EP3134576B1

EP3134576B1 - Pot hole repair

Info

Publication number: EP3134576B1
Application number: EP14799866.0A
Authority: EP
Inventors: Graham Anthony TAYLOR; Douglas Graham JACKSON; Craig Steven JACKSON
Original assignee: Individual
Current assignee: JACKSON, CRAIG STEVEN; JACKSON, DOUGLAS GRAHAM; TAYLOR, GRAHAM ANTHONY
Priority date: 2013-11-15
Filing date: 2014-11-14
Publication date: 2020-09-23
Anticipated expiration: 2034-11-14
Also published as: WO2015071676A1; GB2520308A; GB201320213D0; EP3134576A1

Description

The present invention relates to the maintenance and repair of road and other surfaces and in particular to the repair of pot holes.
Any road, pavement or other surface designed to sustain traffic (e.g. of motorised vehicles, bicycles or people) requires maintenance and repair. Surfaces used worldwide include asphalt, concrete, tarmac, and composite types. It can be an expensive and continuous challenge to maintain the quality of the road surfaces, and in many countries the problem is acute. For example, the condition of UK roads is deteriorating due to a combination of harsh winters and insufficient maintenance.
This is an extensive problem and has not been effectively addressed. Public finances often do not run to full scale re-surfacing. Particularly during difficult economic conditions, road maintenance budgets are limited or cut, which can lead to more pot holes being left unfilled. This is clearly a safety problem for the travelling public. Unfilled potholes can cause significant damage to cars and other vehicles, and can cause accidents.
Costs are rising, and local authorities are often required by law to address any issues associated with pot holes within a short period of time from them being reported.
Improvements and cost savings in surface maintenance and repair are of great interest to not only the public sector but also the private sector. Whether carrying out repairs on privately owned roads or contracted to carry out repairs on public roads, it is important to carry out repairs quickly and in a cost-effective manner, and it is also important that the repairs are of sufficient quality and structurally competent so that they stand the test of time.
Particularly where there is a backlog of required repairs, short term "quick patch" and mend repairs have a tendency to be adopted, for safety reasons and as protection against compensation claims. Over the long term, the "quick patch" repairs have been identified as being vastly more expensive than more competent repair.
Before discussing the details of the present invention, known repair procedures will now be described in more detail.
To our knowledge there are fundamentally at least three types of procedure which are commercially utilised in the repair of pot holes:

a. The "slap and dash method" involves little or no preparation of the pot hole to receive surfacing material and consists of placing and compacting surfacing material in the pot hole. This is most often used for an emergency repair.
b. The "cutting method" uses a Stihl or similar saw to cut around the hole, generally in a square or rectangle, and then the existing material is removed within the cut perimeter with breakers/ jack hammers and replaced with new compacted material.
c. The "planing method" uses a planer which utilises a longitudinal breaking/ scouring /planing action to cut and remove the defective material. This machine is generally utilised for replacing longer defective areas of pavement and is not considered cost effective for pot hole repairs.

The advantages and disadvantages of each system are as follows

a. The "slap and dash method" is quick and requires minimal time to undertake and therefore less disruption to traffic, and uses relatively unskilled labour. However, the repair has a short life time and therefore is not cost effective.
b. The "cutting method" utilises fairly unskilled labour and "off the shelf" available equipment. However, there is generally significant noise and dust associated with the cutting and removing of material operation, a diligent workforce is required, over cut on corners creates weak points in the pavement which are prone to disintegration, and a rectangular repair is not the most stable solution. There are also safety issues associated with using saws in a public environment.
c. The "planing method" provides good results and can remove material from defective areas. However, it requires costly plant and equipment on site, skilled labour operatives, and more extensive traffic management. It only tends to be cost effective on longer lengths of defective pavement. Furthermore it may require Stihl saw or similar cutting of the ends of the planed section, and therefore comes with the associated disadvantages as described above.

Aside from these methods there are numerous documents which disclose other arrangements which do not seem to have been adopted commercially due to various limitations. For example, WO 2011/124887 refers to a pot hole repairing machine with a rotational cutting head. This document discloses a rotating linear blade, which in practice will not be the most effective for use on roads, particularly where surfaces are made from asphalt or similar durable materials.
US 4,968,101 discloses a vertical asphalt and concrete miller. It is stated to be a multipurpose rotary cutting machine and refers to disparate applications including "concrete milling, road surface planing, post hole digging, cutting tree stump roots and pothole repair". It contains separate disclosures of various distinct types of cutting heads each with a particular purpose. For example, one arrangement, used primarily for asphalt and sub-surface material removal, contains a cutting head which is a shaft with cutting bits along the vertical extent of said shaft. Another arrangement, used "to remove bumps and smooth the road surface", is a planing head; we infer that this arrangement would require not only rotational movement but also translational movement as the positioning of the bits as illustrated in this document would otherwise leave part of the surface unplaned. A further arrangement is used to cut around manhole castings and other items.
KR 2013 0019731 A discloses a road maintenance apparatus having a circular cutting apparatus, a grinding apparatus, a vacuum suction apparatus, a loading unit, a crane and an adhesive accommodation unit. The circular cutting apparatus has a blade unit on its undersurface to form a circular installation groove by cutting. The grinding apparatus forms a square-shaped installation groove by grinding or grinds an upper protrusion of a precast block installed in the installation groove. The vacuum suction apparatus sucks up material generated by cutting of the circular cutting apparatus. The crane lifts up a precast block from the loading unit and installs it in the groove. The adhesive accommodation unit accommodates an adhesive to fix a precast block to the installation groove.
The present invention brings improvements over the above-mentioned methods of pot hole repair, and addresses problems and shortcomings in various known methods and products.
From a first aspect the present invention provides a rotary cutting head for pothole repair comprising a plate with peripheral cutting teeth for cutting a circle around the pothole and inner grinding teeth for grinding out material within the circle, wherein the inner grinding teeth are located in a plurality of angular and radial positions, and are not on the same radial line, characterised in that the inner grinding teeth (26) are neither located in a purely linear nor a purely rotational manner, but have random locations spread across the plate.
In the present invention, the grinding teeth are located across the base of the cutting head, rather than in a purely linear manner. In this way the teeth are oriented in a different way to those along a single blade line. In a single blade line, such as that disclosed in WO 2011/124887 , teeth are located along a single straight line, and together form a blade; additionally, they are not located on the base of a plate. In contrast, in the present invention, there are grinding teeth which are located in a plurality of angular and radial positions. The grinding teeth are offset from each other. The grinding teeth are positioned so that, when the plate is rotated, they grind out material in a substantially uniform manner across the entirety of the circular cross-section.
Planing teeth such as those disclosed in for example US 4,968,101 are not effective when used in a purely rotational manner as they do not cover the surface in a sufficiently uniform manner. The present invention permits the cutting of a suitable hole around a pot hole using rotational action without translational motion.
An essential feature of the present invention is that not all the grinding teeth are on the same radial line. Spacing apart the grinding teeth across the cross-sectional area of the cutting head enhances the grinding action, balances the device and makes it more durable, and minimises the time required for grinding out road material.
The cutting head may take the form of a disc which in use spins in the horizontal plane, with cutting teeth around the circumference, and grinding or milling teeth attached to the underside of the disc.
The present invention allows the efficient preparation of a cylindrical hole which may then be filled.
The formation of a circular section is advantageous because it avoids over cut problems which are associated with the "cutting method" described above. By "over cut" is meant the cutting of lines beyond the boundary of the hole being prepared. The continuous circular boundary cut in accordance with the present invention avoids the presence of exterior cuts which can leave residual weaknesses which are more susceptible to weathering.
The cutting and subsequent filling of a square or rectangular hole results in a repair which may be feathered at corners and edges which as a consequence may be where future weathering or damage may initiate. In contrast the cutting and filling of a vertically sided cylindrical hole results in a repair which is more durable.
Whilst the cutting of a circular boundary brings advantages as described above, yet further advantages arise from the combination of this feature with the use of teeth to mill or grind out material within that circle. These teeth (referred to herein as grinding teeth, scouring teeth or milling teeth) are typically positioned across the underside of the cutting head. They loosen and gouge out the road surface material in a step which is integral with the circular cutting step. This means that no separate step of loosening and removal of the road material is required.
The apparatus may be vehicular mounted, e.g. on a lorry or other vehicle, thereby in some embodiments utilising hydraulics on the vehicle as "donor" hydraulics, which enables works to be undertaken in a relatively short time. Alternatively the apparatus may be used as or with an individual pack, e.g. an individual hydraulic power pack; in that way the work can still be carried out quickly but further flexibility is provided.
The work may be undertaken within a confined space thereby eliminating the dust hazard if used in the public domain.
The invention is flexible in that it is able to cater for repairs of different sizes by using different sizes of cutting heads and able to cater for different depths of repair with the same equipment. Preferred sizes include between 0.5 and 2 m diameter e.g. between 0.75 and 1.5 m diameter though other sizes are possible. Preferred depths are up to 500mm, e.g. 30mm to 300mm, e.g. 50mm to 100mm though other depths are possible.
Prototypes have been tested and have been shown to allow quicker repair than traditional methods currently used.
An additional benefit is that the present invention gives "surety" on the amounts of material to be excavated and used. Pothole repairing companies currently face problems due to the over- and under-ordering of surfacing material used in the repairs; material can be difficult to obtain at short notice if it is under-ordered (due to the relatively small amounts utilised) and disposal of excess amounts from over-ordering is costly. The controlled and defined circular cut means that it is clear exactly how much material is required; this improves efficiency and reduces costs.
Further advantages of the use of central grinding teeth in combination with peripheral cutting teeth are reduction of noise (no jack hammers, breakers etc. are required) and removal of the requirement for additional equipment and additional operatives associated with using conventional breakers to break out the material from the area to be repaired.
The benefits of quicker repair should not be underestimated. Closure of a road or part thereof causes considerable inconvenience and economic penalty and has safety implications. If a repair can be completed within a reduced time from those at present, crash cushion vehicles can be utilised in many situations on the highways, thus excluding the requirement for costly traffic management and with the added advantage of less disruption to the travelling public. Any reduction in the amount of time required is beneficial, from a commercial and safety point of view.
The device makes a vertical circular perimeter cut to the surfacing and also cuts the material within the circumference, to depths of surfacing as required.
Preferably the grinding or scouring teeth extend downwards to approximately the same extent as (or less than) the perimeter teeth. This ensures that the extent of the hole is defined by a clean-cut cylindrical surface.
Preferably one or more of the grinding teeth extend radially outwards to, or near to, the perimeter, so as to ensure that grinding occurs to the extent of the perimeter cut.
Sufficient teeth are provided so as to allow for effective cutting and grinding of a cylindrical hole. The number of circumferential cutting teeth may for example be within the range of 1 to 20, e.g. between 2 and 10, e.g. between 3 and 7. Optionally the number of circumferential cutting teeth may be between 1 and 10, e.g. between 1 and 5, e.g. between 1 and 3, per metre of circumference. The number of grinding teeth may for example be between 7 and 50, e.g. between 8 and 30, e.g. between 10 and 20. Optionally the number of grinding teeth may be between 30 and 100, e.g. between 40 and 80, e.g. between 50 and 60, per square metre of cross-sectional area. All of these possible numbers are however merely examples and the number of teeth may be outside these ranges, depending for example on the nature of the road surface, and the nature and arrangement of the teeth.
According to the invention, the grinding teeth appear to have random locations spread across the plate. In another, non-claimed variant, the grinding teeth may be positioned in a spiral manner. In any case the teeth are positioned so as to ensure that rotation brings about substantially overall grinding of the cylindrical hole across the circular cross-section.
A further advantage of positioning grinding teeth in a plurality of radial positions is that it reduces the need for the teeth to push or sweep a large bulk of material. In contrast, a blade such as that disclosed in WO 2011/124887 would need to act on all the material in front of it, i.e. effectively a half-cylinder, and will encounter very high resistance.
The teeth may be straight (i.e. perpendicular to the plate) or angled, or there may be a combination of straight or angled teeth. Optionally, one, some or all of the grinding teeth may be angled. Optionally, one, some or all of the cutting teeth may be angled.
Preferably one or some, optionally most or all, of the grinding teeth, are angled and/or located in such a manner as to enhance the grinding action and/or to excavate material and guide it towards the perimeter.
Optionally, means may be provided to collect, e.g. by vacuum, the ensuing debris from the excavation. The material is finely ground and can be recycled rather than going to landfill, thus reducing the carbon footprint of the repair and bringing additional economic benefit.
The perimeter teeth and/or the internal teeth may be integral to the plate or alternatively may be replaceable such that new teeth may be used to replace worn teeth. Preferably the grinding teeth are distinct teeth rather than being arranged in the form of a blade. The circumferential teeth may be distinct teeth or may be arranged in the form of a saw blade.
Optionally one or more of the inner grinding teeth may be positioned and/or angled so that it/ they function as the peripheral cutting teeth.
The teeth can be made from a variety of materials which may include hardened steels and alloys. The tips of the teeth may be of tungsten carbide or a hardened steel or alloy. Use may be made of available proprietary "teeth".
The plate may be made of steel or an alloy, optionally a mild steel.
The plate may be rotated by a hydraulic feed driving a hydraulic motor which in turns rotates a shaft attached to the circular plate.
Optionally there may be a cut out valve on the hydraulic drive system to prevent the system components being overloaded
The plate may be rotated at speeds which may be varied, for example to suit prevailing site conditions and density of materials being removed. Rotational speeds may be variable and typically may be between 30 and 200 rpm, however rotational speeds may vary below and above these values to suit prevailing conditions.
The cutting head may be a single plate. Alternatively, the cutting head may be a composite item comprising a hub and one or more rings which may be used together to provide tools of different sizes. In this way one or more rings can be fastened, e.g. bolted, onto the hub and/or onto other rings. The further rings may be bolted on according to requirements. For example the apparatus may be tailored as required on site when it becomes apparent exactly what size diameter is required. Or may be adjusted in accordance with a pre-determined procedure, e.g. cutting a batch of holes of one size followed by cutting a batch of holes of a different size.
A composite apparatus brings further advantages in that it avoids the need to carry several interchangeable complete cutting heads, and allows parts of the apparatus to be replaced or repaired without needing to service the whole apparatus.
Different types of ring may be used to provide a variety of different types of composite cutting head, and to allow tailoring according to requirements. For example, a composite cutting head may comprise one or more "spacer" ring which does not have teeth. In this way the apparatus may be adapted to for example allow the cutting of a circular line around a structure, e.g. ironworks, e.g. a manhole, without grinding inside the circle (as this would damage the ironwork). In another example, a central circular area may be left unground, and an annular hole may be ground between two concentric circles.
In order to accommodate pavement repairs around and/or to facilitate repairs to ironworks, the cutting head, if composed of several rings, may have one or more cutting / grinding rings protrude below the level of the main disc by means of spacer blocks to enable either a perimeter single circular cut, several concentric cuts or several concentric cuts with the grinding out of the material between them.
The apparatus may be enclosed, for example with a shielding enclosure, so as to contain any excavated material within the enclosure.
The apparatus may be used so as to core two or more separate cylindrical holes which may overlap and/or which may be linked by linear cuts.
From a further aspect the present invention provides a method of pothole repair comprising excavating a cylindrical hole around a pothole using the cutting head of the present invention.
The present invention will now be described in more specific and non-limiting detail with reference to the following examples and figures in which:

Figures 1 to 3 show prior art methods of pot hole repair, in cross section (figures 1a, 2a, 3a and 3b) and plan view (figures 1b, 2b and 3c);
Figure 4 shows, schematically, a cutting head in accordance with the present invention from the side (figure 4a) and from below (figure 4b);
Figure 5 is a photograph of a cutting head in accordance with the present invention;
Figures 6a and 6b show in cross section and plan view a vehicle with a cutting head in accordance with the present invention;
Figure 6c shows a cutting head (rotating disk) in use;
Figure 7 shows a pot hole with material cut away and at the periphery; and
Figures 8a and 8b show a cutting plate different from the present invention.

Some prior art methods of pot hole repair are exemplified in figures 1 to 3.
The slap and dash method shown in figure 1 entails simply filling a pot hole 1 with asphalt or other material. Edge 2 of the pot hole, which usually has a feathered edge, is typically not treated in any way prior to filling, so the repair has a short life expectancy.
Figure 2 shows the use of a Stihl saw 6 to cut around pot hole 1. Material 7 is removed using breakers to leave a rectangular cut to depth 8.
Disadvantageously, there is a surfacing over cut 10 at the corners. The pot hole is replaced with a rectangular fill 11.
Figure 3 shows a longer pot hole 14 (typically it would be longer than illustrated) and the use of a longitudinal apparatus 16 with cutters on a continuous tread to plane the area. Additional material 18 may be cut out at the edges. Cutting at the end of the planed sections typically results in over cut 21 at the corners. Again, the treated hole 20 is filled with asphalt or other material.
One example of a cutting head in accordance with the present invention is shown in figure 4. This has a rotating shaft 24 and a cutting disk unit 28 carrying internal teeth 26 which may be angled or straight and outside perimeter cutting teeth 25 which are typically either below or level with the internal teeth. Holes 32 may optionally be present to assist in the dispersal of material when the depth of the hole cut is greater than the depth of the cutter. The two types of teeth 25, 26, on plate 28, can also be seen in the photograph (figure 5).
With reference to figures 6a, 6b and 6c, cutting head 28 is positioned over a pot hole 1, and is connected via rotating shaft 24 to a hydraulic or other motor 37 (two possible positions are indicated in figure 6a) on vehicle (e.g. lorry, JCB, bob cat, etc.) 36. Means 38 are provided to lower and raise the cutting disc. A vacuum pipe 40 may be used to remove material and a screen 41 may be positioned around the cutting area. Means 42 may be provided to adjust the horizontal position of the cutting disc. In use, cut material 44 may be transported to the outside of the disc.
Figures 7a and 7b show the effects of the machine cutting the area for the pot hole repair. These depict the pot hole 1, the perimeter of the cut 47, and material transported from its original location 48 to location 44 at the outside of the perimeter.
With reference to figures 8a and 8b a variant comprises a cutting unit 28 made up of multiple components which may reside on a backing plate 54 and may be connected with connectors 53. Ring sections 57 may be bolted on or removed to suit the diameter of the hole required and edge cut teeth 58 may be relocated to accommodate different hole diameters 55A,B,C.

Non-limiting example of pothole repair procedure

a. The diameter of the hole and depth of hole to be cut are determined, and the appropriate cutting disc chosen.
b. The machine is located with the donor vehicle and machine adjustable mountings over the area to be cut.
c. The machine is lowered to approximately 50mm over the area to be cut, rotated at the appropriate speed then slowly lowered, cutting of the perimeter edge and cutting/grinding/ planing/milling of the material within the perimeter cut circumference commencing.
d. Lowering continues until the prescribed depth of material is cut.
e. The material cut or excavated within the perimeter may be dispersed to the perimeter of the hole excavated. This will depend upon the angle of the cutting/milling/planing heads used with the plate circumference.
f. The material so cut may be removed by several methods including a vacuum machine attached to the donor vehicle.
g. The donor vehicle being re-located if angled cutting/milling/planing heads are not in use.
h. A system of interchangeable plates or single plates may be used as alternatives to accommodate variations in the size of holes to be cut.

Claims

A rotary cutting head (28) for pothole repair comprising a plate with peripheral cutting teeth (25) for cutting a circle around the pothole and inner grinding teeth (26) for grinding out material within the circle, wherein the inner grinding teeth are located in a plurality of angular and radial positions, and are not on the same radial line, characterised in that the inner grinding teeth (26) are neither located in a purely linear nor a purely rotational manner, but have random locations spread across the plate.
A rotary cutting head (28) as claimed in claim 1 wherein at least some of the inner grinding teeth (26) are offset from each other.
A rotary cutting head (28) as claimed in any preceding claim wherein the diameter of the circle is between 0.5 m and 2 m.
A rotary cutting head (28) as claimed in any preceding claim comprising grinding teeth (25, 26) which are angled.
A rotary cutting head as claimed in any preceding claim in the form of a single plate.
A rotary cutting head as claimed in any of claims 1 to 4 in the form of a composite item comprising a hub and one or more rings instead of the plate, optionally wherein one or more of the rings do not carry teeth.
Apparatus (36) comprising a rotary cutting head (28) as claimed in any preceding claim and means for removal of the excavated material.
Apparatus (36) as claimed in claim 7 wherein the means for removal comprise vacuum means (40).
Vehicle (36) comprising a rotary cutting head (28) as claimed in any of claims 1 to 6 or an apparatus as claimed in claim 7 or claim 8.
Use of a rotary cutting head (28) as claimed in any of claims 1 to 6, or an apparatus (36) as claimed in claim 7 or claim 8, or a vehicle as claimed in claim 9, for repairing a pothole.
Use as claimed in claim 10 wherein excavation is carried out to a depth of 50 to 100 mm.
Method of repairing a road or pavement comprising cutting a cylindrical hole (47) around a pot hole (1) using a cutting head (28) as claimed in any of claims 1 to 6, removing cut material (48), and filling and compacting asphalt and/or other material into the cylindrical hole.