Punch press with safety door

Claim 2

A punch press having a support, a vertically reciprocable ram on said support and normally operable to shift a punch downwardly and upwardly through a working stroke between retracted and advanced positions, said ram being selectively operable to shift the punch upwardly beyond said retracted position to a tool change position, a tubular housing mounted on said support and surrounding said punch, a stripper plate supported on the lower end of said housing and formed with a hole within which said punch reciprocates during said working stroke, said housing comprising a fixed section and a door section hinged on said fixed section to swing outwardly and inwardly relative to the latter about an upright axis between closed and open positions, a strike mounted on said door section, and a latch movable with said ram and engageable with said strike during said working stroke to hold said door section in said closed position but automatically releasable from the strike to permit outward swinging of said door section to said open position when said ram shifts said punch upwardly to said tool change position.

Claim 3

A punch press as defined in claim 1 in which said latch comprises a downwardly projecting finger movable with said ram, said strike comprising a member secured to the inner side of said door section and formed with an upwardly opening hole for slidably receiving said finger.

Claim 4

A punch press as defined in claim 1 further including means operable independently of said latch for holding said door section in said closed position and selectively releasable to permit swinging of said door section to said open position when said punch is in said tool change position.

Claim 5

A punch press as defined in claim 3 in which said means comprise a detent mounted on one of said sections and movable into latching engagement with the other section automatically as an incident to swinging of said door section to said closed position.

Claim 6

A punch press as defined in claim 4 in which said detent comprises a plunger mounted for endwise movement in said one section, a spring biasing said plunger toward the other section, and a hole in said other section for receiving said plunger when said door section is in said closed position and shaped to automatically release said plunger as said door section is swung toward said open position.

Claim 7

A punch press as defined in claim 1 further including means responsive to the position of said door section and operable to produce a signal when the door section is out of said closed position, and means responsive to said signal for preventing movement of said ram through said working stroke.

Claim 8

A punch press as defined in claim 6 furtHer including a passageway in one of said sections and having an open end which is blocked by the other of said sections when said door section is in said closed position and which is unblocked when said door section is in said open position, means for introducing pressurized air into said passageway and operable to pressurize the latter to a preselected pressure level when said door section is in said closed position, and said signal producing means being operable to produce an electrical signal in response to the pressure in the passageway dropping below said level when said door section is moved to said open position and the end of the passageway is unblocked.

Claim 9

A punch press comprising a support, a reciprocable ram on said support and normally operable to shift a punch through a working stroke between and retracted and advanced positions, said ram being selectively operable to retract the punch beyond said retracted position to a tool change position, a tubular housing mounted on said support and surrounding said punch, said housing comprising a fixed section and a door section movable between open and closed positions relative to said fixed section, and means for preventing movement of said door section from said closed position at all times during said working stroke and operable to permit movement of said door section to said open position when said ram retracts said punch to said tool change position.

Claim 10

A punch press comprising a support, a reciprocable ram on said support and normally operable to shift a punch through a working stroke between and retracted and advanced positions, said ram being selectively operable to retract the punch beyond said retracted position to a tool change position, a tubular housing mounted on said support and surrounding said punch, said housing comprising a fixed section and a door section movable between open and closed positions relative to said fixed section, and means for preventing movement of said door section from said closed position at all times during said working stroke and operable to permit movement of said door section to said open position when said ram retracts said punch to said tool change position.

Claim 11

A punch press as defined in claim 8 in which said means comprises a latch reciprocable with said ram, and a strike on the inner side of said door section and telescoping with said latch during said working stroke.

Claim 12

A punch press comprising a support, a reciprocable ram on said support and normally operable in an automatic cycle to shift a punch through a working stroke between retracted and advanced positions, a tubular housing mounted on said support and surrounding said punch, said housing comprising a fixed section and a door section movable between open and closed positions relative to said fixed section, means for releasably holding said door section in said closed position, a passageway in one of said sections and having an open end which is blocked by the other of said sections when said door section is in said closed position and which is unblocked when said door section is in said open position, means for introducing pressurized air into said passageway and operable to pressurize the latter to a preselected pressure level when said door section is in said closed position, signal producing means operable to produce an electrical signal in response to the pressure in the passageway dropping below said level when said door section is moved to said open position and the end of the passageway is unblocked, and means responsive to said signal for preventing automatic cycling of said ram through said working stroke.

Claim 13

A punch press comprising a support, a reciprocable ram on said support and normally operable in an automatic cycle to shift a punch through a working stroke between retracted and advanced positions, a tubular housing mounted on said support and surrounding said punch, said housing comprising a fixed section and a door section movable between open and closed positions relative to said fixed section, means for releasably holding said door section in said closed position, a passageway in one of said sections and having an open end which is blocked by the other of said sections when said door section is in said closed position and which is unblocked when said door section is in said open position, means for introducing pressurized air into said passageway and operable to pressurize the latter to a preselected pressure level when said door section is in said closed position, signal producing means operable to produce an electrical signal in response to the pressure in the passageway dropping below said level when said door section is moved to said open position and the end of the passageway is unblocked, and means responsive to said signal for preventing automatic cycling of said ram through said working stroke.