04-03-1999, 12:01 PM #1rmooreFirehouse.com Guest
Inverted Step Chock Stabilization
A Thread from Ron Moore
The Inverted Step Chock
I am concerned about the difference in height between each level of a step chock. I feel that smaller differences in height allow for more accurate use of the chock.
The original concept of step chocks, introduced by a Florida extrication crew back in 1984, were constructed of dimensional 2x4 pine, making a step height of 1 & 3/4 inches.
Now, the latest version of the recycled rubber super step chocks have what I consider a huge step height between each level. Some even angle the step higher at the front edge, lower at the back.
I'm not sold on manufacturers ( Turtle, are you listening!) designing this big difference in step height. Wedging under the chock is normally done when the vehicle is too high for one layer of the step and too low for the next. Lifting the vehicle is also done under this same situation. These may really not be the best solutions.
On many occasions my solution has been to use a step chock upside down like a large wedge. For me, this allows a smooth surface for stabilizing the vehicle and seems to promote a more efficient, shorter chocking time. Now when I do this with a plastic step chock, the flat bottom surface is slippery and worn smooth. Unless I deflate the tires, the chock will probably work its' way loose.
Any suggestions on dealing with the huge step height designed into the newest generation of plastic step chocks?
04-04-1999, 02:39 PM #2ElmerAFirehouse.com Guest
We come from a poor rescue squad, so many of the things we have for stabailizing are those we have built ourselves. We took treated 2x6's and built step blocks. Ours are thirty inches in length with doubleed steps every 6" for a total height capaicity of 15" with each step being 3". We did this because of the amount of different vehicles we see. We drilled in and attached nylon rope handles for easy handling, but to make up the diffence of the 3" step height, each step block gets a 30" wedge. We used cut down 4x4 treated, going corner to corner. There is not any height from 0 to 18" that we cannot handle. We tie together 2 blocks and 2 wedges with rubber bands cut from inner tubes. Two rescuers can stabalize a side of a vehicle in a very short time.
There have been times when we have flipped the blocks over and used them aka "as wedges", but we have found that the angles produced will allow the vehicle to slide. In the times that the veicle has been close to the ground, we have layed the step blocks on their sided and used the wedges to make of the difference. We can get a 0 to 9" height adjustment.
All else, we can go back to the 4x4 cribbing blocks, just takes a little more time, but it is better to do it safe than to get one our own hurt
04-05-1999, 05:17 PM #3Marv WaltonFirehouse.com Guest
My suggestion is not to use them, if they don't suit your needs. Our Dept. has been making our own step chocks for years. Why spend $ when you don't have to. I too have a concern with the vehicle slipping on the slope of the inverted chock, even wooden ones. Also, there is less area making contact with the ground, making, in my opinion, a less stable vehicle. Let's just say I have never been a big fan of using step chocks in an inverted position.
04-06-1999, 09:49 AM #4K RomerFirehouse.com Guest
Most of commnets on "inverting stepchocks" have been posted, but I will put them in my own words.
We too use "homemade" wooden stepchocks, 30" long w/ 6" steps. For most vehicles they work well. The big vehicles (SUV, Suburbans, Vans etc. they dont work at all without supplemental cribbing to bring the chock to the vehicle.
In other forums relating to vehicle rescue, there is discussion on "keep inflated vs. deflate" the tires. I personnally am the deflate the tire in a controlled method fan. This of course after stabilizing the vehicle. Why do I go into this so far? I believe that if a vehicle is placed on an inverted stepchock on 3 or 4 points, the potential for the vehicle to slide down either side is increased.
The larger contact surface is the flat side, not the 6 tips of the chock. We in fact were "gigged" in a competition for putting wedges under the chock due to the reduced contact area. We still use the wedge method in real life, although a little difficult when we get of the asphalt.
As far as the slopes go on the mfg'd plastic cribbing, I dont have a problem with that, IF the chock is placed properly.
I do find the 3 point method interesting, and will try it as soon as I can get to the junkyard.
#1 - chock 4 pts, thinking about placement in conjunction with the tasks 20 min from now.
#2 - wedge under chock
#3 - deflate tires (controlled)
#4 - continueallay monitor status of cribbing
Wont work all the time, but in vast majority of the incidents we do, it does.
Thanks Ron.....good topic
Kevin Romer (firstname.lastname@example.org)
04-06-1999, 11:58 AM #5PTFD21Firehouse.com Guest
I agree with Mr. Walton DON'T use them. Our dept has used 2"x4" on a 2"x6" base for many years with success. We commonly use them in the inverted position without any trouble. We also deflated the tires whenever the step chocks are used.
<a href="http://members.aol.com/PT10FD/info.htm">Pittsfield Twp. F.D. </a>
04-20-1999, 12:39 AM #6FireDanFirehouse.com Guest
We utilize inverted step chocks on a daily basis, with no problems. I have found that 24" units made of 2x6 with a double layer base and 4" steps seems to be the most versatile for our applications. We also angle the front blocks 45 degrees to the rear and the rear blocks 45 degrees to the front to give improved swing for doors. Have yet to encounter a problem with this technique. I do agree with the other posts though, in that it is imperitive to maintain a watchful eye on any blocking or shoring. We also do NOT deflate tires.
04-20-1999, 04:46 PM #7SBrooksFirehouse.com Guest
Placing a small (6-10") wedge on the step seems to help. Never had a problem with the car slipping off of it (it is hardwood)
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