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Foldable pawl and ratchet assemblyFoldable pawl and ratchet assembly description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070040419, Foldable pawl and ratchet assembly. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates in general to furniture member operating mechanisms and more specifically to a device and method for operating a furniture leg rest assembly. BACKGROUND OF THE INVENTION [0002] Conventionally, reclining articles of furniture (i.e., chairs, sofas, loveseats, and the like) require a mechanism to bias a leg rest assembly in the extended and stowed positions. Known mechanisms commonly include a large number of moving parts that tends to increase the manufacturing time and costs associated with the furniture. [0003] Most rocking chairs typically include an upholstered chair frame supported from a stationary base assembly in a manner permitting the chair frame to "rock" freely with respect to the base assembly. In order to provide enhanced comfort and convenience, many rocking chairs also include a "reclinable" seat assembly and/or an "extensible" leg rest assembly. For example, combination platform rocking/reclining chairs, as disclosed in Applicant's U.S. Pat. Nos. 3,096,121 and 4,179,157, permit reclining movement of the seat assembly and actuation of the leg rest assembly independently of the conventional "rocking" action. The leg rest assembly is operably coupled to a drive mechanism to permit the seat occupant to selectively move the leg rest assembly between its normally retracted (i.e., "stowed") and elevated (i.e., "extended") positions. The drive mechanism is manually-operated and includes a handle which, when rotated by the seat occupant, causes concurrent rotation of a drive rod for extending or retracting the leg rest assembly. [0004] As an additional comfort feature, a latching mechanism may also be provided for releasably retaining the chair frame in one or more rearwardly rocked or "tilted" positions on the base assembly following extension of the leg rest assembly towards its extended position. In this manner, normal "rocking" action of the rocking chair is inhibited until the leg rest assembly is returned to its normally "stowed" position. Applicant's above-mentioned U.S. patents each disclose the use of a "one-way" pawl and ratchet type latching mechanism having a pawl member supported for pivotable movement from the base assembly and a toothed ratchet sector fixed to the chair frame. An elongated U-shaped spring link is used to couple the pawl member to a drive link fixed to the drive rod. [0005] Movement of the pawl member between positions of engagement and disengagement with the toothed ratchet sector is caused in response to movement of the leg rest assembly between its extended and retracted positions, respectively. More particularly, when the handle is slightly rotated for partially extending the leg rest assembly, concurrent rotation of the drive rod and the drive link causes the spring link to forcibly pivot the pawl member toward the toothed ratchet sector until the locking tip of the pawl member is positioned in locked engagement with the teeth of the ratchet sector. Thereafter, continued rotation of the drive rod and drive link for completely extending the leg rest assembly causes "elastic" flexure of the elongated spring link for applying a compressive force on the pawl member. [0006] However, the magnitude of the compressive force exerted by flexure of the spring link can vary since the displacement between the drive rod and sequential ratchet points on the ratchet sector vary in response to rearward tilting movement of the chair frame. Therefore, the flexure of the elongated spring link must be sufficient to ensure that the compressive force exerted on the pawl member is sufficient to maintain locked engagement between the pawl member and the teeth of the ratchet sector throughout the entire range of rearward "tilting" movement of the chair frame. The common one-piece construction of the pawl arm and locking tip may not provide the optimum angle for engagement with the teeth of the ratchet sector. An improved pawl/ratchet assembly is therefore desirable to improve engagement between the pawl and ratchet assembly. [0007] Known leg rest mechanisms also provide multiple functional positions, which can be reached using a detent mechanism, which temporarily holds the leg rest at each successive position. As the furniture member rocks backward when the leg rest is moved between the successive positions, a noticeable ratcheting or clicking noise occurs as the pawl engages successive teeth of the ratchet. This noise results at least in part because common pawl members and ratchet sectors are both created of metal material which transmit contact noise. An improved pawl/ratchet assembly is therefore desirable to reduce this operational noise. SUMMARY OF THE INVENTION [0008] According to one preferred embodiment for a foldable pawl and ratchet assembly of the present invention, a ratchet device for a furniture member having a plurality of structural elements is operable to temporarily retain the furniture member in each of a plurality of rotated engaged positions. The ratchet device includes a pawl assembly having a pawl link rotatably connectable to a first one of the structural elements of the furniture member; a pawl lever rotatably connectable to the pawl link; and a biasing element operable to bias the pawl lever toward a contact position with the pawl link. A ratchet assembly includes a ratchet body having a plurality of engagement teeth. The ratchet assembly is fixed to a second one of the structural elements and located to position the engagement teeth in a rotational path of the pawl lever upon rotation of the pawl link. [0009] In another aspect of the invention, a ratchet device for a rocking furniture member has a plurality of structural elements. The ratchet device temporarily retains the furniture member in multiple engaged positions and includes: a pawl assembly having a pawl link rotatably connected to a first structural element; a plastic pawl lever rotatably connected to the pawl link; a first biasing element positioned between the pawl link and the pawl lever which biases the pawl lever toward a contact position with the pawl link; and a U-shaped bracket rotatably coupled to the pawl link and fixed to the first structural element. A ratchet having engagement teeth is fixed to a second structural element and located with the engagement teeth in a rotational path of the pawl lever. A second biasing element connected between the pawl link and the U-shaped bracket biases the pawl lever to engage the ratchet teeth. [0010] According to another aspect of the invention, a furniture member leg rest mechanism is connectable to both a furniture member structure and a seat frame. The leg rest mechanism includes a drive mechanism having a drive rod for rotational movement in a first and second direction, an actuator permits a seat occupant to selectively actuate the drive mechanism, a ratchet providing a plurality of ratchet teeth, and a pawl assembly having two independently rotatable members. [0011] According to still another aspect of the invention, a method for creating a pawl and ratchet assembly operable to position a furniture member in each of a plurality of engagement positions is provided. [0012] A foldable pawl and ratchet assembly of the present invention provides several advantages. By rotatably coupling a pawl lever to a pawl link, the pawl lever can more easily disengage from an engaged position between teeth of a ratchet, to allow continued backward rotation of a furniture member. The use of a polymeric material for the pawl lever provides a quieter operation as the pawl lever rotates past the teeth both between engaged positions and when pawl lever is released. The polymeric material also reduces the sliding contact friction between the pawl lever and teeth. A biasing element continuously biases pawl lever toward a contact position with pawl link which promotes engagement of a ratchet engaging end of pawl lever with teeth to prevent forward or return motion of the furniture member until the operator manually disengages the leg rest operating mechanism and pawl assembly together. [0013] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating some aspects of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0014] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0015] FIG. 1 is a front perspective view of a reclining chair having a foldable pawl and ratchet assembly of the present invention; [0016] FIG. 2 is an exploded perspective view of a chair with upholstery, biasing elements and other parts removed from the pre-assembled components for illustrating the adjustable spring toggle assembly for an actuation mechanism; [0017] FIG. 3 is a plan view of the leg rest mechanism in accordance with a preferred embodiment of the present invention; [0018] FIG. 4 is a cross sectional side elevational view taken at section 4-4 of FIG. 3; [0019] FIG. 5 is a front perspective exploded assembly view of the folding pawl assembly of one aspect of the present invention; [0020] FIG. 6 is a front elevational view of the pawl lever of FIG. 5; Continue reading about Foldable pawl and ratchet assembly... Full patent description for Foldable pawl and ratchet assembly Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Foldable pawl and ratchet assembly patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Foldable pawl and ratchet assembly or other areas of interest. ### Previous Patent Application: Electrical device cooling structure in vehicle Next Patent Application: Foldable structure of highchair Industry Class: Chairs and seats ### FreshPatents.com Support Thank you for viewing the Foldable pawl and ratchet assembly patent info. 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