WO2005058086A1

WO2005058086A1 - Release device

Info

Publication number: WO2005058086A1
Application number: PCT/SE2004/001885
Authority: WO
Inventors: Malte Johansson
Original assignee: Malte Johansson
Priority date: 2003-12-18
Filing date: 2004-12-16
Publication date: 2005-06-30
Also published as: SE526698C2; SE0303405D0; SE0303405L

Abstract

The present invention relates to a release device of a strap/a belt, especially in connection with a buckle to a safety helmet, a harness or a safety belt, said device comprising a fastening element (1) and a yieldable hydraulic system (5), and that one end of the strap/the belt is connected to the fastening element (1). It is significant of the device according to the present invention that the device comprises an snap element (3) that is connected to the other end of the strap/the belt, that the snap element (3) in the initial position of the release device is detachably connected to the fastening element (1), that the snap element (3) has a least one flexible means (17) that is part of the detachable connection, and that the flexible means (17) and the hydraulic system (5) are arranged to cooperate with each other.

Description

RELEASE DEVICE

Technical Field of the Invention The present invention relates to a release device of a strap/a belt, especially in connection with a buckle of a safety helmet, a harness or a safety belt, said device comprising a fastening element and a yieldable hydraulic system, and that one end of the strap/the belt is connected to the fastening element.

Background of the Invention Bicycle helmets of today do expose primarily children to a great danger. The buckets are properly fastened when they bike, this being important, but said buckets are extremely difficult to release for a child in an emergency situation. The structural design has caused many hanging accidents when children have been playing wearing their bicycle helmet. Since the helmet is larger than their head they run a risk that the helmet fastens with the child hanging in the helmet with the strap around the neck and without any possibility to release the buckle. Today there are safety buckets to prevent such hanging accidents. The technique of such a buckle is that it releases at a certain load. This brings about that the helmet may escape from the head when the biking child falls down and hence the child's head is without protection at a second and third bump on the head. This is a common scenario in connection with an accident. This helmet can only be used in an environment that is void of vehicles. At present there exists no helmet that can be used both for playing activities and biking activities. Thus, there is a risk to bike in a helmet intended for playing activities and to play in a helmet intended for biking.

Prior Art From WO 03031239 a release device intended for a safety helmet and a safety belt is previously known, said release device will open after having been subjected to a load for a certain time. Two shaft elements are mutually connected by a hinge and the active pulling force is transferred to a release cylinder. When the release cylinder is subjected to a load it is slowly compressed since the fluid inside the cylinder is bypassing a flow restriction hole and the shaft elements are separating. When the release cylinder has been compressed to a sufficient degree an anchoring element is released from the shaft elements and the system is open. This device is structurally relatively complicated, especially when used in connection with a safety helmet for children. Consequently it is also expensive to manufacture. The device is also sensitive to dirt and physical damage. Besides the mounting is complicated as regards the filling of fluid in the release cylinder. From US-A-4, 815, 177 a buckle for a safety belt is previously known and after a collision said buckle will open when some time has expired. In connection therewith a spring must be released and this takes place when the belt is subjected to an exceptional force, e.g. in connection with a collision. Then a yoke of the buckle will be forced downwards by two main springs and the yoke actuates levers that effect release of the belt at one side of the buckle. In order to prevent this from happening too soon the movement of the yoke is counteracted by a time delay unit that comprises pressurized bellows. It is beyond all doubt that the buckle according to US-A-4, 815, 177 is extremely complicated as regards the structural design and hence expensive to manufacture. Since a large number of components are supposed to interact there is a risk of functional disturbances. From WO 90/09909 a buckle for a safety belt is previously known, said buckle will open after a certain time delay subsequent to a collision. Also this buckle is extremely complicated as regards structural design and also bulky due to its complex design. The user decides whether the automatic release should be activated or not.

Objects and Features of the Invention A primary object of the present invention is to present an inexpensive and robust release device that should prevent hanging accidents in connection with children and simultaneously safe to use in an environment with traffic. A further object of the present invention is that the device should be easy to reset subsequent to a release. At least the primary object of the present invention is realized by means of a release device that has been given the features of the pending independent claim 1. Preferred embodiments of the invention are defined in the dependent claims.

Brief Description of the Drawings The present invention will be described more in detail with reference to the accompanying drawings, where: Figure 1 shows a section through a release device according to a preferred embodiment of the present invention, the release device being in an unloaded condition; Figure 2 shows a section through a fastening element of the release device; Figure 3 shows a perspective view of a snap element being part of the release device according to present invention; Figure 4 shows a section through a hydraulic system that is part of the release device according to the present invention, the hydraulic system being in unloaded condition; Figure 5 shows a section through the hydraulic system according to figure 4, however the hydraulic system being in a loaded condition; and Figure 6 shows a section through the release device according to present invention, the hydraulic system of the release device being in a loaded condition.

Detailed Description of a Preferred Embodiment of the Invention The release device according to the present invention, shown in figure 1, comprises a fastening element 1, a snap element 3 and a hydraulic system 5. In figure 2 a section through the fastening element 1 is shown, said fastening element 1 at one end having a first attachment portion 7 that is equipped with a first hole 9 for attachment of the end of a strap/a belt (not shown) . In the area of the end of the fastening element 1 that is opposite the first attachment portion 7 an internal first recess 10 is provided that is intended to receive a first portion of the snap element 3. In an intermediate portion of the fastening element 1 there is a second recess 11 for receiving a second portion of the snap element 3. In the section shown in figure 2 the second recess 11 has a widened shape compared to the first recess 10. In figure 3 a perspective view of the snap element 3 is shown, said snap element 3 having a second attachment portion 15 at one end that is provided with a second hole 16 for the attachment of a strap/a belt ^' (not shown) . The snap element 3 has two flexible means in the shape of shafts 17, said means projecting from the second attachment portion 15. Enlargements/shoulders 18 are provided in the area of the free ends of the shafts 17, said enlargements/shoulders 18 being located on the sides of the shafts 17 that faces away from each other. The shafts 17 are resilient and will flex towards each other when the snap element 3 is inserted in the first recess 10 of the fastening element 1. On the sides of the shafts 17 that faces towards each other depressions 19 are provided in the shafts 17, said depressions 19 being intended to receive the free ends of the hydraulic system 5. In figure 4 a section through the hydraulic system 5 is shown, said hydraulic system 5 comprising a cylinder 20, a piston 21, a pressure spring 22 and a housing 23 in the shape of a rubber hose. The cylinder 20 and the piston 21 have each one end designed to be received by the depressions 19 of the snap element 3. By this design the ends of the hydraulic system 5 will slide in the depressions 19 when the shafts 17 of the snap element 3 are subjected to angular deformation. In the cylinder 21 a pressure spring 22 is received, said pressure spring 22 resting against a bottom portion 26 of the cylinder 20. On top of the pressure spring 22 a piston 21 is provided. The cylinder 20 has a hole 27 at one end for the purpose of filling the hydraulic system 5 with fluid. The housing 23, in the shape of a rubber hose, is sealed to the external side of the wall of the cylinder 20 and to the external side of the piston 21. The housing 23 surrounds the cylinder 20 and the piston 21. The housing 23 is manufactured from a flexible material, e.g. rubber, and may be glued to the cylinder 20 and the piston 21. There is a gap 31 between the cylinder 20 and the piston 21 and fluid may flow through said gap 31. An incompressible fluid is contained in the housing 23, said fluid filling out the internal space of the cylinder 20. Reference is again made to figure 1, from which it is evident that the snap element 3 is received in the fastening element 1. In connection therewith a first portion of the shafts 17 are received in the first recess 10 while a second portion of the shafts 17, i.e. the portions having the shoulders 18, are received in the second, widened recess 11, said shoulders 18 cooperating with the second recess 11 in order to clamp the snap element 3 in the fastening element 1. The shafts 17 are kept separated by the hydraulic system 5 that is located between the shafts 17. The hydraulic system 5 of the release device according to the present invention functions in the following way, reference being made to figures 5 and 6, the hydraulic system 5 being in a loaded position, where the piston 21 has been forced into the cylinder 20 so far that the snap element 3 is about to be released from the fastening element 1, see especially figure 6. When a force F2 acts on the hydraulic system 5 the cylinder 20 and the piston 21 are compressed. The fluid that is contained in the cylinder 20 is forced through the gap 31 by the pressure from the piston 21, said fluid filling out the housing 23. In order to compress the cylinder 20 and the piston 21 it is required that the force F2 overcomes the spring force of the pressure spring 22. When the force F2 ceases to act on the hydraulic system 5 the pressure spring 22 forces the piston 21 backwards and the fluid flows back to the cylinder 20. By choosing the spring force of the pressure spring 22 the release force may be varied. The force F2 is created by an external force FI, see figure β, that acts upon the release device according to the present invention. This external force FI strives to pull the snap element 3 out of the fastening element 1. By choosing the angle by which the shoulders 18 of the snap element 3 affect the fastening element 1, and choice of material/friction coefficient, the magnitude of the external force FI may vary, still said force FI being necessary to create the force F2. Thus the snap element 3 has a release force, i.e. a force FI that must be acquired to deflect the shafts 17 towards each other, said shafts 17 initiating the force F2 that acts upon the hydraulic system 5. The external force FI arise when the strap/the belt that is connected to the release device according to the present invention is subjected to a strain, e.g. if a child that carries a helmet is hooked up by a rigid object. In connection therewith the external force FI strives to separate the snap element 3 from the fastening element 1, this generating the force F2 that acts upon the hydraulic system 5. When the hydraulic system 5 has been compressed, by the force F2, to a sufficient degree the shoulders 18 of the snap element 3 are released from the fastening element 1, see figure 6, and the snap element 3 may be pulled out of the fastening element 1. If the external force ceases to act before the hydraulic system 5 has been compressed to a sufficient degree in order to release the snap element 3, the pressure force of the shafts 17, together with the spring force of the pressure spring 22, will pull the snap element 3 back into the fastening element 1. If the release device according to the present invention is released and the fastening element 1 and the snap element 3 are separated from each other, the release device is reset to its initial position by having the user to compress, with his/her fingers, the shafts 17 of the snap element 3, and hence the hydraulic system 5, in order to enter the shafts 17 in the fastening element 1. When the shoulders 18 of the shafts 17 reach the second recess 11 they may again expand to their initial position and the snap element 3 is clamped in the fastening element 1. If the strap/the belt that the release device according to present invention is connected to is subjected to an accidental jerk the release device will not release the snap element 3 from the fastening element 1. The reason therefore is that both the spring force of the shafts 17 on the snap element 3, the pressure spring 22 and fluid between the cylinder 20 and the piston 21 strives to counteract the movement of the cylinder 20 and the piston 21 that is initiated by a jerk. In order to achieve a displacement of the cylinder 20 and the piston 21 a permanent force FI is required in the strap/the belt, said permanent force FI initiating a displacement of the cylinder 20 and the piston 21 to make them approach each other. In connection with a permanent force the fluid flows through the gap 31 between the cylinder 20 and piston 21. Thereby, the volume of fluid between the cylinder 20 and the piston 21 decreases and said elements approach each other.

Feasible Modifications of the Invention In the embodiment described above the ends of the hydraulic system 5, i.e. the cylinder 20 and piston 21, are located between the shafts 17 of the snap element 3 (horizontal location) . Within the schoop of the present invention the hydraulic system 5 may be located in the longitudinal direction of the snap element 3 (vertical location) . Another feasible modification is to delete the pressure spring 22 in the hydraulic system 5 and instead the cylinder 20 and piston 21 are connected to the snap element 3, for instance by means of bayonet coupling. By this arrangement the spring force in the shafts 17 of the snap element 31 are used to force the cylinder 20 and the piston 21 back to initial position when the hydraulic system 5 is not subjected to any load. A further feasible alternative embodiment is to have only one flexible means/shaft 17 on the snap element 3 and have the other one fixed. In the embodiment described above the flexible means are mentioned shafts. However, said means may also be mentioned tongues or legs.

Claims

1. Release device of a strap/a belt, especially in connection with a buckle of a safety helmet, a harness or a safety belt, said device comprising a fastening element (1) and a yieldable hydraulic system (5) , and that one end of the strap/the belt is connected to the fastening element (1) , c h a r a t e r i s e d in that the device comprises a snap element (3) that is connected to the other end of the strap/the belt, that the snap element (3) in the initial position of the release device is detachably connected to the fastening element (1), that the snap element (3) has a least one flexible means (17) that is part of the detachable connection, and that the flexible means (17) and the hydraulic system (5) are arranged to cooperate with each other.

2. Release device according to claim 1, c h a r a t e r i s e d in that the snap element (3) has two flexible means in the shape of shafts (17)/ and that the hydraulic system (5) is provided in the space between the shafts (17) .

3. Release device according to claim 1 or 2, c h a r a t e r i s e d in that at least one shaft (17) of the snap element (3) is equipped with a shoulder (18) .

4. Release device according to any of the previous claims, c h a r a t e r i s e d in that the hydraulic system (5) comprises a cylinder (20) , a piston (21) , a housing (23) of flexible material and a fluid that is received inside the housing (23), said fluid being substantially incompressible.

5. Release device according to claim 4, c h a r a t e r i s e d in that there is a fluid passage (31) between the cylinder (20) and the piston.

6. Release device according to claim 4 or 5, c h a r a t e r i s e d in that the hydraulic system (5) comprises means (22) to reset the piston (21) to its initial position.

7. Release device according to claim 6, c h a r a t e r i s e d in that the means for resetting constitutes a pressure spring (22) .

8. Release device according to any of the previous claims, c h a r a t e r i s e d in that the shaft (17) has a depression (19) that is intended to cooperate with one end of the hydraulic system (5) .