GB1583267A

GB1583267A - Door closer

Info

Publication number: GB1583267A
Application number: GB31518/77A
Authority: GB
Original assignee: Wartsila Oy AB
Current assignee: Wartsila Oy AB
Priority date: 1976-07-28
Filing date: 1977-07-27
Publication date: 1981-01-21
Also published as: SE410638B; FI53163C; SE7708008L; DE2732745A1; FI53163B

Description

(54) DOOR CLOSER (71) We, OY WARTSILA AB, a Finnish Company, of P.O. Box 230, 00101 Helsinki 10, Finland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a door closer comprising a piston member or the like for forcing fluid through a flow duct from one chamber to another chamber on movement of the door, and a control device for controlling the rate of flow of fluid through said flow duct during movement of the door, said control device including a control member movable to provide a throttled opening of adjustable size.

Most known door closers include adjustment screws of the needle valve type, in which, due to the considerable length of the annular throttling passage, the pressure loss in the throttling device is directly proportional to the viscosity of the hydraulic liquid, for example oil, and hence, the sensitivity of the the closer varies with the temperature.

In practice, when the temperature varies, for instance, from + 20C to - 20"C the closing time becomes about 6 times longer even when a relatively thin hydraulic oil is used. In order to compensate for this sensitivity change it is known to use a "thin" hydraulic liquid, i.e. a liquid with a viscosity index as high as possible, and/or a variable, thermostatically controlled throttled opening.

In hydraulic apparatus short throttled passages are also commonly used and the aim has been to make the edges of the throttled opening sharp. There is a practical difficulty when applying this solution to a door closer in that the flow to be controlled is very small, below 1 1 Imin, so that the cross-section of the throttled opening has to be very small, about 0.3-0.5 mm2. It is difficult to make the control of a throttled opening of this size steplessly variable. A known solution is presented in Swedish Patent Specification No. 387 438, according to which a separate sleeve is used, which is fitted in the body of the door closer. This is because the fit between the sleeve and the adjustment screw has to be practically without clearance, which requires a higher manufacturing accuracy than what is usual in door closers.In addition, the fit between the outer surface of the sleeve and the body of the door closer has to be sealed, which is liable to increase further the manufacturing costs of the door closer.

The present invention aims to - provide a door closer, the operation of which is practically independent of temperature fluctuations and from which the drawbacks of conventional door closers of the same kind have been essentially eliminated.

According to the invention a door closer comprises a piston member or the like for forcing fluid through a flow duct from one chamber to another chamber on movement of the door, and a control device for controlling the rate of fluid through said flow duct during movement of the door, said control device including a control member turnably located in a bore of the door closer and having a tubular end provided provided with a throttled opening in the form of a slot in the wall of the tubular end of the control member, the adjustment of the size of the throttled opening available to fluid flow being steplessly effected by turning the control member in its bore to move the slot relative to the flow duct.

With a door closer in accordance with the invention variations, due to temperature fluctuations, in the viscosity of the hydraulic liquid and in the pressure losses within the throttling device are fairly well mastered in a simple way and at the same time a steplessly variable control of the flow is obtained which does not result in an unreasonably complicated construction with respect to manufacture and installation. When a throt tled opening is very small it is of advantage for the throttling and for the control thereof, to have the opening slot-formed, because a slot can be designed so that it is not too narrow in any direction and thus the risk of it being blocked is minimised. In this respect an annular clearance is inferior. Its adjustability is also difficult to arrange with sufficient accuracy.

Since the flow to be controlled is very small, it is important to make the main part of the flow to pass through a slot whose entrance from the flow duct is defined by sharp edges. A part of the flow is inclined to leak through the clearances of the construction where the throttled passage is long, with the result that the pressure loss caused by this throttling becomes very strongly dependent on the viscosity of the hydraulic liquid. Hence, a circumferential groove can be arranged adjacent to one end of the sleeve-formed control member to improve its resilience and/or the control member is arranged to have a somewhat overlarge diameter to fit tightly in its place.

If the control device is located cross-wise with respect to the flow duct, the length of the portion of the throttled slot through which fluid flows when the control member is in its normal position should preferably be, at its largest, less than 30% of the diameter of the flow duct. When dimensioned in this way, the variation of the flow-permitting portion of the throttled slot follows the adjusting movement more linearly than if said portion were axially longer. In the latter case, the variation of the free cross-sectional area of the throttled slot would be relatively small at the beginning, but would be much more intense upon further turning of the control member.

When the control device is arranged crosswise in the flow duct, it is of advantage to provide the control member with a second slot located opposite to the throttled slot, said second slot being preferably at least three times as wide as the throttled slot, to make it easier to manufacture the throttled slot.

Furthermore, when the control device is arranged crosswise in the flow duct, it is also of advantage for the operation of said device to have two throttled slots in the control member located opposite each other, because then the pressure loss in each slot is reduced, which contributes to making the flow independent of the temperature. However, the embodiment with two throttled slots requires a more complicated manufacturing technique, and consequently, is more expensive to accomplish than the embodiment with one slot only.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which Figure 1 is a schematic sectional view of a control device of a door closer according to the invention Figure 2 is a sectional view taken on the line II--II of Figure 1, Figure 3 is a schematic sectional view of another control device of a door closer according to the invention, Figure 4 is a sectional view taken on the line IV-IV of Figure 3, and Figure 5 is a schematic sectional view of a third control device of a door closer according to the invention.

As a rule, a door closer includes a springloaded piston member which, due to the movements of the door, forces hydraulic fluid, for example oil, through a flow duct from one cylinder chamber to another. By controlling said flow, the movements of the door can be regulated as wished. The above described conventional general construction of a door closer is only partly shown in the drawings, in which the same reference numerals are used in the various Figures to designate the same or similar items. In the drawings, the numeral 1 designates the said piston member, 2 the body of the door closer, 3 said flow duct and 4 a control device for the flow including a control member 5 which comprises a throttled slot 6. The control member 5 includes a groove 8 to improve the resilience of its tubular distal end and thereby improve the sealing of that end in the flow duct 3.In order to control the size of the throttled slot 6 the flow duct includes a counter surface or a wall 7. In addition, in order to make it easier to manufacture the throttled slot, the control member 5 of the control device according to Figure 3 comprises another, somewhat wider slot 9 opposite the throttled slot 6. In the embodiment shown in Figure 5, there is, instead of the slot 9, a throttled slot 10, preferably of the same kind as the throttled slot 6. The control of the size of the throttled slot 6 is accomplished by turning the control device 4 which preferably is an adjustment screw, connected by screw threads to the body 2 of the door closer.Depending on the turning direction, the counter surface 7 in the flow duct 3 covers more or less of the throttled slot 6 which turns together with the control device 4, whereby the cross-sectional area of the passage available to flow varies accordingly.

The control device 4 shown in Figures 1 and 2 moves axially with respect to the flow duct 3, guided by screw threads, which movement actually accomplishes the control function. In the embodiments shown in Figures 3, 4 and 5, the control device 4 moves cross-wise with respect to the flow duct 3. In this case the actual control is accomplished by a turning movement within a certain turning sector. When the control device is arranged cross-wise in the flow duct, another control range can be reached, when desired, by turning the control device 4 one or more full turns. Thus, in the embodiment shown in Figure 5, a new control range is reached upon each turn of the control device 4 through half a turn, and the control of the size of both the throttled slots (6 and 10) is accomplished by the same control movement.

In spite of the possible change from one control range to another, a steplessly variable control is obtained, because the different control ranges overlap one another It will be noted that the entrance to the slot 6 from the flow duct is defined by sharp edges. It will also be noted from Figures 1 and 2 that control member 5 is relatively thin walled, by which we mean that the wall thickness of the tubular end in which the slot 6 is formed is substantially equal to the maximum width of the slot, at its entrance from the flow duct, measured normal to the axial direction of the slot. The sharp edged entrance to the slot and thin walled construction are important in decreasing the sensitivity of the door closer to temperature fluctuations.

WHAT WE CLAIM IS:- 1. A door closer comprising a piston member or the like for forcing fluid through a flow duct from one chamber to another chamber on movement of the door, and a control device for controlling the rate of flow of fluid through said flow duct during movement of the door, said control device including a control member turnably located in a bore of the door closer and having a tubular end provided with a throttled op en- ing in the form of a slot in the wall of the tubular end of the control member, the adjustment of the size of the throttled opening available to fluid flow being steplessly effected by turning the control member in its bore to move the slot relative to the flow duct.

2. A door closer according to claim 1, in which said slot in the control member extends in an axial direction relative to the axis about which the control member turns in its bore.

3. A door closer according to claim 2, in which the control member is screwthreadedly mounted in its bore.

4. A door closer according to claim 1, 2 or 3, in which the tubular end of the control member is made more flexible relative to a portion thereof screw-threadedly received in the bore, by the provision of a radial groove between the slot and said portion.

5. A door closer according to any preceding claim, in which the tubular end of the control member is dimensioned to have a somewhat overlarge diameter relative to the bore which receives it, whereby said bore is sealed against fluid flow otherwise than through said slot.

6. A door closer according to claim 2 or any claim dependent on claim 2, in which the wall thickness of the tubular end in which the slot is formed is substantially equal to the maximum width of the slot, at its entrance from the flow duct, measured normal to said axial direction.

7. A door closer according to any preceding claim, in which the entrance to the slot from the flow duct is defined by sharp edges.

8. A door closer according to any of the preceding claims, in which the control member is arranged to move in its bore in directions transverse to the flow duct.

9. A door closer according to claim 8, in which the length of that portion of the throttled slot available for fluid flow, in the normal position of the control member, is less than 30% of the diameter of the flow duct.

10. A door closer according to claim 8 or 9, in which the control member is provided with a second slot in the tubular end, which second slot is diametrically opposite to the throtted slot.

11. A door closer according to claim 10, in which said second slot is at least three times as wide as said throttled slot.

12. A door closer according to claim 8 or 9, in which the control member has a second slot, of substantially the same dimensions as the throttled slot, the second slot being diametrically disposed in the tubular end relative to the throttled slot.

13. A door closer constructed and arranged substantially as herein described with reference to Figures 1 and 2, Figures 3 and 4 or Figure 5 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. accomplished by the same control movement. In spite of the possible change from one control range to another, a steplessly variable control is obtained, because the different control ranges overlap one another It will be noted that the entrance to the slot 6 from the flow duct is defined by sharp edges. It will also be noted from Figures 1 and 2 that control member 5 is relatively thin walled, by which we mean that the wall thickness of the tubular end in which the slot 6 is formed is substantially equal to the maximum width of the slot, at its entrance from the flow duct, measured normal to the axial direction of the slot. The sharp edged entrance to the slot and thin walled construction are important in decreasing the sensitivity of the door closer to temperature fluctuations. WHAT WE CLAIM IS:-

1. A door closer comprising a piston member or the like for forcing fluid through a flow duct from one chamber to another chamber on movement of the door, and a control device for controlling the rate of flow of fluid through said flow duct during movement of the door, said control device including a control member turnably located in a bore of the door closer and having a tubular end provided with a throttled op en- ing in the form of a slot in the wall of the tubular end of the control member, the adjustment of the size of the throttled opening available to fluid flow being steplessly effected by turning the control member in its bore to move the slot relative to the flow duct.