US801045A - Valve. - Google Patents

Description

PATENTED 001. a, 1905.

A. I. PERRY.

VALVE.

APPLICATION I'ILED 1120.21. 1904.

Tzg. 1

I IV V E IV TOR n%'*]ur I. Perry ATTORNEYS UNITED STATES PATENT OFFICE.

VALVE.

Specification of Letters Patent.

Patented Oct. 3, 1905.

' Application filed December 21, 1904. Serial No. 237,809.

To all whom, it may concern.-

-the city of New York, borough of Brooklyn, in the county of Kings and State of New York,

have invented a new and Improved Valve, of which the following is a full, clear, and exact description.

My invention relates to valves, and particularly to those applicable to the controlling of such fluid-pressure brakes as are used upon street-cars. Its principal objects are to provide means for applying the pressure proportionately to the movement of the valve-handle.

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 both views.

Figure 1 is a central vertical section through one embodiment of my invention, and Fig. 2 is a vertical sectional detail illustrating another form of the actuating-screw.

1O designates a casing in which are formed chambers 11 and 12, here shown as of cylindrical section and having open ends, the former being situated uppermost and being of greater transverse area. Near the lower portion of the casing about the chamber 12 is an annular enlargement 13, in which is a passage 14, communicating through ports 15 with the chamber. This passage 14: is connected to a source of fluid-pressure by some such means as a pipe or conduit 16. About the chamber 11, externally of the casing, is a similar enlargement l'T, containing a passage 18, from which exhaust-ports 19 open to the atmosphere, a pipe 20 serving to direct this exhaust to the desired point. Between these sets of ports is an admission-port 21, having a passage 21" leading from it and being connected by a pipe or conduit 22 to the brakecylinder or other mechanism to which pressure is to be supplied.

Operating within the casing is a valve-body 23, preferably of piston form and having a head 24: fitting within the chamber 11 and a lower head 25, which lies in the chamber 12. Between the two heads is a contracted portion forming an annular passage 26. If desired, the valve may be packed to prevent leakage, there being shown in the present instance a ring-27, surrounding the lower portion of the head 25, while above this is a ring 28, which in the normal position of the valve overlaps the supply-ports. A similar ring 29 extends about the head 24 and overlaps the exhaustports.

Extending vertically of the chamber 11, or along what is really an extension thereof, are ways 30 to receive projections 31 from a flange 32, surrounding the upper end of a nut or actuating member 33, which by its engagement with the casing is permitted to recipro cate longitudinally of said casing While being held against rotation therein. Into the lower portion of the nut a stem 34 is shown as threaded, it being conveniently secured in place by a lock-nut 35, which may contact with the bottom of the actuating-nut. The outer end of this stem projects through the upper extremity of the valve-body, which may rest upon an enlargement 36. Between the body and the flange of the actuating-nut is a spiral spring 37. Secured upon the top of the casing by some such means as bolts 37 is ahead 38, having a threaded bore which may lie within an outer boss 39 and receive a screw 40, which is provided within the casing with an opposite thread 40, engaging a threaded recess in the nut 33. The screw at its outer extremity may have a squared portion 4.1 to receive a hand lever or crank 42, which is shown as secured in place by a nut 43 and has a protecting shield or skirt 4.4 depending over the boss. A screw 45 may be threaded through the side of the casing with an end projecting into the valve-passage 26 to limit the movement of such valve in its chambers.

The lower end of the chamber 12, as illustrated, is closed by a head 46, in which are openings 17 to permit the free passage of air and avoid impeding the movement of the valvebody.

Considering that my improved valve is to be used in connection with car-brakes, the pipe 16 is joined to the reservoir charged by the air-pump, while the pipe 22 leads to the brakecylinder. The valve is shown as in its normal position, both the supply and exhaust being closed against communication with the brake-cylinder. To entirely open the valve, the lever is turned slightly to the left or anticlockwise, which rotates the screw, raising it in the head and at the same time causing the nut to travel up its lower threads. This opens communication between the admission-pipe to the brake-cylinder and the atmosphere and removes all pressure from the brake system. To apply the brake with any desired force up IIO to the maximum pressure of the supply, the I lever is moved in the opposite direction or to the right for the proper distance, the relation of the elements being preferably such that the full range of movement is through one hundred and eighty degrees. This simultaneously moves the screw and actuating-nut down, which would tend to compress the spring; but as there is no opposing force except a negligible frictional resistance the piston is forced with it, opening connection between the supplyports and the admission-port as soon as the ring 28 descends below the upper edge of the former ports. The air now flows to the brake-cylinder; but as the pressure increases its action upon the valve-heads (the upper of which has the greater effective area) exerts an upward force upon the spring and moves the piston against its tension until equilibrium is established, closing the supply-port and maintaining the pressure within the brake-cylinder to hold the brake-shoes against the car-wheels. If the lever is moved still farther to the right, the compression of the spring is increased and the supply-ports again opened, augmenting the pressure in the brake-cylinder in the same manner. This may be continueduntil at the extreme of lever movement the maximum force of the supply will have been exerted. To reduce the brake-pressure, the lever is turned more or less to the left, lifting the screw and actuating-nut and decreasing the compression of the sprin The fluid-pressure acting differentially upon the valve-heads forces said valve upwardly, opening the exhaust-ports and allowing escape to the atmosphere, thereby reducing the brake-pressure. As the force of the air is lessened the spring moves the piston down until equilibrium is attained. In the same manner additional reductions may be made. It will be evident that full brake-pressure may be secured by the extreme movement of the lever in one direction while complete, and immediate release will follow its movement to the opposite limit.

It will be seen that by the use of my im proved valve in connection with an air-brake the driver will have complete control without removing his attention from the track ahead, he being able to apply the brakes gradually in proportion to the lever movement for service stops or with full force in case of emergency, and that by shifting the lever slightly to any position and leaving it there a definite braliing force is secured and maintained until the lever is again moved. Furthermore, because of the relation of the ports to the valve-body its operation is unafi ected by variations in pressure in either the supply-reservoir or the brake-cylinder as long as the former does not fall below the desired maximum.

It will be obvious that instead of employing a diiferential screw for moving the actuatingnut, a simple screw, such as is shown at 28 l in Fig. 2 of the drawings, might be used, this having an unthreaded spindle 49, which is journaled in the upper casing-head. The effect will be the same; but the amount of movement of the nut for any particular angular movement of the lever will be decreased.

Having thus described myinvention, Iclaim as new and desire to secure by Letters Paton t 1. A valve COmDIlSiDQ, a casing having supply, admission and exhaust ports, and a movable body portion provided with opposite heads between which is a continuous space which may communicate with each of the ports, the pressure of the supply being applied only to the inner adjacent faces of the heads to efiiect movement of the body.

2. A valve comprising a casing having supply, admission and exhaust ports, and a movable body portion provided with opposite heads between which is a space which may communicate with each of the ports, said heads having different effective areas.

3. A valve comprising a casing having supply, admission and exhaust ports, a valve-body having a passage which may communicate with the ports, a movable actuating member, a stem along which the valve may move, said stem being secured to the actuating member and provided with an enlargement with which the body may contact, andp. spring interposed between the actuating member and body.

4. A valve comprising a casing having supply, admission and exhaust ports, a movable body portion provided with opposite heads between which is a space which may communicate with each of the ports, said heads having difierent efl ective areas, an actuating member connected with the movable body, and a spring interposed between the actuating member and body.

5. A valve comprising a casing having supply, admission and exhaust ports, a movable body portion provided with opposite heads between which is a space which may communicate with each of the ports, said heads having diiferent effective areas, an actuating member, a stem extending from the actuating member and being provided with an enlargement with which the body may contact, and a spring interposed between the actuating member and body.

6. A valve comprising a casing having supply, admission and exhaust ports, a valve-body having a passage which may communicate with the ports, a nut mounted to reciprocate in the casing, a stem connecting the valvebody and nut and upon which the former may move, a screw rotatable in the casing and engaging the nut, and means for turning the screw.

7. The combination with a casing having connecting-chambers of different areas and ports opening into the chambers, of a pistonvalve provided with a head fitting each chamber and a passage which may communicate with the ports, and an actuating member convalve, and a spring interposed between the T nected with the valve. actuating member and valve.

8. The combination with a casing having Intestimony whereoflhavesigned my name connecting chambers of different areas and to this specification in the presence of two sub= 5 ports opening into the chambers, of a pistonscribing Witnesses.

valve provided With a head fitting each cham- ARTHUR IRVING PERRY. her and a passage which may communicate Witnesses: with the ports, an actuating member sliding R. E. HAWLEY,

in the casing and being connected with the C. L. CARMAN.

Images