GB2595977A - Tyre tread checking device - Google Patents

Abstract

A tyre tread depth checking device for measuring the depth of tread across a tyre on a wheel of a vehicle. The device having a measuring head including a profile gauge, a holding mechanism with movement means to push the gauge against the tyre to create a contoured profile on the gauge by contact with the tyre tread, a handling support to locate the gauge at the tyre while allowing a user to remain standing in use and recording means to record the measured depth of tread as shown by the contoured profile on the gauge. Embodiments are described in which the movement means is by a wheeled sub-frame and by air pressure from a bladder operated by a user. The recording means is by a sheet on which a permanent record of the contoured profile can be made as evidence of the tread depth.

Description

TYRE TREAD CHECKING DEVICE

The present relates to tyre tread depth measurements and in particular to a tyre checking device to mechanically determine the tread depth across a tyre on a 5 motor vehicle.

UK Law requires motor car tyres to have a minimum depth of tread of 1.6mm which must forin a contiguous band around 75% of the central area of the tyre. Many tyre manufacturers mould tread indication bars on their tyres at 1.6mm 10 allowing for ease of checking the tyre wear.

Steering problems and poor wheel alignment can cause front tyres to "leather" or more fitting excessively wear down on one side. This defect leads to rapid wearing of the tyres and often down to the underlying structural layers of the tyre. 15 This dangerous and illegal wearing is readily observed.

When Traffic Policemen check a cars tyres they are obliged to bend down or kneel to carry out the inspection. During heavy rain fall one can well imagine why many Police Officers may be reluctant to kneel down on wet roads to inspect tyres 20 resulting in tyre checks possibly being omitted on such days.

Whether tyre inspections are carried out by eye, a small tread measuring gauge or even the edge of a coin there is no physical record made of that inspection thus solely relying upon the Policemans verbal evidence to support the fact that a 25 criminal offence had been committed by the errant motorist.

It is the idea of this invention to provide a simple, safe and reliant means of physically checking tyre treads without the inspector either bending or kneeling down, notwithstanding the fact that the device will also be used to create a permanent record of the tyres condition at the time of the test. This record will be of significant use in a Court of law should the offending motorist decide to argue that his tyre or tyres were not in fact illegal at the time.

According to a first aspect of the present invention there is provided a tyre tread 35 depth checking device comprising: a measuring head including a profile gauge; a holding mechanism with movement means to push the gauge against a tyre to create a contoured profile on the gauge by contact with the tyre tread; a handling support to locate the gauge at the tyre while allowing a user to remain standing; and recording means to record the measured depth of tread as shown by the contoured profile On die gauge.

In this way, a user does not need to kneel or bend down to access the tyre tread. The device is entirely mechanical so that it is tamper-proof and always operational. Current measurement gauges are hand-held and electronic, making a user kneel or bend to access a tyre on a motor vehicle and requires a supply of spare batteries. The measurement is calculated electronically and displayed providing an argument for incorrect measurements by miscalibration and/or loss of power.

The motor vehicle may be a motor car, van, motorbike, lorry or other motorised transport which has tyres on wheels.

Preferably, the profile gauge comprises a plurality adjacently arranged fingers, each finger being free to move relative to the other fingers when a first end thereof contacts a surface. In this way, when the fingers are pushed against a tyre, those lying between treads will be pushed back while the remaining fingers fall into the treads an amount equal to the depth of the respective tread. In this way, as the fingers can be dimensioned so that more than one fits in a tread, the depth of each tread is more accurately determined than for the prior art devices which rely on a single being inserted into a tread. Preferably also, the profile gauge has a length greater than a tyre width upon which a measurement is intended to be made. In this way, depth measurements are made for all treads regardless of the tread profile of the tyre, in a single measurement over the entire width of the tyre.

Preferably, the movement means is a wheeled subframe. With the measuring head mounted on the wheeled subframe and the handling support attached thereto, the device can be pushed against a tyre while the user stands. Advantageously, the profile gauge and the handling support are on opposite sides of the holding mechanism, so that in use the user, moves the device forwards and backwards. This means that the user can safely make measurements at a stationary vehicle by standing in front and/or behind the vehicle and does not have to stand in the pathway of other moving vehicles.

Alternatively, the movement means comprises a sealed chamber over second ends of the fingers of the profile gauge, the chamber connecting to an inflatable bladder In use, the inflatable bladder is squeezed by the user, providing increased pressure in the chamber sufficient to move the fingers forwards out of the chamber. A line between the chamber and the bladder may be provided so that the bladder is located at the top of the handling support.

Preferably, the profile gauge includes a clamp, the clamp being moveable against the fingers to selectively hold the fingers in position. In this way, the fingers can be safely stored without their movement and once a measurement is made by pushing the fingers against a tyre, the clamp is moved to hold the fingers in the contoured position. In this way, the contoured position is maintained so that it can be recorded.

Preferably, the handling support is a multi-part rod. In this way, the device may include a carrying case and all the parts can fit therein while when in use, the handling support is of sufficient length for a user to place the measuring head on the ground and stand while holding the handling support. The multi-parts may be twist fit, screw-fit or the like joints to provide simple and rapid assembly of the device. Preferably, the handling support includes engagement means to affix to the holding mechanism. In this way, the handling support is used to steer the device to and against the tyre.

Preferably, the recording means is a sheet which is located against the contoured shape of the fingers one the measurement has been made. A line can then be scribed to make a permanent record of the tyres wear pattern on the sheet. The recording means may include a shoe configured to attach to the measuring head, the shoe supporting the sheet for the line to contoured shape to be marked. The sheet may include space for further details of the tyre, vehicle, owner etc. to be recorded.

According to a second aspect of the present invention there is provided a method of measuring tyre tread depth across a tyre, comprising the steps: (a) providing a tyre tread depth checking device according to the first aspect; :3 b) locating the support on the measuring head; (c) while in a standing position, holding an end of the handling support and positioning the profile gauge across a tyre on a motor vehicle; (d) operating the movement means to push the gauge against a tyre and creating a contoured profile on the gauge by contact with the tyre tread; and (e) taking a record of the measured depth of tread as shown by the contoured profile on the gauge.

0 In the description that follows, the drawings are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce the desired results.

Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes.

All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein including (without limitations) components of the apparatus are 30 understood to include plural forms thereof Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a plan view of a tyre tread depth checking device according to an embodiment of the present invention; Figure 2 is a side view of the tyre tread depth checking device of Figure 1; Figure 3 is an illustrative evidence sheet showing a contoured profile providing a recording of the measured depth of tread from a tyre tread depth checking device 5 according to an embodiment of the present invention; and Figure 4 is a top view of a tyre tread depth checking device according to another embodiment of the present invention.

Reference is initially made to Figures 1 to 3, of the drawings which illustrate a tyre tread depth checking device, generally indicated by reference numeral 10, having a measuring head 12 including a profile gauge 14; a holding mechanism 16 with movement means 18 to push the gauge 14 against a tyre 20 to create a contoured profile 22 on the gauge 14 by contact with the tyre tread 24; a handling support 26 to locate the gauge 14 at the tyre 20 while allowing a user 28 to remain standing; and recording means 30 to record the measured depth of tread 32 as shown by the contoured profile 22 on the gauge, according to an embodiment of the present invention.

In an embodiment, the tyre tread checking device 10 comprises of: a measuring head 12 consisting of a non-high tech profile gauge 14. The profile gauge 14 will take and record the depth 32 of the individual tyres tread 24 as shown by the profile gauges 14 multiple individual fingers 34; a holding or clamping mechanism 16 with which to hold the profile gauges fingers 34 in place post they have taken a reading; a four wheeled subfi-ame 36 or supporting mechanism to hold and support the profile gauge 14 against the suspect tyre 20 thus allowing the tester 28 to remain standing throughout the actual testing phase; a removable shoe 38 (see Figure 3) which clips against the profile gauge 14 once the tread depths 32 has been recorded. Within this shoe 38 an evidence sheet 40 is placed whereupon the testing party 28 will scribe a line 42 across the testing fingers 34 said line 42 making a permanent record of the tyres wear pattern 44; a two piece rod or tube 46 which, when clipped together and attached to the subframe 36, allows the tester 28 to push and pull the testing apparatus 10 first against the tyre 20 then pulled away from said tyre 20 once the readings have been taken. :35

Now considering the individual components of the tyre checking device 10 and use.

The Measuring Head 12: This consists of a profile gauge 14 similar to those used by carpenters and shop fitters to duplicate/copy shapes or features which said artisans wish to replicate or transfer onto a second piece of timber or whatever object. The profile gauge 14 has a stacked array of fingers 34 which are free to move longitudinally with respect to each other. There may be between 100 and 200 fingers 34 on the gauge 14, but the total number is optional and dependent on the width of the gauge 14, which should be at least as wide as the tyre 20, and the resolution required i.e. a number of fingers 34 should fit within each tread 24.

While the fingers 34 may be plastic they are preferably metal such as steel. The integral fingers 34 of the profile gauge 14 will show a reverse image of the tyres tread pattern 44. Once the test is completed and the device withdrawn a holding shoe 38 is firmly clipped onto the profile gauges front face 48 whereupon a critical line 42 can be drawn across a pre-printed graph and evidence sheet 40. A fine writing instrument is used to draw the line 42 across the fingers 34 of the profile gauge 14 over the contoured profile 22. Comparing the drawn line 42 against the evidence graph immediately allows the tester to see if the tyres tread 24 is within its legal limits.

Four wheeled Subframe or supporting mechanism 36. This wheeled subframe or supporting mechanism 36 is a holding mechanism 16 which provides movement means 18. The subframe 36 supports the profile gauge 14 throughout its use thus allowing the testing officer 28 to stand as he/she carries out the actual tyre 20 testing. In regards to the safety issue regarding 'standing' in front of or to the rear of the car or other motor vehicle, tyre testers have no need to move onto any juxtaposition roads while carrying out these tests. The front wheels will be enlarged in order to place the device 10 support platform 54 at a better angle. The tyre 20 under test needs to be read at 90 degrees. As it is the device 10 engages the tyre 20 at a poor angle causing the measuring finger 34 to engage the tyre at a much greater angle than 90 degrees. This disables the fingers 34 from taking a clean reading. The supporting mechanism includes a handle 68 to provide easy lifting of the device 10.

Document/Evidence Holding Shoe 38: The shoe 38 provides the recording means 35 30. This holding element or shoe 38 will firmly and accurately clip onto the front face 48 of the profile gauge 14 once the measuring pins or fingers 34 have been clamped in position. Located within this holder/shoe 38 will be a detailed form included in which is a visual measurement checker. Once the fingers 34 of the measuring head or profile gauge 14 have automatically extended owed to them being pushed against the tyre 20 the fingers or pins 34 must be securely clamped by the use of two large headed nuts 50a,b once the device 10 is recovered from under the vehicle. This clamping must be executed immediately upon the "fully functioned" testing apparatus 10 being withdrawn from the vehicles underside.

The Pushing Pulling and Steering Mechanism: This may be considered as the handling support 26. This is accomplished using two narrow tubes or poles 52a,b that lock into each other before the now 'single rod' 46 is secured onto the main body or subframe 36. The idea of using two tubes 52a,b rather than one single tube is for ease of storage and transportation in Police vehicles. The length of a joined tube should be in the order of 1.1 to 1.3 metres. A diameter of circa 35 to 40 mm is desirable. The joining mechanism of the individual tubes 52a,b is accomplished by a push fit and a 90 degree twist. The tubes are fitted with two opposing pins which lock into each others matching slots. The assembled tube is then locked into the supporting mechanism or sub frame 36. it will be appreciated that other connection mechanisms may be used.

Measurement and Recording Forms 40: This forms the recording means 30. This is the record/evidence sheet 40 where all the taken measurements are logged directly from the actual measuring head 12. This form or logging sheet is held in the bespoke holding shoe 38 which ensures the measuring head 12 or profile gauge 14 aligns with and matches the same If upon proof being shown that the tested tyre 20 is within the legal limits there is no need to continue with that particular test thus allowing the testing of the next suspect tyre 20.

It will be noted that in regards to the design of the actual evidence/recording form 40 this will be subject to Police requirements. it will be appreciated that the measuring graph itself must be of a standard design however, the other information held on the form should be at least; [i] The drivers name and address, [ii] The vehicles registration number, [iii] The locus and time where the tyre/s test was executed and [iv] Contain a space for the drivers signature. The inventor envisages that these forms should be self duplicating insofar as the top copy, once signed by the errant driver, are given to the driver and underlying copies kept as Police evidence should the driver seek to challenge the offence in Court. Given the fact that the driver has signed the appropriate form post witnessing the live test of his tyre/s there should be no exculpatory material available to him As the apparatus 10 is basically a measuring device and its use uncomplicated it should not require Home Office approval. However, the recording forms may.

The Modus Operandi. When wishing to test a vehicles tyres 20 the Police Officer 28 first removes the apparatus 10 from its bespoke carrying case (not shown). Joining the push/pull steering rod 52a,b by their securing mechanisms he/she then attaches the rod 46 to the four wheeled subframe 36 and secures said rod 46 to it.

Placing the apparatus 10 on the road in line with the wheel fitted with the suspect tyre 20 the officer 28 slackens the two overhead clamping nuts 50a,b, bearing in mind that when not in use the fingers 34 of the profile gauge 14 should always be clamped by said nuts 50a,b.

Ensuring that the fingers 34 of the profile gauge 14 are free and level the operator 28 must also ensure that the fingers 34 are in their fully retracted position. It is also advisable here to ensure that all the measuring fingers 34 are free to move independently.

Checking the alignment with the targeted wheel the operator 28 firmly pushes the device 10 against the tyre 20 by the use of the push/pull steering rod 46. It is imperative here that the device 10 is not moved from side to side but rather it is firmly advanced towards the targeted wheel and tyre 20. Should for some reason the device 10 be misaligned or moved from right to left (or visa versa) while pushing the same against the suspect tyre 20 the device must be withdrawn and the fingers 34 of the profile gauge 14 reset into the rearmost position. Basically should the apparatus 10 not be correctly aligned it will automatically take a spurious reading.

On pushing the profile gauge 14 against the tyre 20, the fingers 34 will move and forin a contoured profile 22 matching the tyre tread 24 across the entire width of the tyre 20. Using the nuts 50a,b the fingers 34 are clamped in position to prevent any movement thereof The shoe 38 with the evidence sheet 40 is clipped to the front face 48 of the profile gauge 14 and the contoured profile 22 matched to a graph on the sheet 40. The graph indicates the depth of tread 32. Were the depth of tread 32 from the contoured profile 22 is insufficient to match the required depth, the tyre 20 has failed.

If it is subsequently proven that the depth of the tested tyres tread is illegal the testing officer 28 will use a bespoke pen or writing instrument to mark the depth of the tread onto the graph paper, as illustrated in Figure 3. At this time the tester will then append the test paper with the drivers details, his vehicles registration number and all the requisite details.

The errant driver having signed the details and evidence form 40 will be provided with a copy document after which a relevant charge will be proffered against him to for using a vehicle with an illegal tyre or possibly tyres.

After use and possible contamination with rain and road dust or the like, it should be washed down with hot soapy water. Once dried a liberal spray with WD40 will maintain the device and keep it fiinctional. As there is no electronics used within the device soapy water and WD40 will not affect its ability to operate. On the subject of being a non-complicated apparatus per se one should remember that any damage occasioned to it will be easily rectified by the mechanics working in Police workshops. Having stated that the apparatus 10 is not a toy and will endure rough handling.

Reference is now made to Figure 4 of the drawings which illustrates a tyre tread depth checking device, generally indicated by reference numeral 110, according to further embodiment of the present invention. Like parts to those of Figures 1 and 2 have been given the same reference numeral with the addition of 100 to aid clarity. In this embodiment, the subframe 136 does not include any wheels and the movement means 118 now constitutes an inflatable bladder 56 using fluid or air pressure to move the fingers 134.

Now considering the individual components of the tyre checking device 110 and 30 use.

The Measuring Head 112: This will be a modified 10 inch Saker TM profile gauge 114 or similar. Once the gauge 114 has been held against the tyre and activated by air pressure the indicating 'fingers' 134 will show a reverse image of the tread pattern. When completed the reading head (or profile gauge 134) is unclipped from its holder and held against a pre-printed graph styled form 40. A fine writing instrument is then drawn across the measuring heads fingers 134 thus transmitting their shape onto the bespoke checking/evidence form 40. Comparing the drawn line against the graph will immediately allow the tyre inspector 28 to see whether or not the tyre treads 24 are within legal limits If the tyre treads 24 prove to be illegal the evidence sheet 40 is unclipped from the file and maintained for 5 evidence. Obviously the drivers name, details and car registration number will be appended on the form for prosecution purposes. Upon the measuring gauge 114 being placed against the evidence form it will become apparent if the tyre tread is legal or not. Obviously if the reading shows the tread depth 32 to be within legal limits there will obviously be no need to fill in the evidence form per se. In 10 the event of a fatal accident it may be good practise to record the details of all the damaged cars tyres.

Holding Mechanism 116: This holder is a captivating device fitted with an integral inflatable mechanism 58 with which to push the measuring head 112 against the tyre 20 under test. A sealed chamber 60 including a piston 66 is arranged around the ends of the fingers 134 connected by an airline 62 to a bladder 56. The inflation of the 'pushing mechanism' 58 i.e. movement means 118 will be by means of a small rubber bladder 56 which will be physically squeezed by the tyre inspector 28. Once the fingers 134 of the measuring head 112 have extended the air pressure is no longer required as the measuring head 112 itself will hold the measuring fingers in position. The rubber bladder inflator 56 will be similar to the 'inflators' found in a Doctors bag and used when carrying out a Blood Pressure test on a house bound patient.

The Carrying Mechanism or Handling Support 126: This is a telescopic or foldable pole or shaft 160 approximately 1.10 metres long when fully extended. When in its collapsed or folded state the pole or shaft 146 should be no longer 60 cm. Any longer would make it more difficult to store in a police car or SUV. At the business end per se the holding mechanism 116 is located for the purpose of firmly holding and clipping the measuring head 112 in position. Incorporated within the carrying mechanism 126 is the small bladder inflator 56 with its inflating airlines 62 stowed within it Also, at the business end there will be a full width and appropriately angled stay or support 64 at ground level. This support or stay 60 will be required to firmly hold the measuring head 112 against the tyre when the requisite air pressure is applied. Should a stay 64 not be employed the measuring head 112 would be rendered useless as the head 112 would be simply pushed back and away from the tyre 20 when the requisite air pressure was applied to the head 112.

Recording Booklet 30: This will be the book or record where all measurements 5 are logged directly from the measuring head. The booklet or logging book must be held in a bespoke frame and manufactured in such a manner so as to ensure that the measuring head 112 will match the same and be firmly held in line with the printed graph thus allowing an accurate line to be drawn on the graph by a bespoke writing implement across the contoured profile 22 from the fingers 134. 10 Once drawn on the underlying graph the operator will immediately see if the tested tyre 20 has a legal tread pattern 44.

The Modus Operandi. When a Traffic Policeman 28 wishes to test a vehicles tyres 20 he removes the carrying mechanism 126 from its stowage space and extends 15 the same. He then attaches the measuring head 112 onto the carrying pole 146 and clips the same in place.

The officer 28 then connects the airline into the pushing assembly or piston 58. Before offering the device 110 to the tyre 20 to be tested the user 28 must unclip the stay 64 which ensures the measuring head 112 will (a) maintain the head 112 at the appropriate angle against the tyre 20 and (b) prevent the measuring head 112 from being pushed away from the tyre 20 when air pressure is fed to the activating piston. The stay 64 will obviously lay on the road causing it to function like an anchor.

The tester 28 then inflates the piston 66 by means of the bladder 56 which is stored inside the carrying mechanism 126. This inflation should take less than one minute including the automatic readings taken by the fingers 134 extending from the measuring head 112. The tester 28 then removes the equipment 110 from under the vehicle, releases the air from the actuating piston 66 and carefully unclips the measuring head 112 from its' carrying mechanism 126. Taking the measuring head 112 to the vehicle the tester 28 then clips the head 112 into framework holding the graph paper 40. Once done so the tester 28 will immediately see if the depth of the tyre treads 32 are legal or not. Obviously if it is subsequently proven that the depth of the tread 32 is illegal the tester 28 will use the bespoke pen to mark the depth of the tread 32 onto the graph paper 40. At this time the tester 28 will then append the test paper 40 with the drivers details and his vehicles registration number. A charge can then be made against the driver for having an illegal tyre 20 on his vehicle.

It would be beneficial that the graph paper 40 has a duplicating ability in order 5 that errant drivers can be supplied with a copy of the evidence that has proven he has committed an illegal act.

Claims (11)

1. CLAIMS1. A tyre tread depth checking device comprising: a measuring head including a profile gauge; a holding mechanism with movement means to push the gauge against a tyre to create a contoured profile on the gauge by contact with the tyre tread; a handling support to locate the gauge at the tyre while allowing a user to remain standing; and recording means to record the measured depth of tread as shown by the contoured profile on the gauge.
2. 2. A tyre tread depth checking device according to claim 1 wherein the profile gauge comprises a plurality adjacently arranged fingers, each finger being free to move relative to the other fingers when a first end thereof contacts a surface.
3. 3. A tyre tread depth checking device according to claim 1 or claim 2 wherein the profile gauge has a length greater than a tyre width upon which a measurement is intended to be made.
4. A tyre tread depth checking device according to any preceding claim wherein the movement means is a wheeled subframe and the handling support attached thereto.
5. 5. A tyre tread depth checking device according to any one of claims 1 to 3 wherein the movement means comprises a sealed chamber over second ends of the fingers of the profile gauge, the chamber connecting to an inflatable bladder.
6. 6. A tyre tread depth checking device according to any preceding claim wherein the profile gauge and the handling support are on opposite sides of the holding mechanism.
7. 7. A tyre tread depth checking device according to any one of claims 2 to 6 wherein the profile gauge includes a clamp, the clamp being moveable against the fingers to selectively hold the fingers in position. 1:3
8. 8. A tyre tread depth checking device according to any preceding claim wherein the handling support is a multi-part rod including engagement means to affix to the holding mechanism.
9. 9. A tyre tread depth checking device according to any preceding claim wherein the recording means is a sheet which is located against the contoured shape of the fingers once the measurement has been made.
10. 10. A tyre tread depth checking device according to claim 9 wherein the recording means includes a shoe configured to attach to the measuring head, the shoe supporting the sheet for the line of the contoured profile to be marked.
11. 11. A method of measuring tyre tread depth across a tyre, comprising the steps: (a) providing a tyre tread depth checking device according to any one of claims 1 to 10, (b) locating the handling support on the measuring head, (c) while in a standing position, holding an end of the handling support and positioning the profile gauge across a tyre on a motor vehicle; (d) operating the movement means to push the profiled gauge against a tyre and creating a contoured profile on the profile gauge by contact with the tyre tread; and (e) taking a record of the measured depth of tread as shown by the contoured profile on the gauge.