| 摘要 |
<p>1,215,047. Feeding webs; packaging- machines. A. SCHMERMUND. 25 June, 1969 [19 July, 1968], No. 34599/68. Headings B8C and B8R. Webs 3 and 103, e.g. of flexible wrapping material, pass from bobbins 2, 102, carried by a support 4, to respective pairs of co-operating rollers 16, 17 and 116, 117 which are coupled to a common drive shaft (23, Fig. 2 (not shown), through two electromagnetic couplings (31), one for each pair of co-operating rollers. In operation, one of the electromagnetic couplings is energized so that the web 3 is drawn from bobbin 2 by the rollers 16, 17 and is fed past cutters 14, 15 which are operated in known manner to cut predetermined lengths of material from the web; when a photo-electric detector 300, 301 senses the end of the expiring web 3 the operative coupling is de-energized and the other coupling energized so that the web 103 is drawn from bobbin 102 by rotation of the rollers 116, 117. Bobbin 2 can then be replaced, the new web being threaded down to the now stationary rollers 16, 17 which can be spaced apart by operating a handle 33 to facilitate the threading and which will again be activated when the trailing edge of the web 103 is sensed by a further photo-electric detector 400, 401. Thus it is not necessary to stop the machine, e.g. a wrapping machine, to which the web is fed when a bobbin has to be exchanged, nor is it necessary to glue the trailing edge of one web to the leading end of the next. The cutters may be of the rotating type or of the reciprocatable type as shown; if the latter the web is arranged to be intermittent so that cutting can take place whilst the web is stationary.</p> |
