Title of Invention: Independent brake handle assembly
Abstract: A handle assembly, of the type used in railway locomotives, which includes a base plate, a cam mount attached to the base plate, a cam disk and a shaft assembly interconnecting the mount and disk to allow rotation of the disk. The improvement includes a yoke, a bail bar, first and second bearing members anchored to the plate and first and second switches attached to the plate. Pivotally connected to the disk and accommodating a handle, the yoke rotates along with the disk as the handle is moved along its range of motion and tilts as the handle is moved perpendicularly thereto. The bail bar is rotatable between the first and second bearing members. A first mechanism imparts a rotational force to the bail bar so that its middle section presses against an upper portion of the yoke. A stop limits rotation of the bail bar to a point at which the yoke and handle attain an untilted state. Operating against a lower portion of the yoke, a second mechanism provides a counterbalancing force to normally bias the yoke in the untilted state. No matter where the handle is positioned along its range of motion, when it is tilted by a preset amount, the yoke overcomes the rotational and counterbalancing forces so that a third mechanism causes both the first and second switches to change state.
Detailed Description: Part PAC: DETAILED DESCRIPTION OF THE INVENTION
Part PAR: Before describing the invention in detail, the reader is advised that, for the sake of clarity and understanding, identical components having identical functions have been marked where possible with the same reference numerals in each of the Figures provided in this document.
Part PAR_2: FIGS. 2B and 3 illustrate an independent brake handle assembly 100 of a cab control unit 1 for a railway locomotive. This particular independent brake handle assembly 100 is a known mechanism whose construction and operation is shown and explained in Operation & Maintenance Manual Document No. 4208-32, Rev. Date 8/96, published by WABCO. It is described here only to the extent necessary to illustrate the environment in which the invention described below is preferably used.
Part PAR_3: FIG. 3 shows the independent and automatic brake handle assemblies 100 and 200, both of which are built upon and include a common foundation, namely, base plate 150. Among other parts whose constructions and functions are known in the art to which the ensuing invention pertains, the independent brake handle assembly 100 employs base plate 150, a cam mount 120, a cam disk 130, a shaft assembly 125, a yoke 140 and two microswitches 160 and 165. The actuation (or bail off) switch 160 is normally open whereas the loss of power (LOP) bail off switch 165, though of the normally closed type, is normally biased to the open state in the manner described below.
Part PAR_4: The cam mount 120 is attached to base plate 150 by screws, as best shown in FIG. 3. The shaft assembly 125 is used to interconnect cam mount 120 and cam disk 130 so as to allow cam disk 130 to be rotated. Using retaining pin 133, the yoke 140 is pivotally connected near its centerline to the other side of cam disk 130 between hinges 131 and 132. Below its centerline, the yoke on the lower part 145b of its surface 145 is slanted inwardly at approximately a seven degree (7.degree.) angle. The yoke at its top end defines a bore 141 or other receptacle into which secures the lower end of a lever type handle 101.
Part PAR_5: The yoke 140 also defines a bore 146 transversely through its bottom end into which a retainer 147 is screwed. A spring 148 is carried by retainer 147, as shown in FIG. 3. When retainer 147 is screwed into yoke 140, this spring protrudes from surface 145b so as to be in compression between the inside end of retainer 147 and the face of cam disk 130, below hinges 131 and 132, to which slanted surface 145b corresponds. By its compression, spring 148 biases handle 101 and yoke 140 in an untilted state wherein it also compels the normally closed contacts of the LOP bail off switch to assume the open state. Given the slant of surface 145b, this hinge and spring arrangement allows handle 101 (and yoke 140 therewith) to be tilted from vertical (from the perspective of FIG. 3) with respect to cam disk 130 by approximately seven degrees (7.degree.).
Part PAR_6: Yoke 140 and cam disk 130 thus rotate as handle 101 is moved along its range of motion. Viewed from the perspective of FIG. 1, the range of motion for handle 101 is nearly lateral from its release position at the left through the application zone to its full apply position on the right. The extent of rotation for handle 101 over its entire range of motion is approximately ninety degrees (90.degree.).
Part PAR_7: It should be noted that there are two types of cab control units. On one type, the 26 Style Cab Control Unit shown in FIG. 1, the handle unit 2 is oriented vertically. The handle 101 for the 26 Style Unit is to be moved laterally along its range of motion and is to be tilted downwardly when placing it in the actuation position. On another type, the 30 Style Cab Control Unit (not shown), the handle unit is mounted horizontally, i.e., handles pointing upwardly as if the unit were mounted on a table. For the 30 Style Unit, the handle is to be moved back and forth along its range of motion and is to be tilted to the right when placing it in the bail off position.
Part PAR_8: Referring again to FIGS. 2B and 3, the handle 101 is limited to its ninety degree range of motion by stop block 170. Attached to base plate 150, as best shown in FIG. 3, the stop block has a first stop surface 171 and a second stop surface 172. The first stop surface 171 is used as a barrier to prevent rotation of yoke 140 beyond the full apply position by virtue of contact with the upper part of surface 143. Similarly, the second stop surface 172 is used as a barrier to prevent rotation of yoke 140 beyond the release position by virtue of contact with the lower part of surface 143. Stop block 170 thus prevents the handle 101 (and thus yoke 140 and cam disk 130) from being rotated beyond the ninety degree range of motion.
Part PAR_9: As shown in FIGS. 2B and 3, the bail off microswitch 160 and the LOP bail off microswitch 165 both mount to and, therefore, move along with the yoke 140. When handle 101 is tilted to and held in the actuation position while the railcar and locomotive brakes are applied via the automatic brake handle, the bail off and LOP bail off microswitches 160 and 165 are both compelled to assume the closed state.
Part PAR_10: Regarding the purpose for the bail off switch 160, the cab control computer monitors the bail off switch via harness 180 as shown in FIG. 2B. When the bail off switch closes, a circuit is completed and the cab control computer conveys a signal indicative of the closure to the brake control computer. The brake control computer responds by commanding the IAR control portion to charge the actuating pipe. Specifically, the IAR control portion contains a quick release magnet valve (QRMV) that the brake control computer energizes thereby allowing air from the main reservoir to charge the actuating pipe. Once the No. 13 pipe is pressurized to approximately 25 psi, the aforementioned pressure switch 13A closes. The brake control computer senses closure of the pressure switch and responds by commanding the BC control portion to release the pressure from the brake cylinders of the locomotive. The brake control computer will continue to allow the pressure to drop as long as the handle is held (i.e., tilted) in the bail off position.
Part PAR_11: The handle can be allowed to move (i.e., untilt) out of its bail off position at any time. Then, depending on the position that handle 101 currently occupies or to which it is rotated in its range of motion, the brake control computer will command the BC control portion to keep the locomotive brake cylinders at whatever pressure they currently retain or to increase their pressure to the desired level. The independent brake handle 101 can thus be used to bail off the locomotive brakes while keeping the railcar brakes engaged.
Part PAR_12: Regarding the purpose for the LOP bail off switch 165, should the train suffer a loss of power, both the railcar and the locomotive brakes can be applied in an emergency by moving the automatic brake handle to the emergency position. For a locomotive operating in the previously described LEAD CUT-IN mode, pressure will then be developed in the brake cylinders of both the locomotives and the railcars of the train via special pneumatic back-up brake equipment.
Part PAR_13: Certain railroad operating authorities have requested that their locomotives be capable of bailing off the locomotive brakes under such loss of power conditions. For those customers, the independent brake handle assembly 100 via its LOP bail off switch 165 can be used to actuate the locomotive brakes while keeping the railcar brakes engaged. Under loss of power conditions, a relay known as the LOP relay deenergizes in which state it connects the power side of the QRMV to back up power circuitry. When handle 101 is tilted to the actuation position, LOP bail off switch 165 is compelled to close thereby providing ground to the return side of the QRMV. Consequently, when handle 101 is tilted to the actuation position under loss of power conditions, the QRMV of the IAR control portion energizes thereby allowing air from the main reservoir to charge the No. 13 pipe. The BC control portion then responds by reducing the pressure in the brake cylinders of the locomotive. The pressure in the locomotive brake cylinders will continue to be bailed off (i.e., actuated) as long as the independent brake handle is held (i.e., tilted) in the actuation position.
Part PAR_14: The harness 180, as best shown in FIG. 2B, is used to connect the terminals of the actuation and LOP bail off microswitches to the cab control computer and/or other electrical circuitry. Consequently, the harness 180 must endure a considerable amount of flexing whenever the handle (and yoke 140 to which the switches mount) is rotated along its range of motion and/or tilted to its bail off position. As it is attached to the top end of yoke 140, the LOP bail off switch 165 is situated where it is at great risk of damage by objects that could protrude through the opening for handle 101 in the cover of the handle unit 2. Moreover, the actuation switch 160, attached to the bottom end of the yoke, requires periodic adjustment of its actuating leaf due to such movement of the harness 180. Due to the solder type connections, the mounting of the two microswitches on the yoke and the stresses of movement, this microswitch and harness arrangement has been shown to be prone to damage.
Part PAR_15: The construction and operation of the independent brake handle assembly 100 has been described herein to the extent necessary to understand the environment in which the ensuing invention is preferably intended to be used. It should be understood, however, that this constitutes a brief and simplified explanation of how the prior art handle assembly 100 works and its role in the brake control system of a train.
Part PAR_16: Having now described the environment in which the invention is preferably used, FIGS. 4 and 5 illustrate the invention--an improved independent brake handle assembly 300. The improved assembly 300 includes a base plate 350, a cam mount 120, a cam disk 130, a shaft assembly 125, a yoke 340, an actuation (or bail off) microswitch 360 and a loss of power (LOP) bail off microswitch 365. The improved handle assembly 300 further includes a bail bar 320, a first bearing member 330 and a second bearing member 370.
Part PAR_17: The base plate 350 features the new mounting holes that are necessary to accommodate the new components, e.g., the holes used to mount the first and second bearing members 330 and 370 and the switches 360 and 365. The cam mount 120 attaches to base plate 350 typically by screws and the shaft assembly 125 interconnects cam mount 120 and cam disk 130, as shown in FIG. 5, so as to allow cam disk 130 to be rotated. The actuation and LOP bail off microswitches 360 and 365 each attach to base plate 350 preferably by means of a bracket such as the type denoted by reference numerals 361 and 366 in FIG. 4.
Part PAR_18: As yoke 340 does not accommodate any switches, it can be considerably smaller than the prior art yoke 140. A retaining pin, such as pin 133 shown in FIG. 3, pivotally connects the yoke 340 approximate its centerline to the other side of cam disk 130 between hinges 131 and 132. Below its centerline, however, the yoke 340 on its lower part still retains the inwardly slanted surface that faces cam disk 130. Like the slanted surface 145b shown in FIG. 3, this surface is inclined inwardly by approximately seven degrees (7.degree.). The top end of yoke 340 defines bore 341 or other receptacle into which secures the lower end of the lever type handle 101.
Part PAR_19: Yoke 340 and cam disk 130 thus both rotate as handle 101 is moved along its range of motion. Viewed from the perspective of FIG. 4, the handle 101 resides in the application zone with the release position to the right and the full apply position to the left. Moving the handle through its entire range of motion causes the combined yoke and cam disk assembly to rotate by approximately ninety degrees (90.degree.).
Part PAR_20: The first and second bearing members 330 and 370 attach by screws or similar means to base plate 350. Each member features bearings or similar apparatus in which to hold the respective ends of bail bar 320 so that the bail bar in its entirety can be rotated. The bail bar 320 is shaped so that its middle section is not coaxial with its ends. As shown in FIG. 4, bail bar 320 may be shaped somewhat like a handle for a bucket with its middle section upraised with respect to its ends. The middle section, for example, may take the shape of a rectangle or of a semicircle. As described below, this allows the middle section to operate against the upper portion of yoke 340 on the side of yoke 340 opposite cam disk 130.
Part PAR_21: The improved handle assembly 300 further features a means 380 for imparting a rotational force to bail bar 320 so that its middle section forcibly presses against the upper portion of yoke 340. In its preferred embodiment, this means includes a tension arm 381, spring 382 and plunger 383. As best shown in FIG. 5, tension arm 381 is rotatable with and has a tail end affixed to that end of bail bar 320 that protrudes through the second bearing member 370. Preferably, tension arm 381 defines a bore in its tail end within which the second end of bail bar 320 anchors. Spring 382 is preferably housed in a bore defined in the base of second bearing member 370. Plunger 383 serves as a cap on top of spring 382. Under compression by virtue of the angle at which tension arm 381 is disposed, the spring 382 and plunger 383 operate against the head end of tension arm 381. As viewed from the perspective of FIG. 4, the means 380 compels the bail bar 320 by inward rotation to force its middle section against the upper portion of yoke 340.
Part PAR_22: The second bearing member 370 features a stop block 375 to prevent the yoke 340 and handle therewith from moving beyond the release and full apply positions. The first surface 376 of stop block 375 prevents rotation of yoke 340 beyond the full apply position by virtue of contact with the upper part of surface 343. The second surface 377 of block 375 prevents rotation of yoke 340 beyond the release position by virtue of contact with the lower part of surface 343. Stop block 375 thus prevents the handle 101 (and thus yoke 340 and cam disk 130) from being rotated beyond the ninety degree range of motion.
Part PAR_23: Stop block 375 also limits the rotation of bail bar 320 to the point at which the handle and yoke attain the untilted state. The perspective view of FIG. 4 illustrates that surface 378 of block 375 serves as a barrier that prevents bail bar 320 from rotating to the point at which both the yoke and handle would be forced inwardly beyond the untilted state.
Part PAR_24: The improved handle assembly 300 further features a means 390 for providing a counterbalancing force to normally bias the yoke and handle in the untilted state. The means 390 is preferably designed to operate against the lower portion of the yoke. In its preferred embodiment, this means includes a bore 346, retainer 347 and spring 348. The bore 346 is defined transversely through the bottom end of yoke 340. Bore 346 is smaller than the bore 146 shown in FIG. 3 due, at least in part, to the smaller size of yoke 340. Designed to screw or otherwise secure into bore 346, retainer 347 carries spring 348 in a manner similar to that shown in FIG. 3. When retainer 347 is secured into yoke 340, the other end of spring 348 protrudes from the slanted surface so as to be in compression between the inside end of retainer 347 and the face of cam disk 130, preferably below hinges 131 and 132, to which the slanted surface corresponds. Spring 348 thus biases yoke 340 and handle 101 in the untilted state. Given the incline of the slanted surface of yoke 340, this hinge and spring arrangement also allows handle 101 (and yoke 340 therewith) to be tilted with respect to cam disk 130 by approximately seven degrees (7.degree.) against the rotational force that operates on bail bar 320. Moving the handle perpendicularly to its range of motion causes this tilting of the handle and yoke assembly.
Part PAR_25: The improved handle assembly 300 also includes a means 400 for engaging the actuation and LOP bail off microswitches 360 and 365. In its preferred embodiment, this engaging means features a trip arm denoted by reference numeral 410 in FIG. 4. The tail end of trip arm 410 is rotatable with and affixed to that end of bail bar 320 that protrudes through the first bearing member 330. Preferably, the trip arm defines a bore in its tail end within which the first end of bail bar 320 anchors. The head end of trip arm 410 is disposed between, and can therefore engage both of, the microswitches 360 and 365. No matter where it is positioned along its range of motion, when the handle 101 is tilted by approximately seven degrees or by any other preset amount, the yoke 340 moves against the rotational force of bail bar 320 and further compresses spring 348. As the independent brake handle 101 is so tilted, the bail bar 320 rotates outwardly as viewed from the perspective of FIG. 4. This causes trip arm 410 to rotate about its tail end so that its head end causes both the actuation switch 360 and the LOP bail off switch 365 to change state.
Part PAR_26: Due to the environment in which the invention is preferably intended to be used, the actuation microswitch 360 is preferably of the normally open type whereas the LOP bail off switch 365 is preferably of the normally closed type. As for the former, when the handle is tilted to the bail off position, the actuation switch 360 closes thereby completing a circuit in response to which the cab control computer conveys the aforementioned signal indicative of such closure to the brake control computer. As for the latter, the LOP bail off switch 365 has three internal contacts (common, open and closed) and a lever to engage them. When handle 101 occupies the untilted state, the head end of trip arm 410 forces this lever to connect the common and closed contacts. When the handle is tilted to the bail off position, however, this lever returns to its default position in which it connects the common and open contacts of LOP bail off switch 365 thereby providing a ground connection to the aforementioned return side of the QRMV. Consequently, when the independent brake handle is tilted to the actuation position under loss of power conditions, the LOP bail off switch 365, in conjunction with the LOP relay, enables the QRMV of the IAR control portion to energize thereby allowing air from the main reservoir to charge the No. 13 pipe.
Part PAR_27: It should be noted that each of the foregoing means (i.e., 380, 390 and 400) may be implemented using various other arrangements of the same parts or even different parts that together perform the same function as the previously described structure. The ensuing claims are therefore intended to encompass all of these mechanisms and any variations thereof.
Part PAR_28: The presently preferred embodiment for carrying out the invention has now been set forth in detail according to the Patent Act. Those persons of ordinary skill in the art to which this invention pertains may, nevertheless, recognize various alternative ways of practicing the invention without departing from the spirit and scope of the following claims. Those of such skill will also recognize that the foregoing description is merely illustrative and not intended to limit any of the ensuing claims to any particular narrow interpretation.
Part PAR_29: Accordingly, to promote the progress of science and useful arts, we secure for ourselves by Letters Patent exclusive rights to all subject matter embraced by the following claims for the time prescribed by the Patent Act.


{'bibliographic_information': "{'Patent Number': '060856084', 'Series Code': '9', 'Application Number': '044295&', 'Application Type': '1', 'Art unit': '362', 'Application Filing Date': '19980319', 'Title of Invention': 'Independent brake handle assembly', 'Issue Date': '20000711', 'Number of Claims': '20', 'Exemplary Claim Number(s)': '1', 'Assistant Examiner': 'Joyce; William C', 'Primary Examiner': 'Jeffery; John A.', 'Number of Drawing Sheets': '6', 'Number of figures': '6'}", 'source_file': './grant/2000/pftaps20000711_wk28.txt', 'source_data': 'USPTO-Grant'}