GB2455564A - Apparatus for measuring the friction of a surface. - Google Patents
Apparatus for measuring the friction of a surface. Download PDFInfo
- Publication number
- GB2455564A GB2455564A GB0724401A GB0724401A GB2455564A GB 2455564 A GB2455564 A GB 2455564A GB 0724401 A GB0724401 A GB 0724401A GB 0724401 A GB0724401 A GB 0724401A GB 2455564 A GB2455564 A GB 2455564A
- Authority
- GB
- United Kingdom
- Prior art keywords
- weighted member
- force
- move
- assembly
- test
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000012360 testing method Methods 0.000 claims abstract description 76
- 230000007246 mechanism Effects 0.000 abstract description 17
- 239000000463 material Substances 0.000 description 12
- 210000002683 foot Anatomy 0.000 description 6
- 230000008859 change Effects 0.000 description 4
- 239000002783 friction material Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 230000009471 action Effects 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 2
- 210000000544 articulatio talocruralis Anatomy 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 231100001261 hazardous Toxicity 0.000 description 2
- 230000036541 health Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/02—Measuring coefficient of friction between materials
Landscapes
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
Abstract
An apparatus 2 for measuring the grip of a subject surface, has a weighted member 4, means 8,10 e.g. a pulling mechanism and chord, for applying a force to move the weighted member 4 with respect to the subject surface, and means 12 e.g. a spring balance, for measuring the force applied to move the weighted member 4. The apparatus 2 has a surface assembly 6 having a test surface for contacting the subject surface and onto which weights (18, fig 3) of the weighted member 4 are applied. The surface assembly 6 has means to allow the test surface to be interchanged, and in another invention, the angle of orientation of the weighted member 4 with respect to the surface assembly 6 can be adjusted.
Description
1 2455564
APPARATUS FOR MEASURING THE FRICTION OF A SURFACE AND
METHOD OF OPERATING THE SAME
The present invention relates to an apparatus for the measurement/comparison of the friction of a variety of different surfaces.
When a surface becomes wet, or contaminated with other substances, the friction of the surface, that is its resistance to slip, will change. This often leads to slips and falls by persons walking or running on the surface. This can be especially hazardous in the work place when working with heavy machinery and the like.
Apparatus for measuring the coefficient of friction of a surface and the surface *:* 15 profile are well known in the art. Most are complex and very expensive, making them inaccessible to many smaller companies. * *. * S.
*....: * Examples of known apparatus and devices are disclosed in DE 4201124; DE 199221760; CA 1273221; DE 202006025416; DE 10028708; CA 2527082; *** : 20 WO 0229376; US 6430520; JP 20042714119; CN 2645077Y; and JP * S 2005337918.
It has also been found that obtaining a value for the coefficient of friction for various surfaces is not generally helpful as most people have no idea what friction value is necessary to achieve a non slip condition under variable states of contamination. Rather, those responsible for slip safety require a means of direct comparison of how a specific material, such as a shoe sole or tyre tread, will react with a given surface and to be able to evaluate directly the improvement obtained by a range of custom safety surface treatments.
Health a safety laws increasingly require employers to provide the best equipment possible to prevent staff from slipping and injuring themselves.
This is increasingly important where employees are required to carry out work in areas where floors inevitably become wet or impregnated with other substances, which may make people using them more prone to slip and fall.
Accordingly, there is a need for a simple to use and inexpensive device that will allow a user to evaluate the best combination of materials, such as footwear or tyre tread, and surface covering available in order to prevent slippage.
According to a first aspect of the present invention, there is provided an apparatus for measuring the grip of a subject surface, comprising a weighted member, means for applying a force to move the weighted member with :* i respect to the subject surface, and means for measuring the force applied to *, * move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto * which the weight of the weighted member is applied, wherein the surface assembly comprises means to allow the test surface to be interchanged. * 20
is....
* The function of the apparatus is to compare the slip resistance of surfaces, in particular those surfaces used by both vehicular and pedestrian traffic. The apparatus allows a user to rapidly compare a range of materials when in contact with the subject surface and to determine their relative resistances to slippage when moved along the subject surface. The apparatus is particularly advantageous in that the user is not required to determine or calculate such factors as coefficients of friction in order to may the comparison, but rather obtains a direct comparison of the slip resistance of the various test materials and/or the subject surface under different conditions.
In use, a force is applied to move the apparatus along the subject surface with the test surface contacting the subject surface and providing a resistance to such movement. The device incorporates means for measunng a force, such as a measuring gauge, with the facility to read the forces applied to the apparatus, including the applied force after the slippage has occurred. In use, the slip resistance is measured using a variety of test pieces, for example actual footwear or the soles of footwear, to enable a comparison to be made of the suitability of such footwear in a real life situation. Comparison can also be made of existing surfaces under different conditions, for example wet or dry, clean or contaminated. In such a case, the apparatus may be provided with a standard test surface on the surface assembly to contact the subject surface. The standard test surface will typically have known properties. The response of the subject surface under the differing conditions may then be tested using the standard test surface. * S
The apparatus comprises a weighted member, which provides a load acting through the test surface and bearing on the subject surface. Provision may be ****** * made to vary the load on the test surface, and/or also the distribution of the load, to simulate real foot movement. In this way, the apparatus allows the 20 risk of slippage to be determined under different load conditions, for example at various stages in the stride of a person walking or running.
The apparatus also enables the comparison of various non-slip surfaces used to minimise slip risk, for example coatings or coverings that may be applied to a floor or walkway. In use, such non-slip surfaces may be assessed using one or a variety of test surfaces affixed to the apparatus itself.
As noted above, the apparatus further comprises means for measuring the force applied to move the apparatus along the subject surface. The means for measuring the applied force may be fixed. More preferably, the said means is adjustable in aspect, in order to keep the measuring plane of the means parallel to the subject surface for consistent readings. In this way, the apparatus is also able to compare surfaces in sloping situations, that is movement uphill, downhill and/or across the slope of the subject surface.
The weighted member may be of any suitable weight to allow the required comparison of surface properties to be obtained. In one embodiment, the weighted member is of sufficient weight that it simulates the weight of a person. This may allow a more accurate indication of real-life risks of slippage to be obtained. However, the maximum applied weight may be limited by other components of the apparatus, for example the means for measuring the applied force. In this respect, spring balances can prove difficult to operate when coupled to weights approaching those of a typical person. In such a case, a maximum weight of 50kg has been found to be suitable for carrying outthetests. *... * * ***
The weighted member may be of a fixed weight. Preferably, the weight of the weighted member is adjustable, so as to allow a user to test the grip of a surface for a specific individual or set of circumstances. This may be :. achieved, for example, by adding or removing weights onto the weighted *:..:: 20 member, in accordance with either a specific weight of an individual or an average weight to give a more general figure.
The test surface may be the surface of any material that it is desired to test for slippage on the subject surface. In one embodiment, the test surface is in the form of a sole of a shoe. This allows a user to test and compare specific shoes soles so as to allow selection of the shoe sole most suited to the environment. In one arrangement, the surface assembly comprises a means for supporting a complete shoe, such as a last, whereby the test may be carried out using an entire shoe, rather than just the sole portion.
An alternative embodiment of the apparatus allows portions of tyres to be affixed to the surface assembly, to allow the performance of tyre tread patterns and compositions to be examined.
The test surface may be flat or may be contoured, such as is the case of the sole of a shoe.
The means for measuring the force applied to move the weighted member may be any suitable means. One convenient means comprises a spring balance. The spring balance may be of any design commonly known in the art and such balances are available commercially.
The spring balance is preferably contained within,, guide block. The guide block ensures the spring balance is maintained In the correct position with respect to the weighted member and the surface assembly. The guide block preferably further comprises a support sleeve. The support sleeve is S preferably manufactured from a low friction material, such as PTFE. The S..... . * * support sleeve allows the spnng balance to move freely within the support :. sleeve.
S.....
* The means for applying force to move the weighted member may act through any part of the apparatus. The means is preferably adapted to pull the apparatus. The means preferably acts to move the weighted member by applying a force in a lateral direction that is substantially parallel to the subject surface. The means for applying the force should be arranged to provide a repeatable application of force in a manner that is consistent from test to test.
The means for applying a force to the weighted member is preferably automated, again to ensure that an equal force is applied each time the apparatus is used. Alternatively, the means for applying the force may be manually operated. In its simplest form, the means for applying the force comprises a handle or the like which may be gripped by the user to apply a force through the measuring means, such as a spring balance, directly to the apparatus.
In this respect, one preferred arrangement is to have the measuring means, such as a spring balance, mounted to a plate. One end of the measuring means is connected either directly or indirectly to the weighted member, for example by a chord. The second end of the measuring means is provided with a chord or the like, such that a force may be applied to the weighted member through the measuring means. One particularly preferred arrangement is to have the measuring means mounted on a plate sufficiently large for the user to stand with one foot either side of the measuring means and apply the force to the weighted member by pulling upwards on a chord or the like. The underside of the plate is preferably coated with a high friction ". 15 material or formed to provided a high friction with the subject surface, in order to prevent the plate from moving during the test. The plate may be flexible, for example by being hinged, in order to accommodate a rough or irregular subject surface. p
As noted, the apparatus allows subject surfaces to be tested that are p.....
* S horizontal or inclined. When testing the performance of a test surface on an inclined subject surface, a particular issue arises when the test surface is the.
sole of a shoe. In general, a person walking or running up, down or across a slope will keep their body substantially vertical, with the angle of the slope being accommodated by the joints in the legs, in particular the ankle joints. In order to more accurately simulate the movement of a person on an inclined subject surface, the apparatus preferably allows the weighted member to be moved relative to the surface assembly, such that the weight may be applied at an angle to the surface assembly and the test surface. In this way, the apparatus may be oriented on an inclined subject surface such that the weight of the weighted member is acting substantially vertically.
Accordingly, in a further aspect, the present invention provides an apparatus for determining the grip properties of a test surface in contact with a subject surface, the apparatus comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable.
Any suitable means may be used to change the angle of orientation of the weighted member to the surface assembly. One preferred arrangement is to have the weighted member pivotably mounted with respect to the surface ". 15 assembly. e.
In order to better simulate a person moving across an inclined surface, the weighted member is preferably mounted so as to be rotatable with respect to the surface assembly. In this way, the weighted member may be both rotated and tilted relative to the surface assembly in order to achieve a vertical action * of the weight.
The apparatus preferably comprises means for locking the weighted member in relation to the surface assembly.
Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which: Figure 1 shows a perspective representation of the apparatus from the side; Figure 2 is a representation of a more detailed view of the means for applying a force to the apparatus of Figure 1 from above; and Figure 3 is a representation of a more detailed view of the weighted member of the apparatus of Figure 1.
The embodiments of the present invention will be described in relation to shoe soles and tyres. However, it is to be understood that the apparatus may be applied to many other situations where the grip of other surfaces may need to be measured and compared.
Referring to Figure 1, there is shown a preferred embodiment of the apparatus, generally indicated as 2, as viewed from the side. The apparatus :..::: comprises a weighted member 4 in the form of a generally flat plate, to which *...
weights can be applied and removed as desired.
Attached to the underside of weighted member 4 is a surface assembly 6, :. again in the form of a generally flat plate. A shoe sole, or part of a tyre or the * like can be attached to the underside of the surface assembly 6 so as to S....
* 20 enable the user to evaluate the surface to be tested. The surface assembly 6 is formed to allow the surface to be tested to be readily mounted to the apparatus and removed, to allow a plurality of tests to be conducted in quick succession. The shoe sole or tyre to be tested is releasably secured to the underside to the surface assembly 6 by suitable means, for example screws, bolts, clips or the like.
A pulling mechanism 8 is attached to one end of the surface assembly 6, by means of a cord 10. The pulling mechanism 8 comprises a spring balance 12 for measuring the force required to move the weighted member 4 and the surface assembly 6. In use, the weighted member 4 and the surface assembly 6 are moved by the pulling mechanism 8 using the cord 10. The spring balance 12 records the force required to move the combined weighted member 4 and surface assembly 6 for the surface to be tested.
Referring to Figure 2, there is shown a detailed view of the pulling mechanism, generally indicated as 10. The pulling mechanism 10 is mounted on a plate 14. The plate 14 is coated with a high friction material on its underside for contact with the subject surface and to prevent movement of the plate 14 during the test.
As noted, the pulling mechanism 10 comprises a spring balance 12. The pulling mechanism 10 further comprises a drive assembly 16, by which a force is applied to the weighted member and surface assembly through the chord :. 10. The spring balance 12 is mounted centrally on the plate 14, such that a :..::: person may stand on the plate with one foot either side of the spring balance.
The drive assembly 16 comprises a chord 17 attached to the spring balance 12. The chord passes through an eyelet 19, allowing the user to pull the chord vertically upwards and exert a horizontal force on the weighted member 4 through the spring balance 12.
S.....
* 20 The pulling mechanism 10 further comprises adjustment screws 21, which are used to adjust the height of the spring balance 12 with respect to the plate 14, in order to ensure that the force exerted on the weighted member 4 is substantially parallel to the subject surface.
The spring balance 12 is contained within a guide block 32. The guide block 32 ensures that the spring balance 12 is in the correct position with respect to the weighted member 4 and the surface assembly 6. The guide block 32 further comprises a low friction support sleeve 34. The low friction support sleeve 34 supports the spring balance 12 and also allows spring balance 12 to move within guide block 32.
Referring to Figure 3, there is shown a detailed view of the weighted member 4 and surface assembly 6. The weighted member 4 is loaded with one or more weights 18, which may be interchanged according to the weight required to be applied during the test. Thus, the weight may be increased or decreased depending on the test being carried out by the apparatus. As noted above, the surface assembly 6 has a lower surface, to which portions of shoe soles, car tyres and the like are fastened so as to allow the grip they provide on a subject surface to be tested.
The weighted member as shown in Figures 1 and in more detail in Figure 3 is pivotably connected to the surface assembly 6 by a hinge mounting 20. In this way, the weighted member 4 may be tilted at an angle to the surface assembly 6 and the test surface. The weighted member 4 comprises an extension plate 22, extending from the edge of the weighted member 4 opposite the hinge mounting 20. The extension plate 22 extends at an acute angle to the surface assembly 6 and bears upon a generally cylindrical guide 24. The guide is moveable with respect to the surface assembly 6 and the * extension plate 22. Movement of the guide 24 towards the hinge mounting 20 moves the weighted member 4 out of parallel with the surface assembly 6. S....
* 20 Movement of the guide 22 is achieved manually using a screw assembly 26 comprising a screw 28 having one end attached to the guide 22 and a knob at its second, free end.
In use on an inclined subject surface, the orientation of the weighted member 4 with respect to the surface assembly 6 is adjusted using the screw assembly so that the weight of the weighted member bears substantially vertically through the surface assembly. In this way, the apparatus can be used to simulate a person standing on or moving up or down the inclined surface. In order to better simulate a person moving across an inclined surface, the weighted member may be mounted so as to be rotatable with respect to the surface assembly, in order to ensure that the weight is applied substantially vertically to the surface assembly. I. p. p... p * * . p S* * ** *
I..... * . p. p * p *..
p.....
S
1 2455564
APPARATUS FOR MEASURING THE FRICTION OF A SURFACE AND
METHOD OF OPERATING THE SAME
The present invention relates to an apparatus for the measurement/comparison of the friction of a variety of different surfaces.
When a surface becomes wet, or contaminated with other substances, the friction of the surface, that is its resistance to slip, will change. This often leads to slips and falls by persons walking or running on the surface. This can be especially hazardous in the work place when working with heavy machinery and the like.
Apparatus for measuring the coefficient of friction of a surface and the surface *:* 15 profile are well known in the art. Most are complex and very expensive, making them inaccessible to many smaller companies. * *. * S.
*....: * Examples of known apparatus and devices are disclosed in DE 4201124; DE 199221760; CA 1273221; DE 202006025416; DE 10028708; CA 2527082; *** : 20 WO 0229376; US 6430520; JP 20042714119; CN 2645077Y; and JP * S 2005337918.
It has also been found that obtaining a value for the coefficient of friction for various surfaces is not generally helpful as most people have no idea what friction value is necessary to achieve a non slip condition under variable states of contamination. Rather, those responsible for slip safety require a means of direct comparison of how a specific material, such as a shoe sole or tyre tread, will react with a given surface and to be able to evaluate directly the improvement obtained by a range of custom safety surface treatments.
Health a safety laws increasingly require employers to provide the best equipment possible to prevent staff from slipping and injuring themselves.
This is increasingly important where employees are required to carry out work in areas where floors inevitably become wet or impregnated with other substances, which may make people using them more prone to slip and fall.
Accordingly, there is a need for a simple to use and inexpensive device that will allow a user to evaluate the best combination of materials, such as footwear or tyre tread, and surface covering available in order to prevent slippage.
According to a first aspect of the present invention, there is provided an apparatus for measuring the grip of a subject surface, comprising a weighted member, means for applying a force to move the weighted member with :* i respect to the subject surface, and means for measuring the force applied to *, * move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto * which the weight of the weighted member is applied, wherein the surface assembly comprises means to allow the test surface to be interchanged. * 20
is....
* The function of the apparatus is to compare the slip resistance of surfaces, in particular those surfaces used by both vehicular and pedestrian traffic. The apparatus allows a user to rapidly compare a range of materials when in contact with the subject surface and to determine their relative resistances to slippage when moved along the subject surface. The apparatus is particularly advantageous in that the user is not required to determine or calculate such factors as coefficients of friction in order to may the comparison, but rather obtains a direct comparison of the slip resistance of the various test materials and/or the subject surface under different conditions.
In use, a force is applied to move the apparatus along the subject surface with the test surface contacting the subject surface and providing a resistance to such movement. The device incorporates means for measunng a force, such as a measuring gauge, with the facility to read the forces applied to the apparatus, including the applied force after the slippage has occurred. In use, the slip resistance is measured using a variety of test pieces, for example actual footwear or the soles of footwear, to enable a comparison to be made of the suitability of such footwear in a real life situation. Comparison can also be made of existing surfaces under different conditions, for example wet or dry, clean or contaminated. In such a case, the apparatus may be provided with a standard test surface on the surface assembly to contact the subject surface. The standard test surface will typically have known properties. The response of the subject surface under the differing conditions may then be tested using the standard test surface. * S
The apparatus comprises a weighted member, which provides a load acting through the test surface and bearing on the subject surface. Provision may be ****** * made to vary the load on the test surface, and/or also the distribution of the load, to simulate real foot movement. In this way, the apparatus allows the 20 risk of slippage to be determined under different load conditions, for example at various stages in the stride of a person walking or running.
The apparatus also enables the comparison of various non-slip surfaces used to minimise slip risk, for example coatings or coverings that may be applied to a floor or walkway. In use, such non-slip surfaces may be assessed using one or a variety of test surfaces affixed to the apparatus itself.
As noted above, the apparatus further comprises means for measuring the force applied to move the apparatus along the subject surface. The means for measuring the applied force may be fixed. More preferably, the said means is adjustable in aspect, in order to keep the measuring plane of the means parallel to the subject surface for consistent readings. In this way, the apparatus is also able to compare surfaces in sloping situations, that is movement uphill, downhill and/or across the slope of the subject surface.
The weighted member may be of any suitable weight to allow the required comparison of surface properties to be obtained. In one embodiment, the weighted member is of sufficient weight that it simulates the weight of a person. This may allow a more accurate indication of real-life risks of slippage to be obtained. However, the maximum applied weight may be limited by other components of the apparatus, for example the means for measuring the applied force. In this respect, spring balances can prove difficult to operate when coupled to weights approaching those of a typical person. In such a case, a maximum weight of 50kg has been found to be suitable for carrying outthetests. *... * * ***
The weighted member may be of a fixed weight. Preferably, the weight of the weighted member is adjustable, so as to allow a user to test the grip of a surface for a specific individual or set of circumstances. This may be :. achieved, for example, by adding or removing weights onto the weighted *:..:: 20 member, in accordance with either a specific weight of an individual or an average weight to give a more general figure.
The test surface may be the surface of any material that it is desired to test for slippage on the subject surface. In one embodiment, the test surface is in the form of a sole of a shoe. This allows a user to test and compare specific shoes soles so as to allow selection of the shoe sole most suited to the environment. In one arrangement, the surface assembly comprises a means for supporting a complete shoe, such as a last, whereby the test may be carried out using an entire shoe, rather than just the sole portion.
An alternative embodiment of the apparatus allows portions of tyres to be affixed to the surface assembly, to allow the performance of tyre tread patterns and compositions to be examined.
The test surface may be flat or may be contoured, such as is the case of the sole of a shoe.
The means for measuring the force applied to move the weighted member may be any suitable means. One convenient means comprises a spring balance. The spring balance may be of any design commonly known in the art and such balances are available commercially.
The spring balance is preferably contained within,, guide block. The guide block ensures the spring balance is maintained In the correct position with respect to the weighted member and the surface assembly. The guide block preferably further comprises a support sleeve. The support sleeve is S preferably manufactured from a low friction material, such as PTFE. The S..... . * * support sleeve allows the spnng balance to move freely within the support :. sleeve.
S.....
* The means for applying force to move the weighted member may act through any part of the apparatus. The means is preferably adapted to pull the apparatus. The means preferably acts to move the weighted member by applying a force in a lateral direction that is substantially parallel to the subject surface. The means for applying the force should be arranged to provide a repeatable application of force in a manner that is consistent from test to test.
The means for applying a force to the weighted member is preferably automated, again to ensure that an equal force is applied each time the apparatus is used. Alternatively, the means for applying the force may be manually operated. In its simplest form, the means for applying the force comprises a handle or the like which may be gripped by the user to apply a force through the measuring means, such as a spring balance, directly to the apparatus.
In this respect, one preferred arrangement is to have the measuring means, such as a spring balance, mounted to a plate. One end of the measuring means is connected either directly or indirectly to the weighted member, for example by a chord. The second end of the measuring means is provided with a chord or the like, such that a force may be applied to the weighted member through the measuring means. One particularly preferred arrangement is to have the measuring means mounted on a plate sufficiently large for the user to stand with one foot either side of the measuring means and apply the force to the weighted member by pulling upwards on a chord or the like. The underside of the plate is preferably coated with a high friction ". 15 material or formed to provided a high friction with the subject surface, in order to prevent the plate from moving during the test. The plate may be flexible, for example by being hinged, in order to accommodate a rough or irregular subject surface. p
As noted, the apparatus allows subject surfaces to be tested that are p.....
* S horizontal or inclined. When testing the performance of a test surface on an inclined subject surface, a particular issue arises when the test surface is the.
sole of a shoe. In general, a person walking or running up, down or across a slope will keep their body substantially vertical, with the angle of the slope being accommodated by the joints in the legs, in particular the ankle joints. In order to more accurately simulate the movement of a person on an inclined subject surface, the apparatus preferably allows the weighted member to be moved relative to the surface assembly, such that the weight may be applied at an angle to the surface assembly and the test surface. In this way, the apparatus may be oriented on an inclined subject surface such that the weight of the weighted member is acting substantially vertically.
Accordingly, in a further aspect, the present invention provides an apparatus for determining the grip properties of a test surface in contact with a subject surface, the apparatus comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable.
Any suitable means may be used to change the angle of orientation of the weighted member to the surface assembly. One preferred arrangement is to have the weighted member pivotably mounted with respect to the surface ". 15 assembly. e.
In order to better simulate a person moving across an inclined surface, the weighted member is preferably mounted so as to be rotatable with respect to the surface assembly. In this way, the weighted member may be both rotated and tilted relative to the surface assembly in order to achieve a vertical action * of the weight.
The apparatus preferably comprises means for locking the weighted member in relation to the surface assembly.
Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which: Figure 1 shows a perspective representation of the apparatus from the side; Figure 2 is a representation of a more detailed view of the means for applying a force to the apparatus of Figure 1 from above; and Figure 3 is a representation of a more detailed view of the weighted member of the apparatus of Figure 1.
The embodiments of the present invention will be described in relation to shoe soles and tyres. However, it is to be understood that the apparatus may be applied to many other situations where the grip of other surfaces may need to be measured and compared.
Referring to Figure 1, there is shown a preferred embodiment of the apparatus, generally indicated as 2, as viewed from the side. The apparatus :..::: comprises a weighted member 4 in the form of a generally flat plate, to which *...
weights can be applied and removed as desired.
Attached to the underside of weighted member 4 is a surface assembly 6, :. again in the form of a generally flat plate. A shoe sole, or part of a tyre or the * like can be attached to the underside of the surface assembly 6 so as to S....
* 20 enable the user to evaluate the surface to be tested. The surface assembly 6 is formed to allow the surface to be tested to be readily mounted to the apparatus and removed, to allow a plurality of tests to be conducted in quick succession. The shoe sole or tyre to be tested is releasably secured to the underside to the surface assembly 6 by suitable means, for example screws, bolts, clips or the like.
A pulling mechanism 8 is attached to one end of the surface assembly 6, by means of a cord 10. The pulling mechanism 8 comprises a spring balance 12 for measuring the force required to move the weighted member 4 and the surface assembly 6. In use, the weighted member 4 and the surface assembly 6 are moved by the pulling mechanism 8 using the cord 10. The spring balance 12 records the force required to move the combined weighted member 4 and surface assembly 6 for the surface to be tested.
Referring to Figure 2, there is shown a detailed view of the pulling mechanism, generally indicated as 10. The pulling mechanism 10 is mounted on a plate 14. The plate 14 is coated with a high friction material on its underside for contact with the subject surface and to prevent movement of the plate 14 during the test.
As noted, the pulling mechanism 10 comprises a spring balance 12. The pulling mechanism 10 further comprises a drive assembly 16, by which a force is applied to the weighted member and surface assembly through the chord :. 10. The spring balance 12 is mounted centrally on the plate 14, such that a :..::: person may stand on the plate with one foot either side of the spring balance.
The drive assembly 16 comprises a chord 17 attached to the spring balance 12. The chord passes through an eyelet 19, allowing the user to pull the chord vertically upwards and exert a horizontal force on the weighted member 4 through the spring balance 12.
S.....
* 20 The pulling mechanism 10 further comprises adjustment screws 21, which are used to adjust the height of the spring balance 12 with respect to the plate 14, in order to ensure that the force exerted on the weighted member 4 is substantially parallel to the subject surface.
The spring balance 12 is contained within a guide block 32. The guide block 32 ensures that the spring balance 12 is in the correct position with respect to the weighted member 4 and the surface assembly 6. The guide block 32 further comprises a low friction support sleeve 34. The low friction support sleeve 34 supports the spring balance 12 and also allows spring balance 12 to move within guide block 32.
Referring to Figure 3, there is shown a detailed view of the weighted member 4 and surface assembly 6. The weighted member 4 is loaded with one or more weights 18, which may be interchanged according to the weight required to be applied during the test. Thus, the weight may be increased or decreased depending on the test being carried out by the apparatus. As noted above, the surface assembly 6 has a lower surface, to which portions of shoe soles, car tyres and the like are fastened so as to allow the grip they provide on a subject surface to be tested.
The weighted member as shown in Figures 1 and in more detail in Figure 3 is pivotably connected to the surface assembly 6 by a hinge mounting 20. In this way, the weighted member 4 may be tilted at an angle to the surface assembly 6 and the test surface. The weighted member 4 comprises an extension plate 22, extending from the edge of the weighted member 4 opposite the hinge mounting 20. The extension plate 22 extends at an acute angle to the surface assembly 6 and bears upon a generally cylindrical guide 24. The guide is moveable with respect to the surface assembly 6 and the * extension plate 22. Movement of the guide 24 towards the hinge mounting 20 moves the weighted member 4 out of parallel with the surface assembly 6. S....
* 20 Movement of the guide 22 is achieved manually using a screw assembly 26 comprising a screw 28 having one end attached to the guide 22 and a knob at its second, free end.
In use on an inclined subject surface, the orientation of the weighted member 4 with respect to the surface assembly 6 is adjusted using the screw assembly so that the weight of the weighted member bears substantially vertically through the surface assembly. In this way, the apparatus can be used to simulate a person standing on or moving up or down the inclined surface. In order to better simulate a person moving across an inclined surface, the weighted member may be mounted so as to be rotatable with respect to the surface assembly, in order to ensure that the weight is applied substantially vertically to the surface assembly. I. p. p... p * * . p S* * ** *
I..... * . p. p * p *..
p.....
S
Claims (14)
1. An apparatus for measuring the grip of a subject surface, comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the surface assembly comprises means to allow the test surface to be interchanged.
2. The apparatus according to claim 1, wherein the weighted member :..::: simulates the weight of a person. * ***
3. The apparatus according to either of claims I or 2, wherein the weight applied by the weighted member is adjustable. I.
4. The apparatus according to any preceding claim, wherein the test * 20 surface comprises a surface that simulates the sole of a shoe or the tread portion of a tyre.
5. The apparatus according to any preceding claim, wherein the means for measuring the force applied to move the weighted member comprises a spring balance.
6. The apparatus according to any preceding claim, wherein the means for applying a force to move the weighted member is adapted to pull the weighted member relative to the subject surface.
7. The apparatus according to claim 6, wherein the means for applying a force to move the weighted member is adapted to pull the weighted member in a lateral direction substantially parallel to the subject surface.
8. The apparatus according to any preceding claim, wherein the means for applying a force to move the weighted member is automated.
9. The apparatus according to any of claims I to 7, wherein the means for applying a force to move the weighted member is manual.
10. The apparatus according to any preceding claim, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable. 0**S
11. An apparatus for determining the grip properties of a test surface in contact with a subject surface, the apparatus comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force I.....
* 20 applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable.
12. The apparatus according to claim 11, wherein the weighted member is pivotably mounted with respect to the surface assembly.
13. The apparatus according to either of claims 11 or 12, wherein the weighted member is rotatably mounted with respect to the surface assembly.
14.An apparatus for measuring the grip of a subject surface substantially as hereinbefore described having reference to any of Figures 1, 2 or 3. I.
IS
I S S... S. * I ** * S.
p..... * S I. p * I *S. *
I.....
S
14.An apparatus for measuring the grip of a subject surface substantially as hereinbefore described having reference to any of Figures 1, 2 or 3. I.
IS
I S S... S. * I ** * S.
p..... * S I. p * I *S. *
I.....
S
1. An apparatus for measuring the grip of a subject surface, comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the surface assembly comprises means to allow the test surface to be interchanged.
2. The apparatus according to claim 1, wherein the weighted member :..::: simulates the weight of a person. * ***
3. The apparatus according to either of claims I or 2, wherein the weight applied by the weighted member is adjustable. I.
4. The apparatus according to any preceding claim, wherein the test * 20 surface comprises a surface that simulates the sole of a shoe or the tread portion of a tyre.
5. The apparatus according to any preceding claim, wherein the means for measuring the force applied to move the weighted member comprises a spring balance.
6. The apparatus according to any preceding claim, wherein the means for applying a force to move the weighted member is adapted to pull the weighted member relative to the subject surface.
7. The apparatus according to claim 6, wherein the means for applying a force to move the weighted member is adapted to pull the weighted member in a lateral direction substantially parallel to the subject surface.
8. The apparatus according to any preceding claim, wherein the means for applying a force to move the weighted member is automated.
9. The apparatus according to any of claims I to 7, wherein the means for applying a force to move the weighted member is manual.
10. The apparatus according to any preceding claim, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable. 0**S
11. An apparatus for determining the grip properties of a test surface in contact with a subject surface, the apparatus comprising a weighted member, means for applying a force to move the weighted member with respect to the subject surface, and means for measuring the force I.....
* 20 applied to move the weighted member, the apparatus further comprising a surface assembly having a test surface for contacting the subject surface and onto which the weight of the weighted member is applied, wherein the angle of orientation of the weighted member with respect to the surface assembly is adjustable.
12. The apparatus according to claim 11, wherein the weighted member is pivotably mounted with respect to the surface assembly.
13. The apparatus according to either of claims 11 or 12, wherein the weighted member is rotatably mounted with respect to the surface assembly.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0724401A GB2455564B (en) | 2007-12-14 | 2007-12-14 | Apparatus for measuring the friction of a surface and method of operating the same |
| PCT/GB2008/004124 WO2009077733A2 (en) | 2007-12-14 | 2008-12-15 | Apparatus for measuring the friction of a surface and method of operating the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0724401A GB2455564B (en) | 2007-12-14 | 2007-12-14 | Apparatus for measuring the friction of a surface and method of operating the same |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0724401D0 GB0724401D0 (en) | 2008-01-30 |
| GB2455564A true GB2455564A (en) | 2009-06-17 |
| GB2455564B GB2455564B (en) | 2011-05-04 |
Family
ID=39048094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0724401A Active GB2455564B (en) | 2007-12-14 | 2007-12-14 | Apparatus for measuring the friction of a surface and method of operating the same |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2455564B (en) |
| WO (1) | WO2009077733A2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2677298A1 (en) * | 2012-06-20 | 2013-12-25 | Institut National de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture (IRSTEA) | Device and method for determination of a friction force at the interface between two surfaces |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ITVR20110149A1 (en) * | 2011-07-14 | 2013-01-15 | Vibram Spa | DEVICE AND METHOD TO PERFORM ADHERENCE TESTS |
| JP7463022B2 (en) | 2021-01-22 | 2024-04-08 | 株式会社モアグリップ | Slip resistance measuring device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4813266A (en) * | 1987-09-21 | 1989-03-21 | Nash Patrick L | Method and apparatus for computing surface coefficients of friction |
| US5245856A (en) * | 1992-01-13 | 1993-09-21 | Randy Pazzaglia | Portable testing device for measuring static and dynamic drag fractors |
| US5736630A (en) * | 1997-02-11 | 1998-04-07 | Welner; Jerome M. | Slip friction measurement and recording apparatus |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4187714A (en) * | 1977-10-26 | 1980-02-12 | Wright State University | Surface friction tester |
| US4524602A (en) * | 1984-03-07 | 1985-06-25 | Moore Milton D | Accident reconstruction device |
| US4798080A (en) * | 1987-06-10 | 1989-01-17 | Brungraber Robert J | Portable tester for measuring slip resistance |
| US5259236A (en) * | 1992-05-27 | 1993-11-09 | William English | Tribometer |
-
2007
- 2007-12-14 GB GB0724401A patent/GB2455564B/en active Active
-
2008
- 2008-12-15 WO PCT/GB2008/004124 patent/WO2009077733A2/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4813266A (en) * | 1987-09-21 | 1989-03-21 | Nash Patrick L | Method and apparatus for computing surface coefficients of friction |
| US5245856A (en) * | 1992-01-13 | 1993-09-21 | Randy Pazzaglia | Portable testing device for measuring static and dynamic drag fractors |
| US5736630A (en) * | 1997-02-11 | 1998-04-07 | Welner; Jerome M. | Slip friction measurement and recording apparatus |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2677298A1 (en) * | 2012-06-20 | 2013-12-25 | Institut National de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture (IRSTEA) | Device and method for determination of a friction force at the interface between two surfaces |
| FR2992424A1 (en) * | 2012-06-20 | 2013-12-27 | Inst Nat De Recherche En Sciences Et Technologies Pour L'environnement Et L'agriculture Irstea | METHOD FOR DETERMINING A FRICTION FORCE AT THE INTERFACE BETWEEN TWO SURFACES |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2455564B (en) | 2011-05-04 |
| WO2009077733A3 (en) | 2009-08-13 |
| GB0724401D0 (en) | 2008-01-30 |
| WO2009077733A2 (en) | 2009-06-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Chang et al. | The role of friction in the measurement of slipperiness, Part 2: Survey of friction measurement devices | |
| Grönqvist et al. | Evaluation of three portable floor slipperiness testers | |
| US9470619B2 (en) | Intrinsically-calibrated tribometer | |
| US5259236A (en) | Tribometer | |
| Grönqvist et al. | The validity and reliability of a portable slip meter for determining floor slipperiness during simulated heel strike | |
| US20190369005A1 (en) | Device for measuring and testing footwear traction | |
| Manning et al. | A method of ranking the grip of industrial footwear on water wet, oily and icy surfaces | |
| WO2009077733A2 (en) | Apparatus for measuring the friction of a surface and method of operating the same | |
| CN218074972U (en) | Evaluation device for balance ability evaluation | |
| EP1358466B1 (en) | Device for measuring the static and/or dynamic friction coefficient of an artificial grass lawn for sports fields | |
| US4081989A (en) | Device for measuring the stress of tangential friction of a shoe on a surfacing for the ground | |
| Kulakowski et al. | Evaluation of performance of three slip resistance testers | |
| US3641807A (en) | Traffic machine for carpets | |
| US4798080A (en) | Portable tester for measuring slip resistance | |
| WO2008038001A2 (en) | Monitoring apparatus | |
| JP4585351B2 (en) | Static friction measuring device | |
| US4759209A (en) | Portable tester for measuring slip resistance | |
| JP2010085350A (en) | Kit and method for measuring friction resistance | |
| JPH0221240A (en) | Sole flooring slippage testing machine | |
| EP2546631B1 (en) | Device and method to perform grip tests | |
| Bowman et al. | Comparison of standard footwear for the oil wet ramp slip resistance test | |
| CN111759052A (en) | Method and device for measuring static friction coefficient of sole | |
| Malviya et al. | Development of a novel biomedical device for shoe traction safety characterization | |
| Leffler | The changing world of slip-and-fall analysis | |
| AU2004270767B2 (en) | An apparatus and method for measuring surface properties |