effect as a piston, or a piston is provided to act on the valve stem, in order to move the valve to its closed position.

In the accompanying drawings, which show how the said invention can be conveniently and advantageously carried into practice,l

Figure 1 is a sectional view through partof a steam chest showing a steam engine valve i,

arranged in accordance with the invention.

Figures 2,3, 4 and 5 are similar sectional views respectively illustrating modifications of the arrangement shown in Figure 1.

As shown in Figure 1, 1 is a part of a valve chest with steam passages 2, 3 and a cam chamber 4c formed therein. Communication between these passages is controlled by a valve 5 mounted on a valve stem 6 on which the valve proper is held by nuts 7 allowingv the position of the valve to be adjusted on the stem to vary the effective length of the stem, for example, by inserting washers between y the hub of the valve anda shoulder 8 formed on the valve stem against which the valve hub can rest. At the opposite end of the Valve stem to that on which the valve 5 is mounted, a roller 9 is rotatably mounted upon the end of the valve stem extending into the cam chamber 4 so as to lie in the path of a cam 10 carried on a cam shaft 11 within the cam chamber. The valve stem\is slidably mounted in a sleeve 12 secured in the valve chest and serving also as a guide for the webs 13 of the valve, the sleeve being slotted to provide prongs 14 between which'the valve webs 13 can slide, whereby rotation of the valve and its stem is prevented so that the roller 9 isikept in proper position to .be acted upon by the cam. The valve stem 6 is made hollow and at an intermediate part of its length apertures 15 are formed to provide free communication between the hollow interior of the valve stem and an annular pocket 16 provided in the said sleeve; Steam is admitted to this pocket through a pipe 15aL from a suitable source so as to maintain a suliicient pressure within the hollow valve stem.

At the end of the'valve stem opposite to that acted upon by the cam or tappet, a Isliding plunger 17 is provided, forced outwardly7 from the valve stem by the pressure existing therein, into contact with an abutment 18 on a removable cover plate 19 closing an aperture in the valve chest 1 through which access can be had to the valve. The pressure existing within the hollow valve stem keeps the plunger 17 and the roller 9 at all times in contact with the abutment 18 and the cam 10, respectively, whilst the cam operates through the roller to open the valve, which is returned to its closed position when the cam allows the appropriate movement of the valve stem, the length of which is suitably adjusted with this intention.

In the modified construction illustrated in Fig. 2, the end of the valve stem acted upon by the cam or tappet 10 is arranged as a piston 20 to slide in a sleeve 21 secured in the valve chest l and this piston carries a rod 22 guided in a liner 23j, The hub 24 of the valve is slidably mounted on the rod 22 and is held thereon in the required position of adjustment between the packing 10o pieces or washers 25 and nut 26. A guide sleeve 27 mounted in a cover plate 28 is provided to prevent rotation of the valve and valvevstem. The .liner 23 is provided With a lcollar 29 held between one end of the sleeve 21 and the guide sleeve 27. The valve is closed by the pressure of steam admitted through a port 30 to act upon the effective area of the piston 20, whilst opening of the valve is effected by the cam 10 acting on the roller 9 and thereby moving the rod 22 as required.

In some cases, instead of admitting steam to a space between the valve stem and the sleeve by which it is guided, one end of the valve stem 31, Figure 3, is carried into a liner 32 removably held in a cover plate 33 by a bush 34. Steam is admitted into the liner by a steam pipe 35 and acts upon the valve stein so as to tend to close the valve and keep the valve stem in contact with a lever 36 interposed between a plug 37 at one end of the valve stem and a rotary calm 38, acting through the said lever to effect the opening of the valve. The lever 36 is pivotally supported at 39 and carries a roller 40 to receive the thrust of the cam. As shown in Figure 3, the valve 5 is screwed on the valve stem 31 on which a collar 41 is provided to determine the position of the valve. When the cam is arranged to act on the valve stem through a plug and an interposed lever-as shown, a guide to prevent rotation of the valve, such as the prongs 14 in Figure 1, canbe dispensed with.

In order to obviate any difiiculty which may arise in the use of the arrangement illustrated in Figure 3 owing to want of alignment between the valve stem and the removable cover plate, a separate piston 42, as in Figure 4, can be mounted in the chamber 43 in a removable cover plate 44, to which steam is admitted through a steam pipe 45, this piston abutting against one end of the valve Stem 46 which may be formed by a nut 47 holding the valve 5` on the valve stem. The sleeve 12 in which the stem 46 is guided is held in position by a screwed plate'48 and l is furnished with valve guides 14.

A similar arrangement to that shown in Figure 4 is illustrated in Figure 5 in which the cam` 9 actsion the valve stem 46 through an interposed lever 36.

The cams or tappets for operating the valves can be enclosed in a chamber 4 to which steam can be admitted through an inlet 49, and itis lthen possible, by suitably controlling they supply of steam to the chamber aio . maintaining within the valve stein sleeve, or within the removable cover plate, and the supply of' steam to the cam chamber, to provide for the valve in theopen position with the va ve stem out of the range of the crm or tap et,.or the interposed lever, for example, w en the engine is vrunning free as in the case of a `locomotive travelling on a down grade.

It is to be noted that this improved arrangementof valve gear is applicable to stationary and marine engines as well as to locomotive engines.

I claim:

1. Valve actuating mechanism for steam engines, comprising a hollow valve stem having its interior isolated from the valve chest, a piston slidably mounted at one end of said valve stem, a cover plate with which the piston is in contact, a valve associated with said stem, a cam for actuating said valve stem to move the valve into its open position, and means for supplying fluid under pressure into the interior of the valve stein to maintain the end of said valve stem in contact with said cam.

2. Valve actuating mechanism for steam engines, comprising a hollow valve stem having its interior isolated from the valve chest.

.a piston slidably mounted at one end of said chamber for actuating said valve stem to .move the valve into the open position, means for supplying fluid under pressure into the interior of the valve stem to move said v alve stem and close the valve, and means for supplying fluid under pressure to said cam chamber for holding the valve open independently of the cam.

3. Valve mechanism for steam engines, comprising a valve, a hollow stem associated with said valve and having its interior isolated from the valve chest, a piston slidable at one end of said valve stem, a cover plate with which the piston is in contact, means for adjusting the position of the valve iclatively to the stem, means for supplying fluid under pressure to the interior of the valve stem to move said stem and close the valve, and a cam for opening the valve against the action ofthe fluid under pressure.

4. Valve mechanism for steam engines, comprising a valve, a hollow valve stem associated with said valve, a cam for opening the valve, a piston slidably mounted at the end of said valve stem remote from the cam, a cover plate with which the piston is in contact, and means for supplying fluid under pressure to the interior of the valve stein to move said stem and close the valve.

5. Valve mechanism for steam engines, comprising a valve, a hollow stem associated with said valve and having its interior isolated from tlie valve chest, a guide for the valve preventing rotation of the valve about the longitudinal axisy of the stem, a piston slidably mounted at the end of said valve stem remote from the cam, a cover plate with which the piston is in contact, means for adjusting the position of the valve relatively to the length ot the stem, means for supplying fluid under pressure to the interior of the valve stem to rnove said stem and close the valve, and a cam for opening the valve against the action or the duid under pressure in said valve stem.

6. Valve mechanism tor steam engines, comprising a valve, a hollovv valve stein associated with said valve, a piston slidaloly mounted at the end of said valve stem remote from the cam, a cover plate with which the piston is in Contact, means for varying the e'ect'ive length of said stem, means for supplying Huid under pressure to the interlor or' the valve stem to close the valve,

and a cam for opening the valve against the fluid under pressure in said valve stem.

7. Valve mechanism for steam engines, comprising a valve, a valve stem associated with' said valve, a stationary chamber in aXial alignment with said valve stem, a piston moving in said chamber and having its head projecting therefrom into contact With the end of the valve stem, means for supplying fluid under pressure to said chamber to move said piston and close the valve, and a cam in Contact with the end of the valve stem remote from said piston for opening the valve against the action of the Huid under pressure.

8. Valve mechanism lor steam engines, comprising a valve, a valve stem associated with said valve, a cover. plate, a chamber in said cover plate in axial alignment with said valve stem, a piston moving in said chamber and having its head projecting therefrom intol Contact with the end of the valve stem, means for supplying fluid under pressure to said chamber to move said piston and close the valve, a cam chamber, a camin s aid cam chamber-for opening the valve against the action of the fluid under pressure, and means for supplying Huid'pressure tosaid cam chamber for holding the valve open independently or the cam.

JUHALNN KUPILM.

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