PORTABLE ELECTRICAL POLISHING MACHINE TOOL FOR THE MACHINING OF SURFACES OF MATERIALS WITH SIMPLIFIED SUCTION OF THE DUST PRODUCED

Abstract: In an electrical portable polishing machine tool for the machining of surfaces of materials essentially composed by a body (10, 11, 12) encasing a vertical-axis electrical motor, (13) provided with gripping handle (20) and assembled, through interposed elastic elements, (34) on a polishing plate (18) onto which an abrasive sheet (19) is placed, both said plate (18) and said sheet (19) being provided with a plurality of apertures (36) for the passage and the suction of the dust produced by said surface machining, in the lower part of such body (10, 11, 12)a fan (27) is placed, which is operatively controlled by a kinematic couple (29, 30) driven by the shaft (14) of said motor,(13) such as to generate a turning speed of said fan (27) greater than that of said shaft (14) of said motor, (13) said fan (27) being positioned within a chamber (22) connected both to said plurality of openings (36) and to an outwards suction duct. (23)

Description: Disclosure The present invention relates to an electrical port able polishing machine tool for the machining of surfaces of materials with simplified suction of the dust produced during the abrasion operative step. Tool machines of this type are known, which essential ly comprise a body, enclosing a vertical-axis electrical motor, provided with a handle and assembled, by means of the interposition of elastic elements, on a polishing plate on which an abrasive sheet is positioned. Said plate and said abrasive sheet are provided with a plurality of apertures for the passage and the suction of the dust created by the polishing action by the same abrasive sheet. The motion of the polishing plate is accomplished, in a known way, by means of an eccentric element provided and fastened onto the shaft of the electrical motor, and guided inside the same plate, so as to obtain an orbital movement. During the polishing operation, the dust produced tends to diffuse or to remain on the working surface, so disturbing the visibility of the piece being machined and polluting the working environment with considerable troubles for the operator. To the purpose of obviating these drawbacks, it has already been proposed it to equip the polishing tool machines with a suction system to collect and carry far away the dust producing during the machining. Such systems envisage e.g. suitable outer pipes with suction ports and suitable connectors for the connection to suction ducts incorporated in the machine, As an instance, through the plurality of apertures provided in the polishing plate, dust is sucked towards a plurality of channels provided above the plate and inside the body of the machine towards a duct conveying them towards a suction means. A so structured suction system has however the draw- back of being depending on the outer suction means. By envisaging on the contrary a fan keyed on the driving shaft as an aid for the suction, a better suction action is obtained, which is however constrained to the speed (rpm) of the same motor, Purpose of the present invention is to provide a polishing tool machine equipped with a really efficacious suction system, capable of withdrawing totally and quickly the dust as formed. In view of this purpose according to the present invention an electrical portable polishing machine tool is accomplished for the machining of surfaces of materials essentially composed by a body encasing a vertical-axis electrical motor, provided with gripping handle and assembled, through interposed elastic elements, on a polish ing plate onto which an abrasive sheet is placed, both said plate and said sheet being provided with a plurality of apertures for the passage and the suction of the dust produced by said surface machining, characterized in that in the lower part of such body a fan is placed, which is operatively controlled by a kinematic couple driven by the shaft of said motor, such as to generate a turning speed of said fan greater than that of said shaft of said motor, said fan being positioned within a chamber connected both to said plurality of openings and to a suction duct' to the outside. The structural and functional characteristics of a machine according to the present invention shall be better understood from the following exemplifying and not limitative disclosure, referred to the attached schematic drawings, wherein: Figure 1 is a side elevation view of a machine accord ing to the invention, Fig. 2 is an elevation view equivalent to that of fig. 1, partly in section, Fig. 3 is a sectional view according to the line III III of fig. 1, and Fig. 4 is a sectional view according to the line IV IV of fig. 1. As shown in fig. 1 and 2, an electrical portable polishing machine comprises essentially a body formed by an upper cap 10, by a central portion 11 and by a lower portion 12, rigidly linked to each other so as to constitute said single body supporting a vertical-axis electrical motor 13. The shaft 74 of said motor 13 bears solidly constrain ed and operatively linked thereto an eccentric element 15, acting within a complementary seat 16 of a covering portion 17 for a polishing plate 18 onto which an abrasive sheet 19 is positioned and fastened in a known fashion. From the central portion 11 protrude: on one side a gripping handle 20 and on the other side a gripping and pressure-exerting element 21. In the lower portion a chamber 22 is provided, from which a duct 23 extends, which is operatively connected with a discharge tubular element 24, ending into a connector or fitting 25, said tubular element 24 constituting the lower portion of the gripping handle 20. Said gripping handle 20 indeed, essentially having a reversed-U shape (fig. #), is closed by said tubular element 24, and houses additionally a cable 26 for the feeding of the motor 13. The chamber 22 contains a fan 27 which receives its rotary motion from a shaft 28 solid with a first gear wheel 29, operatively coupled to and driven for rotation by a second gear wheel 30 keyed onto the shaft 14 of the motor 13. Said chamber 22 is provided in its lower portion with an aperture 31 connected, via an elastic bellows-shaped element 32, with a port 33 provided in the upper portion of the cover 17 of the polishing plate 18. Between said lower portion 12 and said cover 17 a plu rality is provided of column-shaped elastic elements 34, suitable to allow the orbital motion of the same plate and to prevent it from rotating. The polishing plate 18 is provided with a plurality of apertures 35 in correspondence of which corresponding apertures 36 present or provided in the abrasive sheet 19 are positioned. Said plurality of apertures are connected to a chamber 37 defined between said cover and said plate, and con nected with the port 33. When the electrical polishing machine comes in contact with the surface of the material to be polished, the orbital movement of the polishing plate 18 and of the related abrasive sheet 19 positioned onto it cause the formation of dust. The dust formed is sucked, according to the arrows of fig. 2, from the apertures 36, 35 passes into the cham ber 37 and through the port 33, the bellows 32 and the aperture 31 it comes into the chamber 22 wherein the fan 27 is housed. From said chamber the dust is then sent through the duct 23 and the tubular element 24 to a collecting means, which may be either positioned solid with the connector 25 or placed in a remote site and connected with it via a flexible pipe, not shown. It results particularly advantageous the provision of the two gear wheels 29, 30, or of whatever other couple of kinematic elements, such as e.g., toothed wheels or pul leys with related transmission belts, such as to allow the fan 27 to turn at a higher speed than the motor 13, thus allowing a considerable suction. Advantageously, the greater or lesser adhesion between the abrasive sheet and the material under machining, by influencing the motor speed, causes consequently an equal adjustment of the turning speed of the fan 27, thus varying the suction efficiency. It is also advantageous to note that the tubular element 24 besides acting as suction duct, performs the fun ction of lower closure of the gripping handle 20 and is hence suitable to be easily fitted to it.

Claims: Claims 1. Electrical portable polishing machine tool for the machining of surfaces of materials essentially composed by a body encasing a vertical-axis electrical motor, provided with gripping handle and assembled, through interposed elastic elements, on a polishing plate onto which an abrasive sheet is placed, both said plate and said sheet being provided with a plurality of apertures for the passage and the suction of the dust produced by said surface machining, characterized in that in the lower part of such body a fan is placed, which is operatively controlled by a kinematic couple driven by the shaft of said motor, such as to generate a turning speed of said fan greater than that of said shaft of said motor, said fan being positioned within a chamber connected both to said plurality of openings and to an outwards suction duct. 2. Machine tool according to claim 1, characterized in that said kinematic couple is essentially constituted by two gear wheels. 3. Machine tool according to claim 1, characterized in that said lower portion of said body shows additionally a duct connected on one side with said chamber, and on the other side with a tubular element positioned solid with said gripping handle. 11. Machine tool according to claim 1 and 3, characterized in that said gripping handle is of reverse-U shape and houses within its lower portion said tubular element, which acts as a closure for it. 5. Machine tool according to claim 2, cha acterized in that a first gear wheel is positioned as cc strained to a shaft freely rotating within said lower portion of said body, said shaft bearing said fan keyed thereto, said first gear wheel being driven for rotation by a second gear wheel keyed onto the shaft of said motor.

Inventors: VALENTINI, GUIDO
Applicants: VALENTINI, GUIDO
Application year: 1986
Main classification: B24B23
IPC codes: B23Q11, B24B55