A NEW OR IMPROVED SELF-FEEDING DRILLING OR RATCHET BRACE
Year: 1879

page_text: LETTERS PATENT to Thomas Moore, of Gerrard Street, Islington, Engineer, for
the Invention of "A NEW OR IMPROVED SELF-FEEDING DRILLING OR RATCHET
BRACE"
Sealed the 19th December 1879, and dated the 5th July 1879.
PROVISIONAL SPECIFICATION left by the said Thomas Moore at the Office of
the Commissioners of Patents on the 5th July 1879.
THOMAS MOORE, of Gerrard Street, Islington, Engineer. "A NEW OR IMPROVED
SELF-FEEDING DRILLING OR RATCHET BRACE."
This Invention relates to a new or improved self-feeding drilling or ratchet
brace.
According to my Invention the feed after being once set regulates itself auto-
matically, according to the more or less hard nature of the substance being drilled.
This I accomplish as follows:-Working concentrically into the upper or outer side
of the head of the brace is a stiff screw forming at its outer end the ordinary
point on which the brace turns, and against which the thrust or feed is exerted.
Surrounding this screw concentrically and bearing against the face of the brace
head is a collar (termed by me frictional feed collar) having on its inner circum-
ference a feather taking into a groove cut along the face of the screw in a line
parallel with its axis. The said collar is clipped on its outer circumference by a
pair of fingers attached at their other ends by a pin which also centres them to the
handle of the brace. The strength with which they clasp the said collar, and thus
the friction exerted thereon, is regulated by a screw passing through both fingers
between the point where they are centred and the said collar, and having a shoulder
bearing against the near finger. The two may thus be tightened up or slacked out
as required. This screw may be operated by an ordinary finger and thumb piece,
or by worm and pinion or otherwise, as required.
At the commencement of working the fingers are left quite slack, and the brace
is set to its work in the ordinary way until the tool has got fairly hold of the

page_text: metal The fingers_are_then gradually closed upon the frictional feed collar until
their hold on it is sufficient to turn it at the backward-stroke_of_the_handle to
which the fingers are attached. The collar in turning imparts, by reason of its
feather, like motion to the screw, screwing it backwards or out of the head of the
brace, and thus feeding the brace to its work. When the screw has advanced as
far as the required feed will allow the fingers then slip over or round the feed collar
during any continued backward motion of the handle. In the forward motions of
the brace of course the whole moves together, and there is no relative action
between-its-parts. Thus the cut made during the forward motion of the brace is
equalled by the feed during the backward motion of the handle.. The feed screw
is of such a pitch that without the slip on the feed collar it would at all times give
more feed than required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Moore in the Great Seal Patent Office on the 5th January
1880.
THOMAS MOORE, of Gerrard Street, Islington, Engineer. "A NEW OR IMPROVED
SELF-FEEDING DRILLING OR RATCHET-BRACE'
"
This Invention relates to a new or improved solf-feeding drilling or ratchet-
brace.
According to my Invention the feed of the drill up to its work is automatic and
constant after having been set, and may be made at will slow or quick, so as to
give a light or heavy cut, as desired. In accomplishing this I cause each backward
stroke of the ratchet lever or handle to act by friction on a screw or its equivalent,
so as to lengthen the tool between the drill and the point taking the thrust (and
on which the brace turns), thus feeding the drill up to its work. The friction by
which the feed is thus obtained may be regulated at will, and so as to allow of
slip after the desired feed has been given. A heavy friction will give a quick
feed, and vice versa.
I will now proceed to describe my Invention fully with the aid of the
accompanying Drawings, in which Fig. 1 is a longitudinal elevation; Fig. 2, a
sectional elevation at a, b, Fig. 1 (screw B being shown in full); & Fig. 3, a
sectional plan at c, d, Fig. 1; Fig. 4 is an elevation partly in section of a modifi-
cation of my Invention; and Fig. 5, a sectional plan at e, f, Fig. 4. The .same
letters of reference indicate corresponding parts in all the several Figures. A is
the body of the brace, and A¹ the socket of the drill. The body A is bored out
concentrically, as at A², the upper portion of the bore being tapped to receive:feed
screw B, the upper or outer end of which is formed to take the thrust of the feed
against the drill and for the brace to turn on; C is the ratchet and handle or lever,
and E a collar which with the shoulder D together form the bearings for the ratchet
lever or handle to revolve between; F is a collar surrounding the screw B closely
but loosely, and having on its inner surface a pin or feather F¹ taking into a slot B¹
in screw B. This collar F is grasped around its outer periphery by two fingers G,
their grip on the collar F being regulated by a thumb screw H. The surfaces of
F & G in contact may be formed as shown or otherwise, at pleasure. The outer
ends of the fingers G are centred at G₁ to the lever or handle of the brace, and a
screw G2 with head passes through or between them to hold them down in their
position and counteract any tendency the collar F may have to rise from the body
of the brace. The action of the brace is as follows:-In starting the brace it is
preferable that the thumb screw H be well slackened and that the feed be set in
the ordinary way, and so continued until the drill has got fairly hold of its work.
The thumb screw is then turned until a gentle pressure is exerted by the fingers &
on the periphery of frictional collar F. This done, the backward motion of the
lever or handle of the ratchet will have a tendency to turn the frictional collar F
with it, and thus by means of the pin or feather F¹ taking into the slot B¹ in the
screw B to turn or screw out the said screw B and thus feed the drill up to its
work. During each backward stroke of the ratchet lever so long as the friction of
the fingers G on collar F exceeds the friction between the outer point of screw B
and the surface against which it turns, the collar F and screw B will continue to be
turned and the feed to be put on as described, but directly the friction of the latter
exceeds that of the former the fingers G will slip round collar F and the feed will
stop. Thus the amount of feed will always depend on the strength with which
fingers G are made to grasp the collar F, or in other words, on the friction between
them, and this is easily and certainly adjustable by the thumb screw H. When
the cut of the drill has fairly commenced one adjustment will suffice for the whole
operation. To render the action of the thumb screw H more sensitive a differential
screw, as shown, may be employed when desired.

page_text: In the modified form of my Invention, as illustrated at Figs. 4 & 5, the screw B
is-covered in so as to keep out dirt. In this form-the-screw-B-is fixed to or is part
of-the-body of the brace. The point I to take the thrust of the feed against the
drill-and-form the centre on which the brace turns is apart from screw B, and is
continued in cylindrical form, surrounding the screw B concentrically, and its lower
part being tapped to take onto the screw, as shewn. This cylinder is again
surrounded concentrically by another cylinder formed by a continuation of the
frictional collar F, a shoulder f¹ or close joint at its outer end shutting in the
annular space between the two. The rotary motion of the collar and cylinder F is
in this case imparted to cylinder and bearing point-I by a feather F¹ on the inner
circumference of cylinder F taking into a slot in the outer circumference of
cylinder I, which on thus being wholly or partially rotated is forced upwards or
outwards on the screw B, and thus the feed is obtained.
In either form of my Invention above described after the brace has done its work
by slackening the thumb screw E the part previously fed out may be easily and
readily returned to its position. The pitch of the screw B should be as fine as
possible, but should be sufficiently coarse that it would always give more feed than
required but for the slip of fingers G on collar F.
I claim as my Invention to be secured by the herein before in part recited Letters
Patent,
1. The combination in self-feeding drilling or ratchet-braces of screw B, collar F,
fingers G, and feed adjusting screw H (or their equivalents), substantially as herein-
before set forth and described and illustrated in Figs. 1, 2, & 3 of the accompanying
Drawings.
2. The combination in self-feeding drilling or ratchet-braces of screw B, point
and cylinder I, collar and cylinder F, fingers G, and feed adjusting screw H (or
their equivalents), substantially as hereinbefore set forth and described and illus-
trated in Figs. 4 & 5 of the accompanying Drawings.
In witness whereof, I, the said Thomas Moore, have hereunto set my hand
and seal, this 1st day of December, in the year of our Lord One thousand
eight hundred and seventy nine.