Portable automobile partition

A portable partition for use in an automobile having a seat with a seat bench and a seat backrest. The partition includes a seat plate that has first and second portions that rest on the seat bench. The partition also includes a partition plate that has a bottom edge connected to the seat plate between the first and second seat-plate portions. When the seat plate is disposed upon the seat bench, the partition plate is disposed substantially orthogonally of the seat bench. The partition plate typically is constructed of a substantially transparent material so that the driver's view is not obstructed by the partition plate. The partition may also have a hinge joining the first and second portions. The hinge permits the seat plate to more closely fit the seat bench, particularly when a child is seated on a cushion or a child seat placed on top of one or both of the portions of the seat plate. The partition plate typically extends vertically so that its top edge is near to the ceiling of the automobile, and its back edge is shaped to conform to the shape of the seat back. Thus, children respectively seated on a cushion or child seat on top of the two portions of the seat plate are separated from each other by the partition. The partition plate may have a seat-belt passage for receiving an automobile seat belt. Fastening the seat belt through the seat-belt passage secures the partition plate to the automobile seat.

BACKGROUND OF THE INVENTION
 1. Field of The Invention
 The present invention relates generally to automobile passenger-compartment
 partitions, and, more particularly, to an automobile safety partition for
 children.
 2. Related Art
 Children seated in a rear seat of an automobile may engage in squabbling,
 fighting, or other behavior that may be distracting to the driver. Prior
 devices have been developed to separate the children by placing a
 partition between them. For example, U.S. Pat. No. 5,054,837 to Chapman is
 directed to a device that includes a planar panel and "J"-shaped mounting
 members to secure the panel orthogonally of the rear seat. Telescoping
 members may also be used in accordance with Chapman to frictionally engage
 surfaces of the automobile opposed to the seat in order to secure the
 panel in place. Once the panel is secured, children may be seated on the
 automobile seat, with the panel between them.
 Another conventional device with a similar purpose is described in U.S.
 Pat. No. 4,595,227 to Setina. This device is a "Z"-shaped divider that may
 be positioned within an automobile to separate the operator from the
 passengers. The partitioning device of Setina includes a support bar frame
 having two legs that are attached to the floor of the automobile, and a
 roll bar that extends from the top of the support bar to a third leg
 anchored to the floor of the automobile. The front passenger seat
 apparently is removed to accommodate the installation of the device. Other
 conventional devices generally intended to separate passengers in an
 automobile or similar vehicle are listed in Chapman, at column 1.
 SUMMARY OF THE INVENTION
 A disadvantage of some conventional automobile partition devices is that
 they are intended to be permanent or are not easily removable. It often is
 the case, however, that a driver who is transporting children wishes to
 provide a separating partition, but does not wish to install a device that
 will restrict the use of the passenger compartment. For example, older
 children or adults not requiring the partition may also frequently use the
 rear seat. Other conventional devices are intended to be easily removed,
 but still require the use of various attaching mechanisms (such as the
 J-shaped and telescoping mounting members described in the Chapman patent,
 noted above). These attaching mechanisms generally are intended to provide
 stability to the devices, but may add significantly to their weight and
 bulk, and/or to the complexity of their installation. Typically, a driver
 does not wish to carry to and from the vehicle, or store therein, a
 cumbersome mechanism that is difficult to carry or requires substantial
 storage space.
 The disadvantages of the prior art are overcome in one embodiment of the
 portable partition of the present invention for use in an automobile. As
 used herein, the word "utomobile" is to be understood broadly to include
 any type of motor vehicle, including a truck, van, recreational vehicle,
 mobile home, and so on. The automobile has a seat including a seat bench
 and a seat backrest. The partition includes a seat plate that has first
 and second portions structured to rest on the seat bench, and a partition
 plate. Typically, the seat plate is disposed medially on the seat bench
 since an automobile seat bench typically is structured to accommodate two
 people and perhaps a third person in the middle. Therefore, medial
 disposition of the seat plate generally accommodates two children on the
 seat bench. However, in alternative embodiments, the seat plate may be
 disposed elsewhere on the seat bench so that, for example, two children
 may be separated by it on one side of the seat bench and an adult may be
 seated on the other side of the seat bench.
 The partition plate has a bottom edge connected to the seat plate between
 the first and second seat-plate portions. When the seat plate is disposed
 upon the seat bench, the partition plate is disposed substantially
 orthogonal to the seat bench. In some aspects, the partition plate is
 constructed in part of a substantially transparent material. Thus, the
 driver's view is not obstructed by the partition plate.
 In one implementation of this embodiment, the partition also has a hinge
 that joins the first and second portions. The hinge may be made of a
 flexible material, or it may be another type of hinge device. The hinge
 advantageously permits the seat plate to more closely fit the seat bench,
 particularly when a child is seated on a cushion or a child seat placed on
 top of one or both of the portions of the seat plate. The weight of the
 child or children may cause the seat bench to depress, and this depression
 may not be uniform across that portion of the seat bench upon which the
 seat plate is disposed. Thus, without the hinge, one or the other portion
 of the seat plate may rise when the other falls due to depression of the
 seat bench or for other reasons, such as the seat bench not being
 uniformly planar. Alternatively, if two children are seated on respective
 portions of the seat plate, the seat plate may be subject to undesirable
 stresses intermediate the two portions, or a see-saw effect may result,
 particularly if there is a protrusion or some kind of rigid member between
 the two sides of the seat bench. Placement of the hinge intermediate the
 two portions of the seat plate typically reduces or eliminates these
 stresses and effect.
 Advantageously, whether the seat plate is hinged or not, the weight of the
 child or children on the seat plate (seated either in a car seat or on a
 cushion) provides stability to the seat plate. Therefore the partition
 plate is also stabilized because, as noted, its bottom edge is connected
 to the seat plate. Thus, the children themselves, in cooperation with the
 seat plate, act as stabilizing mechanisms for the partition device as a
 whole. In effect, the children replace, or reduce the need for,
 conventional stabilization mechanisms.
 The partition plate may extend vertically so that its top edge is near to
 the ceiling of the automobile. This vertical extension may be
 advantageous, for example, in ensuring that children seated on a cushion
 or car seat on top of seat plate portions on either side of the vertical
 partition plate cannot throw objects over the partition plate. The back
 edge of the partition plate may be shaped to conform to the shape of the
 seat back and to provide that the back edge and the seat back are close to
 each other. For example, it may be determined that a typical automobile
 seat backrest is set at a slightly reclining angle with respect to the
 automobile seat bench. An appropriate implementation of the portable
 partition for use in this kind of automobile thus may include a partition
 plate having a back edge that makes an angle with the bottom edge of the
 partition plate that is slightly greater than ninety degrees. Similarly,
 for automobile seat backrests that are slightly convex, the partition
 plate's back edge may be slightly concave. Close shaping and spacing of
 the back edge of the partition plate with the seat backrest may help to
 keep the children from intruding into the other's space.
 In addition, the proximity of the partition plate and the seat backrest may
 facilitate the optional use, in some aspects of this implementation, of a
 seat-backrest hook. The seat-backrest hook is slidably connected to the
 back edge of the partition plate, and is constructed and arranged so that
 it may engage a top surface of the seat backrest. This optional
 seat-backrest hook provides additional stability to the partition plate
 and may also be used as a handle to carry the partition in its stored
 position. Thus, in contrast to some of the attaching mechanisms used with
 conventional separation devices, the seat-backrest hook of the present
 invention optionally provides additional stability while facilitating
 transport of the device.
 The partition plate may include a track connected to its back edge that
 receives the seat-backrest hook for sliding. The partition plate may also
 have stopping means for selectively fixing the seat-backrest hook in the
 track. Thus, when the seat-backrest hook is moved downward in its track
 until it engages the top of the seat backrest, the partition plate is
 secured from moving away from the seat backrest. In some aspects, the
 depth of the partition plate is substantially coextensive with the depth
 of the seat bench. This feature again may help in preventing one child
 from intruding, or throwing an object, into the space of the other child.
 Where a seat-backrest hook cannot readily be used, ceiling posts may be
 provided to stabilize the partition plate. The ceiling posts may also be
 used with a seat-backrest hook.
 In some implementations, the partition also includes securing means for
 securing the bottom edge of the partition plate to the seat plate. In some
 aspects of these implementations, the securing means is structured so that
 it secures the partition plate substantially orthogonal to the seat plate.
 For example, the seat plate may have a channel between the first and
 second portions that receives the bottom edge of the partition plate, and
 the securing means may include the channel and means for fixing the bottom
 edge of the partition plate to the seat plate when the partition plate is
 disposed within the channel. In some aspects, the securing means may
 include a snap fastener. Similarly, in some aspects of an implementation
 that includes a hinge, the seat plate may have a channel formed at the
 bottom by the hinge and having first and second sides defined by opposing
 edges of the two portions of the seat plate. The bottom edge of the
 partition plate is disposed within this channel.
 In some implementations, the partition plate includes a seat-belt passage
 for receiving an automobile seat belt. Fastening the seat belt through the
 seat-belt passage secures the partition plate to the automobile seat.
 Advantageously, when the partition is not in operation, the first and
 second portions of the seat plate may be rotated about the hinge to a
 portable position such that the first and second portions are
 substantially parallel and adjacent to the partition plate. In some
 aspects of these implementations, securing means are included for securing
 the first and second portions of the seat plate in the portable position.
 In other embodiments, the invention is a child car-seat partition assembly
 for use in an automobile. The automobile has a seat including a seat bench
 and a seat backrest. The assembly includes a seat plate having first and
 second portions, each having an upper surface and each being structured to
 rest on the seat bench. The assembly also includes a partition plate
 having a bottom edge connected to the seat plate intermediate the
 portions. Further included in the assembly is at least one child car-seat
 disposed at least in part upon the upper surface of one of the first and
 second portions. For example, one child car-seat may be disposed at least
 in part upon the upper surface of the first portion, and another
 child-car-seat may be disposed at least in part upon the upper surface of
 the second portion. When the seat plate is disposed upon the seat bench,
 the partition plate is disposed substantially orthogonally of the seat
 bench. In some implementations of these embodiments, the assembly further
 includes a hinge joining the first and second portions.

DETAILED DESCRIPTION
 The attributes of the present invention and its underlying architecture
 will now be described in greater detail with respect to one embodiment
 shown in FIG. 1 and referred to as portable partition 10. Partition 10 is
 shown disposed on an automobile seat 12 having a seat bench 14 and a seat
 backrest 16. Partition 10 includes a seat plate 13 and a partition plate
 19. Children 18 are illustratively shown seated in car seats 15 that rest
 on a seat plate 13. Partition plate 19 has a top edge 11, a back edge 17,
 and a bottom edge 71 (FIG. 7B).
 The seat plate, and other elements of partition 10, are more clearly seen
 in FIG. 2. FIG. 2 is a perspective view of partition 10 without the
 children or car seats and in which backrest 16 is shown in phantom. Seat
 plate 13 includes a first portion 21 and a second portion 22 that each
 rest on seat bench 14. In the illustrated embodiment, seat bench 14 has a
 depth D1, and seat plate 13 has a depth D2 that preferably is
 substantially coextensive with depth D1, although it need not be. This
 arrangement may provide additional stability due to the greater surface
 areas of portions 21 and 22 in contact with seat bench 14 and, in some
 implementations, improved contact between car seats 15 and portions 21 and
 22. However, it will be understood that other arrangements are possible in
 alternative embodiments such that depth D2 is not substantially
 coextensive with depth D1.
 A hinge 25, two implementations of which are described below with respect
 to FIGS. 7A and 7B, joins first and second portions 21 and 22 of the
 illustrated embodiment. Partition plate 19 is disposed at an angle
 .varies. (FIG. 6) with respect to top surface 61 of seat bench 14, and
 portions 21 and 22 which lie substantially parallel to the top surface 61
 of seat bench 14. This angle .varies. typically is 90.degree.. As
 described in greater detail below with respect to FIGS. 7A and 7B, the
 orthogonal position of partition plate 19 with respect to portions 21 and
 22 is maintained by connecting the bottom edge 71 of plate 19 to seat
 plate 13 intermediate portions 21 and 22.
 Advantageously, partition plate 19 of the illustrated embodiment is made of
 a substantially transparent material, such as the LEXAN.RTM. resin made by
 General Electric Company, or any of a variety of clear plexiglass,
 plastics, and other materials. Preferably, the material is durable,
 lightweight, and substantially unbreakable. The transparency of partition
 plate 19 may improve the ability of a driver of the vehicle to see objects
 outside the vehicle, such as by looking through an interior rear-view
 mirror, and to see the children on the seat 12. In other embodiments,
 however, partition plate 19 need not be substantially transparent, or only
 portions of it may be substantially transparent. For example, if seat 12
 is a rearward-facing seat in the rear portion of a station wagon
 automobile, obstruction of the driver's visibility may not be a
 consideration. An opaque partition plate, particularly where driver
 visibility is not an issue, may be used in alternative embodiments so that
 the children cannot visually provoke each other.
 Back edge 17 may be shaped to conform to a typical shape or shapes of seat
 backrest 16. In the illustrated embodiment back edge 17 is shown straight,
 but it need not be so in alternative embodiments. For example, a typical
 automobile seat backrest 16 of one or more types of automobiles may have a
 slightly convex surface upon which passengers rest their backs. Back edge
 17 in alternative embodiments for use with these automobiles therefore
 would have a slightly concave shape. It is assumed that in a typical seat
 12, backrest 16 is orthogonal to seat bench 14. However, it need not be
 so. In some types of automobiles, backrest 16 may be, for example,
 slightly reclined at an angle with respect to seat bench 14. Thus, in
 embodiments for use with these automobiles, back edge 17 would be disposed
 at an angle with respect to the plane of seat plate 13 that is slightly
 greater than ninety degrees. Conforming the shape of plate 19 to the
 arrangement and shape of seat 12 in this manner generally reduces any
 spaces between plate 19 and backrest 16. This closer fit is useful in
 preventing children 18 from touching each other. For a similar reason,
 partition plate 19 typically has a height (i.e., from bottom edge 71 to
 top edge 11) such that its top edge 11 is disposed in closely spaced
 proximity to the interior ceiling (not shown) of the automobile.
 It may be desirable to prevent the movement of partition 10 in a direction
 away from seat backrest 16. For example, if seat 12 is forward-facing,
 partition 10 should be prevented from moving forward in case of a sudden
 stop. In the illustrated embodiment, a seat-belt passage 26 is provided in
 partition plate 19 through which a restraining device, such as a seat belt
 27, may be passed. In the illustrated embodiment, seat belt 27 is a belt
 provided for a third passenger seated in the middle of seat 12. In
 alternative embodiments, one of the seat belts used to secure car seats 15
 and/or children 18 may be passed or looped through seat-belt passage 26.
 For this purpose, passage 26 may include two or more slits or openings,
 one for passing the belt through plate 19 and one for returning the belt
 through plate 19. Alternatively, rather than providing a seat-belt
 passage, a seat belt may be secured to a loop, hook, or any other
 attaching mechanism connected to plate 19 and/or portions 21 and 22.
 Additionally, the illustrated embodiment includes a seat-backrest hook 23
 that further prevents partition 10 from moving forward in a sudden stop.
 As shown in greater detail in FIG. 9, hook 23 may slide in a track along
 back edge 17 of plate 19. In another embodiment, where a seat-backrest
 hook cannot readily be used, ceiling posts 120 may be provided for
 stabilizing the partition, as described more fully below with respect to
 FIGS. 10-12.
 FIG. 3 is a perspective view of partition 10 with cushions 30. Typically,
 this arrangement is suitable for older children who do not use car seats.
 The word "cushions" is to be understood broadly and to encompass, for
 example, any type of seat, padding, or support upon which children 18 may
 sit. The cushions may be made of foam, or another resilient material, and
 may be contoured for seating.
 The cushions are provided for comfort and to distribute a portion of the
 children's weight onto portions 21 and 22 of seat plate 13, shown in
 phantom in their positions under cushions 30. In the illustrated
 embodiment, portions 21 and 22 extend only partially under cushions 30
 (and under car seats 15 as shown in FIG. 1). The weight and bulk of
 partition 10 may thereby be reduced as compared to an alternative
 embodiment in which portions 21 and 22 extend further and therefore are
 larger. In general, the amount by which portions 21 and 22 extend under
 cushions 30 or car seats 15 need only be such that a significant
 percentage of the weight of the children is applied to portions 21 and 22,
 thereby providing stability to partition 10. This percentage typically
 varies depending on a variety of factors that will be appreciated by those
 skilled in the relevant art, such as the weight of the children, the
 structure of the bottom of car seats 15, the rigidity of cushions 30, and
 other factors. In the illustrated embodiment, this percentage is roughly
 33 percent, but it will be understood that it is exemplary only. In some
 embodiments, portions 21 and 22 may extend further so that children 18 may
 be seated directly on them. Typically, portions 21 and 22 in these
 embodiments are made of, or include, a material that is comfortable to sit
 on. Alternatively, or in addition, portions 21 and 22 may be structured
 for comfortable seating. For example, in one implementation of these
 embodiments, a cushion or molded depression may be fashioned into portions
 21 and 22.
 Advantageously, partition 10 of the illustrated embodiment may be folded
 for portability, as shown in FIG. 4. In the portable position of this
 embodiment, portions 21 and 22 are rotated about hinge 25 so that they are
 substantially parallel and adjacent to partition plate 19. In FIG. 4,
 cushions 30 are included in the folded assembly, sandwiched between plate
 19 and portions 21 and 22. In alternative embodiments, cushions 30 need
 not be included in the folded assembly. Any of a variety of conventional
 devices may be used to secure portions 21 and 22 in the folded position.
 Latch 41 is shown in the illustrated embodiment as two hook and loop
 fasteners, one of many examples of such seat-portion securing means. Latch
 41 secures portion 21 to portion 22, but other implementations could
 include means for securing portions 21 and 22 to plate 19. Also, in
 alternative embodiments, various types of lock assemblies may be included
 in hinge 25 to hold portions 21 and 22 in the folded position, one example
 of which is described below in relation to FIGS. 7C and 7D. In the
 illustrated embodiment, seat-backrest hook 23 may be used as a carrying
 handle. As described below with respect to FIGS. 8 and 9, a ratchet track
 91 on back edge 17 of plate 19 prevents hook 23 from sliding upward when
 being used as a carrying handle. In alternative embodiments, any of a
 variety of other conventional techniques may be used to secure hook 23.
 Various hinge mechanisms may be employed to enable portions 21 and 22 to
 move between the portable position and the in-operation position. Two
 exemplary types of hinge mechanisms are now described with reference to
 FIGS. 5, 6, and 7A-7D. FIG. 5 is a side elevational view of partition 10
 in the in-operation position; i.e., disposed so that portions 21 and 22
 rest on seat bench 14. As noted, back edge 17 of plate 19 of the
 illustrated embodiment is spaced in proximity to seat backrest 16. FIG. 6
 is a front elevational view of partition 10 along view line 6--6 of FIG.
 5.
 FIG. 7A is a cross-sectional view of one embodiment of hinge 25, referred
 to as hinge 25A, shown along view line 7--7 of FIG. 5. Portions 21 and 22
 of seat plate 13 include, in this embodiment, hinge arms 76 that extend
 from the main parts 77 of portions 21 and 22 and each form an obtuse angle
 with the planes of their respective main parts 77. Each of arms 76 ends in
 hinge fingers 78 and locking fingers 79. Hinge fingers 78 include holes 70
 for receiving hinge pins 75 around which portions 21 and 22 may rotate
 upward toward plate 19. Pins 75 are secured to a hinge base 72 having an
 upper surface on which hinge fingers 78 rest in a locked position. As
 portions 21 and 22 are lowered into the locked position, locking fingers
 79 engage locking slides 73 that slide within hinge base 72. Slides 73
 thus are urged against locking fingers 79 by a spring 73B disposed between
 locking slides 73. In FIG. 7A, portion 21 is shown in the locked position,
 and portion 22 is shown in the portable position and also, in phantom,
 being lowered from the portable position toward the locked position.
 Slides 73 are connected to, and held in hinge base 72 by, release pins
 73A. When in the locked position, slides 73 are disposed in the spaces
 formed between fingers 78 and 79 respectively, and the tips of fingers 79
 engage base 72. Portions 21 and 22, in this locked position, are prevented
 from rotating upward toward plate 19 by the protrusion of slides 73 into
 these spaces.
 Cushions 30 may be attached to main parts 77 by providing a channel in
 cushions 30 into which main parts 77 may be fitted, as shown in FIG. 7A.
 In some implementations, cushions 30 may include channel liners 30A to
 line the channels so that main parts 77 fit more tightly into the channel
 and may more easily be slipped in and out of the channel, to protect the
 channel from wear, and to perform other functions. Channel liners 30A may
 be made of any suitable material, such as a rigid plastic.
 FIG. 7C is a perspective view of the bottom of partition 10 showing the
 bottoms of portions 21 and 22 and hinge base 72. As shown in FIG. 7C,
 release pins 73A may be squeezed together so that slides 73 are withdrawn
 from the spaces between fingers 78 and 79 and thus portions 21 and 22 are
 free to rotate upward toward plate 19. Plate 19, in this embodiment, may
 be cemented or otherwise fixed into a conforming channel in the top of
 base 72 so that plate 19 is secured substantially orthogonal to the plane
 of main parts 77 of portions 21 and 22 in the locked position. Also shown
 in FIG. 7C is a lever 102 of an exemplary portable-position locking
 mechanism 108 of hinge 25A. FIG. 7D is a crosssectional detail of
 mechanism 108 showing portion 22 in the portable position. As shown in
 FIG. 7D, lever 102 is connected to locking pin 106 so that pin 106 moves
 in a channel of base 72 when lever 102 is moved by a user. Spring 104
 urges pin 106 out of the channel so that it engages a side of the one of
 hinge fingers 78 corresponding to portion 22 when that hinge finger 78 is
 in the portable position. Thus, that one of hinge fingers 78 is sandwiched
 between pin 106 and plate 19 so that portion 22 may be prevented from
 swinging away from plate 19. A similar mechanism 108 is provided with
 respect to portion 21. Thus, when a user wishes to disengage portion 22
 from the portable position, the user moves lever 102 so that pin 106 moves
 toward spring 104 and into the channel provided for it in base 72. Hinge
 finger 78 is thus free to rotate into the in-use position in which it is
 shown in FIG. 7C. A similar technique is used to disengage portion 21 from
 the portable position.
 FIG. 7B is a cross-sectional view of another embodiment of a hinge 25 of
 partition 10, referred to as hinge 25B, along view line 7--7 of FIG. 5. In
 this alternative embodiment, hinge 25B includes a flexible member made of
 a fabric, flexible plastic, rubber, or another suitable flexible material.
 Hinge 25B typically, but not necessarily, has a depth coextensive with
 depth D2 of portions 21 and 22. Hinge 25B has opposing lateral edges El
 and E2 that are respectively attached to portions 21 and 22. A channel is
 formed by opposing edges 74 of portions 21 and 22 of seat plate 13, and by
 the top surface of hinge 25B. Partition plate 19 may be slipped into the
 channel so that its bottom edge 71 abuts the top surface of hinge 25B and
 so that plate 19 is supported by opposing edges 74. Forces W1 and W2 are
 exerted on portions 21 and 22, respectively, due to the weight of children
 18 seated either in car seats 15 or on cushions 30 on top of portions 21
 and 22, or seated directly on portions 21 and 22. Therefore, forces W1 and
 W2 generally prevent the channel between opposing edges 74 from widening
 and stabilize plate 19 in the channel.
 When it is desired to remove partition 10 from the automobile, plate 19 may
 be removed by slipping it out of the channel between opposing edges 74.
 Hinge 25B enables portions 21 and 22 to be folded together, either
 downward (in the direction shown by forces W1 and W2), and/or upward in
 implementations in which the combined thicknesses of portions 21 and 22
 are less than or equal to the width of the channel (or if hinge 25B can
 expand to accommodate the combined thickness). Any of a variety of
 conventional techniques may be used to prevent plate 19 from slipping out
 of the channel. For example, snap fasteners (not shown) may be included
 that protrude from opposing edges 74 into receiving indentations (not
 shown) in plate 19.
 It will be understood that hinges 25A and 25B are exemplary only of the
 many possible types of mechanisms that may be included in hinge 25. For
 example, hinge 25 may also be a piano-type hinge (not shown) with a depth
 substantially coextensive with depth D2 of seat plate 13, or two or more
 smaller hinges of this type spaced along depth D2. The two wings of these
 piano-type hinges would be fixed respectively to portions 21 and 22 of
 seat plate 13.
 In other embodiments, there need not be a hinge 25. Rather, seat plate 13
 may be bonded directly to plate 19. For example, plate 13 may include a
 channel (not shown) formed or cut that is structured to receive bottom
 edge 71 of plate 19. Thus, all of seat plate 13 may be of unitary
 construction, and the opposing sides of the channel may support plate 19
 orthogonally of the seat plate. In these embodiments, plate 19 may be
 fixed in the channel using any known adhesive substance, material, or
 device, or it may be removable. In those implementations in which plate 19
 is removable, any of a variety of conventional techniques may be used to
 prevent plate 19 from slipping out of the channel, as noted above.
 An exemplary embodiment of seat-backrest hook 23 is now described with
 respect to FIGS. 8 and 9. FIG. 8 is a cross-sectional side view of one
 embodiment of seat-backrest hook 23 along view line 8--8 of FIG. 6. FIG. 9
 is a bottom elevational view, along view line 9--9 of FIG. 8, of one
 embodiment of a track 91 of partition 10 along which hook 23 may slide. As
 shown in FIG. 9, back edge 17 of partition plate 19 of the illustrated
 embodiment flares out into a "T" shape. Top portions 91A of the "T" shape
 provide a track around which a track-receiving portion 85 of hook 23 may
 slide. Grabbing portions 95 of track-receiving portion 85 slide behind top
 portions 91A so that hook 23 does not disengage from the track. In the
 illustrated embodiment, periodic indentations 84 are formed or cut into
 back edge 17. Hook 23 includes a flexible handle 86, made of flexible
 plastic, rubber, or another suitable material, that has a tab 82
 protruding from it toward back edge 17. Tab 82 is urged against, and fits
 into, any of indentations 84. For example, tab 82 and indentations 84 may
 be structured in accordance with conventional techniques to form a one-way
 ratchet so that hook 23 may freely slide downward in the direction
 indicated by arrow 88 of FIG. 8. The ratchet structure prevents hook 23
 from moving upward unless flexible handle 86 is pulled away from back edge
 17, thus disengaging tab 82 from one of indentations 84. In this manner,
 hook 23 may be lifted above seat backrest 16, lowered until it engages the
 top of seat backrest 16, and secured in this position by allowing tab 82
 to engage the nearest of indentations 84. Hook 23, and thus partition 10
 to which it is attached, is disengaged from seat backrest 16 by pulling on
 flexible handle 86 to disengage tab 82 and lift hook 23. It will be
 understood that this example is illustrative only, and that many other
 conventional techniques and designs may be used to enable hook 23 to slide
 up and down back edge 17 of plate 19 and to be secured in a particular
 location along back edge 17.
 In some locations or in some types of vehicles, the use of a seat-backrest
 hook 23 may not be possible or desirable. Alternatively, greater stability
 than can be provided by hook 23 alone may be desired. For example, in the
 backseat of many automobiles, the top portion of seat backrest 16 does not
 extend sufficiently far above the shelf below the rear window to permit
 hook 23 to grip backrest 16 sufficiently to provide the desired stability.
 In those instances, it may be desirable to provide some other device for
 stabilizing partition 10. One example of such a stabilizing device is post
 120 illustrated in FIGS. 10-12. In one embodiment, a single post 120, may
 be provided, or as illustrated in FIG. 10, two posts 120 are employed.
 Posts 120 are adjustable, and are designed to engage the ceiling 122 of a
 typical vehicle. Posts 120 may be extended to any length such that when
 partition 10 rests on the seat bench 14, the posts engage ceiling 122.
 In a preferred embodiment, as shown in FIGS. 10-12, each post 120 includes
 two sections, a lower exteriorly threaded shaft 124 and an upper sleeve
 126 with threads about its interior surface which are adapted to mate with
 the threads disposed about the exterior surface of shaft 124. Rotation of
 upper sleeve 126 with respect to shaft 124 adjusts the length of post 120.
 Each post 120 includes an upper pad 128 configured to press against
 ceiling 122. A non-skid coating 145 typically is disposed on the upper
 surface of pad 128 to prevent movement of pad 128 with respect to ceiling
 122. Upper leeve 126 is rotatably mounted in a lower sleeve 130 on pad
 128. Typically, a ball joint 132 is used to permit upper sleeve 126 to
 rotate about its axis. Ball joint 132 also permits pad 128 to pivot with
 respect to upper sleeve 126 to accommodate ceilings 122 of differing
 angles with respect to bench 14.
 The lower end of shaft 124 is non-rotatably mounted in a sleeve 134.
 Preferably, shaft 124 is retained within sleeve 134 by an O-ring 136 which
 rides in a correspondingly formed slot in the interior surface of sleeve
 134 or by other known mechanisms. O-ring 136 permits shaft 124 to be
 snapped in and out of sleeve 134. Preferably, shaft 124 includes ears 144
 that extend into slots 135 in sleeve 134 to prevent rotation of shaft 124.
 Post 120 may be mounted on the top edge 11 of partition plate 19 in any
 known manner. In a preferred embodiment, as shown in FIG. 11, each sleeve
 134 is fixedly mounted on a U-shape member 142 mounted on top edge 11.
 Member 142 may be glued, bolted or affixed in any other way to top edge 11
 of plate 19. In an alternative embodiment, each sleeve 134 may be affixed
 to a slide (not shown) which rides within a slot in member 142. In this
 manner, the location of each post 120 may be adjusted along the top edge
 11 in a front-to-back position.
 Preferably, in this embodiment, a U-shaped base 146 is disposed on bottom
 edge 71 of partition plate 19 as shown in FIG. 11. Base 146 may be glued,
 bolted or affixed in any other way to plate 19. Base 146 tends to broaden
 the area upon which a downward force is applied by partition plate 19 to
 prevent the application of undue stresses to a particularly narrow area of
 the seat bench 14 to prevent ripping or tearing thereof. Preferably, a
 non-skid coating 148 is provided on the lower surface of base 146 to
 prevent movement thereof on seat bench 14.
 In use, typically partition plate 19 is placed on bench 14 with posts 120
 in a retracted position, so that pads 128 are spaced from ceiling 122.
 Back edge 17 is placed flush with backrest 16. Once partition plate 19 has
 been positioned in the desired location on seat bench 14, upper sleeves
 126 of posts 120 are rotated, typically in a counter-clockwise direction
 as shown looking downwardly from ceiling 122 towards bench 14, in FIG. 10,
 to extend upper sleeve 126 upwardly away from partition plate 19. The
 rotation continues until pad 128 engages ceiling 122. Continued rotation
 of upper sleeve 126 applies an upward force Fr on ceiling 122 at the same
 time that a downward force Fb is being applied to,seat bench 14. Rotation
 of upper sleeve 126 is discontinued once the desired force has been
 applied to retain partition plate 19 in the desired location. For removal,
 the process is reversed and upper sleeve 126 is rotated in the opposite
 direction, typically a clockwise direction, as shown looking downwardly
 from ceiling 122 towards bench 14 in FIG. 10, to withdraw shaft 124 within
 upper sleeve 126. Once pads 128 are spaced from ceiling 122, forces
 F.sub.r and F.sub.b have been substantially reduced, partition plate 19
 can be withdrawn from its position.
 Having now described one embodiment of the present invention, it should be
 apparent to those skilled in the relevant art that the foregoing is
 illustrative only and not limiting, having been presented by way of
 example only. Many other schemes for providing a partition plate
 substantially orthogonal to a seat plate, and for securing them, are
 possible in accordance with the present invention. For example, numerous
 variations are contemplated in accordance with the present invention to
 connect a partition plate to a seat plate; enable the seat plate to bend,
 including but not limited to providing a hinge between portions of the
 seat plate; implementing the hinge; secure hinged portions of the seat
 plate in an in-use position, a portable position, or both; provide
 additional support by connecting the partition plate and/or seat plate to
 an automobile seat backrest; and so on. Numerous other embodiments, and
 modifications thereof, are contemplated as falling within the scope of the
 present invention as defined by appended claims and equivalents thereto.