Improvements in Rocking Microtomes.
Year: 1893

page_text: Date of Application, 14th Apr., 1893-Accepted, 20th May, 1893
Improvements in Rocking Microtomes.
HORACE DARWIN, St. Tibb's Row, Cambridge, Scientific Instrument Manu-
facturer, 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 :-
The rocking microtome is an instrument for cutting sections of any soft material
for microscopic examination. The object to be cut is fixed in the holder and my
invention relates to the method of clamping the holder to the rocking arm of the
microtome and to the means of adjustment of the object by screws so that the
sections are cut in the desired plane.
Fig. 1 is a vertical section of the holder and of the end of the rocking arm.
Fig. 2 is a horizontal section of the same.
Fig. 3 is a cross section through A. B.
Fig. 4 is a cross section through C D.
Fig. 5 shews the cup P and the flange T.
Fig. 6 is a cross section through E F shewing the flange U.
The cylindrical end G of the rocking arm is made so that the tube H will slip
easily over it. A hole is drilled along the axis of the cylindrical end G of the
rocking arm, and a cylindrical rod K with an enlargement at K (shewn in Figs. 1
and 2) is slipped into this hole. When the screw L is turned, its point bears on
the inner end of the rod K; the rod acts as a lever turning about the enlargement
at K as a fulcrum and forcing the stud M against the inner surface of the tube H
and clamping the holder firmly. This stud M is slipped through a side hole
through the end of the rocking arm into a cross hole through the rod K and is
fixed by a screw N.
The cylindrical end of the rocking arm is not truly cylindrical, as a flat surface
(shown at O) is filed on its lower side; this ensures firm clamping.
The object to be cut is embedded in paraffin or otherwise fixed in a spherical
cup P held at the outer end of the holder. The object projects beyond the cup
and as the rocking arm rocks on its horizontal axis, sections are cut by the fixed
razor or knife. The cup P can be turned in every direction by the screws Q. R. R;
thus the object is placed in the right position for cutting sections in the required
plane. If either of the nuts with milled heads S S are tightened, the cup P is
firmly held against the open end of the tube H. If one nut S is loosened and the
other tightened, the cup P with the embedded object is turned about a vertical
axis. The ends of the screws R R are enlarged so that they will not pass through
holes in the flange T fixed to the cup P. These holes are made conical at the
back, so as to allow the cup P to turn in all directions. The other ends of the
screws R R pass through holes in the flange U fixed to the tube H; these holes
are also made conical on the side opposite to the face against which the nuts $ S
bear. The projecting piece V fixed to the bottom of the cup P is pressed against
the point of the screw by the spiral spring W. If this screw is turned the cup P
is turned about a horizontal axis. The two ends of this spring W are hooked into
holes in the flanges T and U as shewn. The ends of a half ring of wire are bent
at right angles and are passed through holes in the screws R R, as shewn at X;
thus the screws R R are prevented from rotating when the nuts S S are turned.

page_text: 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 lever clamp for fixing the object holder to the rocking arm of the rocking
microtome, substantially as described.
2. The use in rocking microtomes of a hollow spherical cup to receive the
object, the back of the cup forming a ball and socket connection with the rest of
the holder.
3. The use in rocking microtomes of adjusting screws to allow adjustment of the
plane of the object in two directions.
4. The combination of the spherical cup and adjusting screws substantially as
described.
SA 1000
HORACE DARWIN.