Abstract: A machine wherein flat blanks are fed from a stack thereof to be folded and glued into envelopes. The machine is provided with an optical sensing device which is operable to sense when the stack of blanks diminishes to a predetermined height whereupon the machine will be turned off automatically so as to prevent a plurality of blanks from being simultaneously fed into the machine from the diminished stack to jam the machine. The machine operator can then add blanks to the stack and restart the machine. The sensing device can be turned off by the operator in order to run all of the blanks in the stack through the machine at the end of a blank run or at the end of a working day.

Abstract: A friction brake and safety slip clutch is positioned between a gumbox and a hand operated pinion shaft used to raise and lower the gumbox into contact with sealant transfer rollers of an apparatus for applying sealant material to envelopes. The brake and clutch prevents the gumbox from falling from a raised elevation during rotation of the pinion shaft or after the elevation has been attained.

Abstract: An RF dielectric heater has a variable power output and stable output frequency. A power controller provides variable phase angle control of three-phase AC power. A delta-wye power transformer is coupled between the power controller and a rectifier circuit. The rectifier circuit converts the stepped up, high voltage AC power from the transformer into a DC power output. An RF oscillator circuit driven by the DC power output is coupled to a tank circuit. A load, comprising RF electrodes, create an RF field to heat material passed through the field. The RF electrodes are coupled to the tank circuit in a manner characterized by the absence of any tuning components.

Abstract: A method and apparatus for R.F. drying of coated articles, such as gummed envelope flaps wherein the wet gummed flaps are moved through a curvilinear array of electrodes comprising a plate and a grid. The envelopes are carried between two belts around a drum having the plate and grid disposed adjacent to the periphery of the drum. The R.F. current travels diagonally between offset electrodes mounted on the plate and grid. The plate and grid are mounted in a housing which includes an air circulating system to remove heat and moisture from the housing. A screen forms a portion of one wall of the housing through which heat and moisture are exhausted from the housing. The drum is provided with fan blades to remove heat and moisture from within the confines of the drum.

Abstract: Envelope blanks are scored and folded by pressing the flat blanks through a series of scoring and folding rolls. The rolls include vacuum rolls which invert the envelope blanks during the scoring operation. The blanks are scored laterally and as they pass over the outer surface of one of the vacuum rolls they are scored longitudinally. During the longitudinal scoring operation, the envelopes are curvilinear due to their being drawn down onto one of the vacuum rolls. After the longitudinal scoring operation, the blanks are inverted by being folded along the transverse score. The inverted, folded blanks are then moved along by a pair of cooperating vacuum rolls to a gumming station. After being gummed, the blanks are folded along their longitudinal scores with the folded flaps being secured in place by the gum.

Abstract: A quick opening envelope which gives full access to its interior upon opening is disclosed. The envelope is formed from a blank constructed from a single sheet of flexible material having a plurality of fold lines defining a front panel, a back panel, two side flaps and a closure flap. The back panel is attached to marginal areas of the side flap by means of a releasable adhesive material and to a central tab portion of the closure flap by conventional adhesive material. The closure flap tab is defined by a V-shaped formation of die cut perforations, each of which includes a curved portion and a straight portion. The V-shaped formation of perforations enables neat and easy opening of the envelope by lifting to separate the tab from the closure panel and the back panel from the side panels.

Abstract: A quick opening envelope which gives full access to its interior upon opening is disclosed. The envelope is formed from a blank constructed from a single sheet of flexible material having a plurality of fold lines defining a front panel, a back panel, two side flaps and a closure flap. The back panel is provided with a V-shaped array of die cut perforations, each of which includes an arc portion and a tangent portion. The V-shaped array of perforations enables neat and easy opening of the envelope.

Abstract: Apparatus for applying gum to spaced portions of an envelope is provided with means for sensing the absence of an envelope on a conveyor belt feeding the envelopes to the gummer apparatus. In response to sensing the absence of an envelope on the conveyor belt, a gummer cylinder containing spaced gummer pads for applying gum to the flap and body of the envelope is precluded from rotating by disengagement of a clutch between the gummer cylinder and its drive and simultaneous contact of a brake with the cylinder.

Abstract: An apparatus for applying latex areas to the seal flaps of paper envelopes and drying the latex is adapted to be placed either "in-line" or "off-line" with respect to a die-cut high speed envelope manufacturing machine. The apparatus includes a rotatable electrically insulated drum which acts as the ground for a radio frequency dryer (dielectric dryer) whose positive electrodes are adjustably spaced from the drum surface. The envelopes, during application of the latex and its drying, are held between flexible belts having projecting guides and are conveyed, still between the belts, by the rotating drum beneath the electrodes, with the latex exposed to the radio frequency drying.

Abstract: Gum applying apparatus including a pair of gum applying dies mounted on a common shaft for applying gum along and adjacent to the side edges of an envelope blank during the manufacture of the blank into an envelope. Each of the dies includes a central circular plate and a pair of circular sectors spaced from each other about the circumference of the circular plate. The sectors are in contact with a gummer roll which transfers gum from a container to the sectors. The gum is applied by the sectors to spaced envelope blanks on a conveyor belt beneath the sectors. The space between the sectors is adjacent the conveyor when the space between the blanks on the conveyor traverses the gum applying station thereby precluding gum from being applied to the belt running through the station; but enabling the gum to be applied continually to the envelope blanks. Means are also disclosed to control the amount of gum transferred to the gum applying die sectors.

Abstract: Apparatus for feeding, scoring, gumming, and folding a blank into an envelope.

Abstract: An envelope is provided with a first and second button having a depending portion inserted through an opening in a flap and an adjacent body portion, respectively, which is then flattened by the application of ultrasonic energy to vibrate each button and its depending portion against an anvil, rendering each button captive on the envelope. A string is inserted through a slot or hole in the depending portion of one of the buttons and fused to the button as the depending portion is flattened. The string is used to releasably connect the buttons and thus, the envelope flap to the adjacent body portion.

Abstract: An envelope having a first tab adhered to the flap and a second tab adhered to the main body portion with means for releasably interconnecting the tabs. In one embodiment the second tab includes three elongated fingers, each integral with the tab and cut therefrom on three sides. An elongated member extends from the first tab and is releasably received under each finger. In another embodiment, the second tab includes one elongated finger integral with the tab and cut therefrom on two sides, and the first and second tabs have the same configuration which allows them to be cut from a piece of material without significant waste.

Abstract: An envelope having a first tab adhered to the flap and a second tab adhered to the main body portion with means for releasably interconnecting the tabs. In one embodiment the second tab includes three elongated fingers, each integral with the tab and cut therefrom on three sides. An elongated member extends from the first tab and is releasably received under each finger. In another embodiment, the second tab includes one elongated finger integral with the tab and cut therefrom on two sides, and the first and second tabs have the same configuration which allows them to be cut from a piece of material without significant waste.

Abstract: Apparatus for cleaning an adhesive applicator roll includes a plurality of air jets for directing an air stream against the roll to clean the same. A driven roller assembly rotates the roll as it is being cleaned by the jets.

Abstract: Envelopes having moistenable gum on the seal flap and back gum adhering the sides and bottom are manufactured by a process comprising applying a back gum to either the bottom flap or the side flaps in the form of microcapsules. When the bottom and side flaps are folded and pressure is applied, the microcapsules rupture causing the back gum to adhere the bottom and side flaps. Gum in the form of microcapsules can also be applied to the seal flap allowing the end user to seal without moisture.