Spline arrangement for rotatably coupling two members

A rotatable combination, said combination defining a longitudinally extending rotational axis and comprising:

• a shaft disposed coaxially with said rotational axis, said shaft defining a distal end and having a first plurality of longitudinally extending and circumferentially spaced splines, said first plurality of splines projecting radially outwardly from said shaft;
• a body defining a substantially cylindrical opening, said opening disposed coaxially with said rotational axis and having a second plurality of longitudinally extending and circumferentially spaced splines, said second plurality of splines projecting radially inwardly within said opening and extending substantially parallel to said rotational axis;
• wherein said first plurality of splines include a first longitudinally extending section and a second longitudinally extending section, said first longitudinal section defining a first orientation relative to said rotational axis and said second longitudinal section defining a second orientation relative to said rotational axis, said second orientation differing from said first orientation and defining a substantially constant angle with said rotational axis, said distal end of said shaft being insertable into said opening to thereby engage said first and second plurality of splines, said first longitudinal section positioned between said second longitudinal section and said distal end;
• and
• wherein engagement of said first longitudinal section with said second plurality of splines defines a first resistance to relative longitudinal movement between said shaft and said body and engagement of said second longitudinal section with said second plurality of splines defines a second resistance to relative longitudinal movement between said shaft and said body, said second resistance being greater than said first resistance for a common interdigitated longitudinal length;
• and wherein engagement of said second longitudinal section with said second plurality of splines rotatably drivingly couples said shaft and said body in a substantially backlash-free engagement.

A method of rotatably coupling a first member with a second member wherein the first and second members define a longitudinally extending rotational axis, said method comprising:

• providing the first member with a first plurality of splines, the first plurality of splines including a first longitudinally extending section and a second longitudinally extending section, the first longitudinal section defining a first orientation relative to the rotational axis and the second longitudinal section defining a second orientation relative to the rotational axis, the second orientation differing from the first orientation and defining a substantially constant angle with the rotational axis;
• providing the second member with a second plurality of splines, the second plurality of splines extending substantially parallel to the rotational axis;
• coaxially positioning the first and second members;
• rotationally aligning the first and second members by engaging the first longitudinal section of the first plurality of splines with the second plurality of splines;
• applying a first longitudinally directed force to the first and second members to longitudinally slide the first member relative to the second member while the first longitudinal section is engaged with the second plurality of splines to bring the second longitudinal section into engagement with the second plurality of splines;
• and
• applying a second longitudinally directed force to the first and second members while the second longitudinal section is engaged with the second plurality of splines to bring a substantial portion of the longitudinal length of the second longitudinal section into engagement with the second plurality of splines wherein the second longitudinally directed force is greater than the first longitudinally directed force and wherein engaging the substantial portion of the longitudinal length of the second longitudinal section with the second plurality of splines rotatably drivingly couples the first and second members in a substantially backlash-free engagement.