1. An extruder for welding plastic components, having a front part for plasticizing and ejecting additional plastic welding material, and a rear part for feeding in a feeding direction and breaking up a continuous filament made of said additional plastic material; said rear part comprising: at least one feed channel and a worm screw arranged therein, said at least one feed channel being delimited by a thread of said worm screw on a first side thereof and by a sliding surface for said filament on a second opposite side thereof, and wherein a distance between said sliding surface and a crest of said thread decreases in the feeding direction along which said filament is fed, in order to provide scoring of increasing depth on said filament, said thread comprising at least one discontinuity of the worm thread that has a sharp discontinuity end for cropping said filament at said scoring.
2. The extruder of claim 1, wherein said thread comprises two separate thread starts, which are mutually parallel, said separate thread starts having at least two said worm thread discontinuities formed on an extension of said thread along a common continuous line that is transverse with respect to said thread.
3. The extruder of claim 2, wherein the last one of said discontinuities is formed on a portion of said thread that lies away from said sliding surface and intersects, or is at least tangent to, an imaginary continuation surface of said sliding surface.
4. The extruder of claim 3, wherein said thread is substantially cylindrical, while said sliding surface is inclined so as to converge toward said thread in the feeding direction of said filament.
5. The extruder of claim 1, comprising a shoulder for guiding said filament that is provided on said sliding surface and contrasts lateral thrust due to rotation of said worm screw.
6. The extruder of claim. 1, wherein said thread has roots with a square cross-section, said crests having a sawtooth cross-section, and a depth of said roots of said thread being greater than a diameter of said filament.
7. The extruder of claim 1, wherein said rear part comprises: a casing with a motor drive and a sleeve connected to said casing for actuating in rotation said worm screw; a rotation shaft accommodated in said sleeve and protruding from said motor drive and being rigidly fixed to said worm screw; an axial bearing of a conical roller type arranged at a bottom region of said cylindrical sleeve, said rotation shaft that protrudes from said motor drive being keyed on said bearing; a tubular bush being arranged adjacent to internal walls of said cylindrical sleeve and forming a rotation chamber for said worm screw; a longitudinal space being formed on said tubular bush; a block on which said sliding surface and said shoulder are formed, said block being insertable in said longitudinal space; and a duct for access of said filament to said feed channel that is formed in said block.
8. The extruder of claim 1, wherein said front part comprises a tubular body, having formed therein a transfer chamber; a screw feeder accommodated in said transfer chamber for feeding small pieces of said filament; and a melting chamber, said transfer chamber comprising a heat dissipation means which is constituted by heat dissipation fins formed on an outer surface of said transfer chamber.
9. The extruder of claim 1, wherein said front part comprises a tubular body; a melting chamber accommodated in said tubular body; and electric resistor means constituted by a helical resistor provided in said melting chamber.
10. The extruder of claim 1, further comprising a heating fan with an output duct; a tube; an output connector; an injection nozzle, said output duct being connected through said tube to said output connector that is arranged proximate to said injection nozzle.
11. The extruder of claim 1, wherein said front part comprises: an ejection duct; a screw feeder for the small pieces of plastic filament that are fed in said feeding direction from said rear part toward the ejection duct; an axial bearing of a conical roller type; and a rotation shaft; and wherein a rotation axis of said screw feeder coincides with an axis of said rotation shaft, which is keyed on said axial bearing.
12. The extruder of claim 1, wherein said front part comprises: an ejection duct; a melting chamber that is proximate to the ejection duct; a transfer chamber; a screw feeder located in said transfer chamber for transferring the small pieces of plastic filament along said feeding direction from said rear part, said transfer chamber comprising heat dissipation means, which are constituted by heat dissipation fins formed on an outer surface of said transfer chamber.
13. The extruder of claim 1, wherein said front part comprises: a melting chamber for the small pieces of plastic filament that are fed along said feeding direction from said rear part; electric resistor means provided in said melting chamber for melting said small pieces of filament, said electric resistor means comprising a helical resistor mounted in said melting chamber coaxial to said melting chamber.
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 system for use in developing risk management software, said system comprising an object-oriented library of library objects stored on a computer-readable storage medium, said library comprising:
(a) a first plurality of library objects for use in generating scenarios data, comprising a plurality of generators passable to at least one software component that requires data provided by said generators, wherein each of said plurality of generators produces elements of a sequence governed by a sequential process, wherein each generator comprises a common generator interface, where said common generator interface comprises a first function that generates the next element of said sequence and a second function that returns the element most recently generated by said first function;
(b) a second plurality of library objects for calculating instrument values, comprising at least one of
i. a plurality of maps, wherein each map comprises a common map interface, wherein said common map interface comprises a third function that receives as input a first object of a first type, transforms said first object according to a pre-defined rule to produce a second object of a second type, and returns said second object, and
ii. a plurality of accumulators, wherein each accumulator comprises an internal state and a common accumulator interface, said internal state having a current value, said current value being a function of one or more past values of said internal state and one or more data values received as input by said accumulator, said common accumulator interface comprising a fourth function to receive as input said one or more data values and to update said internal state to a new current value, and a fifth function that returns a value corresponding to the current value of the internal state; and
(c) a third plurality of library objects comprising a plurality of operations, said plurality of operations defined to operate on at least one generator of said plurality of generators and at least one other operand in an expression to produce a new generator;
said new generator for use in performing a simulation to obtain prices for a plurality of instruments over a plurality of scenarios.
2. The system as claimed in claim 1, wherein each generator is adapted to produce elements of either a deterministic or stochastic sequence.
3. The system as claimed in claim 1, wherein said other operand is selected from the following group: a generator; a map; an accumulator; and objects of compatible type such that said arithmetic expression is defined.
4. The system as claimed in claim 1, wherein said expression is an arithmetic expression comprising one or more of the arithmetic operations selected from the following group: addition, subtraction, multiplication, and division.
5. The system as claimed in claim 1, wherein said expression comprises a composition operation.
6. A method of developing risk management software using objects from an object-oriented library, said software comprising instructions for simulating a portfolio of financial instruments over a plurality of scenarios, said method comprising the steps of:
(a) constructing a scenario generator passable to at least one software component that requires data provided by said scenario generator, wherein said scenario generator produces elements of a sequence governed by a sequential process, wherein said scenario generator comprises a common generator interface, and wherein said common generator interface comprises a first function that generates the next element of said sequence and a second function that returns the element most recently generated by said first function;
(b) constructing one or more pricing maps, wherein each pricing map is associated with an instrument in a portfolio, wherein each pricing map comprises a common map interface, wherein said common map interface comprises a third function that receives as input a first object of a first type, transforms said first object according to a pre-defined rule to produce a second object of a second type, and returns said object;
(c) composing said one or more pricing maps with said scenario generator to obtain a pricing generator; and
(d) using said pricing generator in performing a simulation to obtain prices for a plurality of instruments.
7. The method as claimed in claim 6, wherein step (c) comprises the steps of composing said one or more pricing maps to produce a composite pricing map, and composing said composite pricing map with said scenario generator to obtain a pricing generator.
8. The method as claimed in claim 6, wherein said prices for said plurality of instruments are used to populate a Mark-to-Future cube.
9. A method of developing risk management software using objects from an object-oriented library, said software comprising instructions for simulating a portfolio of financial instruments over a plurality of scenarios, said method comprising the steps of:
(a) constructing a stochastic sequence generator passable to at least one software component that requires data provided by said scenario generator, wherein said stochastic sequence generator produces elements of a sequence governed by a sequential process, wherein said stochastic sequence generator comprises a common generator interface, where said common generator interface comprises a first function that generates the next element of said sequence and a second function that returns the element most recently generated by said first function;
(b) constructing one or more pricing accumulators, wherein each pricing accumulator is associated with an instrument in a portfolio, wherein each pricing accumulator comprises an internal state and a common accumulator interface, said internal state having a current value, said current value being a function of one or more past values of said internal state and one or more data values received as input by said accumulator, said common accumulator interface comprising a third function to receive as input said one or more data values and to update said internal state to a new current value, and a fourth function that returns a value corresponding to the current value of the internal state;
(c) composing said one or more pricing accumulators with said stochastic sequence generator to obtain a pricing generator;
(d) using said pricing generator in performing a simulation to obtain prices for a plurality of instruments at each time step in a scenario; and
(e) repeating step (d) over a plurality of scenarios.
10. The method as claimed in claim 9, wherein step (c) comprises the steps of composing said one or more pricing accumulators to produce a composite pricing accumulator, and composing said composite pricing accumulator with said stochastic sequence generator to obtain a pricing generator.
11. The method as claimed in claim 9, wherein said prices for said plurality of instruments are used to populate a Mark-to-Future cube.
12. The method as claimed in claim 9, wherein step (e) is performed by cloning said pricing generator.