IMPROVEMENTS IN EXPANDING BORING TOOLS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, THO HARRISON Special Tool & Machine Maker Manor Tool & Machine Works
Idle Rd Undercliffe, Bradford, Yorkshire do hereby declare the nature of my
invention for "IMPROVEMENTS IN EXPANDING BORING TOOLS," to be as follows:-.
by means of a Rack & Pinion, each Cutter having on its internal Edge a rack.
into which a Pinion geara which on being turned or moved part way round
expands or closes the Cutters as required the Cutters being then locked by means:
of set screws passing through part of drills & pressing on the Cutters, I show
sketch but do not bind myself to details.

page_text: I, THOMAS HARRISON of Manor Tool and Machine Works, Idle Road, Undercliffe,
Bradford, in the County of Yorkshire, Special Tool and Machine Maker do hereby
declare the nature of my said invention for "IMPROVEMENTS IN
EXPANDING
BORING TOOLS," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement reference being had
to the accompanying drawing forming a part of this specification :-
My invention relates to improved means for expanding and retracting the
inserted cutters in drills, boring bars and similar tools.
My invention consists in providing the said cutters with racks, the said racks
gearing into a pinion, by the revolution of which the said cutters can be expanded
or retracted, suitable means being provided for securely retaining the said cutters
in any desired position.
In the accompanying drawing Figure 1 is a longitudinal section, Figure 2, a
transverse section on the line x x Figure 1 Figure 3 a side view and Figure 4 a
plan of a flat shank boring bar for lathe purposes with my improvements applied
thereto.
Like letters indicate like parts in all the figures.
The cutters-a-are provided with shank-like extensions a¹ the said extensions
being on the opposite sides of the inner ends of the said cutters. Each of the said
extensions has formed on or secured to its inner edge a rack b. Thus when the
cutters are inserted in the bar the said extensions and the racks formed thereon
lie parallel to and opposite each other with a space between them in which is
mounted a pinion con a shaft c¹ having its bearings in the bar. The said pinion
gears into the racks b of both cutters a and it will thus be seen that by revolving
the said pinion the cutters a can be expanded or retracted to the desired extent
equally and simultaneously. The shaft c¹ of the pinion is provided with a suitable
head by which the said shaft can be revolved and the opposite end of the shaft
is provided with a collar d by which the pinion is held in position.
For retaining the cutters a in the desired position I provide each cutter with
a set-screw e passing through the bar and pressing upon a plate or die f near
the cutting edge of the cutter the said cutter being thereby held or locked in the
desired position.
I wish it understood that I do not confine myself to the precise details herein
set forth as the same may be varied without departing from my invention, but
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
-
First. In expanding boring tools, the pinion c, and the racks b formed on or
secured to the cutters a combined, arranged and operating substantially as and for
the purpose sot forth.
Second. In expanding boring tools, the pinion c and racks b on cutters a in
combination with the set-screws e and plates or dies f or other suitable means for
locking or securing the cutters a in the desired position.
Dated this thirteenth day of January AD. 1885.