Fuse, thermal trip device comprising such a fuse, mounting jig for assembling such a fuse and method of mounting such a fuse

Abstract

Fuse, thermal trip device comprising such a fuse, mounting jig for assembling such a fuse and method for assembling such a fuse A fuse (10) for a thermal trip device comprises a bulb (12) containing a liquid and two plates (14A, 14B) each comprising an end for hooking onto the thermal trip device, a sliding portion, an escape portion and a retaining end having two retaining tabs. When the fuse is assembled, the bulb extends between the retaining ends of the two plates by being received in receiving members of the retaining ends of the two plates. In addition, the sliding portion of each plate is located between the two retaining tabs of the other plate.The second plate is movable in translation relative to the first plate, along an axis parallel to the sliding portions of the plates, the bulb blocking a translation of the second plate in a direction of approaching the retaining end of the second plate relative to the retaining end of the first plate. Figure for the abstract: 2.

Description

Title of the invention: Fuse, thermal trip device comprising such a fuse, mounting jig for assembling such a fuse and method for mounting such a fuse

[0001] The present invention relates to a fuse for a thermal trip device, a thermal trip device comprising such a fuse, a mounting jig for assembling such a fuse and a method of mounting such a fuse.

[0002] In the field of fire detection devices, it is known to use a thermal trigger provided with a fuse to detect the occurrence of a fire and to trigger fire-fighting means automatically when a fire is detected.

[0003] A wide variety of thermal triggers exist.

[0004] For example, it is known to use a fixed automatic water extinguishing installation, also called a sprinkler, which comprises extinguishing heads connected to water pipes. Each extinguishing head comprises a bulb which is compressed between a valve closing a water pipe and a retaining element. This compression is caused by the water pressure contained in the pipe, which presses on the valve and thus on the bulb. A rise in temperature of the bulb above a predetermined threshold causes it to rupture, which releases the valve and opens the water pipe, allowing watering to be triggered.

[0005] The use of such bulbs is particularly effective, because it is simple and inexpensive. However, such bulbs are particularly suitable for operating in compression, that is to say to prevent the coming together of two parts, such as the valve and the retaining element in the case of a sprinkler, but are not intended to operate in traction, that is to say to prevent the moving apart of two parts.

[0006] To address this limitation, US 5,927,890 A proposes a fuse comprising a bulb held between two joining pieces. Each joining piece has a hooking eyelet from which two tabs extend, each tab surrounding one of the two ends of the bulb. The two joining pieces are hooked to each other. When a tensile force is exerted on the fuse via the two eyelet hooks, the bulb is compressed between the tabs of the two joining pieces, which prevents the two pieces from being released. When the bulb bursts, under the effect of high heat, the tensile force exerted on the fuse causes the two joining pieces to separate. This fuse therefore makes it possible to use a bulb in a fuse operating in traction, but has a technical limit to a significant tensile force. Indeed, too much tensile force exerted on the fuse can cause it to break, either by bursting the bulb or by deformation of the connecting parts. Such an untimely rupture risks triggering a fire-fighting system in the absence of a fire.

[0007] FR-A-3 052 362 A proposes another fuse to address this limitation. This fuse comprises a bulb, two stressed stirrups and a free-moving part. Each of the two stirrups has an eyelet for exerting a tensile force on the fuse and, when the fuse is assembled, the relative movement of the two stirrups is prevented by the free-moving part, which is blocked by the bulb and by shafts connected to each of the two stirrups. Although more robust than the fuse of US 5,927,890 A, this fuse has several disadvantages: when it is triggered, the free-moving part is ejected from the fuse and can therefore strike people or equipment located nearby, which is dangerous. In addition, this fuse requires the use of a large number of parts and is complex; its manufacture is therefore expensive.In addition, the fuse forms a cage surrounding the bulb, so that after the bulb breaks, fragments of the bulb can block the relative movement of the two brackets and prevent the triggering of a device connected to the fuse. Finally, this fuse is not suitable for use in an aggressive environment, because the two brackets and the freely moving part have significant contact surfaces between them, increasing the risk of corrosion and blocking of these parts together.

[0008] It is these drawbacks that the invention more particularly intends to remedy, by proposing a fuse operating in traction and using a bulb, which is at the same time robust, reliable and inexpensive.

[0009] For this purpose, the invention relates to a fuse for a thermal trigger, comprising: - a ampoule containing a liquid, having a first end and a second end, the ampoule being configured to break when the liquid contained in the ampoule reaches a predetermined temperature, - a first plate and a second plate.

[0010] According to the invention, each of the first and second plates comprises: • a hooking end, configured to allow the plate to be hooked to a hooking element of a thermal trigger; • a sliding portion, connected to the hooking end and having a planar shape extending along a sliding axis; • an exhaust portion, connected to the sliding portion; and • a retaining end, connected to the exhaust portion and comprising a receiving member and two retaining tabs.

[0011] In addition, in the assembled configuration of the fuse: - the bulb extends between the retaining end of the first wafer and the retaining end of the second wafer; - the receiving member of the retaining end of the first plate receives the first end of the bulb; - the receiving member of the retaining end of the second plate receives the second end of the bulb; - the sliding portion of the first pad is located between the two retaining tabs of the retaining end of the second pad; - the sliding portion of the second pad is located between the two retaining tabs of the retaining end of the first pad; - the second plate is movable in translation relative to the first plate along a translation axis parallel to the sliding axis of the sliding portion of the first plate and parallel to the sliding axis of the sliding portion of the second plate; and - the bulb blocks a translation of the second plate along the translation axis in a direction of bringing the retaining end of the second plate closer to the retaining end of the first plate.

[0012] Thanks to the invention, the plates exert a tensile force on the bulb, which improves its resistance and prevents accidental triggering of the fuse. In addition, the first and second plates are simple to manufacture, which reduces the manufacturing cost of the fuse, and have small contact surfaces between them, which limits the risks of the plates jamming together. Furthermore, each plate is designed to be attached to a hooking element of the thermal trigger, preventing the ejection of parts when the fuse is triggered. The design of the first and second plates also allows simple and reliable triggering of the fuse.

[0013] According to other advantageous aspects of the invention, the fuse comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0014] - The fuse further comprises a fixing part and, in the assembled configuration of the fuse, the fixing part is fixed to the first plate and blocks a translation of the second plate along the translation axis in a direction of distance of the retaining end of the second plate relative to the retaining end of the first plate.

[0015] - The receiving member of the retaining end of the second plate is a receiving hole and, in the assembled configuration of the fuse, the second end of the bulb extends through the receiving member of the retaining end of the second wafer and passes through the retaining end of the second wafer, and the fastener covers the receiving member of the retaining end of the second wafer and surrounds the second end of the bulb.

[0016] - A distance separating the two retaining tabs of the first plate, measured perpendicular to the sliding axis of the first pad, is less than a width of the sliding portion of the second pad, measured perpendicular to the sliding axis of the second pad and greater than a width of the escape portion of the second pad, measured perpendicular to the sliding axis of the second pad, and a distance separating the two retaining tabs of the second pad, measured perpendicular to the sliding axis of the second pad, is less than a width of the sliding portion of the first pad, measured perpendicular to the sliding axis of the first pad and greater than a width of the escape portion of the first pad, measured perpendicular to the sliding axis of the first pad.

[0017] - Each of the first and second plates further comprises a die portion clearance, located between the escapement portion and the retaining end of the pad, comprising two clearance walls extending along a plane inclined relative to the sliding axis of the pad. A width of the clearance portion of the first pad, measured perpendicular to the sliding axis of the first pad at the clearance walls of the first pad, is greater than the distance separating the two retaining tabs of the second pad, and a width of the clearance portion of the second pad, measured perpendicular to the sliding axis of the second pad at the clearance walls of the second pad, is greater than the distance separating the two retaining tabs of the first pad.

[0018] - For each of the first and second plates, the retaining end has a plane shape and an angle formed between the sliding portion and the retaining end is strictly greater than 90°, preferably between 100° and 110°.

[0019] - For each of the first and second plates, the hooking end has a plane shape and forms an angle with the sliding portion of between 158° and 160°, and in which, preferably, in the assembled configuration of the fuse, the hooking end of the first plate and the hooking end of the second plate extend in the same hooking plane.

[0020] - The first plate is identical to the second plate.

[0021] According to another aspect, the invention also relates to a thermal trigger

[0022]

[0023]

[0024]

[0025]

[0026] including: - a compressed gas cartridge, - a trigger element, configured to strike the compressed gas cartridge when triggered, - a base and - a fuse according to any one of claims 1 to 8, the hooking end of one of the plates among the first plate and the second plate being hooked to the base and the hooking end of the other of the plates among the first plate and the second plate being hooked to the trigger element The fuse is configured to: - prevent the triggering element from triggering when the bulb is intact and - cause the trigger element to trip when the bulb breaks. This thermal trigger induces the same advantages as those mentioned above regarding the fuse of the invention. According to another aspect, the invention also relates to a mounting jig for assembling a fuse as described above, comprising: - holding elements, configured to hold the first plate and the second plate in position on the mounting template while allowing a translation of the first plate along the translation axis aimed at bringing the retaining end of the first plate closer to the retaining end of the second plate; - a bulb holder, configured to receive the bulb and position the bulb between the retaining ends of the first and second pads and between the sliding portions of the first and second pads; and - a protrusion, configured to position the fixing part in contact with the first plate. This mounting template induces the same advantages as those mentioned above regarding the fuse of the invention. According to another aspect, the invention also relates to a method of mounting a fuse as described above using the mounting jig described above, the method comprising at least the following steps: - assembling the first pad with the second pad, by arranging the two retaining tabs of the first pad at the exhaust portion of the second pad and by arranging the two retaining tabs of the second pad at the exhaust portion of the first wafer, then moving the second wafer relative to the first wafer along the translation axis so as to move the retaining end of the second wafer away from the retaining end of the first wafer; - position the first plate and the second plate on the mounting template; - position the bulb on the mounting template, preferably on the bulb holder, by placing the first end of the bulb opposite the receiving member of the retaining end of the first plate and by placing the second end of the bulb opposite the receiving member of the retaining end of the second plate; - moving the first plate relative to the second plate along the translation axis so as to bring the retaining end of the first plate closer to the retaining end of the second plate until the bulb blocks the movement of the first plate; - position the fixing part on the mounting template; and - fix the fixing piece to the first plate.

[0027] This mounting method induces the same advantages as those mentioned above regarding the fuse of the invention.

[0028] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which:

[0029] [Fig-1] [Fig. 1] is a partial perspective view of a thermal trigger according to the invention.

[0030] [Fig.2] [Fig.2] is a perspective view of a fuse according to the invention, the fuse belonging to the thermal trigger of [Fig.l].

[0031] [Fig.3] [Fig.3] is an exploded perspective view of the fuse of [Fig.2].

[0032] [Fig.4] [Fig.4] is a top view of a plate belonging to the fuse of the Figures 2 and 3.

[0033] [Fig.5] [Fig.5] is a series of side views of the fuse of figures 2 and 3, illustrating, on several inserts A) to D), several phases of the rupture of the fuse.

[0034] [Fig.6] [Fig.6] is a perspective view of a mounting jig according to the invention.

[0035] [Fig.7] [Fig.7] is a perspective view of the mounting jig of [Fig.6], on which the fuse of Figures 2 and 3 is mounted.

[0036] A thermal trigger 1, also called a pneumatic thermal trigger, is visible in [Fig.l]. The thermal trigger 1 comprises a base 2, which has a hook 3. The base 2 also allows the thermal trigger 1 to be fixed on an unrepresented support.

[0037] The thermal trigger further comprises a compressed gas cartridge 4, as well as a triggering element 5. Here, the triggering element 5 comprises a support piece 6, which is fixed relative to the base 2, a piston 7, which is movable relative to the support piece 6 and a spring 8. The compressed gas cartridge is connected to an outlet connection 9, intended to be connected to a pneumatic circuit. In the state shown in [Fig.l], the compressed gas cartridge is sealed. The expansion of the gas contained therein and its flow towards the outlet connection 9 are prevented.

[0038] In [Fig.l], the support piece 6 and the base 2 are partially torn away to reveal the piston 7 and the spring 8, which are normally hidden, being arranged inside the support piece 6.

[0039] The thermal trigger further comprises a bulb fuse 10. The fuse 10 is fixed on the one hand to the hook 3 and on the other hand to the piston 7. The spring 8 exerts an elastic force on the piston 7 which aims to move the piston 7 away from the hook 3, in the direction of the compressed gas cartridge 4. The presence of the fuse 10 prevents this movement of the piston. In other words, the fuse 10 makes it possible to keep the piston 7 in position, against the force exerted by the spring 8, that is to say it prevents the triggering element 5 from being triggered. The fuse 10 is thus subjected to a tensile force, between the hook 3 and the piston 7.

[0040] The fuse 10 is designed to no longer hold the piston 7 when it reaches a predetermined temperature, as explained in more detail below. When this predetermined temperature is reached, the fuse 10 breaks and the piston 7 is then set in motion by the spring 8. It then strikes the compressed gas cartridge 4, breaking its seal and allowing the expansion and flow of the gas contained therein towards the outlet connection 9. It is then said that the triggering element 5 has been triggered, this triggering being caused by the fuse 10. Thus, the fuse reaching the predetermined temperature causes the triggering element 5 to trigger, the opening of the compressed gas cartridge 4 and the supply of the pneumatic circuit with the gas from the compressed gas cartridge.

[0041] The thermal trigger 1 can be used in various fire-fighting installations to, on the one hand, detect the start of a fire and, on the other hand, activate fire-fighting means.

[0042] For example, the thermal trigger may be integrated into an automatic extinguishing device, in which, after triggering the thermal trigger, the gas contained in the compressed gas cartridge 4 is used to enable the pressurization of an extinguishing agent contained in a tank. This type of automatic extinguishing device is commonly used in fuel distribution areas, to extinguish any fire outbreak without requiring human intervention.

[0043] Fuse 10 will now be described in more detail with reference to FIGS. 2 to 5.

[0044] The fuse 10 comprises a bulb 12 having a first end 12A and a second end 12B and extending along a bulb axis XI2. As best seen in [Fig.3], the first end 12A of the bulb has a rounded shape, for example a half-sphere, while the second end 12B of the bulb has a refined shape, for example a point. The bulb contains a liquid, for example alcohol, and is configured to break when this liquid reaches a predetermined temperature. In practice, as the temperature rises, the liquid expands and exerts pressure on the bulb, causing the bulb to rupture.

[0045] The predetermined temperature is, for example, set at 68°C. Alternatively, this temperature may be different, generally being set at a value between +57°C and 260°C.

[0046] The fuse 10 comprises a first plate 14A and a second plate 14B.

[0047] The first plate 14A comprises a hooking end 16A, which is, in the example, plane. The hooking end 16A includes a hooking hole 18A, which allows the first plate 14A to be fixed to the thermal trigger 1 and a fixing hole 20A.

[0048] The first plate 14A comprises a sliding portion 22A, which is adjacent, i.e. connected, to the hooking end 16A. The sliding portion 22A has a planar shape extending along a sliding axis X22A. Advantageously, the sliding portion 22A has a rectangular shape, extending over a length L22 preferably between 9.45 mm and 9.85 mm, measured parallel to the sliding axis X22A and over a width / 22 preferably between 12.80 mm and 13.20 mm, measured perpendicular to the sliding axis X22A.

[0049] Advantageously, the hooking end 16A is inclined relative to the sliding portion 22A, that is to say that the hooking end forms an angle [3 with the sliding portion. The angle [3 is preferably between 158° and 160°.

[0050] The first plate 14A comprises an exhaust portion 24A, which is adjacent, i.e. connected, to the sliding portion 22A. The exhaust portion 24A has a planar shape extending along the sliding axis X22A. In other words, the exhaust portion extends in the continuity of the sliding portion. Advantageously, the exhaust portion 24A has a rectangular shape, extending over a length L24 preferably between 3.30 mm and 3.39 mm, measured parallel to the sliding axis X22A and over a width / 24 preferably between 8.62 mm and 8.65 mm, measured perpendicular to the sliding axis X22A.

[0051] The first plate 14A comprises a clearance portion 26A, which is adjacent, i.e. connected, to the exhaust portion 24A. The clearance portion has a planar shape extending along the sliding axis X22A. In other words, the clearance portion extends in continuity with the sliding and exhaust portions.

[0052] The first plate 14A comprises two clearance walls 28A, which extend from the clearance portion 26A along an inclined plane P28A relative to the sliding axis X22A of the first plate, i.e. the clearance walls 28A form an angle θ with the clearance portion 26A. The angle θ is preferably between 108° and 110°.

[0053] In practice, the two clearance walls 28A are formed at the end of the clearance portion 26A connected to the exhaust portion 24A, on either side of the clearance portion.

[0054] Advantageously, the clearance portion 26A has a rectangular shape, extending over a length L26 preferably between 8.40 mm and 8.60 mm, measured parallel to the sliding axis X22A and over a width / 26 preferably between 18.80 mm and 19.20 mm, measured perpendicular to the sliding axis X22A at the clearance walls 28A.

[0055] The first plate 14A comprises a retaining end 30A, which is adjacent, i.e. connected, to the clearance portion 26A. The retaining end 30A has a planar shape. Advantageously, the retaining end 30A has a rectangular shape, extending over a length L30 preferably between 14.10 mm and 14.40 mm and over a width / 30 preferably between 18.7 mm and 19.30 mm.

[0056] The retaining end 30A is inclined relative to the clearance portion 28A, i.e. the retaining end forms an angle α with the clearance portion. The angle α is strictly greater than 90° and is preferably between 100° and 110°.

[0057] The retaining end 30A comprises a receiving member 32A, which in the example is a receiving hole and two retaining tabs 34A. The two retaining tabs 34A are, in practice, formed at the free end of the retaining end 30A, that is to say opposite the clearance portion 26A and are spaced apart by a width / 34 preferably between 9.00 mm and 9.20 mm. The two retaining tabs 34A form between them a retaining volume 36A of width / 36 preferably between 13.30 mm and 13.70 mm. The two retaining tabs 34A have the shape of hooks, so that the width / 36 is greater than the width / 34.

[0058] In addition, the width / 22 of the sliding portion 22A is greater than the width / 34 separating the two retaining tabs 34A and is less than the width / 36 of the retaining volume 34A; the width / 24 of the exhaust portion 24A is less than the width / 34 separating the two retaining tabs 34A and is less than the width / 36 of the retaining volume 34A; and the width / 26 of the clearance portion 26A is greater than the width / 34 separating the two retaining tabs 34A and is less than the width / 36 of the retaining volume 34A. In addition, the width / 24 of the exhaust portion 24A is less than the width / 22 of the sliding portion 22A, itself less than the width / 26 of the clearance portion 26A and the width / 30 of the retaining end 30A. Preferably, the width / 26 of the clearance portion 26A is equal to the width / 30 of the retaining end 30A.

[0059] The second plate 14B comprises a hooking end 16B, with a hooking hole 18B and a fixing hole 20B; a sliding portion 22B extending along a sliding axis X22B; an escape portion 24B; a clearance portion 26B; two clearance walls 28B; a retaining end 30B with a receiving member 32B and two retaining tabs 34B. In practice, the second plate 14B present is similar to the first plate 14A.

[0060] Advantageously, as in the example of the figures, the second plate 14B is identical to the first plate 14A, which facilitates the manufacture of the fuse 10 and reduces its cost. Thus, the dimensions and arrangements of the hooking and retaining ends and of the sliding, escape and release portions of the second plate are identical to those of the first plate.

[0061] The fuse 10 further comprises a fixing part 38, which is in the example “S” shaped. The fixing part 38 comprises a fixing portion 40, which is essentially planar and which has a fixing hole 42, as well as a protection portion 44, which is “C” shaped.

[0062] As seen in [Fig.2], in the assembled configuration of the fuse, the first plate 14A and the second plate 14B are assembled to each other and the bulb 12 is held between the first plate 14A and the second plate 14B.

[0063] More precisely, in the assembled configuration of the fuse: - The sliding axis X22A of the sliding portion 22A of the first plate 14A is parallel to the sliding axis X22B of the sliding portion 22B of the second plate 14B. - The retaining end 30A of the first plate 14A extends parallel to the retaining end 30B of the second plate 14B. - The bulb 12 extends between the retaining end 30A of the first plate 14A and the retaining end 30B of the second plate 14B. - The receiving hole 32A of the retaining end 30A of the first plate 14A receives the first end 12A of the bulb 12. In practice, the receiving hole 32A has a diameter adapted so that the first end 12A of the bulb 12 is partly received in the receiving hole, without being able to pass through the receiving hole. - The receiving hole 32B of the retaining end 30B of the second plate 14B receives the second end 12B of the bulb. In practice, the receiving hole 32A has a diameter adapted so that the second end 12B of the bulb 12 passes through the receiving hole, without allowing the bulb to pass completely through the receiving hole. Thus, the second end of the bulb passes through the retaining end 30B of the second plate 14B. - The sliding portion 22A of the first plate 14A is engaged between the two retaining tabs 34B of the retaining end 30B of the second plate 14B. In other words, the sliding portion 22A is received in the retaining volume 36B and is surrounded by the retaining tabs 34B. - The sliding portion 22B of the second plate 14B is engaged between the two retaining tabs 34A of the retaining end 30A of the first plate 14A. In other words, the sliding portion 22B is received in the retaining volume 36A and is surrounded by the retaining tabs 34A.

[0064] It is understood that, in the assembled configuration of the fuse 10, the first plate 14A and the second plate 14B are nested together, which limits the possible relative movements between the two plates. In practice, a translation of the second plate relative to the first plate perpendicular to the sliding axis X22A, or a rotation of the second plate about the sliding axis X22A, is prevented by the cooperation of shapes between the sliding portion 22B and the retaining tabs 34A. Thus, the second plate 14B is only movable in translation relative to the first plate 14A along the sliding axis X22B. Similarly, the first plate is only movable in translation relative to the second plate along the sliding axis X22A.

[0065] A translation axis X22 of the plates 14A and 14B is defined as an axis parallel to the sliding axis X22A of the sliding portion of the first plate, parallel to the sliding axis X22B of the sliding portion of the second plate and located midway between the axes X22A and X22B.

[0066] Furthermore, in the assembled configuration of the fuse, the bulb 12 blocks a translation of the second plate 14B along the translation axis X22, in a direction of bringing the retaining end 30B of the second plate closer to the retaining end 30A of the first plate, since the bulb extends between the retaining ends of the two plates.

[0067] As seen in [Fig.5], the translation axis X22 forms an angle 0 with the bulb axis X12. The angle 0 is preferably between 10° and 20°. This non- null is particularly advantageous for the positioning of the bulb, because the bulb is perpendicular to the retaining ends 30A, 30B, therefore in an ideal position to resist the compressive forces described below.

[0068] In the assembled configuration of the fuse 10, the fixing part 38 is fixed to the first plate 14A, using a fixing member 46, which is in the example a rivet, which extends into the fixing hole 42 of the fixing part 38 and into the fixing hole 20A of the first plate 14A. Thus, the fixing portion 40 of the fixing part 38 is pressed against the hooking end 16A of the first plate 14A.

[0069] In a variant of the invention not shown, the fixing part 38 is fixed to the first plate 14A using other means, such as for example a screw, glue, or welding.

[0070] Furthermore, in the assembled configuration of the fuse 10, the protective portion 44 of the fixing part 38 covers the receiving hole 32B of the retaining end 30B of the second plate 14B and surrounds the second end 12B of the bulb 12. The second end of the bulb is thus protected from possible impacts, which prevents it from accidentally breaking.

[0071] Furthermore, in the assembled configuration of the fuse 10, the protective part 44 of the fixing part 38 presses on the second plate 14B, so as to block a translation of the second plate along the translation axis X22 in a direction of moving the retaining end 30B of the second plate away from the retaining end 30A of the first plate.

[0072] The fuse 10 is held in the assembled configuration on the one hand by the bulb 12, which prevents the two plates from moving towards each other and on the other hand by the fixing part 38, which prevents the two plates from moving away from each other. Thus, untimely disassembly of the fuse is impossible.

[0073] Advantageously, in the assembled configuration of the fuse 10, the hooking end 16A of the first plate 14A and the hooking end 16B of the second plate 14B extend in the same hooking plane P10, which forms an angle y with the translation axis X22. The angle y is preferably between 20° and 22°.

[0074] As seen in [Fig.5], the sum of angles y and [3 is equal to 180°.

[0075] We note co the angle formed by the clearance wall 28A and the plane P10. This angle co is equal to the sum of angles o and y.

[0076] When the thermal trigger 1 is in the assembled configuration, the hook 3 is fixed to the hooking hole 18A of the hooking end 16A of the first plate 14A and the piston 7 is fixed to the hooking hole 18B of the hooking end 16B of the second plate 14B. In the example, the end of the piston 7 has a slot receiving the hooking end 16B and a pin 72 passes through the end of the piston and the hooking hole 18B to allow the piston 7 to be fixed on the hooking hole 18B.

[0077] The fuse 10 is thus kept under tension due to the force exerted by the spring 8 on the piston 7. Two forces F, visible in [Fig. 5], are therefore applied to the hooking ends of the two plates, which are opposite and oriented along a traction axis X10 connecting the two hooking ends. Thus, the traction axis X10 is contained in the hooking plane P10 and the angle co is the angle between the clearance wall 28A and the axis X10 and between the clearance wall 28B and the axis X10. These forces F are transmitted by the plates 14A, 14B to the bulb 12. The geometry of the plates 14A, 14B and more particularly the fact that the bulb is retained between the two retaining ends 30A, 30B of the plates, leads the bulb 12 to be subjected to compressive forces.In other words, the fuse plates make it possible to transform the tensile forces F applied to the hooking ends 16A, 16B of the plates into compressive forces applied to the bulb. Since the bulb 12 is, in a manner known per se, specifically designed to withstand significant compressive forces, the resistance of the fuse 10 to involuntary triggering, linked to a mechanical breakage of the bulb 12, is minimized.

[0078] With reference to [Fig. 5], the process of breaking the fuse 10 is now described. This breaking process begins with the breaking of the bulb 10, illustrated in insert A) of [Fig. 5]. In this phase, the plates 14A, 14B are in an initial position. This breaking occurs when the temperature of the bulb 12 reaches the predetermined temperature, for example set at 68°C.

[0079] After the bulb 12 breaks, the translational movement of the second plate 14B along the translation axis X22, bringing the retaining end 30B of the second plate closer to the retaining end 30A of the first plate 14A, is no longer blocked by the bulb. In other words, after the bulb breaks, a relative movement of the two plates is possible. This movement leads to the triggering of the fuse 10 and the setting in motion of the piston 7 under the force exerted by the spring 8.

[0080] In a first phase of relative movement of the plates 14A, 14B, the second plate 14B performs a translation movement relative to the first plate 14A along the translation axis X22, from the initial position shown in insert A) of [Fig. 5], to a stop position shown in insert B) of [Fig. 5]. Thanks to the angle y formed between the traction axis X10 and the translation axis X22, the translation of the second plate along the translation axis X22 is efficiently driven by the traction forces F.

[0081] In this stop position, the retaining end 30B of the second plate is in contact, in other words in abutment, with the clearance walls 28A of the first plate and the retaining end 30A of the first plate is in contact, in other words in abutment, with the clearance walls 28B of the second plate. This contact between the retaining ends and the clearance walls prevents the continuation of the translational movement of the second plate relative to the first plate, parallel to the translation axis X22.

[0082] In the stop position, the retaining tabs 34A of the first plate 14A are located at the exhaust portion 24B of the second plate 14B and the retaining tabs 34B of the second plate are located at the exhaust portion 24A of the first plate. Since the width / 24 of the exhaust portions 24A and 24B is less than the distance / 34 separating the two retaining tabs of each of the two plates, a separation, in other words a disassembly, of the two plates is possible. Thus, in the stop position shown in insert B) of [Fig.5], the two plates are not restricted to a relative translational movement.

[0083] In a second phase of relative movement of the plates 14A, 14B, the two plates are separated from each other. This separation is caused by the tensile forces F, which tend to bring the retaining ends 30A, 30B of the two plates closer to each other and by the contact between the retaining end 30A, 30B of each plate with the clearance walls 28A, 28B of the other plate, which allows a release of the retaining tabs of each plate. More precisely, thanks to the angle co formed between the traction axis X10 and the inclined planes P28A, P28B, the tensile forces F cause the plates 14A, 14B to move away from each other by sliding relative to each other in a direction parallel to the inclined planes P28A, P28B.

[0084] Advantageously, the angle a is less than the angle o. This choice of the angles a and a is particularly advantageous for facilitating the separation of the two plates and more precisely the sliding of the walls of the retaining ends 30A, 30B respectively against the clearance walls 28B, 28A. Indeed, the fact that the angle a is less than the angle o reduces the risk of the retaining ends becoming blocked against the clearance walls.

[0085] At the end of this second phase of movement, not shown in [Fig.5], the two plates are no longer interlocked with each other. In other words, the two plates are no longer attached to each other, even if they are still in contact.

[0086] The inclination of the traction axis X10 with the translation axis X22, corresponding to angle y, on the one hand, and the inclination of the traction axis X10 with the clearance walls 28A, 28B, corresponding to the angle of co, on the other hand, is particularly useful for enabling the first and second phases of movements to be carried out. These inclinations make it possible to obtain several movements carried by different directions, namely the translation axis for the first phase and the inclined planes of the clearance walls for the second phase, from the forces F exerted along the traction axis X10.

[0087] In a third phase of relative movement of the pads 14A, 14B, the second pad 14B is driven by the force F applied to it in a translational movement along the traction axis X10 aimed at bringing the retaining ends 30A, 30B of the two pads closer together. It is noted that this force F is caused by the spring 8, which causes a movement of the piston 7 and therefore of the second pad 14B which is attached to the piston.

[0088] This third phase of relative movement of the plates 14A, 14B ends when the retaining ends 30A, 30B of the two plates come into contact. This position is illustrated in insert C) of [Fig.5].

[0089] In a fourth phase of relative movement of the plates 14A, 14B, the retaining end 30B of the second plate 14B slides relative to the retaining end 30A of the first plate 14A, until reaching a position where the two plates are no longer in contact, as illustrated in insert D) of [Fig.5].

[0090] This sliding is facilitated by the angle α formed between the retaining ends 30A, 30B and the release portions 26A, 26B and the sliding portions 22A, 22B of the plates and more particularly by the sum of the angles α and γ, which allows the force F applied to the second plate to easily slide the two retaining ends relative to each other.

[0091] At the end of the fourth phase of movement, the two plates are released from each other, that is to say they are no longer in contact with each other and the movement of the piston 7, driven by the spring 8, is no longer impacted by the fuse 10. The piston 7 can thus strike the compressed gas cartridge 4.

[0092] During the triggering of the fuse, the first plate 14A remains attached to the hook 3 and the second plate 14B remains attached to the piston 7. Thus, apart from the fragments of the bulb 12, no part or debris is ejected or released when the fuse 10 is triggered. This is particularly advantageous to avoid any risk of injury to an operator or damage to an object located near the fuse 10 at the time of its triggering.

[0093] Furthermore, thanks to the first and second plates 14A, 14B which have the shape of folded sheets and which do not form a cage around the bulb 12, the fragments of the bulb are easily expelled from the fuse 10 at the moment of rupture of the bulb. This makes it possible to prevent fragments of the bulb from remaining stuck between the two plates and preventing the release of the two plates. The de- triggering of fuse 10 is thus made more reliable and the risk of blockage is minimized.

[0094] A mounting jig 50 is now described with reference to FIGS. 6 and 7 to facilitate the mounting of the fuse 10. In [Fig. 6], the mounting jig is shown alone and in [Fig. 7], the fuse 10 is shown in the assembled configuration on the mounting jig.

[0095] The mounting template 50 comprises a flat base 52.

[0096] The mounting template comprises two studs 54A, 54B, which extend from the flat base and which form between them a groove 54C. The groove 54C is provided to receive the hooking end 16B of the second plate.

[0097] The mounting jig 50 also includes a platform 56A and a pad 56B, which extend from the flat base 52 and which form between them a groove 56C. The groove 56C is provided to receive the retaining end 30B of the second wafer.

[0098] Thus, thanks to the grooves 54C and 56C, when the second plate 14B is arranged on the mounting template, the positioning of the second plate is controlled and its movement in the plane of the flat base 52 is prevented.

[0099] The mounting jig 50 further comprises a stop 58, which extends from the flat base 52. When the first and second plates 14A, 14B are assembled together and placed on the mounting jig 50, the clearance portion 26A of the first plate 14A bears against the stop 58, facilitating the holding in position of the first plate on the mounting jig 50.

[0100] The mounting jig 50 further comprises a bulb holder 60, which extends from the flat base 52 and which has a groove 62. When the two plates 14A, 14B are assembled together and placed on the mounting jig 50, the bulb holder 60 is located between the retaining ends 30A, 30B of the plates and between the sliding portions 22A, 22B of the plates and the groove 62 extends between the retaining ends of the two plates. In practice, the groove 62 is provided to receive and position the bulb 12 relative to the plates 14A, 14B.

[0101] The mounting jig 50 further includes a protrusion 64, which extends from the platform 56A and which allows the fixing part 38 to be positioned on the mounting jig 50, as described below.

[0102] Preferably, the platform 56A also has a drilling 66, which makes it easier to fix the fixing part 38 on the first plate, as explained below.

[0103] Preferably, the mounting template 50 comprises fixing holes 68, which allow it to be fixed to a work surface (not shown).

[0104] Advantageously, during assembly of the fuse 10, the release portion 26B of the second plate 14B also bears against the protrusion 64 of the platform 56A, facilitating the holding in position of the second plate.

[0105] A method of mounting the fuse 10 using the mounting jig 50 is now described.

[0106] The assembly method comprises a first step consisting of assembling the first wafer 14A with the second wafer 14B, by arranging the two retaining tabs 34A of the first wafer at the exhaust portion 24B of the second wafer and by arranging the two retaining tabs 34B of the second wafer at the exhaust portion 24A of the first wafer, then by moving the second wafer relative to the first wafer along the translation axis X22 so as to move the retaining end 30B of the second wafer away from the retaining end 30A of the first wafer.

[0107] Preferably, this first step is carried out without the aid of the mounting template 50. In practice, this first step is carried out manually by an operator, the nesting of the two plates with each other being facilitated by the geometry of the plates.

[0108] The mounting method comprises a second step, which consists of positioning the first wafer 14A and the second wafer 14B, assembled to each other, on the mounting jig 50. Keeping the wafers in position on the mounting jig is facilitated by the grooves 54C, 56C as well as by the stop 58 and the protrusion 64, which thus form elements for holding the wafers on the mounting jig. The placement of these holding elements is further provided to allow a translation of the first wafer 14A along the translation axis X22 aimed at bringing the retaining end 30A of the first wafer closer to the retaining end 30B of the second wafer. In particular, it is noted that the hooking end 16A passes above the platform 56A of the mounting jig.

[0109] At the end of this second step, a distance separating the retaining ends 30A, 30B of the two plates is greater than a length L12 of the bulb 12.

[0110] The mounting method comprises a third step, which consists of positioning the bulb 12 on the mounting template 50, more precisely in the groove 62, by arranging the first end 12A of the bulb opposite the receiving member 32A of the retaining end 30A of the first plate and by arranging the second end 12B of the bulb opposite the receiving member 32B of the retaining end 30B of the second plate. The height of the bulb support 60 is advantageously provided to allow this positioning of the bulb opposite the receiving members 32A and 32B.

[0111] The mounting method comprises a fourth step, which consists of moving the first plate 14A relative to the second plate 14B along the translation axis X22 so as to bring the retaining end 30A closer to the first plate of the retaining end 30B of the second plate until the bulb 12 blocks the movement of the first plate. At the end of this step, the relative positioning of the two plates 14A, 14B corresponds to the positioning visible in [Fig.2] and on the insert A) of [Fig.5].

[0112] The mounting method comprises a fifth step, which consists of positioning the fixing part 38 on the mounting template 50, between the hooking end 16A of the first plate, the retaining end 30B of the second plate and the protrusion 64 of the mounting template. The protrusion 64 thus makes it possible to position the fixing part 38 in contact with the hooking end 16A of the first plate 14A. The positioning of the fixing part 38 is thus controlled. Furthermore, at the end of this positioning, the fixing hole 42 of the fixing part 38 is opposite the fixing hole 20A of the first plate 14A.

[0113] The assembly method comprises a sixth step, which consists of fixing the fixing part 38 to the first plate 14A. In the example, this fixing is carried out using the rivet 46, which is a blind rivet. For this, the rivet is inserted through the fixing holes 42 and 20A and the rivet is placed using a riveting pliers. Advantageously, to facilitate this riveting, the shank of an unused blind rivet can be inserted into the bore 66, which makes it possible to hold the fixing part 38 in position during the riveting operation.

[0114] At the end of this sixth step, the fuse 10 is assembled and cannot be disassembled without breaking the bulb 12 or without destroying the rivet 46, since the bulb and the fixing part 38 together make it possible to block any translation of the two plates 14A, 14B aimed at moving the two retaining ends 30A, 30B of the plates away from or towards each other.

[0115] The mounting of the fuse 10 described in the above method is facilitated by the use of the mounting jig 50, but this mounting jig is not obligatory for carrying out the mounting of the fuse. Indeed, this mounting can also be carried out manually, or using other mounting devices not described.

[0116] Furthermore, it is also possible to automate the assembly of the fuse 10 using or not the assembly jig 50. For example, a semi-automatic assembly station is produced using the assembly jig 50 to industrialize the assembly of fuses 10. Such a semi-automatic assembly station is preferably completed with an engraving station, allowing the engraving of batch numbers on the fuses 10 for traceability, and a unit control station by industrial vision camera, allowing the performance of a quality control validating the correct assembly of the fuses 10.

[0117] In the example, the first plate 14A and the second plate 14B are each manufactured from a flat sheet, which is stamped to form the walls of clearance 26A, 26B and which is bent to form the angles a and [3. Thus, the first and second plates are particularly simple and inexpensive to manufacture, which reduces the cost of the fuse 10.

[0118] In a variant of the invention not shown, the first plate 14A is not fixed to the base 2 by a hook, but by other means, such as for example by a pin or by a bolt.

[0119] In a variant of the invention that is not shown, the first plate 14A and the second plate 14B are not identical. For example, the second plate 14B does not have a fixing hole 20B, or the attachment ends 16A, 16B of the two plates are different. For example, the attachment ends of the two plates may have different lengths and geometries or may have different attachment means to the base 2 and to the piston 7.

[0120] Any feature described for one embodiment or variation in the foregoing may be implemented for the other embodiments and variations described above, as long as technically feasible.

Claims

Claims

1. Fuse (10) for thermal trip device (1), comprising: - a ampoule (12) containing a liquid, having a first end (12A) and a second end (12B), the ampoule being configured to break when the liquid contained in the ampoule reaches a predetermined temperature, - a first plate (14A) and a second plate (14B), characterized in that each of the first and second plates (14A, 14B) comprises: • a hooking end (16A, 16B), configured to allow the hooking of the plate (14A, 14B) to a hooking element (3, 5) of a thermal trigger (1); • a sliding portion (22A, 22B), connected to the hooking end and having a planar shape extending along a sliding axis (X22A, X22B); • an exhaust portion (24A, 24B), connected to the sliding portion; and • a retaining end (30A, 30B), connected to the exhaust portion and comprising a receiving member (32A, 32B) and two retaining tabs (34A, 34B), and in that, in the assembled configuration of the fuse (10): - the bulb (12) extends between the retaining end (30A) of the first plate (14A) and the retaining end (30B) of the second plate (14B); - the receiving member (32A) of the retaining end (30A) of the first plate (14A) receives the first end (12A) of the bulb (12); - the receiving member (32B) of the retaining end (30B) of the second plate (14B) receives the second end (12B) of the bulb; - the sliding portion (22A) of the first plate (14A) is located between the two retaining tabs (34B) of the retaining end (30B) of the second plate (14B); the sliding portion (22B) of the second pad (14B) is located between the two retaining tabs (34A) of the retaining end (30A) of the first pad (14A); the second plate (14B) is movable in translation relative to the first plate (14A) along a translation axis (X22) parallel to the sliding axis (X22A) of the sliding portion of the first plate and parallel to the sliding axis (X22B) of the sliding portion of the second plate; and the bulb (12) blocks a translation of the second plate (14B) along the translation axis (X22) in a direction of bringing the retaining end (30B) of the second plate closer to the retaining end (30A) of the first plate.

2. Fuse (10) according to claim 1, further comprising a fixing part (38), wherein, in the assembled configuration of the fuse (10), the fixing part (38) is fixed to the first plate (14A) and blocks a translation of the second plate (14B) along the translation axis (X22) in a direction of distance of the retaining end (30B) of the second plate relative to the retaining end (30A) of the first plate.

3. Fuse (10) according to claim 2, wherein the receiving member (32B) of the retaining end (30B) of the second plate (14B) is a receiving hole and wherein, in the assembled configuration of the fuse (10): - the second end (12B) of the bulb (12) extends through the receiving member (32B) of the retaining end of the second plate and passes through the retaining end of the second plate; and - the fixing part (38) covers the receiving member (32B) of the retaining end of the second plate and surrounds the second end of the bulb.

4. Fuse (10) according to one of claims 1 to 3, in which a distance (£34) separating the two retaining tabs (34A) from the first pad (14A), measured perpendicular to the sliding axis (X22A) of the first pad, is less than a width (£22) of the sliding portion (22B) of the second pad (14B), measured perpendicular to the sliding axis (X22B) of the second pad and greater than a width (£24) of the escape portion (24B) of the second pad, measured perpendicular to the sliding axis of the second pad, and wherein a distance (£34) separating the two retaining tabs (34B) of the second pad (14B), measured perpendicular to the sliding axis (X22B) of the second pad, is less than a width (£22) of the sliding portion (22A) of the first pad (14A), measured perpendicular to the sliding axis (X22A) of the first pad and greater than a width (£24) of the escape portion exhaust (24A) of the first pad, measured perpendicular to the sliding axis of the first pad.

5. The fuse (10) of claim 4, wherein each of the first and second pads (14A, 14B) further comprises a clearance portion (26A, 26B), located between the exhaust portion (24A, 24B) and the retaining end (30A, 30B) of the pad, comprising two clearance walls (28A, 28B) extending along an inclined plane (P28A, P28B) relative to the sliding axis (X22A, X22B) of the pad, wherein a width (Σ26) of the clearance portion (26A) of the first pad (14A), measured perpendicular to the sliding axis (X22A) of the first pad at the clearance walls (28A) of the first pad, is greater than the distance (Σ34) separating the two retaining tabs (34B) of the second plate (14B), and wherein a width (£26) of the clearance portion (26B) of the second plate (14B),measured perpendicular to the sliding axis (X22B) of the second plate at the clearance walls (28A) of the second plate, is greater than the distance (£34) separating the two retaining tabs (34A) of the first plate (14A).,

6. Fuse (10) according to one of claims 1 to 5, wherein, for each of the first and second plates (14A, 14B), the retaining end (30A, 30B) has a planar shape and an angle (a) formed between the sliding portion (22A, 22B) and the retaining end is

7.

8.

9.

10. strictly greater than 90°, preferably between 100° and 110°. Fuse (10) according to one of claims 1 to 6, wherein, for each of the first and second plates (14A, 14B), the hooking end (16A, 16B) has a planar shape and forms an angle (|3) with the sliding portion (22A, 22B) between 158° and 160°, and wherein, preferably, in the assembled configuration of the fuse, the hooking end (16A) of the first plate (14A) and the hooking end (16B) of the second plate (14B) extend in the same hooking plane (P 10). Fuse (10) according to one of claims 1 to 7, in which the first plate (14A) is identical to the second plate (14B). Thermal trigger (1) comprising: - a compressed gas cartridge (4), - a trigger element (5), configured to strike the compressed gas cartridge (4) when triggered, - a base (2) and - a fuse (10) according to any one of claims 1 to 8, the hooking end (16A, 16B) of one of the plates (14A, 14B) among the first plate (14A) and the second plate (14B) being hooked to the base (2) and the hooking end of the other of the plates among the first plate and the second plate being hooked to the trigger element (5), wherein the fuse (10) is configured to: - prevent the triggering element (5) from triggering when the bulb (12) is intact and - cause the trigger element (5) to trigger when the bulb (12) breaks. A mounting jig (50) for assembling a fuse (10) according to claim 2, comprising: - holding elements (54C, 56C, 58, 64), configured to hold the first plate (14A) and the second plate (14B) in position on the mounting template (50) while allowing translation of the first plate according to the translation axis (X22) aimed at bringing the retaining end (30A) of the first plate closer to the retaining end (30B) of the second plate; - a bulb holder (60), configured to receive the bulb (12) and position the bulb between the retaining ends (30A, 30B) of the first and second pads (14A, 14B) and between the sliding portions (22A, 22B) of the first and second pads; and - a protrusion (64), configured to position the fixing part (38) in contact with the first plate (14A).

11. A method of mounting a fuse (10) according to one of claims 2 and 3, using the mounting jig (50) of claim 10, comprising at least the following steps: - assembling the first plate (14A) with the second plate (14B), by arranging the two retaining tabs (34A) of the first plate at the exhaust portion (24B) of the second plate and by arranging the two retaining tabs (34B) of the second plate at the exhaust portion (24A) of the first plate, then by moving the second plate relative to the first plate along the translation axis (X22) so as to move the retaining end (30B) of the second plate away from the retaining end (30A) of the first plate; - position the first plate (14A) and the second plate (14B) on the mounting template (50); - positioning the bulb (12) on the mounting template, preferably on the bulb holder (60), by placing the first end (12A) of the bulb opposite the receiving member (32A) of the retaining end (30A) of the first plate and by placing the second end (12B) of the bulb opposite the receiving member (32B) of the retaining end (30B) of the second plate; - move the first plate (14A) relative to the second plate (14B) along the translation axis (X22) so as to bring the retaining end (30A) closer to the first retaining end plate (30B) of the second plate until the bulb (12) blocks the movement of the first plate; position the fixing part (38) on the mounting template; and fix the fixing part (38) to the first plate (14A).

Images