Strapping machine

Abstract: A strapping machine includes an automatic strap severing and ejecting apparatus. The strap severing device (7, 9) cooperates with the tensioning (5, 6) and feed wheels (1, 2), allowing the tensioning and feed wheels to serve a dual function, one function during normal operation of feeding and tensioning the strap (16) and a second function on a strap error. Then, after the severing device (7, 9) has severed the strap the tensioning wheels (5, 6) ejects the scrap strap (16) via a path (11).

Description: In the past, severing and ejecting strap errors from a strapping machine involved complex components which were not completely integrated into the entire strapping machine by virtue of their separate functions. For example, related prior art U.S. Patent No. 5,287,802 requires a separate apparatus to automatically sever and eject strap errors. Provision of separate components with dedicated duties related specifically to severing and rejecting strap errors leads to problems of additional mechanical complexity and the related maintenance disadvantages, additional electronic control systems, and consequent higher cost. According to this invention a strapping machine comprising a strap cutting means, a strap feeding means, and a strap tensioning means, the strap cutting means being unobtrusive to strap travel during normal operation, but being operable to sever a strap in the event of a mis-feed, and upon servering the strap to direct a downstream section of the severed strap to an ejection path through which the downstream section of the severed strap is ejected, is characterised in that the strap cutting means are disposed along a normal strap travel path from a supply reel via the strap feeding means to the strap tensioning means, the strap cutting means being positioned between the strap feeding means and the strap tensioning means and in that the severed strap is ejected by only the strap tensioning means. With the arrangement in accordance with the present invention the automatic severing and ejecting of strap errors can be established using a system which is also used for the other standard functions of a strapping machine. The strap feeding means and the strap tensioning means are additionally used to eject strap errors from the strapping machine. A preferred embodiment of a strapping machine in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Figure 1 is a front view; and, Figure 2 is a top right perspective view. Referring to Figure 1, the strap severing and ejecting apparatus of the present invention provides a strap cutter element 7 located between a first and second tension wheel set 5, 6, and a first and second feed wheel set 1, 2. The strap cutter element rotates about a strap cutter axis 8 and may be disposed within a strap cutter sleeve 9. During normal operation of the strapping machine, the strap passes undisturbed along an edge of the strap cutter element 7 through normal path 17. However, in the event of a strap error downstream of the tension wheel, the strap cutter element 7 rotates in a direction which positions a strap segment between rotating cutting surface 20 of the strap cutter element 7 and a fixed cutting surface 19. Continued rotation of the strap cutter element 7 severs the strap at that point, and also directs the downstream portion of the severed strap 16, including the strap error, into an ejection path 11, while at the same time blocking the normal path 17. A pivotable strap guide 18 may be spring loaded. The same first and second tension wheels 5, 6 which are utilized during normal operation of the strapping device are now operated to withdraw the strap 16 including the strap error out of the strapping machine for disposal or recycling. A gear motor 10 may be utilized to rotate the strap cutter element 7 between the normal position and the cutting/ejection position. A linkage may be provided for use in connection with the gear motor 10 to limit the angular displacement of the rotating strap cutter element 7. After the strap error has been completely rejected from the strapping machine, the first and second feed wheels refeed the strap through the normal path 17, past the strap cutter element 7 which has been returned to its normal operation position, and up through the chute for the next strapping job. In this manner, the first and second feed wheels 1, 2, and the first and second tension wheels 5, 6 serve dual functions, one function during normal strapping conditions, and a second function during the automatic strap ejection procedure. The dual function of the feed and tension wheels allows for a simplification and reduction of the function of the feed and tension wheels allows for a simplification and reduction of the total elements necessary for the strapping machine to carry out the required functions. This leads to cost reductions, maintenance simplification, and reliability increases over prior art strapping machines.

Claims: A strapping machine comprising: a strap feeding means (1,2), a strap cutting means (7,9), and a strap tensioning means (5, 6), the strap cutting means (7,9) being unobtrusive to strap travel during normal operation, but being operable to sever a strap (16) in the event of a mis-feed, and, upon servering the strap to direct a downstream section of the severed strap to an ejection path (11) through which the downstream section of the severed strap is ejected; characterised in that the strap cutting means (7,9) are disposed along a normal strap travel path (17) being positioned between the strap feeding means (1,2) and the strap tensioning means (5,6) and in that the severed strap (16) is ejected by only the strap tensioning means (5,6). A strapping machine according to claim 1, the strap cutting means (7, 9) being a rotatable strap cutter element (7), a rotating cutting surface (19) being located along an edge of the strap cutter element (7), and further comprising a fixed cutting surface (20) separate from and adjacent to the rotating cutting surface, a strap segment to be severed being disposed between the rotating cutting surface (19) and the fixed cutting surface (20), wherein the rotation of the cutter element through a cutting cycle places the rotating cutting surface (19) against the strap segment (16) to be severed and then moves the cutting surface (19) through the strap (16) towards the opposing fixed cutting surface (20) until the strap (16) is severed and then, in this position, directs the severed strap to the ejection path (11). A strapping machine according to claim 1 or 2, the strap tensioning means being a first tension wheel (5) and a second tension wheel (6), the strap feeding means being a first feed wheel (1) and a second feed wheel (2), the strap cutter element (7, 9) being disposed between the first and second tension wheels (5, 6) and the first and second feed wheels (1, 2), the first and second tension wheels (5, 6) being rotatable to withdraw a segment of strap (16) from the strapping machine and deliver the segment of strap (16) to the ejector path (11) and ultimately out of the strapping machine, wherein the first and second tension wheels (5, 6) serve the dual function of tensioning the strap (16) during normal operation and ejection of the strap segment (16) from the strapping machine in the event of strap error. A strapping machine according to claim 3, further comprising a pivotable strap guide (18) disposed adjacent the second tension wheel (6), the pivotable strap guide (18) being pivotable away from the normal strap travel path (17) during a strap error severing and ejection cycle, wherein rotation of the pivotable strap guide (18) away from the normal strap travel path opens the ejection path (11) to the strap segment (16) to be ejected. A strapping machine according to claim 4, wherein the pivotable strap guide (18) is spring loaded. A strapping machine according to any of the preceding claims, further comprising a gear motor (10) which rotates the strap cutter element (7) through its range of rotation. A strapping machine according to any of the preceding claims, further comprising a strap cutter sleeve (9) which houses the strap cutter element (7), the strap cutter sleeve (9) being stationary. A strapping machine according to any of the preceding claims, wherein the strap is automatically refed into the strapping machine by strap feeding means (1, 2) after completion of the strap segment ejection cycle.

Inventors: BELL LEM, PEARSON TIM, BELL, LEM, PEARSON, TIM
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1996
Main classification: B65B13
IPC codes: B65B13, B65H26, B65H23