Improvements in or relating to Guards or other Protective Arrangements for Mechanical Saws.
Year: 1899

page_text: Improvements in or relating to Guards or other Protective
Arrangements for Mechanical Saws.
A communication by PAUL LAVAUR, of 85, Boulevard de Strasbourg, Paris, in
the Republic of France.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester,
both in the County of Lancaster, 118, New Street, Birmingham, in the County
of Warwick, and 322, High Holborn, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object an improved protective arrangement for
mechanical saws and is intended to protect the hands of the workmen from
accidents which might arise during the working of the saw.
My invention consists of a sheath or guard formed of two parts which are so
arranged as to entirely cover the part of the saw which projects above the bench
on which the saw is mounted and revolves.
The parts of the sheath or guard are pivoted together at their upper ends and
the common axis on which they are pivoted is fixed in a frame capable of sliding
vertically so that it may be raised or lowered on a support or bracket placed on
the saw bench. This support in certain cases in order to leave the surfaces of
the bench free, may be replaced by a hanging column fixed to the rafters of
the workshop. The parts of the sheath or guard which is placed at the work-
man's end of the bench may, by a peculiar arrangement which I shall herein-
after describe, be raised by means of a cord or rope attached to it by one of its
ends, said cord then passing over pulleys suitably situated and arranged, and
arm of a lever. This lever is
finally being attached by its other end to an
pivoted at its centre on a support or bracket placed beneath the saw bench. On
said support a star shaped piece having three arms is mounted which is arranged
in such a way that the ends of its arms in the movement of rotation of the said
star, project to a certain extent above the saw bench.
Each of the arms of the star shaped piece carries a roller in a state of repose,
two of these rollers bear against a lever located beneath the bench, the end of
which is formed of a straight part preceded by a curved part.
The half sheath or guard has on one of its sides a V-shaped lever provided,
at the top of the angle which it forms, with an elongated opening which enables
it to be displaced obliquely upwards and according to the direction of its arm
on a spindle fixed in a frame which is permanently attached to said half sheath
or guard. The arm of the V-shaped lever engages in a position of repose with
a stud in a notch formed on the circumferential part of the half sheath or guard.
The other arm of said lever bears at its extremity, placed outside the half sheath
or guard, a curved mask which bears with its lower edge on the saw bench.

page_text: The improved arrangement for protecting saws will be readily understood
from the following description of the mode of working same. When the work-
man places a piece of wood on the saw bench in the direction of the travel of
the saw, the end of this piece of wood encounters the end of one of the arms
of the star shaped piece which forces the latter to turn and to act with one of its
rollers on one of the ends of the lever located beneath the saw bench in order
to cause the latter to pivot.
The pivoting movement of the lever has for effect, in consequence of raising
the opposite end of said lever, to pull the cord or rope and raise the half sheath
or guard, the V-shaped lever placed on this half sheath being engaged by its
arm with the latter which is raised with it to a sufficient height to allow the
piece of wood, whatever its thickness may be, to pass beneath, and be acted on
by the saw.
The extent of the rotary movement of the star shaped piece is such that the
roller which is in contact with the extremity of the lever is displaced on the
straight part of said lever to a sufficient extent to enable the said roller, at the
end of the movement of rotation of the star shaped piece, to escape from said
straight part and drop into the curved part of the lever, which has for its effect,
aided by the weight of the half sheath or guard, to cause said lever to be raised.
which in its turn acts on. said curved part to cause the movement of rotation of
the star shaped piece to continue, so that its following arm is presented under
the piece of wood and emerges above the saw bench when the piece of wood is
almost entirely sawn.
Immediately the piece of wood has been sawn to a sufficient length to bear
with its end on the lower angle of the V-shaped lever, the latter being raised
will move in the direction of its arm which will release it from the notch, which
retains it, in the half sheath or guard.
When the wood has been almost completely sawn, and its rear end has
reached the mask of said V-shaped lever, this mask will fall behind the piece
of wood and prevent in an absolutely automatic manner the hands of the work-
man from coming in contact with the saw.
It is only necessary then to entirely release the piece of wood by pulling it
from the front, the half sheath or guard will then drop in turn, and the end of
the V-shaped lever will re-engage in the notch for the next operation.
It is evident that the arrangement' hereinbefore described in connection with
a circular saw might, with certain modifications of detail, be applied to band
saws, jack saws and the like, and in general to all saws, the wood for which is
to be guided by hand.
Dated this 28th dow of Tune 1800
A communication by PAUL LAVAUR. of 85, Boulevard de Strasbourg, Paris, in 45
the Republic of France.

page_text: both in the County of Lancaster, 118, New Street, Birmingham, in the County
of Warwick, and 322, High Holborn, in the County of Middlesex, Civil
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:-
-
This invention has for its' object an improved protective arrangement for
mechanical saws and is intended to protect the hands of the workmen from
accidents which might arise during the working of the saw.
The invention will now be described with reference to the accompanying
drawings in which,
Fig. 1 is a side elevation of a saw bench provided with this protective
arrangement, and
Fig. 2 is an end view of the same.
The invention consists of a sheath or guard formed of two parts a b which are
so arranged as to entirely cover the part of the saw which projects above the
bench on which the saw is mounted and revolves.
The parts
a and b of the sheath or guard are pivoted together at their upper
ends and the common axis e on which they are pivoted is fixed in a frame f
capable of sliding vertically so that may be raised or lowered on a support or
bracket placed on the saw bench d. This support in certain cases in order to
leave the surfaces of the bench free, may be replaced by a hanging column
fixed to the rafters of the workshop. The part a of the sheath or guard which
is placed at the workman's end of the bench may, by a peculiar arrangement,
which will be hereinafter described. be raised by means of a cord or rope
attached to it by one of its ends, said cord being connected with a lever i h
pivoted on a support and then passing over pulleys suitably situated and
arranged, and finally being attached by its other end to an arm of a lever j.
It is of course understood that the method of transmission by the intermediary
of the lever is merely mentioned as an example and instead thereof support
pulleys over which the cord passes may be employed. This lever is pivoted
at its centre on a support or bracket placed beneath the saw bencli d. On said
support a star shaped piece / having three arms is mounted which is arranged
in such a way that the ends of its arms in the movement of rotation of the
said star, project to a certain extent above the saw bench d, as shown in Fig. 1.
Each of the arms of the star shaped piece carries a roller m. In a state of
repose two of these rollers bear against the lever j, the end of which is formed
of a straight part n preceded by a curved part o.
The half sheath or guard a has on one of its sides a V-shaped lever ? pro-
vided at the top of the angle which it forms, with an elongated opening
which enables it to be displaced obliquely upwards and according to the direction
of its arm on a spindle fixed in a frames which is permanently attached to
said half sheath or guard a. The arm of the V-shaped lever engages in a
position of repose with a stud in a notch formed on the circumferential part
of the half sheath or guard a. The other arm of said lever bears at its extremity,
placed outside the half sheath or guard a, a curved mask which bears with its
lower edge on the saw bench .
The improved arrangement for protecting saws will be readily understood
from the following description of the mode of working same. When the work-
man places a piece of wood on the saw bench in the direction of the travel of
the saw, the end of this piece of wood encounters the end of one of the arms of
the star shaped piece 7 (Fig. 1) which forces the latter to turn in the direction
indicated by the arrow and to act with one of its rollers m on one of the ends of
the lever located beneath the saw bench in order to cause the latter to pivot.
This pivoting movement of the lever has for effect, in consequence of raising
the opposite end of said lever j. to pull the cord or rope and raise the half sheath
or guard a. the V-shaped lever / placed on this half sheath being engaged by

page_text: its arm with the latter which is raised with it to a sufficient height to allow
the piece of wood, whatever its thickness may be, to pass beneath, and be acted
on by the saw.
The extent of the rotary movement of the star shaped piece 7 is such that the
roller m which is in contact with the extremity of the lever is displaced on the
straight part n of said lever to a sufficient extent to enable the said roller, at the
end of the movement of rotation of the star shaped piece, to escape from said
straight part and drop into the curved part of the lever, which has for its
effect, aided by the weight of the half sheath or guarda, to cause said lever j to
be raised, which in its turn acts on said curved part to cause the movement
of rotation of the star shaped piece to continue, so that its following arm is
presented under the piece of wood and emerges above the saw bench when
the piece of wood is almost entirely sawn.
Immediately the, piece of wood has been sawn to a sufficient length to bear
with its end on the lower angle of the V-shaped lever p, the latter being raised-
will move in the direction of its arm r which will release it from the notch,
which retains it, in the half sheath or guard a.
When the wood has been almost completely sawn, and its rear end has
reached the mask of said V-shaped lever p, this mask will fall behind the
piece of wood and prevent in an absolutely automatic manner the hands of the
workman from coming in contact with the saw.
It is only necessary then to entirely release the piece of wood by pulling it
from the front, the half sheath or guard a will then drop in turn, and the end r
of the V-shaped lever will re-engage in the notch for the next operation.
It is evident that the arrangement herein before described in connection with a
circular saw might with certain modifications of detail be applied to band saws,
jack saws and the like, and in general to all saws, the wood for which is to be
guided by hand,
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :---
1. A protective arrangement for mechanical saws intended to automatically
.prevent the workman from moving his hands against the moving part, said
arrangement being composed of a protective sheath or guard in two parts pivoted
together, the front half guard which is connected by a cord to an operating
lever being adapted to be raised by the action of the piece of wood which is to
be sawn encountering on the saw bench a roller mounted on an arm of a star
shaped piece pivoting on a horizontal axis and in contact by means of two
other arms with a lever for operating the front half sheath, the piece of wood
thus causing the said star shaped piece to turn in such a way as to sufficiently
open the protective sheath, substantially as described.
2. In a protective device such as described, the arrangement of operating lever
consisting of a curved piece following a straight piece in such a way that when
the roller in contact with the lever has passed the straight part, the curved part
enables the operating lever to rise under the action of the weight of the front
half sheath the moment the piece of wood becomes free on the saw bench, the
whole apparatus thus returning automatically to the initial position as soon as
the sawing operation is terminated, substantially as described.
3. In a protective device such as described the arrangement on the front
part of the sheath of a V-shaped lever having at the apex of its angle an elon-
gated slot in which the axis of rotation passes, enabling it to be displaced
upwards in the direction of one of its arms, the latter being terminated by a stud
which engages in a notch formed on the front half-sheath, and the other having
a curved mask as that the piece of wood to be sawn encounters the lower angle of
the V-shaped piece, causes it to rise and thus releases the stud from its notch
and causes the mask to drop, which then closes the passage to the piece of wood

page_text: when the latter is at its height, the whole returning to its position by the action
of the weight when the front half sheath drops after the passage of the entire
piece of wood, substantially as described.
1
1711
1000