Patent Description:
The existing types of medical chairs, nursery chairs, or examination chairs such as gynaecological or stomatology chairs (hereinafter as chairs generally) stand, in majority cases, statically in one place and use to be also very heavy. Therefore, they are difficult to be moved, usually several people or any transport equipment such as walkie truck are needed to move such chair to another place.

Some medical or nursery chairs, tables or beds may be equipped with two or four handling wheels to be transported or moved. The prior art recognizes visible wheels of small diameter to obstruct as less as possible due to the fact that the wheels are visible. In addition, such wheels need to be equipped with a brake to avoid any undesired movement of a chair or bed when examining a patient, or to avoid passing under a patient and consequent fall of a patient causing other injuries. Visible wheels incline to be dusty because they are not used often and therefore become a source of impurities which causes another problem to caregivers.

As previously said, disadvantage of these wheels is necessity to have a brake. Should a chair or any other equipment have four wheels or casters, at least two wheels need to be braked, preferably all four wheels are equipped with a brake. In case a caregiver forgets to brake a wheel, a chair may undesirably start to self-move caused by for example uneveness of the ground the chair stands on. Also, in case a caregiver forgets to brake the wheels of the chair and somebody leans against the chair, it may self-move causing risky situations with injury potential. These braked wheels have very often small brakes, difficult to access, formed as small plastic fixtures which are easy to be broken and then the wheel is not possible to be braked or unbraked at all depending in which position the brake control mechanism had been broken.

Prior art solution is described for example in the document <CIT>) showing an adjustable gauge wheel assembly for use on rotary mower decks. The wheel and its axle are carried on an arm which is pivotally supported by a deck mounted bracket. The pivotal support is adapted to allow the arm to be shifted towards and away from the bracket. The axle includes a portion which protrudes through the arm for insertion into one of the plurality of vertically spaced openings in the bracket as the arm is shifted. The bracket therefore provides for vertical adjustment of the gauge wheel as well as a direct support against impact loadings encountered by the wheel. An over-centre latch mechanism is provided to lock the arm in its adjusted position. Disadvantage of this assembly is that each time a user wants to change the wheel position, he needs to release the wheel from the given opening and move it into another opening and fix it again in this position by latch mechanism. To make such change the user needs to have necessary tools available and with him.

A document <CIT> describes amphibious structure with retractable suspension system whereas handling wheel of this structure move from chassis toward the floor using lever mechanism where the lever draws the wheel from one position to another position. Disadvantage of this solution is very difficult manipulation, complex technical design, necessity to have sufficient space around and finally financially demanding structure.

A document <CIT> describes rear wheel of a mower or reaper whose height is adjusted using an adjusting element with many openings on the bottom part of the tube coupled with the frame of the mower. To change the wheel position a user needs to have relevant tools again which the innovative solution presented in this document removes. Despite possibility to adjust the height position of the wheel in this prior art document, the solution is in principle very unpractical. Upon each change the position needs to be manually changed in the given opening and fixed by a screw.

A document <CIT> refers to rescue stretchers having height adjustable elements or rollers fixed to rotatable arm mounted to the stretcher. Change of position of adjustable elements is done by control lever <NUM> - change of position is not caused by automatic movement due to gravitation effects when the position of the entire equipment (in this case stretcher) is changed. A caregiver needs to use the lever to set a position of the rescue stretcher. This solution is not convenient as it needs an additional lever mounted on the stretcher (as well as wheels/rollers) and an effort of the caregiver to use the lever and physically change the position of the stretcher.

A document <CIT> describes a chair with hidden wheels. The wheels move by using a pulley, a sprocket and a rod fixed to the lever located in the armrest. The solution is hidden, however not automatic when the chair changes position, in addition it is expensive and prone to failure (when a chain is torn, the entire mechanism must be dissembled, and the broken component replaced).

The aim of this technical solution presented herein is to deploy or release a wheel from under the base frame so that the chair could move from one place to another. The mechanism is designed to be easily handled without necessity of using any other tools and to be cheap and simple in construction. The subjected mechanism works based on change of position of the equipment under which the mechanism is located.

The abovementioned substantial disadvantages are solved by presented hidden handling or manipulating wheel. The hidden handling wheel is preferably used with any static standing equipment or furniture such as nursery and medical patient support apparatuses, medical and examination chairs of any type etc. It may be used also outside medical area with other types of furniture such as chairs, beds, bedside tables, tables, cases, cabinets, sofas etc. The hidden handling wheel is used for easy transport of any equipment from one place to another or for partial movement aside.

Mechanism of adjustable handling wheel comprises a base frame, a supporting member, which may be a part of the base frame in preferred embodiments, and two arms where at least one of the arms is a supporting arm which the handling wheel is attached to, and another arm is a control arm with a slotted link.

The adjustable handling wheel is attached to the base frame by supporting arm, which is fixed to the base frame by means of a pin at one end and at another end is the handling wheel fixed by a pivot or a screw. The supporting arm is coupled with second arm, which is a control arm, using a pin as well. The control arm comprises a slotted link with a groove in which is a sliding member through which the pin from the supporting arm goes through. The pin of the supporting arm is pivotably fixed in the slotted link of the sliding member of the control arm which is attached to the base frame at least at one end of the control arm. Preferably, both arms are attached to the supporting member, which can be for example any profile fixed to the top side of the base frame so that the wheel becomes part of the base in the retracted, i.e. non-handling, position.

A fundamental part of this innovative solution presented herein is a mechanism of positioning of the handling wheel. The supporting arm of the adjustable handling wheel moves by means of a pin located in the sliding member, which is a part of the slotted link of the control arm, kinematically according to which position the base frame of a chair, or any equipment, is tilted to. In the first position - retracted, i.e. non-handling position, the pin in the slotted link is in its highest position. If it is necessary to use the handling wheel and thus activate the wheel, the base of a chair, or similar equipment, needs to be raised up at one side to become tilted and the pin of the supporting arm comprising the sliding member in the slotted link could move thanks to gravitation into the prepared activating position to roughly middle part of the slotted link where the pin falls into the activation point of the slotted link. The pin with sliding member gets jammed in this activation point of the slotted link and locks or secures the wheel in the active, i.e. handling, position by virtue of own weight of the chair, or other equipment. The active, i.e. handling, position causes lifting the chair, or other equipment, above the ground and easy handling or transport of a chair from one place to another, or moving the chair aside to required place. In case the wheel needs to be deactivated again and get to the retracted, i.e. non-handling, position, the chair needs to be easily raised up again so that the pin of the supporting arm comprising the sliding member in the slotted link could move thanks to gravitation into the lowest position - so called prepared deactivating position where the pin releases. When moving the chair, or other equipment, back to plain level, the pin moves in the slotted link of the control arm, thanks to own weight of the chair, into the highest position - retracted, i.e. non-handling, position, where it remains. The adjustable handling wheel changes its position into the retracted, i.e. non-handling, position where it remains until being activated again by changing position or rather tilting of the chair.

In the preferred embodiment, two hidden adjustable handling wheels are located under a chair, or any other equipment, against each other in the middle of the base frame. Optionally, at least one adjustable handling wheel is located under a chair, or any other equipment, which enables moving the said chair or equipment to any required place. In another preferred embodiment, any number of such adjustable handling wheels can be attached to the base frame depending on the size of the subjected chair, or equipment, and then the size of the mechanism of adjustable handling wheel will pro rate correspond to the size of the given chair, or equipment. The adjustable handling wheel is preferably made from metal components but can be made from metal alloys, plastic material or combination of plastic and metal materials with sufficient rigidity and bearing capacity.

<FIG> shows side elevation of an equipment <NUM>, in this case a chair, comprising a support deck <NUM> divided into a seat part and a backrest part with positionable mechanism <NUM> of a backrest part of a chair, a lifting mechanism <NUM>, telescopic columns in the preferred embodiment, a base frame <NUM> of chair, which is covered together with motors of telescopic columns of the lifting mechanism <NUM> by a cover <NUM>. The cross-section projection of the cover <NUM> of the base frame <NUM> shows an adjustable handling wheel <NUM> fixed on the upper side of the base frame <NUM> to an elevated supporting member <NUM>, which has a form of a profile or a tube. In the preferred embodiment the supporting member <NUM> is a part of the base frame <NUM>, or optionally, the supporting member <NUM> may be attached to the base frame <NUM> by means of pins, rivets, screws, weld joints or any other convenient method. A mechanism of the adjustable handling wheel <NUM> is fixed to the elevated supporting member <NUM>. The mechanism of the adjustable handling wheel <NUM> comprises, in the preferred embodiment, two arms, whereas the first arm, a supporting arm <NUM>, is attached to the supporting member <NUM> at least at one end of the supporting arm <NUM>, and at another end the supporting arm <NUM> is attached to the adjustable handling wheel <NUM>. The first supporting arm <NUM> is attached to the supporting member <NUM> of the base frame <NUM> and the adjustable handling wheel <NUM> by means of pins <NUM>. The supporting arm <NUM> comprises, in the preferred embodiment, three types of such pins <NUM>, whereas the first pin 10a couples the supporting arm <NUM> with the supporting member <NUM>, the second pin 10b couples the supporting arm <NUM> with the adjustable handling wheel <NUM> and the third pin 10c couples the supporting arm <NUM> with a control arm <NUM>. The first supporting arm <NUM> is coupled with the second arm, the control arm <NUM>, by means of pin 10c, which goes to the second control arm <NUM> through a slotted link <NUM> and a sliding member <NUM> of the second control arm <NUM>. The second control arm <NUM> is attached to the supporting member <NUM> of the base frame <NUM> at least at one end by means of a fourth pin 10a and at another end the control arm <NUM> comprises the slotted link <NUM>, in which the sliding member <NUM> moves freely. The pin 10c of the first supporting arm <NUM> of the adjustable handling wheel <NUM> goes through the sliding member <NUM>. The <FIG> shows the adjustable handling wheel <NUM> in the retracted, i.e. non-handling, position 1A, where the base frame <NUM> of a chair <NUM> is in the static position with no need to move or transfer it.

The <FIG> shows axonometric projection of a part of a base frame <NUM> with a mechanism for fixing an adjustable handling wheel <NUM> in the prepared deactivating position 1D. The <FIG> obviously shows that the base frame <NUM> of a chair <NUM> comprises a supporting member <NUM> on the upper side, which has a form of a profile or a tube. In the preferred embodiment the supporting member <NUM> is a part of the base frame <NUM>, or optionally, the supporting member <NUM> may be attached to the base frame <NUM> by means of pins, rivets, screws, weld joints or any other convenient method. The supporting member <NUM> is attached to a supporting arm <NUM> at least at on end by means of a first pin 10a and at another end the supporting member <NUM> is fixed to a control arm <NUM> by means of a fourth pin 10a. The <FIG> shows that the supporting arm <NUM> comprises three pins, whereas at least two pins 10a and 10b are located each at the opposite end in the middle of the supporting arm <NUM> and at least one of these pins 10a and 10b is coupled with the supporting member <NUM> at one end and at another end with adjustable handling wheel <NUM> by means of second pin 10b. In addition, the <FIG> shows that the supporting arm <NUM> comprises a third pin 10c at the upper side of the supporting arm <NUM> above the second pin je 10b of the adjustable handling wheel <NUM>. The third pin 10c couples the supporting arm <NUM> of the adjustable handling wheel <NUM> with the second control arm <NUM>. This third pin 10c of the supporting arm <NUM> is floatingly coupled with a sliding member <NUM> in a slotted link <NUM> of the control arm <NUM>. The control arm <NUM> has a form of a metal profile which comprises the slotted link <NUM> and one end in which the sliding member <NUM> with the third pin 10c of the supporting arm <NUM> moves freely, whereas the sliding member <NUM> is locked in the profile by a stopper <NUM> at least at one end of the sliding member <NUM>. At another end the control arm <NUM> is coupled with the supporting member <NUM> by means of a fourth pin 10a, which is located at the opposite end of the control arm <NUM>. Both arms, i.e. the supporting arm <NUM> and the control arm <NUM>, form in this prepared deactivating position 1D converse isosceles triangle where the adjusting handling wheel <NUM> is on the vertex of this triangle.

<FIG> shows that an adjustable handling wheel <NUM> is attached to at least one arm, i.e. a supporting arm <NUM> or a control arm <NUM>, whereas, in the preferred embodiment, the adjustable handling wheel <NUM> attached to the supporting arm <NUM> by means of a third pin 10c. In the preferred embodiment, the supporting arm <NUM> comprises at least three types of a pin, whereas at least two pins 10a and 10b, i.e. a first pin 10a and a second pin 10b, are located each at the opposite end in the middle of the supporting arm <NUM>, where the first pin 10a couples the supporting arm <NUM> with a supporting member <NUM> of a base frame <NUM> at one end, however optionally can be coupled only with the base frame <NUM>. The supporting arm <NUM> comprises a third pin 10c which is fixed on the upper side of the profile above the second pin 10b of the adjustable handling wheel <NUM>. This third pin 10c couples the supporting arm <NUM> with the second control arm <NUM> in a freely moving sliding member <NUM>, which is located in a slotted link <NUM> of the control arm <NUM>. Optionally, this third pin 10c can be located also on the bottom side of the profile of the supporting arm <NUM> under the second pin 10b of the adjustable handling wheel <NUM>, optionally the third pin 10c of the adjustable handling wheel <NUM> can be in parallel the pin 10b to fix the adjustable handling wheel <NUM> to the control arm <NUM>. The sliding member <NUM> is secured in the profile of the control arm <NUM> by a stopper <NUM> on the bottom side of the profile of the control arm <NUM>. The stopper <NUM> is in preferred embodiment a rivet, however, can be a profile dummy plug, a screw or any other form of a stopping suitable and rigid enough to keep the sliding member <NUM> in the slotted link <NUM> of the control arm <NUM>. The control arm <NUM> is a positionable arm, in the preferred embodiment it is also a supporting arm. The control arm <NUM> enables to change a position of the adjustable handling wheel from the retracted, i.e. non-handling, position 1A into prepared activating position 1B, then into the active, i.e. handling, position 1C, then into the prepared deactivating position 1D and finally back into the retracted, i.e. non-handling, position 1A by means of kinematically moving sliding member <NUM> in the slotted link <NUM> of the control arm <NUM>.

<FIG> shows side elevation of a mechanism of an adjustable handling wheel <NUM>, where the adjustable handling wheel <NUM> is shown in the retracted, i.e. non-handling, position 1A, in other words in the hidden position where the wheel is not visible. In this position the adjustable handling wheel <NUM> is not able to be used for movement of a chair <NUM>, or any other equipment, from one place to another. The mechanism of the adjustable handling wheel <NUM> comprises two arms, an arm <NUM> and an arm <NUM>, wherein the supporting arm <NUM> bears the adjustable handling wheel <NUM> and is coupled with the second control arm <NUM>, which comprises a slotted link <NUM> with a sliding member <NUM>, which is coupled with a third pin 10c of the supporting arm <NUM> so that the adjustable handling wheel <NUM> can be positioned from the retracted, i.e. non-handling, position 1A into the active, i.e. handling, position 1C, which is not shown in the <FIG>. Between these retracted, i.e. non-handling, position 1A and the active, i.e. handling, position 1C there is another position called prepared activating position 1B to activate the adjustable handling wheel <NUM> into the active, i.e. handling, position 1C. Transition into the said positions 1B and 1C is shown on the following figures. The active, i.e. handling, position 1C is followed by prepared deactivating position 1D to deactivate the adjustable handling wheel <NUM>. All positions 1B, 1C and 1D are shown and described on the following figures. The particular position of the adjustable handling wheel <NUM> is defined by a third pin 10c of the supporting arm <NUM> according to location of this pin 10c in the slotted link <NUM> of the control arm <NUM>. The schematic arrow shows a direction in which the third pin 10c will move in the sliding member <NUM> to use the adjustable handling wheel <NUM>.

In consequence to the <FIG>, <FIG> shows other position of arms <NUM> and <NUM>, wherein a supporting arm <NUM> is fixed to a supporting member <NUM> at least at one its end and at another end it is attached to an adjustable handling wheel <NUM>. Above this point of attachment to the adjustable handling wheel <NUM> the supporting arm <NUM> comprises a third pin 10c for attaching to the other control arm <NUM>, which is also attached to the supporting member <NUM> at one end, not shown herein, and at another end the control arm <NUM> is attached to a sliding member <NUM> by means of the third pin 10c of the supporting member <NUM>. The sliding member <NUM> moves in a slotted link <NUM> of the control arm <NUM>. This pin 10c is fixed tight at the opposite end to the supporting arm <NUM> on which the adjustable handling wheel <NUM> is attached to. This position is so called inter-position or prepared activating position 1B, into which the adjustable handling wheel <NUM> turns to in case the position of a chair <NUM>, or any other equipment, changes by tilting aside (heeling). At the moment the chair <NUM> occurs in tilted or heeled level, the sliding member <NUM> in the slotted link <NUM> changes position and the pin 10c with the sliding member <NUM> in the slotted link <NUM> of the control arm <NUM> moves thanks to gravitation into the appropriate prepared activating position 1B. In this position the adjustable handling wheel <NUM> is not ready yet to move.

<FIG> shows the active, i.e. handling, position 1C with visible change of position of a pin 10c from the inter-position prepared activating 1B, which is not shown herein, into the active, i.e. handling, position 1C, where the pin 10c is locked by means of a sliding member <NUM> and a slotted link <NUM> roughly in the middle of the slotted link <NUM>. In such position a chair <NUM>, or any other equipment, can be easily moved. To secure and lock the active, i.e. handling, position 1C, the pin 10c is locked in a slot of the slotted link <NUM> by means of the sliding member <NUM>, which provides locking of the chair <NUM>, or any other equipment, above the ground and enables movement of the chair <NUM> into another place. When locking the pin 10c in the slot of the slotted link <NUM> by means of the sliding member, the weight of the entire chair <NUM>, or any other equipment, is transferred to the adjustable handling wheel <NUM> and the base or undercarriage of the chair <NUM> is raised above the ground frame and the chair <NUM> can be easily moved. The same as with regards to inter-position prepared activating 1B, the retracted, i.e. non-handling, position 1A changes into the active, i.e. handling, position 1C via the inter-position prepared activating 1B thanks to gravitation when the chair <NUM> is tilted wherein upon reaching the required position 1C the own weight of the chair <NUM> levels the chair <NUM> above the ground.

<FIG> shows again the mechanism of arms <NUM> and <NUM> of an adjustable handling wheel <NUM> in another position of the adjustable handling wheel <NUM> - prepared deactivating position 1D. The position is changed at the moment, when after using the adjustable handling wheel <NUM> in the active, i.e. handling, position 1C, a chair <NUM>, or any other equipment, is moved into another required place and is raised up or tilted on one side again so that the position of a pin 10c changes kinematically by means of a sliding member <NUM> along an axis of a slotted link <NUM> of a control arm <NUM> by which a pin 10c reaches its the lowest position which is prepared deactivating position 1D shown herein. This prepared deactivating position 1D serves for returning the adjustable handling wheel <NUM> into the original position, see the following <FIG>. Deployment and movement of the adjustable handling wheel <NUM> is caused by gravitation which impacts the third pin 10c in the sliding member <NUM> of the slotted link <NUM>, when the pin 10c by help of sliding member <NUM> moves into the lowest position in the slotted link <NUM> of the control arm <NUM>.

Consequently, to all said previously, <FIG> shows the mechanism of arms <NUM> and <NUM> with an adjustable handling wheel <NUM> again in the retracted, i.e. non-handling, position 1A. The <FIG> shows a change of position of a supporting arm <NUM> and a control arm <NUM>, which in preferred embodiment, may be also supporting arm, and a change of position of a third pin 10c, which is located again in the retracted, i.e. non-handling, position 1A, previously described. The third pin 10c of the supporting arm <NUM> moved from the previous prepared deactivating position 1D in the slotted link <NUM> of the control arm <NUM> into the highest position in this slotted link <NUM>, which is enabled by freely moving sliding member <NUM>. Together with the change of position of the third pin 10c also position of the supporting arm <NUM>, to which the adjustable handling wheel <NUM> is fixed, changes, therefore also position of the adjustable handling wheel <NUM> changes. The change from prepared deactivating position 1D to another one is caused by own weights by a chair <NUM>, or any other equipment, when the weight helps to move the third pin 10c with the sliding member <NUM> into the highest position in the slotted link <NUM> of the control arm <NUM> by which the adjustable handling wheel <NUM> returns back into the retracted, i.e. non-handling, position 1A.

The last <FIG> shows a part of a chair <NUM>, particularly it shows a part of a base frame <NUM> with attached mechanism of arms <NUM> and <NUM> and an adjustable handling wheel <NUM>. The control arm <NUM> comprising a slotted link <NUM> and a sliding member <NUM> is free coupled with a supporting arm <NUM> by means of a pin 10c, which moves in the slotted link <NUM> with the sliding member into the individual positions of the adjustable handling wheel <NUM>.

Fig. 1A shows an adjustable handling wheel <NUM> in the retracted, i.e. non-handling, position, where a base frame <NUM> comprising the adjustable handling wheel <NUM> of a chair <NUM> in in one level with the ground. When changing the retracted, i.e. non-handling, position 1A into the prepared activating position 1B a sliding member <NUM> with a third pin 10c will move in the slotted link <NUM> thanks to gravitation impacting the freely supported sliding member <NUM> with the third pin 10c in the slotted link <NUM>, which enables change of a position into another position, which is prepared activating position 1B.

Fig. 1B shows the adjustable handling wheel <NUM> in the prepared activating position where a base frame <NUM> comprising the adjustable handling wheel <NUM> is in the tilted position after a chair <NUM>, or any other equipment, is raised up above the ground. By raising the chair <NUM> above the ground a third pin 10c of a supporting arm <NUM> releases in a slotted link <NUM> of a control arm <NUM> and the pin 10c moves into the prepared activating position 1B thanks to freely moving sliding member <NUM> and gravitation which impacts the chair <NUM> in the tilted position above the ground.

<FIG> also shows active, i.e. handling, position 1C of an adjustable handling wheel <NUM>. In this position the adjustable handling wheel <NUM> touches the ground and a base frame <NUM> of a chair <NUM>, or any other equipment, is above the ground raised up. The adjustable handling wheel <NUM> can be used to move or transport the chair <NUM>, or any other equipment, into the desired place. Also in this case, movement of a pin 10c with a sliding member <NUM> in a slotted link <NUM> of a control arm <NUM> is caused by gravitation which impacts the adjustable handling wheel <NUM> upon movement of the pin 10c with the sliding member <NUM> into the middle part of the slotted link <NUM> and in parallel, the weight of the chair <NUM>, or any other equipment, impacts the pin 10c and the adjustable handling wheel <NUM> in this active, i.e. handling, position 1C.

Claim 1:
An adjustable handling wheel mechanism for handling and movement of furniture, comprising a supporting member (<NUM>) attachable to a base frame (<NUM>) of the furniture, and at least two arms (<NUM>,<NUM>) characterized in that at least one arm is a supporting arm (<NUM>) of the adjustable handling wheel (<NUM>) and at least one arm is control arm (<NUM>) comprising a slotted link (<NUM>), in which a sliding member (<NUM>) moves freely, at least at one end, whereas both arms (<NUM>,<NUM>) are interconnected wherein the supporting arm (<NUM>) is attached to the supporting member (<NUM>) using a first pin (10a) at one end and at its other end is attached to the adjustable handling wheel (<NUM>) using a second pin (10b), wherein above this joint the supporting arm (<NUM>) is coupled with the control arm (<NUM>) which is attached to the supporting member (<NUM>) using a fourth pin (<NUM>) at the opposite end of the control arm (<NUM>), wherein the supporting arm (<NUM>) bears the adjusting handling wheel (<NUM>) which moves from at least one position to another position using the third pin (10c) in the sliding member (<NUM>) of the slotted link (<NUM>) of the control arm (<NUM> ), wherein the particular position of the adjustable handling wheel (<NUM>) is defined by the third pin (10c) of the supporting arm (<NUM>) according to location of this third pin (10c) in the slotted link (<NUM>) of the control arm (<NUM>).