Narrow spatula handle and narrow spatula with such a handle

Description

[0001] The invention relates to a coating knife handle.

[0002] Classic putty knives have a cylindrical handle attached to a blade approximately perpendicular to the free edge of the blade. In this case, the handle is grasped "full-handed," meaning the fingers and thumb wrap around the handle in opposition.

[0003] Then the blade is applied forcefully against a surface to apply and smooth the coating. The blade must have sufficient flexibility to bend to apply the coating without scraping it from the face and sufficient rigidity so that the coating is pressed against the surface.

[0004] With this type of coating knife, the user can hold the handle very firmly without fatigue, but the application of the coating is not uniform across the entire width of the blade, especially if the blade is very wide (over 25 cm).

[0005] An improvement is to fix a handle parallel to the blade.

[0006] In this case, the plastering knife is gripped by pinching the handle between the fingers. For example, document FR2327374 describes such a plastering knife.

[0007] This type of handle has the advantage of allowing the handle to be manufactured with a profile that can be cut to the desired length. This allows for the manufacture of wide plastering knives, which allows for faster and more even work, as the application force is transmitted across the entire width of the blade.

[0008] However, the plastering knife in document FR2327374 is very impractical, because all the compressive force to be transmitted to the plaster is generated by pinching the handle between the fingers of the hand, which makes the operation painful and tiring. To avoid this, this document illustrates a position in which the handle is held in the palm of the hand, but this position requires the wrist to be bent sharply when applying the plaster, which causes pain when used.

[0009] Documents DE1845335, EP2137364 and EP3263801 propose a significant improvement to the plastering knife of the previous document, by providing a handle equipped with a gripping part and a lever part.

[0010] Although these handles gave satisfaction for a long time, we noticed that their grip was still not entirely satisfactory during use.

[0011] Thus, the handle of document DE1845335 slips very easily from the fingers, which must be pinched very tightly to hope to be able to pull the plastering knife during application.

[0012] Furthermore, the handle of documents and EP3263801 and EP2137364, which is illustrated in figure 1 , also forces the user to pinch the handle A tightly with the fingertips B, with the thumb C in hyper extension, which is tiring and uncomfortable.

[0013] Furthermore, in addition to the fingers pinching the handle, they tire quickly, because they are the ones that also apply the full twisting force to apply the coating, even if the rear end D of the handle gets stuck in the hollow E of the thumb.

[0014] Thus, as the device is used, the hand tends to stiffen and the user must stop working to rest.

[0015] Furthermore, this type of very rigid handle requires a hand position very close to the surface, forcing the user to significantly break the alignment between his hand and his forearm at the wrist. The alternative is to provide a very flexible blade, but this is to the detriment of the quality of application of the product.

[0016] In the long term, this type of handle causes musculoskeletal problems in both the fingers and the wrist.

[0017] The objective of the present invention is therefore to propose an economical handle, that is to say one which can be easily manufactured in the form of a profile, which is light and which limits user fatigue, while ensuring optimal application of the coating.

[0018] To achieve this, the invention provides a gripping part that allows the advantages of powerful gripping of the cylindrical handles and uniform application of the profiled handles to be combined, while preventing the hand from stiffening during application.

[0019] The invention more specifically relates to a coating knife handle consisting of a profile extending along a longitudinal direction and comprising a gripping part connected by a central part to a fixing part of an edge of a coating blade, in which the gripping part has a convex upper face intended to receive the palm and fingers of the user's hand. The convex curved upper face is connected to the central part, on the one hand: by a gripping area comprising a curved convex front gripping face, against which the user's fingers can bend, and directly connected to a curved concave gripping face located at the front of the central part, and on the other hand, by a lever area comprising a convex lower lever face located under the convex upper face, against which the user's thumb can bend in the direction of the articulation, and connected by a turning-back area to a concave support face located at the rear of the central part, the turning-back area providing a hollow allowing the end of the thumb to be housed by bending the thumb in the direction of the articulation.

[0020] By allowing the thumb to close in the direction of the joint instead of being in hyperextension as in the prior art, the cusp zone of the handle according to the invention allows a natural stiffening of the user's wrist, which transfers the application force to the arm and therefore to the shoulder, which is much more resistant to fatigue.

[0021] According to particular embodiments: the convex upper face may have a main radius of curvature of between 9 and 11 cm, preferably 10 cm; the convex lower lever face may have a radius of curvature of between 7 and 9 cm, preferably 8 cm; the curved convex front grip face and the curved concave grip face may have a radius of curvature of between 0.8 and 1.2 cm; the concave support face may have a radius of curvature of between 2.4 and 2.8 cm, preferably 2.6 cm; the cusp zone may have a curved convex cusp face having a radius of curvature of between 0.2 and 0.6 cm, preferably 0.4 cm; the convex upper face may be connected to the convex lower lever face by a curved convex support face having a radius of curvature of between 0.6 and 0.9 cm, preferably 0.75 cm;cross-sectional view of the handle, the gripping part may have a median plane, passing through a middle of the curved convex front grip face and a middle of the curved convex rear support face, the median plane forming an angle (α) with the reference plane;and / or the fixing part may be extended by a compression part intended to bear against the deformable coating blade when the latter is fixed to the coating knife handle, the compression part comprising a first flat bearing surface extending in a reference plane on one side of which the compression part is located and on the other side of which the blade is located when the latter is fixed to the coating knife handle, and in which the fixing part further has a fixing heel intersecting with the reference plane and comprising a second flat surface for fixing the blade, the first and second flat surfaces forming an open angle between them, less than 179.9°, preferably less than 179.5°, advantageously between 177 and 179.5°. ;

[0022] The invention also relates to a plastering knife comprising a previous plastering knife handle, and a constrained flat blade fixed in force against the second flat fixing surface carried by the heel, and pressed in force against the first flat bearing surface of the compression part.

[0023] The invention also relates to an assembly comprising a preceding handle and a part for fixing an extension handle to this handle, the fixing part having a shape complementary to the grip and lever zones of the handle to be able to be secured to the handle.

[0024] The preceding assembly may also include an extension handle provided with said fixing part.

[0025] Other characteristics of the invention will be set out in the detailed description below given with reference to the appended figures, given by way of example, and which represent, respectively: [ Fig. 1 ], a schematic side view of a prior art coating knife handle and showing the pinched hand position with the fingertips; [ Fig. 2 ], a schematic side view of a coating knife handle according to the invention and showing the position of the hand in an embrace with the whole of a hand; [ Fig. 3 ], a schematic perspective view of the handle of the figure 2 [ Fig. 4 ], a schematic sectional view of the handle of the figure 2 illustrating the radii of curvature of the handle according to the invention; [ Fig. 5 ], a schematic sectional view of the handle of the figure 2 illustrating the dimensions and proportions of the handle according to the invention; [ Fig. 6 ], a schematic sectional view of the handle of the figure 2 illustrating the inclination of the gripping portion relative to the blade attachment portion of the handle according to the invention; [ Fig. 7 ], a schematic side view of a coating knife handle according to the invention and showing a first embodiment, in enlargement, of the cusp zone; [ Fig. 8 ], a schematic side view of a coating knife handle according to the invention and showing a second embodiment, in enlargement, of the cusp zone; and [Fig. 9], a schematic sectional view of a partial enlargement IX of the handle of the figure 2 illustrating the blade attachment heel.

[0026] By convention, in the remainder of this description, the so-called “upper” elements are those located towards the top of the handle of the figure 2 , the so-called “front” or “distal” elements are those located to the right of the handle of the figure 2 , that is to say towards the blade and away from the user, the so-called "rear" or "proximal" elements are those located towards the left of the handle of the figure 2 , that is, opposite the blade and towards the user, and the so-called "lower" elements are those located towards the bottom of the handle of the figure 2 .

[0027] Also by convention, we understand by "curve" a surface formed by an arc of a circle.

[0028] In reference to the figures 2 à 6 , a coating knife handle 100 according to the present invention comprises a profile extending along a longitudinal direction L (see figure 3 ). The handle 100 comprises, seen in profile, a gripping part 110 connected by a central part 120 to a fixing part 130 of an edge of a blade to be coated 200. In other words, the handle is fixed to the blade in a manner substantially parallel to the free edge of the blade.

[0029] The shape of the gripping portion 110 and the central portion 120 allows the user to grasp the handle in a grip, that is to say with the whole hand with the fingers and thumb bent in the direction of the joints. This effect is obtained by the gripping portion 110 which has a convex curved upper face 111 intended to receive the palm and the fingers of the user's hand, and which is connected to the central portion 120 by a distal gripping zone 112 and by a proximal lever zone 113.

[0030] The distal gripping area 112 includes a curved convex front gripping face 114, against which the user's fingertips can bend, allowing the user to pull the plastering knife during use.

[0031] The front grip convex curved face 114 is directly connected to a concave curved face 121 located in front of the central portion 120.

[0032] Towards the rear, the convex upper face 111 is also connected to the central part by the lever area 113 which comprises a convex lower lever face 115 located under the convex upper face 111 in the position illustrated in figure 2 , and against which the user's thumb can be pressed to allow the user to perform a lever movement with his thumb.

[0033] Advantageously, the convex curved upper face 111 is connected to the convex curved lower lever face 113 by a convex curved support face 116.

[0034] The convex lower face of lever 115 is connected to a concave support face 122 located at the rear of the central part 120 by a cusp zone 117.

[0035] Thanks to this 117 cusp zone, the user can come and wedge the C1 end of his thumb C by bending the latter in the direction of the C2 joint and not in hyper extension as in l'état of the technique. This position allows the hand to embrace the gripping part in a very powerful and comfortable position.

[0036] Furthermore, this grip position is very effective since it is the powerful muscles of the forearm that squeeze the handle, whereas in pinching between the fingertips, it is the much less powerful muscles of the hand that squeeze the handle.

[0037] In addition to the specific shapes (concave, convex, curved, and cusp zone), the grip's support and comfort are particularly optimized for specific dimensions.

[0038] In an advantageous embodiment, the convex upper face 111 has a main radius of curvature R1 of between 9 and 11 cm, preferably 10 cm, and an arc length L1 of between 5.2 cm and 5.7 cm, preferably 5.5 cm. These dimensions allow the palm of the hand to be completely pressed against the convex upper face 111 and facilitate the placement of the tips of the fingers and the thumb.

[0039] Likewise, the convex lower face of the lever preferably has a radius of curvature R2 of between 7 and 9 cm, advantageously 8 cm, and an arc length L2 of between 2 cm and 3 cm, preferably 2.5 cm.

[0040] The convex curved support face 116 having a radius of curvature R7 of between 0.6 and 0.9 cm, preferably 0.75 cm and an arc length L7 of between 2 cm and 2.2 cm, preferably 2.1 cm.

[0041] Towards the front, the curved convex front grip face 113 and the curved concave grip face 121 have a radius of curvature R3-R4 of between 0.8 and 1.2 cm, advantageously 1 cm, provided that the radius of curvature R3 of the curved convex front grip face 113 is strictly greater by at least 0.2 cm than the radius of curvature R7 of the curved convex support face 116.

[0042] The radii of curvature R3 and R4 may be the same. However, the radius of curvature R3 of the convex curved face 114 may be slightly larger to smooth the transition with the convex upper face 111. For example, the radius of curvature R3 of the convex curved face 114 may be 1.2 cm when the radius of curvature R4 of the concave gripping curved face 121 is 1 cm.

[0043] The front convex curved grip face 113 and the concave curved grip face 121 have respective arc lengths L3 and L4 of between 2.5 and 3.2 cm. They may be the same or different if the radius of curvature R3 of the convex curved face 114 is slightly larger than the radius of curvature R4 of the concave curved grip face 121.

[0044] Their respective lengths L3 and L4 can be different, which allows an inclination of the gripping part relative to the horizontal and improves user comfort, as described below.

[0045] In the previous example, if the radius of curvature R3 of the convex curved face 114 is 1.2 cm and the radius of curvature R4 of the concave curved grip face 121 is 1 cm, then the arc length L3 of the convex curved face 114 may be 3 cm and the arc length L4 of the concave curved grip face 121 may be 2.8 cm.

[0046] In doing so, the gripping portion 110 allows a powerful grip of the hand which completely embraces this gripping portion, all the fingers being bent in the direction of the joints without being in hyperextension.

[0047] Also preferably, the concave bearing face 122 has a radius of curvature R5 of between 2.4 and 2.8 cm, preferably 2.6 cm, and an arc length L5 of between 2.2 and 2.6, preferably 2.4 cm.

[0048] In a preferred embodiment illustrated in figure 6 , the radii, the lengths and the orientations of the different faces are chosen so that, seen in cross-section of the handle, the gripping part 110 has a median plane P1, passing through a middle of the curved convex front grip face 114 and a middle of the curved convex rear support face 116, the median plane P1 forming an angle α with a reference plane XX parallel to the blade 200.

[0049] In a preferred embodiment, the angle α is between 5° and 10°, advantageously 8°.

[0050] Unexpectedly, this inclination offers unparalleled comfort in gripping the handle 100 according to the invention, whatever the application position, and for a majority of users.

[0051] As illustrated in figure 7 , the cusp zone 117 according to the invention has, in an advantageous embodiment, a convex cusp curved face 117a having a radius of curvature R6 of between 0.2 and 0.6 cm, preferably 0.4 cm, and a length L6 of between 0.45 cm and 0.65 cm, preferably 0.55 cm.

[0052] This embodiment allows the tip of the thumb to be comfortably accommodated.

[0053] Alternatively, as illustrated in figure 8, the cusp zone 117 may be a simple cusp point 117b between the convex curved surface 115 and the concave support surface 122.

[0054] What is important is that the cusp zone 117, that is to say the passage between the convex curved surface 115 and the concave support surface 122, provides a hollow allowing the end of the thumb to be housed by bending the thumb in the direction of the articulation, the thumb being in contact with the convex curved surface 115.

[0055] As illustrated in Figure 9, the handle according to the invention comprises a compression part 140 extending the fixing part 130 and intended to bear against the deformable coating blade 200 when the latter is fixed to the coating knife handle.

[0056] The compression portion 140 comprises a first flat bearing surface 141 extending in the reference plane XX on one side of which the compression portion is located and on the other side of which the blade is located when the latter is fixed to the coating knife handle.

[0057] According to one embodiment of the invention, the fixing part 130 has, in the extension of the concave support face 122, a fixing heel 131 intersecting with the reference plane XX. In other words, the fixing heel 131 extends on either side of the reference plane XX.

[0058] The fixing heel 131 comprises a second flat surface 132 for fixing the blade arranged such that the first flat surface 141 and the second flat surface 132 form an open angle β between them, less than 179.9°, preferably less than 179.5°, advantageously between 177 and 179.5°.

[0059] This embodiment is particularly economical, because it allows the use of a flat blade, therefore economical to manufacture, while ensuring perfect plating of the blade against the compression part 140 when mounting the plastering knife.

[0060] In fact, the coating knife thus obtained comprises a coating knife handle according to the invention and a flat blade constrained and fixed against the second flat fixing surface 132 carried by the heel, and pressed forcefully against the first flat bearing surface 141 of the compression part 140.

[0061] In the illustrated embodiment, the second flat fixing surface 132 is arranged in a fixing slot 133 of the blade 200 carried by the heel 131. The slot 133 is delimited by the second flat fixing surface 132 above the blade 200, and by a fixing tab 134 which forces the blade 200 against the compression portion 140 when mounting the plastering knife.

[0062] The fixing slot 133 also comprises a longitudinal groove 135, extending in the longitudinal direction L. In a complementary manner, the blade comprises reliefs intended to be inserted into the groove 135 to block the blade against the handle 100.

[0063] In a first embodiment, these reliefs are spring tabs (not shown) obtained by localized stamping of the blade and which flatten when the blade 200 is inserted into the fixing slot 133 perpendicular to the longitudinal direction L, then release into the longitudinal groove 135 to lock the blade. To remove the latter, it is sufficient to force by strongly moving the blade away from the handle perpendicular to the longitudinal direction L.

[0064] Alternatively, these reliefs are non-deformable and the blade is inserted / removed laterally relative to the handle, i.e. in the longitudinal direction.

[0065] According to other embodiments of the invention: the handle may have stiffening reinforcements inside the profile; the profile of the handle may be manufactured by extrusion and then cut to the width of the blade to distribute the pressure over this entire width; the handle may be part of an assembly also comprising a part for fixing an extension handle to this handle, the fixing part having a shape complementary to the grip 112 and lever 113 zones of the handle to be able to be secured to the handle; the assembly may also comprise an extension handle provided with said fixing part to allow the coating to be applied at a height or at a distance from the user.

Claims

1. Coating knife handle (100) composed of a profile extending along a longitudinal direction and comprising a gripping part (110) linked by a central part (120) to a fixing part (130) for fixing an edge of a coating blade (200), wherein the gripping part (110) has a convex top face (111) intended to receive the palm and the fingers of the hand of the user, the convex curved top face (111) being linked to the central part (120), on the one hand: • by an engagement zone (112) comprising a front convex curved engagement face (114), against which the fingers of the user can fold, and linked directly to a concave curved engagement face (121) situated at the front of the central part (120), characterized in that the convex top face (111) is linked to the central part (120), and on the other hand, • by a lever zone (113) comprising a convex bottom lever face (115) situated under the convex top face (111), against which the thumb of the user can fold in the direction of the joint, and linked by a switchback zone (117) to a concave bearing face (122) situated behind the central part (120), the switchback zone forming a hollow allowing the end of the thumb to be housed by folding the thumb in the direction of the joint.

2. Coating knife handle (100) according to Claim 1, wherein the convex top face (111) has a main radius of curvature (R1) of between 9 and 11 cm, preferably 10 cm.

3. Coating knife handle according to either one of Claims 1 and 2, wherein the convex bottom lever face (115) has a radius of curvature (R2) of between 7 and 9 cm, preferably 8 cm.

4. Coating knife handle (100) according to any one of Claims 1 to 3, wherein the front convex curved engagement face (114) and the concave curved engagement face (121) have a radius of curvature (R3-R4) of between 0.8 and 1.2 cm.

5. Coating knife handle according to any one of Claims 1 to 4, wherein the concave bearing face (122) has a radius of curvature (R5) of between 2.4 and 2.8 cm, preferably 2.6 cm.

6. Coating knife handle according to any one of Claims 1 to 5, wherein the switchback zone (117) has a convex curved switchback face (117a) having a radius of curvature (R6) of between 0.2 and 0.6 cm, preferably 0.4 cm.

7. Coating knife handle according to any one of Claims 1 to 6, wherein the convex top face (111) is linked to the convex bottom lever face (115) by a convex curved bearing face (116) having a radius of curvature (R7) of between 0.6 and 0.9 cm, preferably 0.75 cm.

8. Coating knife handle according to any one of Claims 1 to 7, wherein, seen in cross section of the handle, the gripping part has a median plane (P1), passing through a middle of the front convex curved engagement face (114) and a middle of the rear convex curved bearing face (116), the median plane (P1) forming an angle (α) with the reference plane (X-X).

9. Coating knife handle (100) according to any one of Claims 1 to 8, wherein the fixing part (130) is extended by a compression part (140) intended to bear against the deformable coating blade when the latter is fixed to the coating knife handle, the compression part (140) comprising a first flat bearing surface (141) extending in a reference plane (X-X) on one side of which the compression part (140) is located and on the other side of which the blade (200) is located when the latter is fixed to the coating knife handle, and wherein the fixing part (130) has, furthermore, a fixing heel (131) secant with the reference plane (X-X) and comprising a second flat fixing surface (132) for fixing the blade, the first and the second flat surfaces (141-132) forming an open angle (β) between them, less than 179.9°, preferably less than 179.5°, advantageously between 177 and 179.5°.

10. Coating knife, characterized in that it comprises a coating knife handle according to Claim 9, and a constrained flat blade fixed by force against the second flat fixing surface borne by the heel, and pressed by force against the first flat bearing surface of the compression part.

11. Assembly comprising a handle according to any one of Claims 1 to 9 and a fixing part for fixing an extension handle to this handle, characterized in that the fixing part has a form complementing the engagement and lever zones of the handle to be able to be attached to the handle.

12. Assembly according to Claim 11, comprising an extension handle provided with said fixing part.