Patent Application
20090241287
This invention relates to a door closer, and in particular to a door closer known in the art as a concealed door closer which is mortised into the door leaf or its frame. The invention also relates to a fitting tool for such a door closer. The invention further relates to a kit of parts comprising a door closer and a fitting tool for the door closer.
Door closers are known in a wide variety of forms.
The most common type of door closer is known in the art as a face fixed overhead closer which includes a housing, incorporating a spring and a hydraulic damper arrangement, for fitting to the face of a door, on the pull side or the push side, and an articulated arm which is secured to the door frame. Alternatively, the housing can be mounted on the transom of the door frame on either the push side or pull side of the door, and the arm affixed to the door. The face fixed overhead closer can readily be made adjustable because the housing containing the spring and damper arrangement is at all times accessible. Also, the performance of the door closer with regard to the closing moment applied to the door and the closing time is acceptable.
However, this type of door closer suffers from a serious commercial disadvantage in that the design is not entirely acceptable for use in domestic premises for aesthetic reasons because both the housing and the arm are exposed to view. Also, the housing and the arm need to be fitted to exposed parts of the door face and frame, and this can be disadvantageous, particularly for antique, period or valuable doors. Finally, the exposed parts of the housing and the arm need to be cleaned regularly, which is inconvenient.
Concealed door closers are known which are adapted to be inserted into the hanging edge of the door leaf and are anchored to the frame edge by means of a linkage, for example a chain or a rigid arm. Such door closers incorporate a spring to provide a closing force for closing the door and a hydraulic damping arrangement which serves to regulate the rate of movement of the door in the direction of closure without restricting significantly the rate of movement in the direction of opening. Accordingly, the damping arrangement provides a steady controlled closing force for smooth closing of the door under the action of the spring, yet does not inhibit (or only minimally inhibits) opening of the door so that the opening moment required to be manually applied is low.
Typically, the operation of the damping arrangement is relieved or rendered ineffective just before the door reaches its closed position so that the resistance afforded by any latch or catch on the door will be overcome to ensure that the door closes fully and is latched. This may be achieved, in the case of a hydraulic damper, by means of a suitable fluid by-pass.
It is known to use an accumulator in the hydraulic damper to accommodate volume changes on opposite sides of a piston of the damping arrangement. This prevents inadvertent sudden movements of the piston due to the presence of air causing volumetric differences on opposite sides of the piston. The accumulator comprises a compressible foam body that is disposed on one side of the piston. In some constructions, the accumulator can inadvertently cause jamming of the movement of the piston. If this happens, the entire unit needs to be disassembled to unlock the piston. This is clearly highly inconvenient.
There is a need to provide a concealed door closer which does not inadvertently jam as a result of improper action by an accumulator incorporated within the hydraulic damper.
The concealed construction of known concealed door closer, where the housing containing the spring and damper arrangement is recessed and hidden within the door leaf, and only a face plate is exposed, inherently restricts both the versatility of the construction and the facility easily to install the concealed door closer and to adjust the operation of the unit after installation, in particular by a person other than a trained installer or engineer.
There is also a need to provide a concealed door closer which readily permits easy installation and adjustment of the operation of the door closer after installation, in particular the damping of the closure operation, and consequently the closure period.
The present invention aims to overcome problems in these known concealed door closers.
The present invention accordingly provides a door closer comprising:
This aspect of the present invention is predicated on the finding by the present inventor that inadvertent sealing of the accumulator against the piston in the compressed condition can cause jamming of the hydraulic damper of the concealed door closer. The inventor found that this problem can be solved by additionally providing a spacer for spacing an outer circumferential surface of the compressible foam body of the accumulator from an outer circumferential surface of the piston. This avoids inadvertent jamming of the piston caused by trapping of the compressible foam body between the piston and its cylinder,
In one embodiment, the spacer comprises a washer disposed between a rear surface of the piston and the compressible foam body. Preferably, the washer is annular and surrounds the piston shaft. Preferably, the washer has an outer cylindrical surface that is recessed radially inwardly relative to the outer cylindrical surface of the piston. Preferably, the diameter of the washer is smaller than that of the piston by a distance of at least 1 mm, more preferably from 1 to 5 mm.
In another embodiment, the spacer comprises an extension, on a rear surface of the piston, which extends towards the accumulator. Preferably, the extension is integral with the piston. Preferably, the extension is annular and surrounds the piston shaft. Preferably, the extension has an outer surface that is recessed radially inwardly relative to the outer cylindrical surface of the piston and has an end surface radially inwardly recessed relative to the outer cylindrical surface of the piston which contacts the accumulator. Preferably, a diameter of the end surface is smaller than that of the outer cylindrical surface of the piston by a distance of at least 1 mm, more preferably from 1 to 5 mm. The extension outer surface may be cylindrical, forming a stepped configuration on the rear surface of the piston. Alternatively, the extension outer surface may be frusto-conical.
The present invention also provides a door closer comprising: (a) a housing for fitting into a door, the housing having a mounting plate with an opening adjacent to a central bore of the housing; (b) a tension member extending longitudinally within the central bore of the housing and extending outwardly of the housing through the opening to define an end thereof for fitting to a door frame; (c) a movable body within the housing and adapted for longitudinal movement within the central bore, the movable body being connected to the tension member; (d) a spring within the housing and biasing the movable body in a first direction away from the mounting plate so as to urge the tension member inwardly of the housing in a door closing motion; and (e) a hydraulic damping assembly for damping the longitudinal movement of the movable body at least in the first direction, the hydraulic damping assembly being disposed within the central bore of the housing, wherein the hydraulic damping assembly comprises a piston, coupled to the housing by a piston shaft, and slidable in a fluid-filled chamber within the movable body, the piston divides the chamber into two compartments and the piston permits restricted movement of the fluid from one compartment to the other when the movable body is moved relative to the piston, and an accumulator comprising a compressible foam body disposed in the fluid-filled chamber so as to be compressible by the piston when the movable body has been moved by movement of the tension member out of the housing, the compressible foam body comprising an elongate body having a channel in an outer circumferential surface thereof extending along the length of the elongate body.
This aspect of the present invention is predicated on the finding by the present inventor that inadvertent sealing of the accumulator against the piston in the compressed condition can cause jamming of the hydraulic damper of the concealed door closer. The inventor found that this problem can be solved by shaping the accumulator to provide a vented channel away from the surface that contacts the piston, thereby preventing such sealing from occurring, and permitting flow of hydraulic fluid into the chamber portion that contains the accumulator.
Preferably, the compressible foam body at least partly surrounds the piston shaft, the piston shaft being received in an elongate bore of the compressible foam body.
Preferably, the channel and the bore are integral.
In one embodiment, the channel has radially directed sidewalls which are mutually spaced apart. The radially directed sidewalls may be mutually inclined at an angle of 40+/−5 degrees.
In another embodiment, the accumulator has an elongate chamber extending along the length of the elongate body, and an arcuate web portion at the outer circumferential surface of the elongate body that extends adjacent to the chamber, and the channel comprises an elongate slit that extends through the arcuate web portion from the outer circumferential surface to the chamber. Preferably, the arcuate web portion has been integrally moulded together with the remainder of the elongate body. More preferably, the slit has been formed by cutting through the arcuate web portion. The cut slit may extend radially from the outer circumferential surface to the chamber.
Preferably, the compressible foam body has a closed cell foam structure.
Preferably, the compressible foam body is composed of neoprene.
The present invention also provides a door closer comprising:
Preferably, the compressible foam body at least partly surrounds the piston shaft, the piston shaft being received in an elongate bore of the compressible foam body.
Preferably, the foam has a density of from 0.7 to 0.8 g/cm3.
Preferably, the foam is a closed cell expanded foam.
Preferably, the foam is composed of neoprene
Preferably, the door closer further comprises a spacer for spacing an outer circumferential surface of the compressible foam body from an outer circumferential surface of the piston.
Preferably, the compressible foam body comprises an elongate body having a channel in an outer circumferential surface thereof extending along the length of the elongate body.
In the door closers of the preferred embodiments of the present invention, the accumulator expands and contracts under the pressure of the fluid moving between the two sides of the piston head within the housing comprising a damper tube. This enables the door closer to have continuous damping from an opening angle of approximately 90 degrees down to closure of the door.
In contrast, if an accumulator is not provided in accordance with the present invention, the damping action is usually not effective until the door has partially closed from the 90 degree opening position and reached an opening angle about 45 degrees. The accumulator therefore provides effective damping of the door closing across its range of movement from a fully open position (i.e. 90 degrees of opening) to a fully closed position, ignoring any deliberate absence of damping immediately prior to final closure in the last few degrees of motion to enable the door motion to overcome any latching resistance on final closure. Such absence of damping causes the latching speed to increase to overcome any latch resistance on door closure.
Ideally the accumulator should not be compressed by the rear of the piston head moving towards the accumulator when the door is opened. In practice, designers of concealed door closers wish to have the smallest length of product to make installation less difficult. In addition, when the door closer is adjusted to reduce or eliminate the latch speed up action, by shifting the location of the piston shaft (e.g. the rear of the piston shaft is screwed outwardly relative to the housing), the piston head is brought even closer to the accumulator when the door is opened.
The inventor found that when using an accumulator inadvertent jamming of the door closer could occur. The various aspects of the present invention aim to avoid undesirable interactions between the accumulator and the piston head, and so avoid the jamming problem.
One modification made to the accumulator in accordance with an embodiment of the invention is to cut a longitudinal slit along the accumulator. This solved the jamming problem by preventing the accumulator creating a 360 degree seal.
However, in circumstances when the piston shaft was screwed outwardly to prevent the latching speed up, the inventor found that it was sometimes possible for the accumulator still to jam. It is believed that this is because the longitudinal split in the accumulator may no longer be fully effective under conditions where the accumulator is compressed by the rear of the piston head. Furthermore, the inventor found that further problems with the front cut edge of the accumulator jamming between the piston head and the damper tube inner wall under some circumstances.
The longitudinally cut accumulator does improve the operation of the door closer in a door closer design in which the accumulator is not compressed by the piston during operation.
To provide a modified door closer for use in circumstances in which the accumulator is compressed by the piston during operation, the inventor devised the provision of a spacer or alternatively a piston head of reduced diameter at the rear end thereof, to longitudinally space the accumulator from the piston and thereby prevent the front cut edge of the accumulator from inadvertently jamming between the piston head and the damper tube inner wall. Both of these designs worked successfully.
When a spacer or reduced diameter piston head was employed, the inventor found that there was no requirement to provide the accumulator with a longitudinal cut to achieve the result of avoiding jamming of the accumulator edge between the piston head and the damper tube inner wall. However, in practice it is believed that it would probably be best to have the combination of both a longitudinally cut accumulator and a spacer/shaped piston head.
The inventor then proceeded to investigate the effect of the properties of the closed cell expanded neoprene foam on the avoidance of jamming of the door closer. The inventor found that the density of the closed cell expanded neoprene foam affected the performance of the avoidance of jamming of the door closer. In particular, in accordance with this aspect of the invention it was found that a foam having a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3, did not encounter the jamming problem, even in the absence of any longitudinal cut and any spacer, unlike a lighter foam. There is a trade off between how well the accumulator performs in accommodating volumetric changes between the two chambers of the housing, which depends upon the compressibility of the foam and would favour a low density highly compressible foam, and how well the accumulator performs in avoiding inadvertent jamming, which would favour a higher density less compressible foam. In accordance with this aspect of the invention, this trade off is achieved by providing a foam, preferably a closed cell expanded foam, most typically of neoprene, having a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3,
It will be immediately apparent to a skilled person that the use of the compressible foam body comprising an elongate body having a channel in an outer circumferential surface thereof extending along the length of the elongate body can be optionally combined with the use of a spacer for spacing an outer circumferential surface of the compressible foam body from an outer circumferential surface of the piston to reduce further the risk of jamming of the piston caused by trapping of the compressible foam body between the piston and its cylinder, Also, the compressible foam body may, or may not, have the combination of both a channel in an outer circumferential surface thereof extending along the length of the elongate body and a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3, and/or comprise a closed cell expanded foam, most typically of neoprene.
The present invention also provides a fitting tool for a concealed door closer, the fitting tool comprising a U-shaped body with two parallel legs extending away from a base and with a central elongate linear slot, open at one end, between the two legs, the body having a first end face which is orthogonal to the through-direction of the slot and a second end face which is inclined at an acute angle both to the first end face and the through-direction of the slot.
This aspect of the present invention is predicated on the finding by the present inventor that the fitting tool can be shaped to have two opposite mutually inclined faces so that when fitted over the tension member of the concealed door closer, the door leaf and the door frame can be retained at a desired angular relationship in a partly open condition to permit the door fitting to be offered up to the door frame at the correct orientation, thereby permitting ready fixing, e.g. by screws, of the door fitting to the door frame.
Preferably, the first and second end faces are mutually inclined by an angle of from 15 to 45°, typically from 20 to 30°.
Preferably, the slot has parallel sidewalls defined by the legs.
Preferably, the body comprises a U-shaped central wall, orthogonal to the through-direction of the slot and first and second peripheral raised walls that respectively define the first and second end faces.
Preferably, the body is formed of an injection moulded plastics material.
The present invention further provides a kit of parts for fitting a concealed door closer, the kit comprising a door closer according to the present invention in combination with a fitting tool according to the present invention.
Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:—
Referring now to the accompanying drawings, a preferred embodiment of door closer 2 in accordance with the invention, as shown in
At the other end of the housing 4 a cylindrical end piece 16 is fitted into the housing 4 so as to close off the bore 6. The end piece 16 is secured in position, for example by crimping the end edge 18 of the housing 4 radially inwardly into an annular recess 19 in the end piece 16. A piston shaft, hereinafter referred to as a plunger shaft 20, is fitted to the end piece 16 and extends axially along a portion of the bore 6, typically about one half of the length of the bore 6. A reduced diameter portion 22 of the plunger shaft 20 extends through a hole 23 in the end piece 16, and a lock nut 24 is threaded onto an end of the plunger shaft 20 on the exposed face of the end piece 16. This arrangement permits the longitudinal position of the plunger shaft 20 in the bore 6 to be adjusted over a small distance after manufacture and assembly of the door closer 2 by turning the lock nut 24.
A hydraulic damper assembly 30 is mounted on the plunger shaft 20 for sliding movement therealong. The hydraulic damper assembly 30 includes an inner tube 32 which extends axially along a portion of the bore 6, typically about one half of the length of the bore 6. The inner tube 32 has an integral radially outwardly directed flange 34 at one end 36 thereof that is towards the end piece 16. The flange 34 and the mounting plate 8 define opposed bearing surfaces against which the opposed ends of a helical compression spring 38 are seated. The helical compression spring 38 surrounds the inner tube 32 and inner tube 32 is free to move along the bore 6 within the internal diameter of the helical compression spring 38 as the spring 38 is progressively compressed or expanded.
At the other end 40 of the inner tube 32 the end edge 42 is crimped radially inwardly to be mounted to a threaded connector 44 fitted within the inner tube 32, an O-ring seal 46 being disposed between the inner tube 32 and the threaded connector 44. A leaf spring assembly 48 is fitted to the threaded connector 44. The leaf spring assembly 48 includes a female threaded part 50 threadably fitted to a male threaded part of the threaded connector 44 to retain a pivot support 52 on the threaded connector 44. A tension member in the form of a leaf spring 54 is pivotally mounted to the pivot support 52 by a first pivot 56, for example a rivet. The leaf spring 54 extends trough a central hole 58 in the mounting plate 8. The other end of the leaf spring 54 is pivotally mounted to a door frame fitting 60 by a second pivot 62 in an end fitting 63 affixed to the leaf spring 54. The door frame fitting 60 has a flange 64 that is fixedly attached, e.g. by screws, to a door frame 66.
As the door is pushed open, the hinge action on the door causes the mounting plate 8 to be rotated away from the door frame fitting 58, and the leaf spring 54 is progressively pulled out of the housing 4. This causes the inner tube 32 to be pulled by the leaf spring 54 towards the mounting plate 8 (towards the right-hand direction in
The structure and operation of the hydraulic damping assembly will now be described.
The plunger shaft 20 is provided at its end thereof which is remote from the reduced diameter portion 22 fitted into the end piece 16 with a threaded end 70 threadably received in a blind hole of a piston head 72 which moves axially within the inner tube 32. The end of the inner tube 32 remote from the threaded connector 44 is fitted with a plug 74, and a piston seal 76 fitted adjacent the plug 74. The plug 74 and piston seal 76 slidably surround the plunger shaft 20. The piston seal 76 and threaded connector 44 define therebetween an elongate chamber 78 within which the piston head 72 can move longitudinally as a result of movement of the inner tube 32 relative to and longitudinally along the outer tube 4.
The piston seal 76 comprises an annular body of plastics or rubber material, typically nylon, and has an external diameter which is substantially the same as the internal diameter of the inner tube 32 so that when the piston seal 76 is received in the inner tube 32, there is a fluid tight seal between the outer circumferential surface of the piston seal 76 and the internal surface 80 of the inner tube 32. The internal circumferential surface of the piston seal 76 is slidably fitted on the outer circumferential surface of the plunger shaft 20 and is sealed relative thereto.
The piston head 72 moves within the chamber 78, and divides the chamber 78 into two first and second portions 82, 84. The first portion 82 is adjacent the piston seal 76 and the second portion 84 is adjacent the threaded connector 44. The outer diameter of the piston head 72 is slightly smaller than the inner diameter of the inner tube 32. The chamber 78 is filled with hydraulic fluid 86. When the piston head 72 moves longitudinally along the chamber 78, the hydraulic fluid 86 can flow over the outer circumferential surface of the piston head 72 in a slow and controlled manner. This damps the movement of the piston head 72, and thereby damps the action of the hydraulic spring 38 during opening and closing of the concealed door closer 2. At that end of the second portion 84 which is closed by the threaded connector 44, the inner diameter of the inner tube 32 is slightly enlarged as compared to the remainder of the inner tube 32, to provide a release portion 88. During the termination of the door closing operation, the enlarged diameter of the release portion 88 permits a greater rate of fluid flow over the piston head 72, and thereby reduced damping. This provides a greater closing force to ensure that the door is properly closed by overcoming any resistance from a door latch.
An accumulator 90 comprises an elongate foam member which is disposed in the first portion 82 of the chamber 78 adjacent the piston seal 76 and surrounds the plunger shaft 20. The accumulator 90 comprises a body of foamed plastics or rubber material, comprising a closed cell foam structure, such as neoprene. Typically, the accumulator 90 comprises a foam, most preferably a closed cell expanded foam, most typically of neoprene, having a density of greater than 0.6 g/cm3, more preferably from 0.6 to 0.7 g/cm3, Such a foam is available in commerce under Product Reference BEL CR 0.6 from Belpar Rubber Company Limited, St. Albans, Herts, UK. Alternatively, the accumulator 90 comprises a foam, most preferably a closed cell expanded foam, most typically of neoprene, having a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3, Such a foam is available in commerce under Product Reference BEL CR B75 from Belpar Rubber Company Limited, St. Albans, Herts, UK.
The accumulator 90 has a cross-sectional shape as shown in
When the door leaf 14 is fully opened, the piston seal 76 has moved (to the right in
By providing an elongate opening or channel 94 along the accumulator 90, this ensures that there is no possibility of the end 100 of the accumulator 90 inadvertently sealing against the adjacent surface 102 of the piston head 72 that faces the first portion 82 of the chamber 78. During the initial phase of the door closing operation, even if the end 100 of the accumulator 90 is pushed hard up against the adjacent surface 102 of the piston head 72, the inner tube 32 is free to move back under spring pressure from spring 38 and hydraulic fluid can flow into the first portion 82 of the chamber over the outer surface of the piston head 72 because on entering the first portion 82 the opening 94 acts to vent the hydraulic fluid away from the piston head 72, preventing a seal between the accumulator 90 and the piston head 72.
Alternatively, in accordance with another embodiment of the present invention, when the accumulator 90 comprises a foam, most preferably a closed cell expanded foam, most typically of neoprene, having a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3, the opening 94 may be omitted and the accumulator may comprise an simple annular cylinder having continuous outer and inner surfaces,
The modification of the accumulator of
Again, in accordance with another embodiment of the present invention, the accumulator 250 may comprise a foam, most preferably a closed cell expanded foam, most typically of neoprene, having a density of greater than 0.7 g/cm3, more preferably from 0.7 to 0.8 g/cm3.
Second and third embodiments of a door closer in accordance with the present invention are disclosed with reference to
In one embodiment, an 8 mm diameter washer 280 was used with a 12 mm diameter piston head 72. In another embodiment, having larger dimensions, the washer 280 had a diameter 1 mm less than that of the piston head 72.
In both of the embodiments of
In accordance with another aspect of the present invention, with reference to
In accordance with this additional aspect of the present invention, a fitting tool comprising a movement restrictor device 200 is provided. The restrictor device 200 comprises a body 202 having a generally U-shape, with two generally parallel legs 204, 206 extending away from a base 208 and with a central elongate linear slot 210, open at one end 212, between the two legs 204, 206. The slot 210 has parallel sidewalls 214,216 defined by the legs 204,206. The body 202 has a first end face 218 which is orthogonal to the through-direction of the slot 210 and a second end face 220 which is inclined at an acute angle both to the first end face 218 and the through-direction of the slot 210. Typically, the first and second end faces 218, 220 are mutually inclined by an angle of from 15 to 45°, typically from 20 to 30°. The body 202 is typically formed of an injection moulded plastics material, such as acetal.
The restrictor body 202 may be a solid body but more preferably, as shown in the illustrated embodiment, the body 202 comprises a central wall 222, orthogonal to the through-direction of the slot 210 and U-shaped. First and second peripheral raised walls 224,226 respectively define the first and second end faces 218, 220. One or more reinforcing ribs 228 may be provided extending between spaced parts of the raised walls 224,226 of one or both of the end faces 218, 220.
The central slot 210 of the restrictor device 200 has a width which is selected so as to be slightly larger than the thickness, typically in a horizontal direction, of a tension member such as, a leaf spring, of an associated concealed door closer, such as that of
As shown in
The restrictor device 200 holds the tension member 48 partially out of the door leaf 14 to enable the door frame fitting 60 to be offered up to the door frame 66 with the door leaf 14 being in a partly open configuration. The mutual angular inclination between the first and second end faces 218, 220 of the restrictor device 200 permits the door frame fitting 60 to be held at the required angle so that it can be placed flat against the door frame 66, with sufficient space between the door frame 66 and the door leaf 14 to enable access by a screwdriver to screw the screws 65 into the door frame 66. The angle of inclination between the two end faces 218,220 of the restrictor device 200 is selected to provide for the respective concealed door closer 2, with which the restrictor device 200 may be sold together with as a kit of parts, that the correct separation and angle of orientation of the door frame fitting 60 and the remainder of the concealed door closer 2 can be achieved during the installation operation. The provision of this restrictor device 200 greatly eases the installation of the concealed door closer 2, to enable ready fitting to the door frame 66.
When the opening direction of the door is in the opposite rotational direction to that shown in
It will be apparent to those skilled in the art that various modifications may be made to the disclosed embodiments without departing from the scope of the invention disclosed herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0606677.3 | Apr 2006 | GB | national |
| 0701263.6 | Jan 2007 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB07/01281 | 4/3/2007 | WO | 00 | 4/10/2009 |
