joystick

Abstract

Joystick comprising an activation rod (22) that can be moved with respect to a respective support body (2, 3, 4) and provided with a first magnetic element (50) interacting with a Hall sensor (40) configured to produce electrical signals that can be used to control an electrically controllable device (AP) in function of the position assumed by the first magnet (50) with respect to the Hall sensor (40). The movement of the activation rod is determined by overcoming a resistive force provided by a contrast element configured to maintain the activation rod in a neutral position. Said contrast element is a second magnetic element (6) arranged in said body (2, 3, 4) in a position opposite to the first magnetic element (50) with respect to the Hall sensor (40). The second magnetic element (6) is arranged on a support (44) which allows its distance with respect to the first magnetic element (50) to be varied.

Description

[0001] TITLE

[0002] Joystick, sfe sfe sfe

[0003] DESCRIPTION

[0004] The present invention relates a joystick type control device.

[0005] It is known that a joystick is a device that can be used to convert the movements performed by a lever operated by a user into electrical signals that allow the control of a program, an electrical device or a mechanical device.

[0006] In particular, the joystick that is the subject of the present invention can be used to equip wheelchairs for the disabled and similar devices whose movements are determined by the operation of a lever or similar control element provided by a joystick.

[0007] Generally, a magnet is mounted on the lever of a joystick that interacts with a Hall sensor interfaced with a control circuit that transduces the movements of the lever, detected by the Hall sensor, into electrical signals used by a system that controls the unit controlled by the joystick. In wheelchairs for the disabled equipped with an electric drive unit, the unit controlled by the joystick is the so-called “power module”.

[0008] In a known configuration, a helical spring is mounted on the lever, whose mechanical characteristics determine the value of the force required for the user to operate the lever. In other words, the user overcomes the resistance of the spring when he moves a magnet with respect to the Hall sensor. However, springs are imprecise devices, due to the manufacturing methods and because over time they can lose their original mechanical properties, thus determining a first drawback.

[0009] Another drawback of the known technique derives from the fact that the joystick actuation force can be modified only by replacing the spring.

[0010] The main purpose of the present invention is to provide a joystick control device in which it is possible to adjust the actuation force without replacing internal components, having the characteristics indicated in claim 1. Other innovative characteristics are the subject of the dependent claims.

[0011] Among the advantages offered by the present invention, it is possible to list the following: it is possible to ensure greater precision in the actuation of the joystick even after prolonged use over time, unlike joysticks in which the actuation force is determined by a spring; it is also possible to make the joystick in a configuration that allows to substantially adjust the value of the actuation force of the joystick without having to replace any internal component; it is therefore possible to customize the joystick according to the current needs and motor skills of the user; it is possible to implement an automatic re-calibration function of the Hall sensor in the microprocessor unit that processes the signals coming from the sensor itself; the joystick object of the invention can be used to equip wheelchairs already available on the market.

[0012] These and further advantages and characteristics of the present invention will be better understood by any person skilled in the art thanks to the following description and the attached drawings, provided by way of example but not to be considered in a limiting sense, in which:

[0013] - Fig. l is a front view of a possible embodiment of the present invention;

[0014] - Fig. 2 is a sectional view along the line A-A of Fig. 1;

[0015] - Fig. 3 is a front view of a possible embodiment of a first body forming part of the embodiment of the invention illustrated in Fig. 1;

[0016] - Fig. 4 is a sectional view along the line B-B of Fig. 3;

[0017] - Fig. 5 is a front view of a possible embodiment of a second body forming part of the embodiment of the invention illustrated in Fig. 1;

[0018] - Fig. 6 is a top plan view of a possible embodiment of a third body forming part of the embodiment of the invention illustrated in Fig. 1;

[0019] - Fig. 7 is a sectional view along the line C-C of Fig. 6;

[0020] - Fig. 8 is a front view of a possible embodiment of a support body forming part of the embodiment of the invention illustrated in Fig. 1;

[0021] - Fig. 9 is a sectional view along the line D-D of Fig. 8;

[0022] - Fig. 10 is a sectional view along the line E-E of Fig. 8;

[0023] - Fig. 11 is a simplified block diagram relating to a possible method of processing the electrical signals produced by means of a joystick in accordance with the present invention.

[0024] In accordance with the example shown in the attached drawings, a joystick (1) made according to the present invention comprises three bodies (2, 3, 4) which are stably constrained with each other when the joystick is in the use configuration. The constraint that makes the association stable can be realized in various ways; for example, the three bodies (2, 3, 4) can be constrained with each other by mechanically forcing reciprocal mechanical interference zones (23F, 34F) to prevent their separation after assembly. Or, for example, said bodies (2, 3, 4) can be constrained with each other by means of screws, gluing, or by other suitable means. A first body or upper body (2) comprises an upper cap (2A) and a hollow lower portion (2B), inside which a group (5) is housed to which, as further described below, is attached a first magnet (50) that, in assembly configuration, is counter-faced with a Hall sensor (40). The latter is arranged on a respective printed circuit (41) fixed on a lower body (4). The reference (41) schematically represents the electronic circuit which supports the Hall sensor (40) together with the control and transformation circuits of the signals received via this sensor, circuits of a known type and which may comprise one or more microprocessors and suitable connection devices to the equipment to be controlled. In other words, at the output of the circuit (41) there are connection means (not shown in the drawings) allowing the equipment controlled by the joystick to be activated according to the signals received from the Hall sensor (40).

[0025] The upper cap (2A) of the upper body (2) has an external surface provided with crossed grooves (23) that increase the coefficient of friction externally offered by the cap itself, facilitating its use. Preferably, the upper cap (2A) is provided with a concave upper area (20) that facilitates its movement with a single finger. A grip / interaction element (not illustrated in the drawings) can also be conveniently fixed on said concave area (20) that can be differently shaped and sized according to the user's needs. The joystick's manoeuvrability can therefore be customized by applying a suitable means of interaction for the user on the concave area (20) (for example, a sphere fixed by gluing on said concave area 20).

[0026] The upper cap (2A) is provided with an internal cylindrical bushing (21), oriented radially with respect to the cap itself, in which the upper end of a rod (22) is keyed. The latter has the same orientation as the bushing (21) and, in the position shown in the attached drawings, is arranged vertically.

[0027] The rod (22) is constrained, as further described below, to a group (5) that allows the rod (22) to oscillate around two axes (x, y) that are orthogonal to each other. An extension appendix (51) is fitted on the lower end of the rod (22) which supports said first magnet (50). In practice, the force exerted by the user on the upper cap (2A) determines a corresponding oscillation of the rod (22) around the axes (x, y) and therefore the corresponding oscillation of the first magnet (50).

[0028] Ultimately, the lower body (4), the intermediate body (3) and the lower portion (2B) of the upper body (2) are stably fixed together to form a single body, with the upper cap (2A) of the upper body (2) which instead can be moved to determine, via the rod (22), the corresponding movement of the first magnet (50).

[0029] The following description concerns a possible method of realizing the aforementioned group (5).

[0030] For example, the group (5) comprises an internal pin (24) which has a hole orthogonal to the axis (x) of the internal pin itself (24), in which hole an intermediate part of the rod (22) is inserted. The two axial ends (25) of the internal pin (24) are arranged inside corresponding ball bearings (26). The bearings (26), in turn, are constrained to an external pin (27) which constitutes a housing for the internal pin (24). The external pin (27) has two opposite ends (28) arranged inside respective ball bearings (29) so as to make the external pin (27) rotatable around the axis (y) passing through its own bearings (29). In practice, the internal pin (24) is oriented orthogonally to the external pin (27), i.e. the axis (x) of the internal pin is orthogonal to the axis (y) of the external pin (27). In the exemplary configuration described above, the internal pin (24) passes internally to the external pin (27) crossing the latter transversely.

[0031] Said group (5) is arranged internally to a lower portion (2B) of the upper body (2). Below the upper body (2) is the intermediate body (3) which is provided with an upper circular flange (33) which allows the intermediate body (3) to be fixed to the upper body (2).

[0032] On the upper body (2) and on the intermediate body (3) are formed respective semicircular cavities (200, 300) in which the bearings (29) are housed. In practice, each bearing (29) is housed partly in a semicircular cavity (200) of the upper body (2) and partly in a corresponding semicircular cavity (300) of the intermediate body (3).

[0033] Therefore, depending on the force applied by the user on the cap (2A), the group (5) rotates inside the bodies (2) (3) around the axes (x) and (y). The intermediate body (3) has a circular groove in which one or more o-rings (31) are housed and is provided with a lower edge (32) which is received in a corresponding upper circular seat (400) of the lower body (4).

[0034] The lower body (4) supports a printed circuit board (41) on which the Hall sensor (40) is fixed. The latter is fixed on an upper side of the printed circuit board (41), i.e. on the side facing the unit (5). The printed circuit board (41) includes a microprocessor (410) which processes the signals coming from the Hall sensor (40).

[0035] Below the Hall sensor (40), i.e. in the lower portion of the lower body (4) and on the side opposite to the printed circuit board (41), a second magnet (6) is provided which is arranged in correspondence with the main axis (z) of the joystick (1). Said main axis (z) is arranged vertically in the drawings and corresponds to the longitudinal axis of the rod (22) in the rest position or neutral position, i.e. when the rod is not inclined for the activation of the equipment controlled by the joystick.

[0036] The arrangement of the second magnet (6) with respect to the first magnet (50), i.e. the mutual distance of these magnets (50, 6) determines the amount of force with which the rod (22) can be moved. In practice, the movement of the first magnet (50) with respect to the Hall sensor (40) which determines the activation of the equipment controlled by the joystick is subject to overcoming a resistive force due to the magnetic interaction of the two magnets (50, 6). For this purpose, the magnets (50, 6) are mutually oriented so as to present their respective N / S poles opposite each other. The movements of the first magnet (50) with respect to the Hall sensor (40) are converted into digital signals by means of the printed circuit (41) according to known conversion methods. As schematically indicated in the simplified diagram of Fig.11, the output signals from the printed circuit board (41) are intended to be converted, with methods known in themselves, into control signals of the equipment (AP) controlled by the joystick (1) by means of an external conversion unit (UC). For example, if the equipment (AP) controlled by means of the joystick (1) is the drive unit of a wheelchair for disabled people, the external conversion unit (UC) is the so-called "power module" which, as is known, controls the drive unit of the wheelchair according to the commands given by the user by means of the joystick. The second magnet (6) is fixed to a support that allows its distance from the first magnet (50) to be varied.

[0037] For example, the second magnet (6) is stably fixed in a screw element (44) provided with an external thread (43) that can be coupled with a corresponding lower internal thread of the lower body (4). In this way, it is possible to modify the position of the support element (44) by rotating it clockwise or anticlockwise. The screw element (44) is provided with a seat (45) shaped so that it can be engaged by a tool to be screwed or unscrewed with respect to the lower body (4). Preferably, said seat (45) is formed by a pair of holes in diametrically opposed positions with respect to a central axis of the screw element (44) so as to require the use of a dedicated tool, provided with two fork-like pins to be inserted into said holes, to screw or unscrew it. The use of a dedicated tool makes said adjustment more difficult to operate, reducing to a minimum the possibility that the support (44) moves spontaneously.

[0038] In this way it is possible to vary the distance between the first magnet (50) and the second magnet (6) to obtain a corresponding variation in the value of the mutual attraction force and, therefore, of the force that the user must apply to the joystick to control the controlled equipment.

[0039] The first magnet (50) can preferably be of the neodymium type.

[0040] The second magnet (6) can preferably be the same as the first one.

[0041] In accordance with the present invention, it is therefore possible to finely adjust the intensity of the force required by the user to operate the joystick in a simple and intuitive way and without replacing any part of the joystick itself.

[0042] Another feature of the present invention lies in the possibility of re-calibrating the joystick after having carried out a variation in the distance between the two magnets (50, 60).

[0043] As previously indicated, during each intervention aimed at varying the joystick actuation force, the distance between the two magnets (50, 6) is varied. The movement of the second magnet (6) determines a corresponding variation in the magnetic field generated by the magnets. This variation in the magnetic field involves a corresponding variation in the signals produced by the Hall sensor (40) which, as a consequence of the movement of the second magnet (6), is immersed in a modified magnetic field. In accordance with the present invention, an automatic recalibration software is provided in the circuit (41) serving the Hall sensor, and in particular in the microprocessor (42).

[0044] The calibration values are values used by the system to ensure that with the joystick in the neutral position the voltage or current corresponding to each output signal is equal to a pre-established value (value that the external conversion unit interprets as a neutral value, i.e. a value that does not determine any activation of the equipment connected to the conversion unit). The software provided in the circuit (41), each time the position of the magnet (6) is changed, analyses the magnetic field determined by the mutual position of the two magnets (50, 6) and identifies as the “new” zero or reference value the one provided by the Hall sensor (40) with the joystick in the “neutral” position, i.e. in the configuration in which the rod (22), the first magnet (50) and the second magnet (6) are aligned along the (z) axis.

[0045] For example, if the output voltage on a given pin of the microprocessor when the joystick shaft is in the neutral position should have a “normal” value of 1.5 V and, after having modified the geometry of the magnetic field with the movement of the second magnet (6), this value has reached 2.0 V, then by means of the software resident in the circuit (41) the output voltage on that given pin is brought back to 1.5 V.

[0046] More generally, automatic recalibration consists in automatically bringing back, after a movement of the second magnet (6) and by means of a program resident in the circuit (41), the voltage or current values on the output pins connected to the external conversion unit to predefined values corresponding to a rest or neutral condition of the joystick.

[0047] From the preceding description it is evident that a joystick in accordance with the present invention is a joystick comprising an actuation rod (22) that can be moved in relation to a respective support body (2, 3, 4) and provided with a first magnetic element (50) interacting with a Hall sensor (40) configured to produce electrical signals that can be used to control an electrically controllable device (AP) in function of the position assumed by the first magnet (50) with respect to the Hall sensor (40), wherein the movement of the activation rod (22) is determined by overcoming a resistive force provided by a respective contrast element configured to maintain the activation rod (22) in a neutral position in which the Hall sensor does not produce signals that can be used to control the device (AP), wherein said contrast element is a second magnetic element (6) arranged in said body (2, 3, 4) in a position opposite to the first magnetic element (50) with respect to the Hall sensor (40), and said second magnetic element (6) is arranged on a support (44) which allows its distance from the first magnetic element (50) to be varied.

[0048] From the preceding description it also appears evident that a joystick in accordance with the present invention can present one or more of the following additional characteristics, even combined with each other:

[0049] - said support (44) is provided with a thread (43) shaped complementarily with respect to a corresponding thread (42) provided by the body (2, 3, 4) of the joystick (1) to allow the position of the same support (44) to be adjusted with respect to the body (2, 3, 4) of the joystick (1) by means of clockwise or anticlockwise rotation.

[0050] - the joystick is provided with microprocessor self-calibration means adapted for compensating the variation in the magnetic field determined by a variation in the distance between said magnetic elements (50, 6).

[0051] - the signal coming from said Hall sensor (40) is processed by a corresponding microprocessor circuit (41) to provide output signals adapted for driving said equipment, and said self-calibration means comprise a software program resident in said microprocessor circuit suitable for bringing said output signals to pre- established values if the signal of the Hall sensor (40) relating to a pre-established configuration varies in correspondence with said variation in the distance between the magnetic elements (50, 6).

[0052] - said activation rod (22) is constrained to a group (5) comprising two pins (24, 27) oriented with their respective axes (x, y) orthogonal to each other and constrained to said body (2, 3, 4) by means of corresponding bearings (26, 29) such that the activation rod (22) can rotate around both said axes (x, y).

[0053] - one (24) of said pins (24, 27) is arranged passing transversally through the other pin (27).

[0054] - said body (2, 3, 4) is formed by several elements that delimit an internal space to the same body (2, 3, 4) in which the first magnetic element (50), the Hall sensor (40), the activation rod (22) and the second magnetic element (6) are housed.

[0055] The details of execution can however vary in an equivalent manner in the shape, dimensions, arrangement of the elements, nature of the materials used, without however departing from the scope of the idea of the solution adopted or of the inventive concept and therefore remaining within the limits of the protection granted by the patent claims.

Claims

CLAIMS1) Joystick comprising an actuation rod (22) that can be moved in relation to a respective support body (2, 3, 4) and provided with a first magnetic element (50) interacting with a Hall sensor (40) configured to produce electrical signals that can be used to control an electrically controllable device (AP) in function of the position assumed by the first magnet (50) with respect to the Hall sensor (40), wherein the movement of the activation rod (22) is determined by overcoming a resistive force provided by a respective contrast element configured to maintain the activation rod (22) in a neutral position in which the Hall sensor does not produce signals that can be used to control the device (AP), joystick characterized in that said contrast element is a second magnetic element (6) arranged in said body (2, 3, 4) in a position opposite to the first magnetic element (50) with respect to the Hall sensor (40), and said second magnetic element (6) is arranged on a support (44) which allows its distance from the first magnetic element (50) to be varied.2) Joystick according to claim 1, characterized in that said support (44) is provided with a thread (43) shaped complementarily with respect to a corresponding thread (42) provided by the body (2, 3, 4) of the joystick (1) to allow the position of the same support (44) to be adjusted with respect to the body (2, 3, 4) of the joystick (1) by means of clockwise or anticlockwise rotation.3) Joystick according to claim 1, characterized in that it is provided with microprocessor self-calibration means adapted for compensating the variation in the magnetic field determined by a variation in the distance between said magnetic elements (50, 6).4) Joystick according to claim 3, characterized in that the signal coming from said Hall sensor (40) is processed by a corresponding microprocessor circuit (41) to provide output signals adapted for driving said equipment, and said selfcalibration means comprise a software program resident in said microprocessor circuit suitable for bringing said output signals to pre-established values if the signal of the Hall sensor (40) relating to a pre-established configuration varies in correspondence with said variation in the distance between the magnetic elements (50, 6).5) Joystick according to claim 1, characterized in that said activation rod (22) is constrained to a group (5) comprising two pins (24, 27) oriented with their respective axes (x, y) orthogonal to each other and constrained to said body (2, 3, 4) by means of corresponding bearings (26, 29) such that the activation rod (22) can rotate around both said axes (x, y).6) Joystick according to claim 5, characterized in that one (24) of said pins (24, 27) is arranged passing transversally through the other pin (27).7) Joystick according to claim 1, characterized in that said body (2, 3, 4) is formed by several elements that delimit an internal space to the same body (2, 3, 4) in which the first magnetic element (50), the Hall sensor (40), the activation rod (22) and the second magnetic element (6) are housed.

Images