GB1570260A

GB1570260A - Releasable retaining means

Info

Publication number: GB1570260A
Application number: GB378778A
Authority: GB
Original assignee: Dorgard Ltd
Current assignee: Dorgard Ltd
Priority date: 1978-01-31
Filing date: 1978-01-31
Publication date: 1980-06-25

Description

(54) IMPROVEMENTS IN OR RELATING TO RELEASABLE RETAINING MEANS (71) We, DORGARD LIMITED, a British Company, of Moor Park House, Neston Corsham, Wiltshire, 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 releasable retaining means for controlling displacement of an object from a predetermined, position relative to another object and has particular, though not exclusive, application to a door control for holding a door in the open position against the action of a spring or other automatic door closer.

Hospitals, schools, hotels, offices, factories and other like buildings are commonly provided with so called fire doors which, although they may have only a limited resistance to combustion, also serve the purpose of restricting the spread of smoke and/ or the supply of combustion air lin the event of a fire. Because of this latter purpose it is desirable that all fire doors in a building should be closed immediately a fire breaks out even if such doors are remote from the seat of the fire. For this reason, it is preferred that the fire doors be kept shut at all times. However, in praotice, they are frequently wedged open to permit free passage.

The invention provides means which are applicable, inter alma, for retaining fire doors in the open position against the action of the spring or other automatic door closers, with remote control release which can be actuated if a fire is detected.

According ;to the invention, retaining means for controlling displacement of an object from a predetermined position relative to another object comprises a first part for mounting on one of the objects and a second part for mounting on the other object and having a holding member angularly movable between a first position in which it is operative Ito engage with the first part and a second position in which such engagement is inhibited, spring-biasing means for urging the holding member into its second position and pneumatically operated release means operative to displace the holding member into its first position.

The invention will be mere readily understood from the following description of an embodiment thereof with reference to the accompanying drawings, in which: Figure 1 is a plan view of a first part of a door holder in accordance with the, iinven- tion.

Figure 2 is a side view of the part shown in Figure 1, Figure 3 is a front elevational view of a second part of Q door holder in accordance with the invention, and Figure 4 is a cross-sectional view taken on the line lV-IV of Figure 3.

Referring to Figures 1 and 2, the part of the door holder intended to be mounted on the door oompri6es a catch plane 10 having a base portion -11,, adapted to be secured to the door by fixing means passing through a set of holes 12, and a portion 13 projecting at right angles to the base portion 11 and containing a rectangular aperture 14.The edge 15 of the aperture 14 furthest from the base plate 11 serves as a detent surface for engagement with the other part of the door holder as will be explained hereinafter. A pivot ridge 16 is formed centrally on the back of Ithe base portion so that, by adjusting the fixing means extending through the holes 12, the catch .plate 10 can be pivoted about the ridge 16 to provide a limited amount of adjustment of the position of the edge 15.

Figures 3 and 4 show the other part of the door holder which comprises a base member .17 which is adapted to be secured to a wall or other retaining surface by suitable fixing means extending through holes 18 therein. The Ibase member 17 has a recess opening on the side remote from the wall and covered by a .diaphragm 19 to form a chamber 20, the diaphragm 19 being .clamped against the base member 17 by an outer housing member al.The outer hous-ing member 21 is also formed with a recess 22 which is closed by the diaphragm 19 on one side and which communicates -with a through bore 23 on the other. A cylindrical coupling member 24 extends through the bore 23 and has a threaded stud 25 formed on its inner end. The stud 25 extends through a diaphragm stop plate 26, then through the diaphragm 19 and finally through a retaining plate 27. A nut 28 is screwed on to the stud so that the diaphragm 19 is clamped between the diaphragm stop plate 26 and the retaining plate 27 and secured fast with the coupling member 24.The retaining plate 27 engages in a step portion of the periphery of the recess 22 in the outer housing member 21 to prevent the diaphragm 19 from bowing into the recess 22 while allowing it to bow into the chamber 20. However, the extent of travel of this latter bowing action is limited by abutment of the end of the stud 25 with the wall of the chamber 20.

A spring 29 in the recess 22 engages with the .retaining plate 27 to urge the diaphragm 19 and coupling member 24 away from the position shown in Figure 4 so that the end of the stud 25 engages with the wall of the chamber 20. A pneumatic inlet 30 communicates with the chamber 20 so that, by application of air pressure thereto, the diaphragm 19 may be displaced into the position shown lin Figure 4, thereby compressing the spring 29.

The outer end of the cylindrical coupling member 24 has a transverse slot 31 aligned with a corresponding slot 32 in the outer housing member 21. The radially outer ends of the slot 32 are bounded by a bezel ring 33. A shaped latch plate 34 is located in the slots 31 and 32 and pivotally mounted on a pivot pin 35 secured to the outer housing member 21. An operating pin 36, extending across the slot 31 in the coupling member 24, projects through an elongate hole 37 in the latch plate 34 so that axial movement of ;the cylindrical coupling member 24 causes angular movement of the latch plate 34 and vice verso.

The outer end of the latch plate 34 has a hook formation 38 which, when the two parts of the door holder are suitably aligned; can extend into the aperture 14 so as to engage with the edge 15 thereof. When the door is opened, the formation 38 engages with the leading edge 39 of the catch plate 10 so that the latch plate 34 moves in an anti-clockwise direction, as viewed in Figure 4, compressing the spring 29. As soon as the two parts have approached one another sufficiently closely to permit engagement of the formation 318 in the aperture 14, the spring 29 causes the latch plate 34 to move back in the clockwise direction into the position shown in Figure 4.The door is thus retained in the open position but, if it is pulled with a force sufficient to compress the spring 29, the latch plate 34 is displaced in the anti-clockwise direc tion and the holder releases.

In normal use, compressed air is supplied to the chamber 20 by way of the inlet 30 so that the door holder operates as described above. However, it ,the air pressure in the chamber 20 is reduced so that the diaphragm is moved to 'the right, as viewed in Figure 4, by the spring 29, the plate 34 moves in the anti-clockwise direction, thereby releasing the door.

In a building having a number of fire doors equipped with door holders in accordance with the invention the pneumatic inlets 30 of all the door holders may be connected to a common source of compressed air. A pressure of up to 80 lbs./sq.in.

is appropriate for the purpose. Means for releasing the pressure in the connecting pipe work may be associated with the fire alarm system of the building so that when smoke or a fire is detected automatically, or when the alarm is operated manually, the fire doors are closed. Since the presence of air pressure is required to keep the doors open, any fault in the system will cause the doors to close, thereby providing fail-safe opera- tion. In addition, when the building iis not occupied, all the fine doors may be closed by turning off the air pressure.

Th Figure 3, the air dnlet 30 is shown as extending inwardly from the back of the base member 17. This configuration is suitable for use with concealed pipe work. If surface pipe work is to be employed, the air inlet may be provided in one of the side wails of the base member.

As used hereinbefore and in the appended claims, the term "pneumatically operated means" is intended to include not only means operated by air but also means operated by fluids other than air.

WHEAT WE CLAIM IS: 1. Retaining means for controling displacement of an obiect from a predetermined position relative to another object, comprising a first part for mounting on one of the objects and a second part for mounting on the other object and having a holding .member angularly movable between a first position in which it is operative to engage with the first part and a second position in which such engagement is inhibited, spring-biasing means for urging the holding member into its second position and pneumatically operated release means operative to displace the holding member into its first position.

2. Retaining means according to claim 1, wherein the holding member is so arranged that. when it is in its first position, the first pant disengages with the second part On application of a displacing force exceeding a threshold value.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. through bore 23 on the other. A cylindrical coupling member 24 extends through the bore 23 and has a threaded stud 25 formed on its inner end. The stud 25 extends through a diaphragm stop plate 26, then through the diaphragm 19 and finally through a retaining plate 27. A nut 28 is screwed on to the stud so that the diaphragm 19 is clamped between the diaphragm stop plate 26 and the retaining plate 27 and secured fast with the coupling member 24. The retaining plate 27 engages in a step portion of the periphery of the recess 22 in the outer housing member 21 to prevent the diaphragm 19 from bowing into the recess 22 while allowing it to bow into the chamber 20.However, the extent of travel of this latter bowing action is limited by abutment of the end of the stud 25 with the wall of the chamber 20. A spring 29 in the recess 22 engages with the .retaining plate 27 to urge the diaphragm 19 and coupling member 24 away from the position shown in Figure 4 so that the end of the stud 25 engages with the wall of the chamber 20. A pneumatic inlet 30 communicates with the chamber 20 so that, by application of air pressure thereto, the diaphragm 19 may be displaced into the position shown lin Figure 4, thereby compressing the spring 29. The outer end of the cylindrical coupling member 24 has a transverse slot 31 aligned with a corresponding slot 32 in the outer housing member 21. The radially outer ends of the slot 32 are bounded by a bezel ring 33. A shaped latch plate 34 is located in the slots 31 and 32 and pivotally mounted on a pivot pin 35 secured to the outer housing member 21. An operating pin 36, extending across the slot 31 in the coupling member 24, projects through an elongate hole 37 in the latch plate 34 so that axial movement of ;the cylindrical coupling member 24 causes angular movement of the latch plate 34 and vice verso. The outer end of the latch plate 34 has a hook formation 38 which, when the two parts of the door holder are suitably aligned; can extend into the aperture 14 so as to engage with the edge 15 thereof. When the door is opened, the formation 38 engages with the leading edge 39 of the catch plate 10 so that the latch plate 34 moves in an anti-clockwise direction, as viewed in Figure 4, compressing the spring 29. As soon as the two parts have approached one another sufficiently closely to permit engagement of the formation 318 in the aperture 14, the spring 29 causes the latch plate 34 to move back in the clockwise direction into the position shown in Figure 4.The door is thus retained in the open position but, if it is pulled with a force sufficient to compress the spring 29, the latch plate 34 is displaced in the anti-clockwise direc tion and the holder releases. In normal use, compressed air is supplied to the chamber 20 by way of the inlet 30 so that the door holder operates as described above. However, it ,the air pressure in the chamber 20 is reduced so that the diaphragm is moved to 'the right, as viewed in Figure 4, by the spring 29, the plate 34 moves in the anti-clockwise direction, thereby releasing the door. In a building having a number of fire doors equipped with door holders in accordance with the invention the pneumatic inlets 30 of all the door holders may be connected to a common source of compressed air. A pressure of up to 80 lbs./sq.in. is appropriate for the purpose. Means for releasing the pressure in the connecting pipe work may be associated with the fire alarm system of the building so that when smoke or a fire is detected automatically, or when the alarm is operated manually, the fire doors are closed. Since the presence of air pressure is required to keep the doors open, any fault in the system will cause the doors to close, thereby providing fail-safe opera- tion. In addition, when the building iis not occupied, all the fine doors may be closed by turning off the air pressure. Th Figure 3, the air dnlet 30 is shown as extending inwardly from the back of the base member 17. This configuration is suitable for use with concealed pipe work. If surface pipe work is to be employed, the air inlet may be provided in one of the side wails of the base member. As used hereinbefore and in the appended claims, the term "pneumatically operated means" is intended to include not only means operated by air but also means operated by fluids other than air. WHEAT WE CLAIM IS:

1. Retaining means for controling displacement of an obiect from a predetermined position relative to another object, comprising a first part for mounting on one of the objects and a second part for mounting on the other object and having a holding .member angularly movable between a first position in which it is operative to engage with the first part and a second position in which such engagement is inhibited, spring-biasing means for urging the holding member into its second position and pneumatically operated release means operative to displace the holding member into its first position.

3. Retaining means according to claim

1 or 2, wherein the first part comprises a member which cooperates with the holding member to form a spring catch.

4. Retaining means according to claim 1, 2, or 3, wherein the first part has a detent surface and the holding member comprises a plate mounted for angular movement about an axis perpendicular to its surface and having an edge shaped to engage with the detent surface when the plate is in its first position.

5. Retaining means according to claim 4, wherein the release means is adapted to hold the plate in a position in which the detent surface can freely move past the said edge.

6. Retaining means according to any preceding claim, wherein the first part comprises an apertured plate mounted parallel to the direction of relative movement between the first and second part, the detent surface being an edge of the aperture.

7. Retaining means according to any preceding claim, wherein the pneumatically operated release means comprises a chamber, one wall of which is formed by a dia phragm, and a coupling member one end of which is secured b a central region of the diaphragm and the other end of which is connected to the holding member whereby establishment of a pressure differential across the diaphragm causes the holding means to be urged from its second position to its first position.

8. Retaining means for controliing dis- placement of an object from a predetem mined position substantially as hereinbefore described with reference to the accompanying drawings.