US1219308A - Rotary valve. - Google Patents

Description

E. R. HOBBS.

ROTARY VALVE.

APPLICATION man 1uNE s. 1916.

Patented Mar. 13, 1917.

N rsmmx Mw @J SN Elbert R. Hobbs.

ELBEBT R. HGBBS, 03F SHL, IDAHO.

recrear vanvn.

Specification of Letters Iatent.

Patented Mar. 13, 1917.

Original application filed December 29, 1915, Serial No. 89,169. Divided and this application filed June 6,v

To @Z5 whom t may conce/m Be. it known that l, Ennnn'r R. Hoses, a citizen of the United IStates, residing at Buhl, in the county of Twin Falls and State of Idaho, have invented certain new and useful Improvements in Rotary Valves, of which the following is a specification, reference being had therein to the accompanying drawing. y

My invention relates to valve systems for fluid engines and more particularly to a system of control for rotary valves in reciproeating engines.

Asn object of my invention is to provide a system of rotary valve control whereby fluid may be let into each side of the engine cylinder at the same rate and in the same quantity.

Further objects of my invention are to provide various novel arrangements and combinations of parts whereby certain new and better results may be obtained in the art to which it pertains.

This application is a division of my prior application filed December 99, 1915, Serial No. 69,169, for rotary valve gear.

My invention is illustrated in the accompanying drawings in. which- Figure 1 is a plan view, partly in section, o f a fluid engine equipped with my invention.

Fig. 2 is a plan view of the valve seat.

Fig. 3 is a plan view of the intermediate valve member looking` from within the steam chest.

Fig. e is a plan view, partly in section, of the cap valve member, lookingfrom within the steam chest. y

Referring to the drawings in particular 4 is the enginecylinder, adjoining which is a cylindrical steam chest 5 whose interior is connected through short steam chiots 6 and 16 leading from opposite ends of the steam chest to the respective opposite ends of the cylinder.` The ducts 6 and 16 terminate in the steam chest in openings 7 and 17 in the valve seats 1 and 11 respectively. Intermediate valve members 2 and 19 engage the valve seats 1 and 11 and are in turn engaged by the cap members and 13, respectively. The cap members 3 and 13 are connected to each other by cylindrical telesconing extensions 9 and 19, held in fixed angular relation by means of pins 14 fixed in the extension 9 and engaging longitudi- Serial No. 101,961.

nal slots 15 in the extension 19. rlhese telescoping sections inclose an exhaust space 2() within the steam space 21 and are provided with an annular packing 22 interposed at the sliding joint in order to prevent the leakage of steam between the spaces 20 and 2l. The cap members 3 and 13 are rotated by means of the shaft 23 which passes through the member 13 and is fixed to the member 3.. This shaft carries a coiled compression springa 24 adapted to bear against 3 and 13 and hold them against the intemediate valve members 2 and 12. The intermediate member 12 is rotated by the hollow shaft Q5 to which it is fixed, and carries with it the other intermediate member 9 by means of the rigid arms 26 fixed to the member 12 and slidably engaging the member rlhis slidable engagement of the pairs of members 2-12 and 3-13 is provided in order to permit the members of each pair to move away from each other to taire up the wear. 1

The valve members 1-11, 2 12 and 3-13 cooperate in the sam-e manner as those described in the application previously referred to and differ only in form to adapt them to the arrangement here used. As the members 1, Q and 3 are substantially like the members 11, 19 13, respectively, a description of one set, 1, 2 and 3. will suffice. The engaging or bearing surfaces of the several valve members made conical in shape in order to keep them in alinement. A single radial opening 7 in the valve seat l connects with the steam duct 6 while a series of arc-shaped openings 10 near the center of the valve seat lead to an annular exhaust duct 8 connected with the atmosphere or a condenser through a suitable passage not shown. In the intermediate member 2 is a series o-f arc-shaped perforations 36 registering with the openings l0, and on opposite sides of the center are groups of radial perforations 27 and 28, an end perforation 29 and 30 in each group communieating with an arc-shaped recess 31 and 3Q, respectively, which recesses open only on the face engaging the valve seat 1 and are separated from each other at the ends a distance slightly greater than the width of the opening 7. Sockets 33 are formed in the member 2 near its periphery to engage the rigid arms 26, previously referred to, which sockets have their side walls parallel to the axial movement between the valve and theV arms while maintaining a constant angular relation. rIhe cap member 3 is formed with a recess 34 and a perforation 35 each adapted to communicate with one or more of the perforations in the groups 27 and 28 in the intermediate member, according to therelative angular position of the two members, the perforation 35 communicating at all times with the perforation 36. The spaces formed by the perfor-ations and recesses in the different members 1, 2 and 3 are so arranged and proportioned that when the members are superposed in the relative angular positions shown in Figs. 1, 2 and 3, the recess 34 and perforation 35 will be out of connection with the perforations 27 and 28, and the perfor- ations 27 and 28 and recesses 31 and 32 out of' connection with the opening 7. rThus, in this position, there is no passage of communication between the valve members excepting through the perforations 10, 36 Aand 35 which form the exhaust passage. However, if the cap member 3 is rotated in a clockwise direction, the recess 34 will be brought into communication with one or.` several of the kperforations of group 28, according to the amount of rotation, while the perforation 35 will be brought into communication with the same num-ber of perforations in the group 27 andv with the recess 31 via the perforation 29. It will be seen that by varying this adjustment, the amount of steam admitted to the cylinder through the opening 7 at each counterclockwise revolution of the members 2 and 3, as a whole, may be varied.

Relative rotation of the cap and intermediate member is effected by means of the concentric shafts 23 and 25 passing through and normally rotated as a whole with the cylindrical casing 37. The hollow shaft 25 is connected in fixed angular relation to the casing through axially movable clutch members, one member 38 fixed on the casing and the other 39 fixed on the hollow shaft by means of a collar and set screw or other suitable adjustable connection. The purpose of this clutch connection between the casing and shaft 25 is to allow the valve member .12 to move axially to compensate for wear and expansion. The solid shaft 23, which is lixed atone end to the cap member 3, is journaled at the other end in a journal bracket 40 carried by the casing 37 which journal connection is such as to allow slight axial movement of the shaft to compensate for wear ofthe cap member 3 and for expansion and contraction of the shaft or other parts. A bevel gear 41 xed to the shaft r23 meshes with a bevel gear 42 journaled in the bracket 43 carried by the easing Formed integral .with or otherwise fixed to the bevel gear 42 is a pinion 44 meshing wth the rack 45 slidably mounted on the casing 37. Thus axial movement of the rack 45 will be transformed into a relative rotary movement between the solid shaft 23 and the hollow shaft 25, while when the Era-ck is held against axial movement both shafts together with the casing 37 will remain in fixed relative angular relation.

rlhe casing bears at the end, opposite the steam chest, in a journal support 46 mounted in any suitable manner in fixed relation to the engine bed, not shown, and the casing is locked in the journal against axial movement by the' annular reduced portion indicated in dotted lines at 47, any expansion or contraction of the casing being compensated for by the clutch members 38, 39.

In order that the rack 45 may be reciprocated while the frame is rotating, it is carried by a rod 48 which connects with a sliding collar 49 j ournaled on the outside of the casing and adapted to be reciprocated along the casing by a slip ring 50. in arm 51 controls the movement of the slip ring and collar through a suitable transmission mechanism comprising the members 52, 53. and 54, the pivot 55 of the arm being fixed in relation to the engine bed, not shown. A suitable locking plate 56 is also provided for holding the arm 51 in any adjustment.

The engine shaft 57 is journaled in stationary bearings 58 and 59, and carries at one end a crank plate 60 connected with the piston 6l by the usual crank pin 62, link 63, wrist pin 64, and piston rod 65.

Motion is transmitted from the engine shaft 57 to the rotatable casing 37 through eccentric bevel gears 66 and 67 fixed respectively to the engine shaft and theA casing. rlhese bevel gears are fixed eccentrically and at an angle with their respective shafts, and in such relation to,v each votherthat they will always be in mesh while their intersecting radii will vary in inverse relation to each other. Thus. the frame 37 and with it the valve members 2v and 3 are given a variable speed in relation to the engine shaft the purpose of which i's to compensate for the variable speed of the piston and its utility wil-l appear Vfrom the-following, y

vAs the crank pin 62moves from the ex-Y treme right hand position 68, the link 63 connectingthe crank pin with the wrist pin 64, is caused to change its annular position so that the piston moves a distance equal to the crank radius plus the difference between the true length of the link and its'horizontal projection when the pin is in the position 69; and as the crank pin moves from 69 to 7 O, the piston is moved a distance equal to the crank radius minus the difference between the true length of the link and the said horizontal projection. 0n the other hand, in the back or return stroke, vthe crank pin moves from 70 to 69 in the first quarter turn, the piston will move the length of the crank radius minus the said difference, and then as the crank pin moves from G9 to (3S in the last back quarter turn the piston will move the length of the crank radius plus the said difference. Thus it will be seen that the piston moves faster during the first portion of its forward stroke than during the latter portion, while in the back stroke it moy es slower in the first portion than in the latter portion.

ln order` to allow the same amount of steam to enter both sides of the engine cylinder and at a rate proportionate to the speed of the piston, the valve must rotate with a greater speed during the latter part of the back stroke and first part of the forward stroke than during the latter part of the forward stroke and lirst part of the back stroke. Such a result is accomplished through the relative speed obtained between the engine shaft and the casing 37.

By the use of the novel arrangement of eccentric bevel gears herein previously described, l find that the variable relative motion between the piston and engine shaft can be elfectively compensated for while using a symmetrical two-way valve.

The operation of an engine making use of the type of valve shown herein is set out in detail in the application previously referred to, and it suffices here to describe a complete cycle of a charge of steam through one side of the engine cylinder, the cycle of the charge through the other side being identically the same.

Assuming that the intermediate valve member 2 is adjusted so that the inlet recess 34 is in communication with several of the perforations 28, and the exhaust perforation 35 in communication with the recess 3l via the perforation 29, and also that the space 31 in the steam chest is connected with a suitable source of steam supply not shown; the steam will first pass from the space 2l through recess 34, the irst one of the perforations 28, opening 7, steam duct 6, into the cylinder 4: back of the piston. As the piston moves forward, the steam continues to enter the cylinder over the path described through successive perforations 28, the valve starting fast and rotating at a retarding speed during the forward stroke. As the piston nears the end of the forward stroke, the flow of steam is cut off by the movement of the perforations 28 out of communication with the opening 7. At the beginning of the back stroke, the recess 31 is brought into communication with the opening 7 so that during the entire back stroke the exhaust steam will pass out to atmosphere or condenser via duct G, opening` 7, recess 31, perforation 29, exhaust chamber 20 and perforations 36 and 10. During the back stroke the valve first moves slow and rotates at an accelerated "speed during the remainder of the stroke, in order to supply steam to the other side of the cylinder at a rate proportionate to the backward movement of the piston.

in the driving mechanism of a valve gear it is important that lost motion be eliminated as nearly as possible, and to this end l have devised an effective means for taking up the lost motion in the gears, which means l have shown here in the form of a split gear G6. (See especially Figs. l, 5 and lThis consists in splitting or dividing the gear transversely and midway of its thickness and holding the two parts 66, 66h, together in such a manner that one may be slightly turned in relation to`the other and iXed in the adjusted position so as to take up any lost motion due to wear. ItV

will be seen that by such an adjustment the effective width of the teeth is increased, the lower portion 661 of the teeth taking the wear when turning in one direction and the upper portion 66 taking the wear in the opposite direction.

Having thus described my invention what l claim and desire to secure by Letters latent is:

l. In combination, a reciprocating engine having a cylinder and reciprocating piston therefor connected through a pitman and crank to a shaft for rotating the same at a substantially constant rate of rotation, a rotary valve for controlling the admission of fluid to the cylinder at each side of the piston, and motion translating means connected between said valve and said shaft for rotating said valve in substantially constant relation to the rate of rectilinear movement of the piston.

2. In combination, a reciprocating engine, a rotary valve therefor, and a variable motion transmission mechanism between a moving part of the engine and said valve for rotating said valve at a decreasing speed during the forward stroke of the engine and at an increasing speed during the back stroke.

3. En combination, a reciprocating engine and shaft therefor rotated at a substantially constant speed, a rotary valve for controlling the admission of iiuid to the cylinder of the engine, and an operating shaft therefor, and a pair of intermeshing eccentric bevel gears each connected to one of said shafts and so proportioned as to cause said valve shaft to rotate in substantially constant relation to the rectilinear movement of the piston of the engine.

1l. In combination, a reciprocating engine having pitman and crank connection between the piston and the engine shaft, a

rotary valve for controlling the admission of fluid to the engine cylinder on both sides of the piston with driving means therefor',

and motion transforming means between said v engine shaft and the valve driving means adapted to compensate for the variable speed ratio between the piston and engine shaft' due to the said pitman connection.

5. 1n a Huid engine, a reciprocating driving part and a rotating driven part with a variable speed driving connection between them, a rotary valve controlling the supply of fluid to said reciprocating-part, and variable speed gear connections between said rotating part and said rotary valve so arranged as to transmit motion from said rotating part to said rotary valve constantly during the operation of the reciprocating part, in a speed ratio inversely proportionai to the speed ratio between the reciprocating driving part and the rotating driven part of the engine.

In testimony whereof I aiHX my signature.

ELBERT R. HOBBS.

copiesA of this patent may be obtained for ve eentsA each, by addressing the Commissioner of Patents. Washington, D. C.

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