EP0315287A1

EP0315287A1 - A sanding tool for manually sanding a material surface

Info

Publication number: EP0315287A1
Application number: EP88202466A
Authority: EP
Inventors: Leo Engels
Original assignee: Tiger Products BV; MULTIGOOD BV
Current assignee: TIGER PRODUCTS B.V.
Priority date: 1987-11-06
Filing date: 1988-11-04
Publication date: 1989-05-10
Also published as: NL8702653A

Abstract

A sanding tool (1) for manually sanding a material surface, comprising a supporting plate (2) having a sanding side to be turned towards the material surface to be treated, and a back, and means for retaining a sheet of sandpaper, the means for retaining a sheet of sandpaper (11) comprising a plurality of openings (6) provided in the supporting plate (2), and a corresponding number of tongues (8) attached to the supporting plate (2) on the back and extending over the openings (6) in the direction of an edge of the supporting plate.

Description

This invention relates to a sanding tool for manually sending a material surface, comprising a supporting plate having a sanding side to be turned towards the material surface to be treated, and a back, and means for retaining a sheet of sandpaper.
Sanding tools for manually sanding material surfaces are known and commercially available in many embodiments for craftsmen and do-it-yourselfers.
The sanding block mostly made from cork and having a supporting surface for sandpaper and likewise functioning entirely as a hand grip has been known from early days. The sandpaper is wound (partly) around the sanding block and held in the hand in the working position. A drawback of this known sanding block is that it is difficult to hold it firmly for a prolonged period during the sanding and that, moreover, the finger tips lie against the rough side of the sandpaper.
USP 3,975,868 discloses a sanding block having slots in which the end edges of a piece of sandpaper can be inserted. The sandpaper should be cut into a special form for that purpose and is properly retained in the slots only when a certain pressure is exerted on the sanding block with the hand.
Furthermore, various sanding blocks are known from practice that consist of two parts fitting one into the other, and between which the end edges of a piece of sandpaper can be clamped. In these sanding blocks known from practice, too, the sandpaper is clamped firmly only as long as pressure is exerted on the sanding block with the hand in a specific manner. Moreover, the form of the known sanding blocks is not adjusted to the human hand, or hardly so, so that fatigue phenomena may occur relatively quickly. Moreover, there is the risk of parts getting lost.
It is an object of the invention to provide an improved hand sanding tool which is provided with means adapted to retain sandpaper independently of a force to be exerted on the sanding tool with the hand.
To that effect, according to the invention, a sanding tool of the above described type is characterized in that the means for retaining a sheet of sandpaper comprise a plurality of openings provided in the supporting plate, and a corresponding number of tongues attached to the supporting plate on the back and extending over the openings in the direction of an edge of the supporting plate.
It is observed that US Patent Specification 3,775,923 discloses a sanding tool comprising a supporting plate having lips cut from the material of the supporting plate. On the back of the supporting plate, an edge of a piece of sandpaper folded about the supporting plate can be pushed underneath one or more lips. As the lips are cut from the material of the supporting plate itself, the lips themselves cannot sufficiently retain the sandpaper. This again makes it necessary for the lips to be pressed on the sandpaper with the hand. With a view to handling the sanding tool, there is provided a band fitted about the sanding plate in transverse direction, so that the user's hand can be inserted between the supporting plate and the band. A drawback of this construction is that the sanding tool is difficult to retain. An additional drawback is that the band on the sanding side of the sanding tool lies directly underneath the sandpaper, thereby producing a thickened portion, resulting in rapid local wear of the sandpaper and, moreover, preventing an optimum result of the sanding operations.
Some embodiments of a sanding tool according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic elevational view of the back of an embodiment of a sanding tool according to the invention;
Fig. 2 is a diagrammatic longitudinal sectional view, taken on the line II-II of Fig. 1;
Fig. 3 is a diagrammatic view of the back of a different embodiment of a sanding tool according to the invention; and
Fig. 4 shows a variant of a detail of a sanding tool according to the invention.

The sanding tool 1 shown in Figs. 1 and 2 is made preferably from a synthetic plastics material by means of injection molding aan comprises a flat supporting plate 2 having on its back a hand grip 4. In this embodiment, hand grip 4 is hollow , while partitions 5 are provided between the longitudinal walls of the hand grip so as to obtain the required strength.
The length of hand grip 4 is such that on the back of the supporting plate there remain free edge regions 3, containing four openings 6, arranged pairwise, symmetrically relative to the longitudinal median plane, and the transverse median plane, respectively, of supporting plate 2.
In this embodiment, the openings 6 are covered, except for a narrow edge slot 7, by tongues 8 extending over the openings, a portion 9 of said tongues 8 being fixedly connected to the back of supporting plate 2.
At the sanding side (Fig. 2), supporting plate 2 is coated with an elastically compressible layer 10 of a foam plastics material. In Fig. 2, 11 indicates a sheet of sandpaper of a sufficient length so that at the openings 6 folded edge portions 12 of the sheet can be pushed underneath tongues 8 and is thus retained.
In the embodiment shown, the surface of tongues 8 facing openings 6 lies substantially in the plane defined by the upper face of the supporting plate. The rough side of the sandpaper is in contact with the lower face of the tongues. It has been found in practice that such a construction normally provides for sufficient additional frictional resistance to keep the sheet of sandpaper in place during the sanding. If desired, the tongues 8 may be provided with friction-increasing means adjacent openings 6. The tongues may also be slightly thickened in the direction of the openings, e.g. bent, with the thickened portion sunk into the opening somewhat. As a result, the additional frictional resistance at the openings, by virtue of the contact between the sandpaper and the bottom side, as viewed in Fig. 2, of the free tongue portion, is increased. Alternatively, the tongues may be disposed in such a manner that the portions covering the openings extend with some bias into the openings.
The insertion of the sheet of sandpaper underneath tongues 8 at openings 6 can be facilitated, using the flexibility of supporting plate 2, by bending the free edge regions 3 thereof slightly downwards, so that the vertical dimension of edge slot 7 is increased.
In the sanding tool according to the invention shown in Fig. 3, wherein like reference numerals are used to designate parts with analogous functions to the embodiment shown in Figs. 1 and 2, the end portions 19 of the hand grip function likewise as tongues 8, so that said end portions extend over openings 7 provided at that location in supporting plate 2.
Naturally, modifications may be made to the sanding tool as discussed hereinbefore and shown in the drawing, without departing from the scope of the invention. For instance, the hand grip may be constructed in many variations. The hand grip shown may e.g. be entirely or partly solid. The tongues in the embodiment shown, as openings 6, have a releasing configuration. Angular shapes and/or shapes in which the tongues are polylobed are possible. Besides, the tongues may be larger than the openings, in particular when the tongues are partly thickened. Such an embodiment is diagrammatically shown in Fig. 4. The tongue 40 shown has a portion 41 covering an opening 6, which is larger than opening 6 and a continuation of a portion 42 lying on supporting plate 4. The portion 41 covering opening 6 has a thickening 43 extending into opening 6, so that a piece of sandpaper lying underneath the tongue is retained particularly firmly.

Claims

1. A sanding tool for manually sanding a material surface, comprising a supporting plate having a sanding side to be turned towards the material to be treated, and a back, and means for retaining a sheet of sandpaper, characterized in that the means for retaining a sheet of sandpaper comprise a plurality of openings provided in the supporting plate, and a corresponding number of tongues attached to the supporting plate on the back and extending over the openings in the direction of an edge of the supporting plate.

2. A sanding tool as claimed in claim 1, characterized in that the tongues leave an edge region of the associated openings clear.

3. A sanding tool as claimed in claim 1, characterized in that the tongues cover the openings and an edge region around the openings.

4. A sanding tool as claimed in any one of the preceding claims, characterized in that the tongues are provided with friction-increasing means on the surface facing the openings.

5. A sanding tool as claimed in any one of the preceding claims, characterized in that at least a part of the surface of the tongues facing the openings extends into the openings.

6. A sanding tool as claimed in claim 4 or 5, characterized in that the portion of the surface extending into the openings is formed by a thickened tongue portion.

7. A sanding tool as claimed in claim 4 or 5, characterized in that the portion of the surface extending into the openings is formed by a bent tongue portion.

8. A sanding tool as claimed in claim 4 or 5, characterized in that the tongues extend into the associated openings with some bias.

9. A sanding tool as claimed in any one of the preceding claims, characterized in that the supporting plate has two opposite end edge regions and adjacent each of the end edges a plurality of openings arranged symmetrically relative to both a longitudinal axis and a transverse axis of the supporting plate, with the tongues extending from the edge of the openings opposite the associated end edge over the openings.

10. A sanding tool as claimed in any one of the preceding claims, characterized in that the supporting plate is coated on the sanding side with a layer of elastically compressible material.

11. A sanding tool as claimed in any one of the preceding claims, characterized by a hand grip on the back of the supporting plate.

12. A sanding tool as claimed in claim 11, characterized in that the hand grip is an elongate hand grip extending longitudinally of the supporting plate.

13. A sanding tool as claimed in claim 12, characterized in that the ends of the hand grip extend over corresponding opening in the supporting plate and function as tongues for retaining a sheet of sandpaper.

14. A sanding tool as claimed in any one of the preceding claims, characterized in that the supporting plate is slightly flexible.