US1773753A - Safety appliance for locomotives - Google Patents

Description

Aug. 26, 1930. J. G. ROBINSON SAFETY APPLIANCE FOR LOCOMOTIVES 2 Sheeis-Sheet 1 Filed Sept. 30, 1929 ii. u E:

9 J. G. ROBINSON: 1,773,753

SAFETY APPLIANCE FOR LOCOMOTIVES File Sept. 50, 1929 2 Sheets-Sheet 2 ml I I m k 1 i-n' El 5559: N

Patented Aug. 26, 1330 times JAY G. ROBINSON, or CHICAGO, ILLINOIS saFE'rY APPLIANCE FOR LOCOMOTIVES Application filed September The purpose of my invention is to provide means whereby the rupture of the shell or tubes'of a steam locomotive boiler with re-. sulting discharge of steam into the fire-box,

an occurrence generally known as a blowout, will actuate mechanism to automatically apply the brake's and to also close the fire-box door in the event that it is open or cracked at the time. In my pending appliic cations for patent Ser. Nos. 380,117 and 381,763, filed July 22, 1929and July 29, 1929 respectively, I describe means whereby the pressure in the fire-box is utilized to cause the fire-box doors to close if in open or cracked position at the time of a blow-out. The struc ture of this part of the mechanism and of the pneumatically operated "fire-box door shown and described herein is similar to that shown in my first applications and isthere described 29 more in detail than herein. In this application the more detailed description relates to the part of the mechanismwhich act'uates the air-brakes. 1

In the drawings,

Figure 1 is an elevation partly in section, of my improved fire-box door, and related mechanism.

Figure 2 is a fragmentary plan view partly in section showing certain parts on an enlarged scale. i t

Figure 3 is an enlarged elevation partly in section of certain details of the power cylinder. I 7

Figure 4 is a sectional View of the airbrake controlling valve.

Figure 5 is a plan view partly in section of a modified form of the air-brake control valve.

. The fire- box doors 1,2 are pivoted-at 3,4

to the door ring 5 which is fixed tothe boiler head and surrounds the fire-dooropening. The doors move ina plane parallel tothe boilerhead and meet on the. substantially horizontal line 6. The doorsareactuated by theplunger rod 7 of the difierential cylinder 8. The rod 7 is pivoted at its lower end to and intermediate the ends of the lever'9 at 10. At itsupper and lower ends respectively the lever 9 is pivoted at 11 and 12'to'levers 13 and 14 which latter are pivoted to the door 30,192 9 Serial No. 39 23."

ring 5 at 15 and 16 respectively. Levers 13 and 14 are connected to doors 1 and 2 by links 17 and18, which links are pivoted to the doors at 19- and 20' respectively and to levers 13 and 14 at 21 and 22 respectively. The free end of lever 14 is prolonged beyond pivot 22 and carries a handle at 23. Fixed to the plunger rod 7 are the small and large piston heads 24, 25 fitted to the small and large bores of the difierential cylinder 8. By means of a treadle 40 and valve 41 the engineman controls admission and exhaust; of air under pressure to and from the chamber 26 above the large pistonhead 25, connection with this chamber being established through duct 27 which communicates with port 28 wherein is an inwardly opening check valve 29. v

Communicating with the lower part of the large bore 30 of the cylinder is a port 31 (Fig ure 3) which connects with a duct 35 in which are mounted the pet-cock 32 and inwardly opening check valve 33. At its outer end 36 duct 35 communicates with a pipe through which it receives air under ressure at all times from the main reservoirof the brake system and pet-cock 32 normally occupies the position. shown in Figure '3, being moved therefrom only for the purpose hereinafter described. I

The means for utilizing the pressure caused by &'bl0W-O1lt to actuate the door-closing and brake-applying mechanism comprises an open-ended cylindrical sleeve 42 extending through and welded to the edges of openings in the boiler plates 43, 44. Slidably fitted in the sleeve 42 is a plunger 45 provided with a projecting stem 46. The movement of the plunger may be limited by stops 47, 48,the plunger being provided with longitudinal grooves 49, 50. In'assemblage the" grooves 49, 5O permitthe plunger 45 to be inserted in the sleeve 42 after whi'ch'the plunger may be given a partial rotation to carry the grooves out of registry with the stops.

" It will be'apparentthat the interior surface ofthe plunger 45 is exposed to the conditions of pressurein the fire-box and the outer suriaceto atmospheric pressure. The relatively high pressure in the fire-box caused by a blowout will move the plunger outwardly and thereby actuate the door-closing and brakeapplying mechanism hereinafter described.

s above stated air at reservoir pressure, say about ninety pounds per square inch, is constantly supplied through the opening 36 to the space 30 between the'large and small plungers, this condition being altered only for the purpose of cracking the doors, that is, setting them at partially or wholly open position. Normally the reservoir pressure in the space 30 causes the plungers 25, 24 to occupy their uppermost position as shown in Figure 1, the valve 41 normally permitting escape of air from the space 26 above the largepiston 25 through the opening 27 The movement of the pistons to the upper position referred to results from the greater diameter of the plunger 25 as compared with the plunger 24. To open the doors the engineman actuates the valve 41 by pressing the treadle 40, thus permitting air at reservoir pressure to enter the opening 27 and to flow into the space above the large plunger 25. The preponderance of downward pressure carries the plungers downward and the plungerrod 7 which is connected through link 51 with the lever 9 imparts downward movement thereto. Through the pivotal connections 11 and 12 of the lever 9 with the levers l3 and 14 the doors are moved to open position and upon release of the treadle 40 the valve 41 returns to its normal position wherein the opening 27 into the space above the large piston is connected with the atmospherethrough the valve 41 with the effect of causing theplunger to rise and the doors to close. a I

In order to provide for cracking the doors the port 31 is provided with a pet-cock32, the pet-cock is provided with an arm 52 pivotally connected with a rod 53 which extends horizontally across and abovethe fire door opening to a position convenient to firemen and is provided with a handle 54. [In order to crack the doors the rod 54 is pushed to the right as viewed in Figure 1. This has the eiiect of moving the three-way pet-cock 32 fromthe position shown in Figure 3 to a position wherein the port 35 is blocked and the port 81 is connected with the atmosphere through the port 55. This'has the effect of reducing the pressure between the pistonsto thatoffthe atmosphereand as there isno pressure in the space 26, above the large piston except when the foot treadle 40 is depressed, the movementot the differential plungers is now unrestrained. It will be understood that the lower; end ofv thexditler ential cylinder 8 is open, to, the atmosphere. Having moved the pet-cock ,to the position described, the engineman opens the doors, by manual power to the position desired which maybedonei either by using the handle 23 orthehandle .56.. Theidoors will remain in the position into which they are so moved inasmuch as through the lever system described they counterbalance each other. The horizontal rod 53 extends beyond the arm 52 of the pet-cock to a pivotal connection 57 with one arm of a bell crank 58 which is pivoted at 59 to a bracket upon the cylinder structure or other stationary support. A pin 60 at the extremity of the other arm of the bell crank engages a slot 61 at the outer end of the stem 46 of the plunger 45, the parts being so proportioned preferably that movement of the arm 53 to the right imparts a slight inward movement to the plunger and its movement to the left a slight outward movement thereto. This slight movement imparted to the plunger 45 is merely for the purpose of insuring its free movement by dislodging any dust or other matter that might accumulate in the sleeve 42.

Assuming that'the arm 53 has been moved to the right, that is, to the dotted line position shown in Figure 2, and that the doors have been cracked, it will be apparent that the occurrence of a blow-out will cause such pressure in the interior of the fire-box as to force the plunger 45 outwardly thereby through the engagement of the inner end of the slot 61 with the pin lrestoring the bell crank 58 tothesolid line position shownin Figure 2, and also restoring the pet-cock 32 to the position shown in Figure 3. This has the effect of admitting air under reservoir pressure to the space 30 between the plungers 25, 24, and instantly closing the fire-box doors thereby preventing eruption of steam, coal and flames into the cab. This part of the mechanism is substantially as described in my prior applications above referred to.

The plunger rod 46, as shown in Figure 2, is provided with an upwardly projectinglug 62 which lies in line with the arm '63 of a bell crank lever 64 which is pivoted to a bracket 65 fixed to the boiler head or other stationary support. The other arm 66 of the bell crank lever is pivoted to a rod 67 which ,at its opposite end is pivoted at (58 to an arm 69 extending from a valve 7 0 which controls the passage of .airthrough a pipe 71 which is in communicationwith the brake pipe or trainpipe of the air brake; system. The connection of this pipe may be made in any manner which is most convenient in;1the particular arrangement of the parts upon the boiler head and in the brake system. As illustrated the engineers brake .valve may beconsidered as beingyconnected to the end 72 of the pipe 71 and theend 73 thereof as extending to the part of the brakepipe which extends to the locomotive tender. In Figure 4 I show a sectional view of the valvefOhccu? pying its normal,p'ositionwherein free passage of air is permitted through the pipe 71. This, is the position occupied by valve at all times except when moved therefromlby a blow-out, the arm 63 of hell crank 64 being so disposed with relation to lug 62 that the v ignated 66, and of moving the arm of valve 70 from the position 69 to the dotted line position designated 69'. This has the effect of moving the valve from the position shown in Figure 4 to a position in which the pipe 71 is blocked and the part of the pipe to the left of the valve is exhausted to atmosphere through the opening 7% duction of pressure in the brake pipe has the effect of setting the brakes in the usual way.

The precise arrangement of the connection between the plunger 45 and the valve for settin the brakes will, of course, be dependent upon the arrangement of the appliances upon the boiler head. the air pipe extending from the engineefs valve to the train pipe as provided with a section adjacent to the stem 46 of the plunger 45. With this arrangement the arm 69 oi the valve 70 engages a slot 75 in the rod 46 the ends of the slot being indicated by the dotted lines 77, 78. The operation with the parts so arranged is the same as above described.

From the foregoing it will be apparent that the outward movement of the plunger 45 caused by a blow-out will have the effect of setting the air brakes, and in the event that the doors are cracked at the time, instantly closing them. This arrangement afiords protection to the enginemen 'by'closing the fire-box doors and thereby at the earliest possible moment stopping the egress of steam, hot gases and coal from the fire-box into the cab, and also affords protection to the entire train by setting the brakes at a time when the enginemen might be unable to do so. Incapacity of the enginemen at such a juncture has in some instances resulted in a train running wild and coming to a stop only when wrecked. It will be apparent that my invention may be used independently for either of the purposes above mentioned, or that it may be connected to serve both purposes as herein illustrated and described.

It will also be apparent that the operative connection between the plunger 45 and the valve in the brake line may be arranged in many different ways, and that if desirable or convenient an operative connection may be established between the plunger and the ensponsive to super-atmospheric pressure in the fire-box, and means controlling the opera- The resulting retion of said locomotive comprising parts having operative connection with said movable element. I

2. In a locomotive, a movable member responsive to super-atmospheric pressure in the fire-box, an air brake system, and an operative connection between said movable memher and said air brake system.

8. In a locomotive, a movable element responsive to super-atmospheric pressure in the fire-box, an air brake system comprising an operating valve and an operative connection between said movable element and said valve.

4; In a locomotive, a movable elementresponsive to super-atmospheric pressure in J AY G. ROBINSON,

September, 1929.

In Figure 5 I have shown

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