Sensor arrangement, component handling arrangement and method for feeding a component

Abstract

According to the present invention, a sensor arrangement is provided comprising: an inductive sensor that can be arranged at a fixed position within the sensor arrangement; a support arrangement comprising an anchor element that can be arranged at a fixed position within the support arrangement; a movable element that is movable relative to the anchor element, wherein the movable element comprises a foot section that is suitable for interacting with a receiving head arrangement, a metallic head section that interacts with a magnetic field generated by the inductive sensor; and a spring element that is arranged such that the spring between the anchor element and the foot section is compressed when the foot section is moved in the direction of the anchor element;and wherein the inductive sensor is operable to provide an output signal, the value of which depends on the distance between a reference point and the metallic head element such that the output signal represents a measure of the amount by which the spring element between the anchor element and the foot section has been compressed. A component handling arrangement comprising the sensor arrangement is further provided; as is a method for feeding a component to a receiving surface using the component handling arrangement.

Description

Field of the invention

[0001] The present invention relates to a sensor assembly comprising an inductive sensor and a support assembly, wherein the inductive sensor is operable to provide an output signal to a controller, the output signal indicating the amount by which a spring element in the support assembly is compressed. Furthermore, a component handling assembly employing the sensor assembly is provided; and a method for feeding a component to a receiving surface employing the component handling assembly. Background of the invention

[0002] Many component handling assemblies include a feed station where a component held on a pick-up head of a pick-up element is fed to a pick-up surface (e.g., the components are fed onto the surface of a shuttle designed to transport the components to another station). The pick-up element is typically located on the edge of a rotating turret and extends away from the turret to move the pick-up head into a position above the pick-up surface.The position of the pick-up head holding the component relative to the pick-up surface is crucial to ensure satisfactory delivery of the component to the pick-up surface: If the pick-up head is too far from the pick-up surface, the component must fall a greater distance and be displaced from a predefined target position when it hits the pick-up surface; in other words, if the pick-up head is too far from the pick-up surface, it will not be possible to precisely place the component at a predefined target position on the pick-up surface. On the other hand, if the pick-up head is brought too close to the pick-up surface, the component will be compressed between the pick-up head and the pick-up surface and damaged.

[0003] In component handling assemblies, a drive element of an actuator pushes on the pick-up element to extend it away from the turret in such a way that the pick-up head is moved into a position in which it transfers the component it holds to the pick-up surface; accordingly, the position of the pick-up head is directly related to the position of the drive element.

[0004] Existing solutions to ensure optimal distance between the pick-up head and the workpiece first involve determining a target position for the drive element in a calibration step: During calibration, the pick-up surface (e.g. the shuttle) is positioned under the pick-up head in a predefined target position and then the drive element is moved to push the pick-up and bring the pick-up head to a predefined height above the pick-up surface; once the pick-up head is at the predefined height above the pick-up surface, the position of the drive element is determined using a sensor / tracking sensor (e.g. an optical encoder) and the measured position defines the target position. In all subsequent operations where a component is transferred to a pick-up surface, the pick-up surface (e.g.the shuttle) at a position corresponding to the predefined target position, and the drive element is moved to a position corresponding to the target position (the position is determined using a sensor (e.g. an optical encoder)), and the component is then transferred to the pick-up surface.

[0005] Existing solutions for ensuring an optimal distance between the pick-up head holding the component and the pick-up surface are inadequate, at least because they cannot take into account changes or variations that occur within the component handling arrangement (e.g., changes or variations that occur within the component handling arrangement during operation and / or after operation).For example, parts of the component handling assembly are subject to thermal expansion during use, and changes in the dimensions of these parts, in turn, lead to variations in the distance between the pick-up head that holds the component and the pick-up surface. Parts of the component handling assembly are subject to wear over time, leading to changes in the relative positioning of the parts within the component handling assembly and / or allowing greater play in the positions of the parts within the component handling assembly, which in turn leads to variations in the distance between the pick-up head that holds the component and the pick-up surface. Furthermore, variations in the pick-up surface also lead to variations in the distance between the pick-up head that holds the component and the pick-up surface.For example, the pick-up surface is typically a surface of a shuttle, and the shuttle's alignment may be tilted such that some parts of the pick-up surface are closer to the pick-up head than others. To achieve a precise distance between the pick-up head holding the component and the shuttle's pick-up surface, the shuttle's alignment must be precise. In practice, achieving consistent, precise alignment (e.g., consistent, precise planarity) of the shuttle for multiple iterations over time is difficult and costly.

[0006] The aim of the present invention is to mitigate or eliminate at least some of the above-mentioned problems / disadvantages associated with existing solutions. Summary of the invention

[0007] According to the present invention, this object is achieved by a sensor arrangement having the features recited in independent claim 1 and / or by a component handling arrangement having the features recited in independent claim 6 and / or by a method having the steps recited in independent claim 13. The dependent claims recite advantageous, optional features of various embodiments of the inventions. Short description of the drawings

[0008] Embodiments of the invention, given only by way of example, are described in the detailed description with reference to the following drawings, in which: Fig. 1a is a perspective view of a sensor assembly according to an embodiment of the present invention; Fig. 1b a side view of the sensor arrangement of Fig. 1a is; Fig. 1c a cross-sectional view of the sensor arrangement of the Fig. 1a and Fig. 1b is; Fig. 2 is a perspective view of a component handling assembly according to an embodiment of the present invention; Fig. 3 a side view of the component handling arrangement of the Fig. 2 is. Detailed description of the embodiments of the invention

[0009] Fig. 1a is a perspective view of a sensor assembly 1 according to an embodiment of the present invention; Fig. 1b is a side view of the sensor assembly 1; and Fig. 1c is a cross-sectional view of the sensor assembly 1.

[0010] With reference to the Fig. 1a, Fig. 1b and Fig. 1c shows that the sensor assembly 1 comprises a support assembly 3. The support assembly 3 is selectively movable by a movable drive element 19 of a drive assembly 19b.

[0011] The sensor assembly 1 further comprises an inductive sensor 2 having a sensor surface 12. The inductive sensor 2 is attached to the support assembly 3. It should be noted that in one embodiment, the position of the inductive sensor 2 on the support assembly 3 may be adjustable; for example, the inductive sensor 2 may be mounted on the support assembly 3 by a mounting module having a position adjustment device that allows the inductive sensor 2 to be moved to a higher fixed position or to a lower fixed position within the sensor assembly 1. However, adjusting the fixed position of the inductive sensor 2 is not an essential feature of the present invention.

[0012] The support assembly 3 comprises a head element 8 having a channel 8a formed therein. In this example, the head element 8 further comprises a guide element 8b located in the channel 8a; the guide element 8b is not essential to the invention.

[0013] The support assembly 3 further comprises an anchor element 4, which can be arranged at a fixed position within the support assembly 3. In a preferred embodiment, the position of the anchor element 4 in the support assembly 3 can be adjustable.

[0014] In this embodiment, the anchor element 4 comprises a plate 4a arranged at a fixed position within the support assembly 3. The plate 4a has a through-opening 4b formed therein. The plate 4a is preferably attached to the support assembly 3 (preferably to a fixed part of the support assembly 3) via one or more screw elements; the fixed position of the plate 4a is selectively adjustable by screwing in or unscrewing the one or more screw elements. As shown in Fig. As shown in Figure 1c, the plate 4a is attached to a fixed part 106 of the support assembly 3 via a screw element 104; the fixed position of the plate 4a is selectively adjustable by screwing in or unscrewing the screw element 104, such that the plate 4a can be moved to a higher or lower position, respectively.

[0015] The sensor assembly 1 further comprises a movable element 6. The movable element 6 comprises a base portion 211, a metallic head portion 11, and a shaft element 15 connected between the base portion 211 and the metallic head 11. The shaft element 15 is fixedly connected at one end 15a to the metallic head portion 11 and at its other end 15b to the base portion 211.

[0016] The shaft element 15 is arranged such that it extends through the through opening 4b defined in the anchor element 4, so that the metallic head portion 11 is arranged on one side of the anchor element 4 and the foot portion 211 is arranged on the other, opposite side of the anchor element 4.

[0017] The metallic head portion 11 is located between the armature element 4 and the inductive sensor 2. The metallic head portion 11 can interact with a magnetic field generated by the inductive sensor 2. In this embodiment, the inductive sensor 2 and the movable element 6 are arranged such that the sensor support 12 is aligned with the metallic head portion 11.

[0018] The foot portion 211 is located within the channel 8a of the head member 8; more specifically, the foot portion 211 is located within the guide member 8b, which is located in the channel 8a of the head member 4. A free end 211a of the foot member 211 protrudes from the guide member 8b. The foot portion 211 further includes a tip member 16 adapted to abut a pickup head assembly. The tip member 16 protrudes from the free end of the foot portion 211. In this embodiment, the tip member 16 is partially embedded in the foot portion 211; however, it should be understood that the tip member 16 could alternatively be mounted on a surface of the free end of the foot portion 211. In this embodiment, the tip member 16 is made of a rubber material; however, it should be understood that the tip member 16 may have any suitable composition.

[0019] The movable element 6 is movable with respect to the support assembly 3 and the inductive sensor 2: the foot portion 211 can move linearly through the guide element 8b (and / or the foot portion 211 can move linearly through the channel 8a) and the shaft element 15 can move linearly through the through-opening 4b of the anchor element 4.

[0020] The sensor assembly 1 further comprises a spring 9 arranged between the anchor element 4 and the base element 211. In the embodiment, a first end 9a of the spring 9 abuts or is attached to the base element 211, and a second, opposite end 9b of the spring 9 abuts or is attached to the anchor element 4. As shown in Fig. As can be seen in Figure 1c, the first end 9a of the spring 9 bears against or is attached to a second end 211b of the foot element 211, which is opposite the free end 211a; this second end 211b of the foot element 211 is attached to the shaft 15; the second, opposite end 9b of the spring 9 bears against or is attached to the surface of the anchor element 4 which faces the foot element 211.

[0021] It is possible to selectively adjust the fixed position of the anchor element 4 by screwing or unscrewing the screw element 104 in order to move the anchor element 4 to a higher or lower position and thus to take into account different spring lengths / forces.

[0022] The inductive sensor 2 is operable to provide an output signal, the value of which depends on the distance between the metallic head portion 11 and the sensor pad 12 of the inductive sensor 2, such that the value of the output signal is representative of the amount by which the spring element 9 is compressed between the armature element 4 and the base portion 211. The amount by which the spring element is compressed is thus representative of the force exerted on the tip element 16. In this embodiment, the value of the output signal increases the more the spring element 9 is compressed; in other words, when the spring element 9 is fully compressed, the value of the output signal of the inductive sensor 2 reaches a maximum value; and when the spring element 9 is fully uncompressed, the value of the output signal of the inductive sensor 2 reaches a minimum value.

[0023] When a force greater than the biasing force exerted by the spring 9 on the base element 211 is applied to the tip element 16, the movable element 6 is moved such that the base portion 211 is moved toward the anchor element 4 (the base element 211 moves through the guide element 8b (and / or the channel 8a) toward the anchor element 4). In one embodiment, the free end 211a of the base element 211 can be moved into the guide element 8b (and / or the channel 8a), with only a portion of the tip element 16 forming a projection from the guide element 8b (and / or the channel 8a); the shaft element 15 moves through the through-opening 4b when the base portion 211 moves toward the anchor element 4; and the spring element 9 is compressed between the anchor element 4 and the base portion.Since the shaft 15 is firmly connected at one end 15a to the metallic head portion 11 and at its other end 15b to the base portion 211, the metallic head portion 11 moves accordingly. When the base portion 211 moves in the direction of the anchor element 4, the metallic head portion 11 also moves accordingly in the direction of the sensor surface 12 of the inductive sensor 2, whereby the distance between the sensor surface 12 and the metallic head portion 11 is reduced and the output value of the inductive sensor 2 increases.

[0024] Likewise, when the movable element 6 moves such that the foot portion 211 is moved in a direction away from the anchor element 4 (e.g., the movable element 6 can be moved such that the foot portion 211 is moved in a direction away from the anchor element 4 (the foot portion 211 moves through the guide element 8b (and / or the channel 8a) in a direction away from the anchor element 4), by a force exerted by the spring element 9 on the foot portion 211 when the spring element 9 is in a compressed state (i.e.when the spring element 9 is compressed between the foot portion 211 and the anchor element 4, 9 returns to a non-compressed state, thereby exerting a force on the foot portion 211 that moves the foot portion 4 in a direction away from the anchor element 4); since the shaft 15 is fixedly connected to the metallic head portion 11 at one end 15a thereof and fixedly connected to the foot portion 211 at the other end 15b thereof, the metallic head portion 11 also moves accordingly in a direction away from the sensor mat 12, thereby increasing the distance between a sensor mat 12 and the metallic head portion 11 and decreasing the value of the output signal of the inductive sensor 2.

[0025] The sensor assembly 1 further comprises a mounting module 18 configured such that the sensor assembly 1 is attachable to a drive assembly 19b comprising a movable drive element 19. The carrier assembly 3 is movable relative to the mounting module 18. The drive element 19 of the drive assembly 19b can cooperate with the carrier assembly 3 to selectively move the carrier assembly 3. The mounting module 18 can be attached to the drive assembly 19b such that the mounting module and the drive assembly have a fixed position; the drive element 19 is selectively actuated to move and exert a force on the carrier assembly 3 to urge the carrier assembly 3 to move in a direction toward a pickup element.

[0026] Fig. 2 is a perspective view of a component handling assembly 20 according to an embodiment of the present invention; Fig. 3 is a side view of the handling assembly 20. Referring to the Fig. 2 and Fig. 3, it can be seen that the component handling assembly 20 comprises a turret arm element 21 with a pickup element 22. The pickup element 22 comprises a pickup head 23. The pickup element 22 is movable relative to the turret arm element 21 between a first position in which the pickup head 23 of the pickup element 22 has a minimum distance from the turret arm element 21 and a second position in which the pickup head 23 of the pickup element 22 has a maximum distance from the turret arm element 21.

[0027] The component handling assembly 20 further includes a biasing means 24 that biases the pickup element 22 toward its first position. In this embodiment, the biasing means 24 comprises a blade 24 that is attached at a first end 24a thereof to the turret arm element 21 and at a second, opposite end 24b thereof to an upper portion 22a of the pickup element 22. When the pickup element 22 is moved to its first position, the second end 24b of the blade 24 moves along with the pickup element 22, while the first end 24a of the blade remains in a fixed position; thus, when the pickup element 22 is moved toward its first position, the blade 24 is bent; When the blade 24 is in its bent state, it exerts a tensile force on the upper portion 22a of the pickup element 22, thereby biasing the pickup element 22 toward its first position.It is understood that in the present invention, the biasing means 24 may take any suitable form and is not limited to a blade 24.

[0028] The component handling assembly further comprises an airflow generating means 25 that is selectively operable to generate a negative airflow or a positive airflow. The airflow generating means 25 is fluidly connected to the pickup element 22 such that a vacuum can be selectively provided to the pickup head 23 such that a component can be held by the vacuum on the pickup head 23 when the airflow generating means is actuated to generate a negative airflow; and such that a component held on the pickup head can be blown by the pickup head 23 onto a receiving surface when the airflow generating means 25 is actuated to generate a positive airflow. In this embodiment, the airflow generating means 25 is fluidly connected to the pickup element 22 via a conduit 25a.

[0029] The component handling arrangement 20 further comprises a drive assembly 19b and a sensor arrangement 1 according to one of the previously mentioned embodiments of the sensor arrangement 1.

[0030] The drive assembly 19b comprises at least one motor and one drive element 19 (in the Fig. 2 or Fig. 3 not visible, but in the Fig. 1b, Fig. 1c), which is connected to the motor such that the motor can move the drive element 19 in a first direction (indicated by arrow 31a) or in a second, opposite direction (indicated by arrow 31b). The first direction 31a is a direction directed toward the pickup element 22, while the second direction 31b is a direction directed away from the pickup element 22.

[0031] The sensor arrangement 1 is attached to the drive assembly 19b via the mounting module 18. The carrier arrangement 3 of the sensor arrangement 1 is movable with respect to the mounting module 18. The drive element 19 of the drive assembly 19b can cooperate with the carrier arrangement 3 to selectively move the carrier arrangement 3 towards a pickup element 22. The sensor arrangement 1 is arranged such that the drive element 19 (in the Fig. 2 or Fig. 3 not visible, but in the Fig. 1b, Fig. 1c) of the drive assembly 19b is selectively operable to exert a force on the support assembly 3 of the sensor assembly 1 to move the support assembly 3 in the first direction 31a toward the pickup element 22. (The inductive sensor 2, the armature element 4, and the movable element 6 all move together with the support element 3 toward the pickup element 22).

[0032] The sensor assembly 1 is arranged such that the foot portion 211 (more precisely, the tip element 16 of the foot portion 211) is aligned over or abuts against the upper portion 24a of the pickup element 22, such that when the motor of the drive assembly 19b is actuated to move the drive element 19 in the first direction 31a, the drive element 19 of the drive assembly 19b exerts a force on the support assembly 3 of the sensor assembly 1 to move the support assembly 3 in the first direction 31a towards the pickup element 22, such that the tip element 16 of the foot portion 211 of the sensor assembly 1 exerts a force on the pickup element 22 (wherein the exerted force is greater than and counteracts the biasing force exerted on the pickup element 22 by the biasing means 24) to move the pickup element 22 from its first position to its second position.

[0033] The spring element 9 in the sensor assembly 1 has a spring stiffness high enough to withstand a force corresponding to the preload force exerted by the biasing means 24 on the pickup element 22 when the pickup element 22 is in its second position, so that compression of the spring element 9 only occurs in response to a counterforce exerted on the pickup head 22. More specifically, in this embodiment, the spring element 9 has a spring stiffness high enough to withstand a force corresponding to the tensile force exerted by the blade 24 on the upper portion 22a of the pickup element 22 when the pickup element 22 is in its second position.

[0034] The component handling assembly 20 further comprises a controller 40 that is operatively connected to the inductive sensor 2 of the sensor assembly 1 such that the controller 40 can receive the output signal of the inductive sensor 2, and that is also operatively connected to the drive assembly 19b such that the controller 40 can control the motor of the drive assembly 19b. The controller 40 is configured to operate the motor of the drive assembly 19b such that the drive element 19 is moved in a first direction 31a until the output signal of the inductive sensor 2 increases and lies within a predefined range. In a preferred embodiment, the predefined range lies between a value non-zero and a predefined maximum value, wherein the predefined maximum value is equal to an output signal of the inductive sensor 2 when the spring element 9 is compressed by 50 µm.In another embodiment, the predefined range lies between a predefined minimum value and a predetermined maximum value, wherein the predefined minimum is equal to an output of the inductive sensor 2 when the spring element 9 is compressed by 10 µm, and the predetermined maximum value is equal to the output of the inductive sensor 2 when the spring element 9 is compressed by 50 µm.

[0035] The controller 40 is also operably connectable to the airflow generating device 25; the controller is configured to selectively operate the airflow generating device 25 to generate a negative airflow and / or a positive airflow.

[0036] The component handling assembly 20 can be used according to one of the aforementioned embodiments of the component handling assembly to perform a method for feeding a component held on a pick-up head to a pick-up surface, according to a further aspect of the present invention, the method comprising the steps of moving a pick-up head holding a component toward a pick-up surface such that the component is pressed against the pick-up surface, and the pick-up surface exerts a reaction force on the component that forces the foot portion 211 of the movable element 6 to move toward the anchor element 4, thereby compressing the spring element 9 between the anchor element 4 and the foot portion 211; the pick-up head holding a component is further moved toward the pick-up surface until the output of the inductive sensor 2 increases and lies within a predefined range.As a result, the component held on the pick-up head 23 can be placed on the pick-up surface with the desired force, even if fluctuations in the distance between the respective pick-up heads 23 and the pick-up surfaces (e.g., the surfaces of the respective shuttles that pick up components from the respective pick-up heads 23) occur during operation of the component handling arrangement 20.

[0037] In a preferred embodiment of the method, if, after the drive element 19 has moved in the first direction 31a by a distance equal to the predefined threshold distance, the output signal of the inductive sensor 2 is not within a predefined range (i.e. the output signal of the inductive sensor 2 has not increased sufficiently to be within the predefined range), the method further comprises the following steps: iteratively moving the drive element 19 (e.g.Operating the motor of the drive assembly 19b to move the drive element 19 in predefined increments in the first direction 31a such that the tip element 16 of the foot portion 211 is moved in corresponding predefined steps in the first direction 31a towards the pickup element 22 to cause the pickup head 23 to move in corresponding predefined steps towards the pickup surface until the output signal of the inductive sensor 2 increases and is within the predefined range.Thus, the preferred embodiment may include the steps of detecting that the drive element has moved a distance equal to the predefined threshold distance and that the output signal of the inductive sensor is not within a predefined range; in response to this detection, iteratively moving the drive element in predefined increments such that the pickup head 23 is moved toward the pickup surface in corresponding predefined increments until the output signal of the inductive sensor increases and is within the predefined range. In one embodiment, the predefined increments are in the range of 0.001 mm to 0.05 mm.

[0038] During operation of the component handling assembly 20: The pick-up element 22 is initially in its first position; the spring element 9 is thus initially in a non-compressed state. The controller 40 has controlled the airflow generating device 25 such that the airflow generating device 25 generates a negative airflow to create a vacuum on the pick-up head 23; this vacuum holds a component to be delivered to a pick-up surface on the pick-up head 23. In this example, the pick-up surface is a surface of a movable shuttle; however, it should be understood that the present invention is not limited to the pick-up surface being defined by a surface of a shuttle. The component in question may have been picked up by the pick-up element 22 from a processing station or test station.

[0039] A shuttle having a surface capable of receiving one or more components is positioned beneath the receiving head 23. The shuttle may be arranged on a rail and move to a position where its surface is aligned beneath the receiving head 23.

[0040] While the component is held by vacuum on the pickup head 23, the controller 40 actuates the motor of the drive assembly 19b to move the drive element 19 in a first direction 31a. The first direction 31a is a direction toward the pickup element 22.

[0041] The drive element 19 of the drive assembly 19b exerts a force on the support assembly 3 of the sensor assembly 1 to move the support assembly 3 in the first direction 31a toward the pickup element 22 and to bring the tip element 16 of the base portion 211 into contact with the pickup element 22. While the drive element 19 of the drive assembly 19b continues to exert a force on the support assembly 3 of the sensor assembly 1 to move the support assembly 3 in the first direction 31a toward the pickup element 22, the force from the drive element on the support assembly 3 is transmitted to the tip element 16 of the base portion 211 such that the tip element 16 of the base portion 211 exerts a force on the pickup element 22 to move the pickup element from its first position toward its second position.

[0042] Since the spring element 9 in the sensor assembly 1 has a spring stiffness that is high enough to withstand a force corresponding to the preload force exerted by the biasing means 24 on the pickup element 22 when the pickup element 22 is in its second position, the movement of the pickup element 22 from its first position towards its second position does not cause any compression of the spring element 9 in the sensor assembly 1. More specifically, since the spring element 9 has a spring stiffness that is high enough to withstand a force corresponding to the tensile force exerted by the blade 24 on the upper portion 22a of the pickup element 22 when the pickup element 22 is in its second position, the movement of the pickup element 22 from its first position to its second position does not cause any compression of the spring element 9 in the sensor assembly 1.

[0043] However, once the component held by the pickup head 23 rests against the surface of the shuttle, the surface of the shuttle blocks the pickup head 23 from further moving in the first direction 31a; this results in a reaction force exerted by the surface of the shuttle on the component, which is pressed by the pickup head 23 onto the shuttle surface. This reaction force is transmitted through the component, through the pickup head 23, and through the pickup element 22 to the tip element 16 of the foot portion 211 of the movable element 6.

[0044] The reaction force forces the foot portion 211 of the movable element 6 to move toward the anchor element 4, causing compression of the spring element 9 between the anchor element 4 and the foot portion 211. The more the drive element 19 moves in a first direction 31a, the greater the reaction force transmitted to the tip element 16 of the foot portion 211 of the movable element 6, and the more the spring element 9 is compressed between the anchor element 4 and the foot portion 211.

[0045] The controller 40, which is operatively connectable to the inductive sensor 2 of the sensor assembly 1, receives the output signal of the inductive sensor 2. The controller 40 operates the motor of the drive assembly 19b to move the drive element 19 further in the first direction 31a until the output signal of the inductive sensor 2 increases and lies within a predefined range. In this embodiment, the predefined range lies between a predefined maximum value and a predefined minimum value, wherein the predefined maximum value is equal to the output of the inductive sensor 2 when the spring element 9 is compressed by 50 µm, and the predefined minimum value is equal to the output of the inductive sensor 2 when the spring element 9 is compressed by 10 µm.(The less the spring element 9 is compressed, the greater the distance between the metallic head part 11 and the sensor pad 12 and therefore the smaller the value of the output of the inductive sensor 2; the more the spring element 9 is compressed, the smaller the distance between the metallic head part 11 and the sensor pad 12 and therefore the value of the output signal of the inductive sensor 2 is higher; therefore, the predefined maximum value occurs when the spring element is compressed by 50 µm, and the predetermined minimum value occurs when the spring element 9 is compressed by 10 µm).

[0046] It is understood that the predetermined maximum value and the predetermined minimum value are determined in a calibration step, which is preferably performed prior to use of the component handling assembly 20. The calibration step preferably comprises compressing the spring element by 10 µm and reading and recording the value output by the inductive sensor 2 to obtain the predetermined minimum value; and compressing the spring element by 50 µm and reading and recording the output of the inductive sensor 2 to obtain the predetermined maximum value. In this way, the component handling assembly 20 can always be operated such that the pick-up head 23 exerts a desired force on the component when the component is released onto the pick-up surface, even if the distance between the pick-up head 23 and the pick-up surface fluctuates over time.

[0047] Once the output signal of the inductive sensor 2 increases to a level within a predefined range, the controller 40 prevents the motor of the drive assembly 19b from further moving the drive element 19 in the first direction 31a. At this point, the component is released from the pick-up head 23. To this end, the controller 40 controls the airflow generating means so that the airflow generating means do not generate a negative airflow to eliminate the vacuum used to hold the component on the pick-up head 23. Once the vacuum is eliminated, the component is released from the pick-up head 23 and conveyed to the surface of the shuttle.

[0048] In the preferred embodiment, once the output signal of the inductive sensor 2 increases and is within a predefined range, the controller 40 actuates the airflow generating means to generate a positive airflow; this positive airflow blows the component away from the pick-up head 23, thus assisting in removing the component from the pick-up head 23 (and thus depositing the component on the surface of the shuttle). If the pick-up head 23 exerts a compressive force on the component, this can cause the component to become loosely attached to the pick-up head 23 through friction. The positive airflow overcomes any frictional adhesion between the pick-up head 23 and the component, so that the position of the component on the surface of the shuttle is not shifted when the pick-up head is moved away from the component.However, it should be understood that the application of positive airflow to assist in the removal of the component from the pickup head 23 is not essential to the present invention.

[0049] The controller 40 then actuates the motor of the drive assembly 19b to move the drive element 19 in its second, opposite direction 31b. Accordingly, the force that the drive element 19 exerted on the support assembly 3 of the sensor assembly 1 to move the support assembly 3 in the first direction 31a toward the pickup element 22 is canceled, thereby canceling the force exerted on the pickup element 22 via the tip element 16 of the base portion 211. Since the force exerted on the pickup element 22 via the tip element 16 of the base portion 211 is removed, the biasing force exerted on the pickup element by the biasing means 24 moves the pickup element 22 back to its first position; In particular, the pulling force exerted by the blade 24 on the upper portion 22a of the pickup element 22 moves the pickup element 22 back to its first position.In one embodiment, when moved by the pulling force of the blade 24, the pickup element 22 presses on the tip element 16 of the foot portion 211, causing the carrier 3 to move upward in a direction away from the pickup surface.

[0050] In a preferred embodiment, the component handling assembly 20 of the drive assembly 19b further comprises a distance sensor configured to measure the distance by which the drive element 19 has moved in the first direction 31a from a predefined reference position and output a distance measurement indicative of the measured distance.In this further embodiment, the controller 40 is connectable to the distance sensor such that the controller 40 receives the distance measurement from the distance sensor; the controller 40 is configured to compare the received distance measurement with a predetermined threshold distance, and if the received distance measurement is equal to or greater than the predefined threshold distance, the controller 40 actuates the motor of the drive assembly 19b to move the drive element 19 iteratively in predefined steps in the first direction 31a until the output of the inductive sensor 2 increases and lies within the predefined range. The predefined threshold distance is determined in a calibration step and is the distance by which the drive element 19 has moved in the first direction 31a from a predefined reference position when the pickup head 23 is a predefined distance from a pickup surface (e.g.the surface of a shuttle positioned beneath the pick-up head 23) arranged at a predefined position beneath the pick-up head 23 (the predefined position preferably corresponds to the position that a surface of a shuttle will assume from the pick-up head 23 when the component handling assembly 20 is in use); preferably, the predefined threshold distance is the distance that the drive element 19 has been moved from the predefined reference position in the first direction 31a when the pick-up head 23 occupies a predefined position (or is within a predefined range of positions) in which the component is to be released from the pick-up head 23 onto the pick-up surface.In one embodiment, this means that during operation of the component handling assembly 20, after a shuttle having a pick-up surface has been positioned under the pick-up head 23, if the drive element 19 has moved in the first direction 31a by a distance equal to the predefined threshold distance, but the output of the inductive sensor 2 is not within the predefined range, this means that the pick-up surface (i.e., the surface of the shuttle) is further away from the pick-up head 23 than the distance the pick-up surface was away from the pick-up head 23 during the calibration step (the reason for the pick-up surface being further away from the pick-up head may, for example, be due to thermal expansion of parts of the assembly and / or wear of parts of the assembly).The controller 40 then actuates the motor of the drive assembly 19b to move the drive element 19 iteratively in predefined steps in a first direction 31a until the output of the inductive sensor 2 increases and lies within the predefined range. Therefore, even if a deviation in the distance between the pickup head 23 and the pickup surface has occurred, the component is placed on the pickup surface with the desired force.

[0051] Various modifications and variations of the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope of the invention as defined in the appended claims. Although the invention has been described in connection with specific preferred embodiments, it is to be understood that the claimed invention is not to be unduly limited to such specific embodiments.

Claims

[1] Sensor arrangement, comprising an inductive sensor that can be arranged at a fixed position within the sensor arrangement; a support assembly comprising an anchor element that can be arranged at a fixed position within the support assembly; a movable member movable relative to the armature member, the movable member comprising a foot portion adapted to cooperate with a pickup head assembly and a metallic head portion adapted to interact with a magnetic field generated by the inductive sensor; a spring element arranged such that the spring is compressed between the anchor element and the foot portion when the foot portion is moved toward the anchor element; wherein the inductive sensor is operable to provide an output signal, the value of the output signal depending on the distance between the inductive sensor and the metallic head portion such that the output signal represents the amount by which the spring element is compressed between the anchor element and the foot portion. [2] The sensor assembly of claim 1, wherein the anchor member comprises a plate mountable at a fixed position within the support assembly, and wherein the anchor member has a through-hole formed therein; and wherein the movable member comprises a shaft member connectable between the metallic head portion and the foot portion; and wherein the shaft member is arranged to extend through the through-hole in the anchor member such that the metallic head portion is located on one side of the anchor member and the foot portion is located on the other, opposite side of the anchor member. [3] A sensor assembly according to claim 1 or 2, wherein the base portion includes a tip member adapted to abut a pickup head assembly. [4] Sensor arrangement according to one of claims 1 to 3, wherein the inductive sensor comprises a sensor pad; and wherein the inductive sensor is arranged such that the sensor pad is aligned with the metallic head portion such that the metallic head portion moves towards the sensor pad when the foot portion is moved towards the anchor element and the spring is compressed between the anchor element and the foot portion. [5] Sensor arrangement according to one of claims 1 to 4, wherein the anchoring element is attached to a fixed part of the support arrangement via one or more screws and wherein the fixed position of the anchoring element is selectively adjustable by screwing in or unscrewing the one or more screws. [6] Component handling arrangement, comprising a turret arm member having a pickup member with a pickup head, the pickup member being movable relative to the turret arm member between a first position in which the pickup head of the pickup head member is at a minimum distance from the turret arm member and a second position in which the pickup head of the pickup head member is at a maximum distance from the turret arm member, and biasing means biasing the pickup member toward its first position; a drive assembly comprising at least one motor and a drive member operably mounted on the motor, the motor operable to move the drive member in a first direction or in a second, opposite direction; a sensor arrangement according to any one of claims 1 to 5, wherein the sensor arrangement is arranged such that the foot portion can cooperate with the pickup element such that when the motor of the drive assembly is operated to move the drive element in the first direction, the foot portion exerts a force on the pickup element to move the pickup element from its first position towards its second position. [7] A component handling assembly according to claim 6, wherein the spring element has a spring stiffness high enough to withstand a force corresponding to the biasing force exerted on the pickup element by the biasing means when the pickup element is in its second position, so that compression of the spring element occurs only in response to a counterforce exerted on the pickup head. [8] A component handling assembly according to claim 6 or 7, further comprising a controller operatively connected to the inductive sensor of the sensor assembly such that the controller can receive the output signal of the inductive sensor, and further operatively connected to the drive assembly such that the controller can control the motor of the drive assembly; and wherein the controller is configured to operate the motor to move the drive member in a first direction until the output of the inductive sensor increases and is within a predefined range. [9] A component handling assembly according to claim 8, wherein the predefined range is any non-zero value that is less than a predetermined maximum value, the predetermined maximum value being equal to the output of the inductive sensor when the spring element is compressed by 50 µm. [10] A component handling assembly according to claim 8, wherein the predefined range is between a predefined minimum value and a predetermined maximum value, the predefined minimum being equal to the output of the inductive sensor when the spring element is compressed by 10 µm, and the predetermined maximum value being equal to the output of the inductive sensor when the spring element is compressed by 50 µm. [11] The component handling assembly of any one of claims 6-10, wherein the drive assembly further comprises a distance sensor configured to measure the distance the drive element has moved from a predefined reference position and output a distance measurement indicative of the distance the drive element has moved from the predefined reference position; and wherein the controller is operatively connectable to the distance sensor such that the controller can receive the distance measurement and compare the received distance measurement with a reference distance measurement, and wherein the controller is configured such that, when the distance measurement exceeds a predetermined threshold, it actuates the motor of the drive assembly to iteratively move the drive element in a first direction in predetermined increments until the output of the inductive sensor increases and is within the predetermined range. [12] A component handling assembly according to any one of claims 6-11, wherein the component handling assembly further comprises an airflow generating means selectively operable to generate a negative airflow and / or a positive airflow; wherein the airflow generating means is fluidly connectable to the receiving part such that a vacuum can be selectively provided at the receiving head such that a component can be held at the receiving head by the vacuum when the airflow generating means is operated to generate a negative airflow; and a component held at the receiving head can be blown by the receiving head onto a receiving surface when the airflow generating means is operated to generate a positive airflow. [13] A method of feeding a component held on a pick-up head to a pick-up surface using the component handling assembly according to any one of claims 6-12, the method comprising the steps of: Moving the receiving head holding the component towards the receiving surface so that the component is pressed against the receiving surface and the receiving surface provides a reaction force against the component which forces the foot portion of the movable member to move towards the anchor member, thereby compressing the spring member between the anchor member and the foot portion; the pickup head holding the component continues to move towards a pickup surface until the output signal of the inductive sensor increases and lies within a predefined range. [14] The method of claim 13, further comprising the steps of: detecting that the drive element has moved a distance equal to the predefined threshold distance, but the output signal of the inductive sensor is not within a predefined range; in response to this detection, the drive element is moved iteratively in predefined increments such that the pickup head is moved in corresponding predefined increments towards the pickup surface until the output signal of the inductive sensor increases and is within the predefined range.

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