Improvements in Guards or Protecting Apparatus for Circular Saws or Analogous Tools.
Year: 1886

page_text: PROVISIONAL SPECIFICATION.
Improvements in Guards or Protecting Apparatus for Circular
Saws or Analogous Tools.
I, RALPH WILLOUGHBY of The Industrial Schools in the City of Newcastle
upon Tyne Superintendent of Industrial Schools do hereby declare the nature of
this Invention to be as follows:-
This Invention has for its object to provide simple and efficient means for
guarding or covering circular saws or analogous tools so as to prevent accidents
therewith the said means being such that that part of the saw or tool which is
situated above the bench on which the object to be operated upon slides is
completely covered and any article is prevented from accidentally coming into
contact with the saw or tool either when it is revolving or stationary whilst at the
same time it will allow any object that is intentionally pushed along such bench to
be properly operated upon by the saw or tool and after the operation is concluded
will return automatically to its normal position.
In an apparatus constructed according to my Invention a part which I will call
the hood is made to cover the top part of the saw or tool. The said hood is
supported by a rigid frame or support and it may be connected thereto by slots
and screw nuts to allow of adjustment of its height above the bench to suit the
general thickness of material required to be operated upon. To this hood portion
is connected what I will term the shield which is of sufficient height when resting
on the bench to conceal (preferably completely) that part of the saw or tool above
the bench which is not concealed by the aforesaid hood. The ends of the shield at
the entry side may be slightly curved on their under edge to facilitate the entry of
the material to be cut. The shield may consist of a double plate one on each side
of the saw or tool or it may consist of a plate on one side only of the saw or tool
leaving the other side protected by the ordinary fence or its equivalent.
The shield is hung from the hood portion by hangers or suspenders or equivalent
connections upon which the shield moves so that it will be raised when the material
to be operated upon is pressed against it and will thereafter fall back to its original
position when the material is withdrawn The shield may be provided with checks
or stops to come in contact with the hood portion to limit the motion of the shield
as desired.
J

page_text: When the operator moves the plank or material to be sawn or operated upon
along the bench it first comes into contact with the shield which it moves upon its
suspenders or the like so as to expose the operating part of the saw or tool and
allow the plank or material to pass along (under the shield and hood) to be operated
upon by the tool. When the operation is completed and the plank or material is
removed the shield returns automatically by its weight to its normal position for
protecting the saw or tool.
COMPLETE SPECIFICATION.
:
Improvements in Guards or Protecting Apparatus for Ciroular
Saws or Analogous Tools.
5.
I RALPH WILLOUGHBY of. The Industrial Schools in the City of Newcastle
upon Tyne Superintendent of Industrial Schools 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 to provide simple and efficient means for
guarding or covering circular saws or analogous tools so as to prevent accidents
therewith the said means being such that that part of the saw or tool which is
situated above the bench on which the object to be operated. upon slides is
completely covered and any article is prevented from accidentally coming into
contact with the saw or tool either when it is revolving or when it is stationary
whilst at the same time it will allow any object that is intentionally pushed along
such bench to be properly operated upon by the saw or tool and after the operation
is concluded will return automatically to its normal position.
'
I will describe my Invention with reference to the accompanying Drawings
Figure 1 of which is a side elevation of a circular saw bench fitted with my
improvements and figure 2 is a transverse section of the same. Figures 3 and 4
are perspective views of the upper portion of a bench shewing a modified arrange-
ment for supporting the guarding hood.
The saw or tool A is mounted on the spindle B and is rotated in the ordinary
manner,
1.
The top part of the saw or tool which projects above the table of the bench
is covered by a hood C which is supported by a rigid frame or support in any

page_text: convenient way from any suitable part of the bench or from the roof or ceiling
overhead or by any other available or suitable means so as to allow of adjustment
of the height of the hood above the bench to suit the material to be operated upon
for example it may be secured by the frame of the hood being extended as shewn
in Figure 1. in the bar D adjustable to the bench by the screw bolts E passing
through the slots F.
Figure 2 shews a section through the apparatus at a point (the centre) where
there is no bar. According to Figure 1 the bar admits of the passage under it of
material from the side of the bench and is suitable for cross cutting purposes.
A plank not too wide to pass under the bar can be cut to any length. The bolts
which pass through the slots in the bar are placed in the middle of each end of the
saw bench.
Or the hood C may be provided with slotted bars d by which it is adjustably
connected to a frame D rigidly attached to the saw bench as shewn in Figures 3
and 4. To the hood C is connected by hangers or suspenders G what I will term
a shield which may consist of two plates H arranged one on each side of the hood
and of the saw or tool and of sufficient height when resting on the bench to conceal
(preferably completely) that part of the saw or tool above the bench which is not
concealed by the aforesaid hood C or it may consist of a plate on one side only of
the saw or tool leaving the other side protected by the ordinary fence or its
equivalent. The ends of the shield at the entry side may be slightly curved at its
under edge as shewn at h to facilitate the entry beneath it of the material to be
operated upon by the tool.
The shield H is hung upon the hood by the hangers or suspenders G or equivalent
connections upon which the shield moves so that it will be raised when the material
to be operated upon is pressed against it as shewn in Figure 4 and will thereafter
fall back to its original position as shewn in Figures 1 and 3 when the material
is withdrawn The shield may be provided with a check or stop or checks or stops
for example as shown at h' to come in contact with the hood to limit the motion of
the shield as desired or the ends of the shield at the back may be returned as shewn
at H³ in figure 5 to constitute these stops or such a stop or check may be used
connecting both the plates H but in practice I find it best to have a stop on each
of the plates so that the plates are quite unconnected with each other as sometimes
only one plate is lifted by the material operated upon.
When the operator moves the plank or material to be sawn or operated upon
along the bench it first comes into contact with the shield H which it moves upon
its suspenders G or the like so as to expose the operating part of the saw or tool
and allow the plank or material to pass along (under the shield and hood) to be
operated upon by the tool When the operation is completed and the plank or
material is removed the shield returns automatically by its weight to its normal
position for protecting the saw or tool as herein before described whilst not
limiting myself to any particular material for the shield or the hood I prefer to
make them of thin sheet steel or perforated metal or wire gauze and in this case
the edges may be turned over wires as shewn with regard to the shield at x in
figure 5 as this construction gives a well rounded edge and lightness.
I do not limit myself to the use of the separate hood and shield as the hood may
be made with its sides of a sufficient depth to form the protection for the sides of
the saw or tool the ends being rounded so that the whole hood will be lifted by
the material being operated upon the shield being dispensed with as the lower part
of the hood takes its place or the equivalent of this may be employed by dispensing
with the hood and making the shield of a height equal to or about equal to that
of the saw or tool above the bench. The shield must then be hung with sufficient
rigidity to keep it from swaying against the saw. The hood or the shield when
employed according to these modifications may be hung or suspended on or from
any suitable supports or brackets as will be readily understood from the preceding
description. Where the friction to be overcome by raising the guarding device is
objectionally great it can be compensated by weights led over pullies or the like.

page_text: Having now particularly described and ascertained the nature of my said
Invention and the manner in which the same is to be performed I declare that
what I claim is
First. Guards or protecting apparatus for circular saws or analogous tools
consisting of a hood or shield so suspended upon or from guides or hangers or their
equivalents that the passage of the material to be operated upon lifts the said bood
or shield which after the material. is removed automatically returns to its normal
position substantially as herein before described.
Second. Guards or protecting apparatus for circular saws or analogous tools
consisting of a hood or cover situated over the upper part of the saw or tool and
a shield so arranged that it normally covers the acting portion of the saw or tool
but admits of the entry of the material to be operated upon and automatically
returns to its normal position when the operation of the Baw or tool has been
completed and the material is removed substantially as hereinbefore described and
illustrated by the accompanying drawings.
Third. In guards or protecting apparatus for circular saws or analogous tools the
combination of the hoods C shield H and hinged or centred hangers G substantially
as herein before described and illustrated by the accompanying Drawings.
Fourth. In combination with the subject matters of either of the preceding
claiming clauses a counterbalancing or compensating weight or its equivalent
substantially as and for the purpose hereinbefore described.