Table saws are widely used in tool shops and on job sites for powered cutting or trimming of construction items in a wide range of applications. Power saw cutting can include close or precise trimming of small amounts of excess material from a workpiece. An ever-present concern is safety in using the saw blade, which is very sharp and moving at a high rate of speed. Severe injuries such as severed fingers or deep lacerations can occur accidentally to the hand of a user handling a workpiece on a table saw almost instantaneously.
Various safety systems in particular for circular saws have been developed to reduce the dangers of working with an exposed blade rotating at high speed. Blade guards have been designed to enclose the area proximate a saw blade while allowing a workpiece to pass under it in order to prevent injuries to the user. An example of a blade guard assembly for a table circular saw is described in U.S. Pat. No. 4,625,604 to Handler et al., issued Dec. 2, 1986. However, such blade guards may prevent a user from precisely manipulating a workpiece close to the cutting edge of the blade and therefore detract from the user's accuracy in cutting or trimming a workpiece.
Some table saw systems also provide a guide or fence on the table top for aligning a workpiece for precise movement through the position of the saw blade in conjunction with using a conventional blade guard to prevent injuries. An example of a table saw with a combination of guide fence and blade guard is commercially available from Axminster Tool Centre, United Kingdom, under the product name Axminster Hobby Series BTS10ST table saw, which offers a rip fence on support rails with a flip-over function so that it can act either as a fence or wide board support rail. However, while the rip fence can maintain the edge of the workpiece to be cut or trimmed in spaced relation to the position of the saw blade, it does not allow the user to precisely manipulate the workpiece itself close to the position of the saw blade, particularly for a workpiece that may have a complex contour or three-dimensional shape.
Other table saw safety systems have been developed which are intended to drop the blade below the surface of the table saw if the user releases a brake latch, such as by releasing a foot from a safety pedal. An example of a power saw safety latch is described in U.S. Pat. No. 8,245,612 to Chung et al., issued Aug. 21, 2012. However, even a slight delay in releasing the latch can result in serious injury.
It would therefore be advantageous to provide a table saw safety system that allows a user to manipulate a workpiece close to the position of a saw blade while protecting the user's hand from risk of accidental contact with the saw blade.