EP0616873B1 - Screwdriving tool for screws connected by a strip - Google Patents

Description

The invention relates to a screwdriver for taped screws according to the preamble of claim 1.

From DE-OS 26 41 828 it is known to process taped screws with a portable screwing device provided with a magazine. A plastic connecting strap is used to hold the screws, the shafts of the screws being encompassed by loops of the connecting strap.

The screw strip is moved in the direction of the screw blade by means of a conveying device and during the screwing-in process the screw to be screwed in is released from the connecting belt, the loop being torn open. However, parts of the connecting belt can get between the screw head and the workpiece surface when screwing in, which is particularly disruptive for sensitive workpieces.

The object of the present invention is therefore to provide a screwing device of the type mentioned, in which the screw is separated from the connecting belt safely and without residues during the screwing-in process.

This object is achieved by the feature specified in the characterizing part of claim 1.

The complete separation of the connecting belt from the screw to be screwed in by the lifting element according to the invention ensures that the screw is screwed into the workpiece unimpeded and without entrainment of parts of the connecting belt.

This is particularly advantageous in the case of screws with large head diameters or with underlying sealing washers, the lifting element pivoting the connecting belt out of the screw-in path of the screw to such an extent that it is not hindered when screwing in. This guarantees a perfect and straight screwing.

Advantageous developments of the invention are characterized by the subclaims.

An exemplary embodiment of the invention is described in more detail below with reference to the drawings.

Fig. 1

Lagerkörper eines Schraubgeräts, von der Seite, teilweise geschnitten

Fig. 2

Schnitt nach Linie II - II in Fig. 1

Fig. 3

Schnitt nach Linie III - III in Fig. 1, Abhebeorgan in Ruhestellung

Fig. 4

wie Fig. 3, Abhebeorgan in Abhebestellung

Fig. 1 zeigt den Lagerkörper 1 eines Schraubgeräts, dem aus einem nicht dargestellten Magazin die zu einem Schraubenstreifen 2 verbundene Schrauben 3 mittels einer Fördervorrichtung 4 zugeführt werden. Zum Halten der Schrauben 3' dient ein Verbindungsgurt 5 aus Kunststoff (siehe auch Fig. 3), dessen Halterücken 6 mit Schlingen 7 versehen ist, die den Schaft 8 von Schraube 3 umfassen. Diese Schraube 3 ist weiterhin mit einer unter ihrem Kopf 9 aufgesteckten Dichtscheibe 10 versehen, deren Durchmesser wesentlich größer ist als der Durchmesser von Schaft 8.Show it:

Fig. 1

Bearing body of a screwdriver, partially cut from the side

Fig. 2

Section along line II - II in Fig. 1

Fig. 3

Section along line III - III in Fig. 1, lifting element in the rest position

Fig. 4

as Fig. 3, lifting element in the lifting position

1 shows the bearing body 1 of a screwing device, to which the screws 3 connected to a screw strip 2 are fed from a magazine (not shown) by means of a conveying device 4. A plastic connecting strap 5 is used to hold the screws 3 '(see also FIG. 3), the holding back 6 of which is provided with loops 7 which secure the shaft 8 of the screw 3 include. This screw 3 is further provided with a sealing washer 10 which is plugged under its head 9 and whose diameter is substantially larger than the diameter of the shaft 8.

In the bearing body 1, a guide channel 11 is provided for the screw strip 2, which opens into a guide bore 12. This is aligned with a bearing bore 13 for the screw blade 14, so that the first screw 3 'of screw strip 2 is also aligned with the screw blade 14.

The screw blade 14 can be driven by an indicated electric motor 15, when the screw 3 'is screwed into the workpiece 16, the shaft 8 of the screw 3' is guided by an elastic centering funnel 17.

2 and 3 in particular, a lifting member 18 is pivotally mounted in the bearing body 1 at the end of the guide channel 11, its pivot axis 19 being arranged inclined to the guide bore 12. In the rest position of the lifting element 18 shown in FIG. 3, a form spring 20 presses it against a stop surface 21 of the bearing body 1.

The lifting element 18 is essentially angled, the free holding back 6 ′ of the connecting belt 5 being pushed in front of a leg 22 of the lifting element 18. This also has an inclined and curved contact surface 23 directed against the guide channel 11 and a prismatic centering surface 24 parallel to the guide bore 12.

The function of the lifting element 18 is assumed to be in its rest position shown in FIGS. 1 and 3. After switching on the electric motor 15, it sets the screw blade 14 in rotation and this is moved in the direction of the workpiece 16 by pressing the electric motor 15 in the bearing body. After the head 9 of the screw 3 'has been reached, this is also set in rotation, the connecting belt 5 being displaced by the thread of the shaft 8 shown in the loop 7 counter to the direction of advance of the screw 3 becomes. It is prevented from further movement by a stop surface 25 of the lifting element 18, so that the loop 7 tears open and the connection between the screw 3 'and the connecting belt 5 is released.

The sealing disk 10 now touches the contact surface 23 of the lifting element 18 and pivots it clockwise, it reaching the lifting position shown in FIG. 4. Thus, the leg 22 of the lifting member 18 takes the free end 6 'of the holding back 6 and pivots it out of the screw-in area of the screw 3', so that it can be screwed into the workpiece and guided by the centering funnel 17 perpendicular to the surface of the workpiece 16.

During the screwing-in process, the conveying device 4 is tensioned in a known manner, so that after the return of the screw blade 14 to its rest position, the lifting element 18 returns to its rest position under the action of the shaped spring 20 and the screw strip 2 is displaced in the direction of the guide bore 12 until the next screw 3 is aligned with the screw blade 14, its shaft 8 striking against the centering surface 24 of the lifting element 18.

Claims (8)

1. A screwdriving unit for belt-fed screws having a bearing element in which a drivable screw- driver blade is movably mounted, having a guide channel vertical thereto for the screws linked up to a screw strip by at least one connecting belt, having a conveying device for said screw strip, and having a guide hole for the screw to be screwed in, characterized in that a movable lift-off element (18) is provided in said guide channel (11) in the area of said guide hole (12) and is actuatable transversely to said guide channel (11) such that it lifts said connecting belt (5) off said screw (3') to be screwed in.
2. A screwdriving unit according to Claim 1, characterized in that said lift-off element (18) interacts with the free end of said connecting belt (5).
3. A screwdriving unit according to Claim 1 or Claim 2, characterized that said lift-off element (18) is actuatable by said screw (3') to be screwed in.
4. A screwdriving unit according to one of Claims 1 to 3, characterized in that said lift-off element (18) is pivotably mounted in said bearing element (1).
5. A screwdriving unit according to Claim 4, characterized in that the swivel axis (19) of said lift-off element (18) is disposed inclined in relation to said guide hole (12).
6. A screwdriving unit according to one of Claims 1 to 5, characterized in that said lift-off element (18) has an inclined contact surface (23) oriented towards said screwdriver blade (14).
7. A screwdriving unit according to one of Claims 1 to 6, characterized in that said lift-off element (18) has a centering surface (24) for said screw (3') oriented towards said guide channel (11) and parallel to said guide hole (12).
8. A screwdriving unit according to one of Claims 3 to 7, characterized in that said screw (3') has in its head portion (9, 10) a considerably larger diameter in relation to the shank (8) and in that said lift-off element (18) is actuatable by said head portion (9, 10).

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