I worked on the shaft release button on this linear stapling device while interning at Ethicon in 2014. The device was never released, but it was patented. A link to the patent is at the bottom of this page.
The device was far along when some user testing found that users were having a difficult time removing the shafts. Under the direction of another designer, I explored different button shapes that worked with the existing latch mechanism to make shaft removal easier.
Link to the patent for this device:
