GB2416115A

GB2416115A - Turnable lever for door bolt mechanism

Info

Publication number: GB2416115A
Application number: GB0415694A
Authority: GB
Inventors: Alan Waith
Original assignee: B M Ltd
Current assignee: B M Ltd
Priority date: 2004-07-14
Filing date: 2004-07-14
Publication date: 2006-01-18
Anticipated expiration: 2024-07-14
Also published as: GB0415694D0; GB2416115B

Abstract

A turnable lever 110 for a door bolt mechanism 134 comprises a barrel portion 112 configured to engage the bolt mechanism such that the lever may be used to lock and unlock the bolt, and first and second arms arranged on the barrel portion, the first arm 114 being longer than the second arm 116.

Description

Turn for a Door Lock Mechanism The invention relates to a turn for a door

lock mechanism, and particularly, but not exclusively, for use in hospitals, care homes, and the like by less abled bodied persons.

Typically, hospitals, care homes and other establishments which cater for the ill, infirmed, elderly or less abled bodied individuals must ensure that the surroundings are ergonomically suited to the individual's health needs. For example, it must be ensured that door furniture (door handles, door locks, etc.) is operable by persons having illnesses which lead to debilitation of the motor skills in the hands and arms, such as arthritis. In such a case, it is imperative that door handles and door locks are operable with a clenched fist, since a patient with limited use of the hands will not necessarily have sufficient dexterity in the fingers to operate certain known types of door handle or lock.

Whilst various solutions to this problem have been proposed, the usability of these solutions by the more abled bodied user is often impaired by the size or configuration of such door locks. For example, turns having a single long arm are known, but these force more abled bodied users to adapt the way in which they normally operate the turn, which can be inconvenient.

It is therefore an object of this invention to provide a turn for a door lock which is operable by persons having limited digital dexterity whilst not impairing use by the more abled body user.

According to the invention there is provided a turn for a door lock mechanism, the turn having a barrel portion configured to engage a part of the lock mechanism so that the turn is operable to lock and unlock the lock mechanism, the turn further comprising first and second arms arranged on the barrel portion, wherein the first arm is longer than the second arm.

Advantageously, the provision of arms of differing lengths allows the turn to be operated equally effectively by persons having limited dexterity in the hands and fingers as those having a normal level of dexterity. Those of limited dexterity are able to operate the longer arm whilst those of normal dexterity are able to operate both the shorter and the longer arm in a manner akin to more conventional lock turns.

The invention will now be described, by way of example only, by reference to the following figures, in which: Figure l is a side view of the turn of the current invention showing hidden detail, Figure 2 is plan view of the turn of figure I showing hidden detail, Figure 3 is a front view of the turn of figure l, Figure 4 is an isometric view of a part of a door showing the latch mechanism of the current invention.

In figure l a door lock turn 10 is shown having a barrel portion 12, a first arm 14 and a second arm 16. The first and second arms 14, 16 are defined by a rod 18 which is received transversely by the barrel portion 12 by means of through hole 20. In alternative embodiments the entire turn is integrally moulded or each arm is separately attached to the barrel.

As shown in figures 2 and 3 the barrel portion 12 and the first and second arms 14, 16 are of circular cross-section. It is, however, conceivable that the barrel portion 12 and first and second arms 14, 16 have a cross-section other than circular, for example square, hexagonal or other polygonal shape or be oval. The ends 14A, 16A of the first and second arms 14, 16 have a bevelled profile, to soften the feel of the turn in the hands of the user. Equally, the bevelled ends of the barrel portion 12 and first and second arms 14, 16 could be chamfered or square.

Referring again to figures l and 2, the barrel portion 12 defines a cavity 22 for receiving a part of a lock mechanism which projects out of the door and turns to operate the lock (not shown for clarity). The turn 10 is mounted on the lock mechanism so as to be rotatable about an axis of rotation 24 through 360 degrees in order to lock and unlock the lock mechanism.

The cavity 22 may be adapted to receive, for example, a screw thread, a spline, a slot and groove, or other means of rotatably fixing the turn to the lock mechanism. Equally, the cavity 22 may be adapted to fit over a key or conventional door lock turn. In this particular embodiment the barrel portion 12 has a threaded bore 24 into which is inserted a grub screw (not shown for clarity) for engaging the lock mechanism so that rotation of the turn locks and unlocks the lock mechanism, and the turn is held on.

It will be appreciated from the figures that the first arm 14 is longer than the second arm 16. The length of each arm is considered to be distance along its exposed portion (i.e. from where it emerges from the barrel) to the end 14A, 16A of the first or second arm 14, 16, respectively. In this particular embodiment the first arm 14 is approximately two and a half times as long as the second arm 16. However, it is perfectly conceivable within the scope of the invention that the first arm 114 is anything between 1.5 and 3.5 times the length of the second arm 116, preferably 2 to 3 times the length. The purpose of this feature of the invention will be described in further detail shortly.

In the specific embodiment depicted in the accompanying figures the first arm 14 has a length of 41mm, the second arm 16 having a length of 16mm. It is conceivable within the scope of the invention that the length of second arm 16 can range between lOmm and 20mm in length, preferably 12mm to 18mm. The first arm may range between 25mm and 70mm, preferably 35mm to 50mm. These ranges have been found to achieve a good balance between ease of operation with a lock exhibiting a typical torque requirement to switch between locked and unlocked states, and economy of material used to make the turn.

With reference now to figure 4, in which features common with figures 1 to 3 are numbered lOO greater, a latch assembly 100 is seen mounted on a door 102 (of which only part is shown). The latch assembly 100 includes, on a first side 102A of the door 102, a lock turn l 10, a release handle 130 and a front piece 132. Arranged on an endface 102B of the door 102 is a deadlock 134 which is operable between an unlocked position (as shown in figure 4) and a lock position by the turn 110, and a latch bolt 136 operable to release the door by the release handle 130.

In use, the operator is able to release the door 102 by operating the release handle 130 in a known manner. The release handle is shaped such that a person with limited dexterity in the hand is able to operate the handle. Even those with no dexterity in the fingers are able to operate the handle by forming a clenched fist.

The provision of a door turn 110 having a first arm 114 which is approximately 2.5 times the length of the second arm 16 allows different users to operate the lock turn in a different manner. Those having a normal level of dexterity in the hands and fingers are able to contact both arms 114, 116, in a manner similar to a conventional turn having two shorter arms. It would be appreciated that the presence of a longer first arm 1 14 does not in any way impede the standard user from operating the lock.

However, a person of limited dexterity is able to operate the turn 110 by means of the longer first arm 114 only, by using a clenched fist. This feature provides a distinct advantage over known lock turns which do not allow a person of limited dexterity to generate sufficient moment in the turn to unlock the lock mechanism.

It will be noted from figure 4 that the release handle 130 and the lock turn 110 are separated by a distance X. This distance X is sufficient to allow rotation of the first lock arm 114 without impinging on the release handle 130. A preferred minimum for distance X is 72mm.

It will be appreciated that the ratio of arm lengths of 2.5 to 1 is chosen by way of example only. In practice, a smaller, or greater, ratio may be employed, for example between 1.5 and 3.5, without excessively impeding the performance of the turn.

The turn may be made from a variety of materials such as brass, satin chrome or stainless steel, the prime consideration being the matching of the material and surface finish to that of the complete latch assembly.

Claims

Claims 1. A turn for a door lock mechanism, the turn having a barrel

portion configured to engage a part of the lock mechanism so that the turn is operable to lock and unlock the lock mechanism, the turn further comprising first and second arms arranged on the barrel portion, wherein the first arm is longer than the second arm.
2. The turn according to claim I, wherein a ratio of the lengths of the first arm and second arm is between 1.5:1 and 3.5:1.
3. The turn according to claim 2 wherein the ratio is between 3:1 and 2:1 minimum and maximum lengths.
4. The turn according to any preceding claim wherein the length of the second arm is between lOmm and 20mm and the length of the first arm is between 25mm and 70mm.
5. The turn according to any preceding claim wherein the first and second arms are arranged on directly opposite sides of the barrel portion.
6. The turn according to any preceding claim wherein the first, or second arm, is substantially circular in cross-section.
7. The turn according to any preceding claim wherein the first and second arm are of substantially circular in cross-section.
8. The turn according to any preceding claim wherein the barrel portion is substantially circular in cross-section.
9. A door latch mechanism including a manual door release element and a turn according to any preceding claim, wherein the release element and the turn are sufficiently separated to allow free rotation of the turn and free passage in use of a hand of an operator between the release element and the turn.