DOOR CLOSER

Abstract: A door closer provided on a door, for automatically closing the door by a restoring force in the direction of closing the door, which has been accumulated in a spring for returning operation during the opening operation of the door, while exhibiting a damping force by a damper. The main body (1) of the door closer having the above damping function is not directly attached to the door as in the conventional door closer, but, has an arm (7) projecting from the main body (1) of the closer, which is attached to the door (18) by use of a metal fixture (8) pivotally mounted on the arm (7), for mounting the door, thus enabling the closer to be installed in a small space. An adjust arm (10) connected to a driving shaft for damping the main body (1) of the closer and rotatably projecting is attached to a top frame (19) through a top-frame-mounting plate (14) pivotally mounted on the adjust arm (10), and arm intersecting angle made by the both arms (7 and 10) is decreased when the door (18) is fully opened, whereby the characteristics of a stopper for holding the thus fully opened state is dispensed with, and further, the decreased intersecting angle made between the arms makes it possible to improve the degree of freedom in design of the main body (1) of the closer. Top surfaces (7a and 10d), and bottom surfaces (7b and 10e) of the arm (7) and the adjust arm (10) respectively are made flush with each other, differences in stage D1 and D2 are made equal, and the aforesaid driving shaft is exposed to the respective top and bottom surfaces of the main body (1) of the closer, thus permitting either right- or left-handed use of the door. A plurality of articulations are provided in the adjust arm (10), and the metal fixture (8) for mounting the door and the plate (14) for mounting the top frame are made detachable from each other, thus simplifying and facilitating the attaching to the door, replacement and maintenance.

Description: This invention relates to a door closer having a return spring in which a recovering force is accumulated as the door is opened, the recovering force acting in the door closing direction against a braking effect provided by a damper of the door closer. A conventional door closer consists, as shown in Figs. 9 and 10, of a closer body a, an arm c fixed at one end thereof to a piston drive shaft b of the door closer body a, and an adjusting arm g pivotally secured at one end thereof to the free end of the arm c via a screw d, and pivotally secured at the other end thereof to a mounting plate e via a screw f. The door closer body a has a hydraulic cylinder (not shown) in a body case a' and a piston (not shown) telescopically movable into the hydraulic cylinder against the bias of a return spring. In order to use the above-described door closer, the closer body a is fixed by screws k to the upper portion of a door j which is pivotally mounted, by a hinge i at its hanging side, to a vertical frame h, and the mounting plate e is fixed to an upper frame ℓ by one or more screws (not shown). In this manner, the piston is telescopically driven against the return spring by the piston drive shaft b being rotated as the door is opened, and the recovering force is accumulated in the return spring, and the door j is so mounted as to be automatically closed by the recovering force accumulated in the return spring. In the door closer described above, the closer body a and the mounting plate e are respectively mounted on the door j and the upper frame ℓ when the door is in its closed position. In this case, the door closer is so mounted that a recovering force of a certain degree is accumulated in the return spring even when the door is in its closed position, thus providing a form of latch. However, according to the conventional door closer, the closer body a, which must be mounted in the vicinity of the upper frame ℓ of the door j, is quite large. Therefore, in the case of a narrow mounting space (e.g. in the case of a glass door), sometimes it is impossible to mount the door closer. Further, in order to open the door fully in the direction of arrow m as shown in Figure 9, the piston drive shaft b must be rotated through a very large angle by the arm c. Accordingly, the internal structure of the door closer body a must be arranged to allow such a large angle of rotation: however this substantially restricts the degree of freedom for the design of the door closer body a. The angle α, formed between the arm c and the adjusting arm g, is indicated in Figure 9: as the door is opened wider, the angle α is gradually increased. When the door is fully opened, the angle α reaches its maximum value. When the door j is released from its fully open position, the door j is closed by the recovering force accumulated in the return spring. If the door is intended to be held in an open position, a suitable stopper mechanism must be provided. The conventional door closer further has the following disadvantage. The closer body a and the mounting plate e are fixed directly to the door j and the upper frame ℓ, when all components of the door closer are completely assembled. At this time, since arms c and g are rotatably biased in the direction of the arrow m in Fig. 9 by the recovering force accumulated in the return spring, the processes of mounting the closer body a and the mounting plate e are not easy, and occupy considerable time and labour. For any repair that may be needed to the door closer, not only the closer body a but also the mounting plate e must be removed. Therefore, when they are again mounted, problems arise such as alteration of the mounting positions because the old screw holes have become loose: exposure of the old screw holes is detrimental to the appearances of the door and the upper frame. US-A-2479835 discloses a door closer according to the preamble of claim 1 In accordance with the present invention, there is provided a door closer comprising a closer body having a body case which internally houses a damper mechanism, a door mounting arm projecting from said closer body and pivotally coupled, for rotation in a horizontal plane, to a door mounting bracket securable to a door, an adjusting arm coupled at one end to a rotary drive shaft of the damper and extending perpendicularly to the axis of said drive shaft and having its other end pivotally coupled, for horizontal rotation, to an upper frame mounting plate, the arms extending laterally with respect to the closer body, the door closer further comprising a return spring in which a recovering force is accumulated as the door is opened, the recovering force acting in the door-closing direction against a braking effect provided by the damper characterised in that the closer body and the respective arms are arranged symmetrically about a plane of symmetry which extends perpendicular to the axis of said drive shaft and the arms are coupled to the mounting bracket and mounting plate by removable step screws, so that the door closer can be inverted for use either on a door hinged along its left edge or on a door hinged along its right edge. Preferably the upper and lower surfaces of said door mounting and adjusting arms lie in common planes, or in equally-spaced planes, parallel to said plane of symmetry. Preferably the closer body has a speed-adjusting screw extending therethrough and accessible on the upper and lower surfaces of the closer body. Thus the closing speed of door closer can be adjusted from below, whichever way up the door closer is mounted. With the door closer of the present invention, the door requires only a small mounting portion, because only the relatively small bracket is secured to it, rather than the closer body. Also, the angle through which the drive shaft of the damper is rotated, when opening the door, is relatively small. Preferably the door closer is arranged so that the angle of intersection, between the two arms of the closer, reduces as the door moves to a fully open position: the recovering force of the return spring is thus decreased in this position, so that the door will remain open without the need for a separate stopper mechanism. The mounting bracket and mounting plate are detachably coupled to the respective arms of the door closer. The mounting bracket and mounting plate can therefore be easily and rapidly secured to the door and door frame respectively at predetermined positions, and then the door closer can be coupled to them. Subsequently, the door closer can be easily detached from the mounting bracket and mounting plate, for inspection, maintenance or repair of the door closer. Preferably the door mounting arm is coupled to the door mounting bracket so as to be rotatable in a horizontal plane. Preferably the other arm is adjustable in length and is also pivotable about a horizontal axis. Embodiments of this invention will now be described, by way of examples only and with reference to the accompanying drawings, in which: Fig. 1 is a front view of a door closer, although not in accordance with the invention, shown partly in an exploded state; Figs. 2, 3 and 4 are plan, front and bottom views respectively showing using various states of the door closer of Figure 1; Fig. 5 is an explanatory plan view showing a door closer of the type shown in Fig. 1, with the door open to different angles; Fig. 6 is a front view of a glass door to be provided with a door closer according to the present invention; Fig. 7a and 7b are two explanatory side views showing in section the two arms of respective modifications to the door closer of Figs 1 to 4, these two modifications being in accordance with this invention; Fig. 8 is a partial schematic side view of the closer body of the modified door closer of Fig 7a and 7b; and Figs. 9 and 10 are plan and front views respectively showing a conventional door closer. Figs 1 to 4 show a door closer, in accordance with a prefered embodiment of this invention. The door closer comprises a closer body 1 having a body case 2 formed in a vertical cylindrical shape, and filled with high viscosity fluid between a rotor (not shown) disposed therein and a stator (not shown) known per se. The case 2 is sealed by a cover plate, and a drive shaft for a damper (not shown) projects upwards through a central axial hole (not shown) of the cover plate and is fixed to a cylindrical cover 3 via a clamping screw 4. The closer body 1 has, as shown in Fig. 4, a speed adjusting screw 5 and a door opening angle adjusting screw 6, known per se. When the rotor (not shown) is rotated by a drive shaft, a damping effect is performed by the resistance force of the high viscosity fluid between the rotor and the stator. An arm 7 projects from the case 2 substantially perpendicular to the axial center of the case 2, and a mounting bracket 8 of substantially T shape is pivotally but detachably secured to the free end of the arm 7 via a step screw 9 which passes through a hole 7a in the arm 7 and is engaged in a threaded hole 8a of the bracket 8, so that the arm 7 is rotatable in a horizontal plane relative to the bracket 8. An adjustable arm 10 projects from the cover 3, and is pivotally connected to the cover 3 by a pin 11 as to be vertically upwardly or downwardly rotatable as indicated by arrows O and O' in Fig. 1. The adjustable arm 10 comprises an arm body 10a pivotally secured at a base end thereof to the cover 3, and a threaded lever 10b rotatable around an axis thereof and engaged in a longitudinal bore formed in the arm body 10a. The arm body 10a includes a rotatable threaded section 10c engaged with the threads on the lever 10b. When the adjusting section 10c is rotated the threaded lever 10b is longitudinally slid with respect to the arm body 10a, whereby the adjusting arm 10 is telescopically adjustable in length. In the example shown, a coupling bracket 12 is pivotally secured to the free end of the adjusting arm 10, i.e. to the free end of the threaded lever 10b, via a pin 13 as to be vertically rotatable as indicated by arrows ρ and ρ' shown in Fig. 1. An upper frame mounting plate 14 is pivotally but detachably secured to the free end of the adjusting arm 10 via a screw 15 which passes through a hole 12a of the coupling bracket and is engaged in a threaded hole 14a of the upper frame mounting plate 14. In the door closer constructed as described above, as shown in Figs. 2 and 3, the door mounting bracket 8 and the upper frame mounting plate 14 are fixed with screws (not shown) at the upper portion of the door 18 and the lower surface of an upper frame 19, at the hanging side of the door, i.e. the side which is pivotally secured via hinges e.g. 17 to a vertical frame 16. The door 18 is thus mounted for automatic closing. The door mounting bracket 8 and the upper frame mounting plate 14 are respectively secured to the door 18 and the upper frame 19, after they have been separated from the arm 7 and the adjustable arm 10, and then the arm 7 and the adjustable arm 10 are coupled to the bracket 8 and plate 14 via the step screws 9 and 15, thereby completing the process of mounting the door closer. Therefore, even if the door, e.g. a glass door 18A as shown in Figure 6, has a mounting portion of short height H, the door closer described above can be fitted easily, because the door mounting bracket 8 of small size is mounted to the door. As shown in Fig. 5, the angle ϑ1 (15°) formed between the arm 7 and the adjustable arm 10 when the door 18 is closed is small, but as the door is opened wider, the angle is sequentially increased as indicated by ϑ2, ϑ3 and ϑ4 (135°). Then when the door is opened beyond a predetermined angle, the angle between the two arms is decreased, for example to ϑ5 = about 80° in the fully open position of the door as shown in Fig. 5. As a result, the recovering force of the return spring, when the door is in its fully open position, is reduced from its maximum value: the door is maintained in its fully open position without a separate stopping mechanism. It will be appreciated that the return spring can be provided in the closer body 1 known per se, or provided in the adjusting arm 10. As understood from Fig. 5, the angle through which a conventional door 18 can be opened is large (180°), but since the angle between the arm 7 and the adjustable arm 10 of the door closer according to the present invention is relatively small, it is not necessary to rotate the drive shaft of the closer body 1 through a large angle. This increases the freedom for design of the door closer according to the present invention. In accordance with this invention, the door closer can be mounted in inverted senses, for use either on a door hinged along its left edge or on a door hinged along its right edge. Figs 7a and 7b show two alternative modifications to the door closer of Figs 1 to 4, to permit this inversion. Thus, in Fig 7a the upper surface 7a of the arm 7 and the upper surface 10d of the adjustable arm 10 are formed in the same plane as each other, and the lower surface 7b of the arm 7 and the lower surface 10e of the adjustable arm 10 are also formed in the same plane as each other. In the case of Fig. 7(b), there is a stepwise difference D1 between the plane of the upper surface 7a of the arm 7 and the plane of the upper surface 10d of the adjustable arm 10, substantially equal to a stepwise difference D2 between the plane of the lower surface 7b of the arm 7 and the plane of the lower surface 10e of the adjustable arm 10. As further schematically shown in Fig. 8, in the closer body 1, the adjusting end of a speed adjusting screw 5 is exposed at the lower surface of the case 2. When the speed adjusting screw 5 is adjustable turned, the damping force of the viscous fluid is controlled to adjust the door closing speed. The speed adjusting screw has an opposite end 5a which is exposed on the upper surface of the cover 3, and which can alternatively be used for adjustment purposes. The door closer described above can be used for either a left-hand hinged door or a right-hand hinged door. More specifically, when the door closer is desired to be used in an alternately hinged door, the door closer may be inverted upside down. In this case, with the arrangement of door closer described above, when the door closer is inverted upside down, the upper surface 7a and the lower surface 7b of the arm 7 as well as the upper surface 10d and the lower surface 10e of the adjustable arm 10 are merely inverted upside down, but the heights of the surfaces are invariable. Therefore, the door closer can be mounted without trouble by switching the door mounting bracket 8 of the arm 7 and the upper frame mounting plate 14 of the adjustable arm 10 to the upper sides of these arms after the door closer has been inverted. Further, when the adjusting end 5a of the speed adjusting screw 5 is turned by a screwdriver from below, the door closing speed of the door 18 can be simply adjusted even after the door closer is inverted upside down. It will be appreciated that even if the mounting portion of the door is narrow, there is no problem of mounting the door closer. Further, the freedom in design of the damper of the door closer is improved because the angle through which the drive shaft of the closer body turns is reduced. In addition, since the angle between the two arms of the closer in the fully open position of the door is reduced, as compared with conventional door closers, it is not necessary to provide a special stopper to maintain the door in the fully open position. The dimensional arrangements of the two arms of the door closer are such that the door closer can be inverted. Also, the speed adjusting screw is exposed on both the upper and lower surfaces of the closer body. Therefore, the door closer can be used for either a right-hand hinged door or a left-hand hinged door. In both cases, the door closing speed of the door can be adjusted from below. The door mounting bracket and the upper frame mounting plate can be removed from the respective arms of the door closer, and secured directly to the door and upper frame, and thereafter coupled to the door closer. Therefore, since the arm and the adjusting arm are held, rotated against the recovering force of the return spring, the door mounting bracket and the upper frame mounting plate can be simply coupled in the state that the recovering force is accumulated in the return spring to close the door and to latch it, the door closer can be easily and rapidly mounted reliably at a predetermined mounting position in a short period of time. In addition, if inspection, maintenance or repair is needed, the door closer alone can be removed, whilst the door mounting bracket and the upper frame mounting plate remain attached, by removing the arm and the adjusting arm respectively from the bracket and the plate. Further, since the remounting of the door closer is facilitated and there is no production of old, unused fixing holes, the external appearance of the door and the upper frame is not affected. Moreover, the misalignment of the mounting position of the door closer can be simply adjusted by adjusting the adjusting screw while the door closer remains attached as it is.

Claims: A door closer comprising a closer body (1) having a body case (2) which internally houses a damper mechanism, a door mounting arm (7) projecting from said closer body and pivotally coupled, for rotation in a horizontal plane, to a door mounting bracket (8) securable to a door (18), an adjusting arm (10) coupled at one end to a rotary drive shaft of the damper and extending perpendicularly to the axis of said drive shaft and having its other end pivotally coupled, for horizontal rotation, to an upper frame mounting plate (14), the arms (7,10) extending laterally with respect to the closer body (1), the door closer further comprising a return spring in which a recovering force is accumulated as the door is opened, the recovering force acting in the doorclosing direction against a braking effect provided by the damper, characterised in that the closer body (1) and the respective arms (7,10) are arranged symmetrically about a plane of symmetry which extends perpendicular to the axis of said drive shaft and the arms (7,10) are coupled to the mounting bracket (8) and mounting plate (14) by removable step screws (9,15), so that the door closer can be inverted for use either on a door hinged along its left edge or on a door hinged along its right edge. A door closer as claimed in claim 1, characterised in that the upper and lower surfaces (7a, 10d; 7b,10e) of said arms (7,10) lie in common planes, or in equally-spaced planes, parallel to said plane of symmetry. A door closer as claimed in claim 1 or 2, characterised in that the closer body (1) has a speed-adjusting screw (5) extending therethrough and accessible on the upper and lower surfaces of the closer body. A door closer as claimed in any preceding claim, characterised in that said one end of said adjusting arm (10) is pivotable about a horizontal axis (11). A door closer as claimed in any preceding claim, characterised in that said other end of said adjusting arm (10) is coupled by a coupling bracket (12) to said mounting plate (14), said adjusting arm (10) being pivotable about a horizontal axis (13) relative to said coupling bracket (12).

Inventors: OHSHIMA KAZUYOSHI SUGATSUNE IN, OHSHIMA, KAZUYOSHI, SUGATSUNE INDUSTRIAL CO. LTD.
Applicants: SUGATSUNE KOGYO, SUGATSUNE INDUSTRIAL CO., LTD.
Application year: 1991
Main classification: E05F3
IPC codes: E05F3