fig1 - 3 are schematic views illustrating an embodiment of a highchair assembly 100 . the highchair assembly 100 can include a seat frame 102 , a plurality of leg extensions 104 , a booster seat 106 and a tray 108 . the seat frame 102 , leg extensions 104 , booster seat 106 and tray 108 can be assembled together to form a highchair . the highchair configuration as shown in fig1 can be suitable for receiving a young child , who can sit in the sitting area defined by the booster seat 106 . as shown in fig3 , the booster seat 106 can be provided as a detachable seat , which can be removed according to the needs . fig4 is a schematic view illustrating another configuration of the highchair assembly without the booster seat 106 installed thereon . in this configuration , the leg extensions 104 are attached to the seat frame 102 to form a highchair . unlike the highchair configuration of fig1 , the sitting area of the highchair configuration shown in fig4 is defined by the seat frame 102 , and is a larger than the sitting area of the booster seat 106 . accordingly , the highchair configuration shown in fig4 may be suitable for seating an older child . fig5 - 7 are schematic views illustrating other configurations of use that may be set with the seat frame 102 , leg extensions 104 , booster seat 106 and tray 108 . fig5 and 6 are schematic views illustrating a configuration in which the booster seat 106 can be independently used on an adult chair . referring to fig5 , when it is removed from seat frame 102 , the booster seat 106 with the tray 108 mounted thereon can be placed on an adult chair for use as an infant feeding booster seat . as shown in fig6 , the tray 108 may be removed from the booster seat 106 so as to leave more room for receiving a taller child on the booster seat 106 . fig7 is a schematic view illustrating another configuration in which the seat frame 102 and the tray 108 are respectively converted to a standalone chair and a standalone table . in this configuration , the tray 108 is detached from the booster seat 106 , and the leg extensions 104 are removed from the seat frame 102 and attached to the tray 108 . the coupling of the tray 108 with the leg extensions 104 can form a standalone table . moreover , the seat frame 102 without the leg extensions 104 attached thereto can be used as a standalone chair having multiple legs 120 and 122 capable of standing independently on a floor surface . the height of the seat frame 102 configured as a standalone chair , and the height of the table formed by the assembly of the tray 108 and the leg extensions 104 are respectively smaller than the height of the highchair configurations shown in fig1 and 4 . accordingly , the chair and table configuration shown in fig7 can be easily accessible to a child for play and entertainment . detailed construction of the seat frame 102 , leg extensions 104 , booster seat 106 and tray 108 is described hereinafter with reference to fig8 - 20 . in conjunction with fig1 , fig8 is a schematic view illustrating the seat frame 102 alone . the seat frame 102 can include a seat portion 110 and a support frame portion 112 affixed with each other . the seat portion 110 can have a seating surface 114 for receiving a child , a seatback 116 , and a left and a right sidewall 118 . the seatback 116 and the sidewalls 118 can respectively project upward from the seating surface 114 to define at least partially a sitting area of the seat portion 110 . in some embodiments , the seat portion 110 including the seatback 116 and the sidewalls 118 may be formed as an integral body made of molded plastics . the support frame portion 112 can include a plurality of legs 120 and 122 projecting downward from the seat portion 110 . the legs 120 and 122 can be exemplary formed tubular segments , e . g ., made of a metallic material . the legs 120 can be front legs , and the legs 122 can be rear legs . two brackets 124 can be respectively affixed with the legs 120 below the seat portion 110 . a removable footrest 126 ( better shown in fig1 - 4 ) can be attached to the brackets 124 when the seat frame 102 is used in a highchair configuration . when the seat frame 102 is used as a standalone chair , the footrest 126 can be removed , and the legs 120 and 122 can provide independent standing support on a floor surface . referring to fig8 , the legs 120 and 122 can have lower ends respectively affixed with foot members 128 . the foot members 128 can have a similar structure . fig9 is a schematic view illustrating the construction of one foot member 128 . the foot member 128 can be a plastic part having a pad 130 and an insert portion 132 connected with each other . in one embodiment , the foot member 128 including the pad 130 and the insert portion 132 may be formed as an integral body by plastic molding . when the seat frame 102 is configured as a standalone chair , the legs 120 and 122 can stand on a floor surface with the pads 130 of the foot members 128 in contact against the floor surface . the insert portion 132 can be connected with a resilient tongue 134 having a distal end provided with a knob 136 . when the foot member 128 is assembled with one leg 120 or 122 , the insert portion 132 can be fixedly fitted into the hollow interior of the leg 120 or 122 with the pad 130 exposed outward . moreover , the resilient tongue 134 can be received inside the leg 120 or 122 , and the knob 136 can protrude outward through a hole formed through the leg 120 or 122 for locking engagement with one leg extension 104 . the resilient tongue 134 can act as a latching member for locking one leg extension 104 with the leg 120 or 122 . referring again to fig1 - 3 , the leg extensions 104 can respectively attach to the legs 120 and 122 of the support frame portion 112 for configuring a highchair . each of the leg extensions 104 can be an elongated tube segment having a connecting end 104 a provided with a hole 137 . the length of each leg extension 104 may be greater than that of the legs 120 and 122 . referring to fig1 and 9 , when the leg extensions 104 are attached to the legs 120 and 122 of the support frame portion 112 , the pads 130 of the foot members 128 can be respectively received in the connecting ends 104 a of the leg extensions 104 , and the knobs 136 of the resilient tongues 134 can respectively engage with the holes 137 on the connecting ends 104 a of the leg extensions 104 . the legs 120 and 122 and the leg extensions 104 attached thereto can exhibit an overall smooth profile , and the pads 130 of the foot members 128 can be substantially concealed inside the leg extensions 104 for preventing protruding features that may be undesirable in use . for removing the leg extensions 104 from the support frame portion 112 , the knobs 136 can be pushed inward to disengage from the holes 137 of the leg extensions 104 . the leg extensions 104 can be thereby unlocked , and removed from the legs 120 and 122 . referring again to fig8 , the seat portion 110 can further be affixed with a beam 138 . in one embodiment , the beam 138 can be exemplary formed as a tubular segment , e . g ., made of a metallic material . the beam 138 can extend continuously along a rear and a left and a right side of the seat portion 110 . more specifically , the beam 138 can extend along the respective outer surfaces of the seatback 116 and sidewalls 118 , and can slope downward toward a front of the seat portion 110 at the left and right sides thereof . the seat portion 110 can have a region 110 a extending above the beam 138 at the rear , left and right sides thereof . in one embodiment , the beam 138 may be joined with the legs 120 . the beam 138 can define a support surface for the booster seat 106 when it is installed on the seat frame 102 . in conjunction with fig1 , fig1 - 13 are schematic views illustrating the construction of the booster seat 106 . the booster seat 106 can include a seat portion 140 and a removable backrest 141 . fig1 and 11 show the seat portion 140 and the backrest 141 assembled with each other , fig1 shows the seat portion 140 alone , and fig1 shows the backrest 141 alone . the seat portion 140 can have a bottom portion 142 protruding downward that can provide independent standing support on a floor surface or an adult chair . the seat portion 140 can further have an upper seating surface 144 for receiving a child , a rear wall 146 and a left and a right armrest 148 . the seating surface 144 can have a sitting area that is smaller than that of the seat portion 110 of the seat frame 102 . the rear wall 146 and the armrests 148 can respectively project upward from the seating surface 144 . in one embodiment , the seat portion 140 including the rear wall 146 and the armrests 148 may be formed as a unitary body made of molded plastics . each of the armrests 148 can have an inner cavity 150 that is opened downwardly and is delimited at least partially between an inner sidewall 148 a and an outer sidewall 148 b of the armrest 148 . the inner sidewall 148 a is adjacent to the seating surface 144 , and the outer sidewall 148 b is located at the outer side of the armrest 148 . the outer sidewall 148 b can have a lower edge 152 that rises obliquely toward a rear of the seat portion 140 and lowers toward a front of the seat portion 140 . a top of the rear wall 146 can be connected with a bend portion 153 that extends along a width of the seat portion 140 . the bend portion 153 can at least partially define an inner cavity 153 a that is opened downwardly and respectively connects with the inner cavities 150 of the two armrests 148 . moreover , the bend portion 153 can have a lower edge 154 that is connected with the lower edges 152 of the two armrests 148 . as better shown in fig1 , the seat portion 140 can further include two mount slots 156 for assembling the backrest 141 . the two mount slots 156 can be respectively formed in the armrests 148 ( e . g ., in the inner sidewall 148 a thereof ) near the rear wall 146 . in one embodiment , each of the mount slots 156 can have a t - shape . moreover , the seat portion 140 can be assembled with two latching members 158 that are respectively disposed adjacent to the two mount slots 156 . the two latching members 158 are operable to engage with the backrest 141 for locking the backrest 141 with the seat portion 140 , and to disengage from the backrest 141 for allowing its removal . in conjunction with fig1 - 13 , fig1 is a cross - sectional view illustrating the backrest 141 locked with the seat portion 140 via the latching member 158 . the two latching members 158 can be similar in construction , each of which can include an elongated segment 160 , a bend portion 162 and an actuating portion 164 . the bend portion 162 and the actuating portion 164 can be respectively connected with the elongated segment 160 at two opposite sides thereof . the bend portion 162 can extend generally perpendicular to the elongated segment 160 , and the actuating portion 164 can have a curved shape for facilitating its operating with a finger . moreover , a region of the elongated segment 160 between the bend portion 162 and the actuating portion 164 can be formed with a knob 166 having an angled surface 166 a . in one embodiment , the latching member 158 , including the bend portion 162 , actuating portion 164 and knob 166 may be integrally formed as a single part . the bend portion 162 can be fixedly connected with an interior of the seat portion 140 , and the knob 166 can protrude into an interior of the mount slot 156 associated therewith . the elongated segment 160 can elastically deflect relative to the bend portion 162 to cause the knob 166 to engage or disengage the backrest 141 . referring to fig1 and 14 , the backrest 144 can have two protruding bosses 168 respectively protruding outward at a left and a right side edge 141 a of the backrest 141 near a lower end thereof . each boss 168 can have a t - shape , and can be provided with an opening 168 a . when the backrest 141 is assembled with the seat portion 140 , the two bosses 168 can be respectively inserted into the mount slots 156 . as they slide into the mount slots 156 , the bosses 168 can respectively push against the angled surfaces 166 a of the knobs 166 , which causes respective deflection of the elongated segments 160 of the latches 158 away from the side edges 141 a of the backrest 141 to allow further downward travel of the bosses 168 . once the bosses 168 are fully inserted in the mount slots 156 , the elongated segments 160 can elastically deflect toward the side edges 141 a of the backrest 141 to cause the knobs 166 to respectively engage with the openings 168 a of the bosses 168 . the latches 158 can thereby block upward displacement of the backrest 141 , and the backrest 141 can be locked with the seat portion 140 . for removing the backrest 141 , the actuating portion 164 can be pulled outward to cause deflection of the elongated segment 160 and disengage the knob 166 from the corresponding boss 168 . once the two latches 158 are disengaged , the unlocked backrest 141 can be removed from the seat portion 140 . referring to fig1 , the booster seat 106 can further include two anchoring latches 170 respectively operable to engage with the seat portion 110 of the seat frame 102 when the booster seat 106 is installed on the seat frame 102 . the two anchoring latches 170 can be respectively assembled with the two armrests 148 , and can respectively extend into the inner cavities 150 thereof . the two anchoring latches 170 can have a same construction , and can be respectively connected pivotally with the seat portion 140 of the booster seat 106 . in conjunction with fig1 , fig1 is an enlarged view illustrating the assembly of one latch 170 with one armrest 148 . the latch 170 can have an actuating portion 172 and a latching portion 174 . in one embodiment , the anchoring latch 170 including the actuating portion 172 and the latching portion 174 can be formed integrally as a single part . the actuating potion 172 can be exposed outward through the outer sidewall 148 b of the armrest 148 , and the latching portion 174 can protrude into the inner cavity 150 of the armrest 148 . moreover , a spring 176 can be respectively connected with the anchoring latch 170 and a fixed point of the seat portion 140 . the spring 176 can bias the anchoring latch 170 to a locking state for engagement of the latching portion 174 with the seat portion 110 of the seat frame 102 . as better shown in fig4 and 8 , the seat portion 110 of the seat frame 102 can have two slots 178 respectively formed on the left and right sides of the region 110 a above the beam 138 for receiving the locking engagement of the anchoring latches 170 . when the booster seat 106 is installed on the seat portion 110 of the seat frame 102 , the armrests 148 and the bend portion 153 of the seat portion 140 can respectively rest in contact with the beam 138 , and the region 110 a of the seat portion 110 can be received in the inner cavities 150 of the two armrests 148 and the inner cavity 153 a of the bend portion 153 . the booster seat 106 can be thereby supported at least partially by the beam 138 , and lateral and back and forth displacements of the booster seat 106 relative to the seat frame 102 can be prevented . moreover , the two anchoring latches 170 can respectively engage with the two slots 178 under the biasing action of the springs 176 to lock the booster seat 106 in place . for removing the booster seat 106 , the actuating portions 172 can be respectively depressed to disengage the anchoring latches 170 from the slots 178 . the unlocked booster seat 106 then can be removed from the seat frame 102 . as better shown in fig1 , the booster seat 106 can further include two storage drawers 179 for receiving at least partially a restraint harness ( not shown ) of the booster seat 106 . the storage drawers 179 can be assembled with the bottom portion 142 of the seat portion 140 . the restraint harness received in the storage drawers 179 may be deployed for attaching the booster seat 106 on an adult chair . in conjunction with fig1 , fig1 and 17 are schematic views illustrating the tray 108 . the tray 108 is detachably installable on the armrests 148 of the booster seat 106 over the seating surface 144 of the seat portion 140 . the tray 108 can include a rigid tray body 180 adapted for receiving items such as drinking bottles , bowls , dishes , etc . in one embodiment , the tray body 180 may be formed by the assembly of one or more casings , e . g ., an upper and a lower casing . the tray body 180 can define a front side 108 a , a rear side 108 b , a left and a right side 108 c and 108 d , and multiple corners 108 e ( e . g ., 4 corners 180 e ) of the tray 108 . the front and rear sides 108 a and 108 b respectively join with the left and right sides 108 c and 108 d at the corners 108 e . the rear side 108 b of the tray 108 is close to a child sitting on the booster seat 106 when the tray 108 is installed thereon . the tray body 180 can be assembled with two latches 182 ( better shown in fig1 ) for locking the tray 108 with the booster seat 106 . more specifically , an underside of the tray body 180 can have a cavity 181 delimited transversally between a left and a right sidewall 181 a , and the two latches 182 can be respectively disposed adjacent to the left and right sidewalls 181 a near the rear side 108 b of the tray 108 . in one embodiment , the latches 182 may be pivotally assembled with the tray body 180 . each latch 182 can have a plurality of teeth 182 a projecting into the cavity 181 , and an actuating portion 182 b that is affixed with the teeth 182 a and exposed at the underside of the tray 108 . in one embodiment , the latch 182 including the teeth 182 a and the actuating portion 182 b can be formed integrally as a single part . when the tray 108 is installed on the booster seat 106 , a top of the armrests 148 of the booster seat 106 can be respectively received in the cavity 181 respectively adjacent to the left and right sidewalls 181 a . the teeth 182 a of each latch 182 can engage with a locking slot 184 ( better shown in fig1 ) provided on the outer sidewall 148 b of the corresponding armrest 148 to lock the tray 108 with the booster seat 106 . the locking slot 184 can have a plurality of indentations for engagements of the teeth 182 a . each latch 182 can be respectively biased by a spring 186 ( shown with phantom lines in fig1 ) toward a locking state where the teeth 182 a engage with the locking slot 184 . moreover , each actuating portion 182 b may be independently operable to cause unlocking displacement of the corresponding latch 182 for disengaging the teeth 182 a from the locking slot 184 of the booster seat 106 . rather than the pivotal connection described above , another embodiment may have the latches 182 slidably assembled with the tray body 180 , which is schematically shown in fig2 . in this case , the latches 182 can respectively slide along a transversal direction ( i . e ., extending from the left side 108 c to the right side 108 d of the tray 108 ) to lock and unlock the tray 108 with respect to the booster seat 106 . to facilitate unlocking operation of the latches 182 , the tray 108 may further include a release member 187 that is coupled with the two latches 182 and can be operable to drive concurrent unlocking displacements of the two latches 182 . for example , the release member 187 can be slidably assembled with the tray body 180 at the front side 108 a , and can be respectively coupled with the two latches 182 via two linkage arms 188 . the two linkage arms 188 may be made of an elastically deformable material , and can be curved to respectively extend toward the left and right sides 108 c and 108 d of the tray 108 . each linkage arm 188 can have two ends respectively connected with a corresponding latch 182 and the release member 187 . when it is pulled outward , the release member 187 can drive sliding displacements of the linkage arms 188 , which in turn cause the latches 182 to move ( e . g ., rotation or sliding displacement ) for respectively disengaging from the armrests 148 of the booster seat 106 . as better shown in fig1 , the release member 187 can be further connected with a spring 189 . the spring 189 can bias the release member 187 toward the interior of the tray body 180 to an initial position corresponding to a locking state of the latches 182 . referring to fig1 and 17 , the tray 108 can further include a plurality of sockets 190 configured to receive the insertion of the leg extensions 104 . the sockets 190 can be affixed with the tray body 180 at locations respectively near the corners 180 e of the tray 108 . each socket 190 can include a pocket in which the connecting end 104 a of one leg extension 104 can be inserted for attachment . the pocket of the socket 190 can be formed in the tray body 180 , and opened at the underside of the tray body 180 . moreover , an inner sidewall of the pocket can include one or more ribs 191 . when one leg extension 104 is inserted into the socket 190 ( for clarity only one leg extension 104 is exemplary shown in fig1 with phantom lines ), the ribs 191 can respectively engage recesses 104 b provided on an outer surface of the connecting end 104 a of the leg extension 104 to assist in properly orienting the leg extension 104 and prevent its rotation in the socket 190 . it will be appreciated that alternate embodiments may place the ribs 191 on the leg extension 104 , and the recesses 104 b on the inner sidewall of the socket 190 . in conjunction with fig1 and 17 , fig1 is a schematic view illustrating further construction details of the tray 108 , and fig1 is an enlarged view of portion e shown in fig1 . referring to fig1 and 19 , each socket 190 can be respectively associated with a latch 192 operable to engage with the connecting end 104 a of the leg extension 104 for locking the leg extensions 104 with the tray 108 . the latches 192 can have a similar construction . each latch 192 can include a sleeve 192 a , a locking arm 192 b and a release button 192 c , which are all affixed together as a unitary part . in one embodiment , the latch 192 including the sleeve 192 a , locking arm 192 b and release button 192 c may be formed as an integral part . the sleeve 192 a , locking arm 192 b and release button 192 c can protrude from the sleeve 192 a in different directions . moreover , the latch 192 can be connected with a resilient member 193 , which is operable to bias the latch 192 toward a locking state . in one embodiment , the resilient member 193 may be formed integrally with the latch 192 , so that the latch 192 and the resilient member 193 may be provided as a single part . all of the latches 192 can be assembled with the tray body 180 in a same way . a post 194 affixed to the tray body 180 can be disposed through the sleeve 192 a to pivotally connect the latch 192 with the tray body 180 adjacent to one corresponding socket 190 . the post 194 can extend along a direction substantially perpendicular to a major support surface of the tray body 180 , so that the rotation axis of the latch 192 can be substantially perpendicular to the major support surface of the tray body 180 . an end of the locking arm 192 b can extend into the pocket of the socket 190 via a slot 196 formed through an inner sidewall of the socket 190 . the release button 192 c can be exposed outward through an opening of the tray body 180 for operation . the resilient member 193 can have a distal end anchored with a sidewall 198 affixed to the tray body 180 . when the connecting end 104 of the leg extension 104 is inserted in the socket 190 , the latch 192 can be rotationally biased by the resilient member 193 to a locking state in which the locking arm 192 b engages through the hole 137 on the connecting end 104 a of the leg extension 104 for locking the leg extension 104 with the tray 108 . the spring force applied by the resilient member 193 may cause a stop lip 195 ( better shown in fig1 ) provided at a side of the release button 192 c to abut against the tray body 180 at a border region of the opening where the release button 192 c is exposed , which can limit the course of the latch 192 and stop it in the locking state . moreover , the release button 192 c can be depressed to cause unlocking rotation of the latch 192 , which disengages the locking arm 192 b from the connecting end 104 a of the leg extension 104 . exemplary operation for converting the highchair assembly 100 to various configurations of use is described hereinafter with reference to fig1 - 20 . referring to fig1 - 3 , suppose that a caregiver wants to configure the highchair assembly 100 for seating a young child . the lower ends of the legs 120 and 122 of the seat frame 102 can be respectively inserted into the leg extensions 104 , and the resilient tongues 134 of the foot members 128 can be respectively engage with the holes 137 on the connecting ends 104 a of the leg extensions 104 for locking the leg extensions 104 with the seat frame 102 . the leg extensions 104 can thereby provide standing support for the highchair assembly 100 . moreover , the booster seat 106 can be installed on the seat frame 102 such that the lower edges 152 of the armrests 148 and the lower edge 154 of the bend portion 153 respectively rest in contact on the beam 138 , and the anchoring latches 170 can respectively engage with the slots 178 on the region 110 a of the seat portion 110 received in the inner cavities 150 of the two armrests 148 . the booster seat 106 can be thereby supported at by the beam 138 and securely locked with the seat frame 102 , the booster seat 106 lying above and substantially out of contact with the seating surface 114 of the seat frame 102 . for installing the tray 108 on the booster seat 106 , the tray 108 can be placed such that the top of the armrests 148 are received in the cavity 181 at the underside of the tray 108 , and the latches 182 of the tray 108 can respectively engage with the armrests 148 of the booster seat 106 to lock the tray 108 with the booster seat 106 . in case the tray 108 is unused , the latches 182 can be unlocked by respectively operating the two actuating portions 182 b at the left and right sides 108 c and 108 d of the tray 108 , or by pulling the release member 187 at the front side 108 a of the tray 108 . as a result , the two latches 182 can move for disengaging from the armrests 148 of the booster seat 106 , which can then be removed from the booster seat 106 . for converting the highchair assembly 100 from the configuration of fig1 to the configuration shown in fig4 , the actuating portions 172 at the left and right sides of the booster seat 106 can be respectively operated to disengage the anchoring latches 170 from the seat portion 110 of the seat frame 102 . the unlocked booster seat 106 then can be removed from the seat frame 102 , which converts the highchair assembly 100 to the configuration shown in fig4 . the booster seat 106 detached from the seat frame 102 may be used independently for seating a child on an adult chair as shown in fig5 and 6 . in this configuration , the storage drawers 179 may be opened so that the restraint harness ( not shown ) of the booster seat 106 can be pulled out and attached with the adult chair . for converting the highchair assembly 100 to a lower standalone chair configuration as shown in fig7 , the knobs 136 of the legs 120 and 122 can be depressed so as to disengage from the holes 137 of the leg extensions 104 , and the unlocked leg extensions 104 then can be removed from the legs 120 and 122 of the seat frame 102 . the seat frame 102 alone can thereby form an independent chair of a height smaller than that of the highchair assembly 100 . the standalone chair formed by the seat frame 102 can stand independently on the legs 120 and 122 , and can receive a child on the seating surface 114 . for converting the tray 108 to a standalone table configuration as shown in fig7 , the leg extensions 104 can be respectively inserted into the sockets 190 of the tray 108 , and the latches 192 can respectively engage with the holes 137 on the connecting ends 104 a of the leg extensions 104 to lock the leg extensions 104 with the tray 108 . the tray 108 can be thereby configured as a standalone table capable of standing independently on the leg extensions 104 . as shown in fig7 , the standalone table formed by the assembly of the tray 108 with the leg extensions 104 can be compatible for use with the standalone chair formed by the seat frame 102 , i . e ., the standalone table can be used by a child sitting on the standalone chair formed by the seat frame 102 . moreover , the standalone chair formed by the seat frame 102 may also be conveniently stowed under the tray 108 of the standalone table . advantages of the structures described herein include the ability to provide a highchair assembly that can be converted to different configurations according to the child &# 39 ; s age and needs . realizations of the highchair assembly have been described in the context of particular embodiments . these embodiments are meant to be illustrative and not limiting . many variations , modifications , additions , and improvements are possible . these and other variations , modifications , additions , and improvements may fall within the scope of the inventions as defined in the claims that follow .
a convertible highchair assembly includes a seat frame , a booster seat detachably installable on the seat frame , a tray detachably mountable on the booster seat and having a plurality of sockets , and a plurality of leg extensions selectively attachable to any of the support frame portion and the tray , each of the leg extensions having a connecting end . the seat frame includes a support frame portion and a seat portion affixed with each other , the seat portion being adapted to receive a child . the connecting ends of the leg extensions are attached to the support frame portion for configuring a highchair , and the connecting ends of the leg extensions are respectively inserted into the sockets while the tray is removed from the booster seat for configuring a standalone table , the leg extensions providing standing support for the tray .