| CLAIMS: 1. A method for mitigating degradation of a wooden piece immersed in water, wherein the degradation is caused by the presence of microorganisms in the water, the method comprising driving into a water-exposed surface of the wooden piece a large number of staples made of a material comprising iron, wherein: - driving the staples into the water-exposed surface of the wooden piece comprises distributing the staples on the water-exposed surface with an homogeneous density of staples on the water-exposed surface and a deepness of driving of the staples into the wooden piece; and - the homogeneous density of staples and the deepness of driving of the staples are adjusted to produce, by means of a chemical reaction between the water and the iron of the staples when the water immerses the water- exposed surface, a homogeneous ferrous oxide barrier on and underneath the water-exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water, 2. A method as defined in claim 1, comprising adjusting a length of prongs of the staples as a function of a cross sectional dimension of the wooden piece to adjust accordingly the predetermined deepness of driving of the staples into the wooden piece. 3. A method as defined in claim 1 , comprising making the staples with wire material comprising about 90% iron. 4. A method as defined in claim 1 , comprising making the staples with wire material having a diameter of about 1.53 mm. 5. A method as defined in claim 1 , wherein: - the wooden piece is a wooden post with circular cross section having a diameter of at least 18 cm; - the staples comprises prongs having a length situated between 25 and 45 mm to adjust accordingly the predetermined deepness of driving of the staples into the wooden piece; and - distributing the staples on the water-exposed surface comprises situating the homogeneous density of staples on the water-exposed surface of the wooden post between 2100 and 6000 staples by square meter, 6. A method as defined in claim 1 , wherein: - the wooden piece is a wooden post with square cross section having a side dimension of at least 12 cm; - the staples comprises prongs having a length situated between 25 and 50 mm to adjust accordingly the predetermined deepness of driving of the staples into the wooden piece; and - distributing the staples on the water-exposed surface comprises situating the homogeneous density of staples on the water-exposed surface of the wooden post between 2100 and 6000 staples by square meter. 7. A method as defined in claim 1 , wherein distributing the staples on the water-exposed surface comprises forming on the water-exposed surface of the wooden piece a regular staggered pattern of staples. 8. A method as defined in claim 1 , wherein distributing the staples on the water-exposed surface comprises forming on the water-exposed surface of the wooden piece a regular rectangular pattern of staples. 9. A wooden piece for immersion in water and protected against degradation of the wooden piece caused by the presence of microorganisms in the water, comprising a water-exposed surface and a large number of staples driven into the water-exposed surface of the wooden piece and made of a material comprising iron, wherein: - the staples have a length and are distributed on the water-exposed surface with an homogeneous density of staples on the water-exposed surface; and - the homogeneous density of staples and the length of the staples are adjusted to produce, by means of a chemical reaction between the water and the iron of the staples when the water immerses the water-exposed surface, a homogeneous ferrous oxide barrier on and underneath the water- exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water, 10. The wooden piece of claim 9, wherein the staples have at least one prong and said at least one prong has a length adjusted as a function of a cross sectional dimension of the wooden piece. 11. The wooden piece of claim 9, wherein the staples are made of wire material comprising about 90% iron. 12. The wooden piece of claim 9, wherein the staples are made of wire material having a diameter of about 1.53 mm. 13. The wooden piece of claim 9, wherein the staples comprise two-prong staples. 14. The wooden piece of claim 9, wherein the staples comprise single-prong staples. 15. The wooden piece of claim 9, wherein: - the wooden piece is a wooden post with circular cross section having a diameter of at least 18 cm; - the staples comprises prongs having a length situated between 25 and 45 mm; and - the homogeneous density of staples on the water-exposed surface of the wooden post is situated between 2100 and 6000 staples by square meter. 16. The wooden piece of claim 9, wherein; - the wooden piece is a wooden post with square cross section having a side dimension of at least 12 cm; - the staples comprises prongs having a length situated between 25 and 50 mm; and - the homogeneous density of staples on the water-exposed surface of the wooden post is situated between 2100 and 6000 staples by square meter. 17. The wooden piece of claim 9, wherein the staples are distributed on the water-exposed surface of the wooden piece in accordance with a regular staggered pattern. 18. The wooden piece of claim 9, wherein the staples are distributed on the water-exposed surface of the wooden piece in accordance with a regular rectangular pattern. 19. The wooden piece of claim 9, wherein: - the wooden piece is a wooden post with circular cross section having a diameter of about 250 mm; - the staples have prongs with a length ranging from about 30 to about 40 mm; and - the staples are distributed on the water-exposed surface using orthogonal spacing values of 23.3 mm and 15.5 mm to form a regular staggered pattern. 20. The wooden piece of claim 9, wherein: - the wooden piece is a wooden post with circular cross section having a diameter ranging from about 250 mm to about 300 mm; - the staples have prongs with a length ranging from about 30 to about 40 mm; and - the stapies are distributed on the water-exposed surface using orthogonal spacing values of X=14.2 mm and 5.7 mm to form a regular staggered pattern. 21 , The wooden piece of claim 9, wherein: - the wooden piece is a wooden post with circular cross section having a diameter ranging from about 350 mm to about 400 mm; - the staples have prongs with a length of about 40 mm; and - the staples are distributed on the water-exposed surface using orthogonal spacing values selected from the group consisting of; 10 mm and 5,7 mm; 11.1 mm and 5.7 mm; or 12.5 mm and 5.7 mm to form a regular staggered or rectangular pattern. 22. A wooden piece immersed in water and protected against degradation of the wooden piece caused by the presence of microorganisms in the water, comprising a water-exposed surface and a large number of staples driven into the water-exposed surface of the wooden piece and made of a materia! comprising iron, wherein: - the staples have a length and are distributed on the water-exposed surface with an homogeneous density of staples on the water-exposed surface; - the wooden piece further comprises a homogeneous ferrous oxide barrier on and underneath the water-exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water; and - the homogeneous density of staples and the length of the staples are adjusted to produce the homogeneous ferrous oxide barrier by means of a chemical reaction between the water and the iron of the staples. |
FIELD
[0001] The present invention generally relates to protection of an immersed wooden piece. More specifically, the present invention is concerned with a method for mitigating degradation of a wooden piece immersed in water caused by the presence of microorganisms in the water, and the corresponding wooden piece.
BACKGROUND
[0002] Wooden posts are widely used to support structures located above water level, for example above a lake, a lagoon or sea. Such structures include, for examples, quays, piers, boardwalks and buildings. In operation, a portion of the wooden posts is immersed in water and is prone to degradation due to the action of the microorganisms present in the water.
[0003] Nails driven into water-exposed wooden surfaces have been used, as early as the 1400s in Venice, as a technique for maintaining or safeguarding wooden ships, such as commercial sailing ships, by restricting damages made by marine microorganisms to wood. The technique was probably imported to Venice from northern countries, such as Flanders, as a result of commercial exchanges between them. However, the technique had remained confined to the art of naval architecture.
[0004] In 1952, research has been conducted in Denmark for reproducing the above mentioned technique in order to get an insight as to its mechanisms of operation. However, this research has been confined to shipbuilding and harbor constructions. [0005] Nevertheless, there still exists a need for a method for mitigating the action of microorganisms on wooden material immersed in water, which is reproducible and operable to extend the durability of such immersed wooden material.
SUMMARY
[0006] According to the present invention, there is provided a method for mitigating degradation of a wooden piece immersed in water, wherein the degradation is caused by the presence of microorganisms in the water, the method comprising driving into a water-exposed surface of the wooden piece a large number of staples made of a material comprising iron, wherein:
- driving the staples into the water-exposed surface of the wooden piece comprises distributing the staples on the water-exposed surface with an homogeneous density of staples on the water-exposed surface and a deepness of driving of the staples into the wooden piece; and
- the homogeneous density of staples and the deepness of driving of the staples are adjusted to produce, by means of a chemical reaction between the water and the iron of the staples when the water immerses the water- exposed surface, a homogeneous ferrous oxide barrier on and underneath the water-exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water.
[0007] The present invention also relates to a wooden piece for immersion in water and protected against degradation of the wooden piece caused by the presence of microorganisms in the water, comprising a water- exposed surface and a large number of staples driven into the water-exposed surface of the wooden piece and made of a material comprising iron, wherein:
- the staples have a length and are distributed on the water-exposed surface with an homogeneous density of staples on the water-exposed surface; and
- the homogeneous density of staples and the length of the staples are adjusted to produce, by means of a chemical reaction between the water and the iron of the staples when the water immerses the water-exposed surface, a homogeneous ferrous oxide barrier on and underneath the water- exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water.
[0008] The present invention is further concerned with a wooden piece immersed in water and protected against degradation of the wooden piece caused by the presence of microorganisms in the water, comprising a water-exposed surface and a large number of staples driven into the water- exposed surface of the wooden piece and made of a material comprising iron, wherein:
- the staples have a length and are distributed on the water-exposed surface with an homogeneous density of staples on the water-exposed surface;
- the wooden piece further comprises a homogeneous ferrous oxide barrier on and underneath the water-exposed surface over a certain thickness into the wooden piece to protect the wooden piece against degradation caused by the presence of microorganisms in the water; and - the homogeneous density of staples and the length of the staples are adjusted to produce the homogeneous ferrous oxide barrier by means of a chemical reaction between the water and the iron of the staples.
[0009] The foregoing and other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] in the appended drawings:
[0011] Figure 1 is a front elevational view of a wooden piece immersed in water, with staples driven in a water-exposed surface of the wooden piece and with the staples lying in an horizontal plane; Figure 1A is a front elevational view of a wooden piece immersed in water, with staples driven in a water-exposed surface of the wooden piece and with the staples lying in a vertical plane; Figure 1B is a front eievational view of a wooden piece immersed in water, with staples driven in a water-exposed surface of the wooden piece and with the staples iying in a plane inclined with respect to the horizontal;
[0012] Figure 2 is an example of staple that can be driven into the wooden piece as illustrated in Figures 1 , 1A and 1B;
[0013] Figure 3 is a sectional view of the wooden piece of Figures 1 ,
1A and 1 B with a staple driven therein, the staple being surrounded by a ferrous oxide protective barrier; [0014] Figure 4 is a front elevational view of an immersed portion of a wooden piece, with a plurality of staples driven in the water-exposed surface thereof, wherein the staples lie in an horizontal plane and wherein each staple has a ferrous oxide ring around it; Figure 4A is a front elevational view of an immersed portion of a wooden piece, with a plurality of staples driven in the water-exposed surface thereof, wherein the staples lie in a vertical plane and wherein each staple has a ferrous oxide ring around it; Figure 4B is a front elevational view of an immersed portion of a wooden piece, with a plurality of staples driven in the water-exposed surface thereof, wherein the staples lie in a plane inclined with respect to the horizontal and wherein each staple has a ferrous oxide ring around it;
[0015] Figure 5 schematically illustrates a first example of distribution of staples for protection of a wooden post having a diameter of 250 mm, wherein the staples lie in an horizontal plane; Figure 5A schematically illustrates the first example of distribution of staples for protection of a wooden post having a diameter of 250 mm, wherein the staples lie in a vertical plane; Figure 5B schematically illustrates the first example of distribution of staples for protection of a wooden post having a diameter of 250 mm, wherein the staples lie in a plane inclined with respect to the horizontal;
[0016] Figure 6 schematically illustrates a second example of distribution of staples in a wooden post for use in the construction of a dock and having a diameter ranging from about 250 to about 300 mm, wherein the staples lie in a horizontal plane; Figure 6A schematically illustrates the second example of distribution of staples in a wooden post for use in the construction of a dock and having a diameter ranging from about 250 to about 300 mm, wherein the staples lie in a vertical plane; Figure 6B schematically illustrates the second example of distribution of staples in a wooden post for use in the construction of a dock and having a diameter ranging from about 250 to about 300 mm, wherein the staples lie in a plane inclined with respect to the horizontal;
[0017] Figure 7 schematically illustrates a third example of distribution of staples in a wooden post for use in supporting a signal and having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a horizontal plane; Figure 7A schematicaiiy illustrates the third example of distribution of staples in a wooden post for use in supporting a signal and having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a vertical plane; Figure 7B schematically illustrates the third example of distribution of staples in a wooden post for use in supporting a signal and having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in plane inclined with respect to the horizontal;
[0018] Figure 8 schematically illustrates a fourth example of distribution of staples in a wooden post for use in supporting a signal having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a horizontal plane; Figure 8A schematically illustrates the fourth example of distribution of staples in a wooden post for use in supporting a signal having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a vertical plane; Figure 8B schematically illustrates the fourth example of distribution of staples in a wooden post for use in supporting a signal having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a plane inclined with respect to the horizontal; and
[0019] Figure 9 schematically illustrates a fifth example of distribution of staples in a wooden post for use in supporting a signal having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a horizontal plane; Figure 9A schematically illustrates the fifth example of distribution of staples in a wooden post for use in supporting a signa! having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a vertical plane; Figure 9B schematically illustrates the fifth example of distribution of staples in a wooden post for use in supporting a signal having a diameter ranging from about 350 to about 400 mm, wherein the staples lie in a plane inclined with respect to the horizontal.
DETAILED DESCRIPTION
[0020] A method and system for mitigating degradation of a wooden piece immersed in water according to the non-restrictive illustrative embodiments will now be described.
[0021] More specifically, these non-restrictive illustrative embodiments are concerned with a method and system for mitigating the degradation of a wooden piece immersed in water, wherein the degradation is caused by the presence of microorganisms in the water. Staples at least partially made of iron are driven into a surface of the wooden piece exposed to water and on which the action of microorganisms needs to be mitigated. As the iron of the staples reacts with water to produce ferrous oxide (FeO) 1 rings of oxidation form around the staples and, with time, the rings overlap with one another so as to form a homogenous protective barrier on and underneath the water-exposed surface over a certain thickness of the wooden piece. The protective barrier operates as a result of the microorganisms being unable to metabolize ferrous oxide.
[0022] Referring now to Figures 1, 1A and 1B, a wooden post 10 is driven into the soil 12 at the bottom of a body of water 16. Although the non- restrictive, illustrative embodiments are described herein in relation to a wooden post, it should be kept in mind that the present invention applies to other types of wooden pieces as well. [0023] The wooden post 10 has a portion 14 that is immersed in water 16, below a water fine 22. Due to the presence in water 16 of marine microorganisms (not shown) such as Teredo, Bankia, Limnoria and Celuria, for example, the portion 14 of the wooden post 10 degrades relatively slowly. More specifically, the above-mentioned and/or other marine microorganisms attack the wood of the portion 14 and cause a loss of structural integrity of the wood. For example, a 35 to 40 cm (about 12 to 14 inches) diameter piece of "Querqus querqus" or similar equivalent American wood species such as Douglas Fir and Southern Pine, degrade in 1 to 4 years in the Carabean sea; in 2 to 5 years in the Meditarean sea; in 4 to 6 years in the Baltic sea or in the Atlantic ocean; and in 2 to 5 years in the Lagoon of Venice.
[0024] In order to mitigate the degradation of the portion 14 of the wooden post 10 immersed in water 16, a large number of staples such as 18 are driven into a water-exposed surface 20 of the wooden post 10. Each staple 18 is driven into the post 10 so that a portion of the staple 18 is exposed to the water 16 at the surface 20 of the wooden post 10. The distribution of the staples 18 on the water-exposed surface 20 of the wooden post 10 wili be described in more detail in the following description.
[0025] Turning now to Figure 2, a staple 18 will now be described.
The staple 18 comprises three integral elements: a first prong 24, a second prong 26, and a unking member 28. The linking member 28 has a first 32 and a second 34 opposite ends. The first 24 and second 26 prongs each have a proximal end 36 and a distal end 30.
[0026] The proximal end 36 of the first prong 24 is connected to the first end 32 of the linking member 28 while the proximal end 36 of the second prong 26 is connected to the second end 34 of the linking member 28. As shown in Figure 2, the first and second prongs 24 and 26 are substantially parallel to each other, and substantially perpendicular to the linking member 28. Typically, the distal ends 30 of the first and second prongs 24 and 26 are terminated by needle-like points 38 to facilitate penetration of the staple 18 into the wooden post 10. Figure 3 illustrates the staple 18 with its first and second prongs 24 and 26 driven into the wooden post 10, with the linking member 28 exposed at the surface 20 of the wooden post 10.
[0027] The staple 18 comprises iron (Fe) so that it oxides in contact with water to produce iron(ll) oxide (FeO), also known as ferrous oxide. Microorganisms present in the water 16 degrade the wood of the wooden post 10, for example by metabolizing an enzyme of the cellulose contained in the wood, in general, marine microorganisms cannot metabolize ferrous oxide. As the plurality of staples 18 driven into the water-exposed surface 20 of the wooden post 10 oxide, rings 44 of ferrous oxide are produced around the staples (Figures 4, 4A and 4B). Given sufficient time and provided that certain requirements (described herein below) are met relative to the length of the staples 18, more specifically the length of the prongs 24 and 26, and an homogeneous density of the staples 18 on the water-exposed surface 20, the rings 44 will expand to overlap each other so as to form a ferrous oxide protective barrier 40 on and underneath the water-exposed surface 20 over a certain thickness 42 into the wooden post 10. (Figure 3). In fact, the ferrous oxide is at least partially absorbed into the wooden fibers.
[0028] Advantageously, ferrous oxide is not toxic for human health or marine ecology in general. Accordingly, the ferrous oxide protective barrier 40 forms a non-toxic, ecologic defense for wooden material against marine microorganisms.
[0029] In order for the ferrous oxide protective barrier 40 to form efficiently on and underneath the water-exposed surface 20 of the wooden post 10, the length of the prongs 24 and 26 (and therefore the deepness of driving of the staples 18 in the wooden piece 10), and an homogeneous density of staples 18 driven through the water-exposed surface 20 of the wooden post 10 will advantageously meet the requirements indicated in the table below.
Post with a circular section
Post diameter staples shaft length Density of staples Duration
(cm) (mm) (staples/m 21 (years)
18 to 20 25 2 100 to 4200 5 to 12
20 to 24 30 2 100 to 4200 5 to 12
25 to 28 30 2 100 to 4200 5 to 12
28 to 30 35 2 100 to 4800 5 to 18
30 to 35 35 2 100 to 4800 5 to 18
35 to 38 40 4 800 to δ 000 18 to 30
38 to 40 45 4 800 to δ 000 18 to 30
40 to 45 or more 45 4 800 to 6 000 18 to 30
Post with a square section
Post side staples shaft length Density of staples Duration
(cm) (mm) (sfaρles/m 2 ' (years)
12 to 14 25 2 100 to 4 200 5 to 15
14 to 16 30 2 100 to 4800 5 to 15
16 to 18 35 2 100 to 4 800 5 to 15
18 to 20 40 4 800 to 6 000 18 to 30
20 to 24 45 4 600 to 6 000 18 to 30
26 to 30 45 4 800 to 6 000 18 to 30
32 to 36 50 4 800 to 6000 18 to 30
38 to 44 or more 50 4800 to 6 000 18 to 30
[0030] The above table indicates the durability of a wooden post having a portion thereof immersed in water as a function of the following factors:
- The cross sectional dimension(s) of the wooden post;
- The length of the prong(s) of the staples; and
- The density of staples by surface unit of the water-exposed surface of the wooden post. [0031] From the above table, it is noted that the length of the prongs of the staples and the density of staples increase with the cross sectional dimension(s) (diameter or side dimension) in accordance with a certain relation to produce an efficient ferrous oxide barrier 40 protecting the wood against marine microorganisms.
[0032] The quality of the wood forming the post constitutes another factor that can influence the durability of the wooden post.
[0033] In the illustrative, non-restrictive embodiment, the staples 18 are two-prong staples made, for example, of wire material comprising about 90% iron and having a diameter of about 1.53 mm.
[0034] Using the specifications given in the above table:
[0035] - About three (3) weeks are required for the rings 44 to form on the water-exposed surface of the wooden post 10; and
[0036] - About three (3) months to a year (depending on the wood species) are required for the ferrous oxide protective barrier 40 to form. Thickness 42 can reach a value as high as 10 cm.
[0037] A ferrous oxide protective barrier against the action of microorganisms according to the above described non restrictive, illustrative embodiments, can be expected to mitigate degradation of a wooden piece immersed in water for a period of time as long as thirty (30) years, as indicated in the above table.
[0038] For example, as indicated by the above table, a wooden post with circular section having a diameter between 35 and 45 cm and a water- exposed surface in which are driven staples with prongs having a length between 40 and 45 mm and with a density of 4800 to 6000 staples per square meter will result in a durability of the wooden post between 18 to 30 years. This demonstrates the efficiency of the method according to the present invention.
[0039] Of course, the staples 18 will be advantageously, regularly distributed over the water-exposed surface 20 of the wooden post 10 to form an homogeneous density of staple and therefore produce an homogeneous ferrous oxide protective barrier 40,
[0040] As illustrated in Figures 1 , 4, 5, 6, 7, 8 and 9, the staples 18 can be driven into the water-exposed surface 20 of the wooden post 10 with their linking members 28 exposed at the surface 29 and extending generally horizontally. As illustrated in Figures 1A, 4A, 5A, 6A 1 7A, 8A and 9A 1 the staples 18 can be driven into the water-exposed surface 20 of the wooden post 10 with their linking members 28 exposed at the surface 20 and extending generally vertically. As illustrated in Figures 1B, 4B, 5B, 6B, 7B, 8B and 9B, the staples 18 can be driven into the water-exposed surface 20 of the wooden post 10 with their linking members 28 exposed at the surface 20 and extending at an inclination with respect to the horizontal. Any orientation of the linking members 28 of the staples 18 on the water-exposed surface 20 of the wooden post 10 will not substantially affect the operation of the method.
[0041] Figures 5, 5A and 5B schematically illustrate a first example of distribution of staples on the water-exposed surface of a wooden post having a diameter of 250 mm. The length of the prongs of the staples ranges from about 30 to about 40 mm. The staples are distributed using the following orthogonal spacing values (X, XA, Z) and (Y, YA, L) to form a regular staggered pattern:
X = 23.3 mm XA = 15.5 mm Z = 23.3 mm Y = 15.5 mm YA = 23.3 mm L = 15.5 mm
[0042] Figures 6, 6A and 6B schematically illustrate a second example of distribution of staples on the water-exposed surface of a wooden post used for supporting a dock and having a diameter ranging from about 250 to about 300 mm. The length of the prongs of the staples ranges from about 30 to about 40 mm. The staples are distributed using the following orthogonal spacing values (X, XA, Z) and (Y, YA, L) to form a regular staggered pattern:
X = 14.2 mm XA = 5.7 mm Z = 14.2 mm
Y = 5.7 mm YA = 14.2 mm L = 5.7 mm
[0043] Figures 7, 7A and 7B schematically illustrate a third example of distribution of staples on the water-exposed surface of a wooden post used for supporting a signal and having a diameter ranging from about 350 to about 400 mm. The length of the prongs of the staples is about 40 mm long. The staples are distributed using the following orthogonal spacing values (X, XA 1 Z) and (Y, YA, L) to form a regular staggered pattern:
X = 12.5 mm XA = 5.7 mm Z = 12.5 mm
Y = 5.7 mm YA = 12.5 mm L = 5.7 mm
[0044] Figures 8, 8A and 8B schematically illustrate a fourth example of distribution of staples on the water-exposed surface of a wooden post used for supporting a signal and having a diameter ranging from about 350 to about 400 mm. The length of the prongs of the staples is about 40 mm long. The staples are distributed using the following orthogonal spacing values (X, XA, Z) and (Y, YA, L) to form to form a regular staggered pattern: X = 11.1 mm XA = 5.7 mm Z = 11.1 mm
Y = 5.7 mm YA = 11.1 mm L = 5.7 mm
[0045] Figures 9, 9A and 9B schematically illustrate a fifth example of distribution of staples on the water-exposed surface of a wooden post used for supporting a signal and having a diameter ranging from about 350 to about 400 mm. The length of the prongs of the staples is about 40 mm long. The staples are distributed using the following orthogonal spacing values (X, XA, Z) and (Y 1 YA, L) to form a regular rectangular pattern:
X = 10 mm XA = 5.7 mm Z = 10 mm
Y = 5.7 mm YA = 10 mm L = 5.7 mm
[0046] The above described non-restrictive, illustrative embodiments can be modified at will, within the scope of the appended claims, without departing from the spirit and nature of the subject invention. For example, it is possible to consider the use of staples of various dimensions and iron contents, including staples comprising only one prong. Sn the latter case, the density of staples and/or the diameter of the wire material will be adapted accordingly.