Method for screwing a self-tapping concrete screw

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 bearing (8), which, upon contact with a retaining ring (11) inside the clutch release bearing (8), disengages the socket (6) from a screw head (5) of the concrete screw (2) and thereby terminates the screwing.

Description

[0001] The invention relates to a use of a rotary drive tool 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 screwed - normally with the aid of a pneumatic or electric impact wrench - into a drilled, cylindrical screw hole in concrete, for example, whereby the concrete screws cut a counter thread in the screw hole themselves.

[0002] To strengthen load-bearing concrete structures, such as the roadway of a bridge, it is common practice to add an additional layer of concrete to the structure. This concrete layer typically has reinforcement and is designed to absorb increased bending loads, increasing the load-bearing capacity of the structure. To ensure force transfer, particularly 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 rather in such a way that the screw head protrudes significantly from the structure. The subsequently applied concrete layer can then encompass the screw head, allowing the concrete screw to transfer forces between the structure and the new concrete layer.To achieve a specific distance between the screw head and the structure, it is conceivable that the holes for the concrete screws are drilled, for example, using a stop on the drill bit, only to the depth required for the concrete screws to touch the bottom of the drilled hole when the desired position is reached. However, this carries the risk that the concrete screws will be subjected to such a strong torque upon reaching the bottom of the drilled hole that either the concrete screw or the internal thread in the concrete created by the concrete screw will be damaged. A generic rotary drive tool for screwing in a concrete screw is known from WO 2016 / 139095 A2. This shows a use with the features of the preamble of claim 1.

[0003] The object of the invention is to propose a use of an alternative rotary drive tool for screwing a self-tapping concrete screw into concrete with a fixed projection of the screw from the concrete and a fixed distance of a screw head from the concrete.

[0004] This object is achieved according to the invention by the features of claim 1. The inventive use utilizes a rotary drive tool with a positive-lock coupling and a clutch release mechanism. The positive-lock coupling has, for example, a hexagon socket, such as a pipe wrench or a socket, matching a hexagon screw head of the concrete screw. Other positive-lock couplings, matching a different screw head, are possible. The positive-lock coupling can be attached to the screw head of the concrete screw in a rotationally fixed manner by means of a positive lock, so that the screw can be driven in rotation by the rotational drive of the positive-lock coupling.

[0005] The clutch release mechanism ensures a (minimum) distance between the positive-locking clutch and the concrete, including the screw hole into which the concrete screw is screwed. This distance can be fixed or adjustable.

[0006] To screw the concrete screw into the screw hole in the concrete, the form-lock 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-lock. By rotating the form-lock coupling, preferably in conjunction with axial pressure or axial feed, the screw is driven to rotate and screwed into the screw hole, cutting its own counter-thread in the screw hole.

[0007] During screwing, the clutch release engages the concrete and holds the positive-lock coupling at a specified or adjustable distance from the concrete, so that upon continued rotation, the positive-lock coupling disengages from the screw head, thus completing the screwing process. The concrete screw protrudes from the concrete by a specified or adjustable amount, and the screw head is at a specified or adjustable distance from the concrete.

[0008] The use according to the invention enables concrete screws to be screwed into screw holes in concrete, with all screws protruding the same distance from the concrete.

[0009] The invention provides a tubular clutch releaser with an axial stop for the positive-locking clutch, which keeps the positive-locking clutch at the (minimum) distance from the concrete. The axial stop of the clutch releaser keeps the positive-locking clutch of the rotary drive tool at least at the specified or set distance from the concrete; a greater distance of the positive-locking clutch from the concrete is possible.

[0010] The tubular clutch release mechanism may have a groove on its inner circumference, in which a retaining ring is arranged, which protrudes inward beyond the inner circumference of the clutch release mechanism. The retaining ring forms the axial stop of the clutch release mechanism for the positive-locking clutch, which ensures the axial distance of the positive-locking clutch from the concrete.

[0011] One embodiment of the invention provides a socket as a form-lock coupling. Sockets are also referred to as "socket wrenches." For example, for a hexagon screw head, the socket has a matching hexagon socket. For other screw heads, a matching socket is selected. On one drive side, the socket has, for example, a standardized square drive with a wrench size of, for example, 1 inch or larger or even smaller than its rotary drive. The socket enables a simple rotary drive with, for example, an impact wrench.

[0012] The features and combinations of features, embodiments, and refinements 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, can be used not only in the respective combination specified or drawn, but also in any other combinations or individually. Embodiments of the invention are possible that 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.

[0013] The invention is explained in more detail below using an exemplary embodiment illustrated in the drawing. In the drawings: Figure 1 is an exploded perspective view of a concrete screw and a rotary drive tool; Figure 2 is an axial section of the rotary drive tool in engagement with the concrete screw; and Figure 3 is the axial section of Figure 2 when the rotary drive tool is disengaged.

[0014] 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 hexagon screw head 5.

[0015] The rotary drive tool 1 has a socket 6 as a positive-lock coupling 7 and a tubular sleeve as a clutch release 8. On one drive side, the socket 6 has a standardized internal square 9 with a wrench size of, for example, one inch, with which the socket 6 can be placed on a suitable external square, for example, of a pneumatic or electric impact wrench (not shown), and driven in rotation. On an output side opposite the drive side, the socket 6 has a hexagon socket 10 - matching the hexagon screw head 5 of the concrete screw 2. For a different screw head, a suitable, different socket must be selected (not shown).The socket 6 forming the form-lock 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 rotationally fixed to the screw head 5 by form-lock.

[0016] As mentioned, the clutch releaser 8 is a tubular sleeve in which the socket 6 forming the positive-locking clutch 7 is rotatably and axially displaceably received. The clutch releaser 8 has a circumferential groove on its inner circumference, into which a retaining ring 11 is inserted. Such retaining rings 11 are also referred to as spring rings. The retaining ring 11 projects inwardly by approximately half a diameter beyond the inner circumference of the tubular clutch releaser 8 and forms an axial stop 12 for the socket 6 forming the positive-locking clutch 7, which socket 6 has an annular step 13 on its outer circumference for this purpose.

[0017] 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 shown in Figure 2 As can be seen, with its socket 6 forming the form-lock coupling 7, it is placed axially onto the screw head 5 of the concrete screw 2 in such a way that the hexagon socket 10 engages the screw head 5 in a rotationally fixed manner by means of a form-locking connection. Placing the socket 6 onto the screw head 5 can generally also be understood as attaching the form-lock coupling 7 to the screw head 5.

[0018] The tubular clutch releaser 8 encloses the socket 6 forming the positive coupling 7, the screw head 5 and a portion of a shaft of the concrete screw 2.

[0019] By rotating the socket 6 forming the form-lock coupling 7, for example using the impact wrench (not shown), the concrete screw 2 is screwed into the screw hole 3 in the concrete 4. During screwing, an axial force is preferably exerted on the form-lock coupling 7 in the direction of the screw hole 3.

[0020] The clutch releaser 8 ends an axial movement of the socket 6 forming the form-fitting clutch 7 in the direction of the concrete 4 when the clutch releaser 8 comes into contact with the concrete 4 and the annular step 13 of the socket 6 comes into contact with the inwardly projecting retaining ring 11 in the tubular clutch releaser 8, wherein the retaining ring 11 forms the axial stop 12 and, together with the clutch releaser 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 of the concrete screw 2, thus completing the screwing of the concrete screw 2 into the screw hole 3 in the concrete 4. The "disengagement" of the positive coupling 7 from the screw head 5 shows Figure 3 The screw head 5 is spaced from the concrete 4 by a distance determined by the clutch release 8. The concrete screw 2 protrudes from the concrete 4 by a distance determined by the clutch release 8.

[0021] Preferably, several concrete screws 2 are screwed into screw holes 3 in the concrete 4, all of which protrude the same distance from the concrete 4. Additional concrete, also referred to as "topping concrete" (not shown), is poured onto the concrete 4, which can also be referred to as the existing concrete 4. The concrete screws 2 protruding from the existing concrete 4 create a shear-resistant connection between the topping concrete (not shown) and the existing concrete 4, preventing the topping concrete from lifting off the existing concrete 4. List of reference symbols

[0022] 1Rotary drive tool 2Concrete screw 3Screw hole 4Concrete 5Screw head 6Socket 7Form-lock coupling 8Clutch releaser 9Square socket 10Allen key 11Retaining ring 12Axial stop 13Ring step

Claims

1. Use of a rotatably drivable rotary drive tool (1) for screwing a self-tapping concrete screw (2), which has a screw head (5), into a threadless screw hole (3) in concrete (4), wherein the rotary drive tool (1) has a form-fit coupling (7) for non-rotatably attaching to the screw head (5) by form-fit coupling and which is non-rotatably attached to the screw head (5) by form-fit coupling (7) and is driven in rotation so that the concrete screw (2) is screwed into the screw hole (3), wherein the rotary drive tool (1) has an automatic coupling release (8) which, when the concrete screw (2) is screwed into the screw hole (3), comes into contact with the concrete (4) and holds the form-fit coupling (7) at a distance from the concrete (4), so that the form-fit coupling (7) is disengaged from the screw head (5) when the concrete screw (2) is screwed further into the screw hole (3), so that the concrete screw (2) protrudes from the concrete (4) with its end having the screw head (5) and the screw head (5) has a distance from the concrete (4) determined by the coupling release (8), characterized in that the coupling 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 coupling release (8).

2. Use according to claim 1, characterized in that the coupling release (8) has a groove running around an inner circumference, in which groove a retaining ring (11) projecting inwards beyond the inner circumference of the coupling release (8) is arranged as an axial stop (12) for the form-fit coupling (7).

3. Use according to claim 1 or 2, characterized in that the form-fit coupling (7) has a socket (6).

4. Use according to one or more of the preceding claims, characterized in that the screw head (5) has an external hexagon socket and the form-fit coupling (7) has a matching internal hexagon socket (10).

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