Elevating Machinery For Service or Repair Work -
By Rory S. McLaren - Director
|We are concerned that people who work on elevated machinery are at risk of a debilitating injury or death if they get caught between the machine's tire and the ground.
When is this type of accident most likely to occur? -
When a machine is jacked up, or lifted off the ground for service or repair work and the wheels are rotating, or tracks are in motion, while the work is being done.
It is oftentimes necessary to lift a machine off the ground to set, for example, the neutral position for a closed-loop (hydrostatic) transmission.
The wheels or tracks could also begin to rotate unexpectedly if the machine's engine is running, and vibration causes the forward/reverse control lever to move.
What types of machinery are most susceptible to this problem? -
Small skid-steer loaders, tractors, and rubber-tired or track vehicles are examples of machines that are most likely to be elevated for service or repair work.
|What could happen? -
If the distance from the machine's tire or track to the ground is less than the height of a persons body when lying down (add the height of a creeper if necessary) he/she could unexpectedly get caught between the machine's tire or track and the ground.
The ribbed track or ribs on a tire could snag a person's body, and drag it through between the moving member and the ground.
The dynamics are very similar to the operation of a softball or baseball pitching machine.
What kind of injuries could a person sustain? -
Injuries could range from severe limb injury, to severe bodily injury. Needless to say, under certain conditions, a person could easily suffer fatal injuries.
Who is most likely to be exposed to this type of accident? -
Mechanics, in the course of their work, are the primary candidates for this type of accident. However, machine lubricators and oilers could also be candidates. Engineers also might be subjected to this situation if they are under a machine in the course of conducting design work.
What must be done to prevent this type of accident? -
First, of all, be aware that it can happen at any time. More importantly it can happen to you!
Here are a few suggestions that will help to avoid this type of accident:
|Safety planning begins by placing the machine on a flat, stable surface - preferably concrete.
|If the machine is disabled, and it is parked on an insecure or unstable surface, suitable plates must be placed under the machine. Jack stands can sink into the ground due to the machine's weight. If the machine can be towed, or transported, move it to a secure, stable work area.
|If it is necessary to elevate a machine to perform service or repair work, or to make adjustments - while the engine or electric motor is running - lift the machine high enough off the ground to prevent yourself or others from getting crushed between the tire or track and the ground. If a creeper is going to be used, add its height to the estimated safe working elevation.
|Place adequate and substantial supports under the machine. NEVER enter the underside of any machine that is supported only by a hydraulic jack(s). ALWAYS use proper and adequate jack stands. Too many supports is better than not enough!
|Place supports under four corners of the machine. This will prevent it from unexpectedly tilting or moving.
|Make sure that the area is well vented to avoid being overcome by hazardous exhaust fumes.
|If it is necessary to reach up above a rotating driveline, remove loose clothing. NEVER underestimate the severity of injuries that are caused by people's clothes getting caught in rotating drivelines. Coveralls are made from very strong and durable materials. It is highly unlikely that a person will pull free once clothing is snagged in a rotating shaft.
|If it is necessary to use a "come-along" to drop, for example, a heavy belly pan to the ground, REMOVE THE CABLES BEFORE STARTING THE MACHINE. DO NOT LET CABLES OR CHAINS DANGLE FROM THE TOP OF THE MACHINE AND LAY ON THE GROUND WHERE A PERSON IS WORKING.
IF A CABLE OR CHAIN GETS ENTANGLED IN A ROTATING DRIVELINE WHILE A PERSON IS LAYING ON TOP OF IT, IT WILL SNARE THE PERSON AND DRAG HIM/HER UP INTO THE ROTATING MEMBER. THE SEVERITY OF THE OUTCOME IS PREDICTABLE - THE PERSON WILL PROBABLY GET MUTILATED!
|Run the machine only long enough to perform the work.
|Once the work is complete, return the machine safely to the ground.
|Whenever starting a machine after performing work on the neutral control mechanism - this applies especially to closed-loop (hydrostatic) drives, ALWAYS clear the area around the machine and give colleagues a "heads-up" before starting. Also, have a person at the machine's "kill-switch" (if it is safe, e.g., do not stand between wheels to gain access to a kill switch), in the event that the machine unexpectedly moves.
|Do not let complacency be the reason why you don't have dinner with your family tonight!
Always follow the machine manufacturer's safety recommendations. Due to the wide variety of machine designs, there may be additional important safety guidelines.
If you are at all uncertain, ASK!
DO NOT design and build your own machine supports. Machine stability and weight are critical factors and can easily be understimated. Ask your company's engineer(s), or the machine manufacturer for help.
Fluid power safety doesnt just happen, it has to be pursued."
The Fluid Power Training Institute presents the only "safety-based" hydraulic training workshops in the world. We invite you to visit the website and sign up so you can begin to work safely with hydraulics.
Rory S. McLaren
Fluid Power Safety Institute
The Fluid Power Safety Institute welcomes constructive dialogue regarding our safety bulletins. Your comments are welcome.