1. Field of the Invention
This invention relates to improvements in a bundling apparatus for automatically bundling bar-like articles such as steel bars, wire rods, etc. by means of a bundling wire.
2. Description of the Prior Art
Briefly describing the construction and operation of the generally used bundling apparatus, it comprises a wire feeding mechanism for feeding a bundling wire from a supply source, a wire guide path for guiding and winding the fed wire around a material to be bundled, and a twist shaft for finally twisting together the opposite ends of the wire, and further comprises important components such as a sensing device for sensing the completion of feeding of a necessary length of wire, a cutting device for the bundling wire and a bending device for bending the opposite ends of the wire. Moreover, the steps performed by the above-described devices must be a series of associated steps progressing with time and therefore, for example, the bending device or the cutting device must be disposed so as to be driven by independent drive sources while, at the same time, a limit switch for instructing the initiation or stoppage of the drive and a relay or a cam device for interlocking the limit switch must be provided. This necessitates excess space and complicates the entire apparatus. There is, therefore, a great possibility of trouble in the apparatus. The system heretofore employed as the sensing device for sensing the completion of the feeding of the bundling wire is directed to the sensing of pressure imparted by the leading end of the wire to a stop or to sensing lateral pressure provided by the leading end of the wire contacting the stop which curvedly deforms the wire in the feeding path, and depends on a mechanical impulse caused by the wire. Such means does not always exhibit the expected mechanical impulse when the fed wire accidentally has a slight inadvertent bend for some reason or other, and cannot be called a reliable sensing device.
The present invention overcomes the disadvantages peculiar to the prior art apparatus and realizes a bundling apparatus in which independent drive sources and accessory instruments for controlling the starting and stoppage of these drive sources are simplified for the series of steps forming the bundling operation, to thereby effect a plurality of processes efficiently.
Further, the present invention provides a sensing device of higher reliability for sensing the completion of the feeding of the wire and which does not depend on a mechanical impulse.