GB2145240A - Clamping device for a cutter of a microtome - Google Patents

Abstract

A clamping device for a cutter 1 of a microtome, said cutter 1 having a cutting edge 1', the device defining a cutting region of said cutting edge and comprising clamping means for supporting the cutter adjacent the cutting edge in the cutting region, the clamping means including a first support 6 for supporting the cutter on a first face thereof, and a second support 7 for supporting the cutter on the second face thereof. The supports may form part of a housing 3 and the housing 3 may be pivoted relative to a base 21. <IMAGE>

Description

SPECIFICATION Clamping device for a cutter of a microtome This invention relates to a clamping device for a cutter of a microtome.

A known clamping device for a microtome comprises two screw-threaded bolts with screw heads in a cutter holder. The cutter holders are arranged laterally of a cutting region defined by the device. In such clamping devices, the cutter is clamped rigidly between two lateral supports and since a thinsectioned specimen holder is clamped in the microtome, only a relatively small portion of the cutting edge of the cutter is utilised. The cutter is exposed to a high degree of wear along this small portion, so that the useful life of the cutter is limited. Moreover, the cutting region is limited by the lateral screwthreaded bolts and their screw heads.

It is an object of the present invention to provide a clamping device for a cutter of a microtome which permits the utilisation of the whole cutting edge of a cutter.

According to the present invention there is provided a clamping device for a cutter of a microtome, said cutter having a cutting edge, the device defining a cutting region of said cutting edge and comprising clamping means for supporting the cutter adjacent the cutting edge in the cutting region, the clamping means including a first support for supporting the cutter on a first face thereof, and a second support for supporting the cutter on the second face thereof.

By moving the cutter relative to the supports different cutting regions of the cutting edge can be defined so that the entire length of the cutting edge can be utilised. Furthermore, various kinds of cutters including cutters with varying edge geometries and re-ground cutters with different edge angles can be clamped reliably and in a stable manner.

Preferably, two spaced elements carry the first and second supports, the cutting region being disposed between such elements. By this means a clamping device is provided in which cutters of any desired length can be clamped. It is possible to flamp a cutter which is shorter in length than the distance between the two spaced elements; thus the entire cutting edge of such a short cutter can be used.

Advantageously, adjustable stop means is carried by the first support for supporting the cutter. The adjustable stop means preferably comprises two fine-pitch screw-threaded bolts rotatable in the first support with knurled nuts protruding out of the device. This arrangement facilitates simple and precise positioning of the cutting edge so that, on the one hand problem-free clearance angle adjustment ca be made, and on the other hand alignment of the cutting edge can be adjusted simply and quickly.

In a preferred embodiment of the invention, the second support comprises a jaw which is biassed towards the first support, and said jaw and said first support are both wedge-shaped in cross-section and project towards the cutting edge, so that on the one hand the cutter is reliably clamped adjacent to the cutting edge, and on the other hand cutting operations are not obstructed.

Preferably the jaw comprises two raised portions which engage and locate the cutter against the jaw.

This provides for reliable, firm contact with the cutter irrespective of the particular wedge angle of the cutter.

Advantageously, the clamping device comprises eccentric means for moving the jaw, the eccentric means being mounted for rotation about an axis generally parallel to the cutting edge of the cutter. A particularly easy-to-operate clamping device is thereby provided. Only a single operating element is used for clamping and releasing the cutter, which element is located outside the cutting region. Since the operating elements are easily accessible, it is possible to utilise a relatively large cutting region thereby enabling easy section removal to take place.

Further features and advantages of the invention will be clear from the following description of an example of a clamping device which is illustrated in the drawing, wherein: Figure 1 is a section through the clamping device; Figure2 is an elevation of the clamping device; and Figure 3 is a plan of the clamping device in the direction of the arrow A in Figure 2.

A clamping device comprises a base part 21 and a cutter housing 3 mounted for rotation relative to the base part. A surface of the cutter housing is in face-to-face sliding engagement with a cylindrical surface 2 of the base part. A cutter 1 mounted on the device is located in a space defined by the cutter housing 3 so that a cutting edge 1' of the cutter is colinear with the axis of the sliding surface 2 and of the housing. It is thereby possible, by pivotting the housing 3, to vary the clearance angle of the cutter 1, without otherwise having to change the position of the cutter.

The cutter 1 rests on adjustable stop means in the form of two screw-threaded bolts 5 which are arranged one behind the other, as viewed in Figure 1. The screw-threaded bolts are vertically adjustable by means of knurled nuts 4 which protrude out of the clamping device to enable the cutting edge 1' of the cutter to be precisely levelled.

Clamping means for supporting the cutter 1 on opposite faces thereof and for clamping the cutter comprises a first support which comprises an abut- ment 6 and a second support which comprises a jaw 7. The cutter is stabilised in the region of the cutting edge 1' by the wedge-shaped abutment which extends between two spaced elements 17, and a leading edge portion of which is adjacent to the cutting edge 1'. The leading edge portion of the abutment is disposed behind the cutting edge so as not to obstruct cutting operations.

The wedge-shaped jaw 7 exerts a tensioning force across the entire length of a section removal or cutting region 14-14 extending between the elements 17. The tensioning force is exerted towards the abutment 6. This tensioning force is controlled by means of an eccentric bolt 8, which is mounted in the two elements 17. The bolt is mounted for rotation about a longitudinal axis which extends generally parallel to the cutting edge of the cutter to drive the wedge-shaped jaw 7 slidably between a face of the cutter 1 and a spacer 10 mounted on each support 17. The cutter 1 is thereby clamped.

A face 19 of the jaw 7 defines a recessed surface between two generally rectilinear raised portions extending generally parallel to the cutting edge of the cutter. The raised portions engage the cutter to locate the cutter against the jaw. One of the raised portions defines a leading edge of the jaw, and is disposed adjacent to but behind the cutting edge of the cutter. Compression springs 11 and 12 bias the jaw towards the abutment to ensure that the jaw is brought into engagement with a face of any one of various differently shaped cutters which can be mounted in the device.

The jaw 7 can be retracted so that the cutter 1 is released upon an appropriate rotation of the eccentric bolt 8. The cutter can then be slid in its longitudinal direction, that is to say at right angles to the plane of the drawing in Figure 1, in order to bring afresh hitherto unused portion of the cutting edge 1' into the cutting region of the microtome. The cutter 1 is then once more clamped in the clamping device. If required, the cutting edge 1' can be re-levelled by rotating the knurled nuts 4.

Locking of the cutter housing against pivoting relative to the base part, with the cutter and the cutter housing at a particular clearance angle, is effected by a means comprising a handle 13. As Figures 2 and 3 show, the cutter can be clamped both between the spaced elements 17 and also between the jaw and abutment. The cutter 1 is reliably supported by the jaw 7 and by the abutment 6 which extends between the two supports 17. A means for clamping and releasing the cutter 1 comprises a rotary handle 9.

As the Figures show, neither the handles 9 and 13 nor any other operating elements are present in the proximity of the section removal region 14-14; indeed, this region is further enlarged by obliquely angled surfaces 15 and 16 of the housing. Removal of sections is an easy operation with the clamping device according to the invention.

Claims (12)

1. A clamping device for a cutter of a microtome, said cutter having a cutting edge, the device defining a cutting region of said cutting edge, and comprising clamping means for supporting the cutter adjacent the cutting edge in the cutting region, the clamping means including a first support for supporting the cutter on a first face thereof, and a second support for supporting the cutter on the second face thereof.

2. A clamping device in accordance with Claim 1 in which two spaced elements carry the first and second supports, the cutting region being disposed between said elements.

3. A clamping device in accordance with Claim 2 wherein the first support is fixed relative to the spaced elements and the second support comprises a jaw for clamping the cutter on the first support.

4. A clamping device in accordance with any of Claims 1 to 3 comprising adjustable stop means carried by the first support for supporting the cutter.

5. A clamping device in accordance with Claim 4 wherein the adjustable stop means comprises two fine-pitch screw-threaded bolts which are rotatable in the first support.

6. A clamping device in accordance with Claim 1 wherein the first support is generally wedge-shaped in cross-section and a leading edge portion of the first support is adjacent to the cutting edge of the cutter.

7. A clamping device in accordance with Claim 3 wherein the jaw is generally wedge-shaped in cross-section and a leading edge portion of the jaw is adjacent to the cutting edge of the cutter.

8. A clamping device in accordance with Claim 3 wherein the jaw comprises two raised portions which engage the cutter to locate the cutter against the jaw.

9. A clamping device in accordance with Claim 3 wherein the jaw is movable generally towards and away from the cutting edge of the cutter, and slides on a spacer mounted on each spaced element.

10. Aclamping device in accordance with Claim 9 comprising eccentric means for moving the jaw, the eccentric means being mounted for rotation about an axis generally parallel to the cutting edge of the cutter.

11. A clamping device in accordance with Claim 2 wherein the first and second supports and the spaced elements form part of a housing and the housing is pivotable relative to a base about an axis which is colinear with the cutting edge.

12. A clamping device substantially as herein described with reference to and as shown in the accompanying drawings.