Transmission control system

For a transmission including input and output shafts and gear coupling means movable axially of said output shaft between a first neutral non-power-transmitting position and a second power-transmitting position wherein power is transmitted from said input shaft to said output shaft, a gear shifting arrangement for moving said coupling means between said first and second positions comprising:

• shift fork means including lug means comprising a pair of upstanding drive lugs between which said drive element is disposed and against which said drive element reacts to displace said shift fork means engageable with said coupling means and displaceable generally parallel to said output shaft for moving said coupling means axially thereof,
• rotatable shaft means disposed adjacent to said fork means,
• motor means for selectively rotating said shaft means, and
• drive means including a drive element which is displaced axially with respect to said shaft means during rotation thereof for operatively connecting said shaft means with said fork means, whereby selective rotation of said shaft means by said motor means in one direction displaces said fork means to move said coupling means from said first position toward said second position, and rotation of said shaft means in the other direction displaces said fork to move said coupling means from said second position toward said first position.

For a transmission including input and output shafts and gear coupling means movable axially of said output shaft between a first neutral non-power-transmitting position and a second power-transmitting position wherein power is transmitted from said input shaft to said output shaft, a gear shifting arrangement for moving said coupling means between said first and second positions comprising:

• shift fork means engageable with said coupling means and displaceable generally parallel to said output shaft for moving said coupling means axially thereof,
• rotatable shaft means disposed adjacent to said fork means,
• motor means for selectively rotating said shaft means,
• gear means for transmitting movement of said motor means into rotation of said shaft means,
• means accommodating axial displacement of said shaft means with respect to said gear means, and
• gear support means limiting axial movement of said gear means, and
• drive means including a drive element which is displaced axially with respect to said shaft means during rotation thereof for operatively connecting said shaft means with said fork means, whereby selective rotation of said shaft means by said motor means in one direction displaces said fork means to move said coupling means to move said coupling means from said first position toward said second position, and rotation of said shaft means in the other direction displaces said fork to move said coupling means from said second position toward said first position.

In a transmission including input and output shafts, a plurality of gear pairs respectively disposed along said input and output shafts wherein each gear pair provides a power-transmitting gear ratio, and first and second gear coupling means movable axially of said output shaft, each gear coupling being movable between a neutral non-power-transmitting position and at least one power-transmitting position wherein power is transmitted from said input shaft to said output shaft through one of said gear pairs, a gear-shifting arrangement for selectively moving said first and second gear coupling means comprising:

• first and second shift fork means respectively engageable with said first and second gear couplings and axially displaceable with respect to said input shaft,
• rotatable shaft means disposed generally parallel to said input shaft,
• motor means operatively connected with said shaft means for selective rotation thereof,
• first and second drive means for operatively connecting said shaft means with said first and second shift fork means, respectively, for urging the displacement of said first and second shift fork means when said shaft means is rotated by said motor means, and
• control means for selectively activating said motor means to rotate said shaft means and for selectively preventing displacement of said first and second shift fork means.

An apparatus for changing the speed ratio of a geared transmission, said transmission including a housing which rotatably carries an input shaft which carries a first gear for rotation therewith, a rotatable output shaft which rotatably carries a second gear which is enmeshed with said first gear, and sliding coupling means, axially shiftable along said output shaft between a first engaged position for connecting said output shaft to said second gear for rotation therewith and a neutral position, comprising:

• (a) a threaded shaft carried by said housing;
• (b) reversible motor means carried by said housing, for rotating said threaded shaft;
• and
• (c) shift fork means, carried by said housing and coupled to said threaded shaft, for moving said coupling means between its neutral and its first engaged position, whereby the rotation of said motor means in one direction rotatably connects said input shaft and said output shaft and rotation of said motor means in the opposite direction disengages said input shaft from said output shaft.