Universal Wheelchair for the Handicapped

The present invention refers to two models, Model A (Fig 1 to Fig 4) and Model B (Fig 1 1 to Fig 14) of wheelchairs for the handicapped that, beyond the normal funcionality of commonly used wheelchairs, provide its users with the possibility of performing common day-to-day functions with greater ease and independence, for example

• entering and exiting me wheelchair to and from a normal chair, a bed ou similar furniture,

• the transfer to and from a toilet seat to attend to physiological needs,

• the exercise of the body and legs whilΛ in a seated position

PRECEDESOFTHEPRESENTINVENTION

The common wheelchairs require that the user have good physical capacities and muscle tonus, or otherwise needs to be assisted by a another person, in order to transfer his body to and from the wheelchair The present invention pretends to provide the means to reduce the effort that is needed to transfer the user The solution is based on the use of bipartite seat base and back of the seat that are independent of one another so that they can be opened or closed together for the user to be able to enter or exit the wheelchair from the rear, or they can be opened or closed seperately of one another in order to use a toilet seat or for self-exercising the body and legs of the user The structure is in the form of a tipped "U" in order to create an empty space beneath the seat base for die penetration of the wheelchair over a bed or similar furniture With the objective of giving leg support and to facilitate the transfer process to the maximum, the footrest adjustment mechanism was developed so tiiat these would be free to accompany the natural motion of the users' legs during the transfer process

The Examination Report provided by the "Direccao de Servicos de Patentes" of the "Instituto Nacional of the Propπedede Industrial" referring to the search on 09/07/1997 relative to the national patente process N° 101917, brought to our knowledge the existence of the patente documents WO 92/08430 and US 4012074, considered of particular pertinence in me evaluation of the referred process, and in view of this we present the following explanation of the technical factors that we consider important in the similarities and differences between the patent documents found and the invention of the present patente request (our invention)

The patente WO92/0843Q

From what we can understand from the description of the above patente the invention comprises a mechanism for the manual regulation of the inclination of the columns of the footrests of the wheelchair via the use of the lever (19) that is the extention of the columns (9) of the footrests, rotating at the axle (25) Once the inclination is adjusted, it is maintained via the tightening of the shafts (29) that are connected to the columns (9) From the drawing it can be noted that the inclination of the footrests in relation to the respective columns is unalterable Our invention is similar to this patente only by the feet that it also has levers (33 in Fig 8) that can be moved forward and backwards by the user

What characterises and differentiates the mechanism of the footrests of our invention are the following factors

• the levers (34) comm.and the lmpulsionating springs (35) in order to free the movement of the footrests both forwards and backwards (beyond the columns of the wheelchair) when the user enters or exits the wheelchair from the rear,

• the inclination of the footrests in relation to the columns can be both manually and automatically altered along the motion of the footrests hence providing a more comfortable movement of the users' legs,

• the columns of the footrests are such that the height of the footrest can be adjusted so as to better support the users' legs in a more comfortable position (Model B only),

• the inclination of the columns of the footrests is fixed by the lock (41) and is not ad _j ustable, and we are open to the possibility of the patente WO92/08430, after due automation, being incorporated into our wheelchair

The patente US 4012074

From what we can understand from the description of the above patente the invention is characterised by the seat base and the back of the seat being longitudinally bipartite forming two lateral parts each comprised of the seat base (9), the back of the seat (10) and the armrests (8) that form a unit that swings manually about the axle (7) It compnses a structure in the form of a tipped "U" that creates an empty space for the penetration of a bed, a chair or similar furniture, and having a height adjustment mecanism composed by the parts (5, 11 and 12) that is independent for each side of the chair The four wheels of the wheelchair are all of a small dimension, being the rear wheels gyratory Our invention is similar to this patente by the fact that the seat base is longitudinally bipartite to open to the sides, the structure is in the form of a tipped "U" to create an empty space for the penetration of a bed, a chair or similar furniture and the rear wheels being of a small dimension .and gyratory

What characterises and differentiates our invention are the following factors

• me armrests (7), the back of the seats (1) and the seat base (11), being independent of one another, thus comprising greater flexibility and safety of use,

• the armrests are fixed to the structure (30) of the wheelchair and are hence permanently available for use,

• the back of the seats having a mechanism for adjusting the inclination (3, 4 and 10) and that it swings open and closed via the independent axle (8),

• the seat base having a mechanism (parts 13 to 25) for opening and closing mat functions automatically and with delay under the action of the impulsionating springs (12), and swings on the independent axle that is the column (17), having its function complemented and made easier by the automatic movement of the footrests during the transfer (Model A only),

• the seat base having a mechanism (parts 13, 26, 28, 31, 62 to 76) for opening and closing that functions automatically and with delay under the action of the impulsionating springs (73a and 73b), and swings on the independent axle that is the column (30) and also having its function complemented and made easier by the automatic movement of the footrests during the transfer (Model B only),

• the structure of the wheelchair is composed by two parts (30 and 42) that form a tipped "U" thus creating an empty space (56) for penetration,

• the front wheel is the normal size of those of common wheelchairs thus allowing the manual traction by the user, both indoors and outdoors, and situated sufficiently in front to guarantee the stability of the wheelchair without hampering the empty space for penetration,

• it comprises a mechanism for folding the wheelchair in order to facilitate its transportation

DETAILED DESCRIPTION

The present invention refers to a wheelchair characterised by the structure of the seat base being bipartite and independent of the back of the seat, and swinging automatically and with delay to the sides The automatic impulsion in Model A is confered by the spring located beneath the structure of the seat base, whereas that of Model B is confered by the springs situated in front of the vertical column of the structure of the wheelchair, both being commanded by levers The delay comes from the feet that the movement occurs only when the seat base is alleviated of the weight of the user The independence of this structure permits the opening of the seat base for the user to be able to sit on a toilet seat without hampering with the usage of other forms of supports, namely the back of the seat and the armrests that are permanently available for the user to use

The present invention is also characterised by the structure of the back of the seat being bipartite and independente of the seat base, and being manually swung to the sides and having adjustable inclination of the back of the seats via the plumber-block, thereby being ad _j ustable by the user whilst seated on the wheelchair The independence of this structure permits the opening and closing of the backs of the seat without hampering with the usage of other forms of supports, namely the seat base and the already referred armrests, thus permiting the forward and backward motion of the users' body as a form of physical exercise

The chassi, supported by the large front wheels used for manual traction and the small gyratory rear wheels, is formed by the two lateral supports that form a tipped "U" thereby creating an empty space between the lower support of the chassi and the bottom of the seat base, thus allowing the wheelchair to penetrate over a toilet seat, a bed or another similar furniture In Model B the height of the empty space is adjusted by the height adjustment mechanism that is situated in the vertical columns of the chassi

According to the present invention, the footrest support structure allows the motion of the columns of the footrests, both automatically to facilitate the entrance and exit process, and manually by means of levers that can be repeatedly moved forward and backwards by the user in order to indirectly transfer motion to his legs that would otherwise be motionless Model B has an added mechanism that permits the adjustment of the height of its columns so as to enable the adaptation of the footrest structure to the length of the users' legs

In addition to the advantages of their independent functioning, the stractures of the seat base and of the back of the seat, when operated in conjunction and with the wheelchair penetrated over a bed, a chair or similar furniture, allow the user to enter and exit the wheelchair from the rear with greater ease and safety, with a minimum of effort and without the help of other persons, thus resulting in a greater independence of the user, thereby positively contributing to their psycological well being and also to that of the people who assist the user Even in cases where the assistance of other people is absolutely necessary, the characteristics of the wheelchair contribute to reduce the effort that these people normally have to exert when they transfer the user to and from a wheelchair

The characteristics and advantages of the this invention are observable from the description that follows in reference to the accompanying drawings, in which

Fig 1 is a πght side view of die Model A wheelchair according to the invention,

Fig 2 is a top view of the Model A wheelchair with both the seat base and the back of the seat closed, and wrth the footrest supports in different positions (1 e one to the front and die other to the rear corresponding to die opposite extremes of their motion), and corresponds to the configuration of the wheelchair occupied and me user exercising his legs,

Fig 3 is a top view of the Model A wheelchair wrth both the seat base and the back of the seat open, and wrth the footrest supports in the same position to the rear, and corresponds to the configuration of the wheelchair unoccupied and ready to receive the user,

Fig 4 is a top view of the Model A wheelchair with die seat base open, die back of the seat closed and die footrest supports in the same position at me front, and corresponds to d e configuration of me wheelchair when it is occupied and the user is seated on me toilet seat,

Fig 5 shows various drawings (a) to (c), of die mechanism of the back of the seat including die inclination adjusting mechanism of e back of the seat Fig 5a is die exterior πght side view with d e back of die seat closed and d e inclination rack in position Fig 5b is die rear view of d e back of the seat showing the plumber-block, die profile of the support bar and the spindle of die rack Fig 5c is die expanded view of die casing mechanism of d e tube of die back of me seat and is supported on die rear column of die armrests, which m turn is connected to die horizontal column of die upper support of me chassi,

Fig 6 is die πght side view of die mechanism of die automatic swing of die seat base of Model A in die position of me seat base closed The figures 6b and 6c show die top view of die top and lower parts of dns mechanism where diey are connected to die column of d e chassi,

Fig 7 shows two drawings (a) and (b) of die top view of die componentes of me seat base of Model A from die nght side of the wheelchair, in die closed and die opened positions respectively,

Fig 8 shows two diagrams of the adjustment mechanism of die footrests, where figures 8a and 8b are exteπor πght side views, and Fig 8c is an interior left side view of die mechanism in order to show die manual lock,

Fig 9 shows e folding mechanism and lock of die wheelchair, where figures 9a and 9b are top views and Fig 9c e nght side view of die mechanism,

Fig 10 shows die exterior right side view of the mechanism for adjusting die height of die Model B wheelchair as well as its braking system

Fig 11 is a right side view of die Model B wheelchair according to die invention,

Fig 12 is a top view of the Model B wheelchair wrth botii die seat base and die back of die seat closed, and wrth die footrest supports in different positions (I e one to die front and die odier to die rear corresponding to die opposite extremes of d eir motion), -and corresponds to die configuration of the wheelchair occupied and die user exercising his legs,

Fig 13 is a top view of die Model B wheelchair wrth bodi die seat base and die back of d e seat open, and wrth die footrest supports in d e same position to die rear, and corresponds to die configuration of die wheelchair unoccupied and ready to receive die user,

Fig 14 is a top view of die Model B wheelchair with the seat base open, die back of die seat closed and die footrest supports in the same position at the front, and coπesponds to die configuration of die wheelchair when it is occupied and die user is seated on die toilet seat,

Fig 15 is die nght side view of die mechanism of the automatic swing of the seat base of Model B in die closed position of die seat base The figures 15b to 15d show separate detailed side views of die parts of die mechanism,

Fig 16 shows two drawings (a) and (b) of die top view of die componentes of die seat base of Model B from die nght side of die wheelchair, showing how it is transversally bipartite,

Fig 17 shows the exteπor πght side view of die Model B mechanism for adjuring die height of die footrests,

The drawings presented are non-limiting examples of the present invention

CONSTITUTION

The mechanism of die back of die seat (Fig 5a) includes die inclination adjustment of die back of die wheelchair, and is composed by die back of die seat (1), connected to die hoπzontal extremity of the tube (2) by die plumber-block (9a) The opposite extremity of the tube is bent vertically in order to serve as an axle (8) when it is put into die front column of die armrests (5a),

dius allowing die horizontal swing of die back of die seat In die closed position, die tube (2) is placed in die casing of die dovetail (5c) The back of die seat has a second plumber-block (9b) mat connects die back of die seat to one of die extremities of the rack (4) that adjusts die inclination of die back of die seat, havmg die otiier extremity connected via die spindle (3) diat is connected onto die support bar (10) The plumber-blocks (9a) and (9b) (Fig 5b) envolve die tubes diat serve as axles d at permit die inclination of die back of die seats The bar (10) is connected to die tube (2) and supports die spindle (3) The rear column of the armrests (5b) (Fig 5c) is connected to die top structure of the chassi (30) and has its top end connected to die casing (5c) of die dovetail of die tube (2) The armrest is connected on top of die casing (5c)

The automatic swing mechanism of die seat base of the Model A wheelchair (see figures 6 and 7) is composed of die rotating structure (13) diat has die bipartite seat base (11) connected on top of it, .and is supported on die gyratory column (17) with pawn (24) at its lower extremity and aligned by die top bracket (21) and die casing (23) The lever (14) is supported by d e screw axle (18) connected to die column (17), having a shaft (15) that rotates die sleeve (19) via the connecting bracket (25), wrth a spring (16) diat actes on die shaft (15) diat locks at die groove (20) The impulsive spring (12) connects the rotating structure (13) of die seat base to die sleeve (19) via die spindle at its bottom The movement of the spindle (22) connected to die column (17) is limited by the bracket (27) diereby controlling die one quarter swing of die seat base

The automatic swing mechanism of die seat base of die Model B wheelchair (see figures 15 and 16) is supported on die top column of die chassi (30) diat serves as axle to die mechanism and supports die plate (26) of die lever axles (see Fig 15b), the axle of die roller (69) and die support ring (67) tiiat is connected to die column Below tins πng runs a vertical guiding groove (31) neccessary for die adjustment of die height of die wheelchair The automatic swing mechanism is composed of

• a rotating seat structure (66) (see Fig 15 c) that supports the entire structure of the seat as well as die axle of die roller (70), having a honzontal groove (29) for the passage of die axle of the roller (69),

• a lever (71) (see Fig 15a) whose axle works on die plate (26) and commands die intermediate shaft (72) wrth rectilinear motion between the lever (71) and die impulsive springs (23a and 23b), separated at a fixed distance in die enveloping tube (74) diat is connected via an axle to die support (75) of the sleeve (68),

• a sleeve (68) diat nses and fells embraces d e rotating seat base structure column (66) and has two grooves (see Fig 15d), one vertical (28) where die roller (69) works and another diagonal

(76) where the roller (70) works, and also has die support (75) that receives die axle of die enveloping tube (74)

The structure of die seat itself (see figures 6a and 7) is constituted by a rotating structure (13 and 16) supported on the column (30) that serves as axle, having the rear half seat (62) connected on die top side The front half seat (63) is movable in relation to die structure (13) as a result of it being supported by two swinging lances (64) situated below die structure (13) These lances are supported on the axle (65) such that there is a small spacing between itself and the structure (13) so as to permite its mobility The rotating structure (13) has an empty space (32) (see Fig 16b) so as to allow the seat base to swing over die traction wheel of the wheelchair

The footrest mechanism (see Fig 8a and 8b for Model A and Fig 17 for Model B) is supported on two axles on die bracket (26) that is connected to die top structure (30) of die chassi This mechanism is composed of a lever (34) that commands die spring (35) that is connected to die support column (36a) at its opposite end The lever (33) fits onto die top extention of die support column (36a) which, in harmony with die equihbπum column (36b), maintains die footrest (39) at the same angle wrth reference to die floor This is made possible by die fact diat die footrests are connected to die ends of die columns (36b and 36a) via an axle and a plumber-block (40) respectively The mechanism is also composed of a manual lock (41) for positioning die columns (see Fig 8c) The columns (36) of the footrests of Model B serve as sleeves to die top ends of die lower tubes of die columns (38) of the footrests, where die adjustment is made by use of interchangeable pins (37)

The folding mechanism of die wheelchair (see figures 9a and 9b) is supported on four axles (43), having two connected at die front extremity of die bottom structure of the chassi (42) and two connected at die column of die bottom structure It has four articulated horizontal bars (44) having two central axles (45) and one control bar (46) mat supports die axle (48) of die handle (47), diat acts as botii a latch and as a lock This handle has four locks (49) (like lion teeth) diat .mobilize die bars (44) when the handle is placed on the two bedding grooves (50) of die bars (44), thus maintaining diem in a straight line and consequently die wheelchair in an open configuration

The mechanism for adjusting die height of die Model B wheelchair (see Fig 10) compnses a column (51), at seives as sleeve to die column of die upper structure of die chassi (30), having a vertical guiding groove (31) where a vertical rack (53) connected to die inteπor of die column (51) serves as guide and nses and lowers the column (30) It consists also of a rotating shaft (57) inside die column (30) having a screw (58) on its lower end where it is supported by die supporting block

(59) The top part of die shaft passes to die exterior of die column (30) at the curvatura of the column and terminates wrth a removable lever (60)

The axle of the traction wheel (54) is supported on die bracket (52) diat is connected to the column (30) of die chassi, whilst the gyratory wheel (55) is connected at the rear extremity of the bottom structure (42) of the chassi

OPERATION

Entering and exiting the wheelchair

It should be noted diat the user of this wheelchair enters and exits the wheelchair from the rear So being, and wrth die user seated on a bed or similar furniture, he brings die open wheelchair towards him placing his legs between die sides of the wheelchair and places his feet on die footrests (39) (the open wheelchair means that botii die seat base and die seat back are open (see Fig 3) and d e footrests are posrtioned towards die rear (see Fig 8b)) He tiien activates, firstly the lever (34 of Fig 8) forward in order to free the motion of die footrest mechanism, and secondly die lever (14 of Fig 6 or 71 of Fig 15) forward in order to tension die impulsive springs diereby activating die closing mecanism of die seat base (tins tension makes die seat base exert a slight force on die users' legs diat are in die position mat hampers the closure of die seat base) By grabbing firmly on die armrests of die wheelchair (7) (see Fig 5) and by elevating his body in order to transfer it above the ,zone of die seat base of die wheelchair, die users' legs unobstruct die motion of die seat base tiius permrting them to close automatically under die action of the tensioned springs, thereby forming a seat on which die user can sit This transfer of die centre of mass of the users' body makes die users' feet swing forward naturally and tins movement is accompanied by die footrest mecanism at maintains the users' legs in a comfortable position Once safely seated on die wheelchair, die user can now close die back of the seat (1) (see Fig 5) placing die dovetail (6) in position so diat die back of the seat becomes firmly closed The transfer process is terminated by activating the lock (41 of Fig 8) diat stabilizes the footrests at die coπect position The procedure for exiting the wheelchair is die inverse of die entering procedure

Atending to physiological needs

One of the prime objectives of the wheelchair of die present invention is to give the user the possibility to attend to his physiological needs in -an independent and secure manner This is acheived by virtue of the seat base of die wheelchair being able to open independently of the back of die seat and while still providing armrest support (see Fig 4 and Fig 14) The procedure envolves die opening -and closing of the seat base as descnbed in die paragraphs that follow, with die particularity

that the user need only lift his buttocks from the seat base onto the toilet seat and vice-versa after having activated die respective lever, instead of transfeπng his whole body as in die entering/exiting procedure

Mechanism for adjusting the inclination of the back of the seat

The adjustment of die inclination of die back of die seat (see figures 5a and 5b) is performed by the user himself whilst seated on die wheelchair The procedure requires that he lean his body forward in order to alleviate the back of the seat (1) of any pressure The user men grabbs the rack (4) and lifts it in order to liberate rt from the supporting spindle (3) so as to be able to move it forwards or backwards This movement of the rack vanes die inclination of die back of die seat as a result of the rotation of die tube (2) and of the rack (4) about their respective plumber-blocks (9a and 9b) Once the desired inclination is obtained die rack can be lowered onto die spindle (3) so diat the new inclination can be maintained

Mechanism for opening the back of the seat

The opening of the back of the seat (see figures 5a and 5c) is acheived by slightly moving the tube (2) inwards and upwards so as to release rt from the dovetail casing (5c) and en by swmgmg it outwards about its axle (8), tiius opening the back of the seat without affecting die armrests (7) that remain in position where tiiey may be needed by die user In tins open position of the back of die seat it is possivel for the user to exercise his tummy muscles by leaning forwards and backwards repeatedly since tiiere is notiung hampering this movement The closing of the back of die seat is achieved by swinging die tube (2) towards die wheelchair and tiien lifting them slightly as they approach the armrests so that the tube can be securely placed in die dovetail casing (5c)

Mechanism for moving the footrests

The motion of die footrests (see Fig 8 -and Fig 17) is acheived by unlocking die lock (41) diat frees the mechanism of die footrests, diereby allowing die levers (33) to be moved forwards -and bac-kwards and thus transfeπng that motion to the footrests (39) and consequently to the users' legs diat can be exercised in tins way As a result of the configuration of the support and equilibrium columns (36a and 36b respectively ) die inclination of die footrerts is maintained comfortable during die entire swmg of the footrests that goes beyond the column of die chassi The lever (34) commands the spπng (35) whose function is to assist in the motion of the footrests when these swing forward or backward automatically under die influence of die natural swing of the users' legs when he transfers his body whilst entering or exiting die wheelchair, tiius maintaining tiie users' legs supported during the transfer process

Mechanism for adjusting the height and inclination of the footrests of Model B

The ad u-stment of die inclination of die footrests (39) and of die height of die columns (38) of the footrests (see Fig 17) is done via die interchangeable pms (37) Firstly die height of die columns has to be adjusted by putting e pin on die support column (36a) at die desired height .After having set die height, die inclination of die footrests can be set by puttmg die pin on d e equihbπum column (36b) so as to obtain the most comfortable footreΛ posrtion for the user

Mechanism for the automatic and delayed opening and closing of the seat base of Model A

The operation of tins mechanism (see Fig 6 and 7) can be explained by considering die seat base closed and user seated on die wheelchair having the lever (14) in the rear position (the ideal posrtion so as not to hamper the other movements of the user) Lifting the lever (14) so as to free the vertical shaft (15) from the groove (20), and rotating rt out and forward until the shaft (15) locks into place at tiie opposite groove, puts the impulsive spπng (12) under tension to open die seat base (13) However, due to the larger pressure exerted by die weight of the user on die seat base, die spπng pressure is insufficiente to open die seat base, thus delaying die opening of die seat base until die user lifts his body weight off the seat base At that moment the seat base is free to respond to the tension of die spring that forces the seat base to automatically swing outwards of die wheelchair, (limited to a quarter turn by the spindle (22) and respectiva bracket (27)), diereby opening the seat base and tiius permrting the user to lower his body onto a surface tiiat would be in die empty space beneadi the seat base of die wheelchair eg a bed or toilet seat

To close the seat base the user would lift die lever (14) to free die vertical shaft (15) from the groove (20), .and rotate rt backwards and inwards until the shaft (15) locks into die opposite groove (20) In tins position the impulsive spπng (12) becomes tensioned to close die seat base (13) However, due to die feet tiiat die users' legs or body are in a position diat obstructs die motion of die seat base, die spring tension is once again insufficient to force the motion, thus delaying die closing of seat base until die user lifts his body thereby unobstructing the empty space under the seat base At that moment the seat base is free to respond to die tension of die spring d at forces the seat base to automatically swing inwards a quarter turn as limited by the spindle (22) and respective bracket (27), thus closing the seat base and providing a seat for die user to lower his body onto

Mechanism for the automatic and delayed opening and closing of the seat base of Model B

This mech.anιsm (see Fig 15a) functions in die following manner With the seat closed and the user seated on it, the position of the manual lever (71) is turned backwards (this is the ideal position so as not to interfere wrth the otiier movements tiiat the user may need to perform with his hands) In tius situation the sleeve (68) is in tiie top position as a result of the action of the impulsive

spring (23 a) havmg forced the seat column (66), tiiat supports the whole structure of the seat, to rotate a quarter turn inwards by die action of die roller (70) that functions on die intenor of die diagonal groove (76) of die sleeve (68) This sleeve moves up and down but does not rotate because the vertical groove (28) and the roller (69) impedes the rotation

To open the seat die manual lever (71) is pushed forward thereby transfenng the tension from the spring (23a) to spπng (23b) thus pressing the sleeve (68) downwards However, as a result of the larger pressure of the users' weight on the seat, the sleeve, albert under pressure to move downwards, does not operate die opening mechanism, diereby delaying the action until the user alleviates pressure on the seat base by lifting his buttocks At tiiat moment the pressure on the sleeve is greater and it moves downwards and, as a result of die action of die diagonal groove (76) and tiie roller (70), forces the seat column(66) to rotate automatically one quarter turn outwards of die wheelchair takmg with it the entire seat base structure, thus removing the seat base from within the wheelchair and allowing the user to sit on another surface that may be in the empty space under the seats of the wheelchair

To close the seat the manual lever (71) is pushed backward diereby transfeπng die tension from die spπng (23b) to die spring (23a) thus pressing the sleeve (68) upwards However, as a result of the presence of the users' legs in the seat base area, the sleeve, albeit under pressure to move upwards, does not operate die closing mechanism, thereby delaying the action until the user disobstructs the area by lifting his buttocks At that moment the pressure on the sleeve is greater and it moves upwards and, as a result of die action of die diagonal groove (76) and the roller (70), forces the seat column (66) to rotate automatically one quarter turn inwards taking with it the entire seat base structure, thus positioning the seat base and providing the user with a seat in the wheelchair

This mechanism still comprises a structure in which each half seat is spirt (see Fig 16) in two parts, one fixed half (62) diat is supported on die structure (13) of the seat and another gyratory half (63) supported on gyratory lances (64) supported on die axle (65) When the seat opens, the gyratory half (63), moves a bit more backwards as a result of die mobility that is confered by die spacing (see Fig 15a) that exists when the user leaves the seat, thereby uncovering the empty space (32) that is necessary for the seat structure to penetrate over the zone of the traction wheel of the wheelchair, even when the height of the wheelchair is adjusted to its lowest position When the seat closes and die user sits on die it, the spacing of the gyratory half, that helps to return the half seat back to its initial position is eliminated, causing a slight bend of the lances (64) and consequently the seating of the half seat onto the structure (13) of the seat

Mechanism for adjusting the height of the Model B wheelchair

This mechanism (see Fig 10) enables the user to adjust the height of die wheelchair whilst he is seated on die wheelchair, by placing the removable lever (60) on the top of the rotating shaft (57) and rotating it in order to raise or lower the column of the upper structure of the chassi (30) thus raismg or lowering the entire seating anangement and footrests of die wheelchair, thereby adjusting its height as required for use over different furniture, such as a normal bed or a hospital bed tiiat is slightly heigher

Mechanism for folding and locking the wheelchair

The folding mechanism (see Fig 9) permits die folding of die wheelchair in order to reduce its widtii thereby making it easier to transport With the wheelchair havmg both the back of the seat and the seat base open, lifting the handle (47) will free die locks (49) (see Fig 9c) of d e articulated bars (44) Pushing die handle backwards will tiien force the two articulated bars (44) to bend tiius bringing the sides of die wheelchair together (see Fig 9b) thereby folding the wheelchair The folding process is terminated after closing die seat base and die seat back

To unfold die wheelchair, the seat base and die seat back need to be opened and die handle (47) pushed forward, diereby separating die sides of die wheelchair (42) and consequently forcing the articulated bars (44) to straighten out to enable die handle to be bedded into the grooves (50) so as to lock the bars (44) with the locks (49)

REFERENCES

1- the back of the seat

2- back of the seat supporting tube

3- supporting spindle of the inclination regulator of the back of the seat

4- rack of the inclination regulator of the back of the seat

5- front and rear columns of the armrests (5a and 5b respectively ) 5c- dovetail casmg

6- dovetail fitting

7- padded armrests

8- axle of the support tube of the back of the seat (2)

9- plumber-block for connecting the tube (2) and rack (4) to the back of the seat (9a and 9b respectively)

10- support bar of the spindle (3) connected onto tube (2)

11- gyratory seat base

13

SUBSTI I U1Ε SHEET (RULL 26)

- impulsive spring of the gyratory seat base (11) - gyratory seat base structure (11) - manual lever for commanding the impulsive spring (12) - vertical shaft that controls the sleeve (19) - pressure spring of the vertical shaft (15) - vertical column of the seat structure (13) - screw of the axle of the lever support (14) connected to the column (17) - rotating sleeve impulsionated by die spπng (12) - groove of the lock of the vertical shaft (15) - top bracket for the support and alignment of the column (17) - spmdle that controls the quarter turn of the column (17) - casing that supports and aligns die bottom of die column (17) - pawn of the column (17) - connecting bracket of the sleeve (19) to the shaft (15) - support bracket of the axles of the levers (33 and 34) and of the columns of the footrests (36) - bracket of the spindle (22) - vertical groove of die sleeve (68) - horizontal groove of the seat base column (66) - column of the upper structure of the wheelchair chassi - guidmg groove on the column (30) for the passage of the height adjustment rack - empty space for the penetration of the traction wheel - removable manual lever for moving the footrest structure - lever that commands the spring (35) - impulsive springs of the footrest mechanism - support and equihbπum columns of the footrest (36a and 36b respectively) - interchangeable pms for adjusting tiie height of the columns (36) - lower tubes of the columns of the footrest - articulated footrest - plumber-block of the footrest - manual lock for positioning the columns (36) - bottom structure of the chassi - axles of the foldmg mechanism common to the bottom strurture of the chassi (42) - articulated bars with axles at its extremities - central axles of the articulated bars (44) - control bar of the articulated bars (44) - handle for opening and closmg die folding mechanism

14

SUBBSTITUTE SHEFT (RUl E 26)

48- axle of die handle (47)

49- locks of the handle (44)

50- grooves for the bedding of the handle (47)

51- column of die lower structure of die wheelchair chassi

52- plate for the support of the traction wheel axle and of die brakmg system

53- vertical rack for adjusting the height of the wheelchair

54- traction wheel

55- gyratory wheel

56- empty space for penetrating over a bed ou similar furniture

57- rotating shaft for adjusting die height of die wheelchair

58- screw for adjusting die height of die wheelchair

59- supporting block of the axle of the rotating shaft (57) connected to die tube (30)

60- removable lever for adjusting the height of the wheelchair

61- column of die braking system

62- fixed rear half of the gyratory seat base

63- free front half of the gyratory seat base

64- lances of the free front half of the gyratory seat base (63)

65- axle of the lances (64)

66- seat base structure column

67- support ring connected to die column (30)

68- impulsive πse-and-fell sleeve

69- roller connected to die column (30)

70- roller connected to ti e seat base structure column (66)

71- manual lever that commands the springs (73)

72- intermediate shaft of die lever (71)

73- upper and lower impulsive springs (23a and 23b respectively) of die sleeve (68)

74- enveloping tube of the springs (73)

75- stud tiiat connects the tube (74) to the sleeve (68)

76- quarter turn diagonal groove of the sleeve (68)