US RE31,353 E · Expanding strap loop forming and friction fusion machine

Abstract

An automatic strapping apparatus is disclosed which forms a small primary loop from strap; expands the primary loop to a larger predetermined diameter loop which can be placed about a package to be strapped; and tensions, friction fuses, and severs the strap. The small primary strap loop is formed by feeding a free end of a length of strap into a circular cup through a slot in the cup sidewall so that the free end is guided by the inner periphery of the cup to form a loop with the strap free end overlapping a portion of the loop. The cup is moveable from an upper position around the formed primary loop to a position out of contact with, and below, the loop. A cylindrical gripper is provided inside the loop and a smooth-surfaced anvil is provided on the exterior of the loop for engaging the overlapped portion of the loop therebetween so that the strap free end is restrained by the gripper while the overlapped portion of the loop can be continued to be fed to expand the loop to a larger predetermined diameter. The strap free end remains restrained by the gripper as the strap is tensioned to tighten the loop about the package. The gripper is then rotatably oscillated at a high frequency to cause the strap free end to slide against the overlapped portion of the loop thereby generating heat and fusing the strap free end to the overlapped portion of the strap loop. A cutter is provided to sever the tightened and fused loop from the standing length of strap.

Claims12

Dependent claims

[An] In an apparatus for forming, tensioning, and securing a strap loop about a package, said apparatus comprising:

means for [feeding] guiding a length of strap [in a path] to form a primary strap loop with a portion of the strap loop overlapped by the free end of the length of strap;
means for restraining said free end of the strap from movement while feeding the standing length of the strap to expand the loop to a predetermined size;
means for tensioning the strap to tighten the loop about said package;
and
means for joining said free end of the strap and an adjacent overlapped portion of the loop ;
the improvement in the apparatus characterized in that said means for guiding the strap to form a primary loop is free of guides for acting on the inside of the loop but includes an arcuate guide member having an inner surface for acting on the outside of the loop for guiding only one surface of the strap along the inner surface of the guide member to form said primary strap loop, said guide member defining a slot and being positionable to receive said length of a strap through said slot, said slot being open to one edge of said guide member;
the improvement further characterized in that said guide member is movable relative to said restraining means;
and the improvement further characterized in that said apparatus includes means for moving said guide member relative to said restraining means between a first position wherein said primary strap loop is formed and a second position spaced away from said first position to allow said primary strap loop to be expanded to said predetermined size out of contact with said guide member .

5 more elements

[11. The apparatus in accordance with claim 6 in which said means for restraining said free end of the strap comprises a rough-surfaced member and an opposed smooth-surfaced member for pressing said free end of the strap and an adjacent overlapped portion of the loop

therebetween.] 12. The apparatus in accordance with claim [11 including] 10 in which said means for effecting relative movement includes means for moving said [smooth-surfaced member] anvil to bear against a side of an adjacent portion of the loop in contact with said strap free end whereby a side of said strap free end is pressed against said
rough-surface gripping member. 13. The apparatus in accordance with claim [11] 10 further comprising strap edge locator means for guiding at least one of the two edges of a portion
of the length of strap as the strap is fed. 14. The apparatus in accordance with claim 13 in which said strap edge locator means comprises a plate mounted adjacent said [smooth-surface member] anvil and substantially parallel to the plane of said primary strap
loop. 15. The apparatus in accordance with claim 13 in which said strap edge locator means comprises a flange on one end of said rough-surfaced gripping member. 16. An apparatus for forming, tensioning, and securing one of a non-metal strap and a metal strap with a non-metal coating in a loop about a package, said apparatus comprising:
a frame having a package support surface;
means for supporting a length of strap on edge in a strap transport zone below said package support surface;
a motor driven traction wheel and adjacent idler wheel located in said strap transport zone and adapted for engaging said length of strap therebetween for feeding said length of strap in one direction for forming a loop and for drawing said length of strap in the reverse direction to tension said loop;
a cylindrical weld head located in said strap transport zone with the axis parallel to the sides of the strap in said zone and having a peripheral gripping surface adapted for contacting a side of said strap;
a smooth-surfaced anvil [member] located adjacent said weld head in said strap transport zone;
means for moving said anvil in said zone towards said weld head to engage portions of the strap therebetween;
a hollow cylindrical guide in said strap transport zone surrounding said weld head and having slot means for accommodating said movement of said anvil [member] towards said weld head and for accommodating the passage of said length of strap between said anvil and said weld head from the exterior to the interior of said guide when said length of strap is fed into said guide to form a primary strap loop with a portion of the strap loop overlapped by the free end of the strap, said guide being moveable between a first position in alignment with said strap transport zone and a second position, below the first position, wherein said primary strap loop can be expanded to a larger loop of predetermined diameter when said free end of the strap is pressed between said weld head gripping surface and an adjacent overlapped portion of the loop by said smooth-surfaced anvil;
means connected to said cylindrical weld head for oscillating the head at a frequency sufficiently high to fuse said free end of the strap to an adjacent overlapped portion of the loop after the larger strap loop has been placed around said package and tensioned;
and
cutter means for severing the standing portion of the length of strap from
the [tightened] tensioned and fused loop. 17. The apparatus in accordance with claim 16 including control means responsive to the rotation of said traction wheel for moving said cylindrical guide from said first position to said second position after formation of said
primary strap loop in said guide. 18. The apparatus in accordance with claim 17 in which said traction wheel is secured to a shaft and in which said control means includes a clutch member engageable with said shaft.
The apparatus in accordance with claim 16 in which said means for moving said anvil includes an air operated piston and cylinder actuator.
. The apparatus in accordance with claim 18 including automatically actuated valve means for variably pressurizing said piston and cylinder actuator to bias said anvil [member] with variable force against said weld head with portions of strap impressed therebetween.

15 more elements

In an apparatus for forming, tensioning, and securing a thermoplastic strap in a loop about an article;

means for feeding a length of strap to form a primary strap loop;
means for expanding the loop to a predetermined size;
means for tensioning the loop about the article;
and means for connecting the overlapping strap loop ends;
the improvement that includes:
a weld head having a peripheral gripping surface adapted for contacting a side of the strap;
a generally smooth-surfaced anvil located adjacent said weld head;
means for moving said anvil away from said weld head to permit passage of the free end of said strap past said anvil and for moving said anvil towards said weld head to engage portions of the strap therebetween with a predetermined force;
an arcuate guide member substantially surrounding said weld head, said guide member having slot means for accommodating the movement of said anvil towards said weld head and for accommodating the passage of said length of strap between said anvil and said weld head from the exterior to the interior of said guide member when said length of strap is fed into said guide member to form a primary strap loop with a portion of the strap loop overlapped by the free end of the strap, said guide member being movable between a first position for receiving said strap while forming said primary strap loop and a second position spaced from the first position wherein said primary strap loop can be expanded without interference to a larger loop of predetermined size when said free end of the strap is pressed between said weld head gripping surface and an adjacent overlapped portion of the loop by said smooth-surfaced anvil;
and
means connected to said weld head for oscillating said weld head at a frequency sufficiently high to fuse said free end of the strap to an
adjacent overlapped portion of the loop.

9 more elements

Dependencies are inferred from the claim text.

Expanding strap loop forming and friction fusion machine

Life of this patent

Expanding strap loop forming and friction fusion machine

Life of this patent

Abstract

Claims12