Closure fasteners – Extension link – Multiple
Patent
1993-12-07
1996-07-30
Lindsey, Rodney M.
Closure fasteners
Extension link
Multiple
292DIG12, 49339, E05C 1732
Patent
active
055404669
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a mechanism for latching a rotary shaft, which mechanism is provided with a control arm, which at its one end is immovably connected to the rotary shaft and at its other end is coupled by a pivotal shaft to the end of a coupling piece, the other end of which is connected by means of a pivotal shaft to one end of an operating arm, which is rotatable about a pivotal shaft mounted immovably relative to the rotary shaft, the pivotal shaft between the coupling piece and the operating arm running parallel to both the pivotal shaft between the control arm and the coupling piece and the pivotal shaft mounted immovably relative to the rotary shaft, and being movable both into and out of the plane determined by both last-mentioned pivotal shafts, for latching or rotating the rotary shaft.
Such a mechanism is known from U.S. Pat. No. 4,202,572. In this case the control arm bears the bolt of a lock for an escape door, so that in normal circumstances the mechanism will always be in the latched position. If the escape door has to be used, the mechanism can be operated by a control unit in the form of a push-button, which on displacement acts upon the coupling piece and in so doing unlatches the mechanism, with the result that the bolt releases and the escape door can be pushed open by hand. The escape door will then swing into the open position in quite an uncontrolled manner.
SUMMARY OF THE INVENTION
The object of the invention is to improve such a mechanism in such a way that a controlled opening and closing of a door can be achieved therewith, in such a way that it is suitable for operating a swing lift door, which means that, on the one hand, a reliable latched position must be ensured and, on the other, a blocking of the swing movement of the lift door must not lead to unacceptable forces on the person or object causing the blocking, or on the mechanism itself.
This is achieved according to the invention by a mechanism of the type described in the preamble, in which the operating arm bears a further shaft at a distance from the immovably mounted shaft, upon which shaft an element of the control mechanism acts pivotally, and the control mechanism can be actuated by a control unit which in a first control position exerts a positive force on the control mechanism, which force can rotate the rotary shaft out of its latched position into a second position while at the same time tensioning spring means belonging to the control mechanism, which spring means on blocking of a rotation of the rotary shaft, and thus of the operating arm, are additionally tensioned through absorbing the force exerted by the control unit when the operating arm is at a standstill, which additional tension on removal of the blocking still moves the rotary shaft into the second position, and where in a second control position the control unit essentially releases the control mechanism, with the result that the spring means tensioned earlier can cause the rotary shaft to rotate out of the second position into the latched position.
Through these measures, a suitable actuation of the control unit means that a reliable latched position is automatically obtained through the operating arm and the coupling piece moving into line with each other. Further turning of the control arm is not possible, due to the fact that the operating arm and the control arm are lying in line with each other; turning back is prevented, due to the fact that a force exerted by the control arm exerts only a pressure force, but no moment, on the assembly of operating arm and coupling piece lying in its dead centre position. It goes without saying that said assembly can also lie slightly past the dead centre position.
Moving out of the latched position is effected by a displacement carried out by the control unit, by means of which a force is exerted on the control mechanism, which during normal operation will thus cause the rotary shaft to rotate and will make a lift door fixed thereto swing open, while at the same time en
REFERENCES:
patent: 1721967 (1929-07-01), Mohr
patent: 4202572 (1980-05-01), Green
patent: 4848175 (1989-07-01), Weiss
Lindsey Rodney M.
Thyssen De Reus B.V.
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