US2523696A

US2523696A - Hydraulic locking cylinder for locomotive reversing gear

Info

Publication number: US2523696A
Application number: US607962A
Authority: US
Inventors: Hadfield James
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-10-07
Filing date: 1945-07-31
Publication date: 1950-09-26
Anticipated expiration: 1967-09-26

Description

Sept. 26, 1950 J. HADFIELD HYDRAULIC LOCKING CYLINDER FOR LOCOMOTIVE REVERSING GEARS 3 Sheets-Sheet 1 Filed July 31, 1945 Ins en'To/t J. HADFIELD HYDRAULIC LOCKING CYLINDER FOR Sept. 26,1950

LOCOMOTIVE REVERSING GEARS 3 Sheets-Sheet 2 Filed July 31. 1945' iiiiljk- 1 v VIIvrlldltrllllllrlllillfr Mu s a n 3 e 4 2 m 3 KW S. H v a \,,,,,,./A I? RI: m n 3 \b/ L I\ W MV/// I, l W Li 5 Fs Rm 7 v "\h A IG mum m m FG 0mm m "1mm JCH um U0 mm m Patented Sept. 26, 1950 HYDRAULIC LOCKING CYLINDER FOR LOCOMOTIVE REVERSING GEAR James Hadfield, Romiley, England Application July 31, 1945, Serial No. 607,962 In Great Britain October 7, 1944 This invention relates to reversing gear for steam locomotives of all types where the engine is reversed by means of a power operated reversing gear comprising a power cylinder operated by steam, compressed air or other suitable medium and a hydraulic cylinder for the purpose of locking the gear in any desired position.

Apparatus of this type as hitherto constructed has suffered from two main and complementary defects. The hydraulic locking cylinders have been difficult to fill completely so as to ensure that all air is evacuated in the filling process and, moreover, even when initially filled completely, difficulties have been experienced in maintaining the hydraulic cylinders full and free from air since leakage is, to some extent, inevitable and in the normal arrangements at present known any liquid which leaks out is replaced by air. The result is that a positive lock is not provided and thegear creeps.

The object of the present invention is to remedy these defects so as to ensure positive locking for any position of the reversing gear and the primary feature of the invention is the provision in a power operated reversing gear, of a pump automatically operating to replace any liquid which leaks from the hydraulic cylinder, whereby the cylinder having once been filled is maintained full under all conditions.

A further complementary feature of the invention is the method of initially filling the hydraulic lockin cylinder according to which the filling operation is effected by means of a pump and takes place from the bottom of the cylinder so that the air in the cylinder is discharged as the liquid level in the cylinder rises. Thus, if the filling from the bottom ofthe cylinder is continued until there is an overflow of the oil or other liquid from vents at the top, a completely filled cylinder free from air results.

The essential factors necessary for the practical success of the invention may be stated as the provision of means whereby the hydraulic locking cylinder can be expeditiously and completely filled, means whereby the hydraulic system will be instantly and automatically replenished should any liquid escape therefrom, and means whereby the two ends of the hydraulic cylinder can be'interconnected one with the other, or completely isolated one from the other.

The invention consists broadly of reversing gear for steam locomotives comprising a power cylinder or unit for efiecting the movements 2 Claims. (01. 121-40),

, 2 of the gear under'control from the engine cab, and a hydraulic locking cylinder for locking the gear in its set portions, wherein a supply of liquid under pressure is provided and conducted to the hydraulic locking cylinder on both sides of its piston, whereby on the occurrence of leakage from the hydraulic lockin cylinder such liquid as leaks out is automatically replaced from said supply.

In order that the invention may be clearly understood and carried into practice reference is hereby made to the accompanying drawings, wherein:

Figure lis a side elevational View showing the general arrangement of the invention applied to a locomotive reversing gear of known general character;

Figure 2 is a section on the line 2--2 of Figure 1;

Figure 3 is a sectional side elevation of the pump shown at the right hand side of Figure 1;

Figure 4c is a plan and Figure 5 is an end view of Figure 3;

Figure 6 is a, sectional view of the hydraulic locking cylinder showing one form of the hydraulic control valve which may be employed;

Figure '7 is a sectional end view thereof; and

Figures 8 and 9 are views similar to Figures 6 and 7 illustrating an alternative form of hydraulic control valve.

Referring to these drawings Figure 1 shows the general arrangement of a power operated reversing gear which consists of a power operated unit A; hydraulic locking cylinder B and control lever C connected at D to 'an operating lever E in the drivers cab. The control lever C is also connected at F: through link G to the crosshead H on the reverser piston rod and at J by means of links connected to levers on the powervalve K and hydraulic valve L respectively. There are, oicourse, other known'arrangements of power operated reversing gears having hydraulic cylinders but the function of the hydraulic locking cylinder in all arrangements is to lock the gear in any desired position.

In Figures 3, 4 and 5 theautomatic pump which is the characterisation of the present invention and is indicated by the letter P in Figure 1 is shown in detail. I

This automatic pump consists of a plunger M loaded by a spring N and capable of operation by a hand lever O.

On operating the hand lever 0, liquid is drawn from the reservoir P through the non-return valve Q into the pump chamber R.

The plunger M under load from the spring N exerts a pressure on the liquid which is forced through the non-return valve S and then through the pipe T and the non-return valves U (Figure 6) to the two ends of the hydraulic cylinder B.

The non-return valves U are shown in Figure 6 as being of the ball type but it will be understood that any other form of non-return valve may be used.

An indicator may be provided on the pump casing suitably marked to show whether the pump plunger M is in the fully charged position or otherwise. The pump unit may be located in the drivers cab or in any other convenient position.

For the initial filling of the hydraulic cylinder the air vent plugs V (Fig. 6) are first removed and the hydraulic control valve is placed in the open" position. The pump reservoir P is filled with a suitable liquid (usually oil or water) and the pump is operated until the liquid entering the cylinder B by wa of the pipe T and branch pipes T and T flows through the vent holes on the top of the hydraulic cylinder. The pump reservoir must be replenished from time to time as may be necessary until this preliminary filling operation is completed.

The vent plugs V are then replaced and the pump reservoir P is refilled and the charging lever moved into the fully charged position.

Should any leakage occur thereafter through the glands of the piston rod of the hydraulic cylinder or elsewhere, liquid, under pressure exerted by the pump plunger M acting under the load of the spring N, will flow into the hydraulic cylinder thus replenishing the cylinder with liquid and preventing the ingress of air which would otherwise take place.

The only attention required by the apparatus under running conditions is to maintain the level of the liquid in the reservoir P and to move occasionally the hand lever O to the fully charged position.

In order to permit of the interconnection or isolation of the ends of the hydraulic cylinder 13 the hydraulic cylinder is provided with an improved type of hydraulic control valve as shown in Figure 6. This valve consists of two spring loaded poppet valves W which are operated by a cam X through intermediate rockers Y, this arrangement ensuring that the two ends of the hydrau'l'ic cylinder are positively isolated when the cam X is in the shut position. It will be obvious that the higher the pressure occurring in the hydraulic cylinder by the action of the locomotive valve gear the more tightly closed become the valves W, thus eliminating all tendency for the reversing gear to creep.

An alternative type of hydraulic control valve is shown in Figures 8 and 9. This consists of a cylindrical piston valve Z sliding in a liner AA and capable of being operated by the lever BB.

Suitable ports are provided in the valve and liner, so arranged that displacement of the valve in either direction away from the central closed position will permit the liquid to flow from one end of the hydraulic cylinder to the other thus permitting the reversing gear to move until the hydraulic valve is returned to the central or closed position.

Provision will preferably be made for adjusting the operating speed of the reverser by means,

for example, of a throttling plug indicated at CC and the function of which is to regulate the rate of flow of liquid passing from one side of the hydraulic piston to the other. Adjustment is made by modifying the dimensions of that part of the throttling plug which projects into the port of the hydraulic cylinder.

I claim:

1. Reversing gear for steam locomotives comprising a power unit having a moving member for imparting the required movement to the gear, a horizontally positioned hydraulic locking cylinder, a piston slidable in said locking cylinder and coupled to the moving member of the power unit, a valve housing atop said cylinder, valve means in said housing, a passageway interconnecting opposite ends of said cylinder through said valve means, said valve means comprising a pair of oppositely disposed aligned valve seats, a pair of valve members adapted to engage the outer faces of said valve seats and close off said passageway, springs normally holding said valve members in engagement with said valve seats, a pair of rocking levers disposed between said valve seats and each engaging one of said valve members, and a cam disposed between said rocking levers for engaging them and moving them apart, whereby to disengage the valve members from the valve seats to open said passageway, closable vent means adjacent the top said valve housing, a hydraulic fluid inlet adjacent the bottom of each end of said cylinder, means for supplying hydraulic fluid to said inlets, and means maintaining said fluid under pressure.

2. Reversing gear for steam locomotives comprising a power unit having a movable member for imparting the required movement to the gear, a hydraulic locking cylinder, a piston slidable within said cylinder and coupled to the movable member of the power unit, a hydraulic fluid inlet to each end of said cylinder, means supplying hydraulic fluid to said inlets, means maintaining said fluid under pressure, means forming a passageway interconnecting opposite ends of said cylinder, valve means in said passageway controlling the flow of fluid therethrough, said valve means being biased to closed position by means including the pressure exerted on said fluid by said pressure maintaining means, and means actuated simultaneously with the motion of said movable member for opening said valve means to thereby place both ends of said locking cylinder in communication with one another.

JAMES HADFIELD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 708,332 Ennor Sept. 2, 1902 1,094,243 Pilling Apr. 21, 1914 1,248,357 McEntire Nov. 27, 1917 1,307,281 Wallace June 17, 1919 1,954,417 Lentz Apr. 10, 1934 2,397,270 Kelly Mar. 26, 1946 FOREIGN PATENTS Number Country Date 8,274 Great Britain of 1915 216,596 Great Britain June 5, 1924