Improvements in Ratchet Braces.
Year: 1894

page_text: Date of Application, 6th Mar., 1894-Accepted, 12th May, 1894
Improvements in Ratchet Braces.
I, BIRGER LJUNGSTRÖM, of Grefgatan 44 B, Stockholm, in the Kingdom of
Sweden, Instrument. Maker, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to ratchet-braces which are so arranged that the bit
receives a continuous motion, while the lever is moved to and fro as before.
This is effected by arranging two toothed wheels on the boring bar, which wheels
both gear with a third conical toothed wheel. The latter is alternately rotated by
means of the lever and the other wheels then alternately move the boring bar,
there being a roller catch between the wheels and the boring bar, which causes the
wheels and the bar to move together when the said wheels turn in one direction,
but not when they turn in the other direction. The boring or drilling is thus
effected much more quickly than by the ratchet-brace hitherto used, and without
the disagreeable noise peculiar to the motion of the latter.
In the accompanying drawing,
Figure 1 is a longitudinal section of the ratchet-brace.
Figure 2 is a cross-section of the same on ry, Figure 1.
Figure 3 represents the lever and
Figure 4 is a modification of the invention.
The bar a in the one end of which the bit is attached and from the other end of
which projects the common feeding screw b, passes through an intermediate piece c,
e, the
the one end of which is provided with a pin d for the conical toothed wheel
other end being provided with a hole for receiving a pin or such like for retaining
the piece c when boring. On the bar a, which passes loosely through the piece c,
These
are mounted two bevel wheels g and h, one at either side of the piece c.
wheels gear with the bevel wheel e and have in their naves or centres the rolling
catches acting against the bar. These catches consist of rollers or balls i located
parallel with the bar in recesses k made in the hub of the bevel wheel next to the
bar. Further the recesses are made wedge-shaped in cross-section and behind the
rollers or balls are springs pressing the rollers in towards the narrower part of
the recess between the wheel and the bar.
From this it is easy to understand, that the wheel will operate the bar when
being turned in one direction but not when being turned in the other direction.
On the nave of the wheel e is secured a lever for giving the wheel oscillating
movement. The wheel e when being turned by means of the lever, causes the
wheels and to turn and one of the latter for instance g operates the bar while
the other runs loose on the said. bar. If the wheel e is turned in the other
direction, the motion of the wheels g and h will be reversed, the wheel h operating
the bar while the wheel g runs loose. The bar is in this way kept in a continuous
rotatory motion the direction of which is not changed.
The toothed wheels are protected by means of plates in rivetted to the piece c
and provided with recesses in front of the place where the wheels gear with each
other but otherwise covering the teeth. The nave of the toothed wheel e is
provided with one or more longitudinal key slots n in order that a lever provided
with a key as represented in Figure 3 may be passed upon the nave, several such
slots being preferably provided in order that the lever may be adjusted in different
positions on the nave so that the same teeth may not be constantly worn.
wheel g is provided with corresponding slots m' in order that the lever may be
The

page_text: passed upon the said wheel, for the ratchet-brace can evidently be driven also from
this wheel.
In a modified form of apparatus the pin d may pivot in the piece c and can be
arranged to serve as a boring bar, and a fork-shaped lever may be employed
clasping the naves of the toothed wheels g and running loose on pivots. If in
the arms of the lever are arranged roller catches outside the naves so that the lever
operates one wheel (for instance g) when it is moved in one direction and the other
wheel when it moves in the other direction, then the wheel e and the bar receives
an uninterrupted rotatory motion.
Figure 4 represents the ratchet-brace arranged in this way and shown from the
side. The lever shown in the plane of the paper is in the reality perpendicular to
the said plane. It is principally the roller catches which are important in the
invention, as they impart an easy and sure motion to the ratchet brace and allow
by their instantaneous engagement, a continuous motion of the bar. The
mechanism can moreover when using the said catches, easily be arranged differently
so as to become as durable and practical as possible.
As the wheels-move through only a small angle to and fro, they can gear with
one another in many different ways by means of friction or by means of a projection
on the one wheel entering into a corresponding recess in the other wheel.
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. In a ratchet-brace with a continuous rotatory motion of the bar, obtained by
parts turning alternately in the one and other direction, actuated by means of a
lever and driving the bar alternately, the arrangement of roller or ball catches
causing the bar and the part driving the latter to move together when the said
driving part is turned in a certain direction or causing the lever, when being
moved to and fro, to move alternately the parts acting upon the bar.
2. A ratchet-brace, in which the boring bar is provided with two toothed or
friction wheels, which by means of roller or ball catches move the bar when being
turned in the one direction, but not when being turned in the other and by another
wheel mounted on a piece (c) traversed loosely by the bar, which wheel is moved
alternately in the one or the other direction by means of a lever and gearing with
the first mentioned wheels, all with the object of imparting to the bar a continuous
motion.
3. The modification of the ratchet-brace specified in the first claim in which the
pin of the wheel (e) constitutes the boring bar, and that the other wheels are driven
alternately by means of a fork-shaped lever, the arms of which clasp the wheel
naves and by means of roller or ball catches moves one wheel, when being turned
in one direction and the other wheel when being turned in the other direction, all
with the view of obtaining a continuous rotatory motion of the boring bar.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant..