DE2411535A1 - MICROTOME - Google Patents

Description

DR. BERG DIPL.-ING. STAPF DIPL.-ING. SCHWABE DR. DR. SANDMAIR

PATENT LAWYERS

8 MÜNCHEN 86, POSTFACH 86 02 45 t \ β Λ Λ C η C

Attorney's file 24 847 ^{11 March 1974}

Kent Cambridge Medical Limited Cambridge / Cambridgeshire / Great Britain

Microtome

The invention "relates to improvements to a microtome" In particular, the invention relates to such microtomes "in which a first member is a knife and a second Member carrying an object holder, the first and second members along a straight line relative to one another are movable to cut a layer of predetermined thickness by the knife from an object, which is held by the Öbjekthalter, and in which one Advice circuit is provided through which automatically after each cutting operation in a direction perpendicular to the direction of relative movement of the links measured distance between the knife and the specimen holder can be reduced ο

409839/0297

(0811) 98 82 72 8 Munich 80, Mauerkircherstraße 45 Banks: Bayerische Vereinsbank Munich 453

<089> 98 70 43 Telegrams: BERGSTAPFPATENT Munich Hypo-Bank Munich 389 2623

98 3310 TELEX: 05 24 560 BERG d Postscheck Munich 653 43 -808

In known microtomes, the ratchet circuit consists of a ratchet wheel, which rotates on the second Member is fixed and arranged so that a rotation of the ratchet wheel in one direction of rotation by a predetermined Angle generates a corresponding predetermined movement of the object holder towards the knife, one on the second link pivotally mounted lever, which one into the ratchet wheel during the pivotal movement of the Lever in one pivoting direction for rotating the ratchet wheel engaging pawl carries a release element, which is attached to the first link such that it is on the lever during relative movement of the links attacks in one direction and thereby the pivoting of the lever effected in one pivoting direction, as well as from a stop element on the second link, which is arranged so that the pivoting of the lever is stopped by the release element at a predetermined point will. It has been found that with such an arrangement, the inertia of the ratchet wheel increases the tendency there is that this continues the twisting movement after the pivoting of the lever is stopped by the stop element is. As a result, the object holder is moved beyond the predetermined position, which is for the desired Object thickness is required in the subsequent cut.

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In accordance with the invention, a microtome is as described Kind created in which the ratchet mechanism is a ratchet wheel which is rotatable on one of the relative to each other movable links attached, and which is arranged such that the rotation of the ratchet wheel in one direction of rotation by a predetermined angle causes a corresponding predetermined decrease in the distance between the knife and the object holder, a lever arrangement, which is pivotally attached to the same link and carries a pawl which engages in the ratchet wheel during the pivoting movement of the lever arrangement in one pivoting direction for rotating the ratchet wheel in one rotational direction engages, a release element which is attached to the other of the relatively movable members so is that it engages the lever assembly during the relative movement of the links in one direction and thereby causing the pivoting of the lever arrangement in one pivoting direction, as well as having a stop element, which is attached to the first-mentioned member of the members movable relative to one another and so arranged is that it is on the lever assembly for stopping the pivoting movement of the same by the trigger element at a predetermined Attacking point · The lever arrangement shows

Means by which during part of the panning
movement of the lever arrangement ^ rmittelbar before their engagement

the speed of rotation of the ratchet with the stop

409839/0297

wheel is reduced, which by a given speed the relative movement between the relatively movable members is effected.

Preferably, the lever arrangement comprises a main lever carrying the pawl, an auxiliary lever which on the Main lever for pivoting about an axis parallel to and at a distance from the pivot axis of the main lever pivotally mounted and arranged so that the trigger element is at a point on one side of the pivot axis acts on it, an elastic spring device which is connected to the main lever and the auxiliary lever is that the main lever of the pivoting movement of the auxiliary lever follows when the trigger element engages on this, as well as a second stop element, which is arranged in this way is that it is opposite to the auxiliary lever at a point on the side of its pivot axis whose point of contact with the release element engages before the main lever with the first-mentioned stop element engages so that during part of the pivoting movement of the lever assembly immediately prior to engagement of the main lever with the first stop element of the auxiliary lever relative to the main lever against the spring force of the spring device pivoted, whereby the by a predetermined relative movement between the relatively movable members

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given speed of the pivoting movement of the main lever is decreased.

The invention is illustrated below by means of examples Explained with reference to the drawing. In the drawing shows:

1 is a perspective view of a sled microtome constructed in accordance with the invention.

FIG. 2 is an end view of the slide of the microtome from FIG. 1 in the direction of arrow II in FIG. 1,

Fig. 5 is a side view of the carriage, partially in Section along line III-III in Fig. 2, wherein the Specimen holder is omitted for clarity of illustration,

Fig. 4 is a cross section along line IY-17 in Fig. 3, which also contains a fragment of a side wall of the bed base in which the carriage moves, and the trigger assembly attached to the wall shows

5 shows a view of the release arrangement and of the slide from below, partly in section the line V-Y in Fig. 4,

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6 shows a section of part of the slide from below and

]? ig. 7A and 7B are schematic views from below of one Part of a ratchet circuit of the slide, the circuit being shown in two successive operating positions

The slide microtome shown in the drawing is except for the advice circuit described in detail below similar to the microtome disclosed in U.S. Patent 3,757,591 is described.

The slide microtome shown in the drawing has a box-shaped bed base 10, which consists of end walls 12 and 14 and side walls 16 and 18, which carry horizontal rails 20. In addition, the microtome has a slide 22 which rests on the rails 20 is slidable. Near one of its ends, the bed base 10 carries a knife 24 which is mounted in knife holders 26 is through which the cutting angle and the orientation of the knife can be adjusted while the cutting edge of the knife is held in a horizontal plane above the Mxveau of the rails 20. The carriage 22 has a top wall 23, side walls 25, an end wall 27 and a short bottom wall 29, which extends between the side walls

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ten walls 25 "adjacent to the end wall 27 extended

A carrier 28 "is attached to one end of the carriage 22, on which an object holder 30 (only shown in Fig.i) is supported. The carrier 28 is vertically movable relative to the carriage and during its vertical movement by the engagement of a guide member 32 attached to the carrier in a dovetail groove in the end v / and 27 of the slide. The object holder 30 is used to hold of an object, such as object 36 in Mg. 1, so that when the carriage 22 is manually displaced along the rails 20 by means of the handle 38, from the object 36 a layer is cut off when it passes the knife 24. There is a ratchet mechanism in the slide attached, which as a whole with the reference number 40 (lig. 3 to 5) and which is operated at the beginning of each cutting stroke, as described below, so that they can Carrier 28 and thus the object holder 30 by a predetermined Level increases. Thus, the object holder is raised between the cutting operations by an amount equal to desired thickness of the layer to be cut from the object.

The ratchet circuit 40 comprises a horizontally lying ratchet wheel 42, which at the lower end of a vertical Threaded rod 44 'is attached. The ratchet 42 and

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the rods 44 are attached by means of a bearing ball 46 to a bearing member 48 which is fixed to the bottom wall 29. The rod 44 and the ratchet wheel 42 are held in their position by a spring-loaded screw 52. The threaded ring 54 is pivotable between two positions, in one of which it engages the thread of the rod 44 and in the other of which it can be moved freely over the threaded rod, as described in US Pat. No. 3,757,591. When the threaded ring 54 is provided with the thread of the rod 44 into engagement, causes a rotation of the rod by rotation of the ratchet wheel in the counterclockwise direction in the I ¹ Xg. 5 and 7> that the threaded ring and therefore the carrier 28 and the object holder 30 are moved upwards by an amount which is proportional to the angle through which the ratchet wheel has been rotated.

A main lever 60 is arranged under the ratchet wheel 42, which is pivotally mounted on the bearing member 48 between the wall 29 and a flat 26 on the bearing member 48, so that the lever 60 is pivotable about the same vertical axis about which the ratchet wheel is rotatable. One latch 64 is pivotally attached to one end of the main lever 60

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and is resiliently engaged by a spring 66 (Fig. 4) printed with the ratchet 42 so that pivoting of the main lever 60 counterclockwise in FIGS. 5 and 7, a rotation of the ratchet wheel in the same Direction causes. During the movement of the main lever in the opposite direction, the pawl 64 ratchets via the teeth of the ratchet wheel 42, which is stationary during this movement by a second spring-loaded one Pawl 67 is held, which is pivotally mounted on a lever 68 which is coaxial with the main lever 60 is arranged. The lever 68 is normally stationary but can be held at a predetermined angle by manually operating the lever 24 on the top wall of the carriage are pivoted, as more clearly described in US Pat. No. 5,591. This enables the Raise the specimen holder in fixed steps while adjusting the microtome before starting the cutting process.

At the end opposite the pawl 64 carries the Main lever 60 an auxiliary lever 70 (Fig. 4, 5 and 7), wel- · rather, is hinged to a pin 72 for pivoting about a vertical axis. One end 76 of the auxiliary lever protrudes beyond the end of the main lever. A tension or tension spring 78 is between the other end of the auxiliary lever

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lever 70 and a fixed point 80 of the main lever 60 so clamped, that the auxiliary lever for pivoting relative to the main lever clockwise in the Pig. 5 and 7 is biased. A stop 82. which is at the end of the auxiliary lever 70 is formed, engages on an edge 84- of the main lever 60 to limit the movement of the auxiliary lever under the action of the spring 78. The spring strength of the mainspring 78 is sufficiently high to ensure that a movement of the end 76 of the auxiliary lever 70 in the opposite Direction a pivoting of the main lever 60 or a rotation of the ratchet wheel 42 counterclockwise causes without a noticeable relative rotation between the auxiliary lever 70 and the main lever 60 takes place, until the main lever 60 is positively held against pivoting «

A trip assembly 86 (Figs. 4 and 5) is attached to the side wall 18 of the bed base 10 so that it can the protruding end of the auxiliary lever 70 engages when the carriage 22 towards the knife 24 at the beginning of each cutting stroke is moved. The trip assembly includes a generally U-shaped body 88 on which a screw 90 is attached, which extends through a horizontally extending Slot 92 extends in the wall 18 and carries a clamping button 94 through which the body 88. in its place

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ment is maintained. Each releasing the clamping button 94 can the trigger assembly along the slot 92 "are moved, so that the position of the carriage" as it moves can be set, at which the help she "at the trigger arrangement strikes. A lever 96 is on the one end of the body 88 is secured by a vertical pivot pin 98 "and carries one at the other end Release pin 100, the lower end of which is arranged in the normal position so that it is at the protruding end of the auxiliary lever 70 "engages during the movement of the carriage. A tension spring 102, which between the end of the lever 96 ■ is adjacent is clamped to the pivot pin 98 and the base of a stud bolt 104 attached to the body 88, pushes the Lever 96 in its normal position. In this he attacks a stop which is formed by a nut 106 which is screwed onto the threaded end of the stud screw 104 is. In contrast, a pivoting movement of the lever for moving the pin 100 is out of engagement with the auxiliary lever 70 allowed at the ends of its path of movement. A guide member 109 (Figures 4 and 6) attached to the carriage attached, engages pin 100 to allow pivoting movement of lever 96 during movement of the lever 70 is prevented in one direction or the other.

The ends of the main lever 60 and the auxiliary lever 70 protrude

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through an opening 108 in the adjacent side wall 25 of the carriage 22 through. Two plates forming stop members 110 and 112 "are on side wall 25 at one end of the opening 108 by means of visual screws 114 ". The stop member 110 protrudes into the opening 108 and is so arranged that it can attack the main lever 60, so that this is stopped at a predetermined point "when pivoting the lever, which by the engagement of the auxiliary lever 70 in the trigger assembly 86 caused became. The other stop member 112 also protrudes into the opening 108 and is arranged so that it is on the Auxiliary lever 70 engages at a point which is on that side of its pivot axis 72 which is the protruding Is applied at the end of 76. The main lever 60 "moves over this stop member. The stop member 112 is arranged so that it is on the auxiliary lever 70 during the Pivoting movement of the main lever 60 by a few angular degrees before the engagement of the stop member 110 with the main lever 60 attacks.

The distance by which the object holder 30 is raised each time the ratchet circuit is actuated is by means of an adjustable mechanism comprising a lever 116 fixed coaxially with the ratchet 42. The lever 116 has an arcuate cam surface 118 on

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which a driver 120 engages the pawl 64 so that the pawl is pulled out of engagement with the ratchet wheel 42 is. Thus, the pawl 64 moves counterclockwise during the pivoting movement of the main lever 60 only then engages with the ratchet wheel 42 when the driver 120 reaches the end of the cam surface 118. The angular position of the cam surface 118 can be adjusted by turning of the button 122 can be changed, by which a pinion is rotated, which is connected to a rack 126 engages the end of the lever 116 so that the lever 116 is pivoted.

The described microtome includes a mechanism which is actuated by the lever 130 and by which the threaded ring 54 can be tilted out of engagement with the threaded rod 44 so that the carrier 28 can be rotated of button 132 can be raised or lowered quickly. Turning the knob 132 is through a Gear assembly 134 and a connecting rod 136 Rotated pinion 138, which engages in a rack 140 which is attached to the bracket 28 "This mechanism is more clearly described in U.S. Patent 3,757,591.

When the microtome is in operation, it engages when the slide moves towards the knife 24 at the beginning of a cutting stroke

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, the outer end of the auxiliary lever 70 to the pin 100 of the trip assembly, as shown in Fig. 7A. Through this. If the pawl 64 reaches the end of the cam surface 118, it is moved into engagement with the ratchet wheel 42, which is therefore moved together with the main lever 60 is rotated to raise the object holder 30. When the auxiliary lever 70 engages the stop member 112, the auxiliary lever 70 relative to the main lever 60 against the ^K raft of the spring 78 is pivoted, as shown schematically in Fig. 7B. This movement continues until the main lever 60 strikes the stop member 110 to stop the levers, after which the lever 70 disengages from the trigger assembly as described above and the carriage is moved further to complete the cutting stroke. During the final portion of the movement of the levers 60 and 70, the protruding end 76 of the lever 70 moves farther than the adjacent end of the lever 60 so that the angular velocity of the main lever 60 is reduced. When the carriage is moving at a constant speed, the angular velocity of the lever 60 is decreased by a factor (X / Y) sin 0 , where, as shown in Fig. 7B, X and Y are the distances measured in a direction perpendicular to the direction of movement of the carriage

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the pivot axis 72 of the lever 76 ″ or the release pin 100 and the point of application of the stop member 112 on the heloel 70, and 0 is the angle between the connecting line between the pivot axis 72 and the point of contact of the lever 70 with the pin 100 and the direction of movement of the slide The speed of rotation of the ratchet wheel 42 is thus reduced over the last few angular degrees of its movement and the risk that the wheel will run beyond the desired end position is reduced.

- Expectations -

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409839/0297

Claims (1)

Patent claims: / 1J microtome with two relatively movable one against the other Limbs, one of which carries a knife and the other an object holder, and with a counseling circuit .to change the distance between the knife and the specimen holder, characterized in that the ratchet circuit is a ratchet wheel which is rotatable on one of the relative is attached to each other movable members and is arranged so that the rotation of the ratchet wheel in the one Direction of rotation by a predetermined angle results in a correspondingly predetermined reduction in the distance between the knife and the object holder causes a lever assembly pivotally attached to the same link and a pawl carries which engages in the ratchet wheel during the pivoting movement of the lever arrangement in the one pivoting direction and thereby causing the ratchet wheel to rotate in one direction of rotation, a release element which is attached to the other of the relatively movable members so that it is on the lever assembly during the relative movement of the links engages in one direction and thereby the pivoting of the lever arrangement effected in one pivoting direction, as well as having a stop element which is attached to the first-mentioned of the two members that can move relative to one another 409839/0 29 7 -17- brought and is arranged so that it is on the lever assembly for stopping its pivoting movement at a predetermined Place by the trigger element engages, wherein the lever arrangement means to reduce the by a given speed of relative movement between the relatively movable members causing rotational speed of the ratchet wheel during part of the pivoting movement of the lever assembly immediately prior to its engagement with having the stop element. 2ο microtome according to claim 1, characterized in that the lever arrangement has a main lever which carries the pawl and an auxiliary lever which can pivot attached to the main lever for pivoting about an axis parallel to and at a distance from the pivot axis of the main lever and is arranged so that the trigger element engage it at a point on one side of its pivot axis can that resilient biasing devices are provided which between the main lever and the auxiliary lever are connected so that the main lever follows the pivoting movement of the auxiliary lever when the release element is attached to it engages, and that a second stop element is provided which is arranged such that it is on the auxiliary lever at a point on the side of its pivot axis opposite to its point of contact with the release element - 18 409839/0297 engages before the main lever engages the first-mentioned stop element, so that during part of the pivoting movement the lifting arrangement immediately before the engagement of the main lever with the first stop element of the auxiliary lever pivoted relative to the main lever against the spring force of the pretensioning devices and thereby the pivoting speed of the main lever, which is reduced by a given speed of relative movement between the relatively movable Giiedern is effected. 3. Mikrotom'nach claim 2, characterized in that the pawl and the auxiliary lever at respective ends of the main lever on opposite sides of the 'pivot axis of the main lever are attached and that the auxiliary lever is arranged such that the trigger element on a Engages point on the side of the pivot axis of the auxiliary lever, which is arranged away from the pivot axis of the main lever. 4. Microtome according to Claim 2 or 3, characterized in that the resilient tensioning devices are a tension spring have which is connected to one end of the auxiliary lever and a point of the main lever. - 19 - 409839/0297 5. microtome according to one of claims 1 "to 4, characterized in that it is. that the relatively movable members have a base and one supported by and on the base linear "movable carriage, wherein the knife can be supported in a fixed position by the base is that the ratchet is mounted in the carriage and can be actuated for a movement of the object holder supported by the slide, and that the trigger element is attached to the base in such a way that the lever arrangement of the ratchet circuit during the linear Attacking movement of the slide. 409839/0297