US 2196977 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
April 16, 1940- c. A. CAMPBELL Er AL 2,196,977
SANDER Filed June 21, 1957 :5 sheets-sheet 1 Gttornegs April 15, 1940. c. A. CAMPBELL ET AL .2,196,977
SANDER Filed June 21, 1937 3 Sheets-Sheet 2 April 16, 1940.
c'. A. CAMPBELL Er A1.
SANDER Filed June 21, 1937 3 Shets-Sheet 3 (Wm/Leva @.@m/mpbe/ 3g u. MGZ@ (lttornegs Patented Apr. 16, 1940 PATENT OFFICE SANDER Charles A. Campbell and Lewis A. Safford, Watertown, N. Y., assignors to The New York Air Brake Company, a corporation ot New Jersey Application June 21, 1937, serial No. 149,493
This invention relates to sanding devices for railway vehicles, and particularly yto sanding mechanisms intended for use with modern high speed trains.
The high speeds characteristic of stream-lined light weight trains have introduced a serious braking problem. The stopping distance must be kept within limits heretofore attained with slower trains in order to permit operation of the high speed trains with the existing signal spacing. To attain this result it is necessary to apply the brakes with an intensity which approaches the maximum permissible. In fact the brakes are controlled in response to the deceleration rate so that the initial application is severe, the brakes being gradually released by a decelerometer to maintain a substantially uniform deceleration rate until the train is brought nearly to rest, at which time the brakes are further released to permit a smooth stop.
In operating the brakes under such conditions the danger of loclnng a wheel and causing it to slide is substantial. If a wheel locks it cannot vbe released in time to prevent serious injury to 'the wheel. If rail conditions were uniform the operation of the brakes could be standardized with a safe margin, but rail conditions aresubject to wide variations because of rain, snow, sleet and various other uncontrollable factors. 'Ihe effects of rail conditions on brake performance are so great that a brake system which operates satisfactorily, and with a safe margin, under favorable rail conditions, may slide wheels under even moderately adverse rail conditions.
The problem therefore is to standardize the condition of the rail so that the variations encountered will be within the safe working limits of the brake system if set for good rail conditions.l
fore the braking pressure reaches a value which could cause sliding.
In sanding devices as heretofore used, the sand has been caused to trickle down a pipe impelled by a comparatively feeble jet of air. This is slow and often ineffective. With a train operating at 110 miles per hour, and with the possibility of cross winds, some more rapid and certain Way of insuring the entrance of the sand between the wheels and the rail is vitally necessary. Accord- 5 ingly, one of the features of the present invenvtion is the provision of means to blow the sand violently into the angle between the wheel and the rail, so violently that it is certain to arrive at the intended point of application.
To accomplish this result it is desirable to operate the sand traps and sander pipes under substantial pneumatic pressures, and since it is undesirable to operate the sand boxes under such pressure, an important feature of the present invention is an intercepter valve, which upon initiation of the sanding operation, disconnects the sand trap from the sander box.
This idea of pressure sanding has another very important aspect which is that the sandervnozzles are exposed and are likely to become clogged, particularly by mud, sleet or snow. An important feature of the present invention is the use of a distensible sander nozzle so designed that it will be markedly deformed under the sanding pressure used, and will serve to break away any obstructions, particularly ice or sleet. Distensibility has peculiar significance with the use of sanding pressures suflicient to produce substantial distension even when the nozzle is heavily coated with ice.
Another important feature of the invention is the arrangement of the ports in such a way that any sanding operation, whether it is initiated manually or automatically by the operation of the brake, will occur simultaneously in advance of every braked wheel. Means are provided to permit certain sanding units to be cut out if desired. For example, under favorable rail conditions it might be desirable to permit sanding under the leading wheels only.
For the reason that most stream-lined trains are operated in one direction, it is not ordinarily necessary on such trains to provide selective sanding according to the direction of travel. It 5 is well known, in the sanding art, to provide such selective sanding, controlled, for example,l by the reversing mechanism of the propelling unit. Such a device is applicable to the present invention by the adoption of means such as that de- 50 scribed in the patent to Schaake 758,194, April 26, 1904,l but this is not regarded as a feature of the present invention and hence need'not be illustrated. The system of v the present invention obviously can be so used.
The preferred embodiment of the invention will now be described in connection with the accompanying drawings, in which- Fig. 1 is a diagrammatic view, chiefly in section,
n showing the sander control mechanism for the train and the sander mechanism for one wheel.
Fig. 2 is a diagram showing the control connections for sanders throughout a train.
Fig. 3 is a vertical section of a sand trap constructed according to the present invention a'n showing its actual construction. f
Fig. 4 is a view half in elevation and half in section, of the sand trap shown in Fig. 3, the plane of section passing through the axis of stem 83 of the interceptingvalve.
Referring rst to Figs. 1 and 2, any suitable source of air under pressure is represented by the reservoir 6, assumed to be the main reservoir of the air brake system and 1 represents pipes directly connected thereto. s
Control of sanding is eiected by the sander valve generally indicated by the numer 8 applied to its body. This valve is substantially identical in structure, and identicalin function with that shown in the patent to Campbell 2,035,533, issued March 31, 1936. Reference may be made to that patent for details, and since the valve is illustrated here merely as typical control means, a brief description will suice.
A branch of pipe 1 leads to body 8, and a pipe 9 leadsI f rom the body to the motor chamber II of the sander switch whose body is indicated at I2. A timing reservoir I3 is connected with body 3 by pipe I4. A pipe I5 leads to body 8 from a brake valve (not shown) which in certain applications, for example emergency applications, supplies air under pressure to the space above piston I6. Piston valve I1 may be forced downward by this means or by hand button Iii.v
The sander control valve in body 8 is shown in Fig. 1 in normal (inactive) position. At such time the pipe 9 is vented to atmosphere through the choke I9 with which it is constantly in communication. and since the supply port 2! in valve housing 8 is blanked by the lower head of the piston valve I1, the space II below the motor piston of the sander switch is at atmospheric pressure.
'Iiming reservoir I3 is charged from pipe 1, past the reduced middle portion of valve I1 to pipe I4. Ii.' the valve I1 be moved downward either by the piston I6 or by the button I 9 the main reservoir connection 1 is blanked and the timing reservoir I3 is connected through pipe I4 and the reduced middle portion of valve I1 with theport 2l. This supplies air above a piston 22 which overpowers the return spring 23 so that the valve I1 remains in its lower position until timing reservoir pressure bleeds away through the choke I9. It should be explained that a branch of port 2I leads around the lower head of valve I1 to the pipe 9 and choke I9. Conseouently, the effeet of depressing the button I8 or the piston I 6 is to admit pressure uid to the space below vthe motor piston of the sander switch and to maintain this pressure for a time. determined by the capacity of choke I9 and the volume of the timing reservoir I3. When pressure in the timing reservoir is substantially depleted spring 23 willrestore the valve to normal position.
Ii' timed sanding is not desired, manuallvcontrolled sanding can be had b v depressing the button 24 which unseats the valve 25 and allows main reservoir air to ow via pipe 1 past the reduced portion vof valve I1, passage 26, valve 2l, and passage 21. to the branch of port 2|, and via pipe 9 to the space II. As long as button 24 is held depressed the sanding switch will be energized. 'I'hus the control valve, generally indicated at 6, provides for timed sanding say for sixty seconds. This may be manually initiated by depressing button I3 or may be automatically initiated by a brake application through the operation of the piston. I6. Sanding at will may be secured by depressing the button 24 and will continue as long as the button is held depressed and there is sand in the traps.
Referring now to the sander switch. The development of pressure in the motor chamber II below the piston 23 forces this up against the re"- sistance of the coil springs 29 causing a contacter head 3| to bridge the contacts 32 and 33. This energizes a sander circuit, represented by the battery 34 and the wires 35 and 36, which, as indicated in Fig. 2, extend throughout the train. The switchv 31 may be provided to cut out the rear sanding units of the train, if desired, but the normal position of the switch 31 is closed so that all the `sanders throughout the train will operate simultaneously.
The leading sanding unit on the train will now be described with reference to Fig. 1
. Connected between the wires 35 and 36 for- A ward of the switch 31, and hence not subject to y control thereby, is solenoid winding 33. When this winding is energized its armature is forced downward to close and exhaust poppet valve 39 and open an inlet poppet valve 4I controlling flow from main reservoir pipe 1. This motion is resisted by a coil compression spring 42. In a normal position, shown in Fig. 1 (winding 33 deenergized) valve 4I interrupts the supply of air from the main reservoir pipe 1 to branch pipe 43, and valve 39 vents branch pipe 43 to atmosphere.
When the solenoid is energized and the vent is closed, main reservoir air is admitted to the pipe 43. Pipe 43 leads to the space below the mit supplemental or cleaning air at high pressure and in large volume to the sand trap but only for a brief period. The clean out pipe connection is indicated at 52 and the clean out timing valve comprises a diaphragm 53 subject on its lower face to pressure in chamber 49 and subject on its upper side to the pressure oi' a coil compression spring54 assisted by the pressure in chamber 55 within cap or housing 56. There is a choke connection 51 from the space 49 to the chamber` 55. When pressure is admitted beneath diaphragm 44 valve 41 is unseated, and main reservoir pressure is immediately established in the chamber 49 but not. in the chamber 55 because of the delaying action of the choke 51. It follows that diaphragm 53 moves upward and then as pressure is equalized through the'choke 51 moves downward. Diaphragm 53 servesas a valvevin conjunction with the annular seat 53, to control flow to the clean out pipe 52. It follows that when pressure is .established in the chamber 49 ber 65 separated by the inclined partition 66 ex cept for opening 69. Sand supplied through the pipe 62 flows downward through the combined distensible approach 61 and valve seat 88 into the upper chamber 84 -and thence through port 69 to the lower chamber 65 where it accumulates behind a dam or crest 1i over which the sand must flow to enter the nozzle pipe 12. The nozzle pipe 12 leads to a fitting 13 on which is mounted a distensible nozzle 14 formed of resilient rubber or like material. This directs the discharging sand into the angle between the tread of the related wheel and the top 16 of the rail. The distensible approach 61 and the valve seat 68 are also formed of resilient rubber or similar material, and are held in place by a fitting 11 whose whichA the portion 61 Ymay be expanded or disl tended.
When the sander is out of action, said flows through the pipe 62 through the valve seat 68 into the upper chamber 84 from which it flows through the passage 69 into the lower 'chamber 65. Flow is arrested by the dam 1| at the angle of repose of the sand, so that between operations of the sanding device the sand trap receives the entire charge of sand to be used in the succeeding sanding operation.
The sanding jet pipe 5| leads to a passage 19 in which is mounted a small jet nozzle 8|. This delivers a jet of air beneath the partition 66 and substantially parallel thereto. v The jet stirs up the sand in the chamber 65 during the sandingr operation. The eect of this is to cause the sand to ow over the crest 1i where it enters the iniiuence of a second jet controlled by nozzle 8,2 and directed down the pipe 12. The nozzle 82 is screwed on to the lower end of a hollow stem 83 which passes through the passage 19 and is ported at 84 to communicate therewith so that when air is supplied to the pipe 5i it ows to both the jets 8| and 82. It also flows upward through an axial bore 85 into a flattened bulb 86 secured to a flange on the uppery end of the'stefn 83 by a nut 81 and bearer plate 88. A cup-like. valve element 89 is mounted over the bulb 86 and when this bulb is inflated the valve 89 yis moved upward to seal against the seat 68. Consequentlv when the sander comes into operation. the supply of sand is intercepted at the seat 88.
If the intercepting of the sand were all that were required -a relatively simple problem would be afforded, but it is necessary not only to intercept the sand but to produce an air-tight seal so that if substantial pressure is developed in the sand trap the sand boxes will be protected against backr flow. Sand flowing down through the approach 61 has a tendency to arch and resist closure of the valve 89. Thisr tendency, however, is defeated by the distension of the approach 61 into the space 18. In other words. the distensible approach offers-a pocketinto which edly that the obstruction is blown clear.
sand is forced to permit complete closure and air tight'seating of the valve.
The clean out air 52 vis delivered directly to the upper chamber 84 of the sand trap, entering adjacent the fitting 11 and is also delivered by way of the bypass 9| to the space around the nozzle 82. Thisspace is in direct communication with the lower chamber 65.
It follows that when the valve 41 is unseated air jets are delivered at the nozzles 8i and 82, the sand supply is intercepted at the valve seat 88 and a tight air seal is there produced. Air in large quantity is also delivered to both chambers of the trap and to the nozzle 14 for a short period. If the nozzle 14 is clogged by mud, ice, snow or sleet, it will be subject suddenly to'heavy internal pressure and will be distended so mark- If the sander nozzle is clearthe development of pressure within the sand trap and the nozzle will be less marked. In any case the sand will be delivered by a rapidly owing jet into the angle between the tread of the wheel and the rail.
Referring now to Fig. 2, the arrangement of the sanding units, other than the leading one, will be explained. The essential difference is that thesey Sanders do not derive their operating air directly from the main reservoir. It is not ordinarily convenient to run a main reservoir pipe throughout the entire length o'f the train. but there usually is a brake pipe or supervisory line which is normally charged to main reservoir pressure or to a pressure slightly lower. Such a brake pipe is indicated in Fig. 2 at 92.
For each sanding unit there is a small reservoir 93 which may, for example, be fed from the brake pipe through a check valve 94 and a flow restricting choke 95, the purpose of the flow restricting choke being to prevent derangement of the braking system by the demand of the sanding system for air. This scheme is merely representative of any local source of sanding air. So far as the present invention is concerned it is. immaterial how the air is supplied.
As indicated in Fig. 2, the remainder of the sanding equipment on the various cars is identical -with that shown in Fig. 1. Similar reference numerals, with the distinguishing letters a and b, are used to distinguish the second and third units from the leading units previously described. While only three units are shown in Fig. 2, and while only the leading wheel of the truck is shown, it will be understood that the sanding apparatus is repeated throughout the entire length of the train, and every braked wheel or at least the leading Wheels of every truck are sanded.
The operation of the device has been explained as the description proceeded, and only a brief recapitulation is needed.
Operation of any of the instrumentalities associated with the sander valve 8 causes energization ofthe sander switch I2 to close the circuit, energizing the windings' 38, 38a, 38h, etc., simultaneously. The effect of this is to deliver air through the jet pipes 5I, Sia, 5Ib, and simultaneously through the clean out pipes 52, 52a, 52h, of the Sanders. The effect is to start the jets into operation and isolate the sand traps from the sand boxes. Then if any nozzle 14, 14a, 14h is obstructed, the immediate development of high pressure will clear the obstructed nozzle. At this and at any nozzle which is not obstructed, rapid delivery of sand to the rail will occur and will continue until the sand in the traphis exhausted unless sooner terminated by sure in the pipe 5| (or ila or Mb), will be disslpated and the corresponding intercepting valve loY will move to its lower position permitting its trap to be recharged with sand.
The invention has been described in considerable detail, but the description is intended to be illustrative and not limiting.
What is claimed is:
1. 'Ihe combination of a sand trap or the like and a sand intercepting valve adapted to seal air tight said valve 'comprising valve elements relatively movable toward and from one another,
at least one of said elements being resilient and affording a distensible pocket into which sand trapped between the valve elements isV forced during closing movement of the valve, to an extent suiiicient to permit tight closure of the valve elements.
2. The combination of a sand trap or the like and a sand intercepting valve, said valve comprising a resilient rubber-like valve seat member .having a distensible 'tubular walled approach passage; means for sustaining said seat while leaving the walls of said approach passage free to expand; and a valve movable toward and from said seat, the distension of the approach passage. when sand is compacted by closing movement of theV valve serving to permit retrogradel movement of the sand and tight closure of the valve.
3. The combination of a sand trap or the like and a sand intercepting valve, said valve comprising a valve seat member; a distensible conduit forming member leading thereto; and a valve movable toward and from said seat, the distensibility oi said conduit member serving to relieve the arching tendency of the sand and thus permit complete closure of the valve.-
4. The combination of a source of sand; a sand trap normally in communication with said source and arranged to receive a charge of sand by gravity ilow therefrom, said trap including a duct through which the trap may discharge sand to a point of use and sand feeding jet means substantially alined with said duct; means for supplying air under pressure to said iet means to discharge sand through said duct; and pressure operated means rendered eilective by the supply of such air to seal the trap from said source.
5. 'Ihe combination of a source of sand; a sand trap normally in communication with said source and arranged to receive a charge of sand by gravity flow therefrom, said trap including a normally inactive duct through which sand may be propelled against the action of gravity to a point of use, and sand propelling jet means substantially alined with said duct; means serving to isolate said trap from said source; and means serving to operate the last named means and substantially simultaneously supply pressure iluid to said jet means to cause discharge of sand from the trap through said duct.
6. 'I'he combination of a sand trap arranged to be operated under substantial pneumatic pressure during the sanding operation, said trap including sand-feeding jet means; means for supplying pressure fluid to said trap and jet means; and a sanding nozzle arranged to-be i'ed by said trap and subject to pressure in the trap, said nozzle being deformable by the pressure used to operate the trap. and the parts being so arranged that the nozzle will be deformedand tend to clear itself at least ii the trap is under operating pressure and ilow vthrough the nozzle is l materiallylimpeded.
7. The combination of a pneumatic sand trap arranged to be operated under substantial in ternal air pressure when tlow therefrom be re` sisted; and a distensible nozzle through which said sand trap discharges, said nozzle being arranged to be distended andy thus clear itself as an incident to the development oi' pressure said trap.
8. 'I'he combination of a train having a plurality of braked wheels; a plurality of pneumatic sand traps, said traps corresponding to diilerent wheels, and each arranged to be operated i d under substantial internal airpressure when ow therefrom is resisted; distensible sanding nozzles corresponding to .the vvarious traps and through which such traps deliver said4 to the wheels, ,said nozzles beingv arranged to be dis-v tended and hence each to clear 'itselfjas .an incident to the development of pressure in a corresponding trap; ,andameans for delivering air under pressure to all said traps simultaneously.
9. The combination of a train having a plurality of braked wheels; a'plurality of pneumatic-sand traps, said traps corresponding to different wheels, and each arranged to be op erated under substantial internal air pressure when ilow therefrom is resisted; ldistensible sanding nozzles corresponding to the various traps and through which such traps deliver sand to the wheels, said nozzles being arranged to be distended and hence each to clear itself as an i sanding nozzle; means for supplyingair under pressure simultaneously to said clean-out con- .nection and to said air nozzle to initiate sanding, and for then terminating the supply of air to the clean-out connection; and pressure operated means operated by pressure of air supplied to the air nozzle and serving to isolate said trap from said source.
11. A sand trap comprising in combination a body having a lower chamber havinga discharge opening and a crest over which sand may vflow to the discharge opening, and an upper chamber having a supply connection and a passage for delivering sand from the upper to the lower chamber in position to be arrested by the crest; connections for supplying clean-out air to both chambers simultaneously; jet means for stirringv sand in the lower chamber for causing it to ow over the crest; jet means for propelling sand through said discharge opening; pressure opererated closing means receive air simultaneously from one connection which is distinct from the clean-out connection, the clean-out connection being of relatively larger flow capacity.
14. The combination defined in claim ll-in which the stirring jet is ldirected across the upper portion of the lower chamber toward the passage from the upper to the lower chamber and in a direction away from the crest, and the propelling jet is directed substantially axially into said discharge opening, both jets being fed by a single connection.
15. I'he combination defined in claim 1i in which the pressure operated supply closing means comprises a valve, one element of which includes a distensible pocket serving to permit retreat of the sand as the valve closes.
16. 'I'he combination of a sand supplying means; a sand-trap-comprising a body having a lower chamber formed with a discharge opening and a crest over which sand may iiow to the discharge opening, and an upper chamber normally in free lcommunication with said supplying means, and having a discharge opening for delivering sand to the lower chamber in position to be arrested by said crest; a large capacity cleanout connection for delivering air to both said chambers simultaneously; two iet nozzles, one for directing stirring air into the lower chamber, and the other for directing a propelling jet through said discharge opening; a pressure operated interceptor for isolating the sand trap from the sand supplying means; a second connection for supplying air under pressure to said iet nozzles and pressure operated interceptor; and means for supplying air simultaneously to said connections and then terminating the supply to the rst-named connection while continuing the supply to the second connection.
17. The combination of a sand supplying means; a sand-trap comprising a body having a lower chamber formed with a discharge opening and a crest over which sand may flow to the discharge opening, and an upper chamber normally in free communication with said supplying means, and having a discharge opening for delivering sand to the lower chamber in position to be arrested by said crest; a clean-out connection for delivering air to both said chambers simultaneously; two :let nozzles. one for directing stirring air into the lower chamber, and the other for directing a propelling jet through said discharge opening; a pressure operated interceptor for isolating the sand trap from the sand supplying means; a second connection for supplying air imder pressure to said jet nozzles and pressure operated interceptor; means for supplying air simultaneously to said connections and then terminating the supply to the iirst-named connection while continuing the supply to the second connection; and a pressure deformable self-clearing nozzle connected with the discharge opening o! said lower chamber and arranged to discharge sand to a point of use.
18. A sanding mechanism comprising in combination a sand trap including a body having a lower chamber provided with a discharge opening and a crest over which sand may iiow to the discharge, and an upper chamber having a supply connection and a passage for delivering sand from the upper to the lower chamber in position to be arrested by the crest; connections for supplying air to both chambers simultaneously, said connections including a relatively large pressure-equalizing passage connecting said chambers; a distensible nozzle through which said trap discharges, said nozzle being arranged to distend and clear itself if subjected to abnormal internal pressure; jet means for feeding sand over said crest through said discharge to said nozzle; means for sealing said supply connection; and means for operating said sealing means, and supplying air under pressure toV said large capacity connections at least during the initial portion of the sanding operation, and for supplying air under pressure to said jet means during the sanding operation.
19. The combination of a sand feeding device and a sand intercepting valve adapted to seal air-tight, said valve comprising a. seat element and a valve element movable relatively toward and from one another, the seat element being resilient and affording a distensible pocket into which sand trapped between the two elements may be forced and the valve element including a resilient bulb distensible upon admission of pres-` sure iiuid thereto to cause closure of said valve element against the seat element.
20. The combination of a source of sand; a sand trap connected to be fed thereby; a sanding nozzle to which said trap delivers sand; a clean-out connection; at least one air nozzle for pneumatically delivering sand from said trap to said sanding nozzle; means for supplying air under pressure simultaneously to said clean-out connection and to said air nozzle to initiate sanding, and for then terminating the supply of air to the clean-out connection; and pressure operated means serving to isolate said trap from said source and arranged to be controlled by said airsupplying means.
2i. The combination of sand supplying means; a sand trap comprising a body having a chamber arranged to be fed by said supplying means; and having a discharge opening and a crest over which sand may be caused to ilow to the discharge opening; a clean-out connection for delivering air under pressure to said chamber; two iet nozzles, one for directing air to propel sand over said crest and the other for directing a propeiling jet through said discharge opening; a second connection for directing air under pressure to said nozzles; a pressure-operated interceptor arranged to be actuated by pressure developed in one of said connections and serving when active to isolate said chamber from said sand supplying means; valve means operable to supply air under pressure simultaneously to both said connections and then to terminate the supply to the firstv while continuing the supply to the second; and a pressure-deformable self-clearing nozzle connected with said discharge opening and arranged to discharge sand to the point f use.
CHARLES A. CAMPBEIL. LEWIS A. SAFFORD.