In 1970, the new A711 block for 1298 cc and A711M block for 1599 cc were introduced with thicker block wall, square main bearing caps, large diameter cam followers and wider cam lobes, with the latter block having a 7 / 16 " taller deck height, together with a return to the flat head.
32.
More modern designs have the camshaft on top of the cylinder head, pushing directly on the valve stem ( again through cam followers, also known as tappets ), a system known as " overhead camshaft "; if there is just one camshaft, this is a single overhead cam or " SOHC " engine.
33.
The cam followers used in Sportster engines, K models, big twin side valve models, and the side-valve W model series were a slightly shorter version of the followers used in the larger motors, but with the same diameter body and diameter roller follower since 1929 . The company used similar cam followers for decades with minor changes, from the 1929 to the Eighties.
34.
The cam followers used in Sportster engines, K models, big twin side valve models, and the side-valve W model series were a slightly shorter version of the followers used in the larger motors, but with the same diameter body and diameter roller follower since 1929 . The company used similar cam followers for decades with minor changes, from the 1929 to the Eighties.
35.
An additional " low velocity " selector latch is also engaged by certain keys, such as'.'and'_', which require a reduced striking force so as not to cut the paper; this selector latch engages the low velocity control cam follower, which pulls the low velocity cable connected to the cam in the carrier, causing the low velocity lobe to be used instead of the usual high velocity lobe.
36.
For jerky motion in one direction, you could combine a cam with a second concentric riser shaft that is pushed by the cam follower in one direction, but not the other, say with saw teeth on both that lock in one direction but slide in the other ( you'd need a fixed sleeve around both vertical shafts to keep them in contact, and it would also need to have saw teeth to lock with the riser shaft to prevent it from falling back down as the cam follower descends ):
37.
For jerky motion in one direction, you could combine a cam with a second concentric riser shaft that is pushed by the cam follower in one direction, but not the other, say with saw teeth on both that lock in one direction but slide in the other ( you'd need a fixed sleeve around both vertical shafts to keep them in contact, and it would also need to have saw teeth to lock with the riser shaft to prevent it from falling back down as the cam follower descends ):
