Patent Application
20060163437
1. Field of the Invention
The present invention relates to a connecting device, and more particularly to a four-bar linkage that holds a joystick controller in a constant orientation.
2. Description of Related Art
Electric wheelchairs are a convenient mode of transportation for patients, aged people or handicapped people because they can go anywhere by moving a joystick without assistance from other people.
A conventional electric wheelchair has a seat, two arms, a joystick and a connecting device attached to one arm and the joystick. The connecting device is a rod pivotally connecting the joystick to the arm so that the joystick extends out from the arm. By pivoting the connecting device, the joystick can move aside to keep the joystick from bumping against objects when a user moves close to a table or a wall. However, the orientation of the joystick changes when the connecting device pivots relatively to the electric wheelchair. Consequently, adjusting the direction of movement of the joystick after every movement of the connecting device is inconvenient.
To overcome the shortcomings, the present invention provides an improved connecting device for a joystick controller on an electric wheelchair to obviate the aforementioned problems.
The main objective of the invention is to provide a connecting device that keeps a joystick connected to the connecting device from changing its operational orientation.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
A connecting device for a joystick controller on an electric wheelchair in accordance with the present invention comprises a post, two rods and a base. The post has two brackets attached to the post. The two rods are pivotally attached respectively to the two brackets in parallel with each other. The base pivotally attached to the two rods forms a four-bar linkage with the two rods and the post. The joystick controller is adjustably and detachably mounted on the base. The four-bar linkage keeps the joystick controller oriented in a constant direction when the base moves relatively to the electric wheelchair. Therefore, the joystick controller has a fixed orientation relative to the wheelchair.
With reference to FIGS. 1 to 3, a preferred embodiment of the connecting device in accordance with the present invention attaches a joystick controller (40) to an arm of an electric wheelchair (1) and comprises a post (10), two rods (20) and a base (30).
The post (10) is attached under an arm of an electric wheelchair, is a rectangular tube and has a front face, an outer face, two brackets (102) and two pivot pins (104). The two brackets (102) are attached respectively to the front face and the outer face in a single horizontal plane. Thus, the two brackets (102) are oriented perpendicular to each other. Each bracket (102) is U-shaped, has a cross member and two wings and is attached to the post (102) at the cross member so the wings protrude out from the post (10). Each wing of the bracket (102) has a hole, and the holes on the two wings are aligned with each other. The pivot pins (104) are mounted through the holes respectively in the two brackets (102).
Each rod (20) has a proximal end, a distal end, a length and two transverse end sleeves (22). The two rods (20) are the same length and are pivotally attached respectively to the two brackets (102) on the post (10) in parallel to attach to the base (30). The transverse end sleeves (22) are formed respectively at the proximal end and the distal end. Each transverse end sleeve (22) has a top, a bottom and two bushings (202) mounted respectively on the top and bottom. The transverse end sleeve (22) at the proximal end is aligned with the holes in the two wings and mounted pivotally between the two wings of one corresponding bracket (102) with the pivot pin (104).
The base (30) is connected pivotally to the distal ends of the two rods (20), is a rectangular panel and has four corners, a top face, a rear edge, a front edge, an inner edge, an outer edge, two mounting holes (302), two pivot pins (308), multiple adjustment holes, a U-shaped mounting bracket (304), a T-connector (32), multiple fasteners and a knob (34).
The two mounting holes (302) are formed diagonally through the base (30) respectively at the corner between the rear edge and the outer edge and the corner between the front edge and the inner edge.
The pivot pins (308) extend respectively through the mounting holes (302) and pivotally attach the transverse end sleeves (22) at the distal ends of the rods (20) to the base (30). Therefore, the two mounting holes (302) in the base (30), the two rods (20) and the two brackets (102) on the post (10) define a four-bar linkage.
The adjustment holes are formed in a line through the base (30) parallel to the outer edge near the front edge.
The U-shaped mounting bracket (304) is attached to the top face of the base (30) and has multiple through holes (306) and a channel. The through holes (306) are defined through the U-shaped mounting bracket (304), communicate with the channel and respectively correspond to align with the adjustment holes in the base (30).
The T-shaped connector (32) has a crossbar, a longitudinal adjustment leg, three attachment holes (322) and two fasteners. The crossbar has two ends. Two attachment holes (322) are formed through the crossbar respectively near the two ends, and the other attachment hole (322) is formed through the longitudinal adjustment leg. The T-connector (32) is attached to the joystick controller (40) by fasteners that pass through the attachment holes (322) on the crossbar and detachably attach to the joystick controller (40). The longitudinal adjustment leg is mounted in the channel in the U-shaped mounting bracket (304). The attachment hole (322) through the longitudinal adjustment leg is selectively aligned with a through hole (306) in the U-shaped mounting bracket (304) to accommodate a particular user. Then, the knob (34) screws through the U-shaped mounting bracket (304) and the attachment hole (322) to attach the T-connector (32) and the joystick controller (40) to the base (30).
With reference to FIGS. 4 to 7, the four-bar linkage of the connecting device maintains the same orientation of the joystick controller (40) even when the base (30) is moved relatively to the wheelchair. Therefore, operation of the joystick controller (40) results in the same relative movement of the wheelchair. Moreover, transportation of the electric wheelchair is convenient because the joystick controller (40) is detachable from the base (30) by disengaging the knob (34) in a convenient way.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
