Material misfeed detector for power press

Claim 2

A material misfeed detector for a power press, wherein the material is progressively transferred through a work station in said power press, comprising a base located at said work station and over which said work material is progressively transferred, a work tool located above said base and vertically movable relative thereto to perform the preselected work operation on said work material, operating means for producing the vertical movement of said work tool, and a safety device for detecting a misfeed of said work material and being operable to discontinue operation of said operating means so as to prevent damage to said work tool in striking the misfed work material, said safety device including a fluid discharge member located on one side of said work material at said work station and normally discharging a stream of compressed air therefrom through a preformed opening in said work material, a pressure responsive device responsive to a variation in pressure of the compressed air discharged from said fluid discharge member and when a misfeed of said work material occurs at said work station for discontinuing operation of said operating means, a contact located in circuit with said operating means and in parallel relation with said pressure responsive device, means for completing a circuit to said contact upon normal downward movement of the work tool during a work operation, said contact providing for feeding operation of said work material during upward movement of said work tool after a work operation.

Claim 3

A material misfeed detector as set forth in claim 1, a receiver located on the other side of said work material at said work station and in vertical alignment with said fluid discharge member, said receiver communicating directly with said fluid discharge member upon normal feed of said work material to said work station through the preformed opening in said work material for receiving the jet of compressed air therefrom, the pressure responsive device communicating with said receiver and being actuated in response to a predetermined pressure exerted thereon by the compressed air directed to said receiver for effecting operation of said operating means.

Claim 4

Apparatus as set forth in claim 2, said nozzle being located above said work material in a holder for said work tool and vertically movable therewith, said receiver being located in said base in vertical alignment with said nozzle.

Claim 5

Apparatus as set forth in claim 3, said base having a bore formed therein for receiving said receiver in sliding and floating relation, a chamber formed in said base and communicating with said bore, said receiver extending through said bore into the chamber located interiorly of said base and havinG a passage formed therein that communicates with said chamber and that is aligned with said nozzle for receiving the compressed air ejected therefrom, wherein the compressed air as directed into said passage is received in said chamber and retains said receiver in sliding and floating relation in said bore, and a conduit communicating with said chamber and directing the compressed air received from said passage to said pressure responsive device.

Claim 6

Apparatus as set forth in claim 4, said passage as formed in said receiver including an upper reduced portion that communicates with said nozzle, a lower enlarged portion that communicates with the chamber in said base, the reduced portion of the passage being confined within the bore in said base and the enlarged portion extending inwardly for a substantial portion of the interior chamber in said base.

Claim 7

Apparatus for automatically performing a preselected work operation on a work material that is progressively transferred through a work station in said apparatus, a base located at said work station and over which said work material is progressively transferred, a work tool located above said base and vertically movable relative thereto to perform the preselected work operation on said work material, and operating means for producing the vertical movement of said work tool, the improvement comprising a safety device for detecting a misfeed of said work material to said work station and being operable to discontinue operation of said operating means so as to prevent damage to said work tool in striking the misfed work material, said safety device including a nozzle located on one side of said work material at said work station and discharging a jet of compressed air therefrom, a receiver located on the other side of said work material at said work station and in vertical alignment with said nozzle, said receiver communicating directly with said nozzle upon normal feed of said work material to said work station through a preformed opening in said work material for receiving the jet of compressed air therein, a pressure responsive device communicating with said receiver and being actuated in response to a predetermined pressure exerted thereon by the compressed air directed to said receiver for effecting operation of said operating means, said pressure responsive device being responsive to a decrease in pressure when the jet of compressed air from said nozzle is deflected in its path through said work material to the receiver due to misfeed of said work material to interrupt the operation of said operating means, said nozzle being located above said work material in a holder for said work tool and vertically movable therewith, said receiver being located in said base in vertical alignment with said nozzle, a contact located in circuit with said operating means and in parallel relation with said pressure responsive device, and means for completing a circuit to said contact upon normal downward movement of the holder for said work tool during a work operation, said contact providing for feeding operation of said work material during upward movement of said work tool after a work operation.

Claim 8

Apparatus for automatically performing a preselected work operation on a work material that is progressively transferred through a work station in said apparatus, a base located at said work station and over which said work material is progressively transferred, a work tool located above said base and vertically movable relative thereto to perform the preselected work operation on said work material, and operating means for producing the vertical movement of said work tool, the improvement comprising a safety device for detecting a misfeed of said work material to said work station and being operable to discontinue operation of said operating means so as to prevent damage to said work tool in striking the misfed work material, said safety device including a nozzle located on one side of said work material at said work station and discharging a jet of compressed air therefrom, a receiver located on the other side of said work material at said work station and in vertical alignment with said nozzle, said receiver communicating directly with said nozzle upon normal feed of said work material to said work station through a preformed opening in said work material for receiving the jet of compressed air therein, a pressure responsive device communicating with said receiver and being actuated in response to a predetermined pressure exerted thereon by the compressed air directed to said receiver for effecting operation of said operating means, said pressure responsive device being responsive to a decrease in pressure when the jet of compressed air from said nozzle is deflected in its path through said work material to the receiver due to misfeed of said work material to interrupt the operation of said operating means, said nozzle being located above said work material in a holder for said work tool and vertically movable therewith, said receiver being located in said base in vertical alignment with said nozzle, a contact located in circuit with said operating means and in parallel relation with said pressure responsive device, and means for completing a circuit to said contact upon normal downward movement of the holder for said work tool during a work operation, said contact providing for feeding operation of said work material during upward movement of said work tool after a work operation.

Claim 9

Apparatus as set forth in claim 6, said contact being defined by an elongated probe that is adjustable in position relative to an electrical ground.

Claim 10

Apparatus as set forth in claim 3, said pressure responsive device being located in a relay circuit that is electrically interconnected to a circuit for an emergency brake, wherein said emergency brake is energized to discontinue operation of said operating means when said pressure responsive device is not moved sufficiently due to a decrease in pressure to said receiver.

Claim 11

A material misfeed detector as set forth in claim 1, said contact being defined by an elongated probe that is adjustable in position relative to an electrical ground.