GB2108577A

GB2108577A - Door closing device

Info

Publication number: GB2108577A
Application number: GB08229156A
Authority: GB
Inventors: Neil John Irwin Adams; John Irwin Adams
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-10-15
Filing date: 1982-10-12
Publication date: 1983-05-18
Also published as: GB2108577B

Abstract

A door closing device comprising a cylinder 12 in which a piston 13 is slidably located. A spring 25 urges the piston 13 towards one end and a rod 21 is slidably located in a bore 18 in the piston 13. The piston 13 has a rack gear 17 which meshes with a pinion 32 on a spindle 31 so that rotation of the spindle 31 moves the piston 13 in the cylinder 12. The cylinder 12 is attached to the door and the spindle 31 is attached to the door frame via a linkage arranged to rotate the spindle 31 as the door opens and closes. A non-return valve 19 allows hydraulic fluid to pass the piston 13 when it is moved against the spring 25 upon opening the door but when the spring 25 returns the piston 13 to close the door, the fluid is forced to return via a groove 29 in the rod 21, an eccentric groove 27 in the bore 18 and a conduit 28. Angular adjustment of the groove 29 with respect to the eccentric groove 27 varies the damping effect of the fluid on the return force of the spring 25. <IMAGE>

Description

SPECIFICATION Door closing device The present invention relates to a door closing device.

Door closing devices are known which comprise a unit in which opening the door causes relative movement between two elements. This in turn compresses a closure spring which closes the door when it is released. The movement of the door in closing causes hydraulic fluid to be forced through a constricted passage, thereby controlling the effect of the closure spring.

Door closers of this type are satisfactory in many conditions but it has been found that they suffer certain disadvantages in controlling the door at either the wide open position or at the point of closing.

It is an object of the present invention to provide a door closing device which may provide effective control of the door over its full range of movement from the wide open position to the closing point when it may be necessary to overcome a door catch.

It is a further object of the present invention to provide a door closing device whose closing speed may be adjusted.

It is a further object to provide a door closing device which may be adjusted so that its closing speed increases at a point during the movement of the door, for example shortly before the door catch is to be overcome.

According to the present invention a door closing device comprises a cylinder; a piston slidably located within the cylinder, the piston having an axial bore with an eccentric portion and a fluid non-return valve between the two parts of the cylinder on either side of the piston; a spindle co-operating with the piston and arranged, upon rotation, to move the piston axially in the cylinder; biassing means urging the piston towards one end of the cylinder, the non-return valve being in the open position when the piston moves against the biassing means; and a rod slidably located within the bore in the piston and rotatably mounted with respect to the piston, the rod defining within the bore an axially extending channel communicating with the eccentric portion to a varying extent in dependence upon the relative angular orientation of the rod and the piston, the channel also affording communication between the two parts of the cylinder on either side of the piston.

Preferably, the device according to the invention is attached to the door and the spindle connected to the door frame via a linkage which causes the spindle to rotate as the door is opened and closed. Alternatively, the device may be attached to the door frame and the linkage connected between the spindle and the door, with the same effect.

Preferably, the co-operation between the spindle and the piston is achieved by means of a rack gear on the piston and a pinion on the spindle. The biassing means may be a compression spring acting between the piston and the said other end of the cylinder, which is preferably filled with a hydraulic fluid.

The eccentric portion preferably extends for a part only of the length of the bore. The eccentric portion is preferably generally circular with a centre which is off-set from the axis of the bore.

Such an eccentric portion would have a larger diameter than that of the bore. Alternatively, the eccentric portion may be elliptical in shape or may have a cut-out in its perimeter, or may have any other feature which causes its boundary to extend beyond the position which would otherwise have been occupied by the wall of the bore in that position.

Preferably, the piston has a conduit extending from the eccentric portion to that part of the cylinder at its said other end. Thus, prior to the piston reaching the end of its travel due to its movement under the action of the biassing means, the eccentric portion and conduit may move to a position which may allow a relatively unrestricted path from one side of the piston to the other via the conduit. The position at which the said relatively unrestricted path first occurs may be adjustable by moving the rod axially with respect to the cylinder.

Alternatively, the rod may be in two relatively rotatable parts, each having an axial groove which may be independently adjusted angularly with respect to the eccentric portion. In such a case, as the piston moves under the action of the biassing means, the resistance to fluid flow from one side of the piston to the other via the conduit may be varied as the eccentric groove changes from being in registration with the groove in one part of the rod to being in registration with the groove in the other part of the rod.

The invention may be carried into practice in various ways and two embodiments will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a horizontal axial section through a door closing device according to one embodiment of the present invention; Figure 2 is a simplified partial vertical crosssection through the rod and piston of Figure 1; Figure 3 is an elevation of the fixed end of the rod to a larger scale; Figure 4 is an elevational view of the device of Figure 1; Figure 5 is a view similar to Figure 1 showing a second embodiment; and Figure 6 is a view similar to Figure 2 showing the embodiment of Figure 5.

The device shown in Figures 1 to 4 comprises a housing 11 defining a cylinder 12 in which a piston 1 3 is slidably mounted. The housing 11 may be aluminium alloy casting while the piston is machined from mild steel. The cylinder 1 2 is filled with hydraulic fluid and is formed with a reservoir 14 at one end.

The piston 13 has a cylindrical portion 1 5 which is a close fit in the cylinder 12 and a cutaway portion 1 6 on which a rack gear 1 7 is formed. A central bore 1 8 passes through the piston 1 3 and a non-return valve 1 9 is located in the cylindrical portion 1 5 connecting the two portions of the cylinder 12 on either side of the piston 13.

A rod 21 has one end slidably located in the bore 1 8 and the other end rotatably mounted in an end plug 22 which is rotatably mounted in the end of the cylinder 12 which is opposite the reservoir 14. Hydraulic seals are achieved between the cylinder 12, the end plug 22 and the rod 21 by means of sealing rings 23 and 24. A closure spring 25 acts between a flange 26 on the end plug 22 and the piston 13 to urge the piston 13 towards the reservoir 14.

At a position near the cylindrical portion 1 5, the bore 1 8 has an eccentric groove 27 at the deepest point of which a conduit 28 is formed which connects the eccentric groove 27 with that portion of the cylinder 1 2 opposite the reservoir 14. The portion of the rod 21 which is located in the bore 18 has a longitudinal groove 29. A spindle 31 is mounted within the housing 11 and has a pinion 32 which meshes with the rack 1 7 on the piston 1 3.

In use, the housing 11 is attached to a door by means of screw holes 33 and the spindle 31 is connected to the door frame by means of a hinged linkage so that as the door is opened and closed, the spindle 31 is rotated. Referring to Figure 1, as the door is opened, the spindle 31 is turned anticlockwise, and the piston 1 3 is moved to the left, thus compressing the closure spring 25. At the same time, hydraulic fluid moves to the right and passes into the reservoir 14 via the non-return valve 19 which allows movement of fluid in this direction.

In the open position, the piston 13 is further to the left than it is shown in Figure 1 , with the rod 21 protruding beyond the right-hand end of the piston 13. When the door is released, the spring 25 tends to force the piston to the right in Figure 1, turning the spindle 31 clockwise, thus tending to close the door. However, the fluid cannot pass through the valve 1 9 to the left and must therefore travel from the reservoir 14 along the axial groove 29, into the eccentric groove 27 and through the conduit 28 into the space beyond. This has a damping effect on the closing of the door.

In order to adjust the damping effect and so the door closing speed it is simply necessary to rotate the rod 21 with respect to the housing 11 and the piston 1 3 which is prevented from rotating by the spindle 31. As shown in Figure 2, rotating of the rod 21 causes the position of the axial groove 29 to change relative to the eccentric groove 27, resulting in a greater or smaller resistance to fluid flow, depending upon whether the rod is turned anti-clockwise or clockwise.

When the end of the rod 21 passes the eccentric groove 27, the flow restricting effect of the eccentric groove is no longer felt and so the door closes more rapidly. This acceleration position may be adjusted by moving the rod 21 axially with respect to the end plug 22. As shown in Figure 3, this may be achieved by means of a screw thread connection 34 between the rod 21 and the end plug 22. Thus, the device can be adjusted so that the door, in closing, will accelerate just as approaches the door catch or latch, in order to overcome the extra resistance.

A second embodiment is shown in Figures 5 and 6 in which similar reference numerals to those used in Figures 1 to 4 are used to designate similar components. In this embodiment, the rod is in two parts 41 and 42. The first part 41 is in the form of a sleeve and is a tight fit in the end plug 22 while the second part 42 has an end portion 43 which is flush with the sleeve 41 and a spigot 44 which is rotatably located in the sleeve 41. A sealing ring 45 is located between the sleeve and spigot in the region of the end plug 22.

The sleeve 41 has a groove 46 in the region which extends into the piston 1 3 and the end portion 43 has a similar groove 47. Thus, by independently adjusting the angular position of these grooves 46, 47 with respect to the eccentric groove 27 the closing speed can be varied as the door closes.

It will be appreciated that one of the great advantages of these door closing devices in accordance with the invention is that they can be used to close doors of different sizes and weights in the desired manner, and furthermore, the necessary adjustments can be made in situ.

Claims

1. A door closing device comprising a cylinder; a piston slidably located within the cylinder, the piston having an axial bore with an eccentric portion and a fluidlnon-return valve between the two parts of the cylinder on either side of the piston; a spindle co-operating with the piston and arranged, upon rotation, to move the piston axially in the cylinder; biassing means urging the piston towards one end of the cylinder, the non-return valve being in the open position when the piston moves against the biassing means; and a rod slidably located within the bore in the piston and rotatably mounted with respect to the piston, the rod defining within the bore an axially extending channel communicating with the eccentric portion to a varying extent in dependence upon the relative angular orientation of the rod and the piston, the channel also affording communication between the two parts of the cylinder on either side of the piston.

2. A device as claimed in Claim 1 In which the co-operation between the spindle and the piston is by means of a rack gear on the piston and a pinion on the spindle.

3. A device as claimed in Claim 1 or Claim 2 in which the biassing means is a compression spring acting between the piston and the said other end of the cylinder.

4. A device as claimed in any preceding claim in which the cylinder is filled with a hydraulic fluid.

5. A device as claimed in any preceding claim in which the eccentric portion extends for a part only of the length of the bore.

6. A device as claimed in any preceding claim in which the channel comprises an axial groove in the rod.

7. A device as claimed in any preceding claim in which the piston has a conduit extending from the eccentric portion to that part of the cylinder at its said other end.

8. A device as claimed in Claim 7 in which the speed of movement of the piston due to the biassing means is controlled by the relative position of the axial groove in the rod and the depth of the eccentric portion restricting the flow of fluid.

9. A device as claimed in Claim 7 or Claim 8 in which, prior to the piston reaching the end of its travel due to its movement under the action of the biassing means, the eccentric portion and conduit move to a position which allows a relatively unrestricted path from one side of the piston to the other via the conduit.

10. A device as claimed in Claim 9 in which the position at which the said relatively unrestricted path first occurs is adjustable by moving the rod axially with respect to the cylinder.

11. A device as claimed in any of Claims 1 to 7 in which the rod is in two relatively rotatable parts, each having an axial groove which may be independently adjusted angularly with respect to the eccentric portion, and in which as the piston moves under the action of the biassing means, the resistance to fluid flow from one side of the piston to the other via the conduit may be varied as the eccentric groove changes from being in registration with the groove in one part of the rod to being in registration with the groove in the other part of the rod.

12. A door closing device constructed and arranged substantially as herein specifically described with reference to and as shown in Figures 1 to 4 or 5 to 6 of the accompanying drawings.

I 3. A door installation including a device as claimed in any preceding claim in which the device is attached to the door or the door frame and the spindle is connected to the door frame or the door respectively via a linkage which causes the spindle to rotate as the door is opened and closed.