Lumber, its manufacture and distribution . St a? ft ~3 c3 bC Oh! - T3 c c ?<*i—I 6 32 SAWMILL EQUIPMENT order to throw off the power and stop the chain in case a log is notthrown upon the deck before it reaches the end of the trough. Thepower driving the chain can be thrown on or off by means of a lever,at the head of the deck, which is under the control of the deck man. The dimensions of the trough conform to the size of the logs handled,the width of the base, inside measurement, often being from 12 to 15inches. The sides slope outward at an angle of from 45 to 60°. Astandard type of the l
Lumber, its manufacture and distribution . St a? ft ~3 c3 bC Oh! - T3 c c ?<*i—I 6 32 SAWMILL EQUIPMENT order to throw off the power and stop the chain in case a log is notthrown upon the deck before it reaches the end of the trough. Thepower driving the chain can be thrown on or off by means of a lever,at the head of the deck, which is under the control of the deck man. The dimensions of the trough conform to the size of the logs handled,the width of the base, inside measurement, often being from 12 to 15inches. The sides slope outward at an angle of from 45 to 60°. Astandard type of the log haul-up is shown in Fig. 14. The endless chain may be of the flat-link or the round-link type,the former being made from steel bars from \ to f inch in thickness,while the latter is made from 1- or If-inch steel, each link measuringover-all from 9 to 9j inches. The log dogs, attached to these chains,are of many types and sizes, two common forms being shown in Fig. Fig. 15.—Two Types of Jack Chains and Log Dogs used in elevating Logs fromWater Storage to the Sawing Floor of a Sawmill. Round-link Chain (upper)and Flat-link Chain (lower). They are designed so that they can be replaced readily in case theybecome broken or worn. The chains travel over an idler at the lowerend of the trough and sometimes over an idler, or knuckle, at thepoint where the chain leaves the trough and feeds on to the log jack. Log jacks are either single-geared or double-geared, and are arrangedeither for friction drive or for straight belt drive, with tightener pulleyfor throwing the power on or off. They require from 25 to 40 horse-power to drive them. A single-geared jack has a main gear wheelattached to a shaft, which also bears a sprocket for driving the endlesschain. The main gear wheel is driven by a pinion mounted on the sameshaft as the driven pulley, which is actuated by a friction or by a speed of the chain varies from 50 linear feet per minute when
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1922
