AN INSULATION COVERING STRIPPING DEVICE

Abstract: An insulation covering stripping device (17) for use in combination with automatic apparatus for manufacturing electrical harnesses has a moving chuck (12) for pulling out insulation clad wires (2) to a desired length so that the insulation covering stripping is carried out as the same time as the lengths of the wires (2) are measured, thereby shortening the operation time of manufacturing electrical harnesses.

Description: The invention relates to an insulation covering stripping device for removing insulation covering of wires, wherein the wires are assembled as an electrical harness with a contact-type connector at one end thereof, and with the other ends of the wires being free from a connector. The insulation covering stripping device, hereinafter referred to merely as the stripping device, is particularly suitable for use in association with automatic apparatus for manufacturing electrical harnesses. Recently semi-automatic or fully automatic apparatus for producing such harnesses has been developed, typical examples of which are disclosed in Japanese Patent Kokai (unexamined Publication) No. 58(1983)-145080, U.S. Patent No. 4,136,440 and U.S. Patent No. 4,310,967. The finished electrical harness has electrical conductors covered with an insulation covering at its connector-free end, and when the harness is used, it is necessary to remove the insulation covering so that the electrical conductors can be connected to circuits and instruments. To remove the insulation covering automatically, a stripping device is provided in the system for manufacturing electrical harnesses. Under the conventional system; however, the stripping process is carried out independently of the other processes, such as the wire length measuring process and the connector attaching process. In order to shorten the operation time, it is desirable for the stripping process to be carried out at the same time as when other processes are performed. Furthermore, it is desirable that the uncovered electrical conductors can have varying lengths. The conventional stripping device is however constructed so as to remove the insulation covering to one predetermined length. This is sometimes inconvenient; since for example, when a conductor is to be soldered it need be only about 5 mm in length, whereas, when it is to be wrapped, it is required to be as long as 20 to 30 mm since otherwise wrapping would be impossible. European Patent Application no. 0000428 discloses apparatus for making electrical harnesses in which a pair of independently moveable chucks co-operate with one another; with wire length varying apparatus including vertically extendable wire engaging members for withdrawing the free ends of the wires of the harness to varying degrees; with a wire cutting block; with connector attaching apparatus; and with an insulation covering stripping blade, to produce harnesses. However, this arrangement can only adjust the lengths of insulation covering to be stripped by limited amounts, and because the connector attaching apparatus is fixed relative to the wire cutting blade, harness lengths can only be adjusted discretely by re-siting the connector apparatus. U.S. patent no. 431096 discloses a similar apparatus, in which the connector attaching apparatus is mounted on a moveable chuck and serves to draw the wires of the harness from the supply spools. However, the operation of this device is such that the connector attaching apparatus apparently only draws wires in discrete lengths. According to the invention there is provided an insulation covering stripping device for use in combination with automatic apparatus for making electrical harnesses, the apparatus comprising a wire feed path extending substantially horizontally and axially of the apparatus; a connector attaching device and a connector supplying device therefor; a wire cutting blade located adjacent the connector attaching device; a first chuck reciprocally moveable along the wire feed path for pulling out wires forwardly for a distance corresponding to the length of the electrical harness; a second chuck for holding the supplied wires laterally at equal intervals and guiding the wires to the connector attaching device, the second chuck being reciprocally moveable along the wire feed path in a small range to align the forward ends of the wires prior to stripping; and a stripping length varying device including a plurality of members extendable vertically to engage the wires and withdraw their free ends by predetermined distances backwards from the first chuck, thereby to differentiate the lengths of the end portions of the wires to be stripped, the insulation covering stripping device comprising a third chuck reciprocally moveable along the wire feed path between the first and second chucks, to grip the wires when the first and second chucks are open and thereby adjust the lengths of the insulation covering to be stripped from the wires; and a stripping blade incorporated in the first chuck and moveable relative to the first chuck to strip insulation covering from the wires while the wires are being pulled out forwardly by the first chuck, thereby to reduce the time taken to make a harness; and to permit the making of harnesses of any of a continuous range of lengths. Such an insulation covering stripping device can vary the lengths of the insulation covering to be stripped from wire to wire in accordance with the purposes for which the electrical harness is required. The invention is diagrammatically illustrated by way of example with reference to the accompanying drawings, in which:- Figure 1 is a diagrammatic front view showing apparatus for making electrical harnesses including a stripping device according to one embodiment of the invention; Figure 2 is a vertical cross-section on a larger scale showing a main section of a connector attaching device shown in Figure 1; Figures 3 and 4 are cross-sectional views on a larger scale showing the operating states of the main section shown in Figure 2; Figure 5(a) and (b) are partially cross-sectional views showing two aspects of the operating states of a first movable chuck shown in Figure 1; Figures 6 and 7 are diagrammatic views showing the operating states of a stripping device mounted on the chuck of Figure 5; Figures 8(a) to (f) are diagrammatic views showing the operating steps of a connector attaching operation; Figures 9(a) and (b) are diagrammatic views showing the operating steps of a modified connector attaching operation; and Figures 10 and 11 are schematic views showing finished electrical harnesses . Referring to the drawings and firstly to Figure 1, apparatus for manufacturing electrical harnesses includes a wire supplying device 10 which supplies wires 2 horizontally in parallel by means of a bundling device 5, the wires 2 being supplied along a wire feed path W through a straightener 6 and a feed roller 7. A connector attaching device 11 is provided for attaching connectors 3 to the ends of the wires 2 by means of a punch 21 and a die 22 disposed on opposite sides of the wire feed path W, the punch and die having a cutting blade 23 located adjacent thereto. A connector supplying device (not shown) supplies connectors to the die 22 one by one. A first movable chuck 12 carries the wires 2 supplied to the connector attaching device 11 along the wire feed path W for a desired distance, whereby the desired length of the wires 2 is determined, and a second movable chuck 13 holds the wires 2 horizontally at equal intervals in parallel and guides the wires 2 to the connector assembling device 11 at which the second chuck 13 adjusts the positions of the wire ends. The second chuck 13 reciprocally moves in a predetermined relatively small range. The apparatus further includes a third movable chuck 14 provided between the second chuck 13 and the connector attaching device 11 and movable in a predetermined range along the wire feed path W. A device for determining the lengths of insulation covering to be stripped, hereinafter referred to as the stripping length varying device 15, is located between the second and third chucks 13 and 14. A stripping device 17, for removing the insulation covering of the wires 2, is on the first chuck 12. The connector supplying device includes a conventional hopper feeder and a magazine of a usual type, the description of which will be omitted for simplicity. The punch 21 is mounted on a slider 25 which can be raised and lowered by means of a pneumatic cylinder 24, and is lowered from the raised position shown in Figure 2 to the lowered position shown in Figures 3 and 4 to cause the connectors to be attached to the wire ends. The cutting blade 23 is also mounted on the slider 25, and is operated by means of a pneumatic cylinder 26 fixed to the slider 25, independently of the punch 21. The cutting blade 23 cuts the wires at the preparatory position for connector attachment in co-operation with a cutting die 27. In addition, the slider 25 has a wire chuck 28 for holding the wires at the moment of connector attachment, and a wire guide 29. The die 22 is mounted on a slider 30, which can be raised and lowered by two steps by means of a first pneumatic cylinder 31 and a second cylinder 32 coupled to the first cylinder 31 through a joint 33 in such a manner that they can move together. The die 22 moves together with the slider 30 and, in operation, the die 22 is raised from the position shown in Figure 2 together with the slider 30 by means of the first pneumatic cylinder 31 until it reaches the preparatory position for connector attachment shown in Figure 3. From the preparatory position it is further raised to the position shown in Figure 4 where the connectors are attached to the wire ends. A connector presser 34 is provided at the release side of the die 22, the connector presser 34 securing the connector 3 under the pressure of a spring (not shown). The connector presser 34 has a further wire chuck 35 located adjacent thereto, which mates with the wire chuck 28. The wire chuck 35 is operated by means of a pneumatic cylinder 36 mounted on the slider 30, independently of the die 22; it is raised from the preparatory position shown in Figure 3 and, in co-operation with the wire chuck 28, grips the wires pulled to a predetermined length by the chuck 12. As shown in Figure 5, the first chuck 12 includes a movable frame 40, and two pneumatic cylinders 41, 42 fixed to the movable frame 40. The two pneumatic cylinders 41 and 42 are coaxially provided, and the piston rod 44 of the cylinder 42 passes through a piston rod 43 of the cylinder 41. A pair of arms 45 are pivotally fixed to the movable frame 40 at their middle portions by pivot pins 46. Each arm 45 is provided with a chuck tooth 47 at its free end, and with a link 48 at its tail end, the link 48 being connected to the piston rod 43 so that the chuck teeth 47 can be opened and closed by means of the pneumatic cylinder 41. The movable frame 40 can be reciprocally moved along the wire feed path W. The stripping device 17 mounted on the first chuck 12 includes a pair of sliders 50, and a stripping blade 51 fixed at the free ends of each slider 50. Each slider 50 is slidably engaged in a dovetail groove 52 provided in an inner side of a respective one of the arms 45, and links 53 fixed to inner end portions of the sliders 50 are coupled to a connecting member 54 mounted on the free end of the piston rod 44. The sliders 50 can thus be reciprocally moved along the dovetail grooves 52 by means of the pneumatic cylinder 42. The sliders 50 move with the arms 45 so that as the chuck teeth 47 open or close the stripping blades 51 are opened and closed. The second chuck 13 can be opened and closed by means of a pneumatic cylinder 55, and can be reciprocally moved along the wire feed path W between the full line position and the dotted line position shown in Figure 1, a relatively small range, by a pneumatic cylinder 56. The third chuck 14 can be opened and closed by means of a pneumatic cylinder 58 and is movable along the wire feed path W as shown in Figure 1 by a pneumatic cylinder 59. Reference numerals 57 and 60 denote wire guides. The stripping length varying device 15 includes a plurality of varying plates 61, which are arranged laterally in such a manner that one plate corresponds to one wire, and which are individually capable of ascending and descending; a pneumatic cylinder 62 for moving the varying plates 61 as a whole up and down, and a pair of guide rollers 63, the pair of guide rollers 63 and the varying plate 61 being juxtaposed on opposite respective sides of the wire feed path W. The reference numeral 64 denotes a straightener located adjacent to the stripping length varying device 15, so as to straighten up the wires bent by the varying plates 61. The wire length varying device 16 includes a plurality of varying plates 65; a pneumatic cylinder 66 for moving the varying plates 65 up and down, and guide rollers 67, which are provided on a carrier 68 which can be moved up and down by means of a pneumatic cylinder 69. This enables the guide rollers 67 to descend below the path of the first chuck 12. An example of the operation will be described with reference to Figure 8: Figure 8 shows the steps of attaching the connectors to the wires. In Figure 8(a) the wires 2 have been supplied to the connector attaching device 11 by means of the feed roller 7 and by way of the second and third chucks 13 and 14. At first the wires 2 are pulled backward by the chuck 13 so as to align the free ends thereof with a desired point R. At this stage the first chuck 12 is shifted to a position under the punch 21. The second chuck 13 is kept open, and the third chuck 14, while gripping the wires 2, is caused to advance for a distance corresponding to the longest insulation covering to be stripped. (Figure 8(b)) Then, as shown in Figure 8(c), the wires 2 are released from the third chuck 14, and gripped by the second chuck 13. At this stage the stripping length varying device 15 is operated, thereby causing the individual varying plates 61 to descend so as to bulge the wires 2 downward. As a result, the free ends of the wires are withdrawn by different lengths according to the amount by which they have been bulged downwardly. Then, the first chuck 12 is operated, and grips the free ends of the wires 2 by means of the chuck teeth 47. At the same time the stripping blades 51 slit the insulation coverings of the wires. (Figure 8(d)) The first chuck 12 is advanced along the wire feed path W to pull the wires to a desired length. During the pulling travel the stripping device 17 is operated to move the stripping blades 51 away from the chuck teeth 47, thereby stripping the insulation covering off the conductor. (Figure 8(e)) As best shown in Figures 6 and 7, the lengths of the stripped conductors vary, which is derived from the fact that the position of the top ends of the wires 2 are differentiated in accordance with the lengths to be stripped. Then, the connector attaching device 11 is operated: At the preparatory position shown in Figure 3 the wire cutting blade 23 is lowered to cut the wires 2 in co-operation with the die 27, and the wires are pinched by the second chuck 13 until the cut ends thereof are positioned at the point R. Then the assembling die 22 is raised up to the connector assembling position shown in Figure 4, and the connector 3 is attached to the cut ends of the advancing wires 2A. (Figure 8(f)) Then the assembling punch 21 is raised, and the assembling die 22 is lowered, thereby allowing the connector 3 attached to the wire ends to be released from the die 22. The wires 2A are further withdrawn by the first chuck 12, and discharged out of the apparatus. The operation can then be repeated. As a result of the series of operation the wires 2A are cut to predetermined lengths, and are provided with one connector 3 at one end, with the other ends, being free from a connector, having lengths of insulation stripped from the conductors. A harness 9 l shown in Figure 11 can be formed by slackening the wires by means of the varying plates 65 in the aforementioned manner.

Claims: An insulation covering stripping device for use in combination with apparatus for making electrical harnesses, the apparatus comprising a wire feed path (W) extending substantially horizontally and axially of the apparatus; a connector attaching device (11) and a connector supplying device therefor; a wire cutting blade (23) located adjacent the connector attaching device; a first chuck (12) reciprocally moveable along the wire feed path (W) for pulling out wires forwardly for a distance corresponding to the length of the electrical harness; a second chuck (13) for holding the supplied wires laterally at equal intervals and guiding the wires to the connector attaching device, the second chuck being reciprocally moveable along the wire feed path in a small range to align the forward ends of the wires prior to stripping; and a stripping length varying device including a plurality of members extendable vertically to engage the wires and withdraw their free ends by predetermined distances backwards from the first chuck, thereby to differentiate the lengths of the ends portions of the wires to be stripped, insulation covering stripping device comprising (i) a third chuck (14) reciprocally moveable along the wire feed path (W) between the first (12) and second (13) chucks, to grip the wires when the first (12) and second (13) chucks are open and thereby adjust the lengths of the insulation covering to be stripped from the wires; and (ii) a stripping blade (51) incorporated in the first chuck and moveable relative to the first chuck to strip insulation covering from the wires while the wires are being pulled out forwardly by the first chuck.

Inventors: MATSU'URA, YUKITO, OKAZAKI, TAKASHI, SAIJO, YOSHIHIRO
Applicants: NIPPON ACCHAKUTANSHI SEIZO KABUSHIKI KAISHA
Application year: 1985
Main classification: H01R43
IPC codes: H01B13, H02G1, H01R43