Patent GB-797884-A (GB)
Title: Improvements in or relating to vertical boring mills
IPC: G05B19/06
Filed: 1954-10-15
Abstract: 797,884. Boring- and turning-mills. BULLARD CO. Oct. 15, 1954 [Oct. 15, 1953], No. 5211/57. Divided out of 797,883. Class 83 (3). [Also in Group XXXVII] A pendant-control for a vertical boring-mill comprises a housing, a rotatable shaft in the housing, switch-operating dogs fixed to and rotatable with the shaft, a number of switches within the housing and switch-supporting means movable from a position where the switches co-operate with the dogs to a position where they are unaffected by the dogs, the rotation of the shaft being prevented until the supporting means is moved to the latter position. The arrangement of the machine and its gear drive means are described in Specification 797,883. The pendant control P, Fig. 18, is suspended from the machine conveniently to the operator and may be automatically adjusted vertically by a switch 328. A switch 329 projecting from the lower end of the pendant starts and stops the work-table. The pendant is divided into five compartments; the lowermost contains a switch for turret indexing and the one above this has a controller for the speed of the workspindle. The remaining compartments 306, 307, 308, for controlling the feed and traverse speeds of the ram, turret and side-heads respectively, in all possible movements, are identical. The one, 307, for controlling the turret head will be described. Switch construction. The switch-gear in the compartment is shown diagrammatically in an elongated form in Fig. 17. Solenoids for controlling the sliding gears for the different feed speeds, as described in Specification 797,883, are operated by switches 347, 348, &c., and clutches for the various directions of movement of the turret head are controlled by switches 361-365. Two ball-ended hand levers 311, 312 for the feed and traverse respectively project from the compartment 307. Each lever may be moved to eight positions and the lever points to the direction in which the head will move. To obtain this control the inner end 357, Figs. 17 and 26, of a lever engages a vertical slot in a horizontal bar 358 and also an aperture in a vertically-slidable bar 363. Horizontal movement of the hand lever 311 moves the bar 358 which has rack teeth engaging a pinion 359, Fig. 17, which engages a vertical rack 360 to operate switch 361 or 362. Vertical movement of this hand-lever moves the rod 363 which closes either switch 364 or 365. Diagonal movement operates both the horizontal and vertical bars so that, e.g., if the lever is moved to the left and upwards, switches 362 and 365 would be closed. The lever 312 operates similarly for traverse motions. Speed changes for feed and traverse are controlled by a rotatable knob 314, Figs. 17 and 21, which is keyed to a spindle 341 carrying a switch-operating drum 333. Dogs 342 project from the latter in predetermined arrangements and the knob 314 is indexible to twenty positions through a " clicker " device 406, 407. This knob cannot be turned to change the speed until the switches 347, 348, &c. have been moved to a position unaffected by the dogs. The switches, e.g. 350, 346, Fig. 24, are carried above and below the drum 313 by pairs of levers 331, 332, rockable about pivots 401, 402, respectively. The end pair of levers have cranked-extensions with lugs 400, 399 which are engaged by the end of a T-shaped member 398 which slides transversely in a guide in the switch compartment. A cam 330 secured to the sleeve of a second knob 313, and capable of limited rotation through a quarter-turn, presses the member 398 against the levers 331, 332 to prevent their opening. In this position, a stop 405, Fig. 27, secured to the lever 331, engages the ratchetwheel 406 and prevents the knob 314 from being adjusted. When the cam 330 is turned to enable a spring 403, Fig. 24, to force the arms 331, 332 and the other switch-supporting arms connected to rods 401, 402 apart, the stop 405 is released and knob 314 may be turned to bring a new set of dogs 342, Fig. 21, into line with the switches for a new feed speed, shown in an aperture 315. The arms 331, 332 are then closed together by turning knob 313, and tappets 404, Fig. 24, bear against the dogs 342 to close the selected switches. The arms 331, 332 carrying switches controlled by levers 311, 312 when moved apart, push spring-pressed plungers 420, Fig. 26, into recesses such as 419<SP>1</SP> to prevent displacement of the hand-levers 311 &c., until the selected feed has been established by returning disc 313 to the position rendering the feed switches effective by their coaction with dogs 342 on cam 333.