BACKGROUND OF THE INVENTION1. Field of the Intention
The present invention relates to a chair lift. More specifically, the present invention relates to a chair which allows a user to push downwardly on arm rests to cause, with the help of ropes and pulleys, a rear portion of said seat to be efficiently lifted upwardly thus helping the user to stand up and get out of the chair.
2. Description of the Prior Art
A variety of lift chair devices have been proposed over the years. A number of existing patents teach the use of an electric screw drive or the like to lift all or a large portion of a chair to assist a user to stand up. Examples of such devices include: Ambrose, Jr. et al., U.S. Pat. No. 6,106,062; Lin, U.S. Pat. No. 5,312,153; Gaffney, U.S. Pat. No. 4,083,599; Mohn et al., U.S. Pat. No. 7,090,297; Gaffney, U.S. Pat. No. 4,909,569; Rudes et al., U.S. Pat. No. 5,294,179; and Kemmerer et al., U.S. Pat. No. 5,931,532.
Marcoux et al., U.S. Pat. No. 6,213,554 provides a lift chair utilizing a piston 96 to tip a chair forward. Kao et al., U.S. Pat. No. 7,021,713 utilizes a telescopic lifter 40 to lift a movable seat portion 22 of a chair.
Bressler et al., U.S. Pat. No. 7,000,988 discloses a lift chair which utilizes biasing means preferably in the form of gas springs 80 to lift a chair (see FIG. 2). The gas springs can be placed in various locations.
Crisp, U.S. Pat. No. 5,082,327 discloses a lift apparatus for use with a chair which provides a number of torsion springs 46 which tend to spread the upper and lower frame members apart from each other. The number of springs and their spring rates may be varied to provide the proper lift for a given weight range of intended users.
Geraci, U.S. Pat. No. 4,979,726 provides a chair having a lift apparatus which uses a spring operated lever assembly 26. Geraci, U.S. Pat. No. 4,929,022 provides a lift chair wherein the user steps on a foot rest, pulls rearwardly on hand gripped levers and springs assist the user in standing up (see FIG. 2).
Bathrick et al., U.S. Pat. No. 5,094,508 discloses an elevator chair which includes a vertically telescopic back frame which is raised and lowered by a motor driven screw and tube assembly. As shown in FIG. 1 rear legs 30 and 31 are telescopically disposed in rear square frame tubes 18 and 19.
Poncy et al., U.S. Pat. No. 4,690,457 discloses a chair with a lift assist mechanism which utilizes a pneumatic cylinder 34 to lift a seat frame 11 and cushion 12 by manipulating a control lever 50.
Farran et al., U.S. Pat. No. 4,913,423 discloses a chair which includes a cable 74 and plural pulleys 71 and 72 (FIG. 3) along the sides of the chair which are used for exercise purposes.
Other devices of general interest include Olcheski, U.S. Pat. No. 7,255,397 (infrared sensing chair lift); Johnson, U.S. Pat. No. 4,266,468 (wall clearing recliner); and Sicher, U.S. Pat. No. 6,173,986 (rowing arms driven wheel chair).
There remains a need for a lift chair which is inexpensive to produce and which does not require external power, lift cylinders, springs, screw jacks or other biasing means. There also remains a need for a lift chair which efficiently utilizes the natural force of a user pushing downwardly on the arms of a chair to provide a vertical lift on the seat of a chair.
SUMMARY OF THE INVENTIONMany senior citizens, older adults and persons with disabilities have difficulty standing up from a seated position. It is common for such individuals to use table tops to push their bodies upward, or to push downwardly on their legs as they raise their bodies from a seated position. After considering this problem, careful observation has revealed that in almost every case when such individuals tried to get up they would push down on their legs, the sides or arms of the chair or on the surface of the table. These observations can be summarized that people pushed down to stand up.
Studies have shown that when going from being seated to a standing position, people start the process by utilizing their hip muscles followed by the use of the thigh and knee muscles as they raise their bodies. When standing up, nearly all of the stress is put on the legs. Unfortunately, the elderly struggle because the specific muscles used for this process tend to get weaker as they age. Most individuals tend to use muscles less and less over time as we grow older. This causes muscles to atrophy (decrease in size) over time if they are not used. In addition, arthritis is the number one major chronic health condition for elderly Americans. These are the primary reasons why so many seniors have trouble standing up from chairs. Because elderly persons have trouble lowering and raising their bodies into and out of chairs, many products are on the market but they tend to be expensive, heavy and bulky. Because many elderly persons have modest income levels and many others are impoverished, there is a clear need for an inexpensive solution to this simple daily task.
Some of the positive attributes of a chair which are preferably incorporated into the present invention include a high back (to take weight off the lower spine); high, wide and slightly sloped armrests which allow the user to push themselves up and which ease pressure on the arms; comfort; and a sloping waterfall front seat edge (to reduce pressure on the user's legs and to ensure better circulation). The chair should also be lightweight, affordable and convenient.
In its simplest form the present invention provides a lift chair comprising:
a) a frame having a plurality of legs and a back rest portion;
b) a seat having a front portion pivotally attached to said frame and having a rear portion, said seat movable from a first generally horizontal sitting position to a second angled lift position wherein said rear portion of said seat is lifted upwardly;
c) arm rests members movably attached to opposite sides of said frame, each arm rest member having a generally horizontal arm rest portion and a vertical activating rod member attached to said arm rest portion, said arm rests movable from a first upper vertical position to a second lower vertical position; and
d) rope and pulley means including a pulley attached to a lower end of each activating rod and plural pulleys attached to said frame with a rope attached to said rear portion of said seat, said rope extended around said pulleys whereby pushing downwardly on said arm rests causes said arm rests to move from said a first upper vertical position to said second lower vertical position which causes said rear portion of said seat to move from a first generally horizontal sitting position to said second angled lift position.
Preferably, each of the legs have a vertical arm rest chamber therein and each arm rest member has at least one attachment post whereby each arm rest post is telescopically received in an arm rest chamber. Preferably, a pair of front legs and a pair of rear legs are provided. Preferably, said plural pulleys attached to said frame include, on each opposite side of said frame, a pulley on a front leg, a pulley on a rear leg and a pair of pulleys on said back rest portion.
Preferably, said rear portion of said seat further comprises a pair of rear extension members and a rear seat pulley attachment rod extending between said rear extension members. Preferably, said rear extension portion members extend through and slide upwardly and downwardly in slots provided in said back rest portion.
Preferably, said pulley means includes at least five pulleys but may in one embodiment include at least six pulleys. It will be obvious to those of ordinary skill in the art that the choice of more pulleys provides a greater mechanical advantage but requires a further travel of the arm rest to achieve the same degree of lifting of the rear seat portion. Preferably, a rope and pulley means is provided on each side of said frame and each rope and pulley means is enclosed under a cover. As used in this application, the term “rope” is to be defined broadly and includes any type or form of rope, cable, wire, cord or string or any other flexible elongated member which may be effectively used with pulleys.
BRIEF DESCRIPTION OF THE FIGURESFIG. 1 is a perspective view of the lift chair of the present invention with the arm rests in a second lower vertical position and the seat in a second angled lift position and also showing, in chain line, the arm rests in a first upper vertical position and the seat in a first horizontal sitting position.
FIG. 2 is a side elevation view showing an arm rest in the second down position.
FIGS. 3A,3B,3C and3D show various arrangements of pulleys and show the mechanical advantage of adding additional pulleys.
FIG. 4 is a side elevation view showing the presently preferred arrangement of pulleys and the direction of movement of the rope at various locations when a downward force is placed on an arm rest.
FIG. 5A is a schematic view of the preferred pulley arrangement on a chair.
FIG. 5B is a schematic view of an alternative pulley arrangement on a chair.
FIG. 5C is a schematic view of yet another pulley arrangement on a chair.
FIGS. 6A,6B,6C,6D and6E are schematic views of various pulley arrangements with five pulleys arranged in the same basic layout but with different size pulleys and with different configurations of rope interconnections.
FIG. 8 is a perspective view of a lift chair according to the present invention (pulleys not shown) in a normal sitting position with the arm rests in a first upper vertical position and the seat in a first horizontal sitting position.
FIG. 8 is a perspective view of a lift chair according to the present invention (pulleys not shown) in a raised assist position with the arm rests pushed down to a second lower vertical position and the rear of the seat in a second angled lift position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSReferring toFIG. 1 the lift chair of the present invention has aframe100 which includeslegs110,120,130 and140 and aback rest portion150. Aseat200 has afront portion202 which is pivotally attached to said frame at205 (FIG. 8) and has arear portion204. Theseat200 movable from a first generally horizontal sitting position220 (FIG. 7) to a second angled lift position230 (FIG. 8) wherein therear portion204 of saidseat200 is lifted upwardly.Arm rest members300 are movably attached to opposite sides of saidframe100. Eacharm rest member300 has a generally horizontalarm rest portion302 and a vertical activatingrod member304 attached to saidarm rest portion302. The arm rests300 are movable from a first upper vertical position330 (FIG. 7) to a second lower vertical position320 (FIG. 8). A rope andpulley400 means including apulley410 attached to a lower end of each activatingrod304 andplural pulleys420,430,440 and450 attached to saidframe100 with arope500 attached to saidrear portion210 of saidseat200. Therope500 extends around thepulleys410,420,430,440 and450 whereby pushing downwardly on said arm rests300 causes said arm rests to move from said a first uppervertical position330 to said second lowervertical position320 which causes saidrear portion204 of saidseat200 to move from a first generally horizontal sittingposition220 to said secondangled lift position230.
Thelegs110,120,130 and140 each have a vertical arm rest chamber orchannel124 therein and eacharm rest member300 has at least one and preferably twoattachment posts350 therein whereby eacharm rest post350 is telescopically received in anarm rest chamber124. This allows thearm rest300 to slide upwardly and downwardly relative the frame (in the legs) in a smooth guided manner. The vertical arm rest chambers are drilled or otherwise provided into the upper ends112,122,132 and142 oflegs110,120,130 and140, respectively. The chair rests on the floor or ground in lower ends114,124,134 and144 of said legs.
The legs include a pair offront legs110 and120 and a pair orrear legs130 and140. Plural pulleys are attached to theframe100 and preferably include, on each opposite side of said frame, apulley420 on afront leg120, apulley430 on arear leg140 and a pair ofpulleys440 and450 on said backrest portion150.
Therear portion204 of theseat200 further comprises a pair ofrear extension members206 and208 and a rear seatpulley attachment rod210 extending between saidrear extension arms206 and208. As shown, therear extension members206 and208 extend through and slide upwardly and downwardly inslots174 and172, respectively, provided in said backrest portion150.
The rope and pulley means400 preferably includes at least five pulleys, such aspulleys410,420,430,440 and450. In one embodiment the pulley means400 can include at least six pulleys, such aspulleys410,420,430,452,460 and470 (FIG. 5B) or such aspulleys410,420,430,440,450, and455 (FIG. 5C). To prevent possible injury or having a user getting caught in the rope and pulley means400 any suitable cover or guide (not shown) is preferably placed over the rope and pulley means on each side of theframe100.
InFIG. 1, the lift chair of the present invention is shown with the arm rests300 in a second lowervertical position320 and the seat in a secondangled lift position230.FIG. 1 also shows however, in chain line, the arm rests300 in a first uppervertical position330 and the seat in a first horizontal sittingposition220.
Theback rest portion150 of theframe100 hasframe members151,152 and154 on one side and members161 (not shown)162 and164 on an opposite side. Theback rest portion150 has a largecentral back portion170 which is located between thegrooves172 and174 in which therear seat extensions208 and206 extend. Some of these back rest portion members are also shown inFIG. 2.
As is well known in the art,FIGS. 3A,3B,3C and3D show various arrangements of pulleys and show the mechanical advantage of adding additional pulleys. For example with only one pulley (FIG. 3B) no mechanical advantage is obtained but only a change in direction in the force applied.FIG. 3C shows the use of two pulleys to lift a 100 pound weight with only 50 pounds of force required. Similarly,FIG. 3D shows the use of three pulleys to lift a 100 pound weight with only 25 pounds of force required.
FIG. 4 shows the direction therope500 is moving at various locations as thearm rest300 is pressed downwardly in the direction ofarrow600. Such action forcedvertical activation rod304 downwardly thus casing therope500 to move downwardly atarrows602,604,606,608 and610. This in turn causes therope500 to move upwardly atarrow612 lifting therear portion204,210 of seat in the manner previously described.
FIGS. 5A,5B,6A,6B,6C,6D and6E show various pulley and rope configurations and variations which will be well understood by those of skill in the art.
FIG. 7 showsseat200 in its first generally horizontal sittingposition220. The arm rests300 are shown in a first uppervertical position330.FIG. 8 also shows more clearly that eacharm rest post350 is telescopically received in anarm rest chamber124. It is to be understood that various techniques and methods can be utilized to reduce friction as the arm rest posts350 slide into and out of thechambers124 in the legs. For example, drawer slides could be utilized with elongated slide tracks being placed into eachchamber124 with rollers (which travel smoothly in said slide tracks) mounted on said arm rest posts. Various other types of drawer slides or ball bearing slides can be used to reduce friction so that more of the downward force on the arm rests300 results as a lifting force.
FIG. 8 shows theseat200 in a secondangled lift position230 wherein therear portion204 of saidseat200 is lifted upwardly. The arm rests300 are in a second lowervertical position320. InFIG. 8 the arm rest posts350 are completely received within thechamber124 in thelegs110,120,130 and140 offrame100.
In operation, the present invention is amazingly simple because it is designed to utilize the normal motion which a user typically engages in to get out of a chair. The user simple pushes down on the arm rests300 and the rope and pulley means400 provides an enormous mechanical advantage and allows the user to far more easily reach a standing position. The various components of the present invention can be fabricated from any suitable materials such a wood, plastic or metal.
It is to be understood that while certain forms of the present invention have been illustrated and described herein, the present invention is not to be limited to the specific forms or arrangements of parts described and shown.