The Origin of Alligator Machines

7 comments written by Joshua Trentine

On October 15th at the Renaissance Exercise Conference one of our guests asked where the idea came from to make a variably timed cam work on the RenEx machine. Ken Hutchins went on to describe and draw the explanation. This is an entertaining and practical story that relates to new features of the RenEx gear. Once upon a time we thought this technology was best applied to single joint exercises, although today we are seeing that it is at least as important, if not more so, on our Compound Row, Pull Down and especially Trunk Extension. In a future post we will describe how this feature is being incorporated in a very important prototype that is being finalized in our shop at the time of this blog post.


Origin of “Alligator Machines” or “Alligator Crank”

Parallelogram forces
is a term I learned from my father. I originally heard my father refer to parallelogram forces in the context of capturing large live alligators.

Roy Harris is an old family friend, and his family members were patients of my father. Roy became a celebrity in 1958 when he fought Floyd Patterson at Wrigley Field for the World Heavyweight Boxing Championship. He appeared on the cover of the August issue of Sports Illustrated in 1958 as well as in an issue of Life pictured holding an Alligator by the tail. Since then Roy has been a real estate broker with my brother Kam and held the post in my home county as county clerk. He is an attorney and taught school before that.

My father had many hobbies, some as a naturalist. One included was his admiration for alligators. He learned of Roy’s shared interest, and that Roy had perfected several techniques to catch large alligators that inhabited the lakes in East Texas. One of these applied the use of parallelogram forces, a concept I understood without really appreciating the appropriateness of the term until I began to draw pictures on the dry-erase board in order to explain the cam timing mechanism in the Leg Curl machine for which this technology was first applied.

Ken Describes Parallelogram Forces at the RenEx Conference

Although Roy had never used nor heard the term, parallelogram forces, here is his technique: He and his assistants went to a lake and found the largest alligator possible. While in a flat bottom boat and while blinding the alligator with headlights they looped a rope around the alligator’s neck. Of course, the alligator immediately fled into the water, and Roy’s crew let it have as much rope as it needed. However, Roy’s crew hurried to the nearest tree to tie the rope.

It would have been convenient to tie the rope to a tree on land, but that was usually impossible. Even better would have been to get the rope to a winch truck located on the shore, but now we’re talking fantasyland. Usually, the best that could be realistically hoped for was a tree in the water.

Ken Describing the "Alligator Machines" at the RenEx Conference

Once tied, the capture team required at least 3 strong men. One man was stationed at the tree to cinch up the rope as the others provided slack in the rope. The other two were in the boat at a location where the rope was at a convenient height out of the water. One man in the boat rowed the boat in a direction perpendicular to the rope as the second man pushed the rope with his hands and then whistled to the man at the tree. At the signal, the rope was released by the boat crew and cinched by the tree man. Then the boat crew reversed their direction and pushed the rope perpendicularly again for another bite. This often went on all night and into the next day.

As long as the angle pushed into the rope was close to 90 degrees and the rope was relatively great in length, the boat crew possessed an awesome mechanical advantage over the alligator. As they pushed so far as the angle grew meaningfully smaller they lost advantage. It was at this point that they always signaled the tree man to take up more on the cinch.

Note that it did not matter, if clearance was available, which perpendicular direction the boat crew pushed against the rope. The geometry was the same in either direction, which if both possibilities are drawn, portrays a parallelogram in that plane. Also note that any plane would have sufficed. If the clearance was available, the same could have been accomplished by lifting the rope or pulling it downwards, which I am certain Roy did on occasion depending on the circumstances.

If you study the Renaissance Exercise Trunk Extension Machine, or any of the RenEx Alligator Machines, you can almost see Roy’s Crew and that large alligator. Imagine that the movement arm axle is the tree, the cam axle is the alligator and the plunger is Roy in that flat bottom boat. Hence the name, Alligator Machines.

Ken Hutchins

RenEx Equipment Trunk Extension Machine

Copyright of 2002 by Ken Hutchins

P.S. Please leave your comments below, we’d be happy to reply!

{ 7 comments… read them below or add one }

avatar Joshua Trentine November 1, 2011 at 3:23 pm

In the picture Ken is drawing (above) on the dry erase board you can see Roy’s row boat in the middle, the alligator at the bottom, and the tree at the top of the dry erase board.

In our trunk extension machine pictured above the alligator is at the top(the cam axle), the tree is at the bottom (the movement arm axle is the tree), and Roy is in his row boat (the plunger) in the middle.



avatar Russ Wakefield November 1, 2011 at 7:32 pm

I was the one that asked that question at the seminar. It was a pleasure because I don’t recall ever hearing it before. It explained alot.


avatar Joshua Trentine November 1, 2011 at 9:41 pm

Great question Russ


avatar Russ Wakefield November 1, 2011 at 7:37 pm

Also I purchased Ken’s new book I encourage anyone that hasn’t yet invested in it to do so. I forgot some fine points over the years and learned some new ones Renex Squeeze explained in detail ect… and many other tools for the progressive trainer.


avatar Joshua Trentine November 1, 2011 at 9:41 pm

A must have manual for anyone who does this


avatar Tiffanie November 4, 2011 at 8:19 pm

I’m very curious about the Alligator Crank. Clever name.
Also, I see that Russ mentioned Ken’s new book. How much are they and where could i obtain my own copy?


avatar Joshua Trentine November 7, 2011 at 10:33 pm

Thanks Tiffanie!

We will be making an anouncement very soon about the book.



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