Cutting – With means to convey work relative to tool station – Plural passes of diminishing work piece through tool station
Reexamination Certificate
1997-05-06
2001-04-03
Rachuba, M. (Department: 3724)
Cutting
With means to convey work relative to tool station
Plural passes of diminishing work piece through tool station
C083S915500
Reexamination Certificate
active
06209437
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a microtome for the production of histological sections, particularly of plant and animal tissues, which are intended for microscopic inspection.
2. Discussion of Prior Art
So-called slide microtomes are known from the Soviet Inventor's Certificate SU-783626 or from the Applicant's EP-A1 0 416 354, and have a baseplate with an object carrier and in addition substantially horizontal guides. A knife holder is movably received in the horizontal guides and is provided with a handle. The knife holder moves back and forth, linearly and horizontally, and its motion is coupled with a feed drive of the sample carrier.
Slide microtomes are distinguished by their simple construction and the consequent low price. Moreover they are distinguished, as long as the user follows a sufficient routine, by operation which is not tedious. On the other hand, it is a disadvantage that the removal of the microtome sections is quite complicated. This disadvantage clearly becomes manifest in the latest slide microtomes, which have an electrical drive of the sample feed, such as that offered by the Applicant under the designation “OHM 440”. Indeed, because of the electrical sample feed, the knife holder no longer needs to be moved over the whole length of the guideway in order to cause the sample feed. Instead, it is sufficient to move the knife or the knife holder over a path length which roughly corresponds to the thickness of the sample along the direction of cutting, since the electronics of the sample feed detects the reversal of motion of the knife holder. Thus with small samples, a substantially higher cutting frequency is possible. However, it has been found that the time required for removal of sections limits the cutting frequency.
Moreover, so-called rotary microtomes are known, which are described, for example, in DE-P 33 01 921 or in DE-C1 35 39 138. Such a rotary microtome usually has a baseplate on which a slide with a cutting knife, movable parallel to the baseplate, is received. The slide with the sample carrier is received in a further guide, which is directed substantially perpendicular to the baseplate and consequently permits a motion of the sample carrier perpendicular to the baseplate. The drive of the cutting motion, which runs perpendicular to the baseplate, of the sample carrier takes place by means of a hand crank in the form of a disc with a horizontal axis of rotation.
As regards removal of sections, such rotary microtomes are considerably more user-friendly than slide microtomes, since the sections which are produced are produced in the forward region of the microtome, lie on the back face, inclined forward and downward, of the microtome knife or knife holder, and can be floated off there, for example by the use of a water bath. However, such rotary microtomes have the disadvantage that the rotary motion of the handle is quite tiring. The number of sections produced during the course of a working day is thus lower for rotary microtomes than for slide microtomes.
It would be conceivable to provide a motor to drive the cutting motion, in order to eliminate this disadvantage. However, the motors which would be required for this would nearly double the price of the microtome.
SUMMARY OF THE INVENTION
The invention therefore has as its object to provide a microtome with a hand drive for the cutting motion, which microtome is not very tiring to operate, and at the same time enables the sections which are produced to be easily removed.
This object is attained by a microtome having a first linear guide, a sample carrier movable in a guide direction along the first linear guide, a hand drive movable along a substantially linear path of motion substantially perpendicular to the guide direction of the first linear guide and a deflecting device for deflecting motion of the hand drive into motion in the guide direction of the first linear guide.
The microtome according to the invention has a sample carrier which is movable along a first linear guide. Moreover, the microtome has a hand drive which is movable along a substantially linear path of motion, wherein the path of motion of the hand drive is substantially perpendicular to the direction of motion of the sample carrier. Furthermore, means are provided to deflect the motion of the hand drive into a motion in the direction of the linear guide of the sample carrier.
By the deflection of the paths of motion between the hand drive and the sample holder, the motion of the hand drive can take place substantially horizontally forward and backward of the microtome (push and pull motion by the operator), which is considered to be particularly favorable from the ergonomic viewpoint, and can be converted into a motion of the sample carrier, substantially perpendicular to the motion of the hand drive. The cutting motion can thus take place in a substantially vertical direction, so that the sections which are produced can be removed or washed away from the inclined back surface of the cutting knife or knife carrier.
The result of the invention is a microtome which unites the respective specific advantages of both the slide microtome and the rotary microtome, without having the specific disadvantages of each of these types of construction.
The means for deflection of the motion can be constructed, in a simple embodiment example, as a belt drive which is guided over several deflecting rollers. Of course, a belt drive makes possible only an integer transmission ratio between the motion of the hand drive and that of the sample carrier. A counterweight is to be provided, for weight equalization, on the driving belt of the belt drive, having a mass which corresponds to the transmission ratio and to the mass of the sample carrier including its guide slide, chosen such that the two masses equalize each other in each position of the sample carrier.
Alternatively to this, the means for deflection of the direction of motion can be constructed as a plate in the form of a circular segment, or as a lever arm. According to the ratio of the two arm lengths of the lever arm, or according to the ratio of the distances of the deflection points from the mounting point of the circular segment shaped plate, different, and even non-integral, transmission ratios can be set in this embodiment between the motion of the hand drive and that of the sample carrier. The use of a hydraulic system for the deflection of the motions likewise makes possible optional, even non-integral, transmission ratios.
In an advantageous embodiment example of the invention, a device is provided for the detection of a reversal of motion of the sample carrier. By the detection of the reversal of motion, control of the forward feed of the sample can take place independently of the path lengths of the cutting motion. The path length of the sample carrier can be chosen by the user himself, corresponding to the thickness of the sample which is about to be cut, and does not need to pass, in order to release the feeding of the return stroke, along a minimum path which is determined by the construction.
The detection of the reversal of motion is particularly advantageous in connection with a motor drive for the sample feed, and with an electronic control circuit which controls the motor in the case that a reversal of motion is detected.
In a further advantageous embodiment example, a hand drive is provided, or a hand drive can be installed, on two mutually opposite sides of the microtome. The ergonomic advantages of the microtome according to the invention can thus be fully realized for both left-handed and right-handed persons.
Furthermore, in the microtome according to the invention, the knife carrier of the microtome is to be movable, for the sample feed, along linear guideways perpendicular to the cutting motion of the sample holder. The masses to be accelerated during the cutting motion can thus be kept to a minimum, since the mechanism for the sample feed does not count as part of the masses to be accelerated
Heid Hans
Izvoztchikov Ilia
Micron Laborgerate GmbH
Pryor Sean
Rachuba M.
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