Referring now to the plan [Fig. 3140], and the side elevation, [Fig. 3142], the feed roll f is carried in a frame g, which is fitted on the slideway d, d, and receives a screw i, upon which is a hand wheel h; at the back of this wheel is the lever j, which is weighted as shown, so that the force with which feed roll f grips the work is determined by the weighted lever j, and may be varied to suit the nature of the work by moving the weight along j.
The construction of the gear for feed roll f′ is similar, as may be seen in the plan [Fig. 3140], f′ being in a slide g′, which has a screw i′, and hand wheel h′, a weighted lever corresponding to j acting against wheel h′. In proportion as f and f′ are opened out to admit thick stuff or work, the hand wheels h and h′, respectively are used to screw the screws i and i′ into their respective slides g and g′, and thus maintain the weighted levers in their requisite horizontal positions. The feed rolls e and e′ are carried in slides c and c′, and are adjusted to suit the thickness of the stuff or work by a hand gearing, which consists of the hand wheel a, seen in the plan and in the front elevation, [Fig. 3141], which drives the pinions b and b′, which operate screws for the slides c and c′, the latter being a left hand screw. The front rolls e and e′ are therefore held in a fixed position, whereas the back ones f and f′ may open out under the pressure of the weighted levers j, and thus accommodate any variation in the thickness of the work.
The rate of feed is varied to suit the nature of the work by the following construction: The friction wheel o and the hand wheel r are connected by a yoke q, [Fig. 3142], at the ends of which are the joints p, q, seen in the plan, [Fig. 3140]. Hand wheel r is threaded to receive the screw s, and it follows that by revolving r, the friction wheel o may be moved towards the centre of the friction disc n, which would reduce the velocity with which n would drive o, and therefore reduce the rate of feed. If the friction wheel o be moved from the position it occupies in the plan [Fig. 3140], to any point on the other side of the centre of the friction disc n, the direction of feed motion would be reversed.
Fig. 3143.
A band saw machine for the conversion of logs into timber, and constructed by Messrs. London, Berry & Orton, is shown in [Fig. 3143]. The logs are fixed to the carriage by dogs and the carriage traverses the log to the feed.
Reciprocating Cross Cutting Saw For Logs.—The machine shown in [Figs. 3144] and [3145] is designed for the purpose of cutting heavy and long logs into convenient lengths preparatory to cutting the logs up in other machines, and it is usually therefore placed at the entrance to the mill, where it is of immediate service as the lumber comes into the building.
The machine here shown is intended for logs up to 36 inches in diameter, is simple in construction, requires very little foundation, is easy to handle, and occupies but very little room.