| 摘要 |
A double support wall roof curb linear form fabricated from a continuous strip of metal of substantially uniform thickness into an elongated structure having both inner and outer support walls. The linear form has a top member extending the length of the form, an inner portion bent from one edge of the top member and an outer portion bent from the other edge of the top member. Both the inner and outer portions function as supports for equipment mounted upon a finished roof curb incorporating the linear form. The roof curb linear form is fabricated by first forming the inner and outer portions before formation of the top member is begun. Thereafter, the top member is formed by applying pressure to the strip of metal on opposite sides of the strip at the location of the top member. If the bottom of the linear form is to be open, pressure may be applied by a ram having an offset portion to accommodate the formed bottom member of the linear form as the form is fabricated. If the bottom of the linear form is to be closed, a cantilever back-up can be used in combination with a ram, with the cantilever back-up ultimately being located wholly within the fabricated roof curb linear form.
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