CA1063501A - Machine and method for forming a strap loop about a package - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A machine and method is disclosed for forming, tensioning and sealing a strap loop about a package and then severing the sealed loop from the trailing length of strap. A 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 movable 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 grip-per 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.

Description

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BACKGROUND OF THE INVENTION
In the past, Signode Corporation, the assignee of the entire interest of the present invention, has developed several methods and machines for forming a strap ".
-~ loop aibout a package, tensioning the loop, and joining tihe overlapping portions of the tensioned loop by friction-fusion or other means. Such methods and apparatuses are typified by those disclosed and claimed in the U.S. patent to Sten-saker et al., No. 3,442,732S to Vilcins, No. 3,442,733~ to Ericsson, No. 3,442,734s to Stensaker, No. 3,442,735~ to Kobiella, No. 3,442,203; and to Ericsson, No. 3,58~572.
Some strapping machines, such as the machine disclosed in the Kobiella U.S. Patent No. 3,442,203, are of the completely automatic type, i.e., one which automa-tlcally feeds a thermoplastic strap around a package from a strsp supply source, grips the leading end of the strap, !
; withdraws the standing length of the strap to tension the strap loop, friction-fuses the overlapping portions of the loop, and severs the loop from the standing length of the strap. However, this type of automatic strapping machine has a relatively large, ring-like, rigid chute into which the package is inserted and in which the strap is fed to form a closed loop around the package. With therimoplastic strap, problems have been encountered wherein the strap may buckle or ~am in the chute as the strap is fed around the package. ~his is due to the relatively low column strength of the thermoplastic strap. In addition, a ring-like chute adds considerable bulk to the machine and requires a work ;~ space, or operating space, large enough to accommodate the chute and large enough to provide insertion and removal areas -3- '~$
' for the package.
It would be desirable to devise a strapping method and machine wherein the strap loop could be formed without the need for a large, ring-like chute into which a packaqe must be inserted. Use of such a method would re-quire relatively less space than the present method that requires a chute. Thus, a method that does not require a chute could be performed on a work table or desk and could be used for strapping small packages.
; ; 10 Automatic strapping machines which use ring-like chutes to form the loop about the package are some-what inefficient with respect to strapping different size package~. For example, if a strapping machine is intended to strap large packages, say three feet in diameter, then the strap chute must be at least throe feet in diameter.
If, subsequently, the machine is used to strap much smaller packages, say one foot in diameter, then the strap loop fonmed around the smaller package is initially three feet in dlameter and the machine must withdraw a substantial amount of trailing strap during the tensioning process to decrease the diameter of the loop and tighten it ~bout the one-foot diameter package. This is obviously inefficient.
Therefore, it would be desirable to provide a method and ~ . . . .
machine for forming a strap loop of any desired size. Such a method and machine would advantageously be used in strap-ping operations where the size of the packages would vary.
Thermoplastic strapping machines currently avail-able also suffer from some drawbacks relating to the forma-tion of the friction-fusion weld. In order to form a friction-fu~ion weld on the overlapped portion of the strap loop, an ; _4_ ':

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~ 1063501 anvil or bearing member must be inserted between the package and the strap loop to provide a rigid bearing surface against which the overlapping strap portions are pressed by an oscil-lating weld member. The anvil member prevents the strap loop from lying flat against the surface of the package at that point and therefore introduces ~lack into the loop. However, owing to the flexibility of the strap, a tight loop can usually be obtained with large and slightly resilient pack-ages. Unfortunately, though, with very ~mall packages and/
or with package~ having relatively rigid, incompressible surfaces, the amount of slack introduced into the ~trap loop by the inserted anvil can be significant and can result in a loose strap loop when the anvil i8 retracted from between the strap and the package. Accordingly, it is de~irable to provide a method and apparatus for welding the strap loop in a manner that does not require the lnsortion of an anvil member between the strap and the package.
SUMMARY OF THE INVENTION
The method and apparatus of the present invention utillzes a novel concept of first forming a small, or pri-mary, strap loop and then expanding the formed primary loop to a larger predetermlned size. Formation of the primary loop can be accomplished without the use of a ring-like chute into which the package to be strapped must be placed.
In the preferred embodiment of the method of the present invention, the primary strap loop is formed by feeding a length of strap into a substantially circular guide or cup 80 that the strap free end is guided around in a circle by the inner periphery of the cup to form a loop with the strap free end overlapping a portion of the ,. _ __ _ _ _. _ _ . ,, . _ ... . . .. _ .. . . . . .. .. . .

~: i063501 loop. Next, the formed primary strap loop is held, gripped or guided to maintain the primary strap loop in the plane of its original formation and the circular cup is lowered away from the primary loop in a direction normal to the plane of the loop. The loop i8 then expanded to a size large enough to fit around the particular package to be strapped. More specifically, the strap free end is gripped or restrained from further movement while the standing length ; of strap is continued to be fed to expand the loop to the desired size. The package i8 then moved near, or over, a portion of the expanded loop and the loop is placed about the package, after which the loop $8 tensioned to tighten ; it about the package. When the loop has been sufficiently tightened, the strap free end i8 connected or ~oined to an ad~cent overlapping portion of the loop by appropriate means, such as by friction fusion, application of an lndependent seal, or by formation of an interlocking slit type ~oint.
The completed loop can then be severed from the trailing length of strap.
In the preferred embodiment of the apparatus of ~i; the present invention, a supply of strap is threaded in guideways in a horizontal ~trap transport zone below a hori-zontal package support surface. The strap is further threaded between a traction wheel and an idler wheel, the traction wheel being driven by an electric motor to advance the strap for-ward when feeding the strap to form a loop and to withdraw the strap backwards when tensioning the loop.
A cylindrical cup is provided to receive the free end of the strap as it is fed forward. The strap enters the cup through an opening or slot in the cylindrical side of '' :~,, the cup and impinges upon the interior surface of the cup where the strap is further guided in a closed arcuate path to form a small primary strap loop with the free end over-lapping a portion of the strap loop. The cup is mounted for movement between thiis first, strap receiving, position and a second position beneath the first position. After the strap loop has been formed, the cup is lowered to the second position and the formed primary strap loop, being supported by thie standing length of strap in the strap transport zone guideways, remains suspended at the elevated first position above the lowered cup.
A combination cylindrical gripping/welding member extends through the bottom of the cylindrical cup and up .~., into the inside of the formed primary strap loop. A mov-able anvil member is provided on the exterior of the formed strap loop and is movable toward and away from the combina-tion gripping/welding member. When the cup has been moved to the lowered position below the fonmed primary strap loop, the anvil member is moved toward the gripping/welding member and presses the overlapped portion of the strap loop there-between. The gripping/welding member has a rough peripheral gripping surface which engages a side of the strap free end , .
while the anvil surface contacting the side of the over-lapped portion of the loop is smooth. Thus, as the strap continues to be fed, the strap free end is restrained from movement and the overlapped portion of the loop slides between the strap free end and the smooth surface of the anvil to expand the loop to a larger diameter. When a pre-determined larger diameter has been reached, the feeding of the strap is terminated.

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- A package, having been placed upon the raised package support surface adjacent the overlapped portion of the strap loop, is then ved forward to overhang the horizontally oriented loop. The operator then grasps the strap loop and lifts it around the package by twisting the 7' loop about the restrained overlapping strap area to a vertical orientation about the package. Reversal of the traction wheel withdraws the standing portion of the length of strap to tighten the loop about the package. When the strap is tensioned to tighten the loop, the gripping/welding member is still engaged with the strap free end to prevent its movement and to allow the loop to be tightened.
As the loop is tightened about the package, the ; ~ strap free end and the adjacent overlapped loop portion of the strsp between the anvil member and the gripping/welding ; j, member are oriented with their sides perpendicular to the bottom surface of the package and lying in the plane of the loop about the package. In this configuration, the strap loop i8 next friction-fusion welded in the overlapping , area. The gripping/welding member is rotatably oscillated at a high frequency to move the strap free end back and `~ forth relative to the overlapped portion of the strap loop thereby generating sufficient friction heat to fuse the strap free end to the overlapped portion of the loop. A
cutter blade is provided to sever the standing length of : . .
strap from the loop. Next, as the anvil is retracted away from the gripping/welding member, the twisted, overlapped portion of the loop twists back to assume the nonmal orientation lying flat against the package. The package can then be removed from the apparatus.

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-Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and embodi-ments thereof, from the claims and from the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings forming part of the specification, and in which like numerals are employed to designate like parts throughout the same, Figure 1 is a partial perspective view of a preferred embodiment of the apparatus of the present invention;
Figure 2 is a partial perspective view similar to Figure 1 and showing a package on the apparatus with the strap cup in raised position7 Figure 3 is a partial perspective view similar to Figure 2 showing the strap cup in the lowered position and the strap being expanded to a predetermined larger dia-meter;
Figure 4 is a partial perspective view similar to Figure 3 showing the expanded strap loop being located about the package;
Figure 5 is a partial perspective view similar toFigure 4 showing the strap loop tensioned about the package;
Figure 6 is a partial fragmentary perspective view of the apparatus shown in Figure l;
Figure 7 is an enlarged, partial, fragmentary top view of the apparatus shown in Figure 2 with the strap cup : in raised position and a length of strap formed into a loop within the cup;

- Figure 8 is a sectional view taken generally along the plane 8-8 of Figure 7;
Figure 9 is an enlarged, partial, fragmentary - top view similar to Figure 7 but with the strap cup in the lowered position and the strap loop expanded to a larger . ~ predetermined diameter;
Figure 10 is a sectional view taken generally along the plane 10-10 of Figure 9;
Figure 11 is a sectional view similar to Figure . ~ .
.,. 10 10 showing the expanded loop located about a package;
`.: Figure 12 is an enlarged, partial top view of the apparatus shown in Figure 6 showing in detail the strap tension sensing mechanism;
Figure 13 is a schematic diagram of the pneu-matic control system for the apparatu~ of the present inventian;
Figure 14 is a simplified control block diagram for the apparatus of the present invention;
Figure 15 is a top view similar to Figure 2 of the strap loop forming area of a second embodiment of an apparatus for strapping a package according to the method ; of the present invention;
Figure 16 is a view similar to Figure 15 showing .~ the method of expanding the strap loop to a larger diameters ~: Figure 17 is a cross-sectional view taken generally ;; ~ along the plane 17-17 of Figure 15;
Figure 18 is a view similar to Figure 8 illus-F trating the strap loop forming area of a third embodiment : of an apparatus for strapping a package according to the 30 method of the present invention;
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Figure 19 is a cross-sectional view of the strap loop forming area of a fourth embodiment of an apparatus for strapping a package according to the method . i,..~
of the present invention;
Figure 20 is a reduced cross-sectional view taken generally along the plane 20-20 of Figure 19;
Figure 21 is a top view of the strap loop form-; ing area of a fifth embodiment of an apparatus for strap-: ping a package according to the method of tho present invention;
Figure 22 is a simplified diagrammatic top view of the strap loop forming area of a sixth embodiment of an ; apparatus for strapping a package according to the method of the present inventian~
.~ : Figure 23 is a view of the sixth embodiment, similar to Figure 22, illustrating th- formation of a primary strap loop;
Figure 24 is a view of the sixth embodiment, similar to Figure 23, illustrating the formation of an expanded strap loop;
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Figure 25 is a view of the sixth embodiment, similar to Figure 24 but much reduced in scale, to show an expanded strap loop pl~ced about a package;
:~ Figure 26 i8 a top view of the strap loop forming ~ area of a seventh embodiment of an apparatus for strapping };:: a package according to the method of the present invention;
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Figure 27 is a cross-sectional view taken gener-ally along the plane 27-27 of Figure 26 showing a primary -: strap loop being lifted from a guide;
Figure 28 is a top view of the seventh embodiment, .
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`1063501 similar to Figure 26, showing an expanded strap loop.
Figure 29, appearing on the same sheet of draw-ings as Figures 20 and 21, is a cross-sectional view of the strap loop forming area of an eighth embodiment of an apparatus for strapping a package according to the method .~,,~ .
of the present invention;
Figure 30, appearing on the same sheet of draw-ings as Figures 20 and 21, is a cross-sectional view taken generally along the plane 30-30 of Figure 29; and Figure 31, appearing on the same sheet of draw-ings as Figures 20 and 21, is a simplified, partially schematic diagram illustrating another form of a primary `
strap loop according to the method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
While this invention is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail several preferred embodiments of the invention. It should be understood, however, that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodi-ments illustrated.
For ease of description, the various embodiments of the apparatus that may be used for strapping a package according to the method of this invention will be described in normal operating position, and terms such as upper, lower, horizontal, etc., will be used with reference to this normal operating position. It will be understood, however, that the apparatus which is used to effect the ~3~method of this invention may be manufactured, stored, transported, sold and operated in an orientation other than the normal operation position described.
The apparatus illustrated herein which may be . .

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: 1063501 used to effect the method of this invention has certain conventional drlve mechanisms and control mechanisms which, though not fully illustrated or described, will be apparent to those having skill in the art and an understanding of the necessary functions of such drive mechanisms causing proper operation of the apparatus as will be explained.
A preferred embodiment of the expanding strap loop forming and friction fusion apparatus in accordance with the present invention is designated generally as 20 in Figure 1.
Preferably, the apparatus is of a size suitable for being placed on a worktable or desk and is advantageously used to strap rectangular parallelpiped-shaped packages having dimensions of between 5 and 40 inches on each side. How-ever, the apparatus can accommodate much larger or smaller packages and packages of different shapes.
As shown in Figure 2, the apparatus 20 of the present invention has a package support surface 22 for supporting a package 24. The apparatus 20 has a lower surface or shoulder 26 stepped below the elevation of the package support surface 22.
OUTLINE OF THE MAJOR STEPS OF THE STRAPPING SEQUENCE
To aid in understanding the details of con-struction of the apparatus 20, a brief outline of the process of forming and securing a strap loop about a package will first be given.
As illustrated in Figure 2, a package 24 is first placed upon the package support surface 22 near shoulder 26. A cylindrical cup 28 is raised from a posi-tion below the surface of shoulder 26 to an elevated posi-tion above the surface of shoulder 26. By a novel means, :

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as will be described in detail hereinafter, a length of strap i8 fed into the cup to form a primary strap loop.
The cup 28 is then lowered to a position below the surface ; of shoulder 26 while the loop i8 maintained at the higher elevation where it is expanded to a predetermined larger diameter loop 30 as illustrated in Figure 3. Next, the operator slides the package 24 forward to overhang shoulder 26 and then places the expanded loop 30 about the package 24 as illustrated in Figure 5. The strap is tonsloned to draw the loop tight about the package. The entire process is completed when the tensioned loop is friction fusion welded to form a connection and then severed from the .. ~ .: .
~ strap supply.
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The speclfic features of the apparatus used to accomplish the above-described package strapping process will next be discussed in detail. The ma~or foatures or mechanisms of the apparatus ares 1) the strap loop form-ing mochanism; 2) the strap feed and tensioning mechanism;
3) the ~trap loop friction fusion mechanism; 4) the strap ~evering mechanism; 5) the pneumatic actuat$on system, and 6) the electrical control system.
STRAP LOOP FORMING MECHANISM
A novel feature of the present invention is the mechanism automatically for first forming a primary strap loop that can be subsequently expanded to any larger size.
The apparatus for forming the primary strap loop is most clearly shown in Figures 6 through 11.
~ By a strap feed mechanism described hereinafter, i~ the strap is fed into a guide means. A circular band ~; 30 member, or cup 28, provides a circular guide means for ` ' ' , ~ 1063501 forming the primary strap loop. Cup 28 is a substantially cylindrical member and may or may not have open ends. In the preferred embodiment illustrated, cup 28 has a par-. .
tially closed bottom and an open top. A portion of the vertical cylindrical wall of the cup 28 is cut away to form a relatively large opening or slot 34 for receiving a length of strap 36 as shown in Figure 7. The cup 28 guides the strap free end 38 in a closed arcuate path whereby the free end 38 is directed back upon the length of strap 36 to form the initial primary strap loop with the free end of the strap overlapping a portion of the formed strap loop.
The cup 28 is movable between an upper, or raised position, and a lowered position. The mechanism for ralsing and lowering the cup 28 may be of any appropriate type. As illustrated in Figure 6, the cup 28 i~ secured to a drive member 64 which i8 attached to an electric solenoid actuator 66.
The length of strap 36 is oriented with its side ~urfaces perpendicular to the plane of the package support 8urface 22 and is guided beneath the package support surface 22 in a strap transport zone 40 which lies between the pack-age support surface 22 and the plane of shoulder 26. The ~trap transport zone 40 has a thickness substantially equal to the width of the length of strap 36 and is essentially a stratum in which the length of strap 36 is fed, guided, formed into a primary loop, expanded into a larger loop, tensioned, friction welded and severed. In the raised posi-tion tas illustrated in Figure 2), the cup 28 lies in the .: .
strap transport zone 40. In the lowered position (as illustrated in Figures 1 and 6), the cup 28 lies below the ~ ` ' ; .

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strap transport zone 40. The length of strap 36 is guided within the strap transport zone 40 by appropriate guideways 42 as illustrated in Figure 6. The strap is also fed for- -ward and tensioned backwards through the guideways 42 in zone 40 by appropriate traction drive means as will be described hereinafter.
During loop formation, the strap free end 38 i9 1) guided into the cup slot 34, 2) maintained within the ,~,. -~ ; ~, cup 28 by upper and lower guides, and 3) restrained above cup 28 during lowering of cup 28 and subsequent expansion of the loop. These guides and strap restraining means will be described with reference to Figure 7. Adjacent slot 34 is an anvil 44 which is mounted on movable slide 46. A
portion of anvil 44 adjacent the length of strap 36 has a ~mooth-surfaced polyurothane pad 48 ~ecured thereto for guidlng and contacting length of ~trap 36 as wlll be described hereinafter. Opposite the polyurethane pad 48 is a cylindri-cal member, or weld head 52, which uniquely serves two func-tionss 1) gripping the strap free end 38 and 2) welding the free end to the overlapped portion of the loop. The welding function will be described later. At this point, just the l~ ~ gripping or restraining feature of the weld head will be discussed. The weld head 52 is mounted on shaft 53 and is a substantially cylindrical member having a rough, peri-pheral gripping surface 54 adapted for contacting a side of the strap free end 38. Both the weld head 52 and the anvil 44 lie in the strap transport zone 40 as illustrated in ~ ,. 1 , Figure 8. The anvil 44 is movable, by air cylinder actuator means to be described later, within the transport zone 40 in a horizontal plane towards and away from the weld head . I
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4 52- When the cup 28 is in the raised position as illustrated in Figures 7 and 8, the anvil 44 can be ved towards the weld head 52 to a position spaced away from the weld heaa gripping surface 54 where a portion of the anvil 44 contacts the cup 28 at abutment surface 56 and remains biased there-against. In this position there is sufficient clearance between the weld head gripping surface 54 and the polyure-thane pad 48 to allow the length of ~trap 36 and the over-lapping free end 38 to lie therebetween. When the cup 28 is lower-d below the surface of shoulder 26, the anvil 44, being biased towards the weld head 52, moves toward the weld head 52 to bring the polyurethane pad 48 into contact with the length of strap 36 lying therebetween to restrain the over-lapping strap free end 38 from ~ovement.
As lllustrated in Figure 6, the movement of anYil slide 46 18 effected by a pneumatic cylinder actuator 120 whioh acts through a piston rod 122 connected on one end to the cylinder piston ~not shown) and on the other end to the . .
slide 46.
Referring now to Figure 7, the detailed formation of the primary strap loop will now be described. First, the free end 38 of a length of strap 36 is fed forward in the strap transport zone 40 between the strap transport guideways 42 and through aperture 34 of cup 28. The strap .~
~` free end 38 is guided by polyurethane pad 48 and a portion of anvil 44 as it enters the interior of cup 28. The strap free end 38 is guided by the interior surface of cup 28 in a closed arcuate path to form an initial primary loop with the free end 38 overlapping a portion of the loop between -~ 30 the anvil 44 and the weld head 52. By suitable control means ., :
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as will hereinafter be described, the feeding of the strap length 36 i8 terminated when the primary loop has been formed . essentially as illustrated in Figure 7.
^~ ~ It i8 desirable during the primary loop formation stage, as well as during subsequent tensioning and welding stages, to maintain the overlapped portion of the strap length 36 and the free end 38 in the elevation of the strap - transport zone 40. To this end, appropriate upper and lower guides are provided. A flange 60 is provided in the lower :~ 10 ond of the weld head 52 for keeping the overlapped portion ; of the strap length 36 and strap free end 38 from running below weld head 52. A slide cover 62 is secured to, and movable with, slide 46 above the strap transport zone 40 to prevent the overlapped portion of tho length of strap 36 and the strap free end 38 from riding above the weld head 52 and the polyurethane pad 48.
After the primary strap loop has been formed, the cup 28 must be lowered from its elevated position in the . . i ~i strap transport zone 40 to a second position below the strap ~;' " 20 transport zone 40. As the cup i~ lowered,the formed pri-mary strap loop does not ride in the cup 28 to the lowered ` position, but rather slides out of the cup and remains at ~.. .
: the upper position. This is due to the combination of the ~ : relatively small diameter of the cup 28, the stiffness of . . .
the strap, the low coefficient of friction between the strap and the cup, and the fact that the strap length 36 i8 sup-~ ; ported on its bottom edge in the strap transport zone guides ~ 42. Consequently, when the cup 28 is lowered, the formed a; ~ primary strap loop is maintained at the elevation of the ;~ 30 strap transport zone 40 above the top surface of the shoulder . 26.

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After the cup 28 is completely lowered away from the primary strap loop, any tendency of the loop to uncoil or unwind is resisted. Owing to the proximity of the weld head 52 and the polyurethane pad 48 on opposite sides of the overlapping strap portions of the loop, the loop is not able to unwind and is thus maintained in a loop.
A novel combination of mechanisms is used to expand the formed primary strap loop to a larger loop of predetermined diameter. With the cup 28 in the lowered position as illustrated in Figures 9 and 10, slide cover 62, anvil 44 and polyurethane pad 48 move clo~er toward weld head 52 by slide 46 under the influence of a biasing means described hereinafter. Anvil 44 is moved forward to force polyurethane pad 48 against the strap loop in a region where the strap free end 38 overlaps the overlapped portion of the loop formed by the length of strap 36. The polyurethane pad 48 then contacts a side of the length of strap 36 to force both the length of strap 36 and the overlapping ; strap free end 38 against weld head 52. By means that will be described later, the polyurethane pad 48 is maintained l against the loop with a relatively small amount of force ; such that the strap free end 38 is restrained from moving by the weld head roughened peripheral gripping surface 54.
However, the force is low enough (about 2 pounds) to permit the overlapped length of strap 36 to slide forward between ~i the strap free end 38 and the smooth - surfaced polyurethane pad 48 when the length of strap 36 is fed to expand the loop. Preferably, during the expansion of the primary ... . .
strap loop, the surface of shoulder 26 provides the support for the bottom of the strap loop as it expands.

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Though the surface 54 of the weld head 52 is prefer-ably roughened (espeeially on account of its gripping function during the subsequent frietion fusion process to be deseribed - below), it need not necessarily be 80. Insofar as the hoad 52 functions during the loop expansion process, the head 52 need ~ only have some sufficiently relatively greater coefficient of ; sliding frietion than the pad 48. Alternatively, the pad 48 eould be replaeed by a cylindrical roller mechanism which would rotate about an axis parallel to the weld head shaft 53 to allow ; 10 feeding and tensioning of the strap. The roller could be lockod against rotation, if neeessary, during tho subsequent frietion fusion proeess (to be deseribed below).
, After the loop has been expanded to the predetermined c-~, larger diameter and placed around tho package 24 as shown in ~ Figures 4 and 11, the loop 30 18 tensioned and tightened about ; ~ the paekage 24. The detail~ of th meehanism for applying l ten~ion to the strap wlll be diseus~-d later. It is fir~t -~ nece-sary to deseribe the aetion of the polyurethane pad 48 ; and the weld head 52 during the tensioning proeess. At the beginning of the tensioning phase, the strap loop 30 is dis-posed about the paekage 24 as illustrated in Figure 11. At I
this timo, the cup 28 is in tho lowerod position below the ~urface of the shoulder 26. The strap loop 30 i8 tensioned about the paekage 24 to form a tight loop as illustrated in Figure 5.
During tensioning, a tensile foree is transmitted along the ~¦ length of the strap 36 which is eonsiderably higher than the ;~l small eompressive force whieh exi~ts in the portion of the strap." ., between the strap feed meehanism and the polyurethane pad 48 as the strap is being fed to form the expanded loop. Consequently, during tensioning the higher force oceurring in the ~trap would . ",.~
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tend to pull the strap free end 38 from its restrained engagement against weld head 52. To overcome this possibility, the poly-urethane pad 48 is forced against the strap and weld head 52 during tensioning with a large force to cause strap free end 38 to remain restrained against~the wëld head 52. In the preferred embodiment o. the present invention, it has been found that a force of about 30 bo 40 pounds is sufficient to m~intain the strap free end 38 between the polyurethane pad 48 and the weld head 52 as ~the overlapped length of strap 36 is tensioned. Typically, the ; ~ 10 ~trap loop is tensioned to about 10 to 15 pounds.
; During the tension~ng process, as illustrated in Figure 11, the upper edge ofthe strap, in the region of the ~trap overlap between the polyurethane pad 48 and the weld ;head 52, ~s nearer the bottom ~urface of the package 24 than - ;' i8 the bottom edge of the ~trap. Preferably, the strap loop 30 is maintained in the 90 twist orientation illustratea in Pigure 11 such that both the upper and lower edges of the strap in the region between the polyurethane pad 48 and the weld head 52 are located in the plane of the loop as the loop ,~ 20 is tensioned about the package 24. Although the sliding sur-" ~ . .
face of polyurethane pad 48 and the opposed gripping surface 54 of weld head 52 are shown in Figure 11 as being perpendicula~
to the slide cover 62 and to the bottom of the package 24, such ,. ~
~orientation is not necessarily ~equired. The surfaces on both ~
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the polyurethane pad 48 and the weld head 52 could be angled witb respect to the plane of the strap loop 30 about the pack-age 24. ~ -During the tensioning process, slide c~ver 62 lies between the bottom surface of package 24 and the strap loop 30. With some types of soft packages and at certain hish .

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tension levels, the slide cover 62 serves to prevent the loop 30 from pulling out of engagement from between the polyurethane pad 48 and the weld head 52. After tensioning, when the slide cover 62 is removed from between the package 24 and the loop 30 as will be described hereinafter, a certain amount of slack is thus present in the tightened loop. However, due to the elasticity of the plastic strap and due to the compressibility of the package 24, a tight loop is nevertheless achieved when the slide cover 62 i8 removed. Additionally, the slide cover .
` 10 62 can be made relatively thin (in the vertical diredtion as viewed in Figure 11) and can be made relatively narrow with respect to the package width (as viewed in the horizontal direction in Figure 2) to minimize the amount of slack formation.
Further, with certain types of packages (such as those having rather rigid and incompressible surfaces), and with low loop tension~, the sllde cover 62 Can be eli~inated ; altogether. ~his i8 because, at low tension levels, the strap ; loop has less of a tendency to be pulled out of engagement from between the polyurethane pad 48 and the weld head 52.
Further, the relative incompressibility of the package 24 would prevent the strap loop 30 from sinking into the package and pulling away from the polyurethane paa 48 and the weld ,.. . .
head 52.
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~il ; Although the tensioning process is illustrated in .
~ Figure 11 as occurring with the overlapped portions of the . ~ , ~' strap loop oriented in a plane parallel to the plane of the strap loop about the package, the loop 30 could be tensioned in other orientations. With very large packages and with ~.
~-- very small weld head diameters, it would be possible to ~- 30 insert the package into the expanded loop when the loop is ln _ . .. ,_,. ._ . . . , _ . , , _ .. _.. _, , .. . _ ,_ " _ .. , ,. ~ , . . .. . ... . . . .

the horizontal position as shown in Figure 3. Then the loop could be tensioned in that horizontal configuration. Though the diameter of the weld head 52 would create some amount of slack in the tensioned loop, with large compressible packages such slack would be negligible and would not affect the integ-rity of the tightened loop. If the strap loop was to be ten-sioned about the package in the horizontal direction, then the upper surface of shoulder 26 would advantageously be located at a lower elevation with respect to the weld head .
, ,,~ 10 52 and the strap transport zone 40 than is shown in,Figure 6.
;' The increased depth would accommodate placement and insertion ; of large packages within the horizontally oriented loop. Of ;, course, if the loop were to be tensioned in the horizontal ~ direction, provisions could also be made for automatically ,~ withdrawing the weld head 52 from between the strap and the ' ' , package after the tensioning proces~ has been completed.
, ~
', STRAP FEED AND TENSIONING MECHANISM
,' The strap is both fed and tensioned by one traction ,, wheel assembly. A traction wheel 68 and adjacent idler wheel ~ ,-.................................................................... .
70 are mounted for horizontal rotation in the strap transport ,~ ~one 40 as illustrated in Pigure 6. The idler wheel 70 i8 ~,'` preferably spring-biased against the traction wheel 68. The ,-i :
strap 36 is threaded in the guideways 42 and between the trac-,ion and idler wheel,s C8 and 70, respectively. Traction wheel 68 is mounted on a shaft 72 and is rotatably drivable in either ' ~ direction by an electric motor 76 which is connected to the , ,~ shaft'by a conventional drive belt 78. The motor can drive ' ~ the traction wheel 68 first clockwise (as viewed in Figure 6) . . ~
,, to feed the strap to form the loop and then counterclockwise : .
(as viewed in Figure 6) to tension the loop.

.
."' ~,' ' .

A bulk supply of strap is preferably wound on a conventional self-supporting spool (not shown) which can be placed near the apparatus 20 and which rotates to deliver strap in response to the feed force of the traction wheel pulling on the strap.
On the end of the shaft 72 opposite the traction wheel is an incremental rotation control unit 74 which signals the cup solenoid actuator 66 to lower cup 28 after the primary strap loop has been formed. Contro1 unit 74 is of a convention-al type which incorporates an electrically actuated clutch.
When the clutch is actuated, a cam member rotates with the ~haft 72 for one revolution, after which the clutch disengages the cam member from the shaft 72 and locks the cam against .,; .
further rotation. The cup solenoid actuator 66 i8 de-energized ; to lower the cup 28 by a l~mit switch provided in the control unit 74 and which is actuated by the rotating cam after one rotntion of the cam. In order that a single rotation of the ; traction wheel 68 causes the primary ~trap loop to be formed j~ within the cup 28 with the strap free end overlapping a por-; 20 tion of the loop, the diameter of the traction wheel 68 is larger than the diameter of the cup 28.
After formation of the primary strap loop in the t~ CUp 28, cup 28 is lowered away from the loop allowing the traction wheel 68 to expand the loop to a pxedetermined size.
Actually, since the cup 28 is lowered quite rapidly by the solenoid actuator 660 it is not necessary to terminate the strap feeding process while the cup 28 is being lowered. Thus, the strap is continuously fed without interruption until the desired expanded loop diameter is achieved.
- 30 The tensioning process is terminated when the desired level of loop tension is sensed. A tension sensing assembly '~ .

.
1~63501 is provided in the strap transport zone 40 and is illustrated in Figures 7, 9 and 12. A tension sensing wheel 83 is rotatably mounted about shaft 84 on arm 86. Arm 86 is pivotally mounted about shaft 88 to frame plate 90. Spring 92 is secured on one end to arm 86 and on the other end to an anchor 94 in the frame.
The spring 92 functions to pivot arm 86 counterclockwise about shaft 88 to bias the tension sensing wheel 83 against the side wall region 95 in strap transport zone guideway 42. The tension of spring 92 is adjustable and can be set to permit a given amount of spring extension at a predetermined strap tension . .
level. When the strap is under little or no tension, the strap length 36 is forced by the wheel against the side wall region 95 in guideway 42 as illustrated in Figures 7 and 9. ;
As the tension increases, the strap length 36 forces wheel 83 out from the wall region 95 because the tensioned strap 36 is drawn into a straight line between point 96 and point 97 in guideway 42. The present spring tension ls set 80 that the strap length 36 is prevented from forming a straight line between points 96 and 97 until the strap tension reaches the predeter-mined level. When the predetermined strap level is reached, the tension sensing wheel 83 is ~orced by the straight portion of strap length 36 to the position illustrated in Figure 12 where the arm 86 bears against contact arm 98 of a limit switch 100. Actuatic~ of the limit switch 100 in this manner opens the circuit of motor 76 to terminate the tensioning.
STRAP LOOP FRICTION FUSION MECHANISM
The method and mechanism for connecting the strap free end 38 to the overlapped portion of the length of strap 36 will now be described. If a plastic or plastic-coated met-al strap is used,a welded or friction-fused joint can be achieved by heating the overlapped region of the loop.

: ' .. . - ~ - .
" .. . : . ' ~ ~ ' , `- 1063501 In the preferred embodiment, the fusion heat is generated by rapidly moving the strap free end 38 against the overlapped portion of the length of strap 36 to qenerate heat by friction and effect interface melting therebetween. More particularly, this is accomplished by oscillating the weld head 52 with a relatively small angular rotation at a suffi-ciently high frequency. Weld head 52 is rotatably oscillated about the shaft 53 80 that the peripheral gripping surface 54, being engaged with a side of the strap free end 38, causes the strap free end 38 to be moved back and forth with respect to the stationary overlapped portion of the length of strap 36.
Typically, the frequency of oscillation is between about 50 and 100 hertz, the total amplitude of circumferential rotation of the gripping surface 54 is about 0.15 inch, and the oscillation ,,~ .
period lasts from between ~75 to 1.0 ~econd. In order to insure an adequate weld, the polyurethane pad 48 is pressed against tho overlapped portion of the longth of strap 36 with a higher force than is used during the tensioning process. Typically, a force of about 100 pounds is impressed against the strap during the friction-fusion process.
The weld head 52 is driven in the oscillatory mode by motor 80 and a connected oscillating drive transmission 82.
The motor 80, transmission 82, and control means (not shown) are well known and commerically used in present friction fusion ! ~ strapping machines. A description of such mechanisms can be found in the U.S. Patent to Ericsson, No. 3,586,572.
The friction fusion joint could be formed with a different type of anvil apparatus than illustrated. For example, pad 48 could be replaced with a cylindrical roller mounted for rotation about an axis parallel to the weld head ':

~' shaft 53 and having a roughened gripping surface. The rotation of the roller would allow for the feeding and tensioning of the strap. Then after the loop had been tensioned, the roller could be oscillated vertically (along its axis) by a suitable mechanism to vibrate the strap 36 against the free end 38 to create a fused joint.
After the friction-fusion joint has been com-pleted, the cup 28 is still maintained in the lowered position below the surface of shoulder 26 while the weld head 52 and the polyurethane pad 48 are maintained in com-pressive engagement on the strap loop so that the strap loop can be severed from a standing portion of the strap length 36 as will be next described in detail.
With metal strap, other types of ~oints could be created through the use of additional, conventional ~oint forming mechanisms (not illustrated). Such other ~oints may be, for example, of the independent seal type or of the interlocking slit type. Descriptions of such seals and sealing mechanisms can be found in the U.S. patents to Crosby, No. 2,710,435; to Crosby et al., No. 2,801,558; and to Beach, No. 3,303,541.
STRAP SEVERING MECHANISM
After the loop has been connected by the friction-fusion weld, the standing portion of the strap is severed from the loop by cutter 102 as best illustrated in Figures 6 and 9.
The cutter blade 102 is fixed in a slide block 104 which is slidably mounted for movement toward and away from strap 37 as best-shown in Figure 9. A cutter block 196 is provided to guide strap 36 to prevent the strap from deflect-- .

ing away from the cutter blade 102 as it is moved forward to sever the strap.
The Gutter blade 102 i8 moved through a linkage ,........................................................................... .
by a pneumatic cylinder actuator 109. As illustrated in Figure 6, link 108 is pivotally mounted about shaft 110 and is pivotally connected to arm 111 on one end and to cutter block 106 on the other end. Arm 111 i8 connected to the cutter air cylinder actuator 109 through a conven-tional cylinder piston rod (not shown). Pressurization of the cylinder actuator 109 forces the cylinder piston rod and arm 111 toward the cylinder actuator to pivot link 108 counterclockwise (as viewed in Figure 6) about shaft 110 thereby moving the cutter blade 102 forward to sever the .i , strap. The cylinder actuator is equipped with an internal ~pring to return the piston rod to tho extended position (and hence the cutter blade 102 to the retracted position) upon release of cylinder air pressure.
After the strap has been severed, the anvil slide 46 is moved away from the weld head 52 to retract the anvil 44 4nd the slide cover 62. With the anvil 44 retracted, the fused portion of the strap loop adjacent the weld head 52 is relieved from its 90 twist configuration with respect to the balance of the loop and lies flat along the bottom surface of the package. Since the slide cover 62 is also retracted, the tensioned strap loop tightens further, under influence of its elasticity, to fit tight around a , . I
portion of the surface of the package that was previously in contact with the slide cover 62. The strapped package - can then be removed from the apparatus.
PNEUMATIC ACTUATION SYSTEM
:
As previously described, the movement of cutter ..
blade 102 and anvil slide 46 is effected by pneumatic cylinder actuators 109 and 120, respectively. The actua- -tors are controlled by a pneumatic actuation system illus- -~
trated schematically in Figure 13.
The system is comprised of a supply manifold 124 supplying 90 p8i air to three pressure regulating valves 126, 128, and 130 downstream of which are three-way electri-cally operated solenoid valves 132, 134, and 136, respectively.
The solenoid valves admit air to a distribution manifold 137 for supplying the cylinder actuators 109 and 120. A check valve 138 prevents flow from solenoid valves 132 and 134 from pressurizing the cutter cylinder actuator 109. Cylinder actuator 109 can thus be pressurized only from solenoid valve 136 through a flow control valve 139.
Pressure regulating valves 126, 128, and 130 are set to control pressure to relative ~low, n nmedium~ n and ~high~ pressure levels, respectively, for purposes to be explained hereinafter. The solenoid valves 132, 134, and 136 each have three ports (labeled A, B, and C in Figure 13).
Exhaust port C is plugged in valves 134 and 136, but is unplugged to exhaust to atmosphere in valve 132. In the de-energized state, the solenoid valves are set to pass ,; .
flow through ports B and C ~except that port C is plugged on valves 134 and 136) and in the energized state the ~` valves pass flow through ports A and B.
~he actuation of the anvil cylinder actuator 120 will now be considered. When the primary strap loop is first formed in cup 28, the anvil 44 is moved forward to contact abutment surface 56 as illustrated in Figure 7.
- 30 With reference now to Figure 13 also, it can be seen that . .......................................................................... .
,:
:. . .

movement of anvil 44 to this position is accomplished by ~ sctuating air solenoid valve 132 to open ports A and B to ; allow a regulated low air pressure from pressure regulating .. . . valve 126 to act upon the piston in cylinder actuator 120 ~` and force anvil 44 against the cup abutment surface 56 with ; about 2 pounds of force. The 2 pounds of force i8 a nominal ~; amount that is used to insure that the anvil 44 i8 abutting the cup 28 to provide proper alignment and guiding of the ; strap free end 38 as it is fed forward into aperture 34 and between polyurethane pad 48 and weld head 52.
After the primary strap loop has been formed in cup 28, cup 28 is lowered to below the surface of shoulder 26. As cup 28 is being lowered, cup abutment surface 56 slides vertically downward along the front of anv~l 44. As j soon as cup 28 has cleared the bottom of anvil 44, anvil 44 is urged forward against the strap and weld head 52 by the

2 pounds of force that is still maintained by the anvil air 'I
cylinder actuator 120. The loop is expanded to a larger ~; dlameter with the anvil 44 maintaining the 2 pounds of force '':", ~ 20 on the strap. Next, after the expanded loop has been located around the package, a higher pressure must be applied to the overlapped portions to prevent the strap free end 38 from being drawn out of engagement with weld head 52, during the ! ~ tensioning step. Thus, at this point, solenoid valve 134 is energized to open port A to provide médium pressure air to anvil air cylinder actuator 120 to cause the anvil 44 to exert about 30 to 40 pounds on the strap against the weld ~. 4~ _ head 52. After the tensioning process has been completed, the solenoid valve 134 is de-energized to close port A.
, ;~ 30 However, since port C is plugged, the cylinder actuator 120 ~:

,. ' ~ 1063501 remains pressurized and the anvil 44 remains pressed against the strap loop.
During the next joint-forming step, the strap must be held with even more force against the weld head 52 as the weld head 52 is oscillated at high frequency to form the friction-fused joint. To accomplish this, the solenoid valve 136 is energized to open port A to admit higher pres-sure air to anvil air cylinder actuator 120 to force anvil 44 against the strap and weld head 52 with about 100 pounds Of force.
The cutter air cylinder actuator 109 is supplied with high pressure air from high pressure regulator 130 only through solenoid air valve 136 since check valve 138 pre-vents air from low and medium pressure regulators 126 and 128 from flowing into the cutter air cylinder actuator 109.
Note that ~olenoid air valve 136 admits air to both the anvil air cylinder actuator 120 and the cutter air cylinder ; ,:;
actuator 109 simultaneously. However, the action of the cutter air cylinder actuator 109 is delayed about one-half second while the high pressure air is admitted to the anvil air cylinder actuator 120 to hold the strap until comple-tion of the friction-fusion welding. After the weld is completed, the cutter air cylinder actuator 109 is permitted to move the cutter blade to sever the strap. This is accom-plished by the flow control valve 139 in the air supply line to cutter air cylinder actuator 109. The flow control valve .
139 p~ovides a controlled 810W rate of pressurization and, ~ acting through the cutter air cylinder actuator 109, moves !~.'',~ the cutter blade 102 forward so that it reaches the strap length 36 (Figure 12) just as the weld sequence is terminated.

, :

~ 1063501 After the cutter blade 102 has severed the strap and reached the full extent of its travel, solenoid valve 136 is de-energized to close port B and solenoid valve 132 i8 de-energized to close port A and open port c to exhaust air pregsure from both the cutter air cylinder actuator 109 ana the anvil air cylinder actuator 120. The internal spring return mechanisms in each of the cylinders causes anvil 44 and cutter blade 102 to return to the fully re-tracted positions.
ET~CTRICA~ CONTROL 8YSTEM
In order that the ~trap loop be properly formed, expanded, tensioned, friction-fused, and severed, the se-quence of operation must be appropriately controlled. The operation of the apparatus 20 of the present invention can be made to operate automatically and rapidly by means of a ~uitable electrical control sy~tem. A suitable oontrol sys-tem is illustrated $n the simplified oontrol block diagram i l of Figure 14. In the diagram, the neoessary intorlocking latching relays and switches are omittod. It is assumed that apparatus is at the beginning of a strapping cycle in a power-on ready mode with the strap threaded in the guide-ways 42 up to the cutter block 106. The cup 28 is in the . ~
rais-d po~ition by the energized solenoid actuator 66.
The solenoid valve 132 is energized to pressurize the anvil ~, cylinder actuator 120 to move the anvil 44 against the cup 28 ~a~ shown in Figure 7) with about 2 pounds of force.
`; The field coils of the traction wheel motor 76 are energized for motor operation in the direction to feed the strap into I
the cup 28.
A ~trap feed switch 143 is provided and is pre-' . .

ferably a foot-operated momentary contact type. When depressed, the feed switch 143 energizes the armature of the traction wheel motor 76 to turn the motor in the direc-tion to feed the strap. The feed switch 143 also actuates the incremental control unit 74 associated with the traction wheel shaft 72 to lower the cup 28 after the primary strap loop is formed. As the cup 28 is lowered, the motor is still rotating 80 that the strap continues feeding. As the cup reaches the lower position beneath the surface of the shoul-der 26, the anvil 44 is urged against the strap to force thestrap against the weld head 52 under the influence of the low pressure air being supplied to anvil cylinder actuator through the solenoid valve 132. The anvil 44 bears against the strap and the weld head 52 with about 2 pounds of force as the loop continues to expand. Release of the feed switch 143 stops the motor 76 and stops the strap feed. Repressing of the feed switch 143 continues the feeding of strap and expansion of the loop.
When the loop is of sufficient size, the operator releases the feed switch 143. Alternatively, if identically sized packages are being strapped on a production line basis the feeding of the strap and expansion of the loop ~; could be controlled by a timer. In any case, the operator next lifts the loop and places it over the package as illustrated in Figure 4.
A strap tension switch 148 is provided to reverse the motor 76 to tension the loop about the package. The tension switch 148 is preferably a foot-operated momentary contact type. The tension switch 148 is also connected to actuate the solenoid valve 134 to admit medium pressure air ``' ~ : .

~

to the anvil air cylinder actuator 120 to move the anvil 44 against the strap loop and the weld head 52 with about 40 pounds of force. This holds the strap free end 38 against the weld head 52 while the overlapping portion of the strap loop is allowed to slide against the anvil 44 as the loop is tensioned.
When the predetermined strap loop tension level (about 10 to 15 pounds on small packages) is reached, the tension sensing switch 100 is actuated to stop the motor 10 76 and rever~e the motor field coils for the next cycle operation in the feed direction. The tension sensing switch 100 also de-energizes the medium pressure solenoid valve 134 and energizes the solenoid valve 136 supplying the high pressure to the anvil cylinder actuator 120 and the cutter air cylinder actuator 109. This causes 1) the anvil actua-tor 120 to provide the high clamping force (approxlmately 100 pounds) required to hold the overlapped strap portion of the loop while the friction-fusion joint is made and 2) the cutter actuator 109 to move the cutter blade 102 to sever the strap after conclusion of the joint weld. The tension-sensing switch also actuates the weld motor 80 and the timer 152 which de-energizes the weld motor after the ; weld has been completed ~about 3/4 of a second to 1 second).
The timer 152 also de-energizes the solenoid valve 136 thereby blocking the high pressure air supply and de-ener-gizes the solenoid valve 132 to exhaust to atmosphere so that both the cutter air cylinder actuator 109 and the anvil air cylinder actuator 120 are returned by their internal spring mechanisms to the positions wherein the cutter 30 blade 120 and the anvil 44 are in the fully retracted posi-tions.

` 1063501 To set the apparatus for the next cycle, timer 152 also energizes two additional timers, 154 and 156.
Upon timing out, timer 154 energizes solenoid actuator 66 to raise cup 28 and timer 156 energizes solenoid valve 132 to move the anvil 44 forward to abut the cup 28. Timer 154 is set to provide a certain time period for removal of the strapped package before raising the cup 28. Timer 156 is set to provide a period longer than timer 154 to assure ; that the cup 28 will be in the raised position when the anvil 44 is moved forward.
.; ALTERNATE ENBODINENTS OF APPARATUS FOR EFFECTING THE METHOD
~j OF THE PRESENT INVENTION
,, ~ .
Formation of the strap loop with the apparatus illustrated in Figures 1 through 14 and heretofore described involves the use of a movable, circular guide ~cup 28).
The strap loop formation step of the method of the pres~nt invention can also be performed in a number of other ways.
In each of the embodiments, certain mechan~sms, though not always illustrated, will be understood to exi~t and function analogously to those mechanisms heretofore described for the embodiment illustrated in Figures 1-14.
~ ~ Exa~ples of such mechanisms are the strap tran~port zone .5:~ : guidos 42, the traction wheel 68, the idler wheel 70, and ; the cutter blade 71, as well as the necessary drive means, ' controls, and support structures. In all of the alternate :;:
embodiments an anvil and associated slide mechanism are ,~. :
provided ~as schematically illustrated and designated 144 and 146, 244 and 246, 344 and 346, 444 and 446, 544 and 546, and 644 and 646 in Figures 15-17; 18; 19 and 20; 21;
22-25; and 26-28, respectively). The anvil and slide in these alternate embodiments are understood to perform the .

.

same functions as the anvil 44 and slide 46 of the embodi-ment illustrated in Figures 1 through ~ and as heretofore described.
Figures 15 through 17 schematically illustrate another way of performing the step of forming a primary strap loop and expanding the strap loop to a larger dia-meter by use of an alternate, or second embodiment of a strap loop forming mechanism. The mechanism illustrated would be used in a strapping apparatus, such as the strap-ping apparatus 20 illustrated in Figures 1 through 14, and would be located in the strap loop forming area of the apparatus (the strap loop forming area of apparatus 20 i8 illustrated in Figures 8-9). Specifically, in place of the weld head 52, a loop forming wheel 112 is provided and functions as an inner guide for the length of strap 36 as the strap free end 38 is fed tangentially with the peri-meter of the wheel.
, Surrounding the wheel 112, and spaced from it, are a number of pivotable guide plates 114 which are spring-biased to a vertical position and provide a strap guide on the loop exterior side of the length of strap 36. Figure 17 shows one of the pivotable guide plates 114 biased to the vertical direction by an appropriate spring mechanism 116 and further shows a portion of the strap 36 adjacent , . ~
one side of the plate 114 as the strap is guided thereagainst.
The guide plates can be of varying size and number. In the embodiment illustrated, there are four guide plates forming a roughly polygonal shape, or more specifically, 4/6 of a hexagon. A fifth side of the hexagon is formed by a sta-tionary guide plate 115 and a sixth side of the hexagon is , -36-~ "

formed by a smooth-surfaced pad or anvil 144 which i8 movable towards and away from the wheel 112 by an appro-priate slide mechanism 146.
During the stage of initial loop formation, the ~A', strap free end 38 is fed into the strap loop forming area between the wheel 112 and the anvil 144 and is guided by .. ..
the wheel 112 and the guide plates 114 and 115 to form a loop therebetween. After the strap has been fed in a circle slightly greater than 2~ radians to form the loop with a portion overlapped by the strap free end 38, the anvil 144 . . .
i8 moved closer towards the wheel 112 to apply a predeter-mined amount of force against the overlapped portions of the strap loop between the anvil and the wheel 80 that the overlapped portions are lightly held together. The wheel 112 preferably has a rough peripheral surface for contacting a side of the strap free end 38. The strap is contlnued to be fed against the guide plate~ 114 and the ~trap free end ,. ...
38 is restrained, against the wheel 112, from further move-ment. With an appropriate choice of the strength of the spring 116 used to bias the guide plates 114 to the vertical position, the plates 114 will be forced to pivot outwardly ~.~,^ ,. ~ .
and down by the force of the expanding strap loop to assume the position shown in dashed lines in Figure 17. This will ~ permit the strap loop to expand to a larger size 30 as illus-'s, .
i~ trated in Figure 16.
., ~
When the loop has been expanded to the proper predetermined size, the strap feeding process i8 terminated.
Next, a package can be located over a portion of the loop and the loop can be twisted 90 (out of the plane of Figures 15 and 16) to place it around the package for subsequent , .
; .
,. ..
~ 37 ,,"' ; tensioning in the manner previously described for the embodiment illustrated in Figure 4. The wheel 112 may be relatively small, say between 1 and 2 inches in diameter, or may be much larger. Regardless, if plastic strap or plastic-coated metal strap is used, the wheel 112 can be oscillated with a small angular rotation at a sufficiently high frequency to form a friction-fused joint in the manner analogous to that described for the preferred embodiment .~; of the weld head 52 previously described with reference to Figures 1 through 14.
Severance of the strap loop from the trailing length of strap can be effected by a suitable strap sever-ing mechanism, not illustrated, such as the cutter blade 71 previously described for the preferred embodiment and j illustrated in Figure 7.
A third embodiment of the strap loop forming :; mechanism of an apparatus for strapping a package according : to the method of the present invention is illustrated in Figure 18 and is similar to the strap loop forming mech-,: " '" ' 20 anism of the first embodiment illustrated in Figures 1 through 14. A cup 228 is provided to receive the length of strap 36 and to guide the strap free end 38 on the inner periphery thereof to form a primary strap loop. A
weld head 252 is provided inside the cup 228 and has a . , .
lower guide flange 260 to maintain the plane of strap 36 at the proper elevation within the cup 228. An anvil 244 and ~;. movable slide mechanism 246 are illustrated schematically and function in a manner anælogous to the anvil 44 and : ~ movable slide mechanism 46 of the first embodiment illus-trated in Figures 1 through 14. However, in the case of ,~;, ~, ..

.~., . ~ .
~. -38- :-6350~ ~
;; ~ .., the embodiment illustrated in Pigure 18, the cup 228 is hinged, or pivotally mounted, on pin 262 for movement to a tilted position (shown in dashed lines in Figure 18) after the primary strap loop has been formed. This provides clearance around the periphery of the primary strap loop to allow subsequent expansion thereof. The cup 228 is moved to the tilted position by any suitable drive means or actu-ator means (not illustrated). With the strap having an appropriate combination of thickness, width, and flexibility, any movement or tilting of the cup is not even necessarily required. That is, the cup, with a properly shaped wall, could remain stationary after formation of the primary strap loop. Then continued feeding of the strap into the cup will cause the strap to buckle out of the cup 80 that it can expand to a larger size.
Figures 19 and 20 illustrate a fourth ~mbodiment of the strap loop forming mechanism of an apparatus for strapping a package according to the method of the present inv ntion. In this embodiment, a strap loop is formed in a plane perpendicular to a package support surface 322 on a strapping apparatus. Initially, the package 324 is placed upon the package support surface 322 adjacent the loop forming area. A length of strap 36 is then fed between, .
and guided by, two axially aligned adjacent guide rings 326 and 328. The guide rings 326 and 328 are pivotally mounted on pins 330 and 332 respectively, which are mounted ~` in recessed channels 334 and 336, respectively. The guide p~ ~
rings 326 and 328 can thus be rotated 90 degrees to a position below, and parallel to, the package support sur-face 322. To this end, guide ring cavities 338 and 340 . ,: .
.....
~''.' ' .

.

are provided to receive the guide rings 326 and 328, respectively. The strap 36 can be fed into a slot (not shown) between the guide rings 326 and 328 by an appropriate traction wheel mechanism.
In a manner analogous to that described for the embodiment illustrated in Figures 1 through 14, a plastic strap or plastic coated metal strap can be formed into a primary strap loop and then gripped between a weld head 352 and an anvil 344 for the subsequent loop expansion, loop tensioning, and friction fusion steps. In Figure 19, the anvil 344 is schematically illustrated as being movable towards and away from the strap 36 and weld head 352 by slide mechanism 346 and the weld head 352 i8 shown mounted on shaft 353 and driven by an appropriate drive means or motor 355.
By appropriate control means, the length of strap l 36 i~ fed between the guide rings 326 and 328 until a pri-;j mary strap loop is formed with the strap free end 38 over-lapping a portion of the loop. At this point, the anvil 344 is urged against the overlapping strap portions and the guide rings are moved, by a suitable means, to the horizontal .
position below the package support surface 322 to provide i. ... .
clearance around the periphery of the loop. The loop is then expanded by continued feeding of the length of strap until the desired larger diameter is reached. The package is then moved into the loop and the loop is subsequently tightened, tensioned, and severed in a manner similar to that described for the embodiment illustrated in Figures 1 through 14. However, with the apparatus illustrated in Figures 19 and 20, the loop does not have to be twisted ~

., :

~063SO~

90 degrees to be placed around the package since the loop is formed initially in the plane perpendicular to the pack-age support surface 322 and since the package 324 can be placed therein without requiring the loop to be twisted in any manner.
When the loop is tensioned about the package 324, the small weld head 352 is necessarily located between the package and the strap loop which causes the loop to be slightly larger than the periphery of the package. After the loop has been tensioned, friction-fused ~or the over-lapped ends otherwise suitably ~oined), and severed from the trailing length of strap, the weld head 352 must be , . . .
removed from between the package and the strap loop. This can be accomplished by moving the combined assembly of weld head 352, shaft 353 and motor 355 away from the package (in a direotion to the right as viewed in Figure 19) by appro-priate mechanisms (whlch are not illustrated). With very large packages and with very small weld head diameters, ... .
the creation of a slightly larger diameter loop about the package resulting from the weld head being disposed between th loop and the package is negligible. Further, if the large package was slightly resilient, the package would ;~ expand slightly to a larger diameter (and the strap itself would contract to a slightly smaller diameter) to effect a tight loop about the package.
~ Figure 21 illustrates a fifth way of performing fy~,,, ?~
~, the step of forming a primary strap loop and expanding the ,i~ - strap loop to a larger diameter. The mechanism illustrated in Figure 21 would be used in a strapping apparatus, such as the strapping apparatus 20 illustrated in Figures 1 ~.~
,.
~ ~ .

~ 0~;3501 through i4, and would be located in the strap loop forming area of the apparatus (the strap loop forming area of apparatus 20 is illustrated in Figures 8-10). Specifically, in place of the guide cup 28 and the weld head 52 in apparatus 20, there is provided a flexible guide band 428 and a strap free end stop block 452, respectively. Opposite the stop block 452 is an anvil 444 which is movable toward and away from the stop block 452 by a slide mechanism 446.
The length of strap 36 is introduced to the inner periphery of the flexible guide band 428 between the anvil 444 and stop block 452. The strap free end 38 18 guided in a circle by the inner periphery of the flexible guide band 428, and after traveling in a circle for slightly greater than 2 radians, impinges upon the stop block 4æ thus forming a primary strap loop with a portion of the loop overlapped by the strap free end 38.
The flexible guide band 428 can be of any suit-, ably flexible material such as polyethylene or rubber, or even thln metal. In the loop forming position, the band 428 extends from an anchor point 454 in a circular locus with a free end 455 in abutment with the anvil 444. On the free end 455 of the flexible guide band i8 a guide pin or prong 457 which projects from the bottom of the flexible guide band 428 and into an arcuate slot or track 458 in the shoulder surface 26 of the apparatus. As illustrated in Figure 21, the shape of the track 458 is an involute of the circle formed by the flexible guide band 428 when the band is in the position illustrated in Figure 21 for forming the primary strap loop. After the primary strap loop has been formed, the free end 455 of the band 428 is ,' .
; ' ~0 6 ~ ~

moved in the locus of the track 458. To this end, by appropriate drive means not illustrated, the pin 457 on the free end 455 of the band 428 is driven in the track 458 to point B so that the flexible guide band 428 assumes a substantially straight line orientation illustrated by dashed lines and labeled 428'. In the straight line orien-tation, the flexible guide band 428' is thus spaced away from the formed primary strap loop to provide clearance ; about the periphery of the loop. Next, the anvil 444 is moved closer towards the loop to apply a relatively small force against the overlapped portions of the strap loop to restrain the strap free end 38 from disengaging from the stop block 452. Subsequently, by appropriate feed drive means, the length of strap 36 can continue to be fed to j expand the loop to the desired larger diameter. A package ".. .. .
can then be placed over a portion of the loop and the loop can be twisted about the package. The loop can then be ten~ioned and tightened about the package in a manner simi-`'' lar to that previousl~ described for the embodiment illus-trated in Figures 1 through 14. The overlapping portions ~i of the strap loop can be joined by appropriate means, ~1 ' ;'; such as by a friction-fusion, application of an independent ~,;. ., ' seal, or formation of an interlocking slit joint. Creation of a friction-fusion joint would require the stop block 452 i, to be oscillated or vibrated sufficiently rapidly to generate heat by friction and effect interface melting therebetween.
Mechanisms for applying an independent seal or for forming -i an interlocking slit joint to metal strap would be of a r conventional nature and associated with anvil 444 and stop block 452 as may be necessary or desired.

`
~ .~ .. .. .

~063501 Figures 22 through 25 illustrate another way of performing the step for forming a primary strap loop and expanding the strap loop to a larger diameter by use of a sixth embodiment of a strap loop forming mechanism.
The mechanism illustrated would be used in a strapping apparatus, such as the strapping apparatus 20 illustrated in Figures 1 through 14and previously described. The strap loop forming mechanism would be located in the strap loop forming area of the apparatus (the strap loop forming area of apparatus 20 is illustrated in Figures 8-10).
In this sixth embodiment, a strap guide is not required. Instead, a wheel 552 is provided ~in place of the weld head 52 of the first embodiment illustrated in Figures 8-10) which has a slot 554 for receiving the strap free end 38 of a length of strap 36. As the strap is fed by appropriate traction wheel feed means ~not illustrated), ,; the strap free end 38 enters the slot 554, abuts the end of the slot in the wheel 552 and the wheel is rotated (counter-clockwise as viewed in Figures 22 to 24). The length of strap 36 is fed until the wheel 552 has rotated slightly greater than 2~ radians so that a primary strap loop is formed with a portion of the loop overlapped by the free i end 38. After the primary strap loop has been formed, the wheel 552 can be locked again6t further rotation whlle the strap length 36 is continued to be fed. An anvil 544 i8 provided adjacent the wheel 552 and is movable toward and away from the wheel by a slide mechanism 546 (schematically illustrated in Figures 22 through 25). The anvil 544 is brought into contact with the exterior side of the length of strap 36 in the area of the overlapped portion of the ',~ ' "
,.................................. . ~ :
'' . " ' -.' : ' ' . - ,.,' ' ' ' ~: , - - . , ~ . , .

~063501 . .
loop to restrain the strap against movement away from wheel 552 at that point. With the wheel 552 prevented from rotating, the primary strap loop expands from around ~ the periphery of the wheel 552 to form a loop 30 of any -~ desired larger size as illustrated in Figure 24.
With a relatively small wheel 552 and a relatively ~i large package 24, the package 24 can be inserted into the expanded loop as shown in Figure 25. By means previously described for the other embodiments, the loop can then be ~;, 10 tensioned about the package. Subseguently, the wheel 552 '1'''' ':' ;- ~ could also function analogously to the weld head 52, des-crlbed for the embodiment illustrated in Figures 1 through ; 14, by producing a friction-fused joint. Following formation , ~, ~ of the friction-fused joint, the wheel 552 is withdrawn from ; betweon the package and the loop.
, . ...................................................................... .
Alternatively, instoad of inserting the package 24 into the expanded loop as illustrated in Figure 25, the expanded loop could be first twisted 90 degrees ~out of the plane of Figure 25) and the package could then be inserted into the loop above the wheel 552 and anvil 544. Such a 90 degree twist orientation of the loop is identical to that effected in the process step performed by the previously described preferred embodiment and illustrated in Figure 11.
Further, with metal strap, the overlapping por-tions of the strap loop could be joined by conventional independent seals or interlocking slit joints, The mech-.,;
~ anisms for effecting such conventional joints are not .
~ illustrated in Figure 25 but could be located adjacent the s;i; ~ wheel 552 and anvil 544 around the overlapped portion of ~ 30 the strap loop.
~ .
~ . , .

~ -45-,~ ' ;' r - `

~063s0~
A seventh.embodiment of a strap loop forming mechanism i8 illuætrated in Figures 26 through 28. The mechanism illustrated therein would be used in a strapping apparatus, such as the strapping apparatus 20 illustrated in Figures 1 through 14, and would be located in the strap loop forming area of the apparatus (the strap loop forming area of apparatus 20 is illustrated in Figures 8-10).
A substsntially circular guide 628 is provided in the surface of the apparatus for receiving the length of strap 36. In place of a weld head (such as weld head 52 illustrated in Figures 6 through 10) a stop block 652 i8 provided near the periphory of the circular guide 628.
Opposite the stop block 652 is an anvil 644 which is mova-~le toward ~nd away from tho stop block by a slide mechanism 646 which is schematically lllustratod in the Plgures 26 :~
and 27.
,i . .
,: Initially, when the length of strap 36 is fed into the guide 628, the strap free end 38 passes between the stop block 652 and the anvil 644 which has been spaced 20 away from the stop block 652 to allow passage therebetween.
The strap free end 38 is then guided around the periphery of the guide 628 until it has completed a circular motion of a slightly greater than 2~ radians 80 that a strap loop is formed with a portion of the loop being overlapped by strap free end 38 and 80 that the strap free end 38 has . .~ .
impinged upon stop block 652~
Next, the anvil 644 is moved to press against the overlapped portion of the loop with a relatively small ~ force and the formed primary strap loop is partially .,.~ 30 lifted out of the guide 628 to allow expansion of the loop.
.~,.
~ . .

,~ --46--f~

To this end, a liPt lever 650 is provided below the formed primary strap loop and the bottom of the guide 628. Lift lever 650 is pivotally mounted on pin 651 below guide 628 ; and is pivotally connected on one end to rod 657 which is ,, , secured to actuator 659. Actuator 659 moves rod 657 in a vertical reciprocal tion as viewed in Figure 27 to lower and raise, respectively, the lift finger 650.
When the lift finger 650 has been raised to the ; ~ position shown in Figure 27, the length of strap 36 can continue to be fed 80 that the loop 30 expands to any desired larger diameter as illustrated in Figure 28. A
package to be strapped is then placed over the stop guide /~ block 652 and anvil 644 and the expanded loop is twisted upwardly and around the package in a manner analogous to that for the preferred embodiment illustrated in Figure 11.
~,.....
; Subseguently, the loop can be tew ion~d by a suitable trao-tion wheel mechanism, such as that described for the pre-,;,.:
ferred embodiment of the apparatus 20 illustrated in Figures 1 through 14.
After tensioning, a conventional independent seal or slit joint can be applied to the overlapped portion of , . ~ .
; i the strap loop by mechanisms not illustrated. Alternately, ~ ~ the stop block 652 could be rapidly oscillated or vibrated . , to effect a friction fusion joint on a plastic or plastic-coated metal strap. Instead of a stop block 652, a weld head similar to the weld head 52 illustrated in Figures 6-10, could be provided. It is not necessary that the strap free " ~ .
~ end 38 abut a stop block or similar member upon completion . ~
;~ of forming the primary strap loop. This is because the strap feeding can be governed by suitable automatic rotation ~.

.

:

indexing controls to terminate the feeding of the length of strap 36 after the primary strap loop has been created with the desired amount of overlap.
An eighth embodiment of a strap loop forming mechanism is illustrated in Figures 29 and 30. The mech-; anism illustrated therein would be u~ed in a strapping apparatus, such as the strapping apparatus 20 illustrated in Figures 1 through 14, and would be located in the strap loop forming area of the apparatus (the strap loop forming area of apparatus 20 is illustrated in Figures 8-10). This eighth embodiment is somewhat similar to the fourth embodi-ment illustrated in Figures 19 and 20 and described above.
In this eighth embodiment, strap guide rings 726 and 728 are pivotally mounted for movement into a cavity 738 below the package support surface 722. However, the gulde rings 726 and 728 pivot about axes 727 and 729 respectively, which are perpendicular to the plane of the primary loop fonmation ; whereas the guide rings 326 and 328 of the fourth embodi-ment pivot about axes that are parallel to the plane of primary strap loop formation. The guide rings 726 and 728 each have identical cross sections that are substantially H-shaped. As illustrated for guide ring 728 in Figure 21, the H-shaped cross section provides an interior channel comprising sidewalls 731 and 733 and a perpendicular arcuate guide wall 735, all of which function to contain and guide the strap as the primary loop is being formed.
!' i . .
Unlike the fourth embodiment, the eighth embodi-ment does not have a weld head mounted within the central portion of the guide rings. Rather, an anvil 744 is pivot-ally mounted about shaft 745 and has 1) a top surface flush ':

: 1063501 . ' : .
with the package support surface 722 and 2) a strap bearing surface opposite, and facing, a combination feed/tension/
weld head wheel 752. After completion of the strapping process, the anvil 744 can be pivoted out from between the -package and the strap loop by an appropriate actuator and linkage mechanism 747.
The strap 36 is threaded between the anvil 744 and feed/tension/weld head wheel 752 and is fed by rotation of the wheel 752 in a clockwise direction (as viewed in ~.
Figure 29) around the inner periphery of the vertically oriented guide rings 726 and 728 until the strap free end 38 overlaps a portion of the loop. In order for the loop to be expanded, the guide rinqs 726 and 728 mu~t be pivoted about axes 727 and 729 respectively, to the lower position illustrated by dashed lines in Figure 29. This, of course, provides an unobstructed expansion area around the peri-meter of the primary loop to allow expansion thereof to a predetermined larger diameter. The pivotal movement of the guide rings 726 and 728 is effected by an appropriate actuator mechanism such as an electric solenoid or air-operated cylinder actuator 765 connected to linkage members 766, 767, and 769.
As illustrated in Figure 30, wheel 752 is mounted on shaft 753 to motor 755. Motor 755 is mounted on carriage .
~ 757 which can move the motor, shaft, and wheel in a vertical - direction by suitable drive means ~not shown). The weld head 752 is generally cylindrical and presents a peripheral strap gripping surface. As the primary loop is being formed, and during subsequent operations, the weld head 752 is aligned with the strap 36 as illustrated in Figure 30. By appropriate movement of the carriage 757, the weld head 752 can be impressed upon strap 36 so that the strap free end 38 is maintained in frictional engagement with anvil 744 while strap length 36 can continue to be fed forward into the guide rings 726 and 728, sliding against the adjacent strap free end 38, to expand the loop.
After the loop has been expanded, the rotation of wheel 752 is reversed to tension the loop about a package that has been inserted therein. If necessary, by appro-priate upward movement of the carriage 757, a higher force - can be applied to the overlapping strap lengths 36 and 38 by the wheel 752 during the tensioning process to hold the strap free end 38 in place.
After the tensioning is complete, a connection can be formed between the strap free end 38 and the overlapped strap length 36, such as by friction fusion wherein the wheel 752 is rapidly oscillated or vibrated to form a fric-j tion fusion joint on plastic or plastic-coated metal strap.
Alternatively, a friction fusion joint could be formed by rapidly vibrating the anvil 744. In either ca~e, the fre-quency and amplitude parameters relating to the formation of such a joint would be the same as has been described above under the section entitled ~STRAP LOOP FRICTION
FUSION MECHANISM. n s It i8 posgible to form a loop that has an over-lapping joint area different than those discussed so far.
Figure 31 schematically illustrates such a formed primary strap loop. A length of strap 36 is fed in a closed path ; to form a primary strap loop with a portion of the strap loop overlapped by the strap free end 38. Note that in , .. . .

... : : . : . . .

.~ ' 1063S01 this loop, the surface of the strap which is on the "inside~
of the loop is maintained in an orientation such that, in - the region of the overlap 812, the "inside~ surfaces of the ~ strap are in a facing relationship. The loop can be thus ~,, '~$ ~. formed by hand or mechanically (which can include feeding the ~trap 36 in a closed path to form this type of loop).
Following formation of the primary strap loop, the strap free end 38 i8 restrained from vement while the standing length of strap is fed to expand the loop to a predetermined size. Then a package can be inserted into the expanded loop, after which the loop is tensioned i~bout the package. The ,:
strap free end 38 is then joined, by appropriate means, to the overlapped portion of the strap length 36 to form a connection and secure the loop about the package.
During expansion of the loop, the strap free end 38 may be restrained from movement by pressing it, with a first member 814, against the overlapped portion to the ., ~
i strap 36 in the region of overlap 812. A second member 816, opposite the first member and presenting relatively less sliding resistance to strap movement, is pressed against ,,,,~ , ;~ the strap 36. Specifically, members 814 and 816 could, for example, comprise respectively, a weld head and an anvil, similar to weld head 52 and anvil 44 described for the pre-' k~ ferred embodiment previou~ly described and illustrated in Figures 1 through 14. It should be noted that once a loop such as illustrated in Figure 31 has been expanded, the overlapping portions can be joined by any appropriate means, including friction fusion, formation of interlocking slits, or application of an independent seal. Most impor-tantly, the joint can be formed, as by members 814 and 816 ~.
`.~

: ` :
1063501 ~
(or other members located adjacent thereto), without requiring that any member, or portion thereof, be placed inside the loop between the strap and the package. This has the advantage of increasing residual tension in the loop since the loop when tensioned, can be drawn tighter around the package. Further, it should be noted that the strap loop does not necessarily have to be "twisted"
to be placed about the package. The loop can be formed and expanded in one plane and the package then moved per-pendicular to that plane and into the loop.
The method of the present inven~ion can be advantageously used with compressible articles, bundles, or bales. In one case, preformed metal or plastic strap i~
segments, ~e.g., bale ties) could be stacked and loaded in a magazine of an appropriate apparatus for sequential feeding (one at a time) to 1) form an lnitial primary . '!
strap loop and 2) subsequently form an expanded loop.
Thi~ could be accompll~hed, in part, with apparatus simi-lar to those described above for the various illustrated embodiments. After the loop ha~ been expanded to a larger predetermined size, the overlapping ends of the loop could be joined by any appropriate means. Next, a compressed bale could be inserted into the strap loop and allowed to expand against the strap, thus forming a tied bale.
Alternatively, the formed and joined strap loop could be removed from the strap loop forming apparatus and placed ; ~: . i i . "1 around a compressed bale which is then allowed to expand to form a tied bundle.
Instead of using separate preformed strap segments, a compressed bale could be tied with a loop formed from a .... . . ~ .
. . - . ~ .

` - 1063501 continuous length of strap. Apparatus similar to that illustrated in Figure~ 1 through 14 could be used to form an expanded loop. But, instead of tensioning the loop about the bale, just the joint could be formed in the loop. Then the compressed bale could be placed in the loop and allowed to expand to form the tied bale. ~lternatively, the formed and joined loop could be removed from the apparatus and then placed around the bale.
With respect to bindinq a compressed bale as de~cribed above, it is important to note that tension need not nece~sarily be drawn on the expanded strap loop. With certain types of bales, it can be sufficient to allow the compressed bale to expand lnto binding engagemont with a formed and ~oined strap loop.
~i From the foregoing, it will be obsorvod that ,, .
numorous variations and modifications may be effected without doparting from the true spirit and scope of the novel conc-pt of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims i all such modifications as fall within the scope of the ~. .
l ~ claims.

,:
.. ..

Claims (33)

1. A method of forming a strap loop and secur-ing it about a package comprising:
feeding a length of strap in a closed path to form a primary strap loop with a portion of the strap loop overlapped by the free end of the strap; restraining said free end of the strap from further movement while continu-ing to feed the standing length of the strap to expand the loop to a predetermined size; effecting relative movement between said package and the expanded loop to locate the expanded loop about said package; tensioning said length of strap to tighten the loop about said package while con-tinuing to restrain said strap free end from further move-ment; and joining said free end of the strap and an adja-cent overlapped portion of the loop.

2. The method of claim 1 wherein the step of forming a primary strap loop includes guiding a portion of one edge of the length of strap in a plane parallel to the plane of the formed primary strap loop.

3. The method of claim 1 wherein the step of forming a primary strap loop includes guiding a portion of each of the two edges of the length of strap in sepa-rate planes parallel to the plane of the formed primary strap loop.

4. The method of claim 1 wherein the step of forming a primary strap loop includes providing a generally circular guide on the exterior periphery of said primary strap loop to guide said free end of the strap.

5. The method of claim 4 including the addi-tional step of effecting relative movement between said generally circular guide and said primary strap loop to provide clearance around the periphery of said primary strap loop to permit expansion of the loop to said prede-termined size.

6. The method of claim 1 wherein the step of forming a primary strap loop includes feeding a length of strap against walls of a guide structure wherein each wall forms a side of a polygon.

7. The method of claim 6 including the addi-tional step of pivoting at least one of said walls about an edge parallel to the plane of the primary strap loop to provide clearance around a portion of the periphery of said loop to permit expansion of the loop to said predeter-mined size.

8. The method of claim 1 wherein the step of forming a primary strap loop includes feeding a length of strap between two axially aligned adjacent guide rings.

9. The method of claim 8 including the additional step of pivoting each guide ring away from said primary strap loop to provide clearance around the periphery of said loop to permit expansion of the loop to said prede-termined size.

10. The method of claim 1 wherein the step of forming a primary strap loop includes feeding a length of strap on the inside of a flexible member which is main-tained in an arcuate configuration.

11. The method of claim 10 including the addi-tional step of pulling one end of said flexible member increasingly away from the center of said primary strap loop whereby said flexible member is peeled away from said loop to provide clearance around the periphery of said loop to permit expansion of the loop to said predeter-mined size.

12. The method of claim 1 wherein the step of forming a primary strap loop includes holding the free end of a length of strap and moving said free end in a closed path to orient one strap side on the free end adjacent and facing the opposite strap side on said overlapped portion.

13. The method of claim 12 wherein the step of holding the free end of a length of strap includes re-straining said free end in a slot on a rotatable holding member.

14. The method of claim 13 wherein the step of moving said strap end in a closed path includes rotating said holding member greater than 2.pi. radius.

15. The method of claim 1 wherein the step of effecting relative movement between said package and the expanded loop includes the steps of first restraining an area of the expanded loop and then twisting the balance of the loop about said area and out of the plane of loop formation to locate the loop about said package.

16. The method of claim 15 wherein the step of first restraining the loop includes pressing said free end and an overlapped portion of the loop between a rough-surfaced member contacting a side of said free end and a smooth-surfaced member contacting a side of the overlapped portion of the strap loop.

17. A method of forming a strap loop and secur-ing it about a package comprising: feeding a length of strap into a strap guide; guiding the free end of the strap in said strap guide in a closed arcuate path to form a pri-mary loop with a portion of said primary loop overlapped by said free end of the strap; gripping said free end of the strap to prevent further movement of said free end;
effecting relative movement between said primary loop and said strap guide to provide clearance around the periphery of said primary loop while continuing to feed the standing portion of strap to expand the loop to a predetermined dia-meter; inserting a package in the expanded loop; drawing the loop tight around said package while continuing to grip said strap free end to prevent further movement:
friction welding said free end of the strap to an adjacent overlapped portion of the loop; and severing said standing portion of the strap from the tightened and welded loop.

18. A method of forming a strap loop and secur-ing it about a package comprising:
forming a primary strap loop with a portion of the strap loop overlapped by the free end of the strap;
restraining said free end of the strap from further move-ment while feeding the standing length of the strap to expand the loop to a predetermined size; effecting rela-tive movement between said package and the expanded loop to locate the expanded loop about said package while con-tinuing to restrain said strap free end from further move-ment, and joining said free end of the strap and an adja-cent overlapped portion of the loop.

19. An apparatus for forming, tensioning and securing a strap loop about a package, said apparatus comprising:
means for forming 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 and while effecting relative movement between said package and the expanded loop to locate the expanded loop about said package;
means for tensioning the strap to tighten the loop about said package while said strap free end restrain-ing means continues to restrain movement of said strap free end; and means for joining said free end of the strap and an adjacent overlapped portion of the loop.

20. The apparatus in accordance with claim 19 in which said means for forming a primary loop includes a circular band member having a slot, said band member being positioned to receive said length of a strap through said slot and being designed to guide the strap along the inner surface of the band to form said primary strap loop.

21. The apparatus in accordance with claim 20 in which said slot is open to one edge of said band member and including means for moving said band member between a first position wherein said primary strap loop is formed and a second position parallel to, and spaced away from, said first position to allow said primary strap loop to be expanded to said predetermined size out of contact with said band member.

22. The apparatus in accordance with claim 19 in which said means for restraining said free end of the strap comprises a rough-surfaced member adapted for bear-ing against a side of said free end to engage said free end between said rough-surfaced member and an adjacent over-lapped portion of the loop while the standing length of the strap is fed to expand the loop.

23. An apparatus for forming, tensioning, and securing a strap loop about a package, said apparatus comprising:
a frame having means for supporting a length of strap;
means for feeding a length of strap;
guide means for receiving a free end of said length of strap and for guiding said free end in a path to form a primary strap loop with a portion of the strap loop overlapped by said free end;
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 and while effecting relative movement between said package and the expanded loop to locate the expanded loop about said package means for tensioning the strap to tighten the loop about said package while said strap free end restrain-ing means continues to restrain movement of said strap free end; and means for joining said free end of the strap and an adjacent overlapped portion of the loop.

24. The apparatus in accordance with claim 23 in which said guide means is a hollow, substantially cy-lindrical member having a slot for passing said length of strap from the exterior of said cylindrical member to the interior of said cylindrical member.

25. The apparatus in accordance with claim 24 in which said slot is open to one end of said cylindrical member and including means for moving said cylindrical member 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 ex-panded to said predetermined size out of contact with said cylindrical member.

26. The apparatus in accordance with claim 23 in which said strap is one of non-metallic and metallic with a non-metallic coating and in which said means for forming a connection comprises a rough-surfaced gripping member rotatably mounted on said frame, means for effecting relative movement between said anvil and said gripping member to compress said strap free end and an adjacent overlapped portion of the loop therebetween and to place said strap free end and the adjacent overlapped portion of the loop in frictional engagement, and means for oscil-lating said gripping member to produce bodily sliding frictional movement of said strap free end against the adjacent overlapped portion of the loop to effect interface melting therebetween, whereby said strap free end is fused to the adjacent overlapped portion of the loop.

27. The apparatus in accordance with claim 23 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.

28. The apparatus in accordance with claim 27 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.

29. The apparatus in accordance with claim 28 in which said strap edge locator means comprises a flange on one end of said rough-surfaced member.

30. 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 appa-ratus 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 sur-face;
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 di-rection 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 sur-face 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 trans-port 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 pri-mary strap loop with a portion of the strap loop overlapped by the free end of the strap, said guide being movable between a first position in alignment with said strap trans-port 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 and wherein said primary strap loop can be located about said package and subse-quently tensioned with said free end of the strap still pressed between said weld head gripping surface and the adjacent overlapped portion of the loop by the 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 over-lapped portion of the loop; and cutter means for severing the standing portion of the length of strap from the tightened and fused loop.

31. The apparatus in accordance with claim 30 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 forma-tion of said primary strap loop in said guide.

32. The apparatus in accordance with claim 31 in which said traction wheel is secured to a shaft and in which said control means includes a clutch member engage-able with said shaft.

33. The apparatus in accordance with claim 30 in which said means for moving said anvil includes an air operated piston and cylinder actuator and in which said apparatus further includes 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.