HAND GLASS-PAPERING PAD PROVIDED WITH A SUCTION CHAMBER THEREIN OR GENERALLY A FLUID PASSAGE

Abstract: A pad of flexible and resilient material for hand smoothing surfaces by abrasive paper has inside a fluid passage in communication with the outside by means of a sleeve connected, through a hose, with a vacuum source or a fluid feed, as well as with several through holes on the lower processing surface. In case of air suction also some vent holes are provided to the outside, having a smaller cross-section area with respect to the actual suction holes and within said passage, immediately after said connection with the outside, there is formed a vacuum balance chamber.

Description: "HAND GLASS-PAPERING PAD PROVIDED WITH A SUCTION CHAMBER THEREIN OR GENERALLY A FLUID PASSAGE" The present invention relates to a pad, also called "sanding mop" for hand processing, with abrasi- ve paper, without any machine, surfaces to be rough- shaped, smoothed, finished or cleaned up from resi¬ dual paints or others, with a fluid path formed therein in order to suck or drain with the fluid itself those powders generated during processing. It is known the use, at present more and more reappraised, of pads in a soft and flexible material, with the handle being elastic or adjustable on the upper surface, also having on the opposed side a coupling means for a replaceable abrasive member. In fact, in order to glass-paper or generally process with abrasive any surface of metal, wood or other material, often provided with irregularities, a flexible pad or manual "mop" can match therewith, being capable of following possible recesses of the surface with a sensitivity that only a man hand can give, with respect to the use of portable mechanical devices bearing a rotating abrasive disk. However, whereas devices of this type are generally provided with a subsidiary suction box, although not perfectly efficient owing to the imperfect matching of the abrasive surface with that to be processed, as well as of the loss (leackage) of air between said suction box and the rotating disk, the pads to be used by hand show on the contrary the drawback that powders are not drained away. In order to overcome this inconvenience, pads or manual use have been manufactured and used, such as that being object of US Patent No.4184291, provided with holes on the lower surface, which are all commu¬ nicating with only one central collecting hole on the upper surface, e.g. passing through a projecting portion in a spongy material like that forming the pad, all being housed in a box fixed to the pad itself and provided with a hose connecting with an outer vacuum source. This box, rather " bulky, shall of course provide also the handling means of the pad itself. However this is not practical, as in this way the advantages of the manual pad are failing, since the device flexibility is reduced, as well as its ability of closely following the asperities of the surface to be processed, thanks to the unique manual sensitivity of the operator. Therefore the drawbacks of machine processing are still experien¬ ced, with a partial suction of powders, without having on the other hand the advantages of a quicker operation, less tiresome for man. An object of the present invention is therefore that of providing a pad of the above-mentioned type, to be used by hand, comprising, formed therein, means for removing the powders produced during working, so as not to lose, during its utilization, the main features of flexibility and softness, thus being able to perfectly follow all the surface configura¬ tions, without the encumbrance of outer auxiliary means such as the above-mentioned suction chamber involving more rigidity, while ensuring at the same time a perfect removal of powders both through sue- tion and by wet way . This is obtained by providing within the pad, which will be preferably formed as of "sandwich-type" in at least two coupled portions, a fluid path commu- nicating both with some holes passing through the lower outer surface of the pad, and with a manifold connecting with an outer hose, said connector passing through one of the side surfaces of the pad. According to a preferred embodiment, powders are removed by suction and the path of sucked air is obtained by removal of material from a central one among three elements forming, when coupled and over¬ lapping to each other, the pad itself, said path communicating to the outside not only through the holes formed in the lower element of the "sandwich", but also through side vent passages, having a smaller cross-section than that of the suction holes. In the central element of the fluid path there will be preferably formed also a suction chamber for distribu- ting and balancing the vacuum levels in the region immediately confronting the connector communicating with the suction at the outside. According to another embodiment the removal of powder occurs in a wet environment, whereby the fluid is water and its path within the pad may be provided advantageously by means of a small tube embedded in the pad itself, which in this case could be formed of even only two elements mutually coupled, said tube having outlet holes corresponding to the through holes to the outside in order to bring mois¬ ture to the surface being processed. These and additional objects, advantages and features of the above-mentioned, manually operated pad for processing surfaces with abrasive will be clear from the following detailed description of some preferred embodiments thereof, given by way of non-limiting examples, with reference to the annexed drawings in which: FIGURE 1 shows an exploded view of a preferred embodiment of pad according to the present invention with suction incorporated therein; and FIGURE 2 shows a perspective, partially sectio¬ nal view of another embodiment of pad according to the invention, with removal of the powders in a wet environment. With reference to the drawings a preferred embodiment of pad, as shown in fig.1, provides for an integrally incorporated suction and a vacuum path formed by means of material removal from the central one of three overlapping elements, coupled to each other in a "sandwich-like" manner, preferably in a spongy or expanded material, of which the pad accor¬ ding to the Invention is made. This type of material ensures softness and flexibility of the pad. The three elements or layers consist respective¬ ly of an upper layer 1 to which a non-rigid handle 10 is fixed, an intermediate layer 2 in which a fluid path 20 is formed, in this case for suction, as well as a connector 21 with an outer hose (not shown) and a lower layer 3 being crossed, through its thickness, by through holes 5 and having on the lower surface coupling means for a piece, preferably replaceable, of abrasive paper 4 also formed with corresponding holes 5'. Handle 10 may be formed as any strip of flexible material, possibly of elastic character in order to be better adapted to hands of different size. Prefera- bly it is formed of two strips respectively fixed to layer 1 at an end portion thereof, or only one strip passing through two slits 11, 11a with the free ends mutually joined in an easily adjustable manner, e.g. being in "Velcro" material for an easy and reliable fastening. The upper layer 1 may have a smaller thickness than the other two layers. The intermediate layer 2 is shaped, by removal of material, such as by means of hollow punching, so as to give rise to a fluid path 20, in this case for sucked air. In particular, with reference to fig.1 a first recess 23 is obtained with parallel walls for housing the connector 21 communicating with the outer hose. Said recess 23 is connected to the inside with the actual suction path 20 comprising two pa- rallel, elongated channels 25, 25a which extend themselves to the direction of the longer sides of layer 2 at a given distance therebetween, thus forming a hollow or chamber 27 in front of recess 23, prefera¬ bly defined to the inside by an arc-shaped wall 22 separating the two channels 25, 25a. Still according to a preferred embodiment of the present invention the ends of said two channels, which are more distant from said chamber 27, stop before reaching the outer surface of layer 2 but are however in communication with the outside through grooves 29 preferably having a U-shaped cross-section, which are also obtained through partial removal of material, but without reaching the lower surface of the layer. Similar grooves, preferably having the same cross-section, are provided sidely from said channels 25, 25a, thus coming into communication to the outside also from these positions. In the drawing these lateral grooves have been shown in a number of two at each side of the layer but of course they could be provided in a different number. Coming now to the last lower layer 3, which has also the same size as the other two layers, at least as far as the two greatest dimensions are concerned, it shows two arrays of through holes 5, each of said arrays being, upon coupling, directly corresponding to the two channels 25, 25a of the intermediate layer 2. It will be appreciated that, instead of the two arrays of holes 5 there could be provided at the same position two elongated slots having the same effect as to suction. It should also be noted that the width of channels 25, 25a is a function of the diameter of holes 5 or the width of the possibly replacing slot. The number of holes is preferably eight, as shown in the drawing, but it could be also different. The lower surface of layer 3, not visible in the drawing, will be then sheathed with a layer of micro-hooks of "Velcro" type in order to retain the abrasive material 4, provided with holes 5' and having a particular velvet-like surface at the inside, thus allowing this type of fastening, as already known in the trade. However coupling with the abrasive material could be of whichever different type within the reach of a techni¬ cian. Also referring to the upper surface of layer 1 , this could be wholly made of micro-hooks for a "Velcro" fastening with a glove of fabrics worn by the operator, in this case the handling strip 10 being superfluous. By a suitable mutual coupling of the three layers 1,2 and 3, a compact assembly is obtained firmly retaining at the inside the connector 21, while keeping unchanged the softness and the flexibility features which are typical of the mate¬ rial. When joining the connector 21 to an outer suction source through a suitable flexible hose, the powder produced during the operation in the region of lower surface of layer 3, is almost completely sucked into the pad inside through holes 5 and path 20 to be drawn away by suction stream along the same connector 21 and the hose of communication to the outside. The presence of grooves 29 on three sides of the pad allows for a venting action and an air intake also in this zone, thus avoiding that air is entirely sucked through holes 5, only with consequent adhering of pad itself onto the surface to be processed. It is important that the side vent holes 29 lead inwar- dly each near a suction hole 5 and that the overall cross-section area through the side vent holes 29 is less (about 70%) than the total cross-section area of holes 5, or better holes 5' of abrasive. Coming now to figure 2, another embodiment of the pad according to the present invention is shown, in which the same parts as those of figure 1 are represented with the same reference numerals. Here the powders are removed by wet instead of suction. Similarly to figure 1 , the pad is ormed of three coupled members or layers overlapping to each other, of which the upper one 1 carries a handle means 10, the lower one 3 is provided with through holes 5, in this case for outflow of water which, flowing through the abrasive material 4, having also corresponding holes, draws therewith the powders generated in the region of working surface. There is again an inner path of fluid 20a, which can consist of a channel formed by removal of material in the intermediate layer 2 or, as shown in figure 2, is provided by a tubular body forming a loop from a sleeve 21a of connection with an outer conduit (not shown) for water feeding. The tubular body 20a is provided with holes 24 at each through hole 5 in the lower layer, whereby water, having a given pressure, due to a slight head level, outflows from tubular body 20a, with parallel streams throughout holes 24, which are possibly provided in number of four as well as the underlying holes 5 and obviously also the corresponding holes 5' in the abrasive material 4. It will be appreciated that holes on the pad bottom, formed through the abrasive material, could even be in a different number with respect to holes 24, when providing e.g. an additional central hole receiving water either by spreading throughout the spongy material or by means of radial passages con¬ necting said central hole with the holes arranged circumferentially on the tubular body 20a. It is clear that in this embodiment based on a wet solution the overlapping layers could be only two, with the tubular body 20a housed in correspon- ding seats formed partially in the lower layer and partially in the upper one. Reverting now to the embodiment of figure 1 , it should be noted that the purpose of said suction chamber 27 is that of rendering uniform and constant the pressure during the whole operation and wherever along the path 20. Such a chamber will have a confi¬ guration defined by an arc of circumference shape, for example semicircular, of said wall 22 limiting the same from opposite side to recess 23- Finally it will be noted that, with the embed¬ ded suction chamber according to the present inven¬ tion, air leackages are prevented, thus obtaining an excellent suction with a less heavy pneumatic duty, what allows to reduce the operating expenses and costs of construction. In fact the air volume being sucked by the known rotating devices is largely higher than that required for operation of the pad according to the invention. Possible additions and/or modifications could be brought by those skilled in the art to the above- described and illustrated embodiments of the hand-ope¬ rated pad for processing with abrasive paper, accor¬ ding to the present invention, without exceeding the scope of the invention itself. In particular the outer shape of the pad could vary, such as to result e.g. of circular cross-section or the shape and direc¬ tion of the inner path 20 of fluid, both when the fluid is sucked air, and in case of water in the wet type operation.

Claims: CLAIMS 1. A pad of soft and spongy material, provided on its lower surface with abrasive means (4) for hand glass-papering work surfaces, comprising in its upper portion handle flexible means (10), characteri- zed by compring in its inner portion, formed of at least two layers (1,2,3) of said material being coupled to each other, a fluid path (20,20a) communi¬ cating both with a number of holes (5) passing through the outer surface of the pad lower layer (3) in correspondence with the same number of holes (5') through the abrasive layer (4), and with a fitting connector (21) being joined, through a flexible hose, to an outer suction or fluid feed source. 2. A pad according to claim 1, characterized in that said outer source is of suction and said path (20) of sucked air comprises recesses and groo¬ ves formed by removal of material from the interme¬ diate layer (2) among three layers forming the pad, with channels (25,25a) in communication with said holes (5). 3. A pad according to claim 2, characterized by further comprising side holes or grooves (29) having a substantially U-shaped cross-section, of a smaller area than the cross-section of said holes (5,5') and having the function of side vents or air intakes. 4. A pad according to claim 2 or 3, characteri¬ zed by comprising, in the intermediate layer thereof (2), immediately in front of an inlet zone (23) of the fitting (21) communicating to the outside, a chamber of balance and distribution of pressure (27) , communicating with said channels (25,25a) and defined at the side opposed to said zone (23) by a concave wall (22) of the intermediate layer (2). 5. A pad according to any one of claims 2-4 characterized in that said holes (5) of layer (3) are in number of eight, arranged in two arrays of four aligned holes, parallel to each other and to the pad sides which are nearer to that in which the connector (21) is fitted, in correspondence with said channels (25,25a) also parallel to said sides. 6. A pad according to claim 1, characterized in that said fluid path (20a) in its inside is subs¬ tantially loop-shaped, except from some openings (24) communicating with said holes (5) of lower layer (3), said path (20a) being fed with water through a connector (21a) in communication with the outside. 7. A pad according to claim 6, characterized in that said path (20a) is formed as a tubular body of a substantially circular shape, communicating with said connector (21a) and provided with holes (24) in correspondence with said holes (5,5') in the lower layer (3) and in the abrasive material (4). 8. A pad according to claim 6, characterized in that said fluid path (20a) is formed as a chan¬ nel-shaped passage obtained by removal of material in said intermediate layer (2). 9. A pad according to claim 6, characterized in that holes (5,5') are in a number greater than holes (24) along the path (20), there being provided small passages for feeding water from said holes (24) to those holes (5) which are not directly fed thereby. 10. A pad according to claim 1, characterized by comprising a handle (10) on the upper layer (1), formed of at least one strip of adjustable length in a material provided with "Velcro" micro-hooks. 11. A pad according to claim 1, characterized in that said outer surface of upper layer (1) is formed of material provided with "Velcro" micro-hooks. 12. A pad according to claim 2, characterized in that said holes (5,5') are respectively formed as a single pair of elongated slots, each corresponding to one of said channels (25,25a).

Inventors: GALASSI CARLA, SCOLLO GIOVANNI, GALASSI, CARLA, SCOLLO, GIOVANNI
Applicants: GALASSI CARLA, SCOLLO GIOVANNI, GALASSI, CARLA, SCOLLO, GIOVANNI
Application year: 1992
Main classification: B24D15
IPC codes: B24D15