Brakes – Vehicle
Reexamination Certificate
2001-01-16
2002-10-15
Lavinder, Jack (Department: 3613)
Brakes
Vehicle
Reexamination Certificate
active
06464044
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a braking apparatus for braking rotation of a wheel of a wheelchair, handcart or other vehicle. More particularly, the invention relates to a braking apparatus for use with a wheel covered at its outer periphery with a tire which is formed of a rubber or other elastic material, wherein the braking apparatus includes a member that is brought into contact with the tire, for thereby braking rotation of the wheel.
2. Discussion of Related Art
Most of conventional braking apparatuses used for wheelchairs have been designed to completely inhibit movement of the wheelchair by locking wheels of the wheelchairs. In view of a recently increasing utilization of wheelchairs in various kinds of fields, there is proposed an improved braking apparatus, e.g., a braking apparatus which is additionally equipped with a mechanism for preventing a backward movement of a wheelchair in an upslope, as disclosed in JP-A-7-227408. However, the conventional braking apparatuses including the braking apparatus disclosed in the Japanese publication have complicated constructions, and do not have sufficiently high degree of durability and maneuverability. That is, the conventional braking apparatuses should be further improved to overcome these drawbacks. Conventional braking apparatuses used for other vehicles such as handcarts carrying a person or goods have the same drawbacks to be overcome.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a braking apparatus which is improved in at least one of simplification of construction, service life and maneuverability.
The above object may be achieved according to any one of the following modes of the present invention, each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate and clarify possible combinations of elements or technical features. It is to be understood that the present invention is not limited to the technical features or any combinations thereof which will be described for illustrative purpose only. It is to be further understood that a plurality of elements or features included in any one of the following modes of the invention are not necessarily provided all together, and that the invention may be embodied without some of the elements or features described with respect to the same mode.
(1) A braking apparatus for braking a wheel of a vehicle, comprising:
a main body;
a cam which is supported by the main body such that the cam is rotatable about an axis thereof, and which has a cam surface whose distance from the axis changes as viewed in a circumferential direction of the cam;
a movable member which is held by the main body such that the movable member is movable relative to the main body, and which holds a cam follower portion engaging the cam surface, and a braking portion brought into contact with a tire of the wheel; and
an operating device which includes an operating member operable to be moved in first and second directions, and which rotates the cam in one of opposite directions in response to the movement of the operating member in the first direction, for thereby moving the movable member in a forward direction that causes the braking portion to be displaced toward the tire, and rotates the cam in the other of the opposite directions in response to the movement of the operating member in the second direction, for thereby moving the movable member in a reverse direction that is opposite to the forward direction.
When the operating member is operated to be moved in the first direction in the braking apparatus according to mode (1) of this invention, the cam is rotated in one of the opposite directions in response to the movement of the operating member in the first movement, and the movable member engaged at the cam follower portion with the cam surface is moved in the forward direction as a result of the rotation of the cam in the above-described one of the opposite directions, so that the braking portion of the movable member is forced against the tire of the wheel, whereby rotation of the wheel is braked. In this instance, the movable member is moved with a sufficiently large force owing to a boosting function provided by the cam surface of the cam. When the operating member is operated to be moved in the second direction in the present braking apparatus, the movable member is moved in the reverse direction as a result of the rotation of the cam in the other of the opposite directions, so that the braking portion is separated from the tire of the wheel. The mechanism used in the present braking apparatus for moving the movable member is simplified as described above, thereby making it possible to manufacture the braking apparatus in a reduced cost.
Where a grooved cam or other positive-return cam is used as the above-defined cam in the present braking apparatus, the movable member can be positively moved in the reverse direction as well as in the forward direction, by the movement of the operating member. Where a plate cam or other non-positive-return cam is used as the cam, a suitable device for returning or reversely moving the movable member is preferably provided in the present braking apparatus. The suitable device may be, for example, adapted to bias the movable member in the reveres direction whereby the movable member is moved in the reverse direction in response to the movement of the operating member in the second direction, for thereby releasing the engagement of the braking portion with the tire of the wheel.
(2) A braking apparatus according to mode (1), further comprising a reverse-movement preventing device which prevents the movement of the movable member in the reverse direction.
In the vehicle equipped with braking apparatus of this mode (2), even if an user or operator releases the operating member while the vehicle is being braked by the braking apparatus, the braking apparatus is held in its working state so that the vehicle keeps to be braked by the braking apparatus. Thus, this arrangement further improves the maneuverability of the braking apparatus.
(3) A braking apparatus according to mode (2), wherein the reverse-movement preventing device includes a positioning device which positions the movable member in a selected one of a plurality of predetermined positions relative to the main body, and holds the movable member in the selected position.
In the braking apparatus of this mode (3), the movable member is positioned and then held in a selected one of the plurality of positions, by the positioning device. The plurality of positions may be determined on the basis of an operating state of the braking apparatus. For example, where the plurality of positions consists of three positions (i.e., first, second, third positions), the three positions may be determined so as to respectively correspond to a braking state, a reverse-rotation inhibiting state and a non-working state of the braking apparatus. Described more specifically, the three positions may be determined such that (a) the braking apparatus is placed in the braking state in which the wheel is braked by the braking apparatus, when the movable member is positioned in the first position, (b) the braking apparatus is placed in the reverse-rotation inhibiting state in which reverse rotation of the wheel is inhibited or braked by the braking apparatus while forward rotation of the wheel is permitted, when the movable member is positioned in the second positioned, and (c) the braking apparatus is placed in the non-working state in which the wheel is not braked by the braking apparatus, when the movable member is positioned in the third position.
The three positions may be determined also on the basis of a working state of the braking apparatus, namely, on the basis of an amount of braking force applied to the wheel by the braking apparatus. In this case, the three positions may be determined so as to correspond to a strongly braking state, a moderately braking state and
Lavinder Jack
Oliff & Berridg,e PLC
Takahiro Engineering Works Ltd.
Torres Melanie
LandOfFree
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