Chair control

Claim 2

A tilt assembly for a chair, said assembly comprising: a control housing; a back support lever pivoted to said control housing; a torsion spring disposed within said control housing, said torsion spring having first and second ends, said first end engaging said back support lever; an adjuster plate having a forward end pivoted to said control housing, said adjuster plate further having a rearward end; an adjuster nut engaging the rearward end of said adjuster plate, said second end of said torsion spring engaging said adjuster plate; and an adjuster screw mounted on said control housing and engaging said adjuster nut.

Claim 3

A tilt assembly as defined by claim 1 wherein said adjuster plate rearward end has a forked configuration in plan.

Claim 4

A tilt assembly as defined by claim 2 wherein said adjuster nut includes an enlarged center section which defines a threaded bore which engages said adjuster screw.

Claim 5

A tilt assembly as defined by claim 3 wherein said adjuster nut further includes outwardly extending pins joined to said enlarged center section.

Claim 6

A tilt assembly as defined by claim 4 wherein said plate rearward end defines grooves for receipt of said outwardly extending pins.

Claim 7

A tilt assembly as defined by claim 5 wherein said torsion spring has an axis offset from and parallel to the pivot axis of said back support lever.

Claim 8

A tilt assembly as defined by claim 1 wherein said adjuster nut includes an enlarged center section which defines a threaded bore which engages said adjuster screw.

Claim 9

A tilt assembly as defined by claim 1 wherein said adjuster nut includes outwardly extending pins engaging said adjuster plate.

Claim 10

A tilt assembly as defined by claim 1 wherein said adjuster nut includes an enlarged center section and outwardly extending pins joined to said center section.

Claim 11

A chair control comprising: a control housing; a pair of coaxially aligned coil springs disposed within said housing and defining a coiling axis; back support levers pivoted to said control housing at locations spaced from the coiling axis for movement about a pivot axis offset located generally forwardly and parallel to the coiling axis of said coil springs, each of said coil springs having an end engaging one of said back support levers; an adjustment bolt on said housing; an adjustment nut having a threaded bore engaging said adjustment bolt and a pair of outwardly extending portions positioned to overlie ends of said coil springs whereby rotation of the adjustment bolt moves said adjustment nut and adjusts the tension of said springs; and an adjustment plate having an end pivoted to said control housing and another end engaged by said adjustment nut.

Claim 12

A chair control comprising: a control housing; a pair of coaxially aligned coil springs disposed within said housing and defining a coiling axis; back support levers pivoted to said control housing at locations spaced from the coiling axis for movement about a pivot axis offset located generally forwardly and parallel to the coiling axis of said coil springs, each of said coil springs having an end engaging one of said back support levers; an adjustment bolt on said housing; an adjustment nut having a threaded bore engaging said adjustment bolt and a pair of outwardly extending portions positioned to overlie ends of said coil springs whereby rotation of the adjustment bolt moves said adjustment nut and adjusts the tension of said springs; and an adjustment plate having an end pivoted to said control housing and another end engaged by said adjustment nut.

Claim 13

A chair control as defined by claim 7 further including an adjustment knob connected to said bolt externally of said housing.

Claim 14

A support mechanism for a chair comprising: a frame having two opposing generally vertical sides; lever means pivotally attached to said vertical sides at a first position so that said lever means rocks about said first position relative to said frame; torsional spring means for applying an upward force to said lever means and having a generally horizontal longitudinal axis at a second position rearward of said first position; torsion adjusting means for adjusting the upward force provided by said spring means, said spring means comprising a first portion braced against said lever means at a third position rearward of said second position and a second portion braced against said torsion adjusting means forward of said first position, whereby said spring means provides an adjustable upward force to said lever means at said third position, said torsion adjusting means including an adjuster plate having a forward end pivoted to said frame and having a rearward end, said torsion adjusting means further including an adjuster nut supported on the rearward end of said adjuster plate and an adjuster screw mounted on said frame and operably engaging said adjuster nut.

Claim 15

A support mechanism for a chair comprising: a frame having two opposing generally vertical sides; lever means pivotally attached to said vertical sides at a first position so that said lever means rocks about said first position relative to said frame; torsional spring means for applying an upward force to said lever means and having a generally horizontal longitudinal axis at a second position rearward of said first position; torsion adjusting means for adjusting the upward force provided by said spring means, said spring means comprising a first portion braced against said lever means at a third position rearward of said second position and a second portion braced against said torsion adjusting means forward of said first position, whereby said spring means provides an adjustable upward force to said lever means at said third position, said torsion adjusting means including an adjuster plate having a forward end pivoted to said frame and having a rearward end, said torsion adjusting means further including an adjuster nut supported on the rearward end of said adjuster plate and an adjuster screw mounted on said frame and operably engaging said adjuster nut.

Claim 16

A support mechanism as defined in claim 10 wherein said torsional spring means includes a coil spring.

Claim 17

A support mechanism as define in claim 11 wherein said torsional spring means includes a second coil spring generally aligned with said first-mentioned coil spring.

Claim 18

A support mechanism as defined in claim 10 wherein said frame includes a control housing.

Claim 19

A chair control comprising: a housing; a lever pivotally supported by said housing at a pivot defining a back tilt axis, said lever being configured to support a chair back; a torsion spring operably supported in said housing for applying an upward force to said lever, said torsion spring defining a coiling axis about which said torsion spring winds and unwinds, said coiling axis being located rearward of said back tilt axis, said torsion spring further including first and second torque arms; and an adjustment mechanism supported on said housing for adjusting the tension of said torsion spring, said first torque arm being braced against said lever in a first position rearward of said back tilt axis and said second torque arm being braced against said adjustment mechanism, said adjustment mechanism including an adjuster plate having a forward end pivoted to said housing and having a rearward end, said adjustment mechanism further including an adjuster nut supported on the rearward end of said adjuster plate and an adjustment bolt mounted on said housing and operably engaging said adjuster nut.

Claim 20

A chair control comprising: a housing; a lever pivotally supported by said housing at a pivot defining a back tilt axis, said lever being configured to support a chair back; a torsion spring operably supported in said housing for applying an upward force to said lever, said torsion spring defining a coiling axis about which said torsion spring winds and unwinds, said coiling axis being located rearward of said back tilt axis, said torsion spring further including first and second torque arms; and an adjustment mechanism supported on said housing for adjusting the tension of said torsion spring, said first torque arm being braced against said lever in a first position rearward of said back tilt axis and said second torque arm being braced against said adjustment mechanism, said adjustment mechanism including an adjuster plate having a forward end pivoted to said housing and having a rearward end, said adjustment mechanism further including an adjuster nut supported on the rearward end of said adjuster plate and an adjustment bolt mounted on said housing and operably engaging said adjuster nut.

Claim 21

A chair control as defined in claim 15 wherein said torsion spring includes a coil spring.

Claim 22

A chair control as defined in claim 17 wherein said torsion spring includes a second coil spring generally aligned with said first-mentioned coil spring.

Claim 23

A chair control as defined in claim 15 wherein said second torque arm is braced against said adjustment mechanism forward of said coiling axis.