US3466849A - Wrapping machine - Google Patents

Description

Sept. 16, 1969 SCHAEFER ET AL 3,466,849

WRAPPING MACHINE 12 Sheets-Sheet 1 Filed Nov. 16, 1965 OMLU'Hansen R0 bev'if fc Fiche)",

E. J. SCHAEFER ET AL Sept. 16, 1969 WRAPPING MACHINE Sept. 16, 1969 E. J. SCHAEFER ET AL H 3,466,849

WRAPPING MACHINE Filed Nov. 16. 1965 12 Sheets-Sheet 5 Sept. 16, 1969 A F ET AL 3,466,849

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Sept. 16, 1969 Filed Nov. 16, 1965 E. J. SCHAEFER ET AL WRAPPING MACHINE 12 Sheets-Sheet 6 Sept. 16, 1969 E, J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE 12 Sh tsShe et 7 Filed I f I Z 5 o I I 2 7 5 O 5 319 /a2 L/ Z L M 322 F 316 323 Q at Se t. 16, 1969 E. J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet a 717 Pr fi P 6, 1969 E. J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet 9 Sept. 16,1969 5, CHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed NOV. 16. 1965 12 Sheets-Sheet 10 SUCTION PUMP Sept. 16, 1969 E. J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet 11 J54 IK/353 121.0

352 JQlb 63b kfi D O United States Patent 3,466,849 WRAPPING MACHINE Edward J. Schaefer and Omar Hansen, Jr., Blutfton, and

Robert F. McVicker, Anderson, Ind., assignors to Franklin Electric Co., Inc, Bluliton, Ind., a corporation of Indiana Filed Nov. 16, 1965, Ser. No. 508,026 Int. Cl. B6511 11/00, 49/00, 7/04 US. Cl. 53210 27 Claims ABSTRACT OF THE DISCLOSURE There are presently on the market machines for automatically wrapping articles in a thin transparent film. Such a machine is described in the copending patent application of Omar Hansen, Jr., et a1. Ser. No. 363,954, filed April 30, 1964, the machine described therein being designed for use primarily as a fresh meat wrapper in a supermarket.

Cellophane has been commonly used as the protective film, and the machine described in the Hansen et a1. patent application works very well with such a film. Newer plastic materials, such as polyolefin, have become available for use as the film, which are less expensive than cellophane, and consequently more desirable. Polyolefin is however difiicult to handle because it is very thin and, more important, it usually is electrically charged. When charged, this type of film clings to other materials such as metal and, if it becomes folded upon itself, it is very difiicult to straighten. One way in which such a film has been used has been to cut the film into sections having the approximate size necessary to wrap a series of articles, and then wrapping the articles in the sections by a combination of manual and automatic operations. Such a system is of course more costly and time consuming than a fully automatic wrapping system wherein the film is taken from a supply roll of the film material and automatically wrapped around the articles and automatically cut to sections having the right dimensions for the articles being wrapped.

Accordingly, it is an object of this invention to provide an automatic wrapping machine, capable of handling thin plastic films, such as polyolefin.

Another object is to provide a machine of the above character, including a novel film feed mechanism for stripping the film from a supply roll and maintaining the film under tension during a wrapping cycle.

A further object is to provide a machine of the above character, including novel means for controlling the free end portion of the film after a section of film has been girdle wrapped around an article and severed.

A still further object is to provide a machine of the above character, including novel means for heat sealing the section of film which has been wrapped around the article.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying figures of the drawings, in which:

FIG. 1 is a side elevational view of awrapping machine embodying the invention with some parts partially broken away;

FIG. 2 is an enlarged fragmentary view of a portion of the machine;

FIG. 3 is an end elevational view of the structure shown in FIG. 2;

FIG. 4 is a further enlarged sectional view taken on the line 44 of of FIG. 3;

FIG. 5 is an enlarged fragmentary view of another portion of the machine shown in FIG. 1;

FIG. 6 is a further enlarged fragmentary view of a portion of the structure shown in FIG. 5;

FIG. 7 is a fragmentary end elevational view of a portion of the structure shown in FIG. 6;

FIG. 8 is a fragmentary sectional view of a portion of the structure shown in FIGS. 6 and 7;

FIG. 9 is an enlarged fragmentary view of another portion of the machine shown in FIG. 1;

FIG. 10 is a further enlarged fragmentary sectional view taken on the line 1010 of FIG. 9;

FIG. 11 is a further enlarged fragmentary sectional view taken on the line 11-11 of FIG. 9;

FIG. 12 is a sectional view taken on the line 1212 of FIG. 11;

FIG. 13 is an enlarged fragmentary view of another portion of the machine shown in FIG. 1;

FIG. 14 is a plan view of the structure shown in FIG. 13;

FIG. 14a is a fragmentary view of a portion of the structure shown in FIGS. 13 and 14;

FIG. 15 is a sectional view taken on the line 1515 of FIG. 16;

FIG. 16 is an enlarged fragmentary view of another portion of the machine shown in FIG. 1;

FIGS. 17 to 23 are schematic illustrations showing the operation of the machine of FIG. 1;

FIGS. 24 to 28 are schematic illustrations showing an alternative form of a portion of the machine;

FIGS. 29 to 33 are schematic illustrations generally similar to FIGS. 24 to 28 but showing another alternative form of the portion of the machine; and

FIGS. 34 to 42 are schematic illustrations generally similar to FIGS. 24 to 28, FIGS. 29 to 33, but showing still another alternative form of the portion of the machine.

In general, a wrapping machine embodying the invention is generally similar to the wrapping machines described in the above-mentioned copending patent application Serial No. 363,954, and copending patent application Serial No. 219,482, filed August 27, 1962 (now Patent 3,248,848) in the name of Carl Littlefield. A machine of this character comprises a wrapping mechanism, an input mechanism for conveying articles to be wrapped to the wrapping mechanism, and a film supply and transport mechanism for feeding film into the wrapping mechanism, the latter mechanism wrapping the article in a section of the film and sealing the section of film around the article.

The film supply and transport mechanism comprises means for supporting a supply roll of the film, means for stripping film from the supply roll, means for transporting the film to the wrapping mechanism, and means providing a reserve supply of film under tension between the film stripper and the Wrapping mechanism. As an article is being wrapped by the wrapping mechanism, film is drawn from the reserve supply, thereby gradually depleting it. When the reserve supply has been depleted to a predetermined length of film, a drive motor connected to the supply roll and to the film stripper is automatically energized to feed film from the supply roll into the reserve supply to a sufficient extent to replenish the reserve supply. The drive motor is later automatically turned off when the reserve has been replenished, and remains off until the reserve supply has again been depleted. The film in the reserve supply is maintained under tension, the means for maintaining tension also serving to switch the drive motor on and ofl.

The film supply and transport mechanism further includes means for vertically suspending a length of film adjacent the wrapping mechanism, the latter mechanism being operable to receive an article from the article input mechanism and positioning the article adjacent the length of film and above the lower or free end of the film. The article is then moved horizontally in the forward direction against the film, causing the article to slide over a portion of the film and rest on the free end of the film. The article, and the portion of the film under it, are then moved upwardly, which movement causes the film to be folded over the top of the article and downwardly on the rearward side of the article due to the combination of the upward movement of the article and a dancer roll which pulls the film tightly over the top of the article and downwardly at its rearward side. The article is then moved horizontally in the rearward direction, causing the film at the rearward side of the article to be drawn underneath the article and to overlap its free end. Movement of the article in the rearward direction is halted momentarily while the overlapped portions of the film are over a tack sealer, and after the tack sealing operation has been completed, the section of film around the article is cut off or severed from the supply. In a preferred form of the invention, the dancer roll and a blow tube are then operable to prevent the free end portion of the film from falling or folding back on itself, or from clinging to adjacent portions of the mechanism, and to cause a new length of film to be vertically suspended in preparation for a subsequent wrapping cycle or operation.

The film tends to stick to hot surfaces, and to prevent the film from sticking to the tack sealer, the portion of the sealer contacting the article is made movable with the article. After the overlapped portions of the section of film have been tack sealed and the film cut, the article is moved through an end folding mechanism which folds the ends of the film underneath the article and moves the article to a main sealer. Again, the film is prevented from sticking to the main sealer by making the portion of the main sealer contacting the article movable with the article. After the article has passed the main sealer, it arrives at an output station which may have any desired form.

In greater detail, the wrapping machine comprises a frame 50 (FIG. 1) including two laterally spaced plate members 51 and 52 which are secured together by suitable braces and are mounted on wheels 53 for movement on the floor. Mounted on the frame between the plate members 51 and 52 are an article input mechanism 54, a wrapping mechanism 56. and a film supply and transport mechanism 57.

The article input mechanism 54 is shown as being in the form of a chain conveyor and includes two pairs of laterally spaced sprockets 58 and 59 and two laterally spaced chains 61 which mesh with the sprockets 58 and 59. Attached between the two chains 61 are a series of runners or pushers 62 which push articles placed between the chains 61 from left to right, or in the rearward direction, as the chains 61 are rotated in the clockwise direction. An article to be wrapped is placed on a horizontal plate 63 between a pair of laterally spaced, longitudinally extending guides 64, and between adjacent pushers 62, and one of the pushers 62 engages the article and pushes it along the upper surface of the plate 63 in the rearward direction into the wrapping mechanism 56. A drive mechanism is connected to rotate the sprockets 58 and 59, and the chains 61 and the pusher 62 which may be of the character described in the above-mentioned patent applications or any conventional drive. For example, the sprockets 58 and 59 may be connected to laterally extending shafts 66 which are rotatably mounted on the frame 50 between the plates 51 and 52, and connected by a suitable chain and sprocket arrangement to a main drive motor (not shown in FIG. 1) also mounted between the two plate- like members 51 and 52 generally below the input mechanism 54. It is preferred that the main drive motor for the input mechanism 54 also be connected to operate the wrapping mechanism 56 so that the rate of rotation of the chains 61 and the positions of the pushers 62 will always have a predetermined relation with the rate of operation and the positions of the parts of the wrapping mechanism 56, and consequently the two rates may be adjusted simultaneously.

The wrapping mechanism 56 comprises a bottom elevator 71 and a top elevator 72 which are supported by two pairs of arms or bars 73 and 74, one bar of each pair being shown in FIGS. 1 and 5. One bar of each pair is pivotally connected to one side of each of the elevators 71 and 72, and at substantially their centers the bars 73 and 74 are also pivotally connected to the frame of the machine as by pins 76 (FIG. 1). At least one, and preferably two, vertically extending links 77 are provided, which extend downwardly from the lower bars 73 and are connected to be moved substantially vertically in a reciprocating motion by a drive mechanism, which as previously stated is preferably the same drive mechanism as that provided for the input mechanism 54. A suitable drive for the elevators 71 and 72 and the bars 73 and 74 is described in the above-mentioned patent applications, and comprises a cam which is connected to be rotated by a drive motor, and cam follower which is connected by suitable means to the link 77, the construction of the cam and the linkage being such that the link 77 is moved periodically up and down in a reciprocating motion.

Movement of the link 77 causes the two elevators 71 and 72 to swing between horizontally aligned, intermediate positions shown in dashed lines in FIG. 1, and vertically displaced positions shown in full lines in FIGS. 1 and 5. The elevators 71 and 72 have substantially flat plates 78 and 79, respectively, which form article supporting surfaces and which are always horizontal because the bars 73 and 74 form parallel arms. \Vhen the elevators 71 and 72 are at the intermediate position, the plates 78 and 79 are at substantially the same level, as shown in dashed lines in FIG. 1. When the elevators 71 and 72 are at the vertically displaced positions, the upper surface of the plate 78 is substantially at the level of the upper surface of the plate 63 of the input mechanism 54, and the upper surface of the plate 79 of the elevator 72 is substantially at the level of a plate 81 (see FIG. 1) of an end folding and sealing apparatus 316 of the wrapping mechanism 56.

The wrapping mechanism 56 further includes plunger means for moving an article being wrapped from the bottom elevator 71 to the top elevator 72 when the two elevators are at the intermediate position, and also for moving the article from the top elevator 72 to the plate 81 when the two elevators are in the vertically displaced positions. As described in the previously mentioned Hansen et al. patent application, the plunger means comprises a top plunger 82 and a bottom plunger 83. The top plunger 82 is fastened to a slider 84 which is movable longitudinally of the machine on a suitable guide means 86, while the bottom plunger is mounted on another slider 87 which is also mounted for longitudinal movement on the machine on another guide means 88. A link 89 extends between and is connected to the two sliders 84 and 87, and a suitable cam actuated mechanism, described in the above-mentioned Hansen et al. patent application, is provided for periodically moving the sliders 84 and 87, and the plungers 82 and 83 attached thereto, longitudinally of the machine in synchronism to move the articles as previously described. The mechanism for operating the plungers 82 and 83 is constructed such that the movement of the plungers is synchronized with the movement of the two elevators 71 and 72. When the two elevators are at the intermediate position, the two plungers 82 and 83 move toward the left, or forwardly, as seen in FIGS. 1 and 5, the plunger 83 moving an article from the bottom elevator 71 to the top elevator 72, and when the two elevators are in the vertically displaced positions, the two plungers 83 and 82 move toward the right, or rearwardly, the plunger 82 moving an article from the top elevator to the plate 81.

The bottom plunger is preferably in the form of a rake, having a plurality of downwardly extending teeth which sweep across the upper surface of the plate 78 of the bottom elevator 71 and engage the rearward side of an article being wrapped when the plunger 83 is moved forwardly, in order to move an article from the bottom elevator to the top elevator. The top plunger 82 may be a simple rod-like member which angles downwardly and rearwardly as shown in FIG. 1, the lower end of the plunger 82 being at substantially the lateral center of the plate 79 of the top elevator 72. The top elevator 72 is preferably provided with a floating or longitudinally movable receiver bar 91 which is mounted such that it is capable of being moved longitudinally of the machine at substantially the lateral center of the plate 79. As described in the Hansen et al. patent application, the receiver bar 91 comprises a generally rectangular block 90 (FIG. 5) which is connected to the plate 79 by a nut and bolt arrangement 95 in a manner such that the amount of sliding friction between the block 90 and plate 79 may be adjusted. An angle shaped bracket 92 is preferably secured to the rearward side of the block, one arm of the bracket extending generally vertically and the other arm of the bracket being positioned to extend under the bottom of an article being wrapped adjacent its forward edge. As will be described hereinafter, the film being Wrapped about the article is caught between the bracket 92 and the article. When the article being wrapped is pushed by the bottom plunger 83 from the bottom elevator 71 to the top elevator 72, the forward side of the article engages the bracket 92 and pushes the bracket and the block forwardly of the machine and, subsequently, when the article is pushed by the top plunger 82 rearwardly of the machine, the plunger 82 engages the block 91 and pushes it and the article toward the right, or rearwardly until the article is deposited on the plate 81.

As described in the previously referred to Hansen et al. patent application, mounted on the upper surface of the plate 79 of the top elevator 72 are a pair of laterally spaced end folders 96, which are laterally adjustable, relative to the plate 79 depending upon the width of the article being wrapped. The folders 96 are shaped to engage the film at the lateral ends of the article and fold the film at the ends of the article as the article is being pushed from the bottom elevator 71 to the top elevator 72.

Further, as the top elevator 72 is being moved upwardly during wrapping cycle, the film is stretched tightly across the upper surface of the article so that there is a tendency for the taut film to pull the article rearwardly off of the plate 79 of the top elevator. To prevent this, a rake-like bracket 97 (FIG. 5) is provided, having a plurality to generally vertically extending stop fingers 98 (FIG. 5) which are located adjacent the rearward edge of the plate 79 of the top elevator. The bracket 97 is mounted underneath the plate 79, for pivotal movement relative to the top elevator, by means of a shaft 99, and a tension spring 101 is connected to the bracket 97 at the end of the bracket which is opposite from the fingers 98, and to the top elevator 72. The spring 101 urges the fingers 98 in the counterclockwise direction as seen in FIG. 5, or upwardly. Slots are formed in the rearward edge of the plate 79 and the fingers 98 normally extend through these slots.

To retract the fingers 98 below the upper surface of the plate 79 when either an article is being moved on to the top elevator 72 or being moved ofi of the top elevator 72, a bottom actuator 102 and a top actuator 103 are provided. The bottom actuator 102 is mounted on the plate 63 of the input mechanism 54 and extends upwardly therefrom to a position where it engages the bracket 97 forwardly of the shaft 99 and thereby pivots the bracket 97 in the clockwise direction to retract the fingers 98 when the top elevator 72 is at the intermediate position. The height of the bottom actuator 102 is adjusted such that the bracket 97 will be pivoted to lower the fingers 98 below the upper level of the plate 79. When the top elevator 72 is moved toward its upper position, the bracket 97 moves out of engagement with the bottom actuator 102 and the fingers 98 move upwardly and hold the package on the plate 79. When the elevator 72 reaches the upper position, the top actuator 103 engages the bracket 97 forwardly of the shaft 99 and pivots the bracket 97 in the clockwise direction as seen in FIG. 5 and again causes the fingers 98 to be retracted below the upper level of the plate 79, thereby permitting the article to be pushed off the top elevator 72 and on to the plate 81. Of course, as soon as the top elevator 72 again moves downwardly, the bracket 97 moves out of engagement with the top actuator 103 and the fingers 98 again move upwardly above the upper surface of the plate 79.

The wrapping mechanism 56 further includes scissorlike means for severing the film after it has been wrapped around an article and tack sealed. The severing means comprises a horizontal, laterally extending stationary blade 106 (FIG. 5) which is fixed to the frame of the machine just below and forwardly of the forward edge of the plate 81. The severing means further includes a pair of movable blades 107 carried by the top elevator 72 on the underside thereof and at the rearward edge. The movable blades 107 are carried by brackets 108 and extend laterally of the machine in end-to-end relation. As described in the copending Hansen et al. application, the two blades form a V with the apex of the V being toward the left and at substantially the lateral center of the top elevator 72. From the apex, each of the blades 107 extends laterally of the machine and rearwardly, and each of the blades also slopes downwardly a slight amount from its apex. When the top elevator 72 moves to its upper position, the outer lateral ends of the blades 107 contact the underside of the stationary blade 106, and when the brackets 108 are moved rearwardly, the downward and rearward slant of each of the blades 107 causes the blades to be in point-to-point contact only with the stationary blade 106. This produces a scissors-like action which prevents tearing or pulling of the film while it is being severed. The brackets 108 are mounted for pivotal movement on the top elevator 72 by a laterally extending shaft 109 which is fastened to the top elevator 72, and a tension spring 111 connected between the forward end of the bracket 108 and the top elevator 72 urges the bracket 108 and the blades 107 upwardly, or in the counterclockwise direction as seen in FIG. 5. The shaft 109 is also mounted for longitudinal movement relative to the top elevator 72, and as described in the abovementioned copending patent applications, after the top elevator 72 has moved to its upper position, an article on the top elevator has been pushed rearwardly by the plunger 82, and the film has been tack sealed, the bracket 108 and the shaft 109 and the blades 107 are moved rearwardly to sever the section of film around the article. The mechanism for moving the rod or shaft 109, and consequently the bracket 108 and the blades 107, longitudinally of the machine comprises a suitable cam 112 and cam follower 113 mechanism (FIG. 5) which is preferably also actuated by the main drive motor in synchronism with the movements of the elevators and the plungers.

The film, indicated by the reference numeral 121 in FIG. 1, for wrapping an article, is delivered to the wrapping mechanism 56 by the film feed and transport mechanism 57 which comprises an arbor 122 (FIGS. 1 to 3) for supporting a supply roll 123 of film, the arbor 122 being connected to be driven by a motor-gear box unit 124. As described in detail in the copending Hansen et al. patent application, the arbor 122 comprises a cylindrical tube 126, the outer diameter of which is slightly less than the inner diameter of the supply roll 123 so that the roll 123 may easily be slipped over the arbor 122. The tube 126 is connected to the motor-gear box unit 124 by a drive shaft (not shown) which extends through a support tube 127, the latter tube extending through a hole formed in a mounting plate 128. The plate 128 is secured to the frame of the machine, and the motor-gear box unit 124 is secured to one side of the plate 128 while the arbor 122 is rotatably fastened to the support tube 127 and extends laterally of the machine from the other side of the plate 128. The drive shaft extends through the support tube 127 and into the tube 126 and has a driving connection therewith. A series of slots 131 are formed through the wall of the tube 126 and a plurality of radially movable fingers 132 extend through the slots 131 and are adapted to grip the inner periphery of the supply roll 123 when the roll is positioned on the tube 126 and the fingers 132 are radially extended. The fingers 132 are connected for movement radially inward or outward to a mechanism having a manually operated actuating knob 133 at the free end of the tube 126. 7

With a film of the character herein contemplated, the film tends to cling to itself on the supply roll 123. To avoid this difficulty a stripper roller 136 is provided, the stripper roller pulling the film off the supply roll 123. To this end, the stripper roller 136 is mounted on the plate 128 and connected to be driven by the motor-gear box unit 124 (FIGS. 1 to 4). With reference to FIG. 4, the stripper rollers 136 comprises a shaft 137 having one end extending through a hole 138 formed in the mounting plate 128. The diameter of this end of the shaft 137 is reduced to form a shoulder 139 and the reduced diameter end portion of the shaft 137 is externally threaded to receive a nut 141 and a washer 142. To rigidly secure the shaft 137 to the plate 128, this end of the shaft 137 is placed in the hole 138 with the shoulder 139 abutting the margin of the hole 138, at one side of the plate 128. The washer 142 is then positioned on the shaft, and the nut 141 is threaded on the end of the shaft to clamp the washer 142 against the other side of the plate 128.

Positioned coaxially over the shaft 137 is a cylindrical tube 143 which has one end secured to an inner end plate 144 adjacent the mounting plate 128, and its other end secured to an outer end plate 146, the two plates 144 and 146 having axial holes 147 formed therethrough which receive the shaft 137. Bearings 148 are preferably provided between the end plates 144 and 146 and the shaft 137.

To rotate the tube 143 relative to the shaft 137, a sprocket 149 is rotatably positioned around the shaft 137 between the end plate 144 and the mounting plate 128 and is connected to the plate 144 by a slip clutch arrangement. The clutch comprises a disc 151 secured to the outer periphery of a hub portion of the sprocket 149 and a disc 152 of friction or brake material such as rubber positioned between the disc 151 and the end plate'144. The adjacent surfaces of the disc 151 and the plate 144 are substantially flat and parallel to each other, and the friction disc 152 transmits rotative motion from the disc 151 to the end plate 144.

To prevent the disc 151 and the sprocket 149 from moving axially away from the tube 143, a thrust bearing 153 is mounted on the shaft 137 between the sprocket 149 and the mounting plate 128. One race of the thrust bearing 153 abuts the mounting plate 128 while the other race of the thrust bearing 153 abuts the sprocket 149. Thus, axial pressure tending to move the tube 143 toward the mounting plate 128, causes an axial thrust to be exerted on the end plate 144, the friction disc 152, the disc 151, the sprocket 149, the thust bearing 153 and the stationary mounting plate 128. The thrust bearing 153 thus permits the sprocket 149 and the tube 143 to rotate freely relative to the mounting plate 128 in spite of such an axially directed thrust.

It will be apparent that the amount of such an axially directed force determines the extent of the frictional coupling between the disc 151 and the end plate 144, and consequently the amount of slip between these two members when the sprocket is being driven. The axially directed thrust may be adjusted by means of a hand wheel or knob 154 threaded on the free end of the shaft 137. A compression spring 156 is positioned between the knob 154 and the outer end plate 146, and when the knob 154 is threaded on the shaft 137, the spring 156 is compressed and urges the end plate 146 and the tube 143 toward the right, and thereby increases the frictional coupling between the disc 151 and the plate 144. If it is desired to decrease the amount of frictional coupling between the disc 151 and the end plate 144, the knob 154 is turned to move it to the left, which reduces the compressive force on the spring 156.

The knob 154 may be secured to the shaft 137 at an axially adjusted position by a set screw 158 which is threaded into a radially extending hole 159 formed in the knob 154. A nylon plug 161 is perferably positioned between the set screw 158 and engages the threads of the shafts 137. Since the spring 156 is stationary relative to the shaft 137, while the plate 146 rotates relative to the shaft 137, a washer 162 is preferably positioned between the plate 146 and the spring 156.

The stripper roller 136 is driven by the motor-gear box unit 124. A chain 163 is trained around the sprocket 149 and another sprocket 164 which is secured to the rotating tube 126 of the arbor 122. Thus, when the motor-gear box unit 124 is energized, the sprocket 164 and the film supply roll mounted on the arbor 122 are rotated in the counterclockwise direction as seen in FIG. 1, and rotation of the sprocket 164 drives the chain 163 and the sprocket 149 also in the counterclockwise direction. Further, the tooth ratio of the sprockets and the diameter of the tube 143 are such that, if there were a direct drive between the disc 151 and the plate 144, the surface speed of the tube 143 would be slightly greater than the surface speed of the largest size film supply roll normally used. During the operation of the film feed and transport mechanism 57, the film supply roll 23 is slipped over the arbor 122 and secured thereto by turning the knob 133. The supply roll is mounted with its free end extending upwardly from the rearward side of the roll, and the film is threaded from the roll 23 upwardly and over the stripper roll 136 from the rearward side thereof, then forwardly of the machine under and around the forward side of a stationary laterally extending roller 166 which is secured to the frame 50, over the top of the roller 166 and rearwardly of the machine, under and around the rearward side of a tension roller 167 (FIG. 1), over the top of the roller 167, and then forwardly of the machine and over the upper surface of the plate 168. As explained in the previously mentioned Hansen et a1. application, the tension roller 167 extends laterally of the machine and is rotatably mounted at the ends of two laterally spaced tension arms or levers which are fastened to and rotate with a shaft 169. The shaft 169 is also rotatably supported by the mounting plate 128, and one end of the shaft 169 carries a cam (located on the side of the plate 128 which is not shown in FIG. 1). The cam is connected to actuate a switch for controlling the motor-gear box unit 124. The cam and switch arrangement is such that the unit 124 is turned on when the arms 170 swing in the counterclockwise direction and reach a first predetermined position, and the unit 124 is turned off when the arms 170 swing in the clockwise direction and reach a second predetermined position. A spring (not shown) urges the arms 170 in the clockwise direction thereby maintaining tension on the film and holding the film against the stripper roller 136, and the pull of the film during a wrapping cycle urges the arms in the counterclockwise direction. During the operation of the machine, the film 121 is drawn into the wrapping mechanism as each article is being wrapped and the consequent pull on the film 121 swings the tension roller 167 and the arms 170 in the counterclockwise direction as seen in FIG. 1. When the shaft 169 and the arms 170 reach the first predetermined angular position, the cam attached to the end of the shaft 169 closes the control switch for the motor-gear box unit 124. Upon energization of the unit 124, the arbor 122 is rotated in the counterclockwise direction as seen in FIGS. 1 and 3. Further, due to the chain and sprocket connection between the anbor 122 and the stripper roller 136, the stripper roller 136 is also rotated in the counterclockwise direction as seen in FIGS. 1 and 3. As previously stated, the surface speed of the stripper roller tends to be slightly greater than the surface speed of the film supply roll 123 when the roll 123 is fresh and, consequently, has a relatively larger diameter, but the film frictionally engages the surface of the stripper roller 136 and causes the surface speed of the roller 136 to be substantially the same as the film speed. The restraining effect of the film on the stripper roller 136 results in slip of the slip clutch, and the amount of slip increases as the diameter of the supply roll decreases. Further, the amount of tension on the film between the supply roll and the stripper roller may be adjusted by adjusting the tension on the spring 156, using the knob 154. Due to the tendency of the stripper roller 136 to turn faster than the supply roll, the former strips or pulls the film from the supply roll 123. To increase the frictional coupling between the stripper roller 136 and the film 121, a plurality of bands 171 (FIGS. 2 and 3) of a friction material are fastened to the outer periphery of the tube 143. Annular grooves 172 are formed in the outer periphery of the tube 143, which receive the bands 171.

From the tension roller 167, the film 121 is threaded over the top of the plate 168 (FIGS. 1, 5 and 6) underneath a one way check mechanism 176 which is mounted on the frame of the machine over the upper surface of the plate 168. The check mechanism 176 permits movement of the film 121 in the forward direction but pinches the film 121 against the plate 168 when there is a tendency for the film 121 to move rearwardly, as when the film 121 is pulled by the tension roller 167 and the tension arms 170. At the forward edge of the plate 168 is positioned a laterally extending stationary draper shaft 177, and the film 121 normally extends downwardly over the forward side of a shaft 177. When the wrapping machine is idling between packages, the film 121 normally extends downwardly around the forward side of the shaft 177, past the rearward side of a dancer roller 178, and between the adjacent edges of the two elevators 71 and 72 when in their intermediate positions. The free end portion of the film 121 is held by a suction bafile plate 179 (FIGS. 5, 6 and 9) which extends laterally of the machine and is secured to the frame as by brackets 181. The baffle plate 179 comprises a vertically extending back 182 and a horizontal shelf 183 which extends forwardly from the lower edge of the back 182. The shelf 183 has a hollow interior which forms a suction box (FIG. 5), each end of the shelf 183 being connected by a length of hose 184 (FIG. 9) to means, such as a motor driven fan, for producing a partial vacuum. The top side of the shelf 183 has sets of holes 185 formed therein, and air is drawn into the interior of the hollow shelf 183 through the holes 185. This suction draws the film 121 to the shelf 183 and holds the free end portion of the film 121 flat against the shelf 183, thereby preventing curling of the free end of the film 121 and also preventing curling of the vertical edges of the film adjacent its free end.

The dancer roller 178 also extends laterally of the machine and mounted between two pairs of vertically extending guides 191 and 192 (FIGS. 1 and 5), the pair 191 of guides being located at one side of the machine and the pair 192 of guides being located at the other side of the machine. The guides of each pair are longitudinally spaced to form a vertical slot at each side of the machine, and the ends of the dancer roller 178 extend into the slots. The dancer roller 178 is vertically movable within the slots and, during different portions of each wrapping cycle, is supported either by a pair of lifts 193, a pair of stationary stops 194, or a pair of movable stops 196.

As shown in FIG. 5, the two lifts 193 are secured to the bottom elevator 71 and extend upwardly and forwardly from the forward edge of plate 78. As shown in FIGS. 6 and 7, the lifts 193 are spaced laterally inwardly from the guides 191 and 192, and the upper ends of the lifts are adapted to engage sleeves of the dancer roller and lift the dancer roller 178 upwardly upon movement of the bottom elevator 71 to the intermediate position. Such upward movement of the dancer roller during each wrapping cycle is desirable because it is then out of the way and permits an article to be transferred from the bottom elevator 71 to the top elevator 72 while the two elevators are at the intermediate position. Resilient bumpers 197 are preferably secured to the upper end surfaces of the lifts 193 to cushion the impact of the lifts 193 with the sleeves 190 when the lifts 193 move upwardly and engage the dancer roller 178.

One of the stationary stops 194, which may comprise ring shaped members, is positioned in the slot between the pair of guides 191 and the other of the stops 194 is positioned in the slot between the other pair of guides 192. The two stops 194 are secured to the guides 191 and 192 as by bolts 198 (FIGS. 6 and 7) at locations such that the dancer roller 178, while resting on the stationary stops 194, is spaced a short distance above the shelf 183 of the suction baffle plate 179, as shown in dashed lines in FIG. 6.

With reference to FIGS. 6 and 7, the movable stops 196 are secured to the lower ends of a pair of vertically extending levers 201, each of the levers 201 being associated with and positioned on the forward side of one pair of guides 191 and 192. Each lever 201 is mounted for pivotal movement on a lateral axis by a pair of pins 202 which in turn are mounted on blocks 203 secured to the guides 191 and 192 as by bolts 204. The stops 196 extend rearwardly of the machine from the lower ends of the levers 201, through holes 206 formed through the adjacent guides 191 and 192 and into the slots between the guides.

Above the pivotal connection 202 of each of the levers 201, a compression spring 207 is positioned between the lever 202 and the forwardmost guide of each pair. Grooves 208 are preferably formed in the levers 201 and the adjacent guides and the ends of the springs 207 are seated in the grooves 208 in order to hold the springs 207 in place. The compression springs 207 tend to pivot the levers 201 in the counterclockwise direction as seen in FIG. 6, and thus to urge the stops 196 into the holes 206. Movement of the stops 196 into the holes 206 beyond a predetermined amount is prevented however by bumpers 209 (FIG. 6) fastened to the forwardmost guides 191 and 192, which extend forwardly from the guide, the bumpers 209 being adapted to abut the levers 201.

As shown in FIG. 6, the movable stops 196, when they have been pivoted fully in the counterclockwise direction, extend into the slots between the pairs of guides 191 and 192, and the rearward side 211 of each of the stops 196 extends into the associated slot and is slanted upwardly and rearwardly from its lower side.

As shown in FIGS. 6, and 11, the dancer roller 178 includes rectangular dancer roller guide blocks 222 and 223 secured to its ends. The horizontal thickness of the outer end portions 222a and 223a of the blocks is reduced and is slightly less than the width of the slots, and the portions 222a and 223a are positioned in the slots with the vertical dimension of the portions 222a and 223a greater than the horizontal thickness. Thus, the dancer roller 179 may be moved vertically between the guides 191 and 192 but the guides and the portions 222a and 223a prevent turning movement of the dancer roller 178. Further, each of the portions 222a and 223a is slanted at its upper and forward corner 212 (FIG. 6).

The lowermost position of the dancer roller 178 is determined by the location of the stationary stops 194. Assuming that the roller 178 is initially resting on the stops 194 and the elevators 71 and 72 are at their vertically displaced positions, when the bottom elevator 71 moves upwardly the lifts 193 pick up the dancer roller 178. During such upward movement, the slanted corners 212 at the ends of the dancer roller 178 engage the slanted sides 211 of the two movable stops 196 and cam the stops 196 forwardly. The levers 201 pivot in the clockwise direction as seen in FIG. 6 against the force of the compression springs 207 to permit such forward movement of the stops 196. The dancer roller 178 is moved upwardly past the stops 196 and then the latter return to their normal positions due to the action of the springs 207. The uppermost position of the dancer roller is indicated in dash-dot lines in FIG. 6, and this position exists when the two elevators 71 and 72 are at the intermediate positions. Thus, the dancer roller 178 is moved upwardly and held there while an article is being transferred from the bottom elevator 71 to the top elevator 72. Subsequently, the bottom elevator 71 moves downwardly and permits the dancer roller 178 to drop due to the force of gravity. The extent of the downward movement of the dancer roller 178 is initially limited, however, by the movable stops 196 which engage the bottom sides of the end portions 222a and 223a of the dancer roller 178 and hold it in the intermediate position shown in full lines in FIG. 7. The dancer roller 178 is held in this intermediate position while the article is being transferred from the top elevator 72 to the plate 81. The mechanism which moves the film severing blades 107 after the film has been tack sealed, also carries a pair of actuators 216 (FIG. 6) which are located to engage the upper ends of the levers 201 and pivot the levers 201 in the clockwise direction as seen in FIG. 6. Thus, after the section of film around the article has been tack sealed, the film is severed and the levers 201 are pivoted to cause the movable stops 196 to swing toward the left as seen in FIG. 6, out of engagement with the ends of the dancer roller 178. The dancer roller again drops downwardly to the stationary stops 194, pushing the end portion of the film downwardly and laying the film on the suction baffle plate 179.

The dancer roller 178, acting in conjunction with a blow tube 236, prevents the end portion of the film from falling rearwardly upon itself after an article has been girdle wrapped and the film has been severed. Just before. the film is severed, the film is draped downwardly on the forward side of the dramr shaft 177 looped under the dancer roller 17 8, and upwardly to the rearward edge of the top elevator. The portions of the looped film on the rearward and forward sides of the dancer rolled are relatively close together, and the dancer roller and the blow tube are constructed to blow air into the space between the looped portions of the film. This air raises the pressure in this space slightly and when the film is severed, the pressure acts on the two portions of the film to hold them apart.

With reference to FIGS. 9 to 12, the dancer roller 178 comprises a tube 221, preferably made of a material such as stainless steel, and the blocks 222 and 223 secured to the ends thereof. The block 222 is secured to one end of the tube 221 as by a roll pin 224 and the other block 223 is secured to the opposite end of the tube 221 as by a set screw 226. The block 222 closes the associated end of the tube 221 and the other block 223 has a radially extending hole 227 formed thereon, which receives a relatively small tube 228 (FIG. 11). The interior of the block 223 is hollowed out to receive the associated end of the tube 221, and the tube 228 is in communication with a hollow interior of the block 223 and the interior of the tube 221.

To help to prevent the film from clinging to the dancer roller, a plurality of axially spaced rollers 231, which may be made of a material such as hard plastic, are rotatably positioned on the tube 221. The rollers 231 are held in axially spaced relation as by a plurality of C-shaped members 232 which are positioned in annular grooves 230 formed in the other periphery of the tube 221. The members 232 are generally square in cross section, and the grooves 230 are square shaped to receive the members 232. A member 232 is located at each end of each of the rollers 231, the members 232 being engageable with the ends of the rollers 231 and thereby preventing axial movement of the rollers 231 relative to the tube 221, but permitting rotative movement of the rollers relative to the tube.

In the spaces between adjacent rollers 231, a plurality of radially extending holes 233 (FIGS. 11 and 12) are formed through the wall of the tube 221, extending from the interior of the tube to the outer surface thereof, a set of three holes 233 being shown in each space, and the holes 233 are located relative to the rectangular end portions 222a and 223a of the blocks 222 and 223 such that one hole of each set opens substantially downwardly, another hole of each set opens downwardly and forwardly of the machine, and the third hole of each set opens upwardly and forwardly of the machine. As will be explained hereinafter, the tube 228 is connected to a flexible air hose 277 (FIG. 6) which leads to an air pump, and, during a portion of each wrapping cycle, air is forced into the tube 221 and out through the holes 233. The air jets passing through the holes 233 are directed to blow the severed end portion of the film forwardly and downwardly and thereby prevent this portion from falling rearwardly and contacting the portion of the film extending downwardly from the draper shaft 177.

To further ensure that the film will not fall rearwardly of the machine after it has been severed, a laterally extending blow tube 236 (FIGS. 6, 7, 9 and 10) is provided to blow the film end forwardly. The blow tube 236 is located just forwardly of the stationary draper shaft 177 (FIG. 6) and is supported by a pair of brackets 237 which are secured to the frame of the machine and engage the ends of the blow tube 236. With reference to FIG. 10, the blow tube 236 is closed at one end by a plug 238 and is open at the opposite end, the open end being adjacent the tube 228 of the dancer roller 178. Two sets 239 and 241 of holes are formed along the length of the blow tube 236 at axially spaced locations, the set 239 of the holes facing substantially forwardly of the machine and the other set 241 of the holes facing substantially downwardly. Again as will be described in more detail hereinafter, a flexible air hose 278 (see FIG. 7) is fastened to the open end of the tube 236 and leads to an air blower or pump, and during a portion of each wrapping cycle, air is forced into the tube 236 and out of the holes 239 and 241, and into the space between the adjacent portions of the looped film, and thereby prevent the free, severed end portion of the film from falling rearwardly of the machine.

The apparatus for supplying air under pressure to the dancer roller 178 and the blow tube 236 at the proper portions of each cycle is shown in FIGS. 13, 14 and 14a.

The apparatus comprises a main drive shaft 251 which extends laterally of the machine and is mounted for rotation on the frame. A main drive motor 252 is connected through a belt 253 and a gear box 254 to rotate the main shaft 251. Connected to the shaft 251 are suitable cams and cam followers, such as the cam 256 and the follower 257, moving the elevators 71 and 72, the cutting blades 106 and various other mechanisms of the machine.

In addition, a cam 258 is clamped to the shaft 251 by means of bolts 259, and the cam 258 has two edge cam surfaces which are positioned to engage and actuate two air valves 261 and 262. The valves 261 and 262 are re spectively mounted on the plate 51 by means of brackets 263 and 264. The valve 261 is connected to control the supply of air to the dancer roller 178 and the valve 262 is connected to control the supply of air to the blow tube 236.

Also mounted on the frame of the machine are an electric motor 266 and an air pump 267, the motor 266 being connected by a belt 268 to drive the air pump 267. The drive shaft of the motor may also be connected to drive a device 269 which produces a partial vacuum for the suction baffle plate 179. The device 269 may be connected by suitable conduits 270 and the hose 184 (see FIG. 9) to operate the suction baffle plate 179.

Air from the pump 267 is delivered by a flexible air tube or hose 272 to a T-fitting 273 mounted on the plate 51, for example. The T-fitting 273 receives air from the tube 272 and directs it to two other air tubes 274 and 276 which are also connected to the inlets of the valves 261 and 262, respectively. The outlets of the two valves 261 and 262 are respectively connected to the two tubes or hose 277 and 278 which supply air to the dancer roller 178 and to the blow tube 236.

As shown in FIGS. 13 and 14a, the cam 258 has the two previously referred to cam surfaces 281 and 282 formed on its outer periphery. The cam surface 282 is adapted to engage an actuating button 283 for the valve 261, which is connected to control the supply of air to the dancer roller 178, and the cam surface 282 is adapted to engage an actuating button for the valve 262, which is connected to control the supply of air to the blow tube 236. The cam surface 281 is constructed to engage the button 283, and thereby open the valve 261, during approximately a 65 arc in each circle of revolution of the drive shaft 251 and the cam 258, and the other cam surface 282 is constructed to engage the button 284, and thereby open the valve 262, during approximately a 30 arc in each circle of revolution. Further, the valves 261 and 262 are positioned and the cam surfaces 281 and 282 are constructed such that the valve 262 for the blow tube is turned on first by the cam surface 282 and remains on for approximately a 30 arc of the revolution of the cam 252. Each complete revolution of the drive shaft 251, and consequently the cam 258, corresponds to one wrapping cycle of the machine. At substantially the same time that the cam surface 282 moves out of engagement with the button 284, and thereby turns off the valve 262, the cam surface 281 engages the button 283 and turns on the valve 261 for the dancer roller 178. Then, with the valve 262 for the blow tube turned 011, the valve 261 for the dancer roller remains on for approximately a 65 arc of the revolution of the cam 258. After the cam 258 has turned through the 65 arc, the cam surface 281 moves out of engagement of the button 283 and turns off the valve 261. Both valves 261 and 262 then remain off until the cam 258 has turned sufficiently far for the cam surface 282 to again move into engagement with the button 284 and turn on the valve 262 during the next wrapping cycle. As will be explained hereinafter, the operation of the valves 261 and 262 is synchronized with the wrapping mechanism such that they are turned on from approximately the time that the film is begun to be severed until the film is moved to the suction baflile plate 179.

During each wrapping cycle, the top plunger 82 moves rearwardly of the machine and pushes the article from the top elevator 72 rearwardly toward the plate 81. During such rearward movement of the article, the film 121 is folded underneath the article and portions of the film overlap. Adjacent the forward edge of the plate 81 is provided a tack sealer 291 (FIGS. 1 and 5) which tack seals the overlapped portions of the film before the film is severed. Plastic films tend to stick to hot objects, and the tack sealer 291 is constructed to eliminate this difliculty. The tack sealer 291 extends laterally of the machine at the forward edge of the plate 81, and is mounted in an angle shaped bracket 292 (FIGS. 5 to 7) which is secured to the frame of the machine as by bolts. The tack sealer 291 comprises a cylindrical heater cartridge 293 fastened to the bracket 292 by blocks 294 which are secured to the ends of the cartridge 293 and to the bracket 292. The cartridge 293 includes a suitable heating element 296, which is connected to an electrical supply by suitable conductors 297 (FIG. 7). The cartridge 293 further includes a thermostat 298 which is connected in the power supply control circuit for the heating element 296. The thermostat 298 may be a conventional type, such as a fluid filled bulb, and is preferably accurate enough to hold the temperature of the heating cartridge to a maximum variation of 10 to 15 F It is preferred that the temperature of the tack sealer 291 be adjustable within the' range of 200 to 500 F., depending upon the particular type of film being used.

The tack sealer 291 further includes a thin walled tubular metal roller 301 (FIG. 8) which has an inner diameter somewhat greater than the outer diameter of the heating cartridge 293. The roller 301 is rotatably mounted on the heater cartridge 293 between the two mounting blocks 294 which prevent substantial longitudinal movement of the roller 301 relative to the heater cartridge 293. Further, a coating 302 of non-stick material, such as Teflon, is preferably formed on the roller 301, and the roller 301 is preferably made of a high heat conducting material such as aluminum.

During the operation of the machine, energization of the heating element 296 causes the cartridge 293 to heat up to operating temperature. The portion of the roller 301 at the top side of the tack sealer becomes hotter than the other portions because the to portion is in direct contact with the cartridge 293. The remainder of the roller 301 is at a lower temperature because it is out of direct contact with the cartridge 293, as shown in FIG. 8. As an article is pushed from the top elevator 72 toward the plate 81, the rearward edge of the article engages the roller 301 and causes the roller 301 to rotate in the clockwise direction as seen in FIGS. 6 and 8 as the package moves over the top of the tack sealer. Even though the roller 301 is hot, it is not sufliciently hot to damage or seal the film because the article and the roller 301 are moving. With such movement of the article, no one portion of the film remains in contact with the roller 301 for any length of time, and the movement of the roller, because it is in contact with the heater therein only at the upper side of the roller, results in constantly changing the portions of the roller that have to be brought up to heat. Thus, so long as the article and roller are moving, insufiicient heat is imparted to the film to effect sealing. Further, the coating 302 of Teflon helps to prevent the film from sticking to the roller.

After the film has been wrapped around the article and overlapped and the overlapped portions are over the tack sealer, movement of the article is stopped momentarily. With no movement of the article, the roller 301 also stops turning and the upper portion of the roller 301, which is in direct contact with the heating cartridge 293, rapidly becomes heated to a greater extent. The pause in the movement of the package, while the overlapmd portions of the film are over the tack sealer and before the film has been severed, is long enough for the upper portion of the roller to heat up and tack seal the film. The weight of the 15 article being wrapped presses the overlapped portions of the film against the roller 301 during the tack sealing operation.

The pause in the movement of the article, during which tack sealing takes place, may be produced by constructing the cam which moves the plunger 82 such that the plunger, and thus the article, stops while the overlapped portions of the film are over the tack sealer and then moves rearwardly again to its maximum rearward position. A pause may also be produced by making the maximum rearward position of the plunger occur when the overlapped portions of the film are over the tack sealer, and timing the movement of transport arms 311, which push the articles rearwardly after they have been pushed on to the plate 81 by the plunger 82, such that the article momentarily remains stationary before the arms 311 engage and move the article. In practice, it may be desirable to have two pauses, and consequently two tack seals, one produced by the cam construction and the other produced by the timing of the plunger 82 and the arms 311.

After the film around an article has been scaled and severed, the article is pushed by the top plunger 82 onto the plate 81 which forms part of an end folding apparatus 316 (FIGS. 1, 15 and 16). As described in the previously referred to patent applications, the transport arms 311 are arranged in pairs, the arms of each pair being laterally spaced, and are attached to a pair of laterally spaced chains 312 which are trained around two pairs of sprockets 313 and 314 (FIGS. 1 and 16). The sprockets are mounted on suitable shafts for rotation on the frame of the machine, and are preferably connected by chains and sprockets to be driven by the main drive motor 252 such that the chains 312 rotate continuously during operation in the counterclockwise direction as seen in FIG. 1. The movement of the transport arms 311 is timed with the remainder of the wrapping mechanism such that one pair of the arms 311 moves to a position adjacent the forward edge of the plate 81 after each article has been pushed from the top elevator 72 to the plate 81. As previously stated, the timing is preferably such that the article is momentarily stationary while over the tack sealer after it has been moved by the plunger 82 and before it is engaged by the arms 311.

The arms 311 move the articles across the plate 8-1 of the end folding apparatus 316, which is described in detail in the above Hansen et al. patent application and is partially shown in FIGS. 15 and 16. The end folding mechanism 316 draws the film tightly in the lateral direction across the top and bottom sides of the film, and folds the ends of the film underneath the article. After the ends of the film have been folded under the article, the articles are moved by the transport arms 311 from the plate 81 onto a main heat sealer 317 (FIGS. 1, l and 16). The main sealer 317 comprises a heating element 318 having a fiat, horizontal upper surface 319, and an endless belt 321 which is trained around a drive roller 322 and an idler roller 323. The drive roller 322 is connected by a chain 324 to be driven from the main drive motor 252 of the wrapping machine, the chain 324 preferably also being connected through a sprocket 326 to rotate the sprockets 313 and 314 and the transport arms 311. The chain 324 may, for example, mesh with a sprocket 327 which in turn is connected by gears to rotate the drive roller 322 in the clockwise direction as seen in FIGS. 1 and 15. The belt 321 is driven by the roller 322 in the clockwise direction, and the belt 321 engages and sweeps across the upper surface 319 of the heater 318. To

maintain tension on the belt 321, atension member 328 is connected to the lower end of a tension bar 329 which is pivotally mounted on the frame of the machine by a pin 331. The member 328 engages the inner surface of the belt 321 and presses the lower portion of the belt downwardly, and thereby tensions the belt 321.

To ensure that the film on the underside of the article is pressed firmly against the belt 321, two pairs of rollers 332 are mounted on the frame of the machine above the main sealer 317 and adjacent the longitudinally extending sides thereof. As explained in the previously mentioned Hansen et al. patent application, the articles are moved over the main sealer underneath the rollers 332, which are mounted such that they may swing upwardly in the counterclockwise direction as seen in FIG. 15 as the longitudinally extending sides of the articles move underneath the rollers 332, and the weight of the rollers 332 presses the article firmly against the main sealer 317.

During the operation of the end folding apparatus 316 and the main sealer 317, the transport arms 311 move the articles along the plate 81 of the apparatus 316 where the ends of the film are folded underneath the article, and onto the main sealer 317. The belt 321 is rotated such that its surface speed is the same as the speed of the article. The belt 321 is preferably made of fiber glass which is impregnated with Teflon, the Teflon again preventing or reducing the chance that the belt 321 will stick to the film on the underside of the article. The portion of the belt 321, between the article and the main heater 318, becomes heated by the heater 318 and it transfers the heat to the film underneath the article and seals the film.

At the rearward end of the main heater 317 may be provided an output conveyor 326 (FIG. 1). The transport arms 311 move the article past the main sealer 317 and to the output conveyor 326, and the latter conveyor 326 may carry the articles either to a bin or to an input of a transport and labeling machine. The conveyor 326 may have either a positive drive for moving the articles from left to right as seen in FIG. 1 or it may be inclined sufficiently for the articles to move along it due to the force of gravity.

FIGS. 17 to 23 illustrate schematically the successive stages in one wrapping cycle when an article 341 is girdle wrapped in the film 121. The stage shown in FIG. 17 occurs just after the article 341 has been moved from the infeed conveyor mechanism 54 onto the bottom elevator 71. At the same time, a preceding article 342 has been moved off from the top elevator 72 and onto the plate 81 of the end folding apparatus 316. The two elevators 71 and 72 are at their vertically displaced positions, and the free end of the film 121 is on the shelf 183 of the suction baffle plate 179 and is being held thereby. The dancer roller 178 is being supported by the stationary stops and both air valves 261 and 262 are turned off.

In FIG. 18, the two elevators 71 and 72 have been moved to the intermediate positions where they are horizontally aligned. The lifts 193 attached to the bottom elevator 71 engage the underside of the dancer roller 178 during upward movement of the bottom elevator 71 and lift the dancer roller upwardly, to the position shown in FIG .18, where the bottom plunger 83 may move the article from the bottom elevator 71 to the top elevator 72, as shown in FIG. 19. As the article 241 is being transferred from one elevator to the other, it engages the film and slides over the free end of the film 121, as it slides onto the top elevator 72. The free end portion of the film 121 is drawn off of the shelf 183 of the suction baffle plate 179 as the article 341 is pushed onto the top elevator 72. As shown in FIG. 19, the dancer roller 178 is still in the raised position where it is supported by the lifts 193.

After the article 341 has been transferred to the top elevator 72, the two elevators 71 and 72 shift to their vertically displaced positions (FIG. 20), and the film is folded over the top of the article 341 and downwardly on its rearward side. From the rearward side of the article 341, the film 121 extends downwardly and underneath the dancer roller 178, and then upwardly to the stationary draper shaft 177 and over the plate 168. When the bottom elevator 71 moves downwardly, the lifts 193 permit the dancer roller 178 to drop until the blocks at the ends of the dancer roller 178 engage the movable stops 196. The

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