Patent GB-747242-A (GB)
Title: Improvements in loose-leaf bindings
IPC: B42F3/00
Filed: 1954-06-17
Abstract: 747,242. Loose leaf binders. VALLA, D. June 17, 1954 [June 27, 1953; May 31, 1954], No. 17788/54. Class 146(1) A binding for loose leaves comprises a coil with helical, interrupted turns of metallic wire in which the turns 42, as a-b, c-d are connected by axial portions 43, 41 as b-c, d-e aligned with two adjacent spaced-apart generatrices of the cylinder which the coil defines, and constituting the lips of a slot 45. the axial portions b-c, d-e between adjacent helical turns being opposite one another whereby the binding allows leaves 46 perforated at 47 at a pitch corresponding to that of the helical coil to jump over the slot 45 and make substantially two turns about the binding before striking the axial portions. As shown in Fig. 6, a single coil is formed into end turns 50 extended beyond the slot 45 to form lateral guards for the sheets, each turn 50 also comprising a radial part 51 and an axial part 52 inserted in a hole in a strut 53 extending along the axis of the coil. To give the coil rigidity, the turns 42 are initially formed slightly convergent and the strut 53 is of such length as to extend the coil so that the turns 42 are parallel. The slot 45 may be formed very narrow to prevent sheets becoming unbound, or the slot may be closed by a locking bar having a central part to be pushed in the slot or, as shown in Fig. 9, a locking bar 56 may be used, the bar 56 being, in section, in the shape of a C with the edges 57, 58 notched at 59. The notches 59 are spaced apart by the distance of the pitch of the coil and the distance between the edges 57, 58 is slightly less than the width of the slot plus the two thicknesses of wire, so that the parts 43, 44 of the coil 41 are engaged under the wing portions by narrowing the slot 45. As shown in Fig. 4, two half-coils 9, 10 are used having slots 7, 8 which may be turned into the same plane for removal or insertion of sheets 29 into slots 30. The coils 9, 10 are guided between sector guides 5, 6 coaxial therewith and covering about one-third of the coils. The inside guide 5 has helical protruberances and indentations 12 of the same pitch as the coils 9, 10 so as to form channels 14 in which the coils are guided. The guides 5, 6 are secured together as by gluing or soldering, and the inner guide 5 has a sunken helical edge 17 to prevent deformation of the first turn, and the outer guide 6 is terminated by hollow cylindrical parts 19 having helical inner edges 20 to allow rotation of the sheets, the parts 19 housing the helically wound ends 11 of the coils 9, 10. The half coils 9, 10 are brought into slots 7, 8 in alignment by rotation in opposite directions and this is effected by operating buttons 22 comprising hollow cylinders fitting into the end parts 19, one end of the buttons 22 having a milled flange 23. Each button has an internal groove terminating in a radial hole 25 in the flange 23 and a helical slot 26 having two axial returns 27, 28. In assembly, the buttons 22 are pushed into the parts 19 and the end of the coil, which is turned outwardly, is guided in the groove up to the hole 25 where it is engaged. A small tongue 21 is cut from the outer edge of the parts 19 and this is then turned up into the slot 26 to prevent removal and limit rotation of the button. In a further construction, the inner guide 5 is dispensed with and the outer guide has a slightly narrower diameter than its end parts 19 and is formed with rims to supply rigidity. Portions of the guide are bent up and at right angles to form channels for the coils. Specifications 422,409, 447,231, 661,062 and 687,016 are referred to.