Compression testing machine

Claim 2

A compression testing machine for testing cushioning material comprising: a foot plate with support means and driving means for mechanically placing the foot plate in an unloaded position where the weight of the foot plate is detached from the machine and is completely supported by the material, means for sensing the thickness of the material from the surface on which it rests to the bottom of the unloaded foot plate, means for transmitting a signal to modify an electric property indicating the thickness, means for utilizing the electric property to compel the foot plate to compress the material by a predetermined proportion of the sensed thickness, and means for indicating the compressive force of the material against the foot plate.

Claim 3

A machine as in claim 1, in which the foot plate is moved by a reversible electric drive motor and the means for sensing the thickness is a potentiometer coupled to the motor.

Claim 4

A machine as in claim 2, in which the electric property indicative of thickness is the resistance of one branch of a second potentiometer induced to track the potentiometer coupled to the foot plate drive motor.

Claim 5

A machine as in claim 3, in which the extent of movement of the foot plate to compress the material is determined by a fixed resistance added to that of the second potentiometer.

Claim 6

A machine as in claim 1, including means for automatically halting a conveyor carrying material to be tested with the material under the foot plate and means for automatically lifting the foot plate and rEstarting the conveyor after the compressive force is indicated.

Claim 7

A machine as in claim 5, including means for automatically halting said conveyor a second time for determination of compressive force in a second location.

Claim 8

A machine as in claim 1, in which the foot plate is loosely supported and capable of being lifted a small distance from its support when placed in contact with the material, and in which an electric switch is located for transmission of an electric signal to indicate thickness of the material on completion of the small distance of lift of the foot plate from its support.

Claim 9

A machine as in claim 7, in which the means for placing the foot plate in contact with the material is connected for lowering the foot plate support at a fast speed until the foot plate is lifted from its support, and is connected to drive at a much slower speed thereafter until completion of lift of the foot plate from its support.

Claim 10

A machine as in claim 8, in which the means for placing the foot plate in contact with the material is connected to drive at an intermediate speed during compression of the material by the foot plate.

Claim 11

A machine as in claim 4, in which the foot plate is loosely supported and capable of being lifted a small distance from its support when placed in contact with the material, an electric switch is located for transmission of an electric signal terminating adjustment of the second potentiometer on completion of the small distance of lift of the foot plate from its support, the foot plate drive is connected for lowering the foot plate at a fast speed until the foot plate is lifted from its support, at a much slower speed thereafter until completion of lift of the foot plate from its support, and at an intermediate speed during compression of the material by the foot plate, and the machine includes means for automatically halting a conveyor when material carried by the conveyor is under the foot plate and means for automatically raising the foot plate and restarting the conveyor after the compressive force is indicated.