Sign box frame having cover board parallel rails, and plurality of transparent lamp holders and lamps for mounting on a wall

A sign box includes a box frame fixedly mounted on an outside wall of a building, a plurality of transparent lamp tube holders respectively mounted in the box frame and holding a respective lamp tube, a pair of parallel rails provided at one side of the box frame and defining a sliding track, a cover board inserted into the sliding track to keep the lamp tube holders from sight, and an electric box hinged to the box frame at a bottom side to hold fluorescent ballasts and starters of the lamp tubes in the lamp tube holders.

BACKGROUND OF THE INVENTION 
The present invention relates to an acrylic sign box, and more particularly 
to such an acrylic sign box that can be conveniently opened for allowing 
the maintenance engineer to inspect its internal electric arrangement. 
Sign box with lighting means may be installed in the outside wall of a 
store for display of an advertisement. A sign box for this purpose is 
generally comprised of a metal box frame, a plurality of lamp holders 
mounted inside the box frame to hold a respective lamp tube, and 
light-permeable acrylic cover boards covered on the peripheral sides of 
the box frame. Each acrylic cover board has a design on it. Because the 
box frame is made of metal, it is durable in use. However, the service 
life of the lamp tubes is short. Because the average service life of the 
lamp tubes is about 8 to 12 months, the lamp tubes must be replaced 
frequently during the service life of the box frame. When replacing a lamp 
tube, the acrylic cover boards must be removed from the box frame so that 
the maintenance engineer or worker can take the damaged lamp tube away, 
and then install a new lamp tube. During a maintenance work, a lift may be 
used to lift the maintenance engineer or worker to a certain height, 
enabling the maintenance engineer or worker to take the damaged lamp tube 
away for a replacement. Alternatively, a ladder may be used so that the 
maintenance engineer or work can climb to the designed height. However, it 
is not an easy job to remove acrylic cover boards from the box frame of a 
sign box. For removing acrylic cover boards from the box frame of a big 
scale sign box, a hoist shall be used. Because the service life of lamp 
tubes is short, the sign box user shall have to check the working 
condition of the lamp tubes regularly, and replace damaged lamp tubes. 
However, frequently loading and unloading the acrylic cover boards may do 
damage to the connection structure between the box frame and the wall of 
the building. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished to provide a sign box which 
eliminates the aforesaid problems. According to one aspect of the present 
invention, the sign box comprises a box frame having two parallel rails 
arranged at an outer lateral side and defining a sliding track, and a side 
cover board inserted into the sliding track to close the outer lateral 
side of the box frame. According to another aspect of the present 
invention, transparent, cylindrical lamp tube holders are respectively 
installed in the box frame to hold a respective lamp tubes. When the side 
cover board is removed from the box frame, the lamp tubes can be 
conveniently taken out of the respective lamp tube holders for a 
replacement. According to still another aspect of the present invention, 
the fluorescent ballasts and starters of the lamp tubes are installed in 
an electric box, which is hinged to the box frame at the bottom. When the 
electric box is opened, the maintenance engineer can inspect the 
fluorescent ballasts and the starters conveniently.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, an acrylic sign box in accordance with the 
present invention is generally comprised of a box frame 1, a side board 3, 
a plurality of lamp tube holders 4, and an electric box 5. 
The box frame 1 comprises a plurality of mounting legs 11 at one side for 
mounting, two parallel rails 2 and 2' longitudinally arranged at one side 
opposite to the mounting legs 11 and defining a longitudinal sliding track 
21. The side board 3 is inserted into the longitudinal sliding track 21 
between the parallel rails 2 and 2'. The longitudinal sliding track 21 has 
an opened top side through which the side board 3 is inserted into the 
longitudinal sliding track 21, and a closed bottom side at which the side 
board 3 is stopped. The side board 3 has a plurality of air vents 31 for 
ventilation. The lamp tube holders 4 are tubular members made of 
transparent material (transparent plastics, acrylics, . . . etc.), and 
respectively mounted in the box frame 1. Each lamp tube holder 4 holds a 
lamp tube 41. The lamp tubes 41 are respectively connected to respective 
fluorescent ballasts 51 and starters 52 in the electric box 5 by 
respective electric wires. When the side board 3 is pulled out of the 
longitudinal sliding track 21, the lamp tubes 41 can be conveniently 
removed from the respective lamp tube holders 4 for a replacement. The 
electric box 5 has a barrel 54 at one end namely the fixed end, and a hook 
53 at an opposite end namely the free end. The barrel 54 is pivoted to the 
bottom side of the box frame 1 by a pivot 55. When the electric box 5 is 
turned upwards and closely attached to the bottom side of the box frame 1, 
the hook 53 is hooked on a part of the box frame 1 to secure the electric 
box 5 in the closed position. When the hook 53 is disengaged from the box 
frame 1, the electric box 5 is turned outwards and opened for a repair 
work. 
Referring to FIG. 3, the lamp tube holder 4 comprises a plurality of 
longitudinal ribs 42 defining a plurality of open spaces. Through the open 
spaces, heat can be quickly dissipated from the lamp tube 41 into the air 
outside the sign box. The base 44 at each end of the lamp tube 41 is 
covered with a respective sealing cap 43, which seals out rain water. 
Referring to FIG. 4, the lamp tube 41 is mounted in the lamp tube holder 4, 
and the side board 3 is stopped at one end of the lamp tube holder 4. When 
the side board 3 is taken way, the lamp tube 41 is pulled out of the lamp 
tube holder 4, then the sealing cap 43 at the outer end of the lamp tube 
41 is removed from the lamp tube 41, then the lamp tube 41 is taken out of 
the lamp tube holder 4, and then the sealing cap 43 at the inner end of 
the lamp tube 41 is removed from the lamp tube 41, and a new lamp tube can 
then be installed. 
Referring to FIG. 5 and FIGS. 1 and 2 again, because the fluorescent 
ballasts 51 and the starters 52 are respectively mounted in the electric 
box 5, the maintenance engineer can conveniently inspect the fluorescent 
ballasts 51 and the starters 52 at first before checking the lamp tubes 
41. When the hook 53 is disengaged from the box frame 1, the electric box 
5 is opened, for enabling the maintenance engineer to inspect the 
fluorescent ballasts 51 and the starters 52 conveniently. 
Referring to FIGS. 6A and 6B, the longitudinal sliding track 21 or 21" can 
be made inside the box frame 1. When the side board is inserted into the 
longitudinal sliding track 21 or 21', the outer side of the box frame 1 is 
closed. When the side board is removed from the longitudinal sliding track 
21 or 21', a maintenance work can easily be performed. 
Referring to FIG. 7A, the box frame 1 is made having vertically aligned 
pairs of parallel rails 24 and 25; 26 and 27, each pair of parallel rails 
24 and 25; 26 and 27 defining a respective longitudinal sliding track 22 
or 23. Side boards 32 and 33 are respectively inserted into the 
longitudinal sliding tracks 22 and 23. Because a number of side boards are 
used to close the outer side of the box frame instead of a single side 
board, the individual side boards can easily removed from the box frame 
with less effort. 
Referring to FIG. 7B, the box frame 1 is made having pairs of parallel 
rails 24' and 25'; 26' and 27' arranged at an outer side at different 
elevations, each pair of parallel rails 24' and 25'; 26' and 27' defining 
a respective transverse sliding track 22' or 23'. The side boards 32 and 
33 are respectively inserted into the transverse sliding tracks 22' and 
23'. 
As indicated above, lamp tube holders 4 are used and installed in the box 
frame 1 to hold the respective lamp tubes 41, enabling the lamp tubes 41 
to be conveniently removed from the box frame 1 for a replacement; an 
electric box 5 is hinged to the box frame 1 to hold the respective 
fluorescent ballasts 51 and starters 52 of the lamp tubes 41, enabling the 
maintenance engineer to inspect the fluorescent ballasts 51 and starters 
52 of the lamp tubes 41 conveniently.