This machine is driven by a belt connecting pulley G with an overhead shaft. When the machine is in operation, this pulley is engaged with the main driving shaft by a friction clutch F controlled by lever L. This main shaft drives through gearing a vertical shaft I, which by means of other gears in the spindle-head imparts a rotary movement to the spindle. As a machine of this type is used for boring holes of various diameters and for a variety of other work, it is necessary to have a number of speed changes for the spindle. Nine speeds are obtained by changing the position of the sliding gears controlled by levers R and this number is doubled by back-gears in the spindle-head and controlled by lever J.
The amount of feed for the spindle, spindle-head, platen or saddle is varied by two levers K and K1 which control the position of sliding gears through which the feeding movements are transmitted. The direction of the feed can be reversed by shifting lever O. With this particular machine, nine feed changes are available for each position of the spindle back-gears, making a total of eighteen changes. The feeding movement is transmitted to the spindle-head, spindle, platen or saddle, as required, by the three distributing levers T, U and V, which control clutches connecting with the transmission shafts or feed screws. When lever T is turned to the left, the longitudinal power feed for the spindle is engaged, whereas turning it to the right throws in the vertical feed for the spindle-head. Lever U engages the cross-feed for platen P and lever V, the longitudinal feed for saddle E. These levers have a simple but ingenious interlocking device which makes it impossible to engage more than one feed at a time. For example, if lever T is set for feeding the spindle, levers U and V are locked against movement.
The feeds are started and stopped by lever M which also engages the rapid power traverse when thrown in the opposite direction. This rapid traverse operates for whatever feed is engaged by the distributing levers and, as before stated, in a reverse direction. For example, if the reverse lever O is set for feeding the spindle to the right, the rapid traverse would be to the left, and vice versa. The cross-feed for the platen can be automatically tripped at any point by setting an adjustable stop in the proper position and the feed can also be tripped by a hand lever at the side of the platen.
All the different feeding movements can be effected by hand as well as by power. By means of handwheel N, the spindle can be moved in or out slowly, for feeding a cutter by hand. When the friction clamp Q is loosened, the turnstile W can be used for traversing the spindle, in case a hand adjustment is desirable. The spindle-head can be adjusted vertically by turning squared shaft X with a crank, and the saddle can be shifted along the bed by turning shaft Y. The hand adjustment of the platen is effected by shaft Z. The spindle-head, platen and saddle can also be adjusted from the end of the machine, when this is more convenient. Shafts X, Y and Z are equipped with micrometer dials which are graduated to show movements of one-thousandth inch. These dials are used for accurately adjusting the spindle or work and for boring holes or milling surfaces that must be an exact distance apart.
Fig. 2. Horizontal Boring and Drilling Machine with Vertical Table Adjustment
Horizontal Boring Machine with Vertical Table Adjustment.—Another horizontal boring machine is partly shown in [Fig. 2]. This machine is of the same type as that illustrated in Fig. 1, but its construction is quite different, as will be seen. The spindle cannot be adjusted vertically as with the first design described, but it is mounted and driven very much like the spindle of a lathe, and adjustment for height is obtained by raising or lowering the work table. The design is just the reverse, in this respect, of the machine shown in [Fig. 1], which has a vertical adjustment for the spindle, and a work table that remains in the same horizontal plane. The raising or lowering of the table is effected by shaft E, which rotates large nuts engaging the screws S. Shaft E is turned either by hand or power.
The main spindle is driven by a cone pulley P, either directly, or indirectly through the back-gears shown. This arrangement gives six spindle speeds, and double this number is obtained by using a two-speed countershaft overhead. The motion for feeding the spindle longitudinally is transmitted through a cone of gears, which gives the required changes, to a pinion meshing with a rack which traverses the spindle. The large handwheel H and a corresponding wheel on the opposite side are used for adjusting the spindle rapidly by hand. The yoke or outboard bearing B for the boring-bars can be clamped in any position along the bed for supporting the bar as close to the work as possible.