Patent US3749535A successfully refreshed from Google Patents.
US3749535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for extrusion of plastic net
Assignee: Leucadia Inc
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Filing: 1971-10-14
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Granted: 1973-07-31
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Expires: 1991-10-14
Abstract
Abstract An extrusion apparatus, having two die members which are moved relative to one another to extrude a plurality of spaced strands of plastic material in one direction and a plurality of spaced strands in a second direction to form an integral net or net-like structure is operated by generating a first electrical signal having a wave form correlated to a desired motion of the die members, monitoring the actual motion of the die members and generating a second electrical signal having a wave form corresponding thereto, comparing the first and second signals and generating a variable third signal adjusted to compensate for detected differences between the first and second signals, and transmitting the third signal to a torque motor-servo valve combination which controls flow of oil to a hydraulic cylinder piston assembly operatively connected to one or both of the die members for carrying out the desired motion thereof. The motion is carried out with a high order of precision and reproducibility enabling the extrusion of a wide variety of sizes and shapes of plastic net or similar structures.
Inventors
- 👤 B Gaffney
- 👤 R Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:46
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/30; B29C48/301; B29C48/03; B29C48/05; B29C48/09; B29C48/10; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92019; B29C2948/92076; B29C2948/92085; B29C2948/92504; B29C2948/92514; B29C2948/92561; B29C2948/92571; B29C2948/9258; B29C2948/92809; B29C2948/92819; B29C2948/92857; B29C2948/92904; B29C48/07; B29C48/08; B29C48/11; B29C48/13; B29L; B29L2028/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
311 words
In an extrusion apparatus for manufacture of plastic net like structures, having two die members which are reciprocably displaceable relative to each other between two different positions, in one of which a plurality of spaced streams of flowing molten thermoplastic material is extruded and in the other of which an additional stream of said material integral with and transverse to said spaced streams is extruded, the improvements comprising: a. means for holding one of said die members in a stationary position; b. means for moving the other said die member to displace it relative to said stationary die member between said two positions, said moving means including: 1. a hydraulic cylinder, 2. a double-faced piston within said cylinder and connected to said movable die member, 3. means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrical signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 2
Dependent Claim
311 words
In an extrusion apparatus for manufacture of plastic net like structures, having two die members which are reciprocably displaceable relative to each other between two different positions, in one of which a plurality of spaced streams of flowing molten thermoplastic material is extruded and in the other of which an additional stream of said material integral with and transverse to said spaced streams is extruded, the improvements comprising: a. means for holding one of said die members in a stationary position; b. means for moving the other said die member to displace it relative to said stationary die member between said two positions, said moving means including: 1. a hydraulic cylinder, 2. a double-faced piston within said cylinder and connected to said movable die member, 3. means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrical signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 3
Dependent Claim
13 words
a double-faced piston within said cylinder and connected to said movable die member,
Claim 4
Dependent Claim
13 words
a double-faced piston within said cylinder and connected to said movable die member,
Claim 5
Dependent Claim
13 words
a double-faced piston within said cylinder and connected to said movable die member,
Claim 6
Dependent Claim
13 words
a double-faced piston within said cylinder and connected to said movable die member,
Claim 7
Dependent Claim
69 words
In an extrusion apparatus for manufacture of plastic net like structures, having two die members which are reciprocably displaceable relative to each other between two different positions, the improvement comprising: a. means for holding one of said die members in a stationary position; b. means for moving the other said die member to displace it relative to said stationary die member between said two positions, said moving means including:
Claim 8
Dependent Claim
69 words
In an extrusion apparatus for manufacture of plastic net like structures, having two die members which are reciprocably displaceable relative to each other between two different positions, the improvement comprising: a. means for holding one of said die members in a stationary position; b. means for moving the other said die member to displace it relative to said stationary die member between said two positions, said moving means including:
Claim 9
Dependent Claim
185 words
means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrical signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 10
Dependent Claim
185 words
means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrical signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 11
Dependent Claim
22 words
The apparatus of claim 2 in which said hydraulic pump means delivers two independent pressure hydraulic fluids to said servo valve means.
Claim 12
Dependent Claim
185 words
means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrial signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 13
Dependent Claim
185 words
means for applying fluid pressure upon one face of said piston to move said movable die member in one direction and for applying fluid pressure to the opposite face of said piston to move said movable die member in reverse direction said means for applying fluid pressure comprising i. means for generating an electrical signal, ii. comparator means for comparing the generated electrical signal with an electrical signal indicating the actual motion of the die whereby an adjusted signal is generated by said comparator means, iii. means comprising servo valve means for converting said adjusted signal to a hydraulic signal, and iv. hydraulic pump means independent of said generated electrical signal, said electrial signal indicating the actual motion of the die, and said adjusted signal for communicating hydraulic fluid under constant pressure to said servo valve; and c. generator means for generating said electrical signal indicating the actual motion of the die, said generator means comprising a transducer connected to said double-faced piston; and d. means for transmitting said electrical signal indicating the actual motion of the die from the transducer to the comparator means.
Claim 14
Dependent Claim
22 words
The apparatus of claim 1 in which said hydraulic pump means delivers two independent pressure hydraulic fluids to said servo valve means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |