STRAPPING TRACK ASSEMBLY AND METHODS OF USING THE SAME

Abstract

The present description discusses apparatuses and methods for applying straps around a bundle of objects. The apparatus includes a track assembly extending substantially about a strapping station. The track assembly is adapted to receive a strap and to release the strap during a tensioning operation. Strap can be fed through the track assembly without damaging the strap.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/921,022 filed Mar. 30, 2007, which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to strapping apparatuses and methods for applying straps around bundles of objects. More particularly, the invention relates to strapping track assemblies for strapping apparatuses and methods of using the same.

2. Description of the Related Art

Strapping machines for applying flexible straps around bundles of objects have been developed in recent years and are disclosed in U.S. Pat. No. 5,560,180; U.S. Pat. No. 6,363,689; and U.S. Patent Application Publication No. 2002/0116900 A1. A conveyor often conveys a bundle of objects to a strapping station where straps are automatically applied before the conveyor moves the strapped bundle away from the strapping station.

FIG. 1 is a front isometric view of a conventional strapping machine 10. The strapping machine 10 has several major assemblies, including a feed and tension assembly 15, an accumulator 14, a strap dispenser 30, a sealing assembly 40, a track assembly 50, and a control system 60 having an operator interface region 65. The strapping machine 10 may also include a frame 70 that structurally supports and/or encloses the major subassemblies. The assembly and purposes of the conventional major assemblies are described in detail in U.S. Pat. No. 6,363,689.

During operation, a strap is moved through the track assembly 50 in the direction indicated by the arrows 20 before applying the strap to the bundle. Unfortunately, the track assembly 50 includes features, such as exposed edges of strap guides, which interfere with the advancement of the strap. For example, an end of the strap can catch on any one of the exposed leading edges of the strap guides during a feed sequence. This may cause the strap to become damaged or stuck and may require user intervention to continue the feed sequence. Misfeeds occur when the end of the strap unintentionally passes through gaps along the track assembly 50. The section of the strap that escapes from the track assembly 50 is snaked back into the track assembly 50 so that the strap can be further advanced through the track assembly 50. Once the strap is fed through the track assembly 50, the strap can be drawn from the track assembly 50 about the bundle adjacent to the sealing assembly 40.

BRIEF SUMMARY

Apparatuses disclosed herein can be used to apply one or more straps around a bundle of objects. A variable or constant force can be applied to tension the strap about the bundle of objects while the strap is sealed around the bundle of objects. The apparatus may include a strapping track assembly extending about a strapping station. The track assembly is adapted to receive a strap during a feed sequence and to release the strap during a tensioning sequence. The track assembly, in some embodiments, is adapted to reduce or prevent the occurrence of misfeeds, such as misfeeds attributable to the end of the strap escaping through gaps next to an intended strap path within the track assembly. This ensures that the strap is properly routed through the track assembly.

In some embodiments, a strapping apparatus for bundling objects comprises a strapping station and a track assembly. The track assembly is adapted to receive a strap and to bundle objects at a strapping station using the strap. The track assembly, in some embodiments, comprises a stationary frame, a first strap guide, a second strap guide, and a corner strap guide interposed between the first and second strap guides. The stationary frame can keep its configuration during operation. The first and second strap guides can be linear strap guides that extend along a substantially straight axis. A strap path may be defined between the first strap guide and the frame, the second guide and the frame, and the corner strap guide and the frame. The strap path can have a generally rectangular shape, elliptical shape, or any other suitable shape. In some embodiments, the strap path is a closed loop path.

The corner strap guide can include a leading end and a trailing end. A trailing end of the first strap guide can be positioned between the leading end of the corner strap guide and a first adjacent section of the strap path. The trailing end of the corner strap guide can be between a leading end of the second strap guide and a second adjacent section of the strap path. As such, the strap can slide along the first strap guide, corner strap guide, and second strap guide without striking the upstream end or edges of the strap guides.

The strap guides can be received by one another. In some embodiments, the trailing end of the first strap guide extends into the corner strap guide. The trailing end of the corner strap guide extends into the second strap guide. The trailing ends may keep the strap away from the leading edges of the downstream strap guides.

In some embodiments, at least one of the first strap guide, the second strap guide, and the corner strap guide tapers inwardly (e.g., towards the strap path) in the downstream direction. The tapered strap guides can position (e.g., center) the strap with respect to downstream strap guides.

Biasing mechanisms can move the strap guides from open positions to closed positions. In some embodiments, a plurality of biasing mechanisms can cooperate to push the strap guides against the frame. The biasing mechanisms can include one or more springs that cooperate to apply desired forces to the strap guides. If sufficient forces are applied to the strap, the biasing mechanisms can allow the strap guides to open.

In other embodiments, a track assembly for receiving a strap and bundling objects at a strapping station using the strap is provided. The track assembly comprises an outer frame and a plurality of strap guides. The plurality of strap guides is coupled to the outer frame so as to define a strap path. In some embodiments, the strap guides are mounted to the inner periphery of the frame. The strap path, in some embodiments, can extend along the length of the track assembly. Each strap guide has a trailing end that is disposed between the strap path and a leading edge of one of the downstream strap guides.

The plurality of strap guides can include a first corner strap guide that defines a first curved section of the strap path, a second corner strap guide that defines a second curved section of the strap path, and an elongate strap guide (e.g., a linear strap guide or an array of linear strap guides) extending between the first and second corner strap guides. The elongate strap guide can define a substantially linear section of the strap path. If the outer frame has a substantially rectangular shape, the elongate strap guide can extend along one side of the frame. In some embodiments, the elongate strap guide is a longitudinally-extending, U-shaped member.

At least one of the strap guides can taper inwardly towards the strap path. In some embodiments, all or most of the strap guides taper inwardly towards the strap path in the downstream direction. Each of the strap guides can extend partially through an adjacent pair of the strap guides.

In some embodiments, the strap guides may include respective strap retainers. The strap retainers together may extend along nearly all of the longitudinal length of the strap path such that a strap moving along the strap path is captured between the strap retainers and the outer frame. The strap retainers can cooperate to define a substantially continuous surface along substantially the entire strap path, if needed or desired.

In some embodiments, a strap guide can have a narrowed leading end with respect to a strap path and a widened trailing end with respect to the strap path. In some embodiments, for example, a distance between opposing sides at the leading end can be less than a distance between the opposing sides at the trailing end.

In some embodiments, a method for passing a strap through a track assembly is provided. The method comprises moving an end of a strap along a strap path. The path is positioned between a plurality of interconnected strap guides and an outer frame.

In some embodiments, each strap guide has a trailing end that is disposed between the strap path and a leading edge of one of the downstream strap guides such that the end of the strap is spaced from the leading end of the downstream strap guide. In some embodiments, the strap guides are interleaved and surround the inner periphery of the frame.

In some embodiments, the end of the strap is passed out of downstream ends of the strap guides disposed within corresponding downstream strap guides. The strap is subsequently used to bundle objects located at a strapping station after moving the end of the strap through the track assembly. The strap can be tensioned to move the strap guides from a first position (e.g., a closed position) for retaining the strap to a second position (e.g., an open position, spread apart configuration, etc.) to allow removal of the strap.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. The shapes of various elements and angles may not be drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility.

FIG. 1 is an isometric view of a conventional strapping machine.

FIG. 2 is a front, top view of a strapping apparatus, in accordance with one embodiment.

FIG. 3 is a front, top view of a strapping track assembly, in accordance with one embodiment.

FIG. 4 is a front, top view of a strapping track assembly with guard panels shown removed, in accordance with one embodiment.

FIG. 5 is an isometric view of a portion of the strapping track assembly of FIG. 4, in accordance with one embodiment.

FIG. 6A is an enlarged pictorial view of a portion of a strapping track assembly, in accordance with one embodiment.

FIG. 6B is a side elevational view of the interface between two guide members, in accordance with one embodiment.

FIG. 7 is a cross-sectional view of the strapping track assembly of FIG. 5 taken along line 7-7.

FIG. 8 is a pictorial view of a strap guide member, in accordance with one embodiment.

FIG. 9 is a front elevational view of the strap guide member of FIG. 8.

FIG. 10 is a back elevational view of the strap guide member of FIG. 8.

FIG. 11 is a top plan view of the strap guide member of FIG. 8.

FIGS. 12 and 13 are side elevational views of the strap guide member of FIG. 8.

FIGS. 14 and 15 are pictorial views of a strap guide member of a corner strap guide, in accordance with one embodiment.

FIG. 16 is a front elevational view of a strap guide member of a corner strap guide, in accordance with one embodiment.

FIG. 17 is a side elevational view of a strap guide member of a corner strap guide, in accordance with one embodiment.

FIG. 18 is an isometric view of a frame of a strapping track assembly, in accordance with one embodiment.

FIG. 19 is a front elevational view of the frame of FIG. 18.

FIG. 20 is a front elevational view of a control system, in accordance with one embodiment.

FIG. 21 is a side view of operator controls of the control system of FIG. 20.

DETAILED DESCRIPTION

The present disclosure is directed to, among other things, strapping apparatuses, components and subassemblies of strapping apparatuses (e.g., strapping track assemblies), and methods for strapping bundles of objects. Specific details of certain embodiments are set forth in the following description, and in FIGS. 2-21, to provide a thorough understanding of such embodiments. A person of ordinary skill in the art, however, will understand that the disclosed embodiments may have additional components and features, and that the embodiments may be practiced without several of the details described in the following description.

Throughout the following discussion and in the accompanying figures, the strap material is shown and referred to as a particular type of material, namely, a flat, two-sided, tape-shaped strip of material solely for the purpose of simplifying the description of various embodiments. It should be understood, however, that several of the methods and embodiments disclosed herein may be equally applicable to various types of strap material, and not just to the flat, two-sided, tape-shaped material shown in the figures. Thus, as used herein, the terms “strap” and “strap material” should be understood to include, without limitation, all types of materials used to bundle objects, for example, synthetic materials, natural materials, metallic materials, or some other more rigid strap material. One type of strap that may be used with all or some of the embodiments described herein is a paper cord-type strap comprised of individual round cords laterally bonded together to form a continuous strap. The strap may be rigid, semi-flexible, or flexible depending on the application.

FIG. 2 illustrates a strapping apparatus 100 that includes a plurality of conveyors 110 for moving bundles into and out of a strapping station 120, which is surrounded by a strapping track assembly 118. Various types of strapping stations can be employed based on the dimensions of the bundles to be strapped. Different types of components (e.g., tensioning units, sealing head assemblies, etc.) can be located at or proximate to the strapping station 120. Strap employed during bundling operations is fed about the strapping track assembly 118 in a strap-feed direction 119, illustrated in the counter-clockwise direction, along a strap path (e.g., a substantially rectangular or elliptical strap path) within the strapping track assembly 118. A frame 139 for supporting the strapping apparatus 100 can be temporary or permanently affixed to the floor. The independently powered conveyors 110 are independently supported by conveyor frames 145.

Some of the other major assemblies of the strapping apparatus 100 include, without limitation, a control system for programming and controlling various functions of the apparatus, an accumulator 96, and a feed and tension unit for receiving and feeding the strap around one or more bundles on the conveyors 110. The strapping apparatus 100 can be further configured with a sealing head assembly 98 for sealing the strap around the bundle (not shown). At least some of the major assemblies can be of modular construction, which allows them to be used in multiple frame configurations or attached as add-on components to existing strapping machines. The illustrated strapping track assembly 118 has a modular construction for use with a wide range of strapping machines. Various assemblies and components of the strapping apparatus 100 are discussed in detail below.

FIG. 3 shows the strapping track assembly 118 partially enclosed by spaced apart guard panels 140a, 140b (collectively 140) and opposing spaced apart guard panels 142a, 142b (collectively 142). Each of the guard panels 140, 142 has cutouts 150, 152 that provide access to components of the strapping track assembly 118. In some embodiments, the guard panels 140, 142 can be easily removed to perform maintenance on the track assembly 118. A handle 153 may be used to move the entire strapping apparatus 100, the track assembly 118 with respect to the frame 139, and the like

Referring to FIG. 4, the strapping track assembly 118 (shown with the guard panels 140, 142 removed) may provide the reliability of a fully enclosed track configuration while reducing, limiting, or substantially eliminating problems associated with misfeeds, straps catching on edges (e.g., leading edges) of strap guides, and the like. The illustrated strapping track assembly 118 includes five linear track sections 201a-e (collectively 201) and four corner sections 202a-d (collectively 202). Each of the corner sections 202 is interposed between one pair of the linear track sections 201 and can be similar to one another.

A plurality of strap guides 220a-e, 222a-d is coupled to a rigid frame 240 to define a strap path of travel. The strap guides 220a-e (collectively 220) are elongate strap guides (illustrated as substantially linear guides) at corresponding track sections 201a-e, and the strap guides 222a-d (collectively 222) are corner strap guides at corresponding corner sections 202a-d. The strap guides 220, 222 are interleaved in the feed direction such that the leading edges of the strap guides 220, 222 do not contact the strap so as to reduce, limit, or substantially eliminate the occurrence of misfeeds, damage to the strap attributable to the leading edges, and the like. Each of the strap guides 220, 222 can have a trailing end (e.g., a downstream end) that keeps the strap from contacting a leading end (e.g., an upstream end) of one of the adjacent downstream strap guides, as discussed in detail below.

As shown in FIG. 5, the corner strap guide 222d is interposed between the strap guides 220d, 220e. A central section 225 of the corner strap guide 222d extends from the upstream strap guide 220d to the downstream strap guide 220e. In the illustrated embodiment, a substantial portion of the corner strap guide 222d extends between the adjacent strap guides 220d, 220e.

The corner strap guide 222d includes a leading end 260 for surrounding the upstream strap guide 220d and a trailing end 262 for extending into the downstream strap guide 220e. A trailing end 270 of the upstream strap guide 220d is between the leading end 260 of the strap guide 222d and a strap path (discussed in connection with FIGS. 6A, 6B, and 7), and the trailing end 262 of the corner guide 222d is between a leading end 272 of the downstream strap guide 220e and the strap path. The trailing ends 270, 262 thus physically separate and protect the strap from the respective leading edges 261, 273. This ensures that the edges 261, 273 do not cause misfeeds.

Each of the strap guides 220d, 220e, 222d can taper with respect to the strap path, for example, in the downstream direction. In some embodiments, including the illustrated embodiment of FIG. 5, the narrowed trailing end 270 of the strap guide 220d extends into the widened leading end 260 of the corner strap guide 222d, and the narrowed trailing end 262 of the corner strap guide 222d extends into the widened leading end 272 of the strap guide 220e. The narrowed trailing ends 270, 262 can closely surround and help center the strap with respect to the downstream strap guides 222d, 220e, respectively.

Referring to FIG. 6A, a transverse width W of the leading end 260 is greater than a length L of the portion of the trailing end 270 within the strap guide 222d. The length L can be measured in the direction of a strap path 302 aligned with a longitudinal gap 303 extending along the inner periphery of the track assembly 118. The leading end 260 can closely surround the trailing end 270 while allowing slight relative movement between the strap guides 220d, 222d. The length L of the portion of the leading end 270 within the strap guide 222d can be selected based on, for example, the desired amount of guide overlap, flexibility of the strap, and ease of assembly. As such, the end of the strap can move along the strap path 302 past the intersection of the strap guides 220d, 222d (see FIG. 6B) without the strap end passing through any gaps between the strap guides 220d, 222d. In this manner, strap misfeeds can be avoided.

As used herein, the term “strap guide” can include, but is not limited to, one or more components adapted to engage and guide a strap along a desired strap path. A strap may slide smoothly between strap guides positioned along a strap path without damaging the strap. In some embodiments, a strap guide can be a monolithically formed one-piece component. In other embodiments, a strap guide can include a plurality of separate components. For example, the strap guide 220e of FIGS. 6A, 6B, and 7 includes a pair of spaced apart strap guide members 236a, 236b movable between a closed position 237 and an open position 238 (shown in phantom). Each of the strap guide members 236a, 236b includes a respective sidewall 239a, 239b and a respective strap retainer 243a, 243b. The illustrated sidewall 239a is approximately parallel to the sidewall 239b when the strap guide 220e is closed.

FIGS. 8-13 show the strap guide member 236a that includes the retainer 243a extending substantially perpendicularly from the sidewall 239a. The retainer 243a includes a lower engagement surface 247 for slidably contacting the strap. The sidewall 239a includes a plurality of openings 250 (FIG. 8) through which elongate rods 251 (FIG. 5) or biasing mechanisms 203a, 203b can extend. The openings 250 can be holes, slots, and the like.

As shown in FIGS. 14-17, a strap guide member 238a of the strap guide 222d includes a sidewall 273 and an arcuate strap retainer 277. The strap retainer 277 includes an engagement surface 279 for slidably contacting the strap. Because the strap guide 220d is substantially perpendicular to the strap guide 220e (see FIG. 4), the strap retainer 277 subtends an angle of about 90 degrees such that the tensioned strap can curve along the strap retainer 277 between the strap guides 220d, 220e. Other configurations and curvatures of the strap retainer 277 are also possible.

With reference again to FIG. 5, biasing mechanisms 203a, 203b can bias the strap guide members 236a, 236b to the illustrated closed position. The biasing mechanisms 203a, 203b can be generally similar to each other. The biasing mechanism 203a includes a spring retainer 241 and a biasing member 239 captured between the spring retainer 241 and the guide member 236a. The spring retainer 241 can be a free floating cap screw extending outwardly from both sides of the track assembly 118. The biasing members 239 can be interposed between the guide members 236a, 236b and the caps of the spring retainer 241. In some embodiments, the retainer 241 is a floating cap screw and an associated hex nut are centered about the track 118 by two compression biasing members 239 in the form of compression springs applying somewhat equal forces. This has the effect of providing an equal load on both sides of the strap as the strap is pulled from the track assembly 118. In other embodiments, the stop 241 is fixedly coupled to the frame 240 such that the biasing member 239 presses the strap guide member 236a against the frame 240. The biasing member 239 can be in the form of one or more springs (e.g., helical springs, coil springs, etc.), elastically compressible members, and the like. Other types of biasing members can also be used.

Referring to FIGS. 5 and 7, the biasing mechanisms 203a, 203b may hold the strap guide 220e proximate to or against the outer frame 240 so as to form a partially or fully enclosed channel 300. The strap path 302 (shown in phantom line in FIGS. 6A and 7) extends longitudinally along the open channel 300. A strap 304, shown in phantom line in FIG. 7, can move along the strap path 302 through the track assembly 100. The edges of the strap 304 can slide along the strap retainers 243a, 234b. As such, the strap path 302 can be defined, at least in part, by the strap guides 220, 222 and the frame 240, as well as other components suitable for contacting the strap.

With reference to FIGS. 6A, 6B, and 7, the strap retainers 243a, 243b are spaced from an engagement surface 283 of the frame 240. The strap 304 can be captured between lower surfaces of the strap retainers 243a, 243b and the surface 283. The illustrated strap 304 is spaced from the engagement surface 283.

Each of the plurality of strap guides 220, 222 can include one or more strap retainers that extend along nearly all of their respective lengths. The strap retainers can extend along nearly all, or all, of the length of the strap path 302. In some embodiments, the strap retainers collectively extend along at least 95%, 90%, or 80% of the length of the strap path 302 defined by the strapping strap assemble 118. Such embodiments ensure that the strap is properly guided along a substantial portion of the strap path 302.

With respect to FIGS. 18 and 19, the frame 240 includes a plurality interlocked elongate frame sections 301a-e (collectively 301) and corner frame sections 302a-d (collectively 302). The assembled track sections 201 are formed by the respective frame sections 301 and strap guides 220 movable with respect to the frame sections 301. The corner track sections 202 are formed by the respective corner frame sections 302 and the strap guides 222 movable with respect to the corner frame sections 302. In other embodiments, the frame 240 can have a one-piece construction. Such embodiments may be more rigid than the multi-piece frame 240 illustrated in FIGS. 18 and 19.

Various types of production cycles can be performed using the strapping track assembly 118. During the tensioning cycle, a sealing head assembly 98 grips the free end of the strap and a feed/tension unit begins to tension the strap around the product surrounded by the strapping track assembly 118. As the strap is drawn back by the feed/tension unit, the forces may overcome the bias of the biasing mechanisms 203a,b to cause the closed strap guides 220, 222 to move (e.g., pivot) to the open positions, thereby allowing the strap to escape from the separated strap guides 220, 222. As the strap forces the track sections 220, 222 open, each successive set of strap guides 220, 222 are urged open by the previous set of strap guides, thereby providing a controlled release of the strap. The amount of overlap between the strap guides 220, 222 can be selected such that the strap guides open together. During the tensioning cycle, the interleaved track design also has the advantage of having few or no gaps between strap guides to catch the strap edges and to reduce the occurrence of the strap escaping from the track assembly 118.

The strapping apparatus 100 can be controlled by a control system 800 illustrated in FIG. 20. The control system 800 can be mounted or incorporated into the accumulator 96 and may include a programmable logic controller (PLC) 802 which operates in conjunction with various input and output devices and controls the major subassemblies of the strapping apparatus 100. Input devices may include, for example, momentary and maintained push buttons, selector switches, toggle switches, limit switches, photoelectric sensors, and inductive proximity sensors. Output devices may include, for example, solid state and general purpose relays, solenoids, and indicator lights. Input devices are scanned by the controller 802, and their on/off states are updated in a controller program. The controller 802 executes the controller program and updates the status of the output devices accordingly. Other control functions of the controller 802 are described below in further detail.

In some embodiments, the programmable controller 802 and its associated input and output devices may be powered using a 24 VDC power supply. The controller 802, power supply, relays, and fuses may be contained within a control panel, as illustrated in FIG. 21. The momentary and maintained push buttons, selector switches, and toggle switches 810 may be located on the control panel. The limit switches, inductive proximity sensors, photoelectric sensors, and solenoids are typically located within the strapping apparatus 100 at their point of use. An indicator light stack may be mounted on the top of the arch indicating a strap mis-feed, out-of-strap, normal running or machine malfunction condition, for example.

One commercially-available PLC 802 suitable for use with the strapping apparatus 100 is the MICROLOGIX 1500 manufactured by Allen-Bradley/Rockwell. This device includes PNP digital and relay type outputs. In addition the PLC utilizes input and output cards to interface to external production line equipment control system and to four machine mounted motors (e.g., Dunkermotoren BG75 servomotors) which drive the accumulator 96, feed and primary tension, secondary tension and sealing head functions. One skilled in the art will understand that another industry standard PLC may also be used in place of the PLC described above.

The MICROLOGIX 1500 PLC 802 has communication ports, including an RS232C port for program uploads, downloads and monitoring and a RS232C port for connection to an EZ-AUTOMATION HMI (Human-Machine-Interface) 812 mounted to the control panel side. The HMI provides machine diagnostics and operational data (e.g., number of straps applied, sensor status, etc.) in addition to providing operational parameter selections (e.g., strap position on the bundle, number of straps per bundle, etc.).

The operation of the strapping apparatus 100 may involves pulling strap from a dispenser and feeding a free end of the strap through the accumulator 96, through the feed and tension unit, up through the sealing head assembly 98, and then around the strapping track assembly 118. U.S. application Ser. No. 12/072,107 discloses these components and their functionality. Because the track assembly 118 is adapted to minimize or limit the occurrence of misfeeds and/or damage to the end of the strap due to unwanted large gaps between strap guides, strap can be consistently fed through the track assembly 118. After the strap is fed around the strapping track assembly 118, the free end is guided back into the sealing head assembly 98. At this point, the strap is in position to start a strapping cycle where the strap can be tensioned and secured about a bundle of objects.

In operation, during a tensioning or bundling operation, the tensioning of the strap occurs in two stages, a primary tension stage and a secondary tension stage. In the primary tensioning stage, the strap is pulled out of the track assembly 118 and, in some processes, down onto the bundle of objects. The secondary tensioning sequence involves binding the strap tightly around the bundle of objects located in the strapping station 120. After the strap is tensioned to the point that a servomotor stalls, a controller permits a predetermined amount of time to pass so as to allow the sealing head assembly 98 to rotate to grip the strap. After securing the strap, the tension is released just prior to cutting the strap from the supply to prevent the strap from fraying. The strap is then cut and sealed. Once the sealing operation is complete, the feeding sequence may then be repeated.

The primary tensioning sequence provides enough force on the strap to pull the strap inwardly away from the frame 240 and through the longitudinal openings 303 provided by the strap guides 220, 222. As the strap is tensioned around the bundle of objects, the straight and corner track guides 220, 222 can be opened by the strap 102, allowing the strap to pull clear of the channel 300. The force applied to the strap can overcome the biasing of the biasing mechanisms for convenient opening of the strap guides 220, 222. The strapping track assembly 118 may be configured to permit controlled sequential strap removal from the strap guides 220, 222, thereby reducing, limiting, or substantially eliminating damage to the strap. After the strap clears the channel 300, the strap is pulled around a bundle of objects and both the straight and corner track guides 220, 222 close because of the biasing mechanisms.

Once the strap has been sufficiently tensioned around the bundle of objects, the non-free end of the strap can be cut and then both ends of the strap can be sealed together. The sealing operation commences when several sealing head cams in the sealing head assembly 98 begin to rotate, forcing a gripper to pinch the free end of the strap against an anvil. Those skilled in the art will recognize that the strapping apparatus 100 can be configured, depending on strap orientation, to accommodate the same gripper on the opposite side. After gripping the free end of the strap in the sealing head assembly 98, the feed and tension unit retracts the excess strap from the track assembly 118 (i.e., the tensioning operation discussed above).

In one embodiment, the strap used to bundle objects can have a heat-activated adhesive applied thereon. Preferably, the adhesive on the strap is applied to the strap during the manufacturing process of the strap. Heat is applied to the strap by inserting a heater blade between the two overlapping ends of the strap and lightly pressing the ends against the blade by raising a press platen. Various types of further processing can be performed on the strap to ensure that strap is properly secured. At this point, the strapping track assembly 118 is ready for the strap to be fed again.

Except as described herein, the embodiments, features, systems, devices, materials, methods and techniques described herein may, in some embodiments, be similar to any one or more of the embodiments, features, systems, devices, materials, straps, methods and techniques described in U.S. Patent Publication No. 2004/0200191, U.S. patent application Ser. No. 12/072,107, and U.S. Provisional Patent Application No. 60/921,022. In addition, the embodiments, features, systems, devices, materials, methods and techniques described herein may, in certain embodiments, be applied to or used in connection with any one or more of the embodiments, features, systems, devices, materials, methods and techniques disclosed in the above-mentioned U.S. Patent Publication No. 2004/0200191 and U.S. Provisional Patent Application No. 60/903,230. U.S. Patent Publication No. 2004/0200191, U.S. patent application Ser. No. 12/072,107, and U.S. Provisional Patent Application No. 60/921,022 are hereby incorporated by reference herein in their entireties.

Although specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. The teachings provided herein of the invention can be applied to other methods and apparatus for strapping bundles of objects, and not just to the methods and apparatus for strapping bundles of objects described above and shown in the figures. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification. Accordingly, the invention is not limited by the foregoing disclosure, but instead its scope is to be determined by the following claims.

Claims

1. A strapping apparatus for bundling objects, comprising:

a strapping station; and

a track assembly adapted to receive a strap and to bundle objects at the strapping station using the strap, the track assembly comprising a stationary frame, a first linear strap guide, a second linear strap guide, and a corner strap guide interposed between the first and second linear strap guides, a strap path defined between the frame and the first linear strap guide, the second linear strap guide, and the corner strap guide, a trailing end of the first linear strap guide extending downstream along the strap path past at least a portion of a leading end of the corner strap guide, a trailing end of the corner strap guide extending downstream past a portion of a leading end of the second linear strap guide.

2. The strapping apparatus of claim 1, wherein the trailing end of the first linear strap guide extends between the leading end of the corner strap guide and the strap path, the trailing end of the corner strap guide extends between the leading end of the second linear strap guide and the strap path.

3. The strapping apparatus of claim 1, wherein at least one of the first linear strap guide, the second linear strap guide, and the corner strap guide tapers inwardly towards the strap path in a down stream direction.

4. The strapping apparatus of claim 1, further comprising:

at least one biasing mechanism coupled to the frame, the at least one biasing mechanism moves one of the first linear strap guide, the second linear strap guide, and the corner strap guide from an open position for releasing a strap towards a closed position for capturing a strap.

5. The strapping apparatus of claim 1, wherein the trailing end of the first linear strap guide extends through the leading end of the corner strap guide.

6. A track assembly for receiving a strap and bundling objects at a strapping station using the strap, the track assembly comprising:

an outer frame; and

a plurality of strap guides for releasably retaining a strap, the plurality of strap guides coupled to the outer frame so as to define a strap path located between the plurality of strap guides and the frame, each strap guide having a trailing end disposed between the strap path and a leading edge of a downstream strap guide such that a strap moving along the strap path is spaced from the leading edge of the downstream strap guide.

7. The track assembly of claim 6, wherein the plurality of strap guides includes a first corner strap guide that defines a first curved section of the strap path, a second corner strap guide that defines a second curved section of the strap path, and an elongate strap guide extends between the first and second corner strap guides and defines at least a portion of a substantially linear section of the strap path connecting the first and second curved sections.

8. The track assembly of claim 6, wherein each of the plurality of strap guides has at least one strap retainer positioned interior of the frame to define a channel between the strap retainers and the frame, the strap path extending along the channel.

9. The track assembly of claim 6, wherein the outer frame and the strap path have a substantially rectangular shape.

10. The track assembly of claim 6, wherein one of the strap guides is a curved strap guide interposed between two of the strap guides that are linear strap guides.

11. The track assembly of claim 10, wherein the linear strap guides are substantially perpendicular to one another.

12. The track assembly of claim 6, wherein at least one of the strap guides tapers inwardly towards the strap path in the downstream direction.

13. The track assembly of claim 6, wherein each of the strap guides has a widened end and an opposing narrowed end.

14. The track assembly of claim 6, wherein each of the strap guides extends partially through an adjacent pair of the strap guides.

15. The track assembly of claim 6, wherein a length of a portion of a strap guide extending into an adjacent strap guide is less than a transverse width of a strap positioned along the strap path and captured the plurality of strap guides.

16. The track assembly of claim 6, wherein at least one of the strap guides has a narrowed leading end with respect to the strap path and a widened trailing end with respect to the strap path.

17. The track assembly of claim 6, wherein each of the plurality of strap guides includes respective strap retainers, the strap retainers together extend along nearly all of a longitudinal length of the strap path such that a strap positioned along the strap path is captured between the strap retainers and the frame.

18. The track assembly of claim 17, wherein the strap retainers extend alongside substantially all of the longitudinal length of the strap path.

19. The track assembly of claim 6, wherein the strap guides are interleaved with one another.

20. The track assembly of claim 6, wherein each of the plurality of strap guides has a closed position for retaining a strap positioned along the strap path and an open position to allow the strap to move out of the respective strap guides.

21. A method for passing a strap through a track assembly, the method comprising moving an end of a strap along a strap path located between a plurality of strap guides and an outer frame, each strap guide having a trailing end that is disposed between the strap path and a leading edge of a downstream strap guide such that the end of the strap is separated from the leading end of the downstream strap guide by the trailing end of an upstream strap guide as the end of the strap is moved downstream past the leading edge.

22. The method of claim 21, wherein moving the end of the strap further comprises sequentially moving the end of the strap out of trailing ends of the strap guides disposed within corresponding downstream strap guides.

23. The method of claim 21, further comprising:

surrounding a bundle at a strapping station using the strap from the track assembly after moving the end of the strap along the strap path and through the track assembly.

24. The method of claim 21, further comprising:

moving the strap out of the strap guides by moving the strap guides from closed positions to open positions.