US3753379A

US3753379A - Cut-off devices for continuous rod cigarette-making machines and other similar machines

Info

Publication number: US3753379A
Application number: US00115953A
Authority: US
Inventors: D Molins; E Preston
Original assignee: Molins Ltd
Current assignee: Mpac Group PLC
Priority date: 1970-02-17
Filing date: 1971-02-17
Publication date: 1973-08-21
Anticipated expiration: 1990-08-21
Also published as: GB1316641A

Abstract

A cut-off device for a cigarette or other similar rod-making machine includes a damping member which is arranged to touch the knife of the cut-off device, at least in the event of the knife vibrating at or above a predetermined amplitude, so as to damp down vibrations of the knife.

Description

ilited States Patent Molins et al.

[451 Aug. 21, 1973 CUT-OFF DEVICES FOR CONTINUOUS ROD CIGARETTE-MAKING MACHINES AND OTHER SIMILAR MACHINES Inventors: Desmond Walter Molins; Edward George Preston, both of London, England Assignee: Molins Limited, London, England Filed: Feb. 17, 1971 Appl. No.: 115,953

Foreign Application Priority Data Feb. 17, 1970 Great Britain 7.626/70 US. Cl 83/174, 83/310, 83/340 Int. Cl A24c 5/30 Field of Search 83/174, 117, 340,

[56] References Cited UNITED STATES PATENTS 647,174 4/1900 Bagguley .1 83/310 3,645,304 2/1972 Thrasher .1 143/160 R 3,258,881 7/1966 Mason et a1... 83/174 3,532,015 10/1970 Gianese .1 83/174 Primary Examiner Donald R. Schran Attorney-Markva, Smith & Kruger 5 7] ABSTRACT A cut-off device for a cigarette or-other similar rodmaking machine includes a damping member which is arranged to touch the knife of the cut-off device, at least in the event of the knife vibrating at or above a predetermined amplitude, so as to damp down vibrations of the knife.

17 Claims, 10 Drawing Figures PATENIED W1 W 3. 753.319

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ATT'O/P/V VS CUT-OFF DEVICES FOR CONTINUOUS ROD CIGARETTE-MAKING MACHINES AND OTHER SIMILAR MACHINES This invention is concerned with cut-off devices for severing a continuous rod, for example a continuous cigarette rod, into short lengths. The invention is particularly useful for cigarette-making machines, but it can also for example be used in cigarette filter rod making machines.

Cut'off devices commonly include a ledger which moves to and fro and supports the rod while a knife is cutting the rod. One known form of ledger is described for example in British Patent No. 1,000,174. The knife moves with the rod (i.e., in the direction of axial movement of the rod) while cutting the rod and is preferably in the formof a section of a helix on a rotary member which has its axis appropriately inclined to the rod so that the section of the knife adjacent to the rod is always normal to the axis of the rod; a knife in this form is described, for example, in US. Ser. No. 783,983 filed Dec. 16, 1968.

According to the present invention a cut-off device includes a damping member which is arranged to touch the knife, at least in the event of the knife vibrating at or above a predetermined amplitude, so as to clamp down vibrations of the knife. This helps to reduce the danger of knife chipping which sometimes occurs (especially at high speeds associated for example with a speed of rotation of about 4,000 revolutions a minute or higher) and which we believe is caused by vibration of the knife.

The damping member is preferably of a plastics or other material having a low Modulus of Elasticity so as to be an effective damper. It may for example be of wood.

In one possible arrangement according to this invention the clamping member is stationary and the knife is arranged to sweep past it and in contact with it immediately after passing a grinder which sharpens the knife. Thus vibration of the knife caused by the grinder is damped. Where there are two grinders acting on opposite sides of the knife, there are preferably two damping members situated respectively downstream of the two grinders.

As an alternative (or addition) there may be one or more clamping members mounted on the ledger so as to touch the knife while it is cutting the rod.

Examples of cut-off devices according to this invention are shown in the accompanying drawings in which:

FIG. 1 is a fragmentary view of the ledger of one cutoff device taken on a section on the line I-I in FIG. 2;

FIG. 2 is a section on the line II-II in FIG. 1;

FIG. 3 is a fragmentary section on the line III-III in FIG. 1;

FIG. 4 shows a modification of part of the ledger;

FIG. 5 is a section on the line V-V in FIG. 1, showing a modified arrangement;

FIG. 6 is a view in the direction of the arrow VI in FIG. 5;

FIG. '7 is a fragmentary view of a different cut-off device, approximately in a direction upstream in relation to the movement of the rod;

FIG. 8 is a view in the direction of the arrow VIII in FIG. 7;

FIG. 9 is similar to FIG. 8 but shows a modified constructlon; and

FIG. 10 is a view inthe direction of arrow X in FIG. 9.

The ledger shown in FIGS. 1 to 3 includes a member 10 which oscillates, being pivotally carried by two parallel arms 12 and 14 and being driven horizontally to and fro by means of a connecting rod 16. The lower ends of the arms 12 and 14 (not shown) are connected to a stationary support by means of crossed springs as described in British Patent No. 1,000,174. A similar crossed spring device 18 connects the upper end of the arm 12 to the ledger member 10. The upper end of the arm 14, on the other hand, is pivotally connected to the ledger member 10 by means of a pivot pin 20 which also pivotally connects the ledger member 10 to the connecting rod 16, as shown in F IG. 3. The connecting rod 16 is forked so as to have two spaced side parts 16A and 168 which lie on opposite sides of the member 10. The pin 20 has its ends secured to the arm 14, and is surrounded by an intermediate sleeve 22 which is in turn surrounded by a part 220 of the member 10. There are needle roller bearings, as shown, between the pin 20 and the sleeve 22, and between the sleeve 22 and the member 10.

The left-hand end of the connecting rod, as viewed in FIG. 1, is connected to a crank driven from a shaft 24 which is shown diagrammatically in outline.

The ledger member 10 includes two'heads 26 and 28 which have aligned bores containing replaceable sleeves 36 through which the cigarette or other rod passes during use. The

heads

26 and 28 are split so that they can be tightened on to inner sleeves 36 by studs 38. Different sleeves 36 are used for different rod diameters.

Adjacent to the head 26 the member 10 includes a part 27 formed with a hole 29 through which a safety bar 30 extends with a precisely defined clearance. When the ledger is at its mean position as shown (i.e., as though at top dead centre) the clearance is greater below the bar than above, to allow for the downward component of movement produced by the arms 12 and 14. The bar 30 is screwed into an insulating socket 32 which is in turn carried by a stationary support member 34 secured to the frame of the machine. An electrical connection (not shown) is made to the bar 30, and a separate electrical connection is made to the member 10 of the ledger. These connections enable the bar 30 and member 10 to form part of an electrical circuit which is closed in the event of the bar 30 touching the surrounding part 27 of the member 10.

The direction of movement of the rod is from the right to the left as viewed in FIG. 1. The cut-off knife (not shown) passes between the

heads

26 and 28 of the ledger so as to cut the continuous rod intermittently into short lengths. During this cutting action, the knife advances axially with the rod in a known manner.

The part which touches the knife to damp down vibrations may be one of the sleeves 36 and especially the downstream sleeve (i.e., on the left as shown in FIG. 1). In this case the end face of the damping sleeve would be arranged to touch the knife. The damping sleeve may for example be made of the plastic known by the trade name Tufnel.

FIG. 4 shows a modified arrangement of the sleeves 36. In this example the damping sleeve 36A, which is of Tufnel. does not have its edge formed with a chamfer (like the chamfer 36B of the other sleeve) but instead has a nearly flat end face 36C which is only slightly convex. The clearance between the end faces of the two sleeves may be 8 to 12 thousandths of an inch.

In the case of a plastic or other non-metallic damping sleeve there may be a metal inner liner which defines the bore of the sleeve and guides the moving rod.

Instead of the knife damping being achieved by means of one of the sleeves, it may in general be achieved by means of one or more separate parts secured to one or both of the ledger heads 26 and 28, for example by means of the studs 38. With damping parts (for example of Tufnel) mounted on both of the ledger heads 26 and 28 the knive can be damped by contact on both sides. An example of such an arrangement is shown in FIGS. and 6.

In the arrangement shown in FIGS. 5 and 6 the sleeves 36 are of metal. Damping is achieved by contact of opposite sides of the knife with slightly convex Tufnel facings 40 and 42 bonded on to metal members consisting of

discs

44 and 46 carried by stems 48 and 50. These are secured by grub screws 52 and

54in parts

56 and 58. The drawings show the

parts

56 and 58 as being held on the

heads

26 and 28 by extended studs 38A, but one of these parts may be integral with its associated head. The stems 48 and 50 are sliding fits in the

parts

56 and 58 to allow for adjustment; alternatively one or both may be screw-threaded so that axial adjustment of the position of the Tufnel facing is made with a screwing action. The gap between the

facings

40 and 42 may for example be 8 thousandths of an inch.

The cut-off device shown in FIG. 7 is basically like that shown in the aforementioned patent application which describes in particular how the grinder 60 is moved bodily along a circular path by a mechanism 61 so as to act on the downstream side of the knife 62 (i.e., downstream in relation to movement of the rod). The knife forms part of a helix on a carrier drum 64 which rotates about an axis inclined to the rod so that the knife is normal to the rod and moves with the rod during cutting. The ledger in this case is shown diagrammatically at 66 and may be like the ledger shown in FIGS. 1 to 3 of the accompanying drawings. During each revolution of the drum 64 the knife 62 is contacted on its downstream side by the grinder 60 and on its upstream side by a grinder 68.

Adjacent to the grinder 68, and on the downstream side of the knife 62, there is a stationary damping member 70 which is arranged to contact the trailing edge 62A of the knife 62 to damp vibration caused by the grinder 68. The member 70 extends far enough in an anti-clockwise direction (see FIG. 7) to be able to damp knife vibration which exists before the knife reaches the grinder 68, but this extended path of the member 70 (i.e., to the left of the grinder 68 in FIG. 7) is intended to serve mainly as a lead in for the knife. The member 70 may for example be set in a position such that, when there is no knife vibration, the path of the trailing edge 62A of the knife converges towards the member '70 (as illustrated by the line 72 in FIG. 8, which however is shown at an exaggerated inclination to the member 70 for the sake of clarity) and only touches the member 70 right at the end. With this setting, when the knife is actually vibrating it will touch the member 70 before it reaches the end, so that contact with the member 70 will tend to damp the vibrations.

The damping member 70 is mounted as follows. The member '70. which may for example be of wood or Tufnel, is carried by a metal member 74 including a split bush 76 whichis tightened on to a pin 78 by a clamping screw 80. Thus by loosening the screw 80, the inclination of the member 70 to the path 72 of the knife edge 62A can be adjusted. The pin has an eccentric largediameter end portion 80A which is secured by a clamping screw 82 acting on a split bush 84 forming part of a fixed body 86. Thus the pin can be rotated relative to the body 86 after the screw 82 has been loosened. Owing to the eccentricity of the large-diameter portion 80A in relation to the part of the pin on which the member 74 is secured, rotation of the pin (for example by means of a screw driver inserted into a groove 80B adjusts the position of the damping member towards and away from the path 72 of the knife edge 62A; when this adjustment is made, the inclination of the damping member to the path 72 is also altered and needs to be corrected in the manner already described.

After the knife has passed the grinder 60 it is damped during each revolution by contact with a damping member 88 which also lies on the downstream side of the knife. This damping member is carried by a metal member 90 which is mounted in basically the same way as the member 74 carrying the damping member 70. it will be seen that the damping member extends as far as possible towards the ledger 66; in addition it may extend further towards the grinder 60 than is shown in FIG. 7.

When the knife 62 needs changing, it is convenient to swing the damping member 88 away from the path of the knife after loosening a clamping screw 92 (which functions like the clamping screw 82). To ensure that the clamping member is afterwards returned to precisely the same operative position, the fixed body 94 carrying the member 90 also carries an adjustable stop in the form of a screw 96 which the member 90 abuts against when it is returned to its operative position.

The damping member 88 may be set in the same position relative to the path 72 of the knife edge 62A as has been described in relation to the damping member 70.

FIGS. 9 and 10 show a modified form of adjustable mounting for the damping member 70 which is referenced 70A as the shape is slightly different from that shown in FIG. 7. A similar adjustable mounting may be used for the damping member 88 in FIG. 7.

The damping member 70A is carried by a metal member 98 which includes an integral boss 100 in which is screwed a pin 102. This pin is clamped by a screw 104 in a split bush 106A forming part of a member 106 which also includes a shank 10613 of circular cross-section which is slidable in a bore in a fixed body 108.

Rotation of the shank in the body 108 is prevented by a grub screw 110 which engages in a short axial groove 112 in the shank. However. the shank can be axially moved by means of a screw member 114 which includes a small-diameter threaded end portion 114A screwed in the end of the shank, and a larger-diameter threaded portion (with a coarser thread) screwed in a plug 116 which is itself screwed into the body 108. Thus because of the pitch difference between the pertions 114A and 1143 of the screw member, rotation of the screw member moves the shank 106B slightly in an axial direction, thus adjusting the position of the damp ing member towards and away from the path of the knife edge.

We claim:

l. A cut-off device for a continuous rod making machine, comprising a knife which forms part of a helix on a rotary member rotating about a fixed axis and at least one damping member which is positioned at the downstream side of the knife, in relation to the direction of movement of the rod, and contacts the trailing edge of the knife at least in the event of the knive vibrating at or above a predetermined amplitude, so as to damp vibrations of the knife.

2. A cut-off device according to claim 1 in which the damping member is so positioned that it contacts the knife immediately after the knife passes a grinder arranged to sharpen the knife during each revolution of the rotary member.

3. A cut-off device according to claim 2. in which there are two grinders which act successively on the opposite sides of the knife, and in which there are two damping members which respectively contact the knife to damp vibration after the knife passes each grinder.

4. A cut-off device according to claim 1 in which the damping member is arranged to be set at a slight inclination to the path of the trailing edge of the knife, the angle of inclination being adjustable.

5. A cut-off device according to claim 4 in which the position of the damping member towards and away from the path of the knife is adjustable.

6. A cut-off device according to claim 5 in which the damping member is carried by a member formed with a shank slidable in a bore in a fixed body, adjustment of the position of the shank in the bore being provided for by a screw member which has portions with different screw threads engaging respectively in the shank and in a fixed member.

7. A cut-off device according to claim 1 in which the damping member is carried by a reciprocating ledger forming part of the cut-off device so as to contact the knife while it is performing each cut.

8. A cut-off device according to claim 7 in which the damping member constitutes a sleeve which forms part of the ledger and through which the rod passes during use.

9. A cut-off device according to claim 1 in which the clamping member is of a plastic material.

10. A cut-off device according to claim 1 in which the damping member is of wood.

11. A cut-off device according to claim 6 in which the damping member comprises a plastic material.

12. A cut-off device according to claim 6 in which the damping member comprises wood.

13 A cut-off device for a continuous rod-making machine, comprising support means for supporting the rod during cutting; a rotary cutting device comprising a rotary body carrying a knife which extends substantially radially with respect to the axis of rotation of the body and has an outer cutting edge which extends progressively further from the axis of rotation of the body and towards the trailing substantially radial edge of the knife; at least one grinding member lying in the path of the knife for engaging and sharpening the cutting edge of the knife; and a damping member lying in the path of the knife, between the grinding member and the support means, for contacting the knife to damp vibrations of the knife.

14. A cut-off device according to claim 13 in which the knife is mounted on the rotary body at a predetermined angle of inclination to a plane normal to the axis of rotation of the rotary body so as to form substantially part of a helix on the rotary body, and in which the axis of rotation of the body is inclined to the rod so that the knife is normal to the rod during cutting.

15. A cut-off device according to claim 13 in which the clamping member extends along a substantial arc about the axis of the rotary body.

16. A cut-off device according to claim 13 in which the damping member is fixed in position and contacts substantially only the trailing edge of the knife.

17. A cut-off device according to claim 13 wherein said damping member is mounted on said support means.

Claims

1. A cut-off device for a continuous rod making machine, comprising a knife which forms part of a helix on a rotary member rotating about a fixed axis and at least one damping member which is positioned at the downstream side of the knife, in relation to the direction of movement of the rod, and contacts the trailing edge of the knife at least in the event of the knive vibrating at or above a predetermined amplitude, so as to damp vibrations of the knife.

3. A cut-off device according to claim 2 in which there are two grinders which act successively on the opposite sides of the knife, and in which there are two damping members which respectively contact the knife to damp vibration after the knife passes each grinder.

9. A cut-off device according to claim 1 in which the damping member is of a plastic material.

12. A cut-off device according to claim 6 in which the damping member comprises wood. 13 A cut-off device for a continuous rod-making machine, comprising support means for supporting the rod during cutting; a rotary cutting device comprising a rotary body carrying a knife which extends substantially radially with respect to the axis of rotation of the body and has an outer cutting edge which extends progressively further from the axis of rotation of the body and towards the trailing substantially radial edge of the knife; at least one grinding member lying in the path of the knife for engaging and sharpening the cutting edge of the knife; and a damping member lying in the path of the knife, between the grinding member and the support means, for contacting the knife to damp vibrations of the knife.

15. A cut-off device according to claim 13 in which the damping member extends along a substantial arc about the axis of the rotary body.