Patent GB-1496104-A (GB)
Title: Bandsaw machine
IPC: B23D53/04
Filed: 1976-10-04
Abstract: 1496104 Bandsaws GES FUR SCHNEIDTECHNIK mbH 4 Oct 1976 [11 Oct 1975] 41140/76 Heading B5L A bandsaw machine comprises a machine stand 1 having a table 1a furnished with jaws 9, 10 for clamping a workpiece thereon, and a sawhead 3 which has at least two guide wheels 4, 5 over which an endless saw band 6 runs, the head being pivoted to the stand for downward feed of the saw band, the running plane of the guide wheels being inclined to the plane of downward feed of the saw band. The head has saw guides 7, 8 for twisting the working portion of the saw band into the feed and cutting plane, each guide having two plates 23, 35 between which the saw band is received and which have, at least at their entry and exit ends, hardened surfaces 26, 27, 28, 29 forming sliding guides for the saw band. The sliding guide 29 of each guide on the side of the guide facing the guide wheel and nearest to the adjacent guide wheel and beside the toothing of the saw band is prolonged in the direction towards the guide wheel and shaped in accordance to the deflection of the saw band between the guide and guide wheel. The saw head is mounted on a pivot 2 on the machine stand 1 and is raised and lowered by an hydraulic cylinder unit 22 controlled by a circuit such as described in Specification 1,394,467. The guide wheels 4, 5, over which the saw band 6 runs, are inclined to the plane of movement of the saw head, the working portion of the band being twisted into the plane by the guides 7, 8 for cutting of a workpiece held between a fixed jaw 9 and a movable jaw 10. The guide 7 adjacent the fixed jaw 9 is fixed to the head 3 whereas the guide 8 adjacent the movable jaw 10 is mounted on a carriage 11 guided by rollers 12 on a rail 13 on the head whereby the distance between the guides is adjustable to correspond with the distance between the jaws. A further guide 14 for the saw band is guided by rollers 17 on a further carriage 16, in turn, guided by rollers 15 on the beam. A line 18 is guided over a pulley 21 on the carriage 16 and connected at its ends to the carriage 11 and a fixed point 19 on the head so that movement of the carriage 11 to position the guide 8 causes a corresponding movement of half the distance of the carriage 16 and guide 14 which is thereby maintained midway between the guides 7, 8. Each guide 7, 8 consists of two plates 23, 25, one each side of the saw band. The plate 23 of the guide 7 on the side of the saw band on which the guide wheels lie has sliding surfaces 26, 27, 28, 29 of wear resistant material which engage the saw band adjacent its back and close to its teeth. The surfaces 26, 27, 28 and the left hand part of the surface 29 lie in a common plane, the right hand projection 30 of surface 29 having a surface which twists in conformation of the twist of the band between the guide and its adjacent guide wheel. The plate 23 of the guide 8 is a mirror image of that for the guide 7. The plates may be so shaped that the twist of the band occurs along the longitudinal centre line of the band or nearer to the back of the band to increase the tension in the toothed part of the band. The plates 23 are secured by screws to carriers 34 fixed to the saw head, the plates 35 being urged towards the saw band by rockers 43 acted upon by adjustable springs 41. Each carrier has a further guide 38, 39 engaging the back of the saw band.