Note: Descriptions are shown in the official language in which they were submitted.
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INTEGRATED PULLOUT STEP SYSTEM FOR
TOP BUNK INGRESS/EGRESS
Reference To Related Apulication and Priority Claim
[ooi1 This application claims the priority of Provisional Patent
Application No. 60/883,087, filed on 02 January 2007, the entire content of
which is incorporated herein by reference.
Field of the Invention
[ooa] This invention relates to a truck having a sleeper cab that contains
an elevated bunk in a sleeper compartment of the cab.
Background of the Invention
[0031 A sleeper cab is one type of truck cab that is produced by truck
manufacturers. For any of various reasons, some truck drivers may prefer to
travel with a partner who may or may not share driving responsibility.
Because of commercial demands that are imposed on long haul professional
drivers, one of two partners who share driving responsibility may drive
while the other sleeps in the cab bunk, which is typically an upper bunk at
the rear of the cab. Some production trucks now have upper and lower
bunks for each of two partners, allowing both to sleep while their truck is
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parked. Ingress to and egress from an upper bunk is typically via a step
ladder.
[0041 A survey of some truckers undertaken by the inventors has
disclosed that a significant number consider the task of climbing into and
out of an upper sleeper cab bunk via a step ladder uncomfortable and/or
inconvenient in at least some respects. Driver age is a factor in the degree
of discomfort with older drivers more likely to find the task more
uncomfortable than younger ones, even to the point of difficulty because
significant upper body strength is typically required for climbing up into a
bunk, and full body weight may have to be borne at least temporarily on one
knee during the process.
[0051 Consequently, it is believed that improvements that can facilitate
ingress to and egress from an upper sleeper cab bunk would be beneficial,
especially when statistics show a trend of increasing average age for
professional truck drivers. Moreover, if such improvements can be
integrated with other components typically found in a sleeper cab, certain
advantageous synergies can result.
Summary of the Invention
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[006] Generally speaking, the present invention relates to a novel
arrangement for a set of stairs that enable a person to step up into an upper
sleeper cab bunk instead of climbing up a ladder.
[0071 The set of stairs associates with a cabinet that provides storage
space for personal possessions of a truck driver, and a passenger or partner,
andlor equipment that is useful in operating the truck. The association of the
set of stairs with the cabinet allows the stairs to nest in a non-deployed
position inside the cabinet when not in use, yet to be easily pulled out from
the cabinet to allow a person to climb up and down them for getting into and
out of an upper bunk.
[oo81 In one embodiment of the invention, the set of stairs carries with
it one or more sliding drawers. In another embodiment, the cabinet, instead
of the set of stairs, has one or more sliding drawers that stay with the
cabinet
when the stairs are slid out for use.
[009] The invention addresses potential safety-related concerns, such as
might be considered in the event of a collision. Because the set of stairs is
substantially outside the cabinet interior when deployed for use, the
disclosed embodiments of the invention comprise certain features that
provide reasonable restraint of the deployed set of stairs in case of an
accident so that the stairs do not become the source of a second collision
inside the cab.
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[ooio] Nominal restraint for the stairs is provided by a two-rail, floor-
mounted track system on which the stairs can slide into and out of the
cabinet. A particular type of track, such as RollOn's "Easy Rail" system, is
preferred because its inherent design prevents the set of stairs from
separating and coming out of the rails as a result of certain unusual loads,
such as might be experienced during a collision. This particular floor-
mounted track system uses roller bearings to facilitate movement of the set
of stairs into and out of the cabinet, an important consideration when the
truck is parked on an inclined surface. The rails extend from the interior of
the cabinet and out into the interior cab space in the sleeper compartment.
They are mounted so as not to protrude in any significant way and while
they are exposed, they are not prominent and can be covered by brushes to
resist intrusion of dirt and foreign objects. The rails ensure facile linear
motion of the set of stairs even though a person moving them may exert
pulling or pushing force a significant distance above the floor that also
creates a torque moment about the floor.
[ooii] Drawers occupy open drawer spaces provided either on the
interior of the set of stairs in one embodiment or on the interior of the
cabinet in another so that there is no significant interior space lost by
providing the set of stairs for climbing into and out of the upper bunk. The
drawers and the set of stairs can be pushed into and pulled out from the
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cabinet independently of each other. By allowing the set of stairs to be
pulled out without also pulling the cabinet-mounted drawers out with them,
as in one of the two embodiments, the pulling force can be smaller because
the weight of the drawers and their contents remain borne by the cabinet,
not by the set of stairs.
[0012] Possible impact of the drawers and stairs during normal use and
in the event of a collision is another concern that is addressed by the
present
invention. The cabinet is mounted directly to the floor of the cab. When the
drawers are mounted for sliding in and out on the cabinet, they are mounted
in a manner that is without interference with the stairs. When the drawers
are mounted for sliding in and out on the set of stairs, they are separated
from the cabinet by the set of stairs, and the set of stairs can freely slide
in
and out of the cabinet.
[0013] In order to provide increased lateral stability of a drawer should
a collision occur while the drawer is open, a certain type of drawer slide,
specifically a full extension drawer slide, such as the Accuride C3732-16P
drawer slide, is preferred. Such a drawer slide allows easy access to items
that may be in the rear of an open drawer and maintains desired structural
integrity of the drawers and cabinet. The slide also possesses a slim profile
that allows for the largest possible drawer to fit in the cabinet drawer
space.
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Each drawer is supported by two slides, one at each side, and can be
constructed to provide a capacity for holding up to 200 pounds.
[0014] While the cabinet could have open storage space instead of
drawers, the presence of drawers is believed to allow the driver and
passenger to better organize their belongings. Moreover, drawers are better
suited than open spaces for keeping stored items in the cabinet. Not all the
cabinet space need have drawers; some open space can be left as closet
space to allow for hanging items such as clothes on a clothes bar.
[0015] In order to prevent the drawers from unintentionally sliding out
when the truck is in motion or when the set of stairs is being moved, a
drawer locking system is preferably provided. For example in the
embodiment where the drawers slide on the cabinet, the drawer locking
system includes clasps on the drawers and a rod attached to the back of the
cabinet. When a drawer is fully closed, the rod is forced into the clasp. The
added interference of the rod and clasps will keep the drawers in place when
closed. When a drawer is to be opened, additional force is required to pull
the rod out of the clasp. Once free, a drawer will slide without any
interference.
[0016] The inventive arrangement also includes a locking system for
releasably locking the set of stairs both in non-deployed position inside the
cabinet and in deployed position. The locking system that includes a handle
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that is used to unlock the set of stairs and once unlocked, either push or
pull
them in one continuous convenient motion as will be explained at length
hereinafter.
[0017] The locking system is carried by the set of stairs, except for
features that are provided in an adjacent cabinet wall, specifically lock
plates, into which a lock pin of a locking mechanism fits to lock the set of
stairs in deployed and non-deployed positions. The handle is located at the
front of the stairs and is accessible both from the floor as well as from the
elevated bunk.
[0018] The locking mechanism is located on the interior of the set of
stairs at the rear. The handle is exterior to the stairs and attached to a
vertical shaft that is located at the front of the set of stairs and extends
from
inside the set of stairs through a hole in the top step to the handle. The
shaft
is turned about its own long axis by pushing or pulling on a grasping portion
of the handle that is disposed off center to the shaft axis.
[0019] A rod, or link, couples the turning motion of the shaft to the
locking mechanism to operate the lock pin, causing the lock pin to retract
from a lock plate in a direction that is transverse to the direction in which
the set of stairs move into and out of the cabinet. Retraction of the lock pin
is accomplished via an interaction between posts on the lock pin and cam
grooves in a rotor that turns within the locking mechanism in correlation
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with the turning of the shaft by the handle by virtue of the rod coupling the
shaft motion to the locking mechanism.
[0020] The cam grooves are symmetric in a way that causes the fully
extended lock pin to retract both when the handle is turned 90 clockwise
from a center, or home, position and when the handle is turned 90
counterclockwise from the center position. By allowing both directions of
turning to unlock the set of stairs, the locking system allows a person's
natural pulling or pushing action on the handle to initially unlock the stairs
and then either pull them out from the cabinet from non-deployed position
or push them into the cabinet from deployed position. A spring in the
locking system biases the system toward the locked condition so that when a
person releases the handle with the set of stairs in either the deployed
position or the non-deployed position, the lock pin automatically locks the
stairs.
[0021] A final weight of about 56 pounds for the set of stairs can require
as little as 6.8 pounds of force even on a 7 degree incline. Once the stairs
have been pulled out and locked into place, the steps present a 15 inch width
to a person climbing up or down them, a dimension the inventors consider
adequate for ascent and descent. This width also takes into account the
necessity for the stairs to fit into the cabinet, which in the interior
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arrangement of the illustrated cab is located adjacent an end of the bunk
with the cabinet back against a side wall of the cab.
[0022] A step depth of around 12 inches is considered appropriate when
certain ergonomic factors are taken into account. Because a person is likely
to turn around on the top step in order to sit on the bunk, that step should
have a depth larger than the lower steps. Considering the possibility that a
person using the stairs may be bare-footed or wearing only stockings, it is
also preferred that the individual steps have a suitable friction surface,
such
as friction strips.
[00231 The invention also addresses potential concems about apparent
loss of storage space. While the space devoted to the cabinet is occupied by
a refrigerator in some truck models, the benefits of the cabinet/drawer/stair
system of the present invention may outweigh the loss of refrigerator space
in a significant number of minds. Not all large trucks necessarily have a
refrigerator in that location, and many have no refrigerator at all.
[0024] While some storage space may be lost due to the presence of the
stairs, the volume of the stair material is rather small, and can be as
minimal as about one cubic foot.
[0025] Because the presence of drawers affords individuals the
opportunity for better organizing their belongings and making them easier
to find, the invention may encourage drivers to travel in pairs, and that
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could reduce delivery time of goods to customers, and possibly increase the
number of individuals that want to be a truckers if a friend, family member,
or partner can accompany them on long hauls.
[0026] The technological factors of better ergonomics (which come
inherently with the introduction of steps), storage with improved utility (as
discussed), and concern for the safety and well-being of the truck driver are
embodied in principles of the invention.
[0027] Not having to store personal items in overhead compartments
creates a more homelike atmosphere. The inventive stair system allows the
stairs to be moved out of the way and essentially out of sight when not used,
unlike a ladder or permanent footholds that are commonly present.
[0028] Because the steps provide larger areas on which a person can
step, the necessity for precise foot placement is avoided. Furthermore, the
steps allow a person to maintain his/her center of gravity over a step while
also providing the option of standing on both feet on the same step
simultaneously. The added depth of the top step allows the user to easily
turn around to facilitate entry into and exit from the bunk.
[0029] The flat horizontal top of the cabinet provides continued use as a
platform for objects such as a television or appliance.
[0030] A general aspect of the invention relates to a truck comprising a
sleeper cab having a bunk that is elevated from a floor of the cab. A cabinet
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is adjacent an end of the bunk. A track runs on the cab floor from inside the
cabinet to outside the cabinet. A set of stairs are movable along the track
from a non-deployed position inside the cabinet to a deployed position that
allows a person to ascend and descend the stairs for climbing up into and
climbing down from the bunk.
[0031] More specific aspects relate to various features that have been
discussed above and will be described in more detail below.
[0032] The foregoing, along with further features and advantages of
the invention, will be seen in the following disclosure of a presently
preferred embodiment of the invention depicting the best mode
contemplated at this time for carrying out the invention. This specification
includes drawings, now briefly described as follows.
Brief Description of the Drawings
[0033] Figure 1 is a perspective view partially cut away to show the
interior of a sleeper cab of a highway truck that has a pullout step system
that embodies principles of the present invention.
[0034] Figure 2 is a perspective view of a first embodiment of step
pullout system that embodies principles of the present invention and shows
the steps in non-deployed position.
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[00351 Figure 3 is a view like Figure 2 but with the steps in deployed
position.
[00361 Figure 4 is an enlarged fragmentary perspective view of a
portion of Figure 3 showing more detail.
[00371 Figures 5, 6, and 7 are respective front, side, and top views of a
cabinet base that can be seen in Figure 2.
[00381 Figures 8, 9, and 10 are respective front, side, and top views of a
set of stairs that are shown in Figures 2 and 3.
[0039] Figures 11, 12, and 13 are respective front, side, and top views
of a top cabinet section that can be seen in Figures 2 and 3.
[0040] Figures 14, 15, and 16 are respective front, side, and top views
of a drawer that can be seen in Figure 2.
[0041] Figure 17 is an enlarged fragmentary view showing a locking
system for locking the set of stairs in deployed and non-deployed positions
and that includes a handle that is used both to unlock the set of stairs and
to
move them between deployed and non-deployed positions.
[0042] Figure 17A is a perspective view of the locking system by
itself apart from the stairs.
[0043] Figure 18 is a perspective view of a locking mechanism of the
locking system.
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[0044] Figure 18A is a perspective view for showing the interior of
the locking mechanism.
[0045] Figures 19, 20, and 21 are respective top, front, and side views
of one of the parts of the locking mechanism of Figure 18.
[0046] Figures 22, 23, and 24 are respective top, front, and side views
of a second part of the locking mechanism of Figure 18.
[0047] Figures 25, 26, and 27 are respective front, side, and top views
of a third part of the locking mechanism of Figure 18.
[0048] Figure 28 is a perspective view of a second embodiment of step
pullout system embodying principles of the present invention showing the
set of stairs in non-deployed position.
[0049] Figure 29 is a perspective view of the second embodiment of
step pullout system looking in a different direction still with the stairs in
non-deployed position but with a drawer open.
[0050] Figure 30 is a perspective view looking in the same direction
as Figure 28, but with the stairs in deployed position.
Description of the Preferred Embodiment
[0051] A first embodiment of pullout step system 40 embodying
principles of the present invention is presented in Figures 1-27 to show a set
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of stairs 42 that can be selectively placed in a non-deployed position shown
in Figure 2 and a deployed position shown in Figures 1 and 3.
[00521 Stairs 42 comprises a module (see also Figures 8-10) that
comprises first, second, and third solid rectangular steps, 44, 46, 48
respectively, in ascending order, solid rectangular risers 60, 62, 64 and a
solid rectangular side wa1158.
[0053] A bar 50 is disposed at the front of the module as viewed in
Figures 8 and 9 to join the bottom of riser 60 to the bottom of wall 58. A
bar 52 is disposed at the front of the module to join the junction of step 44
and riser 62 to wall 58. Step 46 is the left hand end portion of a horizontal
wall 54 that continues to the right to join with wall 58, and riser 64 is
supported on that horizontal wall. Step 48 joins the top of riser 64 to side
wall 58. The arrangement of steps, risers, bars, and side wall provides the
module with three rectangular-shaped interior spaces 66, 68, 70 that are
closed on the sides but open at front and rear. On the interior of the module,
the top of space 66 is open to the bottom of space 68, but the top of space 68
is closed to the bottom of space 70. The bottom of space 66 is open to the
cab floor 72.
[00541 Additional features include a suitable friction surface on each
step, shown by friction strips 74, and vertical flanges 76, 78, 80, whose
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purpose will be explained later, extending a short distance upward from the
rear edge of respective steps as viewed in Figures 8 and 9.
[0055] System 40 also comprises a cabinet base 82 that is shown by
itself in Figures 5-7 and that comprises structure that forms two rectangular-
shaped interior spaces 84, 86 that are open at least at the front and
optionally at the rear. The specific base shown here has at least solid walls
88, 90, 92, 94, and 95, with wall 90 extending to wa1195.
[0056] System 40 further comprises a top cabinet section 96 that is
shown by itself in Figures 11-13 and that comprises structure that forms two
interior spaces 98, 100. At least space 98 is open at the front and optionally
at the rear. This particular top section has the two spaces open at both front
and rear and has solid walls 102, 104, 106, 108.
[0057] The two cabinet sections 82, 96 are arranged to vertically capture
stairs 42 between themselves while allowing the stairs to slide into and out
of a cabinet 110 cooperatively formed by the two cabinet sections.
[00581 Wall 108 is a stepped wall that is substantially congruent to the
three steps 44, 46, and 48 and the two risers 62, 64. When stairs 42 are in
non-deployed position inside cabinet 110, step 44 is disposed directly below
a horizontal portion 112 of wall 108, step 46 is disposed directly below a
horizontal portion 116 of wall 108, step 48 is disposed directly below a
horizontal portion 120 of wall 108, riser 62 is disposed directly to the right
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of a vertical portion 114 of wall 108, and riser 64 is disposed directly to
the
right of a vertical portion 118 of wall 108.
[0059] When stairs 42 are in non-deployed position inside cabinet 110,
step 44 directly overlies wa1190, the horizontal wall 54 that contains step 46
directly overlies wall 94, and wall 58 directly faces the inside of wall 95.
The stepped wall 108 cooperates with top and side walls of the top cabinet
section to provide space within the interior of the top cabinet section.
although the drawing Figures show the front of such storage space closed, it
can be left open and provided with drawers, shelves, and/or a clothes closet.
[0060] Space 84 provides a drawer space for a drawer 124, and space
86, a drawer space for a drawer 126. (See Figure 2.) Drawer 124 is shown
by itself in Figures 14, 15, and 16. The drawers are mounted on base 82 by
drawer slides, having elements such as 128, 130 in Figure 2, that are
attached to the drawer sides and that slide on elements mounted on the
confronting vertical walls of the base. Drawers 124, 126 are spaced
vertically apart at the front so that bar 52 can fit between them when the
stairs are in non-deployed position. It can be seen that drawer space 84 and
its drawer 124 underlie all three steps 44, 46, 48, and a drawer space 86 and
its drawer 126 overlie drawer space 84 and its drawer 124 and underlie the
second and third steps 46, 48.
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[00611 Figure 1 shows a truck 136 having a sleeper cab 138 with a
bunk 140 that is elevated from floor 72 arranged with its length running in
the direction of the cab's width at the rear of the cab. Cabinet 110 is
mounted on floor 72 behind a passenger seat 142 with the cabinet rear, or
back, disposed against a side wall 144 of the cab. Base 82 is fastened to
floor 72. A track that comprises floor-mounted parallel rails 146, 148 (See
Figure 2.) supports stairs 42 so that the stairs are free of interference with
base 82 vertically and horizontally. The track length runs in the direction of
the cab's width parallel to the length of bunk 140 from inside the cabinet
and ends in the open interior of the cab.
[00621 A lower bunk 149 is beneath bunk 140. It is alongside bunk 149
that stairs 42 slide into and out of cabinet 110. Figure 1 shows stairs 42 in
deployed position (also shown in Figure 3) that allows a person to ascend
and descend them for climbing up into and climbing down from bunk 140.
It should be noticed that drawers 124, 126 stay behind in base 82 when
stairs 42 are slid out of cabinet 110 to the deployed position. In non-
deployed position of the stairs, drawers 124, 126 can be opened and closed
free of interference with the stairs, as shown by Figure 2.
[00631 With the set of stairs deployed, inner portions of the three steps
effectively remain inside the cabinet. The weight of the stairs and a person
using them must be transferred to floor 72 in some way. Some of that
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weight is transferred through wall 58 and rail 148, and through riser 60 and
rail 146. The remainder of the weight is transferred by the inner portion of
step 44 that effectively remains inside the cabinet and bears on wall 90,
particularly when the weight of a person is on the stairs, and possibly also
by the inner portion of step 46 and its wall, bearing on wall 94. With the
lower surfaces of steps 44 and 46 confronting upper surfaces of walls 90
and 94, some limited sliding of the former on the latter as the stairs are
slid
out of and into the cabinet is tolerable in order for the hidden inner
portions
of the two steps to be supported when the stairs are used.
[0064] A locking system 150, shown in various Figures, and especially
in Figures 17 through 27, releasably locks stairs 42 in both deployed and
non-deployed position. Locking system 150 comprises a locking mechanism
152 mounted on wa1154 inside of wa1158 at the rear of the stair module. A
vertical shaft 154 at the front of the interior of the stair module alongside
wall 58 is journaled for rotation about is own axis on an assembly 156
mounted on wall 54 to the front of locking mechanism 152. Shaft 154
extends through a hole at a front corner of step 48 where a handle 158
attaches to the shaft end. A rod, or link, 160 connects a short post 162 on a
rotor 164 in assembly 156 that can be turned by shaft 154 to a short post
166 on a rotor 168 of locking mechanism 152.
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[0065] Figures 17 and 17A show locking system 150 in locking position
that places a lock pin 170 of mechanism 152 in a maximally extended
position as can be seen in Figures 17A, 18, and 18A. With stairs 42
positioned in deployed position at their maximum distance out from cabinet
110 on rails 146, 148, the distal end of maximally extended lock pin 170
protrudes through a hole in wall 58 to lodge in an aligned hole in a lock
plate (not shown) that is affixed to wall 106 of the top cabinet section to
thereby lock stairs 42 stationary on the track. With stairs 42 fully slid into
cabinet 110, the distal end of pin 170 can protrude through the hole in wall
58 to lodge in another aligned hole in another lock plate (not shown) that is
also mounted on 106 to thereby lock the stairs stationary on the track in
non-deployed position.
[0066] Handle 158 is essentially a hand crank. It has a vertical grasping
portion 172 that joins with shaft 154 via a horizontal lever arm portion 174.
The extent to which lock pin 170 extends from mechanism 152 is controlled
by the extent to which shaft 154 is turned by handle 158. With handle 158 in
the position shown in Figures 3 and 17, lock pin 170 is maximally extended.
If handle 158 is grasped and turned 90 either clockwise or
counterclockwise from the Figures 3 and 17 position, pin 170 will be
maximally retracted. With pin 170 maximally retracted, it cannot lock the
stairs to either lock plate.
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[0067] Rotor 164 turns in correlation with the turning of shaft 154 by
handle 158. Link 160 couples the motion of rotor 164 to rotor 168 so that
rotor 168 also turns in correlation with the turning of shaft 154 by handle
158.
[0068] How rotor 168 extends and retracts lock pin 170 is explained
with reference to Figures 19-27. A square casing 180 of locking mechanism
152 has a hole in one side that guides pin 170 for linear extension and
retraction. Casing has a circular cavity in which rotor 168 is disposed. Rotor
168 has an upper part 168U and a lower part 168L. It is part 168U that
contains post 166.
[0069] The rotor parts 168U, 168L mutually abut at respective identical
plateaus 182, 184 that provide space that allows the parts to cooperate in
capturing lock pin 170 between them. With the two parts abutted, a post 186
on the bottom of lock pin 170 at the pin's proximal end fits in a cam groove
188 on an interior face of part 168L. Similarly a post 190 on the top of lock
pin 170 at the pin's proximal end fits in a cam groove 192 on an interior
face of part 168U. The two cam grooves are identical and are in
circumferential registration. Each groove has symmetrical half segments
that merge at a maximum radial distance 193 from the center of its circular
rotor part. Each half segment ends at a minimum radial distance from the
center of its rotor part. The minimum radial distances are on opposite halves
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of a common diameter 195 of the rotor. The maximum radial distances 193
are at right angles (90 ) to that common diameter.
[0070] With lock pin 170 so constrained between the two rotor parts
168U, 168L and with posts 186, 190 located in the cam grooves at the
maximum radial distance 193, the lock pin is maximally extended,
corresponding to the position of parts shown in Figure 17.
[0071] Turning rotor 168 in either direction within casing 180 will cause
the cam grooves to also turn. As posts 186, 190 ride in the respective cam
grooves, the camming action of the grooves on the pin posts 186, 190
causes lock pin 170 to retract. Full retraction occurs when the rotor has
turned 90 in either direction.
[0072] The process of how the association of handle 158 with locking
system 150 enables stairs 42 to be operated can now be fully understood.
The wall structure of top cabinet section 96 has an exterior recess 194 at an
upper corner that is open toward the bunk on one side and toward the
interior of the cab on an adjoining side. Handle 158 is disposed within
recess 194, and hence doesn't noticeably protrude when the stairs are in
non-deployed position, but it can still be conveniently grasped.
[0073] With the stairs locked in the non-deployed position, a person
grasping handle 158 and pulling it toward himself or herself, will initially
turn shaft 154 and retract lock pin 170. Once lock pin 170 clears the
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corresponding lock plate, the stairs become unlocked, enabling them to be
slid on rails 146, 148. Consequently with the stairs still non-deployed but
now unlocked, continued pulling on handle 158 will begin moving the stairs
out of the cabinet along rails 146, 148. When the stairs have been placed in
deployed position, returning handle 158 to the position of Figure 17 will
cause lock pin 170 to extend and lock the stairs to the other lock plate. For
automatically locking the stairs upon release of the handle, a spring, such as
a torsion spring 197, can be employed in association with the locking
system to inherently bias the lock pin toward maximum extension. The
spring is fully relaxed when lock pin 170 is fully extended.
[00741 A tail 197A at the upper end of spring 197 fits into a hole in
wall 48 to constrain that end of the spring on the stairs. A tail 197B at the
lower end of the spring runs diametrically through shaft 154. Coils of the
spring are disposed around the outside of the shaft.
[00751 With the stairs locked in the deployed position, a person grasping
handle 158 and pushing it away from himself or herself, will initially turn
shaft 154 and retract lock pin 170. The spring coils will unwind slightly as
the shaft is turned through 90 . Once the lock pin clears the lock plate, the
stairs become unlocked, enabling them to be slid along the track.
Consequently with the stairs still deployed but now unlocked, continued
pushing will begin moving the stairs along rails 146, 148 back toward the
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cabinet. When the stairs have been fully returned to the cabinet, returning
the handle to the position of Figure 17 will cause lock pin 170 to extend and
lock the stairs to the corresponding lock plate. Upon handle 158 being
released, spring 197 relaxes to automatically extend the lock pin and return
the handle to the Figure 17 position.
[0076] When the handle is pulled instead of pushed, the coils of spring
197 wind slightly and provide torque that will return the spring to relaxed
condition, and handle to Figure 17 position, upon release of the handle.
[00771 Although the locking system, with the exception of handle 158 is
contained within the interior space 70, it is desirable that the moving
elements in that space be covered when the front of the space is left open.
Figure 17 shows a cover in phantom for covering assembly 156, mechanism
152, and rod 160.
[00781 The intent of flanges 76, 78, and 80 is to interfere with structure
of the top cabinet section so as to prevent the set of stairs from coming
straight out of the cabinet if the stairs run off the end of the track for any
reason. The interference would occur only if the stairs were to move further
out of the cabinet beyond the deployed position.
[00791 A second embodiment of pullout step system 240 embodying
principles of the present invention is presented in Figures 28-30. Like
system 40, system 240 has a set of stairs 242 that can be selectively placed
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in a non-deployed position inside a cabinet 310 shown in Figures 28 and 29
and a deployed position shown in Figures 30 through 32.
[00801 Stairs 42 comprises a module 243 that comprises first, second,
and third solid rectangular steps, 244, 246, 248 respectively, in ascending
order, solid rectangular risers 260, 262, 264 and a solid rectangular side
wall 258. Steps 244 and 246 are external portions of solid horizontal walls
that extend through the interior of the module to join to side wal1258.
[00811 The arrangement provides the module with three rectangular-
shaped interior spaces that are closed on the sides but open at front and
rear.
[00821 Each step has a suitable friction surface and vertical flanges that
cannot be seen but are like and function in the same way as flanges 76, 78,
80 of the first embodiment.
[00831 Drawers 324, 326 are arranged to slide in and out of a first and
second of the three spaces via drawer slides in the same way that drawers
124, 126 can slide on base 82 of the first embodiment. Because the drawers
324, 326 are mounted for sliding on the stair module, they will move with
the stairs. The third space 270 is open at the front.
[0084] With the stairs not deployed, as in Figures 28 and 29, the
drawers can be opened and closed. Likewise with the stairs deployed as in
Figure 30, the drawers can still be opened and closed.
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[00851 The track and the locking system of the second embodiment are
like that of the first embodiment. The cabinet 310 basically fits over the set
of stairs and is fastened to the floor at the bottom of its side walls or at
the
back to the cab side wall.
[0086] While a presently preferred einbodiment of the invention has
been illustrated and described, it should be appreciated that principles of
the
invention apply to all embodiments falling within the scope of the invention
that is defined as follows.
