Patent Application
20060137942
A. Field of the Invention
The field of the present invention relates generally to locking mechanisms used to securely lock a wheelchair wheel so as to prevent movement of the wheelchair. In particular, the present invention relates to such wheelchair wheel locking mechanisms that are configured to prevent the wheel lock from being stuck in the locked condition when it is desired to move the wheelchair. Even more particularly, this invention relates to such wheelchair wheel locks that utilize a rotating pin and cam system to unlock the wheel and which provide a more compact unit when the wheelchair is folded.
B. Background
The primary purpose of a wheelchair is to provide a safe and relatively convenient means of mobility to persons who may otherwise not be mobile or have very limited mobility. The person in the wheelchair often needs or desires the wheelchair to remain stationary, for instance when he or she is getting in or out of the wheelchair. The many advances in wheelchair technology have generally resulted in wheelchairs that require less effort to move, which is very beneficial when wheelchair movement is desired but less so when the wheelchair must remain stationary. As a result, wheelchair manufacturers have had to develop improved braking and wheel locking mechanisms to stop the wheelchair or to prevent movement of the wheelchair when being stationary is desired. With regard to wheelchair wheel locking mechanisms, the mechanism must be configured to securely lock the wheelchair wheel when it is engaged so that the wheelchair does not move, particularly when the occupant of the wheelchair desires to get in or out of the wheelchair. As can be envisioned, movement of wheelchair when it is desired that it be stationary can result in potentially serious injury to the user, such as would occur from falling as he or she tries to get in or out of the wheelchair.
The use of wheelchair locking mechanisms are well known and a number of such mechanisms are described in the prior art. For example, U.S. Pat. No. 5,799,756 to Roberts, et al. describes wheelchair wheel lock comprising a slotted disc, which is mounted on the hub of a wheel, that has a plurality of tapered slots on the outer perimeter of the disc which are configured to accept a correspondingly configured tapered latch. The locking component pivots the latch into a slot to lock the wheel and then out of the slot to unlock the wheel. U.S. Pat. No. 6,308,804 to Roberts describes a wheelchair wheel lock comprising a locking disc, mounted to the wheel hub, that has a plurality of chamfered holes and a locking component that includes a spring driven tapered pin that is configured to be driven into a hole on the disc to lock the wheel in place and then withdrawn to allow movement of the wheel. U.S. Pat. No. 6,341,671 to Ebersole describes a wheelchair wheel lock comprising a hub mounted disc having a plurality of apertures and locking component that includes a spring driven plunger that is driven into one of the apertures to lock the wheel and removed therefrom to unlock the wheel. Action of a lever causes a cable interconnecting the lever and the plunger assembly to operate the plunger, which has a beveled distal end to facilitate entry into an aperture. U.S. patent application Publication No. 20040099487 to Melgarejo comprises a wheel hub mounted locking ring that has a plurality of dog receiving cages that are each provided with an opening into which a spring-driven dog, having tapered sidewalls, is inserted. In the Melgarejo mechanism the locking ring is axially aligned with the wheel hub, whereas in the forgoing patents the locking disc is generally perpendicular to the axis of the wheel hub.
Although the foregoing and other prior art wheel lock devices are generally able to suitably place a wheelchair wheel in a locked condition, they all suffer from a well known and heretofore not sufficiently addressed problem, namely that under certain conditions it is very difficult to operate the locking mechanism to unlock the wheelchair wheel. It is well known that many wheelchair users frequently desire to locate the wheelchair as close as possible to a table, bed or other object. Generally, this results in the wheel making contact with the object. When the wheelchair wheel is pushed against such an object, it can be very difficult for the wheelchair bound person to operate the locking mechanism so as to unlock the wheel and allow movement of the wheelchair. Under such circumstances, the straight action movement of the prior art wheelchair wheel locks, including those described above, often gets stuck in place due to the pressure of the side of the slot, hole, aperture or other opening (collectively, the “hole”) against the spring-driven pin, plunger, dog or other locking member (collectively, the “pin”). Because of the pressure of the wheelchair wheel against the object, the locking component cannot sufficiently move to withdraw the pin from the hole to unlock the locking mechanism and allow the desired movement of the wheel.
Another problem common with the prior art wheelchair wheel locks is that the pin driven locking mechanisms require that the pin be sufficiently spaced from the hole so that it can move in and out of the hole to lock or unlock the wheel. As a result of this spacing requirement, the typical wheelchair wheel lock effectively extends the width of the wheelchair. When the wheelchair is folded for movement or storage, the additional width resulting from the wheelchair wheel lock mechanism can be relatively significant and undesirable.
What is needed is an improved wheelchair wheel lock that solves the problem of the stuck wheelchair wheel lock that prevents unlocking of the wheel when the wheel is pushed against another object, a problem experienced by many users of wheelchairs. What is also needed is a wheelchair wheel lock that does not significantly increase the effective width of the wheelchair. The preferred wheelchair wheel lock will allow the user to easily unlock the wheel even when the wheel is pushed against an object and will reduce the width of the wheelchair for improved ease of moving or storing when folded. The preferred wheelchair wheel lock should comprise a wheel hub mounting disc having a plurality of holes thereon and a spring-driven locking pin that is disposed in a housing having a cam path in which a cam follower pin moves to move the locking pin in or out of the holes to lock or unlock the wheel. In this configuration, the locking pin is rotated in and out of the hole to lock or release the wheel hub instead of being directly driven in and out of the hole, as with the prior art wheelchair wheel locks, so as to prevent the pin being stuck in the hole when pressure is applied to the wheelchair wheel.
The wheelchair wheel lock of the present invention provides the benefits and solves the problems identified above. That is to say, the present invention discloses a wheelchair wheel lock that prevents the locking pin from getting stuck in one of the holes on the hub mounted disc by providing a mechanism that utilizes a rotation action to cause the locking pin to move into and out of the hole. The present invention also reduces the width of presently available wheelchair wheel lock assemblies so as to make it easier to move and store the folded wheelchair. The present invention is adaptable to many types of wheelchairs and can be included with a new wheelchair or adapted to retrofit an existing wheelchair.
In one general aspect of the present invention, the wheelchair wheel lock comprises a lock operating mechanism attached to the wheelchair at a place where it can be operated by an occupant of the wheelchair, a locking assembly at a wheel of the wheelchair, a cable interconnecting the lock operating mechanism with the locking assembly and a locking rotor attached to the hub of the wheel. The lock operating mechanism has a handle, which the user operates to lock or unlock the wheel, attached to a first end of the cable. The second end of the cable attaches to the locking assembly to engage or disengage the locking rotor and prevent or allow movement of the wheel. In the preferred embodiment, the locking rotor has a plurality of locking apertures and the locking assembly comprises a locking pin having a first end that engages one of the plurality of locking apertures on the locking rotor. Also in the preferred embodiment, the locking assembly further comprises a base plate positioned substantially adjacent the locking rotor, a lock stub mounted on the base plate and a lock lever pivotally engaged with the lock stub. The second end of locking pin extends through an aperture in the base plate and into the second end of the lock stub to connect with the lock lever pivotally disposed over the first end of the lock stub. The lock stub has a cam path disposed on the side thereof and the lock lever has a cam follower pin received in the cam path. The cam path is configured such that pivotal movement of the lock lever, achieved by movement of the cable due to operation by the user, will extend or retract the first end of the locking pin so that it will either engage one of the locking apertures to lock the wheel to prevent movement of the wheelchair or disengage from the locking aperture to unlock the wheel so as to allow movement of the wheelchair. In the preferred embodiment, the plane of the base plate is substantially parallel to the plane of the locking rotor and the locking pin extends substantially perpendicular from the base plate.
In a second general aspect of the present invention, the locking assembly for a wheel lock, which is configured to lock a wheel of a wheelchair, has a base plate that is attached to the frame of the wheelchair and positioned substantially adjacent to a locking rotor that is attached to a hub of the wheelchair wheel. The locking rotor has a plurality of locking apertures. A lock stub, having a first end, a second end and a cam path on the side thereof, is fixed to the base plate. A locking, pin having a first end and a second end, is disposed in the second end of the lock stub, with the first end of the locking pin configured to operatively engage one of the plurality of locking apertures on the locking rotor. A lock lever is pivotally disposed about the first end of the lock stub and connected to the second end of the locking pin. The lock lever has a cam follower pin that is in cooperative engagement with the cam path, which is shaped and configured such that movement of the cam follower pin through the cam path will engage or disengage the first end of the locking pin with one of the plurality of the locking apertures. The cam follower pin moves through the cam path due to the pivotal movement of the lock lever about the lock stub, which movement results from operation of a cable connected to a lock operating mechanism mounted on the wheelchair at a place accessible by the person seated in the wheelchair.
Accordingly, the primary objective of the present invention is to provide an improved wheelchair wheel lock that provides the advantages discussed above and overcomes the disadvantages and limitations which are associated with presently available wheelchair wheel locks.
An important objective of the present invention to provide a wheelchair wheel lock that prevents the problem of the locking mechanism being stuck in the locked condition when a wheelchair wheel is abutting an object, which is a common problem with the prior art wheelchair wheel locking mechanisms.
It is also an important objective of the present invention to provide a wheelchair wheel lock that prevents the problem of a locking pin being stuck in a hole on the wheel hub mounted rotor when a wheelchair wheel is abutting an object and it is desired to unlock the wheelchair for movement thereof.
It is also an important objective of the present invention to provide a wheelchair wheel lock that does not significantly increase the effective width of the wheelchair due to the amount of space needed to operate the wheel lock mechanism so as to not significantly increase the problems with moving or storing a folded wheelchair.
It is also an important objective of the present invention to provide a wheelchair wheel lock that utilizes a cable operated lever that engages a cam mechanism so as to rotate the locking pin in and out of receiving engagement with the locking rotor mounted to the wheel hub so as to selectively lock or unlock the wheel.
The above and other objectives of the present invention will be explained in greater detail by reference to the attached figures and the description of the preferred embodiment which follows. As set forth herein, the present invention resides in the novel features of form, construction, mode of operation and combination of processes presently described and understood by the claims.
In the drawings which illustrate the preferred embodiments and the best modes presently contemplated for carrying out the present invention:
With reference to the figures where like elements have been given like numerical designations to facilitate the reader's understanding of the present invention, the preferred embodiments of the present invention are set forth below. The enclosed figures and drawings are merely illustrative of a preferred embodiment and represents one of several different ways of configuring the present invention. Although specific components, materials, configurations and uses are illustrated, it should be understood that a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein. For purposes of this disclosure, references are generally to use of the present invention with a wheelchair, however, it is understood that the disclosure herein may apply to other types of devices having similar wheel locking needs.
A wheelchair wheel lock that is manufactured out of the components and configured pursuant to a preferred embodiment of the present invention is shown generally as 10 in
In a preferred embodiment, lock operating mechanism 18 comprises bracket 28 sized and configured to attach to an upper portion of frame 14, handle 30 pivotally attached to bracket 28 by pivot mechanism 32, cable support 34 on bracket 28 and a cable receiving aperture 36 in handle 30 for securely connecting to an upper or first end 38 of cable 22. In the embodiment shown in the
As shown in
Locking assembly 20 is configured to selective engage one of the plurality of locking apertures 54 on locking rotor 52 to place wheelchair wheel lock 10 in the locked condition. In the preferred embodiment, best shown in FIGS. 4 through 9, locking assembly 20 comprises base plate 62 having a lock stub 64 mounted thereon, lock lever 66 cooperatively engaged with lock stub 64 (as set forth in more detail below), an axle cooperating aperture 68 for receiving an outer end of axle 18 and cable stand 70 attached thereto or mounted thereon for supporting the second end 72 of cable 22. Locking assembly 20 also comprises locking pin 74 having a first end 76 sized and configured to engage one of the plurality of locking apertures 54 on locking rotor 52 and a second end 78 connected to lock lever 66 with a connecting element, such as screw 80. In the preferred embodiment, as best shown in
As best shown in
Spring 82 is disposed around the second end 78 of locking pin 74 and both are received in an opening in the second end 92 of lock stub 64 through stub aperture 122 in base plate 62. The first end 88 of lock stub 64 is received in an opening in lever body 100 of lock lever 66 and connecting element 80 connects to the second end 78 of locking pin 74 in a manner that securely holds locking pin 74 in lock stub 64, even with spring 82 biasing first end 76 away from lock stub 64, while permitting lock lever 66 to pivot about lock stub 64 so as to move cam follower pin 98 through cam path 96. As cam follower pin 98 moves through cam path 96 away from base plate 62, due to the action of handle 30 moving from locked groove 40 to unlocked groove 42, lock lever 66 will pull first end 76 of locking pin 74 away from engagement with one of the apertures of locking rotor 52, thereby unlocking wheel 16 and allowing wheelchair 12 to move. As cam follower pin 98 moves through cam path 96 towards base plate 62, due to the action of handle 30 moving from unlocked groove 42 to locked groove 40, lock lever will rotate and push first end 76 of locking pin 74 towards engagement with one of the plurality of apertures of locking rotor 52, thereby locking wheel 16 and preventing movement of wheelchair 12. This rotating movement of lock lever 66 from the movement of handle 30 results in first end 76 of locking pin 74 being moved into or out of engagement with one of the locking apertures 54 on locking rotor 52, thereby preventing the common stuck locked condition that results from direct insertion into the locking aperture or slot of existing wheelchair wheel locks. As known to those skilled in the art, the various components of wheelchair wheel lock 10 of the present invention can be made out of a variety of different materials as may be suitable for use with wheelchairs. Such materials can include metals such as aluminum, plastics, composites and a variety of other materials.
In use, the user will operate handle 30 to cause inner wire member 26 to pivot lever handle 104 of lock lever 66 and pivot lever body 100 about lock stub 64. The rotating of lever body 100 moves cam follower pin 98 inside cam path 96 to cause the force of spring 82 to bias first end 76 of locking pin 74 into one of the plurality of locking apertures 54 of locking rotor 52 to lock wheel hub 48 and prevent movement of the wheelchair wheel 16. Opposite movement of the user's lever or other device will cause inner wire member 26 to rotate lever body 100 in the opposite direction and release the pressure on locking pin 74 to withdraw first end 76 of locking pin 74 from the locking aperture 54 of locking rotor 52. Because locking pin 74 is moved by rotation action of the cam mechanism, as described above, instead of direct insertion that is utilized with the prior art devices, the first end 76 of locking pin 74 will not be stuck inside locking aperture 54 of locking rotor 52 due to the force against the wheelchair wheel 16 causing a lateral force against first end 76 of locking pin 74 (which in prior art devices prevents first end 76 being withdrawn from locking aperture 54). In addition, the wheelchair wheel lock 10 of the present invention provides a narrower profile for wheelchair 12 which will make it easier to move and store.
While there are shown and described herein a specific form of the invention, it will be readily apparent to those skilled in the art that the invention is not so limited, but is susceptible to various modifications and rearrangements in design and materials without departing from the spirit and scope of the invention. In particular, it should be noted that the present invention is subject to modification with regard to any dimensional relationships set forth herein and modifications in assembly, materials, size, shape, and use. For instance, there are numerous components described herein that can be replaced with equivalent functioning components to accomplish the objectives of the present invention.
This application claims the benefit of U.S. Provisional Application No. 60/623,377 filed Oct. 28, 2004.
| Number | Date | Country | |
|---|---|---|---|
| 60623377 | Oct 2004 | US |
