Mounting the Chain

After modification, it becomes quite simple to mount or remove chain from the saw. 

To mount the chain (1). retract the bar by slacking off about a half turn on the bar nuts, just enough to enable you to loosen the chain-tension screw. (Count the number of turns it takes to loosen the chain-tension screw and you ll find it easier to tension the chain later.) Hold the chain in the proper direction of travel and insert it behind the clutch and onto the chain sprocket. The chain should be going away from the saw engine at the top of the bar and toward the engine at the bottom. 

Thread the chain through the space between the thrust skid and the bar (2). Place the chain between the chain-guide plates and feed it through the thrust-skid space (3). 

holding the chain at the center of the bar top and bottom, move it a few revolutions around the bar to remove kinks. Then hold the chain at the center of the top of the bar and lift it up out of the groove. If the drive links just clear the top of the groove under normal finger pressure, and you can easily rotate the chain by hand, the chain is properly tensioned (5). 

With the tension set correctly, tighten the bar nuts (6). Rotate the chain around the bar, lubricating it with the manual oiler as you go. Start the engine and run the chain a bit, then slop it and check the tension, adjusting if necessary. New chain tends to stretch on break-in, so check the tension again soon after you start milling. 

---

If pressing equipment with appropriate tooling is available, mount the chain in a chain vise (Figure 14-4). Then press the pins out of one pin link plate (Figure 14-5). If pressing equipment is not available, the pins may be pressed out of the pin link plate with a pin extractor (Figure 14-6). The pin links removed from the chain normally are not reusable. 

Mount the chain in the grinder, then adjust the pawl so the stone can pass into the cutter gullet with zero clearance between the stone and the top edge of the cutter (I). The chain should be positioned so that the stone Just brushes past the edge of the cutter. Gently lower the stone into the gullet and adjust its depth stop. 

Now for the chain. Chain often gets tangled into what seems like a hopeless mess when it is moved around. To roll the kinks out, hold the chain in both hands. Starting with the most serious kink (4), roll the chain as shown (5). Pull the two loops into the final loop, and you re ready to mount the chain on the bar (6). 

Super-capacity elevators are continuous type elevators in which the buckets are mounted between two strands of chains. This arrangement makes it possible to handle a larger volume because the bucket can be extended in back of the chain. Elevators of this type are capable of handling up to 375 m /h. 

Chain Tension. All chain drives should have some means of controlling the chain sag caused by normal joint wear. This is of utmost importance when the drive is subject to shock or pulsating loads or to reversals in direction of rotation. The most common methods taking up chain slack are (1) drive units mounted on adjustable base plat, slide rails, or similar units these are used extensively in motor-driven applications and (2) the use of adjustable idlers (Figure 3-40) and chain tensioners. 

Adjustable-idler sprocket wheels must be securely mounted and should engage the slack or nonload carrying side of the chain. At least three teeth of the idler must be in full engagement with the chain. To take up the slack of accumulative wear of the chain, an idler needs only to be adjustable for slightly more than two chain pitches. Finally, idler sprocket wheels should have at least 17 teeth. 

Oii-Disk Lubrication. This method is frequently used when a drive is not suitable for splash lubrication. It is highly satisfactory for moderate and semihigh-speed drives. The chain is kept above the oil level, and a circular disk, mounted to the lower wheel or shaft, dips into the oil about in. Figure 3-42 shows relative shaft positions best suited for oil-disk lubrication. 

The mounting evidence in the case of the curdlan triple helix (13)is that the chains can untwist slightly (or twist tighter) under different conditions giving rise to quite different x-ray diffraction patterns as the symmetry is destroyed. These changes should not be confused with complete untwining of the chains. 

Although the level of DDD used was low, it accumulated in organisms, each animal in the food chain gaining higher levels, until the animal at the top of the chain, the final predator, acquired levels that were lethal. This worried scientists when it was discovered. The same phenomenon applies to DDT. These examples illustrate what happens when excessive or even just larger than necessary amounts are used. There was already mounting public concern when, in 1963, Rachel Carson s book Silent Spring was published, which documented these occurrences and laid the blame on DDT. It had an enormous impact and the eventual result was that DDT was banned in many countries. 

Indexing machines are characterized by a rigid chain of stations. The construction design depends mostly on the complexity of the product to be mounted. The main movements (drives for transfer systems) can be effected from an electrical motor via an adapted ratchet mechanism or cam and lever gears or can be implemented pneumatically and/or hydraulically. Secondary movements (clamping... 

The deflection measurements are carried out by three geophones mounted on a 15 m chain 5 m apart. The chain is positioned on the ground and passes between the dual wheels. As the truck moves forward, it constantly places the chain down in front of the rear wheels. The chain remains at a fixed location on the pavement as the truck wheels roll over it. 

From the expression of the energy variation, two ways of grouping variables can be chosen, corresponding in fact to the chain mounting or to the ladder mounting. 

As mentioned in Section 8.1, there are basically two ways of assembling two dipoles in order to allow sharing of efforts or flows. The chain structure or serial mounting corresponds to a common flow whereas the ladder structure or parallel mounting corresponds to a common effort, as shown in Figure 8.12. 

---