Door closer

Abstract: A door closer including a casing-like body (1) enclosing a piston member (2), which is movable back and forth according to the movements of a door or the like and which cooperates with a least one closer spring (6), and a closer shaft (4) with a pinion member (5) connected thereto for transmitting the force of the movement of the door or the like to the piston member (2), whereby the pinion member (5) is mounted on the closer shaft (4) eccentrically with regard to its rolling curve (5a). The piston member (2) has a casing-like form and is provided with a rack (3) arranged at its inner surface, having a rolling curve (3a) which is at least substantially linear and which is arranged transversely relative to the direction of movement of the piston member (2). The pinion member (5) is located inside the piston member (2) and has teeth meshing with teeth of the rack (3) so that the force transmitting moment of the pinion member (5) is at its maximum in a position corresponding to the closed position of the door or the like.

Description: This invention relates to a closer for a door or the like according to the preamble of claim 1. In this specification the term "door closer" is intended to cover not only a closing device for a door but also a closing device for any other type of closure member, e.g. a window or the like. It is of advantage both from the viewpoint of installation and outward appearance for a door closer to be compact in size and of simple form. Advantageously this can be achieved by using a casing-like piston to which force transmission occurs through a pinion arranged on a closer shaft located inside the piston. A door closer of this known kind is disclosed for instance in GB-A-2008666. From the viewpoint of the operation of a door closer, it is of advantage that the door should be opened by exerting a force of reasonable size and yet closing of the door would still be ensured. For this purpose different hydraulic arrangements and closer spring solutions have been utilised but in practice they are rather complicated and often unsatisfactory in operation. The utilisation of an eccentric pinion provides a simpler solution, whereby the changing moment transmitted by the pinion during the opening movement of the door together with the changing force of a closure spring makes possible an advantageous operation of the door closer. FR-A-966945 discloses one solution of this kind. However this known device is unsatisfactory especially from the viewpoint of utilisation of space. Another solution is disclosed in EP-A-0243786 but in this case the drawbacks are, inter alia, manufacturing problems and costs caused by the use of differently shaped teeth. An aim of the invention is to provide a door closer which is constructionally simple and operationally advantageous from the viewpoint of force transmission and from which the drawbacks apparent in the above mentioned solutions have been eliminated. According to the invention there is provided a door closer as claimed in the ensuing claim 1. By arranging for the force transmitting moment of the pinion member to be at its maximum in a position corresponding to the closed position of the door or the like, power is provided for the closing moment of the door, even if the closer spring is, in this phase, not compressed more than to the extent of prestress. Thus the door closer can be provided with a closer spring which has a correspondingly smaller spring force than is normal for door closing purposes. On the other hand at or near the fully open position of the door, the force transmitting moment transmitted by the pinion member can be arranged to be relatively small whereas at the same time the compressive stress of the closer spring is increased. Thus the initial phase of closing of the door from an open position can be reliably accomplished. A door closer according to the invention can be made of an advantageous size and form. In addition the solution makes it possible for the teeth of both the pinion member and the rack means to be implemented as standard toothing, which is of advantage from the viewpoint of manufacturing technique. For a door closer according to the invention, the meshing angle between the pinion member and the rack means does not remain theoretically quite correct, but changes somewhat within the range of movement whereby the clearance between the pinion member and the toothed rack in the piston changes at the same time. In practice, however, this is not significant, since the obliquity of the toothed rack in the piston compensates for the change. If required this matter can also be influenced by providing the teeth with a suitable shape, by optimizing the number of teeth utilized and/or by selecting materials so as to improve the strength of the teeth. The angle between the rolling curve of the toothed rack and the direction of movement of the piston member is with advantage selected to be from 4.5° to 7.2°. In practice for larger door closers, intended for use with doors of relatively large mass or, for example, for use with doors in windy locations, this angle is selected to be from 4.5° to 6.5°, preferably from 5.5° to 6.2°. Thus a compact solution is obtained, which is more advantageous from the viewpoint of the requirements for the strength of materials. In smaller door closers intended for use with doors with relatively small mass, in which the requirements for the strength of materials are correspondingly smaller, the angle may with advantage be selected to be from 6.5° to 7.2°, whereby a greater change in the force transmitting moment can be obtained. Naturally the change of angle must be taken into account and also the eccentricity of the pinion member so that a larger value for the angle corresponds to a larger eccentricity. An embodiment of the invention will now be described, by way of example only, with particular reference to the accompanying drawing, in which: Figure 1 shows a door closer according to the invention in an operational position corresponding to a closed position of a door; and Figure 2 shows the door closer of Figure 1 in an operational position corresponding to an open position of a door. In the drawing 1 indicates a casing-like body of a door closer enclosing a piston 2, which is in force transmitting connection with a door or the like (not shown) so that, when the door is opened, the piston 2 moves from the position of Figure 1 in the direction of the arrow against the force of a closer spring 6 into the position of Figure 2. The force transmission is accomplished by means of a pinion member 5 mounted on a closer shaft 4 and provided with teeth which mesh with teeth of a rack 3 in the piston 2. As is apparent from Figures 1 and 2, a rolling "curve" 3a of the rack 3 of the piston is straight throughout its length and forms an angle B with an axis A representing the direction of movement of the piston 2 within the body 1. The pinion member 5 is mounted on the closer shaft 4 eccentrically with regard to its rolling curve 5a. Consequentaly, in the situation of Figure 1 when the door is closed, the lever arm R1 of the force transmitting moment to be transmitted by the pinion member 5 is substantially larger than the corresponding lever arm R2 of the force transmitting moment in the situation of Figure 2 when the door is open. Thus the force transmitting moment changes independently of the compressing force of the closer spring 6, which is of advantage from the viewpoint of the operation of the door closer. The change in the lever arm of the force transmitting moment from R1 to R2 illustrates at the same time the change in the distance between the closer shaft 4 and the rolling curve 3a of the piston, which is compensated by arranging the rolling curve 3a at a certain angle B with regard to the axis A of the direction of movement of the piston. As already recited above, by means of this arrangement it is not possible to provide an equal theoretically ideal rolling situation between the teeth of the members 3 and 5 compared with when the distance in question remains unchanged. The arrangement, however, is advantageous from the viewpoint of force transmission and the problems relating to the strength of materials can be managed by the selection of the materials as well as by utilising a different angle B in closers of different size, i.e. with different spring stiffnesses. Thus in larger door closers, i.e. door closers with "stiffer" springs in which the spring force is bigger, small values are used for the angle B so as to prevent extra or excessive friction during rolling. The angle B may then with advantage be for instance 5.8°, whereby the eccentricity of the pinion member 5 can be 1.5 mm. In smaller closers, i.e. spring closers having springs of less stiffness and less spring force, in which the requirements for the strength of materials are correspondingly smaller as well, a value of 6.6° may, for example, be used for angle B, whereby the eccentricity of the pinion member 5 is with advantage 2 mm. This arrangement, in which the spring force of the spring 6 is relatively small, allows a larger angle B without adversely affecting rolling friction and provides a more advantageous change in the moment lever arm. However from the viewpoint of the strength of the materials it is a somewhat more disadvantageous arrangement. The invention is not limited to the embodiment shown, but several modifications are feasible within the scope of the accompanying claims.

Claims: A door closer including a casing-like body (1), a casing-like piston member (2) which is movable back and forth within the body (1) according to the movements of a door or the like and which is provided with rack means (3) at an inner surface thereof, at least one closer spring (6) in cooperation with the piston member (2) and a closer shaft (4) with a pinion member (5) connected thereto for transmitting the force of the movement of the door or the like to the piston member (2), the pinion member (5) being mounted on the closer shaft (4) eccentrically with regard to its rolling curve (5a), being located inside the piston member (2) and having teeth meshing with teeth of the rack means (3) so that the force transmitting moment of the pinion member (5) is at its maximum in a position corresponding to the closed position of the door or the like, characterised in that the rack means has a rolling curve (3a) which is linear throughout its length and which is arranged at an angle relative to the direction of movement of the piston member (2), and in that the rolling curve (5a) of the pinion member (5) is in the form of a circle or an arc thereof such that the teeth of both the pinion member (5) and the rack means (3) can be implemented as standard toothing. A door closer according to claim 1, characterised in that the angle (B) between the rolling curve (3a) of the rack means and the direction of movement (A) of the piston member (2) is from 4.5° to 7.2°. A door closer according to claim 2, characterised in that the said angle (B) is selected to be from 4.5° to 6.5°, preferably from 5.5° to 6.2°. A door closer according to claim 2, characterised in that the said angle (B) is selected to be from 6.5° to 7.2°.

Inventors: JUNTTILA JAAKKO, KAERKKAEINEN VESA, JUNTTILA, JAAKKO, KAERKKAEINEN, VESA, Kärkkäinen, Vesa
Applicants: ABLOY OY
Application year: 1998
Main classification: E05F3
IPC codes: E05F3