WO2018050743A1

WO2018050743A1 - Roller device

Info

Publication number: WO2018050743A1
Application number: PCT/EP2017/073132
Authority: WO
Inventors: Lisbeth HESSELLUND
Original assignee: Design4Liva Enk
Priority date: 2016-09-14
Filing date: 2017-09-14
Publication date: 2018-03-22

Abstract

The invention relates to a roller device for mounting on furniture legs or the likes. The roller device comprises a socket provided with a cavity and with engagement means for a body such as a leg of a furniture leg, a walker or the like and at least one wheel or roller. The roller device is particularly directed to aid persons having difficulties in moving chairs back and forth when sitting down and getting back up, but the roller device may also be used in other connections and for other types of furniture or devices. The roller device comprises engagement means (4) comprises a plurality of elastic parts extending from the inner surface of the socket (1) into the cavity (3) and the elastic parts (4) are distributed around the perimeter of the cavity (3).

Description

Roller device

The invention relates to a roller device for mounting on furniture legs or the likes. The roller device comprises a socket provided with a cavity and with engagement means for a body such as a leg of a furniture leg, a walker or the like and at least one wheel or roller. The roller device is particularly directed to aid persons having difficulties in moving chairs back and forth when sitting down and getting back up, but the roller device may also be used in other connections and for other types of furniture or devices.

Background for the invention

Many different roller devices or wheels for furniture and similar equipment are known from the prior art.

US 5.727.284 discloses an adapter which may be removably attached to an object such as a leg of a furniture, the adapter comprises engagement means in form of screws or similar. The adapter is further provided with a wheel being swingably retractable so that the furniture can be made stationary without having to remove the adapter.

US 5.742.977 discloses a wheel adapter for restaurant and industrial equipment and shelving. The wheel adapter may be slipped onto the legs of such equipment to allow the equipment to be rolled into a different location and the adapter comprises a wheel attached to a socket having an inner socket cavity. A secondary adapter is coupled to the socket and the secondary adapter has an opening allowing a leg to be inserted into the socket cavity and secured to the wheel adapter. The secondary adapter can be obtained in a plurality of different sizes, such that the opening for each secondary adapter is one of a number of different sizes and shapes corresponding to the size and shape of the leg to be inserted. The secondary adapter may be replaced by another adapter so that the overall assembly may be used with different legs.

US 9.090.126 discloses a roller assembly for a walker including a housing having a top end, a bottom end and a peripheral wall extending therebetween. The top end has a first opening extending downward in the housing and the bottom end has an opening extending upwardly in the housing. A roller comprising a ball is coupled to the housing and the roller will allow the leg of the walker to roll along a support surface. The first opening may receive the leg of a walker and a grip (30) is used to engage the leg of the walker inside the first opening. The grip comprises a plurality of spring-biased pads (32) distributed around an entire perimeter within the first opening, the grip frictionally engages the leg of the walker but is apparently not able to retain the leg during use. Therefore, a lock (38) provided with a handle (44) is also coupled to the housing in order to releasably engage the leg of the walker. The lock (38) allows the housing to be removed from the leg of the walker when the lock is positioned in the open position and the lock (38) will retain the housing on the leg of the walker when the lock is in the locked position.

The invention

Purpose of the invention is to provide a roller device which may be attached to a body such as a leg of a furniture or the like without tools and without the need to handle screws or screw like parts which may not be easy to handle for elderly persons or persons having reduced dexterity caused by illness or handicap. Also, the roller device according to the invention is easy and intuitive to apply and the roller device leaves no scratch marks on the body when the roller device is removed from the body. Although a roller device according to the invention may be durable and re-used again and again, it is not expensive and the main parts of the device may be moulded in plastic materials.

This purpose is obtained by a roller device according to the invention where the engagements means constituted by elastic parts provide a frictional engagement with the body inserted into the cavity.

A further purpose of the invention is to provide a roller device which is able to retain a body no matter what cross-sectional shape or profile the body has and the roller device should be able to adapt to bodies of different sizes.

According to some embodiments of a roller device according to the invention, a purpose is to limit the increase in height, when a roller device is mounted on a body such as a leg of a furniture or the like.

According to some embodiments, a purpose is also to provide a roller device being able to function when placed on soft carpets or otherwise irregular support.

According to some embodiments, a purpose is also to provide a roller device which may be prevented or restricted from rolling when weight is applied to the socket, i.e. when a downward force is exercised on a roller device during operation.

One aspect of the present invention relates to a roller device comprising a socket (1 ) provided with a cavity (3) and at least one roller (2), the cavity (3) has an open end configured to receive a body and comprises engagement means (4) configured to retain the body releasably in the cavity (3), where the engagement means (4) comprises a plurality of elastic parts extending from the inner surface of the socket (1) into the cavity (3), the elastic parts (4) being distributed at the perimeter of the cavity (3).

According to any embodiment of the invention, the engagement means (4) may comprise at least three elastic parts (4), or at least five elastic parts (4), or at least seven elastic parts (4), or three or five or seven elastic parts (4) distributed around the perimeter of the cavity (3). According to any embodiment of the invention, each elastic part (4) may be shaped as a plate i.e. it is at least 5 times has wide as it is thick, and each elastic part (4) may extend into the cavity (3) either horizontally or vertically and may be defined by a height, a width, a thickness and an angle a relative to the tangent to the surface of the cavity (3). The elastic part (4) may be considered plate-shaped although the thickness of the elastic part is not constant.

According to any embodiment of the invention, the elastic parts (4) may extend over at least 50% of the height of the cavity (3), e.g. over at least 60% or at least 80% of the height of the cavity (3). According to any embodiment of the invention, the cavity (3) may have a height of at least 3 cm, or at least 4 cm or at least 5 cm.

According to any embodiment of the invention, a roller device may be configured with a braking mechanism (5, 6) preventing or restricting rotation of the roller (2) when the braking mechanism is activated. According to any embodiment of the invention, the roller device may be configured with a braking mechanism comprising a spring mechanism which spring mechanism is biased when a weight is applied to the socket (1 ) during operation.

According to any embodiment of the invention, a roller device may be configured with a braking mechanism which may comprise a spring (5) and a tap (6) fixed to the roller (2), where the spring (5) is placed between the socket (1 ) and the roller (2) forcing the socket (1) and the roller (2) away from each other when the spring (5) is in an unloaded or unbiased state.

According to any embodiment of the invention, a roller device may comprise one or two rollers (2) connected or fixed to the socket (1 ) by a rotation axis (7). According to any embodiment of the invention, a roller device may comprise one roller (2) connected to the socket (1 ) by a rotation axis (7) which rotation axis (7) is deviating with the angle β from horizontal, where 5° < β < 80° and e.g. 15° < β < 75° or 25° < β < 60°.

According to any embodiment of the invention, a roller device may comprise one roller (2) shaped as part of a sphere which roller (2) does not limit the open end of the cavity and which roller (2) has a contact surface for contacting the surface (10) during operation below a central line C of the cavity (3).

According to any embodiment of the invention, the cavity (3) may be configured by a peripheral wall (8) having a height h_c and a cross-sectional area A_c, where the cross- sectional area Ac, is shaped as a circle, a square or other polygon or rectangle or a rounded form such as an oval or the like, and by a bottom part defining a bottom level of the cavity (3).

According to any embodiment of the invention, the rotation axis (7) may be fixed to the socket (1 ) at a level above the bottom level of the cavity (3) i.e. at a level corresponding to the peripheral wall (8) of the cavity (3).

According to any embodiment of the invention, the cavity may comprise between 3 and 15 plate-shaped elastic parts (4) also called elastic fins.

According to any embodiment of the invention, the plate-shaped elastic parts (4) or elastic fins may be equally distributed, i.e. fixed to the perimeter of the cavity with same distance between neighbouring fins around the entire perimeter of the cavity (3)

According to any embodiment of the invention, both the number of fins (4) and the distance between neighbouring fins (4) may be constant throughout the length of the cavity (3) where the fins (4) are positioned. According to any embodiment of the invention, the elastic fins (4) may be plate-shaped and flat i.e. the elastic fins are straight without bends or roundings.

According to any embodiment of the invention, the fins (4) may not be positioned radially, e.g. the fins may be positioned at an angle a relative to the tangent to the inner surface in the central point of fastening of the fin to the inner surface, which angle a is larger than 45° and smaller than 90°, normally 55°< a< 86°.

According to a second aspect of the present invention, the invention relates to a furniture or walker comprising at least two legs, e.g. three or four legs, where at least two of the legs, e.g. three or four legs, each are provided with a roller device according to one of the claims 1 -14. Particularly, it may be advantageous to use a roller device according to the first aspect on two or more legs of a chair.

Dictionary

Roller - a roller is a unit having a shape allowing the roller to move by rolling in at least two directions along a straight line, the roller may have any shape allowing it to roll e.g. it may be shaped as a ball or as a sphere, as part of a ball or sphere, a as wheel or a cylinder or the like.

Perimeter - the boundary of a closed plane figure (Merriam-Webster)

Elastic material - A solid material capable of recovering size and shape after deformation (Merriam- Webster)

Height of a fin - the dimension of a fin extending along a vertical central axis in the cavity which also defines the direction in which a body is inserted into the cavity. Width of a fin - the dimension of a fin extending inwards into the cavity from the inner surface of the socket in a direction perpendicular to the direction in which a body is inserted into the cavity. Down - defines in the context of the present document the direction towards the point of contact of the roller which point of contact during operation of the device will be in contact with the surface on which the roller device is rolled.

Up - defines in the context of the present document the direction opposite or facing away from the point of contact of the roller which point of contact during operation of the device will be in contact with the surface on which the roller device is rolled.

Plate-shaped part - defines that the part in question is considerably larger in two dimensions than in the third dimension, i.e. for a part having length I, width w and thickness t then t « I and t << w, normally I > 5^*t and w > 5*t.

In operation - is the state where the roller device is mounted with a body inserted into the cavity and placed on a surface such as a floor and the one or more rollers being in contact with the surface.

List of figures

The figures illustrate various embodiments of the invention, and identical reference numbers for different embodiments refer to parts having same function although the parts may have a different appearance.

Figures 1A-1 C disclose an embodiment of a roller device according to the invention, fig. 1A shows a cut-through view of the embodiment, fig. 1 B shows an upper side view and fig. 1 C show a view from above the embodiment; figure 1 D shows an enlargement of the upper end of the cavity as shown in fig. 1 C.

Figures 2A-2D disclose respectively a second, a third, a fourth and a fifth embodiment of a roller device according to the invention. Figures 3A-3C disclose different embodiments of the engagement means according to the invention.

Figures A-4B disclose an embodiment comprising a socket with an inlay-unit which may be made of a different material.

Detailed description of the invention

Figure 1A-1 C disclose a first embodiment of a roller device according to the invention. Fig. 1A shows a cut-through view of the first embodiment, fig. 1 B shows an upper side view of the first embodiment and fig. 1 C show a view seen from the upper side of the first embodiment and the line A-A in fig. 1 C indicates where the cut-through view of fig. 1A is made.

The roller device comprises a socket 1 provided with a cavity 3 and a roller 2, a body such as a furniture leg or the like may be inserted into the cavity 3 through an open end of the cavity 3. As the open end is upwards when the roller device is in use or in operation, the "open end" may also be referred to as the "upper end", and the part of the cavity being closest to the upper end is referred to as the "upper part". The cavity 3 is configured with a peripheral wall 8 having a height h_c and a cross-sectional area A_c shaped as a circle. The cross-sectional area A_c is constant for the upper part of the cavity 3 and in this

embodiment the "upper part" corresponds to approximately 80% of the height h_c whereas the cross-sectional area A_c decreases through the lower part of the cavity 3. The lowest point of the cavity 3, i.e. a position opposite and furthest away from the opening, is called the "bottom level". In general, the volume of the cavity 3 where the cross-sectional area A_c is decreasing. As the decrease in the cross-sectional area A_c has the shape of a part of a sphere, a body inserted into the cavity 3 and touching the peripheral walls 8 of the lower part of the cavity 3, will be centralised when the body is forced towards the bottom level, regardless of the shape of the inserted body.

The roller 2 comprises a rotation axis 7 which is connected to the socket 1 by a bearing e.g. a sliding bearing or a roller bearing configured in such a way that the roller 2 may rotate while the socket 1 does not. Further, the roller device comprises a braking mechanism 5, 6 which can make it impossible or at least difficult for the roller 2 to rotate relative to the socket 1 , while the breaking mechanism is activated. According to the embodiment of fig. 1A-1 C the braking mechanism comprises a spring 5 and a tap 6 where the tap 6 is fixed to or is part of the rotation axis 7 and is inserted into an opening of the socket 1. The spring 5 is placed between the tap/rotation axis 7 and the socket 1 and when there is no load on the socket 1 , the spring 5 biases the socket 1 and the roller 2 away from each other, when the load on the socket 1 exceeds what the spring 5 can carry, a surface of the socket 1 is pressed against an inner/upward surface of the roller 2 and prevents the roller 2 from rolling.

According to the embodiment of figs. 1A-1 C, the socket 1 has an outer surface which is partly shaped as a ball i.e. the outer surface facing the roller 2 and partly flat i.e. the outer surface facing away from the roller. However, the shape of the outer surface of the socket 1 as such is not significant or relevant for the functionality of the retaining ability of the roller device. The shape of the outer surface of the socket 1 as such may be relevant for the braking mechanism as it may be the outer surface which contacts and pushes against a surface of the roller 2 during braking. The open end of the cavity 3 faces upward i.e. away from a surface 10 which is in contact with the roller 2 during operation, whereas the cavity is closed downward i.e. in direction of the surface 10 with which the roller 2 is in contact during operation. The cavity 3 holds or comprises engagement means 4 which engagement means 4 may retain a body being inserted into the cavity 3. The engagement means 4 are in the shown embodiment constituted of six plate-shaped and inwardly extending elastic fins. When a body is inserted into the cavity 3, the fins will fold aside due to their flexibility, when the body is removed from the cavity again, the fins will return to their original positions due to their elasticity where the elasticity is the capability of the strained fins to recover their size and shape after deformation. How much the fins will fold aside depend on the size of the inserted body. In the embodiment shown in figs. 1A-1 D, each fin 4 comprises a piece of a flat, plate-shaped elastic material having an inclined surface 4a closest to the centre of the cavity and each fin 4 extend from the inner surface of the peripheral wall 8 towards the central area of the cavity, however, each fin 4 does not extend toward the exact centre C of the cavity 3. The fins 4 are mounted so the direction of each fin 4 deviates with (90-a)° from a direction directly to the centre C i.e. the radial direction. Such a deviation will cause all six fins 4 to fold aside in the same direction when a body is inserted into the cavity 3 thereby causing a more predictable retainment of the inserted body.

It is the intention that the roller device should be able to receive bodies of different sizes and shapes. In figure 1 D are lines indicating the minimum dimension and the maximum dimension of the cross-section of a body which can be retained in the cavity 3. The minimum dimension is marked by the dotted line and the maximum dimension is marked by the dotted line r_max. The minimum dimension is determined by the central open space between the inner surface of the fins 4, if e.g. a cylindrical body has a radius smaller than r_min, or e.g. a square or quadrilateral has sides smaller than n™, then the fins 4 will not get in retaining contact with the body. The maximum dimension r_max is

determined by the elasticity and the physical dimensions of the fins both close to the surface of the side parts at which fins are fixed and throughout the length/width of the fins. When a body is inserted into the cavity 3, the fins 4 will fold aside as the body is inserted and the body forces the fins outwards toward the inner surface of the peripheral wall 8 away from the centre of the cavity 3. If the cross-section of the body is so large that the body cannot be inserted while the fins 4 are folded along the side parts 8, then the body exceeds the maximum dimension r_max- However, the maximum dimension r_max may not be the same for a body having a round cross-section, a square or quadrilateral or a polygonal cross-section. For a given size and shape of fins and a given material a skilled person will be able to determine the exact minimum and maximum dimensions of differently shaped bodies to be inserted.

The embodiment of fig. 1A-1 C is provided with a single roller 2 shaped as a part of a spherical shell and the roller is mounted on the downwardly inclined rotation axis 7. The angle β between the rotation axis and the surface 10 with which the roller 2 has contact during operation is between 30-40°. The rotation axis 7 is fixed to the socket 1 above the bottom level of the cavity 3 and the roller 2 extends in the full height of the cavity 3. This shape and position of the roller 2 results in that the roller 2 has a large circumference making it possible for the roller 2 to pass over a soft and uneven surface while the height of the complete roller device is kept low. The roller 2 need not be constituted by a spherical shell, it may be constituted of a ring - flat or round - fixed to the rotation axis 7 by spokes. Fig. 2A discloses a second embodiment of a roller device according to the invention, fig. 2B discloses a third embodiment of a roller device according to the invention and fig. 2C discloses a fourth embodiment of a roller device according to the invention.

The second embodiment shown in fig. 2A is provided with a box-shaped or cylindrical cavity 3 without decreasing cross-sectional area A_c in the bottom section, the roller device comprises a single roller 2 in form of a ball or sphere placed below the bottom level of the cavity 3. The roller 2 is not provided with a rotation axis but is instead provided with an overlaying ball bearing consisting of a ring of a plurality of small balls allowing the roller 2 to move in all directions. According to this embodiment, the roller 2 and the cavity 3 are positioned in extension of each other and the complete height of the roller device must therefore at least be the sum of the height of the roller 2 and the height of the cavity 3.

Fig. 2B discloses a third embodiment provided with a cylindrical cavity 3. The roller device is provided with a single roller 2 having a rotation axis 7, the roller 2 is placed partly beside the socket 1 and partly below the socket 1. The rotation axis 7 is horizontal and fixed to the socket 1 at a level above the lowest part of the socket 1. The roller 2 of the third

embodiment allows the roller device to move in two directions and the height of the complete roller device will depend on where, i.e. at what level, the rotation axis 7 is mounted. If the rotation axis 7 is placed below the cavity 3, the rotation axis 7 may stretch through the socket 1 , if the rotation axis 7 is mounted at a level beside the cavity 3 i.e. above the bottom level of the cavity 3, the rotation axis 7 can only be mounted at one side of the socket 1. The embodiment may be provided with a second roller e.g. placed opposite the shown roller 2 i.e. at the other side of the cavity 3/socket 1 . If the embodiment is provided with a second roller placed at same level as the first roller, then the torque of the roller device during operation may be reduced and the roller device will be more likely to move along a straight line in two directions: back and forth.

Fig. 2C discloses a fourth embodiment of a roller device according to the invention which embodiment is provided with a single roller 2 placed centrally below the cavity 3. The roller 2 is shaped cylindrical like a care tyre. As the roller 2 is placed below the cavity 3, the height of the roller device is increased compared to the first and third embodiments where the roller 2 in the first embodiment extends over 100% of the height of the cavity 3 and in the third embodiment extends over approximately 50% of the socket (the extension of the cavity 3 is not shown in figure 2B). The roller 2 is attached to the socket 1 by a rotation axis 7 which is attached at both sides of the socket 1. A skilled person will be able to determine an optimal position, size and attachment for one or more rollers 2 for a given embodiment, depending on the specific use of the

embodiment. For indoor use, where the roller device may need to roll on carpets, a large roller is normally preferred as small rollers may be caught in the carpet. If the roller device is intended to support heavy equipment, a roller device with two or more rollers may be preferred as the load would then be distributed over a larger surface.

Fig. 2D discloses a fifth embodiment of a roller device according to the invention which embodiment is provided with a socket 1 and a cavity 3 and a single roller 2. The cavity 3 has an open end configured to receive a body such as a furniture leg and the cavity 3 comprises engagement means 4 in form of four inwardly extending fins 4. The fins 4 extends in a radial direction and comprises two pairs of fins placed opposite each other, i.e. the four fins are not positioned with same distance to both neighbouring fins. The roller 2 is fixed to the socket 1 by a tap 6.

Fig. 2E discloses a sixth embodiment of a roller device according to the invention which embodiment is provided with a socket 1 and a cavity 3 and a single roller 2. The cavity 3 has an open end configured to receive a body such as a furniture leg and the cavity 3 comprises engagement means 4 in form of four "towers" of fins horizontally extending fins. Each fin 4 extends for approximately 10-15% of the circumference of the cavity. A figure illustrating the device viewed from above is added to fig. 2E.

Figure 3A-3C illustrates different embodiments of the form and numbers of fins 4 in a cavity 3 seen from above. In fig. 3A the two shown embodiments are each provided with 3 fins 4 which are fixed to the inner surface of the cavity 3 and extending inwards in the cavity 3. In both embodiments, the fins 4 are plate-shaped but in one embodiment the fins are flat plates and in the other embodiment the fins are bend into an angular profile. The fins are fixed to the inner surface of the cavity with equal distance between the fins 4 i.e. the fins 4 are equally distributed around the periphery of the inner surface.

In fig. 3B the two shown embodiments are each provided with 5 fins 4 which are fixed to the inner surface of the cavity 3 and extending inwards in the cavity 3. In both

embodiments, the fins 4 are plate-shaped but in one embodiment the fins 4 are flat plates and in the other embodiment the fins are bend into an angular profile. The 5 fins are fixed to the inner surface of the cavity with equal distance between the fins 4 i.e. the fins 4 are equally distributed around the periphery of the inner surface of the cavity.

The embodiment of fig. 3C is provided with 7 plate-shaped fins 4 being equally distributed along the inner surface of the cavity 3. The fins 4 may be provided with an inclining end surface 4a facing the centre C of the cavity, and the inclined surface 4a may be lowest closest to the centre C of the cavity 3. Fig. 4A disclose an inlay-unit comprising the cavity 3 and the engagement means 4 of the cavity 3 and fig. 4B disclose a socket made of a relatively hard and durable material and comprising an opening. Before a roller device comprising units as disclosed in figs. 4A and 4B is put to use, the inlay-unit is placed inside the opening of the socket 1. The inlay-unit may be constructed of a relatively soft mouldable material providing an adequate friction between engagement means 4 and a body inserted into the cavity 3. The cavity 3 according to this embodiment is constituted by the inner surface of the inlay-unit and has a cross-sectional area A_c as defined by the peripheral walls of the cavity 3.

Cavity

In general, the cavity 3 is a volume being open i.e. without a wall at one end, closed at the opposite end and at the peripheral wall 8, and contained in a socket 1. The "open end" may be referred to as "the upper end" as this end of the cavity faces away from the floor or other support during operation, and the "closed end" may be referred to as "the lower end". Also, the part of the cavity being closest to the upper end may be referred to as the "upper part" and the part of the cavity being closest to the lower end may be referred to as the "lower part" of the cavity.

In general, the walls of the cavity 3 may be provided with openings either at the bottom or at the peripheral wall 8, but openings in the bottom section may not be so large or positioned in such a way that a body inserted into a cavity 3 can exit this way through the cavity 3. Also, the peripheral wall 8 may be provided with openings but the openings may not be so large or dominating that they prevent the peripheral wall 8 from having the strength necessary to keep the cavity 3 at a constant shape.

In general, the cavity 3 is configured with a peripheral wall 8 having a height h_c and with a cross-sectional area A_c, i.e. the cavity 3 has a volume: h_c*A_c, if A_c is constant, and a volume: ^c A_c( i) dh, if A_c varies. The upper-most cross-sectional area A_c is the area of at the open or upper end. The cross-sectional area A_c may be constant over the complete height of the peripheral wall 8 or for one or more sections of the peripheral wall 8 or the cross-sectional area A_c may vary. E.g. the cross-sectional area A_c may be constant for the upper part of the cavity 3 such as the upper 50-90% of the height h_c of the cavity, while the cross-sectional area A_c may decrease through the lower 10-50% of the height h_c of the cavity 3. The lowest point of the cavity 3, i.e. a position opposite and furthest away from the open end, is called the "bottom level".

The cavity 3 may have a round, rounded or polygonal cross-sectional area A_c. In general, it is found that the shape of the cross-sectional area A_c of the cavity is not significant as such, i.e. it is the position, shape (length, width etc.) and flexibility of the fins 4 which primarily determines the ability of the roller device to retain a body. However, the shape and size of the fins 4 is adapted to and at least partly determined by the shape of the cross-sectional area A_c.

A reduction of the cross-sectional area A_c makes it possible to direct the body inserted into the cavity 3 to a given horizontal position defined by the lowest point having a cross- sectional area A_c allowing the body to pass through. This feature may be used to centralize a body inserted into the cavity relative to the socket during operation.

Roller

In general, a roller device according to the invention may be provided with one, two or more rollers. The rollers should allow the roller device to move in at least two directions, back and forth along a straight line. The rollers 2 may have any shape allowing them to roll such as spherical, part of a sphere, cylindrical or ring-shaped. The one or more rollers may be mounted by a rotational axis or they may be mounted by a gliding bearing or a roller bearing or another bearing allowing each roller 2 to rotate relative to the socket 1. The roller 2 of the embodiment of fig. 1A-1 C is considered an advantageous embodiment, as this construction allows for a very low overall height of the roller device while the embodiment also allows application of a roller with a large circumference which is able to roll over soft carpets and the like without problems.

The roller may e.g. be made primarily of plastic, rubber, nylon or metal.

In general, the overall height of a roller device according to the invention may be reduced by fixing one or more rollers to a point above the lowest point of the socket 1 as this makes it possible to lower the socket 1 relative to the one or more rollers.

Engagement means /fins

The engagement means 4 are normally plate-shaped elastic parts which are extending from the perimeter of a cavity 3 and towards the central area of the cavity, the perimeter of the cavity may be round but it may also have other shapes and the engagement means may or may not point directly to the centre C of the cavity.

The engagement means 4 may be made of the same material as the socket 1 or it may be made of a different material. The engagement means 4 may be attached to the socket 1 or the socket 1 or at least the part of the socket encompassing the cavity and the

engagement means may be moulded as a single unit.

The engagement means 4 retain the inserted body by frictional engagement and comprises no tools or locking parts in form of screws, nuts or the like which must be mechanically tightened. The engagement means are also referred to as fins and the fins may e.g. be made from plastic, silicone or metal.

Each fin 4 need not extend toward the exact centre C of the cavity 3. The fins 4 may be mounted so the direction of each fin 4 deviates with the angle (90-a)° from a direction directly to the centre C i.e. the radial direction. Such a deviation will cause all fins 4 to fold in the same direction when a body is inserted into the cavity 3 causing a more predictable retainment of the body. Same effect may be obtained if the fins 4 at the surface of the side parts 8 are mounted in a radial direction while the material towards the centre is bended or folded in an angle or only the upper inner part of each fin 4 is bended or folded in an angle deviating from the radial direction. Same effect may be obtained if the fins 4 at the surface of the peripheral wall 8 are mounted in a radial direction while the material towards the centre is bended or folded in an angle or only the upper inner part of each fin 4 is bended or folded in an angle deviating from the radial direction.

If the fins comprise straight plate-shaped parts, the fins may be mounted at an angle a relative to the tangent to the inner surface in the point for fastening of the fin to the inner surface. The angle a may be larger than 45° and smaller than 90°. See e.g. fig. 1 D for illustration of the angle a. At the shown embodiment, the angle a is approximately 70° and each fin is straight and plate-shaped.

In general, the dimension and elasticity of the fins determines exactly how large a body may be inserted into a given cavity. Normally, the fins will reduce the available cavity by

0.4 - 1.0 cm, i.e. if the cavity is round having a diameter of 5.5 cm a leg having a diameter of 4.5 - 5.1 cm may be inserted, depending on the elasticity of the fins.

The number of fins may influence the possible positioning of a body having a polygonal cross-section. For a body having a square or rectangular cross-section, it may be easier to push the body into the cavity 3 and maintaining a desired orientation of the roller device relative to the body, if there is an un-even number of equally distributed fins 4, e.g. if there are 3, 5, 7 or 9 fins. If there are more than 10 fins, the number of fins seems to lose its significance.

Also, the maximum desirable number of fins may be defined by the size of the perimeter of the cavity and the width of the fins, as it may be desirable if the fins do not overlap with the neighbouring fin, when a body close to the largest possible dimension r_max is inserted into the cavity of the roller device.

A maximum number of fins may be estimated by the following equation: n_max = perimeter in mm / width of fins in mm. For example, if the cavity has a round cross-section with a diameter of 5 cm, the perimeter is = 50 mm * π = 157 mm, and if the width of each fins is 21 mm, then n_max = 157/21 = 7,5 and as n_max is a natural number it must be either 7 or 8. A skilled person will then determine the exact number n of fins based on the exact embodiment and its function e.g. the elasticity of the fins.

Normally, all fins will be of identical size, shape and elasticity and all fins will be mounted at the same level inside the cavity. Also, the distance between each set of neighbouring fins are normally identical. Alternatively, size or shape or elasticity of each fins may be varied in such a way that a desired horizontal position of a body inside the cavity may be obtained, or the size or shape or elasticity of each fins or e.g. every second fin may be varied in such a way that varying vertical positions of bodies may be obtained.

Claims

1. A roller device comprising a socket (1 ) provided with a cavity (3) and at least one roller

(2) , the cavity (3) has an open end configured to receive a body and comprises engagement means (4) configured to retain the body releasably in the cavity (3),

characterized in that the engagement means (4) comprises a plurality of elastic parts extending from the inner surface of the socket (1 ) into the cavity (3), the elastic parts (4) being distributed at the perimeter of the cavity (3).

2. A roller device according to claim 1 , wherein the engagement means (4) comprises at least three elastic parts (4), or at least five elastic parts (4), or at least seven elastic parts (4), or three or five or seven elastic parts (4) distributed around the perimeter of the cavity

(3) .

3. A roller device according to any preceding claim, wherein each elastic part (4) is shaped as a plate i.e. it is at least 5 times has wide as it is thick, and each elastic part (4) is extending into the cavity (3) either horizontally or vertically and is defined by a height, a width, a thickness and an angle a relative to the tangent to the surface of the cavity (3).

4. A roller device according to any preceding claim, wherein the elastic parts (4) extends over at least 50% of the height of the cavity (3), e.g. over at least 60% or at least 80% of the height of the cavity (3).

5. A roller device according to any preceding claim, wherein the cavity (3) has a height of at least 3 cm, or at least 4 cm or at least 5 cm.

6. A roller device according to any preceding claim, which roller device is configured with a braking mechanism (5, 6) preventing or restricting rotation of the roller (2) when the braking mechanism is activated.

7. A roller device according to any preceding claim, which roller device is configured with a braking mechanism comprising a spring mechanism which spring mechanism is biased when a weight is applied to the socket (1 ) during operation.

8. A roller device according to any preceding claim, wherein the braking mechanism comprises a spring (5) and a tap (6) fixed to the roller (2), where the spring (5) is placed between the socket (1 ) and the roller (2) forcing the socket (1 ) and the roller (2) away from each other when the spring (5) is in an unloaded or unbiased state.

9. A roller device according to any preceding claim, comprising one or two rollers (2) connected or fixed to the socket (1 ) by a rotation axis (7).

10. A roller device according to any preceding claim, wherein the roller device comprises one roller (2) connected to the socket (1 ) by a rotation axis (7) which rotation axis (7) is deviating with the angle β from horizontal, where 5° < β < 80° and e.g. 15° < β < 75° or 25° < β < 60°.

1 1. A roller device according to any preceding claim, wherein the roller device comprises one roller (2) shaped as part of a sphere which roller (2) does not limit the open end of the cavity and which roller (2) has a contact surface for contacting the surface (10) during operation below a central line C of the cavity (3).

12. A roller device according to any preceding claim, wherein the cavity (3) is configured by a peripheral wall (8) having a height h_c and a cross-sectional area A_c, where the cross- sectional area A_c, is shaped as a circle, a square or other polygon or rectangle or a rounded form such as an oval or the like, and by a bottom part defining a bottom level of the cavity (3).

13. A roller device according to any preceding claim, wherein the rotation axis (7) is fixed to the socket (1 ) at a level above the bottom level of the cavity (3) i.e. at a level

corresponding to the peripheral wall (8) of the cavity (3).

14. A roller device according to any preceding claim, wherein the cavity comprises between 3 and 15 plate-shaped elastic parts also called elastic fins.

15. A roller device according to any preceding claim, wherein plate-shaped elastic parts (4) are equally distributed, i.e. fixed to the perimeter of the cavity with same distance between neighbouring elastic parts around the entire perimeter of the cavity (3)

16. A roller device according to any preceding claim, wherein both the number of plate- shaped elastic parts (4) and the distance between neighbouring shaped elastic parts (4) are constant throughout the length of the cavity (3) where the fins (4) are positioned.

17. A roller device according to any preceding claim, wherein the elastic fins (4) are plate- shaped and flat i.e. the elastic fins are straight without bends or roundings.

18. A roller device according to any preceding claim, wherein the fins (4) are not positioned radially, e.g. the fins are positioned at an angle a relative to the tangent to the inner surface in the central point of fastening of the fin to the inner surface, which angle a is larger than 45° and smaller than 90°, normally 55°< a< 86°.

19. A furniture or walker comprising at least two legs, normally four legs, where at least two of the legs, normally four legs, are provided with a roller device according to one of the claims 1-14.