GB1594340A

GB1594340A - Guided stretch-wrap machine

Info

Publication number: GB1594340A
Application number: GB5218477A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-12-20
Filing date: 1977-12-15
Publication date: 1981-07-30
Also published as: DE2756850A1; JPS5391892A; CA1076947A; JPS5729323B2; DE2756850C2

Description

(54) GUIDED STRETCH-WRAP MACHINE (71) I, JOSEPH GOLDSTEIN, a Citizen of the United States of America, residing at 9838 Chicopee Avenue, Northridge, California, United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is directed to a stretch-wrap machine wherein a motive unit carries a stretch-wrap unit around material to be wrapped.

Modern mechanized handling requires that a number of small packages be packed together so that they can be handled in larger units. Pallets are used as a base, and packages are stacked on the pallet to a convenient size and weight for mechanical handling.

One approach to retaining the packages on the pallet has been steel banding. Steel bands were placed around the packages and the pallet and the bands tightened and clamped.

The problem with steel banding is that loads can shift, and under the wrong circumstances, all the packages on the outer extremities of the load directly under the steel bands can be crushed. Furthermore, the steel bands are difficult and dangerous to handle.

Steel bands are most useful on heavy metal objects, such as pipe and other forms of steel.

It must be noted that steel banding does not provide any weather protection for the packages.

A newer method of securing packages on a pallet to provide a palletized load is to shrink wrap the packages and the pallet. In this arrangement, bags are made out of shrink material (usually polyethylene), and the bag is placed over the palletized packages. Thereupon, the bag is subjected to heat whereupon it shrinks to unitize the palletized load.

Shrink wrap is useful for loads which are of uniform size, but requires special equipment for causing the shrinkage. Since heat is used to cause the shrinkage, it cannot be used in cold rooms or other areas where high heat loads are objectionable. Furthermore, it cannot be used over polyethylene wrapped packages because of sticking between the shrink wrap material and such packages.

To overcome these disadvantages, stretchwrapping has been developed. In these machines, one of which is seen in Lancaster Patent 3,867,806 a stack of packages is placed on a turntable. Usually, these packages are mounted on a pallet. The turntable is rotated, and the palletized load of packages is wrapped with a stretch-wrap material. This material may be polyethylene or polyvinylchloride web or film and is manufactured to be able to stretch at least 25 percent. During wrapping of the load, tension on the stretchwrap film provides a tension which stretches the film from 15 to 25 percent. The film is thin, usually about 1/1000th of an inch, and the load is wrapped with as many thicknesses as is necessary to obtain the desired unitized load strength.

The stretch-wrap film may be as tall as the load or may be narrower than the height of the load. In the latter case, the narrower film is spiral-wrapped around the load. Since more wraps are necessary at the top and bottom of the load than at the middle for best strength, this is more economical of material.

However, these stretch-wrapped concepts have been limited to those loads which can be placed on the turntable and rotated.

It is thus an object of this invention to provide a guided stretch-wrap machine which is capable of moving around material to be wrapped so that the stretch-wrap on the motive unit can be released with controlled tension to wrap stationary material loads. It is a further object to provide a stretch-wrap machine wherein the stretch wrap unit is moved around the structure of material to be packaged with the wrap while the material to be wrapped stands stationary.

According to the present invention there is provided a stretch-wrap machine comprising a vehicle including as components of the vehicle, means for supporting the vehicle for free movement along the floor, means for driving the vehicle along the floor around material to be wrapped, said supporting means including means for continually biasing the vehicle to move in a direction toward said material without external guidance, and feeler means projecting in said direction for engaging a surface associated with said material in response to said biasing and thereby limiting the movement of the vehicle toward said material, and a stretch-wrap unit mounted on the vehicle for movement therewith along the floor and including means for wrapping stretch-wrap film around the material to be wrapped as the vehicle travels on the floor around said material.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of the stretch-wrap machine of this invention.

FIGURE 2 is a top plan view of the stretch-wrap machine of FIGURE 1 with parts broken away to show the steering mechanism.

FIGURE 3 is a top plan view similar to FIGURE 2, but showing the stretch-wrap machine starting around a corner of the material to be wrapped, by means of its selfguidance.

FIGURE 4 is an enlarged elevational view, with parts broken away, taken generally along the line 15 15 of FIGURE 2.

A stretch-wrap machine 10 in accordance with the invention is shown in FIGURES 1, 2 and 3. The stretch-wrap machine 10 comprises motive unit 12 and stretch-wrap unit 14. The stretch-wrap unit is mounted on the motive unit, and the purpose of the motor unit is to move the stretch-wrap unit around the material to be wrapped. In FIGURES 1, 2 and 3, the material to be wrapped is indicated at 38 and, in FIGURE 4, it is illustrated as being positioned on pallet 39.

The material to be wrapped can be a wide variety of different types, from one large carton which needs strengthening, waterproofing, or securement to its pallet, or may be a stack of smaller cartons or bags which need to be held together and/or also held onto a pallet to make the load stable. On the other hand, the material to be wrapped may not be packaged, but may be furniture or the like which needs to be wrapped to protect it in storage or shipping. The material to be wrapped is placed on the floor 21, see FIGURES 1 and 4, and is positioned away from walls, posts, or other equipment sufficiently far that the stretch-wrap machine 10 can move around it.

Stretch-wrap unit 14 is illustrated as carrying roll 23 of stretch-wrap film 25. The stretch-wrap unit releases film 25 with appropriate tension as the motor unit carries the stretch-wrap unit around the material to be wrapped. When the width of film 25 in the height direction is sufficient to properly wrap the material to be wrapped, then no spiral traverse of the stretch-wrap roll is required.

However, for illustrative purposes, rails 27 carry carriage 29 upon which roll 23 is mounted for tensioned release. Motor 31 moves the carriage along its rails as the motor unit moves so that spiral wrapping is achieved, as indicated in FIGURE 1. In this way, wrapping of a tall load of material to be wrapped is accomplished. Control cabinet 33 houses the controls for the various motors and control of the tension, if such is required.

Motive unit 12 is supported on four wheels. The rear wheels 35 and 37 are mounted on axle 39, which is mounted on bearings on the bottom of platform 41 of the motive unit. Motor 43, see FIGURES 1 and 2 is connected through reduction gear 45 and belt or chain 47 to drive axle 39. Motor 43 is controlled by appropriate controls in control cabinet 35. The switches and knobs on the cabinet can control the on-off function of the motor and the speed at which it propels the motive unit.

Batteries may be provided in housings 41a to supply power to the propulsion motor, the stretch-wrap carriage motor, and the control so that the stretch-wrap machine is selfpowered and is completely independent of any external power supply.

Only left rear wheel 35 is keyed to axle 39, as by key 49. Wheel 37 is freely rotatable on the axle so that the propulsion of the motive unit tends to urge the motive unit in a clockwise circle when the motor unit moves to the left, as seen in FIGURE 2. Other motive means can accomplish this result. For example, the right rear wheel can be a caster, while belt 47 directly engages a pulley on the inside of wheel 35, which would be freely rotatable on a stub shaft. On the other hand, both rear wheels could be driven but with much higher propulsion force on the left rear wheel 35 than on the right rear wheel 37 by the use of a special, unbalanced differential.

Such a differential could place any desired fraction of the propulsion force on the left rear wheel, but the right rear wheel could also contribute toward motivation to optimize stretch-wrap tensioning.

Front axle 51 is pivoted on vertical steering pivot pin 53 on the bottom of platform 41 adjacent the front end thereof. Front wheels 55 and 57 are freely rotatably mounted on the front axle. Spring 59 is connected to the axle to bias the axle to urge it to steer the motive unit to make clockwise circles, as shown in FIGURE 3. Thus, steering is biased in the same direction as is the propulsion of the motive unit. In the preferred embodiment thus described, both the propulsion and steering are biased for turning the motive unit.

Feeler arm 61 carries follower roller 63 on the front end thereof. The arm is configured so that follower roller 63 is positioned to follow along the side of the material 38 to be wrapped and counteract the clockwise turning moment provided both by the propulsion unit and the bias steering. Roller 63 engages the side of the material 38 in response to the biasing of the motive unit toward the material and provides a counteractive force which limits the movement of the motive unit toward material 38 and causes the motive unit to follow along the side of the material 38 without further turning toward it. Any further turning toward it would cause the follower roller 63 to turn the steering wheels out so that the motive unit is self-guided from the material 38. The straight-ahead direction along the straight edge of the material 38 is shown in FIGURES 1 and 2.

FIGURE 3 shows that when follower roller 63 reaches the corner, the bias of the steering and the bias of the propulsion causes the motive unit to immediately turn around the corner. In this way, the motive unit carries the stretch-wrap unit around and around the material 38 to be wrapped. As the motive unit is driven along the floor around the material to be wrapped, either by the propulsion alone or in conjunction with the steering, it is clear that the stretch-wrap film wraps the material for its secure packaging and protection.

Switch 65 is positioned on the underside of platform 41 and has dog 67 extending from the bottom thereof. This dog is contacted by feeler arm 61 each time the feeler arm and the steering turn far enough for the stretchwrap machine to go around a corner, as shown in FIGURE 3. Switch 65 is connected into control cabinet 33 wherein the corners are counted. When the desired number of corners has been negotiated so that stretchwrapping is complete, the machine can thus shut itself off. In this way, stopping can be automatically accomplished.

In some cases, the material to be wrapped does not have corners or is oddly configured so that the corner-counting switch 65 is not applicable. Accordingly, arm 61 is provided with a sensor or switch 66 depending therefrom and adapted to make contact with a switch actuator block 21a. Thus, block 21a is disposed between the path of the motive unit and the material to be wrapped so that arm 61 passes over block 21 a once per wrapping revolution or turn. Switch 61a which is actuated by such passing contact, is connected into control cabinet 33 wherein the revolutions or turns are counted so that the machine can shut itself off when the stretchwrapping is completed.It should be noted that the location of switch 61 a on arm 61 is for ease and convenience, since sensor or switch 61 a also may be locatable on an auxiliary arm mounted on the motive unit and directed to port or starboard with respect to the motive unit so as to pass over the appropriately located actuator block 21 a.

Also, other conventional sensing means, including optical and electromagnetic, for example, can be used instead of switches 65 or 61 a, with corresponding changes in the actuatory therefor.

In view of the fact that different materials to be wrapped may have different characteristics adjacent their lower edge for the follower roller to follow, the follower roller 63 can be provided with vertical adjustment.

As is seen in FIGURE 4, adjustable leg 69 has floor-following roller 71 on the bottom thereof. By adjusting the height of leg 69, the height of follower roller 63 above the floor is adjusted. When the load is palletized, of course, follower roller 63 must be above the pallet openings.

WHAT I CLAIM IS: 1. A stretch-wrap machine comprising: a vehicle including, as components of the vehicle, means for supporting the vehicle for free movement along the floor, means for driving the vehicle along the floor around material to be wrapped, said supporting means including means for continually biasing the vehicle to move in a direction toward said material without external guidance, and feeler means projecting in said direction for engaging a surface associated with said material in response to said biasing and thereby limiting the movement of the vehicle toward said material, and a stretchwrap unit mounted on the vehicle for movement therewith along the floor and including means for wrapping stretch-wrap film around the material to be wrapped as the vehicle travels on the floor around said material.

2. A stretch-wrap machine as claimed in Claim 1, wherein said feeler means projects from one side of the vehicle and said means for supporting the vehicle comprises a propulsion wheel on the opposite side of the vehicle, and wherein said driving means, including said biasing means, comprises means for propelling said wheel.

3. A stretch-wrap machine as claimed in Claim 2, wherein said means for supporting the vehicle also comprises an additional wheel at said one side of the vehicle.

4. A stretch-wrap machine as claimed in Claim 1, wherein said means for supporting the vehicle comprises at least one propulsion wheel and at least one steerable wheel, and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. shown in FIGURE 3. Thus, steering is biased in the same direction as is the propulsion of the motive unit. In the preferred embodiment thus described, both the propulsion and steering are biased for turning the motive unit. Feeler arm 61 carries follower roller 63 on the front end thereof. The arm is configured so that follower roller 63 is positioned to follow along the side of the material 38 to be wrapped and counteract the clockwise turning moment provided both by the propulsion unit and the bias steering. Roller 63 engages the side of the material 38 in response to the biasing of the motive unit toward the material and provides a counteractive force which limits the movement of the motive unit toward material 38 and causes the motive unit to follow along the side of the material 38 without further turning toward it. Any further turning toward it would cause the follower roller 63 to turn the steering wheels out so that the motive unit is self-guided from the material 38. The straight-ahead direction along the straight edge of the material 38 is shown in FIGURES 1 and 2. FIGURE 3 shows that when follower roller 63 reaches the corner, the bias of the steering and the bias of the propulsion causes the motive unit to immediately turn around the corner. In this way, the motive unit carries the stretch-wrap unit around and around the material 38 to be wrapped. As the motive unit is driven along the floor around the material to be wrapped, either by the propulsion alone or in conjunction with the steering, it is clear that the stretch-wrap film wraps the material for its secure packaging and protection. Switch 65 is positioned on the underside of platform 41 and has dog 67 extending from the bottom thereof. This dog is contacted by feeler arm 61 each time the feeler arm and the steering turn far enough for the stretchwrap machine to go around a corner, as shown in FIGURE 3. Switch 65 is connected into control cabinet 33 wherein the corners are counted. When the desired number of corners has been negotiated so that stretchwrapping is complete, the machine can thus shut itself off. In this way, stopping can be automatically accomplished. In some cases, the material to be wrapped does not have corners or is oddly configured so that the corner-counting switch 65 is not applicable. Accordingly, arm 61 is provided with a sensor or switch 66 depending therefrom and adapted to make contact with a switch actuator block 21a. Thus, block 21a is disposed between the path of the motive unit and the material to be wrapped so that arm 61 passes over block 21 a once per wrapping revolution or turn. Switch 61a which is actuated by such passing contact, is connected into control cabinet 33 wherein the revolutions or turns are counted so that the machine can shut itself off when the stretchwrapping is completed.It should be noted that the location of switch 61 a on arm 61 is for ease and convenience, since sensor or switch 61 a also may be locatable on an auxiliary arm mounted on the motive unit and directed to port or starboard with respect to the motive unit so as to pass over the appropriately located actuator block 21 a. Also, other conventional sensing means, including optical and electromagnetic, for example, can be used instead of switches 65 or 61 a, with corresponding changes in the actuatory therefor. In view of the fact that different materials to be wrapped may have different characteristics adjacent their lower edge for the follower roller to follow, the follower roller 63 can be provided with vertical adjustment. As is seen in FIGURE 4, adjustable leg 69 has floor-following roller 71 on the bottom thereof. By adjusting the height of leg 69, the height of follower roller 63 above the floor is adjusted. When the load is palletized, of course, follower roller 63 must be above the pallet openings. WHAT I CLAIM IS:

1. A stretch-wrap machine comprising: a vehicle including, as components of the vehicle, means for supporting the vehicle for free movement along the floor, means for driving the vehicle along the floor around material to be wrapped, said supporting means including means for continually biasing the vehicle to move in a direction toward said material without external guidance, and feeler means projecting in said direction for engaging a surface associated with said material in response to said biasing and thereby limiting the movement of the vehicle toward said material, and a stretchwrap unit mounted on the vehicle for movement therewith along the floor and including means for wrapping stretch-wrap film around the material to be wrapped as the vehicle travels on the floor around said material.

wherein said means for driving the vehicle comprise means for propelling said propulsion wheel, said biasing means comprising means for urging said steerable wheel to steer toward the material to be wrapped.

5. A stretch-wrap machine as claimed in Claim 4, further comprising means connecting said feeler means to said steerable wheel for steering said steerable wheel in accordance with the shape of said surface engaged by said feeler means.

6. A stretch-wrap machine as claimed in Claim 4, wherein said biasing means comprises a spring connected to said steerable wheel.

7. A stretch-wrap machine as claimed in Claim 1, wherein said feeler means has a roller for engaging said surface.

8. A stretch-wrap machine as claimed in Claim 7, wherein said roller is of adjustable height to adjust the level at which the roller engages said surface.

9. A stretch-wrap machine as claimed in Claim 1, further comprising means for counting the number of revolutions of said vehicle about the material to be wrapped.

10. A stretch-wrap machine as claimed in Claim 9, wherein said counting means comprises means for counting the number of corners of the material to be wrapped that are passed by the vehicle.

11. A stretch-wrap machine as claimed in Claim 10, wherein said means for supporting the vehicle comprises a steerable wheel, wherein said biasing means comprises means for urging said wheel to steer in a direction toward the material to be wrapped, and wherein said counting means comprises means responsive to the steering of said wheel as the vehicle passes a corner of the material to be wrapped.

12. A stretch-wrap machine as claimed in Claim 9, wherein said counting means comprises a sensor mounted on said vehicle and a sensor actuator fixed relative to the material to be wrapped and positioned to actuate the sensor each time the vehicle has completed a revolution about the material to be wrapped.

13. A stretch-wrap machine, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.