Patent Application
20200094999
This application claims the benefit under 35 U.S.C. § 119(a) of European Patent Application No. 18196954.4, filed on Sep. 26, 2018, the entire contents of which are incorporated herein by reference.
The present invention relates to the field of mounting cable ties, for example when assembling cable harnesses. In cable harnesses, a plurality and possibly many cables are assembled and are affixed to each other via cable ties to be attached.
A cable tie mounting tool comprises an upstream and a downstream jaw having concave guidance path portions for the strap of a cable tie, a placing mechanism configured to place a cable tie portion along the common concave guidance path by pushing it strap-end-first along the common concave guidance path starting at the upstream end of the upstream jaw and pushing it in downstream direction, an insertion mechanism for feeding the cable tie strap end of the placed cable tie through the head of the placed cable tie, and a tightening mechanism for tightening the cable tie. Also provided is a length adjustment mechanism for adjusting the length of the common concave guidance path.
The terms “upstream” and “downstream” are relative to the movement direction of a cable tie strap along the guidance path. Downstream is the direction along which the cable tie strap moves when it is inserted, and upstream is the opposite direction from which the cable tie comes when inserted.
The placing mechanism may be configured and act such that when the cable tie is placed, its free strap end rests immediately opposite of and adjacent to the strap receiving opening in the cable tie head. The distance then may be below 5 mm or below 2 mm The insertion mechanism pushes the strap end finally through the strap head. Downstream of the head, the free end of the cable tie strap will be caught by some kind of tightening mechanism and can then also be cut-off after having been tightened.
The length adjustment mechanism is provided such that the inner circumference length of the loop formed by the closed jaws of the tool can selectively be shortened compared to a possible maximum length. This can be achieved by pushing path portions radially inward such that a long loop portion is more or less shortcut. “Radial” here refers to a direction in the loop plane towards or away from a point in the center region of the loop. A radial movement shall be a movement having a predominant radial component.
The guidance path for the cable tie needs not continuously be provided along the entire length of the cable tie strap. Cable tie straps have a certain rigidity and thus can reach across gaps in the path e.g. from one guidance path portion to another guidance path portion. This will be explained more in detail further down this specification. As far as guidance path lengths are considered, these lengths can include gaps amongst path portions, to be taken into account as they are bridged by a traveling cable tie strap.
Generally speaking, the cable ties as provided are usually straight and must be bent into loop form. Accordingly, the cable tie guidance path provided around the inner periphery of the loop formed by the closed jaws is oriented radially outward, and the guided cable tie strap is oriented radially inward and forced to bend into a loop shape by the concave shape of the various guidance path portions.
The length adjustment mechanism can automatically be operated and can, for a series of cable ties to be attached, be set once such that the inner circumferential length of the mentioned loop formed by the jaws is such that the strap end comes to rest immediately opposite of, and adjacent to, the opening in the strap head of the cable tie. Thus, the provision of the length adjustment mechanism makes the change of the jaws for the configuration to different cable tie lengths superfluous.
Both the length adjustment mechanism and the insertion mechanism may comprise at one of the jaws a pivotable path portion. Their pivot axis may be perpendicular to the plane of the opening confined by the closed jaws, so that pivoting around this pivot takes place in the plane of the opening area. Particularly, the arrangements may be such that the pivoting is radially inward into the opening or radially outward.
Generally speaking, both insertion and length adjustment shorten the length of the inner peripheral length of the loop of the cable tie strap. Shortening can be achieved by pushing guidance path portions radially inward so that a possible longer loop geometry is selectively shortcut.
A particular advantage is achieved when the pivotable path portions used for length adjustment and used for insertion are the same, configured to make the two movements for respective path shortenings as required. Then, only one movable part is required for accomplishing the two functions of path length adjustment and insertion of the cable tie end into the cable tie head. The drive of this portion is then configured to make the respective movements when and as required. Driving may be made by a controller, preferably a digital controller.
But different to what was just said, the pivotable path portions for insertion and for length adjustment may be different distinct path portions and may individually be driven as appropriate in space and time.
The jaws may be of concave shape, and likewise the pivotable path portions as well as the other path portions provided by the various components of the tool can be of concave shape. In cooperation, they form a concave guidance for the cable tie strap, forcing the strap into loop shape such that the strap end reaches back into the opening of the strap head. As already said, the guidance path may have gaps. It is not required that it supports the cable tie strap without interruptions. Likewise, it may have certain edges or portions of low radius of curvature. It needs not be circular and may have another appropriate contour.
Where the cable tie strap reaches back to the cable tie head, the guidance path portions may cross each other under a desired angle. Usually, insertion direction of the strap into the head is more or less perpendicular to the direction of the strap portion immediately formed at the head. Accordingly, likewise the guidance path portions will have, at the insertion point, a corresponding angle, i.e. substantially rectangular or corresponding to the insertion direction of the strap end into the strap head, possibly with some deviation from said direction that may be below ±20° or ±10°.
Preferably, the pivot of the pivotable path portion is provided at the upstream end of the pivotable path portion, so that the downstream end thereof is freely movable within its other constructive constraints around said pivot. By hinging the pivotable path portion at its upstream end, reactionary forces when pivoting the concerned path portion are reduced. Preferably, the pivotable path portion of the length adjustment mechanism is provided at the downstream jaw. This again reduces reactionary forces when using the pivotable path portion particularly for inserting the cable tie strap end into the cable tie head. It is preferred that the pivotable path portion of the length adjustment mechanism is pivotably attached to the upstream end of the downstream jaw. This minimizes the reactionary forces when reducing the loop circumference by pivoting the pivotable path portion.
The drive mechanism of the pivotable path portion is configured to drive individual steps of said pivotable path portions as required. Particularly, it may adjust, in a first step for reducing the peripheral length of the loop provided by the closed jaws, the length to a value corresponding to the strap length of a presently used cable tie. Then, when using the tool for actual cable tie mounting, this general setting may be maintained, and further circumference reducing steps may be driven for inserting the cable tie strap end into the cable tie head.
The first step for length adjustment may be an absolute step in the sense that it is selected in dependence of the cable tie length to be handled, whereas the second inserting step may be an incremental step for pushing the cable tie strap end through the cable tie head to an extent such that a tightening mechanism downstream of the cable tie head can catch the cable tie strap end for tightening it.
Again generally speaking, the guidance path portions of the upstream jaw and of the downstream jaw have different lengths. The length adjustment mechanism is preferably provided at the jaw having the longer of the two guidance path portions. This gives sufficient room for the pivotable path portion to provide for sufficient dimensional variation of the loop circumference for shortening/adjusting the guidance path length and for inserting the strap end into the head.
Looking at the jaw having the pivotable path portion, this jaw preferably also has a fixed path portion cooperating with the pivotable path portion. All these path portions can be held by a holder of concave contour. The holder itself must be concave because also the holder must reach around the items to be tied. Particularly, the holder may hold the pivot of the pivotable path portion and may hold the fixed path portion in fixed and well-defined manner in relation to the pivotable path portion.
Particularly, the pivot of the pivotable path portion may sit at the upstream end of the holder when it is all provided at the downstream jaw. The free—downstream—end of the pivotable path portion points to a fixed path portion and will guide the cable tie strap towards varying positions along the fixed guidance path depending on the pivoting position of the pivoting path portion. A variable gap may be provided between the downstream end of the pivotable path portion and the fixed path portion, depending on the pivot position of the pivotable path portion. Nevertheless, the fixed path portion is designed such that it securely catches the arriving free end of the cable tie strap and then guides it downstream.
One or more of the guidance path portions may have a U-shaped cross-sectional contour with a flat bottom for receiving the strap of the cable tie. The U-shaped contour may be shallow and have relatively short legs. Generally speaking, the length of the legs can be selected such that on the one hand side the cable tie strap is safely caught and guided and is prevented from escaping sideways, but is preferably kept small enough for avoiding unnecessary increase of frictional forces and other unwanted effects. The sidewalls of the guidance path portions profile may be relatively high where the guidance path has small radii of curvature because the likelihood of escaping is higher at such portions.
So far, a construction was described that is configured to independently handle guidance path length adjustment and the insertion of the cable tie strap end into the cable tie head. But for receiving similar effects also another approach can be considered, namely to have no particular length adjustment mechanism. Instead, an insertion mechanism is provided that can implement different step lengths for the insertion depending on the length of the cable tie to be mounted.
Assuming that the loop length of the guidance loop provided by the closed jaws does not change, it will remain the same both for long and for short cable ties. Then, layout must be made such that the longest cable ties to be handled must fit into the loop. Then, shorter cable ties will not fill out the loop. Further, since the cable tie head must be held at a predefined position, the cable tie strap end will come to rest at different positions along the loop, and accordingly, when the cable tie strap end is to be inserted into the cable tie head, different step lengths of the pivotable path portion for inducing the inserting effects are required. For shorter cable ties (having their ends resting remote from the head) a longer pivoting step is required, and vice versa. Thus, in these embodiments, there is no extra (initiating) path length adjustment required. But provisions must be made for obtaining the appropriate pivoting length when inserting the cable tie strap end into the cable tie head.
These provisions may again be implemented by an appropriate control. But likewise, some kind of self-adjusting mechanisms may be chosen, for example driving the pivotable path portion until a certain resisting force is encountered, or the like.
A method for automatically mounting a cable tie by a tool around items to be tied, comprises the following steps:
(1) adjusting the length of a common guidance path for the cable tie in the tool,
(2) opening two concave jaws of the tool, the jaws forming, when closed, said common guidance path for the cable tie,
(3) approaching the items to be tied and the opened jaws,
(4) closing the jaws such that the items to be tied are surrounded by the jaws,
(5) placing a cable tie along the common guidance path,
(6) feeding the cable tie end through the cable tie head
(7) tightening and possibly cutting the free end of the cable tie, and optionally
(8) repeating the steps (2) through (7) in the above sequence.
All steps may be executed automatically. Step (1) may be executed semi-automatically, for example by manually selecting a setting from a menu, the selected setting then being set automatically, or may be made manually by adjusting the common guidance path portion to the length of the cable ties to be used. Step (3) can be made automatically, e.g. by a robot holding and moving the tool, or manually by a worker working with the tool along a harness for attaching the required cable ties.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Reference numeral 10 symbolizes the items to be tied by a cable tie. For simplification it is drawn as a cylinder, but usually it is a bunch of cables, tubes and the like to be tied together. 11 is the upstream jaw with its upstream end llu and its downstream end 11d. Numerals 12, 13 and 14 constitute together the downstream jaw with its upstream end 12u and its downstream end 12d. Both are shown to be pivotable around their respective pivots 11p and 12p. Their pivoting movement is used for opening and closing the jaws, opening being such that the downstream end 11d of the upstream jaw 11 and the upstream end 12u of the downstream jaw 12, 13, 14 are remote from each other so that the items to be tied 10 can get into the opening defined by the two jaws.
The upstream jaw 11 defines and forms an upstream guidance path 99a. The downstream jaw 12, 13, 14 defines and forms a downstream guidance path 99b, 99c. The guidance path is for guiding the strap 62 of a cable tie 61-63.
A cable tie head with the opening therein indicated by the dashed channel 61a. The situation in
Support 15 symbolizes a support in the sense of a fixation point and may be seen as a part of the overall machine or machine body carrying the mentioned components. Particularly, the pivots 11p and 12p are attached to support 15. The support may consist of plural members fixedly or movably attached to each other.
The downstream jaw 12, 13, 14 may be formed by one or more holders 12, 12l, 12r.
Various operational states of the pivoting path portion 13, 99b will now be described with reference to
The pivotable path portion 13, 99b comprises a rail-like member 13b of concave shape bearing on its concave inner surface the actual guidance path portion 99b that is pivotable and has an upstream end 99bu and a downstream end 99bd. The pivot 13p is at the upstream end of the pivotable path portion 13, 99b and is also at the upstream end of the downstream jaw 12, 13, 14, as shown. At the distal ends (downstream end 11d of upstream jaw 11 and upstream end 12u of downstream jaw 12, 13, 14) the two path portions 99a of the upstream jaw 11 and 99b of the pivotable path portion 13, 99b are more or less contiguous, and a cable tie strap pushed along said path in downstream direction, i.e. from the upstream end flu of the upstream jaw 11 and then travelling in clockwise direction in
As also shown in
In
In
It is pointed out in this context that all the
But different from the shown embodiments, the downstream jaw may hold the shorter path portion and the upstream jaw may carry the longer path portion, and could then also carry the pivotable path portion, then again pivotably held at its upstream end.
Altogether, in
Movement of the pivotable path portion 13, 99b was such that the lever was again moved rightward as indicated by the direction of arrow F, and the downstream end 99bd thereof travelled downward along the of arrow G. Through this further pivoted position an even greater portion of the maximum available opening is shortcut, so that the guidance path length has again decrease compared to
In a first operational example, it is assumed that relatively long cable ties are to be mounted. A slightly reduced guidance path length corresponding to position P3 would be suitable for positioning the cable tie strap end right opposite of and adjacent to the opening in the cable tie head. It is further assumed, that position P5 would be the position sufficient for inserting the cable tie strap end into and through the cable tie head and into the reach of a tightening mechanism.
In operation, then, in a first step 53-1, the pivotable path portion is brought to position P3. Then, or before that, the tool can be brought to the mounting side and the jaws can be closed. Then, the cable tie is inserted into the guidance path. Once this is achieved, a movement 53-2 of the pivotable path portion towards position P5 follows for pushing the cable tie strap end 63 through the cable tie head 61 toward the reach of the tightening mechanism 64. Once this is done, the pivotable path portion retracts by movement 53-3. Then, the jaws are opened, the tool is displaced to a new mounting site, the jaws are closed and then the reversing operation between positions >>P5>>P3 is repeated by movements 53-4 and 53-5. The reversing movements 53-2 to 53-5 are relatively short since they must cover only the distance necessary for the cable tie end 63 to travel from the position immediately in front of the cable tie head opening 61a through said opening towards the reach of the tightening mechanism 64. This may be called work time tw of jaws, as indicated in
Further down in
So far, an operation method with distinct adjustment steps and inserting steps has been described. Variable is the first step for adjusting the guidance path length to the length of the mounted cable ties, whereas the various movements of the pivotable path portion 13, 99b thereafter, as indicated by 53-2 to 53-5, are the same because they must cover the same distance from upstream of the cable tie head opening 61a to downstream thereof into the reach of a tightening mechanism 64. Correspondingly,
The lower portion of
Altogether, the described tool may be configured for handling cable ties of variable length, for example with a minimum length of 90 mm or 100 mm or 110 mm, and/or with a maximum length of 220 mm or 200 mm or 180 mm The length of the inner circumference of the loop defined by the closed jaws and the pivotable path portion may thus be adjusted for handling said lengths. The length adjustment mechanism may be configured to reduce the guidance path length from its maximum to a length below 80% or below 70% or below 60% of the maximum length.
Features described in this specification shall be deemed combinable with each other also if their combination is not expressly mentioned, to the extent that this combination is technically feasible. Features described in a certain context, embodiment, figure or claim shall be deemed separable from this claim, context, figure or embodiment, to the extent that this is technically feasible, and shall be deemed combinable with other embodiments, contexts, figures or claims, to the extent that it is technically feasible. Descriptions of methods and method steps shall be deemed also as description of means for implementing the method or method step, and vice versa.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18196954.4 | Sep 2018 | EP | regional |
