Patent Application
20250058685
The disclosure relates to a spring unit, where the spring unit comprises a first attachment arrangement, a second attachment arrangement and a spring arrangement. The spring arrangement comprises a first flexible member attached to and extending between the first attachment arrangement and the second attachment arrangement. The first attachment arrangement is fixedly attached to a support structure and the second attachment arrangement is arranged to move a first distance essentially vertically in response to a load being exerted on the second attachment arrangement. The disclosure also relates to a method for changing a spring constant of a spring arrangement in a spring unit.
In the use of high-speed boats, impacts resulting from traversing waves can be severe due to the increased speed of the boat. Instead of following the contours of the waves, a high-speed boat can lose contact with the wave, resulting in high drops of up to several meters. This creates a need to protect drivers and occupants from impact forces.
Most existing marine suspension seats have severe functional issues making them dangerous. Too forceful impacts can result in suspensions bottoming out. Bottoming out amplifies, instead of mitigating, the impacts on the occupant. Such functional issues increase the risk of severe injuries and overboard ejections which may lead to fatal accidents.
Both rigid seats and most suspension seats have cushions that often amplify rather than mitigate impacts transmitted from the boat to the seated person. Other issues limiting extensive use relate to the heavy weight and large space requirements for suspension mechanisms.
These issues can also arise in various situations on land such as in vehicles travelling over uneven terrain, e.g., rallying or high-speed off-road driving.
DE 43 14 975 C1 discloses a seat frame comprising a base element, a top element and a spring arrangement between the base and top elements comprising at least two leaf springs arranged one above the other at a spacing from each other and at least approximately parallel to each other. Contact or bearing members are provided for the base element 12 or the top element 14.
US 2006/0061021 A1 discloses a spring system comprising flat plate-springs with one end mounted rigidly to an un-sprung first base and the opposite end mounted rigidly to a sprung second base. The spring system is fitted with cams as strain-control surfaces, mounted tangent to the plate springs and spaced progressively from the said plate-springs beginning at the tangency. The strain-control cams are movable to provide for adjustable spring rates, actively repositioned upon demand therein providing an adaptive active spring-rate system or suspension.
US 2016/0143443 A1 discloses a seating arrangement including a base support, a support arrangement movable between upright and reclined positions, and a spring arrangement that includes a first portion attached to the support arrangement, a second portion attached to the base support and an intermediate portion positioned between the first and second positions. First and second members are configured to bias the support arrangement from the reclined position toward the upright position. The second spring member is spaced from the first spring member, and an adjustment member is positioned between the first and intermediate portions, the adjustment member adjustable between positions that adjust the force exerted by the first and second spring on the support arrangement.
Hence, there is a need for an improved suspension with minimum space requirements.
An objective of the disclosure is to provide a spring unit and a method for changing a spring constant of a spring arrangement in a spring unit addressing the issues raised above. The objective is achieved by the seat arrangement of claim 1 and the method of claim 14. Dependent claims provide advantageous example embodiments.
The disclosure relates to a spring unit, where the spring unit comprises a first attachment arrangement, a second attachment arrangement and a spring arrangement. The spring arrangement comprises a first flexible member attached to and extending between the first attachment arrangement and the second attachment arrangement. The first attachment arrangement is fixedly attached to a support structure and the second attachment arrangement is arranged to move a first distance essentially vertically in response to a load being exerted on the second attachment arrangement. The spring arrangement further comprises a first engagement element arranged to cause a change in a spring constant of the first flexible member, such that when the second attachment arrangement has moved a part of the first distance, the first flexible member comes into contact with the first engagement element, leading to that the spring constant of the first flexible member increases.
One advantage with such a spring unit is that can be designed to have a first spring constant in a movement range of the second attachment arrangement caused by small impacts. When larger impacts are experienced leading to that the second attachment arrangement moves a predetermined part of the first distance, leading to contact between the first flexible element and the engagement element, the increase in the spring constant of the first flexible member will increase the force needed to further bend the first flexible member and move the second attachment arrangement. I.e., when the first flexible member comes into contact with the first engagement element, the stiffness of the first flexible member increases. This improves the shock mitigation of the spring unit for larger impacts, reducing or eliminating the risk of bottoming out, while at the same time providing a spring unit that is easy to install and adapt to specific conditions.
A first area of the first flexible member may be fixedly attached to a first area of the first attachment arrangement. The first engagement element is arranged at a second distance from the first area of the first attachment arrangement in a longitudinal and vertical direction relative the first attachment arrangement such that when the second attachment arrangement has moved a part of the first distance, the first flexible member comes into contact with the first engagement element, thereby increasing the spring constant of the first flexible member by shortening the effective length of the first flexible member.
The first engagement element may comprise a rod extending in a lateral direction and being arranged at the second distance from the first area of the first attachment arrangement, such that when the second attachment arrangement has moved a first distance the first flexible member comes into contact with the rod, thereby increasing the spring constant of the first flexible member by shortening the effective length of the first flexible member. The rod may have any cross-sectional shape, such as for instance circular, oval, quadratic, triangular, rectangular etc.
This provides an easy, yet effective engagement element that can be easily positioned to achieve the desired shortening of the effective length of the flexible member.
The first engagement element may comprise at least one rigid or elastic member shorter than the first flexible member arranged between the first flexible member and the first attachment arrangement. An end portion of the rigid or elastic member extends beyond the first area of the attachment arrangement in a longitudinal direction of the first flexible member to the second distance, such that when the second attachment arrangement has moved at least a part of the first distance, the first flexible member comes into contact with the rigid or elastic member, thereby increasing the spring constant of the first flexible member by shortening the effective length of the first flexible member.
This provides an alternative engagement element whose size can easily be adjusted to achieve the desired shortening of the effective length of the flexible member.
The first flexible member can be mounted or set to various starting points during installation. The range of motion of the second attachment point is approximately 10-1000 mm, specifically 125-500 mm, more specifically 150-250 mm. This corresponds to a range of vertical motion of the seat is approximately 10-1000 mm, specifically 125-500 mm, more specifically 150-250 mm. Range of motions in the order of 10-100 mm can for instance be used for shock mitigation in land vehicle seats. Range of motions of 50-250 mm can for instance be used in shock mitigation in boat seats. Range of motions of 50-1000 mm can for instance be used in vehicle suspensions. A spring unit according to the disclosure can of course also be used for ranges of motion less than 10 mm and greater than 1000 mm depending on the application.
The first flexible member can be mounted such that the second attachment point, when not experiencing a load being exerted on it, is in any position along the vertical distance. E.g., the first flexible member can be mounted such that second attachment arrangement is arranged to travel vertically the whole first distance in one direction (downwards). Alternatively, the first flexible member can be mounted such that second attachment arrangement is arranged to travel vertically along approximately half the first distance in two directions (upwards and downwards), i.e., the flexible member's rest position is approximately half-way between the maximum and minimum range of travel of the second attachment arrangement.
The end portion of the rigid or elastic member may be curved and, in the longitudinal direction, may be divided into curved end portion parts. Each curved end portion part may comprise a different radius, such that when the second attachment arrangement has moved a first part of the first distance, the first flexible member comes into contact with a first curved end portion part, thereby increasing the spring constant of the first flexible member by shortening the effective length of the flexible member. When the second attachment arrangement has moved a second part of the first distance, the first flexible member comes into contact with a second curved end portion part, thereby further increasing the spring constant of the first flexible member by further shortening the effective length of the flexible member.
This provides a further means for increasing the spring constant in several steps by introducing several points on the engagement element with which the first flexible member can interact.
The first engagement element may comprise a resilient surface such that when the second attachment arrangement has moved a first part of the first distance, the first flexible member comes into contact with the engagement element, thereby increasing the spring constant of the first flexible member by shortening the effective length of the first flexible member. When the second attachment arrangement has moved a second part of the first distance, the resilient surface of the first engagement element is compressed and deformed and a contact area between the first flexible member and the first engagement element increases, further increasing the spring constant of the first flexible member by further shortening the effective length of the first flexible member.
The first engagement element may comprise a resilient element such that when the second attachment arrangement has moved a first part of the first distance, the first flexible member comes into contact with the resilient element, thereby increasing the spring constant of the first flexible member by shortening the effective length of the flexible member. When the second attachment arrangement has moved a second part of the first distance, the resilient element is compressed and deformed and a contact area between the first flexible member and the resilient element increases, further increasing the spring constant of the first flexible member by further shortening the effective length of the flexible member.
A first engagement element comprising a resilient surface or a first engagement element being a resilient element has the advantage that when the second attachment arrangement has moved a second part of the first distance, the resilient surface or resilient element is compressed and deformed becoming more compact and a contact area between the resilient surface or element and the first flexible member increases. This further increases the spring constant of the first flexible member by further shortening the effective length of the flexible member. Additionally, the resilient element provides a smooth transition between the various effective lengths of the first flexible member and can also be designed to add to the increase of the shock mitigating effect of the entire spring unit by that the resilient element requires more force to compress the resilient element further the more it is compressed. This will lead to that the spring constant of the first flexible member will increase non-linearly and/or progressively the more the resilient element is compressed.
The position of the first engagement element can be adjusted in the longitudinal and/or vertical direction to adjust the increase of the spring constant of the first flexible member.
This allows for an adjustment of the increase of the spring constant of the first flexible member.
The spring arrangement may further comprise a second flexible member being attached to and extending between the first attachment arrangement and the second attachment arrangement. Attachment points of the second flexible member to the first and second attachment arrangements are arranged at a third distance essentially vertically above or below attachment points of the first flexible member to the first and second attachment arrangements.
In this way, more stability can be added to the spring unit and the first and second flexible members can cooperate in creating a desired total spring constant of the spring unit. All of the above-described engagement elements can be used for the first and the second flexible member. The first and second flexible member can each have a different type of engagement element that can be individually fine-tuned if necessary.
The first flexible member and the second flexible member may be plates or beams and may be made of any flexible material such as metal, composite, fibre-reinforced composite or a polymer or a combination of such materials. One example of a combination of materials can for instance be a composite reinforced with metal strips running longitudinally along the flexible member. In the description, spring constant is meant to be interchangeable with the stiffness of a cantilever plate or beam as one end of the plate or beam is fixed while the other end of the plate or beam can move freely.
This shape of flexible members is easy to manufacture and adapt and leads to the best effect.
The disclosure also relates to a seat arrangement, where the seat arrangement comprises a spring unit according to the above description.
Such a seat arrangement will provide good shock mitigation.
The disclosure also relates to a suspension arrangement, where the suspension arrangement comprises a spring unit according to the above description.
Such a suspension will provide a good shock mitigation.
The disclosure also relates to a surface vehicle comprising a seat arrangement and/or a suspension arrangement according to the above. Within the context of this application, a surface vehicle is a vehicle that can operate either on a land surface or a surface of a body of water, or both.
A surface vehicle can benefit from either being equipped with a seat arrangement or a suspension arrangement according to the disclosure or both.
The disclosure also relates to a method for changing a spring constant of a spring arrangement in a spring unit. The spring unit comprises a first attachment arrangement and a second attachment arrangement. A first flexible member is attached to and extends between the first attachment arrangement and the second attachment arrangement. The method comprises:
The method may further comprises:
The method may further comprise:
The vertical position of the first engagement element relative to the first flexible member determines the first distance the first flexible is allowed to move before it comes into contact with the first engagement element. The longitudinal position of the first engagement element essentially determines the magnitude of the increase of the spring constant of the first flexible member after it has come into contact with the first engagement element and thereby the force required to make the first flexible member move further.
The method may further comprise:
The method may further comprise:
A second flexible member extending in a length direction and a width direction may be attached to and extend between the first attachment arrangement and the second attachment arrangement, where the method may further comprise:
Within the context of this application, a surface vehicle is a vehicle that can operate either on a land surface or a surface of a body of water, or both. Non-limiting examples of surface vehicles are sailboats such as a sailing yacht, motorboats such as a go-fast boat or a wheeled or tracked land vehicle such as sandrails, dune buggies or tanks. Hovercrafts is one non-limiting example of a surface vehicle that can operate on both a land surface and a surface of a body of water.
For a definition of a go-fast boat, see for instance https://en.wikipedia.org/wiki/Go-fast_boat or https://www.discoverboating.com/resources/go-fast-boats. These types of boats include rigid-hulled inflatable boat (RHIB) often used by law enforcement and military. The seat arrangement can also be used to good effect in surface vehicles that operate on land, especially where the there is a need to traverse uneven terrain and/or roads.
In the description, a coordinate system x, y, z (lowercase) where the x-axis is a longitudinal axis extending along the length of the spring unit 1, the y-axis is a transverse axis extending from side to side of the spring unit 1 and the z-axis is the vertical axis extending along the height of the spring unit 1. This coordinate system is used e.g., to describe the spatial relationship between various parts of the spring unit 1 and the direction of forces. The coordinate system is centred on the midpoint of the part of the attachment arrangement where the horizontal and vertical base plates are attached. A longitudinal direction is thus a direction along the x-axis (x-direction), a lateral direction is thus a direction along the y-axis (y-direction) and a vertical direction is thus a direction along the z-axis (z-direction).
With support structure is meant for instance a rigid structure such as a frame or bracket that can be an integral part of a vehicle or that can be rigidly attached to the vehicle. The attachment arrangement is in the most rudimentary example made of a bracket 8 comprising a horizontal base plate 8a extending in the x-y plane attached at one end to a vertical base plate 8b extending in the y-z plane. Two vertical mounting plates extending in the x-z plane attached to the horizontal and vertical base plates at each lateral end (not shown) make up the attachment arrangements. The first flexible member 5 is arranged in a space created between the above-mentioned plates.
The first flexible member 5 is a rectangular or quadratic plate or beam with a thickness in a vertical or z-direction smaller than a thickness in a lateral or y-direction and a length in the longitudinal or x-direction longer than the thickness in a lateral or y-direction. The first flexible member 5 may be made of any flexible material such as metal, composite, fibre-reinforced composite or a polymer or a combination of such materials. In the description, spring constant is meant to be interchangeable with the stiffness of a cantilever plate or beam as one end of the plate or beam making up the flexible member 5 is fixed while the other end of the plate or beam can move freely.
The various plates of the attachment arrangement can be made of a material such as metal, composite, fibre-reinforced composite or a polymer or a combination of such materials. The horizontal and/or vertical base plates are arranged to attach to the support structure 6.
In the context of the disclosure, vertically means along the z-axis of the x, y, z-coordinate system of
As mentioned above, by having a spring unit 1 with a spring arrangement 4 comprising a first engagement element 7, the first flexible member 5 can be made to have a varying spring constant, before and after the second attachment arrangement 3 has moved a part of the first distance L_1. In this way, the shock mitigating effect of the spring unit 1 can be made to increase if the second attachment arrangement 3 moves beyond a certain distance.
In
The first engagement element 7 is arranged at a second distance L_2 from the first attachment arrangement 2 in a longitudinal or x-direction and vertical or z-direction relative the first attachment arrangement 2 such that when the second attachment arrangement 3 has moved a part of the first distance L_1, the first flexible member 5 comes into contact with or engages with the first engagement element 7, thereby increasing the spring constant of the first flexible member 5 by shortening an effective length L_eff of the first flexible member 5.
The second distance L_2 can for instance be measured from an end point of the first area 2a of the first attachment arrangement 2 or, as shown in the figure, from the centre of the spring unit's 1 coordinate system (x=0, y=0, z=0), which point is marked in the figure for illustration purposes.
With effective length, L_eff, is meant the length of the first flexible member 5 that is allowed to flex when a load is exerted on the second attachment arrangement 2. When a small load is exerted, the entire length of the first flexible member 5 that is not attached to the first attachment arrangement 2 is allowed to flex. In this case, L_eff=L. However, as soon as the first flexible member 5 comes into contact with the first engagement element 7, a part of the first flexible member 5 between the first area 5a of the first flexible member 5 and the first engagement element 7 is effectively made stationary and thus, the length of the first flexible member 5 that is allowed to flex under continued exertion by a load is now the length as measured from the first engagement element 7 instead, i.e., L_eff<L. The part of the first flexible member 5 between the first area 2a of the first attachment arrangement 2 and the first engagement element 7 will rebound or flex upwardly slightly in response to the engagement with the first engagement element 7, but this is negligible compared to the effect of the shortening of the first flexible member 5.
The first flexible member 5 is shown in
As can be seen in
In the following figures, close ups of the first attachment arrangement 2 and the part of the first flexible member 5 closest to it will be shown to illustrate various ways to achieve the above-described effect.
Depending on the desired increase of the spring constant, a rigid member or an elastic member can be selected. The rigid or elastic members can be made of a material such as metal, composite, fibre-reinforced composite or a polymer or a combination of such materials. The rigid or elastic members can be made of the same material as the first flexible member 5, but it is not necessary.
Several rigid or elastic members being made of the same or different materials can be stacked on top of each other, further adding to the increase of the spring constant.
Several rigid or elastic members can also be placed side by side in the lateral or y-direction being made of the same or different materials to be able to increase the spring constant in various ways depending on if the load exerted on the attachment arrangement is at an oblique angle or not. In this variation, the rigid or elastic members can be made up of one or more strips or plates, covering the entire width of the first flexible member 5.
According to the above description, the engagement with the resilient element increases the spring constant of the first flexible member 5 by shortening the effective length L_eff of the flexible member, at least to a small degree. However, the resilient element further has the advantage that when the second attachment arrangement 3 has moved a second part L_1_2 of the first distance L_1, the resilient element compresses as illustrated by the dashed line inside the resilient element, and a contact area between the resilient element and the first flexible member 5 increases, further increasing the spring constant of the first flexible member 5 by further shortening the effective length of the flexible member. Once the second attachment arrangement has moved a third part L_1_3 of the first distance L_1, the resilient element cannot compress any further and now functions as an essentially rigid first engagement element 7. In this way, the resilient element provides a smooth transition between various effective lengths of the first flexible member 5 and can also be designed to add to the increase of the shock mitigating effect of the entire spring unit 1 by that the resilient element requires more force to compress the resilient element further the more it is compressed. This will lead to that the spring constant will increase non-linearly and/or progressively the more the resilient element is compressed.
By adapting material properties of the resilient element such as the shore number and the cross-sectional shape, the resilient element will further affect the characteristics of the spring unit 1. The resilient element may have any cross-sectional shape, such as for instance circular, oval, quadratic, triangular, rectangular etc. Alternatively, the first engagement element 7 may comprise a resilient surface that can be compressed and deformed when the first flexible member 5 has moved the second part L_1_2 of the first distance L_1, leading to that a contact area between the first engagement element 7 and the first flexible member 5 increases, further increasing the spring constant of the first flexible member 5 by further shortening the effective length of the flexible member 5.
The resilient surface or element can be made of the same materials as listed above, but can also be made of other resilient materials such as for example polyurethane, rubber or silicone or blends thereof. The resilient surface is at least 0.25 millimetres thick, more specifically 0.5 mm thick. A thicker surface reduces any noise from when the first flexible member 5 makes contact with the first engagement element 7. Alternatively put, the first engagement element 7 may comprise resilient material on the surface of the first engagement element 7, as a resilient surface according to the above, all the way through resilient material making up the entirety of the first engagement element 7.
The second flexible member 9 is attached to the first attachment arrangement 2 and to the second attachment arrangement 3 by one of the attachments mentioned above in relation to the first attachment arrangement. The second flexible member 9 is a rectangular or quadratic plate or beam with a thickness in a vertical or z-direction smaller than a thickness in a lateral or y-direction and a length in the longitudinal or x-direction direction longer than the thickness in a lateral or y-direction. The second flexible member 9 may be made of any flexible material such as metal, composite, fibre-reinforced composite or a polymer or a combination of such materials. In the description, spring constant is meant to be interchangeable with the stiffness of a cantilever plate or beam as one end of the plate or beam making up the flexible members is fixed while the other end of the plate or beam can move freely.
The first and second flexible members 5, 9 are shown in
The second flexible member 9 are attached to the first attachment arrangement 2 and the second attachment arrangement 3 by adhesive, fasteners or by a clamped attachment similar to the first flexible member 5. Different attachment methods can be chosen for the respective first and second flexible members 5, 9.
In
In addition to the engagement elements 7, 10, when using fasteners or a clamped attachment, the effective length L_eff of the first and second flexible members 5, 9 can be shortened by loosening the fasteners or the clamped attachment and shortening the distance between the second attachment arrangement 3 and the first attachment arrangement 2 before reattaching the flexible members. This can also be done when using one flexible member.
Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.
As will be realized, the spring unit as described above is capable of modification in various obvious respects, all without departing from the scope of the appended claims. For instance, when the spring unit is arranged in a suspension arrangement of a surface vehicle, the spring units orientation may need to be changed in order to achieve the desired suspension effect of the suspension arrangement. For example, the spring unit may be arranged such that the second attachment arrangement's movement is essentially the opposite, of what is illustrated in the figures, i.e. essentially upwards along the z-axis. Accordingly, the drawings and the description thereto are to be regarded as illustrative in nature, and not restrictive.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2250033-4 | Jan 2022 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/050841 | 1/16/2023 | WO |
