Improvements in or relating to Guards and Riving Knives for Use with Circular Saws.
Year: 1899

page_text: Date of Application, 7th Feb., 1899
Complete Specification Left, 4th Oct., 1899-Accepted. 25th Nov.. 1899
PROVISIONAL SPECIFICATION.
Improvements in or relating to Guards and Riving Knives for Use
with Circular Saws.
We, JOHN EDWARD WELSBY, of 79, Kent Road, Sawyer, and JAMES ROBERT
WARD, of 28, Norfolk Lane, Engineer, both of Sheffield, in the County of York,
do hereby declare the nature of this invention to be as follows:-
This invention relates to guards and riving knives for use with circular saws
and has for its object to construct a combined guard and riving knife the
former to lie over part of the circular saw and the latter to extend the wood
after being cut so as to give clearance for the saw.
According to this invention a plate is attached by flanges formed on one
or both sides of one edge to the under side of the saw bed so that the plate
passes upwards through the opening in the bed, in which the saw rotates, and
projects above the bed at the back of the saw. This plate constitutes the
riving knife and is so shaped and situated that the wood on leaving the saw
will be opened out, preventing binding of the saw.
The knife is placed as close as possible to the periphery of the saw and by
reason of its position also acts as a guard or protector thereto, being preferably
curved forward somewhat over the saw. The guard proper is provided with
an extension which is adjustably attached to the riving knife and to a projec-
tion at the back of the latter. This attachment is by means of bolts which
pass through slots in one or both parts, an arrangement which allows the angle
of the guard to be varied.
The extension at the back of the guard may conveniently comprise two strips
which lie on either side of the riving knife and projection to which they are
attached.
Supplementary plates or portions may be hinged or otherwise attached to
the guard so as to provide additional protection.
The guard can be thrown back when desired to allow access to the saw for
sharpening or other purposes.
It will be understood that the shape of the parts, the method of attachment
and other similar details may be varied to suit requirements.
Dated this 7th day of February 1899.
BOULT & WADE,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Guards and Riving Knives for Use
with Circular Saws.
We, JoHN EDWARD WELSBY, of 79, Kent Road, Sawyer, and JAMES ROBERT
WARD, of 28, Norfolk Lane, Engineer, both of Sheffield, in the County of York,
Improvements in or relating to Guards and Riving Knives for Use
with Circular Saws.
We, JOHN EDWARD WELSBY, of 79, Kent Road, Sawyer, and JAMES ROBERT
WARD, of 28, Norfolk Lane, Engineer, both of Sheffield, in the County of York,

page_text: 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 relates to guards and riving knives for use with circular saws
and has for its object to construct a combined guard and riving knife the
former to lie over part of the circular saw and the latter to extend the wood
after being cut so as to give clearance for the saw.
According to this invention a plate is attached by flanges formed on one
or both sides of one edge to the under side of the saw beu so that the plate
passes upwards through the opening in the bed, in which the saw rotates, and
projects above the bed at the back of the saw. This plate constitutes the
riving knife and is so shaped and situated that the wood on leaving the saw
will be opened out, preventing binding of the saw.
The knife is placed as close as possible to the periphery of the saw and by
reason of its position also acts as a guard or protector thereto, being preferably
curved forward somewhat over the saw. The guard proper is provided with
an extension which is adjustably attached to the riving knife and to a projec-
tion at the back of the latter." This attachment is by means of bolts which
pass through slots in one or both parts, an arrangement which allows the angle
of the guard to be varied.
The extension at the back of the guard may conveniently comprise two strips
which lie on either side of the riving knife and projection to which they are
attached.
Supplementary plates or portions may be hinged or otherwise attached to
the guard so as to provide additional protection.
The guard can be thrown back when desired to allow access to the saw for
sharpening or other purposes.
It will be understood that the shape of the parts, the method of attachment
and other similar details may be varied to suit requirements.
In the accompanying drawings:-
Figure 1 is a side elevation of the improved combined guard and riving
knife,
Figure 2 is a plan of the same, and
Figure 3 is an underside view.
Like letters indicate like parts throughout the drawings.
In applying the invention to an ordinary saw bench A having the usual
slot B, in which the saw rotates, we pass through this slot a plate C having one
or more flanges 1) of suitable shape. In the accompanying drawings the
device is represented as having a single flange D, which is fixed to the under
part of the bench by bolts D in such a way that the plate C lies in line with
the circular saw E. The part C₁ of the plate C which lies nearest to the saw
is bevelled so as to constitute a riving knife.
!
In the plate C are formed several holes C2 adapted to receive bolts or thumb
screws C, which hold the guard in place. The latter is preferably constructed
of two plates F, F, suitably shaped and of such a length that they partially
cover the upper part of the saw E, a metallic strip F2 being placed between
the plates and F¹ over the saw. Packing pieces, F3, F4, formed of wood,
or other suitable material, are fastened to the plates F, F¹ so as to strengthen
them and act as distance pieces. Upon these pieces, 13, F4, are fastened in some
suitable manner guiding strips F5, F6, which serve to obviate the vibration of
the saw.
A distance piece is also employed in the position shown in the
drawings, the plates F, F, being further pinned or fastened together as found
desirable. A slot G is cut through the plates F, F, and the packing pieces F3, F4,
the length of this slot varying in accordance with the length of the riving
plate and the diameter of the saw. The plates F, F lie on either side of the
plate C, and are secured thereto by bolts or thumb screws C3 which pass through
the slot G and through the holes C³ in the plate C.

page_text: One or more supplementary plates such as H may be hinged, as at H¹, or
otherwise fastened to the front part of the guard so as to form an extension
of the latter, the extension plate being hinged, as shown in the drawings, and
may be, when required, drawn back, as indicated by the dotted line H2 in
Figure 1.
If desired slots may be formed in the flange or flanges D of the plate C, so
as to allow the position of the latter to be adjusted.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is:-
1. The combination with a riving knife for use with circular saws of a guard
adjustably attached to the riving knife, substantially as described.
2. The combination with a riving knife, such as C, C, of a guard such as F, FI
adjustably connected to the riving knife and provided with an extension such
as H, substantially as described.
:
3. The complete guard and riving knife substantially as described or illus-
trated in the accompanying drawings.
Datad this and lav if Cotobar 1800
JOHN EDWARD WELSBY,
JAMES ROBERT WARD.
Boult & Wade,
Agents for the Applicants.