Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C1/00—Chairs adapted for special purposes
  • A47C1/02—Reclining or easy chairs
  • A47C1/031—Reclining or easy chairs having coupled concurrently adjustable supporting parts
  • A47C1/032—Reclining or easy chairs having coupled concurrently adjustable supporting parts the parts being movably-coupled seat and back-rest
  • A47C1/03255—Reclining or easy chairs having coupled concurrently adjustable supporting parts the parts being movably-coupled seat and back-rest with a central column, e.g. rocking office chairs
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C1/00—Chairs adapted for special purposes
  • A47C1/02—Reclining or easy chairs
  • A47C1/022—Reclining or easy chairs having independently-adjustable supporting parts
  • A47C1/024—Reclining or easy chairs having independently-adjustable supporting parts the parts, being the back-rest, or the back-rest and seat unit, having adjustable and lockable inclination
  • A47C1/026—Reclining or easy chairs having independently-adjustable supporting parts the parts, being the back-rest, or the back-rest and seat unit, having adjustable and lockable inclination by means of peg-and-notch or pawl-and-ratchet mechanism

Definitions

• the present invention relates to a locking device for office chairs and the like.
• office chairs generally present adjustable parts in height and tilt. These chairs might present the back, and sometimes also the seat or the frame, adjustable in tilt in respect to a base unit, for example of a box form, which is connected at the top end of an upright which defines ⁇ the vertical support of the chair.
• the connection between the base unit and the upright is realized substantially through a frustum of cone element united 'to a base ' unit and fit to receive the top end of the upright.
• the locking element is mobile at least between a front resting position which cooperates with the slots and a back resting position in which the swing is permitted.
• Such locking element is usually operatively associated to the back, but can be also associated to the seat, and in particular, in the asynchronous mechanism, a locking -element for the back and one for the seat could be envisaged.
• the known technique, briefly described above, presents some drawbacks.
• the known locking devices in fact generally allow the association for each tilt position, of a single locking element in a corresponding seat. This makes it necessary to realize the locking element and the unit which includes the slots in sufficiently resistant material, in order to avoid the risk of a structural failure of the same.
• Such locking devices can often also become rather cumbersome, and to guarantee the reciprocal receding and advancing of the locking elements and of the slots it is sometimes necessary to opportunely modify the structure of the swinging mechanism with a consequent bigger complica- tion. It has also to be noted that, as in the mechanisms there is a frontal advancing and receding of the locking elements, the force resulting from the contact between such elements has a tangential component which can show a tendency to pull back the locking elements, and can therefore cause the accidental unlocking of the device. Such problematic issues require the necessity of very accurate designing of the locking device, with consequent higher costs of designing and realization of the said device.
• the technical task set at the base of the present invention is to invent a locking device for office chairs and the like to be in a good enough position to obviate substantially the problems mentioned.
• - fig. 1 shows a prospective view of a locking device for office chairs according to the present invention
• - fig. 2 is a section on a lateral view of a tilting mechanism for an office chair including the locking device of figure 1;
• - fig. 3 is part of a section of the device of figure 1, in an active operative position of locking, executed according to a horizontal plan,--
• FIG. 4 is an view analogous to that of figure 3 with the locking device in a passive operative position of locking;
• - fig. 5 shows an alternative profile for a locking element
• a locking device for office chairs and the like is globally shown with reference No 1.
• the locking device 1 is advantageously applicable to a mechanism 2 for an office chair, which includes essentially a base unit 3 fit to engage, through a connecting element 4, to the top end of an upright 5 which defines the vertical support of the chair.
• On the base unit 3 at least a revolving portion 6 of the chair is hinged in a known way, for example an supporting element 7 of the back.
• the mechanism 2 includes also an supporting element 8 of a seat of a chair, mounted above the base unit 3.
• the device 1 is applicable in a manner similar to all the types of known mechanisms, and therefore to mechanisms at "permanent contact” , in which the supporting element of the seat is joined to the base unit and the only reclining part is the back, to mechanisms of "synchronous" type, in which the supporting element of the seat is associated in a revolving way to the base unit and to the supporting element of the back to swing proportionally to the swinging of the supporting element of the back and to mechanisms of "swinging" type, in which the element of support of the seat is fixed to the supporting element of the back to swing jointly with the same.
• the locking device can also be used in mechanisms of "asynchronous" type, in which the supporting element of the seat is associated in a revolving way to the base unit, to swing in an independent way in respect to the base unit .
• the mechanism includes a second locking device operatively placed between the supporting element of the seat and the base unit .
• Means of elastic support are usually also foreseen (not shown on the figures) , such as a spring, placed between each turning portion in an independent way and the base unit, and therefore at least between the supporting element and base unit.
• the locking device 1 includes a first locking element 9 having a first portion of engagement 9a mounted on the base unit 3, and a second locking element 10 having a second portion of engagement 10a and mounted on the rotating portion 6.
• the first engagement portion 9a and the second engagement portion 10a are selectively associable , in an active position to lock the rotation of the revolving portion 6 in respect to the base unit 3 and can dissociate in a passive position to unlock such rotation.
• a contrasting force develops between the two engaging portions 9a , 10a and therefore between the two locking elements 9,10, due to the action created on the mobile portion by the means of elastic support, when the chair is not in use, and by the weight of the user when the chair is used.
• Such force which has a tangential component to the contact's surfaces of the engaging portions 9a, 10a and a perpendicular component to such surfaces, is due to the rotary action acting in direction 12, on the second element 10, and is inclined to push back the first locking element 9 away from the second locking element 10.
• the contrasting force therefore lies in the plane in which has been executed the section of figure 2.
• the displacement between the active and the passive positions occurs along a displacement's direction substantially perpendicular to the contrasting force.
• such displacement besides is substantially perpendicular also to the tangential components and perpendicular to the contact surfaces between the engaging portions 9a, 10a.
• the displacement happens perpendicularly to the force which tends to distance the two locking elements 9, 10 and therefore such force cannot separate such elements 9, 10.
• the direction of the displacement is shown in figure 1 with the reference number 11.
• the displacement could be a lateral displacement relative to the first 9a and to the second 10a portion of engagement.
• lateral displacement it is understood a displacement in a transversal direction and preferably perpendicular to a vertical plane passing centrally on both the first 9 and on the second locking element 10, when these are in active position.
• the displacement substantially happens perpendicularly to the direction of the frontal distancing between the engaging portions 9a, 10a.
• the first 9a and second 10a engaging portions are reciprocally faced in correspondence to a contact surface.
• the displacement between the active position and the passive position takes place along a direction of displacement and shift parallel to the surface of contact.
• the displacement between the active position and passive position takes place along a direction of movement substantially parallel to the rotating axis 13 of the revolving portion 6.
• the first locking element 9 is translational in a lat- eral and parallel way to the surface of the engaging portion 9a to lock selectively the rotation of the revolving portion 6, while the second locking element 10 is fixed to the revolving portion 6.
• the first locking element 9 consists preferably of a portion of a circular crown entirely toothed and cooperating with the second engaging portion 10a.
• the teeth are all cooperating contemporarily with the second engaging portion 10a in the operative active position.
• the second locking element 10 is a wheel, at least partially toothed (figure 1) and therefore provided with a number of resting positions, in which the teeth can be inserted.
• the wheel is fixed to the revolving portion 6 to rotate jointly with it, according to the direction shown of figures 1 and 2 with number 12, around the axis 13.
• the first 9 and second 10 locking elements could be provided with corresponding set of teeth having an involute, square and other type profile.
• FIG 5 is shown an example of a profile for an undercut toothed gear placed on the second element 10 but applicable in an analogue way and counter-shaped on the first element 9, which offers a further advantage to impede a frontal detachment of the locking elements, not requiring the pres-- ence of a containing element 21 for the first locking element .
• the first locking element 9 is provided with stopping elements, for example studs, on a lateral face, extending therefore in the shifting direction 11 of the same first element.
• the second element 10 is provided with proper stopping seats, such as shaped holes or the like, also these extending in the shifting direction 11 of the first locking element 9 to cooperate with the stopping elements of the first locking element 9.
• the device 1 includes also operating means 14 operatively connected to the first locking element 9 to execute the locking and unlocking of the device 1.
• the operating means 14 include a push rod 15 assembled in a revolving way on the base unit 3 and manually actionable, for example through a lever (not illustrated) , on which is assembled the first locking element 9 in a translational way.
• the operating means 14 comprise also cam shaped means 16 operatively associated to the push rod 15 to convert the rotary movement of the push rod 15 in a translational movement of -li ⁇
• the cam shaped means 16 include a small pivot 17 integral with and transversal to the push rod 15 and an operating element 18 freely and glidingly associated to the rod and provided with a cam track 19 in which the small pivot 17 is inserted.
• the cam track 19 is provided with a transferring central portion 19a and of two end portions 19b, 19c, corresponding to the active and passive positions, which are slanted in respect to the transferring central portion 19a in order to prevent the accidental slip of the operating element 18 when the locking is in an active and passive position.
• the operating means 14 include also an elastic element 20 connecting operatively the first locking element 9 and the second command element 18, to guarantee the functions of pre-selection and anti-shock of the locking.
• the device 1 includes two first locking elements 9, 9' and two second locking elements 10, 10' assembled on the push rod 15. Such elements are symmetrically positioned on opposite sides of the revolving portion 6 to avoid loss of balance of the revolving portion 6 in locking position and are respectively cooperating to block the rotation of the revolving portion 6.
• the mechanism 2 includes a device to adjust the height of the chair, which is itself not described as it is a known type.
• the locking device 1 described above could therefore be applied to any chair having reclining portions, which is usually provided with a back, fixed to the supporting . element 7 of the back, of a seat, fixed to an supporting element 8 of the seat, of a vertical upright resting on a base, and eventually of arms for the support of the upper body of the user .
• the functioning of a locking device, above described in a prevalently structural sense, is the following.
• the revolving portion can oscillate constrained by the means of elastic support.
• the small -pivot 17 runs inside the cam track 19 of the operating element 18, making the same move along the push rod 15 towards the first locking element 9.
• the elastic element 20 is therefore compressed and pushes the first locking element 9 towards the second locking element 10. If the second locking element 10 is situated with the resting seats in line with the teeth of the first locking element 9, the device 1 goes immediately into active position (figure 3) . If that is not the case, ' the device finds itself in pre-selection, and as soon as the revolving portion 6 is rotated in a proper angular position, the first locking element 9 is pushed together with the second locking element 10 and activates the locking.
• a locking device according to the present invention offers a good deal of freedom in designing the locking device and of the relative positioning. Besides such device assures a secure locking of the swinging with the result of being particularly compact. Besides it has to be underlined that the locking device for office chairs results in a simple and fast realization.
• a device according to the present invention presents reduced costs of production and allows also to use materials of relatively little resistance for the locking elements.

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• Health & Medical Sciences (AREA)
• Dentistry (AREA)
• General Health & Medical Sciences (AREA)
• Chairs For Special Purposes, Such As Reclining Chairs (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=32894147

Family Applications (1)

Country Status (7)

Families Citing this family (6)

Citations (6)

Family Cites Families (6)

• 2003
  • 2003-02-21 IT IT000016A patent/ITBS20030016A1/it unknown
• 2004
  • 2004-02-16 DE DE602004004372T patent/DE602004004372T2/de not_active Expired - Fee Related
  • 2004-02-16 CA CA002516778A patent/CA2516778A1/en not_active Abandoned
  • 2004-02-16 EP EP04711436A patent/EP1596690B1/de not_active Expired - Lifetime
  • 2004-02-16 WO PCT/IT2004/000062 patent/WO2004073455A1/en active IP Right Grant
  • 2004-02-16 CN CNA2004800047093A patent/CN1750776A/zh active Pending
  • 2004-02-16 US US10/545,577 patent/US20060290185A1/en not_active Abandoned

Patent Citations (6)

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