WO2000031502A1

WO2000031502A1 - Slope detector

Info

Publication number: WO2000031502A1
Application number: PCT/EP1999/009169
Authority: WO
Inventors: Giovanni Sala
Original assignee: Giovanni Sala
Priority date: 1998-11-24
Filing date: 1999-11-19
Publication date: 2000-06-02
Also published as: ITMI982535A1; IT1303854B1

Abstract

A slope detector (10, 30, 60) comprises a device for measuring the inclination of a vehicle with which it is associated and an electronic circuit (90) which converts the slope detected into numerical data appearing on a system of display devices (100). The inclination measuring device may be of the variable-resistance or variable-capacitance type and may be used in applications other than those on vehicles, being suitable also for a device for measuring the inclination of building surfaces, i.e. in the manner of an electronic spirit level.

Description

SLOPE DETECTOR

The present invention relates to a slope detector which can be used for reading immediately the value of the inclination which a vehicle assumes with respect to a horizontal surface in order to determine whether the vehicle is on an upward slope or downward slope and also determine, for example in a sporting context, such as cycling, the performance of an athlete in particular travel conditions. In this latter case the present invention could be of particular use in assessing the degree of fitness and/or physical recovery of athletes involved in a particular sport.

An object of the present invention is to provide a slope sensor which detects the inclination of a vehicle with respect to a horizontal line, indicating this inclination as an angle in degrees or as a percentage of upward slope (or downward slope) with respect to the distance travelled.

Another object is to provide a slope measuring device which is able to determine the inclination and perform measurements thereof on flat portions of building structures, operating in the manner of an electronic spirit level which can be directly read.

The abovementioned objects are achieved in the form of a slope detector comprising an electromechanical device indicating the inclination which a flat zone, or a vehicle resting on the ground, assumes with respect to the horizon and an electronic circuit which converts the slope detected into a reading on display devices, characterized in that it contains a weight which positions itself in any case at a minimum height inside the electromechanical device, influencing an electrical parameter which is modified when the slope is changed so as to send to the electronic circuitry signals which are able to provide a reading on the display devices. In particular the electromechanical device is of the resistive type having a resistance which, starting from a middle value, increases when the slope varies in one direction and decreases when the slope varies in an opposite direction.

Alternatively, the electromechanical device is of the resistive type having a resistance which, starting from a maximum value, decreases when there is a slope variable in one direction only. By way of a further alternative, the electromechanical device is of the resistive type which, starting from a minimum value, increases when there is a slope variable in one direction only.

Preferably, the electromechanical device consists of a resistive track, deposited on an insulating support, and a movable weight consisting of a droplet of mercury which connects the resistive track to a conducting plate arranged opposite the resistive track.

Even more preferably, the electromechanical device is formed by a casing, provided with a fixing base, the casing having a cylindrical shape defining an internal chamber, on a circular base of which the insulating support with the resistive track is arranged and on the opposite circular base of which the conducting plate is arranged, the mercury droplet being located at the lowermost point of the casing so as to ensure a connection between the resistive track and the conducting plate.

In particular, the conducting plate is connected to the exterior by means of a first connector and the resistive track is connected to the exterior by means of a second connector.

Preferably, the internal chamber of the casing is filled with a substance which is non-reactive with respect to the mercury droplet.

In particular, the non-reactive substance is a gas which is inert with respect to the mercury droplet.

Alternatively, the non-reactive substance is a liquid which is electrically insulating and inert with respect to the mercury droplet.

Preferably, the non-reactive substance is a liquid which is electrically insulating and inert with respect to the mercury droplet. Preferably, the non-reactive substance is a liquid which is electrically insulating and anti-oxidising with respect to the mercury droplet.

Alternatively, the electromechanical device is of the capacitive type formed by an insulating cylindrical casing housing internally an insulating cylindrical block which is immersed and suspended in an insulating and viscous liquid, the insulating block having two conducting armatures connected by a solid bridge, acting as a counterweight, where the cylindrical casing houses, on opposite circular faces, fixed armatures connected to the exterior by means of connectors, the set of the two armatures movable with the cylindrical block and the two fixed armatures forming a variable-capacitance capacitor, the capacitance of which starts from a middle value, increasing for a slope variable in one direction and decreasing for a slope variable in the opposite direction.

By way of a further alternative, the electromechanical device is of the capacitive type formed by an insulating cylindrical casing housing internally an insulating cylindrical block which is immersed and suspended in an insulating and viscous liquid, the insulating block having two conducting armatures connected by a solid bridge, acting as a counterweight, where the cylindrical casing houses, on opposite circular faces, fixed armatures connected to the exterior by means of connectors, the set of the two armatures movable with the cylindrical block and the two fixed armatures fomiing a variable-capacitance capacitor, the capacitance of which starts from a minimum value, increasing over a slope variable in each direction.

Furthermore, the slope detector, comprising the electromechanical device and the electronic circuitry, is characterized by the fact that the electronic circuitry comprises an input circuit which adapts the circuitry to the type of electromechanical device, whether it be of the resistive or the capacitive type, an analog/digital (A/D) converter, a pulse counter which counts the pulses, supplied by the A/D converter in a number proportional to an analog value emitted by the input circuit, and a set of display devices which visualise digits corresponding to the counts of the pulse counter and allow reading of the slope values detected. Preferably, the input circuit is provided with switching means able to choose between the use of electromechanical devices of the resistive type and the use of electromechanical devices of the capacitive type.

The characteristic features of the present invention will be defined in detail in the claims forming the conclusive part of the description thereof, while these and other characteristic features will emerge from the following description of examples of embodiment thereof, provided by way of a non-limiting example, together with the accompanying drawings in which:

- Figure 1 shows a sectioned side view of a slope sensor of the resistive type;

- Figure 2 shows a sectioned front view of the same slope sensor of the resistive type;

- Figure 3 shows a sectioned side view of a first slope sensor of the capacitive type;

- Figure 4 shows a sectioned front view of the same first slope sensor of the capacitive type; - Figure 5 shows a sectioned side view of a second slope sensor of the capacitive type;

- Figure 6 shows a front sectioned view of the same second slope sensor of the capacitive type;

- Figure 7 is a block diagram of an electronic circuit which is able to convert signals from a slope detector, associated with resistance or capacitance values, into numerical digits shown by digital display devices;

- Figure 8 is an electrical diagram of an input circuit, forming part of the abovcmentioned electronic circuit, able to use signals supplied from detectors both of the resistive and the capacitive type; - Figure 9 is an electrical diagram of an analog/digital (A/D) converter of the simple integration type;

- Figures 10A-E are graphs illustrating the functions which take place in an A/D converter according to Figure 9;

- Figure 1 1 is a logic diagram of a counter for binary code decimal (BCD) digits;

- Figure 12 is a logic diagram of a BCD code decoder for a seven-segment digit (BCD/7-segment) display device; and

- Figure 13 is a block diagram of a decimal three-digit counter which controls, via three BCD 7-segment decoders, three digit display devices of the seven-segment type. Let us consider firstly Figures 1 and 2. As can be seen in the said figures, a slope detector 10 is formed by an insulating and sealed casing 12 in the form of a cylindrical box with a diameter much greater than the height and having a base which forms a cover 13 fixed in a permanent and sealed manner with respect to the remainder of the casing 12. The cover 13 has, fixed against it, a conducting plate 14 which may be made of various materials such as stainless steel, lead, bare copper, nickel-plated copper, nickel-plated iron, an insulating board lined with pure or nickel- plated copper, such as a board for printed circuits, which is connected to the exterior of casing 12 by means of a first connector 15 which, preferably, is a metal tongue of the type for rapid-engagement (fast-on) connections. The opposite base of the casing has, mounted on it, a sheet 16 of insulating material such as a support for a resistive track 16a having a resistivity high enough to ensure, along its length, resistances of the order of about ten kilo ohms. This resistive track terminates in a connection with a second connector 17 extending towards the outside of the casing 12 with a metal tongue which is identical to the tongue which forms the conductor 15.

The casing 12 defines internally a chamber 19, the bottom of which contains a small mass or droplet 20 of mercury which ensures a contact between the resistive track 16a and the conducting plate 14, so that the assembly consisting of the second connector 17, the resistive track 16a, the droplet 20 of mercury, the conducting plate 14 and the first connector 15 fonns a rheostat or variable resistor, the resistance value of which depends on the position of the mercury droplet 20 inside the chamber 19 and therefore on the inclination of the surface on which the vehicle, in particular a bicycle, rests. In order to illustrate the operating principle of this resistive detector, reference should be made to Figure 2 which indicates, with 20,, the end position which the mercury droplet 20 would assume when the vehicle or bicycle faces an upward slope with a slope of 70% and, with 20₂, the end position which the mercury droplet 20 would assume when the vehicle or bicycle faces a downward slope with a slope of 70%. Obviously, in practical terms, the slopes which are of interest here are middle- range slopes w ith a slope of between 0% and a maximum of 20 or 30%₀. In order to ensure that there is always live contact between the mercury droplet 20 and the resistive track 16a and the conducting plate 14, the chamber 19 is filled with a liquid 22 which has the function of preventing any alteration (especially oxidation or sulphuration) of the said mercury droplet 20. The liquid 22 must be have an inert or reducing effect with respect to the mercury. For example, the liquid 22 could be ethyl alcohol, glycerine, a hydrocarbon oil, such as gasoline, vaseline oil or a silicone oil. The main properties which the liquid 22 must have are to prevent contact of the air with the mercury droplet 20 and not dissolve or in any case alter the walls of the casing 12. In any case, it would be preferable to use a liquid having a sufficient viscosity to slow down and dampen the movements of the mercury droplet 20 so as to allow it to remain always in contact with the lowest zone of the chamber 19 of the casing 12. A screw-type plug, which can be sealed in any way, closes a hole which may be used for replenishing inside the chamber 19 both the mercury droplet 20 and the liquid 22 for protecting the mercury and damping its movements.

The casing 12 is integral with a base 25 which, by means of its flanges 24 and 26 provided w ith screw-holes, can be used to fix the detector 10 to any structure of the vehicle or bicycle.

Let us now consider Figures 3 and 4. As can be seen in the said figures, a first slope detector 30 of the capacitive type is formed by an insulating and sealed casing 32 defining a cylindrical internal chamber 34 which contains a cylindrical block 36 which is also made of insulating material and which houses two metal armatures 38 and 40 which are connected together by a solid metal bridge 42, which acts as a counterweight, forcing the cylindrical block 36 to remain with the zone containing the said counterweight 42 oriented downwards. A fixed armature 44 is incorporated and fixed to a circular wall 46 of the casing 32 and another fixed armature 48 is incorporated and fixed to the opposite circular wall 50 of the said casing 32. The fixed armatures 44 and 48 are provided with connectors 52 and 54, respectively, for example in the form of the tongue of the rapid engagement or "fast-on" type. The chamber 34 is completely filled with an insulating liquid having sufficient viscosity to dampen any sudden movement of the cylindrical block 36 due to jolts or the like. Examples of liquids suitable for this purpose are: vaseline oil, a silicone lubricating oil, an insulating oil for transformers, or similar liquids.

The operating principle of this first capacitive detector 30 is as follows: Since the counterweight 42 forces the cylindrical block 36 to remain in the same direction, the effect is that, when the vehicle or bicycle on which this detector is mounted is situated on an uphill road and if the front part of the vehicle is conventionally imagined to the right, the fixed armatures 44 and 48 rotate in an anticlockwise direction with respect to the armatures 38 and 40 of the block 36, moving towards them and consequently increasing the capacitance between the fixed armatures 44 and 48 and the movable armatures 38 and 40. The slope may become such that the movable armatures 38 and 40 are located between the fixed armatures 44 and 48 and. in this case, the insulating liquid which fills the chamber 34 entirely helps in preventing accidental contact between fixed armatures and movable armatures. Obviously, these accidental contacts may be completely avoided by means of measures known per se such as an insulating film over the fixed armatures 44 and 48 or over the movable armatures 38 and 40 or, alternatively, a peripheral raised rim on the two opposite circular surfaces of the block 36. The maximum slope which can be measured is that corresponding to the situation where the fixed armatures and movable armatures are completely superimposed, which is equivalent to about 70% - a slope which is practically impossible to face. When, on the other hand, the vehicle or bicycle is situated on a downhill road, the fixed armatures 44 and 48 rotate in the opposite direction with respect to the armatures 38 and 40 of the block 36, moving away from them and consequently reducing the capacitance between the fixed armatures 44 and 48 and the movable armatures 38 and 40. The downward slope remains measurable until rotation of the armatures 44 and 48 reduces the capacitance thereof. It is reckoned, by way of a conservative estimate, that slopes of up to 70% may be measured, even though said slopes obviously cannot even be reasonably faced.

Let us consider now Figures 5 and 6. As can be seen in these figures, a second slope detector 60 of the capacitive type is formed by an insulating and sealed casing 62 defining a cylindrical internal chamber 64 which contains a cylindrical block 66 which is also made of insulating material and which houses two metal armatures 68 and 70 which are connected together by a solid metal bridge 72, which acts as a counterweight, forcing the cylindrical block 66 to remain with the zone containing the said counterweight 72 directed downwards. A fixed armature 74 is incorporated and fixed to a circular wall 76 of the casing 62 and another fixed armature 78 is incorporated and fixed to the opposite circular wall 80 of the same casing 62. The fixed armatures 74 and 78 are provided with connectors 82 and 84, respectively, for example of the tongue type for rapid engagement or "fast-on" type. The chamber 64 is also completely filled with an insulating liquid in the same manner as the chamber 34 of the abovementioned first capacitive detector 30.

The operating principle of this second capacitive detector is similar to that of the first capacitive detector, although the different arrangement of the fixed armatures 74 and 78, which are symmetrical with respect to a vertical line passing through the centre of the said detector 60, results in a minimum capacitance between the fixed armatures 74 and 78 and the movable armatures 68 and 70 when the vehicle or bicycle is situated on a flat road so that any inclination, both uphill and downhill, produces an increase in the capacitance. In this case also, the maximum slopes which may be measured are of the order of 70%o.

Let us now consider Figure 7 which shows a block diagram of an electronic circuit 90 capable of obtaining from a signal, supplied by one of the slope detectors

10, 30 or 60, a set of digital signals which are able to activate a display system or, alternatively, can be sent to a microprocessor which processes other parameters of the vehicle, such as. for example, speed and distance travelled, so as to display and/or store them in order to allow an analysis of the car or athlete's performance. The electronic circuit 90 comprises essentially an input connection 92 entering into a circuit 94 formed by amplifiers, attenuators, rectifying systems and the like, capable of converting the electrical parameter present at the input 92 into a direct voltage ranging between precise levels dependent upon the characteristics of the successive circuits. The circuit 94 supplies the direct voltage, produced at its output, to the input of an analog digital (A/D) converter 96 which converts this direct voltage into a series of pulses, the number of which, within a predefined scanning period, is proportional to the level of the direct voltage present at the output of the circuit 94. The pulses generated by the A D converter 96 are sent, via a connection 97, to a set 98 of counters which counts these pulses, supplying to a connection assembly 99 signals for a system of display devices 100 which are able to display the slope faced by the vehicle or bicycle, both uphill and downhill, in percentages or degrees, being able to distinguish optionally between uphill and downhill. A last set 102 of connections, departing from the counter 98, is able to supply digital signals to a microprocessor for the general purposes mentioned above. Figure 8 shows a special input circuit 94 suitable for receiving signals both from a slope detector 10 of the resistive type and from a detector 30 or 60 of the capacitive type. In this input circuit 94, a supply battery 104 supplies energy to a power supply unit 106 which provides all the supply voltages both for the integrated circuits via a conductor 108 and for the slope detectors 10, 30 or 60 via a conductor 1 10. The supply voltage to the slope detectors may be continuous and stabilised if the slope detector is of the resistive type; on the other hand, it must be alternating with a fairly high frequency (of the order of a 1 to 100 kHz) and with a stabilised amplitude, if the detector is of the capacitive type. Obviously an input circuit 94 which intends using both types of detector will use a stabilised-amplitude alternating supply voltage for them, having a frequency which allows correct operation of both of them. An example of a supply voltage for slope detectors of both the resistive and capacitive type could be a square wave with a stabilised amplitude of 3 volts at a frequency of 5 kHz, since both the detectors function on the principle of a voltage divider which is resistive in the first case and capacitive in the second case. In fact, in the example of embodiment illustrated in Figure 8, a two-path switch 112 has two positions, a first one, indicated by the letter R, for the resistive detectors, and a second one, indicated by the letter C. for the capacitive detectors. When the switch 112 is in the position R, the conductor 1 10 is connected via a resistor R, to the resistive detector 10 which, together with the resistor R,, forms a voltage divider able to supply a voltage dependent upon the resistive value formed between the two connectors 15 and 17 of the same detector 10 which, as already explained, depends on the slope of the road on which the vehicle or bicycle served by the same detector 10 is situated. A diode 114 has the function of rectifying the alternating voltage which is then processed by a stabilising circuit 1 16 so as to supply an analog signal with a direct voltage V, representing the slope to be measured, the stabilising circuit 116 eliminating all the transient signals due to jolts.

In a similar manner, when the switch 112 is in the position C, the conductor 1 10 is connected via a capacitor C, to the capacitive detector 30 or 60 which, together with the capacitor C,, fonns a voltage divider able to supply a voltage dependent upon the capacitive value formed between the two connectors 52, 54 or 82, 84 of the same detector 30 or 60 which, as already explained, depends on the slope of the road on which the vehicle or bicycle served by the same detector 10 is situated. A resistor 1 18 and a diode 120 have the function of rectifying the alternating voltage and causing the flow of a direct current, where the rectified voltage is then processed by the stabiliser circuit 1 16 in order to supply a direct voltage analog signal V, representing the slope to be measured.

Let us now consider Figures 9 and 10A-E which illustrate the analog/digital (A/D) converter 96 according to Figure 7 and graphs representing functions which occur inside the said A/D converter 96, respectively. This A/D converter 96 is of the type defined as "simple integration" which supplies at its output trains of pulses, within a sampling period T defined by a sampling pulse V_N2, illustrated in Figure 10B, output from a sampling device 130, having numbers of pulses proportional to the value of the continuous analog signal V,. The continuous analog signal V, is introduced into an integrator stage 132 comprising an operational amplifier 134 provided with an input resistor R for its inverting input (-

) and integration capacitor C connected between the output and inverting input (-) of the operational amplifier 134, so that the integrator 132 produces at its output a descending ramp V_u (illustrated in Figure 10E), the steepness of which is proportional to the value of the analog signal V, (illustrated in Figure 10A) entering into the said integrator 132. This ramp V_u introduced into a first input of a comparator 136 stops, within a period T. , detennined by the level of the analog signal V„ when it reaches a value equal to a reference level -V, introduced into a second input of the comparator 136 and the comparator 136 discharges the integration capacitor C via a resistor R, within a fixed period T detennined by the capacitance of the capacitor C and by the resistance of the resistor R, connected between the output of the comparator 136 and the inverting input (-) of the operational amplifier 134 present in the integrator 132, providing a rising ramp of fixed duration T_s, so that at the output of the comparator 1 6 there is a signal V_llc shown in Figure IOC. This signal N_uc enters into a pulse generator 138 which generates a train of pulses V. „ similar to the pulses shown in Figure 10D, which are supplied to an AND gate which reproduces these pulses at its output as the signal V_L for as long as the sampling signal V_x2 stays high, as illustrated in Figure 10B.

Let us now consider Figure 11 which shows a decade device 98a of a BCD digital counter, i.e. a binary code decade counter. This decade device, which has been known per se for many years, is formed by as many bistable circuits 142 to 148 as there are binary digits necessary for representing the decimal digits from 0 to 9, i.e. four bistable circuits, bearing in mind that the digit 0 is represented by the binary number 0000, the digit 9 is represented by the binary number 1001 and the digit 10, represented by the binary number 1010, must reset the same decade device 98a. As illustrated in Figure 1 1. the bistable circuits 142 to 148 are formed by integrated circuits of the type called "j-k flip-flops" which have the special feature of emitting a signal at one of their outputs y or Y for every two pulses received at one of their scanning inputs t. In order, the j-k flip-flop 142, indicated by the letter A, supplies at its output A a high or low voltage status, indicating the binary value of the least significative digit representing the first decade device, the j-k flip-flops 144, indicated by the letter B, supplies at its output B a high or low voltage status indicating the binary value of the penultimate significative digit representing the first decade device, and so on, with the flip-flop 146 representing at its output C the second significative digit and the flip-flop 148 representing at its output D the first significative digit. The same output D is also used as a carry output V_R for entering into a second counter decade device, not shown since it is identical to the first decade device 98a. The counter is reset when it reaches the tenth count owing to a NAND gate 150 which sends a reset signal to the inputs Cr of the four j-k flip-flops 142 to 148, resetting their outputs y respectively indicated by the letters A, B, C and D. Figure 12 shows a logic diagram of a conventional BCD code decoder 152a for a seven-segment digit display device to be connected between the decade device 98a of the BCD counter 98 and a seven-segment display device 154a. This decoder 152a comprises four logic inverters 156 which make it possible to have together the binary signals A, B, C and D and their logic complements indicated in the figure by the same letters with a line above. The set of four binary signals and their logic complements enter into ten NAND gates 158, the outputs of which are indicated by the decimal digits 0 to 9 and these outputs are combined in seven NAND gates so as to cause display of the corresponding digits by the seven-segment display device 154a. Figure 13 show s a three-digit decimal counter assembly formed by three decade devices 98a, 98b and 98c, where the decade device 98a receives the signal V_c from the A/D converter 96 and the decade devices 98b and 98c receive carry signals V_κ from each preceding decade device, so that the counter is able to count units, tens and hundreds. Each decade device 98a, 98b and 98c sends its four binary signals A, B, C and D to its corresponding decoder 152a, 152b and 152c which supplies signals to a corresponding display device 154a, 154b and 154c thereof.

The above description describes some embodiments of slope detectors equipped with their electronic processing circuits and with display devices which are not to be regarded as limiting in any way, since several similar and equivalent solutions ma)' occur to a person skilled in this specific art upon reading about the embodiments described above.

For example, the base 25 of Figure 2 does not have to be necessarily horizontal, but could be vertical and applied to one of the circular bases of the casing 12, it being understood in this case that the slope detector 10 would have to be fixed to a vertical structure of the vehicle or bicycle and that in any case the orientation of means for fixing the detector 10 would be of no importance, provided that the mercury droplet 20 is situated in the position shown in Figure 2 when the vehicle is on a horizontal surface. However, should it be required to construct a slope detector which indicates only the uphill slope, it would be sufficient to select a detector, similar to the detector 10, but oriented so that the mercury droplet 20 is situated at the far end of the resistive track 16a when the vehicle is on a flat surface.

Again, the specific electronic circuits which are shown here are not binding and are provided only by way of example of circuits which are able to equip the slope detectors illustrated here. Finally one of these devices could be used as an electronic spirit level which is able to provide a direct reading of desired inclinations of floors or terraces to be used in the building sector.

Claims

1. Slope detector comprising an electromechanical device (10, 30, 60) indicating the inclination which is assumed, with respect to the horizon, by a flat surface or a vehicle resting on the ground and an electronic circuit (90) which converts the slope detected into a reading on display devices (154), characterized in that it contains a weight (20, 42, 72) which positions itself in any case at a minimum height inside the electromechanical device (10, 30, 60), influencing an electrical parameter which is modified when the slope is changed so as to send to the electronic circuitry (90) signals which are able to produce a reading on the display devices ( 154).

2. Slope detector according to Claim 1, characterized in that the electromechanical device (10) is of the resistive type having a resistance such that, starting from a middle value, it increases when the slope varies in one direction and decreases when the slope varies in an opposite direction.

3. Slope detector according to Claim 1, characterized in that the electromechanical device (10) is of the resistive type having a resistance which, starting from a maximum value, decreases when there is a slope variable in only one direction.

4. Slope detector according to Claim 1, characterized in that the electromechanical device (10) is of the resistive type having a resistance which, starting from a minimum value, increases when there is a slope variable in only one direction.

5. Slope detector according to Claims 2 to 4, characterized in that the electromechanical device (10) consists of a resistive track (16a) which is deposited on an insulating support (16) and in that a movable weight consists of a mercury droplet

(20) which connects the resistive track (16a) to a conducting plate (14) arranged opposite the resistive track (16a).

6. Slope detector according to Claim 5, characterized in that the electromechanical device (10) is formed by a casing (12) provided with a fixing base (25). the casing (12) having a cylindrical shape defining an internal chamber (19). on one circular base of which the insulating support (16) with the resistive track (16a) is arranged and on the other opposite circular base of which the conducting plate (14) is arranged, the mercury droplet (20) being positioned at the lowest point of the casing ( 12) so as to ensure a connection between the resistive plate (16a) and the conducting plate (14).

7. Slope detector according to Claim 6, characterized in that the conducting plate (14) is connected to the exterior by means of a connector (15) and the resistive track (16a) is connected to the exterior by means of a connector (17).

8. Slope detector according to Claims 6 and 7, characterized in that the internal chamber (19) of the casing (12) is filled with a substance which is non- reactive with respect to the mercury droplet (20).

9. Slope detector according to Claim 8, characterized in that the non- reactive substance is a gas which is inert with respect to the mercury droplet (20).

10. Slope detector according to Claim 8, characterized in that the non- reactive substance is a liquid which is electrically insulating and inert with respect to the mercury droplet (20).

11 . Slope detector according to Claim 8, characterized in that the non- reactive substance is a liquid which is electrically insulating and anti -oxidising with respect to the mercury droplet (20).

12. Slope detector according to Claim 1, characterized in that the electromechanical device (30) is of the capacitive type fom ed by an insulating cylindrical casing (32) housing internally an insulating cylindrical block (36) immersed and suspended in an insulating and viscous liquid, the insulating block (36) having two conducting armatures (38, 40) connected by a solid bridge (42), acting as a counterweight, where the cylindrical casing (32) houses on opposite circular faces

(46. 50) fixed armatures (44, 48) connected to the exterior by means of connectors (52, 54), the set of the two armatures (38, 40) movable with the cylindrical block and the fixed armatures (44. 48) fomiing a variable-capacitance capacitor, the capacitance of which starts from a middle value, increasing for a slope variable in one direction and decreasing for a slope variable in the opposite direction.

13. Slope detector according to Claim 1, characterized in that the electromechanical device (60) is of the capacitive type formed by an insulating cylindrical casing (62) housing internally an insulating cylindrical block (66) immersed and suspended in an insulating and viscous liquid (64), the insulating block (66) having two conducting amiatures (68, 70) connected by a solid bridge (72), acting as a counterweight, where the cylindrical casing (62) houses on opposite circular faces (76, 80) fixed amiatures (74, 78) connected to the exterior by means of connectors (82, 84), the set of the two armatures (68, 70) movable with the cylindrical block and the fixed amiatures (74, 78) fomiing a variable-capacitance capacitor, the capacitance of which starts from a minimum value, increasing for a slope variable in each direction.

14. Slope detector according to the preceding claims, comprising the electromechanical device (10, 30, 60) and the electronic circuitry (9), characterized in that the electronic circuitry (90) comprises an input circuit (94) which adapts the circuitry (90) to the type of electromechanical device (10, 30, 60), whether it be of the resistive or capacitive type, an analog-digital (A D) converter (96), a pulse counter (98) which counts the pulses supplied by the A/D converter (96) in a number proportional to an analog value emitted by the input circuit (94), and a set (100) of display devices which visualise digits corresponding to the counts of the pulse counter (98) and allow reading of the slope values detected.

15. Slope detector according to Claim 14, characterized in that the input circuit (94) is provided with switching means (112) which are able to choose between the use of electromechanical devices (10) of the resistive type and the use of electromechanical devices (30, 60) of the capacitive type.