Technical Field of the Invention

The invention relates to tools, specifically tools suitable for extracting fasteners from a panel, in particular but not exclusively tools for extracting a screw from a panel.

Background to the Invention

Fasteners such as screws or bolts are typically used to attach objects together. The objects may include panels, sheets, planks or strips of material such as metal, wood or plastic; hereinafter referred to as panels. The typical fastener is threaded such that it can be driven (screwed) into the material by a tool such as a screwdriver. A screw or bolt head typically comprise a slot for a flathead or crosshead screwdriver to engage whilst the user applies compression and torsion (typically clockwise) on the screwdriver. As torsion is applied to the fastener, the threads engage either the material itself or formations within a bespoke hole or nut to force the fastener into the hole and embed it into the panel.

Generally, it is desirable to extract (unscrew) the fastener from the panel to detach the objects from each other. This is typically achieved using a screwdriver and applying compression and torsion (typically anti-clockwise). Compression is still required during extraction so that the screwdriver is able to engage the slot in the fastener and doesn’t slip out.

It is fairly common for the slot in the fastener to become stripped i.e. damaged. This can occur if the fastener becomes stubborn due to age or environmental corrosion. Corrosion may weaken the walls of the slot such that they disintegrate as torsion is applied. In addition, the fastener may become stripped if the user attempts to extract it using the incorrect screwdriver size and/or shape and/or misaligns the screwdriver tip in the slot thereby damaging the walls of the slot. Furthermore, the fastener may be stripped if the user applies insufficient compression during extraction such that the tip of the screwdriver slips out of the slot and damages the slot walls. Consequently, the stripped fastener remains embedded in the panel and is significantly more difficult to extract.

The present invention seeks to mitigate one or more of these issues.

Summary of the Invention

According to a first aspect, the invention provides a tool for extracting a screw from a panel, the tool comprising: a clamp comprising adjustable opposable jaws; wherein a screw engagement means is pivotably mounted to the first jaw; such that, in use, the screw engagement means can be independently rotated whilst clamped against the screw to extract it from the panel. Pivotably mounting a screw engagement means to the first jaw enables the user to apply torsion to the screw, typically using an external tool, whilst the clamp compresses the screw engagement means into the screw. Using a clamp to apply compression reduces the risk of stripping the screw because compression is increased and the screw engagement means is held in alignment with the screw.

Generally, a clamp is a fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward force/pressure by the jaws. The clamp may be any of those known in the art such as a bar clamp, pipe clamp, F clamp, G clamp (C clamp) or a spring clamp or even a vise. The clamp comprises adjustable and opposable jaws. The jaws may be opened and closed by the user, the distance between the jaws being adjustable using a mechanism. Closing the jaws against the front and rear surfaces of the panel and/or the fastener provides an inward force thereby gripping the panel and securely holding the clamp and screw engagement means in position. In some embodiments the mechanism comprises one or both of the jaws being threaded and pivotably mounted to a clamp body. In other embodiments the jaws may comprise elongate arms connected at a pivot and formed into handles at the opposing end or any other clamp mechanism known in the art. Typically once the distance between the jaws is set, the mechanism securely holds the jaws at their positions to prevent the jaws from separating. A screw engagement means is typically any form of contacting, gripping, engaging, interlocking, or meshing the screw engagement means with the fastener such that torsion applied to the screw engagement means is transferred to the fastener. In some embodiments the screw engagement means is a screwdriver tip which is shaped to fit the driving surfaces e.g. slots, grooves, recesses on the corresponding screw head. The tip may be a flat head, cross head, Torx®, Pozidriv, Tri-Wing, Hex or any other known type of screwdriver tip. In other embodiments, the screw engagement means is a broken bolt and/or screw extractor designed to engage a stripped fastener and extract it using compression and torsion. The extractor may comprise a grip to engage the head of the fastener. In some embodiments, the grip may comprise a conically shaped end portion, which may be reverse threaded or comprises a reverse flute and/or axial grooves, for engaging the stripped slot. In other embodiments the extractor may comprise an interior bore that engages the fastener head, the interior surface of the bore may comprise grooves for gripping the surface of the fastener head.

The screw engagement means is pivotably mounted onto a first of the adjustable opposable jaws. Generally the screw engagement means is attached to the first jaw and is capable of being independently rotated or turned about the point of direct or indirect attachment or pivot whilst clamped against the fastener to extract it from the panel. Independent rotation is typically actioned by the user gripping the screw engagement means either by hand or an external tool such as a spanner, wrench or pliers and applying torsion. The pivot axis (i.e. the axis about which the screw engagement means rotates) is typically in alignment with, substantially parallel and/or coaxial with the fastener’s axis. The pivot axis may be substantially parallel to the direction the jaws are arranged to move towards and away from each other in the device. The pivot axis may be substantially perpendicular to the face of the first and/or second jaw. In some embodiments the clamp comprises a threaded jaw and the pivot axis is substantially parallel to the axis of the threaded jaw.

Generally, the clamp compresses the screw engagement means against the screw for example a cross head screwdriver tip into the cross head slot of an embedded screw and holds them in alignment. The user rotates the screwdriver tip to drive the embedded screw (typically anti-clockwise) to extract it from the panel. Preferably, a clamp plate is pivotably mounted to the second jaw. Typically the clamp plate engages the rear surface of the panel and can be freely rotated relative to the second jaw and clamp body. This helps to position the clamp around the screw and panel.

Preferably, the clamp plate comprises formations arranged to mate with the rear surface of the panel. The formations are arranged to mate or interlock with corresponding formations in the rear surface of the panel. The formations may comprise inwardly or outwardly curving surfaces or protrusions on the clamp plate. The formations may mirror corresponding curving surfaces on the rear surface of the panel adjacent to the embedded screw. The formations may mirror the surface profile of the rear or any other surface of the panel. Mating the formations with corresponding formations on the rear surface of the panel helps to align the screw engagement means with the screw thereby reducing the risk of stripping the screw. In addition, once mated, the mated formations reduce rotation of the clamp plate whilst the jaws are being adjusted (particularly for pivotably mounted jaws) allowing increased compression of the screw engagement means against the screw and reducing the risk of stripping the screw.

Preferably, the clamp plate is removable from the second jaw. Having a removable clamp plate enables the user to detach the clamp plate and attach an alternative clamp plate with different formations better suited to mate with the rear surface of the panel.

Preferably, the screw engagement means comprises a screwdriver tip shaped to fit the driving surfaces on the corresponding screw head. The screwdriver tip is compressed into the slot in the head of the screw by the clamp in alignment with the fastener and preventing the tip from slipping out of the slot and stripping the fastener whilst torsion is applied. Typically the screw head is protruding from the front surface of the panel.

Preferably, the screw engagement means comprises a screw extractor or bolt head grip. The screw extractor is compressed into the (typically stripped) slot of the screw head by the clamp to hold the screw extractor in alignment with the fastener and preventing the screw extractor from slipping out of the slot whilst torsion is applied. Similarly, the bolt head grip is securely held over the head of the fastener. Using a screw extractor or bolt head grip is advantageous for extracting stripped fasteners.

Preferably, the screw engagement means comprises a hex nut. The hex nut can be engaged by a spanner, wrench or pliers to provide grip whilst the user applies torsion during extraction. This allows increased torsion during extraction which may be useful for particularly stubborn embedded fasteners.

Preferably, the screw engagement means comprises a handle. The handle is securely attached to the screw engagement means and allows the user to apply increased torsion without the use of an external tool such as a spanner. In some embodiments, the handle protrudes radially outwards from the screw engagement means.

Preferably, the clamp comprises a G clamp. A G clamp typically comprises a fixed jaw and a threaded jaw in a C or G shaped body. A G clamp is advantageous because it provides a powerful clamping force, large maximum opening and a deep throat depth (depth of reach) as well as being sturdy.

Preferably, the pivot axis is substantially parallel to the direction the jaws are arranged to move towards and away from each other. The screw engagement means is pivotably mounted to the first jaw by a pivot. The pivot may be a pin or a shaft connecting the screw engagement means to the first jaw. The pivot axis (i.e. the axis about which the screw engagement means rotates) is substantially parallel to the direction the jaws move to open and close the jaws. The pivot axis may be substantially parallel to the inward force provided by the jaws whilst clamped around the fastener/panel. This has the advantage that the screw engagement means is aligned with the fastener axis thereby helping extraction of the fastener. A further advantage is that the screw engagement means is aligned with the slot in the fastener to minimise the risk of stripping the fastener. A yet further advantage is that the screw engagement means can be independently rotated whilst clamped against the fastener with minimal interference from the jaw or panel.

Generally, the invention relates to a tool for extracting a screw from a panel, the tool comprising: a screw engagement means; a clamp comprising first and second opposing jaws; and a mechanism capable of adjusting the distance between the opposing jaws; wherein the screw engagement means is pivotably mounted to the first jaw; such that the screw engagement means can be rotated about its pivot whilst clamped against the screw.

More generally, the invention relates to a tool for extracting a screw from a panel, the tool comprising: a clamp comprising opposing first jaw and second jaw, wherein the first jaw comprises a screw engagement means; a mechanism capable of adjusting the distance between the screw engagement means and the second jaw, such that, in use, the tool clamps the panel with the screw engagement means engaged with the screw; wherein the screw engagement means is capable of independent rotation, such that, in use, the screw may be extracted from the panel, whilst the panel remains clamped.

Any feature in one aspect of the invention may be applied to any other aspects of the invention, in any appropriate combination. In particular device aspects may be applied to method or use aspects and vice versa. The invention extends to a device, method or use substantially as herein described, with reference to the accompanying drawings.

In all aspects, the invention may comprise, consist essentially of, or consist of any feature or combination of features.

Brief Description of the Drawings

Embodiments of the invention will now be described, purely by way of example, with reference to the accompanying drawings, in which;

Figure 1 is a schematic, side on view of a first embodiment of the invention in use.

Figure 2 is a schematic, side on view of a second embodiment of the invention in use.

The drawings are for illustrative purposes only and are not to scale.

Detailed Description Figure 1 illustrates an embodiment of the invention in which the tool 100 comprises a G clamp having a G shaped body 101. At one end of the body 101 is a fixed jaw 102 and the other end comprises a hole through with a threaded jaw 103 is pivotably mounted. The threaded jaw 103 comprises a handle 104 to enable the user to rotate the threaded jaw 103 to adjust the distance between it the fixed jaw 102. A bolt head grip 105 is pivotably mounted onto the fixed jaw 102. The internal surface of the bolt head grip 105 comprises a reverse spiral flute (not shown) designed to engage the external surface of a bolt head during torsion. The external surface of the bolt head grip 105 comprises a hex nut 106 that can be engaged by a spanner or the like in order to rotate the bolt head grip 105 about its pivot. A clamp plate 107 is pivotably mounted to the threaded jaw 103. The jaws 102 and 103 are clamped around a bolt 108 embedded in a panel 109 such that the head of the bolt 110 protrudes from the front surface of the panel 109. The slot 111 in the bolt head 110 has been stripped and therefore the bolt 108 cannot be extracted from the panel 109 using the corresponding screwdriver. The clamp plate 107 is compressed against the rear surface of the panel 109 such that the clamp plate 107 grips this surface and does not rotate as the threaded jaw 103 pivots.

In use, the jaws 102/103 are positioned around the embedded bolt 108 and panel 109. The user rotates adjusts the distance between the jaws 102/103 using the handle 104 until the clamp plate 107 engages the rear surface of the panel 109 and the bolt head grip 105 encloses over and around the bolt head 110 (Fig. 1 shows the bolt head 110 through the bolt head grip 105 wall for illustrative purposes only). Once the jaws 102/103 are securely compressed against the embedded bolt 108/panel 109, the user rotates the bolt head grip 105 counter-clockwise using a spanner to engage the hex nut 106. As torsion is applied to the bolt 108, it lifts vertically out of the panel 109. The jaws 102/103 are separated in stages (by turning the handle 104) to provide space for the bolt 108 to lift out of the panel 109 whilst maintaining sufficient compression (and therefore grip) between the bolt head grip 105 and the bolt head 110.

Figure 2 illustrates an embodiment of the invention in which the tool 200 comprises a G clamp having a G shaped body 201. At one end of the body 201 is a fixed jaw 202 and the other end comprises a hole through with a threaded jaw 203 is pivotably mounted. The threaded jaw 203 comprises a handle 204 to enable the user to rotate the threaded jaw 203 to adjust the distance between it the fixed jaw 202. A crosshead screwdriver tip 205 is pivotably mounted onto the fixed jaw 202. The tip 205 is sized and shaped to engage a corresponding slot 211 in the screw head 210 during torsion. The external surface of the tip 205 comprises a hex nut 206 that can be engaged by a spanner or the like in order to rotate the tip 205 about its pivot. A clamp plate 207 is pivotably mounted to the threaded jaw 203. The jaws 202 and 203 are clamped around a screw 208 embedded in a panel 209 such that the head of the screw 210 protrudes from the front surface of the panel 209. The clamp plate 207 is compressed against the rear surface of the panel 209 such that the clamp plate 207 grips this surface and does not rotate as the threaded jaw 203 pivots.

In use, the jaws 202/203 are positioned around the embedded screw 208 and panel 209. The user adjusts the distance between the jaws 202/203 by rotating the threaded jaw 203 using the handle 204 until the clamp plate 207 engages the rear surface of the panel 209 and the tip 205 is received by the slot 210. Once the jaws 202/203 are securely compressed against the embedded screw 208/panel 209, the user rotates the tip 205 counter-clockwise using a spanner to engage the hex nut 206. As torsion is applied to the screw 208, it lifts vertically out of the panel 209. The jaws 202/203 are separated in stages (by turning the handle 204) to provide space for the screw 208 to lift out of the panel 209 whilst maintaining sufficient compression (and therefore grip) between the tip 205 and the slot 211 .

It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention.

Moreover, the invention has been described with specific reference to a stripped bolt and a screw embedded in a panel. It will be understood that this is not intended to be limiting and the invention may be used more generally. For example, the invention may be used more generally with fasteners that haven’t been stripped or do not comprise a slot for a screwdriver or another tool. The fastener may be embedded in strips of material fastened together by the fastener. The fastener may or may not protrude from the panel at the front and/or rear surface of the panel. Additional applications of the invention will occur to the skilled person.