WO2014021728A1

WO2014021728A1 - Rotary microtome with adjustable cutting stroke length

Info

Publication number: WO2014021728A1
Application number: PCT/RU2012/000622
Authority: WO
Inventors: Илья Борисович ИЗВОЗЧИКОВ; Анатолий Иванович КУРАПОВ
Original assignee: Izvozchikov Ilya Borisovitch; Kurapov Anatoliy Ivanovitch
Priority date: 2012-07-30
Filing date: 2012-07-30
Publication date: 2014-02-06

Abstract

The invention relates to laboratory equipment, specifically to microtomes, i.e. devices for producing thin slices of histological or biological samples, and particularly to rotary-type microtomes. The rotary microtome with adjustable cutting stroke length comprises, mounted on a base, a knife holder and guides for a carriage for accommodating a sample holder, said carriage being mounted in said guides so as to be vertically movable, a rotor installed on the base and connected to a crank which is also positioned on the base, parallel to the rotor, the pin of which crank is positioned on a radial slider having a screw drive, and a crank-slider mechanism linking the crank to the sample holder carriage. The crank-slider mechanism of the claimed microtome is in the form of a rocker lever, the rotational axis of which is positioned on the same base, said lever being linked to the sample holder carriage and equipped with a means for compensating the weight of the sample, the sample holder, and the carriage for accommodating the sample. The screw drive of the crank slider has a plate which protrudes beyond the crank disk, and an electric motor is positioned on the base, the shaft of which motor is provided with a bushing having a slot corresponding to the protruding plate of the slider drive.

Description

Rotary microtome with adjustable cutting length

The technical field The invention relates to laboratory equipment, namely to microtomes, that is, devices for producing thin sections of histological or biological samples, and in particular to rotational type microtomes. It can be used in medical and biological laboratories specializing in histological and cytological studies.

State of the art

A rotary microtome typically includes a vertically mounted knife and a carriage with a vertically mounted sample mounted for movement along vertical guides. The movement of the carriage is carried out during the rotation of the rotor associated with the carriage with a crank-link mechanism with a progressively moving link. The mass of the carriage with the sample holder and the sample feed mechanism is compensated by a counterweight eccentrically mounted on the drive rotor. The drive can be manual [NM 325 Manual Rotary Microtome prospectus from Thermo Scientific] or motorized [NM 355S Automatic Rotary Microtome prospectus from Thermo Scientific],

Rotational microtomes have the following advantages:

- the convenience of manufacturing slices due to the vertically located knife;

- the possibility of using auxiliary devices, such as, for example, a conveyor for slices, baths with liquid for straightening slices attached to a knife, a device for transferring slices with a fluid stream, etc .;

- the possibility of using a motorized cutting drive.

The main disadvantage of a rotary microtome is the fixed value of the cutting stroke, which is determined by the radius of the crank. Typically, the size of the cutting stroke is 60 - 70 mm, which makes it possible to produce slices of samples 40 - 50 mm long. At the same time, a significant part of the samples is much smaller - for example, endoscopic biopsies, which are poured into molds 3-5 mm long. In this case, most of the cutting stroke is useless (idle). On the other hand, there are samples whose dimensions exceed 50 mm - for their processing a separate microtome is needed.

Another significant drawback is that when the driving rotor rotates, the counterweight located on it creates a multidirectional moment of inertia, which is greater, the higher the speed of rotation of the rotor. Parasitic moments of inertia occur, under the influence of which the microtome begins to swing on the table during operation. To ensure the stability of the microtome, one has to make it massive (mounted on a massive bed - for example, the mass of the Leica RM2235 base microtome is 29 kg), which increases the metal consumption and makes it difficult to maintain the microtome.

Reducing the size of the cutting stroke can save time in the manufacture of slices of small objects. However, if the cutting stroke is less than 40 mm (the length of a standard cartridge, which is also the sample holder), when the microtome stops, it will be impossible to remove the object from the holder, since part of the cartridge will be behind the knife. If the stroke length is 40 mm, the object replacement procedure is unsafe, as you will have to manipulate in the immediate vicinity of the knife blade.

Thus, the radius of the crank must be changed during the processing of one sample - to reduce during the manufacture of slices to reduce idling and increase for safe change of the object.

Microtomes with a variable crank radius are known in the art.

The rotary microtome (Fank, US20100000390) includes a vertically mounted knife mounted on a massive base and guides of the sample holder carriage mounted in vertical guides, a rotor mounted on the frame with an eccentrically located counterweight and with a crank, the spike of which enters the groove of the holder carriage backstage sample. The crank includes an eccentrically located rotary insert, on which the spike is eccentrically placed. The insert has two fixed positions corresponding to the minimum and maximum radius of the crank and, respectively, the minimum and maximum cutting stroke of the sample carriage. To change the position of the spike, the rotor must be stopped, fixed in position corresponding to the upper position of the carriage of the sample holder, after which the insertion position is changed using a special tool. At the same time, the counterweight should also be changed using a special tool.

The Fank device requires complex readjustments to change the size of the cutting stroke; if you set the cutting length to less than 40 mm (the length of a standard cartridge), the device will have to be re-set twice during the processing of each sample, because when the microtome stops, it will be impossible to remove the object from the holder, since part of the cartridge will be behind the knife. The time spent on readjustment operations exceeds it savings by reducing idle.

The rotor in this system remains unbalanced due to the placement of a counterweight on it, which causes the appearance of multidirectional parasitic moments of inertia during its rotation, and this requires a massive base, ensuring the stability of the microtome.

The rotary microtome according to (Heid WO2012 / 041284) includes a vertically mounted knife mounted on a massive base and guide carriages for placing a sample mounted in the guides with the possibility of vertical movement, a rotor placed on the frame with an eccentrically fixed fixed counterweight and adjustable with an additional counterweight. The rotor is connected to the crank, the spike of which enters the groove in the wings of the carriage of the sample holder. The crank spike is located on a slider that can be moved along radial guides. The slide is moved by means of a screw drive connected by a pair of bevel gears with a shaft passing through the hollow shaft of the rotor, ending with a handle regulating the position of the slide. An adjustable counterweight is mounted to move along radial guides and is driven by the same shaft that changes the position of the slider. The specified movement is carried out using a gear and gear rack or linkage system. By turning the adjusting knob, the radius of the crank and the position of the adjustable counterweight are simultaneously changed; Thus, the magnitude of the cutting stroke can be changed during the processing of one sample without readjustment of the microtome. An additional device that changes the position of the adjustable counterweight greatly complicates the design of the microtome and increases production costs. In addition, in this system, the rotor remains unbalanced, and the multidirectional parasitic moments of inertia during its rotation are preserved, which also requires a massive base, ensuring the stability of the microtome.

A rotational microtome [Kiene, US 5881626, 1999] is devoid of this drawback. It includes a vertically located knife and guide carriages for placing a sample installed in the guides with the possibility of vertical movement, a rotor with a manual drive, a crank mechanism connected with it for moving the carriage, and also a device for balancing (balancing) the mass of movable elements, made in in the form of a vertical lever, one shoulder of which is connected to an adjustable spring, and the other indirectly (indirectly, see paragraph 1 of the formula) is connected to the microtome drive by an element thrown over the roller. The specified element thrown over the roller can only be flexible.

The rotor of the microtome according to US 5881626 is completely balanced, it does not create parasitic moments of inertia when it is rotated, however, the lever, which is indirectly connected to the microtome drive, can only return the carriage with the sample to the upper position, it cannot be used to perform a cutting stroke. The device also does not provide a change in the magnitude of the cutting stroke.

The swinging lever associated with the rotor and crank, providing a cutting course of the microtome, is used in ultramicrotomes [US patents 2822726, 1958; 3,771,405, 1973; 3,828,641, 1974; 4126069, 1978; 7437984, 2008]. The sample holder of the ultra-microtome is fixed at the end of the swinging lever, and cutting is performed along an arc whose radius is determined by the length of the lever. The dimensions of the sample for ultramicrotomy are very small - about 1 mm, - so the curved movement of the sample does not prevent a complete cut. When processing large samples, especially flat ones, the arched movement will allow to obtain a cut of only part of the sample, therefore, when processing such samples, a rectilinear movement of the sample is required. Disclosure of invention

The basis of the invention is the task of creating a rotational microtome with an adjustable cutting length, having a balanced rotor, a fairly simple design, easy to operate and maintain.

The objective of the invention is also to reduce the weight of the microtome and reduce its metal consumption.

According to the invention, a rotary microtome with an adjustable cutting stroke length is proposed, including a holder for a vertically arranged knife mounted on a bed and guide carriages for placing a sample installed in the guides with the possibility of vertical movement, a rotor mounted on the bed, connected with a crank also placed on the bed in parallel a rotor, the spike of which is located on a radial slider with a screw drive, and a crank-link mechanism connecting the crank to the holder carriage the sample, made in the form of a swinging lever, the axis of rotation of which is located on the same frame, the lever is connected to the carriage of the sample holder, equipped with means to compensate for the weight of the sample, sample holder and carriage for placing the sample, the screw drive of the crank slide has a bar protruding beyond the disk the crank, and on the bed there is an electric motor, on the shaft of which a sleeve is made with a slot corresponding to the protruding plate of the slide screw.

As a means of compensating for the weight of the sample, the sample holder and the carriage, a spring can be used placed on the axis of attachment of the lever; as the specified means can be used a counterweight placed on the end of the lever opposite to the sample holder.

The microtome bed is made in the form of a vertical plate.

The connection of the crank with the swinging lever can be made in the form of a spike and a groove, in which the crank spike enters the slot made in the swinging lever. The lever with a longitudinal slot, which includes the crank spike, performs the function of a rocking link.

The connection of the crank with the swinging lever can also be made in the form of a connecting rod connected to the crank spike and the lever. The connection of the lever with the carriage can be made in the form of a finger placed on the carriage of the sample holder, and a groove located at the end of the lever. Such a connection is movable and directly transfers force from the driving rotor to the carriage. Direct connection of the lever with the carriage of the sample holder allows you to control both the return of the carriage to the upper position and the cutting stroke of the microtome.

Declare microtome can be mechanized, and its control is automated.

Brief Description of the Drawings

The inventive device is shown in FIG. fifteen.

Figure 1 presents the microtome with a lever with a slot and a spring as a compensating means.

Figure 2 presents the microtome with a lever with a slot and a counterweight as a compensating means.

Fig. 3 shows a microtome with a lever and a connecting rod, and with a spring as a compensating means.

Figure 4 presents the crank with the slider, part of the lever, the protruding bar of the slider and the adjustment mechanism of the slider.

Figure 5 presents a side view of the crank with a slider, with a crank spike and with a protruding bar, and a sleeve with a slot for adjusting the position of the crank on the slider.

On a vertically mounted frame 1 (see Fig. 1-3), there is a knife holder 2, in which the knife 3 is attached, and guide carriages 4, in which the carriage 5 with the sample holder 6 can be moved in a vertical plane. The sample 7 is fixed in the holder 6. On the same frame 1 is placed a rotor 8 having a handle 9 for manual cutting of the samples. On the opposite side of the frame 1, a crank 10 with a radial slider 1 1 is fixed coaxially with the rotor, on which the spike 12 is placed. The slider is moved using a screw drive 13 (see Figs. 4 and 5). On the frame 1 is located the axis 14 of the lever 15, equipped with a means 16, compensating for the weight of the sample, the sample holder and the carriage. As this means, a spring (Figs. 1 and 3) or a counterweight (Fig. 2) can be used. The lever 15 is movably connected with the carriage 5 of the sample holder with using the finger 17 included in the groove 18 located on the lever. There are other options for direct connection of the lever with the carriage.

The spike 12 of the crank enters the slot 19 in the lever 15 (Figs. 1 and 2).

The screw drive 13 of the slider 1 1 of the crank has a bar 20 protruding beyond the disk of the crank (Figures 4 and 5). The corresponding sleeve with a slot 21 is made on the shaft of the motor 22, also placed on the frame 1. The slot 21 is made so that the strip 20 freely passes through it when the crank is rotated. A sensor 23 is installed on the bed 1, and a mark 24 on the crank to align the strip 20 and the sleeve with the slot 21.

The connection of the crank with the lever can be made in the form of a connecting rod 25 with a hinge 26 (see Fig. 3).

Rotational microtome works as follows.

At the beginning of work, with a locked brake (not shown), the rotor 8 is in the upper position of the cutting stroke, the spike 12 of the crank 10 is in the maximum radius position, while the plate 20 of the slide screw 1 1 is engaged with the slot of the sleeve 21, which is controlled by the sensor 23 and mark 24. The carriage 5 is in this case in the highest position. Sample 7 is placed in the sample holder 6. When the brake is locked (not shown), the position of the crank pin 12 on the screw drive 13 of the slide block is changed using the slide actuator (electric motor 22 rotating the sleeve 21 and the strap 20), and the sample 7 is lowered to the position its lower edge 2-3 mm does not reach the blade of the knife 3, thus limiting the length of the cutting and, accordingly, idling. The brake is unlocked and coarse paraffin sections are removed until the exposed sample is completely exposed. By locking the brake, the microtome is stopped, leaving the crank spike in the same position as when cutting paraffin. Prepare for the manufacture of thin sections (cleaning or replacing the knife). Thin sections are manufactured with the cutting stroke already set.

Upon completion of the manufacture of sample slices, the rotor 8 is moved to the position of the upper point of the cutting stroke and the brake is locked, while the plate 20 of the screw of the slider 1 1 engages with the slot of the sleeve 21, which is controlled by the sensor 23 and the mark 24. The crank spike is moved to the crank at the maximum position radius, while the carriage and sample holder are in topmost position. The processed sample is removed from the holder, a new sample is fixed, during the cutting of which the size of the cutting stroke is set in the same way - with the help of a slider drive (electric motor 22, rotating sleeve 21, and straps 20), the position of the crank pin 12 12 on the screw drive 13 of the slider is changed.

The inventive rotational microtome has the following advantages.

It is possible to quickly adjust the magnitude of the cutting stroke over a wide range.

It is possible to move the object to its highest position for safe replacement when the microtome stops.

The processing time of the samples is reduced by reducing the length of the cutting stroke according to the size of the sample while maintaining the optimal cutting speed. This reduces the idle length. The time savings are greater, the smaller the sample size

5 It is possible to process large samples because of the possibility of increasing the length of the cutting stroke.

You can significantly reduce the weight of the microtome, since the balance of the rotor allows you to abandon the heavy base without loss of stability of the device.

0 The inventive rotary microtome allows you to increase free space in the working area due to the compact placement of elements on a vertical bed and the rejection of a massive base.

Industrial applicability

5

The inventive rotational microtome can be used in laboratories specializing in histological and biological research, in clinics and research institutions.

Claims

CLAIM

1. Rotary microtome with a variable size of the cutting stroke, including a knife holder mounted on the bed and guide carriages for placing the sample holder mounted in the rails with the possibility of vertical movement, a rotor mounted on the bed, connected with a crank, also placed on the bed parallel to the rotor, spike the crank is located on a radial slider with a screw drive, and a crank mechanism connecting the crank to the carriage of the sample holder, characterized in that the crank The th mechanism is made in the form of a swinging lever, the axis of rotation of which is located on the same frame connected to the carriage of the sample holder and equipped with means to compensate for the weight of the sample, sample holder and carriage for placing the sample, the screw drive of the crank slide has a bar protruding beyond the crank disk and on the bed there is an electric motor, on the shaft of which a sleeve is made with a slot corresponding to the protruding plate of the slide screw.

2. The rotational microtome according to claim 1, characterized in that, as a means of compensating for the weight of the sample, the sample holder and the carriage, the microtome includes a spring located on the axis of attachment of the lever.

3.. The rotational microtome according to claim 1, characterized in that, as a means of compensating the weight of the sample, the sample holder and the carriage, the microtome includes a counterweight located on the end of the lever opposite to the sample holder.

4. The rotational microtome according to claim 1, characterized in that the bed of the microtome is made in the form of a vertical plate.

5. The rotational microtome according to claim 1, characterized in that a longitudinal slot is made on the swing arm to accommodate a crank spike.

6. Rotary microtome according to claim 1, characterized in that it contains a connecting rod connected to the crank spike and the lever.