US567476A

US567476A - Air-brake

Info

Publication number: US567476A
Authority: US
Publication date: 1896-09-08
Anticipated expiration: 1913-09-08

Description

2 Sheets-Sheet (No Modei.)

- H. L. HOWB.

AIR BRAKBf Patented Sept. 8, 1896.

% e? Y `I. 59 H' y 10.657,476. Patented sept. 8, 1896.

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I INVNTOR wlTNEssEs: i( XM @0. QM

ATTORNEY?.

onms Pzrzws w. P WASHINGTON u c UNITED STATES `PATENT @Erica HENRY L. Howe, or CANANDAIGUA, NEW YORK.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 567,4"76, dated September 8, 1896.

Application filed July 12, 1895. Serial No. 555,728. (No model.)

To @ZZ whom, t 11i/ay 'coll/cern.' Y

Be it known that I, HENRY-FL. JIIOWE, a citizen of the United States of America, residing at Canandaigua, Ontario county, State of New York, have invented certain new and useful Improvements in Air-Brakes, of which the following' is a specification.

My invention relates to that class of fluidpressure brakes especially adapted for streetcars, but is not necessarily coniined, in its practical applications, to use with such vehicles.

The invention has for its objects to economize power, as by utilizing the power stored up in the moving car; to automaticallymaintain a predetermined pressure in the air-reservoir; to effect the application of the brakes and the simultaneous restoration of the normal pressure in the reservoir, thus making the air-supply practically inexhaustible; to provide in the same apparatus for the restoring of air-pressure independentlyof the operation of the brakes; to protect the operative parts of the apparatus from dust; and finally, in attaining` these desirable ends,.to lessen the number of parts, simplify the construction of the apparatus, and enhance its economy of manufacture and durability. I secure these objects by enabling the air pump or compressor, which is operated-from one of.

the axles of the vehicle, to be entirely disconnected from such axle and cease all movement except when it is desired to apply the brake, or when the' air-pressure has fallen below the normal and requires to be restored, or when an excess of pressure is needed, and, by preference, during the act of applying the brakes, by making the act of such connection or disconnection dependent upon the degree of air-pressure in the reservoir, the latter being in direct communication with the connecting or disconnecting mechanism; by providing means by which the act of applying the brakes will effect or permit the operation of the pump; by providing a means, under the direct control of the brakeman, for causing the air-pump to be at will connected with pump; and by various new and improved -employed in every practical application of the invention, as some of such objects may `be usefully realized without the others, but I prefer, and shall hereinafterdescribe, a complete air-brake system embodying in one con'- .struction all of the features Which/I have enumerated.

In order to make my invention more clearly understood, I have shown in the accompanying drawings means for carrying themy into practical effect, without limiting my improvements in their useful applications to the particular construction which, for the sake of illustration, I have delineated.

In said drawings, Figure l is a diagrammatic View showing certain of the parts in horizontal section of an air-brake apparatus suitable for a street-car and embodying my invention. Fig. 2 is asectional view on line II II, Fig. l, of the .stop-cylinder and clutch, constituting the means for connecting and disconnecting the air-pump and vehicle-axle. Fig. 3 is a section on line III III, Fig.v2, of vsaid clutch. Fig. 4 is a sectional view of the air-controlling valves and operating mechanism. Fig. 5 is an end view of a portion of ysuch mechanism. gitudinal section of the air pump V or compressor on line VI VI, Fig. 7. Fig. 7 isa vertical section of the same on line VII VII, Fig. 6. 1

Referring to the drawings, l indicates a portion of a supporting-axle of the vehicle to which the brake system is applied, carried by the usual-wheels, (not shown,) adapted to run on the ground or upon a track:

2 is the driving-shaft of the air pump-or. compressor 3, the latter being located at any convenient point, as beneath the floor of the vehicle.

Any suitable connecting mechanismV may be employed to communicate the rotation of the axle to the shaft 2, such, for instance, as vsprocket-

wheels

4 and 5, ixed,respectively, on the axle and shaft and connected by a chain 6.

VV-hile any desired form of pump may be `employed in carrying out my invention, I prefer the improved construction shovvn.{ It

Fig, 6 is a horizontal lon- ICO comprises two cylinders 7, cast together and provided with pistons 8,united by connectingrods 9 with the oppositely-arranged or balanced cranks 10 of the shaft 2. These rods are pivoted to the pistons by pins or bolts 11, having bearings in lugs 12 cast in the pistons and passing into said bearings and through the eyes 13 of the rods through apertures 14 in the outer sides of the pistons. The connections of the rods with the cranks 10 are of any usual or approved character.

15 is a casing bolted to the open ends of the cylinders, entirely inclosing the cranks and rods and keeping dust from said parts and from the cylinders, their valves and pistons. One half or portion 16 of the casing is fixed, carries bearings 17 for the shaft 2, and is adapted to be attached to the vehicle, thus forming the support for the pump-shaft. The other portion 18 of the crank-casing is removable to give access to the parts. The other ends of the cylinders are coveredbya valveplate 19 and head 20, which are bolted in place. Opposite or in each cylinder 7 the plate is formed with air ingress and egress ports 2l and 22 and corresponding inn-er and outer valve-seats 23 24. Suction an d delivery valves 25 and 2G rest on said seats, being mounted on pins 27 28, iiXed in bridges 29, which are cast with the plate and extend across the ports. The pin 27 has an interior head, between which and the valve is coniined a spring-washer 30, acting to normally hold the valve on its seat, but yielding inward to release the valve and admit air when the piston moves away from the valves. On the outer end of the pin isa lock-nut 31, by which the pin, when once adjusted in the bridge 29 so as to bring the proper spring-pressure to bear on the valve, may be secured. The valve 26 and its washer 30 are mounted on the outer end of the pin 28, and are adjusted by a nut 32,.secured byla lock-nut 33. In the head 2O are formed air-

passages

34 and 35, the former leading from the atmosphere to the suctionvalve of each cylinder and the latter leading from the delivery-valve of each cylinder to the air-reservoir. The former communication is effected by a pipe 36, which extends up within or above the vehicle or to any point free or comparatively free from dust, while communication of the passage 35 with the reservoir is had through a pipe 37.

As the pump-shaft 2 is rotated by the mechanism already referred to, the pistons 8 alternately draw in atmospheric air through the valves 25 and deliver it through the valves 26 to the air-reservoir, two cylinders full of air being compressed for each revolution of the shaft.

The above -described construction offers several advantages, the most important of which are lthat the cylinders,pistons, rods,and cranks are completely inclosed; the inclosin gcasing can be partly iilled with oil, which will lubricate all of the working parts, including the pistons Without further attention; the

single-acting pumps need no packing; the pressure on the pump-shaft being always in one direction on the journals there is no difiiculty with any slack that may occur; the valves being in the cylinder-head minimize the clearance and consequently give the pump more capacity; and the pump being self-contained is easily put in any position and is not liable to be put out of line.

The compressed-air reservoir is shown at 38, consisting of a strong casing, such as a cylinder of boiler-iron, capable of containing with safety a normal pressure of, say, thirty pounds, or other desired amount. Vhen this pressure is attained, the brakeman may cause the pump to cease operation, through devices hereinafter described, but in order that this pressure may not by inattention be exceeded, and to relieve the motive power of the vehicle of unnecessary work in operating the parts of the pump, (even if the latter be prevented in a well-known manner from further compressing air,) I provide means for automatically disconnecting the pump entirely from the vehicle-axle as soon as the normal pressure in the reservoir has been reached, said means being operated by the 'air from the reservoir.

The means whereby the reservoir-air may control the mechanical connection between the pump and axle can take a variety of forms without departing` from my invention, but I prefer that which I will now describe, comprising a huid-pressure device operated by reservoir-pressure and controlling the mechanical connections between the axle and pump.

39 is a cylinder or casing, which I will term a stop-cylinder, one side of which is in constant communication with the reservoir through a pipe 40, and which is provided with a piston 41, adapted to be acted upon and actuated by the pressure from the reservoir through the pipe 40. These parts constitute the fluid-pressure device above referred to. A spring 42 acts upon said piston in the opposite direction, and its strength is of such predetermined amount that it will overcome said pressure and hold the parts in the position shown in full lines in Fig. 2, (in which position the pump-shaft and axle are connected, as hereinafter described,) until thev normal pressure of thirty pounds in the reservoir has been reached. Then the spring 42 will be overcome and the piston 41 moved from its normal position (shown in Fig. 2) to the opposite end of the cylinder. The mechanical connections between the pump or compressor and its motor comprise a clutch, by which term I intend any means for connecting the compressor with or disconnecting it from the motor. Said clutch is preferably constructed and operated as follows: 44 is a stem carried by the piston 41 in line with the pump-shaft 2, and adapted to move longitudinally a stem 45, mounted in said shaft. The inner end of this stem is connected with a cross pin or bar IOO IIO

` the shaft 2.

46, fitted and adapted to play in a slot 47 in Mounted loosely on the shaft is the Wheel 5, already referred to, having on the inner face of its hub projections or shoulders 48, with which engages the pin 46, Fig. 3, when in its Outer position. 49 is a spring in the end of the shaft 2 and adapted to press and hold outward, until overcome by the airpressure on the piston 41, the stem 45 With its pin 46. It Will noW be seen that when the reservoir 38 has been charged to its maximum and normal pressure the movement of the parts 41, 44, and 45 will carry the pin 46 in- Ward out of engagement With the projections 48 of the Wheel'5, thereby leaving the latter loose on the shaft 2 and free toV rotate under the operation of the chain 6 Without turning the shaft of the pump or operating the latter. The parts remain in this inoperative position until by the expansion of the reservoir-air for braking purposes, as hereinafter described,

Vthereservoir-pressure on one side of the piston 41 is reduced below the counter-pressure of the sprin'gj42 on the other side, whereupon the stem 45 Will be released and the spring.

49'Will carry the' pin 46 into engagement With the constantly-rotatin g projections 46. The pump Will thereby beset in operation and the reservoir pressure restorred to'normaLWhereupon the pin 46 Will be again disengaged and the pump Will be stopped.

- It is necessary for the Vquick andpositive disengagement of the pin 46 from shoulder 48 that the pressure Which actuates the piston 41 be momentarily retained at a point in excess of that necessary to overcome the counter-pressure of the springs. i The friction of the shoulders 48Aagainst the pin' 46 While driving the shaft 2 Will effect this until the'revolution of said shaft-shall bring .the cranks to the position of passing their centers, at Which timev the pump-piston atV the end of the compression stroke will bel returned by the expansion of the air sufliciently to throu the' crank-shaft ahead, and thus'momentarily release the pin46from'the shoulders 48, so that the excess or banked-up pressure acting on piston 41 will quickly carry

4,6 clear of shoulders 48. It is equally necessary that the positive and quick engagement of the pin46 With shoulders 48 should be made,'and'to assure this the shoulders 48 should be preferably'tWo (2) in number, thus admitting of a partial revolution ofthe Wheel before the engagement is permitted.

Whether the compressed air supply be maintained as above described or by any other equivalent or preferred means, l have provided an improved valve for controlling it and applying it for braking purposes, to Whichl Will nOW, refer in detail. Vis a valve, of which 50 is the casing, preferably of cast Vmetal,`containing the air-controlling valves proper. Said casing has a main chamber 51, with which may be caused to communicate a chamber 52connected bya pipe 53 with the reservoir, a chamber 54, connected by a pipe 55 With the brake-cylinder, and an exhaust-chamber 56, communicating by a duct 57 with the atmosphere. The communications of these three chambers With the chamber 51 are controlled, respectively, by spring-actuated

valves

58,59, and 60, opening in directions'away from the main chamber and having stems or

projections

61, 62, and 63 extending into the latter. The valves are guided in their movements by these stems and by outer stem 64, sliding in closing-plugs 65, screwed into the outer ends of the several chambers.

66 is the brake-cylinder, of the usual character, With Which communicates the pipe 55, as aforesaid, and having a piston 67, the rod 68of which is connected With and operates the brake-shoes, one of Which latter is indicated at 69 and its Wheel at 70.

When the 'valves 58 and 59 are both open, the compressed air from the reservoir Will be immediately admitted to thevbrake-cylinder, the brakes applied, and the vehicle stopped. Whenthe valve 58'is` reseated and valves 59 and opened, the air from the brake-cylinder Will be permitted to' exhaust' through` the aperture 57 and the spring 71 of the brakepiston Will release the brakes. These valve movements are conveniently effected by a cam 72, mounted in the chamber 51 upon a transverse rock-shaft 73, the latter being actuated at Will bythe brakeman through a handle 74, conveniently situated, (say at the front of the vehicle), a rod 75, and a crank-arm 76, fixed on thecam-shaft. The cam is formed With a linger or projection 77, situated between and adapted to force outward either of the valvestems 61 or 63, with a consequent opening of its`valve, and With projections 78 and 79, eitherof which is adapted to force outward the stem 62and open the valve 59, according to the direction in Which the handle 74 ismoved and the cam rocked. The projections 78 and 79 are so arranged relative to the finger 77 that the linger Will operate iirst to open its valve by a slight movement of the handle 7 4, (say to the notch 8O or 81 of the handle-controlling`segment,) While a farther4 movement of the' cam, (the handle being moved to the notch- 82 or 88,) will keep the rst valve open IOO IIO

and cause the projection 78 or 79 to open the While shifting it to the notch 83 Will release them. c

The movement of the handle to the notch 80 will open the reservoir to the chamber 51, and

to the notch 81 Will open the latter .chamber to the atmosphere, Without in either case` affecting the brakes.- But these movements effect other` useful purposes, as Will now be described.

with which communicates a pipe 85, leading to an opening 86 in the stop-cylinder 39. ,It

is obvious'that the communication ,maybe v 13o -84 is an opening into the main chamber 51,

directly from the brake-cylinder to the stop or controlling cylinder 30. This latter opening 8G is at the opposite side of the piston 41 from the pipe 40, the consequence of which is obvious. The parts being in the position the reverse of that shown in Fig. 2 with the pump out of operation, and it being desired to attain a reservoir air-pressure above the normal, the handle 74 is moved to the notch 80. This will open the valve 58, but not the valve 59, and will admit reservoir-pressure into the stop-cylinder on the same side of the piston as the spring. The two acting together immediately overcome the pressure in the pipe 40, cause the parts 46 48 of the clutch to engage, and enable the wheel 5 to operate the pump. This operation will now continue indefinitely, but may be stopped by moving the handle 74 to the notch 81, whereupon the valve 58 will close and the valve 60 be opened, placing the stop-cylinder 39 in communication with the atmosphere. The spring 42, unaided, will be immediately overcome by the reservoir pressure in pipe 40 and the parts of the clutch unlocked, disconnecting the pump from the axle. l

Exhaust-valve 60 opens with the pressure, and, as shown, the valve actsas a safety or relief for the pressure thrown in to brake-cylinder. The other valves are held seated by the pressure in addition to their respective springs. Vhen the communicationfrom the operating valve to the stop-cylinder is through the brake-cylinder, the pump will only start when there has been sufficient air drawn out of the reservoir and thrown into the brakecylinder.

lt will thus be observed that the operation of the pump is under the control of the brakeman irrespective of any operation of the brakes. At the same time the air-supply may be entirely kept up to the predetermined normal pressure by that operation of the pump which automatically occurs when the brakes are applied, as already explained, the pump being so proportioned and geared that it will restore to the reservoir the full pressure of thirty pounds in the distance traveled by the car while being stopped. The amount of air withdrawn from the reservoir to apply the brakes being thus pumped into the reservoir while the brakes are being applied, the air supply and pressure is practically inexhaustible, and the operation of the pump at this time assists in stopping the car. A safety-valve 87 is placed on the reservoir and arranged to carry such maximum pressure as may be advisable. The constant communication between the chamber 51 and the stop-cylinder immediately causes the piston 41 to be balanced, so far as air-'pressure is concerned, upon the opening of the valve 58. This will leave the spring 42 free and cause the pump to be started, whatever be the pressure in the reservoir. After applying the brakes the camfinger may be returned to its normal central position, allowing all valves to close and leaving the brakes on and the pump in operation. A return movement of the finger against the valve-stem 63 will exhaust the stop-cylinder and release and stop the pump, as already eX- plained, without releasing the brakes; but notwithstanding this independent capacity of operation of the pump and brakes, the application of the latter is always accompanied by the starting of the former.

The placing of the operation of the pump under the direct control of the motorman or driver not only simplifies the mechanism, but does away with the liability of automatic mechanism causing a failure of the brakes to operate when most needed.

The failure of the only automatic mechanism used in the above-described system will be an error on the safe side, and if the pump should run too long the only harm would be the waste of air through the safetgf-valve.

What is claimed is-n 1. In a fluid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device independently controlling communication between the reservoir and the brake-cylinder and between the reservoir and controllingcylinder, as set forth.

2. In a fluid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device independently controlling communication between the reservoir and controlling-cylinder, and between the reservoir, brake-cylinder and controlling-cylinder, as set forth.

3. In a fluid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device independently controlling communication between the reservoir and the brake-cylinder, between the reservoir and controlling-cylinder, and between the brake-cylinder and exhaust, as set forth.

4. In a duid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device independently controlling communication between the reservoir and the brake-cylinder, between the reservoir and controlling-cylinder, and between the controlling-cylinder and exhaust, as set forth.

5. In a huid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device independently controlling communication between the reservoir and the brake-cylinder, between the reservoir and the controlling-cyl- IOO inder, and between the brake-cylinder, controlling-cylinder and eXhaust, as set forth.

6. In a fluid-pressure brake, the combination of a pump, a reservoir a brake-cylinder having communication therewith, a controlling-cylinder determining the ope'ration of the pump, and having two connections with the reservoir and a suitable valve device controlling communication between the reservoir and brake-cylinder and also one of said connections with the controlling-cylinder, as set forth.

7. In a fluid-pressure brake, the combination of a pump, a reservoir a brake-cylinder havingcommunication therewith, a controlling-cylinder determining the operation of the pump, and a suitable valve device controlling communication between the reservoir and brake-cylinder, and independently controlling communication between the reservoir, controlling-cylinder and exhaust, as set forth.

8. In a fluid-pressure brake, the combination of an air pump or compressor, connections from the same to an actuating means such as a vehicle-axle, a reservoir supplied by said pump, means for regulating the application of the fluid-pressure to the brake, a fluid-pressure device having two independent communications with the reservoir and controlling the connection of the pump with its actuating means, a valve in one of said independent connections to cause a movement of said device independent of the application of the brake, and the other communication constantly open to the fluid-pressure device as set forth.

9. In a fluid-pressure brake, the combination of a brake-cylinder and pump, a reservoir in communication with the same, a iiuidpressure device controlling the action of thepump and having communication at one side with the reservoir, a passage from the other side of said device to the reservoir, and a valve device controlling said passage and communications whereby on the admission of huid-pressure to the brake-cylinder it is also admitted to the said other side of the pressure device and also independently controlling said passage, substantially as set forth.

l0. In a fluid-pressure brake, the combination with a pump and reservoir, of a stopcylinder and piston,communications between the reservoir and stop-cylinder on opposite sides of said piston, a valve controlling one of said communications independent of the application of the brake and the other communication constantly open to the stop-cylinder, as set forth.

ll. In a fluid-pressure brake, the combination with an air-compressor and means for actuating the same, of a reservoir supplied thereby, a brake apparatus or cylinder, a passage leading from the reservoir to the brakecylinder, avalve controlling the said passage, a fluid-pressure device connected with the communications with the reservoir and controlling said clutch, a valve in one of said vcommunications to cause a movement of said device independent of the application of the brake and the other communication constantly open to the fluid-pressure device, as set forth.

13. In a fluid-pressure brake apparatus a huid-controlling valve, comprising three independent valves and a cam arranged to engage either one of two of said valves, and either of said two valves and the other valve, substantially as set forth.

l-l. In a huid-pressure apparatus a fluidcontrolling valve, comprising three valves proper, and a cam having three lingers, one finger for actuating either one of two of said valves, the other two fingers for operating the other valve in opposite movements of the cam, substantially as set forth.

15. The combination with the reservoir brake-cylinder and exhaust, of a valve comprising a casing having three ports, a valve controlling each of the same and adapted by their operation to place said reservoir and brake-cylinder in communication and to place the brake-cylinder and exhaust in connection, a cam common to said valves and adapted to actuate them, and means for turning the cam, substantially as set forth.

16. In a huid-pressure brake the combination with a brake-applying means, of a compressor or pump communicating with the same, mechanical connections for actuating the pump from a suitable motor such as the vehicle-axle, a fluid-pressure device controlling said mechanical connection, and avalve controlling the communication between the compressor and the brake-applying means and also independently controlling said fluidpressure device, said valve comprising a casing, three independent valves within the same and a cam for actuating said valves at predetermined times, substantially as set forth. In witness whereof I have hereunto signed my name in the presence of two witnesses.

HENRY L. HOWE. Witnesses Gno. H. GRAHAM, MAX O. BEARD.

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