1. A heat sealer, comprising:
a press mechanism;
a heater attached to a jaw of the press mechanism; and
an electric power circuit connected to the heater, the electric power circuit receiving electric power from an external power source;
wherein the heat sealer clamps and presses an object made of a thermoplastic resin by using the press mechanism, instantaneously heats the heater by passing a high electric current through the heater in a short time, melts the object, and cools and solidifies the object by interrupting the electric current;
wherein the heater includes:
(a) a thin thermal-electrical insulator plate that has an appropriate size and thickness and that is superposed on a heat dissipating base or on the jaw that also serves as the heat dissipating base, the heat dissipating base being made of a metal and disposed on the jaw of the press mechanism,
(b) one or more heater wires each of which is a thin metal resistor plate superposed on the thin thermal-electrical insulator plate, each heater wire including an electrode that is connected to the electric power circuit and a heat generating portion having a strip-like shape or a desired shape,
(c) a thermally conductive electrical insulator superposed on the heat generating portion, the thermally conductive electrical insulator having a flat surface that closely contacts the heat generating portion, the thermally conductive electrical insulator being an electrical insulator and having a thermal conductivity that is equal to or higher than that of alumina,
(d) a thermal-electrical insulator that covers exposed portions of the heater wires and the electrode, the thermal-electrical insulator surrounding a part of the exposed portions located around the thermally conductive electrical insulator so that the part is electrically and thermally insulated and surrounding a remaining part of the exposed portions so that the remaining part is at least electrically insulated, and
(e) a thin release film superposed constantly or as necessary on the thermally conductive electrical insulator with or without a gap therebetween; and
wherein the elements of the heater in (a) to (e) above are made to closely contact each other and fixed at necessary positions by using an adhesive, a sticky agent, or a physical method.
2. The heat sealer according to claim 1,
wherein the heat generating portion of each heater wire that is the thin metal plate resistor plate has slits that cross a longitudinal direction, so that the heater wire has a shape that is thin and long as a path of electricity and that suppresses extension and contraction in the longitudinal direction.
3. The heat sealer according to claim 1, further comprising:
a plate or ribbon heater reinforcing member disposed between the thermally conductive electrical insulator and the release film so as to be in close contact with the thermally conductive electrical insulator, the heater reinforcing member having a first surface and a second surface, the first surface being a flat surface that closely contacts an upper surface of the thermally conductive electrical insulator, the second surface being a flat surface or a three-dimensional surface that is suitable for sealing an object, the heater reinforcing member being made of a metal or a carbon composite having an appropriate strength,
wherein the heater reinforcing member is surrounded by a heat insulator or a thermal-electrical insulator as necessary and fixed.
4. The heat sealer according to claim 1,
wherein the thermally conductive electrical insulator is made of aluminium nitride, silicon carbide, or a ceramic including aluminium nitride and silicon carbide as main components.
5. The heat sealer according to claim 1, wherein said the thermally conductive electrical insulator is a ceramic plate.
6. The heat sealer according to claim 5, wherein said ceramic plate is made of a plurality of stacked plates.
7. A heater for use in a heat sealer that includes a press mechanism, the heater attached to a jaw of the press mechanism, and an electric power circuit connected to the heater, the electric power circuit receiving electric power from an external power source, in which the heat sealer clamps and presses an object made of a thermoplastic resin by using the press mechanism, instantaneously heats the heater by passing a high electric current through the heater in a short time, melts the object, and cools and solidifies the object by interrupting the electric current, the heater comprising:
(a) a thin thermal-electrical insulator plate that has an appropriate size and thickness and that is superposed on a heat dissipating base or on the jaw that also serves as the heat dissipating base, the heat dissipating base being made of a metal and disposed on the jaw of the press mechanism,
(b) one or more heater wires each of which is a thin metal resistor plate superposed on the thin thermal-electrical insulator plate, each heater wire including an electrode that is connected to the electric power circuit and a heat generating portion having a strip-like shape or a desired shape,
(c) thermally conductive electrical insulator superposed on the heat generating portion, the thermally conductive electrical insulator having a flat surface that closely contacts the heat generating portion, the thermally conductive electrical insulator being an electrical insulator and having a thermal conductivity that is equal to or higher than that of alumina,
(d) a thermal-electrical insulator that covers exposed portions of the heater wires and the electrode, the thermal-electrical insulator surrounding a part of the exposed portions located around the thermally conductive electrical insulator so that the part is electrically and thermally insulated and surrounding a remaining part of the exposed portions so that the remaining part is at least electrically insulated, and
(e) a thin release film superposed constantly or as necessary on the thermally conductive electrical insulator with or without a gap therebetween; and
wherein the elements of the heater in (a) to (e) above are made to closely contact each other and fixed at necessary positions by using an adhesive, a sticky agent, or a physical method.
8. The heater according to claim 7,
wherein the heat generating portion of each heater wire that is the thin metal plate resistor plate has slits that cross a longitudinal direction, so that the heater wire has a shape that is thin and long as a path of electricity and that suppresses extension and contraction in the longitudinal direction.
9. The heater according to claim 7, further comprising:
a plate or ribbon heater reinforcing member disposed between the thermally conductive electrical insulator and the release film so as to be in close contact with the thermally conductive electrical insulator, the heater reinforcing member having a first surface and a second surface, the first surface being a flat surface that closely contacts an upper surface of the thermally conductive electrical insulator, the second surface being a flat surface or a three-dimensional surface that is suitable for sealing an object, the heater reinforcing member being made of a metal or a carbon composite having an appropriate strength,
wherein the heater reinforcing member is surrounded by a heat insulator or a thermal-electrical insulator as necessary and fixed.
10. The heater according to claim 7,
wherein the thermally conductive electrical insulator is made of aluminium nitride, silicon carbide, or a ceramic including aluminium nitride and silicon carbide as main components.
11. The heat sealer according to claim 7, wherein said the thermally conductive electrical insulator is a ceramic plate.
12. The heat sealer according to claim 11, wherein said ceramic plate is made of a plurality of stacked plates.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A lawn mower comprising:
a first bearing frame;
a grass cutting unit, said unit being mounted beneath said first bearing frame;
means for taking the grass clippings;
a catcher for receiving and collecting the grass clippings;
a rear wall having an upper side wall hinged to the catcher through a pair of levers radially secured to and cantilevering from a tube rotatable within a pair of supports provided on an upper wall of the catcher;
said means for taking the grass clippings comprising a duct for conveying the grass clippings from said grass cutting unit to said catcher;
a second frame, arranged between said catcher and said first bearing frame, said second frame being hinged to the first bearing frame so as to enable said catcher to assume a working configuration at which said catcher is lowered relative to the first bearing frame and an emptying configuration at which said catcher is raised with respect to said first bearing frame;
wherein, at said working configuration said catcher and said cutting unit are vertically aligned, so that the overall bulk of the mower is substantially the same as that of said catcher or said cutting unit.
2. A lawn mower according to claim 1, wherein said second frame is hinged to said first bearing frame in a manner such that said second frame remains generally parallel to said first bearing frame while the catcher is being raised and lowered.
3. A lawn mower according to claim 2, wherein said catcher comprises plastic material.
4. A lawn mower according to claim 1, wherein said tube further comprises a pair of actuating levers arranged at the ends of said tube to rotate the tube and hence the levers for opening and closing the rear wall.
5. A lawn mower according to claim 1, wherein said catcher is hinged at its lower part to said second frame.
6. A lawn mower according to claim 5, wherein lifting means are provided between said second frame and said catcher, said lifting means arranged to tilt the catcher when it is to be emptied.
7. A lawn mower according to claim 6, wherein said lifting means includes a hydraulic cylinder.
8. A lawn mower according to claim 1, wherein said first bearing frame comprises a plurality of metal crosspieces or section bars welded or bolted together.
9. A lawn mower according to claim 8, wherein said first bearing frame comprises a pair of hexagonal side walls arranged on the mower sides and defining corresponding upper, lower and oblique crosspieces of the first bearing frame.
10. A lawn mower according to claim 9, wherein said first bearing frame is supported by four uprights, each carried by a corresponding caster arranged to support the first frame bearing at an appropriate distance from ground and to allow the mower to be drawn during operation.
11. A lawn mower according to claim 9, wherein the pair of lower crosspieces bears the cutting unit.
12. A lawn mower according to claim 1, wherein said cutting unit comprises a plurality of rotary knives housed within a deck or housing.
13. A lawn mower according to claim 1, wherein said grass taking means comprises a suction turbine to suck grass clippings and to send them through said duct.
14. A lawn mower according to claim 13, wherein said duct comprises a flexible duct that is fitted at its lower end to a flange located at an outlet port of the turbine, and at its upper end to a second flange horizontally cantilevered on the side of the first bearing frame through a bracket.
15. A lawn mower according to claim 14, wherein an elbow is provided above the second flange and downstream of the second flange along the path of the grass clippings, the elbow laterally terminating in the catcher through an opening provided in a side wall of the catcher.
16. A lawn mower according to claim 15, wherein said elbow is removably fitted onto the second flange so as to be disconnectable from the flange when the catcher is tilted to be emptied.
17. A lawn mower according to claim 1, wherein said second frame supporting the catcher is hinged onto the first bearing frame through a pair of arms arranged on each side of both frames, said arms being pivotally connected to the second frame and to the upper crosspiece of the first bearing frame.
18. A lawn mower according to claim 17, wherein said pair of arms include first, outer arms extending from a pivot pin provided on the front end of the second frame to a pivot pin located substantially at the middle of the upper crosspiece of the first bearing frame, and second, inner arms extending from a pivot pin provided on the second frame to a pivot pin located at the rear end of the upper crosspiece of the first bearing frame.
19. A lawn mower according to claim 18, wherein said inner arms are joined, in correspondence of the pins, by a transversely arranged crosspiece having welded thereto two cantilevered levers.
20. A lawn mower according to claim 19, wherein corresponding hydraulic cylinders are provided between said levers and said first bearing frame, and said levers are rotatable such that said crosspiece joining the inner arms may be rotated to lift said second frame while keeping the second frame generally parallel to the first bearing frame.
21. A lawn mower according to claim 20, wherein a connection rod is provided between the outer arms and the inner arms for each arm pair and is pivotally connected to a pair of plates, each plate secured to one of said arms.
22. A lawn mower according to claim 6, wherein means for opening said rear wall are controlled by a hydraulic system carried by said mower.
23. A lawn mower according to claim 1, wherein a standard three-point linkage and a transmission shaft connected to a power takeoff are provided for connection to any tractor or self-propelled vehicle.