Door closers, also known as door levers, are one of the most popular tools used in the industry. They provide added safety and security to your home while you are away on business. However, a few people may not know that these types of doors were in use in the industry long before these systems were invented. One of the first types of door levers was the aluminium door frames . This type of door lever uses a handle at one end that will allow the door to be opened or closed. In most cases, the door can also be opened from the inside when the lever is pulled. These kinds of door levers were originally designed to be used on top of a control panel. It was a quick and easy way to control who could not use the door. The system would automatically allow access only to those who had a key. In big office buildings, the control panel was commonly located in the control room in the building. In smaller offices, the control panels were often installed in the entranceway. This t...