DEVICE FOR ROLLING OFF A FLEXIBLE ROD-SHAPED OBJECT

Description

[0001] The present invention relates to a device for rolling a flexible rod-shaped object according to the preamble of claim 1.

[0002] Rod-shaped objects within the meaning of the present invention are, for example, cable pull-in springs. These are frequently stored in reels and removed from them when needed. After use, such pull-in springs are returned to the reel. The typical application involves inserting the pull-in spring into a conduit at a first opening, for example, at a junction box, and advancing it until it emerges from the conduit at a second opening. Then, a cable to be pulled in is attached to the tip of the pull-in spring, and the spring is pulled out of the conduit until the cable exits at the first opening.

[0003] A typical design for such unwinding devices, as described above, involves a drum on the inside of which the rod or draw-in spring is held in its wound state. This allows the natural preload of the draw-in spring to ensure that the rod or draw-in spring rests against the inside of the drum.

[0004] To cut the cables to the correct length before pulling them through, it is desirable to know the length of the pulling spring taken from the unwinding device. Unwinding devices equipped with an integrated length measuring device are therefore known. Such solutions are disclosed, for example, in US 9,417,05 B and US 4,092,780 A. This makes these unwinding devices relatively bulky and, due to the necessary deflections, also inaccurate.

[0005] From WO 2019 / 195893 A1, US 6,016,609 A and other publications, unwinding devices are known in which a cord, tape or flexible rod can be unwound from the outside of a drum and a length measuring device is then provided. These solutions are poorly suited for flexible but relatively rigid draw-in springs.

[0006] WO 2018 / 112411 A1 describes a winding device in which the rotation of the drum is measured to obtain information about the length of the draw-in spring taken from the winding device. Since the circumferential length of the draw-in spring in the drum naturally depends on the thickness of the winding, such a device is very inaccurate.

[0007] The object of the invention is to avoid these disadvantages and to provide a device of the type described above that is compact, accurate, practical, and aesthetically pleasing. A further object is to provide a solution that is easy to maintain.

[0008] According to the invention, these problems are solved by the features of claim 1.

[0009] A significant advantage of the solution according to the invention is that the interior of the drum, which is no longer needed to hold the rod-shaped object, is partially occupied by the length measuring device. Typically, the length measuring device is thus also located inside the housing, apart from a display and, optionally, a reset button. This allows the length measuring device to be protected from external influences, such as contamination.

[0010] The solution according to the invention makes it possible for the rod-shaped object to pass through the length measuring device immediately after leaving the winding on the drum and to be guided laterally out of the housing by the device. Due to the minimal deflections, high accuracy is achieved.

[0011] To detach the rod-shaped object from the coil, it is necessary to apply a lateral, inward force to the object. Frictional resistance can be minimized, in particular, by ensuring that the length measuring device has at least one roller over which the object is guided.

[0012] The solution according to the invention is designed such that a measuring roller is provided and that the length measuring device detects and evaluates the rotation of the measuring roller. Preferably, detection via a Hall sensor can be used. This measuring principle is robust and not very susceptible to contamination. Since, apart from the measuring roller, no moving parts are provided, the system is low-wear and durable. If the Hall sensor is mounted independently of the measuring roller, a design can be presented that is particularly maintenance-friendly due to its easy disassembly. Thus, the Hall sensor can preferably be arranged in an assembly with an evaluation circuit and a display element.

[0013] Maintenance is particularly easy if the assembly is mounted on a cover element that can be removed from the housing. This makes tasks such as replacing the batteries in the length measuring device especially simple.

[0014] Naturally, and according to the invention, in systems with a measuring roller, it must be ensured that the measuring roller is in constant contact with the rod-shaped object to avoid measurement errors. If the preload of the object is insufficient to guarantee secure contact with the measuring roller, the measuring roller can be preloaded by a spring.

[0015] It is particularly advantageous if the measuring roller is mounted on a swivel arm whose pivot axis preferably lies in an imaginary plane perpendicular to the drum's axis of rotation. The pivot axis of the swivel arm itself is thus also perpendicular to the drum's axis of rotation, without necessarily intersecting it. As the object winds onto or off the drum, it spreads across its width, which consequently leads to a change in the object's exit angle from the length measuring device. This can also be compensated for by the movement of the swivel arm.

[0016] As the object is wound onto the drum, the inner diameter of the coil naturally decreases, depending on how many layers are already in contact with the inside of the drum. To account for this and to maintain an optimal angle of impact for the object regardless of the drum's fill level, the length measuring device can be mounted on the housing so that it can pivot about an axis. It is advantageous if the pivot axis is arranged essentially parallel to the drum's axis of rotation.

[0017] A preferred embodiment of the invention provides that the length measuring device is arranged in the region of the drum's circumference. This means that the length measuring device is positioned as far as possible from the drum's center point, so that the object, when inserted, strikes the inside of the drum or the existing coil as tangentially as possible. It is also advantageous if the device has a handle and if the length measuring device is located in the area of ​​the handle. This results in a small distance between the handle and the outlet opening, which is beneficial for handling.

[0018] Further usability is achieved if the housing has a central recess in which a storage box is located. This allows small parts and accessories, such as alternative draw spring tips, to be stored within easy reach in the device.

[0019] From a design perspective, it is advantageous if the drum is mounted at the rear of the housing.

[0020] A safe and consistent movement of the object through the length measuring device is achieved if the length measuring device has a measuring element and at least one rear guide for the object arranged between the measuring element and the drum. The area between the measuring element and the drum should be defined such that it begins at the point on the measuring element that is closest to the outlet of the housing and ends where the rod typically contacts the drum or coil. According to the preferred embodiment above, the measuring element is the measuring wheel; otherwise, it could be, for example, an optical measuring element. The guide ensures that the rod is always guided smoothly through the measuring element, even if, for example, torsional moments occur that could cause lateral movements.

[0021] Improved object guidance can also be achieved by providing the length measuring device with a measuring element and at least one front guide for the object located between the measuring element and the exit opening. A combination of front and rear guides can, in particular, prevent the object from tilting.

[0022] The guides can be designed as sliding guides, preferably as bracket or ring guides. An effective limitation of the range of motion in the area of ​​the measuring wheel or other measuring element is essential.

[0023] It is particularly advantageous if the rear and / or front guides allow for some play in guiding the object. This significantly reduces friction, as the object is either not in contact with the guide at all or only with minimal force. It is also beneficial if the play in the radial direction relative to the drum's axis of rotation is smaller than in a direction perpendicular to it, i.e., a direction parallel to the drum's axis of rotation. This means that a greater degree of lateral movement of the object, which is inevitable during winding or unwinding, is permitted than movement within the plane of the drum, which would also have a greater impact on the measurement result, as the object would at least tilt relative to the measuring roller or even lose contact with it.

[0024] To reduce the friction that occurs, the guides can also be designed as guide rollers.

[0025] From a design perspective, it is advantageous if at least one rear guide is formed in one piece with a holder for the measuring roller.

[0026] A further improvement can be achieved if a rear guide is designed as a rod attached to the housing. In this way, only the movement within the plane of the drum is limited, without hindering the lateral movement necessary for the uniform formation of the winding.

[0027] Particularly good guidance effectiveness is achieved when at least one guide is arranged in the area of ​​the measuring element.

[0028] It is advantageous if the housing consists of two housing halves. These can then be manufactured as injection-molded components.

[0029] The present invention will now be explained in more detail with reference to the embodiments illustrated in the exemplary figures. These show: Fig. 1 a device according to the invention in an oblique front view; Fig. 2 the device of Fig. 1 in an alternative oblique view; Fig. 3 a detail of Fig. 2 with the cover element removed; Fig. 4 a cut oblique view with section along line IV - IV in Fig. 2 ; Fig. 5 a sectional oblique view accordingly Fig. 4 from a different perspective; Fig. 6 a detail of the length measuring device; Fig. 7 the device of Fig. 1 bis Fig. 6 in a rear view with the rear housing half removed; and Fig. 8, Fig. 9 , Fig. 10 , Fig. 10a , Fig. 11 and Fig. 12 Further details of the length measuring device.

[0030] The device of Fig. 1 The device has a housing 1, which consists of an upper housing half 2 and a lower housing half 3 and on which a handle 4 is provided. A flexible object 5, namely a retraction spring 6 with a retraction spring tip 7, emerges from the interior of the housing 1 through an exit opening 8 and can be pulled out or pushed in as required.

[0031] In the central area of ​​the upper housing half 2, a removable cover element 9 is provided, which carries a display element 10 and a reset button 11 with which the currently displayed length can be reset. Next to this is a removable storage box 12 in which a user of the device can store small parts, such as spring tips. The storage box 12 is secured to the housing 1 by a locking element.

[0032] In the Fig. 3 The central recess 14 of the upper housing half 2 of the housing 1 with the opening edge 14a is shown, which results when the removable cover element 9 and the removable receiving box 12 are removed.

[0033] Inside the housing 1, a measuring roller 15 is provided, which is mounted on a swivel arm 16. The swivel arm 16 is pivotally mounted on a bracket 18 via a pivot axis 17, with the swivel arm 16 and measuring roller 15 being biased against the object 5 by a spring 35. The measuring roller 15, swivel arm 16, and bracket 18 are referred to here as a length measuring device 19.

[0034] Inside the housing 1, a drum 20 is rotatably mounted in a bearing 21, which bearing 21 is centrally located on the lower housing half 3. The inner surface 20a of the drum 20 is designed to receive the Fig. 5 The indicated wrap 24 of object 5 is provided.

[0035] It is in Fig. 5 It is also evident that two semicircular permanent magnets 23a and 23b are provided in the measuring roller 15, which generate a rotating magnetic field when the measuring roller 15 is rotated.

[0036] Fig. 6 Figure 25 shows that a module 25 is mounted on the inside of the cover element 9. The module 25 consists of a Hall sensor 27 and an evaluation circuit 28, which are powered by a battery 26. The Hall sensor 27 detects the rotating magnetic field of the measuring roller 15, and the length of the object 5 drawn over the measuring roller 15 can thus be calculated. (Not visible in Figure 26.) Fig. 6 The display element 10 and the reset button 11 are arranged externally on the assembly 25. The separate arrangement of the assembly 25 on the cover element 9 facilitates maintenance and provides mechanical decoupling from the measuring roller 15.

[0037] The pivot arm 16 can be pivoted about a further pivot axis 29, which further pivot axis 29 is parallel to the axis of rotation 22 of the drum 20, which is perpendicular to an imaginary plane defined by the sealing surface between the upper housing half 2 and the lower housing half 3. The pivot axis 17 of the pivot arm 16 is parallel to this imaginary plane.

[0038] Fig. 8 Figure 1 shows in detail the rear guide 33a, designed as a ring guide, for the object 5, which is arranged between the measuring element – ​​here in the form of the measuring roller 15 – and the drum 20 (not visible here). The ring guide is open at the front, which facilitates the insertion of the object. A front guide 34 for the object 5 is formed immediately adjacent to the outlet opening 8 in the form of a closed channel.

[0039] A retraction safety device 31 in the form of a spring-loaded flap at the edge of the exit opening 8 is designed to prevent unintentional complete retraction of the object 5. As soon as the thickened area 5a at the transition point to the retraction spring tip 7 reaches the exit opening 8, it wedges itself in the retraction safety device 31 and limits the insertion. However, withdrawal is not hindered. Furthermore, in Fig. 8 The pivoting movement of the pivoting arm 16 about the pivot axis 17 is indicated by the double arrow 32.

[0040] In Fig. 9 The bracket 18 is shown with the measuring roller broken off, the view directed from the removed rear housing half towards the front housing half 2, on which the bracket 18 is attached. The rear guide 33a is located directly next to the recess 36 and is therefore in the area of ​​the measuring element. The recess 36 serves to enable contact between the measuring roller 15 and the object 5. The front guide 34 is also part of the bracket 18 and is likewise located in the area of ​​the measuring element.

[0041] An additional rear guide 33b, in the form of a rod parallel to the axis of rotation 22, is attached to the front housing half 2. This additional rear guide 33b guides the object 5 only in the radial direction of the drum 20. Its purpose is to prevent the object 5 from moving laterally in the direction of arrow 37 and thus being unable to be optimally detected by the measuring roller 15, in cases of very strong tension on the object 5 and / or in situations where rotation of the drum 20 is difficult.

[0042] In the Fig. 10 with the detail in Fig. 10a The situation is evident in a representation in which the part of the housing 1 encompassing the handle 4 has broken off.

[0043] The Fig. 11 and Fig. 12Figure 1 shows the bracket 18 in detail, with particular emphasis on the opening 38, which is bounded by the rear guide 33a. Preferably, the opening 38 is oval, so that its extent in the plane of symmetry, i.e., in the direction of the double arrow 39, is slightly greater than its extent perpendicular to it. In any case, there should be a clearance of a few tenths of a millimeter relative to the rod, which is not visible here. The front guide 34 can be seen as a guide channel on the opposite side of the bracket 18.

[0044] The device according to the invention makes it possible to reliably and accurately determine the length of a rolled-out object.

Claims

1. Device for unrolling a flexible rod-shaped object (5) with a housing (1), a rotatable drum (20) which is arranged inside the housing (1) and has a cylindrical inner surface (20a) designed to support the object (5), wherein the housing (1) has an outlet opening (8) through which the object (5) can be guided out of or into the interior of the housing (1), and wherein a length measuring device (19) is provided for measuring the length of the object (5) guided out or in, characterised in that the length measuring device (19) is arranged substantially inside the rotatable drum (20) and is attached to the housing (1), and in that a measuring roller (15) is provided which is permanently in contact with the object (5) and whose rotation is detected and evaluated by the length measuring device (19).

2. Device according to claim 1, characterised in that the length measuring device (19) has at least one roller over which the object (5) is guided.

3. Device according to claim 1 or 2, characterised in that the length measuring device (19) has a Hall sensor (27) which is preferably attached independently of the measuring roller (15).

4. Device according to claim 3, characterised in that the Hall sensor (27) is arranged in an assembly (25) with an evaluation circuit (28) and a display element (10) and in that the assembly (25) is preferably arranged on a cover element (9) that can be removed from the housing (1).

5. Device according to one of claims 1 to 4, characterised in that the measuring roller (15) is preloaded by a spring (35).

6. Device according to claim 5, characterised in that the measuring roller (15) is mounted on a pivot arm (16), the pivot axis (17) of which is preferably located in an imaginary plane that is perpendicular to the axis of rotation (22) of the drum (20).

7. Device according to one of claims 1 to 6, characterised in that the length measuring device (19) is pivotably mounted on the housing (1) about a further pivot axis (29), which is preferably arranged substantially parallel to the axis of rotation (22) of the drum (20).

8. Device according to one of claims 1 to 7, characterised in that the length measuring device (19) is arranged in the region of the circumference of the drum (20).

9. Device according to one of claims 1 to 8, characterised in that the housing (1) has a handle (4) and in that the length measuring device (19) is arranged in the region of the handle (4).

10. Device according to one of claims 1 to 9, characterised in that the housing (1) has a central recess (14) in which a receiving box (12) is arranged.

11. Device according to one of claims 1 to 10, characterised in that the length measuring device (19) has a measuring element and at least one rear guide (33a, 33b) for the object (5) arranged between the measuring element and the drum (20).

12. Device according to one of claims 1 to 11, characterised in that the length measuring device (19) has a measuring element and at least one front guide (34) for the object (5) arranged between the measuring element and the outlet opening (8).

13. Device according to one of claims 11 or 12, characterised in that the guide (33a, 33b; 34) guides the object with play and in that the play in the radial direction relative to the axis of rotation (22) of the drum (20) is smaller than relative to a direction perpendicular thereto.

14. Device according to one of claims 11 to 13, characterised in that at least one rear guide (33a) is formed integrally with a holder (18) for the measuring roller (15) and / or as a rod attached to the housing (1).

15. Device according to one of claims 11 to 14, characterised in that at least one guide (33a, 33b; 34) is arranged in the region of the measuring element.