1. Field of Invention
The present invention relates to a foldable table, and more particularly to a runner arrangement of an injection mold foldable table, wherein the runner arrangement comprises an injection attachment integrated with the injection mold tabletop to enhance the strength of the injection mold tabletop.
2. Description of Related Arts
Foldable tables, such as banquet tables, have become very popular since the tables are economy, cheap and foldable that can be quickly and easily folded for carriage and storage and unfolded for use. Especially when some participant-intensive activities take place in multi-function rooms or designated areas, the foldable tables can be temporary set up in minutes. After the functions, the foldable tables can be quickly and neatly folded up for storage.
The conventional foldable table generally comprises a tabletop A1 and a leg frame pivotally coupled at the bottom side of the tabletop A1. In order to enhance the portability of the foldable table, the tabletop A1 is made of lightweight material such as plastic. One of the common technologies to manufacture the tabletop A1 is known as the injection molding technique. Therefore, the overall weight of the foldable table will be substantially reduced by the plastic tabletop A1. However, the strength of the plastic tabletop A1 is weak and the plastic tabletop A1 is incapable of coupling with the metal leg frame. Therefore, the conventional foldable table further comprises two runners A2 extended along two longitudinal sides of the plastic tabletop A1 to enhance the strength thereof and to couple with the leg frame. The runners A2 are the essential components of the foldable table to evenly distribute the loading force on the plastic tabletop A1 to the leg frame and to ensure the attachment between the leg frame and the plastic tabletop A1.
Accordingly, in order to hold the runners A2 extended along two longitudinal sides of the plastic tabletop A1, the plastic tabletop A1 is constructed to have an outer rim A3 and an inner rim A4 to form a double-wall structure at the longitudinal sides of the plastic tabletop A1, as shown in FIGS. 1A and 1B. The runners A2 can be held the inner rim A4 only by means of screws. In particular, the runner A2 is extended along the inner side of the inner rim A4 as shown in FIG. 1A, such that the screw is arranged to hold the runner A2 at the inner rim A4. It is worth mentioning that the outer rim A3 forms a covering rim to keep the aesthetic appearance of the foldable table and has no attaching function to the runner A2. In other words, the screw cannot attach to the outer rim A3 because the sharp end of the screw will protrude out of the outer rim A3 which is dangerous and will affect the aesthetic appearance of the foldable table. Even though the runner A2 can be received between the inner and outer rims A4, A3, as shown in FIG. 1B, the screw can only attach to the runner A2 through the inner rim A4 only. The outer rim A3 is designed to hide to the runner A2 and to keep the aesthetic appearance of the foldable table. In other words, the runner A2 cannot be secured or attached to the inner rim A4 but can only be held along the inner rim A4 by the screws.
Furthermore, it is a waste of the material to form the double-wall structure for the plastic tabletop A1 because only few portions of the inner rim A4 are used for the screws to hold the runner A2 in position. The injection process of the plastic tabletop A1 is complicated to ensure the alignment between the runner A2 and the inner rim A4. Most importantly, the holding point between the runner A2 and the inner rim A4 via the screw is relatively weak because it is limited by the thickness of the inner rim A4, wherein the holding point can only withstand 4 to 5 N (Newton force). Since the inner rim A4 at the holding point is cracked or broken, the runner A2 will not capable of reinforcing the strength of the plastic tabletop A1, such that the runner A2 will lose its original reinforcing ability to the plastic tabletop A1.
Furthermore, the double-wall structure only forms at two longitudinal sides of the plastic tabletop A1 since the runners A2 are only extended along the longitudinal sides of the plastic tabletop A1. In other words, the transverse sides of the plastic tabletop A1 only have a single-wall structure that only the outer rim is formed at each of the transverse sides of the plastic tabletop A1. Therefore, the strength of the plastic tabletop A1 is weaken at the transverse sides of the plastic tabletop A1, especially at the corner portions of the plastic tabletop A1.