Improvement in the Feed Mechanism for Rocking Microtomes.
Year: 1898

page_text: Date of Application, 25th Dec, 1898
Complete Specification Left, 11th Sept., 1899-Accepted, 14th Oct.. 1899
PROVISIONAL SPECIFICATION.
Improvement in the Feed Mechanism for Rocking Microtomes.
I, HUGH MARTIN LEAKE, of 16, Alleyn Park, West Dulwich, Undergraduate,
Christ's College, Cambridge, do hereby declare the nature of this invention to be
as follows:-
The razor being held by two uprights at one end of the instrument the feed
mechanism 18 carried on two uprights placed one behind the other in the middle
line of the base at such a distance apart as is required for the length of the object
to be cut These uprights are about 2 inches high Through them two shafts
pass in the middle line of the instrument, one vertically above the other. On
these, between the uprights, a block slides. This block bears the rocking aim
which lies in the middle line of the instrument and is pivoted to the top of the
block about four inches from the base so that the mechanism below will not
interfere with the rocking of this arm The lower shaft is a smooth rod passing
through the block and prevents back-lash. The uppermost of the two shafts
bears a screw thread, about 10 to inch, which fits into a concave screw through
the block It is continued behind the hinder upright for about an inch and on
its end is fitted a worm wheel about 1 inches in diameter. By turning this
wheel the block, and therefore the object on the front end of the rocking arm, 18
moved forwards. One revolution of the wheel will move the block forwards one
tenth of an inch By this means the block is made to move forwards in a straight
line and thus the section faces are practically parallel Also when once adjusted
the sections can be cut for a distance equal to the distance between the uprights
less the thickness of the block without re-adjustment and therefore without break
in the continuity of the sections. Fitted into a socket in the base immediately
below the edge of this worm-wheel is an upright 1od bearing a woim where it
touches the worm-wheel, which woim fits into the teeth of the worm-wheel
the base of this rod is fitted a ratchet-wheel and an arm hearing a pawl is pivoted
on it This pawl arm has a definite run between two stops in the base and there
18 an adjustable plate raising the pawl from the teeth for an alterable amount of
the run, and thus the thickness of the section can be varied at pleasure. By the
ordinary connection between the 1ocking and pawl aims, the rocking motion is
automatically obtained.
Dated this Twenty-ninth day of December 1898
To
I, HUGH MARTIN LEAKE, of 15, Alleyn Park, West Dulwich, Undergraduate,
Christ's College, Cambridge, do hereby declare the nature of this invention and
[Price 8d]

page_text: 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 improvements in the feed mechanism of rocking
microtomes.
According to the invention I construct my mici otome of a frame carrying
uprights and adapted to receive a sliding block, the said sliding block being
mounted on a suitable support arranged between the two uprights, such for
example as one or more shafts or spindles upon which the lower pait of the block
rests The upper part of the sliding block is provided with bearings for a locking
arm adapted to carry the object from which the sections are to be cut, and a 1azor
blade 18 mounted in the frame in front of the rocking aim. In connection with
the sliding block I also provide a feed screw which engages with a nut or nut
portion upon the said block, the said screw being mounted in the uprights; one
of the ends of the screw projects through its supporting upright and upon the
projecting end I mount a worm wheel engaging with a worm upon an upright
spindle, the lower end of which 18 provided with a ratchet wheel The operating
lever is also mounted loosely upon the lower end of this vertical spindle and is
provided with a pawl which, when the lever 18 manipulated, 18 caused to engage
with the ratchet wheel so as to turn the woim and worm wheel and thereby the
screw which moves the sliding block forward through a predetermined distance
To control the distance through which the sliding block 18 moved on each motion
of the controlling lever, I employ a cam plate, the position of which, relatively
with the ratchet wheel, can be adjusted so as to hold the pawl out of engagement
with the said ratchet wheel for a predetermined portion of the movement of the
said pawl. The rocking arm is actuated by the movement of the controlling lever,
by means of a cord on the like which 18 attached to the outer ends of the said lever
and of an adjustable arm in connection with the rocking arm, and passes over a
guide pulley.
To enable my invention to be fully understood I will describe it by reference
to the accompanying drawings in which:-
Figure 1 is a front sectional elevation of a microtome constructed according
to the invention :
Figure 2 18 a sectional plan thereof.
Figure 3 is an end elevation of the apparatus; and
Figure 4 is a section on the line 4-4 Figure 1.
a 18 the frame which is provided with feet a¹ upon which it rests and b, bare
the uprights formed near each end of the said frame a € 18 the sliding block, the
said block being provided with feet c¹, c which are supported upon the two
spindles d, d secured in lugs d', d¹ formed upon the frame a
a
e 18 the rocking arm formed upon a spindle e¹ mounted in bearings at the
upper part of the sliding block e, the said arm is provided at its end with the
usual carrier E for the embedded object A and is operated by an arm which
passes through a hole in the spindle being adjustably secured in position in the
said spindle by means of a set screw so that its length can be varied as required
f is a spindle, the cential portion of which is formed with screw-threads f¹ of
a pitch such that about ten threads are comprised in an inch, the said spindle being
mounted in bearings in the uprights b, bi The screw-threads f¹ engage in
portion of a nut c³ carried upon the sliding block c and one end f of the spindle f
projects through the bearing in the upright b 9 18 the worm wheel fitted upon
the projecting end of the said spindle and g¹ 18 the upright spindle caying
the worm which engages with the said worm wheel. This upiight spindle gi
18 mounted in bearings formed respectively in the plate g³ secured
to the upper part of the upright band in the fiame plate a h 18 the
ratchet wheel which is mounted upon the lower end of the upright spindle g¹
and is the pawl which is adapted to engage with the said ratchet wheel
2 18 the

page_text: operating lever bearing a pin on which the pawl A is pivoted, the said operating
lever being loosely mounted upon the upright spindle gl
The lever is provided with an arm to the outer end of which a cord or the
like 18 secured, the said cold passing over a guide pulley loosely mounted
upon a pivot pin secured to the frame a and being secured at its other end
to a sliding eye k mounted upon the arm e, the said sliding eye being secured in
any position to which it may be adjusted upon the said arm by means of the set
screw kl.
is the cam plate which 18 loosely mounted upon the upright spindle g¹ under-
neath the ratchet wheel h, the said cam plate being provided with a piojecting
arm which 18. adapted to be secured in position by means of a pin upon the
said arm which said pin passes up through a slot m² in a plate m and can be
secured in any position in the said slot by means of a nut m³ screwed upon the
end of the said pin . The portion of the plate m bordering on the slot m¹ 18
graduated and the aim is furnished with a pointer so that the position of the
cam plate can be accurately adjusted according to the thickness of section
required.
n 18 the razor blade, the said blade being secured at the proper inclination in
slots n¹ formed respectively in the upper end of the upright band in an additional
upright, the said blade being igidly secured in position by means of set
screws n².
is a sping for normally holding the pawl in engagement with the ratchet
wheel, 18 a spring for returning the rocking arm to its uppermost position
and q, rare stops to limit the movement of the lever in both directions
The operation of the apparatus 18 as follows-
Assuming the embedded object A mounted in the carrier E on the rocking arme
in the usual manner and the cam plate adjusted so that the rocking aim 18
fed forward the required amount at each manipulation of the lever, the said
lever is moved in the direction of the arrow Figure 2, thereby lowering the rocking
arme through the medium of the cold, and adjustable aim in the manner
hereinbefore described; the downward movement of the rocking arm e brings the
embedded object on to the projecting cutting edge of the razor blade n which cuts
the section. The lever is then turned back, that is to say, in the direction
opposite to that indicated by the airow in Figure 2 and the locking arm e 18
eturned to its uppermost position by the spring P The return movement of the
lever brings the pawl into engagement with the ratchet wheel thereby
feeding forward the sliding block c in the manner hereinbefore described to an
extent determined by the position to which the cam plate has been adjusted.
By repeating this operation a complete series of successive sections can be obtained.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same 18 to be performed, declare that what
I claim 18.
1. In a microtome, the combination with the frame or support, of a sliding
block having a rocking arm for carrying the embedded object, of means for rock-
ing the said arm and of means for feeding the sliding block, both such means
being controlled by a single lever, substantially as herein before described
2. In a microtome of the kind described in Claim 1, the employment for
feeding the sliding block, of a screw engaging with a nut in connection with the
said block and adapted to be rotated by means of ratchet and worm gear, sub-
stantially as herein before described
3 In a microtome of the kind wherein a sliding block operated by ratchet,
woim and screw mechanism is employed, the arrangement for controlling the
amount of feed, comprising an adjustable cam plate in connection with the ratchet
and pawl mechanism which said plate holds the pawl out of engagement with
the ratchet wheel for a portion of its motion corresponding to the position to which
it 18 adjusted, substantially as described

page_text: 4. In a microtome the arrangement of a sliding block mounted in a support
and having a rocking arm carrying the embedded object and an adjustable
operating arm of a feed screw for the sliding block and of a pivoted operating
level carrying a pawl and connected to the operating arm by a cord or the like,
the said fever when moved in one direction moving the rocking arm so as to
bring the embedded object against a razor blade and when moved in the other
direction feeding forward the sliding block through the medium of the pawl
which engages a ratchet wheel and actuates the feed screw, substantially as herein-
before described.
5 The combination and arrangement of parts forming the improved micro-
tome, herein before described and illustrated in the accompanying drawings.
Dattu
де
Tth day of september
G. F REDFERN & Co,
4, South Street, l'insbury, London,
Agents for the Applicant
G. F REDFERN & Co,
4, South Street, Finsbury, London,
Agents for the Applicant