This invention relates to a wire handling apparatus.
Wires are typically manufactured in bulk and stored on wire carriers such as spools. Wire is often fed from a spool by pulling on a free end of the wire (e.g., using a pinch-roller system), rotating the spool itself (e.g., using a motor coupled to the pool), or both. Conventional wire handling apparatuses are designed to handle relatively low gauge (large diameter) wire.
In a general aspect, wire handling tool includes a frame, a first actuator having a proximal end attached to the frame and a first distal end including a first grasping member for grasping a wire, the first distal end configured to move along a first axis, wherein movement of the first distal end causes movement of the grasped wire along the first axis, and a controller for controlling the first actuator according to a wire feeding sequence to move the wire along the first axis.
Aspects may include one or more of the following features.
The first actuator may be movable between a first configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator disengaged from the wire, the first distal end of the first actuator being disposed at a first position on the first axis, a second configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator grasping the wire, the first distal end of the first actuator being disposed at the first position on the first axis, a third configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator grasping the wire, the first distal end of the first actuator being disposed at a second position on the first axis, and a fourth configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator disengaged from the wire, the first distal end of the first actuator being disposed at the second position on the first axis. A transition between the second configuration and the third configuration causes movement of the wire along the first axis.
The first actuator may include a number of sub-actuators, each sub-actuator of the number of sub-actuators having a proximal end attached to the frame and a distal end including a grasping element, wherein the corresponding grasping elements of the number of elongate sub-actuators form the first grasping member. The distal end of each sub-actuator of the number of sub-actuators may be configured to move in a number of directions including a direction along the first axis and a direction transverse to the first axis. Each sub-actuator of the number of sub-actuators may include an elongate piezoelectric actuator configured move the distal end of the sub-actuator by bending in response to an electrical stimulus.
The wire handling tool may include a second actuator having a second proximal end attached to the frame and a second distal end including a second grasping member for grasping the wire, the second distal end configured to move along the first axis, wherein movement of the second distal end causes movement of the grasped wire along the first axis, and the controller is further configured to control the second actuator according to the wire feeding sequence to move the wire along the first axis.
The first actuator and the second actuator may be movable between a first configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator disengaged from the wire and the second grasping member of the second distal end of the second actuator grasping a first portion of the wire, the second distal end being disposed at a first position on the first axis, a second configuration of the wire feeding sequence with the first grasping member of the first distal end of the first actuator disengaged from the wire and second grasping member of the second distal end of the second actuator grasping the first portion of the wire, the second distal end being disposed at a second position on the first axis, a third configuration of the wire feeding sequence with the second grasping member of the second distal end of the second actuator disengaged from the wire and first grasping member of the first distal end of the first actuator grasping a second portion of the wire, the first distal end being disposed at a third position on the first axis, and a fourth configuration of the wire feeding sequence with the second grasping member of the second distal end of the second actuator disengaged from the wire and the first grasping member of the first distal end of the first actuator grasping the second portion of the wire, the first distal end being disposed at a fourth position on the first axis. A transition from the first configuration to the second configuration causes movement of the wire along the first axis and a transition from the third configuration to the fourth configuration may cause movement of the wire along the first axis.
The first actuator may include a first number of sub-actuators, each sub-actuator of the first number of sub-actuators having a proximal end attached to the frame and a distal end including a grasping element, wherein the corresponding grasping elements of the first number of elongate sub-actuators form the first grasping member and the second actuator includes a second number of sub-actuators, each sub-actuator of the second number of sub-actuators having a proximal end attached to the frame and a distal end including a grasping element, wherein the corresponding grasping elements of the second number of elongate sub-actuators form the second grasping member. The distal end of each sub-actuator of the first number of sub-actuators may be configured to move in a first number of directions including a direction along the first axis and a direction transverse to the first axis and the distal end of each sub-actuator of the second number of sub-actuators may be configured to move in a second number of directions including a direction along the first axis and a direction transverse to the first axis.
Each sub-actuator of the first number of sub-actuators may include an elongate piezoelectric actuator configured move the distal end of the sub-actuator by bending in response to an electrical stimulus and each sub-actuator of the second number of sub-actuators may include an elongate piezoelectric actuator configured move the distal end of the sub-actuator by bending in response to an electrical stimulus. The wire handling tool may include a substantially cylindrical elongate nozzle coupled to the frame and extending along the first axis, the nozzle having a channel extending therethrough for receiving the wire. A sidewall of the nozzle may include an opening through which the first grasping member extends for accessing the wire.
The wire handling tool may include a wire stripping apparatus including a second frame with a first wire stripping blade attached thereto and a wire stripping actuator having a proximal end attached to the second frame and a distal end with a second wire stripping blade attached thereto, wherein the first wire stripping blade opposes the second wire stripping blade. The controller may be further configured to control the wire stripping actuator according to a wire stripping sequence. The wire handling tool may include a rotation actuator for grasping and rotating the wire. The wire handling tool may include a bonding member for attaching the wire to a surface.
In another general aspect, a wire handling tool includes a frame, a contact surface, an actuator having a proximal end attached to the frame and a distal end, the distal end configured to move in a direction along a first axis and configured to move in a direction transverse to the first axis for pressing the wire against the contact surface. Movement of the distal end along the first axis when the wire is pressed against the contact surface causes movement of the wire along the first axis. The wire handling tool includes a controller for controlling the actuator according to a wire feeding sequence to move the wire along the first axis.
Aspects may include one or more of the following features.
The actuator may be movable between a first configuration of the wire feeding sequence with the distal end of the actuator disengaged from the wire, the distal end of the actuator being disposed at a first position along the first axis, a second configuration of the wire feeding sequence with the distal end of the actuator pressing the wire against the contact surface, the distal end of the actuator being disposed at the first position along the first axis, a third configuration of the wire feeding sequence with the distal end of the actuator pressing the wire against the contact surface, the distal end of the actuator being disposed at a second position along the first axis, and a fourth configuration of the wire feeding sequence with the distal end of the actuator disengaged from the wire, the distal end of the actuator being disposed at the second position along the first axis. Transitioning between the second configuration of the wire feeding sequence and the third configuration of the wire feeding sequence may cause movement of the wire along the first axis.
The distal end of the actuator may be configured to move in a first number of directions including a direction along the first axis and a direction transverse to the first axis. The actuator may include an elongate piezoelectric actuator, the elongate piezoelectric actuator configured move the distal end of the first by bending in response to an electrical stimulus and each sub-actuator of the second number of sub-actuators may include an elongate piezoelectric actuator configured move the distal end of the sub-actuator by bending in response to an electrical stimulus.
In another general aspect, a method for feeding, stripping, and bonding a wire, includes feeding a first portion of wire from a spool using a first wire handling tool, the first wire handling tool being configured according to some or all of the features described above, cutting the first portion of wire using a wire cutting tool attached to the first wire handling tool, grasping the first portion of wire using a second wire handling tool, the second wire handling tool being configured according to some or all of the features described above, moving the first portion of wire to a wire stripping apparatus using the second wire handling tool and stripping a first end of the first wire portion of wire using the wire stripping apparatus, grasping the first wire portion using a wire rotation apparatus and releasing the first portion of wire from the second wire handling tool, rotating the first portion of wire using the wire rotation apparatus, grasping the rotated first portion of wire using the second wire handling apparatus, moving the first portion of wire to the wire stripping apparatus using the second wire handling tool and stripping a second end of the first wire portion using the wire stripping apparatus, moving the second end of the first portion of wire to a first connection point using the second wire handling apparatus and attaching the second end of the first portion of wire to the first connection point using a bonding apparatus, and moving the first end of the first portion of wire to a second connection point using the second wire handling apparatus and attaching the first end of the first portion of wire to the second connection point using the bonding apparatus.
The first wiring tool may include a frame, a first actuator having a proximal end attached to the frame and a first distal end including a first grasping member for grasping a wire, the first distal end configured to move along a first axis, wherein movement of the first distal end causes movement of the grasped wire along the first axis, and a controller for controlling the first actuator according to a wire feeding sequence to move the wire along the first axis, and the second wiring tool may include a second actuator having a proximal end attached to the frame and a second distal end including a second grasping member for grasping a wire, the second distal end configured to move along a second axis, wherein movement of the second distal end causes movement of the grasped wire along the second axis, and a controller for controlling the second actuator according to a wire feeding sequence to move the wire along the second axis.
Aspects may have one or more of the following advantages.
Among other advantages, a wire handling apparatus and its method of use employs one or more piezoelectric actuators to precisely feed high gauge wire. The one or more piezoelectric actuators are controlled according to a wire feeding sequence. The wire feeding sequence causes the piezoelectric actuators to interact with and manipulate the wire such that a desired length of wire is precisely fed. Furthermore, the wire handling apparatus can be used to automate wiring of microelectronic circuitry.
Other features and advantages of the invention are apparent from the following description, and from the claims.
Referring to
The wire handling apparatus 100 includes a frame 108 with a feed nozzle 112 as well as a first actuator 111 and a second actuator 113 attached thereto. Each of the first actuator 111 and the second actuator 113 includes two elongate two-dimensional (2D) piezoelectric actuators 114. Each of the 2D piezoelectric actuators 114 extends in a direction along a first axis 132 from a proximal end 116 of the 2D piezoelectric actuator 114 to a distal end 118 of the 2D piezoelectric actuator 114. The proximal end 116 of each of the 2D piezoelectric actuators 114 is attached to the frame 108 in proximity to the proximal end 102 of the wire handling apparatus 100.
The distal end 118 of each of the 2D piezoelectric actuators 114 is free and has a grasping member 120 disposed thereon. The feed nozzle 112 is an elongate tubular member extending through and affixed to the frame 108 in proximity to the distal end 104 of the wire handling apparatus 100. The feed nozzle includes a channel extending therethrough in a direction along a feeding axis 130. The wire 106 extends through the channel in the feed nozzle 112 in a direction along the feeding axis 130.
Referring to
Each of the grasping members 120 at the distal ends 118 of the 2D piezoelectric actuators 114 includes a finger 124 extending into the cut-out portion 122 of the feed nozzle 112 for interacting with the wire 106 in the cut-out portion 122.
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In a first step (1) of the wire feeding sequence 334, a first voltage is applied to the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators 114 of the first actuator 111 to bend in a direction toward the wire 106. With the 2D piezoelectric actuators 114 of the first actuator 111 bent, the fingers 122 of the grasping elements 120 at the distal ends 118 of the 2D piezoelectric actuators 114 of the first actuator 111 grasp the wire 106. The 2D piezoelectric actuators 114 of the second actuator 113 remain unbent and the second actuator 113 does not engage the wire 106 in the first step (1).
In a second step (2) of the wire feeding sequence 334, a second voltage is applied to the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators 114 of the first actuator 111 to remain bent in a direction toward the wire 106 such that the wire 106 remains grasped between the fingers 122 of the grasping elements 120 of the first actuator 111 and causing the 2D piezoelectric actuators 114 of the first actuator 111 to bend in a direction in a feeding direction along the feeding axis 130. The second step (2) causes a one distance unit displacement the wire 106 along the feeding axis 130 along the feeding direction, as is illustrated by the reference point 336 on the wire 106 being advanced. The 2D piezoelectric actuators 114 of the second actuator 113 remain unbent and the second actuator 113 does not engage the wire 106 in the second step (2).
In a third step (3) of the wire feeding sequence 334, the first voltage is applied to the 2D piezoelectric actuators 114 of the second actuator 113, causing the 2D piezoelectric actuators 114 of the second actuator 113 to bend in a direction toward the wire 106. With the 2D piezoelectric actuators 114 of the second actuator 113 bent, the fingers 122 of the grasping elements 120 at the distal ends 118 of the 2D piezoelectric actuators 114 of the second actuator 113 grasp the wire 106. With the wire 106 grasped by the second actuator 113, voltage is removed from the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators to return to an unbent state where the first actuator does not engage the wire 106.
In a fourth step (4) of the wire feeding sequence 334, the second voltage is applied to the 2D piezoelectric actuators 114 of the second actuator 113, causing the 2D piezoelectric actuators 114 of the second actuator 113 to remain bent in a direction toward the wire 106 such that the wire 106 remains grasped between the fingers 122 of the grasping elements 120 of the second actuator 113 and causing the 2D piezoelectric actuators 114 of the second actuator 113 to bend in a direction in the feeding direction along the feeding axis 130. The fourth step (4) causes a one distance unit displacement the wire 106 along the feeding axis 130 along the feeding direction, as is illustrated by the reference point 336 on the wire 106 being advanced. The 2D piezoelectric actuators 114 of the first actuator 111 remain unbent and the first actuator 111 does not engage the wire 106 in the fourth step (4).
In a fifth step (5) of the wire feeding sequence 334, the first voltage is applied to the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators 114 of the first actuator 111 to bend in a direction toward the wire 106. With the 2D piezoelectric actuators 114 of the first actuator 111 bent, the fingers 122 of the grasping elements 120 at the distal ends 118 of the 2D piezoelectric actuators 114 of the first actuator 111 grasp the wire 106. The 2D piezoelectric actuators 114 of the second actuator 113 remain unbent and the second actuator 113 does not engage the wire 106 in the fifth step (5).
In a sixth step (6) of the wire feeding sequence 334, the second voltage is applied to the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators 114 of the first actuator 111 to remain bent in a direction toward the wire 106 such that the wire 106 remains grasped between the fingers 122 of the grasping elements 120 of the first actuator 111 and causing the 2D piezoelectric actuators 114 of the first actuator 111 to bend in a direction in a feeding direction along the feeding axis 130. The sixth step (6) causes a one distance unit displacement the wire 106 along the feeding axis 130 along the feeding direction, as is illustrated by the reference point 336 on the wire 106 being advanced. The 2D piezoelectric actuators 114 of the second actuator 113 remain unbent and the second actuator 113 does not engage the wire 106 in the sixth step (6).
In a seventh step (7) of the wire feeding sequence 334, the first voltage is applied to the 2D piezoelectric actuators 114 of the second actuator 113, causing the 2D piezoelectric actuators 114 of the second actuator 113 to bend in a direction toward the wire 106. With the 2D piezoelectric actuators 114 of the second actuator 113 bent, the fingers 122 of the grasping elements 120 at the distal ends 118 of the 2D piezoelectric actuators 114 of the second actuator 113 grasp the wire 106. With the wire 106 grasped by the second actuator 113, voltage is removed from the 2D piezoelectric actuators 114 of the first actuator 111, causing the 2D piezoelectric actuators to return to an unbent state where the first actuator does not engage the wire 106.
In an eighth step (8) of the wire feeding sequence 334, the second voltage is applied to the 2D piezoelectric actuators 114 of the second actuator 113, causing the 2D piezoelectric actuators 114 of the second actuator 113 to remain bent in a direction toward the wire 106 such that the wire 106 remains grasped between the fingers 122 of the grasping elements 120 of the second actuator 113 and causing the 2D piezoelectric actuators 114 of the second actuator 113 to bend in a direction in the feeding direction along the feeding axis 130. The eighth step (8) causes a one distance unit displacement the wire 106 along the feeding axis 130 along the feeding direction, as is illustrated by the reference point 336 on the wire 106 being advanced. The 2D piezoelectric actuators 114 of the first actuator 111 remain unbent and the first actuator 111 does not engage the wire 106 in the eighth step (8).
The wire feeding sequence 334 described above is one simple example of a wire feeding sequence where two actuators work in unison to advance the wire along a feeding direction while ensuring that at least one actuator is always grasping the wire such that the wire does not unintentionally retreat or advance due to factors such as inertia of the wire or the wire and spool. It is noted, however that many wire feeding sequences are possible. For example, the wire feeding sequence described above can be repeated to feed additional units of wire. Similarly, subsets of the wire feeding sequence described above can be used to feed fewer units of wire. In some examples, the 2D piezoelectric actuators described above and be moved with high frequency (e.g., 10 Hz-1000 Hz). In some examples, the wire feeding apparatus includes one or more sensors to measure an amount of wire that has been fed.
Referring to
The wire handling apparatus 500 includes a frame 508 with a single actuator 511 and a feed nozzle 512 attached thereto. The actuator 511 includes two elongate two-dimensional (2D) piezoelectric actuators 514. Each of the 2D piezoelectric actuators 514 extends in a direction along a first axis 532 from a proximal end 516 of the 2D piezoelectric actuator 514 to a distal end 518 of the 2D piezoelectric actuator 514. The proximal end 516 of each of the 2D piezoelectric actuators 514 is attached to the frame 508 in proximity to the proximal end 502 of the wire handling apparatus 500. The distal end 518 of each of the 2D piezoelectric actuators 514 is free and has a grasping member 520 disposed thereon. The feed nozzle 512 is an elongate tubular member extending through and affixed to the frame 508 in proximity to the distal end 504 of the wire handling apparatus 500. The feed nozzle includes a channel extending therethrough in a direction along a feeding axis 530. The wire 506 extends through the channel in the feed nozzle 112 in a direction along the feeding axis 530.
As was the case with the wire handling apparatus 100 of
Each of the grasping members 520 at the distal ends 518 of the 2D piezoelectric actuators 514 includes a finger 524 extending into the cut-out portion 522 of the feed nozzle 512 for interacting with the wire 506 in the cut-out portion 522.
Referring to
In a first step (1) of the wire feeding sequence 634, a first voltage is applied to the 2D piezoelectric actuators 514 of the actuator 511, causing the 2D piezoelectric actuators 514 of the actuator 511 to bend in a direction toward the wire 506. With the 2D piezoelectric actuators 514 of the actuator 511 bent, the fingers 522 of the grasping elements 520 at the distal ends 518 of the 2D piezoelectric actuators 514 of the actuator 511 grasp the wire 506.
In a second step (2) of the wire feeding sequence 634, a second voltage is applied to the 2D piezoelectric actuators 514 of the actuator 511, causing the 2D piezoelectric actuators 514 of the actuator 511 to remain bent in a direction toward the wire 506 such that the wire 506 remains grasped by the fingers 522 and causing the 2D piezoelectric actuators 514 of the actuator 511 to bend in a direction along the feeding axis 530. The second step (2) therefore causes a one distance unit displacement the wire 506 along the feeding axis 530, as is illustrated by the reference point 636 on the wire 506 being advanced.
In a third step (3) of the wire feeding sequence 634, voltage is removed from the 2D piezoelectric actuators 514 of the actuator 511, causing the 2D piezoelectric actuators 514 to return to an unbent state where the actuator 511 does not engage the wire 506.
In a fourth step (4) of the wire feeding sequence 634, the first voltage is applied to the 2D piezoelectric actuators 514 of the actuator 511, causing the 2D piezoelectric actuators 514 of the actuator 511 to bend in a direction toward the wire 506. With the 2D piezoelectric actuators 514 of the actuator 511 bent, the fingers 522 of the grasping elements 520 at the distal ends 518 of the 2D piezoelectric actuators 514 of the actuator 511 grasp the wire 506.
In a fifth step (5) of the wire feeding sequence 634, the second voltage is applied to the 2D piezoelectric actuators 514 of the actuator 511, causing the 2D piezoelectric actuators 514 of the actuator 511 to remain bent in a direction toward the wire 506 such that the wire 506 remains grasped by the fingers 522 and causing the 2D piezoelectric actuators 514 of the actuator 511 to bend in a direction along the feeding axis 530. The second step (5) therefore causes a second, one distance unit displacement the wire 506 along the feeding axis 530, as is illustrated by the reference point 636 on the wire 506 being advanced.
Referring to
The wire handling apparatus 700 includes a frame 708 with a single actuator 711 and a feed nozzle 712 attached thereto. The actuator 711 includes one elongate two-dimensional (2D) piezoelectric actuators 714 that is configured to interact with a stationary backstop 715 to feed the wire 706. The 2D piezoelectric actuator 714 extends in a direction along a first axis 732 from a proximal end 716 of the 2D piezoelectric actuator 714 to a distal end 718 of the 2D piezoelectric actuator 714. The proximal end 716 of the 2D piezoelectric actuator 714 is attached to the frame 708 in proximity to the proximal end 702 of the wire handling apparatus 700. The distal end 718 of the 2D piezoelectric actuator 714 is free and has a grasping member 720 disposed thereon. The backstop 715 is attached to the frame 708 proximate to the distal end of the wire handling apparatus 700 and is disposed opposite a side of the distal end 718 of the 2D piezoelectric actuator 714.
The feed nozzle 712 is an elongate tubular member extending through and affixed to the frame 708 in proximity to the distal end 704 of the wire handling apparatus 700. The feed nozzle 712 includes a channel extending therethrough in a direction along a feeding axis 730. The wire 706 extends through the channel in the feed nozzle 712 in a direction along the feeding axis 730.
As was the case with the wire handling apparatus 100 of
The grasping member 720 at the distal end 718 of the 2D piezoelectric actuator 714 includes a finger 724 extending into the cut-out portion 722 of the feed nozzle 712 for interacting with the wire 706 in the cut-out portion 722 to press the wire 706 against the backstop 715.
Referring to
In a first step (1) of the wire feeding sequence 834, a first voltage is applied to the 2D piezoelectric actuator 714 of the actuator 711, causing the 2D piezoelectric actuator 714 of the actuator 711 to bend in a direction toward the wire 706. With the 2D piezoelectric actuator 714 of the actuator 711 bent, the finger 722 of the grasping element 720 at the distal end 718 of the 2D piezoelectric actuator 714 of the actuator 711 presses the wire 706 against the backstop 715.
In a second step (2) of the wire feeding sequence 834, a second voltage is applied to the 2D piezoelectric actuator 714 of the actuator 711, causing the 2D piezoelectric actuator 714 of the actuator 711 to remain bent in a direction toward the wire 706 such that the wire 706 remains pressed against the backstop 715 and causing the 2D piezoelectric actuator 714 of the actuator 711 to bend in a direction along the feeding axis 730. In general, a coefficient of friction of the finger 722 of the grasping element 720 is substantially higher than a coefficient of friction of the backstop 715 (e.g., the backstop 715 is made of a Teflon-like material) such that the finger 722 causes movement of the wire 706 along the backstop 715 when the finger 722 is pressing the wire 706 against the backstop 715. The second step (2) therefore causes a one distance unit displacement the wire 706 along the feeding axis 730 along the feeding direction, as is illustrated by the reference point 836 on the wire 706 being advanced.
In a third step (3) of the wire feeding sequence 834, voltage is removed from the 2D piezoelectric actuator 714 of the actuator 711, causing the 2D piezoelectric actuator 714 to return to an unbent state where the actuator 711 does not engage the wire 706.
In a fourth step (4) of the wire feeding sequence 834, the first voltage is applied to the 2D piezoelectric actuator 714 of the actuator 711, causing the 2D piezoelectric actuator 714 of the actuator 711 to bend in a direction toward the wire 706. With the 2D piezoelectric actuator 714 of the actuator 711 bent, the finger 722 of the grasping element 720 at the distal end 718 of the 2D piezoelectric actuator 714 of the actuator 711 presses the wire 706 against the backstop 715.
In a fifth step (5) of the wire feeding sequence 834, the second voltage is applied to the 2D piezoelectric actuator 714 of the actuator 711, causing the 2D piezoelectric actuator 714 of the actuator 711 to remain bent in a direction toward the wire 706 such that the wire 706 remains pressed against the backstop 715 and causing the 2D piezoelectric actuator 714 of the actuator 711 to bend in a direction along the feeding axis 730. The fifth step (5) causes a second, one distance unit displacement the wire 706 along the feeding axis 730 along the feeding direction, as is illustrated by the reference point 836 on the wire 706 being advanced.
Referring to
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The first wire handling apparatus 940 feeds a desired length of wire 906 from the spool 940. In some examples, the length of wire 906 is fed through the second wire handling apparatus 946 while the second wire handling apparatus 946 remains disengaged from the wire 906. In some examples, the second wire handling apparatus 946 assists the first wire handling apparatus 940 in feeding the desired length of wire 906. With the desired length of wire 906 successfully fed, the second wire handling apparatus 946 grasps the wire 906 and the wire cutter 944 cuts the wire 906.
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It is to be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments are within the scope of the following claims.
This application claims the benefit of U.S. Provisional Application 62/544,279, filed on Aug. 11, 2017, the contents of which is incorporated herein by reference.
Number | Date | Country | |
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62544279 | Aug 2017 | US |