Patent GB-860084-A (GB)
Title: Grinder with oscillating head
Inventor: BASS MILES M
IPC: B24B3/36
Filed: 1959-10-23
Abstract: 860,084. Grinding. HAMMOND MACHINERY BUILDERS Inc. Oct. 23, 1959, No. 36067/59. Class 60. A grinding machine comprises a wheel 11, Fig. 2, mounted on a shaft 12, a bracket 13 mounted on the machine frame 10 for oscillation or reciprocation transversely of the axis of rotation of the shaft, a work-supporting table 14, Fig. 3, in front of the wheel 11 movable toward and away therefrom, a first motor 17 drivingly connected to the shaft 12 and a second motor 29 connected by a manually adjustable linkage 18, 21, 24, Fig. 6 to the bracket 13 whereby the bracket and the shaft 12 may be oscillated whilst the shaft is rotating, to an adjustable extent. The bracket 13 is pivotally supported by a bearing assembly on a platform 15 secured to the frame 10, oscillation being effected by rocking the lever 18 about a fixed pivot 116, Fig. 2, the lower end being slotted and engaged by a roller 22 on a shaft 26 rotatable at a controllable speed by a pulley 25, belt-driven from. a speed-reducer 28 which is itself driven by the motor 29. The amplitude of oscillation is controlled by the variable eccentricity of the roller 22 with respect to the axis of rotation of the pulley 25, the adjusting means being operable by a handle 23 through the mechanism 24 shown in Fig. 6. The motor 17 is mounted on a pivoted support 109, an arm 112 extending therefrom and carrying a pin 113 which engages a slot in a pivoted vertical arm 115 ; as the motor 17 is suspended by its shaft-driving belt 16 it is free to move during the arcuate movements of the shaft 12, but downward movement of the support 109 is limited, in the event of belt breakage, by the pin 113. The forward end of the platform 15 is provided with ways 35, Fig. 3, which slidably support the table base 36, movement towards or away from the wheel 11 being manually effected by a hand-wheel and a shaft 37 screwed at its inner end to engage a back-lash eliminating split-nut secured to the frame. Table support members 47, 48, Fig. 6, extend upward from the base adjacent its lateral edges within a protective hood 46, the members having arcuate upper surfaces 49 which support correspondingly shaped brackets 52, 53 secured to the underside of the table 14. A pair of posts 56, 57 extend downwardly, through the brackets 52, 53 and slots in the arcuate members, the port of one member having means operable by a handle at the front of the machine for effecting the tilting of the table 14 about a horizontal axis in the plane of the table and adjacent the annular abrasive surface 104 of the wheel 11. Springs 61, 61a maintain contact between the arcuate surfaces of the brackets and the support members 47, 48. Side plates 55 are secured to, and extend downwardly beyond, the sides of these brackets to exclude dirt. The table 14, which may include a plurality of wear plates 77, is recessed at the rearward edge to receive the grinding wheel, the portions on opposite lateral sides of the recess 78 having wear plates 79, 80, Fig. 3, which are movable to allow for the variation of the sweep of the grinding wheel during its oscillatory, wear distributing, motion across the work. The extensions 79, 80 of the work-supporting surface enable the grinding of a reverse angle on a cutting tool 138, as shown in Fig. 8. A peripheral wheel guard 103, Fig. 3, may be moved concentrically around the wheel 11 to raise one end of the guard sufficiently above the table level to clear the tool. The guard 103 is carried by a sleeve 100, Fig. 8, around the forward bearing of the shaft 12 ; a flange 90 on the sleeve extends beyond the wheel periphery to prevent accidental contact between the wheel and table when the wheel is oscillating and the guard 103 is removed from or re-positioned on the sleeve 100. A tube 105, Fig. 3, for directing cooling or grinding fluid supplied by a pump 136, Fig. 2, to the centre of the wheel is supported by a forward extension of the guard 103, the fluid being returned for re-circulation by conventional means after collection in the hood 46. A flexible flanged seal closes the arcuate opening in the casing 97 within which the wheel shaft 12 and its mounting 13 oscillate. The arc of movement is less than the radial width of the abrasive face of the wheel. Fig. 12 shows an alternative mechanism for oscillating the grinding wheel support 13. A pulley 152, belt-driven by a speed-reducer 154, rotates a crank carrying a roller 145 which engages a slot 144 in a rocking lever 143 the opposite end of which is pinjointed to an integral arm 142 projecting at a right-angle from the shaft rocking support 13. Variation of the amplitude of oscillation is effected by a hand wheel 165 which may rotate a screwed shaft 163 to shift the fulcrum 158 about which the lever 143 is rocked towards or away from its connection to the arm 142 ; when the fulcrum and pin-joint are co-incident no motion is transmitted to the mounting 13. Figs. 15-18, (not shown,) relate to an alternative form of horse-shoe shaped wheel guard which is rigidly fixed to its mount, the halves of the guard being separately capable of swinging upwards to clear a tool when in position for grinding a reverse face, as shown in Fig. 8. The tool may be held manually or mechanically on the table 14 during this or other grinding operations.