Search results
Results from the WOW.Com Content Network
Roll shutters on windows. Security roller shutters in a dead mall. A roller shutter, security shutter, coiling door, roller door or sectional overhead door is a specialized type of door or window shutter consisting of multiple horizontal slats, bars, or web systems interconnected through hinges. The mechanism involves lifting the door to open ...
The music data is stored by means of perforations. The mechanism of the instrument reads these as the roll unwinds, using a pneumatic, mechanical or electrical sensing device called a tracker bar, and the mechanism subsequently plays the instrument. After a roll is played, it is necessary for it to be rewound before it can be played again.
This is an accepted version of this page This is the latest accepted revision, reviewed on 16 February 2025. Device to open or close door Various examples of door handles throughout history A door handle or doorknob is a handle used to open or close a door. Door handles can be found on all types of doors including: exterior doors of residential and commercial buildings, internal doors ...
Musical symbols are marks and symbols in musical notation that indicate various aspects of how a piece of music is to be performed. There are symbols to communicate information about many musical elements, including pitch, duration, dynamics, or articulation of musical notes; tempo, metre, form (e.g., whether sections are repeated), and details about specific playing techniques (e.g., which ...
A player piano roll being played Mastertouch Australian Dance Gems piano roll with lyrics printed to side. A piano roll is a music storage medium used to operate a player piano, piano player or reproducing piano. Piano rolls, like other music rolls, are continuous rolls of paper with holes punched into them. These perforations represent note ...
A crash bar (also known as a panic exit device, panic bar, or bump bar) [1] [2] is a type of door opening mechanism which allows users to open a door by pushing a bar. While originally conceived as a way to prevent crowd crushing in an emergency, crash bars are now used as the primary door opening mechanism in many commercial buildings.
The spool fits into the player piano spool box whereupon the free end of the music sheet is hooked onto the take-up spool which will unwind the roll at an even pace across the reading mechanism (the "tracker bar") The music score to be played is programmed onto the paper by means of perforations. Different player systems have different ...
A unique "roll-up" system generally defines a high-speed door from a conventional roller door. The door's main objective is to produce a high opening speed and the guiding system must allow smooth operations with minimal friction. Effortless movement will ensure the longevity of the door's moving parts and operating soundness.