GB1593337A - Device comprising brakes acting on unwinding web reels - Google Patents

Description

(54) A DEVICE COMPRISING BRAKES ACTING ON UNWINDING WEB REELS (71) We, FOCKE & PFUHL, of Siemensstrasse 10, D-2810 Verden, Federal Republic of Germany, a German Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device of the kind (herein called "the kind defined") comprising reels holding wound webs of packaging or other material, brakes for retarding the rotation of the reels during unwinding of the webs, and brake-control means for controlling the brakes automatically in response to variations in the tension in an unwound portion of a web which is unwinding from one of the said reels.

In packaging machines such as are used e.g. in cigarette-making factories, the packaging material, such as paper, foils or films or the like, is conventionally processed in the form of webs unreeled from reels. The webs are often supplied to the packaging machines from device of the kind defined.

For many reasons there are bound to be interruptions of the production flow when a packing machine is in operation. When there is an interruption in the unreeling of a web from the associated reel, the relatively heavy mass of the reel continues to move for some little time before finally stopping, with the result that excess web is unreeled. In a device of the kind defined the brakes serve for braking a reel rapidly when the said tension decreases as a result of an interruption.

In one known device of the kind defined a separate system of web-deflecting rollers is associated with each reel, and in each system two such rollers are disposed on a pivoting actuating arm which transmits variations of web tension in the form of pivoting movements to a double-armed brake lever so that a brake shoe thereon is pressed by a spring on to a brake drum of the reel concerned in the event of a considerable decrease in web tension. The construction of such a device with separate systems is complicated and therefore expensive and prone to faults.

The invention is intended to provide a device of the kind defined which can be of simple construction and trouble-free in use.

According to the invention a device of the kind defined is characterised in that the said brake-control means comprises a pivotallymounted rocker, a web-deflecting roller mounted on the rocker, a biassing spring loading the rocker in one direction of rotation, and common transmissions means for transmitting motion from the rocker to the brakes, all in combination whereby when the device is in use the said webdeflecting roller is lapped by a loop of the said unwound portion of the web, the tension in which tends to turn the rocker in the direction of rotation opposite to that promoted by the said biassing spring, and in response to the said variations in the said tension the reels are subjected to braking in unison.

The transmission means may include a cam, and there may be brake shoes to co-operate with respective brake drums.

Alternatively there may be a brake band common to the brake drums, and the transmission means may be in the form of a simple spring.

How the invention may be put into practice is described in greater detail below with reference to the accompanying drawings, in which: Figure I is a view in diagrammatic side elevation showing part of a first device embodying the invention, and Figure 2 is a diagrammatic side view of a second device embodying the invention.

The illustrated devices are supplying webs 10 or 11 of packaging material to packaging machines. The web 10 is wound on a reel 12, and the web 11 is wound on a reel 13. One of the webs 10 or 11 at a time is unreeled from whichever reel is in the operative position.

Figure 1 shows brakes 14 and 15 each comprising a two-armed brake arm 16 pivotable around a respective pivot bearing 17.

Each arm 16 has a brake shoe 18 to co-operate with a respective brake drum 19 of the reel 12 or 13.

The brake arms 16 are moved by motion transmitted from a rocker 20 mounted on a pivot bearing 33 and carrying a webdeflecting roller 21. The roller 21 is "floatingly" mounted and is lapped by a loop of the web 10 or 11; it is preceded by guide roller 22 and followed by another guide roller 23. The rollers 22 and 23 rotate about fixed axes. The web 10 or 11 laps the rollers 21, 22, 23 in the manner indicated.

The rocker 20 of the device of Figure 1 moves in response to variations in the tensions of the web 10 or 11, and carries a cam 24 followed by a cam-follower roller 26 running on a track 25 of the cam 24. The roller 26 is connected to both the brake arms 16, which are loaded by respective return springs 27 to ensure reliable engagement between the roller 26 and the track 25. The rocker 20 is biassed by a biassing spring 28 opposing the forces from the web 10 or 11.

When the tension of the web 10 or 11 decreases, e.g. because the machine stops, the rocker 20 is pivoted, anti-clockwise as viewed in Figure 1, by the spring 28, to move the cam 24 so that the roller 26 runs on a zone of the track 25 allowing the brake arms 16 to pivot in a direction pressing each brake shoe 18 on to the respective drum 19; the braking force in this case is exerted by the return springs 27. When the tension of the web 10 or 11 returns to normal, the rocker 2() returns to the initial position illustrated. Thus due to the motions of the rocker 20 in response to variations in the tension of the web 10 or 11 the reels 12 and 13 are subjected to braking in unison.

ln the device shown in Figure 2 a brake band 29 engages both the brake drums 19 of the two reels 12 and 13. One end 30 of the band 29 is fixed to an anchorage. The other end 31 of the band 29 is connected to a compensating spring 32 which is connected to the rocker 2(). Consequently. in this device the movements of the rocker 20 vary the stressing of the compensating spring 32 which is connected directly to the brake band 29, so as to apply or release the brakes in unison.

In the device of Figure 2 the spring 28 biassing the rocker 2() is connected to a projecting arm 34 fixed to the rocker 20, which turns on the pivot bearing 33.

In each illustrated device a single actuating element in the form of a rocker operates all the brakes, and there is only one system of rollers 21, 22, 23.

WHAT WE CLAIM IS: 1. A device of the kind defined herein, characterised in that the said brake-control means comprises a pivotally-mounted rocker (20), a web-deflecting roller (21) mounted on the roller (20), a biassing spring (28) loading the rocker (20) in one direction of rotation, and common transmission means (24, 26; 32 for transmitting motion from the rocker 20) to the brakes, all in combination whereby when the device is in use the said web-deflecting roller (21) is lapped by a loop of the said unwound portion of the web (10, 11) the tension in which tends to turn the rocker (20) in the direction of rotation opposite to that promoted by the said biassing spring (28), and in response to the said variations in the said tension the reels (12, 13) are subjected to braking in unison.

2. A device according to Claim 1, comprising guide rollers (22, 23) which rotate about fixed axes and are lapped by the said unwound portion of the web (10, 11) and respectively guide the web (10, 11) into and out of the said loop.

3. A device according to Claim 1 or 2, wherein the transmission means include a cam (24) which is followed by a camfollower (26) for the operation of the brakes (14, 15).

4. A device according to Claim 3, wherein each of the brakes (14, 15) includes a pivoted brake arm (16) having one end operatively connected to the cam-follower (26).

5. A device according to Claims 1 or 2, wherein a brake band (29) is common to the reels (12, 13) and is operated by the rocker (20).

6. A device according to Claim 5, wherein the brake band (29) has one end (30) fixed to an anchorage and has its other end (31) connected to a compensating spring (32) which is connected to the rocker (20).

7. A device of the kind defined, constructed and arranged substantially as hereinbefore described with reference to and as schematically illustrated in Figure 1 or Figure 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. machines. The web 10 is wound on a reel 12, and the web 11 is wound on a reel 13. One of the webs 10 or 11 at a time is unreeled from whichever reel is in the operative position. Figure 1 shows brakes 14 and 15 each comprising a two-armed brake arm 16 pivotable around a respective pivot bearing 17. Each arm 16 has a brake shoe 18 to co-operate with a respective brake drum 19 of the reel 12 or 13. The brake arms 16 are moved by motion transmitted from a rocker 20 mounted on a pivot bearing 33 and carrying a webdeflecting roller 21. The roller 21 is "floatingly" mounted and is lapped by a loop of the web 10 or 11; it is preceded by guide roller 22 and followed by another guide roller 23. The rollers 22 and 23 rotate about fixed axes. The web 10 or 11 laps the rollers 21, 22, 23 in the manner indicated. The rocker 20 of the device of Figure 1 moves in response to variations in the tensions of the web 10 or 11, and carries a cam 24 followed by a cam-follower roller 26 running on a track 25 of the cam 24. The roller 26 is connected to both the brake arms 16, which are loaded by respective return springs 27 to ensure reliable engagement between the roller 26 and the track 25. The rocker 20 is biassed by a biassing spring 28 opposing the forces from the web 10 or 11. When the tension of the web 10 or 11 decreases, e.g. because the machine stops, the rocker 20 is pivoted, anti-clockwise as viewed in Figure 1, by the spring 28, to move the cam 24 so that the roller 26 runs on a zone of the track 25 allowing the brake arms 16 to pivot in a direction pressing each brake shoe 18 on to the respective drum 19; the braking force in this case is exerted by the return springs 27. When the tension of the web 10 or 11 returns to normal, the rocker 2() returns to the initial position illustrated. Thus due to the motions of the rocker 20 in response to variations in the tension of the web 10 or 11 the reels 12 and 13 are subjected to braking in unison. ln the device shown in Figure 2 a brake band 29 engages both the brake drums 19 of the two reels 12 and 13. One end 30 of the band 29 is fixed to an anchorage. The other end 31 of the band 29 is connected to a compensating spring 32 which is connected to the rocker 2(). Consequently. in this device the movements of the rocker 20 vary the stressing of the compensating spring 32 which is connected directly to the brake band 29, so as to apply or release the brakes in unison. In the device of Figure 2 the spring 28 biassing the rocker 2() is connected to a projecting arm 34 fixed to the rocker 20, which turns on the pivot bearing 33. In each illustrated device a single actuating element in the form of a rocker operates all the brakes, and there is only one system of rollers 21, 22, 23. WHAT WE CLAIM IS:

1. A device of the kind defined herein, characterised in that the said brake-control means comprises a pivotally-mounted rocker (20), a web-deflecting roller (21) mounted on the roller (20), a biassing spring (28) loading the rocker (20) in one direction of rotation, and common transmission means (24, 26; 32 for transmitting motion from the rocker 20) to the brakes, all in combination whereby when the device is in use the said web-deflecting roller (21) is lapped by a loop of the said unwound portion of the web (10, 11) the tension in which tends to turn the rocker (20) in the direction of rotation opposite to that promoted by the said biassing spring (28), and in response to the said variations in the said tension the reels (12, 13) are subjected to braking in unison.

2. A device according to Claim 1, comprising guide rollers (22, 23) which rotate about fixed axes and are lapped by the said unwound portion of the web (10, 11) and respectively guide the web (10, 11) into and out of the said loop.

3. A device according to Claim 1 or 2, wherein the transmission means include a cam (24) which is followed by a camfollower (26) for the operation of the brakes (14, 15).

4. A device according to Claim 3, wherein each of the brakes (14, 15) includes a pivoted brake arm (16) having one end operatively connected to the cam-follower (26).

5. A device according to Claims 1 or 2, wherein a brake band (29) is common to the reels (12, 13) and is operated by the rocker (20).

6. A device according to Claim 5, wherein the brake band (29) has one end (30) fixed to an anchorage and has its other end (31) connected to a compensating spring (32) which is connected to the rocker (20).

7. A device of the kind defined, constructed and arranged substantially as hereinbefore described with reference to and as schematically illustrated in Figure 1 or Figure 2 of the accompanying drawings.