GB2591071A

GB2591071A - End effector

Info

Publication number: GB2591071A
Application number: GB1914365.0A
Authority: GB
Inventors: Dean Ledger Richard; Mark Whitear Daniel
Original assignee: Millitec Food Systems Ltd
Current assignee: Millitec Food Systems Ltd
Priority date: 2019-10-04
Filing date: 2019-10-04
Publication date: 2021-07-21
Anticipated expiration: 2039-10-04
Also published as: GB201914365D0; GB2591071B

Abstract

A pneumatic end effector 2 has a carriage 4 and a first gripper 10 translatable relative to the carriage via a first pneumatic actuator 26 The gripper has a first grip means 12 to engage and grip a product between the first grip means and a second grip means 24 provided on the end effector. The first grip means is rotatable relative to the carriage via a second pneumatic actuator 60. The second actuator may have a rack and pinion with the first grip means being driven by an endless belt from the pinion. The end effector may have a second gripper 22. The grippers may have an anti-rotation feature, such as a hexagonal shaft, to prevent relative rotation between the grippers and the carriage. The end effector may be used on a robotic device such as that used on a food production line making sandwiches.

Description

End effector The present invention relates to a pneumatic end effector, particularly to a pneumatic end effector for a food production line.

According to a first aspect of the invention there is provided: a pneumatic end effector comprising: a carriage; a first gripper translatable relative to carriage via a first pneumatic actuator, the gripper comprising a first grip means configured to engage and grip a product between the first grip means and a second grip means provided on the end effector; where the first grip means is rotatable relative to the carriage via a second pneumatic actuator.

Figure 1 shows an isometric view of an end effector comprising grippers in retracted state; Figure 2 shows a side view of the end effector comprising grippers in a retracted state; Figure 3 shows an isometric view of the end effector comprising grippers in an extended state; Figure 4 shows a side view of the end effector comprising grippers in an extended state; Figure 5 shows a first section view of the end effector comprising grippers in a retracted state Figure 6 shows a first section view of the end effector comprising grippers in an extended state Figure 7 shows a second section view of the end effector.

Figure 8 shows a first isometric view of a gripper.

Figure 9 shows a third section view of the end effector comprising grippers in a retracted state Figure 10 shows a third section view of the end effector comprising grippers in an extended state Figure 11 shows a second isometric view of a gripper.

Figure 12 shows a first section view of a gripper with a gripping means in a first position.

Figure 13 shows a second section view of a gripper with the gripping means in a first position.

Figure 14 shows a first section view of a gripper with the gripping means in a second position.

Figure 15 shows a second section view of a gripper with the gripping means in a second position.

Figure 16 shows a first section view of a gripper with the gripping means in a third position.

Figure 17 shows a second section view of a gripper with the gripping means in a third position.

Figure 18 shows a section view of a second gripper with the gripping means in the third position.

Figure 19 shows the end effector attached to a delta robot Figure 20 is a close-up section view of an end effector carriage Figure 21 is a close-up isometric view of an end effector carriage shaft. Figure 22 is a close-up section view of a central hub of the end effector.

Figures 1-4 show an end effector 2 configured to grip/hold an article and provide rotation thereof. The end effector 2 is configured grip a food product, particularly a substantially flat (e.g. high aspect ratio) product, such as a sandwich.

The end effector 2 comprises a carriage 4 configured to be attached to an actuator to provide movement of the end effector 2 in use. The carriage comprises an attachment means 6 (e.g. a threaded screw or the like) to permit attachment of the end effector to the actuator. The carriage 4 comprises a plurality of connectors 8 to permit connection to a plurality of respective pneumatic lines, to a provide pneumatic power to a plurality of pneumatic actuators, as will be described below.

A first gripper 10 is movably attached to carriage 4 to provide relative movement therebetween. The first gripper 10 is movable from a retracted position where the first gripper 10 is adjacent the carriage (see figures 1 and 2) and an extended position where the gripper 12 is displaced from the carriage (see figures 3 and 4) The first gripper 10 comprises a first gripping means 12 configured to grip the product in use. The first gripping means 10 is rotatably attached to the first gripper to allow rotation of the product. The first gripping means 10 comprises an elongate channel 14 to receive the food product (e.g. the side of a sandwich). A first side wall 16 is provided on a first side of the channel. A second intermittent side wall 18 is provided on a second side of the channel. An end wall 20 is provided at an end of the channel.

A second gripper 22 is movably attached to carriage 4 to provide relative movement therebetween. The second gripper 22 is mounted at an opposing end of the carriage 4 to the first gripper 10.

The second gripper 22 comprises a second gripping means 24 configured to grip the product in use. The product is therefore gripped between the first and second gripping means. The second gripping means 24 is rotatably attached to the first gripper 10 to allow rotation of the product. It can be appreciated that the second gripper 22 shares other features common to the first gripper 22 as hereinbefore described, and hereinafter, the first and second grippers shall be referred to as "the grippers". The end effector 2 therefore can grip and flip the product.

As shown most clearly in figures 5-7, the grippers 10,22 comprise a pneumatic actuator 26 to effect movement thereof relative to the carriage 4. The grippers comprise a piston 28 received within a cavity 30 provided in the carriage 4. The cavity 30 is operatively connected to a first pneumatic connector 8 via an aperture 32, within the cavity 30 and on a first side of the piston 28. The grippers are operatively connected to the piston 28 via a shaft 34, therefore, when pneumatic pressure is applied to the cavity 30, the piston 28 is displaced outwardly, displacing the grippers outwardly. The piston 28 comprises a one or more gasket/seal 36 to provide a seal between the piston 28 and the cavity 30.

As shown in figure 7, a channel 38 is provide to effect return movement of the piston 28. The channel 38 is operatively connected to a second pneumatic connector 8 and extends into the cavity 30 on a second side of the piston 28. The channel is laterally offset from the central axis of the cavity 30. The channel 38 enters cavity 30 at a widened portion 40 thereof (note the plane section of figure 7 is laterally offset from the plane section of figures 5 and 6, hence the apparent difference in width of the cavity). Therefore, as pneumatic pressure is applied through the channel 38, the piston is displaced inwardly.

The end effector 2 therefore provides independent pneumatic actuation of the grippers 10,22 in a first outwards direction and independent pneumatic actuation in a second inward direction. In the embodiments shown in the figures, each of the grippers 10,22 is actuated simultaneously. However, in other embodiments, the grippers 10,22 may be configured to actuate independently of one another.

A stop member 42 seals the end of cavity 30, thereby maintaining a pressure seal therein and limits the movement of the piston 28. The stop member 42 comprises an aperture 44 configured to receive the gripper shaft 34. One or more seals/gaskets 46 are provided between the stop member 42 and the shaft 34/cavity walls to provide a seal therebetween.

The pneumatic actuator 26 etc. is contained within a housing provided by the carriage 4. Therefore, none of the components of the pneumatic actuator are exposed to the external environment. This prevents containments (e.g. lubricants or rubber particles from the seals) contaminating the external environment, and prevents contaminants from entering pneumatic system thereby reducing the chance of failure and/or reducing the amount of cleaning required. The carriage therefore provides a substantially hermetic barrier, and thus is particularly suitable to use in high hygiene environments, such as medical//pharmaceutical/food production environments.

Referring to figures 8-10, a connection feature is provided to operatively connect the grippers and/or prevent relative rotation between grippers 10,22 and the carriage 4. The grippers 10,22 comprise a shaft 48 extending therefrom. The shaft 48 is offset laterally offset from the pneumatic connection 26. The shaft 48 is slidably received within a cavity 50 provide on the carriage 4, thereby preventing relative rotation of the grippers 10,22 but permitting translational movement therebetween.

A common member extends between the respective shafts 48 to prevent relative rotation therebetween (e.g. a torsional rotation). Additionally or alternatively, the common member 54 provides an interconnection between the shafts 48, to prevents rocking of the shafts 48 within the carriage cavity 50 (e.g. a bending rotation).

The shaft 48 comprises a cavity 52 configured to receive the common member 54. As shown in figures 9 and 10, the common member 54 extends into the respective cavity 52 of the shaft 48 of the first gripper 10 and the second gripper 22. The common member 54 is rigidly fixed to the shaft 48 of the first gripper 10, however, the common member 54 is free to move within the cavity 52 of the shaft 48 of the second gripper 22. Such an arrangement thereby allows relative movement of the grippers 10,22 whist maintaining contact therebetween.

As shown in figure 9, the common member 54 is fixed to the shaft 48 of the first gripper 10 and is received within the shaft 48 of the second gripper 22. As shown in figure 10, after actuation of the grippers, the common member have moved along that shaft 48 of the second gripper 22, whilst still in engagement therewith.

The common member 54 is shaped to prevent rotation relative rotation thereof with respect to the shaft 48. The common member 54 comprises a polygonal cross section, for example, as shown most clearly in figure 8, a hexagonal cross-section.

Referring now to figures 11-16, the actuation of the first gripping means 12 will now be described.

The first gripper 10 comprises an elongate arm comprising an upper portion 56 and the lower portion 58. The first gripper 10 is attached to carriage proximal the upper portion 56. The first gripping means 12 is attached to the gripper 10 proximal an end of the lower portion 58 distal the upper portion 56. The first gripping means 12 is therefore separated from the carriage 4 by substantially the length of the elongate arm.

As shown in figure 12, the gripper 10 comprises a pneumatic actuator 60 configured effect rotation of the first gripping means 12. The pneumatic actuator comprises a piston 62 movably received within a cavity 64. The cavity 64 is in fluid communication with a pneumatic line connector 66 (see figure 8) configured to receive pneumatic power.

The piston 62 is operatively connected to a rack 68 (e.g. an elongate toothed member). The rack 68 operatively engages a pinion 70 (e.g. a toothed wheel), such that linear movement of the piston 62 imparts rotational movement of the pinion 70.

As shown in figure 13, the pinon 70 is operatively connected to a first wheel 72.

The first wheel 72 is in connection to a second wheel 74 via a drive loop 76 (e.g. an endless belt). The first wheel 72 and/or second wheel 74 may have teeth or the like configured to engage corresponding teeth of the drive loop 76.

The second wheel is operatively connected to the first gripping means 12. Linear movement of the pneumatic actuator 60 therefore provide rotational movement of the first gripping means. In such a configuration, movement of the pneumatic actuator is configured to rotate the first gripping means in a clockwise direction.

The pneumatic actuator 60 and drive loop 76 etc. is contained within a housing provided by the first gripper 10. Therefore, none of the components of the pneumatic actuator 60 etc. are exposed to the external environment. In a similar fashion to the carriage 4, the gripper 10 therefore provides a substantially hermetic barrier.

As shown in figures 12 and 13, the piston 62 is located in a fully retracted position. In such a position, the gripping means 12 is provided in a substantially horizontal orientation, with the first side wall 16 facing an upwards position. Pneumatic pressure is then supplied to the cavity 64, so that the piston moves toward an intermediate position shown in figures 14 and 15. In the intermediate position, the gripping means 12 is provided in a substantially vertical orientation with the end wall 20 facing upwards. Further pneumatic pressure is supplied to the cavity 64 and the piston 62 moves toward an extended position. In such a position, the gripping means 12 is provided in a substantially horizontal orientation, with the second side wall 16 facing an upwards position, as shown in figures 16 and 17.

The pneumatic actuator 60 in the gripper 10 therefore rotates the gripping means by substantially 180 degrees upon actuation thereof.

As shown in figure 18, the second gripper 22 comprises a pneumatic actuator 78 configured to rotate the second gripping means 24. The pneumatic system operates in substantially the same as described for the first gripper 10 and will not be disused further. However, the pneumatic actuator is configured rotate the second gripping means 24 in an anti-clockwise (e.g. by locating the piston 82 on an opposing side of the pinion compared with that of the first pneumatic actuator 60). The pneumatic actuators 60,78 in the grippers 10,22 are therefore configured to drive the respective gripping means in opposing rotational directions.

The pneumatic actuators 60, 78 are operatively connected such that movement of one of the gripping means imparts a corresponding movement of the other gripping means (e.g. such that they move in unison). The pneumatic actuators 60, 78 are operatively connected via the connection feature extending between the grippers 10,22. The shafts 48 of the respective grippers 10,22 are operatively connected to the to the respective pinion 70/first wheel 72. Therefore, upon rotation of the pinion 70/first wheel 72 in the first gripper 10, torque is transferred through the adjacent shaft 48, through the common member 54 and then through the distal shaft 48 on the second gripper 22, thereby rotating the pinion 70/first wheel 72 therein.

Each individual pneumatic actuator is only driven into the extended state by pneumatic power, and is returned to the retracted state by actuation of the other pneumatic actuator (e.g. by alternate actuation of the pneumatic actuators 60,78). This allows each pneumatic actuator 60,78 to only require single pneumatic feed, as retraction of the actuator is provided by the other actuation.

For example, starting with fig. 12, the piston 62 of the first gripper 10 is in the retracted state. The piston 80 of the second gripper is in the extended state. The gripping means 12,24 of both of the grippers 10,22 are in the position shown in figure 12.

The piston 62 in the first gripper 10 is driven to the extended state by pneumatic power supplied through connector 66. This rotates the first gripping means 12 and the second gripping means 24 via the connected shafts 48 to the position shown in figure 16. Simultaneously, the piston 80 in the second gripper is driven toward the retracted state.

Pneumatic power is applied to the second pneumatic actuator 78, thereby driving the piston 80 towards the retracted state. This rotates the gripping means 12,24 in the reverse direction back toward the orientation show in figure 12.

As shown in figure 19, the end effector 2 is operatively attached to a delta robot 82. The delta robot 82 comprises a plurality of articulated limbs 84 supporting an end effector carriage 83 at a lower end thereof. The end effector carriage 83 is configured to support the end effector 2. The limbs 84 are configured to pivot using motors 86 in order to translate the end effector carriage 4 in a horizontal and/or vertical direction.

The end effector carriage 83 is connected to the limbs 84 using a plurality of outstanding arms 88. The arms 88 comprise a pivotable joint 90, for example, a ball and socket joint, to allow relative rotation between the end effector carriage 83 and the limbs 84. For the sake of clarity, two limbs 84 are shown, however, it can be appreciated delta robots typically comprises three or more limbs 84. It is known that each limb 84 may comprise two parallel arms.

The delta robot 82 is positioned above/adjacent a moving conveyor 92, such as a conveyor belt system, e.g. so that the end effector carriage 83 can pick-up and/or manipulate articles 94 passing beneath the delta robot on the conveyor 92. In other examples the delta robot could be positioned above a stationary platform or a different type of conveyor. The delta robot could be used to transfer items to/from a platform or conveyor, e.g. into packaging or containers or the like.

The delta robot 82, e.g. its base and arms, may otherwise be conventional and will not be described further.

In other embodiments, the end effector is supported by an other robotic device, for example, a robotic arm, or a linear actuator.

The end effector carriage 83 comprises an external pneumatic line 96 to provide pneumatic pressure to the end effector 2 and comprises an external power line 98 to provide electrical power to the end effector 4. The pneumatic/electrical lines 96,98 may be attached to a base unit 100, or may be attached to a pneumatic/electrical source external to the system.

Figure 20 shows a close up view of an example of the end effector carriage 83.

The carriage 83 comprises a housing 102. The housing 102 surrounds the internal components of the carriage (i.e. for actuating/controlling/powering the end effector) and provides a substantially hermetic barrier between the internal environment and the external environment of the carriage 83. The housing 102 provides a sanitary barrier and prevents the ingress of, for example, dust or foodstuffs into the carriage 83.

The carriage 83 comprises an electric motor 104 disposed within the housing to provide rotational movement of the end effector 2 relative to the housing 102. The rotational movement is provided about a longitudinal axis of the carriage 83 and/or end effector 2 (i.e. such that the plane of rotation is substantially parallel to the conveyor in use 92 and/or the axis of rotation is substantially perpendicular thereto). The rotational movement of the picker provides rotational movement of the product 94, i.e. to reorient the product 94 when held by the end effector 2. The rotation may be used, for example, to align the product 94 with a package or to reorient the product 94 with respect to one or more further item on the conveyor.

The carriage 83 comprises a plurality of connectors 108 configured to connect to a respective pneumatic line 96. The connectors 108 are operatively connected to a plurality of pneumatic lines/pathways within the housing 102, generally designated as 106. The pneumatic pathways 106 provides a fluid pathway from the pneumatic line 96 through the housing interior to provide pneumatic power for actuation of the end effector 2. The pneumatic pathways 106 pass within an internal cavity alongside the motor 104, i.e. bypassing the motor which is sealed within a separate internal compartment of the housing 102.

The end effector carriage 83 and/or the end effector 2 comprises a shaft 110 operatively located in the force path between the electric motor 104 and the end effector 2 in use. The shaft 110 comprises a plurality of channels 112 extending therethrough to provide a fluid pathway between the pneumatic pathways 106 and the end effector 2 in use. Each of the channels 112 comprises at least one inlet 114. A plurality of annular chambers 116 within the housing surround a respective inlet 110, thereby permitting transfer of pneumatic fluid from the housing to the shaft, whilst rotation of the shaft is effected.

The length of channels 112 between the inlet 114 and the end of shaft 110 varies between the discrete pneumatic pathways 106. For example, a first pneumatic pathway has a channel 112 of first length, a second pneumatic pathway has a channel 112 of a second length greater than the first length, and so on. This permits spacing of the respective inlets 114 and chambers 116 along the length of the shaft 110 to maintain separation of the discrete fluid pathways between the pneumatic pathway 106 and the shaft 110.

A plurality of seals 118 are provided along the axis of the shaft 110, each of the seals 118 segregating the plurality of discrete fluid pathways between the shaft and the pneumatic pathways 106 (i.e. the seals 118 are spaced along the axis between each of the inlets 114).

The shaft 110 may comprise one or more connection features to provide a connection between the end effector 2 and the shaft 110, e.g. to provide mechanical keying of the end effector 2 and shaft 110. For example, the shaft 110 comprises a threaded hole 120 configured to receive the threaded bolt 6 on the end effector 2. Alternatively, a non-circular, e.g. elliptical or polygonal, profile of the shaft 110 and/or end effector 2 could be used to this end. Thus, the end effector 2 can be rotationally keyed to the distal end of the shaft 110, whilst permitting attachment and removal, e.g. in an axial direction, for cleaning/replacement.

As shown most clearly in figure 21, the shaft 110 comprises a plurality of outlet cavities 122 at an end thereof configured to accommodate the respective pneumatic connectors 18 on end effector 2. Each of the pneumatic lines 96/pathways 106 are operatively connected to the each of the respective. Therefore, the carriage 83 supplies the end effector 2 with pneumatic fluid to actuate each of the pneumatic actuators 26, 60, 78 independently.

For example, a first pneumatic pathway 106 is connected to the pneumatic actuator 26 configured to translate the first gripper 10; a second pneumatic pathway 106 is connected to the pneumatic actuator 26 configured to translate the second gripper 12; a third pneumatic pathway 106 is connected to the pneumatic actuator 70 configured to rotate the first gripping means 12; and a fouth pneumatic pathway 106 is connected to the pneumatic actuator 78 configured to rotate the second gripping means 24.

Referring now to figure 22, each of the pneumatic pathways 106 are provided within the end effector via a central hub 124. The central hub 124 comprises a shaft 126 received within a cavity 128 within the carriage 4. A plurality of seals 130 are provided along the axis of the shaft 126, the seals 130 providing a seal between the shaft 126 and the cavity 128. The seals 130 therefore provide a plurality of discrete cavities 132 spaced along the axis of the shaft 126. The 132 extend around the shaft 126, thus providing annular cavities accessible from any side of the shaft 126. A first cavity 132A is used to provide pneumatic power to provide the return stroke of the gripper 10,22; a second cavity 132B is used to provide pneumatic power to provide the forward stroke of the gripper 10,22 (via apertures 32). Third and fourths cavities 132C and 132C are used to provide pneumatic power to the gripping means 12,24. The use of the central hub 124 therefore allows a single connection between the end effector carriage 83 and the end effector 2 comprises a plurality of pneumatic pathways.

As more clearly shown in figure 7, one or more outlet connectors 134 may be provided to allow pneumatic connection of the central hub 124 to other locations on the end effector 2. In the present embodiment, a plurality of outlet connectors 134 are provided to allow pneumatic connection of the central hub 124 and the pneumatic connection 66 on the grippers 10,12. The outlet connectors 134 therefore allow pneumatic connections distal from the central 124, whilst still utilising the single connection between the end effector carriage 83 and the end effector 2.

The first and second grippers are substantially the same (i.e. mirror images). In other embodiments, one of the grippers is fixed/static with respect to the carriage and the other gripper moves relative thereto.

The end effector 2 and/or robot arrangement may be used in a food production line and/or as part of a food production station, particularly in a sandwich production/packaging environment. However, it can be appreciated that the apparatus may be used in any suitable environment that requires gripping and rotating of a particular product or article.

The end effector 2 provides

Claims

Claims: 1. A pneumatic end effector comprising: a carriage; a first gripper translatable relative to carriage via a first pneumatic actuator, the gripper comprising a first grip means configured to engage and grip a product between the first grip means and a second grip means provided on the end effector; where the first grip means is rotatable relative to the carriage via a second pneumatic actuator.
2. Where the pneumatic actuator comprises a piston received within a cavity.
3. Where pneumatic pressure is independently received on a first side of the piston to drive the gripper in a first direction and pneumatic pressure is received on a second side of the piston to drive the gripper in a second direction.
4. Where the second pneumatic actuator comprises a piston received within a cavity
5. Where the second pneumatic actuator comprises a rack and pinion, the rack provide on the piston and pinion is operatively connected to the first grip means, such that translation of the piston imparts a rotation to the first grip means.
6. Where the pinion and the first grip means are operatively connected via an endless belt.
7. Where the gripper comprises an anti-rotation feature to prevent relative rotation between the gripper and the carriage, the anti-rotation feature comprising a shaft provided by one of the carriage and the gripper, and a cavity configured to slidably receive the shaft provide by the other of the carriage and the gripper, the anti-rotation features offset from the first pneumatic actuator.
8. Where the end effector comprises a second gripper translatable relative to the carriage via a pneumatic actuator, the second gripper comprising the second grip means.
9. Where the second grip means is rotatable relative to the carriage via a pneumatic actuator.
10. Where the second gripper comprises an anti-rotation feature, the anti-rotation feature of the first and second grippers configured to share a common aperture provided by the carriage.
11. Where the anti-rotation features comprise a common member, where one of the first/second gripper and the common member comprises a shaft and the other of the first/second gripper and the common member comprises a cavity configured to receive the shaft.
12. Where the common member is non-circular to prevent relative rotation between the first and second gripper.
13. Where the common member is affixed to one of the first and second member.
14. Comprising a plurality of connectors for an external pneumatic line for each respective pneumatic actuator, the connectors provided on a side of the end effector distal from the first and/or second grip means.
15. Where the first and/or second gripper comprises a first member to support a first side of the product and a second member to support and second opposing side of the product.
16. A robot comprising the end effector of any preceding claim.
17. Where the end effector is operatively connected to the robot via an end effector carriage
18. Where the end effector carriage comprises a plurality of pneumatic pathways extending therethrough configured to provide pneumatic power for each of the respective pneumatic lines.
19. Where the robot is a robotic arm or a delta robot.
20. A food production line and/or workstation comprising the end effector or robot of any preceding claim.
21. Where the food production line comprises a sandwich production line.