Illumination – Supports – Ceiling-suspended support
Patent
1997-09-15
1999-10-26
O'Shea, Sandra
Illumination
Supports
Ceiling-suspended support
362804, 362 33, 362402, F21S 104
Patent
active
059715723
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a device for angularly positioning a mass relative to a horizontal support axis, and in particular to a device for positioning a light of a light apparatus for operating rooms.
It also relates to lighting apparatus provided with such a device.
DESCRIPTION OF THE RELATED ART
There are known devices for angularly positioning a mass relative to a horizontal support axis, of the type comprising a support arm adapted to carry said mass and mounted angularly displaceably about said support axis, and a balancing member for said arm connected to the latter and coacting with a resilient return member adapted to apply to a point on the support arm a balancing moment for the mass opposing the moment engendered by the weight of the latter.
In lighting apparatus provided with such devices, the balancing member is constituted by a chain connected by one of its ends to the support arm and by its other end to the resilient return member.
The resilient return member is constituted by a fixed spring whose general axis is disposed perpendicular to the support axis.
The device is moreover provided with an angular return constituted by a roller on which the chain bears, such that the force exerted by the latter on the spring will be parallel to the longitudinal axis of the spring no matter what the position of the support arm.
Because of their construction, devices of this type do not permit stable angular positioning of the light about its horizontal support axis over a range of 360.degree..
Thus, when the chain bearing against the roller forms an angle less than about 160.degree., the friction between the chain links and the roller increases, which tends to unbalance the support arm.
Moreover, the limit position for the light is reached when the chain forms an angle of 180.degree., that is, is rectilinear. Thus, beyond this position, the chain is no longer in contact with the roller and thereafter exerts a force in an angular direction offset from the longitudinal axis of the spring, which also tends to make the balancing less effective.
Devices of this type also cause irregular displacement of the support arm about its support axis due to the irregular displacement of the chain against the roller.
SUMMARY OF THE INVENTION
The invention seeks to overcome these drawbacks by providing a device for angular positioning of a mass relative to a horizontal support axis, permitting regular angular displacement of the mass as well as balancing of this latter no matter what its angular position.
It therefore has for its object a device for angular positioning of a mass relative to a horizontal support axis of the mentioned type, characterized in that the assembly constituted by the balancing member and the resilient return member is mounted oscillably about an axis of oscillation, parallel to the support axis and located at a fixed distance from the latter, so as to permanently orient itself toward said point during angular displacements of the support arm.
The invention may also comprise one or several of the following characteristics: a housing mounted oscillably on said oscillation axis and provided with a bottom delimiting a bearing surface for an end region of the spring, whose opposite end region coacts with the balancing member of the support arm; provided in the bottom of the housing and axially displaceable in the latter under the control of the support arm; member is disposed in a frame, said oscillation axis being defined by two lugs engaging in two respective bearings, provided one in the external wall of the housing and the other in the internal wall of the frame; eccentric crank pin on which is articulated the balancing member; direction substantially perpendicular to the support arm so as to exert on the latter, under the influence of the balancing member, a maximum balancing moment when the support arm is in a horizontal position and a minimum balancing moment when the support arm is in a vertical position; the crank pin being secured to a support memb
REFERENCES:
patent: 5025359 (1991-06-01), Saluja
Rouchon Jean-Jacques
Verdier Alain
ALM
Honeyman Marshall
O'shea Sandra
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