Locking mechanism for releasably retaining a power take-off shaft within an output shaft hub

A locking mechanism for releasably fixing an externally splined power take-off shaft to an output shaft of off-highway equipment such as a tractor, said output shaft having a hollow, internally splined hub portion adapted to axially receive the externally splined power take-off shaft to prevent relative rotational movement between the power take-off and output shafts, said locking mechanism comprising:

• a locking member adapted to be supported within a radial opening in the power-take off shaft so as to be radially movable between an outer locking position, wherein said locking member is engageable with a recess formed in the hub potion of the output shaft to prevent relative axial movement between the power take-off shaft and the output shaft, and an inner unlocking position, wherein said locking member is disengaged from said recess in the output shaft to permit such relative axial movement;
• an elongated actuator adapted to be positioned within an inner bore of the power take-off shaft and having a cam surface thereon, said actuator being movable between a first position in which the actuator operably maintains the locking member in its locking position, and a second position which permits radial movement of said locking member to its unlocking position, whereupon return of said actuator to the first position causes the cam surface to operably engage the locking member to move said locking member to its locked position;
• and
• a cap screw adapted to be threadably inserted into a distal end of the power take-off shaft bore and operably engage the actuator to axially move said actuator in a proximal direction.

A power take-off unit of off-highway equipment such as a tractor, comprising:

• an output shaft having a hollow, internally splined hub portion adapted to axially receive an externally splined power take-off shaft to prevent relative rotational movement between the power take-off and output shafts;
• a locking pin axially movable within an inner bore of the power take-off shaft and having a circumferential channel formed on a proximal end portion thereof;
• a plurality of circumferentially spaced locking balls supported within respective spaced radial openings in the power-take off shaft so as to be simultaneously radially movable between outer locking positions, wherein said locking balls are engageable with a circumferential groove formed in the hub portion of the output shaft to prevent relative axial movement between the power take-off shaft and the output shaft, and inner unlocking positions, wherein said locking balls are positioned within the channel in the locking pin to permit such relative axial movement;
• and
• a bias member acting between the locking pin and the power take-off shaft for biasing the locking pin axially toward a first position in which an outer surface of the locking pin engages and operably maintains the locking balls in their locking position, whereby the locking pin is axially movable against the action of the bias member to a second position in which the channel in the locking pin is in substantial alignment with the radial openings in the power take-off shaft to permit radial movement of said locking balls to their unlocking position.

A locking mechanism for releasably fixing an externally splined power take-off shaft to an output shaft of off-highway equipment such as a tractor, said output shaft having a hollow, internally splined hub portion adapted to axially receive the externally splined power take-off shaft to prevent relative rotational movement between the power take-off and output shafts, said locking mechanism comprising:

• a locking pin adapted to be axially movable within an inner bore of the power take-off shaft and having a circumferential channel formed on a proximal end portion thereof;
• a plurality of circumferentially spaced locking balls adapted to be supported within respective spaced radial openings in the power-take off shaft so as to be simultaneously radially movable between outer locking positions, wherein said locking balls are engageable with a circumferential groove formed in the hub portion of the output shaft to prevent relative axial movement between the power take-off shaft and the output shaft, and inner unlocking positions, wherein said locking balls are positioned within the channel in the locking pin to permit such relative axial movement;
• a bias member adapted to be acting between the locking pin and the power take-off shaft for biasing the locking pin axially toward a first position in which an outer surface of the locking pin engages and operably maintains the locking balls in their locking position, whereby the locking pin is axially movable against the action of the bias member to a second position in which the channel in the locking pin is adapted to be in substantial alignment with the radial openings in the power take-off shaft to permit radial movement of said locking balls to their unlocking position;
• and
• a cap screw adapted to be threadably inserted into a distal end of the power take-off shaft bore and operably engage the locking pin to axially move said locking pin in a proximal direction, said cap screw having a length such that the channel in the locking pin is generally aligned with the radial openings in the power take-off shaft when the cap screw is completely tightened, thus ensuring that the locking balls are in the desired unlocking position within the channel.

In combination with a power take-off unit of a tractor having an output shaft for delivering power to agricultural implements, a power take-off shaft assembly releasably fixed to said output shaft, comprising:

• a power take-off shaft having an inner bore and a plurality of circumferentially spaced radial openings formed in a proximal end portion thereof, said power take-off shaft being positioned within a hollow hub portion of the output shaft such that said radial openings are generally in alignment with a circumferential groove formed in said hub portion;
• a plurality of locking balls supported within respective ones of said radial openings for radial movement relative to the axis of the power take-off shaft;
• a locking pin axially movable within said inner bore and having a circumferential channel formed in a proximal end portion thereof for receiving said locking balls;
• and
• a spring acting between the locking pin and the power take-off shaft for biasing the locking pin axially toward a normally locked position in which said locking balls are maintained in operable engagement with the groove in the hub portion of the output shaft to prevent relative axial movement between the power take-off shaft and the output shaft;
• whereby the locking pin is axially movable against the action of the spring from said locked position to an unlocked position in which the channel of the locking pin is generally in alignment with the radial openings in the power take-off shaft to permit inward radial movement of said locking balls from operable engagement with the output shaft to operable engagement with said locking pin channel, thereby permitting removal of the power take-off shaft from the output shaft, said channel having an inclined surface adapted to move the locking balls radially outward upon release and resulting axial movement of the locking pin.

A power take-off assembly, comprising:

• a power take-off shaft having external splines;
• an output shaft adapted to be positively driven and having a hollow hub portion for receiving the power take-off shaft;
• a connector interconnecting the power take-off shaft and output shaft, said connector having internal splines forming a sliding spline connection with the external splines on the power take-off shaft;
• and a plurality of connecting elements forming a connection with the output shaft to prevent relative rotation of the power take-off shaft and the output shaft while allowing rotational movement as a unit;
• means for breaking said connector when binding of the power take-off shaft prevents rotation thereof as a unit with the positively driven output shaft.