Opposed C-shaped cuts can be made in plastic film in a continuous manner by passing the film between a punch roll bearing specially designed punches and a mating roll having wells for receiving the punches. The special design of the punches overcomes the problem of stretching and tearing of the film normally encountered in attempting to make such cuts in plastic film using a rotary punch.
A cutting tool has cutting teeth attached to a base surface of the cutting tool. Each tooth is provided with a generally vertical leading face that is arranged at an angle relative to a forward stroke direction of the cutting tool, and a corresponding, similarly shaped trailing face relative to said forward stroke direction. Extending between the leading face and the trailing face is at least one cutting surface perpendicular to the leading face. The cutting surface has an elongated, generally linear crest having a length that extends between the leading and trailing faces and is situated at a distance from the base surface. Each leading face forms a piercing corner with the crest. The teeth of the cutting tool are arranged in a plurality of rows, with each row being oriented generally perpendicularly to the forward stroke direction. Each leading face of each tooth of at least one row is oriented at an angle relative to the forward stroke direction.
In the operation of hole punching apparatus, a method of changing punched hole formats in paper, for loose leaf binder pages or the like, using cooperating rollers for the male punches and female die members having the various formats embodied therein, so that after the male punches are projected into the female die members for any one selected format for achieving alignment or registration therebetween, this alignment for any other subsequent format does not have to be repeated and only the punches placed in mounting openings on the male punch roller for the subsequent format; the female die members being no problem because they do not, without a cooperating male punch, cause punched holes in the paper.
The invention pertains to the method for forming air flow control orifices in a patient body temperature regulating blanket consisting of an inflated envelope defined by thin plastic film wherein temperature controlled air flows through the blanket orifices upon the patient's body. The blanket side disposed toward the patient is pierced by a sharp pointed punch having a plurality of intersecting facets defining sharpened intersecting edges. The punch apex and facet intersecting edges are related to the moving film in such a manner that the penetration of the punch forms a plurality of flexible valve flaps, and the valve flaps engaging the patient's body will be retained in a closed condition to restrain air flow through those orifices engaging the body to prevent exposure to excessive air temperatures.
The invention pertains to the method and apparatus for forming air flow control orifices in a patient body temperature regulating blanket consisting of an inflated envelope defined by thin plastic film wherein temperature controlled air flows through the blanket orifices upon the patient's body. The blanket side disposed toward the patient is pierced by a sharp pointed punch having a plurality of intersecting facets defining sharpened intersecting edges. The punch apex and facet intersecting edges are related to the moving film in such a manner that the penetration of the punch forms a plurality of flexible valve flaps, and the valve flaps engaging the patient's body will be retained in a closed condition to restrain air flow through those orifices engaging the body to prevent exposure to excessive air temperatures.
A cushioning conversion machine, converting method and dunnage product characterized by a novel connecting assembly which provides a unique interlock between overlapped portions of sheet-like stock material forming a dunnage product to prevent "unzippering" of the product. The connecting assembly includes a pair of loosely meshed stitching wheels, a first one of the stitching wheels having a plurality of radial projections protruding from a radially outer circumferential surface thereof, and a second one of the stitching wheels including a plurality of recesses for receiving the radial projections in meshed relationship upon rotation of the stitching wheels. The radial projections each have a radially outer end portion forming a hook, whereby, upon rotation of the stitching wheels with the overlapped portions of the stock material passing therebetween, the radial projection will pierce through and form a perforation in the overlapped portions as it moves into the recess in the second stitching wheel and then hook and reversely pull back through the perforation at least partway a tab portion of the overlapped portions adjacent the perforation.