Stapler with stack height compensation

1. A powered stapler comprising:

a housing;

a stapling engine within the housing, the stapling engine including a staple driving assembly and a rotational drive train operable to actuate the staple driving assembly, the rotational drive train including a first gear mounted for rotation on a shaft having opposite ends;

a frame at least partially supporting the rotational drive train and including arcuate apertures configured to receive the opposite ends of the shaft and allow the shaft to move along an arcuate path relative to the frame such that the gear on the shaft will remain in a substantially unchanged intermeshing relation with a second gear of the drive train regardless of any movement of the shaft within the apertures in the frame; and

a stack height compensation mechanism integrated with at least one of the frame and the rotational drive train of the stapling engine, the stack height compensation mechanism operable to enable the stapling engine to compensate for varying stack heights of sheets to be stapled by the powered stapler;

wherein the stack height compensation mechanism includes at least one resilient member coupled to the shaft.

2. The powered stapler of claim 1 , wherein the at least one resilient member is adjacent at least one of the apertures, at least one of the opposite ends of the shaft being supported by the at least one resilient member.

3. The powered stapler of claim 1 , further comprising a cam coupled to the first gear for rotation therewith.

4. The powered stapler of claim 3 , wherein the stack height compensation mechanism allows the cam to move relative to the first gear.

5. The powered stapler of claim 4 , wherein the cam is mounted on a second shaft received in an aperture in the first gear, the aperture in the first gear configured to allow the second shaft to move relative to the first gear.

6. The powered stapler of claim 5 , wherein the at least one resilient member at least partially supports the second shaft to constrain movement of the second shaft within the aperture in the first gear.

7. The powered stapler of claim 1 , wherein the stack height compensation mechanism includes a resilient member supporting each of the opposite ends of the shaft.

8. The powered stapler of claim 7 , wherein the movement of the shaft relative to the frame is constrained by the resilient members.

9. The powered stapler of claim 1 , wherein the stack height compensation mechanism does not include any linkage containing a spring.

10. A powered stapler comprising:

a staple driving assembly operable to drive a staple, the staple driving assembly including a driven member;

a rotational drive train operable to actuate the driving assembly, the rotational drive train including a motor and a drive member actuated by the motor;

a frame supporting at least a portion of the rotational drive train; and

a housing surrounding the staple driving assembly, the rotational drive train, and the frame;

wherein the drive member is mounted for rotation with a shaft having opposite ends received in arcuate apertures in the frame such that the shaft is movable with respect to the frame along an arcuate path and the drive member is configured to engage the driven member of the driving assembly, the shaft being movable relative to the frame to enable the staple driving assembly and the rotational drive train to compensate for varying stack heights of sheets to be stapled by the powered stapler;

wherein the ends of the shaft received in the apertures in the frame are also received in resilient members coupled to the frame adjacent the apertures, the movement of the shaft within the apertures being constrained by the resilient members;

wherein the shaft also supports a first gear, and wherein the drive member is a cam coupled to the first gear, and

wherein the rotational drive train further includes a second gear configured to intermesh with the first gear supported on the shaft, and wherein the apertures in the frame are configured such that the gears will remain in a substantially unchanged intermeshing relation regardless of any movement of the shaft within the apertures in the frame.

11. The powered stapler of claim 10 , wherein the resilient members are resilient bushings supported in bushing blocks coupled to the frame.

12. The powered stapler of claim 10 , wherein the drive member includes a pair of cams coupled to the first gear.

13. A powered stapler comprising:

a staple driving assembly operable to drive a staple, the staple driving assembly including a driven member; and

a rotational drive train operable to actuate the driving assembly, the rotational drive train including a motor and a drive member actuated by the motor;

wherein the drive member is mounted for rotation with a shaft and is configured to engage the driven member of the driving assembly, the shaft being supported by a stack height compensation system that allows movement of the shaft to compensate for varying stack heights of sheets to be stapled by the powered stapler, yet restricts movement of the shaft that would otherwise cause a change in an engagement relationship between components of the rotational drive train that cause rotation of the shaft;

wherein the shaft has opposite ends received in arcuate apertures in a support structure, the opposite ends of the shaft being movable alone an arcuate path within the apertures;

wherein the ends of the shaft received in the apertures are also received in resilient members coupled to the support structure adjacent the apertures, the movement of the shaft within the apertures being constrained by the resilient members

wherein the shaft also supports a first gear, and wherein the drive member is a cam coupled to the first gear; and

wherein the drive train further includes a second gear configured to intermesh with the first gear supported on the shaft, and wherein the apertures in the support structure are configured such that the gears will remain in a substantially unchanged intermeshing relation reaardless of any movement of the shaft within the apertures.