|Wind Systems for Pumping Water: A Training Manual (Peace Corps, 1984, 93 p.)|
TOTAL TIME: 2 Hours
OBJECTIVES: To investigate some of the methods used to join materials.
To join different materials in 8 variety of ways and test the joints.
To learn about triangulation as a simple method of improving support structures.
MATERIALS: Small poles or lumber, pipes, fastening materials (rope, nails, wire, screws, bolts, rawhide, etc., as available)
Tools for the above as necessary from the shop.
Step 1: 30 minutes
Discuss the different types of fastening techniques available.
In a discussion, solicit local knowledge about local methods and materials for fastening and joining materials. Show samples and do demonstrations whenever possible using local participants.
Step 2: 30 minutes
Attach some poles or pipes using the various methods. Giving projects to groups of 2 or 3.
Poles can be fastened with metal pins made from concrete reinforcing rod or other similar metal. Drill the holes, insert the pin, put washers on the ends, bend the ends of the pin over to form a tight connection.
Step 3: 30 minutes
Test some of the materials and attachment methods.
Employ destructive testing and show how it can be done without instruments by estimating the forces involved.
Step 4: 15 minutes
Make squares and triangles using lashings. Build a hoisting tripod.
Step 5: 15 Minutes
Test them and discuss triangulation for bracing.
RESOURCES: Copies of Attachments 8-A, 8-B, and 8-C.
Figure 1: Various Types of Pole Lashings
Figure 2: Tripod, Shear Leg, and Other Pole Lashings
Fig. 165: Poles Lashed and Wedged in the manner shown in this illustration are held securely, with but little liability of their slipping or working loose. After the lashings have been applied, small wooden wedges are driven between them and the poles as shown. This tends to take up any slack in the lashings.
Fig. 166: The Telegraph Hitch is used on long poles and piles when it is required to hoist them vertically. To make the hitch take a piece of line of sufficient length, middle it and make cross turns around the pole as shown. A short bar is then placed under the final cross turn and a turn is taken about it, after which the ends of the rope are secured with a Reef Knot forming a bight for the hoisting hook.
Fig. 167: The Putlog Lashing is employed when it is required to lash two square timbers together. The manner in which it is formed is clearly shown in the illustration.
Fig. 168: The Packing Knot is frequently used to hold large pieces of timber together. It is also used in stone quarries to secure large blocks of stone on the cars which haul them. The small block of wood used in the illustration is intended to represent a slab of stone. Two or three turns with a heavy line are taken around both the slab of stone and the dolly or car upon which the stone rests. A piece of timber or a metal bar is then inserted under the lashing rope and it is twisted until all of the slack is taken out of the lashing. The piece of timber used as a lever is then in turn lashed to the body of the dolly as illustrated.
Fig. 169: The Double Chain Lashing shows the manner of making a line fast to a pair of crossed shears. The end is seized to the standing part of the rope after a sufficient number of turns have been taken about the shears.
Fig. 170: A Loop Lashing such as that shown serves to illustrate the manner in which the bight of a hawser is made fast to a pair of crossed shears. The bight of the hawser is passed over, under, and around the legs of the shears in the manner shown, after which the loop of the bight is placed over the top of one of the legs, leaving the standing part of the hawser as shown.
Fig. 171: The Crossed Lashing is another method used to make a line fast on the head of a pair of crossed shears. Any number of turns may be taken as shown, being crossed in back, after which the end of the lashing is made fast to its standing part with a seizing.
Fig. 172: The Square Lashing shown in this illustration is used for much the same purpose as that shown above. It is made in the same manner except that the turns are parallel and not crossed.
Fig. 173: The Shear Head Lashing is used to lash the heads of a pair of shears together. The shears are laid parallel to each other on the ground; a number of turns are taken around them, after which several cross turns are taken. The ends are then finished off with a Reef Knot.
Fig. 174: The Shear Leg Lashing is employed to attach a cross member to the lower ends of the legs of a pair of crossed shears. The methods employed are clearly evident in the illustration.
Fig. 175: The Tripod Lashing is an interesting method frequently employed for holding the three legs of a tripod together. The three members are first placed in the position shown and a strong lashing is passed around all of them. Cross turns are then made between the shear heads, and the ends of this line are secured with Clove Hitches as shown.
Fig. 176: The Square Cross Shear Lashing is a very simple but secure method of passing a lashing which is commonly used.
Fig. 177: The Herringbone Cross Shear Lashing is made by taking a number of Figure-of-Eight Turns about the two members after which cross turns are added above and below the cross shear. These tend to make the lashing more secure.
Reference - Encyclopedia of Knots and Fancy Rope Work