Note: Descriptions are shown in the official language in which they were submitted.
CA 02264645 1999-02-26DescriptionThe invention concerns a restraint to prevent recoil of a spring-loaded furniture part with thefeatures of the principal clause of Claim 1.This type of restraint to prevent recoil of a first springâloaded furniture part, in which thisfirst fumiture part is mounted to pivot on a second furniture part and the angle of inclination betweenTranslated by:TCAâTrans|ation Co. of America10 West 37th StreetNew York, N.Y. 10018 (212) 563.7054CA 02264645 1999-02-26TCA Translation TCA Translationthe two fumiture pzuts czm be set by clamping a threaded spindle, which is ï¬xed to one furniture part andmounted free of selfârestraint in a nut part on the other fumiture part, in which the threaded spindle orthe nut part is a rotatable part and these functional parts are arranged in a housing on one furniture part,is known from German Patent Application No. 197 20 264.The task of the present invention is to devise an improved restraint with greater functionalreliability.This task is solved with the features mentioned in the characterizing part of Claim 1.Modifications and advantageous variants of the invention are contained in the additional claims.A restraint of the type mentioned at the outset is characterized according to the invention by thefact that clamping of the threaded spindle occurs by exerting a force on the clamping jaws acting on it viaan operating mechanism, in which the operating mechanism is mounted in or on the housing, that therotatable part has at least pzutially em outer gear rim or locking hooks with which a locking part mountedto move on the housing and having a matching stop can be engaged, that the operating mechanism is connectedto a lock release device, in which during assumption of the clamping position of the operating mechanismthe lock release device brings the locking part with the gear rim or locking hooks into blockingengagement, and that means are provided to keep the locking part engaged with the gear rim or locking hookafter the clamping force acting on the clamping jaws is released and this engagement is released bychanging the angle of inclination between the two furniture parts.A preferred variant of tlie invention also has one or more of the features that the furniture partsare the seat and back rest of a chair, like an office swivel chair, and that the housing is a seat supportrigidly connected to the seat, that the threaded spindle is guided on one end to run free of self-restraintin a nut part of the back rest support and the clamping jaws, the operating mechanism, the lock releasedevice, the locking part and the gear rim or locking hooks are arranged on the other end of the threadedspindle in the seat support, that the operating mechanism is a clamping spindle guided transversely to thethreaded spindle through the seat support and the clamping jaws arranged in it, which is connected to anoperating lever mounted outside of the support on it, by means of which a force directed transversely tothe axis of the threaded spindle can be applied to the clamping jaws and clamp them to the threaded spindle,that the locking part is a lever mounted to swivel on one end arranged transversely to the gear rim orlocking hooks laterally from them in the seat support, in which spring devices are present on its other endATranslated by:TCA-Translation Co. of America10 West 37th StreetNew York. N.Y. 10018 (212) 563-7054CA 02264645 1999-02-26TCA Translation TCA Translationto keep this in a nonâlocking position and the lock release device introduces a clamping part thatovercomes this spring force between the lever and a stop part rigidly connected to the seat support, thatthe clamping part is a projection of a clamping lever, which is mounted with one end on the stop part andwhose axis of rotation is arranged perpendicular to the axes of the threaded spindle and the clampingspindle, in which the clamping lever is connected on its other end to the lock release device and can bebrought by this into a clamping position, that the lock release device is a rod guided with limited movementon one end in the operating lever, which is arranged essentially transverse to the axis of the threadedspindle and on its other end has a hook for connection to the clamping lever, in which the motion limitationon the rod is designed so that this pulls the clamping lever into a clamping position during clampingactivation of the operating lever and/or that a compression spring is arranged under tension around thethreaded spindle between the nut part arranged on the bottom end of the back rest support and the seatsupport, to force these to push apart and to impart a specific direction of rotation to the threadedspindle, that the locking part with the gear rim or locking hooks are brought into blocking engagement inthis direction of rotation of the threaded spindle, and that a movement of the threaded spindle oppositethis direction of rotation releases blocking.The invention is further described below with reference to drawings as examples. In the drawings:Figure l shows a partial section through a restraint with a threaded spindle in the clampedposition;Figure 2 shows the restraint of Figure l in the free position;Figure 3 shows a top view ofthe restraint in the position of Figure 1;Figure 4 shows a top view of the restraint in the position of Figure 2.The restraint of Figures 1 â 4 is mounted in a housing 1, which is arranged on the bottom of a seatsupport 2 with a U-shaped cross section and encloses a threaded spindle 3, 3', which is mounted on one endto run free of self-restraint in a nut part (not shown) arranged on a back rest support of an office chairand is mounted to rotate on its other end but is ï¬xed in housing 1. Because of mounting of one end ofthreaded spindle 3, 3' free of selfârestraint in the nut part a length change between the back rest supportand the seat support 2 is possible, which results in a change in angle of inclination between the seat andback rest of the office chair. A compression spring 17 is arranged under tension between the seat support2 and the nut part on the back rest support connected to swivel on the end of the seat support, which actsTranslated by:TCA-Translation Co. of America10 West 37th StreetNew York, N.Y. 10018 (212) 553.7054CA 02264645 1999-02-26TCA Translation TCA Translation on an end of the back rest support situated beneath the connection. A clamping device for threaded spindle3, 3' is arranged in front of housing 1 in the seat support 2, which consists of two clamping jaws 16, 16',which are mounted on a clamping spindle 18 n10Lll)lC(l in the side wall 2' of seat support 2 and arrangedtransverse to the threaded spindle 3, 3'. A compression spring 1â) acts between clamping jaws 16, 16', whichis to facilitate their loosening from the threaded spindle. The clamping spindle 18 lies on its other endwith a nut 20 behind the farther removed clamping jaw 16', in which this is clamped onto the threadedspindle 3' by the pressure of the nut. The clamping pressure is caused by a tensile force on the clampingspindle 18, which is applied in known fashion by an operating lever 14, in which this is forced through aneccentric surface 15 on the outer surface ofwall 2' of seat support 2 and secured. If clamping of threadedspindle 3' is released by operating the operating lever 14, the compression spring 17 would allow the backrest to spring forward on the top. To prevent this the restraint according to the invention is arrangedin housing 1.The restraint consists of a locking part, which is designed as a lever 5 or detent pawl amd has anotch that can be engaged with a gear rim 4 arranged around threaded spindle 3 and connected to rotate inunison with it, as shown in Figure l. The lever 5 is arranged here laterally chamfered transversely to theaxis of threaded spindle 3'. The lever is forced downward on its side facing the operating lever 14 by aspring 8 arrangusing top 1'. The teeth 4' of the gear rim are chamfered in the clockwise direction andengage in the matching notches 6 of lever 5, in which the threading of threaded spindle 3' is designed sothat the pressure of compression spring 17 ensures rigid wedging in this position between lever 5 and gearrim 4. Movement of the nut part on the other end of threaded spindle 3' causes rotation of the gear rimcotuiterclockwise so that the lever 5 can be released from the gear rim and reaches a position as shown inFigure 2 under the inlluence of a compression spring 7, which acts between the housing bottom 1 and the endof lever 5 facing away from operating lever 14. The end of lever 5 facing operating lever 14 has a downwarddirected chamfering 5' and then a stop end 5â in which, on loosening of lever 5, this slides with chamfcring5' over the side edge of housing bottom 1 , This arrangement achieves a situation in which the back rest canbe loosened only in a movement opposite the direction in which it was advanced.The blocking position of the restraint is achieved by operating operating lever 14. A rod 1 1 isarranged in this parallel to clamping spindle 18, which is guided over the housing 1 of the restraint. Therod 1 1 is guided with restricted movement by the stop device in a hole of the operating lever 18 and is4Translated by:TCAâTransIation Co. of America10 West 37th StreetNew York, N.Y. 10018 (212) 563.7054CA 02264645 1999-02-26....u.-..TCA Translation TCA Translationpulled outward over a specified path by pivoting the operating lever 18 in the clamping position for theclamping jaw 16, 16'. On its other end the rod 1 l is provided with a downward directed hook 12, whichengages in the free end of a clamping lever 9 mounted to pivot on housing 1, which is aligned in the clampingposition parallel to the threaded spindle 3, 3' and is arranged laterally on the housing with an axis ofrotation perpendicular to the threaded spindle. In the released position the clamping lever 9, as shownin Figure 4, protrudes obliquely from housing 1. If the rod l l is pulled by operating the operating lever14, the clamping lever 9 pivots into the position ough an inward directed protrusion 10 it then presses onthe end of lever 5 facing away from operating lever 14 and moves this to the right and downward against theforce ofcompression spring 7, as is apparent on comparison of Figure 2 with Figure 1. The teeth 4' of thegear rim 4 of threaded spindle 3' then engage in the notches 6 of lever 5 and the threaded spindle, asdescribed above, is blocked by the force of compression spring 17.SummaryRestraint to prevent recoil ofa springâloaded first furniture part, in which this first furniturepart is mounted to pivot on a second f umiture part and the angle of inclination between the two furnitureparts can be adjusted by clamping a threaded spindle, which is mounted ï¬xed on one ftuniture part and freeof self-restraint on a nut part on the other furniture part, in which the threaded spindle or the nut partis a rotatable part and these functional parts are arranged in a housing on a furniture part in whichclamping of the threaded spindle occurs by exerting a force on the clamping jaws acting on these via anoperating mechanism, in which the operating mechanism is mounted in or on the housing, in which therotatable part has at least partially an outer gear rim or locking hooks with which a locking part mountedto move on the housing and having a matching step can be engaged, in which the operating mechanism is alsoconnected with a lock release device, in which, on assumption of the clamping position of the operatingmechanism, the lock release device brings the lock part into blocking engagement with the gear rim orlocking hooks and in which, finally, means are provided to keep the locking part engaged with the gear rimor locking books after the clamping force acting on the clzunping jaws is removed and this engagement isreleased by changing the angle of inclination between the two furniture parts.Translated by:TCAâTransIation Co. of America10 West 37th StreetNew York, N.Y. 10018 (212) 563-7054
