GB2127086A - Automatic latch for use in scaffolding structures - Google Patents

Abstract

Automatic latch for position engagement of a hook member 2 of a scaffolding structure onto another member 15 of the structure is cranked and has a central pivot portion 6 captive in a vertically elongated aperture 10 of the hook 2, one limb 4 of the latch preventing disengagement of said other member 15 from the hook 2 when the latch drops by gravity to its lowest position in the aperture 10. <IMAGE>

Description

SPECIFICATION Automatic latch for use in scaffolding structures We, Alto Systems Ltd. of 80 Heming road, Washford Industrial Estate, Redditch, in the county of Hereford & Worcester, 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: The invention is concerned with an automatic latch for use in securing the members of a scaffolding structure such that the framework and access platforms of the scaffolding system may be secured against the accidental removal or displacement by the action of wind or other accidentally applied forces.The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view of a scaffolding tubular member together with a platform assembly.

Figure 2 is an end view of the platform assembly as viewed in the direction of arrow 'A' (Fig. 1).

Figures 3, 4, 5 & 6 are side views of the platform assembly illustrating the various modes of operation of the latch mechanism.

The invention comprises of a scaffolding tubular member 15 on to which a hook 2, forming a part of another scaffolding member or scaffolding access platform, is attached. An automatic latch 1 comprising of two metal or plastic rods of circular or other cross-section, which are formed into such a shape and fixed together to appear as a figure of eight when viewed in the direction of arrow 'A' and to appear as an L shape when viewed in the direction of arrow 'B'. The latch is proportioned such that the apertures 16a & 16b may be easily located over the legs 7a & 7b such that member 6 is within the aperture 10.The scaffolding platform or member is then located within the parallel aperture formed between legs 7a & 7b and is securely fixed to item 2 such as to permanently retain item 1 When the scaffolding member 8 is in the horizontal plane, the position of the centre of gravity of the latch 1 is such that members 5 & 6 are in contact with the hook 2 at points 9 & 12 respectively, and member 4 is in the proximity of the tubular member at point 11.

Due to the action of gravity, the latch is located on, and in contact with the scaffold hook at points 9 & BR< 12. lowering of the scaffolding hook onto the tubular member causes the member 4 to be displaced in a horizontal and vertical manner as indicated by arrows C & D, simultaneously raising member 6 vertically in aperture 10 and causing member Sto slide along hook 2 in a direction indicated by arrow 'E'. At the limit of travel, (Fig. 4), the dimension 'x' thus formed is equal to the diameter 'D' of the tube 15 thus permitting the engagement of the hook around the tube. When full engagement has been achieved the locking device returns under gravity to the locked position as shown in figure 5. The dimension 'x' is now smaller than dimension 'D' thus preventing the accidental vertical displacement of the hook.Application of a force to the hook in an upwards direction causes reactionary forces to be applied to the vertical and horizontal faces of the aperture at points 12 and to the curved face of the hook at point 9 in such a magnitude and direction to prevent the release of the locking device.

The latch may be intentionally released by raising the latch vertically thus permitting element 4 to move to the position indicated in Figure 4 thereby releasing the latch.

During the erection and dismantling of the scaffold structure it is desirable to temporarily render the latch inoperative. This is achieved by releasing the latch and then raising member 4 vertically as shown in Figure 6 such that member 4 makes contact with the hook at point 14. This causes member 5 to protrude upwards indicating that the device has been rendered temporarily inoperative. Lowering the hook on to the tube 15 retains the latch in the inoperative mode. The device may be re-engaged to the correct operating mode by raising the hook sufficiently to allow the latch to return to the operating mode by the action of gravity.

The invention also permits the insertion of a spring device within the mechanical assembly such that a similar mode of operation may be performed under the action of spring forces in place of or in addition to gravitational forces.

1. An automatic latch mechanism for use on a scaffolding structure so designed that on lowering the scaffolding hook on to the tubular scaffolding member an automatic locking operation is performed. The forces causing the action of the latch being due solely to gravity.

2. an automatic latch mechanism which may be rendered temporarily inactive such that the components of the scaffolding system may be easily positioned or removed from the structure but may be re-set by raising the scaffolding member a small distance. The re-setting operation thus being automatic and independent of any other mechanical procedures.

3. an automatic latch mechanism as in claim 2 whereby the accidental vertical displacement of the scaffolding component whilst the latch mechanism is in the inoperative mode will automatically re-set the latch by the action of this displacement.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Automatic latch for use in scaffolding structures We, Alto Systems Ltd. of 80 Heming road, Washford Industrial Estate, Redditch, in the county of Hereford & Worcester, 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: The invention is concerned with an automatic latch for use in securing the members of a scaffolding structure such that the framework and access platforms of the scaffolding system may be secured against the accidental removal or displacement by the action of wind or other accidentally applied forces.The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view of a scaffolding tubular member together with a platform assembly. Figure 2 is an end view of the platform assembly as viewed in the direction of arrow 'A' (Fig. 1). Figures 3, 4, 5 & 6 are side views of the platform assembly illustrating the various modes of operation of the latch mechanism. The invention comprises of a scaffolding tubular member 15 on to which a hook 2, forming a part of another scaffolding member or scaffolding access platform, is attached. An automatic latch 1 comprising of two metal or plastic rods of circular or other cross-section, which are formed into such a shape and fixed together to appear as a figure of eight when viewed in the direction of arrow 'A' and to appear as an L shape when viewed in the direction of arrow 'B'. The latch is proportioned such that the apertures 16a & 16b may be easily located over the legs 7a & 7b such that member 6 is within the aperture 10.The scaffolding platform or member is then located within the parallel aperture formed between legs 7a & 7b and is securely fixed to item 2 such as to permanently retain item 1 When the scaffolding member 8 is in the horizontal plane, the position of the centre of gravity of the latch 1 is such that members 5 & 6 are in contact with the hook 2 at points 9 & 12 respectively, and member 4 is in the proximity of the tubular member at point 11. Due to the action of gravity, the latch is located on, and in contact with the scaffold hook at points 9 & BR< 12. lowering of the scaffolding hook onto the tubular member causes the member 4 to be displaced in a horizontal and vertical manner as indicated by arrows C & D, simultaneously raising member 6 vertically in aperture 10 and causing member Sto slide along hook 2 in a direction indicated by arrow 'E'. At the limit of travel, (Fig. 4), the dimension 'x' thus formed is equal to the diameter 'D' of the tube 15 thus permitting the engagement of the hook around the tube. When full engagement has been achieved the locking device returns under gravity to the locked position as shown in figure 5. The dimension 'x' is now smaller than dimension 'D' thus preventing the accidental vertical displacement of the hook.Application of a force to the hook in an upwards direction causes reactionary forces to be applied to the vertical and horizontal faces of the aperture at points 12 and to the curved face of the hook at point 9 in such a magnitude and direction to prevent the release of the locking device. The latch may be intentionally released by raising the latch vertically thus permitting element 4 to move to the position indicated in Figure 4 thereby releasing the latch. During the erection and dismantling of the scaffold structure it is desirable to temporarily render the latch inoperative. This is achieved by releasing the latch and then raising member 4 vertically as shown in Figure 6 such that member 4 makes contact with the hook at point 14. This causes member 5 to protrude upwards indicating that the device has been rendered temporarily inoperative. Lowering the hook on to the tube 15 retains the latch in the inoperative mode. The device may be re-engaged to the correct operating mode by raising the hook sufficiently to allow the latch to return to the operating mode by the action of gravity. The invention also permits the insertion of a spring device within the mechanical assembly such that a similar mode of operation may be performed under the action of spring forces in place of or in addition to gravitational forces. CLAIMS

1. An automatic latch mechanism for use on a scaffolding structure so designed that on lowering the scaffolding hook on to the tubular scaffolding member an automatic locking operation is performed. The forces causing the action of the latch being due solely to gravity.

2. an automatic latch mechanism which may be rendered temporarily inactive such that the components of the scaffolding system may be easily positioned or removed from the structure but may be re-set by raising the scaffolding member a small distance. The re-setting operation thus being automatic and independent of any other mechanical procedures.

3. an automatic latch mechanism as in claim 2 whereby the accidental vertical displacement of the scaffolding component whilst the latch mechanism is in the inoperative mode will automatically re-set the latch by the action of this displacement.