US2229503A - Sanding control means - Google Patents

Description

Jan. 21, 1941. E. E. HEWITT ETIAL 2,229,503

SANDING CONTROL MEANS Filed April 30, 1940 INVENTORS ELLIS E.HEWITT EVERETT FESEXTON BY We I [Q ATTORNEY Patented Jan. 21, 1941 UNETED STATES FPATENT OFFECE SANDING CONTROL Ii IEAN S Application April 30, 1940, Serial No; 332,430

17 Cia-ims.

This invention relates to sanding apparatus and more particularly to the type for use on railway vehicles for sanding track rails.

In order to decelerate or stop modern high speed railway vehicles and trains in the relatively short distances required to meet operating schedules and to insure the safety of the trains, it is necessary to employ high braking forces upon'the vehicle wheels. To avoid slipping or sliding of the wheels on the rails due to such braking forces it is usually desirable to provide sand on the rails to obtain a maximum and substantially uniform degree of adhesion between the wheels and rails, regardless of the condition of the track rails.

Sanding arrangements heretofore employed on railway vehicles have generally been designed to provide a substantially constant rate of flow of sand for sanding purposes. The same amount of sand has been thus provided for sanding the track rails when the vehicle is operating at a high speed as when operating ata lower speed and obviously, if the amount of sand is adequate for maximum speed it is excessive for the lower speeds. This naturally results in the wasting of sand at the lower speeds and necessitates carrying greater amounts of sand on the vehicles than would otherwise be required. Furthermore, excessive use of sand on rails is unnecessary, and under certain conditions is undesirable, as for instance it tends to interfere with the signal systems employed on railroads.

The principal object of the present invention is therefore to provide an improved sanding arrangement for use on railway vehicles which is adapted to provide sand for sanding a track railin an amount which is substantially proportional to the speed at which the vehicle is operating, whereby substantially the same amount or same deposit of sand will be provided on a unit length of track rail for all train speeds.

Other objects and advantages will be apparent from the following, more detailed description of the invention.

In the accompanying drawing, the single figure is a diagrammatic view, partly in section and partly in outline, of a portion of a railway vehicle brake equipment and the improved sanding arrangement.

The parts of the fluid pressure brake equipment shown in the drawing for illustrating a use of the invention may be the same as corresponding parts of the brake equipment disclosed in Patent No. 2,173,938 issued to Ellery R. Fitch on September 26, 1939. As shown, the brake equipment comprises a brake control valve device I, a

speed governor device 2, a pneumatic switch device 3, a source of electric current such as a battery 4, a main reservoir 5 normally charged with fluid under pressure in the usual manner, a main reservoir pipe 6 connected to the main reservoir 5 and supplied with fluid under pressure therefrom, a supply reservoir 1 which is normally charged with fluid under pressure from the main reservoir 5 by way of the main reservoir pipe 6 and through a check valve device 8, a straight air pipe 9 to which fluid under pressure is adapted to be supplied for eiiecting an application of brakes on the vehicle and from which fluid under pressure is adapted to be released for effecting a release of brakes on the vehicle in any suitable manner or by any desired means (not shown) and a brake cylinder device 10 adapted to be operated by fluid under pressure for applying the brakes on a vehicle to a degree dependent upon the pressure of fluid supplied thereto.

According to the invention there is associated with this brake equipment, the improved sanding arrangement comprising a sand control valve device II, a sanding device l2 through which the flow of fluid under pressure is adapted to supply sand for sanding a track rail in an amount proportional to the amount or pressure of the fluid supply, a sanding reservoir l3, and an electromagnet device M which may be controlled in any desiredmanner as by means of a manually closed self opening switch [5.

The brake control valve device I is provided to operate upon the supply and release of fluid under pressure to and from the straight air pipe 9 to effect the supply and release of fluid under pressure to and from the brake cylinder device 1'0 by way ofa brake cylinder pipe 16 for effecting an application and a release of brakes on the vehicle, respectively, and comprises valve means controlled in accordance with the selective operation of high, medium, and low speed electromagnet devices l1, l8 and I9, to limit the pressure obtainable in the brake cylinder device IB to different maximum degrees when the maximum pressure is provided in the straight air pipe 9.

Both the high and medium speed electromagnet devices H and I8 are adapted to be energized when the vehicle is operating above a certain high speed limit, such as sixty miles per hour, so that the brake control valve device I will provide substantially the same pressure in the brake cylinder device H] as provided in the straight air pipe 9 in order to obtain a desired maximum degree of braking which is considered permissible above this speed limit Without danger of causing sliding of the vehicle wheels.

Below the high speed limit of sixty miles per hour and above a medium speed limit of the vehicle, such as forty miles per hour, only the medium speed magnet I3 is adapted to be energized under which condition the brake control valve device I is adapted to operate to limit the maximum pressure obtainable in the brake cylinder device I to a lower degree than above the higher speed limit, but which is considered the maximum permissible for use in this speed range without danger of causing sliding of the vehicle wheels.

Below the medium speed limit of forty miles per hour and above a low speed limit such as twenty miles per hour, all of the electromagnet devices to I9 are adapted to be deenergized, under which condition the brake control valve device I is adapted to operate to limit the maximum pressure obtainable in the brake cylinder device It to a still lower degree which however is considered the maximum permissible for use in this speed range to avoid sliding of the vehicle wheels.

Below the low speed limit of twenty miles per hour the low speed electromagnet device I9 is adapted to be energized and under this condition the brake control valve device I is adapted to limit the maximum pressure obtainable in the brake cylinder device I0 to a still lower degree which however is considered the maximum permissible to avoid the possibility of sliding of the vehicle wheels.

It will therefore be evident that the maximum. pressure of fluid which it is possible to obtain in the brake cylinder device I0 depends upon the speed at which the vehicle is operating and is greatest when the speed is above a certain high speed limit and least when below a certain low speed limit, and therefore through the medium. of the control valve device I as governed by the high, medium and low speed electromagnet devices, the maximum pressure obtainable in the brake cylinder device will be varied substantially in proportion to the speed of the vehicle.

For the sake of simplicity in the present application and in View of the fact that reference may be had to the above referred to patent a more detailed description of the brake control valve device I in the present application is not deemed essential.

The speed governor device 2 is provided for controlling the energization and deenergization of the electromagnet devices I'I, I8 and I9 in accordance with the speed of the vehicle and comprises a stationary casing 22 secured to any suitable part of the vehicle. A drive shaft 23 journaled in the governor casing 22 is secured. to any suitable part of the vehicle (not shown) which rotates upon movement of the vehicle along the track rail, whereby said shaft will. rotate at a speed proportional to the vehiclespeed.

In the casing 22 the drive shaft 23 is connected to a centrifuge head 24 carrying two oppositely arranged bell cranks 25, each of which is pivotally mounted on a pin 26 secured in the head 24-. Each of the bell cranks 25 is provided with an arm extending in a generally outwardly direction and provided at its end with a governor weight or mass 21 and also has an arm extend ing in a generally upwardly direction and engaging a plate 23 which is subject on the oppo-- site face to the pressure of a control spring 29.

The plate 28 is provided on the lower end of a shaft 30 which is mounted to slide in a bore provided through the casing 22. On the outer end of rod 3|] there is fixed a switch contact 3| and slidably mounted on the rod between the contact 3| and the casing are two contacts 32 and 33, all of which contacts are suitably insulated from the shaft 39 and from each other. The shaft 30 has an annular collar 34 arranged between the contacts 32 and 33 and interposed between this collar and contact 32 is a spring 35. At the opposite side of contact 32 the shaft 3|! has a collar 36 adapted to engage the contact for moving same in a downwardly direction. A spring 31 is interposed between the collar 34 and one side of the contact 33 while at the opposite side of said contact the shaft 30 has a collar 38 for actuating same.

The contact 3| is provided for connecting in circuit closing relation two contact fingers 48 and 4|, the finger 46 being connected to a current supply wire 42, while the finger 4| is connected to a train wire 43 to which one terminal of the high speed electromagnet device I1 is connected. The other terminal of the magnet device I! is grounded.

The governor contact 32 is provided for connecting in circuit closing relation two contact fingers 45 and 46, the finger 45 being connected to the current supply wire 42, while the finger 46 is connected to a train wire 4'! to which one terminal of the medium speed electromagnet device IB is connected, such magnet device having its other terminal grounded.

The governor contact 33 is pro-vided for connecting in circuit closing relation two contact fingers 49 and 50, the finger 49 being connected to the current supply wire 42, while the finger 50 is connected to a train wire 5| to which one terminal of the low speed electromagnet device I9 is connected while the other terminal of said magnet device is connected to ground.

I In the drawing the parts of the governor device are shown in the positions which they will occupy when the vehicle is operating above the high speed limit. Under this condition it will 'be noted that the governor contacts 3| and 32 connect the current supply wire 42 to the train wires 43 and 41 for effecting energization of both the high and medium speed electromagnet devices I1 and I8. When the speed of the vehicle is reduced below the high speed limit, the action of centrifugal force on the governor weights 2'! becomes reduced sufiiciently for spring 29 to :move the shaft 3|] downwardly to a position for w pulling the contact 3| out of engagement with fingers and 4| to thus effect deenergization of the high speed electromagnet device I]. However, the contact 32 is maintained in engagement with fingers 45 and 46 by spring 35 until the speed of the vehicle becomes reduced to the medium speed limit. Thus between the high .and medium speed limits the medium speed electromagnet device I8 will be energized, while the .high and low speed electromagnet devices will be 'deenergized.

When the speed of the vehicle is reduced below the medium speed limit, the collar 35 on the :shaft 30 engages the contact 32 and pulls same out of engagement with the fingers 45 and 46,

:and the contact 33 remains out of engagement with the fingers 49* and 50 until the low speed limit is obtained. Thus in the range of speed between the medium and low speed limits all of theeIectrOmagnet devices H to IE? will be deenergized. When the low speed limit is obtained the contact 33- moves into contact with fingers 4,9 and 50 for supplying electric current to the low speed magnet I9 to effect energization thereof and for maintaining same energized throughout further deceleration of the vehicle.

It will thus be apparent that the speed governor device 2 is operable tocondition the high, medium and low speed electromagnet devices II, I8 and I9 to cause the brake control valve device I to. operate in effecting an application of brakes, as before described, to limit the maximum degree of pressure obtainable in the brake cylinder device II) in accordance with differentspeeds or speed ranges of the vehicle, or in other words substantially in proportion to the vehicle speed.

The pneumatic switch device 3 is provided for connecting the battery 4 to thecurrent supply wire 42 at the time an application of the brakes is initiated and to maintain such connection until a subsequent, substantially, complete release of brakes is effected and comprises a casing containing a piston 52 having at one side a chamber 53 connected by a pipe 54 to the straight air pipe 9. The piston 52 has a piston stem 55 extending through a chamber 56 at the opposite side of the piston and is provided outside of the casing with a suitably insulated contact 51 which is adapted to connect in circuit-closing relation a pair of contact fingers 58 and 59. The finger 58 is connected by a wire 60 to one terminal of the battery 4 which has its othen terminal grounded. The finger 59 is connected to the current supply wire 42 of the speed governor device 2.

When fluid under pressure is supplied to the straight air pipe 9 to initiate an application of brakes on the vehicle, this pressure acts through the pipe 54 in chamber 53 of the switch device 3 and is adapted to effect movement of the piston 52 and thereby of the contact in an outwardly direction and into circuit-closing relation with the contact fingers 58 and 59. In chamber 56 there is provided a spring 6| acting on the piston in opposition to the pressure of fluid in chamber 53. The pressure of this spring is relatively light so that the switch device will operate to connect the battery to the speed governor device as soon as an application of brakes is initiated as just mentioned and is adapted to operate upon a substantial complete release of brakes on the vehicle, as determined by the reduction in pressure in the straight air pipe 9 to a low degree, to return the piston 52 and contact 51 back to their normal position shown for thereby cutting off the supply of current from the battery 4 to the speed governor device while the brakes on the vehicle are released.

The sand control valve device II comprises a casing containing a piston 62 having at one side a chamber 63 which is in constant communication with a volume or chamber 64. At the opposite side of the piston there is provided a chamber 65 which is open to a pipe 66. A partition wall 61 separates the chamber 65 from a chamber 68 which is connected to an outlet pipe 69. The piston 62 has a stem H! which extends through the chamber 65 and a suitable bore in the wall 61 into chamber 68, there being a sliding flt between said stem and the wall of said bore. In chamber 68 a valve 1| is provided on the end of stem for cooperation with a valve seat provided in, the casing, said valve being arranged to control communication between a pipe I2, which is constantly supplied with fluid under pressure from the supply reservoir 1, and the chamber 66. A spring I3 in chamber 63 acts on the piston 62' for normally holding said piston in the position shown to seat the valve II. The outlet pipe 59 is connected directly to the pneumatically operative sanding device I2 and also to the sanding reservoir I5 through a choke I4.

The electromagnet valve device I4 is provided for controlling communication between the pipe 66 and the brake cylinder pipe I6 and comprises an electromagnet arranged to control a pair of oppositely seating coaxially arranged valves 76 and I7. The valve 16 is provided for controlling communication between a chamber I8 and a chamber 19 which is open to the atmosphere through a port 80, while valve 1! is arranged to control communication between chamber 18 and. a chamber 8| which is in constant communication with the brake cylinder pipe I6. When the electromagnet E5 is energized, the valve I6 is adapted to be seated and the valve I1 unseated so that fluid under pressure may flow from the brake cylinder pipe I6 to the pipe 66. A spring 82 in chamber BI is adapted to act upon denergization of the electromagnet I5 to seat the valve TI and to unseat the valve I6 for thereby opening the pipe 66 to the atmosphere.

One terminal of the electromagnet T5 is connected to ground while the other terminal is connected to a train wire 83. The switch device I5, which for the purpose of illustration may be manually operated, is adapted when subject to manual pressure to connect the battery supply wire 60 to the train wire 83 for thereby supplying electric current from the battery 4 to the electromagnet I5 for effecting energization thereof.

Whenever the electromagnet T5 is energized and fluid under pressure is supplied to the brake cylinder device it! for applying the brakes on the vehicle, fluid at the same pressure'as acting in the brake cylinder device is adapted to flow from the brake cylinder pipe I6 through the electromagnet device l4 and pipe 66 into chamber 55 at one side of piston 62 for eiTecting movement of said piston in the direction of the right hand against the opposing pressure of spring I3 for unseating the valve H. The pressure of spring 73 on piston 62 is relatively light so the valve II will be thus unseated promptly upon initiating the application of brakes on the vehicle.

The piston 62 has a restricted port 84 connecting chamber 65 to chamber 63 and through this port fluid under pressure is adapted to flow to the chambers 63 and 64 when fluid under pressure is supplied to the chamber 65. The flow capacity of port 84 is so related to the combined volume of chambers 63 and 64 that after a certain chosen interval of time, such as three to five seconds, from the time that fluid under pressure is supplied to chamber 65, the pressure of fluid will build up in chambers 63 and 64 to a degree sufficient to permit spring I3 to return the piston 62 to its normal position for thereby moving the valve II back to its seated position.

The length of time which the valve II will be held unseated by brake cylinder pressure in chamber 65 acting on the piston 62 will be greatest when the brake cylinder pressure is highest as provided for braking the vehicle above the high speed limit above mentioned, and will be least when the brake cylinder pressure is limited to its lowest degree permissible when braln'ng the train below the low speed limit above mentioned. It will therefore be apparent that the valve M will be held open for a period of time dependent upon the degree of brake cylinder pressure and since, as above described, the brake cylinder pressure is adapted to be limited or varied in accordance with the speed at which the vehicle is operating it will be apparent that the valve H will be held unseated for a period of time which will also be in proportion to the speed at which the vehicle is operating at the time an application of brakes is initiated.

When the valvev 1| is unseated by the piston 52 fluid under pressure is adapted to flow from the supply reservoir Iv through the pipe 12 to the pipe 69 and thence directly to the sanding device l2 and also through the choke 14 to the sanding reservoir IS. The flow capacity of the communication past the valve H to pipe 69 is such that with said valve open substantially the same pressure will be obtained in said pipe as acting in the supply reservoir 1 and this prompt, relatively high pressure supply directly to the sanding device I2 is adapted not only to initiate prompt blowing of sand from said device for effecting sandin of the track rail, but also is adapted to act as a cleanin blast for clearing the usual sand pipe (not shown) of ice or other obstructions, in the usual manner.

A portion of the fluid thus supplied to the pipe 69 is adapted to flow through the choke 14 to the sand reservoir I3 for charging same. As above mentioned, the valve H is held open only for a relatively short period of time, depending upon the degree of brake cylinder pressure and hence the speed at which the vehicle is operating, and during this period of time the sand reservoir [3 will therefore become charged to a pressure depending upon how long the valve II is maintained in its open condition. With the valve H held open for a relatively long period of time as when the vehicle is operating above the high speed limit the reservoir l3 will therefore become charged to a relatively greater pressure than when held open for a shorter period of time as when the vehicle is operating at a slower speed. In other words, due to choke M the reservoir [3 will become charged to a pressure which depends upon and which will vary in accordance with the interval of time the valve H is open, and since such interval of time is adapted to vary in accordance with the degree of brake cylinder pressure and therefore the speed of the vehicle, the reservoir l3 will become charged with fluid at a pressure which will be substantially in proportion to the speed of the vehicle.

Itwill be noted that this improved sanding arrangement provides for prompt supply of sand to the track rails as soon as an application of brakes is initiated, assuming that the electromagnet 15 is energized at this time,-and it also provides for a sudden but limited blast of air through the sanding device l2 for cleaning the usual sand pipes and furthermore, it provides for charging of the sanding reservoir l3toapressure which is proportional to the speed at which the vehicle is operating at the time.

After the valve H is seated fluid under pressure then flows from the'sanding reservoir l3 through choke 14 back to pipe 69 and through the. sanding device l2 for blowing sand therefrom for continuing the supply of sand to the track rail. The rate at which sand will be supplied from the sanding device I 2 to the track rail depends upon the pressure of fluid obtained in the sanding device from the reservoir 13 and this pressure will reduce as the pressure in the reservoir reduces by flow through said device.

The volume of reservoir [3 and the size of choke 14 are so related to each other and to thefluid pressure requirements of the sanding device l2 as to provide for a reduction in fluid pressure in the reservoir and thereby in the sanding device at a rate substantially in proportion to the deceleration or reducing speed of the vehicle caused by the maximum degree of brake application permissible for the speed at which the vehicle is operating. By thus reducing the pressure of fluid supplied to the sand device I2 in proportion to the reduction in vehicle speed the quantity of sand which will be blown from the sand device to the track rail will be varied in like proportion and will provide a desired'uniform degree of sanding of the track rail regardless of the speed at which the vehicle is oper-.

ating.

The volume of the reservoir I3 is also such that at substantially the time the vehicle is brought to a stop the pressure of fluid in the reservoir will be diminished to such an extent as to be insuiflcient to cause further flow of sand from the sand device l2, thus terminating the supply of sand for sanding the rails substantially at the time the vehicle is brought to a stop".

By thus varying the rate of sand supply in proportion to the vehicle speed and terminating such supply substantially at the time the vehicle is brought to a stop, undue wasting of sand is avoided, as will be apparent.

In order that the rate of sand supply to the track rail will vary substantially in proportion to the speed at which the vehicle is operating the engineer must, in the illustrative embodiment, operate the switch device 15 to effect energization of the electromagnet device M promptly upon initiating an application of brakes on the vehicle and maintain the switch in this condition for a period of time suificient to permit charging of the sanding reservoir l3, as above described. This period of time is however relatively short varying for instance from five to three seconds for the highest and lowest speeds-at which the vehicle may be operating at the time the application of brakes is initiated. After the valve H has been seated at the termination of this interval of time the engineer may then release the switch 15, as will be apparent.

If the rail conditions are such as not to require sanding the switch device 15 need not be operated by the engineer, in which case sand will not be supplied to the track rail and thus wasted.

Summary It will now be apparent that we have provided a relatively simple mechanism for use with fluid pressure brake equipment for supplying sand for sanding a track rail in an amount proportional to the degree of brake application on the vehicle, and since the degree of brake application is varied substantially in proportion to the speed at which the vehicle is operating, the amount of sand supplied for sanding purposes will likewise be varied substantially in proportion to the vehicle speed, so as to thus minimize excess and unnecessary use of sand and also the amount of sand which it is necessary to carry on a vehicle for sanding purposes for a certain length of tripof the vehicle.

While one illustrated embodiment of the invention has been described in detail it is not the intention to limit the scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. A sanding arrangement for sanding a rail under a railway vehicle comprising sanding means including a reservoir and means for venting fluid under pressure from said reservoir at a rate in proportion to a desired rate of deceleration of the vehicle, said sanding means being operative to supply sand for sanding said rail in a quantity proportional to the pressure of fluid in said reservoir, valve means operative to supply fluid under pressure to said reservoir, and means controlled by the speed of the vehicle for controlling said valve means and operative to actuate said valve means to limit the pressure of fluid supplied to said reservoir to a degree in proportion to the vehicle speed.

2. In combination, sanding means including a reservoir, means controlled by the speed of a vehicle and responsive to an application of brakes on the vehicle to charge said reservoir with fluid at a pressure proportional to the speed of the vehicle, said sanding means including means for supplying sand for sanding a rail under the vehicle in a quantity proportional to the pressure of fluid in said reservoir and means for reducing the pressure of fluid in said reservoir in proportion to the reduction in speed of the vehicle.

3. A sanding arrangement for sanding a rail under a railway vehicle comprising a reservoir from which fluid under pressure is adapted to be operative in accordance with the speed of the vehicle to limit the pressure of fluid supplied to said reservoir by said valve means to a degree proportional to the vehicle speed, and means for venting fluid under pressure from said reservoir and for supplying sand for sanding said rail at a rate in proportion to the pressure of fluid in said reservoir.

4. A sanding arrangement for sanding a rail under a railway vehicle comprising sander means from which sand for sanding said rail is adapted to be blown by fluid under pressure in a quantity which is proportional to the pressure of such fluid, a reservoir from which fluid under pressure is adapted to be vented through said sanding means, valve means for supplying fluid under pressure to said reservoir, and means operative in accordance with the speed of the vehicle for actuating said valve means to limit the pressure of fluid supplied to said reservoir to a degree in proportion to said speed.

5. A sanding arrangement for sanding a rail under a railway vehicle comprising in combination, a brake cylinder device, valve means for supplying fluid under pressure to said brake cylinder device to efiect an application of brakes on the vehicle, means controlled by the speed of the vehicle for effecting operation of said valve means to limit the pressure of fluid supplied to said brake cylinder device to a degree in proportion to the speed of the vehicle, and

sanding means including a reservoir, means for supplying sand for sanding said rail in a quantity proportional to the pressure of fluid in said reservoir, means for reducing the pressure of fluid in said reservoir in proportion to a desired rate of deceleration of the vehicle, and means operative automatically upon the supply of fluid under pressure to said brake cylinder device to charge said reservoir with fluid at a proportional pressure.

6. A sanding arrangement for sanding a rail under a railway vehicle comprising in combination, a brake cylinder device, valve means for supplying fluid under pressure to said brake cylinder device to effect an application of brakes onthe vehicle, means controlled by the speed of the vehicle for controlling said valve means and operative to efiect operation of said valve meansto limit the pressure of fluid supplied to said brake cylinder device to a degree in proportion of the speed of the vehicle, sanding means through which fluid under pressure is adapted to flow for supplying sand to said rail in a quantity proportional to the pressure of fluid supplied thereto, a reservoir for supplying fluid under pressure to said sanding means, and valve means operative upon supply of fluid under pressure to said brake cylinder device to charge said reservoir with fluid at a pressure proportional tothe pressure of fluid in said brake cylinder device.

'7. A sanding arrangement for sanding a rail under a railway vehicle comprising sanding means from which sand for sanding said rail is adapted to be blown by fluid under pressure supplied thereto in a quantity proportional to the pressure of such fluid, a reservoir from which fluid under pressure is adapted to be supplied to said sanding means, valve means for supplying fluid under pressure to said reservoir, and means conditionable in accordance with the speed of the vehicle for controlling said valve means and operative automatically to actuate said valve means to cut off the supply of fluid under pressure to said reservoir whenthe pressure of fluid in the reservoir is increased to a degree in proportion to the speed of the vehicle.

8. A sanding arrangement for sanding a rail under a railway vehicle including a reservoir, means for venting fluid under pressure from said reservoir to eflect a flow of sand to said rail in a quantity proportional to the pressure of fluid in said reservoir, valve means for supplying fluid under pressure to said reservoir, control means for effecting operation of said valve means to supply fluid under pressure to said reservoir and conditionable automatically to limit the pressure of fluid supplied to said reservoir to a degree in proportion to the speed of the vehicle, and mechanism operative in accordance with the speed of the vehicle for controlling the operation of said control means.

9. A sanding arrangement for sanding a rail under a railway vehicle comprising a reservoir, means for venting fluid under pressure from said reservoir to effect a flow of sand to said rail for a period of time in proportion to the pressure of fluid in said reservoir, valve means for supplying fluid under pressure to said reservoir, and means for effecting operation of said valve means to supply fluid under pressure to said reservoir and conditionable automatically in accordance with the speed of the vehicle to limit the pressure of fluid supplied thereto to a degree in proportion to the speed of the vehicle.

10. A sanding arrangement for sanding a rail under a railway vehicle comprising a reservoir, means for venting fluid under pressure from said reservoir to effect a flow of sand from said sander means in a quantity which is proportional to the pressure of fluid in said reservoir, valve means for supplying fluid under pressure to said reservoir, a movable abutment for controlling said valve means and having at one side a chamber to which fluid under pressure is adapted to be supplied for eiTecting operation of said abutment to operate said valve means to supply fluid under pressure tosaid reservoir, means conditionable in accordance with the speed of the vehicle to supply fluid to said chamber at a pressure proportional to the vehicle speed, and means operative automatically in accordance with the pressure of fluid supplied to said chamber to actuate said valve means to cut oil the supply of fluid under pressure to said reservoir an interval of time after the supply of fluid to the reservoir is initiated which interval of time varies in proportion to the pressure of fluid supplied to said chamber.

11. A sanding arrangement for sanding a rail under a railway vehicle comprising a reservoir, means for venting fluid under pressure from said reservoir to effect a flow of sand for sanding said rail in a quantity proportional to the pressure of fluid in said reservoir, a valve for supplying fluid under pressure to said reservoir, a movable abutment having at one side a chamber and at the opposite side a timing volume, means controlled by the speed of the vehicle and operative to supply fluid to said chamber at a pressure in proportion to the vehicle speed for actuating said abutment to open said valve for supplying fluid under pressure to said reservoir, a spring for actuating said abutment to close said valve, and means for supplying fluid under pressure to said timing volume at a restricted rate at the same time fluid under pressure is supplied to said chamber for rendering said spring eflective an interval of time after the supply of fluid under pressure to said chamber is initiated, said interval of time varying in proportion to the pressure of fluid supplied to said chamber forthereby varying the pressure of fluid obtained in said reservoir by operation of said valve in accordance with the speed of the vehicle.

12. A sanding arrangement for sanding a rail under a railway vehicle comprising sanding me ns from which sand is adapted to be blown by fluid in a quantity in proportion to the pressure of said fluid, a sanding reservoir from which fluid under pressure is adapted tobe vented through s id sander means, valve means operative to supply fluid under pressure to said sanding means and to said reservoir, a choke arranged to restrict the flow of fluid from said Valve means to said reservoir but not from said valve means to said sanding means, a movable abutment for controlling said valve and having at one side a chamber and at the opposite side a timing volume, means conditionable in accordance with the speed of the vehicle for supplying fluid to said chamber at, a pressure which varies according to the vehicle speed to actuate said abutment for opening said valve to supply fluid under pressure to said sanding means and to said reservoir, 'a spring for actuating said abutment to close said valve, and arestricted communication connecting said means and timing volume through which said timing volume is adapted to be charged with fluid under pressure at a relatively slow rate upon the supply of fluid under pressure to said chamber for rendering said spring effective a predetermined interval of time after the supply of fluid under pressure to said chamber is initiated, which time interval varies in proportion to the pressure of fluid supplied to said chamber.

13. A sanding arrangement for sanding a rail under a railway vehicle comprising sanding means, a valve for supplying fluid under pressure to said sanding means for blowing sand therefrom to effect sanding of the track rail, a movable abutment having at one side a chamber and at the opposite side a timing volume and operative upon supply of fluid under pressure to said chamber to actuate said valve for supplying fluid under pressure to said sanding means, means conditionable in accordance with the speed of the vehicle to supply fluid under pressure to said chamber at a pressure proportional to the Vehicle speed, a spring acting on said abutment for closing said valve, and a restricted communication connecting said chamber and timing volume through which the pressure of fluid in said volume is adapted to be increased at a relatively slow rate upon the supply of fluid under pressure to said chamber for rendering said spring efiective to close said valve, said restricted communication and timing volume being effective to vary the interval of time between the opening and the closing of said valve in proportion to the pressure of fluid supplied to said chamber.

14. A sanding arrangement for sanding a rail under a railway vehicle comprising sanding means, a valve for supplying fluid under pressure to said sanding means for blowing sand therefrom to ef fect sanding of the track rail, a movable abutment having at one side a chamber and at the opposite side a timing volume and operative upon supply of fluid under pressure to said chamber to actuate said valve for supplying fluid under pressure to said sanding means, means conditionable in accordance with the speed of the vehicle to supply fluid under pressure to said chamber at a pressure proportional to the vehicle speed, a spring acting on said abutment for closing said valve, and a restricted communication connecting said chamber and timing volume through which the pressure of fluid in said volume is adapted to be increased at a relatively slow rate upon the supply of fluid under pressure to said chamber for rendering said spring effective to close said valve, said restricted communication and timing volume being efiective to vary the interval of time between the opening and the closing of said valve in proportion to the pressure of fluid supplied to said chamber, and valve means controlling communication through which fluid under pressure is adapted to be supplied to said chamber, and means controlling said valve means to either open or close said communication to thereby render said abutment either operable or non-operable to unseat said valve. I 15. In combination, a brake cylinder devic valve means operable to supply fluid under pressure to said brake cylinder device for efiecting an application of brakes on the Vehicle, means conditionable automatically in accordance with the speed of the vehicle for controlling said valve means to limit the pressure of fluid supplied to said brake cylinder device to a degree in proportion to the vehicle speed, a sanding arrangement comprising a valve for supplying fluid under pressure to effect sanding of the rail under the vehicle, a movable abutment for controlling the operation of said valve, said abutment having at one side a chamber open to said brake cylinder device and to which fluid at brake cylinder pressure is adapted to be supplied for actuating said abutment to open said valve, a spring for actu ating said abutment to close said valve, and a timing volume at the opposite face of said abutment open to said chamber through a restricted communication through which said volume is adapted to be charged with fluid under pressure at a restricted rate for rendering said spring operative to actuate said abutment to close said valve an interval of time after the supply of fluid under pressure to said chamber is initiated which interval of time varies in accordance with the degree of pressure supplied to said brake cylinder device.

16. In combination, a brake cylinder device, valve means operative to supply fluid under pressure to said brake cylinder device, mechanism conditionable automatically in accordance with the speed of the vehicle controlling the operation of said valve means for limiting the pressure of fluid supplied to said brake cylinder device to a degree in proportion to the degree of vehicle speed, sanding means, a reservoir from which fluid under pressure is adapted to be vented to effect the flow of sand from said sanding means in a quantity proportional to the pressure of fluid in said reservoir, a valve for supplying fluid under pressure to said reservoir, a movable abutment for controlling said valve and having at one side a chamber adapted to be connected with said brake cylinder device and having at the opposite side a timing volume communicating with said chamber through a choke, and being operative by the pressure of fluid in said chamber upon the supply of fluid under pressure to said brake cylinder device to actuate said abutment to open said valve for supplying fluid under pressure to said sanding means and reservoir, means for actuating said abutment to close said valve, the flow capacity of said choke being so related to the size of said timing volume that a certain interval of time after the supply of fluid under pressure to said chamber is initiated the pressure in said volume will be increased to a degree for rendering said means operative to actuate said abutment to close said valve, said interval of time varying in proportion to the pressure of fluid supplied to said chamber and that acting in said brake cylinder device whereby the pressure of fluid obtained in said reservoir during the interval of time said valve is open is in proportion to the pressure of fluid in said brake cylinder device and thereby to the speed of the vehicle.

17. A sanding arrangement for a rail under a railway vehicle comprising a pipe through which fluid under pressure is adapted to flow for efiecting a flow of sand to said rail in a quantity which is proportional to the pressure of fluid supplied to said pipe, a fluid pressure supply reservoir, a sanding reservoir connected to said pipe through a restricted communication adapted to restrict the flow of fluid under pressure from said pipe to said sanding reservoir, valve means operative to open communication between said supply reservoir and pipe for supplying fluid under pressure to said pipe and at the same time through said restricted communication to said sanding reservoir for charging same, means controlled by the speed of the vehicle controlling said valve means and operative to actuate same to out oi? the supply of fluid under pressure to said pipe and sanding reservoir after an interval of time which varies in proportion to the vehicle speed.

ELLIS E. HEWITT. EVERETT P. SEXTON.

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