Machine for cutting tubes

Abstract

The present invention relates to a machine for cutting tubes (1), having a tube supply device (2), a cutting device (3) and a control unit (4). The tube supply device (2) comprises two tube supports (5), a tube advancing block (8) with thrust pieces (9) arranged between the tube supports (5), and a tube advancing actuator (12) which is controllable by the control unit (4) and by means of which the tube advancing block (8) is displaceable parallel to a cutting plane (6) and the displacement of which in the direction of the tube supports (5) causes an increasing deflection of the tube (7) to be cut and resting against the tube supports (5), and is accompanied by the tube advancing actuator (12) exerting an ACTUAL tube advancing force on the tube advancing block (8). The cutting device (3) comprises a rotatable cutting disc (14) and a cutting disc advancing actuator (17) which is controllable by the control unit (4) and by means of which the cutting disc (14) is displaceable in the cutting plane (6). The control unit (4) is designed to control the tube advancing actuator (12) depending on the current ACTUAL tube advancing force and the cutting disc advancing actuator (17) depending on the current ACTUAL cutting disc rotational speed.

Description

[0001] Machine for cutting hoses

[0002] The present invention relates to a machine for cutting hoses in a cutting plane with a hose feeding device and a cutting device.

[0003] Such hose cutting machines are known in many different forms and are used in practice worldwide. As an example, reference is made here to the applicant's international patent application WO 2017 202690 Al, in which such a machine is described in detail.

[0004] Hose cutting machines are typically used to cut a hose to a desired length before it is further processed as intended.

[0005] Especially when the cut (lengthened) hoses are subsequently fitted with connection fittings at the ends and used as hydraulic lines in a high-pressure hydraulic application, there are very high demands on the quality of the cut, both with regard to the geometry of the cut (as perpendicular as possible to the axis of the hose) and with regard to the cleanliness of the cut (e.g. no fraying).

[0006] Such deviations from the ideal cutting path potentially result in reduced reliability of the hydraulic line in question, the failure of which can have serious consequences in individual cases. The production of ideal cuts is made particularly difficult by the fact that hoses used in the manufacture of hydraulic lines are typically reinforced with a layer (for example, braided from steel wire), meaning that extremely different materials (rubber or plastic on the one hand and steel wire on the other) must be cleanly severed with a single cut.

[0007] To meet these challenges, hose cutting machines, such as those described in the aforementioned WO 2017 202690 Al, first bend the hose to be cut slightly and then cut it in the bent section with a rotating cutting blade (cutting disc). This ensures that the hose opens during cutting, so that the cutting disc only makes contact with the hose at its cutting edge, and not with its flanks against the already cut hose. This prevents the input of unwanted frictional heat and thus the melting of the rubber or plastic layer, which improves the quality of the cut.

[0008] The present invention is based on the objective of providing a machine for cutting hoses of the aforementioned type, which is characterized by improved practicality, in particular with regard to the quality of the cut and its reproducibility.

[0009] The problem is solved by the machine for cutting hoses according to claim 1. Preferred embodiments are described in claims 2 to 8.

[0010] The machine according to the invention for cutting hoses in a cutting plane, comprising a hose support device, a cutting device, and a control unit, has the following features: the hose support device comprises (at least) two hose supports spaced apart from each other and arranged on both sides of the cutting plane, suitable for receiving (clamping) a hose to be cut; a hose feed block with pressure pieces arranged on both sides of the cutting plane between the hose supports; and a hose feed actuator controllable by the control unit, by means of which the hose feed block can be displaced parallel to the cutting plane and whose displacement in the direction of the hose supports causes an increasing deflection of the hose to be cut, which is in contact with the hose supports (and causes the hose to be clamped between the hose supports and the hose feed block), and is thus accompanied bythat the hose feed actuator exerts an actual hose feed force on the hose feed block; the cutting device comprises a cutting disc rotatable in the cutting plane by a rotary drive at an actual cutting disc rotational speed, and a cutting disc feed actuator controllable by the control unit, by means of which the cutting disc can be displaced in the cutting plane; the control unit is configured to control the hose feed actuator as a function of the instantaneous actual hose feed force, and to control the cutting disc feed actuator as a function of the instantaneous actual cutting disc rotational speed.

[0011] The invention is based on the realization that the synergistic combination according to the invention of a force-controlled hose feed and a speed-controlled cutting blade feed enables a hose cutting machine that is particularly suitable for practical use.

[0012] The force-controlled hose feed allows the instantaneous deflection of the hose to be adjusted to both the specific hose and the current cutting phase. This prevents, for example, excessive opening of the partially cut hose during a later cutting phase, thus further improving the cut. Similarly, varying resistance forces specific to the hose, which counteract its deflection, can be individually taken into account.

[0013] In contrast, the speed-controlled cutting disc feed allows the cutting disc to be brought into contact with the hose independently of the hose's curvature. The cutting disc's penetration speed into the hose (cutting disc feed speed) can be precisely adjusted to the current cutting phase via the instantaneous cutting disc rotation speed, and thus controlled, for example, depending on whether a reinforcing layer or a rubber layer of the hose is currently being cut.

[0014] By combining these two control approaches, a cutting process can be realized that is specifically adapted to the hose used and the characteristics of the different cutting phases, thereby significantly improving the quality of the cut.

[0015] The automated control by the control unit enables a high reproducibility of the cutting operations and thus a high level of process reliability, regardless of the experience and manual skill of the operator.

[0016] The following section explains some features and aspects of the machine according to the invention in more detail:

[0017] In this context, a hose is understood to be a flexible, elongated hollow body, usually with a round cross-section, whose cavity is suitable for the flow of a fluid. A hose can be constructed from various layers of different materials to meet the desired requirements regarding pressure, media resistance, and mechanical strength. In particular, a hose can have a reinforcing layer and a rubber or plastic layer encasing the reinforcing layer.

[0018] A cutting plane is the plane in which the cutting disc cuts the hose. The cutting disc moves within the cutting plane and is rotatable around an axis of rotation within this plane. This axis of rotation is perpendicular to the cutting plane.

[0019] The hose to be cut can be clamped between the (at least) two hose supports and the pressure pieces of the hose feed block. By moving the hose feed block further towards the hose to be cut, the hose can be bent (i.e., an arc-shaped path can be forced onto the hose). When a rotating cutting disc penetrates the bent section of hose and cuts through it, the hose opens apart at the cut points.

[0020] The phrase "a feed actuator can be controlled by the control unit" expresses the fact that the feed actuator can be controlled by the control unit and thus set in motion. A feed actuator can, in particular, be designed as a linear actuator, for example, as an electric linear motor.

[0021] The wording that the hose feed block can be moved by means of the hose feed actuator expresses that the hose feed block can be moved by the hose feed actuator (with appropriate control by the control unit).

[0022] The actual hose feed force is the force exerted (transmitted) by the hose feed actuator on the hose feed block or by the pressure pieces of the hose feed block on the hose to be cut.

[0023] The formulation that the hose feed actuator is controlled depending on the current actual hose feed force t expresses that the current actual hose feed force t is an input variable on the basis of which the movement of the hose feed actuator (and thus the movement of the hose feed block) is controlled or regulated.

[0024] Analogously, the formulation that the cutting disc feed actuator is controlled depending on the current actual cutting disc speed means that the current actual cutting disc speed is an input variable on the basis of which the movement of the cutting disc feed actuator (and thus the movement of the cutting disc or the cutting disc feed speed) is controlled or regulated.

[0025] According to a preferred embodiment, the machine comprises a force measuring device by means of which the instantaneous actual hose feed force can be determined and transmitted to the control unit, and a speed measuring device by means of which the instantaneous actual cutting disc rotational speed can be determined and transmitted to the control unit. Furthermore, it is advantageously possible to store a target hose feed force in the control unit and to configure the control unit to control the hose feed actuator as a function of the instantaneous actual hose feed force and the target hose feed force, in particular such that if the instantaneous actual hose feed force is less than the target hose feed force, the control unit actuates the hose feed actuator in such a way that it moves the hose feed block further towards the cutting disc.

[0026] In this way, it can be achieved that the actual hose feed force approximates the target hose feed force again by appropriately controlling the hose feed actuator.

[0027] Furthermore, the control unit can advantageously be configured to control the hose feed actuator depending on the current actual hose feed force and the target hose feed force in such a way that, in the event that the current actual hose feed force is greater than the target hose feed force, the control unit controls the hose feed actuator in such a way that it moves the hose feed block further away from the cutting disc.

[0028] The target hose feed force can be a hose-specific or non-hose-specific value that remains constant throughout the entire cutting phase (constant target value) or that changes during the cutting phase (dynamic target value) in order to, for example, achieve different bending radii of the hose during the initial cutting and final cutting phases. Preferably, the control unit is configured to control the hose feed actuator in such a way that its hose feed speed does not exceed a maximum hose feed speed.

[0029] According to another preferred embodiment, a target cutting disc speed can be stored in the control unit and the control unit is configured to control the cutting disc feed actuator depending on the current actual cutting disc speed and the target cutting disc speed by adjusting the cutting disc feed rate, in particular such that if the current actual cutting disc speed is lower than the target cutting disc speed, the control unit controls the cutting disc feed actuator in such a way that the cutting disc feed rate is reduced.

[0030] Furthermore, the control unit can advantageously be configured to control the cutting disc feed actuator depending on the current actual cutting disc speed and the target cutting disc speed, by making the cutting disc feed speed adjustable in such a way that, in the event that the current actual cutting disc speed is greater than the target cutting disc speed, the control unit controls the cutting disc feed actuator in such a way that the cutting disc feed speed is increased.

[0031] The cutting disc feed rate is the speed at which the cutting disc is moved (moved) relative to the hose supports by the cutting disc feed actuator.

[0032] The target cutting disc speed can be – analogous to the target hose feed force – a hose-specific or non-hose-specific value that does not change during the entire cutting phase (constant target value) or that changes during the cutting phase (dynamic target value) in order to take into account, for example, different requirements when cutting through different material layers of the hose (e.g., during the initial cutting or final cutting phase).

[0033] Such a dynamic target value can be determined or adjusted, for example, depending on the feed distance already covered by the cutting disc and / or the penetration depth of the cutting disc into the hose.

[0034] The penetration depth of the cutting disc into the hose can be determined by calculating the feed distance of the cutting disc that has been traveled since the cutting disc penetrated the hose.

[0035] The penetration of the cutting disc into the hose can be detected by the control unit through a sudden drop in the actual cutting disc rotation speed when the cutting disc is moved towards the hose.

[0036] The control unit is particularly well-suited to control the cutting disc feed actuator in such a way that the cutting disc feed speed does not exceed a maximum cutting disc feed speed.

[0037] The machine can be implemented in two fundamentally different designs, in that either the hose feed block is horizontally displaceable by the hose feed actuator and the cutting disc by the cutting disc feed actuator, or the hose feed block is vertically displaceable by the hose feed actuator and the cutting disc by the cutting disc feed actuator.

[0038] The terms horizontal and vertical refer to the situation in which the machine according to the invention is positioned and set up as intended.

[0039] According to a further preferred embodiment of the invention, the control unit is configured to detect a complete severing of a reinforcement layer of the hose to be cut by an increase in the IST cutting disc rotational speed, and, triggered by the detection of the complete severing of the reinforcement layer, to control the hose feed actuator in such a way that the IST hose feed force is reduced, in particular by moving the hose feed block away from the hose supports.

[0040] This prevents the cutting disc from cutting through the uncut rubber layer too quickly during the final phase of cutting the hose (after the reinforcement layer has already been cut through), causing it to fray.

[0041] Completely cutting through the reinforcement layer leads to an increase in the actual speed of the cutting disc (I ST cutting disc speed), because the frictional resistance opposing the rotating cutting disc decreases significantly after completely cutting through the reinforcement layer, as the cutting disc is then only slowed down by the relatively soft rubber or plastic layer of the hose.According to a further preferred embodiment of the invention, the hose feed device and the cutting device are arranged such that, when a hose to be cut is clamped as intended between the hose feed block and the hose supports, a hose axis of a hose section of the hose to be cut arranged in the cutting plane approaches radially to the axis of rotation of the cutting disc during cutting, or a hose axis of a hose section of the hose to be cut arranged in the cutting plane is guided tangentially past the axis of rotation of the cutting disc during cutting.

[0042] The two variants differ essentially in the path along which the hose is moved when being cut, in relation to the axis of rotation of the cutting disc.

[0043] In the first variant, the hose (or the hose axis) is moved radially towards the axis of rotation of the cutting disc when cut (by the hose feed actuator and / or the cutting disc feed actuator) (see Fig. 2A).

[0044] In the second variant, however, the hose (or the hose axis) is guided tangentially past the axis of rotation of the cutting disc when cutting (see Fig. 2B).

[0045] Exemplary embodiments of the invention are explained in more detail below with reference to the schematic drawing. Fig. 1 shows a schematic representation of a machine according to the invention for cutting hoses (hose cutting machine) in a top view, and Figs. 2A & B show two different exemplary embodiments of a hose cutting machine according to the invention, each in a side view of the cutting plane.

[0046] Fig. 1 shows a schematic representation of a machine according to the invention for cutting hoses (hose cutting machine) 1 .

[0047] The hose cutting machine 1 has a machine frame 1R, a hose feeding device 2, a cutting device 3 and a control unit 4.

[0048] The hose support device 2 comprises two hose supports 5, spaced apart from each other, arranged on both sides of a cutting plane 6 and accommodating a hose 7 to be cut, and a hose feed block 8 with two pressure pieces 9, arranged on both sides of the cutting plane 6 and between the hose supports 5.

[0049] The hose axis 10 of the hose section 11 arranged in the separation plane 6 is essentially perpendicular to the separation plane 6.

[0050] A hose feed actuator 12 and a force measuring device 13 are also part of the hose feed device 2 .

[0051] The hose feed actuator 12 can be controlled by the control unit 4 and thus set in motion, causing a displacement (movement) of the hose feed block 8 parallel to the cutting plane 6. A displacement of the hose feed block 8 in the direction of the hose supports 5 (or in the direction of the hose 7 to be cut) causes an increasing deflection of the hose 7. The hose feed actuator 12 exerts an instantaneous hose feed force on the hose feed block 8 and thus on the hose 7 to be cut, which can be determined by the force measuring device 13 and transmitted to the control unit 4.

[0052] A target hose feed force t is stored in control unit 4. If the current actual hose feed force t is less than the target hose feed force t, control unit 4 controls the hose feed actuator 12 such that it moves (moves) the hose feed block 8 further towards the cutting device 3 (or towards a cutting disc 14 of the cutting device 3).

[0053] The cutting device 3 comprises the cutting disc 14, a rotary drive 15, a speed measuring device 16 and a cutting disc feed actuator 17.

[0054] The rotary drive 15 allows the cutting disc 14, arranged in the cutting plane 6, to be rotated about a rotary axis 18 at an actual cutting disc speed. The cutting disc feed actuator 17 can be controlled by the control unit 4 and thus set in motion, causing a displacement (movement) of the cutting disc 14 in the cutting plane 6, particularly in the direction of the hose 7 to be cut.

[0055] The current actual cutting disc speed can be determined by the speed measuring device and transmitted to the control unit. A target cutting disc speed is stored in the control unit. If the current actual cutting disc speed is lower than the target cutting disc speed, the control unit controls the cutting disc feed actuator such that the cutting disc feed speed is reduced (possibly to zero). Figures 2A and 2B show two different embodiments of a hose cutting machine 1j according to the invention, each in a side view of the cutting plane 6.

[0056] The two embodiments differ only in the path along which the hose 7 is moved when being cut, in relation to the axis of rotation 18 of the cutting disc 14.

[0057] Figures 2A and 2B show the hose 7 to be cut (with the hose axis 10 of the hose section 11 located in the cutting plane 6) and the pressure pieces 9 in two different positions during the cutting process:

[0058] In the first position, where hose 7 and pressure pieces 9 are shown with dotted lines, hose 7 is

[0059] (still) spaced apart from the cutting disc 14 .

[0060] Subsequently, the hose 7 is moved by the hose feed actuator 12 and / or the cutting disc feed actuator 17 along a dashed path 19A, 19B with respect to the axis of rotation 18 of the cutting disc 14 and moved into the second position, in which hose 7 and

[0061] Printed pieces 9 are shown with solid lines.

[0062] According to Fig. 2A, when cut (by the hose feed actuator 12 and / or the cutting disc feed actuator 17), the hose 7 (or the hose axis 10) is moved radially towards the axis of rotation 18 of the cutting disc 14 along path 19A (radial hose guidance). According to Fig. 2B, however, when cut along path 19B, the hose 7 (or the hose axis 10) is guided tangentially past the axis of rotation 18 of the cutting disc 14 (tangential hose guidance).

[0063] Depending on the nature of the hose 7 to be cut (especially with regard to the thickness and material of the reinforcement), a radial or tangential hose routing can offer advantages.

[0064] The exemplary embodiment according to Figure 1 can have either a radial hose routing according to Figure 2A or a tangential hose routing according to Figure 2B.

[0065] Reference symbol list

[0066] Machine for cutting hoses 1

[0067] Hose feed device 2

[0068] Separating device 3

[0069] Control unit 4

[0070] Hose supports 5

[0071] Separation plane 6

[0072] Hose 7

[0073] Hose feed block 8

[0074] Printed pieces 9

[0075] Hose axle 10

[0076] Hose section 11

[0077] Hose feed actuator 12

[0078] Force measuring device 13

[0079] Cutting disc 14

[0080] Rotary drive 15

[0081] Speed ​​measuring device 16

[0082] Cutting disc feed actuator 17

[0083] axis of rotation 18

[0084] Lanes 19A, 19B

Claims

Claims 1. Machine for cutting hoses (1) in a cutting plane (6) with a hose holding device (2), a cutting device (3) and a control unit (4), with the following features: the hose holding device (2) comprises two spaced-apart hose supports (5) arranged on both sides of the cutting plane (6), suitable for receiving a hose (7) to be cut, a hose feed block (8) with pressure pieces (9) arranged on both sides of the cutting plane (6) between the hose supports (5), and a hose feed actuator (12) controllable by the control unit (4), by means of which the hose feed block (8) is displaceable parallel to the cutting plane (6) and whose displacement in the direction of the hose supports (5) causes an increasing deflection of the hose (7) to be cut, which is in contact with the hose supports (5), and is accompanied by the fact that the hose feed actuator (12) IST hose feed force exerted on the hose feed block (8);The cutting device (3) comprises a cutting disc (14) rotatable in the cutting plane (6) by a rotary drive (15) at an IST cutting disc rotational speed, and a cutting disc feed actuator (17) controllable by the control unit (4), by means of which the cutting disc (14) can be displaced in the cutting plane (6); the control unit (4) is configured to; to control the hose feed actuator (12) depending on the current actual hose feed force, and to control the cutting disc feed actuator (17) depending on the current actual cutting disc speed.

2. Machine (1) according to claim 1 comprising a force measuring device (13) by means of which the instantaneous IST hose feed force can be determined and transmitted to the control unit (4), and a speed measuring device (16) by means of which the instantaneous IST cutting disc speed can be determined and transmitted to the control unit (4).

3. Machine (1) according to one of the preceding claims, wherein a target hose feed force t can be stored in the control unit (4), and the control unit (4) is configured to control the hose feed actuator (12) depending on the instantaneous actual hose feed force t and the target hose feed force t, in particular such that if the instantaneous actual hose feed force t is less than the target hose feed force t, the control unit (4) controls the hose feed actuator (12) in such a way that it moves the hose feed block (8) further in the direction of the cutting disc (14).

4. Machine (1) according to claim 3, wherein the control unit (4) is configured to control the hose feed actuator (12) such that its hose feed speed does not exceed a maximum hose feed speed.

5. Machine (1) according to one of the preceding claims, wherein a target cutting disc speed can be stored in the control unit (4), and the control unit (4) is configured to control the cutting disc feed actuator (17) depending on the current actual cutting disc speed and the target cutting disc speed by adjusting a cutting disc feed rate, in particular such that if the current actual cutting disc speed is less than the target cutting disc speed, the control unit (4) controls the cutting disc feed actuator (17) in such a way that the cutting disc feed rate is reduced.

6. Machine (1) according to claim 5, wherein the control unit (4) is configured to control the cutting disc feed actuator (17) such that the cutting disc feed speed does not exceed a maximum cutting disc feed speed.

7. Machine (1) according to one of the preceding claims, wherein the hose feed block (8) is horizontally displaceable by the hose feed actuator (12) and the cutting disc (14) is horizontally displaceable by the cutting disc feed actuator (17), or the hose feed block (8) is vertically displaceable by the hose feed actuator (12) and the cutting disc (14) is vertically displaceable by the cutting disc feed actuator (17).

8. Machine (1) according to one of the preceding claims, wherein the control unit (4) is configured to ensure complete cutting of a reinforcing layer of the hose (7) to be cut to detect an increase in the IST cutting disc rotation speed, and triggered by the detection of the complete cutting of the reinforcement layer, to control the hose feed actuator (12) in such a way that the IST hose feed force is reduced, in particular by moving the hose feed block (8) away from the hose supports (5).

9. Machine (1) according to one of the preceding claims, wherein the hose feed device (2) and the cutting device (3) are arranged such that, when a hose (7) to be cut is clamped as intended between the hose feed block (8) and the hose supports (5), a hose axis (10) of a hose section (11) of the hose (7) to be cut arranged in the cutting plane (6) approaches radially to the axis of rotation (18) of the cutting disc (14) when cutting, or a hose axis (10) of a hose section (11) of the hose (7) to be cut arranged in the cutting plane (6) is guided tangentially past the axis of rotation (18) of the cutting disc (14) when cutting.

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