IMPROVEMENTS IN APPARATUS FOR GRINDING, CUTTING, DRILLING, AND TAPPING METAL AND OTHER MATERIALS
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by John Donnelly at the Office of the
Commissioners of Patents on the 24th September 1877.
JOHN DONNELLY, of 176, Campbell Road, Bow, in the County of Middlesex,
Engineer. "IMPROVEMENTS IN APPARATUS FOR GRINDING, CUTTING, DRILLING,
AND TAPPING METAL AND OTHER MATERIALS."
My Invention relates to novel apparatus for facilitating the grinding or cutting
of metal and other materials in a lathe, and also for drilling and tapping or forming
screw threads in holes in metal and other materials, and consists in the novel
construction of the said apparatus and in the means for operating the same.
The said Invention comprises, first, an apparatus which is designed to form an
attachment or addition to an ordinary turning lathe, and which is provided with an
emery wheel or other suitable grinding wheel or roller. This wheel or roller is
mounted on a shaft or spindle which is fitted to turn freely in bearings in a forked
arm formed of iron or other suitable metal, and the said roller is fitted in the space
between the two sides or jaws of the said arm. The said shaft is kept in place by
pins or keys driven through the sides of the bearings, and may be readily released
by driving out the said pins or keys. The said forked arm is pivotted or jointed to
a bracket or plate, which is designed to be secured on the back of the headstock of
the lathe. For this purpose the said plate has two jaws which clip the ends of the
headstock, and one of the said jaws is made adjustable so that the said plate can be
adjusted to headstocks of different sizes, and is provided with pinching screws or
other means for tightening or fixing it in place.
The required rotary motion is communicated to the said grinding wheel or roller
from the cone pulleys of the latter; and I prefer to transmit this motion from the
said cone pulleys through the medium of a flexible shaft, that is to say, a shaft
constructed of spiral wire enclosed in a tube or covering of any suitable material.
I connect one end of this flexible shaft by any suitable coupling device with the
shaft or spindle of the grinding wheel or roller, and the other end to the shaft or
spindle of a friction wheel or pulley, which shaft or spindle is fitted to rotate in
the end of a forked bar within or between the jaws of which the said friction
pulley works.
By bringing the rim of this friction pulley into contact with the
[Price 2dl

page_text: rim of one of the cone pulleys the motion of the latter will be imparted to the said
friction pulley and to the flexible shaft, and the latter will transmit such motion to
the grinding wheel. The pivoted arm on which the latter is carried and the flexible
shaft will allow the adjustment of the said grinding wheel into any desired position
to suit the shape of the article or object to be ground in the lathe.
In some instances I use a weight or spring properly arranged to keep the said
grinding wheel in forcible contact with the surface on which it is operating. This
apparatus will greatly facilitate the grinding or "trueing up" of the lathe centres
without the necessity of removing and softening them.
If preferred, instead of using a flexible shaft for driving the said grinding wheel
or roller I may employ for this purpose a belt or strap passing over one of the
cone pulleys and over a pulley connected with the shaft or spindle of the said
grinding wheel.
For cutting wood and other comparatively soft materials I substitute for
the said grinding wheel or roller a rotary cutter, and operate the same as above
described.
To adapt my Invention for drilling and tapping holes in metal or other materials
I modify the same as follows, that is to say-Instead of a grinding wheel or rotary
cutter driven by the said flexible shaft, or otherwise, I arrange between the jaws
of a suitable bracket or holder a worm which is mounted upon a rotary shaft or
spindle, which turns freely in bearings in the said bracket. The said worm is geared
with a worm wheel of any desired diameter, and which is mounted upon a shaft or
spindle which is fitted to rotate in suitable bearings in the said bracket, and which is
provided at one end with a socket for the reception of a drill or perforating
implement or a screw tap. Opposite to the said spindle the said frame or bracket is
formed with a screw neck, wherein is fitted a screw stem or spindle provided with
a hand wheel whereby the feed of the drill or other implement is effected when the
apparatus is at work.
The said frame or bracket is preferably provided with excentric bearings for the
worm shaft, and these excentric bearings are connected with a handle or bar by
turning or adjusting which the worm may be readily set into or out of gear with
the worm wheel.
By means of this apparatus I am enabled to utilize the aforesaid flexible shafts
much more advantageously than has heretofore been practicable for drilling
and tapping holes in iron and other metal, as by means of the worm gearing
above described I can apply very great force to the tool without injuring the
flexible shaft.