JP2007145140A - Cab descent preventive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage to a shock-absorbing member for noise prevention by a stopper when a vehicle is traveling. <P>SOLUTION: A cab descent preventive device comprises a cylinder device 3 interposed between a cab 1 and a frame 2, a stopper 6 which is turnably and pivotably attached to an end of a piston rod 4 pivotably attached to the cab 1 side of the cylinder device 3, a descent preventive member 10 which is arranged in a moving area of the stopper 6 of the cylinder device 3 to prevent the movement of the stopper 6 to the frame 2 side, and a shock-absorbing member 8 for preventing generation of the noise by mitigating the shock when the stopper 6 collides with the cylinder device 3. A pair of chamfered parts 30, 30 are formed on inner surfaces of both side walls at an end of the frame 2 side of the stopper 6 so as to form a tapered surface to constitute an angle of attack to be gradually increased toward an opening edge of the stopper 6. When the stopper is inclined, both chamfered parts receive the shock-absorbing member to prevent the stopper from riding on the shock-absorbing member, preventing damages on a side surface of the shock-absorbing member of a stopper edge. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a cab lowering prevention device for preventing a cab from descending due to its own weight in a cab over engine type automobile, and more particularly to a cab lowering suitable for being attached to a cab tilting device that lifts and tilts a cab with a cylinder device. The present invention relates to improvement of the prevention device.

In general, in a cab-over type automobile, the maintenance and inspection work for the engine portion and the engine lowering work can be easily performed by lifting and tilting the cab.
In such a case, since the cab is heavy, as shown in FIG. 1, the cylinder device 3 is interposed between the cab 1 and the frame 2, and the cab 1 is tilted by the expansion and contraction operation of the cylinder device 3. A carbitol device configured to perform the operation is used.

In a conventional cabylt device, a cab lowering prevention device is provided as shown in FIG. 1 in case a failure occurs in a cylinder device or its hydraulic circuit.
That is, the cab lowering prevention device includes a stopper 6 pivotally attached to the upper end portion of the piston rod 4 of the cylinder device 3, and the engaging portion 7 </ b> A of the stopper 6 is engaged with the lowering prevention member 10 of the cylinder device 3. Thus, the lowering of the piston rod 4 is mechanically prevented.
As will be described later, the engaging portion 7B of the stopper 6 is an engaging portion for operating a switch for stopping the drive motor of the hydraulic pump when the cab tilt angle reaches the maximum tilt angle.

  In such a cab lowering prevention device, there is a case where the stopper 6 is loosely caused by vibration during traveling of the vehicle and collides with the cylinder device 3 to generate noise.

In view of this, there is a cab lowering prevention device that prevents the occurrence of noise by providing a buffer member 8 such as a resin between the outer peripheral surface of the cylinder device 3 and the stopper 6. For example, see Patent Document 1.
No. 5-15195

  However, in the above-described cab lowering prevention device, if the stopper tilts when the stopper descends after the piston rod extends, the stopper interferes with surrounding structures or the buffer member is damaged. There is a problem of doing.

  An object of the present invention is to prevent the buffer member from being damaged even when the stopper of the cabylt device is tilted when the cab is lowered to return to the original position after being tilted to the maximum tilt angle. An object of the present invention is to provide a cab lowering prevention device.

A cab lowering prevention device according to the present invention is pivotally attached to an end of a cylinder device interposed between a cab and a frame and a piston rod pivotally attached to the cab side of the cylinder device. A stopper that is disposed near the stopper movement region of the cylinder device to prevent the stopper from moving toward the frame, and an impact when the stopper collides with the cylinder device. In the cab lowering prevention device provided with a buffer member that relaxes and prevents noise generation,
Between the stopper and the buffer member, a climbing prevention portion for preventing the stopper from climbing on the buffer member at the frame side end portion is provided.

  According to the above-described means, it is possible to prevent the phenomenon that the stopper rides on the buffer member, so that the buffer member can be prevented from being damaged by the stopper.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present embodiment, the cab lowering prevention device according to the present invention is attached to the cabbutyl device as shown in FIG. That is, one end portion of the stopper 6 is pivotally attached to the upper end portion of the piston rod 4 attached to the cab side (hereinafter referred to as the upper side) of the cylinder device 3 of the cabylt device. The stopper 6 is always urged in the direction of the cylinder 5 of the cylinder device 3 (clockwise direction in FIG. 1) by a torsion spring (not shown) mounted on the pivotal attachment portion.
As shown in FIGS. 2 and 3, the stopper 6 is formed into a long channel steel bar using a rigid metal material. A plurality of engaging portions 7A and 7B are formed on one end side of the stopper 6, respectively.

  As shown in FIGS. 2 and 4, the metal stopper 6 and the cylinder 5 collide with each other in the region facing the stopper 6 on the outer peripheral surface of the cylinder 5 attached to the frame side in the cylinder device 3. A shock-absorbing member 8 for preventing the generation of noise by being put together is covered and fixed. The buffer member 8 is formed by using a resin, and by reducing the impact when the stopper 6 collides with the buffer member 8, the generation of noise is prevented.

As shown in FIG. 2, a pair of lowering prevention members 10 and 10 are disposed on the outer periphery of the upper end portion of the cylinder 5 and fixed by welding. Both descending prevention members 10 and 10 are formed in a rectangular flat plate shape, and are arranged and fixed in parallel with the axis of the cylinder 5.
The upper end surfaces of the lowering prevention members 10 and 10 are configured to engage with the engaging portions 7A and 7B of the stopper 6, respectively. It is comprised so that it may contact | abut the edge of the side in which the engaging parts 7A and 7B were formed.

A first bracket 11 and a second bracket 12 both formed in an angle steel shape are arranged on the outer periphery of the upper end portion of the cylinder 5 and fixed by welding.
The first bracket 11 has a first pin 13 projecting outward at a right angle to the axis of the cylinder 5, and the first pin 13 has an intermediate portion of an engagement release lever 14 formed in an L-shaped flat plate shape. Is pivotally supported.
At one free end of the engagement release lever 14, a pressing portion 15 that presses against the opposing surface of the stopper 6 is formed. A locking hole 16 is formed at the other free end of the engagement release lever 14, and a release cable 17 is provided in the locking hole 16 as indicated by an imaginary line in FIG. It is designed to be locked.
The disengagement lever 14 is always urged by a torsion spring 18 in a direction away from the stopper 6 (clockwise direction in FIG. 2A).

The second bracket 12 is provided with a second pin 21 projecting outward at a right angle to the axis of the cylinder 5, and an intermediate portion of the switch lever 22 is pivotally supported by the second pin 21.
A contact portion 23 that contacts a switch plate 23A (see FIGS. 2A and 2B) projecting from the free end of the stopper 6 is formed at one free end of the switch lever 22. At the other free end of the switch lever 22, a pushing portion 24 that pushes the switch 25 that is installed facing the second bracket 12 is formed.
After the cylinder device 3 is extended to the vicinity of the full stroke and the lowering prevention member 10 is engaged with the engaging portion 7B cut out at the end of the stopper 6, the piston rod 4 is further extended to a certain extent. The contact portion 23 is kicked by the switch plate 23 </ b> A, and the switch lever 22 is rotated to push the switch 25 by the push portion 24.
The switch 25 is configured to stop the drive motor 53A (see FIG. 9) of the pump 53 that supplies pressure oil to the cylinder device 3 when pressed by the pressing portion 24 of the switch lever 22.
FIG. 9 shows a hydraulic circuit diagram of the cab lowering prevention device. In the figure, 51 is a raising side oil passage, 52 is a lowering side oil passage, 53 is a hydraulic pump, 53A is a drive motor, 54 is a tank, 55 Is a switching valve, 55A is a lever, 56 is a pilot check valve interposed in the raising side oil passage 51, and 57 is a pilot check valve interposed in the lowering side oil passage.

As shown in FIG. 3, a pair of chamfered portions 30, 30 are formed on the inner side surfaces of the both side walls at the lower end portion of the stopper 6, as ride-up preventing portions for preventing the ride-up on the buffer member 8. Yes. The double-sided chamfered portion 30 is formed on a tapered surface that forms an angle of attack that gradually widens toward the opening edge of the side wall of the stopper 6.
That is, when the stopper 6 approaches the buffer member 8, the double-sided chamfers 30 and 30 act so as to welcome the buffer member 8, thereby effectively preventing the phenomenon that the stopper 6 rides on the buffer member 8. It is configured.

  Next, the operation of the cabbutyl device and the cab lowering prevention device will be described.

  As shown in FIG. 1, the piston rod 4 of the cylinder device 3 is shortened in a normal state where the cab 1 is not tilted. As shown in FIG. Until the cylinder 5 is covered.

In this state, since the metal stopper 6 has a relatively large weight and is cantilevered at the upper end, the stopper 6 vibrates while the vehicle is running and collides with the metal cylinder 5. Therefore, there is a risk of generating noise.
However, in the present embodiment, since the buffer member 8 is put on the portion of the cylinder 5 that faces the stopper 6, it is possible to prevent the generation of noise.
That is, since the buffer member 8 is formed using a material such as resin, it is possible to prevent noise from being generated by reducing the impact when the stopper 6 collides with the buffer member 8.

When the cab 1 is lifted, if the piston rod 4 extends due to the supply of hydraulic pressure to the cylinder 5 of the cylinder device 3, the stopper 6 follows the piston rod 4 and moves upward with respect to the cylinder 5.
In FIG. 2A, when the engaging portion 7A of the stopper 6 is engaged with the lowering prevention member 10 and the hydraulic pump 53 is stopped, the tilt angle of the cab 1 is about 30 degrees. In FIG. 1, since the center of gravity O ₁ of the cab 1 does not rotate beyond the tilt rotation center P of the cab 1, a compressive load acts on the cylinder device 3. Therefore, the descent prevention member 10 prevents the descent of the stopper 6 and the descent of the cab 1.
Such a cab tilt state is a tilt angle suitable for daily engine inspection work.

When the cab 1 is further tilted and the center of gravity O of the cab 1 is tilted forward of the vehicle beyond the pivot center P of the cab tilt and approaches the maximum tilt angle of 60 degrees (see O ₂ ), the frame side of the stopper 6 The lowering prevention member 10 gets over the protrusion and engages with the engaging portion 7B formed by cutting out the end portion.
When the piston rod 4 further expands, the switch plate 23A shown in FIGS. 2A and 2B comes into contact with the contact portion 23 of the switch lever 22 and rotates the switch lever 22.
Then, the pushing portion 24 shown in FIG. 2C pushes the button of the switch 25 to stop the drive motor 53A of the hydraulic pump 53.
A piston stopper 4B for preventing the movement of the piston 4A is provided at a position where the supply of pressure oil to the cylinder 5A is stopped by the stop of the hydraulic pump (see FIG. 9). When the piston 4A comes into contact with the piston stopper 4B, the piston rod 4 does not extend any further, and the force that the cab 1 tries to fall forward is received by the piston stopper 4B of the cylinder 5, and the cylinder device 3 A tensile load acts on.
When the cab 1 is tilted to a maximum tilt angle of 60 degrees, it is effective when the engine is lowered from the vehicle.

In order to return the cab 1 to the original normal position from the position of the maximum tilt angle, as shown in FIG. 4, the disengagement lever connected to the lever for starting the drive motor 53A of the hydraulic pump 53 14 is pulled in the direction of arrow A to rotate the engagement release lever 14, and the stopper 6 is moved in the direction of arrow B, that is, the engaging portion 7B is moved from the lowering prevention member 10. What is necessary is just to rotate in the direction which leaves | separates. As a result, when the engagement portion 7B of the stopper 6 is disengaged from the lowering prevention member 10, the switch lever 22 is released from the switch plate 23A, and the switch 25 is returned to the original state, and the switch lever 22 is interlocked with the start lever. When the drive switch 53 is turned on and the drive motor 53A is started, pressure oil is supplied to the lower side oil passage 52, and the piston rod 4 moves in the original direction.
After the restraint on the stopper 6 is released in this way, the cab 1 is lowered as the piston rod 4 of the cylinder device 3 is shortened.

  As the piston rod 4 is shortened, as shown in FIG. 5, the stopper 6 translates in the direction of arrow C, and the frame side end of the stopper 6 is moved to the cab side end of the buffer member 8. By moving in the direction of the arrow D when approaching, the stopper 6 is in a state of straddling the buffer member 8.

By the way, when the stopper 6 moves in the direction of the arrow D, if the stopper 6 is not inclined with respect to the buffer member 8, the stopper 6 is a buffer member as shown in FIG. 8 in parallel.
However, when the pressing portion 15 of the engagement release lever 14 comes into contact with the stopper 6 and the stopper 6 is inclined with respect to the buffer member 8 as shown in FIG. One edge of the stopper 6 rides on one side surface of the buffer member 8.
If the stopper 6 moves in the direction of the arrow C while the edge of the stopper 6 rides on the side surface of the buffer member 8, the side surface of the buffer member 8 is damaged by the edge of the stopper 6. Or, since it protrudes to the unexpected position of the stopper, it interferes with surrounding structures.

Therefore, in the present embodiment, a pair of chamfered portions 30 and 30 are formed on the inner side surfaces of both side walls at the lower end portion of the stopper 6, so that when the stopper 6 moves in the direction of arrow D in FIG. Even when 6 is inclined as shown in FIG. 7A, the side surface of the buffer member 8 is prevented from getting on the buffer member 8 so that the side surface of the buffer member 8 is the edge of the stopper 6. To prevent damage from being caused.
That is, by forming the double-sided chamfers 30 and 30 on a tapered surface that forms an angle of attack that gradually widens toward the opening edge of the side wall of the stopper 6, as shown in FIG. When approaching the buffer member 8, the double-sided chamfers 30 and 30 are made to act so as to receive the buffer member 8, and the phenomenon that the stopper 6 rides on the buffer member 8 is effectively prevented.

  According to the embodiment, the following effects can be obtained.

1) By forming a pair of chamfered portions on the inner surface of both side walls at the lower end of the stopper, even if the stopper is tilted when trying to transfer to the buffer member, Since it can be made to act so that a buffer member may be welcomed, the phenomenon that a stopper gets on a buffer member can be prevented.

2) By preventing the stopper from riding on the buffer member, it is possible to prevent the occurrence of a harmful effect that the edge of the stopper caused by the stopper riding on the buffer member damages the side surface of the buffer member.

3) Covering the outer periphery of the cylinder with a cushioning member can prevent the occurrence of noise due to the collision between the metal cylinder and the stopper, thus improving the performance of the cabylt device and the cab lowering prevention device. .

  FIG. 8 shows another embodiment of the climbing prevention chamfer.

In the second embodiment shown in FIG. 8A, a climbing prevention chamfered portion 31 is disposed at the cab side end portion of the buffer member 8, and the climbing prevention chamfered portion 31 is disposed on the cab side. It is formed in a tapered shape that gradually becomes thinner as it goes.
The climbing prevention chamfered portion 31 according to the present embodiment also acts to welcome the stopper 6 when the stopper 6 is inclined when the stopper 6 is about to transfer to the cushioning member 8. The phenomenon of getting on can be prevented.

In the third embodiment shown in FIG. 8 (b), the climbing prevention chamfered portion 32 is disposed at the cab side end portion of the cushioning member 8. The cab side end is formed with a reduced diameter.
Since the climbing prevention chamfered portion 32 according to the present embodiment also acts to receive the stopper 6 when the stopper 6 tilts when the stopper 6 is about to transfer to the cushioning member 8, the stopper 6 acts as the cushioning member. The phenomenon of getting on can be prevented.

In the fourth embodiment shown in FIG. 8 (c), the ride-up preventing chamfered portion 33 is disposed at the cab side end portion of the cushioning member 8, and the ride-up preventing chamfered portion 33 is arranged on the stopper 6 side. It is formed in a tapered shape that gradually becomes thinner as it goes to.
The ride-up preventing chamfered portion 33 according to the present embodiment also acts to receive the stopper 6 when the stopper 6 is inclined when the stopper 6 is about to transfer to the buffer member 8. The phenomenon of getting on can be prevented.

It is a side view which shows the carbylate apparatus provided with the cab descent | fall prevention apparatus which is one embodiment of this invention. 1 shows a cab lowering prevention device according to an embodiment of the present invention, in which (a) is a side view, (b) is a sectional view taken along line bb in (a), and (c) is in (b). It is a partially abbreviated arrow line view along cc line. The stopper is shown, (a) is a front view, (b) is a partially omitted cross-sectional view along the line bb of (a). It is a side view which shows the time of expansion | extension of the cab descent | fall prevention apparatus which is one embodiment of this invention. It is a partially omitted side view for explaining the riding-up preventing action. FIGS. 6A and 6B are cross-sectional views in the case of a comparative example corresponding to a cross-sectional view taken along the line YY in FIG. 5, in which FIG. Similarly, it is sectional drawing in the case of this Embodiment, (a) shows before transfer, (b) has shown after transfer. The other embodiment of a climbing prevention chamfer part is shown, (a) is a side view of 2nd embodiment, (b) is a side view of 3rd embodiment, (c) is 4th. It is sectional drawing equivalent to (a) of FIG. 7 of embodiment. It is a hydraulic circuit diagram of the cab lowering prevention device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cab, 2 ... Frame, 3 ... Cylinder device, 4 ... Piston rod, 4A ... Piston, 4B ... Piston stopper, 5 ... Cylinder, 6 ... Stopper, 7A, 7B ... Engagement part, 8 ... Buffer member, 10 ... Lowering prevention member, 11 ... first bracket, 12 ... second bracket, 13 ... first pin, 14 ... engagement release lever, 15 ... pressing part, 16 ... locking hole, 17 ... cable for release, 18 ... torsion Spring, 21 ... second pin, 22 ... switch lever, 23 ... contact portion, 23A ... switch plate, 24 ... pressing portion, 25 ... switch, 30, 31, 32, 33 ... chamfered portion (climbing prevention portion), 51 ... Raising side oil passage, 52 ... Lower side oil passage, 53 ... Hydraulic pump, 53A ... Drive motor, 54 ... Tank, 55 ... Switch valve, 55A ... Lever, 56 ... Pilot check valve, 57 ... Pilot reverse Valve.

Claims (3)

A cylinder device interposed between the cab and the frame; a stopper pivotally attached to an end of a piston rod pivotally attached to the cab side of the cylinder device; and the cylinder device A lowering prevention member disposed in the vicinity of the stopper moving region to prevent the stopper from moving toward the frame, and to reduce the impact when the stopper collides with the cylinder device to prevent noise generation. In the cab lowering prevention device provided with a buffer member that
A cab lowering prevention device is provided between the stopper and the cushioning member, wherein a climbing prevention unit for preventing the stopper from climbing onto the cushioning member at the frame side end portion is provided.   The riding-up preventing portion is configured by a pair of chamfered portions formed on inner side surfaces of both side walls at the frame side end portion of the stopper, and the pair of chamfered portions are formed on opening edges on both side walls of the stopper. 2. The cab descending prevention device according to claim 1, wherein the cab descending prevention device is formed on a tapered surface that forms an angle of attack that gradually widens as it goes.   The riding-up preventing portion is configured by a chamfered portion formed on an outer peripheral surface at the cab side end portion of the buffer member, and the chamfered portion becomes gradually narrower as the distance from the opening edge on both side walls of the stopper increases. The cab lowering prevention device according to claim 1, wherein the cab lowering prevention device is formed on a tapered surface.

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