IMPROVEMENTS IN MACHINERY OR APPARATUS FOR MANIPULATING DURING THE GRINDING OR SHARPENING OPERATION TWIST-DRILLS OR BITS, IN ORDER TO GRIND AND SHARPEN THE SAME, AND
Year: 1880

page_text: LETTERS PATENT to John Dawson Ashworth, of 7, Blackfriars Street,
Manchester, in the County of Lancaster, Engineer and Emery Wheel
Machinist, for an Invention of "IMPROVEMENTS IN MACHINERY OR APPARATUS
FOR MANIPULATING DURING THE GRINDING OR SHARPENING OPERATION
TWIST-DRILLS OR BITS, IN ORDER TO GRIND AND SHARPEN THE SAME, AND
PROVISIONAL SPECIFICATION left by the said John Dawson Ashworth
at the Office of the Commissioners of Patents on the 25th November 1880.
JOHN DAWSON ASHWORTH, of 7, Blackfriars Street, Manchester, in the County
"IMPROVEMENTS IN
of Lancaster, Engineer and Emery Wheel Machinist.
MACHINERY OR APPARATUS FOR MANIPULATING DURING THE GRINDING OR
SHARPENING OPERATION TWIST-DRILLS OR BITS, IN ORDER TO GRIND
SHARPEN THE SAME, AND IN THE APPLICATION TO METAL GRINDING WHEELS
OF A SAFETY APPLIANCE."
AND
My Invention relates in the first place to improvements in machinery or
apparatus for grinding and sharpening twist drills or bits, and has for its object to
simplify the construction and action of such apparatus.
Previous to my said Invention such apparatus have been more or less compli-
cated and difficult to operate with, and have moreover been costly.
My Invention relates in the second place to the application to metal grinding
machines, of a safety appliance to prevent accidents arising through the high speed
at which such wheels are run, that is to say, the wheel is liable to break and fly
from its axis.
When carrying out the first part of my Invention I mount on the ordinary bed
plate of such machines an apparatus which I designate the simple and accurate
twist drill grinder, consisting of a traversing carriage carrying the twist-drill or bit.
The drill or bit is fitted into a socket fitted on one end of a drill spindle. On the
other end of the said spindle a hand wheel is mounted, which, when turned in one

page_text: direction, brings the drill or bit to be ground into position with the grinding wheel.
The said spindle is supported at one end by a spring which embraces a curved arm,
and on which the drill spindle bearing may be swiveled. I fit onto the drill
spindle a cam shaped wheel which is turned by the operator against a vertical rail
connected to or formed on the carriage. The rim of the said cam shaped wheel is
turned in one direction, and during the time the operator is pressing against the
rail one of its greater diameters, one edge of the drill is ground by the grinding
wheel. After this incline on the said cam has been slid against the rail the angle
of the drill with the grinding wheel is altered, whereby the next edge of the drill
will be cleared from contact with the grinding wheel, until the other incline of the
cam is brought to bear against the rail. An important feature of my Invention
consists in giving this backward movement to the drill during the time it is being
ground, whereby I am enabled to grind and sharpen the drill in a superior manner.
When carrying out the second part of my Invention, I partly encase the grinding
wheel with a cast iron safety appliance in the form of a shield on both sides of the
grinding wheel. The upper part of each shield is formed with holes through
which bolts are passed which connects them together, and metal rods inserted
between the flange of each shield at the part over the periphery of the wheel.
Below the said flanges of the shields form therein a vee grove which supports a
strong strip of metal over the periphery of the wheel, and which leaves so much of
the wheel visible as is necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Dawson Ashworth in the Great Seal Patent Office on the
25th May 1881.
JOHN DAWSON ASHWORTH, of Number 7, Blackfriars Street, Manchester, in the
County of Lancaster, Engineer and Emery Wheel Machinist. "IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR MANIPULATING DURING THE GRINDING OR
SHARPENING OPERATION TWIST DRILLS OR BITS, IN ORDER TO GRIND AND
SHARPEN THE SAME, AND IN THE APPLICATION TO METAL GRINDING WHEELS
OF A SAFETY APPLIANCE."
My Invention relates to the combination and application to metal grinding
machines of a novel safety appliance, being suitably constructed to protect the
workman from injury when the wheel bursts, as it sometimes will, owing to the
rapid rate at which the wheel is driven, causing damage to life, limb, and property.
The said safety appliance may be constructed of cast iron, and made in the form of
a double-shield connected together at its upper part or rim by means of wrought
iron bolts, around which suitably strong hydraulic tubes are carried. Each said
shield is parallel with the grinding wheel of the machine, and it may be cast with
or formed separately from the foundation framing of the machine, and connected
thereto by means of bolts and nuts. Any suitable and corresponding number of
bolt holes may be cast in each said side shield. The hydraulic tubes are made of a
width equal to the required distance apart of the said two side shields, and the said
bolts pass through them, and are secured by turning a nut on the screwed end of
each bolt, which brings the inside of each shield to press against the tubes. A
suitably shaped strip of metal, preferably boiler-plate, is bent into a circular form
and fitted into vee or other suitably shaped recesses formed in each side shield
immediately below the said hydraulic tubes and bolt shanks.. The casing thus
formed may be made to enclose nearly the whole or any part or portion of the said
grinding wheel as may be desired. And in order that my Invention may be better
understood, I have caused to be appended hereto a Sheet of Drawings marked with
letters of reference, corresponding marks indicating the same parts. Referring in
this place to the said Drawings, Fig. 1 represents a side view of the improved
safety appliance A applied to a metal grinding machine, on each side of which a
small portion of the wheel g is exposed. In this example the side shields A are
connected to the foundation framing B by means of bolts c, but in some cases the
shields A are cast with it. The upper part or rim of each shield A is formed with
corresponding holes, through which the wrought iron bolts d are passed to connect
the two shields together, as seen more clearly in Fig. 3. Fig. 2 represents a cross
section of Fig. 1. Hydraulic tubes e are inserted between the two side shields, and
surround the said bolt shanks, and are made of a width equal to the required
distance apart of the said shields between which they are held tight. The grinding
wheel g revolves on the shaft i. A strip of boiler plate or other suitable metal h is
sprung into the recesses j. In case of fracture of the grinding wheel of such machines
which is well known cannot be obviated or prevented, the danger therefrom is
considerably lessened if not entirely overcome by the employment of the herein
described safety appliance.
In my Provisional Specification I described an appliance for grinding and
sharpening twist drills or bits, but since the filing of such Specification I have not
developed the same, and now lay no claim thereto, but what I do claim as secured
to me by the hereinbefore in part recited Letters Patent is,-
First. The form, construction, and arrangement of safety appliance, substantially
as hereinbefore described and as illustrated in the Drawings.

page_text: Secondly. The combination with and application to metal grinding machines, of
the herein before described or similar construction of safety appliance, for the
purpose specified.
In witness whereof, I, the said John Dawson Ashworth, have hereunto set
my hand and seal, this Twenty fourth day of May, in the year of our Lord
One thousand eight hundred and eighty one.
Signed and sealed in
the presence of
HUGH G. GRANT,
Of the Firm of Bosshardt & Grant,
Patent Agents,
Hopwood Avenue,
Manchester.
J. D. ASHWORTH. (L.S.)