The present invention relates primarily to a method for loading the fastener dispensing chamber of a lashing machine, stapling gun or like apparatus with continuous and coherent strips of U-shaped fastener elements or like fasteners, in which chamber each strip is advanced by the action of a spring force, such as to bring one fastener at a time into a working position in which said fastener element can be stripped from the remainder of the strip by a fastener activating device. The invention also relates to a magazine for use when practicing the method, and to a fastener case intended for use in said magazine.

Almost all known stapling devices intended for driving staples or like U-shaped fasteners into a εub- ^: strate comprise a combined magazine and fastener dis¬ pensing -Chamber which is intended to receive a con¬ tinuous strip of staples or like fasteners. When it is desired to increase the capacity of such a device, the device has to be lengthened, so that it can accommodate a longer strip of staples. This can be disadvantageous in many instances.

WO 88/01671 describes a novel type of lashing machine intended, inter alia, for use on building sites, for the purpose of lashing together concrete reinforcement rods prior to casting a concrete structure. This machine enables concrete reinforcing rods to be lashed together quickly and simply, with the aid of automatically advanced U-shaped wire ties. The ties are placed over the intersection points of the reinforcing rods and the

legs of the ties are subsequently twisted together beneath the rods, with the aid of a twisting or lashinσ

K : i head. }

'! This known apparatus also utilizes a magazine containing a large number of U-shaped fastener elements, or wire ties, joined together to form a continuous fastener strip, which is advanced incrementally, such as to bring one fastener at a time into a precise, desired working position. The magazine consequently has a long, narrow configuration and, if it is to contain a large number of ties or fasteners, will extend laterally fror. the ma¬ chine over some considerable distance. This restricts the usefulness of the apparatus to some exte t and the apparatus also becomes more susceptible to damage when subjected to rough treatment on the building site, such treatment being quite common in these contexts.

The present invention is based on the concep- that the aforesaid problems can be eliminated, or at least sub¬ stantially reduced, if the magazine were to be extended vertically, when desiring a large magazine capacity. Such a modification, however, would require the pro¬ vision of a solution to the problem of feeding fastener strips vertically into the fastener dispensing chamber, one strip at a time, susequent τ.o preceding fastener strips being consumed. Since each strip will preferably only include a relatively small number of wire fasteners in order to keep the lateral dimensions of the apparatus within suitable limits, which implies tha the apparatus will need to be reloaded at relatively frequently inter¬ vals, it must be possible to load the fas ener dispensing chamber in a simple and quick fashion.

Accordingly, there is proposed, in accordance with the invention, a method of i-he aforesaid kind which is characterised by placingi'each fastener strip in a separ¬ ate case provided with a withdrawable bottom; stacking a plurality of such cases on top of one another, with the lowermost case located over an infeed opening in an upper defining surface of the fastener dispensing cham¬ ber; withdrawing the bottom of the lowermost case, so that the fastener strip resting thereon will fall down into the fastener dispensing chamber; and then removing the empty case, so that the next case in line is positioned above said infeed opening.

The invention thus enables a very large number of fasteners to be stored in the magazine, and the storage of fastener strips in individual fastener cases enables fastener strips to be charged one at a time to the fastener dispensing chamber of the apparatus. The fastener cases also function to protect the fastener against damage, e.g. protect the fastener legs from against buckling before leaving the machine, which is a prerequisite for the problem-free functioning of the machine.

In accordance with one preferred embodiment of the invention, a withdrawable closure plate is provided between the infeed opening and the bottom of the lower¬ most fastener case, and means are provided for locking the closure plate to the withdrawable bottom, so that said bottom will accompany the plate as it is withdrawn from the vicinity of the infeed opening.

The provision of such a closure plate will therefore facilitate the withdrawal of the bottoms of respective fastener cases. In addition, the closure plate will also

serve as a cover plate which covers the infeed opening while the machine is in active use, thereby preventing fasteners from being pressed up through the inlet open¬ ing by the spring force utilized to advance the fasteners in the fastener dispensing chamber.

The bottoms of respective fastener cases are preferably locked to the closure plate with the aid of mutually coacting guide members, which are brought into locking engagement with one another as the fastener case con¬ cerned is fed down onto the plate. In addition to guid¬ ing respective fastener cases effectively into position, with the fastener strip correctly aligned for insertion into the fastener dispensing chamber, appropriate con- figuration of the guide member located on the closure plate will also prevent the unintentional use of fas¬ tener cases that are loaded with fasteners different to the fasteners for which the apparatus is intended.

The invention also relates to a magazine for use when practicing the inventive method and to a fastener case intended for said magazine, the essential characteristic features of which magazine and fastener case are set forth in the following appropriate claims.

The invention will now be described in more detail with reference to the accompany drawings, in which Figure 1 illustrates a known lashing machine equipped with a magazine constructed in accordance with the invention;

Figure 2 is an enlarged view of the magazine and the underlying fastener dispensing chamber; Figure 3 illustrates the __mutual coaction between a fastener case and a closure plate included in the maga- zine shown in Figure 2;

Figure 4 is a vertical sectional view of the lower part of the magazine and the fastener dispensing chamber according to Figure 2, with the closure plate in its closed position; and Figures 5A-E illustrate the different stages of loading the fastener dispensing chamber located beneath the magazine.

The lashing machine illustrated in Figure 1 includes an elongated shaft 1 which carries a handle 2 at one end thereof and a tying or lashing head 3 at the other. The reference numeral 5 identifies an operating lever or handle which controls a mechanism 4 operative to feed U- shaped wire ties to the point of mutual intersection of reinforcing rods 6 and 7 located above the lashing head 3. The wire ties are discharged and separated from a continuous strip of mutually joined wire ties positioned in an fastener dispensing chamber 9, with the aid of a vertically moveable dispenser plate 1C. The legs of the respective ties 8 protruding beneath the reinforcing rods are gripped by the lashing head 3 and twisted around one another as the head rotates, therewith to lash the rods together. The tie twisting head is povered by an electric motor not shown. Up to this point, the described lashing machine coincides exactly with the lashing machine described and illustrated in the afore¬ said publication WO 88/01671, and will not be described in further detail here.

For the purpose of restricting the length of the fas¬ tener dispensing chamber 9, and therewith also the extent to which it extends sideways relative to the remainder of the machine, while still enabling the machine to magazine a large number of U-shaped wire fasteners, it is proposed in accordance with the inven-

tion that the fastener dispensing chamber is combined with a vertical magazine 11 in which strips of fasteners can be stored for sequential feeding into the fastener dispensing chamber 9 of the machine. This will enable a very large number of fasteners to be stored in readi¬ ness, without requiring the chamber to project exces¬ sively from one side of the apparatus. Such extension of the chamber would restrict the usefulness of the machine in practice and would also render the machine more liable to damage from external sources, as before mentioned.

Figure 2 illustrates, in larger scale, the magazine 11 incorporated in the lashing machine shown in Figure 1, and illustrates the fastener dispensing chamber 9 lo¬ cated beneath the magazine, said chamber being empty in the illustrated view. The magazine comprises a box-like casing 21 which is connected to the fastener dispensing chamber 9 and which has a closeable door 12. The lower part of the door 12 includes a vertically diεplaceable plate 13. In the case of the illustrated embodiment, the box-like casing 21 has stacked therein six fastener cases or boxes 14, each of which contains a strip of U- shaped wire fasteners 8. The lowermost fastener case 14, nearest the fastener dispensing chamber 9, rests on two support flanges 15.

The output chamber 9 includes an inner guiding and supporting member 16, over which a strip of fasteners 8 can be advanced against a stop wall 17, see Figure 4 which shows the chamber loaded with fasteners, such that one fastener at a time is located in a slot-like space in front of the stop wall 17. The fastener located in said space can be separated from the remainer of the fastener strip by means of the dispenser plate 10, which

when executing a working stroke slides down the rear wall of the magazine 11. The fastener strip is advanced against the stop wall 17 by means of a pushing device 19 activated by a spring 18. The reference numeral 20 identifies a hand grip by means of which the pushing device 19 can be retracted, so as to enable a fresh fastener strip to be introduced into the fastener dis¬ pensing chamber 9, when the preceding strip has been consumed. Figure 2 illustrates the fastener dispensing chamber in readiness for charging said chamber with a fresh strip of fasteners. Means are preferably provided for locking the pushing device temporarily in the posi¬ tion shown in Figure 2, during a chamber loading opera¬ tion.

Each fastener case 14 can be made of an inexpensive plastics material and is constructed to accommodate a fastener strip comprising a plurality of mutually con¬ nected U-shaped wire fasteners, e.g. 40 such fasteners. The fasteners can be joined together by means of a bonding substance, a varnish, ^"' a ^' thin plastic foil or the like. In addition to being pulled downwards by the action of their own weight, the fastener cases are pressed down, vertically, by a spring 22. Each fastener case 14 is provided with a withdrawable bottom 23, on which respective strips of fasteners 8 rest. Arranged between the withdrawable bottom 23, of the lowermost fastener case 14 and an infeed opening 24 provided in the upper defining surface of the fastener dispensing chamber 9 and located beneath the bottom 23 is a laterally withdrawable closure plate 25.

As illustrated in Figure 3, the closure plate 25 is provided with an upstanding guide member 26 which is intended to engage a correspondingly, inwardly directed

guide member 27 provided in the bottom plate 23 of the nearest overlying fastener case 14. The guide members 26 and 27 are intended to guide the lowermost fastener case 14 into its correct position relative to the closure plate 25, so that the fastener strip located in said case will be correctly oriented in relation to the guiding and supporting member 16 in the fastener dis¬ pensing chamber 9. The guide members 26, 27 will also be effective to lock the withdrawable bottom 23 to the withdrawable closure plate 25, such that the bottom 23 will accompany the closure plate 25 as said closure plate is withdrawn.

The method of operation of the magazine will now be described with reference to Figure 5, which illustrates schematically the fastener dispensing chamber 9 and the two lowermost fastener cases 14 in the magazine, during various working stages. Figure 5A illustrates the work¬ ing state shown in Figure 2, in which the fastener dispensing chamber 9 is empty and the fastener case 14 located above the infeed opening in the upper defining wall of the fastener dispensing chamber is filled with a strip of fasteners 8. The closure plate 25 is then withdrawn, resulting automatically in the withdrawal of the bottom 23 of the fastener case 14. As a result, the fastener strip in the fastener case 14 will fall into the fastener dispensing chamber 9, see Figure 5B. In order to ensure that the strip is guided correctly into the fastener dispensing chamber 9, the guiding and supporting member 16 provided in said chamber has a slight conical taper in the upward direction, as illustrated in the figure.

Subsequent hereto, only the closure plate 25 is returned to its original position, see Figure 5C, there being no

obstacle to movement of the guide member 26 on said plate. This plate also [fupctionε to press down the fasteners 8 located in e fastener dispensing chamber 9 and prevents the fasteners from being pressed up through the infeed opening 24 by the spring-loaded pushing device 19.

In the next stage of operation, the now bottomless, empty fastener case 14 is withdrawn from the stack. This withdrawal is effected by lifting the vertically move- able hatch plate 13 in the lower part of the door 12, without opening the door. This feature is illustrated in Figure 5D. Subsequent to removing the empty fastener case, the next, overlying fastener case 14 in line, containing a fresh strip of fasteners 8, will fall down into the position previously occupied by the removed, empty fastener case, see Figure 5E, with the remaining fastener cases in the stack dropping to the same extent. The cycle, can- then be repeated, when the fastener diε- pensing chamber 9 haε again been emptied.

The aforedeεcribed method enableε freεh εtripε of faε- tenerε 8 to be loaded into the faεtener diεpenεing chamber 9 in an extremely simple fashion, each of said fastener strips being handled while enclosed in..ah individual fastener case 14. The fastener case also functionε to protect the U-εhaped wire faεtenerε during shelf-storage, transportation and storage on the working site. The legs of such U-shaped wire faεtenerε are readily bent prematurely, and it will be underεtood that premature bending of said legs would render the use of such fasteners in automatic lashing machines impossible and result in serious interruptions in operation. The fastener cases also protect the fastener stripε againεt dirt and other influenceε likely to jeopardize the

function of the lashing machine.

Due to the accurate positioning of respective fastener cases 14 relative to the fastener dispensing chamber 9 by means of the closure plate 25 and the configuration of the guide and support member 16 in the chamber 9 it is guaranteed that the fasteners 8 are positioned cor¬ rectly in the fastener dispensing chamber, which is a prerequisite for the reliable functioning of the appa¬ ratus. Because the bottom member 23 of respective fastener cases 14 is withdrawn through the intermediary of the closure plate 25, it is not necessary to provide said bottom members with projecting gripping devices or the like which is an important advantage. Although the above description is concerned with one particular embodiment of an inventive magazine, it will be understood that this embodiment can be modified and changed in several respects within the scope of the following claims. For instance, the number of fastener cases capable of being accommodated by the magazine can be chosen in dependence on desired magazine capacity. The mutually coacting guiding and locking members pro¬ vided on the closure plate 25 and the bottoms 23 of said fastener cases can also be modified as desired, for in¬ stance such as to enable a given type of fastener case to be used solely with given machines therewith, for instance, preventing the use of fastener cases which contain fasteners of the wrong quality or dimensions. The guiding and locking members of the illustrated embodiment have the form of mutually coacting male and female devices. It will be understood, however, that several such guiding and locking members may be pro- - vided, if so desired, and located at positions different to those shown. It is preferred, however, to position these members such that the bottoms of respective fas- tener cases will be flat.