Abstract:
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.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is directed to a system and process for wrapping a plurality of loads to improve efficiency and increase the speed with which the loads can be wrapped and then transported. 
         [0003]    2. Description of the Related Art 
         [0004]    Stretch wrapping of loads on pallets used to be done by hand, with an operator unrolling the wrap, winding the wrap around the load, cutting the wrap and making sure it adhered to the load. This process was time consuming, inefficient and wasteful. 
         [0005]    In time, stretch wrapping machines were developed to speed up the process, automating each step described above. In addition, the machines could stretch the wrap, thereby pre-tensioning it, which has two benefits. First, a stretched wrap requires less wrap to fully encompass a load, meaning less material needs to be used per wrapping. Second, the pretensioning causes the wrap to pull inwards on itself, causing the load to be more securely wrapped, resulting in more stable transport. However, even with the use of stretch wrapping machines, if an operator wished to wrap more than one pallet of material at a time, he would have to set up each pallet in front of separate machines and control each machine separately or he would have to use a conveyorized system 
         [0006]    What is needed is a system and process for stretch wrapping that takes advantage of the benefits of stretch wrapping machines while further increasing their efficiency and productivity. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    In one aspect of the invention, a stretch wrap system configured to separately wrap a plurality of loads in film may have 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 the sensing mechanisms detect load. In one embodiment, each of the sensing mechanisms may be a photo eye. In addition, each sensing mechanism may further sense the height of the load. To do this, the sensing mechanisms may use one or more infrared light signals to determine the presence and height of the load by calculating the presence or lack of reflectivity or the time for reflection of the light signals. 
         [0008]    In another aspect of the invention, a process of operating a system for stretch wrapping having a plurality of stretch wrapping machines, the process 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 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 by a respective one of the plurality of stretch wrapping machines. This process may further include the step of determining a height of each present load within an operational space of each of the plurality of stretch wrapping machines. 
         [0009]    These and other features and advantages are evident from the following description of the present invention, with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of stretch wrapping system. 
           [0011]      FIG. 2  is a perspective view of a stretch wrapping machine of  FIG. 1 . 
           [0012]      FIG. 3  is a perspective view of a film cutting and wiping system. 
           [0013]      FIG. 4  is a perspective view of a revolving top frame used in the stretch wrap system of  FIG. 1 . 
           [0014]      FIG. 5  is a perspective view of a revolving boom arm used in the stretch wrap system of  FIG. 1 . 
           [0015]      FIG. 6  is an exploded view of a carriage used for housing, prestreching, and applying stretch wrap. 
           [0016]      FIG. 7  is an exploded view of a sensing apparatus and attachment mechanism. 
           [0017]      FIG. 8  is a schematic of a control box and sensing apparatus. 
           [0018]      FIG. 9  is a schematic of a control box and sensing apparatus. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Stretch wrap system  10  is a system configured to wrap at least one load on a pallet, a slipsheet, or other suitable surface, preferably more than one load substantially simultaneously, to increase wrapping efficiency by decreasing the time it takes a user to prepare, wrap and remove each load. System  10  includes at least one stretch wrap machine  100 , preferably a plurality of stretch wrap machines, still more preferably at least two stretch wrap machines  100  and  200 , and in one embodiment, system  10  may include at least three stretch wrap machines  100 ,  200  and  300 . In one embodiment, system  10  includes more than three stretch wrapping machines. System  10  is configured such that machines  100 ,  200  and/or  300  are in electrical communication such that one load  500 , two loads  500 ,  502  and/or three loads  500 ,  502 ,  504  may be wrapped in stretch film substantially simultaneously or in series. 
       Machine Components 
       [0020]    Referring to  FIG. 1 , machines  100 ,  200  and  300  may be positioned generally in line with each other. Preferably, machines  100 ,  200  and  300  may be positioned generally coaxially with one another along axis  12  such that the front  114 ,  214 ,  314  of each machine  100 ,  200  and  300  is configured to receive a load and fronts  114 ,  214 ,  314  are generally in line with each other. Machines  100 ,  200 , and/or  300  may be of similar size or have different sizes depending upon the size of the loads intended to be wrapped. 
         [0021]    In one embodiment, machines  100 ,  200  and  300  are positioned a distance D M  apart. Specifically, distance D M  is defined between the approximate centers of consecutive machine ring gears  167  (described herein). In one embodiment, distance D M  may be a distance between about 3′ and about 45′, preferably between about 10′ and about 30′, and more preferably about 12′. Distance D M  may be defined at least partially by the size of each load, the size of each machine, and the size of modular arm  164  (described herein) to prevent machines from damaging one another. Furthermore, a distance D L  is defined between consecutive load surfaces. For example, distance D L  is defined between outer surfaces of loads  500  and  502 , as shown in  FIG. 1 . In one embodiment, distance D L  may be a distance between about 1′ and about 50′, preferably between about 5′ and about 25′, and more preferably about 10′. Moreover, distance D L  may be defined at least partially by the size of each load, the size of each machine, and the size of modular arm  164  (described herein) to prevent machines from damaging one another and to enable enough space for the machines to properly stretch wrap each load such that system  10  operates as described herein. A timing sequence between the machines may be prearranged so that the machines do not interfere with the operation of one another when more than one machine is in operation. The timing sequence may enable machines to be placed closer together such that the wrap diameters of the machines overlap. Additionally, system  10  may include safety fencing  16 . The dimensions and position of safety fencing  16  may change based upon the layout of the plant and/or facility that houses system  10 . 
         [0022]    Referring to  FIG. 2 , at least one machine  100  includes a base  102  configured to be positioned on the ground and at least one stand  104  having a first end  106  and an opposing second end  108  wherein first end  106  is coupled to base  102 . In one embodiment, base  102  and stand  104  may be substantially perpendicular to one another. In one embodiment, stand  104  may have a height between about 50″ and about 200″, preferably between about 100″ and about 150″, and more preferably about 141″. Stand height  104  may vary depending upon the height of the load or the ‘wrap height’. For example, a wrap height of about 104″ may have a stand height of about 141″. In another embodiment, machine  100  may be a turntable stretch wrap machine wherein a load to be stretch wrapped would be placed upon a turntable. 
         [0023]    Referring to  FIG. 3 , system  10  includes at least one machine  100  that may include a stretch film wipe system  110 . In one embodiment, wipe system  110  is configured to cut and wipe stretch film  142  after machine  100  has completed a wrap cycle and wrapped load  500 . In one embodiment, wipe system  110  is coupled proximate stand first end  106 . Stretch film wipe system  110  is configured to eliminate the need to attach and cut film  142  manually, saving time and costs. Further, the wipe system  110  generally eliminates film tails. Specifically, wipe system  110  may include an attachment  112  that may be coupled to stand  104 , a substantially stationary arm  113  that may be coupled to attachment  112 , a movable arm  114  that may be coupled to stationary arm  113 , a heat impulse wire  116  and a wiper  118  that both may be coupled to arm  114  and may extend substantially perpendicular therefrom. Arm  114  is configured to extend out towards the load. After the wrap cycle is completed, heat impulse wire  116  turns on momentarily to cut the film  142 , and wiper  118  extends out to wipe film  142  on the pallet and/or the rest of the load  500 . Wiper  118  may be replaced with other items depending on the type of load being wrapped. For example, wiper  118  may be a brush (shown in  FIG. 3 ) when the load has flat, even sides. Wiper  118  may be a series of plastic bumpers (not shown), mounted one on top of another, when the load is irregularly shaped. In another embodiment, wipe system  110  may be any wipe system that performs the substantially same function. 
         [0024]    Turning to  FIG. 4 , which is a perspective view of a top frame  160  of machine  100 , top frame  160  may couple to at least one of a boom arm  120  (shown in  FIG. 5 ) and/or stand  104 . In one embodiment, top frame  160  has an upper portion  162  and a lower portion or modular arm  164 . Upper portion  120  has a first end  163  and an opposing second end  165  configured to couple to stand  104 , and modular arm  164  has a first end  166  and an opposing second end  168 . Top frame  160  also has a ring gear  167  coupled between upper portion  162  and modular arm  164  proximate first end  166  such that modular arm  164  may rotate with respect to upper portion  120 . In one embodiment, ring gear  167  is a belt drive. Specifically, ring gear  167  may rotate modular arm  164  along an axis  169  such that second end  168  rotates freely. In one embodiment, axis  169  is substantially parallel to stand  104 . As second end  168  rotates around axis  169 , it creates a wrap diameter (not shown). Wrap diameter is a function of the size of modular arm  164  and the size of the load. As such, the wrap diameter must be larger than the size of the load. In one embodiment, the wrap diameter may be between about 20″ and 100″, preferably between about 40″ and 80″, and, in one embodiment, about 68″. 
         [0025]    Machine  100  may further comprise a ring gear cover (not shown) configured to cover ring gear  167 . The ring gear cover may include a flange (not shown) configured to engage at least one of upper portion  162  and/or modular arm  164  when the cover is coupled to gear  167 . 
         [0026]    Referring to  FIG. 5 , machine  100  may also include a boom arm  120  that may include a film prestretch carriage holder  122  configured to hold a carriage  140  (shown in  FIG. 6 ) that may carry stretch film  142  and that may be coupled to second end  168  of modular arm  164 . Boom arm  120  may also include a motor and/or gear designed and configured to vary the position of carriage holder  122  and/or carriage  140 , for example, translationally between boom arm top  124  and boom arm bottom  126 . Specifically, boom arm  120  may raise carriage holder  122  and/or carriage  140  proximate the top of the load, may lower carriage holder  122  and/or carriage  140  proximate the bottom of the load, and/or may position carriage holder  122  and/or carriage  140  therebetween. Machine  100  may also include a bracket  128  having guides to facilitate maintaining carriage  140  substantially aligned with length of boom arm  120 . 
         [0027]    Machine  100  may further include an arm  132  and at least one photo eye  130  wherein arm  132  is preferably coupled near boom arm top  124 . Photo eye  130  may be a safety photo eye that is in electrical communication with machine  100  and may partially control the position of boom arm  120 , carriage holder  122 , and/or carriage  140 . Specifically, photo eye  130  emits an infrared beam of light that is intended to be detected by a reflector  136  coupled to a flexible plastic bumper  135  (shown in  FIG. 2 ), such that photo eye  130  generally is directed towards the reflector  136 . Bumper  135  is preferably coupled near boom arm bottom  126 . After photo eye  130  emits an infrared beam of light, if the infrared beam is interrupted, such that the infrared beam of light is not detected by the reflector  136 , a signal is transmitted to stop boom arm  120 . Alternatively, photo eye  130  may be a bumper to enhance the safety of machine  100 . 
         [0028]    Referring to  FIG. 6 , machine  100  also includes at least one prestretch carriage  140  configured to move along boom arm  120  to apply a spiraling layer of prestretched film  142  to the load to encapsulate the load in film  142 . Carriage  140  may be coupled to prestretch carriage holder  122  on boom arm  120 . 
         [0029]    In addition to applying a layer of film  142  to a load, prestretch carriage  140  is configured to stretch film  142  prior to applying film  142  to the load to be wrapped. Stretch film  142  passes through carriage  140 , threading past at least two rubber rollers, a primary roller  144  and a secondary roller  146 , with a distance  147  extending therebetween. Each roller  144  and  146  has a height  141  extending between a first end  143  and a second end  145  and are coupled together by a carriage top plate  148  and an opposing carriage bottom plate  149 . Height  141  may vary depending on the size of film  142 . A carriage cover  139  may be coupled to a portion of top plate  148  to at least partially cover the top of carriage  140 . 
         [0030]    Primary and secondary rollers  144  and  146  are generally rubberized rollers that film  142  passes by and are used to stretch film  142  prior to applying film  142  to the load. Secondary roller  146  is generally larger than primary roller  144  and may be designed to rotate generally faster primary roller  144 , for example through the use of a gear differential between primary roller  144  and secondary roller  146 . The speed differential of secondary roller  146  pulls film  142  from primary roller  144 , stretching film  142  between rollers  144  and  146  into prestretch film  142 . For example, prestretch carriage  140  may stretch approximately 10″ of film  142  into approximately 40″ of prestretch film  142 . Stretching film  142  prior to applying film  142  to the load decreases the amount of film  142  necessary to wrap the load and also activates the film memory effect causing film  142  to want to stretch back to its original length after it is applied to the load, thereby film  142  tightens around the load and securely holds the load. 
         [0031]    Prestretch carriage  140  may also include a prestretch carriage dancer bar assembly  151  including a dancer bar  153  that is loaded, preferably spring loaded, with a cam near top  155 . Dancer bar assembly  151  is configured to allow more film  142  to feed at corners of the load to prevent film  142  from tearing. Carriage  140  may include a sensor (not shown) that reads the distance between the cam and the sensor. As the cam moves further from the sensor, the prestretch carriage motor will turn faster thereby enabling carriage  140  to feed film  142  faster. Alternatively, switches and/or load cells may be used to vary the speed in which film  142  is fed. 
         [0032]    Additionally, prestretch carriage  140  may further have a film carriage door  190 . Door  190  is configured to push film  142  against rollers  144  and  146  to maintain contact between the film  142  and rollers  144  and  146  for prestretch tensile consistency. 
         [0033]    Staying with  FIG. 6 , prestretch carriage  140  may further include a top plate  148  and multiple gear belt pulleys  152 ,  154 ,  156 , and  158 . Gear belt pulley  152  may preferably have a slightly smaller bore than pulleys  154 ,  156 , and  158 . In one embodiment, the size of pulleys  154 ,  156 , and  158  have bores that are substantially the same size. Pulleys  152  may have a bore size between about 0.1 inch and about 2 inches, preferably between about 0.5 inch and 1.5 inches, and more preferably about 0.625 inch. Pulleys  154 ,  156 , and  158  each may have a bore size between about 0.1 inch and about 2 inches, preferably between about 0.5 inch and 1.5 inches, and more preferably about 0.75 inch. Changing the size of gear belt pulleys enables the degree of prestretch to change from about 50% to about 300%. 
         [0034]    Turning back to  FIG. 1 , machine  100  may also include a film clamp  150  for holding film  142  upon the start of boom arm  120  (shown in  FIG. 5 ). Clamp  150  enables machine  100  to operate automatically such that no operator intervention is required to adhere film  142  to load or to prestretch film  142  upon start of machine  100 . Without clamp  150 , an operator would need to manually attach film  142  to the load prior to starting machine  100 . 
       Sensing Mechanism 
       [0035]    Referring to  FIGS. 6 ,  7 ,  8 , and  9 , machine  100  may further include at least one sensing mechanism  182  designed to sense the presence of a load to start machine  100 . Sensing mechanism  182  may be an electric or electronic photo eye, a load sensor, a scale, an accelerometer or any other apparatus that may detect the existence of a load in the wrapping zone. In the embodiment shown in at least  FIG. 6 , sensing mechanism  182  is a photo eye that emits an infrared beam of light and contains a sensor to detect the reflection of the beam to determine if a load is present. Sensing mechanism  182  is further designed to sense the height and/or the top of the load to prevent carriage  140  from continuing to wrap above the load. If sensing mechanism  182  is a photo eye, the type of photo eye used with machine  100  may vary depending on various factors such as the environment of machine  100 , how much light is around machine  100 , and the color and/or reflectivity of the load. 
         [0036]    In one embodiment, sensing mechanism  182  may include a first photo eye (not shown) and a second photo eye (not shown). In this embodiment, the first photo eye would be configured to detect the presence of a load, and the second photo eye would detect the height of the load. 
         [0037]    Sensing mechanism  182  may mechanically detect the presence and height of a load. Preferably, however, sensing mechanism  182  may operate electrically, which may result in more accurate results and a longer life cycle for sensing mechanism and may allow for easier operation of machine  100  by routing a signal from sensing mechanism  182  to a single control box that also controls the wrapping functions of machine  100 . 
         [0038]    In one embodiment, sensing mechanism  182  may be coupled to prestretch carriage  140 , preferably proximate the top of carriage  140 . For example, sensing mechanism  182  may be coupled to carriage cover  139  and/or coupled to carriage top plate  148 . 
         [0039]    In another embodiment, sensing mechanism  182  may be coupled to a sensing mechanism mounting apparatus  180  configured to couple to prestretch carriage  140 . Apparatus  180  may include at least one sensing mechanism housing  183 , at least one strut  184 , at least one plate  186  configured to couple between strut  184  and machine  100 , at least one flange  188  configured to mount sensing mechanism  182  and sensing mechanism housing  183  to strut  184  wherein flange  188  may be moved along strut  184 . In one embodiment, at least one plate  186  is configured to couple to carriage cover  139 . In one embodiment, apparatus  180  is used when prestretch carriage  140  is approximately 30″ tall and the load is less than approximately 30″ tall. Further, in one embodiment, sensing mechanism  182  is a photo eye designed to detect dark and shiny loads. 
         [0040]    Sensing mechanism  182  may be electrically coupled to a control box. Control box may receive a command signal from a user to begin a wrapping process. Before executing that process, control box may acquire or receive one or more signals from sensing mechanism that verify that a load has been placed within the wrapping area and that determine the height of that load. 
       Plurality of Machines 
       [0041]    As discussed above, and shown in  FIG. 1 , system  10  comprises a plurality of machines. Preferably, machines  100 ,  200  and/or  300  have substantially similar components and/or processes of operation. However, machines may be both structurally and operationally distinct, provided that each machine  100 ,  200  and/or  300  wraps a load placed in front of it and has a sensing mechanism  182 ,  282  and  382  to determine the presence and/or height of the load. Machines  100 ,  200  and/or  300  may be electrically coupled to one another to facilitate decreasing the time to wrap multiple loads to increase the efficiency of system  10 . 
         [0042]    Each machine  100 ,  200 , and  300  includes at least one sensing mechanism,  182 ,  282 ,  382 . In the embodiment shown in  FIG. 1 , machine  200  includes at least one sensing mechanism  282  that is substantially similar to sensing mechanism  182 , and machine  300  includes at least one sensing mechanism  382  that is substantially similar to sensing mechanism  182 . In this embodiment, sensing mechanisms  182 ,  282  and  382  are photo eyes, and each is designed to emit an infrared beam of light to sense the presence of a load to start machines  100 ,  200  and/or  300  and is further designed to sense the height of each load placed in front of machines  100 ,  200 , and/or  300  to be wrapped. 
         [0043]    System  10  further includes at least one master control box  400  that is in electric or electronic communication with at least one sensing mechanism  182 ,  282  and/or  382 . At least one conduit  402  is coupled between sensing mechanism  182  and control box  400 , at least one conduit  404  is coupled between sensing mechanism  282  and control box  400 , and at least one conduit  406  is coupled between sensing mechanism  382  and control box  400 . In one embodiment, system  10  may include a wireless communication and/or signal to facilitate communication between sensing mechanisms  182 ,  282 , and/or  382  and control box  400  rather than conduits. In a further embodiment, communication between sensing mechanisms  182 ,  282 , and/or  382  and control box  400  may include infrared or radio frequency signals to facilitate communication. 
         [0044]    As shown in  FIG. 9 , sensing mechanisms  182 ,  282  and  382  may be electrically coupled to each other and to control box  400 . In one embodiment, sensing mechanisms may be connected serially so that operation of system  10  is dependent on loads  500 ,  502 ,  504  being present in front of each of machines  100 ,  200  and  300 . Preferably, however, sensing mechanisms  182 ,  282 ,  382  are connected in parallel so that machines  100 ,  200  and  300  may operate independently. For example, the presence of loads  500 ,  502  in front of machines  100  and  200 , respectively, will cause loads  500 ,  502  to be wrapped while the presence of no load in front of machine  300  will cause machine  300  to take no action. 
         [0045]    Master control box  400  further may include at least one start button  401  such that when start button  401  is triggered, master control box  400  may start each machine  100 ,  200  and/or  300  depending on the signal or signals received from each sensing mechanism  182 ,  282  and/or  382 . In one embodiment, master control box  400  may not include start button  401 , but rather a separate control box  403  electrically coupled to master control box  400  via a conduit  405  may include start button  401 . 
         [0046]    Additionally, master control box  400  may have a touch screen (not shown) enabling a user to touch the screen to operate and control various functions of system  10  through master control box  400 . 
         [0047]    As shown in  FIG. 8 , system  10  may further include individual control boxes  420 ,  422  and/or  424  for each machine  100 ,  200  and/or  300 , respectively, alternatively or in addition to master control box  400 . Each control box  420 ,  422  and/or  424  may include a start button (not shown). Each control box  420 ,  422  and/or  424  may be in electronic communication with each respective sensing mechanism  182 ,  282  and/or  382  via conduits  408 ,  410  and/or  412 , respectively. Further, each control box  420 ,  422  and/or  424  may be in electronic communication with master control box  400  such that each control box  420 ,  422  and/or  424  operate in conjunction with one another. 
       Method of Operation 
       [0048]    During operation, a forklift operator may drop at least one load on a pallet in front of at least one machine  100 ,  200 , and/or  300  so that the load can be wrapped in film  142 . For example, the forklift operator may drop at least one of three loads  500 ,  502 , and/or  504  in front of machines  100 ,  200 , and/or  300  such that each load may be wrapped. In one embodiment, the forklift operator may drop at least one of three loads  500 ,  502 , and/or  504  from a forklift, a single pallet jack, a double pallet jack, a triple pallet jack, a quadruple pallet jack, and/or another suitable machine that enables a forklift driver to transport loads and/or pallets. A single pallet jack may enable a forklift operator to carry a single load, and a double, triple, and/or quadruple pallet jack may enable a forklift driver to carry or transport more than one load at a time. At the present time, a forklift operator can carry a maximum of three loads with each load having a width and a length of no more than about 15′. Each load  500 ,  502 , and/or  504  may be of varying sizes. If the forklift operator is transporting more than one load at a time, the operator may not drop each load consecutively. Specifically, forklift operator may drop first load  500  in front of machine  100 , forklift operator may drop second load  502  in front of machine  200 , and forklift operator may drop third load  504  in front of machine  300 , leaving space between each of the loads, and the forklift operator then drives from machine  300  to at least one of the master control box  400  and/or control box  403 . 
         [0049]    Forklift operator may then start system  10  by pressing start button  401  to start at least one of machines  100 ,  200  and/or  300 . Specifically, in one embodiment, the fork lift operator presses start button  401  on separate control box  403  that transmits a signal  414  to master control box  400  via a conduit  405 . Master control box  400  then receives signal  414  and transmits at least one signal  416  to machines  100 ,  200  and/or  300  via each respective conduit  402 ,  404  and/or  406 . Alternatively, forklift operator may start system  10  by pressing a separate start button (not shown) on each separate machine  100 ,  200 , and/or  300  to start each respective machine. 
         [0050]    Once machines  100 ,  200  and/or  300 , specifically sensing mechanisms  182 ,  282  and/or  382 , receive signal  416 , each sensing mechanism  182 ,  282  and/or  382  determines whether a load is present. In the case where sensing mechanisms  182 ,  282  and  382  are photo eyes, sensing mechanisms  182 ,  282  and  382  each emit an infrared beam of light  418  towards the front  114  of each machine  100 ,  200 ,  300  to sense whether a load is present. If beam of light  418  refracts back to sensing mechanisms  182 ,  282  and/or  382 , or depending on the time it takes for beam of light  418  to refract, sensing mechanisms  182 ,  282 ,  382  may determine that a load is present. Each sensing mechanism  182 ,  282  and/or  382  that received a refracted signal may then transmit a start signal  430  to start each respective machine  100 ,  200 , and/or  300 . If beam of light  418  is not refracted back to sensing mechanisms  182 ,  282  and/or  382 , or if the light&#39;s refraction time signifies that no load is present, then machine  100 ,  200  and/or  300  assumes that a load is not present and does not need to be wrapped and sensing mechanisms  182 ,  282 ,  382  either send a signal to machines  100 ,  200 ,  300  to take no further action or just send no signal to machines  100 ,  200 ,  300  to take any action. 
         [0051]    When each respective machine  100 ,  200  and/or  300  receives start signal  430 , each modular arm  164  begins to rotate, preferably in a clockwise direction  432 , such that modular arm  164 , boom arm  120 , and carriage  140  rotate around the load. Upper portion  162  of top frame  160  remains stationary and ring gear  167  rotates modular arm  164  in clockwise direction  432 . As modular arm  164  begins to rotate, each sensing mechanism  182 ,  282  and/or  382  emits an infrared beam of light  434  towards load  500 ,  502 , and/or  504  respectively to determine the height of each load and to determine where carriage  140  should stop moving upward. Specifically, load height is sensed while load  500 ,  502 , and/or  504  is being wrapped. The load height of each load  500 ,  502 , and/or  504  may be different. When sensing mechanisms  182 ,  282 , and/or  382  senses that it is over (or above) respective load  500 ,  502 , and/or  504 , carriage  140  travel in the upward direction is stopped to prevent wrapping above the height of the load. 
         [0052]    Sensing mechanisms  182 ,  282 ,  382  may further be used to calculate the height and/or weight of each load  500 ,  502 ,  504  being wrapped. System  10  may transmit this information from sensing mechanisms  182 ,  282 ,  382  to one or more of control boxes  400 ,  403  or otherwise display it to an operator to provide the operator with information about the loads  500 ,  502 ,  504  being wrapped. 
         [0053]    Clamp  150  holds film  142  against the load such that film  142  does not need to be manually attached to the load prior to starting machine  100 . Stretch film  142  passes through carriage  140  threading past at least two rubber rollers, primary roller  144  and secondary roller  146 , to stretch film  142  prior to applying film  142  to the load. Secondary roller  146  has a rotational speed geared faster than primary roller  144  such that secondary roller  146  pulls film  142  from primary roller  144  stretching film  142  between rollers  144  and  146 . For example, prestretch carriage  140  may stretch approximately 10″ of film  142  into approximately 40″ of prestretch film  142 . Stretching film  142  prior to applying film  142  to the load decreases the amount of film  142  necessary to wrap the load and also activates the film memory effect causing film  142  to want to stretch back to its original length after it is applied to the load, thereby film  142  tightens on the load and holds the load securely. 
         [0054]    Prestretch carriage  140  applies a spiraling layer of prestretched film  142  to the load encapsulating the load in film  142 . In one embodiment, the spiraling layer starts at the load bottom  508 . Specifically, as the load is wrapped, carriage  140  moves along boom arm  120  between boom arm top  124  and boom arm bottom  126  to apply film  142  to the load. Preferably, carriage  140  applies film  142  from bottom  508  to load top  506 . Further, as carriage  140  wraps the load with film  142 , the guides of bracket  128  enable carriage  140  to move along boom arm  120  in a substantially straight manner. 
         [0055]    As the load is wrapped, the sensor on carriage  140  may read the distance between the cam and the sensor. As the cam moves further from the sensor, the prestretch carriage motor turns faster and feeds film  142  faster and the dancer bar assembly  151  feeds film  142  at corners of the load to prevent film  142  from tearing. While the load is being wrapped, carriage door  190  pushes film  142  against rollers  144  and  146  to maintain contact between film  142  and rollers  144  and  146  and further to maintain prestretch consistency. 
         [0056]    Once load is substantially wrapped and carriage  140  is proximate bottom  508  of the load, stretch film wipe system  110  sweeps across film  142  to eliminate film tails. Specifically, arm  114  of system  110  extends out after the wrap cycle is completed, heat impulse wire  116  turns on momentarily to cut film  142 , and wiper  118  extends out to wipe film on the load. 
         [0057]    Further, safety photo eye  130  operates continuously or intermittently to ensure that nothing has interrupted the path between the reflector  136  and photo eye  130  to avoid objects being wrapped between film  142  and load. If something interrupts the path between photo eye  130  and reflector  136 , the infrared beam of light will not be reflected by reflector  136 , and photo eye  130  will transmit a signal stop the operation of machine  100 . 
         [0058]    While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific exemplary embodiment and method herein. The invention should therefore not be limited by the above described embodiment and method, but by all embodiments and methods within the scope and spirit of the invention as claimed.