US778044A - Fluid-pressure brake. - Google Patents

Description

.No. 778,044. PATENTED DEC. 20, 1904. A. A. KENT.

.FLUID PRESSURE BR'A'KE. APPLICATION FILED JUNB 13.1902. f

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No. 778.044. PATENTED DEC. 20, 1-904.

A. A. KENT.

FLUID PRESSURE BRAKE.

APPLICATION FILED JUNE 13.1902.

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9 6 a4 5 a 8 /3 m Z K E H Z W 4 N n E T V 6 A m m m VI I a W 7 a z y 6 7 7 0 m waif/0F n F T F J v w W M n W H w ,0 6 A .0 2 a. r .1. m I E 5 p. I w ,4 F4 Q W 9; o m w w 4 W 8 4 2 E 0 I4 I. m Q 1, [lo I I. W 6 o 5 3 0 5 k m u No. 778,044. PATBNTED DEC. 20, 1904.

" A-. A. KENT.

FLUID PRESSURE BRAKE.

APPLICATION FILED JUNE 13,1902. 7 N0 MODEL s SHEEIS-SHEET a.

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UNITED STATES PATENT OFFICE.

Patented December 1904 'ARTEMAS A. KENT, OF DENVER, COLORADO, ASSIGN OR OF ONE-HALF TO HENRY E. MILNER, OF DENVER, COLORADO.

FLUID-PRESSURE BRAKE.

SPECIFICATION forming part of Letters Patent No. 778,044, dated December 20, 1904.

I Application filed June 13, 1902. Serial No. 111,490.

To. all whom, it may concern.-

Be it known that I, ARTEMAs A. KENT, a citizen of the United States, and a resident of Denver, in the county of Arapahoe and State of Colorado, have invented a new and Improved Fluid-Pressure Brake, of which the following is a full, clear, and exact description.

My invention relates to improvements in fluid-pressu re brakes for railway-cars; and the primary object that I have in view is to dis- I -tribute the fluid-pressure to the series of cars I of a train proportionately to the varying weights of the loads in said cars. Thus in the case of a car bearing a heavy load an increase in the pressure of the braking fluid in the brake mechanism is obtainable, while a car with a lighter load does not require for the operation of its brake mechanism such high pressure of the braking fluid.

A further object of the invention is to antomatically regulate the supply of the braking force to the brake mechanism of each car in proportion to an increase or decrease in the weight of the load.

A further object of the invention is to provide an improved form of Valve mechanism in which the valve members are made to counterbalance one another, and with this valve mechanismis associated fluid-pressure devices having communication with the working chamber for the braking fluid and cooperating with the tension device in order to counterbalance the weightof the empty car-body.

Further objects of the invention are to provide a novel form of load-actuated means which is automatically brought into service by settling of the car-body on an increase in the load, to provide an automatic lock for certain parts of the load-actuated means to prevent retrograde movement thereof, and to provide an exhaust-valve from the regulating valvechamber to the train-pipe and adapted to automatically close under an increase in the brake-pressure fluid.

With these ends in view the invention consists in the novel combinations of mechanisms and in the construction and arrangement of the various parts for service, as will be herei inafter fully described. The actual scope of the invention will be defined by the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification,

in which similar characters of reference indicate corresponding parts in all the figures.

Figure 1 1s a side elevation of a portion of an ordinary railway-car and its running-gear,

illustrating the application of my improvements to a common style of fiuidpressure brake mechanism. Fig. 2 is an. under plan view of certain parts of the mechanism shown by Fig. 1. Fig. 3 is a vertical sectional elevation through one form of the balanced valve mechanism, one style of tension device therefor, and certain parts of the automatic load: actuated mechanism which controls the valve devices. Fig. 4 is a detail transverse section through the valve-cylinder on the line 4 4 of Fig. 3. Fig. 5 is a sectional plan view through the valve mechanism on the line 5 5 of Fig. 3. Fig. 6 is an enlarged view illustrating the automatic load mechanism and the locking devices for the slidable members thereof. Fig. 7 is a detail sectional plan view in the plane of the dotted line 77 of Fig. 6. Fig. 8 is a sectional elevation illustrating another style of fluid-pressure mechanism and a counterbalancing spring-tension device adapted for service in connection with the automatic pressure-regulating valve; and Fig. 9 is a detail view, inside elevation, illustrating another type of load-actuated devices.

A designates a part of an ordinary car-body, which is mounted in the usual Way upon the wheeled trucks B, and, as usual, this car is shown as equipped with a direct-fluid-pressure brake mechanism,having the usual brakecylinder O and the train-pipe D. As these parts are common and well understood by those skilled in the art, I have not considered -it necessary to fully illustrate and describe them in this specification, and they are only referred to herein for the purpose of enabling others to understand the construction and mode of operation of my improved pressurecontrolling mechanism.

While the invention is shown as applied to a car provided with a direct-pressure brake system, it is to be understood that the brake system itself forms no part of the invention, and the invention may, if desired, be applied to a car equippedvwith an automatic or indirect pressure system, and I do not, therefore, limit myself to the use of the invention with brake mechanism of either of the two types mentioned exclusively.

One of the prime features of my invention is a valve mechanism which is interposed in the line of communication between the trainpipe and the brake-cylinder, and in the accompanying drawings this valve mechanism is shown as consisting of a suitable shell or cylinder 5, the latter being mounted or supported in any suitable or preferred way on the under side of the car-body, preferably at or about the middle thereof and adjacent to the brake-cylinder, although the adjacent disposition of the valve mechanism to the brakecylinder is an immaterial feature of the system. This valve shell or cylinder is provided with a diaphragm 6, which is fitted closely within said cylinder, so as to assume practically a fixed position therein, and in this diaphragm is formed a down wardly-facing opening 7 and anupwardlyfacing opening 8, the two openings thus facing in opposite directions and located near opposite ends of the valve shell or cylinder. (See Fig. The diaphragm serves to divide the valve shell or cylinder into a supply-chamber 5 and a working-pressure chamber 5, and communication between the two chambers is controlled by means of the valve members 9 10, the same being arranged to work in opposite directions and to seat themselves in the openings 7 8, respectively. These two valves are connected operatively together for simultaneous movement through the medium of a lever 11, which is centrally fulcrumed within the valve-chamber, as at 11 and preferably on the diaphragm 6, and the end portions of this lever are pivotally connected with suitable stems or projections of the valves 9 10. The supply-chamber 5 of the valve-cylinder is in direct communication with the train-pipe D through the medium of a branch pipe 12, one end of which is attached to the valvecyl inder, while its other end is coupled to said train-pipe. The working-pressure cylinder 5 of the valve-cylinder is connected with the brake-cylinder C by the employment of another branch pipe, 13, having one end attached to the valve-cylinder and communicating at its opposite end with a suitable part of the brake mechanism, and by this arrangement of parts the valve mechanism is interposed directly in the path of communication between the train-pipe and the brake mechanism.

From this description of the valves it will be seen that one valve is arranged to move in the direction exerted by the fluid-pressure, and the other valve moves in an opposite direction to that in which the fluid-pressure acts thereon, and these valves are of equal area, so that they are balanced, whereby the valve mechanism is adapted to operate irrespective of any influence exerted by the working brakepressure.

In order to adjust the apparatus to the weight of an empty car-body, I employ an appropriate form of tension mechanism the energy of which is equal to the force required for the operation of the brake mechanism. This tension device includes a fluid-pressure mechanism and means for the application of mechanical force, and in the type of tension mechanism shown by Figs. 2 and 3 it contemplates the employment of an endwise-movable rod or bar 14, the same having operative connection with the valve-actuating device and adapted to receive the pressure of the fluid-pressure devices and of a tension-spring 15. This rod passes through a cylinder 16, which is shown by Fig. 3 as having one end supported on a part of the valve-cylinder 5, and the opposite heads of said cylinder 16 are provided with stuffing-boxes, as at 17, for the passage of said rod 14. A piston-head 18 is fixed to a part of the rod 14C where it passes through the chamber of the cylinder 16, and this piston is exposed to the pressure of the braking fluid, because the cylinder 16 is connected by a by-pass 19 with the working-pressure chamber 5 of the valve-cylinder. The by-pass 19 has one end coupled to the valve-cylinder, so as to communicate with the chamber 5 therein, while the other end of said by-pass is attached to the cylinder 16 at a point near the outer end thereof, whereby the piston-head 18 is The outer extremity of the piston-rod 14 is to be threaded, as at M jor the reception of an adjustable nut 20, and against this nut bears one end of a coiled tension-spring 2.1, the latter loosely encircling said piston-rod 14 at a point beyond the pressure mechanism comprised in the cylinder 16 and the pistonhead 18. The other end of the spring 21 is seated against a'loose collar or disk 22, which is fitted to move freely on the piston-rod 14:, and this loose collar or disk is in opposing relation to a similar collar 23, the latter being seated against one end of the cylinder 16.

Between the pair of collars or disks 22 23 are the weight of the load of the car. The spring 21 is thus arranged to exert its tension against the nut 20, which is fixedly attached to the piston-rod, and this spring thus acts on the piston-rod in opposition to the pressure exerted by the braking fluid on the piston 18, and when the pressure thus applied to the piston becomes greater than the tension force of the spring or its equivalent the rod 14 is moved in the direction of-the valve-cylinder, and by its connection with the lever 11 the Valves 9 and 10 are closed, and whenever the opposing force on the rod '14 exceeds the fluidpressure upon the piston or the pressure is released the rod 14 is moved from the valvechamber and the valves 9 10 are opened and the piston returned to a suitable position of action.

When the apparatus is adjusted or applied to a car, the nut should be rotated on the threaded part of the piston-rod in order to properly adjust the mechanism to compensate for the weight of the car-body when empty, and after this result shall have been attained no further manual adjustment of the valve mechanism or ofthe devices which cooperate therewith is required, because the load-actuated mechanism, to behereinafter described, will automatically adjust the valve mechanism in order to open the valves proportionately to an increase in the weight of the load that may be imposed upon the car-body.

I will now proceed to describe the automatic load-actuated mechanism which is operatively connected with the car-body and has certain parts thereof disposed in cooperative relation to the disks or collars 22 23 for the purpose of controlling the valve mechanism. The action of the load-controlled mechanism depends upon the vertical movement or displacement of the car-body under the imposition of the load thereof, and, as is well known by those skilled in the art, an increase in the weight of the load causes the springs which sustain the weight of the car-body to yield or give in a manner to allow the carbody to settle in a downward direction.

The slidable members 24 25, heretofore described, are wedge-shaped and disposed in opposite or reversed positions, as indicated more clearly by Fig. 3, and the inner ends of these members are disposed in overlapping relation and between the said loose collars 22 23. These inner overlapping wedge-shaped portions of the slidable members are forked or divided longitudinally in order to provide the slots or openings indicated at 26, and through these slots passes the extended por'- tion of the piston-rod 14, thus allowing the members to travel freely in endwise directions with relation to the piston-rod, and the latter is adapted to serve as a guide in retaining the bifurcated members in their proper operative relation. These members 24 25 extend in the direction of the length of the car and in opposite directions from the piston-rod, and the outer ends 'of said members journaled or mounted in said forks, so as to be movable with the slidable members. The

friction-rollers at opposite ends of the slidable members are disposed to ride against the levers 3O 31, and in the construction shown by Figs. 6 and 7 these levers are shown as being supported on a part of the car which is not influenced by the settling of the car-body A-as, for example, said levers may be fulcrumed on the trucks or a bar 32, supported by said trucks. The levers are made in the form substantially of bell-cranks, each having one arm thereof fulcrumed, as at 33, on the truck or a truck-supported bar 32, while its longer arm is disposed in an upward direction for engagement with the friction-rollers 29, and its remaining arm is operatively connected with the car body A through the medium of'a link 34, the latter being pivoted to the car-body and to said arm of the bell crank lever. In this form of construction I may find it desirable to employ means for automatically moving the slidablemembers 24 25 in opposite directions and to retracted positions, and one style of means for actuating said movable members is shown by Fig. 6, wherein a spring is employed, said spring engaging with an upstanding lug 36 on the slidable bar and with a suitable fixed projection 37 on the car-body. It will be seen that the springs normally impel the slidable members in directions away from each other, and the rollers or shoes 29 of these members are thus maintained in contact with the levers 81. When the load is imposed upon the carbody, the latter descends or settles for distances varying with the weight of the load, and this downward displacement of the carbody causes the links 34 to press the levers 3O 31 in directions which impel the slidable members 24 25 inwardly. The wedge-shaped portions of these members are thus forced between the loose disks or collars 22 23 in order to increase the area of overlap between the members, and the collar 22 is thus forced toward the nut 20, so as to increase the tension of the spring 21, whereby the energy of the spring overcomes the pressure of the braking fluid in the piston-cylinder 16, and the pistonrod 14 is thereby moved in a direction away from the valve-chamber, and by the adaptation and connection with the several parts the valves 9 10 are opened to admit an increase of pressure to pass into the working-force chamber 5 that will equally proportion the braking force required by the additional loadweight and the corresponding displacement of car-body, thus permitting the right proportion of the braking fluid to pass from the train-pipe D, through pipe 12, chamber 5,

parts 6 7, the Working chamber 5 and the pipe 13, into the cylinder of the braking mechanism. I

When the load is decreased or removed, the car-springs operate to lift the body A, which of course reduces the strain on the links and the levers 3O 31, so as to allow the springs 35 to again become active in moving the slidable members to their retracted positions, whereupon the tension of the spring 21 is reduced and the piston-rod 14 is allowed to descend, and the several working parts automatically adjust themselves in a suitable manner, as heretofore described, to afford and maintain a suitable proportionate braking force to whatever load-weight (if any) remains.

Under some circumstances I may find it desirable to employ means for locking the slidable members 24 25 against retrogrademovement, and in Figs. 6 and 7 of the drawings I have shown automatic grippers which remain idle during the forward or inward movement of said slidable members to their active positions, the said grippers engaging with certain stationary parts in order to restrain the slidable members from movement accidentally in opposite directions. Each slidable member is provided with a hanger 38, which is fitted to the arm 27 and is held in place by any-suitable meansas, for example, the set-screw 39. The hanger depends a suitable distance below the arm of the member in order to support a gripper 40, the same being pivoted in the hanger. as at 41, and provided with an extended arm forming a shoe 42, the latter adapted to bear or ride upon a locking-bar or rod 43, which is attached to apart of the car-truck or to a truck-supported bar 32. This gripper is normally acted upon by a suitable retractor, which is shown in the form of a spring 44, that is seated against the arm 27 and against said gripper in order to hold the shoe 42 firmly in engagement with the looking bar or rod 43. In order to release the gripper when it is desired to move the member in a backward direction, I provide a releasing-rod 45, the same having one end connected loosely, as at 46, to a lever 30 or 31, while its other end is provided with an upstanding finger 47, which is arranged to fit in a slot or recess 48, which is provided in the lower part of the gripper at a point to one side of the shoe 42 thereof. This finger of the releasing-rod is arranged to play idly in the slot of the gripper when the slidable member is forced to its active position by the displacement of the car-body and the movement of the lever which is linked thereto, and said finger does not interfere in any way with the operation of the gripper, which serves to hold the slidable member from accidental retrograde movement; but when the load is removed and the car body is lifted by the springs the lever 30 or 31 is moved so as to impart slidable adjustment to the releasingrod 45, and the finger 47 thus becomes active in lifting the shoe 42 from engagement with the bar or rod 43, thus permitting the slidable member to be returned to its normal position. In Fig. 9 of the drawings I have represented another form of load-actuated mechanism which is positively operated by the displacement of the car-body. It will be understood that the slidable member 25 is slotted and provided with a wedge-shaped active face so as to cooperate with a similar slidable member corresponding to the part 24. This member 25 is shown as having the roller or shoe 29, and it is supported in a suitable hanger 48. The shoe is adapted to ride against a lever 49, which is the equivalent for the lever 30 or 31, and this lever 49 is mounted on a suitable support 50, which is not influenced by the displacement of the car-body. The short arm of the lever 49 is equipped with a roller or shoe 51, that is adapted to ride against the inclined active edge 52 of a cam 53, the latter being made fast with a sill of the car-body in a manner which will be readily understood.

54 designates a valve-shell having communication with the branch pipe 12 at a point between its union with the valve-cylinder 5 and the train-pipe D, and this valve-shell is also connected with the valve-cylinder at a point to communicate with the working-pressure chamber 5". Within the valve-shell 54 is arranged a movable valve-chamber 55, which is adapted to close against a seat 56 whenever the prime or supply force exceeds the working force in the chamber 5 of the valve-cylinder. The pressure of the braking fluid thus automatically seats the exhaust-valve 55 so as to force the braking fluid to pass through the pipe 12 into the chamber 5 and through the openings 9 10 into the chamber 5", from whence the braking fluid passes through the pipe 13 into the brake mechanism; but when the brake-pressure is reduced this valve 55 is adapted to open in order to relieve the pressure in the valve-cylinder and in the cylinder 16, which is connected with the valve-cylinder by the by-pass l9, whereupon the valves 9 10 are adapted to be opened by the action of the spring 21.

In Fig. 8 of the drawings I have represented another embodiment of the tension mechanism, in which the cylinder 16 and the piston 18 are omitted, and in lieu of the single spring I employ a series of springs. A suitable framework 57 is provided adjacent to the valve-cylinder 5, and this framework is provided with suitable guides, as 58, to accommodate the slidable rod 14. This rod has the threaded section 14, which receives the adjusting-nut 20, against which bears the coiled spring 21, which in this instance has its opposite end seated against one of the guides 58. Another nut, 59, is mounted adjustably on the slidable rod 14 at a point adjacent to the guide 58, just referred to, and a spring the character hereinbefore disclosed.

is fitted loosely around this slidable rod,

so as to have one end engaged with the ad justable element 59 and with the loose collar or disk 23*, which is shown as resting upon the valvecylinder.. It will be seen that the energy of both the springs is applied to the rod 14 in order to oppose the pressure of the fluid within the expansible chambers 62 63 M, as their expansion, caused by the pressure of the fluid, controls the action of the valves 9 10. Between the collars 22 and 23 are interposed the overlapping wedge-shaped ends of the slidable members 24* 25, which form parts of the load-actuated mechanisni lclif e fluid-pressure devices of this tension mechanism are embodied in the form of expansible chambers 62 63 64:, which act against bearing-collars 65, that are made fast with the slidable rod 14. These expansible chambers may be constructed of any suitable material which will permitthem to be enlarged or expanded laterally by the pressure of the brak ing fluid, which is supplied from one of the chambers of the valve-shell through the medium of the connecting-pipe 66, one end of said pipe being attached to the valve-shell for communication with one of the chambers thereof, while the other end of the pipe is equipped with the series of branches 67, adapted to have communication individually with the series of expansible chambers.

In order that the uppermost expansible chamber may operate eificiently, I prefer to employ a bearing-surface 68 on the relatively stationary frame 57, and one of the bearingcollars is interposed between the two adj acent expansible chambers, thus making provlsion for each side of each expansible chamber to exert proper action on the slidable rod 14. The utility and operation of the mechanism just described is similar to the devices heretofore described in connection with Figs. 1, 2, and 3 of the drawings, and it will be sufficient to state that the combined expansion of the series of chambers exerts the necessary force upon the slidable rod 14 in order to close the balanced valves when the right proportion of fluid-pressure has been admitted to the valve-cylinder, according to the weght of the car and its load. In the arrangement just described employing the springs 21 60 a certain pressure is required to overcome the tension of said springs, and to this pressure should be added sufficient resisting force in order to regulate the braking force suited to empty cars. The tension of the spring 21 may be increased by adjusting the nut 20 toward the cross-bar or seat 58, and the regulation of the braking force to suit the weight of the car can be secured by the adjustment of the element 59 in order to increase the tension of the spring 60. The combined action of the springs 21 60 is opposed to the pressure of the braking force as applied to the expansible chambers 62, &c., for the purpose of regulating the action of the valves 9 10 in a suitable manner to insure an equalized distribution of the fluid-pressure to a series of cars of a train in proportion to the several weights of cars and loads thereon, and the energy of the combined springs is overcome in a positive manner by the inward movement of the slidable members which form parts of the load-actuated mechanism.

It is to be understood that my invention is in the nature of an attachment that may be used in connection with anyone of a number of different fluid-pressure brake systems of which I have knowledge, and this is susceptible of accomplishment without such changes in the system as will affect the operation peculiar to such systems of applying and releasing the brakes.

In devising and perfecting my invention I have sought to provide means which are effective for the purposes that I have in view and which are not dependent upon a triple valve or any other certain device or appliance of existing brake systems. The construction as shown and described admits of any desired location of the parts between a source of supply and the brake-cylinder. The improvements are entirely automatic in operation, and when they are properly attached and adjusted the operation of the brakes and the management of the train will in no wise be affected by the use of the said improvements.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a fluid-pressure brake, the combination of a balanced valve in the line of communication between a brake mechanism and a source of supply, a tension-rod connected with the movable members of said valve, a mechanical retractor operatively connected with said rod, fluid-pressure devices cooperating with the rod and having a by-pass connection with a chamber of said valve, and load-actuated devices connected with said valve.

2. In a fluid-pressure brake, the combination of a balanced valve in the line of communication between a brake mechanism and a source of supply, said valve having a divided chamber and connected valve members movable simultaneously in opposite directions, a tension-rod connected with said valve members, a retractor opposingthe movement of the rod in one direction, a fluid-pressure device also opposing the movement of the rod, a-by-pass connected with said fluid-pressure device and with one chamber of said valve, and load-actuated devices to shift said valve.

3. In a fluid-pressure brake, the combination with a brake mechanism and a source of supply therefor, of a balanced valve having a divided chamber in communication with said brake mechanism and the source of supply, and oppositely-movable valve members connected for simultaneous movement, a load-actuated mechanism having operative connection with said valve to automatically actuate the latter,

and a tension device also connected with said valve to hold the latter closed in opposition to the braking force in the divided chamber, said tension device having regulatable means for varying the pressure exerted on the valve.

4. In a fluid-pressure brake, the combination with a brake mechanism and a source of supply therefor, of a balanced controllingvalve having a divided chamber interposed between the source of supply and the brake mechanism, and oppositely-movable members connected for simultaneous movement, a loadactuated mechanism operatively connected with said valve, and atension device connected with said valve mechanism and including a spring-actuated rod and fluid-pressure devices both arranged to close the valve in opposition to the braking pressure, said fluid -pressure devices being in communication with one compartment of the divided valve-chamber.

5. In a fluid-pressure brake, the combination with a brake mechanism and a source of supply therefor, of a balanced double valve interposed in the line of communication between said brake mechanism and said source communication with one compartment of the double valve and cooperating with said tension-rod to close the valve in opposition to the braking pressure, and load-actuated mechanism connected operatively with said tensionrod and arranged to act thereon to overcomethe resistance of the spring and the fluid-pressure devices.

6. In a fluid pressure brake, the combination with a brake mechanism and a source of supply therefor, of a balanced valve interposed in the line of communication between said brake mechanism and the source of supply, a spring-actuated rod pivotally connected with said balanced valve, and slidable members for positively shifting said rod and thereby actuating said valve.

7 In a fluid-pressure brake, a pressure-controlling valve having a divided chamber, the compartments of which communicate with a brake-cylinder and a source of supply respectively, a valve-lever, and oppositely-movable valve elements connected with said lever to be actuated simultaneously thereby, combined with a tension device operating on the valve in opposition to the braking pressure, and loadactuated means to open or close the valve on a variation in the car-load.

8. In a fluid-pressure brake, the combination of a pressure-controlling valve for a brake mechanism, a slidable rod connected to said valve and normally held under tension, fluidpressure devices cooperating with said rod in holding the valve closed in opposition to the braking pressure and communicating with said valve mechanism, and load-actuated slides operatively related to said rod to positively shift the latter and open the valve. v

9. In a fluid-pressure brake, the combination of a pressure-regulating valve for a brake mechanism, a slidable rod to the movable element of said valve, a retract-or operatively connected with said rod to close the valve in opposition to the braking pressure, fluid-pre sure devices communicating with a part of said valve mechanism and acting on said rod to cooperate with said retractor, fixed and slidable collars surrounding the rod, and loadactuated slides arranged between said collars and operable to positively increase the energy of the retractor.

10. In a fluid-pressure brake mechanism, the combination of a pressure-regulating valve in communication with a brake mechanism, a slidable rod controlling said valve mechanism, a spring, an adjustable element carried by the rod and furnishing a seat for the spring to regulate the tension thereof, and load-actuated wedge-shaped slides arranged to positively increase the tension of the spring in proportion to an increase of load on a car-body.

11. In a fluid-pressure brake mechanism, the combination of a pressure controlling valve, a tension device acting on said valve mechanism in opposition to the braking pressure, load-actuated wedge-shaped slides operatively fitted to a part of the tension device, and pivoted members engaging with said wedge-shaped slides and controllable by the displacement of a car-body.

12. The combination of a pressure-controlling valve mechanism having communication with a brake mechanism, a tension device controlling said brake mechanism, and a load-actuated mechanism for increasing the energy of the tension device and comprising slidable wedge-shaped members disposed in overlapping relation, and pivoted members actuated by displacement of a car-body and arranged to simultaneouslyimpart inward movement to said slidable members.

13. In a fluid-pressure brake mechanism, the combination of a pressure-controlling valve, a tension device acting on the valve in opposition to the braking pressure, load-actuated slides fitted to said tension device, and locking devices individually fitted to the loadactuated slides to restrain them from accidental retrograde movement.

1a. In a fluid-pressure brake, the combination of a pressure-controlling valve, a tension device acting on said valve in opposition to the braking pressure, load-actuated slides arranged to positively increase the energy of said tension device, locking devices to restrain said slides against retrograde movement, and means for automatically releasing said locking devices on the return of the load-actuated devices to normal position.

15. In a fluid-pressure brake, the combination of a pressure-regulating valve, a tension device for said valve, load-actuated wedgeshaped slides arranged to overlap each other and positively increase the energy-of the tension device on the inward movement of the slides, locking devices in separate cooperative relation to the slidable members, and means actuated by the pivoted members to release said locking devices.

16. Ina fluid-pressure brake mechanism, the combination with a valve mechanism and a tension device, of slidable members fitted to said tension device, car-controlled devices arranged to positively actuate said slidable members, stationary locking-rods adjacent to the slidable members, grippers movable with the slidable members and arranged to engage with said locking-rods, and means for releasing the grippers'from the locking-rods.

17, In a fluid-pressure brake, the combination with a train-pipe and a brakemechanism, of a pressure-controlling valve having a divided chamber communicating with said train-pipe and the brake mechanism, load-actuated means to open said valve, and an eX- haust-valve between one chamber of the valve mechanism and a branch leading from the train-pipe.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ARTEMAS A. KENT. Witnesses:

.W. S. DUGGER, Mrs. Y. Y. STEEvENsoN.

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