Brake structure of a band reel

Abstract: The present invention provides a brake structure for braking a band reel (10) from which a band (B) is to be fed out. The brake structure is provided on a reel shaft (13) and the reel shaft is rotatable with the band reel. A brake arm (15) is provided on the reel shaft, the brake arm having a coil spring (16) and a band guide portion (18). The coil spring is provided at an end of the brake arm and one end of the coil spring is fastened to a fixing member (25). Upon application of a force to the guide portion of the brake arm by the band when it is fed out, the coil spring increases in diameter to form a clearance between an outer periphery of the reel shaft and an inner periphery of the coil spring to allow rotation of the reel shaft. Upon release of the force applied to the guide portion of the brake arm by the band when it is fed out, the inner periphery of the coil spring portion of the brake arm frictionally engages the outer periphery of the reel shaft, thereby preventing rotation of the reel shaft.

Description: The present invention relates to a brake structure of a band reel. More particularly, the invention relates to a brake structure of a band reel installed in a packing machine. In an automatic or semi-automatic banding packing machine, a band reel 1 having a long band B wound thereupon is provided in a packing machine body 2 as shown in Fig. 4. A tip of the band B led from the band reel 1 is fed to the packing machine body 2 side by the rotating force of a feed roller (not shown) or the like. On the other hand, a brake arm 3 is provided in the vicinity of the band reel 1 and the band B is fed to the packing machine body 2 side through a guide roller 3a of the brake arm 3. In such a packing machine, in the case in which, in one packing step, the band is completely fed from the band reel 1 and is to be then returned and tightened, the rotation of the band reel 1 should be stopped immediately. Otherwise, extra band is loosened so that a slack portion of the band hangs and twists, and thus entanglement may occur in the vicinity of the guide roller 3a. As a conventional method in which the rotation of the band reel 1 is stopped immediately after the band is completely fed, there have been known a method of pushing a pad against the side surface of the band reel 1 to stop the rotation by means of the pad. There have been also known a method of stopping the rotation of the band reel 1 by pushing a V-shaped brake belt 5 shown in Fig. 5, for example, against a brake pulley during braking, the brake pulley being attached to the peripheral surface of a reel shaft 4 pivotally supporting the band reel 1. In the method using the brake pad, however, the force for stopping the rotation is small and the band reel 1 is rotated for a while even if a stop operation is started. In the method using the brake belt 5, moreover, there has been a problem in that the force for stopping the rotation is great but the braking is not stabilized if the intrusion of the V belt is poor. EP 0403878 discloses a braking structure for an electrical cable winding device. The braking structure comprises a coil spring acting on a braking surface attached to the cable drum, wherein the coil spring normally grips the braking surface to prevent rotation of the cable drum. When the cable is pulled, a series of levers and unlocking elements are operated to expand the diameter of the coil spring, thus releasing the spring from engagement with the braking surface and allowing the cable to be withdrawn. When the cable ceases to be pulled, the spring once again prevents rotation of the cable drum. In consideration of the above-mentioned circumstances, it is an object of the present invention to provide a brake structure of a band reel in which braking effects can be obtained reliably and responsiveness is excellent. US 6079658 discloses a brake structure for braking a band reel from which a band is to be fed out, the brake structure being provided on a reel shaft and the reel shaft being rotatable with the band reel, wherein a brake arm is provided on the reel shaft, the brake arm having a coil spring, the coil spring being provided at an end of the brake arm and one end of the coil spring being fastened to a fixing member. The present invention is characterised over US 6079658 in that the brake arm has a band guide portion wherein, upon application of a force to the guide portion of the brake arm by the band when it is fed out, the coil spring increases in diameter to form a clearance between an outer periphery of the reel shaft and an inner periphery of the coil spring to allow rotation of the reel shaft, and wherein, upon release of the force applied to the guide portion of the brake arm by the band when it is fed out, the inner periphery of the coil spring portion of the brake arm frictionally engages the outer periphery of the reel shaft, thereby preventing rotation of the reel shaft. Preferably the band guide portion is provided at the end of the brake arm distal from the coil spring. It is further preferred that the guide portion is a ring member through which the band is passed. According to the present invention having such a structure, when the band feeding operation is ended, the rotation of the band reel can be stopped, and furthermore, the structure can be simplified. The brake structure according to the present invention is preferably installed in a packing machine. When the brake structure of the band reel is installed in a packing machine, if the force for leading out the band through the band feeding roller is released when the band is completely fed from the band reel, the diameter of the coil spring portion is reduced so that the rotation of the reel shaft can be stopped. Accordingly, the slack portion of the band can be prevented from hanging. In such a structure, moreover, only the coil spring is used. Therefore, the structure can be simplified and the responsiveness can also be enhanced. A preferred embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Fig. 1 is a sectional view showing a band reel comprising a brake structure according to an embodiment of the present invention, Fig. 2 is a front view showing the band reel, Fig. 3 is an exploded perspective view showing the brake structure according to the embodiment, Fig. 4 is a perspective view showing a packing machine comprising a conventional band reel, and Fig. 5 is an exploded perspective view showing a brake structure constituted in the conventional band reel. Fig. 1 is a view showing a band reel comprising a brake structure according to the embodiment of the present invention. In a band reel 10, a band housing portion for winding a band B is formed by an inner flange 11, an outer flange 12 and a reel shaft 13. A male screw 13a is formed on the tip of the reel shaft 13 and a female screw 14a of a nut handle 14 is screwed into the male screw 13a. On the other hand, a collar 19 is provided at one end of the reel shaft 13 which is protruded from the inner flange 11 as also shown in Fig. 3. The collar 19 is rotated integrally with the reel shaft 13 through a screw member 20 inserted between the collar 19 and the reel shaft 13. The base end side of a brake arm 15 according to the present embodiment is provided on the outer peripheral side of the collar 19. The brake arm 15 has a coil spring portion 16 provided on the base end side and a dogleg-shaped arm portion 17 extended on the other end side. An end 16a of the coil spring portion 16 is fixed unrotatably to a reel bearing case 25 fastened to a device frame or the like.Moreover, a band passing ring portion 18 for guiding the band B is provided on the tip of the arm portion 17. The tip of the band B is caused to pass through the ring portion 18 and is then fed toward the packing machine body side. In such a band reel 10, if the tip of the band B is pulled from the packing machine body side in a direction of an arrow C as shown in Fig. 2, the band B is led out. While the band B is led out, that is, the band feeding means feeds the band B toward the packing machine body side,the force in the direction of the arrow D acts on the brake arm 15 in Fig. 3. Accordingly, the diameter of the coil spring portion 16 is enlarged. Therefore, when the band B is fed toward the packing machine body side, a gap between the coil spring portion 16 and the collar 19 fixed to the reel shaft 13 is increased. Consequently, the rotation of the reel shaft 13 cannot be prevented. On the other hand, when the band B is completely fed, the force in the direction of the arrow D which pulls the brake arm 15 is released, and conversely, force in a direction of an arrow E acts on the coil spring portion 16 by the force for causing the coil spring portion 16 to return to an original position as shown in Fig 2 and 3. When the force thus acts in the direction of the arrow E, the coil spring portion 16 comes into contact with the peripheral surface of the collar 19 by pressure so that the collar 19 is brought into an unrotation state and the brake arm 15 is moved from a position shown in a broken line to a position shown in a solid line in Fig. 2. Accordingly, if the rotation of the reel shaft 13 is stopped, the slack portion of the band is not led out any more. Consequently, the band can be prevented from hanging. In the case of an automatic machine, the tightening and returning steps are then started. The returned band is fed into a pool box of the packing machine body. While the embodiment of the present invention has been described above, the present invention is not restricted to the embodiment. The present invention can be applied to an automatic machine and a semi-automatic machine. Numerous modifications and alternative embodiments of the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and/or function may be varied substantially without departing from the invention and all modifications which come within the scope of the appended claims are reserved.

Claims: A brake structure for braking a band reel (10) from which a band (B) is to be fed out, the brake structure being provided on a reel shaft (13) and the reel shaft being rotatable with the band reel, wherein a brake arm (15) is provided on the reel shaft, the brake arm having a coil spring (16), the coil spring being provided at an end of the brake arm and one end of the coil spring being fastened to a fixing member (25), characterised in that the brake arm (15) has a band guide portion (18) wherein, upon application of a force to the guide portion of the brake arm by the band (B) when it is fed out, the coil spring (16) increases in diameter to form a clearance between an outer periphery of the reel shaft (13) and an inner periphery of the coil spring to allow rotation of the reel shaft, and wherein, upon release of the force applied to the guide portion of the brake arm by the band when it is fed out, the inner periphery of the coil spring portion of the brake arm frictionally engages the outer periphery of the reel shaft, thereby preventing rotation of the reel shaft. A brake structure as claimed in claim 1, wherein the band guide portion (18) is provided at an end of the brake arm (15) distal from the coil spring (16). A brake structure as claimed in claim 1 or 2, wherein the guide portion (18) is a ring member through which the band (B) is passed. A brake structure as claimed in claim 1, 2 or 3 installed in a packing machine.

Inventors: AIZAWA YOSHIKATSU, ENDA KENICHI, MEGURO TADASHI, SHIBAZAKI TOKIO, AIZAWA, YOSHIKATSU, ENDA, KENICHI, MEGURO, TADASHI, SHIBAZAKI, TOKIO, Aizawa, Yoshikatsu, c/o Strapack Corporation, Enda, Kenichi, c/o Strapack Corporation, Meguro, Tadashi, c/o Strapack Corporation, Shibazaki, Tokio, c/o Strapack Corporation
Applicants: STRAPACK CORP, STRAPACK CORPORATION
Application year: 2001
Main classification: B65H59
IPC codes: B65B13, B65H59, B65H77