Method of forming an inlaid pattern in an asphalt surface
In one embodiment the method comprises the steps of providing a first template having a predetermined pattern; impressing the first template into the asphalt surface when the asphalt surface is in a pliable state to form an impression therein; removing the first template from the asphalt surface to expose the impression; providing a second template having a predetermined pattern matching the pattern of the first template; inserting the second template into the impression; and fixing the second template in position within the impression to form the inlaid pattern. The second template may consist of a preformed thermoplastic grid having a color and/or texture contrasting with the asphalt surface. In another embodiment the second template may include a light source for illuminating the template after it has been fixed in position. A heating method is described for gradually heating large asphalt surfaces using a reciprocating bank of infrared heaters to thermally fix the thermoplastic grid in place.
This application relates to a method of forming an inlaid pattern in an asphalt surface. The pattern may be selected for functional or decorative purposes.
BACKGROUNDVarious methods for forming patterns in asphalt surfaces are known in the prior art. The Applicant is the owner of U.S. Pat. No. 5,215,402 which describes a method of forming a pattern in an asphalt surface using a removable template. The template is compressed into a pliable asphalt surface to imprint a predetermined pattern simulating, for example, the appearance of bricks, cobblestones, interlocking paving stones or the like. The template is then lifted clear of the asphalt surface and the asphalt is allowed to harden. A thin layer of a cementitious coating may be applied to the imprinted asphalt to enhance the brick and mortar or other desired effect.
In the above-described method the template does not remain inlaid within the asphalt surface. The visual effect is created by the combination of the imprinted pattern and the decorative coating. One drawback to this method is that the decorative coating may wear off over time, particularly in high traffic areas.
It is known in the prior art to install traffic markings on asphalt surfaces. However, such markings typically project above the asphalt surface. In regions receiving frequent snowfalls during the winter months traffic markings may be removed or damaged by snowplow usage.
Another known method for producing traffic markings involves grinding grooves in asphalt surfaces and then pouring into the grooves a hot molten material which is allowed to set in place. However, this is a very time consuming procedure and is not well suited for forming complicated patterns or covering large surface areas.
The need has therefore arisen for improved methods and materials for inlaying patterns in asphalt surfaces.
SUMMARY OF INVENTIONIn accordance with the invention, a method of forming an inlaid pattern in an asphalt surface is disclosed. The method includes the steps of:
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- (a) providing a first template having a predetermined pattern;
- (b) impressing the first template into the asphalt surface when the asphalt surface is in a pliable state to form an impression therein;
- (c) removing the first template from the asphalt surface to expose the impression;
- (d) providing a second template having a predetermined pattern matching the pattern of the first template;
- (e) inserting the second template into the impression; and
- (f) fixing the second template in position within the impression to form the inlaid pattern.
The method may include the step of heating the asphalt surface in situ at the impression site prior to impressing the first template into the asphalt surface.
The step of fixing the second template in position within the impression comprises heating the second template to cause the second template to bond to the asphalt surface. For example, the second template may be heated to a temperature within the range of about 100° F.-400° F. and more preferably within the range of 150° F.-350° F.
The second template may comprise a pre-formed thermoplastic grid of unitary construction. The color of the grid may be selected to contrast with the color of the asphalt surface. In another embodiment the grid may include a light source for lighting the grid once it has been set in place in the asphalt surface. In other embodiments the grid may be luminescent or flourescent, such as when subjected to light of a suitable wavelength. In one embodiment the first and/or second templates may include a plurality of frame elements defining open areas therebetween, the open areas comprising approximately 50-90% of the total surface area of each template.
In one embodiment the second template may comprise an upper surface which is substantially flush with the surface of the asphalt when the second template is fixed in position. Alternatively, a portion of the second template may be raised above the asphalt surface or recessed below the asphalt surface when it is set in place.
The second template may be formed from a plurality of frame elements each having a relatively narrow width to facilitate compression of the template into the asphalt surface. For example, the frame elements may have a width between ¼ inch and 4 inches.
In a further alternative embodiment the asphalt surface may be heated in situ and the template may be compressed into the asphalt surface directly while the asphalt is in a pliable state and without deforming the desired predetermined pattern. The template is then fixed in place as in the embodiment described above. Templates adapted for impression forming and inlaid applications are described herein.
In one aspect of the invention a method of forming an inlaid pattern in an asphalt surface is described comprising:
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- (a) gradually heating the asphalt surface in situ until it is in a pliable state by periodically passing an infrared heater thereover;
- (b) forming an impression in the asphalt surface;
- (c) introducing a settable material into the impression; and
- (d) allowing the settable material to set within the impression to form the inlaid pattern.
In another aspect of the invention the method of forming an inlaid pattern comprises:
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- (a) forming an impression in the asphalt surface;
- (b) placing a thermoplastic template into the impression; and
- (c) gradually heating the thermoplastic template by periodically passing at least one heater thereover until the template adheres to the asphalt surface.
The heater is preferably a reciprocating infrared heater capable of heating a relatively large surface area, such as greater than 10 square feet, while permitting visual monitoring of the work site. For example, a heating apparatus having a frame extendable over the asphalt surface may be provided and the infrared heater(s) may reciprocate on the frame to gradually heat the asphalt surface and/or the inlaid template.
BRIEF DESCRIPTION OF DRAWINGSIn drawings which illustrate embodiments of the invention, but which should not be construed as restricting the spirit or scope of the invention in any way,
Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense.
With reference to the drawings, this application relates to methods and apparatus for imprinting an asphalt surface 10. As used in this patent application “asphalt” means a paving compound for constructing roads, driveways, walkways and the like which consists of a combination of bituminous binder, such as tar, and an aggregate, such as sand or gravel.
As shown in
Template 12 is compressed into asphalt surface 10 when surface 10 is in a pliable state. For example, template 12 may be compressed into hot, freshly rolled asphalt (which is typically on the order of 150°-400° F. depending upon the type of ashpalt). Alternatively, a portable surface heater 14 may be provided (
Template 12 may be compressed into surface 10 with a mechanical compactor, such as a vibrating plate compactor 16 or a drum roller (
The next step in the process is to provide a second template 20 configured to fit within impression 18. As shown in
Second template 20 is positioned within impression 18 as shown in
In one embodiment of the invention templates 12 and 20 are formed from a plurality of frame elements 13 which are relatively narrow in width and are arranged in a grid (
The thickness of frame elements 13 is also variable depending upon the application. The preferred thickness range is between 20-160 mil with 40-130 mil being the most preferred range. If the frame elements are very thin template 20 will be overly fragile. Conversely, if frame elements 13 are too thick templates 12, 20 will be difficult to compress into place. The optimum size and dimensions of frame elements 13 may depend in part on the pliability of asphalt surface 10 (i.e. whether the asphalt is relatively coarse or mastic in composition)
As shown in
The final step in the installation procedure is to fix second template 20 in position within impression 18. In the embodiment illustrated in
Another possible means for fixing template 20 within impression 18 is by the use of conventional glue adhesives. For example, impression 18 could be coated with a glue adhesive prior to the placement of template 20 therein. The step of fixing template 20 in position could therefore include applying the glue and allowing the glue sufficient time to set. Alternatively template 20 may comprise a tear-off layer which may be removed on site to expose an adhesive surface capable of bonding to asphalt surface 10.
In one possible embodiment of the invention, template 20 may consist of reflective material suitable for designating pedestrian crosswalks, turning lanes and the like. In another embodiment template 20 may include a light source or LED display for illuminating template 20 in its inlaid position, such as for safety or decorative purposes. Similarly, template 20 may be formed from flourescent material or material which is luminescent when subjected to light of a suitable wavelength (such as ultraviolet light). In another embodiment template 20 may be constructed from a skid-resistant material.
After template 20 has been inlaid, asphalt surface 10 may optionally be treated with a clear protective sealer. For example, the sealer could be formulated to protect surface 10 from oxidization and moisture damage, thereby preventing premature aging and discoloration of the patterned surface. The sealer could be an acrylic sealer commonly used in other applications to coat cementitious substrates.
In an alternative embodiment of the invention shown in
FIGS. 4(a) and 4(b) illustrate apparatus useful for carrying out the alternative method of the invention described above in an automated fashion. In the illustrated embodiment first template 20 is sufficiently flexible that it may be wound around a spool 22 mounted on a vehicle 24. Vehicle 24 also includes a drum roller 26 for progressively compressing template 20 into asphalt surface 10 as template 20 is unwound from spool 22. Portable surface heaters 14 move in advance of and behind vehicle 24 to pre-heat and re-heat the asphalt surface.
As will be apparent to a person skilled in the art, in an alternative embodiment of the invention template 12 could be provided on a drum roller rather than being a physically separate apparatus. That is, the means for forming impression 18 in asphalt surface 10 could be a surface contacting portion of compressive apparatus 16 itself. However, template 20 must be capable of being separated from compressive apparatus 16 since it remains inlaid within impression 18 as described above and shown, for example, in
As shown in
In one embodiment heaters 40 move through three cycles per minute (each cycle being a traversal of truck 38 from housing 36 to the distal end of rails 32 and back again). An important advantage of the heating method of
Further, heating apparatus 30 allows the operator to visually monitor the work site during the heating operation. For example, in use templates 20 may be manufactured in mats approximately 2′ by 2′ in size for ease of handling. Multiple templates 20 may be arranged to cover a large surface area. The templates 20 could be arranged so that the frame elements 13 (
As will be appreciated by a person skilled in the art, the gradual heating method shown in
In a further embodiment of the invention, the applicant's method could be employed to form an inlaid pattern in asphalt surface 10 wherein only the edge portion(s) of the template or other inlaid marking are inlaid. For example, a thermoplastic inlaid traffic marking having a gently curved upper surface could be provided. An impression 18 could be formed in surface 10 conforming to the contour of the periphery of the marking. Impression 18 could be formed so that only edge portions of the marking are inlaid to ensure that the edges will not be caught by snow plows in regions having winter snowfalls. Further, the curvature of the traffic marking could enhance the reflectivity of the thermoplastic material to improve traffic safety.
In one embodiment of the invention the gradual heating method of
In still further alternative embodiments of the invention heating apparatus 30 may be modified to include one or more heat sensors for sensing the temperature of asphalt surface 10. The heat sensors could be mounted on truck 38 to travel over surface 10 and scan the temperature thereof. Apparatus 30 may also include a controller for switching off one or more of the heaters 40 in the heater bank depending upon the measured surface temperature. For example, once the surface temperature achieves a target value, some of the heaters 40 could be switched off to prevent further heating and possible scorching of the asphalt while other heaters 40 could remain on to maintain the surface temperature at or near the target value.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
Claims
1. A method of forming an inlaid pattern in an asphalt surface comprising:
- (a) providing a first template having a predetermined pattern;
- (b) impressing said first template into said asphalt surface when said asphalt surface is in a pliable state to form an impression therein;
- (c) removing said first template from said asphalt surface to expose said impression:
- (d) providing a second template having a predetermined pattern at least partially matching the pattern of said first template;
- (e) inserting said second template into said impression; and
- (f) fixing said second template in position within said impression to form said inlaid pattern.
2. The method as defined in claim 1, further comprising the step of heating said asphalt surface prior to impressing said first template into said asphalt surface.
3. The method as defined in claim 1, wherein the step of fixing said second template in position within said impression comprises heating said second template to cause said second template to bond to said asphalt surface.
4. The method as defined in claim 3, wherein said second template is heated to a temperature within the range of approximately 100°-400° F.
5. The method as defined in claim 3, wherein said second template is heated to a temperature within the range of approximately 150°-350° F.
6. The method as defined in claim 1, wherein said second template comprises a pre-formed thermoplastic grid.
7. The method as defined in claim 1, wherein said second template is of unitary construction.
8. The method as defined in claim 1, wherein said second template has a color contrasting with the color of said asphalt.
9. The method as defined in claim 1, wherein said second template comprises a light source for illuminating said second template after said template is fixed in position within said impression.
10. The method as defined in claim 1, wherein said second template is luminescent.
11. The method as defined in claim 1, wherein said second template is flourescent.
12. The method as defined in claim 1, wherein said second template comprises an upper surface, wherein said upper surface is substantially flush with the surface of said asphalt when said second template is fixed in position.
13. The method as defined in claim 1, wherein said second template comprises an upper surface, wherein said upper surface is recessed below the surface of said asphalt when said second template is fixed in position.
14. The method as defined in claim 1, wherein said second template comprises an upper surface, wherein said upper surface projects above the surface of said asphalt when said second template is fixed in position.
15. The method as defined in claim 1, wherein second template comprises a grid formed from a plurality of frame elements, wherein said frame elements have a width less than 12 inches.
16. The method as defined in claim 15, wherein said frame elements have a width between ¼ inch and 2 inches.
17. A method of forming an inlaid pattern in an asphalt surface comprising:
- (a) providing a portable heating apparatus having a frame extendable over said asphalt surface and at least one heater movable on said frame;
- (b) gradually heating said asphalt surface in situ by moving said heater on said frame over said asphalt surface until said asphalt is in a pliable state;
- (c) providing a template having a predetermined pattern;
- (d) impressing said template into said asphalt surface when said asphalt surface is in said pliable state; and
- (e) fixing said template in position to form said inlaid pattern.
18. The method of claim 17 wherein said template is formed from a plastic material.
19. The method of claim 18, wherein said template is formed from a thermoplastic material.
20. The method of claim 17, wherein said template is formed from rubber.
21. The method as defined in claim 17, wherein said second template is of unitary construction.
22. The method as defined in claim 17, wherein said template has a color contrasting with the color of said asphalt.
23. The method as defined in claim 17, wherein said template comprises a light source for illuminating said template after it has been fixed in position within said asphalt surface.
24. The method as defined in claim 17, wherein said template is luminescent.
25. The method as defined in claim 17, wherein said template is flourescent.
26. The method as defined in claim 17, wherein said template comprises an upper surface, wherein said upper surface is substantially flush with the surface of said asphalt when said second template is fixed in position.
27. The method as defined in claim 17, wherein said template comprises an upper surface, wherein said upper surface is recessed below the surface of said asphalt when said template is fixed in position.
28. The method as defined in claim 17, wherein said template comprises an upper surface, wherein said upper surface projects above the surface of said asphalt when said template is fixed in position.
29. The method as defined in claim 17, wherein template comprises a grid formed from a plurality of frame elements, wherein said frame elements have a width less than 12 inches.
30. The method as defined in claim 29, wherein said frame elements have a width between ¼ inch and 4 inches.
31. (Currently Amended) The method as defined in claim 30, wherein said frame elements have a width between ⅜ inch and 2 inches.
32. The method as defined in claim 17, wherein the thickness of said template is between 20-160 mil.
33. The method as defined in claim 32, wherein the thickness of said template is between 40-130 mil.
34. The method as described in claim 1, further comprising coating said asphalt surface with a clear sealant after said second template is fixed in position.
35. A method of forming an inlaid pattern in an asphalt surface comprising:
- (a) gradually heating said asphalt surface in situ until it is in a pliable state by repeatedly passing an infrared heater thereover;
- (b) forming an impression in said asphalt surface;
- (c) introducing a settable material into said impression; and
- (d) allowing said settable material to set within said impression to form said inlaid pattern.
36. The method as defined in claim 35, wherein said settable material is permanently fixed within said impression.
37. The method as defined in claim 35, wherein said settable material is thermoplastic.
38. The method as defined in claim 36, further comprising providing a template having a predetermined pattern and wherein the step of introducing a settable material into said narrow impression comprises placing said template into said impression.
39. The method as defined in claim 35, wherein said impression is between ¼ inch and 4 inches in width.
40. (Currently Amended) The method as defined in claim 35, wherein said inlaid pattern is decorative.
41. A template suitable for impression into a pliable asphalt surface comprising a thermoplastic grid formed from a plurality of frame elements defining a plurality of open areas therebetween, wherein each of said frame elements has a width less than 4 inches and wherein said open areas comprise approximately 50-90% of the total surface area of said template.
42. The template as defined in claim 41, wherein said frame elements have a width between ⅜ inch and 2 inches.
43. The template as defined in claim 42, wherein the thickness of said template is between 20-160 mil.
44. The template as defined in claim 43, wherein the thickness of said template is between 40-130 mil.
45. The template as defined in claim 41, wherein said template is formed from a material selected from the group consisting of a flourescent material, a luminescent material and a luminous material.
46. A method of forming an inlaid pattern in an asphalt surface comprising:
- (a) forming an impression in said asphalt surface;
- (b) placing a thermoplastic template into said impression; and
- (c) gradually heating said thermoplastic template by periodically passing at least one heater thereover until said template adheres to said asphalt surface.
47. The method as defined in claim 46, wherein said impression is formed in said asphalt surface when said asphalt surface is in a pliable state.
48. The method as defined in claim 46, wherein said heater is an infrared heater.
49. The method as defined in claim 48, wherein said asphalt surface is allowed to partially cool after each successive pass of said infrared heater.
50. The method as defined in claim 49, wherein said infrared heater is supported from a rail extending above said asphalt surface, wherein said heater reciprocates on said rail between first and second positions.
51. The method as defined in claim 50, wherein the surface area covered by said template and traversed by said heater exceeds approximately 10 square feet.
52. The method as defined in claim 2, wherein said asphalt surface is heated in situ.
53. The method as defined in claim 16, wherein said template comprises a plurality of frame elements defining a plurality of open areas therebetween, wherein said open areas comprise approximately 50-90 % of the total surface area of said template.
Type: Application
Filed: Dec 3, 2002
Publication Date: Apr 28, 2005
Inventor: Patrick Wiley (Chilliwack)
Application Number: 10/497,354