JPS638708Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety device for a self-propelled crane.

As shown in Fig. 1, the self-propelled crane has a swivel base 2 mounted on a vehicle 1 so that it can be rotated freely, and a boom 3 is disposed on this swivel base 2 so that its elevation can be adjusted freely. Crane work is carried out by hoisting cargo and raising and lowering a boom 3 and turning (by rotating a swivel base 2). In FIG. 1, 4 is a hydraulic cylinder for adjusting the elevation of the boom 3, 5 is a hydraulic motor for adjusting the swing of the boom 3, and 6 is the vehicle 1.
A pair of outrigger jacks are installed on the left and right sides of the front and back. The lifting capacity of this type of self-propelled crane depends on the stability of the vehicle 1, the lifting angle of the boom 2, and the lifting capacity of the boom 2.
length (if boom 2 is a telescoping boom, the amount of telescoping)
Varies depending on. The stability of the vehicle 1 described above differs depending on whether the outrigger jack 6 is grounded or not, and the direction in which the boom turns with respect to the vehicle 1. In the case of a self-propelled crane for rough terrain as shown in FIG. The height is lowest when the boom 3 is pivoting in the side areas of the boom 3, and therefore the lifting capacity in the front or rear areas is greater than that in the side areas. In a self-propelled crane that has different lifting capacities for each swing area, when carrying out crane work by swinging the boom 3 forward or backward to lift a load that exceeds the lifting capacity of the side areas, the crane If the swivel base 2 inadvertently rotates for some reason and the boom 3 swivels to the side, the self-propelled crane will fall. The careless turning of the swivel base 2 occurs due to malfunction of the swing hydraulic motor 5 (oil leakage, etc.) as well as erroneous operation by the crane operator. Therefore, when performing crane work in such conditions, a releasable swing fixing device consisting of a swing brake or pin connection means (not shown) is provided, and the swing fixing device is operated to rotate the swivel base 2. Crane work is carried out after disabling the swinging movement and, ultimately, the swinging movement of the boom 3. However, the crane operator sometimes forgets to operate the swing fixing device itself, and it is not possible to completely avoid careless swinging movements, so there is always a risk of the self-propelled crane falling over.

The present invention has been developed in view of the above points, and the boom 2 is rotated to a boom rotation area with a high lifting capacity (in the embodiment shown in FIG. 1, the front or rear area), thereby increasing the lifting capacity. When performing crane work by lifting a load that exceeds the lifting capacity in a low swing area (in the embodiment shown in FIG. If the boom has not been operated to disable it, it will alert the crane operator that he or she has forgotten to operate the swing locking device or that it is dangerous to swing the boom, thereby preventing a self-propelled crane from falling over. This is what we are trying to prevent.

An embodiment in which the present invention is applied to the self-propelled crane shown in FIG. 1 will be described below with reference to FIG. 2. Second
In the figure, 7 is a limit switch that operates and closes when the actual lifting load reaches the limit lifting capacity in the boom rotation area, ie, the side area, where the lifting capacity is low. (This limit switch 7 constitutes a lifting limit signal generating means in the scope of the utility model registration claims.) Reference numeral 9 denotes a swing area detection switch that is activated and closed when the boom 2 swings to a swing area with high lifting capacity, that is, a front area or a rear area. Alternatively, it is provided on the vehicle 1 side or the turning base 2 side opposite to a cam (not shown) provided on either side of the vehicle 1 (this turning area detection switch 9 is required for utility model registration). ). 1
0 is a swing fixing detection switch that operates and closes when the above-mentioned swing fixing device is released, and when the swing fixing device is a brake, it operates in response to operation of the brake lever or brake pedal. When the rotation fixing device is a pin connecting means, it is configured to operate in response to insertion and removal of the pin.

11 stores the limit lifting capacity in the swing area where lifting capacity is low, that is, the side area, for each boom length and each boom hoisting angle, and also stores the boom length based on the actual boom length and boom hoisting angle. This is a limit signal generator that receives the signal l and the boom hoisting angle signal θ and outputs the limit lifting capacity signal WM in the boom state at that time. A comparator 12 receives the limit signal WM from the limit signal generator 11 and the load signal W based on the actual lifting load, and outputs an electric signal when the lifting load signal W reaches the limit signal WM. 13 is a transistor that operates upon receiving the electrical signal from the comparator 12. transistor 13
is interposed in the electric circuit of the relay 10, and as a result, the limit switch 7 is, as described above,
When the actual lifting load reaches the limit lifting capacity in the boom swing area where the lifting capacity is low, that is, the side swing area, it will be activated and closed. The limit lifting capacity may be stored in the limit signal generator 11 as a value corresponding to the limit lifting load, or may be stored in the limit signal generator 11 as a value corresponding to the limit lifting load.
It may also be stored as the critical moment of . In the latter case, the load signal W entering the comparator becomes the boom moment signal actually acting on the boom. 14 is a buzzer, and 15 is a power source. The power source 15, the rotation area detection switch 9, the limit switch 7, the rotation fixation detection switch 10, and the buzzer 14 are each connected in series.

Next, the action will be explained. If the boom 3 is swiveled to a swing area with a large lifting capacity, that is, a front or rear area, and a lifting load that exceeds the limit lifting capacity is lifted in a swing area with a low lifting capacity, that is, a side area, the swing area Detection switch 9 and limit switch 7 are activated and closed. On the other hand, if the rotation fixing device does not lock the rotation movement of the swivel base 2 and thus the boom 3, the rotation fixation detection switch is activated and closed, and the buzzer 14 issues an alarm. In this state, operate the swing fixing device to rotate the swing base 2 and the boom 3.
If the rotation movement is locked, the rotation fixed detection switch 1
0 is not activated and opens, the alarm from the buzzer 14 is cut off. When lifting a load that is less than the limit lifting capacity in the swing area with low lifting capacity, that is, in the side area, the limit switch 7 becomes inactive and opens, so the swing fixing device does not have to lock the swing movement of the swing base. Buzzer 14 does not alarm. In other words, in this state, there is no risk that the self-propelled crane will fall even if the swivel base 2 and therefore the boom 3 are swiveled to the side area.

Since the present invention is configured and operates as described above, in a work situation where an inadvertent turning movement of the boom 2 may cause a fall accident, an alarm will be issued if the turning movement of the boom 2 is not fixed by the turning fixing device. This can prevent accidents involving overturning of type cranes.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a self-propelled crane, and FIG. 2 is an explanatory diagram of a safety device for the self-propelled crane of the present invention. Vehicle...1, Swivel base...2, Boom...3, Limit switch...7, Turning area detection switch...
9. Rotating fixed detection switch...10. Alarm (buzzer)...14.

Claims (1)

[Scope of utility model registration request] A self-propelled vehicle comprising a vehicle, a swivel platform mounted on the vehicle so as to be adjustable in its swivel movement and configured to fix its swivel motion by a releasable swivel locking device, and a boom disposed on the swivel platform in a manner adjustable in elevation. A crane safety device that generates an electrical signal when the actual lifting load reaches the limit lifting capacity in a boom rotation area with low lifting capacity, and a lifting limit signal generating means that generates an electric signal when the boom turns in a high lifting capacity. turning area signal generating means for generating an electric signal when turning into the area;
A swing fixing detection switch and an alarm are provided, which are activated when the swing fixing device is in a released state, and the lifting limit signal generating means and the swing area signal generating means generate an electric signal, and the swing fixing detection switch is activated. A safety device for a self-propelled crane, characterized in that the alarm is configured to operate when activated.