Patent GB-413732-A (GB)
Title: Improvements relating to wrapping machine
IPC: B65B25/16
Filed: 1933-01-21
Abstract: 413,732. Wrapping-machines. NATIONAL BREAD WRAPPING MACHINE CO., 132, Birnie Avenue, Springfield, Massachusetts, U.S.A. Jan. 21, 1933, No. 2064. Convention date, Feb. 11, 1932. [Class 94 (i).] Relates to machines for wrapping loaves of bread &c. in paraffin paper and sealing the folds by heat. The wrapper-feeding mechanism comprises gripping means which seize and draw out a web until it is severed and locate the sheet with regard to the wrapping mechanism, means responsive to the size of the article for varying the size of the sheet being arranged to vary the timing of the knife which severs the web, with relation to the commencement of the web - feeding operation. Specification 14465/13, [Class 94 (i)], is referred to. Article feed. The loaves, which may be sliced, arrive at the base of an inclined slideway 102, shown in plan in Fig. 6, and are positioned by a stop plate 109. Conveyer chains 111, 112, adjustable with relation to each other, carry pushers or holders 135, 136, offset so that their contact faces are in alignment and opposed in pairs. If the loaves are entire it is only necessary for them to be pushed at the rear face, and the opposed pairs of holders are left at their maximum distance apart, as shown in Fig. 6. If the loaves are sliced, the slideway 102 is not used and they are placed directly between the members 135, 136, as shown in Fig. 9. The chains are held in their adjusted positions by nuts 123, Fig. 5. The articles are brought opposite a horizontally acting plunger 143, which forces them, together with a wrapper into a vertically reciprocable carrier 153. Feeding wrappers. The wrapping material is fed from a roll 200 around take-up rolls 207 to a guide plate 208, Figs. 5 and 14, so that the leading edge projects from between a roller 214 and a plate 215. A series of grippers 222 are mounted on chains 216. The grippers comprise angle bars 224, 226, Fig. 18, normally held closed by tension springs 228. On approaching the point at which the leading end of the wrapper is to be seized, the jaws are opened by the action of a stationary cam 233 upon a tail 232 of the jaw 226. The position is now as shown in Fig. 18. When the roll 231 passes the end of the cam, the jaw springs into the gripping position and seizes the forward edge of the web along its entire width, spring fingers 227 assisting in the action. The wrapper is carried to the left, Fig. 14, a length corresponding to the size of the loaf to be wrapped is cut off by a rotary cutter 212 co-operating with a backing roll 213, and the rear end of the wrapper is temporarily retained by a clamp 255 when the jaws are re-opened by a cam 234. The wrapper s now hangs, as shown in Fig. 30, in front of the article a before it is fed from the conveyer 110 to the carrier 153. The length of the wrapper has been determined meanwhile by the device shown in Fig. 21. While the article a is stationary on the conveyer, a feeler plate 300, mounted on a parallel movement 301, 302, descends and rests on the top when released by a cam 304. A slide 313, Figs. 21 and 27, is drawn to the right and releases teeth 316 from an abutment 317 on a vertical slide 318, leaving the latter free to move. The slide moves upwards, under the action of a spring 320, to the extent permitted by a stop 321 associated with the plate 300, its travel being therefore determined by the height of the loaf. At a further stage in the cycle, the slide 313 moves to the left and re-engages the abutment 317. As the engaging surfaces are at an angle to the lines of movement of the slides, the extent of movement of the slide 313 is also determined by the height of the loaf. The slide moves a segment 307 meshing with an adjustable segment 306 on a gear 244. The gear 244 forms part of a planetary system arranged about the shaft 76, Fig. 12, and the effect of the angular displacement of the shaft is to vary the timing of the knife 212 and its associated parts. As the leading edge of the web is grasped at an invariable point in the general cycle, the length of the wrapper is thus varied in accordance with the height of the article to be wrapped. If no loaf is present, the plate 300 descends so far that a dog 325 strikes the tail of a pawl 326 and disconnects the paper feed for one cycle. In a modification, the cutters may be mounted on pivoted arms. Applying wrappers. To allow the wrappers to take up the position shown in Fig. 30, a bridge plate 181 is swung about its pivot 183, and then back into alignment with the table 180. The plunger 143 then forces the loaf and wrapper into the carrier 153. The fold b, Fig. 36, is formed by the table 180, and plates 173, 193 form end tucks c. The trailing end is drawn over the top of the loaf by the spring- pressed plate 179 and is released by the clamp 255 when the carrier rises from the lower position shown in Fig. 5. A stationary member 400 folds the end over the right hand side of the loaf and a pair of end folders 405 make the folds e. The folders are mounted for slight pivotal movement about shafts on carriages which also carry folders 432, Fig. 37, which swing backwards to make the folds f. The package is now as shown in Fig. 36. Folders 435 move inwards beneath the plate 180 and turn up the parts g. One of a series of pushers 500 on chains 501 carry the package to the right, Fig. 5, a roller 442 turning up the flap h. Sealing is effected by heating elements 529, and by the delivery of molten wax by rolls 525. Slatted delivery conveyers 540, 559 remove the packages from the machine. In a modified form of folding apparatus, the flaps g, Fig. 47, are turned upwards by folding slots in the walls 450<1>, the folders 435 being held in an inoperative position. In another modification, the bridging plate 180 is replaced by a plate swinging in the opposite direction and clamping the forward end of the wrapper against an abutment. General. All parts of the machine can be adjusted to allow operation with different sizes of articles, other than the dimension which regulates the length of the wrapper. For instance, the distance apart of the plates 173, Fig. 6, is adjustable by means of a right-andleft hand screw carrying brackets 170 upon which the plates are mounted. A number of such adjusting devices are linked by sprocket chains to allow simultaneous adjustment.