ATBECHDEDKESFRGBGRITLILUNLSEMCPTIESILTLVFIROMKCYALTRBGCZEEHUPLSKBAHRIS..MTNORSMESMMAKHTNMD..........
J
BDM Ver 2.0.15 (20th of December) - 1100000/0
3988735
EUROPEAN PATENT APPLICATION
A1
20220427
EP
20203697.6
20201023
en
en
en
20220427
202217
20220427
202217
E04C 2/08 20060101AFI20210409BHEP
E04B 9/064 20130101 LA20210406BHEP
E04B 9/20 20130101 LA20210406BHEP
E04B 9/06 20130101 LI20210412BHEP
de
SCHIENE ZUR BEFESTIGUNG EINES HÄNGEDECKENSYSTEMS AN EINER BETONDECKE
en
A RAIL FOR ATTACHING A SUSPENDED CEILING SYSTEM TO A CONCRETE CEILING
fr
RAIL PERMETTANT DE FIXER UN SYSTÈME DE PLAFOND SUSPENDU À UN PLAFOND EN BÉTON
8
Illinois Tool Works INC.
101761714
P306425EP
155 Harlem Avenue
Glenview, IL 60025
US
PERRIER, Matthieu
Illinois, 60025
US
SIMONIN, Jean-Luc
Illinois, 60025
US
BONNEFOY, Florence
Illinois, 60025
US
HGF
101859891
HGF Limited 1 City Walk
Leeds LS11 9DX
GB
AL
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MC
MK
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NL
NO
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TR
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ME
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TN
The present invention provides a rail (1) for attaching a suspended ceiling system (18) to a concrete ceiling (16). The rail (1) comprises a nailing region (2a, 2b) that is attachable to the concrete ceiling (16) by a plurality of nails (17). The rail (1) also has an attachment feature (8) for attachment of a part (19) of the suspended ceiling system (18) to the rail (1).
The present invention relates to a rail for attaching a suspended ceiling system to a concrete ceiling. In particular, the invention relates to a rail that can be nailed to a concrete ceiling and that includes an attachment feature for attachment to a part of the suspended ceiling system.

BACKGROUND
A suspended ceiling, otherwise known as a dropped ceiling or false ceiling, is formed of rails that are suspended from a ceiling and that support ceiling panels.
When installed on a concrete ceiling, in particular a planar concrete ceiling, the suspended ceiling is attached to the concrete using anchors that are secured to the ceiling. The anchors are installed by the following process:
1. i. marking fastening positions in a grid of about 60cm squares
2. ii. drilling holes in the marked positions
3. iii. hammering anchors into the drilled holes
4. iv. expanding the anchors to secure them to the drilled holes using a tool
The anchors include either a female threaded connector or a hook. Once the anchors are installed either threaded rods are screwed in the female threaded connector, or a suspension wire is hooked onto the hook. A frame is attached to the threaded rods or suspension wires, and the panels are supported on the frame.
The process of installing anchors requires accurately laying out the grid of fastening positions, which is time consuming and prone to inaccuracy. Moreover, to mark the fastening positions, drill the holes, hammer in the anchors, and expand the anchors the installer must be raised to have access to ceiling. This requires a ladder or platform that must be moved around the room, making the process lengthy. Drilling upwards into the ceiling is also inconvenient and may cause health and safety issues.

BRIEF SUMMARY OF THE DISCLOSURE
The present invention provides a rail for attaching a suspended ceiling system to a concrete ceiling, the rail comprising:
a nailing region that is attachable to the concrete ceiling by a plurality of nails, and an attachment feature for attachment of a part of the suspended ceiling system to the rail.
In examples, the attachment feature comprises a thread for attachment of a threaded part of the suspended ceiling system. For example, the rail may comprise a threaded hole for attachment of a threaded part of the suspended ceiling system.
In examples, the attachment feature comprises a nut, the nut comprising the thread.
In examples, the rail further comprises a recessed region arranged such that when the rail is nailed to the concrete ceiling the recessed region defines a cavity between the rail and the concrete ceiling. The nut may be positioned in the recessed region, and the rail may further comprise an opening corresponding with the nut. The opening may be a circular or oval hole, or an elongate slot. Accordingly, a threaded rod of the suspended ceiling system can pass through the opening and engage the nut.
The recessed region may include one or more retaining members to restrain the position of the nut in the recessed region. The retaining members may trap the nut in the recessed region. The retaining members may comprise tabs. The tabs may be attached to the rail, for example welded or adhered to the rail, or they may be punched and folded from the rail to extend into the recessed region.
The recessed region may be elongate and the nut may be slidable along the recessed cavity in a lengthways direction of the rail. The opening may be an elongate slot to accommodate different positions of the nut within the recessed region.
In examples, the recessed region is formed along the length of the rail. In examples, the rail is elongate and has a uniform profile. The recessed region may extend through the entire length of the rail.
In examples, the nut is attached to the rail. For example, the nut may be welded to the rail. In other examples, the nut may be adhered to the rail.
In examples, the rail may comprise a boss extending from the rail, and the boss may comprise the thread for attachment of a threaded part of the suspended ceiling. The boss may be punched from the material of the rail, or it may be attached to the rail, for example by welding or adhering, or the boss may be attached to the rail by an interference fitting between the boss and a hole in the rail.
In examples, the attachment feature may comprise an opening for attachment of a hooked wire of the suspended ceiling system. The opening may comprise a circular or oval hole, or an elongate slot. In examples, the rail may comprise a recessed region arranged to define a cavity between the rail and the concrete ceiling when the rail is nailed to the concrete ceiling. The opening may be formed in the recessed region. The recessed region provides space to accommodate the hook of the hooked wire.
The rail may comprise a plurality of attachment features spaced along the length of the rail. Accordingly, the suspended ceiling system can be attached to the rail at a plurality of points, for supporting the frame of the suspended ceiling system.
In examples, the rail comprises a generally 'U' shaped profile having a central portion comprising the nailing region, and opposing side wings. The opposing side wings may be diverging from the central portion to permit stacking of multiple rails.
In examples, the rail is manufactured by a folding process or an extrusion process. The rail may have a uniform profile along its length.
In examples, the central portion of the rail comprises a recessed region arranged to define a cavity between the rail and the concrete ceiling when the rail is nailed to the concrete ceiling. The recessed region may be formed by folds or bends in the rail, in particular in the central portion. With a recessed region, the rail may have a generally 'M' shaped profile.
In examples, the attachment feature is arranged in the recessed region. For example, as described above, a thread (e.g., a threaded hole, a nut, an internally threaded boss, or an opening for a hook) may be disposed in the recessed region of the rail, and/or the recessed region of the rail may comprise an opening for attachment of a hooked wire of the suspended ceiling system.
In examples, the nailing region comprises first and second nailing regions extending along opposite sides of the recessed region. The first and second nailing regions may be continuous regions extending along the length of the rail. Alternatively, each of the first and second nailing regions may comprise separate regions spaced along the rail.
In examples, the nailing region or nailing regions may be marked on the rail along the length of the rail. The marks may indicate to an installer where to nail the rail to the concrete ceiling.
In examples, the rail comprises a sheet material, for example a metal sheet material, in particular a sheet steel material. The sheet steel material may be folded to form the rail.
In examples where the rail comprises a sheet steel material, the nailing region comprises a maximum thickness of 3 millimeters. In examples, the rail is manufactured from a sheet steel material having a maximum thickness of 3 millimeters. In examples, the rail 1 may be manufactured from a sheet steel material having a thickness of between 0.6 millimeters and 3 millimeters, for example 1 millimeter, 2 millimeters, 2.5 millimeters, or 3 millimeters.
In examples, the rail further comprises one or more ancillary attachment features for attaching ancillary components, such as cables or pipes. For example, the rail may comprise a hole or threaded hole for fastening a cable tie or clip to the rail, for attaching electrical cabling or the like to the rail. In other examples, the rail may comprise one or more clips for attaching electrical cabling or the like to the rail.
The rail can be installed on the concrete ceiling by nailing the rail through the nailing region into the concrete ceiling. A specialised nailing gun may be used, for example the Pulsa™ range of nail guns produced by SPIT PASLODE™. Nails may be used at closely spaced locations along the rail to provide secure attachment, for example every 5 centimetres, although the installer can provide nails at any location along the nailing region(s). The rail can therefore be installed on the concrete ceiling without the need for pre-installing anchors because the nails are driven through the rail and directly into the concrete ceiling. This also obviates the need for measurement and marking of fastening positions, because the nails can be driven into the concrete ceiling at any location along the length of the rail. Accordingly, the rail disclosed herein provides numerous advantages over known systems for attaching rails to concrete ceilings, that requires fewer parts and fewer operations to install.

BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
- FIG. 1 shows a perspective view of a rail for attaching a suspended ceiling system to a concrete ceiling;
- FIG. 2 shows a cross-section of the rail of FIG. 1, including a nut;
- FIG. 3 shows a cross-section of an alternative example rail having a welded nut;
- FIG. 4 shows a cross-section of an alternative example rail having a threaded hole;
- FIG. 5 shows a cross-section of an alternative example rail having a boss;
- FIG. 6 shows a cross-section of an alternative example rail having an alternative profile and a boss;
- FIG. 8 shows a cross-section of an alternative example rail having an alternative profile a boss attached by interference fit or welding;
- FIG. 8 shows an exploded assembly view of the rail and a part of a suspended ceiling system installed on a concrete ceiling;
- FIGS. 9A shows an alternative example rail having openings for attachment of a hooked suspension wire;
- FIG. 9B shows a hooked suspension wire for attaching to the openings of the rail of FIG. 9A;
- FIG. 10 shows multiple rails in a stacked arrangement;
- FIG. 11 shows an example rail including ancillary attachment features; and
- FIG. 12 shows an example rail that includes pre-installed ancillary features, in particular a cable.

DETAILED DESCRIPTION
FIGS. 1 and 2 show a rail 1 for attaching a suspended ceiling system to a concrete ceiling. The rail 1 has a nailing region 2 that is attachable to the concrete ceiling by a plurality of nails. The rail 1 also has an attachment feature 3 for attachment of a part of the suspended ceiling system to the rail 1.
As shown, in this example the rail 1 is elongate and comprises a uniform generally 'U' shaped profile having a central portion 4 and opposing side wings 5a, 5b that extend from opposing sides of the central portion 4. The rail 1 is made from a sheet material, for example a sheet steel material, and is folded or bent to form the profile. In alternative examples, the rail 1 may be extruded to form the elongate profile.
The nailing region 2 of the rail 1 of FIGS. 1 and 2 comprises first and second nailing regions 2a, 2b. The first and second nailing regions 2a, 2b extend along the rail 1 in the elongate direction. The first and second nailing regions 2a, 2b comprise planar faces that are positionable against a concrete ceiling, and which through nails can be driven to secure the rail to the concrete ceiling at the first and second nailing regions 2a, 2b. When the rail 1 is nailed to the concrete ceiling the opposing side wings 5a, 5b extend away from the concrete ceiling.
In this example, a recessed region 6 is provided in the central portion 4, between the first and second nailing regions 2a, 2b. The recessed portion 6 comprises a recess 7 that forms a cavity when the rail 1 is nailed to the concrete ceiling, as explained further hereinafter. The recessed portion 6 creates a generally 'M' shaped profile of the rail 1.
As shown in FIG. 2, a nut 8 is provided in the recess 7 formed by the recessed portion 6. The nut 8 would be located in the cavity between the rail 1 and the concrete ceiling when the rail 1 is nailed to the concrete ceiling.
In some examples, the nut 8 is movable along the recess 7 defined by the recessed portion 6. Accordingly, when the rail 1 is nailed to the concrete ceiling the nut 8 is able to be slid along the rail 1, in particular along the recessed portion 6, to change its position. In some examples, the nut 8, or a plurality of nuts 8, may be inserted into the recess 7 after the rail 1 is nailed to the concrete ceiling. In other examples, the rail 1, in particular the recessed portion 6, may include retaining parts to limit movement of the nut 8 along the rail 1. In such examples, the nut 8, or nuts 8, are positioned in the recess 7 before nailing the rail 1 to the concrete ceiling.
As shown in FIG. 1, the rail 1, in particular the recessed portion 6, includes an opening 9. The opening 9 corresponds to the position of the nut 8 such that a part of the suspended ceiling system can be attached to the nut 8 through the opening 9, as described further hereinafter.
As shown in FIG. 1, the opening 9 is an elongate slot. The elongate slot 9 can accommodate different positions of the nut 8 along the rail 1. In alternative examples, for example where the position of the nut 8 is limited or fixed, the opening 9 may comprise a circular or oval hole.
The rail 1 of FIGS. 1 and 2 provides for attaching a male threaded part of a suspended ceiling system to a concrete ceiling. As described above and described with reference to FIG. 8, the rail 1 is nailed to the concrete ceiling 16 and then a male threaded part, for example a threaded rod 19, of the suspended ceiling system 18 is attached to the nut 8 through the opening 9. A supporting frame 20 and panels 21 are then mounted on the threaded rod 19. A plurality of nuts 8 are spaced along the rail 1 to provide spaced attachment points for the suspended ceiling system 18. A series of parallel and/or perpendicular rails 1 nailed to the concrete ceiling 16 provides a grid of attachment points for the suspended ceiling system 18.
FIGS. 3 to 7 provide alternative example rails 1 that can be nailed to a concrete ceiling, as per the example of FIGS. 1 and 2.
In the examples of FIGS. 3 to 5 the rail 1 has a similar profile to the rail 1 of FIGS. 1 and 2, in particular an 'M' shaped profile having a central portion 4 with a recessed portion 6, and opposing side wings 5a, 5b extending from the central portion 4.
In the example of FIG. 3 a nut 8 is attached to the recessed portion 6 of the central portion 4 of the rail 1. As shown, the nut 8 is attached to a surface facing away from the concrete ceiling during use. The nut 8 may be attached to the rail 1 by welding or adhesive. It will be appreciated that in this example the rail 1 does not require an opening as per the examples of FIGS. 1 and 2, however the recessed portion 6 may include any opening aligned with the nut 8 to permit an end of the threaded rod to pass into the recess 7.
In an alternative example similar to that of FIG. 3 the nut 8 may be attached to the rail 1 within the recess 7, for example by welding or adhering the nut 8 to the recessed portion 6. In such an example the rail 1 will include an opening such as that shown in FIG. 1.
In the example of FIG. 4 the recessed portion 6 comprises a threaded hole 10 for attachment of a male threaded part of the suspended ceiling system. The threaded hole 10 may be formed by drilling or punching a hole and then tapping a thread, or by drilling a self-tapping screw into the recessed portion 6 and then removing it.
In the example of FIG. 5 the recessed portion 6 of the rail 1 includes a boss 11 extending from the recessed portion 6 in a direction away from the concrete ceiling. The boss 11 includes a threaded hole 12. The boss may be formed by punching material from the rail 1, or by attaching a separate boss to the rail 1, for example by welding or adhesive. In the example of FIG. 5 the recess 7 formed by the recessed portion 6 allows an end of the threaded rod of the suspended ceiling system to enter the recess 7 during use, and ensures that the nailing regions 2a, 2b can sit flush against the concrete ceiling.
In the examples of FIGS. 6 and 7 the rail 1 has an alternative profile comprising a central portion 4 and opposing side wings 5a, 5b, but without any recessed portion 6. Accordingly, the nailing regions 2a, 2b are larger. The rail 1 of FIGS. 6 and 7 has a generally 'U' shaped profile.
In the example of FIG. 6, the rail 1 includes a boss 13 that is formed in the central portion 4, and the boss 13 has a threaded hole 14. The boss 13 is as described with reference to FIG. 5.
In the example of FIG. 7, the rail 1 includes a boss 13 mounted to the central portion 4. The boss 13 is formed by embedding a threaded grommet 15 into an opening in the central portion 4. The threaded grommet 15 may be welded onto the central portion 4, or may be attached by an interference fit between an opening in the central portion 4 and the threaded grommet 15.
In an alternative example a rail 1 having the profile of FIGS. 6 and 7 (i.e., no recessed portion) may have a nut 8 attached to the central portion 4 as per the example of FIG. 3.
In alternative examples, the boss 11, 13 described above may have an external (male) thread, for attachment of a female threaded part of the suspended ceiling system.
It will be appreciated that the nuts 8, threaded holes 10, and/or threaded bosses 11, 13 as described above provide an attachment feature for attachment of a part of a suspended ceiling system.
FIG. 8 illustrates the example rail 1 of FIGS. 1 and 2 nailed to a concrete ceiling 16 with the nut 8 positioned in the recess 7 between the rail 1 and the concrete ceiling 16. As shown, nails 17 have been driven through the nailing regions 2a, 2b to attach the rail 1 to the concrete ceiling 16.
A plurality of nails 17 can be used to attach the rail 1 to the concrete ceiling 16. For example, a pair of nails 17 (one in each nailing region 2a, 2b) may be provided at five centimeter spacings along the length of the rail 1. It will be appreciated that the number of nails 17 can be determined based on the load of the particular suspended ceiling system, and that as there are no corresponding anchors in the concrete ceiling 16 as many nails 17 as needed can be easily provided.
The nails 17 could be driven through the nailing regions 2a, 2b and into the concrete ceiling 16 by, for example, a gas powered nail gun such as the Pulsa™ range of nail guns produced by SPIT PASLODE™.
Accordingly, the rail 1 can easily be attached to the concrete ceiling 16 by nails 17.
As shown in FIG. 8, a suspended ceiling system 18 is then attached to the rail 1, in particular to the nut 8. In particular, a threaded rod 19 of the suspended ceiling system 18 is screwed into the nut 8 through the opening 9. An opposite end of the threaded rod 19 is attached to a frame 20 that supports ceiling panels 21. A series of rails 1, threaded rods 19, and frames 20 can be arranged to provide coverage over an entire ceiling.
A plurality of rails 1 can be nailed to the concrete ceiling 16 in parallel and/or perpendicular arrangement to provide a grid of attachment points for the suspended ceiling system 18.
It will be appreciated that the mounting arrangement shown in FIG. 8 also applies to the example rails of FIGS. 3 to 7.
FIGS. 9A and 9B show an alternative example rail 1, in which the rail 1 is used for attaching a hooked suspension wire 23 of the suspended ceiling system.
In the example of FIGS. 9A and 9B the rail 1 has the same profile as illustrated in FIG. 1, particularly a central portion 4, opposing side wings 5a, 5b, and a recessed portion 6 in the central portion 4. The profile is generally 'U' shaped. First and second nailing regions 2a, 2b are provided for attaching the rail 1 to the concrete ceiling as illustrated in FIG. 8. In this example, instead of a nut or other thread, the rail 1 is provided with a plurality of openings 22 arranged along the recessed portion 6. The openings 22 are configured to receive a hooked wire 23 as shown in FIG. 9B. The hooked wire 23 includes a suspension wire 24 that is attached to the frame (20, see FIG. 8). The hooked wire 23 also includes a hook 25 that can pass through an opening 22 in the recessed portion 6 of the rail 1 to attach the frame (20, see FIG. 8) to the concrete ceiling (16, see FIG. 8).
Accordingly, the openings 22 provide an alternative attachment feature for attachment of the suspended ceiling system to the rail 1.
In some examples, the rail 1 may be provided with a combination of any of the attachment features of FIGS. 1 to 7 and 9A and 9B, so that the rail 1 can be used with either threaded rods 19, as shown in FIG. 8, or hooked wires 23, as shown in FIG. 9B.
As shown in FIG. 10, the rails 1 preferably have a stackable profile. In particular, the opposing side wings 5a, 5b are preferably diverging as they extend away from the central portion 4 such that multiple rails 1 can be stacked one on top of another, as illustrated. Such stackability provides for reduced storage and transport space, saving cost and resources. FIG. 10 illustrates the 'M' shaped profile of FIGS. 1 to 5, but the 'U' shaped profile of FIGS. 6 and 7 may also have diverging side wings 5a, 5b to allow the rails 1 to be stacked as shown in FIG. 10.
As shown in FIG. 11, in some examples the rail 1 may have ancillary attachment features. For example, as shown in FIG. 11, one or both opposing side wings 5b, 5b may include one or more holes 26 for attaching ancillary items, such as cables, pipes, or hoses. Accordingly, ancillary items such as cables, pipes, and hoses may be attached to the rails 1, in particular the holes 26, by ties or fasteners. Accordingly, the rails 1 can be used to route services in addition to providing attachment of the suspended ceiling system to the concrete ceiling.
In alternative examples, the rail 1 have one or more clips or other fasteners attached thereto, particularly on one or both of the side wings 5a, 5b, for attachment of ancillary items such as cables, pipes, and hoses.
As shown in FIG. 12, in some examples the rail 1 may have an ancillary item 27 pre-installed, that is, attached to the rail 1 before the rail 1 is nailed to the concrete ceiling. The ancillary item 27 may be attached to the rail 1 by clips 28, as illustrated. In this example, installation of the rail 1 by nailing to the concrete ceiling will simultaneously install the ancillary item 27. The ancillary item 27 may be provided with connectors or joints to enable connection to ancillary items of other rails 1 on the concrete ceiling.
The rails 1 described herein may be manufactured from a sheet material by a folding process. Preferably, the rails 1 comprise a sheet metal, in particular a sheet steel. The sheet steel preferably has a maximum thickness of 3 millimeters to permit the nails to puncture the rail 1 and attach to the concrete ceiling. In examples, the rail 1 may be manufactured from a sheet steel material having a thickness of between 0.6 millimeters and 3 millimeters, for example 1 millimeter, 2 millimeters, 2.5 millimeters, or 3 millimeters.
Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings).
1. A rail for attaching a suspended ceiling system to a concrete ceiling, the rail comprising:
a nailing region that is attachable to the concrete ceiling by a plurality of nails, and
an attachment feature for attachment of a part of the suspended ceiling system to the rail.
2. The rail of claim 1, wherein the attachment feature comprises a thread for attachment of a threaded part of the suspended ceiling system.
3. The rail of claim 1 or claim 2, wherein the attachment feature comprises a nut.
4. The rail of claim 3, further comprising a recessed region arranged such that when the rail is nailed to the concrete ceiling the recessed region defines a cavity between the rail and the concrete ceiling, wherein the nut is positioned in the recessed region, and wherein the rail further comprises an opening corresponding with the nut.
5. The rail of claim 4, wherein the recessed region is formed along the length of the rail.
6. The rail of any of claims 3 to 5, wherein the nut is attached to the rail, for example welded to the rail.
7. The rail of claim 2, wherein the rail comprises a boss extending from the rail, the boss comprising the thread for attachment of a threaded part of the suspended ceiling.
8. The rail of any preceding claim, wherein the attachment feature comprises an opening for attachment of a hooked wire of the suspended ceiling system.
9. The rail of claim 8, wherein the rail comprises a recessed region arranged to define a cavity between the rail and the concrete ceiling when the rail is nailed to the concrete ceiling, and wherein the opening is formed in the recessed region.
10. The rail of any preceding claim, wherein the rail comprises a generally 'U' shaped profile having a central portion comprising the nailing region and opposing side wings.
11. The rail of claim 11, wherein the central portion of the rail comprises a recessed region arranged to define a cavity between the rail and the concrete ceiling when the rail is nailed to the concrete ceiling.
12. The rail of claim 11, wherein the attachment feature is arranged in the recessed region.
13. The rail of claim 11 or claim 12, wherein the nailing region comprises first and second nailing regions extending along opposite sides of the recessed region.
14. The rail of any preceding claim, wherein the rail comprises a steel sheet material.
15. The rail of claim 14, wherein the nailing region comprises a maximum thickness of 3 millimeters.
P306425EP
EP
20203697.6
Illinois Tool Works INC.
8
DH
20210415
E04B
E04C
US
4926606
A
HANSON CARL E [US]
19900522
X
1,14,15
A
2-13
* column 5, line 25 - column 7, line 54; figure 20 *
DE
2435301
A1
RIGOLA WERK SCHMIDT JULIUS
19760212
A
1-15
* page 4, paragraph 2 - page 7; figures 3-5 *
Lopes, Claudia
The Hague
20210406
US
4926606
A
19900522
NONE
DE
2435301
A1
19760212
NONE