Abstract: A computing device retrieves a stabilized weight and a weight-based item count for one or more items to be purchased. Responsive to retrieving the stabilized weight, the computing device retrieves an image-based item count and an expected weight based on the image-based item count for the one or more items to be purchased. The computing device selects between authorizing and blocking checkout of the one or more items based on the weight-based item count, the image-based item count, the stabilized weight, and the expected weight.

Abstract: A rotary-to-linear converter for use with a valve actuation device having a linear reciprocating cam shaft having longitudinally extending cam grooves that are engaged by captive cam followers which oscillate up and down in response to sideways reciprocation of the camshaft for actuating intake or exhaust valves of internal combustion engines or other devices employing reciprocating pistons and valves. The camshaft is caused to reciprocate by a rotary linear converter of the “yankee” type composed of double helix channel at the extreme end of the camshaft and a rotary drive collar having two sets of diametrically opposed guide members. The guide members comprise dogs which are rotatably engaged with the drive collar and slidably engaged with the double helix channel of the cam shaft.

Abstract: A valve activation device having a linear reciprocating cam shaft having longitudinally extending cam grooves that are engaged by captive cam followers which oscillate up and down in response to sideways reciprocation of the camshaft for activating intake or exhaust valves of internal combustion engines or other devices employing reciprocating pistons and valves. The camshaft is caused to reciprocate by a rotary linear converter of the "yankee" type composed of double helix channel at the extreme end of the camshaft and a rotary collar having two sets of diametrically opposed guide members.