Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B13/00—Bundling articles
  • B65B13/18—Details of, or auxiliary devices used in, bundling machines or bundling tools
  • B65B13/24—Securing ends of binding material
  • B65B13/32—Securing ends of binding material by welding, soldering, or heat-sealing; by applying adhesive
  • B65B13/322—Friction welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B13/00—Bundling articles
  • B65B13/18—Details of, or auxiliary devices used in, bundling machines or bundling tools
  • B65B13/24—Securing ends of binding material
  • B65B13/32—Securing ends of binding material by welding, soldering, or heat-sealing; by applying adhesive

Definitions

• This invention pertains to a gripper for a strapping machine.
• this invention pertains to a gripper for use in the strapping head of a strapping machine for plastic strapping material.
• Strapping machines are well-known in the art. There are two principle types of strapping machines, manual and automatic, table-top or freestanding machines. Strapping machines are typically designed for use with either plastic or metal (steel) strapping. These machines position, tension and seal strap around a load to bundle or secure the load.
• a typical strapping machine includes a frame-like support for the overall machine, a working area to, for example, support a load, a feed head to feed strap around the load and to retract strap prior to tensioning, a chute through which the strap is fed around the load, a strapping head to secure the strap to itself and one or more dispensers for dispensing the strap material to the strapping head.
• the strapping head serves a number of functions. First, it clamps or grips a free end of the strap (end grip) as it returns to the strapping head. Next, it clamps or grips a trailing end of the strap following retraction and during tensioning of the strap (tension grip). Then, it grips the strap again (both courses of strap) on the opposite or inside of the strap loop (loop gripper), as it severs the sealed strap from the feed or dispenser side (to permit removing the strapped load from the machine) and seals the overlapping courses of strapping together.
• One or more of the grippers may be of the self actuating type.
• a self energizing gripper that is not adversely effected by variations in strap gauge.
• such a self- energizing gripper will not fail to grip with an overly thick strap.
• such a gripper does not rely on a small contact are to secure the strap.
• such a gripper does not deform the strap as it grips the strap.
• a self-energizing gripper is used in a strapping machine having a rigid surface along which a strapping material traverses and against which the strapping material is clamped.
• the gripper includes first and second links mounted at respective first ends to the strapping machine for pivotal movement and a gripping element pivotally mounted to respective second ends of each the first and second links.
• the gripping element includes a substantially planar gripping element surface.
• the first and second links are mounted to the gripping element for pivotal movement of the gripping element along an arcuate path toward and away from the rigid surface.
• the gripping element surface remains parallel as the gripping element moves along the arc between an open gripper position and a closed gripper position.
• the self energizing gripper is not adversely effected by variations in strap gauge and as such will not fail to grip an overly thick or overly thin strap.
• the gripper uses a relatively larger contact area to secure the strap. Because the gripper has a flat contact or gripper surface, it does not deform the strap as it grips the strap.
• a present gripper includes a biasing element operably connected to the links to urge the gripping element to the closed gripper position.
• the links are mounted parallel to one another and the gripping element surface is substantially planar.
• a cam element can be mounted to one of the links such that contact with the cam urges the gripping element to the open gripper position.
• the parallelogram link arrangement is configured such that an axis of each of the links forms an angle with the rigid surface and movement of the gripping element along the arcuate path toward and away from the rigid surface is through an angle of less than 90 degrees and maintains that gripping element surface parallel to the rigid surface.
• FIG. 1 is a front view of an overhead strapping machine having a self-energizing gripper embodying with the principles of the present invention
• FIGS. 2A and 2B are an enlarged partial views of the self energizing gripper in the closed and open gripper states, respectively; [0019] FIG. 3 is an illustration of the strapper showing the gripper in an open state; and
• FIG. 4 is an illustration of the strapper showing the gripper in a closed state.
• the strapper 10 includes, generally, a frame 14, a strap chute 16, a sealing head or module 18, a feed or drive head (or module) 20 and a strap dispenser 22.
• the dispenser 22 and feed head 20 can be separately located (generally nearby), to facilitate maintenance on the dispenser 22 (e.g., reloading strap reels R) and the feed head 20 as needed.
• Packages P to be strapped are positioned within the chute 16. Packages can be of any size that fits within the chute 16.
• the sealer module 18 has a number of grippers. For example, an end grip 24 clamps the free end F of the strap S as it returns to the strapping head 18. A tension grip 26 clamps the trailing end T of the strap following retraction and during tensioning of the strap, and a loop grip 28 clamps both courses of strap on the opposite or inside of the strap loop L, as the sealed strap loop L is severed from the feed or dispenser 22 side and the seal (sealing the overlapping courses of strapping together) is formed.
• Some of the grippers are actuated by a mechanical or electromechanical element to exert the full force necessary to clamp the strap.
• a cylinder or cam element 30 can exert a force on a gripper element (for example loop grip 28) that clamps down onto the strap S.
• Other grippers are of the self-energizing type in which the tension force of the strap S urges the gripper tighter.
• the present self-energizing gripper 12 uses a gripping element 34 that has a relatively large, flat or relatively flat gripping head surface 36.
• the element 34 is mounted by multiple (preferably two) pivot links 38, 40, for pivotal movement, into and out of engagement with the strap S, which is passed between the gripping element 34 and a platen or anvil 42.
• the platen 42 is a rigid, flat or substantially flat surface along which the strap S traverses toward the sealing head 18.
• the pivot links 38, 40 are fixed (but mounted for pivotal movement) at respective pivot locations 44, 46 (to the strapper 10) and are pivotally mounted to the gripping element 34 at their opposite ends as indicated at 48, 50.
• the links 38, 40 are parallel (e.g., A 38 and A 40 are parallel) and equal length (e.g., d 38 and d 40 between respective pivots 44/48 and 46/50) and as such, although the gripping element 34 moves in a pivotal or arcuate motion, the gripping head surface 36 remains parallel to the platen 42 surface as the gripping element 34 moves or pivots between the open and closed gripper positions (FIGS. 3 and 4, respectively).
• This parallelogram link configuration provides means for mounting the element 34 to the strapping machine 10 such that the element 34 pivots into and out of contact with the strap S, but the contact surface 36 remains parallel to the strap S to maximize the contact area (indicated generally at 52).
• the angle ⁇ through which the links 38, 40 (and thus the element 34) pivot is acute, i.e., less than 90 degrees.
• the contact area 52 between the gripping head surface 36 and the strap S is substantially larger than known single pivot grippers. Accordingly, there is less opportunity for the gripper 12 to deform the strap S when the gripping head surface 36 is in contact with the strap S. Moreover, the flat gripping head surface 36 is substantially less sensitive to variations in strap thickness or gauge t s , in part because of the flat surface 36, but also because of the increased distance d 38 , d 40 between the fixed pivot axes 44, 46 and the gripping head surface 36. This also provides a relatively large contact angle ⁇ .
• the present gripping head surface 36 is textured or roughened, as by forming a diamond-pattern in the surface 36.
• the gripping element 34 is urged toward contact with the strap
• the spring 54 is intended to urge the gripping head element 34 into contact with the strap S, rather than to provide a substantial contact force between the gripping element 34 and the strap S.
• the spring 54 is mounted to the machine 10 at a location (indicated at 56) that is fixed relative to the moving gripper 12.
• the spring 54 contacts one of the links (an outboard link 38) on a side of the link 38 to urge the element 34 into contact with the strap S and platen 42.
• a release function for the gripper 12 is provided in two ways.
• the opposite link (the inboard link 40) includes a cam element 60 mounted thereto. The cam 60 is disposed such that a force applied to the cam 60 (as indicated by the arrow at 62) will urge the element 34 (and the links 38, 40) to pivot to open the gripper 12.
• movement of the gripping element 34 to open the gripper 12 is against the spring 54 force.
• Contact on and movement of the cam 60 can be effected by relative movement of the cam 60 and a release element, or movement of the strapping head and or tensioning assembly such that the cam 60 contacts a (relatively) fixed element (see surface 64 in FIG. 3) on the strapping machine 10.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Basic Packing Technique (AREA)

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Publications (1)

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• 2007
  • 2007-09-07 US US11/851,984 patent/US7428867B1/en active Active
• 2008
  • 2008-08-13 JP JP2010524081A patent/JP5199368B2/ja active Active
  • 2008-08-13 EP EP08797747A patent/EP2183161B1/en active Active
  • 2008-08-13 AU AU2008296650A patent/AU2008296650B2/en active Active
  • 2008-08-13 WO PCT/US2008/072963 patent/WO2009032490A1/en not_active Ceased
  • 2008-08-13 CA CA2694174A patent/CA2694174C/en active Active
  • 2008-08-13 KR KR1020107004890A patent/KR101507135B1/ko active Active
  • 2008-08-13 ES ES08797747T patent/ES2388362T3/es active Active
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