US1801483A

US1801483A - Power actuator

Info

Publication number: US1801483A
Application number: US132366A
Authority: US
Inventors: Caleb S Bragg; Victor W Kliesrath
Original assignee: Bragg Kliesrath Corp
Current assignee: Bragg Kliesrath Corp
Priority date: 1925-01-05
Filing date: 1926-08-30
Publication date: 1931-04-21
Anticipated expiration: 1948-04-21
Also published as: GB245444A; GB260967A; DE549177C; FR609218A; FR631643A; US1848000A; US1872660A; DE518737C; US1826416A

Description

Apil 21, 1931. C, s, BRAGG ET AL LSMASB POWER AGTUATOR` Original Filed Jan. 5, 1925 ATTORNEY patented pr. 21, 1931 UNTED STATES anni OALEB S. BRAGG, 0F PALM BEACH, FLORIDA, AND VICTOR W. KLIESRATH, OF PORT WASHINGTON, NEW YORK, ASSIGNORS LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK T0 BRAGGKLIESRATH CORPORATION, OF

POWER ACTUATOR Original application filed January 5, 1925, Serial N'o. 506. Divided and this application led August 80,

1926. Serial Our invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate several embodiments of the same, selected by us for purposes of illustration, and the said invent-ion is fully disclosed in the following description and claims.

This application is a division of our former application filed January 5, 1925, and given Serial No. 506. l

Our invention relates to a power actuator, adapted especially for use in connection with automotive vehicles propelled by an internal combustion engine, and most conveniently operated by suction from a suction`y passage of the engine between thethrottle valve and the engine cylinder, or cylinders, as for example, by means of alconnection with the intake manifold of the engine. In rior application for Letters Patent of the nited States filed December 22, 1923, Serial N o. 682,346, We have disclosed a` power actuator of this general type connected with the intake manifold of the internal combustion engine by means of a pipe or passage in which are located an adjustable regulating valve or other restricting means, a check valve, and a storage space, or tank, and comprising a cylinder, a double acting piston therein, and reversing valve mechanism for applying differential pressures on opposite faces of the piston, and said actuator being combined with a foot lever, or other operator operated part, and with a brake mechanism or other part to be actuated in such manner that the latter can. be operated by the actuator-under the control of the foot lever while the operator may add his physical power to the power of the actuator when desired, or in case of failure of the actuator, may positively operate the actuatedn part by physical power applied to the foot lever, or other operator operated part.

- The regulating valve or other restricting device prevents such large volumes of air being drawn into the intake manifold as to be likely to dilute the explosive charges passing therethrough, so as to stall the engine When idling while the storage space or storage tank provides a large space in which a partial vacuum or rarification is maintained at all timeskwhile the engine is running, by withdrawing the air therefrom in comparatively small quantities, and insures the instantaneous vwithdrawal of the necessary amount of air from the actuator cylinder when the reversing valve mechanism is moved to open position, to insure the instantaneous and effective operation of the actuator.

According yto our invention, we dispense with any extraneous storage space or storage tank in the suction line extending to the intake manifold exterior to the actuator cylinder, and maintain a condition of partial vacuum or rarication Within the acuator cylinder itself, on both sides of the piston, which is made to supply the necessary storage space. Thereby We Vobtain a number of important and advantageous results in the construction, installation and operation of the power actuator. Inv the first place, the tank, which is a bulky element, is entirely done away with and the construction is correspondingly simplified and rendered less expensive. As a partial vacuum is maintained within the actuator cylinder on both sides of the piston therein when the device is in normal or inoperative position, when the reversing valve mechanism is moved into a position to effect the operation of the actuator, one end of the cylinder'on one side of the piston is connected with the intake manifold or other vacuum producing means, the other end of the cylinder on the other side of the piston being connected with the atmosphere, and the immediate result is that the atmospheric air rushed into the end of the cylinder to which it is admitted, and effects `the operation of the piston in the desired direction and to the desired extent without any appreciable quantity of air being actually withdrawn from the cylinder and admitted to the intake manifold or other suction means, thereby eliminating the drop in the suctionor rarication, which would result were the cylinder full of air and this air admitted during the application of the brakes. The maximum suction is therefore immediately available. The restricting valve properly adjusted to prevent stalling the vmotor While idling would restrict the passage of this air over some eX- tended time, thereby delaying the exertion of the full force of the vacuum, where our present invention is not employed. The air admitted on the other side of the piston is not being withdrawn until the valve mechanism is reversed and the piston is moved in the opposite direction. This is particularly advantageous in the application of the actuator to the brake mechanism of automotive vehicles such as automobiles, trucks and motor buses, for example, as when the brake is applied the actuator is operated without any material admission of air to the intake manifold and therefore without any possibility of injuriously affecting the explosive mixture or of stalling the engine, and when the valve mechanism is reversed to efect the release of tle brakes, by operating the piston in the opposite direction, the atmospheric air admitted for the purpose of obtaining the previous application of the brakes can be gradually withdrawn to the intake manifold, under the control of the regulating valve, so as to prevent interference with the operation of the engine, while securing the effective release of the brake mechanism. lf the motor should stall due to the admission of this air when the brakes are being released, it would be a matter of far less importance than the stalling of the motor when the brakes are being applied. It is not so important that the movement of the piston in a direction to release the brakes shall be as rapid as the movement of the piston in the direction to apply the brakes. As a matter of fact, a very slight movement of the piston in the direction to release the brakes would be sufficient to release them, and for this reason continued application and releasing of the brakes without allowing the piston to come to the at rest position may be effected with com paratively small amount of air being drawn into the intake manifold., and the piston may be permitted to return to itc normal position after an application of the brakes more slowly than it would be desirable to have it moved in the opposite direction. Furthermore when the piston comes to the at rest position after an application of the brakes, there is a partial vacuum in the rear of the cylinder. Therefore, the only air to be exhausted is the amount admitted to the forward end of the cylinder to effect the releasing ofthe brakes, which is considerably less than the total amount of air that could be contained in the cylinder, were it not for our invention, which continually keeps at least one end of our cylinder under vacuum, the total amount of air in the cylinder would have to be exhausted after each operation of the brakes.

Our invention therefore enables us to simplify and decrease 'the cost of the apparatus, and at the same time insures most efficient leonesa operation of the actuator without prejudice to the continuous and efficient operation of the internal combustion engine from the suction passage of which the necessary power or suction for the operation of the actuator is derived.

In our former application above referred to, these features are broadly claimed together with one of the specific embodiments for carrying our invention into eifect, and the present application is directed to another specilic embodiment for carrying the invention into elfect disclosed in our previous application above referred to, but not specific ally claimed therein, but which is specifically claimed in this specication.

Referring to the accompanying drawings,

Fig. l represents a diagrammatic view of an installation in which our improved power actuator is connected with the internal combustion engine of an automotive vehicle for the operation of the brake mechanism thereof.

Fig. 2 is an enlarged sectional view illustrating one form of our improved actuator embodying our present invention, a portion of the piston rod and valve actuating sleeve being broken away and showing the piston in normal retracted position.

Fig. Q- is a detail sectional view of the terminal portions of the piston rod and valve actuating sleeve omitted from Fig. 2.

ln Fig. l of the accompanying drawings, we have shown diagrammatically an installation suitable for use in an automotive vehicle in which one of our improved actu* ators is shown as interposed in the connections between a foot lever, 88, and brake mechanism for the vehicle, diagrammati-A ternal combustion engine for propelling the' vehicle, and provided with an intake manifold, indicated at (il, and communicating with the carburetor, Gla, to which is connected a pipe, 62, between the throttle valve indicated at 61D, and the engine cylinders, in which pipe are located preferably an adjustable regulating valve, or restricting valve, 64, a check valve, 65, and a vent valve, 67, normally closed and opening outwardly. The pipe, 62, communicates with one of our improved power actuators, the cylinder of which is indicated at 201 in Fig. l, the said pipe having a flexible portion connected to a hollow valve actuating sleeve, indicated at 220, and communicating with the reversing valve mechanism. The sleeve, 220, is connected by a link, 85, with the foot lever, 88, which is provided with the usual retracting spring, 89, and the piston rod, 205, of the Leonesa actuator is connected by a link, 73, with the brake lever, 72.

In Figs. 2 and 2a, we have shown one form of our improved actuator embodying our present invention. In this figure, 201 represents the actuator cylinder closed at both ends by heads, 202, connected by bolts indicated at 202a, in Fig. 1, or otherwise. 203 represents the double acting piston provided with oppositely disposed gaskets, 204. 205 represents a hollow piston rod which extends through `a stufiing box, 206, in one end of the cylinder, and is connected at its inner end with the piston, 203. The hub, 210, of the piston is provided with two valve chambers, 211 and 212 respectively, each of which is provided with two valve seats preferably conical and coaxial with the axis of the piston. The valve chamber, 211, is provided with seats, 213 and 214, and the valve chamber, 212, is provided with valve seats, 215 and 216. The piston hub is provided with an outlet chamber or suction chamber indicated at 217, which communicates with each of the valve chambers through the valve seats, 214 and 215. The piston hub is also provided with a higher pressure chamber, 218, in this instance communicating 1 with the a-tmosphere and with the valve seat, 216, and bv a lateral passage, 219, with the valve seat, 213. Thevvalve actuating part, in this instance, a hollow sleeve, 220, passes through a stufhng box, 221, in the cylinder head at,the opposite end of the cylinder from the stuiiino box, 206, the said sleeve extending longitudinally through the piston hub and valve chambers, and through the hollow pistonrod, 205, and being longitudinally movable to effect the operation of the reversing valves. The valve sleeve may be made convenientlyv in two parts, 220 and 2205, if desired, and as herein shown in provided with a pair of oppositely disposed poppet valves in each valve chamber, the said valves being preferably formed of molded rubber and frictionally engaging the sleeve, so that the sleeve may move through the valve while forming an air-tight joint therewith. The valves are indicated at 240, 241, 242 and 243, the

valves

241 and 242 being suction valves, and the valves, 240 and 243 being air inlet valves. The valves are yieldingly held in engagement with their seats, preferably` by a yielding cushioning device interposed between -the pairs of valves, and indicated at 250. The actuating sleeve is provided with suitable means for opening one valve of each pair when the sleeve is moved in either direction. In this instance, the sleeve is shown provided with a collar, 222, located between the suction valves, 241 and 242, and adapted to operate either of said valves, and the sleeve is also provided with the collars, 231 and 232, mounted on the valve sleeve outside of the air inlet valves, 240 and 243 respectively, for

plication for Letters-Patent of the United States, filed November 22, 1924, and given Serial No. 751,481.

In the form of our invention illustrated in Figs. 2 and 2B, the central collar, 222, in the vacuum chamber, 217,. which actuates the suction valve, is so located with respect to a stop, in this instance formed by a shoulder, 226% on the fitting, 226, which engages the adjustable follower, 221", of the stufling box, 221, when the parts are in normal retracted or off position, that when the piston is arrested by the engagement of its nnb with the opposite end of the cylinder, the valve actuating sleeve, 220, will hold the suction valve, 242, slightly oli1 its seat, as shown in Fig. 2, thereby placing the cylinder in rear of the piston in communication with theuction chamber through a port or ports, 235, which connect the valve seat, 215, with that portion of lthe cylinder. The other suction calve, 241 being seated, the ports, 234, which connect its valve seat, 214, with the forward portion .of the cylinder are closed. In this instance, we have shown an auxiliary passage, 242, extending from the valve seat, 215, through the piston to the forward side thereof, (to the left in Fig. 2). This passage may be made conveniently by drilling the piston with a drill of small diameter, so that the passage of air therethrough will not be suiiiciently rapid to interfere with the operation of the piston to restore it to retracted or off position (to the right in Fig. 2), when the valve, 242, is opened for that purpose. This auxiliary passage will, however, permit the `air within the cylinder forward of the piston to be exhausted to the manifold during the period when the parts are in retracted or off position, so that the piston will be submerged in vacuum when lin retracted position. Y v

It follows from this construction that as soon as the engine is started, the suction produced in the intake manifold will yexhaust the air from vthe cylinder of the actuator on both sides of the piston maintaining it submerged in vacuum. If now it is desired to apply the brakes, the foot lever is actuated to move the sleeve, 220, in the direction of the arrow in Fig. 2, thereby permitting the suction valve, 242, to close, and subsequently Cit opening the suction valve, 241, and the air inlet valve, 243. This connects the cylinder forward of the piston with the suction chamber, 217, and admits atmospheric air in rear of the piston, moving the piston forward in a direction to apply the brakes, but no appreciable amount of air will be drawn into the intake manifold through the pipe, 62, as the portion of the cylinder forward of the piston is already exhausted. The forward movement of the piston will follow any eX- tent of the forward movement of the brake lever, 88, and when the movement of the brake lever stops, the piston will continue to move forwardly until the air inlet valve, 243, closes, so as to hold the piston and brakes. lVhere continued applications of the brakes are desired, a slight release of the foot lever producing a slight rearward movement of the valve sleeve will open the suction valve, 242, and connect both ends of the cylinder with the suction passage, 217, producing a partial or entire equalization of pressures on opposite sides of the piston, which will instantly permit the brakes to relieve themselves, under the action of their retracting means, as spring, 74, slightly retracting the piston. A slight forward movement of the pedal lever will again admit air in rear of the piston, and connect the cylinder forward of the piston with the suction chamber, and a number of' successive applications of the brake can be made without admitting material quantities of air into the intake manifold. W'hen the foot lever, 88, is released, the retraeting spring, 89, will move the valve, 220, in a direction opposite that indicated by the arrow in Fig. 2, and the suction valve, 241, will be forced to its seat by the cushioning device, and the reversed movement of the sleeve, 220, under the action of the retracting spring, 89, of the foot lever, will open the suction valve, 242, connecting the cylinder in rear of the piston witlrthe suction chamber, and the air inlet valve, 240, will be opened admitting atmospheric air to the Cyliuder forward of the piston through the opening, 283, controlled by said valve, thus returning the piston to normal retracted position, illustrated in Fig. 2, the piston being arrested by engagement with the end of the cylinder, and the valve actuating sleeve being arrested by the engagement of the shoulder, 22(51, with the follower, 2211. Vhen the parts come to rest, the suction chamber, 217, will therefore be in communication with the cylinder in rear of the piston by reason of the unseated position of the valve, 242, and will also be connected with the cylinder vforward of the piston b v the auxiliary passage, 24211, equalizing the pressures on opposite sides of the piston, and the air previously admitted to effect the reverse movement of the piston, will be exhausted. from the cylinder, producing rarilication on both sides ofthe piston.

The exhaustion of air from the cylinder, therefore, only takes place during and after the return stroke of the piston, and the air exhausted from the cylinder is delivered gradually to the intake manifold by properly regulating the restricting valve, (54, in the pipe, 62, so that the operation of the engine will not be interfered with, and the eduction of the air r'nay be retarded as much as desired, as the first movement of the piston rearwardly will relieve the pressure of the brakes, and it is not important that the piston should move rearwardly as quickly as it moves forwardly to apply the brakes. The withdrawal of the air may, therefore, be distributed over a great or less )eriod of time, according to the `adjustment of the valve, 64, so as to avoid the undue dilution of the eX- plosive charges or the feeding of too small an amount of hydrocarbon fuel, and the piston is left submerged in vacuum and ready for immediate and effective operation to apply the brakes at any moment. As the degree of suction in the suction passages of the engine varies from time to time, we interpose the check valves, G5, in the pipe, 62, so that after the cylinder is subjected to the great est amount of suction, the condition 0f rariiication so produced will remain, and as the brakes are usually operated at intervals, the greatest possible rarification will ordinarily exist in the cylinder of the actuator at all times, ready to ell'ectively apply the brakes in the manner before described.

We prefer to connect the valve actuating sleeve, 220-220, with the piston b means providing for a limited amount of iost motion, suiiicient to permit the operation of the valves, so that after this lost motion is taken up, the physical power of the operator can be directly applied to the piston and the brake mechanism connected therewith, to enable the operator to add his physical force to that of the actuator, or to operate the brakes by his physical force alone if the power should fail for any reason, the lost motion permitting the movement of the valves in any case, and serving when power fails to vent the cylinder. In the present instance, as shown in Fig. 2, the section, 220, of the valve sleeve is provided with a recessed portion, 220", and a collar, 220, and a piston rod, 205, is in this instance provided with set screws, 205, eX- tending into said recess (or recesses) 220", so that when thesleeve is moved forward by the foot lever to apply the brakes, and the piston has followed, applying the brakes to the full capacity of the actuator, the operator may be pushing the foot lever, 88, further forward until the rear edge of the recess, 220", engages the screws, 205, apply his physical force to the piston and brake mechanism in addition to the power of the actuator. It also follows from this construction that the operator, should the power of the actuator fail, may apply the brakes directly. The first forward movement of the valve actuating sleeve will set the valvesso as to vent the cylinder forward of the piston, and admit air in the rear of the piston, to permit this movement. On the release of the foot lever, the reti-acting spring, 89, will shift the valve sleeve rearwardly, so as to vent the cylinder (in case of failure of power), and the forward end of the recess, 220D, will engage the sct screws and move the piston rearwardly to release the brakes and restore the parts to 0H position. The check valve, 65, shown in Fig. 1, and interposed in the suction pipe, insures the exhaustion of the cylinder on bot-h sides of the piston to the greatest eXtent permitted at any time by the operation of the engine by the manipulation of the throttle valve, while the vent valve, 67a, shown in Fig. l, provides for the venting otthe cylinder should the motor stop, or the suction fail at any time, and should it become necessary for the operator to apply the brakes physical power.

What we claim and desire to secure by Letters Patent is 1. In a power actuator, the combination of a cylinder closed at both ends, a piston in said cylinder and yielding retracting means operatively connected therewith, means for establishing differential pressures on opposites faces of said piston including controlling valves located in the piston, an operator operated part, operative connections therefrom to said controlling valves, said piston being provided with a passage for connecting the portions of the cylinder on opposite sides of the piston controlled by one of said valves for equalizing pressures between the portions of the cylinder on opposite sides of the piston, when said valve is in open position.

2. `In a power actuator, the combination of a cylinder closed at both ends, a piston in said cylinder and yielding retracting means operatively connected therewith, means for establishing differential pressures on opposite faces of said piston including controlling valves located `in the piston, an operator operated part, operative connections therefrom to said controlling valves, said piston A being provided with a passage for connecting the portions of the cylinder on opposite sides of the piston controlled by one of said valves for equalizing pressures between the portions of the cylinder on opposite sides of the piston, when said valve is in open position, and means for holding the said valve in open position when the piston is in retracted position.

3. In a power actuator, the combination of a cylinder closed at both ends, a piston therein and yielding retracting means connected therewith, means for establishing differential pressures on opposite `faces of the piston including an air inlet passage, a suction passage, and controlling valve mechanism for the actuator comprising air inlet and suction valves for controlling said passages located in the piston, an operator operated part, connections therefrom to said valves, said actuator being provided with a passage in the piston controlled by a suction valve of said controlling valve mechanism, for connecting portions of the cylinder on opposite sides of the piston with each other and with said suction passage, when the said controlling suction valve is in open position.

4:. In a power actuator, the combination of a cylinder closed at both ends, a piston therein and yielding retracting means connected therewith, means for establishing differential pressures on opposite faces of the piston including an air inlet passage, a suction passage, and controlling valve machanism for the actuator comprising air inlet and suction valves for controlling said passages located in the piston, an op-erator operated part, connections therefrom to said valves, said actuator being provided with a passage in the piston controlled by a suction valve of said controlling valve mechanism, for connecting portions of the cylinder on opposite sides of the piston with each other and with said suction passage, when the said controlling suction valve is in open position, and means for maintaining the said controlling suction valve in open position when the piston is in retracted position, to maintain' the piston submerged in vacuum.

5. ln a power actuator, the combination of a cylinder closed at both ends, a piston in said cylinder and yielding retracting means operatively connected therewith, means for establishing differential pressures on opposite faces of the piston including an air inlet passage, a suction passage, and controlling valve mechanism for` the actuator comprising suction and air inlet valves controlling said passages, and provided with valve seats, an operator operated part, comiections therefrom to said controlling valve mechanism, said piston being provided with an auxiliary passage therethrough, terminating at one end in a valve seat for a suction valve of said controlling valve mechanism, for connecting the portions of the cylinder on opposite sides of the piston with each other and with the suction passage, when the said valve is in open position.

6. ln a power actuator, the combination of a cylinder closed at both ends, a piston in said cylinder and yielding retracting means operatively connected therewith, means for establishing differential pressures on opposite faces of the piston including an air inlet passage, a suction passage, and controlling valve mechanism for the actuator com rising suction and air inlet valves controiling said passages, and provided with valve seats,

an operator operated part, connections therefrom to said controlling valve mechanism, said piston being provided with an auxiliary passage therethrough, terminating at one end in a valve seat for a suction valve of said controlling valve mechanism, for connecting the ortions of the cylinder on opposite sides of t e piston with each other and with the suction passage, when the said valve is in open position, and means for maintaining said suction valve in open position when the piston is in retracted position, to maintain the piston submerged in vacuum.

:17. In a power actuator, the combination with a cylinder, closed at both ends, a. double acting piston v insaid cylinder and yielding retracting means operatively connected therewith, a reversing valve mechanism including'a'vacuum chamber and suction passages extending therefrom to the cylinder on both sides of the piston, an air inlet passage, and passages for connecting it with the cylinder on both sides or the piston, and valves for controlling said'suction and air inlet passages, a vacuum producing means connected with said vacuum chamber, means tor holding one of said suction valves unseated when the piston is in retracted position, the piston being provided With a passage ltherethrou h, for connecting the portions of the cylin er on opposite sides of the piston, said passage beingmaintained in open condition While said suction valve is unseatedn 8. In a power actuator', the combination with a cylinder closed both ends, a double acting piston in said cylinder yielding retracting means operatively connected therewith, a reversing valve mechanism including a vacuum chamber and suction pas sages extending therefrom to the cylinder on both sides of the piston, an air inlet passage, and passages for connecting said inlet passage with the cylinder on both sides of the piston, and valves for controlling said suction and air inlet passages, a vacuum producing means connected with said vacuum i chamber, said piston being provided with an sage with the cylinder both s..

auxiliary passage therethrough, terminating at one end in the seat for the suction valve controlling the connecting passage to the portion of the cylinder in rear of the piston, for connectin the portions ci the cylinder on opposite sides of the piston with each other end with the suction passage, when the said suction valve is in open position.

9. In a power actuator, the combination with a cylinder closed at both ends, a. double acting piston in said cylinder and yieldinfr retraeting means operatively connected therewith, areversing valve mechanism including a vacuum chamber and suction passages extending therefrom to the cylinder on both sides ol the piston, an air inlet passage, and passages for connecting said inlet pasrcs the piston, and valves for controlling said suction and air inlet passages, a vacuum producing means connected With said vacuum chamber, said piston being provided with' an auxiliary passa e therethrough, terminating at one end in Vt ie seat for the suction valve controlling the connecting passage to the portion of the cylinder in rear of the piston, for connecting the'portions of the cylinder on opposite sides of the piston with each other and with the suction passage, by the opening of said suction valve, and means for holding the said suction. valve unseated Whenthe piston is in retracted position, to maintain the piston subnier ed in vacuum.

10. In a power actuator, t e combination of a cylinder closed at both ends, a piston therein and yielding retracting means operatively connected therewith, reversing valve mechanism located in the piston and including an outlet chamber, passages connecting said chamber' With the cylinder on both sides of the piston, an inlet chamber for higher pressure fluid, passages connecting said inlet chambery With the cylinder on both sides of the piston, outlet and inlet valves controlling said passages, yielding means for normally holding all of said valves seated, said piston being provided with an auxiliary passage controlled by one of said outlet valves for connecting ortions of the cylinder on opposite sides oiD the piston with each other and with said out-let chamber, when the said outlet valve is in open position, an operator operated part connected operatively with said inlet and outlet valves, and means i'or holding the outlet valve controlling said auxiliary passage in open position when the piston is in retracted position.

l1. In a power actuator, the combination of a cylinder closed at both ends, a piston therein and yielding retracting means operatively connected therewith, reversing valve mechanism located in the piston and including an outlet chamber, passages connecting said chamber with the cylinder on both sides of the piston, an inlet chamber for higher pressure fluid, passages connecting said inlet chamber with the cylinder on both sides oi?` the piston, outlet and inlet valves controlling said passages, yielding means for normally holding all of said valves seated, said piston being provided with an auxiliary passage controlled by one of said outlet valves for connecting portions of the cylinder on opposite sides of the piston with each other and With said outlet chamber, when the said outlet valve is in open position, a valve operating part provided with means for operatively engaging said outlet and inlet valves, means for arresting said valve operating part in position to hold the outlet valve controlling said auxiliary' passage in open position when the piston is in retracted poaeoaaes both sides of the piston, suction and inlet,

valves controlling said passages, and yielding means normally tending to seat said valves, said piston being provided with an auxiliary passage therethrough controlled by one of said suction valves for connecting portions of the cylinder on opposite sides of the piston with each other and with said suction passa-ge, of a suction pipe connecting the suction chamber with the suction passage of the engine, means for connecting the actuator pistonavith a part to be operated, yielding retracting means for said piston and part to be operated, and an operator operated part operatively connected with said suction and inlet valves.

13. ln an automotive vehicle provided with an internal combustion engine having a suction passage, the combination with a power actuator comprising among itsmembers a. cylinder closed at bothends, a piston therein, reversing valve mechanism located in the piston, including a suction chamber, passages connecting it With the cylinder on both sides of the piston, an air inlet chamber, passages connecting it with the cylinder on both sides of the piston, suction and inlet valves controlling said passages, and yielding means normally tending to seat said valves, said piston being provided with an auxiliary passage therethrough controlled by one of said suction valves for connecting portions of the cylinder on opposite sides of the piston with each other and With said suction passage, of a. suction pipe connecting the suction chamber with the suction passage of the engine, an operator operated part connected with said inlet and suction valves, means for holding the suction valve controlling said auxiliary passage in open position when the piston is in retracted position, means for connecting the actuator piston with a part to be actuated and yielding means for retracting said piston and part to be actuated.

14. In an automotive vehicle provided with an internal combustion engine having a suction passage, the combination with a power actuator comprising among its menibers a cylinder closed at both ends, a piston therein, reversing valve mechanism located in the piston, including a suction chamber, passages connecting it with the cylinder on both sides of the piston, an air inlet chamber, passages connecting it with the cylinder on both sides of the piston, suction and inlet valves controlling said passages, and yielding means normally tendine to seat said valves, said piston being provided with an auxiliary passage therethrough controlled by one of said suction valves for connecting portions of the cylinder on opposite sides of the piston with each other and with said suction passage, of a suction pipe connecting the suction chamber With the suction passage of the engine, a valve actuating part extend ing through the inlet and suction valves and provided with means for operatively engaging them to open one inlet valve and one suction valve When moved in either direction,

'an operator operated part connected With the valve actuating part, means for arresting the valve controlling said auxiliary passage in open position when the piston is in retracted position, means for Yconnecting said piston with a part to bc actuated, and yielding means for retracting the part to be actuated and said piston.

15. ln an automotive vehicle provided with an internal combustion engine, having a suction passage, and brake mechanism for the vehicle, the combination with a power actuator comprising `among its members a cylinder closed at both ends, a double acting piston in said cylinder, reversing valve mechanism located in said piston and including a suction chamber, passages connecting it with the cylinder on both sides of the piston, air inlet passages communicating with the cylinder on both sides of the piston, suction and air inlet valves controlling said passages, yielding means normally tending to seat said valves, said piston being provided With an auxiliary passage extending therethrough, terminating at one end in the valve seat for one of the suction valves, and adapted to connect the` portion of the cylinder on both sides of the piston with each other and with the suction chamber when said suction valve is unseated, of a suction pipe for connecting said suction chamber with the suction passage of the engine, a valve actuating part extending through said valve and to the exterior of the cylinder, and provided with meansy for engaging said valves to open one inlet and one suction valve When moved in either direction with respect tothe piston, an operator operated part connected With the valve actuating part, means for connecting the piston with the brake mechanism of the vehicle, yielding means for retracting the brake mechanism and piston, and means for arresting the valves actuating part in position to hold unscated the suction valve controlling said auxiliary passage When the piston is in retracted position.

16. ln an automotive vehicle provided with an internal combustion engine, having a suction, passage and brake mechanism 'for the vehicle, the combination ivith a power actuator comprising among its members a cylinder clbsed at both ends, a double acting piston in said cylinder, reversing valve mechanism located in the piston and including a suction chamber, passages connecting it with the cylinder on both sides of the piston, air inlet passages for the cylinder, and suction and air inlet valves controlling said passages, yielding means normally tending 'to seat said valves, a valve actuating part movable with and with respect to the piston, an operator operated part connected with the valve actuating part, said valve mechanism being constructed so that a/movement ot the valve actuating part in cithei1 direction with respect to the piston will eliect an actuation of the piston in the same direction, said piston being provided With an auxiliary passage extending therethrough and controlled by one of said suction valves, and adapted to connect the portions of the cylinder on both sides of the piston with each other and with the suction chamber when the suction valve is unseated, said suction chamber being connected with the suction passage ot the engine, means for connecting the piston with the brake mechanism of the vehicle, yielding means for retracting the braleniechanisin and piston, means for arresting the valve actuating part in position to hold unseated the suction valve controlling said auxiliary passage when the piston is in retracted. position, and means for connecting the operator operated part with said bralre .inechanism, to enable the operator to apply his physical 'force thereto, in addition to that o the actuator.

or in case of failure ot power.

l?. In an automotive vehicle provided with an internal combustion engine, having a suction passage and bralte mechanism for the vehicle, the combination with power actuator comprising among its members a cylinder closed at both ends., a double acting piston in said cylinder, reversing valve mechanism located in the piston and includinga suction chamber, passages connecting it with the cylinder' on both sides of the piston, air inlet passages for the cylinder, and suction and air inlet valves controlling said passages, yielding means normally 'tending to seat said valves, a valve actuating part movable. with and "with respect tc lie piston, an operator operated part connected with the valve actuating part, said valve mechanism being constructed so that a, vement ot the valve actuating part in either direction with. respect to the piston will actuation of the piston in the saine direction, said piston being provided ivith c" nuiriliary passage extending therethrou ind controlled by one ot said suction. vaives, nd ,dapted t connect the portions oi the sides et the piston with the suction chamber when the suction valve is unseated, said suction chamber being connected with the suction passage of the engine, means for connecting the piston with the brake mechanism oi the vehicle, yielding means for retracting the brake mechanism and piston, means for arresting the valve actuating part in position to hold unseated the suction valve controlling said auxiliary passage ivhen the piston is in retracted position, and means for limiting the relative Inovement between the valve actuating part and the piston, to enable the operator to apply his physical force to the brake mechanism in addition to that ot the actuator, or in (iase ot failure of power.

18. ln an automotive vehicle provided with an internal combustion engine, having a suction passage and brake mechanism for the vehicle, the combination with a power actuator comprising among its members a cylinder closed at both ends, a double acting piffton in said cylinder, reversing valve mechanism located in the piston-and including a suction chamber, passages connecting it with the cylinder on both sides ot the piston, air inlet passages for the cylinder, and suction and air inlet valves controlling said passages, yieldingj means normally tending to seat said valves, a valve actuating part movable With and with respect to the piston, an operator operated part connected With the valve actuating part, said valve mechanism being constructed so that a movement ot the valve actuating part in either direction with respect to the piston will effect an actuation ot the piston in the saine direction, said piston being provided with an auxiliary passage ei:- tending therethrough and controlled by one ot said suction valves, and adapted to connect the portions of the cylinder on both sides ot' the piston with each other and with the suction chamber `when the suction valve is unseated, said suction chamber being connected with the suction passage ot the engine, means for connecting i the piston With the bralre mechanism ot the vehicle, yielding means for retracting the brake mechanism and piston, said operator operated part ybeing connected with the piston by means providing lost motion, to enable the operator to add his physical 'torce to the brale mechanism in addition to that of the actuator, or in case of failure of poWer 19. In a power actuator, the combination of a cylinder closed both ends, a piston in said cylinder, and yielding retracting means therefor, means for establishing diterential pressures on opposite faces of said piston including controlling valves located in the piston, an operator operated part, operative connections theretrom to said controlling valves, said'piston being provided with a passage for connecting the portions ot the cylinder on opposite sides ot the piston controlled by one of saidvalves for e ualizin pressures between the portions o the cy inder on opposite sides of the p1s ton, when said valve is in open position, said operator o erated part being connected with the piston y means providing lost motion, to enable the operator to apply his physical force to the part to be operated by said piston in addition to the power of the actuator, or in case of failure of power.

20. In a power actuator, the combination of a cylinder closed at both ends, a piston in said cylinder, and yielding retractin means therefor, means for establishing di erential pressures on opposite faces of said piston including Vcontrolling valves located in the piston, an operator operated part, operative connections therefrom to said controlling valves, said pistons being provided with a passage for connecting the portions of tlze cylinder on opposite sides of the piston controlled by one of said'valves for equalizing pressures between the ortions of the cylinder on opposite sides o the iston,when said valve is -1n open position, an means for holding thev said valve in open sition when the piston is in retracted pos1tion,.to maintain the piston submerged in vacuum, said operator operated part being connected with the piston Eby means permitting lost motion, to enable the operator to a ply his physical force to the part operate by the piston in addition to the power of the actuator, or in case of failure of power.

21. In an actuator, a cylinder,'a piston movable therein, passages for conveying high and low pressure motive Huid to and from' said cylinder to actuate said piston, relatively movable valves for said passages, an operator operated part for controlling said valves and an auxiliary passage connecting both ends of said cylinder with said low pressure and controlled by one of said valves. i

22. In an actuator, a cylinder, a piston movable therein, inlet and outlet' passages lfor conveying motive iiuid to and from said cylinder to actuate said piston, relatively movable inlet and outlet valves for'said passages, an operator operated part for controlling said valves and an auxiliary passage connecting theportions ofthe cylinder on opposite sides of the piston with each otherl and with the outlet passage, and independently controlled by one of said outlet valves. f

23. In an actuator, a cylinder, a piston movable therein, inlet and outlet passages' for conveying motive fluid to and from said cylinder to actuate said piston, relatively movable inlet and outlet valves for said passages, an operator operated part for controlling said valves, an auxiliary passage connecting the outlet passages and both ends of the cylinder andy controlled by one of said outlet valves, and means acting to unseat saidout'let valve adapted to equalize pressures on both sides thereof and controlled by one of said valves.

25. In an actuator, a cylinder, a piston movable therein, passages for conveying motive fluid to and from said cylinder to actuate said piston, valves for said passages, an operator f operated part, for controlling said valves, an auxiliary passage through said piston adapted to equalize pressures on both sides thereof and controlled by oneA of said valves, and means acting to unseat the valve controlling the auxiliary passage when said piston is in its normal retracted position.

26. In combination, an automotive vehicle having a power plant capable of driving the same and producing a source lof low pressure, a part to be actuated, an actuator for said part including a cylinder and-a piston movable therein, passages for connecting said cylinder with said source of low pressure from the power plant, and a source of high pressure to actuate the piston, relatively movable valves for controlling said passages, an operator operated part for controlling said valves, and an auxiliary passage connecting both ends of said cylinder for equalizing pressures on opposite sides of the piston, said auxiliary passage being controlled by a low pressure valve independent of other valves.

27. The combination with an automative vehicle having a power plant capable of driving the same and producing a source of lowpressure, of a part to be actuated, an actuator :for said part including a cylinder and a piston movable therein, passages for connectlng said cylinder with said low pressure source, and a source of high pressure, relatively movable valves for controlling said passages, an operator o rated part for controlling said valves, an an auxiliary passage connecting both ends of the cylinder to equalize pressure on opposite sides of the piston, said auxiliary passage being controlled by one of said valves independent of other valves.

28. The combination with an automotive .valves for controllmg said passages, an operator operated part for controlling said valves, an auxiliary passage connecting both ends of the cylinder to equalize pressure on opposite sides of the piston,said auxiliary passage being controlled by one of said valves,

and means acting to unseat said valve inde-- pendent of other valves when the piston is in normal retracted position.

29. In combination, an automotive vehicle having a power plant capable of driving the same and producing a source of low pressure, a part to be actuated, and an actuator for said part including a cylinder and a piston movable therein, passages for connecting the cylinder with said source of low pressure and with a source of high pressure to actuate said piston operator actuated valves for controlling said passages, and an auxiliary passage 4extending through the piston for connectmg both ends of the cylinder with each other and with the source of low pressure, said auxiliary passage being controlled by one of said valves.

30. In combination, an automotive vehicle having a power plant capable of driving the same and producing a source of low pressure, a part to be actuated, and an actuator for said part including a cylinder and a piston movable therein, passages for connecting the cylinder with said source of low pressure and with a source of high pressure to actuate said piston operator actuated valves for controlling said passa es, an auxiliary passage eX- tending throng the piston for connecting both ends of the cylinder with each other and with the source of low pressure, said auxiliary passage being controlled by one of said controlling valves, and means acting to unseat said controlling valve when the piston is in normal retracted position to connect the portions of the cylinder on opposite sides of the piston with each other and with the source of ow pressure.

In testimony whereof we afx our signatures.

CALEB S. BRGG. VCTR "W