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Our Class: GripHoist 101

The basic elements of a GripHoist setup are shown here: the GripHoist machine with crank handle attached, a suitable anchor for it which in this case is an old tree stump, and one or two GripHoist operators. Pete will crank and the cable to the left of the picture will slowly and forcefully be pulled through the machine by a cam. At the other end of the cable is the root ball which is being pulled out of the ground. When Pete gets tired, Dave will spell him at the crank. The anchor is a huge stump attached to the small tree, and it is wrapped by a sling which is attached to the GripHoist by a clevis.

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At the other end of the cable is the root ball being pulled out of the ground. This first picture shows the GripHoist anchored to a huge boulder and Bill is at the crank. It also shows how the chain loops once around the neck or crown of the root ball, and it cinches down on it when under tension. The second picture shows the case when one bush is used as an anchor while another bush is being pulled. Another example of a resourceful anchor and anchor sling is shown with a long straight pull to a root ball in the distance. Mike is managing the tail cable to keep it from forming a loop on the ground which could kink. But then, kazow!, a root breaks at the anchor root ball and it is now starting to lift out of the ground. But that's OK since this one also has to be pulled out. The last view is a review of everything in a straight-pull setup, with Pete at the crank, Dave reporting on progress, and Mike is back there managing the tail cable.

Two Root-Pulling Configurations

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We show here another basic straight-pull setup. When the GripHoist crank is moved through its full arc the cable is pulled less than an inch. Both cranking directions are effective in moving cable, so a front-back-front crank cycle moves the cable only between one and two inches. Note that the midpoint of the cable is being protected from rock abrasion by the handle of a tool. The maximum tension which the model TU32 GripHoist is rated at is 4 tons, 8,000 pounds. In the following views, we show a snatch-block setup which can increase this maximum force.

Snatch-Block for the Big Pulls

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Here is the snatch-block setup. A single-sheave pulley is attached to the root ball while the end of the cable is attached at the same big tree stump which is used for anchoring the GripHoist. The maximum pull obtained thus is theoretically twice that of the straight-pull, and the cable now moves at only half the former speed. Up the trail, as we began encountering larger root balls which were in tighter, more compact earth, the snatch-block came into standard use. You can see this situation in the second picture. Picture 3 is a close-together anchor and root ball setup which used a snatch-block and the end of the cable is now anchored to a different tree than the GripHoist. It's a little hard to see, but the pulley is just behind the root ball and its cable runs to the left to a sling. Since there is an angle between the cable going to and from the pulley, the maximum available tension is reduced. But it is still stronger than a straight pull without the snatch block. Mike is using a Pulaski to cut at roots coming up with the root ball to ease the work of the GripHoist operators and the tension on the snatch-block. The last photo was taken in order to show a root ball which has been dug to its crown and is ready for the chain or cinch-cable to be attached.

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