JPS6243867Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a descent prevention device for a transport vehicle, such as a truck or other load lifting device.

For example, a cargo vehicle may be provided with a cargo lifting device at the rear thereof for loading and unloading cargo into the cargo box. Some of these load lifting devices include a reversing arm that rotates up and down, a loading platform supported at the tip thereof, and the reversing arm and loading platform are raised by the action of a hydraulic cylinder. In such devices, the lowering of the reversing arm and the loading platform is
By switching the hydraulic circuit of the hydraulic cylinder, the loading platform is lowered to the ground by the weight of the lifting device.

When the vehicle is in motion, the load lifting device must be kept in the raised position to prevent it from contacting the ground and being damaged. However, if there is oil leakage from the hydraulic cylinder or its hydraulic circuit due to the weight of the lifting device or vibrations caused by running, the reversing arm or loading platform of the lifting device in the raised position may descend. can occur. To deal with this, the lifting device is suspended from the rear frame of the cargo box using metal fittings to prevent it from descending.

However, when removing the suspended metal fittings, if there is oil leakage, a descending force (weight) is applied to the lifting device, so removing the metal fittings itself requires excessive effort.

The present invention was developed in view of the above circumstances, and its purpose is to ensure that even if there is an oil leak, there will be almost no descent due to the weight of the lifting device, and that the lifting device can be reliably locked. To provide a safe and simple descent prevention device for a load lifting device, etc., which requires almost no effort when releasing the lock for lowering the lifting device.

According to the present invention, a load lifting device, such as a load lifting device, which has a reversing arm that is rotatably displaceable between a rising position and a downwardly rotated lowering position, holds the reversing arm in the rising position. This device is a fall prevention device, and a locking pin that contacts the side edge of the reversing arm in the upright position and prevents it from falling is inserted into a horizontal hole provided in a bracket fixed to the support of the load lifting device. The locking pin is slidably displaced in the axial direction between a locking position where the locking part with the side edge of the reversing arm is on the rotational trajectory of the side edge of the reversing arm and a non-locking position where it is off the rotational trajectory. There is provided a drop prevention device characterized in that it is freely rotatable and can be rotated around an axis, and that a portion of the circumferential surface of the locking portion of the locking pin is chamfered.

Next, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes the chassis of a truck as an example of a transport vehicle, on which a cargo box 2 is mounted. A support part 3 is provided protruding from the lower side of the rear end of the cargo box 2, and a pair of upper and lower reversing arms A are attached to this support part 3.
1 and A2 are pivotally connected by pinches 4 and 5.
These reversible arms A ₁ and A ₂ rise upward as they reach their tips, and when viewed from the side as shown in FIG. 1, their tips overlap. The reversing arm A ₁ has a pin 6 at its tip, and the reversing arm A ₂ has a pin 7 at its tip, and these pins 6 and 7 connect a connecting link 8 (both reversing arms
A ₁ and A ₂ are also shown in dashed lines at the positions shown by the dashed lines, where they have rotated somewhat in the downward direction around pins 4 and 5)
Both ends are pivotally connected to the tips of both reversing arms A ₁ and A ₂ . The reversing arms A ₁ and A ₂ are also provided on the other side of the cargo box ₂ , and the base of the loading platform 9 is supported by means such as pivoting across the lower reversing arms A 2 and A ₂ . At the rising position (solid line position) of both reversing arms A ₁ and A ₂ , the loading platform 9 is folded up along the rear surface of the loading box 2 , and both reversing arms A ₁ , A ₂ and loading platform 9 are attached to the loading box using the latch 10 . It can be locked to the metal fitting 11 on the second side.

When the latch 10 is removed, the reversing arms A ₁ , A ₂ ,
The load lifting device such as the loading platform 9 is lowered by its own weight through the chain line position in FIG. 1, and the loading platform 9 is lowered to the ground while maintaining its horizontal position. On the other hand, the force of a hydraulic cylinder (not shown) is used to raise the load lifting device for loading the load. Then, after loading is completed,
The reversing arms A ₁ , A ₂ , loading platform 9, etc. are held at the solid line positions in FIG.

In order to maintain the reversing arm, the loading platform, etc. in the raised position, the present invention includes a drop prevention device 13. This fall prevention device 13 is a reversing arm
A bracket 15 is fixed to the middle part of _A2 to prevent its downward rotational displacement, and is fixed to the vehicle body side, that is, the cargo box side, etc., as shown in FIGS. 2 and 3. It is mainly composed of the protruding pieces 15a and a locking pin 16 inserted into the horizontal hole of the 15a. The locking pin 16 has a locking portion 16a at its tip, and is urged rightward in FIG. 3 by a spring 17. An operating portion 16b bent at a right angle is provided at the base end of the locking pin 16. Push the locking pin 16 to the left in FIG.
8, the locking pin 16 is fixed at the locking position, and its locking portion 16a comes into contact with the side edge of the reversing arm _A2 to prevent its descent. In addition, the operation section 1
6b is fixed to the stopper 18 by rotating the locking pin 16.
When removed from the locking pin 16, the force of the spring 17 causes the locking pin 16 to slide to the right in FIG.
comes into contact with the right protrusion 15a and the locking pin 16 stops moving, so when the user releases the hand, the operating portion 16b moves down to the chain line position. As a result, the locking portion 16a assumes a non-locking position away from the reversing arm _A2 .

The locking portion 16a of the locking pin 16 has a chamfered shape as shown by 20 on a part of its circumferential surface as shown in Fig. 4. The chamfered portion 20 is usually formed to have a flat surface, but it does not necessarily have to have a flat surface. The chamfered portion 20 faces upward when the operating portion 16b faces downward as shown in Fig. 5, and faces downward when the operating portion 16b faces downward as shown in Fig. 6.
is arranged so as to face the inversion arm _A2 when it is horizontally oriented.

Therefore, when the locking portion 16a is in contact with the reversing arm _A2 as shown by the solid line in FIG.
As is clear from FIG. 5, the circumferential surface of the locking portion 16a suppresses the rotation of the reversing arm _A2 and prevents the lifting device from descending. But like this inverted arm A ₂
As mentioned at the beginning, excessive effort is required to bring the locking pin into the unlocked state while the weight of the lifting device is acting on the locking pin (due to a leak in the hydraulic system).

However, in the present invention, when the operating section 16b is rotated to the horizontal position shown by the chain line in FIG. 2, the chamfered section 20 faces the reversing arm _A2 , as is clear from FIG. There will be a gap, so
No particular effort is required to move the locking pin 16 horizontally toward the non-locking position.

In addition, since the fall prevention device 13 almost eliminates the fall due to the weight of the lifting device, the weight of the lifting device is reduced by the weight of the metal fitting 1.
0 and 11, and there is no problem in removing the metal fittings 10 and 11.

As described above, according to the present invention, it is possible to obtain a descent prevention device that can reliably prevent the descent of a load lifting device, etc., and does not require any effort to operate it to the unlocked state. Note that the present invention can also be used to prevent the descent of other mechanisms similar to load lifting devices.

[Brief explanation of the drawing]

Figure 1 is a side view showing the cargo lifting device for a transport vehicle to which the present invention has been applied, Figure 2 is an enlarged side view of the main parts, Figure 3 is an elevational view of the same as seen from the right, and Figure 4 is the locking pin. FIGS. 5 and 6 are perspective views showing the locking portion of the locking pin, and partially sectional side views showing the relationship between the locking portion of the locking pin and the reversing arm in different states. 2...Logging box, _A1 , _A2 ...Reversing arm, 4,
5, 6, 7... Pivot pin, 8... Connection link, 9
... Loading platform, 13 ... Drop prevention device, 15 ... Bracket, 16 ... Locking pin, 16a ... Locking part,
16b... Operating unit, 17... Spring, 18... Stopper, 19... Contact ring, 20... Chamfered portion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) To hold the reversing arm in the upright position of a load lifting device, etc., which has a reversing arm that can be rotated freely between the upright position and the lowered position rotated downward from the upright position. A fall prevention device for a load lifting device, etc., in which a horizontal hole provided in a bracket fixed to a support of the load lifting device contacts the side edge of the reversing arm in the upright position and prevents the arm from falling. The locking pin is inserted between the locking position where the locking part with the side edge of the reversing arm is on the rotational trajectory of the side edge of the reversing arm and the non-locking position where it deviates from the rotational trajectory. It can be slidably displaced in the axial direction, and can be rotated freely around the axis.
Furthermore, a fall prevention device is characterized in that a part of the circumferential surface of the locking portion of the locking pin is chamfered. (2) The fall prevention device according to claim 1, wherein the locking pin has an operating portion at one end. (3) The drop prevention device according to claim 1 or 2, wherein a part of the peripheral surface of the locking portion of the locking pin is chamfered to form a flat surface. (4) The locking pin is elastically biased to a non-locking position where the locking portion does not lock with the side edge of the reversing arm;
On the other hand, the descent according to claim 1 of the utility model registration claim is provided with means for resisting this elasticity and holding the locking pin in a locking position where the locking portion locks the side edge of the reversing arm. Prevention device.