TECHNICAL FIELD

The invention relates to a locking system for attaching and locking a panel to a frame.

BACKGROUND OF THE INVENTION

It is sometimes necessary to attach a panel to a frame, particularly when attaching a backrest panel to a wheelchair frame or when attaching a seat pan panel to a wheelchair frame. It is also sometimes necessary to remove such panels from frames. When the frame is a wheelchair frame, it is important that the backrest and seat pans are safely locked in position before a user sits in the wheelchair. Because the backrest and seat pan may be repeatedly removed for cleaning or for adjustment and refitting, it is useful to provide a simple and effective system of locking and releasing such a panel to a wheelchair frame.

It is therefore an object of the invention to provide a locking system that is adapted to allow a panel to be locked to a frame and to be released from the frame, or to at least provide a useful alternative to existing locking systems. SUMMARY OF THE INVENTION

In a first aspect, the invention provides a locking system to attach a panel to a frame, wherein the locking system comprises: a panel comprising at least one keyhole aperture and a locking aperture; and at least one lock adapted to be attached to a frame and comprising a first locking member adapted to engage with and retract from a respective keyhole aperture in the panel and a second locking member adapted to engage with and retract from a respective locking aperture in the panel.

In one form, the panel comprises opposing side edges and at least one keyhole aperture and a locking aperture are provided near each side edge.

Preferably, a plurality of keyhole apertures and locking apertures extend in a line near each side edge of the panel.

Preferably, the keyhole apertures and locking apertures are equidistant from the side edges of the panel.

Preferably, each keyhole aperture is paired with a corresponding locking aperture and wherein the distance between each paired keyhole aperture and locking aperture is consistent.

In one form, the lock comprises a lock housing in which the first and second locking members are partially housed. Preferably, the lock housing comprises a first surface from which the first and second locking members extend when the lock is in a locked position, and wherein the lock housing also comprises a substantially opposing second surface.

Preferably, the second surface comprises a locking recess and the second locking member comprises a lock actuator, and wherein the locking recess is shaped to receive at least a portion of the lock actuator when the second locking member is in a locked position.

In one form, the lock housing also comprises an attachment surface extending between the first and second surfaces, the attachment surface comprising a substantially u- shaped channel for receiving a portion of a frame member therein.

In another form, the locking system further comprises a clamping member, adapted to be attached to the lock housing, the clamping member having an attachment surface comprising a substantially u-shaped channel for receiving a portion of a frame member therein

Preferably, the first and second locking members are biased to a locked position. In one form, the first locking member comprises a cam lever adapted to lock and unlock the first locking member.

Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field.

The term "comprising" as used in this specification means "consisting at least in part of". When interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE FIGURES

Preferred embodiments of the invention will be described by way of example only and with reference to the drawings, in which :

Figure 1 is a top view of a seat pan panel of one form of the invention;

Figure 2 is a perspective view of the underside of the seat pan of Figure 1 ;

Figure 3 is an exploded perspective view of one form of lock for use with the locking system of the invention ; Figure 4 is an exploded perspective view of another form of lock for use with the locking system of the invention;

Figure 5A is a side view of the lock of Figure 4 in a locked position;

Figure 5B is a cross-sectional view of the lock of Figure 5A taken along line A-A;

Figure 5C is a side view of the lock of Figure 4 in an unlocked position;

Figure 5D is a cross-sectional view of the lock of Figure 5C taken along line B-B;

Figure 5E is a perspective view of a locking system comprising the lock of Figure 4 in an unlocked position;

Figure 5F is a perspective view of a locking system comprising the lock of Figure 4 in an locked position;

Figure 6 is an exploded perspective view of another form of lock for use with the locking system of the invention ;

Figure 7 is a side view of the lock of Figure 6;

Figure 8 is another side view of the lock of Figure 6;

Figure 9 is an exploded perspective view of locks to be attached to a frame according to one form of the invention;

Figure 10 is a perspective view of locking systems according to one form of the invention fitted to a frame;

Figure 11 is a side view of the locking systems and frame shown in Figure 9;

Figure 12 is a top view of a seat pan attached to a chair frame using a locking system of one form of the invention ;

Figure 13 is a side view of the attached chair frame and seat pan of Figure 12;

Figure 14 is a front view of the attached chair frame and seat pan of Figure 12; and

Figure 15 is a perspective view of the attached chair frame and seat pan of Figure 12.

DETAILED DESCRIPTION

The invention relates to a locking system for attaching a panel to a frame. For the purposes of exemplification only, the invention is illustrated and described in relation to attaching a seat pan to a chair frame, such as a wheelchair frame or pushchair frame. However, it should be appreciated that the invention could also be used to attach a backrest to a chair frame, or the invention could be used in any other suitable situation where the invention can be usefully employed to attach a panel to a frame.

The locking system of the invention comprises a panel and a lock. The lock is adapted to attach to a frame member. The panel is adapted to engage with at least one locking member of the lock to attach the panel to the frame member.

Figures 1 and 2 show one form of panel for use with the locking system of the invention. The panel 100 has a first edge 110, a second edge 120, and two side edges 130a, 130b extending between the first and second edges 110, 120. The panel 100 comprises at least one keyhole aperture 140 and at least one locking aperture 150. In one form, the panel comprises a plurality of keyhole and locking apertures extending in a line near each side edge of the panel. Preferably, as shown in Figure 1, a plurality of keyhole and locking apertures are alternately positioned in a line that is substantially adjacent to and parallel with a first side edge 130a, and a plurality of keyhole and locking apertures are alternately positioned in a line that is substantially adjacent to and parallel with a second side edge 130b.

Each keyhole aperture is an oblong shape having a width or circumference at a first end of the keyhole that is greater than the width or circumference of the opposing second end.

In the embodiment shown in Figures 1 and 2, each keyhole aperture 140 is formed from two substantially circular apertures partially overlaying each other to form an oblong aperture having a first circumference at the first end and a second circumference at the second end. The first circumference is larger than the second and a neck is formed between the two circular regions.

In another form, the keyhole may be formed from two square shapes, the square at the first end having a larger width than the square at the second end. In yet another form, the keyhole aperture may be substantially ovoid.

Figure 3 shows one form of lock 200 for use with the locking system of the invention.

The lock comprises a lock housing 210 having a first surface 211 that substantially faces toward the panel in use, an opposing second surface 212, and a contact surface 213 extending between the first and second surface. In the embodiment shown in Figures 3 to 13, the contact surface 213 extends along one side of the lock housing. The lock also comprises a first locking member 220 that is adapted to be received at least partially within a first aperture 214 formed in the lock housing 210. The first locking member comprises a first locking head 221 and a body 222. The first locking head is located at a first end of the locking member body 222. The locking head 221 is adapted to project from the first surface 211 of the lock housing so that, when in a locked position, the head 221 projects from the first surface 211 of the lock housing at a distance greater than the distance at which the head 221 projects from the housing when the lock is in an unlocked position. In some forms, the first locking head may not project from the housing at all when in an unlocked position.

The body 222 of the first locking member 220 may be substantially elongate. The locking member body is adapted to be held at least partially within the first aperture 214 formed in the lock housing and is able to slide at least partially in and out of the aperture 214 as the locking member moves between the locked and unlocked positions. In one form, the locking head may have a width or circumference greater than the width or circumference of the locking member body. The shape and size of the locking head is such that it can fit through the first end of the keyhole aperture but not through the second end of the keyhole aperture. The shape and size of the locking member body is such that it can fit through both the first and second ends of the keyhole aperture.

The lock may be biased to the locked position by a biasing system.

In the embodiments shown in Figures 3 and 4, the locking member body 222 comprises a substantially cylindrical rod comprising a substantially disc shaped locking head

221 at a first end of the body.

Although in the embodiments illustrated, the locking member body and head together form a substantially cylindrical rod, it should be appreciated that the rod may be of any suitable shape. For example, the lateral cross-section of the rod may be substantially hexagonal, octagonal, quadrilateral, triangular, oval, or of any other suitable shape.

In one form, the locking head of the first locking member 220 may be integrally formed with the locking member body 222, such that the locking member body 222 comprises an elongate rod in which the diameter or width of the locking head is substantially equal to the diameter or width of the locking member body.

The second end of the locking member body 222 may be directly or indirectly engaged with a first lock actuator.

In the embodiment shown in Figure 3, the second end of the locking member body

222 is engaged with one end of a first biasing system in the form of a spring 300a, engages with the first lock actuator.

In the embodiment shown in Figure 4, a biasing system in the form of a spring 300a engages with the locking head 221 of the first locking member 220 and a shelf 216 formed in the lock receiving aperture of the lock housing 210. The biasing system is configured to bias the first locking member 220 to a locked position by pressing against both an underside of the locking head 221 and the shelf 216 of the lock receiving aperture, as shown in Figures 5B and 5D.

A first lock actuator in the form of a lever 400 may be provided at the second surface of the lock housing 200 to move the first locking member from a locked position to an unlocked position and vice versa.

In one embodiment, as shown in Figure 3, the lever 400 comprises a cam 410 at its hinged end that contacts the other end of the spring 300a, so that when the lock is assembled, the spring is sandwiched between the locking member 220 and the cam 410 of the lever. In one embodiment, the cam is adapted to provide a non-moving support aperture 411 in which an end of the spring can be held. In this form, the support aperture 411 is formed within a mounting block 412 that is attached to or integral with the lever 400. A contact surface of the cam rotates beneath the aperture as the lever rotates about its pivot point. In this arrangement, one end of the spring is in contact with the contact surface of the cam and the sides of the spring are at least partially supported by the walls of the support aperture 411. A handle 420 is provided at the other end of the lever.

By lifting the handle of the lever 400 away from the lock housing 200, the lever is caused to pivot, causing the cam to rotate. As the cam 410 rotates and an area of the cam with a smaller diameter aligns with the support aperture 411, the spring 300a is caused to move in a direction away from the first surface 211 of the lock housing 200. In effect, when the locking system is used to attach a seat pan to a chair, the spring is caused to move downwardly by lifting the handle of the lever away from the lock housing . As the spring 300a moves away from the first surface of the lock housing, the locking member 220 is pulled toward the housing 200. Consequently, the locking head 221 is pulled toward (or into) the housing 200 to reach an unlocked position.

In another embodiment, as shown in Figure 4 and 5A to 5F, the lever 400 comprises a cam 410 that engages with a second end of the first locking member body 222 at a pivot point 450 so that the lever 400 is able to rotate about the second end of the locking member, as shown in Figures 5A to 5F. For example, the second end of the first locking member body 222 may comprise a pivot point 450 in the form of an axle that engages with the cam lever and about which the cam lever can rotate. In one form, as shown in Figure 5, the lever 400 comprises a handle 420 at a first end and a cam 410 at a second end substantially opposing the first end. The cam 410 may comprise a substantially u-shaped portion in which the arms of the U are configured to engage with the first locking member body 220. For example, the arms of the U may each comprise an aperture 415 that aligns with an aperture 215 formed in the second end of the first locking member body 220. An axle 460 may be configured to project through the aligned apertures 415, 215 to connect the cam 410 to the first locking member body 220 in a pivoting arrangement.

In one form, the cam is configured so that the distance between the pivot point 450 and the distal ends of the arms of the U is less than the distance between the pivot point and the second end of the lever 400. In this configuration, when the lever 400 is positioned so that the distal ends of the arms of the U abut the second surface of the lock housing 200, the pivot point 450 is closer to the second surface of the lock housing 200 than when the lever is positioned so that the second end of the lever 400 abuts the second surface of the lock housing 200. Where the lever 400 is rotated to cause the pivot point 450 to move closer to the second surface of the lock housing 200, the locking head 221 of the first locking member 220 is caused extend away from the first surface 211 of the lock housing to form a locked position, as shown in Figures 5A, 5B and 5F. Conversely, when the lever 400 is rotated to cause the pivot point 450 to move away from the second surface of the lock housing 200, the locking head 221 of the first locking member is caused to retract toward or into the lock housing to form an unlocked position, as shown in Figures 5C, 5D and 5E. In the embodiment shown in Figures 4 to 8, the lock 200 comprises a second locking member 230 comprising a second locking head 231, a second body 232, and a second spring biasing system 300b. A second lock actuator 500 is also provided.

In one embodiment, the second locking member body 232 may be released from or held in a locked position by a second lock actuator 500 in the form of any suitable fastener, such as a nut 500, as shown in Figure 4. For example, the second locking head 231 may be positioned to project above the first surface of the lock housing in the locked position and may be caused to clamp down on top of a panel, such as a seat pan, and to be held in place by tightening the nut 500 against a second end of the second locking member body, which may extend from the second surface of the lock housing. In the embodiment illustrated, the second locking member 232 is released from the locked position by releasing the nut 500.

Again, the second locking member may comprise a biasing system to bias the second locking member to a locked position. In one form, the biasing system comprises a spring 300b that engages with the second locking member 320 and a shelf 217 formed in the lock receiving aperture of the lock housing 210. In one form, the biasing system is configured to bias the second locking member 320 to a locked position by pressing against both an underside of the locking head 321 and the shelf 216 of the lock receiving aperture, as shown in Figures 5B and 5D.

In the embodiment shown in Figures 6 to 8, the second lock actuator is configured to cause the second locking member to move to an unlocked position by retracting and rotating the second lock actuator away from the lock housing.

In this embodiment, the lock housing 210 comprises a second aperture 215 in which a portion of the second locking member body 232 is received. The second locking head 231 is provided at a first end of the second locking member body and the opposing second end of the locking member body is engaged with a biasing system in the form of a spring 300b.

The second locking head is adapted to project above the first surface of the lock housing. In particular, when in a locked position, the second head projects from the first surface of the lock housing at a distance greater than the distance at which the second head projects from the housing when the lock is in an unlocked position. In some forms, the second locking head may not project from the lock housing at all when in an unlocked position.

The second locking member body 232 is adapted to slide at least partially in and out of the second aperture 215 as the second locking member moves between the locked and unlocked positions.

The second surface 212 of the lock housing comprises a female key member aperture.

The lock actuator 500 comprises a male key member 510 that is shaped and sized to fit within the key member aperture in one orientation but not in another orientation when rotated in the same plane. In other words, the key member and key member aperture are configured so that the male key member will not fit within the female key member aperture if not aligned with each other. The male key member can be moved in and out of alignment with the female key member aperture by rotating the male key member in one plane. For example, in the embodiment shown in Figure 6, the male key member is an oblong shape and the female key member aperture is the same oblong shape. In one orientation, the male key member fits within the female key member aperture. However, if the male key member is rotated 90 degrees so that it no longer aligns with the female key member aperture, the key member cannot fit within the key member aperture.

The male key member 510 is engaged with one end of the second spring 300b.

By rotating the second lock actuator 500 to align the male key member 510 with the female key member aperture on the second surface of the lock housing, the male key member is able to nest within the key member aperture, which causes a contact surface of the male key member to push against the spring 300b. The spring 300b in turn pushes against the second end of the locking member 232, causing the locking head 231 to move away from the first surface of the housing 210 to reach a locked position.

To release the male key member from the key member aperture, the lock actuator 500 can be retracted and turned so that the male key member is retracted from the key member aperture and no longer aligns with that aperture. When the male key member is retracted from the key member aperture, the second spring 300b is pulled into the key member aperture, pulling the second locking member further into the lock housing so that the second locking head is pulled toward (or into) the housing to reach the unlocked position.

The lock housing 210 can be attached to a frame member 600 using any suitable attachment system.

In one form, the contact surface 213 of the lock housing 210 may be adapted to receive a portion of a frame member 600 therein. In the embodiment shown in Figure 8, the contact surface 213 of the lock housing comprises a substantially u-shaped channel to receive a portion of a substantially cylindrical frame member 600 therein. The u-shaped channel is positioned so that the longitudinal axis of a frame member received within the channel will be substantially parallel to the first surface 211 of the lock housing.

In this form, the locking system may also comprise a clamping member 700 having a first surface 710 comprising a substantially u-shaped channel, as shown in Figure 9.

To attach the lock housing 210 to a frame member 600, the contact surface 213 of the lock housing is positioned to abut the frame member 600 and the first surface 710 of the clamping member 700 is also positioned to abut the opposing side of the frame member, so that the frame member 600 extends between the u-shaped channels of the lock housing and clamping member. The lock housing 210 and clamping member 700 are then removably attached together by any suitable attachment system so that the lock can be attached to and detached from a frame member. For example, the two parts may be screwed together or attached with a nut and bolt arrangement 720, as shown in Figure 9. In another example, the lock housing and clamping member may be hinged together at one end to substantially wrap around the frame member. In this form, the lock housing and clamping member are removably attached together at the other end so that the two parts can be clamped onto and detached from the frame member.

In the embodiment shown in Figure 9, the lock housing and clamping member may be loosely attached to each other to allow the lock housing to slide along the frame member to a desired location before the lock housing and clamping member are firmly attached together to hold the position of the lock housing on the frame.

Where the locking system is used to attach a seat pan panel to the frame of a chair, such as a wheelchair, as shown in Figures 10 and 11, at least two, and preferably four, locks are attached to the appropriate frame members of the chair frame. The lock housings are preferably attached so that the lever handles face toward the front of the chair for easy access. However, it should be appreciated that the lock housings may be attached in any suitable orientation. For example, two lock housings at the rear of the chair may be oriented so that the levers face the rear and two lock housings at the front of the chair may be oriented so that the levers face the front of the chair.

Once the locks are attached to the frame, the panel can be positioned adjacent the frame so that the locking head of the first locking member of each lock aligns with the first end of a respective keyhole. The locking heads are then pushed through the first end of the keyhole and the panel is slid in the direction of the second end of the keyhole to cause the body of each of the first locking members to slide along the keyhole and to be received within the smaller second end of the keyhole. The first locking head is too large to fit through the second, smaller end of the keyhole and therefore the first locking member cannot be disengaged from the keyhole in this position. The only way to disengage the locking member from the keyhole is to slide the panel in the opposite direction to cause the first locking member to move toward the first end of the keyhole at which point the first locking head can be retracted from the keyhole.

The panel and locks are adapted so that when the first locking member body reaches the second, smaller end of the keyhole, each of the second locking members align with a respective locking aperture. The lock actuator for the second locking member is then rotated until the key member aligns with and is received within the key member aperture. The key member pushes against the second spring, which pushes the second locking member toward the panel so that the second locking head projects through the locking aperture to reach the locked position. The second locking member fits snugly within the locking aperture to prevent the panel from sliding significantly with respect to the frame. In this position, the panel is locked to the frame, as shown in Figure 12 to 15. Each of the first locking members cannot be slid within or removed from the respective keyhole in the panel until the second locking members are retracted from the respective locking apertures.

To detach the panel from the frame, each lock is unlocked by retracting the key members from the respective key member apertures and rotating each key member so that it no longer aligns with the respective key member aperture. The levers of the first locking members are then released and the panel is slid along the frame to cause each of the first locking members to move into the first end of the respective keyhole aperture. The panel can then be lifted away from the frame by allowing the locking head of each of the fi rst locking members to pass through the respective keyhole aperture.

In one form, as shown in Figure 13, a locking housing having two locking members (as shown in Figure 6) is attached at each side of the front of the chair frame and a lock housing having only one locking member (as shown in Figure 3) is attached at each side of the rear of the chair frame. In this arrangement, it is possible to disengage the front locks from the seat pan and to pivot the pan slightly upward and toward the rear of the seat before disengaging the rear locks.

Although the invention has been described and illustrated for use when attaching a seat pan panel to a chair frame, the invention may also be used to attach a backrest panel to a chair frame using the same methods as described above.

The locking system of the invention offers a quick way of locking a panel to a frame and of releasing the panel from the frame. The locking system is particularly advantageous when attaching a seat pan to a chair frame because it is possible for a user to locate the seat pan on the frame in the required location and to then simply push down on the seat pan from above to lock the seat pan in place.

One or more of the components and functions illustrated in the figures may be rearranged and/or combined into a single component or embodied in several components without departing from the invention. Additional elements or components may also be added without departing from the invention.

Although the invention has been described by way of example, it should be appreciated that variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.