DEVICE FOR SEPARATING PAPER SECTIONS FROM A PAPER WEB WOUND ONTO A PAPER ROLL, AS WELL AS A KNIFE FOR SEPARATING THE PAPER SECTIONS

Abstract

The invention relates to a device for separating paper sections (74) from a paper web wound onto a paper roll and for allowing easy manual access to the paper web that follows after the separated paper section, whereby the device comprises a cutting cylinder (40), which extends over at least the paper width, and a knife (42) that extends essentially over the entire roller width, whereby the knife (42) comprises a blade (114) and a series of teeth (120, 122, 124, 126), which are arranged spaced apart along the length of the blade, whereby the groups of teeth (120, 122, 124, 126) are separated from each other by cut-outs (128, 130, 132), and whereby the cutting roller (40) is associated with a pressure roller (44), which has a slit-shaped opening (46) and is coupled to the cutting roller (40). In order to be able to cut and dispense paper webs of high strength and elasticity reliably and trouble-free, it is intended that each of the cut-outs (128, 130, 132) comprises two cutting edges (162, 164, 166, 168), which extend parallel to each other and transversely to the longitudinal extent of the knife (42), that at least one of the cutting edges (162, 164, 166, 168) is a cutting edge of a group of teeth adjoining the cut-out, and that the cutting roller (40) comprises along its circumferential surface (134) circumferential grooves (128, 130, 132), each of which corresponds to one of the cut-outs.

Claims

1. A device (26) for separating paper sections (74) from a paper web (24) wound onto a paper roll (22) that provides easy access to the following paper web after the separated paper section has been released, whereby the device (26) comprises at least one cutting roller (40) with a width that corresponds to at least the paper width, with a fixed knife (42) that protrudes from a roller shell and substantially extends across the entire roller width, whereby the knife (42) comprises one knife blade (114) and a series of teeth (120, 122, 124, 126), which are spaced apart along the length of the knife blade (114), whereby the teeth (120, 126) or groups of teeth (122, 124) are separated from each other by cut-outs (128, 130, 132), and whereby the cutting roller (40) is associated with a pressure roller (44), which has a slit-shaped opening (46) and is coupled with the cutting roller (40), characterized in that each of the cut-outs (128, 130, 132) has two cutting edges (162, 164, 166, 168), which extend in parallel to each other and transversely to the longitudinal extent of the knife (42), in that at least one of the cutting edges (162, 164, 166, 168) is a cutting edge of a group of teeth (122, 124) that borders the cut-out (128, 130, 132), and in that the cutting roller (40) comprises along its circumferential surface (134) circumferential grooves (136, 138, 140), each of which corresponds to one of the cut-outs (128, 130, 132).

2. The device of claim 1, characterized in that the slit-shaped opening (46) of the pressure roller (44) comprises bridges (106, 108, 110) that extend along the circumferential direction, whereby a width and a separation of the bridges (106, 108, 110) correspond to a width and a separation of the cut-outs (128, 130, 132) in the knife, so that during a relative movement between the cutting roller (40) and the pressure roller (44), the bridges (106, 108, 110) engage into the cut-outs (128, 130, 132) of the knife and interact with the adjoining cutting edges (162, 164, 166, 168) in a scissor-like manner.

3. The device of claim 1, characterized in that the knife (42) comprises a knife edge (112) that protrudes from the cutting roller (40) and forms an angled section.

4. The device of claim 3, characterized in that the angled section (112) comprises the teeth (120, 126) or groups of teeth (122, 124) and is angled relative to the knife blade (144) along a deflection line at an angle ? with 15????50?, preferably ?=35?.

5. The device of claim 1, characterized in that the cutting roller (40) comprises two sections (116, 118), which preferably are embodied semi-circularly, and in that the blade (114) of the knife is fixed in position, such as clamped between the semi-circular sections (116, 118).

6. The device of claim 2, characterized in that the separation of the bridges (106, 108, 110) of the pressure roller (44) corresponds to a width of the group of teeth (122, 124) of the knife edge.

7. The device of claim 1, characterized in that the groove (136, 138, 140) is embodied with a width and a depth that correspond to the width and the depth of the cut-out (128, 130, 132).

8. A knife (42) for a device (26) for separating paper sections (74) from a paper web (24) wound onto a paper roll (28), whereby the knife (42) comprises a knife blade (114) with teeth (120, 126) and/or groups of teeth (122, 124), which are arranged spaced apart relative to each other along the length of the knife blade (114), whereby the teeth (120, 126) and/or groups of teeth (122, 124) are separated from each other by cut-outs (128, 130, 132), characterized in that the cut-outs (128, 130, 132) comprise two cutting edges (162, 164, 166, 168) that extend parallel to each other and transversely relative to the longitudinal extent of the knife (42), in that at least one of the cutting edges is a cutting edge (162, 164, 166, 168) of a group of teeth (122, 124) adjoining the cut-out, and in that the cutting edges (162, 164, 166, 168) of the groups of teeth (122, 124) possess edges (154, 156; 158, 160) that rise along the direction towards the cut-out (128, 130, 132).

9. The knife of claim 8, characterized in that the groups of teeth (120, 122, 124, 126) are angled with respect to the blade (144) along a deflection line by an angle ? with 15????55?, preferably ?=35?.

10. The knife of claim 8, characterized in that the groups of teeth (120, 122, 124, 126) comprise outer teeth (120, 126), bordering the lateral edge of the blade, as well as at least two inner groups (122, 124) of teeth, whereby the geometry of a cutting edge of the inner groups of teeth is embodied in a W-shape.

11. The knife of claim 8, characterized in that the cutting edges (162, 164, 166, 168) of the inner groups (122, 124) of teeth that border the cut-outs (130) extend parallel relative to each other.

12. The knife of claim 8, characterized in that the width and the depth of the groove (136, 138, 140) corresponds to the width and the depth of the cut-out (128, 130, 132).

13. The knife of claim 8, characterized in that the knife (42) is accommodated in a cutting roller (40), and in that the cutting roller (40) along its circumferential surface (134) possesses circumferential grooves (136, 138, 140), each of which corresponds to one of the cut-outs (128, 130, 132).

Description

[0025] Further details, advantages, and features of the invention are not only found in the claims, the characteristic features listed thereinindividually and/or in combinationbut also in the following description of the figures.

[0026] The figures show:

[0027] FIG. 1 shows a front view of a device for dispensing paper sections of a predetermined length without the covering hood,

[0028] FIG. 2 shows in a sectional view the device of FIG. 1 along a section line A-A, with paper roller, cutting roller, and pressure roller,

[0029] FIG. 3 shows a lateral view of the device of FIG. 1, from the left, with gearwheel transmission and return spring,

[0030] FIG. 4a) shows a lateral view of the gearwheel transmission with return spring of FIG. 3 in its neutral position,

[0031] FIG. 4b) shows in a sectional view the roller arrangement in its neutral position,

[0032] FIG. 5a) shows a lateral view of the gearwheel transmission in the knife-entry position,

[0033] FIG. 5b) shows in a sectional view the roller arrangement in the knife-entry position,

[0034] FIG. 6a) shows a lateral view of the gearwheel transmission in the engaged-knife position,

[0035] FIG. 6b) shows in a sectional view the roller arrangement in the engaged-knife position,

[0036] FIG. 7a) shows a lateral view of the gearwheel transmission in the knife-withdrawal position,

[0037] FIG. 7b) shows in a sectional view the roller arrangement in the knife-withdrawal position,

[0038] FIG. 8 shows a lateral view of the device of FIG. 1; seen from the right, with hand wheel,

[0039] FIG. 9 shows a perspective representation of a pressure roller,

[0040] FIG. 10 show a perspective representation of the cutting roller with knife,

[0041] FIG. 11a) shows a top view onto the knife, and

[0042] FIG. 11b) shows a lateral view of the knife.

[0043] FIG. 1 shows a front view of a device 10, referred to as a paper dispenser hereinafter, for dispensing paper sections of a predetermined length. The device comprises a housing 12 with a rear wall 14 to be mounted to a wall (not illustrated), as well as a covering hood 16. From the rear wall 14 extend holding elements 18, 20 for accommodating a paper roll 22. From the paper roll 22 issues a paper web 24, which is accommodated in a device 26 for separating and dispensing paper sections. The device 26 comprises a right-side wall 28 as well as a left-side wall 30, which are connected to the rear wall 14. The side walls 28, 30 are connected on the front side via a brace 32. From the brace 32 extends along the vertical direction a pressure spring 34, which is in contact with a surface 36 of the paper web 24 or the paper roll 22 and prevents creasing of the paper web 24. The pressure spring is pivotably mounted around a hinge 38 and can be pivoted laterally to the right or the left to facilitate exchanging the paper roll 22. The length of the pressure spring is such, that the pressure spring 34 in its laterally pivoted position prevents the covering hood 16 from closing.

[0044] FIG. 2 shows a sectional view of the paper dispenser 10 along the section line A-A. The device 26 comprises a cutting roller 40 with a fixed knife 42 that extends along the longitudinal axis of the cutting roller as well a pressure roller 44 with a slit-shaped opening 46, which extends along the longitudinal direction of the pressure roller 44, and into which the knife 42 can engage during a synchronous movement of the rollers 40, 44. Each of the rollers 40, 44 is supported in the side walls 28, 30 by shaft journals 48, 50. At their ends, each of the shaft journals 48, 50 features geared wheels 52, 54 or 56, 58, which serve to couple the rollers 40, 44.

[0045] Deflecting rollers 60, 62 are provided for guiding the paper web, each of which is supported on an axle 64, 66, which extend between the side walls 28, 30.

[0046] The paper web 24 is deflected by the deflecting rolls 60, 62 and is guided along a circumferential section 72 around the pressure roller 44 by circumferential guide elements 68, 70. One end 74 of the paper web 24 is guided through a withdrawal opening 76 in the covering hood 16 and may be grasped by a user. To ensure that the end of the paper web 74 is guided into the withdrawal opening 76, a guide element is provided in the area of the withdrawal opening 76 and extends along the pressure roller 44 between the side walls 28, 30.

[0047] The guide elements 68, 70 are connected in the area of the cutting roller 40 by guide lands 71 that extend in the circumferential direction and are arranged spaced apart. The guide lands 71 serve to guide the paper web 30 in the region of the guide elements 68, 70, where the knife 42 engages into the opening 46 of the pressure roller 44.

[0048] FIG. 3 shows a lateral view of the paper dispenser 10 and illustrates the geared wheel 52 of the cutting roller that is connected to the shaft journal 48, as well as the geared wheel 56 of the pressure roller 44 that is connected to the shaft journal 50. The geared wheels 52, 56 form a gear unit with a 1:1 transmission ratio and effect a synchronous motion of the rollers in such a way that the paper web 24, which has been stretched tightly along the circumferential surface 72 of the pressure roller 44, is cut or pierced by the knife 42 when the paper end 74 is being pulled, whereby during this cutting operation the knife 42 penetrates into the slit-like opening 46.

[0049] The geared wheel 52 is coupled to the lateral wall 30 via a tension spring 80 in a way so that a pulling movement acting on the paper end 74 in the direction of the arrow 82 in accordance with FIG. 2, effects a rotation of the pressure roller 44 in the direction of the arrow 84, on account of a frictional engagement between the paper web 24 and the circumferential surface of the pressure roller. Due to the coupling of the geared wheels, the geared wheel 48 is moved in the direction of the arrow 86, which results in a tensioning of the tension spring 80. After half a rotation of the pressure roller 44, the tension spring has reached its maximum tension, so that during continued pulling of the paper end 74 the tension spring 80 contracts, which effects an automatic further conveyance, which in turn guides a new paper end from the opening 76.

[0050] FIGS. 4 to 7 show individual positions of the cutting roller 40 relative to the pressure roller 44 when a pulling motion acts on the paper end 74.

[0051] FIGS. 4a) and 4b) show the geared wheels 48, 50 and the rollers 40, 44 in a neutral position, in which the tension spring 80 is relaxed. In this, an effective line 88 of the tension spring 80 extends substantially perpendicular to a line 90 that connects the shaft ends 48, 50. The paper web 24 is in contact with the pressure roller 44 along its circumferential surface and is pulled tight in the area of the slit-shaped opening 46.

[0052] FIGS. 5a) and 5b) show the geared wheels 48, 50 as well as the rollers 40, 44 in a knife-engaging position, e.g. after a rotation of approximately 25?, whereby the knife 42 penetrates the paper web and enters into the slit-shaped opening 46, which starts the separation process. In this position, the knife 42 comes into contact with the paper web. Pulling the paper end 74 even further results in an at last sectional separation (perforation) of the paper section by the penetration of the knife 42 into the slit-like opening 46.

[0053] FIGS. 6a) and 6b) show the geared wheels 46, 50 and the rollers 40, 44 in the engaged-knife position, in which the knife 42 is completely accommodated in the slit-like opening 46.

[0054] Pulling the paper end 74 results in the tension spring 80 being further tensioned, whereby pursuant to FIG. 7a) and FIG. 7b) the knife 42after a rotation of approximately 120?is no longer engaged in the slit-like opening 46 (knife withdrawal position).

[0055] Pulling the paper end 74 serves to further tension the tension spring 80, until the rollers 40, 44 have completed half a rotation. After the effective line 88 of the tension spring 80 has crossed the centre of the geared wheel, the contraction of the tension spring 80 results in an automatic further conveyance of the paper web 24, together with the separated paper section. Subsequently, the paper section 74 can be separated from the paper web 24 along the perforated cutting line.

[0056] FIG. 8 shows a lateral view of the paper dispenser 10 from the right side and shows the geared wheels 54 and 58, which are in an engaged position. A hand wheel 92 is coupled to the geared wheel 58 for the pressure roller 44. The hand wheel 92 facilitates a manual operation of the pressure roller 44 for threading the paper web 24, e.g. after the paper roll 22 has been exchanged.

[0057] The geared wheel 58 of the pressure roller 44 interacts with a locking lever 94, which is pivotably mounted on a rod 96. The locking lever locks the geared wheel 58 along the direction of the arrow 94.

[0058] FIG. 9 shows a perspective representation of the pressure roller 44 with the shaft 50 and the slit-shaped opening 46. The slit-shaped opening 46 extends along the longitudinal direction of the pressure roller 44 all along the latter's longitudinal extent. The slit-shaped opening 46 comprises four sections 98, 100, 102, 104, which are separated by bridges 106, 108, 110 extending in the radial and the circumferential direction.

[0059] FIG. 10 shows a perspective representation of the cutting roller 40 with the fixed knife 42. The knife 42 comprises a knife edge 112 as well as a knife blade 114, which is accommodated in the cutting roller 40. In the illustrated embodiment example, the cutting roller 40 comprises two elements 116, 118, which possess a semi-circular cross-section, and in between which the knife blade 114 is clamped.

[0060] The knife edge 112 comprises four sections 120, 122, 124, 126, which are separated from each other by cut-outs 128, 130, 132. The individual sections 120, 122, 124, 126 of the knife edge 112 engage into the sections 98, 100, 102, 104 of the slit-shaped opening 46, whereby the bridges 106, 108, 110 engage into the cut-outs 128, 130, 132. The outer surface 134 of the cutting roller 40 is provided with circumferential grooves 136, 138, 140, which corresponding to the cut-outs 128, 130, 134. The outer surface 134 of the cutting roller 40 is provided with circumferential grooves 136, 138, 140, which correspond to the cut-outs 128, 130, 134. The circumferential grooves 136, 138, 140 engage into the guide lands 71 of the circumferential guide elements 68, 70, whereby the guide lands extend circumferentially and transversely to the longitudinal axis of the cutting roller 42, so that a section of the circumferential surface 134 of the cutting roller 42 together with the inner surface of the guide lands 71 forms a guide surface, which simplifies the guiding of the paper web, in particular during the threading process.

[0061] FIG. 11a) shows a top view onto the knife 42, comprising the knife edge 112 as well as the knife blade 114. The knife 42 is embodied as a stamped part.

[0062] FIG. 11b) shows a lateral view of the knife 42. The knife edge 112 is bent relative to the knife blade 114 by an angle ?, with ? in the range of 20????60?, preferably ?=30?. This ensures that the knife edge 112 enters the slit-shaped opening 46 at an optimum angle for cutting the paper web 24.

[0063] In accordance with an aspect of the invention with independent inventive merit, the outer sections 120, 126 possess a triangular cutting edge, whereby sections 142, 144 or 146, 148 of the cutting edge are embodied with an obliquely downward shape in the direction towards the lateral edges 150, 152 or the cut-outs 128, 132.

[0064] The invention's embodiment is characterized in that the cutting edges of the central sections 122, 124 have flanks 154, 156; 158, 160 that rise in the direction of the cut-outs 128, 130, 132, which serves to ensure that cutting edge sections 162, 164, 166, 168 of the longest possible length are formed adjacent to the cut-outs 128, 130, 132, whereby the cutting edge sections interact with the bridges 106, 108, 110 of the pressure roller to cut the paper web in a precise manner, which in turn facilitates a simple tear-off action.

[0065] With respect to the invention's embodiment of the knife edge 112, it should also be noted that because of the cut-outs 128, 130, 132 the paper web 24 is only subjected to a type of perforation, instead of being subjected to a complete continuous cut, so that even after the cutting process, the automatic advance due to the tension spring 80 is sufficient to transport the paper section 74 to be torn off out of the paper dispenser, without any risk of a paper jam. After the perforated paper section 74 has been dispensed through the opening 76, it may simply be torn off by a user, which separates the remaining strands in the paper web 24.

[0066] This requires only minimal pulling forces, whereby a further conveyance of the paper web 24 is prevented by the restoring force of the tension spring 80.

[0067] As a result of the invention's embodiment of firstly the knife edge 112 in interaction with the slit-shaped opening 46 with the sections 98, 100, 102, 104 as well as the bridges 106, 108, 110, and secondly by fine-tuning the spring tension of the tension spring 80, the invention's embodiment allows the cutting or rather perforating of paper webs of different density and strength. In particular, the invention's paper dispenser 10 is to convey paper webs with a density of 2?25 g per mm.sup.2, i.e. paper webs that usually can only be used in electrically operated paper dispensers. In the prior art, mechanically operated paper dispensers are usually operated using thin paper webs with a density of 2?17 g per mm.sup.2, i.e. single-layer paper.