93results about "Prestretching mechanism" patented technology

The present invention provides a method and apparatus for dispensing a predetermined substantially constant length of pre-stretched packaging material based upon load girth. Based upon the girth of the load to be wrapped, an amount of pre-stretched packaging material to be dispensed for each revolution of relative rotation between a packaging material dispenser and the load is determined. A rotational drive system used to provide the relative rotation is linked to a pre-stretch assembly portion of the packaging material dispenser. The linkage may be mechanical or electrical. The linkage controls a ratio of the rotational speed to the pre-stretch assembly dispensing speed, such that the predetermined substantially constant length of pre-stretched packaging material is dispensed for each revolution of the packaging material dispenser relative to the load regardless of the speed of the rotational drive. In the case of a mechanical linkage, the linkage also connects the rotational drive to the pre-stretch assembly portion such that the rotational drive also drives the pre-stretch assembly portion.

A control system for a wrapping apparatus may include a packaging material dispenser configured to dispense packaging material for wrapping a load. The control system may also include at least one sensor assembly configured to generate a signal based on instantaneous demand for packaging material at the load. The control system may further include a controller configured to control operation of the packaging material dispenser based at least in part on the signal.

The present invention provides a method and apparatus for dispensing a predetermined fixed amount of pre-stretched packaging material based upon load girth. A non-rotating ring carries a belt driven by a motor. A packaging material dispenser is mounted on a rotating ring, and the rotating ring may include a pulley that connects to the band, such that the rotating ring is driven by the drive belt. Based upon the girth of the load to be wrapped, an amount of pre-stretched packaging material to be dispensed for each revolution made by the rotating ring is determined. Good wrapping performance in terms of load containment (wrap force) and optimum packaging material use is obtained by dispensing a length of pre-stretched packaging material that is between approximately 90% and approximately 120% of load girth. Once the amount of packaging material to be dispensed per revolution is determined, a ratio of rotating ring drive to final pre-stretch surface speed (i.e., number of pre-stretch roller revolution/rotating ring rotation) can be set and mechanically controlled. Thus, for each revolution of the rotating ring and dispenser, a predetermined fixed amount of packaging material is dispensed and wrapped around the load. In an alternative embodiment, the ratio is electronically controlled.

A film dispenser for a stretch wrapping apparatus is provided. The film dispenser includes a pre-stretch assembly having a top portion mounted to and extending downwardly from a drive plate of a roll carriage frame. The pre-stretch assembly includes two pre-stretch rollers having first ends connected to the roll carriage frame and second ends connected to one another. The pre-stretch rollers may be coated. The pre-stretch assembly further includes a cantilevered idle roller mounted to the drive plate and positioned between the pre-stretch rollers. A film path is defined by the space between the pre-stretch rollers and the idle roller. The film path is easily accessible via the bottom end of the pre-stretch assembly.

The present invention provides a method and apparatus for dispensing a predetermined fixed amount of pre-stretched film based upon load girth. A non-rotating ring carries a belt driven by a motor. A film dispenser is mounted on a rotating ring, and the rotating ring includes a pulley that connects to the belt, such that the rotating ring is driven by the belt. Based upon the girth of the load to be wrapped, an amount of pre-stretched film to be dispensed for each revolution made by the rotating ring is determined. Good wrapping performance in terms of load containment (wrap force) and optimum film use is obtained by dispensing a length of pre-stretched film that is between approximately 100% and approximately 130% of load girth. Once the amount of film to be dispensed per revolution is determined, a mechanical ratio of ring drive to final pre-stretch surface speed (i.e., number of pre-stretch roller revolution/ring rotation) can be set. Thus, for each revolution of the rotating ring and dispenser, a predetermined fixed amount of film is dispensed and wrapped around the load.

A machine for wrapping a load with a film made of synthetic plastics includes a first frame suitable for supporting second frame that rotatably supports around, and slidably parallel to, a wrapping axis at least one wrapping unit including a reel of the film and a roller assembly arranged for unwinding and prestretching the film. The second frame is slidably mounted on the first frame and is movable along an advancing direction that is transverse, and in particular orthogonal, to the wrapping axis. A conveyor is provided for moving the load along the advancing direction. The conveyor and the second frame are movable in a mutually coordinated manner to wrap the load with the film also while the load is moved along the advancing direction.

A stretch head for facilitating the wrapping of palletized loads within packaging or wrapping film comprises a vertical downright, and a carriage assembly vertically movable along the vertical downright. A base plate is mounted upon the carriage assembly and is inclined with respect to a horizontal plane so as to have a first end thereof disposed at a higher elevation than a second opposite end thereof. A supply roll of wrapping or packaging film is rotatably mounted upon the first higher end of the base plate, and a pair of tension rollers are mounted upon a substantially central portion of the base plate. A strain gauge roller is also mounted upon the base plate for receiving the wrapping film exiting from the tension rollers, a first idler roller is mounted upon the base plate for receiving the wrapping film from the strain gauge roller, and a second idler roller is mounted upon the second opposite end of the base plate for receiving the wrapping film from the first idler roller. Since the second idler roller is mounted upon the lowest end portion of the base plate, in view of the inclined disposition thereof, the second idler roller is capable of positioning the wrapping film at the lowest elevation whereby the wrapping film can be wrapped around the lowermost regions of the palletized load. The second idler roller also comprises a rubberized sleeve member for preventing movement of the wrapping film in an axial direction along the external periphery of the second idler roller so as to ensure proper positioning and orientation of the wrapping film with respect to the palletized load.

A method, apparatus and program product may determine load stability for a load to be wrapped based upon sensing the response or reaction of the load to a disturbance applied to the load, e.g., through intentionally moving, shaking, tilting, pushing, impacting or otherwise applying an input force to the load and sensing the response using one or more sensors. The sensed response may then be used to determine a load stability parameter that may be used in the control of a load wrapping apparatus when wrapping the load.

In one aspect, a stretch wrap system configured to separately wrap a plurality of loads in film comprising a plurality of stretch wrapping machines, each machine comprising at least one sensing mechanism configured to sense the presence of a load, and a control box electrically coupled to sensing mechanisms, the control box comprising a start button configured to start the machines when sensing mechanisms detect load. In another aspect, a process of operating a system for stretch wrapping comprising positioning at least one load to be wrapped in front of at least one of a first and second machine wherein the first machine includes a sensing mechanism electrically coupled to a control box and wherein the second machine includes a second sensing mechanism electrically coupled to the control box, inputting a start signal through the control box, transmitting a signal from the control box to each of the sensing mechanisms, determining the presence or absence of a load within an operational space of each of the plurality of stretch wrapping machines and wrapping each present load using a respective one of the plurality of stretch wrapping machines.

A method for wrapping a load with a film by a wrapping machine including an unwinding apparatus provided with a reel of the film includes moving the wrapping apparatus and the load in relation to one another and unwinding from the reel an established effective length of film per revolution of the wrapping apparatus or of the load. The established effective length of film is calculated with the formula: where: S_f. initial length of film is determined on the basis of dimension and/or shape of the load; w: rotation speed around a wrapping axis of the unwinding apparatus or of the load; V_t: movement speed of the unwinding apparatus parallel to the rotation axis; ^ωmax: maximum rotation speed around the wrapping axis of the unwinding apparatus or of the load; Δ_corr: corrective parameter.

A film delivery device comprising a first assembly (4) which can be connected to a wrapping machine and a second assembly (5) which is pivoted to turn, relative to the first assembly (4), about a horizontal hinge axis (6) between a closed position (I) and an open position (II). A first prestretch roller (7) is in the first assembly (4). A second prestretch roller (8) is in the second assembly (5). The film can be threaded by S-threading between the prestretch rollers (7, 8). The second assembly (5) is hinged at the lower end to the lower end of the first assembly (4) to turn about said horizontal hinge axis (6). The second assembly (5) comprises a pivoted and spring-loaded first deflecting roller (22) which is arranged downstream relative to the first prestretch roller (7). In the open position (II) of the second assembly (5), that part of the first deflecting roller (22) which is close to the lower end thereof is resting against the surface of the first prestretch roller (7).

Devices and method for accurately measuring the length of film feeding into a pre-stretch carriage from a supply roll and the length of film exiting after the pre-stretch carriage in order to accurately determine the actual percentage of film stretch occurring during the wrap cycle are provided. A first idler roller mounted on the frame of a pre-stretch carriage before the pre-stretching rollers and second idler roller mounted to the frame after the pre-stretching rollers are included. Optical rotary encoders are driven directly by idler roller shafts as stretch film passes around the shafts during film application. Systems including internet of things (HOT) devices can be fitted or retro fitted to a wide variety of stretch wrapping machines

A wrapping machine having a pre-stretching device for pre-stretching a film web drawn from film roll before its being wrapped around an object, said pre-stretching device including a first pre-stretching roller and a second pre-stretching roller, which are tractively coupled via power transmission gears. A first deflecting pinch roller has been fitted to be pressed against the first pre-stretching roller to form a first nip for the film web passed between the first deflecting pinch roller and the first pre-stretching roller. A second deflecting pinch roller has been fitted to be pressed against the second pre-stretching roller to form a second nip for the film web passed between the second deflecting pinch roller and the second pre-stretching roller. A lever mechanism moves the first pre-stretching roller between an engagement position and a disengagement position, so that the lever mechanism also moves the first deflecting pinch roller apart from the first pre-stretching roller and simultaneously the second deflecting pinch roller apart from the second pre-stretching roller to allow easier thread-in of the film web end.

A method, apparatus and program product perform automatic load profiling to optimize a wrapping operation performed with a stretch wrapping machine. Automatic load profiling may be performed, for example, to determine a density parameter for a load that is indicative of load stability such that one or more control parameters may be configured for a wrapping operation based upon the density parameter. Automatic load profiling may also be performed, for example, to detect a load with a nonstandard top layer, e.g., a load with a top or slip sheet, a load with an easily deformable top layer, a load with a ragged top surface topography and/or a load with an inboard portion, such that a top layer containment operation may be activated during wrapping to optimize containment for the load.

A method, apparatus and program product implement top layer containment operations to optimize containment of various types of loads such as loads with top/slip sheets, ragged topographies, and/or inboard portions. Bidirectional control of the elevation of a web of packaging material may be performed within one or more revolutions between a load and a packaging material dispenser to selectively engage one or more corners of the load with a web of packaging material while passing the web of packaging material inwardly of one or more other corners of the load.

A film packing device capable of replacing gears includes a handle. Two ends of the handle are provided with a coupling rod and a base, respectively. A film application unit and a pair of rollers are pivotally connected between the coupling rod and the base. Two ends of each roller are provided with an axle gear, respectively. The outer toothed portions of the axle gears mesh with a drive gear and a reduction gear, respectively. The drive gear meshes with the reduction gear. Through the outer toothed portions of the axle gears to mesh with the drive gear and the reduction gear, the drive gear and the reduction gear can be installed easily. The drive gear and the reduction gear having different numbers of teeth on the outer toothed portions thereof are selective so as to change the gear ratio thereof to provide a different binding force for packing.

A stretching device for a stretch wrap machine includes a support structure and a film support for rotatably holding a roll of stretchable film. First and second rollers are rotatably mounted to the support structure. The stretching device includes a take-off device for supporting film as it is fed from the stretching device. A power drive assembly includes a motor, and the power drive assembly is configured to rotate the first and second rollers to stretch a film between the rollers. The stretching device further includes an elongated flexible member forming a loop and having a connector adapted for securing stretchable film. A guide assembly adjacent first ends of the first and second rollers movably supports the elongated flexible member to guide stretchable film through the stretching device. A disengagable drive is operably coupled to the elongated flexible member to provide powered movement of the elongated flexible member. The drive member is disengagable from the motor such that the first and second rollers can be rotated under power while the elongated flexible member is disengaged from the motor. The stretching device may be utilized with wrapping machines having a rotatable base or a turntable, or with wrapping machines of the type having an arm that rotates to wrap film about packages. The stretching device may include a tensioning device that tensions the chain.