ys been a driving
gear and one or two toothed racks. In Koenig's original movement, the
driving gear on the end of a rising and falling shaft ran on top of a
rack attached to the bottom of the bed in order to drive the bed in
one direction, and then descending around the end of the rack ran in
the bottom to the same rack to drive the bed in the other direction
and ascending at the other end to repeat the movement. This, as
already stated, has proven a very efficient mechanism and is employed,
with improvements, by some of the press manufacturers of the present
time.

In a pamphlet entitled "A Short History of the Printing Press" (New
York, 1902), by Robert Hoe, the writer describes a method of reversing
the bed. Although somewhat technical, it seems desirable to quote him
as follows: "As early as 1847, Hoe & Co. patented an entirely new
bed-driving mechanism. To a hanger fixed on the lower side of the bed
were attached two racks facing each other, but not in the same
vertical plane, and separated by a distance equal to the diameter of
the driving wheel, which was on a horizontal shaft and movable
sideways so as to engage in either one or other of the racks. By this
means, a uniform movement was obtained in each direction. The reversal
of the bed was accomplished by a roller at either end of the bed
entering a recess in a disc on the driving shaft, which in a
half-revolution brought the bed to a stop and started it in the
opposite direction. This involved a new principle; a crank action
operating directly upon the bed from a shaft having a fixed centre,
and within recent years modifications of this patent have been
successfully employed to drive the type-bed at a high velocity and
reverse it without a shock or vibration."

This invention appears to have been the forerunner of the more recent
improvements in bed motions. A notable one is that employed in the
Miehle presses, which have gained much celebrity, run at a high rate
of speed, and are used in many printing-offices in this and other
countries. The reversal of the bed movement is accomplished by a
so-called "true crank" movement and with an absence of jar and
vibration never before obtained in any other than the stop-cylinder
presses.

At the present time, the latest development in printing presses is Hoe
& Co.'s new two-revolution press, in which, also, the reversal of the
bed is accomplished by the true crank movement, but with an
improvement which brings it