The present invention pertains to maneuverability improvements to personal transporters including self-propelled wheelchairs.
Personal transporters that may be used by handicapped persons, may be self-propelled and user-guidable, and, further, may entail stabilization in one or more of the fore-aft or lateral planes, such as when no more than two wheels are in surface contact at a time. More particularly, such transporters may include one or more clusters of wheels, with wheels in each cluster capable of being motor-driven independently of the cluster in its entirety. One example of such a transporter is described in a patent to Kamen et al., U.S. Pat. No. 5,701,965, which is incorporated herein by reference. The utility of such transporters often depends on the transporter's maneuverability and weight since these transporters frequently need to carry users in confined spaces and for extended periods of time subject to limited battery charges.
The first embodiment of the invention is a transporter for carrying a payload over a surface. The transporter includes a surface-contacting module, a power base and a support for a payload. The power base is pivotally coupled to the surface-contacting module and the support is pivotally coupled to the power base. The surface-contacting module to which the present invention refers contains at least two surface-contacting elements, such as wheels, and also any structure, such as a cluster arm, for supporting those surface-contacting elements that are in contact with the surface at any particular instant. The power base serves to mechanically couple the surface-contacting module to the payload support. As the power base pivots with respect to the surface-contacting module, the height of the support over the surface changes. The support pivots in a direction opposite to the pivoting of the power base, the support remaining substantially parallel to the surface.
In a further embodiment of the invention, a rest is included to stabilize the payload with respect to the support. The rest is pivotally coupled to the support. In a specific embodiment of the invention, the rest is a footrest for a passenger on the transporter and the support includes a seat for the passenger. The rest is pivotally coupled to the support and power base through a four-bar linkage. In another embodiment, the rest coupled to the support and the powerbase, includes a follower, such as a roller follower, that is fixed with respect to the rest and movable with respect to the power base. The follower transfers part of the load from the rest to the support and/or the power base. The four-bar linkage transfers part of the load from the rest to support and to the powerbase through the lifting arm. The load transfer permits the power base to absorb some of the “shock” which would otherwise need to be borne wholly by the rest or the support, during a front impact to the rest.
In a further specific embodiment of the invention wherein the rest includes a follower, the power base is shaped so that the angle the rest makes with a vertical plane is determined by the rotation of the power base. This rest angle remains constant as the power base rotates until a specific power base rotation angle is attained. The specific angle corresponds to a minimum height of the support above the surface. When the power base is rotated beyond the specific angle, the rest tucks towards the power base. The increased height above the surface of the support and the rest allows the “tucked” rest to continue to clear the surface. This embodiment and the embodiment with the four-bar linkage, advantageously increases the maneuverability of the transporter by tucking the rest inward towards the ground contacting elements, thus, reducing the swing radius of the transporter.
In another specific embodiment of the invention, dual footrests are provided. The control mechanism linking the support height to the rotation of the power base, through the four-bar linkage, can differ for each footrest. Accordingly, it is possible to have independent control mechanisms for each footrest. Alternatively, when using the footrest with a follower, the profile of the power base, where the followers for the respective footrests contact the base can differ for each of the two footrests. This power base profile allows the tucking behavior of one footrest to be tailored differently from the behavior of the other footrest.
In another specific embodiment of the invention, a separate and independent motor is provided to drive a footrest. The motor can drive the coupled footrest to correspondingly move with respect to the power base or support height. With dual footrests, separate and independent motors can provide independent control of each footrest, thus, the footrests correspondingly move with respect to the power base or support height. Accordingly, the motors can enable separate and independent tucking movements for each footrest.
The foregoing features of the invention will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:
Referring to
Kamen '965, column 3, line 55 through column 5, line 44, describes a mechanism and process for automatically balanced operation of wheelchair 10 in an operating position that is unstable with respect to tipping when the motorized drive arrangement is not powered.
Referring further to
As shown in
Further, as shown in
A stop 98 may be provided to inhibit rotation of the footrest past a specified angle to the vertical plane, facilitating rider comfort. In a preferred embodiment with a stop, when the transporter hits an obstacle, the force is transferred to the support 20. This force transfer may result in a better distribution of the load. In an alternate embodiment, the stop can be placed on either the support 20, at the point where the footrest is coupled to the support, or on the power base of the device.
In an alternate embodiment as shown in
In another embodiment of the invention, dual footrests are provided. Each footrest is pivotally coupled 95 to the support 20, rotating about an axis that is substantially parallel to the surface. In a preferred dual footrests embodiment, individual linkages 90 and the corresponding four-bar linkages, are pivotally coupled to each footrest and the power base. In an alternate embodiment with followers, the individual followers 90A are rigidly coupled to each footrest and movably coupled to the power base through each follower's guide wheel 92A. The profile of the power base where the guide wheels of the followers contact the base can differ for each of the footrests. In the dual footrests embodiment, the control mechanism for each of the footrests may differ and thus the footrests may operate independently. In this embodiment, one footrest may tuck towards the power base differently than the other as the support is raised above this surface. This embodiment can be used advantageously, for example, to reduce the radius about which the footrest swings if one leg of a user differs from the other. Examples of this situation would be for amputees or users with a leg in a cast.
In another embodiment, the footrest 80 is pivotally coupled 95 to the support 20, rotating about an axis that is also parallel to the surface. The footrest may have an independent motor driving it. The motor may drive the footrest to correspondingly move with the support height. In this embodiment, each footrest can have a separate motor as described above to enable independent control of the footrest correspondingly move with the support height. Such independent movements may also achieve the advantages of the dual footrests embodiment described above.
While the description of the preceding embodiments have described the transporter as a self-balancing wheelchair, the described embodiments are intended to be merely exemplary and numerous variations and modifications will be apparent to those skilled in the art. For example, the transporter need not be self-balancing and may include surface-contacting elements that stabilize the transporter to tipping in a fore-aft or lateral plane at substantially all times, e.g., a four wheeled wheelchair. The support may not include a seat for a passenger, but may include other devices for supporting a payload. The rest may be any device that tends to stabilize the payload with respect to the support.
Other variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.