Patent GB-718149-A (GB)
Title: Improvements in and relating to surface grinding machines
IPC: B24B27/00
Filed: 1952-06-03
Abstract: 718,149. Surface grinder. SADLER, T., [trading as SADLER, SONS, & CO., T.]. June 1, 1953, [June 3, 1952.] No. 13972/52. Class 60. A surface grinding machine comprises a vertical support column, a sleeve axially adjustable upon the column, and a unit which consists of a tubular boss which is rotationally adjustable on the sleeve, radial arms projecting rigidly in diametrically opposite directions from the tubular boss, a grinding head and an electric motor therefor carried respectively by the arms, the motor and head counterbalancing one another. A vertical support column 2 secured to base plate 1 houses a coarse lead screw 5, operated by handle 12, engaging a nut 14; a radial spigot 15, secured to the nut by screws (through one of which passes an oiler 16), extends through a slot 13 in the column and engages a sleeve 17 slidably mounted on the column. Two diametrically opposite radial arms 18, 19 are united at the centre by a tubular boss 20 which rotationally fits over the sleeve 17. The electric drive motor M is adjustably secured to the underside of the arm 18; the base plate 1 stops short of the motor which projects below the base plate. The motor drives through interchangeable pulley 33 and V-belt 32 a pulley 31 secured to the upper end of a spindle 27 running in roller bearings in the arm 19 and having secured to its lower end a cup grinding wheel 73. The pulley 31 houses a rotational coupling 38 which connects the spindle 27 to a fine adjustment lead screw 39 supported by an overhanging secondary arm 40 rising from the arm 19; a boss 41 on the arm 40 provides a vertical bearing for a bearing spindle extension 42 of the screw, this spindle having a flange 43 bearing against the underside of the boss. To the top end of the spindle 42 is secured an operating wheel 44 co-operating with a scale 45. The fine lead screw engages a threaded coupling sleeve 46, the lower end of which carries a ball bearing 47, the inner race 48 of which fits over a shouldered portion of the top end of the spindle 27 and is held in position by a fixing plate 49 screwed on the threaded end of the spindle 27. The outer race 51 is held in a recess in the lower end of sleeve 46 by a plate 52. A pin 54 projecting from the arm 40 engages a slot 55 in the sleeve 46 to restrain it from rotation. The end of the fine adjustment screw carries a stop plate 56 which limits the downward movement of the sleeve 46. A metal dust-excluding housing 57 covers the belt drive, being seated at its ends upon upstanding extensions 58, 59 of the radial arms 18, 19 with a joint 60 which springs over the boss 41 and a sealing gland 61 at the main support column 2; a belt tensioner may be carried by the cover. A dust-excluding bellows 62 connects the sleeve 17 with the base flange of the column 2. Dust is extracted through duct 63 in the base plate. The fine adjustment spindle 42 has an axial hole 64 terminating at the operating knob 44 in an inlet nipple 65, the lower end of the hole opening to a recess 66 in the top end of the spindle 27; a radial channel 67 leads from the recess 66 through the fixing plate 49 to discharge over the bearing 47. Oil or coolant can be passed through the channels. Means for starting and stopping the electric motor M may be embodied in a handle 77 for angularly traversing the head about the support column 2; the radial support arm for the head may have a radial extension in the form of a loop-shape handle which is movably mounted and connected to a starting switch, or the handle may have a switch-operating member which is rendered operative when the handle is gripped by the user. Generally the unit is adjusted angularly about the column 2, using the handle 77, so that the grinding head will traverse the work which is held stationary on the base plate 1 by a vice, chuck, e.g. magnetic, clamps or holding-down bolts. Provision may be made for locking the head and traversing the work; a retractable pin 78 loaded by spring 79 is carried in a housing 80 screwed into a tapped hole in the boss 20 so that the nose 81 of the pin engages in a recess 82 in the sleeve 17. The grinding spindle may be arranged horizontally; the vertical and rotational adjustments may be power operated.