Tightening method for a hydraulic connection and related tightening tool equipped with a hydraulic connection verification device

Abstract

Tightening tool equipped with a visual clamping condition device, comprising an elongated body (11) having a handle (12) at one end. On this body (11) there is an electronic processing block (14) containing electronic control circuits and an electronic processing unit. At the opposite end of the body having the handle, there is a seat (13) into which a plurality of inserts can be alternatively inserted, each insert is suitable for engaging the tool with a corresponding type and / or size of mechanical organ or element (screw, nut, etc.) on which the tool is intended to act. On this arm, there are sensor means suitable for detecting the tightening conditions exerted on this mechanical organ. Said visual device is controlled by this electronic processing unit and includes at least three light groups (21, 22, 23), which assume a plurality of on and off sequences describing the key tightening phases, in which each light group is able to take on at least two distinct colors, so that each color is associated with the information complete tightening or anomaly.

Description

[0001] Tightening method for a hydraulic connection and related tightening tool equipped with a hydraulic connection verification device

[0002] The present invention relates to an electronic tool for the controlled tightening of mechanical organs; this tool can be, for example, a torque wrench in which the tightening torque exerted on the bolt to be tightened can be controlled.

[0003] Tightening tools are known in the art, which comprise a body containing various control and, possibly, driving organs, to which one of several removable inserts is coupled, each of which is intended to engage a corresponding type of mechanical organ (e.g., the head of a screw, with male or female coupling) on which the tool is intended to act.

[0004] Electronic tools of this type comprise sensors, among which a torque sensor, to detect the torque exerted on the mechanical organ and other relevant parameters, so as to allow a controlled tightening of the mechanical organ through appropriate processing means which show various relevant parameters to the operator and, when necessary, command the tightening operation.

[0005] Patent EP2326464 describes a tool of this type in the form of a torque wrench, which comprises a body containing the control circuits and processing units of the wrench, a handle on one side (advantageously containing rechargeable batteries to power the wrench), and an arm on the other side. The body advantageously has a display for displaying operational information and data and a keyboard which allows to insert data and commands. A tool head which must be coupled with the type of mechanical organ (e.g., the head of a screw, with male or female coupling) on which the wrench is intended to act is interchangeably inserted into a dedicated seat at the end of the arm. The sensors that measure the torque to be exerted on the organ to be tightened are placed on the arm and comprise at least one strain gauge, which is a sensor whose electrical resistance changes based on the deformation it undergoes; it thus converts force, pressure, tension, weight, etc., into a change in electrical resistance that can be measured.

[0006] The value of the torque exerted is typically available on the wrench display or indicated near it using specific light and / or acoustic signals.

[0007] Patent EP4076846 describes a torque wrench equipped with a visual clamping condition device, controlled by a wrench electronic processing unit. This device comprises an annular support linked to the wrench, e.g., the arm, to which a plurality of light groups are associated, being arranged in a circular arc along the ring and are composed each of equidistant light points along the ring. These points are suitable for lighting up progressively when the tightening is completed.

[0008] These types of electronic wrenches can adopt tightening control strategies based on parameters different from each other. For example, it is possible to set a tightening strategy by controlling only the tightening torque and optionally monitoring the tightening angle. Or a tightening strategy can be set by controlling both the tightening torque and the tightening angle.

[0009] For all the strategies, however, it is important to monitor the progression of the tightening for these parameters.

[0010] Furthermore, for each of these strategies, different information must be effectively communicated to the operator during the different tightening phases for a controlled tightening operation.

[0011] Another type of wrench is the so-called mechatronic wrench, which is a tightening tool which comprises a mechanical part and an electronic part. The mechanical part is represented by the click mechanism that ensures the desired tightening is reached using the "click signal”.

[0012] Specifically, this mechanical torque detection mechanism provides the operator with the operation sensation of a force being applied which is suddenly reduced when the tightening torque has reached the set / desired torque value. The electronic part monitors the tightening torque and / or the tightening angle. An example of this type of wrench is provided in Patent EP3372344.

[0013] For the purposes of the present invention, hydraulic connection means the connection between two conduits with the interposition of an “O-ring” type seal, whose function is suitable for ensuring hydraulic seal between the conduits themselves.

[0014] Typical applications for such connection types are conduits in tractors and trucks, in which high-pressure fluid flows in the conduits.

[0015] In general, reference can also be made to links of pipes and hoses, and the fluids transported can be either liquids or gases. For hydraulic links (hydraulic oils), the pressures are generally significantly higher than those of gases (e.g., air).

[0016] These links are tightened using manual torque wrenches. It is also possible to use an electronic or mechatronic torque wrench. The hydraulic connection consists of a threaded connector with a flat flange and groove (space for the ring), an O-ring itself, and a fitting nut (drilled nut) with a flat flange. The correct tightening involves identifying all the necessary parts, comprising the O-ring, and tightening or compressing all the parts together.

[0017] A common source of leaking problems in these connections is just due to the presence of the O-ring seal.

[0018] Indeed, the most frequent problems arise from an O-ring that is incorrectly positioned (e.g., misaligned or stuck) or from its absence.

[0019] Even using a wrench in which the tightening torque is monitored and controlled through the presence of torque sensors (and possibly also angle sensors) is not able to ensure the actual seal by the O- ring.

[0020] The present invention uses the detection of the torque exerted during tightening to understand whether the O-ring seal is present and correctly positioned, thereby being able to ensure the required tightness of the hydraulic connection. Furthermore, during or at the end of tightening, the present invention provides a visual indication of whether the O-ring seal is correctly positioned or not, or absent.

[0021] One aspect of the present invention relates to a method for tightening a hydraulic connection having the features of claim 1.

[0022] A further aspect of the present invention relates to a tool for tightening a hydraulic connection provided with a hydraulic connection verification device having the features of claim 4.

[0023] Further objects and advantages of the present invention will be apparent from the following description and the attached drawings, provided solely by way of illustrative example and not limitation, in which:

[0024] Figures la, lb, and 1c illustrate three examples of elements for a hydraulic connection C, in which there are O-ring seals inserted into dedicated seats (Figure lb and 1c) or fitted onto a tubular element, as in Figure la.

[0025] Figure 2 is a perspective view of a tightening tool according to the present invention;

[0026] Figure 3 is an exemplary graph of the detections of the torque / angle sensors of the tool of Figure 2 for three tightenings,

[0027] Figure 4 illustrates a possible lighting sequence of the light groups of the verification device of the wrench of Figure 2.

[0028] Figure 5 is a front view of the tightening tool according to a further embodiment of the present invention.

[0029] In all cases, the hydraulic connection comprises a nut to be tightened using a tightening tool, and during the tightening of the nut, the O-ring seal is pressed into its seat, and being elastically deformable, it occupies all the spaces into the seat, creating the tightness.

[0030] The tightening tool according to the present invention comprises an elongated body 11 having a handle 12 at one end (preferably containing rechargeable batteries to power the wrench). On this body 11, in a substantially intermediate position, there is an electronic processing block 14 containing electronic control circuits and an electronic processing unit.

[0031] On this block, command buttons and electrical connection ports (e.g., USB, Ethernet, etc.) can be provided.

[0032] Using these ports or using a wireless connection, the wrench can be connected to external processing units. A wired connection can also be provided to provide an external power.

[0033] At the opposite end of the body having the handle, there is a seat 13 into which a plurality of inserts can be alternatively inserted. For example, each insert will be suitable for engaging the wrench with a corresponding type and / or size of mechanical organ or element (screw, nut, etc.) on which the tool is intended to act.

[0034] Although for simplicity, the inserts shown are all of similar size, elongated inserts or inserts with arms of particular shapes can also be provided, as known in the field.

[0035] The tool comprises sensor means (e.g., made with strain gauges arranged in the arm) for detecting the tightening conditions, such as for example sensors of the torque exerted on the mechanical organ and also a sensor (e.g., gyroscopic) for detecting the tightening angle.

[0036] The mechatronic wrench comprises therein a so-called "click" torque detection mechanism for torque wrenches, for example of the cam type having a cam and a roller brought into elastic contact using a spring.

[0037] According to one aspect of the present invention, the tool comprises a hydraulic connection verification device. Furthermore, using the tool of the present invention, a tightening method for a hydraulic connection of the type having an O-ring seal is made, in which during the tightening phase, it is checked whether there are anomalies or if the tightening is completed correctly.

[0038] For the purposes of the present invention, "correct tightening" means that the set target torque has been reached and that the Ciring seal is correctly inserted into the dedicated seat. Detected anomalies, on the other hand, can be the absence of the O-ring seal or an incorrect positioning of the O-ring seal itself.

[0039] The method according to the present invention comprises the phase of detecting the torque / angle curve using the tool sensors continuously during a normal phase of tightening the hydraulic connection. Still during tightening, a comparison is made between the detected torque and angle values, with a predefined (configurable) threshold value.

[0040] If this predefined threshold value corresponds to an angle lower than an initial tightening angle value, it means that the O-ring seal is absent, and the wrench verification device communicates an anomaly condition. This is because, without the interposition of the seal, the metallic parts being tightened against each other quickly come into contact, resulting in a sudden rise in the tightening torque for an even very small rotation of the wrench (a steeply rising curve on the graph - trace SI of Figure 3).

[0041] If this predefined threshold value corresponds to an angle between the initial tightening angle and a final tightening angle, it means that the O-ring seal is present, and the wrench verification device does not signal any anomalies, continues monitoring torque and angle until the target torque is reached and communicates the correct tightening condition. In fact, when the O-ring seal is present and in the correct position, the tightening torque rises very slowly during the initial phase of compressing the O-ring and changes slope when the O-ring is fully compressed and the two metallic parts of the connector come into contact. The "softer" part of the tightening is the flatter, initial portion of the curve, as illustrated by trace S2 in Figure 3).

[0042] If this predefined threshold value corresponds to an angle greater than this final tightening angle, it means that the O-ring seal is present but not correctly positioned, and the wrench verification device communicates an anomaly condition. This anomaly may also depend, in addition to the incorrect position, on the presence of an incorrect or damaged seal, resulting in a flat initial part of the more prolonged trace due to the compression of the seal, which gives more persistent "soft" features as the tightening angle increases. In all such cases, however, the target tightening torque is not reached, and the anomaly is signalled (trace S3 of Figure 3).

[0043] In the graph of Figure 3, the torque / angle curves SI, S2, and S3 are illustrated, referred to the same number of tightenings.

[0044] In this graph, a curve, when the tightening is correct, must reach the region CR delimited on the x-axis between the minimum or initial angle Am and the maximum or final tightening angle AM, and on the y-axis by the minimum Tm and maximum TM tightening torque.

[0045] The first tightening SI corresponds to a tightening in which the absence of the seal was found; in this graph, the threshold value V S is exceeded before reaching the minimum tightening angle Am.

[0046] The second tightening S2 corresponds to a tightening in which the presence of the correctly positioned seal was found; in this graph, the threshold value VS is exceeded between the minimum Am and maximum AM tightening angle. Tightening concludes when reaching the valid tightening region CR.

[0047] The third tightening S3 corresponds to a tightening in which an anomaly in the seal was found; in this graph, the threshold value VS is exceeded at an angle greater than the maximum tightening angle AM. Since the angle threshold is evaluated before reaching the target end tightening area CR, the anomaly related to the O-ring can be signalled before completing the tightening, making it easier to restore the hydraulic connection, avoiding, where possible, the replacement of parts that are no longer reusable due to tightening.

[0048] Therefore, in summary, the method according to the present invention comprises the following steps:

[0049] • During the tightening of a hydraulic connection to a pre- established target tightening torque, continuously detect the torque exerted and the rotation angle of the tool,

[0050] • Compare the detected torque with a threshold value (VS),

[0051] • If from the measurement this threshold value corresponds to a rotation angle lower than a minimum tightening angle (Am), issue a tightening anomaly signal,

[0052] • If from the measurement this threshold value corresponds to a rotation angle between a minimum tightening angle (Am) and a maximum tightening angle (AM), when the torque reaches the target value, issue a correct tightening signal,

[0053] • If from the measurement this threshold value corresponds to a rotation angle greater than a maximum tightening angle (AM), issue a tightening anomaly signal.

[0054] The signalling of the anomaly and that of correct tightening can be a visual and / or acoustic signal. The visual signal also comprises the signalling of intermediate tightening phases.

[0055] The verification device comprises at least three light groups 21, 22, and 23, which assume a plurality of on and off sequences describing the key tightening phases and signals possible tightening anomalies. Each light group is able to take on at least three distinct colors, so that each color is associated with the information complete tightening, tightening in progress, or incorrect tightening (error). To this end, each group is made up of RGB LEDs.

[0056] Preferably, each light group can assume the conditions of: • Turned off;

[0057] • Turned on in the progress tightening color;

[0058] • Flashing in the progress tightening color;

[0059] • Turned on in the complete tightening color;

[0060] • Turned on (flashing or solid) in the incorrect tightening or anomaly color.

[0061] These conditions define configurations for tightening in progress, complete tightening, and incorrect tightening or error.

[0062] Both the complete tightening configuration and the error configuration can be accompanied by a characteristic sound.

[0063] Preferably, the light groups are placed on the block 14 and comprise small rectangles placed side by side along the longitudinal axis of the body, as particularly visible in Figure 2.

[0064] The selection of colors for tightening in progress, complete tightening, and error corresponds to the common meaning of the colors itself.

[0065] Preferred colors for this purpose are green: correct tightening, red: error, and solid or flashing white: tightening in progress.

[0066] Within the scope of this invention, there is nothing to prevent the selection of other colors providing the same meaning. For example, white could be replaced with yellow, and so on. The flashing must be easily visible to the operator's eye, so a flashing frequency of about 1 Hz has been selected.

[0067] According to the present invention, the on and off sequence of the light groups provides that they are initially all turned off, during the intermediate tightening phases, the groups, starting from the first, from the right or from the left, and in succession one after the other, flash or light up in the progress tightening color until either the programmed tightening is reached, when they light up in the correct tightening color or until the anomaly is detected, when they light up in the error color.

[0068] According to the present invention there are a plurality of sequences for the intermediate tightening phases.

[0069] For example, in Figure 4, each group in succession, starting from the first on the right or left, first begins to flash and then is solidly lit. In the case where there are three groups, five (or six, if the phase with the three groups turned on in the progress color is also considered) on configurations are then defined, corresponding to the same number of intermediate tightening stages.

[0070] Thus, by varying the number of groups and the on configurations, more sequences can be created depending on the requirements.

[0071] Programming the tightening strategy (comprising tightening torque and angle control) and the various on sequences of the device groups is performed on the electronic processing unit of the electronic processing block 14.

[0072] The torque and angle sensors detect the tightening parameters and provide them to this processing unit, which turns the light groups on according to the programmed sequence.

[0073] If the wrench hosting the device of the present invention is a mechatronic wrench, thus also provided with a click mechanism, each sequence of turning the light groups on can be programmed so as to position the click event at a specific on configuration.

[0074] Indeed, the click mechanism is manually or electronically adjustable to a prefixed tightening torque, this click tightening torque can correspond to an on configuration expressing a prefixed intermediate percentage of tightening completion (e.g., 90% of the target). In this case, the processing unit is able to adopt the temporary drop in the detected torque after the click, maintaining the last configuration of turning the sequence on until the torque resumes rising beyond this prefixed percentage. Alternatively, the device of the present invention operates independently of the click mechanism. Still according to a further alternative, the preset tightening torque on the click mechanism corresponds to the complete tightening configuration (all groups turned on in the complete tightening color).

[0075] The present invention has the following advantages.

[0076] The operator performing the tightening is provided with a feedback almost in real time (not in post-processing). Thus, the operator itself can stop tightening before damaging the connection or the O-ring seal.

[0077] When the anomaly is signalled, the tightening is not yet complete, and the operator can open the connection not yet tightened. This ensures easy re-processing.

[0078] The positive result is signalled (green LEDs, a high-pitched acoustic signal such as an acoustic signal, vibration, or message on the display), and the operator can tighten the link without interruptions.

[0079] According to the present invention, the verification device comprises a projection light group 24 configured so as to project light in the direction of the tool head and thus the joint to be tightened. This projection group preferably assumes the same colors (thus the progress tightening, complete tightening, or error configurations) as the lighting groups 21, 22, and 23, so that the operator, even not looking at the wrench body direction, but focusing on the joint, is able to know the state of the progress or complete tightening.

[0080] This projection group 24 is preferably placed on the block 14 as the other groups but placed on the front part of the same, arranged on the part facing the tool head. This placement facilitates the projection of light toward the tool head.

Claims

CLAIMS1. Method for tightening a hydraulic type connection having an O-ring seal, using a tightening tool equipped with sensors for measuring the tightening torque exerted and the angle of rotation of the tool itself, including the following steps:• during the tightening of said hydraulic connection to a pre- established target tightening torque, continuously detect the torque exerted and the rotation angle of the tool,• compare the detected torque with a threshold value (VS),• if from the measurements for this threshold value corresponds a rotation angle lower than a minimum tightening angle (Am) issue a tightening anomaly signal,• if the measurements for this threshold value correspond to a rotation angle between a minimum tightening angle (Am) and a maximum tightening angle, when the torque reaches the target value emit a correct tightening signal,• if from the measurements for this threshold value corresponds a rotation angle greater than a maximum tightening angle (AM), issue a tightening anomaly signal.

2. Method according to claim 1 in which the signalling of the anomaly and that of correct tightening is a visual and / or acoustic signal.

3. Method according to claim 2, wherein the visual signalling also includes the signalling of intermediate tightening phases.

4. Tightening tool equipped with a visual clamping condition device comprising• an elongated body (11) having a handle (12) at one end,• on this body (11) there is an electronic processing block (14) containing electronic control circuits and an electronic processing unit,• at the opposite end of the body which has the handle there is a seat (13) into which a plurality of inserts can bealternatively inserted, each insert is suitable for engaging the tool with a corresponding type and / or size of mechanical organ or element (screw, nut, etc.) on which the tool is intended to act,• on this arm there are sensor means suitable for detecting the tightening conditions exerted on this mechanical organ, characterized in that said visual clamping condition device is controlled by this electronic processing unit and includes at least three light groups (21, 22, 23) which assume a plurality of on and off sequences describing the key tightening phases, in which each light group is able to take on at least two distinct colors, so that each color is associated with the information complete tightening or anomaly.

5. Tightening tool according to claim 4, wherein each light group also takes on at least a third color associated with progressing tightening phases.

6. Tightening tool of claim 5, wherein the assemblies when turned on in a progressing tightening configuration may flash or be solid.

7. Tightening tool according to claim 4, wherein the assemblies when in a full tightening configuration are all solidly lit, while in a fault configuration they are either solid or flashing.

8. Tightening tool according to claim 4, wherein each light group is made up of RGB LEDs.

9. Tightening tool according to claim 1, in which the light units are placed on the block (14) and are small rectangles placed side by side along the longitudinal axis of the body (11).

10. Tightening tool of claim 4, wherein the correct tightening color is green, the error color is red, and the progress tightening color is white.

11. Tightening according to claim 5, in which this sequence of turning the lighting groups on and off provides that beforetightening the groups are all turned off, during the intermediate tightening phases the groups starting from the first, from the right or from the left and in succession one after the other they flash or light up in the color of tightening in progress, until the programmed tightening is reached, when they light up in the color of correct tightening or the error color.

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