GB2584069A

GB2584069A - Flow gripper

Info

Publication number: GB2584069A
Application number: GB1904235.7A
Authority: GB
Inventors: Dean Ledger Richard; Mark Whitear Daniel
Original assignee: Millitec Food Systems Ltd
Current assignee: Millitec Food Systems Ltd
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2020-11-25
Anticipated expiration: 2039-03-27
Also published as: GB201904235D0; GB2584069B

Abstract

A gripper assembly 16 comprising a carriage that supports a flow gripper, the flow gripper has an opening 30 to exhaust a fluid and provide a region 28 of low pressure to retain an item. A fluid pathway 32 is configured to constrain or divert a portion of the fluid away from the item. The flow gripper may be fed by a fluid source (20, fig. 3), there may be a pneumatic system 52 for drawing fluid through the exhaust system. The gripper may comprise a Bernoulli or vortex gripper. The gripper may be formed on a first side 38, where a portion of the exhaust pathway is formed on a second opposite side 42 with an outlet 46 proximal the second side. The exhaust fluid pathway 32 may be defined between inner 26 and outer 36 housings, it may be inclined 40 or annular/conical. It may be used in a food production line. A method of lifting an item using a pneumatic flow gripper is further disclosed.

Description

Flow Gripper The present invention relates to a flow gripper, particularly a flow gripper suitable for a food production environment.

INTRODUCTION

Flow grippers are commonly used in manufacturing environments where it is required to handle delicate items or workpieces, for example, silicon wafers or food products.

Figure 1 shows a prior art 'Bernoulli type' flow gripper 2. The gripper 2 is supplied with an air source 4, which is forced through a constricted aperture 6. As the air is forced through the aperture 6, the velocity of the air is increased. Due to the Bernoulli effect, this reduces the pressure of the air flowing through the aperture 6.

The airflow is directed by the aperture in an oblique direction such that it has a radially outward flow component. The speed and direction of the airflow, in turn, creates a low pressure region 8 on the underside of the gripper 2.

The parameters of the gripper (i.e. the air source 4 pressure, aperture size etc.) can be configured such that the low pressure region 8 has a lower pressure than the ambient environment. The lower pressure region 8 thus provides a lifting force 10, i.e. greater than or equal to an item 12 beneath the gripper 2, allowing the item 12 to be lifted. The lifting force 10 be tuned so that the item 12 is retained by the low pressure region 8, but need not make contact with gripper 2 body itself due to the radial airflow between the gripper and item 12. As such Bernoulli grippers may be used as minimal-contact or non-contact grippers.

Air is continually exhausted by the gripper (in contrast to a conventional suction device, in which air is drawn into the gripper). The exhaust air 14 is pushed outwards to the side of the gripper. However, to maintain a sufficiently high lifting force, a large amount of high velocity exhaust air 14 may be produced. It has been found that the exhaust air 14 can cause issues in the handling of certain types of item, or else in when used in the vicinity of other items. For example, when lightweight or thin items are required to be located in the vicinity of the gripper, those items can be dislodged or misaligned by the exhaust air 14. In a sandwich manufacturing environment in particular, the exhaust air 14 may separate the components of the sandwich.

Additionally, the exhaust air 14, may blow dirt, crumbs or other debris/particulates, which may pose hygiene or contamination issues (for example, spreading airborne pathogens or allergens).

It is an aim of the present invention to overcome or ameliorate one or more of the above problems.

STATEMENT OF INVENTION

The present invention provides a flow gripper with a means to capture and/or divert/deflect exhaust fluid of the gripper.

Flow diverting means may turn the exhaust flow away from the interface between the flow gripper and the item being lifted, e.g. towards the gripper and/or away from the item.

The flow gripper may be a pneumatic and/or non-contact gripper. The invention may be applied to a radial flow gripper, such as a Bernoulli gripper, vortex gripper, or similar.

The flow gripper may be fed by a positive pressure flow. The flow gripper may comprise a primary flow diverter, e.g. for generating the lifting force, and an exhaust flow diverter. The exhaust flow diverter may be arranged radially outside the primary flow diverter and/or may at least partially surround the primary flow diverter.

The present invention may provide a flow gripper with a means to interfere/disrupt/diffuse the exhaust fluid of the gripper.

The present invention provides a method of lifting an item comprising providing a flow gripper and diverting/capturing/intercepting at least a portion of the exhaust fluid in order to reduce the amount of exhaust fluid emitted by the gripper assembly proximal/toward an item.

Figure 1 shows a prior art non-contact gripper assembly.

Figure 2 shows a section view of a vortex/cyclone type flow gripper assembly.

Figure 3 shows a second section view of a vortex/cyclone type flow gripper assembly.

Figure 4 shows a section view of a Bernoulli type flow gripper assembly.

Figure 5 shows a second section view of a Bernoulli type flow gripper assembly.

Figure 6 shows an isometric view of a flow gripper assembly.

Figure 7 shows an exploded side view of a flow gripper assembly.

Figure 8 shows the flow through a section view of a cyclone type gripper assembly during operation.

Figure 9 shows the flow through a section view of a Bernoulli type gripper assembly during operation.

Figures 2-7 show a flow gripper assembly 16 according to embodiments of the invention.

The gripper assembly 16 comprises a flow gripper 18 configured to hold an item 12 without the item 12 making contact with the gripper assembly 16 or else with minimal/low contact pressure. The gripper 18 is actuated by a pneumatic/air system. The gripper 18 is configured to use the pneumatic system to generate a low pressure environment/region (i.e. lower than the ambient pressure) proximal the gripper 18 to provide a lift force on the item 12 sufficient to grip/hold the item 12 adjacent the gripper 18.

The gripper 18 is operatively connected to a fluid system/source 20 (shown schematically in figures 2 and 3) configured to supply a fluid to the gripper 16 to actuate the gripper 16, via a fluid connection passage 22 (shown in figure 3). The fluid may comprise one or more of: air, nitrogen, carbon dioxide, or an inert gas. The fluid connection 22 may comprise a connector 24 configured to permit the connection of a hose from the fluid source 20 to the gripping assembly.

The fluid source 20 may comprise a conventional fluid supply system and may supply fluid under positive pressure to the gripper 18. One or more valve/regulator may be used in the system to provide a selective/on-demand fluid supply.

In some embodiments, the gripper 18 comprises a cyclone/vortex type gripper (see figures 2 and 3). The cyclone gripper comprises a substantially annular cavity 28 located at a lower end thereof (i.e. proximal the item to be gripped). The cavity is open in a direction facing away from the gripper.

At least one or more flow openings 30 (i.e. inlets/nozzles) are connected to the fluid connection 22 and open into the cavity 28, such that fluid from the fluid source 20 can be released into the cavity 28. The openings 30 (individually or in combination) are narrower than the fluid connection 22 to provide a constriction of the flow area therein. Thus the opening(s) 30 accelerate the pressurised flow therethrough in use. The opening(s) 30 and/or cavity 28 are configured to generate swirl in the cavity. The openings 30 may be orientated in a direction substantially tangential to a central axis of the cavity 28 and/or walls of the cavity, in order to induce cyclonic flow of the airflow.

In other embodiments, the gripper 18 comprises a Bernoulli type gripper (see figures 4 and 5). The Bernoulli type gripper comprises one or more radially extending flow openings 30, operatively connected to the fluid connection 22, such that fluid from the fluid source 20 is configured to be released in a substantially radial direction. The flow openings 30 (individually or in combination) are narrower than the fluid connection 22 to provide a constriction of the airflow therein, i.e. to accelerate the airflow therethrough.

Both the embodiments of figures 2-3 and 4-5 may be described as radial flow grippers since they both induce a radial component of flow to induce a negative pressure region beneath the gripper. The openings 30 may be elongate passages oriented in the required direction for inducing the required radial/tangential flow. The Bernoulli type gripper could comprise a cavity 28 also, e.g. being in the form of an inverted dish or dome.

The gripper 18 itself is otherwise conventional and will not be described further.

It is appreciated the gripper is not limited to cyclone or Bernoulli type grippers, and that any conventional pneumatic/non-contact grippers that induce a lifting force by way of a directed flow (e.g. at the gripping interface) may be used.

The gripper assembly 16 comprises a carriage 26. The carriage 26 may be connected to a station of an assembly line. The station may comprises comprise a moveable member to move the carriage 26 into position proximal the item 12 to be gripped. For example, the carriage 26 may be mounted to a linear actuator, delta robot, robotic arm or similar.

The carriage 26 supports the gripper 18 and/or may provide a housing to substantially enclose the gripper 18 and/or the fluid connection 22. The gripper 18 may be detachable from the carriage 26, for example, to allow a different type of the gripper 18 to be attached.

The carriage 26 comprises a fluid pathway 32 configured to receive/intercept/capture/constrain at least a portion of the exhaust fluid from the gripper 16, and reduce the amount of exhaust fluid emitted by the gripper assembly 16 toward/proximal the item 12, thereby reducing the likelihood of damage/contamination of the item 12.

The fluid pathway 32 may be configured to capture/intercept and direct/deflect the exhaust fluid in a direction away from the item 12 and/or back towards the carriage 26. Additionally or alternatively, the fluid pathway 32 is configured to capture/intercept and direct/deflect the exhaust fluid to a location or exhaust opening remote from the item 12 or the opposing surface of the gripper/carriage (i.e. at a distance such that the force of the exhaust fluid is sufficiently diminished beneath the gripper/carriage). Additionally or alternatively, the fluid pathway 32 may interfere/disrupt the exhaust fluid flow to disperse/diffuse the exhaust fluid.

In an embodiment, the fluid pathway 32 is comprises a recessed cavity 34 in the surface of the carriage that faces the item 12 in use (e.g. the lower surface of the carriage/gripper). The recessed cavity may be configured to capture/constrain the exhaust fluid. The cavity 34 is provided in the surface of the carriage, proximal the gripper 18. The cavity 34 may surround the gripper 18 to direct the exhaust flow emitted from the gripper 18 in a radial direction, for example, to form a substantially circular cavity. In other embodiments, a plurality of (e.g. radial) cavities 34 are provided and each of the cavities 34 are located adjacent a respective exhaust outlet 30.

In either example, the cavity(s) 34 are relatively shallow, e.g. being between 0.1mm and 10 millimetres deep.

A peripheral portion 36 of the carriage may extend to a depth below/beyond the cavity 34. The gripper 18 may be recessed from the peripheral portion 36 of the carriage, such that the flow opening(s) 30 and/or a lowermost end 38 of the gripper is located within the cavity 34. In other embodiments, the lowermost end 38 of the gripper could be flush with the outer surface of the peripheral portion 36.

In any examples the opening 30 preferably does not protrude beyond the cavity 34.

The fluid pathway 32 comprises a fluid channel 40 configured to deflect the exhaust fluid away from the item 12.

In an embodiment, the fluid channel 40 is configured to deflect the exhaust fluid into the carriage 26 and/or toward a second/upper side 42 of the gripping assembly 16 and/or carriage 26. The fluid channel 40 may be operatively connected to the cavity 34 at an outer edge/extremity thereof.

The channel 40 may be inclined or curve away from the first end 36 of the gripper assembly, for example, at an oblique angle relative to a plane of the underside of the carriage and/or peripheral portion 36, e.g. at an angle of between 20-60 degrees. In this regard, the underside of the carriage and/or gripper may define an interface plane for gripping of the item 12, i.e. between the item 12 and gripper, and the channel may lead away from the interface plane.

The channel 40 may be substantially annular, for example, to form a section of a cone. In other embodiments, a plurality of channels 40 may be provided (e.g. to form a plurality of conic section sectors), and each of the plurality of channels may be circumferentially arranged about a respective cavity 34.

In other embodiments, the channel may extend substantially parallel to the interface plane and/or lower surface of the carriage 26 (i.e. radially outward from the gripper 18), such that the exhaust fluid is expelled in a radial direction from an outer edge of the carriage 26 A further channel 44 may operatively connect the channel 40 to the second side/surface 42 of the gripper assembly 16, such that the exhaust fluid can be directed out of the second side 42 of the gripper assembly and/or in a direction substantially away from the item 12. The further channel 44 may be substantially annular. The further channel 44 may be wider than channel 40 so as to cause diffusion/deceleration of the exhaust flow leaving the carriage, i.e. to act as a diffuser.

It can be appreciated that the fluid pathway 32 may deflect/direct the exhaust fluid in any direction, provided that direction reduces the amount of exhaust fluid proximal the item 12. For example, the fluid pathway may comprise outlets on a side of the carriage 26 (for example, the channel 40 may continue towards the side of the carriage), or the peripheral portion 36 of the carriage (provided they are sufficiently removed from the item). In any such examples, the exhaust outlets and exhaust passageway widens or is wider than the height of the cavity 34 so as to cause controlled diffusion of the exhaust flow.

In an embodiment, the fluid pathway 32 comprises flow guiding/inducing means 46 configured to entrain and/or draw the exhaust fluid into the fluid pathway 32. The flow inducing means 48 may further increase the amount of exhaust air captured by fluid pathway 32, e.g. by generating a negative pressure or suction within the channel 40.

The flow inducing means 46 comprises a further fluid source 48. The further fluid source 48 may comprise a fluid substantially the same as the fluid source 20 for the gripper 18, e.g. comprising one or more further fluid connection with a common fluid system.

Fluid from the further fluid source 48 is forced through a constricted aperture 50, the constricted aperture 50 opening into the fluid pathway 32 (for example, between the channel 40 and the further channel 44). In a similar fashion to the gripper 18, the fluid is accelerated through the aperture 50 to create a low pressure environment adjacent the aperture 50 and within the fluid pathway 32, thus drawing the exhaust air from the cavity 34 into and along the fluid channel 40.

The aperture 50 may be substantially annular to provide a substantially annular zone of low pressure within the fluid pathway 34. The aperture may comprise a nozzle arrangement. The aperture 50 may comprise a passageway and may be substantially radially oriented, obliquely angled or oriented away from the lower surface of the gripper, e.g. perpendicular to the surface.

As shown in figure 6, the flow inducing means 46 comprises a plurality of connectors 52 to connect the flow inducing means 46 to a plurality of fluid sources 48. The connectors 52 may be evenly distributed about the gripper 18 or about a central axis of the carriage body to evenly distribute the fluid flow therethrough.

The gripper may be defined as a primary flow diverting means for generating the 10 gripper suction, whereas the flow inducing means may be defined as a secondary flow diverting means for generating suction for the exhaust of the gripper.

In other embodiments, the fluid pathway 32 may not comprise exhaust flow induction means 46, and the exhaust fluid passively flows through the fluid pathway 32 (e.g. using the residual momentum of the exhaust fluid flow).

In some embodiments, the carriage 26 comprises an inner housing 54 located within an outer casing 56 (see figure 7). When the inner housing 54 is mounted in the outer casing 56, a gap there-between may define one or more of the flow passages (e.g. 40 and/or 44) described herein. The inner housing 54 and outer casing 56 may be correspondingly shaped to define opposing faces of a common, e.g. annular, flow passage.

The inner housing 54 supports the gripper 18, and the fluid connectors 24, 52. The inner housing may further comprise an aperture ring 58. The aperture ring 58 is located within a groove 60 located in the inner housing 54. The lower surface of the aperture ring 58 comprises a plurality of protrusions/feet 59 to create a gap between the aperture 58 and the groove 54 to define the constricted aperture 50 of the suction means 46. The protrusions 59 may be elongate in form, e.g. akin to ribs, so as to define a linear/radial flow path. The inner surface of the aperture ring 58 is larger in diameter than an outer surface of the groove 58 to provide a channel to allow flow of fluid to the aperture 50.

The inner diameter of the outer casing 56 may be larger than the outer diameter of the inner housing 54, to define a gap and delimit the fluid pathway 32 therein.

The inner housing 54 and the outer casing 56 may be joined by a plurality of bridges 62 (see figure 6).

In other embodiments, any or any combination of the fluid channels/pathways could be provided in in the form of through bores or the like extending through the carriage 26.

Operation of the invention The operation of the invention will now be described according to the cyclone gripper embodiment shown in figure 8.

Air is supplied to the gripper fluid connector 24 (for example, via a hose) under a positive pressure and travels through the fluid connection 22 (not shown) to the flow openings 30. The air is constricted by the plurality of openings 30, thus increasing the velocity of air and simultaneously reducing the pressure. As the air exits the exhaust outlets 30, the shape of cavity 28 and/or the directionality of the openings 30 causes the air to form a low pressure cyclone/vortex within the cavity 28.

The low pressure cyclone/vortex creates a low pressure region (schematically indicated at 64) proximal the gripper 18. The low pressure region is configured to have a pressure lower than the ambient pressure, thus providing a lifting force 65 to the item 12 toward the gripper 16. The pressure of the low pressure region 64 may be adjusted to provide an appropriate lifting force 65 (i.e. by adjusting the air pressure to the gripper 18 etc.).

Air is continuously supplied to the gripper 18, so that the exhaust air continuously spills' over the end 38 of the gripper 18, to create an exhaust airflow 66. The exhaust airflow travels in a radial direction away from the gripper 18 (e.g. to form a generally circular plane of airflow) and is captured/intercepted by fluid pathway 32. The fluid pathway 32 may capture between 40% and 100% of the exhaust airflow.

The exhaust airflow 66 flows in a radial direction into and along the recessed cavity 34 and is constrained/guided therein.

The exhaust airflow 66 then flows into the channel 40 and is directed/deflected away from the first end 36 of the gripper assembly 16 and the item being lifted.

Simultaneously, air 68 is provided to the flow inducing means 46 via the connector 52. The air 68 is forced through the constricted aperture 50 to provide a low pressure environment 70 within the fluid pathway 32, thus drawing the exhaust airflow 66 into the channel 40.

The exhaust airflow 66, entrained with the flow inducing means 48 airflow, flows into the further channel 44 and is exhausted at the second end 42 of the gripper assembly.

In embodiments where the flow inducing means 48 is not present/activated, it can be appreciated that the assembly will function in substantially the same way, however, the exhaust airflow 66 will passively flow through the fluid pathway 32 using the residual momentum of the airflow.

Figure 9 shows an embodiment of the invention where the gripper 18 comprises a Bernoulli type gripper.

It can be appreciated the operation of the assembly will be substantially the same as the cyclone type gripper, however, the air is exhausted by the gripper 16 in a radial direction by a plurality of radially orientated apertures 30.

The present invention provides a fluid pathway to capture and deflect/direct air exhausted by the gripper away from the item to be gripped, thus reducing the amount of airflow contacting the item and/or blowing contaminants/dust around.

This reduces/prevents damages to the item. This also prevents dust and other contaminants being either blown onto the item, or being blown into other areas of the manufacturing facility, thus reducing hygiene or contamination problems.

The present invention provides a compact gripper assembly that can be easily dismantled to allow cleaning/replacement of the assembly (for example, contaminants can easily be removed from the fluid pathway).

The gripper may be used in a food manufacturing line, e.g. for holding/positioning a food item as required. The gripper is particularly apt for lifting/picking a slice of bread for assembly of a sandwich. The gripper may be used for picking/moving other items of food having sufficient surface area to enable picking gripping in the manner described herein. For example baked items, pastry, sheet pasta and the like could also be suitable.

Claims

Claims: 1. A gripper assembly comprising: a carriage; a flow gripper supported by the carriage, the gripper comprising a flow opening configured exhaust a fluid radially outwardly from the flow opening to provide a low pressure region proximal the gripper sufficient to retain an item in use; and where the carriage comprises a fluid pathway configured to constrain and/or dived at least a portion of the exhaust fluid in a direction away from the item retained in the low pressure region.
2. A gripper assembly according to claim 1, where the flow gripper is fed by a positive pressure fluid source.
3. A gripper assembly according to claim 1, where the gripper comprises a Bernoulli or cyclone/vortex gripper.
4. A gripper assembly according to any preceding claim, where the carriage comprises opposing first and second sides, the gripper located on the first side, and where a portion of the fluid pathway extends toward the second side.
5. A gripper assembly according to claim 4, where the fluid pathway comprises an outlet proximal the second side.
6. A gripper assembly according to any preceding claim, where a portion of the fluid pathway is recessed on the first side of the carriage to provide a recessed cavity.
7. A gripper assembly according to claim 6, where the recessed cavity surrounds the flow opening and/or an end of the gripper such that the flow opening and/or gripper end is recessed from the first side of the carriage.
8. A gripper assembly according to any preceding claim, where the fluid pathway comprises a flow inducing means configured to draw exhaust fluid into the fluid pathway.
9. A gripper assembly according to claim 8, where the flow inducing means comprises a fluid source and a constricted flow outlet configured to direct flow into the fluid pathway to provide a low pressure region therein.
10. A gripper assembly according to any preceding claim, where a portion of the fluid pathway comprises a channel, the channel being inclined relative to the first side of the carriage.
11. A gripper assembly according to claim 10, where the channel is inclined at an angle of at least 20 degrees relative to the first side.
12. A gripper assembly according to any preceding claim comprising an outer casing and an inner housing within the outer casing, at least a portion of the fluid pathway defined by a gap between the inner housing and the outer casing.
13. A gripper assembly according to any preceding claim, where at least a portion of the fluid pathway is substantially annular/conical.
14. A gripper assembly according to any preceding claim, where the fluid pathway comprises a diffuser.
15. A gripper assembly according to any preceding claim, where the carriage is attached to an external actuator and/or the flow gripper is connected to a pneumatic system.
16. A food production line comprising a gripper assembly according to any preceding claim.
17. A method of lifting an item comprising: providing a pneumatic flow gripper, the gripper comprising a constricted 35 flow opening configured exhaust a fluid to provide a low pressure region proximal the gripper; positioning an item beneath the flow gripper in the low pressure region so as to lift to the item and retain the item adjacent the flow gripper; and diverting at least a portion of the exhaust fluid in order to reduce the amount of exhaust fluid emitted by the gripper assembly toward the item.
18. A method according to claim 17, where the gripper comprises a Bernoulli gripper and/or a cyclone/vortex gripper.
19. A method according to claim 17 or 18, comprising deflecting/directing the exhaust fluid in a direction radially and/or upwardly away from the item.
20. A method according to any of claims 17-19, comprising deflecting/directing the exhaust fluid to an exhaust opening remote from the item.
21. A method according to any of claims 17-20, comprising de-energising/diffusing the exhaust fluid flow to disperse the exhaust fluid.