WO2006075006A1

WO2006075006A1 - Polishing block

Info

Publication number: WO2006075006A1
Application number: PCT/EP2006/050147
Authority: WO
Inventors: Tomas Arnerdal
Original assignee: Anza Ab
Priority date: 2005-01-12
Filing date: 2006-01-11
Publication date: 2006-07-20
Also published as: SE529005C2; NO336760B1; DE112006000189T5; NO20073502L; GB2435799B; GB0713309D0; SE0500070L; DK200701028A; DK178267B1; FI126454B; GB2435799A; MY145499A; FI20070544A

Abstract

A polishing block (100) comprises a handle (110) connected to a ground plate (200), a polishing paper plate (400) and connection means for connecting said polishing paper plate (400) to said ground plate (200). A polishing paper can be clamped between said polishing paper plate (400) and said ground plate (200) and a tilt mechanism (130, 130', 210, 210') allows a tilt position between said handle (110) and said ground plate (200) to be altered.

Description

POLISHING BLOCK

FIELD OF THE INVENTION

The present invention relates to a polishing block comprising a handle connected to a ground plate, a polishing paper plate and connection means for connecting said polishing paper plate to said ground plate. A polishing paper can be clamped between said polishing paper plate and said ground plate.

PRIOR ART For polishing operation of e.g. wood, metal, gypsum boards, paint, lacquer, etc, a preferred choice has for long times been to use a polishing paper, which is a paper or other "soft" material, e.g. cloth, provided with abrasives on at least one side. Depending on the desired surface, different so called grits (i.e. abrasive grain size) can be used; if a fine surface is desired, a fine grit is used, and if a coarse surface is desired, a coarse grit is used.

For some applications, it is preferred to suspend the polishing paper by simply wrapping it once and thereafter hold it by hand. For most applications, it is however preferred to suspend the paper with some kind of polishing block; in its most uncomplicated form, such a block can comprise a box-shaped body of cork or plastic foam; the paper is wrapped around the block and held on place by hand applied force.

As can be understood, it is tiresome to hold the paper by hand; hence, polishing blocks allowing the paper to be fastened has been developed; such blocks generally comprise a ground plate connectable to a polishing paper plate; the polishing paper is wrapped around the polishing paper plate, whereupon the ground plate and the polishing paper are connected, which squeezes the paper between the plates. This type of blocks is usually used with either a fixed handle for hand polishing or a totally free-moving handle for polishing with an extension shaft. The most common way to connect the ground plate and the polishing paper plate is to use a screw-nut assembly. This solution constitutes a problem, e.g. since there is a risk that the screw disappears when the paper needs to be exchanged; it is also time consuming to turn the screw to tighten it.

Furthermore, there is a problem concerning the fixed handle for hand polishing; in corners, it is often troublesome to reach in with the polishing block.

SUMMARY OF THE INVENTION

The present invention solves these and other problems by a tilt mechanism allowing a tilt position between the handle and the ground plate to be altered. It is preferred if the tilt between the ground plate and the handle has three discrete positions, since it is convenient to be able to use one upright position and two sideways tilted positions. Further, it is preferable if the angle between two of the three discrete positions is 45 degrees. The problem with nuts that gets lost is solved in that said ground plate is connected to said paper holding plate by at least one hook projecting from said paper holding plate and being arranged to engage at least one locking means provided in the ground plate.

A lock knob is adapted for engagement with said at least one hook.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be explained by means of a description of a preferred embodiment with reference to the appended drawings, wherein; Fig. 1 is an exploded perspective view of a polishing block with a variable handle according to the present invention,

Fig. 2 is perspective view showing different handle positions for the polishing block of Fig. 1,

Figs. 3 A, 3B and 3C are section views of the polishing block and handle of fig 1, wherein the handle is shown in three different positions,

Figs. 4A, 4B and 4C are partial perspective views of a locking device according to the present invention shown in a locked, an unlocked and an open position, respectively, and

Figs. 5 A, 5B and 5C are section views showing the locking device of Figs 4A-C in corresponding positions.

DESCRIPTION OF A PREFERRED EMBODIMENT

In Fig. 1, a variable polishing block 100 according to the present invention is shown in an exploded perspective view. The polishing block 100 comprises a handle 110, which in turn comprises a grip portion 115, a front stanchion 120, and a rear stanchion 120'. Both stanchions 120, 120' end with tilt mechanism portions 130, 130', respectively. The tilt mechanism portions comprise central shafts 140,140', and gliding surfaces 150, 150' provided with ridges 160, 160'. The polishing block 100 comprises further a ground plate 200, which is provided with receiving means 210, 210' for the tilt mechanism portions 130, 130', respectively. The ground plate 200 is also provided with locking means 220, 220'. The locking means comprise two elongate shoulders 240, 245, which are designed to be guided in corresponding recesses 310, 315 of a lock knob 300. Lastly, a paper holding plate 400 is shown. It comprises two hooks 410, 410', which cooperate with the locking means 220, 220', respectively, in a way that will be described later.

In Fig. 2, the polishing block 100 is shown in an assembled state. Three different handle positions are shown; with solid lines, the handle is shown in an upright position; two tilted positions are shown with dash-dotted lines. Figs 3 A to 3B show the relationship between the tilt mechanism portions 130, 130' and the receiving means 210, 210'. The receiving means 210, 210' each comprise three recesses 230A, 230B, 230C, which are adapted to accomodate the ridges 160 and 160' depending on desired tilt for the handle 110 with respect to the ground plate 200. As can be seen, the ridges 160, 160' are hosted in recess 230A in Fig 3 A, in recess 230B in Fig 3B and in recess 230C in Fig 3C, corresponding to handle tilts of 45 degrees right, upright and 45 degrees left, respectively. In Figs 4A-4C and 5A-5C, the function of the control knob 300, the locking means 220' and the hook 410' is shown. Figs 4 A to 4C are perspective views and Figs 5A- 5C are section views; Fig 4A corresponds to Fig 5A, Fig 4B to Fig 5B and 4C to 5C. Figs 4A and 5A show the relationship between the control knob 300, the ground plate 200 and the paper holding plate 400 in a locked position; as can be seen in Fig 5A, a knob hook 320 engages the hook 410' of the paper holding plate 400, hence locking the paper holding plate 400 to the ground plate 200. In this position, an end region of a polishing paper (not shown) can be clamped between the ground plate 200 and the paper holding plate 400.

Figs 4B and 5B show the relationship between the control knob 300, the ground plate 200 and the paper holding plate 400 in an unlocked position; as can be seen from Fig 5A, the lock knob is in a position where the knob hook 320 no longer is in engagement with the hook 410, hence releasing the paper holding plate 400 from the ground plate 200.

Figs 4C and 5C, finally, show the ground plate 200 and the paper holding plate taken apart in the unlocked position of Figs 4B and 5B. Now, the assembly for the variable polishing block 100 will be described; in a first assembly step, the tilt mechanism portions 130, 130' are pressed into the receiving means 210, 210', into either of the positions shown in Figs 3A to 3C During this assembly step, the central shafts will "click" into the receiving means 210, 210', hence creating a permanent connection between the tilt mechanism portions and the receiving means. This will lock the handle in a specific position with respect to the ground plate 200, so that the ridges 160, 160 is in engagement with either of the recesses 230A, 230B or 230C; if a sufficiently large force is applied to the handle 110, the ridges 160, 160' will be forced out of engagement from either of said recesses, allowing the ridge to glide to another recess, hence altering the position of the handle with respect to the ground plate 200.

In a second assembly step, a polishing paper is wrapped around paper holding plate 400; here, it is important that polishing paper reaches all around the side of the paper holding plate 400 that not faces the ground plate 200 (i.e. the side opposite of the side from which the hooks 410, 410' projects, and further almost reaches to the hooks 410, 410'.

In a third assembly step, the hook 410 is inserted through the locking means 220, whereupon the ground plate is pulled "backwards", i.e. in the direction towards the locking means 220', in order to secure the hook 410 to the locking means 220. In a fourth, and final, assembly step, the user ensures that the lock knob is in the open position (according to any of the figures 4B, 4C, 5B or 5C); if not, the user puts the lock knob in such a position. Thereafter, the hook 410' is put into engagement with the locking means 220'; the lock knob is moved into the closed position (Figs 4A and 5A), whereupon the polishing paper will be clamped between the paper holding plate 400 and the ground plate 200, which will be locked to one another according to figs 4A and 5A.

After the fourth assembly step, the variable polishing block 100 is ready for use; the handle can be put in three different positions. This facilitates polishing of surfaces near e.g. corners; should the handle be fixed, it would be more difficult to reach into the corner.

As can be understood, there are many possible variations that can be made without departing from the scope of the claims; one such variation could be to angle the handle stanchions 120 in the "backward" direction, i.e. toward the lock knob 300; since the largest force generally is applied during the "forward" motion of a polishing process, such tilting of the stanchions 120 would decrease the rotational force applied to the connection between the receiving means 210 and the tilt mechanism portions 130, 130'.

The connection between the receiving means 210 and the tilt mechanism portion 130, 130' requires a certain amount of resilience in order to produce a position shifting force that is neither too large nor too small; in the preferred embodiment, this resilience is achieved by providing a gap 190 (Fig 3B) under the ridge 160; this gap will allow the ridge to move out from either of the recesses 230A, 230B, 230C, and thereafter glide to another of the recesses 230A, 230B, 230C if a tilt position of the handle with respect to the ground plate is desired. Further, in the described embodiment it is only possible to put the handle in three tilt positions, wherein there is an angular difference of 45 degrees between the positions; it is however nothing that excludes that more than three tilt positions can be arranged; the only necessary measure that has to be taken to achieve this is to arrange more than three recesses 230A, 230B, 230C. Moreover, it is also possible to use the variable handle of the present invention with a polishing block using conventional fastening between the ground plate and the paper holding plate. Such conventional fastening generally comprises a screw-nut assembly, and is well known by persons skilled in the art. Finally, some words regarding preferred materials for the polishing block. The preferred material is a thermoplastic, e.g. poly propene or poly propylene (PP), poly vinyl chloride (PVC), poly ethylene or the like; such plastics can be designed to attain the desired properties regarding stiffness, weight and colour. The desired material properties for the different components vary significantly; the paper holding plate should preferably be as stiff as possible, yet not too heavy; to this end, there might be a stiffening pattern on the side of the plate that faces the ground plate. A major advantage regarding thermoplastics is that they can be injection moulded, which is a very fast and efficient manufacturing method. The desired material properties for the ground plate and the handle is not as straight- forward as for the paper holding plate; as mentioned, some resilience is necessary in order to enable shifting between different handle positions. Hence, it is preferred with a material that is not as stiff as the material of the paper holding plate. As can be understood, there are several obvious modifications possible without departing from the scope of the invention; one such obvious modification could be to replace the ridges 160, 160' with recesses, and simultaneously replace the recesses 230A, 230B and 230C with ridges corresponding to the recesses replacing the ridges 160, 160'; the same effect would be achieved. This is only one obvious possible modification of the invention, the scope of which should only be defined by the appended claims.

Claims

1. A polishing block (100) comprising a handle (110) connected to a ground plate (200), a polishing paper plate (400) and connection means for connecting said polishing paper plate (400) to said ground plate (200), wherein a polishing paper can be clamped between said polishing paper plate (400) and said ground plate (200), characterised by a tilt mechanism (130, 130', 210, 210') allowing a tilt position between said handle (110) and said ground plate (200) to be altered.

2. The polishing block (100) according to claim 1, wherein the tilt between said ground plate (200) and said handle (110) has three discrete positions (230A, 230B,

230C).

3. The polishing block (100) according to any of the claims 1 or 2, wherein the angle between two of said three discrete positions (230A, 230B, 230C) is 45 degrees

4. The polishing block (100) according to any of the preceding claims, wherein said ground plate (200) is connected to said paper holding plate (400) by at least one hook (410, 410') projecting from said paper holding plate and being arranged to engage at least one locking means (220, 220') provided in the ground plate.

5. The polishing block (100) according to claim 4, wherein at least one of said locking means (220, 220') comprises a lock knob (300) adapted for engagement with said at least one hook (410, 410').

6. The polishing block (100) according to any of the preceding claims, wherein the tilt mechanism (130, 130', 210, 210') comprises receiving means (210, 210') adapted for accommodating tilt mechanism portion (130, 130'), wherein the receiving means each comprises at least two recesses (230A, 230B, 230C) for accommodating at least one ridge (160, 160') and wherein the handle position varies depending on which recess (230A, 230B, 230C) that accommodates the at least one ridge (160, 160').

7. The polishing block (100) according to any of the preceding claims, wherein a gap (190) is provided under the at least one ridge (160, 160') in order to gain a certain resilience for enabling a position shift for the handle.

8. The polishing block (100) according to any of the preceding claims, wherein the polishing block (100) is made from injection moulded thermoplastic.

9. The polishing block (100) according to claim 9, wherein the thermoplastic is poly propene or poly propylene (PP).