GB2244759A - Door closing device - Google Patents

Abstract

A door-closer comprises a piston 14 connected by a rod 16 with a cam mechanism 17 to 22 for converting reciprocation of the piston to rotary motion of a door-pivoting shaft 11. At one end, the rod 16 has a valve element 33 which is normally urged onto a seat 34 in the piston by the retain spring 13. If an unusually high pressure is established at one side 26 of the piston, for example by unusually rapid closing movement of an associated door, the pressure can prevent the piston moving with the valve element 33 and the rod so that the passage 32 through the piston is opened to relieve the pressure. Alternatively (Fig. 3, not shown) the piston is connected directly to carrier 17, and piston rod 16 extends to a spring abutting nut at the opposite closer end, the nut being adjustable from outside the closer to adjust spring tension and thus the pressure at which valve 34 lifts. The spring abutment on the closer housing may also be adjustable. <IMAGE>

Description

Title: Door-Closing Device Description of Invention The present invention relates to a device suitable for closing a door and comprising a hollow housing, an operating element accessible from outside the housing and movable relative to the housing, a sprung disposed inside the housing and transmitting means for transmitting motion between the spring and the operating element. In use, one of the housing and the operating element is anchored on the door or another movable closure member and the other of the housing and the operating element is anchored with respect to a fixed structure, for example a flcor or a frame defining an opening which is closed by the door.

Opening movement of the door is transmitted to the spring to stress the spring and thereby store energy in the spring. when the door is released, that energy is expended in closing the door.

To restrict the speed at which the device moves the door. he housing of a device of this icing is generally charged with a damping fluid and the transmitting means Incorporates a piston. X passage is provided ro permit the damping fluid to flow from one side of the piston to the other at a controlled rate. In some cases, a valve is provided for closing the passage so that movement of the piston in the housing can be restricted or prevented.In a case where the damping fluid is substantially incompressibie. it is then possible for large forces to be exerted on components of the device. A pivoted door is a large lever and if a person applies considerable force to a portion of the door remote from the pivot, the torque exerted and therefor the force exerted on the closing device rnav be sufficiently high to damage the device. To reduce the risk of such damage occurring, it is desirable to incorporate a relief valve which will open to permit flow of fluid past the piston in the event of an excessively high pressure being established in one part of the housing.

According to the present invention, a device of the kind described which includes a piston defining a passage for the flow of fluid through the piston and having a valve element for controlling the passage and a valve seat on which he valve element bears when the passage is closed by the valve element, is characterised in that the path for transmission of force from the spring to the operating element includes the valve element and the valve seat, the arrangement being such that the valve eiement is urged towards its seat by a force transmitted between the spring and the operating eiement.

The device may include adjustment means for aciUstirg the position of an abutment on which the spring bears, in order to vary the stress to which the spring is subjected, when the stored energy has been expended by the spring. In this case, the characterising feature of the invention has the advantage that the force which urges the valve element towards its seat also will be varied by adjustment of the device.

Examples of devices embodying the invention will now be described, with reference to the accompanying drawings, wherein FIGE I shows a cross section through a door-closing device, partly in a plane containing a longitudinal axis of a piston of the device and partly in another plane parallel to that axis, FIG?RE 2 shows a cam and follower mechanism of he device as viewed In tie direction indicated by he arrow 7I in Figure 1 and FIGURE 3 is a cross section similar to Figure 1 illustrating an alternative device.

The device illustrated in Figures 1 and 2 comprises a hoilow.

elongated housing 10 and a shaft 11 which is mounted in the housing near to one end thereof for turning relative to the housing about a longitudinal axis 12 of the shaft, which axis is perpenåicllar to the length of the housing. The housing is provided with bearings (not shown) for supporting the shaft. The shaft protrudes through at least one of these bearings to the outside of the housing and there is associated with this bearing a seal to prevent escape of oil from inside the housing. The shaft 11 constitutes an operating element of the device and, when the device is in use, is connected with a door or other movable closure member.

The door may be mounted for pivoting about the axis 12, in which case the protruding part of the shaft may constitute a pivot for the door. The protruding part of the shaft or an adaptor mounted thereon may be received in a socket formed in the door. Alternatively, the protruding part of the shaft may be connected with the door by means of a bracket. Alternatively, the pivot axis of the door may be offset from the axis 12, in which case the shaft is connected with the door by a suitable linkage. 71en the device is in use, the housing 10 is mounted in or on a fixed structure, for example a floor or a frame of the door or other closure member.

It would also be within the scope of the invention to mount the housing 10 on the door and to connect the protruding portion of the shaft 11 with a frame or other fixed structure by means of a suitable linkage.

There is disposed inside the housing 10 a spring 13 for storing energy when the door or other associated closure member is opened, so that the stored energy can subsequently be used for closing the door. The device further comprises transmitting means for transmitting motion between the spring and the shaft 11 both when the door is being opened and when the door is being closed by the spring.The transmitting means includes a piston 14 for damping movement of the shaft 11 under the action or the spring 13 se that the speed at which the door is closed is restncted. The piston rec.procates in a c'ìindrlcal bore defined bv the housing 10. this sore being closed at an end of the housing remote from the shaft 11 by a plug and communicating at its other end with a non-cylindrical space inside the housing.

In the example illustrated in Figure 1, the spring 13 bears directly on the piston 11 and on an abutment 15 formed at the inside of the housing 10.

The spring 13 is a coiled compression spring and is substantially cvlindrical. The piston has a rod 16 extending along the interior of the spring to a mechanism for converting reciprocation of the piston to rotary motion of the shaft 11. In the particular example illustrated, this mechanism is a cam and follower mechanism.

However, it would be within the scope of the invention for other mechanisms having a similar function to be used, for example a rack and opinion mechanism or a crank mechanism. The cam and follower mechanism of the device illustrated in Figure 1 provides for turning of the shaft 11 from a datum position in either direction through an angle approaching 1800, provides a well-defined datum position and permits the shaft 11 to be disposed near to an end of the housing 10.

The piston rod 16 is connected adjacent to an end thereof remote from the piston 14 with a carrier 17 which is guided for reciprocation inside the housing tO along a path which is perpendicular to the axis 12. An elongated aperture 18 is formed in the carrier and the shaft 11 extends through this aperture with sliding clearance. On the carrier, there are mounted a number of followers for cooperation with a cam 19 provided on the shaft 11. The cam has two cam faces, both of which face away from the axis 12 and which lie at different positions along that axis.

There is on the carrier 17 adjacent to an end thereof remote from the piston rod 16 a group of three cam followers 20, 21 and 22 respectively. Each follower is mounted rotatably on a respective stub which is fixed with respect to the carrier 17. The stubs are arranged in a curved row on the follower. The followers 20 and 22 at opposite ends of the row cooperate with a first of the cam faces 23. The follower 21, which lies between the followers 20 and 22 s arranged to cooperate with the second cam face 24.

The .prong 13 normally urges one or more of he foliowers, 20, 21 and 22 against the cam 19. To ensure that the followers do not move awav from the cam, there may be provided on the carrier 17 an additional follower 25 which lies at the side of the axis 12 remote from the cam follower 21 and which cooperates with the second cam face 24.

The carrier 17 is urged by the spring 13 to the datum position shown in Figure 1. When the carrier is in this position the followers 20 and 22 both bear on at least approximately tlat portion of the first cam face 23. Since the followers 20 and 22 are spaced equally from the piston 14, they hold the cam 19 and therefore the shaft 11 in a datum position. This position corresponds to the closed position of the door controlled by the device. The respective positions where the followers 20 and 22 bear on the cam face 23 are spaced well apart and this ensures that the datum position is well-defined. Turning of the cam 19 through an angle of only one or two degrees from the datum position is opposed by the spring.

women the cam i9 is in the datum position, there is a clearance between the follower 21 and the second cam face 24. As the cam 19 is turned in either direction, relative to the housing 10, for example by opening of the associated door, the cam face 24 moves into contact with the follower 21.

Through a substantial range of angular movement, for example 60 or more, the cam 19 acts on two of the three followers 20, 21 and 22 to drive the carrier 17 along the housing 10 and thereby compress the spring 13.

Over an initial range of movement, for example up to approximately 90" from the datum position, the device provides an approximately uniform force opposing opening movement of the door. The cam faces 23 and 24 are formed to provide a significantly greater force opposing opening movement of the door as the cam 19 completes 90" of movement from the datum position.

If movement of the cam 19 is continued beyond 900 from the datum position, then the action of the cam face 24 on the follower 21 moves the carver 17 sufficiently far for one of the followers 20 and 22 to move out of contact with the cam face 23 the other of the followers 20 and 22 being already out of contact). Movement of the cam 19 and shaft 11 can continue untii almost 1800 of movement has been completed from the datum position. The shaft can be turned in either direction from the datum position so that the perriitted range of movement is approximately 3600.

If the associated door is released, the spring 13 extends to drive the piston 14 and the carrier 17 along the housing 10 so that the cam followers drive the cam 19 around the axis 12 towards the datum position. In order to limit the speed at which the shaft is turned back to the datum position, the interior of the housing 10 is charged with an hydraulic fluid which must be displaced, in order for the piston to travel along the housing. One or more passages is provided to permit hydraulic fluid to flow from a chamber 26 inside the housing at the pressure side of the piston to the chamber 27 inside the housing at the opposite side of the piston. By way of example, there is represented a passage 28 formed in the wall of the housing 10 and an adjustable needle valve 29 for controlling flow of hydraulic fluid along the passage.It will be understood that other, known arrangements for permitting controlled flow of hydraulic fluid may be incorporated in the device and these may include one or more passages in the piston or extending through the piston.

To permit substantially unimpeded flow of hydraulic fluid from the chamber 27 to the chamber 26, during opening of an associated door, there is provided a further passage 30 containing a non-return valve 31. By way of example, the passage 30 is shown in the wall of the housing 10 but this passage also could be provided in the piston.

A third passage 32 extends through the piston 14 from the pressure chamber 26 to the chamber 27. The passage 32 is normally closed by a valve element 33 which bears on a valve seat 34 provided in the piston. The valve seat may be formed of a resiliently flexible material to facilitate sealing of the passage 32 by the valve element 33. The valve element 33 is formed integrally with or is rigidly mounted on the piston rod 16 so that the seat 34 is urged onto the valve element 33 by the spring 13. Throughout normal operation of the device, the passage 32 remains closed.

In the event of an associated door being forced from an open position towards a closed position ciently, the torque exerted on 'he shaft 11 by the door may drive the carrier :7 and the piston 14 to the left. as viewed in figure 1, so rapidly hat there is established in the chamber 26 a pressure which is sufficiently great to overcome the action of the spring 13. In this events the spring fails to hold the seat 34 in engagement with the valve element 33 and the valve element is driven towards the left, as viewed in Figure 1, relative to the piston. This opens the passage 32 for flow of hydraulic fluid directly through the piston from the chamber 26 to the chamber 27 and thereby avoids the device being damaged by the application of excessive torque to the shaft 11. It will be understood that a person exerting force on a marginal portion of a door remote from its pivot axis can exert an extremely high torque on the shaft 11.

The arrangement limits the pressure which can be established in the chamber 26. The exact value of the limiting pressure will depend upon the degree of extension of the spring 13 and will vary during travel of the piston.

Certain parts of the door closer illustrated in Figure 3 correspond to parts hereinbefore described with reference to Figures 1 and 2. In Figure 3, such corresponding parts are identified by like reference numerals with the prefix 1.

The preceding description is deemed to apply to such corresponding parts, except for the differences hereinafter mentioned.

The device illustrated in Figure 3 differs from that of Figure 1 in that the device of Figure 3 incorporates adjustment means for adjusting the stress to which the spring 113 is subjected, when the carrier 117 is in a given position.

The piston 1'4 is disposed in a position between the spring 113 and the carrier 117 and the carrier is attached directly to the piston, for example by means of a gudgeon pin.

A rod 116 extends from the piston 114 along the interior of the spring 113 and an end portion of the rod remote from the piston is formed with a male screw thread. This thread cooperates with a complimentary thread in a nut 135 which constitutes one abutment for the spring 113. The other abutment for the spring is formed in or is fixed with respect to the housing 110.

Drive means is provided for turning the nut i35 to drive the nut along the rod 116. The head 133 of the rod is arranged to cooperate with the piston 114 to restrain turning of the rod relative to the piston and turning of the piston relative to the housing is prevented by the carrier 17. The drive means illustrated by way of example in Figure 3 comprises a circular plate 136 disposed inside the housing 110 at that end of the housing which is remote from the cam i19. A stub 137 protrudes from the plate 136 to the outside of the housing through suitable seais. By means of the stub, the plate can be turned relative to the housing. A number of fingers 138 extend from the plate 136 along wails of the housing and pass through notches formed in the nut 135 at its periphery.The fingers transmit rotary drive from the plate 136 to the nut, whilst permitting relative axial movement.

In the device of Figure 3, there are provided passages for permitting the flow of hydraulic fluid between the chambers 126 and 127. These passages may be arranged in substantially the same way as the passages 28 and 30 of the device of Figure 1 are arranged. Thus, the necessary passages may be formed in the wall of the housing 10 or in the piston. By way of example, there is shown in Figure 3 one passage 130 which provides communication between the chambers 126 and 127.

During normal operation of the device of Figure 3, the head 133 on the rod 116 is held by the spring 133 in contact with its seat 134 in the piston.

The passage 132 through the piston is closed throughout normal operation of the device.

In the event of an unusually high torque being applied to the shaft 111 in a direction tending to drive the piston 114 away from the shaft 111, the pressure in the chamber 26 may increase to a level at which that pressure is able to force the head 133 from its seat 134 against the action of the spring 133. This opens the passage 132 through the piston and limits the pressure which can be established in the chamber 126. Once the head 133 has lifted off its seat 134, the relatively high pressure in the chamber 125 is exerted on a larger area of the head 133 and this maintains the head in an open position until the pressure in the chamber 126 falls considerabiv.

It will be understood what, in the case of both of the devices shown n the accompanying drawings during, application to the shaft 11 of an unusually high torque in a direction tending to drawn the piston towards :he shaft, establishment of an excessively high pressure in the chamber 27 or 127, as the case may be, is avoided by the relatively unimpeded flow of hydraulic fluid past the non-return valve.

As an alternarive to the adjusting arrangement of Figure 3, provision may be made for adjustment of the abutment for the spring which is on the housing. This form of adjusting means may be provided in either the device of Figure 1 or the device of Figure 3.

It will be noted that, in each case, the limiting pressure which can be established in the pressure chamber 26 or 126 is determined by the stress in the spring. Adjustment of the device to stress the spring more highly, for example for use with a larger door, automatically adjusts the limiting pressure so that the limiting pressure has a higher value when the spring is more highly stressed.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terns 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 (8)

1. A device comprising a hollow housing, an operating element which protrudes from the housing and is movable relative to the housing, a spring disposed inside the housing and transmitting means for transmitting motion between the spring and the operating element, wherein the transmitting means includes a piston arranged for reciprocation inside the housing when the operating element moves relative to the housing, the piston defines a passage for the flow of fluid through the piston, the piston has a valve element for closing the passage and the piston has a valve seat on which the valve element bears when the passage is closed by the valve element, characterised in that the path for transmission of force from the spring to the operating element includes the valve element and the valve seat, the arrangement being such that the valve element is urged towards its seat by the force transmitted between the spring and the operating element.

2. A device according to Claim ' wherein the piston and the housing have respective abutments, the spring bears on such abutments and wherein adjusting means is provided for adjusting the position of one of the abutments relative to one of the housing and the piston.

3. A device according to Claim 1 or Claim 2 wherein the piston separates first and second parts of the space inside the housing, the spring lies in the first part, the valve element has a smaller area exposed to the first part of said space and the valve element has a larger area exposed to the second part of said space.

4. A device according to Claim 1 wherein the spring is a coiled spring, the valve element comprises a head which bears on the seat and a stem which extends along the interior of the spring and wherein an abutment for the spring is provided on the stem, the abutment and the head being adjacent to opposite ends of the stem.

5. A device according to Claim 1 wherein the spring is a coiled spring, the transmitting means further includes a mechanism for converting rotary motion to reciprocation, the spring lies substantially between the piston and said mechanism, the valve element comprises a head which bears on the seat and a stem which extends along the interior of the spring to said mechanism.

6. A device substantially as herein described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

7. A device according to Claim 6 modified substantially as herein described with reference to and as shown in Figure 3 of the accompanying drawings.

8. Any novel feature or novel combination of features disclosed herein or in the accompanying drawings.