IMPROVED STRUCTURE OF BRAKE TESTER PLATE DESCRIPTION

Field of the invention The present invention relates to the field of industrial plants used for verification tests on the braking force of vehicles and, in particular it relates to a measurement system of the braking force comprising a platform brake test bench that can be arranged on the floor, or mounted to a vehicle lift.

Description of the prior art

As well known, a brake test bench is an apparatus for measuring the braking force, the braking efficiency, and, in certain cases, other parameters of vehicles of different kinds. The brake test benches are now common in the garages and in the service centres where necessary tests are carried out for the compulsory periodic overhaul of vehicles circulating on road.

Different types of brake test benches exist and precisely the roller brake test, more common, and the platform brake test.

In particular, a roller brake test consists of a box ^¬ like structure, normally built in the floor, provided with two couples of rollers opposite to each other that surface at the upper side of the structure through fitting apertures. These apertures, from which the rollers surface, are spaced from each other by a central area that defines a space where the means for actuating the rollers are typically arranged. The vehicle to be tested is positioned with a couple of wheels of a same axle at the apertures, in such a way that the tyre of the wheels slidingly contact with a respective couple of rollers. By a movement system of the rollers a running condition of the wheels is obtained at a predetermined speed. In these working conditions a braking step is, then, carried out, in such a way to measure typical parameters of the braking device such as the efficiency, the weight and the force.

Another type of brake test bench similar to the above and equipped with rollers is disclosed in DE20320215. Also in this case, the vehicle is arranged with the wheels on a moving device which simulates a running condition, and as moving device of the wheels, instead of the rollers, a tapis roulant is used.

Both in the case of a roller brake test and in case of a tapis roulant brake test, the test is not realistic because the vehicle is mounted still on the brake test bench and then the moving device moves the rollers, or the tapis roulant, simulating the running condition. In both cases the test does not end with the actuation of the brakes of the vehicle, and the test can last even a very long time, i.e. until the rollers, or the tapis roulant, are operated.

Both the roller brake test and the tapis roulant brake test are adapted to measure the duration of the braking device rather than to carry out a periodic control of the braking device of a vehicle, i.e. for the service of the vehicle. This because with these types of brake test benches information are obtained on all the wheels of a same axle and it is not, therefore, possible to have precise data related to the braking efficiency of each wheel of the vehicle. Another type of brake test bench for vehicles is the "plate" type, or platform, brake tester. Differently from the above described types with rollers or tapis roulant, in the case of plate brake tester the vehicle to be tested is moved at a speed of about 10 km/hr and then the braking device is operated. Then, this test is much more realistic with respect to the tests carried out with the testers having rollers, or tapis roulant. In particular, using the plate brake tester, when the braking is made, there is a transfer of load from the front axle to the rear axle that corresponds to what really happens on the road. Therefore, the test carried out on the plate brake tester is realistic and therefore more reliable with respect to other types of brake tester.

The braking force is determined contemporaneously to the mass i.e. to the weight of each wheel, and, in case, to other parameters of the vehicle, by means of special detection devices, for example one, or more load cells, which are arranged below the platform, or brake sensors. The data are, then, processed for obtaining the main parameters and for constructing the graphs of interest like load and braking force vs. time.

In order to optimize the space available in the garages, the plate, or platform, _, brake tester, can be installed on auto lifts, for example of the type with scissors provided with one, or more hydraulic pistons for arranging the auto lift between a raised position, and a lowered position. More in detail, the auto lift is usually installed in a hole made in the floor of the garage, in such a way that when the auto lift is arranged in the lowered position it remains substantially at a same level of the floor of the room that houses the auto lift. Therefore, in this operating configuration it is possible to use the auto lift as platform brake tester. In other cases, instead, the auto lift is not provided and the structure of brake tester is arranged in the hole or installed on the floor. In the first two cases the upper surface, or support plane, of the brake tester is arranged substantially at a same height of the floor of the room in which it is installed, in the last case the brake tester has rising and descending ramps. The plane support is associated with brake sensors and/or load cells for measuring the forces acting on the plane support during the test.

With respect to the brake tester with rollers, or tapis roulant, , the plate brake tester allows, in a single test, to obtain data related to the efficiency and to the braking force of all the axles of the vehicle. This avoids to repeat the test for each axle of the vehicle with a saving a lot of time, especially in case of vehicles with many axles, for example 18 axles. Furthermore, the data determined with a plate brake tester are more reliable with respect to the other types of brake tester, because, as described above, the data are not collected through a simulation of the running condition, but during a real running condition.

However, since it is not possible to precisely foresee in which zone of the plate each wheel of the vehicle will stop, the plate brake testers are equipped with a plurality of detection sensors, each of which sends a plurality of data of force to a same central control unit.

This, in the known plate brake tester, generates a large number of data buses that are transmitted through one, or more channels of transmission. This makes highly difficult both the transmission and the processing of the data for the few number of valid readings in the short time of execution of the test (for example 100 milliseconds) .

This technical problem is not felt in the brake testers with rollers and tapis roulant, , because, in this case, the duration of the test rests on the discretion of the operator.

In addition, in case of long vehicles, in particular with a number of axles higher than 2, with the known brake tester it is not possible to measure the braking force of all the axles of the vehicle in a single test. In fact, normally, the brake testers of prior art do not have more than 4 measuring plates, split into two rows, i.e. two measuring plates arranged at the wheels of the right side of the vehicle and two arranged at the wheels of the left side of the vehicle same. This because, the higher is the number of axles of the vehicle to submit, at the same time, to the checking test of the braking efficiency, the more the above described technical problem is felt. In fact, the higher the number of axles to be measured, the higher and more complex is the number of the data buses to manage, i.e. to transmit and to analyse. Therefore, the known plants have a low number of plates because a higher number would not ensure, in any case, to obtain reliable results .

Therefore, for measuring the braking force and efficiency of all the axles of a long vehicle, such as an articulated lorry, it is necessary to repeat the test up to a complete check of all the axles of the vehicle.

More precisely, it is necessary to repeat the operation ascertaining that at each test the wheels of the tested axles are arranged at the used measuring plate. Traditionally this is obtained by a visual stop signal, stop-lights or other, which are activated when the wheels subject to the test are reach the measuring plates. Such a system, however, has clear problems because a driver must, at the right time, operate the brake of the vehicle, and this simultaneous operation has great difficulties for long vehicles having more axles. Such operation is usually, therefore, repeated a lot of times with subsequent high loss of time to complete the measurements.

Summary of the invention

It is then a feature of the present invention to provide a improved structure of a multiplate brake test bench for overcoming the above described drawbacks of the brake test benches of prior art.

This and other objects are achieved by an improved structure of plate brake test bench, according to the invention, for measuring the braking force and the braking efficiency of a vehicle, said structure comprising:

- a measuring platform comprising at least a first and a second row of measuring plates arranged one parallel to each other, each measuring plate of said first and of said second row being equipped with a respective support surface, in particular said measuring platform arranged to be crossed, during a test, by at least one vehicle arranged to advance on said brake test bench and to stop its run at said measuring plates;

- a measuring unit integral to each measuring plate of said platform, said measuring unit configured to measure the vertical forces and/or horizontal forces acting on the support surface of the respective measuring plate, said measuring unit being associated with a plurality of measuring devices comprising:

- at least a first measuring device arranged on a first side of the respective measuring plate, in particular the inlet side of the wheel of the vehicle on the plate, said first measuring device configured to measure a first flow of data of force;

- at least a second measuring device arranged on a second side of the respective measuring plate, in particular the outlet side of the wheel of the vehicle from the plate, said second measuring device configured to measure a second flow of data of force, said second side being opposite to said first side; and whose main feature is that each measuring unit furthermore comprises a dedicated control unit equipped with a microprocessor and with a local memory unit, said microprocessor being arranged to:

- receive said first and said second flow of data of force, respectively, from said first and from said second measuring device of the corresponding measuring plate ;

- process said first and said second flow of data of force;

said memory unit arranged to store said first and said second processed flows of data of force.

This particular technical solution solves the problem of the brake tester of the state of the art, i.e., to transmit and process a large number of data in a short time, even in 100 milliseconds, because it allows to locally receive the measured data at each plate avoiding the need to send at the same time to the control unit all the data that are measured on each plate.

Advantageously also an activation device is provided arranged to operate said measuring unit to start said measurement of the vertical forces and/or the horizontal forces acting on the support surface of said platform.

In particular, the activation device can be of optical type, for example a photocell. For example, the activation device of optical type can be installed at, or near to, the measuring platform.

Alternatively, the activation device can coincide with at least one measuring device of said plurality of measuring devices. For example, the activation device can be the measurement device mounted toto the measuring plate that is crossed first, in use, by said vehicle.

In particular, with respect to the prior art, the present invention makes it possible to optimize the collection of the data of force measured by the measuring devices and the processing steps of the same. In fact, the data are firstly sent by each measuring device to a dedicated control unit that provides to store them and, accordingly, then, at the end of the test, sent to a central control unit, alternatively, a PC, relieving then the overall flow of transmitted data.

In particular, each row of plates consists of at least a first and a second measuring plate.

Advantageously, each row of plates consists of a number n of plates, with n set between 2 and 36, in particular between 2 and 18.

Preferably a synchronization device is furthermore provided arranged to synchronize all the dedicated control unit of the different measuring plates of the brake tester, or in any case, a preselected part of them. This way, all the measuring devices involved in the measurement of the braking efficiency of the vehicle pass In a synchronized way, in particular at the same time, to a listening status, i.e. a start status of the detection of the data of mass and force. In other words, all the measuring devices start an acquisition step of the data of force. When the acquired data of force is higher than a low threshold value F* is, then, started in a synchronized way a detection step of the data of mass and force that are sent and recorded in said dedicated control unit.

The low threshold value of force F* corresponds, advantageously, to the value of the mass of the vehicle. This way, it is avoided that the measuring devices can start the detection step before the vehicle is positioned on the brake tester. Alternatively to the detection of the mass, the start status of measurement, i.e. the "START", can be activated with a photocell, or other systems.

Advantageously, at least one among the first and the second measuring device comprises at least one first and at least one second measuring member configured to measure the vertical force and/or the horizontal force acting on the support surface during the test for measuring the braking efficiency of the vehicle.

In particular, each measuring member, or some of them, can be a biaxial force sensor configured to measure both the horizontal forces F and the vertical forces P acting on the support surface of the measuring plates during the measuring test of the braking force of the vehicle.

Advantageously, the measuring devices of each measuring plate communicate with a respective dedicated control unit at a same plate through a connection selected from the group consisting of:

- wired connection;

- wireless connection.

According to another aspect of the invention, a method for measuring the braking force of a vehicle comprises the steps of:

- arranging a measuring platform comprising at least a first and a second row of measuring plates, each measuring plate being equipped with a respective support surface crossed by at least one wheel of said vehicle during a test;

- measuring the vertical forces and/or the horizontal forces acting on said measuring plates caused by the movement and the following braking of said vehicle at the respective support surfaces, said measuring step comprising the steps of:

- detection for each measuring plate of a first flow of data of force by a first measuring device arranged on a first side of said measuring plate;

- detection of a second flow of data of force by a second measuring device arranged on a second side of said measuring plate, said second side being opposite to said first side;

- sending said first and said second flow of data of force from said first and said second measuring device of said measuring plate to a dedicated control unit at a same measuring plate, said control unit comprising a microprocessor and a memory unit;

- processing by said microprocessor of said first and of said second flow of data of force;

storing said first and said second flow of data of force in said memory unit.

Preferably a step is, furthermore, provided - of synchronizing the onset of a listening mode of all the dedicated control unit, in such a way that the different measuring devices are adapted to dispose themselves in a listening mode at the same time.

In particular, with the expression "listening mode" a status is intended in which the different measuring devices are able to start a detection step of the forces acting on the support surface obtaining respective data force. The detection of the forces acting on the plane support and necessary for determining the braking force and the braking efficiency of the vehicle is, then, started once the measured force is higher than the predetermined low threshold value F* as described above.

According to another aspect of the invention, the improved structure of brake tester, as described above, is mounted to an auto lift.

According to a further aspect of the invention, an improved auto lift comprises:

- a support platform having a plane support on which, in use, said vehicle is arranged, said auto lift arranged to move from a lowered configuration, in which said plane support is arranged substantially at a same height of the floor of the room in which it is installed, and a raised configuration in which said plane support is arranged at a predetermined height from the floor of the room in which it is installed;

- a safety barrier arranged to pass from an access position on said support platform, when said auto lift is in said lowered configuration, in which said safety barrier is arranged below, or substantially at a same height, of said plane support and is not overlapped to it, in such a way to allow said vehicle to pass on said support platform, to a blocking position, when said auto lift is in said raised configuration, in order to prevent said vehicle from withdrawing beyond a predetermined position;

- actuation means arranged to cause the movement of said safety barrier from said access position to said blocking position, when said auto lift passes through from said lowered configuration downwards to said raised configuration, and the movement of said safety barrier from said blocking position to said access position, when said auto lift passes from said raised configuration to said lowered configuration;

whose main feature is that said actuation means provides at least one actuation arm having:

- an embracing portion at which said actuation arm is pivotally connected to said auto lift about a rotation axis, in particular substantially parallel to said support platform; an actuation portion at which said actuation arm is constrained to said safety barrier and exerts on it a lifting ( F _so ii) /lowering (Fabb) thrust;

- a first application portion of a first force Fl by an actuation member, said actuation member arranged to exert a force Fl configured to cause a rotation of said actuation arm in a first rotation direction, said rotation in said first rotation direction generating a force Fsoii on said safety barrier at said actuation portion that causes the movement of said safety barrier from said access position to said blocking position when said auto lift is in said raised configuration;

- a second application portion of a second force F2, said second force F2 being a constraining force of reaction exerted by a reference surface when, during the movement of said auto lift from said raised configuration to said lowered configuration, the second application portion is in contact with said reference surface, said second force F2 being configured to exceed said first force Fl and to cause, therefore, a rotation of said actuation arm in a second rotation direction R2 opposite to the first rotation direction, said rotation in said second rotation direction R2 adapted to generate a force Fabb on said safety barrier at said actuation portion that starts the movement of said safety barrier from said blocking position to said access position. Brief description of the drawings

The invention will be now shown with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

- Fig. 1 diagrammatically shows a perspective view of an improved structure of brake test bench for measuring the braking force of a vehicle, according to the invention;

- Fig. 2 diagrammatically shows in a perspective view an exploded configuration of the main electronic components of which the measuring plates of Fig. 1 are equipped with;

- Figs. 3 to 5 diagrammatically show in a perspective top plan view some possible exemplary embodiments provided for the measuring plates, according to the invention;

- Figs. 6 to 9 diagrammatically show perspective views of some exemplary embodiments provided for the brake tester, according to the invention;

- Fig. 10 diagrammatically shows a structure of brake test bench according to the invention, in operating conditions ;

- Fig. 11 shows a block diagram which shows the main steps of the method according to the invention for measuring the braking efficiency and the braking force of a vehicle;

- Fig. 12 shows a block diagram which shows the main steps of the method according to the invention for measuring the braking efficiency and the braking force of a vehicle according to a different embodiment with respect to the case shown in Fig. 11;

- Fig. 13 diagrammatically shows an elevational side view partially cross-sectioned, of an auto lift, according to the invention, in the lowered configuration;

- Fig. 14 diagrammatically shows the auto lift of Fig. 13, in an elevational side view partially cross- sectioned, in the raised configuration;

- Fig. 15 shows in a perspective top plan view the auto lift of Fig. 13 in the lowered configuration;

- Figs. 16 to 18 diagrammatically show the safety barrier, according to the invention, for highlighting some technical features in three different positions and precisely in an access position to the support platform of the auto lift, in a blocking position, and in an intermediate position, in which it exerts the lowering force F _a b on the safety rod;

- Fig. 19 shows in a perspective top plan view the auto lift of Fig. 1 in the raised configuration;

- Figs. 20 and 21 diagrammatically show an exemplary embodiment of the safety barrier of Figs. 16 to 18 in an access position, and in, a blocking position, respectively .

Detailed description of some exemplary embodiments

In Fig. 10 an improved structure is diagrammatically shown of brake test bench 100, according to the invention, for measuring the braking force, and in case, other parameters, for example the braking efficiency, of a vehicle 50.

The structure of brake test bench 100 has a platform 10 comprising at least one first row 24 and a second row 24' of measuring plates 20 arranged parallel one to the other. More in detail, each row 24, or 24', comprises a predetermined number of measuring plates. For example, a solution with 18 measuring plates 20 allows to carry out the test on very long vehicles 50, for example vehicles with 5 axles 151-155 as diagrammatically shown in Fig. 10, but also vehicles 50 having more than 18 axles. This way, it is possible to measure the force and the braking efficiency of all the wheels of the vehicle 50 only in one time having then the reliability to have correctly executed the test.

Each measuring plate 20 has a respective support surface 25 crossed, in use, i.e. during a test, by at least one wheel of a vehicle 50.

Normally, the support surface 25 is arranged substantially at a same height of the floor of the room in which the structure of brake test bench 100 is installed, for example a garage. This is obtained, usually, installing the platform 10 in a hole 200 made in the floor of the room. In a particular solution provided, the brake test bench 100 can be mounted to an auto lift 1 provided with a support platform 16 having the plane support 15, in such a way that both the devices can be used, i.e. the brake test bench and the auto lift 1 occupying a minimum space in the garage. Such a solution is, for example, diagrammatically shown in Fig. 8. The measuring unit 60 comprises, moreover, a second measuring device 62 arranged on a second side 22 of the measuring plate 20, i.e. at the opposite side with respect to said first side 21.

During a test for measuring the braking force of the vehicle 50, each measuring device 61, or 62, is adapted to measure the vertical forces P and/or the horizontal forces F acting at the respective side 21, or 22, of the measuring plate 20.

According to the invention, each measuring unit also comprises a dedicated control unit 30 equipped with a microprocessor 31 and of a memory unit 32. More in detail, the dedicated control unit 30 is configured to receive the first and the second flow of data of force 121 and 122 by the measuring devices 61 and 62 of the respective measuring plate 20. The first and the second flow of data of force 121 and 122 are, then, processed by the microprocessor 31 and stored in the memory unit 32. The particular solution used by the present invention makes it possible to optimize the time and the speed for controlling the measured data of force by each measuring device. In fact, the data are firstly sent by a single measuring devices 60 to a local control unit 30 that provides to process and to store the same. The processed data are sent by each local contro unit 30 to a central control unit 300 through a dedicated channel. This way, the transmittion of the measured data is simplified and speeded up.

Higher is the number of the measuring plates 20 of the brake test bench 100 more felt is this problem for the increasing in the amount of measured, processed and transmitted data.

The structure of brake test bench 100 also comprises an activation device 80 arranged to activate the measuring unit 60 in a predetermined moment, i.e. when the vehicle 50 crosses the first plate of the platform, or when it is located near the same. More in detail, the activation device 80 operates the measuring unit when starting the measurement step of the vertical forces and/or horizontal acting on the surface of the platform.

In a possible exemplary embodiment, diagrammatically shown in Fig. 6, the activation device 80 can be of optical type and comprises at least one photoelectric sensor, or a photocell. For example, the activation device 80 of optical type, in the case of Fig. 6 the projector 85a and the receiver 85b of the same, can be installed at, or near to, the measuring platform of the brake test bench structure 100.

Alternatively, the activation device 80 can coincide with at least one of the measuring devices of the above described plurality of measuring devices of which the brake test bench 100 is eguipped with. For example, the activation device 80 can coincide with the measurement device 61, or 62, mounted to the measuring plate that is crossed first, in use, by said vehicle.

The homologous measuring plates 20 and 20', i.e. the measuring plates arranged, on respective row 24a and 24b, positions corresponding to a same axle of the vehicle 50 can be used for measuring the braking force of the wheels belonging to a same axis. This way, in a single passage it is possible to measure the braking force of all the wheels of the vehicle. This allows to avoid to repeat the operation for each axle of the vehicle 50 as it is carried out in the apparatus of the state of the art. This way, not only the time is reduce for finishing the measurement of the braking efficiency of all the wheels of the vehicle, but the risk is also reduced to make errors during the detection step. In fact, in order to determine the braking force of the vehicle it is necessary to have comparable data, i.e. measured in similar conditions, in particular of speed.

As well known, with the presently known apparatus it is necessary to repeat the operation for each axle checking that for each test the wheels of the tested axle are arranged at the used measuring plate. Traditionally this is obtained by an operator who communicates to the driver of the vehicle when this is arrived at the measuring plates. Such system, however, has clear problems because not only the operator must communicate with timing to the driver of the entering on the measuring plate, but the driver must also timing operates the brake of the vehicle. Such operation is, therefore, usually repeated many times with consequent high loss of time for finishing the measurement. An alternative provides to equip the apparatus with suitable sensor with consequent high costs.

In the exemplary embodiment of Fig. 3, the measurement device 60 provides a measuring device 61 at the side 21 of each measuring plate 20 and two measuring devices 62a and 62b at the side 22.

In the exemplary embodiments of Fig. 4 and 5, instead, the measurement device 60 provides both two measuring devices 61a and 61b at the side 21 and two measuring devices 62a and 62b at the side 22 of the plane support 25.

Preferably, each measuring device 61a, 61b, 62a, 62b used is a biaxial force sensor and is, therefore, able to measure both the vertical forces P and the horizontal forces F acting on the plane support 15 during the test for measuring the braking force of the vehicle 50. In general, the number of measuring devices, or sensors, that are used depends on the desired level of accuracy and on the will, or not, to have abounding measurements.

Therefore, the platform 10 comprises a plurality of measuring plates 20 arranged in at least two rows 24a and 24b each of which comprising a predetermined number of measuring plates 20. Therefore, the platform 10 consists of a number of plates set between 4 and 36 each of which defines a respective portion of the plane support 15.

In Fig. 12 the main steps are diagrammatically shown of the method for measuring the braking force of a vehicle 50, according to the invention. In particular, the method provides a starting step of detecting the vertical forces P and/or the horizontal forces F acting on each measuring plate by moving and then braking the vehicle at the respective support surfaces obtaining a number n of flows of data of force, block 401. In particular, each measuring plate has at least a first and a second measuring device arranged at opposite sides of the plate same. Each measuring device detects the data of force and delivers a corresponding measured flow of data to a control unit dedicated to the measuring plate, for example mounted to the plate same, obtaining n flows of measured data, block 402. Each dedicated control unit comprises a microprocessor configured to process the data of force, block 403, and a memory unit in which the data of force are stored, block 404.

From each measuring plate a respective flow of data is then sent to a central control unit. Therefore, in case of k measuring plates k flows of data are obtained that are sent to the central unit through a respective transmission channel, block 405. The data are, then, displayed on the display of the central control unit, block 406.

As diagrammatically shown in Fig. 12, preferably the method according to the invention provides a preliminary synchronization step of all the dedicated control unit, in particular of the microprocessors 31 of the same, block 390. The synchronization step is carried out in particular by a synchronization device 75 diagrammatically shown in Fig. 5.

In particular, the synchronization step is adapted to arrange all the measuring devices of the different plates involved in the measure in a listening status, i.e. in a status in which they are adapted to measure the forces acting on the respective support planes of the plates. A verification step follows in which the measuring devices are adapted to measure the forces acting on the support planes only if a force is detected higher than a predetermined low threshold value F*, block 391. This in order to avoid that the measuring devices can measure data not useful for the purpose of the measurement of the braking force of the vehicle. This way, it is further optimized the mangement of the measured data because it is avoided to select which data can be useful excluding the data that are not useful to this purpose. More in detail, the verification step is carried out for avoiding, for example, that the detection of the forces acting on the plane support can start owing to the accidental trampling by an operator of the measuring plate.

In Figs. 13 to 21 further exemplary embodiments of the invention are shown. More in detail, as above anticiped with reference to Fig. 8, according to another aspect of the invention, the brake test bench 100 can be mounted to an auto lift 1.

As well known, an auto lift 1 has a plane support 15 on that, in use, a vehicle 50 is arranged, for example a car. The auto lift 1 is arranged to move from a lowered configuration, at which the plane support 15 is arranged substantially at a same height of the floor 150 of the room in which it is installed and therefore the vehicle 50 can be arranged on it (Fig. 13), and a raised configuration in which the plane support 15 is arranged at a predetermined height h from the floor of the room in which the auto lift 1 is installed (Fig. 14), in order to carry out planned, or extraordinary, maintenance on the vehicle 50.

The auto lift 1 is provided with at least one safety barrier 110 arranged to pass from an access position, in which it is arranged below, or substantially at a same height, of said plane support 15, and then does not block the access of the vehicle 50 on it, when the auto lift 1 is arranged in the above described lowered configuration of Fig. 13, to a blocking position when the auto lift 1 is arranged in the raised configuration of Fig. 14, in order to prevent the vehicle 50 to withdraw beyond the position, in which the safety barrier 110 is mounted. Furthermore, a means is provided for operating arranged to cause the movement of the safety barrier 110 from the access position to the blocking position. More in detail, the actuation means is arranged to cause a translation along a substantially vertical direction of the safety barrier 110. In particular, the safety barrier remains always external to the support platform 16 of the auto lift 1.

The actuation means can provide at least one actuation arm 120 having an embracing portion 121 at which it is pivotally connected to the auto lift 1. More in detail, the actuation arm 120 is adapted to rotate about a rotation axis 101 substantially parallel to the support platform 15. The actuation arm 120 is further provided with an actuation portion 122 at which it is constrained to the safety barrier 110 and produces on it a lifting thrust for causing it to move in said blocking position, or lowering for causing it to move in the access position.

As diagrammatically shown for example in Fig. 16, the actuation arm 120 is also provided with a first application portion 123 of a first force Fl by an actuation member 30. This exerts a force Fl configured to induce a rotation of the actuation arm in a first rotation direction Rl that produces a force F _S oii on the safety barrier 110 at the actuation portion 122 that causes the movement of the safety barrier 110 from the actual access position to the blocking position when the auto lift 1 passes in the raised configuration. In the example shown in Figs. 16 to 18, the actuation member 130 is of elastic type, and precisely is a spring constrained to the actuation arm 130 at one end 131a and to a crossbar 132 at the other end 131b. In this case, the spring 130 is configured in such a way that the force Fl exerted by it thrustes the actuation arm 120 in the actuation point 123 causing its rotation about an axis 101.

The arm 110 is then provided with a second application portion 124 at which a second force F2 is applied when the auto lift 1 is arranged at a predetermined height. More in detail, the force F2 is a constraining reaction exerted by a reference surface 210, for example the floor of the room, or a base surface of the hole 200 in which the auto lift 1 is installed. The constraining reaction F2 is exerted on the second application portion 124 when the auto lift 1 is arranged at a height at which the actuation arm 120 is in contact with the above described reference surface 210, i.e. during the movement of the auto lift 1 from the raised configuration to the lowered configuration. The force F2 is opposite to the force Fl and is configured to cause a rotation of the actuation arm 120 in a second rotation direction R2 opposite to the first direction Rl . More in detail, the rotation in the second rotation direction R2 is adapted to produce a force Fab on the safety barrier 110 at the actuation portion 122 that causes it to pass from the blocking position to the access position (Fig. 18) . Until the actuation arm 120 is in contact with the reference surface 210, the force F2 is exerted on the application portion 124 and therefore the safety barrier remains in the access position. When, instead, the actuation arm 120 is not any more in contact with the reference surface 210, i.e. at a predetermined height of the auto lift 1 from the reference surface, the force Fl, which is not any more opposed by the force F2, produces its action on the arm 120 same obtaining a rotation in said rotation direction Rl that causes the passage of the barrier 110 in the blocking position.

The technical solution above described for operating the lowering of the safety barrier 110 avoids that, when the auto lift 1 is arranged in the lowered configuration, the safety barrier 110 can protrude beyond the plane support 15 blocking the outlet of the vehicle 50 from the support platform 15. At the same time the solution of the present invention ensures that the safety barrier 110 can be quickly arranged in the blocking position when needed, i.e. when the auto lift 1 is arranged in the raised configuration, in order to prevent that the vehicle 50 withdraws beyond a predetermined position. Another advantage of the present invention is the easy construction and the low cost of the safety barrier 110.

Usually an auto lift 1 has two lifting slopes and precisely a slope 5a on which, in use, the wheels of a first side of the vehicle 50 are arranged and a second slope 5b on which, in use, the wheels of the second side of the vehicle 50 same are arranged. Each slope 5a, or 5b, can be then advantageously, equipped with a respective safety barrier 10a and 10b (Fig. 15) .

In the exemplary embodiments shown in Figs. 16 to 18, at the embracing portion 122, the actuation arm 120 is adapted to slidingly engage with a slotted hole 135 obtained in the body of the safety barrier 110 that works as a guide portion for the sliding of the embracing portion 122. More in detail, the embracing portion 122 is adapted to apply said lifting/lowering action on said safety barrier at the guide portion 135.

The safety barrier 110 is provided with at least one stop member arranged to stop the rotation of the actuation arm 120 during the passage from the access position to the blocking position, when a predetermined angular position is achieved. A second stop member is, in any case, advantageously, also, provided arranged to stop the rotation of the actuation arm 120 during its passage from the blocking position to the access position when the second angular position is achieved.

If the actuation arm 120 is slidingly engaged in a slotted hole 135, at least one stop element coincides with an end 136, or 137, of the edge of the slotted hole 135. More in detail, in the case shown in Figs. 16 to 18, when the actuation portion 122 reaches the end 136 it stops the rotation of the arm 120 in the first rotation direction (Fig. 17), whereas when the actuation portion 122 reaches the opposite ends 137 of the slotted hole 135 it stops the rotation of the arm 120 in the second rotation direction (Fig. 16) .

In the exemplary embodiment of Figs. 20 and 21 a first actuation arm 120a and a second actuation arm 120b are provided symmetrically arranged. More in detail, each actuation arm 120a, 120b, has a respective embracing portion 121a, 121b, at which it is pivotally engaged to the auto lift 1. Each actuation arm 120a and 120b has, moreover, a respective actuation portion 122a and 122b at which it is constrained to the safety barrier 110 and produces on it a lifting thrust, in order to cause it to move from the access position to the blocking position, or a lowering thrust for causing it to move from the blocking position to the access position.

More in detail, in the exemplary embodiment of Figs. 20 and 21, the provided actuating element, for example the spring 130, has a first end 131a which engages with the first arm 120a and the second end 131b which engages with the second arm 120b. More precisely, the arms 120a and 120b, at the fixing points of the spring 130 have respective application portions 123a and 123b, at which the spring 130 applies the resilient force Fl . This, at the respective engagement portions 121a and 121b, causes a rotation of the arms 120a and 120b about respective rotation axes 101a and 101b, in particular in opposite directions of rotation. Analogously to what above described with reference to Figs. 16 to 18, when the auto lift 1 is arranged in the lowered configuration, the rotation of the actuation arms 120a and 120b is prevented by the reaction constraining F2 exerted at respective second application portions 124a and 124b of the actuation arms 120a and 120b. The force F2 is exerted at the application portions 124a and 124b when the auto lift 1 goes down below a height at which the actuation arms 120a and 120b are in contact with the reference surface 210.

In order to lead the rotation of the arms 120a and 120b and their sliding on the reference surface 210 the application portions 124a and 124b are provided with wheels, or small rollers 125. More in detail, the constraining reaction F2 of the reference surface 210 on the actuation arms 120a and 120b at the application portions 124a and 124b overcomes the force Fl, for example the resilient force of the spring 130, and, accordingly, causes the rotation of the actuation arms 120a and 120b same in the opposite direction with respect to the direction induced by the force Fl . This causes a lowering of the crossbar 132 and, accordingly, the arrangement of the safety barrier 110 in the access position in which it allows the vehicle 50 to access the plane support 15.

Notwithstanding with reference to Figs. 13 to 21 has a structure of brake test bench been disclosed integrated in an auto lift, an object of the present patent application is also an auto lift, as described above, on which a structure of brake tester is not installed, but provided with the features described with reference to Figs. 13 to 21.

The foregoing description of specific exemplary embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention, it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation .