Fig. 1557.
The iron planing machine, or iron planer as it is termed in the United States, is employed to plane such surfaces as may be operated upon by traversing a work table back and forth in a straight line beneath the cutting tool. It consists essentially of a frame or bed a, [Fig. 1557], provided on its upper surface with guideways, on which a work carrying table t may be moved by suitable mechanism back and forth in a straight line.
This frame or bed carries two upright frames or stanchions b, which support a cross-bar or slide c, to which is fitted a head which carries the cutting tool.
To enable the setting of the tool at such a height from the table as the height of the work may require, the cross slide c may be raised higher upon the uprights b by means of the bevel gears f, g, h, and t, the latter being on a shaft at the top of the machine, and operating the former, which are on vertical screws n, which pass down through nuts that are fast upon the cross slide c.
To secure c at its adjusted height, the uprights are provided with T-shaped slots h h, and bolts pass through c, their heads being in the T-grooves, and their nuts exposed so that a wrench may be applied to them.
The faces of the cross slide c are parallel one to the other, and stand at a right angle to the V-guideways on which the work table (or platen as it is sometimes termed) slides; hence the cross slide will, if the table is planed true or parallel with this cross slide, be parallel with the table at whatever height above the table it is set, providing that the elevating screws, when operated, lift each end of c equally.
The construction of the head d corresponds to that of the head shown in [Figs. 1497] and [1498] for a shaper, except that in this case the swivel head is secured to a saddle that slides along c, being provided with a nut operated by a feed screw j, which moves d along c.
The mechanism for operating the work table or platen t is as follows:—p p′ are two loose pulleys and p′′ is a driving pulley fast on the same shaft. This shaft drives, within the casing at q, a worm operating a worm-wheel, which actuates inside the frame a and beneath the work table a train of gears, the last of which gears with a rack, provided on the underneath side of the table.
The revolutions of this last wheel obviously cause the work table to slide back and forth while resting on the V-guideways provided on top of the frame a, the direction of table motion being governed by the direction in which the wheel revolves.