Patent GB-1441559-A (GB)
Title: Machines and shut-off mechanisms for use thereon
IPC: B23Q17/20
Filed: 1974-11-23
Abstract: 1441559 Grinding J SUNNEN 23 Nov 1974 50833/74 Headings B3D and B3B A release or shut-off mechanism for use on a machine for operating on workpieces, the machine having pedal means to activate the machine and monitoring means responsive to a predetermined condition of the workpiece to terminate a machine operation, the mechanism comprising latching means adapted to be associated with the pedal means and including means movable to a latched condition when the pedal means are actuated, whereby the operating condition of the machine may be maintained independently of the pedal means, and delatching means operable to delatch the latching means when the predetermined condition is sensed by the monitoring means. As described, the mechanism is used on a honing machine 12 having a mandrel adapter 14 which rotates a honing tool having elements movable outwardly into engagement with a surface to be honed when a foot pedal (not shown) is depressed and moves a rod 16. The upper end of the rod is connected to a latching lever 20 which extends between spaced members 22, 24 and has a stud 26 for moving the member 22. The rod 16 also extends through a member 30 pivotally mounted on a arm 32 rockable about a shaft 34, the shaft, upon rotation by the pedal, setting up conditions in the machine necessary for the honing operation. Downward movement of the lever 20 when pulled by the rod 16 causes stud 26 to rock member 22 about a fixed pivot 42 and to thus move a latch member 44 mounted on a pivot 46 on member 22 to the right, the member having a hardened edge postion 50 which co-operates with a similar portion 52 on a second latch member 54. A spring 56 biases the latch member 44 in a clockwise direction to a position determined by a pin 62 wherein, when pressure is removed from the foot pedal, the positions 50, 52 of the latch members will engage. At the same time, a pair of latch members 66, 68 which are connected together by a pivot 70 are moved to an overcentre position, member 66 being mounted on a fixed pivot 42 and member 68 being pivotally connected to the arm 32 at pivot 72. An adjustable excentric stop 74 on member 66 engages a notch in member 68 to determine the over-centre position. A stud 82 on latch member 66 can be engaged by member 22 to unlatch the members to release arm 32 and stop the honing operation. Manual means may also release the latch members 66, 68 and consist of a knob 86 on a lever 88 mounted on a pivot 90 and movable against the pressure of a spring 98 to engage an L-shaped spring member 104 with the latch members 66, 68 adjacent the pivot 70. The delatching of the latching means when the monitoring means senses the predetermined condition is effected by a feed-up control 106 which is adjusted by the operator and moves during the honing operation until the predetermined condition, in this case, the fixed size of the surface being honed, is reached. A plate member 108 is movable with the control 106 against which it is biased by spring 110. An operating member 112 is pivotally mounted on a shaft 114 and has one arm 116 engaging the member 108 and another arm 118 operating a dial gauge 18. The latch member 54 is rotatable on the free end of a shaft portion 122 of a member 124 which is rotatable with shaft 114 and has a pin 126 engaging an edge 128 of member 112. As honing proceeds, the member 124 and shaft 122, together with latch member 54, move counter clockwise under the pressure of leaf springs 130, the portion 52, upon the final size being reached, moving past portion 50 to release latch member 44 and permit member 22 to rotate about its pivot 42 so that the pin 82 collapses the latch members 66, 68 to stop the honing operation by movement of arm 32 which is damped by a dash-pot means 136. A knob 140 can be adjusted to prevent latching of the members 66, 68 in their over-centre position.