saw for sawing metals
Year: 1899

page_text: Date of Application, 24th Aug., 1899-Accepted, 11th Nov., 1899
I, WILHELM HARTMANN, of Fulda, Germany, do hereby declare the nature of
my invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:.
"
My invention relates to a new and improved "band saw for sawing metals'
and is constructed and operated as set forth in the following specification of
which the accompanying drawings form an inseparable part.
In the drawings in which similar letters refer throughout to similar parts,
Fig. 1 shows in side elevation my invention,
Fig. 2 is a sectional view thereof on line A-B of Fig. 1,
Fig. 3 is a plan view of Fig. 1.
Fig. 4, 5, 6 and 7 show modified forms of parts of the machine.
Heretofore band saw machines for sawing metals have been so constructed
that it was necessary to continuously advance the object being sawed against
the band saw. In lieu of band sawing machines, machines were therefore
generally employed having an oscillating or pendulum swung saw working upon
the object stationarily fixed. the latter forms alone being susceptible of opera-
tion without generating, a frictional resistance of such degree as to make the
machine unpractical. The fact, that until my invention the sawing machines
having the object stationarily fixed were preferably provided with an oscillating
or pendulum swung saw, is due to the cause that such alone were sufficiently
susceptible of continuously operating upon and freely and simultaneously there-
with advancing against the said object.
It is therefore with the elimination of such drawbacks that I have invented a
band saw machine in which the object to be sawed is stationarily secured while
the band saw proper receives a regular cutting motion and in addition therefo
and simultaneously therewith an automatic forward movement, the latter in all
parts where friction is produced acting in such a manner that straight movement
is avoided and exclusively rotating parts are sliding in their journals whereby
an extremely easy movement is obtained.
In the construction of my invention therefore, I employ any desired frame as C
which has transversely mounted therein three parallel main shafts g. p and p¹,
while fastened to the forward side of said frame are suitable brackets ¹ and w
forming additional bearings for the forward ends of the shafts aforesaid. These
bearings q, q, 72, 72 have preferably bearing balls therein so as to reduce the
friction in the axial movement of said shafts to a minimum, which latter have,
as will be seen, a spirally turning fore and rear motion.
Mounted on shaft q is a roller which with rollers c and el respectively mounted
on shafts and p carry the saw band a adapted to saw any object fixed on a
table or shelf adjacent thereto. Securely fastened to the frame C, projecting
rearwardly therefrom, is a shaft casing t in which is mounted an axle s carrying
at its rear end a pulleys and at its forward end a toothed wheel d having any
desired length, while mounted on shaft pl is a toothed wheel meshing with
wheel d aforesaid, and through which latter the shafts are given a rotary motion,
877

page_text: thereby operating the band saw a, and by which special construction of wheel d
its rotary movement can be imparted to wheel at whatever position the shaft p
many assume. Near the rear end of shaft g is a sleeve r having studs therein,
the latter in turn fitting in the prongs of a fork o' connected with a rod o suit-
ably mounted in bearings o² in the said frame and extending at right angles to
said shafts. To one end of said shaft o is connected a band n which passing over
suitably grooved wheels m, m' has on its outer end a weight n, which as the latter
descends throws arm of forward thereby imparting a forward pressure to said
shaft. But since the said shaft is rapidly rotating its motion forward loses
any direct forward movement and becomes a spiral or twisting action.
In order to transmit this spiral action to shafts p and I employ racks k
mounted on vertical axles i, i which latter are journalled in any suitable
supports connected with the frame of the machine. The side of the rack k
adjacent to shaft q, is provided with a forked arm having slots g formed therein,
and into which latter fit pins f also carried on sleever aforesaid. On the
adjoining sides of the racks k, are meshing toothed quadrants 7, 7 through which
connection as will clearly be seen the racks act together. The other is in turn
in connection by suitably forked arms with shafts and p¹, whence it will be
seen that any forward movement imparted to shaft q will be simultaneously
transmitted to the said latter shafts.
The operation and advantages of my invention will be clearly understood from
the foregoing description and accompanying drawings when taken in connection
with the following statement. Desiring to saw a piece of metal, the same is
secured to a suitable table or shelf and the machine thrown in gear, whence the
power imparted by pulleys to axle s drives wheel d, the latter in turn rotating
wheel on shaft p, which carrying roller c operates the band saw connected
therewith together with rollers and band their respective shafts. Simul-
taneously therewith however weight n continually draws band n¹ downwardly
thereby revolving rod o which latter through arm ol in connection with shaft q
and the latter through the racks k with their meshing quadrants impart to the
said shafts a steady forward pressure but which in place of developing a direct
forward movement thereto is converted through the combination of the inde-
pendent rotary motion aforesaid therewith into a spirally advancing forward
action, thereby eliminating any frictional resistance arising through a straight
movement of said shafts while rotating. By this adjustment the band saw is
continually advanced and held against the object without however causing any
heavy frictional resistance in the machine itself, by such advancement.
Fig. 4 shows a modification of the device for transmitting the rotation of
shaft o to the racks k. Instead of one lever o¹ two levers o¹ are secured to the
central portion of shaft o directly engaging at their upper ends with racks k. In
Fig. 5 a modification is shown, in which the forks h holding the band saw rollers
are secured to levers o and which latter in turn are operated by bar of connecting
the ends of the levers o¹. The levers o³ are pivotted on the axles i.
Fig. 6 & 7 show a modified form of a band saw roll 2 made of sheet iron, for
reducing weight and sliding on its shaft under the control of the spring resting
against collar and guided by pin c and slot 3. By this arrangement the
sensibility of the saw-blade a is still increased.
Having now particularly described and ascertained my said invention, and in
what manner the same is to be performed, I declare that what I claim is:-
1/ In a new and improved band saw the combination of a sawing band with
rotatable, spiral actuated means for operating and advancing said sawing
band substantially as described.
2/ In a new and improved band saw the combination of a sawing band with
certain distinctive mechanisms, each adapted to impart to their point of union a
distinctive force which uniting provides rotatable, spiral-actuated means for
operating and adjusting said band, substantially as described.

page_text: 3/ In a new and improved band saw the combination of a frame, ball bearings
therein, shafts mounted in said bearings rollers on said shafts, a sawing band on
said rollers and means in connection with said shafts adapted to give the latter a
rotatable, spiral actuating movement, substantially as described.
4/ In a new and improved band saw, the combination of a frame, ball bearing
journalled shafts therein, rollers on the forward ends of said shafts, a sawing
band on said roller, a pulley wheel in said frame, gearing connecting said wheel
and said shafts and a weight actuated rod in connection with said shafts, sub-
stantially as described.
5/ In a new and improved band saw, the combination of a frame, shafts
journalled therein rollers on said shafts, a sawing band on said rollers, a rod
suitably mounted in said frame, forked arm on said rod provided with slots in
the prongs of its fork, a sleeve on one of said shafts, studs on said sleeve entering
said slots, racks in connection with said frame, toothed quadrants on each of said
racks meshing together, other forked arms on said racks engaging said shafts, a
band connected with said rod, a weight on said the outer end of said band and
suitable mechanism for rotating said shafts substantially as described.
G/ In a new and improved band saw the combination of a saw-roll guided
longitudinally on its shaft, a spring around the axle, and a collar on the axle as
and for the purpose specified.
Dalth 10th
f August 1900