Hydraulically-operated micromanipulator apparatus

Abstract: A hydraulically-operated micromanipulator apparatus is disclosed. The micromanipulator apparatus comprises: a micromanipulator fine control unit including an operating-side piston finely movable with respect to an operating-side hydraulic cylinder and fine control means, either the operating-side piston or the operating-side hydraulic cylinder being stationarily retained, while the rest being finely operable by the fine control means; a hydraulically-operated micromanipulator including an actuating-side piston finely movable with respect to an actuating-side hydraulic cylinder and a fine displacement member, the actuating-side hydraulic cylinder being connected to said operating-side hydraulic cylinder through a hose, either the actuating-side piston or the actuating-side hydraulic cylinder being stationarily retained, while the rest being attached to the fine displacement member; and compensating means for compensating a pressure change of the hydraulic fluid between said operating-side hydraulic cylinder and said actuating-side hydraulic cylinder when ambient temperature changes.

Description: Background of the Invention Field of the Invention The present invention relates to hydraulically-operated micromanipulator apparatus including microtools, such as a glass electrode positioned in the field of a microscope with the use of hydraulically-operated remote controlling means. Prior Art In basic medical science or biotechnology, micromanipulators are used for treating cells, such as creature's organs, cellular textures, egg cells and the like. These cells are treated in various operations for example suctioning, injecting and dividing by finely controlling a microtool in the field of a microscope. However, when an operator finely controls the micromanipulator by his direct contact with its control handle, his hand trembling may be multiplied and transmitted to the microtool through the body frame. For this reason, care should be taken for finely controlling the micromanipulator. Since the micromanipulator needs to be gently operated without hand trembling, delicate operations, the greatest possible care and a lot of skills are required. In view of these difficulties, a various hydraulically-operated micromanipulators have been proposed for finely controlling the microtool by remote controlling means. These micromanipulators are controlled by hydraulic fluid, such as hydraulic oil. Referring now to Fig.1, a conventional cell treatment device comprising a stage 303 for mounting a Petri dish 302 containing therein egg cells 301 dipped in a reagent, a fixed retaining unit 304 for stationary retaining the cells 301, a micromanipulator 305 for carrying out a practical cell treatment, and an optical system 306 for observing images of the cells 301 irradiated with light. The cell treatment device is operated on a vibration-proof mat 307. The micromanipulator 305 is attached with various kinds of microtools 308, such as a glass electrode for the corresponding cell treatments and includes a three dimensional displacement mechanism for moving the tip end of the microtool 308 in three dimensions. The three dimensional displacement mechanism is finely operated by hydraulic pressure through a joystick 309. The joystick 309 comprises a control handle 311 downwardly extending from the distal end of a visor-shaped supporting frame 310 and a transmitting unit 313 for transmitting the two directional movement 312 of the control handle 311 shown by the arrows through hydraulic pressure. The control handle 311 is provided with a converting unit 314 for converting the two directional movement of the control handle 311 into a mechanical displacement in a horizontal plane. The converting unit 314 connects the supporting frame 310 and the control handle 311. For the vertical movement of the cells to be treated, another mechanism may be provided at an adjacent position of the joystick 309. In other conventional device, the control handle extends upwardly from the converting unit 314. However, since the operator can operate the device at a lower position without raising his arm, the former type, i.e., the micromanipulator with downwardly extending control handle has been widely used. However, in micromanipulators operable by hydraulic pressure, such as oil pressure or water pressure, when ambient temperature changes, the volume of hydraulic fluid may also change. This leads to drift of the tip end of the microtool, and hence accurate observation or operation is not achieved. Other electrically-operable micromanipulator is also known. However, in such micromanipulator, the tip end of the microtool drifts when it is subject to electric hindrance. The problem relates to drift, therefore, remain unsolved. Such problems are serious when a long period of observation or operation is carried out while the tip end of the microtool is abutting to a sample. When drift occurs, the tip end of the microtool moves off from the sample, and hence the observation or operation is interrupted. US 4679976 discloses a conventional micromanipulator apparatus having a single hydraulic closed circuit for X, Y and Z-axis displacement respectively, such apparatus suffering from a drift of the microtool when the ambient temperature changes. US 4946329 discloses a mechanism for compensating for thermal expansion and contraction of fluid in the hydraulic control system of a micromanipulator, the compensating mechanism being connected to a micromanipulator of the single closed hydraulic circuit type such as disclosed in US 4679976. With the foregoing drawbacks in view, the present invention seeks to provide micromanipulator apparatus, which are hydraulically-operable by remote controlling means and include means for compensating drift of the microtool due to a temperature change. Summary of the Invention According to the present invention, there is provided a hydraulically-operated micromanipulator apparatus, which comprises a first operating-side piston and a first operating-side hydraulic cylinder operatively related to each other and finely movable relative to one another in response to movement of a fine control device, one of the first operating-side hydraulic cylinder and the first operating-side piston being stationarily retained, a first actuating-side piston and a first actuating-side hydraulic cylinder operatively related to each other and finely movable relative to one another, the first actuating-side hydraulic cylinder being connected to the first operating-side hydraulic cylinder through a hose so as to form a first closed hydraulic circuit, one of the first actuating-side piston and the first actuating-side hydraulic cylinder being stationarily retained, the non-retained actuating-side piston or cylinder being attached to a fine displacement member, the first closed hydraulic circuit being filled with hydraulic fluid, and a compensating means for preventing expansion and contraction of hydraulic fluid within the first closed hydraulic circuit when the ambient temperature changes, characterised in that said compensating means forms another second closed hydraulic circuit similar to the first closed hydraulic circuit and includes a second operating-side piston and a second operating-side hydraulic cylinder, one of the second operating-side piston and the second operating-side hydraulic cylinder being stationarily retained, the first non-retained operating side piston or cylinder being in opposing relation to the second non-retained operating side piston or cylinder, a second actuating-side piston and a second actuating-side hydraulic cylinder, one of the second actuating-side piston and the second actuating-side hydraulic cylinder being stationarily retained, the second non-retained actuating-side piston or cylinder being attached to the fine displacement member (63), and the first non-retained actuating-side piston or cylinder being in opposing relation to the second non-retained actuating side piston or cylinder, a hose connecting the second actuating-side hydraulic cylinder and the second operating-side hydraulic cylinder, the second closed hydraulic circuit being filled with hydraulic fluid, and further characterised in that said second closed hydraulic circuit cooperates with said first closed hydraulic circuit, the arrangement being such that, in operation, each non-retained operating-side piston or cylinder is displaced by said fine control device for changing the volume of hydraulic fluid within the respective operating-side hydraulic cylinder, and each non-retained actuating-side piston or cylinder is displaced with respect to its operatively related stationarily retained actuating-side hydraulic cylinder or piston wwhen the volume changes of said operating-side hydraulic cylinders are transmitted through the hoses to said actuating-side hydraulic cylinders. Preferably the volume of hydraulic fluid between said first operating-side hydraulic cylinder and said first actuating-side hydraulic cylinder is substantially the same as that of hydraulic fluid between said second operating-side hydraulic cylinder and said second actuating-side hydraulic cylinder. Said first operating-side piston and said second operating-side hydraulic cylinder may be stationarily retained, while said first operating-side hydraulic cylinder and said second operating-side piston may be movable, and wherein the non-retained operating-side hydraulic cylinder and the non-retained operating-side piston may be finely operable by said fine control device. Said first actuating-side piston and said second actuating-side hydraulic cylinder may be stationarily retained, while said first actuating-side hydraulic cylinder and said second actuating-side piston may be movable, and wherein the non-retained actuating-side hydraulic cylinder and the non-retained actuating-side piston may be attached to said fine displacement member. Preferably the volume of hydraulic fluid within said first operating-side hydraulic cylinder is reduced when the volume of hydraulic fluid within said second operating-side hydraulic cylinder is increased, and the volume of the hydraulic fluid within said first operating side hydraulic cylinder is increased when the volume of the hydraulic fluid within said second operating-side hydraulic cylinder is reduced. The micromanipulator fine control unit may provide three-directional fine displacement of the hydraulically-operated micromanipulator. Brief Description of the Drawings Fig. 1 is an explanatory view schematically showing a conventional cell treatment device. Fig. 2 is a perspective view showing a first embodiment of a hydraulically-operated micromanipulator apparatus according to the present invention. Fig. 3 is a perspective view showing an X-axis fine control mechanism of a micromanipulator fine control unit according to the first embodiment of the invention. Fig. 4 is an exploded perspective view showing the X-axis fine control mechanism of Fig. 3. Fig. 5 is a perspective view showing an X-axis fine displacement mechanism of a micromanipulator according to first embodiment of the invention. Fig. 6 is an exploded perspective view showing the X-axis fine displacement mechanism of Fig. 5. Fig. 7 is a sectional view taken along the line I-I of Fig. 5. Fig. 8 is a table for the result of a comparative test, in which the relation between temperature change and amount of drift is shown for the inventive and a conventional hydraulically-operated micromanipulator apparatus. Fig. 9 is an exploded perspective view showing a modified embodiment of the X-axis fine control mechanism. Preferred Embodiments of the Invention The present invention will be described with reference to three preferred embodiments. Although the term "hydraulically-operated micromanipulator apparatus" is herein used as an apparatus operable by oil pressure, it also includes an apparatus operable by water pressure of other fluid pressure. Referring now to Fig. 2, a first embodiment of a hydraulically-operated micromanipulator apparatus according to the present invention is shown, in which the micromanipulator apparatus 1 comprises a micromanipulator fine control unit 2 having handles for three-directional control and a hydraulically-operated micromanipulator 3. The micromanipulator fine control unit 2 is connected to the hydraulically-operated micromanipulator 3 (hereinafter referred to as a micromanipulator) through a plurality of hoses 47, 48, 57, 58, 59, 60. The micromanipulator 3 is fixed to a mounting bar 6 which is supported to a pole 5. A tightening device 7 is mounted on the micromanipulator 3 for supporting a holder 8. A microtool 9 is attached to the front end of the holder 8. A micromanipulator fine control unit 2 has a base plate 11 to which is mounted four side plates 13, 14, 15, 16 and a top plate 17. The base plate 11, the four side plates 13, 14, 15, 16 and the top plate 17 are fixed to each other, thereby providing a case 18. The micromanipulator fine control unit 2 includes an X-axis fine control mechanism 50 for finely displacing the microtool 9 to the X-axis directions, i.e. right-and-left directions. As shown in Figs.3 and 4, the side plate 13 is centrally provided with a through opening 13a through which the front portion of a bearing metal 21 is fitted. The bearing metal 21 is fitted within a ring 22, which is fixed to the side plate 13 by a plurality of bolts 23. The bearing metal 21 has a central through-opening for receiving an X-axis fine control screw shaft 25. The X-axis fine control screw shaft 25 comprises a fine control male thread 25a, a stem portion 25b having reduced diameter and received in the central through-opening of the bearing metal 21, and a fixing male thread 25c provided at one end of the stem portion 25b remote from the fine control male thread 25a. An X-axis fine control handle 26 is rotatably fitted over the ring 22. The X-axis fine control handle 26 has a cylindrical shape, one end of which is open for receiving therein the ring 22. The closed end of the X-axis fine control handle 26 forms a knurled head. The fixing male thread 25c threadly engages with a central threaded through-opening of the control handle 26 and further with a fixing nut 27. The X-axis fine control handle 26 is thus fixed to the X-axis fine control screw shaft 25. An outer slider 30 as a basement has a pair of guiding grooves 30a for receiving an inner slider 31 as a sliding table through a non-shown linear-way bearing. The inner slider 31 is provided at the tailing end with a threaded opening 31a for the engagement with the fine control male thread 25a of the X-axis fine control screw shaft 25. At one end of the outer slider 30, a side plate member 33 is fixed by a plurality of bolts 35, while the other end is mounted to the side plate 13 of the case 18 by a plurality of bolts 36. A first piston 37 is extending from the inner end of the side plate member 33, and a second piston 38 is extending from the inner end of the side plate 13. Mounted centrally on the top surface of the inner slider is a central plate 40 so as to separate the top surface into two halves. A first hydraulic cylinder 41 and a second hydraulic cylinder 42 are mounted on the respective halves by cylinder fixing elements 44, 45 with their openings facing outwardly to the respective pistons 37, 38. Each hydraulic cylinder 41, 42 is provided at its outer periphery with a collar 41a, 42a for the abutting engagement with the cylinder fixing element 44, 45 and at its closed inner side with a hose coupling 41b, 42b for connecting one end of a hose 47, 48. The hose 47 as a first hose connects the first hydraulic cylinder 41 and an X-axis hydraulic cylinder 76 hereinafter described. The hose 48 as a second hose connects the second hydraulic cylinder 42 and an X-axis hydraulic cylinder 75 hereinafter described. The piston 37 is inserted within the hydraulic cylinder 41 so as to provide an oil chamber 41', and the piston 38 is inserted within the hydraulic cylinder 42 so as to provide an oil chamber 42'. The X-axis fine control mechanism 50 comprises the X-axis fine control handle 26, the X-axis fine control screw shaft 25, the bearing metal 21, the ring 22, the outer slider 30, the inner slider 31, the hydraulic cylinders 41, 42 and the pistons 37, 38. In the X-axis fine control mechanism 50, the X-axis fine control screw shaft 25 is rotated when an operator moves the X-axis fine control handle 26. Since the fine control male thread 25a of the X-axis fine control screw shaft 25 is fixed to the inner slider 31, the volumes of the oil chambers 41', 42' are changed by the displacement of the inner slider 31 when the X-axis fine control handle 26 is rotated. As shown in Fig.2, the micromanipulator fine control unit 2 also includes a Y-axis fine control mechanism 51 for fore-and-aft movement and a Z-axis fine control mechanism 52 for up-and-down movement. The Y-axis fine control mechanism 51 and the Z-axis fine control mechanism 52 are substantially the same construction as the X-axis fine control mechanism 50. When the Y-axis fine control handle 54 is rotated, a non-shown inner slider fixed to a Y-axis fine control screw shaft (not shown) slides within a non-shown outer slider, thereby changing the volumes of a pair of oil chambers. These volume changes are transmitted to a pair of non-shown Y-axis hydraulic cylinders of the micromanipulator 3 through a pair of hoses 57, 58. When the Z-axis fine control handle 55 is rotated, a non-shown inner slider fixed to a Z-axis fine control screw shaft (not shown) slides within a non-shown outer slider, thereby changing the volumes of a pair of oil chambers. These volume changes are transmitted to a pair of non-shown Z-axis hydraulic cylinders through a pair of hoses 59, 60. As shown in Figs. 5 to 7, an X-axis fine displacement mechanism 80 of the micromanipulator 3 includes an X-axis outer slider 63 as a fine displacement member provided with a pair of inner guiding grooves 63a. An X-axis inner slider 65 is slidably mounted within the outer slider 63 through a non-shown linear-way bearing. The X-axis inner slider 65 is stationarily retained, while the X-axis outer slider 63 is slidable with respect to the X-axis inner slider 65. At one end of the X-axis inner slider 65, a side plate member 66 is fixed by a plurality of bolts 67, while at the other end thereof a side plate member 69 is fixed by a plurality of bolts 70. The side plate member 66 is provided with an inwardly extending fourth piston 71, and the side plate member 69 is provided with an inwardly extending third piston 72. Mounted centrally on the top surface of the X-axis outer slider 63 is a central plate 74 so as to separate the top surface into two halves. An X-axis hydraulic cylinder 75 as a fourth hydraulic cylinder and an X-axis hydraulic cylinder 76 as a third hydraulic cylinder are mounted on the respective halves by cylinder fixing elements 78, 79 with their openings facing outwardly to the respective pistons 71, 72. Each X-axis hydraulic cylinder 75, 76 is provided at its outer periphery with a collar 75a, 76a for the abutting engagement with the cylinder fixing element 78, 79 and at its closed inner side with a hose coupling 75b, 76b for connecting the other end of the hose 48, 47. The piston 71 is inserted within the X-axis hydraulic cylinder 75 so as to provide an oil chamber 75', and the piston 72 is inserted within the X-axis hydraulic cylinder 76 so as to provide an oil chamber 76'. The X-axis fine displacement mechanism 80 comprises the hoses 47, 48, the X-axis outer slider 63, the X-axis inner slider 65, the X-axis hydraulic cylinders 75, 76 and the pistons 71, 72. In this embodiment, the oil chamber 41' of the first hydraulic cylinder 41, the hose 47 and the oil chamber 76' of the X-axis hydraulic cylinder 76 provides a hydraulic closed circuit (hereinafter referred to as a first hydraulic closed circuit), while the oil chamber 42' of the second hydraulic cylinder 42, the hose 48 and the oil chamber 75' of the X-axis hydraulic cylinder 75 provides a hydraulic closed circuit (hereinafter referred to as a second hydraulic closed circuit). With the provision of such first and second hydraulic closed circuits, one hydraulic closed circuit functions as restricting means for restricting a volume change of the other closed circuit. Referring to Figs.3 and 5, manner of operation of the hydraulically-operated micromanipulator apparatus will be described. Since the subject matter of the present invention is mainly related to drift-prevention, the mechanism thereof will be also described. The first hydraulic closed circuit and the second hydraulic closed circuit include the oil chambers 41', 42' at the operating-side of the micromanipulator apparatus and the oil chambers 76', 75' at the actuating-side of the micromanipulator apparatus. When ambient temperature changes, hydraulic fluid in the respective chambers 41', 42', 76', 75' changes its volume. However, at the operating-side for example; the oil chambers 41', 42' are kept under the same condition, thereby the hydraulic fluid in one oil chamber causes the same expansion or contraction with the hydraulic fluid in the other oil chamber. In this embodiment, since the oil chambers 41', 42' are provided on the common inner slider 31 in opposing relation to each other, the volume change in one oil chamber is restricted by the hydraulic fluid in the other oil chamber. Such restriction occurs also to the actuating-side of the micromanipulator apparatus. Since the oil chambers 76', 75' are provided on the common X-axis outer slider 63 in opposing relation to each other, the volume change in one oil chamber is restricted by the hydraulic fluid in the other oil chamber. With such arrangement of the two hydraulic closed circuits, a volume change of hydraulic fluid is restricted, thereby drift of the microtool 9 fixed to the X-axis outer slider 63 can be prevented. When operating the hydraulically-operated micromanipulator apparatus, an operator holds the knurled head of the X-axis fine control handle 26 provided at the micromanipulator fine control unit 2 and rotates it to the clockwise direction. The rotational movement of the knurled head is transmitted to the fine control male thread 25a of the X-axis fine control screw shaft 25. Since the fine control male thread 25a threadly engages with the internal thread 31a of the inner slider 31, the inner slider 31 is finely displaced by this rotation to the direction shown by the arrow A of Fig.3. The hydraulic cylinders 41, 42 are also finely displaced by this rotation so that the oil chamber 41' becomes narrower and the oil chamber 42' becomes wider. When the volume of the oil chamber 41' is reduced, hydraulic fluid is flown out from the oil chamber 41'. The hydraulic fluid from the oil chamber 41' is then flown through the hose 47 into the oil chamber 76' of the X-axis hydraulic cylinder 76 against some resistance of the piston 72. Therefore, at the micromanipulator 3, the X-axis outer slider 63 of the X-axis fine displacement mechanism 80 is finely displaced toward the side plate member 66 (shown by the arrow A of Fig.4). Since the microtool 9 is mounted on the X-axis outer slider 63 by the tightening device 7, the microtool 9 is finely displaced together with the X-axis outer slider 63. With the displacement of the X-axis outer slider 63, the volume of the oil chamber 75' is reduced and hydraulic fluid is flown out from the oil chamber 75'. The hydraulic fluid from the oil chamber 75' is then flown through the hose 48 into the increased oil chamber 42' of the X-axis fine control mechanism 50. As described above, when the X-axis fine control handle 26 of the micromanipulator fine control unit 2 is rotated to move the inner slider 31 to the direction shown by the arrow A (left-hand direction), the X-axis outer slider 63 of the micromanipulator 3 is moved to the direction shown by the arrow A (left-hand direction). In this operation, the first hydraulic closed circuit functions as part of the micromanipulator fine control unit and the hydraulically-operated micromanipulator, while the second hydraulic closed circuit functions as restricting means. When the X-axis fine control handle 26 of the micromanipulator fine control unit 2 is rotated to move the inner slider 31 to the direction shown by the arrow B (right-hand direction), the hydraulic cylinders 41, 42 mounted on the inner slider 31 are moved to the direction shown by the arrow B. By this movement of the inner slider 31, the volume of the oil chamber 42' is reduced, while the volume of the oil chamber 41' is increased. Hydraulic fluid is then flown out from the reduced oil chamber 42' and it is flown through the hose 48 into the X-axis hydraulic cylinder 75 of the micromanipulator 3. The hydraulic fluid flown into the X-axis hydraulic cylinder 75 moves the X-axis outer slider 63 to the direction shown by the arrow B (right-hand direction), thereby narrowing the oil chamber 76' of the X-axis hydraulic cylinder 76. Hydraulic fluid is then flown out from the oil chamber 76' through the hose 47 into the hydraulic cylinder 41 of the micromanipulator fine control unit 2. As described above, when the X-axis fine control handle 26 of the micromanipulator fine control unit 2 is rotated to move the inner slider 31 to the direction shown by the arrow B (right-hand direction), the X-axis outer slider 63 of the micromanipulator 3 is moved to the direction shown by the arrow B (right-hand direction). In this operation, the second hydraulic closed circuit functions as part of the micromanipulator fine control unit and the hydraulically-operated micromanipulator, while the first hydraulic closed circuit functions as restricting means. Ratio of the volume of the oil chambers 41', 42' to that of the oil chambers 75', 76' may vary to be of 1:5 for example so as to ensure more precise operation of the micromanipulator. As shown in Fig.2, the Y-axis fine control mechanism 51 for fore-and-aft movement of the micromanipulator 3 and the Z-axis fine control mechanism 52 for up-and-down movement have substantially the same construction as the X-axis fine control mechanism 50. When the Y-axis fine control handle 54 of the micromanipulator fine control unit 2 is rotated, the micromanipulator 3 is moved to the Y-axis directions (fore-and-aft directions). Also, when the Z-axis fine control handle 55 of the micromanipulator fine control unit 2 is rotated, the micromanipulator 3 is moved to the Z-axis directions (up-and-down directions). A mounting table 84 is attached to the X-axis outer slider 63. The mounting table 84 is provided with a non-shown V-shaped groove for inserting the base portion of the tightening device 7. The tightening device 7 is fixed to the mounting table 84 by a L-shaped fixing plate 85 and a fixing bolt 86. The tightening device 7, the holder 8 and the microtool 9 are finely movable in three dimensions by the X-axis fine displacement mechanism 80, the Y-axis fine control mechanism 81 and the Z-axis fine control mechanism 82. Referring to Fig.8, the result of a comparative test is shown. In this test, a conventional hydraulically-operated micromanipulator apparatus and the inventive-hydraulically-operated micromanipulator apparatus are kept at a room temperature, the average temperature of 23°C and the maximum temperature range of 8°C around the average temperature. The table shows the relation between temperature change and amount of drift for each hydraulically-operated micromanipulator apparatus. In both conventional and inventive micromanipulator apparatus, the volume of the hydraulic cylinder (oil chamber) provided at the micromanipulator fine control unit to that of the hydraulic cylinder (oil chamber) provided at the hydraulically-operated micromanipulator is 1:5. As a result, the inventive hydraulically-operated micromanipulator apparatus is not subject to drift. The micromanipulator apparatus according to the present invention therefore ensures precise and long-period operation. It should be understood that the present invention is not limited by the above-described embodiment. Various modifications are possible within the scope of the claimed invention. For example, relative position between the hydraulic cylinders 41, 42 of the inner slider 31 and the pistons 37, 38 of the outer slider 30 may vary such that the hydraulic cylinders 41, 42 are mounted on the outer slider 30 of the micromanipulator fine control unit 2 and a common piston is mounted on the inner slider 31. Also, relative position between the X-axis hydraulic cylinders 75, 76 of the X-axis outer slider 63 and the pistons 71, 72 of the X-axis inner slider 65 may vary so that the X-axis hydraulic cylinders 75, 76 are mounted on the X-axis inner slider 65 of the micromanipulator 3 and a common piston is mounted on the X-axis outer slider 63. Referring now to Fig.9, a modified embodiment of the hydraulically-operated micromanipulator apparatus is shown, in which the X-axis fine control mechanism 50' of the micromanipulator fine control unit includes an outer slider 87 as a basement. The outer slider 87 has a pair of guiding grooves 87a for receiving an inner slider 88 as a sliding table through a non-shown linear-way bearing. The outer slider 87 also has an oblong cutout 87b at the bottom portion thereof. The inner slider 88 is provided at the tailing end with a threaded opening 88a for the engagement with the fine control male thread 25a of the X-axis fine control screw shaft 25. At the bottom surface of the inner slider 88, a piston fixing plate 89 extends downwardly through the oblong cutout 87h of the outer slider 87. The piston fixing plate 89 is provided with a second piston 38' horizontally extending toward the side plate 13. A first hydraulic cylinder 41 is mounted on the top surface of the inner slider 88 by a cylinder fixing element 44 with its opening facing to the side plate member 33. The first piston 37 of the side plate member 33 is fitted within the first hydraulic cylinder 41 so as to be movable to the fore-and-aft directions. At the bottom surface of the outer slider 87, a second hydraulic cylinder 42 is mounted by a cylinder fixing element 45 with its opening facing to the side plate member 33. The second piston 38' of the inner slider 88 is fitted within the second hydraulic cylinder 42 so as to be movable to the fore-and-aft directions. The hydraulically-operated micromanipulator apparatus also includes the Y-axis fine control mechanism (not shown) and the Z-axis fine control mechanism (not shown), which have substantially the same construction as the X-axis fine control mechanism 50'.

Claims: A hydraulically-operated micromanipulator apparatus (1), which comprises a first operating-side piston (37) and a first operating-side hydraulic cylinder (41) operatively related to each other and finely movable relative to one another in response to movement of a fine control device (50, 50'), one of the first operating-side hydraulic cylinder and the first operating-side piston being stationarily retained, a first actuating-side piston (72) and a first actuating-side hydraulic cylinder (76) operatively related to each other and finely movable relative to one another, the first actuating-side hydraulic cylinder (76) being connected to the first operating-side hydraulic cylinder (41) through a hose (47) so as to form a first closed hydraulic circuit, one of the first actuating-side piston (72) and the first actuating-side hydraulic cylinder (76) being stationarily retained, the non-retained actuating-side piston or cylinder being attached to a fine displacement member (63), the first closed hydraulic circuit being filled with hydraulic fluid, and a compensating means for preventing expansion and contraction of hydraulic fluid within the first closed hydraulic circuit when the ambient temperature changes, characterised in that said compensating means forms another second closed hydraulic circuit similar to the first closed hydraulic circuit and includes a second operating-side piston (38,38') and a second operating-side hydraulic cylinder (42), one of the second operating-side piston (38,38') and the second operating-side hydraulic cylinder (42) being stationarily retained, the first non-retained operating side piston or cylinder being in opposing relation to the second non-retained operating side piston or cylinder, a second actuating-side piston (71) and a second actuating-side hydraulic cylinder (75), one of the second actuating-side piston (71) and the second actuating-side hydraulic cylinder (75) being stationarily retained, the second non-retained actuating-side piston or cylinder being attached to the fine displacement member (63), and the first non-retained actuating-side piston or cylinder being in opposing relation to the second non-retained actuating side piston or cylinder, a hose (48) connecting the second actuating-side hydraulic cylinder (75) and the second operating-side hydraulic cylinder (42), the second closed hydraulic circuit being filled with hydraulic fluid, and further characterised in that said second closed hydraulic circuit cooperates with said first closed hydraulic circuit, the arrangement being such that, in operation, each non-retained operating-side piston or cylinder is displaced by said fine control device (50,50') for changing the volume of hydraulic fluid within the respective operating-side hydraulic cylinder (41,42), and each non-retained actuating-side piston or cylinder is displaced with respect to its operatively related stationarily retained actuating-side hydraulic cylinder or piston when the volume changes of said operating-side hydraulic cylinders(41,42) are transmitted through the hoses (47,48) to said actuating-side hydraulic cylinders (76,75). A hydraulically-operated micromanipulator apparatus according to claim 1, wherein the volume of hydraulic fluid between said first operating-side hydraulic cylinder (41) and said first actuating-side hydraulic cylinder (76) is substantially the same as that of hydraulic fluid between said second operating-side hydraulic cylinder (42) and said second actuating-side hydraulic cylinder (75). A hydraulically-operated micromanipulator apparatus according to claim 1 or claim 2, wherein said first operating-side piston (37) and said second operating-side hydraulic cylinder (42) are stationarily retained, while said first operating-side hydraulic cylinder (41) and said second operating-side piston (38,38') are movable, and wherein the non-retained operating-side hydraulic cylinder and the non-retained operating-side piston are finely operable by said fine control device (50,50'). A hydraulically-operated micromanipulator apparatus according to any one of claims 1 to 3, wherein said first actuating-side piston (72) and said second actuating-side hydraulic cylinder (75) are stationarily retained, while said first actuating-side hydraulic cylinder (76) and said second actuating-side piston (71) are movable, and wherein the non-retained actuating-side hydraulic cylinder and the non-retained actuating-side piston are attached to said fine displacement member (63). A hydraulically-operated micromanipulator apparatus according to any one of claims 1 to 4, wherein the volume of hydraulic fluid within said first operating-side hydraulic cylinder (41) is reduced when the volume of hydraulic fluid within said second operating-side hydraulic cylinder (42) is increased, and the volume of the hydraulic fluid within said first operating-side hydraulic cylinder (41) is increased when the volume of the hydraulic fluid within said second operating-side hydraulic cylinder (42) is reduced. A hydraulically-operated micromanipulator apparatus according to any one of claims 1 to 5, wherein the micromanipulator apparatus enables three-directional fine displacement.

Inventors: YONEYAMA SHINJI, YONEYAMA, SHINJI
Applicants: NARISHIGE CO LTD, NARISHIGE CO., LTD.
Application year: 1998
Main classification: B25J7
IPC codes: C12M3, B25J7, G02B21