JP6024965B2 - Dump truck movable bumper - Google Patents

Description

  The present invention relates to a movable bumper that is set at the rear of a dump truck having a function of tilting a loading platform toward the rear of the vehicle.

  Generally, a fixed bumper is set at the rear end position of a pair of side frames of a truck. However, in the case of a dump truck, the rear end of a pair of side frames is mainly intended to avoid interference with a tilting loading platform. The bumper main body is set so as to be rotatable through the bumper arm at the part position. As this movable bumper, the bumper usage position is set as the rear end lower position of the side frame, and the vehicle front side lower position protruding downward from the side frame is turned to the vehicle front side from the bumper usage position. A bumper storage position is known (see, for example, FIG. 7 of Patent Document 1).

JP 2011-80511 A

However, in the conventional movable bumper, the bumper body and the bumper arm protrude downward from the side frame in the bumper storage position. For this reason, the space from the ground to the bumper body is limited at the bumper storage position.For example, when the movable bumper is stored and the asphalt finisher is inserted into the lower space of the side frame from the rear of the vehicle, it interferes with the bumper body. There was a problem of fear.
In addition, at the bumper storage position, the bumper arm is rotated downward by its own weight. For this reason, there is a problem that an arm fixing operation for fixing the bumper arm with the pin while supporting the bumper arm at the bumper storage position is required, and the burden of the bumper storage operation is increased.

  The present invention has been made paying attention to the above problem, and at the bumper storage position, it is possible to achieve both the prevention of interference with the inclined cargo bed, the securing of the space from the ground, and the reduction of the bumper storage operation burden. An object is to provide a movable bumper for a dump truck.

To achieve the above object, the present invention provides a pair of bumper arms that are axially supported by a pair of side frames that extend in the vehicle longitudinal direction, and a bumper body that is integrally fixed to the pair of bumper arms and extends in the vehicle width direction. Assuming that
In this dump truck movable bumper,
The pair of bumper arms and the bumper body are provided so as to be rotatable between a bumper use position and a bumper storage position,
The bumper use position of the pair of bumper arms and the bumper body is set to a vehicle rear side lower position from the rear ends of the pair of side frames,
The bumper storage position of the pair of bumper arms and the bumper body is defined as an arrival position that is rotated from the bumper use position to the vehicle upper side to reach.
And, the reach position is a vehicle front side position from the maximum inclined load platform line at the time of the maximum tilt of the load platform, and the bumper body exceeds the support shaft vertical line passing through the arm support shaft to the vehicle front side, Set the lower surface of the bumper stay to a position that defines the ground clearance ,
The bumper stay is L-shaped by a frame fixing portion extending in the vehicle vertical direction and a vehicle rearward extending portion extending rearward from the frame fixing portion,
The reaching positions of the pair of bumper arms and the bumper body are stored in an L-shaped recess formed by the bumper stay, and set to a position where the weight is supported by the upper surface of the vehicle rearward extension portion. To do.

As described above, the bumper storage position was set to a position that does not interfere with the assumption of the loading platform having the maximum inclination angle. For this reason, at the time of unloading work by stopping and tilting the loading platform, interference between the loading platform tilted at various angles and the bumper body is prevented.
As described above, the bumper storage position is set at a position where the bumper body exceeds the support shaft vertical line passing through the arm support shaft to the front side of the vehicle. For this reason, in the bumper storage position, the arm can be stored by the weight of the bumper body and the bumper arm without requiring an arm fixing operation, and the burden of the bumper storage operation is reduced.
As described above, the bumper storage position is set to a position where the lower surface of the bumper stay defines the ground clearance. For this reason, a space from the ground to the lower surface of the bumper stay is ensured without the space from the ground being restricted by the bumper body at the bumper storage position.
In this way, the bumper arm and the bumper body can be stored in the bumper stay with space efficiency and with its own weight, so that at the bumper storage position, it prevents interference with the inclined loading platform, secures space from the ground, and performs bumper storage operations. A reduction in burden can be achieved together.
In addition, since the bumper stay has an L-shaped configuration, the bumper arm and the bumper main body can be stored with high storage capacity and can be reliably supported by its own weight.

It is a whole side view showing an example of a dump truck with an air suspension to which the movable bumper of Example 1 is applied. It is a truck rear view which shows the bumper use position of a pair of bumper arm and a bumper main body in the movable bumper of the dump truck with an air suspension of Example 1. It is a truck rear view which shows the bumper storing position of a pair of bumper arm and a bumper main part in the movable bumper of the dump truck with an air suspension of Example 1. It is an enlarged side view which shows the movable bumper of the dump truck with an air suspension of Example 1. FIG. It is a disassembled perspective view which shows the bumper stay, bumper arm, bumper main body, and arm spindle which are the components of the movable bumper of Example 1. FIG. FIG. 6 is an operation explanatory diagram for explaining a movement operation of the locking arm from the arm lock position to the arm lock release position at the bumper use position in the first embodiment. FIG. 10 is an operation explanatory diagram for explaining a rotation operation of the bumper arm from the bumper use position toward the bumper storage position in the unlocked state in the first embodiment. FIG. 5 is an operation explanatory diagram illustrating a self-weight support operation of a bumper arm and a bumper body at a bumper storage position in the first embodiment. It is an operation explanatory view explaining the setting position height adjustment operation of the movable bumper of the first embodiment.

  Hereinafter, the best mode for realizing the movable bumper of the dump truck of the present invention will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
The configuration of the movable bumper of the dump truck with an air suspension (an example of the dump truck) in the first embodiment will be described by being divided into “overall configuration”, “main configuration of movable bumper”, and “detailed configuration of movable bumper components”.

[overall structure]
FIG. 1 is an overall side view showing an example of a dump truck with an air suspension to which the movable bumper of Example 1 is applied, FIG. 2 shows a bumper use position, and FIG. 3 shows a bumper storage position. Hereinafter, the overall configuration will be described with reference to FIGS.

  As shown in FIG. 1, the dump truck with an air suspension to which the movable bumper A1 of the first embodiment is applied includes an occupant cabin 1, a side frame 2, a subframe 3, a load carrier 4, a front wheel 5, and a rear wheel 6. The front bumper 7, the loading platform tilting support shaft 8, and the air suspension 9 are provided.

  As shown in FIG. 1, the loading platform 4 is provided so as to be tiltable to the position of the maximum inclined loading platform line Lmax by turning the vehicle rearward about the loading platform tilting support shaft 8 with respect to the subframe 3. Yes.

  As shown in FIG. 1, the front wheel 5 and the rear wheel 6 are suspended by a pair of side frames 2 extending in the vehicle front-rear direction by an air suspension 9. The side frames 2 are supported by the air suspension 9 having the air spring structure, so that, for example, the vehicle height is higher than that of a dump spring having a leaf spring suspension type, and the vehicle height can be freely adjusted.

  As shown in FIG. 1, the front bumper 7 has a fixed bumper configuration fixed to the front portion of the vehicle, and the movable bumper A <b> 1 is set as a rear bumper at the rear of the vehicle with respect to the front bumper 7.

  The movable bumper A1 is configured to be rotatable by a manual operation between a bumper use position shown in FIG. 2 and a bumper storage position shown in FIG. As shown in FIGS. 2 and 3, the movable bumper A <b> 1 includes a pair of bumper stays 10, a pair of bumper arms 11, and a bumper body 12.

  The pair of bumper stays 10 extends in the vehicle front-rear direction and is fastened and fixed to the pair of side frames 2 connected by the cross frame 30. The pair of bumper arms 11 are axially supported so as to be rotatable with respect to the pair of bumper stays 10, respectively. The bumper body 12 is integrally bolted to the pair of bumper arms 11 and extends in the vehicle width direction.

  As shown in FIG. 2, the bumper use positions of the pair of bumper arms 11 and the bumper main body 12 are set to the rear end lower positions of the pair of side frames 2 based on the safety standards of the Road Transport Vehicle Law.

The bumper storage positions of the pair of bumper arms 11 and the bumper body 12 are rotated from the bumper use position indicated by the phantom line in FIG. To reach the position.
2 and 3, reference numeral 31 denotes a guard plate that is fixed to the sub-frames 3 and 3 and is disposed at an upper position on the rear side of the rear wheel 6. A cross frame 32 connects the pair of subframes 3 in the vehicle width direction.

[Main parts of movable bumper]
FIG. 4 is an enlarged side view illustrating the movable bumper A1 according to the first embodiment. Hereinafter, the main configuration of the movable bumper A1 will be described with reference to FIG.

  As shown in FIG. 4, the movable bumper A <b> 1 includes a side frame 2, a bumper stay 10, a bumper arm 11, a bumper body 12, and an arm support shaft 13 as shown in FIG. 4.

  The bumper arm 11 and the bumper body 12 can be rotated between a bumper use position (solid line position in FIG. 4) and a bumper storage position (virtual line position in FIG. 4) around an arm support shaft 13 with respect to the bumper stay 10. Is provided.

Bumper use positions of the bumper arm 11 and the bumper main body 12 are set to the lower position of the rear end of the side frame 2 defined based on the safety standards of the Road Transport Vehicle Law, as shown by the solid line position in FIG. . Specifically, the height H from the ground to the bumper body 12 is about 450 mm (<specified dimension 550 mm), and the longitudinal dimension D from the rear end position of the loading platform 4 to the bumper body 12 is about 150 mm (<specified dimension). 400mm).
In other words, the movable bumper A1 as the rear bumper has a height H from the ground and a rear end of the loading platform in order to prevent a phenomenon called submarine where a passenger car or the like dives under an accident such as a rear-end collision when the bumper is used. The front-rear dimension D is severely limited.

  The bumper storage position of the bumper arm 11 and the bumper main body 12 is a vehicle front side position relative to the maximum inclined load carrier line Lmax when the load carrier 4 is at the maximum inclination as shown by the phantom line in FIG. The lower side 10a of the bumper stay 10 is set to a position that defines the ground clearance at the bumper storage position, as well as to the vehicle front side from the vertical axis Lper that passes through the arm support shaft 13.

  The bumper stay 10 is L-shaped by a frame fixing portion 10b extending in the vehicle vertical direction and a vehicle rearward extending portion 10c extending rearward from the frame fixing portion 10b. And the reach | attainment position of the bumper arm 11 and the bumper main body 12 is accommodated in the L-shaped recessed part 10d formed by the L-shaped bumper stay 10, and it is the position supported by the upper surface 10e of the vehicle rear extension part 10c by its own weight. It is set (see FIG. 8).

[Detailed configuration of movable bumper components]
FIG. 5 is an exploded perspective view showing the bumper stay 10, the bumper arm 11, the bumper main body 12, and the arm support shaft 13 which are components of the movable bumper A <b> 1. Hereinafter, based on FIG. 5, the detailed structure of a movable bumper component is demonstrated.

  As shown in FIG. 5, the movable bumper A1 according to the first embodiment includes a bumper stay 10, a bumper arm 11, a bumper main body 12, an arm support shaft 13, a locking arm 14, a stopper pin 15, and a support shaft. 16, a spring 17, and a manual operation lever 18.

  The bumper stay 10 is made of high-strength steel and is firmly fixed to the side frame 2 by four bolts and nuts 19 (FIG. 4), and supports the bumper arm 11 so as to be rotatable. It is a component. The bumper stay 10 is provided with an arm support hole 10h through which the arm support shaft 13 is inserted, and has a stay side stopper plate 10f at a position in front of the vehicle with the arm support shaft 13 interposed therebetween. A stay side stopper recess 10g is provided at the rear position. Further, the bumper stay 10 is provided with a stay side bolt hole 10 i that communicates with a frame side bolt hole 2 a provided in the side frame 2 and is fastened and fixed by a bolt / nut 19.

  The bumper stay 10 is fixed to the side frame 2 through a set position height adjustment structure of the movable bumper A1. In this setting position height adjustment structure, when the fixing position of the bumper stay 10 is changed in the height direction, the communication between the frame side bolt hole 2a and the stay side bolt hole 10i is before or after the change. The positions of both bolt holes 2a and 10i are set so as to be secured. In other words, the stay side bolt holes 10i are provided in a total of 9 rows in 3 rows and 3 rows in a row, while the frame side bolt holes 2a are similarly provided in a total of 9 rows in 3 rows and 3 rows. The vertical span and horizontal span, which are the intervals, are the same span. Of the three bolt rows 2a and 10i in the vertical row, the central row is a spare hole used as necessary to increase the fixing strength.

  The bumper arm 11 is made of high-strength steel and is a component that is pivotally supported on the bumper stay 10 via an arm support shaft 13 and to which the bumper body 12 is fastened and fixed. . The bumper arm 11 connects two arm plates 11a having the same shape with an arm side stopper plate 11b on the front side of the vehicle via a space where the bumper stay 10 can be inserted, and a bumper fixing plate 11c on the rear side of the vehicle. Are connected. The two arm plates 11a are provided with arm support shaft holes 11d through which the arm support shafts 13 are inserted. A bumper main body 12 having a stud bolt having a square cross section is fastened and fixed to the bumper fixing plate 11c.

  The arm support shaft 13 is made of high-tensile steel and has a stopper ring 13a on one end side and a split pin hole 13b on the other end side. Then, the bumper stay 10 is inserted between the two arm plates 11a, and is inserted into the arm support shaft hole 10h of the bumper stay 10 and the arm support shaft hole 11d of the bumper arm 11 from one end side, and a split pin (not shown) is used. It is prevented from coming off.

  The locking arm 14 is made of high-strength steel and is interposed between the two arm plates 11a. At the same time, the arm lock position and the arm lock are released by the support shaft 16 with respect to the two arm plates 11a. It is supported so as to be able to turn upward between the positions. The locking arm 14 is fixed in parallel with the stopper pin 15, a stopper pin 15 fixed to the upper end of the arm, a spring 17 interposed between the stopper pin 15 and the arm plate 11a, and the stopper pin 15. And a manual operation lever 18 extending toward.

  The spring 17 is set to apply an urging force to the stopper pin 15 in the contact direction (front direction of the vehicle) at an arm lock position where the stopper pin 15 is fitted and brought into contact with the stay side stopper recess 10g (FIG. 4). At the same time, an urging force is applied to the stopper pin 15 in the releasing direction (rear direction of the vehicle) at the arm lock releasing position where the stopper pin 15 is removed from the stay side stopper recess 10g (FIG. 6). That is, the spring 17 is arranged in the vehicle front direction with respect to the support shaft 16 at the arm lock position, the spring 17 and the support shaft 16 coincide with each other at the intermediate position, and the spring 17 is behind the support shaft 16 with respect to the arm lock release position. It is set to be placed in.

  A pair of left and right manual operation levers 18 are provided to the locking arm 14 so as to extend toward the vehicle central axis (see FIG. 2). In other words, the pair of left and right manual operation levers 18 are manual operation means that are set to positions where an operator standing in the center position of the bumper body 12 can easily hold with the left and right hands, and the arm lock position at the bumper use position. The operation of moving the locking arm 14 between the bumper arm 11 and the arm lock release position and the operation of rotating the bumper arm 11 between the bumper use position and the bumper storage position in the unlocked state are performed.

  Between the bumper stay 10 and the bumper arm 11, an arm lock structure for fixing the arm operation of the bumper arm 11 at the bumper use position is provided. This arm lock structure restricts rotation in the vehicle front direction when the arm side stopper plate 11b provided on the bumper arm 11 comes into contact with the stay side stopper plate 10f by its own weight at the bumper use position. In this vehicle forward rotation restricted state, the stopper pin 15 provided at the end of the locking arm 14 is fitted and brought into contact with the stay-side stopper recess 10g to restrict the vehicle rearward rotation. In other words, the bumper arm 11 is fixed at the bumper use position by restricting the rotation in the vehicle longitudinal direction. In addition, there is no arm lock structure in the bumper storage position, and it is only supported by its own weight on the upper surface 10e of the vehicle rearward extension 10c of the bumper stay 10.

Next, the operation will be described.
The action of the movable bumper A1 of the dump truck with air suspension according to the first embodiment will be described by dividing it into “an action when the bumper is used”, “an action when the bumper is stored”, and “an adjustment operation for the set position of the movable bumper”.

[Operation when using bumper]
In the bumper use position, it is necessary that the arm lock operation and the arm lock release operation of the bumper arm 11 be easy. Hereinafter, based on FIG.4 and FIG.6, the effect | action at the time of bumper use which reflects this is demonstrated.

When the arm operation of the bumper arm 11 is fixed at the bumper use position, as shown in FIG. 4, the arm side stopper plate 11b provided on the bumper arm 11 makes its own weight contact with the stay side stopper plate 10f at the bumper use position. As a result, rotation in the forward direction of the vehicle is restricted. That is, the force due to the weight of the bumper arm 11 and the bumper main body 12 together is the contact force between the stopper plates 10f and 11b.
Then, in a state of restricting rotation in the front direction of the vehicle, the pair of left and right manual operation levers 18 are grasped and pushed forward of the vehicle, and as shown in FIG. The stopper pin 15 provided on is fitted and brought into contact. This arm fixing operation restricts the rearward rotation of the vehicle. That is, the bumper arm 11 is fixed at the bumper use position by restricting the rotation in the vehicle front-rear direction.

  When the vehicle travels in a fixed state at this bumper use position, it is necessary to keep the arm operation fixed even with respect to the vibration input applied to the stopper pin 15. As a countermeasure against this vibration input, in the first embodiment, the biasing force is applied to the stopper pin 15 by the spring 17 in the fixing direction (front direction of the vehicle) at the arm lock position. For this reason, unless excessive vibration input that exceeds the biasing force or contact friction force in the direction of removing the stopper pin 15 is applied, the arm operation is fixed with respect to the vibration input applied during normal traveling including a rough road. Is done.

Next, when releasing the fixation of the bumper arm 11 at the bumper use position, the pair of left and right manual operation levers 18 are grasped and pulled toward the vehicle rear side as indicated by an arrow C in FIG. The stopper pin 15 fitted and contacted is removed. The bumper arm 11 is released by this arm release operation.
In this fixed release state of the bumper arm 11, it is necessary to maintain the locking arm 14 at the fixed release position so as not to return to the original fixed side. As a measure for maintaining the release position, in the first embodiment, the biasing force is applied to the stopper pin 15 by the spring 17 in the release direction (rear direction of the vehicle) at the arm lock position. For this reason, even if the hand is released from the pair of left and right manual operation levers 18, the fixed release state of the bumper arm 11 is maintained as it is by the biasing force of the spring 17.

[Bumper storage action]
In the bumper storage position of the movable bumper A1, in order to perform various operations including the inclination of the loading platform 4, it is necessary to store the movable bumper A1 in a space efficient position that does not interfere with the operation as much as possible. It is also necessary to reduce the storage operation burden. Hereinafter, based on FIG.7 and FIG.8, the effect | action at the time of bumper accommodation reflecting this is demonstrated.

  When performing a rotation operation from the bumper use position state (FIG. 6) to the bumper storage position, the pair of left and right manual operation levers 18 are gripped and lifted upward, and the bumper arm 11 and the bumper are centered on the arm support shaft 13. The main body 12 is rotated. At this time, a lifting force is required for the manual operation lever 18 until the bumper arm 11 and the bumper body 12 reach the vertical upper position indicated by the arrow E in FIG. 7, but when the vertical upper position is exceeded, FIG. As shown by the arrow F, the bumper arm 11 and the bumper body 12 rotate toward the bumper storage position due to their own weight. In the bumper storage position, as shown in FIG. 8, the bumper arm 11 and the bumper main body 12 are supported by their own weight on the upper surface 10 e of the vehicle rearward extension 10 c of the bumper stay 10. The bumper arm 11 and the bumper main body 12 are set at the bumper storage position only when the vehicle is stopped. Therefore, it is not necessary to fix the bumper arm 11 and the bumper main body 12 at the bumper storage position.

In Example 1, the bumper storage position was set to a position that does not interfere with the assumption that the loading platform 4 having the maximum inclination angle Lmax is used. For this reason, at the time of unloading work by stopping and tilting the loading platform 4, interference between the loading platform 4 tilted at various angles and the bumper body 12 is prevented.
The bumper storage position is set to a position where the bumper body 12 exceeds the support shaft vertical line Lper passing through the arm support shaft 13 toward the front side of the vehicle. For this reason, in the bumper storage position, it is possible to store the bumper by the weight of the bumper body 12 and the bumper arm 11 without requiring an arm fixing operation, thereby reducing the burden of the bumper storage operation.
Furthermore, the bumper storage position is set to a position where the lower surface 10a of the bumper stay 10 defines the ground height. For this reason, the space from the ground to the lower surface 10a of the bumper stay 10 is ensured without the space from the ground being limited by the bumper body 12 at the bumper storage position.
In this way, the bumper arm 11 and the bumper main body 12 can be stored in the bumper stay 10 with space efficiency and with its own weight, thereby preventing “interference with the inclined loading platform” and “from the ground” at the bumper storage position. Secure space and “relieve the burden of bumper storage”.

  On the other hand, when the rotation operation from the bumper storage position state (FIG. 8) to the bumper use position is performed, the bumper body 12 or the pair of left and right manual operation levers 18 are gripped and pulled back to the rear of the vehicle. The bumper arm 11 and the bumper body 12 are rotated in the opposite directions. At this time, until the bumper arm 11 and the bumper main body 12 reach the vertical upper position shown in FIG. 7, a pulling force is required for the manual operation lever 18, but when the vertical upper position is exceeded, the bumper arm 11 and the bumper The main body 12 rotates toward the bumper use position by its own weight. Then, at the bumper use position, as shown in FIG. 6, the rotation is restricted by the arm side stopper plate 11b provided on the bumper arm 11 coming into contact with the stay side stopper plate 10f by its own weight.

[Moving bumper set position height adjustment]
The height of the movable bumper A1 from the ground at the bumper use position is strictly regulated. For this reason, when applied to a dump truck with an air suspension, or when the same movable bumper unit is applied to different vehicle types, it is useful to provide a function for adjusting the set position height of the movable bumper A1. Hereinafter, based on FIG.4 and FIG.9, the setting position height adjustment effect | action of movable bumper A1 reflecting this is demonstrated.

  When the movable bumper A1 is set to a normal height, as shown in FIG. 4, the bumper stay 10 is set so that all nine of the frame side bolt holes 2a communicate with nine of the stay side bolt holes 10i. To do. Then, among the nine communicating bolt holes 2a and 10i, bolts are inserted into the four communicating bolt holes 2a and 10i at the corners, and fastened and fixed to the side frame 2 with nuts.

  On the other hand, when the movable bumper A1 is set at a lower height than usual, as shown in FIG. 9, among the nine stay side bolt holes 10i, the frame side bolt holes 2a 9 The bumper stay 10 is set so that the upper six pieces communicate with each other. Then, among the six bolt holes 2a and 10i communicating with each other, the bolts are inserted into the four bolt holes 2a and 10i communicating at the corners, and are fastened and fixed to the side frame 2 with nuts.

  Accordingly, as shown in FIG. 9, the movable bumper A1 can be set with the adjustment height ΔH lower than the normal position setting of the movable bumper A1 shown in FIG. When the movable bumper A1 is applied to a dump truck with an air suspension as in the first embodiment, the height adjustment function of the movable bumper A1 is increased by the vehicle height adjustment function of the air suspension 9, and the ground height is increased. This is useful when the ground clearance from the distance is outside the regulatory level. Further, when the movable bumper A1 is applied to vehicle types having different vehicle heights, it is possible to provide compatibility with vehicle types having different vehicle heights simply by preparing the same movable bumper unit.

Next, the effect will be described.
In the movable bumper A1 of the dump truck with air suspension of the first embodiment, the effects listed below can be obtained.

(1) A bumper stay 10 fixed to a rear end position of the pair of side frames 2 extending in the vehicle front-rear direction, a pair of bumper arms 11 rotatably supported on the bumper stay 10, and the pair In a movable bumper A1 of a dump truck (a dump truck with an air suspension) having a bumper body 12 that is integrally fixed to the bumper arm 11 and extends in the vehicle width direction,
The pair of bumper arms 11 and the bumper body 12 are provided so as to be rotatable between a bumper use position and a bumper storage position about an arm support shaft 13 with respect to the bumper stay 10;
The bumper use positions of the pair of bumper arms 11 and the bumper body 12 are set to the vehicle rear side lower position from the rear ends of the pair of side frames 2,
The bumper storage position of the pair of bumper arms 11 and the bumper body 12 is an arrival position that is reached by rotating the bumper from the bumper use position to the vehicle upper side,
The arrival position is a position on the vehicle front side from the maximum inclined load line Lmax when the load bed 4 is at the maximum inclination, and the bumper body 12 exceeds the support shaft vertical line Lper passing through the arm support shaft 13 to the vehicle front side. In addition, the lower surface 10a of the bumper stay 10 is set to a position that defines the ground height.
As described above, the bumper arm 11 and the bumper body 12 can be stored in the bumper stay 10 with space efficiency by its own weight. Therefore, in the bumper storage position, the interference with the inclined loading platform is prevented, and the space is secured from the ground. Reduction of the bumper storage operation burden can be achieved at the same time.

(2) The bumper stay 10 is L-shaped by a frame fixing portion 10b extending in the vehicle vertical direction and a vehicle rearward extending portion 10c extending from the frame fixing portion 10b to the vehicle rear side.
The reaching positions of the pair of bumper arms 11 and the bumper main body 12 are set to positions where they are housed in an L-shaped recess 10d formed by the bumper stay 10 and are supported by their own weight on the upper surface 10e of the vehicle rearward extension 10c. did.
Thus, since the bumper stay 10 has an L-shaped configuration, in addition to the effect of (1), the bumper arm 11 and the bumper body 12 can be stored with high storage capacity and can be reliably supported by their own weight.

(3) The bumper stay 10 has a stay side stopper plate 10f at a vehicle front position across the arm support shaft 13, and a stay side stopper recess 10g at a vehicle rear position across the arm support shaft 13. ,
The bumper arm 11 includes an arm-side stopper plate 11b at a position corresponding to the stay-side stopper plate 10f, and a locking arm 14 that is rotatably supported by a support shaft 16 with respect to the arm plate 11a. And
Provided between the bumper stay 10 and the bumper arm 11 is an arm lock structure for fixing the arm operation of the bumper arm 11 at a bumper use position,
The arm lock structure is provided at the end of the locking arm 14 in the stay-side stopper recess 10g in a state where the rotation of the stay-side stopper plate 10f and the arm-side stopper plate 11b in the forward direction of the vehicle is restricted. The stopper pin 15 is fitted into and brought into contact with the stopper pin 15 so as to restrict the rearward rotation of the vehicle.
As described above, since the arm lock structure that restricts the rotation in the vehicle front-rear direction is employed, in addition to the effect (1) or (2), the arm operation of the bumper arm 11 can be reliably fixed at the bumper use position. .

(4) The locking arm 14 includes a stopper pin 15 fixed to the upper end portion of the arm, and a spring 17 interposed between the stopper pin 15 and the arm plate 11a.
A biasing force is applied to the stopper pin 15 in the contact direction at an arm lock position where the stopper 17 is fitted and brought into contact with the stay-side stopper recess 10g, and the stopper pin 15 is moved to the stay-side stopper. The setting is such that an urging force is applied to the stopper pin 15 in the releasing direction at the arm lock releasing position removed from the recess 10g.
As described above, since the urging force is applied at two different positions while using one spring 17, in addition to the effect of (3), the arm fixing property at the arm lock position can be improved, and the arm Release maintainability at the lock release position can be improved.

(5) A pair of left and right manual operation levers 18 which are arranged in parallel with the stopper pin 15 and extend toward the vehicle central axis are fixed to the pair of locking arms 14,
The pair of left and right manual operation levers 18 are operated to move the locking arm 14 between the arm lock position and the arm lock release position at the bumper use position, and the bumper use position and the bumper storage position in the unlock state. Manual operation means for rotating the bumper arm 11 between the two.
As described above, since the necessary operations are performed together by grasping the pair of left and right manual operation levers 18, in addition to the effect of (4), the movement operation of the locking arm 14 and the rotation operation of the bumper arm 11 can be easily performed. In addition, it can be performed with good workability.

(6) The bumper stay 10 is provided with a stay side bolt hole 10i that is connected to the frame side bolt hole 2a provided in the side frame 2 and is fastened and fixed by a bolt / nut 19.
When the fixing position of the bumper stay 10 is changed in the height direction, the frame side bolt holes 2a and the frame side bolt holes 2a are secured so that the communication between both the bolt holes 2a and 10i is ensured before or after the change. The position of the stay side bolt hole 10i was set.
As described above, since the movable bumper A1 is configured to have the function of adjusting the set position height, the movable bumper A1 can be optimized without changing the unit design or replacing the unit in addition to the effects (1) to (5). Can be set to position. This set position height adjustment function is particularly useful when the movable bumper A1 is applied to a dump truck with an air suspension, or when the movable bumper A1 is applied to a vehicle type having a different vehicle height.

  As described above, the movable bumper of the dump truck according to the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the claims relate to each claim. Design changes and additions are allowed without departing from the scope of the invention.

  In the first embodiment, as the means for fixing the bumper arm 11 at the bumper use position and the bumper storage position, an example of means for restricting the rotation in the vehicle front-rear direction is shown. However, as a means for fixing the bumper arm at the bumper use position and the bumper storage position, an example using a fixing pin may be used. In other words, any other locking mechanism may be used as long as it can be reliably fixed to the bumper use position. As an example.

  In the first embodiment, an example in which the bumper body 12 has a square cross section is shown. However, the bumper body includes those having other shapes such as a circular cross section.

  In the first embodiment, an example in which the movable bumper A1 can be set and adjusted to a normal position and a position lower than the normal position is shown. However, if there is no structural obstacle, the movable bumper can be set and adjusted to a position higher than the normal position. In addition, as in Example 1, when three rows of bolt holes in the height direction are provided, the height position can be adjusted in three stages, but the number of rows of bolt holes in the height direction can be varied, It is also possible to adjust the height position in three or more stages by determining the communication combination.

  In Example 1, the example which applies movable bumper A1 to the dump truck with an air suspension was shown. However, the movable bumper of the present invention can of course be applied to a dump truck that is not suspended by an air suspension.

A1 Movable bumper 2 Side frame 2a Frame side bolt hole 4 Loading platform 10 Bumper stay 10a Lower surface 10b Frame fixing portion 10c Vehicle rearward extension portion 10d L-shaped recess 10e Upper surface 10f Stay side stopper plate 10g Stay side stopper recess 10i Stay side bolt hole 11 Bumper arm 11a Arm plate 11b Arm side stopper plate 12 Bumper body 13 Arm support shaft 14 Locking arm 15 Stopper pin 16 Support shaft 17 Spring 18 Manual operation lever 19 Bolt / Nut Lmax Maximum inclined load platform line Lper Support shaft vertical line ΔH Adjustment height The

Claims (5)

A bumper stay fixed to the rear end position of a pair of side frames extending in the longitudinal direction of the vehicle, a pair of bumper arms pivotally supported with respect to the bumper stay, and a pair of bumper arms fixed integrally to the pair of bumper arms A bumper movable bumper having a bumper body extending in the vehicle width direction,
The pair of bumper arms and the bumper body are provided so as to be rotatable between a bumper use position and a bumper storage position around an arm support shaft with respect to the bumper stay,
The bumper use position of the pair of bumper arms and the bumper body is set to a vehicle rear side lower position from the rear ends of the pair of side frames,
The bumper storage position of the pair of bumper arms and the bumper body is set as an arrival position that is reached by rotating the bumper from the bumper use position to the vehicle upper side,
The reach position is a vehicle front side position relative to the maximum inclined load bed line when the load bed is at the maximum inclination, and the bumper body exceeds the support shaft vertical line passing through the arm support shaft to the vehicle front side. Set the bottom surface of the to a position that defines the ground clearance ,
The bumper stay is L-shaped by a frame fixing portion extending in the vehicle vertical direction and a vehicle rearward extending portion extending rearward from the frame fixing portion,
The reaching positions of the pair of bumper arms and the bumper main body are stored in an L-shaped recess formed by the bumper stay and set to a position where the weight is supported by the upper surface of the vehicle rearward extension part. A movable bumper for a dump truck. In the movable bumper of the dump truck according to claim 1 ,
The bumper stay has a stay side stopper plate at a vehicle front position sandwiching the arm support shaft, and a stay side stopper recess at a vehicle rear position sandwiching the arm support shaft,
The bumper arm includes an arm-side stopper plate at a position corresponding to the stay-side stopper plate, and a locking arm that is rotatably supported by a support shaft with respect to the arm plate.
Between the bumper stay and the bumper arm, an arm lock structure for fixing the bumper arm's arm operation at a bumper use position is provided.
The arm lock structure has a stopper pin provided at an end of the locking arm in the recess of the stay side stopper in a state where the stay side stopper plate and the arm side stopper plate are in contact with the front side of the vehicle. A dump bumper movable bumper characterized by having a structure that restricts rotation in the rearward direction of the vehicle by fitting and contacting the vehicle. In the movable bumper of the dump truck according to claim 2 ,
The locking arm has a stopper pin fixed to the upper end portion of the arm, and a spring interposed between the stopper pin and the arm plate,
An arm that applies an urging force to the stopper pin in the contact direction at an arm lock position where the stopper pin is fitted and brought into contact with the stay-side stopper recess, and the stopper pin is removed from the stay-side stopper recess. A movable bumper for a dump truck, characterized in that an urging force is applied to the stopper pin in a releasing direction at the unlocking position. In the movable bumper of the dump truck according to claim 3 ,
A pair of left and right manual operation levers that are arranged in parallel with the stopper pin and extend toward the vehicle center axis are fixed to the pair of locking arms,
The pair of left and right manual operation levers are moved between the arm lock position and the arm lock release position at the bumper use position, and between the bumper use position and the bumper storage position in the unlock state. A movable bumper for a dump truck, characterized in that it is a manual operating means for rotating the bumper arm in between. The movable bumper of the dump truck according to any one of claims 1 to 4 ,
The bumper stay is provided with a stay side bolt hole that is connected to a frame side bolt hole provided in the side frame and fastened and fixed by a bolt and a nut.
When the fixing position of the bumper stay is changed in the height direction, the frame side bolt hole and the stay side bolt hole are secured so that communication between both bolt holes is ensured before or after the change. Dump truck movable bumper characterized by the position of