JPS6124454Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cab tailing device used in a tipped cab automobile or the like.

In order to improve the ease of tilting the cab in a tilted cab automobile, the tip of the piston rod of a hydraulic cylinder attached to the frame is connected to the cab so that the cab can be tilted up or down by operating a switch or a lever. Yes (Jitsukai 55-139972
(Reference).

As a hydraulic cylinder device for such a cab tail, an oil lock type is generally used to prevent the cab from falling by itself even when the hydraulic pump is inadvertently stopped. However, if, for example, the hydraulic piping is damaged or the oil-tight function of the hydraulic cylinder deteriorates due to abnormal wear, the locking function of the hydraulic cylinder will deteriorate, causing the cab in a tilted state to fall under its own weight. There is a risk of it getting lost. Therefore, in the past, even if an oil lock type hydraulic cylinder was adopted, the frame and cab were connected through a mechanical locking means to prevent the cab from falling by itself in the unlikely event of an accident. was.
However, in order to reliably prevent the cab from falling, it is necessary to provide a large locking means with a sufficient safety factor in mind, which has the drawback of increasing the weight and cost of the cab tilt device.

In addition, in order to prevent the cab from falling due to trouble in the hydraulic system, a one-way brake mechanism such as that seen in Japanese Patent Application Laid-open No. 15977/1982 or Japanese Utility Model Application No. 82890/1983 is attached to the hydraulic cylinder. is valid.

However, in the former one-way brake mechanism in which a movable wedge plate is in sliding contact with the piston rod of a hydraulic cylinder, if the sliding surface between the movable wedge plate and the piston rod is worn out and the piston rod is worn or damaged, the hydraulic pressure Because the sealing performance of the cylinder is impaired, when the hydraulic cylinder is operated, it is necessary to forcibly expand and narrow the movable wedge plates facing each other across the piston rod, which complicates the structure of the one-way brake mechanism. There is a problem with this. Furthermore, even in a one-way brake mechanism such as the latter, in which a brake plate passing through the piston rod is tilted to perform a predetermined braking action, the same problem as described above occurs because the piston rod is easily damaged by the brake plate. It was hot.

The present invention was developed in view of the above-mentioned circumstances, and is a one-way design with a simple structure that accurately prevents the cab from falling due to troubles in the hydraulic system, etc., and that does not pose any risk of adversely affecting the sealing performance of the hydraulic cylinder. The purpose of this invention is to improve the operability and safety of a cab tilt device by attaching a brake mechanism to the upper end of a hydraulic cylinder so that the hydraulic cylinder also functions as a cab locking means.

In order to achieve such an object, in the present invention, a pair of elongated holes are formed at opposite positions sandwiching the piston rod, and are inclined so as to approach each other in the retracting direction of the piston rod of a hydraulic cylinder that operates the cab in a tail-up manner. A one-way brake mechanism is constructed by holding rollers slidably attached to each elongated hole in rolling contact with the piston rod,
The one-way brake mechanism is attached to the upper end of the hydraulic cylinder. Further, a release mechanism is provided for moving the roller in the direction of protrusion of the piston rod along the elongated hole to release the braking function of the one-way brake mechanism, and an operating part of the release mechanism is mounted on the frame. It is said that

With this configuration, the piston rod is prevented from being damaged by the one-way brake mechanism that prevents the piston rod from freely moving in the retracting direction, and the sealing performance of the hydraulic cylinder is prevented from being impaired. The aim is to improve the operability and safety of the equipment.

An embodiment of the present invention will be described in detail below with reference to the drawings.

A cab 3 is tiltably mounted on the front end of a frame 2 that supports a cargo platform 1 to form a cab-over type truck. 4 is a tail hinge pin of the cab 3 attached to the frame 2 via a front mount device (not shown), and 5 is a hinge bracket fixed to the lower surface of the cab 3, which connects the rear end of the cab 3 and the frame to the cab lock mechanism. They are removably connected via a rear mount device 6 provided therein.

A hydraulic cylinder 8 is connected to the side surface near the front end of the frame 2 via a pin 7 parallel to the hinge pin 4.
The lower end of the hydraulic cylinder 8 is pivotally connected, and the upper end of the piston rod 9 of the hydraulic cylinder 8 and the rear end of the hinge bracket 5 are connected to a pin 1 parallel to the hinge pin 4.
0, when the piston rod 9 is operated in a protruding manner, the cab 3 is tilted up around the hinge pin 4 as shown by the dashed line in FIG. It is designed to be tilted down from the position shown by the dashed line in the figure to the position shown by the solid line. Incidentally, each oil chamber formed in the hydraulic cylinder 8, sandwiching the piston (not shown) of the piston rod 9, is connected to a hydraulic pump (not shown) via a conventionally known hydraulic circuit. Reference numeral 11 indicates a hydraulic hose, and reference numeral 12 indicates a directional switching valve attached to the frame 2. When the switching valve 12 is switched between a raised position and a lowered position, the hydraulic pump is driven by a motor or the like.

According to the present invention, a one-way brake mechanism 13 is provided at the upper end of the hydraulic cylinder 8 to prevent the piston rod 9 from being inadvertently retracted. As shown in FIGS. 3 and 4, for example, this one-way brake mechanism 13 includes a roller holder 14 fixed to the upper end of the hydraulic cylinder 8, and a pair of drum-shaped rollers 15 facing each other with the piston rod 9 in between. The spindle 16 of the roller 15 is inserted into and held in a vertically extending elongated hole 17 formed in the roller holder 14 so as to be rotatable and vertically movable. Further, by slanting the elongated holes 17 so as to approach the piston rod 9 as they go downward, the roller 15 is held in rolling contact with the piston rod 9 by its own weight. Therefore, when the piston rod 9 tries to retract, the roller 15 is strongly pressed against the piston rod 9, thereby preventing the rod 9 from retracting (braking). Since the roller 15 tends to be lifted by the rolling action with the rod 9, the movement prevention action by the roller 15 is not performed.

Further, a release member 18 serving as a release mechanism is inserted into the lower part of the outer peripheral surface of the roller holder 14 so as to be movable up and down. An appropriate play is provided between the upper surface of the release member 18 and the support shaft 16 of the roller 15, and the cover 19 and the release member 18 are normally
The release member 18 is held in contact with the upper surface of the hydraulic cylinder 8 by a spring 20 stretched between the support shaft 16 and the release member 18 to prevent interference between the support shaft 16 and the release member 18. The release lever 21 and the release member 18 are attached near the hydraulic pressure switching valve 12.
and the control wire 22 and roller holder 14
When the release lever 21 is rotated from the lock position shown in FIG. 2 to the release position by rotating it in the direction of the arrow shown in FIG. Release member 1 against
8 is raised to raise the roller 15 along the elongated hole 17.

In the above configuration, when the cab is set, the piston rod 9 is connected to the hydraulic cylinder 8 as shown in FIG.
The cab 3 is held in a substantially horizontal state by immersing the cab deeply inside. Further, since the release lever 21 is normally held in the locked position, the release member 18 is separated from the support shaft 16 of the roller 15. Therefore, the roller 15 rolls into contact with the piston rod 9 under its own weight and prevents the piston rod 9 from retracting, thereby preventing the cab 3 from vertically vibrating. In addition, when the lost motion function is provided, the release lever 21 is switched and held in the release position to move the piston rod 9 in and out (elevating and lowering).
need to be allowed.

To tail-up the cab 3, remove the cab lock mechanism (not shown) and press the release lever 2.
1 is held in the locked position, and the directional control valve 12 is switched to the raised position. Then, the pressure oil sent out from the hydraulic pump is sent into the oil chamber below the piston, so that the piston rod 9 is operated to protrude.
As the piston rod 9 protrudes, the cab 3 gradually rotates upward about the hinge pin 4. Incidentally, at the time of such tail-up, the piston rod 9 moves to protrude, so that the roller rotates freely.

When the directional control valve 12 is returned to the neutral position, the piston rod 9 stops because pressure oil is no longer supplied to the hydraulic cylinder. If an oil leak occurs in this condition,
Piston rod 9 bearing the weight of cab 3
tries to immerse himself in it. However, when moving in this direction, the rollers 15 perform a braking action, so there is no risk that the piston rod 9 will become recessed.
You can prevent Cab 3 from falling by itself. Therefore, there is no need to provide a special locking mechanism between the frame 2 and the cab 3.

Further, when tilting down the cab 3, the release lever 21 is switched and held at the release position. Then, the release member 18 is pulled up against the spring 20 and pushes the roller 15 up along the elongated hole 17. Since the elongated hole 17 that guides the roller 15 is inclined, when the release member 18 pushes up the roller 15, the roller 15 is pushed up.
5 is separated from the piston rod 9. Therefore, even if the piston rod 9 is retracted by switching the directional control valve 12 to the lower position, if the release lever 21 is held at the release position, the roller 1
No braking action is performed by 5. still,
It is needless to explain in detail that the cab 3 rotates downward about the hinge pin 4 as the piston rod 9 retracts.

In the embodiment, the release lever 21 is provided independently. For example, when the directional control valve 12 is being operated to switch between the neutral position and the raised position, the release member 18 is positioned at the lower end, and the directional control valve 12 is moved. The release member 18 may be automatically held raised and released from the braking action by the roller 15 only during the switching operation to the lowered position.

Further, in the embodiment, an hourglass-shaped roller is used to increase the contact area between the roller and the piston rod, but a cylindrical roller may also be used.

As explained above, according to the present invention, a one-way brake mechanism is interposed between the hydraulic cylinder attached to the frame and the piston rod connected to the cab to form a lock mechanism that prevents the cab from falling. Therefore, the reaction force of the cab transmitted via the piston rod can be received by the hydraulic cylinder. Therefore, unlike the conventional cab tail device, there is no need to use a strong and long stay, so the cab tail device can be made smaller and lighter and provided at a lower cost. Further, since a one-way brake mechanism is constructed by rolling a roller slidably mounted in an inclined elongated hole into rolling contact with the piston rod, the roller rolls extremely easily in the direction in which the piston rod protrudes. For this reason, even if the cab tail-up operation is performed without releasing the one-way brake mechanism, the piston rod, which has a serious effect on the sealing performance of the hydraulic cylinder, as well as the rollers that provide the braking force to the piston rod will wear out. The hydraulic cylinder can be easily extended without causing damage. Therefore, it is possible to prevent the cab from falling not only from the tilted position, but also from falling when the cab is tilted up, so that the cab can be tilted safely. Furthermore, since the operating means for the release mechanism that releases the one-way brake mechanism is attached to the frame, the one-way brake mechanism can be set or released from the tail operation position, for example, so the ease of tilting the cab can be improved. .

[Brief explanation of the drawing]

FIG. 1 is a side view of a part of a truck equipped with an embodiment of the present invention, FIG. 2 is a side view of the main parts of the same, and FIG.
The figure is a partially cutaway side view showing the upper end portion of the hydraulic cylinder, and FIG. 4 is a sectional view taken along line AA in FIG. 3. 2... Frame, 3... Cab, 4... Tail hinge pin, 7, 10... Pin, 8... Hydraulic cylinder, 9... Piston rod, 11... Hydraulic hose, 12... Directional switching valve, 13... ... One-way brake mechanism, 18 ... Release member (mechanism), 21
...Release lever (operation part).

Claims (1)

[Scope of utility model registration request] By mounting a cab on a frame equipped with a hydraulic cylinder so that it can be tilted, and connecting the tip of the piston rod of the hydraulic cylinder to the cab,
In the tailed cab vehicle in which the piston rod is operated to project and the cab is tilted up, a pair of elongated holes are formed at opposite positions sandwiching the piston rod and are inclined so as to approach each other as the piston rod retracts. A one-way brake mechanism is constructed by holding rollers slidably attached to the long holes in rolling contact with the piston rods, and the one-way brake mechanism is attached to the upper end of the hydraulic cylinder, and the rollers are fitted along the long holes. 1. A cab tailing device for a vehicle, comprising: a release mechanism for releasing the braking function of the one-way brake mechanism by moving the piston rod in the direction in which the piston rod protrudes; and an operating part of the release mechanism is mounted on the frame.