IMPROVEMENTS IN APPARATUS TO BE USED WITH CIRCULAR SAWS FOR PREVENTING ACCIDENTS IN, USING SUCH SAWS
Year: 1882

page_text: CL
PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office of
the Commissioners of Patents on the 8th December 1882. A communication
to him from abroad by Adolph Ignace Alfred Marie Trincano a person residing
at Paris in the Republic of France
F
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman, "IMPROVEMENTS IN APPARATUS TO BE USED WITH CIRCULAR SAWS
FOR PREVENTING ACCIDENTS IN, USING SUCH SAWS" a communication to me from
abroad by Adolph Ignace Alfred Marie Trincano a person residing at Paris, in the
Republic of France
This Invention relates to apparatus for preventing accidents to Workmen
engaged in feeding circular saws. The improved apparatus.consists essentially of a
guard in the form of a slotted bar or lever suspended from overhead supports and
capable of moving in various directions in a vertical plane and also provided with
a device for effecting the advance of the wood when finishing the cut. whereby the
necessity for the workman to touch the wood with his hands at this. dangerous part
of the operation is obviated This apparatus is capable of being adjusted according
to the diameter of the saw and the description or dimensions of the wood to be
cut. When the saw is not cutting the guard covers the teeth at the front side of
the saw and when the saw is at work the guard covers those teeth which are not
actually engaged in the wood. This guard also steadies the wood and prevents it
from being accidentally displaced and allows the progress of the saw. cut to be
watched without interfering with the cutting action or with the inspection of the
work as a clear space is left all around the saw admitting of the employment of a
suitable guide or f
fence
The apparatus is suspended above the table and in front of the saw and comprises
a stationary part rigidly connected to the beams overhead an adjustable part that
is capable of being removed or changed according to the size of the saw but is
stationary during the sawing operation and a part that is worked or manipulated
whilst the wood is being cut and comprising a carrier with a shoe a forked or slotted
lever and an oscillating lever worked by a treadle as hereinbefore described.
D
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page_text: The permanently fixed part of the apparatus is composed of two plates or
supports firmly connected to the roof or to beams overhead and provided with
horizontal slots for the reception of the adjustable part.
The adjustable or exchangeable part consists of a pair of slotted plates connected
together by cross bars and supported by bolts and clamps engaging with the
horizontal slots herein before referred to. These adjustable slotted plates are made
of different sizes corresponding to the diameters of the saws and the plates of each
pair are provided with a vertical slot which guides a carrier and with a curved
slot in the form of a segment of a circle in which works a slider connected to a
nose or adjustable stop on the guard hereinafter described.
The part that is manipulated during the sawing operation is composed of the
carrier herein before referred to which. is constructed with two uprights connected
by two cross bars, the upper cross bar being provided with a hook by which the
carrier is suspended. This carrier is provided with two small rollers working in the
vertical slots in the adjustable slotted plates and at its lower part presents two
shoes carrying two large and slightly conical rollers which facilitate the passage of
the carrier over the wood that is being sawn the shoes resting upon the wood on
starting. On the carrier are arms or levers hinged to arms carried by a cross bar
acting as a stop and connected to the slider guided in the curved slot in the
adjustable plates. Angular plates are provided on the shoes for the purpose of
steadying and facilitating the advance of the wood. Two bent rods are connected
at one end to a swivelling block at the lower part of the carrier being adjustable
longitudinally in the said block by means of set nuts and are jointed at the other
end to a forked lever and to a curved slotted bar which forms the guard proper.
This slotted bar is provided with a slot at its rear end in which is secured the nose
or adjustable stop herein before referred to which serves to maintain the forked
lever constantly at a suitable distance from the teeth of the saw and keeping it at
this distance when the carrier is raised-This bar acts as a guard and is provided
accordingly with a second slot or opening through which the path of the saw can
'be observed.
The forked lever jointed to the end of the guard is provided with a handle and
presents a fork the legs of which pass on opposite sides of the saw.
In order to prevent the metal of the fork from touching the saw in case of too
much force being applied to the lever the legs of the fork are covered with hard
wood at the part facing the saw which wood can be readily renewed when
necessary.
An overhead lever provided with a suitable counterweight and connected to the
carrier by the hook hereinbefore referred to enables the workman to lift the carrier
with facility by means of a treadle to the extent requisite corresponding to the size
of the piece of wood to be presented to the saw The stroke of the overhead lever
is so adjusted that it raises the carrier to such an extent that the under side of the
latter is level with the underside of the stationary slotted plates or supports and
thus leaves the table clear for changing the discs or sharpening the saws and
performing other operations in which the guard is not required.
When working with wood less than about three inches in thickness the conical
rollers may be brought down on to the table when the wood is removed-In this
case the adjustable slotted plates are lowered to the holes corresponding to this
height in the part held by the clamps, the bent rods' connected to the guard-are
shortened by screwing up the nuts on thin screwed ends and the nose or stop on the
guard is shifted towards the left
:
In working with this apparatus the workman first places the wood upon the
table and then raises the carrier by pressing the treadle with his foot until the
wood can be introduced underneath the shoes he then places the forked lever upon
the wood and commences to feed the latter forward using the treadle occasionally to
assist in getting over the difficult parts in the case of knotty wood or wood of
irregular shape When the wood has advanced to a point where the forked lever
can be brought into action which can be ascertained by means of a mark on the

page_text: table he ceases to push forward the wood by hand the end of the wood being now
say about four or six inches from the teeth of the saw and by drawing the handle
of the lever backwards and downwards he finishes the cut without touching the
wood. When the handle of the lever has been turned down on to the table, the
guard is thereby brought into such a position as to cover the front part of the saw
and thus render it impossible for the workman to bring his hands in contact with
the teeth.