AUTOMATIC LOCKING MECHANISM FOR AIR BRAKE HOSE COUPLING MEMBERS

Abstract: An air pressure actuated stop assembly (50) is disposed in at least one of first and second rotatably engaging housings of a coupling assembly (10), the housings (14) being affixed to ends of respective associated hoses (70) to complete an air passageway (24) therebetween when coupled. Each housing (14) has a portion with an exterior surface adjacent an interior surface of a complementary portion of the other housing (14) and slidable therealong during coupling and uncoupling of the assembly (10). The stop assembly (50) includes a spring biased pin (52) that moves when actuated by air pressure in the air brake hose (70) to a position to obstruct the path traveled by the portion of the opposite housing (14) in a direction uncoupling the two housings (14) thereby preventing uncoupling of the housings (14) when the air brake system is pressurized. The pin (52) is automatically retracted when the air pressure is released thus permitting the housings (14) to be uncoupled.

Description: AUTOMATIC LOCKING MECHANISM FOR AIR BRAKE HOSE COUPLING MEMBERS This invention relates to air hose coupling members for detachably connecting the ends of air brake hoses for trucks or railroad cars to form an air-tight connection. More particularly, the invention relates to a locking mechanism for a pneumatic braking system for preventing accidental rotational separation of joined coupling members. Pneumatic brake systems having flexible air hoses are typically used between adjacent railroad cars and with certain types of trucks. A coupling member is attached to each end of a flexible air hose for detachably connecting the air hose sections together. The sections extend from the braking system of each car when the individual railroad cars are joined to form a unit train. These coupling members, which are joined together by a rotational downward motion, engage mating flanges and lips that extend from the housings of the coupling member. In most instances the coupling members are suspended between the cars and hang a short distance above the railroad tracks. Occasionally, the coupling members become uncoupled prematurely when the hoses are subjected to a sudden upward movement caused by the motion of the railroad cars. This accidental separation of the coupling members between two sections of air hose during the operation of the train causes the emergency brakes to be applied resulting in delay and inconvenience and presenting potential safety problems. It is desirable, therefore, to have an anti- disconnect device that prevents inadvertent rotational disengagement. It is further desirable, however, that the anti-disconnect device not prevent disengagement when a longitudinal force is applied along the length of the hoses such as occurs when two cars are uncoupled. U.S. Patents 3,892,431, 3,879,066 and 5,388,864 disclose examples of known locking devices for air brake hoses. The device in the "431 patent requires that a spring loaded outwardly extending member be manually depressed before the coupling housings may be engaged or separated by rotating the coupling housings with respect to each other. The "066 patent discloses a locking device that is gravity activated. The "864 patent discloses a locking device that is manually operated by railroad employees when they are engaging the air hoses between the cars. In the standard pneumatic braking system, the air pressure in the system maintains the brakes in an "off" position. Activation of the braking system is caused by a drop in the pressure. A locking system to prevent accidental disengagement is limited to one that is independent of the amount of pressure in the pneumatic brake lines or ones that must work within the normal operating range of the brake system, usually 50 to 90 p.s.i.. The braking systems of the prior art are manually operated. In an electro-pneumatic operated brake system, on the other hand, the air pressure in the hoses is held constant. The brakes are activated by electrical signals rather than by fluctuations in the pressure in the air hoses. Thus, it is desirable for the electro-pneumatic system to have a locking system that is automatically engaged when the system is pressurized. The present invention is directed to an automatic locking mechanism that alleviates the problems associated with the prior art. In accordance with the invention, the locking mechanism for an air brake hose assembly is an air pressure actuated stop assembly secured in at least one of the housings of the coupling members. The coupling member assembly includes first and second rotatably engagable housings that are affixed to ends of respective associated hoses to 1 'complete an air passageway therebetween when coupled. Each of the housings has a portion with an exterior surface adjacent an interior surface of a complementary portion of the other housing and slidable therealong during coupling and uncoupling of the housings. The air pressure actuated stop assembly is disposed in this portion of one of the housings. When actuated by air pressure in the air brake hose, the stop assembly is movable to a position to obstruct the path traveled by the portion of the opposite housing in a direction uncoupling the two housings thereby preventing uncoupling of the housings when the air brake system is pressurized. In accordance with the invention, at least one of the coupling housings includes a bore extending from communication with an exterior surface thereof and into communication with an air passageway of the coupling member. The bore has a first portion dimensioned to slidingly receive a stop assembly, a second portion having a diameter smaller than the first portion, and a tapered transition portion extending therebetween. In a preferred embodiment, the releasabie stop assembly includes a pin, a spring and a retaining bushing. The pin includes a head or flange portion at one end thereof dimensioned to be slidingly received into and be movable along the first bore portion with a relatively air tight fit. A shaft extends outwardly from the flange surface and is dimensioned to receive the spring. The pin and spring are secured in the first passageway portion by a retaining bushing dimensioned to be press fit in the first bore portion. The pin remains in the bore and is biased inwardly to withdraw the shaft end within the bore when the air hose is not under pressure. Upon coupling the housings together and charging the brake system with air, the pressurized air enters the second bore portion, passes into the transition portion and is distributed across the stop surface of the flange and the resultant force moves the pin outwardly against spring bias such that the pin extends beyond the housing and prevents the coupled housings from being rotationally uncoupled. The pin remains in the extended position as long as the brake system is pressurized above some minimum amount, such as for example, 50 p.s.i. Upon releasing the pressure in the air hoses, the spring biases the shaft end inwardly, thereby permitting the coupled housings to be rotationally separated. In a preferred embodiment, the stop assembly is located on the coupling member or gladhand at a selected location that permits the coupling member or gladhands to rotate within a desired range while preventing the gladhands from rotating a sufficient distance to become disconnected. The stop assembly, furthermore, is located such that it will not interfere with disengagement of the hoses by pulling in n axial direction when two cars are disconnected from each other. The present invention has the advantage of providing for axial disengagement of two interlocking coupling members while simultaneous preventing rotational disengagement. The present invention further has the advantage of being operated automatically when the pressure line is charged thus eliminating manual engagement of the pin as a locking device. This feature is particularly important for electro-pneumatic systems that have electrical connectors secured to or as part of the coupling housings, such as the system disclosed in U.S. Patent Application Serial No. 08/708,435.. The present invention provides an automatic locking system that eliminates the problem of someone inadvertently failing to engage the system and also minimizes the time required to manipulate the hose coupling members, known as gladhands, when engaging the system between the cars. The locking mechanism of the present invention furthermore is cost effective to install and may be provided on the coupling member with a minimum amount of materials and labor. Embodiments of the invention will now be described by way of example with reference to the following drawings in which: FIGURE 1 is an isometric view of a hose coupling member made in accordance with the invention attached to an air hose and having the air pressure actuated stop assembly exploded therefrom. FIGURE 2 is an isometric view of the coupling member of Figure 1 with the stop assembly positioned in the coupler housing and in its extended or stop position. FIGURE 3 is an enlarged fragmentary view of the coupling housing of Figure 1 with the outer structure broken away to show the structure of the bore for receiving the stop assembly. FIGURE 4 is a view similar to that of Figure 2 with the members of the air pressure actuated stop assembly disposed within the housing bore in its unextended position when the braking system is not under pressure. FIGURE 5 is a view similar to that of Figure 4 illustrating the position of the stop assembly when the brake system is under pressure. FIGURE 6 is an isometric view of two coupling members joined together prior to the brake system being charged with air. FIGURE 7 is a view similar to that of Figure 6 showing the position of the air pressure actuated stop assemblies after the brake system has been charged with air. FIGURE 8 is an enlarged fragmentary view of the an alternative embodiment of the stop assembly disposed within the housing bore in its unextended position when the braking system is not under pressure. FIGURE 9 is a view similar to that of Figure 8 illustrating the position of the stop assembly of Figure 8 when the brake system is under pressure. FIGURE 10 is a view similar to that of Figure 8 illustrating a further alternative embodiment of the invention in its unextended position when the braking system is not under pressure. FIGURE 11 is a view similar to that of Figure 9 illustrating the position of the stop assembly of Figure 10 when the brake system is under pressure. FIGURE 12 is a view similar to that of Figure 8 illustrating another embodiment of stop assembly of the present invention. Referring now to Figures i and 2, coupler assembly 10 includes a coupling member 12 mounted to an air hose 70 with clamp 72. Each coupling member 12 includes a housing 14 having an arcuate flange 16 with interlockable grooves and lips 18 and stop surfaces 20 and 22. The housing 14 of coupling member 12 or gladhand, as known in the art, is matable with a like member by rotatably engaging the two coupling members 12 and interlocking the cooperating grooves and lips. The gladhands pivot with respect to one another when coupled so that when a train travels around a curve the rotatable coupling member compensates for compressive forces in the hoses 70. The stop surfaces 20 and 22 engage complementary surfaces of the mating housing 14 to prevent excessive rotation of the two housings 14 with respect to each other when the housings 14 are rotated in the first direction to couple the gladhands together, as shown in Figures 6 and 7. Coupling housing 14 also includes a bore 30 as shown in Figures 3, 4 and 5 dimensioned to receive an air pressure actuated stop assembly 50 including a pin 52, a return spring 62, and a retaining bushing 64. As best seen in Figure 3, bore 30 is in communication with the outer surface 36 of housing 14 and in communication with air passageway 24 of the coupling 12. Bore 30 includes first portion 32 dimensioned to receive pin 52, a second portion 34 having a smaller diameter in communication with air passageway 24 and a tapered intermediate portion 33 that extends from the inner end of fche first portion 32 to the second portion 34. First portion 32 includes a stop surface 38 adjacent tapered transition portion 33. Pin 52 includes a head or enlarged flange portion 54 at the inner end having a first stop surface 56 which engages the first bore portion stop surface 38 and a second stop surface 58 on the opposed flange surface adapted to receive an end of the spring 62. Pin shaft 60 extends from flange stop surface 58 to an outer end and is dimensioned to receive the spring member 62 such that the spring rests against the stop surface 58 at the inner end thereof. The pin and spring are received in the first bore portion 32 and secured therein by the retaining bushing 64, which is secured in the bore 30 in an interference fit. The flange portion i:S dimensioned to be slidingly received into and be movable along the first bore portion 32 in a relatively air-tight fit. Figure 4 shows the air pressure activated stop assembly 50 disposed in the bore 30 with the pin 52 retracted and spring 62 extended within the first bore portion 32 when the system is not under pressure. Figure 5 illustrates the position of the stop assembly 50 when the lines have been pressurized. As can be seen from Figure 5, as the pressurized air passes through passageway 24, shown representatively by an arrow, some of the air enters second bore portion 34, and engages the entire rear stop surface 56 of the flange 54. Flange 54 is forced outwardly against the spring and retaining bushing 64 until the spring 62 is compressed between the flange 54 and the bushing 64 and shaft 60r.of pin 52 is moved to a position to obstruct the path traveled by a portion of the opposite housing in a direction uncoupling the two housings 14. Figures 6 and 7 illustrate a mated coupling member or gladhand arrangement with both of the coupling members 12 having the air pressure actuated stop assembly 50 of the present invention with Figure 6 showing the assembly prior to charging the pneumatic brake lines and Figure 7 after the pneumatic brake lines have been charged. As can be seen in Figures 6 and 7, each coupling housing 14 includes a portion having an exterior surface 15 adjacent an interior surface 17 of the other housing 14, the respective surfaces being slidably movable along a semicircular path during coupling and uncoupling. As can best be seen in Figure 7, the stop assembly 50, when activated, moves to a position to obstruct movement of inner surface 17 along exterior surface 15. When end surface 26 engages outwardly extending pin shaft 60, further movement in the same direction is ceased thereby preventing uncoupling of housings 14. The air pressure generally required for the electro-pneumatic braking system is about 90 p.s.i. with the dimensions of the bore and flange of the pin being adapted to activate the system at a pressure of at least 50 p.s.i. Figures 8 and 9 show an alternative embodiment 150 of the stop assembly that include the addition of an elastomeric sleeve 63 that functions as an air seal at the forward end of the bore 30 proximate bushing 64 to assure there are no air leaks at the air actuated stop assembly. Figures 10 and ll show a further alternative embodiment 250 of the stop assembly that is a self contained unit that may be inserted into bore 130 of a gladhand. Embodiment 250 includes a retaining bushing 164, an elastomeric seal 163, a spring 62 and pin 52, all of which are contained in a sleeve 80 dimensioned to be pressfit or otherwise secured within bore 130 in a gladhand. Sleeve 80 includes aperture 82 at the inner end thereof that communicates with the air passageway 24, such that, upon pressurizing the air brake system, pressurized air can flow into the sleeve 80 and activate the stop assembly 250 in the manner previously described. Figure 12 shows another alternative embodiment 350 of the stop assembly in which spring 162 is disposed around the outside of seal 263. Embodiment 350 is shown as a self contained unit, however, it is to be understood that the spring 62 may be disposed around seal 63 in the embodiment of Figures 8 and 9. It is to be understood that only one of the gladhands needs to have the locking mechanism in an accordance with the present invention to prevent inadvertent disconnecting of the gladhands after the lines have been charged. The gladhand having the locking structure will mate with all undamaged standard gladhands currently in use by the railroad industry, whether they have a mechanically operated lock or no lock. As can be understood from the foregoing description, the air pressure actuated stop assembly can be readily incorporated into existing gladhand designs with minimal manufacturing changes. If it becomes necessary to disengage the gladhands when the pneumatic braking system is charged, the pin 62 of the stop assembly 50 can be manually pushed into the housing bore 30 and the air hoses 70 can then be manually separated. The air pressure actuated stop assembly 50 of the present invention eliminates the manual labor, the time for engaging a manual lock, and problems associated with manually operated devices when coupling the air hoses 70. Additionally, a manual locking feature may be on the side of the gladhand that is facing away from the employee and be obscured from sight by the structure of the gladhand itself and, thus, may not be engaged by the employee. Since the electro-pneumatic braking system is pressurized at all times while a train is in service, the pin 52 will remain extended at all times, unlike in a conventional air brake system where the pressure varies between off and full pressure, which could allow a pin to retract and extend several times during a trip. This feature is particularly important for electro- pneumatic systems that have electrical connectors secured to or is part of the coupling housings, such as the system disclosed in U.S. Patent Application Serial No. 08/708,435. In a conventional air brake system, on the other hand, if the pressure is sufficiently reduced, the pin would retract thus possibly allowing the coupling members 12 to inadvertently separate.

Claims: WE CLAIM; 1. A locking mechanism for an air brake hose coupling (10) having first and second rotatably engaging housings (14) that are affixed to ends of respective associated hoses (70) to complete an air passageway (24) therebetween when coupled, each housing (14) including a portion having a first surface adjacent a second surface of a complementary portion of the other housing (14) and slidable therealong during coupling and uncoupling of the housings, at least one of the housings (14) including a stop assembly (50) having a having a spring biased pin (52) disposed in a bore (30) of the housing (14) along one of the first and second surfaces, the mechanism being characterized in that: the bore (30) is in communication with the air passageway (24) , and the pin (52) is spring biased away from the one of the first and second surfaces and is movable to an extended position protruding from the one of the first and second surfaces when actuated by air pressure in the air brake hose (70) to a position to obstruct the path traveled by the portion of the opposite housing in a direction uncoupling the two housings (14) thereby preventing uncoupling of the housings (14) when the air brake system is pressurized; whereby the spring biased pin (52) of the air pressure actuated stop assembly automatically moves to a release position when the air brake system is no longer pressurized. 2. The locking mechanism of claim 1 wherein the stop assembly (50) is a self contained unit adapted to be secured in the bore (30) of the housing (14) , the unit including an outer sleeve (80) having the spring biased pin (52) disposed therein, whereby upon disposing the unit in the bore (30), an opening (82) in the sleeve is in communication with the air passageway (24) , such that the pin (52) moves to the extended position when actuated by the air pressure. 3. The locking mechanism of claim 1 or 2 wherein the bore (30) includes a first portion (32) dimensioned to slidingly receive the stop assembly (5<*) , and a second portion (34) having a diameter smaller than the first portion (32) extending from an innermost end of the first portion (32) to the air passageway (24) . 4. The locking mechanism of claim 1, 2 or 3 wherein the stop assembly (50) further includes a retaining bushing (64) to secure the assembly (50) in the bore (30) . 5. The locking mechanism of either of claim 3 or 4 wherein the stop assembly (50) further includes an air seal disposed in the bore (30) proximate the retaining bushing (64) to minimize air leaks around the stop assembly (50) . 6. The locking mechanism of claim 5 wherein the air seal comprises an elastomeric sleeve (263) disposed around the pin (52) and dimensioned to slidingly receive the pin (52) as the stop assembly (50) is activated and released, the spring (162) being disposed over the seal (263) . 7. The locking mechanism of claim 5 wherein the spring (62) is disposed over the pin (52) and the air seal comprises an elastomeric sleeve (163) disposed around the spring and (62) the pin (52) and dimensioned to slidingly receive the spring and pin as the stop assembly is activated and released.

Inventors: BUCHTER RANDOLPH LEE, FABIAN DAVID JAMES, BUCHTER, RANDOLPH, LEE, FABIAN, DAVID, JAMES
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1997
Main classification: B60T17
IPC codes: B60T17, F16L27