1. Field of the Invention
The present invention relates to the structure of overhead lamp and mounting bracket for constructional vehicle. More particularly, the overhead lamp with mounting bracket installed on a roof of the constructional vehicle has capable to control the illuminating direction by adjusting the tilt angle. A pair of arc-slits disposed at lateral surfaces of the mounting bracket has adopted for tiling and securely fixing the lamp at a controlled position.
2. Description of the Related Art
As generally known, a constructional vehicle has equipped with a pair of overhead lamps to secure the front views, while the vehicle is operating at night or in a dark place such as a tunnel. The overhead lamp has assembled with a lamp chamber consisted a main housing and a transparent cover, sub-housing consisted lens and reflecting mirror and mounted in the lamp chamber, and a head-lamp unit mounted in the sub-housing.
The overhead lamp unit comprises a bulb as a light source, and a bulb adaptor that supports the bulb. For the bulb, the halogen bulb is generally used for adopting temperature radiation system. Alternatively, a gas discharge bulb is adopted a luminescence system.
The halogen bulb is relatively darker than the gas discharge bulb since it has a low luminous flux, but is cheaper and therefore generally applied to mid and low-end cars. On the other hand, although being expensive, the gas discharge bulb is even brighter than the halogen bulb since having a high luminous flux, and therefore is generally applied to high price cars.
Recently, researches for headlamp assemblies using an LED lamp as the light source have been actively performed.
Especially, the LED lamp is advantageous in terms of general aspects including a processing rate, power consumption and the lifespan owing to its properties as a semiconductor, and therefore has been widely used as an electronic indication part in various electronic appliances. Furthermore, as high-brightness LEDs are introduced recently, the LED lamp has been spotlighted as a high-tech future light source. The LED lamp is not only power-saving in comparison with other conventional bulbs, but also achieves excellent color rendering in comparison with conventional color lighting using glasswork, coating, a filter and so on, since having elements of a variety of colors. In addition, the LED lamp has a great durability. Therefore, the maintenance cost and the replacement cost for the vehicle headlamp assembly can be reduced.
FIG. 1 is a perspective view showing a pair of overhead lamps mounted on a heavy equipment or constructional vehicle.
Referring to FIG. 1, since the overhead lamp has a high brightness and excellent durability as described above, the LED lamp is generally used to a heavy equipment vehicle 2 in a constructional site, that is a poor environment, or an off-road vehicle (not shown) such as a jeep.
FIG. 1 shows the heavy equipment vehicle 2 mounted with a lamp apparatus 6 at an upper surface of a roof panel 4 thereof. The appearance of the lamp apparatus 6 is constituted by a hexahedral case 8. In the center of a lower surface of the case 8, a fixed rod 10 is fixed to the roof panel 4, being equipped with a connection bolt 12 at a lower end thereof.
The conventional lamp apparatus 6 is immovably fixed to the upper surface of the roof panel 4. However, it is disadvantageous to fix the lamp apparatus 6 to the roof panel 4 in an angle-uncontrollable state because the lamp apparatus 6 would illuminate different positions according to the working positions by the heavy equipment vehicle 2.
For example, more specifically, in case of excavating the ground or a wall, the lamp apparatus 6 needs to have totally different illumination angles to adequately function. That is, when the lamp apparatus 6 is immovably fixed to the upper surface of the roof panel 4, the working areas can not be properly illuminated.
Accordingly, a structure for supporting a lamp apparatus has recently been developed as shown in FIGS. 2 and 3.
FIG. 2 is an exploded perspective view of the lamp apparatus supporting structure for a vehicle according to another conventional art. FIG. 3 is a side view of the lamp apparatus supporting structure of FIG. 2, showing an illumination angle range.
Referring to the drawings, another conventional lamp and supporting structure, a lamp apparatus 106 comprises a main case 108 equipped with a plurality of LED lamps (not shown) mounted therein. The main case 108 includes a connection hole 112 on both sides, and a front cover 110 at the front. In addition, a connection protrusion 114 is formed on a lower rear surface of the main case 108.
The main case 108 is fixed to the roof panel 4 of the heavy equipment vehicle 2, and a fixing unit 120 for controlling the illumination angle is additionally provided. The fixing unit 120 comprises a center supporter 122 fixed to the roof panel 4 apart from a lower part of the main case 108, and side supporters 124 vertically extended upward from both ends of the center supporter 122 and brought into close contact with lateral sides of the main case 108. A hinge hole 126 is formed at each side supporter 124, corresponding to the connection hole 112.
The center supporter 122 has a penetration hole 218 substantially in the middle. In addition, a position determining rib 130 is extended from a rear side of the center supporter 122 as seen from the front to the rear of the vehicle. More specifically, the position determining rib 130 is bent in a regular arc form upward from the center supporter 122, and includes a position determining slit 142 formed in a length direction thereof.
A washer 136, a nut 134 and a fixing bolt 132 are sequentially connected through the penetration hole 128 of the center supporter 122, thereby connecting the center supporter 122 to the upper surface of the roof panel 4 (FIG. 1).
In a state where the connection holes 112 formed on the main case 108 and the hinge holes 126 formed on the side supporter 124 are correspondingly connected to each other, a washer 140 and a hinge bolt 138 are sequentially connected to the connection holes 112 through the hinge holes 126. Therefore, the main case 108 is rotationally hinged on the fixing unit 120.
Next, when the connection protrusion 114 of the main case 108 is engaged with the position determining slit 142 of the position determining rib 130 formed at the fixing unit 120 and a position fixing lever 141 is connected to the connection protrusion 114, the main case 108 can be rotated with respect to the fixing unit 120 fixed to the roof panel 4 of the vehicle. Accordingly, the illumination angle of the LED lamps (not shown) provided in the main case 108 can become controllable as shown in FIG. 3.
According to the above-described conventional lamp apparatus supporting structure for a vehicle, however, since a displacement range of the illumination angle of the main case 108 is restricted within the length of the position determining slit 132, the actual illumination angle is approximately 10˜12 degrees as shown in FIG. 3.
Moreover, since the conventional lamp apparatus supporting structure is supported by 3 points, that is, both sides of the main case 108 and the connection protrusion 114 formed at the rear middle part of the main case 108, it is difficult to securely fix the main case 108 with respect to the fixing unit 120. More specifically, while the heavy equipment vehicle 2 is moving to work in such a poor work environment, the position fixing lever 141 fixed merely by one position may be unfastened, thereby hindering the normal performance of the lamp apparatus.
Meanwhile, considering that the conventional lamp apparatus supporting structure is mainly applied to the heavy equipment vehicle which works at a poor environment such as a construction site generating much vibration with an uncompleted underground construction, the hinge bolt 138 would be transmitted with the vibration of the vehicle and easily separated from the connection hole 112 of the main case 108. As a result, unwanted change of the illumination angle of the lamp apparatus 6 may be caused.