Reclining chair

A reclining chair that avoids skin shear. The reclining chair has a seat, a backrest, and a backrest surface. The backrest is pivotably attached to the seat. The backrest surface is slidably mounted with respect to the backrest. Pivoting of the backrest with respect to the seat causes the backrest surface to slide with respect to the backrest. Sliding of the backrest surface with respect to the backrest maintains the backrest surface at a constant position relative to a back of a person sitting on the reclining chair.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a reclining chair that does not 
cause skin shear. More particularly, the present invention relates to a 
reclining chair in which a backrest cushion slides with respect to a 
backrest as the backrest is pivoted with respect to a seat. 
There are many situations where it is desirable to have a chair in which 
the backrest of the chair reclines with respect to a seat. In prior art 
reclining chairs, a seat cushion is fixedly mounted to the seat and a 
backrest cushion is fixedly mounted to the backrest. Pivoting of the 
backrest with respect to the seat increases a distance between the 
backrest cushion and the seat cushion. 
When a person is sitting on the reclining chair, increasing the distance 
between the backrest cushion and the seat cushion changes a position of 
the backrest cushion with respect to the person's back. Changing the 
position of the backrest cushion with respect to the person's back 
produces shear forces on the portions of the person's back that are in 
contact with the backrest cushion. 
When the reclining chair is used by a person having delicate skin, such as 
an elderly person, the skin is unable to accommodate the amount of 
displacement caused by the movement of the backrest cushion. Depending on 
the condition of the person's skin, the movement of the backrest cushion 
may cause skin abrasions or even rupture. 
Regardless of the extent of the physical effects, skin shear is undesirable 
and should be avoided. Prior to the present invention, no reclining chair 
adequately compensated for skin shear. 
Several patents disclose pivotably mounting a backrest to a seat to form a 
reclining chair. For example, Zapf et al. U.S. Pat. Nos. 5,367,336 and 
4,452,486 disclose structures in which sliding of the seat away from the 
backrest causes the backrest to pivot with respect to the seat and thereby 
move the chair into a reclined position. 
Smith U.S. Pat. No. 1,007,985 describes a chair having a backrest that is 
attached to a frame using belts and pulleys. The mounting of the backrest 
allows the backrest to be manually adjusted in a vertical direction. 
Neve De Mevergnies U.S. Pat. No. 4,676,550 discloses an automobile seat 
having a backrest cushion that is mounted using a belt and pully system so 
that the backrest cushion can oscillate up and down in response to the 
automobile hitting bumps on a roadway. Neve De Mevergnies indicates that 
such a configuration minimizes stress placed on the back of a person 
sitting in the chair. 
SUMMARY OF THE INVENTION 
The present invention includes a reclining chair having a seat and a 
backrest, which is pivotably mounted to the seat. The reclining chair also 
has a backrest cushion that is slidably mounted on the backrest. Pivoting 
of the backrest with respect to the seat causes the backrest cushion to 
slide with respect to the backrest. Sliding of the backrest cushion with 
respect to the backrest maintains the backrest cushion in a constant 
position relative to a back of a person sitting on the reclining chair.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention includes a reclining chair, as most clearly 
illustrated at 10 in FIG. 1. The reclining chair 10 has a seat 12 and a 
backrest 14. The backrest 14 is pivotably connected to the seat 12 so that 
backrest is pivotable about an axis 16, as illustrated in FIGS. 2 and 3. 
Pivotably mounting the backrest 14 to the seat 12 allows the reclining 
chair 10 to move from an upright position, illustrated in FIG. 2, to a 
reclined position, illustrated in FIG. 3. 
The backrest 14 includes a frame 20 that extends around the outside of the 
backrest 14, as depicted in FIG. 1. The frame 20 is preferably fabricated 
from a rigid metallic material, such as aluminum or steel. The frame 20 is 
preferably constructed with a top member 22, a pair of side members 24, 
and a bottom member 26. The frame 20 also preferably includes a 
reinforcing bar 28 that is mounted to extend between the side members 24 
approximately intermediate between the top member 22 and the bottom member 
26. In addition to providing additional strength to the frame 20, the 
reinforcing bar 28 provides a handle that may be used for moving the 
reclining chair 10. 
A backrest support surface 32 is formed on the backrest 14 using a 
plurality of straps 30. The straps 30 are attached to the frame 20 in a 
horizontal relationship so that the straps 30 extend between the side 
members 24. The straps 30 are preferably formed from a plastic material 
that stretches to a small degree when a force is applied but returns to 
the original shape when the force is removed. 
The seat 12 preferably has a structure that is similar to the backrest 14. 
In particular, the seat 12 preferably includes a frame 40, which is formed 
from a metallic material, such as aluminum or steel. The seat 12 includes 
a seat support surface 46 that is formed from a plurality of straps 44, as 
most clearly illustrated in FIG. 2. The seat straps 44 are mounted to the 
seat frame 40 in a spaced-apart relationship. Similar to the backrest 
straps 30, the seat straps 44 are preferably formed from a plastic 
material that stretches to a small degree when a force is applied but 
returns to the original shape when the force is removed. 
The reclining chair 10 has a seat cushion 48 that is positioned on the seat 
support surface 46. The seat cushion 48 preferably has an expanded foam 
core that is covered with a durable waterproof covering material. One of 
ordinary skill in the art will appreciate that the expanded foam core and 
the covering material may be varied depending on the intended use for the 
reclining chair of the present invention. 
A backrest cushion 50 is slidably mounted on the backrest 14 adjacent the 
backrest support surface 32. Similar to the seat cushion 48, the backrest 
cushion 50 is constructed from an expanded foam core that is covered by a 
durable waterproof covering material. While the present invention is 
described with respect to mounting cushions on the seat 12 and the 
backrest 14, other seating surfaces may be used without departing from the 
scope of the present invention. 
The mounting of the backrest cushion 50 on the backrest 14 allows the 
backrest cushion 50 to slide longitudinally with respect to the backrest 
14 as the backrest 14 is pivoted with respect to the seat 12. More 
particularly, the backrest cushion 50 slides toward the seat cushion 48 in 
direct relationship to the degree to which the backrest 14 is reclined 
with respect to the seat 12. 
Sliding the backrest cushion 50 towards the seat cushion 48 allows a 
person's back (not shown) to be maintained at a constant position relative 
to the backrest cushion 50. Because the person's back is maintained at a 
constant position relative to the backrest cushion 50, the reclining chair 
10 of the present invention does not cause skin shear on the person's 
back. 
A pair of belts 54 preferably retain the backrest cushion 50 on the 
backrest 14 and allow the backrest cushion to slide with respect to the 
backrest 14 as the backrest 14 is pivoted with respect to the seat 12. The 
belts 54 are preferably either sewn to the backrest cushion 50 or attached 
to the backrest cushion 50 using a removable fastening device such as a 
VELCRO fastener. The belts 54 preferably encircle the backrest 14 in a 
generally longitudinal orientation so that the belts 54 pass over the top 
and bottom members 22, 26 of the backrest frame 20. 
Each belt 54 is attached to the seat frame 40. Attachment of the belts 54 
to the seat frame 40 causes the belts 54 to vertically slide with respect 
to the backrest 14 as the backrest 14 is pivoted with respect to the seat 
12. The belts 54 are preferably removably attached to the seat frame 40 
using loops 60 that are formed at opposite ends 62 of each belt 54. 
The ends 62 of each belt 54 are preferably attached to the seat 12 using a 
belt retaining mechanism 70. The point at which the ends 62 are attached 
to the seat 12 is referred to as a fixed point 68 because this point does 
not move as the backrest 14 is pivoted with respect to the seat 12. 
The belt retaining mechanism 70 preferably includes a substantially 
cylindrical member that is bent to form a vertical portion 74 and a 
horizontal portion 76. The cylindrical member is attached to the seat 
frame 40 through the vertical portion 74. An enlarged end portion 78 is 
attached to an end of the horizontal portion 76 opposite the vertical 
portion 74. 
The loops 60 are formed with a size that is greater than the horizontal 
portion 76 and the enlarged end portion 78. This configuration allows the 
loops 60 to be moved over the enlarged end portion 78 and then onto the 
horizontal portion 76. Once the loop 60 is moved onto the horizontal 
portion 76, the enlarged end portion 78 prevents the ends 62 from sliding 
laterally off the belt retaining mechanism 70. 
To retain the belts 54 at a desired location on the top section 22, the top 
section 22 preferably includes a belt guide 80 for each belt 54. The belt 
guide 80 allows the belt 54 to slide longitudinally with respect to the 
backrest 14 while preventing the belt 54 from sliding laterally on the 
backrest 14. 
The reclining chair 10 also preferably includes a tilt mechanism 100 that 
controls the pivoting of the backrest 14 with respect to the seat 12. Once 
the backrest 14 is in a desired position with respect to the seat 12, the 
tilt mechanism 100 retains the backrest 14 in the desired position. One 
suitable structure for the tilt mechanism 100 is a piston and cylinder 
structure where one end of the structure is attached to the bottom member 
26 of the backrest frame 20 and the other end of the structure is attached 
to the seat frame 40. 
Operation of the tilt mechanism 100 is controlled by a reclining control 
102. The reclining control 102 is preferably mounted to the backrest frame 
20 to allow the tilt mechanism 100 to be readily operated. The reclining 
control 102 is operable in either an adjusting position or in an engaging 
position. When the reclining control 102 is in the adjusting position, the 
tilt mechanism 100 allows the backrest 14 to pivot with respect to the 
seat 12. When the reclining control 102 is in the engaging position, the 
tilt mechanism 100 prevents the backrest 14 from pivoting with respect to 
the seat 12. Using the engaging position thereby enables the reclining 
chair 10 to be maintained at a selected degree of reclination. 
To assist in moving the reclining chair 10, the reclining chair 10 is 
preferably mounted on a plurality of wheels. The plurality of wheels 
includes a pair of rear wheels 110 that are attached to the seat frame 40 
proximate to an end of the seat 12 where the backrest 14 attaches to the 
seat 12. 
The plurality of wheels also includes a pair of front wheels 112. The front 
wheels 112 are attached to the seat frame 40 at an end of the seat 12 
opposite the rear wheels 110. The front wheels 112 are preferably also 
mounted to pivot about an axis that is normal to rotational axis of the 
front wheels 112. Pivoting of the front wheels 112 allows the reclining 
chair 10 to be moved in a variety of directions. 
The reclining chair 10 further preferably includes a brake mechanism 120 
that is mounted to the seat frame 40. The brake mechanism 120 preferably 
has a brake engaging plate 122 and a pair of brake pads 124. 
The brake engaging plate 122 is operable with an operator's foot. The brake 
engaging plate 122 is preferably configured so that downward pressure on 
the brake engaging plate 122 activates the brake mechanism 120 by moving 
the brake pads 124 into frictional contact with the rear wheels 110 to 
prevent the rear wheels 110 from rolling. Conversely, upward pressure upon 
the engaging plate 122 deactivates the brake mechanism 120 by allowing the 
brake pads 124 to move away from the rear wheels 110. 
The reclining chair 10 also preferably includes side supports 130 that are 
mounted along opposite sides of the seat 12. The side supports 130 help to 
retain a person in a seated position on the reclining chair 10. The side 
supports 130 also preferably include an arm cushion 132 that substantially 
covers an upper edge 134 of the side support 130. The side supports 130 
and the arm cushions 132 are preferably constructed from a frame that is 
covered with expanded foam and then a waterproof plastic covering 
material, which is similar to the covering material used on the seat and 
backrest cushions 48, 50. 
The reclining chair 10 further preferably includes restraining strap guides 
140 that extend from each of the side sections 24. The restraining strap 
guides 140 are adapted to receive a restraining strap (not shown). Using 
the restraining strap in combination with the restraining strap guides 140 
provides additional assistance in retaining a person in a seated position 
on the reclining chair 10. 
In operation, the backrest 14 is initially in an upright position with 
respect to the seat 12, as most clearly illustrated in FIG. 2. Movement of 
the backrest 14 to a reclined position, as indicated by arrow 150, 
increases a distance between the fixed point 68 and the bottom member 26 
which causes the belt 54 to slide downwardly with respect to the backrest 
14, as indicated by arrow 152. Sliding of the belt 54 causes the backrest 
cushion 50 to slide downwardly with respect to the backrest 40, as 
indicated by arrow 154. The backrest cushion 50 moves towards the seat 
cushion 48 in a direct relationship to the degree the backrest 14 is 
reclined. 
Pivoting of the backrest 14 continues until the backrest 14 is in the 
reclined position, as illustrated in FIG. 3. The backrest cushion 50 
preferably slides downwardly approximately 3 inches when moving the 
reclining chair from the upright position to the reclined position. In 
spite of the sliding of the backrest cushion 50 on the backrest 14, an 
upper edge 158 of the backrest 14 preferably remains above the top member 
22 when the reclining chair 10 is in the upright and reclined positions. 
Sliding the backrest cushion 50 on the backrest 14 maintains the backrest 
cushion 50 at a constant position relative to a back of a person who is 
sitting on the reclining chair 10 with the person's back adjacent to the 
backrest cushion 50. As used herein, the phrase "constant position" means 
that the backrest cushion 50 does not slide longitudinally with respect to 
the person's back as the backrest 14 is pivoted from the upright position 
to the reclined position. Sliding the backrest cushion 50 on the backrest 
14 thereby compensates for opening up of an angle between the seat and 
backrest cushions 48, 50. 
Because the backrest cushion 50 is retained in the constant position with 
respect to the person's back, the reclining chair 10 of the present 
invention eliminates skin shear that is associated with prior art 
reclining chairs. By eliminating skin shear, the reclining chair 10 of the 
present invention allows person's with delicate or injured skin to enjoy 
the benefits of using a reclining chair without experiencing discomfort. 
One of ordinary skill in the art will appreciate that the distance the 
backrest cushion 50 must slide to avoid skin shear depends on a variety of 
factors including the thickness of the seat and backrest cushions 48, 50. 
The distance that the backrest cushion 50 slides on the backrest 14 may be 
varied by changing the location of the fixed point 68 with respect to the 
axis 16 and the bottom member 26. For example, the bottom member 26 may be 
offset from the plane of the backrest 14, as most clearly illustrated in 
FIG. 1. 
Although the present invention has been described with reference to 
preferred embodiments, workers skilled in the art will recognize that 
changes may be made in form and detail without departing from the spirit 
and scope of the invention.