Improved bundling tool for waste-free bundling of material

Abstract

This disclosure relates to a waste-free strapping tool for binding articles using unbroken strips, comprising: a clamping unit for guiding an end segment of the unbroken strip; a locking element feeding unit for providing a locking element; a push-pull unit for advancing the end segment along a path through the locking element and along the clamping unit, around the bound article and back into the locking element, and for subsequently pulling back the end segment; a sensor unit and a cutting unit; and a control unit arranged, in a normal operating mode, for the push-pull unit to preset a greater advance speed for a first path portion of the path during pushing than a second path portion following the first path portion, the second path portion including a portion of the path extending back into the locking element, thereby providing an improved waste-free strapping tool for binding articles, particularly a more reliable, faster, and easier-to-operate strapping tool.

Description

Technical Field

[0001] This disclosure relates to a waste-free strapping tool for binding materials / bound articles using an endless strip or strip, the strapping tool comprising: a replaceable clamping unit for guiding an end segment of the unbroken strip around the bound article; a locking feeder unit for providing a locking element for the unbroken strip; and a push-pull unit for advancing the end segment of the unbroken strip around the bound article and back into the provided locking element by means of a motor when the bound article is clamped by the clamping unit (i.e., when the unbroken strip is used as intended), and for subsequently pulling back the end segment of the unbroken strip to tighten the unbroken strip around the bound article; a sensor unit for detecting that the end segment is pushed back into the locking element; and a cutting unit for separating the end segment arranged around the bound article from the remaining portion of the unbroken strip retained in the strapping tool. Background Technology

[0002] In known waste-free strapping methods for bundling items, a rolled-up strip or band, propelled by a motor along a path through a locking element, is advanced around the item being strapped via a clamping unit, then returns to pass through the locking element again to form a loop around the item. Because the length of the strip used is not specific to the maximum diameter of the object being strapped, such a strip is also called a non-breaking strip (a continuous strip). A sensor unit detects when the strip, i.e., its end or end segment, is fed back into the locking element. Then, in response to a signal from the sensor unit, the control unit reverses the direction of the motor's operation, thereby tightening the strip around the item being strapped. Finally, the segment of the strip that has passed through the locking element and surrounded the item, i.e., the end segment, separates from the remaining portion of the strip. The remaining strip is retained in the corresponding strapping tool and can be fully utilized for the next strapping or binding operation. Because it does not require cutting off the loose ends of the straps, compared to the use of cable ties with a predetermined strap length, this type of bundling or binding is called waste-free bundling or binding.

[0003] By using clamping units with clamps / grippers of different sizes, the binding can be adapted to the different diameters of the items being bound. For example, the binding tool can be equipped with clamping units, each with clamps designed to have a maximum diameter of 30 mm, 50 mm, 80 mm, or 100 mm.

[0004] Because the tying or binding is performed at the highest possible speed, the end or end segment of the strip impacts the sensor unit at full speed. Since the control unit needs time to reverse the motor's direction of travel, the strip is pushed further than actually needed when passing the locking element. In this situation, the clamping jaws closing around the bundled item, and the entire system, must reliably guide the strip along the path to prevent lateral derailment. This lateral derailment is common but less likely to cause error messages and tying or binding failures. Summary of the Invention

[0005] The resulting task is to provide an improved strapping tool for waste-free strapping of items, and in particular, to provide a more reliable, faster, and easier-to-operate strapping tool.

[0006] This task is addressed through the subject of an independent technical solution. Advantageous embodiments are derived from dependent technical solutions, specifications, and drawings.

[0007] One aspect relates to a strapping tool that uses non-cut strips or bands to strap items without waste. Non-cut strips can be understood as strips individually cut to a certain length for each strapping process; for example, the strips are arranged in rolls and supplied from a storage unit to the strapping tool. When used as intended, the non-cut strips may have serrated portions formed on their outer sides pointing away from the strapping material.

[0008] The strapping tool has a replaceable clamping unit for guiding the end segment of the unbroken strip around the material to be strapped, and around the bundled item. The clamping unit can be a replaceable modular unit, particularly requiring no tools or only a single tool, such as a screwdriver or hex wrench. "Replaceable" specifically means that the clamping unit is designed to be replaced by the end user. The clamping unit may include at least one clamping jaw, preferably two, which are movably arranged relative to the remainder of the clamping unit and / or the remainder of the strapping tool, and close around the binding material as intended for guiding around the binding material. The strapping tool also has a locking element feeding unit for providing a locking element to the unbroken strip, separate from the strip. The locking element may have two through holes, specifically designed to engage the unbroken strip on its toothed outer side. Such a locking element may also be referred to as a sealing element or sealing head.

[0009] The strapping tool also includes a push-pull unit, which, on the one hand, uses a motor to advance the end section of the unbreakable strip along the path through the locking element provided by the locking element feed unit (the bundled item is held by the clamping unit and thus surrounds the bundled item during intended use), back into the provided locking element; on the other hand, it is used to subsequently pull back the end section of the unbreakable strip (and thus bind the bundled item with the unbreakable strip). To detect that the end section has been pushed back into the locking element, the strapping tool has a sensor unit. The sensor unit may have a mechanical stop element (such as a switch lever) that, upon a second passage through the locking element, for example after passing through a second opening in the locking element, the end of the unbreakable strip advancing along the path impacts the mechanical stop element, thereby triggering a sensor signal. Furthermore, the strapping tool also includes a cutting unit for separating the end section of the unbreakable strip arranged around the bundled item from the remaining section of the unbreakable strip retained at the bundled item. The control unit of the strapping tool can be designed to control different units of the strapping tool such that: first, the clamping unit closes (when used as intended around the bundled items); then, the unbreakable strip is advanced by means of a push-pull unit until the sensor unit provides a sensor signal; then, the motor's running direction is reversed to tighten the unbreakable strip until, for example, a predetermined tightening force is reached. Finally, the control unit can trigger the cutting of the unbreakable strip, thereby separating the end section arranged around the strapping tool from the remaining section of the unbreakable strip retained at the strapping tool by a cutting unit.

[0010] In normal operating mode, the control unit is designed to specify or set a higher advance speed for the end segment of the path during the push-pull unit's first path portion than for the second path portion following the first path portion. The first path portion has a first length, and the second path portion has a second length. The second path portion includes a portion of the path extending back into the locking element. Therefore, on this portion of the path where the end segment must re-enter the locking element and be detected by the sensor unit, the speed of the unbroken strip is slower than on the previous portion of the path, where the end segment is only initially guided through the locking element and / or along the clamping unit. The first and / or second lengths can be stored in the control unit, and can be determined particularly in the calibration operating mode described further below. The lengths of the various portions of the path can be stored or specified as spatial and / or temporal lengths, which can be mathematically converted to each other by the corresponding advance speed.

[0011] The advantage of this is that the higher speed of the non-breaking strip in the first path section keeps the binding / tying duration low, while the lower speed of the non-breaking strip in the second path section substantially improves the reliability of binding / tying. Therefore, the first path section should be chosen to be as large as possible, while the second path section should be chosen to be as small as possible. For example, the first path section can occupy the majority of the entire path, i.e., more than 50%, particularly more than 65%, and preferably more than 80%. Furthermore, the lower speed in the second path section gives the control unit more time to decelerate and switch the push-pull unit motors, reducing the likelihood of the non-breaking strip exceeding the set position. Therefore, time is saved again during the pull-back of the non-breaking strip, and the binding duration extended due to the slower advance in the second path section is further shortened. In addition, overall wear is reduced, particularly wear on the sensor unit.

[0012] In another embodiment, the provided control unit is designed to preset a lower advance speed for the end segment of the first path portion than in the normal operating mode in a calibration operation mode for automatically calibrating the strapping tool. Specifically, the advance speed for the second path portion in the normal operating mode is preset to the advance speed of the push-pull unit for the first path portion in the calibration operation mode. The equivalent distance for the first path portion is determined, and the length of the first path portion in the calibration operation mode is also determined. Alternatively or additionally, the equivalent distance of the second path distance segment can also be determined, thereby determining the length of the second path distance segment. Here, the equivalent distance can be considered as any amount from which the length of the first path portion can be determined based on predetermined design-related boundary conditions. An example is the encoder or motor step count of the (stepping) motor of the push-pull unit described below, which, via the corresponding geometry in the push-pull unit, allows the calculation of the distance covered by the end segment in the corresponding path portion. For example, one encoder or motor step count may correspond to a distance of 3 millimeters. Therefore, in calibration operation mode, a lower push speed or feed rate can maintain the corresponding equivalent value with higher accuracy, which is why a lower push speed is advantageous in calibration operation mode. However, the path length equivalent value can also include or be the path length itself, for example, detected by a separate sensor element, such as based on the toothed portion of a non-broken strip.

[0013] The advantage of this is that the length of the first and / or second path sections can automatically adapt to the size of the clamping unit, allowing the use of a stored table to determine, for example, the size of the clamping unit and the corresponding length of the first and / or second path sections. Through automatic adjustment, setup speed and reliability in the relevant application can be dynamically optimized with minimal effort.

[0014] Before the first path section, there may be an initial path section in which the increased advance speed is always (i.e., in both normal and calibration operating modes) specified for the end section. This is advantageous, for example, if it is known at the factory that a predetermined minimum size of the clamping element diameter for the strapping tool, such as 30 mm, will not fall below the size of the clamping unit available for the strapping tool, and is stored accordingly in the control unit. The length of the initial path section is then preferably consistent with the length of the first path section stored for the clamping unit with the specified minimum size. This increases the speed of the strapping tool in calibration operating mode.

[0015] In another embodiment, the provided control unit is designed to determine the equivalent distance in a calibration operation mode by calculating the number of motor steps (specifically designed as a stepper motor) of the push-pull unit during the advance end section. Specifically, the motor can also be designed as a DC motor, such as a brushless DC motor. The motor may be equipped with a gearbox. Whether designed as a stepper motor or simply a (brushless) DC motor, step control can be achieved via a corresponding encoder. These steps can then be determined in both cases.

[0016] The advantage of this is that the corresponding path segment and / or path length can be detected without additional sensors. The control unit only needs to calculate the number of motor / encoder steps until it receives a sensor signal from the sensor unit to detect that the end segment has been pushed back into the locking element. Then, in normal operating mode, for the first set of motor steps corresponding to the first path segment, and therefore usually the main part of the total number of motor steps (see the definition of "main part" above), a larger advance speed is set, while for the second set of motor steps corresponding to the second path segment, a smaller advance speed is set. Since neither new sensor technology nor higher computing power than before is required, the aforementioned advantages of faster and more reliable strapping can be achieved in a particularly simple way.

[0017] In another embodiment, the provided control unit is designed to automatically deactivate the calibration operation mode after the equivalent distance has been determined once or multiple times, particularly after the equivalent distance has been determined twice. This has the advantage of simplifying operation, while having proven to determine the equivalent distance and therefore the length of the corresponding distance segment with sufficient reliability and accuracy, especially when the equivalent distance is calibrated twice.

[0018] In another embodiment, the control unit is designed to automatically activate the calibration operation mode after the strapping tool is turned on, specifically after the control unit is powered on. Since it has been found that the clamping unit is typically replaced when the strapping tool is off, this ensures that changes in the size of the clamping unit can be detected by the strapping tool, achieving the aforementioned advantages with high daily reliability.

[0019] In another embodiment, the control unit is configured such that, in normal operating mode, the detection sensor unit detects the (particularly relative) equivalent time when the end segment is pushed back into the locking element, and checks whether the detected equivalent time corresponds to the equivalent time stored for the advancement of the push-pull unit. Only when the two equivalent times correspond (sufficiently accurately) does the specified and therefore unchanged normal operating mode continue. As a relative equivalent time, the equivalent time can be predetermined, for example, relative to the amount sensed at the start of the push. The equivalent time can include one or more internal timestamps and / or time periods and / or one or more absolute time points, such as the trigger time (absolute or relative) for the strapping tool to perform strapping and the detection time when the end segment is pushed back into the locking element. The stored equivalent time, such as the duration from the start of the push to the detection time (trigger sensor signal), can also be determined independently of the calibration operating mode: for example, a standard value or default value can be initially stored and then adjusted in normal operating mode, particularly gradually. Calibration is then performed during normal operating mode, which can be referred to accordingly as a self-calibrating normal operating mode.

[0020] Therefore, the control unit checks whether the sensor unit detects that the end has been pushed back into the locking element at the expected time, based on the stored path portion, i.e., the stored clamping unit size and / or the resulting length of the first and / or second path portions. This automatically checks whether the settings used for the first and / or second path portions are (still) correct. Thus, improved strapping reliability is achieved.

[0021] Equivalent time can also be or include equivalent distance. For example, in normal operating mode, multiple motor steps used to advance the end section along the path can be counted and compared with the number of motor steps stored for the installed clamping unit (e.g., detected in calibration operating mode), thereby checking whether the path portion or path portion length currently specified for normal operating mode is still correct, and whether to use it further accordingly. Accordingly, the control unit can be configured to determine the equivalent time by calculating the number of motor steps (specifically designed as stepper motors) of the push-pull unit during the advancement of the end section. This further improves reliability and binding safety.

[0022] In another embodiment, the control unit is configured to activate a calibration mode and / or check whether the detected equivalent time is greater than or less than the stored equivalent time when the recorded equivalent times deviate from each other (particularly significantly and / or frequently enough, e.g., at least twice). Then, if the detected equivalent time is larger, the first path portion with the larger advance speed of the end segment is increased; conversely, if the detected equivalent time is smaller, the first path portion with the larger advance speed of the end segment is decreased. The decrease or increase of the first path portion can be proportional to the magnitude of the deviation between the two equivalent times. This means that the advance speed can be adjusted according to changes in the size of the clamping unit in a very short time.

[0023] This is based on the understanding that when the size of the clamping unit decreases, the sensor unit detects the end segment earlier than expected, while when the size of the clamping unit increases, the sensor unit detects the end segment later than expected. Specifically, gradually expanding or shrinking the first path portion, for example from one binding process to another, results in adjusting the advance speed along the path, thereby achieving the aforementioned optimization: performing the fastest binding at the highest possible advance speed in the longest possible first path portion before the end segment's path ends, and performing the safest binding at the lowest possible advance speed in the shortest possible second path portion. Therefore, the aforementioned advantages are achieved particularly effectively and reliably here.

[0024] In another embodiment, the replaceable clamp unit is or comprises a fully mechanical clamp unit. Therefore, the replaceable clamp unit specifically lacks electrical operating elements and electrical and / or optical interfaces to the remainder of the strapping tool. This reduces overall complexity, while the aforementioned advantages are reliably achieved through the teachings described herein.

[0025] Another aspect relates to a strapping tool system, comprising a strapping tool according to one of the embodiments and at least two, preferably three or four different clamping units, preferably clamping units of different sizes. Here, the size of the clamping unit indicates the corresponding maximum strapping diameter for the items to be strapped / bundled. For example, the size of the clamping unit can cover a range between 25 mm and 120 mm, such as being or including sizes of 30 mm and / or 50 mm and / or 80 mm and / or 100 mm. This has the advantage of allowing for quick and easy replacement of different clamping units in practical work, while always achieving optimal strapping speed and reliability. In particular, it eliminates the need for specializedly qualified and authorized operators to perform changes to the strapping tool, as is typically the case.

[0026] Another aspect relates to a method for automatically calibrating a strapping tool configured to perform waste-free strapping of items using a non-breaking strip. One step involves advancing the end segment of the non-breaking strip along a path through a locking element and along the clamping unit of the strapping tool using a feed motor, returning it to the locking element, and specifically, also returning through the locking element. In this case, the end segment can already be advanced around the strapping element, i.e., advanced in the intended use. Therefore, the items can already be strapped during calibration. However, it can also be performed without strapped items, as a test or calibration run, which saves subsequent time. A subsequent process step is to detect that the end segment advanced into the locking element has reached the cut length or end position.

[0027] Another step is to determine, for example, read out, the number of encoder or motor steps required to advance the end segment to the end position. For example, the number of encoder or motor steps can be read out later or counted during advancement. Then, based on the number of encoder steps, a first advance speed for the encoder steps, corresponding to the first path portion of the path, is specified for future advancement. Therefore, advancement on the first path portion is performed at the first advance speed for future advancement following the current advancement where the number of encoder steps has been determined. Furthermore, a second advance speed lower than the first advance speed is specified for the encoder steps, which follow the encoder steps in the first path portion as the end segment is advanced along the path, and correspond to the second path portion of the path. Therefore, in the case of future advancement, advancement on the second path portion is performed at the lower second advance speed, which then serves as the current advancement where the number of encoder steps has been determined.

[0028] Another aspect relates to a method for waste-free bundling of articles using unbroken strips. One method step involves advancing an end segment of the unbroken strip along a path passing through a locking element and along a clamping unit of the bundling tool surrounding the article, returning it to the locking element, wherein the advancing speed of the end segment is greater in a first path portion than in a second path portion following the first. Another method step involves separating the end segment from the remaining portion of the unbroken strip retained in the bundling tool.

[0029] The advantages and advantageous or alternative embodiments of the calibration process and / or binding process thus correspond to the advantages and advantageous or alternative embodiments of the binding tool.

[0030] The aforementioned features and combinations thereof, as well as those disclosed in the general description and in the accompanying drawings or individual drawings, can be used not only individually or in the described combinations, but also in conjunction with other features, or without some of the disclosed features, without departing from the scope of the invention. Therefore, embodiments not explicitly shown and described in the drawings but which can be produced by individually combining the various features disclosed in the drawings are also part of this disclosure. Thus, embodiments and combinations of features that do not include all features of the initially presented independent technical solution are also considered disclosed. Furthermore, embodiments and combinations of features that differ from or extend beyond the feature combinations described in the dependent relationships of the technical solutions will be considered disclosed. Attached Figure Description

[0031] The exemplary embodiments will now be described in more detail with reference to the schematic diagrams. As shown here: Figure 1 This is a schematic diagram of an exemplary strapping tool; Figure 2 A schematic cross-sectional view of an exemplary embodiment of the strapping tool; and Figure 3 yes Figure 2 Details; and Figure 4 This is a schematic diagram of an exemplary strapping tool with clamping units of different sizes.

[0032] In the accompanying drawings, elements that are identical or have similar functions are given the same reference numerals. Detailed Implementation

[0033] Figure 1 An exemplary strapping tool is schematically illustrated. In this example, the strapping tool 1 has a central housing 1a with a handle unit 1b. Unlike the handle unit 1b, the central housing 1a may have a mechanical and / or electrical interface for connection with a robot. The strapping tool 1 has a replaceable clamping unit 2 for guiding the end segment 3a of the unbreakable strip 3 around the strapped item 4. The unbreakable strip 3 has a toothed portion 3b, which in this case is arranged on the outside of the unbreakable strip 3, facing away from the strapped item 4 during intended use. In the illustrated example, the unbreakable strip 3 is fed from a storage unit 1c, which houses the unbreakable strip 3, for example, in a roll. The storage unit 1c may be designed as a separate unit from the strapping tool 1.

[0034] The clamping unit 2 has an upper clamping jaw 2a and a lower clamping jaw 2b that can be opened and closed. The locking element feeding unit 5 provides a corresponding locking element 15 for the current binding process, the locking element 15 being from an external or internal memory (not shown here).

[0035] The strapping tool 1 also has a push-pull unit 6, which in this embodiment is provided with a drive device 6a that engages with the toothed portion 3b, for advancing the end portion 3a of the unbroken strip 3 along the path 7 through the provided locking element 15 and along the clamping unit 2 by means of a motor (at this time the strapped item 4 is clamped by the clamping unit 2 surrounding the strapped item 4), and returning to the provided locking element 15, and for subsequently pulling back the end portion 3a of the unbroken strip 3.

[0036] The strapping tool 1 also has a sensor unit 8 for detecting the end segment 3a pushed back into the locking element 15. In this case, with a mechanical stop element 8a, one end 3a' of the end segment 3a abuts against the mechanical stop element 8a during advancement along the path 7, thereby triggering a sensor signal. The cutting unit 9, also part of the strapping tool 1, is used to separate the end segment 3a arranged around the bundled item 4 from the remaining segments 3c of the non-broken strip 3 retained in the strapping tool 1 after the end segment 3a has been pulled back and thus the bundled item 4 has been secured. In this case, separation is accomplished by means of a blade element 9a, which moves positively upward in the y-direction to cut off and thus separate the remaining segments 3c that protrude positively upward in the X-direction on the locking element 15 after being pulled back (and then at least partially form a new end segment, which is guided around the bundled item 4 in subsequent strapping processes).

[0037] Finally, the binding tool 1 has a control unit 10, which is designed to, in normal operating mode, provide a first path portion 7a for the path 7 of the push-pull unit 6 during the push-pull process. Figure 2 The preset advance speed of the end segment 3a is larger than that of the second path segment 7b following the first path segment 7a, wherein the second path segment 7b includes a portion of the path 7 extending back into the locking element 15.

[0038] Figure 2 The path 7 is shown in detail. In the example shown here, the second path portion 7b extends from point 7y of path 7 to end point 7z of path 7, where end segment 3a is pushed back through locking element 15. In this example, the first path portion 7a extends from the starting point 7x of path 7 located at the opening of locking element 15, and end segment 3a is pushed past the starting point 7x at the start of the corresponding binding process.

[0039] The corresponding path portions 7a and 7b, more precisely their lengths, can be determined in the calibration operation mode of the control unit 10 for the corresponding clamping unit 2 used. This can be measured and / or specified using equivalent distances, such as the number of teeth in the toothed portion 3b and / or the number of encoder or motor steps in the drive unit 6a or associated motor. In this way, the behavior of the push-pull unit 6 in use can be partially or fully automatically determined based on the corresponding dimensions of the clamping unit 2, i.e., the length of the path 7 designed to be used.

[0040] Preferably, the control unit 10 is then designed to specify a lower advance speed for the end segment 3a of the first path portion 7a to the push-pull unit 6 in the calibration operation mode than in the normal operation mode, and to determine an equivalent distance for the first path portion 7a in the calibration operation mode, such as one of the equivalent distances described above. For example, this can be achieved by determining an equivalent distance for the entire path 7, for example by calculating the total number of encoder steps or the total number of teeth of the toothed portion 3b from the start of advancing the end segment 3a until the sensor signal is triggered at the endpoint 7z, and then subtracting the stored number of encoder steps or teeth corresponding to the second path portion 7b from the total.

[0041] In calibration mode, the advance speed for the second path portion 7b can be preset in normal operation mode for the first path portion 7a and the second path portion 7b of the push-pull unit 6. However, the first path portion 7a and / or the second path portion 7b may also have different advance speeds, for example, even lower than the advance speed of the second path portion in normal operation mode. In principle, the equivalent distance determined by a lower advance speed is more accurate than the equivalent distance determined by a higher advance speed. In practice, when determining the equivalent distance, it is necessary to weigh the desired increase in binding speed against the desired increase in accuracy.

[0042] The length of the second path portion 7b is preset to be as short as possible by the control unit 10 and / or the control unit 10, so the control unit 10 and / or the push-pull unit 6 in the forward direction F ( Figure 3 The non-discontinuous strip 3 is advanced on the upper part and then in the reverse direction R ( Figure 3 The corresponding switching speed between the upper and lower non-break strips 3 is a limiting factor.

[0043] The first path 7a does not necessarily have to start from the starting point 7x; it can also start from another point 7x'. In calibration mode, a higher advance speed can also be specified for the initial path portion between points 7x and 7x', such as the higher advance speed in normal operation mode. For example, the length of the initial path portion can be the length of the first path portion 7a from the starting point 7x to point 7y of the smallest clamping unit 2 used or available by the binding tool 1, and / or a shorter length.

[0044] Alternatively, or in addition to the calibration operating modes described above, the normal operating mode may also include a calibration normal operating mode. This refers to... Figure 3 Provide an example.

[0045] At the start of the binding process, the end 3a' of the unbroken strip 3 is located at the starting position 7x. After the binding process trigger signal is issued, the end 3a' and the adjacent end segment 3a are first pushed forward by the push-pull unit 6 in the forward direction F passing through the locking element 15 and along the path 7. Once the corresponding equivalent distance is reached, for example, the predetermined number of encoder or motor steps, the pushing speed is reduced when the position 7y is reached, thereby reducing the possibility of incorrect binding. When the end position 7z is reached, the sensor signal is triggered, and the push-pull unit then pulls the unbroken strip 3 back in the reverse direction R to bind the material 4 to be bound as intended.

[0046] In the calibration normal operating mode, the (particularly relative) equivalent time between the strapping process trigger signal and the sensor signal can be detected and compared with the stored (particularly relative) equivalent time. Only when the two equivalent times match can the previous normal operating mode be continued, i.e., the previous length of the first and / or second equivalent distances 7a and 7b.

[0047] If, based on the stored equivalent time, the trigger time of the sensor signal is later than the expected time, it indicates that the size of the clamping unit 2 used is larger than the clamping unit with the stored equivalent time. If, based on the stored equivalent time, the trigger time of the sensor signal is earlier than the expected time, it indicates that the size of the clamping unit 2 used is smaller than the clamping unit with the stored equivalent time. Accordingly, the control unit 10 can automatically adjust the length of the first path portion 7a according to whether the sensor signal triggers later or earlier, i.e., lengthen or shorten it accordingly, and then, in turn, adjust the stored equivalent time to the new length of the first path portion 7a. In this way, the strapping tool 1 can calibrate itself during the expected period of use and adjust the clamping units 2 of different sizes accordingly in an optimal manner.

[0048] Figure 4Exemplary clamping units 2, 2', 2'', and 2''' of different sizes are shown on an exemplary strapping tool 1. The clamping units 2, 2', 2'', and 2''' can be repeatedly replaced without damage, preferably without using tools or with a limited number and / or complexity of tools. Corresponding to the different sizes of the clamping units 2, 2', 2'', and 2''', the corresponding paths 7, 7''', and therefore, particularly the length of the first path portion 7a, also differ. On the other hand, the second path portion 7b can have the same length, as the appropriate length is determined by other characteristics of the corresponding strapping tool 1, such as the reaction speed of the control unit 10.

Claims

1. A binding tool (1) that binds items (4) without waste by means of non-breaking strips (3), the binding tool (1) comprising: - Replaceable clamping unit (2), the replaceable clamping unit (2) is used to guide the end segment (3a) of the unbroken strip (3) around the bundled item (4); - Locking feeder unit (5), which provides locking elements (15) for the non-broken strip (3); - Push-pull unit (6), which is used by means of a motor to advance the end segment (3a) of the unbroken strip (3) along the path (7) through the provided locking element (15) and along the clamping unit (2) when the bundled item (4) is clamped by the clamping unit (2), thus around the bundled item (4) and back into the provided locking element (15), and for subsequently pulling back the end segment (3a) of the unbroken strip (3). - Sensor unit (8), the sensor unit (8) is used to detect that the end segment (3a) is pushed back into the locking element (15); - Cutting unit (9), the cutting unit (9) is used to separate the end segment (3a) arranged around the bundled item (4) from the remaining segment (3c) of the unbroken strip (3) retained in the binding tool (1); Its features are, - Control unit (10), the control unit (10) is designed to, during the push-pull phase of normal operation, preset a greater push speed for the end segment (3a) of the first path portion (7a) of the path (7) than the second path portion (7b) following the first path portion (7a), the second path portion (7b) including a portion of the path (7) extending back into the locking element (15).

2. The binding tool (1) according to claim 1. Its features are, The control unit (10) is designed to: - In the calibration operation mode, for the first path portion (7a), the push-pull unit (6) is preset with a lower advancing speed for the end segment (3a) than in the normal operation mode; and - In the calibration operation mode, an equivalent distance for at least the first path portion (7a) is determined.

3. The binding tool (1) according to claim 2. Its features are, The propulsion speed of the second path section (7b) in the normal operation mode is preset to the propulsion speed of the push-pull unit (6) used for the first path section (7a) in the calibration operation mode.

4. The binding tool (1) according to claim 2. Its features are, In the calibration operation mode, the control unit (10) is adapted to determine the equivalent distance by calculating the number of motor steps of the motor of the push-pull unit (6) during the advancement of the end section (3a).

5. The binding tool (1) according to any one of claims 2 to 3. Its features are, The control unit (10) is designed to automatically deactivate the calibration operation mode after the equivalent distance has been determined once, twice or more.

6. The binding tool (1) according to any one of claims 2 to 3. Its features are, The control unit (10) is designed to automatically activate the calibration operation mode after the strapping tool (1) is turned off.

7. The binding tool (1) according to claim 1. Its features are, The control unit (10) is designed to: - In the normal operating mode, the equivalent time for the sensor unit (8) to detect that the end segment is pushed back into the locking element (15) is detected; - Check whether the detected equivalent time corresponds to the stored equivalent time for propulsion of the push-pull unit (6); and - The predetermined normal operating mode will only continue to be executed when the two equivalent times are consistent.

8. The binding tool (1) according to claim 7. Its features are, The control unit (10) is adapted to determine the equivalent time by calculating the number of motor steps in the motor of the push-pull unit (6) during the advancement of the end section (3a).

9. The binding tool (1) according to claim 7 or 8. Its features are, The control unit (10) is designed such that if the two equivalent times deviate from each other: - Activate the calibration operation mode, in which the push-pull unit (6) is preset with a lower advancing speed for the end segment (3a) than in the normal operation mode for the first path portion (7a), and an equivalent distance for at least the first path portion (7a) is determined; and / or - Check whether the detected equivalent time is greater than or less than the stored equivalent time, and if the detected equivalent time is greater, increase the first path portion (7a) with the greater propulsion speed of the end segment (3a), and if the detected equivalent time is less, decrease the first path portion (7a) with the greater propulsion speed of the end segment (3a).

10. The binding tool (1) according to claim 1. Its features are, The replaceable clamping unit (2) is or includes a fully mechanical clamping unit (2).

11. A strapping tool system comprising a strapping tool (1) according to any one of claims 1 to 10 and at least two clamping units (2, 2', 2'', 2'''), said clamping units (2, 2', 2'', 2''') having different sizes.

12. The strapping tool system as described in claim 11, Its features are, The system includes three or four different clamping units (2, 2', 2'', 2'''), which have different sizes.

13. A method for automatic calibration designed for waste-free bundling of bundled articles (4) by means of non-breaking strips (3), the method comprising the following steps: - By means of a feed motor, the end segment (3a) of the unbroken strip (3) is advanced along the path (7) through the locking element (15) and along the clamping unit (2) of the strapping tool (1) and returned to the locking element (15); - Detect the end position (7z) reached by the end segment (3a) that has been pushed into the locking element (15); - Determine the number of motor steps of the feed motor required to advance the end segment (3a) to the end position (7z); - Set a first propulsion speed for the motor stepping corresponding to the first path portion (7a) of the path (7) for future propulsion; and - Set a second propulsion speed for the motor stepping of the second path portion (7b) corresponding to the path (7) for the future propulsion, the second propulsion speed being lower than the first propulsion speed, the second path portion (7b) following the first path portion (7a).

14. The method according to claim 13, Its features are, During the advance, the end section (3a) is advanced around the bundled item (4).

15. A method for binding bundled items (4) without waste using non-breaking strips (3), the method comprising the following steps: - The end segment (3a) of the unbroken strip (3) is advanced along the path (7) through the locking element (15) and along the clamping unit (2) of the strapping tool (1) and returned to the locking element (15), wherein the advancing speed of the end segment (3a) is greater in the first path portion (7a) of the path (7) than in the second path portion (7b) of the path (7) following the first path portion (7a); - Separate the end segment (3a) from the remaining segment (3c) of the unbroken strip (3) in the binding tool (1).

Images