04070940 is referenced by 90 patents and cites 4 patents.

A shear machine having a blade for cutting successive increments of material from flat sheet work stock has a cutting zone guarded by a curtain of light. Photosensitive means actuates a brake to stop blade motion if an object extends through the light curtain towards the cutting zone. Hold-down mechanism is operated by a lever or the like situated outside of the guarded region to enable the final portion of a sheet of work stock to be manually held in place at the cutting zone without penetrating the light curtain. The plane of the light curtain inclines towards the front of the shear machine enabling the hold-down mechanism control lever or the like to be situated on the machine above the cutting zone where it may be reached without interception of the light curtain by the operator.

Title
Machine tool with protective light curtain and work stock holding mechanism
Application Number
5/764666
Publication Number
4070940
Application Date
February 1, 1977
Publication Date
January 31, 1978
Inventor
Robert W Thomas
Blue Mound
IL, US
Harry W Sinnard
Decatur
IL, US
John H McDaniel
Decatur
IL, US
Agent
Phillips Moore Weissenberger Lempio & Majestic
Assignee
Caterpillar Tractor Co
IL, US
IPC
B26D 7/24
B26D 7/02
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