GB626237A - Improvements in or relating to machines for grinding grass and like cutters - Google Patents

Abstract

626,237. Grinding lawn-mower blades &c. BLAKESLEY, L. F. Feb. 11, 1947, No. 3963. [Class 60] In a grinding machine adapted to perform the dual purposes of grinding the spiral blades of rotary cutters, e.g. of lawnmowers, and surface grinding, the work carriage is provided, removably, either with axially aligned bearings or/and tapered centres or with an attachment for holding work, such as a bottom or ledger blade, in a horizontal or substantially horizontal plane to be surface ground, and the grinding wheel spindle is adapted to be turned from a position above and parallel to the common axis of the said bearings or/and tapered centres to a position in which it is at right angles to the said axis. The grinding wheel 14, driven by electric motor 15 through belt 16, is mounted on a carriage 12 vertically adjustable, by screw 18 and handwheel 17, on a member 9 having spaced collars 8 rotatable about a column 7 secured to a beam 6 of the machine frame. Locking handles 10 secure the member 9 in adjusted position. The work carriage comprises a bar 19 movable longitudinally relative to a bar 4 secured to the machine frame; the bar 19 having spaced bridge pieces 20 engaging the top of the bar 4 and steadying plates 21 engaging the front of the bar 4, strips 22 of brass being adjustable by screws 23. The lower edge of the bar 19 is toothed to provide a rack 24 meshing with a pinion 25 operated by a handwheel 29. Brackets 30 are secured to the bar 19, each bracket being surmounted by a ring 31 having journal-supporting rollers 32 or balls and a bearing pad 33 adjustable by a screw 34. Each bracket 30 also has an upstanding extension 42 carrying an axially adjustable tapered centre 43. The brackets 30 are adjustably secured to the bar 19 by screws 39 and locking nuts 40. The cutting cylinder 45 being ground is mounted either by means of its journals on the rollers 32 or by means of the centres 43. The back of the blade being ground is engaged by a finger 48 having a shank 49 adjustable, by means of a handle 50, within a carrier 51 provided at the free end of an arm 52 pivoted at 53 so that it can be swung to inoperative position. The axis of the grinding wheel is adjusted to be parallel to the axis of the work. For surface grinding, the brackets 30 are replaced by an attachment for holding work such as a bottom or ledger blade in a horizontal or substantially horizontal plane. The grinding wheel is then set with its axis at right angles to the length of the bar 19. The attachment comprises a U-shaped frame 54 having bosses 55 for a rod 56 on the ends of which are adjustably mounted clamps 57 for the ends of the blade. The rod 56 also has adjustable blocks 59 with aligned holes 60 to receive the pintles, when the blade is provided with these. The frame 54 is spigot mounted at 61 on a carriage 62 mounted on a slide 63, transverse adjustment being effected by a screw 64. The attachment also has a bar 65 carrying at its ends screws 66 contacting the top of bar 19 for adjustment purposes. The attachment is secured to the bar 19 by screws 67.