GB2236139A

GB2236139A - A magnetic lock and its method of installation

Info

Publication number: GB2236139A
Application number: GB8919774A
Authority: GB
Inventors: Desmond Ryan
Original assignee: Abloy Security Hardware Ltd; Warshaw; WARSHAW
Current assignee: Abloy Security Hardware Ltd; Warshaw; WARSHAW; Assa Abloy Ltd
Priority date: 1989-09-01
Filing date: 1989-09-01
Publication date: 1991-03-27
Anticipated expiration: 2009-09-01
Also published as: GB8919774D0; GB2236139B

Abstract

A horizontal transom (4) of a door frame is arranged to support a housing (6) of a magnetic lock of the invention. This housing (6) houses at least one electromagnet (8) whose poles are provided in a magnet face (10). An armature (12) is fixed to the door (2), and in the closed position of the door (2), the armature (12) is in contact with the magnetic face (10). The housing (6) has a mounting plate (16) which projects beyond the magnet face (10). When the mounting plate (16) abuts the door (12), the magnet housing and the electromagnet (8) are correctly positioned relative to the door (2) and armature (12), whereby the mounting plate (16) serves as a template during installation. <IMAGE>

Description

A MAGNETIC LOCK AND ITS METHOD OF INSTALLATION The present invention relates to a magnetic lock and its method of installation.

Magnetic locks, for example, for holding a door securely fastened, are known. Such a lock comprises an electromagnet fixed to one of the door frame and door, and an armature fixed to the other of the door and door frame and arranged when the door is closed to be in contact with the electromagnet. It will therefore be appreciated that if the electromagnet is energised when the door is closed it will create a powerful magnetic field travelling through the armature which will hold the door securely fastened.

For a magnetic lock to work effectively, it is essential that it be installed such that the armature is exactly aligned with the magnet surface and makes complete contact with the magnet surface in the closed position. Because of this, paper templates and dead reckoning are currently used by installers fixing such magnetic locks in position. Clearly this causes some difficulty in installation.

It is an object of the invention to provide a magnetic lock designed to reduce such installation difficulties.

According to a first aspect of the present invention there is provided a magnetic lock arranged to hold a hinged closure member in a position closing an opening, said magnetic lock comprising a housing arranged to be fixed to the perimeter of said opening, and an electromagnet carried by said housing to define a magnet face on one side of said housing, the magnetic lock further comprising a metal plate arranged to be fixed to said closure member and arranged to form an armature for said electromagnet, wherein in use the housing and the plate are positioned such that in the closed position of the closure member the plate and said magnet face are in contact, and wherein said housing has an extended mounting plate at a side thereof adjacent to said one side on which the magnet face is defined, said mounting plate projecting beyond said magnet face and being arranged to serve as a template when the housing is fixed to the perimeter of said opening.

In use, the housing is fixed to the perimeter of the opening, for example to a door frame, at a position such that the closure member, for example a door, abuts against the projecting mounting plate. In this respect, the mounting plate serves as a template and determines accurately the position of the housing.

In a preferred embodiment the mounting plate is also used to fix the housing to the perimeter of the opening.

Preferably, the housing is hollow and is arranged to house wires for supplying electricity to the electromagnet. These wires are preferably comprised in an extensible cord, for example in a curly cord.

In a preferred embodiment, the housing is rectangular in cross-section and the two opposed sides adjacent to said one side on which the magnet face is defined are each provided with fixing means arranged to fix the mounting plate thereon. The mounting plate can therefore selectively be fixed, by way of said fixing means, on either of said two opposed sides of the housing. This enables the same housing and mounting plate to be utilised irrespective of the direction of opening of the closure member. Preferably, the transverse extent of the mounting plate is greater than the corresponding transverse extent of either of the two opposed sides such that the mounting plate can be fixed to the selected side to extend substantially over the whole transverse extent of the side and still project beyond the magnet face.

In a preferred embodiment, the magnet is constructed of laminations potted in epoxy and received in a cavity provided therefor in said one side of the housing such that the magnet is housed within the housing and the magnet face extends along said one side.

A plurality of the electromagnets may be mounted in the housing with their magnet faces substantially aligned or a single such magnet may be provided. The magnet can be secured in position by any appropriate means.

The armature is preferably of chrome plated, soft, magnetic steel which is fixed to the closure member by a fixing bolt, preferably including flexible mounting.

Although the magnetic lock may be used in any circumstances where a hinged closure member is to be held in a position closing an opening, the magnetic lock is particularly useful for locking doors. In this respect, the armature is affixed to the door itself.

The housing is fixed to a suitable part of the door frame and clearly may be arranged to extend either vertically or horizontally.

In a preferred embodiment, the housing is arranged to extend horizontally and is fixed to the transom.

Preferably, the magnet housing extends the full width of the door opening.

The invention also extends to a method of installing a magnetic lock as defined in any of the paragraphs set out above, the method comprising, with the closure member in its closed position, abutting the mounting plate against the closure member to determine the fixing position for said housing, and then fixing the housing to the perimeter of said opening.

The electromagnet is preferably provided with electric supply wires in an extensible cord such that the housing incorporating the electromagnet or electromagnets can be suitably supported whilst the necessary electrical connections are made. The extensible cord is received within the housing.

Embodiments of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically a first embodiment of a magnetic lock fixed in position to maintain a door in its closed position, Figure 2 shows a front elevation of a second embodiment of a housing with an electromagnet of a magnetic lock of the invention, Figure 3 shows a side elevation of the housing of Figure 2, and Figure 4 shows an end elevation of the housing of Figures 2 and 3.

Figure 1 shows a magnetic lock of the invention arranged to hold a door 2 in a closed position. In this respect, in conventional manner the door is hinged to close a door opening which is surrounded by a door frame. A transom 4, which extends substantially horizontally, of the door frame is arranged to support a housing 6 of the magnetic lock. This housing, which for example is of extruded aluminium is arranged to extend the full width of the door opening and of the transom 4 and houses at least one electromagnet 8. The poles of the electromagnet are provided in a magnet face generally referenced 10.

Generally, one or more electromagnets 8 would be provided in the housing 6 spaced along the length thereof. The magnet face or faces 10 face the door 2.

An armature in the form of a plate 12 of soft magnetic material is fixed to the door 2 by way of a fixing bolt 14. For example, the armature plate may be made of chrome plated, soft, magnetic steel.

In the closed position of the door 2, which is illustrated in Figure 1, the plate 12 has to be aligned with and in contact with the magnet face 10. It will be appreciated that energisation of the electromagnet 8 will then hold the armature 12 firmly against the magnet face 10 such that opening of the door is prevented.

In the embodiment shown in Figure 1, the housing 6 has a substantially U-shaped cross-section with one limb 16 thereof acting as a mounting plate for fixing the magnet housing 6 to the transom 4. However, it will be seen that the mounting plate 16, which is on a side of the housing 6 adjacent to the magnet face 10, projects beyond the magnet face 10. In this respect, it will be seen that the projection of the mounting plate 16 is arranged such that when the mounting plate 16 abuts the door 2 the magnet housing and the electromagnet 8 carried thereby are correctly positioned relative to the door 2 and relative to the armature 12 carried thereby.

It will be appreciated that when the magnet housing 6 is being installed the projection of the mounting plate 16 can be used to determine the exact position of the magnet housing 6 relative to the transom 4. When that position has been determined the housing 6 is fixed in position, for example by way of fixing screws, as 18.

Figures 2, 3 and 4 show an alternative embodiment of a magnet housing which can be installed irrespective of the direction of the door opening. The magnet housing 20 shown in Figures 2, 3 and 4 is hollow and has a substantially rectangular cross-section. The front wall 22 of the housing 20 is formed with one or more cavities 24 therein in which an electromagnet indicated at 26 is received. This electromagnet preferably comprises a stack of thin E-shaped laminations with appropriate windings arranged to define three poles 28 in a magnet face thereof. The lamination stack is potted in epoxy and is received within the housing 20 through the cavity 24 and is suitably secured in position, for example, by adhesion.The housing 20 has two opposed side walls 30 which are each adjacent the front wall 22, and are each provided with a series of fixing holes 32 for enabling a mounting plate 34 to be affixed thereto. It will be seen that the longitudinal extent of the mounting plate 34 is substantially the same as the longitudinal extent of the housing 20, but, as is clearly shown in Figure 4, the transverse extent of the mounting plate 34 is greater than the transverse extent of each side wall 30.

In use, the mounting plate 34 is mounted to a transom of a door frame as previously such that the projecting end of the mounting plate 34 abuts the door.

The housing 20 is then attached by way of the fixing holes 32 and appropriate screws (not shown) which extend through the holes 32 in both side walls 30 of the housing and into tapped holes (not shown) in the mounting plate 34. It will be appreciated that the side wall 30 which abuts the mounting plate 34 will depend upon the direction of door opening. In this way the magnet housing 20 is correctly positioned relative to both the door frame and the door. A soft metal armature (not shown), is then fixed to the door in the appropriate position. Again, the fixed magnet housing can be used to establish the position for the armature.

The or each electromagnet 26 then has to be connected to an electricity supply. In this respect, the electrical wires leading to the electromagnet 26 are provided in an extensible cord, for example a curly cord 36 which is passed through a cavity 24 to extend within the housing 20, and its free end is then connected to an appropriate terminal block. Because the cord 36 is extensible, this connection can be made with the housing 20, incorporating the electromagnet, appropriately supported near by.

It will be appreciated that variations to and modifications of the present invention can be made within the scope of the present application.

Claims

1. A magnetic lock arranged to hold a hinged closure member in a position closing an opening, said magnetic lock comprising a housing arranged to be fixed to the perimeter of said opening, and an electromagnet carried by said housing to define a magnet face on one side of said housing, the magnetic lock further comprising a metal plate arranged to be fixed to said closure member and arranged to form an armature for said electromagnet, wherein in use the housing and the plate are positioned such that in the closed position of the closure member the plate and said magnet face are in contact, and wherein said housing has an extended mounting plate at a side thereof adjacent to said one side on which the magnet face is defined, said mounting plate projecting beyond said magnet face and being arranged to serve as a template when the housing is fixed to the perimeter of said opening.

2. A magnetic lock as claimed in Claim 1, wherein said housing is fixed to the perimeter of the opening atç position such that the closure member abuts -against -th'-e projecting mounting plate, whereby the mounting plate serves as a template and determines accurately the position of the housing.

3. A magnetic lock as claimed in Claim 1 or 2, wherein said mounting plate is also used to fix the housing to the perimeter of the opening.

4. A magnetic lock as claimed in any preceding claim, wherein the housing is hollow and is arranged to house wires for supplying electricity to the electromagnet.

5. A magnetic lock as claimed in any preceding claim, wherein the housing is rectangular in cross-section and two opposed sides thereof adjacent to said one side on which the magnet face is defined are each provided with fixing means arranged to fix the mounting plate thereon.

6. A magnetic lock as claimed in Claim 5, wherein the transverse extent of the mounting plate is greater than the corresponding transverse extent of either of said two opposed sides such that the mounting plate can be fixed to the selected side to extend substantially over the whole transverse extent of the side and still project beyond the magnet face.

7. A magnetic lock as claimed in any preceding claim, wherein the magnet is constructed of laminations potted in epoxy and received in a cavity provided therefor in said one side of the housing such that the magnet is housed within the housing and the magnet face extends along said one side.

8. A magnetic lock as claimed in any preceding claim, wherein a plurality of electromagnets are mounted in the housing with their magnet faces substantially aligned.

9. A magnetic lock as claimed in any preceding claim, wherein said armature is of chrome plated, soft, magnetic steel which is fixed to the closure member.

10. A magnetic lock as claimed in Claim 9, wherein said armature is fixed to the closure member by a fixing bolt, preferably including flexible mounting means.

11. A magnetic lock as claimed in any preceding claim, wherein the housing is fixed to a door frame and said armature is fixed to the door.

12. A magnetic lock as claimed in Claim 11, wherein said housing is fixed to a suitable part of the door frame and is arranged to extend either vertically or horizontally.

13. A magnetic lock as claimed in Claim 12, wherein the housing is arranged to extend horizontally and is fixed to the transom, and wherein the magnet housing extends substantially the full width of the door opening.

14. A method of installing a magnetic lock as claimed in any preceding claim, the method comprising, with the closure member in its closed position, abutting the mounting plate against the closure member to determine the fixing position for said housing, and then fixing the housing to the perimeter of said opening.

15. A magnetic lock arrangedto hold a hinged closure member in a position closing an opening substantially as hereinbefore described with re-ferenc & t6th'e- accompanying drawings.

16. A method of installing a magnetic lock substantially as hereinbefore described with reference to the accompanying drawings.