Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
MECHANICAL FUSE, USE THEREOF, AND METHOD FOR RECEIVING FORCES
Document Type and Number:
WIPO Patent Application WO/2014/041241
Kind Code:
A1
Abstract:
The invention relates to a mechanical fuse and its use. The invention also relates to a method for receiving forces. The mechanical fuse (1) comprises fastening points (2, 3) with an intermediate part (4) between them. The intermediate part comprises at least one breaking section (5) and at least one absorbing section (7, 8). The breaking section is arranged to break, when a force (F) that is bigger than a predefined force is directed to the fuse, whereby the fuse trips. After the fuse has tripped, forces are received by the absorbing section.

Inventors:
VAARASTO ERKKI (FI)
VON BOEHN-BUCHHOLZ ROBERT (FI)
Application Number:
PCT/FI2013/050871
Publication Date:
March 20, 2014
Filing Date:
September 10, 2013
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
PROMECO SOLUTIONS OY (FI)
International Classes:
F16F7/12; F16D9/06; F16F7/00; G01L5/06
Foreign References:
US3106989A1963-10-15
US5344096A1994-09-06
DE102006023688A12007-11-22
GB1366108A1974-09-11
JPS5576235A1980-06-09
Attorney, Agent or Firm:
KOLSTER OY AB (P.O. Box 148, Helsinki, FI)
Download PDF:
Claims:
Claims

1. A mechanical fuse that comprises:

a first fastening point (2) and a second fastening point (3) that are at a distance from each other;

an intermediate part (4) between the fastening points (2, 3); and at least one breaking section (5) in the intermediate part (4);

and the mechanical fuse (1) is arranged to trip, when a force (F) bigger than a predefined force acts on the fastening points (2, 3) and endeavours to move the fastening points (2, 3) away from each other, and the tripping makes the breaking section (5) break;

c h a r a c t e r i s e d in that

the mechanical fuse (1 ) comprises in addition to the at least one breaking section (5) at least one absorbing section (7, 8) that is arranged to receive forces after the breaking part (5) breaks; and

the absorbing section is arranged to keep the fastening points (2, 3) in their moved position after the force (F) has ended.

2. A mechanical fuse as claimed in claim 1 , c h a r a c t e r i s e d in that,

the absorbing section (7, 8) is a deforming section.

3. A mechanical fuse as claimed in claim 1 or 2, c h a r a c t e r i s e d in that,

the absorbing section (7, 8) is a permanently deforming section, in which a plastic deformation is arranged to take place.

4. A mechanical fuse as claimed in any one of the preceding claims; c h a r a c t e r i-s e d in that

the mechanical fuse (1 ) is an elongated piece made of sheet material. ^

5. A mechanical fuse as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that

the mechanical fuse (1 ) is formed of one uniform piece:

6. A mechanical fuse as claimed in any one of the preceding claims, characterised in that

the absorbing section (7, 8) comprises a wavelike geometric shape, the waviness of which is dimensioned to straighten after the mechanical fuse (1 ) has tripped and as the distance between the fastening points changes.

7. A mechanical fuse as claimed in any one of the preceding claims, characterised in that

the mechanical fuse (1) is an elongated piece that comprises two absorbing sections (7, 8) at a crosswise distance from each other;

the breaking section (5) is arranged between the absorbing sections

(7,8);

the breaking section (5) and the absorbing sections (7, 8) are on the same plane; and

the absorbing sections (7, 8) have a wavelike geometry and both comprise at least two waves (9).

8. A mechanical fuse as claimed in any one of preceding claims 1 to 3, characterised in that - Ρ:':·:

the mechanical fuse (1) comprises a separate absorbing component with at least one absorbing section, and a separate breaking component with at least one breaking section.

9. The use of a mechanical fuse, the fuse being as claimed in any one of preceding claims 1 to 8, c h a r a c t e r i s e d by

using at least one mechanical fuse (1 ) for fastening a hatch (24) to a device frame (25);

keeping the hatch (24) stationary in relation to the device frame (25) by means of the breaking section (5) of the fuse (1) before the mechanical fuse (1) trips; . : - :.

allowing the hatch (24) to move in relation to the device frame (25) by means of the absorbing section (7, 8) of the fuse (1), when the fuse (1) trips-' - -; ' keeping the hatch (24) connected to the device frame (25) by means of the absorbing section (7, 8); and allowing the hatch (24) to remain in the moved position in relation to the device frame (25) so that there is a gap (26) between the hatch (24) and device frame (25).

10. The use of a mechanical fuse, the fuse being as claimed in any one of preceding claims 1 to 8, c h a r a c t e r i s e d by

using at least one mechanical fuse (1 ) for fastening a cabin part (33) to a vehicle body (35);

keeping the cabin part (33) stationary in relation to the vehicle body (35) by means of the breaking section (7, 8) of the fuse (1 ) before the mechanical fuse (1 ) trips;

allowing the cabin part (33) to move in relation to the vehicle body (35) by means of the absorbing section (7, 8) of the fuse (1 ), when the fuse (1 ) trips; and

keeping the cabin part (33) connected to the vehicle body (35) by means of the absorbing section (7, 8) and in the moved position.

11. A method for receiving forces, the method comprising: using at least one mechanical fuse (1 ) with at least' one breaking section (5);

directing to the mechanical fuse (1 ) a traction force (F) that endeavours to lengthen its structure; and ; ; ί :

tripping the mechanical fuse (1), when the traction force (F) exceeds a force bigger than a predefined force, whereby the breaking section- (5)' breaks; > ·. .- :

c h a r a c t e r i s e d by

after the tripping, receiving the traction force (F) with at least one absorbing section (7, 8) arranged in the mechanical fuse (1 ); and

keeping the mechanical fuse in the extended state by means of the absorbing section.

Description:
Mechanical fuse, use thereof, and method for receiving forces

Background of the invention

[0001] The invention relates to a mechanical fuse capable of receiving a predefined force. After this force has been exceeded, the mechanical fuse will trip.

[0002] The invention further relates to the use of a mechanical fuse and a method for receiving forces.

[0003] A mechanical overload protective device, breaking pin, and a corresponding mechanical fuse is used when needing to protect a component or part against an oversize force and the ensuing breakage ^ Therefore, mechanical fuses comprise a breaking section that is dimensioned to endure normal operating^ conditions, but breaks when an oversize.; force sis di ' rectedtto it. However, defects have been detected in known mechanical fuses.

Brief description of the invention

[0004] It is an object of the present invention to provide a novel and improved mechanical fuse and its use. A further object is to provide a novel and improved method for receiving forces.

[0005] The mechanical fuse according to the invention is characterised in that it comprises in addition to the at least one breaking section at least one absorbing section that is arranged to receive forces after the breaking, section has broken; and that the absorbing section is arranged to keep fastening points in a moved position after the force has ended.

[0006] The use according to the invention is characterised by using at least one mechanical fuse for fastening a hatch to a device frame; keeping the hatch stationary in relation to the device frame by means of the breaking section of the mechanical fuse before the mechanical fuse trips; allowing the hatch to move in relation to the device frame by means of the absorbing 'Sec tion of the mechanical fuse when the fuse trips; keeping the hatch connected to the device frame by means of the absorbing section; and allowing the hatch to remain in a moved position in relation to the device frame,- in which case there is a gap between the hatch and device frame.

[0007] Another use according to the invention is characterised by using at least one mechanical fuse for fastening a cabin part to a vehicle body; keeping the cabin part stationary in relation to the vehicle body by means of the breaking section of the mechanical fuse before the mechanical fuse trips; allowing the cabin part to move in relation to the vehicle body by means of the absorbing section of the mechanical fuse when the fuse trips; and keeping the cabin part connected to the vehicle body by means of the absorbing section and keeping it in a moved position.

[0008] The method according to the invention is characterised by receiving, after the tripping, traction force with at least one absorbing section that is arranged in the mechanical fuse; and keeping the mechanical fuse in an extended state by means of the absorbing section.

[0009] The idea is that the mechanical fuse comprises at least one breaking section that is essentially a rigid section and adapted to break, when a force stronger than a predefined force is directed to the mechanical fuse. In addition, the mechanical fuse comprises at least one absorbing section that receives forces even after the breaking section has broken.

[0010] An advantage is that the absorbing section absorbs the forces after the fuse has tripped, thus making the reception of forces controlled. This way, it is possible to prevent sudden and unexpected consequences.

[0011] The idea of an embodiment is that the absorbing section is a deforming section. > -

[0012] The idea of an embodiment is that the absorbing section is a permanently deforming section. A plastic deformation then takes place in the absorbing section. The absorbing section remains in the deformed state after the force directed thereto ends. This may be advantageous in situations, where it is necessary to have a clearly detectable indication of the effect of the force. The deformed section is easy to detect visually at a distance. Further, the embodiment may be advantageous in situations, where there should not be any return movement toward the original position after the effect of the force.

[0013] The idea of an embodiment is that the absorbing section is arranged to absorb forces without breaking. The absorbing section is dimensioned taking into consideration the forces to be received so that it can alter its geometrical shape and/or its material thickness may change as a result of a change in its length. -

[0014] The idea of an embodiment is that the absorbing section is a deforming section that is adapted to lengthen when a longitudinally lengthening force is directed to the mechanical fuse.

[0015] The idea of an embodiment is that the absorbing section is a lengthening structure, wherein the absorbing section is in its initial state at a first length and deforms permanently into a second length under the forces directed to the fuse without an essential change in the cross-sectional surface area of the absorbing section. In practice, the absorbing section is thus formed into a shorter length and may straighten and lengthen under forces directed thereto. Length is thus stored in the absorbing section and taking it into use by altering the shape of the absorbing section requires energy.

[0016] The idea of an embodiment is that the absorbing section of the mechanical fuse is a permanently deforming lengthening structure, into which length is stored by means of a wavelike design. When a lengthening force effect is directed to such a wavelike geometrical form, the wave form straightens. This formation of geometry binds energy. At the same time, the straightening of the waveform releases length.

[0017] The idea of an embodiment is that the breaking and absorbing sections of the mechanical fuse are on the same plane. In addition, the absorbing section is wavelike. At its minimum, the waviness comprises one curved section, ' one wave, or one serrated formation. There may be absorbing sections on both sides of the breaking section, that is, the breaking section is between absorbing sections. Because the breaking section and absorbing sections are on the same plane, the mechanical fuse may have a relatively thin structure, which facilitates its positioning in place and also has a favourable effect on its appearance.

[0018] The idea of an embodiment is that the absorbing section of the mechanical fuse is wavelike and comprises at least two waves.

[0019] The idea of an embodiment is that the absorbing section of the mechanical fuse is wavelike and comprises at least three waves.

[0020] The idea of an embodiment is that the breaking section comprises at least one designed breaking point with one or more weakenings. The breaking of the breaking section under load then takes place in a controlled manner at the designed point. In addition, it is possible to easily adjust the magnitude of the force required for breaking by means of the weakenings.

[0021] The idea of an embodiment is that the breaking section comprises at least one thinned section, in which the cross-sectional surface area is smaller than that of the rest of the breaking section.

[0022] The idea of an embodiment is that the absorbing section is dimensioned so that it enables a change of at least 1 cm of length, preferably a change of at least 3 to 6 cm of length. [0023] The idea of an embodiment is that the mechanical fuse has one uniform structure formed of only one piece. This type of structure is simple, and it is easy to manufacture.

[0024] The idea of an embodiment is that the mechanical fuse is formed of sheet material. A sheet can be formed into a mechanical fuse of a desired shape by cutting, for instance by using laser cutting, waterjet cutting or flame cutting. Laser cutting has been found especially advantageous, because a laser-cut mechanical fuse is dimensionally accurate and has good surface quality. It is then possible to ensure that the mechanical fuse works in the designed way when forces are directed to it. Alternatively, it is possible to manufacture good-quality mechanical fuses with die cutting techniques by using a pressing apparatus and cutting tools.

[0025] The idea of an embodiment is that the mechanical fuse is formed of only one sheet piece.

[0026] The idea of an embodiment is that the mechanical fuse is an elongated piece that has fastening sections at its ends for fastening the mechanical fuse to the object to be protected and for transmitting the received forces to the structure.

[0027] The idea of an embodiment is that the mechanical fuse is entirely or partly made of stainless steel. The advantage of stainless steel is its toughness, which is advantageous in the deforming section of the mechanical fuse in particular. In addition, stainless steel is a corrosion-proof material. v

[0028] The idea of an embodiment is that the mechanical fuse is entirely or partly made of aluminium alloy. Aluminium is easy to work and it is also a light and weatherproof material.

[0029] The idea of an embodiment is that the structure is flat and sheet-like in shape.

[0030] The idea of an embodiment is that the mechanical fuse comprises at least one breaking section and at least one absorbing section that are arranged on top of each other. The structure is then called a sandwich structure.

[0031] The idea of an embodiment is that the mechanical fuse has a sandwich structure, wherein against at least one side surface of the breaking section, there is an absorbing section with corrugation or waviness, the direction of which is on a different plane than the side surface of the breaking section. When the direction of the corrugation is perpendicular to the side surface, the width of the mechanical fuse can be made relatively small, even though its thickness becomes greater at the same time. The corrugation or waviness achieves a controlled and permanent change in length. Length for deformation of the fuse is reserved for the corrugated or wavelike geometry. Deformation binds energy, whereby a dampening effect is achieved. The absorbing sections can be arranged on both sides of the breaking section or on one side only. The absorbing section may be made of the same material as the breaking section or of different material. The properties of the fuse can be influenced in a versatile manner by material selection and dimensioning. This type of mechanical fuse can be made of sheet material by using normal sheet metal working techniques. The structure is simple and the manufacturing cost low.

[0032] The idea of an embodiment is that the operation of the absorbing section of the mechanical fuse is based on friction. The required energy-absorbing ability can be formed by means of friction. Friction can be formed by means of one or more wedge surfaces, for instance, which also produces the feature that friction and the resisting force increase in relation to the moving distance. In addition, the wedge surfaces can be dimensioned to be self- retaining, in which case the absorbing section maintains its position after the received force has ended. With a wedge surface, it is also possible to provide deformation of the mating surface materials, which also efficiently absorbs energy. As an alternative to a wedge surface, the friction can be produced between mating surfaces by pressing the mating surfaces against each other by means of screws, rivets, springs or corresponding elements.

[0033] The idea of an embodiment is that the operation of the absorbing section of the mechanical fuse is based on utilising toothings or corresponding form surfaces.

[0034] The idea of an embodiment is to use the present mechanical fuse at the joint between a device cabinet frame and an opening hatch. The hatch may also be a door or cover. The device cabinet may be an electric or control cabinet containing electronic, electric, electromechanical or hydraulic actuators, instruments and components, for example. If pressure increases inside the closed device cabinet due to an explosion, electric arc, or some other matter, for instance, the hatch of the device cabinet endeavours to open. This opening can be resisted by a mechanical fuse. When the hatch opens under the forces directed to it, the breaking section of the fuse breaks, and then the force opening the hatch is received by the absorbing section. The number and location of mechanical fuses as well as the dimensions and material of each mechanical fuse can be selected as necessary by evaluating the forces directed to the hatch. The breaking section of the mechanical fuse may keep the hatch closed in a predefined position. In addition to the device cabinet, the mechanical fuse can be used between a hatch in a container, machine, device, or protective structure and a frame. The hatch may also be a discharge hatch that is intended to release overpressure from the inner space closed by the hatch. The fastening of the discharge hatch is dimensioned to act as a safety system against overpressure. Actual maintenance hatches can then be fastened without mechanical fuses.

[0035] The idea of an embodiment is to use, at the joint between the device frame and the opening hatch, one or more mechanical fuses, the absorbing section of which is arranged to lengthen permanently in its longitudinal direction, when forces are directed to it after the breaking part has broken. Thanks to the permanent change in length of the absorbing section; the hatch remains open so that there is a gap between the hatch and the device frame. This gap allows flue gases or other overpressure gas formed in an explosion or the like to exit the inner space closed by the hatch. In addition, any formed extra heat can exit through the gap. This application improves safety, because a damaged device cabinet or corresponding structure is easy to detect, when the hatch is partially open, and overpressure, harmful gases, and high temperature can also exit the structure. However, the hatch does not entirely detach from the frame and remains in place supported by the absorbing section.

[0036] The idea of an embodiment is that there are seals between the hatch and frame and the hatch is closed with one or more mechanical fuses. The seals remain correctly pressed against the sealing surfaces of the hatch and frame thanks to the rigid breaking section. The strength of the breaking section should therefore be dimensioned to endure at least the forces caused by the compression of the seals.

[0037] The idea of an embodiment is to use the present mechanical fuse in the interior structure of a passenger or control cabin of a vehicle, such as a train, airplane, coach, car, or ship. A seat, table, railing, or some other structure, component, or cabin part supported to the vehicle structure can be fastened safely with a mechanical fuse. The mechanical fuse keeps the cabin part firmly in place by means of the breaking section, but allows the cabin part to yield by means of the absorbing section, when a force that makes the break- ing section break is directed to the part. Due to a sudden movement, such as collision, deceleration or steering movement, a passenger may fall or be thrown in the cabin against a part that, thanks to the mechanical fuse, yields in a controlled manner. The falling energy of the passenger is dampened thanks to the absorbing section. When the absorbing section remains intact thanks to its structure, it keeps the cabin part fastened, and the passenger who has lost balance may take support from the yielding cabin part and regain balance. The cabin part that is fastened with the mechanical fuse yields but does not collapse. In addition, the cabin part that has yielded remains fastened to the vehicle body and does not cause additional problems. A tripped mechanical fuse is easy to detect and can be quickly replaced with a new one. All in all, the present mechanical fuse improves the safety of vehicles.

[0038] The idea of an embodiment is to use the present mechanical fuse in connection with a wire, rope, chain, or a corresponding power transmission element. The power transmission element can be protected against excessive tensile load with the mechanical fuse. .

[0039] The idea of an embodiment is that the mechanical fuse comprises a separate absorbing component with at least one absorbing section and a separate breaking component with at least one breaking section. The absorbing and breaking components can be fastened to the object to be protected separately, so this application differs in this respect from the integrated fuses described above. Other features and properties may be in accordance with the above-mentioned features or their combinations. If necessary, the absorbing and breaking components can be fastened spaced apart by a sideward distance, for instance. On the other hand, it is also possible to arrange the separate components on top of each other. This application further allows the adjustment of the absorption and/or breaking properties by using two or more absorbing components and/or two or more breaking components. If necessary, components dimensioned for different forces can be combined to provide a desired general effect.

[0040] The applications and features described above can also be combined to provide other applications and solutions applicable to various uses.

Brief description of the figures

[0041] Some embodiments of the solution are explained in more detail in the accompanying drawings, in which Figure 1a is a schematic perspective view of a mechanical fuse with absorbing sections having two waves on both sides of a breaking section, and Figure 1b shows the same fuse from the side,

Figures 2a and 2b are schematic views of a second mechanical fuse in its initial position, and Figure 2c shows the same fuse after a force directed to it has lengthened the structure longitudinally,

Figures 3a and 3b are schematic views of a mechanical fuse, the absorbing sections of which comprise three wave forms and gaps,

Figures 4a and 4b are schematic views of some alternative structures of a mechanical fuse, in which the breaking and absorbing sections are arranged on top of each other,

Figures 5a and 5b are schematic views of a mechanical fuse, in which the operation of the absorbing section is based on the utilisation of friction,

Figures 6a and 6b are schematic views of some mechanical fuses, in which the absorbing section comprises a tooth mechanism,-

Figure 7a is a schematic view of a device cabinet, the hatch of which is fastened with mechanical fuses to the cabinet frame, and Figure 7b shows the same device cabinet after a bigger than allowed opening force has been directed to the hatch, and ; .

Figure 8a is a schematic view of a component that is supported against a vehicle body with a mechanical fuse, and Figure 8b shows the same component after a bigger than allowed force effect has been directed to it.

[0042] For the sake of clarity, the figures show some embodiments in a simplified manner. Like reference numerals identify like elements in the figures.

Detailed description of some embodiments

[0043] Figures 1a and 1b show a mechanical fuse 1 that comprises a first fastening point 2 and a second fastening point 3 and -an intermediate part 4 between them. The intermediate part 4 is equipped with a breaking section 5 that is arranged to break when the fastening points 2, 3 are pulled away from each other by a force that is bigger than a predefined force. The breaking: section 5 may be equipped with a weakening 6, which may be a thinning, notch or the like, where breaking takes place in a controlled manner: In addition, the intermediate part 4 comprises two absorbing sections 7, 8 that are on both sides of the breaking section 5. The absorbing sections 7, 8 comprise a wavelike geometrical form. In this case, there are two waves 9. The structure of the intermediate part 4 may be symmetrical. The present structure may be made of one sheet piece by using normal sheet metal working techniques.

[0044] The first fastening point 2 may comprise a bent section 10 that may have an opening 11 for fastening elements. The second fastening point 3 may have one or more openings 12, by which the fastening point 3 may be fastened to a device frame by screws or rivets, for example. Dashed lines in Figure 1 b show openings 13 that may serve as alternative fastening means for the first fastening point 2. The mechanical fuse 1 may be fastened in different ways between two different structural parts, since the fastening mechanism and the used fastening elements are not significant to the basic idea.

[0045] The mechanical fuse 1 shown in previous Figures 2a and 2b differs from the embodiment shown in Figures 1a and 1 b in that the absorbing sections 7, 8 comprise three waves 9. It is possible to influence the ability of the absorbing section 7, 8 to receive energy by varying the number, geometry and cross-sectional area of the material of the waves. It is also possible to influence the size of the change in length that the waviness allows. The waveform may be the sine wave shown in the figures, for instance, but other waveforms are also possible. The range, or amplitude, of the wave form may be one of the adjustable parameters. Differing from Figures a to 2b, there may also be two or more breaking sections 5 and there may also be three or more absorbing sections 7, 8 or alternatively just one absorbing section.

[0046] Figure 2c shows the mechanical fuse 1 of Figures 2a and 2b after a force F directed to it has lengthened the structure longitudinally. Under the force F, the breaking section 5 has broken in a controlled manner at the weakening 6, after which the absorbing sections 7, 8 have received the force F and, in consequence, their waviness has straightened. The initial length L1 of the mechanical fuse 1 has then extended to its final length L2. The change in length may take place without an essential reduction in the material thickness of the wavelike section so that the length reserved for the wavelike geometric shape is released as the waviness straightens. Alternatively, the material may lengthen in addition to the straightening of the wavelike structure, and the cross-sectional area of the wavelike section decreases as a result.

[0047] The mechanical fuse 1 shown in Figures 3a and 3b is essentially like the one in the previous figures. The difference is that gaps 14 are formed in the absorbing sections 7, 8 to extend through the wavelike sections as if dividing the waves 9 into two parallel wave components. The purpose of the gaps 14 is to improve the formation ability of the waves. In some cases the waves 9 can be divided into parts by two or even more gaps.

[0048] The mechanical fuses 1 shown in Figures 4a and 4b differ from the previous embodiments in that the breaking section 5 and absorbing section 7 are not on the same plane, but the sections 5 and 7 are on top of each other. In addition, there is only one absorbing section 7 and instead of a curved wavelike shape, it has a serrated wave form. The absorbing section 7 may thus comprise a kind of corrugation 15. This type of mechanical fuse 1 can be made of sheet material. The breaking section 5 and the absorbing section 7 may be separate components that may be arranged on top of each other and fastened permanently to each other at the fastening points 2, 3. Alternatively, these components can be arranged on top of each other without fastening them to each other and connected to structural parts at the fastening points 2, 3. Yet another possibility is to arrange one or more breaking components and one or more absorbing components side by side in the lateral direction. The use of components allows for a modular structure, the properties of which are easy to alter as necessary.

[0049] The mechanical fuse 1 shown in Figure 4a comprises a fastening point 2 with a bend 10 like the structures shown in Figures 1a to 2b. In contrast/ the fastening point 2 in the structure of Figure 4b does not have a bend. 4 ; · '

[0050] Figures 5a and 5b show a mechanical fuse 1 ; in which the operation of the absorbing section 7 is based on friction. The breaking section 5 and the absorbing section 7 may be arranged on top of each- other and be fastened to each other by means of a pin 16 or a corresponding element at the second fastening point 3. The absorbing section 7 has a wedge-like opening 17, through which the pin 16 is arranged. Friction surfaces are formed between the wedge-like opening 17 and the pin 16 and receive energy after the breaking section 5 has broken. In addition, deformation takes place in the material of the absorbing section 7, because the wedge-like opening 7 narrows toward the end. Instead of the pin 16 and wedge-like opening 17, it is possible to use friction-forming elements 18 of other type. Friction can be formed between the absorbing and breaking sections arranged against each other by pressing them tightly against each other with suitable power or fastening elements. ■ ■ [0051] Figure 6a shows a mechanical fuse 1 , the absorbing section 7 of which comprises a tooth mechanism 19. The absorbing section 7 may comprise a first part 7a and a second part 7b with toothings 20, 21 arranged between them. After the breaking section 5 breaks, the parts 7a, 7b can move in relation to each other while the toothings endeavour to resist this movement. The toothing 21 may be arranged to grow bigger so that the resisting force increases in proportion to the moving distance. The tooth mechanism 9 may prevent the parts 17a, 17b from returning to their initial position after the force directed to the fuse 1 ends.

[0052] The solution shown in Figure 6b is similar to that of Figure 6a except that it also has one or more elastic sections 22 that may stretch after the breaking part has broken. The tooth mechanism 9 and elastic section may together absorb energy directed to the fuse 1. After the external force has ended, the tooth mechanism 19 can prevent the return movement. The elastic section 22 may be of rubber, for example.

[0053] Figures 7a and 7b show a device cabinet 23 that comprises at least one hatch 24 fastened with mechanical fuses 1 to a device frame 25. In addition to the device cabinet 23, this type of arrangement can be applied to containers and machine structures, for instance. There may be seals 26 between the hatch 24 and franie 25. The rigid breaking section of the mechanical fuse 1 keeps the seals 26 pressed against the sealing surfaces of the hatch and frame. The hatch 24 may be equipped with fastening parts 27 that may be connected to a bending part of the fastening point 2 of the fuse by means of a fastening screw 28 or the like. Between the fastening part 27 and fastening point 2, there may be a sleeve 29 for adjusting the compression of the seals 26. If overpressure is formed inside the device cabinet 23, container or corresponding space due to an explosion 30, for example, a force effect that is bigger than a predefined allowed force is directed to the hatch 2 toward the outside. The breaking sections of the fuses 1 keeping the hatch 24 closed then break and the hatch 24 opens and moves for a distance Lk. The absorbing sections of the fuses receive energy and extend so that a gap 31 is formed between the hatch 24 and frame 25, which is shown in Figure 7a: Through the gap 31 , the overpressure is released together with possible flue gases arid heat.

[0054] Figures 8a and 8b show a passenger cabin 32 of a vehicle; in which a table 33 or some other cabin part is supported to a body 34 with a mechanical fuse 1. The fuse 1 keeps the cabin part firmly in place by means of a breaking section, but allows the cabin part to yield in a controlled manner by means of an absorbing section, when a passenger 35 is thrown against the table 33. The absorbing section remains intact thanks to its structure and thus keeps the table 33 fastened to the body 34. The cabin part that is fastened with the mechanical fuse 1 yields, but does not collapse.

[0055] In some cases, features disclosed in this application may be used as such, regardless of other features. On the other hand, when necessary, features disclosed in this application may be combined in order to provide different combinations.

[0056] The drawings and the related description are only intended to illustrate the idea of the invention. Details of the invention may vary within the scope of the claims.