Patent GB-825325-A (GB)
Title: Improvements in or relating to automatic feed mechanism for grinding machines
IPC: B24B47/20
Filed: 1958-01-10
Abstract: 825,325. Grinding. GEAR GRINDING MACHINE CO. Jan. 10, 1958 [Jan. 15, 1957], No. 1074/58. Class 60. The position of a stop H, Figs. 1 and 2, for arresting the movement of a mechanism for feeding a grinding wheel into a workpiece, such as a gear wheel, is minutely adjustable to two arresting. positions to a high degree of accuracy and between which a second stop L2 normally removed from obstructing the feed mechanism can be moved. The feed mechanism described is similar to that in Specification 662,205 and comprises a rod E, Fig. 4, either manually-rotatable to feed the grinding wheel into the work, which is mounted on an arbor intermittently rotated by an indexing mechanism and movable axially relative to the grinding wheel, or axially-moved by the rotation of a shaft B on which is an eccentric B<SP>1</SP> engaged by a member C connected to the rod E by a pin C<SP>2</SP> and member D. The shaft B carries a pinion B<SP>2</SP> engaging a rack F which is formed at each end with pistons F<SP>1</SP>, F<SP>2</SP>, Fig. 1, slidable in cylinders G, G2 to which metered fluid under pressure may be supplied to provide a step-by-step movement of the rack. The extent of movement of the rack to the left is controlled by the stop H which is axiallyslidable in a housing A<SP>3</SP> and carries a roller H<SP>2</SP> engaging a cam J<SP>1</SP> slidable along a rod I. The cam is connected to the rod K, Fig. 5, of a piston K<SP>1</SP> which can be urged by fluid pressure, in one direction to abut a head K<SP>3</SP>, and in the other direction to abut a rod K<SP>5</SP> axially-adjustable by means of a nut K<SP>6</SP>, the position of the rod being determined by a scale K<SP>7</SP> and enabling the position of the stop H, when the piston K<SP>1</SP> abuts the rod K<SP>5</SP>, to be determined to an accuracy of 0À0001 inch. The extent of movement of the rack F to the right is normally unrestricted but, when it is desired to precede the final cut with a semi-finishing cut, the second adjustable stop L<SP>2</SP> carried on an arm L can be swung into axial alignment with an extension N on the rack F by the energisation of a solenoid O. In operation, the piston K<SP>1</SP> normally abuts the head K<SP>3</SP> to arrest movement of the rack at the completion of the rough grinding operation, the stop H thereafter being adjusted by an amount determined by the position of the rod K<SP>5</SP> after trueing of the grinding wheel for the finishing cut. When it is desired to take a semi-finishing cut prior to the finishing cut, the rod K<SP>5</SP> is adjusted to space the two positions of the stop H a distance apart equal to the sum of the semi and final finishing cuts. The piston K<SP>1</SP> is then urged against the stop rod K<SP>5</SP> and the solenoid O energized to bring the stop L<SP>2</SP> into alignment with the rod N so that it can be adjusted to a distance equal to the depth of the final cut from the rod N. The rack is then moved as far to the left as permitted by the stop L<SP>2</SP> and the semi-finishing cut taken. After final trueing of the wheel, the piston K<SP>1</SP> is moved into contact with the rod K5, the rack to the left to contact the stop H and the finishing cut taken.