IMPROVEMENTS IN PLANING MACHINES
Year: 1875

page_text: LETTERS PATENT to Thomas Smith, of Liverpool, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN PLANING
MACHINES"
Sealed the 9th December 1875, and dated the 14th October 1875.
PROVISIONAL SPECIFICATION left by the said Thomas Smith at the
Office of the Commissioners of Patents, with his Petition, on
the 14th October 1875.
I, THOMAS SMITH, of Liverpool, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN PLANING MACHINES," to be as follows:-
This Invention relates to planing machines in which two horizontal
tables are employed, and in which the under table has a to-and-fro
motion given to it, and the upper table not only partakes of the to-and-
fro motion of the under table, but has also motion around a vertical
axis. The object is to truly and quickly plane radius links and like
curved surfaces.

page_text: Under the first part of my Invention I give the upper table an axial
motion by means of gearing or mechanism acting at or near to one or
both ends of the table; a toothed segmental rack and worm answers
well; change wheels or other means for decreasing or increasing the
speed may be used. The greater the speed of the axial motion in
proportion to the to-and-fro motion the smaller is the radius of the
curve planed.
Under the second part of my Invention I make use of what I call
compensating gear, that is to say, I employ in combination with the
mechanism described under the above first head apparatus or appliances
which will serve to retard or accelerate the axial motion of the upper
table. The object of the above compensating gear is to obtain any
desired speed of axial motion between the speeds given by change
wheels or like means, and so obtain any desired curve on the object
planed.
For the above purpose I fit the worm mentioned under the above first
head in a bush so that it shall be free to move longitudinally, and I
govern the longitudinal motion by means of an inclined plane and
friction wheels by means of a grooved cam or in other convenient
manner. A spring may be used to keep the worm wheel in position.
It will be obvious that the above described Invention may be easily
adapted and applied to planing machines already in existence, and that
for curves of large radius the compensating gear may be used without
the change wheel gear being employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said Thomas Smith in the Great Seal Patent Office
on the 13th April 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SMITH, of Liverpool, in the County of Lancaster, Engineer, send
greeting.
.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of October, in the
year of our Lord One thousand eight hundred and seventy-five, in;
8

page_text: Under the second part the worm shaft k is supported in bearings, l',
and is capable of a longitudinal motion. To the shaft bearing lis
attached the plane m by the joint n; the angle of the surface of the
plane m to the shaft k is adjusted by means of the set screws o. The
end of the shaft k projects through the plane m, and is provided at its
outer end with the roller p, which works on the plane m. The roller p
is kept up to the plane m by means of the spring q. It will be obvious
that during the revolution of the shaft k the roller p will travel round
the plane m, and that according to the inclination of the plane so will
be the longitudinal motion of the shaft k. The change wheels and the
inclination of the plane are so adjusted that the axial motion given to
the upper table produces the desired curve. It will be obvious that a
grooved cam or similar device may be employed in place of the inclined
plane and roller above described.
When it is desired to employ more than a semi-revolution of the
wheel during the to-and-fro motion the inclined plane may be made in
the form of a screw or like surface.
Having now described the nature of the said Invention and par-
ticularized the same in such manner that others will be enabled to
carry my improvements into effect, I claim,-
Under the first part the arrangement and combination of parts sub-
stantially as and for the purposes set forth.
Under the second part the compensating gear substantially as and
for the purposes set forth.
In witness whereof, I, the said Thomas Smith, have hereunto set
my hand and seal, the Eleventh day of April, in the year of our
Lord One thousand eight hundred and seventy-six.
J. JOHNSON,
Patent Office,
Clayton Square,
Liverpool.
THOMAS SMITH. (L.S.)