Dispensing mechanism for a paper dispenser

Description

[0001] The present invention relates to the field of paper dispensers and is directed to a dispensing mechanism for a paper dispenser. The present invention also relates to a paper dispenser equipped with such a mechanism.

[0002] Paper dispensers with a dispensing mechanism and a drive roller, such as a dispensing drum, are well known in the field, as described in US patent 6446901 B1. A dispensing drum typically feeds and cuts a paper strip into sheets and can be operated in various ways, for example, manually using a rotary knob, with an electric motor, or by means of a spring-loaded mechanism activated by a user pulling on the paper strip. The dispensing drum contains a cutting blade that can move out of the drum, thus cutting the paper strip extending along the periphery of the drum. Typically, each revolution of the dispensing drum corresponds to the length of one sheet of paper, so the cutting blade is extended and retracted once for each revolution.The dispensing drum is often also a drive element, meaning that it extracts paper from the paper supply and then feeds it to a user.

[0003] Such types of paper dispensers are generally equipped with anti-reverse means which prevent the dispensing drum from moving in the opposite direction when cutting the paper, which could lead to incomplete cutting of the paper, or even to the complete winding of the paper strip around the dispensing drum, which could generate damage in the dispensing mechanism.

[0004] The anti-return devices generally used consist of gear and ratchet type mechanisms, which are mounted at the bearing of the distribution drum.

[0005] The use of such backflow prevention devices poses a number of problems.

[0006] On the one hand, their size is relatively large. This makes it difficult to offer relatively compact paper dispensers.

[0007] On the other hand, when using the dispensing mechanism, these anti-return means can generate relatively high noise levels, which may be deemed unacceptable to users.

[0008] One objective of the present invention is to solve the problems identified above associated with prior art paper dispensers by proposing a dispensing mechanism for a paper dispenser that is both compact and low noise.

[0009] To this end, according to a first aspect, the invention relates to a dispensing mechanism for a paper dispenser, comprising: a movable drive roller rotating about an axis of rotation, said drive roller being intended to support a paper strip at the level of an external surface and being provided with a shaft and a peripheral slot, said peripheral slot opening into an internal cavity of the drive roller, a cutting blade supported by the drive roller, said cutting blade being able to move under the action of movement means between a first position, called the rest position, in which the cutting blade is housed entirely inside the internal cavity of the drive roller, being positioned radially under the external surface of the drive roller, and a second position, called the cutting position, in which the cutting blade protrudes radially from said external surface at the level of the peripheral slot,and anti-reverse means suitable for allowing the drive roller to rotate in a first direction and preventing the drive roller from rotating in a second direction opposite to the first direction, in which said anti-reverse means comprise at least one unidirectional ball bearing on which the shaft of the drive roller is mounted.

[0010] In this configuration, the distribution mechanism is more compact thanks to the use of a unidirectional ball bearing with a reduced footprint. Furthermore, such a unidirectional ball bearing is also characterized by low noise levels during operation.

[0011] According to other features, the distribution mechanism of the invention comprises one or more of the following optional features considered alone or in all possible combinations: The means of movement include a blade actuator pivotally mounted on the drive roller around a pivot axis and on which the cutting blade is fixed, the blade actuator comprising a follower roller eccentric relative to the pivot axis and bearing against a cam, and a spring capable of causing a pivoting of the blade actuator when the follower roller is in an extreme position corresponding to the cutting position of the cutting blade.The cam has a closed contour with a first curved section extending in an arc around the axis of rotation of the drive roller between a first end edge and a second end edge, a second curved section extending from the first end edge of the first curved section to a pointed end edge corresponding to the extreme position of the follower roller, and a third curved section extending from said pointed end edge to the second end edge of the first curved section. The follower roller is close to or in contact with the first end edge of the first curved section of the cam when the cutting blade is in its rest position. The second curved section of the cam has a concave face towards the axis of rotation of the drive roller, and the third curved section of the cam has a convex face towards the second curved section of the cam.The drive roller is provided with a series of annular grooves spaced axially apart, at least one of said annular grooves housing at least partially a tooth projecting radially from a retaining bar arranged parallel to the drive roller, said tooth being configured to prevent the paper web from winding around a peripheral portion of said drive roller located downstream of said tooth in the direction of rotation of the drive roller. The distribution mechanism further comprises two guide rollers, respectively an upper guide roller and a lower guide roller, rotatable about axes of rotation parallel to the axis of rotation of the drive roller, said guide rollers being adapted to press the paper web against the outer surface of the drive roller.The dispensing mechanism further includes a rotary knob coupled to the drive roller shaft, said rotary knob being manually actuated to rotate the drive roller, particularly when introducing a new strip of paper into the dispensing mechanism. The rotary knob has two cavities separated by a central segment, said cavities being designed to receive a user's fingers.

[0012] According to another aspect, the invention relates to a paper dispenser for distributing a strip of paper, comprising a distribution mechanism as defined above.

[0013] The invention will be better understood upon reading the following non-limiting description, made with reference to the figures attached hereto. There figure 1 represents a perspective view of a distribution mechanism according to one embodiment of the invention. figure 2 represents a perspective view of the distribution mechanism of the figure 1 . There figure 3 represents an exploded perspective view of the drive roller of the distribution mechanism of the figure 1 . There figure 4 is a first cross-sectional view of the mechanism of the figure 1 showing the position of the blade actuator in the rest position of the cutting blade. figure 5a is a second cross-sectional view of the mechanism of the figure 1 raising the cutting blade position to its resting position. figure 5b is a side view of the mechanism of the figure 1 showing the position of the return spring in the rest position of the cutting blade. figure 6a is a view similar to the figure 5a with the cutting blade in its cutting position. figure 6b is a view similar to the figure 5b with the cutting blade in its cutting position. figure 7a is a view similar to the figure 5a the cutting blade being in an intermediate position between its cutting position and its resting position. figure 7b is a view similar to the figure 5b , the cutting blade being in the intermediate position of the figure 7a .

[0014] With reference to figures 1 et 2 , a distribution mechanism is represented according to an embodiment according to the invention.

[0015] This distribution mechanism 10 includes in particular an external frame formed of a lower panel 11, an upper panel 12, a right side panel 13 and a left side panel 14. The external frame surrounds a drive roller 15 mounted movably to rotate about an axis of rotation X1 respectively to the right side panel 13 and the left side panel 14. Each side panel is formed of two parts connected to each other, for example by clipping, namely a bearing panel, respectively 13a and 14a, and a cover plate, respectively 13b and 14b. The cover plate 13b of the right side panel 13 advantageously has an arc-shaped contour 131 intended to fit the external shape of a rotary knob 31 coupled to a shaft of the drive roller 15. The rotary knob 31 is provided in particular with two cavities 311, 312 separated by a central segment 313, said cavities 311, 312 being suitable for receiving the fingers of a user.Thus configured, the rotary knob 31 can be turned manually by a user so as to allow the rotation of the drive roller 15. Such a maneuver will be implemented in particular when introducing a new strip of paper into the distribution mechanism.

[0016] The distribution mechanism 10 further includes two guide rollers 16, 17, respectively an upper guide roller 16 and a lower guide roller 17, movable in rotation respectively around axes of rotation X3, X4 parallel to the axis of rotation X1 of the drive roller 15. As explained in detail in the following paragraphs, the guide rollers 16, 17 have the function of pressing the paper strip against the external surface of the drive roller 15, allowing better distribution of the paper.

[0017] Furthermore, the distribution mechanism 10 is equipped with a retaining bar 18 which is arranged parallel to the drive roller 15. This retaining bar 18 has several teeth 181 which project radially from an outer face that faces the drive roller 15. Each of these teeth 181 is aligned with an annular groove 153 formed on the outer periphery of the drive roller 15. As shown in the figure 2 The drive roller 15 may be provided with a series of such annular grooves 153 along its outer surface, said grooves being spaced axially apart. In the normal operation of the dispensing mechanism, each of the teeth 181 is housed at least partially within the corresponding annular groove 153. Thus configured, the teeth 181 will prevent the paper strip from wrapping around a peripheral portion of said drive roller 15 located downstream of said teeth in the direction of rotation of the drive roller 15. This will prevent damage to the dispensing mechanism in the event that a partially cut paper strip creates a jam inside the mechanism.

[0018] As depicted on the figure 2 The guide rollers 16 and 17 are advantageously equipped at each end with hubs fitted with bidirectional ball bearings 19, thus allowing bidirectional rotation of the guide rollers 16 and 17 around their respective axes X3 and X4. Conversely, the drive roller 15 is equipped at one end with a hub fitted with a bidirectional ball bearing 19 and at its opposite end with a hub fitted with a unidirectional ball bearing 21. This unidirectional ball bearing 21 acts as a backstop, allowing the drive roller 15 to rotate in a first direction, namely clockwise in the embodiment shown, and preventing its rotation in a second direction opposite to the first, namely counterclockwise in the embodiment shown. This unidirectional ball bearing 21 has the advantage of being both compact and quiet.

[0019] With reference to the figure 3 An exploded view of the drive roller 15 visible on the is shown. figure 2 This drive roller 15 is formed of a lower part 151 and an upper part 152, said lower and upper parts fitting one inside the other. Each of the parts 151, 152 is defined by two left and right end walls in the shape of a half-disc, respectively 151a, 151b and 152a, 152b, connected by a longitudinal wall of substantially semi-cylindrical shape, respectively 151c, 152c. The longitudinal walls 151c, 152c are covered with several strips of rough material 156 designed to improve the adhesion of the paper web when it comes into contact with the drive roller 15. The lower part 151 incorporates a left hub 154 projecting axially from the left end wall 151a and a right hub 155 projecting axially from the right end wall 151b. These hubs 154, 155 fit into corresponding notches 152e in the end walls 152a, 152b.In one embodiment of the invention (not shown), these hubs 154, 155 may form the two ends of a single shaft passing through the drive roller 15. As explained previously, the left hub 154 will be mounted on the left side panel 14 via the bidirectional ball bearing 19, and the right hub 155 will be mounted on the right side panel 13 via the unidirectional ball bearing 21. The longitudinal wall 151c of the lower part 151 is notably delimited by an end edge 151d which faces an end edge 152d of the longitudinal wall 152c of the upper part 152. The end edges 151d and 152d are angularly offset so that they define a slot or opening 159a at the periphery of the drive roller 15. This peripheral slot 159a opens into an internal cavity 159b of the drive roller. 15.This internal cavity 159b is specifically configured to fully house a cutting blade 22 in a rest, or non-operating, position of the cutting blade 22 (as illustrated on the . figure 5a The cutting blade 22 is provided with several cutting portions 221, 222, 223 separated by grooves 224, 225 oriented radially with respect to the axis of rotation X1. The cutting portions 221-223 have a serrated cutting edge designed to cut the paper strip when it comes into contact with it in a cutting position of the cutting blade (as illustrated in the figure 6a ). Once cut, the strip of paper will then present a series of three pre-cut segments connected by bridges of material that can easily break when the user pulls on the paper.

[0020] To move from its rest position to its cutting position, the cutting blade 22 is pivotally connected to the drive roller 15 around a rotation axis X2 which is parallel to the rotation axis X1. For this purpose, it is fixed at its left end to a left connecting element 24 and at its right end to a right connecting element 23. The left connecting element 24 has a substantially cylindrical shape and is designed to fit inside semi-circular notches 157a, 158a formed respectively in the left end walls 151a, 152a so that the left connecting element 24 can pivot around the rotation axis X2.The right-hand connecting element 23 comprises, at one end, a cylindrical portion 231 to which the cutting blade 22 is fixed and which is axially aligned with the left-hand connecting element 24, and at a second end, which is radially offset from the first end, a cylindrical follower roller 233 oriented towards the right-hand side panel 13. The cylindrical portion 231 and the follower roller 233 are connected to each other by means of a radially oriented arm 232. The cylindrical portion 231 is designed to fit inside semicircular notches 157b and 158b formed respectively in the right-hand end walls 151b and 152b so that the right-hand connecting element 23 can pivot about the axis of rotation X2.

[0021] As depicted on the figure 4 The bearing panel 13a is provided on its inner face with a rib 29 against which the follower roller 233 rests during the rotation of the drive roller 15 around the axis of rotation X1. The rib 29 thus forms a cam track for the follower roller 233.This cam track has a closed contour with several sections, respectively a first curved section C1 extending in an arc around the axis of rotation X1 of the drive roller 15 between a first end edge E1, corresponding substantially to a so-called rest position (shown in solid lines) of the follower roller 233, and a second end edge E2; a second curved section C2 extending from the first end edge E1 of the first curved section C1 to a pointed end edge E3 corresponding to an extreme position PC (shown in dashed lines) of the follower roller 233; and a third curved section C3 extending from said pointed end edge E3 to the second end edge E2 of the first curved section C1, along which the follower roller 233 can be in a so-called return position PR (shown in dashed lines). As shown in the figure. figure 4 The second curved section C2 has a concavity facing the axis of rotation X1 of the drive roller 15, and the third curved section C3 has a convexity facing the second curved section C2. Each position of the follower roller 233 along the cam path defined by the rib 29 will generate a particular orientation of the arm 232 of the straight connecting element 23 with respect to the plane defined by the axes of rotation X1 and X2, and, consequently, a particular orientation of the cutting blade 22 with respect to said plane.As described later, the movement of the follower roller 233 along the cam 29 will occur successively, along the second curved section C2, due to the movement made by the paper strip under the action of the traction exerted by the user and, along the third and first curved sections C3 and C1, under the action of a return spring 25 connected, on the one hand, to the left side panel 14, and, on the other hand, to an articulated lever 27 coupled to the left connecting element 24 (represented in particular on the . figure 2 ). The combined action of the return spring 25 and this lever 27 will thus allow the cutting blade 22 to return from its cutting position PC to its rest position, once the strip of paper has been completely cut.

[0022] The operation of the distribution mechanism 10 will be described below in relation to the figures 5a, 5b , 6a, 6b , 7a et 7b .

[0023] With reference to the figure 5a The cutting blade 22 is shown in its rest position, as illustrated on the figure 4 In this position, the cutting blade 22 is entirely located inside the internal cavity 159b of the drive roller 15, positioned below the peripheral slot 159a. Thus, it is not in contact with a paper strip 30 which passes through the distribution mechanism 10, being wound successively around the upper guide roller 16, the drive roller 15 and the lower guide roller 17.

[0024] At this resting position of the cutting blade 22, and as shown on the figure 5b This corresponds to a specific angular positioning of the rotation axis X2 relative to the rotation axis X1. In this specific angular positioning, the articulated lever 27 has a specific configuration in which a first arm 271 of said lever 27, which can pivot about the rotation axis X1, is oriented downwards and is substantially perpendicular to a second arm 272 of said lever 27, which can pivot about the rotation axis X2. A free end of the second arm 272 is connected to the return spring 25 at a first end 251, the return spring 25 being connected to the left side panel 14 at a second end 252. In this specific configuration of the articulated lever 27, the return spring 25 is not subjected to an extension of its rest length and does not exert a restoring force.

[0025] With reference to the figure 6a The cutting blade 22 is shown in its cutting position PC, as illustrated on the figure 4 In this position, the cutting blade 22 is partially positioned outside the internal cavity 159b of the drive roller 15, being at least partially positioned above the peripheral slot 159a. Thus, it comes into contact with the paper strip 30. The transition from the rest position to the cutting position results from the displacement D of the paper strip 30 under the effect of the tension exerted by the user. Due to its contact with the external surface 156 of the drive roller 15, the paper strip 30 has generated a rotation of said drive roller 15 around the axis of rotation X1 in a clockwise direction.

[0026] At this cutting position of the cutting blade 22, and as shown on the figure 6b , corresponds to a specific angular positioning of the rotation axis X2 relative to the rotation axis X1. In this specific angular positioning, the articulated lever 27 has a specific configuration in which the first arm 271 is oriented obliquely downwards and is substantially aligned with the second arm 272. In this specific configuration of the articulated lever 27, the length of the return spring 25 between its ends 251, 252 is at its maximum: the return spring 25 therefore exerts a restoring force tending to return the articulated lever 27 to its specific position shown in the figure 5b .

[0027] With reference to the figure 7a The cutting blade 22 is shown in its return position PR, as illustrated on the figure 4 In this position, the cutting blade 22 is again positioned inside the internal cavity 159b of the drive roller 15, positioned below the peripheral slot 159a. Thus, it is no longer in contact with the paper strip 30. The transition from the cutting position to the return position results from the complete cutting of the paper strip 30 under the action exerted by the user, which has caused a tear in the material bridges. Due to the restoring force exerted by the spring 25, the drive roller 15 has moved around the axis of rotation X1 in a clockwise direction. It should be noted that this rotation of the drive roller 15 cannot be counterclockwise due to the presence of the unidirectional ball bearing 21.

[0028] At this return position of the cutting blade 22, and as shown on the figure 7b This corresponds to a specific angular positioning of the rotation axis X2 relative to the rotation axis X1. In this specific angular positioning, the articulated lever 27 has a specific configuration in which the first arm 271 is oriented obliquely upwards and is substantially perpendicular to the second arm 272. In this specific configuration of the articulated lever 27, the length of the return spring 25 between its ends 251, 252 is slightly greater than its rest length: the return spring 25 therefore exerts a restoring force tending to return the articulated lever 27 to its specific position shown in the figure. figure 5b .

Claims

1. A dispensing mechanism (10) for a paper dispenser, comprising: - a drive roller (15) movable in rotation about an axis of rotation (X1), said drive roller (15) being intended to support a paper web (30) at an outer surface (156) and being provided with a shaft (155) and a peripheral slot (159a), said peripheral slot (159a) opening into an internal cavity (159b) of the drive roller (15), - a cutting blade (22) supported by the drive roller (15), said cutting blade (22) being able to move under the action of displacement means (23, 25, 27) between a first position, referred to as a rest position, in which the cutting blade (22) is fully housed within the internal cavity (159b) of the drive roller (15), being positioned radially below the outer surface (156) of the drive roller, and a second position, referred to as a cutting position, in which the cutting blade (22) projects radially from said outer surface (156) at the peripheral slot (159a), and - anti-reverse means (21) capable of allowing the drive roller (15) to rotate in a first direction and of preventing the drive roller (15) from rotating in a second direction opposite to the first direction, characterized in that said anti-reverse means comprise at least one one-way ball bearing (21) on which the shaft (155) of the drive roller (15) is mounted.

2. The dispensing mechanism (10) according to claim 1, characterized in that the displacement means comprise a blade actuator (23) pivotally mounted on the drive roller (15) about a pivot axis (X2) and to which the cutting blade (22) is fastened, the blade actuator (23) comprising a follower roller (233) that is eccentric with respect to the pivot axis (X2) and bears against a cam (29), and a return spring (25) capable of causing the blade actuator (23) to pivot when the follower roller (233) is in an extreme position (PC) corresponding to the cutting position of the cutting blade (22).

3. The dispensing mechanism (10) according to claim 2, characterized in that the cam (29) has a closed contour having a first curved section (C1) extending in a circular arc about the axis of rotation (X1) of the drive roller (15) between a first end edge (E1) and a second end edge (E2), a second curved section (C2) extending from the first end edge (E1) of the first curved section (C1) to a pointed end edge (E3) corresponding to the extreme position (PC) of the follower roller (233), and a third curved section (C3) extending from said pointed end edge (E3) to the second end edge (E2) of the first curved section (C1).

4. The dispensing mechanism (10) according to claim 3, characterized in that the follower roller (233) is close to or in contact with the first end edge (E1) of the first curved section (C1) of the cam (29) when the cutting blade (22) is in its rest position.

5. The dispensing mechanism (10) according to any of claims 3 and 4, characterized in that the second curved section (C2) of the cam (29) has a concavity facing the axis of rotation (X1) of the drive roller (15), and the third curved section (C3) of the cam (29) has a convexity facing the second curved section (C2) of the cam (29).

6. The dispensing mechanism (10) according to any of the preceding claims, characterized in that the drive roller (15) is provided with a series of annular grooves (153) spaced apart from each other in the axial direction, at least one of said annular grooves (153) at least partially housing a tooth (181) projecting radially from a retaining bar (18) disposed parallel to the drive roller (15), said tooth (181) being configured to prevent the paper web (30) from wrapping around a peripheral portion of said drive roller (15) that is located downstream of said tooth (181) in the direction of rotation of the drive roller (15).

7. The dispensing mechanism (10) according to any of the preceding claims, characterized in that it further comprises two guide rollers (16, 17), respectively an upper guide roller (16) and a lower guide roller (17), movable in rotation about axes of rotation (X3, X4) parallel to the axis of rotation (X1) of the drive roller (15), said guide rollers (16, 17) being capable of pressing the paper web (30) against the outer surface (156) of the drive roller (15).

8. The dispensing mechanism (10) according to any of the preceding claims, characterized in that it further comprises a rotary knob (31) coupled to the shaft (154) of the drive roller (15), said rotary knob (31) being manually operable such that it allows the drive roller (15) to rotate, in particular when a new paper web (30) is introduced into the dispensing mechanism.

9. The dispensing mechanism (10) according to claim 8, characterized in that the rotary knob (31) is provided with two cavities (311, 312) separated by a central segment (313), said cavities (311, 312) being capable of receiving a user's fingers.

10. A paper dispenser for dispensing a paper web (30), comprising a dispensing mechanism (10) according to any of the preceding claims.

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