Technical Field of the Invention

The present invention relates to a fastening device for providing a female connection unit, such as a nut or a threaded hole, in relation to an opening in a wall. A system for fastening two or more elements together using such a fastening device is also presented. The invention further relates to a stabilizing device for use with the fastening device for an improved connection. More specifically, the invention relates to the provision of fastening means for an element having an opening in a wall for installing a fastening device, the fastening device comprising a back side section with a female connection unit, such as a threaded hole, and a front side section connected to the back side section. The back side section is configured to be inserted through the opening in the wall. The invention also relates to a method for fastening two or more elements together using said fastening device and system, and possibly also by using the stabilizing device in connection with the fastening device.

Background for the Invention

When fastening elements together, there is often a need to be able to position a fastening point, such as a threaded hole, in relation to another element, and to provide a fastening point or anchoring point that is movable or slidable. There may also be a need to be able to replace fastening elements, typically if the fastening point comprises threads or other elements in risk of wear and tear or other damage. Often, it is also the case that one does not have access to the back side of an element to be assembled, or that the access is limited or difficult, for example if it is a larger wall, or if the element is a hollow profile, such as a tube, where the fastening point may be on an inside wall of the tube, as is typically the case when mounting guardrails for roadway barriers for example.

In many occasions, especially for roadway barriers and safety systems, there is a need to fasten two or more hollow profiles, for example connecting a guide rail to multiple vertical posts for securing a bridge, a stairway or a road. Especially when it comes to roadside barriers, one challenge is the varying terrain and obstacles in the road, resulting in that the attachment point may deviate slightly. It is advantageous to have the possibility to adjust the connecting profiles to each other, not having to fasten them at fixed points and it is advantageous that the fastening device or fastening system accepts a tolerance in the location of the elements to be fastened. Without such possibility for adjustments, connecting such elements requires a high degree of precision which may be difficult and also time consuming.

Blind fastener systems are typically used where the structure design or the assembly sequence does not allow access from both sides of the assembly. Such systems can provide a blind nut, for installing a bolt, or a blind bolt, for installing a nut.

It is known to use a hammerhead bolt or a T-bolt for the purpose of connecting two hollow profiles. A bolt with a T-shaped head is then inserted into a slot in one of the profiles, and rotated 90 degrees, so that it can not come out. The bolt is secured with a nut on the inside of the connecting profile. In order to ensure that the bolt does not rotate back or rotate further so that it can come back out of the slot, a special lock washer is installed on the bolt on the outside of the pipe, preventing rotation. The lock washer is installed partly on the outside of the pipe, and partly on the inside, covering a part of the bolt, and is configured so that it can not rotate inside the slot, thereby also preventing rotation of the bolt when the nut is installed. Such lock washers have a complex geometry, and due to this, the washers are typically made of plastic. These washers are vulnerable to cold weather, making them brittle and fragile, resulting in that the washer often cracks during installation.

Other blind bolt solutions are also known for similar purposes. Blind bolts protrude out from the element in which it is installed. In many occasions, this may be a disadvantage for example during storage or transportation where they may get damaged or they may damage other equipment.

Various types of blind rivet nuts are also known, where an internally threaded tubular sleeve is anchored from one side by means of riveting by deforming the material of the nut. US patent application US3411398A describes such a blind rivet nut. If the nut needs to be replaced, for example due to thread damage, the nut must be drilled off before a new nut can be installed.

For blind rivet nuts, the nut is installed in a predrilled hole and it is therefore not possible to adjust the anchoring point.

KR20090068025A presents a safety fence comprising many posts (110) arranged on a road or a bridge and provided with a coupling hole (111), a beam (120) with the closed cross section connecting the posts and having a fastening hole (131) corresponding to the coupling hole (111) of the post, a fastening member (130) provided with a head (132) being rotated after being inserted into the fastening hole, and a coupling member (140) coupled to one end of the fastening member. There is a need for a fastening device that allows for blind fastening with the possibility to adjust the exact location of the anchoring point, that is easy to install and that comprises simple and reliable parts. Moreover, there is a need for a fastening device that provides the possibility to anchor a blind nut, or a female connection unit, from one side only with the possibility to adjust the exact location of the anchoring point.

Summary of the Invention

An object of the present invention is to provide a fastening device being able to be set in an element from one side only, i.e. with access only from one side of the element. It is also an object to provide an easy-to-install fastening device for more efficient and improved fastening of elements. It is also an object to provide a fastening device that accommodates the misalignment between objects to be assembled. More specifically, it is an object to provide an adjustable and easily replaceable female connection device, such as a threaded hole or a nut, to an element that can be anchored on the blind side and set from the outside wall of the element. It is specifically an object that the female connection device does not require material deformation in order to be anchored to the elements, so that the part is easily movable, replaceable and also reusable. It is also an object that the device may be anchored and fastened in situ, not requiring any installation or assembling process prior to transportation for example. Another object of the invention is to provide a fastening system that reduces or eliminates protruding parts from the elements to be assembled. Yet another object of the invention is to provide a fastening system with enhanced stability in connection with curve shaped elements.

The invention utilizes a device comprising a female connection unit, such as a a nut, that can be inserted through an opening of an element whilst retaining another end of the device with a hand or a tool from the front side, allowing it to be inserted by one person, and only one-handed. The female connection unit may typically be a threaded hole. By utilizing dimensions that allow passing through the opening in one direction and prevent passing in another, the device provides an easy-to-install fastener without the need for additional parts for placing the female connection unit and without the need for deformation of the part. It is the geometrical shape in the different geometrical planes and the method used for installation that enables this simple and functional blind fastener. The female connection unit accepts a corresponding male connection unit, for making up a connection between the elements to be assembled. The female connection unit may preferably be a threaded hole, while the male connection unit may be a threaded bolt. Although the figures in this specification and their relating description refers to a threaded hole and a threaded bolt, it shall be understood that these are used as examples of the female and male connection units, and other embodiments of connection units may apply to the same embodiments of the invention.

Thus, in a first aspect, the present invention relates to a fastening device for providing a female connection unit in relation to an opening in a wall, the wall having a front side and a back side. The device comprises a back side section comprising the female connection unit and a front side section connected to the back side section. The back side section has dimensions allowing it to be inserted from the front side of the wall through the opening, and preventing it from exiting the opening when arranged such that the female connection unit is accessible through the opening by a corresponding male connection unit. The front side section allows for controlling the position and orientation of the back side section from the front side, and for stabilizing the back side section with the female connection unit on the back side of the wall. According to an embodiment of the invention, the fastening device is moveable within the opening in the wall, for locating the female connection unit in a desired location. This feature ensures that a certain tolerance is allowed when assembling two elements together using the fastening device.

The fastening device may comprise a connecting section connecting the front side section and the back side section, and that may be configured to be allowed to rotate about at least two different axes inside the opening in the wall. This allows for the back side section to have dimensions that allow it to be inserted in through the opening in the element, but that prevent it from exiting the opening when rotated, and specifically when rotated to the orientation that is suitable for placing the female connection unit so that it is accessible for a corresponding male connection unit. In one embodiment of the invention, the front side section is arranged away from the longitudinal axis of the female connection unit, such that when said longitudinal axis is arranged normal to the backside of the wall, the front side section on the front side of the wall can be pressed towards the wall, resulting in that the back side section will be pressed in a direction towards the backside of the wall and kept stable relative to the wall. The back side section may be configured with a first support surface arranged normal to the longitudinal axis of the female connection unit for supporting the back side section towards the backside surface of the wall. Furthermore, the front side section may be a planar or curved plate shaped element conformed to the shape of the front side of the wall providing a second support surface for supporting the front side section against the front side of the wall. The first and/or second support surface may be configured to cover at least part of the opening in the wall so that when the female connection unit is positioned, the opening may be at least partly closed by the support surface(s). This may help prevent water and dirt from entering in through the opening. The back side section may be generally planar and may have a width W2 and a thickness T2, and the opening in the wall may have a width W1 and a thickness T 1 , where W2 may be smaller than W1 and T2 smaller than T1. The female connection unit may, in a preferred embodiment, be a threaded hole configured for receipt of a corresponding threaded bolt (40).

It is presented a stabilizing device for use with a fastening device according to one or more of the preceding paragraphs, wherein the stabilizing device comprises an intermediate section with a locking arrangement configured to engage with the front side section of the fastening device, interlocking the two devices, and wherein, when interlocked, the intermediate section is positioned in a plane between the front side section and the back side section of the fastening device, and with a gap towards the back side section allowing it to be arranged on the opposite side of the wall relative to the back side section. The intermediate section may comprise an elongated opening at one end allowing for the connecting section of the fastening device to be moved into the opening and wherein the locking arrangement is a set of locking ears at least partly overlapping the front side section as the connecting section is moved into the opening. Furthermore, the intermediate section may comprise an opening, preferably a hole, for allowing the male connection unit to be inserted through the hole.

In a second aspect, the present invention relates to a stabilizing device and a fastening device, where the fastening device is according to one or more of the preceding paragraphs, wherein the stabilizing device comprises an intermediate section configured to engage with the front side section of the fastening device, stabilizing the two devices, and wherein, when engaged, the intermediate section is positioned in a plane between the front side section and the back side section of the fastening device, and with a gap towards the back side section allowing it to be arranged on the opposite side of the wall relative to the back side section. The intermediate section may comprise an elongated opening at one end allowing for the connecting section of the fastening device to be moved into the opening and further comprise a locking arrangement configured as a set of locking ears at least partly overlapping the front side section as the connecting section is moved into the opening. Furthermore, the intermediate section may comprise an opening, preferably a hole, for allowing the male connection unit to be inserted through the hole. According to one embodiment of the invention, the stabilizing device comprises a first set of support members projecting from the intermediate section for forming one or more surfaces of contact towards the wall, said support members being adapted to the shape of the wall. This feature ensures a more stable connection between the stabilizing device and the wall. Furthermore, the stabilizing device may comprise a second set of support members projecting from the intermediate section for forming one or more surfaces of contact towards a wall of another element, said support members being adapted to the shape of the wall of the other element. As with the first set of support members, the second set of support members ensures a more stable connection to the wall. Each support member in the first and/or second set of support members may be adapted to follow a similar curvature for providing a contact surface with a concave shape adapted to follow a convex shape on the outside of the element to which they are to be assembled.

In a third aspect, the present invention relates to a system for fastening two or more elements together using a fastening device according to the one or more of the preceding paragraphs, and a male connection unit. At least one of the elements to be assembled comprises an opening for installing the fastening device. According to one embodiment of the invention, the opening in the element is an oblong slot, the width W2 of the back side section of the fastening device is smaller than W1 of the slot, the thickness T2 is smaller than T1 of the slot, and W2 is larger than T 1.

Furthermore, the system may also comprise a stabilizing device according to the above paragraphs.

In a fourth aspect, the present invention relates to a method for fastening two or more elements together using a system according to the above paragraphs, wherein the method comprises the steps of:

- inserting the back side section of the fastening device through an opening in a wall by manipulating the front side section of the device;

- locating the back side section with the female connection unit in a desired location and so that it is accessible from the front side of the wall;

- inserting a corresponding male connection unit in the female connection unit from the front side of the wall while stabilizing back side section by manipulating the front side section, and

- tightening the connection between the male and female connection units.

The method may also comprise the step of placing a stabilizing device according to the above paragraphs on the front side of the wall and locking the fastening device to the locking arrangement before inserting the male connection unit. According to one embodiment of the invention, the method also comprises the step of loosening the connection between the male and female connection units and moving the female connection unit to another location in relation to the opening by manipulating the front side section and then re-tightening the connection.

Short Description of the Drawings

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

Figure 1 shows schematically a fastening device according to the invention in three perspective views from three different orientations ;

Figure 2 shows schematically a first step in the assembly process before inserting the fastening device through an opening in a wall;

Figure 3 shows schematically a second step in the assembly process where the fastening device is inserted into an opening in a wall;

Figure 4 shows schematically a third step in the assembly process where the fastening device is rotated about is longitudinal axis inside the opening;

Figure 5 shows schematically a step in the assembly process where the fastening device is rotated about its transverse axis inside the opening;

Figure 6 shows schematically a final step in the assembly process where a second element is placed next to the first element and a bolt is inserted through a hole into the fastening device;

Figure 7A, 7B and 7C shows schematically three embodiments of a stabilizing device in perspective view and seen from the front side;

Figure 8 shows schematically a stabilizing device and a fastening device connected to each other;

Figure 9 shows schematically a stabilizing device and a fastening device arranged on a horizontal tube shaped element; and

Figure 10 shows schematically a horizontal tube shaped element fastened to a vertical tube shaped element by use of a stabilizing device and a fastening device according to the invention.

Detailed Description of Embodiments of the Invention

The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to the terminology, method, and structure of a fastening device used for example for assembling parts of a guardrail system. However, the embodiments to be discussed next are not limited to such type of products, but may also be used for other types of elements to be assembled in a rigid manner.

Reference throughout the specification to“one embodiment” or“an

embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases“in one embodiment” or“in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more

embodiments.

Figure 1 shows schematically one embodiment of a fastening device 10 according to the invention in three perspective views from three different

orientations. This embodiment of the invention is especially suitable for use in fastening of a guardrail where two hollow profiles are to be fastened together. The fastening device 10 is intended to be arranged in relation to an opening in a wall of an element, the element typically having a size, shape or profile that restricts or limits access from the back side of the wall, such as for example a hollow tube, where access is limited to the outside of the tube. The fastening device 10 comprises a back side section 12, comprising a female connection unit, i.e. a threaded hole 11. In this embodiment, the threaded hole is arranged in a nut shaped element with a hexagon head. The purpose of the back side section 12 is to provide a female connection unit, such as a hole with threads, and therefor the external surface does not need to be of a type that can be torqued by hand or with a tool, a hexagon head is just one option. Likewise, if the thickness of the back side section is large enough, the threaded hole may be cut directly into the material forming the back side section, without requiring a nut shaped element or the like for arranging the threaded hole.

The fastening device further comprises a front side section 13 connected to the back side section 12. The front and back side sections 12, 13 may be connected by a connecting section 14. In an alternative embodiment, the connecting section may be part of the front and/or back side section, not forming an individual part or section of the fastening device. The front and back side sections 12, 13 both have a front side 12b, 13b, and a back side 12a, 13a. The embodiment of the fastening device shown in Figure 1 is especially suitable for being arranged in an oblong opening in a guardrail tube with its back side section 12 on the inside of the tube, and the front side section on the outside of the tube. In this embodiment, the back side section is generally planar, i.e. formed in a plate shaped form that may be flat or slightly curved. It may also have a nut shaped element protruding from the plate shaped form, for forming the female connection unit. The front side section is also a planar or a curved plate shaped element adapted to fit the outside of the tube, and preferably not extending considerably out from the surface of the tube after mounting it.

When mounting the fastening device in a wall 22 of an element 20, the first step is to hold the fastening device 10 in the front side section 13 using hands or a tool and ensuring that the back side section 12 is arranged so that it can be inserted through the opening 21 in the wall 22, as shown in Figure 2. The width W2 of the back side section 12 must be smaller than the length W1 of the opening 21 , so that the back side section 12 can be inserted through the opening 21. Next step is to insert the back side section 12 through the opening 21 , while retaining the front side section 13 on the front side of the wall 22, as shown in Figure 3 and indicated by the arrow in the figure. If the element 20 is a hollow profile, such as tube, as shown in Figure 3, the back side section 12 will now be situated on the inside of the tube, and the front side section 13 on the outside of the tube. The fastening device 10 can then be rotated approximately 90° clockwise or anticlockwise about its longitudinal axis inside the opening 21 , as shown in Figure 4 and indicated by the arrow, and then rotated again approximately 90° about its transverse axis with the front side section 13 towards the front side of the wall 22, in order to position the threaded hole 11 so that it is accessible for a corresponding threaded bolt 40 from the front side of the wall 22. In this orientation, the back side section 12 has dimensions larger than the opening 21 in the wall so that it can not come out. In this position, one side of the back side section, 12b, acts as a support surface towards the back side of the wall 22, and one side of the front side section, 13a, acts as a support surface towards the front side of the wall 22. The fastening device 10 can now be adjusted sideways by sliding it along the opening into the desired position, as indicated by the arrows in Figure 5, while maintaining the threaded hole 11 accessible. This is a key element of the invention that enables the threaded hole 11 , i.e. the anchoring point for the threaded connection, to be adjustable to account for misalignment between the elements to be assembled even after the threaded hole 11 has been installed in the element 20 to be assembled. In this embodiment, the back side section 12 is configured such that when in this final position, the back side section 12 can cover the opening 21. If the fastening device 10 as shown in Figure 5 is moved to the left, the front side section 13 will cover the part of the opening 21 that is not covered by the back side section 12, preventing water, dirt or other debris from entering into the profile.

The front and/or back side section 12, 13 may also be given a profile that corresponds to the profile of the wall 22 to which it is to be installed. For example, if the fastening device 10 shall be installed in a tube with a circular profile, the front and back side section 12, 13 may be curved in such a way that it follows the perimeter of the tube wall 22, preventing any protruding parts from the assembly.

Figure 6 shows an assembly where a fastening device 10 according to the invention is used for fastening a horizontal rail 20 and a post 30 of a guardrail. Due to the size and shape of front side section 13, there are no protruding parts, and the vertical post 30 may be installed close to the horizontal rail 20 with no or little gap between the profiles.

Figure 7A-C shows schematically a stabilizing device 50 for use together with a fastening device 10 according to the invention. The stabilizing device 50 is seen in a perspective view from the front side, i.e. from the side where the male connection unit 40 is to be installed. One of the purposes of the stabilizing device 50 is to serve as a locking feature for locking in place or retaining the fastening device 10 to the wall 22 in which it is installed, prior to installing the male connection unit 40. Another purpose of the stabilizing device 50 is to provide an improved surface of contact, especially when the outer surfaces of the two elements to be assembled 20, 30 do not correspond to each other. Such a case may for example be where at least one of the elements to be assembled has a convex outer shape, such as for example a tube with a circular cross section. The stabilizing device 50 and the fastening device 10 may be configured such that they are self locking.

In the embodiments shown in Figure 7A-C, the stabilizing device 50 comprises an intermediate section 51 with a hole 52, intended for allowing the male connection unit 40 to be installed. Moreover, the intermediate section 51 , comprises an opening 53, for allowing the connecting section 14 of the fastening device 10, to be slidably moveable inside the opening. At the upper and lower ends of the front side, on the same side of the stabilizing device as the opening 53 (right side in Figure 7), a set of locking ears 54 optionally are provided (See Figure 7B-C). The purpose of the locking ears 54 is to serve as a locking arrangement for retaining the front side section 13 of the fastening device 10 towards the front side of the wall 22 of the element 20. This ensures that when the bolt 40 is installed through the hole 11 in the fastening device 10, the fastening device 10 will not be allowed to rotate so that the back side section 12 moves away from the wall 22, but will remain in its position relative to the wall 22.

In some occasions, the fastening device 10 may be used to assemble two elements that have outer shapes that do not correspond to each other, for example if both elements are circular tubes. In such cases, it is advantageous that the surfaces of contact between the fastening device 10 and/or the stabilizing device 50 towards the elements 20, 30 are configured for such shapes. For enhanced stability and improved contact of surface towards the walls 22, 32 of the elements 20, 30 to be assembled, the stabilizing device 50 shown in Figure 7A-C comprises a first set of support members 55 extending outwards from the back side of the device. In the embodiment in Figure 7A-C, the first set of support members 55 are intended to provide improved contact surfaces towards a horizontal circular shaped tube, such as the outside of the wall 22 of element 20. Without these support members, the surface of contact between the more or less flat intermediate section 51 and the curved tube would be instable, tipping about a small contact area. The contact surfaces provided by the support members 55, may be in addition to or in stead of a contact surface lying along the intermediate section 51. In this embodiment, at least two such support members should be used for stability (in Figure 7C, an upper support member is hidden behind the section 51), and arranged on each side of the instable contact surface between the intermediate section and the tube 20.

In the embodiment shown in Figure 7C, the stabilizing device 50 has a second set of support members 56 extending outwards from the front side of the device. The second set of support members 56 is, in this embodiment, configured for support of a rounded element, such as for example a vertically arranged circular tube, such as the outside of the wall 32 of element 30. The second set of support members comprises in this embodiment four protruding sections, two upper and two lower, that together forms contact surfaces adapted to the shape of the connecting element, for example so that the upper sections forms sections of an arc, and the lower sections forms sections of an arc, preferably with a radius of curvature adapted to the shape of the corresponding element to be assembled 30. The stabilizing device 50 may be provided with various shapes of the first and second set of support members 55, 56, depending on the outer shape of the elements 20, 30 to be assembled, while the intermediate section 51 with the hole 52 and the opening 53 may maintain its shape in order to fit to the same fastening device. In one embodiment, the opening 53 may be configured to overlap the area where the hole 52 would be placed, such that only one opening is necessary. When installing the fastening device 10 using the stabilizing device 50, the fastening device 10 is first installed through the opening 21 in the wall 22 of for example a tube 20, and rotated into a position as shown in Figure 5. The stabilizing device 50 can then be positioned with its back side towards the same wall 22, the first set of support members 55 resting on the wall 22, and positioned next to the fastening device 10. The fastening device 10 can then be moved sideways so that the front side section 13 of the fastening device 10 is inserted behind the locking ears 54 of the stabilizing device 50, as shown in Figure 8 and Figure 9. The fastening device 10 is in correct position when the female connection unit 11 through the fastening device 10 overlaps the hole 52 through the stabilizing device 50. At this stage, the two parts 10, 50 are locked to each other, due to the locking ears 54, and to the wall 22, and it is not required to hold the fastening device 10 in place for installing the male connection unit 40. The only movement allowed at this stage is a translational movement of the interlocked fastening device 10 and stabilizing device 50 within the opening 21 in the wall 22, i.e. a horizontal sliding movement along an oblong opening 21 along the longitudinal axis of the tube 20 in the embodiment shown in Figure 9 (opening 21 not shown in Figure 9).

Figure 10 shows schematically how two elements, in this embodiment a horizontal and a vertical tube shaped element 20, 30, can be fastened together using a system according to the present invention. The fastening device 10 is mounted into an opening 21 in the wall 22 of the horizontal tube 20 and connected/interlocked with the stabilizing device 50, which rests with its support members 55 on the outside of the wall 22. The stabilizing device 50 with the fastening device 10 can now be slidably moved inside the opening 21 in the wall 22, in order to position the threaded hole 11 in a desired location in relation to the vertical tube 30. A bolt 40 is positioned in a hole in the vertical tube 30 and inserted through the hole 52 in the stabilizing device 50 and into the threaded hole 11 in the fastening device 10, where it is tightened by the threads. If it is required at a later stage, the bolt 40 may be loosened and the stabilizing device 50 and the fastening device 10 may be moved sideways along the longitudinal axis of the tube 20, in order to relocate the position of the threaded hole 11 , before the bolt 40 is reinstalled and tightened to the threaded hole 11.