Patent Application
20170275918
The present invention relates to door lock mechanisms, and more specifically to mortise style door lock mechanisms with noise reduction features.
Mortise door locks are known in the art and typically include a locking mechanism that is set within the body of a door in a recess or mortise, as opposed to one attached to the door surface. Mortise door locks typically include the combination of a latch, operated by a door knob or lever, and a separate deadbolt mechanism. Some mortise door locks omit the deadbolt mechanism.
Mortise door locks are often used in institutional environments, such as hospitals. Hospitals tend to be busy and loud with many people coming and going from patients rooms at all hours. This makes it difficult for patients to sleep or rest comfortably. Thus, it is desired to reduce noise in hospitals, and one way to do so is by quieting the door lock mechanisms.
It is therefore desired to provide a door lock mechanism, such as a mortise door lock, that achieves a lower noise threshold.
Accordingly, it is an object of the present invention to provide a door lock with additional features to reduce noise.
These and other objectives are achieved by providing a door latch mechanism including a latch housing, a bolt having a proximal end with a head and a distal end having a latch, a hub including a central bore for receiving a spindle, a lever actuated by rotation of the hub, the lever including a slot in a top portion of the lever receiving the head of the bolt such that the lever and the bolt move together in both rearward and forward directions. Further provided is a door or door assembly system including such a door latch mechanism.
The bolt may be slideably mounted in a mount fixed to an interior surface of the latch housing. In some embodiments, there is a first spring around the bolt between the head and the mount and a second spring around the bolt between the mount and the latch. The spring rates may be different from one another. For example, the spring rate of the second spring is greater than the spring rate of the first spring in some embodiments.
In some embodiments, the latch housing includes a rear wall and a front wall, at least one of the rear wall and the front wall including a dampening pad. In some embodiments, the latch mechanism further includes a box mountable within a doorjamb, the box including a magnet positioned adjacent to a distal end of the latch.
The latch may be a three-piece latch with an upper portion, a lower portion, and a center portion where the center portion is the first portion to contact the doorjamb. The center portion may be, for example, a roller element that indexes upon contact between the roller element and the door jam. In some embodiments, the upper and lower portions are metal and the central portion is polymer.
Other objects of the invention and its particular features and advantages will become more apparent from consideration of the following drawings and accompanying detailed description.
The door latch assembly 100 includes an opening 118 for receiving a spindle 120 of the door handle 102 which extends at least partially through the housing 110. The spindle 120 typically has a non-circular cross-section, such as square, to engage within the opening 118 and operate the door latch assembly 100 by rotation. In some embodiments, there is an opening 118 and a spindle 120 on each of the two sides of the housing 110 operating independent of one another.
In a typical design of an entrance lock mechanism, such as a mortise style lock, there is significant noise during actuation. In particular, when the handle 102 or knob is released, the parts slam back into position causing noise. Opening and closing a door having a typical lock mechanism generally results in noise in the range of 95 db. The present invention significantly reduces this noise.
The lever 122 includes a slot 126 that receives a head of the bolt 130. By pairing the hub lever 122 to the head of the bolt 130, they move together in both directions to slow the entire mechanism down and thus reduce noise. The slot 126 also prevents the head of the bolt 130 from hitting the back of the housing 110.
There is a first spring 140 around a distal end of the bolt 130 which acts between the bolt mount 132 and a rear portion of the latch 104. The first spring 140 returns the latch 104 to its original outward position after actuation.
In the present invention, there is also a second spring 142 around a proximal end of the bolt 130. The second spring 142 preferably has a lower stiffness or spring rate than the first spring 140. The second spring 142 acts to slow the return of the bolt 130 after actuation. The second spring 142 also prevents the head of the bolt 130 from impacting the mount 132.
In some embodiments, the present invention includes a soft (e.g., foam) pad 150 fixed to rear panel 113 of the housing 110 to avoid any noise in the event that the lever 122 impacts the housing 110. Another foam pad or gasket 152 is added between the housing 110 and the edge mounting plate 106 providing sound-proofing to capture or dampen any internal noise, keeping it in the case.
In the present embodiment, the latch 104 is a split latch including an upper portion, a center portion 105, and a lower portion. The center portion extends beyond the upper and lower portions in a direction of the door jam and is at least partially rotatable. Thus, when the door 50 closes, the center portion 105 is the first portion to contact the door jam or striking plate. Upon contacting the door jam or striking plate, the center portion 105 rotates in an opposite direction to be in line with the upper and lower portions, after which all three portions recess together into the door latch assembly 100.
The upper and lower portions of the latch 104 are generally made out of metal. The center portion 105 of the latch 104, or the anti-friction element, is made out of a polymer to avoid and/or reduce noise due to the latch hitting the strike as the door closes. In some embodiments, the center portion 105 is comprised of Delrin (acetal homopolymer).
Opening and closing a door having the lock mechanism according to the present invention generally results in noise in the range of 55-60 db, a significant reduction over the typical design. In some embodiments, the noise is further reduced by the hub lever 122 being rigidly connected to, or formed as a single piece with, the hub 124 and/or the retractor assembly 123 to control the return speed of the levers and or knobs.
In the embodiment of
Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many modifications and variations will be ascertainable to those of skill in the art.
| Number | Date | Country | |
|---|---|---|---|
| 62311980 | Mar 2016 | US |
