US2229786A - Strip tensioning apparatus - Google Patents

Description

Jan. 2s, 1941. G. J. ABBOTT 2,229,786

STRIP TENSIONING APPARATUS Filed April '7, 1939 3 Sheets-Sheei'l 1 Jan. 28, 1941. Q 1 ABBOTT 2,229,786

STRIP TENS IONING APPARATUS Filed April 7, 1939 3 Sheets-Sheet 2 Jan. 28, 1941. G. J. ABBQT 2,229,786

STRIP TENSIONING APPARATUS Filed April 7, 1959 s Sheets-sheet 5 Patented Jan. 28, 1941 PATENT OFFICE STRIP TENSIONING APPARATUS Georey Joseph Abbott,

Carshalton, England, as-

signor to Packers Supply Company I limited, Surrey, England, a company of Great Britain Application April 7, 1939, Serial No. 266,667 In Great Britain April 13, 1938 11 Claims.

This invention relates to apparatus for tensioning strip material such as binding strapping, round or elliptical cross section wire or the like, and is particularly applicable to apparatus for tensioning metal strapping such as is employed for binding barrels, boxes, bales, crates and like bodies.

The improved apparatus is of the kind in which the tensioning operation is effected by the movement of members which grip the strip material between them and in accordance with the invention the tensioning members are larranged to move apart after making a movement of given extent in the direction in which they are moved for tensioning the strip.

Thus during the tensioning operation the material being tensioned cannot be bent through an excessive angle and is therefore not subjected to such stresses as would give it a permanent set or kink it, and it remains therefore in condition for use in a subsequent strapping operation. The parts of the tensioning means may be so arranged that when freed, they move by gravity into the position corresponding to the maximum movement of which they are capable in the direction in which they are moved to tension a strip. Thus, when at rest, the tensioning members always remain apart and the strip material can be inserted therebetween with ease.

In the preferred arrangement the surface of one oi the pivoted gripping members engaging the strip material conforms to a smooth curve of large radius to which the part of the strip to be moved lies approximately tangential, and this again serves to avoid excessive bending of the strip material.

The tensioning members are moved by rocking a pivoted lever and the arrangement is such that by imparting longitudinal thrusts to this operating lever, the tensioning members can be brought rapidly into gripping engagement with the strip or can be forced from gripping engagement with the strip against the tendency which the gripping members may have to bind on the strip due to the bite of the usually serrated surface of at least one of the gripping members. The release of the strip from the grip of the tensioning members takes place without imposing any stresses upon the strap such as would be liable to bend or buckle it.

The improved tensioning means may be conveniently combined with means for joining the overlapping ends of the strip material, to form a single tool, and a further feature of the present invention resides in disposition of the parts ci the tool relatively to one another in such a manner that a combined tool of minimum overall length is achieved. 'I'hus a tool is provided which can be used for binding smaller packages than hitherto and furthermore the extent to which the tensioned and jointed strapping is slackened when the base of the tool is removed from between the package and the strapping is reduced.

The invention is illustrated by way of example in the accompanying drawings as applied to a combined tensioner and jointing tool for 'use with iiat metal strapping.

In the drawings:

Fig. 1 is a front elevation of a complete machine,

Fig. 2 is a plan view of Fig. 1,

Fig. 3 is a rear elevation, and Fig. 4 an end elevation looking from the left hand end of Fig. 1,

Fig. 5 isa view of parts in perspective to illustrate the manner in which strapping is inserted in the tool and tensioned,

Figs. 6 and 7 are views in perspective showing the tensioning members and Figs. 8, 9, 10' and 11 are detail views in side elevation and partly in section showing the tensioning means in various positions, l

Fig. 12 is a plan viewof the machine with the top cover plate removed,

Fig. 13 is a `sectional elevation on the lines ls-ls of Fig. 12, A

Fig. 14 is a sectional end elevation on the line lll- I4 of Fig. 13,

Fig. 15 shows the two ends of a length of strapping jointed together by the improved tool, and

Fig. 16 is a view in section on the line I6--I6 on Fig. 15. l

Referring to the drawings, the body of the tool which may be a steel casting, comprises a base plate I and a box-like structure 2 above said base plate forming a housing for the moving parts of the joint-forming mechanism. The base plate is provided with a longitudinal recess 3 within which is mounted the xed lower die A of the jointing means, and the lower front portion of the box-like structure 2 extends overbut is spaced from the surface of the base plate to permit the metal strapping to be placed in position between the die 4 and the box-like structure 2 (see Fig. 4).

On the ends of the base plate l are formed upstanding lugs 5 and 6 through which extend spindles l and 8. On the ends of the spindles at the frontof the tool are xedly mounted pawls 9 and I0 respectively and on the rear ends are xedly mounted hand levers Il and I2 whereby the spindles 1 and 8 can be rocked in the bearing lugs 5 and 6.

The pawls 9 and I8 are shaped so that a part of the periphery is eccentric with regard to spindles 1 and 8 and can be brought into contact with the bottom of the recess 3 in base plate I by rocking the hand levers II and I2. Springs I3 and I4 are provided between pins on the handles and anchorages on the tool body which when the hand levers II and I2 are rocked move to one side or the other of the axis of the respective spindle 9 or I8 and serve to hold the pawls either in engagement with the bottom of the recess in the base plate I or with metal strapping therein as shown in Fig. 5 or out of engagement from the bottom of said recess as shown in Fig. 1. The extent to which the pawls 9 and IIJ 'can move away from the base plate is limited by the engagement of stops I5 on the hand levers Il and I2 with the base of the tool (see Fig. 3), but in the disengaged'position the pawls are so spaced above the base plate as to permit easy insertion of strapping beneath the pawls.

The pawls 9 and II) are provided with radially projecting lips I6 which engage in extensions I1 of the depression 3 in the base plate I when the pawls are in the position shown in Fig. 5.

In use the tool is placed upon the box, bale, case or the like to be bound and hand levers II and I2 operated to bring the pawls 9 and IIJ into the open position shown in Fig. 1.

Thereupon the free end I8 of the metal strapping is inserted between pawls 9 and I0 and the base plate I, Fig. 5, and arranged over the lower die 4. Hand lever II is now rocked to cause the pawl 9 to move into the position to grip the inserted end of the strapping as shown in Fig. 5, and the strapping is thereafter passed round the box, bale, case or the like and inserted between pawl I and the base plate I, over the previously inserted free end of the strapping as shown at I9 in Fig. 5 and through the tensioning means generally indicated at 28 in that figure, and the hand lever I2 is then rocked to bring the pawl down on to the strapping also as shown in Fig. 5. 'Ihe lips I6 on the pawls serve to retain the inserted strapping in position beneath the pawls until the latter are moved into their gripping positions.

Thereafter the strapping is tensioned about the box, bale, case or the like by pulling upon the end 2| of the strapping and it will readily be seen that the pawl 9 will effectively resist any tendency on the part of the end I8 of the strapping to move in the direction to the left in Fig. as a result of the pull on end 2I. Similarly pawl I0 makes a one-way grip upon the strapping such that while a pull on end 2| draws the strapping lbetween said pawl I0 and the base plate to the left in Fig. 5, movement of the strapping in the reverse direction beneath the pawl I0 is prevented by the grip of the pawl.

The means for pulling upon the end 2I of the strapping to tension the strapping about the box, bale or case is as follows:

On the end of the box-like structure 2 at one end of the tool, is provided a pair of lugs 22 extending longitudinally of the tool and in the direction beyond one-way grip pawl 9v from the die 4.

' These lugs 22 form a bearing for a spindle 23 lying transversely of the tool and on this spindle is mounted a. body shaped as shown in Fig. 7. This body comprises a yoke 24 apertured as shown at 25 for mounting the body on spindle 23. One

arm of the yoke is provided with a downward extension or arm 26 in a plane at right angles to the axis of rotation of the body on spindle 23 and this arm 26 is provided with a lateral projection 21 at its lower end which when the body is mounted on spindle 23 in lugs 22 lies transversely of the tool and in the vertical plane containing pawls 9 and I8.

The surface 28 of the projection 21 is slightly curved and serrated and the front edge 29 is bevelled, the bevel leading inwards towards surface 28.

The ends of the yoke 24 are apertured at 30 to receive a pivot pin 3I for an operating lever 32. The operative end 33 of this lever 32 is shown in Fig. 6 and is of curved formation making approximately a right angle with the main part of lever 32. An aperture 34 is provided in the angle of lever 32 to receive the pivot spindle 3l carried in the aperture 30 of body 21.

The lower surface of part 33 is curved smoothly and when the lever 32 is mounted on pin 3l, lies between the pivot spindle 23 and the surface 28 of projection 21.

The length of the part 33 is substantially greater than the width of the surface 28 of projection 21 and at least the major portion of the lower curved surface of part 33 when mounted conforms approximately to an arc of a circle to which the line of a length of strapping extending through the tool lies at a tangent, as clearly shown in Fig. 5.

The arrangement is such that lever 32 is movable to a limite-d extent about pivot 3l relatively to body 24, 26, 21, this movement being limited on the one hand by contact of the lower curved surface of part 33 with the surface 28 of proj'ection 21 and on the other hand by contact of the upper surface of part 33 with for example the underside of part 24 of the shaped body.

The distance between the aids of spindle 23 and the surface 28 of projection 21 is kept short relatively to the radius of curvature of the lower surface of part 33 of lever 32.

The lower surface of part 33 of lever 32 is preferably smooth or without serrations and the forward or front edge thereof is provided with a downwardly extending lip 35 preferably bevelled at the rear, this lip 35 being capable of overlapping the edge of surface 28 of body 21 and being adapted to assist in retaining strapping inserted between the part 33 and surface 28, see Fig. 5.

'Ihe main portion of tensioning lever 32 is cranked as shown at 36 so that the free end lies over the top of the box-like structure and rests inter-mediate its length on a fulcrum 31 at the end of the structure 2 nearest the operative end 33 of the lever. The arrangement is such that in the rest position the lever 32 tilts clockwise in Fig. 1, by gravity about the fulcrum 31 and moves the shaped body 24, 26, 21 about its pivot spindle 23 into the position shown in Figs. 1 and 11 where the underside of part 33 of lever 32 is spaced from the surface 29 of the shaped body. Thus with the lever 32 in this rest position the end I9-2I of the strapping (Fig. 5) can readily be inserted between the parts 33 and 21 of the tensioning means.

The length of strapping having been placed in position as previously described, and the end 2|' inserted between the parts 33 and 21 of the tensioning means, tensioning of the strapping about the box, case, bale or the like is effected by rocking the lever 32. The lever 32 is first moved counter-clockwise from the position of Figs. 1 and' 11 to that shown in Fig. 8, taking with it the shaped body including part 21 by virtue of the engagement of part 33 of lever 32 with the underside of part 24 of the shaped body. The parts 33 and 21 during this movement move freely along the strapping until movement of part 21 is arrested by contact with a fixed part of the tool such as lug 5. Thereupon lever 32 is rocked in the reverse or clockwise direction and part 33 of the lever iirst moves about spindle 3l towards surface 28 of part 21 so that the strapping is gripped (see Fig. 9). Continued movement of lever 32 in the same direction causes movement in unison of part 33 of said lever and part 21 of the shaped body about spindle 23, together with the strapping gripped between them so that the part ISI-2| of the strapping is drawn to the left in Figure 5 and beneath pawl I I).

The lever 32 having been moved in this direction to a given extent, its movement is reversed. Thereupon part 33 is rocked about spindle 3| so that the grip of parts 33 and 21 on the strapping is released and part 21 is moved by the engagement of part 33 of lever 32 with the undermde of part 24, back to a position in the region of that shown in Fig. 8 in preparation for taking a fresh grip upon the strapping when the lever 32 is again moved clockwise.

Return movement of the tensioned strapping when released from the grip of parts 33 and 21 is prevented by one-way gripping pawl I0 in the Ymanner previously described.

A succession of these to and fro movements of lever 32 may be required to tension the strapping to the required extent.

It will be observed that the amplitude of the rocking tensioning movement is positively limited since engagement of lever 32 with fulcrum 31 has the effect of moving part 33 away from surface 28 so that pull on the -strapping ceases. 'I'his in conjunction with the large radius of curvature of part 33 ensures that the strapping passed through the tensioner is bent only to a very small extent through a flat smooth curve so that it is not kinked or given a permanent set and remains in condition for use in a subsequent strapping operation. Furthermore the lower surface of part 33 being smooth the outer or finally exposed surface of the strapping is not scratched or otherwise marred.

Should the part 33 and surface 28 tend to bind upon the strapping between them, a longitudinal pull upon lever 32 will rock the shaped-body about spindle 23 to effect a positive disengagement. Similarly a longitudinal thrust may be imparted to lever 32 to rock the shaped body relatively to part 33 to bring about a rapid and eiiective grip on the strapping.

The strapping having been tensioned to the desired extent about the box, case, bale or the like, the end of the strapping adjacent the tensioner is severed and the overlapping ends (I8 and I9 in Fig. 5) joined together.

In the case illustrated a joint is formed as shown in Figs. 15 and 16, the overlapping ends of the strapping I8 and I9 being shaped between dies to form a longitudinal ridge 38 with sloped ends 39, 4U and a staggered series of tongues 4I being punched down from the upper overlapping end at each side of the ridge and passing through corresponding apertures or slots 42 in the lower overlapping end. The tongues 4I are turned under and are housed in the space beneath the ridge. Y

The means for severing the strapping and joining the ends is as follows: 1

The lower fixed die 4 referred t0 above as being located in the recess 3 in base plate I, is shaped in cross section as shown in Fig. 14 to provide the ridge 43.

Within the box structure 2 is mounted an upper die member 44, this member being in the form of a metal block arranged for vertical sliding movements, above fixed die 4, in guides 45 fixed to the inside of the end Walls of the box structure 2. The metalblock 44 at'its lower end is slottedin its median plane as shown at 46Fig. 14 and the parts on each side of the slot are divided in such a manner as to form two series of uniformly spaced fingers 41 the lingers in one part being opposite the spaces between fingers in the other part.

The extremities of the lingers 41 are oppositely bevelled as shown at 48 so that the ends are parallel to the sides of the ridged ixed die 4.

The outer ends 49 of the lower portion of the metal block are shaped to co-operate with the ends of the lower die 4 to form the sloped ends 39 and 40 of the joint shown in Fig. 15.

.At the lower left-hand corner of block 44 in Fig. 13 there is formed a shearing or cutting edge 5I] for cooperation with a fixed shear 5I to sever the part 2| of the strapping extending over said shear 5I, from part I9 (Fig. 5) as the metal block 44 is moved downwards.

The upper end of block 44 is provided with a recess 52 in which is located a cam 53 on a shaft 54 mounted eccentrically in bearings in the front and -rear walls of box-like structure 2, this cam making engagement with the bottom of recess 52.

Shaft 54 may be rocked by a handle 55 fast on the end thereof and the cam 53 is shaped so that the block 44 is fully depressed after the shaft has rocked counter-clockwise in Fig, 13 through approximately and thereafter the cam surface is concentric with the axis of rotation so that it serves to maintain the block 44 in its lowered position during further movement of the shaft in the same direction.

This downward movement of block 44 severs the strapping between the shears 50 and 5I and presses the overlapping ends of the strapping down on to the die 4 and forms the ridge 38 (Fig. l5).

A leaf spring 56 spans the recess in, and is fixed to, block 44, and is engaged by cam 53 to lift block 44 upon a return movement of shaft 54 and lever 55.

Also mounted in the box-like structure 2 are two metal frames 51 arranged for up and down movements in obliquely arranged downwardly converging slots 58 in the guides 45 within the box 2.

These metal frames at their lower ends are each provided with a series of fingers 59 which project into the spaces between the fingers 41 of the moving die 44 and the fingers 59 are recessed for the reception of hardened steel punches 60.

The frames 51 are movable up and down in their oblique guide slots 58 by the rocking of the eccentric shaft 54 and through the medium of transmission blocks 6I, Fig. 14, fitted at an inclination on shaft 54 and mounted in the metal frames 51.

with `upper and lower parts of the metal frames 51 so that they' may slide laterally in the frames as the blocks are moved by the eccentric shaft 54 to thrust the frames up or down.

As the shaft 54 is rocked by means of lever 55 as previously described, the frames 51 ai'e moved downwards and the punches, moving between the fingers 41 of movable die 44, approach fixed die 4.

As previously stated the movement of die 44 ceases after lever 55 has been'rocked through approximately 90. The movement of the frames 51 however is progressive throughout the movement of lever 55 and shaft 54 through approximately 180 and the punches 60 are thrust down between the stationary lingers 41 of the upper die and through the overlapped ends of the strapping to form the tongues 4| and apertures 42.

The fixed die is provided with a number of apertures 63 permitting passage of the ends of the punches 6D.

The joint having been made, the lever 55 is rocked in the reverse direction and the frames 51 are lifted positively by shaft 54 and blocks 6I to disengage the punches from the strapping and only after such disengagement, is the movab-le die 44 lifted by the engagement of cam 53 with leaf spring 56 to release the jointed ends of the strapping from between the dies.

The ends of the base plate I being above the level of the bottom of fixed die 4 in recess 3, the tension of the joined strapping will lift the jointed ends free of the die 4 as soon as the upward movement of movable die 44 commences.

The punches 60 are preferably of increasing length from one end of the tool towards the other as shown in the drawings so that the tongues 4l and slots 42 are formed in succession along the joint from one end to the other so that the considerable effort which might be necessary in effecting all the piercing simultaneously is avoided.

An important feature of the improved tool is that the tensioning means 33, 21 is disposed at one end of the tool at the side of pawl 9 away from the dies and above it.

Both the pawls 9 and I0 may therefore be arranged close to the ends of the fixed die 4 so that a tool is achieved of which the part which lies beneath the strapping to be tensioned is of a minimum length, so that the tool is capable of being employed in strapping packages of smaller size than with hitherto known strapping tools and the degree to which the strapping is slackened when the tool is removed from beneath it is lessened.

I claim:

1. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a second member pivoted on the first member for movement about an axis spaced from the pivotal axis of the rst member on the support and adapted to co-operate with said first pivoted member to grip and move the strip, a lever for moving said second pivoted member into the position of cooperation with the first pivoted member to grip a strip between them and thereafter to move the two pivoted members and the strip together to tension the strip, and means so positioned so as to rock said lever, as the end of its movement in the direction for tensioning the material is approached, about a point intermediate the length thereof to move the pivoted members apart.

2. Means for tensioning a stri-p of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member pivoted on saidgiirst pivoted member for movement about an axis spaced from the pivotal axis of the rst member on the support, said second .pivoted member having a smooth flat curved surface adapted to co-operate with the surface on the projection on the first pivoted member to grip and move the strip, and gravity controlled means adapted to move the smooth flat curved surface of one pivoted member and the surface of the projection on the other pivoted member away from one another as said pivoted members approach the limit of their movement in the direction for tensioning a strip.

3. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member pivoted on said first pivoted member for movement about an axis spaced from the pivotal axis of the first member on the support, said second pivoted member having on the side towards the projection on the first pivoted member a long curved surface of large radius relatively to the radial distance of the pivotal axis of the first mentioned pivoted member from the surface of the projection thereon, and reciprocable means adapted when moved in one direction to first move the second pivoted member towards the projection on the first pivoted member and to thereafter move the rst pivoted member by and with the second pivoted member.

4. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member pivoted on the rst member for movement about an axis spaced from the pivotal axis of the first member on the support and adapted to co-operate with the projection on the first pivoted member to grip and move the strip, a reciprocable lever connected with the second pivoted member, means for limiting the movements of said lever in both directions and means so positioned that the two pivoted members are moved apart as the lever is moved into either of its extreme positions of said lever.

5. Means for tensioning a strip of material about a body comprising a support, a member pivoted on said support, a projection on said pivoted member located below the pivot thereof, a second member pivoted on the first pivoted member for movement about an axis spaced from the pivotal axis of the first member on the support, said second member including an arcuate portion extending between the pivot of the first mentioned pivoted member and the projection thereon and adapted to `co-operate with said projection to grip and move the strip.

6. Means for tensioning a strip of material about a body comprising a support, a member pivoted on said support, a projection on said pivoted member located below the pivot thereof, a second member pivoted on the rst pivoted member for movement about an axis spaced from the pivotal axis of the first pivoted member on the support, said second member including an arcuate portion extending between the pivot of the first mentioned pivoted member and the projection thereon and the operative surface of said arcuate portion conforming to part of a circle to which a strip of material extending across the support lies at a tangent and being adapted to co-operate with the projection of the first mentioned pivotedmember to grip and move the strip.

'7. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member pivoted on the first member for movement about an axis spaced from the pivotal axis of the first member on the support, reciprocable means adapted, when moved in one direction, iirst to move the second pivoted member about its axis towards the projection on the first pivoted member to grip a strip between said second member and the projection, and thereafter to move the first and second pivoted members and the strip gripped between them bodily about the axis of the first pivoted member, and means so positioned as to move the strip gripping members apart during an extended movement of the reciprocating means in the same direction.

8. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a second member pivoted on the first member, reciprocable means adapted to move the second pivoted member into co-operating relationship with the rst pivoted member to grip the strip between them and thereafter to move the first and second pivoted members and the gripped strip bodily to tension it, and means so positioned as to impose a secondary rocking movement on the second pivoted member during an extended movement of the reciprocable means in the direction for tensioning the strip to move the pivoted members relatively to one another to release their grip on the Strip.

9. Means for tensioning a strip of material about a body, comprising a support, a gripping member pivoted on said support, a second gripping member adapted to make movements of limited extent relatively to the rst pivoted member and to (io-operate therewith to grip and move the strip, a reciprocable lever adapted for moving said second gripping member into the position of -co-operation with the rst pivoted member and gripping the strip between them and thereafter moving both said gripping members and the gripped strip bodily to tension the strip, and means forming a ulcrum for engagement by an intermediate part of the lever, said fulcrum being so positioned that the lever when free makes an extended movement by gravity in the direction in which it moves to tension the strip and during such movement moves the pivoted members apart to release the strip.

10. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member mounted for movement eccentrically with regard to the rst mentioned pivoted member, a lever for moving the eccentrically mounted member into co-operative relationship with the projection on the rst pivoted member to grip the strip between them and to thereafter move the first pivoted member and the gripped strip by and with the second pivoted member, and means so positioned that the lever is rocked about a point intermediate its length and the second pivoted member and the projection move apart to release the strip when the lever makes an extended movement in the direction for tensioning the strip.

11. Means for tensioning a strip of material about a body, comprising a support, a member pivoted on said support, a projection on said pivoted member, a second member pivoted on the rst member for movement about an axis spaced from the pivotal axis of the first member on the support, a lever rigid with the second pivoted member and adapted to move the second pivoted member into and out of contact with the projection on the first pivoted member on the one hand by movement of said lever together with the second pivoted member about the pivotal axis of the second pivoted member on rthe rst pivoted member, and on the other hand by movements of the lever longitudinally of itself which move the rst pivoted member about its pivot on the support.

GEOFFREY JOSEPH ABBO'I'I.

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