Year: 1892

page_text: in the German Empire, 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 more particularly to the means for producing or regulating
the feed motion of the drill and for reversing the drill spindle.
In the accompanying drawing
Fig. 1 is a longitudinal section, showing a part of the drill spindle, together with
its screw nut and casing,
Fig. 2 is a top view after removal of the cover,
Fig. 3 is a side view, and
Fig. 4 a top view.
Fig. 5 indicates on a smaller scale the machine, with the spindle turned out of the
nut or casing to its full length.
A
The screw spindle a carrying the drill passes through a screw nut 6 which is
immoveable longitudinally, being secured in a case c, by means of two covers d, d.
Externally the case is provided with trunnions e, by means of which it can be
suspended in a toothed frame. The apertures for the screw spindle in the covers d, d
allow the former sufficient play. A pair of friction clutches g, g inserted in the
case c, surround the cylindrical nut balmost completely, and are prevented from
revolving together with the nut, by the shape of the case or by special means.
plate of indiarubber or other elastic material is or should be inserted between the
inner wall of the case and the lower friction clutch g', while the upper friction
clutch g is subjected to the pressure of a powerful flat spring i. By means of the
latter the cheek g is forced against the nut b, and this is driven against the friction
clutch glowing to the fact, that the spindle a which it encloses has a certain amount
of play in the covers d d.
The pressure exerted upon the friction clutches, and consequently upon the feed
nut, may be regulated by means of a screw s, in such a way, that, according to the
greater or less resistance opposed by the rock, which increases or diminishes the
friction of the spindle against the nut, the said nut turns round with the spindle to
a greater or less extent, and the feed of the drill is consequently diminished .or
increased.
The fact, that the pressure exerted upon the friction-clutches is an elastic one,
has the effect, that, when one correct adjustment has been made, the set-screw & may
be left undisturbed for a considerable length of time.
This
The said pressure originating in the nut b is transmitted to one or other of the
covers, and friction is in this way produced between the nut and the covers.
friction may be reduced by means of closed steel rings r which are inserted over the
spindles and situated between the nut and the cover in grooves or notches of the
latter. As the surfaces of these rings which receive the pressure are strongly
curved, they present only a very small rubbing surface. The exclusion of dirt is
also facilitated by these rings, inasmuch as the corners between the circular rings
and the rectangular walls of their recesses may be employed to retain or hold
grease, by which arrangement sufficient lubricating material is available for a con-
siderable length of time, and on the other hand complete protection from dust is
afforded to the moving parts contained in the case.
The introduction of fresh lubricating material may take place through the
apertures o, o, in the covers. When the boring has proceeded so far, that the
posterior end of the spindle reaches the end of the case (Fig. 5), it is sufficiunt, to

page_text: screw the spindle back as far as may be necessary to free its front end from the
drilling tool, after which the spindle, together with its screw-nut and case, may be
turned through 180 degrees, a longer drill inserted and then the drilling continued.
In consequence of the compact form or construction of this drilling apparatus, it
may be employed quite close to the roof, the walls, or the sole of the working-a
fact which greatly extends the utility or range of application of the drill.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A feed mechanism for rock drills comprising in its construction;
a. Friction clutches surrounding almost the whole circumference of the screw
nut, which produces the feed motion of the drill spindle.
b. Closed antifriction and packing rings inserted between the feed nut and the
covers of the feed nut casing, the said rings being so shaped and arranged,
as to diminish the friction between the rings and the covers, and to form a
space for the reception of lubricating material, substantially as described.
2. In a rock drill, a reversible case carrying the drill spindle and the feed nut,
said case being pivoted or suspended in such a manner, that the operation of
drilling may be alternately conducted with both sides of the drill spindle, substan-
tially as described.
DAL: 10AL
1 1000