Brake mechanism for construction vehicles

Abstract

To provide a brake mechanism of a construction vehicle which can avoid a collision caused by a human error with a simple structure.SOLUTION: A brake mechanism of a construction vehicle includes: an obstacle detection device which detects an obstacle in a periphery of a construction vehicle; a shaft 17 which rotates around an axis in conjunction with inclining of a forward / rearward movement lever 16; a first cable 19 connecting a rotary plate 18 fixed to the shaft 17 with a forward / rearward movement switch lever 81 of a traveling pump P which causes the construction vehicle to travel; an actuator 30A provided at the construction vehicle; a second cable 82 connecting the forward / rearward movement switch lever 81 with the actuator 30A; and a control unit which causes the actuator 30A to operate and returns the forward / rearward movement switch lever 81 to a neutral position through the second cable 82 to actuate a brake when the obstacle detection device detects an obstacle.SELECTED DRAWING: Figure 27

Description

[Technical field]

[0001] The present invention relates to a brake mechanism for a construction vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a brake mechanism for a construction vehicle. In the construction vehicle of Patent Document 1, the operator operates a hydrostatic transmission (HST) brake to brake the vehicle by returning a forward / reverse lever provided in the driver's seat from a forward or reverse position to a neutral position. In addition, in the construction vehicle of Patent Document 1, the brake pedal and the forward / reverse lever are connected via a base plate and multiple rods, so that the forward / reverse lever can be returned to the neutral position by depressing the brake pedal, thereby braking the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 61-16930 Summary of the Invention [Problem to be solved by the invention]

[0004] While driving and working, trained operators check the surroundings by looking directly at objects or indirectly through the mirrors. When the operator senses danger, he or she can prevent a collision by braking the construction vehicle by operating the forward / reverse lever or stepping on the brake pedal. However, there is a problem that collisions occur due to human error caused by operators' disregard for danger or habituation.

[0005] Therefore, an object of the present invention is to provide a brake mechanism for a construction vehicle that can avoid collision accidents caused by human error with a simple structure. [Means for solving the problem]

[0006] The brake mechanism of the construction vehicle of the present invention is characterized by comprising an obstacle detection device which detects obstacles around the construction vehicle, a shaft which rotates about its axis as the forward / reverse lever is tilted, a first cable which connects a rotating plate fixed to the shaft to a forward / reverse switch lever of a traveling pump which causes the construction vehicle to travel, an actuator provided on the construction vehicle, a second cable which connects the forward / reverse switch lever to the actuator, and a control unit which, when an obstacle is detected by the obstacle detection device, activates the actuator and returns the forward / reverse switch lever to neutral via the second cable to activate the brakes.

[0007] According to the present invention, the forward / reverse switching lever can be returned to the neutral position via the actuator and the second cable when an obstacle is detected by the obstacle detection device, thereby making it possible to avoid collision accidents caused by human error with a simple structure.

[0008] In addition, it is preferable that the forward / reverse switching lever has a first notch that allows the forward / reverse switching lever to rotate by tilting the forward / reverse switching lever, and when the actuator is activated, the forward / reverse switching lever is returned to neutral by pulling the forward / reverse switching lever through the first notch.

[0009] In addition, it is preferable that the forward / reverse switching lever has a second notch hole that is continuous with the first notch hole and extends away from the rotation center of the forward / reverse switching lever, and when the actuator is activated, the second cable engaged in the second notch hole is pulled to return the inclination of the forward / reverse switching lever to neutral.

[0010] According to the present invention, the forward / reverse switching lever can be easily configured. Also, by providing the second cutout hole, the second cable can be engaged with the second cutout hole, thereby more reliably operating the brake.

[0011] Furthermore, it is preferable that the forward / reverse switch lever is configured such that the other end of a first member and one end of a second member are connected by a connecting fulcrum portion so as to be able to rotate relative to one another, the first member having a fixed fulcrum portion provided on one end side and serving as the center of rotation, and a connecting fulcrum portion provided at a distance from the fixed fulcrum portion and to which the first cable is connected, and the second member has a long hole extending in the longitudinal direction, and a movable pin provided at the tip of the second cable and movably connected to the long hole.

[0012] According to the present invention, the forward / reverse switching lever can be configured simply. Effect of the Invention

[0013] According to the present invention, collision accidents caused by human error can be avoided with a simple structure. [Brief description of the drawings]

[0014] [Figure 1] 1A and 1B are a plan view and a side view, respectively, of a brake mechanism for a construction vehicle according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic view of a main part of a brake mechanism of the construction vehicle according to the first embodiment. FIG. [Diagram 3] FIG. 3 is a view taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is a view taken along the line IV-IV in FIG. [Diagram 5] 13 is a diagram illustrating the operation of the base plate and the surrounding area when the forward / reverse lever is tilted to the maximum in the forward direction. FIG. [Figure 6] 13 is a diagram illustrating the operation of the base plate and the surrounding area when the forward / reverse lever is tilted to the maximum in the reverse direction. FIG. [Figure 7] 6 is a diagram illustrating the operation of the base plate and its surroundings when the brake pedal is depressed. [Figure 8] FIG. 2 is a block diagram of a brake mechanism of the construction vehicle according to the first embodiment. [Figure 9] FIG. 2 is a schematic diagram of a hydraulic circuit according to the first embodiment. [Figure 10] FIG. 3 is a view taken along the arrow XX in FIG. 2. [Figure 11] FIG. 11 is a side view of a main portion of a brake mechanism of a construction vehicle according to a second embodiment of the present invention. [Figure 12] FIG. 11 is a side view of a main portion of a brake mechanism of a construction vehicle according to a third embodiment of the present invention. [Figure 13A] FIG. 11 is an enlarged perspective view of a base member according to a third embodiment. [Figure 13B] FIG. 13 is an enlarged side view of a base member according to a modified example of the third embodiment. [Figure 13C] FIG. 13 is an enlarged side view of a base member according to a modified example of the third embodiment. [Figure 14] FIG. 13 is a side view of a main portion of a brake mechanism of a construction vehicle according to a fourth embodiment of the present invention. [Figure 15] FIG. 13 is a side view of a main portion of a brake mechanism of a construction vehicle according to a fifth embodiment of the present invention. [Figure 16] FIG. 13 is a side view of a main portion of a brake mechanism of a construction vehicle according to a sixth embodiment of the present invention. [Figure 17] FIG. 13 is a schematic view of a main portion of a brake mechanism of a construction vehicle according to a seventh embodiment of the present invention. [Figure 18] FIG. 13 is a side view of a main part according to the seventh embodiment. [Figure 19] 19 is an operational diagram showing the case where the forward / reverse lever in FIG. 18 is tilted to the maximum in the forward direction. [Figure 20] 19 is an operational diagram showing the case where the forward / reverse lever in FIG. 18 is tilted to the maximum in the reverse direction. [Figure 21] 19 is an operational diagram showing a case where the actuator in FIG. 18 is operated. FIG. [Figure 22] FIG. 13 is a schematic view of a main part of a brake mechanism of a construction vehicle according to an eighth embodiment of the present invention. [Diagram 23] XXIII-XXIII in Figure 22. [Figure 24] FIG. 13 is a schematic view of a main part of a brake mechanism of a construction vehicle according to a ninth embodiment of the present invention. [Diagram 25] FIG. 13 is a side view of a main portion of a brake mechanism of a construction vehicle according to a ninth embodiment. [Figure 26]FIG. 11 is a schematic diagram showing the relationship between a conventional forward / reverse lever and a forward / reverse switching lever. [Figure 27] FIG. 10 is a schematic diagram of a brake mechanism for a construction vehicle according to a tenth embodiment of the present invention. [Figure 28] FIG. 23 is an enlarged view of a forward / reverse switching lever according to a modified example of the tenth embodiment. [Figure 29] FIG. 23 is an enlarged view of a forward / reverse switching lever according to a modified example of the tenth embodiment. [Diagram 30] FIG. 23 is a schematic diagram of a brake mechanism for a construction vehicle according to an eleventh embodiment of the present invention. [Diagram 31] FIG. 23 is an operational diagram of the brake mechanism of the construction vehicle according to the eleventh embodiment during forward movement. [Diagram 32] FIG. 23 is an operational diagram of the brake mechanism of the construction vehicle according to the eleventh embodiment when the vehicle is moving backward. [Diagram 33] FIG. 23 is an operational diagram showing a case where an actuator of a brake mechanism of a construction vehicle according to an eleventh embodiment is operated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] A brake mechanism 1 for a construction vehicle according to a first embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, the brake mechanism 1 for a construction vehicle according to this embodiment is mounted on a construction vehicle such as a compaction roller that performs work while traveling at a low speed. In this embodiment, a compaction roller is illustrated, but the present invention may also be applied to other construction vehicles. Note that the following "up and down," "front and back," and "left and right" follow the arrows in FIG. 1.

[0016] 1 shows a case where a brake mechanism 1 for a construction vehicle is mounted on a rolling roller 10 that rolls asphalt road surfaces with rollers 11A and tires 11B. The rolling roller 10 includes a driver's seat 12, a dashboard 13, a steering wheel 14, a brake pedal 15, and a forward / reverse lever 16.

[0017] The driver's seat 12 is where the operator sits, and faces the dashboard 13. The dashboard 13 is a box-shaped body installed in front of the driver's seat, and various instruments, buttons, knobs, etc. are arranged on the upper surface. The handle 14 is a device for determining the traveling direction of the vehicle, and is provided on the upper surface of the dashboard 13.

[0018] The steering wheel 14 is connected to an Orbitroll (registered trademark, the same applies below; see FIG. 10) 14a provided inside an upper surface 13c (see FIG. 10) of the dashboard 13. The Orbitroll 14a is a hydraulic motor that constitutes part of the steering device. The Orbitroll 14a is supplied with hydraulic oil via a pipe 14b that is connected to a hydraulic circuit (not shown).

[0019] 1, the brake pedal 15 is provided under the dashboard 13 and configured to apply the brakes when the operator steps on it. The forward / reverse lever 16 is provided on both sides of the dashboard 13 and is a lever that can be tilted to a neutral position, a forward position, and a reverse position. The forward / reverse lever 16 may be configured to be provided on only one side of the dashboard 13.

[0020] As shown in Fig. 2, the forward / reverse levers 16, 16 are vertically connected to both ends of a shaft 17. The shaft 17 is arranged inside the dashboard 13 along the width direction. As shown in Figs. 2 and 3, a plate-shaped rotating plate 18 that rotates in sync with the shaft 17 is fixed vertically through the shaft 17. A connecting fulcrum portion 18b is formed at an end of a main body portion 18a of the rotating plate 18. A first cable 19 is connected to the connecting fulcrum portion 18b by a pin connection. One end of the first cable 19 is connected to the connecting fulcrum portion 18b, and the other end is connected to a forward / reverse switching lever (not shown) of the travel pump P (see Fig. 9).

[0021] As shown in Figs. 2 and 3, when the forward / reverse lever 16 is pushed to the forward position, the roller 10 moves forward, when the lever is pushed to the reverse position, the roller 10 moves backward, and when the lever is returned to the neutral position, the roller 10 is braked. That is, when the lever 16 is pushed to the forward position, the rotating plate 18 rotates upward about the axis of the shaft 17 and pulls the first cable 19. This causes the forward / reverse switching lever to rotate to the forward position and the roller 10 moves forward. On the other hand, when the lever 16 is pushed to the reverse position, the rotating plate 18 rotates downward about the axis of the shaft 17 and pushes the first cable 19. This causes the switching lever to rotate to the reverse position and the roller 10 moves backward. Also, when the lever 16 is returned to the neutral position, the HST brake described later is activated and the roller 10 is braked.

[0022] The brake pedal 15 is configured to move in conjunction with the shaft 17, as shown in Figures 2 and 4. A plate-shaped base plate 22 that rotates in synchronization with the shaft 17 is fixed vertically through the shaft 17. The base plate 22 is formed with a first pin 22a that is provided vertically on the rear left side surface and a second pin 22b that is provided vertically on the front right side surface. The first pin 22a and the second pin 22b are disposed at approximately the same distance from the shaft 17. The brake pedal 15 includes a main body plate 15a, a pedal portion 15b, a rotation fulcrum portion 15c, and a connecting fulcrum portion 15d.

[0023] The main body plate 15a is a plate-like member having a pedal portion 15b at the rear. The front end of the main body plate 15a is rotatably fixed via a bracket BK fixed to the front wall 13a of the dashboard 13. The rotation fulcrum portion 15c is the rotation center of the brake pedal 15. The connecting fulcrum portion 15d is formed at the upper center of the main body plate 15a.

[0024] The connecting fulcrum portion 15d is connected to the base plate 22 via a first brake pedal rod 23 and a second brake pedal rod 24. The first brake pedal rod 23 and the second brake pedal rod 24 are rod-shaped members. The lower ends of the first brake pedal rod 23 and the second brake pedal rod 24 are connected to the connecting fulcrum portion 15d by pin connection.

[0025] An elongated hole 23a into which the first pin 22a fits loosely is formed at the upper end of the first brake pedal rod 23. An elongated hole 24a into which the second pin 22b fits loosely is formed at the upper end of the second brake pedal rod 24. When viewed from the side, the first brake pedal rod 23 and the second brake pedal rod 24 are V-shaped.

[0026] In the initial position (when the forward / reverse lever 16 is in the neutral position), the base plate 22 is generally horizontal. The first pin 22a and the second pin 22b are located slightly above the center in the height direction of the long holes 23a and 24a.

[0027] Fig. 5 is an action diagram around the base plate 22 when the forward / reverse lever 16 is tilted to the maximum in the forward direction. As shown in Fig. 5, when the forward / reverse lever 16 is tilted in the forward direction, the shaft 17 and the base plate 22 rotate counterclockwise around the shaft 17. At this time, the first pin 22a is located at the upper end of the long hole 23a of the first brake pedal rod 23. On the other hand, the second pin 22b is located slightly below the center in the height direction of the long hole 24a of the second brake pedal rod 24. Even if the forward / reverse lever 16 is tilted in the forward direction, the position of the brake pedal 15 does not change because the first pin 22a and the second pin 22b move within the long holes 23a, 24a.

[0028] Fig. 6 is an action diagram around the base plate 22 when the forward / reverse lever 16 is tilted to the maximum in the reverse direction. As shown in Fig. 6, when the forward / reverse lever 16 is tilted in the reverse direction, the shaft 17 and the base plate 22 rotate clockwise around the shaft 17. At this time, the second pin 22b is located at the upper end of the long hole 24a of the second brake pedal rod 24. On the other hand, the first pin 22a is located slightly below the center in the height direction of the long hole 23a of the first brake pedal rod 23. Even if the forward / reverse lever 16 is tilted in the reverse direction, the position of the brake pedal 15 does not change because the first pin 22a and the second pin 22b move within the long holes 23a, 24a.

[0029] Fig. 7 is an action diagram around the base plate 22 when the brake pedal is depressed. As shown in Fig. 7, when the operator depresses the brake pedal 15, the brake pedal 15 rotates downward around the rotation fulcrum 15c. As a result, the first brake pedal rod 23 and the second brake pedal rod 24 are pulled downward, so that the first pin 22a and the second pin 22b are positioned at the upper ends of the long holes 23a and 24a, respectively, and the base plate 22 rotates at a predetermined angle and becomes approximately horizontal. In synchronization with this, the shaft 17 and the rotating plate 18 also rotate and are positioned in the neutral position, so that the HST brake is activated and braking is performed.

[0030] As described above, the operator can brake the compaction roller 10 by returning the forward / reverse lever 16 to the neutral position, or by depressing the brake pedal 15 to return the forward / reverse lever 16 to the neutral position. In other words, the above-mentioned configuration is a braking means operated by the operator.

[0031] Next, the brake means 6 (6A, 6B) operated by the control device (control section) 3 will be described.

[0032] Fig. 8 is a block diagram of the brake mechanism of the construction vehicle according to the first embodiment. As shown in Fig. 1 and Fig. 8, the brake mechanism 1 of the construction vehicle includes a TOF (Time Of Flight) type distance image sensor (3D distance sensor) 2 that measures distance from the time difference between projected light and reflected light, and a control device (controller) 3 (see Fig. 8) that determines the presence or absence of an obstacle G based on the measurement data of the distance image sensor 2. The obstacle G is, for example, a structure such as a pillar or a wall, or a person.

[0033] The distance image sensor (obstacle detection device) 2 includes a light-emitting unit that emits projected light such as infrared light, and a light-receiving unit that receives the reflected light when the projected light hits an object. The distance to the object is measured by measuring the time from when the infrared light is sent from the light-emitting unit to when the reflected light is received by the light-receiving unit. The projection angle from the distance image sensor 2 is, for example, 95° in the horizontal direction and 32° in the vertical direction (symbol θ1 shown in FIG. 1(b)), and the projection cross section has a horizontally elongated rectangular shape. The image resolution is, for example, 64 pixels in the horizontal direction and 16 pixels in the vertical direction, totaling 1024 pixels. The distance image sensor 2 is attached to the center of the vehicle width direction at the rear of the rolling roller 10 so that the projected light is projected diagonally downward in the backward direction.

[0034] Regarding the detection range of the obstacle G, if the projection range of the projected light is set as the detection range as it is, that is, if the dimension L1 (FIG. 1(a)) in the vehicle width direction is set wider than the vehicle width dimension of the compaction roller 10, the obstacle G will be recognized even though there is no risk of collision, and the vehicle will stop unnecessarily. Therefore, in this embodiment, the dimension L1 of the detection range 4 in the vehicle width direction (shown by diagonal lines in FIG. 1) is set to be approximately the same as the vehicle width dimension of the compaction roller 10. Since the distance image sensor 2 can measure the distance to the obstacle G, the control device 3 can determine whether or not the obstacle G is present in the detection range 4 set to the vehicle width dimension from the measurement data for each pixel, specifically, the distance between the distance image sensor 2 and the obstacle G in the vehicle width direction. By using the distance image sensor 2 in this way, the dimension L1 of the detection range 4 can be ensured to be constant over the front-rear direction of the vehicle. That is, the detection range 4 can be easily set to an approximately rectangular range with one side having the dimension L1 in a plan view as shown in FIG. 1(a). A dimension L2 of the detection range 4 in the vehicle longitudinal direction is appropriately set according to the usual running speed, and in this embodiment is set to, for example, about 3 meters.

[0035] In addition, since the projection light of the distance image sensor 2 is projected obliquely downward in the backward travel direction, the lateral angle θ2 of the projection light in a plan view is greater than 95°. Therefore, the distance L3 in the vehicle front-rear direction of the non-detection ranges 5, 5 formed between the detection range 4 and both rear ends of the compaction roller 10 can be kept small. In other words, the non-detection blind spots formed on both sides of the rear of the vehicle can be reduced.

[0036] The control device (control unit) 3 is provided with a brake means 6A that applies the brakes to the vehicle when it is determined that an obstacle G is present within the detection range 4, as shown in Fig. 9. A travel pump P driven by an engine (not shown) and a travel motor M that rotates the rollers 11A and tires 11B (Fig. 1) are connected in series to form a hydraulic closed circuit U1. The travel pump P is a swash plate type pump. An oil passage T1 and an oil passage T2 for operating the swash plate are connected to the travel pump P. A two-position three-port solenoid valve V1 is provided between the oil passage T1 and the oil passage T2 in parallel with the travel pump P.

[0037] When the engine is running, the solenoid valve V1 is in the right position in FIG. 9, and the oil passage T1 and the oil passage T2 are not connected to each other. Therefore, when the engine is running, tilting the forward / reverse lever 16 around the driver's seat to the forward position side causes the swash plate hydraulic oil to flow from the oil passage T1 side to the oil passage T2 side, and the swash plate tilts to one side. As a result, pressure oil flows in one direction in the closed circuit U1, the traveling motor M rotates in one direction, and the vehicle moves forward. When the forward / reverse lever 16 is tilted to the reverse position side, the swash plate hydraulic oil flows from the oil passage T2 side to the oil passage T1 side, and the swash plate tilts to the other side. As a result, pressure oil flows in the other direction in the closed circuit UI, the traveling motor M rotates in the other direction, and the vehicle moves backward.

[0038] When the engine is not running, the solenoid valve V1 is in the left position as shown in Figure 9, and the oil passages T1 and T2 are in communication. A hydraulic closed circuit U2 is formed between the solenoid valve V1 and the travel pump P, and no pressure difference occurs between the oil passages T1 and T2, so the swash plate is in the neutral position. This causes the HST (Hydro Static Transmission) brake to act in the closed circuit U1.

[0039] The braking means 6A of this embodiment utilizes this electromagnetic valve V1, and when an obstacle is detected during reverse travel, the control device 3 outputs a brake signal to switch the electromagnetic valve V1 from the right position to the left position. As a result, even if the engine is running and the forward / reverse lever remains tilted toward the reverse position, the swash plate is positioned in the neutral position, and the HST brake is applied in the closed circuit U1 to stop the traveling motor M. Note that a solenoid valve V2 for operating the negative brake M1 during parking is provided between the charge pump P1 built into the traveling pump P and the negative brake M1 built into the traveling motor M.

[0040] It is preferable that the timing from when the control device 3 determines that there is an obstacle G until when it outputs a brake signal, that is, the timing when the braking means 6A starts braking, is changed according to the traveling speed of the vehicle. For example, the control device 3 compares a brake start distance preset according to the traveling speed with the distance to the obstacle G present in the detection range 4 measured by the distance image sensor 2, and outputs a brake signal to the electromagnetic valve V1 when the distance to the obstacle G becomes equal to or shorter than the brake start distance.

[0041] The braking start distance is preferably set to a distance with a slight margin from the vehicle's actual measured limit braking distance, for example. The braking start distance is set to approximately 0.5 m at 2 km / h, approximately 1 m at 4 km / h, approximately 1.6 m at 6 km / h, and approximately 2.4 m at 8 km / h. Note that the vehicle speed sensor 7 (FIG. 8) that detects the vehicle's traveling speed may be a proximity sensor such as a rotary encoder that detects the number of tire rotations.

[0042] In this embodiment, as shown in Fig. 8, the control device (controller) 3 includes a brake means 6B that applies the brakes to the vehicle when it is determined that an obstacle G is present within the detection range 4. As shown in Fig. 10, the brake means 6B includes an actuator 30, a link plate 31, a base member 32, a first link rod 33, and a second link rod 34.

[0043] The actuator 30 is a device that operates the output shaft 30a in the height direction based on a brake signal from the control device 3. The actuator 30 can be various cylinders such as an air cylinder or an electric cylinder, but in this embodiment, a hydraulic cylinder is used. The actuator 30 can be set anywhere on the vehicle body, but in this embodiment, it is installed on the front surface of the front wall 13a of the dashboard 13 via a bracket BK. The actuator 30 is connected to a hydraulic circuit provided inside the vehicle via piping (not shown).

[0044] The link plate 31 is a plate-like member that connects the actuator 30 to the first link rod 33 and the second link rod 34. The link plate 31 includes a main body portion 31a, a fixed fulcrum portion 31b, a connecting fulcrum portion 31c, and a connecting fulcrum portion 31d. The main body portion 31a is disposed by being inserted through an opening 13d formed in the front wall 13a of the dashboard 13.

[0045] The fixed fulcrum 31b is provided on the upper part of the main body 31a and is rotatably fixed to the front surface of the front wall 13a via a bracket BK. The connecting fulcrum 31c is provided on the front end part of the main body 31a and is connected to the tip of the output shaft 30a of the actuator 30 by a pin connection. The connecting fulcrum 31d is provided on the upper part of the rear end part of the main body 31a and is connected to the lower ends of the first link rod 33 and the second link rod 34 by pin connections.

[0046] The base member 32 is a plate-like member that rotates in synchronization with the shaft 17. The base member 32 is fixed to the shaft 17 while perpendicularly penetrating the shaft 17. The base member 32 is formed with a first pin 32a that is vertically provided on the rear left side surface and a second pin 32b that is vertically provided on the front right side surface. The first pin 32a and the second pin 32b are disposed at approximately the same distance from the shaft 17.

[0047] The first link rod 33 is a rod-shaped member that connects the connection fulcrum portion 31d and the first pin 32a. The first link rod 33 has an elongated hole 33a at its upper end, into which the first pin 32a fits loosely. The second link rod 34 has an elongated hole 34a at its upper end, into which the second pin 32b fits loosely. When viewed from the side, the first link rod 33 and the second link rod 34 have a V-shape. In the claims, the term "connection mechanism that connects the output shaft of the actuator and the base member" refers to a link mechanism that includes the link plate 31, the first link rod 33, and the second link rod 34 in this embodiment.

[0048] In the initial position (when the forward / reverse lever 16 is in the neutral position), the base member 32 is generally horizontal. The first pin 32a and the second pin 32b are located slightly above the center in the height direction of the long holes 33a and 34a.

[0049] When the forward / reverse lever 16 is tilted to move forward or backward, the first pin 32a and the second pin 32b move within the elongated holes 33a, 34a, respectively, as the shaft 17 and the base member 32 rotate, in the same manner as in the braking by the brake pedal 15 described above. In other words, as the forward / reverse lever 16 is tilted, the first pin 32a and the second pin 32b move within the elongated holes 33a, 34a, and the position of the link plate 31 does not change.

[0050] On the other hand, for example, when an obstacle G is detected by the distance image sensor 2 while moving backward, the control device 3 outputs a brake signal to operate the actuator 30. When the output shaft 30a of the actuator 30 is pulled, the rear end side of the link plate 31 rotates downward around the fixed fulcrum part 31b. As a result, the first link rod 33 and the second link rod 34 are pulled downward, so that the first pin 32a and the second pin 32b are positioned at the upper ends of the long holes 33a and 34a, respectively, and the base member 32 rotates by a predetermined angle and becomes approximately horizontal. In synchronization with this, the shaft 17 and the rotating plate 18 also rotate and are positioned in the neutral position, so that the HST brake is activated to brake.

[0051] After the forward / reverse lever 16 is returned to the neutral position by the brake means 6B, the actuator 30 is operated to extend the output shaft 30a to its original position, thereby returning it to the initial position (the state in FIG. 10).

[0052] According to the brake mechanism 1 of the construction vehicle of this embodiment described above, since it is equipped with the brake means 6B, the forward / reverse lever 16 can be automatically returned to neutral upon detection by the distance image sensor (obstacle detection device) 2, and the HST brake can be activated, and collision accidents due to human error can be avoided with a simple structure.

[0053] Furthermore, according to this embodiment, the output shaft 30a of the actuator 30 is connected to the base member 32 by a link mechanism including the link plate 31, the first link rod 33, and the second link rod 34, so that a simple structure can be achieved. Also, the brake means 6B can be attached to an existing compaction roller 10.

[0054] In addition, since the first pin 32a and the second pin 32b are movable through the long holes 33a, 34a, normal forward and reverse operations do not affect the actuator 30 and the link plate 31.

[0055] In addition, since this embodiment is equipped with both braking means 6A, 6B, it is possible to operate both the brake of the solenoid valve V1 system and the brake of the actuator 30 system, thereby more reliably braking the compaction roller 10. In this embodiment, both the brake means 6A and 6B are provided, but the brake means 6A may not be provided.

[0056] [Second embodiment] Next, a brake mechanism 1A for a construction vehicle according to a second embodiment of the present invention will be described. As shown in Fig. 11, in the brake mechanism 1A for a construction vehicle according to the second embodiment, the brake means 6Ba is different from that of the first embodiment. In the second embodiment, the differences from the first embodiment will be mainly described.

[0057] The brake means 6Ba includes an actuator 30A, a link plate 31A, a base member 32, a first link rod 33, a second link rod 34, and a cable 37.

[0058] The actuator 30A is a device that operates the output shaft 30Aa based on a brake signal from the control device 3. The link plate 31A is a plate-like member having a substantially triangular shape. The link plate 31A includes a main body portion 31a, a fixed fulcrum portion 31b, a connecting fulcrum portion 31c, and a connecting fulcrum portion 31d. The main body portion 31a is disposed inside the dashboard 13.

[0059] The fixed fulcrum 31b is provided at the front end of the main body 31a and is rotatably fixed to the rear surface of the front wall 13a via a bracket BK. The connecting fulcrum 31c is provided at the lower center of the main body 31a and is connected to a cable 37 by a pin connection. One end of the cable 37 is connected to the connecting fulcrum 31c and the other end is connected to the output shaft 30Aa of the actuator 30A. The connecting fulcrum 31d is provided at the rear end of the main body 31a and is connected to the lower ends of the first link rod 33 and the second link rod 34 by pin connections.

[0060] In the claims, the “connecting mechanism that connects the output shaft of the actuator and the base member” means, in this embodiment, a link mechanism including link plate 31A, first link rod 33, second link rod 34, and cable 37.

[0061] For example, when an obstacle is detected by the distance image sensor 2 during reverse travel, the control device 3 outputs a brake signal to activate the actuator 30A. When the output shaft 30a of the actuator 30A pulls the cable 37, the rear end of the link plate 31A rotates downward around the fixed fulcrum 31b. As a result, the first link rod 33 and the second link rod 34 are pulled downward, so that the first pin 32a and the second pin 32b are positioned at the upper ends of the long holes 33a and 34a, respectively, and the base member 32 rotates at a predetermined angle and becomes approximately horizontal. In synchronization with this, the shaft 17 and the rotating plate 18 also rotate and are positioned in the neutral position, so that the HST brake is activated to apply braking.

[0062] The brake mechanism 1A for a construction vehicle according to the second embodiment described above can achieve substantially the same effects as the first embodiment. The actuator 30A of the brake means 6Ba may be provided anywhere within the compaction roller 10. As in this embodiment, the link plate 31A may be rotated via a cable 37. Using the cable 37 increases the degree of freedom in the installation position of the actuator 30A.

[0063] [Third embodiment] Next, a brake mechanism 1B for a construction vehicle according to a third embodiment will be described. As shown in Fig. 12, the brake mechanism 1B for a construction vehicle according to the third embodiment differs from the first embodiment in the brake means 6Bb. The third embodiment will be described mainly with respect to the parts that differ from the first embodiment.

[0064] The brake means 6Bb includes an actuator 30, a link plate 31, a base member 41, an engaging jig 42, and a connecting jig 43.

[0065] As shown in FIG. 12 and FIG. 13A, the base member 41 is a plate-like member that rotates in synchronization with the shaft 17. The base member 41 is fixed vertically to the shaft 17 through the shaft 17. The base member 41 includes a main body 41a, a first notch hole 41b, and a second notch hole 41c. The first notch hole 41b is formed in a substantially arc shape so as to be convex downward. The second notch hole 41c is formed below the center of the first notch hole 41b and continues to the first notch hole 41b. The second notch hole 41c is formed in a substantially semicircular shape so as to be convex downward. The first notch hole 41b has a sufficiently large opening relative to the second notch hole 41c.

[0066] The engagement jig 42 is a member that connects the base member 41 and the connecting jig 43, and in this embodiment, a clevis is used. The engagement jig 42 has a bifurcated main body portion 42a and a connector 42b that connects the tip ends of the main body portion 42a. The connector 43 is a rod-shaped member that connects the engagement jig 42 and the connecting fulcrum portion 31d. The engagement jig 42 is arranged so that the lower part of the base member 41 is rotatably inserted into the hollow portion formed by the main body portion 42a and the connector 42b. The engagement jig 42 is always upright, and the connector 42b is located inside the first notch 41b.

[0067] Here, the position directly below the axis of the shaft 17 and distance h away is defined as the setback center C1. The radius from the axis of the shaft 17 to the upper edge 41d of the first cutout hole 41b is defined as radius r1. The radius from the axis of the shaft 17 to the axis of the connector 42b is defined as radius r2. The radius from the setback center C1 to the lower edge 41e of the first cutout hole 41b is defined as radius r3.

[0068] In the present embodiment, the term "connecting mechanism for connecting the output shaft of the actuator and the base member" in the claims refers to a mechanism made up of the link plate 31, the engaging jig 42, and the connecting jig 43.

[0069] In the initial position (when the forward / reverse lever 16 is in the neutral position), the connector 42b is located approximately in the center of the first notch 41b, as shown in Fig. 13A. When the forward / reverse lever 16 is switched to the forward position or the reverse position, the shaft 17 and the base member 41 rotate accordingly around the shaft 17. At this time, since the first notch 41b is formed, the base member 41 and the engaging jig 42 do not interfere with each other, allowing the base member 41 to rotate.

[0070] On the other hand, for example, when an obstacle G is detected by the distance image sensor 2 during reverse travel, the control device 3 outputs a brake signal to drive the actuator 30. When the output shaft 30a of the actuator 30 is pulled, the rear end side of the link plate 31 rotates downward around the fixed fulcrum portion 31b, and the engagement jig 42 is also pulled downward. As a result, the tilted base member 41 engages with the second cutout hole 41c while the connector 42b slides on the lower edge 41e of the first cutout hole 41b. Furthermore, the second cutout hole 41c is returned to the initial position by the engagement jig 42, so that the shaft 17 and the rotating plate 18 are located in the neutral position. As a result, the HST brake is activated to brake.

[0071] The brake mechanism 1B for a construction vehicle according to the third embodiment described above can achieve substantially the same effects as those of the first embodiment. Even if the base member 41 is used as in this embodiment, the actuator 30 of the brake means 6Bb can be operated to return the shaft 17 and the rotating plate 18 to the neutral position.

[0072] 13B and 13C are enlarged side views of a base member according to a modified example of the third embodiment. As shown in FIG. 13B, the second cutout hole may be omitted. In this modified example, the lower edge 41e of the first cutout hole 41b is pulled by the connector 42b of the engagement jig 42, so that the tilted base member 41 can be returned to the neutral position.

[0073] 13C, the shape of the second cutout hole 41c may be triangular in side view. By providing the second cutout hole 41c extending downward from the lowermost edge of the first cutout hole 41b as shown in Figs. 13A and 13C, the connector 42b of the engagement jig 42 can be easily engaged, so that the force for returning to the neutral position and the force for maintaining the neutral position (while the actuator 30 is operating) can be increased.

[0074] The second cutout hole 41c is not limited to the above shape, and may have other shapes as long as it can be engaged with or disengaged from the connector 42b. 13A to 13C, the setback center C1 of radius r3 may be offset by a distance h from the axis of the shaft 17, or, although not specifically shown, the radii r1, r2, and r3 may be concentric circles (distance h is zero). The first cutout hole 41b (second cutout hole 41c) and radii r1, r2, r3 may be appropriately set so that when the forward / reverse lever 16 is tilted, the base member 41 and the engaging jig 42 do not interfere with each other, allowing the base member 41 to rotate, and when the actuator 30 is activated, the engaging jig 42 can be pulled to return the tilted base member 41 to the neutral position.

[0075] As described above, even if the radii r1, r2, and r3 are concentric (the distance h is zero), this can be achieved if the second cutout hole 41c is sufficiently large. "Sufficiently large" means that the size and shape of the first cutout hole 41b and the second cutout hole 41c are determined so that the connector 42b is located below (outside the center) the arc drawn by the radius r3 when the connector 42b is pulled in the vertical direction when the base member 41 rotates to the front or rear and reaches the maximum tilt angle.

[0076] [Fourth embodiment] Next, a brake mechanism 1C for a construction vehicle according to a fourth embodiment of the present invention will be described. As shown in Fig. 14, in the brake mechanism 1C for a construction vehicle according to the fourth embodiment, the brake means 6Bc is different from that of the first embodiment. In the fourth embodiment, the differences from the first embodiment will be mainly described.

[0077] As described above, the orbit roll 14a is provided with the piping 14b connected to a hydraulic circuit (not shown). In this embodiment, the piping 14b is provided with the branch pipe 14c and the bypass pipe 14d. The branch pipe 14c and the bypass pipe 14d connect the piping 14b to the actuator 30. This allows the actuator 30, which is a hydraulic cylinder, to supply hydraulic oil to the actuator 30 by utilizing the existing piping 14b. This makes it possible to easily configure a hydraulic circuit according to this embodiment.

[0078] [Fifth embodiment] Next, a brake mechanism 1D for a construction vehicle according to a fifth embodiment of the present invention will be described. As shown in Fig. 15, in the brake mechanism 1D for a construction vehicle according to the fifth embodiment, the brake means 6Bd is different from that of the first embodiment. In the fifth embodiment, the differences from the first embodiment will be mainly described.

[0079] The brake means 6Bd includes an actuator 30, a link plate 31D, a base member 32, a first link rod 33, a second link rod 34, and a brake pedal rod 51. When the actuator 30 is operated, the brake means 6Bd rotates the base member 32 and also rotates the brake pedal 15D in conjunction with the rotation of the base member 32.

[0080] The front end of the brake pedal rod 51 is connected to the connection fulcrum 31e of the link plate 31D by a pin connection. A long hole 51a is formed on the rear end side of the brake pedal rod 51. An engagement pin 15e is vertically provided on the main body plate 15a of the brake pedal 15D. The engagement pin 15e is loosely fitted into the long hole 51a. The connection fulcrum 31e is located below and forward of the engagement pin 15e. The rear end of the brake pedal 15D is exposed to the outside through an opening 13e formed in the rear wall 13b of the dashboard 13.

[0081] When the operator depresses the brake pedal 15D, the base plate 22 (see FIG. 7) returns to the neutral position (horizontal) and the HST brake is activated to apply braking, as in the first embodiment. At this time, the engagement pin 15e of the brake pedal 15D moves forward within the elongated hole 51a, so that the link plate 31D does not rotate when the brake pedal 15D is depressed.

[0082] On the other hand, for example, when an obstacle is detected by the distance image sensor 2 while moving backward, the control device 3 outputs a brake signal to activate the actuator 30. This causes the base member 32 to become approximately horizontal in the same manner as in the first embodiment. In synchronization with this, the shaft 17 and the rotating plate 18 also rotate and are located in the neutral position, so that the HST brake is activated to brake. In addition, the link plate 31D rotates clockwise around the fixed fulcrum part 31b, so that the brake pedal rod 51 is pulled diagonally downward to the front side, and the brake pedal 15D is rotated in the actuating direction by the brake pedal rod 51.

[0083] As a result, the actuator 30 can be operated to operate the HST brakes even with the brake pedal 15 system, thereby performing braking. According to the fifth embodiment, one actuator 30 can link the link mechanism including the link plate 31D with the brake pedal 15D, so that the HST brakes can be operated with two systems, thereby performing braking more reliably.

[0084] [Sixth embodiment] Next, a brake mechanism 1E for a construction vehicle according to a sixth embodiment of the present invention will be described. As shown in Fig. 16, the brake mechanism 1E for a construction vehicle according to the sixth embodiment is a modified example of the second embodiment. In the brake mechanism 1E for a construction vehicle according to the sixth embodiment, the brake means 6Be is different from that of the second embodiment. The sixth embodiment will be described mainly with respect to the parts that differ from the second embodiment.

[0085] The brake means 6Be includes an actuator 30A, a link plate 31E, a base member 32, a first link rod 33, a second link rod 34, a cable 37, and a brake pedal rod 51. When the actuator 30A is operated, the brake means 6Be rotates the base member 32 and also rotates the brake pedal 15E in conjunction with the rotation of the base member 32.

[0086] The link plate 31E includes a main body 31a, a fixed fulcrum 31b, a connecting fulcrum 31c, a connecting fulcrum 31d, and a connecting fulcrum 31e. The fixed fulcrum 31b is provided on the front side of the main body 31a and is rotatably fixed to the rear surface of the front wall 13a via a bracket BK.

[0087] The connecting fulcrum portion 31c protrudes forward from the fixed fulcrum portion 31b and protrudes forward from an opening 13d in the front wall 13a. The connecting fulcrum portion 31c is connected to an end of a cable 37 by a pin connection.

[0088] The connecting fulcrum 31d is provided on the upper part of the main body 31a, and is connected to the lower ends of the first link rod 33 and the second link rod 34 by pin connections. The connecting fulcrum 31e is connected to the front end of the brake pedal rod 51 by pin connections. A long hole 51a is formed on the rear end side of the brake pedal rod 51. An engagement pin 15e formed on the brake pedal 15E is loosely fitted into the long hole 51a. The connecting fulcrum 31e is located below and in front of the engagement pin 15e. The rear end of the brake pedal 15E is exposed to the outside from an opening 13e formed in the rear wall 13b of the dashboard 13.

[0089] When the operator depresses the brake pedal 15E, the base plate 22 (see FIG. 7) returns to the neutral position (horizontal) and the HST brake is activated to apply braking, as in the first embodiment. At this time, the engagement pin 15e of the brake pedal 15E moves forward within the long hole 51a, so that the link plate 31E does not rotate when the brake pedal 15E is depressed.

[0090] On the other hand, for example, when an obstacle is detected by the distance image sensor 2 while reversing, the control device 3 outputs a brake signal to activate the actuator 30A. This causes the base member 32 to become approximately horizontal in the same manner as in the first embodiment. In synchronization with this, the shaft 17 and the rotating plate 18 also rotate to the neutral position, and the HST brake is activated to brake. In addition, the link plate 31E is pushed by the cable 37 and rotates clockwise around the fixed fulcrum part 31b. This causes the brake pedal rod 51 to be pulled diagonally downward to the front side, and the brake pedal 15E rotates in the actuating direction.

[0091] In other words, by operating the actuator 30A, the HST brake can be operated in the brake pedal 15E system as well to perform braking. According to the sixth embodiment, the single actuator 30A can link the link mechanism including the link plate 31E and the brake pedal 15E, so that the HST brake can be operated in two systems to perform braking more reliably.

[0092] [Seventh embodiment] Next, a brake mechanism 1F for a construction vehicle according to a seventh embodiment of the present invention will be described. As shown in Fig. 17, in the brake mechanism 1F for a construction vehicle according to the seventh embodiment, the brake means 6Bf is different from that of the first embodiment. In the seventh embodiment, the differences from the first embodiment will be mainly described.

[0093] As shown in FIGS. 17 and 18, the brake means 6Bf includes a rotating plate 18A, a connecting plate 61, a second cable 62, and an actuator 30A.

[0094] The rotating plate 18A is a plate-like member having a substantially triangular shape. A shaft 17 that rotates in synchronization with the rotating plate 18A is fixed vertically through the front part of the rotating plate 18A. The rotating plate 18A includes a main body 18a, a connecting fulcrum part 18b, and a connecting fulcrum part (connecting pin) 18c. The axis of the shaft 17, the connecting fulcrum part 18b, and the connecting fulcrum part 18c are provided near each corner of the triangle of the main body 18a. The connecting fulcrum part 18b is provided at the bottom of the main body 18a, and is a portion to which an end of the first cable 19 is connected by a pin connection.

[0095] The connection fulcrum (connection pin) 18c is provided on the upper part of the main body 18a, and is a portion to which the connection plate 61 is connected by a pin connection. The connection plate 61 is a rectangular plate-like member, and is a member that connects the rotating plate 18A and the second cable 62. A long hole 61a is formed in the connection plate 61. The second cable 62 is provided with a movable pin 63 at one end, and the other end is connected to the actuator 30A. The movable pin 63 is loosely fitted in the long hole 61a.

[0096] Fig. 19 is an operation diagram showing a case where the forward / reverse lever is tilted most in the forward direction in Fig. 18. As shown in Fig. 19, when the operator tilts the forward / reverse lever 16 in the forward direction, the rotating plate 18A rotates counterclockwise around the shaft 17. This pulls the first cable 19, and the forward / reverse switching lever (not shown) of the traveling pump P rotates to the forward position. At this time, the rotating plate 18A and the connecting plate 61 rotate relatively around the connecting fulcrum part 18c, and the movable pin 63 moves within the long hole 61a.

[0097] Fig. 20 is an operation diagram showing a case where the forward / reverse lever is tilted most in the reverse direction in Fig. 18. As shown in Fig. 19, when the operator tilts the forward / reverse lever 16 in the reverse direction, the rotating plate 18A rotates clockwise around the shaft 17. This pushes the first cable 19, and the forward / reverse switching lever (not shown) of the traveling pump P rotates to the reverse position. At this time, the rotating plate 18A and the connecting plate 61 rotate relatively around the connecting fulcrum part 18c, and the movable pin 63 moves within the long hole 61a.

[0098] In other words, even if the forward / reverse lever 16 is tilted in the forward or reverse direction, no load is applied to the actuator 30A because the connecting plate 61 and the elongated hole 61a are formed.

[0099] On the other hand, for example, when an obstacle is detected by the distance image sensor 2 while reversing, the control device 3 outputs a brake signal to activate the actuator 30A. As shown in Fig. 21, when the second cable 62 is pulled by the actuator 30A, the movable pin 63 moves to the end of the long hole 61a, and is further pulled by the second cable 62, causing the rotating plate 18A to rotate about the shaft 17 and return to the neutral position. This activates the HST brake to apply braking.

[0100] According to the brake mechanism 1F of the construction vehicle of this embodiment described above, since it is equipped with the brake means 6Bf, the forward / reverse lever 16 can be automatically returned to neutral upon detection by the distance image sensor (obstacle detection device) 2, and the HST brake can be activated, so that a collision accident due to human error can be avoided with a simple structure.

[0101] In addition, the connecting plate 61 has a connecting fulcrum portion (connecting pin) 18c that is rotatably connected to the rotating plate 18A, and a long hole 61a through which the movable pin 63 of the second cable 62 slides, so that the rotating plate 18A and the second cable 62 can be connected with a simple configuration.

[0102] The end of the long hole 61a on the second cable 62 side may be locally formed as a fine hole. This allows the movable pin 63 to be guided by the fine hole of the long hole 61a and to easily move to the end, thereby improving the responsiveness of the brake.

[0103] [Eighth embodiment] Next, a brake mechanism 1G for a construction vehicle according to an eighth embodiment of the present invention will be described. As shown in Fig. 22, in the brake mechanism 1G for a construction vehicle according to the eighth embodiment, the brake means 6Bg is different from that of the first embodiment. In the eighth embodiment, the differences from the first embodiment will be mainly described.

[0104] 22 and 23, the brake means 6Bg includes an actuator 30, a link plate 31, a base member 32, a first link rod 33, and a second link rod 34. The brake means of the actuator 30 system is the same as that of the first embodiment.

[0105] The brake means 6Bg includes a rotating plate 18A, a connecting plate 61, a second cable 62, and an actuator 30A. As shown in Fig. 22, the brake means of the actuator 30A system is the same as that of the seventh embodiment.

[0106] According to the brake mechanism 1G of the construction vehicle of this embodiment, for example, when an obstacle G is detected by the distance image sensor 2 while reversing, the control device 3 outputs a brake signal to activate both the actuator 30 and the actuator 30A. This makes it possible to more reliably activate the HST brake by the mechanisms of both the actuator 30 system and the actuator 30A system.

[0107] [Ninth embodiment] Next, a brake mechanism 1H of a construction vehicle according to a ninth embodiment will be described. As shown in Fig. 24 and Fig. 25, the brake mechanism 1H according to the ninth embodiment is equipped with a brake means 6Bh, and is obtained by adding a brake by a brake pedal 15 (third cable 65) system to the seventh embodiment. The ninth embodiment will be described mainly with respect to the parts that differ from the seventh embodiment.

[0108] The brake means 6Bh includes a rotating plate 18A, a connecting plate 61, a second cable 62, and an actuator 30A. The brake mechanism for the second cable 62 is the same as that in the seventh embodiment.

[0109] 24 and 25, the braking means 6Bh includes a third cable 65, a rotating plate 71, and a brake pedal rod 51. The braking means 6Bh operates the HST brakes in both the second cable 62 system and the third cable 65 system based on the actuator 30A.

[0110] The third cable 65 is a cable that connects the actuator 30A and the rotating plate 71. The rotating plate 71 is a plate-like member having a substantially triangular shape. The rotating plate 71 includes a main body portion 71a, a fixed fulcrum portion 71b, a connecting fulcrum portion 71c, and a connecting fulcrum portion 71d. The fixed fulcrum portion 71b, the connecting fulcrum portion 71c, and the connecting fulcrum portion 71d are provided near each corner of the triangle of the main body portion 71a. The fixed fulcrum portion 71b is a portion that is rotatably fixed via a bracket BK that is connected to a part of the vehicle.

[0111] The connecting fulcrum 71c is a portion to which an end of the third cable 65 is connected by a pin connection. The connecting fulcrum 71d is a portion to which a front end of the brake pedal rod 51 is connected by a pin connection. The rear end of the brake pedal rod 51 is loosely fitted into the engagement pin 15e of the brake pedal 15 via the long hole 51a.

[0112] As in the first embodiment, the shaft 17 and the rotating plate 18A return to the neutral position when the brake pedal 15 is depressed, and the HST brake is activated to brake. At this time, since the elongated hole 51a is provided in the brake pedal 15, the engagement pin 15e moves within the elongated hole 51a. In other words, the rotating plate 71 does not rotate when the brake pedal 15 is depressed.

[0113] On the other hand, for example, when an obstacle G is detected by the distance image sensor 2 during reverse travel, the control device 3 outputs a brake signal to drive the actuator 30A. The brake operation of the second cable 62 system is the same as in the seventh embodiment. When the output shaft 30Aa is pulled by driving the actuator 30A, the rotating plate 71 rotates clockwise around the fixed fulcrum part 71b via the third cable 65.

[0114] As a result, the brake pedal rod 51 is pulled diagonally downward toward the front side, so that the brake pedal 15 rotates in the actuation direction of the brake pedal 15. This also activates the brake mechanism of the brake pedal 15 system, and the HST brake is actuated.

[0115] According to the ninth embodiment described above, a single actuator 30A can operate both the second cable 62 system and the third cable 65 (brake pedal 15) system, so that braking can be performed more reliably.

[0116] [Tenth embodiment] Next, a brake mechanism 1J for a construction vehicle according to a tenth embodiment will be described. First, a conventional forward / reverse lever and forward / reverse switching lever will be described. FIG. 26 is a schematic diagram showing the relationship between a conventional forward / reverse lever and a forward / reverse switching lever. As shown in FIG. 26, a conventional traveling pump P (see also FIG. 9) is equipped with a rectangular plate-shaped forward / reverse switching lever 80. The forward / reverse switching lever 80 is a lever that switches the flow direction of pressure oil (hydraulic oil) in the traveling pump P.

[0117] The forward / reverse switching lever 80 has a fixed fulcrum portion 80a provided at an end portion and a connecting fulcrum portion 80b provided at the center portion. The connecting fulcrum portion 80b is connected to the first cable 19 by pin support. The first cable 19 connects the connecting fulcrum portion 80b of the forward / reverse switching lever 80 to the connecting fulcrum portion 18b of the rotating plate 18. The forward / reverse switching lever 80 can be rotated about the fixed fulcrum portion 80a by pushing and pulling the first cable 19. More specifically, the forward / reverse switching lever 80 can be rotated by a predetermined angle clockwise and counterclockwise from a neutral position (for example, the 12 o'clock position).

[0118] When the operator tilts the forward / reverse lever 16 forward (forward), the first cable 19 is pulled, and the forward / reverse switching lever 80 rotates clockwise around the fixed fulcrum 80a. This causes the pressure oil of the traveling pump P to flow to one side.

[0119] When the operator tilts the forward / reverse lever 16 backward (reverse), the first cable 19 is pushed, and the forward / reverse switching lever 80 rotates counterclockwise around the fixed fulcrum 80a. This causes the pressure oil of the traveling pump P to flow to the other side.

[0120] When the operator returns the forward / reverse lever 16 to the neutral position, the forward / reverse switching lever 80 is also in the neutral position. As a result, as shown in Fig. 9, no pressure difference occurs between the oil passage T1 and the oil passage T2, the swash plate is in the neutral position, and the HST (Hydro Static Transmission) brake is applied in the closed circuit U1.

[0121] Fig. 27 is a schematic diagram of a brake mechanism for a construction vehicle according to a tenth embodiment of the present invention. As shown in Fig. 27, in a brake mechanism 1J for a construction vehicle according to the tenth embodiment, a brake means 6Bi is different from that of the first embodiment. In the tenth embodiment, the differences from the first embodiment will be mainly described.

[0122] The brake means 6Bi includes a forward / reverse switching lever 81, a second cable 82, and an actuator 30A. The forward / reverse switching lever 81 is a lever that switches the flow direction of pressure oil in the traveling pump P. The forward / reverse switching lever 81 is connected to the first cable 19 via a connection fulcrum portion 81f. The connection fulcrum portion 81f and the fixed fulcrum portion 81g are spaced apart by a predetermined distance. The forward / reverse switching lever 81 can be rotated by a predetermined angle around the fixed fulcrum portion 81g by pushing and pulling the first cable 19.

[0123] The forward / reverse switching lever 81 includes a main body 81a, a first notch 81b, and a second notch 81c. The first notch 81b is formed in a generally arcuate shape so as to be convex toward the top of the drawing (the opposite side of the first notch 81b from the connecting fulcrum 81f). The second notch 81c is formed in the center of the first notch 81b and continues to the first notch 81b. The second notch 81c is formed in a generally semicircular shape so as to be convex toward the top of the drawing (the side away from the fixed fulcrum 81g that serves as the rotation center). The first notch 81b has a sufficiently large opening relative to the second notch 81c.

[0124] An engagement jig 42 is formed on the end of the second cable 82. The engagement jig 42 is a member that connects the forward / reverse switch lever 81 and the second cable 82, and in this embodiment, a clevis is used. The engagement jig 42 uses the same member as in the third embodiment.

[0125] Here, a position distant by a distance h1 from the axis of the fixed fulcrum portion 81g upward in the drawing (the opposite side of the fixed fulcrum portion 81g with respect to the first cutout hole 81b) is defined as a setback center C2. The radius from the axis of the fixed fulcrum portion 81g to the inner edge 81d of the first cutout hole 81b is defined as a radius r1. The radius from the axis of the fixed fulcrum portion 81g to the axis of the connector 42b is defined as a radius r2. The radius from the setback center C2 to the outer edge 81e of the first cutout hole 81b is defined as a radius r3.

[0126] In the initial position (when the forward / reverse lever 16 and the forward / reverse switching lever 81 are in the neutral position), as shown in Fig. 27, the connector (movable pin) 42b of the engagement jig 42 is located approximately in the center of the first notch 81b. When the forward / reverse lever 16 is switched to the forward position or the reverse position, the first cable 19 is pushed or pulled accordingly, causing the forward / reverse switching lever 81 to rotate around the fixed fulcrum portion 81g. At this time, since the first notch 81b is formed, there is no interference between the forward / reverse switching lever 81 and the engagement jig 42, allowing the forward / reverse switching lever 81 to rotate.

[0127] On the other hand, for example, when an obstacle G is detected by the distance image sensor 2 during reverse travel, the control device 3 outputs a brake signal to drive the actuator 30A. When the output shaft 30Aa of the actuator 30A is pulled, the second cable 82 is also pulled upward in the drawing (the opposite side of the coupling fulcrum 81f with respect to the engagement jig 42). As a result, the tilted forward / reverse travel switching lever 81 engages with the second notch hole 81c while the connector 42b slides on the outer edge 81e of the first notch hole 81b. Furthermore, the second notch hole 81c is pulled by the engagement jig 42, and the forward / reverse travel switching lever 81 is positioned in the neutral position. As a result, the HST (Hydro Static Transmission) brake acts in the closed circuit U1 (see FIG. 9).

[0128] When the actuator 30A is actuated by the detection, the first cable 19 is pushed or pulled by the forward / reverse switching lever 81, so that the rotating plate 18 and the forward / reverse lever 16 are also returned to the neutral position. When the output shaft 30Aa of the actuator 30A is returned to its original position, the second cable 82 is pushed, and the connector 42b of the engagement jig 42 is also returned to its original position.

[0129] According to the tenth embodiment described above, the forward / reverse switching lever 81 can be returned to the neutral position by detection of the distance image sensor (obstacle detection device) 2 without the operation of the operator. This activates the HST brake, making it possible to avoid collision accidents due to human error with a simple structure.

[0130] Furthermore, the shape of the forward / reverse switching lever 81 may be set as appropriate, but it is preferable that the forward / reverse switching lever 81 has a second notch hole 81c that is continuous with the first notch hole 81b, as in this embodiment. When the actuator 30A is actuated, the inclination of the forward / reverse switching lever 81 can be reliably returned to neutral by pulling the second cable 82 engaged in the second notch hole 81c. In other words, by providing the second notch hole 81c, the second cable 82 and the second notch hole 81c can be suitably engaged with each other, and the brake can be actuated more reliably.

[0131] 28 and 29 are enlarged views of a forward / reverse switching lever according to a modified example of the tenth embodiment. As shown in FIG. 28, the second cutout hole 81c may be omitted. In this modified example, the outer edge 81e of the first cutout hole 81b is pulled by the connector 42b of the engagement jig 42, whereby the tilted forward / reverse switching lever 81 can be returned to the neutral position.

[0132] Also, as shown in Fig. 29, the shape of the second cutout hole 81c may be triangular. By providing the second cutout hole 81c that extends further outward than the outer edge 81e of the first cutout hole 81b as shown in Figs. 27 and 29, the connector 42b of the engagement jig 42 can be easily engaged, so that the force for returning to the neutral position and the force for maintaining the neutral position (while the actuator 30A is operating) can be increased.

[0133] The second cutout hole 81c is not limited to the above shape, and may have other shapes as long as it can be engaged with or disengaged from the connector 42b. In the present embodiment, the forward / reverse switching lever 81 is formed of one member, but it may be formed of multiple members. For example, a plate-shaped member may be connected to the existing forward / reverse switching lever 80 in FIG. 26 to form the forward / reverse switching lever 81. This allows easy modification using an existing product.

[0134] 27 to 29, the setback center C2 of radius r3 may be offset by a distance h1 from the axis of the fixed fulcrum portion 81g, or, although not specifically shown, the radii r1, r2, and r3 may be concentric circles (distance h1 is zero). The first cutout hole 81b (second cutout hole 81c) and radii r1, r2, r3 may be set appropriately so that when the forward / reverse lever 16 is tilted, the forward / reverse switch lever 81 is allowed to rotate without interfering with the engaging jig 42, and so that when the actuator 30A is activated, the engaging jig 42 can be pulled to return the tilted forward / reverse switch lever 81 to the neutral position.

[0135] As described above, even if the radii r1, r2, and r3 are concentric circles (the distance h1 is zero), this can be achieved if the second cutout hole 81c is sufficiently large. "Sufficiently large" means that the size and shape of the first cutout hole 81b and the second cutout hole 81c are determined so that when the forward / reverse switching lever 81 rotates to the maximum tilt angle to one side or the other, and the connector 42b is pulled, the connector 42b is positioned more outward from the center than the arc drawn by the radius r3.

[0136] [Eleventh embodiment] Next, a brake mechanism 1K for a construction vehicle according to an eleventh embodiment of the present invention will be described. As shown in Fig. 30, in the brake mechanism 1K for a construction vehicle according to the eleventh embodiment, the brake means 6Bj differs from that of the first embodiment. In the eleventh embodiment, the differences from the first embodiment will be mainly described.

[0137] The brake means 6Bj includes a forward / reverse switching lever 90, a second cable 82, and an actuator 30A. The forward / reverse switching lever 90 includes a first member 91 and a second member 92, both of which are plate-shaped. The first member 91 includes a fixed fulcrum portion 93 and a connecting fulcrum portion 94. The fixed fulcrum portion 93 is formed on one end side and is a fulcrum that serves as the center of rotation. The connecting fulcrum portion 94 is disposed spaced apart from the fixed fulcrum portion 93. The first cable 19 is connected to the connecting fulcrum portion 94 by pin support. The other end of the first member 91 and one end of the second member 92 are connected by the connecting fulcrum portion 95 so as to be capable of relative rotation.

[0138] An engagement jig 42 is formed at the end of the second cable 82. An elongated hole 92a is formed in the second member 92, and the engagement jig 42 is engaged with the elongated hole 92a. The engagement jig 42 is a member that connects the second member 92 and the second cable 82, and in this embodiment, a clevis is used. A connection tool (movable pin) 42b is connected so as to be movable within the elongated hole 92a. The engagement jig 42 uses a member similar to that of the third embodiment.

[0139] When the forward / reverse switching lever 90 is in the neutral position, the first member 91 and the second member 92 are both located at the 12 o'clock position, for example.

[0140] In the initial position (when the forward / reverse lever 16 and the forward / reverse switch lever 90 are in the neutral position), the connector 42b of the engagement jig 42 is located approximately in the center of the elongated hole 92a, as shown in Fig. 30. When the forward / reverse lever 16 is switched to the forward position, the first cable 19 is pulled accordingly, and the first member 91 rotates clockwise around the fixed fulcrum portion 93, as shown in Fig. 31. At this time, the second member 92 is also tilted obliquely by being pulled by the first member 91, but since the connector 42b slides inside the elongated hole 92a, there is no effect on the second cable 82.

[0141] On the other hand, for example, when forward / reverse lever 16 is switched to the reverse position, as shown in Fig. 32, first cable 19 accordingly pushes first member 91, causing first member 91 to rotate counterclockwise around fixed fulcrum portion 93. At this time, second member 92 is also pulled by first member 91 and tilts obliquely, but since connector 42b slides within elongated hole 92a, second cable 82 is not affected.

[0142] On the other hand, for example, when an obstacle G is detected by the distance image sensor 2 while the vehicle is moving backward, the control device 3 outputs a brake signal to drive the actuator 30A. When the output shaft 30Aa of the actuator 30A is pulled, the second cable 82 is also pulled upward in the drawing (in the direction in which the second member 92 moves away from the first member 91) as shown in Fig. 33. As a result, the tilted first member 91 and second member 92 are pulled by the engagement jig 42, and the forward / reverse switching lever 90 is returned to the neutral position. As a result, the HST (Hydro Static Transmission) brake is applied in the closed circuit U1 (see Fig. 9).

[0143] When the actuator 30A is actuated by the detection, the first cable 19 is pushed or pulled by the first member 91, so that the rotating plate 18 and the forward / reverse lever 16 are also returned to the neutral position. When the output shaft 30Aa of the actuator 30A is returned to its original position, the second cable 82 is pushed, and the connector 42b of the engagement jig 42 is also returned to its original position.

[0144] According to the eleventh embodiment described above, the forward / reverse switching lever 90 can be returned to the neutral position by detection of the distance image sensor (obstacle detection device) 2 without the operation of the operator. This activates the HST brake, making it possible to avoid collision accidents due to human error with a simple structure.

[0145] Furthermore, the forward / reverse switching lever 90 may be set as appropriate, but as in this embodiment, it can be simply configured with a first member 91 and a second member 92. For example, the existing forward / reverse switching lever 80 in Fig. 26 may be used as the first member 91, and the second member 92 may be connected to the first member 91. This allows easy modification using an existing product.

[0146] Although the embodiment and the modified examples of the present invention have been described above, appropriate design modifications are possible. One embodiment may also be applied in combination with another embodiment or modified example. [Explanation of symbols]

[0147] 1 Brake mechanism for construction vehicles 2. Distance image sensor (obstacle detection device) 3 Control device (control unit) 4. Detection range 6,6A,6B Braking means 7 Vehicle speed sensor 10. Roller (construction vehicle) 15 Brake pedal 16 Forward / reverse lever 17 Shaft 19 First Cable 22 Base plate 30 Actuator 30A Actuator 32 Base material 62 Second Cable 65 Third Cable 81 Forward / reverse switch lever 81b First hole 81c Second notch hole 82 Second Cable 90 Forward / reverse switch lever 91 First member 92 Second member 92a long hole G Obstacle P Travel pump

Claims

1. An obstacle detection device that detects obstacles around the construction vehicle; a shaft that rotates about its axis in response to tilting of the forward / reverse lever; a first cable connecting a rotating plate fixed to the shaft and a forward / reverse switching lever of a traveling pump that causes the construction vehicle to travel; An actuator provided on the construction vehicle; a second cable connecting the forward / reverse switching lever and the actuator; a control unit that, when an obstacle is detected by the obstacle detection device, activates the actuator and returns the forward / reverse switch lever to neutral via the second cable, thereby activating the brakes.

2. The forward / reverse switching lever has a first notch that allows the forward / reverse switching lever to rotate when the forward / reverse switching lever is tilted, 2. A brake mechanism for a construction vehicle according to claim 1, wherein when the actuator is actuated, the forward / reverse switching lever is returned to neutral by pulling the forward / reverse switching lever through the first notch.

3. The forward / reverse switching lever has a second notch hole that is continuous with the first notch hole and extends away from the rotation center of the forward / reverse switching lever, The brake mechanism for a construction vehicle as described in claim 2, characterized in that when the actuator is activated, the second cable engaged in the second recess is pulled to return the inclination of the forward / reverse switching lever to neutral.

4. The forward / reverse switching lever is configured such that the other end of the first member and one end of the second member are connected to each other at a connecting fulcrum portion so as to be rotatable relative to each other, the first member includes a fixed fulcrum portion provided on one end side and serving as a rotation center, and a connecting fulcrum portion provided apart from the fixed fulcrum portion and to which the first cable is connected, The brake mechanism for a construction vehicle as described in claim 1, characterized in that the second member has a long hole extending in the longitudinal direction, and a movable pin provided at the tip of the second cable and movably connected to the long hole.

Images