SMOOTHING ROLLS

215

doctors in most positions. It consists of a row of springs fixed to a rigid
holder, and these springs are slotted to take a flexible thin steel blade. It
will be easily understood that this flexible doctor blade readily accommodates
itself to any irregularities on the roll, and to variations in the position of the
roll—/.*., when paper is being led through at one end, and so tilting the roll
out of parallel with the doctor support.

In order that the blade may take up these distorted positions, it is obvious
that it must be capable of
moving sideways, as the distance
between the ends will be less in
these positions. The blade, being
only lightly held, can slide side-
ways to make up for these
distortions.

Being thin and of light con-
struction, the doctor rapidly
responds to differences of tem-
perature, such as the heat of
calender rolls, M.G. cylinders
and intermediate rolls. It keeps
the surface clean and polished
and in good condition.

The blades never need to be
filed and fitted and they last fairly
well, even on fast news machines.

The blade itself, when worn
out, is very easily replaced, only
a few minutes being required, in
place of the hours often neces-
sary with the older types of
doctor, which had to be filed
until they fitted approximately.

A new type of blade is being used with great success for keeping rolls clean.
Hiis is made of a bake&ed cotton substance which takes on a very keen edge,
and seems to be self-sharpcmng. It can be used on breast rolls, wire rolls, and
peas rolls, and fits more snugly to die roll than an iron doctor. It has many
advantages over wood and iraa, and is less likely to groove the surface
which it COOKS ia contact.

Calender &0&.—Most machines making E*S. papers have three sets
five rolls each- A very good machine finish may be got with these, but

Sy.-ViocatT PATENT FLECTLE DOCK* AWUBD
TO A BWAST ROLL