Abstract: A jam-tolerant dual-redundant differential-summing actuator (20) includes a first driver (23) adapted to be rotated about a first axis (x1-x1) at a first surface speed; a second driver (26) adapted to be rotated about a second axis (x1-x1) at a second surface speed; a movable output member (21); and a linkage (24, 28, 31, 32, 33, 34, 40) connecting the first and second drivers to the output members such that the output member will be moved at a velocity that is substantially proportional to the average surface speed of the drivers.

Abstract: An oven includes a plurality of pairs of upper and lower spaced non-focused infrared heater panels. Product is conveyed between these panels to effect solder reflow. To increase heat transfer and to achieve temperature uniformity, air is forced through equally spaced holes drilled in the insulating block of one or more upper heating panels. To define an equal flow through these holes, a valve is placed below the air intake opening to define an annular opening between the panel casing and the valve. The valve has openings having an area which is matched to the annular area between the casing and the valve.