Hi

New piece of equipment to me in food manufacturing industry. Weighchecker post metal detector. It has a pneumatic reject ram that activiates when product is either too low or too heavy. The ram is inside a metal casing structure but has no protection to the front side nor rear side so allowing a person to place their hands/arms inside and be struck by the RAM action. This would cause a crush injury to the arm against the surface of the housing of the RAM unit. I think it operates at approx 6psi (but have to check) but i do not think you can stop the action once started. Any checks i do on supplier websites have the equipment presented to same guarding arrangements as we have.

I'm trying to assess if there realistic need to review implementation of a distance guard at each side of the equipment that is also interlocked. My problem is quantifying the serverity of any injruy caused by the equipment and if it the costs to do so across many items of equipment is justified.

Just to clarify that last statement, we will cost it and we will review as part of the hierarchy approach. But where i'm unsure is if the ram has the potential to cause actual injury if struck by it. There is no information relating to this in the O&M Manual for the equipment and as I said, a new CE Marked equipment is exactly the same design and controls.

Cheers

safetyman - best to check first with the manufacturer and/or suppliers. From a quick skim through what you've described it's possible that the ram system may have insufficient force to cause significant injury and/or is designed to be safe, e.g. incorporates a component intended to break, release pressure or stop/reverse the ram movement if it encounters significant resistance. Nowadays electrically operated windows in vehicles and electrically/hydraulically powered doors in buildings tend to have such systems to prevent injury to people, including children, who unwittingly or deliberately impede their movement.

If doubt remains about whether or not the ram is designed to operate safely without guarding, perhaps because reliable information cannot be obtained from the makers/suppliers, it could be tested with a length of rolled-up newspaper to simulate a hand or arm inserted in its path. It’s important to stress that this method is a crude one (occasionally seen/used during my HSE days) and should only used with the consent and preferably presence of the factory engineer/s responsible for the machinery involved.

Also the description of the ram reminds me of a story I heard some years ago about a similar device in a cereal factory which checked the weights of cartons after they had been filled and sealed. Occasionally a carton was found to be underweight and got pushed off the process line. Some time after a new employee was engaged to work somewhere near the device, it was found that she diligently picked up the rejected cartons and put them back on the line. As nobody had thought to explain to her the purpose of the device, she thought that the cartons which occasionally landed on the floor had somehow fallen off the process line!

By their nature I reckon carrots as mentioned by Phillips are better for simulating human fingers than lengths of rolled-up newspaper. However, I think I saw and used newspaper mainly because it was much more readily available than carrots. Also, newspaper can be rolled up to form test pieces which are notably longer than carrots and thus have the advantage of keeping whoever holds them well away from potential danger areas. However, unless extra long carrots (of the sort which win prizes at flower shows) are available, it’s possible that suitably long implements can be devised to enable carrots used as test pieces to be held with a reasonable degree of safety.

Also, perhaps my recollection of the 1970s Monty Python sketch in which different types of fresh fruit were used as offensive weapons underlies why I can wildly envisage a future British Standard regarding the use of different vegetables and fruits for safety testing purposes. It could include details about why some types are better than others and also within which parameters regarding their weight and dimensions, etc. Mind you, as an internet search will confirm, specialist machines (chicken guns/cannons) are used to hurl dead chickens at high speed for testing the resistance of aircraft windscreens and jet engines against airborne bird strikes. However, the old fable about a frozen chicken being wrongly used for such a purpose somewhere with catastrophic results is evidently no more than an amusing fable! :-)