A joystick

Abstract: The invention relates to a joystick having a hand-grip, which is mounted with two degrees of freedom in a mounting in a housing and which may be deflected in different directions out of an initial position, the grip being biased by a spring mechanism towards its initial position and sensor apparatus being provided to sense the different positions of the grip and to generate an output signal which may be used to control machine and/or vehicle functions. A housing cover (5) is provided having its upper side directed towards the grip, while on the underside, there is pivotally mounted a cardan joint centre portion (6) on whose underside there is pivotally mounted a cardan joint inner portion (7), whose underside is provided with spherical segments, which are mounted in complementary bearing cup-portions provided on a receiving support (8).

Description: The present invention relates to a joystick according to the preamble of claim 1. As regards the mounting, use may be made of a ball-and socket joint or a cardan joint. A cardan joint comprises three joint portions, which are pivotally connected by means of guides. These guides consist of a large number of individual parts. Moreover, the effort required for assembly is great. Ball-and-socket joints have three degrees of freedom. However, in the case of joysticks, rotation about the grip axis is not required. On that account, such rotation is prevented by a pin which is fastened to the socket and engages in a vertical groove in the ball. This arrangement, however, is susceptible to wear and is only capable of bearing light stresses. A joystick having the features of the preamble of claim 1 is known from US-A-5 619 195 according to which the cardan joint inner portion is formed just like a ring and is described as being pivotally connected with the cardan joint centre portion of the multi-dimensional position sensing apparatus only. The problem on which the present invention is based is to provide a joystick which overcomes or mitigates the aforementioned disadvantages. In particular, it is desirable that the joystick should be economic to manufacture and easy to install and should increase robustness of the assembly. In regard to a joystick having a grip, which is mounted with two degrees of freedom in a mounting in a housing and which may be deflected in different directions out of an initial position, the grip being biased by a spring mechanism back towards its initial position and in which the different positions of the grip are sensed by sensor apparatus which outputs a signal which is used to control machine and/or vehicle functions, it is proposed that on the underside of a housing cover which has its upper side directed towards the grip, there should be pivotally mounted a cardan joint centre portion on whose underside there is pivotally mounted a cardan joint inner portion, whose underside is provided with spherical segments, which are mounted in complementary bearing cup-portions provided on a receiving support. In regard to the device according to the invention, there may be employed a cardan joint in which the bottom half is cut away. Because of this, the joint can easily be assembled by engaging the parts together. The receiving support prevents the elements of the cardan joint from coming apart. A particular embodiment of the invention is according to claim 2 characterised in that on the side of the cardan joint inner portion which is directed away from the grip, there is provided a magnet whose movement is recorded by a sensor carried by a printed-circuit board which is mounted in the housing. By this means it is readily guaranteed that the deflection of the grip will be accurately sensed. In addition, the number of individual parts of the joystick is kept small. Another particular embodiment of the invention is according to claim 3 characterised in that the grip comprises a grip tube having a stop for a spring, which is biased against a plate which engages on the housing cover. The spring ensures that after the grip is deflected, it is restored to its initial position. The joint portions are pulled upwards by the force of the spring. Another particular embodiment of the invention is according to claim 4 characterised in that the deflection region of the joystick comprises a first region, in which the restoring force of the grip increases only comparatively slightly, and a second so-called dwell-pressure region in which the grip, having passed a pressure-point, can move a little further, and in that at least one arcuately shaped leaf spring is fastened to the grip tube with the aid of a mounting. In one known device, a spring-mounted locking ram is fastened to each axis. This locking ram is pressed by a spring against a ramp fastened to the housing. The behaviour of the grip during return to its position can be influenced by the shape of the ramp. The restoring force of the grip changes as a function of the angle of the ramp in relation to the direction of movement of the ram. This conventional solution requires a separation of the axes of movement of the grip. Moreover, it is necessary to provide space for the ramp in the vicinity of the axes of movement. The assembly dimensions of tha joystick are increased because of this. These disadvantages are avoided in one particular embodiment of the invention, by means of an arcuately shaped leaf spring which may be attached to the grip tube. Moreover, the invention makes it possible to manage with fewer individual parts than is the case in known devices. A further particular embodiment of the invention is according to claim 5 characterised in that in the mounting, a recess is provided for the purpose of receiving the deformed leaf spring. The movement of the spring may then be limited by the size of the recess. Deformation of the spring in the reverse direction is prevented by this limitation of the movement of the spring. Another particular embodiment of the invention is according to claim 6 characterised in that the deflection region of the joystick comprises a first region, in which the restoring force of the grip increases only comparatively slightly, and a second so-called dwell-pressure region in which the grip, having passed a pressure point, can move a little further, and in that on the grip, there is displaceably mounted at least one spring-biased ram which cooperates with a detent contour provided at the edge of a connecting member, which detent contour limits the deflection of the grip. The geometric configuration of the detent contour may be chosen so as to determine whether the grip will engage in the end position or will spring back. Other advantages, features and details of the invention are disclosed in the following description, given with reference to the drawings, in which different embodiments of the invention are shown, by way of example only. In this connection, the features mentioned in the description and in the appended claims may be relevant to the invention either individually or in combination. In the drawings: - Figure 1 is an exploded perspective view of a joystick according to a first embodiment of the invention; Figure 2 is a longitudinal sectional view through the joystick shown in Fig. 1; Figure 3 is a longitudinal sectional view through the joystick shown in Fig. 1, displaced through 90° relative to the representation shown in Fig. 2; Figure 4 shows a longitudinal section through a joystick according to a second embodiment of the invention; and Figure 5 shows a longitudinal section through a joystick according to a third embodiment of the invention. The joystick shown in Figs. 1 to 3 comprises a tube 1, which carries a hand-grip which is not shown in the drawings. The grip tube 1 serves to receive a ring 2 which, when in position on the grip tube 1, forms a stop for a spring 4. The spring (represented only in Figs. 2 and 3) is pressed against a plate 3. The plate 3 engages against a cover 5, which forms part of a housing which surrounds the articulated mounting of the grip tube 1. On the underside of the housing cover 5 there are provided two semi-cylindrical shaped recesses, of which one is identified by the reference number 10 in Fig. 1. The semi-cylindrical shaped recesses 10 serve to receive bearing pins 11 and 12, which are formed on the centre portion 6 of a cardan joint. By this means it is provided that the cardan joint centre portion 6 may tilt about an axis which passes longitudinally through the bearing pins 11 and 12. Two semi-cylindrical shaped recesses 13 and 14 are provided on the underside of the cardan joint centre portion 6, offset through 90° in relation to the bearing pins 11 and 12. The semi-cylindrical shaped recesses 13 and 14 serve to receive two bearing pins 15 and 16 which are provided on the inner portion 7 of the cardan joint. As is to be seen in Figs. 2 and 3, the cardan joint inner portion 7 is formed with spherical segments. The spherical segments serve for mounting the cardan joint inner portion 7 in a receiving support 8. For this purpose, bearing cup-portions complementary to the spherical sections of the cardan joint inner portion 7 are constructed in the receiving support 8. The receiving support 8, which is formed with an internal opening extending through it, rests on a printed-circuit board 9. Into the opening of the receiving support 8 there extends a magnet in the shape of a right parallelepiped which is formed on the cardan joint inner portion 7. In the assembled state, the grip tube 1 extends through the cardan joint inner portion 7. The cardan joint inner portion 7 is fastened to the grip tube 1 by a pin. Because of this, it is provided that the cardan joint inner portion 7 shall execute the same movements as the grip tube 1. After deflection of the grip tube 1, the spring 4 ensures that the grip tube 1 is restored to its initial position. The spring 4 engages by means of the plate 3 against the housing cover 5. The joint is a cardan joint in which the bottom half is cut away. The recesses serving as bearing points in the cardan shaft centre portion 6 and the cardan shaft inner portion 7 are open to the bottom. Because of this, the joint can easily be assembled by engaging the parts together. The individual joint portions are pulled upwards by the force of the spring 4. This prevents the components of the joint from coming apart. However, it would be possible to press the joint downwards by overcoming the spring force. This is prevented by the receiving support 8, which supports the joint from underneath. Sensing of the position of the grip is achieved by Hall sensors which are arranged on the printed-circuit board 9. These Hall sensors react to the position of the magnet which is provided on the inner portion 7 of the cardan joint. In Fig. 4, a joystick is shown which has two different regions of deflection. In the first region, the restoring force of the grip increases only slightly. A stop should be noticeable at the end of this region. In the second region, the grip should move onwards a little, following application of a substantial force. At the end of the second region, a digital signal is generated. The restoring force of the grip should decrease again after a sharp rise. In the case of the joystick shown in Fig. 4, the pressure function between the two deflection regions is achieved by an arcuately biased leaf spring 60, which is fastened by means of a support 62 to the grip tube 61 of the joystick. On the housing 65 of the joystick there is fastened a connecting member 67 which limits the deflection of the grip tube 61. The leaf spring 60 is arched outwards away from the grip tube 61. At a particular deflection of the grip tube 61, the leaf spring 50 touches the edge of the connecting member 67. Upon further deflection of the grip tube 61, the spring force of the leaf spring 60 must be overcome. The spring force of the leaf spring 60 which acts against a further deflection increases until the leaf spring 60 is deflected in the region of the edge of the connecting link 67, into a recess 63 which is provided on the support 62. The resilient deformation the leaf spring 60 is limited by this means. Without such limitation of its deformation the leaf spring 60 might be deformed so far that the deformation at its lower end would become greater than the deformation at its upper end. In such a case, the deformation of the leaf spring 60 would be reversed. It could not then spring back of its own accord out of the reversed position. In regard to the joystick shown in Fig. 5, a ram 72 for each direction of deflection is mounted displaceably on the grip tube 71. The ram 72 is biased by a spring 73. The travel of the ram 72 is limited by stops. The tip of the ram 72 cooperates with the edge of a connecting member 74. The edge of the connecting member 74 has a particular contour, which may be identified by the angles α and β. The ram is spring-deflected as a function of the angle α, by which means the deflecting force of the grip tube 71 is increased. When the ram 72 is moved over the edge of the detent contour of the connecting member 74, the force falls off again. The magnitude of the angle β determines whether the grip tube 71 will engage in the end position or will spring back.

Claims: A joystick having a hand-grip which is mounted with two degrees of freedom in a mounting in a housing and which may be deflected in different directions out of an initial position, the grip being biased by a spring mechanism (4) towards its initial position and sensor apparatus being provided to sense the different positions of the grip and to generate an output which may be used to control machine and/or vehicle functions, and a housing cover (5) having its upper side directed towards the grip, while on the underside there is pivotally mounted a cardan joint centre portion (6) on whose underside there is pivotally mounted a cardan joint inner portion (7), characterised in that the underside of the cardan joint inner portion (7) is provided with spherical segments which are mounted in complementary bearing cup-portions provided on a receiving support (8). The joystick according to Claim 1, characterised in that on the side of the cardan joint inner portion (7) which is directed away from the grip, there is provided a magnet, a sensor being provided on a printed circuit board (9) which is mounted in the housing, to sense movement of the magnet. The joystick according to either of Claims 1 or 2, characterised in that the grip comprises a grip tube (1) having a stop for a spring (4), which is biased against a plate (3) which engages on the housing cover (5). The joystick according to any one of the preceding claims, characterised in that the deflection region of the joystick comprises a first region, in which the restoring force of the grip increases only comparatively slightly, and a second so-called dwell-pressure region in which the grip, having a pressure-point, can move a little further, and in that at least one arcuately shaped leaf spring (60) is fastened to the grip tube (61) with the aid of a mounting (62). The joystick according to Claim 4, characterised in that in the mounting (62), a recess (63) is provided for the purpose of receiving the deformed leaf spring (60). A joystick according to any one of Claims 1 to 3, characterised in that the deflection region of the joystick comprises a first region, in which the restoring force of the grip increases only comparatively slightly, and a second so-called dwell-pressure region in which the grip, having passed a pressure-point, can move a little further, and in that on the grip, there is displaceably mounted at least one spring-biased ram (72) which cooperates with a detent contour provided at the edge of a connecting member (74), which detent contour limits the deflection of the grip.

Inventors: GILLMANN UWE, KROSCHKE HENNING, LAMM KLAUS, SEMMELROGGEN WILLI, STOFFERS MICHAEL, GILLMANN, UWE, KROSCHKE, HENNING, LAMM, KLAUS, SEMMELROGGEN, WILLI, STOFFERS, MICHAEL
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 1999
Main classification: G05G9
IPC codes: G05G9