GB2256585A - Improvements in or relating to tread strips and mat elements - Google Patents

Abstract

An entrance mat 10 in its preferred embodiment has a tread surface 31 provided by a plurality of rectangular section tread strips 18 of fabric reinforced rubber arranged to extend parallel with one another, the side faces of each tread strip being provided with a longitudinally extending groove 35 and each tread strip being supported by a C-section rigid channel section support strip 11 having in cross-section a mouth region (25; see Figure 2) which is defined by a pair of confronting lip formations (23, 24; see Figure 2) arranged to interengage with respective grooves in opposite sides of a tread strip. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO MATS This invention relates to a mat of the kind comprising a plurality of first strips of substantially rigid material, for example of aluminium or a plastics material such as polyvinyl chloride or polypropylene, and a plurality of second strips, typically of a substantially flexible material such as natural or synthetic rubber and having an embedded reinforcement fabric, the first and second strips being arranged to extend parallel with one another and with the second strips appearing interposed alternately between the first strips as viewed at the wear surface of the mat.

In one well-established entrance mat of the abovereferred type the second strips each lie interposed between a respective pair of first strips and the first and second strips are secured together alternately in a side-by-side relationship by means of one or more connecting elements, such as wires, which pass through aligned apertures in the first and second strips.

In a mat of the kind referred to in the preceding paragraph it will be appreciated that the spacing of successive first strips depends upon the width of the respective interposed second strips. Where the second strips are of the flexible kind having embedded layers of reinforcement fabric arranged with the layers to lie substantially transverse to the plane of the mat and provide a wear-resistant primary tread surface, such strips are formed typically by cutting strips from a sheet of material comprising a flexible polymeric matrix having embedded therein one or more layers of fabric reinforcement. Thus the thickness of the sheet material defines the width of each strip when in situ in a mat; accordingly any variation in thickness of the sheet material is likely to result in a variation of the spacing of successive pairs of the substantially rigid first strips in the resulting mat.

Often, and particularly for mats covering only a small area, a slight variation between the spacing of successive pairs of first strips is not significant.

However, where two or more of the mats require to be installed in a manner in which the strips of a first mat are to be aligned lengthwise with respective strips of a second mat it is aesthetically very important that all of the strips of one mat appear aligned with those of the adjacent second mat. This is not readily achievable if there is random variation in the thickness of the sheet material used to form the second, tread strips of the two mats.

Hitherto attempts have been made to achieve alignment of the strips in a pair of mats by carefully selecting lengths of flexible second strips which all have a substantially similar width. This, however, is a time-consuming operation and also poses a potential limitation on the extent to which all originally produced reinforced sheet material may be utilised to form the second, tread strips of a mat.

The present invention seeks to overcome or mitigate the aforedescribed problem and facilitate the provision of a mat in which there is a potentially good uniformity of alignment between two portions of the mat material when laid side-by-side with the strips of the respective mats arranged end-to-end.

In accordance with one of its aspects the present invention provides a mat element comprising a support strip of substantially rigid material and a tread strip supported by the support strip, said support strip being shaped to define an elongate channel which extends in the direction of the length of the strip and said channel having in cross-section a base portion the width of which is greater than that of a mouth portion, and said tread strip comprising in cross-section an elongate base portion which lies in the base portion of said channel, a head portion which lies outwards of said channel and between said head and base portions of the tread strip a neck portion located in the mouth portion of the channel.

The support strip preferably is provided with a pair of outwardly facing location faces whereby two mat elements of the invention may be retained directly adjacent one another in a side-by-side relationship or interconnected in a spaced relationship by one or more interposed spacer strips.

The location faces may have formations of a kind which allow two strips to be located one relative to the other in a manner that permits relative sliding of the strips, at least during initial assembly, but restrains separation of the strips in a direction transverse relative to their lengths. The invention teaches in particular that one of a pair of location faces on a support strip may have a tongue or like male formation and the other may have a complementary shaped groove or like female formation whereby two portions of said strip may be slid one relative to the other into an interlocked relationship.

The mouth of the support strip may be defined by an inwardly extending lip portion of the strip; preferably 'a pair of inwardly extending lips are provided and arranged to lie opposite one another, the lips extending towards one another from respective sides of the channel.

The support strip may be provided with two or more channels which extend side-by-side whereby a mat element may comprise a single support strip and a plurality of tread strips supported by that single support strip.

The tread strip may have a side face which is grooved or rebated thereby to define at least in part a neck portion for location of a lip portion of the tread strip; preferably each side face of the tread strip is grooved or rebated to provide for location of a pair of channel lip portions. It will be appreciated from the reference to rebated formations that the head portion need not necessarily have a width greater than that of the neck portion, though generally in order to provide a mat having a high percentage of its working, wear surface defined by upper surfaces of the tread strips it is envisaged that the head portion of each tread strip shall be of a width substantially equal to or even greater than that of the base portion.

In accordance with another of its aspects the present invention provides a mat tread strip comprising an elongate strip of polymeric material having a wear face and two side faces which depend from the wear face, the strip comprising in cross-section a head portion which carries or provides the wear face, a neck portion and a base portion, the width of the neck portion being less than the width of at least the base portion, and embedded within said polymeric material a plurality of layers of reinforcement arranged to extend in the direction of the length of the strip and to lie in planes substantially perpendicular to that of the wear face with the material of the reinforcement layers exposed at the wear face of the strip. Said tread strip may be shaped additionally to possess any of the tread strip features recited herein and in particular in the preceding paragraph.

The polymeric material of the tread strip preferably is substantially flexible and/or resilient.

Suitable materials include natural and synthetic rubber, and the reinforcement preferably is provided by discrete fabric layers. Suitable materials for forming the fabric layers include natural fibres and also synthetic fibres such as nylon.

Typically between 3 and 8, and more preferably between 5 and 6 fabric reinforcement layers are provided per centimetre width of tread strip.

Preferably the reinforcement layers each comprise elements such as yarns which in the tread strip lie at an inclined angle, typically 45 , relative to the length of the strip and with the elements of one layer preferably being inclined in a direction opposite that of the elements of an adjacent reinforcement layer.

Although reference is made. herein to the tread strips having a wear face, it is to be understood that in use of the tread strip, and even though the wear faces will in general provide the main load receiving area of the mat, the wear face does not necessarily exhibit a significant tendency to wear away. Thus, particularly where the tread strips are comprised by synthetic rubber having exposed at the wear face reinforcement of nylon fibres, even after extensive use and after being subject to extensive foot wiping action there may be no significant reduction in thickness of the tread strip.

The invention further provides a mat comprising a plurality of mat elements of the invention arranged with the elements extending parallel with one another in a side-by-side relationship. Subsequent to assembly of a plurality of mat elements in a side-by-side relationship they may be secured against movement one relative to the other. In the case of adjacent elements which are slid into position one relative to the other, subsequent to assembly, relative sliding may be restrained for example by local deformation of the support strip material. Likewise movement of a tread strip relative to a support strip may be restrained by location means such as a pin extending through the support strip into the tread strip in a direction transverse to the length of the mat element.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: Figure 1 is an end sectional view of part of a mat in accordance with the present invention; Figure 2 shows in detail a cross-sectional view of a support strip of Figure 1; Figure 3 is a cross-sectional view of a connecting element; Figures 4 and 5 are cross-sectional views of edge elements; Figure 6 is a cross-sectional view of a support strip of a mat element in accordance with another embodiment of the present invention, and Figure 7 is a longitudinal sectional view of a tread strip in the plane 7-7 of Figure 1 and part cut away.

An entrance mat 10 comprises a plurality of substantially rigid strip-like elements 11,12,13,14 arranged to extend parallel to one another in sideby-side relationship. Adjacent strips are interconnected by tongue 15 and groove 16 type formations described in more detail below.

Some of the strip-like elements are support strips 11 of mat elements 17 which each comprise also a tread strip 18. Other strip-like elements 12 are connecting elements which lie between and interconnect successive mat elements, and the extreme edges of the mat are provided with complementary shaped edge strips 13,14 (only one shown in Figure 1).

Each support strip 11 (see Figure 2) comprises a generally rectangularly shaped channel 19 having a base portion 20, two sidewall portions 21,22 and a pair of lip portions 23,24 which extend towards one another from opposite sidewall portions to define therebetween a mouth region 25. The support strip 11 is formed from extruded aluminium though other materials of a substantially rigid nature such as brass and plastics such as polyvinyl chloride may be used.

A right-hand sidewall portion 22 carries at its outer face an elongate tongue 15 comprised by a pair of hook-shaped formations 26. The outer face of the left-hand sidewall portion 21 carries a pair of limbs 27 which define therebetween the groove formation 16, each inner face 29 of the limbs being formed with a recess 28. The recesses 28 and the hook-shape formations 26 are of a complementary shape whereby two of the support strips 11 may be slid into side by-side relationship and restrained by the tongue and groove formations from separation away from one another in a direction perpendicular to their length.

Each tread strip 18 is comprised by a strip of rectangular cross-sectional shape and formed of synthetic rubber having woven fabric layers of nylon 30 (some only shown in Figure 1) embedded therein.

The strip has a width of 14.2 mm and eight of the fabric layers are uniformly spaced and embedded therein.

The layers of nylon extend in the direction of the length of the tread strip and lie in planes substantially perpendicular to the upper, wear face 31 of the wear strip. Each of the woven fabric layers comprises nylon warp elements which extend at 450 relative to the length of the strip and the warp elements of successive layers are inclined in opposite directions. The layers of nylon serve as reinforcement layers which stiffen the synthetic rubber material and also, ty virtue of being exposed at the wear face, provide an aesthetically pleasant appearance to the wear face together with good wear resistance properties.

The tread strip 18 has a base portion 19 which lies within the support strip channel 19, a neck portion 33 which lies in the mouth 25 of the channel 19 and a head portion 34 which lies outwards of the channel 19. The base portion 32 rests on the base portion 20 of the support strip 11 and sidewalls of the tread strip are each provided with an elongate groove 35 for location of respective lip portions 21,22. The groove is shown as being of a rectangular shape in cross-section but may alternatively be, for example, of a semi-circular cross-section.

The grooves 35 in each tread strip 18 are formed by drawing the strip between a pair of cutters at a predetermined spacing. Thus the width of the neck portion 33 may be closely controlled to match the width of the mouth portion 25 irrespective of the width of the wear face 31 or any variations between the widths of successive portions of the wear strip.

The support strip and tread strip of each mat element 17 are assembled by sliding the tread strips into the channels 19. Subsequent relative sliding is restrained by means of two pins inserted through the sidewall 21 to engage respective ends of the tread strip (see Figure 1 which shows one of the pins).

In the entrance mat portion illustrated in Figure 1 successive mat elements 17 are spaced apart by connecting elements 12 (see Figure 3) provided with tongue and groove-like formations corresponding to those described above in respect of the support strip 11. A right-hand edge of the mat portion shown in Figure 1 is provided with an edge strip 13 (see also Figure 5) having a groove-like formation to engage the tongue-like formation of the right-hand mat element 17. The edge strip thus covers the tongue-like formation of the right-hand mat element and provides a pleasant appearance to the edge of the mat. Similarly the other, left-hand edge of the mat (not shown) is provided with an edge strip 14 (see Figure 4) of a kind having a tongue-like formation.

Subsequent to assembly of the respective strips 11,12,13,14 by sliding one relative to another, the aluminium material thereof is indented, preferably at the underside of the strips, to locally deform the tongue and groove-like formations and thereby provide restraint against free relative sliding movement.

In another embodiment of the invention, illustrated with reference to Figure 6, use is made of an extruded aluminium support strip 61 substantially similar to the aforedescribed strip 11 except that the lip formations are of a specially selected profile. Each lip portion 62 has an end portion 63 which extends downwardly towards the base 64 of the channel 65.

Thus, each lip portion 62 presents a lower surface 66 of an undercut type shape.

The aforedescribed support strip 61 may be used to locate a tread strip substantially as described in respect of the preceding embodiment and having generally rectangularly shaped or semi-circular shaped grooves in cross-section. Alternatively the tread strip may be formed with grooves which tend to match at least the profile of a part of the undercut surface 66. It is believed that this facilitates very effective retention of the tread strips and improved resistance to any tendency for transverse movement of each wear face relative to a support strip 61. As in respect of the aforedescribed support strips 11, two or more of the support strips 61 may be interconnected directly to one another, as shown in detail in Figure 6, or they may be spaced by connecting strips.

It will be appreciated that the use of mat elements as described herein results in each tread strip being spaced apart from other tread strips by a distance determined by the dimensions of the substantially rigid support strips (and any connecting strips). Thus, the spacing is not subject to random variation as conventionally experienced in the case of strip-like matting having tread strips of varying widths arranged to alternate with rigid strips in an arrangement in which the spacing of the rigid strips is determined by the width of each tread strip. Thus, when two portions of a mat in accordance with the present invention are laid with the strips thereof end-to-end, there will be alignment of the ends of all the tread strips and the hitherto experienced problem of accumulated tolerance variations resulting in misalignment of the ends of tread strips is avoided.

Claims (16)

CLAIMS:

1. A mat element comprising. a support strip of substantially rigid material and a tread strip supported by the support strip, said support strip being shaped to define an elongate channel which extends in the direction of the length of the strip and said channel having in cross-section a base portion the width of which is greater than that of a mouth portion, and said tread strip comprising in cross-section an elongate base portion which lies in the base portion of said channel, a head portion which lies outwards of said channel and between said head and base portions of the tread strip at least one groove or rebated side face thereby to define at least in part a tread strip neck portion for location of the tread strip in the mouth portion of the support strip channel.

2. A mat element according to claim 1 wherein the support strip is provided with a pair of outwardly facing location faces whereby said strip may be located between two other strips.

3. A mat element according to claim 2 wherein said location faces are of a kind which allow said support strip to be located relative to another strip by relative sliding of the strips.

4. A mat element according to claim 2 or claim 3 wherein a location face of the support strip is provided with a tongue or like male formation.

5. A mat element acording to any one of claims 2 to 4 wherein a location face of the support strip is provided with a groove or like female formation.

6. A mat element according to claim 1 wherein the mouth portion of the support strip is defined by an inwardly extending lip formation.

7. A mat element according to claim 6 wherein the mouth of the support strip is defined by a pair of lips which lie opposite one another and extend one towards the other from respective sides of the channel.

8. A mat element according to any one of the preceding claims wherein the support strip comprises a plurality of channels arranged to extend. side-by-side and each locate a tread strip.

9. A mat element according to any one of the preceding claims wherein the tread strip comprises embedded layers of reinforcement material exposed at a wear face of the strip.

10. A mat element according to any one of the preceding claims wherein the base portion of the tread strip rests on and is supported by a lower wall of the elongate support strip channel.

11. A mat element according to any one of the preceding claims wherein the mouth portion of the support strip is defined at least in part by a lip portion having an undercut shape surface.

12. A mat element according to any one of the preceding claims wherein the tread strip comprises an elongate strip of polymeric material having a wear face and two side faces which depend from the wear face, the strip comprising in cross-section a head portion which provides the wear face, a neck portion and a base portion, the width of the neck portion being less than the width of at least the base portion, and embedded within the polymeric material a plurality of layers of reinforcement arranged to extend in the direction of the length of the strip and to lie in planes substantially perpendicular to that of the wear face.

13. A mat element comprising a support strip of substantially rigid material and a tread strip of substantially flexible material supported by the support strip, said support strip being shaped to define an elongate channel which extends in the direction of the length of the strip and said channel having in cross-section a base portion the width of which is greater than that of a mouth portion defined by the space between a pair of lips which lie opposite one another and extend one towards the other from respective sides of the channel, the tread strip comprising in cross-section an elongate base portion which lies in the base portion of said channel, a head portion which lies outwards of said channel and between said head and base portions of the tread strip a neck portion located in the mouth portion of the channel, the neck portion being defined by material of the tread strip lying between a pair of grooves formed one each in side faces of the tread strip, the tread strip comprising polymer material having a plurality of layers of reinforcement embedded therein and arranged to extend in the direction of the length of the strip and to lie in planes substantially perpendicular to that of an upper wear face of the strip, and said support strip being provided with a pair of outwardly oppositely facing location faces whereby said strip may be located between two other strip-like mat elements.

14. A mat element constructed and arranged substantially as hereinbefore described with reference to Figures 1 to 5 or Figure 6 of the accompanying drawings.

15. A mat tread strip comprising an elongate strip of polymeric material having a wear face and two side faces which depend from the wear face, the strip comprising in cross-section a head portion which carries or provides the wear face, a neck portion and a base portion, the width of the neck portion being less than the width of at least the base portion, and embedded within said polymeric material a plurality of layers of reinforcement arranged to extend in the direction of the length of the strip and to lie in planes substantially perpendicular to that of the wear face with the material of the reinforcement layers exposed at the wear face of the strip.

16. A mat tread strip constructed and arranged substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.