Mechanism assisting the opening of a flap closure in building constructions

The subject of the invention is an assisting mechanism for opening a flap closure of openings in building constructions, especially of hatches and roof windows of the tilting or turning type.

Flap closures in building constructions consist of a frame and a flap (sash or cover), connected by hinges. When the axis of rotation of the flap lies in a non- vertical plane, then its opening requires application of a considerable force by the user, compensating the weight of the flap (sash or cover). In order to assist opening, such closures are fitted with a spring device, usually of a telescopic system, installed between the flap and the frame so that the action of the spring device causes a turning moment acting upon the flap.

The sheath of the telescopic spring device is connected to the frame in constant distance from the turning axis of the flap, and the free end of the rod of the spring device is connected with the flap, also in fixed distance from the turning axis.

When the flap is closed, the rod of the telescopic device is pressed into the sheath, keeping the spring device in readiness to act when the flap is being unlocked from the frame. The direction of the force of the rod along the telescopic device forms an angle with the plane of the flap (sash) and is decomposed into two components, a parallel one and one perpendicular to the flap plane. The lesser the angle between the force of the spring device and the flap frame, the greater is the parallel constituent of the force, not compensated by the weight of the closed flap. The smaller, upright constituent of the force, perpendicular to the flap plane, is directed upwards and partly compensates the weight of the flap, making it less heavy, which is essential particularly at the beginning of the raising movement. When the flap rests on the frame, the constituent force parallel to the frame forces the flap to move on the window frame within a range limited by the construction clearances of the closure and due to the elastic strain of the fittings of the enclosure. This is disadvantageous

for the esthetics of the closure and often leads to loss of tightness along one of its sides, as well as jamming of its elements on the opposite side.

When the location of the connections points of the telescopic spring device with the frame and the flap are fixed, then the angle between the force of the spring device and the plane of the flap increases during opening. This causes a disadvantageous change of the proportion between the constituents of the spring device force, because the values of the parallel and perpendicular constituents near together. The increase of the perpendicular constituent results in the acceleration of flap movement in the final phase of turning, when the flap is perpendicular to the frame, causing the inertial force of the flap to exert a heavy load on the fittings of the mechanism.

The aim of the invention is providing a mechanism assisting the opening of flap closures, especially of tilting and turning roof window sashes, which mechanism, when the roof window or hatch is closed, is ready to assist opening of the flap (sash or cover), but in which the constituent of the spring force acting parallel to the plane of the flap is balanced and the flap stably rests on the frame, and which mechanism, during opening the flap, minimizes its violent movement at the final phase of opening.

The assisting mechanism according the invention has a spring device the elements of which shift against each other during the opening movement, and that shifting is forced by a spring. The spring device is connected with the elements of the flap closure, one end of the spring device being connected with an element of the frame or the flap in fixed distance from the turning axis of the flap, whereas the second end of the spring device is shifting along the flap closure, on the flap or the frame respectively. The assisting mechanism has besides also a rigid element connected by one end with the shifting end of the spring device, and by the opposite end with that element of the hatch or window, which is connected to the spring device. The locations of the elements of the spring device and of the rigid element are distant from one other.

The assisting mechanism of such a construction provides that when the flap is in closed position, the spring device is ready to assist opening, but the assisting mechanism is in state of equilibrium, as the constituent of the spring force

acting in the direction parallel to the plane of the flap is balanced by the rigid element and the constituent perpendicular to the plane of the flap partly compensates the weight of flap, which eases its opening in the initial stage of opening.

During the turning movement of the flap, the rigid element of the assisting mechanism smoothly moves the sliding end of the spring mechanism towards the axis of rotation of the flap. This causes that the angle between direction of the force of the spring device and the plane of the flap changes less than when both ends of the spring device are connected with the hatch or roof window. Therefore, the proportion between the constituents of the force changes to a small, negligible degree and the flap opens in the final phase smoothly.

The assisting mechanism is connected with the elements of the hatch or roof window in a manner enabling disconnection, making it possible to dismantle the flap (sash or cover) from its frame, which is particularly important in the case of roof windows.

The assisting mechanism according the invention is presented by examples of execution in drawings, which in Fig. 1 and Fig. 2 show the hatch or roof window fitted with the assisting mechanism in the open and respectively closed positions, with the sliding element of the spring element moving on the frame, whereas Fig. 3 and Fig. 4 show the hatch or roof window fitted with the assisting mechanism in the open and respectively closed positions, with the sliding element of the spring element moving on an element of the flap.

Example 1

The assisting mechanism has a telescopic device consisting of the cylinder 1 and rod 2 of a gas spring. The cylinder is fixed in an articulated way with the element 4 of the flap at some distance from the turning axis of the flap, determined by the hinges. The free end of the rod 2 is connected in an articulated way with the sliding element 5. Along the frame element 6, close to turning axis of the flap, is fixed the U-shaped guide 7, which has the ends of its arms bent inside. The sliding element 5 moves inside the guide 7.

The assisting element has also a rigid arm 8, which is connected in an articulated way at one end with the sliding element 5, and at the opposite end with the fixture on the flap element 4, close to its turning axis.

When the flap is in closed position, the rod 2 is slid inside the cylinder 1 and the telescopic device is in readiness to assist opening of the flap. The rigid arm 8 of the assisting mechanism holds the rod 2 with the sliding element 5 at its end located inside the guide 7, at maximum distance from the turning axis of the flap. When the flap is being raised, the rod 2 of the gas spring slides out of the cylinder 1 , and the rigid arm 8 of the assisting mechanism, which is connected with the free end of the rod 2 and the sliding element 5, moves inside the guide 7 towards the turning axis of the flap. This causes that the angle between the direction of the force of the spring device and the plane of the flap is similar to the angle between the same elements when the flap is closed, so that at the end of the movement the flap opens smoothly.

The bent towards each other arm ends of the channel-like guide 7 keep the sliding element 5 from lifting out of the guide 7, which limits the turning range of the flap; that range is being determined by the length of the rod 2 of the gas spring slid out completely and the length of the rigid arm 8, as well as by the location of their connection points with the elements of the closure (hatch or roof window). The connection of the cylinder 1 and the rigid arm 8 with the flap element 4 can be dismantled, which makes it possible to remove the flap from the roof window frame.

Example 2

The assisting mechanism has a telescopic device consisting of the cylinder 1 and rod 2 of a gas spring. The cylinder is fixed in an articulated way with the sliding element 5 and the free end of the rod 2 is connected in an articulated way with the fixture 3 set on the element 6 of the flap frame at some distance from the turning axis of the flap, determined by the hinges. Along the flap element 4, at a distance from the turning axis of the flap, is fixed the U-shaped guide 7 with a longitudinal cut-out 10 in its side arm. The sliding element 5 is a counterpart of the longitudinal cut-out 10 in the guide 7.

The assisting mechanism has also a rigid arm 8, which is connected in an articulated way on one end with the sliding element 5, and at the opposite end with the fixture 9 on the element 6 of the frame of the flap closure, close to the axis of rotation of the flap (sash or cover).

When the flap is in closed position, the rod 2 is slid inside the cylinder 1 and the telescopic device is in readiness to assist opening of the flap. The rigid arm 8 of the assisting mechanism holds the cylinder 1 connected with the sliding element 5 end located inside the guide 7 at maximum distance from the turning axis of the flap.

When the flap is being raised, the rod 2 of the gas spring slides out of the cylinder 1 , and the rigid arm 8 of the assisting mechanism moves the sliding element 5 together with the cylinder 1 placed in the longitudinal cut-out 10 in the guide 7 towards the turning axis of the flap, and at the end of the movement the flap opens smoothly.

The sliding element 5 moving along the longitudinal cut-out 10 is protected against moving out of the guide 7, which limits the turning angle of the flap, and its range of turning is determined by the length the totally expanded rod 2 of the gas spring and the length of the rigid arm 8, as well as by the location of their connection with the elements of the flap closure.

The connection of the rod 2 and the rigid arm 8 with the element 6 of the frame is dismountable, which makes it possible to remove the flap (sash or cover) from the frame.