CA2889590A1

CA2889590A1 - Protective screen and visor produced therewith for a safety helmet, particularly a forestry worker's helmet

Info

Publication number: CA2889590A1
Application number: CA2889590A
Authority: CA
Inventors: Anton Pfanner; Martin Greber
Original assignee: Pfanner Schutzbekleidung GmbH
Current assignee: Pfanner Schutzbekleidung GmbH
Priority date: 2012-10-26
Filing date: 2013-10-16
Publication date: 2014-05-01
Anticipated expiration: 2033-10-16
Also published as: DE102012021587B4; NZ707340A; WO2014063969A1; US20150272259A1; EP2911540B1; DE102012021587A1; AU2013336891A1; EP2911540A1; AU2013336891B2; CA2889590C

Abstract

A protective screen (10) to protect the face and, above all, the eyes of a person against flying particles and sharp objects has a mesh (12) with a mesh structure which is formed from a plurality of adjacent rows of hexagonal openings (14), which rows are bounded by mesh webs (16) common to the openings (14). The openings (14) in the mesh (12) are each of substantially the same area. The mesh (12) is enclosed by an edge (18) with no mesh structure which has a width (B) which is at least equal to the height (H) of a row of openings (14) in the mesh structure. The mesh webs (16) of at least two rows of openings (14) adjacent to the edge (18) can be made thicker than the mesh webs for the other openings, wherein, however, all the openings in the mesh (12) are nevertheless substantially identical in area. The mesh (12) is produced by etching spring steel sheet. A visor for a safety helmet, especially a forestry worker's helmet is produced from the protective screen (10) by injection moulding a supporting frame around its edge (18).

Description

Protective screen and visor produced therewith for a safety helmet, particularly a forestry worker's helmet The invention relates to a protective screen for the face and above all the eyes of a per-son, against flying particles and pointed objects, in particular during forestry work, having a mesh with a mesh structure which is formed by a multiplicity of mutually adjacent rows of noncircular openings which are delimited by mesh webs which are common to the open-ings.
A protective face screen of this type is known from document EP 1 182 943 B1.
The for-mer is manufactured by etching metal, and comprises a mesh which forms a large number of light-permeable openings, the openings containing various surfaces. The protective screen has at least two regions. The surface of each opening within each region is identi-cal and the surfaces of the openings in different regions differ. The mesh is enclosed by a continuous rim, the width of which corresponds to about the thickness of one of the mesh webs between adjacent openings of the mesh. Such a rim cannot be expected to substan-tially contribute toward the stability of the mesh. Once the protective screen is insertion-molded with a support frame of plastic which encloses the mesh, irregular transitions be-tween the inner boundary of the support frame and the mesh moreover arise, because the plastic spreads in an irregular manner into some openings of the mesh and not into other openings. Furthermore, the mesh of the known protective face screen in the various re-gions has in each case different stability and strength, because the latter are determined on the one hand by the size of the openings of the mesh, which differs in the various re-gions, and on the other hand by the thickness of the mesh webs, which likewise differs in the various regions. The size of the surfaces which differs from region to region also brings about that the mesh also has a degree of light transmission which differs from region to region.
Document FR-A-826 990 discloses a screen for protecting the human eye from excessive sunlight, which replaces the usual colored lenses in sunglasses. The screen is composed

- 2 -of a circular plate which is adapted so as to be insertable into the lens opening of a spec-tacle frame. The screen comprises a multiplicity of mutually adjacent rows of round, that is to say circular, openings of the same diameter, or rows of circular openings having two different diameters. There should be no problems in respect of stability and quality of ap-pearance in the case of the known screen, since the screen overall has only a diameter which in the initial state of the screen is not much larger than the lens opening of a specta-cle frame in which said screen is gripped on its entire circumference.
Protective screens such as employed in a visor of a protective helmet are many times larger and thus not comparable to a protective screen of the size of a spectacle lens, at least not in terms of stability.
It is an object of the invention to improve stability in a mesh of the type mentioned at the outset, and to improve the quality of appearance of a support frame which is molded to the mesh. Moreover, a visor for a protective helmet, particularly a forestry worker's helmet, is to be provided.
Proceeding from a support frame of the type mentioned at the outset, this object is achieved according to the invention in that the openings, apart from part-openings which immediately adjoin a rim of the mesh which is without a mesh structure, in each case have a substantially identical surface area, wherein the rim encloses the mesh and along its circumference has a width which is at least equal to a height of a row of openings of the mesh structure. The large width of the rim of the protective screen according to the inven-tion substantially contributes toward increasing stability of the mesh. The same surface areas of the openings of the mesh impart to the latter a degree of light transmission which is substantially homogenous in the region of the entire mesh. The wide rim moreover ena-bles the protective screen according to the invention to be provided with a support frame having a uniformly running inner boundary.
A visor for a protective helmet, particularly a forestry worker's helmet, which is manufac-tured from a protective screen according to the invention, the rim of which is insertion-molded with a support frame of plastic, has the desired increased stability and the targeted improved appearance.
Advantageous design embodiments of the protective screen and of the visor according to the invention form the subject matter of the dependent claims.

- 3 -In one design embodiment of the protective screen according to the invention the width of the rim is at least equal to the height of two vertically adjacent rows of openings of the mesh structure. Based on the minimum width of the rim which is used in this design em-bodiment, this configuration imparts to the protective screen and to the visor according to the invention the targeted greater stability.
In one further design embodiment of the protective screen according to the invention the rim is provided with clearance holes which are distributed across its length and which pre-dominantly are each smaller than each of the mesh openings. These clearance holes are a few clearance holes of a comparatively large diameter which as fitting holes facilitate insertion of the protective screen into a processing machine in which the protective screen in its entirety is coated with a protective layer, or in which the protective screen is inser-tion-molded with a support frame, and are substantially more clearance holes of compara-tively small diameter through which the plastic can pass during the manufacture of the support frame in order to improve the connection between the mesh and the support frame.
In a further design embodiment of the protective screen according to the invention the min-imum number of openings in the mesh per square centimeter is at least 15. The number of openings per square centimeter here is selected according to the protection requirements.
For example, if it is known that shavings of softwood arise during forestry work, a coarser mesh may be selected. However, a finer mesh should be selected where shavings of hardwood arise. In the present context, coarse means, for example, 16 openings/cm2, in contrast thereto fine means, for example, 39 openings/cm2.
In a further design embodiment of the protective screen according to the invention the thickness of the mesh webs is selected so as to be inversely proportional to the number of openings per square centimeter. Thus, in the case of the selected coarse mesh having 16 openings/cm2 the thickness of the mesh webs may be approx. 0.3 mm, in contrast thereto in the case of the fine mesh having 39 openings/cm2 approx. 0.2 mm. The associated height of one row of openings of the mesh structure in the two aforementioned examples may be approx. 3 mm or approx. 2 mm, respectively, wherein this value would then also be the minimum width according to the invention of one row of openings of the mesh struc-ture.

- 4 -In a further design embodiment of the protective screen according to the invention the mesh webs, that in a zone the width of which is at least equal to the vertical height of one of the rows and that is adjacent to the rim on its circumference, the mesh webs are config-ured to be thicker than the mesh webs of the remaining openings. On account thereof, a further increase in the already high and adequate stability per se of the protective screen according to the invention may be achieved.
In a further design embodiment of the protective screen according to the invention the width of the zone is substantially equal to the height of two vertically adjacent rows of openings of the mesh structure. In comparison to the overall mesh, the zone thus has a modest width which, however, on account of the mesh webs which are configured so as to be thicker within the zone, still substantially increases the strength and stability of the mesh. The degree of transmission within the zone is substantially equal to the degree of transmission of the mesh outside the zone, since the surface areas of the openings which are surrounded by comparatively thick webs are substantially equal to those of the open-ings which are surrounded by comparatively thin mesh webs.
In a further design embodiment of the protective screen according to the invention the openings in the zone have the same vertical center spacing as the openings in the remain-ing mesh. The achieved additional rigidity of the mesh does not compromise the degree of light transmission, in particular not in the so-called viewing opening, since the zone lies at the rim of the mesh, and moreover since all openings of the mesh which are outside and within the zone are disposed in the same grid pattern.
In a further design embodiment of the protective screen according to the invention the mesh is manufactured from spring steel sheet. In this case, a thin metal sheet may be em-ployed in order to achieve the desired stability at the lowest weight of the protective screen and, in particular, to ensure protection against high-velocity particles.
In a further design embodiment according to the invention the mesh is manufactured by etching. Etching is the preferred manufacturing method when metal is employed for the mesh of the protective screen. Protective face screens may indeed also be manufactured from a woven metal wire or plastic mesh, but such meshes have various disadvantages for the carrier which etched metal meshes do not have. Such disadvantages include, for ex-ample, that the wires occupy a large part of the entire surface of the mesh and result in lower stability and mechanical strength than an etched metal mesh. Moreover, such wo-

- 5 -ven wire or plastic meshes may be pierced by pointed objects, such as pointed branches or twigs, because wires or plastic threads are displaceable in relation to one another.
In one design embodiment of the visor according to the invention an inner boundary of the support frame which faces the mesh has a spacing from an inner circumference of the rim which adjoins the mesh. On account thereof, a clean appearance of the inner boundary of the support frame is ensured in a simple manner.
Exemplary embodiments of the invention are described in more detail in the following with reference to the drawings, in which:
Fig. 1 shows a plan view of a first exemplary embodiment of a protective screen according to the invention, having a mesh of spring steel sheet;
Fig. la shows a detail of the protective screen according to fig. 1 in a larger scale;
Fig. 2 shows a second exemplary embodiment of the protective screen according to the invention, having a mesh of spring steel sheet which has a finer mesh structure than the mesh of the first exemplary embodiment;
Fig. 2a shows a detail of the protective screen according to fig. 2 in a larger scale;
Fig. 3 shows a third exemplary embodiment of the protective screen according to the invention, which corresponds to the first exemplary embodiment but has a different mesh structure in the peripheral region;
Fig. 3a shows as a detail the peripheral region of the protective screen according to fig. 3 in a larger scale;
Fig. 4 shows a fourth exemplary embodiment of the protective screen according to the invention, which corresponds to the second exemplary embodiment but in a zone which is adjacent to the rim has a different mesh structure; and Fig. 4a shows as a detail the zone and an adjacent region of the protective screen according to fig. 4 in a larger scale.

- 6 -Fig. 1 shows a plan view of a first exemplary embodiment of a protective screen according to the invention, which in its entirety is referred to as 10, having a mesh 12 of a thin spring steel sheet.
Fig. la shows a detail of the protective screen 10 according to fig. 1 in a larger scale. The mesh 12 has a mesh structure which is formed from a multiplicity of mutually adjacent rows of noncircular openings 14. According to the illustration in fig. la, the openings are in each case hexagonal and delimited by common mesh webs 16 which have a thickness D.
Apart from part-openings 13 which immediately adjoin an encircling rim 18, which is with-out a mesh structure, but which are negligible in the overall scheme, the openings 14 of the mesh 12 have in each case identical surface areas. Furthermore, on account of this construction, in each case two adjacent rows of openings 14 of the mesh have one and the same vertical center spacing M.
The mesh 12 is enclosed by the rim 18 which has a width B which is at leas' t equal to a height H of one row of openings 14 of the mesh structure. Preferably, the width of the rim 10 is at least equal to the height of two vertically adjacent rows of openings 14 of the mesh structure.
The rim 18 is provided with clearance holes 15, 17 which are distributed across its length and which predominantly are each much smaller than each of the openings 14 of the mesh 12. In the case of the first exemplary embodiment of the protective screen 10 which is illustrated in figs. 1 and la, these clearance holes are clearance holes 15 of a compara-tively large diameter and predominantly clearance holes 17 of a comparatively small di-ameter. Each clearance hole 15 substantially has a surface area which is identical to one of the openings 14 of the mesh structure. The clearance holes 15 of a comparatively large diameter are fitting holes which facilitate the insertion of the protective screen 10 into a processing machine in which the protective screen in its entirety is coated with a protective coating and/or in which the protective screen is insertion-molded with a support frame (not illustrated). The clearance holes 17 of a comparatively small diameter, of which there are substantially more than of the clearance holes 15 of a comparatively large diameter, ena-ble the plastic to pass through during molding of a support frame 52 which is indicated in fig. 4, in order to improve the connection between the mesh 12 and the support frame 52.
Fig. 2 shows a second exemplary embodiment of a protective screen according to the in-vention, which in its entirety is referred to as 20, having a mesh 22 of spring steel sheet

- 7 -which has openings 24 which are smaller than the openings 14, and has a finer mesh structure than the mesh 12 of the first exemplary embodiment. The minimum number of openings 14, 24 per square centimeter in the mesh 12 or 22, respectively, is at least 15, according to DIN EN 1731. The actually used number of openings in the mesh is selected according to the protective requirements, that is to say according to whether, for example, protection against flying particles which are softwood shavings or hardwood shavings is to be ensured. The mesh 22 has mesh webs 26 which have a thickness D which is inversely proportional to the number of openings per square centimeter. In the first exemplary em-bodiment of the protective screen according to the invention the mesh 12 is a compare-tively coarse mesh having sixteen openings 14 per square centimeter. In the second ex-emplary embodiment of the protective screen 20 according to the invention the mesh 22 is a comparatively fine mesh having thirty-nine openings 24 per square centimeter. The de-tails which are shown in figs. la and 2 make it apparent that the thickness D
of the mesh webs 16 in the comparatively coarse mesh 12 is greater than the thickness D in the com-paratively fine mesh 22. The details in figs. la and 2a are illustrated on the same scale of enlargement, such that it is immediately obvious that the comparatively coarse mesh 22 has substantially fewer rows and openings 14 than the comparatively fine mesh 22 has rows of openings 24. The openings 24 of the mesh 22 all have identical surface areas.
The same applies to the openings 14 of the mesh 12, wherein however the mesh 22, hay-ing an identical surface area to that of the mesh 12, has substantially more openings 24 than the mesh 12 has openings 14.
Fig. 3 shows a third exemplary embodiment of the protective screen according to the in-vention, which in its entirety is referred to as 30 and which corresponds to the protective screen 10 according to the first exemplary embodiment, but has a different mesh structure in the peripheral region. As a detail, fig. 3a shows the peripheral region of the protective screen 30 according to fig. 3 on a larger scale. Same parts as in figs. 1 and 2 are provided with the same reference signs in figs. 3 and 4 and do not require renewed description.
In the exemplary embodiments according to figs. 3 and 4, mesh webs 36a and 46a, re-spectively, of openings 34a and 44a, respectively, which lie in a zone 70 (shown in fig.
having a dashed delimitation) adjacent to the rim 38 and 48, respectively, have a larger thickness D than mesh webs 36b and 46b, respectively, of the remaining openings 34 and 44, respectively. Here, openings 34 and 34a or 44 and 44a, respectively, in adjacent rows outside or within the zone 70, respectively, have the same vertical center spacing M as the openings in the remaining adjacent rows of the mesh 32 and 42, respectively.

- 8 -The zone 70 has a width BZ which is at least equal to the vertical height H of one of the rows. In the exemplary embodiments according to figs. 3 and 4 the width BZ of the zone 70 substantially is equal to the height of two vertically adjacent rows of openings 34 or 44, respectively, of the mesh structure. For improved clarity of the openings 44a which lie within the zone 70, their areas are marked with dots in fig. 4a. The comparatively thick webs of the openings 44a are achieved by way of a somewhat modified hexagonal shape within the openings 44a in relation to the hexagonal shape within the openings 44. In the corners of the hexagon of the openings 44a, said corners are configured so as to be rounded, in contrast to the corners of the hexagon of the openings 44, which have no cur-vature radius. In this way, thicker webs 46a of the openings 44a than the webs 46b of the openings 44 are achieved while maintaining the grid pattern, specifically while maintaining a substantially identical surface area of the openings 44a and 44.
The protective screens 10, 20, and 30, like the protective screen 40, may be provided with a zone 70 in which the mesh webs are configured so as to be thicker than in the remaining part of the mesh 12, 22, and 32, respectively.
In all exemplary embodiments which are described above and illustrated in the drawings the mesh 12, 22, 32, and 42, respectively, is manufactured from spring steel sheet, specif-ically by etching. According to a photolithographic process or similar, the mesh structure is applied onto the metal sheet, using a protective lacquer. The mesh is etched from all points which are not covered by the lacquer, in order to manufacture in this manner the desired mesh structure having the wide rim 18, 28, 38, and 48, respectively, which enclos-es the mesh structure.
The protective screen 10, 20, 30, and 40, respectively, is insertion-molded with a support frame of plastic, and is thus employable as a visor for a protective helmet, particularly a forestry worker's helmet. Here, according to the illustration indicated in fig. 4, an inner boundary 50 of an indicated support frame 52, which faces the mesh 42, has a spacing A
from an inner circumference 54 of the rim 48, which adjoins the mesh 42. On account thereof, the support frame 52 has no contact with the actual mesh 42 and, after manufac-turing, has a uniform inner delimitation.

- 9 -List of reference signs

10 Protective screen 12 Mesh 13 Part-opening 14 Opening Clearance hole 10 16 Mesh web 17 Clearance hole 18 Rim Protective screen 22 Mesh 15 23 Part-opening 24 Opening 26 Mesh web 28 = Rim Protective screen 20 32 Mesh 33 Part-opening 34a Opening 36a Mesh web 36b Mesh web 25 38 Rim Protective screen 42 Mesh 43 Part-opening 44 Opening 30 44a Opening 46a Mesh web 46b Mesh web 48 Rim Boundary 35 52 Support frame 54 Inner circumference A Spacing B Width D Web thickness H Height M Center spacing BZ Zone width

Claims

claims

1. A protective screen for the face and above all the eyes of a person, against flying particles and pointed objects, in particular during forestry work, having a mesh (12, 22, 32, 42) with a mesh structure which is formed by a multi-plicity of mutually adjacent rows of noncircular openings (14, 24, 34, 44) which are delimited by mesh webs (16, 26, 36a, 36b, 46a, 46b) which are common to the openings, characterized in that the openings (14, 24, 34, 44, 54), apart from part-openings (13, 23, 33, 43) which immediately adjoin a rim (18, 28, 38, 48) of the mesh (12, 22, 32, 42) which is without a mesh structure, in each case have a substantially identical surface area, wherein the rim (18, 28, 38, 48) encloses the mesh (12, 22, 32, 42) and along its circumference has a width (B) which is at least equal to a height (H) of a row of openings (14, 24, 34, 44) of the mesh structure.

2. The protective screen as claimed in claim 1, characterized in that the width (B) of the rim (18, 28, 38, 48) along its circumference is at least equal to the height (H) of two vertically adjacent rows of openings (14, 24, 34, 44) of the mesh structure.

3. The protective screen as claimed in claim 1 or 2, characterized in that the rim (18, 28, 38, 48) is provided with clearance holes (15, 17) which are distributed across its length and which predominantly are each smaller than the mesh openings (14, 24, 34a, 34b, 44a, 44b).

4. The protective screen as claimed in one of the preceding claims, characterized in that the minimum number of openings (14, 24, 34a, 34b, 44a, 44b) in the mesh (12, 22, 32, 42) per square centimeter is at least 15.

5. The protective screen as claimed in one of the preceding claims, characterized in that in a zone (70) the width of which is at least equal to the vertical height (H) of one of the rows and that is adjacent to the rim (38, 48) on its circumference, the mesh webs (36a, 46a) are configured to be thicker than the mesh webs (36b, 46b) of the remaining openings (34, 44).

6. The protective screen as claimed in claim 5, characterized in that the width (BZ) of the zone (70) is substantially equal to the height (H) of two vertically adjacent rows of openings (14, 24, 34, 44) of the mesh structure.

7. The protective screen as claimed in claim 5 or 6, characterized in that the openings (34a, 44a) in the zone (70) have the same vertical center spacing (M) as the open-ings (34, 44) in the remaining mesh (32, 42).

8. The protective screen as claimed in one of the preceding claims, characterized in that the mesh (12, 22, 32, 42) is manufactured from spring steel sheet.

9. The protective screen as claimed in claim 8, characterized in that the mesh (12, 22, 32, 42) is manufactured by etching.

10. A visor for a protective helmet, particularly a forestry worker's helmet, manufac-tured from a protective screen (10, 20, 30, 40) as claimed in one of the preceding claims, the rim (18, 28, 38, 48) thereof being insertion-molded with a support frame (52) of plastic.