Patent GB-848211-A (GB)
Title: Improvements in package and like binding mechanism
Inventor: CHEESMAN JOHN JAMES
IPC: B65B13/22
Filed: 1957-01-21
Abstract: 848,211. Binding packages. AUTOMATIC STRAPPING MACHINES Ltd. Dec. 11, 1957 [Jan. 21, 1957 (2)], Nos. 2105/57 and 2106/57. Class 94(1). [Also in Group XXIV] The invention relates to a mechanism for tying packages with flexible binding material and of the type in which the binding material passes through a connecting device, round the package, through a gripper and then into the connecting device again, whereafter the gripper closes and the binding material is drawn back by a reversed feed to form a closed loop around the package, overlapping parts being then joined together and the resulting loop separated from the supply. According to the invention the reversed feed is effected when an idle roller 15a, Fig. 6, is caused to press the binding material against a continuously rotating roller 15 driven through an adjustable friction clutch 15b. The reverse feed is automatically concluded when the slip of the roller 15, due to increasing tension in the binding material, reaches a predetermined degree. Actuation of the next step after such conclusion, or initiation of a subsequent series of steps, may also be automatically performed. The invention is described as applied to the manually controlled mechanism disclosed in Specification 698,181 to adapt it for automatic operation. At the start of a cycle the binding material is already looped loosely around the material with its free end held in the gripper. The reverse feed of the flexible binding material is effected by the energization of a magnetic clutch 27, Fig. 3, causing a link 27d to be driven by a power source 17 against spring means 27b, to the broken line position and so rock a shaft 26a carrying idle rollers. This motion disengages an idler roller used to press the binding material against a forward feed roller and bring into use the idle roller 15a used to press the binding material against the continually rotating reverse feed roller 15. This clutch 27 is under the control of automatically actuated switches SW.1 and SW.2. Preventing re-energization of clutch 27 until end of cycle. When the loop formed by the binding material is suffiiciently tensioned, the resulting drop in speed of the shaft 15d of the reverse feed roller 15 causes a centrifugal governor 31 to give way to spring means 31c, and this in turn causes a switch arm 31e of the switch SW.1 to move from its left-hand closed position shown in Fig. 6 to its right-hand open position. When SW.1 is open, the clutch 27 is de-energised to allow the idle roller 15a to rise, the binding tape having been first secured to itself to form a sealed loop and then cut from the main supply. A latch 31f holds the switch arm 31e in this right hand open position to keep the clutch 27 de-energised until the end of the remainder of the machine cycle when the latch 31f is tripped by a cam acting on a lever 21c to permit the switch SW.1 to be closed under spring pressure; all the parts being then in the position shown in Fig. 6 ready for the next machine cycle. Preventing operation until old loop is removed. The control circuit of the clutch 27 may also include another switch SW.2 to prevent further operation until the previously connected loop has been removed from the binding plane. The switch SW.2, in series with the switch SW.1, is controlled by a lever 32c, Fig. 3, on a pivoted arm 32d. As shown SW.2 is open to prevent the initiation of a cycle by a push button. When a completed loop is removed from the machine the withdrawal of such a loop momentarily withdraws a pin 32a from under the lever 32c allowing the arm 32d to tilt clockwise and cause the lever 32c to close the switch SW.2. A fresh cycle may then be started. During such a cycle a pin 21d on the wheel 21a deflects the arm 32d back to the position shown and spring means then moves the pin 32a back under the lever 32c to hold it in this postion until the next completed loop is removed. Preventing operation if sleeve material for connecting overlapping layers of the binding material together is exhausted. The above described lever 32c and switch SW.2 may be used additionally to prevent initiation of a further operational cycle when the supply of the flexible material for forming a sleeve for joining the overlapping ends of the binding material together is about to run out. For this purpose a feeler 33, Figs. 1 and 3, is spring pressed against a strip of flexible sleeve forming material 33a and, when no strip 33a is present an arm 33c of said feeler moves into a slot 32e of the lever 32c to stop it dropping; the switch SW.2 being thus held open independently of the pin 32a. Preventing fouling of the joint or seal if a previously connected loop is still in position in the binding plane, by the forwardly projected end of a strip. For this purpose, Fig. 7, switch SW.3 which is normally closed and switch SW.4 which is normally opened are included in the starting circuit of the motor 35 by which the machine is powered. Switch SW.3 is momentarily opened by the cam means 21c just after the forward feed of the strip has started, thereby to de-energize the starter 34 and driving motor 35. The switch SW.4 is momentarily closed, on removal of a formed loop, to re-energize the starter and thereby re-start the motor 35. This momentary closing of the switch SW.4 can be performed by a pin 32f.