10 Years Ago
In his April SHDA Report, IDN’s Arnie Goldman reflected on the loss of eight “Legends of the Lock Industry” in 2011: Al Hoffman (H. Hoffman Co.), Andy Hildebrand (Blaydes Lock and Security), Doug Maston (KSP), Larry Kern (ASSA ABLOY), Ernie Pugatch (Arrow Lock), Ed Mayer (Commonwealth Lock), Sid Schwartz (Security Lock Distributors) and Jerry Hoffman (HPC). Our Know Your Distributors guide included a long list of distributors, most of which still serve the locksmith marketplace today and a few that since have closed or been acquired by larger companies. Jerry Levine wrote a how-to article on opening mechanical safe locks by manipulation. Tim O’Leary wrote about the versatile new HES 9000 series electric strikes. An article titled “Electric Strikes: How, Where and Why?” provided an overview. The Norton SafeZone Multi-Point Electromechanical Closer/Holder also was featured. Tim O’Leary reported on high-definition video surveillance, a technology that’s grown by leaps and bounds over the past 10 years.
20 Years Ago
The April 2001 Locksmith Ledger issue was dedicated to the many fine distributors regularly serving the locksmith community. Wade Landrum explained the virtues of ADI distributors. Wade Landrum also discovered a new Nanolock made by Encrypta. Mike Groover showed us the IDN-West facilities in Los Angeles, while locksmith Mike Ferrill visited the Stone & Berg offices in New England. Readers service-card inquiry totals were used to choose the 20 top locksmith company picks for the year 2000. Topping the list were names such as Ilco Unican, Schlage, Master Lock, STRATTEC and Major Manufacturing. Jerry Levine found a Chrysler concept car at the Detroit Auto Show that used a driver fingerprint-verification security system. Biometric door locks now are offered on some luxury vehicles. Tom Appel tested the Pro-Lok mortising tool. Jerry Levine installed a ROFU electric strike on an outside gate. Charles Stephenson completed his series on combination lock servicing. John Grist told of his interest in antique lock collecting and provided addresses for more information about the hobby
Door Closers, Adjusting for Change
Read the full article from April 2011 at www.locksmithledger.com/10290157
Simplified, a door closer is a spring-loaded, adjustable hydraulic system, and through the use of specifically located valves, it’s capable of safely closing and latching a door by using only the power provided by the person who opened the door. When a person opens a door, the closer spring compresses, and the hydraulic fluid moves away from the compressing spring. As the door closes, the spring expands, and the fluid is forced into the area of the expanding spring. Valves positioned along the closer body determine how fast the fluid moves as the spring expands.
The process of opening and closing a door equipped with a mechanical door closer can be divided into four or five stages.
The first stage is when the person swings open the door. Depending upon the obstructions within the swinging area, the door might be able to be opened slightly more than 100 degrees (providing sufficient room for traffic flow) to fully open, up to 180 degrees. The opening also can vary by the type of closer arm installed.
The second stage is the backcheck when a special valve in most door closers controls the opening swing. The door then slows smoothly prior to the end of the swing.
Note: A solid stop always should be installed, because the closer’s backcheck never was designed to be a doorstop. Without a solid doorstop, additional pressure is exerted against the mounting screws, and the spindle, arms and shoe or foot shortening the operational life expectancy of the door closer.
The additional stage is Delayed Action, an available feature on many door closers. Delayed Action holds the door fully open for a minimum number of seconds, providing additional time for passage through the doorway. If the door closer is equipped with a delayed-action valve, the door will stay in the open position for an adjustable amount of time. For high-traffic doorways, holding the door open increases traffic flow.
The next stage is the closing speed that controls how fast the door swings from open to about 6–10 inches or about 15 degrees from the closed position. Remember, because the spring has been compressed, its power is very high at the open position. Standard door closer power decreases dramatically as the spring expands. If the spring power is released too quickly, the door might slam shut or there might not be enough force remaining to latch and secure the door.
The final stage is the latching speed, which controls the final inches or degrees of the closing arc. The force closing the door is controlled by the closer spring. The optimum installation is when there’s just enough spring force left in the closer after the door is latched. If there’s too much spring force left when the door is latched, this force is wasted, and there is probably too much spring force being made available. Too little spring force will result in either the door not latching or the door not latching occasionally. For these reasons, the most critical adjustment is the latching speed valve.
