Improvements in Band Saws.
Year: 1893

page_text: Date of Application, 2nd May, 1893
Complete Specification Left, 31st Jan., 1894-Accepted, 3rd Mar., 1894
Improvements in Band Saws.
I, LARS HENRIK FORNANDER, of Söderhamn, in the Kingdom of Sweden,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to band-saws.
When sawing wood it is very important to reduce the waste as much as possible.
It has therefore recently been the practice to employ for this purpose a combination
of band-saws as they cut away less dust than frame-saws. Economy of time is also
of a great importance and endeavours have therefore been made to construct saws
in which the distance between the cutting blades can be quickly altered.
According to my invention I employ several blades running over their respective
driving and straining wheels arranged side by side, the saw-blades being arranged
in pairs opposite one another on each side of the block to be sawn in such a way
that the spaces between the cutting parts of the bands can, even where as many
bands are used as are required to saw a block in one operation, be altered or
adjusted without stopping the saw.
The driving and straining wheels are journalled in separate frames, adapted to be
moved in guides in the supporting frame of the saw by means of a lever and pinions
located at each end of the beams and having each two shafts provided with two
chain pulleys between which and the frames pass chains in such a way that, when
the two shafts are moving towards each other, each alternate pair of the frames will
move in one direction, while the other pairs will move in the opposite direction; one
of the frames in each pair takes along the other.
The different band-saws will thus be easily accessible for repairs and alterations, as
for instance, when changing the blades. When the frames are required to be moved
with the view of regulating the dimensions of the boards or deals to be cut, I
preferably effect this by means of a lever connected each frame. The lever is
pivotted at one end of a rod which at the other end is pivotted in the frame.
In the table and in front of each frame is placed a rail having openings in which
engages the end of the lever so as to form a fulcrum when moving the frame.
The bands are strained by means of levers provided with weights, such levers
actuating the bearings of the straining wheels, which bearings slide in the frames.
The distance between the driving and the straining wheels is so short that no guide
rollers are required to prevent the cutting parts of the band from swinging.
The band-saws are driven by two shafts, one of which is the main shaft and
drives the other.
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COMPLETE SPECIFICATION.
Improvements in Band Saws.
0 I, LARS HENRIK FORNANDER, of Söderhamn, in the Kingdom of Sweden,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :—

page_text: When sawing wood it is very important to reduce the waste as much as possible.
It has therefore recently been the practice to employ for this purpose a combination
of band-saws as they cut away less dust than frame-saws. Economy of time is also
of a great importance and endeavours have therefore been made to construct saws
in which the distance between the cutting blades can be quickly altered.
According to my invention I employ several blades running over their respective
driving and straining wheels arranged side by side, the saw-blades being arranged
in pairs opposite one another on each side of the log or block to be sawn in such a
way that the spaces between the cutting parts of the bands can, even where as
many bands are used as are required to saw a block in one operation, be altered
or adjusted without stopping the saw.
In the accompanying drawing,
Figure 1 is an end elevation partly in section of a band-saw machine constructed
according to my invention.
Figure 2 is a side elevation partly in section; and,
Figure 3 is a plan of the same.
The saw-bands run over the straining wheels A C and driving wheels B D and
are arranged in pairs opposite one another on each side of the axis of the log or
block to be sawn.
The driving and straining wheels (which for example may be five in number on
each side as shewn) are journalled in separate frames H adapted to be moved in
guides in the beams K connected together and constituting the supporting frame of
the saw, by means of a crank handle and pinions L located at each end of the beams
and having each two shafts N and O provided with chain pulleys M between which
and the frames pass chains in such a way that, when the two shafts are moving
towards each other, each alternate pair of the frames will move in one direction,
while the other pairs will move in the opposite direction one of the frames in each
pair drawing along the other.
The different band-saws will thus be easily accessible for repairs and alterations,
as for instance, when changing the blades. When the frames are required to be
moved with the view of regulating the dimensions of the boards or deals to be cut, I
preferably effect this by means of a lever Q connected with each frame. The lever
is pivotted at one end of a rod R which at the other end is pivotted in the frame.
In the table and in front of each frame is placed a rail S having openings T in
which engages the end of the lever so as to form a fulcrum when moving the frame,
as will be readily understood by reference to the drawing.
The bands are strained by means of levers V provided with weights U, such
levers actuating the bearings of the straining wheels A, C, which bearings slide in
the frames. The distance between the driving and the straining wheels is so
short that no guide rollers are required to prevent the cutting parts of the band
from swinging.
The band-saws are driven by two shafts X, X, one of which is the main shaft
and drives the other.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
+
1. In band-saws having several blades running over their respective driving and
straining wheels arranged side by side and which saw-blades are arranged in pairs
opposite one another on each side of the axis of the log or block to be sawn, the
arrangement of mechanism in which the blades on one side, guided without any
adjusting plates or discs, are with their driving and straining wheels secured in
frames movable in guides with relation to the opposite frames on the other side of
the axis of the log or block to be sawn, so as to allow the distance between the
cutting parts of the bands to be changed or adjusted by moving the frames even
without stopping the saw, substantially as herein before described.

page_text: 2. The improved band saw hereinbefore described and illustrated in the
accompanying drawing.
Dated the 31st day of January 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.