JP7744678B2 - Support structure for road paving machine and work steps used therein - Google Patents

Description

The present invention relates to a foldable support structure for steps of a road paving machine having an extendable screed.

Conventionally, as described in Patent Document 1, the working step (16) of a road paving machine (the reference numerals in parentheses are those described in the patent document; the same applies below) is attached a predetermined distance away from the rear end face of the screed. This increases the overall length of the paving machine. Therefore, for example, when transporting a road paving machine on a truck, the increased overall length of the road paving machine increases the space required to mount it, necessitating the use of a larger truck, which increases the cost of transporting the paving machine.

To solve this problem, Patent Document 2 discloses a foldable structure for steps on a road paving machine with an extendable screed.

In Patent Document 2, a central step (7) for work is attached to the rear end of an extendable screed (5) consisting of a screed body (9) and extendable screed sections (10, 11). Furthermore, the vertical portion (24) of an L-shaped first bracket (22) is fixed to the screed body (9). A second bracket (23) is connected to the horizontal portion (25) of the first bracket (22) via a roller (32) and roller shaft (31) that allows the second bracket (23) to move horizontally rearward and rotate vertically relative to the rear end surface of the screed body (9). The central step (7) is fixed to the second bracket (23). By pulling the second bracket (23) rearward and rotating it upward relative to the first bracket (22), the central step (7) can be folded into an upright position in contact with or adjacent to the rear end surface of the screed body (9).

The step described in Patent Document 2 can be folded into an upright position in contact with or closely facing the rear end face of the screed body, thereby shortening the overall length of the road paving machine compared to conventional examples. Therefore, for example, when loading the road paving machine onto a truck for transport, only a small space is required for loading the road paving machine, allowing the use of a smaller truck and reducing the cost of transporting the paving machine.

Japanese Patent Application Laid-Open No. 2005-248576 Japanese Patent Application Laid-Open No. 2009-287351

However, in the case of small road paving machines such as those manufactured by the applicant, all functions must be accommodated within limited dimensions. In particular, screeds for road paving machines in the small special vehicle category must fit the equipment into an extremely small compartment.

The construction capabilities of a screed (construction flatness and tracking ability during operation) are determined by the balance of the screed's bottom plate shape, bottom plate surface pressure (kg/ ^cm2 ), etc. However, in the case of small road paving machines, as mentioned above, the screed needs to be contained in a very small compartment, so the bottom plate surface pressure (kg/ ^cm2 ) tends to be high. As a result, it is difficult to balance the above construction capabilities, and operators sometimes complain that operation is difficult.

Figure 8(a) is a side view of a conventional screed device manufactured by the applicant. As shown in Figure 8(a), the step rotates upward relative to the center of rotation as indicated by the arrow in Figure 8(a), and is raised and used during operation. In the screed device, the main bottom plate is located directly below the main frame, the left bottom plate is located directly below the left telescopic frame, and the right bottom plate is located directly below the right telescopic frame.

In the structure shown in Figure 8(a), when work is not being performed, the step needs to be folded downward around the center of rotation and stored. Therefore, the size of all bottom plates, including the right-side bottom plate, needs to be kept small, taking into account the storage space for the step. As a result, the total area of the bottom plates is reduced, which increases the surface pressure on the bottom plates.

The step structure described in Patent Document 2 allows the step to be rotated upward, but because the bracket (22) is L-shaped, the horizontal section 25 protrudes rearward, which may prevent it from fitting into the storage compartment, particularly in the case of small road paving machines.

Based on the above, the present invention aims to provide a road paving machine and a support structure for work steps used therein that can maximize the area of the base plate and store the work steps in a limited space.

In order to solve the above problems, the present invention has the following features: The present invention is a support structure for a work step attached to a screed device of a road paving machine capable of extending and retracting the screed left and right, comprising: a first bracket attached to the left telescopic structure of the screed, a first pivoting bracket attached to the first bracket so as to be pivotable upward, a first telescopic step platform attached to the first pivoting bracket and slidable left and right, a second bracket attached to the right telescopic structure of the screed, a second pivoting bracket attached to the second bracket so as to be pivotable upward, a second telescopic step platform attached to the second pivoting bracket and slidable left and right, and a central step platform attached to the housing of the screed device so as to be pivotable upward.

Preferably, when the screed device is retracted, the first and second telescopic step platforms can be stored inside the central step platform, and the first, second, and central step platforms, as well as the first and second pivoting brackets, can be rotated upward and folded for storage.

Preferably, the connection between the first pivoting bracket and the first extendable step platform is releasable, and the connection between the second pivoting bracket and the second extendable step platform is releasable.

Preferably, the bottom plate of the screed device extends to the lower rear ends of the first and second brackets.

The present invention also relates to a road paving machine equipped with a screed device having the support structure for the working step described above.

According to the present invention, the first extendable step platform, the second extendable step platform, and the central step platform can be rotated upward via the first bracket and first pivot bracket, and the second bracket and second pivot bracket. This allows the lower parts of the support structures for these steps to be left open for the placement of a base plate. This allows the area of the base plate to be maximized, and the work steps can be stored in a limited space.

By making it possible to disconnect each pivot bracket from each extendable step platform, interference with components inside the screed device can be avoided, making it possible to make the step support structure more compact.

These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a side view of a road paving machine 1 when a step structure 5 according to an embodiment of the present invention is rotated downward (during operation). FIG. 2 is a perspective view of the road paving machine 1 when the screed is extended, seen from diagonally above and behind. FIG. 3 is a perspective view of the road paving machine 1 when the screed is extended, seen from diagonally below and behind. 4 is a perspective view showing the structure of the work step from an obliquely upper rear view, in which the work step is shown in a state where it has been rotated downward. Fig. 5 is a perspective view showing the structure of the working step from an obliquely upper rear angle different from that of Fig. 5. In Fig. 5, the working step is shown in a state where it has been rotated downward. 6 is a perspective view showing the structure of the working step from an obliquely upper rear side, in which the working step is shown in a state where it is closed upward. 7A and 7B are front views of the brackets 6a and 6b used in this embodiment, where Fig. 7A is a front view of the bracket 6a, and Fig. 7B is a front view of the bracket 6b. 8A and 8B are diagrams showing the effects of this embodiment, where Fig. 8A is a diagram showing the structure of a conventional work step, and Fig. 8B is a diagram showing the structure of a work step of this embodiment.

As shown in Figures 1 to 3, the road paving machine 1 is equipped with a screed device 1a for spreading and leveling the asphalt mixture delivered from the front hopper, bar feeder, and screw. The screed device 1a of the road paving machine 1 includes a main bottom plate 2, a left bottom plate 3, and a right bottom plate 4. A working step structure 5 is attached to the screed device 1a.

As shown in Figure 1, the step structure 5 can rotate in the direction of arrow A.

As shown in Figures 2 and 3, the step structure 5 comprises a bracket 6a attached to the left telescopic structure of the screed device 1a and a bracket 6b attached to the right telescopic structure. Because the left and right telescopic structures are staggered, the lengths of brackets 6a and 6b are different. In the drawings, the left telescopic structure is at the front of the vehicle and the right telescopic structure is at the rear of the vehicle, so bracket 6a is longer than bracket 6b (see Figure 7).

The left-side extendable step platform 7a is attached to bracket 6a via a pivoting bracket 8. The left-side extendable step platform 7b is attached to bracket 6b via a pivoting bracket 8. The central step platform 7b is pivotally attached to the screed device 1a.

The rotation structure of the step structure 5 will be explained with reference to Figures 4 to 7.

The left end of the left-side extendable step platform 7a has a bent portion 7a-1.

The pivoting bracket 8 is a member that pivotally connects the left-side extendable step platform 7a and the bracket 6a.

It goes without saying that the size of the pivoting brackets 8, 8 can also be adjusted depending on whether they are on the left or right side.

The pivoting bracket 8 has a bent portion 8a that faces the bent portion 7a-1. The bent portion 8a and the bent portion 7a-1 are removably connected by a fastening means 11a (only one is visible in Figure 4, but multiple fastening means may be provided as needed).

The pivoting bracket 8 is pivotally connected to the bracket 6a by fastening means 9a and 9b. The fastening means 9a is attached to the groove 10b in the bracket 6a. The fastening means 9b is attached to the groove 10a in the bracket 6a.

The bracket 6b side has the same structure as the bracket 6a side, so the above description will be used to illustrate and explain the bracket 6b side, and detailed explanation will be omitted.

As shown in Figure 5, the central step platform 7b is attached to left and right pivot shafts 12a and 12b provided on the housing of the screed device 1a.

As shown in Figures 4 and 5, the left-side extendable step platform 7a and the right-side extendable step platform 7c can be slid into storage inside the central step platform 7b.

As shown in Figures 2 and 3, bracket 6a and bracket 6b are connected to the left-side telescopic step platform 7a and the right-side telescopic step platform 7c, respectively, via pivoting bracket 8. When the screed is extended, the left-side telescopic step platform 7a and the right-side telescopic step platform 7c slide left and right in response, emerging from the central step platform 7b.

When the screed retracts, as shown in Figures 4 and 5, the left-side telescopic step platform 7a and the right-side telescopic step platform 7c slide into and are stored inside the central step platform 7b. At this stage, the brackets 6a, 6b and the pivoting brackets 8, 8 are connected by their respective fastening means 11a (the state shown in Figures 4 and 5).

In this state, removing each fastening means 11a releases the connection between the pivot brackets 8, 8 and the left-side extendable step platform 7a and right-side extendable step platform 7c.

By loosening the fastening means 9a, 9b, the pivoting brackets 8, 8 can be pivoted upward along the grooves 10a, 10b in Figures 7(a) and 7(b). At the same time, the central step stool 7b, which houses the left-side telescopic step stool 7a and the right-side telescopic step stool 7c, can be pivoted upward around the pivot axes 12a and 12b. As a result, as shown in Figure 6, the left and right pivoting brackets 8, 8, the left-side telescopic step stool 7a, the right-side telescopic step stool 7c, and the central step stool 7b can be pivoted in the direction of arrow A in Figure 1 and folded upward for storage.

When the left-side telescopic step stool 7a, the right-side telescopic step stool 7c, and the center step stool 7b are folded downward, the brackets 6a, 6b and the pivoting brackets 8, 8 are horizontal. In the case of the conventional steps shown in Figure 8(a), the steps were stored in section D shown in Figure 1, which required the area of each base plate to be reduced by the amount of section D. However, in this embodiment, the steps can be stored upward when the screed is retracted, allowing the area of the base plate to be expanded to the section D shown in Figure 1 near the lower rear ends of the brackets 6a, 6b. As a result, as shown in Figure 8(b), the overall area of base plates 2, 3, and 4 can be increased compared to Figure 8(a).

This embodiment therefore allows the area of the bottom plate to be maximized. Furthermore, the work steps can be stored in a limited compartment.

(Modification)
In the above embodiment, the connection between the pivot brackets 8, 8 and the left-side telescopic step platform 7a and the right-side telescopic step platform 7c is released, but if the shape of the left-side telescopic step platform 7a and the right-side telescopic step platform 7c or the pivot brackets 8, 8 is changed so as to avoid the members 13, 13 present inside the screed device, it is not necessary to release the connection.

The shapes of brackets 6a, 6b and pivoting bracket 8 are not limited to those shown in the illustration; any shape is acceptable as long as pivoting bracket 8 is pivotable relative to brackets 6a, 6b. When pivoting bracket 8 is unfolded downwards, it is sufficient that the pivoting bracket 8 and brackets 6a, 6b are horizontal.

In the above embodiment, opposing bends 7a-1 and 8a are used to connect the pivoting brackets 8, 8 to the left-side telescopic step stool 7a and right-side telescopic step stool 7c, but this is not limited to this. As long as the pivoting brackets 8, 8 are configured to be detachably connected to the left-side telescopic step stool 7a and right-side telescopic step stool 7c, the configuration is not limited to using such bends.

The fastening means 11a for connecting the bent portion 7a-1 and the bent portion 8a may be any type of fastening means, such as a bolt or a pin.

The left-right relationship used in the above explanation may be reversed. Therefore, the left telescopic step platform 7a can be conceptually expressed as the first telescopic step platform, and the right telescopic step platform 7c can be conceptually expressed as the second telescopic step platform. Similarly, the left bottom plate 3 can be conceptually expressed as the first bottom plate, and the right bottom plate 4 as the second bottom plate. Furthermore, if the left and right sides are reversed, the shapes of the brackets 6a, 6b and the swivel brackets 8, 8 can be modified as appropriate.

In the above embodiment, a step structure for a triple screed (using a main bottom plate, left bottom plate, and right bottom plate) is shown, but it can also be applied to a quadruple or more telescopic screed device. That is, when the screed is retracted, the step platforms at both ends are disconnected from the brackets 6a, 6b and pivoting brackets 8, 8 attached to the screed device, all of the step platforms stored in the central step platform are folded upward, and the pivoting brackets 8, 8 are then folded upward.

The present invention has been described in detail above, but the above description is merely illustrative of the present invention in all respects and is not intended to limit its scope. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. Each of the constituent elements of the invention disclosed in this specification is considered to be an independent, stand-alone invention. Inventions in which the constituent elements are combined in any manner are also included within the scope of the present invention.

The present invention relates to a support structure for a road paving machine and a work step used therein, and is industrially applicable.

1 Road paving machine 1a Screed device 2 Main bottom plate 3 Left bottom plate (first bottom plate)
4 Right bottom plate (second bottom plate)
5 Step structure 6a Bracket (first bracket)
6b Bracket (second bracket)
7a Left telescopic step platform (first telescopic step platform)
7a-1 Bending section 7b Central step 7c Right telescopic step (second telescopic step)
8. Rotating bracket (first rotating bracket, second rotating bracket)
8a Bent portion 9a, 9b Fastening means 10a, 10b Groove 11a Fastening means 12a, 12b Rotation shaft

Claims (5)

A support structure for a work step attached to a screed device of a road paving machine that can extend and retract the screed to the left and right,
a first bracket attached to the left telescoping structure of the screed;
a first pivot bracket attached to the first bracket so as to be pivotable upward;
a first extendable step platform attached to the first pivot bracket and slidable to the left and right ;
a second bracket attached to the right telescoping structure of the screed;
a second pivot bracket attached to the second bracket so as to be pivotable upward;
a second extendable step platform attached to the second pivot bracket and slidable left and right ;
A support structure for a work step, characterized in that it comprises a central step base attached to the housing of the screed device so as to be rotatable upward. When the screed device is retracted, the first extendable step platform and the second extendable step platform can be stored inside the central step platform;
2. The support structure for work steps according to claim 1, wherein the first extendable step platform, the second extendable step platform, the central step platform, the first pivot bracket, and the second pivot bracket can be rotated upward and folded for storage. The connection between the first pivot bracket and the first extendable step platform is releasable,
3. The support structure for a work step according to claim 2, wherein the connection between the second pivot bracket and the second extendable step platform is releasable. A support structure for a work step according to any one of claims 1 to 3, characterized in that a bottom plate of the screed device is provided up to the lower rear ends of the first and second brackets. A road paving machine comprising a screed device having a support structure for a working step according to any one of claims 1 to 4.