Setting tool for blind fasteners

Abstract

To provide a setting tool for blind fasteners.SOLUTION: A setting tool (10) for blind fasteners comprises: a first electric motor (36) with a first drive shaft, which is arranged in a first housing portion and is connected to a tool housing portion (26) via a first transmission; a tool shaft arranged in the tool housing portion (26) and connected to a screw tool, where the screw tool is rotationally and translationally movable along and around a longitudinal axis (X) between a retracted position and an extended position; a feeder (18) with a fastener delivery tube (66), the feeder (18) being for delivering the blind fastener into the tool housing portion (26) in front of the screw tool when the screw tool is in the retracted position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an installation tool for installing blind fasteners or blind elements into a workpiece. [Background technology]

[0002] In automotive manufacturing, typically various components such as strips, rails, fittings, etc. are fastened to thin-walled components, for example aluminum sheet metal or profiles. A common method of joining components is by using fasteners with threads.

[0003] A blind fastener is a fastening element that is to be placed into an opening, e.g., a through hole in a metal sheet or some other sheet or workpiece. Typically, blind fasteners are used to fasten multiple workpieces together when it is difficult or impossible to access one hidden side of the workpieces. Typically, blind fasteners include a sleeve or shank that expands or bends during assembly. A blind fastener can be a blind rivet, blind rivet nut, self-drilling self-tapping screw, or similar fastener. A blind fastener can include an internal thread, thereby allowing threaded connection to a metal sheet or workpiece where the wall thickness is not sufficient to realize a thread.

[0004] A blind fastener installation device or installation tool for blind fasteners is used to automatically install the blind fastener into an opening in a workpiece. In an undeformed state, the blind fastener has a hollow cylindrical rivet shank, one end of which is provided with a radially extending installation head and on the other end of which an internal thread is formed (e.g. for a blind rivet nut) and / or a mandrel can be located (e.g. for a blind rivet). To install the blind rivet nut in a hole, it is known to use a bolt having an external thread that cooperates with the internal thread of the blind rivet nut. The internal thread of the blind rivet nut engages with the external thread of the bolt.

[0005] The blind fastener is inserted into the hole first with the rivet shank until the rivet head contacts the sheet metal. Activation of the blind fastener installation device then causes the bolt or mandrel, and therefore the threaded area, to move axially back from the blind fastener and sheet metal, thereby causing compression of the rivet shank. A bead or bulge is formed on the workpiece side opposite the rivet head to the desired deformation point. The blind fastener is thus trapped in the hole (or opening).

[0006] To remove the installation device from the installed blind fastener, pressure on the bolt is released and rotated in the drill-off direction, after which the blind fastener installation device is available for a new installation operation.

[0007] For example, EP 0 886 733 discloses an installation device for a blind rivet nut, which comprises a first actuator configured to guide the blind rivet nut along its longitudinal axis and a second actuator configured to rotate the bolt or a threaded insert, in particular to remove the bolt from the blind rivet nut after the installation step (in other words after the blind rivet nut crimping).

[0008] For example, U.S. Patent No. 7,346,970 discloses an installation device for blind fasteners, which includes a single motor having a drive shaft positioned in a first housing part and coupled to a tool housing part via a power transmission means. The tool housing part is laterally offset relative to the drive shaft and extends parallel thereto. The tool shaft is disposed within the tool housing part and has a screw-type tool protruding from a front end of the tool housing part to which it is non-rotationally coupled. Locking means by which the tool housing part and the tool shaft can be coupled in a non-rotational manner, or separate anti-rotation means by which the tool shaft can be prevented from rotating or released for rotation, are also provided.

[0009] US Publication No. 2016114383 discloses a riveting device for attaching a blind rivet element, which includes a mandrel, a first motor with a first operative coupling with the mandrel, and a second motor with a second operative coupling with the mandrel. The mandrel has a rotational motion transmitted thereto for threading the mandrel into the blind rivet element, and is configured to be pulled back into the riveting device by a retraction movement to cause at least partial plastic deformation of the blind rivet element. The first motor transmits the rotational motion to the mandrel via the first operative coupling. The second motor transmits the retraction movement to the mandrel via the second operative coupling. Such a configuration may be heavy and not provide the required flexibility.

[0010] German Patent No. 3341602 discloses an apparatus for inserting threaded fasteners in order to radially expand them by contracting them, the apparatus being of the type including an anvil on which the fasteners are compressed by a threaded mandrel rotated by an air-driven motor. The apparatus does not allow for the automated installation of blind fasteners.

[0011] Such installation tools can be cumbersome and require a minimum amount of time to perform all the steps and movements required to perform the crimp and then be available for the next installation operation. Installation of blind fasteners is often cumbersome as multiple steps are required to capture and properly orient the blind fastener. Additionally, the forces and movements required to engage such blind fasteners often represent complex systems that cannot be compact in view of the forces required. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] European Patent No. 0886733 [Patent Document 2] U.S. Patent No. 7,346,970 [Patent Document 3] US Publication No. 2016114383 [Patent Document 4] German patent no. 3341602 Summary of the Invention [Problem to be solved by the invention]

[0013] It is therefore an object of the present invention to at least alleviate the above-mentioned disadvantages. More particularly, it is an object of the present invention to provide a blind fastener installation device that is simple in design, compact and reliable, and allows for high speed installation of blind fasteners to reduce production time. [Means for solving the problem]

[0014] For this purpose, according to the invention there is provided a blind fastener installation device as claimed in claim 1.

[0015] Such an installation tool can be fully automatic. The blind fastener delivery means can be directly integrated into the tool, reducing installation times and eliminating the need for additional delivery mechanisms. The presence of two motors allows precise control of the position and applied load during the installation process, and joining parameters can be precisely controlled and adapted to different blind fasteners or workpieces to be joined. The first, second and tool housing parts facilitate maintenance operations.

[0016] According to one embodiment, the tool housing part comprises a solid roller screw coupled to the tool shaft, a shaft gear having an anti-rotation sleeve is disposed around the solid roller screw, and the shaft gear is coupled to a second electric motor via a second housing gear.

[0017] According to one embodiment, a solid roller screw coupled to a tool shaft has a first end coupled to the tool shaft and a second end opposite the first end, and an anti-rotation hub of the solid roller screw is disposed on the second end.

[0018] According to one embodiment, the second housing part comprises a second electric motor having a second drive shaft and a second housing gear, and the first housing part comprises a first electric motor and a first housing gear, the first housing gear being coupled to a tool gear that is fixedly coupled to a roller screw nut disposed within the tool housing part and disposed around the solid roller screw.

[0019] According to one embodiment, the rotation of the first drive shaft results in a linear motion of the solid roller screw. The first transmission device, when controlled alone, results in a translation of the solid roller screw and thus of the tool shaft and the screw tool.

[0020] According to one embodiment, rotation of the first and second drive shafts at different rotational speeds results in linear and rotational movement of the screw tool, such that the screw tool can engage the blind fastener. Both motors work together to enable translation and rotation of the screw tool. This configuration ensures a tight coupling and precisely controlled response of the screw tool by both motors. Load and installation forces can be controlled by the two motors.

[0021] According to one embodiment, the delivery tube runs parallel or substantially parallel to the tool housing part, the joint path comprises a first portion coaxial with the delivery tube and a portion aligned with the longitudinal axis, the joint path being configured to deliver the blind fastener into the tool housing part, thus making the tool compact and adapted to be used in an industrial environment.

[0022] According to one embodiment, a clamping device is provided that is configured to clamp the blind fastener for engagement with a screw tool, the clamping device being disposed within the tool housing portion. The clamping device holds the nut within the tool housing portion such that engagement with the screw tool is achieved within the installation tool in a straight line, which reduces installation time.

[0023] According to one embodiment, the clamping device comprises two movable jaws adapted for clamping blind fasteners. The two movable jaws allow for centered or eccentric clamping and, if necessary, adaptation of the clamping force to the nut. In addition, eccentric clamping allows good clamping of nuts with, for example, hexagonal shanks. The movable jaws are force-actuated.

[0024] According to one embodiment, the clamping device further comprises a retaining lever, such that the blind fastener is retained within the clamping device during clamping by the jaws, the lever acting as a gate to keep the nut within the clamping device so that the jaws can be actuated.

[0025] According to one embodiment, each of the jaws comprises a capture surface having a first and a second segment, the first segment being aligned relative to the second segment, the first segment being flat and the second segment comprising a bulge configured to provide an asymmetric shape to properly orient the blind element within the clamping device.

[0026] According to one embodiment, the screw tool comprises an anvil sleeve configured to contact the movable jaw.

[0027] According to one embodiment, the tool shaft comprises a front segment and a rear segment, a middle segment is disposed between the front and rear segments, and the front segment comprises a first portion coupled to the flange via a groove.

[0028] According to one embodiment, the flange includes a plurality of evenly distributed holes configured to receive the jackbolts, and the groove has a multi radii curvature.

[0029] The present invention also relates to a method for installing a blind fastener into a workpiece, - providing a blind fastener installation device as described above; - providing a blind fastener comprising a rivet shank having an internal thread and a rivet head; - feeding a blind fastener to a feed assembly such that the blind fastener moves through a feed path into a retainer; - holding the blind fastener in a retainer such that the blind fastener is in a loaded position; - guiding a screw tool into a blind fastener having a shank in a first direction along a longitudinal axis by means of the first and second transmission devices to engage with an internal thread of the blind fastener; - ejecting the blind fastener from the tool housing portion into the nose portion and further guiding the blind fastener in a first direction along the longitudinal axis out of the nose portion; - guiding the blind fastener through a hole in the workpiece until the head contacts the workpiece and at least a portion of the shank extends into the hole; - deforming the blind fastener by displacement by a first transmission device in a second direction opposite to the first direction in order to perform a crimping process of the blind fastener; - guiding the screw tool in a second direction along the longitudinal axis by means of the first and second transmission devices in order to remove the blind fastener from the screw tool; Includes.

[0030] Such a method is easy to implement and allows for good installation control with short installation times. In one embodiment, a torque test can be performed to check the quality of the crimp and / or the quality of the female thread after crimping.

[0031] According to one embodiment, the torque of the roller screw is monitored and unexpected torque peaks are avoided by shutting down the first motor (36) and disengaging the second motor.

[0032] Other characteristics and advantages of the present invention will become readily apparent from the following description of embodiments, given as non-limiting examples, with reference to the attached drawings, in which: [Brief description of the drawings]

[0033] [Figure 1] FIG. 2 is a schematic perspective view of an installation tool for a blind fastener. [Figure 2A] 1 is a schematic cross-section of a first transmission assembly and a feeder of an installation tool in a first position according to the present invention. [Figure 2B] 1 is a schematic cross-section of a second transmission assembly and a feeder of an installation tool in a first position according to the present invention. [Figure 3A] 1 is a schematic cross-section of a first transmission assembly and a feeder of an installation tool in a second position according to the present invention. [Figure 3B] 1 is a schematic cross-section of a second transmission assembly and a feeder of an installation tool in a second position according to the present invention. [Figure 4] FIG. 2 is a front perspective view of a tool housing portion of an installation tool according to the present invention. [Figure 5A] 1 illustrates a clamping device on a tool housing part having a retaining tongue according to one embodiment. [Figure 5B] 1 illustrates a clamping device on a tool housing part having a retaining tongue according to one embodiment. [Figure 5C] 1 illustrates a clamping device on a tool housing part having a retaining tongue according to one embodiment. [Figure 6A] FIG. 13 shows a clamping device according to another embodiment, provided on a tool housing part having a holding lever; [Figure 6B] FIG. 13 shows a clamping device according to another embodiment, provided on a tool housing part with a holding lever; [Figure 6C] FIG. 13 shows a clamping device according to another embodiment, provided on a tool housing part with a holding lever; [Figure 7A] FIG. 6D is a detailed view of the clamping device of FIGS. 6A to 6C in a first position. [Figure 7B] FIG. 6D is a detailed view of the clamping device of FIGS. 6A to 6C in a second position. [Figure 8A] FIG. 5C is a detailed view of the clamping device of FIGS. 5A to 5C with a blind fastener in a first position. [Figure 8B] FIG. 5C is a detailed view of the clamping device of FIGS. 5A to 5C with the blind fastener in a second position. [Figure 8C] FIG. 5C is a detailed view of the clamping device of FIGS. 5A to 5C with the blind fastener in a third position. [Figure 9A] FIG. 5C is a detailed view of the retention tongue of FIGS. 5A and 5B. [Figure 9B] FIG. 5C is a detailed view of the retention tongue of FIGS. 5A and 5B. [Figure 10A] 1 is a cross-sectional view of a front portion of a tool housing portion movably coupled to a nose portion in a first position according to one embodiment; FIG. [Figure 10B] FIG. 10B is a cross-sectional view of a front portion of the tool housing portion movably coupled to the nose portion in a second position according to the embodiment of FIG. 10A. [Figure 11] FIG. 2 is a detailed view of the tool shaft of an installation tool for a blind fastener. [Figure 12] FIG. 12 is a detailed top view of the head of the tool shaft of FIG. [Figure 13] FIG. 12 is a side view of the head of the tool shaft of FIG. [Figure 14A] 13A-B show schematic diagrams of torque, speed and angle recorded during the installation steps of the first motor while the second motor is held in place. [Figure 14B] 13 shows the torque, speed and angle recorded during the installation step of the first motor with the second movement strategy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] In the various drawings, the same reference signs represent identical or similar elements.

[0035] 1 generally illustrates an installation tool 10 for a blind fastener or blind element. As illustrated, the installation tool 10 includes a housing 12 having various housing portions, a tool nose 14, and a feeder 18 configured to drive a blind fastener 20 to the tool nose 14 to perform a crimping step.

[0036] The housing 12 is configured to be attached to an arm of a robot via a joint 24. In an embodiment, the housing 12 is fixed to a support via a slide configured to translate the housing 12. The slide can be actuated by an actuator.

[0037] Typically, the blind fastener or blind element or blind rivet nut 20 may include a hollow rivet shank 22 having an internal thread and a rivet head 24 extending outwardly from the rivet shank at one end of the shank. The rivet shank 24 is configured to be placed into a hole in a workpiece and the rivet head is configured to contact a surface of the workpiece. The rivet shank 22 is configured to be deformed by a setting tool to force the formation of a crimp bulge on the underside of the workpiece.

[0038] As shown in FIGS. 2 and 3, the housing 12 includes a tool housing portion 26, a first housing portion 28, and a second housing portion 30. As shown in FIG.

[0039] Power transmission The tool housing part 26 comprises a tool shaft 32 coupled to a screw tool 34, the screw tool 34 being adapted to engage with the internal threads of the blind fastener 20. The tool shaft 32 and the tool screw 34 are rotatable and translatable via first and second transmissions which cooperate with first and second electric motors 36, 38, respectively. The tool shaft 32 and the tool screw 34 are rotatable and translatable along and about a longitudinal axis X. The tool housing part 26 further comprises a solid roller screw 40 coupled to the tool shaft 32, more particularly fixedly assembled thereto, such that a rotational or translational movement of the solid roller screw 40 can be transmitted to the tool shaft 32. A washer is arranged between the roller screw and the tool shaft.

[0040] The anvil sleeve 140 can be provided around the screw tool and can move elastically along the screw tool, and the tool sleeve 150 can be disposed around the screw tool and can provide a gap G between the anvil sleeve and the tool sleeve.

[0041] The tool shaft 32 is shown in more detail in Figures 11, 12 and 13. As shown in Figure 11, the tool shaft 32 is a jackbolt designed to reduce stress loads in the rods and tie bars. This design of the tool shaft 32 allows it to withstand particularly high cycle fatigue with a compact element designed to be located in a restricted area where more material cannot be used to support the load. Thus, the tool shaft 32 of the present invention is particularly compact. The tool shaft comprises a front segment 100 and a rear segment 102. An intermediate segment 104 is located between the front and rear segments 100, 102. The tool shaft 32 is a longitudinally extending, predominantly cylindrical element.

[0042] The front segment comprises a first portion 106 defining a free end and a flange 108 connected to the first portion. The first portion is threaded. For example, the thread is M16*0.5, the same as the roller screw. The front segment is shown in more detail in FIG. 13. The first portion 106 is cylindrical and has a constant cross section. The cross section is, for example, 15.2 mm. The first portion extends in the longitudinal direction and comprises a chamfer at the free end. For example, the chamfer can be 45°. The first portion 106 connects to the flange via a groove 110. The groove 110 can be realized with multiple radii, and the connection between the flange 108 and the first portion 106 allows for a better redistribution of forces in the case of high loads on the tool shaft 32. For example, the groove has a first radius of 2.5 mm near the first portion 106, which increases to a radius of 3 mm before decreasing to 1 mm near the flange 108. In other words, the groove is designed with a series of radii linked with a tangential profile. The particular dimensions and curvatures of the groove allow an appropriate redistribution of forces on the tool of the invention. The flange 108 comprises a section with a constant circular cross section. The cross section of the flange 108 is larger than the cross section of the first part 106. A number of holes 112 arranged to receive screws (more specifically jack bolts or compression jack bolts) for fastening are regularly arranged on the flange (see FIG. 12). For example, ten identical holes are arranged on the flange at 36° from each other. This number of holes is particularly advantageous because it allows prestressing. The prestress is evenly distributed around the periphery of the flange. A large number of jack bolts allows prestressing without high torques. Prestressing is necessary to ensure that the joint formed on the tool shaft remains firmly joined and to optimize the service life. In case of an external load, the compressive prestress will be balanced away from the joint, so that the additional stresses are reduced to a minimum. This transition allows for maximum material around the threaded holes, which helps to take up, distribute and subsequently reduce the high stresses from the jackbolt.The gradual transition from the thick-walled diameter to the thin-walled diameter serves to optimally distribute the stresses that occur. Such a design allows a long service life while keeping the tool compact, so that in particular the tool shaft has a maximum diameter of 30 mm. The flange 108 has an upper face 114 facing the first part 106 and a lower face 116 facing the intermediate segment 104. A washer is arranged in contact with the upper face 114. The washer is made of a hardened material and forms the joint between the tool shaft 32 and the roller screw 40. As can be seen in FIG. 13, the lower face has a curvature. The radius of curvature can be 7 mm. For example, the lower face forms an angle of 60° with the outer face of the flange.

[0043] The intermediate segment 104 has a constant cross section. For example, the diameter of the intermediate section is 13.5 mm. The intermediate section extends in the longitudinal direction and may be provided with a passage on part of its longitudinal length. A passage opening 118 is visible on the side of the intermediate segment. A groove 120 is provided between the intermediate segment 104 and the rear segment. The rear segment 102 comprises three parts, each of which has a different diameter and a constant cross section. More precisely, the diameter of each part decreases, such that the part at the free end of the rear segment has the smallest diameter. A second opening of the passage is provided in the intermediate part of the rear segment 102.

[0044] The design of the tool shaft therefore allows for a compact element (with a maximum diameter of 30 mm) configured to support an external load of up to 35 kilonewtons.

[0045] The solid roller screw 40 has a first end 42 configured to be secured to a tool shaft and a second end 44 opposite the first end. The tool shaft 32 and screw tool 34 may be part of a load pin assembly.

[0046] A solid roller screw anti-rotation hub 46 may be disposed at the second end 44. The solid roller screw 40 comprises a first segment near the second end 44 and a second segment near the first end 42. A shaft gear 48 with an anti-rotation sleeve is disposed around the first segment of the solid roller screw 40. A roller screw nut 50 is disposed around the second segment of the solid roller screw 40 and interacts with the solid roller screw. A tool gear 52 is fixedly coupled to the roller screw nut 50. The tool housing part 26 may also comprise a load cell 54 configured to determine the load applied to the blind fastener 20 during the installation step (or, more particularly, during the crimping step). The load cell provides a compressive force. Thus, the load cell 54 allows reading the load applied to install the nut during crimping. If a predetermined load is reached, the crimping is performed properly and the motor can then be stopped.

[0047] The first housing portion 28 includes a first electric motor 36 having a first drive shaft 56 and a first housing gear 58 coupled to the first drive shaft 56 .

[0048] The second housing part 30 comprises a second electric motor 38 having a second drive shaft 60 coupled to a second housing gear 62. The first housing part 28 may extend longitudinally in a direction parallel to a longitudinal direction of the second housing part 30 and / or the tool housing part 26. The second housing part 30 may extend longitudinally in a direction parallel to a longitudinal direction of the tool housing part. More particularly, the tool housing part 26 may extend longitudinally about a longitudinal axis X, with the first and second housing parts extending longitudinally notably parallel to the longitudinal axis X.

[0049] The first transmission device comprises a first housing gear 58, a tool gear 52, and a roller screw nut 50. The first electric motor 36 is configured to rotate a first drive shaft 56, which rotates the first housing gear 58 interacting with the tool gear 52. The first motor 36 causes linear motion as long as the second motor 38 holds its position. For example, the maximum speed of the first motor is 70 mm / s. In one embodiment (not shown), a joint gear can be provided in the second housing part and can be coupled to the first housing gear. The joint gear can interact with the housing gear and the tool gear.

[0050] The second transmission device comprises a second housing gear 62 and a shaft gear 48 with an anti-rotation sleeve. Rotation of the second drive shaft 60 causes rotation of the second housing gear 62 which interacts with the shaft gear 48, allowing the shaft gear 48 to translate and rotate. The shaft gear 48 transmits motion to the solid roller screw 40. In other words, the second motor 38 causes linear and rotary motion. For example, the maximum speed is 78 mm / s.

[0051] When both motors (first electric motor 36 and second electric motor 38) rotate at different predetermined speeds (more specifically, when the first drive shaft and the second drive shaft rotate at different predetermined speeds), the solid roller screw 40 is driven with translational and rotational motions. The solid roller screw 40 can thus transmit translational and rotational motions to a screw tool that can engage with the female threads of the blind fastener. For example, the screw tool can translate in a first direction and in a second direction opposite to the first direction. Also, the screw tool 34 can rotate in a first rotational direction and in a second rotational direction.

[0052] When the second electric motor 38 (or, more specifically, the second drive shaft) is prevented from rotating and the first electric motor 36 (or, the first drive shaft) rotates, linear motion of the solid roller screw is induced. The linear motion can be in a first direction or a second direction opposite to the first direction.

[0053] Feeder The feeder comprises a fastener delivery tube 66 and a blind fastener supply source (not shown), the delivery tube 66 for delivering the blind fasteners to the tool housing portion 26 being connected at a first end to the blind fastener supply source and at a second end to the tool housing portion 26. The separated blind fasteners 20 are delivered directly into the tool housing portion 26 in front of the screw tool 34 so that the installation step can be performed directly.

[0054] The delivery tube 66 can extend parallel or substantially parallel to the tool housing part 26. The delivery tube 66 is coupled to the tool housing part 26 via a receiving assembly 68 that includes a mating passage 70 that directly connects the delivery tube 66 to the tool housing part 26 so that the screw tool 40 can engage the blind fastener 20 within the tool housing part 26. The mating passage 70 includes a first portion 72 coaxial with the delivery tube 66 and a portion 74 coaxial with the longitudinal axis, such that the mating passage 70 is configured to deliver the blind fastener into the tool housing part and coaxially to the screw tool 34. A cover is used to close the mating passage 70.

[0055] The receiving assembly 68, and more particularly the joining path, is provided with a stop feature, particularly in its first portion. A gate or lever is disposed in the joining path and configured to slow down the blind fastener 20 before it reaches the tool housing portion. The gate or lever is disposed in particular in the first portion. This gate or lever stops the blind fastener in the first portion until a signal is sent that an installation step is required and no other blind fasteners are present in the tool housing portion. The gate or lever also prevents the blind fastener from undesirably dropping into the tool housing portion.

[0056] As shown in Figures 4, 5A, 5B, and 5C, a clamping device 76 is provided which is configured to clamp the blind fastener 20 prior to engagement with the screw tool. The clamping device 76 is disposed within the receiving assembly 68, and more particularly within the portion of the joint path coaxial with the screw tool.

[0057] As shown in Figures 5A, 5B, 5C and 8A-8C, which represent a preferred embodiment, the clamping device 76 comprises two jaws 78 movable between an open position and a clamped position. The jaws 78 can be identical or symmetrical. Each jaw can comprise a curved portion configured to clamp against a blind fastener, more specifically against a shank of the blind fastener. As shown in Figures 8A-8C, each jaw has a contour formed by two segments. The two segments are angled with respect to each other. Both segments are significantly flat, but on one of the segments a protrusion is provided. The protrusion of the first jaw can be opposite the protrusion of the second jaw. Such a design is particularly advantageous for hexagonal blind fasteners (in other words, blind elements with hexagonal shanks). In fact, the asymmetric prismatic shape supports the blind fastener to rotate before clamping and prevents the closure of the prismatic surface on the edge of the hexagonal shank of the blind element. The jaws 78 slide to apply a retention force to the blind fastener. For example, the jaws are driven by an actuator that controls the open and closed position of jaw 78. The arrows in Figures 8A-8C show the movement of the jaws and how the blind elements can rotate to reach a final stable position.

[0058] In one embodiment shown in Figures 7A and 7B, the jaws 78 may be eccentric with respect to the midline axis of the blind fastener's shank, with one jaw gripping the shank above the midline axis and the other jaw gripping the shank below the midline axis. In Figure 8A, the jaws 78 are open. In Figure 8C, the jaws 78 are closed and the blind fastener is aligned along the longitudinal axis X. The jaws 78 may be positioned to create an eccentric clamping motion. Thus, the blind fastener 20 may conform to the contours of the jaws 78 and slide or move to the desired clamping position. This is particularly useful for nuts with a hexagonal cross-sectional profile.

[0059] In the embodiment shown in Figures 6A, 6B and 6C, or in the preferred embodiment shown in Figures 9A and 9B, the clamping device 76 may further comprise a retaining lever 80. The retaining lever holds the blind fastener in the clamping device during clamping by the jaws. The retaining lever 80 is explained in more detail in Figures 6A-6C or 9A and 9B. In Figures 6A or 9A or 9B, the retaining lever closes the joining path and the jaws are open. Thus, the blind fastener can emerge in the receiving assembly in the part of the joining path coaxial with the screw tool, and the blind fastener cannot fall further. Then, the jaws 78 close as shown in Figure 6B, and the retaining lever 80 still closes the joining path 70. The blind fastener held by the jaws is then ready to be engaged with the screw tool 34.

[0060] The elastic element or spring S can be arranged beyond the screw tool, more specifically between the screw tool and the tool shaft (see FIG. 2 or FIG. 3). The tool shaft 32 can have a recess provided at the free end of the rear segment, the spring being partially accommodated in the recess. The elastic element S. ensures axial compensation when the blind fastener is in the clamping device for engagement with the screw tool. In practice, depending on the blind fastener, its internal thread or its position in the clamping device, compensation along the longitudinal axis may be necessary. Thus, a spring-loaded mandrel is formed.

[0061] Finally, once engagement with the screw tool has been made, the retaining levers clear the mating path and the jaws open. At this point, the blind fastener engaged with the screw tool is ready for the installation step into the workpiece.

[0062] Nose In a preferred embodiment, a sensor is provided at the front end of the device, which can be, for example, a radar sensor or an image sensor, so that the exact location of the hole is known and no tolerance compensation is required or, if required, compensation of the hole location estimate is possible.

[0063] In a particular embodiment, as shown in Figures 10A and 10B, a nose portion 82 is provided at the end of the tool housing portion 26. The blind fastener 20 is configured to emerge through the nose portion 82 and be guided by the nose portion 82 into a hole in a workpiece. The nose portion 82 comprises a cylindrical housing 84 within which the blind fastener can be driven by a drive shaft and a screw tool 34. The screw tool 34 can extend into the cylindrical housing 84 and slide within the cylindrical housing 84. The nose portion 82 can comprise a self-centering device 86, which is slidably mounted to the tool housing portion. Such a self-centering device makes it possible to compensate for tolerances when introducing the blind fastener 20 into the hole in the workpiece. In practice, manufacturing tolerances always appear, even if the location of the hole is known before the installation step so that the installation tool knows where to introduce the blind fastener. For example, the self-centering device 86 can comprise two centering rods and three springs 88 arranged in three different directions in the cylindrical housing 84, so that the nose 82 can move and center after the crimping step. The springs allow the elastic return of the nose 82 in the rest position. The screw tool 34 can be connected to the tool shaft via a ball joint connection 90, as can be seen in Figs. 10A and 10B. For example, a centering shaft 92 with two ball joint connections 90, 94 at each end is arranged between the screw tool 34 and the tool shaft 32. A first ball joint connection is provided between the centering shaft and the screw tool 34, while a second ball joint connection is provided between the centering shaft 92 and the screw tool 32. This allows for an accurate centering of the blind fastener with respect to the hole. In Fig. 10A, the nose is centered. In Fig. 10B, the nose is eccentric. Thus, when the blind fastener 20 is inserted into a hole in a workpiece, tolerance compensation can be achieved while seeking out the hole.

[0064] In a preferred embodiment, the radar sensor can locate the holes and no tolerance compensation is required.

[0065] method The blind fastener 20 can be installed in a hole in a workpiece using the installation tool described above as follows.

[0066] In a first step, the blind fastener is fed through a feeder with a delivery tube. The blind fastener 20 is fed, for example, with compressed air. The blind fastener then reaches the receiving assembly 68 and is held in the clamping device 76 by the holding lever. The jaws grab the blind fastener.

[0067] Both motors rotate together at different predetermined speeds to move the screw tool so that it engages the internal threads of the blind fastener 20 .

[0068] The blind fastener engaged with the screw tool 34 is then driven through the tool housing part and out of the cap C which forms the front end of the device housing part. More specifically, the cap C is placed at the free end of the tool nose part 14. A sleeve anvil 140 is provided on the screw tool and the screw tool 34 with the blind element is translated until the jaws close in the recess G which is placed in front of the anvil sleeve on the screw tool 34. The screw tool 34 is then moved backwards so that the anvil sleeve 140 contacts the closed jaws 78. At this point, the nut is ready to be installed in the hole.

[0069] The entire assembly is then driven so that the blind fasteners are inserted into holes in a workpiece by a robot arm, for example, which can move the entire installation tool 10.

[0070] Once the head of the blind element is placed on the surface of the workpiece and the shank is placed in the hole, the second motor 38 is prevented from rotating and the first motor 36 can rotate, causing a linear movement of the solid roller screw and the screw tool in a second direction opposite to the direction of the hole. A part of the screw tool 34 moves backwards in the installation tool, thus crushing a part of the blind fastener (the head of the blind fastener, which is supported by the anvil sleeve, does not move during the crimping step). For example, the load can be up to 30 or 35 kilonewtons. The tool shaft and the screw tool move during the crimping step to allow the formation of a bulge in the shank of the blind fastener, while the tool housing part remains in the same place. The screw tool, the tool shaft and the solid roller screw slide in the tool housing part. Finally, a torque test can be performed to check the crimping function.

[0071] Once the crimping step is performed and the jaws open, the anvil sleeve is retracted by an internal compression spring and both motors rotate together at different specific speeds to move the screw tool 34 to separate the crushed blind fastener. An on-off torque test can be performed to check the threads.

[0072] Torque monitoring can be realised by means of a second motor. If the torque is too high compared to a reference point or a reference curve, an alarm can be generated during the setting process, for example when screwing into or unscrewing from the blind element, highlighting the malfunction. Thus the torque can be monitored throughout the entire installation process.

[0073] The roller screw and screw tool retract until the feed path is free for the next feed.

[0074] 14A and 14B show the speed, torque and angle curves of the first motor, which are particularly correlated to the values ​​of the roller screw, because the second motor holds its position, and therefore the speed of the roller screw corresponds approximately to the speed of the first motor, and the position of the roller screw corresponds approximately to the position of the first motor. Both the first and second motors 36, 38 have a motor resolver that indicates the local position of the motor at every moment, without considering whether the motor is moving or not. Therefore, based on the calculation of the gears, the linear and angular position of the roller screw 40 can be known at every moment. Both motors are also equipped with torque transducers to measure and record the torque. The torque increase observed on the roller screw 40 may correspond to the accelerations and reaction forces caused by the mechanical components, the gears, their mass, the fastening process, etc.

[0075] FIG. 14A shows the speed, torque and angle of the first motor. C1 represents the speed, C2 the torque and C3 the angle of the first motor. The curves represent the situation when the first motor 36 is working and the second motor 38 holds its position. P1, P2 and P3 are torque peaks that usually need to be avoided to reduce wear. More specifically, the first peak P1 is due to the acceleration and the starting moving mass. The second and third peaks P2 and P3 are due to the sudden stop of the first motor 36 when the installation process needs to stop moving or when a new step of the installation process that requires the motor to stop is involved. To limit the peaks P2 and P3, the goal is to make the entire speed curve C1 symmetrical until the deceleration goes down to zero and there are no sudden stops.

[0076] 14B shows the speed, torque and angle of the first motor when the position of the second motor is held dynamically. The torque force resulting from stopping the first motor 36 is released through the second motor 38 so that no torque peak occurs and the roller screw stops exactly as desired. In fact, the roller screw 40 is stopped by its mechanical counterpart which is generating the torque peaks and frictional forces of the system. This allows for a long life of the gears by minimizing the torque peaks.

[0077] A similar strategy can also be used if unexpected torque is observed during normal use of the tool: if the system observes an abnormally high torque, the controller can shut down the first motor and release the second motor, avoiding torque peaks that may occur if only the first motor 36 is shut down.

[0078] The tool nose 14 is provided with an anvil sleeve as a stop for the crimping operation. The roller screw moves the load pin assembly in the position where the clamp jaws are closed. When the load pin moves backwards, the anvil sleeve contacts the clamp jaws with a certain force (detected by a load cell and / or torque transducer). At this point the nut is ready and the tool can move forward with the nut into the hole / opening in the seat. When the shoulder of the nut seats on the upper surface of the seat (detected by a displacement transducer), the crimping process begins. For this, the roller screw, and therefore the load pin assembly, retracts with a certain force and distance inside the tool. This causes the screw tool 34 to move against the anvil sleeve, which cannot be moved by the clamp jaws. The mandrel crimps the nut to form a bulge on the back side of the hole / opening. After the crimping process the clamp jaws open and the anvil sleeve retracts due to an internal compression spring. The roller screw, and therefore the load pin assembly, retracts until the screw tool 34 is disengaged and the feed path is free for the next feed. [Explanation of symbols]

[0079] 10 Installation tools 18 Feeder 26 Tool housing part 28 First housing part 30 Second housing part 32 Tool shaft 34 Screw tools 36 First Electric Motor 38 Second Electric Motor 66 Fastener delivery tube 68 Receiving Assembly 70 Conjugation pathway.

Claims

1. An installation tool (10) for a blind fastener, comprising: a first electric motor (36) having a first drive shaft disposed within the first housing portion (28) and coupled to the tool housing portion (26) via a first transmission; a tool shaft (32) disposed within the tool housing portion (26), the tool shaft (32) having a screw tool (34) coupled thereto, the screw tool (34) adapted for rotational and translational movement along and about a longitudinal axis (X) between a retracted position and an extended position; a feeder (18) having a fastener delivery tube (66) coupled at a first end to a blind fastener source and coupled at a second end to the tool housing portion (26) for delivering the blind fasteners into the tool housing portion (26) in front of the screw tool (34) when the screw tool is in the retracted position; a second electric motor (38) having a second drive shaft disposed within the second housing portion (30) and coupled to the tool housing portion (26) via a second transmission; Equipped with The installation tool (10), wherein the delivery tube (66) is coupled to the tool housing portion via a receiving assembly (68) that includes a mating passage (70) that directly connects the delivery tube to the tool housing portion, and the screw tool (34) is adapted to engage with a blind fastener in the tool housing portion.

2. 2. The installation tool (10) of claim 1, wherein the tool housing portion (26) comprises a solid roller screw (40) coupled to the tool shaft, a shaft gear (48) having an anti-rotation sleeve (48) disposed around the solid roller screw (40), and the shaft gear is coupled to the second electric motor via a second housing gear (62).

3. 3. The installation tool (10) of claim 2, wherein the solid roller screw (40) coupled to the tool shaft (32) has a first end coupled to the tool shaft and a second end opposite the first end, and an anti-rotation hub (46) of the solid roller screw is disposed at the second end.

4. 4. The installation tool (10) of claim 2 or 3, wherein the second housing part (30) comprises the second electric motor having the second drive shaft and a second housing gear, and the first housing part (28) comprises the first electric motor (36) and a first housing gear (58), the first housing gear (58) being coupled to a tool gear (52), the tool gear (52) being fixedly coupled to a roller screw nut (50) disposed within the tool housing part and disposed around the solid roller screw (40).

5. The installation tool (10) of any of claims 2 to 4, wherein rotation of the first drive shaft results in linear motion of the solid roller screw (40).

6. 6. An installation tool (10) as claimed in any one of claims 1 to 5, wherein rotation of the first and second drive shafts at different rotational speeds results in linear and rotational movement of the screw tool (34) such that the screw tool can engage a blind fastener.

7. 7. An installation tool (10) as claimed in any one of claims 1 to 6, wherein the delivery tube (66) extends parallel or substantially parallel to the tool housing part (26), the joint path (70) comprises a first portion coaxial with the delivery tube and a portion aligned with the longitudinal axis (X), and the joint path (70) is configured to deliver the blind fastener into the tool housing part.

8. 8. The installation tool (10) of any of claims 1 to 7, further comprising a clamping device (76) configured to clamp a blind fastener for engagement with the screw tool, the clamping device (76) being disposed within the tool housing portion.

9. 9. The installation tool (10) of claim 8, wherein the clamping device (76) comprises two movable jaws configured to clamp the blind fastener, the movable jaws (78) being positively actuated.

10. 10. The installation tool (10) of claim 9, wherein the clamping device (76) further comprises a retaining lever (80) such that the blind fastener is retained within the clamping device during clamping by the jaws (78).

11. 11. An installation tool (10) according to claim 9 or 10, wherein each of the jaws comprises a capture surface having a first and a second segment, the first segment being aligned relative to the second segment, the first segment being flat and the second segment comprising a bulge configured to provide an asymmetric shape to orient the blind element in the clamping device.

12. The installation tool (10) of any of claims 9 to 11, wherein the screw tool comprises an anvil sleeve (140) configured to contact the movable jaw (78).

13. 11. The installation tool (10) of claim 1, wherein the tool shaft comprises a front segment (100) and a rear segment (102), an intermediate segment (104) is disposed between the front and rear segments (100, 102), and the front segment (100) comprises a first portion (106) coupled to a flange (108) via a groove (110).

14. 12. The installation tool (10) of claim 11, wherein the flange comprises a plurality of evenly distributed holes (112) configured to receive jackbolts, and the groove has multiple radii of curvature.

15. 15. A method of installing blind fasteners using an installation tool according to any one of claims 1 to 14, wherein the torque of a roller screw is monitored and undesirable torque peaks are avoided by stopping the first motor (36) and disengaging the second motor (38).

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