Year: 1888

page_text: Date of Application, 16th June, 1888
Complete Specification Left, 13th Mar., 1889
Complete Specification Accepted, 27th Apr., 1889
The object of this countersinker or hand brace is to countersink or rime holes
where there is no room to employ the ordinary drill brace.
The apparatus is provided with a lever arm having a boss at one end through
which there is a transverse hole. The boss has within it a ratchet wheel and a spring
pawl taking into its teeth.
The ratchet wheel has a D shaped hole at its centre and through this a mandrill
slides freely.
One end of the mandrill has upon it a screw thread carrying a nut which bears
against one side of the boss. The other side of the boss carries a collar which rests
against the work. The mandrill passes through this collar and also through the hole
to be countersunk or rimered and its other end carries the tool. By turning the
lever backwards and forwards the mandrill and tool are intermittently rotated. The
feed is given by turning the nut on the mandrill thus drawing the tool into the hole.
The tool is secured to the mandrill in the following manner.
The outer end of the mandrill has two flats or flutes cut on its opposite sides.and
a screw which is fitted with a nut of similar. shape. The tool is passed over this nut
which is then turned, a portion of a circle, to prevent the tool drawing off.
This hand brace or machine requires no cramp or frame to support it.
Dated this 16th day of June 1888.

page_text: cut in it to suit the thread e¹ cut on the mandrill, it is retained in the boss a¹ by a
screw g entering a groove cut in its circumference. The nut g abuts upon the
ratchet wheel 6 and when turned by hand draws the mandrill e upwards.
There is a flat cut on the mandrill e throughout its whole length on one side and
a second flat e at its lower end on the opposite side as shown in Figure 2 and its
extremity at e³ is reduced in diameter and receives a nut. The nut is of the same
sectional form as the mandrill at this end and it is so fixed that it cannot be removed
from the spindle but can be turned one quarter round.
The tool consists of a steel cone i in which there are three or other number of
grooves parallel to the axis. Into each groove a tooth j of hardened and tempered
steel is fitted. The root of the tooth is dovetailed as shown in order that it may be
securely retained in the groove.
In the use of the brace the mandrill is inserted through the hole to be counter-
sunk or rimed, and then the tool is put on to the spindle and secured by giving the
nut a quarter turn.
The tool cannot then escape from the spindle as the flats on the nut no longer
coincide with those on the mandrill. The hand nut g is then turned which brings
the tool to bear against the work the collar f taking the thrust on the other side. The
nut g, ratchet b, and collar fall turn together and are loosely encased by the boss a¹.
The lever a is now worked to and fro as in the use of any ordinary ratchet brace ;
the pawl engages with the teeth of the ratchet wheel 6 when the movement is in one
direction and passes them freely when the lever returns.
The mandrill is thus rotated always in one direction and the teeth ; cut away the
metal with which they are in contact.
Tools of other forms may be employed suited to the work required to be done.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. A ratchet brace provided with a collar which bears against the work on one
side whilst the tool or cutter carried by the mandrill of the brace operates on it on
the other side substantially as described.
2. A ratchet brace substantially as described and represented by the annexed
drawings.
Dated this 5th day of March 1889