GB2250825A - A testing unit for crash barriers - Google Patents

Abstract

A test unit for testing barriers has an inclinometer (34) and an associated transducer (33) together with-sensors (21 and 31) for sensing movement between a foot and a head (12) of the test unit. The improved test unit overcomes the problem of existing test units, as it may take account of angular displacement of a barrier under test. The improved test unit also calculates component forces, by utilising information from the inclinometer (34). Furthermore the test unit includes means to measure any slippage occuring between the foot (6) and the head during set up and initial extension of the boom (3). <IMAGE>

Description

A TEST UNIT.

This invention relates to a test unit which is particularly, but not exclusively, intended for testing barriers which are often present in large stadia.

A previous test unit is described and claimed in the applicant's granted UK patent 2091888B. Whilst the existing test unit is very successful it is felt that it could be improved. The existing test unit can be difficult to set up. The results of each test require meticulous recording by hand and because of the tedious nature of manual recording there is the risk of erroneous readings. No account is taken of any angular displacement of either the barrier or the test unit as the force is applied and the barrier is deflected and no measurement of any backward displacement of the test unit itself is taken when measuring any deflection. As a result readings have had to be checked in case the test unit moved. Any displacement was interpreted as movement in the barrier, which could indicate that the barrier was faulty when in fact it was not.

An aim of an embodiment of the present invention is to overcome the aforementioned problems.

According to the present invention there is provided a test unit comprising a head ,boom and an adjustable foot, means for subjecting the head to a displacement force so as to displace the head relative to the foot, means to measure the force , means to measure the displacement, and means arranged to calculate from the measured force one or more component forces acting on the barrier or item under test.

The measured force is preferably converted into an electrical signal and a microprocessor is arranged to automatically calculate the component forces.

Preferably a sensor is provided which measures the amount of slippage of the head, boom and foot with respect to a stationary point and a transducer converts this into an electrical signal. This signal may be used to provide a true value of the amount of deflection of the barrier or item under test. The foot forms part of a leg/foot assembly.

A rotary sensor may be provided which by way of a transducer, produces an electrical signal indicative of the angle of inclination of the head, boom and leg/foot assembly with respect to a nominal horizontal. The signal from the inclinometer, when used in conjunction with the signal from the slippage detector, and that indicative of the overall force, can be used to calculate the component forces acting on the barrier or item under test. The component forces of interest will usually be the force which is deflecting the barrier or item under test in a nominally horizontal direction although in some instances quite acute angles could be encountered where access to the barrier or item under test is restricted. Individual component forces may be displayed on a suitable digital display.

A hydraulic fluid may be used as a pressurising fluid to extend the head so as to apply a force to a barrier or item under test. Such an arrangement permits measurement of the pressure of the fluid by a load cell.

This value may then be used to calculate the resultant force applied to the barrier or item under test.

Preferably the load cell is situated in the head and an associated transducer converts the force into an electrical signal.

Means may be provided whereby electrical signals from the transducers may be stored after each reading.

For example this may permit several readings to be taken and an automatic averaging of them made.

Preferably the microprocessor is capable of indicating during setup of the test unit whether or not it is within programmable, optimum setting parameters and of automatically setting datum references, taking readings and performing the necessary calculations, for example to calculate the average component forces from the data derived and to store them. Such electronic storage and computing equipment may be battery powered.

The batteries may be carried within a suitable pod which may be incorporated within the boom.

An embodiment of the invention will now be described by way of example and with reference to the following figures in which: Figure 1 shows a partial sectional view of the Head Assembly along the line C-C of Figure 6; Figure 2 shows a side elevational view in partial section of a central portion of the Boom Assembly; Figure 3 shows a side elevational view of the Leg/Foot Assembly; Figure 4 shows a partial sectional view along the line A-A of Figure 1; Figure 5 shows an underplan view of the central portion of the Boom Assembly; and Figure 6 shows a sectional view along the line B-B of Figure 1 Basic Elements of the Test Unit The Test Unit comprises of three basic elements shown as figure 1 Head Assembly, figure 2 Boom Assembly and figure 3 Leg/Foot Assembly. Joining of the three elements to form the Test Unit is provided for as follows.Figure 1 shows a cylindrical female socket 1 shaped to accept the solid male cylindrical shaft 2 attached to boom 3 shown in Figure 2. Figure 2 shows a central portion of the boom 3 and an attachment 4 which is an open ended hollow tubular section, shaped to accept the male cylindrical leg 5 which supports foot 6 shown in Figure 3.

All description hereafter Presume a test unit comprising of the three basic elements as above in its assembled condition Description of Elements that Provide Basic Adjustment.

Figure 3 shows leg 5 which supports the foot 6. The foot 6 is able to swivel with respect to the leg 5 by way of pivot 7. Holes 8A, 8B, 8C are provided along the length of the leg 5. Figure 2 shows a slot 9 provided along the length of tubular attachment 4 on the end of boom 3. When assembled with leg 5 one of the holes, either 8A, 8B or 8C will coincide with the slot 9 in tubular attachment 4. A pin 10 is provided which fits through the slot 9 and resides in one of the holes 8A, 8B or 8C. There is a thread provided on the outside diameter of tubular attachment 4 onto which is screwed a threaded adjuster nut 11.The threaded nut 11, when adjusted against the pin 10 which protrudes both sides of tubular attachment 4, shown in figure 5, effects an increase in the overall length of the boom/leg assembly and when adjusted away from the pin 10 effects a decrease in the overall length of the boom/leg assembly.

This enables the test unit to be used in a variety of situations.

Description of Elements that provide means to APP1Y a Force Figure 1 shows head adaptor 12 in contact with part of a tubular barrier 13. The head adaptor 12 is depicted as being typical of the fixed type but there may be used in practice a variety of configurations both fixed and swivelling to suit many applications.

The head adaptor 12 is connected to a shaft 14 which resides within a cylinder 15, which is attached to the end of female socket 1 assembled to boom 3. In operation pressure fluid is introduced into cylinder 15 by way of a pressurizing unit (not shown) via inlet valve 16. The fluid under pressure serves to move the shaft 14 and the head adaptor 12 in the direction of arrow A, the opposite reaction to this force is applied through a load cell, the boom and leg/foot assembly to a suitable heel point, thereby exerting a force on the barrier 13 under test. To ensure hydraulic pressure is maintained after pumping has stopped an accumulator may be incorporated into the pressurizing unit (both not shown).

Description of Elements that provide means to Measure the Force Figure 1 shows a load cell 17 which is attached to the end of cylinder 15 and protrudes through to the inside of female socket 1. This abuts the solid male cylindrical shaft 2 attached to boom 3 shown in Figure 2. As the pressure is introduced the opposite reaction passes through the load cell 17 which measures the directly applied axial force.

Description of Elements that provide means to Measure Displacement Figure 1 shows a stainless steel disc 18 which is attached between shaft 14 and head adaptor 12. Mounted below cylinder 15, on brackets 19 and 20, is a linear transducer 21 and rod 22. The rod 22 is connected to the linear transducer 21 and is spring loaded against disc 18. As the shaft 14, head adaptor 12 and disc 18 move in the direction of arrow A, the rod 22 is maintained in contact with disc 18 by spring pressure and therefore moves the same amount enabling a measurement to be taken. Any rotation of shaft 14 and the head adaptor 12 has no effect on the measurement as the disc 18 rotates with shaft 14 and head adaptor 12.

Description of Elements that provide means to Measure Slippage.

Figure 2 shows the boom assembly. Mounted on the lower side of the boom 3 is a housing 23 which supports a telescopic outer leg 24. The telescopic outer leg 24 forms a tubular female socket shaped to receive a tubular male telescopic inner leg 25, this being a sliding fit with telescopic outer leg 24 thereby allowing adjustment with respect to the overall length.

There is provided a locking collar 26 whereby, once the adjustment of telescopic inner leg 25 is complete rotation of the locking collar 26, locks the telescopic inner leg 25 in place. Attached to the end of telescopic inner leg 25 is a foot 25A which pivots with respect to the telescopic inner leg 25 by way of a pivot pin 27. Figure 2 shows this leg assembly in its retracted position. When the test unit is set the telescopic outer leg 24 is lowered by way of pivot pin 28 and the telescopic inner leg 25 is extended until the foot 25A contacts the ground. The foot 25A, depicted, is typical of the type of attachment that could be used and could vary dependent on the type of surfaces encountered.

The pivot pin 28 is located into the two slotted sideplates of housing 23. The slots in the sideplates of housing 23 enable the telescopic outer leg 24 and its associated pivot pin 28 to slide in line with the axis of the boom 3. The housing 23 also contains a spring loaded pushrod 29 which abuts the radiused end of the telescopic outer leg 24. Figure 1 shows a housing 30.

Mounted inside housing 30 there is provided a linear transducer 31, and rod 32. The rod 32 is connected to the linear transducer 31 and is spring loaded against pushrod 29, shown in Figure 2. Movement of the outer telescopic leg 24, in line with the axis of boom 3, acts against the spring loaded pushrod 29 which in turn acts against rod 32 connected to linear transducer 31 thereby enabling a measurement to be taken of rearward displacement of foot 6,shown in Figure 3.

Description of Elements that provide means to Measure Ankle Figure 1 shows a housing 30. Mounted within housing 30 there is provided a rotary transducer 33 which incorporates a pendulum 34. Angular movement of the assembled test unit, alters the attitude of the rotary transducer 33 with respect to the pendulum 34, which is acted upon by gravity thereby maintaining it in a truly vertical position and therefore enabling measurement of the angle.

Basic Elements of the MicroProcessor and Operational Requirements Figure 6 shows a box 35, which maybe weatherproof, configured to accept the electronics package of the microprocessor consisting of, for example, printed circuit boards 36, display panel 37, keypad 38 and printer (not shown). The microprocessor provides the means to input, by way of the keypad 38, calibration data and parameric data, to automatically calculate and display setting and operating parameters derived from the parameric data, to automatically set all reference positions to zero as required, to automatically monitor the application of force and to sound a warning on achieving the required force, as derived from the parameric data, to automatically monitor the force applied and to sound a warning if it falls by a preset value, to automatically set a timer from the point the force required, is achieved and to then monitor the elapsed time specified for each test and to sound a warning when it is complete, to automatically store as required measurements transmitted in the form of electronic signals from all the associated transducers and load cell, to automatically calculate from those measurements, by means of preprogrammed formulae, other relational values and store them, to automatically store with the calculated values time and date of test, code number of item tested, test number, angular setting, forces applied, and elapsed times, to enable printing of all stored data as required. Other forms of data storage and retrieval may be used to enable transfer directly to a personnel computer. Power supply for all the aforementioned instruments and microprocessor is provided for by means of batteries housed in a battery pod 39 mounted adjacent to box 35.

Miscellaneous.

Figures 1 and 2 show respectively handles 40 and 41 as the means provided to carry the assembled test unit.

Description of Operation with further reference to the figures The assembled Test Unit is positioned between the barrier 13 under test and a suitable heel point which may, for example, be adjacent steps of a terracing. The overall length of the test unit is roughly adjusted by way of the threaded adjuster nut 11. The angle of the test unit will be shown on the display panel 37 and is automatically monitored during set up so that if it is outside the allowable angular variation of 0 degrees (horizontal) to minus 10 degrees the microprocessor will sound an audible intermittent signal to warn the operator. If there is no choice but to set up the test unit outside of the allowable angular variation there will be an override facility provided.

Once in the set position a code number for the barrier being tested, the parameric data, for example length of span between the vertical posts of a barrier, shall be entered by way of the keypad 38. From this and other data the microprocessor shall calculate the force required and show this on the display 37.

The manual pump is then coupled to the cylinder 15 by way of inlet valve 16 and used to pressurize the hydraulic fluid within the system, this acts upon the ram 14 displacing it in the direction of arrow A. At this point the ram 14 and head 12 is extended in the direction of arrow A until it contacts the barrier 13 thereby removing the slack within the assembly as a whole. At the moment it meets resistance and starts to register a small amount of force approximately 20 Newtons, through the load cell 17, the microprocessor shall sound a single audible signal to stop pumping.

The telescopic outer leg 24 shall be lowered at this point and the telescopic inner leg 25 adjusted until foot 25A is in contact with the ground, ensuring that it is not at an angle greater than minus 45 degrees from the horizontal.

Pressurization is then continued. At the instant the load cell 17 senses an increase in applied force the microprocessor sets the various datums by zeroing the readings of the load cell 17, linear transducer 21, linear transducer 31 and reading and storing the angular position from rotary transducer 33.

Using values obtained from the parameric data the microprocessor shall if so desired, automatically take several readings of ram displacement in direction of arrow A, displacement of foot 6 in the opposite direction of arrow A and angular change of the test unit, on achieving certain levels of applied force.

When the full test force is achieved the microprocessor shall automatically, within a period of 0-10 seconds after the full test force is achieved, take and store readings of ram displacement in direction of arrow A, displacement of foot 6 in the opposite direction of arrow A, angular change of the test unit, and the force applied, thereby recording the total deflection of the barrier under test. On completing this set of readings a single audible signal shall be sounded.

The force is then removed steadily and the head 12 and ram 14 return in the opposite direction of arrow A under the reactionary force of barrier 13. Several further readings may be taken as the barrier returns if so desired. At the instant the barrier 13, head 12 and ram 14 achieve the original setting force between 0 and approx.

20 newtons the microprocessor shall automatically take and store readings of ram displacement, foot displacement, angular change of test unit and force applied. On completing this set of readings a single audible signal shall be sounded.

This first application in the instance of barrier testing is considered to be for bedding in". A further two applications are repeated as previously described, with the exception that on achieving the full test force and the audible signal has sounded for completion of readings, the full test force is left applied for a period of 5 minutes. When this period of 5 minutes has elapsed the microprocessor shall automatically take and store a further set of displacement, angular and force readings, and on completion shall sound a continuous audible signal until such time as the microprocessor senses relief of force and or ram displacement.

The microprocessor shall, after each application of force, calculate by standard mathematical expressions the true deflection and recovery values of the barrier or item under test, taking into account any slippage of the heel point.

Recovery of the barrier or item, with respect to the deflection under test load, is subject to a minimum recovery value. If this value is not achieved the microprocessor shall automatically sound an intermittent audible signal for a period of 10 seconds and show on the display 37 "Fail" or a number that relates as a fail. If the minimum value was achieved it will show on the display 37 "Pass" or a number that relates as a pass.

All data, including deflection, heel slippage, angular, force, recovery values, elapsed time, date and code numbers will be stored after each application. If so desired a printout may be obtained at any point during or after testing. If required, data may be transferred to a personnel computer to permit further detailed analysis and to allow presentation of the data in various formats, for example, tables or graphs may be produced.

With respect to the various types of testing capable of being carried out by this test unit the micro-processor can be programmed to take readings and give audible signals of differing types as required to suit various applications The above description refers to the micro-processor being attached to or integral with the test unit for monitoring and/or analysing and/or logging data at the point of test. Further analysis is possible by transferring logged data to a Personal Computer which may be remote from the or each test unit.

There are many different possible options for transmitting data from one or several test units to a centralised micro-processor or a Personal Computer.

These options are briefly described below.

For example an operational sequence may comprise the steps of: setting up a test unit wherein a micro-processor monitors initial "set-up" angles and forces within optimum parameters. A Digital readout may then constantly provide returning data from all sensors.

An alternative embodiment involves a micro-processor monitoring and loging loads applied subsequent displacements, angles and duration of test when the test is completed, the micro-processor analyses all data and returns whether the item under test has passed or failed.

Alternatively all data stored can be printed out or "dumped" into a Personal Computer for further analyses and presentation.

A different machine has a digital readout only, and no processing ability. A micro-processor is separate and remote from it, connected by a suitable cable to one or more test units. This arrangement is only possible when several tests are carried out where the test units are in close proximity to each other.

A test unit has a digital readout and has limited processing ability to monitor initial setup parameters and enable transmission of data by telemetry to a remote micro-processor or portable Personal Computer for logging and analysis. The resultant pass or fail would then be transmitted back to the test unit and would be displayed on its readout.

Of course the remote micro-processor/Personal Computer could accept data and analyse data from several test units on the test site. Similarly means of telemetry could be either radio wave, microwave or infra red. Data could be encoded to help prevent corruption during transmission. Data could be transmitted several times to compare with previously transmitted data, to ensure non corruption.

It will be appreciated that the above is only one emodiment of the invention and that variation may be made without departing from the scope of the invention. For example the test unit may be adopted to test items other than barriers.

Claims (13)

1. A test unit comprising a head, a boom, an adjustable foot, means for subjecting the head to a displacement force so as to displace the head relative to the foot, means to measure the aforesaid force, means to measure the aforesaid displacement and means arranged to calculate from the measured force one or more component forces acting on an item under test.

2. A test unit according to claim 1 wherein the means arranged to calculate the or each component force uses information obtained from the means to measure the displacement of the head relative to the foot of the unit.

3. A test unit according to claim 1 or claim 2 wherein a sensor is provided for measuring the amount of slippage of the head of the unit with respect to a stationary point.

4. A test unit according to claim 1 or 2 wherein a sensor is provided for measuring the amount of slippage of the boom with respect to a stationary point.

5. A test unit according to claim 1 or claim 2 wherein a sensor is provided for measuring the amount of slippage of the foot with respect to a stationary point.

6. A test unit according to any of claims 3, 4 or 5 wherein a transducer associated with the sensor outputs an electrical signal.

7. A test unit according to any preceding claim wherein a rotary sensor and an associated transducer is provided for producing an electrical signal indicative of the angle of inclination of the boom test with respect to a nominal horizontal.

8. A test unit according to any preceding claim wherein an hydraulic fluid is used as a pressurising fluid to displace the head of the test unit relative to the foot.

9. A test unit according to claim 8 wherein a load cell is provided for measuring the pressure of the fluid.

10. A test unit according to any preceding claim wherein transducer readings may be stored in a memory.

11. A test unit according to any of claims 1 to 10 wherein readings may be transmitted to a remote monitoring station for storage and/or analysis.

12. A plurality of test units arranged to transmit data to a remote monitoring station for storage and/or analysis.

13. A test unit substantially as herein described with reference to the figures.