DEVICE FOR REMOVING WALL PLUGS OR DOWELS

Abstract: A device (10) suitable for removing plugs or dowels made of a plastic material comprises means (11) for directing a fluid jet (12) on a plug (15) housed inside of a hole (13) drilled in a surface (14). The fluid may be constituted by hot air, vapour or chemical substances.

Description: DEVICE FOR REMOVING WALL PLUGS OR DOWELS ******** TECHNICAL FIELD The present invention relates to a device for removing wall plugs which are commonly used as seats for housing screws or hooks inside of walls. More particularly the device according to the present invention provides for a simple and effective solution for quickly removing wall plugs made of a plastic material from holes made in walls and/or surfaces of any material, without damaging the surface on which the hole has been drilled. BACKGROUND ART The use of wall plugs or dowels to be housed inside of holes drilled in walls and/or surfaces of different materials is well known in the art, said plugs allowing screws or hooks inserted into said holes to be supported in a reliable way. However, while carrying out these operations the plugs may be broken inside of the hole, before inserting the screw or during its insertion, and this owing to a manufacturing fault or following to a wrong movement by the operator. Under these circumstances it is very difficult, and sometimes impossible, to remove said plug unless the hole is enlarged, thereby causing a damage to the wall surface. Another inconvenience which may occur is constituted by a wrong evaluation by the operator, who may insert into the hole a plug having a wrong dimension and which completely fills said hole; in this case it is very difficult to remove the plug. Moreover, it may happen that the screw breaks when being inserted into the plug and also in this case the removal operation can be difficult and cause serious damages to the wall surface. It may be noted that in some situations it is not possible to drill a hole in another position, since the corresponding screw should exactly be placed in the first position. In this case there is only one option, which is constituted by widening the hole by means of normal tools such as a screw driver or a drill machine; however, the new hole will have a diameter larger than the previous hole and the plug will not fit into said new hole. Consequently, the first hole has to be filled by means of concrete or stuccoworks before drilling a new hole, what causes time losses and high costs. DESCRIPTION OF THE INVENTION The device according to the present invention aims to obviate the disadvantages and drawbacks as described and to provide, thus, for a solution which is simple, cheap and easy to be used by anybody. This is achieved by means of a device having the features disclosed in the main claim. The dependent claims outline particularly advantageous forms of embodiment of the device according to the invention. According to a first form of embodiment of the present invention, a device for removing plugs made of plastic material generates a fluid jet which is advantageously hot and concentrated, said fluid jet being directly applied inside of the hole housing the plug to be removed. In order to enhance a comfortable and easy application of said jet inside of said hole, said device may have a gun or injector shape, what allows the necessary precision during the application being achieved. The fluid jet, e.g. an air jet, may be emitted at a relatively high temperature in order to soften the plastic material which constitutes the plug. In fact once the plug is sufficiently softened, it may effortless be removed from the hole, e.g. by means of a wrench or a similar to. Generally, the plugs are made of nylon® which has melting temperature of about 250°C. This means that the fluid jet may be emitted at a temperature lower than that threshold, though high enough for allowing the plastic material being softened. Furthermore, said fluid jet has to be concentrated in order not to disperse the heat in the environment. It may be noted that this operation may easily be carried out by anybody without causing any damage to the wall surface, nor efforts by the operator. According to this form of embodiment of the invention the fluid used by the device is constituted by hot air which causes the plug to be softened inside of the hole. According to another form of embodiment of the invention the air temperature is set at a higher level, in order to cause the melting of the plug. In this case the device according to the invention (which, as mentioned above, has a gun shape) is provided with means for emitting the air jet necessary for melting the plug, as well as with means for sucking the molten material from the hole. By way of example said device is provided with a motor which is driven at two different speeds in order to generate a hot air jet at two distinct temperatures, i.e. softening and melting temperatures; in this case the operator may select the best operating mode according to his hints. According to a further form of embodiment the motor of said device is realized in such a way as to generate the hot air jet when it is turning in a given direction, while it acts as a sucker for removing the molten material and any possible deposits when turning in the opposite direction. According to this form of embodiment a suitable tank is provided in order to collect the molten material as sucked from the hole. Furthermore, according to a form of embodiment the device according to the present invention is provided, at one end thereof, with a cap which is suitably shaped in order to enclose the hole inside of its contour when the cap is placed against the wall surface. This cap performs a first function of addressing towards the hole the fluid jet, as well as a second function (while the device is being used as sucker) of avoiding that molten material and/or deposits soil the wall surface. According to a further form of embodiment of the present invention, the fluid may constituted by vapour at the softening and/or melting temperature of the plug material . According to another form of embodiment of the present invention, the hot fluid jet is replaced by a suitable solvent or by an acid solution in order to remove tha plug. ILLUSTRATION OF DRAWINGS Other features and advantages of the present invention will become apparent by reading the following description of a form of embodiment of the invention, given as a non-limiting example, with the help of the figure illustrated in the attached drawing, which shows a schematical side view of a device according to the present invention . DESCRIPTION OF A FORM OF EMBODIMENT In the figure, reference sign 10 indicates a device according to the present invention. Said device 10 comprises a means 11, e.g. a gun shaped element, suitable for generating a concentrated hot air jet 12 to be directed inside of hole 13 drilled in wall 14, said hole 13 housing a plug or dowel 15 to be removed. The air jet is emitted at a temperature which is selected in order to soften the plug material . In this way the softened plug may then be easily catched and extracted, e.g. by means of a wrench. Furthermore, the figure shows a cap 16 which, when placed on wall 14, encloses hole 13 within its contour, thereby directing the fluid jet on the plug to be removed and avoiding that molten material and/or deposits coming out of the wall soil the wall surface.

Claims: CLAIMS 1. Device (10) suitable for removing plugs or dowels made of a plastic material characterized in that it comprises means (11) for directing a fluid jet (12) on a plug (15) housed inside of a hole (13) drilled in a surface (14 ) . 2. Device (10) according to claim 1, characterized in that the fluid jet (12) has a temperature suitable for softening or melting the plug material . 3. Device (10) according to anyone of the preceding claims, characterized in that the fluid (12) is constituted by air. 4. Device (10) according to claim 1, characterized in that the fluid (12) is constituted by a solvent and/or an acid solution. 5. Device (10) according to claim 1 or 4, characterized in that it comprises a sucker suitable for removing the plug (15) and cleaning the hole (13) . 6. Device (10) according to claim 1 or 4 , characterized in that it comprises a tank for collecting molten material and/or deposits and/or solvents. 7. Device (10) according to claim 1 or 4, characterized in that it comprises a cap (16) for directing the fluid jet (12) and/or enhancing the transport of the deposits towards said tank.

Inventors: COLTRO DAVIDE, COLTRO, DAVIDE
Applicants: COLTRO DAVIDE, COLTRO, DAVIDE
Application year: 1998
Main classification: B25B31
IPC codes: B25B31