CURTAIN

DESCRPTION

The present patent concerns drop curtains and in particular concerns a new locking and unlocking device for curtains.

Drop curtains consist of a piece of fabric which is rolled and unrolled over a roller bar, by a rod applied on the free edge of the fabric and by two side guides along the edge. The fabric is unrolled from the roller bar, by means of a crank handle connected to a geared mechanism or a motorized mechanism; the weight of the lower rod facilitates the unrolling of the fabric and keeps it substantially taut. The ends of the lower rod are led by- taut cables or metal guides on the sides.

Drop curtains are simple to produce and maintain.

Drop curtains are very practical to provide shade for outdoor areas and to limit solar radiation.

However, drop curtains have several drawbacks related to the wind.

Indeed, the curtain fabric is inflated and lifted by the wind in the same way in which a sail is inflated by the wind.

This lifting action on the curtain results in the bouncing of the lower rod with the risk of damage to property and injuries to persons nearby.

One solution sometimes adopted to restrict the movement of the lower rod consists of making the lower rod itself heavier but this strategy has the disadvantage of making the rewinding of the curtain fabric more difficult and laborious. In addition, the increased weight of the lower rod does not impair the movement of the curtain and the lower rod itself in the case of strong winds.

Other solutions adopted to prevent the movement in question, and in particular the lifting movement of the lower rod, consist of mechanically locking the lower rod to vertical side guides: for example, the ends of the lower rod are constrained to the side guides with pins and hooks which cross the guide and the ends of the lower rod, or cross the guides above the ends of the lower rod. These solutions require the direct manual intervention of the user to insert and extract the locking pins or hooks from one end and then from the other.

In the case of large curtains and _' Or curtains equipped with heavier lower rods two people are needed, one to hold the curtain and the relative lower rod in the correct position while the other person inserts or hooks the aforementioned pins or hooks.

To overcome all the above drawbacks a new automatic device to lock and release sliding curtains, whether vertical or inclined, was developed and constructed.

One purpose of the new mechanism is to prevent the lower rod of the curtain from being unintentionally lifted.

Another purpose of the new mechanism is to be automatically activated to prevent the lower rod of the curtain from lifting without the direct intervention of the user.

A further purpose of the new mechanism is to be automatically activated to allow the lifting of the lower rod of the curtain without the direct intervention of the user.

Yet another purpose of the new mechanism is to have a locking device that does not need to be electrically powered to operate, and which therefore does not require maintenance since it functions by balance as a result of gravity.

Another purpose of the new mechanism is to be safe for curtain operators and users. These and other purposes, direct and complementary, are achieved by the new automatic locking and releasing device for drop curtains comprising a terminal element to be applied at least to one end of the lower rod and a rotary cam to be fixed to the upright or guide corresponding to the terminal element.

The rotary cam is made up of an element consisting of two parts, one is the locking portion and the other is the counterweight part generally opposite with respect to the rotation through-hole.

The locking portion has an angled shape, consisting of a first portion generally radial with respect to the rotation through-hole and a second portion angled about half a right angle with respect to the first portion.

The end of the second portion of the locking portion i s preferably rounded. The counterweight part has a generally a circular section shape with the centre of rotation approximately located in the aforementioned rotation through-hole.

The weight of the counterweight is greater than the weight of the locking portion so as to guide the rotary cam, free to rotate around its rotation through-hole having a horizontal axis, with the locking portion generally directed upwards.

The rotary cam is applied inside the guide through which the terminal element or end of the curtain's lower rod runs.

In particular, the rotary cam is fixed inside the aforementioned guide with a pin or other element passing through the rotation through-hole of the rotary cam allowing the rotation on a horizontal axis orthogonal to the guide and to the lower rod of the drop curtain.

The terminal comprises an element suited to be applied to one end of the lower rod and has, on its sliding edge inside the guide or upright, a lower hook-shaped projection, an intermediate seat or groove, and an upper projection.

The lower hook-shaped projection has a generally L-shape with a first portion facing the opposite direction from the rod to which the terminal element is applied, and a second portion facing upward.

This lower hook-shaped projection constitutes, together with the edge facing towards the inside of the guide, a seat suited to receive the second portion of the locking portion of the aforementioned rotary cam.

The upper projection has a generally triangular shape, it faces the opposite direction with respect to the lower rod to which the terminal is applied and has at least the same side dimensions of the lower hook-shaped projection.

The intermediate seat or groove is preferably located in the upper part of the side edge of the terminal element, close to the upper projection.

This intermediate seat or groove is recessed towards the lower rod with respect to the two upper and lower projections such as to house the locking portion of the rotaiy cam oriented towards the opposite end of the lower rod. The characteristics of the new automatic locking and releasing device for curtains will be better clarified by the following description with reference to the attached drawings, by way of a non-limiting example.

Figures l a and lb show respectively a top view and a side view of the rotary cam (C) comprising a locking portion (CI) and a counterweight portion (C2) generally opposite with respect to a rotation hole (C3).

The locking portion (CI) has an angled shape, consisting of a first portion (CI a) generally radial to the rotation hole (C3) and a second portion (Clb) angled approximately half a right angle with respect to the first portion (Cla).

The counterweight portion (C2) has a generally circular section shape with the centre approximately in the rotation hole (C3).

The weight of the counterweight portion (C2) is greater than the weight of the locking portion (C I) so as to guide the rotary cam (C), free to rotate around its rotation hole (C3) with a horizontal axis, with the locking part (CI) generally oriented upwards.

Figures 2a and 2b show respectively a top view and a side view of the terminal element

(T) suited to be applied at one end of the lower rod (A) of a drop curtain.

This terminal element (T) has, on its edge (Tb) sliding inside the guide (G) or upright, a lower hook-shaped projection (Tl), an intermediate seat or groove (T2) and an upper projection (T3).

The lower hook-shaped projection (Tl) is generally L-shaped with a first portion (Tla) facing the direction opposite the rod (A) to which the terminal element (T) is applied and a second portion (T l b) lacing upwards.

This lower hook-shaped projection constitutes, together with the edge (Tb) facing the inside of the guide (G), a seat (Ts) suited to house the second portion (Clb) of the locking portion (C I) of the rotary cam (C).

The upper projection (T3) has a generally triangular shape, faces the direction opposite the rod (A) to which the terminal element (T) is applied and has side dimensions at least identical to the side dimensions of the lower hook-shaped projection (Tl). The intermediate seat or groove (T2) is preferably arranged on the upper part of the side edge of the terminal element, near the upper projection (T3).

This intermediate seat or groove (T2) is recessed towards the lower rod (A) of the curtain with respect to the two upper projections (T3) and lower projections (Tl) by a length that is sufficient to house the locking portion (CI) of the rotary cam (C) oriented towards the opposite end of the lower rod (A) of the drop curtain.

Figure 3 shows how the locking cam (C) and the terminal element (T) are applied respectively in the guide (G) and on the end of the lower rod (A) of the drop curtain. This figure clearly shows how the rotary cam (C) has the counterweight portion (C2) generally downward and the locking portion (CI) inclined upward and towards the centre of the drop curtain when it is in its normal position.

Figures 4a, 4b, 4c, 4d, 4e, 4f, 4g, and 4h show various phases of the use of the new device for the automatic locking and releasing of curtains.

The locking cam (C) is hinged into the guide (G), so as to rotate on the drop curtain's fabric plane and the sliding plane of the lower rod (A).

In this example the locking cam (C) is hinged to a support section (P) in turn fixed to the guide (G) of the drop curtain.

The terminal element (T), sliding in the guide (G) is applied to the end of the lower rod (A) of the drop curtain.

Figures 4a. 4b, 4c, and 4d show the most relevant phases of the locking sequence of the lower rod (A) of the drop curtain:

Figure 4a: The drop curtain is lowered and the terminal element (T), in its descending movement, meets the locking portion (CI) of the rotary cam (C);

Figure 4b: The descent of the lower rod (A) and the respective terminal element (T) makes the first lower hook-shaped projection (Tl) push the locking portion (CI) of the rotary cam (C) down by rotating the cam (C) itself;

Figure 4c: The further descent of the lower rod (A) and the terminal element (T) brings the first lower hook-shaped projection (Tl) of the terminal to a height lower than the rotary earn (C), allowing the rotary cam (C) itself to rotate in the reverse direction while maintaining the generally downward orientation; in this position the first portion (CI a) of the locking portion (CI) essentially adheres to the edge (Tb) of the terminal element (T) between the first lower hook- shaped projection (Tl) and the intermediate seat or groove (T2);

Figure 4d: When the drop curtain is lifted, the lower rod (A) and the terminal element (T) are raised with the consequence that the first portion (CI a) of the locking portion (CI) of the rotary cam (C) is housed in the seat (Ts) formed by the first lower hook-shaped projection (Tl) of the terminal and from the edge (Tb) of the terminal element (T), preventing the upward rotation of the rotary cam (C) and preventing the lifting of the terminal element (T) and of the lower rod (A) of the drop curtain.

Figures 4e, 4f, 4g, and 4h show the most relevant phases of the sequence for unlocking the rod (A) of the drop curtain:

Figure 4e: The drop curtain is lowered so that the lower rod (A) and the terminal element (T) translate downwards, so that the first portion (CI a) of the locking portion (C 1 ) of the rotary cam (C) exits the seat (Ts) formed by the first lower hook-shaped projection (Tl ) of the terminal and from the edge (Tb) of the terminal element (T) while remaining generally oriented downwards and adhering to the edge (Tb) of the terminal element (T);

Figure 4f: The descent of the lower rod (A) and the terminal element (T) brings the intermediate groove (T2) of the terminal element (T) to the height of the rotary cam (C), so as to enable the rotation of the rotary cam (C), until the locking portion (CI) of the rotary cam (C) itself is oriented generally horizontally;

Figure 4g: At this point, the translation direction of the drop curtain is inverted by raising the lower rod (A) and the terminal element (T); the locking portion (CI) of the rotary cam (C) is rotated upward, by rotating the cam (C) itself, and subsequently runs along the edge (Tb) of the terminal element (T) and on the first lower hook-shaped projection (Τί) of the terminal element (T) without stopping the lifting of the curtain, the lower rod (A) and the terminal element (T);

Figure 4h: The further lifting of the drop curtain, the lower rod (A) and the terminal element (T) raises the terminal element (T) beyond the position of the rotary cam (C), allowing the rotary cam (C) itself to return to its normal position.

According to the invention, a greater number of rotary cams (C) can be applied along the height of the guide (G) of the cuitain so as to allow the locking of the lower rod (A) of the drop curtain at the desired height.

During the descent, the terminal element (T) rotates the rotary cams (C) not involved in the locking of the lower rod (A) according to the sequence of Figures 4a, 4b, 4c, 4e, and 4f and continuing the descent without being blocked since the upper projection (T3) of the terminal element (T) rotates the locking portions (CI) of the rotary cams (C) downward. The locking of the lower rod (A) and the terminal element (T) occurs at the height of the appropriate rotary cam (C) according to fhe sequence already described in Figures 4a, 4b, 4c, and 4d.

After releasing the terminal element (T) and the lower rod (A) of the curtain according to the sequence in Figures 4e, 4f, 4g, and 4h, the drop curtain, the lower rod (A) and the terminal (T) are not prevented from going back up since the upper projection (T3) of the terminal element (T) rotates the locking portions (CI) of the rotary cams (C) and the rotary cams (C) themselves upward, and the terminal element (T) and the rotary cams (C) behave as shown in Figures 4g and 4h.

Therefore, with reference to the preceding description and the attached drawings, the following claims are made.