US59886A - William weight - Google Patents

Description

' @eine tstrs @anni @fitta IMPROVEMENT IN STEAM ENGINE GUT-OIT VALVE-GEAR.

WILLIAM WRIGHT', 0F NEW YORK,

Letters Patent No. 59,886, dated November 20, 1866.

Be it known that I, WILLIAM WRIGHT, of the city, county, and State of New York, have invented certain new and useful improvements in the Valves and Valve-Gear of Steam Engines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings forming part of this specification, in which` Figu're 1 is a horizontal section of the cylinder of a horizontal steam engine and of the induction valves and valve-gear.` l-

Figure 2 is a side view of the cylinder and valve-gear, valso exhibiting the governor in section.

Figure 3 isa longitudinal'vietv of the spindle and gearing by which the valve-operating cams or toes are adjusted by the governor or otherwise to make the induction valves operate as a variable cut-off.

Figure 4 is a transverse vertical section of the cylinder and valves in the planeindicated by the linea, rc, iig. I. l

Figure 5 is a horizontal section of one of the eduction-valve chests in the planeindicated by the line gy, in tig. l. i v

Similar letters of reference indicate corresponding parts in the several figures.

One feature of the invention consists in a novel valve-gear for operating the induction valves of a stean engine, whereby the said valves are made to produce a variablecut-off ivhich may be automatically adjustable `undcr the. control of a governor, or adjustable by other means.

In order that the above-mentioned valve-gear may operate with Ythe most perfect success orto the besI advantage, it is desirable that the valves should be, as nearly as practicabie, free from friction, or that the pressure of steam upon them in such direction as'would permit their free action-should be counterbalanccdf; ani although the application of the valve-gear is not limited to any particular kind of valve, the valves which I propose generally to use are of what may be termed the rolling-slide kind, having the longitudinal profiles of theil faces and'seats of the form of arcs of circles; and an important feature of my invention consists in certair devices in combination with such valves, whereby the -abovementicned desirable result is obtained.

To enable others skilled in the art to apply my invention to use, Iwill proceed to describe it with refercnev to the drawings.

A represents the cylinder of the engine, having separate ports, z', z", for vthe induction, and e, le', for th cduction of the'stcanr, thc induction portsf communicating with Vtwo separate steam chests, S S', onone side o the cylinder whichfare kept filled with steam frointhe boiler, when the engine is in operation, through a passage a, connecting them with one common steam pipe, and the eductien ports e'icommunicating with separate educ tion chests, C C', under the .cylinder connected with one common eduction pipe, D, (fig. 4.) I I' are theinduc tion`valv`es arranged one in each of the steam chests. These valves, in the example of my invention illustrata in the drawing-alare of the rolling-slide kind, having the longitudinal proles of their facesand seats of'th form of arcs of circles,` as shown in iig. l, and having an oscillating motion about the centres 5 b'. In orde that a proper amount of opening of the steam ports may be obtained with a small amount oi" motion of th valves, for the better operation of my variable'cut-off valve-gear, the valvesare made with ports, c c, vvhic communicate with two or more branches, o2 d, of the cylinder induction ports z'z', openinginto the valve seati The stems or Working rods, ff', of these valves are arranged parallel with the cylinder and pass through stufling boxes g, g, in both ends of their respective steam chests, S S', in order that they may bc relic-vcd o'fppressur of steam on their ends. The inner ends of the said stems are furnished with bevelled or rounded ends, h h', i order that they may be the better acted upon by the toes, j j', of the valve-operating cam, F. The valves I only effect the induction and cutting oli' of the steam, separate valves being used for eduction, as will be hereii after described.

The induction-valve-operating cam is carried by a hollow upright shaft, K, arranged in suitable fixed bea' ings in a position'between the Iheads of the valve-stems f f'. This carnhas a cylindrical body, and has in i4 exterior surface straight tangential grooves, of dovetail form in their' transverse section, for the reception of tl sliding-toes jj and j' j', which act upon the heads of the valve-stems to produce the opening movements of tl valves. The toes jj, for operating the valve I, arearranged above and at right angles to those, 7" j', for ope ating the valve I', and the heads, g g, of the valve-sten1s are arranged in a corresponding manner. The holle cam-shaft K is geared by an intermediate hollow horizontal shaft, L, and bevel-gearing, K' L' L M', with a horizontal shaft, M, which is driven by bevel-gearing from the crank-shaft of the'engine. As there are two toes for operating each valve, and each valve is required to be operated but once for each stroke of the piston of the, engine, the hollow cam-shaft is so geared as to make but one revolution for every two revolutions of the shaft M and crank-shaft. The toes jj and j' j' have on their straight yinner faces cogs which gear as shown in iig. 1, with long straight cogs, n n, or an upright spindle, N, which passes loosely through the hollow main spindle T, of a governor, P, (fig. 2,) which revolves freely, without any longitudinal movement, in a hollow fixed column, Q. The upper end of the said spindle N is so suspended fromthe governor at lc (fig. 2) that it will rise as the governor balls fly out from the centre, and descend as the governor balls approach the centre. The said spindle, which passes through the hollow cam-shaft K, has on its lower part a series of long spiral or worm cogs o1V threads, r r, which work like a screw, in a nut formed 'or fitted and firmly secured within the lower part of the hollow shaft K. The governor is driven by thel bevel gears m p g, (g. fromthehollow cam-shaft K, the gear m being fast on the cam-shaft, the gear p turning loosely on a fixed stud, 8, ,and the gear g being fast on the main spindle, T, of the governor. y i

It has been hereinbefore stated that the toes jj and j'j', of the cam F, produce the opening movement of the induction valves I I'. The return movement for cutting oli' the steam may be produced by weights or any other devices acting uponl the outer ends of the stems. The drawing (see igsfl and 2) represents spiral springs, t t, applied to the stems 'for this purpose. In the closing movement the valves may be stopped by fixed stops suitably arranged, but they are represented as being stopped by the inner ends of the stems coming into contact with the cylindrical portions of the cam F between the toes. The opening movement of the induction valves is greateror less, and the said valves are caused to remain open a longerf or shorter time, according to the degree of the protrusion of the toes, jj and j' jfbeyond the cylindrical portion of the cam K, The amount of this protrusion is regulated by the higher or lower position 'of the spindle N. The raisingvof this spindle causes it tov :urn on its axis within and independently of the hollow cam-shaft K, by the spiral cogs or threads, r r, working ln the nut in the lower part of the camshaft, and by this independent turning movement the straight cogs, nn, tre caused so to act upon the cogs of the toes and to draw the points of the latter inward; and the descent of ;he spindle is by' the same means caused to produce an opposite result. It will thus be understood, the governor,4 ts it begins to rise by any increase of speed, raises the spindle N, and so drawins the toes and reduces the length )f the opening movement of the valves and the time which they are all allowed to remain open; and as it falls, vith any diminution of speed depressies the said spindle and so produces an opposite result, thereby regulating he speed of the engine. To permit the'above action of the governor the connection ofthe spindle at k may be auch that the spindle N may be capable of turning independently of the governor. This must be the case vhether the governor rotates in the same direction with the cam-shaft K or" in the reverse direction, as-it does vith the system of gearing, m p g, hereinbefore described. The proper direction of the pitch of the spiral cogs n' threads, r r, will depend upon whether the governor rotates in the same directionI as, or the opposite direction zo, the cam-shaft K, owing to the spindle N rotating with the camshaft. By the use of two toes for operating iach valve, and thereby enabling the cam-shaft to be run at half the velocity of the crank-shaft of the engine, the engine may be run very fast and. yet the valve-operating cam may rotate slowly, and a very steep pitch of the ipiral cogs or threads is enabled to be used; although if the cam-shaft rotated at the same velocity as the crankhaft a single toe might be used with the same variable adjustment to operate both valves. This method of perating the valve to obtain a variable cut-ofi' is applicable to engines without a governor, the spindle N, in such zase, being adjustable lengthwise to produce the variable action of the cut-off, either by a screw, lever, or other :ont'rivance operated by hand. The mode of counterbalancing the pressure of steam on the induction valves I to obtain the proper freedom of operation, is illustrated in tgsi 1 and 4. The centres upon which the valves vscillate, consisting of pins b b', concentric with their faces and seats, are secured in or inserted through blocks if metal, R R', riveted or otherwise secured to bonnet-plates, U U', of steel or other metal thin enough to be uoderately flexible, applied to the backs of the steamchests S, S'. These plates have their inner faces exposed o the pressure of steam inthe chests and theirl outer faces exposed only to the pressure of the atmosphere. The said bonnet-plates are secured to, the valve-chests by means of rigid iiange-plates,- V V', and screw-bolts, in vhichI there are suitable openings, 7 7, fortheexposure of the said bonnet-plates to the atmosphere. The said onnet-plates being of suitable size, the pressure of the steam upon them so nearly balances 'the pressure on the racks of the valves as to allow their faces to be pressed only'just as close upon their seats as is necessary to ,eep them' tight. At the back of the valves there are applied set-screws, u, which screw vthrough fixed bridges, v, arranged across the opening, 7, outside of the {lange-plate V. vThese set-screws serve toprevehtlhe valves rom being pressed back too far from their seats by an excess of outward pressure' of the steam within the ylinder.' The connections of the valveswith the blocks R R', are iitted to slide-'between clie'eklpieces, 12 12, 1 the chests, which prevent any lateral motion, but permit the movement of the iexible plates and valves @ward and from the valve seats. The eduction valves E E', Vworking in the chests C C', below the cylinder, are onnected with and operated by separate cranks, Y Y', on the shaft M, which is parallel with the cylinder. The eats, W W', of these valves consist of plates which are fitted into grooves, ww', in the sides of the chests C C', s Ashown in iig. 2, and are faced and have the valves fitted .to them before being inserted into their places. This onstruetion of the valve seats aifords greater facility fo'r the accurate fitting of the valves than if they were )uned directly in the chests or on the cylinder.

What I claim as my invention, and desire to'secure by Letters Patent, is

1. `Thecogged sliding toe or toes and th spirally grooved or threaded longitudinally moving spindle N, in onibination with each .other vand with the cam F, and' valves, substantially as and for the purpose herein oecified.

2. The spirallycogged or threaded spindle N, so combined with the governor and the sliding toe or toes of the valve-operating cam as to have a longitudinal movement as the governor .rises and falls, and also to he capable of turning independently of the governor as the latter rises and fllig-substantially as and for the purpose herein speciiied. p

3. The combination of the rolling slide valves I I', with the flexible plates U U', substantially as herein described for the purpose herein set forth. i

4. The set-screwsfw u', in combination with the iexible plates U U', and valvesI I', substantially as and for the purpose herein speciied.

W. WRGHT.

Witnesses:

HENRY T. BRQWN, A. LE CLERC.

Images