JPS6318548Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cab tilt device used in a large cab-over type vehicle.

In large cab-over type trucks, the engine room is located under the driver's cab, which is called a cab.In order to perform maintenance and inspection of the engine inside, a cab tilt system is used to lift the cab and tilt it forward. equipment is provided.
It has been known to use a hydraulic cylinder as the tilt cylinder of such a cab tilt device, but in general, the piston of a hydraulic cylinder becomes oil-locked when the oil flow stops. The vibration of
It is necessary to provide a so-called lost motion mechanism in order to absorb shock and the like and improve riding comfort for the occupant.

Since this lost motion mechanism allows relative movement between the cab side and the chassis side, it is required to satisfy the following two conditions. The first is when the cab is raised and placed in a forward leaning position with respect to the seat.
If the center of gravity of this cab moves beyond the center of tilt with respect to the chassis and moves to the front of the vehicle body, it is necessary to prevent the cab from rapidly tipping forward due to its own weight, and as a second condition, the cab tilt If the locking device that connects the cab and the chassis at a predetermined interval when the device is not in operation is forgotten or malfunctions, this prevents the cab from rising above the lost motion range while driving. must also be prevented.

Various types of lost motion mechanisms have been proposed in the past, but none of them can be said to fully satisfy the above-mentioned conditions. For example, Japanese Patent Application Laid-open No. 57-205279 discloses a connection device that can connect the cab and the piston rod of a hydraulic cylinder in and out, and engages the cab when the cab is tilted.
A mechanism has been shown in which the cab is detached when not tilted so as not to impair the cushioning effect of the cab, but this configuration does not have a safety device to prevent the cab from flying up in the event of forgetting to attach the cab or failure.

The present invention was developed in view of the above points, and is intended to provide a cab tilt device equipped with a safe and reliable lost motion mechanism that prevents the cab from flipping up during driving and falling when tilting. A cab rotatably connected via a tilt shaft, a rotating arm whose one end is pivotally supported by a bracket fixed to the chassis, and whose engaging portion provided at the other end is located below the cab; A cylinder is provided, the end of which is connected to the chassis, and the piston rod of which is pivotally connected to the rotary arm. When the cylinder is operated, the engaging portion of the rotary arm pushes up the lower surface of the cab, causing the tilt shaft to move. In a cab tilt device that tilts the cab at the center,
The pivot point of the rotating arm to the bracket is separated from the tilt axis, and the bracket fixed to the cab has an approximately L-shape consisting of a vertical hole that is wider than a horizontal hole that is slightly wider than the outer diameter of the engaging portion. An elongated hole is formed, and the engaging portion is positioned in the vertical hole when the cylinder is not in operation, and fitted into the horizontal hole when the cylinder is in operation.

Hereinafter, the present invention will be explained based on illustrated embodiments. FIG. 1 is a side view showing an example of a cab tilt device applied to a cab-over type vehicle, in which a cab 1 is rotated relative to the chassis 2 via a tilt shaft 4 at the center of a bracket 3 fixed to the chassis 2. movably connected. This bracket 3
At a position above the tilt axis 4, there is a rotating arm 5.
One end 5a is pivotally supported, and the other end 5b of the rotating arm 5 is provided with an engaging portion 6 that supports and raises the lower surface of the cab 1 when the cab tilt device is operated. Note that this engaging portion 6 is preferably a rolling element such as a roller. On the other hand, a substantially L-shaped elongated hole 8 is formed in a bracket 7 fixed below the cab 1. This elongated hole 8 is a horizontal hole 9 having a width slightly larger than the outer diameter of the engaging portion 6.
and a vertical hole 10 which is connected downward from the front (left side in FIG. 1) end of the horizontal hole 9 in the direction of travel of the vehicle and has a wider width than the horizontal hole 9.
The engaging portion 6 of the rotating arm 5 is located approximately at the center of the vertical hole 10 with a predetermined gap in the longitudinal and vertical directions of the vehicle when the cab tilt device is not in operation, that is, when the cab 1 is lowered. Further, the hydraulic cylinder 11 has its base end 11a pivoted to the chassis 2, and the tip end 12a of the piston rod 12 to the intermediate part of the rotating arm 5, respectively.

Here, the operation of the cab tilt device according to the above configuration will be explained. When the vehicle is running with the cab tilt device inactive, the vibrations, shocks, etc. of cab 1 will be
This is absorbed by the gap between the wide vertical hole 9 and the engaging part 6, and even if the cab block is forgotten or malfunctions, there is no risk that the cab 1 will jump up beyond the range that the gap allows, making it safe. A reliable lost motion function can be obtained. On the other hand, when tilting the cab 1, when the hydraulic cylinder 11 is activated, the pivot arm 5 moves toward the bracket 3 due to the extension of the piston rod 12.
The engaging portion 6 is rotated about the pivot 5a as a fulcrum.
After contacting the upper surface 8a of the elongated hole 8, it is pushed up to tilt the cab 1 about the tilt shaft 4 as the center of tilt. At this time, the engaging portion 6 of the rotating arm 5
and the elongated hole 8 of the cab side bracket 7 are both the first
Although it is rotated counterclockwise in the figure, since the rotation centers of the two are different and the rotation center of the arm 5 is upward, the engaging portion 6 gradually moves to the side hole 9 of the L-shaped hole 8.
fit inside. In this way, when tilting (first
(shown by imaginary lines in the figure), the engaging portion 6 is engaged with a slight gap in the side hole 9, so even if the center of gravity of the cab 1 moves forward beyond the tilt center, It is possible to prevent the cab 1 from falling over.

As described above, the device of this embodiment can reliably achieve the conditions required for a lost motion mechanism, such as preventing the cab from flying up in the event of a cab block failure, and preventing the cab from tipping over during tilt-up, with a simple configuration. can. Furthermore, the point of action on the cab during tilt can be moved further away from the center of tilt compared to conventional models.
Another effect is that no excessive force is applied to the cab. In addition, the piston rod 12 is connected to the rotating arm 5.
The tip 5b of the rotating arm 5 is not pivoted to the center of the
Even when coupled to the above, the above conditions required for a lost motion mechanism can be satisfied.

FIGS. 2a and 2b show another example in which a part of the above-mentioned embodiment is modified. In the above-mentioned embodiment, an L-shaped elongated hole 8 cut out from a flat plate-like bracket 7 and a cylindrical engagement are shown. In this example, the engaging part 6 at the tip of the rotating arm 5 is formed into a spherical shape, whereas the hole 8 on the cab 1 side has a spherical engaging part 6. Vertical shallow hole 1 accommodated with the required gap
0, and a small-diameter deep hole 9 extending from the top of the shallow hole 10 toward the rear of the vehicle. In this example as well, when traveling, the spherical engaging portion 6 is allowed relative movement within a predetermined range within the shallow hole 10, and when tilting,
Since the engaging portion 6 enters the deep hole 9 and its relative movement is restricted, the conditions for the lost motion mechanism described above can be satisfied.

Next, another embodiment will be described with reference to FIG. In this embodiment, unlike the embodiment shown in FIG. Therefore, when the device of this embodiment is operated, the engaging portion 6 moves from the upper part of the vertical hole 10 toward the front in the direction of travel of the vehicle, so that the horizontal hole 9 is placed in the opposite position to that in FIG. 1, that is, in the direction of travel of the vehicle. It is formed towards the front. Note that the other parts are the same as those in the first embodiment, so their explanation will be omitted. It goes without saying that even with this configuration, the same effects as in the above embodiment can be achieved.

As described above, according to the present invention, it is possible to obtain a cab tilting device with an extremely simple configuration that is equipped with a safe and reliable lost motion mechanism that can prevent the cab from tipping over when tilting and from flying up while driving. can.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a cab tilt device according to one embodiment of the present invention, Fig. 2 a is a vertical sectional view showing a part of another embodiment, and Fig. 2 b is taken along line bb in Fig. a. The sectional view and FIG. 3 are side views showing still another embodiment. DESCRIPTION OF SYMBOLS 1... Cab, 2... Seat, 3... Shaft side bracket, 4... Tilt axis, 5... Rotating arm, 5a... Pivoting point of rotating arm, 6... Engaging portion, 7... Cab side bracket, 8...L-shaped oblong hole, 11...cylinder, 12...piston rod.

Claims (1)

[Scope of utility model registration request] A cab that is rotatably connected to the chassis via a tilt shaft, one end of which is pivotally supported by a bracket fixed to the chassis, and an engaging part provided at the other end that is located below the cab. an arm, and a cylinder whose base end is pivotally connected to the chassis and whose piston rod is pivotally connected to the rotary arm, and when the cylinder is operated, the engaging portion of the rotary arm pushes up the lower surface of the cab, In the cab tilt device that tilts the cab about the tilt axis, the pivot point of the rotating arm to the bracket is spaced apart from the tilt axis, and the bracket fixed to the cab is provided with a width slightly wider than the outer diameter of the engaging portion. forming a substantially L-shaped elongated hole consisting of a wide horizontal hole and a vertical hole wider than the horizontal hole, and positioning the engaging portion in the vertical hole when the cylinder is not in operation;
A cab tilt device that fits into the side hole when the cylinder is activated.