Patent GB-282290-A (GB)
Title: Saw filing machines
IPC: B23D63/10
Filed: 1927-06-07
Abstract: 282,290. Collier, F. E. June 7, 1927. Saws, sharpening. - In a saw-sharpening machine employing a reciprocating file a feeding dog is adapted to engage the last filed tooth to position it at a predetermined distance from the position in which it was filed. In this way the irregularities of old teeth are not repeated and new teeth may be cut .n a saw by filing the first tooth and then putting the feeding mechanism into operation to feed from this tooth initially. The file d is carried in frame 48. Fig. 3, attached to a cross-head 47 which is reciprocated in horizontal guides 46 by an adjustable-throw crank pin 58 engaging a vertical slot 75 in the cross-head, the latter being given a vertical movement to and from the saw at each end of its stroke by a cam 70 engaging lugs 72 ,73 attached to the guides 46. Springs 104 tend to keep the cross-head in its lower position. The vertical movement is guided by rods 45 carried by a vertical bracket 38 pivoted at 40 in the same vertical plane as the saw a and adjustable about the pivot, locking in any angular position being performed by bolts 43 engaging concentric actuate guides 44 on the machine frame. The file is adjustably attached to its frame by two sockets 55. Figs. 3, 10, and 11 shaped internally to receive the end and tang of the file respectively and formed double-ended to receive files of different sizes. The sockets are received in bushes 53 having extensions 49 entering bosses 50 in the ends of the frame, the extensions being vertically adjustable by springs and nuts 51 and locked by screws 56. The sockets 55 are rotatably adjustable in the bushes 53, the latter being split for clamping. The shaft 58 which carries the cam and crank for operating the file is rotated through gearing 59 and a clutch from a ny-wheel 64, the latter being driven by a hand crank or a belt connecting with an electric motor 66. The front plate 22 of the machine frame is provided with a jaw 31, Figs. 3 and 16, and carries a pivot 28 for a second jaw 30, the jaws being adjustable by a nut 36 engaging a screwed bolt 33 passing therethrough to guide the saw a between them. If a circular saw is to be treated a conical boss 99 is mounted on a bolt 32 screwed into the bolt 33 and the. eye of the saw is gripped between the boss 99 and a channel bar 98 vertically adjustable on the plate 22 by a screw 100 and nut 101, the jaws being slotted at 25 and 34 to allow adjustment. When filing a hand saw, bars 87, Figs. 3 and 12, are secured to the sides of the saw by bolts and slide between lower and upper angle bars 89, 91 which guide the saw horizontally while the jaws 30, 31 guide it laterally and engage it with sufficient friction to prevent over-feeding. The saw is fed by a pawl 83, Fig. 12, pivoted to a bell crank lever 76 having at its other end an adjustable screw 77 engaging a bearing plate 78 attached to the file frame 48, the action being such that when the frame is raised at the end of a filing stroke the lever is oscillated and the saw fed. A spring 82 tends to retract the pawl and a screw stop 86 limits its backward movement. The feeding mechanism is duplicated on each side of the file frame for feeding in either direction, each pawl being held in the operative or inoperative position by a spring plunger 85 engaging its square end. To cause the pawl to engage the tooth which was last filed a cam 92, adjustably secured at 95 to the plate 22, supports a pin 93 on the pawl and prevents it from engaging the saw until the correct tooth is reached. Adjustment of the cam 92 may also vary the pitch of the teeth cut. When filing a band saw the latter is supported by a series of bifurcated lugs 110, Fig. 19, on a. carrier 108 pivoted at 109 to a plate secured to the plate 22 and carrying a bolt which passes through an arcuate slot 112 in the carrier for locking in any inclined position to suit the under-cut of the. sawteeth. The pivot of the lever 76 is moved to a hole 103, Fig. 12, when the saw is raised at the right hand side of the machine.