GB2182881A

GB2182881A - A blade holder for a microtome

Info

Publication number: GB2182881A
Application number: GB08627100A
Authority: GB
Inventors: Horst Riegel; Gerhard Pfeifer
Original assignee: Ernst Leitz Wetzlar GmbH
Current assignee: Ernst Leitz Wetzlar GmbH
Priority date: 1985-11-18
Filing date: 1986-11-13
Publication date: 1987-05-28
Also published as: SE8604913L; GB8627100D0; SE8604913D0; DE3540861A1; GB2182881B; SE460994B; DE3540861C2

Abstract

The blade holder comprises a carrier plate (10) and a clamping plate (11), tiltably mounted thereon and movable between blade-release and -clamping positions by means of a rotatable shaft 17. The carrier plate (10) is provided with a groove (27) which extends over its entire length and has an L-shaped cross-section. An abutment strip (28) also of L-shaped cross-section is insertable in different positions into the groove. In this manner, an abutment surface variable in position is provided for the blunt rear edge of a disposable knife blade (12), so that blades of different width can be accommodated. In the blade-release state of the holder, the blade (12) can, in the case of wear at one place, be easily displaced. <IMAGE>

Description

SPECIFICATION A blade holder for a microtome The present invention relates to a bladeholderfora microtome.

In DE-OS 3412250 there is disclosed a clamping device for a cutting blade of a microtome, in which the blade is clampable fast by its rear surface and by itsfrontsurface, lying opposite the rear surface, in a blade receptacle. The blade receptacle comprises a base part, a counterbearing device connectiblewith the base part and a clamping device connected with the base part. The counterbearing device is provided with a recess in which the cutting blade is mounted by part of its rear surface and by its spineopposite the cutting edge. For each cutting blade of different cutting geometry, a respective cou nterbeari ng device with a recess adapted to this geometry is used. The counterbearing device isforthis purpose mounted by means of screws at a wedge surface of the base part.

In DE-Gbm 7 835 there is disclosed a holding device for microtome blades, the device comprising a base plate with a wedge-shaped cross-section and a holding plate, between which a blade can be fixed on a lower surface ofthe base plate. The latter is provided with two grooves which extend parallelly over its entire length and ofwhich one serves as a receptacle and guideforthe holding plateandthe other, by a side wall, as a bearing forthe blunt rear edge ofthe blade. This known device is suitable for the replacement of blades of equal width and thickness, for example from a distributor device.

Described in DE-PS 2140796 is a blade holderfora thin flexible disposable blade of a microtome, which clampsthe blade between afixed supporting surface and an unlatchableclamping part. The disposable blade is a commercially usual scalpel blade with a blunt rear edge opposite the cutting edge. The supporting part of the blade holder has a bearing shoulderforthe rear edge ofthe blade and is provided at both sides with slots for lateral insertion and ejection of the blades. The disposable blades must be of the same width inthisknown blade holder.

There is thus a need for a blade holder with which disposable blades of different width and thickness can be used, exchanged easily and utilised for cutting over the entire length without impairment of precise and secure positioning.

According to the present invention there is provided a blade holder for a microtome, the blade holder comprising a carrier member, a clamping memberwhich is mounted on the carrier memberto clamp a blade thereto with a rear edge of the blade bearing againstan abutmentsurface and which is pivotable relative to the carrier member to release the blade, and an abutment strip arranged in the carrier member in a selectable one of a plurality of different positions providing respectively different positions ofthe abutment surface.

The variable position of the individual abutment surfaces can be achieved by means of a single abutment strip of rectangular cross-section, in which the strip is reset with the aid of threaded pins arranged perpendicularlyto a blunt rear edge ofthe blade.

In a particularly advantageous embodiment, however, the abutment strip has an L-shaped profile and is inserted in different positions in an L-shaped groove extending overthe entire length ofthe carrier member and displaceable in the groove. Magnet means, mounted in the carrier member, can servefor retaining the abutment strip in the groove.

An embodiment of the present invention will now be more particularly described with reference to the accompanying drawings, in which: Figure lisa plan view of a blade holder embodying the invention; Figure2 is a cross-section along the line A-A of Figure 1; and Figures3ato3care sectional views,to an enlarged scale, of parts ofthe holder showing three different arrangements of an abutmentstripthereof.

Referring now to the drawings there is shown a blade holderwhich comprises a carrier plate 10 and a clamping plate 11, between which a disposable cutting blade 12 can be clamped fast in the manner described below. The clamping plate 11 is mounted on the carrier plate 10 by means of an adjusting screw 13 andtiltable aboutthe adjusting screw 13.

Forthis purpose, the clamping plate 11 has a foot-like projection 14which bears on a leaf spring 15. The spring 15 rests on a clamping shaft 17, which has a flat 16, and is settable by means of set screws 18forthe regulation of the clamping force. In place of the shaft 17 with the flat 16, an eccentric shaft can be used forthe movement ofthe clamping plate 11. The shaft 17 lies in a recess 19 of square cross-section and is rotatable, by means of a handle 20, into a clamping position and an unlatching position.The leaf spring 15 in the first position bears on the round part ofthe shaft 17 and in the second position on the flat 16. A clamping arrangement ofthat kind is known.

Arranged between the carrier plate 10 and the clamping plate 11 is a compression spring 21,which, in the unlatching position ofthe shaft 17, raises the clamping plate 11 at the blade side. In this manner, knife blades of small thickness can be inserted frontally into the holder. Additionally, lateral insertion of blades is facilitated. In the case of greater deviations of the blade thickness, an adaptation can be undertaken by means of the adjusting screw 13.

The clampling plate 11 is in one piece and consists of a middle part 22 ofrectangularcross-section and a clamping strip 23, which is wedge-shaped in cross-section and extends on both sides of the middle part 22. The strip 13 is inclined downwardly and engages over an inclined surface 24 ofthe carrier plate lOinthemiddle portion thereof. During clamping ofthe blade 12,thisis pressed by means of a projection 25 at the inside ofthe clamping strip 23 onto a bearing surface 26 of the carrier plate 10, which is slightly curved convexly.

A groove 27 of L-shaped cross-section is milled, parallelly to the bearing surface 26, into the inclined surface 24 of the carrier plate 10 and extends overthe entire length of the plate 10. An abutment strip 28, also of L-shaped cross-section, is insertable into the groove 27 in different ways, as shown in Figures 3a to3c.

In Figure 3a, the abutment strip 28 is inserted into the groove 27 in such a mannerthatthe short limb of the abutmentstrip 28 bears againsttheend ofthe groove 27 facing the bearing surface 26 and projects therefrom. In this manner, a bearing surface F1 is formed by the abutment strip 28 forthe rear edge of a blade 12 of relatively small depth.

In Figure 3b, the arrangement of the abutment strip 28 is such that itsshortlimb is received in a depression 29 ofthe groove 27, the depression resulting from the L-shaped cross-section ofthe groove. One lateral surface of the groove 27 serves as the bearing surface F2 for a blade 12 of relatively great depth, whilstthe planar surface ofthe abutment strip 28 forms an additional bearing forthe blade.

For disposable cutting blades of medium depth, the abutment strip 28 can be inserted as shown in Figure 3c. In this case, the inside edge ofthe short limb ofthe abutment strip 28 forms a bearing surface F3 forthe rear edge ofthe blade, which in turn is carried at its rear portion by the abutment strip 28.

For reasons of strength, the cutting edge ofthe blade may project only by a certain amount A out of the blade holder. As is evident from Figures 3a to 3c, this is maintained, even for different depths of the blade, by the abutment surfaces F1, F2 and F3 determined bythe abutment strip 28 inserted into the carrier plate 10.Theabutmentstrip 28 is displaceable in the groove 27 and held therein by means of magnets30, of which onlyone isshown in Figure 2. In orderto preventtilting ofthe blade 12 away from the abutment strip 28, metal guide plates 31 are mounted on the carrier plate 10 on either side ofthe clamping strip 23 ofthe clamping plate 11. The plates 31 engage over the abutment strip 28 without impairing its displaceabilitywithin the groove 27.

Moreover, cover plates 32 covering the clamping shaft 17 and engaging overthe guide plates 31 are provided on the carrier plate 10 and connected with the latter by screws, the plates 32 being arranged on either side ofthe middle part 22 ofthe clamping plate 11.

The blade holdercan beunlatchedthrough actuation of the handle 20 and appropriate rotation of the clamping shafti7. In that case, the clamping plate 11 is raised by means of the compression spring 21 so that a disposable blade of small thickness is introducible into the holderfrom the front, while blades ofgreaterthickness are pushed in laterally. The abutment strip 28 is previously positioned in the groove 27 according to the width of the blade and the holder is then latched. The displacement of the blade 12 on the bearing surface 26 in the case ofwear ofthe cutting edge at one place is possible, after unlatching the holder, just as easily as an exchange of the blade. The same position of the cutting edge, or size of the dimension A, is ensured through the bearing of the rear edge ofthe blade over its entire length against one ofthe abutmentsurfaces F1, F2 and F3.

Claims

1. Ablade holderfora microtome, the blade holder comprising a carrier member, a clamping member which is mounted on the carrier memberto clamp a blade thereto with a rear edge ofthe blade bearing against an abutment surface and which is pivotable relative to the carrier member to release the blade, and an abutment strip arranged in the carrier member in a selectable one of a plurality of different positions providing respectively different positions ofthe abutment surface.

2. A blade holder as claimed in claim 1 ,wherein the abutmentstrip is arrangedto be movable ion a groove extending in the carrier member between two ends thereof.

3. A blade holder as claimed in claim 2, wherein each ofthe groove and the abutment strip is of L-shaped cross-section.

4. A blade holder as claimed in either claim 2 or claim 3, comprising magnet means holding the abutment strip in the groove.

5. A blade holder as claimed in any one ofthe preceding claims, wherein the clamping member is resiliently mounted on the carrier member.

6. A blade holder as claimed in anyone ofthe preceding claims, comprising a respective guide plate mounted on the carrier member at each of two opposite ends ofthe clamping memberto engage overthe abutment strip.

7. A blade holder substantially as hereinbefore described with reference to the accompanying drawings.

8. A cutting element comprising a blade holder as claimed in any one ofthe preceding claims and clamped to the carrier member by the clamping member.

9. A cutting element as claimed in claim 8 and substantially as hereinbefore described with reference to any one of Figures 3a to 3c ofthe accompanying drawings.