JP6786771B2 - Rotary blades for mowers and mowers using them - Google Patents

Description

The present invention relates to a rotary blade for a mower and a mower using the rotary blade.

There is a portable power mower as a device for removing weeds that grow on the banks of fields. This mowing machine is also called a brush cutter, and is configured to transmit the rotational power generated by a small engine to the rotary blade supported at the tip of the operation tube, and the operator uses a throttle lever to transmit the engine. Alternatively, while controlling the rotation of the rotary blade rotated by this, the operation tube is swung left and right to perform the desired mowing work.

Among the rotary blades suitable for this type of portable power mower, there are those shown in Patent Documents 1 and 2 as nylon cord type rotary blades, for example.

In the rotary blade shown in Patent Document 1, a plurality of circular winding blocks are erected on the upper surface of the peripheral portion of the mounting disk, and the distance between adjacent winding blocks is set so that the nylon cord can pass through. is there. In such a configuration, the nylon cord has a predetermined length, and a large diameter portion is provided on the base end side by tying a knot at one end, and this is provided between the free end on the tip side and the adjacent winding block. It can be easily mounted by passing it from the inside of the mounting disk. In this state, the nylon cord is maintained in a state in which the large diameter portion on the base end side is locked between the adjacent winding blocks and the free end on the tip end side extends from the outer circumference of the mounting disk.

Further, Patent Document 2 is equipped with a holding member that rotates together with a rotary blade mounting shaft and winds and holds a nylon cord, and a guide member that is rotatably supported around the rotation shaft with respect to the holding member. A nylon cord type rotary blade is shown.

The rotary blade shown in Patent Document 2 has an adjustment function capable of extending the extension length by feeding out the nylon cord wound around the holding member when the extension length is shortened due to wear of the nylon cord. In addition to being provided, the guide member blocks the entry of weeds and other cutting objects inward from the outer circumference of the guide member, so the cutting object is efficiently cut by the tip of the nylon cord that turns at high speed. Has a function.

However, since each of the rotary blades shown in Patent Documents 1 and 2 is configured so that one nylon cord extends from various places in the circumferential direction, the cutting ability of the tip portion of the nylon cord is not sufficient. Naturally, there is a limit, and there is a problem that weeds having thicker stems than a predetermined value and weeds that have become dry and hard cannot be easily cut.

Japanese Unexamined Patent Publication No. 7-177812 International Publication WO2007 / 023758

The present invention has been devised based on the above circumstances, and provides a rotary blade for a mower with higher cutting efficiency while using a nylon cord used for a conventional nylon cord type rotary blade. That is the main issue.

In order to solve the above problems, the following technical means are adopted in the present invention.

The rotary blade for a mowing machine provided by the first side surface of the present invention has a holding member that is attached to a rotary blade mounting shaft of the mowing machine and is rotated, and a holding member whose base end side is held by the holding member and whose tip side is the holding member. A rotary blade for a mowing machine provided with a cord-shaped cutting member extending outward in the radial direction, which is lower than the cord-shaped cutting member and has a radius lower than the outer circumference of the holding member integrally with the holding member. A flange portion that extends outward in the direction and prevents the object to be cut from entering inward in the radial direction is provided, and the holding member and the holding member and the holding member below the flange portion are centered on the rotation axis of the holding member. It is rotatable relative to the flange portion, has an outer diameter smaller than the outer diameter of the flange portion, and has an outer diameter larger than 1/2 of the outer diameter of the flange portion, and the bottom surface is substantially flat. It is characterized by including a ground contact member.

The mowing machine provided by the second aspect of the present invention includes a power source and a rotary blade mounting shaft that is rotationally driven by the power of the power source, and the rotary blade mounting shaft includes the first side surface. It is characterized in that a rotary blade for a mowing machine according to the above is attached.

It is a perspective view of the rotary blade for a mower which concerns on the reference example of this invention. It is a top view of the rotary blade for a mower shown in FIG. It is a figure corresponding to the cross section of line III-III of FIG. 2, and also shows the attachment structure to the mower. FIG. 2 is a sectional view taken along line IV-IV of FIG. FIG. 2 is a sectional view taken along line VV of FIG. It is a bottom view of the grounding member of the rotary blade for a mower shown in FIG. It is explanatory drawing of an example of the attachment method of the cord-shaped cutting member (nylon cord). It is a perspective view of the rotary blade for a mower which concerns on one Embodiment of this invention. It is a top view of the rotary blade for a mower shown in FIG. It is a figure corresponding to the X-X line cross section of FIG. 9, and also shows the attachment structure to a mower. 9 is a sectional view taken along line XI-XI of FIG. It is an operation explanatory view of the rotary blade for a mower shown in FIG. It is explanatory drawing of another example of the attachment method of the cord-shaped cutting member (nylon cord).

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 to 7 show a form of a rotary blade A for a mower according to a reference example of the present invention and a mower B in which the rotary blade A is used. As is well shown in FIGS. 1 and 3, in the mower B, a small engine (not shown) as a drive source is connected to the base end side of the operation pipe 12, and its rotational output is operated. It is configured to be transmitted to the tip of the operation pipe 12 via the transmission shaft 13 inserted in the pipe 12. As the small engine, for example, an engine having a displacement of about 25 cc is used in consideration of the portability of the operator. A small engine may be directly attached to the base end of the operation tube 12, or an engine mounted on a backpack, for example, may be connected via a flexible transmission shaft.

As is well shown in FIG. 3, the rotary blade mounting shaft 14 is supported by the gear case 16 at the tip of the operation pipe 12, and the rotary blade mounting shaft 14 and the transmission shaft 13 are connected to a bevel gear mechanism (not shown). Is linked by. A spline is formed on the outer periphery of the rotary blade mounting shaft 14, and a screw hole 14a extending in the axial direction is formed at the shaft end. A metal rotary blade retainer 17 is spline-fitted to the rotary blade mounting shaft 14. A short-axis columnar bulging portion 17a is formed on the lower surface of the rotary blade retainer 17.

The rotary blade A characterized by the present invention is attached to the rotary blade mounting shaft 14.

As shown in FIGS. 1, 2 and 3, the rotary blade A has a holding member 100 that is attached to the rotary blade mounting shaft 14 and is rotated, and a base end side is held by the holding member 100. A plurality of cord-shaped cutting members whose tip side extends outward in the radial direction of the holding member 100, and below the holding member 100, can rotate relative to the holding member 100 about its rotation axis. It is provided with a grounding member 200 supported by the above. As the cord-shaped cutting member, as shown well in FIG. 4, a commercially available nylon cord 40 having a large diameter portion 40a at the base end and having a thickness of about 3 mm and a predetermined length can be used.

As is clearly shown in FIG. 3, the holding member 100 includes a horizontal disk-shaped mounting base 110 having a mounting hole 110a having a diameter corresponding to the outer diameter of the bulging portion 17a of the rotary blade retainer 17 and the mounting thereof. A thick annular portion 120 having an upper surface continuous with the upper surface of the mounting base 110 on the outer peripheral portion of the base 110 and formed to be thicker than the thickness of the mounting base 110, and horizontal from the lower surface of the thick annular portion 120. It has a flange portion 160 extending in a direction and having a constant outer diameter. In this reference example, the mounting base 110 and the thick annular portion 120 are integrally formed of, for example, resin, and the flange portion 160, which is separately formed of resin, is integrally formed by screws 152 (see FIG. 5). It has been transformed. The outer diameter of the flange portion 160 is, for example, 200 to 400 mm, preferably 250 to 350 mm, but is not limited thereto.

The thick annular portion 120 is a portion that holds a plurality of nylon cords 40, and has the following configurations in two regions facing each other in the radial direction.

In the thick annular portion 120, a cord insertion space 130 having a rectangular cross section extending in a range of a central angle of approximately 90 ° along the circumferential direction in which the thick annular portion 120 extends is formed, and the cord insertion space 130 is formed. One end thereof is closed, and the other end is open to the outer peripheral surface 120a of the thick annular portion 120. Four cord connecting portions 141, 142, 143, and 144 are formed at equal intervals on the ceiling wall 131 of the cord insertion space 130. As shown well in FIG. 4, each cord connecting portion 141, 142, 143, 144 is a hole 132 having a size through which the general portion of the nylon cord 40 can be inserted and the large diameter portion 40a cannot be inserted. Is formed through the ceiling wall 131. In this reference example, the seating surface 132a on which the large diameter portion 40a of the nylon cord 40 is seated is inclined so that the degree of curvature of the nylon cord 40 reaching the cord insertion space 130 through the hole 132 is reduced. In addition, the portion of the inner wall of the hole 132 where the curved portion of the nylon cord 40 contacts is smoothly rounded. Further, in the vicinity of the exit of the cord insertion space 130, a hanging portion 150 for changing the direction of the tip end side of the nylon cord 40 inserted into the cord insertion space 130 to extend outward in the radial direction of the holding member 100. Is provided. In this reference example, as shown in FIG. 3, the hanging portion 150 is a screw arranged so as to hang between a part of the ceiling wall 131 of the thick annular portion 120 and the flange portion 160. It is formed by interposing a cylindrical collar 151 having a predetermined outer diameter so as to be fitted to 152.

As shown in FIG. 3, the grounding member 200 has a short-axis dome shape that smoothly bulges downward as a whole and is accommodated in a space defined by the inner surface of the thick annular portion 120 of the holding member 100. It is presented and has a tubular portion 210 on the inner circumference. Further, as shown in FIG. 6, four concave grooves 260 extending in the radial direction and arranged in a cross shape are provided on the lower surface of the grounding member 200. The grounding member 200 is made of, for example, metal or resin. The grounding member 200 is attached to the rotary blade mounting shaft 14 or the holding member 100 by interposing a berianing 250 between the bearing receiver 220 integrated with the rotary blade mounting shaft 14 or the holding member 100 and the tubular portion 210. On the other hand, the rotary blade mounting shaft 14 is rotatably supported around the rotation center.

In this reference example, the rotary blade A having the above configuration fits the mounting hole 110a of the mounting base 110 of the holding member 100 into the bulging portion 17a of the rotary blade holder 17, and the bearing holder 230 is on the lower surface side of the mounting base 110. The bearing receiver 220 that rotatably supports the grounding member 200 as described above is stacked, and the mounting bolt 15 passed through the center hole 221 of the bearing receiver 220 and the center hole 231 of the bearing retainer 230 from below is passed through the rotary blade mounting shaft. By screwing into the screw hole 14a of 14, it is attached to the rotary blade mounting shaft 14.

In the present invention, a plurality of nylon cords 40 are extended from the same position in the circumferential direction of the holding member 100. In the following, an example of a method of attaching the nylon cords 40 when two nylon cords 40 are extended from the same position in the circumferential direction of the holding member 100 will be described.

Of the cord connecting portions 141, 142, 143, 144 provided in the thick annular portion 120 at four locations along each cord insertion space 130, the first cord connecting portion 141 and the second cord are arranged in order from the hanging portion 150. The connecting portion 142, the third cord connecting portion 143, and the fourth cord connecting portion 144. The same two nylon cords 40 are used, and as shown in FIGS. 4 and 7, the base ends are connected to the third and fourth cord connecting portions 143 and 144. Specifically, first, a nylon cord 40 is passed through each hole 132 of the third cord connecting portion 143 and the fourth cord connecting portion 144 from the tip portion thereof, the cord insertion space 130 is passed, and the hanging portion 150 is hung around. Pull out the holding member 100 outward in the radial direction. As shown in FIG. 4, these nylon cords 40 have a large diameter portion 40a on the base end side seated and locked on the inclined seat surface 132a on the outer surface of the hole 132, whereby the base end is locked. The side is substantially connected to the third cord connecting portion 143 and the fourth cord connecting portion 144. As a result, the two nylon cords 40 are hung around the same hooking portion 150, and extend in the radial direction from the same position in the circumferential direction of the holding member 100. The length of the nylon cord 40 is, for example, when the base end is connected to the fourth cord connecting portion 144, the tip of the nylon cord 40 extends in the radial direction of the holding member 100, and the tip thereof is the outer edge of the flange portion 160. It is set so as to protrude from about 30 to 60 mm.

When the mowing operation is performed for a certain period of time using the rotary blade A for a mowing machine as described later, the tip of the nylon cord 40 is worn and the length extending from the flange portion 160 is gradually shortened. In that case, the nylon cord 40 connected to the third cord connecting portion 143 is reconnected to the second cord connecting portion 142, and the nylon cord 40 connected to the fourth cord connecting portion 144 is connected to the third cord. Reconnect to unit 143. The nylon cord 40 can be easily removed by pulling the large diameter portion 40a on the base end side thereof, and the nylon cord 40 can be reconnected to the adjacent cord connecting portion in the same manner as described above. .. As a result, the extension length of the nylon cord 40 from the flange portion 160 can be extended by the length corresponding to the distance between the adjacent cord connecting portions 141, 142, 143, 144. When the tips of the two nylon cords 40 connected to the second and third cord connecting portions 142 and 143 are worn again and shortened, the first and second cord connecting portions 141 and 142 are further connected. You can reconnect them.

When mowing the grass using the mowing machine B, for example, when the throttle opening of the engine is increased by operating the throttle lever, the holding member 100 or the nylon cord of the rotary blade A is generated by the rotational output of the engine. 40 is rotated. The rotational output of the engine is decelerated from the transmission shaft 13 by a bevel gear (not shown) in the gear case 16 and transmitted to the holding member 100 or the nylon cord 40 via the rotary blade mounting shaft 14. The rotation speed of the holding member 100 to the nylon cord 40 reaches, for example, 5,000 to 6,000 rpm. Assuming that the outer diameter of the holding member 100 of the rotary blade A (outer diameter of the flange portion 160) is, for example, 300 mm, the peripheral speed of the nylon cord 40 at the outer peripheral portion of the holding member 100 reaches about 340 km / h. When the rotary blade A is moved along the ground, the object to be cut such as weeds is laterally swiveled by the nylon cord 40 that swivels at high speed while being blocked from entering further inward in the radial direction by the flange portion 160. It receives a strong impact from the direction and is cut off.

Moreover, in the rotary blade A of this reference example, the number of nylon cords 40 extending from the same portion of the holding member 100 is two or more. As described above, during the rotation of the rotary blade A, the nylon cord 40 collides with a cutting target such as weeds at high speed to cut it, but two or more nylon cords 40 collide with the cutting target at the same time. Therefore, the impact force received by the object to be cut is multiple times that when one nylon cord 40 collides, and therefore weeds with relatively thick stems and weeds that have become dry and hard can be easily treated. Can be reaped. As a result, the applicable range of mowing work that can be performed using the safe cord type rotary blade A is dramatically expanded. Moreover, the nylon cord 40, which has been used for this type of cord-type rotary blade, can be used as it is, which is convenient.

Further, in the rotary blade A of this reference example, a grounding member 200 is provided below the holding member 100 so as to be rotatably supported around the rotation axis of the holding member 100 with respect to the holding member 100 or the rotary blade mounting shaft 14. ing. Since the rotational driving force from the engine does not act on the grounding member 200, the holding member 100 or the nylon cord 40 can be rotated while the grounding member 200 is in contact with the ground. Moreover, since the ground contact member 200 in this reference example has a short-axis dome shape that smoothly bulges downward, it can easily slide and move with respect to the ground while being in contact with the ground. This means that the mowing work can be performed while the rotary blade A is moved along the ground while the weight of the tip end portion of the operation pipe 12 of the mowing machine B or the rotary blade A is supported on the ground via the grounding member 200. Means. As a result, the labor of the worker is remarkably reduced, and the height of the stump after mowing is uniform, so that the mowing work can be performed with good quality. Since the grounding member 200 is arranged so as to be accommodated in the space defined by the inner surface of the thick annular portion 120 of the holding member 100, the grass pieces cut by the nylon cord 40 are placed on the grounding member 200. It is possible to effectively avoid a situation in which the grounding member 200 invades the inside and hinders the relative rotation of the grounding member 200 with respect to the mounting shaft 14. Further, since the ground contact member 200 is provided with a concave groove 260 extending in the radial direction on the lower surface thereof, the ground contact member 200 does not inadvertently rotate in a state of being in contact with the ground, and good sliding motion with respect to the ground can be realized.

8 to 13 show a rotary blade A1 for a mower according to an embodiment of the present invention and a mower B1 to which the rotary blade A1 is used. The rotary blade A1 for a mower of this embodiment is different from the rotary blade A for a mower according to a reference example in the configuration of the grounding member 200a and the attachment structure of the nylon cord 40a, and the remaining configurations are the same. In the following, the differences from the rotary blade A for the mower according to the above reference example will be mainly described, and the same members or parts as the rotary blade A for the mower will have the same reference numerals as those attached in FIGS. 1 to 7. A detailed description will be omitted.

The grounding member 200a is a central cylinder portion 210a that is rotatably supported by a pair of upper and lower bearings 250 with respect to the bearing receiver 220, and an intermediate cylinder located inside the inner side surface of the thick annular portion 120 of the holding member 100. A donut-shaped bottom wall 212a connecting the lower ends of the central cylinder 210a and the intermediate cylinder 211a, and a flange 213a extending outward in the radial direction so as to be continuous with the bottom wall 212a. To be equipped. The bottom surfaces of the bottom wall portion 212a and the flange portion 213a are substantially flat, and only the outer peripheral portion of the flange portion 213a is slightly displaced upward. The grounding member 200a can be formed of metal or resin, but in the present embodiment, as shown in FIG. 10, a metal such as aluminum is formed from the central cylinder portion 210a to the middle of the bottom wall portion 212a. It can be formed by integrally molding the remaining portion with a resin. By doing so, by using a pair of upper and lower bearings 250 and by forming the central cylinder portion 210a supported by the bearing 250 with metal, the rotatable support state of the grounding member 200a is more stable. Not only can it be made, but it can also be made lighter.

The outer diameter of the flange portion 213a of the grounding member 200a is smaller than the outer diameter of the flange portion 160 of the holding member 100, and is larger than 1/2, preferably 2/3 of the outer diameter of the flange portion 160. In a larger range, the appropriate dimensions are set based on the following ideas.

That is, since there is a vertical difference between the nylon cord 40a and the bottom surface of the grounding member 200a, in order to cut the weed to be cut at the root thereof, as shown in FIG. 12, the peripheral portion of the grounding member 200a is grounded. It is necessary to move the rotary blade A1 while tilting it by, for example, 10 ° to 15 ° with respect to the ground while it is in contact with the ground. At that time, the outer diameter of the flange portion 213a of the grounding member 200a is set so that the flange portion 160 of the holding member 100 that rotates at high speed together with the nylon cord 40a does not come into contact with the ground.

Next, in the rotary blade A1 of the present embodiment, as the nylon cord 40a, a long nylon cord cut to a predetermined length is used. That is, as well shown in FIGS. 11 and 13, both ends of the nylon cord 40a are inserted into the holes 132 of the third and fourth cord connecting portions 143 and 144, and both ends thereof pass through the cord insertion space 130. The hanging portion 150 is hung around and pulled out outward in the radial direction of the holding member 100. As a result, the two nylon cords 40a whose base ends are connected to the third and fourth cord connecting portions 143 and 144 are the same as those extending from the same position in the circumferential direction of the holding member 100. Since the two nylon cords 40a are connected to one on the outer surface side of the third and fourth cord connecting portions 143 and 144, they will not come off carelessly. Further, the length of one nylon cord to be used so that the two nylon cords 40a extend in the radial direction of the holding member 100 and the tip thereof protrudes from the outer edge of the flange portion 160 by about 30 to 60 mm. Is set.

When the mowing work is performed for a certain period of time using this rotary blade A1 for a mowing machine, the tip of the nylon cord 40a is worn and the length extending from the flange portion 160 gradually becomes shorter. In that case, the thickness is thick. The nylon cord is pulled out by pulling the portion of the upper surface of the annular portion 120 that crosses between the third cord connecting portion 143 and the fourth cord connecting portion 144, and the holes 132 of the second and third cord connecting portions 142 and 143 are inserted. Both ends of the nylon cord 40a are inserted, the cord insertion space 130 is passed through, and the hanging portion 150 is hung and pulled out in the radial direction of the holding member 100. As a result, the extension length of the nylon cord 40a from the outer edge of the flange portion 160 can be extended by a length corresponding to the distance between the adjacent cord connecting portions 141, 142, 143, 144. Then, when the tip of the nylon cord 40a is worn again and the extension length from the flange portion 160 is shortened, the nylon cord 40a is pulled out in the same manner as described above, and both ends are connected to the first and second cords. It may be inserted into each of the holes 132 of 141 and 142, and the hooking portion 150 may be hooked and pulled out in the radial direction in the same manner as described above.

The rotary blade A1 for a mower of this embodiment has a point in which a plurality of nylon cords 40a extend from the same position in the circumferential direction of the holding member 100, and is rotatable relative to the rotary blade mounting shaft 14. It is common with the rotary blade A for a mower according to the reference example in that it includes a grounding member 200a. Therefore, even when the mowing work is performed using the rotary blade A1 for the mowing machine of the present embodiment, the mowing work is performed using the rotary blade A for the mowing machine of the reference example, as described above. Weeds can be cut very efficiently.

In particular, the rotary blade A1 for a mower of the present embodiment has a large outer diameter of the grounding member 200a as a predetermined value and a wide flat area on the bottom surface thereof, so that the grounding member 200a is grounded. While doing so, it can be stably moved along the ground. Further, since the outer diameter of the grounding member 200a is large as predetermined as described above, as shown in FIG. 12, the rotary blade A1 is placed on the ground, for example, 10 to 15 while grounding the peripheral edge of the grounding member 200a. Even when tilting and cutting weeds and other cutting objects from their roots, the flange portion 160, which rotates at high speed together with the nylon cord 40a, inadvertently comes into contact with the ground and the rotation of the rotary blade A1 slows down. It can be effectively avoided and efficient mowing work can be continued.

Of course, the scope of the present invention is not limited to the above-described embodiment, and all modifications within the scope described in each claim are included in the scope of the present invention.

The specific configuration for extending the plurality of nylon cords 40, 40a (cord-shaped cutting blades) from the same location in the circumferential direction of the holding member 100 is not limited to that of the embodiment.

In each embodiment, four cord connecting portions 141, 142, 143, 144 are provided side by side in the circumferential direction, but the number of the cord connecting portions may be 2 or more.

In the embodiment, of the four cord connecting portions 141, 142, 143, 144, two cord connecting portions are used, and the base ends of the two nylon cords 40 are connected to two adjacent cord connecting portions to be the same. Although the example in which the tip side of the two nylon cords 40 extends from the hanging portion 150 of the above is described, three nylon cords 40 are connected to the adjacent three cord connecting portions by using three cord connecting portions. It may be connected so that the tip side of the three nylon cords 40 extends from the same hanging portion 150.

Further, the holding member 100 in the embodiment is designed to hold the base end side of the nylon cord 40 having a predetermined length, but the holding form of the nylon cord is not limited to this. For example, as shown in Patent Document 2 (International Publication WO2007 / 023758), as a holding member, a long nylon cord is wound and held, and a plurality of the holding members are used. Nylon cord may be wound and held so that two or more nine cords can be derived from one lead-out hole.

Further, the mower B to which the rotary blade A1 of the present invention is attached is not limited to the one having the rotary blade attachment shaft 14 at the tip of the operation pipe 12 as shown in FIGS. 1 and 3. The rotary blade of the present invention is also attached to a so-called self-propelled mower having a power source such as an engine and a rotary blade mounting shaft that is rotationally driven by this power source on a frame that has wheels and can move on the ground. Can be used.

A1 rotary blade B mower 40, 40a Nylon cord (cord-shaped cutting member)
14 Rotating blade mounting shaft 100 Holding member 160 Flange part 200a Grounding member

Claims (2)

A holding member that is attached to the rotary blade mounting shaft of the mower and rotated.
A rotary blade for a mower, comprising a cord-shaped cutting member whose base end side is held by the holding member and whose tip end side extends outward in the radial direction of the holding member.
A flange portion Ru extending radially outward of the outer periphery of the holding member integrally with the holding member in the lower than the cord-shaped cutting member, the cutting target is radially inner than the outer periphery of the flange portion It enters toward includes those that prevent the approaching to the outer periphery of the holding member,
Below the holding member and the flange portion, it is rotatable relative to the holding member and the flange portion about the rotation axis of the holding member, and is smaller than the outer diameter of the flange portion. including a ground member bottom surface is a substantially planar portion as well as have a outside diameter of greater than 1/2 of the outer diameter of the flange portion, the outer diameter of the flat portion, the outer diameter of the flange portion A rotary blade for mowing machines, which is characterized by being larger than 1/2 . It is equipped with a power source and a rotary blade mounting shaft that is rotationally driven by the power of this power source.
A mower, characterized in that the rotary blade for a mower according to claim 1 is attached to the rotary blade mounting shaft.

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