The present invention relates to a supplementary unit for a portable fastener driver assembly, such as a nailing gun, comprising a reciprocatingly movable percussion device at its active end.

When laying sheet-metal roofs using conventionally rebated roofing sheets, the sheets have been secured to the underlying roof structure in recent times with the aid of fasteners in the form of profiled nail plates, by means of which the upwardly facing rebate flanges of the roofing sheets can be anchored to the underlying roof structure without needing to perforate the sheets in the anchoring process. The work involved in driving the nails of ther nail plate through the roofing sheets manually is extremely time-consuming.

The object of the present invention is therefore to provide a supplementary unit for a portable fastener driving assembly of the kind defined in the introduction which is able to greatly reduce the time taken to drive profiled nail fasteners through such roofing sheets, particularly fasteners in the form of profiled nail plates.

This object is achieved with the characteristic features set forth in the following claims 1.

According to one aspect of the invention, the supplementary unit includes an elongated percussion unit whose one end can be connected to the active end of the fastener driving assembly, and whose other end communicates with a magazine for nail-plate fasteners and presents an outfeed opening for fasteners advanced from the magazine, wherein the percussion unit includes a reciprocatingly movable fastener driving element which is activated by said percussion device. This enables the working range of the practical

nailing gun to be extended to include nail-plate fasteners. The lengthening of the nailing gun caused by the supplemen¬ tary unit is beneficial, since it enables the workman to work at a comfortable height when working on substrate surfaces such as roof structures.

Mounted in the outfeed opening is a resiliently yielding device which functions to grip opposing edge parts of a fastener advanced to the outfeed opening and holds the fastener firmly therein. This ensures that the fasteners will be held safely and not fall unintentionally from the outfeed opening.

When the percussion element or fastener driving element includes a pair of percussion devices that are mutually spaced in the transverse direction, the fasteners can be placed tightly packed against one another and may partially overlap one another in the magazine, so that a forwardly projecting part or holder means of that fastener element which immediately follows the preceding advanced fastener element to be driven from the gun is free from the fastener driving element as the preceding fastener is driven from the gun.

When the outfeed opening at the other end of the percussion unit not only extends continuously over an area of said end but also over an area on the side of the percussion unit that lies opposite to the magazine, this latter area extending generally at right angles to the first-mentioned area, it is then possible to drive the fasteners into abutment with the flange of the roofing sheet to be anchored.

Other features of the invention and advantages afforded thereby will be apparent from the remaining Claims and also from the following detailed description of an exemplifying embodiment of the invention.

The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a schematic side view, partially in section, of an inven¬ tive supplementary unit fitted to a nailing gun; Fig. 2 is a front view, partially in section, of the supplementary unit shown in Fig. 1, with certain parts cut away; Fig. 3 is a view from beneath of part of a known nailing gun; Fig. 4 is a view corresponding to Fig. l and shows an underpart of an inventive supplementary unit in larger scale; Fig. 5 is a perspective view of a fastener intended for use with the supplementary unit; Fig. 776 is a detailed view of an alternative arrangement for holding the fastener elements in an outfeed opening; and Fig. 7 is a sectional view taken on the line 7-7 in Fig. 6.

Fig. 1 illustrates a portable fastener driving assembly generally referenced 10, to which there is fitted an inventive supplementary unit comprising a percussion unit 30 and a fastener magazine 80.

The illustrated embodiment of the fastener driving assembly is a typical, commercially available nailing gun 10, for instance of the type which includes a hammer mechanism (not shown) which is driven reciprocatingly by gas combustion and which advances and retracts an elongated, flat percus¬ sion device 14 at the active end 12 of the gun. Also extending from the active end of the gun is a holding and guiding unit 16 which is connected firmly to the gun 10 and which includes a pair of mutually parallel and sloping bores 18, 18 located on respective sides of a nail guide passage 20. In the normal use of the nailing gun, the holding and guiding unit 16 is intended to be connected to a nail magazine, for advancing nails to the guide passage 20, from where the nails are driven into an underlying surface with the aid of the percussion device 14. Although not shown, the known nailing gun is normally provided with

a battery holder disposed parallel with and forwardly of the illustrated handle 22.

The inventive supplementary unit is intended to be connect- ed detachably to the holding and guiding unit 16, in a manner corresponding to the known nail magazine. More specifically, an upper end-part of the housing 32 of the percussion unit 30 is provided with a pair of obliquely and forwardly projecting holder pins 34, 34 which are intended for insertion into the bores 18. The magazine 80 connected to the percussion unit 30 is then connected to the nailing gun 10 at the free end of its handle 22, with the aid of a screw or pin connection 82. The supplementary unit is therewith firmly and securely attached to the gun 10.

The percussion unit 30 has arranged therein a percussion element 36 which has a fork-shaped engagement end and presents a pair of percussion ends 38 which are mutually spaced in the transverse direction, and a shaft 40 which is common to said percussion ends 38 and connected thereto. That part of the shaft 40 which lies proximal to the nailing gun is mounted for sliding movement between the holding and guiding unit 16 and the inside of the defining wall of the housing 32, while that part of the shaft which is located proximal to the percussion ends 38 is slidingly mounted in a guide body 42. The guide body 42 is firmly connected to the unit 16 by an elongated attachment element 44. A spring, which in the illustrated case, has the form of a pulling coil spring 46 mounted between the forked-part of the percussion unit 30 and the guide body 42, ensures that the percussion element 36 will constantly strive to take a retracted or withdrawn position in the percussion unit 30, as illustrated in Fig. l.

In this position, the free end of the longitudinal part of the shaft 40, this part being partially let into the unit 16, is exposed to the free end of the percussion device 14

of the nailing gun 10 and is in a stand-by position to drive it forwards.

The magazine 80 connected to the percussion unit 30 includes an internal passageway 84 whose internal open cross-section is adapted to the fasteners 110 (Fig. 5). Arranged within the passageway 84 is a known feeder 86 which includes a band-like coil spring 88 which has one outer end connected to an upper front edge of the magazine 80 and the other, inner end connected to a central axle within the feeder 86, such that the spring 88 will strive to move the feeder 86 in the passageway 84 towards the outlet orifice thereof in the percussion unit 30.

The magazine 80 can be filled with fasteners 110 in different ways; for instance, the open bottom of the magazine may have a widened part (not shown) at the rear edge of the magazine 80, so that fasteners 110 can be inserted singly into the magazine. In the case of the illustrated embodiment (Fig. 2), the magazine 80 is comprised of an upper and a lower half, wherein the lower half can be swung out around the upper half on a pivot axle 90 located at the front edge of the magazine 80, thereby enabling fasteners, which may be contained in a pre-pack, can be inserted into the magazine after retracting the feeder 86, which may also be hooked firmly (not shown) to a rear end of the magazine.

As will be seen in particular from Fig. 2 when taken together with Fig. 4, the percussion unit 30 and the magazine 80 are mutually joined on the underside of the supplementary unit by means of a right-angle abutment piece 92 which forms a support against an underlying structure 120 into which fasteners 110 are to be driven, while also supporting against the outer surface of the upstanding flange 124 of the roofing sheet 122 to be secured to the underlying structure 120. The

angled abutment piece 92 includes two right-angled continu¬ ously extending fastener outfeed openings, more particular¬ ly an opening 94 which faces towards the underlying structure 120 and an opening 96 which faces towards the flange 124 of the roofing sheet 122.

Mounted on each of the opposite inner surfaces of the opening 94 is a resiliently yielding device in the form of a leaf-spring 100 which is configured as the first part of an S, for instance, and which extends into the opening 96 and engages a bordering side edge of the fastener located in the opening 96, so as to prevent the fastener from falling unintentionally from the opening 96 should the supplementary unit be subjected to an external force, such as a blow or knock. As will be evident from Fig. 4, the fastener located in the opening is also held by the friction generated between abutment pieces 98, 98 (de¬ scribed below) and the nail legs 118 of the fastener element next in line in the magazine 80.

The aforesaid abutment pieces 98 are mounted at a given height on each side of the opening 96 on the outer side of the vertical part of the angled abutment piece 92, and said abutment pieces 98 extend partially into the opening 96 and their inner surfaces form supports for the outer parts of the upstanding flange 112 of the fastener 110 that is in position to be driven into the underlying structure. The outside of the flange 112 is, in this way, brought automat¬ ically into line with the bordering or adjacent outer surface of the upstanding flange 124 of the roofing sheet 122 prior to driving-in the fastener. The remaining opening between the abutment pieces 98, 98 provide free passage to a holder 116 connected to each fastener and intended to engage the angled upper side of the upstanding flange 124 of the roofing sheet 122, so as to anchor the sheet 122 as the fastener 110 is driven into the sheet.

The inventive supplementary unit fitted to the nailing gun is intended to operate in the following manner:

The abutment piece 92 of the supplementary unit is placed against the underlying structure and against the outer surface of the upstanding flange 124 of the roofing sheet 120. When the trigger 24 of the nailing gun 10 is activat¬ ed, the percussion device 14 is propelled forwards and strikes the percussion element 36, which is thereby accelerated down in the housing 32, whereafter the mutually spaced percussion ends first pass the holder part 116 of the next following fastener 110 projecting between said percussion ends and strike the upper side of the fastener 110 standing first in line at the regions of the two downwardly bent nail legs 116 of the fastener 110, so that said legs are driven into the underlying structure 120 together with the fastener, close into the flange 124 of the roofing sheet. The percussion element 36 is then retracted by virtue of the spring 46 while the feeder 96 feeds the next following fastener 110 from the magazine to the place previously occupied by the newly driven fastener. If the nailing gun is of the kind which, for safety reasons, must be activated by retracting the percussion device 14 slightly prior to driving in the next fastener, this can be ef ected in dif erent ways, for instance by retracting the percussion element 36 towards the percussion device 14.

Figs. 6 and 7 illustrate an alternative arrangement for resiliently holding a modified fastener 130 firmly in the outfeed opening of the supplementary unit. In this case, the upstanding flanges 132 of the fasteners 130 are somewhat shorter than their bottom part 134, such that said bottom part will present forwardly projecting opposite end- edges 136 (only one of which is shown in Fig. 6). Each projecting end-edge 136 is accommodated in the outfeed opening in a groove defined by a bottom corner recess 148

of a guide piece 144, and one end of a leaf spring 140 which projects into the recess and lies against the underside of the guide piece 144. The leaf spring 140 is secured to the underside of the guide piece by means of a screw 142. The corner recess 148 in the guide piece 144 is widened at that end which lies proximal to the magazine 80 (not shown), as indicated at 146, so as to facilitate delivery of fasteners 130 into the outfeed opening. As indicated in broken lines in Fig. 6, when driving a fastener 130 the fastener will bend the leaf spring 140 outwards until the free end of the spring is able to pass the outwardly jutting end-edge 136, so as to release the fastener 130 therefrom. The fasteners are held more securely in the case of this alternative arrangement, prior to being driven into the underlying structure.