Interchanging of gripper fingers

Abstract

Device comprising a functional gripper head with a plurality of gripper fingers which are connected to guides and are thus displaceable for gripping with the functional gripper head, wherein the guides each have a guide block and wherein the gripper fingers each have proximally a finger base, wherein each guide block and each finger base has compatible connecting means for connecting the guide blocks to corresponding gripper fingers, which connecting means comprise an opening and a pin which fits in the opening and which is movable into and out of the opening via a movement in a first direction, wherein the pin and opening further comprise a locking mechanism which is provided in spring-loaded manner in order to, in rest, push the locking mechanism to a locked position wherein the pin is held in the opening, wherein the finger base further has an engaging edge, which locking mechanism has a projection which is movable in said first direction in order to push the locking mechanism to an unlocked position.

Description

[0001] Interchanging of gripper fingers

[0002] The invention relates to a device comprising a functional gripper head with a plurality of gripper fingers which are provided in guides and are thus displaceable to grip with the functional gripper head, wherein the guides have guide blocks which are connectable to corresponding gripper fingers.

[0003] A functional gripper head is typically provided on a robot or on an operating device that must be able to grip objects. Because objects can vary in size and shape, flexibility of the functional gripper head is important.

[0004] A device with a flexible functional gripper head is known from WO2021165800 by the same applicant, and relates to the same basic problems. This document describes a functional gripper head equipped with a plurality of displaceable gripper fingers. These gripper fingers are mounted in guides which are provided with compatible guide blocks. The movement of the gripper fingers is regulated by a mechanism with a helical gear, which converts a rotation movement into a linear movement. The gripper head is interchangeable by means of a removable segment comprising both the gripper fingers and the guide plate. Making the gripper head interchangeable enables both small objects and large objects as well as objects with different shapes to be gripped optimally by the plurality of gripper heads. The positioning and the number of fingers can here vary from gripper head to gripper head. The construction of this gripper head makes this gripper head ideal for heavier applications. The structure of this gripper head also tends to be more complex, and thereby expensive.

[0005] Another device is known from EP4215319, in which a system is described for interchanging gripper fingers of the gripper head. The system comprises a gripper head and a finger which can be attached to the gripper head, and a storage space for storing the fingers. The gripper head or the finger has a locking pin which moves between an unlocking position and a locking position. In the unlocking position the gripper head can be released from the finger, while in the locking position it can be locked to the finger by the locking pin. The finger can be placed in the storage space, wherein an operating mechanism in the storage space pushes the locking pin out of the locking position when the finger is placed in the storage space. The construction of this gripper head makes this gripper head ideal for lighter applications. The structure of this gripper head tends to be simpler, and thereby cheaper.

[0006] It is an object of the invention to find a flexible functional gripper head which is inexpensive and is suitable for lighter applications.

[0007] For this purpose the invention provides a device comprising a functional gripper head with a plurality of gripper fingers which are connected to guides and are thus displaceable for gripping with the functional gripper head, wherein the guides each have a guide block and wherein the gripper fingers each have proximally a finger base, wherein each guide block and each finger base has compatible connecting means for connecting the guide blocks to corresponding gripper fingers, which connecting means comprise an opening and a pin which fits in the opening and which is movable into and out of the opening via a movement in a first direction, wherein the pin and opening further comprise a locking mechanism which is provided in spring-loaded manner in order to, in rest, push the locking mechanism to a locked position wherein the pin is held in the opening, wherein the finger base further has an engaging edge, which locking mechanism has a projection which is movable in said first direction in order to push the locking mechanism to an unlocked position.

[0008] A gripper head with gripper fingers is designed to grip objects of different shapes and sizes, often used in robots or other operating devices. The gripper fingers are displaceable in that they are provided in guides. The maximum movement of the gripper fingers, and thus the variety of objects that can be gripped, is limited by the freedom of movement of the guides. To increase this variety, and thereby make the gripper head more flexible, the fingers are interchangeable. For this purpose each guide has a guide block to which a gripper finger can be connected. Each finger has a finger base which is compatible with the guide block. More specifically, the finger base and the guide block have compatible connecting means with a pin that fits in an opening. The finger can hereby be connected to the guide by a movement in a first direction, this being the direction in which the pin can move into and out of the opening.

[0009] In order to facilitate placing and removing of fingers on and from the guides each finger base is provided with an engaging edge. This engaging edge can for instance be engaged by a set-down station or other device and so hold the finger base and thus also the finger. Further provided is a projection which is displaced when the engaging edge is engaged. More specifically, the projection is connected to a locking mechanism of the connecting means. When connecting to the connecting means, the pin is inserted into an opening. The locking mechanism is compatible with the pin and the opening such that, when the locking mechanism is in the locked position, the pin is held in the opening. When the locking mechanism is in the open position, movement of the pin into and out of the opening is possible. The projection is connected to the locking mechanism in order to push the locking mechanism to the open position. The projection is further spring-loaded directly or indirectly so that the locking mechanism moves to the locked position in unloaded state of the projection.

[0010] At least in the open position of the locking mechanism, the pin is movable relative to the opening in a first direction in order to move the pin into and out of the opening and so connect the finger to and uncouple it from the guide. The projection is movable in the same first direction, and an improved and / or alternative manner of providing an interchangeable finger on a gripper head is thus provided. More specifically, tests and simulations have shown that the locking mechanism can be provided in extremely simple manner and that the movement during connecting and uncoupling of the finger to and from the guide can take place in a natural and simple manner.

[0011] Engaging of the finger base can be done both manually and automatically, depending on the specific requirements of the application. The automatic method is described in detail below. It will however be apparent that this is only a preferred method, and that it is possible for an operator of the machine with the functional gripper head to engage the finger base, preferably with a tool, in order to remove the finger base from the guide. A different gripper finger can also be provided on the guide manually.

[0012] The construction of the functional gripper head according to the invention is simple and can thereby be realized inexpensively, and is suitable for lighter applications. It will however also be possible to use this construction in an efficient manner in heavy applications. The use is therefore not limited to the lighter applications.

[0013] Preferably, the opening is provided in the guide block and the pin and the projection are provided on the finger base, wherein the locking mechanism is provided in the finger base and the pin, and wherein the projection is situated close to the engaging edge. This construction provides a compact and reliable mechanical structure of the guide and the gripper fingers.

[0014] Preferably provided in the pin is a shaft which extends between the projection and the locking mechanism in order to transmit a movement of the projection to the locking mechanism. A shaft provided in the pin is a simple mechanical way of driving a locking mechanism with a projection. The shaft can also be spring-loaded in simple manner in order to press the locking mechanism to the locked position in rest. This is possible because the direction of movement of the pin relative to the opening is equal to the direction of movement of the projection.

[0015] The engaging edge is preferably formed by a blind groove extending transversely of the first direction and extending at least partially in a displacement direction of the gripper finger in the guide. A blind groove can be engaged in simple manner by a set-down station or other device. By forming the blind groove in a displacement direction of the gripper finger in the guide it becomes possible in simple manner to move the finger base in a set-down station or other device by a movement of the guide. No moving parts are hereby necessary on the set-down station or on the other device to engage the finger base on the engaging edge. This makes the whole simple and inexpensive.

[0016] The projection is preferably situated in the blind groove, such that a centre of gravity of the projection is situated above a centre of the blind groove. When the centre of gravity of the projection is situated above a centre of the blind groove, the groove will typically be pushed upward when a set-down station or other device engages or slides into the blind groove. The projection will hereby push the locking mechanism to an open position. An additional advantage of moving the projection into and out of the opening in the same direction as the pin is that the projection holds the position of the blind groove relative to the set-down station by clamping. This makes gripping of the finger base operationally reliable and dependable. The force is manifest at an extremely short distance, i.e. between an edge of the blind groove and the projection situated in the blind groove, via the engaging element. This in contrast to the projection being moved in a different direction and thereby always pushing the engaging element away from the finger base, which would be detrimental to the reliability.

[0017] The device preferably further comprises a set-down station for the gripper fingers, which set-down station comprises for each gripper finger of the functional gripper head a fork which is compatible with the engaging edge in order to hold the gripper finger when the fork engages on the engaging edge. The fork has prongs which fit in the blind groove, so that the one prong is situated in the blind groove on the one side of the finger base and the other prong is situated in the blind groove on the other side of the finger base. The finger base thus comes to he between the two prongs of the fork, wherein the prongs engage in the blind groove. The prongs then typically push against the projection to operate the locking mechanism.

[0018] A distal end of the fork is preferably wedge-shaped in order to move the projection in the first direction when the fork engages on the engaging edge. The wedge shape makes operation of the projection simple.

[0019] The fork preferably has a recess for the projection in an end position of the fork relative to the engaging edge when the fork engages on the engaging edge, which recess allows the projection to move to the locked position to limited extent. The projection is spring-loaded to the locked position. The projection will hereby always tend to move to the locked position. This tendency can be used, by providing the recess in the fork, to hold the finger base in place on the fork. This is because the position of the finger base relative to the fork is fixed in that the projection is pressed into the recess. The spring force of the projection can thus be used to hold the position of the finger base relative to the set-down station in a predetermined location. The locking mechanism preferably allows for free movement of the pin relative to the opening here when the projection is in the locked position to limited extent.

[0020] Preferably, the pin has a tapered shape, and a distal and a proximal segment of the pin has a diameter corresponding with the opening in the corresponding guide block in order to form a close fit. The close fit enables a precise positioning of the finger relative to the guide to be obtained. The functional gripper head can hereby function precisely, this being advantageous for instance when it is provided on a robot or other operating device.

[0021] Each guide block preferably has at least one venting channel which extends between the opening and an outer surface of the guide block. Due to the close fit of the diameter of the pin and the diameter of the opening in the guide block, it is difficult for air to escape when the pin is moved into the opening, and a partial vacuum may be created when the pin is moved out of the opening. Providing one or more venting channels makes it simpler to move the pin into and out of the opening, even with an extremely close fit.

[0022] In addition to the pin and opening, each finger base and corresponding guide block preferably further has a compatible recess and protrusion for fixing an angular orientation between the finger base and the corresponding guide block when the finger base is connected to the guide block. The recess and the protrusion are preferably provided outside an outer periphery of the pin. The recess and the protrusion are hereby positioned eccentrically relative to the pin and the opening. When the protrusion is compatible with the recess, i.e. the protrusion fits closely in the recess in the mounted state of the finger in the guide, the angular position of the finger relative to the guide will thereby be fixed. Only one pin and one opening is thereby needed per finger. In this context it will be apparent that it is alternatively possible to provide a plurality of pins per finger when the application requires it. The guide block will then have a plurality of corresponding openings. In that case a recess and compatible protrusion are not necessary because the relative position between finger base and guide block can be held unequivocally by the plurality of pins.

[0023] The invention further relates to a method for interchanging a gripper finger of a guide of a functional gripper head, wherein the method comprises of:

[0024] - engaging a finger base of the gripper finger on an engaging edge, such that a projection of the finger base is moved in a first direction;

[0025] - moving a pin of the finger base from a fitting opening of a guide block of the guide in the first direction in order to interchange the gripper finger of the guide;

[0026] wherein the projection is connected to a locking mechanism in the pin which is provided in spring -loaded manner in order to push the locking mechanism to the locked position in rest, wherein the opening in each of the guide blocks further has a locking edge which is compatible with the locking mechanism, such that the pin is held in the opening in the locked position of the locking mechanism.

[0027] The method allows fingers of a functional gripper head to be interchanged in an efficient manner, this greatly improving the flexibility of the functional gripper head. The advantages and effects described at length above similarly apply to the method.

[0028] Preferably, a set-down station for the gripper fingers is further provided, which setdown station comprises for each gripper finger of the functional gripper head a fork which is compatible with the engaging edge, and the method further comprises of:

[0029] - positioning the functional gripper head relative to the set-down station, such that the engaging edge lies in line with the fork; and - moving the finger base with the engaging edge in the fork so that the finger base is enclosed at least partially by prongs of the fork.

[0030] Preferably, prongs of the fork have a wedge-shaped point, and the method comprises of:

[0031] - moving the projection in the first direction by pushing the wedge-shaped point under the projection while the fork moves in a blind groove which forms the engaging edge.

[0032] This method makes it possible to interchange gripper fingers efficiently, which considerably increases the flexibility of the gripper head. This results in an improved operational efficiency and a reduction in downtimes. The presence of a set-down station for the gripper fingers further contributes to organized and safe management of the gripper fingers.

[0033] The invention will now be further described on the basis of one or more exemplary embodiments shown in the drawings.

[0034] In the drawing:

[0035] figure 1 shows an exemplary application of a functional gripper head according to an embodiment of the invention;

[0036] figures 2A and 2B show parts of an exploded view of a functional gripper head according to an embodiment of the invention;

[0037] figures 3A - 3D show the steps for removal of the gripper fingers from the functional gripper head according to an embodiment of the invention;

[0038] figure 4 shows a cross-section of a gripper finger of a functional gripper head according to an embodiment of the invention;

[0039] figure 5 shows an embodiment of a set-down station;

[0040] figure 6 shows a detailed embodiment of a pin in an opening according to an embodiment of the invention; and

[0041] figure 7 shows an opening with protrusion according to an embodiment of the invention.

[0042] The same or similar elements are designated in the drawing with the same reference numerals.

[0043] Figure 1 shows a functional gripper head 1 on a robot arm 26. A functional gripper head 1 is a mechanical part which is often used on robots or operating devices such as lathes, CNC machines and the like in order to grip and displace objects. The functional gripper head 1 is equipped with a plurality of gripper fingers 2, which are mounted in guides 3. These guides 3 have guide blocks 4 in which the gripper fingers 2 are mounted replaceably, whereby the gripper head 1 is adaptable to different shapes and sizes of object.

[0044] The gripper fingers 2 are connected via the guides 4 to a mechanism which controls their movement. A very common mechanism uses a helical gear (not shown) to convert rotation movements into linear movements, which ensures an accurate and controlled movement of the fingers. Owing to this accurate and controlled movement, the gripper head can pick up, displace and release objects in safe and efficient manner.

[0045] Mechanisms other than a helical gear are likewise applicable in the context of this invention. The use of such a mechanism is only an example, and is not essential for operation of the gripper head 1. Different alternative driving techniques can be utilized without having any adverse effect on the functionality and versatility of the functional gripper head 1 according to the invention.

[0046] Shown in figures 1 and 2 are configurations of a functional gripper head 1 wherein the gripper head 1 has three gripper fingers 2. Shown in further figures are configurations of a functional gripper head 1 wherein the gripper head 1 has two gripper fingers 2. The operating principle of these different configurations is analogous, and a gripper head 1 can be provided with two or more gripper fingers having the same or a different size and shape. Each of these gripper fingers 2 can be interchanged according to the principles explained in this description.

[0047] The gripper fingers 2 are each provided on a finger base 5. Each finger base 5 is provided with connecting means 6 in order to be connected interchangeably to a corresponding guide block 4. This provides for a greater flexibility of the functional gripper head 1. This is because fingers 2 with different shapes and different positions on the finger base 5 can be provided on the functional gripper head 1. This enables gripper fingers to be placed close together on the gripper head, whereby small objects can be clamped, or enables gripper fingers to be placed far apart on the gripper head, whereby larger objects can be clamped. Gripper fingers 2 are closer together when the position of the finger on the finger base 5 lies closer to a centre of the gripper head in a position of the finger base 5 in which it is mounted on the functional gripper head 1. The skilled person will appreciate that different finger positions and forms of fingers 2 can be provided in order to achieve an optimal result, depending on the intended application.

[0048] Figure 2A shows a functional gripper head 1 as in figure 1, where the three finger bases 5 and gripper fingers 2 have been removed from their respective guide blocks 4 and guides 3. In the shown embodiment each guide block 4 has an opening 7 and a protrusion 25. This opening 7 and protrusion 25 together form the connecting means 6 whereby the guide block 4 can connect to a finger base 5 with compatible connecting means 6. Each guide block 4 can move in its respective guide 3, designated with arrows 27. These arrows 27 indicate the gripping movement of the functional gripper head 1.

[0049] Figure 2B shows a schematic outline of a gripper finger 2 on a finger base 5, adapted to be connected to a guide block 4 of figure 2A. In practice, three of the gripper fingers 2 shown in figure 2B will be provided to connect to the three guide blocks 4 of figure 2A. In order to connect the finger base 5 to the guide block 4, finger base 5 is provided with compatible connecting means 6. In the shown embodiment these connecting means 6 comprise a pin 8 and a recess 24. The skilled person will appreciate that a reverse construction, wherein the pin is for instance provided on the guide blocks and the opening is provided in the finger base, is also possible. The skilled person will also appreciate that the recess 24 and the protrusion 25 can be switched around.

[0050] Figure 2B further shows that the finger base 5 has an engaging edge 12 whereby finger base 5 can be held. In the embodiment of figure 2B the engaging edge 12 takes the form of a blind groove 15. The skilled person will appreciate that other possible configurations are also possible, for instance wherein the engaging edge takes the form of an edge protruding from finger base 5.

[0051] Figure 2B shows pin 8 eccentrically. Placing pin 8 centrally, and providing a second recess 24 opposite the shown recess 24, provides an additional option of placing finger base 5 on the guide in two orientations. This would allow the finger base 5 to be placed on the guide with the finger 2 on an outer side of finger base 5, and finger base 5 to be placed on the guide with the finger 2 on an inner side of finger base 5.

[0052] Figures 3A-3D show the steps of interchanging a gripper finger. The skilled person will appreciate that the order of steps from figure 3A to figure 3D can be followed in order to remove gripper fingers, while a reverse order of steps from figure 3D to figure 3A can be followed in order to connect gripper fingers. In order not to make the description needlessly complicated, the figures 3A-3D will be described below in the order as shown, to remove gripper fingers. Figures 3A-3D show a configuration with two gripper fingers 2 on the functional gripper head 1, since this is easiest to show in a figure. The skilled person will appreciate that the same principles can be applied to interchange more gripper fingers 2.

[0053] Figure 3 A shows the set-down station 16, wherein a set-down fork 16 is provided for each gripper finger 2. The gripper head with the guides 3 and the gripper fingers 2 are not positioned in line with the set-down station 16. In the method for removing gripper fingers, the functional gripper head 1 will be moved 29 to the set-down station 16. Each gripper finger 2 is positioned on a finger base 5 which is connected to a guide block 4. The guide block 4 can move in the guide 3. When moving the functional gripper head 1 to the set-down station, the gripper fingers 2 are preferably moved inward to maximum extent. Hereby, gripper fingers 2 fit with their finger bases 5 between the forks 16 of the set-down station. Also provided on each finger base 5 is a projection 13. Each finger base 5 also has a blind groove 15 with the engaging edge by which the finger base can be gripped and held. The blind groove 15 is preferably provided on either side of each finger base 5 and compatible with the fork 16 of the set-down station, such that the space between the prongs of the fork is substantially the same as the space between two opposite blind grooves 15. The thickness of the prongs of the fork 16 is also substantially the same as the width of the blind grooves 15, so that the prongs of the fork 16 fit into the blind grooves. The function and action of the projection will be discussed in further detail below.

[0054] Figure 3B shows the same elements as figure 3A, but in a position in which the blind grooves 15 are aligned with the forks 16 of the set-down station. This allows the gripper fingers 2 to move with their finger bases 5 to an open position, as indicated with arrow 27. Owing to this movement, the finger bases 5 come to lie with their blind grooves 15 in the forks, as shown in figure 3C. As the finger bases 5 move with their blind grooves 15 into the forks, the projection 13 is also operated, as will be discussed in further detail below.

[0055] Figure 3C shows that each finger base 5 has been gripped by a fork 16 of the setdown station. In this stage the finger base 5 is also uncoupled from the guide block 4 because the projection 13 has been moved. This allows the functional gripper head to move away from the setdown station 16, as shown in figure 3D. The gripper fingers 2 thereby remain with their finger bases 5 in the set-down station 16, and the functional gripper head 1 can be provided with different gripper fingers 2.

[0056] Figures 3A-3D show that the set-down station 16 can be formed completely passively and that the standard movement of the functional gripper head, i.e. the gripper movement 27, can be used to interchange the gripper fingers. The skilled person will appreciate that, in situations or machines where the functional gripper head cannot move in the space as with a robot arm, it is possible to move the set-down station to the functional gripper head 1. Gripper fingers can thus for instance be interchanged on a lathe or CNC machine.

[0057] Figure 4 shows a schematic construction of the locking mechanism 10 according to a preferred embodiment of the invention. The shown locking mechanism 10 is primarily formed in the pin 8 and the finger base 5. Provided in the core of pin 8 are balls which can be pressed partially outward by a shaft 14. Pressing outward enables the balls to engage behind a locking edge 28 which is provided in the opening 7, see figure 6. This position of the balls and the locking mechanism 10 is referred to as the locked position. The shaft 14 is spring-loaded with a spring 11 to push the shaft 14 down and thereby push the locking mechanism 10 to the locked position. In rest or in unloaded state the locking mechanism 10 will hereby always be in the locked position. The skilled person will appreciate that, in the shown construction, the balls can be replaced with cylindrical rollers, needle rollers or other locking elements which are movable between the locked position and the unlocked position. The shaft 14 has a wedge, also shown as a ball in figure 4, for pressing the locking elements apart in the locked position. This wedge can also be formed by wedge elements other than balls.

[0058] Figure 4 shows that the pin 8 has distally a tapered end 20. This tapered end 20 makes it easier to insert a pin 8 into an opening 7. Figure 4 shows that projection 13 is connected to the shaft 14. By moving the projection 13 upward, see arrows 9, the shaft 14 is moved upward, this being counter to the direction of spring 11. This will bring the locking mechanism into the unlocked position. This is because the balls can move inward into the pin and come to he at least largely inside the periphery of the pin 8. When the projection 13 is released, the spring 11 will push the shaft 14 downward once again in order to push the balls outward and so bring the locking mechanism into the locked position.

[0059] Figure 4 shows the projection 13 essentially schematically, and the ratios and sizes of parts will be different in practice. This figure serves only to elucidate the operating principle of the projection. A primary aspect of the locking mechanism 10 is that the projection 13 unlocks the locking mechanism 10 when the projection 13 is moved in the first direction 9. The first direction 9 is the direction in which pin 8 extends and is thus also the direction in which pin 8 can be moved into and out of the opening 7. In other words, the direction of movement for the locking mechanism is identical to the direction of movement of the interchanging of the gripper fingers 2. In order to realize this in an optimal manner the projection is provided in the blind groove 15. The diameter of the projection is here either smaller than the blind groove 15, or a centre of gravity of the projection is provided above a centre of the blind groove 15, or an underside of the projection is provided above the lower edge of the blind groove 15. Owing to this positioning of the projection 13 relative to blind groove 15, a wedge-shaped prong will always move the projection upward and so unlock the locking mechanism 10 when this wedge-shaped prong of a set-down station, see figure 5, slides through the blind groove 15. The skilled person will appreciate that other mechanisms can also be provided to unlock the locking mechanism via a projection 13. The locking mechanism can also be constructed differently, for instance by providing a shaft in the guide block 4 adjacently of the opening for gripping pin 8.

[0060] Figure 5 shows an additional aspect of the unlocking of the locking mechanism. More specifically, figure 5 shows the projection 13 in multiple positions relative to the fork 16 of the set-down station. The fork has a prong 17 with a wedge-shaped point 18. Figure 5 further shows that the prong 17 has a recess 19 which the projection 13 can fall into when the finger base 5 reaches its end position in the set-down station. The recess 19 has a depth here for moving the projection toward the locked position to some extent, but not far enough for the locking mechanism to effectively close. In this way the spring force of the locking mechanism can be used to hold the finger base 5 in its end position in the set-down station. This increases the reliability and stability of the system as a whole.

[0061] Figure 6 shows a section of a specific embodiment of a pin 8 in an opening 7 of a guide block 4. The pin 8 is connected to a finger base 5. Provided in the pin 8 is a shaft 14 which pushes against balls of a locking mechanism 10. More specifically, the balls of the locking mechanism 10 are pushed outside the periphery of the pin 8 so as to engage in a locking edge 28 which is provided in the opening. The skilled person will appreciate that when the locking mechanism 10 is in the locked position, it is impossible to remove the pin 8 from the opening 7. Figure 6 further shows the projection 13.

[0062] Figure 6 shows that both the pin 8 and the opening 7 have a stepped form in order to have on one hand distally and proximally a segment where the pin 8 fits closely in the opening 7, and on the other still allow for easy movement of pin 8 in the opening 7. The figure shows that the pin has at the distal outer end a tapered segment 20. In this embodiment the locking mechanism is provided adjacently of this tapered segment 20. Further provided distally is a closely fitting segment 21 whereby the pin 8 can be positioned precisely in the opening 7. The pin also has a closely fitting segment 22 proximally. The diameter of the closely fitting proximal segment 22 is greater than the diameter of the closely fitting distal segment 21. This makes the pin slightly tapered over its whole length, whereby the pin can be inserted into the opening in simple manner and can still be positioned in the opening very accurately both proximally and distally owing to the close fit. Alternatively, a suitable diameter can be provided for positioning the pin accurately in the opening, without a stepped design with different diameters proximally and distally.

[0063] Figure 7 shows the opening 7 in the guide block 4. The locking edge 28 is shown here. Also shown is that venting channels 23 are preferably formed between the opening 7 and a periphery of the guide block 4. Air can flow out of and into the opening through the venting channels 23 when a pin 8 is moved into and out of the opening. This is because, owing to the close fit, see figure 6, air is trapped in the opening when the pin moves into the opening. The venting channels 23 simplify placing and removal of a pin.

[0064] Figure 7 further shows a specific embodiment of a protrusion 25. As already described above, this protrusion 25 is compatible with a recess 24 of the finger base such that the protrusion 25 fits in the recess 24 when the finger base 5 is placed on the guide block 4. The protrusion 25 and the recess 24 prevent rotation of the guide block 4 relative to the finger base 5. Owing to the combination of pin 8 and opening 7 on one hand and protrusion 25 and recess 24 on the other, the relative end position of guide block 4 and finger base 5 is unequivocally fixed. The fit between pin 8 and opening 7 on one hand and protrusion 25 and recess 24 on the other allows for an accurate positioning of guide block 4 relative to finger base 5. The protrusion 25 and the recess 24 have complementary tapering forms in order to simplify engaging of the protrusion 25 in the recess 24. Alternatively, the protrusion can be formed by a round pin, preferably with a tapered head. The recess can then take the form of a corresponding round opening.

[0065] The above described exemplary embodiments serve solely for the purpose of illustrating the invention and are not intended to limit the scope of protection.

[0066] List of shown elements and corresponding reference numerals: Functional gripper head 1 Gripper fingers 2 Guides 3

[0067] Guide block 4

[0068] Finger base 5 Connecting means 6 Opening 7

[0069] Pin 8

[0070] first direction 9

[0071] locking mechanism 10 spring 11

[0072] engaging edge 12 projection 13

[0073] shaft 14

[0074] blind groove 15

[0075] set-down station 16 fork 17

[0076] wedge shape 18

[0077] recess 19

[0078] tapered end pin 20 distal segment pin 21 proximal segment pin 22 venting channel 23 recess 24

[0079] protrusion 25

[0080] robot 26

[0081] gripping movement 27 locking edge 28 movement 29

Claims

Claims1. Device comprising a functional gripper head with a plurality of gripper fingers which are connected to guides and are thus displaceable for gripping with the functional gripper head, wherein the guides each have a guide block and wherein the gripper fingers each have proximally a finger base, wherein each guide block and each finger base has compatible connecting means for connecting the guide blocks to corresponding gripper fingers, which connecting means comprise an opening and a pin which fits in the opening and which is movable into and out of the opening via a movement in a first direction, wherein the pin and opening further comprise a locking mechanism which is provided in spring-loaded manner in order to, in rest, push the locking mechanism to a locked position wherein the pin is held in the opening, wherein the finger base further has an engaging edge, which locking mechanism has a projection which is movable in said first direction in order to push the locking mechanism to an unlocked position.

2. Device according to claim 1, wherein the opening is provided in the guide block, wherein the pin and the projection are provided on the finger base, wherein the locking mechanism is provided in the finger base and the pin, and wherein the projection is situated close to the engaging edge.

3. Device according to claim 2, wherein provided in the pin is a shaft which extends between the projection and the locking mechanism in order to transmit a movement of the projection to the locking mechanism.

4. Device according to any one of the foregoing claims, wherein the engaging edge is formed by a blind groove extending transversely of the first direction and extending at least partially in a displacement direction of the gripper finger in the guide.

5. Device according to claim 4 and claim 2 or 3, wherein the projection is situated in the blind groove, such that a centre of gravity of the projection is situated above a centre of the blind groove.

6. Device according to any one of the foregoing claims, further comprising a setdown station for the gripper fingers, which set-down station comprises for each gripper finger of the functional gripper head a fork which is compatible with the engaging edge in order to hold the gripper finger when the fork engages on the engaging edge.

7. Device according to the foregoing claim and at least claim 2, wherein a distal end of the fork is wedge-shaped in order to move the projection in the first direction when the fork engages on the engaging edge.

8. Device according to claim 7, wherein the fork has a recess for the projection in an end position of the fork relative to the engaging edge when the fork engages on theengaging edge, which recess allows the projection to move to the locked position to limited extent.

9. Device according to the foregoing claim, wherein the locking mechanism allows for free movement of the pin relative to the opening when the projection is in the locked position to limited extent.

10. Device according to any one of the foregoing claims, wherein the pin has a tapered shape and wherein a distal and a proximal segment of the pin has a diameter corresponding with the opening in the corresponding guide block in order to form a close fit.

11. Device according to the foregoing claim, wherein each guide block has at least one venting channel which extends between the opening and an outer surface of the guide block.

12. Device according to any one of the foregoing claims, wherein in addition to the pin and opening, each finger base and corresponding guide block further has a compatible recess and protrusion for fixing an angular orientation between the finger base and the corresponding guide block when the finger base is connected to the guide block.

13. Method for interchanging a gripper finger of a guide of a functional gripper head, wherein the method comprises of:- engaging a finger base of the gripper finger on an engaging edge, such that a projection of the finger base is moved in a first direction;- moving a pin of the finger base from a fitting opening of a guide block of the guide in the first direction in order to interchange the gripper finger of the guide;wherein the projection is connected to a locking mechanism in the pin which is provided in spring -loaded manner in order to push the locking mechanism to the locked position in rest, wherein the opening in each of the guide blocks further has a locking edge which is compatible with the locking mechanism, such that the pin is held in the opening in the locked position of the locking mechanism.

14. Method according to the foregoing claim, wherein a set-down station for the gripper fingers is further provided, which set-down station comprises for each gripper finger of the functional gripper head a fork which is compatible with the engaging edge and wherein the method further comprises of:- positioning the functional gripper head relative to the set-down station, such that the engaging edge lies in line with the fork; and- moving the finger base with the engaging edge in the fork so that the finger base is enclosed at least partially by prongs of the fork.

15. Method according to the foregoing claim, wherein prongs of the fork have a wedge-shaped point and wherein the method comprises of:- moving the projection in the first direction by pushing the wedge-shaped point under the projection while the fork moves in a blind groove which forms the engaging edge.

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