US1713992A - Brake mechanism for automotive vehicles - Google Patents

Description

M y 1929-, c. s. BRAGG'ET AL. I 1,713,992-

BRAKE MECHANISM FOR AUTOMOTIVE VEHICLES Filed Sent. 8, 1927 Patented May 21, 1 929.

PATENT OFFICE.

CALEB s. ammo, or PALM BEACH. FLORIDA, AND VICTOR w. KLIESRATH, or roar WASHINGTON, NEW YORK, ASSIGNQRS TO BRAGG-KLIESRATI-I CORPORATION, ,OIIE LONG ISLAND CITY, NEW YORK, A CORPORATIC "F NEW YORK.

BRAKE MECHANISM FOR AUTOMOTIVE VEHICLES.

Application flled September a, 1927, Serial No. 218,119, and in Canada August a, 1928.

Our invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate one embodiment of the same, se-

lected by us for purposes of illustration, and

the said invention is fully disclosed inthe following description and claims.

In the operation of vacuum brakes for automotive vehicles or other vacuum or suction actuated devices in connection with in-' actuated device depends, or to stall the en gine and put an end to the suction, and thus interefere also with the operation of the suction actuated device. Ithas also been found that the withdrawal of air from thesuction actuated device during the application of the brake mechanism for the purpose of preventing interference with'the operation of the engine, tends to retard the operation of the brake mechanism to a greater or less extent, and is therefore undesirable. The withdrawal of considerable quantities of air from a suction actuated device into the'manifold of the engine, is also likely to materially delay the startin of the engine. It is also to be understoo that in the operation of vacuum brake mechanism, the piston'ror other moving part of the suction actuated device is acted uponby differential pressures brought cient operation of the suction actuated d'e-.

about by producing a condition of rarefactlon on one side of the piston and admitting air on the other side, under the control of suitable reversing valve mechanism, and that the air so admitted -is thereafter necessarily withdrawn and delivered into the suction passage of the engine.

The object of our invention is to provide means in connection with a multi-cylinder internal combustion engine and a suction -actuated device or .devices operatively contnected therewith, whereby a quick and eflivice may be obtained, while the air with I drawn from the suction actuated device'and delivered into a suction passage of the engine is prevented from stalling the engine if idling, or materially interfering with the op eration thereof, and with theoperation of the suction actuated device, which depends upon the engine for its suction, and which consists in providing the engine with a plurality of independent carburetors, each of which is connected with a separate manifold section for independently supplying charges of explosive mixture to' certain cylinders only of the engine, and to provide in connection therewith, a suction actuated device comprising a cyllnder and piston,- which may be connected with brake mechanism-of the vehicle, for example, the operation of the cylinder on one side of the pistonbeing connectedat all times to one of said separate intake manifold sections 'by a suitable tubuinderon the other side of the piston being connected by a suitable tubular connection with another of said intake manifold sec 'tions under the control of-suitable valve mech anism which may be, for example, an ordinary two-way valve by means of which the a portion of the cylinderon one side of the I piston may be disconnected from its mani';

fold section and connected with the atmos- J phere to produce a power stroke of the piston y in a direction to apply the brake mechanism; v The valve mechanism may be turned intoa I position to disconnect the said portion of the cylinder both from the atmosphereand from the manifold section with which it is connected, to maintain the brakes applied, and may also be operated to re-connect it with saidmanifold section, to withdraw the. air Y 1 7 admittedto' operate the brake mechanism and equalize pressures on opposite faces of the piston, to effect an immediate release of the brake mechanism and permit it to return with the piston to retracted" position, under the influence of .the retracting springs with which the brakemechanism'is provided.

With this arrangement the air will be withdrawn fromv the actuator cylinder forward of the piston and delivered into one manifold section when the piston is 'in retracted fere with the operation of the cylinders connected with such manifold section, it would I position, and while it may somewhatinter- 75 lar connection, and the portion of the cylhave no effect whatever on the operation of other cylinders of the engine supplied by a different manifold section not connected in any way with the suction actuated device, and very little air would be withdrawn from the cylinder in rear of the piston into the manifold section connectedtherewith, so that the engine could be readily started and would be operated by the firing of the charges in cylinders not affected materially by the withdrawal of air from the suction actuated device, and the cylinder of the lat- I ter would beexhausted on both sides of the manifold sections not connected with the cylinder of the suction actuated device in rear of the piston. As the air is not simultaneouslywithdrawn from the suction actuated I device from both ends of the cylinder at the same time, our invention is applicable to a four cylinder engme, for example, having .two carburetors and two separate manifolds,

each supplying two cylinders, of the engine only. IVe prc 'erably,.however, desire to employ in carrying out our invention, an engine provided with more than two manifold sections, as for example, in the case ofa six -cylinder'engine, we prefer to employ three carburetors and three separate manifold sections, each supplying explosive charges to two cylinders, as in such case there will be at all times certain cylinders not connected with either end of the cylinder of the suction actuated device.

Our invention, may, however, be carried into effect in connection with a six cylinder engine forexa'mple, having two carburetors and two separate manifold sections, each supplying charges to three cylinders. In like manner, our invention may be carried out in connection with engines having 8, 1-2, 16., or more cylinders, in which separate carburetors and separate manifolds or manifold sections supply different groups of cylinders.

In the accompanying drawings, Fig. 1 1s a diagrammatic view showing an installation in an automotive vehicle comprising an internal combustion engine of the multi-cylinder type, brake mechanism for the vehicle, and vacuum or suction actuated power actuators for the brake mechanism and having our present invention embodied therein.

explosive i Fig. 2 is a detail sectional View of one form of valve mechanism which may be employed in carrying out our invention, showing it in the off position.

Fig. 3 is a similar view showing the valve in position to effect the power stroke of the.

I this instance provided withsix cylinders and having a plurality of intake manifold sections, each supplying a separate group of cylinders, and each manifold section being provided with aseparate carburetor. this instance we have shown the engine pro vided with three intake manifolds, 61, 62, 63,

each of which is connected with two cylin ders of the engine for supplying the explosive charges thereto. It will be understood that the engine might be provided with a single manifold divided into three separate sections, each communicating with its own carburetor and supplying charges to a group of cylinders, and the result would be exactly the same as hereinafter described. Each of the manifold sections shown is provided with a separate carburetor, the carburetors being indicated at 64, 65 and 66.

Each of the separate suction passages or intake manifold sections is provided with a separate throttle valve, the throttle valves being indicated at 67:, 68 and 69 respectively, and the throttle valves may be opcratively connected for joint operation from suitable control mechanism, as indicated in FigJ'l.

1 represents the cylinder of a suction or vacuum operated power actuator, adapted to be supported by the chassis of the vehicle. In this instance the cylinder is shown closed at-both ends by heads, 2, 2, and provided with a piston, 3, and piston rods, 5 and 6, extending through 0 )posite cylinder heads. One of the piston ro s, as the piston rod, 5, is operatively connected with brake mechanism for the vehicle-in any usual or desired manner. The brake mechanism may be of any preferred typeand may be applied to as manywheels as desired. In the present instance we have represented the brake mechanismof the vehicle diagrammatically in Fig. 1, as comprising abrake drum, 70, brake band, 71, brake applying lever, 72, provided with a retracting spring, 73, and

connected by'a link, 74, with the piston rod, 5, for purposes of illustration. In this instance we have shown 'a suction pipe, 26, connected with the cylinder forward of the piston therein and connected with one of the separate suction passages of the engine,

the manifold section, 62. 27 represents another suction pipe connected to'the' rear end) in detail in Figs. 2, 3 and 4, for purposes of.

illustrati on.- In this instance the valve com; prises-the valve casing, 28, provided with oppositely disposed suction ports, indicated at 29 and 30, and to which are connected portions of the suctlon pipe, 27, the portion of said pipe between. the valve and the manifold, 63, being given the reference numeral, 27*. The valve casingis also provided with air inlet port," 34, communicating with the atmosphere. 31 representsthe'rotary valve plug provided-with the assage, 32, extendmg diametrically throug the plug and normally connecting the two portions, 27 and 27, of the suction pipe in which the valve mechanism is located, the said plug being provided with a branch passage, 33, communicating with the central passage, 32, and

adapted to connect the section, 27, of the suction pipe, leading from the valve mecha. nism toothe cylinder in rear of the piston with the'atmospheric port, 34, 'when the. valve is turned into 'the position indicated in Fig. 3, for example, at which time-the section, 27', of .the suction pipe, leading from the valve mechanism to the intake manifold section, 63, will be closed. The valve plug is conveniently provided with a suitable handle, 40, for operating the same.- The suctlon pipe, 26, is preferably provided with a check valve, 35, and the portion,"27

of thesucti'on pipe, leading from the valve mechanism tothe manifold section, 63', is.

preferably provided with a check valve, 36, said check valves serving to normally maintain in the portions of the cylinder operatively connected therewith, the highest degree of rarefaction produced in the suction passage or manifold section with which each is connected, between operationsfof the actuator, and also to prevent any of the exlosive Imxture or motor fuel from passing into the cylinder of the actuator.

The valve mechanism controlling the'actu ato r is normally in the'position shown in F1g;--2, so that each suction pipe'connects one end of the actuatorcvlinder with one of' the intake manifold sections. The piston will at 73, which also holds the brake mechanism normally be in retracted position in close prox mity to one end of the cylinder, in

which position it'is held 'by-the retracting springs for the brake mechanism, indicated in released position. In starting the engine,

the air will be exhausted fromv the cylinder forward of the piston through the suction pipe, 26, and delivered intothe manifold section, 62, and the small quantity of air in .rear of the piston will be withdrawn throu h the-suctionpipe, 27, and discharged I into t e separate manifold section, 63. The withdrawal of the considerable quantity of air forward of the piston maytemporarilyf interfere with the operation of the cylinders supplied by the manifold section, 62, but the engine will start readily, as a comparatively small quantity of air will be discharged'intothe manifold section, 63, and where certain.

of the cylinders are supplied bymanifold section not connected with either end of the cylinder, as shown, for example, in Fig. 1,

the cylinders suppliedby that manifold section-will not be affected at all. The startin of the engine will, therefore, not be delaye by the exhaustion of air from the power actuator. .When the engine is running under normal cond1t1ons, and the actuator 1s not being operated, all the cylinders of the engine will receive their full chargesof explosive mixture without diminution or dilution and the air .having been exhausted from the cylinder on both sides of the piston,

the piston of the actuator is submerged in;

vacuum. To effect an operation of the actuator and an application of the brake mechanism, it is only necessar for the operator to rotate the plug, 31, of t e valve, by means ofthe handle or lever, 40, substantially aquarter. turn, thus cutting off the rear end of thecylinder from its source of suction, to wit, the manifoldfisection, 63, as indicated in Fig.3, and connecting the air' inlet or atmospheric port, 34, with theport, 29, thus connecting the cylinder in rear of the piston with the atmosphere. Air at once rushes into the cylinder in rear of the piston, building up pressure, andcausing-the piston to move in the direction of the arrow,-Fig.' l, to apply the brake mechanism. As the portion of the cylinder forward of the'piston is maintained in an exhausted condition, the actual operation of the brake mechanism will not discharge any materia-lquantity ofair into the intake manifold section, 62, with which it is connected, and the operation of the -en-..

gine' will not be affected, and there is no possibility of stalling the engine by the operation of the actuator to apply thebrake mechanism, as will-be readily seen. Even if some'air was withdrawn from the cylinder forward of the piston,- and delivered to the manifold section, 62, the engine. cylinders connected with the manifold section, 63, and

in this instance those connected with the manifold section, 61, will i not be affected, as no air would be delivered to either of said manifold sections from the actuator and the engine would continue to operate under any circumstances. 1

When the brakes have been' -applied to the desired extent, the plugvalve may be shifted to an intermediate position, -as indicated in Fig. 4, in whichthe portion of the cylinderbrakes as applied. By a further shift of the valve plug, 31, to its, normalposition, indicated in Fig. 2, the cylinder in rear 'of the piston will be again connected with its source of suction, and;the air admitted to apply the brakes will be withdrawn, immediately releasing the brakes and permitting them and'the piston of'the actuator-to be returned to normal position by the retracting spring, or springs, for the brake mechanism,- indicatedat 73. During the release of the brake mechanism and its return to normal position, air will be discharged into the intare manifold section, 63, but no air will be, discharged into the intake manifold section, 62, and of course'none will be discharged at any time into the manifold section,.61, if more than two manifold sections are provided. .In any case, the discharge of air into. the manifold section connected with the cylinder in rear of the piston during the return movement of thebrake mechanism and piston will not materially interfere with the operation of the engine, which will continue to operate as usual with the cylinders not connected with the manifold, '63.

It will be seen that ,in carrying our invention into effect, no restricting action is applied to the suction pipes or passages, and by normally maintaining the piston submerged in vacuum a quick application of the brake mechanism is effected, by simply connecting the cylinder in rear of the piston with the atmosphere and no retardation of the action of thepiston, whichmight other- Wise be caused by the factthat the actuator depends for the suction forward of the piston on the pumping action of a group of engine .cylinders and piston less. than the whole number, is avoided. If there is. any retardation of the action of the piston due to this cause, it will affect only the return movement of the piston when the brakes are released and return to normal position. This does not interfere with the highest efliciency of the brake mechanism, as the application of the brake mechanism will be extremely rapid and the withdrawal of even a small quantity of air from the cylinder in rear of'the piston will 'permit the immediate release of the brakes from their frictional contact.

It will be understood that in the operationof our invention, should sufficient air be admitted to the intake manifold section connected with either end of the cylinder, so as to interfere with the firing of the charges in the cylinders connected with that manifold section, the engine would continue to operate with the cylinders connected with the other, or other, manifold sections, and

as soon as the reverse movement of the piston occurs, the cylinders affected would resume firing even though the cylindersconnected with another manifold section might be affected sufiiciently to cause them to cease and from the other end of the cylinder Y into the other of said reservoirs, thus increasing the suction capacity available forir'the actuator, It will be apparent that the valve, 28 may control any desired number of power actuators, by providing the necessary pipe connections. By way of illustration we have shown a second actuator in Fig. 1 which may be located on the samevehicle, or' .a separate vehicle as a trailer, and connected with other .brake mechanism. This actuator comprises the cylinder, 101,- and piston, 103, having its piston rod, 105, connected with other brake mechanism, the

parts of which are indicated in the same manner as that previously described, and

given the same numerals with 100 added.

The pipe, 27, is provided with a branch pipe, 127, connected with the cylinder, 101, in rear of the piston and the suction pipe, 26, is provided with a branch pipe, 126, connected with the cylinder, 101, forward of the piston. These pipes are shown provided with cut off valves, 127 and. 126*, respectively, so that these pipes may be discern nected if desired, as where the cylinder, 101, is located on atrailer and it is desired to use the main vehicle without the trailer. -We

have also shown the pipes, 27 and 26, provided with additional branches, 227' and 226,

equipped with cut oif' valves, 227 and 226, as indicating that any desired number of power actuators can be connected inthe manner previously described and operated by a single valve mechanism.

Our invention also facilitates starting the engine, especially where more than 'oneactu ator is employed. When starting the engine v the pistons of the actuators will be in re tracted. position against one end plate of- "their respective cylinders, and most of the air contained in the cylinders will be on'the forward side of the pistons. Thisair will be withdrawn into one of the manifolds,

and while it may delay the starting of the cylinders connected therewith, it will not affect the starting of the cylinders connected with the other manifold or manifolds, and as only a very small amount of air is to be withdrawn from the actuator in rear of the piston, wl I ch passes to another manifold this 1 can be readily accomplished without niaterially delaying the starting of the cylinders connected with this manifold.

It will also be understood that although the pistons are maintained normally subless than the whole number thereof, a tubular connection from said cylinder on the -merged in vacuum, it is not a theoretical vacuum, but is a partial vacuum or rarification, averaging from 18 to 20 inches of mercury. Therefore a rapid application of the brakes, especially where a dplurality of actu ators are employed woul admit sufiicient air to affect the-engine char es in the manifold withwhich the forwar portions of the actuator cylinders are connected,- (by pipes, 26, 126; etc), and it is also obvious that where a plurality of actuators are used, a

far greater quantity'ofair must-be withdrawn from the actuator cylinders in rear of their pistons which would materially affect the engine charges in the manifold with which the saidportions of the actuator cylin- .municating with each of said suction passage, and a throttle valve for each of said passages, of a suction actuated device comprising a cylinder closed at both ends and a piston in said cylinder, a tubular connection extending from the cylinder onone side of the piston to certain of said suction passages other side of the piston therein tov certain other of said suction passages less than the whole number thereof, and controlling valve mechanism for the suction actuated device,

whereby the air withdrawn from said suction actuated device in the operation thereof is prevented from being discharged into the charges for all of the engine cylinders, to avoid stalling the engine, if idling.

2. The combination with a multi-cylinder internal combustion engine, rovided with a plurality of intake-manifol sections, each supplying explosive charges to separate cylinder, or cylinders, of the en ine, a separatecarburetor "for each of sai manifolds, a throttle valve interposed between each carfeet the operation of the engine or stall it buretor and its manifold, ofa suction actu ated device comprising a cylinder closedv at both ends, and a piston in said cylinder, a tubular connection extending from the said cylinder forward of the piston to certainof said manifold sections less than the whole number thereof, and connected thereto be tween the throttle valve, or valves, thereof,

and the engine cylinders, a tubular connection from said actuator cylinder in rear of the piston to certain other of said remaining manifold sections less thanthe whole numberthereof, and connected thereto between' the throttle valve, or.valves thereof and the engine cylinders, and. controlling valve mechanism for the suction actuated dGVlCt-Lf,

certain of said manifold sections being unconnected with the suction actuated device, whereby the withdrawal ofair from the suc-- tion actuated device will not materially afif idling. t v

3. The combination with a,.multi-cyl-inde I internal combustion engine provided with a i plurality of intake manifolds, each con: nected with-certain cylinders only of them-' gine, a separate carburetor-for each cylin- --der, and a throttle valve inter osed betweeneach carburetor and its niani old, ofax s'uc tion actuated device comprising a cylinder closed at both ends, a piston insaid cylinder, a tubular connection from said cylinder on one side of the piston to one only or said manifolds-between the throttle valve' and the engine cylinder or cylinders supplied thereof the suction actuated device on the oppo'-- site side of the piston with another" ofsaid manifolds between the throttle valve and the engine cylinder or cylinders supplied thereby, and controlling valve mechanism, for the suction actuated device, whereby the air withdrawn from the operation of the suc -jtion actuated device will be alternately delivered into said manifolds to prevent-the engine from stalling if idling.

4. The combination with a 'multi-cylinder internal combustion engine provided with-a pluralit of indepe en Suction Passag s;

each connected with certain onl offlthei'em.

gine cylinders, a separate car uretor for for each. of the'ffsai'n'e, of a power actuator comprising a cylinder closed atboth ends, a piston in said cylinder, at'ubula'r connection from said cylinderon oneside of'the piston therein to one of saidsuction passages be- .each of said passages, and 'a-throttle valve tween the throttle valve and the engine cylinder or cylinders supplied thereby, a. con 1 i nection fromsaid cylinder on the other side: of the piston therein to another of said'siiction passages between the throttle valve and the engine cylinder or cylinders supplied thereby, said engine having certain of said suct on passages unconnected with saidl'ac- 100 by, a tubular connection from saidcylinderf tuator cylinder, and controlling valve mechanism for the power actuator, whereby the operation of the power actuator is prevented from materially interfering with the opera-- separate passages, each of which supplies explosive charges to certain only of the engine cylinders, a separate carburetor connected with each of said suction passages, a throttle valve in eachof said suction-passages between the carburetor, and the; engine cylinder or cylinders supplied therebyfo f r EL piston submerged in vacuum, and provided a power actuator including a cylinder close at both ends, a piston in said cylinder operatively connected with brake mechanism for the vehicle, retracting means for said brake mechanism'andpiston, a tubular connection from said actuator cylinder forward of .the piston to certain of said suction passages of the engine less than the whole number between the throttle valve thereofpand the engine cylinder or cylinders supplied thereby, a tubular connection from said actuator cylinder in rear of the piston and certain other of said suction passages between the throttle valve therefor and the engine cylinder or cylinders supplied there by, whereby said actuator piston is normally maintained submerged in vacuum,. and means for disconnecting the actuator cylinder in rear of the piston from its source of suction and admitting atmospheric/fair to apply the brake mechanism without admitting material quantities of air into the suction passage connected with the actuator cylinder forward of the piston and for re-connecting the actuator cylinder in rear of its piston with its source of suction to withdraw the air previously admitted and permit the release of the brake and the return of the brake mechanism and piston to retracted position without admitting air to the other suction passage connected with the cylinder, whereby material interference with the operation vof the ensaid cylinder operatively connected with.

brake mechanism of the vehicle, yielding reand' piston, a tubular connection from the actuator cylinder forward of its piston to one of said suction passages between the throttle valve and the engine cylinder or cylinders supplied thereby, a tubular con nection from the actuator cylinder in rear of the piston to anotherof said suction passages between the throttle valve therefor and the engine cylinder or cylinders supplied tracting means for said brake mechanism a thereby, and controlling valve mechanism 1 in said last mentioned tubular connection,

normally maintaining'the actuator cylinder in rear of the piston in communication with the suction passage withwhich it is connected,,to normally maintain the actuator with means for disconnecting the said portion of. the actuator cylinder from said suction passage and connecting it with the atmosphere to effect a power stroke of the tuator cylinder in rear of the piston from its source of suction and from the at- Y Y mosphere to maintain the brakes as applied, said valve mechanism being movable into a position to re-connect said portion of the actuator cylinder with its source of suction to withdraw the air previously admitted and permit the brakes to release-them selves without discharging the air into the suction passages not connected with said portion of the actuator" cylinder, whereby the engine will be prevented from stalling if idling.

7. In brake mechanism for automotive 1 vehicles, the combination with a multi-cylinder internal combustion engine provided with a plurality of suction passages, each supplying explosive charges to certain only of the engine cylinders, a separate carburotor for each of said suction passage, a throttle valve in each of said suction passages between the carburetor and the cylinder or cylinders supplied thereby, of, a plurality of power actuators each comprising a cylinder closed at both ends, and apiston in said cylinder operatively connected with brake mechanism, yielding retracting means for said brake mechanisms and pistons, tubular connections from one of sai suction assages, between the throttle""valve and t e engine cylinder or cylinders supplied thereby, to each of the actuator cylinders forward of its piston, tubular connections from another of said suction passages between the throttle valve therefor and the enginecylinder or cylinders supplied thereby and each of said actuator cylinders in rear of its piston, and controlling valve mechanism for said lastmentioncd tubular connections for controlling all of said actuators simultaneously constructed to normally maintain the actuator cylinders in rear of their pistons in communication with the suction passage with which they are connected and the actuator pistons submerged in vacuum, and to disconnect said portions of the actuator cyli'nders from said suction passage and conncct them with the atmosphere to effect power strokes of the actuator pistons to apply the brake mechanisms without discharging appreciable quantities of air into the suction passage connected with the actuator cylinders forward of their piston, and to reestablish communication between the portions of the actuator cylinders in rear of their pistons with the suction passage connected therewith to withdraw the air previously admitted and permit the brake mechanisms to release themselves without discharging the air not connected with said portions of the actuator cylinders, whereby the engine will be prevented from stalling,

if idling.

8. In brake mechanism for automotive vehicles, the combination with a multi-cylinder internal combustion engine provided with a-plurality of intake manifold sections each supplying explosive charges to sepa rate cylinder or cylinders of the engine, a separate carburetor for each of said manifolds, a throttle valve interposed between each carburetor and its manifold section, of a power actuator comprising a cylinder closed at both ends, and a piston in said cylinder operatively connected with brake meclianismof the vehicle, retracting means for said brake mechanism and piston normally maintaining the piston adjacent to one end of the cylinder, a tubular connection extending from the cylinder forward of the piston to certain of said manifold sections less than the whole number thereof,

and connected thereto between the throttle valve or valves thereof and the engine cylinders, a tubular connection from said cylinder in rear of the piston to certain other of said remaining manifold sections, and controlling valve mechanism in said last mentioned tubular connection, normally maintaining the actuator cylinder in rear of the piston in communication with the manifold section or sections with which it is connected and constructed to disconnect it therefrom and place it in communication with the atmosphere, whereby when the motor is started with the brakes released the small amount of air in rear of the actuator piston will be readily withdrawn-and the engine cylindersconnected with certain indcr-forward of the piston is connected may be delayed in starting by reason of the large amount of air to be withdrawn from the said portion of the actuator cylinder.

9. In brake mechanism for automotive vehicles, the combination with a multi-cylindcr internal combustion engine, provided with a plurality of suction passages, each of which supplies explosive charges to certain only of the engine cylinders, a separate carburetor for each suction passage, a throt tle valve in each suction passage between the carburetor and the engine cylinder or cylinders supplied thereby, of a plurality of power actuators each comprising a cylinder closed at both ends and a piston in said cylinder operatively connected with the brake mechanism, yielding retracting meansfor said brake mechanisms and piston, normally holding each pis ton adjacent to the rear end of its cylinder, tubular connections for connecting one of said suction passages between its throttle valve and the engine cylinder or cylinders supplied thereby with each actuator cylinder forward of its piston, tubular connections from. another of said passages between the throttle valve therefor and the engine cylinder or cylinders supplied thereby and each actuator cylinder in rear of the piston therein, and controlling valve mechanism for said last mentioned tubular connections normally maintaining the actuator cylinders in rear of their pistons in communication with the suction passage to which they are connected, and the actuator pistons submerged in vacuum, and provided with means for disconnecting said portions of the actuator cylinders from said suction passage and connecting them with.

natures.

CALEB S. BRAGG. VICTOR W. KLIESRATH.

Images