US3591065A

US3591065A - Film feed mechanism for a wrapping machine

Info

Publication number: US3591065A
Application number: US813150A
Authority: US
Inventors: Omar Hansen Jr; Donald K Shannon
Original assignee: J B DOVE Inc
Current assignee: J B DOVE Inc
Priority date: 1969-04-03
Filing date: 1969-04-03
Publication date: 1971-07-06
Anticipated expiration: 1988-07-06
Also published as: NL7004778A; CA919576A; GB1272736A

Abstract

This disclosure deals with a film feed mechanism for an automatic wrapping machine including a wrapping mechanism for wrapping each article of a series of articles in a thin protective film. The feed mechanism draws film from a film supply and feeds it to the wrapping mechanism which is constructed to pull film thereto as needed during each wrapping cycle. In the feed mechanism, film is trained around a stripper roll, through means for tensioning the film and forming a reserve supply loop, and then to the wrapping mechanism. A continuously moving drive member extends adjacent the stripper roll, and a driven member connected to the stripper roll is adapted to be drivingly engaged by the drive member in order to turn the stripper roll. Means responsive to the length of film in the reserve supply loop is connected to move the drive member into engagement with the driven member and thus turn a stripper roll when the length of film in the supply loop is depleted, and to move the drive member out of engagement with the driven member when the length of film in the supply loop is replenished.

Description

Q l hate: States Patent 1 3,59 1,065

I72] Inventors Omar HansenJr. Primary Examiner-Allen N Knowles Yardley, Pm; Attorney-Hibben, Noyes & Bicknell Donald K. Shannon, Poneto Ind. 211 Appl. No. 813,150 [22] Filed Apr. 3, i969 l l Patented y 1971 ABSTRACT: This disclosure deals with a film feed mechanism l l Assignee Dovefor an automatic wrapping machine including a wrapping Fallslngmni mechanism for wrapping each article of a series of articles in a thin protective film. The feed mechanism draws film from a film su ply and feeds it to the wrap ing mechanism whichis [S4] g i MECHANISM FORA WRAPPING constru eted to pull film thereto s needed during each E 7 D win E S. wrapping cycle. In the feed mechanism, film is trained around m g g a stripper roll, through means for tensioning the film and [52] [1.5. Cl 226/25, forming a reserve supply loop, and then to the wrapping 226/37. 226/44 mechanism. A continuously moving drive member extends ad- [5 l 1 int. Cl B65h 23/18 jacent the stripper roll, and a driven member connected to the [50] Field Of Search .4 226/37, 25, stripper roll is adapted to be drivingly engaged by the drive 240 member in order to turn the stripper roll. Means responsive to the length of film in the reserve supply loop is connected to [56] Refemncesclled move the drive member into engagement with the driven UNITED STATES PATENTS member and thus turn a stripper roll when the length of film in 1,801,739 4 1931 Gustafson 226/37 the supply loop is de lete and to move the drive member out 955 713 4/1934 T i 226/191 of engagement with the driven member when the length of 2,200,328 5/ l 940 Cohn et al. 226/37 film in the supply loop is replenished.

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PATENTED JUL slam 3591065 SHEET 2 BF 3 FILM FEED MECHANISM FOR A WRAPPING MACHINE Wrapping machines of the character disclosed in application Ser. No. 363,954, now US. Pat. No. 3,432,987 to Hansen et al. have been provided, which include a wrapping mechanism for wrapping an article in film, and a film feed mechanism for feeding film to the wrapping mechanism as needed. The feed mechanism includes means forming a reserve supply loop of film, and the wrapping mechanism pulls film from the loop during each wrapping cycle. A drive motor is connected directly to a roll of film and turns the roll in order to feed additional film into the reserve supply loop when the quantity of film in the loop is depleted. A motor control mechanism is provided which responds to the quantity of film in the loop and intermittently turns the drive motor on and off in order to maintain the quantity of film in the loop within predetermined limits.

While the foregoing mechanism works well, it has the disadvantage that it requires a separate drive motor and electrical control for turning the film supply roll, in addition to the main drive motor for the other parts of the wrapping machine. A wrapping machine of the character disclosed in U.S. Pat. No. 3,248,848 to Littlefield has been provided, which does not include a separate drive motor for the film feed mechanism, but the Littlefield machine includes a relatively complicated and expensive clutch which is subject to wear and failure.

In accordance with the present invention, the foregoing dis advantages are avoided by providing a wrapping machine including means for supporting a supply of film, a rotatably mounted film stripper roll, movable means for holding the film under tension and for forming a reserve supply loop in the film, a wrapping mechanism for wrapping an article in film and pulling film from the loop as needed during each wrapping cycle, the film extending from said supply, about said stripper roll, about said movable means and to said wrapping mechanism, continuously moving drive means extending adjacent said stripper roll, driven means connected to said stripper roll and adapted to turn said stripper roll when engaged by said drive means, and actuator means connecting said movable means and said drive means and adapted to move said drive means into and out of engagement with said driven means upon movement of said movable means such as to maintain the length of film in said loop within predetermined limits.

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

FIG. 1 is a side elevational view of a wrapping machine including a film feed mechanism embodying the invention;

FIG. 2 is an enlarged fragmentary view of a portion of the wrapping machine, showing in greater detail the film feed mechanism;

FIG. 3 is a further enlarged fragmentary view taken on the line 3-3 of FIG. 2;

FIG. 4 is another further enlarged fragmentary view taken on the line 4-4 ofFlG. 2;

FIG. Sis a fragmentary view taken on the line 5-5 of FIG. 4;

FIG. 6 is a fragmentary sectional view taken on the line 6-6 of FIG. 2; and

FIG. 7 is an enlarged fragmentary sectional view taken on the line 7-7 of FIG. 2.

With reference to FIG. 1, the wrapping machine comprises a frame 10 which is supported by a base 11, the base 11 in turn being supported on the floor by wheels 12 which permit the wrapping machine to be readily moved on the floor when desired. The base 11 may alternatively be supported on the floor by adjustable legs 13 which take the weight off the wheels 12 when the wrapping machine is in use so that the wrapping machine can not move on the floor. The frame 10 includes a pair of laterally spaced, vertically extending

side plates

10a and 10b (FIGS. 1 and 6), and mounted between the side plates is a wrapping or folding mechanism of the general character described in the above mentioned Hansen et al. patent application. Briefly, the wrapping mechanism comprises a pair of vertically movable elevators 14a and 14b (FIG. 1), a dancer roller 15, and a draper or forward roller 15a. An article infeed conveyor 16 pushes an article forwardly onto the elevator 14b, and relative movements of the elevators 14a and 14b and the dancer roller 15, transfer in the rearward direction of the article from the elevator 14b to the elevator 14a, and transfer of the article from the elevator 14a to a plate 17a result in folding of a section of film 20 around the article. The plate 17a is part of an end folding and sealing mechanism 17, and the article is then moved forwardly through the mechanism 17 and out ofthe machine. A main drive motor 18 which is continuously energized while the machine is in operation, is mounted on the base 11 and is connected through a belt and gear speed reducer 19 to a transversely extending drive shaft 21. A plurality of cams, linkages and chains (not shown) connect the drive shaft 21 to operate the elevators and the other parts of the wrapping machine. The wrapping mechanism pulls or draws film 20 to itself as needed in each wrapping cycle, and a film feed mechanism 22 supplies the film 20 to the wrapping mechanism.

The wrapping machine further includes a vertically extending mounting plate 26 (FIGS. 1 and 6) which is located at one side of the wrapping machine adjacent the plate 10a, the plate 26 being rigidly secured to the plate 10a by a plurality of bolts 27 (FIGS. 2 and 6). A spacer 28 is positioned between the

plates

26 and 10a around each bolt 27 in order to hold the plate 26 spaced from the plate 10a. A plurality of

arbors

29, 30 and 31 are rotatably mounted on the plate 26, the

arbors

29, 30 and 31 being adapted to support

film supply rolls

29a, 30a and 31a (FIG. 1). While only one roll is used at a time, it is preferred that more than one arbor be provided so that rolls of different width film, or different kinds of film, may be provided on the machine at one time. With reference to FIG. 2, a brake is preferably provided to prevent each arbor from turning too freely, and in the present instance each brake comprises a strap or belt 33 which has one end anchored as at 34 to the plate 26 and its other end fastened to a tension spring 36, each belt 33 being looped about the associated arbor. An adjustable bracket 37 is provided to fasten the spring 36 to the plate 26, the bracket 37 being connected to the plate 26 by a bolt 38 which extends through an elongated slot 39 formed in the bracket 37. Thus, to increase the amount of drag or braking force on an arbor, the bolt 38 associated therewith is loosened and the bracket 37 is shifted toward the left as seen in FIG. 2 in order to increase the tension in the spring 36. Of course, movement of the bracket 37 in the opposite direction serves to decrease the tension in the spring 36 and therefore to decrease the amount of drag on the arbor. The brakes for the three arbors are shown only in FIG. 2 for the sake of clarity in the drawings.

With reference to FIG. 6, each arbor comprises an elongated tubular member 40 which is rotatably mounted on the plate 26 in cantilever fashion. A mounting tube 41 which is rigidly secured to the plate 26 extends into one end of the member 40, and the tube 41 forms the inner race of a ball bearing 43 rotatably connecting the tube 41 with the inner periphery of the member 40. Extending laterally inwardly from the tube 41 and rigidly secured thereto is a stub shaft 44 which supports a second ball bearing 46, the bearing 46 also being connected to the inner periphery of the member 40.

Film of the type used with the wrapping machine is supplied as an endless sheet which is rolled on a tube in conventional fashion. To releasably secure such a roll of film to the arbor 29, a shoe 47 is pivotally mounted within the interior of the member 40 such that the shoe may be moved through a slot 62 into or out of binding engagement with the tube on which the film is wound. The shoe 47 is pivotally supported at approximately the center of the member 40 by a pin 48 which connects the shoe 47 with an axially extending rod 49. A plate 51 is positioned within the opposite end of the member 40 from the tube 41 and is secured thereto as by a set screw or pin 52,

and the adjacent end of the rod 49 is secured to the plate 51. To pivot the shoe 47 about the pin 40, a second rod 53 is provided, one end of the rod 53 being rotatably supported by the plate 51 and the other end of the rod 53 being supported by a bracket 56 which is fastened to the rod 49. The rod 53 extends through the plate 51 and is fastened to a knob 54 which is located beyond the end of the member 40. The end of the rod 53 adjacent the bracket 56 is threadedly connected to a sleeve 58 which is pivotally connected to the shoe 47 by another pin 59. Thus, when the knob 54 is manually turned, the threaded sleeve 50 is moved toward or away from the bracket 56, thereby causing the shoe 47 to pivot on the pin 48. The outer edge 61 of the shoe 47 extends through the slot 62 in the wall of the member 40, and when the shoe 47 is pivoted in the clockwise direction as seen in FIG. 6 by turning the knob 54in one direction, the edge 61 swings outwardly into binding engagement with the film supply roll. To release the film supply roll, the knob 54 is turned in the opposite direction to retract the shoe 47.

As previously mentioned, the other two

arbors

30 and 31 preferably have a construction identical with that of the arbor 29.

In the film feed mechanism 22 (FIGS. 1 to 3), the film 20 from a supply roll, such as the roll 29a, is trained upwardly and looped over the top ofa freely rotatable roller 64 (FIGS. 2 and 6), then underneath and around the rearward side of a stripper roll 66, then forwardly and about a tension roller 67, then rearwardly and underneath a freely rotatable roller 60, then upwardly and about another freely rotatable roller 69, and then rearwardly to the draper .roll a and the wrapping mechanism. A film check valve 63 (FIG. 1) prevents the film from being pulled back into the film feed mechanism 22.

The roller 64 is rotatably connected between the

plates

26 and 10b. The two rollers 60 and 69 are connected, at one end. to a bar 71 (FIGS. 2 and 6) which extends vertically upwardly from the plate 26 and is secured thereto by bolts 72. The other ends of the two rollers 60 and 69 are rotatably connected to the side plate 10b of the frame 10 (FIG. 6).

The stripper roll 66 (FIG. 6) is also rotatably connected to the

plates

26 and 10b, and comprises a tubular member 79 having end plates 81 and 02 positioned within the ends thereof and secured thereto as by set screws. A shaft 76 extends through the member 79 and through holes in the plates 01 and 32, and at least one of the two end plates 01 and 02 is fastened to the shaft 76. The shaft 76 is rotatably connected to the

plates

26 and 10b by bearings 77 and 70, respectively. At spaced locations along the length of the member 79 are a series of friction bands 03 which are made of silicone sponge. Some types of film are supplied by the manufacturer thereof with a light dusting or coating or powder, and it has been found that friction materials other than silicone sponge become clogged with the powder and quickly lose their frictional properties. The bands 03 frictionally grip the film 20 and pull it from the supply roll 29a when the stripper roll 66 is turned. As is best shown in FIG. 2, the roller 64 is mounted relatively close to the portion of the film 20 between the roll 66 and the tension roller 67 so as to provide a relatively large area of contact between the film 20 and the bands 03. The roller 64 also ensures that this area of contact is the same regardless of the arbor from which the film is being drawn.

The shaft 76 of the stripper roll 66 extends through an opening formed in the plate 26 and into the space between the

plates

26 and 10a, and has a sprocket 06 connected thereto. The connection between the sprocket 06 and the shaft 76 is preferably through a one-way clutch 07, for a reason to be described hereinafter, and the sprocket 86 is adapted to be driven from the drive shaft 21 by a chain 80 (FIGS. 1 and 2).

The tension roller 67 is rotatably mounted on the upper ends of a pair of laterally spaced tension arms 91 (FIGS. 2, 4 and 6) which extend downwardly from the tension roller 67 and are secured to the opposite ends of a laterally extending support rod 92. The rod 92 also extends through an opening 95 (FIG. 7) formed in the plate 26 and is rotatably supported on the plate 26 by a bearing 93. To fasten the bearing 93 to the plate 26, the housing of the bearing 93 has an annular flange 97 (FIG. 7) formed thereon, which is positioned against the inner face of the plate 26, and a square-shaped bearing ring 98 (FIGS. 2 and 7) is positioned tightly against the flange 97 and secured to the mounting plate 26 by a plurality of bolts 99 (FIG. 2). The two arms 91 are angularly biased in the clockwise direction as seen in FIGS. 1 and 2 by a coiled torsion spring 94 (FIGS. 4, 6 and 7), the inner end of the spring 94 being attached to the rod 92 and the outer end of the spring 94 being anchored to a pin 96 (FIG. 7) which is secured to the housing of the bearing 93. The amount of force exerted by the spring 94 may be adjusted by loosening the bolts 99 and turning the housing of the bearing 93, and thus the outer end of the spring 94, relative to the plate 26 and the rod 92.

When film from a supply roll supported by either of the

arbors

30 or 31 is being used, the film extends from the supply roll, through the opening (FIG. 6) formed between the arms 91, the roller 67 and the rod 92, to the roller 64.

A clutch is provided to move the chain 08 into and out of engagement with the sprocket 06 in response to angular movement of the arms 91 and the rod 92. To this end, a track arm 101 (FIGS. 4, 5 and 7) is fastened to the end of the rod 92 which is adjacent the sprocket 06, and extends radially from the rod 92. To fasten the arm 101 to the rod 92, a laterally extending hole is formed in the rod 92 to receive the track arm 101, and a set screw 102 threaded into an axially extending hole in the rod 92 secures the arm 1011 to the rod 92. A roller 103 is rotatably fastened to the outer end of the arm 101 by a bolt 104. The roller 103 extends parallel to the rod 92 and toward the plate 26, and is located generally below the sprocket 06 and the chain 88 (FIG. 5).

The clutch further includes a chain guided assembly 106 (FIGS. 3 to 5) slidably engaging the chain 00 adjacent the sprocket 06. In the present instance, the chain is a roller chain and includes two rows of links 109, the two rows being separated by rollers (FIG. 4). The assembly 106 comprises an elongated upper track 107 which has a width slightly less than the distance between the two rows of links 109 of the chain 80 so that the track 107 is able to ride on the rollers 100. The upper track 107 is supported by a track plate 111 (FIG. 3) which is pivotally fastened to the plate 26 by a bolt 112. Washers 1113 on opposite sides of the track plate 111 permit the plate 111 to freely pivot on the bolt 112. The upper track 107 is fastened to the plate 111 by a plurality of screws 114 (FIG. 3), and a tubular spacer 116 is provided around each screw 1114 to hold the track 107 spaced from the plate 111.

On the underside of the chain 00 and also connected to the track plate 111 are a pair of spaced apart lower tracks 1117 and (FIG. 5) which are positioned on opposite sides of the sprocket 06. The lower tracks 117 and 110 are fastened to the plate 111 by screws 119, and spacers 121 (FlG. 4) hold the lower guides 117 and 110 in spaced relation from the plate 111. The tracks 117 and 110 are the same width as the track 107, and the upper edges of the two tracks 117 and 110 also extend between the rows of links 109. The

tracks

117 and 118 are spaced from the upper track 107 a distance which is only slightly greater than the diameter of the rollers 108 of the chain 00, so that the

tracks

107, 117 and 110 hold the chain 00 between them.

Thus, the

tracks

107, 117 and 118 slidably engage the chain 08, and pivotal movement of the track plate 111 on the bolt 112 causes the three

tracks

107, 117 and 110 and the portion of the chain 00 between them to move upwardly or downwardly relative to the sprocket 06. As shown in solid lines in FIG. 5, the teeth of the sprocket 06 extend upwardly between the two

tracks

117 and 1 110 and into engagement with the chain 08 when the plate 111 is pivoted downwardly, but when the plate 111 is pivoted upwardly to the dashed line position shown in FIG. 5, the chain 00 is moved out of engagement with the sprocket 86.

To move the track plate 111 upwardly or downwardly, the track plate 111 is connected to respond to angular movement of the tension arms 91 and rod 92. A track link 122 (FIGS. 4 and S) is fastened to the track plate 111 by screws 123 (FIG. 5) and extends generally downwardly therefrom to a location adjacent the upper side of the roller 103. Thus, when the roller 103 moves upwardly due to angular movement of the arms 91 in the clockwise direction as seen in FIG. 2, the roller 103 engages and moves the link 122 upwardly to the dashed line shown in FIG. 5 where the chain 88 is held out of engagement with the sprocket 86. However, subsequent angular movement of the arms 91 in the counterclockwise direction swings the roller 103 downwardly to the solid line shown in FIG. 5, and the link 122 follows the movement of the roller 103 downwardly until the chain 88 drops into engagement with the sprocket 86. The sprocket 86 then supports the chain 88 and the

guides

107, 117 and 118 as the chain drives the sprocket, and the roller 103 may move further downwardly away from link 122. Thus, even though the link 122 cannot move further downwardly, the arms 91 are able to swing further in the counterclockwise direction (FIG. 2) in order to maintain tension on the film 20.

As previously mentioned, the chain 88 is connected to be driven by the main drive motor 18. The chain 88 extends from a drive sprocket 126 (FIG. 1) on the shaft 21 and angles upwardly and toward the forward end of the machine, past the sprocket 86 and to a sprocket 127 which may or may not be used to drive another part of the wrapping machine. From the sprocket 127, the chain 88 is trained about a pair of

sprockets

128 and 129 and then returns to the drive sprocket 126. The position of at least the sprocket 129 is preferably made adjustable so that the amount of tension on the chain 88 may be adjusted. The portion of the chain 88 between the

sprocket

126 and 127 is referred to herein as the slack side 129 of the chain, and the portion of the chain between the sprocket 126 and the idler sprocket 129 is referred to herein as the tight side 130 of the chain. The slack side 129 of the chain 88 must have sufficient slack for the chain to be moved out of complete engagement with the sprocket 86, and the proper amount of slack may be attained by adjusting the position of one or both of the

sprockets

128 and 129.

Considering the operation of the wrapping machine, the film 20 from the supply roll 29a is trained through the film feed mechanism 22 to the wrapping mechanism of the machine. The film may be trained around the stripper roll 66 by turning the stripper roll 66 in the clockwise direction as seen in FIG. 2, such movement of the stripper roll 66 being permitted regardless of whether the sprocket 86 is turning because of the one-way clutch 87. The clutch 87 permits the stripper roll 66 to be turned in the clockwise direction (FIG. 2) ahead of the sprocket 86, but the sprocket 86 may not be turned clockwise ahead of the stripper roll 66. The film is looped about the tension roller 67 by swinging the arms 91 in the counterclockwise direction (FIG. 2) and threading the film about the roller 67. The spring 94 connected to the rod 92 biases the arms 91 in the clockwise direction as seen in FIG. 2, but the film is prevented from being pulled out of the wrapping mechanism to the right by the check valve 63 when the machine is not being operated, and by the wrapping mechanism during a wrapping cycle.

When the drive motor 18 is energized the wrapping mechanism automatically pulls film to itself as needed during each wrapping cycle. The portion of the film extending between the stripper roll 66, the tension roller 67, and the idler roller 68 is referred to herein as a reserve supply loop. As the film is pulled from this loop into the wrapping mechanism, the tension roller 67 and the tension arms 91 swing in the counterclockwise direction as seen in FIG. 2, thus depleting the quantity of film in the loop. Such movement swings the am 101 downwardly and permits the link 122 to move downwardly, and the chain is permitted to drop into engagement with the sprocket 86. The main drive motor 18 drives the chain 88 in the clockwise direction as seen in FIGS. 1 and 2, thereby turning the sprocket 86 and the stripper roll 66 in the clockwise direction. Such movement causes the stripper roll 66 to pull or strip additional film from the supply roll 63 which also turns due to the pull on the film, thus replenishing the length of film in the reserve supply loop. The stripper roll 66 continues to strip film from the supply until the tension arms 91 swing clockwise sufficiently far to move the link 122 up wardly and lift the chain 88 out of engagement with the sprocket 86.

When the chain 88 engages the sprocket 86, additional film is not immediately fed into the reserve supply loop because the film stretches slightly and the inertia of the supply roll must be overcome. Since the wrapping mechanism continues to draw film from the reserve supply loop, the arms 91 will be swung to a generally vertical position and the roller 103 will move downwardly away from the link 122 before additional film will be fed into the reserve supply loop. When the reserve supply loop is replenished and the chain 88 is moved out of engagement with the sprocket 86, the inertia of the turning supply roll causes a small additional amount of film to be fed into the loop. The foregoing slight overtravel of the arms 91 in each direction of movement is advantageous because it reduces the frequency of engagement between the chain 88 and the sprocket 86.

It will be apparent from the foregoing that an economical and sturdy film feed mechanism for a wrapping machine has been provided. The film feed mechanism is driven by the main drive of the wrapping machine and, consequently, a separate drive for the film feed mechanism is not required. In addition, the film feed mechanism may be inexpensively manufactured and does not include any parts which are subject to excessive wear. The film feed mechanism responds quickly to a depletion of the reserve supply loop of film and it also responds quickly when the reserve supply loop has been replenished.

Iclaim:

1. In a wrapping machine for wrapping an article in a thin protective film, the machine including means for supporting a supply of film, a wrapping mechanism which draws film to itself as needed and folds the film about the article, and drive means for powering various mechanisms of the wrapping machine, the improvement of a film feed mechanism comprising a rotatable stripper roll, movable tension means, film from the supply extending about said stripper roll and to said tension means and then to said wrapping mechanism, said movable tension means being biased against the film to hold the film under tension and to form a reserve supply loop in the film from which the wrapping mechanism draws film, and clutch means for intermittently connecting said stripper roll to said drive means, said clutch means comprising a chain member which is adapted to be connected to said drive means and to be continuously moving while the machine is in operation, a sprocket member connected to said stripper roller, and actuator means responsive to the position of said movable tension means for moving said chain and sprocket members into meshing engagement and thereby rotating said stripper roll to pull film from the supply.

2. Apparatus as in claim 1, wherein said actuator means effects engagement of said chain and sprocket members when said reserve supply loop of film is depleted to a predetermined length and effects disengagement of said chain and sprocket members when said reserve supply loop of film is replenished to a predetennined length. I

3. Apparatus as in claim 1, and further including a one-way connection between said stripper roll and said sprocket member.

4. Apparatus as in claim 1 wherein said chain has a slack side and a tight side, said slack side extending adjacent said sprocket member, said actuator means being in sliding engagement with said slack side of said chain and being operable to move said slack side out of engagement with said sprocket.

5. Apparatus as in claim 4 wherein said slack side of said chain extends across the upper side of said sprocket, and the weight of said slack side is sufficient to move said slack side into engagement with said chain.

6. In a wrapping machine for wrapping an article in a thin protective film, the machine including means for supporting a supply of film, a wrapping mechanism which draws film to itself as needed and folds the film about the article, and drive means for powering various mechanisms of the wrapping machine, the improvement ofa film feed mechanism comprising a rotatable stripper roll, movable tension means, film from the supply extending about said stripper roll and to said tension means and then to said wrapping mechanism, said movable tension means being biased against the film to hold the film under tension and to form a reserve supply loop in the film from which the wrapping mechanism draws film, and clutch means for intermittently connecting said stripper roll to said drive means, said clutch means comprising a driving member which is adapted to be connected to said drive means and to be continuously moving while the machine is in operation, a driven member connected to said stripper roller, and actuator means responsive to the position of said movable tension means for moving said driving and driven members into mutual engagement and thereby rotating said stripper roll to pull film from the supply, said driving member comprising a chain, and said driven member comprising a sprocket, said actuator means comprising guide means slidably engaging said chain adjacent said sprocket and controlling the position of said chain relative to said sprocket, and means for moving said guide means in response to movement of said tension means.

7. Apparatus as in claim 6, wherein said chain and said guide means are located generally above said sprocket, and said connecting means is adapted to lift said guide means and said chain upwardly to disengage said chain and said sprocket upon movement of said tension means in one direction, and is adapted to permit said guide means and said chain to drop downwardly to engage said chain and said sprocket upon movement of said tension means in the other direction.

8. Apparatus as in claim 7, wherein said connecting means comprises a first member which is secured to said guide means, and a second member which is connected to move with said movable tension means, said second member being adapted to move upwardly into engagement with said first member and lift said first member and said guide means upwardly, said second member being further adapted to move downwardly out of engagement with said first member.

9. Apparatus as in claim I, and further including high friction means on the outer periphery of said stripper roll for frictionally engaging the film, said high friction means being made of silicone sponge.

10. in a wrapping machine for wrapping articles in a thin protective film, the combination comprising means for supporting a supply of film, a rotatably mounted film stripper roll, movably mounted film tension means, biasing means connected to said film tension means for urging said film tension means in one direction, and a wrapping mechanism for wrapping an article in film and pulling film as needed while wrapping an article, the film extending from said supply, about said stripper roll, about said film tension means, to said wrapping mechanism, a pull on said film by said wrapping mechanism moving said tension means in the opposite direction against the force of said biasing means, a continuously moving drive chain extending adjacent said stripper roll, a sprocket connected to said stripper roll and adapted to rotate said stripper roll when engaged by said chain, and

means extending between said tension means and said chain and adapted to move said chain into and out of engagement with said sprocket upon movement of said tension means, movement of said tension means in said opposite direction in response to a pull on the film causing said chain to engage said sprocket and movement of said tension means in said one direction in response to said biasing causing said chain to disengage said sprocket.

11. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising a wrapping mechanism for wrapping articles in film and pulling film thereto as needed during each wrapping c cle, means for supporting a supply of film, and a feed mec amsm for drawing film from the supply and feeding the film to the wrapping mechanism, said feed mechanism comprising a stripper roll, movable means for maintaining tension on the film and for forming a reserve supply loop of film, continuously moving drive chain means, sprocket means connected to said stripper roll and adapted to be driven by said drive chain means when engaged thereby, and actuator means connected between said movable means and one of said drive chain and sprocket means for effecting engagement of said drive chain and sprocket means when said reserve supply loop of film has been depleted to a predetermined length and for effecting disengagement of said drive chain and sprocket means when said reserve supply loop of film has been replenished to another predetermined length.

12. Apparatusas in claim 11, and further including a plurality of friction bands fastened to the outer periphery of said stripper roll, said friction bands being made of silicone sponge.

13. Apparatus as in claim 11, wherein said movable means is pivotally mounted, and said actuator means is connected to effect engagement and disengagement of said drive chain and sprocket means upon pivotal movement of said movable means.

14. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising a wrapping mechanism for wrapping articles in film and pulling film thereto as needed during each wrapping cycle, means for supporting a supply of film, and a feed mechanism for drawing film from the supply and feeding the film to the wrapping mechanism, said feed mechanism comprising a stripper roll, movable means for maintaining tension on the film and for forming a reserve supply loop of film, continuously moving drive means, driven means connected to said stripper roll and adapted to be driven by said drive means when engaged thereby, and actuator means connected between said movable means and one of said drive and driven means for effecting engagement of said drive and driven means when said reserve supply loop of film has been depleted to a predetermined length and for effecting disengagement of said drive and driven means when said reserve supply loop of film has been replenished to another predetermined length, said drive means comprising a roller chain and said driven means comprises a sprocket adapted to be rotated by said chain, and said actuator means comprises a track slidably engaging said chain, and means connecting said movable means with said track and adapted to move said track and said chain toward and away from said sprocket in response to movement of said movable means.

Claims

2. Apparatus as in claim 1, wherein said actuator means effects engagement of said chain and sprocket members when said reserve supply loop of film is depleted to a predetermined length and effects disengagement of said chain and sprocket members when said reserve supply loop of film is replenished to a predetermined length.

6. In a wrapping machine for wrapping an article in a thin protective film, the machine including means for supporting a supply of film, a wrapping mechanism which draws film to itself as needed and folds the film about the article, and drive means for powering various mechanisms of the wrapping machine, the improvement of a film feed mechanism comprising a rotatable stripper roll, movable tension means, film from the supply extending about said stripper roll and to said tension means and then to said wrapping mechanism, said movable tension means being biased against the film to hold the film under tension and to form a reserve supply loop in the film from which the wrapping mechanism draws film, and clutch means for intermittently connecting said stripper roll to said drive means, said clutch means comPrising a driving member which is adapted to be connected to said drive means and to be continuously moving while the machine is in operation, a driven member connected to said stripper roller, and actuator means responsive to the position of said movable tension means for moving said driving and driven members into mutual engagement and thereby rotating said stripper roll to pull film from the supply, said driving member comprising a chain, and said driven member comprising a sprocket, said actuator means comprising guide means slidably engaging said chain adjacent said sprocket and controlling the position of said chain relative to said sprocket, and means for moving said guide means in response to movement of said tension means.

9. Apparatus as in claim 1, and further including high friction means on the outer periphery of said stripper roll for frictionally engaging the film, said high friction means being made of silicone sponge.

10. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising means for supporting a supply of film, a rotatably mounted film stripper roll, movably mounted film tension means, biasing means connected to said film tension means for urging said film tension means in one direction, and a wrapping mechanism for wrapping an article in film and pulling film as needed while wrapping an article, the film extending from said supply, about said stripper roll, about said film tension means, to said wrapping mechanism, a pull on said film by said wrapping mechanism moving said tension means in the opposite direction against the force of said biasing means, a continuously moving drive chain extending adjacent said stripper roll, a sprocket connected to said stripper roll and adapted to rotate said stripper roll when engaged by said chain, and means extending between said tension means and said chain and adapted to move said chain into and out of engagement with said sprocket upon movement of said tension means, movement of said tension means in said opposite direction in response to a pull on the film causing said chain to engage said sprocket and movement of said tension means in said one direction in response to said biasing causing said chain to disengage said sprocket.

11. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising a wrapping mechanism for wrapping articles in film and pulling film thereto as needed during each wrapping cycle, means for supporting a supply of film, and a feed mechanism for drawing film from the supply and feeding the film to the wrapping mechanism, said feed mechanism comprising a stripper roll, movable means for maintaining tension on the film and for forming a reserve supply loop of film, continuously moving drive chain means, sprocket means connected to said stripper roll and adapted to be driven by said drive chain means when engaged thereby, and actuator means connected between said movable means and one of said drive chain and sprocket means for effecting engagement of said drive chain and sprocket means when said reserve supply loop of film has been depleted to a predetermined length and for effecting disengagement of said drive chain and sprocket means when said reserve supply loop of film has been replenished to another predetermined length.

12. Apparatus as in claim 11, and further including a plurality of friction bands fastened to the outer periphery of said stripper roll, said friction bands being made of silicone sponge.