Wall fixing

Abstract

A drilling and fixing device for hollow walls or panels comprising a front plate or stop 10 for resting on the panel surrounding and allowing access to the hole in which the device fits, a mounting body 20 forward of the plate and a pivoting arm 40 mounted on the body. The pivoting arm has a cutting surface on the forward part of the arm and is moveable from a rear position in the mounting body in which its axial direction is fixed to allow a hole to be drilled in the panel and a forward position in the mounting body in which position it can pivot to lie approximately horizontal to the panel when in use. The movement into the forward position and the pivoting of the arm can be brought about by the insertion of a screw through the front plate. The screw may engage the mounting body to pull it back, with the arm until the device is secure in the hole. The device may have two arms where the blades on the forward ends overlap when in the rear position to cooperate in the drilling process.

Description

The present invention relates to wall fixings, in particular such fixings as have an integrated drilling feature for installation into a plasterboard wall or other panel such as a board or sheet material. Most usually this would be a plasterboard wall with a wet plaster finish. Fixings for plasterboard generally have a part that is pushed through the hole made in the board to apply the fixing, and which is then spread laterally and retracted to bear against the rear (blind) face of the panel. Such a part may simply be a pair of splayed arms integral with the fixing. More sophisticated versions may have separate moving parts, e.g. splayed arms mounted on a screw thread, or hinged, as in US 2014 / 271031 (Agri et al.), which are brought to bear against the rear face of the panel. A similar device is disclosed in GB 2581539A by C. Goodenough. A further version of the latter type is revealed in EP 1861627 Al by Cobra Fixations Cie. (Cobra Anchors Co). This fastening has the further quality of incorporating a cutting or self-drilling feature. A toggle or anchor member having a cutting tip is mounted in a generally cylindrical framework or body; the toggle is rigidly held when in its rear location in the body, so that it can function to drill the hole in the panel or hollow wall. Once this is done, a screw is inserted, which pushes the toggle forward and releases it to tilt until it is parallel to the panel. The screw then engages a bore in the toggle, and further turning pulls the toggle back until it engages the panel, holding the fixing firmly. According to the present invention there is provided a fixing device for hollow walls or panels, comprising: - a front plate or stop for resting on the panel surrounding the hole in which the fixing device is to sit, the front plate or stop allowing access to the hole; - a mounting body arranged forwardly of the front plate, and - a pivoting arm mounted in the mounting body; wherein the pivoting arm has a forward cutting point or edge, and is moveable from a rear position in the mounting body, in which its axial direction is fixed and in which the arm can be turned about its axis in order to drill a hole in the panel, and a forward position in the mounting body, in which position it can pivot so as to lie approximately parallel to the panel when in use; and wherein the movement into the forward position, and the pivoting of the arm, can be brought about by insertion of a screw though the hole, the screw then preferably engaging the mounting body to pull it back, with the arm, until the device is secure in the hole in the panel. In fact there are preferably two arms, either side of the axis, whose forward ends, when in the rear position, generally overlap as seen in a plane containing the axis of the device, so as to co-operate in the drilling procedure. An advantage of having two arms is greater stability of the clamping procedure, since the arms abut either side of the hole, and it does not matter which arm is uppermost. The arm or arms pivot on a bearing protrusion, or a pair of such, which can slide in axial grooves in the mounting body. In the vicinity of the bearing on the arm there can be a bearing face extending generally perpendicularly to the arm, which is acted on by the screw as it is inserted so as first to slide the arm and then to pivot it outwardly. The arms can have flats over most of their length, located outwardly on the arms with respect to the axis, so that they come to rest against the panel when the arms are retracted by the screw against the rear face of the panel. The sliding body can be in two parts, forward and rear, for ease of assembly, the arm or arms being held captive between the two parts. "Forward" and "rear" here mean in the direction of insertion into the panel. The front plate or stop is wider than the outline of the body with the arms, so that it prevents the assembly from disappearing into the hole when drilling is complete. It is slidably connected to the body, e.g. by brackets or retaining arms, on which the body slides, so that the body, with the arms now in the splayed configuration, can be retracted to press against the back of the panel. This configuration can then also accommodate walls or panels of different thicknesses . The mounting body preferably has a central threaded bore with which the screw or bolt engages for retracting the body to tighten it against the panel. It will be appreciated that having the arm or arms separately carried in the mounting body allows the latter to retain its axially aligned orientation, so that the user will easily be able to insert the screw; this is in contrast to the Cobra fitting, where the anchor must first rotate until the hole is opposite the screw. It is also impossible for there to be two conical drill-shaped anchors since they would interfere. For a better understanding of the invention, embodiments will now be described with reference to the attached drawings, in which: Figure 1 is a view of a fixing device in accordance with the invention, before use; Figure 2 is an axial cross-section corresponding to Figure 1; Figure 3 is a view of the device in situ, during the fixing process; Figure 4 shows an exploded view corresponding to Figure 3; Figure 4A is a sectional view through the body; Figure 5 shows the sequence of steps in the wall fixing process; and Figure 6 shows a screwdriver being used for the initial drilling procedure. Figure 1 shows a fixing device 1 embodying the invention. The device consists of a front plate 10, a two-part body 20 and two wings or arms 40, upper and lower, pivotably mounted in the body. The terms "upper" and "lower" are used for convenience, there being no particular significance to the orientation of the device, except that in use one of the arms should be uppermost. In the preparatory or collapsed state shown, the forward ends 42 of the arms, which are in the shape of pointed blades, lie on, or just to the side of, the axis of the device and overlap. The bulk of the length of each arm exhibits an outer circumferential or lateral surface 44, which will ultimately rest against the inner face of the wall or panel. Figure 2 shows a vertical cross-sectional view through the device. The two arms 40 can be seen, which are arranged so that their pointed ends 42 overlap. To this end their pointed ends 42 are slightly offset from the axis. For manufacturing convenience the two arms can in fact be identical. The section also shows how the combination of the front ends of the arms imitates a paddle drill bit, for the drilling operation. The forward edge 43 of the ends also acts as a cutter. The section also illustrates the rear (user-end) part or cap 20a of the mounting body. Figure 3 illustrates the device with the arms 40 splayed, when in situ in a panel. The panel itself, which will have had a hole drilled in it by the wings 40 when in the folded state, is not shown. The arms have been moved from their compact configuration to the expanded state shown by insertion of a machine screw 80, as will be described later. Figure 4 shows an exploded view corresponding to Figure 3. Here it can be seen how the body 20 is in two parts, the rear part or cap 20a and the more or less cylindrical front part 20b. These are clipped together by forward-facing arms or brackets 22 on the cap 20a, engaging in corresponding recesses in the forward part 20b. Clearly the fastening could be done in other ways. The drawing also shows the axis 60 of the device, which in use is of course perpendicular to the panel. The assembled body is attached to the front plate 10 by two retaining arms or brackets 12 on the latter, affording some leeway for axial sliding to allow for tightening of the fixing device, and preferably also so as to accommodate different thicknesses of panel. The body holds captive the two arms 40, which each have at their base (rearward when in the folded configuration of Figure 1, inward when splayed) a pair of bearing pins 46 held in a pair of axially oriented grooves 26 on the inside of the forward body part 20b. The wings / arms also have a pair of protrusions 48 forward of the pins 46, each bearing a rearfacing catch 48a. The catches also slide in dedicated locking apertures 28 (see Figure 4A) , which here are slightly narrower grooves forward of the pivot grooves 26, but are released, allowing the arms to pivot, once they have travelled forwards past a certain point. The cap 20a has a central (axial) aperture 24, aligning with a similar aperture 14 in the front plate 10 so that the combined aperture receives a crosshead screwdriver bit for driving the drilling operation, to be described. The aperture 24 in the body is also aligned with a central aperture 29 in the body 20b, which is threaded to receive a machine screw 80 to complete the fixing operation, as will also be described. Each arm 40 has a protrusion or heel 50 at its base, adjacent to the pins 46, and facing inward, when in the folded state, so as to obscure the passage through the device; this can be best seen in Figure 2. Figure 5 shows the successive stages of operation when fixing the device in a panel wall. First, as in Figure 5(a),the device is in its compact or folded state, and is applied to the desired spot on the panel. The pointed and overlapping ends of the arms start to penetrate the panel as pressure and rotation are applied by, typically, a screwdriver. The fixing device is held in its folded state by pressure against the panel urging the device rearwardly, so that the protrusions 48 remain held in the grooves, though additional closure mechanisms may also be present. By applying pressure and rotation to the screwdriver the drilling element will bore a hole in the panel or board material. The crosshead screwdriver engages with grooves or indentations in the wall of the combined apertures 14 and 24, which can best be seen in Figures 1 and 4. After the device has penetrated the panel (Figure 5(b)), it is pushed further in until the front plate 10 is retained by its outer lip, as shown in Figure 5(b). At this point the screwdriver is removed and the screw 80 inserted. The screw abuts against the heels 50 of the arms and pushes the body 20 further in (Figure 5(c)), so that the bases of the arms are clear of the panel. The pivot pins 46 also slide along the grooves 26; after a travel of, say, 4mm relative to the body the catches 48a on the protrusions 48 are released from the locking grooves 28, and the arms are free to pivot outwards. This they do because of the moment applied via the heels 50 about the pivot pins, and the arms splay outwards to their configuration as shown in Figures 3 and 4. Once the screw passes the bases of the arms they cannot turn back but are locked in their splayed position. The screw, which engages in a thread in the body 20b after it has passed beyond the bases of the arms, is then turned, pulling the device back towards the user until the flat faces 44 of the arms rest against the inner surface of the panel, as shown in figure 5(d). Figure 5(e) shows the same end result but for a thicker (e.g. 16 mm) panel, the difference being taken up by the body sliding with respect to the front plate 10. Figure 6 shows the screwdriver 100 applied to the device to drive the drilling operation. The same or a different screwdriver could be used to insert the screw when the fixture is in place. Notable features of the system include the following. The device is a self-drilling wall fixing that incorporates a drilling feature and can be installed with a screwdriver only. Drilling is typically achieved with a combination of two arms working together. During drilling the arms are locked in position. Each arm forms half of the drill and they work in combination. Following drilling, the arms are moved by the insertion of a screw, forcing them to translate in the primary product axis (in the direction the screw is inserted). During this translation the arms are guided by the locking features until these are disengaged. Once the locking features are disengaged the continued insertion of the screw forces the arms to rotate using a cam. Once the arms are fully rotated to approximately 90 degrees then the screw passes between the arms and prevents them from closing. The axis of rotation is not fixed in the body, but slides in the direction of insertion. For the self-drilling feature the arms at least are made of a hard material suitable for drilling a variety of substrates. The arms feature larcje flat surfaces that bear against the rear of the panel material, resisting pull-out. The product advantageously has a largely symmetrical construction so can be orientated vertically or at 180° from this position and have identical performance. However, the plate preferably has clear installation orientation markings to ensure that the fixing is installed in an optimal orientation. The device can be constructed using die-cast zinc, injection-moulded plastic or another material, or more than one of these . 5 A typical device is typically capable of automatic adjustment for wall thickness, say from 9mm to 16mm. Typical dimensions are 42mm (say 30-60mm) in length, 16mm (say 10-20mm) diameter of body with arms, 20mm (say 12-25mm) diameter of plate. Insertion of the screw disengages the drilling lock function 10 and rotates the arms to the open position. Once the arms are in the extended position they are locked in place by the screw which prevents their closure.

Claims

4Claims1. A drilling and fixing device for hollow walls or panels, comprising:a front plate or stop (10) for resting on the panel surrounding the hole in which the fixing device is to sit, the front plate or stop allowing access to the hole;a mounting body (20) arranged forwardly of and slidably connected to the front plate, defining a drilling axis (60), anda pivoting arm (40) mounted in the mounting body;wherein the pivoting arm has a forward cutting point or edge (42), and is moveable from a rear position in the mounting body, in which its axial direction is fixed and in which the arm can be turned about the axis of the body in order to drill a hole in the panel, and a forward position in the mounting body, in which position it can pivot so as to lie approximately parallel to the panel when in use;and wherein the movement into the forward position, and the pivoting of the arm (40), can be brought about by insertion of a screw (80) though the front plate, the screw then engaging the mounting body (20) to pull it back, with the arm, until the device is secure in the hole in the panel.

2. A device according to claim 1, in which there are two arms (40), either side of the axis, whose forward ends, when the body is in the rear position, generally overlap as seen in a plane containing the axis of the device, so as to co-operate in the drilling procedure.

3. A device according to claim 1 or 2, in which the or each arm has a pair of bearing protrusions (46) which slide in axial grooves (26) in the mounting body between the rear and forward positions, and about which the arm can pivot07 11 24when in the forward position.

4. A device according to any preceding claim, in which each arm has a bearing face or heel (50) extending generally perpendicularly to the arm and inwardly of the axis when the arm is in the rear, unextended, position, the heel being acted on by the screw (80) as it is inserted so as first to slide the arm and then to pivot it outwardly.

5. A device according to any preceding claim, in which the arms have flats (44) over most of their length, located outwardly on the arms with respect to the drilling axis, so that they come to rest against the panel when the arms are retracted by the screw against the rear face of the panel.

6. A device according to any preceding claim, in which the mounting body is in two parts, forward (20b) and rear (20a), the arm or arms being held captive between the two parts.

7. A device according to any preceding claim, in which the front plate or stop is slidably connected to the body by retaining arms (12), on which the body slides, so that the body, with the arms in the splayed configuration, can be retracted to press against the back of the panel.

8. A device according to any preceding claim, in which the mounting body (20) has a central threaded bore (29) with which the screw or bolt engages for retracting the body to tighten it against the panel.

9. A kit comprising a drilling and fixing device as in any preceding claim and a screw (80) adapted to engage with the mounting body.

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