JP2000006853A - Cab tilt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weight of a cab tilt device by preventing lowering of a cab even when a mechanical cab lowering preventive device is eliminated. SOLUTION: A stay 11 is supported free to slide by a slide guide 10 on a cylinder 5 of a cylinder device 4 interposed between a cab 1 and a frame 2 and to tilt the cab, and an upper end part of the stay 11 is connected to a head end part of a piston rod 6 of the cylinder device. A stop switch 25 to maintain stopping of an electric motor of the cylinder device 4 is arranged on an upper end part of the cylinder 5, a stop lever 17 to actuate the stop switch 25 by revolving at the time when a sliding end part 18 is positioned at a first inclined surface part 13 of the stay 11 is supported on the upper end part of the cylinder 5, and a release lever 21 is linked to the stop lever 17. Consequently, it is possible to prevent lowering of the cab, accordingly, to eliminate a mechanical cab lowering preventive device and to reduce weight and cost of a cab tilt device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cab tilt device for tilting a cab by lifting the cab with a cylinder device in a cab-over type vehicle.

[0002]

2. Description of the Related Art In general, a cab-over type automobile is constructed so that maintenance and inspection work of an engine portion can be easily performed by lifting and tilting a cab.
In this case, since the cab is heavy, a cab tilt device is used in which a cylinder device is interposed between the cab and the vehicle body (frame), and the cab is tilted by the expansion and contraction operation of the cylinder device. Sometimes.

In this cab tilt device, a mechanical cab lowering prevention device is additionally provided in order to avoid the danger of the cab being lowered when a failure occurs in the cylinder device. The mechanical cab lowering prevention device includes a stay pivotally attached to the upper end of the piston rod of the cylinder device, a plurality of teeth cut into the stay, and a lock lever pivotally attached to the cylinder of the cylinder device and meshing with the teeth. And
If the piston rod starts to descend due to a failure of the hydraulic circuit or the like, the lock lever meshes with the nearest tooth of the stay to prevent the piston rod from descending.

[0004]

However, there is a problem that the mechanical cab lowering prevention device needs to be constructed robustly to support a heavy cab, and the weight becomes heavy.

An object of the present invention is to provide a cab tilt device which can prevent the cab from lowering even if the mechanical cab lowering prevention device is omitted.

[0006]

A cab tilt device according to the present invention is a cab tilt device wherein the cab is tilted by a cylinder device interposed between the cab and the frame. A stay is slidably supported by a slide guide on the outside of the cylinder, and an upper end of the stay is connected to a tip end of a piston rod of the cylinder device. A stop switch for maintaining the stop of the driving device of the apparatus is provided, and the stop switch is configured to maintain the stop of the driving device by detecting a lower end portion of the stay.

According to the above-described means, when the piston rod of the cylinder device is extended to support the cab, the stop switch detects the lower end of the stay to maintain the stop of the drive device of the cylinder device. As a result, the cab can be prevented from lowering.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

The cab tilt device according to the present invention is interposed between the cab and the vehicle body (frame) as shown in FIG. 3 so as to perform a cab tilt operation. That is, the cab tilt device 3 includes a cylinder device 4 interposed between the cab 1 and the frame 2, and the cylinder device 4 includes a lost motion link lever device 7 in which the upper end of the piston rod 6 is mounted on the cab 1.
The lower end of the cylinder 5 is rotatably supported on the frame 2 by a pin 9.

As shown in FIGS. 1 and 2, a slide guide 10 formed in a channel shape is arranged at the upper end of the cylinder 5 so as to straddle the cylinder 5 and is fixed by welding or the like. A stay 11 is inserted between the inner periphery of the slide guide 10 and the outer periphery of the cylinder 5 and is slidably supported. The stay 11 is formed in a slender plate shape by a metal or a resin having appropriate strength, and an upper end of the stay 11 is rotatably mounted on a pin 8 at an upper end of the piston rod 6. Therefore, the stay 11 is guided by the slide guide 10 in accordance with the expansion and contraction operation of the piston rod 6 and linearly moves. On one end of the stay 11, a sliding surface 12 on which a sliding end 18 of a stop lever 17 slides and slides is formed. An inclined surface portion (hereinafter, referred to as a first inclined surface portion) 13 for rotating from the 11 side is formed. An inclined surface portion (hereinafter, referred to as a second inclined surface portion) 14 for increasing the amount of rotation of the stop lever 17 is formed on the end of the stay 11 opposite to the sliding surface 12.

A bracket 15 is disposed at a position perpendicular to the slide guide 10 at the upper end of the cylinder 5 and is fixed by welding or the like. The bracket 15 has a stop lever 17 formed in a substantially ratchet pawl shape. One end is pivotally supported by a pin 16. A sliding end 18 that slides on the sliding surface 12 of the stay 11 is formed at an upper end, which is a free end of the stop lever 17. One end of a spring 19 is locked to the stop lever 17, and the other end of the spring 19 is
Is locked to a locking member 20 fixed to the opposite side.
The spring 19 always biases the stop lever 17 in the direction in which the sliding end 18 slides on the sliding surface 12 of the stay 11, and the sliding end 18 of the stop lever 17 By being urged at 19, the stay 11 is pressed against the sliding surface 12.

The pin 16 pivotally supporting the stop lever 17 has L
A letter-shaped release lever 21 is rotatably supported at an intermediate portion thereof, and the release lever 21 is constantly urged in a counterclockwise direction in FIG. An operation side end 22a, which is one free end of the release lever 21, faces an intermediate portion of the stop lever 17 so that the engagement with the first inclined surface portion 13 of the stay 11 can be released. A cable 24 is locked to a force point side end 22b which is the other free end of the release lever 21.
Reference numeral 4 denotes a configuration in which an external force is urged by human power or a mechanical force of an actuator or the like to rotate the release lever 21 against the spring 23.

A stop switch 2 is provided on a side surface (hereinafter referred to as a back surface) of the cylinder 5 which is perpendicular to the slide guide 10.
5, a stop plate 27 fixed to the detector 26 of the stop switch 25 while projecting from the stop lever 17 is brought into contact with the detector. Stop plate 2
Since 7 is fixed to the stop lever 17, it is substantially integral with the stop lever 17. The stop plate 27 is moved only when the sliding end 18 of the stop lever 17 is fully rotated to the lowest position of the first inclined surface 13 of the stay 11.
The stop switch 25 is set so as to come into contact with the detector 26. The stop switch 25 is set so as to maintain the stop of the electric motor that drives the hydraulic pump of the cylinder device 4 when the stop plate 27 contacts the detector 26. On one side of the stop switch 25, a stopper 28 that defines a movement limit of the stop plate 27 is fixed.

A stroke switch 29 is provided on the bottom surface of the cylinder 5 opposite to the slide guide 10, and a stroke plate 31 fixed to the piston rod 6 faces a detector 30 of the stroke switch 29. ing. Since the stroke plate 31 is fixed to the piston rod 6, the stroke plate 31 is configured to move integrally with the expansion and contraction operation of the piston rod 6. The stroke plate 31 detects the detector 30 of the stroke switch 29 only when the piston rod 6 is fully shortened.
Is set to abut. The stroke switch 29 is set to stop the electric motor that drives the hydraulic pump of the cylinder device 4 when the stroke plate 31 contacts the detector 30.

As shown in FIG. 5, a hydraulic drive circuit 40 of the cylinder device 4 includes an upside oil supply / discharge passage (hereinafter, referred to as an upside oil passage) 41 and a downside supply / discharge oilway (hereinafter, referred to as an upside oil passage). , A hydraulic pump 43 driven by the electric motor M, a tank 44, and a switching valve 45. The up-side oil passage 41 is fluidly connected to the frame-side pressure chamber of the cylinder 5, and the down-side oil passage 42 is fluidly connected to the cab-side pressure chamber of the cylinder 5.

The switching valve 45 is a four-port, two-position, manually operated switching valve.
1 is connected to the hydraulic pump 43 side, and the lower oil passage 42 is connected to the tank 44 side. When not in use, the upper oil passage 41 is connected to the tank 44 and the lower oil passage 42 is connected to the hydraulic pump 43. Side. Further, the first pilot check valve 46 and the second pilot check valve 4
7, a first throttle valve 48 and a second throttle valve 49 are interposed respectively. The first pilot check valve 46 and the second
Each of the pilot check valves 47 is configured to prevent a flow from the cylinder 5 side to the switching valve 45 side at a predetermined pressure or less.

Next, the operation of the cab tilt device according to the above configuration will be described.

In the normal state of the cab 1 such as during running,
In the cab tilt device 3, the piston rod 6 of the cylinder device 4 is shortened as shown in FIGS. 1 and 2, and the stay 11 is inserted into the slide guide 10 up to its base. The hydraulic drive circuit 40 is in the state shown in FIG.

For maintenance and inspection work of the engine part,
When the cab 1 is tilted by the cab tilt device 3, the switching valve 45 is switched to the up side in the hydraulic drive circuit 40 shown in FIG. 5 to supply hydraulic pressure to the cylinder 5 of the cylinder device 4. , The piston rod 6 is extended as shown in FIG.
At this time, the sliding end 18 of the stop lever 17 is moved up along with the extension of the piston rod 6 so that the sliding surface 1 of the stay 11 moves upward.
Slide 2.

The stay 11 rises together with the piston rod 6, and the sliding end 18 of the stop lever 17 is provided at the lowest part of the first inclined surface 13 of the stay 11 as shown in FIG. Stop plate 27 detects the detector 26
, The stop switch 25 is pressed to operate.

At this time, the second inclined surface portion 14 of the stay 11 falls into the slide guide 10 as shown in FIG.
The sliding end 18 of the stop lever 17 is moved in the direction away from the sliding end 18 of the
And the second inclined surface portion 14 is lowered, and the amount of rotation of the stop lever 17 is increased accordingly. That is, the amount by which the stop lever 17 is pushed into the detector 26 is increased, and the stop switch 25 is reliably operated.

The operation of the stop switch 25 by the pushing operation of the stop lever 17 causes the hydraulic pump 4 of the cylinder device 4 in the hydraulic drive circuit 40 shown in FIG.
3 is stopped, and the cylinder device 4 is stopped.
Of the piston rod 6 is stopped. When the electric motor M is stopped, the stop switch 25 is turned on by the stop lever 1
Since the piston rod 6 of the cylinder device 4 is maintained as long as the piston rod 6 is pushed, accidental shortening of the piston rod 6 of the cylinder device 4 is reliably prevented. That is, when the hydraulic pump 43 is stopped, the first pilot check valve 16 prevents the hydraulic oil from being discharged from the frame-side pressure chamber of the cylinder 5, so that the cab 1 is reliably prevented from lowering. ing.

When the cab is lowered after maintenance and inspection work, the cable 24 is pulled by an operator or the like. When the cable 24 is pulled, the release lever 21 is rotated and the stop lever 17 is rotated clockwise in FIG. 3, so that the stop plate 27 of the stop lever 17 presses the detector 26 of the stop switch 25. Cancel. When the stop operation of the stop switch 25 is released in this way, the electric motor M of the cylinder device 4 is ready to be started. Therefore, when the switching valve 45 is switched to the lower side by the operator and a cab lowering command is issued to the cylinder device 4 by the operator, the electric motor M is started and the cab side pressure chamber in the cylinder 5 of the cylinder device 4 is activated. , The piston rod 6 of the cylinder device 4 is shortened.

When the stroke plate 31 fixed to the piston rod 6 comes into contact with the detector 30 of the stroke switch 29 by the shortening operation of the piston rod 6, the stroke switch 29 is turned on by the hydraulic pump 4 of the cylinder device 4.
3 is stopped. In this state, the cab tilt device 3 has the piston rod 6 of the cylinder device 4 shortened as shown in FIGS. 1 and 2, and the stay 11 is in a state of being inserted into the slide guide 10 almost to its base. I have. Therefore, the cab tilt device 3 has returned to a normal state such as running.

By the way, for example, the first of the cylinder devices 4
Even if it is assumed that the piston rod 6 slightly contracts due to oil leakage from the pilot check valve 46, the sliding end portion 18 of the stop lever 17 slides on the first inclined surface portion 13 so that the stop lever 17 is the stay 11 side from FIG.
(C), (b), and (a), the stop lever 17 is prevented from being broken by the accidental shortening operation of the piston rod 6, that is, the stay 11, since the stop lever 17 is rotated clockwise.

In addition, the stop lever 17 is moved to the first inclined surface portion 1.
As long as the stop switch 25 keeps the stop operation as long as the stop switch 25 does not rotate by the drop of the third drop and the drop of the second inclined surface portion 14,
The electric motor M maintains the forced stop state. Therefore, safety is sufficiently ensured even if a mechanical cab lowering prevention device is not provided.

As described above, according to the present embodiment, since the cab can be prevented from lowering, the weight of the cab tilt device can be reduced by omitting the mechanical cab lowering prevention device. Thus, the fuel efficiency of the cab-over type vehicle can be reduced, and the manufacturing cost of the cab-over device and hence the cab-over type vehicle can be reduced.

The stop lever 17 rotates and the stop switch 2
When the stop lever 5 is operated, the sliding end 18 of the stop lever 17 is lowered by the drop of the first slope 13 and the drop of the second slope 14, so that the amount of rotation of the stop lever 17 is increased. Therefore, the stop lever 17 can be operated reliably by pushing the detector 26 greatly. Therefore, by using a limit switch having relatively low sensitivity as the stop switch 25, the cost can be further reduced.

Even if the piston rod 6 is slightly shortened when the cab 1 is tilted, the stop lever 17
When the stop end 17 is rotated from the stay 11 side by sliding the sliding end portion 18 of the first inclined surface portion 13, the stop lever 17 is inadvertently shortened of the piston rod 6, that is, the stay 11. It will not be damaged by operation.

Further, the stop lever 17 is moved to the first inclined surface portion 1.
As long as the stop switch 25 keeps the stop operation as long as the stop switch 25 does not rotate by the drop of the third drop and the drop of the second inclined surface portion 14,
The electric motor will maintain the forced stop state. Therefore, safety is sufficiently ensured even if a mechanical cab lowering prevention device is not provided.

The present invention is not limited to the above embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.

For example, the release lever may be configured to be operated by a lowering command to the cylinder device.

[0033]

As described above, according to the present invention,
Since the cab can be prevented from lowering even if the mechanical cab lowering prevention device is omitted, the weight of the cab tilt device can be reduced, and the manufacturing cost of the cab tilt device and thus the cab-over type vehicle can be reduced. it can.

[Brief description of the drawings]

FIG. 1 shows a cab tilt device according to an embodiment of the present invention, wherein (a) is a front view and (b) is a bottom view.

2A is a plan view, FIG. 2B is a rear view, and FIG.
Is a side view.

FIGS. 3A and 3B show a tilted state of the cab, wherein FIG. 3A is a schematic front view, and FIG. 3B is a front view showing a portion b of FIG.

FIGS. 4 (a), (b), and (c) are front views, each partially omitted and partially cut away, for explaining the operation.

FIG. 5 is a circuit diagram showing a hydraulic circuit of the cylinder device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cab, 2 ... Frame, 3 ... Cab tilt device, 4
... Cylinder device, 5 ... Cylinder, 6 ... Piston rod,
7 ... Lost motion link lever device, 8 ... Pin, 9
... pins, 10 ... slide guides, 11 ... stays, 12 ...
Sliding surface, 13: first inclined surface portion, 14: second inclined surface portion, 1
5 bracket, 16 pin, 17 stop lever, 18
... Sliding end, 19 ... Spring, 20 ... Locking member, 21
... release lever, 22a ... working side end, 22b ... point of force side, 23 ... spring, 24 ... cable, 25 ... stop switch, 26 ... detector, 27 ... stop plate, 28 ... stopper, 29 ... stroke switch, 30 ... detector, 3
1: Stroke plate, 40: Hydraulic drive circuit, 41:
Upside oil supply / discharge passage, 42 Downside oil supply / discharge passage, 43 hydraulic pump, 44 tank, 45 switching valve, 46 first pilot check valve, 47 second pilot check valve, 48 ... First
Throttle valve, 49 ... second throttle valve.

Claims (4)

[Claims] 1. A cab tilt device in which a cab is tilted by a cylinder device interposed between a cab and a frame, wherein a stay slides outside a cylinder of the cylinder device by a slide guide. While being freely supported,
An upper end of the stay is connected to a distal end of a piston rod of the cylinder device, and a stop switch for maintaining a stop of the driving device of the cylinder device is provided at an upper end of the cylinder. A cab tilt device, wherein the switch is configured to maintain the stop of the driving device by detecting a lower end portion of the stay. 2. A stop lever rotatably supported on an upper end of the cylinder, the stop lever being turned when the free end slidingly contacting the stay is positioned at the lower end of the stay to operate the stop switch. 2. The cab tilt apparatus according to claim 1, wherein said stop lever is associated with release means for releasing the engagement between said stop lever and said stop switch. 3. The cab tilt device according to claim 2, wherein an inclined surface portion for rotating the stop lever from the stay side is formed at a lower end portion of the stay. 4. An inclined surface for enlarging the amount of rotation of said stop lever is formed on a sliding contact surface of said stay at a lower end portion thereof with said slide guide. Cab tilt equipment.