US2385706A - Wrapping mechanism - Google Patents

Description

Sept. 25, 1945. T. JENSEN WRAPPING MECHANISM Filed May 13, 1943 5 Sheets-Sheet 1 INVENTOR THORMOD JENSEN ATTORNEY Sept. 25, 1945. T. JENSEN WRAPPING MECHANISM Filed May 13, 1943 5 Sheets-Sheet 2 Patented Sept. 25, 1945 WRAPPING MECHANISM Thormod Jensen, Laurelton, N. Y., assignor to American Machine & Foundry Company, a corporatlon of New Jersey Application May 13, 1943, Serial No. 486,769

Claims. (Cl. 93-2) This invention relates to wrapping machines, more particularly to improvements in the construction of the back tension plate and the mechanism for operating the lap roller.

One of'the main objects of the invention is to prevent slippage of the wrapper as it is draped about the girth of the article to be wrapped. To this end, the back tension plate, which is slid- .ably supported on the lifter table to press the wrapping material against the leading face of an article delivered to the table, may be provided with a pad provided with holes communieating with a suction chamber whereby the wrapping material will be suctionally held against the pad until the desired wrapper length is severed. Thus the wrapping material will be firmly held and slippage thereof will be prevented. In an alternative construction selected to exemplify the invention, suction cups may be mounted on the back tension plate to hold the wrapping material. With either type of construction a saving of paper is possible, since there is greater certainty that the exact length of wrapper required will be severed and therefore shorter wrapper lengths may be employed because more uniform overlaps are obtained. Therefore an excessively wide overlap will not be required to provide for occasional slippage.

Another object of the invention is to" reduce the speed at which the wrapping material is drawn downwardly bythe-lap roller over the rear face of the article onflthe lifter tableand eliminate the jerlgy motion which is imparted to the lap roller by operating mechanism now employed. To this end the lap roller is moved downwardly at a speed which is approximately 50% slower without dwelling at a midway point;

as heretofore, at which the severing of the wrapping material takes place. Thus a slower continuous drag is exerted on the wrapping material which in conjunction with the improved construction of the back tension plate will further reduce lap variations and minimize compression of soft loaves.

In the accompanying drawings, which form a part of this specification and in which like characters of reference indicate the same or like parts: I 1

Fig. 1 is a sectional side elevation of a wrapping machine equipped with the preferred form of back tension plate;

Fig. 2 is a plan view of the same taken from line 22 of Fig. 1;

Fig. 3 is a side elevation on an enlarged scale illustrating the suction valve control mechanism, taken on line 3-3 of Fi 2;

Fig. 4 is a sectional view taken from line 4-4 of Fig. 2;

Fig. 5 is a detail sectional view of the suction valve;

Fig. 6 is a cross-section of the valve taken on the line 6-6 of Fig. 5;

Fig. 7 is a detail view of a modified form of the invention, illustrated in a view similar to Fig. 3.

Referring to Figs, 1-4 of the drawings, the side frames III of the wrapping machine support a cam shaft I2 which carries a gear I secured thereon by a set screw I6 (Fig. 2). This gear is driven by another gear on the motor (not shown) of the machine. A cam 22 fixed to shaft l2 by a set screw 24 (Fig. 2) engages with a cam roller 26 supported on a stud 28 fixed to an arm 30 of a cam lever 32 loosely mounted on a stationary cross shaft 34, supported in frames l0. Cam lever 32 has another arm 36 which is connected by a stud 38 to an adjustable link 40 pivoted on a stud 48 secured to a lifter table arm 50. Arm 5!] is loosely mounted on a stationary shaft 52 supported in frames Ill and secured therein by a screw 54. In Fig. 1 the arm 50 is shown in an inclined position, and when moved by the action of cam 22, it is elevated to the horizontal position indicated by broken lines.

On arm 50 is fastened a plate 58 on which is slidably mounted the base 60. Base 60 is guided between two guide strips62 and 64 fixed to arm 50 by screws 66. On guides 62 and 64 there is secured a cross piece 68 carrying an upright rod 10 on which a bracket 12 is adjustably held by set screw 14, and on bracket 12 is mounted a top tension plate 16.

The slide or base 60 carries a bracket 18 fastened thereto by screws 80. To said bracket is secured a back tension plate 82 on which is fastened a rubber suction pad 84. The latter has a plurality of holes 86, which communicate through corresponding holes in back tension plate 82 with a suction chamber 88 formed in bracket 18.

A duct 90 extends from said chamber to the base of bracket 18. A two-way suction valve 92 is provided with a nipple 94, through which it communicates through duct 90 with chamber 88 the nipple extending through a slot in plate 58 and being screwed into bracket 18. The valve cock I I2 of said suction valve is free to rock from a position at which its port I l2b is in communication with the port 92a and the bore in nipple 94 to relieve the suction in the suction chamber 88 to a position shown in Fig. at which it places the latter in communication with a source of suction through a nipple 96 thereof on which is mounted one end of a flexible air-hose 98. The other end of the latter is mounted on a tube I00 fastened to lifter table arm 50 by clamps I02. The purpose of said flexible hose is to compensate for the sliding movement which will be described later. From tube I00, another flexible hose I03 extends to a stationary tube I04 leading to a source of suction I06, which may consist ofa vacuum tank T and a vacuum pump V driven by a motor lVI arranged as shown in Fig. l.

The angular movement of valve cock II2 from one position to the other, previously mentioned, is effected by means of a block provided with two fingers or cam lugs I08 and H0 and secured to the stem III of valve cock II2 which projects at one end of the valve seat formed in valve 92. On the other end of the valve cock is threaded a nut I I2a which maintains the cock in the valve seat. The finger I08 which turns cock II2 to the position at which .suction is applied to chamber 88, is engaged at the last part of the downward stroke 01' arm 50, by a finger I I4, pivoted on a stationary stud H6, and having an arm I I8 which is pivotally connected by a stud I20 to a link I22 connected by a stud I24 to one end of a bell-crank I26 pivoted on a stationary stud I28. On the other end of said bell-crank is pivotally mounted a link I30 connected by a stud I32 to a feeler lever I34 fulcrumed on a stud I36 fastened in an arm I38 of a stationary bracket I40. Said feeler lever has a feeler shoe I42 positioned over a material feed'runway I44 in such a way that a bread loaf or other article being advanced on said runway by the flights of an endless conveyor (not shown), will raise said feeler "shoe" I42 up to a position which, through the above described linkage, moves finger II4 into the dotted position (shown in Fig. 3) where it may engage with cam lug I08 during the descent of the lifter table and turn valve cock II2 to the "suction on position shown in Fig. 5.

The flights of the endless conveyor pass through a slot I44a in the runway I44, and refernipples 94 and 96.

As shown in Fig. l, the feeler mechanism is normally in the inactive position and the weight of "shoe" I42 holds a lug I46 of the feeler shoe against a pin I48 secured in arm I38. The cam lug H0 is positioned to engage, when the back tension plate is moved backwardly with a cam roller I50 mounted on a'stud 'I52secured to an arm I54 which is pivoted on a stud I56 secured in an extension I58 of arm 50 (Figs. 3 and 4). A torsion spring I62 having one end fixed in the head of stud I56 and the other end held in arm I54 urges a lug I84 on said 'arm against a stop lug I68 on extension I58.

When cam lug III! is moved in the direction shown by the arrow (Fig. 3), during the displacement of the back tension plate by a package or articledelivered upon the lifter table, said camlug IIO pushes the cam roller I50 out of its way. In order to prevent the impact between them from shifting the valve cock II2, a stop I68 secured to slide 60 is provided, said stop coacting with cam lug I 08 to limit the angular movement of the valve cock. When cam lug H0 is moved in the gees-zoo opposite direction, during the forward movement of the back tension plate, it slides against and is thereby displaced upwardly by cam roller I 50, which now is backed up by lug I86.

The valve cock II2 thereby is turned from the "suction on position shown in Fig. 5 to the suction off position, thereby placing the bore of the nipple 94 in communication with the port 82a of the valve 82 and destroying the suction in the suction chamber 88.

The web of wrapping material ,W is guided from a roll of wrapping material (not shown) over a stationary plate In and passes between a pair of guid rollers I13 and I15 and hangs loosely in-front of a gap closer I12 ready for an article to be wrapped therein. An article is moved along on runway I44 by the flights of the endless conveyor (not shown) and thereby lifts shoe I42 so that the valve cock II2 will be moved to fsuction on position during the descent of the lifter table. The package is then advanced by the pusher I10, which is slidably mounted in bracket I40 and actuated by mechanism not shown, forwardly across the gap-closer I12, into the position shown in Fig. 3 where the package has just brought the wrapping material into engagement with the rubber suction pad 84 to cover the suction holes 86 thereof, whereby said wrapping material is held firmly, so that no slippage thereof will occur while the package is still further advanced on to the lifter table and comes into contact with the top tension plate 16 and while the lifter table swings upwardly to draw 011 an additional length from the roll suflicient to encompass the girth of the article.

After the back tension plate has thus been displaced to the limit of its backward movement, the

lifter table is moved up to the horizontal position shown in broken lines (Fig. 1) where it dwells while the wrapping material is drawn downwardly over the rear side of the article by a lap roller I90 operated by mechanism hereinafter described. At the same time the package is being advanced oil the lifter table by two transfer arms I14 carried by two endless chains I18 running over pairs of sprockets (not shown), one pair of sprockets being suitably driven in timed relation with the operation of the lifter table. Since the construction of these transfer arms and chains, and the mechanism for driving the same is similar to that shown in the patent to F. R. Schmitt, No. 1,851,295, further description thereof is deemed unnecessary. The lower endsof said transfer arms I14 engage with the ledges I18 of back tension plate 82 (Figs. 2 and 4) and thereby advance the package from the lifter table over a roller I and the top of the operating arm I82 on which roller I80 is supported, on to the delivery table I88. The arm I 82 is operated by suitable mechanism such as shown in said patent to F. R. Schmitt, No. 1,851,295, to cause the roller I80 to pinch the wrapping material against a roller I84 on the lifter table before the package leaves the lifter table, and thus clamp the wrapping material while the lap roller I descends to its lowermost position, the knife I88 cutting the wrapping material while the lap roller is descending. Reference may also be had to said patent for the details of the mechanism for operating knife I86. While the back tension plate is being returned to the initial position by the transfer arms I14, the cam lug II 0 moves against cam roller I50 and the suction valve .cock H2 is shifted to suction ofl" position, releasing the wrapping material from the suction pad 84. As

the lifter table now goes down, ledges I18 of-the back tension plate 82 drop out of engagement with transfer arm I14 and the latter then engage the package and forward it across arm I82 and on to the delivery table. In this manner the folding of the wrapper about the girth of the article is completed when the outer bottom flap of the wrapper is wiped under the bottom of the package by the front edge of the table I88, the rear and bottom end flaps being then folded by stationary folders. It may be noted that front flaps are folded in by tuckers (not shown) during delivery of the loaf P to the lifter table, and the top flaps are folded down by folders (not shown) during the ascent of the lifter table. The position of the back tension plate 82 when disengagement with transfer arms I14 occurs, is such that it is ready for the next package and the position 'of cam lug I08 is such that it will be engaged and valve stem II2 shifted to suction on position at the last part of the downward movement of arm 50.

If however, as previously described, there is no package present on material feed runway I 44, the

finger II4 will remain in its normal position and consequently there will be no suction on rubber suction pad 84. This latter'feature prevents the wrapping material hanging over the edge of gapcloser I12, from adhering to pad 84 and thereby being improperly positioned, if no package is present.

Fig. 7 shows a modified form of the invention wherein instead of a suction pad, the necessary suction is provided by a suction cup (or plurality of suction cups) 200. For *this purpose the cup 200 is mounted in a cone shaped opening formed in back tension plate 202 and has a shank projecting' through an opening in a supporting bracket 204 and secured in the same by two halfwashers 203 fitted into a groove in the shank of cup 200 and'fastened to bracket 204 by screws 206. cup 200, it is provided with an axial hole 208, the outer end of which forms a seat for a valve 2I0, secured by a screw 2I2 to an'arm 2I4 of a lever 2I6 pivoted on: a stud 2I8 fixed in bracket 204.

The latter is fastened by screws 80a to slide 60a which 'is similar to slide 60 of the preferred form of the invention described above. Lever 2I6 also has an arm 220, which carries a cam roller 222 pivoted on a stud 224. Valve 2I0 is urged toward a closed position by a spring 226 held at one end by a stud 228 fixed to arm 2I4 and at the other end hooked on to an angle piece 230 fastened by the lower screw 206. This valve is controlled by means of a cam lug 232 of a cam piece 234 pivoted on a stud 236 held in a bracket 238 fastened by screws 240 to slide 60a. The latter is slidably mounted on alifter table 58a. secured to an arm 50a, the mounting of table 58a on arm 50a and of slide 6011 on table 58a being similar to that shown in Figs. 1 and 2. To close the valve 2) after it In order to relieve the suction in suction has been opened, as hereinafter described, cam

lug 232 coacts during the descent of lifter table I 58a with a stop screw 242 secured to a fixed bracket 244, which displaces cam lug 232.into the position shown in full lines in Fig. '7 whereby the spring 226 closes valve 2I0.

Parts 50a, 58a, 60a, 80a, I I0a etc., are similar to parts 50, 58, 60, 80, I I0 etc., of the preferred form of the invention, wherefore further description of their construction is deemed unnecessary. However it may be noted that the cam roller I50a is mounted on a stud I52a on arm I,54a fastened on a stud I 56a supported in an extension I58a of arm 50a. A torsion spring I62a, which has one end fixed in the head of stud I56a and its other end secured in arm I54a, maintains the lug I84a on arm I54a against a stop lug I66a on extension I 58a. When cam lug I'I0a passes over cam roller I50a while .the slide 60a is moving in the direction shown by the arrow, the angular position of cam 234 remains the same. When it returns to initial position, cam lug IIIla engages with cam roller I500, and cam 234 is thereby moved to the position shown in broken lines (Fig. 7), thereby opening valve 2I0 and releasing the partial vacuum formed in the space between the suction cup 200 and the wrapping material W, so that slippage of the latter as it is wrapped around an article P is prevented.

It should be pointed out, however, that when the package or article P is being delivered to the .lifter table 58a and thereby displaces the back tension plate 202 in the direction of the arrow and presses the wrapper W against the suction cup 200 a partial vacuum is formed in the latter which prevents displacement of the wrapper W while it is folded about the girth of article P by mechanism similar to that shown in Figs. 1 and 2. The partial vacuum is maintainedin suction cup 200 while lifter table is swung upwardly to a horizontal position from the inclined position represented in Fig. 7, and until the cam lug 232 engages the roller 222 while in-the dotted position shown, the lifter table then being at its horizontal position. Then while the lifter table swings downwardly to the position shown in Fig. 7, the stop screw 242 returns the cam lug 232 to the position shown in full lines and thereby permits spring 226 to close valve 232. It should be noted that to prevent excessive displacement of cam lug 232 by the impact on stop screw 242 a stop I68a is provided on slide 60a.

The lap roller I is supported in the free ends of arms I 9| carried by bell cranks I92 loosely mounted on the shaft 52. Links I93 connect the bell cranks I92 to arms I94 fastened on shaft 34. An extension on one of the arms I94 is connected by a link I95 to a cam lever I96 fulcrumed on a stud I91 supported in the side frame I0. Cam lever I96 is provided with a cam roller engaging a cam track I98 in a cam I99 fastened on shaft I 2. The shape of the cam track is such that the loop roller I90 will be lowered slowly without dwelling, as in prior machines, at a point midway of its descent while the wrapping material is being cut. With the present cam the speed with which the paper is pulled down by the lap roller is reduced approximately 50% during this part of the cycle and instead of a jerky motion there will be a continuous drag which, in con-- junction with the improved construction of the back tension plate, will greatly reduce lap variations and compression of soft loaves.

What is claimed is:

1. In a wrapping machine, the combination with a support adapted to receive an article, of mechanism for delivering an article to said support and folding a wrapper about the girth thereof while it is positioned upon said support, and a device for holding a portion of the wrapper while it is being folded about the girth of said article, a movable feeler arranged to be engaged and displaced by an article advanced by said mechanism, and instrumentalities controlled by said feeler for operating said device when said feeler is displaced by an article being delivered to said support.

2. In a wrapping machine, the combination with a support adaptedto receive an article, of mechanism for delivering an article to said support. and folding a wrapper about the girth thereof while it is positioned upon said support, and a device for suctionally holding a portion of the wrapper while it is being folded about the girth of said article, said device. including a suction cup arranged to engage a portion of the wrapper being folded by said mechanism about the girth of the article and thereby create suctional adhesion of said 'wrapper portion to said cup, and instrumentalities for relieving the suction created in said cup to release said wrapper portion.

3. In a wrapping machine, the combination with a vertically movable lifter table adapted to support an article to be wrapped and transport it from one level to another level, of a back tension plate mounted on said table in position to engage and be displaced rearwardly on said table by an article delivered to said table, a device supported on said plate in position to engage and suctionally hold a wrapper, a pusher for delivering an article to said table at one level thereof, means for positioning wrapping material in front of said table at the level at which said pusher delivers the article thereto whereby said wrapping material will be displaced o ard said plate by the article delivered to said table by said pusher and be suctionally held by said device, said device including a suction cup arranged on said plate in position to engage theportion of said wrapper displaced toward said plate during the delivery of the article to said table and thereby suctionally hold said wrapper portion, and instrumentalitiesfor relieving the suction in said cup when said'tabfihas transported said article to the other of said levels.

4. In a wrapping machine, the combination with a vertically movable lifter table adapted tosupport an article to be wrapped and transport it from one level to another level, of a back tension plate mounted on said table in position to engage and be displaced rearwardly on said table by an article delivered to said table, a device supported on said plate in position to engage and suctionally hold a wrapper, a pusher for delivering an article to said table at one level thereof, means for positioning wrapping material in front of said table at the level at which said r pusher delivers the article thereto whereby said wrapping material will be displaced toward said plate by the article delivered to said table by said pusher and be suctionally held by said device, a movable feeler arranged to be engaged and displaced by an article positioned in front of said pusher, and mechanism controlled by said feeler for connecting said device to a source of suction when said feeler is displaced by an article positioned in front of said pusher.

5. In a wrapping machine, the combination with a vertically movable support adapted to transport an article from one level at which an article is delivered to said support to another level, of means for supporting wrapping material in front of the level at which said support receives an article whereby the article will be partially enfolded in the wrapping material during its delivery to said support, a back tension plate mounted on said support and adapted to be displaced rearwardly thereon by an article deliving the delivery of the article to the support and while said support moves to the other of said levels, a ieeler arranged in the path of an article being delivered to said support and adapted to be displaced by said article, and mechanism controlled by said feeler for connecting said device to a source of suction when the feeler is displaced by an article.

6. In a wrapping machine, the combination with a vertically movable support adapted to transport an article from one level at which an article is delivered to said support to another level, of means for supporting'wrapping material in front of the level at which said support receives an article whereby the article will be partially enfolded in the wrapping material during its delivery to said support, a back tension plate mounted on said support and adapted to be displaced rearwardly thereon by an article delivered to the support, a suction device arranged on said plate in position to engage and suctionally hold a portion of the wrapping material during the delivery of the article to the support and while said support movesto the other of said levels, a feeler arranged in the path of an article being delivered to said support and adapted to be displaced by said article, and mechanism controlled by said feeler for connecting said device to a source of suction when the feeler is displaced by an article, and instrumentalities for disconnecting said device from the source of suction when said support reaches the other of said levels.

7. In a wrapping machine, the combination with a support adapted to receive an article, means for draping wrapper material in front of said support, mechanism for pushing an article into said wrapper material and on to said support to enfold the article in the wrapper material, a back tension plate movably mounted on said support resisting the movement of said article on to said support and tending to hold. the wrapper material against said article while said article displaces said plate rearwardly during delivery by said mechanism to said support, and periodic means acting in timed relation to the movement of said pusher for temporarily securing said wrapper to said back tension plate to secure said wrapper against sliding movement between said back tension plate and the adjacent face of said article, a device for moving said plate forwardly on said support to advance the article enfolded in wrapping material from said support, and instrumentalities operated by the forward movement of said plate for releasing the wrapper from said plate.

8. In a wrapping machine, the combination with a movable support adapted toreceive an. -,article, devices imparting periodic movement to and enfold the article therein as a result of the movement of said support, a back tension plate resisting the movement of said article on to said support and tending to hold the wrapper material against said, article, and means operating in timed relation tothe movement of said support for temporarily securing said wrapper to said back tension plate to secure said wrapper against slippage between said back tension plate and the adjacent face of said article, said means operating in timed relation and including suction devices and instrumentalities for periodically rendering said devices inoperative.

9. In a wrapping machine, the combination with a lifter table having a to and fro motion in a generally vertical direction and adapted to support an article to be wrapped, and be moved from one level at which an article is delivered to the table to another level at which the wrapped article is removed from the table, of a pusher for advancing an article on to the table, a back tension plate slidably mounted on said table in position to engage and be displaced rearwardly by an article delivered to the table by the pusher, devices for positioning a wrapper between said support and pusher to be folded about the article delivered to the table by the pusher, suction means on the wrapper engaging face of the back tension plate for preventing slippage of the wrapper while it is being folded about the article, and a device for interrupting the suction in said means after the table has been moved to the level at which the wrapped article is removed from the table.

10. In a wrapping machine, the combination with a lifter table having a to and fro motion in a generally vertical direction and adapted to support an article to be wrapped, and be moved from one level at which an article is delivered to the table to another level at which the wrapped article is removed from the table, of a pusher for advancing an article on to the table, a back tension plate slidably mounted on said table in position to engage and be displaced rearwardly by an article delivered to the table by the pusher, devices for positioning a wrapper between said support and pusher to be folded about the article delivered to the table by the pusher, suction means on the wrapper engaging face of the back tension plate for preventing slippage of the wrapper while it is being folded about the article, and a device for thereafter interrupting the suction in said means prior to the removal of the wrapped article from the table.

THORMOD JENSEN.

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