The invention relates to a straightening apparatus for straightening cables that can be part of a cable processing machine. Such cable processing machines are used for the assembly of electrical cables. When assembling cables, cables can be cut to length and stripped and then the cable ends can be crimped. The cable processing machines can further comprise grommet stations in which the stripped cable ends are fitted with grommets before crimping.
The cables, such as insulated strands or solid conductors made of copper or steel, which are processed on a cable processing machine, are usually provided in drums, on rolls or as a bundle and are therefore more or less curved and provided with a twist after unrolling. Straight cables are important in order to be able to reliably carry out process steps such as stripping, crimping and possibly fitting with connector housings provided on the cable processing machine. In order to straighten the cables as straight as possible, they are usually pulled with the help of the drives in the cable processing machine through a straightening apparatus attached to the machine inlet.
A generically comparable straightening apparatus is known, for example, from EP 2 399 856 A1. The straightening apparatus has an upper and a lower roller group. The cable to be straightened is passed between the rollers of the two roller groups in a transport direction. The roller groups can be moved relative to one another to set the straightening parameters. Starting from an open position in a closing direction that is perpendicular to the direction of transport of the cable, the upper roller group is first displaced against the lower roller group into a closed position. In this closed position, the parallel rollers of the upper and lower roller group are on the cable and touch it. This process is also known and familiar to the person skilled in the art under the name “infeeding”. The distance between the rollers can be set manually using a rotary knob. An additional quick-release lever enables the straightening apparatus to be opened and closed quickly when the cable is removed and inserted between the rollers. Alternatively, the roller spacing can also be set automatically. For this purpose, the infeed mechanism for displacing the upper roller group against the lower roller group is provided with a motor drive, for example. However, this variant is technically complex and costly.
It is an object of the present invention to avoid the disadvantages of the known and in particular to provide an improved straightening apparatus of the type mentioned at the outset. According to the invention, this task is achieved by a straightening apparatus having the features described below.
The straightening apparatus for straightening cables comprises a first roller group having a plurality of rollers and a second roller group having a plurality of rollers opposite the first roller group, wherein the cable alternates between the rollers of the first roller group in a transport direction and the rollers of the second roller group. The straightening apparatus further comprises, for example, a manually operable or motor-driven infeed device with which the first roller group can be displaced against the second roller group. The fact that the straightening apparatus includes securing means for securing the first roller group in terms of position enables the roller spacing to be set precisely. The infeeding, i.e. the process in which the first roller group is brought from an open position to a closed position, can be carried out in an efficient manner.
Thanks to the infeed device, the first roller group, starting from the open position in the closing direction, which runs transversely and preferably at right angles to the transport direction, can be displaced against the second roller group for adjusting the distance between the rollers of the first and the second roller group. The open position is the position in which the rollers of the first and the second row of rollers are spaced apart so far that the cable can be inserted between the rollers. The closed position is the position after the end of the displacement movement; the infeeding process is complete. In the closed position, the rollers of the first and the second roller group touch the ideal cable in such a way that it is straight and not wavy.
The straightening apparatus can have a first roller support for the first roller group, to which the rollers of the first roller group are fastened in a freely rotatable manner, and a second roller support for the second roller group, to which the rollers of the second roller group are fastened in a freely rotatable manner. Furthermore, the straightening apparatus may have a frame, for example in the form of a base plate, for carrying the first and the second roller support, wherein the first roller support is displaceably mounted in the frame in the closing direction.
In a preferred embodiment, the straightening apparatus for forming the securing means may comprise a backstop which blocks a backward movement of the first roller group against the closing direction during the infeed process. Thanks to the backstop, the straightening apparatus can be operated reliably, ergonomically and efficiently with regard to the infeed process.
For this purpose, discrete backstops such as backstops based on a ratchet mechanism can be provided. Such a ratchet mechanism can comprise, for example, a toothing and a pawl interacting with it. With the ratchet mechanism, however, pilgering movements would be possible. It is therefore advantageous that the infeed device of the straightening apparatus comprises a stepless backstop. Stepless backstops have the advantage that they can prevent practically all unwanted back movements.
The aforementioned backstop can be configured as a backstop with a positive fit. The backstop can also be configured as a non-positive backstop. In addition to mechanical backstops, other backstops are also conceivable. The backstop could be a hydraulic cylinder; if the roller support wants to move back, the outflow of hydraulic oil from the hydraulic cylinder is prevented by check valves and thus the backstop is effective.
It is also advantageous if the first roller support is supported on the frame by a spring element, in particular a helical compression spring, which acts on the first roller support with a spring force against the closing direction. Safe functioning of the backstop can thus easily be guaranteed.
The backstop can comprise a clamping body and in particular a clamping roller, wherein the clamping body or the clamping roller is received in a wedge gap. The wedge gap can be a receptacle for the clamping body that tapers in relation to the closing direction. Due to the wedge effect, the clamping body pressed into the wedge gap can reliably block a return movement of the first roller support.
The backstop can comprise a spring for generating a pretension for the clamping body, in particular the clamping roller. The spring-loaded clamping body is pressed continuously into the wedge gap, thus ensuring that the backstop functions reliably.
The first roller support can have a wedge-shaped contact surface which, together with a stationary counter surface, forms the wedge gap. The stationary counter surface can be formed, for example, by a guide surface assigned to the frame, along which the first roller support can be guided during the closing process.
Alternative backstops could comprise two wedges, wherein the wedges have oppositely directed, oblique wedge surfaces which, if a return movement would take place, are pressed against one another and thus prevent the return movement. Other alternative backstops could include eccentric bodies.
The straightening apparatus can have a manually actuated infeed device with an operating element that can be moved linearly in the closing direction, in particular in the form of a button, by means of which the first roller support or the first roller group can be displaced in the closing direction, for example by pressing the operating element. Such a straightening apparatus is characterized by simple handling and good ergonomics. The operating element simply has to be pressed for infeeding. A quick release lever for quick closing is also not required.
A driver can be connected to the operating element for advancing the first roller support. The driver can connect to a shaft of the operating element or be formed by the shaft itself. The shaft is an elongated component that extends in the closing direction. The driver or the shaft can be slidably mounted in the frame and can be moved in the closing direction (and possibly in the opposite direction). The driver bumps against the first roller support when it is pressed by pressing the button-like operating element or when it is moved in the closing direction in some other way and thus displaces the first roller support in the closing direction. A straightening apparatus with a motor-driven infeed device can also have such a driver.
The backstop is preferably configured as a releasable backstop. For this purpose, an unlocking element may be provided to release the locking effect of the backstop.
An unlocking element for releasing the locking effect can be arranged on the driver or connected to the driver. The driver with the unlocking element is configured in such a way that during a return movement, that is to say during a movement in the opposite direction to the closing direction, the unlocking element can be brought into abutment with the clamping body. The unlocking element may be a nose-like projection protruding from the driver or the shaft. To release the locking effect, the unlocking element may push the clamping body away, so that the clamping body no longer contacts the wedge-shaped contact surface of the wedge gap, that is to say there is no longer any clamping.
The locking effect can be released by pulling the button-like operating element. This solution is characterized by simple handling. Other means could also be used to release the locking effect. For example, it could also be advantageous not to use the aforementioned operating element for closing the straightening apparatus for the opening process. If separate means for releasing the locking effect are used, incorrect manipulations on the operating element, which result in an unintentional release of the locking effect, can be excluded.
The straightening apparatus does not necessarily have to have a manually operated infeed device. For certain areas of application, it may be advantageous if the straightening apparatus has a drivable infeed device with a linear direct drive, a pneumatic cylinder or a hydraulic cylinder for moving the first roller support in the closing direction. Such infeed devices may be easily controlled and operated automatically or semi-automatically.
In a further embodiment, the straightening apparatus can have a contact roller for fixing the closed position, wherein the contact roller is arranged downstream of the first roller group with respect to the transport direction, and wherein the cable may be pressed between the contact roller and a counter roller assigned to the second roller group and opposite the contact roller.
Alternatively, the straightening apparatus for fixing the closed position can have at least one and preferably a plurality of contact fingers, which are preferably displaceable to a limited extent in the closing direction, wherein the at least one contact finger is assigned to one of the roller groups and in particular to the first roller group. In this case, the contact finger may in each case be arranged opposite a roller of the other roller group, in particular the second roller group, in such a way that the cable can be pressed between the respective contact finger and the opposite roller. The contact fingers can be configured such that they can be brought into a rest position by moving in the opposite direction to the closing direction after the closing position has been determined, so that they no longer act on the cable.
To further generate the straightening effect of the cable after the infeed process has ended, it is advantageous if the second roller support is rotatably mounted on the frame about a swivel axis and that the straightening apparatus has a swiveling device, for example manually operable or motor-driven, with which to set the angle of attack between the rollers of the first and the second roller group; the second roller group is preferably swivelable from a neutral position into an active position.
The second roller support can particularly preferably be rotatably mounted on the frame such that, by swiveling the second roller support, the rollers on the input side act more strongly on the cable than the rollers on the output side. The swiveling device can, for example, be a device as it is known per se from EP 2 399 856.
In one embodiment, a link guide for the movement of the first roller support and/or the second roller support can be provided.
A linearly movable thrust element can be provided for the link guide, by means of which both the first roller support and the second roller support can be moved. The thrust element can be configured to be operated manually or to be driven by a motor. In this embodiment, the two straightening parameters (roller spacing, angle of attack) can be set in a single common work step or actuation movement.
The straightening apparatus can have a manually operable thrust element with a hand lever, preferably movable back and forth in the transport direction.
On the thrust element, an infeed link guide for displacing the first roller support in the closing direction and an opening link guide for releasing the locking effect and for returning the first roller support can be arranged. In this case, a first, spring-loaded control body can interact with the infeed link guide and the opening link control. A swiveling link guide for swiveling the second roller support can be arranged on the thrust element. A second, spring-loaded control body can interact with the swiveling link guide.
The swiveling link guide can be formed by a stepped control track with preferably a plurality of receptacles for the control body for setting discrete angles of attack. This enables the attack angle to be set particularly quickly. Such a swiveling link guide could also be used in conventional straightening devices, i.e. in straightening apparatuses without a backstop or other securing means for securing the position of the first roller group shifted by means of the infeed device.
Additional advantages and individual features of the invention are derived from the following description of an exemplary embodiment and from the drawings. The drawings show the following:
The upper rollers 20.1 to 20.7 and the lower rollers 21.1 to 21.6 run parallel to each other and are each on horizontal roller lines. The cable (not shown in
The basic arrangement and orientation of the roller groups 2 and 3 shown here relate to embodiments of the straightening apparatus 1 according to the invention. Of course, other arrangements and orientations of the roller groups 2 and 3 are also conceivable. For example, the two roller groups 2 and 3 could also be arranged side by side; in this case, the closing direction s would run on a horizontal plane.
The straightening apparatus 1 described in detail below may be used in a cable processing machine (not shown) for the assembly of cables. The cable processing machine can process electrical cables, for example insulated strands or insulated solid conductors made of copper or steel. The cables to be processed are provided in drums on rolls or as a bundle. The cables fed from drums, rolls or bundles to the cable processing machine are more or less curved and have a twist. The cable must therefore be straightened, for which the straightening apparatus 1 mentioned at the beginning is used.
The cable processing machine can be designed, for example, as a swivel machine that has a swivel unit with a cable gripper. To feed the cable ends to processing stations, such as a grommet station and a crimping station, the swivel unit must be rotated about a vertical axis. A cutting and stripping station is usually arranged on the machine longitudinal axis of the cable processing machine. The cable processing machine then comprises an infeed unit with, for example, a cable conveyor configured as a belt conveyor, which brings the cables to the swivel unit in the transport direction along the machine longitudinal axis. The straightening apparatus 1 is arranged in the cable processing machine upstream of the belt conveyor on the longitudinal axis of the machine. When the cable is fed to the swivel unit, the cable is pulled through the straightening device 1 for straightening the cable 4.
The rollers 20.1 to 20.7 of the first or upper roller group 2 are freely rotatably attached to a first roller support 6. The rollers 21.1 to 21.6 of the lower or second roller group 3 are freely rotatably attached to a second roller support 7. The straightening apparatus further comprises a frame 8 in the form of a base plate for carrying the first and second roller supports 6 and 7. The roller supports 6, 7 are configured plate-like in the present case.
The first roller support 6 with the upper rollers 20.1 to 20.7 is displaceably mounted in the frame 8 in the closing direction s. The second roller support 7 with the lower rollers 21.1 to 21.6 is rotatably mounted in the frame 8 with respect to a horizontal swivel axis indicated by 24 and runs at right angles to the transport direction. The basic structure of the straightening apparatus 1 is similar to the straightening apparatus known from EP 2 399 856 A1; moving the roller support 6 with the upper rollers 20.1 to 20.7 for the infeed process takes place by means of a novel infeed device 5.
The infeed device 5 is configured to be manually operable and comprises an operating element 16 that can be moved linearly in the closing direction s. The first roller support 6 is supported on the frame 8 by a spring element 10 in the form of a helical compression spring, which acts on the first roller support 6 with a spring force against the closing direction s. By pressing the operating element 16, the first roller support 6 can be displaced downward with the upper rollers 20.1 to 20.7. The operating element 16 is pressed down until the rollers 20.1 to 20.7 and 21.1 to 21.6 touch the cable.
For the infeed, the operating element 16 only has to be pressed, which results in particularly simple and ergonomic handling. The second roller support 7 with the lower roller group 3 is not moved during the infeed process. For this purpose, the lower roller group 3 is held by a machine control via a pneumatic valve and a pneumatic cylinder 33 in a position parallel to the upper roller group 2, which corresponds to a neutral position.
In the present example, the operating element 16 has the shape of a button. Of course, other shapes for the operating element 16 would also be conceivable. For example, the operating element 16 could have a bow-like handle.
In order to secure the position of the upper roller group 2 displaced in the closing direction s by the infeed device 5, the straightening apparatus 1 comprises a backstop (9, see
A freely rotatable contact roller 19 is also arranged on the first roller support 6. The contact roller 19 is arranged on the output side following the upper roller group 2 with respect to the transport direction x and serves to fix the closed position. A counter roller 22 is provided on the second roller support 7 on the side opposite the contact roller 19. If, starting from the open position (
As can be seen from
The operator, who presses the operating element 16 downwards, feels an abruptly increasing counter pressure as soon as the cable 4 is pressed between the contact roller 19 and counter roller 22. The operator is thus informed that the infeed process has been completed (
A guide roller 37 is arranged at the front end of the first roller support 6 on the input side. The guide roller 37 has, compared to the rollers 20.1 to 20.7, a larger roller diameter to straighten the cable. The guide roller 37 is, compared to the rollers 20.1 to 20.7, vertically offset slightly downward, so that the guide roller 37, when the straightening apparatus 1 is in the closed position, is positioned below the cable. The guide roller 37 serves to facilitate the insertion of the cable 4 in the open straightening apparatus. The guide roller 37 makes it possible, for example, for the cable 4 to be tensioned by hand before and while the straightening apparatus 1 is closed, so that it can easily be ensured that the cable comes to rest when closing between all the rollers 20.1 to 20.7 and 21.1 to 21.6.
The backstop already mentioned can be seen in
Further structural details of the straightening apparatus 1 can be seen in
After the infeed process has ended, the second roller support 7 is swiveled about the swivel axis 24 into an active position in order to produce a sufficient straightening effect, so that the rollers 20.1, 21.1 on the input side act more strongly on the cable 4 than the rollers 20.7, 21.6 on the output side. For this purpose, the front side of the second roller support 7 is pulled upwards by means of a pneumatic cylinder 33, which is indicated in
In order to prevent the cable 4 from being crimped by the user when the cable is touched by the contact roller and the counter roller during the infeed process, the straightening apparatus 1 can have a device for limiting the force between the operating element 16 and the counter roller 22, for example in that the operating element 16 is at least indirectly connected to the counter roller 22 via a spring (not shown) and the stroke of the operating element 16 is limited by a mechanical stop.
In order to activate the straightening apparatus 1, the machine control (not shown) brings the lower roller group 3 into the active position, either after pressing a special button or automatically within a program sequence, in that the pneumatic cylinder 33 moves the lower roller group 3 to the upper roller group 2 on the input side. The restoration of the original starting position of the straightening apparatus 1 could also be carried out by pressing a button or started automatically within a program sequence. The key or the program sequence could actuate a pneumatic valve or a switch of the machine control, whereupon the lower roller group 3 is moved back via the pneumatic cylinder 33 into the position parallel to the first roller group 2. The machine control could also be configured in such a way that the activation of the pneumatic cylinder 33 for swiveling the lower roller group 3 back from the active position into the parallel neutral position could be triggered by pulling or possibly pressing the button-shaped operating element 16 again.
From
The swivel axis 24 could also assume other positions. For example, the swivel axis 24 could be coaxial with the axis of rotation of the counter roller 22. Furthermore, it would be conceivable to arrange the swivel axis 24 or the rollers 19 and 22 in the straightening apparatus in such a way that when the lower roller group 3 is swiveled they move towards one another and thus cause a slight squeezing effect on the cable. Squeezing can be advantageous for straightening cables with comparatively hard insulation. Such cables can be processed better if they are additionally crimped in diameter during or after straightening. If for this purpose the swivel axis 24, instead of to the left as in the exemplary embodiments shown in
It can be seen from
As can be seen from
The contact fingers 23 are pushed upwards after the closing position has been set, so that they are sufficiently far from the cable 4 and can no longer act on the cable, even if there is an active position created by swiveling. For this purpose, a carrier plate, which carries the contact fingers 23, has elongated holes 36, so that the contact fingers 23 or the carrier plate is or are mounted on the first roller support 6 such that they can be displaced in the closing direction to a limited extent.
The straightening apparatus 1 has a thrust element 25 which can be moved linearly in the transport direction x and via which the first roller support 6 with the upper rollers 20.1 to 20.7 and the second roller support 7 with the lower rollers 21.1 to 21.6 can be moved. In the present case, the thrust element 25 can be actuated manually via a hand lever 26. Instead of the hand lever 26, with which the thrust element 25 can be moved back and forth manually, the thrust element 25 could also be connected to a drive for moving the thrust element 25.
On the thrust element 25, an infeed link guide 27 for displacing the first roller support 6 in the closing direction s is arranged. Furthermore, an opening link guide 28 for releasing the locking effect and for returning the first roller support 6 is arranged on the thrust element 25. The link control comprises a control body, designated by 30, which interacts with the infeed link guide 27 and the opening link guide 28. The control body 30 is supported on the first roller support 6 via a spring 42.
A swivel link guide 29 for swiveling the second roller support 7 is arranged on the thrust element 25, wherein a spring-loaded control body, designated by 31, cooperates with the swivel link guide 29. The spring for generating the spring load on the control body 31 is designated by 43. The spring 43 supports the control body 31 upwards against the frame 8 of the straightening apparatus 1. The control body 31 is connected to the second roller support 7 via a lever 44.
The swiveling link guide 29 can be formed by a continuously rising control path or curve. It can be advantageous if the swiveling link guide 29 is formed by a stepped control track with a plurality of receptacles 32 for the control body 31. Such a link guide 29 with a stepped control path for setting discrete angles of attack is shown in the exemplary embodiment according to
The straightening apparatus 1 has the thrust element 25 with a hand lever 26 and the link guides 27, 28, 29. The thrust element 25 can be moved back and forth with the hand lever 26 relative to the frame 8. The link guide 27 controls the infeed process via the control body 30 designed as a roller, in which the upper roller group 2 is displaced downwards against the lower roller group 3. To set the closed position, this straightening apparatus 1 also has a contact roller 19 and a counter roller 22 opposite it. Alternatively, one or more contact fingers 23 could also be used. The link guide 29 controls the swiveling process via the control body 30 designed as a roller, in which the setting angle α of the lower roller group 3 is set.
The mode of action of the link guide for infeed and swiveling is as follows: The starting point is the open position shown in
As already mentioned above, a good straightening effect is achieved if the rollers 20.1, 21.1, 20.2, 21.2, . . . lie at the entrance in such a way that the cable 4 has to move between the rollers in a wave-like manner such that the cable 4 is curved on every subsequent roller in decreasing intensity. If the thrust element 25 is now pushed further to the left, the spring 42 can relax and the spring (10) (not shown here) with which the first roller support 6 is supported on the frame 8 presses the roller group 2 into the backstop 9. If the thrust element 25 and thus the swivel link guide 29 is pushed further to the left, as shown in
If the thrust element 25 is moved in the opposite direction, that is to the right back to the starting point, the straightening apparatus 1 is accordingly brought back into its open state or open position. The swivel link guide 29 initially sets the lower roller group 3 back into the parallel neutral position via control body 31. The control body 30 moves along the opening link guide 28 and releases the backstop 9, whereupon the upper roller group 2 can be moved into the open position.
It would also be possible, instead of the linearly movable thrust element 25, to also control the two control bodies, for example with cam disks that can be driven in rotation.
A tension spring could also be used instead of the lever 44, so that the angle of attack of the lower roller group 3 is influenced indirectly via the corresponding spring force.
The opposing contact roller 19 and counter roller 22 could also be positioned further toward the swivel axis 24 in such a way that they move towards each other when the upper roller group 2 is infeeding. This achieves a crimping effect that corresponds to that of a so-called clamping roller.
In alternative versions of the straightening apparatus 1, it would be conceivable not to provide a fixed swivel axis 24. In order to enable the user to fine-tune the distance between the two roller groups 2, 3, the swivel axis 24 can be displaced vertically, for example, using an adjusting screw or an eccentric. A device could also be attached to the straightening apparatus 1, which enables a displacement between the frame 8 and the roller group 2.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
Number | Date | Country | Kind |
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19204346.1 | Oct 2019 | EP | regional |