1. Field of the Invention
The present invention relates generally to energy saving lamp holders, and relates more particularly to an energy saving lamp holder which is in electric conduction only the whole installation is done, capable of generating anti-backspin blockage, to prevent the installation from possible electric shock and the danger for the bulb to be in backspin.
2. Description of the Prior Art
A conventional lamp holder always accompanies the bulb to be installed in it. Therefore, a variety of structures of lamp holders arise for all kinds of demands which are large in diversity. A prior art energy saving lamp holder 1, shown in FIGS. 1-3, comprises a body 11, a conducting spring leaf 12, an elastic article 13 and a positioning plate 14, where the body 11 shaped like a saucer is directly fastened to the spot during installation (for instance: the ceiling). A load cylinder 111 formed in the center of the body includes a set (two pieces) of conducting spring leaves 12 which are symmetrical in position and are connected to the opposite poles of power supply respectively. The conducting spring leaves 12 each has at its back an elastic article 13 which exerts force on the leaf once it is being pressed. Near to the top of the load cylinder 111, the positioning plate 14 is being laid and fastened, where the positioning plate 14 has at its surface a pair of symmetrical positioning grooves 141. Each of the positioning grooves 141 is further made up of a big hole 1411 and a connected thin arc groove 1412. And each of the positioning grooves 141 is connected to one of the conducting spring leaves 12. During the installation of an energy saving bulb, two conducting terminals 16 of the bulb are aimed to inserting into the big holes 1411 of the positioning grooves 141, followed by a twist along the thin arc groove 1412 for a degree until moving to a lodging point 121 on the conducting spring leaves 12 (shown in FIG. 3). At this moment, the conducting terminals 16 each presses the corresponding conducting spring leaf 12 into a slight bend, which further presses the elastic article 13 at its back. The conducting terminals 16 each is seized by a protruded structure which includes the bulges near the lodging point 121, preventing the conducting terminals 16 from back spinning (turning back). Accordingly, the conducting terminals 16 will be electrically connected to the poles of the power supply through the medium of the conducting spring leaves 12, to light the energy saving bulb.
The foregoing prior art energy saving lamp holders are in serious possibility of danger during the installation of an energy saving bulb, which take place as an installer inserted the conducting terminals 16 of an energy saving bulb into the big holes 1411 of the positioning grooves 141, followed by a twist along the thin arc groove 1412 to a position ahead of the right lodging point 121. At this moment, the conducting terminals 16 already conducted electrically with the corresponding conducting spring leaves 12 and the energy saving bulb is lighted; therefore, there could be some possibilities of danger as follows:                1. Since the circuit has been conducted to light the bulb at the moment, those who are not familiar with the installation procedure may mistake the action for completion and fail to proceed with the next. The situation looks good in the beginning (turning on and turning off are normal). Since the corresponding conducting spring leaves 12 are bent and the elastic articles 13 are compressed, both are in a position with potential energy for engaging a counteraction. Moreover, vibrations arising from uses and thermal effects will push the conducting terminals 16 spinning back from the corresponding conducting spring leaves 12. Once the conducting terminals 16 spin back to the position of the big holes 1411, the energy saving bulb is easy to come off and fall down to ground. The loss could be light as just breaking the bulb that frightens people or serious as hurting people or destroying articles, which means a potential for serious danger.        2. For those who are familiar with the installation will keep on spinning the bulb. Since the whole system is electrically conducted, an installer could be hurt for any careless uses with his tools or articles to touch the positioning grooves 141 during spinning. It is dangerous since an electric shock could be happened before the installer can complete the installation of the bulb.        3. Even if the installation is well done in locating the conducting terminals 16 exactly in the lodging points 121, the conducting terminals 16 could still come off from the lodging points 121 after a long time use under various vibrations and thermal effects because the protruded structure near the lodging point 121 are tiny bulges, which the conducting terminals 16 of the energy saving bulb as times go by will gradually spin back to the position of the big holes 1411, the energy saving bulb is then easy to come off same as in item 1. This situation is also far from safety.        
Therefore, the most serious drawback during the use for the foregoing prior art energy saving lamp holders lies in the electric conduction in the circuit network happened before the installation is completed, which enables a danger of electric shock. The fact is that there is no apparatus set for the prevention of the backspin for the energy saving bulb in the structure of the energy saving lamp holders, and the mentioned drawbacks are thus formed.
Accordingly, the inventor recognized the foregoing described drawbacks and proceeded with further research and improvement, through considerable endeavor and tests, the present invention is eventually accomplished.