The present invention relates to a method and apparatus for wrapping a load with packaging material.
Loads have been stretch wrapped with stretch wrap packaging material by securing a leading end of the packaging material to the load or a turntable clamp, dispensing the packaging material by providing relative rotation between the load and a packaging material dispenser to cause the load to be enveloped by the packaging material, and severing the packaging material between the load and a packaging material dispenser. The relative rotation between the load and the dispenser can be provided either by rotating the load on a turntable, or by rotating the dispenser around a stationary load. Stretch wrapping usually employs a web of stretch film as the packaging material, and the machinery can be either automatic or semi-automatic.
Semi-automatic stretch wrapping machinery requires the operator to attach a leading end of the packaging material to the load for each load to be wrapped. This is typically accomplished by forming a rope in the leading end of the film and then inserting this end between the layers of the load or by tying the end of the packaging material to the edge of the supporting wood pallet or any suitable outcropping on the load. This attachment must be relatively strong since it provides the reaction to force needed to pull the film from the film dispenser during the initiation of the relative rotation between the load and the film dispenser. The attachment or tying of the film makes film removal more difficult after the load has been shipped to its destination.
Automatic stretch wrapping machines are significantly more expensive than semi-automatic machines. The automatic machines typically use film clamps that grip the film web between two opposed surfaces, use electrical or pneumatic actuators to open and close the clamps, typically supply electrical or pneumatic power to the actuators on a turntable through the journal of the turntable, and use hot wires or other expensive cutting devices to cut the film. Such film clamps create a “tenting” effect during wrapping due to the distance between the clamp and the load during wrapping, resulting in wasted film and loosely wrapped loads.
In light of the cost of such automatic machines, there is a need for a method and apparatus for wrapping a load with packaging material that operates as effectively as those previously developed to allow automatic release and clamping of portions of the packaging material but which can be manufactured at a lower cost.
Accordingly, the present invention is directed to a method and apparatus for wrapping a load with packaging material which provides advantages over and obviates several problems associated with earlier methods and apparatus for wrapping a load.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention concerns an apparatus for wrapping a load with packaging material, including a dispenser for dispensing packaging material, a rotatable turntable for providing relative rotation between the dispenser and the load to wrap packaging material around the load, and a packaging material holder mounted on the turntable and isolated from any electrical or fluid power source by the rotatable turntable for automatically grasping and releasing portions of the packaging material.
According to another aspect of the present invention, the invention concerns an apparatus for wrapping a load with packaging material, including a dispenser for dispensing packaging material, means for providing relative rotation between the dispenser and the load to wrap packaging material around the load, and a packaging material holder for holding and releasing the packaging material, the packaging material holder being mounted to move upstream with the packaging material in response to force exerted on the packaging material by the packaging material holder to permit the packaging material to sever at a weakened portion between the packaging material holder and the load.
According to a further aspect of the present invention, there is provided a method of wrapping a load with packaging material, including grasping a leading end of packaging material with a packaging material holder mounted on a rotatable turntable and isolated from any electrical or fluid power source by the rotatable turntable, dispensing packaging material from a packaging material dispenser and rotating the turntable to wrap packaging material around the sides of the load, automatically releasing the leading end of the packaging material from the packaging material holder, and automatically grasping a trailing end of the packaging material with the packaging material holder at a point upstream of the leading end.
According to another aspect of the present invention, a method of wrapping a load with packaging material is provided including dispensing packaging material from a packaging material dispenser and providing relative rotation between the dispenser and the load to wrap packaging material around the sides of the load, holding a portion of the packaging material in a packaging material holder, weakening the packaging material between the load and the packaging material dispenser, and severing the packaging material at the weakened portion by tensioning the packaging material between the packaging material dispenser and the load while permitting the packaging material holder to move upstream with the packaging material toward the dispenser.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and other advantages of the invention will be realized and attained by the method and apparatus particularly pointed out in the written description and claims as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and together with the description serve to explain the principles of the invention.
The following text and accompanying drawings illustrate examples of the present preferred embodiments of the present invention.
According to the invention, an apparatus is provided for wrapping a load with packaging material. As embodied herein and shown in
As shown in
In a preferred embodiment, stretch wrap packaging material is used. In the stretch wrapping art, stretch wrap packaging material is known to have a high yield coefficient to allow the material a large amount of stretch during wrapping. Various other packaging materials, generally not considered to be stretch wrap materials, such as netting, strapping, banding, and tape, can be used as well. Dispenser 102 may also include a variety of rollers, optionally including prestretch rollers for stretching the packaging material longitudinally and/or transversely, to position, dispense, and stretch the packaging material as packaging material 116 is being dispensed from the roll of packaging material.
As shown in
Although not shown here, turntable assembly 120 may include an upper conveying surface with a plurality of powered rollers. As an alternative to the turntable embodiment, relative rotation may be accomplished by rotating dispenser 102 around a stationary load.
According to the present invention, a packaging material holder for automatically releasing and grasping portions of the packaging material is provided. As embodied herein and shown in
The clamp for holding and releasing packaging material 116, as shown in
As shown in
As embodied herein, the mechanical movement also includes a cam follower 158, which allows jaws 112, 114 to travel on the paths 152, 154 of ramp 150. As shown in
As embodied herein, the mechanical movement includes a cog mechanism 132 that rotates with packaging material holder 110 as turntable 122 rotates. Cog mechanism 132 consists of an engaging element 134 and a chain element 136. Chain element 136 forms a complete loop, connected at each of its ends to engaging element 134. Chain element 136 engages gears placed along the length of packaging material holder 110, and is moveable along the length of packaging material holder 110.
As embodied herein, an actuator for the mechanical movement is provided. Preferably, the actuator is positioned apart from rotatable turntable 122 and the mechanical movement, so that the actuator does not rotate with rotatable turntable 122. As shown, the actuator includes a pin 130. Engaging element 134 engages and is driven by pin 130 attached to the non-rotating portion of turntable assembly 120. Pin 130 is moveable between a non-upright position and an upright position, and pin 130 may be actuated to move to the upright position by a controller. In the upright position, pin 130 engages engaging element 134 of cog 132 as cog 132 rotates with rotatable turntable 122, driving cog 132 in a direction opposite to that of the rotation. As cog 132 is driven along the length of ramp 150 of packaging material holder 110, jaws 112, 114 of packaging material holder 110 move along the length of ramp 150 in the opposite direction, driven along the downstream path 152.
Cog element 132 also includes a release element 138 attached to rotatable surface 122 of turntable 120. Release element 138 is positioned at the upstream end of packaging material holder 110. Release element 138 is positioned to knock down or disengage pin 130 from cog 132 once cog 132 has moved from the downstream end of packaging material holder 110 to the upstream end of packaging material holder 110. As the length of packaging material holder 110 defines the full range of movement for cog 132, it is necessary to have a release once cog 132 has reached the end of its range of motion. Release element 138 serves this purpose.
Jaws 112, 114 of packaging material holder 110 move along upstream path 154 after it has reached the end of downstream path 152. Cam follower 158 is pulled along upstream path 154 by the force exerted upon packaging material 116 held in jaws 112, 114 by the roll of packaging material in dispenser 102. As shown in
As discussed above, packaging material holder 110 is mounted on the top surface of rotatable turntable 122, and jaws 112, 114 of packaging material holder 110 are actuated to automatically open and close at predetermined points along the length of ramp 150 of packaging material holder 110. As embodied herein, packaging material holder 110 is isolated from any electrical or fluid source of power by the turntable, in contrast to conventional devices in which the packaging material holder is connected to an electrical or fluid source of power by the turntable such as by a power connection through the journal of the turntable to the packaging material holder. This means that the packaging material holder also does not receive any electrical or fluid power from brushes, or the like, around a circumference of the turntable. The rotatable turntable 122 therefore does not carry electrical or fluid power sources with it during rotation and acts as a barrier between the packaging material holder and any electrical or fluid source of power.
This enables the present invention to take advantage of the changing of the angle of the packaging material relative to the load as the turntable rotates. The rotation of the turntable is harnessed to linearly move the packaging material holder along the turntable surface. During the last rotation of the turntable, as the angle becomes smaller and the packaging material approaches the side of the load, the packaging material holder is driven by the rotation of the turntable into a position to engage the trailing end of the packaging material.
In a preferred embodiment, as shown in
Other mechanical movements including various combinations of mechanical or electrical devices may be used to cause movement and opening and closing of jaws 112, 114. Alternatively, turntable 122 may not rotate while the packaging material is automatically released and grasped by the packaging material holder. In such a situation, packaging material holder 110 could be powered by a separate power source such as a motor placed on the floor or near the turntable.
According to one aspect of the invention, a roper may be provided for forming a rope of packaging material. As discussed herein, “roping” packaging material means rolling or twisting or collapsing a portion of the web of packaging material 116 to shape it into a rope-like form. In order to withstand a starting force during wrapping, at least 20% of the web of packaging material 116 should be held by the packaging material holder. For example, a web of packaging material twenty (20) inches high may have a five (5) or six (6) inch portion formed into a rope. This allows the jaws 112, 114 to engage a rope 118 and a portion of the web of packaging material 116, rather than holding only a small portion of the packaging material 116 between the opposing surfaces. As seen in
Although the present invention, as embodied herein, uses a scoop for roping, it is possible to use a wheel to roll the lower edge of the packaging material upward to form a rope of packaging material or to use a combination of a scoop and a wheel. Alternatively, other means such as a ramp may be used to gather the packaging material together to form a rope.
A positioner may be provided for passing the packaging material over the packaging material holder during wrapping. As embodied herein and shown in
As embodied herein and shown in
According to one aspect of the present invention, the apparatus may include means for securing a trailing end of packaging material to the load. As embodied herein, the means for securing includes a film wipedown mechanism for wiping a film tail onto the load after the packaging material has been cut. As shown in
Other cutters and wipedown arrangements may also be used.
A method for wrapping a load according to the present invention is shown in
Rotatable turntable 122 begins to rotate and packaging material 116 is dispensed from dispenser 102 about load 124. As packaging material 116 passes over packaging material holder 110, wheel 41 engages the lower edge of the packaging material, ensuring that the packaging material passes over packaging material holder 110 and does not become caught on it. This avoids a “tenting” effect and allows tight wrapping of the load. Load 124 is spirally wrapped with packaging material 116 as dispenser 102 moves vertically along mast 104 as the relative rotation is provided.
As the load is wrapped and rotatable turntable 122 enters the last rotation of the wrapping cycle, see
As cog 132 moves, the movement causes cam follower 158 to move up onto the top of ramp 150, to the start of downstream path 152. When cam follower 158 moves to the top of ramp 150, jaws 112, 114 open, automatically releasing leading end portion 30 of packaging material 116 (see
As cog 132 moves, it drives jaws 112, 114 downstream along a downstream path 152 of ramp 150. Concurrently, scooping element 140 begins to move from a retracted position to an upright position, scooping a trailing end 32 of packaging material 116 into a rope 118. As jaws 112, 114 continue to move downstream, they remain open, receiving trailing end 32 of packaging material 116 formed into rope 118 as scooping element 140 reaches its full upright position (see
As scooping element 140 is moving from the retracted position to the full upright position (see
Once jaws 112, 114 have reached the downstream end of packaging material holder 110, they grasp and hold trailing end 32 of packaging material 116. Packaging material 116 extends between dispenser 102, jaws 112, 114, and load 124. The tension in packaging material 116 between dispenser 102 and jaws 112, 114 causes jaws 112, 114 to move upstream toward the dispenser (see
Other arrangements for permitting the packaging material holder to move upstream with the packaging material toward the dispenser may also be provided.
Although the arrangement illustrated in the drawings weakens and then breaks the packaging material between the load and the jaws, it is in the scope of the one aspect of the invention to weaken the film somewhere between the dispenser and the load, and then break the film between the jaws and the load. Additionally, it is possible to simply sever the packaging material, as opposed to weakening and then breaking the packaging material.
All of the functions can be controlled with a conventional microprocessor, electromechanical controller, or other controller devices which are conventionally used with the stretch wrapping apparatus.
The present invention as embodied herein and described above, allows fully automated wrapping of loads at a drastically reduced cost and in an extremely efficient manner. The simplicity of the apparatus and its function allows existing rotary stretch wrapping apparatus to be retrofit to become fully automated. By using the rotation of the turntable to facilitate the releasing, grasping, and cutting of the packaging material, the need to supply power through the rotatable turntable of the turntable assembly to the packaging material holder and the need for expensive timing circuits is eliminated.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover all modifications and variations of this invention that come within the scope of the appended claims and their equivalents.
This application is a continuation of application Ser. No. 10/202,440, filed Jul. 25, 2002, now U.S. Pat. No. 6,848,237, which is a continuation of application Ser. No. 09/768,338, filed Jan. 25, 2001, now U.S. Pat. No. 6,449,922, which is a continuation of application Ser. No. 09/137,119, filed Aug. 20, 1998, now U.S. Pat. No. 6,269,610, all of which are incorporated herein by reference.
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Number | Date | Country | |
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20050183390 A1 | Aug 2005 | US |
Number | Date | Country | |
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Parent | 10202440 | Jul 2002 | US |
Child | 11029472 | US | |
Parent | 09768338 | Jan 2001 | US |
Child | 10202440 | US | |
Parent | 09137119 | Aug 1998 | US |
Child | 09768338 | US |