Abstract: A golf ball playing surface assembly includes a plurality of different mats having different surfaces for simulating different golf playing surface conditions. A playing surface in a golf simulator, hitting bay or practice area is provided with a rectangular recess of predetermined depth, length and width. The mats have different piles for simulating different playing surface conditions, and can be placed side by side in any selected configuration in the recess to cover at least a major portion of the recess area. The depth of the recess is substantially equal to the height of at least some of the mats, so that a hitting surface is provided which is substantially flush with the surrounding floor area. Different combinations of mats can be placed in the recess to simulate different playing conditions.

Abstract: A golf simulator has a housing and three arrays of IR receivers and emitters positioned in the housing. A launch area is established near one end of the housing, and a user can launch a golf ball located in the launch area and drive the ball into the housing through the planes defined by the arrays of emitters and against a screen positioned at one end of the housing. The planes established by the arrays are disposed vertically and perpendicular to the angle of travel of the ball. A computer is connected to the IR receivers, which detect the passage of the golf ball through each respective plane. Based upon the signals from the receivers the computer, using triangulation techniques, determines the horizontal and vertical position, as well as the velocity, of the ball for a range of shots including drives, steep chip shots and putts less than 4 feet.

Abstract: A golf ball playing surface assembly includinga playing surface having a rectangular recess of predetermined depth, length and width;a plurality of different mats for selectively placing in the recess to simulate different playing conditions, each mat having at least one dimension less than a corresponding dimension of the recess, and whereby at least two mats placed side by side will substantially fill the recess with no gaps; andthe mats including at least one mat having at least two different surface areas for simulating different golf playing surface conditions.

Abstract: A sports simulator has a housing and two arrays of IR receivers and emitters positioned in the housing. A launch area is established near one end of the housing, and a user can launch an object such as a golf ball located in the launch area and drive the ball into the housing through the planes defined by the arrays of emitters and against a screen positioned at one end of the housing. A computer is connected to the IR receivers, which detect the passage of the object through the respective plane. Based upon the signals from the receivers the computer, using triangulation techniques, determines the horizontal and vertical position, as well as the velocity, of the object. The computer can also determine the spin of the golf ball, and cause an image of the golf ball, as it would have appeared travelling away from the golfer had it not encountered the screen, to be displayed on the screen.

Abstract: A collapsible multiple shelf file is constructed of a sheet of cardboard or the like, cut and scored to define a plurality of panels foldable into an open front box-like structure having double side walls with inner sidewalls having slots for receiving a plurality of shelf panels. The side panels are double with inner panels that overlap and extend to the inside of the outer panels and further overlap flaps which extend downward from the top panel and similar flaps which extend upward from the bottom panel. The outer side panels are formed with rectangular cuts for defining a loop for receiving and holding stacked material such as envelopes. The top panel includes cut circles which can be punched out for receiving tubular members for holding pencils and the like. The shelf sheets or panels are provided with a stop member which may be folded upward to stop short forms or sheets of paper.