Technical Field
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The invention relates to a fastening device for fastening a safety wire to a roof equipment. Furthermore, the invention also relates to a fall protection system comprising such a fastening device.
Background
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Different fastening devices for fastening or attaching a safety wire to a roof equipment of a roof are provided on the market. Such a fastening device may comprise one or more fastening means for fastening the fastening device to a roof equipment and a holder for holding a section of a safety wire. Examples of roof equipment are ladders, snow fences, safety equipment and solar panels.
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The mentioned fastening devices are generally part of fall protection systems which are required to fulfil safety requirements stipulated by government authorities or industrial standards.
Summary
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An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.
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The above and further objectives are solved by the subject matter of the independent claims. Further advantageous embodiments of the invention can be found in the dependent claims.
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According to a first aspect of the invention, the above mentioned and other objectives are achieved with a fastening device for fastening a safety wire to a roof equipment, the fastening device comprising:
- fastening means for fastening the fastening device to the roof equipment; and
- a holder device attached to the fastening means, the holder device comprising a plurality of deformation sections connected to each other in parallel with an extension direction of a section of the safety wire in the holder device to form a holder for holding the section of the safety wire, wherein at least one deformation section among the plurality of deformation sections is configured to deform when a load equal to or larger than a threshold load is applied at the holder device.
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The load applied at the holder device may be a load directly applied at the holder device, e.g., by a glider running on the safety wire, or indirectly via the safety wire. Since the holder device holds a section of the safety wire a load applied to the safety wire will indirectly also be applied the holder device.
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The fastening means may be any means known in the art for fastening the fastening device to the roof equipment.
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The threshold load may be considered as the load value when the holder device is configured to start to deform so as to absorb energy. The threshold load may be determined and comply with governmental and/or industrial regulations.
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Thereby, a fastening device is provided that fastens the safety wire to the roof equipment and at the same time provides an energy absorption unit of a fall protection system. Hence, a combined fastener and energy absorber is provided with the fastening device herein disclosed.
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In an embodiment of a fastening device according to the first aspect, the fastening means comprises
- a first fastening leg connected between a first deformation section of the plurality of deformation sections and a first fastening section of the roof equipment; and
- a second fastening leg connected between a second deformation section of the plurality of deformation sections and a second fastening section of the roof equipment.
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With the use of different configurations of fastening legs, e.g., the number of fastening legs and the location of the fastening legs, the energy absorbing properties of the fastening device can be configured and hence adapted to different applications.
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In an embodiment of a fastening device according to the first aspect, the fastening means comprises one or more intermediate fastening legs connected between one or more intermediate deformation sections of the plurality of deformation sections and one or more intermediate fastening sections of the roof equipment.
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In an embodiment of a fastening device according to the first aspect, the first deformation section is a first end deformation section and the second deformation section is a second end deformation section of the plurality of deformation sections.
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In an embodiment of a fastening device according to the first aspect, each fastening leg is connected between a deformation section and a fastening section in a first angle
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In an embodiment of a fastening device according to the first aspect, each fastening leg is connected between a deformation section and a fastening section in a first angle or in a second angle.
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By adapting the angle(s) for the attachment of the fastening legs, the energy absorbing properties of the fastening device can be configured.
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In an embodiment of a fastening device according to the first aspect, the fastening legs are connected between a deformation section and a fastening section in an alternating pattern in the first angle and the second angle.
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In an embodiment of a fastening device according to the first aspect, each fastening leg is configured to deform at a first predetermined threshold value.
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In an embodiment of a fastening device according to the first aspect, each fastening leg is configured to deform at a first predetermined threshold value or at a second predetermined threshold value.
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By adapting the predetermined threshold value(s), the energy absorbing properties of the fastening device can be configured.
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In an embodiment of a fastening device according to the first aspect, two or more deformation sections among the plurality of deformation sections are configured to deform when a load equal to or larger than the threshold load is applied to the holder device via the safety wire.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections are serially connected to each other and configured to serially deform in a sequential order.
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In an embodiment of a fastening device according to the first aspect, each deformation section is configured to deform at a third predetermined threshold value.
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In an embodiment of a fastening device according to the first aspect, each deformation section is configured to deform at a third predetermined threshold value or at a fourth predetermined threshold value.
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Thereby, controlled deformation is provided when an excessive load is applied at the fastening device.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections encloses the section of the safety wire.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections together form a single helix enclosing the section of the safety wire.
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Thereby, simplified insertion or mounting of the safety wire in the fastening device is possible.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections together form a double helix enclosing the section of the safety wire.
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The double helix shape may resist higher loads than a single helix shape due to higher robustness.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections together form a cylinder enclosing the section of the safety wire.
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The cylindric configuration provides further degrees of freedom when designing the fastening device in respect of the energy absorbing properties.
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In an embodiment of a fastening device according to the first aspect, the plurality of deformation sections comprise one or more deformation initiators.
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By using deformation initiators further degrees of freedom is provided when designing the fastening device in respect of the energy absorbing properties.
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In an embodiment of a fastening device according to the first aspect, the section of the safety wire extends inside the holder device.
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According to a second aspect of the invention, the above mentioned and other objectives are achieved with a fall protection system for a roof comprising a fastening device according to any embodiment of the first aspect, a roof equipment and a safety wire.
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In an embodiment of a fall protection system according to the second aspect, the roof equipment is one or more in a group comprising: walkway, roof ladder, facade ladder, and ridge rail.
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Further applications and advantages of the embodiments of the invention will be apparent from the following detailed description.
Brief Description of the Drawings
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The appended drawings are intended to clarify and explain different embodiments of the invention, in which:
- Fig. 1 shows and illustrates a fastening device and a fall protection system according to embodiments of the invention;
- Fig. 2 shows a fastening device formed as a single helix according to embodiments of the invention;
- Fig. 3 and 4 show a fastening device formed as a double helix according to embodiments of the invention;
- Fig. 5 to shows a fastening device formed as a cylinder according to embodiments of the invention; and
- Fig. 6 and 7 illustrates different angles for attaching fastening legs according to embodiments of the invention.
Detailed Description
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Fig. 1 shows and illustrates a fastening device 100 and a fall protection system 400 according to embodiments of the invention. With reference to Fig. 1 the fastening device 100 comprises fastening means 102 for fastening the fastening device 100 to the roof equipment 300 and a holder device 110 attached to the fastening means 102. The holder device 110 comprises a plurality of deformation sections 112a, 112b,..., 112n connected to each other in parallel with an extension direction of a section of the safety wire 200 in the holder device 110 to form a holder 120 for holding the section of the safety wire 200. At least one deformation section among the plurality of deformation sections 112a, 112b,..., 112n is configured to deform when a load L equal to or larger than a threshold load LTh is applied at the holder device 110.
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The load applied at the holder device may be directly applied at the holder device 110 by e.g., a glider device 210 running on the safety wire 200, or indirectly via the safety wire 200. The glider device 210 may be part of a fall protection system and can also be denoted a fall arrester, a traveler, or a slider that is running on the safety wire 200. The glider device 210 may be connected to a safety harness which is equipped by a person moving on the roof.
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Fig. 1 therefore also illustrates a fall protection system 400 for a roof according to embodiments of the invention. The fall protection system 400 herein disclosed comprises a fastening device 100 according to any embodiments of the invention, a roof equipment 300 and a safety wire 200. It is realized that the fall protection system 400 may comprise any number of fastening devices 100, roof equipments 300 and safety wires 200.
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In embodiments of the invention, the roof equipment 300 is one or more in a group comprising: walkway, roof ladder, facade ladder, and ridge rail. The roof equipment 300 is fastened/attached to a roof according to conventional solutions. This is not illustrated in the Figs. of the present disclosure.
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Generally, it may be required that the fall protection system 400 should comply with safety requirements set by government authorities and/or industry standards. For example, on elevated structures such as roofs, there may be a requirement that approved fall protection systems must be present if the vertical drop is more than 2 meters. The safety requirement may further state that on roofs with low roof pitches or slopes, the roof must have arrangements that offer anchoring of persons if they are closer than 2 meters from the edge of the roof. For roofs with higher roof pitches, there is a requirement that persons on the roof be anchored at all times. Some solutions for securing persons on roofs include walkways, roof ladders, snow fences and the like on condition that they are installed in accordance with approved installation instructions. Other solutions include specific anchoring systems such as posts that are anchored to the roof and steel wires running between the posts. A person with personal fall safety equipment can hook onto the safety wires and can thereby move around on the roof. In any of these solutions, an exemplified approved system may be required to handle dynamic tests with a weight of 100 kg falling freely from 2.5 meters and static tests with a weight of 1000 kg hanging freely for 3 minutes. The present fall protection system 400 can easily be designed to fulfil such and other safety requirements.
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Fig. 2 shows in a side view a fastening device 100 according to embodiments of the invention. The plurality of deformation sections 112a, 112b,..., 112n in this case together encloses a section of the safety wire. Thus, it may be noted that the section of the safety wire extends or passes inside the holder device 110.
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In embodiments of the invention the plurality of deformation sections 112a, 112b,..., 112n form a single helix which encloses the section of the safety wire 200 for holding the same. The single helix design simplifies the insertion of the safety wire 200 in the holder device 110 since the safety wire 200 can be threaded into the holder device 110 by a simple operation.
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Moreover, as also disclosed in Fig. 2, the fastening means 102 may comprises a first fastening leg 104 connected between a first deformation section 112a of the plurality of deformation sections 112a, 112b,..., 112n and a first fastening section 304 of the roof equipment 300, and may further comprise a second fastening leg 104' connected between a second deformation section 112b of the plurality of deformation sections 112a, 112b,..., 112n and a second fastening section 304' of the roof equipment 300.
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In embodiments of the invention, with the previously described configuration the first deformation section 112a may be a first end deformation section and the second deformation section 112b may be a second end deformation section of the plurality of deformation sections 112a, 112b,..., 112n as also shown in Fig. 2. In such examples, one or more intermediate fastening legs 106 may be connected between one or more intermediate deformation sections of the plurality of deformation sections 112a, 112b,..., 112n and one or more intermediate fastening sections 306 of the roof equipment 300. Fig. 2 illustrates an example when one intermediate fastening leg is connected between the holder device 110 and the roof equipment 300. It is noted that any number of intermediate fastening legs may be arranged between the two end deformation sections of the holder device 110. Different configurations of fastening legs will result in different energy absorption properties so as to adapt to different applications.
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Furthermore, the fastening legs may also be configured to have specific deformation properties thereby configuring the energy absorption properties of the fastening device 100 with further degrees of freedom. Hence, each fastening leg may be configured to deform at a first predetermined threshold value; or each fastening leg may be configured to deform at a first predetermined threshold value or at least one second predetermined threshold value. In the first example, all the fastening legs have the same deformation properties whilst in the latter case different fastening legs may have two or more predetermined threshold values.
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Fig. 3 and 4 shows in a side view a fastening device 100 according to yet further embodiments of the invention. In the disclosed examples, the plurality of deformation sections 112a, 112b,..., 112n together form a double helix enclosing the section of the safety wire 200 for holding the same. The double helix design may resist higher loads than the single helix design since such a geometry may provide higher robustness. However, it may be more difficult to insert the safety wire in the holder device 110 in the double helix geometry compared to the single helix geometry.
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Fig. 5 on the other hand shows, in a side view, a fastening device 100 formed as a cylinder according to yet further embodiments of the invention. This means that the plurality of deformation sections 112a, 112b,..., 112n together form a cylinder enclosing the section of the safety wire 200 in its inside for holding the same. Each deformation section may in examples be constituted of two or more sandwiched or connected materials having different deformation properties as shown in Fig. 5. This embodiment may provide yet further degrees of freedom when designing and configuring the energy absorption properties of the fastening device 100. It is however noted that each deformation section may be produced from a single material having a single deformation property.
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In embodiments of the invention, two or more deformation sections among the plurality of deformation sections 112a, 112b,..., 112n are configured to deform. A special case is illustrated in Fig. 5 when the plurality of deformation sections 112a, 112b,..., 112n are serially connected to each other and configured to serially deform in a sequential order substantial along the section of the safety wire 200. This also applies to the examples shown in Fig. 2 to 4. The sequential deformation order may depend on predetermined threshold values of the deformation sections described herein. Hence, the serial coupling of the deformation sections can be seen as a serial coupling in an energy absorption perspective for controlled and guided deformation of the fastening device 100. Thus, the total deformation property may be considered as a sum of the individual deformation properties of each deformation section.
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Therefore, the deformation sections 112a, 112b,..., 112n may, similar to the fastening legs 104, have configured or configurable deformation properties so as to adapt the total deformation properties of the fastening device 100. Hence, each deformation section may in embodiments be configured to deform at a third predetermined threshold value; and/or each deformation section may be configured to deform at a third predetermined threshold value or at least one fourth predetermined threshold value.
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The deformation sections 112a, 112b,..., 112n may further comprise one or more deformation initiators 130, such as material weakenings, yielding zones configured tear apart, slits, cut-outs, etc., as shown in Fig. 5. The deformation initiators 130 may be arranged in a number of different geometries and configurations, e.g., at each deformation section, at only some deformation sections, etc. The predetermined threshold values will among other things depend on the deformation initiators. Generally, a deformation initiator may be designed to deform when being impacted by excessive load levels corresponding to different threshold levels. Such load or impact force threshold level may conform to regulatory requirements e.g., stipulated by government authorities and/or to standard requirements in the industry. The deformation initiators may in examples be considered to define/delimit a deformation portion of the fastening device 100.
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Fig. 6 and 7 illustrates different angles for connecting or attaching a fastening leg 104 between a deformation section 112 and a fastening section of a roof equipment according to embodiments of the invention. Fig. 6 shows a fastening device 100 in a side view and Fig. 7 shows the fastening device 100 of Fig. 6 in a front view. Each fastening leg 104 may be connected between a deformation section 112 and a fastening section in a first angle α. However, in embodiments each fastening leg 104 may connected or attached between a deformation section 112 and a fastening section in a first angle α and/or in at least one second angle β. The first angle α and the one or more second angles β may be defined in relation to a plane parallel to the extension of the holder device 110 as illustrated in Fig. 6 or in relation to a plane perpendicular to the extension of the holder device 110 as illustrated in Fig. 7.
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The layout of the fastening device 100, such as fastening angles and number of fasting legs, will impact the capability of the glider device 210 to hook-on to the holder device 110 during a fall accident. An example having good hook-on properties is when the fastening legs 104 are connected between deformation sections and fastening sections in an alternating pattern in a first angle α and in one or more second angles β. Especially, with angles defined as shown in Fig. 7.
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The present fastening device 100 may be produced from sheet metal parts bent and/or metal thread and/or moulded metal parts. The different parts of the fastening device 100 may thereafter be attached to each other by means of suitable attachment means known in the art. Non-limiting examples of attachment means are through holes combined with bolts or screws. Also, adhesive and welding may be used for attachment.
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Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.
