What Are Latches and What Are They Used For?
Latches are mechanical devices or fasteners used to hold surfaces together temporarily. For example, they are commonly used to keep doors, cabinets, and gates closed. Large, durable, and reliable latches are used in refrigeration systems, storage facilities, utility boxes, and vehicles such as trucks and trailers in industrial applications. Most latches are formed by assembling or welding die-cast, stamped, or forged metals.
Latches are most useful when they’re applied to the controlled closing and releasing two adjacent surfaces. They are fabricated for a variety of specific functions, including door latching, cabinet latching, gate latching, and paddle latching.
Most often, latches are used in industries such as: furniture, construction, transportation, security, construction and home.
The History of Latches
Latches have been around for a pretty long time. They’re one of older forms of modern hardware. Some of the oldest surviving latches come from 13th century western Europe and 13th century China.
Two of the oldest latch types, the Suffolk latch and Norfolk latch, which were developed in 16th century England and 19th century England, respectively, are still in use today. Of course, because they are not incredibly strong or secure, they’re more used for decorative purposes or whimsy.
For as long as they’ve been in existence, latches have been able to hold doors in a closed position, but not actually lock them. The locking function was left to bolts. Recently, manufacturers have begun making latches that are able to both fasten and lock. Other more recent innovations include the use of electric strike plates, springs, magnetism and more.
Depending on the latch design, manufacturers fabricate latches using die casting, stamping or forging. They may also assemble or spot-weld additional components as needed.
Material choice is an important consideration for latch type. Metal is a high strength material that can withstand repeated use and is resistant to impact. Many latches are required to be heavy duty as they receive tremendous wear due to high frequency and high stress use and so are constructed from different types of metals.
Stainless steel, steel, aluminum alloy, cast iron and brass are all commonly used to make durable and long-lasting latches. Using thermoplastics in the formation of latches offers the added benefits of flexibility and increased shock and impact resistance as plastic materials absorb vibrations better than metals.
Considerations and Customization
When selecting or designing a custom latch for a customer, manufacturers must decide on design factors including: material, mounting design and latching position. The functioning requirements of a hardware industrial latch will be dependent on specifics of its intended use, like: applied force, intensity of operation and potential exposure to environmental elements and weather.
In addition, when selecting a latch type, manufacturers think about both the use and spatial availability of the mounting surface. Some surfaces are more suitable to heavy duty latches than others and it is important that the latch mechanism is not too cumbersome or heavy for the mounting surface to handle. There are a number of different mounting options available for latches.
Concealed mounting refers to the setup in which the latches and corresponding mounting hardware are hidden behind the panel.
Edge mounting installs the latch components along the edge of the mating panels. When the latches are mounted directly on the front of the panel, this is called face mounting.
Side mounting is when both the latch and the keeper are mounted on the back of the connecting panels and cannot be viewed from the cabinet or door front.
Lastly, single-hole mounting involves mounting the latches in a single hole on the panel face.
Latching position is also important. Primary latching position means that the door is securely held in a closed position, while secondary latching position refers to a latch that holds the door in a position that is not fully closed.
Most latches consist of plates or brackets which are placed at corresponding points on two adjacent surfaces. A pin or post is attached to one bracket and the other bracket holds a notch, groove, or seal for the pin to be fed into. Once the pin is joining the brackets of the latch, the door, cabinet, gate or lid cannot be opened.
Types of Latches
The wide range of contexts in which latches are used necessitates a great variety of different industrial design latch types and capabilities. A few are named for their material, while others are named for the objects or mechanisms they hold closed, while still others are named for their parts or how they function.
Stainless steel latches offer high strength and corrosion resistance and are useful in any applications exposed to elements of moisture and high frequency use.
Plastic latches are typically made from high strength thermoplastics and are lightweight latching options which can easily be fabricated for custom design and fit. Other types of latches include compression latches, draw latches, bolt latches, spring latches and slam latches.
Cane Bolt Latches can be considered as larger and more robust barrel bolts. They consist of a rod that fits through a couple of holders. They are usually used in keeping the industrial facilities’ exterior doors and gates opened and closed. When an outdoor gate is closed, the rod is locked into the hole drilled into the surface of the driveway. There can be one more hole drilled in another spot to hold the gate in the open position. This type of bolt requires manual actuation for latching and unlatching. Having a bolt locked into a hole in the floor provides superior strength and an added level of protection.
Bolt latches are one of the simplest latches types. They can be single bolt or double bolt and are typically used on doors and gates.
Spring latches, or spring load latches, are another extremely simple latch. They incorporate an angled bolt edge that engages the spring when the door is closed to secure it. In order to disengage the latch, users turn the handle, which in turn retracts the spring, allowing the door to be opened.
Draw latches, also known as tension or toggle latches, are designed to pull surfaces together and secure them. Consisting of two plates and a joining strap or pin, this type of latch is versatile and can be used in a variety of household and office products such as suitcases and briefcases, trunks, tool and jewelry boxes. They can also be used in corners and hinges. They are also called pull-down latches, over-center fasteners, or toggle clamps. They are commonly used in electronic enclosures and equipment control panels, holding them tightly and securely to protect against dust and water ingress. A draw latch consists of two hooks: a catch and a blade. One of the hooks is attached to a lever. As the latch closes, the hooks clasp each other under tension and merge the two parts. The tight seal created is due to the tension formed when pushing the lever arm results in pulling the drawbar against the catch.
Compression latches are similar to draw latches which form a tight connection, and in addition are often used in applications requiring a seal along the two edges of the adjacent components.
Paddle latches utilize a specific flip-out latch handle mechanism that allows the operator to close the latch tightly and open it when required. Industrial latches are typically large and durable, making them well suited to transportation uses which include latches for the aerospace and automobile industries, as well as for recreational vehicles, railway, marine and off-highway uses.
Slam latches lock when you forcefully shut a door. They are also known as push-to-close latches, and are spring-loaded latches that are more robust in construction than an ordinary spring latch. They automatically lock doors upon closing. The cam rises and turns down behind the wall as the door is pushed, causing the automatic locking of doors when closed. These are best used in high-traffic areas in industrial settings.
Magnetic Latches are ideal for lightweight applications, and mechanical latching is not needed. They are commonly used in the following applications: drawers, HVAC panels, trucks, and trailers. These prevent damage to doors and surrounding structures by securely holding surfaces in place without locking.
SR latches, know more formally as set-reset latches, are a type of flip-flop circuit. Flip-flop circuits exist with two stable states that can be used to store information. Using input and output signals, SR latches lock and unlock digital electronic systems.
Ring latches, or ring gate latches, feature a large ring as a means to lock and unlock it. To unlock it, you simply need to lift and twist the ring. When you set it down, it locks back into place. Mostly, ring latches are used in gardens and backyards, where users are more concerned with atmosphere than security.
T-handle latches are latches used to close and lock doors and lids.
Latch bolts are a common component of front door handles. They work using a spring-loaded bolt at their top edge and a strike plate. When you pull the door closed, the spring bolt will collide with the strike plate, then retract. It will retract until the pressure releases, it fully extends and it locks into the strike plate. In this position, the door will stay closed.
Rim latches work using a surface mounted box and latch that you hook into the doorframe keeper. They have been around since the Colonial age, and as such, they aren’t the most secure, unless you use them in conjunction with a hinge and lock assembly.
Industrial latches are large and tough. Any strong latch used for an industrial, commercial or heavy-duty application can earn this label. Typical industrial latch applications include: marine, railway, automotive, recreational vehicle, aerospace and off-highway.
Lever latches are used to secure overhead bins installed in vehicles like RVs and buses.
Gate latches hold secure the entrances and exits of gated area, such as agricultural fencing, home fencing or high security fencing.
Door latches are used to keep doors closed and secure. A number of different latch types may serve as door latches. Among the most common are: spring latches, latch bolts, dead latches, slam latches and cam locks.
Pawl Latches are known for their large grip range and flexibility of use. They are best suited for applications that require a slide compression fit. They are usually used for locking electrical switchboards, HVAC enclosures, and industrial machinery and equipment.
Trigger Latches have a simple design and functionality. They are commonly used to secure electronic and HVAC enclosures. Pushing the trigger of the lever latch drops down the pawl, causing the door to open. Simultaneously, the level moves upward and can be used as a handle to open the door.
Shutter latches are designed to hold closed window shutters. They have taken many different forms over the years. Today, they’re usually surface mounted strap hinges.
Accessories for Latches
Your latches may come with any number of accessories, depending on its intended application. Examples include: strike plates, handles, hinges, springs, bolt springs, anchors, latch sets, installation kits and tools like screwdrivers.
No one latch is the same, so each installation process is different. Nevertheless, we can offer the following general advice:
Start by placing the latch on the edge of the surface, so where you know where you’re working. Mark the spot if you need to, then set it down again so that you can clean out both the center and interior perimeter of the surface with a chisel. After you’ve done that, make sure that you have chiseled to the correct depth. Finally, you can install your latch. This may involve screwing it in, mounting it or something else entirely. For precise instructions, consult your supplier.
Proper Care for Latches
Latch maintenance is pretty straightforward. With routine cleaning, your latches will continue to work well and look good for years to come. If you have a chrome finished latch, all you need to do is wipe it down from time to time with a damp cloth. If your latch has a clear coat finish, occasionally wash it with a soft buffing cloth and a non-abrasive, mild soap. If your latch has a bronze finish take just a little bit of vegetable oil or just a drop of household detergent, and wipe it with that. You need to be careful with this, since bronze is so sensitive.
Standards for Latches
No matter your application, always make sure that the latch you purchase BHMA (Builders Hardware Manufacturers Association) and ANSI (American National Standards Institute). A stamp from these organizations signifies high quality construction and safety.
The other standard requirements to which your latch should adhere depend on your application and location. For example, many latches must meet ADA (Americans with Disabilities) standards. Find out more by consulting with your industry leaders and applicable governmental offices.
Things to Consider When Purchasing Latches
Before purchasing latches, we recommend you put together a list of your specifications and the latch features you need to consider. Such considerations include: the number of latches you require, intended latch use, intended intensity of performance, the surface on which you will be placing the latch, standard requirements, timeline and budget.
Once you’ve written down everything you need to consider, it’s time to find the right manufacturer. To help you do so, we’ve compiled a list of latch manufacturers in whom we have the utmost confidence. Each one is experienced and reliable. To choose one from among them, peruse their detailed profiles, comparing their available products and services with your specifications list. Narrow down your choices to three or four with services that appear to align most closely with your requirements. Next, call them individually to discuss those requirements. Finally, after you’ve talked to each of them, compare and contrast their answers and make your choice.
Latch Informational Video