GB2214975A - Door fastening - Google Patents

Abstract

The fastening comprises a lever arm 5 which in a first position will hold closed a door to which it is applied and by rotation of the lever arm 5 to a second position will allow the door to be opened outwardly; the fastening includes means, to cause, in an emergency, the lever arm 5 to collapse relative to a main body portion when the lever arm 5 is in the said first position, under the action of an applied force producing a torque of predetermined magnitude. As shown, the lever arm 5 is rotatable about a horizontal axis (H, Figure 2) for movement between first and second positions and is rotatable about a vertical axis V to allow the collapse of lever arm S. In figure 1-5 balls or plungers 7a, 7b acted on by compression spring 8 are moved out of recesses (5a, 5b, Figure 5) to allow the collapse. In figures 6-9, the torque causes a nose 17b of a leaf spring 17 to ride over ridge 12c of a pivot block portion 12. <IMAGE>

Description

Collapsible Turnbuckle Door Catch The present invention is concerned with a turnbuckle door catch provided with a lever arm which allows a door to be kept in a closed position, whilst providing a means for allowing the door to be pushed open from inside a room or cabin under emergency conditions that could arise in the event of an accident such as fire or an escape of gas fumes etc. by allowing the controlled collapse of the lever arm.

In accordance with this invention there is provided a turnbuckle door catch comprising a lever arm which in a first position will hold closed a door to which it is applied and by rotation of the lever arm to a second position will allow the door to be opened outwardly, the catch including means to cause, in the event of an emergency, the lever arm to collapse, when the lever arm is in the said first position, under the action of an applied force producing a torque of predetermined magnitude. Preferably the means causing the lever arm to collapse in the event of an emergency will cause the lever arm to rotate about an axis perpendicular to the axis about which the lever arm rotates in moving between the said first and second positions. The means causing the lever arm to collapse may be actuable by compression of a spring or may be actuable by deflection of a leaf spring.

By way of example, two embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a side view of a first embodiment of collapsible turnbuckle door catch, Figure 2 is a front view of the catch shown in Figure 1, Figure 3 is a cross-section on the line A-A of Figure 1, Figure 4 is a cross-section on the line B-B of Figure 1, Figure 5 is a cross-section on line C-C of Figure of part of the catch shown, Figure 6 is a side view of a second view of a second embodiment of collapsible turnbuckle door catch, Figure 7 is a first view of the catch shown in Figure 6, Figure 8 is a cross section on the line A-A of Figure 6, and Figure 9 is a cross section on the line B-E of Figures 6 and 8.

Essentially Figures 1 to 5 of the drawings show a catch lever arm 5 rotatable in two different planes, i.e.

900 clockwise to 900 anticlockwise about a horizontal axis for normal operation of securing and releasing a door as shown in Figure 2, and also 900 about a vertical axis allowing collapse of the lever arm 5 as shown in Figure 1.

A main body portion 2 is attached to a base 1 by a rivet 3. The rivet 3 has a head 3a which has a sufficiently large diameter to shroud a base spigot la about which the main body portion 2 is rotatable on the base 1 and which also captivates a compression spring 4.

The upper surface of the base 1 is provided with a number of "V" valleys ib into which a corresponding number of 'V" hills 2a provided in the main body portion 2 are located, when the main body portion 2 is in its initial or final rotary position by rotation. The compression spring 4 induces a force via the rivet 3 between the base 1 and the main body portion 2 forcing the "V" hills 2a into the "V" valleys ib thus creating relatively light resistance to rotation about a horizontal axis H as shown in Figure 2 and preventing the main body portion 2 from moving from its initial or final rotary position until a determined manually applied light torque is given via the lever arm 5 to the main body portion 2.

The lever arm 5 is mounted on the main body portion 2, the lever arm 5 being captivated by the provision of a rivet shaft 6 allowing rotary movement of the lever arm 5 about a vertical axis V (as shown in Figure 1) to take place relative to the main axis. Two balls or plungers 7a and 7b together with a compression spring are housed in the main body portion 2 away from the centre or rotation. The two balls or plungers 7a and 7b are freed via the compression spring 8 outwards, towards, and into recesses or wells 5a and 5b within lever arm 5.This has the effect of causing resistance to rotation about the vertical axis when the lower arm 5 is in its usual position relative to the main body portion 2 until a torque of certain magnitude tangential to the vertical axis is reached, causing the two balls or plungers 7a, 7b to ride out of the recesses or wells 5a, 5b and to move inwardly towards each other, causing further compression of the spring 8 and thus allowing the lever arm 5 relative to the main body portion 2 to collapse and move about the vertical axis V.

Essentially Figures 6 to 9 of the drawings show a catch lever arm 15 rotatable in two different planes, i.e. 900 clockwise to 900 anticlockwise about a horizontal axis H for normal operation of securing and releasing a door as shown in Figure 7, and also approximately 650 about a vertical axis V allowing collapse of the lever arm 15 as shown in Figure 6.

Referring to Figure 8 a pivot block portion 12 is attached to a base 11 by a rivet 13. The rivet 13 has a head 13a which has a sufficiently large diameter to shroud a base spigot lia about which the pivot block portion 12 is rotatable on the base 11 and which also captivates a compression spring 14 and plunger 16 in hole 12e. The upper surface of the base 11 is provided with a number of "V" valleys or spherical recesses lib into which plunger 16 locates, when the pivot block portion 12 is in its initial or final rotary position by rotation.

The compression spring 14 induces a force to be applied to plunger 16, pressing nose 16a of the plunger into the "V" valleys or spherical recesses lib thus creating relatively light resistance to rotation about a horizontal axis H as shown in Figure 7 and preventing the pivot block portion 12 from moving from its initial or final rotary position until a determined manually applied light torque is given via lever arm 15 to the pivot block portion 12.

The lever arm 15 is mounted between the pivot block portion 12, and the base 11. Two lugs 15a and 15b on lever arm 15 being captivated into 'U' undercuts 12a and 12b on pivot block portion 12 allow rotary movement of the lever arm 15 about a vertical axis V (as shown in Figure 6) to take place relative to the main axis.A leaf spring 17 is attached to underside face 15c of the lever arm 15 by a riveted spigot 15d, passing through a hole 17a in the leaf spring 17, sandwiching leaf spring 17 between one or two washers 18, and the underside face 15c of lever arm 15, whilst nose 17b of the leaf spring 17 is tucked under ridge 12c of the pivot block portion 12 causing resistance to rotation about the vertical axis V, when the lever arm 15 is in its usual position relative to the pivot block portion 12, until a torque of a certain magnitude, tangential to the vertical axis V is reached, causing the nose 17b of the leaf spring 17 to ride over ridge 12c of the pivot block portion 12, until the leaf spring nose 17b is completely over the ridge 12c and into a stress free condition, allowing completely free movement of the lever arm 15 around the vertical axis V.

The lever arm 15 can be returned to its normal operating position by applying a torque in the opposite direction, making the leaf spring nose 17b ride on curved inclined face 12d of pivot block portion 12, until the leaf spring nose 17b clicks over the pivot block portion ridge 12c to its normal position.

Claims (6)

1. A turnbuckle door catch comprising a lever arm which in a first position will hold closed a door to which it is applied and by rotation of the lever arm to a second position will allow the door to be opened outwardly, the catch including means to cause, in the event of an emergency, the lever arm to collapse, when the lever arm is in the said position, under the action of an applied force producing a torque of predetermined magnitude.

2. A catch according to Claim 1, wherein the means causing the lever arm to collapse in the event of an emergency will cause the lever arm to rotate about an axis perpendicular to the axis about which the lever arm rotates in moving between the said first and second positions.

3. A catch according to Claim 1 or Claim 2, wherein the means causing the lever arm to collapse are actuable by compression of a spring.

4. A catch spring according to Claim 1 or Claim 2, wherein the means causing the lever arm to collapse are actuable by deflection of a leaf spring.

5. A turnbuckle door catch substantially as herein described with reference to Figures 1 to 5 of the accompanying drawings.

6. A turnbuckle door catch substantially as herein described with reference to Figures 6 to 9 of the accompanying drawings.