The present invention concerns a locking mechanism comprising a lock case with a beveled latch bolt movable in and out, a first operating spindle for the door han¬ dle and a second operating spindle for a locking element inside the door, such as a thumbturn mechanism or a key cylinder, said lock case having a transmission connection between the first operating spindle and the second operating spindle for moving the beveled latch bolt inside the lock case by turning the door handle, said transmission connection being formed by turning the second operating spin¬ dle to a suitable position. The invention also concerns a thumbturn mechanism.

Lock bodies having a beveled latch bolt moving into and out from the lock case are used in locking solutions for doors. In the locking position, the beveled latch bolt moves out from the lock case and sets itself into an aperture formed into a striker plate located in the doorframe. When the door is opened, the beveled latch bolt is retracted inside the lock case, whereby the door can be opened without being pre¬ vented by the beveled latch bolt. A lock case having a first operating spindle for the door handle and a second operating spindle for a key cylinder outside the door and for a thumbturn inside the door is generally used nowadays. This kind of a lock case is known for example from the patent publication Fl 101240. A transmis¬ sion connection is provided between the first operating spindle and the beveled latch bolt so that the beveled latch bolt is retracted into the lock case by turning the handle connected to the first operating spindle. The transmission connection be¬ tween the beveled latch bolt and the first operating spindle is formed by means of a key cylinder or a thumbturn connected to the second operating spindle.

The above mentioned lock case can be set to two different operating positions. In the so-called normal use, the beveled latch bolt is in the locking situation extended out from the lock case for its total length. Thereby the door is locked to the so- called deadlock position. The opening of a deadlocked door requires in that case always turning of the thumbturn or the cylinder key first to the opening position, after which the beveled latch bolt is retracted into the lock case by turning the handle. The lock case can also be set to the so-called day use position, in which the beveled latch bolt is extended in the locking situation out from the lock case, but only to about a half of its length. In the day use position, the transmission con¬ nection between the beveled latch bolt and the second operating spindle is con¬ tinuously connected, whereby the lock opens simply by turning the handle. The wanted operating position of the lock is chosen by means of a selection knob lo- cated on the visible side of the lock case.

Many disadvantages are associated with the locking mechanism known in the art. During day time when people are at home, the day use position is often experi¬ enced to be more comfortable, because it is possible to go in and out through the entrance doors of the building without using keys or thumbturns. It is, however, troublesome to set the lock case to the day use position, because the selection knob of the operating position is small-sized and located in a difficult place on the side facing towards the doorframe. The use of the selection knob is especially dif¬ ficult for weak-eyed elderly people and people suffering from different disabilities or illnesses like rheumatism.

It is also often difficult for the residents to know, in which operating position the lock case is, because the selected operating position is not at all visible outside, when the door is closed. This has easily as a result that the resident locks him/herself outside the house, when the lock case for some reason is not in the supposed day use position. In case of aged people living alone this kind of a mis- take can in the worst case be fatal.

The aperture in the striker plate of the doorframe for receiving the beveled latch bolt is formed so that the beveled latch bolt cannot be extended totally out from the lock case before the door is pulled tightly against the sealing. In the day use posi¬ tion, when the beveled latch bolt is not extended totally out from the lock case, the door panel is not pressed with the same force against the sealing, which results in uncontrolled air leakages. This phenomenon gets worse in the course of time, be¬ cause doors tend to twist and warp with age. Air leakages are harmful especially in hard freeze conditions, causing feeling of draft and increasing energy consump¬ tion. The aim of the present invention is to provide an improved locking mechanism and thumbturn mechanism in order to significantly decrease drawbacks and disadvan¬ tages associated with prior art.

The aims in accordance with the invention are achieved with a locking mechanism and a thumbturn mechanism characterized by what is stated in the independent claims. Some preferred embodiments of the invention are disclosed in the de¬ pendent claims.

The object of the invention is a door locking mechanism comprising a lock case with a beveled latch bolt movable in and out, a first operating spindle for the han- die of the door and a second operating spindle for the locking element inside the door, such as a thumbturn mechanism or a key cylinder. A transmission connec¬ tion is arranged between the first operating spindle of the lock case and the bev¬ eled latch bolt so that the beveled latch bolt can be retracted into the lock case by turning the handle connected to the first operating spindle. This transmission con- nection is formed by moving the second operating spindle first to a suitable posi¬ tion by means of a locking element inside or outside the door, like a thumbturn mechanism or a key cylinder with a key. The basic idea of the invention is that the locking mechanism is provided with means for locking the second operating spin¬ dle from inside the door to said position forming a transmission connection for a period of time wished by the user. The lock case is set to operate continuously in the normal using position, but due to the invention, the user can easily set the lock case to operate like in the day use position without opening the door.

In a preferred embodiment of the invention, the inside locking element, such as a thumbturn mechanism or a key cylinder, is connected to the second operating spindle with a shaft pin known in the art and the means for locking the second op¬ erating spindle comprise a locking element for locking the shaft pin to the desired position. The locking element is preferably an annular friction member adapted around the pin, said friction member being attached to the lock case, or a thumb- turn mechanism with a locking mechanism for locking the thumbturn to the desired position. An advantage of the invention is that it facilitates significantly the use of the locking mechanism, because the selection knob of the operating position, difficult to use, is not needed at all.

A further advantage of the invention is that the locking mode of the door is easily recognized from the position of the thumbturn when the door is closed. This in¬ creases the security of residents, because situations where they unintentionally lock themselves outside, and, on the other hand, leave the door unlocked, occur more seldom.

Still a further advantage of the invention is that it decreases the heating energy consumption of the building and increases the comfort of living, because uncon¬ trolled air leakages are decreased.

The invention will be described in more detail in the following with reference to the enclosed drawings, wherein

Figure 1a shows, as an example, an exploded view of a thumbturn mechanism in accordance with the invention,

Figure 1b shows, as an example, a cross-sectional view of a thumb- turn mechanism in accordance with the invention,

Figures 2a and 2b show, as an example, an installed thumbturn mechanism in accordance with the invention, and

Figures 3a and 3b show, as an example, one preferred embodiment of the locking mechanism in accordance with the invention.

Figure 1a shows as an example an exploded view of a thumbturn mechanism in¬ cluded in a locking mechanism in accordance with the invention. The thumbturn mechanism comprises a rather thick plate-like thumbturn 10, the outer surfaces thereof being formed to be easily gripped and suitable to hand. On the first narrow side face of the thumbturn there is a pipe-like shaft 12 projecting from the level of the side face, said shaft having at its free end two projections 14 arranged parallel to the shaft and having a cross section of a circular arc. A groove 22 is formed on the outer surface of the projections for receiving a locking ring 24. The thumbtum mechanism further comprises a round cover plate 16 to be set against the door panel, with a through hole 18 for the shaft 12 of the thumbtum. The cover plate has two mounting holes 20 for attaching the cover plate with fixing screws to be driven through the holes. The mechanism further includes a spacer 26 having holes on its opposite edges for the projections 14 of the end of the shaft 12 of the thumbtum 10. In the middle of the spacer there is a rectangular hole for the shaft pin 38 (Figure 1 b) connecting the second operating spindle of the lock case and the thumbtum.

All components described above are well known and used in the thumbtum mechanisms of prior art. In addition to those components, the thumbtum mecha¬ nism of the present invention comprises a thrust ring 28 made of elastic material. The thrust ring 28 can be made of any suitable elastic material like rubber, plastic material or silicone. Preferably the thrust ring is made of Teflon. The size of the thrust ring is chosen so that it can be placed around the shaft 12 of the thumbtum. The invention further comprises a locking pin 30 adapted to a hole 32 bored to the first side face of the thumbtum. Preferably the locking pin has a length of 10 mm and a diameter of 6 mm. The end of the locking pin leaving outside the hole has a conical form about for a length of 2 mm. The diameter of the hole 32 is chosen so that only a clearance allowing the locking pin to move is left between the wall of the hole and the outer surface of the locking pin. The hole is formed to have a big¬ ger depth than the length of the locking pin in order to leave space for a spring element 34 (Figure 1 b) on the bottom of"the hole. The spring element can be, as shown in the figure, a helical spring or another suitable element, like a piece of some elastic material. The thumbtum mechanism further comprises two locking recesses 36 being formed on the outer surface of the cover plate. The distance of the locking recesses from the centre of the shaft hole 18 is equal to the distance of the locking pin 30 from the central line of the shaft 12.

Figure 1 b shows as a cross-sectional view a thumbtum mechanism in accordance with the invention, assembled ready for operation. In the assembling phase of the thumbtum mechanism, the spring element 34 has been located on the bottom of the hole 32 and the locking pin 30 is mounted in place in the hole, the conical head thereof projecting outwards. After that, the shaft 12 of the thumbtum 10 is adapted through the shaft hole 18 of the cover plate 16, and the thrust ring 28 is placed around the shaft. Finally, the spacer 26 is mounted to the projections 14 of the shaft end and the locking ring 24 is installed. The thickness of the thrust ring is chosen so that in the thumbtum mechanism ready for operation, the thrust ring will be slightly compressed between the cover plate 16 and the spacer 26. Therefore the compressed thrust ring "pulls" the first side face of the thumbtum 10 tightly against the surface of the cover plate. This causes friction forces between the thumbtum and the cover plate preventing the thumbtum from turning freely. The friction forces are, however, not too big to prevent the thumbtum from being turned by hand.

The compressed spring element 34 in the hole 32 of the thumbtum pushes the locking pin 30 continuously outwards from the hole. When the thumbtum is turned into a position, where the locking pin is aligned with the locking recess 36 of the cover plate 16, the spring element pushes the head of the locking pin into the lock¬ ing recess. The locking pin and the locking recess cause thereby the same effect as the thrust ring, in other words, they lock the thumbtum into a desired position. The friction force of the thrust ring and the pressing force of the spring element pushing the locking pin, however, are even altogether so weak that the thumbtum can be easily turned into different positions by hand. The thumbtum mechanism in accordance with the invention can naturally also be implemented so that only one of the arrangements described above, for locking the thumbtum, is mounted into it.

When the thumbtum is in the vertical position as shown in Figure 1 b, the head of the locking pin 30 sets into the first locking recess 36. The thumbtum is thereby in the opening position, in which it, when assembled to a door panel and connected to the lock case, forms a transmission connection between the beveled latch bolt and the door handle. When the thumbtum is turned about for a quarter turn counter-clockwise, the head of the locking pin sets to the other locking recess. The thumbtum is thereby substantially in the horizontal, locking position, not forming the above mentioned transmission connection when assembled in place. The user of the door can turn an assembled thumbtum between these two positions by hand. When the locking pin is aligned with the locking recess, a weak click is heard telling the user that the thumbtum is in one of its two limit positions. Colored signs are preferably painted onto the cover plate, at the places of the locking re¬ cesses telling the user, which of the thumbturn positions is the locking and which is the opening position.

Figures 2 and 2b show, by way of an example, a thumbturn mechanism in accor¬ dance with the invention, assembled in place, in different positions of the thumb- turn. The thumbturn mechanism is meant for use in doors being equipped with a lock case 40 comprising a first operating spindle 42 for a door handle 46 and a second operating spindle 44 for a key cylinder outside the door and a thumbturn mechanism inside the door. A transmission connection must be arranged between the first operating spindle 42 and the beveled latch bolt 50 so that the beveled latch bolt is moved inside the lock case by turning the handle connected to the first operating spindle. Further, the transmission connection between the beveled latch bolt and the first operating spindle must be arranged so that it is formed by turning the second operating spindle into a suitable position. This kind of a generally used lock case is known for example from the Patent Fl 101240.

The thumbturn mechanism is attached inside the door panel 100 in a known way with fixing screws, and the thumbtum 10 is connected by means of a shaft pin to the second operating spindle 44 of the lock case 40. A handle is assembled to the first operating spindle 42 of the lock case, after which the locking mechanism is ready for use. When using the thumbturn mechanism in accordance with the in¬ vention, the lock case is kept continuously in the normal use position. The operat¬ ing position of the lock case is not needed to chance during the use at all, whereby the selection knob 48 of the operating position can be covered with tape, for ex- ample, after the correct operating position has been chosen.

When using the thumbturn mechanism in accordance with the invention, the user of the door chooses the way of operation for the door locking by means of the po¬ sition of the thumbturn 10. When the user wants the door to be locked each time when it is closed, he turns the thumbturn to the horizontal position as shown in Figure 2b. The lock case 40 acts then so that the beveled latch bolt 50 is extended totally out from the lock case, when the door is closed, in other words, the door is deadlocked. The beveled latch bolt can be retracted inside the lock case with the handle 46 only if the transmission connection is first created by means of the key cylinder or thumbturn. When the user wants the locking mechanism to operate in the day use position, he/she turns the thumbturn to the vertical position as shown in Figure 2a. Although the lock case is actually still in the normal use position, it operates now like in the day use position, because the thumbturn 10 is continu¬ ously in a position that connects the transmission connection between the handle 46 and the beveled latch bolt.

Thus, the beveled latch bolt can be moved inside the lock case as well from the outside as from the inside of the door simply by turning the handle. In the thumb- turn mechanism in accordance with the invention, the thumbturn 10 keeps con¬ tinuously in the position chosen by the user, even if the door is opened and closed several times. Thus, the user can for example turn the thumbturn for the daytime to the horizontal position, making it possible to go through the door simply by using the handle. Correspondingly, for the night time the thumbturn can be turned to the horizontal position, for locking the door as usual.

Figures 3a and 3b show, by way of an example, one preferred embodiment of the locking mechanism in accordance with the invention. Figure 3a shows this pre¬ ferred embodiment of the invention for the part of the second operating spindle 44 as a cross-sectional view and Figure 3b as a side view in section taken on the line A-A. The thumbturn is connected to the operating spindle 44 of the lock case in a way known in the art by means of a shaft pin 38 having at its one end a connecting piece 54 for connecting it to the second operating spindle. In the wall of the lock case, aligned with the operating spindle, there is a round hole 56 having a diame- ter bigger than the diameter of the connection part. In the invention, an annular friction member 52 is adapted to the inside of the hole, said friction member being made of a flexible material, preferably of Teflon. Because the friction member is located outside the wall of the lock case, the mounting thereof does not require any changes to the internal construction of the lock case. The friction member has an outer diameter that makes it set tightly inside the hole. The inner diameter of the friction member is slightly smaller than the diameter of the connecting piece 54 of the shaft pin. When put in place, the edges of the connection piece match with the inner surface of the friction member causing a small local compression at the points of contact to the friction member. Because of the tight mutual fitting of the connection piece 54, the friction member 52 and the hole, a friction force acts on the junction surfaces between those parts, preventing the shaft pin from turning freely. The friction force is, however, so small, that it does not prevent the shaft pin from being turned by hand by means of the thumbturn. The friction force can be set to the desired level by choosing a suitable wall thickness of the annular friction member. The connection between the second operating spindle and the connec¬ tion piece 54 is covered in a known way by means of a lock plate 58 set against the wall of the lock case, said lock plate securing at the same time the friction member in position.

Some preferred embodiments of the method and device in accordance with the present invention have been described above. The invention is not limited to the described solutions, but the inventive idea is applicable in various ways within the limits of the claims.