JP2019188298A - Agitation device and heat treatment device having the same - Google Patents

Abstract

To provide an agitation device capable of restraining a height, and a heat treatment device having the same.SOLUTION: An agitation device 32 comprises a rotary shaft 42 having the axis in the vertical direction, an agitation member 43 provided on one side in the axial direction of the rotary shaft 42, a reduction gear 45 connected to the other side in the axial direction of the rotary shaft 42 and a driving motor 46 connected to the reduction gear 45. The driving motor 46 comprises a motor output shaft 46a for outputting rotational power, and the motor output shaft 46a is arranged in an attitude in the horizontal lateral direction, and the reduction gear 45 has the axis in the vertical direction, and is integrally rotatably connected to the rotary shaft 42, and comprises a deceleration output shaft 61 for transmitting the rotational power of the motor output shaft 46a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a stirring device and a heat treatment device provided with the stirring device.

  As a heat treatment apparatus used for quenching a workpiece such as a metal part, for example, as described in Patent Document 1 below, an oil tank for storing cooling oil, and a basket in which the work is accommodated are positioned in the oil tank and above the oil tank. And an elevating device that elevates and lowers between them and a circulating device that circulates cooling oil in an oil tank are known. The circulating device circulates the cooling oil in the oil tank to positively bring the cooling oil into contact with the surface of the workpiece, thereby rapidly cooling the workpiece.

  As shown in FIG. 8, the circulation device described in Patent Document 1 is arranged from the lower side to both sides of the basket 115 in the oil tank 111, and a duct 131 that forms a cooling oil circulation path, and both sides of the basket in the oil tank 111. And a stirring device 132 that is disposed inside the duct 131 and that generates a circulating flow by stirring the cooling oil. The stirring device 132 includes a rotating shaft 142 having a vertical axis, a blade 143 provided on the lower side of the rotating shaft 142, and a drive motor 146 connected to the upper end of the rotating shaft 142.

JP 2012-126961 A

  In FIG. 8, the drive motor 146 in the stirrer 132 is arranged in an upright posture so that the axis of the output shaft is along the vertical direction, and the output shaft and the rotary shaft 142 of the stirrer 132 are concentrically connected. Is done. In this case, a coupling is required between the output shaft of the drive motor 146 and the rotary shaft 142 to connect them. In addition, the top plate 111f of the oil tank 111 requires a mount 150 in order to support the drive motor 146 and to secure the coupling space. Due to these factors, the drive motor 146 protrudes greatly from the oil tank 111 upward.

  If the drive motor 146 protrudes greatly upward in this way, when the stirring device 132 is removed from the oil tank 111 for maintenance or replacement, the stirring device 132 needs to be lifted higher, and the work becomes large. Further, since the workpiece elevating device 112 is disposed adjacent to the stirring device 132, the side space of the elevating device 112 is eroded by the drive motor 146. For this reason, there is a possibility that the drive motor 146 may interfere with maintenance of the lifting device 112 or the like, and there may be a restriction on the arrangement of components constituting the lifting device 112.

  An object of this invention is to provide the stirring apparatus which can suppress height low, and the heat processing apparatus provided with the same.

(1) The stirring device of the present invention comprises:
A rotary shaft having a vertical axis, a stirring member provided on one side of the rotary shaft, a speed reducer connected to the other side of the rotary shaft, and the speed reducer And a drive motor connected to the
The drive motor has a motor output shaft that outputs rotational power, and is arranged in a horizontal posture with the motor output shaft horizontal.
The speed reducer includes a speed reduction output shaft that has a vertical axis and is connected to the rotation shaft so as to be integrally rotatable and to which the rotational power of the motor output shaft is transmitted.

  According to the agitation device of the present invention, the drive motor is disposed in a lateral orientation in which the axis of the motor output shaft is horizontal, so that the overall height of the agitation device can be kept low.

(2) Preferably, the said deceleration output shaft is a hollow shaft formed in the cylinder shape, and the edge part of the other side of the axial direction of the said rotating shaft is inserted in the inside of the said deceleration output shaft.
With such a configuration, the deceleration output shaft and the rotation shaft can be arranged overlapping in the height direction, and the height of the stirring device can be further reduced.

(3) Preferably, the bearing further includes a bearing device that rotatably supports the rotating shaft and receives a radial load from the rotating shaft and a thrust load from the rotating shaft, the speed reducer, and the drive motor. Yes.
According to this configuration, since the thrust load from the speed reducer and the drive motor can be received by the bearing device, a frame for supporting them becomes unnecessary, and the height of the stirring device can be further reduced.

(4) Preferably, a rotation preventing mechanism that restricts rotation around the rotation shaft of the reduction gear and the drive motor is provided, and the rotation prevention mechanism is an axis of the rotation shaft with respect to the reduction gear. It has a structure that absorbs surrounding loads.
With such a configuration, it is possible to reduce a load applied to the speed reducer when the rotational power of the drive motor is transmitted to the output shaft of the speed reducer, and to suppress damage to the speed reducer.

(5) The heat treatment apparatus of the present invention
A heat treatment chamber for heat treating the workpiece;
The stirring device according to any one of (1) to (4), wherein the fluid in the heat treatment chamber is stirred.
With such a configuration, it is possible to provide a heat treatment apparatus in which the height of the stirring apparatus is kept low.

(6) Preferably, it further includes a lifting device that lifts and lowers the workpiece up and down between the inside of the heat treatment chamber and a position above it,
The speed reducer and the drive motor of the stirring device are disposed adjacent to the side of the lifting device above the heat treatment chamber.
With such a configuration, the side space of the lifting device is less likely to be eroded by the drive motor, and the space is used effectively, for example, for maintenance of the lifting device or for the placement of parts. You can do it.

(7) The drive motor in the stirring device is disposed on the opposite side of the lifting device with the reduction gear interposed therebetween.
With such a configuration, an operation for the drive motor, for example, a wiring operation for the drive motor can be easily performed.

  According to the present invention, the height of the stirring device can be kept low.

It is front explanatory drawing which shows the heat processing apparatus which concerns on one Embodiment. It is plane explanatory drawing of a heat processing apparatus. It is sectional explanatory drawing which looked at the stirring apparatus from the front. It is the A section enlarged view of FIG. It is a section explanatory view showing roughly the internal structure of a reduction gear and a drive motor. FIG. 4 is a view taken in the direction of arrow B in FIG. 3. It is the C section enlarged view of FIG. It is front explanatory drawing which shows the heat processing apparatus which concerns on a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory front view showing a heat treatment apparatus according to an embodiment. FIG. 2 is an explanatory plan view of the heat treatment apparatus.
In the following description, the left-right direction in FIG. 1 is the left-right direction of the heat treatment apparatus, and the paper penetration direction in FIG. 1 is the front-rear direction of the heat treatment apparatus.

  The heat treatment apparatus 10 according to the present embodiment is a quenching apparatus that immerses a workpiece such as a metal part heated to a predetermined temperature in a cooling oil (cooling liquid) E and rapidly cools the workpiece. The heat treatment apparatus 10 includes an oil tank (liquid tank) 11, an elevating device 12, and a circulation device 13.

(Composition of oil tank)
The oil tank 11 constitutes a heat treatment chamber and is formed in a substantially rectangular parallelepiped box shape. The oil tank 11 has a rectangular bottom portion 11a in plan view, and side wall portions 11b, 11c, 11d, and 11e that rise upward from four sides of the bottom portion 11a. The bottom part 11a is formed in the rectangular shape long in the left-right direction. Accordingly, the oil tank 11 is formed such that the width in the left-right direction is larger than the depth in the front-rear direction. Top plates 11 f are provided on both the left and right sides of the oil tank 11, and the central part in the left-right direction of the oil tank 11 is open upward.

  Cooling oil E for cooling the workpiece is stored in the oil tank 11. Further, in the oil tank 11, a workpiece loading region R for loading a workpiece is set at a substantially central portion in the left-right direction and the front-rear direction. In this work input area R, the basket 15 containing the work is input.

(Configuration of lifting device)
As shown in FIG. 1, the basket 15 containing the workpiece is moved up and down in the vertical direction between the inside of the oil tank 11 and the upper position of the oil tank 11 by the lifting device 12. The lowered basket 15 is positioned in the workpiece input region R described above. The basket 15 is composed of a net-like tray that is rectangular in plan view, and has a structure that allows the cooling oil E to flow inside and outside. A large number of workpieces heated to the quenching temperature are accommodated in the basket 15. The basket 15 is supported by the elevating frame 21 in a state where a plurality of baskets are stacked in the vertical direction. In the illustrated example, five baskets 15 are stacked in the vertical direction.

As shown in FIG. 1, the lifting device 12 includes a lifting frame 21 that supports the basket 15, a driving device 22 that drives the lifting frame 21 to move up and down, and a guide member 23 that guides the lifting and lowering of the lifting frame 21. I have.
The drive device 22 is attached to the device frame 14 provided on the upper part of the oil tank 11 and moves up and down in a state where the lifting frame 21 is suspended. The drive device 22 according to the present embodiment includes a lift chain 22a that suspends the lift frame 21, a drive shaft 22c that includes a sprocket 22b around which the lift chain 22a is wound, a drive motor 22d that rotationally drives the drive shaft 22c, and the like. Yes.

(Configuration of circulation device)
As shown in FIG. 1, the circulation device 13 includes a duct 31 and a stirring device 32. The duct 31 includes a vertical pipe portion 31A and a curved pipe portion 31B. The vertical pipe portion 31A is disposed on both the left and right outer sides of the workpiece input region R. The curved pipe portion 31B is bent into a substantially L shape when viewed from the front, one end is connected to the lower end portion of the vertical pipe portion 31A, and the other end faces the work input region R below.

  As shown in FIG. 2, two stirring devices 32 are provided on each of the left and right sides of the oil tank 11. As shown in FIG. 1, each stirring device 32 includes a screw 41, a support device 44, a speed reducer 45, and a drive motor 46. The screw 41 includes a rotating shaft 42 having a vertical axis L1 and a blade (stirring member) 43 attached to the rotating shaft 42. The lower side of the rotating shaft 42 and the blade 43 are disposed in the vertical pipe portion 31 </ b> A of the duct 31 in the oil tank 11.

  The support device 44 is attached to the top plate 11f of the oil tank 11, and supports the rotary shaft 42 in a freely rotatable manner. The rotating shaft 42 extends upward from the top plate 11 f of the oil tank 11, and its upper end is connected to the speed reducer 45. A drive motor 46 is connected to the speed reducer 45. The reduction gear 45 and the drive motor 46 are disposed adjacent to the side of the lifting device 12.

  The screw 41 is rotationally driven around the axis L <b> 1 of the rotary shaft 42 when the rotational power of the drive motor 46 is transmitted via the speed reducer 45. And the screw 41 produces | generates the flow which goes to upper direction from the downward direction to the cooling oil E in 31 A of vertical pipe parts of the duct 31. As shown in FIG. Due to the flow of the cooling oil E, the cooling oil E below the work input region R is sucked from the suction port 31B1 of the curved pipe part 31B and flows out from the upper end of the vertical pipe part 31A. The cooling oil E that has flowed out from the upper end of the vertical pipe portion 31A flows from the upper side to the lower side of the workpiece input region R and is sucked again from the suction port 31B1 of the curved pipe portion 31B. By such an action, the cooling oil E circulates in the oil tank 11, and the work arranged in the work input region R is appropriately cooled.

(Specific configuration of the stirring device)
FIG. 3 is a front view of the stirring device 32.
A circular opening 11 f 1 is formed in the top plate 11 f of the oil tank 11, and the opening 11 f 1 is closed by a base plate 47. The base plate 47 is detachably attached to the top plate 11f of the oil tank 11 by a fastener 48 made of bolts and nuts. An opening 47a is formed at the center of the base plate 47, and a support device 44 is disposed in the opening 47a.

  The support device 44 includes a support cylinder 51 formed in a cylindrical shape, and a mounting plate 52 fixed to the upper end of the support cylinder 51. The mounting plate 52 is detachably attached to the base plate 47 with a fastener 53 made of bolts and nuts while being mounted on the base plate 47. In the center of the mounting plate 52, the rotating shaft 42 of the screw 41 penetrates in the vertical direction. A bearing unit (bearing device) 54 is mounted on the mounting plate 52. A bearing unit 55 is also attached to the lower end of the support cylinder 51.

  FIG. 4 is an enlarged view of a portion A in FIG. The upper bearing unit 54 includes a bearing case 56 and a rolling bearing 57 provided in the bearing case 56. A flange portion 56 a is provided on the outer peripheral portion of the bearing case 56, and the flange portion 56 a is detachably attached by a fastener 58 such as a bolt while being placed on the attachment plate 52.

  The rolling bearing 57 includes an inner ring 57a, an outer ring 57b, and a plurality of rolling elements 57c disposed between the inner ring 57a and the outer ring 57b. The rolling bearing 57 of this embodiment is a ball bearing. The outer ring 57 b is attached to the bearing case 56, and the inner ring 57 a is fixed to the outer peripheral surface of the rotating shaft 42 of the screw 41. The outer peripheral surface of the outer ring 57b and the inner peripheral surface of the bearing case 56 are formed in a spherical shape. Therefore, the outer ring 57 b is attached to the bearing case 56 so as to be swingable. The rolling bearing 57 is aligned with the outer ring 57 b swinging with respect to the bearing case 56.

The lower bearing unit 55 also has substantially the same configuration as the upper bearing unit 54. The upper and lower bearing units 54 and 55 rotatably support the rotating shaft 42 by the rolling bearing 57 and receive a radial load from the rotating shaft 42 to suppress the swing of the rotating shaft 42.
The upper bearing unit 54 also receives a thrust load from the rotary shaft 42 by the rolling bearing 57. Further, the rolling bearing 57 receives a thrust load from the speed reducer 45 and the drive motor 46 and supports them as will be described later.

FIG. 5 is an explanatory cross-sectional view schematically showing the internal structure of the speed reducer 45 and the drive motor 46.
The drive motor 46 includes a casing 46b, and a motor output shaft 46a, a rotor 46c, and a stator 46d disposed in the casing 46b. The motor output shaft 46a is provided so as to be rotatable integrally with the rotor 46c, protrudes from the casing 46b, and is inserted into the speed reducer 45. The drive motor 46 is arranged in a lateral orientation with the axis L2 of the motor output shaft 46a being horizontal.

  The speed reducer 45 includes a casing 45a and a speed reducing output shaft 61 and a speed reducing mechanism 62 disposed in the casing 45a. A casing 46b of the drive motor 46 is connected to the side surface of the casing 45a. The deceleration output shaft 61 has a vertical axis. The deceleration output shaft 61 is a hollow shaft formed in a cylindrical shape.

  The reduction mechanism 62 includes a pinion gear 62a provided on the motor output shaft 46a, a bevel gear 62b such as a hypoid gear that meshes with the pinion gear 62a, a small gear 62c that is arranged concentrically with the bevel gear 62b, and a reduction output shaft 61 that meshes with the small gear 62c. It has a large gear 62d that rotates integrally. The rotation of the motor output shaft 46a is decelerated in a state where the direction is changed by 90 ° by the pinion gear 62a and the bevel gear 62b, and is further transmitted to the deceleration output shaft 61 in a state of being further decelerated by the small gear 62c and the large gear 62d. The speed reduction mechanism 62 is not limited to the structure illustrated in FIG. 5, and any conventionally known structure can be applied. For example, a structure in which the small gear 62c and the large gear 62d are omitted and the bevel gear 62b is provided on the reduction output shaft 61 may be employed. Further, the motor output shaft 46a and the deceleration output shaft 61 of the speed reducer 45 may be orthogonal to each other or twisted.

  6 is a view taken in the direction of arrow B in FIG. As shown in FIGS. 3 and 6, the deceleration output shaft 61 of the speed reducer 45 is disposed concentrically with the axis L <b> 1 of the rotating shaft 42 and is connected to the upper end portion of the rotating shaft 42. Specifically, the upper end portion of the rotating shaft 42 is inserted into a cylindrical deceleration output shaft 61. The rotating shaft 42 and the deceleration output shaft 61 are coupled so as to be integrally rotatable by key coupling.

  As shown in FIGS. 4 and 5, the rotating shaft 42 has a large-diameter portion 42 a whose outer diameter is enlarged above the upper bearing unit 54. The lower end surface of the deceleration output shaft 61 is in contact with the upper end surface of the large diameter portion 42a. Therefore, the load of the speed reducer 45 is applied from the speed reduction output shaft 61 to the rotary shaft 42 via the large diameter portion 42a. The speed reducer 45 is supported by the bearing unit 54 via the rotating shaft 42. Further, since the drive motor 46 is connected to the speed reducer 45, the drive motor 46 is supported by the bearing unit 54 like the speed reducer 45.

  As shown in FIG. 3, the stirring device 32 includes a detent mechanism 40. The anti-rotation mechanism 40 includes an anti-rotation member 33 and fixing means for fixing the anti-rotation member 33 to the speed reducer 45 and the base plate 47. The rotation preventing member 33 has an upper plate 33a connected to the lower surface of the speed reducer 45, a lower plate 33b connected to the base plate 47, and a vertical plate 33c connecting the upper plate 33a and the lower plate 33b. ing. The upper plate 33a is connected to the speed reducer 45 by a bolt 34 as a fixing means.

FIG. 7 is an enlarged view of a portion C in FIG.
As shown in FIG. 7, a mounting hole 33b1 is formed in the lower plate 33b of the anti-rotation member 33, and a cylindrical spacer 35 and a bolt 36 are inserted into the mounting hole 33b1. The bolt 36 is inserted from below into a bolt insertion hole 47 b formed in the base plate 47 and the spacer 35, and a nut 39 is fastened to the upper end portion via a washer 37 and a spring washer 38. The spacer 35 is pressed against the washer 37 and the base plate 47 by fastening the nut 39. Therefore, the spacer 35, the bolt 36, the washer 37, the spring washer 38, and the nut 39 constitute fixing means for fixing the rotation preventing member 33 to the base plate 47.

  Clearances t1, t2, and t3 are formed between the outer peripheral surface of the spacer 35 and the mounting hole 33b1, between the washer 37 and the lower plate 33b, and between the lower plate 33b and the base plate 47, respectively. The gap t1 is, for example, 1 mm or more. The gap t1 is provided to absorb the deviation between the mounting hole 33b1 and the bolt insertion hole 47b due to processing accuracy. Further, the gap t1 has a dimension that allows the lower plate 33b to shake due to the drive of the drive motor 46, as will be described below. The gaps t2 and t3 are formed by making the height of the spacer 35 larger than the thickness of the lower plate 33b.

  The anti-rotation mechanism 40 restricts the reduction gear 45 and the drive motor 46 from rotating about the axis L <b> 1 of the rotary shaft 42 as a reaction of the rotation of the deceleration output shaft 61 accompanying the drive of the drive motor 46. The anti-rotation mechanism 40 is fastened by a bolt 36 and a nut 39 in a state where the lower plate 33b of the anti-rotation member 33 is spaced from the spacer 35, the washer 37, and the base plate 47 by gaps t1, t2, and t3. Thus, a minute movement (for example, movement of 1 mm or more) around the rotation shaft 42 of the reduction gear 45 and the drive motor 46 is allowed. Therefore, when the drive motor 46 is driven, the loads on the reduction gear 45 are absorbed by the gaps t1 to t3 (particularly, the gap t1), and damage to the reduction gear 45 is prevented.

  As described above, the drive motor 46 is disposed in a lateral orientation in which the axis L2 of the motor output shaft 46a is horizontal. Therefore, compared with the case where the drive motor 146 is arranged in a standing posture as in the conventional technique shown in FIG. When the height of the stirring device 32 is kept low, when the stirring device 32 is removed from the oil tank 11 for maintenance, replacement, etc., the height at which the stirring device 32 is lifted can be suppressed, and the work can be easily performed.

  Further, when the drive motor 46 is arranged in a lateral orientation, a wide space on the side of the lifting device 12 is secured as shown in FIG. Therefore, the freedom degree of arrangement | positioning of the components which comprise the raising / lowering apparatus 12, for example, drive motor 22d, etc. can be raised. Moreover, maintenance etc. can be easily performed using the side space.

  Since the drive motor 46 is connected to the side surface of the speed reducer 45, the load of the drive motor 46 is also applied to the rotating shaft 42 together with the speed reducer 45 and is further supported by the bearing unit 54. Therefore, a stand for supporting the speed reducer 45 and the drive motor 46 is not required, and the height of the agitating device 32 can be kept low correspondingly.

  Furthermore, since the deceleration output shaft 61 of the speed reducer 45 is a hollow shaft, and the upper end portion of the rotating shaft 42 is inserted into the deceleration output shaft 61, both shafts 61 and 42 overlap in the height direction. Also by this, the reduction gear 45 and the drive motor 46 can be arrange | positioned in a lower position, and the height of the stirring apparatus 32 can be restrained low.

  As shown in FIG. 1, in this embodiment, the drive motor 46 is arrange | positioned on the opposite side to the raising / lowering apparatus 12 on both sides of the reduction gear 45. As shown in FIG. Therefore, the drive motor 46 is arranged toward the outer side of the oil tank 11 in the left-right direction, so that work on the drive motor 46, for example, wiring work on the terminal box 46e can be easily performed. Moreover, the freedom degree of arrangement | positioning of the stirring apparatus 32 can be raised, such as arrange | positioning the stirring apparatus 32 close to the raising / lowering apparatus 12. FIG.

  As shown in FIG. 2, in this embodiment, two stirring devices 32 are arranged side by side before and after the oil tank 11, and the drive motors 46 are arranged such that the axis L2 of the motor output shaft 46a is parallel to each other. Is arranged. Accordingly, the degree of freedom of arrangement of the agitating devices 32 can be increased, for example, by arranging the two agitating devices 32 as close as possible without causing the drive motors 46 to interfere with each other. Wiring work and the like for the motor 46 can be performed from the same side.

The heat treatment apparatus of the present invention is not limited to the above embodiment, and can be appropriately changed within the scope of the invention described in the claims.
For example, the heat treatment apparatus includes two stirring devices on the left and right sides of the oil tank, but may include one or three or more stirring devices. Moreover, you may provide the stirring apparatus before and behind the oil tank. The blade of the stirrer may generate a fluid flow from above to below.
The heat treatment apparatus is not limited to heat treatment of the workpiece with cooling oil (cooling liquid), and may be heat treatment with gas (atmosphere gas). In this case, the stirring device can be used to stir the atmospheric gas.
In the above embodiment, the bearing device that supports the screw, the speed reducer, and the drive motor of the stirring device is illustrated as having a ball bearing. However, the bearing device is not limited to this and receives a radial load and a thrust load. Other types of rolling bearings that can be used are also possible.

10: Heat treatment apparatus 11: Oil tank (heat treatment chamber)
12: Lifting device 32: Stirrer 33: Non-rotating member 41: Screw 42: Rotating shaft 43: Blade (stirring member)
45: Reducer 46: Drive motor 46a: Motor output shaft 54: Bearing unit (bearing device)
61: Deceleration output shaft

Claims (7)

A rotary shaft having a vertical axis, a stirring member provided on one side of the rotary shaft, a speed reducer connected to the other side of the rotary shaft, and the speed reducer And a drive motor connected to the
The drive motor has a motor output shaft that outputs rotational power, and is arranged in a horizontal posture with the motor output shaft horizontal,
The speed reducer includes a speed reducing output shaft that has a vertical axis and is connected to the rotating shaft so as to be integrally rotatable and to which rotational power of the motor output shaft is transmitted.   The stirring device according to claim 1, wherein the deceleration output shaft is a hollow shaft formed in a cylindrical shape, and the other end portion in the axial direction of the rotating shaft is inserted into the deceleration output shaft.   The bearing device further includes a bearing device that rotatably supports the rotating shaft and that receives a radial load from the rotating shaft and a thrust load from the rotating shaft, the speed reducer, and the drive motor. 2. The stirring device according to 2.   The anti-rotation mechanism further restricts the rotation of the speed reducer and the drive motor about the axis of the rotary shaft, and the anti-rotation mechanism absorbs the load around the axis of the rotary shaft with respect to the speed reducer. The stirrer according to any one of claims 1 to 3, wherein the stirring device has a structure. A heat treatment chamber for heat treating the workpiece;
The heat processing apparatus provided with the stirring apparatus of any one of Claims 1-4 which stir the fluid in a heat processing chamber. A lifting device that moves the workpiece up and down between the inside of the heat treatment chamber and its upper position,
The heat treatment apparatus according to claim 5, wherein the speed reducer and the drive motor of the stirring device are disposed adjacent to a side of the lifting device above the heat treatment chamber. The heat processing apparatus of Claim 6 with which the said drive motor in the said stirring apparatus is arrange | positioned on the opposite side to the said raising / lowering apparatus on both sides of the said reduction gear.

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