Patent Application
20100109410
The present invention relates generally to chairs for supporting a patient during examinations and treatments, and more particularly to a chair for use in a dental operatory.
Conventional dental operatories generally include an articulating dental chair for supporting a patient in a variety of positions to facilitate the performance of dental procedures and operations. For example, dental chairs are generally adapted to be raised and lowered relative to a floor surface, and to be moved between a first orientation where a back cushion is inclined relative to a seat cushion to support the patient in a seated position, and a second orientation where the seat cushion is reclined to support the patient in a generally supine position.
In some dental chairs, the seat cushion is supported by a chair frame and the back cushion is coupled to an upright support that moves relative to the chair frame along a predetermined path or track (i.e., the support does more than merely pivot with respect to the chair frame). This upright support is sometimes referred to as a “carriage.” A lower portion of the carriage is typically received between sidewalls of the chair frame. The carriage slides relative to the chair frame between the sidewalls and along the predetermined path to move the dental chair between the first and second orientations mentioned above.
One of the challenges associated with this type of dental chair relates to coupling the carriage to the chair frame. The carriage should be coupled (i.e., connected) to the chair frame in a manner that allows movement between the first and second orientations without a significant amount of “slop” or “play” between the components. In other words, the carriage should remain relative stable relative to the chair frame as the seatback is moved through its range of motion (both from the first orientation to the second orientation and vice-versa).
To address this concern, manufacturers may design the carriage, chair frame, and various other associated components to have relatively tight tolerances. For example, the lower portion of the carriage may be received between the sidewalls of the chair frame with little clearance. However, designing components with relatively tight tolerances increases the potential for poor fits or mismatches between the components.
Therefore, a dental chair that provides an improved fit between a carriage and a chair frame without requiring relatively small tolerances is highly desirable.
A chair for supporting a patient during examinations or treatments is described below. The chair is particularly suited for use in a dental operatory, although the invention is not so limited.
In one embodiment, the chair generally comprises a base, a chair frame supported by the base, and a seatback support (or “carriage”) coupled to the chair frame. The seatback support is slidably movable relative to the chair frame. To provide a “close fit” or proper connection between components, a locking assembly is configured to apply a clamping force between the seatback support and the chair frame.
In another embodiment, the chair frame includes first and second sidewalls. The seatback support has a lower portion received between the first and second sidewalls, and the locking assembly is associated with one of the first or second sidewalls. The locking assembly includes an engagement member coupled to the lower portion of the seatback support, a clamp plate facing an outer surface of the associated first or second sidewall, and a fastener having a head portion retained against the clamp plate and a shaft portion extending through the clamp plate and first or second sidewall. The shaft portion has threads for engaging the engagement member.
In yet another aspect or embodiment, the chair further includes a drive mechanism supported by the chair frame and coupled to the seatback support. The drive mechanism is configured to slidably move the seatback support relative to the chair frame. In some embodiments, the drive mechanism is a one-way hydraulic cylinder configured to move the seatback support from a reclined position to an upright position relative to the chair frame.
Chair 2 generally comprises base 4, a lift arm 6 extending upwardly from base 4, and a seat assembly 8 supported by lift arm 6. Lift arm 6 raises and lowers seat assembly 6 relative to base 4. A seatback support 10 (referred to as a “carriage”) extends generally upwardly from seat assembly 8 for supporting a seatback frame 12 (
In one embodiment, seat assembly 8 includes a chair frame 20 mounted to lift arm 6 by a seat mount assembly 21, a casing assembly 22 mounted to chair frame 20, and a seat cushion 24 positioned over chair frame 20 and casing assembly 22.
The drive mechanism 26 shown in
When the force of drive mechanism 26 is released, one or more return springs 76 pull support shaft 36 and lower portion 34 of seatback support 10 toward a forward end 78 of each arcuate track 40. Again, the first, second, and third guide shafts 46, 54, 56 cooperate with arcuate tracks 40 to translate the applied forces into arcuate motion. Those skilled in the art will appreciate that this arrangement is merely one example of how seatback support 10 may slide relative to chair frame 20. Indeed, chair 2 may alternatively include a two-way hydraulic cylinder, a mechanical linear actuator, or any other type of drive mechanism 26 for moving seatback support 10 relative to chair frame 20.
Now referring to
In one embodiment, clamp plate 84 further includes a first clearance hole 120 substantially aligned with the axis of first guide shaft 46 and a second clearance hole 122 substantially aligned with the axis of second and third guide shafts 54, 56. The end portions 48, 58 of the first and second guide shafts 46, 54 extend through the respective clearance holes 120,122 when locking assembly 80 is installed. Various spacing components may be provided over first and second guide shafts 46, 54 between first sidewall 28 and clamp plate 84. For example, as shown in
To assemble chair 2, seatback support 10 is positioned between the first and second sidewalls 28, 30 of chair frame 20 and guide shafts 46, 54, 56 are positioned with their end portions 48, 58, 60 in the associated arcuate track 40. At this point, there may be a small amount of “play” between seatback support 10 and chair frame 20. To provide a more stable arrangement, clamp plate 84 is positioned with clearance holes 120, 122 over the respective end portions 48, 58 of first and second guide shafts 46, 54. Shaft portion 110 of fastener 88 is inserted through a central hole 136 in clamp plate 84 and into bore 90 of engagement shaft 82. Fastener 88 is then tightened (i.e., rotated) to engage shaft portion 110 with the threads of bore 90 thereby pulling seatback support 10 toward first sidewall 28. Because head portion 112 of fastener 88 is retained against the clamp plate 84, locking assembly 80 applies a clamping force between seatback support 10 and first sidewall 28. This clamping force maintains a relatively stable connection between seatback support 10 and chair frame 20 so as to eliminate “slop” during the movement of seatback support 10 between the generally upright position and the generally reclined position.
As can be appreciated, locking assembly 80 reduces or eliminates the need to design the seatback support 10 and chair frame 20 with relatively tight tolerances. There may be a fair amount of play when the components are first assembled, but the play is eliminated when locking assembly 80 is tightened. This may be a one-time step performed when chair 2 is first assembled. Casing assembly 22 (
While the invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, engagement shaft 82 may be replaced with any suitable structural component coupled to lower portion 34 of seatback support 10 and configured engage fastener 88. Indeed, it will be appreciated that other components of locking assembly 80 described with specificity above may be replaced with other structural elements capable of performing similar functions. Additionally, although chair 2 only includes a single locking assembly 80, an additional locking assembly (not shown) may be associated with second sidewall 30 if desired.
The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.
