IMPROVEMENTS IN MACHINERY FOR SAWING WOOD
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Håkan Steffanson at the Office
of the Commissioners of Patents, with his Petition, on the 6th
October 1868.
I, HÅKAN STEFFANSON, of Gefleborgs Lån, in the Kingdom of Sweden,
but at present residing at Hans Place, Brompton, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN MACHINERY FOR SAWING WOOD," to be as follows:-
The object of this Invention is to equalise the motion of saw frames
by checking or counteracting the momentum of the frame and using
the power thus acquired in driving the frame in the opposite direction.
By so doing I am enabled to avoid the shaking and strain on the
connected
bearings of the frame and on those of the machinery
therewith. This object may be effected in various ways, all however
dependent on the same principle of action, which may be described
as consisting in providing an elastic cushion to receive the shock of
the cross head of the reciprocating saw frame at each end of the stroke.
This elastic cushion may be formed either of a body of air, steam, or gas
contained in a cylinder or cylinders, or india-rubber or metallic springs
may be employed in place thereof. The cylinder to contain the elastic

page_text: fluid may be either double or single acting, and it may be placed either
above or below the frame. If desired two or more cylinders may be used,
and these may if necessary be placed above and below, and one or more
cylinders may be placed on each side as well as above and below. In
the working of all or any of these cylinders air, steam, or any elastic
gas may be used.
A convenient arrangement of the apparatus would be produced by
employing the sides of the frame, as the pistons and the slide bars
would act as the cylinders in which the pistons should work, it being
then only necessary to have slide blocks at each end of each side of the
frame working in slide bars for its more effectual support. In this
arrangement the apparatus might be either single or double acting.
Another convenient arrangement would be produced by placing one of
four cylinders at each end of the two sides of the frame so that with
the addition of a piston to each corner of the moveable frame the four
pistons and cylinders would constitute the slide blocks and bars in which
the frame should work. In this arrangement the apparatus might
be either single or double acting.
In all the arrangements mentioned the cylinder instead of the piston
could be secured or adapted to the moveable frame, as may be found
most convenient under different circumstances or at the will of the
mechanic.
In all cases where single-action cylinders are used instead of the
piston a plunger might be employed, or, in other words, a piston whose
diameter throughout the whole of that part of it which enters the
cylinder should be the same as the inside diameter of the cylinder, as is
the case in many common air pumps.
Instead of the cylinder and
piston or plunger, steel springs or buffers with steel springs or india-
rubber or other elastic packing might be used.
If desired the piston may be made to create a partial vacuum in the
cylinder on the down or up stroke, so that the tendency of the air
contained in the cylinder to resume its normal density will have the
effect of assisting in lifting the saw frame.