US1294121A

US1294121A - Hydraulic transmission.

Info

Publication number: US1294121A
Application number: US5910115A
Authority: US
Inventors: Willard E Lape
Original assignee: WILLIAM J LEWIS
Current assignee: WILLIAM J LEWIS
Priority date: 1915-11-01
Filing date: 1915-11-01
Publication date: 1919-02-11
Anticipated expiration: 1936-02-11

Description

w. E. LAPE.

HYDRAULICA TRANSMISSION. APPLlcATloN men Nov.1. |915.

1,294,121. i Pated Feb.11,1919i 4 SHEETS-SHEET l.

7- o may.

W. E. LAPE.

HYDRAULIC TRANSMISSION. APPLICATION FILED Nov. l, |915.

me l

Umm,

" Patented Feb. 11, 1919.

W. E. LAPE.

HYDRAULIC TRANSMISSION.

APPLICATION FILED NOVI I', I9I5.

1,294, l 21., y Patented Feb. 11, 1919.

4 SHEETS-SHEET 3.

.W. E. LAPE. HYDRAULIC TRANSMISSION. APPLICATION FILED 111011.19151A 1,294,121., y Patented 1811111919.

4 SHEETS-SHEET 4.

somewhat similar WILLARD E. LAPE, or sYnAGUs-E, NEW Yo RK, ASSIGNOR OF ONE-HALF T0 WILLIAM J.

LEWIS, OF SYRACUSE, NEW YORK.

HYDRAULIC TRANsMissIoN.

Specification of Letters Patent.

Application filed November 1, 1915. Serial No. 59,101.

To all fuhom it may concern: l

Be it known that I, VILLARD E. LAYE, a Citizen of the United States of America` and resident of Syracuse1 in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Hydraulic Transmission, of which the following, taken in connection with the accompanying drawings, is a full, clear, vand exact description.

This invention relates to certain improvements in hydraulic power transmission as applied more particularly to engine-driven road vehicles to take the place of the usual variable speed gear transmission and gear differential mechanisms, the variable speed ldevice being Somewhat Similar to that set forth in in v Patent No.- 1,168,216, issued January 11. 1916,- while the combined vari-A able speed mechanism and differential is to that set forth in in v Patent No. 1.235.817, issued August 7 1917.

The main object is to establish a direct h vdraulic drive between the 'engine shaft and rear Yaxle sections in such manner as to automaticallyY produce a differential speed movementof the axle sections and traction wheelsl to compensate for the differential travel of the wheels in turning corners.

Another object is to provide simple means whereby the traction wheels may be caused to travel forwardly1 or 'rearwardly under `variable speeds for propelling the vehicle l in either direction under corresponding speeds.

A further object is to provide simple means controlled by the operator for c ausing both rear axle sections to be positively driven in the same direction and at the same speed when desired` as for example when one of the traction wheels tends to slip, whilel the other has a. rm grip upon the road-bed,

thereby assuring a more positive drive of the 1' I u machine under allA conditions within the range of power of the engine.

A still further object is to provide means' for relieving the fluid conduits from excess ressure as for exam le in sudden startinf' or stopping, of the machine when the controlling valve is quickli-Y opened or closed.

Other objects and uses relating to specific parts of the apparatus will be broughtout in the Yfollowing description, A

In the drawings-- Figure 1 is a top plan of a portion of an engine-driven road vehicle showing inv improved means of transmitting motion from the engine shaft to the rear axle sections.

Figs. 2. 3. and l are a longitudinal vertical sectional view and transverse vertical sectional views taken, respectively, on lines 2*-2, 3 3, and 1 -4, Fig. 1.

Y Fig. 5 is an enlarged lengthwise vertical sectional viewtaken on line 5-5, Fig.y 1.

Fig'. G is an enlarged transverse sectional view taken on line G-G, Fig'. l.

Fig. 7 is a horizontal sectional view taken approximately. in the plane of line 7-'7. Fifi. 2.

Figs. 8, 9 and 10 are detail sectional views of thevalve case and valve showing the valve in different positions.

'rammen rei). ii, raie. y

Fig. 11 is an enlarged transverse vertical sectional view taken on line 11-11. Fig'. 1.

Fig. 12 is a perspective view of tae detached hollow partition shown in section in Figs. 3' and 5 for separating the adjacentends of the rotors on the rear axle sections and for receiving the clutch for locking the axle sections to each other.

Fig.' 13 is a perspective view of one of the clutch sections shown in section in Figs. V2 and 5, and a top plan in Fig. 7. Practically the entire mechanism forming the subject-matter of my invention is inclosed within a suitable housing, preferablyv of cast met-al, and composed of separable see tions -1- and '-Qfhaving substantiallyT fiat Vfaces or ends secured together by clamping bolts -3- so as to forma substantially unitary. structure when assembled. the ser tion 1 constituting what may7 be termed the'. rotor case for receiving a. pair of similar pistons or rotors -'lwhich in turn are secured to separate co-axial axle sections -5- rarrving; the traction wheels, not shown.

while the other section 2 constitutes what.

may be termed the impeller-and-valve case -6 and valve. are chambers one. about substandriven by' a shaft -8- of a suitable engine, not shown, while the valve -7- is provided with a stem -9- extending through the end wall of the valve case for connection with any suitable operating means under the control of the driver.

The rotor case -1- is provided with re- -movable end heads 10- normally closing the outer ends of the chambers in which the rotors -4-' are adapted to revolve, and tightly held in place by clamping bolts l1- to form an air and liquid tight joint Aand constituting a practically unitary p-art of the rotor 'case when in operative position, each head being provided with an outwardly extending bearing -.l2- in which the adjacent portions of the axle sections 5 are journaled.

rllhe inner ends of the rotors -4- are 1 short distance beyond the corresponding faces of the rotors, but a. sufficient distance to the rear ofthe adJacent end of the valve and impeller case to allow free flow of thel iinpelling fluid from the valve chamber to both of the rotors.

The main `purpose of this partition is to divide the inflowing fluid from the valve chamber and -to direct-the separate currents against their respective rotors and tokeep such currents separated while traveling around.l t'he rotors to the outlet gfor impart-A mg rotary motion thereto with approximately equal force when both wheels vare traveling at the same'speed under approxivmately the same traction resistance.

It is evident, however, that if `the wheels are travellng at different speeds, as for example 1n turning corners, the resistance of the rotor correspondingI to the slower movrotorcorresponding to the faster .moving` wheel, thereby automatically establishing a ratio of velocities of the fluid acting u-poning wheel would cause the fluid to be diverted with', greater velocity against the other both rotors corresponding to the ratio of speeds of the wheelscorresponding to said rotors and producingin effect a hydraulic differential which willperform its function with the same or greater degree of eiiciency than the usual gear differential. j

' Another functionv of the partition -13- is to provide a convenient means for receiving the clutch by kwhich'the two rotors .and their axles may be locked to each other in a manner presently described for positively driving both traction Wheels 'when desired, as for example in case one traction wheel should tend to slip upon an icy, wet or soft bed, while 'the traction of the other wheel is more secure, under which conditions without the locking device the entire power would vbe diverted to the slipping wheel without propelling theA- machine, whereas by bringing the. locking device into action the entire hydraulic power would act upon both rotors with the same degree of force and would in most cases assure the propulsion of the machine. l

This locking device, as shown more clearly in Figs. 3, 5, 7 and 13, comprises a clutch section or collar -15- splined for sliding act-ion co-axially upon the inner end of one of the rotors -Jlwithin the hollow partition 13- and provided with recesses -16- for interlocking engagement with suitable clutch members -17- on the adjacent inner face of the other rotary section -ll-f.

The means for operating the clutch collar 15e comp-rises, in this instance, a rock ing yoke -18- engaging in an annular groove in the periphery of t'he collar and secured to a rock` shaft-19Mv which is journaled in the partition -13- and extends upwardly above the top of the case where it is provided with an operating member #-20- for connection with any suitable actuating means Within convenient reaching distance of and operated byhthe driver, said clutch being'normally held in its inoperative position by a retracting spring -21-, Fig. 5. Y

The hollow partition 1S- is preferablyV left open at the top and bottom to permlt the clutch collar -15 with the yoke -18- and lower section of the`rock shaft ,19-- to be properly installed therein before the partition `is inserted in thecase section -1-, said rock shaft being composed of lower and upper telescoping sections splined one upon the other so that the'upper section may be connected to the lower section through the tube of the case after the clutch and lower section have been installed in the partition, as shown more clearly in Fig. 5.

Whenl this partition is secured in place, it

becomes for all practical purposes a'unitary part of the case sections -1- and divides the interior thereof into separate chambers L22- for the rotors 4.-. w

These chambers 22.- are provided with separate ports -23- and *24:- leading, respectively, from thelower and upper -sides of the rotors through the front ofthe case section -1- and communicating with the .adjacent end of a valve chamber -25- atcorresponding sides of the valve -7- which -is movable in said valve chamber so thatv when the valve is adjusted to the position shown in Fig. l0 to allow the circulating fluid to pass from the-lower side of the the center of the chamber Q5- through the port -23-, the rotors will be driven in one direction for propelling the machine forwardly, while on the other hand it' the valve is adjusted to either of the positions shown in Figs. 8 and S), the circulating fluid will pass from the upper side of the. valvel through the corresponding port t'or driving the rotors in a reverse direction, thereby driving the machine backward.

The rotors--consist of similar circular drums secured co-axial to their respective axle sections and each provided with a pair of diametrically disposed plates -26- slidabley endwi'se in diametric slots or ways -27- in their corresponding drums and having their outer ends contacting with the Wall of thecorresponding chamber so as to form a iiuid tight rnnniiig joint therewith, said plates constituting wings or abutinents against which the impelliiig fluid impinges for driving the axle sections and traction wheels connected thereto.

The Vchambers -22- arc of greater cross sectional area than the corresponding area of their drums vand are eccentrically disposed thereto in such manner that all diameters thereof extending through the axis of the rotors are equal to the length ot the blades, the inner walls, as -28- of the chambers between the ports 23 and 9A- being concentric with the axis of the rotors for contact with the peripheries thereof, thereby producing an automatic cut-off between said ports at the inlet and outlet sides of said chambers, and at the same time affording a` passage -29- connecting the port' w23- with the lower portion of the valve chamber -25-.

Direct communication between the passage -29- and port -2-'lis cut otf by a partition -30-.- extending forwardly from the upper portion of the Wall -28- and preferably forming a portion of the case section -1- and also a bearing for the inner end of the valve -7-'`,` as shown more clearly in Fig. 2.

The ends of the rotors abut against. the adjacent faces of the end heads 10- and partition W13- to form fluid tight ruiming joints therewith.

The impeller -Gf and chamber in which it is movable are similar, but somewhat smaller than the rotors -4- and their chambers` in that tliey'consist. of a circular drum 231- and diametrically extending blades B2- movable in corresponding guides -33- and having their outer ends contacting with the "Walls of a chamber -,34 which is o'f greater cross sectional areafthan the corresponding area of the drum and eccent-rically disposed thereto so that all diameters' thereof passing through drum will be substantially equal to the length of the'blades,

more shoulders 22;

thereby ot the blades to forni fluid tight ruiming walls of the chamber.

The inner face ot' the upper wall, .as -%5-, ot the chamber 34 is concentric with the axis of the drum El and is located between opposite passages #3G- which connect the corresponding sides of. the chamber with suitable ports SlT- in diainctrically opposite sides of the valve chamber --25-, as shown more clearl)v iii Fig. 4, the latter being separated from the impeller chamber by the wall or partition 35 The inner end ot' the Vinipeller chamber is closed by plate -35- held in place by thc adjacent end ot the iinpeller and one or 230'- cxtcnd'ing forwardly from the inner wall 2S-1 of the case section --1,-, as shown more clearlyv in Fig. 7.

The opposite ends oi the iinpeller tiabut, respectively, against the inner tace ot the plate 35'- and outer wall of the impeller chamber to torni fluid tight ruiming joints therewith.

The valve 7 consists ot' a hollow plate disposed diainetricalljv within the chamber -25 and extending troni end to end thereof, said plate being provided with one or more transverse passages --38-n therethrough from side to side for connecting the ports -37- and allowing the iinpelling iuid to circulate therethrough when the valve is in its neutral position` as shown in Fig. 4. the opposite edges otl the, valve plate being concentric with its axis ot niovenient to torni tluid tight turning joints with the. valve case.

The thickness ot the valve' plate is considerably less than the dianicter of t'he valve chamber in which it is movable so asto leave considerable space at opposite side thercot' for communication with the vports and -Q4-.

The inner end of the valve abuts against the adjacent face of the partition #304- cooperating thercwith to forni a thiid tight turning joint. and at the lsaine time to cut off'communication between the. portions of the valve chainber at opposite sides of the valve plate abutting against the outer end head of the valve chamber, as shownin Fig. 2, for the same purpose.

`The stem --of the valve constitutes an operating means therefor "and may be coniiected to any other actuating meansv within convenient reaching distance of and actuated by the driver when seated in the vehicle.

iIlie ease section #-2- is providedwith an auxiliary chamber -25-^ formlng an extensionof the valve chamber -25- and is also provided with a transverse partition -3 9 being provided at opposite sides of the axis of the valve with separate ports 40- which i are normally closed by reversely arranged valves 41 through the. medium of comparatively stiff coil springs 42- so that if the pressure of the circulating iuid at either side of the valve 7 should exceed that at the other side of the valve, it would open the 'correspondingrelief valve 41 and thereby equalize t-he pressure, the purpose of the valves 41 being to prevent excessive pressure at either` side of the valve 7 thereby balancing said valve so that it may be operated freely at all times, and at the same time maintaining a uniform pressure of the iuid throughout the circulating system.

This excess pressure would be produce/d if the valve 7 lwere suddenly closed to its neutral position while the machine is in motion, particularly at high speed, during which the revolving traction wheels would' become the driving means for the rotors l1- which would tend to ram the Huid into the valve chamberat one side of the valve 7 thereby causing a -sudden stoppageof the rotors and consequent skidding of the traction wheels until such pressure was partially relieved by the automatic opening of one of the valves 41- againstJ the action of its retracting spring 42 Under these conditions, the machine will be brought to a sudden stop which, of course,

would be detrimental to the machine and could only be prevented by the gradual clos-- ing of the valve 7 i In order to overcome this objection and to allow the trac-tion wheels and rotors to revolve freely with thepower shut off, as in coasting, I have provided an auxiliary valve 7( located in the partition 30 and havlng a diametric opening therethrough movable into and out of registration with:

ports 71- in opposite sides of the chamber in which the valve 70 is mounted, the valve opening and ports 71 being common to both of the rotors 4.-, and when the valve is open constitute a passage throu h which the fluidmay be freely circulated y the rotors when thevalve 7 is closed or in its neutral position.

It is desirable that the operation of the valves 7 and 70 should be approximately simultaneous so that when the valve 7 is moved to its neutral position to cut off communication between the impeller Chamber and rotor chambers, the valve will be opened and vice, versa, and for this purpose the -stem of the valve 7 0 is provided with agear or toothed segment 72 meshing with a toothed rack 7 3 on one end of ran operating bar 74 arm 81 on the stem 9 of the valve.

-The first-named arm of the bell crank lever 79 is connected by a link 82 to an operating lever 83- loca'ted within easy reaching distance of and adapted to be operated by the driver of a vehicle. making anlopening through the valve 70 it may be completely opened or closed by a quarter turn movement in either direction,

and in order that this movement in eitherv direction may be limited so as to assure the positive closing, the teeth ofthe pinion 72 are formed in approximately onehalf of its periphery so that the opposite ends of the remaining uncut portion will form limiting stops coperating with the rack 7 3 which will also limit the movement of the rackin either direction, said rack being held in mesh with the pinion by a bearing 74.

The springs 77 l are of sufficient, tension to transmit Imotion from the bell crank 79- to the rack bar 7LL for opening Aand closing the valve 70 but are free to yield when the rack and pinion are brought to the limit `of their movements 1n either direction for closing said valve, thus permitting a continued movement l of the bell crank lever for additionally opening the main valve 7- to its full open position, it being understood that `when the valve 7-- is in its neutral position, the valve 7 0 is full open and that thel operating mechanism 'is adjusted so as toclose the valve 70 immediately upon the'beginning of the opening of the main valve 7 In operation the entire circulating system is filled with a non-freezing liquid, as oil,

which also constitutes a lubricant for the moving parts. 'The engine is thenstarted in the usual manner, thereby' drivlng the impeller 6 through the medium of the engine shaft 8 and if the valve 7 is adjusted to the position shown in Figs. 2 and "1', it will cut o1 communicationbetween theiinpeller chamber and rotor chambersaand establish communication between the opposite sides of the impeller chainber through the

passage

36, 38, and 36, thus vallowing the fluid to be,` circulated t in the direction indicated by the arrows propelling the machine 'in eitherwithout direction. A

If it is desired to propel themachine foriso" Wardly, the valve will be adjusted to or toward the position shown in Fig. 10 to open communication between the port -37-, at the left-hand of Fig. 4, and the portion of the valve chamber -25- below the valve -7-, and to also open communication between the opposite port f-37-and the portion of the valve chamber above the valve, thereby causing the circulating fluid to tlow from the lower portion of the valve chamber through the passage -29- and port -23- to engage the rotor blades 2(3* and drive the rotors -land their corresponding axle sections and traction wheels in the direction indicated by arrow -X-, Fig. 2, the circulating Huid being returned over the top of the rotors through the ports Q4- to the upper side of the valve chamber and thence back through the ports -87 and passage -36-- at the righthand of Fig. 4 and to the corresponding side of the impeller, thus completing the circuit which is repeated by the continued operation of the impeller in the same direction.`

On the other hand, if it is desired to propel the machine backwardly, the valve -7- will be adjusted in the reverse direction, as shown in Figs. 8 and 9, so as to open communication between the port -36, at the left-hand of Fig. 4, and the upper vside of the impeller chamber above the valve 7, and to also open communication between the passage -36- at the right-hand of Fig. 4-

and lower portion of the valve chamber b e low the valve, whereupon the impelling tluld will be forced from the upper portlon of the valve chamber through the port 24- and against the blades at the upper sides of the rotors, thence around the rear sides lof said rotors and back through the ports -Qf and passages -29- into the ,valve chamber at the lower side of the valve, whence `it re4 turns through the port -37- and passage;l 36 at the right-hand of Fig. 4 to the corresponding side of the impeller -6-, the:

' completing the circuit for reverse drive and permitting a continuation of the flow of the fluid in the same direction as long as the valve remains in the positions shown in Figs. 8 and 9, or in an'y other intermediate posi*- tion, it being understood that the speed ol': movement of the machine will dependupon the degree of opening of the valve 7-.

It -is-now evident that if the traction resistance on both Wheels is approximately the same as in ordinarydriving, the hydraulic power applied to both rotors will be approximately equal and that when the machine is turning a corner with the result that the outer-wheel will travel faster than the inner wheel, the differential speeds will cause the rotor corresponding to the traction wheel 'moving' at the highest speed to be driven with a corresponding velocity, while that corresponding to the slowerl moving inner wheel will be driven with a slower motion corresponding to such reduced velocity, owing to the fact that the resistance to rotation of the slower moving wheel will be greater than that of the faster moving wheel, and that the ilu-id will follow the course of least resistance.

lt is also evident that in endeavoring to drive the machine straight ahead or reverse if one of the traction wheels should slip and the other wheel maintain a firm traction grip upon the pavement, the resistance offered by the rotory corresponding to the gripping wheel would cause practically the full power of the circulating fluid to act upon the rotor corresponding to the slipping wheel, thereby driving the latter vat a high rate of speed, while the gripping wheel would remain stationary, which, of course, would preventV driving of the machine v-in either direction, and in order toobtain the deslred traction necessary to propel the machine under these conditions, the clutch -15 may be oper-A ated to lock both rotors and their axle sections together, thereby preventing the rotaull power of the circulating fluid to both rotors fory rotating the gripping wheel, which, in most cases,l will extricate the machine from the diiiiculty of propulsion, and as soon as both wheels are on solidground or operating with the same degree of traction, the machine will move along in the usual manner.

It, for any reason, the pressure of the fluid at one side of the valve should become eX- cessive, as for example by reversing the valve while the machine is in motion, this excess p ressure would be exerted upon the corresponding valve -41- to open the same against the action of its retracting spring 42%. thereby relieving the strain upon the valve and other parts of the-mechanism.

. `What I claim is: v-

l. ln hydraulic power transmission, the combination of a fluid-driving element, coaxial luid-driven elements` separate chambers for said elements, a valve chamber connected byv certain. passages tothe chamber of the fluid-driving element and by other passages to the chamber ofthe fluid-driven element. and a valve controlling said passages. so that in one position theiluidwill be caused to travel through the secondnamed passages in `one direction, and in tion of the slipping wheel and applying the another position the fluid will be 'caused to travel through the same second-namedpassages 1n an opposite direction, said valve having means for connecting the first-named said valve and the Huid-driven element to allow the latter to rotate freely when the valve is closed.

2. In hydraulic power transmission, the combination of a Huid-driving element, independently revoluble fluid-driven elements, separate chambers for said elements, a valve chamber connected by separate ports to the j chamber of the fluid-driving element, a valve divlding said yvalve chamber 'into separate compartments communicatingthrough sepa-- rate ports with the chambers for the driven elements, said valve being adjustable to connect either compartment with either of the first-named ports, and the other compartment with the otherfirst-named port.

3. In hydraulic power transmission, the combination of a fluid-driving element,rin dependently revoluble fluid-driven elements, separate chambers for said elements` a valve chamber connected by separate ports to the chamber of the fluid-driving element, a valve dividing said valve chamber intoseparatc compartments communicating through separate ports with the chambers for the driven elements, said valve being adjustable to conlneet either compartment with either of the first-named ports, and the other compartment with the other first-named port, and provided with a passage for connecting the first-named ports when adjusted to a certain position for cutting off communication between the first-named chambers.-

' one compartment should exceed that in the other compartment.

5. In hydraulic power transmission, separately rotatable co-axial pistons, and chambers therefor, in combination with enginedriven means for circulating a fluid through lsaidchambers circumferentially around the pistons for driving the same, and means operable at will for locking the pistons to each other to prevent the rotation of one independently of the other.

6. In lhydraulic power transmissionfor road vehicles, the combination with" separately. rotatable c-axial axle sections and separate pistons secured thereto, of aV hous-l ing for said vpistons'having separate ports leading from one side of and circumferentially around the same', engine-driven means for circulating a yliquid through said ports and laround the pistons for rotating both pistons and their axle sections in the same direction, and means operable at will for locking the axle sections to each other to cause them to rotate at the same speed.

7. In a motor-driven vehicle, the combination with an engine-driven shaft and separate co-axial axle sections jat right angles to said shaft, of hydraulic means for transmitting rotary motion from the shaft to the axle sections .comprising a housing inclosing the adjacent ends of the axle sections and shaft, and containing an impelling uid, an impellerin said housingsecured to the shaft for circulating said fluid, separate co-` axial rotors on the axle sections also within the housing and driven by said circulating Huid, clutch sections on the adjacent ends of the axle sections, and means for engaging and disengaging one clutch section with the other.

8. In a motor-driven vehicle, the combination with an engine-driven shaft and j separate co-axial axle sections at right angles 'to said shaft, of hydraulic means for transmitting rotary 'motion from the shaft -to the axle sections comprising a fhousing inclosing the adjacent ends of the axle sections and shaft, and containing an impelling fluid, an impeller in said housing secured to the shaft for circulating said fluid, separate rotors on the yaxle sections also within theY housing and driven by said circulating fluid, and means for locking the rotors to rotate in unison.

9. The combination with an engine-driven shaft and separate co-axial axle sections of a motor-driven velhicle, ya housing inclosing the adjacent ends of the axle sections and engine shaftl and provided with separate rotor chambers', a valve chamber and an 1mpeller chamber, separate co-ax1al rotors secured to the axle sections and movable ini' their respective chambers, a. rotary valve movable in the valve chamber, a rotary 1m-.

peller secured to the engine shaft within the impeller chamberhports leading` from the rotor chambers to the valve chamber at opposite sides of the valve,` additional ports lea-ding from opposite sides of the impeller to dia-metrically opposite sides of the valve chamber, said valve being provided Wirth a transverse passage therethrough for con-` necting the last-named ports when the valve-' gt is in its neutral position, and means for adjusting said valve in either direction from its neutral position to connect either Aport with either side of the valve chamber.

10. In hydraulic power transmission for road vehicles, a pair of independently revoluble coaxial rotors, a housing thereforl ments, and adjustable to connect either compartment with either passage and the other compartment with the other passage, and engine-driven means for circulating a motive fluid through said compartments and passages when the valve is so adjusted.V

l1. In hydraulic power transmission for road vehicles, the combination With a pair of independently revoluble 'coaxial pistons, and a housing therefor provided with Separate inlet and exit passages extending through one sidearound the opposite side of -the pistons, of an impeller. chamber and a ing with one of said passages.

` l2. In a device of the character described, a housing having a rotor chamber',` an impeller chamber and a valve chamber containing, respectively, a pair of independently revoluble coaxial rotors, an impeller and a valve, the VValve chamber having opposite ports communicating with the impeller chamber at opposite sides of the impeller,

said valvc dividing its chamber into two compartments communicating through sepa- `rate passages with the rotor chamber, the

valve vhaving a passage therethrough normally connecting said portsand adjustable to cut off communication between its passage and port-s and to simultaneously connect one compartment with one of the passages and the other compartment with the other passage. 3

In Witness whereof I have hereunto set my hand this 14th day of October, 1915.

WILLARD E. LAPE.

Witnesses:

H. E. CHASE, ALICE M. CANNON.