FIELD OF THE INVENTION

This invention relates to the automatic appli¬ cation of ties. BACKGROUND TO THE INVENTION It is often necessary to tie bundles of elongate objects together, for example bundles of cables or wires which if left unbound might present a hazard as well as being unsightly. One way in which cables are often bound together is by flexible plastic ties which have an integral fastener, or buckle, at one end through which the tail end of the tie is threaded once it has been passed around the bundle of cables. Manual application of the ties is slow and laborious, and it is therefore desirable to have a tool which automatically performs "the binding operation. PRIOR ART

A gun for automatically applying ties has been designed in which a pair of jaws can be closed around a bundle of cables, and a flexible tie pushed forwards by a plunger so that the tail is pushed around the loop defined by the jaws and through an apertured buckle at the other end of the tie. The tail is then pulled tight, twisted by 90 with respecf to the buckle to lock it in place, and the excess length cut off. Ties are supplied singly to this gun from a pre-loaded magazine

which is mounted on the exterior of the gun. Some of the disadvantages of such a gun stem from the type of tie which is used; the "twist and lock" type of tie has to be overtensioned then relaxed back before it locks, which does not always provide satisfactory tensioning, also the fastened tie has a knobby finish at the buckle, which is apertured so that the tail of the tie is threaded at approximately right angles to the longitudinal direction of the tie adjacent the fastener. Furthermore the gun is made in a sealed unit which is heavy, bulky and cannot be readily serviced.

Another gunhas beenproposed in which ties are conveyed one at a time from a magazine mount.ed remote from the gun, but is otherwise similar to that previously described. A third machine uses separate buckles and a continuous spool of tape ^" . Neither of these machines has proved consistently reliable in use. OBJECT OF THE INVENTION

The present invention is directed towards a tie gun which may provide a reliable tie feed mechanism, which may be readily serviced, and which may incorporate standard replaceable components. SUMMARY OF THE INVENTION

Tie applying tools or guns provided in accordance with this invention, and to be described herein, utilise- a belt or bandolier of ties connected in parallel arrangement by integral bridging pieces, and preferably fed into the gun from a replaceable magazine in which the bandolier is coiled. The buckle or head, of the tie is formed with an aperture which extends through the

" buckle transverse to the plane of the tie ^" ^ In the gun, o the buckle portion of the tie is orientated at 90

"(relative to the remainder of the tie) prior to the tie being pushed tail-first from the gun around the bundle or roll to be tied, said head orientation being such as to

ensure that the tail will be directed through the buckle aperture after said tail has been guided around the bundle and back towards the gun.. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:

Figure 1A shows a small part of the length of a bandolier according to a preferred embodiment and Figure IB is a sectional view thereof;

Figures 2A to 2D show details of the tie in the preferred embodiment of Figure 1;

Figure 3 shows the interior of an opened magazine for the bandolier of Figure 1; Figure 4 shows the closed magazine;

Figures 5A and 5B are sectional views on the lines A-A and B-B of Figure 4

Figure 6 is a plan view of a preferred embodiment of tie gun, for use with the bandolier and magazine of Figures i to 5;

Figure 7 is an eievational view inside a side wall of the gun of Figure 6;

Figures 8 and 8A show to an enlarged scale details at the front end of the gun of Figure 6, including a nose loop assembly;

Figure 9 shows the construction of a pusher rod in the gun of Figure 6;

Figure 10 shows detail of a changeover valve assembly in the gun of Figure 6; Figure 11 and 11A show details of an entrance region of the gun of Figure 6, at which entrance ties are fed in from a magazine, and also showing a tie-indexing assembly; and

Figures 12, 12A and 12B show details associated with a tie-cutting assembly of the gun of Figure 6.

DETAILED DESCRIPTION

Figure 1A shows part of a bandolier 8θ of ties 100, each tie having a head with a tail trailing therefrom, the head being apertured in a direction transverse to the plane of the tail to receive the free end of the tail when the tie is being tied. The bandolier comprises say 500 ties in parallel side-by-side arrangement, with each pair of adjacent ties being interconnected by -two integral bridging pieces 90. The bridging pieces 90 connect to the tails 102 of the ties through grooves _*

defining lines of weakness or breakage 94 just inside the projected lines of the longitudinal edges 96 of the tails 102.

In use, the knife means in the gun acts to apply a break-off pressure to the bridging pieces substantially in line with the longitudinal edge 96 of the tail 14, and causes the bridging pieces 52 to break off substantially along the lines 9 . _% Th s, any defects or roughnesses along the breakage lines will not project laterally beyond the full width of the tail between its longitudinal edges, and will not interfere with operation of the gun, will not be liable to damage the roll or bundle during tightening of the tie- therearound, and will not impair the general appearance and feel of the applied tie. Figure, IB is a sectional view on the line B-B of Figure 1A , from which is apparent the lesser thickness of the bridging pieces 90 as compared to that of the tails 102 of the ties 100.

The ties 100 differ from the ties 10 previously described in that the buckle consists of a head 104 apertured at 106 transversely to the length of the tie 100, i.e. normally to the plane of the drawing in Figure lA .

The tie 100 is intended for use in the tie gun of Figures 6-12 which acts to push the tie forwardly around a nose loop closed around the roll or bundle to be tied so that the tail 102 re-enters the barrel of the gun to be threaded through the aperture 106 in the buckle 104, the latter being orientated at right angles to the re-entrant tail. Thus, for enabling the-tail 102 to be threaded through the buckle 104, the tie 100 when located in the gun is bent through 90 degrees adjacent the buckle, ^• thus appropriately orientating the buckle aperture 106. The bending of the tie 100 can be achieved by preforming the tie with its head portion bent through the required

90 . Then if the tie is packed flat (e.g. in a magazine) , on entering the gun the buckle springs into required orientation. Alternatively, a bending means may be incorporated in the gun, or as later described a bending means may be provided in the magazine from which the tie is supplied to the gun.

The construction of an individual tie 100 is shown in Figures 2A to 2D. Figure 2B is a central longitudinal section through the tie and Figure 2D is a section on line D-D of Figure 2A . The tail 102 has serrations 108 which engage with a pawl 110 formed on the inside of the aperture 106 in the buckle or head 104, so that the serrated tail can be threaded and advanced through the buckle to tension the tie around the roll or bundle to to tied, whilst said tail once . threaded cannot be pulled back through the buckle. It should be noted that as shown the serrations 108 are formed on the side of the tail 102 which will face in¬ wardly of the loop around the roll or bundle being tied, but the converse arrangement can be used if desired. It will also be clear from the drawings that the tail 102 of the tie 100 has untoothed ribs 112 along its edges, which ribs are accommodated in clear portions 114 of the aperture 106 in the buckle 104 to the sides of the pawl 110.

Figures 3 to 5 show a magazine for housing the bandolier 80 of Figure 1. The magazine 120 is formed of two parts 122, 124 hinged at 126, as indicated in Figure 3 , which shows the interior of the opened magazine when- empty. The shaped elongate mouth of the magazine 120, formed when the two parts 122, 124 are closed together, is referenced 128 in Figure 4 .

The closed magazine 120 is generally of cylindrical form but with a maximum diameter at an intermediate position 130 in its length generally

corresponding to the level of one end of the mouth 128. The magazine is shaped in this manner to receive a bandolier 8θ of ties 100 which is coiled spirally, with the adjacent turns of buckles in juxtaposed but not overlapping relationship. Thus, when the magazine is full, the one end of the spiral coil formed by a turn of buckles is accommodated at the bottom end 132 of the magazine as shown in Figure 4. As successive turns of buckles progressing up the coil are wound around an increasing number of tails, the diameter of the coil increases to a maximum at a level corresponding to the immediate position 130 along the magazine. This level is the level of the final turn of buckles; i.e. the outermost turn of the coil. The end of the bandolier 8θ emerges through the mouth 128 from this final turn. The upper part of the coil progressing towards the top end 134 of the magazine is constituted by a reducing number of tails, so that the coil gradually reduces in diameter. The mouth 128 of the" magazine is adapted to preform a 90 degrees bend in the tie 100, adjacent the head, as the tie emerges from the magazine into a tie gun to which the magazine is adapted to attach. The purpose of such bend in the tie is to pre-orientate the buckle in the gun ready to receive the tail, as previously described. In order to bend the tie, the mouth is formed with a series of five ribs, 13 , 138, 140, 142 and 144, as shown in Figures 4 and . While the tie 100 is emerging from the magazine, the ribs 136, 138, l4θ act on the head and adjacent portion of the tie to bend the head through 0 degrees relative to the length of the tail, the latter being held straight and flat by the ribs 142 and 144. The manner in which the 90 degree bend is formed in the tie 100 by the rib ^' s appears clearly from Figure A which is a section through

the mouth 128 near its exit. In Figure 5A, reference 146 denotes the passage traversed by a buckle, and reference 148 denotes the passage traversed by the bent portion of the tie adjacent the buckle. The rib 136 (not visible in Figure 5A) graduates away from the mouth exit to a shallower bend of greater radius, so that the bend in the tie is gradually developed as the tie progresses towards the mouth exit.

In practice, several ties 10Θ at the end of the bandolier 8θ will be following one another to emerge from the mouth 128, being suitably advanced by an indexing means in the gun to which the magazine is attached. The previously referred to knife means which acts to break off the bridging pieces will not be operative until the leading tie has emerged from the ■magazine, and in any event such nife means will be disposed on the remote side of the above-mentioned indexing means from the mouth of the magazine.

Figure 5B serves to show a pawl 150 provided within the mouth 128 of the magazine to prevent the bandolier 8θ from sliding back inwardly of the magazine. The ties 100 are drawn out over this pawl 150 to drop in front of it as the bandolier is indexed outwardly of the magazine. The gun shown in Figures 6 to: 12 will now be described, which gun uses the bandolier and magazine of Figures 1 tcj 5. The .tool has a casing 200 housing a longitudinally movable pusher rod 212, the construction of which is shown in Figures 9. The pusher rod 212 is con- nected through member 2l4 at the rear of the tool to the piston rod 2l6 of a (preferably pneumatic) cylinder/piston assembly, the cylinder being referenced by 218. A ^* trigger 220 is operable against the restoring action of a trigger spring 222 to actuate a change-over valve 224 thereby to drive the pusher rod 212 forwardly via the

piston 2l6 and connecting member 2l4. Additionally, a nose loop operating rod 226 is coupled to the rear of the tool through member 228 and pin 230 to the pusher rod 212. The nose loop 232 is normally urged closed by a torsion spring 23 (see also Figures 8 and 8A) , whereby the operating rod 226 is normally urged longitudinally in the forward direction.

During an initial part of the forward movement of the pusher rod 212, operating rod 226 follows in the forward direction under the action of the torsion spring 234. As indicated in Figure; 8, only a relatively small movement of a nose loop link 236 is necessary to complete closure of the nose loop 232. Following such nose loop closure, the member 228 separates from the stop pin 230 as the forward movement of the pusher rod 212 continues. Forward and rear guides for the nose loop operating rod 226 are indicated at 238 and 240. The member 228 also constitutes a valve change-over striker (see also Figure 10 ) , whereby a return longitudinal movement of the piston 2l6 is initiated at the end of its forward movement, so that at the end of an operating cycle the cylinder/piston assembly and changeover valve is restored to its original condition ready for further actuation by the trigger 220. In the direction of return movement of the pusher rod 212, the valve changeover striker 228 re-engages the nose loop enabling pin 230 towards the end of its rearward stroke, and in completing its stroke drives the operating rod 226 rearwardly to re-open the nose loop 232. In Figure 7 , reference 242 denotes a handle associated with the trigger 220, and reference 244 denotes a handle cover. The body of the changeover valve 224 is ^* located within the handle.

A prime purpose of the continued forward movement of the pusher rod 212, after the nose loop 23 has closed

e.g. around a bundle to be secured, is to drive a tie which has been entered into the tool around a channel defined between the closed nose loop and a bundle to be secured. Ties are entered from a magazine 248 (see also

Figure 11), in which a bandolier of ties is wound in a spiral helix of increasing diameter, as shown and described in Figures 1 to 5. During .each operating cycle, one tie is advanced into the tool from the magazine 248 and is severed from the bandolier. One such tie 250, having a head 252, is shown in Figure 7, in its position of initial insertion into the tool by advance from the magazine 248. It is to be noted that the tie 250 is bent through approximately ninety degrees at a point 25 adjacent its head 252, so that the aperture in the head is orientated in the longitudinal direction of the tool.

In order to effect indexing and'severing of the ties, the tool incorporates a longitudinally extending index bar256 (see also Figure 11) . This bar 25 is mounted for rotation against the action of a torsion spring 258 on spindle 26θ, under the drive of an index operating cam 262, which cooperates with a cam driving slot 264 in the push rod 212. The rod 212 drives the index bar 256 rotationally during the initial part of its forward movement, raising a shearing blade to cut an individual tie free from the bandolier. When the cam 262 is at full travel after this action it remains at full travel, its toe sliding along the side of the rod 212. Th index bar 256 is therefore not rotated during the latter p of the_.-forward ^" movement of the pusher rod 212.

Thus, when the pusher rod 212 continues its forward movement after closure of the nose loop 232, a tie 250 is already in its initial position in the tool. The front end of the rod therefore engages the head 252 of the tie, and pushes the tie around the closed nose loop.

During such forwards movement the end of the tie opposed to the head (the toe) is deflected downwards by a pair of opposed ramps 265, one of which is shown in Figure) 8 so as to enter a channel in the nose loop and pass right round the bundle. The front end of the rod pushes the head between two spring loaded combination head catching and tie cut off pawls, which will prevent any rearward movement of the head of the tie when the pusher rod commences its return stroke. Towards the end of the forward movement of the pusher rod 212, the tail of the tie emerges rearwardly from the nose loop to re-enter the front of the tool casing 210 in the rearward direction, in line with the apertured head 252, which it then enters. Further movement of the pusher rod 212 completes the stroke, pushing the head between the combination head catching and tail cut-off pawls and simultaneously engaging the tie tail toe teeth with sprag 302. The pusher rod 212 now reverses and commences its rearward movement, pulling the tie tail and leaving the head of the tie held by the combination head catching and tie cut-off pawls.

The rod 212 now draws back the tie tail, engaged between the sprag and the roof of the breech in the casing, drawing it through the head of the tie over the heads internal ratchet teeth. The tie body (tail) teeth thus engage both with the internal head teeth and the rod sprag teeth. This tensioning action pulls the tie body out from between the ramps 265 (Figure 8) ₁ the distance between the ramps having been carefully chosen to be just less than the tie body width so that downwards deflection of the toe occurs on forwards driving, but there is only moderate resistance to pull-out on tensioning 'This action tensions the bundle, and pressure builds up inside the cylinder. The body end of the cylinder is mounted to a rocking arm 268 by a mounting pin 272. The

^

rocking arm 268 is pivoted to the tool body by a pin 270, and retained by a notch cam 266 (attached to or formed integrally with arm 268) engaged by a spring loaded plunger 282. The increasing pressure in the cylinder 218 of the cylinder/piston drive, as the tie is tensioned, ^■ develops an increasing force on the cam 266 tending to cause said cam to release from the spring-loaded plunger 282. When the pressure in the cylinder 218 builds to a certain preset level, the cam 266 releases, thus causing the cylinder to drive the rocking arm 266 with a sharp, short movement into contact with the tie-cutting pawl device so as to sever the tail of the tie protruding through the apertured head. One or more air channels 278 enable ejection of cut-off tails from the tool.

The amount of tensioning applied to the tie 250 is adjustable by a tension adjuster 280 which comprises the indent plunger 282 engaging the cam 266 under the pressure of a detent compression spring 284. Adjustment of this adjuster 28θ alters the level to which the pressure in the cylinder 218 must build up before the cam 266 releases itself from the plunger 282.

Continued reverse movement of the pusher rod 212 allows the index bar cam 262 to re-enter the cam driving slot 264 in rod. 212, which action operates the index mechanism, lowering a cropping blade 308 (to be described later)ready for the next tie, and also advancing a fresh tie into the tool. There is a time lag between these steps, with the blade 308 being lowered first to open the breech before the next tie is advanced. The terminal part of the reverse movement of rod 212 drives open the nose loop 232.

Additional details of important parts of the tool mechanism are shown in Figures; 8 to 12. Figures 8 and 8A show details of the front end

of the tool including the nose loop assembly. In Figure 8 , the nose loop 232 is shown closed, with the open position in dotted line. In Figure 8A , the reference 286 denotes a nose loop pivot pin about which the nose loop is urged closed by the torsion spring 234. This pivot pin extends through a profiled front end 246 to the casing 210, (see Figure 7), which casing may conveniently be integrally made of moulded plastics material.

Figure 8 also shows a tie tail directing ramp, referenced 300, together with the sprag 302 and sprag compression spring 30 by means of which the sprag is urged into its tie tail holding condition when the tie tail arrives through the tie head, in the latter part of the forward stroke of the pusher rod 212. Figure 10 shows additional details associated with the changeover valve 224, including the relative positions of valve changeover striker 228, the nose loop enable pin 230, the pusher rod 212, the nose loop operating rod 226 and the cylinder 218. Reference 288' denotes a cylinder mounting spindle.

Figuresl 11 and 11A show details of the entrance region of the tool through which ties are advanced from th magazine 248. In Figure.il, reference 290 denotes the mouth of the casing 210 of the tool into which the magazine 248 is received. The exit of the magazine 248 has upper and lower lips 292, between which the leading end of a bandolier of ties housed in the magazine is drawn towards the tool. These lips 292, 294 m be formed as integral parts of the plastics moulded magazine. A bearing post 29 supports the adjacent parts of the indexing mechanism, including the frontend of the index bar 256 on spindle 26θ. The index bar 256, driven ^• by an index operating cam 298 during the continued reverse stroke of the pusher rod after tensioning and cutting of one tie, moves an index finger 206 which engages the

leading tie (disposed lengthwise perpendicular to the plane of the drawing) of the bandolier to advance it into the tool. Instead of the mouth of the magazine being profiled to bend the tie adjacent its head through approximately ninety degrees, for the tie to assume the condition of the tie 250 shown in Figure 7 , in the tool shown the mouth of the tool itself is profiled to bend the tie.

Figure 11A shows the cropping mechanism by which the leading tie, having been indexed into the mouth of the tool during the preceding reverse stroke of the pusher rod, is severed from the bandolier during the next forward stroke of the pusher rod prior to engagement of the front end of the latter with the head of the tie. A cropping blade 308 is mounted on a pair of rocking levers 310 and is tensioned downwards by a spring 312 (see also Figure ¹ 7 ) . The cropping blade rocking levers 3 0 are operable by*toe rollers 3 carried with the index bar 256, the latter driven under its cam drive previously referred to.

Finally, Figures 12 -12A and.12B show details associated with the tie tensioning and cutting mechanism. Figure 12B shows the mounting 272 of the cylinder 2l8 to the rocking arm 268, which is pivotally mounted to the casing on spindle 270. Reference 3 6 denotes ^' a support block for the index plunger 282 previously described.

Referring now to Figures.12 and.12A , the tie- cutting pawl device comprises a pair of cut-off pawls 31S connected to pawl links 320 which are primarily tensioned by spring 3 2. A pivot pin for the linkage is referenced 324 in Figure 12A . Certain other details -of this part of the mechanism appear in Figure 6 , including a pawl stop plate 326, the support block 328 for the adjuster and a pair of spring blades 330. The pawls 318 are held partly open by blades 330 against tension spring 322 to enable

the tie to pass through. The head passes through irst, when the pawls half close, then at the desired tension the rocking arm 268 is released. When the rocking arm is released from cam 266, a cam 269 on said arm 268 strikes the pawl linkage to sever the tail of the tensioned tie. Each pawl includes a ^' post portion 318^ mounted for rotation about its own axis and having the blade 3l8b projecting radially from its lower end, and a limb 318^ projecting radially from its upper end to the respective link 320. The springs 33° bear against the outer surfaces of the limbs 3l8^ near the rear ends of the latter.

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