Parts of Planer

Parts of Planer

Parts of Planer - A standard double housing planer has the following main parts.

(i) Bed
(ii) Work table
(iii) Column or housing
(iv) Cross rail
(v) Saddle
(vi) Tool head
(vii) Driving and feed mechanism.

A Double Housing Planer

(i) Bed The bed of a planer must be a weldment or casting twice as long as the table. The bed acts as the foundation of the machine. The other parts are attached to, or supported by the bed. The bed has accurately finished ways on which the worktable slides. The gearing or hydraulic cylinder for driving the table is housed under the bed.

(ii) Worktable The table is a heavy rectangular casting, which carries the work past the cutting heads. It travels on vee or flat ways of the bed. The table is driven either by a very long hydraulic cylinder or by a pinion gear driving a rack which is fastened under the center of the table.

The motor driving the pinion gear is of reversible type with variable speed.The upper surface of the table has T slots in it to facilitate the clamping of the work or vises and special fixtures with Tbolts. The top surface of the table also has accurate holes for supporting the stop pins etc.

The side of the table has a groove for clamping planer reversing dogs at different positions. In some planers, hydraulic bumpers are fitted at the end of the bed to avoid the table from overrunning.

(iii) Column or housing The frame of the planer is the same hollowbox type used on large milling machines. The frame is basically two heavy columns fastened together at the top with a large bracing section and fastened at the bottom to the machine bed.

This creates a very strong, rigid structure which will handle heavy loads without deflection.On a double housing planer, two housings or columns rise vertically at the sides of the machine. They support the crossrail and house the elevating screws and controls for the machine.

(iv) Crossrail The crossrail is a heavy box or similar construction. It is mounted in a horizontal position on the vertical ways of the housing. It slides up and down on vee or flat ways, controlled by hand or by poweroperated screws. These cross rails are so heavy that they are counterweighted, with either castiron weights or hydraulic cylinders, in order that they may be movedeasily and positioned accurately.

After being positioned, they are clamped in place. The purpose of the crossrail is to carry the vertical tool heads which by means of feed screws may be moved from left to right. It is very essential that the crossrail, when clamped, be parallel to the table for obtaining accurate machined surfaces.

(v) Saddle The saddle is fitted to the ways of the crossrail. On its front surface are ways to which the toolhead is fitted, together with a vertical feed screw that provides for a vertical movement of the toolhead. There are two saddles one for the left toolhead, the other for the right toolhead. Each one may be operated independently of the other.

(vi) Tool head The toolhead of a planer is similar to that of a shaper both in construction and in operation. The tool head is attached to the saddle which contains the tool post which. in turn, holds the cutting tool. The tool post is hinged to the head so that on the return movement of the table the cutting tool will be raised and ride on the top of the work.

This saves the cutting edge of the tool from being damaged and permits the automatic traverse feed to operate without interference. A feed screw is provided to move the toolhead with respect to work. The toolhead can be swiveled for taking angular cuts. There are four toolheads, two in vertical position on the crossrail, and the other two known as side tool heads mounted one each on the two columns below the crossrail.