The present invention relates generally to a system and method of attaching and aligning reinforcing bars in a framework for supporting a concrete matrix. More particularly, this invention pertains to an apparatus and method of attaching bar clips to reinforcing bars so as to join the bars in a framework. Even more particularly, this invention pertains to a clip applicator system for applying bar clips for joining pairs of reinforcing bars in a parallel orientation.
It has been long known in the art of reinforced concrete structures to provide fastening means for aligning and attaching reinforcing bars in a framework prior to encasing such bars in a concrete matrix. One well known fastening means used in forming a framework of reinforcing bars is to wrap adjacent bars with wire ties, or other similar binding materials. Another well known fastening means is to attach such reinforcing bars by welding instead of wrapping. Both of these fastening means provide for attaching bars arranged in either transverse or parallel orientations. However, both means are labor intensive and, thus, more expensive when compared to the use of more recently developed reinforcing bar clips.
Plastic clips have been developed to provide a means of rapidly attaching adjacent reinforcing bars that are arranged in transverse orientations. For example, Padrum, in U.S. Pat. No. 4,110,951, teaches a plastic U-shaped clip formed by two opposing flanges extending from a base. Each of the flanges is split to form opposing and aligned openings within each flange. The clip is positioned and aligned above two reinforcement bars that are in a transverse orientation to each other. Pressure is applied by the user to the base of the clip. This pressure causes the first reinforcing bar to be forced between the flanges and held in an upper position. Continued application of pressure upon the base causes the second reinforcing bar to be forced between the opposing split openings in the flanges and held in a lower position independent of the first bar. Padrum does not teach an apparatus or method of applying the clip to the reinforcing bars and it is expected that the clips are applied by hand operations with the user in close proximity to the reinforcing bars.
A second example of prior art plastic clips is shown in U.S. Pat. No. 5,626,436 to Dragone. The Dragone clip is a U-shaped assembly comprising two parallel longitudinal members connecting two opposed hook assemblies. Each hook assembly comprises two connecting members, each extending from one of the longitudinal members, and a fulcrum section. A hook is formed by two opposing fingers, each attached at an opposite end of the fulcrum section and extending from the fulcrum section in a direction away from the longitudinal members. A gap is formed between each pair of opposing fingers. To install the Dragone clip, a first reinforcing bar is forced between the two opposed hook assemblies and held in an upper position against the parallel longitudinal members. The parallel longitudinal members are squeezed together by the user, causing each pair of opposing fingers to spread apart. The user slips the spread fingers of the opposing hooks over a second reinforcing bar that is positioned transverse to the first bar. The user then releases the parallel longitudinal members. As the parallel longitudinal members separate, each pair of opposing fingers close around the second bar and hold it in a lower position. The Dragone clip is sized so as to hold the second bar against the first bar. Dragone does not teach an apparatus or method of applying the clip to the reinforcing bars and it is expected that the clips are also applied by hand operations with the user in close proximity to the reinforcing bars.
One shortcoming of these two current art plastic clips is the necessity of hand manipulation of a clip and a bar during the application of a clip to a bar by the user. The user must grip the clip with the fingers and thumb of one hand while forcing the prior art clip onto the reinforcement bar. This method of application does not provide even application of force across the clip and may result in the clip slipping from the user's hand or off the reinforcement bar. Also, this method may create friction and pressure on the user's fingers, thumb and palm, which, in turn may cause bruises, blisters or calluses to form on the user's fingers, thumb or palm. This disadvantage of the current art can contribute to prolonged construction times, higher labor costs and user fatigue or injury.
What is needed, then, is a bar clip applicator system that applies a reinforcement bar clip onto a reinforcing bar without the need of manipulating the clip onto the bar directly by hand. It would be advantageous if the bar clip applicator system also provided for application of a bar clip to a reinforcement bar with uniform pressure across the bar clip. It would also be advantageous if the bar clip applicator system provided for easily recognizable coding means for matching the size of the bar clip, the bar clip applicator and the reinforcement bars.