The invention relates to a plaster knife. Such plaster knifes are used for finishing an already plastered surface such as a wall or wall surface in a house. After applying plasterwork on the surface, often using a trowel or float, the plasterwork has to be finished. Rough plasterwork is applied using a trowel or float. However, the surface should be aesthetically attractive. Accordingly, it will be finished using a plaster knife, which enables obtaining a smooth and regular surface after the plaster knife is moved over the rough surface. Because a knife side is moved over the rough surface, this results in a desired finishing of the surface. Moreover, the plaster knife can also generate a desired pattern. This may for example be a pattern of lines, wherein the knife side along its side is provided with a plurality of recesses. The plurality of recesses often have a regular pattern corresponding to the desired line pattern.

Handling the plaster knife is done manually by a user. The user picks up and holds the plaster knife by a handle and moves the plaster knife manually, in such a way that the knife side follows a desired movement resulting in a desired finish of the surface. By exerting force on the plaster knife the user is able to apply a pressure on the to be finish surface.

The disadvantage of existing plaster knifes is that when moving the plaster knife there is a risk that a hand of the user is in the plastered surface. This results in an ugly finish or at least additional work, because the ugly finish must be re-finished. It also results in dirty hands.

A further disadvantage is that current plaster knifes are ergonomically inconvenient. For a precise finish a constant and controlled movement of the hand of the user is required.

To obtain a smooth and regular surface, a uniform pressure on the surface of the knife side is necessary. This forces the user to manoeuvre his hand and arm in often cramped positions for creating a constant, smooth and controlled movement.

The object of the present invention is to provide a plaster knife, wherein these drawbacks are at least partially overcome, or to at least provide a useful alternative.

In particular, the aim of the invention to provide a user-friendly plaster knife.

According to the invention, this object is achieved by a plaster knife according to claim 1.

This plaster knife is suitable for finishing a plastered surface. With finishing is meant treating a rough plastered surface in a controlled manner to obtain a desired substantially smooth and regular surface. It is foreseen that the smooth surface can also comprise a pattern of lines.

The plaster knife comprises a blade-shaped knife which is provided with a

longitudinal side and an opposite knife side. The knife side is hereby suitable for a scraping over the plastered surface, such that a desired finish is obtained. The plaster knife further comprises an elongated holder which is disposed along the longitudinal side of the blade- shaped knife for the at least partial reinforcement of the longitudinal side of the blade- shaped knife. The strengthening of the longitudinal side of the blade-shaped knife results in that a user in a controlled way can transfer forces to the knife side.

The plaster knife further comprises an elongated handle which is arranged to the elongated holder. The user controls the plaster knife by exerting, with one hand, a force on the elongated handle. This force is transmitted via the elongated handle to the knife side, where the knife side can exert a corresponding pressure or force to a to be finished surface. The plaster knife is arranged in a first position in which a longitudinal axis of the elongated handle is situated perpendicularly with respect to the longitudinal side of the blade-shaped knife. This way the handle is perpendicular to the longitudinal side.

Preferably the elongated handle is provided in a middle of the longitudinal side. This has the advantage that in a symmetrical way forces can be exerted by the user to the knife side, such that in an easier way an equal pressure or force along the knife side can be passed on to the rough plastered surface.

The plaster knife comprises a hinge which is arranged between the elongated handle and the elongated holder for rotating the elongated handle with respect to the elongated holder to a second position. In the second position a rotational axis, being the axis about which the elongated handle is rotating, is perpendicularly situated with respect to the plane in which the blade-shaped knife is located.

The second position is preferably set by the user with the help of first adjusting means. The first adjusting means in a first adjustment position fix the handle in the first position or the second position. By bringing the adjustment means to a second adjustment position, the handle is free to rotate with respect to the elongated holder. This has the advantage that the second position can take on a user-selectable angular value. This allows for a more ergonomic handling and possibly tuned to the user.

The plaster knife further comprising a spacer disposed between the elongated handle and the elongated holder for keeping the elongated handle at a distance relative to the elongated holder. The elongated holder is spaced by the spacer from a plane in which the blade-shaped knife is located. The spacer is therefore located between a plane in which a longitudinal axis of the elongated handle is located and a plane in which a longitudinal axis of the elongated holder is located.

Due to the spacer being placed at a distance from the plane in which the blade- shaped knife is located, the chance that during use the hand of the user gets dirty and / or the work surface is disturbed is reduced considerably.

In addition, the spacer results in a space between the handle and the blade-shaped knife. The handle is hereby situated in a plane parallel with respect to the plane in which the blade-shaped knife is located. The space between these surfaces is suitable for at least partly receiving the hand. This has as further advantage that the handle can rotate with a larger usable range. There are therefore more second positions possible which increases the ergonomic possibilities. The hand of the user is less likely clamped between the handle and the blade-shaped knife due to the resulting space that has been created by the spacer. Moreover, because of the larger usable range, it is less necessary to bring wrists and / or elbow joints and/or shoulder joints in an end position during finishing. At least, the joints require to be rotated less close to an end position during use of the plaster knife while it is still possible to produce the same quality of finishing.

An additional advantage is that by rotating the handle in a desired position, and by the handle being on a distance relative to the blade-shaped knife a more ergonomic operation of the plaster knife during finishing is possible. A created space between the handle and the blade-shaped knife in a desired rotational position results in a lower load of a shoulder belt of the user. Because the handle can be rotated in more desired second positions a shoulder joint is brought in to less lower end positions during finishing.

In particular, the prevention of excessive rotations in shoulder joints is possible with the plaster knife according to the invention. In addition to a reduction of a load of shoulder joint and of elbow joints, also wrist joints can be burdened much less burden because the handle can move more in contrast to the conventional plaster knife. Also, a torsion movement about the longitudinal direction of the forearm of the user is much less necessary. At least it is less necessary that this torsional movement leads to end positions of the forearm. It is also apparent that flexion-rotation components in the lower back of the user occur less if the blade is brought into a desired rotation.

Preferably, the spacer is an elongated spacer having a longitudinal axis which is arranged perpendicular to the plane in which the blade-shaped knife is located and which coincides with the rotational axis for rotating the handle with respect to the holder. The rotational axis of the pivot joint is aligned with a longitudinal axis of the spacer, such that the axis of rotation imaginary crosses the plane in which the elongated blade is located.

This has the advantage that at least a portion of the handle is located above the holder so that a force can be transferred from the hand via the handle to the holder and thus the blade in a more controllable manner. This is the case because the handle is located more close to the knife side, and thereby smaller moments are generated.

In one embodiment according to the invention, the plaster knife further comprises a tilting hinge between the elongated handle and the elongated holder for the tilting of the elongated handle relative to the elongated holder to a second position, wherein a tilting axis is located in a plane parallel to the plane in which the blade-shaped knife is located. The tilting axis is thus located at a distance with respect to the plane in which the blade-shaped knife is located.

This has the advantage that more positions of the handle relative to the holder can be selected, wherein the hand of the user still has enough room to grip the handle.

In one embodiment according to the invention, a first end of the elongated handle is located at a distance with respect to the plane in which the blade-shaped knife is located when in the first position. The first end is located proximal in relation to the user when the user has fixed the handle. The tilting hinge is hereby arranged for tilting of the handle to the second position, wherein the first end moves away from the plane in which the blade-shaped knife is located.

This has the advantage that the first end of the blade moves away, and more space is created between the handle and the blade. Although the handle is being spaced with respect to the blade, the path that that the force travels from the hand of the user to the knife side remains relatively small, while the user does have the possibility to operate the plaster knife in in different tilted positions. This increases the usability.

In one embodiment according to the invention a first end of the elongated handle is located distally with respect to the blade-shaped knife when in the first position. The pivot hinge is arranged for rotating the elongated handle to the second position, such that the first end is located proximally with respect to the blade-shaped knife. With proximal it is meant that the first end is directed towards the blade-shaped knife. The handle is then rotated such that the first end is located above the holder or the blade-shaped knife. This has the advantage that it is possible for the user to operate the plaster knife in a more ergonomic way such that convulsive movements and unnatural rotations of the wrist joints, elbow joints and shoulder joints is reduced. When the user is holding the handle, while the first end is located proximally with respect to the user, the knife side is at least partly directed towards the user. This is in contrast to known plaster knifes. This makes it possible to, while maintaining a controlled operation of the plaster knife .finish with a more comfortable and user-friendly way the to be finished rough plastered surface.

In one embodiment according to the invention, the first end coincides with the knife side when in the second position viewed in a plane parallel to the plane in which the knife- shaped blade is located.

This is particularly advantageous because the transmission of force from the hand to the knife side is optimal. In use, a wrist of the user is located close the knife side which allows a better appliance of control on the plaster knife. In one embodiment according to the invention, the plaster knife further comprises adjustable displacement means between the spacer and the holder for the movement of the elongated handle relative to the elongated holder from a first position to a second position, parallel to the plane in which the blade-shaped knife is located .

This is advantageous because it enables the hard to reach surfaces to be finished accurately. The handle moves or translates relative to the knife-shaped blade. The degree of displacement can be adapted to a geometry of a surroundings of a to be plastered surface. For example, should the to be plastered surface be in a surroundings which blocks a free movement of the plaster knife, then the handle can be moved such that a blockade is avoided and the user still has sufficient control to finish the to be plastered surface.

With the adjustability of the displacement means it is meant that the displacement means are arranged for fixing of the handle in a fixed adjustment position, such that the handle is fixed in the first position or the second position. Also, the displacement means are arranged for a free movement of the handle in a free adjustment position. With free movement it is meant movement between the first position and the second position.

In one embodiment according to the invention, the adjustable displacement means are arranged for linearly displacing the elongated handle in a direction parallel to the longitudinal side of the elongated holder.

This has the further advantage that the elongated holder can be moved with a pre- determinable rectilinear movement relative to the blade-shaped knife. As a result, it is possible to change the position of the elongated holder relative to the blade-shaped knife with repeatable accuracy. This makes it possible to work accurately in small spaces.

In one embodiment according to the invention, the adjustable displacement means are arranged for linearly displacing the elongated handle in a direction perpendicular to the longitudinal side of the elongated holder.

This has the further advantage that the elongated holder can be moved with a pre- determinable rectilinear movement relative to the blade-shaped knife. As a result, it is possible to change the position of the elongated holder relative to the blade-shaped knife with repeatable accuracy. This makes it possible to work accurately in small spaces.

In one embodiment according to the invention, the knife side is rectilinear.

This has the advantage that smooth surfaces can be finished more easily.

In one embodiment according to the invention, the knife side is curvilinear.

This has the advantage that curved surfaces can be finished more easily.

In one embodiment according to the invention, the plaster knife further includes first adjustment means for adjusting a pivot position of the elongated handle relative to the elongated holder.

This makes it on the one hand possible to fix the handle in a first pivot position or a second pivot position, while both pivot positions are unequal with respect to each other, and on the other hand move freely between the first pivot position and the second pivot position.

In one embodiment according to the invention, the plaster knife further includes second adjusting means for adjusting a tilting position of the elongated handle relative to the elongated holder.

This makes it on the one hand possible to fix the handle in a first tilting position or a second tilting position, while both tilting positions are unequal with respect to each other, and on the other hand move freely between the first tilting position and the second tilting position.

In one embodiment according to the invention, a recess in the elongated handle is provided near a second end of the elongated handle for receiving at least a portion of a hand of a user, such that at least one adjustment means is operable by the portion of the hand, during the holding of the elongated handle.

This is advantageous because it allows a simple adjusting of the plaster knife, i.e. a simple adjusting of a tilting position, pivot position, the first position and / or the second position. The first position is composed of a first tilting position and a second pivot position. Depending on the embodiment of the plaster knife the first pivot position, and possibly the first tilting position, is adjustable to the second pivot position, and possibly the second tilting position, by respectively applying a first adjustment means and a second adjustment means.

In one embodiment according to the invention, a stabilizer is provided at a first end, wherein the stabilizer, when the handle is in a second position when the handle is parallel with the holder, comprises protrusion which engages in a groove provided in the holder.

The stabilizer is releasable connected to the handle for example by means of a click or a turn connection. The stabilizer can, by turning and/or tilting the handle, be moved from an initial position to an end position. The initial position can be any position. In the end position the stabilizer engages a slot, for example a rail which is already present for the movement of the handle. In the end position, the handle is, therefore, parallel and placed at a distance from the slot, wherein the first end can transfer forces via the stabilizer and the slot to the blade-shaped knife via the holder. The second end, transfers forces via the spacers to the blade-shaped knife.

This has as advantages that the plaster knife can be an additional extension of an arm. There is more reach in length and width such that a more easy reaching behind obstacles such as cables, pipes, etc. is possible. Moreover, the plaster knife is easy to handle for both left and right handed users. At the same time a better distribution of forces is possible which can result in a more clean finish. In an embodiment, the pivot hinge comprises a first rotating part and a second rotating part. The first rotating part comprising a ring of protrusions and the second rotating part comprising a ring of recesses for receiving the corresponding ring of protrusions. The recesses correspond to the protrusions such that the protrusions can be snugly received by the recesses. The handle is fixable with respect to the holder by receiving the protrusions in the recesses.

This allows a multitude of second positions of the handle with respect to the holder. The handle can be freely rotated with respect to the holder when the protrusions are not received in the recesses. For this purpose the ring of protrusion is spaced away from the ring of recesses such that the protrusions are not received in the recesses. It also allows for a very snugly fixing of the handle with respect to the holder. The more recesses and corresponding protrusions are arranged the little play there is between the handle and the holder in fixed position. This allows for a more controlled transfer of forces of the hand of the user to the blade-shaped knife when the user is operating the plaster knife.

In a further embodiment, a first adjustment means is configured to displace the first rotating part with respect to the second rotating part for bringing the pivot hinge from a first adjustment position which fixes the handle with respect to the holder to a second adjustment position which allows the handle to rotate freely with respect to the holder and vice versa.

The first adjustment means may be a spring that can be operated by a finger of the user to move the first rotating part with respect to the second rotating part.

For example, in the first adjustment position the handle is fixed with respect to the holder which corresponds in that the first rotating part having protrusions is moved towards the second rotating part having recesses. The first rotating part is moved towards the second rotating part such that the protrusions are engaged in and received by the corresponding recesses, resulting in a fixing of the handle with respect to the holder.

For example, in a second adjustment position, the first rotating part is moved away from the second rotating part allowing the handle to rotate freely with respect to the holder. Now, the protrusions are moved out of the recesses.

In an even further embodiment, at least one of the rotating parts of the pivot hinge is provided with a seal.

This has as advantage that the risk of having the protrusions or recesses covered by filth and/or water is reduced.

In an even further embodiment, the recesses of the ring of recesses are slanted. The recesses are slanted with respect to an axis coinciding with a direction of movement of the first and second rotating parts when brought from a first adjustment position to a second adjustment position and vice versa.

Having slanted recesses, preferably on an outer side of the second rotating part, allows for even less play when the first rotating part is moved towards the second rotating part and the pivot hinge is brought into the first adjustment position, being the fixed position.

In an embodiment according to the invention, a reinforcement plate is arranged between the spacer and the elongated holder. The plane in which the reinforcement plate is located is parallel with respect to the plane in which the elongated holder is located.

This has as advantage that the plaster knife is strengthened further allowing an even more controlled finishing of the plastered surface. The invention also relates to a method for adjusting a second position of an elongated handle of a plaster knife according to the invention. This method includes the steps of adjusting the elongated handle relative to the elongated holder and finishing a plastered surface by means of the plaster knife.

The elongated handle is movable from a first position to the second position. In the first position and the second position the elongated handle is fixed with respect to the holder and the blade-shaped knife. With the aid of adjustment means, the elongated handle can move freely between the first position and the second position, so that the elongated handle can be placed in a user desired first position or second position. This increases the ease of use for the user.

After the elongated handle is brought to the desired second position, the elongated handle can be fixed in the desired second position by means of the adjustment means. Subsequently, the user can finish a rough plastered surface using the plaster knife.

In one embodiment of the method according to the invention, adjusting comprises the tilting and rotation of the handle relative to the holder, in such a way that the handle is located above the blade-shaped knife.

This has the advantage that a position of the handle relative to the blade-shaped knife is obtained that is more user-friendly. Not only it is possible to operate the plaster knife with a stretched arm and wrist wherein the knife side is facing away from the user, but also the knife side which is turned towards the user. This allows a movement that is more ergonomic because you can make a scraping motion by means of less unnatural wrist-, shoulder- and elbow movements.

In one embodiment of the method according to the invention, adjusting comprises the movement of the handle relative to the holder.

This has the advantage that a displacement of the handle results in a geometry of the plaster knife that is suitable for less accessible surfaces for plastering.

Further preferred embodiments of the invention are defined in the sub-claims.

An embodiments of the invention will be further elucidated with reference to the accompanying drawings, in which:

figure 1 is a perspective view of a first embodiment of a plaster knife according to the invention, wherein an elongated handle is in a first position;

figure 2a shows a top plan view of the first embodiment of the plaster knife, in which the elongated handle is in the first position;

figure 2b shows a top plan view of the first embodiment of the plaster knife, in which the elongated handle is in a second position, rotated relative to the first position;

figure 2c shows a top plan view of the first embodiment of the plaster knife, in which the elongated handle is in an alternate second position, rotated relative to the first position; figure 3a shows a side view of the first embodiment of the plaster knife shows, in which the elongated handle is in the first position;

figure 3b shows a side view of the first embodiment of the plaster knife, in which the elongated handle is in an alternate second position, rotated relative to the first position; figure 4a shows a side view of a second embodiment of the plaster knife according to the invention, wherein an elongated handle is in a second position, tilted with respect to a first position;

figure 4b shows a side view of the second embodiment of the plaster knife, in which the elongated handle is in an alternate second position, tilted with respect to the first position;

figure 4c shows a side view of the second embodiment of the plaster knife, in which the elongated handle is in a further alternative second position, tilted with respect to the first position;

figure 5 shows a perspective view of the second embodiment of the plaster knife according to the invention;

figure 6 shows a perspective view of a third embodiment of a plaster knife according to the invention;

figure 7 shows a perspective view of a fourth embodiment of a plaster knife according to the invention;

figure 8 shows a perspective view of fifth embodiment of a plaster knife according to the invention, and

figure 9 shows a rear view of a sixth embodiment of a plaster knife according to the invention;

figure 10 shows a perspective view of a pivot hinge of a seventh embodiment of a plaster knife according to the invention;

figure 1 1 a, 1 1 b and 1 1 c show respectively a top view, side view and bottom view of a pivot hinge of the seventh embodiment;

figure 12a and 12b show a perspective views of a pivot hinge according to the seventh embodiment;

figure 13a and 13b show respectively a perspective view and a side view of a pivot hinge according to the seventh embodiment;

figure 14a and 14b show respectively a perspective view and a side view of an eight embodiment of a plaster knife according to the invention. In fig. 1 , a first embodiment of a plaster knife 1 according to the invention is shown and is indicated in its entirety by the reference numeral 1. The plaster knife 1 is suitable for finishing of a plastered surface. This is fundamentally different from the applying of plasterwork on a plastered surface using for example a trowel or a float. After applying plasterwork a rough plastered surface is acquired, wherein the trowel or float do not necessarily need to operate accurately in comparison with a plaster knife 1.

Not only the goal is different, but the applying of plasterwork also requires a different ergonomic movement compared to finishing. With finishing is understood that the acquiring of a regular and smooth surface by means of the plaster knife 1. For this purpose the plaster knife 1 is provided with a blade-shaped knife 3. The blade-shaped knife 3 comprises a longitudinal side 5 and an opposite knife side 7. The knife side 7 is relatively sharp so that it is easier to obtain a smooth and regular surface.

To achieve a correct movement of the plaster knife 1 with respect to a to be plastered surface, the plaster knife 1 further comprises an elongated holder 9. The elongated holder 9 is arranged along the longitudinal side 5 of the blade-shaped knife 3 for the at least partial reinforcement of the longitudinal side 5 of the blade-shaped knife 3. Here, the elongated holder 9 is arranged along the entire longitudinal edge 5 of the blade-shaped knife 3. The elongated holder 9 ensures a consolidation of the blade-like blade 3 and increases the rigidity of the blade-shaped knife 3. This has as positive consequence that a force exerted by a user on the blade-like blade 3 is transferred, in a controlled manner, to the to be finished surface.

Without the elongated holder 9, the blade-shaped knife 3 is too much flexible and the user has little control to obtain a to be finished surface that is sufficiently smooth and regular.

The plaster knife 1 further comprises an elongated handle 1 1 that is arranged to the elongated holder 9. The user can operate the plaster knife 1 by grabbing the elongated handle 1 1 with his hand. As a result, a force, exerted by the hands of the user , is ultimately transmitted through the knife side 7 on the rough plastered surface that is to be finished.

Often, a repetitive motion of the hand is needed, so that the joints of the user, such as wrist joints, shoulder joints, elbow joints must repeatedly be moved in certain positions. Due to the predetermined geometry of conventional plaster knifes this is often felt as not as comfortable.

The elongated handle 1 1 is located in this figure in a first position in which a longitudinal axis of the elongated handle 1 1 is situated perpendicularly with respect to the longitudinal side 5 of the blade-shaped knife 3. This is a position that is known in

conventional plaster knifes.

As also shown in figures 2a, 2b and 2c the elongated handle 1 1 comprises further a pivot hinge 15 which is disposed between the elongated handle 1 1 and the elongated holder 9 for rotating the elongated handle 1 1 relative to the elongated holder 9 to a second position. As can be seen, the axis of rotation of the pivot hinge 15 is located at right angles with respect to the plane in which the blade-shaped knife 3 is located.

In figure 2a, the elongated handle 1 1 is shown in the first position, which corresponds to the first position as shown in Figure 1. In Figures 2b and 2c two different second positions can be seen, in which the elongated handle 1 1 is pivoted or rotated relative to the first position. It should be noted that any arbitrary position with a second angle relative to the first position is intended and foreseen. Figures 2b and 2c show only a few examples.

The plaster knife further comprises a spacer 14a, 14b disposed between the elongated handle 1 1 and the elongated holder 9 for keeping the elongated handle 1 1 at a distance from the elongated holder 9 and at a distance from a plane in which the blade- shaped knife 3 is located.

The spacer 14a, 14b is located between a plane in which a longitudinal axis of the elongated handle 1 1 is located and a plane in which a longitudinal axis of the elongated holder 9 is located.

Here, the plaster knife comprises a first spacer 14a and a second spacer 14b, which together form the spacer 14a, 14b and together provide for keeping the elongated handle 1 1 at a distance with respect to the elongated holder 9 and the blade-shaped knife 3.

In alternative embodiments, the spacer 14a, 14b is also integrally formed from one part or is formed from more than two parts.

Due to the elongated handle 1 1 being placed at a distance from the elongated holder

9 and the blade-shaped knife 3, it is possible for the elongated handle 1 1 to be rotated above the blade-shaped knife 3.

The spacer 14a, 14b is an elongated spacer having a longitudinal axis which is arranged perpendicular to the plane in which the blade-shaped knife 3 is located and which coincides with the rotational axis Y1 , Y2 for rotating the handle 1 1 with respect to the holder

9.

A distance between on the one hand, the elongated handle 1 1 and on the other hand the elongated blade-shaped holder 9 and the blade-shaped knife 3 is preferably chosen sufficiently large such that a hand of the user has enough space to grip or hold the elongated handle 1 1. Fingers of the user may then fit in the space. Advantages of spacing the elongated handle 1 1 is that it make more ergonomic movements possible which still lead to the same result of finishing. Depending on the wishes of the user, the elongated handle 1 1 can be rotated with respect to the blade-shaped knife 3.

In the first position of the elongated handle 1 1 , mainly, the wrist joint is rotated when the user operates the plaster knife 1 in a conventional manner.

When the elongated handle 1 1 is in a second position as shown in figure 2b, mainly, the shoulder joint can be rotated and the wrist joint can be relieved more.

When the elongated handle 1 1 is in a second position as shown in figure 2c, mainly, the shoulder joint and the elbow joint can be rotated and the wrist joint can also be relieved more.

Rotating the elongated handle 1 1 and spacing of the elongated handle 1 1 therefore results in an adjustable load distribution on respectively the wrist-, elbow- and shoulder joints.

It thus allows the prevention of a unilateral loading of the wrist joint by allowing more use of the elbow joint and/or shoulder joint, while still allowing precise operation by the user such that the finishing accuracy still maintains it accuracy.

A further advantage is that the hand of the user is not only at a distance from the blade-shaped knife 3, during use, but also at a distance from the surface to be finished. This has the additional result that the risk of dirty hands or disrupting a smooth and regular surface is greatly reduced, due to the hand coming less into contact with the finished surface.

Figure 3a shows a side view of the plaster knife 1 in which the elongated handle 1 1 is in the first position. In figure 3b, the elongated handle 1 1 is rotated to an alternative second position.

In the first position a first end 12a of the elongated handle 1 1 is distally located with respect to the blade-shaped knife 3. The pivot hinge 15 is arranged for rotating the elongated handle 1 1 to the alternative second position shown in figure 3b, such that the first end 12a is located proximal relative to the blade-shaped knife 3.

Here the first end 12a, being in the second position, is located above the blade- shaped knife 3 and the first end 12a, being in the first position, is not located non above the blade-shaped knife 3. In this second position, it is possible for the user to do the finishing, wherein mainly the elbow joints are rotated when a back-and-forth movement of the plaster knife 1 is started. This is more ergonomic and less burdensome as compared to essentially rotating the wrist joints, which is the case when the elongated handle 1 1 is in the first position.

In the second position shown in figure 3b, the first end 12a is aligned with the knife side 7 viewed in a plane parallel to the plane in which the blade-shaped knife 3 is located.

This is a particularly advantageous second position, since this allows an optimum distribution of loads between the wrist joints, elbow joints and shoulder joints. All three joints are evenly loaded when the user operates the plaster knife 1 during finishing. Figures 4a, 4b and 4c show side views of a second embodiment of a plaster knife

201 according to the invention.

The second embodiment is for a large part similar to the first embodiment, wherein features having similar reference signs relate to the same features. For example, the blade- shaped knife 3, the elongated holder 9, and the elongated handle 1 1 are the same.

In the second embodiment of the plaster knife 201 , the plaster knife 201 is further provided with a tilting hinge 25 between the elongated handle 1 1 and the elongated holder 9 for tilting the elongated handle 1 1 with respect to the elongated holder 9 to a second position, wherein a tilting axis Z1 is located in a plane parallel to the plane in which the blade-shaped knife 3 is located. The tilting axis Z1 is shown in figure 2c.

The tilting hinge 25 in this embodiment is located between the first spacer 14a and the second spacer 14b. The corresponding first rotational axis Y1 of the rotating hinge 15 is indicated with dotted line Y1.

In an alternative, the pivot hinge 15 can be arranged in the second spacer 14b. The corresponding second rotational axis Y2 of such a pivot hinge 15 is indicated with dotted line Y2.

In figures 4a, 4b and 4c the tilting axis Z1 is arranged perpendicular with respect to the plane of the figure. This way, the elongated handle 1 1 can also be tilted to different second positions as indicated in the figures.

For example, figure 4a shows a tilting position wherein the first end 12a is arranged above the blade-shaped knife 3.

For example, figure 4b shows a tilting position wherein the first end 12a is arranged below the blade-shaped knife 3.

Finally, figure 4c shows a tilting position which is similar to the tilting position shown in figure 4a, however wherein the elongated handle 1 1 is rotated with 180 degrees with respect to the second position as shown in figure 4a. All three shown second positions in figures 4a, 4b and 4c allow a certain operation of the plaster knife 201 of which each results in a certain distribution of loads on the wrist joints, elbow joints and shoulder joints. Depending on the desire of the user, but also on the surroundings of the to be finished surface, a certain second position can be chosen.

As shown in figure 4a, the first end 12a of the elongated handle 1 1 , when in the first position, is spaced with respect to the plane in which the blade-shaped knife 3 is located. The tilting hinge 25 is arranged for tilting the elongated handle 1 1 to the second position, wherein the first end 12a moves away from the plane in which the blade-shaped knife 3 is located.

For further elucidation, figure 5 shows a plaster knife 201 according to the second embodiment, wherein the plaster knife 201 comprises a pivoting hinge 15 as well as a tilting hinge 25, which are arranged between the elongated handle 1 1 and the blade-shaped knife 3. Figure 5 also shows the longitudinal axis X1 of the elongated handle 1 1.

In particular, the pivot hinge 15 provides a range of rotation of 360 degrees.

In the first position, the elongated handle 1 1 is arranged parallel with respect to the blade-shaped knife 3. In particular, the tilting hinge 25 provides a tilting range between -90 and 90 degrees with respect to the first position. Further in particular, the tilting range is between -70 and 70 degrees. Even further in particular, the tilting range is between -45 and 45 degrees.

Figure 6 shows a third embodiment according of a plaster knife 301 provided with a blade-shaped knife 303 according to the invention. Here, this third embodiment is similar to the first- and/or second embodiment, however the knife side 307 is curvilinear. The knife side 307 is curved convex such that it is suitable to finish a concave surface (not shown). With this it is meant that the knife side 307 is curved convexly and suitable to finish a concave surface. The knife side 307 is therefore curvilinear. The knife side 307 is curved such that it can be received substantially fitted in a concave surface for finishing this surface. For this purpose, the knife side 307 is curved more convex than the concave surface is curved.

This has as advantage that the plaster knife 301 is suited for an accurate finishing of a plastered curved surface, wherein the advantages of a tilting and/or pivoting handle 1 1 are present.

Figure 7 shows a fourth embodiment of a plaster knife 401 according to the invention. It is foreseen that this embodiment is similar to the first- and/or second- and/or third embodiment, however the elongated handle 41 1 comprises, near a second end 12b, a recess provided in the elongated handle 41 1. This recess is suitable for receiving at least a part of a hand of a user, such that at least one adjustment means is adjustable by the part of the hand, during holding of the elongated handle 411.

Figure 8 shows a fifth embodiment of a plaster knife 501 according to the invention. Here, this embodiment is similar to the first- and/or second- and/or third- and/or fourth embodiment, however this plaster knife 501 comprises adjustable displacement means between the spacer 14a, 14b and the elongated holder 9 for displacing the elongated handle 11 with respect to the elongated holder 9 form a first position to a second position, parallel to the plane in which the blade-shaped knife 3 is located.

In this embodiment the adjustable displacement means are arranged for linearly displacing the elongated handle 1 1 in a direction parallel to the longitudinal side of the elongated holder 9. In figure 8, this is a linear displacement in the direction indicated by arrows A and B. A rail 35 is provided to the spacer 14a, 14b for linear displacing the handle 1 1.

It is also possible to arrange the adjustable displacement means for linear displacing the elongated handle 1 1 in a direction perpendicular to the longitudinal side of the elongated holder 9. In figure 8 this is a linear displacing indicated with the arrows C and D.

For all embodiments disclosed in the figures it is foreseen that these are arranged with first adjustment means 16 for adjusting a rotating position of the elongated handle 1 1 with respect to the elongated holder 9.

The first adjustment means 16 for example is a push button in two adjustment positions. In a first adjustment position the rotational position is fixed. In a second

adjustment position the elongated handle 1 1 is freely rotatable until a desired second position of the elongated handle 1 1 is reached. Subsequently, the first adjustment means 16 is operated and the elongated handle 1 1 is fixed with respect to rotating.

For the embodiments with a tilting hinge it is foreseen that they are provided with second adjustment means 26 for adjusting a tilting position of the elongated handle 11 with respect to the elongated holder 9.

The second adjustment means 26 is a lever which can be moved in two adjustment positions. In a first adjustment position the tilting position is fixed. In a second adjustment position the elongated handle 1 1 is freely tiltable as long as until a desired second tilting position is reached. Subsequently, the second adjustment means 26 is operated again and the handle 1 1 is fixed with respect to tilting.

Figure 9 shows a stabilizer 40 arranged in a plaster knife 501 according to a sixth embodiment. Here it is foreseen that this embodiment is similar to the fifth embodiment, however the plaster knife 501 further comprises a stabilizer 40 which is arranged to the first end 12a of the elongated handle 41 1. The stabilizer 40 is releasable arranged to the first end 12a of the elongated handle 41 1 by means of for example a click or turn connection. Here, the stabilizer 40 is arranged to the elongated handle 41 1 by means of a turn connection. The stabilizer 40 can be moved from an initial position to an end position by rotating and/or tilting the handle 41 1. The initial position can be any arbitrary position. In the end position the stabilizer 40 engages in the rail 35. In the end position the handle 1 1 is therefore located parallel and spaced with respect to the rail 35, wherein the first end 12a can transfer forces via the stabilizer 40 and the rail on blade-shaped knife 7 via the holder 9. The second end 12b transfers forces, via the spacers, on the blade-shaped knife 7. The advantages is that the plaster knife is an additional extension of an arm. More reach in terms of length and width is available such that reaching behind obstacles, such as cables, pipes, etc. is possible. Moreover, it allows the plaster knife to be operated easily by left handed users as well as right handed users. At the same time, a better force distribution is possible which may result in a finishing that is more clean.

Figure 10 shows an elongated handle 71 1 comprised in a seventh embodiment of a plaster knife 701 according to the invention.

It is foreseen that this embodiment is similar to the first- and/or second- and/or third and/or fourth and/or fifth and/or sixth embodiment, however the elongated handle 711 comprises, near first end 12b, a first rotating part 720a of a pivot hinge 715.

Figure 10 shows the elongated handle 71 1 and the pivot hinge 715. The pivot hinge 715 comprises a first rotating part 720a and a second rotating part 720b. The first rotating part 720a comprises a ring of protrusions 730a and the second rotating part 720b comprising a ring of recesses 730b for receiving the corresponding ring of protrusions 730a. The recesses 730b correspond to the protrusions 730a such that the protrusions 730a can be snugly received by the recesses 730b. The handle 71 1 is fixable with respect to the holder 9 by receiving the protrusions 730a in the recesses 730b.

This allows a multitude of second positions of the handle 71 1 with respect to the holder 9. The handle 71 1 can be freely rotated with respect to the holder 9 when the protrusions 730a are not received in the recesses 730b. For this purpose the ring of protrusion 730a is spaced away from the ring of recesses 730b such that the protrusions 730a are not received in the recesses 730b.

It also allows for a very snugly fixing of the handle 71 1 with respect to the holder 9. Figure 1 1 a, 11 b and 11 c show the first rotating part 720a and the ring of protrusions 730a. Figures 12a and 12b show the second rotating part 720b and ring of recesses 730b. The second rotating part 720b is a cylinder with on one end arranged the ring of recesses 730b.

The more recesses 730b and corresponding protrusions 730a are arranged the little play there is between the handle 71 1 and the holder 9 in fixed position. This allows for a more controlled transfer of forces of the hand of the user to the blade-shaped knife 3 when the user is operating the plaster knife 701.

Furthermore, first adjustment means are configured to displace the first rotating part 720a with respect to the second rotating part 720b for bringing the pivot hinge 715 from a first adjustment position which fixes the handle 71 1 with respect to the holder 9 to a second adjustment position which allows the handle 71 1 to rotate freely with respect to the holder 9 and vice versa.

The first adjustment means may be a spring that can be operated by a finger of the user to move the first rotating part 720a with respect to the second rotating part 720b.

For example, in the first adjustment position the handle 71 1 is fixed with respect to the holder 9 which corresponds in that the first rotating part 720a having protrusions 730a is moved towards the second rotating part 720b having recesses 730b. The first rotating part 720a is moved towards the second rotating part 720b such that the protrusions 730a are engaged in and received by the corresponding recesses 730b, resulting in a fixing of the handle 71 1 with respect to the holder 9.

For example, in a second adjustment position, the first rotating part 720a is moved away from the second rotating part 720b allowing the handle 71 1 to rotate freely with respect to the holder 9. Now, the protrusions 730a are moved out of the recesses 730b.

In an even further embodiment, at least one of the rotating parts 720a, 720b of the pivot hinge 715 is provided with a seal (not shown).

This has as advantage that the risk of having the protrusions 730a or recesses 730b covered by filth and/or water is reduced.

In an even further embodiment, the recesses 730b of the ring of recesses 730b are slanted. This can be seen in figures 13a and 13b. The recesses 730b are slanted with respect to an axis W1 coinciding with a direction of movement of the first and second rotating parts 720a, 720b when brought from a first adjustment position to a second adjustment position and vice versa.

Having slanted recesses 730b, preferably on an outer side of the second rotating part 720b, allows for even less play when the first rotating part 720a is moved towards the second rotating part 720b and the pivot hinge 715 is brought into the first adjustment position, being the fixed position. In an eight embodiment according to the invention, a reinforcement plate 875 is arranged between the spacer 14a, 14b and the elongated holder 9 as can be seen in figures 14a and 14b. The plane in which the reinforcement plate 875 is located is parallel with respect to the plane in which the elongated holder 9 is located.

This has as advantage that the plaster knife is strengthened further allowing an even more controlled finishing of the plastered surface.

Besides the shown embodiments many variants are possible. For example, it is foreseen that all embodiments can be combined with each other depending on the desired corresponding advantages.

Thus, a plaster knife is provided which is more user friendly, wherein hands of a user are not getting dirty and is more ergonomic when in use. With more ergonomic is meant that operation is less burdensome for the user while a same accuracy of finishing is possible.