FR2529676A1 - MICROTOME HAVING MEANS ADAPTED IN ADVANCE OF THE SPECIMEN CARRIER ARM AND / OR KNIFE - Google Patents

Abstract

PRE-SELECTORS 8, 9 ARE PROVIDED FOR ALLOWING, BY MEANS OF A SWITCH 10, TO SELECT THE NUMBER OF PULSES 7 SENT TO A STEP MOTOR 5 TO ACTUATE IT AND ADVANCE THE SHAFT CARRIING SPECIMEN 2 OF A NUMBER OF STEPS IN DIRECTION OF KNIFE 4, OR THE REVERSE. THIS PROVISION ALLOWS EASILY MODIFICATION OF THE THICKNESS OF CUTS MADE WITH UTRAMICROTOMA.

Description

The present invention relates to a microtome having a control system

  of the specimen carrying arm and / or the knife, and is particularly applicable to

an ultramicrotome.

  To adjust the slice thickness of thin sections that are produced by means of a microtome, the specimen carrying arm, carrying the preparation or specimen, is moved towards the knife before each cutting stroke for a distance corresponding to the thickness of the section In a known ultramicrotome, this operation is carried out by means of an advance mechanism. It is desirable to be able to make an ultramicrotome produce cutting thicknesses which differ from one another by several orders of magnitude. so that, for example, when starting to cut a preparation block, considerably thicker sections can be removed until an area of interest to be thin-cut is achieved. In a known ultramicrotome, it is provided that for this purpose, two pre-selection switches which allow the cutting thickness to be set at different values for the adjustment of the advance In a device of this type, one of the pre-selection switches sets the desired advance for the ultra-thin cuts while the other pre-selection switch sets the advance for the initial cut procedure when one reaches the surface of cut that produces the first usable thin cut, we put on the off position the pre-selection switch which defines the amplitude of the advance for the initial cutting procedure and the ultramicrotome starts to work with the amplitude of which corresponds to the thickness required for

ultra-thin cuts.

  During the production of ultra-thin cuts, it is frequently desirable to produce a number of semi-thin cuts, or it is necessary to get rid of unusable parts of the preparation and, for this purpose,

  increases the amplitude of advance In the case of ultramicro-

  known volume, it requires to redo pass the first -2- pre-selection switch on the running position This

  operation is inconvenient, especially during the

  deliberate cutting of some semi-thin cuts, not only because of the time required for the operation of the switch, but also because the operator is distracted from the operations that take place on the preparation so that

  that it is difficult to exclude the possibility of errors.

  The object of the present invention is to provide an advance control system of the aforementioned type which makes it possible to quickly select different amplitudes of advance, without hindering the work in progress and the ease with which

  the cutting operation can be observed.

  According to one of these aspects, the invention provides a microtome comprising a specimen-carrying arm to be cut, a knife for making cuts from said specimen, driving means for animating the specimen carrying arm with a movement of a specimen. and comes so that said arm moves in a cutting stroke along the knife and in a return stroke, and advancing means for advancing step by step the specimen carrying arm in the direction of the knife before each stroke of cutting, the advancing means comprising a stepping motor, translational drive means for transmitting the movement produced by the stepping motor in linear motion to the specimen carrying arm, a pulse generator joined to the motor not step to send electrical pulses and actuate it, an electrical circuit adapted to provide two or more alternating power outputs, and selector means mounted between the electrical circuit and the pulse generator for joining the one of the outputs selected to the pulse generator, whereby the specimen carrying arm can advance one step having a selected amplitude between two different amplitudes or

  more before each cutting stroke.

  According to another aspect of the invention, the advancing means moves the knife instead of the specimen-carrying arm or moves the knife and the specimen-carrying arm. The various desired advance values can be set and remain set by the different pre-selection switches, these values normally differing by orders of magnitude. If, for example, it is desired to include a number of semi-thin sections during production. of ultra-thin sections, the operator only needs

  set the desired amount of advance at the level of the interrup-

  pre-selection, after which it can go from the ultra-thin cutting thickness to the semi-thin cutting thickness by means of a single manual action at the switching switch. necessary then to find the desired thickness for the cut or the

  set at the pre-selection switch -

  It is convenient to use pre-set switches

  digital type setting as pre-selection switches.

  In one embodiment of the invention, two stepper motors are provided, one of which is connected to the specimen carrying arm and the other of which is connected to the knife support, a pre-selection switch corresponding to each of the

mobs step by step.

  Other advantages and characteristics of the invention

  will emerge from the following description of a form

  embodiment given by way of example with reference to the accompanying drawings in which Figure 1 shows a purely schematic side view of an ultramicrotome, partially in section, and Figure 2 shows an advanced control system.

  employed in the ultramicrotome of Figure 1.

  The ultramicrotome shown in FIG. 1 comprises a specimen holder 1 which is attached to the specimen carrying arm 2 and which carries at its front end a specimen or preparation 3. A training device, which is not shown in such a way. In more detail, guides the specimen carrying arm 2, and thus the specimen holder 1 and the preparation, along a knife 4. In addition, an advance device, which is not shown in FIG. detail, move the portieur arm of specimen 2 towards

  of the knife 4 according to a pre-selection advance amplitude.

  so that thin sections of pre-determinable thickness can be produced at each cutting stroke. The design of the devices driving the specimen carrying arm and the operating mode of the

  the ultramicrotome does not differ from those of

  known volumes and therefore will not be described in detail.

  The control system of the advance device represents

  schematically in FIG. 2 makes it possible to control the amplitude of the advance of the specimen carrying arm 2 for this purpose; the specimen carrying arm 2 is coupled with a stepping motor 5 by means of a translation drive which is not shown in detail. The stepping motor 5 receives electrical pulses 7 which are supplied via a stage. output port 6 enclosing a pulse generator The specimen carrying arm 2 is advanced by a defined number of steps corresponding to the number of pulses The total number of steps corresponds, in each

  case, at the amplitude of advance of the specimen carrying arm 2.

  Digital pre-setting switches 8 and 9 are provided for presetting advance values of different magnitudes, which pre-setting switches may be

  alternatively joined to the power output stage 6.

  The desired thickness of the ultra-thin sections is, for example, set by the pre-selector 8 and a semi-thin section thickness is set by the pre-selector 9, the latter being designed for can be put into action during operation

  the operator of the microtome is sufficient to manipulate the

  10 to set an amplitude of advance, at the level of the stepper motor 5, which differs from an order of magnitude, by

  example of ten times, the thickness of ultra-thin cuts.

  One embodiment of the invention comprises a series of pre-selectors of the aforementioned type adapted to set a series of forward amplitudes instead of the digital pre-selectors ii 8 and 9 shown in the embodiment, this which allows, for example, to select a further cut thickness

  larger for the initial cut operation.

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Claims (4)

  1 Microtome comprising a specimen-carrying arm to be cut, a knife for making cuts from said specimen, driving means for animating the specimen-carrying arm in a back and forth motion so that said arm moves according to a cutting stroke along the knife and in a return stroke, and advancing means for advancing step by step the specimen carrying arm in the direction of the knife before each stroke of   characterized in that the advancing means comprise   a stepping motor (5), translational drive means for transmitting the movement produced by the stepping motor (5) in linear motion to the specimen carrying arm (2), a pulse generator (6), ) connected to the stepper motor (5) to send electrical pulses and actuate it, an electric circuit adapted to provide two or more alternating power outputs, and selector means mounted between said electrical circuit and the pulse generator (6) to join those of the selected outputs (8 and 9) to the pulse generator (6), whereby the specimen carrying arm (2) can advance one step having a selected amplitude between two amplitudes   different or more before each cutting stroke.   2 Microtome comprising a specimen-carrying arm to be cut, a knife for making cuts from said specimen, driving means for animating the specimen-carrying arm in a back and forth motion such that said arm moves in a cutting stroke along the knife and in a return stroke, and advancing means for advancing step by step the knife towards the specimen carrying arm before each run of   characterized in that the advancing means comprise   a stepping motor (5), translational drive means for transmitting the motion produced by the stepper motor (5) in linear motion to the knife (4), a pulse generator (6) joined to the stepper motor (5) -7- for sending electrical pulses and actuating it, an electric circuit adapted to supply two or more alternating power outputs, and selector means mounted between said electrical circuit and the pulse generator sions (6) to join those of the selected outputs (8 and 9) to the pulse generator (6), whereby the knife (4) can advance one step having a selected amplitude between two or more different amplitudes before each cut race.   Microtome according to Claim 1 or 2, characterized in that the electrical circuit comprises a pre-selector associated respectively with each of the said outputs (8 and 9).   whereby the power output can be adjusted.   Microtome according to Claim 3, characterized in that the preselectors (8 and 9) are digital presets.