Brake Press Guards

[fouratjohnjajou]

I was wondering if anyone has thought of a clever guarding technique for this piece of equipment. Having light curtains installed is simply not an option for our company seeing the costs involved. The guard should allow operator freedom, while keeping limbs and digits inaccessible from the machine, or tripping the circuitry some how to raise the break. I was wondering if anyone could help. Thanks.

 

[eromlignod]

They make hand pull-back strap devices for press brakes. I've seen them for years. Take a look here:

http://www.positivesafetymfg.com/Products.htm

Don
Kansas City

 

[fouratjohnjajou]

Thanks. I believe the province of Ontario (where I am) has banned those a while ago. I know they were common with the high tonnage punch presses. We do require the operator to hold the parts at times, the nature of the bends causes the part to have some movement, and special fixtures would be needed to dynamically compensate for the motion.

 

[BrianPetersen]

fouratjohnajou, I'm rather familiar with CSA Z142-02, which is the standard that the Ministry of Labour will require you to conform to. That standard does not adequately address operational needs of press brakes, and I've found it to be almost impossible to deal with press brakes if the workpiece has to be held. Pull-back straps are not banned (but their use is strongly discouraged) and if your operator needs to hold the workpiece close to the point of operation, they will not work anyway.

I have seen a single-beam optical device which shines along the length of the tooling that is specifically designed for press brakes. I don't recall who manufactures it. As I understand it, this device is approved in Europe, but I don't grasp how it can comply with the safety distance requirements here.

Small workpieces - best thing I know of is to use light curtains without blanking (sorry) and build fixtures that can hold the workpieces without requiring the operator to hold them. Big workpieces - you can get light curtains from ISB, Siemens, Leuze lumiflex, and elsewhere which can have a programmed sequence of beams that are allowed to be broken.

If that press is hydraulic, Z142 requires redundant monitored valves, monitored restraint devices, and control-reliable everything. It will be really, REALLY expensive.

 

[Pressed]

I can't imagine many things costing more than fingers. Light curtains and hooking them up to the machine would be the easiest and maybe the cheapest of all options. Other than that, using material hold downs (that hold on the operators command) and two palm buttons to cycle the press is an option. Palm buttons located away from feet and knees, while being separated so one arm can't trigger them.

That arm pull back device should be banned everywhere, it opens up more worms that it treats.

When I operated a brake, I always put my big foot under the bar as far as I could wedge it during alignment. Not a great solution but the plant owners weren't going to do anything to correct the hazard. Of course this was way before light curtains were even conceptualized.


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