Care &Maintenance: Protect your fitters
Page 71
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Safety regulations for the workshop can prevent injury and aid production
FOLLOWING the introduction of all manner of regulations since 1969, many old grinders and drills, especially those in smaller workshops, may be illegal — and dangerous.
Gone are the days when special pivoting eye shields could be fitted to bench grinders, and the mechanic be relied on to put the shield in place before he used the grinder. Since the liability is now on the employer, safety guards must be fixed, so that their use is not at the discretion of the mechanic.
Eye shields have been obligatory on the bench grinders that are commonly used in workshops for many years, and so they are standard equipment on all models on sale. But these shields can easily get covered with grit, and before long, one of the mechanics has removed them.
If questioned, the man will not unnaturally point out that the dirty shield makes visibility so bad that he is endangering his fingers by using it. With some of the old designs, in which a small window is held in a big metal shield, that may be the case, especially if the shield is too near the wheel.
However, the use of a frameless shield, some height above the wheel, but still positioned to give protection, should overcome this problem. In any case, the shield needs an occasional clean, just as any other piece of optical equipment.
A good example of shielding is found on the Wolf doubleended 125mm ( 5in) bench grinder normally equipped with the coarse and fine wheels required in a workshop.
If the mechanics are prone to forget to replace shields and housings after replacing worn components, it is worth while reminding them of the regula tions. As far as grinders are concerned, the main requirements are laid down in The Abrasive Wheels Regulations, 1970, the main aim of which was to prevent injury from disintegrating wheels.
The flanges that retain the wheels must be at least 1/3 diameter of the wheel, and they must be of equal size on both sides of the wheel — so don't be tempted to fit a smaller one on the outside, if the proper flange happens to be lost when the wheel is being changed.
The next important provision is that the wheel guards should be constructed so as to contain the wheel should it disintegrate. Generally, therefore, the wheels are now totally enclosed, apart from the apertures above the tool rest.
Of course, the presence of these guards does lengthen the job of renewing the wheel, but the infrequency of this job makes this unimportant.
One regulation that does make the job easier is that the tool rest must be adjustable to allow for wear of the wheels. This regulation has led to improvements in rest design, making grinding of most objects involved fairly simple.
Portable grinders and sanders also have guards over a portion of the wheel, and these are equally important.
Despite the use of compressed air tools, the portable electric drill is still a very useful tool in a workshop, and here the trend is away from 'earthed' tools to ones that are double insulated. Although the earthing system does give some protection, it can present some danger to the operator.
Since there are three wires involved, the tool can be wired incorrectly, giving the first man to use it a hefty shock. But even if the wiring is done correctly, the earth cable or even a few strands can loosen, contact the power terminal, and make the tool live.
Incidentally, according to the Chief Inspector of Factories (Electrical), many fatal accidents have resulted from the earth wire being connected to a live terminal, so the dangers should not be under-estimated.
Double-insulated tools have only two cables, a live and a neutral, so they cannot be wired incorrectly. The bodies, switch handles, and side handles are made from non-conductive materials, and on the Wolf Sapphire drills, the spindles are insulated from the chucks and gears as well. Therefore, if there is a short internally, it cannot harm the operator.
Since the system is fused. the fuse will blow, cutting out the machine. With such a machine, the only important point is to rake sure that the correct fuse is used — and that on no account should anything other than a fuse be used as a temporary measure. It also follows, of course, that if a fuse does blow, there is a fault in the tool, and this should be investigated.
Just as workshop staff must appreciate that grinding-wheel guards are an essential part of the machine, so must they recognise the importance of using guards on pillar drills.
A visit from the factory inspector usually leads to these things being put right, but the regulations are soon forgotten. Someone moves the drive belt from one pair of pulleys to another to change speed, and because he knows that the speed will need to be changed again, he leaves the cover off.
As often as not, it stays off until there is an accident or the factory inspector appears. One way over this is to incorporate a switch in the circuit so that the drill will operate only when the cover is in place. A push-button switch, similar to those used to operate the courtesy lights' in cars, is the sort of thing that is needed.
Such a device is hardly practical with the obligatory guards for chucks and the twist drills themselves. These guards are normally telescopic, to suit the lengths of standard drills. The device offered by Startnte Engineering Co Ltd, Waterside Works, Waterside Lane, Gillingham, Kent, for its drills is of a simple two-part pressed steel design, locked together by a wing nut.
This type of guard may seem a constant nuisance it makes the mechanic take a little more trouble in setting the job up, which means that greater accuracy is likely to result.
The extra care needed also means that the component to be drilled is more likely to be clamped in position properly, thus reducing the likelihood of its spinning on the drill.
But the main point to remember is that there is a purpose behind each of these regulations, however awkward they may seem — and that is to protect the workshop staff.