This invention relates to preventing risks generated by vibrations being inherent to the use of some tools and to which operators and users of such tools are exposed. The subject tools include boring machines, rock drills, hewers, chain saws and other similar manual devices.

Any tool is characterized by its own vibration level V expressed in m/sec ² . The use of a tool for a period of time t during a working day of T hours results in the operator being exposed to a dose of daily vibrations of:

if V = 4 m/sec

t = 4.5 hours

T = 8 hours

D = 3 m/sec ²

Prevention comprises integrating all the vibration doses an operator undergoes or is exposed to during one day and ensuring he does not receive more than a maximum A (8), being fixed as 5 m/sec ² at the present time, notifying him when such a maximum is reached .

The integral of the doses occurs as a rule extracting the square root from the sum of the squares of such doses.

Today, an operator is provided with a dosimeter, to be mounted on the tool that he intends to use so as to detect the own vibration of the tool V, to determine the exposure duration t, to calculate the vibration dose D and to store such a dose. If the operator uses several tools, he cannot grasp the dose integral .

This invention provides a dosing system of a simpler implementation, with a personal strap an operator can keep on his wrist while using his work tools .

Thus, this invention relates to a vibration dosing system for a tool an operator using the tool is exposed to, comprising:

^■ on the tool, a RFID tag with an electronic identification chip containing the own vibration level of the tool and an RF emitter for transmitting such a level, and

■ a strap with means for receiving a vibration level, means for determining a vibration exposure duration, means for determining the corresponding vibration dose and means for integrating a plurality of doses.

The system of this invention is a good indicator of vibrations, or dosimeter, easy to be implemented. The strap is worn on the wrist and conventionally cooperates with a RFID tag. By the way, it should be reminded that the RFID abbreviation is used for referring to radiofrequency identification. Each time a tool provided with a chip is exchanged, dosing is carried out by the operator's strap.

Should the operator use a tool without a tag, the operator manually records the value of the vibrations in the tool. In the absence of a manual recording, the means for receiving the vibration level from the strap are arranged for adopting the maximum level of vibrations. The strap could comprise detection means for an identification tag so as to control activation means for its other receiving, determining and integrating means. However, this arrangement is not easy to be implemented.

Preferably, controlling the activation means is delayed by a predetermined period so as to avoid taking into consideration the manual vibrations of the strap wearing wrist.

This invention will be better understood reading the following description of a preferred embodiment of the dosing system of this invention, referring to the appended drawing, wherein:

Fig. 1 shows the dosing system of this invention, with its RFID tag on the tool and its strap on the operator's wrist;

Fig. 2 shows the system of Fig. 1, being in operation; and

Fig. 3 is a block diagram of the components of the strap.

The tool of Fig. 1 is here a rock drill 1 onto which a RFID tag 2 has been arranged, wherein there are integrated an electronic chip and a RF emitter intended for transmitting to a matching receiver with the tag - in the present case, that of the strap-dosimeter to be further detailed herein after - the own vibration level of the drill.

The operator who is going to use the tool 1 wears on his wrist 3, a strap-dosimeter 4. The dosimeter as such is a small housing 5, fastened on the strap (it could be integrated into it), comprising a plurality of components arranged around a microprocessor (μΡ) 6. Connected by a bus 7-9 to such a microprocessor 6, there are (Fig. 3) :

^■ an (waking) activation member 11 for the components of the housing 5;

" a delay line 12 connected to the activation member 11, for delaying the effect of the activation member 11 so as to avoid having to take into consideration the natural vibrations of the strap wearing wrist;

" a receiver 13 for receiving from a RFID tag the own vibration level of a tool, connected to the delay line 12;

^■ a counter 14, connected to the delay line 12 and to a clock 15, for determining the period of time during which the strap-dosimeter 4 wearer is going to be exposed to vibrations;

^■ a calculator 16, connected to the delay line, for determining the vibration dose an operator using a determined tool is exposed to;

" a calculator 17 for integrating doses received by an operator, also connected to the delay line 12; and

^■ a display screen 18, as signalling means, with, here, a control button (C) 19 for selecting data to be displayed.

A general on/off button 20 is here also provided on the housing 5.

It shall be noticed that, on Fig. 2, and for mere simplicity, the picture appearing on the screen 18 of the housing 5 is rotated by 180°.

In the case being shown, the own level of vibrations of the tool 1 to be used is 18 m/sec ² , such as displayed on the screen 18. On the screen 18, on Fig. 2, the tool is being used and there is also displayed on the screen 18 the already elapsed exposure duration, i.e., 25 minutes and 31 seconds.

As a general and important note, reference is made to components arranged around the microprocessor 6 of the dosimeter.

It is understood that this is a merely functional and not structural presentation. Indeed, a lot of such "components" could be integrated into the processor itself.

The screen 18 could be also provided with a light warning, for example, with a diode.

As far as the clock 15 is concerned, it actually organizes the operation of the whole housing 5.

An identification tag detector could be provided for controlling the activation member 11. But this arrangement would be difficult to be implemented because of

radiations from the antennas of the identification tags and of the dosimeter,

the sizes of the antennas, the electromagnetic pollution of the tool engines, and

the weight of the required batteries .