JP6951217B2 - lawn mower - Google Patents

Description

The present invention relates to a lawnmower having a blade that rotates about a horizontal axis.

In the following Patent Documents 1 and 2, a blade unit having a fixed blade and a rotary blade is detachably configured with respect to the main body so that the fixed blade and the rotary blade can be exchanged as a set with respect to the main body. The main body is equipped with a drive source for driving the rotary blade, and the power of the drive source is supplied to the drive side pulley attached to the main body side and the driven side pulley attached to the rotating shaft of the blade unit. , The belt wound between both pulleys transmits to the rotating shaft to drive the rotary blade to rotate.

When removing the blade unit from the main body, it is necessary to remove the belt from both pulleys. Further, when attaching the blade unit to the main body, it is necessary to attach belts to both pulleys. However, the work of attaching and detaching this belt is not easy.

Special Publication No. 56-49523 Jitsukaisho 51-113061

Therefore, the present invention has been made in view of the above-mentioned conventional problems, the blade unit is detachable from the main body, and power is transmitted from the drive source of the main body to the blade of the blade unit by the endless power transmission body. It is an object of the present invention to provide a lawnmower capable of easily attaching and detaching an endless power transmission body when attaching and detaching a blade unit.

The present invention has been made to solve the above problems, and the lawn mower according to the present invention is a lawn mower in which a blade unit is detachably attached to a main body, and the blade unit is horizontal. A rotating shaft extending in a direction, a blade rotating integrally with the rotating shaft, and a driven side rotating wheel mounted on one end of the rotating shaft are provided, and the main body includes a driving source for driving the blade and the driving. A drive-side rotary wheel for transmitting the rotation of the source is provided, and an endless power transmitter is wound between the drive-side rotary wheel and the driven-side rotary wheel, and the blade unit is on the drive side. It is configured to be movable with respect to the main body so that the center-to-center distance between the rotating wheel and the driven side rotating wheel changes, and the main body presses the blade unit in a predetermined direction so that the center-to-center distance increases. A pressing portion that can be moved between the pressing position to be pressed and a pressing release position that releases or reduces the pressing force, and a mowing corresponding to the pressing position of the pressing portion in order to move the pressing portion to the pressing position and the pressing release position. It is equipped with an operation unit that can switch between the working position and the unit attachment / detachment position corresponding to the pressing release position of the pressing unit. The blade unit is held in a predetermined cutting state by the balance between the pressing force of the unit and the tension of the power transmission body, and when the operation unit is positioned at the unit attachment / detachment position, the power transmission body is in a loosened state. ..

In the lawn mower having this configuration, when the operating portion is set to the mowing work position, the pressing portion is set to the pressing position, the distance between the centers is relatively large, and the power transmission body is in a stretched state. Then, the blade unit is held in a predetermined cutting state by the balance between the pressing force of the pressing portion and the tension of the power transmission body. On the other hand, when the operation unit is in the unit attachment / detachment position, the pressing unit is in the pressing release position, the distance between the centers becomes relatively small, and the power transmission body becomes loose. Therefore, the loosened power transmitter can be easily removed.

In particular, it is preferable to provide a lock portion that prevents the operation portion located at the cutting work position from moving to the unit attachment / detachment position. By providing the lock unit in this way, the operation unit can be moved to the unit attachment / detachment position by vibration, the operation unit can be moved to the unit attachment / detachment position by contacting another object, or the operation unit can be moved to the unit attachment / detachment position. There is no need to accidentally move the unit to the attachment / detachment position by hitting the body. Therefore, the safety is improved and the lawn mower can be handled with peace of mind.

In addition, it is equipped with a removable cover that covers the driving side rotating body, the driven side rotating body, and the power transmission body, and it is not possible to switch from the cutting work position of the operation unit to the unit attachment / detachment position with the cover attached. It is preferable that the cover can be removed to enable the switching operation from the cutting work position of the operation unit to the unit attachment / detachment position. In this case, the cover may or may not cover the operation portion. For example, in a configuration in which the cover covers the operation unit, it is impossible to operate the operation unit itself, and it is possible to prevent another object from colliding with the operation unit. Further, even if the cover does not cover the operation unit, the operation unit cannot be moved to the unit attachment / detachment position because the cover is an obstacle, for example. Then, by going through one process of removing the cover, careless switching operation of the operation unit is prevented, switching operation of the operation unit is reliable, and the safety of the blade unit attachment / detachment work is enhanced. ..

In particular, it is preferable that the cover is provided with a lock portion that prevents the operation portion located at the cutting work position from moving to the unit attachment / detachment position. It is not necessary to provide the lock portion separately from the cover, and the lock portion can be automatically unlocked by removing the cover.

As described above, the power transmission body can be loosened by reducing the distance between the centers by switching the operation unit, and the loosened power transmission body can be easily removed.

The perspective view which shows the lawn mower in one Embodiment of this invention. The front view which shows the lawn mower in one Embodiment of this invention. Bottom view of the main part of the lawn mower. Front view of the main part showing the state where the cover of the lawn mower is removed and the belt is stretched. FIG. 4A is a cross-sectional view taken along the line AA of FIG. BB sectional view of FIG. A front view of a main part corresponding to FIG. 4 showing a state in which the belt of the lawn mower is loosened. FIG. 7 is a cross-sectional view taken along the line DD of FIG. FIG. 5 is a cross-sectional view of a main part CC of FIG. FIG. 9 is a cross-sectional view of a main part corresponding to FIG. 9, showing a state in which the belt is loosened. (A) to (c) are enlarged views of the main parts of the lawn mower. FIG. 5 is a cross-sectional view corresponding to FIG. 5 showing a blade unit of the lawn mower. The schematic view corresponding to FIG. 4 which shows the state in the process of mounting the blade unit of the lawn mower on the main body frame. FIG. 6 is a schematic view corresponding to FIG. 6 showing a state in which the blade unit of the lawn mower is being mounted on the main body frame. (A) and (b) are enlarged views of the main part of the lawn mower. The front view which shows the lawn mower in another embodiment of this invention. The front view which shows the lawn mower in another embodiment of this invention. It is a front view which shows the main part of the lawn mower in another embodiment of this invention, (a) shows the state which the belt is stretched, (b) shows the state which the belt is loosened. It is a front view which shows the main part of the lawn mower in another embodiment of this invention, (a) shows the state which the belt is stretched, (b) shows the state which the belt is loosened. It is a front view which shows the main part of the lawn mower in another embodiment of this invention, (a) shows the state which the belt is stretched, (b) shows the state which the belt is loosened. It is a front view which shows the main part of the lawn mower in the same embodiment, and shows the state in which the belt is stretched. In the cross-sectional view taken along the line EE of FIG. 21, (a) shows the relationship between the right side plate and the blade unit, and (b) shows the relationship between the left side plate and the blade unit.

Hereinafter, the lawn mower according to the embodiment of the present invention will be described with reference to FIGS. 1 to 15. 1 and 2 show the overall appearance of the lawnmower. In the following explanation, the front side where the worker is located is the rear side, the side opposite to the front side, the direction of travel of the lawnmower is the front side, and the left side and the right side are based on the case of viewing from the front side. do. Therefore, FIG. 1 is a perspective view seen from the front left. FIG. 2 is a view from the left side and shows the left side surface of the lawn mower.

<Overall configuration>
The lawn mower in this embodiment is an electric lawn mower provided with an electric motor 30 as a drive source. It may be a type having a power cord (not shown) or a type not having a power cord, and therefore may be a rechargeable type. Further, the structure includes a front wheel 1 and a rear wheel 2, and is a hand-push running type in which an operator stands on the rear side, holds the handle 3, and pushes the lawn toward the front side to mow the lawn. The blade has a structure that rotates around an axis in the horizontal direction, and specifically, has a structure that rotates around an axis in the left-right direction. As a grass collecting device for collecting cut grass, a grass collecting box 4 as shown by a two-dot chain line in FIG. 1 can be detachably attached to the rear part of the main body 6.

<Blade unit 7>
The blades include a rotary blade 11 that cuts the lawn between the fixed blade 10 and the reel blade, and a lawn called thatch that has dead roots, stems, and leaves of the lawn accumulated in the lawn. There are a thatching blade for removing, a root cutting blade for cutting old roots and stems by making a vertical cut in the grass, and the like, but in this embodiment, the rotary blade 11 will be described as an example. However, it may be a thatching blade, a root cutting blade, or the like. Further, since the blade is replaceable, the reel blade may be replaced with a thatching blade or the like as appropriate. The lawn mower includes a main body 6 and a blade unit 7 detachably attached to the main body 6, and the blade unit 7 includes a rotary blade 11 and a fixed blade 10. Therefore, the rotary blade 11 and the fixed blade 10 can be attached and detached as a set by attaching and detaching the blade unit 7, and can be replaced with a new one as a set. Then, it can be replaced with a blade unit 7 of a thatching blade or a blade unit 7 of a root cutting blade. The blade unit 7 in the present embodiment is a reel blade type, but may be a thatching blade type or a root cutting blade type.

FIG. 12 shows the blade unit 7 in this embodiment as a single unit. The blade unit 7 includes a rotating shaft 12 extending in the left-right direction, a blade frame that rotatably supports both ends of the rotating shaft 12, and a driven side rotating body mounted on one end of the rotating shaft 12. It includes a side pulley 13, a rotary blade 11 that rotates integrally with the rotary shaft 12, and a fixed blade 10 that is attached and fixed to a blade frame and cuts grass together with the rotary blade 11. The rotary blades 11 extend spirally, and a plurality of rotary blades 11 are provided. The fixed blade 10 is fixed at a position close to the rotation trajectory of the rotary blade 11. The blade frame consists of a pair of left and right side plates 14 and 15, an upper plate 16 that connects the upper ends of the left and right side plates 14 and 15 to the left and right, and lower portions of the left and right side plates 14 and 15 with the rear portions left and right. It is provided with a support column 17 for connecting. The left and right side plates 14, 15 and the upper plate 16 are integrally formed as one member and are made of sheet metal, but they may be formed as separate members and connected by screws or the like. The left and right side plates 14, 15 and the upper plate 16 have a gate shape that opens downward as a whole. The rear portion of the fixed blade holder 18 is rotatably supported by the support column 17, and the fixed blade 10 is screwed to the fixed blade holder 18. Arms 18a extend toward the front side of each of the left and right ends of the fixed blade holder 18. Adjusting bolts 19 are inserted from below into the tips of the left and right arm portions 18a, respectively, and the adjusting bolts 19 are screwed to the side plates 14 and 15. A coil spring 20 is arranged between the arm portion 18a of the fixed blade holder 18 and the side plates 14 and 15, and the adjusting bolt 19 is inserted through the coil spring 20. By increasing or decreasing the screwing amount of the adjusting bolt 19, the fixed blade 10 can be swung up and down via the fixed blade holder 18, and the gap between the fixed blade 10 and the rotary blade 11 can be adjusted. ..

Both ends of the rotating shaft 12 are supported by the left and right side plates 14 and 15 of the blade frame via a bearing 21 and a bearing holder 22, respectively. The left end, which is one end of the rotating shaft 12, is projected sideways through the left side plate 14, and the driven pulley 13 is attached to the protruding portion, and the driven pulley 13 is the rotating shaft 12. It rotates together with. The right end, which is the other end of the rotating shaft 12, is supported inside the right side plate 15 without inserting the right side plate 15. The rotary blade 11 is attached to the rotary shaft 12 and rotates inside the left and right side plates 14, 15 and the upper plate 16 of the blade frame.

As shown in FIGS. 3, 5 and 12, an inner cover 23 is provided between the left side plate 14 and the driven side pulley 13. The inner cover 23 is attached to the left side plate 14. As shown in FIG. 5, the inner end portion of the side wall portion 61b of the outer cover 61, which will be described later, is joined to the peripheral edge portion of the inner cover 23 from the outside. The inner cover 23 fills the gap between the outer cover 61 and the left side plate 14, and dust and turf enter the outer cover 61 through the gap between the outer cover 61 and the left side plate 14, and the driven side pulley. Prevents it from adhering to 13 or the belt. The outer cover 61 is not shown in FIG. Further, the inner cover 23 is not shown in FIGS. 4, 7, and 13.

A pair of front and rear engaging pins 24 are attached to the side plates 15 on the right side of the blade frame. The engaging pin 24 is the blade side engaging portion. The engaging pin 24 projects laterally from the side plate 15. As shown in FIG. 15B, the engaging pin 24 is a stepped pin. The engaging pin 24 is located on the most proximal side, and has a small diameter mounting shaft portion 24a that is inserted through the side plate 15 and fixed by caulking, and the tip side of the mounting shaft portion 24a and the center of the engaging pin 24. A large-diameter intermediate shaft portion 24b that is located on the side plate 15 and abuts on the outer surface of the side plate 15, and a small-diameter engaging shaft portion that is located on the tip end side of the intermediate shaft portion 24b and is located on the most tip side of the engagement pin 24. It has. A tapered portion 24d is formed at the tip of the engaging shaft portion, and therefore the engaging shaft portion is composed of a tapered portion 24d and a straight portion 24c. Of the total length of the engaging pin 24, the intermediate shaft portion 24b and the engaging shaft portion project to the outside of the side plate 15. The front and rear engaging pins 24 are in the same vertical position with each other. The engaging pin 24 is located higher than the center of the rotating shaft 12.

A pair of front and rear projecting portions 25 and 26 are provided on the left side plate 14 of the blade frame toward the side. The projected protrusions 25 and 26 for being guided are formed at the front end portion and the rear end portion of the side plate 14 on the left side of the blade frame, respectively. The front and rear guided protrusions 25 and 26 have the same height in the vertical direction, and are located at the center of the left side plate 14 in the vertical direction. The protrusions 25 and 26 for being guided are located above the rotating shaft 12.

A locked plate 27 is screwed to the vicinity of the left end of the upper plate 16 of the blade frame. The left end portion 27a of the locked plate 27 is separated upward from the upper plate 16. The left end portion 27a of the locked plate 27 is configured as a fall prevention locked portion for preventing the blade unit 7 from falling in the unlikely event that the belt 8 is cut.

<Main body 6>
The main body 6 includes a metal main body frame, a resin housing attached to the main body frame so as to cover the outside of the main body frame, a motor 30 which is a drive source for driving the rotary blade 11, and the motor. It includes a drive-side pulley 31 which is a drive-side rotating body for transmitting the rotation of 30, a handle 3 which can rotate in the front-rear direction, and front wheels 1 and rear wheels 2 which are attached to a main body frame. The front wheels 1 are provided in pairs on the left and right, and the rear wheels 2 are provided with one roller-shaped one that is long in the left-right direction. The front wheel 1 is attached to the main body frame via the wheel link 32. The blade unit 7 is located between the front wheels 1 and the rear wheels 2. The handle 3 is the base end portion and the front end portion is rotatably supported on the upper portion of the rear portion of the main body frame, and the operator is the tip end portion of the handle 3 and grips the rear end portion to mow the lawn. Push the machine forward.

The main body frame includes a pair of left and right side plates 33, 34 forming the left and right side surfaces of the main body frame, a connecting member 35 for connecting the left and right side plates 33, 34, and a motor for attaching the motor 30. It is provided with a holder 36. The left and right side plates 33 and 34 are arranged in parallel so as to be separated from each other, and are connected and integrated to the left and right by a connecting member 35. The main part of the blade unit 7 is located between the left and right side plates 33 and 34. 4, 7 and 13 are views of the left side plate 33 viewed from the outside, and FIGS. 6 and 14 are views of the right side plate 34 viewed from the inside. The side plates 33 and 34 are made of sheet metal. The motor holder 36 is located between the side plates 33 and 34 so as to connect the left and right side plates 33 and 34, and is screwed to the side plates 33 and 34 from the outside, respectively. The motor holder 36 is located at the front portion and the upper portion of both side plates 33 and 34.

The motor 30 is attached so as to be placed on the upper side of the motor holder 36. The main shaft 37, which is the rotation axis of the motor 30, extends along the horizontal direction, and specifically extends in the left-right direction. Therefore, the main shaft 37 of the motor 30 and the rotating shaft 12 of the rotary blade 11 both extend in the left-right direction and are parallel to each other. The spindle 37 of the motor 30 is located on the front side and the upper side of the rotary shaft 12 of the rotary blade 11. The lower half region of the motor 30 is located below the upper ends of the left and right side plates 33, 34, and the upper half region of the motor 30 projects upward from the upper ends of the left and right side plates 33, 34. The tip of the main shaft 37 of the motor 30 faces to the left and protrudes sideways from the left side plate 33, which is one of the left and right side plates 33, 34, and the drive side pulley 31 protrudes from the protruding portion. It is installed. Therefore, the drive side pulley 31 is located outside the left side surface portion of the main body frame. Further, in a state where the blade unit 7 is attached to the main body 6, the driven side pulley 13 is located at the same left-right direction position as the drive side pulley 31.

A belt 8 as an endless power transmitter is wound between a drive-side pulley 31 provided on the main body 6 and a driven-side pulley 13 provided on the blade unit 7. Therefore, the belt 8 is also located outside the left side surface portion of the main body frame. A plurality of V-grooves are formed in each of the drive-side pulley 31 and the driven-side pulley 13, and a plurality of V-grooves are also formed on the surface of the belt 8 corresponding to the plurality of V-grooves. The driven side pulley 13 has a larger diameter than the driving side pulley 31. Therefore, the rotation of the motor 30 is decelerated at a predetermined reduction ratio between the drive side pulley 31 and the driven side pulley 13 and transmitted to the rotation shaft 12. The center of the driven-side pulley 13 is located diagonally rearward on the lower side with respect to the center of the drive-side pulley 31. The straight line 38 connecting the center of the driven side pulley 13 and the center of the driving side pulley 31 is inclined at a predetermined angle with respect to the vertical direction, and the inclined angle is less than 45 degrees, specifically about 30 degrees. be.

<Right side plate 34>
Of the left and right side plates 33 and 34, the right side plate 34 oscillatingly supports the blade unit 7. That is, the main body frame cantileverly supports the right end portion of the blade unit 7 on the right side plate 34. As shown in FIG. 14, a pair of front and rear engaging holes 39 are formed through the right side plate 34 at a substantially central portion in the vertical direction. The engaging hole 39 is the main body side engaging portion. The front and rear engaging holes 39 have the same vertical positions. The front and rear engaging holes 39 engage with the engaging shafts of the front and rear engaging pins 24 of the blade unit 7 in the left-right direction. That is, as shown in FIG. 15A, the engaging shafts of the front and rear engaging pins 24 of the blade unit 7 are inserted into the front and rear engaging holes 39 from the inside. One of the front and rear engaging holes 39 is a round hole, and the other is an elongated hole long in the front-rear direction. The front and rear engaging holes 39 function as positioning holes for determining the mounting position of the blade unit 7.

Further, the front and rear engaging holes 39 serve as fulcrums when the main body 6 swings and supports the blade unit 7. There is a slight radial gap between the engaging hole 39 and the straight portion 24c of the engaging shaft portion of the engaging pin 24 as a rattling. The length of the straight portion 24c of the engaging shaft portion of the engaging pin 24 is short, and the wall thickness of the right side plate 34 is also thin. Of the total length of the engaging shaft portion of the engaging pin 24, the length of the straight portion 24c excluding the tapered portion 24d is shorter than the wall thickness of the right side plate 34. The blade unit 7 is cantilevered and supported by the side plate 34 on the right side at a portion very short with respect to the blade unit 7, which is a straight portion 24c of the engaging shaft portion of the engaging pin 24. Therefore, the blade unit 7 rattles mainly in the vertical direction with the engaging hole 39 and the straight portion 24c of the engaging pin 24 as fulcrums due to a slight gap between the engaging hole 39 and the straight portion 24c of the engaging pin 24. It has a structure that can swing as.

As shown in FIGS. 6 and 14, on the inner surface of the right side plate 34, a pair of front and rear guide protrusions 40 and 41 for guiding the blade unit 7 from both front and rear sides when attaching and detaching the blade unit 7 are provided. Is projected. The front and rear guide protrusions 40 and 41 guide the front end portion and the rear end portion of the side plate 15 on the right side of the blade frame, respectively. The guide protrusions 40 and 41 are located below the engaging holes 39. The front guide protrusion 40 is located on the front side of the front engagement hole 39, and the rear guide protrusion 41 is located on the rear side of the rear engagement hole 39. A stopper 42 is projected inward from the upper part of the side plate 34 on the right side. In the mounted state of the blade unit 7 as shown in FIG. 6, the right end portion of the upper plate 16 of the blade frame faces the lower side of the stopper 42 with a slight gap.

<Left side plate 33>
As shown in FIGS. 4 and 13, a notch 45 having a large notch on the upper side and an opening on the lower side is formed in the lower central portion of the left side plate 33. The cutout portion 45 is a relief portion for avoiding interference with the shaft portion of the driven side pulley 13 of the blade unit 7. At the front and rear notch edges facing the notch 45, a straight portion 46 extending in the vertical direction and a straight portion 46 extending below the straight portion 46 are extended, and the distance between the front and rear gradually increases toward the lower side. An inclined portion 47 is provided. The notch edge portion functions as a guide when mounting the blade unit 7. When the blade unit 7 is mounted on the main body 6, a pair of front and rear guided protrusions 25, 26 are projected laterally from the left end of the blade unit 7 as shown in FIGS. 3 and 4. Is guided by the inclined portions 47 of the front and rear cutout edges to reach the straight portion 46. With the blade unit 7 attached, the guided protrusion 25 on the front side of the blade unit 7 abuts on the straight portion 46 of the notch edge on the front side from the rear side, and the cover on the rear side of the blade unit 7. The guide protrusion 26 faces the front side of the straight portion 46 of the notch edge portion on the rear side with a slight gap. A nut 48 for attaching a cover is welded to a substantially central portion of the outer surface of the left side plate 33. A lever stopper 49 for stopping the rotation of the switching lever 50, which will be described later, is formed at the upper end of the rear portion of the left side plate 33.

<Switching lever 50>
The main body 6 includes a switching lever 50 as an operation unit that is switched when the blade unit 7 is attached / detached. The switching lever 50 is rotatably supported by the left side plate 33. The switching lever 50 has a shape in which the base end portion is supported by the left side plate 33 and extends linearly from the base end portion to the tip end portion. The switching lever 50 is located outside the left side plate 33. The switching lever 50 rotates in parallel with the left side plate 33. Therefore, the switching lever 50 rotates around the axis in the horizontal direction, and specifically, rotates up and down around the axis in the left-right direction. The rotation shaft 51, which is the rotation center of the switching lever 50, is parallel to the rotation shaft 12 of the rotary blade 11 and the spindle 37 of the motor 30. The rotation shaft 51 of the switching lever 50 is located above the rotation shaft 12 of the rotary blade 11 and slightly below the main shaft 37 of the motor 30. Further, the rotation shaft 51 of the switching lever 50 is located on the rear side of the main shaft 37 of the motor 30 and on the rear side of the rotation shaft 12 of the rotary blade 11. The switching lever 50 can be reciprocally rotated within a predetermined angle range. The rotatable angle range of the switching lever 50 is less than 360 degrees, specifically 180 degrees or less, and in the present embodiment, it is approximately 90 degrees to 100 degrees.

4 and 7 are views of the left side plate 33 viewed from the outside, and FIGS. 5 and 8 are cross-sectional views when the left side plate 33 is cut at a cut surface passing through the rotation shaft 51 of the switching lever 50. 9 and 10 are views of the switching lever 50 viewed from the inside of the left side plate 33. 4, 5 and 9 show the position of the switching lever 50 in the normal use state in which the blade unit 7 is mounted and the cutting work is performed, and FIGS. 7, 8 and 10 show the blade unit. The position of the switching lever 50 when attaching / detaching 7 to / from the main body 6 is shown. The position of the switching lever 50 shown in FIGS. 4, 5 and 9 is referred to as a cutting work position, and the position of the switching lever 50 shown in FIGS. 7, 8 and 10 is referred to as a unit attachment / detachment position.

The switching lever 50 is in a horizontal posture tilted backward at the cutting work position, and is in a vertical posture standing upward at the unit attachment / detachment position. The switching lever 50 comes into contact with the lever stopper 49 of the left side plate 33 from above at the cutting work position. Therefore, when the switching lever 50 is viewed from the outside of the left side plate 33 in the axial direction of the rotating shaft 51, the lever stopper 49 prevents further clockwise rotation of the switching lever 50. On the other hand, the switching lever 50 can rotate a predetermined angle counterclockwise when viewed from the front beyond the vertical posture as shown in FIG. 7, and finally the switching lever 50 is in a position where it comes into contact with a contact portion (not shown) provided in the main body 6. Stop at. Therefore, when the blade unit 7 is attached / detached, the switching lever 50 may be positioned in contact with the abutting portion, and may be located in the vicinity of the unit attachment / detachment position as shown in FIG. 7 or the like. When the switching lever 50 is located at the unit attachment / detachment position, most of the total length of the switching lever 50 protrudes upward from the upper end of the left side plate 33.

<Pressing cam 52>
A pressing cam 52 is provided at the base end of the switching lever 50. The pressing cam 52 rotates integrally with the switching lever 50. The pressing cam 52 may be integrally formed as one component at the base end portion of the switching lever 50, but in the present embodiment, the pressing cam 52 is configured separately from the switching lever 50. The rotation shaft 51 of the switching lever 50 inserts the left side plate 33 inward, and the cam member 53 is screwed to the rotation shaft 51 inside the left side plate 33. Therefore, the switching lever 50, the cam member 53, and the rotation shaft 51 rotate integrally. A pressing cam 52 is formed on the peripheral surface of the cam member 53.

The pressing cam 52 is a cam centered on the rotation center of the switching lever 50, and the distance from the center changes along the circumferential direction. The blade unit 7 is a cam follower and is pushed downward by the pressing cam 52 to move. Specifically, the pressing cam 52 presses the left end portion of the upper plate 16 of the blade frame of the blade unit 7 from above. When the switching lever 50 is located at the unit attachment / detachment position as shown in FIG. 10, the pressing cam 52 is in a state of being separated upward without contacting the left end portion of the upper plate 16. However, the pressing cam 52 may be in contact with the upper plate 16 at the unit attachment / detachment position. When the switching lever 50 is rotated toward the cutting work position side from there, the pressing cam 52 starts to come into contact with the left end portion of the upper plate 16 as shown in FIG. 11A. In FIG. 11, the center line of the switching lever 50 is shown by a chain double-dashed line.

Further, when the switching lever 50 is rotated toward the cutting work position side, the pressing cam 52 presses the left end portion of the upper plate 16 downward, and the blade unit 7 is pressed against the right side plate 34. It is rotated downward with the engaging hole 39 as a fulcrum. The state shown in FIG. 11B is a state when the switching lever 50 reaches the position immediately before the cutting work position, and the pressing cam 52 moves the left end portion of the upper plate 16 to the lowermost side. It is the state when the upper plate 16 is left, and is the state of the lowest point when the left end portion of the upper plate 16 is displaced to the lowermost side. In this state, the blade unit 7 is in a state of being slightly tilted downward from the horizontal state. The state shown in FIG. 11C is the state when the switching lever 50 is in the cutting work position, and the left end portion of the upper plate 16 is a position slightly returned to the upper side from the lowest point in FIG. 11B. It is in. In this state, the blade unit 7 is in a horizontal state.

In the present embodiment, the pressing cam 52 constitutes a pressing portion that presses the blade unit 7 in a predetermined direction so that the distance between the centers of the driving side pulley 31 and the driven side pulley 13 becomes large. The position of the pressing cam 52 shown in FIGS. 9 and 11C is the pressing position where the pressing cam 52 presses the blade unit 7 downward so that the distance between the centers becomes large. The position of the pressing cam 52 shown in FIG. 10 is the pressing release position for releasing or reducing the pressing force. The position of the pressing cam 52 shown in FIG. 11B is set as the maximum displacement position. As the switching lever 50 rotates from the cutting work position to the unit attachment / detachment position, the pressing cam 52 rotates from the pressing position to the pressing release position.

<Locking part 54 for fall prevention>
The cam member 53 is provided with a fall prevention locking portion 54 projecting inward, that is, toward the right side. The fall prevention locking portion 54 projects inward from the inner surface of the cam member 53 along the axial direction of the rotating shaft 51, and is located inside the pressing cam 52. The fall prevention locking portion 54 rotates integrally with the switching lever 50. When the switching lever 50 is located at the cutting work position as shown in FIGS. 5 and 9, the fall prevention locking portion 54 is the left end of the locked plate 27 attached to the upper plate 16 of the blade unit 7. It is located below the portion 27a and is in a state of being inserted between the left end portion 27a of the locked plate 27 and the upper plate 16. The side surface of the fall prevention locking portion 54 near the center of the rotation shaft 51 faces the lower side of the left end portion 27a of the locked plate 27 via a gap to prevent the fall from falling far from the center of the rotation shaft 51. The side surface of the locking portion 54 faces the upper side of the upper plate 16 through a gap. If the belt 8 should be cut while the blade unit 7 is attached to the main body 6, the locked plate 27 is locked to the fall prevention locking portion 54 to prevent the blade unit 7 from falling. Will be done. When the switching lever 50 is located at the unit attachment / detachment position as shown in FIGS. 8 and 10, the fall prevention locking portion 54 is moved from between the left end portion 27a of the locked plate 27 and the upper plate 16 to the rear side. It comes out and is in a state of being retracted from the locked plate 27.

<Protruding piece 55>
The cam member 53 is provided with a projecting piece portion 55 on the outside, that is, on the left side of the pressing cam 52. The projecting piece portion 55 is formed adjacent to the outside of the pressing cam 52 and projects radially outward from the pressing cam 52. The projecting piece portion 55 has a predetermined thickness along the axial direction of the rotating shaft 51, and the thickness is the distance between the left side plate 33 and the left side plate 14 of the blade frame. Approximately equal to or slightly thinner than the distance. When the switching lever 50 is located at the unit attachment / detachment position as shown in FIG. 10, the projecting piece portion 55 is retracted upward from the blade unit 7 together with the pressing cam 52. When the switching lever 50 is located at the cutting work position as shown in FIGS. 9 and 5, the projecting piece portion 55 enters between the left side plate 33 and the left side plate 14 of the blade frame. The projecting piece portion 55 fills a gap between the left side plate 33 and the left side plate 14 of the blade frame, and a predetermined distance between the left side plate 33 and the left side plate 14 of the blade frame. Keep the distance. As a result, the engaging pin 24 of the blade unit 7 inserted into the engaging hole 39 of the right side plate 34 is prevented from coming off, and the rattling of the blade unit 7 is suppressed.

<Housing>
The main body 6 includes a resin housing that covers the outside of the main body frame. The upper part of the main body 6 is covered with a housing, while the lower part of the main body 6 is open without being covered with a housing. The housing includes a housing body 60 and an outer cover 61. The housing body 60 covers the outside of the body frame. The outer cover 61 is located on the outside of the housing body 60. Specifically, the outer cover 61 is located on the outside of the left side surface of the housing body 60. The outer cover 61 covers the drive side pulley 31, the driven side pulley 13, and the belt 8 from the outside, and also covers a predetermined range on the base end side of the switching lever 50 located at the cutting work position. The switching lever 50 located at the cutting work position has a substantially half area on the tip end side exposed without being covered by the outer cover 61, and a substantially half area on the base end side is covered by the outer cover 61.

The outer cover 61 is screwed from the outside to the nut 48 of the left side plate 33. The outer cover 61 can be removed from the left side plate 33 by loosening the screw 62 with a tool. When the outer cover 61 is removed, the drive side pulley 31, the driven side pulley 13 and the belt 8 are exposed, the predetermined range on the base end side of the switching lever 50 located at the cutting work position is also exposed, and the entire switching lever 50 is exposed. It will be exposed.

The outer cover 61 has a thin box shape, and is composed of an outer wall portion 61a and a side wall portion 61b extending inward from the peripheral edge portion of the outer wall portion 61a, and has a shape in which the inner surface is open. A notch 63 is formed at one of the entire circumferences of the side wall 61b, and the switching lever 50 is inserted through the notch 63, and the tip end side of the switching lever 50 projects to the outside of the outer cover 61. The width of the notch 63 is slightly wider than the width of the switching lever 50. Therefore, the switching lever 50 located at the cutting work position can only swing up and down slightly due to the gap between it and the notch 63, and the rotation to the unit attachment / detachment position is caused by the notch 63 of the outer cover 61. It is blocked by the upper part. Further, even if the switching lever 50 rotates slightly upward until it comes into contact with the upper portion of the notch 63, the pressing cam 52 does not reach the maximum displacement position and does not rotate at least beyond the maximum displacement position. In the present embodiment, the upper portion of the notch 63 of the outer cover 61 constitutes a lock portion that prevents the switching lever 50 located at the cutting work position from moving to the unit attachment / detachment position. The outer cover 61 is attached to the left side plate 33 by a screw 62 located at a substantially central portion of the outer wall portion 61a, but the side wall portion 61b on the front side of the outer cover 61 is a stepped portion of the housing body 60. Since it is in contact with 64, the rotation of the outer cover 61 around the screw 62 is prevented, and a predetermined mounting posture of the outer cover 61 is secured.

<Detachment work of blade unit 7>
When removing the blade unit 7 from the main body 6, it is preferable to tilt the lawn mower sideways so that the left side surface of the main body 6 faces upward. In that state, first loosen the screw 62 with a tool and remove the outer cover 61. When loosening the screw 62, the side wall portion 61b on the front side of the outer cover 61 is in contact with the step portion 64 of the housing body 60 from the rear side, so that the outer cover 61 does not rotate together with the screw 62 and the screw 62 can be easily screwed. The outer cover 61 can be removed by loosening it. Further, since the outer cover 61 does not rotate, the switching lever 50 does not rotate upward by being pushed by the notch 63 of the outer cover 61. In this way, the step portion 64 of the housing body 60 functions as a rotation prevention portion that prevents the outer cover 61 from rotating.

By removing the outer cover 61, the notch 63 of the outer cover 61 is automatically separated from the switching lever 50, and the rotation restriction of the switching lever 50 by the notch 63 of the outer cover 61 is released. Therefore, the switching lever 50 is rotated counterclockwise when viewed from the front to be positioned at the unit attachment / detachment position as shown in FIG. When the switching lever 50 is set to the unit attachment / detachment position, the pressing force that the pressing cam 52 pressed the blade unit 7 downward is released, so that the balance between the pressing force by the pressing cam 52 and the tension of the belt 8 is lost. The blade unit 7 is tilted upward by the tension of the belt 8 with the engaging hole 39 of the main body 6 as a fulcrum. When the blade unit 7 tilts upward with the engaging hole 39 of the main body 6 as a fulcrum, the distance between the centers of the drive side pulley 31 and the driven side pulley 13 becomes small, and the belt 8 becomes loose. Therefore, the loosened belt 8 can be easily removed. After removing the belt 8, the engaging pin 24 of the blade unit 7 is pulled out from the engaging hole 39 of the main body 6 by slightly lifting the blade unit 7, and the blade unit 7 is separated from the main body 6 as it is.

When the blade unit 7 is attached to the main body 6, the reverse procedure may be performed. That is, the engaging pin 24 of the blade unit 7 is inserted into the engaging hole 39 of the main body 6. Then, with the blade unit 7 tilted upward, the belt 8 is wound around the drive side pulley 31 and the driven side pulley 13 to obtain the state as shown in FIG. After that, the switching lever 50 is rotated clockwise when viewed from the front. The switching lever 50 is rotated until it comes into contact with the lever stopper 49. The position where the switching lever 50 comes into contact with the lever stopper 49 and stops is the cutting work position. By rotating the switching lever 50 to the cutting work position in this way, the belt 8 is automatically stretched, and the blade unit 7 is pushed down by the pressing cam 52 and automatically set to the normal use position at that position. Be retained. Then, the outer cover 61 is attached with the screw 62, and the drive side pulley 31, the driven side pulley 13, and the belt 8 are covered with the outer cover 61.

When the blade unit 7 is attached, the pressing cam 52 pushes the blade unit 7 downward. On the other hand, due to the tension of the belt 8, the blade unit 7 is pulled toward the drive side pulley side in the direction of the straight line 38 connecting the center of the drive side pulley 31 and the center of the driven side pulley 13. The lower pressing force of the pressing cam 52 and the vertical component of the tension of the belt 8 acting in the direction of the straight line 38 connecting the center of the driving side pulley 31 and the center of the driven side pulley 13 are balanced. .. In this way, the vertical swing of the blade unit 7 is regulated by the balance between the pressing pressure of the pressing cam 52 and the tension of the belt 8, and the blade unit 7 is held in the normal use position. Of the tension of the belt 8 acting in the direction of the straight line 38 connecting the center of the drive side pulley 31 and the center of the driven side pulley 13, the blade unit 7 receives a force on the front side due to the component force in the front-rear direction. , The guided protrusion 25 on the front side of the blade unit 7 is in contact with the straight portion 46 of the notch edge portion on the front side of the left side plate 33 from the rear side, and the balance of the forces in the front-rear direction is maintained. ..

As described above, the blade unit 7 is supported by the main body 6 so as to be swingable up and down, and the blade unit 7 swings up and down to move the center between the drive side pulley 31 and the driven side pulley 13. Since the distance is changed, the belt 8 can be loosened by bringing the driven side pulley 13 closer to the drive side pulley 31 when attaching and detaching the blade unit 7, and the loosened belt 8 is driven. It can be easily removed from the side pulley 13 and the drive side pulley 31. Further, the belt 8 can be easily wound with the driven pulley 13 close to the drive pulley 31.

Further, the blade unit 7 is supported by the side plate 34 on the right side of the main body frame so as to be swingable up and down on the right side opposite to the belt 8, and the support mechanism is the engagement hole 39 and the engagement pin. The slight gap between the 24 and the 24 is used. Therefore, the blade unit 7 can be swung with a simple structure, and the distance between the centers can be changed. Moreover, since the engagement pin 24 of the blade unit 7 is only engaged with the engagement hole 39 of the main body 6, the blade unit 7 can be engaged only by slightly moving the blade unit 7 to the left side. The pin 24 can be pulled out from the engaging hole 39 of the main body 6 to easily remove the blade unit 7 from the main body 6. Further, when the blade unit 7 is attached to the main body 6, it is only necessary to insert the engaging pin 24 of the blade unit 7 into the engaging hole 39 of the main body 6, so that the attachment work is easy. In this way, the blade unit 7 is swing-supported by utilizing the slight gap between the engagement hole 39 and the engagement pin 24, and the blade unit 7 is supported only by the right side plate 34. Since the blade unit 7 is supported, the blade unit 7 can be easily attached and detached.

Further, since the blade unit 7 is pressed by the pressing cam 52, the blade unit 7 can be easily attached and detached. Then, the belt 8 can be easily stretched or loosened by the pressing cam 52, and the belt 8 can be easily attached and detached. On the right side of the blade unit 7, the right side plate 34 supports the blade unit 7 so as to swing up and down, and on the left side of the blade unit 7, the belt 8 suspends and holds the blade unit 7. The pressing cam 52 pushes the blade unit 7 downward, and the blade unit 7 is maintained in a predetermined cutting state by the balance between the pressing pressure and the tension of the belt 8. Therefore, the structure is simple, and the blade unit 7 can be easily attached and detached. Further, although the pressing cam 52 is located at the pressing position in the mowing state, the pressing position is a position rotated beyond the maximum displacement position that causes the blade unit 7 to be maximally displaced downward. It is difficult for the cam 52 to return to the pressing release position side beyond the maximum displacement position, and a stable pressing state by the pressing cam 52 can be obtained. Furthermore, even if the belt 8 is cut, the blade unit 7 is caught by the fall prevention locking portion 54 and stops, so that the blade unit 7 does not fall. Therefore, the mowing work can be performed with peace of mind.

Further, by operating the switching lever 50, the pressing cam 52 can be easily rotated to loosen or stretch the belt 8. That is, the belt 8 can be loosened or stretched by directly operating the switching lever 50 by hand without using a tool. Further, since the pressing cam 52 is provided at the base end portion of the switching lever 50, the pressing cam 52 can be directly rotated by operating the switching lever 50 as compared with the configuration in which a link or the like is interposed. Further, since the fall prevention locking portion 54 is also provided at the base end portion of the switching lever 50, the fall prevention locking portion 54 can be moved to the locked plate 27 simply by moving the switching lever 50 to the cutting work position. It can be automatically positioned on the lower side.

On the other hand, the operation of the switching lever 50 can be performed only by removing the outer cover 61. Moreover, in order to remove the outer cover 61, it is necessary to loosen the screw 62 that attaches the outer cover 61, and a tool such as a driver is also required. That is, the work of removing the outer cover 61 is daringly more troublesome than the operation of the switching lever 50, and the work of removing the outer cover 61 is always required to operate the switching lever 50. By going through one step of removing the outer cover 61 in this way, careless operation of the switching lever 50 is prevented, and the switching operation of the switching lever 50 is assured, and as a result, the blade unit 7 is attached / detached. Increases work safety. Further, when the outer cover 61 is attached, the switching lever 50 is inoperably locked by the notch 63 of the outer cover 61, so that erroneous operation of the switching lever 50 can be reliably prevented, and the switching lever 50 can be reliably prevented. It is also possible to prevent the lever from rotating by itself due to vibration or contact with other objects. Since the lock portion for locking the switching lever 50 is provided on the outer cover 61 itself, it is not necessary to provide the lock portion separately from the outer cover 61, and the lock portion can be obtained only by removing the outer cover 61. The locked state can be released automatically.

In the present embodiment, the outer cover 61 partially covers the base end side of the switching lever 50, but even if the outer cover 61 covers the entire switching lever 50 as shown in FIG. good. In the configuration shown in FIG. 16, a locking protrusion 65 is formed on the inner surface of the side wall portion 61b of the outer cover 61, and the switching lever 50 is rotated from the cutting work position to the unit attachment / detachment position by the locking protrusion 65. Rotation is restricted so as not to. The locking protrusion 65 constitutes a locking portion that prevents the switching lever 50 from rotating to the unit attachment / detachment position, similarly to the upper portion of the notch portion 63 described above. In the form of FIG. 16, the locking protrusion 65 is formed on the inner surface of the side wall portion 61b of the outer cover 61, but the inner surface itself of the side wall portion 61b of the outer cover 61 is locked without forming the locking protrusion 65. May be. Further, the locking protrusion 65 may be projected onto the inner surface of the outer wall portion 61a of the outer cover 61, for example. Further, as shown in FIG. 17, the outer cover 61 may not cover the switching lever 50. As described above, the form of the outer cover 61 can be changed in various ways.

Further, the shape of the engaging pin 24 can be changed in various ways, and a straight pin configuration may be used instead of the stepped pin configuration as described above. Although the straight portion 24c is provided on the engaging shaft portion, the shape may not have the straight portion 24c, the entire engaging shaft portion may be composed of the tapered portion 24d, or along the axial direction. It may have a curved curved shape. Further, the cross section is not limited to a circular shape, and may be a rectangular cross section, and may have various protrusion shapes. Therefore, instead of the pair of front and rear engaging pins 24, for example, a pair of front and rear engaging projections made of sheet metal may be used. Further, although the separating direction of the pair of engaging pins 24 and the separating direction of the pair of engaging holes 39 are set to the front-rear direction, they are orthogonal to the straight line 38 connecting the center of the driving side pulley 31 and the center of the driven side pulley 13. The direction may be the direction inclined within a range not exceeding 45 degrees with respect to the direction orthogonal to the straight line 38 connecting the center of the driving side pulley 31 and the center of the driven side pulley 13. Further, the engaging pins 24 and the engaging holes 39 may be provided one by one instead of being provided one by one. However, if there is only one engaging pin 24 or the like, the blade unit 7 swings in an arbitrary direction. Therefore, a guide for restricting the swing of the blade unit 7 in a predetermined direction is provided to drive the drive side. It is preferable to regulate the swing of the blade unit 7 in the direction orthogonal to the straight line 38 connecting the center of the pulley 31 and the center of the driven pulley 13.

The blade unit 7 is provided with an engaging pin 24 and the main body 6 is provided with an engaging hole 39, but conversely, the blade unit 7 is provided with an engaging hole 39 and the main body 6 is provided with an engaging pin 24. May be good. Further, a pair of front and rear engaging holes 39 and a pair of front and rear engaging pins 24 are provided so that the blade unit 7 can swing mainly in the vertical direction. However, the pair of front and rear engaging holes 39 are connected to form one front and rear. A slit extending in the direction may be provided. When the slit is provided, a plate-shaped engaging portion that engages with the slit may be provided instead of the pair of front and rear engaging pins 24. For example, a part of the right side plate 15 of the blade unit 7 is bent to form a plate-shaped engaging portion, or a plate-shaped body for engagement is separately attached to the right side plate 15 and the plate-shaped body is transformed into a plate-shaped body. The engaging portion of the above may be formed.

Although the pressing cam 52 presses the blade unit 7 downward, the direction in which the pressing cam 52 presses the blade unit 7 can be changed in various ways. For example, the center of the drive side pulley 31 and the driven side pulley 13 can be changed. It may be in the direction of the straight line 38 connecting the center of the. The driven pulley 13 was located below the drive pulley 31, but it may be located at the rear, and the drive pulley 31 and the driven pulley 13 are arranged side by side at the same height. It may be.

Further, in the above embodiment, the blade unit 7 is configured to swing up and down with the right end as a fulcrum, but the configuration for moving the blade unit 7 is not limited to this, and various configurations may be used. For example, as shown in FIG. 18, the blade unit 7 may be configured to slide up and down. For example, a pair of front and rear support pins 70 are provided on the left and right side plates 14 and 15 of the blade unit 7, and a pair of front and rear guide holes 71 are formed on the left and right side plates 33 and 34 of the main body 6, respectively. The guide hole 71 is a long hole that is long in the vertical direction, and the front and rear support pins 70 are engaged with the front and rear guide holes 71, respectively. When the pressing cam 52 is in the pressing position for pushing the upper plate 16 of the blade unit 7 downward as shown in FIG. 18A, the blade unit 7 is pushed downward by the pressing cam 52 and slides, and the belt 8 It will be in a stretched state. When the pressing cam 52 is in the pressing release position separated upward from the upper plate 16 of the blade unit 7 as shown in FIG. 18B, the blade unit 7 slides upward due to the tension of the belt 8 and the belt 8 is loosened. It becomes a state.

Further, the blade unit 7 may be configured to rotate around the axis in the left-right direction. The rotation fulcrum of the blade unit 7 is arbitrary, but for example, in the embodiment shown in FIG. 19, the rotation fulcrum P is provided at the rear and lower parts of the blade unit 7. That is, the rotation fulcrum P of the blade unit 7 is on the rear side and the lower side of the center of the driven side pulley 13. When the pressing cam 52 is in the pressing position for pushing the upper plate 16 of the blade unit 7 downward as shown in FIG. 19A, the blade unit 7 is pushed downward by the pressing cam 52 to push the rotation fulcrum P. It rotates counterclockwise when viewed from the front as the center, the distance between the centers between the drive side pulley 31 and the driven side pulley 13 becomes relatively large, and the belt 8 is in a stretched state. When the pressing cam 52 is in the pressing release position separated upward from the upper plate 16 of the blade unit 7 as shown in FIG. 19B, the blade unit 7 is pulled upward by the tension of the belt 8 and the rotation fulcrum P The belt 8 rotates clockwise around the center, the distance between the centers of the drive side pulley 31 and the driven side pulley 13 becomes relatively short, and the belt 8 becomes loose.

As shown in FIG. 20, the rotation fulcrum P of the blade unit 7 may be provided at the front end portion. That is, the rotation fulcrum P is located on the front side of the center of the driven side pulley 13. When the pressing cam 52 is in the pressing position for pushing the upper plate 16 of the blade unit 7 downward as shown in FIG. 20A, the blade unit 7 is pushed downward by the pressing cam 52 to push the rotation fulcrum P. It rotates clockwise as the center, and the distance between the centers between the drive side pulley 31 and the driven side pulley 13 becomes relatively large, and the belt 8 is in a stretched state. When the pressing cam 52 is in the pressing release position retracted upward from the upper plate 16 of the blade unit 7 as shown in FIG. 20B, the blade unit 7 is pulled upward by the tension of the belt 8 and the rotation fulcrum P The belt 8 rotates counterclockwise when viewed from the front, and the distance between the centers of the drive side pulley 31 and the driven side pulley 13 becomes relatively short, and the belt 8 becomes loose.

21 and 22 show more specific rotation configurations of the blade unit 7 of FIG. 20. Support pins 70 are attached to the left and right side plates 14 and 15 of the blade unit 7, respectively, and the left and right support pins 70 are rotatably supported by the left and right side plates 33 and 34, respectively. Therefore, the left and right support pins 70 are rotation fulcrums P, and the blade unit 7 can rotate up and down with the left and right support pins 70 as fulcrums.

The support pin 70 projects outward from the side plates 14 and 15, and the protruding portion is composed of a large-diameter intermediate shaft portion 70a and a small-diameter support shaft portion 70b. As shown in FIG. 22A, the support shaft portion 70b of the right support pin 70 is inserted into the support hole 72 of the right side plate 34, and the support shaft portion 70b of the right support pin 70 is the right side plate. It is rotatably supported by the support hole 72 of 34. The intermediate shaft portion 70a of the right support pin 70 is located between the right side plate 15 and the right side plate 34, and the distance between the right side plate 15 and the right side plate 34 by the intermediate shaft portion 70a. Is kept.

As shown in FIGS. 21 and 22 (b), the left side plate 33 is formed with a notched recess 73 that opens downward. The support shaft portion 70b of the left support pin 70 is engaged from below in the notch recess 73, and the support shaft portion 70b of the left support pin 70 can be rotated into the notch recess 73 of the left side plate 33. It is supported. The intermediate shaft portion 70a of the left support pin 70 is located between the left side plate 14 and the left side plate 33. When the blade unit 7 is attached to the main body 6, the separation distance between the left side plate 14 and the left side plate 33 is longer than the length of the intermediate shaft portion 70a of the left support pin 70. Therefore, the blade unit 7 can be slid to the left until the intermediate shaft portion 70a of the support pin 70 on the left side comes into contact with the side plate 33 on the left side.

When removing the blade unit 7 from the main body 6, first, the blade unit 7 is slid to the left side, and the support shaft portion 70b of the support pin 70 on the right side is pulled out from the support hole 72 of the side plate 34 on the right side. After that, the blade unit 7 is moved downward, the support shaft portion 70b of the left support pin 70 is removed from the notch recess 73 of the left side plate 33, and the blade unit 7 is separated downward from the main body 6. .. When the blade unit 7 is attached to the main body 6, it can be attached by the reverse procedure.

Although the pressing cam 52 is provided as a pressing portion for pressing the blade unit 7, the pressing portion may have a configuration other than the cam. Similarly, the operation unit may have various forms. A link or the like may be interposed between the operation unit and the pressing unit. The lock portion may be provided on the outer cover 61 or may be provided separately from the outer cover 61. Although the belt 8 is used as the power transmission body, the power transmission body may be a chain, and the driving side rotating body and the driven side rotating body may be sprocket instead of the pulley.

1 Front wheel 2 Rear wheel 3 Handle 4 Grass collecting box 6 Main body 7 Blade unit 8 Belt (power transmitter)
10 Fixed blade 11 Rotary blade 12 Rotating shaft 13 Driven side pulley (driven side rotating body)
14 Left side plate 15 Right side plate 16 Top plate 17 Strut 18 Fixed blade holder 18a Arm 19 Adjusting bolt 20 Coil spring 21 Bearing 22 Bearing holder 23 Inner cover 24 Engagement pin (blade side engagement part)
24a Mounting shaft part 24b Intermediate shaft part 24c Straight part 24d Tapered part 25 Guided protrusion 26 on the front side Guided protrusion 27 Locked plate 27a End (locked part for fall prevention)
30 Motor 31 Drive side pulley (drive side rotating body)
32 Wheel link 33 Left side plate 34 Right side plate 35 Connecting member 36 Motor holder 37 Main shaft 38 Straight line 39 Engagement hole (main body side engagement part)
40 Front side guide protrusion 41 Rear side guide protrusion 42 Stopper 45 Notch 46 Straight part 47 Inclined part 48 Nut 49 Lever stopper 50 Switching lever (operation part)
51 Rotating shaft 52 Pressing cam (pressing part)
53 Cam member 54 Fall prevention locking part 55 Projection piece part 60 Housing body 61 Outer cover (cover)
61a Outer wall 61b Side wall 62 Screw 63 Notch (lock)
64 Step portion 65 Lock protrusion (lock portion)
70 Support pin 70a Intermediate shaft 70b Support shaft 71 Guide hole 72 Support hole 73 Notch recess P Rotation fulcrum

Claims (4)

A lawn mower with a blade unit attached to the main body so that it can be attached and detached.
The blade unit includes a rotating shaft extending in the horizontal direction, a blade that rotates integrally with the rotating shaft, and a driven side rotating wheel mounted on one end of the rotating shaft.
The main body includes a drive source for driving the blade and a drive side rotating wheel for transmitting the rotation of the drive source.
An endless power transmitter is wound between the driving side rotating wheel and the driven side rotating wheel.
The blade unit is configured to be movable with respect to the main body so that the distance between the centers between the driving side rotating wheel and the driven side rotating wheel changes.
The main body has a pressing portion that can move between a pressing position that presses the blade unit in a predetermined direction so that the distance between the centers becomes large, and a pressing release position that releases or reduces the pressing force, and the pressing portion. In order to move to the pressing position and the pressing release position, it is equipped with an operation unit that can switch between the cutting work position corresponding to the pressing position of the pressing unit and the unit attachment / detachment position corresponding to the pressing release position of the pressing unit.
When the operation unit is located at the cutting work position, the power transmission body is in a stretched state, and the blade unit is held in the predetermined cutting state by the balance between the pressing force of the pressing unit and the tension of the power transmission body.
A lawn mower characterized in that the power transmitter is in a loosened state when the operation unit is located at the unit attachment / detachment position. The lawn mower according to claim 1, further comprising a lock portion that prevents the operation unit located at the mowing work position from moving to the unit attachment / detachment position. It is equipped with a removable cover that covers the driving side rotating body, the driven side rotating body, and the power transmission body. With the cover attached, it is not possible to switch from the cutting work position of the operation unit to the unit attachment / detachment position. The lawn mower according to claim 1, wherein the operation of switching from the mowing work position of the operation unit to the unit attachment / detachment position can be performed by removing the mower. The lawn mower according to claim 3, wherein the cover is provided with a lock portion that prevents the operation unit located at the mowing work position from moving to the unit attachment / detachment position.

Images