EP3825064A1 - Method for screwing a self-tapping concrete screw - Google Patents

Abstract

For screwing a concrete screw (2) into a screw hole (3) in concrete (4), the invention proposes a rotary drive tool (1) with a socket (6) in a tubular clutch release (8) which, when it hits a locking ring ( 11) inside the clutch release (8) disengages the socket (6) from a screw head (5) of the concrete screw (2) and thereby terminates the screwing in.

Description

The invention relates to a method for screwing a self-tapping concrete screw into a threadless screw hole in concrete with the features of claim 1. Self-tapping concrete screws are - normally with the help of a pneumatic or electric impact screwdriver - screwed into a, for example, drilled, cylindrical screw hole in concrete, whereby the concrete screws cut a mating thread in the screw hole itself.

For the reinforcement of load-bearing structures made of concrete, for example a carriageway body of a bridge, it is known that an additional concrete layer is applied to this structure. The concrete layer typically has reinforcement and is used in particular to carry away an increased bending load in the sense of a higher load-bearing capacity of the structure. So that there can be a transmission of force, in particular a transmission of shear forces, between the structure and the new concrete layer, a large number of concrete screws are often screwed into the structure. The concrete screws are not screwed in completely, but in such a way that the screw head clearly protrudes from the structure. The subsequently applied concrete layer can thereby encompass the screw head and the concrete screw can transfer forces between the structure and the new concrete layer. In order to achieve a specific distance between the screw head and the structure, it is conceivable that the holes for the concrete screws are only drilled so deep, for example via a stop on the drill, that the concrete screws touch the bottom of the hole when the desired position is reached. However, this harbors the risk that the concrete screws, when they reach the bottom of the borehole, are loaded with such a strong torque that either the concrete screw or the internal thread grooved by the concrete screw in the concrete is damaged.

The object of the invention is to propose a method for screwing a self-tapping concrete screw into concrete with a fixed protrusion of the screw from the concrete and a fixed distance of a screw head from the concrete.

This object is achieved according to the invention by the features of claim 1. The method according to the invention uses a rotary drive tool with a form-fit coupling and a clutch release. The form-fit coupling has, for example, a hexagon socket, such as a pipe wrench or a socket, to match a hexagon screw head of the concrete screw. Other form-fit couplings, suitable for a different screw head, are possible. The form-fit coupling can be attached non-rotatably to the screw head of the concrete screw by means of a form-fit connection, so that the screw can be driven to rotate by rotating the form-fit coupling.

The clutch release mechanism ensures a (minimum) distance between the form-fit coupling and the concrete with the screw hole into which the concrete screw is screwed. The distance can be fixed or adjustable.

To screw the concrete screw into the screw hole in the concrete, the form-fit coupling is attached to the screw head of the concrete screw in such a way that it is rotationally fixed to the screw head by means of a form fit. The screw is driven in rotation and screwed into the screw hole by means of the rotary drive of the form-fit coupling, preferably in connection with an axial pressure or axial feed, whereby it cuts a mating thread in the screw hole itself.

When screwing in, the clutch release comes into contact with the concrete and holds the form-fit coupling at the specified or adjustable distance from the concrete, so that if the rotary drive continues, the form-fit coupling disengages from the screw head, thereby ending the screwing-in process. The concrete screw protrudes from the concrete by a fixed or adjustable amount and the screw head has a fixed or adjustable distance from the concrete.

The method according to the invention enables concrete screws to be screwed into screw holes in concrete, all screws projecting equally far from the concrete.

One embodiment of the invention provides a tubular clutch release device with an axial stop for the form-fit coupling, which keeps the form-fit coupling at the (minimum) distance from the concrete. The axial stop of the clutch release keeps the form-fit coupling of the rotary drive tool at least at the specified or set distance from the concrete; a greater distance between the form-fit coupling and the concrete is possible.

The tubular clutch release device can have a groove running around an inner circumference on the inside, in which a locking ring is arranged which protrudes inwardly beyond the inner circumference of the clutch release device. The retaining ring forms the axial stop of the clutch release for the form-fit coupling, which ensures the axial distance between the form-fit coupling and the concrete.

One embodiment of the invention provides a socket as a form-fit coupling. Sockets are also known as "socket wrenches". For example, for a hexagon screw head, the socket has a matching hexagon socket. A suitable socket is selected for other screw heads. On one drive side, the socket has, for example, a standardized internal square with a width across flats of, for example, 1 inch or larger or smaller than its rotary drive. The socket enables a rotary drive with, for example, a rotary impact wrench in a simple manner.

The features and combinations of features, designs and configurations of the invention mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or drawn in a figure, are not only in the respectively specified or drawn combination, but also in any other combination Combinations or can be used individually. Embodiments of the invention are possible which do not have all the features of a dependent claim. Individual features of a claim can also be replaced by other disclosed features or combinations of features.

Figur 1

eine perspektivische Explosionsdarstellung einer Betonschraube und eines Drehantriebswerkzeugs;

Figur 2

einen Achsschnitt des Drehantriebswerkzeugs in Eingriff mit der Betonschraube; und

Figur 3

den Achsschnitt aus Figur 2 bei einem Ausrücken des Drehantriebswerkzeugs.

The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing. Show it:

Figure 1

an exploded perspective view of a concrete screw and a rotary drive tool;

Figure 2

an axial section of the rotary drive tool engaged with the concrete screw; and

Figure 3

the axis section Figure 2 upon disengagement of the rotary drive tool.

The rotary drive tool 1 shown in the drawing is used to screw a self-tapping concrete screw 2 into a cylindrical screw hole 3 in concrete 4. In the exemplary embodiment, the concrete screw has a hexagonal screw head 5.

The rotary drive tool 1 has a socket 6 as a form-fit coupling 7 and a tubular sleeve as a clutch release 8. On a drive side, the socket 6 has a standardized internal square 9 with a width across flats of, for example, one inch, with which the socket 6 can be placed on a suitable external square, for example a compressed air or electric impact screwdriver, not shown, and driven in rotation. On an output side opposite the drive side, the socket 6 - matching the hexagon screw head 5 of the concrete screw 2 - has a hexagon socket 10. A suitable, different socket must be selected for a different screw head (not shown). The socket 6 forming the form-fit coupling 7 of the rotary drive tool 1 can be placed on the screw head 5 of the concrete screw 2 or placed axially on the screw head 5 in such a way that it is non-rotatably with the screw head 5 due to a form fit.

As mentioned, the clutch release 8 is a tubular sleeve in which the socket 6 forming the form-locking clutch 7 is received in a rotatable and axially displaceable manner. The clutch release 8 has a circumferential groove on the inside on an inner circumference, into which a locking ring 11 is inserted. Such retaining rings 11 are also referred to as spring rings. The locking ring 11 protrudes approximately half a diameter inward over the inner circumference of the tubular clutch release 8 and forms an axial stop 12 for the socket 6 which forms the form-fit coupling 7 and which has an annular step 13 on its outer circumference for this purpose.

For screwing the self-tapping concrete screw 2 into the screw hole 3 in the concrete 4 according to the invention, the rotary drive tool 1 is used as in FIG Figure 2 to see with its the form-fitting coupling 7 forming socket 6 axially so on The screw head 5 of the concrete screw 2 is placed so that the hexagon socket 10 engages the screw head 5 in a rotationally fixed manner by means of a form fit. The placing of the socket 6 on the screw head 5 can generally also be understood as placing the form-fit coupling 7 on the screw head 5.

The tubular clutch release 8 encloses the socket 6 forming the form-fit coupling 7, the screw head 5 and, to a certain extent, a shaft of the concrete screw 2.

The concrete screw 2 is screwed into the screw hole 3 in the concrete 4 by a rotary drive of the socket 6 forming the form-fit coupling 7 with, for example, the impact wrench (not shown). When screwing in, an axial force is preferably exerted on the form-fit coupling 7 in the direction of the screw hole 3.

The clutch release 8 terminates an axial movement of the socket 6 forming the form-locking clutch 7 in the direction of the concrete 4 when the clutch release 8 is in contact with the concrete 4 and the ring step 13 of the socket 6 is in contact with the internally protruding locking ring 11 in the tubular clutch release 8 arrives, the locking ring 11 forming the axial stop 12 and together with the clutch release 8 a spacer for the socket 6 from the concrete 4. With a further rotary drive of the socket 6, the screw head 5 of the concrete screw 2, which is screwed further into the screw hole 3, emerges from the hexagon socket 10 of the socket 6, i.e. the clutch release 8 disengages the positive coupling 7 of the rotary drive tool 1 from the screw head 5 the concrete screw 2, with which the screwing of the concrete screw 2 into the screw hole 3 in the concrete 4 is completed. The "disengaging" of the form-fit coupling 7 from the screw head 5 is shown Figure 3 . The screw head 5 is at a distance from the concrete 4 which is defined by the clutch release 8. The concrete screw 2 protrudes from the concrete 4 by an amount determined by the clutch release 8.

A plurality of concrete screws 2 are preferably screwed into screw holes 3 in the concrete 4, all of which protrude equally far from the concrete 4. On top of the concrete 4, which can also be referred to as existing concrete, further concrete is poured, which can also be referred to as “top concrete” (not shown). By protruding from the existing concrete 4 concrete screws 2 a shear-proof connection of the Not shown, top concrete with the existing concrete 4 and a connection against lifting of the top concrete from the existing concrete 4 is achieved.

List of reference symbols Method of screwing in a self-tapping concrete screw

1

Rotary drive tool

2

Concrete screw

3

Screw hole

4th

concrete

5

Screw head

6th

Socket

7th

Form-fit coupling

8th

Clutch release

9

Internal square

10

Hexagon socket

11

Circlip

12th

Axial stop

13th

Ring stage

Claims (5)

Method for screwing a self-tapping concrete screw (2), which has a screw head (5), into a threadless screw hole (3) in concrete (4), with a rotary drive tool (1) that can be driven in rotation and that has a form-fit coupling (7) to form a positive fit has a non-rotatable attachment to the screw head (5) and which is attached with its form-locking coupling (7) by form-locking to the screw head (5) and rotatably driven so that the concrete screw (2) is screwed into the screw hole (3), the rotary drive tool (1) has an automatic clutch release (8) which, when the concrete screw (2) is screwed into the screw hole (3), comes into contact with the concrete (4) and keeps the form-fit coupling (7) at a distance from the concrete (4) , so that the form-fit coupling (7) when the concrete screw (2) is screwed further into the screw hole (3) disengages from the screw head (5), so that the concrete screw (2) with ih rem the screw head (5) having the end protrudes from the concrete (4) and the screw head (5) is at a distance from the concrete (4) determined by the clutch release mechanism (8). Method according to Claim 1, characterized in that the clutch release (8) is tubular and has an axial stop (12) for the form-fit coupling (7) which holds the form-fit coupling (7) at a minimum distance from a concrete-side end of the clutch release (8). Method according to Claim 2, characterized in that the clutch release mechanism (8) has a groove running around an inner circumference on the inside, in which a retaining ring (11) protruding inwards beyond the inner circumference of the clutch release mechanism (8) as an axial stop (12) for the form-fit clutch ( 7) is arranged. Method according to one or more of Claims 1 to 3, characterized in that the form-locking coupling (7) has a socket (6). Method according to one or more of the preceding claims, characterized in that the screw head (5) has an external hexagon and the form-fit coupling (7) has a matching internal hexagon (10).

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