MX2008003452A - Monitoring system for fastener placing tool - Google Patents

Abstract

A fastener placing tool (11) for placing fasteners of the breakstem blind rivet type incorporates a force/stroke monitoring device (22) which comprises an assembly body (24) detachably mounted on the tool between the latter and the anvil (18) , a load-cell sensor (33) carried by the assembly body (24) for sensing the force applied by the hydraulic piston (16) to the jaw assembly 17 with respect to the anvil (18) , and a non- contact stroke- sensor (35) carried by the assembly body (24) for sensing the position of the jaw assembly (17) relative to the anvil (18) . The stroke-sensor (35) operates without physical contact with the jaw assembly (17) or any part of the tool moving therewith. To this end the jaw assembly (17) is connected to the hydraulic piston (16) by means of an adaptor tube (23) which has a conical tapering outer surface. The clearance distance between the sensor (35) and the adjacent part of the conical surface of the adaptor tube 23 varies with the axial position of the adaptor (23) and jaw assembly (17) .

Description

CLOSURE PLACEMENT TOOL MONITORING SYSTEM The invention relates to a monitoring system for a fastening positioning tool, and more specifically to a force / shock monitoring system for a tool for attaching snap fasteners. In summary, said fastener comprises a deformable substantially cylindrical metal cover containing within its hole a stronger metal mandrel, the mandrel comprising a rod with a radially elongated head at one end and adjacent one end of the cover, the other end (the final end) of the mandrel protruding from the other end of the cover. Such fasteners are well known to those skilled in the art and are widely commercially available under the Registered Trademarks AVEX, M0N0B0LT, HEMLOK and AVDELOK. As is well known, a suitable positioning tool comprises a nose piece for contacting the aforementioned other end of the clamp cover and the clamping means of the mandrel for clamping the aforementioned projecting end end of the mandrel. When a fastener is inserted into a suitable opening in a workpiece comprising two or more members that will be edged together, the placement tool is offered up to the fastener so that said end end of the mandrel enters the fastening means and the tool nose piece comes into contact with the end of the cover. The tool is operated to remove the clamping means from the nose piece, the clamping means clamps the mandrel and progressively applies the increasing tension to which with respect to the cover, the reaction force on the cover being supported by the nose piece of the tool. This causes the mandrel to move progressively with respect to the cover, so that the head of the mandrel enters the cover and causes the latter to expand radially beyond the remote face of the workpiece and the nosepiece of the mandrel. tool for radially expanding the end of the cover with which it is in contact, thereby holding the parts of the workpiece together. Increasing the tension eventually causes the mandrel to break into a weakened part (a rupture neck) at a predetermined proper position in its length. The tool is operated by a hydropneumatic system. Said tools and their manner of operation and use are well known to those skilled in the art. An example of such a tool is commercially available as a family under the Registered Trade Mark GENESIS.

In practice, it is convenient to ensure that said tool is performed correctly and optimally. The present invention is intended to provide a system that allows this to be done, making it possible to monitor the variation of the force applied by the tool to the fastener progressively as the tool collision (i.e., the movement of the chuck holding means). in relation to the nose piece) it progresses during the placement of a fastener. The invention provides in one of its aspects, a monitoring device according to the attached Claim 1. Further preferred features according to Claims 2, 6, and 8. The invention also provides, in another of its spectra, a fastener positioning tool according to Claim 3. Additional preferred aspects according to Claims 4 , 5, 6 and 9. A specific embodiment of the invention will now be described as the example and with reference to the accompanying drawings, in which: Figure 1 is an external lateral elevation of a fastener placing tool incorporating a device monitoring; Figure 2 is an axial section through the assembly body of the monitoring device before it is adapted to the tool; Figure 3 is an extreme elevation taken in the direction of arrow III in Figure 2, some parts being shown shaded; Figure 4 is an axial section through the monitoring device and the adjacent parts of the tool, which are illustrated in the form developed in the way they are assembled together; Figure 5 is a similar axial section through the assembled arrangement, and Figure 6 is an illustrative example of a force versus impact graph. The fastener placement tool of this example is commercially available under the Genesis model G4HD design. Its shape, construction and general method of operation and use (apart from the monitoring device) are well known. In summary, with reference to Figure 1, the tool 11 is held manually by means of a gun holder 12 surrounding the hydraulic cylinder of a pneumatic / hydraulic intensifier, which is supplied with air under pressure through a hose 13. Above the gun holder there is an actuator 14, depression of which actuates the operation of the tool by opening a air valve 15 (Figures 4 and 5) to supply compressed air to the pneumatic / hydraulic intensifier. This causes the application of hydraulic fluid under pressure to a hydraulic cylinder containing a hydraulic piston 16, the front end of which is connected to the mandrel holding means provided by the toothed assembly 17. The piston 16 and piston assembly 17 are they move along an axis 20. The tool includes cover contact means for contacting the cover of a fastener to be placed, in the shape of an anvil 18 at the front end of a tubular nose piece 19, within of which the toothed assembly 17 moves coaxially. In the normal tool without the monitoring device, the rear part of the nose piece is threadedly secured directly to the front end 21 of the tool body and the toothed assembly is threadedly secured directly to the front end of the hydraulic piston 16. In this example, The monitoring device comprises a monitoring assembly 22 that fits between the tool body 21 and the nose piece 19, and a substantially tubular piston adapter 23 that fits between the hydraulic piston 16 and the toothed assembly 17. To adapt the device to the tool, mainly the nose piece 19 and the toothed assembly 17 are removed (unscrewed) from the tool body 21 and the piston 16 hydraulic, respectively. Referring to Figure 4, the piston adapter 23 is secured at its rear end to the front of the piston 16, and the toothed assembly is secured to the front end of the piston adapter 23. The monitoring assembly 22 includes a body 24 and a back cover 25 (not shown in Figure 4, for illustration clarity). The body 24 is secured to the front end 21 of the tool body by screwing its rear projection threaded portion 26 into the front end 21 of the tool body, where it is secured by means of a locking wrench 27, after the assembly monitor 22 has been properly aligned circumferentially about its axis 20. The relative axial position of the toothed assembly 17 with respect to the nose piece 18 is the same as in the original tool. Referring to Figures 2 and 3, the monitoring assembly body comprises a front portion 28 and a rear bearing 29 of which the latter extends from the threaded portion 26. These two portions 28 and 29 are secured together by three screws 31, and separated by two washers 32 (around the two lower screws in Figure 3) and a load cell sensor 33 around the third screw 31. This captures the compressive force between the two parts 28 and 29 of the body 24, and therefore the compression load between the nose piece of the tool 19 and the tool leather 21. When the tool is in use by placing a fastener, this compression load is derived from the tension applied to the fastener by the nose assembly 17. Therefore, in use of the tool, the cell sensor load 33 captures the force applied to the fastener by the tool. The signal output from the load cell 33 is fed along a cable 34. The sensor assembly body 24 also carries the contactless contact sensor in the form of an analog inductive position sensor 35. As illustrated in Figures 4 and 5, the piston adapter 23 has part of its tapered outer surface, and more specifically in the form of a cone 36 that is coaxial about the axis 20. This extends so that, in use of the tool, the conical surface 36 passes through. adjacent to the shock sensor 35. The shock sensor 35 captures the distance between the end of the shock sensor and the part adjacent to the conical surface 36, whose distance will vary linearly with respect to the distance at which the adapter has been retracted. Since the surface 36 is conical about the axis 20, the rotational position of the adapter about the axis does not differentiate its radial distance, thus making it easier to assemble the adapter in the tool. The output of the shock sensor 35 is transported along a cable 37. The sensor body 35 is secured inside a sleeve 38 which engages threaded in a threaded hole 39 (FIG. 2) in the rear body part 29, presumed to be secured by means of a locking ring 41. Before adapting the monitoring assembly 22 to the tool as described above, the sensor at a time, the tapered tapered surface 36 of the adapter 23 will be heat-shrunk. After adapting the parts together as described above, with the toothed assembly 17 and the adapter 23 in their normal forward position (not activated), the position of the shock sensor 35 is adjusted until it captures a gap of 0.5 millimeters from the conical surface 36, and then closed in position by the locking ring 41. In use of the tool, as the toothed assembly 17 moves backward during the placement of a fastener, the spacing captured by the sensor 35 increases linearly in relation to the distance moved by the toothed assembly. The outputs of the force sensor 33 and the shock sensor 35 are fed along the cables 34 and 37 to a monitoring device 42, illustrated schematically in Figure 1. This interprets the output signals of the force and the sensors of strokes, and provides resulting inputs to a display device such as a visual display screen 43. This provides an equal display of force and shock values as they progress during the operation of the tool 11 to place a fastener, in form of a graph of value of blows against force value, whose visual screen is maintained until the beginning of the next operation of the tool. An example of such a graph is illustrated in Figure 6. The strike distance in millimeters is shown along the horizontal axis and the force in KiloNe tons is shown along the vertical axis. The shape of the graph will depend on a number of factors, such as the design, size and fastener material being placed by the tool and any variation in the tool's operating progress due to such things as it is used in its moving parts . The observation of the graph can indicate, for example, if a fastener has indeed been placed by the operation of the tool, and if so, how the tool works. The signal processing equipment within the monitoring device 42 requires some form of start and stop signals to drive and complete its process cycle for each use that the tool places an additional fastener. The use of the operation of the tool driver 14 may be preferred for this purpose. In this example, the tool is provided with a trigger operation sensor 44 (Figures 4 and 5). This is adjusted and arranged so that it only gives an output when the actuator has been depressed enough to start the operation of the tool. The trigger sensor is fed along a cable 45 to the monitoring unit 42, to operate its operation as mentioned before. The drive sensor 44, like the force and force sensors, can be easily separated, and separated, from the normal tool. The invention is not restricted to the details of the previous example.

Claims (9)

1. - A monitoring device for use with a fastener positioning tool for placing fasteners of the type comprising a cover and a mandrel to which the relative force is progressively increased is applied to progressively move the relative positions of the mandrel and cover to deform thus the cover, whose tool comprises cover contact means for contacting the cover, mandrel holding means for holding the mandrel and force applying means for applying a progressively increasing force to the mandrel holding means with respect to the cover contact means, so as to progressively move the mandrel relative to the cover; said monitoring device comprises: an assembly body that can be connected to the tool between the means for applying the force and the covering contact means; a force sensor carried by the body of the assembly to capture the force applied by the means for applying forces to the mandrel holding means with respect to the cover support means; and a non-contact shock sensor rotated by the body of the assembly to capture the position of the means of chuck clamping relative to the cover contact means, the shock sensor operating without physical contact with the chuck clamping means or any part of the tool or assembly moving therewith.

2. - A monitoring device according to claim 1, the device includes an adapter that can be connected to the mandrel holding means to move with them, the adapter including a tapering or tilted face that moves beyond the shock sensor so that the distance between the shock sensor and the adjacent part of the taper or inclined face varies as the mandrel holder means moves and is picked up by the shock sensor.

3. A fastening positioning tool for placing fasteners of the type comprising a cover and a mandrel to which relatively increasing force is applied in a progressive manner to progressively move the relative positions of the mandrel and cover to deform the cover, said tool comprises cover contact means for contacting the cover, mandrel holding means for clamping the mandrel, and force application means for applying progressively increasing force to the mandrel holding means with respect to the cover contact means , so as to progressively move the mandrel relative to the cover; the fastener placing tool incorporating a monitoring device comprising: an assembly body removably mounted on the tool between the means for applying force and the cover contact means; a force sensor carried by the body of the assembly to capture the applied force at least to apply force to the mandrel holding means with respect to the cover support means; and a non-contact shock sensor carried by the body of the assembly to capture the position of the mandrel holding means relative to the cover contact means, the shock sensor operating without physical contact with the mandrel holding means or any part of the tool or assembly moving with them.

4. A tool according to claim 3, said tool includes an adapter that is connected to the mandrel holding means for moving therewith, the adapter including a tapered or slanted face that moves beyond the shock sensor so that the distance between the shock sensor and the adjacent part of the tapered or inclined face varies as the mandrel holding means moves and is picked up by the shock sensor.

5. - A tool according to claim 4, in which the tapered or inclined face of the adapter has a conical shape.

6. A monitoring device according to claim 1 or 2, or a fastening positioning tool in any of claims 3 to 5, combining with a force / shock comparison device that is fed with information by the sensor of force and the shock sensor and produce a graph of the variation of the stroke with the variation of force.

7. A tool according to claim 6, in which the tool triggering mechanism is provided with a triggering operation sensor, which also supplies information to the out / strike comparison device, so as to drive the triggering device. comparison when the trigger is operated to drive the force application means.

8. A monitoring device substantially as described above with reference to, and as illustrated in, the accompanying drawings.

9. A fastening positioning tool substantially as described above with reference to, and illustrated in, the accompanying drawings.