Patent Description:
It is often necessary for the drive train of an aircraft to be mechanically locked (unable to rotate) for certain maintenance procedures and during transportation to prevent damage. On many rotorcraft transmissions, locking out of the device requires the installation of separate support equipment that typically bolts on a gearbox case. In some situations, the gearbox needs to be opened up and exposed to atmosphere to access a locking location. Some methods include the removal of a sealed cover over the interconnecting drive train section of the gearbox, and the installation of a tool that consists of a screw drive to lock the drive train. But there are problems with the prior solutions. The removal of the sealed cover significantly increases the risk of corrosion due to the environment exposure and possible water intrusion. The process requires a tool that is expensive to procure and is large/heavy.

<CIT> discloses a mechanism for limiting rotation of a rotatably mounted first shaft. The mechanism includes a housing in which the first shaft is rotatably supported; a torque input coupled to the first shaft; and a torque output coupled to the first shaft; a second shaft rotatably supported by the housing and movable between a first axial position in which the second shaft does not engage the first shaft and a second axial position in which the second shaft engages the first shaft; at least one member attached to the second shaft which projects radially from the second shaft. The housing has an inner cavity with at least one surface which engages the at least one member which projects radially at first and second angular positions of the shafts to provide for a limited degree of angular rotation of the shafts when the second shaft is in the second axial position.

<CIT> discloses a gearbox assembly. The assembly includes a housing, an output shaft, a wheel gear, an input shaft, a torsion bar, an electric motor, a worm gear and a key lock. The wheel gear is be fixed to the output shaft for engagement with a wheel gear. The torsion bar connects the input shaft to the output shaft. The worm gear is rotationally fixed to the rotor and engages the wheel gear to transfer torque from the motor to the output shaft. The key lock includes an adapter, an annular outer part, a web, and a locking collar. The key lock is fixed to the housing and is movable between an extended position in which a part of the key lock engages the locking collar and a retracted position in which the part is held clear of the locking collar.

<CIT> discloses a parking lock for a transmission. A transmission shaft, a transmission housing, a locking ring, a control element and a locking catch are disclosed. In this case, the locking catch is arranged moveably at a movement angle, wherein the movement of the locking catch causes an axial movement of the locking ring, and wherein, in an activated state of the locking ring, there is a form-fitting connection between the transmission shaft, transmission housing and locking ring.

One embodiment under the present invention comprises a lockout device for a gearbox.

The device comprises a housing comprising a hole therethrough and configured to be fixedly coupled to the gearbox; a cover detachably coupled to the housing; and a shaft detachably coupled to the cover and configured to pass through the hole, the shaft comprising a plurality of teeth at one end and a receiving slot on a distal end, the plurality of teeth configured to engage a portion of a drive train within the gearbox and transmit rotation from the shaft to the drive train. It further comprises an inner collar configured to sit around the shaft and at least partially between the shaft and the housing, the inner collar comprising a plurality of threadless holes; and an outer collar configured to sit around the shaft and at least partially between the inner collar and the housing, the outer collar comprising a plurality of threaded holes configured to receive a plurality of bolts passing through the plurality of threadless holes, wherein rotation of the plurality of bolts can adjust the relative position of the inner collar and the outer collar, wherein as the inner collar and the outer collar are pulled closer together the inner collar is pushed against the shaft and restricts a displacement of the shaft within the hole.

The present invention further relates to a method of performing a lockout operation to torque and lock a drive train within a gearbox. The method comprises unscrewing a cover from its coupling to a housing, the housing comprising a hole therethrough and configured to be fixedly coupled to the gearbox; and uncoupling the cover from a shaft, the shaft configured to pass through the hole and comprising a first plurality of teeth at one end and a socket head on a distal end, the shaft configured to be translatable along its axis, wherein coupling the shaft to the cover prevents the shaft from engaging the drive train. Further steps include manipulating the shaft so as to engage a second plurality of teeth on the drive train with the first plurality of teeth so as to transmit rotation from the shaft to the drive train, and applying a torque to the drive train by rotating the socket head. A further step is rotating a plurality of threaded bolts coupled to a plurality of threadless holes in an inner collar and a plurality of threaded holes in an outer collar, the inner collar configured to sit around the shaft and at least partially between the shaft and the housing, the outer collar configured to sit around the shaft and at least partially between the inner collar and the housing, wherein rotating the plurality of threaded bolts can adjust the relative position of the inner collar and the outer collar, wherein as the inner collar and the outer collar are pulled closer together the inner collar is pushed against the shaft and restricts a displacement of the shaft within the hole.

This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an indication of the scope of the claimed subject matter.

For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:.

The present invention includes embodiments for an integrated gearbox lockout device that improves upon the prior art and solves the problems associated with prior approaches. Certain embodiments can utilize keyless locking technology to keep a gearbox from rotating when the lockout device is engaged. Furthermore, embodiments of the lockout device can remain installed on the gearbox and perform its functions while maintaining a seal between the environment and the internals of the gearbox.

Benefits of embodiments under the present disclosure include, but are not limited to:.

One embodiment of a lockout device under the present disclosure is shown in <FIG> shows a cut-away view of a lockout device <NUM> coupled to a gearbox <NUM>, similar to the gearbox <NUM> of <FIG>. Lockout device <NUM> comprises shaft <NUM>, outer collar <NUM>, inner collar <NUM>, housing <NUM>, and cover <NUM>. Screws <NUM> couple cover <NUM> to housing <NUM>. While the aircraft is in use (or is otherwise not in a lockout operation) cover <NUM> will preferably be kept in place to protect housing <NUM> and shaft <NUM> from wear and tear. When a user wishes to perform a lockout operation, cover <NUM> can be removed by removing screws <NUM>. When not in a lockout operation, shaft <NUM> with teeth <NUM> will sit to the left (in the view of <FIG>) of teeth <NUM> of drive train <NUM>. When a user performs a lockout operation, cover <NUM> is removed and then shaft <NUM> can be pushed to engage teeth <NUM>. Socket head or receiving slot <NUM> in shaft <NUM> can receive a socket wrench operated by a user. The user can use the socket wrench to push in shaft <NUM> to engage teeth <NUM> with teeth <NUM>, and then to rotate the shaft <NUM> (and by extension the gearbox <NUM>) so as to torque up gearbox <NUM> and then restrain further movement during the lockout operation.

Further description of the movement of shaft <NUM> and the lockout device <NUM> can be provided with respect to <FIG>, <FIG> and <FIG>. Reference numbers are kept consistent between <FIG> so as to assist in illustrating the movement of the described components. <FIG> shows a view of lockout device <NUM> unengaged from teeth <NUM> of gearbox <NUM>. <FIG> shows a view of lockout device <NUM> engaged in teeth <NUM>. <FIG> shows a view of lockout device <NUM> from outside of gearbox <NUM>.

Screws <NUM> (shown in ghost form in <FIG> and <FIG> because they would be removed with the cover <NUM>) are used to couple housing <NUM> to cover <NUM> and can be removed when a lockout operation is desired. Bolts <NUM> couple housing to gearbox <NUM>. Hex screws <NUM> couple inner collar <NUM> to outer collar <NUM>. Ring <NUM> along shaft <NUM> prevents the leftward movement (in this view) of inner collar <NUM> along the exterior of shaft <NUM>. Additionally, ring <NUM> can prevent shaft <NUM> from being pressed too far into gearbox <NUM>. Once a user has removed cover <NUM>, the user may push rightward (in this view) shaft <NUM> to engage teeth <NUM>. The user can then rotate hex screws <NUM> (e.g., in a clockwise direction) - this will pull inner collar <NUM> and outer collar <NUM> toward each other. In the view shown, inner collar <NUM> will move right with regard to outer collar <NUM> and vice versa. This motion will force inner collar <NUM> against the surface of shaft <NUM> and lock the rotation of shaft <NUM>, and by extension gearbox <NUM> and drive train <NUM> because shaft <NUM> is engaged with teeth <NUM> via teeth <NUM>. The inner collar <NUM> and outer collar <NUM> engage each other along line <NUM>, forcing each other in the movements described and thereby causing the locking functionality. Hex screws <NUM> pass through unthreaded holes in inner collar <NUM> and engage threaded holes in outer collar <NUM>. The rotation of hex screws <NUM> pulls outer collar <NUM> and inner collar <NUM> together and forces inner collar <NUM> downward against the shaft <NUM>.

Holes <NUM> in inner collar <NUM>, visible in <FIG>, can be threaded. Screws or bolts placed here can be screwed in and can engage a flat face of outer collar <NUM>. Rotating the screws/bolts sufficiently can push against the outer collar and move inner collar <NUM> leftward (from the view of <FIG>) and create additional freedom for the rotation of shaft <NUM>. The screws or bolts used in holes <NUM> can be hex screws <NUM>. Hex screws <NUM> can be removed from the threaded holes in outer collar <NUM> and threaded into holes <NUM>. Removing hex screws <NUM> from outer collar <NUM> and threading them into holes <NUM> can be part of ending a lockout operation and preparing the gearbox for use.

O-ring <NUM> provides sealing protection to keep any fluids or other material from entering gearbox <NUM> through the lockout device <NUM>. Rims <NUM> of housing <NUM> can be shaped to abut the right edge (in this view) of outer collar <NUM> and to restrain rightward movement of outer collar <NUM> and inner collar <NUM> along shaft <NUM>. Cover <NUM>, or a portion thereof, can be clear or transparent and allow a user to visually inspect a status of lockout device <NUM>. Alternatively, an indicator, such as a toggle or flipped switch due to placement of the lockout device <NUM> components, can provide a user an indication of the status of lockout device <NUM> and/or gearbox <NUM>.

As seen in <FIG>, cover <NUM> has a ridge <NUM> that engages slot <NUM> on shaft <NUM>. While the aircraft is in use and apart from times during lockout operations, ridge <NUM> and slot <NUM> hold shaft <NUM> in place with respect to cover <NUM> and prevent the engagement of teeth <NUM> with teeth <NUM>. Housing <NUM> can comprise a slot or ridge for an o-ring <NUM> for engaging a portion of gearbox <NUM> to hold housing <NUM> stationary with respect to gearbox <NUM>. The o-ring can provide an interference fit, sealing, and/or friction, between the housing and the gearbox. A portion of the interior of housing <NUM> can be hollow so as to save weight.

Socket head <NUM> can be hex-shaped for use with a socket wrench when torquing shaft <NUM> and gearbox <NUM>. Shaft <NUM> can also comprise threaded hole or receiving slot <NUM> at the bottom of socket head <NUM>. Threaded hole <NUM> can be used with a threaded device to pull out shaft <NUM> if it gets pressed in too far. Socket head <NUM> can comprise other shapes besides a hexagonal shape. In some embodiments socket head <NUM> could comprise spline teeth that engage a tool for pulling out shaft <NUM>. Socket head <NUM> could be square-shaped in other embodiments. Other shapes are possible as well if they allow for torquing the system.

Reference has been made to hex-shaped receiving components, or screws, bolts, screw-driver compatible components, Phillips head compatible components, etc. While the Figures show certain embodiments, other shaped components can be used. For example, a hex-shaped socket head <NUM> is shown. But other embodiments could comprise a pentagonal-shaped head, Phillips screwdriver head, proprietary-shaped head, spline teeth that can be engaged, and other styles. The current disclosure is not limited to a specific set up regarding the use of hex or other shaped or compatible components.

<FIG> shows a method embodiment <NUM> under the present disclosure. Step <NUM> is unscrewing a cover from its coupling to a housing, the housing comprising a hole therethrough and configured to be fixedly coupled to the gearbox. Step <NUM> is uncoupling the cover from a shaft, the shaft configured to pass through the hole and comprising a first plurality of teeth at one end and a socket head on a distal end, the shaft configured to be translatable along its axis, wherein coupling the shaft to the cover prevents the shaft from engaging the drive train. Step <NUM> is manipulating the shaft so as to engage a second plurality of teeth on the drive train with the first plurality of teeth so as to transmit rotation from the shaft to the drive train. Step <NUM> is applying a torque to the drive train by rotating the socket head. Step <NUM> is rotating a plurality of threaded bolts coupled to a plurality of threadless holes in an inner collar and a plurality of threaded holes in an outer collar, the inner collar configured to sit around the shaft and at least partially between the shaft and the housing, the outer collar configured to sit around the shaft and at least partially between the inner collar and the housing, wherein rotating the plurality of threaded bolts can adjust the relative position of the inner collar and the outer collar, wherein as the inner collar and the outer collar are pulled closer together the inner collar is pushed against the shaft and restricts a displacement of the shaft within the hole.

<FIG> can help illustrate additional views of a lockout device embodiment and the performance of a lockout procedure and ending the lockout for use of the aircraft.

<FIG> displays lockout device <NUM>, comprising a housing <NUM> and cover <NUM>, coupled to gearbox <NUM>. Bolts <NUM> couple cover <NUM> to housing <NUM>. Bolts <NUM> couple housing <NUM> to gearbox <NUM>.

Bolts <NUM> can be removed to begin a lockout procedure. As seen in <FIG>, cover <NUM> has been removed. Holes <NUM> on housing <NUM> are now empty after the removal of bolts <NUM>. Shaft <NUM> can now be seen. Socket head <NUM>, ring <NUM>, and threaded hole <NUM> are also seen. Inner collar <NUM> is seen with threaded bolts <NUM> that couple inner collar <NUM> to outer collar <NUM> (not shown in <FIG>). Threaded holes <NUM> are shown, empty right now but available to receive threaded bolts <NUM> to assist in pushing inner collar <NUM> away from outer collar <NUM>.

Referring to <FIG>, threaded bolts <NUM> can be loosened, which will loosen the grip of inner collar <NUM> and outer collar <NUM> on shaft <NUM>. Referring to <FIG>, shaft <NUM> can now be pushed axially into gearbox <NUM> so as to engage gear <NUM>. Shaft <NUM> can comprise teeth <NUM> that engage gear <NUM>. Gear <NUM> can comprise a portion of a drive train <NUM>. Ring <NUM> on shaft <NUM> prevents the shaft <NUM> from being pressed too far into gearbox <NUM>.

Moving to <FIG>, after shaft <NUM> has been moved to engage gear <NUM>, threaded bolts <NUM> can be tightened, drawing outer collar <NUM> and inner collar <NUM> closer together and pushing inner collar <NUM> more tightly around shaft <NUM>. After sufficient tightening (<FIG>) the shaft <NUM> will be "locked" in gear <NUM>. Cover <NUM> can be reattached and the vehicle and/or gearbox can be shipped, undergo maintenance or storage, or as otherwise desired.

Claim 1:
A lockout device (<NUM>) for a gearbox (<NUM>), comprising:
a housing (<NUM>) comprising a hole therethrough and configured to be fixedly coupled to the gearbox (<NUM>);
a shaft (<NUM>) detachably coupled to the housing and configured to pass through the hole, the shaft comprising a plurality of teeth (<NUM>) at one end and a receiving slot (<NUM>) on a distal end, the plurality of teeth configured to engage a portion of a drive train (<NUM>) within the gearbox and transmit rotation from the shaft to the drive train;
an inner collar (<NUM>) configured to sit around the shaft and at least partially between the shaft and the housing, characterized by the inner collar comprising a plurality of threadless holes; and
an outer collar (<NUM>) configured to sit around the shaft and at least partially between the inner collar and the housing, the outer collar comprising a plurality of threaded holes configured to receive a plurality of bolts (<NUM>) passing through the plurality of threadless holes, wherein rotation of the plurality of bolts can adjust the relative position of the inner collar and the outer collar, wherein as the inner collar and the outer collar are pulled closer together the inner collar is pushed against the shaft and restricts a displacement of the shaft within the hole.