TITLE OF THE INVENTIONA Lamp for Construction Work Using a Light SourceHaving DirectivityBACKGROUND OF THE INVENTIONField Of the InventionThe present invention relates to a lamp for construction work, and more particularly, it is concerned with a lamp for construction work using a light source having directivity such as an LED (light-emitting diode).
Description of the Background ArtA lamp for construction work is used for notifying drivers and the like of an area where road work is under way as a danger zone. In general, lamps for construction work use a dry battery for road signs as a power supply, and also use an optical sensor to automatically emit a flashing signal as it becomes dark for notifying people of the danger zone. Most conventional lamps for construction work have used light bulbs as the light source, however, these bulbs have problems such as frequent burnout and a large power consumption. Therefore, recently an LED has become more popular.
While burnout is unlikely to occur and the power consumption is small, the LED is dim because of a weak emission amount and a strong directivity of light.
Fig. 6 is an overall perspective view of a conventional lamp for construction work, Fig. 7 is a cross section viewed from line VII-VII in Fig. 6, and Fig. 8 is a cross section viewed from line VIII-VIII of Fig. 6.
With reference to these figures, a lamp for construction work 1 is mounted by fixing a cap 9 which is provided in the lower part of the lamp to a pole for construction work 27. A battery 29 is attached under cap 9 for supplying an electric power to each of LED 31a-31h through codes 21. LED is provided on both sides of a board 15. More specifically, LED 31a, 31c, 31e, 31g are provided on the right surface, and LED 31b, 31d, 31f, 31h are provided on the left surface of board 15 in Fig. 7.
Each LED is connected with each other by a printed wiring provided on board 15. By flashing each LED for each surface of board 15, light is emitted outwardly through housings 3a and 3b which are made of transparent plastic.
As can be seen in Fig. 7, LED 31g and 31e emit light flux 35g and 35e to irradiate the right side of the drawing, while LED 31h and 31f emit light flux 35h and 35f to irradiate the left side of the drawing. Therefore, a degree of visual recognition of the lamp for construction work from both sides is improved.
In the above-described conventional lamp for construction work, it is necessary to provide LED on both sides of the board in order to direct light in both directions of the lamp because LED has directivity. Thus, many LED are required, which is less cost-effective.
In the meanwhile, if the battery is burn out during night time, LED stops flashing so that it cannot carry out its original function as the lamp for construction work.
Therefore the degree of visual recognition of the lamp is degraded, thus decreasing safety of drivers and the like.
SUMMARY OF THE INVENTIONAn object of the present invention is to provide a cost-effective lamp for construction work.
Another object of the present invention is to provide a lamp for construction work which gives a high degree of visual recognition.
Still another object of the present invention is to provide a lamp for construction work which uses efficiently light emitted from a light source having directivity.
Still another object of the present invention is to provide a lamp for construction work which can be recognized visually even when no light is emitted from light source.
In order to achieve these objects, a lamp for construction work in one aspect of the present invention emits light at least in two directions for warning, and includes a light source which emits light having directivity, a housing which is made of a transparent material and covers the light source, and a light flux generating means for changing a proceeding direction of the light emitted from the light source and generating at least two light flux which are directed in opposing directions.
In the thus formed lamp for construction work, at least two light flux which are directed in opposing directions are generated from the light emitted from one light source so that the overall number of light sources can be reduced, and a manufacturing cost can be reduced.
In order to achieve the above objects, a lamp for construction work in another aspect of the present invention includes a light source capable of repeatedly flashing, a housing which is made of a transparent material and covers the light source, and a reflector which is provided in part of the housing for reflecting light entered from the outside.
Since the light entered from the outside is reflected from the reflector, the thus formed lamp for construction work can show its existence to drivers and the like during night time even when the light source does not flash, thus improving the degree of visual recognition.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a front view of a lamp for construction work according to one embodiment of the present invention.
Fig. 2 is a side view when seen from line II-II ofFig. 1.
Fig. 3 shows a structure of a cross section viewed from line III-III of Fig. 1.
Fig. 4 shows a structure of a cross section viewed from line IV-IV of Fig. 2.
Fig. 5 is an enlarged view showing a structure of "X" portion of Fig. 3.
Fig. 6 is an overall perspective view of a conventional lamp for construction work.
Fig. 7 shows a structure of a cross section viewed from line VII-VII of Fig. 6.
Fig. 8 shows a structure of a cross section viewed from line VIII-VIII of Fig. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTSFig. 1 is a front view of a lamp for construction work according to one embodiment of the present invention, and Fig. 2 is a side view thereof when seen from line II II of Fig. 1.
With reference to these drawings, a lamp for construction work 1 is provided such that circular lidlike housings 3a and 3b made of a red transparent plastic material are connected together, and reflectors 5a and 5b are attached to the center portion of each housing for reflecting light entered from the outside.
Cylindrical supports 7a and 7b are connected to the bottom of housings 3a and 3b and a cylindrical cap 9 having a band 11 for attaching to the pole f--r construction work is provided under the supports.
Fig. 3 is a cross section viewed from line III-III ofFig. 1, and Fig. 4 is a cross section viewed from line IVIV of Fig. 4.
With reference to these drawings, in the center of disk-like housings 3a and 3b is provided a disk-like printed board 15. LED 13a-13f are provided radially about printed board 15, and each terminal 17a-17f is secured to printed board 15. As can be seen in the figure, an electric power is supplied to board 15 through cords 21, and terminals 17a and 17f are connected with each other by a printed board (not shown) formed on board 15. Thus, light emitted from each of LED 13a-13f is directed in a radial direction about printed board due to its directivity. Also, a ring-like space having a triangularshaped cross section which is formed by reflection surfaces 19a and 19b and a cylindrical circumferential wall 25 is provided on the entire outer periphery of housings 3a and 3b.
Fig. 5 shows "X" portion of Fig. 3 in an enlarged manner, wherein hatching showing cross sectional regions is omitted for clear understanding.
Referring to this figure, traveling directions of light flux 22 emitted from LED 13b will be described below.
Light 22 having directivity which is emitted from LED 13b enters housing 3a and 3b made of transparent material and reaches reflection surfaces 19a and 19b respectively.
Since reflection surfaces 19a and 19b are formed at an inclination angle of 450 with respect to the x-axis, the entered light flux are reflected therefrom to make light flux 23a and 23b and proceed outwardly to the left and to the right with respect to the x-axis. Thus, the light flux emitted from LED 13b is recognized from both sides of housings 3a and 3b. In the meanwhile, the light flux emitted from LED 13b in a direction parallel to the x-axis is not reflected from reflection surface 19a and 19b but proceeds outwardly through peripheral wall 25 as a light flux 23c. Consequently, in the lamp for construction work according to one embodiment of the present invention, the light flux emitted from LED can be recognized visually from all directions.
Although LED has been used as the light source in the above embodiment, any light source having a light directivity can be used instead of LED to provide a similar effect.
Also, reflectors are provided in the center portion of the lamp in the above embodiment, however, the light flux emitted form LED can be dispersed in the same manner in case of no reflectors.
Further, the lamp for construction in the above embodiment includes reflectors, however, only these reflectors can be attached to the lamp flr construction light shown in Fig. 6, for example, as in the conventional example to assure improvement of the degree of visual recognition of the lamp.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.