With some machines, articles have to go in or out.
And since you want to avoid a light curtain or similar for cost reasons, the question arises as to what sizes are allowed here. And as you might expect, the permitted openings are very small.
Again, the standard differentiates between square and slit openings.
First let's make the limits clear:
Slits over 18 cm are prohibited - they allow full-body access, according to the B standard. In the case of the slits width does not matter.
Square openings, whose side length is greater than 24 cm are also prohibited. According to the B standard, they also allow full-body access.
For rectangular openings, the longer side is taken. If it is longer than 24 cm, try the slit.
Of course, there are also specifications in the standard for round and irregular openings.
I hear very often that if the size of the opening is just within allowed parameters, that this means that a distance to the danger point of 85 cm is allowed. This is not correct!
This is only valid up to 12 cm, both for slits and for square openings. And 12 cm is really not a lot. So, we have to seriously look at what rules apply to the range between 12 and 18 cm for slots and between 12 and 24 cm for square openings.
In this intermediate range, we need to use the reach-over table, which is the table that is usually used for the height of the protective fence. This is because we are over the 12 cm that the arm fits through and smaller than the full body access. That is, the standardizers assume that you can reach into the opening with your arm and partially with your upper body.
So we look in the table for reaching over:
The range between 12 and 18 cm for slots or 12 and 24 cm for square openings requires very large safety distances. If the danger point is in a horizontal plane with the opening this table requires :
- for an opening at a height of 1.0 m from the reference plane, a distance to the danger point of 1.5 m
- for an opening at 1.2 m height from the floor, a distance to the danger point of 1.4 m
- etc.
These are quite large distances, especially since the danger point is quite common at low heights.
Of course, especially with such problematic figures, there are C standards that deviate from this. It is not surprising that the C standard for packaging machines, which always have the problem that articles have to enter the hazardous area and the packaged articles have to exit again, are somewhat more generous here with the openings and clearer in defining the safety distances, especially in the intermediate area.
Of course, you may only use the C standard for packaging machines if you really have a packaging machine. But you can pick up a few general tips from the C standard.
In some cases, it can be helpful to build tunnels into the protective casing. This will increase the distance to the hazardous area. If you also build the tunnel inwards, this can restrict the arm's freedom of movement. If, for example, the danger is caused by a traversing unit further up and not at the same height as the tunnel, you can no longer reach the danger area through the tunnel.
In addition, this C standard clearly clarifies that you may measure the height of the opening from the top of the belt leading into the opening.
So what are you trying to take away from all these numbers?
Openings for article input may not be more than 18 cm high as a slit and may not have a side length of more than 24 cm as a square.
The 85 cm safety clearance behind the article input only applies up to 12 cm. After that, the safety distances for reaching over must be used, and they go up to 1.5 m.
If you would like to purchase a standards search, you can find it at
The video, a translation of which you can see here, can be found at:
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