IMPROVEMENTS IN RATCHET BRACES
Year: 1884

page_text: I, CASPAR SCHUMACHER of Kalk, near Cologne in the German Empire do hereby
declare the nature of my Invention for "IMPROVEMENTS IN RATCHET BRACES," and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
My Invention relates to that kind of ratchet drills which is described in the
Specification of United States Patent dated the 22 April 1884 N° 297,171, and
has for its object to render the feed motion of such drills more minutely variable.
In describing this Invention, reference will be made to the accompanying
Drawing of which Figure 1, is an axial section and Fig. 2 a plan of a ratchet drill
embodying my Invention, while the remaining Figures illustrate details.
The tool chiefly comprises a lever d, an internally screwthreaded drill-holder f, a
screw-spindle g, a feed motion-sleeve c, and two ratchet wheels having a different
pitch that is to say, one of which has a tooth more than the other.
A third ratchet wheel K may be keyed on the upper part of the sleeve c, said
wheel having one or more teeth less than the wheels on the lower part of the
sleeve.
The feed motion obtained by means of these different wheels is invariable within
the limits determined by the difference in the number of teeth of the wheels and
the pitch of the screw-thread of the screw-spindle g.
For the purpose of utilizing the intermediate sizes of feed motion, that is to say
to permit of the drilling with any suitable feed motion up to a given maximum
feed motion, the ratchet drill is subjected to the following alterations:
The feed motion sleeve is divided into two parts h and c coupled by a third
part m in such manner that any exessive feed motion or turning of the sleeve c
causes a sliding between the two coupled parts.
The sleeve c is split lengthwise, as shown by Fig. 3. and coupled with the
sleeve h (shown in detail by Figs. 5 and 6) which carries the key or feather h¹ for
turning the spindle g, by means of a conically threaded screw cap or nut m, shown
in detail by Fig. 4. This sleeve h turns the screw spindle g as hitherto, provided
that the nut m is sufficiently screwed down, to produce the necessary pressure
between the sleeve h and sleeve c by the compression of the split sleeve c.
For the purpose of reducing the feed motion, the nut m is screwed less firmly,
and the screw spindle g will only be set in motion, when the resistance of the drill

page_text: is no longer sufficient to overcome the friction between the sleeves c and h, while
otherwise a sliding motion between the sleeve c and the sleeve h takes place.
If the conical nut is completely loosened, no automatic feed motion whatever
takes place, and the ratchet drill may be used as an ordinary ratchet drill.
The division of the sleeve into separate parts may, however, be carried out in
different ways.
Either the wheel and sleeve only may be divided inside the lever, or the upper
part of the sleeve and the key which turns the spindle g may be made of two
separate parts, or the key may be entirely omitted, by coupling the sleeve c directly
with the spindle. The coupling may also be effected by a screw cap, a strap and a
conical screw.
But all modifications have the common feature, that the feed
motion sleeve is divided into two parts adapted to be coupled together by a third
part, which allows a relative motion between the said two parts, when the
resistance of the drill exceeds a certain limit.
By uncoupling the parts h and c, the operator is also enabled to turn back the
spindle g without disengaging the ratchet pawls.
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
In ratchet drills provided with automatic feed, as described in the Specification
of United States Patent N° 297,171 dated 22 April 1884.
1. The combination of a feed motion sleeve divided into two separate parts, with
an adjustable coupling adapted to allow a relative motion between the two parts of
the feed motion sleeve, under certain conditions, substantially as and for the
purposes described.
2. The combination of the axially split outer sleeve c having a conical outside
screw thread, with the inner sleeve h having a key or feather h¹, and a cap m
having an inside screw thread fitting over the screw thread of the sleeve c,
substantially as and for the purposes described.