US3411551A

US3411551A - Manual strapping tool

Info

Publication number: US3411551A
Application number: US440462A
Authority: US
Inventors: Robert F Plattner
Original assignee: Interlake Steel Corp
Current assignee: Interlake Steel Corp
Priority date: 1965-03-17
Filing date: 1965-03-17
Publication date: 1968-11-19
Anticipated expiration: 1985-11-19

Description

Nov. 19, 1968 R, F. PLATTNER 3,411,551

MANUAL STRAP? I NG TOOL Filed March 17, 1965 v I 6 Sheds-Sheet 1 gawrz 3 651172 1968 R. F. PLATTNER 3,411,551

MANUAL STRAPPING TOOL Filed March 17, 1965 6 Sheets-Sheet 2 Nov. 19, 1968 R. F PLATTNER MANUAL STRAPPING TOOL 6 Sheets-Sheet 5 Filed March 17, 196

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Filed March 17, 1965 Nov. 19, 1968 R. F. PLATTNER 3,411,551

MANUAL STRAPPING TOOL Filed March 17, 1965 6 Sheets-Sheet 6 United States Patent 3,411,551 MANUAL STRAPPING TOOL Robert F. Plattner, Chicago Heights, 11]., assignor to Interlake Steel Corporation, Chicago, 111., a corporation of New York Filed Mar. 17, 1965, Ser. No. 440,462 18 Claims. (Cl. 140--93.4)

ABSTRACT OF THE DISCLOSURE A strapping tool for tensioning overlapping ends of a strap loop'encircling an object having mechanism permitting single handle operation of both strap tensioning and joint forming mechanisms thereon.

This invention relates to a manual strapping tool of the type employed for crimping a seal about overlapping ends of a strap loop and more particularly is concerned with a manual strapping tool that is of simplified construction and that is easy to operate through a full operating sequence.

Some of the principal steps in the operating sequence which require manual manipulation of the tool are: positioning the tool in engaging relation upon the overlap ping strap ends after a strap has been looped about a package or other object that is to be tied; tensioning the strap loop by repeatedly ratcheting a rotary gripper wheel; applying and crimping a seal about the overlapping strap ends after tensioning is completed; feeding another seal for use in the next joint sealing application; and releasing the tool after the first seal is completed.

In the prior art, tools for accomplishing this sequence have involved excessive complexity that encumbered both the construction and the operation, and the present invention has for its principal object the provision of a tool for manual operation through such a sequence without need for extraneous control mechanism.

Another object is the provision of a tool for manual operation through such a sequence wherein a single actuating arm sequentially controls actuation of the mechanisms that perform the various functions of a complete strapping cycle.

A further object of the invention is the provision of a manually operated tool arranged to enable a single actuating arm to be moved through a full operating sequencel of a complete strapping cycle while requiring only oriehand of the operator, with the other hand of the opiia'tor being free to assist in orienting the package or in orienting the strap loop or in performing similar functions incident to a strapping-operation.

It is an important object of the invention to provide an improved mechanism in combination with a manually operated strapping tool of a type having a driving pawl carried on and swingable with an auxiliary frame under the control of an actuating arm for ratcheting a rotary tensioning wheel device in a strap tensioning direction, with the improved mechanism including a pawl control element mounted in the auxiliary frame and automatically shiftable to disengage the drive pawl at the end of the seal forming action and with the pawl thereafter being automatically resettable as the actuating arm is swung to a position .for releasing the tool from the previously sealed strap ends.

Still another object of the invention is the provision of a manually operated strapping tool incorporating a rotary adjustable drive pawl equipped with an externally accessible release pin to enable disengagement of the drive pawl by direct manual manipulation whenever required.

In tools of the type herein referred to, tensioning of the strap loop by means of a rotary tensioning wheel is accomplished in certain cases by employing a plug adjustably mounted within the frame portion over which the strap passes as it is tensioned. The overlapping strap ends pass between the plug and the rotary tensioning wheel. Both the plug and the wheel have sharp teeth which bite into the strap. The teeth on the plug retain the lower strap end and keep it anchored in a fixed location while the teeth on the wheel cause the upper strap end to be moved across the lower strap end to merely tension the strap loop. On many of these tools it is possible to adjust the plug too close to the tension position of the wheel with the result that rotation of the wheel without the strap in position between the wheel and plug will cause breakage of the plug or wheel teeth requiring replacement of the parts. It is another object of this in vention to provide an improved constructional relationship -for the positioning of an adjustable plug and the tensioning wheel whereby a satisfactory distance is automatically maintained between the two parts regardless of the position to which the plug is adjusted.

Other objects and advantages of the present invention will be apparent from the following description and claims, and are illustrated in the accompanying drawings which show structure embodying preferred features of the present invention and the principles thereof, and what is now considered to be the best mode in which to apply these principles.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

FIG. 1 is a side elevational view of a strapping tool constructed in accordance with this invention, with its parts shown in positions assumed when the tool grips both the leading .and supply ends of a strap and has tensioned the supply end of the strap;

FIG. 2 is a corresponding side elevational view of the tool with its parts in positions they assume at the beginging of a joint sealing operation (full lines), and with the handle being shown in phantom lines at the position it assumes when a joint is completed;

FIG. 3. is an elevational view of the side of the tool opposite of that of FIGS. 1 and 2 and showing its parts in positions assumed when the tool is ready for the reception of a strap;

FIG. 4 is a sectional view through the various parts of the tool and is taken as indicated on the line 44 of FIG. 2;

FIG. 5 is a fragmentary face view of the seal feeding mechanism and is taken as indicated by the line 55 of FIG. 1;

FIG. 6 is a fragmentary face view of the top of the seal head and is taken on the line -66 of FIG. 1;

FIG. 7 is a section on the line 7--7 of FIG. 1 to illustrate the joint sealing mechanism;

FIG. 8 is a section taken on the line 8-8 of FIG. 1 illustrating the drive for the joint sealing mechanism;

FIG. 9 is a section taken on the line 9--9 of FIG. 2 illustrating the strap aligning lever in operative position;

FIG. 10 is a section taken on the line 10-10 of FIG. 1 and illustrating the strap tensioning mechanism;

FIG. 11 is a lengthwise section taken on the line 11l1 indicated on FIG. 4;

FIG. 12 is a fragmentary section taken as indicated on the line 12-12 of FIG. 11;

FIG. 13 is a transverse section taken on the line 1313 of FIG. 12 to illustrate the drive pawl in its engaged relation to the ratchet and to illustrate the pawl control elements in the positions they assume at this stage.

FIG. 14 is a fragmentary section corresponding gencrs ally to that of FIG. 12 and showing the pawl and pawl control parts in their disengaged position;

FIG. 15 is a transverse section taken as indicated on the line 15-15 of FIG. 14 and illustrating the pawl and pawl control elements in their disengaged positions;

FIG. 16 is an exploded perspective view of the drive pawl, the pawl release pin, and the detent pin better illustr-ating the action and cooperation of these parts; and

FIG. 17 is a fragmentary top plan view of the strap support portion as viewed along 1717 of FIG. 10.

GENERAL DESCRIPTION Referring now to the drawings and particularly to FIGS. 1, 2, 3 and 11 thereof, a preferred embodiment of the strapping tool of this invention is shown therein for the purposes of illustrative disclosure as consisting of a main frame M which is to be engaged against the package being tied, a tensioning mechanism T mounted to swing upon the main frame M about an axis defined by a transverse pin 20, an auxiliary frame F mounted to swing about a transverse pin 21 that is incorporated in the tensioning mechanism T, a seal head assembly H carried on the auxiliary frame F and including seal forming mechanism 22, a seal magazine 23 and seal feeding mechanism 24, and finally, an actuating arm A carried on the seal head H for swinging the seal head H and auxiliary frame F as a unit about the pin 21, with the actuating arm A being rotatable relative to the auxiliary frame F (from full line to phantom line positions shown in FIG. 2) for actuating the

various mechanisms

22, 23, and 24 carried in the seal head H. The tensioning mechanism T includes a gripper wheel unit (see FIGS. 4, 10, and 11) for tensioning the straps S and comprised of mating gripper discs 25 that flank and are locked to a ratchet wheel 26 by lock pins 25F, all to rotate in unison about the pin 21.

The invention contemplates the provision of a strapping tool capable of being handled and operated by one hand and the general arrangement and operation of the device will be apparent to those familiar with combined strap tensioning and sealing tools. The normal position of the tool parts is as illustrated in FIG. 1. The operator may grip the main frame M and actuating arm A in one hand and squeeze to move the parts towards the position illustrated in FIG. 3 to open the device sufficiently to engage upon the overlapping ends of a strap S (FIG. 1) which has been positioned around the package which is to be tied. Relaxation of the grip restores the parts to the position of FIG. 1, but the strap ends are now engaged in retained aligned position within the tool.

The actuating arm A may now be moved counterclockwise as far as the position illustrated in full lines in FIG. 2 and then may be repeatedly cranked towards the position illustrated in FIG. 1 to apply tension to the supply end of the strap while the free end of the strap is held stationary by the tool, thereby tightening the strap about the package to the desired extent. During this strap tensioning action, the actuating arm A and auxiliary frame F move as a unit pivoting about the transverse pin 21. Thereafter, the parts are brought to the position illustrated in full lines in FIG. 2 and the actuating arm A is then pivoted counterclockwise to the phantom line position illustrated in FIG. 2. During this counterclockwise movement of the actuating arm, a previously fed seal is crimped about the overlapping ends of the strap by the seal forming mechanism 22 and the seal feeding mechanism 24 is cocked to supply another seal from the seal magazine 23 for the next strapping operation.

During the strap tensioning cycle, a drive pawl 27 (see FIGS. 4, 11, and 12) carried on the auxiliary frame F, actuates the ratchet wheel 26 while a holding pawl 28 mounted on the pin 20 prevents return of the ratchet wheel, thereby to maintain the set tension on the strap. During the final stages of the operation of the seal forming mechanism 22, the drive pawl 27 is partly rotated counterclockwise as viewed in FIG. 11 to become disengaged from the ratchet wheel as will be described hereinafter. Subsequent clockwise movement of the actuating arm A from the phantom line position of FIG. 2 towards the full line position of FIG. 2 will not further tension the now sealed strap because the drive pawl 27 is disengaged, but such movement enables the seal feeding mechanism 24 to complete the supply of a freshly released seal to the seal actuating mechanism 22 where it is retained until the next package is tied with a strap and the strap tensioned by the tool.

Upon further clockwise movement of the actuating arm A from the full line position of FIG. 2, to and through the position of FIG. 1, the holding pawl 28 is disengaged from the ratchet 26 by the action of a roller 28R journailed on a pin 28F that is carried on auxiliary frame F and thereafter the drive pawl 27 is reset upon engage ment with an abutment cam 29 (see FIGS. 2 and 11) provided on the main frame M to reversely rotate the pawl 27 to a ratchet engaging position. The tool is now ready for the next sealing operation. All of these operations are conveniently performed with a single hand as is made possible by the teachings of the present invention.

SPECIFIC D'ECRIPTION The detailed construction of the parts of the tool may now be described. The main frame M has a generally flat elongated base portion 30 presenting an underface for contact with a package that is to be tied. The base 30 merges with an upstanding wall 31 (FIGS. 3 and 10) medially along one side and merges with a lengthwise handle 32 that extends above the right end of the base as viewed in FIGS. 1 and 2. The region where the handle 32 and the side wall 31 merges is enlarged transversely as indicated at 32T in FIG. 11 and terminates in an overhanging side wall 33 that is spaced from the main side wall 31 (see FIG. 10) to define an open center region for mounting of the tension mechanism T.

The-base 30 is provided at its front end with a strap guide 34 secured by screws 35 (see FIGS. 1 and 9). The strap guide 34 is provided with an overhanging lip 34L to engage the inner edge of the strap ends and maintain the strap against separation prior to application of the seal. The base 30 is also fitted with an insert in the form of a knurled plug 36 (see FIGS. 1 and 2) located beneath the gripper discs 25 to engage and hold stationary the leading strap end which is at the bottom, whereas the gripper discs 25 engage and tension the movable supply end of the strap which is uppermost.

The tensioning mechanism T is mounted in the region between the

side walls

31 and 33 of the main frame M and it includes a cradle 37 that is generally of U-shape to define a pair of depending arms 37A (see FIG. 10). The cradle 37 is journalled on the crosspin 20 that is carried inupper regions of the

side walls

31 and 33 of the main frame M to provide a swingable mounting for the tensioning mechanism T. Adjacent their lower ends, the cradle arms 37A are fitted with ring bearings 38 (see FIG. 4) for rotatably mounting the crosspin 21 on which the gripper discs 25 and ratchet wheel 26 are journalled. The holding pawl 28 for maintaining the gripper discs 25 and ratchet wheel 26 against return movement is journalled centrally on the crosspin 20. The holding pawl 28 is resiliently biased to its illustrated position of FIG. 11 by means of helical springs 40 (see FIGS. 4 and 10). The engagement of the ratchet 26 for the rotation of the gripping discs 25 in a strap tensioning direction is effected through the pulling pawl 27 under the control of a pawl release pin 41 (see FIGS. 4 and 11). These parts are carried in the auxiliary frame F and their function is described hereinafter.

The outboard cradle arm 37A has a downward extension 37F as is apparent in FIGS. 1, 2, and 11 to serve as a foot that rests against the knurled plug 36 when the tool is not in use.

The particular construction shown of the knurled plug 36 offers a special advantage over prior devices. The plug 36 is circular in cross-section and has its sharp upstanding teeth 36A located at a smaller diameter circular portion centrally within the full circular shape.

Surrounding the teeth 36A is a flat annular portion 36B which is at a radial distance in alignment with the path of movement of the downward extension 37F so that this extension 37F rests directly on the annular portion 36B when the cradle 37 is in its biased position as urged by the spring 42, for example, as shown in FIG. 1. One of the shortcomings of prior devices employing adjustable toothed plugs is that they can be elevated too much so that the sharpened teeth of the gripper discs are in contact and interference with the teeth of the plug. Unintentional rotation of the discs when no strap is present between the discs and the plug will then cause breakage of teeth either on the plug or the discs. There is nothing on those devices to limit the adjustment. By the structure shown, any adjustment upward of the plug 36 causes the annular portion 36B to also be elevated because it is an integral part of the plug 36. This, in turn, elevates the contact level of the extension 37F with the plug 36 so that contact between the teeth 25A on the gripper discs 25 and the teeth 36A on the plug 36: is always prevented with the result that accidental breakage of the teeth on the discs 25 or plug 36 is prevented in the situation when no strap is between the discs 25 and the plug 36 and the operator causes the discs to be rotated.

The rear cross wall of the cradle 37 is provided cen trally with a rearward lug 37L to which is anchored one end of an extension type cradle return spring 42 which is nested in a through bore provided in the main frame at the region of the front of the handle 32. The cradle return spring 42 normally urges the cradle 37 and the gripper discs 25 in a counterclockwise direction to load them against the upper strap end. The continuously acting force applied through the cradle 37 and its arms 37A by means of the cradle return spring 42 prevents undesired slippage of the strap. This force is, of course, greatly augmented when the actuating arm A acts to drive the gripper discs 25 through the ratchet system.

Finally, a band guide 37B, as shown in FIGS. and 11, is mounted upon the pin to extend alongside and beyond the outboard cradle arm 37A and terminate in a guide portion 376 that projects into a notch N provided in the base portion 30.

The auxiliary frame F and seal head assembly H are built upon a hollow main body casting 70 having a cylindrically bored generally rectangular upper end 71 and outwardly flaring depending side walls 72, as is best seen in FIG. 7. Fore and aft spaced

cross walls

43 and 44 span the lower portions of the side walls 72, a full height filler plate 73 overlies the front cross wall 43 and the upper end 71 of the main body 70, and finally, a seal housing casting 74 has a lower rear wall 75 overlying the filler-plate 73, with a set of bolts 45 securing the

cross walls

43 and 44, the filler plate 73, and the seal housing 74 in fixed relation upon the side walls 72 of the main body. The rearmost crossplate 44 has a pair of rearwardly projecting side arms 44A pivoted on the crosspin 21 that mounts the ratchet and gripper wheel assembly. The pin 21 is held in place in the side arms 44A of the auxiliary frame F by the bolt 46 and nut 47 and washers 48 all as shown in FIG. 4.

The joint sealing mechanism 22 is mounted within the chamber defined between the

plates

43 and 44 of the auxiliary frame and it may be of any conventional construction known to those skilled in this art. For purposes of disclosure it is shown herein as including a center pair of cooperating sealing jaws 50' which are rotatable about the axes of pivot pins 51. As is conventional, the sealing jaws 50 are flanked by side pairs of sealing jaws 52 which also are rotatable about the axes of the pivot pins 51.

These sealing

jaws

50 and 52 are seen in FIGS. 1, 4 and 11. As is conventional, the center pair of sealing jaws 50 are spaced from each side pair of sealing jaws by a pair of platelike punches 53 which are arranged to engage against the upper face of the seal while it is being deformed by closure of the jaws. These punches 53 together with the sealing jaws are all interenga-ged in side by side stacked relation by a pair of punch return pins 54.

A vertically slidable crosshead 55 operates in the upper end 71 of the main body 70 and (is connected to drive a crosshead pin 56. The crosshead pin 56 is journalled in the upper ends of two links 57 and 58. The link 57 is of a single thickness and is provided with two rollers 59 on a pin 60 at its lower end, the rollers 59 being mounted on opposite sides of the link 57. The link 58 is forked to provide two ears at its upper end with the upper end of the link 57 positioned between the two ears at the upper end of the link 58. The lower end of the link 58 is provided with two rollers 61 (FIG. 7) mounted on a pin 62, these rollers 61 being positioned on opposite sides of this link. (Only one of the rollers 61 is visible in the drawings.)

The four rollers 59 and 61 are used to bear against the upper surfaces 53U of the vertically movable punches 53 to cause their downward movement. The downward movement is caused as the rollers 59 and 61 are moved laterally away from each other and ride up the sloped portions of the upper surfaces 53U of the punches 53.

The movable punches 53 are provided with two closed slotted openings 538 (FIG. 7) which are guided on the pins 51 which confine them laterally during their vertical movement. These pins 51 project in fixed relation into openings in the

crossplates

43 and 44 so they may also serve as pivot pins for the

jaws

50 and 52. These jaws and punches, therefore, are stacked in sandwiched relationship, as is shown in FIG. 11. On each pin 51 is a jaw 52, a punch 53, a jaw 50, a punch 53 and another jaw 52. The three jaws pivoted on each pin 51 are connected together by means of a pin 54 so that all three jaws pivot as a single integral unit on the pin 51. Although there are no further connections on the middle jaws 50, the upper ends 52U of the flanking jaws 52 extend upwardly to where they are pivoted on the pins 60 and 62 which are the same pins that support the four rollers 59 and 61. The pins 54, in addition to connecting the jaws together, cause upward vertical movement of the punches 53 on the return stnoke of the crosshead 55 as the pins 54 react against surfaces 53L.

With this linkage arrangement, when'the crosshead 55 moves downward, this causes, in turn, downward movement of the punches 53 and pivotal movement of the

jaws

50 and 52. As this occurs, the lower central edges of the punches 53 react against the upper surface of the seal 63 (FIG. 7). Also; during this downward movement of the crosshead 55, the

jaws

50 and 52 pivot to move their tips closer together and push the seal legs beneath the two overlapping strap ends which are at this time in alignment through the seal 63. Upon further movement, tne jaw tips react against the bottom portions of the overlapping straps while pressing against the seal legs to serve as the reaction forces opposing the downward force exerted by the lower central edges of the punches 53. This action causes intermediate tab portions of the seal to be severed and bent downwardly to form the conventional interlocking type joint which is Well known in this art. Further details of the jaw action and joint are given in Hall et al. Patent No. 3,032,075 granted May 1, 1962.

During the final formation of the joint, a shear blade 64 (see FIGS. 4 and 11) is driven down by the crosshead pin 56 to score the supply end of the strap as the joint is being held in the joint sealing mechanism 22. Thereafter, when the joint is completed and the tool is removed from the vicinity of the joint, the supply end of the strap is bent and flexed at the score line produced by the shear blade 64 until it breaks at the weakened score line. The shear blade 64 is nested in a central vertical recess provided in the front crossplate 43 and the shear blade has a vertical slot 648 adjacent its upper end to receive the front end of the crosshead pin 56 in .a lost motion relation. The shear blade 64 is retracted when the crosshead 55 elevates the crosshead pin 56 following the joint forming action. The lost motion afforded by the slot 645 enables the

jaws

50 and 52 to be substantially fully operated in their joint forming stroke prior to the operation of the shear blade 64.

The seal housing casting 74 defines a generally rectangular seal storage magazine that is open at the top and bottom and along one side. A pair of shelf brackets 65 are disposed in side by side relation beneath the magazine and have inwardly extending lips 65L defining a band guideway and arranged to receive and temporarily retain each seal as it is discharged from the magazine. Thus, the lowermost seal 63 rests with its legs positioned upon the lips 65L as is best seen in inverted relation at the top of FIG. 5. A follower type plunger 66 is disposed to ride vertically in the magazine and rest upon the uppermost seal of the stack. A helical band spring 67 is coiled about a pin 66 'P within a pocket provided in the follower 66 and the exposed end of the band 67 extends along the open side face of the magazine and anchors within the base 74B of the seal housing casting so that the band spring 67 normally draws the follower downwardly to effect a continuously acting positive seal feed.

Seals may be loaded in stacked relation through the open top of the seal magazine and the stacked seals 63 are apparent in any of FIGS. 1, 2, and 11. In order to I add new seals to the seal housing 74, the follower 66 is removed from the open top end of the magazine by pulling it upward against the force of the band spring 67 which unwinds sufiiciently to permit such travel. After the seals are added, the plunger 66 is replaced in the magazine.

Immediately below the bottom seal of the stack there is provided a seal feed finger 68 (see FIG. 11) that is reciprocable lengthwise in the groove defined by the shelf brackets 65. The free end of this finger 68 is provided with a V-shaped groove for engaging the seal endwise in position for feeding the seal from the stack to the

jaws

50 and 52. The outer captive end of the seal feed finger 68 terminates in a U-shaped portion 68U (see FIG. the arms of which are pivoted on a pin 69 that is carried at the lower end of the bell crank shaped seal feed element 24.

The seal feed element 24 has a front arm 77 and a laterally offset side arm 78. At the region of the juncture of the

arms

77 and 78, the upper end of the front arm 77 is shaped to flank a pair of lugs 74L integrally carried on the seal housing casting 74 and mounting a pivot pin 79 by which the seal feed element 24 is pivoted to the housing 74. A coil Spring 80 encircles the pin 69 and at its ends reacts between the bell crank arm 77 and the seal feed finger 68 to cause the finger to be biased rotationally in a lifting relation against the seal stack. A coil spring 81 encircles the pin 79 and its ends react between the bell crank lever 77 and the seal housing 74 normally to bias the the bell crank rotationally in a counterclockwise sense as viewed in FIGS. 1, 2, and 11. The free end of the side arm 78 of the bell crank is forked and provided with a pivot pin 82 that mounts a cam roller 83 as is best seen in FIGS. 3, 5 and 6.

The actuating arm A is also forked to present laterally spaced mounting ears 84 which are pivotally mounted at opposite sides of the main body casting 70 (see FIG. 8). A one-piece shaft 85 is disposed crosswise within the top of the body casting 70 and has an integral pinion gear 85F formed at its central region and flanked by stub shaft portions 858. Bushings 86 are press fit in opposite sides of the body casting 70 and carry needle bearings 87 to provide an anti-friction mounting for the stub shaft portions 858 which are extended outwardly of the body with the left hand stub portion directly serving as a pivot pin for the left ear of the actuating arm and with the right hand stub portion being knurled or otherwise non-circular at its outer end 85B and engaged in a mating socket provided in an approximately centrally located stub sleeve portion 88S of an outboard cam 88. The stub sleeve 88S presents a circular periphery that serves as a mounting pin for the right hand ear 84 of the actuating arm.

The cam 88 has a mounting arm 88A anchored fast to the actuating arm A by means of a bolt 89 and has a contoured cam sector 88C extending towards the side arm 78 of the bell crank and engageable with its roller 83 to effect pivoting action of the bell crank and withdrawal of the seat teed finger 68 in a predetermined timed relation to the pivoting movement of the actuating arm as it travels from the full line position of FIG. 2, towards the dotted line position of FIG. 2. As stated hereinbefore, it is during this portion of the travel of the actuating arm A that it undergoes relative swinging movement with respect to the main body casting 70. The pinion teeth 85P on the shaft 85 rotate with this movement of the actuating arm to drive the crosshead which is provided with rack teeth 5ST along its upper portion in meshing relation to the pinion teeth P.

It may be noted that the action of the cam 88 in cocking the bell crank occurs concurrently with the action of the pinion 85P in driving the crosshead 55 downwardly for operating the

jaws

50 and 52 and the punches 53 and also for operating the shear blade 64 for scoring the supply end of the strap. At the time that the seal feed finger is cocked sufficiently to engage the lowermost seal of the stack for imparting an end=wise feed motion, a projection 34A on the strap guide 34 serves as an abutment preventing completion of the seal feed cycle until the actuating arm A is reversely swung from the dotted line position of FIG. 2 partway towards the full line position of FIG. 2 to clear the arcuate region of the cam sector 88C sufiiciently to enable the spring 81 of the bell crank to effect return movement of the bell crank and corresponding seal feeding movement of the finger 68.

One-hand operation Mechanism is provided in the rear crossplate 44 to control the timing of the engagement and disengagement of the drive pawl 27 and the rachet 26 in accordance with the particular phase of swinging movement of the actuating arm A. The drive pawl 27 is in the form of a one piece cylindrical pin having arcuate cutouts 27A (FIG. 16) intermediately along it and flanking a set of integral drive teeth 27T that mesh with the ratchet teeth for causing rotation of the ratchet when the auxiliary frame F swings from the full line position of FIGS. 2. and 11 to the full line position of FIG. 1 as it is being repeatedly cranked during the strap tensioning cycle. During this strap tensioning cycle, the rotational position of the drive pawl 27 with respect to crossplate 44 is illustrated in

FIGSv

11 and 13.

The drive pawl 27 has a lengthwise groove 27G along the region that is opposed to the pawl teeth 27T and at one end the pawl has a manual release pin 90 (FIGS. 1 and 2) projecting radially for use in disengaging the pawl where, for one reason or another, tension must be relieved on the strap prior to completing the full strapping cycle. The pawl at its other end has a sector shaped endwise projecting cam 270 which is engageable with the abutment 29 on the side wall 31 of the main frame to reset the pawl from disengaged relation to engaged relation with respect to the ratchet teeth after the sealing cycle has been completed and during the time that the actuating arm is moving towards the full line positions illustrated in FIGS. 1 and 3. The crossplate 44 has a vertical central bore 44V in which a pawl release pin 91 is shiftable. The pawl release pin 91 has a generally cylindrical lower end 91C, a relieved intermediate portion 911 of semi-circular form and provided with an integral lug 92 and a further relieved upper end 91U which underlies an outwardly projecting end 56E on the crosshead pin.

The integral lug 92 of the pawl release pin is engageable in the groove 27G of the driving pawl to effect rotation of the driving pawl 27 in accordance with the vertical position of the pawl release pin 91. When the pawl release pin 91 is elevated (see FIG. 13), it holds the driving pawl 27 engaged with the ratchet 26, and when the pawl release pin 91 is depressed (see FIG. 15), the driving pawl 27 is disengaged from the ratchet 26. The crossplate 44 is provided with a side bore 448 intersecting its vertical bore 44V and accommodating a detent pin 93 and load spring 94 normally to bias the detent pin towards and against the pawl release pin 91. The adjacent side face of the pawl release pin has a conical detent 91D normally receiving the tapered nose of the detent pin 93 so that the detent pin exerts a vertical lifting action holding the pawl release pin 91 elevated and maintaining engagement of the drive pawl 27 with the ratchet 26 (see FIGS. 12 and 13). This relationship obtains during the application of the tool to a band, during the tensioning cycle, and during most of the seal crimping cycle. However, during the final phase of the seal crimping cycle of the jaws and punches, the crosshead pin 56' engages and forcibly depresses the pawl release pin, the detent pin 93 retracting against its load spring 94 to accommodate this, so that the drive pawl 27 is rotated to a position where its teeth 27T are out of engagement with the ratchet teeth (see FIGS. 14 and 15). The detent pin 93 now bears against the side face of the pawl release pin 91 and cannot exert a lifting action and hence cannot re-establish engagement of the drive pawl 27.

The release of the drive pawl 27 at the end of the downward seal crimping stroke of the actuating arm A and crosshead 55 enables return movement of the actuating arm A to the position of FIG. 1 without further tensioning the now-sealed strap. Further return movement of the actuating arm through and past the position of FIG. 1 concurrently releases strap tension and resets the drive pawl 27, and when the position of FIG. 3 is reached, the tool frees the strap and may be removed from the package, it being immediately ready for application to another package to tension and seal a strap about it.

Strap tension on the sealed loop of strap is released by the roller 28R engaging the holding pawl 28 to release the same from the ratchet 26. Reset of the drive pawl 27 is concurrently accomplished by action of the side wall abutment 29 on the cam end 27C causing reverse rotation of the pawl 27 which, in turn, causes elevation of the pawl release pin 91 and enables the detent pin 93 to re-enter the detent 91D and again exert a lifting action that maintains the drive pawl 27 engaged with the ratchet 26.

It will be recalled that the drive pawl 27 normally engages the ratchet 26 during initial application of the tool, during strap tensioning, and during seal crimping until being disengaged as the actuating arm A completes its crosshead lowering stroke. The drive pawl 27 remains disengaged during return of the actuating arm A towards initial position and is reset as the actuating arm completes its return movement. All of the related functions of the tool are also automatically responsive to the actuating arm movement and all in a relationship to require only one hand operation Thus, when the tool is initially cocked to the FIG. 3 position to enable it to engage a strap, one hand is able to grip the handle 32 and actuating arm A simultaneously. Thereupon, the return spring 42 acts to hold the tool engaged upon the strap and one hand is sufiicient to crank the actuating arm through repeated strap tensioning movement. If necessary, such tensioning movement may be interrupted and tension relieving by manually disengaging the drive pawl 27 by means of the conveniently located release pin 90 (FIGS. 1 and 2) followed by swinging the actuating arm A back to the FIG. 1 position.

Once the strap has been adequately tensioned, the actuating arm A is swung to its dotted line position of FIG.

10 2 to effect seal crimping, and thereafter it is swung towards its release position, again only one hand being required. The fact that all operating elements are controlled by the actuating arm including particularly the pawl operation on the ratchet enables this tool to be operated with only one hand.

Thus, while preferred constructional features of the invention are embodied in the structure illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

What is claimed is:

1. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame, tensioning wheel means rotatable about an axis that is swingably carried by said main frame, a sealer head swingable about said axis for movement to and from sealing position, a drive pawl carried with said sealer head having engagement with said tensioning wheel means during swinging movement of said sealer head in a first rotary direction through a first arcuate range of swinging movement, an actuating arm swingable conjointly with said sealer head for driving said wheel means by means of said drive pawl in said first rotary direction, said arm being pivotable relative to said sealer head when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, means responsive to operation of the sealer head for disengaging the drive pawl from the tensioning wheel to avoid further strap tensioning following crimping of the seal, and means responsive toswinging said actuating arm and sealer head through and beyond said first arcuate range of swinging movement for resetting the drive pawl to a position of engagement with said tensioning wheel.

2. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame, tensioning wheel means rotatable about an axis that is swingably carried by said main frame, a sealer head swingable about said axis for movement to and from sealing position, a drive pawl carried with said sealer head having engagement with said tensioning wheel means during swinging movement of said sealer head in a first rotary direction through a first arcuate range of swinging movement, an actuating arm swingable conjointly with said sealer head for driving said wheel means by means of said drive pawl in said first rotary direction, said arm being pivotable relative to said sealer head when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, control means carried with said sealer head and shiftable between first and second stable positions, said control means when in said first stable position acting to hold the drive pawl in engagement with the tensioning wheel means and when in said second stable position allowing the drive pawl to be free of engagement with the tensioning wheel means, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said sealer head to move said control means to said second position during final operation of the seal forming mechanism, and means responsive to movement of said actuating arm and said sealer head in said first rotary direction through and beyond said first arcuate region for releasing strap tension and for resetting said drive pawl to tensioning wheel engagement and returning said control means to said first position.

3. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame, tensioning wheel means rotatable about an axis that is swingably carried by said main frame, an auxiliary frame swingable about said axis, a drive pawl carried by said auxiliary frame and having engagement with said tensioning wheel means during swinging movement of said auxiliary frame in a first rotary direction through a first arcuate range of swinging movement, a sealer head mounted on said auxiliary frame for movement to and from sealing position, an actuating arm swingable conjointly with said auxiliary frame and sealer head for driving said wheel means by means of said drive pawl in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, means responsive to operation of the sealer head for disengaging the drive pawl from said tensioning wheel means to avoid further strap tensioning following crimping of the seal, and means responsive to swinging said actuating arm and sealer head through and beyond said first arcuate range of swinging movement for resetting the drive pawl to a position of engagement with said tensioning wheel means.

4. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame having means providing a fixed pivot axis and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means rotatable about the floating axis, an auxiliary frame swingable about said floating axis, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, a sealer head mounted on said auxiliary frame for movement to and from sealing position, an actuating arm swingable conjointly with said auxiliary frame and sealer head for ratcheting said wheel means by means of said drive pawl in said first rotary direction to cause said wheel means to tension the strap loop, said arm being pivotable relative to said auxiliary frame when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, means responsive to operation of the sealer head for disengaging the drive pawl to avoid further strap tensioning following crimping of the seal, and means responsive to swinging said actuating arm and sealer head through and beyond said first arcuate range of swinging movement for resetting the drive pawl to a position of ratcheting engagement.

5. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame having means providing a fixed pivot axis and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means rotatable about the floating axis, an auxiliary frame swingable about said floating axis, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, a sealer head mounted on said auxiliary frame for movement to and from sealing position, an actuating arm swingable conjointly with said auxiliary frame and sealer head for ratcheting said wheel means in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, control means carried by said auxiliary frame and shiftable between first and second stable positions, said control means when in said first stable position acting to hold the drive pawl in ratcheting engagement with the tensioning wheel means and when in said second stable position allowing the drive pawl to be free of ratcheting engagement with the tensioning wheel means, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said control means to said second position during final operation of the seal forming mechanism, and means responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction through and beyond said first arcuate region for releasing strap tension and for resetting said drive pawl to ratcheting relation and returning said control means to said first position.

6. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame having means providing a fixed pivot axis and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means rotatable about the floating axis, an auxiliary frame swingable about said floating axis, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, a sealer head mounted on said auxiliary frame for movement to and from sealing position, an actuating arm swingable conjointly with said auxiliary frame and sealer head for ratcheting said wheel means in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, a pawl control element shiftably carried in said auxiliary frame to move between a first position wherein the drive pawl is held in ratcheting engagement with the tensioning wheel means and a second position wherein the drive pawl is free of the tensioning wheel means, means resiliently maintaining the pawl control element in said first position, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said pawl control element to said second position during final operation of the seal forming mechanism, and cam means projecting from said drive pawl and responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction and through and beyond said first arcuate region for engaging an abutment on said main frame for reset of said drive pawl and return of said pawl control element to said first position.

7. In a strapping tool for tensioning and sealing the overlapping ends of a strap loop that encircles an object, a main frame having means providing a fixed pivot axis and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means rotatable about the floating axis, an auxiliary frame swingable about said floating axis, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, said drive pawl being rotatably shiftable in said auxiliary frame between a normal position of ratcheting engagement with said tensioning wheel means and a second position free of such engagement, said pawl having an end extension cam and said main frame having a cooperating abutment to engage said cam and offset rotation of said pawl from said second position to said normal position in response to swinging movement of the auxiliary frame in said first rotary direction to move through and beyond said first rotary direction, a sealer head mounted on said auxiliary frame for movement to and from sealing position, an actuating arm swingable conjointly with said auxiliary frame and sealer head for ratcheting said wheel means in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the sealer head is at sealing position to move in an opposite rotary direction for operating said sealer head to crimp a seal about said overlapping ends, a pawl control element slidably carried in said auxiliary frame to m v between first and second stable positions, said pawl control element having interlocking engagement with said drive pawl when acting to hold said drive pawl in normal position and said pawl control element having a sidewise directed detent socket, a detent pin mounted in said auxiliary frame and having a conical point enterable into such socket to hold said control element in its first stable position wherein said control element holds said pawl in normal position, resilient means mounted in said auxiliary frame and yieldably biasing said detent pin against said control element, and means incorporated in said seal forming mechanism and responsive during operation thereof while at the joint forming position for engaging and shifting the pawl control element from said first to said second stable position with said detent pin yieldably retracting from the detent socket to accommodate such movement of the pawl control element.

8. In a binding tool of the type having a main frame that is engageable with an object to be bound and that receives overlapping ends of a loop of strap encircling the object, rotary strap tensioning wheel means swingably mounted about a pivot axis through said main frame and rotatable about a floating wheel axis intermediate of said pivot axis and said main frame, an auxiliary frame carrying seal forming mechanism and swingably mounted about said wheel axis to move to and from joint forming position, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame in a first rotary direction and an actuating arm swingable about said pivot axis conjointly with said auxiliary frame during the first arcuate region of swinging movement for ratcheting said wheel means in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the seal forming mechanism is at joint forming position to move relative thereto in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, the improvement comprising control means carried by said auxiliary frame and shiftable between first and second stable positions, said control means when in said first stable position acting to hold the drive pawl in ratcheting engagement with the tensioning wheel means and when in said second stable position allowing the drive pawl to be free of ratcheting engagement with the tensioning wheel means, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said control means to said second position during final operation of the seal forming mechanism, and means responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction through and beyond said first arcuate region for releasing strap tension and for resetting said drive pawl to ratcheting relation and returning said control means to said first position.

9. In a binding tool of the type having a main frame that is engageable with an object to be bound and that receives overlapping ends of a loop of strap encircling the object, rotary strap tensioning wheel means swingably mounted about a pivot axis through said main frame and rotatable about a floating wheel axis intermediate of said pivot axis and said main frame, an auxiliary frame carrying seal forming mechanism and swingably mounted about said wheel axis to move to and from joint forming position, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame in a first rotary direction and an actuating arm swingable about said pivot axis conjointly with said auxiliary frame during a first arcuate region of swinging movement for ratcheting said wheel means in said first rotary direction, said arm being pivotable on said auxiliary frame when the seal forming mechanism is at joint forming position to move relative thereto in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, the improvement comprising a pawl control element shiftably carried in said auxiliary frame to move between a first position wherein the drive pawl is held in ratcheting engagement with the tensioning wheel means and a second position wherein the drive pawl is free of the tensioning wheel means, means resiliently maintaining the pawl control element in said first position, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said pawl control element to said second position durng final operation of the seal forming mechanism, and means responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction and through and beyond said first arcuate region for releasing tension and for returning the pawl control element to said first position and resetting said drive pawl. I10- In a binding tool of the type having a main frame that is engageable with an object to be bound and that receives overlapping ends of a loop of strap encircling the object, rotary strap tensioning wheel means swingably mounted about a pivot axis through said main frame and rotatable about a floating wheel axis intermediate of said pivot axis and said main frame, an auxiliary frame carrying seal forming mechanism and swingably mounted about said wheel axis to move to and from joint forming position, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame in a first rotary direction and an actuating arm swingable about said pivot axis conjointly with said auxiliary frame during a first arcuate region of swinging movement for ratcheting said Wheel means in said first rotary direction, said arm being pivotable on said auxiliary frame when the seal forming mechanism is at joint forming position to move relative thereto in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, the improvement comprising a pawl control element shiftably carried in said auxiliary frame to move between a first position wherein the drive pawl is held in ratcheting engagement with the tensioning wheel means and a second position wherein the drive pawl is free of the tensioning wheel means, means resiliently maintaining the pawl control element in said first position, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said pawl control element to said second position during final operation of the seal forming mechanism, and cam means projecting from said drive pawl and responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction and through and beyond said first arcuate region for engaging an abutment on said main frame for reset of said drive pawl and of said pawl control element to said first position.

11. In a binding tool of the type having a main frame that is engageable with an object to be bound and that receives overlapping ends of a loop of strap encircling the object, rotary strap tensioning wheel means swingably mounted about a pivot axis through said main frame and rotatable about a floating wheel axis intermediate of said pivot axis and said main frame, an auxiliary frame carrying seal forming mechanism and swingably mounted about said wheel axis to move to and from joint forming position, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame in a first rotary direction and an actuating arm swingable about said pivot axis conjointly with said auxiliary frame during a first arcuate region of swinging movement for ratcheting said wheel means in said first rotary direction, said arm being pivotable relative to said auxiliary frame when the seal forming mechanism is at joint forming position to move relative thereto in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, the improvement wherein said drive pawl is rotatably shiftable in said auxiliary frame between a normal position of ratcheting engagement with said tensioning wheel means and a second position free of such engagement, said pawl having an end extension cam and said main frame having a cooperating abutment to engage said cam and elfect rotation of said pawl from said second position to said normal position in response to swinging movement of the auxiliary frame in said first rotary direction to move through and beyond said first arcuate region, a pawl control element slidably carried in said auxiliary frame to move between first and second stable positions, said pawl control element having interlocking engagement with said drive pawl when acting to hold said drive pawl in normal position and said pawl control element having a sidewise directed detent socket, a detent pin mounted in said auxiliary frame and having a conical point enterable into said socket to hold said control element in its first stable position wherein said control element holds said pawl in normal position, resilient means mounted in said auxiliary frame and yieldably biasing said detent pin against said control element, and means incorporated in said seal forming mechanism and responsive during operation thereof while at the joint forming position for engaging and shifting the pawl control element from said first to said second stable position with said detent pin yieldably retracting from the detent socket to accommodate such movement of the pawl control element.

12. The combination in a hand held portable strapping tool comprising a main frame having a handle arched above a base that is adapted to engage against an object to be tied by a strap loop having overlapping lead and supply ends, said handle terminating in laterally flaring wall structure that merges at one extremity with upstanding side wall structure of said base and cooperatively therewith provides opposed regions that flank and define a central pocket, said main frame having means providing a fixed pivot axis extending between said opposed regions and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means mounted to rotate about the floating axis, an auxiliary frame swingable about the floating axis, said auxiliary frame carrying a seal head assembly that includes casing structure rigid with the auxiliary frame and housing seal forming mechanism, seal storage mechanism and seal feeding mechanism, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, spring means reacting between the main frame and the tensioning wheel means normally to maintain the floating axis at a location that is maintained during the said first arcuate range of swinging movement, an actuating arm pivotable about an axis through said casing structure but movable conjointly with the auxiliary frame for ratcheting said wheel means in said first rotary direction, said arm being pivotable about said casing axis when the seal forming mechanism is at sealing position to move in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, means responsive to operation of the sealer head'for disengaging the drive pawl to avoid further strap tensioning following crimping of the seal, and means responsive upon swinging said actuating arm and auxiliary frame through and beyond said first arcuate range of movement for elevating the wheel means against the action of said spring means for setting the drive pawl to a position of ratcheting engagement.

13. The combination in a hand held portable strapping tool comprising a main frame having a handle arched above a base that is adapted to engage against an object to be tied by a strap loop having overlapping lead and supply ends, said handle terminating in laterally flaring wall structure that merges at one extremity with upstanding side wall structure of said base and cooperatively therewith provides opposed regions that flank and define a central pocket, said main frame having means providing a fixed pivot axis extending between said opposed regions and means mounting a floating axis parallel to and swingable about the pivot axis, tensioning wheel means mounted to rotate about the floating axis, an

Cit

auxiliary frame swingable about the floating axis, said auxiliary frame carrying a seal head assembly that includes casing structure rigid with the auxiliary frame and housing seal forming mechanism, seal storage mechanism and seal feeding mechanism, a drive pawl carried by said auxiliary frame and having ratcheting engagement with said tensioning wheel means during swinging movement of said auxiliary frame about the floating axis in a first rotary direction through a first arcuate range of swinging movement, spring means reacting between the main frame and the tensioning wheel means normally to maintain the floating axis at a location that is maintained during the said first arcuate range of swinging movement, an actuating arm pivotable about an axis through said casing structure but movable conjointly with the auxiliary frame for ratcheting said wheel means in said first rotary direction, said arm being pivotable about said casing axis when the seal forming mechanism is at sealing position to move in an opposite rotary direction for operating said seal forming mechanism to crimp a seal about said overlapping ends, a pawl control element shiftably carried in said auxiliary frame to move between a first position wherein the drive pawl is held in ratcheting engagement with the tensioning wheel means and a second position wherein the drive pawl is free of the tensioning wheel means, means resiliently maintaining the pawl control element in said first position, means responsive to pivoting movement of said arm in said opposite rotary direction relative to said auxiliary frame to move said pawl control element to said second position during final operation of the seal forming mechanism, and means responsive to movement of said actuating arm and said auxiliary frame in said first rotary direction and through and beyond said first arcuate region for releasing tension and for returning said pawl control element to said first position and resetting said drive pawl.

14. An arrangement in accordance with claim 13 and wherein a holding pawl is rotatable upon the pivot axis for the tensioning wheel means and is resiliently biased to holding engagement therewith and a release element is carried on the auxiliary frame to engage the holding pawl when the actuating arm is swung to adjacent the handle and lifts the tensioning wheel means against the action of said spring means.

15. In a strapping tool for tensioning the overlapping ends of a strap loop encircling an object comprising a frame, a tensioning wheel mounted on the frame for movement toward and away from a strap gripping station on the frame, said strap gripping station being provided with a strap gripper which is adjustably mounted for positioning the strap gripper at different strap gripping levels at said strap gripping station, a spacer member movable conjointly with said tensioning wheel and projecting in a radial direction beyond the wheel and in the path of the strap gripper at any position to which it can be adjusted, whereby movement of-the tensioning wheel to the strap gripping station allows contact of the projecting part of said spacer member with the strap gripper to thereby maintain a minimum spacing between the tensioning wheel and the strap gripper corresponding to the amount the spacer member projects beyond the wheel.

16. In a strapping tool for tensioning the overlapping strap ends of a strap loop encircled about an object comprising a frame, a strap gripping station on the frame over which the strap ends are extended when tensioning, a strap gripper mounted in the frame at said station and adjustable to different levels, a tensioning wheel mounted on the frame for movement toward and away from said station and provided with a spacer member movable conjointly with the tensioning wheel, said spacer member projecting radially beyond the tensioning wheel and in the path of the strap gripper at any position to which it is adjusted, whereby the spacer member contacts said strap gripper when the tensioning wheel is moved to said station, the amount the spacer member projects beyond 17 the tensioning wheel determining the spacing between the tensionin wheel and the spacer member.

17. In a strapping tool as defined by claim 16 comprising said strap gripper being circular in cross-section and provided with an annular surface which provides said contact with said spacer member through a full 360 positioning of said strap gripper.

18. In a strapping tool as defined by claim 16 comprising said strap gripper being threadably secured to said frame to provide its adjustment to said different levels by rotating it, an annular surface being provided on the strap gripper in alignment with the spacer member to provide a full 360 region of contact between the strap gripper and the spacer member.

References Cited UNITED STATES PATENTS 1/ 1937 Waldorf 140-93.4 12/ 1937 Spencer 14093.4 12/ 1943 Leslie 14093.4

2/1950 Leslie 14093.4 12/1953 Crosby et a1. l40--93.4

5/1962 Hall et a1 14093.4

10 CHARLES w. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner.