GB2241738A - A door closer for a door - Google Patents

Abstract

A door closer (37) for a door (38), which door closer (37) comprises a spring (11) which flexes as the door (38) opens and which returns the door (38) to its closed position after use, braking means (15, 16, 17; 18,19, 20, 21), a unidirectional clutch (26) which releases the braking means when the door is opening and which engages the braking means as the door returns to its dosed position, and release means (28, 29) for releasing the braking means towards the end of the travel of the door to the closed position in order to provide a latching action. <IMAGE>

Description

A DOOR CLOSER FOR A DOOR This invention relates to a door closer for a door. This invention also relates to a door when provided with the door closer.

Door closers are well known and they are used to ensure that doors are shut automatically after use.

The known door closers are mounted between the door and a frame in which the door swings.

The known door closers contain springs which are flexed as the door is opened and which return the door to its closed position when the door is released after use.

Simple known door closers do no more than return the door to its closed position after use, with the result that the door slams at the end of its return travel, making an irritating noise. Furthermore, after the simple door closers have been in use for some time, the repeated slamming of the door may cause the door frame to become loose in a building structure. Cracks may also appear in the building structure.

In order to prevent the problems associated with the known simple door closers, improved known door closers have been produced. These improved door closers have a controlled return action. They still employ springs to close the door but, in addition, they contain control means for slowing down the return swing of the door so that the door shuts more gently than it would otherwise do.

Many of the improved door closers are also provided with another refinement in the form of a latching action, whereby, as the door approaches its final rest position, movement of the door is speeded up sufficiently to overcome the opposition of a door latch, which might otherwise prevent the door closing fully.

The improved door closers incorporate within the door closer a moving piston in which is provided a one way valve. Also, the entire door closer is filled with hydraulic oil. As the door opens, oil is transferred from one side of the piston to the other through the open valve, without impeding the door movement. However, when the door is released, the piston reverses its direction of travel, which causes the valve to close. Oil can now only be returned via small ports provided in the door closer body or in the piston itself, and the speed of the door movement is therefore controllably reduced as required.

Other ports are uncovered towards the end of the piston stroke to introduce the required latching action.

The majority of known door closers now manufactured employ some form of hydraulic control as generally described above. However, all of the designs currently available suffer from one inherent disadvantage. This disadvantage is that oil is not easy to retain within the door closer.

Specialised seals are necessary and close toleranced machining and fine surface finishes are essential. Also, a high level of cleanliness is required during assembly.

Even when all of these are provided, hydraulic door closures still suffer a high incidence of early failure in service. Seals start to leak causing loss of oil, unsightly stains on doors, failure of the control action, and slamming of doors.

It is an aim of the present invention to provide an oil free door closer which has similar operating characteristics to the known improved hydraulic door closersbut which does not suffer from the above mentioned oil retention disadvantage and which thus does not require the above mentioned specialised seals, close toleranced machining, fine surface finishes and a high level of cleanliness during assembly.

Accordingly, this invention provides a door closer for a door, which door closer comprises a spring which flexes as the door opens and which returns the door to its closed position after use, braking means, a unidirectional clutch which releases the braking means when the door is opening and which engages the braking means as the door returns to its closed position, and release means for releasing the braking means towards the end of the travel of the door to the closed position in order to provide a latching action.

The door closer of the present invention may be advantageous in that, because the door closer contains no oil, the door closer maintains its controlled action more reliably, and does not suffer from the sudden complete loss of the controlled action as is often experienced from the above mentioned improved hydraulic door closers. In addition, production tolerances surface finishes and cleanliness during assembly can be less stringent than are required with the known improved hydraulic door closers.

Preferably, the spring is a torsion spring. Other types of spring may however be employed.

The braking means may comprise alternately arranged brake pads and brake plates.

The unidirectional clutch is preferably a wrap spring clutch which comprises a wrap spring.

The release means may comprise a pin operating in a slot in a body of the door closer, and a tang which is provided on the end of the wrap spring and which engages the pin in order to cause the braking means to release.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 is a longitudinal sectional view of a door closer; Figure 2 is a cross sectional view on the line X-X shown in Figure 1; Figure 3 is a cross sectional view on the line Y-Y shown in Figure 1; and Figure 4 is a perspective view of the door closer shown in Figure 1 mounted on a door.

Referring to the drawings, there is shown a door closer 37 for a door 38. The door closer 37 comprises a body 1 containing end caps 2, 3. Bearings 4, 5 are provided in the end caps 2, 3 respectively as shown. A shaft 6 is mounted in the bearings 4, 5. The shaft 6 contains a disc 7 and a drum portion 8.

The end cap 2 also contains an axial hole 9 and the shaft disc 7. The shaft disc 7 contains a slot 10.

A spring in the form of a torsion spring 11 is connected between the body 1 and the shaft 6. The torsion spring 11 is retained in position by means of a lug at one end of the torsion spring 11 which locates in the axial hole 9, and a lug at the other end of the torsion spring 11 which locates in the slot 10.

A brake bush 12 is mounted on the shaft 6 and is free to turn upon the shaft 6. The brake bush 12 contains a cylindrical portion 30 and a hexagonal portion 14. Brake pads 15, 16, 17 are mounted on the hexagonal portion 14. The brake pads 15, 16, 17 have a round outer periphery and a hexagonal central hole. The brake pads 15, 16, 17 are free to slide up and down the hexagonal portion 14 but they are not free to turn upon the hexagonal portion 14.

Brake plates 18, 19, 20, 21 are mounted within the body 1 such that they alternate with the brake pads 15, 16, 17. The brake plates 18, 19, 20, 21 locate on splines 22 provided within the body 1. The brake plates 18, 19, 20, 21 are free to slide up and down the body 1 but they are not free to turn within the body 1.

A brake spring 23 is compressed between the end cap 3 and the brake plate 21. Adjustment of pressure is provided by a threaded ring 24 which moves the end cap 2 in or out of the body 1. The brake bush 12, the brake pads 15, 16, 17, the brake plates 18, 19, 20, 21 and the brake spring 23 form braking means for the door closer 37.

The end cap 2 is tightly secured to the body 1 by a threaded ring 25.

The outer diameters of the shaft drum portion 8 and the brake bush cylindrical portion 13 are equal. Over the drum portion 8 and the cylindrical portion 13 is wound a unidirectional clutch in the form of a wrap spring clutch constituted by a wrap spring 26. The wrap spring 26 permits the shaft 6 and the brake bush 12 to turn independently as the shaft 6 rotates in one direction, but grips both the shaft 6 and the brake bush 12 firmly when the shaft 6 moves in the opposite direction, so causing both the shaft 6 and the brake bush 12 to move together.

A slot 27 is provided in the body 1. A proJecting pin 28 is secured within the slot 27. The length of the slot 27 permits some peripheral adJustment of the position of the pin 28.

A tang 29 is provided on the end of the wrap spring 26. The tang 29 is arranged to be in line with the pin 28.

A projection 30 is provided beneath the disc 7.

The body 1 is secured at one end within a bracket 31. The shaft 6 is provided with square ends 32, 33 to enable the shaft 6 to be connected at either end to drive arms 34, 35. A cap 36 is provided to cover the unused end of the shaft 6.

Referring to Figure 3, it will be seen that as the door 38 pivots, the arms 34, 35 cause the shaft 6 to rotate one way or the other way.

The wrap spring 26 is arranged so that when the shaft 6 rotates as the door 38 opens, the brake bush 12 remains free, and there is therefore no impedement to movement of the door 38 other than the return spring 11.

When the door 38 is released, the wrap spring 26 grips the cylindrical portion of the brake bush 12.

The brake bush 12 in turn pauses the brake pads 15, 16, 17 to turn between the brake plates 18, 19, 20, 21. In so doing, the brake pads 15, 16, 17 control the rate at which the door 38 now moves. The threaded ring 24 can be used to adjust this speed by increasing or decreasing the compression of the spring 23, and hence the pressure exerted by the brake plates 18, 19, 20, 21 on the brake pads 15, 16, 17.

On the opening movement of the door 38, the projection 30 contacts the tang 29 on the wrap spring 26 and carries the tang 29 around with it.

At the start of the return movement of the door 38, the wrap spring 26 immediately grips both the shaft 6 and the cylindrical portion 13 of the brake bush 12.

The tang 29 moves back, still in contact with the projection 30. However, the moment the tang 29 contacts the projecting pin 28, the wrap spring clutch releases and braking action ceases. The door 38 is now permitted to finish its travel under the unfettered influence of the torsion spring 11, which provides latching action. Thus, the prosecuting pin 28 and the tang 29 form release means for releasing the braking means towards the end of the travel of the door 38 to the closed position in order to provide the latching action.

Also, as will be appreciated, the torsion spring 11 thus flexes as the door 38 is opened and returns the door 38 to its closed position after use.

The position of the projecting pin 28 can be adjusted within the slot 27 in order to ensure that the latching action commences at the correct moment.

The shaft 6 is provided with the above mentioned square ends 32, 33 so that the door closer 37 can be used to operate both right and left edge pivoted doors 38. In order to change from one type of pivoted'door to another, it is merely necessary to withdraw the body 1 from the bracket 31, take off the cap 36 and replace the body 1 back in the bracket 31 reversed. The cap 36 can then be put back on the square end 32, 33 that was previously within the bracket 31. The closure action will then have been reversed.

As will be appreciated from the drawings, the door closer 37 is a dry door cldser which can be used as a direct replacement for hydraulic door closers, even if necessary using the same arms as those used by hydraulic door closer.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. Thus, for example, the door closer 37 can. be manufactured in a different shape to that shown in the drawings. Also, if desired, a different number of brake pads 15, 16, 17 and a different number of brake plates 18, 19, 20, 21 may be employed, depending for example upon the type and weight of the door 38 being controlled. Other forms of unidirectional clutch, for example a sprague clutch, may be employed.

Claims (7)

1. A door closer for a door, which door closer comprises a spring which flexes as the door opens and which returns the door to its closed position after use, braking means, a unidirectional clutch which releases the braking means when the door is opening and which engages the braking means as the door returns to the closed position, and release means for releasing the braking means towards the end of the travel of the door to the closed position in order to provide a latching action.

2. A door closer according to claim 1 in which the spring is a torsion spring.

3. A door closer according to claim 1 or claim 2 in which the braking means comprises alternately arranged brake pads and brake plates.

4. A door closer according to any one of the preceding claims in which the unidirectional clutch is a wrap spring clutch which comprises a wrap spring.

50 A door closer according to claim 4 in which the release means comprises a pin operating in a slot in a body of the door closer, and a tang which is provided on the end of the wrap spring and which engages the pin in order to cause the braking means to release.

6. A door closer for a door, substantially as herein described with reference to the accompanying drawings.

7. A door when provided with a door closer as claimed in any one of the preceding claims.