GB2556106A

GB2556106A - A device and method for the removal of wall plugs

Info

Publication number: GB2556106A
Application number: GB1619647.9A
Authority: GB
Inventors: Ben Paddick Roger
Original assignee: Np/me Ltd
Current assignee: Np/me Ltd
Priority date: 2016-11-21
Filing date: 2016-11-21
Publication date: 2018-05-23
Also published as: GB201619647D0

Abstract

The tool is a device including a threaded fastener 1 for threadable insertion into a wall plug 21. A shaft 5 is coupled to the threaded fastener and a handle 9 is slidably received on the shaft. Stops 11, 13 are arranged to limit movement of the handle between a first position and a second position on the shaft. The shaft and handle are mutually configured such that relative motion between them is limited to purely linear motion. The handle may include a weight to increase percussive force. A simple, one-handed operation of the device may be achieved by a user using the handle to rotate/drive the threaded fastener into the wall plug and then using the same handle to pull the wall plug from a substrate such as a wall 23.

Description

(54) Title of the Invention: A device and method for the removal of wall plugs Abstract Title: Tool for removing wall plugs (57) The tool is a device including a threaded fastener 1 for threadable insertion into a wall plug 21. A shaft 5 is coupled to the threaded fastener and a handle 9 is slidably received on the shaft. Stops 11, 13 are arranged to limit movement of the handle between a first position and a second position on the shaft. The shaft and handle are mutually configured such that relative motion between them is limited to purely linear motion. The handle may include a weight to increase percussive force. A simple, one-handed operation of the device may be achieved by a user using the handle to rotate/drive the threaded fastener into the wall plug and then using the same handle to pull the wall plug from a substrate such as a wall 23.

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A DEVICE AND METHOD FOR THE REMOVAL OF WALL PLUGS

The present invention relates generally to a device and a method for removing wall plugs from substrates and finds particular, although not exclusive, utility in removal of wall plugs from walls.

Wall plugs (also known as screw anchors, Rawlplugs (RTM) and dowels) are substantially cylindrical bodies of relatively resilient material (e.g. a plastics material, wood or fibre) which may be used to enable attachment of screws or similar fixings into relatively brittle material (e.g. masonry).

In use, a hole is drilled in a substrate, and a wall plug of a size commensurate with the hole is chosen to be inserted into the hole. It is desirable for the wall plug to be a friction fit within the hole (and may therefore require insertion comprising pushing and/or percussion); however, it is also possible for the wall plug to be a loose fit. In either case, wall plugs are often provided with barbs to prevent extraction, but to allow insertion.

A screw can then be driven into the wall plug. Typically, the screw size is also chosen for compatibility with the wall plug. For instance, the wall plug may be provided with an internal bore, and a screw may be chosen that has a shank of a diameter to match that of the internal bore; the screw's thread (around an exterior of the shank) may then cut into the interior surface of the internal bore of the wall plug. The presence of the screw within the wall plug urges an exterior surface of the wall plug outwards, thereby gripping the interior of the hole.

In this way, the screw (and thereby the wall plug) may be inhibited from removal from the substrate by application of a linear force. If the screw is removed, the wall plug may have deformed such that its removal from the substrate becomes increasingly difficult. In any event, removal of a wall plug may be difficult, and may requiring the physical excavation of the material surrounding the wall plug until it is sufficiently freed from its physical grip to enable extraction. The resultant disruption and damage to the surrounding material creates debris and necessitates appreciable repair / making-good works.

In some cases, pliers may be used to grip the wall plug, or a screw inserted therein, so that a user may pull the wall plug from the substrate. Extraction is often unsuccessful in that any inserted screw may either fail to engage correctly within the dowel and/or it may create too great a gripping force within the hole, and skill and experience are therefore required to be successful. In addition, when using pliers, the user is required to simultaneously ensure that the wall plug or screw is the gripped strongly enough, and that a sufficient pulling force is applied to extract the wall plug from the surrounding material.

Alternatively, instead of pliers a claw (for instance, as found on a claw hammer) may be used. Teeth of the claw engage the screw and the screw (and thereby the wall plug) is levered out of the substrate by a pivoting action. In this way, the surface of the material around the wall plug may be damaged, as contact is required to form a fulcrum, and the force applied to the screw to extract the wall plug is not linear (and certainly not axial with the screw / wall plug / hole), but instead is applied around an arc.

These operations and the use of the above-mentioned tools means that extraction may often not be possible in confined spaces.

According to a first aspect of the present invention, there is provided a device for the removal of wall plugs, the device comprising: a threaded fastener for threadable insertion into a wall plug; a shaft coupled to the threaded fastener; a handle slidably received on the shaft; and stops arranged to limit movement of the handle between a first position and a second position on the shaft; the shaft and handle mutually configured such that relative motion between the shaft and handle is limited to purely linear motion.

That is, the handle may be substantially non-rotatable about the longitudinal/sliding axis of the shaft. In this way, simple one-handed operation of the device may be achieved by a user using the handle to rotate/drive the threaded fastener into the wall plug, and then using the same handle to pull the wall plug from the wall. The device may comprise a pull hammer and/or slide hammer.

In use, a user will drive the threaded fastener into a wall plug to be removed by rotating the device about a common axis (e.g. shared between the axis of the threaded fastener and the shaft). The user may apply pressure toward the wall plug by pushing the handle along the shaft toward the threaded fastener, in order to drive the threaded fastener into the wall plug. The user may then pull the handle back along the shaft, gradually accelerating the motion, such that a percussive force is applied to the stop furthest from the threaded fastener. This percussive force is transferred through the shaft to the threaded fastener, and thence to the wall plug, causing the wall plug to be at least partially removed from the hole in the substrate into which it is held. The user may repeat this process (either or both steps) until the wall plug has been removed from the substrate.

The threaded fastener may comprise a relatively coarse thread. For instance, the threaded fastener may comprise a thread having a coarseness value (equal to a ratio of its major diameter to its pitch) of less than 6, in particular less than 5, more particularly less than 4, for example less than 3. In this way, the threaded fastener may be driven securely into a wall plug with only a small amount of turning of the handle, in particular less than a full turn, more particularly less than half a full turn. Therefore a user may not need to adjust grip on the handle during insertion of the threaded fastener.

The threaded fastener may comprise a thread having a major diameter that varies along its axial length. The major diameter of the thread may decrease with increasing distance from the shaft. The thread may taper away from the shaft. In this way, the threaded fastener may be suitable for use over a wide range of wall plug sizes.

Alternatively or additionally, the threaded fastener may be removably coupled to the shaft. In this way, different threaded fasteners (e.g. having various pitches and/or major diameters) may be used to suit different wall plugs.

The thread on the threaded fastener may extend between 20mm and 70mm from the shaft, in particular between 30mm and 60mm, more particularly 40mm and 50mm, for example approximately 45mm.

The threaded fastener may be rotatably coupled to the shaft and/or handle, for instance via a ratchet. In this way, a user may drive the threaded fastener into a wall plug by rotating the device in a first rotational sense and, if more turning is required, may rotate the device in an opposite rotational sense without drawing the threaded fastener out of the wall plug. The ratchet may be of any type known in the art, for instance such as those conventionally used on ratchet screw-drivers and/or spanners / wrenches.

The handle may comprise a weight to increase percussive force. The weight may be at least 40g, in particular at least 50g, more particularly at least 60g, for instance at least 70g or at least 80g.

The shaft may have a non-circular cross-section, for instance square, triangular, hexagonal, or any other shape. Alternatively or additionally, the shaft may comprise a groove and/or a ridge extending substantially along its length, parallel to the longitudinal axis of the shaft.

The handle may fit around the shaft, for instance in close engagement. The handle may have an internal bore shaped to (at least partially) conform to the shape of the shaft cross-section. For instance, the handle may wrap entirely around the shaft; however, other arrangements are envisaged in which the handle lies substantially parallel to the shaft.

The handle may be biased on the shaft, for instance the handle may be biased toward a front end stop. In this way, the tool would feel more positive to a user when being handled, as the handle would be prevented from involuntarily sliding back and forth on the shaft. The biasing may apply a force (for instance with a spring), which may be substantially equal to the weight of the handle, or may be more than the weight of the handle. In this way, the biasing may prevent accidental moving of the handle along the shaft under gravity, but may provide minimal resistance to movement initiated by an operator.

The biasing may be achieved via a spring. For instance, a compression spring may be provided between the handle and an end stop (for instance the rear end stop) which acts to push the handle toward the opposing end stop (e.g. the front end stop). Such a compression spring may be provided around an exterior of the shaft. Such a spring may act to substantially inhibit rotational movement of the handle with respect to the shaft. Alternatively or additionally, an expansion spring may be provided between the handle and an end stop (for instance the front end stop) which acts to pull the handle toward that end stop. Such an expansion spring may be provided around an exterior of the shaft, and may act to substantially inhibit rotation movement of the handle with respect to the shaft. In either case (compression or expansion spring), the spring may be provided within a void within the shaft. For instance, the spring may be provided within the shaft and coupled at a first end to an end stop within the shaft; the opposing end of the spring may be connected to a bar or other projection that extends out through a slot in the shaft and is coupled to the handle. In this way, the bar/projection prevents rotation of the handle with respect to the shaft by being held within the slot. In some embodiments, the bar/projection may extend out through a plurality slots (e.g. a pair of opposing slots, thought other numbers of slots are envisaged) and/or a plurality of such bars/projections may be provided.

Alternatively or additionally, the handle and shaft may be mutually configured such that resistance to motion between the two (e.g. friction) may be substantially equal to the weight of the handle. In a further alternative, a combination of the resistance above and the biasing of the handle on the shaft may combine to be substantially equal to the weight of the handle.

The device may further comprise a cap for covering the threaded fastener when not in use. The cap may have a conventional design such as those used to cover openings on adhesive cartridges. For instance, the cap may be shaped to fit snugly over the threaded faster, and may be provided with a flexible strap that connects the cap to the device, for instance the shaft of the device and/or front end stop; the flexible strap may be thus connected by a loop around a neck of the device. The cap, strap and/or loop may comprise a plastics material.

According to a second aspect of the present invention, there is provided a method of removing a wall plug, the method comprising the steps of: providing a device according to any preceding claim; a user driving the threaded fastener into the wall plug to be removed by pushing the handle towards the threaded fastener and rotating the handle about an axis of the device; a user pulling the wall plug by moving the handle away from the threaded fastener.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 is a side cross-sectional view of a device for removing wall plugs.

Figure 2 is a front end view of the device of Figure 1.

Figure 3 is a rear end view of the device of Figure 1.

Figure 4 is a perspective view of the device of Figure 1 in the process of being inserted into a wall plug located in a substrate.

Figure 5 is a perspective view of the device of Figure 1 being used to remove the wall plug of Figure 4.

The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can he used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term “at least one” may mean only one in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Figure 1 is a side cross-sectional view of a device having at a front end thereof a tapered coarse screw-thread on a threaded fastener 1. The taper may be substantially uniform, for instance, the threaded fastener may have a major axis that varies uniformly along its length (e.g. over the entire length of the thread on the threaded fastener), such that it may be substantially conical. For instance, the threaded fastener may comprise a conical shape having an aperture angle of between 5 and 25 degrees, in particular between 10 and 20 degrees, more particularly approximately 15 degrees. The conical shape may extend over between 20mm and 70mm from the shaft, in particular between 30mm and 60mm, more particularly 40mm and 50mm, for example approximately 45mm.

In alternative embodiments, the thread on the threaded fastener may be substantially helical (that is, untapered). However, notwithstanding the above, the thread on the threaded fastener may include a relatively small portion (e.g. up to 10mm, in particular up to 5mm, more particularly up to 2mm) that is tapered on the end of the substantially helical portion.

The threaded fastener may be constructed from steel; however, other common materials are also envisaged.

The threaded fastener 1 is shown as being threadably received within a socket 3; however, other methods of connection (e.g. clamp, collet, etc.) are also envisaged. The socket 3 includes a relatively fine female socket thread for engaging with a further corresponding fine male thread on the threaded fastener 1.

The socket 3 is fixed within a front end of a square aluminium tubular metal shaft 5. For instance, the shaft 5 may be approximately 15mm square aluminium section with an approximately 2mm wall thickness. However, other widths, thicknesses and materials are also envisaged. The shaft 5 may be hollow with a void 7 therein.

A handle 9 is slidably received on the shaft 5. The handle 9 may also be constructed of square section aluminium tube. The square section dimension of the handle 9 may be marginally larger than that of the shaft 5 so that the handle 9 is free to slide along the tool shaft 5. The handle 9 may be shaped for a close fit on the shaft 5 to prevent movement in any direction/sense other than linear along the axis of the shaft 5.

The handle may be approximately 20mm square aluminium section with an approximately 2mm wall thickness. However, other widths, thicknesses and materials are also envisaged.

The shaft 5 is proportionally longer than the handle 9 to give sufficient length to achieve the reciprocating sliding action of the handle 9 between either end of the shaft 5, to create the pulling force for extraction of the wall plug. For instance, the tool shaft may have a length of approximately 180mm, and the tool handle may have a length of approximately 140mm. However, other lengths are also envisaged.

The handle 9 may have a foam hand grip to assist operation of the tool and to aid operator comfort. However, other forms of hand grip other than foam are also envisaged, such as moulded plastics material. In particular, the grip may be integrally formed with the handle 9, for instance by moulding. The grip may be provided with a textured surface as is well known in the art.

To prevent sliding of the handle 9 off the shaft 5, a front end stop 11 is provided at a front end of the shaft 5. The front end stop 11 may have a through hole, through which is passed the threaded fastener 1 when connected to the socket 3, such that the front end stop 11 is held in place on the shaft 5 by the threaded fastener 1.

Similarly, a rear end stop 13 may be attached by a screw fastener 15 into a rear socket 17 that is securely fixed into a rear end of the shaft 5. It is to be appreciated that other methods of affixing the end stops, such as welding, gluing, etc. are also envisaged.

The end stops are shown as being round; however, these may be of any shape, the end stops may be removable. In particular, the void 7 within the shaft 5 may be accessible for storage of components therein, for instance by removal of the rear end stop 13.

Figure 2 is a front end view of the device of Figure 1 showing the threaded fastener 1, the front end stop 11 and the handle 9.

Figure 3 is a rear end view of the device of Figure 1 showing the rear end stop 13, the bolt/screw fastener 15 (shown having a hex socket, but other screw drives are possible), and the handle 9.

Figure 4 is a perspective view of the device of Figure 1 in the process of being inserted into a wall plug 21 located in a substrate 23. A user may drive the threaded fastener 1 into the wall plug 21 by rotating the handle 9 in the rotational sense indicated by the arrow. Due to the co-operating square cross-sections of the handle 9 and shaft 9, this enables the threaded fastener 1 to rotate, allowing its thread to bite into the wall plug 21.

Optionally, the handle 9 may be slid up the shaft 5 against the front end stop 11 such that the user may push the threaded fastener 1 into the wall plug 21.

Figure 5 is shows removal of the wall plug 21 from the hole 25 in the substrate

23, after the insertion of the threaded fastener 1 shown in Figure 4. Sliding the handle 9 rearwardly along the shaft 5 (i.e. away from the front end stop 11), causes the handle 9 to hit the rear end stop 13. The impact force of the collision of the handle 9 with the rear end stop 13 is transferred through the device to the threaded fastener 1 and thence to the wall plug 21, allowing extraction of the wall plug 21 from the hole 25.

Claims

1. A device for the removal of wall plugs, the device comprising: a threaded fastener for threadable insertion into a wall plug;

a shaft coupled to the threaded fastener; a handle slidably received on the shaft; and stops arranged to limit movement of the handle between a first position and a second position on the shaft;

the shaft and handle mutually configured such that relative motion between the shaft and handle is limited to purely linear motion.

2. The device of claim 1, wherein the threaded fastener comprises a thread having a ratio of its major diameter to its pitch of less than 6.

3. The device of claim 1 or claim 2, wherein the threaded fastener comprises a thread having a major diameter than varies along its axial length.

4. The device of any preceding claim, wherein the threaded fastener is rcrmwalily coupled to the shaft.

5. The device of any preceding claim, wherein the handle comprises a weight to increase percussive force.

6. The device of any preceding claim, wherein the shaft has a non-circular crosssection.

7. A method of removing a wall plug, the method comprising the steps of: providing a device according to any preceding claim;

a user driving the threaded fastener into the wall plug to be removed by pushing the handle towards the threaded fastener and rotating the handle about an axis of the device;

a user pulling the wall plug by moving the handle away from the threaded fastener.

Intellectual

Property

Office

Application No: Claims searched:

GB1619647.9

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