Sheet lock structure and work machine equipped with a sheet lock structure

Abstract

To surely fix a driver seat to a machine body.SOLUTION: A seat lock structure where an operator seat 6 swingably arranged on a seat support part around a horizontal axis is fixed to the seat support part in a swinging regulation state comprises: a fixing pin 58 which is arranged on a bottom face of the operator seat 6 and movable between an advance position and an exit position; an engaging member 51 which is arranged on a top face of the seat support part and engaged with the fixing pin 58 at the advance position; and a pressing member 60 which presses the fixing pin 58 in a moving direction to the advance position. The engaging member 51 includes: an engagement hole 59 into which the fixing pin 58 at the advance position is inserted to regulate upper oscillation of the operator seat 6; and a slant guide face 74 which contacts with a tip part of the fixing pin 58 at the advance position when the operator seat 6 oscillates downward, and guides the tip part into the engagement hole 59 while moving the fixing pin 58 against the pressing power to the exit position in accompany with the downward oscillation of the operator seat 6. The tip part of the fixing pin 58 perform point contact or line contact with the guide face 74.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a seat lock structure for fixing a driver's seat in a state where swinging is restricted in a working machine such as a backhoe, and a working machine provided with the seat lock structure.

Background Art

[0002] Conventionally, a driver's seat for a working vehicle disclosed in Patent Document 1 is known. The driver's seat disclosed in Patent Document 1 is a working vehicle in which a seat support member is attached to be vertically swingable around a lateral axis near the front end, and the seat is attached to the seat support member, wherein a cam surface is formed on the distal end side of a locking member attached to the seat support member, and as the seat support member swings downward, the lock pin is pushed against the spring by the cam surface, and then the lock pin is fitted into the engagement hole of the locking member by the spring by arranging the cam surface relative to the lock pin so that the seat support member can be fixed in the seating seat support posture.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] When the seat lock structure is provided, a structure that can easily fix the driver's seat to the machine body is required. For example, the seat lock structure is preferably a structure in which the driver's seat is reliably fixed to the machine body by the self-weight of the driver's seat.

[0005] However, in the structure of the above Patent Document 1, since the specific structure of the contact portion between the lock pin and the cam surface is not considered, it is necessary to apply a large external force to swing the driver's seat downward to the position where the lock pin fits into the engagement hole of the locking member while the cam surface pushes the lock pin against the spring.

[0006] In view of the above-mentioned problems, the present invention aims to provide a seat lock structure and a work machine equipped with a seat lock structure that can easily fix the driver's seat to the machine body in a work machine in which the driver's seat is provided to be swingable. [Means for solving the problem]

[0007] The seat lock structure of the present invention is a seat lock structure for fixing a driver's seat, which is arranged to swing freely around a horizontal axis relative to a seat support, in a state in which the swinging relative to the seat support is restricted, comprising: a fixing pin disposed on the bottom surface of the driver's seat and moving between two points, an extended position and an extended position; an engaging member disposed on the upper surface of the seat support and engaging with the fixing pin at the extended position; and a biasing member that applies a biasing force to move the fixing pin in the direction of the extended position. A support plate positioned below the engagement member, The engaging member comprises an engaging hole into which the fixing pin is inserted when the fixing pin is in the extended position, thereby restricting upward swinging of the driver's seat; and an inclined guide surface that contacts the tip of the fixing pin in the extended position when the driver's seat is swung downward, and guides the tip of the fixing pin to the engaging hole while moving the fixing pin in the direction of the retracted position against the biasing force as the driver's seat swings downward, wherein the tip of the fixing pin makes point contact or line contact with the guide surface. The engaging member has a first plate portion extending upward from the upper surface of the support plate, and a second plate portion extending forward and downward from the upper end of the first plate portion and having the guide surface and the engaging hole. The first plate portion and the second plate portion are fixed to the upper surface of the support plate, and the first plate portion and the second plate portion are connected in a mountain-like manner with the upper end bent. The fixing pin engages with the engaging member when its tip passes through the guide surface of the second plate portion due to the downward swinging of the driver's seat, and when it comes into contact with the first plate portion, its vertical movement is restricted by the engaging hole and the support plate when inserted into the engaging hole of the second plate portion, and its backward movement is restricted when it comes into contact with the first plate portion. . [Effects of the Invention]

[0008] According to the above seat lock structure, the sliding resistance between the tip of the fixing pin and the guide surface can be reduced, making it easy to fix the driver's seat to the aircraft body. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall side view of the work machine. [Figure 2] This is an overall perspective view of the work machine, seen from the front right. [Figure 3] A plan view of the aircraft. [Figure 4]This is a perspective view of the aircraft and cockpit from the front right. [Figure 5] This is a perspective view of the hood and support frame from the front right. [Figure 6] This is a perspective view of the driver's seat and support frame from the front right. [Figure 7] This is a front view of the driver's seat and support frame, seen from the front. [Figure 8] This is a side view of the driver's seat and support frame, seen from the right. [Figure 9] This is an upward view of the fixing pin and intermediate support plate, seen from the lower right. [Figure 10] These are cross-sectional views of the fixing pin and intermediate support plate, cut along the vertical and front-to-back directions. [Figure 11] This is an overhead view of the top surface of the support frame, seen from the upper right. [Figure 12] (a) is a cross-sectional view showing that the tip of the fixing pin makes line contact with the guide surface, and (b) is a cross-sectional view showing that the tip of the fixing pin makes point contact with the guide surface. [Figure 13] (a) is a perspective view showing the anti-rotation mechanism, and (b) is a cross-sectional view showing the anti-rotation mechanism. [Figure 14] This is a right-side view showing the operation of releasing the seat lock mechanism and swinging the driver's seat relative to the hood. [Figure 15] This is a right-side view showing the operation to restrict the movement of the driver's seat relative to the hood in the seat lock mechanism. [Figure 16] This is a right-side view showing the operation to release the restriction on the driver's seat's movement relative to the hood in the seat lock mechanism. [Modes for carrying out the invention]

[0010] One embodiment of the present invention will be described below with reference to the drawings.

[0011] FIG. 1 is a side view showing the overall configuration of the work machine 1 according to the present embodiment. FIG. 2 is a perspective view showing the overall configuration of the work machine 1 according to the present embodiment. In the present embodiment, a backhoe which is a swing work machine is illustrated as the work machine 1. The work machine 1 is not limited to a backhoe, and may be another work machine such as a tractor.

[0012] As shown in FIG. 1 and FIG. 2, the work machine 1 includes a machine body (swivel base) 2, a traveling device 3, and a work device 4. The machine body 2 is mounted with a driver's seat 6 on which an operator sits, and a 4-post type ROPS 15. The ROPS 15 is of a canopy specification having a roof 19.

[0013] In the present embodiment, the direction facing forward of the operator seated in the driver's seat 6 of the work machine 1 (the direction of arrow A1 in FIG. 1) is defined as the front, the direction facing rearward of the operator (the direction of arrow A2 in FIG. 1) is defined as the rear, and the direction of arrow A3 in FIG. 1 is described as the front-rear direction. Further, the direction facing left of the operator (the near side in FIG. 1) is defined as the left, and the direction facing right of the operator (the far side in FIG. 1) is described as the right.

[0014] Further, a direction orthogonal to the front-rear direction A3 and extending horizontally is described as the machine body width direction.

[0015] At the rear part of the machine body 2, a bonnet 14 that covers mounted objects such as a prime mover (engine) is provided. At the lower part of the bonnet 14 in the rear part of the machine body 2, a weight 25 for achieving weight balance with the work device 4 is arranged. The work machine 1 of the present embodiment is a small backhoe, and the driver's seat 6 is arranged above the prime mover (prime mover chamber).

[0016] As shown in Figure 3, the prime mover 91 is mounted in the center of the width direction at the rear of the aircraft body 2. The prime mover 91 is located below the driver's seat 6. To the left of the prime mover 91 are a cooling fan 100, a radiator 92, and an oil cooler 93. To the right of the prime mover 91 is a hydraulic pump 95. The prime mover 91, cooling fan 100, radiator 92, oil cooler 93, and hydraulic pump 95 are housed in a prime mover compartment 91A located inside the bonnet 14.

[0017] The bonnet 14 is located at the rear of the aircraft body 2. Inside the bonnet 14 is a prime mover room 91A (see Figure 3) where the prime mover 91 and other components are stored. The bonnet 14 is formed in a box shape by combining plate members, which are first cover bodies 101A to fourth cover bodies 101D (see Figure 5). The bonnet 14 also has a bonnet support frame 98 inside that supports the first cover bodies 101A to fourth cover bodies 101D (see Figure 4).

[0018] As shown in Figures 4 and 5, the first cover body 101A covers the front and top of the prime mover 91. The first cover body 101A has a front wall 101Aa located in front of the prime mover 91 and an upper wall 101Ab located above the prime mover 91. An inspection opening 99 is formed in the upper wall 101Ab for inspecting the prime mover 91 housed in the bonnet 14.

[0019] As shown in Figure 3, the second cover body 101B is positioned behind the first cover body 101A and the prime mover 91. The third cover body 101C covers the prime mover 91, cooling fan 100, radiator 92, and oil cooler 93, etc. from the left. The fourth cover body 101D covers the prime mover 91 and hydraulic pump 95, etc. from the right.

[0020] Of the first to fourth cover bodies 101A to 101D, the second cover body 101B and a portion of the third cover body 101C are openable and closable. This allows the prime mover 91, radiator 92, oil cooler 93, and hydraulic pump 95 housed inside the prime mover room 91A to be accessed and maintained from the rear or left side.

[0021] As shown in Figure 4, a bonnet support frame 98 is arranged inside the bonnet 14 to support the first cover body 101A to the fourth cover body 101D.

[0022] The bonnet support frame 98 is formed in an upright shape extending upward from the pivot base plate 5 and has a skeletal structure made up of multiple rod-shaped frame members arranged vertically and horizontally. A floor section 21 is provided in front of the bonnet support frame 98. The bonnet support frame 98 has a lower frame 98B positioned below the floor section 21 and an upper frame 98T positioned above the floor section 21.

[0023] The lower frame 98B includes a first lower frame 98B1 located below the left front of the driver's seat 6, a second lower frame 98B2 located below the right front of the driver's seat 6, a third lower frame 98B3 located below the left rear of the driver's seat 6, and a fourth lower frame 98B4 located below the right rear of the driver's seat 6. The first to fourth lower frames 98B1 to 98B4 are all rod-shaped frames and are arranged to stand upright from the pivot base plate 5. The first to fourth lower frames 98B1 to 98B4 are arranged at a distance from each other in the front-rear or left-right direction.

[0024] The upper frame 98T is a rod-shaped member that is continuously positioned above the lower frame 98B. There are four upper frames 98T, just like the lower frame 98B. The four upper frames 98T are the first upper frame 98T1, the second upper frame 98T2, the third upper frame 98T3, and the fourth upper frame 98T4. The four upper frames 98T are positioned at a distance from each other in the front-to-back or left-to-right direction. The upper frames 98T and the lower frame 98B are provided at the four horizontal corners of the support frame 98 (front left, front right, rear left, and rear right corners).

[0025] The first upper frame 98T1 and the second upper frame 98T2 are arranged with a gap between them in the left-right direction. The first upper frame 98T1 and the second upper frame 98T2 extend in the vertical direction, are bent towards the rear at their upper ends, and are formed to extend horizontally along the front-rear direction to their rear ends (approximately L-shaped when viewed from the side).

[0026] A first connecting frame 102 is provided between the lower end of the first upper frame 98T1 and the lower end of the second upper frame 98T2, extending horizontally in the left-right direction. The first connecting frame 102 connects the lower end of the first upper frame 98T1 and the lower end of the second upper frame 98T2 in the left-right direction.

[0027] A second connecting frame 103, extending in the left-right direction, is provided between the rearward-bent portion (upper front end) of the first upper frame 98T1 and the rearward-bent portion (upper front end) of the second upper frame 98T2. The second connecting frame 103 connects the upper end of the first upper frame 98T1 and the upper end of the second upper frame 98T2 in the left-right direction.

[0028] A third connecting frame 104, extending in the left-right direction, is provided between the rear end (upper rear end) of the first upper frame 98T1 and the rear end (upper rear end) of the second upper frame 98T2. The third connecting frame 104 connects the rear end of the first upper frame 98T1 and the rear end of the second upper frame 98T2 in the left-right direction.

[0029] The bonnet support frame 98 is constructed by combining frame materials that extend vertically, horizontally, or in the front-to-back direction, creating a highly rigid three-dimensional lattice-like framework on top of the pivot base plate 5. The bonnet support frame 98 is formed above the driver's seat 6 via the bonnet 14. By supporting the driver's seat 6 on such a highly rigid bonnet support frame 98, the driver's seat 6 can be reliably and firmly supported above the pivot base plate 5.

[0030] As shown in Figures 4, 5, and 11, the upper wall (seat support portion) 101Ab of the first cover body 101A is positioned above the bonnet support frame 98. The upper wall 101Ab of the first cover body 101A is positioned below the seat lock structure 50, which will be described later, and supports the seat lock structure 50 from below. The upper wall 101Ab is positioned below the engaging member 51, which will be described later, and serves as a support plate 52 that supports the engaging member 51 from below. As shown in Figures 4 and 11, a rectangular opening 98H is formed at the top of the support frame 98 when viewed from above. This opening 98H is surrounded by four members: the first upper frame 98T1 (upper part of the first upper frame 98T1) which extends in the front-rear direction, the second upper frame 98T2 (upper part of the second upper frame 98T2) which extends in the front-rear direction, and the second connecting frame 103 and third connecting frame 104 which extend in the left-right direction. Above the opening 98H, a reinforcing frame 120 is positioned around the front wall 101Aa and upper wall 101Ab of the first cover body 101A. The upper wall 101Ab (support plate 52) is fixed to the reinforcing frame 120 by means of bolt fastening or other means.

[0031] The seat support portion is a member that supports the seat lock structure 50 against the aircraft body 2. In this embodiment, the seat lock structure 50 uses the upper wall 101Ab (support plate 52) of the first cover body 101A as the seat support portion. However, the seat support portion of the present invention is not limited to a plate member such as the support plate 52, nor is it limited to a member that constitutes the bonnet 14. For example, a member other than the bonnet 14 may be provided as the seat support portion, and the seat lock structure 50 may be supported against the aircraft body 2 using a different member. In this case, the seat support portion that supports the seat lock structure 50 does not have to be a plate member.

[0032] As shown in Figure 4, an inspection opening 99 is formed in the central right part of the upper wall 101Ab (support plate) for inspecting the interior (interior of the engine room 91A) surrounded by the bonnet support frame 98. The inspection opening 99 is closed by a cover member 106. The cover member 106 is detachably attached to the inspection opening 99 using fasteners 107 (three wing nuts in the illustrated example). Therefore, by removing the cover member 106, the interior of the engine room 91A can be inspected from the inspection opening 99.

[0033] An engaging member 51 of the sheet lock structure 50, which will be described later, is provided in the central left part of the upper wall 101Ab (support plate 52). The engaging member 51 is positioned to the left of the inspection opening 99, at a distance from the inspection opening 99 in the left-right direction.

[0034] Mounting members 53 are provided at the rear of the upper wall 101Ab to elastically support the driver's seat 6 (more precisely, the driver's seat 6 via the intermediate support plate 83). The mounting members 53 are made of an elastic material such as rubber. The mounting members 53 are formed in a short cylindrical shape with their axis oriented vertically. Mounting members 53 are provided on the left and right sides of the rear of the upper wall 101Ab, respectively.

[0035] Next, the driver's seat 6 and the intermediate support plate 83 that supports the driver's seat 6 from below will be described.

[0036] As shown in Figure 14, the driver's seat 6 is pivotable around a pivot shaft 54c located at the front of the driver's seat 6, and around the horizontal axis relative to the upper wall 101Ab of the support frame 98. By pivoting around the pivot shaft 54c, the rear of the driver's seat 6 moves away from or closer to the upper wall 101Ab. As shown in Figures 8 and 9, the intermediate support plate 83 is fixed to the bottom of the driver's seat 6 and pivots integrally with the driver's seat 6. The intermediate support plate 83 will be explained in more detail later. When the rear of the driver's seat 6 and the intermediate support plate 83 are pivoted relative to the support frame 98, the posture of the driver's seat 6 and the intermediate support plate 83 is changed.

[0037] Specifically, as can be seen from the change in posture from the left to the right diagram in Figure 14, the rear of the driver's seat 6 and the intermediate support plate 83 swing upward relative to the front. The driver's seat 6 can also change its posture as shown from the right to the left diagram in Figure 14. In other words, the driver's seat 6 can swing upward and downward.

[0038] In the following explanation, the posture shown in the left diagram of Figure 14 will be referred to as "horizontal posture H," and the posture shown in the right diagram of Figure 14 will be referred to as "folded-up posture S." Figures 4 to 10 illustrate the driver's seat 6 in "horizontal posture H," and when using Figures 4 to 10, the positions of the driver's seat 6 and the intermediate support plate 83 will be explained based on "horizontal posture H."

[0039] As shown in Figure 4, the driver's seat 6 is positioned above the inspection hatch 99. When the driver's seat 6 is in a horizontal position (seated position) H, the inspection hatch 99 is covered by the driver's seat 6, making it impossible to access the inspection hatch 99. When the position of the driver's seat 6 is changed from the horizontal position H to the upright position S, the inspection hatch 99 is no longer covered by the driver's seat 6 (exposed), making it possible to access the inspection hatch 99.

[0040] As shown in Figures 4, 6 to 8, the driver's seat 6 has a seat 6A and a backrest 6B. The seat 6A is the part where the operator sits (on which the buttocks and thighs rest). The backrest 6B is the part on which the seated operator leans their back. The backrest 6B is provided so as to extend upward or upward from the rear of the seat 6A. An angle adjustment lever 108 is provided on the right side of the backrest 6B, which allows adjustment of the tilt angle of the backrest 6B. A weight adjustment knob 109 is provided at the right end of the rear of the seat 6A. The weight adjustment knob 109 adjusts the rebound force of the spring inside the seat 6A. By rotating the weight adjustment knob 109, the seating comfort of the seat 6A is adjusted.

[0041] As shown in Figures 7 and 8, the intermediate support plate 83 is a plate member positioned below the seat portion 6A so as to be approximately parallel to the bottom surface 6C of the seat portion 6A. In the "horizontal position H", the front end of the intermediate support plate 83 is bent at approximately a right angle so as to hang downwards.

[0042] The intermediate support plate 83 has different functions at its upper and lower parts. The upper part of the intermediate support plate 83 has the function of sliding the driver's seat 6 in the front-rear direction relative to the intermediate support plate 83. To achieve this sliding function, a sliding mechanism 80 is provided at the upper part of the intermediate support plate 83. The lower surface of the intermediate support plate 83 has the function of swinging the intermediate support plate 83 and the driver's seat 6 located at the upper part of the intermediate support plate 83. To achieve this swinging function, a swinging mechanism 54 is provided at the lower part of the intermediate support plate 83.

[0043] As shown in Figures 7 and 8, the slide mechanism 80 supports the driver's seat 6 so that it can slide freely in the front-rear direction relative to the intermediate support plate 83. The slide mechanism 80 is positioned between the bottom surface 6C of the seat 6A and the intermediate support plate 83. The slide mechanism 80 includes a first slide mechanism 81 provided on the left side of the bottom surface 6C, which has a first slide rail 84, a first slider 85, and a first bearing 86, and a second slide mechanism 82 provided on the right side of the bottom surface 6C, which has a second slide rail 87, a second slider 88, and a second bearing 89.

[0044] The swing mechanism 54 shown in Figures 6 to 11 supports the intermediate support plate 83 and the driver's seat 6 supported by the intermediate support plate 83 so that they can swing freely around an axis oriented in the left-right direction. The swing mechanism 54 in this embodiment swings the rear of the driver's seat 6 around a pivot shaft 54c that extends in the left-right direction and is provided at the front of the driver's seat 6. As shown in Figures 9 and 11, the swing mechanism 54 has a base body 54a provided on the second connecting frame 103 of the support frame 98, a swinging body 54b provided on the lower surface of the intermediate support plate 83, and a pivot shaft 54c that connects the base body 54a and the swinging body 54b.

[0045] As shown in Figure 11, the base body 54a has a left base piece 54aL and a right base piece 54aR, which are provided at a distance from each other in the left-right direction at the midpoint of the second connecting frame 103. The left base piece 54aL and the right base piece 54aR are plate members that are approximately triangular in shape when viewed from the side. A left insertion hole 55L is formed in the center of the left base piece 54aL through which the support shaft 54c is inserted in the left-right direction. A right insertion hole 55R is formed in the center of the right base piece 54aR through which the support shaft 54c is inserted in the left-right direction.

[0046] The second connecting frame 103 has a curved cross-section that rises towards the front and upper when cut perpendicular to the left-right direction. The left base piece 54aL and the right base piece 54aR are both attached to the curved front (top) surface of the second connecting frame 103 so as to stand upright towards the front and upper.

[0047] As shown in Figure 9, the oscillating body 54b is provided along the downwardly curved portion at the front end of the intermediate support plate 83. The oscillating body 54b consists of a left oscillating piece 54bL provided on the left side of the front end of the intermediate support plate 83 and a right oscillating piece provided on the right side of the front end of the intermediate support plate 83. The left oscillating piece 54bL and the right oscillating piece 54bR are mounted so as to stand upright downwards from the lower surface of the intermediate support plate 83. The left oscillating piece 54bL and the right oscillating piece 54bR are provided so as to extend along the front-rear direction. Through holes 56 are formed in the center of the left oscillating piece 54bL and the right oscillating piece 54bR in a through-hole along the left-right direction. The support shaft 54c is inserted through the through holes 56.

[0048] The support shaft 54c is an axis that connects the left base piece 54aL and the right base piece 54aR of the base body 54a to the left oscillating piece 54bL and the right oscillating piece 54bR of the oscillating body 54b in the left-right direction. The right end of the support shaft 54c is provided with a head that is larger in diameter than the opening diameters of the left insertion hole 55L, the right insertion hole 55R, and the insertion hole 56. The left end of the support shaft 54c is provided with a retaining pin 57 that prevents the support shaft 54c from coming out of the left insertion hole 55L, the right insertion hole 55R, and the insertion hole 56.

[0049] The aforementioned swinging mechanism 54 supports a swinging body 54b, which is provided on the lower surface of the intermediate support plate 83, so that it can swing around a pivot shaft 54c that extends in the left-right direction relative to a base body 54a provided on the second connecting frame 103 of the bonnet support frame 98. As a result, the intermediate support plate 83 and the driver's seat 6 supported by the intermediate support plate 83 can swing vertically at their rear, around the front part where the pivot shaft 54c is provided.

[0050] As shown in Figures 8 and 10, a seat lock structure 50 is provided between the upper wall 101Ab of the bonnet support frame 98 and the intermediate support plate 83, which fixes the driver's seat 6 in a state where its swinging (upward swinging) relative to the bonnet 14 is restricted.

[0051] The seat lock structure 50 has a fixing pin 58 positioned on the bottom surface 6C of the driver's seat 6 and an engaging member 51 positioned on the upper surface (upper wall 101Ab) of the bonnet 14. The fixing pin 58 is movable between two points: an extended position P1 (see Figure 15(d)) and an extended position P2 (see Figure 16(b)). The engaging member 51 has an engaging hole 59 that engages with the fixing pin 58. When the fixing pin 58 is moved to the extended position P1 (see Figure 15(d)), the fixing pin 58 engages with the engaging hole 59 of the engaging member 51. On the other hand, when the fixing pin 58 is moved to the extended position P2 (see Figure 16(b)), it moves out of the engaging hole 59 of the engaging member 51, and the tip of the fixing pin 58 no longer engages with the engaging hole 59. In other words, as shown in Figures 15 and 16, by moving the tip of the fixing pin 58 between two points, the extended position P1 and the retracted position P2, the sheet lock structure 50 switches between an engaged state RS (see Figures 15 and 16) in which the fixing pin 58 engages with the engaging member 51, and an unengaged state US (see Figures 15 and 16) in which the fixing pin 58 does not engage with the engaging member 51.

[0052] The seat lock structure 50 includes a biasing member 60 that biases the fixing pin 58 in the direction (rearward) in which the fixing pin 58 moves to the extended position P1. As will be described later, in this embodiment, the biasing member 60 is a coil spring. The biasing member 60 maintains the seat lock structure 50 in the engaged state RS by biasing the fixing pin 58 toward the extended position P1. In other words, in order to disengage the seat lock structure 50 US, the fixing pin 58 must be moved to the retracted position P2 against the biasing force of the biasing member 60.

[0053] When the seat lock structure 50 is in the engaged state RS, the driver's seat 6 is fixed in a state where its swinging relative to the hood 14 is restricted. When the seat lock structure 50 is in the disengaged state US, the restriction on the driver's seat 6's swinging relative to the hood 14 is released, and it becomes possible for it to swing.

[0054] Next, the fixing pin 58, engaging member 51, and biasing member 60 provided in the sheet lock structure 50 will be described in detail.

[0055] As shown in Figures 9 and 10, the fixing pin 58 is a rod-shaped member extending in the front-rear direction and is attached to the left center of the lower surface of the intermediate support plate 83. The base end (front end) of the fixing pin 58 is bent upward below the front end of the intermediate support plate 83. The base end (front end) of the fixing pin 58, which is bent upward, extends to the upper front of the front end of the intermediate support plate 83. The base end (front end) of the fixing pin 58 is bent at a right angle in the horizontal direction (to the right in the illustrated example). The base end (front end) of the fixing pin 58, which is bent at a right angle, is connected to a release lever that moves the fixing pin 58 from the extended position P1 to the retracted position P2 by a pulling operation. It is designated as 61. The release lever 61 is the part that is gripped when pulling the fixing pin 58 forward in order to disengage the seat lock structure 50 from the engaged state to the disengaged state. By using a release lever 61 in which the base end of the fixing pin 58 is bent at a right angle, it becomes easier for the operator to grip the fixing pin 58, and the fixing pin 58 can be easily pulled between the extended position P1 and the retracted position P2.

[0056] The tip (rear end) of the fixing pin 58 extends to approximately the center of the intermediate support plate 83 in the front-rear direction. The tip (rear end) of the fixing pin 58 is shaped to taper towards the front (rear) to facilitate insertion into the engagement hole 59 of the engagement member 51. The tip (rear end) of the fixing pin 58 is chamfered or rounded, allowing for line contact or point contact with the guide surface 74 of the engagement member 51, which will be described later. The shape of the tip (rear end) of the fixing pin 58 will be described in detail later.

[0057] As shown in Figure 10, the intermediate portion of the fixing pin 58 in the front-rear direction is guided to move freely in the front-rear direction using a first front-rear guide portion 62 and a second front-rear guide portion 63 which are arranged at a distance from each other in the front-rear direction.

[0058] As shown in Figures 10 and 13, a notch 66 is formed in the front part of the intermediate support plate 83. The first front / rear guide portion 62 is a hole formed in the first guide piece 64 that hangs down from the rear opening edge of the notch 66. In the middle of the intermediate support plate 83 in the front-rear direction, an upper / lower through portion 67 is formed, which is an opening that penetrates the intermediate support plate 83 in the vertical direction. The second front / rear guide portion 63 is a hole formed in the second guide piece 65 that hangs down from the front opening edge of the upper / lower through portion 67. The middle part of the fixing pin 58 in the front-rear direction is inserted through the first front / rear guide portion 62 and the second front / rear guide portion 63.

[0059] Next, the notched portion 66 and the upper and lower through portions 67 will be described.

[0060] As shown in Figure 13, the notch 66 is formed by cutting out the front end of the downwardly bent intermediate support plate 83 in the vertical direction. The notch 66 also extends horizontally from the front end of the intermediate support plate 83 toward the rear. By providing such a notch 66, the front end of the downwardly bent intermediate support plate 83 is no longer in front of the base end (front end) of the fixing pin 58. Therefore, the base end (front end) of the fixing pin 58 can be extended further forward than the intermediate support plate 83 while avoiding interference with the front end of the downwardly bent intermediate support plate 83.

[0061] As shown in Figures 9, 10, and 13, a first guide piece 64 is formed on the rear edge of the notch 66 to guide the fixing pin 58 in the front-rear direction. The first guide piece 64 is a plate member that hangs down from the rear edge of the notch 66. A first front-rear guide portion 62 is formed in the center of the first guide piece 64 to guide the fixing pin 58 in the front-rear direction. The first front-rear guide portion 62 is drilled in the center of the first guide piece 64 (at the midpoint in the vertical and horizontal directions of the first guide piece 64) so ​​as to penetrate the first guide piece 64 in the front-rear direction. The first front-rear guide portion 62 in this embodiment has a circular opening. The opening diameter of the first front-rear guide portion 62 is formed to be larger than the outer diameter of the fixing pin 58, and guides the fixing pin 58 to move freely in the front-rear direction.

[0062] As shown in Figures 9, 10, and 13, the vertical penetration portion 67 is formed in the middle of the intermediate support plate 83 in the front-rear direction. The vertical penetration portion 67 is located behind the notch portion 66 in the intermediate support plate 83 and is formed in the middle of the intermediate support plate 83 in the front-rear direction, penetrating the intermediate support plate 83 in the vertical direction. In this embodiment, the opening width of the vertical penetration portion 67 in the front-rear direction and the left-right direction is formed to be larger than the dimensions (outer dimensions) of the engaging member 51 in the front-rear direction and the left-right direction, allowing the upper end of the engaging member 51 to be guided (exposed) from below to above the intermediate support plate 83. In other words, the upper end of the engaging member 51 that engages with the fixing pin 58 can be exposed above the intermediate support plate 83 through the vertical penetration portion 67.

[0063] As shown in Figures 9 and 10, a second guide piece 65 is formed on the front edge of the upper and lower through portion 67 to guide the fixing pin 58 in the front-rear direction. The second guide piece 65 is a plate member that hangs down from the front edge of the upper and lower through portion 67. The fixing pin 58 is guided in the front-rear direction at the center of the second guide piece 65 (the midpoint in the vertical direction and the midpoint in the horizontal direction of the second guide piece 65). A second front and rear guide section 63 is formed.

[0064] The second front and rear guide portion 63 is formed by drilling a hole in the center of the second guide piece 65 so as to penetrate the second guide piece 65 in the front and rear direction. The second front and rear guide portion 63 in this embodiment has a circular opening. The opening diameter of the second front and rear guide portion 63 is formed to be larger than the outer diameter of the fixing pin 58, allowing the fixing pin 58 to be freely guided in the front and rear direction.

[0065] The fixing pin 58 is inserted through both the first front / rear guide section 62 and the second front / rear guide section 63, which are spaced apart in the front-rear direction, thereby being guided linearly and without wobble along the front-rear direction.

[0066] As shown in Figures 10 and 13, the aforementioned fixing pin 58 is provided with a rotation prevention mechanism 68 that prevents the release lever 61 from rotating around the axis of the fixing pin 58 when the release lever 61 is pulled.

[0067] When the release lever 61 rotates around the axis of the fixing pin 58, the part that rotates together with the fixing pin 58 may rub against other components such as the intermediate support plate 83, potentially causing paint peeling and damaging the appearance. The rotation prevention mechanism 68 has a function to prevent this problem from occurring.

[0068] The anti-rotation mechanism 68 includes a rotating plate 69 that is fixed to the release lever 61 and rotates integrally with the release lever 61. The rotating plate 69 is attached to a fixing pin 58 located behind the release lever 61.

[0069] The rotating plate 69 is a plate member attached to a fixing pin 58 at the rear of the release lever 61. The rotating plate 69 is fixed to the fixing pin 58 and can rotate integrally with the fixing pin 58. The rotating plate 69 has a first portion 69a extending upward from below the notch 66, and a second portion 69b extending rearward from the upper end of the first portion 69a.

[0070] The first part 69a is a plate member positioned intersecting the fixing pin 58, which extends in the front-rear direction, in the vertical direction. The first part 69a is fixed to the fixing pin 58 by welding or the like, and is rotatable together with the fixing pin 58.

[0071] The second part 69b is a plate member extending in the front-rear direction, and is provided so that its plate surface faces both upward and downward. The front end of the second part 69b is connected to the upper end of the first part 69a, and when the first part 69a rotates, the second part 69b can also rotate together with the first part 69a around the axis of the fixing pin 58. The lower surface 70 of the second part 69b is in surface contact with the upper surface 83a of the intermediate support plate 83.

[0072] The upper surface 83a of the intermediate support plate 83, which is in surface contact with the lower surface 70 of the second part 69b, is a rotation restricting part that restricts the rotation of the rotating plate 69 (second part 69b) by making surface contact with it.

[0073] Furthermore, it is preferable that the lower surface 70 of the second part 69b and the upper surface 83a of the intermediate support plate 83 are in surface contact at a position that overlaps with the driver's seat 6 in the vertical direction. Surface contact at a position that overlaps with the driver's seat 6 in the vertical direction makes it difficult to see from the outside the contact points where scratches and other marks are likely to appear (the contact points between the rotating plate 69 and the intermediate support plate 83). As a result, scratches and other marks become less noticeable, and the appearance around the driver's seat 6 can be improved.

[0074] As shown in Figure 11, the engaging member 51 is formed to protrude upward from the upper surface of the upper wall 101Ab (support plate) of the first cover body 101A. The engaging member 51 has a first plate portion 71 extending upward from the upper surface of the upper wall 101Ab (support plate), and a second plate portion 72 extending inclined downward and forward from the upper end of the first plate portion 71. In other words, the engaging member 51 has a first plate portion 71 and a second plate portion 72 that are connected in a bent (mountain-like) state at their upper ends. That is, the engaging member 51 is a substantially inverted V-shaped member. The connecting portion between the first plate portion 71 and the second plate portion 72 is formed in a curved shape.

[0075] As shown in Figure 10, the angle α of the second plate portion 72 with respect to the upper surface of the upper wall 101Ab (support plate) is greater than the angle β of the first plate portion 71 with respect to the upper surface of the upper wall 101Ab (support plate). Specifically, angle α is an obtuse angle, and angle β is a right angle or nearly a right angle. Angle α can be set, for example, between 100° and 130°.

[0076] The engaging member 51 is fixed to the upper surface of the upper wall 101Ab (support plate). For details, see Section 1. The first plate portion 71 and the second plate portion 72 are fixed to the upper surface of the upper wall 101Ab (support plate). In this way, by fixing both the first plate portion 71 and the second plate portion 72 to the upper surface of the upper wall 101Ab (support plate), both ends of the substantially inverted V-shaped engaging member 51 are fixed to the upper surface of the upper wall 101Ab (support plate). This improves the rigidity of the engaging member 51 and prevents the engaging member 51 from deforming when the fixing pin 58 contacts it.

[0077] The first plate portion 71 of the engaging member 51 is capable of restricting the movement of the fixing pin 58 backward. In contrast, the second plate portion 72 of the engaging member 51 has an engagement hole 59 that allows the tip of the fixing pin 58 to be inserted in the front-rear direction. In other words, the tip of the fixing pin 58 passes through the engagement hole 59 of the second plate portion 72 and engages with the engaging member 51 while in contact with the first plate portion 71. As a result, the fixing pin 58 is inserted through the engagement hole 59 of the second plate portion 72, restricting its movement in the vertical direction. Furthermore, the fixing pin 58 is restricted from moving backward by contacting the first plate portion 71.

[0078] The fixing pin 58 engages with the engaging member 51 when its tip is inserted into the engaging hole 59. When the fixing pin 58 is engaged with the engaging member 51, upward swinging of the driver's seat 6 is restricted. In other words, the engaging member 51 has an engaging hole 59 that restricts upward swinging of the driver's seat 6 by engaging with the tip of the fixing pin 58. In addition, the engaging member 51 restricts the fixing pin 58 from moving behind the position where the engaging member 51 is installed. In other words, the engaging member 51 positions the rear end of the fixing pin 58 at the installation position of the engaging member 51.

[0079] As shown in Figure 11, the second plate portion 72 in this embodiment is a plate member that branches into two towards the tip (lower end). In other words, the second plate portion 72 has a U-shaped notch that extends upward from the tip (lower end). When the tip (lower end) of the second plate portion 72 is fixed to the upper surface of the upper wall 101Ab (support plate), this notch becomes an engagement hole 59. In other words, by forming such a notch in the second plate portion 72, an engagement hole 59 into which the tip of the fixing pin 58 can be inserted can be easily formed between the second plate portion 72 and the upper surface of the upper wall 101Ab simply by folding the second plate portion 72 downward relative to the first plate portion 71 and fixing the engaging member 51 to the upper surface of the upper wall 101Ab.

[0080] As shown in Figure 10, the biasing member 60 is an elastic member attached to the middle of the fixing pin 58 in the front-rear direction. In this embodiment, a spring member (coil spring) is used for the biasing member 60. The biasing member 60 is arranged to be expandable and contractible in the front-rear direction.

[0081] The rear end of the biasing member 60 is fixed to a spring attachment 73 which is attached to the fixing pin 58. The spring attachment 73 is attached to the fixing pin 58 midway in the front-rear direction. As a result, the rear end of the biasing member 60 is fixed to the fixing pin 58 midway in the front-rear direction.

[0082] The front end of the biasing member 60 is fixed to a first guide piece 64 that hangs down from the intermediate support plate 83. This allows the biasing member 60 to generate a biasing force in the front-rear direction while sandwiched between the fixing pin 58 and the first guide piece 64 (intermediate support plate 83). Since the position of the first guide piece 64 is fixed, the biasing force of the biasing member 60 acts as a force that moves the fixing pin 58 backward.

[0083] As shown in Figure 10, the biasing member 60 has a neutral position where no biasing force is generated in either the forward or backward direction. In other words, the coil spring constituting the biasing member 60 is in its natural length state, not expanded or contracted, as shown in Figure 9. The neutral position of the biasing member 60 in this embodiment is the position where the tip of the fixing pin 58 is inserted into the engagement hole 59 of the engaging member 51 (the position of engagement state RS). Now, consider the case where the fixing pin 58 is pulled forward from the state where the tip of the fixing pin 58 is engaged with the engagement hole 59 (engagement state RS). In this case, the position of the fixing pin 58 shifts forward of the neutral position, so the coil spring constituting the biasing member 60 shortens from its natural length, generating a biasing force on the fixing pin 58 in the direction of restoring it backward (advancing direction). In other words, the biasing member 60 applies a biasing force to the fixing pin 58 in the direction of restoring it to the engagement state RS. As a result, when the driver's seat 6 is not swinging upward, the fixing pin 58 will be in a neutral position where its tip is inserted into the engagement hole 59 of the engagement member 51, unless an external force (pulling force by the operator) is applied.

[0084] As shown in Figure 10, the second plate portion 72 of the engaging member 51 has a guide surface 74 that moves the fixing pin 58 toward the retracted position P2 against a biasing force acting in the direction that restores the fixing pin 58 to the engaged state RS. In this embodiment, the guide surface 74 is formed above the engaging hole 59 in the second plate portion 72 and is in the shape of an inclined surface that slopes toward the rear and upward. The tip of the fixing pin 58 makes point contact or line contact with the guide surface 74.

[0085] Figure 12 shows specific examples of the tip of the fixing pin 58 making point contact or line contact with the guide surface 74. Figure 12(a) shows an example where the tip of the fixing pin 58 makes line contact with the guide surface 74. Figure 12(b) shows an example where the tip of the fixing pin 58 makes point contact with the guide surface 74.

[0086] As shown in Figure 12(a), the guide surface 74 of the engaging member 51 is formed as a flat surface inclined toward the rear and upward. The inclination angle of the guide surface 74 with respect to the upper surface (upper wall 101Ab) of the seat support is θ1. The relationship between angle θ1 and the angle α described above is θ1 = 180 - α.

[0087] The tip of the fixing pin 58 has a chamfered portion 75. The chamfered portion 75 is formed by cutting the tip of the fixing pin 58. Depending on the shape along which the tip of the fixing pin 58 is cut, the chamfered portion 75 can take on multiple forms.

[0088] The chamfered portion 75 shown in Figure 12(a) is formed by cutting the lower part of the tip of the fixing pin 58 into a flat shape. In other words, the tip of the fixing pin 58 in Figure 12(a) has a flat chamfered portion 75. The flat chamfered portion 75 in Figure 12(a) is formed by cutting only the lower part of the tip into a flat shape, but a tapered chamfered portion 75 may also be formed by cutting the tip into a conical or frustoconical shape.

[0089] As shown in Figure 12(a), the planar chamfered portion 75 has an inclination angle (θ2) with respect to the upper surface of the seat support portion (upper wall 101Ab) when viewed along the axis of the fixing pin 58. Although not shown in Figure 12(a), the tapered chamfered portion 75 also has the same inclination angle (θ2) at the lower part of its tip. The inclination angle (θ2) of the planar or tapered chamfered portion 75 changes with the movement of the driver's seat 6. In other words, when the driver's seat 6 moves, the inclination angle of the fixing pin 58 changes. When the inclination angle of the fixing pin 58 changes, the inclination angle (θ2) of the chamfered portion 75 formed on the fixing pin 58 also changes with respect to the upper surface of the seat support portion (upper wall 101Ab).

[0090] In the cross-sectional view of Figure 12(a), the tip of the chamfered portion 75 contacts the second plate portion 72 of the engaging member 51 at a single point on the surface of the upper part of the guide surface 74. When the driver's seat 6 swings from the "folded-up position S" to the "horizontal position H", the inclination angle (θ2) with respect to the upper surface (upper wall 101Ab) of the seat support portion, when viewed along the axis of the fixing pin 58, changes in the direction of decreasing inclination. Simultaneously with the change in inclination angle (θ2), the position of the tip of the chamfered portion 75 moves forward, and the tip of the chamfered portion 75 moves as if sliding from the upper part to the lower part of the guide surface 74. As shown in Figure 12(a), when the tip of the chamfered portion 75 is located on the upper part of the guide surface 74, the inclination angle (θ2) is clearly smaller than the inclination angle (θ1). Due to the oscillation of the driver's seat 6, the inclination angle (θ2) becomes even smaller than the inclination angle (θ1). Therefore, within the range in which the tip of the chamfered portion 75 slides from the top to the bottom of the guide surface 74 (the oscillation range of the fixing pin 58), the inclination angle (θ2) will never coincide with the inclination angle (θ1).

[0091] Taking Figure 12(a) as a specific example, the inclination angle (θ1) is 45°, and (before the fixing pin 58 starts to swing) the inclination angle (θ2) is smaller than 45°. When the fixing pin 58 swings, the inclination angle (θ2) changes to an even smaller angle than the angle in Figure 12(a). As long as the tip of the chamfered portion 75 is in contact with the guide surface 74, the inclination angle (θ2) will never become 0°. In other words, the inclination angle (θ2) changes within the range of 10° < θ2 < 45° within the swing range in which the tip of the fixing pin 58 and the guide surface 74 are in contact, and the relationship (θ1) ≠ (θ2) always holds true.

[0092] By forming the chamfered portion 75 at an inclination angle (θ2) such that the relationship "(θ1)≠(θ2)" holds between it and the inclination angle (θ1), the tip of the chamfered portion 75 will continue to contact the guide surface 74 even when the driver's seat 6 swings. Note that the flat chamfered portion 75 is in contact with the guide surface 74. In the cross-sectional view of Figure 12(a) showing the state, it appears that the chamfered portion 75 is in contact with the guide surface 74 at a single point on the surface. However, in reality, there are continuous contact points in the left-right direction of the cross-section, so the guide surface 74 and the chamfered portion 75 are in line contact with each other. This can be easily understood by considering that the guide surface 74 and the chamfered portion 75 are planes with different inclination angles in contact with each other.

[0093] Furthermore, if we consider the cross-sectional view in Figure 12(a) to show the state in which the tapered chamfered portion 75 is in contact with the guide surface 74, then since the contact between the guide surface 74 and the chamfered portion 75 is between a curved surface and a flat surface, the guide surface 74 and the chamfered portion 75 make point contact. In this case, Figure 12(a) can be considered a cross-sectional view taken along the cutting plane passing through the point of contact between the guide surface 74 and the chamfered portion 75.

[0094] As shown in Figure 12(b), the guide surface 74 of the engaging member 51 is formed as a flat surface inclined toward the rear and upward, similar to the case in Figure 12(a). The difference between Figure 12(b) and Figure 12(a) is that the tip of the fixing pin 58 has a curved chamfered portion 75. In other words, in the case of Figure 12(b), the tip of the fixing pin 58 is rounded, and the tip of the fixing pin 58 is formed in a hemispherical shape. Note that the curved surface of the chamfered portion 75 also includes a curved surface that is approximately frustoconical or approximately conical.

[0095] Such a curved chamfered portion 75 makes point contact with the planar guide surface 74 at a portion of its curved surface (a portion of the chamfered portion 75). Which part of the chamfered portion 75 contacts the guide surface 74 depends on the curvature of the chamfered portion 75, the inclination angle (θ1) of the guide surface 74, etc. At a point on the curved surface of the chamfered portion 75 where the angle of the tangent coincides with the inclination angle (θ1) of the guide surface 74, the curved chamfered portion 75 makes point contact with the planar guide surface 74.

[0096] As shown in Figures 12(a) and 12(b), when the tip of the fixing pin 58 makes point contact or line contact with the guide surface 74, the contact area is smaller compared to when the tip of the fixing pin 58 and the guide surface 74 make surface contact. As a result, the frictional force generated between the chamfered portion 75 and the guide surface 74 can be reduced, and the fixing pin 58 can move along the inclined guide surface 74 without hindrance. In other words, when attempting to move the tip of the fixing pin 58 along the guide surface 74, the movement is not hindered by the frictional force between the fixing pin 58 and the guide surface 74. This makes it easier for the fixing pin 58 to be pushed back in the exit direction by the guide surface 74. Therefore, the weight of the driver's seat 6 can be used to reliably fix the driver's seat 6 to the machine body (bonnet 14) by changing the seat lock structure 50 from the unengaged state US to the engaged state RS.

[0097] Next, the procedure for fixing the driver's seat 6 to the upper surface of the hood 14 using the seat lock structure 50 of this embodiment (in other words, the method for fixing the driver's seat 6 using the seat lock structure 50), and the procedure for releasing the driver's seat 6 (in other words, the method for releasing the driver's seat 6 using the seat lock structure 50) will be described.

[0098] In Figure 15(a), the seat lock structure 50 is in the disengaged state US. As shown in Figure 15(a), when the driver's seat 6 is fixed to the upper surface of the bonnet 14 using the seat lock structure 50 of this embodiment, the intermediate support plate 83 and the rear of the driver's seat 6 provided on the upper surface of the intermediate support plate 83 are swung downward. This swinging may be performed by the weight of the driver's seat 6 itself, or by adding a downward force applied by the operator in addition to its own weight. A pivot shaft 54c is provided at the front of the driver's seat 6, and the rear of the driver's seat 6 swings downward around the pivot shaft 54c which is oriented in the left-right direction.

[0099] When the rear of the intermediate support plate 83 is swung downward around the support shaft 54c, the tip of the fixing pin 58 comes into contact with the upper part of the guide surface 74 of the engaging member 51. When the tip of the fixing pin 58 makes point contact with the guide surface 74, the frictional force generated between the tip of the fixing pin 58 and the guide surface 74 is smaller than in the case of surface contact. Therefore, the tip of the fixing pin 58 easily slides forward and downward along the inclined guide surface 74, and the fixing pin 58 moves forward against the biasing force of the biasing member 60.

[0100] Furthermore, if the tip of the fixing pin 58 is chamfered and the inclination angle (θ2) of the chamfered portion 75 and the inclination angle (θ1) of the guide surface 74 are different, then the chamfered portion 75 and the guide surface 74 will be in line contact. Even in the case of line contact, the frictional force generated between the tip of the fixing pin 58 and the guide surface 74 will be smaller than in the case of surface contact. Therefore, the tip of the fixing pin 58 is inclined against the guide surface 74 The fixing pin 58 slides easily forward and downward along the curve, and moves forward against the biasing force of the biasing member 60.

[0101] As shown in Figure 15(b), when the tip of the fixing pin 58 slides to the lower end of the inclined guide surface 74, and the fixing pin 58 moves forward as it slides, the biasing member 60 is in its shortest state, and therefore the greatest biasing force is generated in the biasing member 60.

[0102] As shown in Figure 15(c), when the tip of the fixing pin 58 slides below the inclined guide surface 74, the guide surface 74 that would move the fixing pin 58 forward disappears. In other words, the tip of the fixing pin 58 reaches the engagement hole 59. Therefore, the biasing force generated in the biasing member 60 switches the direction of movement of the fixing pin 58. As a result, the fixing pin 58 moves from the exit position P2 to the advance position P1 through the engagement hole 59.

[0103] As shown in Figure 15(d), the tip of the fixing pin 58, which has moved to the extended position P1, is inserted into the engagement hole 59, and the fixing pin 58 engages with the engagement hole 59 of the engagement member 51. As a result, the intermediate support plate 83 on which the fixing pin 58 is provided, and the driver's seat 6 supported by the intermediate support plate 83 are fixed to the upper wall 101Ab on which the engagement member 51 is provided. In this way, the seat lock structure 50 switches from the unengaged state US to the engaged state RS.

[0104] In Figure 16(a), the seat lock structure 50 is in the engaged state RS, and the position of the fixing pin 58 is slightly forward from the extended position P1. As shown in Figure 16(a), when releasing the driver's seat 6 using the seat lock structure 50 of this embodiment, from the state shown in Figure 15(d), the operator pulls the release lever 61 forward, and this pulling operation of the release lever 61 moves the fixing pin 58 connected to the release lever 61 from the extended position P1 to the retracted position P2.

[0105] As shown in Figure 16(b), when the fixing pin 58 moves to the exit position P2, the tip of the fixing pin 58 comes out of the engagement hole 59. This releases the fixing of the driver's seat 6.

[0106] As shown in Figure 16(c), when the rear of the driver's seat 6 and intermediate support plate 83 are swung upward with the tip of the fixing pin 58 protruding outside the engagement hole 59, the tip of the fixing pin 58 that has protruded outside the engagement hole 59 contacts the guide surface 74 adjacent to the top of the engagement hole 59. The guide surface 74 is inclined toward the rear and upward, and the tip of the fixing pin 58 makes point contact or line contact with the guide surface 74. Therefore, due to the biasing force of the biasing member 60, the tip of the fixing pin 58 moves on the guide surface 74 along the direction of the inclination of the guide surface 74 (towards the rear and upward).

[0107] As shown in Figure 16(d), when the rear of the driver's seat 6 is swung further upward from a state in which the tip of the fixing pin 58 is positioned above the guide surface 74, the fixing pin 58 moves backward until the biasing member 60 returns to its natural length. In this way, the seat lock structure 50 switches from the engaged state RS to the disengaged state US.

[0108] The seat lock structure 50 of the present invention is a seat lock structure 50 that fixes a driver's seat 6, which is arranged to swing freely around a horizontal axis relative to a seat support (upper wall 101Ab), in a state in which the swinging relative to the seat support is restricted, and comprises a fixing pin 58 disposed on the bottom surface 6C of the driver's seat 6 and moving between two points, an extended position P1 and an extended position P2, an engaging member 51 disposed on the upper surface of the seat support and engaging with the fixing pin 58 at the extended position P1, and a biasing force that biases the fixing pin 58 in the direction of moving to the extended position P1. The engaging member 51 comprises a biasing member 60 and an engaging member 51, which has an engaging hole 59 into which the fixing pin 58 is inserted when the fixing pin 58 is in the extended position P1, thereby restricting the upward swing of the driver's seat 6, and an inclined guide surface 74 that contacts the tip of the fixing pin 58 when the driver's seat 6 is swung downward and moves the fixing pin 58 toward the retracted position P2 against the biasing force as the driver's seat 6 swings downward, guiding the tip of the fixing pin 58 to the engaging hole 59, with the tip of the fixing pin 58 making point contact or line contact with the guide surface 74.

[0109] According to the above configuration, the tip of the fixing pin 58 is in point or line contact with the guide surface 74, so the frictional force generated between the tip and the guide surface 74 is small. Therefore, the tip of the fixing pin 58 that is in contact with the guide surface 74 moves easily along the guide surface 74 and is guided to the engagement hole 59. For this reason, the seat lock structure 50 of the present invention makes it possible to easily fix the driver's seat 6 to the machine body 2. In addition, the engagement member 51 is provided on the seat support side, and Since the fixed pin 58 is provided on the driver's seat 6 side, deformation of the engaging member 51 due to contact with other members can be suppressed compared to the case where the engaging member 51 is provided on the driver's seat 6 side.

[0110] The sheet lock structure 50 includes a support plate (upper wall 101Ab) positioned below the engaging member 51. The engaging member 51 has a first plate portion 71 extending upward from the upper surface of the support plate, and a second plate portion 72 extending forward and downward from the upper end of the first plate portion 71 and having a guide surface 74 and an engaging hole 59. The first plate portion 71 and the second plate portion 72 are fixed to the upper surface of the support plate.

[0111] According to this, by fixing both the first plate portion 71 and the second plate portion 72 to the upper surface of the support plate (upper wall 101Ab), the rigidity of the engaging member 51 is improved, and deformation of the engaging member 51 can be prevented when the fixing pin 58 contacts the engaging member 51.

[0112] Furthermore, of the two members provided on the engaging member 51, the second plate portion 72 is located in front of the first plate portion 71 (closer to the exit position P2). Therefore, when the fixing pin 58 is moved horizontally toward the advance position P1 (rearward), the tip of the fixing pin 58 is first inserted into the engagement hole 59 of the second plate portion 72. When the fixing pin 58 is moved further rearward, the tip of the fixing pin 58 comes into contact with the first plate portion 71. The first plate portion 71 does not have an engagement hole 59 like the second plate portion 72, and the forward movement of the fixing pin 58 is restricted by the first plate portion 71. In other words, the engaging member 51 described above has both the function of fixing the fixing pin 58 to the upper wall 101Ab (upper surface of the support plate) so as not to swing up and down by engaging with the engagement hole 59, and the function of restricting the forward movement of the fixing pin 58 by contacting the first plate portion 71 (the function of positioning the tip of the fixing pin 58 in a position to contact the first plate portion 71).

[0113] The tip of the fixing pin 58 has a flat or tapered chamfered portion 75, and the inclination angle (θ1) of the guide surface 74 with respect to the upper surface of the seat support (upper wall 101Ab) and the inclination angle (θ2) of the chamfered portion 75 with respect to the upper surface of the seat support when viewed along the horizontal axis are different from each other within the range of oscillation in which the tip of the fixing pin 58 and the guide surface 74 come into contact as the driver's seat 6 swings, and the tip of the chamfered portion 75 comes into contact with the guide surface 74.

[0114] According to this, the contact surface 75 provided at the tip of the fixing pin 58 makes line or point contact with the guide surface 74 of the engaging member 51, resulting in less friction compared to when surfaces are in contact with each other. This makes it easier for the tip of the fixing pin 58 to move along the guide surface 74. As a result, when the tip of the fixing pin 58 contacts the guide surface 74, it becomes easy to move the fixing pin 58 to the extended position P1, and the engagement of the sheet lock structure 50 can be performed smoothly and easily.

[0115] The tip of the fixing pin 58 has a curved chamfered portion, and a part of the chamfered portion may be in point contact with the guide surface 74.

[0116] According to this, the tip of the curved fixing pin 58 makes point contact with the guide surface 74 of the engaging member 51. Such point contact results in even less friction than surface-to-surface contact or line contact. As a result, the tip of the fixing pin 58 can easily move along the guide surface 74. Consequently, when the tip of the fixing pin 58 contacts the guide surface 74, it becomes easy to move the fixing pin 58 to the extended position P1, allowing the sheet lock structure 50 to engage smoothly and easily.

[0117] The seat lock structure 50 includes a release lever 61 connected to a fixing pin 58, which moves the fixing pin 58 from an extended position P1 to an extended position P2 by a pulling operation, and a rotation prevention mechanism 68 that prevents the release lever 61 from rotating around the axis of the fixing pin 58 during the pulling operation.

[0118] According to this, the operator can move the fixing pin 58 from the extended position P1 to the retracted position P2 against the biasing force of the biasing member 60 by grasping and pulling the release lever 61. In addition, when the release lever 61 is grasped, it is prevented from rotating around the axis of the fixing pin 58. If the release lever 61 rotates around the axis of the fixing pin 58, the part that rotates together with the fixing pin 58 may rub against other members such as the intermediate support plate 83, potentially causing paint peeling and damaging the appearance. However, the rotation prevention mechanism 68 prevents this problem from occurring.

[0119] The rotation prevention mechanism 68 includes a rotating plate 69 fixed to the engagement release lever 61 and rotating integrally with the engagement release lever 61, and a rotation restricting part that restricts the rotation of the rotating plate 69 by making surface contact with the rotating plate 69.

[0120] By employing such a rotation prevention mechanism 68, the rotating plate 69, which is fixed to the release lever 61 and rotates integrally with the release lever 61, makes surface contact with the rotation restricting part, thereby reliably restricting the rotation of the rotating plate 69. In other words, by using the rotation prevention mechanism 68 described above, the rotation of the release lever 61 can be suppressed simply and reliably.

[0121] Below the driver's seat 6, an intermediate support plate 83 is positioned at a distance below the bottom surface of the driver's seat 6, and a rotation restricting portion is formed on the intermediate support plate 83.

[0122] According to this, by bringing the upper surface 83a of the intermediate support plate into surface contact with the lower surface 70 of the second part 69b, the rotation of the rotating plate 69 and the engagement release lever 61 can be suppressed more easily and reliably.

[0123] The upper end of the rotating plate 69 protrudes above the intermediate support plate 83, and the rotation restricting portion is composed of a notch 66 cut out from the front end of the intermediate support plate 83 toward the rear. The rotating plate 69 has a first portion 69a extending upward from below the notch 66 and a second portion 69b extending toward the rear from the upper end of the first portion 69a, with the lower surface of the second portion 69b in surface contact with the upper surface 83a of the intermediate support plate 83.

[0124] By forming a notch 66 at the front end of the intermediate support plate 83 in this manner, the rotation of the rotating plate 69 can be restricted using the notch 66. In other words, if the rotating plate 69 is made up of a first portion 69a extending upward from below the notch 66 and a second portion 69b extending backward from the upper end of the first portion 69a, the rotation of the rotating plate 69 can be restricted first by the contact between the opening edge of the notch 66 and both left and right ends of the first portion 69a. In addition, the rotation of the rotating plate 69 can also be restricted by the surface contact between the lower surface of the second portion 69b and the upper surface 83a of the intermediate support plate 83. This makes it possible to restrict the rotation of the rotating plate 69 more reliably.

[0125] The lower surface 70 of the second part 69b and the upper surface 83a of the intermediate support plate 83 are in surface contact with the driver's seat 6 at a position where they overlap in the vertical direction.

[0126] If the lower surface 70 of the second part 69b and the upper surface 83a of the intermediate support plate 83 make surface contact at a position that overlaps with the driver's seat 6 in the vertical direction, then the contact point where the lower surface 70 of the second part 69b and the upper surface 83a of the intermediate support plate 83 make surface contact becomes difficult to see from the outside. Since friction marks and other marks are likely to occur at the contact point, if these marks and other marks become difficult to see from the outside, it becomes easier to maintain a good appearance around the driver's seat 6.

[0127] The fixing pin 58 is attached to the lower part of the intermediate support plate 83, and the intermediate support plate 83 has an upper and lower through portion 67 that exposes the upper end of the engaging member 51, which engages with the fixing pin 58, toward the upper side of the intermediate support plate 83.

[0128] According to this, the upper end of the engaging member 51 can be exposed upward from the upper and lower penetration portion 67, so even if the position (installation height) of the intermediate support plate 83 is brought closer to the support plate (upper wall 101Ab), the upper end of the engaging member 51 will not come into contact with the intermediate support plate 83. Therefore, regardless of the position (installation height) of the intermediate support plate 83, sufficient height of the engaging member 51 can be secured. In other words, since sufficient vertical dimensions can be secured for the engaging hole 59 and the guide surface 74 as the engaging member 51, it becomes possible to reliably fix the fixing pin 58 and release it.

[0129] The work machine 1 of the present invention comprises a driver's seat 6 on which the operator sits, a seat support portion (upper wall 101Ab) that supports the driver's seat 6, and the seat lock structure 50 described above.

[0130] With such a work machine 1, the driver's seat 6 can be easily fixed to the seat support in a state where its swinging is restricted.

[0131] While embodiments of the present invention have been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of equivalence to the claims are intended to be included. [Explanation of Symbols]

[0132] 1. Work machine 6. Driver's seat 6C Bottom 14. Hood 50 Seat Lock Structure 51 Engaging member 58 Fixing pins 59 Engagement holes 60 biasing member 61. Release lever 66 Notch 67 Upper and lower penetration section 68 Rotation prevention mechanism 69 Rotating Plate 69a Part 1 69b Part 2 70 Bottom side 71 1st plate part 72 2nd plate part 74 Guide surface 75 Chamfer 83 Intermediate support plate 83a top surface 91 Engine 101Ab Upper wall (support plate, sheet support section) P1 advance position P2 exit position

Claims

1. A seat lock structure that fixes a driver's seat, which is positioned to swing freely around a horizontal axis relative to a seat support, in a state in which its swinging relative to the seat support is restricted, A fixing pin is provided on the bottom surface of the driver's seat and moves between two points: an extended position and an extended position. An engaging member is provided on the upper surface of the seat support portion and engages with the fixing pin in the extended position, A biasing member that applies a biasing force to move the fixing pin in the direction of the advance position, A support plate positioned below the engagement member, Equipped with, The aforementioned engaging member is An engagement hole into which the fixing pin is inserted when it is in the extended position restricts the upward swinging of the driver's seat, An inclined guide surface that contacts the tip of the fixing pin in the extended position when the driver's seat is swung downward, and guides the tip of the fixing pin to the engagement hole while moving the fixing pin in the direction of the retracted position against the biasing force as the driver's seat swings downward, It has, The tip of the fixing pin makes point contact or line contact with the guide surface. The engaging member has a first plate portion extending upward from the upper surface of the support plate, and a second plate portion extending forward and downward from the upper end of the first plate portion and having the guide surface and the engaging hole. The first plate portion and the second plate portion are fixed to the upper surface of the support plate, and the first plate portion and the second plate portion are connected in a mountain-like manner with the upper end bent. The engaging member is a substantially inverted V-shaped member. The aforementioned fixing pin is inserted into the engagement hole so that its tip passes through the guide surface of the second plate when the driver's seat swings downward, and engages with the engagement member while in contact with the first plate. Furthermore, when inserted into the engagement hole of the second plate, its vertical movement is restricted by the engagement hole and the support plate, and when it contacts the first plate, its backward movement is restricted.

2. The driver's seat is pivotable around a pivot shaft provided at the front of the driver's seat, The aforementioned fixing pin extends in the front-rear direction, and its tip is the rear end. The engaging member is positioned behind the support shaft, The aforementioned guide surface is inclined to transition downwards as it moves forward. The seat lock structure according to claim 1, wherein the fixing pin and the engaging member do not come into contact when the driver's seat is swinging upward.

3. The aforementioned tip portion has a flat or tapered chamfered portion. The inclination angle (θ) of the guide surface with respect to the upper surface of the seat support portion. 1 ) and the inclination angle (θ) of the chamfered portion with respect to the upper surface of the sheet support portion when viewed along the axial direction of the fixing pin. 2 The seat lock structure according to claim 1, wherein the tip and the guide surface are different from each other within the range of oscillation in which the tip and the guide surface come into contact as the driver's seat swings, and the tip of the chamfered portion comes into contact with the guide surface.

4. The sheet lock structure according to claim 1, wherein the tip portion has a curved chamfered portion, and a part of the chamfered portion makes point contact with the guide surface.

5. A release lever connected to the aforementioned fixing pin, which moves the fixing pin from the extended position to the retracted position by a pulling operation, A rotation prevention mechanism that prevents the release lever from rotating around the axis of the fixing pin during the aforementioned pulling operation, The sheet lock structure according to claim 1, comprising:

6. The aforementioned rotation prevention mechanism is, A rotating plate fixed to the release lever and rotating integrally with the release lever, The sheet lock structure according to claim 5, further comprising a rotation restricting portion that restricts the rotation of the rotating plate by making surface contact with the rotating plate.

7. Below the driver's seat, an intermediate support plate is provided at a position spaced downward from the bottom surface of the driver's seat. The sheet lock structure according to claim 6, wherein the rotation restricting portion is formed on the intermediate support plate.

8. A seat lock structure for fixing a driver's seat, which is arranged to be swingable around a horizontal axis relative to a seat support, in a state in which the swinging relative to the seat support is restricted, A fixing pin is provided on the bottom surface of the driver's seat and moves between two points: an extended position and an extended position. An engaging member is provided on the upper surface of the seat support portion and engages with the fixing pin in the extended position, A biasing member that applies a biasing force to move the fixing pin in the direction of the advance position, A release lever connected to the aforementioned fixing pin, which moves the fixing pin from the extended position to the retracted position by a pulling operation, A rotation prevention mechanism that prevents the release lever from rotating around the axis of the fixing pin during the aforementioned pulling operation, Equipped with, The aforementioned engaging member is An engagement hole into which the fixing pin is inserted when it is in the extended position restricts the upward swinging of the driver's seat, An inclined guide surface that contacts the tip of the fixing pin in the extended position when the driver's seat is swung downward, and guides the tip of the fixing pin to the engagement hole while moving the fixing pin in the direction of the retracted position against the biasing force as the driver's seat swings downward, It has, The tip of the fixing pin makes point contact or line contact with the guide surface. The aforementioned rotation prevention mechanism is, A rotating plate fixed to the release lever and rotating integrally with the release lever, It has a rotation restricting part that restricts the rotation of the rotating plate by making surface contact with the rotating plate, Below the driver's seat, an intermediate support plate is provided at a position spaced downward from the bottom surface of the driver's seat. The intermediate support plate has the rotation restricting portion formed therein. The upper end of the rotating plate protrudes above the intermediate support plate. The rotation restricting portion is composed of a notch cut out from the front end of the intermediate support plate toward the rear, The rotating plate has a first portion extending upward from below the notch, and a second portion extending rearward from the upper end of the first portion. A sheet lock structure in which the lower surface of the second portion is in surface contact with the upper surface of the intermediate support plate.

9. The seat lock structure according to claim 8, wherein the lower surface of the second portion and the upper surface of the intermediate support plate are in surface contact with the driver's seat at a position that overlaps with it in the vertical direction.

10. A seat lock structure for fixing a driver's seat, which is arranged to be swingable around a horizontal axis relative to a seat support, in a state in which the swinging relative to the seat support is restricted, A fixing pin is provided on the bottom surface of the driver's seat and moves between two points: an extended position and an extended position. An engaging member is provided on the upper surface of the seat support portion and engages with the fixing pin in the extended position, A biasing member that applies a biasing force to move the fixing pin in the direction of the advance position, A release lever connected to the aforementioned fixing pin, which moves the fixing pin from the extended position to the retracted position by a pulling operation, A rotation prevention mechanism that prevents the release lever from rotating around the axis of the fixing pin during the aforementioned pulling operation, Equipped with, The aforementioned engaging member is An engagement hole into which the fixing pin is inserted when it is in the extended position restricts the upward swinging of the driver's seat, An inclined guide surface that contacts the tip of the fixing pin in the extended position when the driver's seat is swung downward, and guides the tip of the fixing pin to the engagement hole while moving the fixing pin in the direction of the retracted position against the biasing force as the driver's seat swings downward, It has, The tip of the fixing pin makes point contact or line contact with the guide surface. The aforementioned rotation prevention mechanism is, A rotating plate fixed to the release lever and rotating integrally with the release lever, It has a rotation restricting part that restricts the rotation of the rotating plate by making surface contact with the rotating plate, Below the driver's seat, an intermediate support plate is provided at a position spaced downward from the bottom surface of the driver's seat. The intermediate support plate has the rotation restricting portion formed therein. The aforementioned fixing pin is attached to the lower part of the intermediate support plate, The sheet lock structure is characterized in that the intermediate support plate has an upper and lower through portion formed therein, which exposes the upper end of the engaging member that engages with the fixing pin toward the upper side of the intermediate support plate.

11. The driver's seat where the operator sits, The seat support portion that supports the driver's seat, Claims 1 to 1, which fix the driver's seat in a state in which its swinging relative to the seat support is restricted. A sheet lock structure described in any one of item 0, A work machine equipped with the following features.

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