GB1184551A - Improvements relating to Buffer Arrangements for Arresting Rotational Motion. - Google Patents

Abstract

1,184,551. Mechanical buffers. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. 14 March, 1967 [18 March, 1966], No. 11995/66. Heading F2S. A buffer, for arresting the motion of heavy moving objects, e.g. radar tracking equipment, and which considerably limits recoil, comprises a stationary arcuate housing H, which is adapted to encircle the shaft, not shown, e.g. of a radar head and which has an inwardly facing annular groove with a pair of confronting surfaces between which is located a ring of blocks X each of which is separated from the next by a compression spring, e.g. a stack of Belleville washers S, and has its outer curved surface fitted with a friction pad P which engages arcuate surface of the base of the groove G, the housing H being provided with an end stop Z 1 at least at one end of the confronting surfaces and a movable end block Y 1 which is engageable by the moving object to be arrested the arrangement being such that the movement of the end block in arresting the said rotational motion of the object is resisted by the springs the resulting deflection of which causes an increase in frictional engagement between the buffer blocks and said arcuate surface and a corresponding increase in the resistance to motion of said object. End blocks Y 1 , Y 2 , at the ends of the ring of blocks X, abut respectively fixed stop blocks Z 1 , Z 2 and each carries a pivoted arm D which is maintained in a normal retracted position by a leaf spring R but which is pivotable radially inwardly by a lever L pivoted to the corresponding stop block Z. An operating mechanism O is mounted at the datum point of the housing and comprises a Geneva wheel W, a centre coupling C, and a peg drive coupling PC which is adapted to engage and pivot one or other of the levers L. In operation as a column CO, Fig. 3, of the radar head rotates in an anticlockwise direction from the datum position a spindle SP on a plate PL mounted on the column CO rotates the wheel W through 180 degrees but, due to the lost motion between the co-operating drive surfaces of the operating mechanism, this movement has no effect upon the buffer. As the column rotates through a further revolution the wheel (W) is first moved through 60 degrees so that the coupling drive surfaces contact one another, and then through a further 60 degrees during which the peg drive PC contacts the corresponding lever L. Under normal circumstances the radar head would stop at this point and reverse direction so that the column would be rotated through four revolutions in a clockwise direction and so on. Should, however the stopping and reversing mechanism fail continued anticlockwise rotation of the column CO with a further 60 degrees rotation of the peg drive PC, pivots the lever L of blocks Z 2 to cause the buffer arm D to pivot radially inwardly into the path of a buffer plate B on the column (CO) so that the buffer is brought into action. Should the radar head overshoot in the opposite direction then the other buffer plate (A), Fig. 4, not shown, would co-operate with arm (D) of block (Y 1 ).