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Title:
FOLDABLE WALKER WITH LOCKING MECHANISM
Document Type and Number:
WIPO Patent Application WO/1999/017707
Kind Code:
A1
Abstract:
A foldable walker (10) including a locking mechanism (26) for selectively locking the walker (10) in the open, operational position and permitting it to be folded in a closed, storage position. The foldable walker (10) includes a pair of inverted U-shaped sides (12), a front center brace (18) interconnecting the U-shaped sides (12) and a pair of side braces (20). The locking mechanism (26) is secured to each inverted U-shaped side (12) of the walker (10) and includes means (28) for selectively locking the sides (12) in the open, operational position and selectively unlocking each inverted U-shaped side (12) from its locked open position and folding them against the front center brace (18) in a closed storage position. The locking mechanism (26) also includes integral means for maintaining the sides (12) in the unlocked position and is designed to prevent accidental unlocking, while at the same time allowing single hand operation of the locking mechanism (26) in a manner that requires very little dexterity. The foldable walker (10) may also include a molded front center brace (18) and a pair of molded side braces (20) which are inexpensively manufactured and easily assembled on the walker (10). The foldable walker (10) provides a sturdy walker which includes an easily operated locking mechanism (26) for allowing the user to quickly fold and unfold the walker (10) as desired.

Inventors:
Kloiber, Daniel M. (205 Monarch Drive Peachtree City, GA, 30269, US)
Krauss, Wayne J. (157 Willis Road Sharpsburg, GA, 30277, US)
Bidwell, Christopher C. (1009 Dunbar Drive Dunwoody, GA, 30338, US)
Covault, Andrew J. (7615 Southwold Court Cumming, GA, 30041, US)
Application Number:
PCT/US1998/021131
Publication Date:
April 15, 1999
Filing Date:
October 06, 1998
Export Citation:
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Assignee:
TREK MEDICAL (6170 Brookhollow Parkway Norcross, GA, 30071, US)
Kloiber, Daniel M. (205 Monarch Drive Peachtree City, GA, 30269, US)
Krauss, Wayne J. (157 Willis Road Sharpsburg, GA, 30277, US)
Bidwell, Christopher C. (1009 Dunbar Drive Dunwoody, GA, 30338, US)
Covault, Andrew J. (7615 Southwold Court Cumming, GA, 30041, US)
International Classes:
A61H3/00; (IPC1-7): A61H3/00; A45B9/00
Foreign References:
US5529425A
US5586830A
US5579793A
US3688789A
US5275187A
US5188139A
US5862825A
Attorney, Agent or Firm:
Pratt, John S. (Kilpatrick Stockton LLP Suite 2800 1100 Peachtree Street Atlanta, GA, 30309-4530, US)
Download PDF:
Claims:
We claim:
1. A locking mechanism for selectively locking a tubular member in a fixed position, relative to a coaxial tubular member, the locking mechanism comprising: a. a first locking element; b. a second locking element adapted to receive the first locking element; c. wherein the first and second locking elements have interfitting gears for interlocking engagement with each other, the first locking element being movable relative to the second locking element; d. means for selectively moving the first locking element, relative to the second locking element, between a locked, fixed position and an unlocked, rotatable position; and e. integral means for selectively maintaining the first locking element in the unlocked, rotatable position.
2. The locking mechanism of claim 1, wherein the first locking element comprises an inner cylindrical component having an upper portion and a lower portion, the upper portion including a plurality of projecting teeth and wherein the second locking element comprises an outer cylindrical component having a plurality of complementary channels for receiving and engaging the projecting teeth of the inner cylindrical component in interlocking engagement with the outer cylindrical component.
3. The locking mechanism of claim 2, wherein the means for selectively moving the first locking element comprises a rotatable lever in communication with the inner cylindrical component, the lever defining a release for moving the inner cylindrical component from the locked position to the disengaged unlocked position by applying downward pressure on the lever.
4. The locking mechanism of claim 3, wherein the means for selectively moving the first locking element further comprises at least one actuator pin extending outward from the upper portion of the inner cylindrical component and in communication with the lever.
5. The locking mechanism of claim 4, wherein the lever comprises an outer end, an inner end and a body having a through hole extending through the body and wherein the inner end further includes a ring having at least one pin hole adapted to receive the actuator pin, the actuator pin extending through the pin hole to connect the inner cylindrical component and the lever for raising the inner cylindrical component when pressure is applied to the lever to disengage the projecting teeth from the channels.
6. The locking mechanism of claim 5, further comprising a hollow cover having a top section, a middle section and a bottom section, the top section including a top opening and the bottom section including a bottom rim and a bottom opening for receiving the inner cylindrical component in the cover.
7. The locking mechanism of claim 6, wherein the cover includes at least one vertical slot extending from the middle section through the bottom section of the cover, the slot having a closed, top end and an open, bottom end extending through the bottom opening of the cover and wherein the open bottom end is adapted to receive the actuator pin into the slot and the closed top end defines a stop for limiting the vertical movement of the actuator pin and the inner cylindrical component.
8. The locking mechanism of claim 7, wherein the cover further includes a platform extending from the cover on which the lever pivots.
9. The locking mechanism of claim 8, wherein the ring is positioned over the cover and the cover is positioned over the inner cylindrical component, the actuator pin extending outward through the pin hole of the ring and the lever rests and pivots on the platform when downward pressure is applied to the lever.
10. The locking mechanism of claim tu, wherein the cylindrical component ismovable in the slot between a first position, wherein the actuator pin is near the open bottom end of the slot and the ring is resting on the bottom rim, and a second, raised position wherein the ring is raised in response to downward pressure on the lever and the actuator pin contacts the closed, top end of the slot.
11. The locking mechanism of claim 2, wherein the outer cylindrical component has top and bottom edges and the complementary channels are defined by a plurality of vertical projections extending from the top edge to the bottom edge and including at least one short vertical projection extending from the bottom edge and stopping short of the top edge.
12. The locking mechanism of claim 11, wherein the integral means comprises a ledge having a top side, the ledge formed by the short vertical projection.
13. The locking mechanism of claim 12, wherein the plurality of projecting teeth on the upper portion of the inner cylindrical component include a deep projecting tooth having a long portion extending beyond the upper portion through the lower portion of the inner cylindrical component.
14. The locking mechanism of claim 13, wherein the deep projecting tooth further includes a shoulder adjacent to the long portion, the shoulder having a bottom edge and extending through the upper portion to the same length as the plurality of projecting teeth.
15. The locking mechanism of claim 14, wherein the shoulder rests on the top side of the ledge and the long portion is positioned within the channel as the inner cylindrical component is in the fixed, locked position and wherein the long portion contacts the top side of the ledge as the inner cylindrical component is in the unlocked, rotatable position for maintaining the inner cylindrical component in the unlocked, rotatable position.
16. The locking mechanism of claim 13, wherein the long portion engages the adjacent vertical projection of the plurality of vertical projections as the inner cylindrical component is in the unlocked, rotatable position to prevent the inner cylindrical component from rotating in an outward, direction.
17. A foldable walker comprising: a. a pair of inverted, Ushaped sides, each side having a front leg tube and a rear leg tube; b. a front center brace extending between and connecting the inverted, Ushaped sides together; c. a locking mechanism for locking the sides in an open, operational position and selectively unlocking the sides for folding them against the front center brace in a closed, storage position; and d. a pivotable paddle mounted on each inverted, Ushaped side for actuating the locking mechanism.
18. The foldable walker of claim 17, the locking mechanism comprising: a. a first locking element; b. a second locking element adapted to receive the first locking element; c. wherein the first and second locking elements have interfitting gears for interlocking engagement with each other, the first locking element being movable relative to the second locking element; d. means for selectively moving the first locking element, relative to the second locking element, between a locked, fixed position and an unlocked, rotatable position; and e. integral means for selectively maintaining the first locking element in the unlocked, rotatable position.
19. The foldable walker of claim 18, wherein the first locking element comprises an inner bushing gear and the second locking element comprises an outer cylindrical component.
20. The foldable walker of claim 19, wherein the front center brace has opposite ends including a tube collar at each end, each tube collar is positioned on a front leg and has a top portion.
21. The foldable walker of claim 20, wherein the outer cylindrical component is integral with the top portion.
22. The foldable walker of claim 21, wherein the inner bushing gear has an upper portion and a lower portion, the upper portion including a plurality of splines and wherein the top portion of the tube collar includes a plurality of internal splines to define a plurality of complementary channels for receiving and engaging the splines of the inner bushing gear in interlocking engagement with the tube collar.
23. The foldable walker of claim 22, wherein the rotatable paddle is in communication with the inner bushing gear, the paddle defining a release for moving the inner bushing gear from the locked position to the disengaged unlocked position by applying downward pressure on the paddle.
24. The foldable walker of claim 23, wherein the means for selectively moving the first locking element comprises at least one actuator pin extending outward from the upper portion of the inner bushing gear and in communication with the paddle.
25. The foldable walker of claim 24, wherein the paddle further comprises a rotatable, cylindrical collar connected to the paddle, the collar having at least one actuator pin hole and wherein the paddle extends from the collar and has an outer end, an inner end and a body having a through hole extending through the body, the paddle for raising the inner bushing gear pressure is applied to the paddle to disengage the splines from the channels.
26. The foldable walker of claim 25, the locking mechanism further comprising an upper locking clip having a top section, a middle section and a bottom section, the top section including a top opening and the bottom section including a bottom rim and a bottom opening for receiving the inner bushing gear in the upper locking clip.
27. The foldable walker of claim 26, wherein the upper locking clip includes at least one vertical slot extending from the middle section through the bottom section of the clip, the slot having a closed, top end and an open, bottom end extending through the bottom opening of the clip and wherein the open bottom end is adapted to receive the actuator pin into the slot and the closed top end defines a stop for limiting the vertical movement of the actuator pin and the inner bushing gear.
28. The foldable walker of claim 27, wherein the cover further includes a platform extending from the cover.
29. The foldable walker of claim 28, wherein the cylindrical collar is positioned over the clip and the clip is positioned over the inner bushing gear, the actuator pin extends outward through the pin hole of the collar and the paddle pivots on the platform when downward pressure is applied to the paddle.
30. The foldable walker of claim 29, wherein the inner bushing gear is movable in the slot between a first position, wherein the actuator pin is near the open bottom end of the slot and the collar is resting on the bottom rim, and a second, raised position wherein the collar is raised in response to downward pressure on the paddle and the actuator pin contacts the closed, top end of the slot.
31. The foldable walker of claim 22, wherein the top portion of the tube collar has top and bottom edges and the complementary channels are defined by a plurality of vertical splines extending from the top edge to the bottom edge and including at least one short vertical spline extending from the bottom edge and stopping short of the top edge.
32. The foldable walker of claim 31, wherein the integral means comprises a ledge having a top side, the ledge formed by the short vertical spline.
33. The foldable walker of claim 32, wherein the plurality of splines on the upper portion of the inner bushing gear include a deep projecting tooth having a long portion extending beyond the upper portion through the lower portion of the inner bushing gear.
34. The foldable walker of claim 33, wherein the deep projecting tooth further includes a shoulder adjacent to the long portion, the shoulder having a bottom edge and extending through the upper portion to the same length as the plurality of splines.
35. The foldable walker of claim 34, wherein the shoulder rests on the top side of the ledge and the long portion is positioned within the channel as the inner bushing gear is in the fixed, locked position and wherein the long portion contacts the top side of the ledge as the inner bushing gear is in the unlocked, rotatable position for maintaining the inner bushing gear in the unlocked, rotatable position for folding the sides in the closed, storage position.
36. The foldable walker of claim 33, wherein the long portion engages the adjacent vertical projection of the plurality of vertical projections as the inner bushing gear is in the unlocked, rotatable position to prevent the inner bushing gear from rotating in an outward, direction and prevent the sides from inadvertently pivoting outward.
37. The foldable walker of claim 17, wherein the front center brace comprises molded polypropylene.
38. The foldable walker of claim 17, further comprising a side brace mounted on each inverted, Ushaped side and extending between the front and rear leg tubes.
39. The foldable walker of claim 38, wherein the side brace is glass filled nylon.
40. A foldable walker comprising: a. a pair of inverted, Ushaped sides, each side having a front leg tube and a rear leg tube; b. a front brace having two opposed ends, each of which ends connects to one of the front leg tubes; c. a locking mechanism associated with each front leg tube and the connected end of the front brace and comprising interfitting, gear like teeth alternatively positionable so that the side is: i. locked in an oper, operational position or ii. unlocked in a folded, nonoperational position; and d. a pivotable paddle positioned generally within each inverted, Ushaped side for unlocking the locking mechanism by depressing the paddle.
Description:
FOLDABLE WALKER WITH LOCKING MECHANISM REFERENCE TO PRIOR APPLICATIONS This application contains the subject matter of United States provisional patent application number 60/061,349 filed October 8,1997, the entire contents of which application is incorporated herein by this reference, and to which application priority is hereby claimed.

BACKGROUND OF THE INVENTION This invention relates to foldable walkers and a locking mechanism for use with such walkers. Foldable walkers are well known and widely used by persons such as frail elderly persons, who need support when standing and walking, yet wish to conveniently store the walker when it is not in use. While there are numerous foldable walkers with various locking devices for folding the walker, many of the prior locking devices are difficult to operate and require substantial dexterity or two hands to operate. Alternatively, if a locking device is easily activated, then it may be inadvertently activated or may not be reliably secured. This is a disadvantage to persons using foldable walkers who rely on the walker for support and may be seriously injured if the walker were to collapse accidentally. Another disadvantage of prior foldable walkers is the tendency for the locking device to break or wear out quickly. In an effort to provide lightweight yet sturdy and inexpensive walkers, there has been a continuing move toward lighter weight materials. However, prior foldable walkers require the manufacture and assembly of several components, and the locking device is often a separate, additional component which may increase the weight and the expense of manufacturing the walker.

SUMMARY OF THE INVENTION This invention is a foldable walker for use by persons who need support when standing and walking, such as frail elderly persons. The foldable walker includes locking mechanisms which are easily unlocked for folding the walker into a closed storage position, yet reliably secured when locked for maintaining the walker in the open, operational position. A pair of inverted U-shaped sides, each having a front and back leg, are each reinforced by a side brace between the front and back legs, and the two front legs are connected by a front center brace.

The locking mechanisms are secured to each inverted U-shaped side of the walker for locking the sides in the open, operational position and selectively unlocking each inverted U-shaped side from its locked open position so it can be folded against the front center brace in a closed, storage position. The lock is designed to prevent accidental unlocking by requiring a two step release process, while at the same time allowing single hand operation of the locking mechanism in a manner that requires very little dexterity.

The lock includes a first locking element and a second compatible, coaxially aligned, locking element designed to be selectively secul ed to each other in an interlocking relationship.

The first and second locking elements include interfitting gears for interlocking engagement with each other. In order to operate the locking mechanism between an engaged, locked position and a disengaged, unlocked position, a paddle moves the first locking element relative to the second locking element. The locking mechanism also includes an integral means for maintaining the locking elements in the unlocked position. _ Unlike prior walkers which typically include two or more tubes in front, the front center brace of the present invention is molded from a single piece of durable plastic and thus is inexpensive to manufacture and simple to assemble. The front center brace has opposite ends which each include a tube collar adapted to be positioned on the front leg of each side of the walker and a center cross beam which extends between the tube collars. When assembled, the front center brace connects and secures the inverted U-shaped sides together to provide a sturdy walker. The tube collar includes a locking element (further described below) which receives a compatible locking element for selectively locking the walker in the open, operational position and permitting it to be folded in a closed, storage position. A one-piece molded side brace is secured to the front and back legs of each side c, the walker. Like the molded center brace, the molded side braces are inexpensively manufactured and easily assembled. Minimizing the number of pieces required to construct the walker, provides a foldable walker which is less expensive to manufacture and easily assembled, yet is sturdy, has increased strength and includes an easily operated locking mechanism for allowing the user to quickly fold and unfold the walker as desired.

In the preferred embodiment, the first locking element is an inner bushing gear secured to a front leg of the walker, which includes a plurality of projecting teeth and is movable by rotating

the walker side relative to the front brace between a fixed, locked position and a folded, unlocked position. The second locking element is the front brace tube collar internally channeled to receive the projecting teeth of the inner bushing gear. In the assembled walker, the locking mechanism is secured in the open, locked position by inserting the inner bushing gear into the tube collar and rotating it such that the interfitting teeth and channels are aligned and engage one another. The locking mechanism is easily unlocked by partially withdrawing the inner bushing gear from the tube collar to disengage the gears to a rotatable, unlocked position and pivoting the inner bushing gear to contact the integral means for maintaining the locking mechanism in the unlocked position and folding the walker.

The inner bushing gear is actuated by a paddle or lever to disengage each inverted U- shaped side from its locked, open position to permit it to be folded against the front brace. In the preferred embodiment, the means for actuating the inner bushing gear include the paddle and a pair of actuator trunnions on the inner bushing gear which are in communication with the paddle.

Each paddle is rotatably positioned near the top of each inverted U-shaped side and is easily accessible by the user. In order to actuate the inner bushing gear to unlock it, downward pressure is applied to the paddle with a single hand to raise the corresponding trunnions. When the trunnions are raised, the inner bushing gear is partially withdrawn from the tube collar and the interlocking gears are disengaged. While continuing to apply downward pressure, the user pulls each paddle (or the associated walker side) in an inward direction toward the user, which pivots the inner bushing gear to fold the sides of the walker against the front center brace.

When the paddles are pressed and pulled inward so that the inner bushing gear is disengaged and pivoted, a uniquely configured deep tooth of the inner bushing gear contacts a surface between the channels of the tube collar and forces the inner bushing gear to remain in the disengaged, unlocked position. To ready the walker for use, the sides are unfolded to the open position causing the disengaged inner bushing gear to pivot so that the portion loses contact with the raised section and the interfitting gears fall into their normally interlocking relationship in the engaged, locked position. In the preferred embodiment, the integral means also provides a stop for preventing a pressed paddle from inadvertently pivoting outward which would cause the corresponding side to swing out away from the user, which would be undesirable. Thus, the stop provides a safety feature which permits the unlocked inner bushing gear to pivot only in an

inward direction ensuring that the unlocked sides of the walker are folded inward against the front center brace.

It is thus an object of this invention to provide a foldable walker with inverted U-shaped sides and a readily actuated locking mechanism which permits the user to easily disengage the inverted U-shaped sides from a locked, open position and fold them into a closed, storage position.

It is a further object of this invention to provide a locking mechanism which includes a locking means designed to prevent accidental unlocking by requiring a two step process to release the locking means, while at the same time allowing single hand operation of the locking mechanism in a manner that requires very little dexterity.

It is another object of this invention to provide a locking mechanism which includes a first locking element and a second compatible locking element with interfitting gears designed to be selectively secured to each other in an interlocking relationship.

It is another object of this invention to provide a locking mechanism which includes a locking element actuated by applying downward pressure to a paddle to disengage the inverted U-shaped side from its locked, open position and permit it to be folded into a closed storage position.

It is a further object of this invention to provide a locking mechanism which includes an integral means for selectively maintaining the locking elements in a disengaged, unlocked position to keep the inverted U-shaped sides in their closed, folded position.

It is yet another object of this invention to provide a foldable walker which is inexpensively manufactured and easily assembled.

It is another object of this invention to provide a foldable walker which includes a molded, unitary front center brace for securing the inverted U-shaped sides to each other and molded, unitary side braces extending between the legs of each inverted U-shaped side for stabilizing the structure of the walker.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the foldable walker of this invention including a locking mechanism and showing the inverted U-shaped sides in the open, operational position.

Figure 2 is a perspective view of the foldable walker with the inverted U-shaped sides in the closed, folded position.

Figure 3 is an exploded perspective view of a portion of the front center brace and the locking mechanism showing the various components of the locking mechanism.

Figure 4 is a top plan view of a paddle and inner bushing gear that is actuated by the paddle to disengage an inverted U-shaped side from its locked, open position to permit it to be folded against the front brace.

Figure 5 is a side elevation view of a portion of the locking mechanism, shown partly in section to illustrate hidden portions of those components.

DETAILED DESCRIPTION OF THE DRAWINGS Foldable walker 10 is illustrated in Figs. 1 and 2 in an open, operational position and in a folded, storage position, respectively. The foldable walker 10 includes a pair of inverted U- shaped sides 12 each having a front leg tube 14 and a rear leg tube 16, a front center brace 18 and a pair of side braces 20. The front center brace 18 includes a cross beam 22 and has opposite ends each including a hollow tube collar 24 which is positioned on one of the front leg tubes 14 of each inverted U-shaped side 12 to interconnect the inverted U-shaped sides 12. A ring 88 mounted on the front leg tube 14 of each inverted U-shaped side 12 below the tube collar 24 secures the tube collar in place by preventing it from moving down the leg tubes 14. Ring 88 includes a top side 90 adapted to fit against the bottom of tube collar 24. As may be seen in Fig.

3, ring 88 is held in position by a button 92 received in a hole in tube 14; button 92 is locked in position by collar 106 that fits inside ring 88 to prevent withdrawal of button 92.

In the preferred embodiment, the sides 12 and front and rear leg tubes 14,16 are constructed from a lightweight, durable metal such as steel (which may be painted) or aluminum (which may be anodized). The foldable walker 10 features a locking mechanism 26 which is secured to each inverted U-shaped side 12 and includes means for locking the sides 12 in the open, operational position and selectively unlocking them to permit the sides 12 to be folded against the front center brace 18 in a closed storage position as shown in Fig. 2. In the preferred embodiment, the locking mechanism 26 includes a pivotable paddle 28 which is positioned near the top of each inverted U-shaped side 12, where it is readily accessible and easily operated by the user (see Figs. 1 and 2). The locking mechanism 26 includes a locking mechanism which is

unlocked by applying downward pressure on the paddle 28 and pulling the pressed paddle or the U-shaped side 12 in toward the user in a manner which allows single handed use and requires very little dexterity.

The locking mechanism includes first and second locking elements with interfitting gears for selectively securing the inverted U-shaped sides 12 in a open, locked position for use and a closed, unlocked position for storing the walker 10. In the preferred embodiment, the first locking element is an inner bushing gear or inner cylindrical component 30 and the second locking element is an outer cylindrical component 32 are positioned on a coaxially aligned with and adapted to receive the inner cylindrical component 30. Each of the cylindrical components 30,32 are positioned on a front leg tube 14 of one of the inverted U-shaped sides 12. As can be seen by reference to Fig. 3, the outer cylindrical component 32 of the preferred embodiment defines and is integral with a top portion of each tube collar 24, one of which is located at each end of the front center brace 18.

As illustrated in Fig. 3, the inner cylindrical component 30 has a lower portion 34, and an upper portion 36 with a top end 38 which includes a plurality of splines or vertically projecting teeth 40 along the upper portion 36. The outer cylindrical component 32 has a plurality of internal vertical projections and thus is internally splined to form a plurality of complementary channels 42 for receiving and circumferentially engaging the projecting teeth 40 of the inner cylindrical component 30 in an interlocking relationship which secures the inner cylindrical component 30 in a fixed, locked position within the outer cylindrical component 32. The inner cylindrical component 30 is movable between the fixed, locked position and a rotatable, unlocked position, relative to the outer cylindrical component 32, and is actuated by the pivotable paddle 28.

In the preferred embodiment, the means for selectively locking and unlocking the locking mechanism and actuating the inner cylindrical component 30 include a pair of actuator trunnions or pins 44 in communication with the paddle 28, which extend outward from opposite sides of the inner cylindrical component 30 near the top 38. As shown in Fig. 3, the paddle 28 has an outer end 46, an inner end 48, and a body 50. The inner end 48 of the paddle is connected to and extends from an inner bushing yoke or cylindrical ring 54 which includes a pair of trunnion or pin holes 56. When assembled, the pins 44 extend through the holes 56 of the ring 54 to connect

the inner cylindrical component 30 and the paddte 28 so that when downward pressure is applied to the paddle 28 and the ring 54 is tilted in an upward direction, the pins 44 are likewise raised to move the inner cylindrical component 30 from its normally engaged, locked position, within the outer cylindrical component 32, to an unlocked, rotatable position.

As seen in Fig. 3, the preferred embodiment includes a hollow cover or upper locking clip 58 which has a top section 60, a middle section 62 and a bottom section 64 having a bottom rim 66. The top section 60 includes a top opening 68 for receiving the front leg tube 14, and the bottom section 64 includes a bottom opening 70 for receiving the inner cylindrical component 30 within the upper locking clip 58. The clip 58 includes a pair of slots 72 positioned across from one another on opposite sides of the clip 58 for receiving the actuator pins 44 of the cylindrical component 30. Each slot 72 extends from the middle section 62 through the bottom section 64 of the clip and has a closed, top end 74 and an open, bottom end 76 extending through the bottom opening 70 of the clip 58. The open, bottom end 76 allows the pin 44 to be received into the slot 72 and the top, closed end 74 provides a stop for the pin 44 for limiting the vertical movement of the inner cylindrical component 30. The clip 58 further includes a platform 78 extending from the bottom section 64 of the clip 58 and having opposite sides 80. The platform 78 includes a pair of pivot pins 82 mounted to and extending outward from the sides 80 of the platform 78.

When assembled on the walker, the upper locking clip 58 is rotatably secured to each front leg tube 14 in a vertically fixed position with the bottom rim 66 adjacent to the top edge of the outer cylindrical component 32. The clip 58 includes a biasing means, such as an internal spring button 84 and a rivet hole 86 for securing to the front leg tube 14. As shown in Fig. 4, the inner cylindrical component 30, the outer cylindrical component 32, the upper locking clip 58 and the ring 54 of the paddle 28 are adapted to lit together. Ring 54 is positioned over the clip 58 and rests on the bottom rim 66 when the loclcing mechanism is in the locked position with the actuator pins 44 extending outward through the actuator holes 56 of the ring 54. Paddle 28 may pivot when downward pressure is applied to the paddle 28. Such downward pressure applied to the outer end 46 of the paddle 28 causes the paddle 28 to pivot on pins 82 that are received in holes 52 in paddle 28, so that the ring 54 is lifted and actuator pins 44 are moved upward through the slots 72 of the clip 58. This disengages the upper portion 36 of the inner cylindrical component 30 from the outer cylindrical component 32, moving it to a rotatable, unlocked

position. While continuing to apply downward pressure, the user pulls each paddle 28 and or the side 12 in an inward direction which rotates the clip 58 and the raised unlocked, cylindrical component 30, permitting the inverted U-shaped sides 12 to a closed, storage position.

The locking mechanism 26 includes an integral means for selectively maintaining the inner cylindrical component 30 in the unlocked position and holding the inverted U-shaped sides 12 of the walker 10 in the folded, storage position. A spring 110 forces the inner cylindrical component 30 into locking engagement with the outer cylindrical component 32. Thus, the walker 10 will normally remain in the open, locked position until pressure is applied to the paddle 28 to move the inner cylindrical component 30 from locking engagement to the unlocked, rotatable position. The integral means includes a ledge 94 in the outer cylindrical component 32 and a uniquely configured vertically projecting tooth 96 on the inner cylindrical component 30.

The ledge 94 is defined by a short vertical projection or partial spline between the channels 42 which does not extend to the top edge of the tube collar 24. As shown in Fig. 3, the ledge 94 has a top side 98. The vertically deep projecting tooth 96 includes a shoulder 100 having a bottom edge 102 which extend from the top end 38 of the inner cylindrical component 30 to the same length as the vertically projecting teeth 40 through the upper portion 36, and a long portion 104 adjacent to the shoulder 100 which extends from the top end 38 through the lower portion 34 of the inner cylindrical component 30. In the locked position, the shoulder 100 rests on the ledge 94 while the long portion 104 is positioned within the channel 42. As pressure is applied to the paddle 28 to raise the inner cylindrical component 30, the vertical teeth 40 are disengaged from the channels 42, and the long portion 104 is raised to a height slightly above the ledge 94, while remaining in the channel 42. When pivoted inward, the long portion 104 of the tooth 96 contacts the top side 98 of the ledge 94, which forces the cylindrical component 30 to remain in the unlocked position with the sides 12 in the closed, folded position. To open the walker, the sides 12 are pulled outward causing the inner cylindrical component 30 to pivot so that the portion 104 loses contact with the ledge 94 and the vertical teeth 40 fall into their interlocking position within the outer cylindrical component 32 to secure the walker in the open position for use.

The integral means also includes a safety feature by providing a stop for presenting a pressed paddle and the side 12 with which it is associated from inadvertently pivoting outward, which would cause the side to swing out away from the user. As pressure is applied to the

paddle 28, the upper portion 36 of the inner cylindrical component 30 is removed completely from the outer cylindrical component 32 to raise the vertical teeth 40 out of the channels 42.

Although the raised inner cylindrical component may be freely rotated in an inward direction, the long portion 104 of the tooth 96 contacts an internal spline 41 of the channel 42 and prevents the inner cylindrical component 30 from rotating in an outward direction away from the user. Thus, the stop provides a safety feature which permits the unlocked inner cylindrical component 30 to pivot only inward direction ensuring that the unlocked sides 12 of the walker are folded inward against the front center brace 18.

In the preferred embodiment, the front center brace 18 of the foldable walker 10 is molded from a single piece of durable, lightweight plastic, such as polypropylene with twenty percent (20%) talc. As can be seen in Figs. 1-3, the molded front center brace 18 extends across the front of the walker 10 and includes the tube collars 24 for securing the brace 18 to the front leg tube 14 of each side 12. In the preferred embodiment, the outer cylindrical component 32 is integral with the top portion of the tube collar 24 and receives the inner cylindrical component 30 to provide a locking means for selectively locking and unlocking the walker. Because the front center brace 18 is molded from a single piece and includes one of the locking elements comprising the locking mechanism, the foldable walker 10 of the present invention requires a minimal number of components and is inexpensive to manufacture and simple to assemble while providing a sturdy walker with increased strength. Each side brace 20 may be molded in a single piece of durable, lightweight thirty-three percent (33%) glass filled nylon. Each molded side brace 20 is adapted to be secured to and extends between the front and rear leg tubes 14,16 of the walker 10. Like the molded front center brace 18, the molded side braces 20 are inexpensively manufactured and easily assembled on the walker 10. The other plastic components may also be thirty-three percent (33%) glass filled nylon.

The foldable walker and locking mechanism of the present invention is not confined to the embodiments described herein but includes variations and modifications within the scope and spirit of the foregoing description, the accompanying drawings and the following claims.




 
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