Door closers

Information

  • Patent Grant
  • 6625847
  • Patent Number
    6,625,847
  • Date Filed
    Monday, January 14, 2002
    22 years ago
  • Date Issued
    Tuesday, September 30, 2003
    21 years ago
Abstract
A door closer comprises an actuator assembly (20) adapted for fitting within the thickness of a door and an anchor member (10) adapted for fitting in a door frame in opposed relation to said edge face of the door. An operating member (30) is driven by spring means (45) and coupled to said anchor member (10) to draw the door towards the door frame. An adjustable fluid-filled damper (50) is coupled to said operating member (30) and arranged to provide variable regulation the rate of movement of the operating member under the force of said spring means (45). Resilient thrust means (85) are arranged to exert an increased driving force of said operating member (30) and adjustable control means (100) are provided whereby said thrust means (85) is operative to augment the driving force to said operating member (30) over a defined but variable part of said range of movement corresponding to movement of the door over the final part of its movement into its closed position.
Description




DESCRIPTION OF INVENTION




This invention concerns door closers of the kind comprising an actuator assembly intended for concealed fitting within the thickness of a door, and an anchor member for fixing to a door frame, and in which an operating member is coupled to said anchor member and is movable within the actuator assembly under the action of driving means, usually comprising one or more mechanical springs, and under the control of a uni-directionally operative fluid-filled damper which serves to regulate the rate of movement of the door in the direction of closure without significantly restricting the rate of movement of the door in the direction of opening.




It is desirable for the action of any damper in such a door closer to be adjustable so as to enable the rate of closure to be set to fall within a chosen range despite variations in the weight and other parameters of different doors with which the closer may be used, and for the closer to provide an augmented closing force as the door reaches its closed position in order to overcome resistance from any latch fitted to the door.




GB 2 044 840 A discloses such a door closer, which comprises an actuating assembly which is disposed in a housing that is located within the thickness of the door, having an operating member which is movable linearly by means of one or more coil springs, and coupled by a flexible linkage to the anchor member which is attached to the door frame.




EP 0 016 445 A discloses a door closer of this type in which adjustment of the final part of the closure movement of the door is achieved by means of an adjustment member associated with the anchor member which is attached to the door frame, the adjustment member being disposed behind a mounting plate of the anchor member at a variable spacing so as effectively to adjust the length of the coupling between the anchor member and the operating member in the actuator assembly. This arrangement does not make any provision for adjustment of the overall rate of closure, but only in the final closure position of the door relative to a final part of the travel of the piston in the door-closing direction, in which final part of the travel the action of the damper is rendered ineffective so as to provide for a locally increased rate of closure movement to overcome any resistance which may be offered by a door latch for example.




Although the rate of movement of the door as it approaches its position of closure is increased, there is no provision for adjusting the driving force applied to the door over the final part of closure movement, as relieving the effect of the damper does not increase the force applied by the driving springs, but only allows the door to accelerate in response to the driving force and the closing action then relies on the momentum of the moving door to overcome latch resistance. However, the acceleration achieved depends on many variable factors, including the weight of the door, wind loading on the door, and frictional resistance in die hinges and in the latch itself etc., and accordingly such designs do not entirely address the problem of overcoming resistance associated with a door latch.




DE 1 708 349 A discloses a door closer having a main spring which acts over the full range of movement of a rod which is coupled by a link to and anchor member, and a supplementary spring arranged end to end with the main spring and effective to increase the driving force applied to the rod over the final part of the closure stroke, but without provision for varying the point at which the supplementary spring becomes effective.




Accordingly, it is an object of the present invention to make provision for an augmented closure force to come into play as the door approaches its position of closure, as compared with the force applied throughout the remainder of the range of movement, whilst providing for adjustment of the operation to suit a wide range of requirements not achieved previously.




According to a first aspect of the invention we provide a door closer comprising in combination:




an anchor member for mounting on a door frame,




an actuator assembly for mounting within the thickness of a door which is hinged for movement between open and closed positions relative to said door frame,




an operating member coupled by an articulated link to said anchor member and mounted in said actuator assembly for a range of movement between a retracted position in which said anchor member is held immediately adjacent to said actuator assembly and an extended position in which said anchor member is held in spaced relation to said actuator assembly,




resilient driving means arranged to exert a driving force on said operating member in a manner such as to drive said operating member towards said retracted position and thereby draw said anchor member and said actuator assembly together such that, when installed, the door closer acts to draw the door into its closed position relative to the frame,




a damper connected to said operating member so as to control the rate of movement of the operating member in at least a direction towards said retracted position, said damper comprising a cylinder containing hydraulic fluid, a piston rod carrying a piston which divides the cylinder into two chambers, and flow-restricting means to limit the rate of flow of hydraulic fluid flow one of said chambers to the other at least in one direction of fluid flow in response to movement of said operating member towards said retracted position, an adjustable throttle which comprises two elements in combination, the flow restriction imposed on the hydraulic fluid by said throttle being variable by relative positional adjustment of said two throttle elements, and an adjustment member to enable one of said throttle elements to be positionally adjusted relative to the other so as to vary the flow restriction imposed on the hydraulic fluid by said throttle,




resilient thrust means arranged to exert an increased driving force on said operating member, and




control means whereby said thrust means is operative to apply said increased driving force to said operating member over a defined part of said range of movement as said operating member approaches said retracted position, corresponding to movement of the door over the final part of its movement into its closed position, and




an adjustment member operatively connected with said control means to vary the point in the range of movement of said operating member at which said resilient thrust means becomes operative to apply said increased driving force.




The control means preferably includes a detent means arranged to hold the thrust means in a stressed condition over the whole of the range of movement of the operating means apart from said defined part thereof.




In one arrangement, the thrust means may include a compression spring located within a guide member which is coupled to said operating means and slidable therewith along a fixed shaft, and the detent means may be mounted on a carrier member which abuts one end of the compression spring and is slidable on said fixed shaft and located on this said guide member for limited movement longitudinally thereof, the detent means being engagable in an internal recess formed within said guide member to hold the compression spring in a compressed condition, and being displaceable from said internal recess to release said compression spring at a predetermined position along said shaft.




The detent means may be displaceable from said position of engagement with said internal recess in said guide member into a position of engagement with an external recess formed in said shaft to hold said carrier member in a predetermined position on said shaft. Preferably, the detent means comprises a plurality of balls located in one or more transverse bores formed in the carrier member, and each of said balls is of a diameter greater than the radial spacing between said shaft and said guide member so that said balls are either held by said shaft in said internal recess in said guide member or by said guide member in said external recess in said shaft.




In a particularly preferred arrangement, the bores in which the balls are located are formed with a radially inner portion having a diameter such as to accept the ball with a slight clearance and a radially outer portion having a greater diameter, the two portions of the bore meeting at an internal shoulder which is located at a spacing from the shaft which is less than the radius of the ball. With this arrangement when the ball is held in the internal recess of the guide member, it has been found that the ball does not bind on the shaft, thereby allowing the shaft to move freely relative to the carrier.




In a preferred arrangement the cylinder of the damper is moveable relative to the actuator assembly and the piston is static, and the flow restriction means is incorporated into said piston and piston rod, and the adjustment member has an operating element which is accessible from one end of said piston rod.




The adjustment member may comprise a shaft located within an axial bore formed in said piston rod, with an external threaded formation engaging an internal threaded formation in the bore of the piston rod whereby rotation of the shaft varies its axial position within said bore. The shaft may be provided at one end with a needle formation which comprises one of said throttle elements to cooperate with an orifice defined by the other of said elements, and at its other end with a head formation whereby the shaft may be rotated.




The thrust means may comprise one or more spring elements having a higher rate than the resilient driving means. Preferably both the driving means and the thrust means comprise one or more coiled compression springs, but other arrangements are possible. For example the thrust means may comprise one or more stacks of Belville washers, and the driving means could comprise gas-springs.




In a particularly convenient arrangement, said thrust means and said driving means each comprise two elements disposed symmetrically relative to a single damper means, but other arrangements are possible.











These and other features of the invention will now be described by way of example with reference to the accompanying drawings wherein:





FIGS. 1A and 1B

are partially sectioned side views of one embodiment of door closer to which the invention is applied, comprising an anchor assembly and an actuator assembly, and shown with these assemblies respectively in the “door closed” condition and in the “door open” condition;





FIG. 2

is a front end view of the actuator assembly in the direction of arrow II of

FIG. 1B

,





FIG. 3

is a horizontal section on the line III—III of

FIG. 1B

,





FIG. 4

is a composite section substantially on the line IV—IV of

FIGS. 1A and 1B

,





FIG. 5

is a longitudinal section through an adjustable damper assembly incorporated in the closer.





FIG. 6

is a longitudinal section on the line VI—VI of

FIG. 1B

showing the construction of thrust means in a first, compressed condition,





FIG. 7

is a longitudinal section on the line VII—VII of

FIG. 1A

showing the construction of thrust means in a second, uncompressed condition,





FIG. 8

is a transverse section on an enlarged scale on the line VIII—VIII of

FIG. 6

,





FIG. 9

is a section on the line IX—IX of

FIG. 8

,





FIG. 10

is a graph relating the closure force obtained from a closer in accordance with the invention to the angle of opening, and





FIG. 11

is a graph relating the door closure speed to door closing time.











The door closer as illustrated in

FIGS. 1

to


9


comprises an anchor assembly


10


which is adapted for mounting a door frame at a vertical edge thereof facing the hinged edge of a door hingedly carried by the frame, and an actuator assembly


20


which is adapted for mounting within the thickness of the door.




The anchor assembly


10


comprises a mounting plate


11


and an adjustment plate


12


which is spaced from the mounting plate on the side thereof remote from the door by an adjustable distance. An adjusting screw


13


is engaged in a threaded hole


14


formed in the adjustment plate


12


and a slotted head portion


15


of the screw bears against the mounting plate


12


and is accessible through a central hole


16


formed in the mounting plate


11


. It will be understood that by rotation of the screw


13


the spacing of the adjustment plate


12


and mounting plate


11


can be varied for the purpose hereinafter described.




The mounting plate


11


is also formed with a pair of apertures


17


near the ends thereof and the adjustment plate


12


is formed with a pair of apertures


18


aligned with the apertures


17


whereby the adjustment plate


12


is coupled to an operating member


30


of the actuator assembly


20


as hereinafter described.




The actuator assembly


20


is so dimensioned as to be suitable for fitting within the thickness of the door and for this purpose is provided with a mounting member


21


having bosses near the outer ends thereof formed with apertures


22


which align with the apertures


17


of the anchor assembly mounting plate


11


, a central boss formed with a bore


23


, and intermediate bosses formed with a respective bore


24


having a reduced diameter portion intermediate the ends thereof, as shown clearly in FIG.


1


A.




The apertures


22


locate therein fixed sleeves


25


which are provided with an external flange


26


abutting against the end face of the boss around aperture


22


. The central bore


23


is partially threaded to receive a threaded end portion of a rod


27


, and the intermediate bores


24


each locate one end of a respective shaft


28


secured therein by means of screws as shown. The sleeves


25


, rod


27


and shaft


28


extend parallel to one another and the ends of the shafts


28


furthest from the mounting member


21


are supported by a transverse stop plate


29


which is secured to the free end of the rod


27


by means of a screw or the like.




The actuator assembly


20


further includes an operating member


30


, as above-mentioned, which is carried by the mounting member


21


and guided for longitudinal movement by the sleeves


25


, rod


27


and shafts


28


. The operating member


30


includes a pair of parallel shafts


31


which are located in the sleeves


25


, and each has at one end a pivotal connection


32


to a respective rigid link


33


which is disposed within the associated sleeve


25


when the closer is in the “door closed” condition as shown in FIG.


1


A. The links


33


have a pivotal connection


34


with respective headed studs


19


which extend through the apertures


17


in the mounting plate


11


and through apertures


18


of the adjustment plate


12


of the anchor assembly


10


. The links thus form an articulated connection between the shafts


31


and the anchor assembly


10


.




The operating member


30


further includes, at the other end of the shafts


31


, a cross-head


35


by which the shafts


31


are interconnected. The cross-head


35


is formed with outermost bosses with apertures


36


through which the shafts


31


extend and the cross-head is secured to the shafts


31


by means of pins (not shown). As seen most clearly in

FIGS. 5

,


6


and


7


, the cross-head


35


is also formed with a central boss and a central aperture


37


in which the end of the rod


27


is located with a sealing ring, and a pair of intermediate bosses with apertures


38


through which the shafts


28


pass with clearance.




The operating member


30


is movable inwardly towards a retracted or “door closed” position as shown in

FIG. 1A

under the force of driving springs


45


, which, in the illustrated embodiment, compromise coil springs extending between the cross-head


35


and the flanges


26


on the fixed sleeves


25


. In addition, floating sleeves


40


are located on each of the shafts


31


and carry a respective clip


41


which engages between turns of the respective spring


45


. Alternatively, separate springs may be provided on opposite sides of the clip


41


.




As will be evident, the compression springs


45


act on the cross-head


35


to drive the latter inwardly of the actuator assembly


20


to the retracted position and to draw the shafts


31


and the associated links


33


inwardly so as to bring the mounting plate


11


of the anchor assembly


10


up to the mounting member


21


of the actuator assembly, in the manner illustrated in

FIG. 1A

, thereby holding the door in its closed position.




When the door is opened, as shown in

FIGS. 1B and 3

, the shafts


31


and cross-head


35


are drawn outwardly, thereby causing the springs


45


to be compressed, abutment of the floating sleeves


40


against the fixed sleeves


25


limiting the outward travel of the cross-head


35


at an extended or “door open” position. When the door is released, the coil springs


45


act to return the cross-head


35


and the shafts


31


to their starting positions, thereby bringing the door back to its closed position relative to the frame.




The actuator assembly


20


further includes a damper assembly


50


to regulate the rate of closure of the door under the action of the springs


45


.




The damper assembly


50


as shown in

FIG. 5

comprises a fixed piston


51


formed on the rod


27


at an intermediate position, and a cylinder


52


carried by the cross-head


35


and containing hydraulic fluid. The cylinder


52


is located at one end, with an appropriate seal, in a recess


53


formed in a boss at the centre of the cross-head


35


, and is closed at its other end by a plug


54


, which is retained by means of a clip


55


in the mouth of the cylinder. The plug


54


is formed with a bore


56


through which the piston rod


27


passes. Appropriate sealing rings


57


,


58


are arranged to engage sealingly with the exterior surface of the rod


27


and with the interior surface of the cylinder


52


as shown.




In the illustrated embodiment the fixed piston rod


27


is assembled from first and second rod sections


59


,


60


. The first rod section


59


is formed with a radial enlargement having a peripheral groove


61


for a sealing ring


62


which engages with the interior face of the cylinder


52


so that the enlargement serves as the piston


51


. The second rod section


60


includes a widened end portion


63


which has in internal bore


64


to receive an end portion of the first rod section


59


.




The piston


51


divides the cylinder


52


into inner and outer compartments


65


,


66


and fluid passageways as hereinafter described are formed in the piston


51


and the rod


27


to enable hydraulic fluid to pass from one compartment of the cylinder to the other in a controlled manner.




Axial passageways


67


extend directly between opposite faces of the piston


51


. The widened end portion


63


of the second rod section


60


has an end face


68


which is spaced axially from the piston


51


, and a flexible seal


69


is disposed between the end face


68


and the piston


51


. The flexible seal


69


is moveable within the gap between the end face


68


and the piston


51


in response to fluid pressure so to close or open the axial passageways


67


.




The flexible seal


69


lifts from the ends of the axial passageways


67


in response to opening movement of the door, so that fluid may flow freely from the inner compartment


65


to the outer compartment


66


and the door may be opened freely. However, in response to movement of the door towards its closed position the flexible seal


69


covers the ends of the axial passageways


67


in such a manner as to prevent liquid flowing directly from the outer compartment


66


to the inner compartment


65


through the axial passageways


67


.




To enable fluid to flow from the outer compartment


66


to the inner compartment


65


, radial passageways


70


are formed in the first rod section


59


adjacent to the face of the piston which is presented towards the cross-head


35


to communicate with a central bore


71


which terminates, at the end of the first rod section


59


which is presented towards the mounting member


21


, in a throttling orifice


72


. Further radial passageways


73


extend from the outer face of the widened end portion


63


of the outer rod portion


60


to a central chamber


74


formed at the inner end of an axial bore


75


which extends through the second rod section


60


to its outer end where it is received in the central bore


23


of the mounting member


21


.




The axial bore


75


includes a widened end portion


76


adjacent to the central chamber


74


, and an internally threaded portion


77


adjacent to the widened end portion


76


. The widened end portion


76


receives an adjustable throttle member


80


which includes an externally threaded shank portion


81


received within the internally threaded portion


77


of the bore


75


, and a needle port ion


82


which co-operates with the orifice


72


. The shank portion


81


of the throttle member


80


is formed with slot


83


to receive the end of a screwdriver blade which can be inserted along the bore


75


, to enable the throttle member


80


to be rotated to adjust the axial position of the needle portion


82


relative to the throttle orifice


72


to provide a variable restriction.




When the passageways


67


are closed by the flexible seal


69


, communication between the two compartments of the cylinder


52


is only possible through passageways


70


,


71


and


73


, and the throttling orifice


72


. In this way, the orifice


72


serves as an adjustable throttle to regulate the flow of fluid from the outer compartment


66


to the inner compartment


65


as the cross-head


35


is driven inwardly of the actuator assembly by the compression springs


45


. The rate at which the door is closed under the force of the springs


45


can thus be adjusted, and it is particularly to be noted that such regulation is effective throughout the entire range of movement of the operating member


30


from the extended position shown in

FIG. 1B

to the retracted position shown in FIG.


1


A. However, on the reverse stroke, when the door is being opened, the flexible seal


69


is able to lift from the ends of the axial passageways


67


and allow relatively unrestricted flow of fluid between the two compartments.




The actuator assembly


20


further includes a pair of thrust assemblies


85


mounted on the shafts


28


disposed between the respective driving springs


45


and the damper assembly


50


.




As can best be seen from

FIGS. 6 and 7

an innermost end portion


86


of each shaft


28


is of slightly greater diameter than the outermost end portion


87


so as to form an outwardly facing shoulder


88


at the junction between the two portions. A groove


89


is formed around the narrower portion


87


of each shaft


28


at a predetermined spacing from the shoulder


88


.




The thrust assemblies


85


each include a thrust spring


90


located on the respective shaft


28


and within a cylinder


91


concentric with the shaft. Each cylinder


91


is fixed in a recess


92


formed in the intermediate boss of the cross-head


35


, and serves as a guide for the thrust spring


90


. The thrust springs


90


are strong compression springs having a rate greater than that of the coil springs


45


.




An internally widened end portion


93


of each cylinder


91


forms an outwardly facing shoulder


94


, and internally the widened end portion


93


is formed with a circumferential groove


95


at a predetermined spacing from the shoulder


94


. The arrangement is such that when the cross-head


35


abuts the stop plate


29


as shown in

FIG. 7

, the groove


95


in the cylinder


91


is longitudinally offset relative to the groove


89


formed in the shaft


28


, so as to be somewhat further from the mounting member


21


. The widened end portion


93


of each cylinder


90


is fitted with a retaining clip


96


.




A control mechanism


100


is provided whereby said thrust springs


90


are employed to augment the force of the driving springs


45


. The control mechanism includes in each cylinder


91


a carrier block


101


which is held in contact with the retaining clip


96


by engagement with the thrust spring


90


. As best seen in

FIGS. 8 and 9

, the carrier block


101


is formed with a central bore


102


whereby it is slidable on the narrower portion


87


of the shaft


28


. The carrier block


101


is also formed with two intersecting transverse bores


103


,


104


which contain four balls


105


in the respective radial arms thereof. The transverse bores


103


,


104


, balls


105


and grooves


89


and


95


are so dimensioned that the balls


105


may be displaced radially to seat in either the groove


89


formed on the shaft


28


, or in the groove


95


formed in the cylinder


91


.




As can be seen from

FIG. 7

, when the door closer is in its closed condition the balls


105


are located in the groove


89


formed in the shaft


28


, and they are held in this position by engagement of the balls


105


with the interior surface of the widened end portion


93


of the associated cylinder


91


at a point spaced outwardly from the groove


95


by a small distance. The balls thus act as a detent means which holds the carrier block


101


in a pre-determined position on the shaft


28


, in which position the carrier block is spaced from the shoulder


94


in the cylinder


91


and the thrust spring


90


is in a relatively extended condition.




As the door is opened, the cross-head


35


and cylinders


91


move outwardly (i.e. to the left as shown in

FIG. 7

) so that the thrust springs


90


are immediately compressed against the carrier blocks


101


, which are held in fixed positions on the shafts


28


by engagement of the balls


105


in the grooves


89


, since the balls


105


are held against outward displacement by engagement with the interior surface of the cylinders


91


.




However, the groove


95


in each cylinder


91


is so disposed relative to the shoulder


94


that when the shoulder


94


comes into engagement with the stationary carrier block


101


, the groove


95


is then in alignment with the transverse bores


103


,


104


in the carrier block


101


, thereby allowing balls


105


to move radially outwardly. Continued outward movement of the cylinder


91


can thus drive the carrier block


101


outwardly along the shaft


28


, and displace the balls


105


radially outwardly into the grooves


95


as shown in FIG.


6


.




As outward movement of the cylinder


91


continues, the balls


105


are held within the groove


95


by engagement with the exterior surface of the outermost portion


87


of the shaft


28


. At this time, the carrier block


101


is held in a fixed position relative to the cylinder


91


(i.e. against the shoulder


94


), by the detent action of the balls


105


in the grooves


95


, thereby holding the thrust springs


90


in a compressed condition, as shown in FIG.


6


.




As shown most clearly in

FIGS. 7 and 8

, the radial bores


103


,


104


are each of stepped form, with an internal shoulder


106


at the junction between an inner portion


107


, which is of such a diameter as to accommodate the ball


105


with minimum clearance, and a somewhat widened outer portion


108


. The shoulder


106


of each bore is spaced from the surface of the shaft


28


by a distance which is slightly less than the radius of the ball


105


. The effect of this is that the shoulder


106


assists in retaining the ball in the groove


95


while relieving the pressure exerted by the ball on the shaft


28


. This facilitates movement of the carrier blocks


101


along the shafts


28


by reducing friction, since the balls


105


are pressed laterally against the shoulder


106


as shown in

FIG. 9

in such a manner as to apply a radially outwardly directed force to the ball, thereby holding it in the groove


95


while at the same time relieving the pressure exerted by the ball on the shaft


28


.




In operation, the thrust springs


90


are initially in a relatively unstressed condition as shown in

FIG. 7

while the door is closed and are compressed during the initial stages of the opening movement of the door through a distance corresponding to movement of the shoulders


94


within the cylinders


90


into engagement with the carrier blocks


101


while the carrier blocks are held in fixed positions on the shafts


28


. The thrust springs


90


are then held in that compressed condition, as shown in

FIG. 6

, throughout the remainder of the movement while the carrier blocks


101


are held in fixed positions in the cylinders


91


and travel with the cylinders, along the shafts


28


.




When the door closes subsequently under the action of compression springs


45


, the carrier blocks


101


are initially retained in their fixed positions within the cylinders


91


, since the balls


105


continue to be held within the grooves


95


by the shaft


28


and the thrust springs


90


are maintained in their stressed condition. But when the transverse bores


103


,


104


of the carrier blocks


101


again come into register with the grooves


89


formed in the shafts


28


, some way before the door reaches its closed position, at this point the balls


105


are free to move radially inwardly into the grooves


89


, thereby moving out of the grooves


95


formed in the cylinders


91


, and releasing the cylinders relative to the carrier blocks


101


. The carrier blocks


101


are then held in a fixed position relative to the shafts


28


, and the thrust springs


90


, acting on the now fixed carrier blocks


101


exert an augmented driving force on the cross-head


35


over the final part of its range of movement as the shoulders


94


of the cylinders


91


move away from the carrier blocks


101


as shown in FIG.


7


.




The adjustment plate


12


enables the point at which the thrust springs


90


come into operation to be varied. Adjustment of the adjustment plate


12


relative to the mounting plate


11


of the anchor assembly


10


alters the angular position of the door at which the balls


105


become aligned with the grooves


89


in the shafts


28


by varying the spacing between the mounting plate


11


of the anchor assembly


10


and the cross-head


35


of the operating member


30


. In this way the fixed position of the grooves


98


corresponds to any selected position of the mounting plate


11


within a predetermined range of positions. Typically, the range of adjustment may be between 0 and about 15° of opening. Thus at one extreme, the thrust springs may be rendered ineffective if desired, whilst the range of angular movement over which they are effective, when required, can be set at up to 15° or thereabouts according to the precise geometry adopted.




This is illustrated in

FIG. 10

, in which the total force (F) exerted on the operating member


30


is shown relative to the angle of opening (α). As can be seen from the maximum angle of opening (α


max


) to an adjustable angle (α


x


) the force is at an ideally constant value (F


S1


). At the point (α


x


) the force increases sharply to an augmented value (F


S2


) and ideally remains at that value throughout the remainder of the range of movement to the position of closure represented by (α


0


). The angle (α


x


) may be varied between zero (α


0


) and typically about 15° as previously described.




In practice, the damper assembly


50


is, however, operative over the entire range of movement of the operating member


30


up to the “door closed” position to provide a controlled and adjustable rate of closure and thus a variable time to closure from any initial angle of opening as previously described, and the forces exerted by the closer are not constant during each part of the closing movement as illustrated in FIG.


10


. Thus in a typical embodiment with the main springs


45


fully compressed the closing force is initially 1040 Newtons (234 lbs.) whereas at approximately 16° opening angle and just prior to engagement of the thrust springs


92


the force is 612 Newtons (137 lbs.) whilst at 14° when the thrust springs have come into operation the force is increased to a total of 1308 Newtons (294 lbs.) of which 718 Newtons arises from the thrust springs.




The effect of the damper is illustrated in

FIG. 11

which shows the door closing speed (V) plotted against door closing time (T) from the position of maximum opening to closure, with minimum and maximum damping and an indication of the variable range of operation of the thrust springs.




With the damping set at minimum, and the action of the thrust springs set at maximum, the door speed follows the upper solid line curve (M), from which it can be seen that at time= to the door accelerates from rest to a uniform velocity V


1


and at time=t


1a


the thrust springs become effective with the result that the door speed increases to a higher velocity V


2


until at point A the door reaches its position of closure at time=t


2a


.




If the damping is set at the maximum value, the door speed follows the lower solid line curve (N) to a lower velocity V


3


and the thrust springs become effective at time=t


1b


following which the door speed increases to a value V


4


until at point B the door reaches its position of closure at time t=t


2b


.




However, if the thrust springs are rendered inoperative by appropriate adjustment of the plate


12


, when the damping is set at minimum the door continues to close at velocity V


1


as indicated by the broken line M′ until at point A′ it reaches its position of closure at time t=t


1c


whereas when the damping is set at maximum the door continues at velocity V


3


as indicated by broken line N′ until at point B′ it reaches its position of closure at time=t


2c


.




The shaded area bounded by points A, A′, B and B′ represents the envelope within which the closure time can be varied by the combined adjustments available by means of the adjustment plate


11


and the adjustable throttle incorporated in the damper assembly


50


.




Thus at all times during the closing action, the rate of movement of the door is controlled by the damper assembly


50


but, as illustrated in

FIG. 10

, the closing force applied by the driving springs


45


can be substantially augmented from F


S1


to F


S2


by the thrust springs


90


over a variable final part (α=α


x


to α


0


) of the closure movement, thus overcoming any resistance to closure which may be imposed by a latching mechanism operating between the door and door frame, but without the potentially excessive “snap action” associated with previous door closures of the kind in which the flow restriction imposed by the damper assembly is relieved during the final part of the closure movement. However, adjustment of the damper makes it possible to provide a controlled degree of snap action, when the flow restriction is set to a minimum, or a “soft” action, when die flow restriction is set to a maximum, or anything in between.




Adjustment of the position of the adjustment plate


12


of the anchor assembly


10


varies the effective length of the connection between the cross-head


35


and the anchor assembly, and can thus also enable the action of the thrust springs


90


to cut in at the correct point despite variations in the width of the gap between the inner edge of the door and the door flame in different installations.




The door closer as above described is fully adjustable with respect to the selected range of angular movement over which the augmented closure force is applied, and with respect to the degree of damping applied, whilst being particularly compact so that it can be installed in a door without compromising the fire resistance of the door.




The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.



Claims
  • 1. A door closer comprising in combination:an anchor member (10) for mounting on a door frame, an actuator assembly (20) for mounting within the thickness of a door which is hinged for movement between open and closed positions relative to said door frame, an operating member (30) coupled by an articulated link (33) to said anchor member (10) and mounted in said actuator assembly (20) for a range of movement between a retracted position in which said anchor member (10) is held immediately adjacent to said actuator assembly (30) and an extended position in which said anchor member (10) is held in spaced relation to said actuator assembly (30), resilient driving means (45) arranged to exert a driving force on said operating member (30) in a manner such as to drive said operating member towards said retracted position and thereby draw said anchor member (10) and said actuator assembly (20) together such that, when installed, the door closer acts to draw the door into its closed position relative to the frame, a damper (50) connected to said operating member so as to control the rate of movement of the operating member (30) in at least a direction towards said retracted position, said damper comprising a cylinder (52) containing hydraulic fluid, a piston rod (27) carrying a piston (51) which divides the cylinder (52) into two chambers (65, 66), and flow-restricting means (70-83) to limit the rate of flow of hydraulic fluid from one of said chambers to the other at least in one direction of fluid flow in response to movement of said operating member towards said retracted position, an adjustable throttle, which comprises two elements (72, 82) in combination, the flow restriction imposed on the hydraulic fluid by said throttle being variable by relative positional adjustment of said two throttle elements, and an adjustment member (80) to enable one of said throttle elements to be positionally adjusted relative to the other so as to vary the flow restriction imposed on the hydraulic fluid by said throttle, resilient thrust means (85) arranged to exert an increased driving force on said operating member (30), control means (100) whereby said thrust means (85) is operative to apply said increased driving force to said operating member (30) over a defined part of said range of movement as said operating member (30) approaches said retracted position, corresponding to movement of the door over the final part of its movement into its closed position, and an adjustment member (12) operatively connected with said control means (100) to vary the point in the range of movement of said operating member at which said resilient thrust means (85) becomes operative to apply said increased driving force.
  • 2. A door closer according to claim 1 wherein said control means (100) includes detent means (105) arranged to hold said thrust means (85) in a stressed condition over the whole of the range of movement of the operating member (30) apart from said defined part of said range.
  • 3. A door closer according to claim 2 wherein said thrust means (85) includes a compression spring (90) located within a guide member (91) which is coupled to said operating member (30) and slidable therewith along a fixed shaft (28), and said detent means (105) is provided on a carrier member (101) which is retained within said guide member (91) to abut one end of said compression spring (90) and is slidable on said fixed shaft (28) and located within said guide member (91) for limited movement longitudinally thereof, the detent means (105) being engagable in an internal recess (95) formed within said guide member (91) to hold the compression spring (90) in a compressed condition, and being displaceable from a position of engagement with said internal recess (95) to release said compression spring (90) at a predetermined position along said shaft (28) so as to apply said increased driving force to said operating member (30).
  • 4. A door closer according to claim 3 wherein said detent means (105) is displaceable from said position of engagement with said internal recess (95) in said guide member (91) into a position of engagement with an external recess (89) formed in said shaft (28) to hold said carrier member (101) in a predetermined position on said shaft (28).
  • 5. A door closer according to claim 4 wherein said detent means comprises a plurality of balls (105) located in one or more transverse bores (103, 104) formed in said carrier member (101).
  • 6. A door closer according to claim 5 wherein each of said balls (105) is of a diameter greater than the radial spacing between an exterior face of said shaft (28) and an interior face of said guide member (91) so that said balls (105) are either held by said shaft (28) in said internal recess (95) formed in said guide member (91) or by said guide member (91) in said external recess (89) formed in said shaft (28).
  • 7. A door closer according to claim 6 wherein the bores (103, 104) in which the balls (105) are located are formed with a radially innermost portion (107) having a diameter such as to accept the ball with a slight clearance and a radially outermost portion (108) having a greater diameter, the two portions meeting at an internal shoulder (106) disposed at a spacing from the shaft (28) which is less than the radius of the ball (105).
  • 8. A door closer according to claim 7 wherein said cylinder (52) of said damper (50) is moveable relative to said actuator assembly (20) and is coupled to said operating member (30), and said piston (51) is static.
  • 9. A door closer according to claim 8 wherein said flow-restricting means (70-83) is incorporated into said piston (51) and piston rod (27), and said adjustment member (80) has an operating element (83) which is accessible from one end of said piston rod (27).
  • 10. A door closer according to claim 9 wherein said adjustment member (80) comprises a shaft located within an axial bore (75) formed in said piston rod (27), with an external threaded formation (81) engaging an internal threaded formation (77) in the bore of the piston rod whereby rotation of the adjustment member (80) varies its axial position within said bore (75).
  • 11. A door closer according to claim 10 wherein said adjustment member (80) is provided at one end with a needle formation (82) which comprises one of said throttle elements to co-operate with an orifice (72) defined by the other of said elements, and at its other end with a head formation (83) whereby the adjustment member (80) may be rotated.
  • 12. A door closer according to claim 7 wherein said thrust means (85) includes one or more spring elements (90) having a higher rate than said resilient driving means (45).
  • 13. A door closer according to claim 12 wherein both said driving means (45) and said thrust means (85) comprise one or more coiled compression springs (45, 90).
  • 14. A door closer according to claim 13 wherein said thrust means (85) and said driving means (45) each comprise two spring elements (45,45: 90,90) which extend in side by side parallel relationship and disposed symmetrically relative to said damper means (50).
  • 15. A door closer according to claim 14 wherein said thrust means (85) are disposed between said driving means (45) and said damper means (50).
Priority Claims (1)
Number Date Country Kind
9904845 Mar 1999 GB
PCT Information
Filing Document Filing Date Country Kind
PCT/GB00/00717 WO 00
Publishing Document Publishing Date Country Kind
WO00/52291 9/8/2000 WO A
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Number Name Date Kind
1239510 Nordquist Sep 1917 A
2437192 Glanz Mar 1948 A
2602662 Kintzinger Jul 1952 A
3372427 Koivusalo Mar 1968 A
3449788 Wake Jun 1969 A
3887961 Saajos Jun 1975 A
4102006 Jenkins Jul 1978 A
4317254 Chaddock Mar 1982 A
4760621 Stromquist Aug 1988 A
5016317 Hung May 1991 A
5706551 Jeynes et al. Jan 1998 A
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Number Date Country
17 08 349 May 1971 DE
33 23 063 Jan 1985 DE
4005386 Aug 1991 DE
195 13 434 Oct 1996 DE
297 04 103 Jul 1998 DE
0 0616 445 Oct 1980 EP
0332426 Sep 1989 EP
2 566 827 Jan 1986 FR
1497220 Jan 1978 GB
2167121 May 1986 GB
WO 9605397 Feb 1996 WO