GB1589426A

GB1589426A - Transfer mechanism eg a vacuum starwheel

Info

Publication number: GB1589426A
Application number: GB33705/77A
Authority: GB
Original assignee: Industrial Dynamics Co Ltd; IND DYNAMICS CO Ltd
Current assignee: Industrial Dynamics Co Ltd; IND DYNAMICS CO Ltd
Priority date: 1976-11-04
Filing date: 1977-08-11
Publication date: 1981-05-13
Also published as: DE2738570A1; DE2738570C2; JPS5357668A; CA1109026A

Description

(54) A TRANSFER MECHANISM, E.G. A VACUUM STARWHEEL (71) We, INDUSTRIAL DYNAMICS COM- PANY, LTD., a corporation organised and existing under the laws of the State of California, United States of America, with offices at 2927 Lomita Boulevard, Torrance, County of Los Angeles, State of California, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to a transfer mechanism for transferring objects from one infeed position selectively to one of at least two outfeed positions.

An example of such a transfer mechanism is a vacuum starwheel for diverting containers, such as bottles, into one of a number of conveyor lines. It is a common practice to have a plurality of containers, such as bottles, moved down a conveyor line to a station for inspection of the container for either various types of defects or for segregation between different types of containers. The bottles enter into and are engaged by the vacuum starwheel which generally moves the bottles along a circular path, with each bottle contained within a separate Pocket of the starwheel, and with the bottles then deposited onto a specific one of a plurality of outfeed lines in accordance with the previous inspection.

For example, if the inspection is to determine contamination of the bottles, one outfeed line may represent rejects and another line may represent acceptable bottles. If, for example, the inspection is to segregate the containers, such as bottles, according to shape, one outfeed line may represent bottles of one shape and the other outfeed line may represent bottles of another shape, or there may even be a plurality of outfeed line representing bottles of different shapes. In addition, the vacuum starwheel may be used merely to subdivide a large plurality of containers, such as bottles, from an infeed conveyor line to a plurality of outfeed conveyor lines.

Generally, the vacuum starwheel includes a plurality of suction cups each connected by a tube to a source of vacuum. Various combinations of applying vacuum or releasing vacuum to a particular suction cup determines the final destination of the container in contact with that cup.

As one particular example, a prior art system would apply vacuum through a suction cup to the container, such as a bottle, only if it is to be removed from the conveyor line. The bottle is held by the suction cup as it is transported by the starwheel for removal, through the use of a residual vacuum, while the remainder of the bottles continue down the conveyor line. In other words, a valve is opened to apply vacuum to a particular suction cup to hold the bottle to be removed and then the valve closed so that particular bottle is held by the residual suction present in the suction cup and the tubing and thus removed from the conveyor line.This type of system presents difficulties because there is not a continuous vacuum on the bottle that is being transported off the conveyor by the starwheel, and any leakage in the system can cause a line jam or lose the bottle that is being removed. Other types of prior art systems do provide for a positive vacuum on the bottle to be segregated, but use a separate valve for each bottle so as to apply the vacuum constantly during the segregation cycle by the starwheel. The use of a plurality of separate valves is relatively complicated and expensive and also provides for significant maintenance problems since all of these separate valves must be maintained in proper operating condition.

The present invention is defined in the appended claims, to which reference should now be made.

The invention will be described by way of example with reference to the drawings, in which: Figure 1 illustrates a front perspective view of inspection equipment including a vacuum starwheel embodying the present invention Figure 2 illustrates a rear perspective view of the inspection equipment of Figure 1; Figure 3 illustrates in schematic form the various functions which occur as the container is moved through various positions by the vacuum starwheel; Figure 4 illustrates the details of the porting in a stationary hub and in a rotating hub; Figure 5 illustrates a cross-sectional side view showing the stationary and rotating hubs; Figure 6 illustrates a porting arrangement for a single line output with two outputs; Figure 7 illustrates an altcmate arrangement for the elongated ports using a sequence of small holes; Figure 8 illustrates a multiple porting arrangement;; Figure 9 illustrates the proper relative size between the rotating and the stationary segregation of the bottles by the starwheel.

However, the mechanism eliminates the plurality of separate valves and has a very simple design using a stationary and rotating hub that contain commutating ports so arranged to provide a constant vacuum to each bottle in the starwheel unless it is to be segregated from the others on the conveyor line. If a particular bottle is to be segregated then the vacuum is removed, thus releasing that bottle from the starwheel at a particular position while all others remain in the starwheel and are released at some other position. The device provides for a very positive release of a bottle from the vacuum starwheel at a selected position during its rotation by interrupting the vacuum with a burst of pressure. The starwheel hub caq be designed to accept bottles from a single infeed and segregate them into two or more outfeed positions.Additionally, the apparatus can provide for a pressure purge of each port, pine and suction cup during every rotation of the starwheel so as to clear these parts of any debris.

Specifically, the mechanism is used as a vacuum sorting mechanism for transferring containers from at least one infeed position to any one of at least two independent outfeed positions and includes a rotary member including at least one rotating port and a corresponding radially extended vacuum directing and holding means that connects the rotating port to a container and with a stationary member interfaced with the rotary member. The stationary member includes at least four stationary ports arranged in sequence in the direction of rotation of the rotating port.The first stationary port hubs; Figure 10 illustrates the range over which the rotating port can receive a pressure pulse to release a container; Figure 11 illustrates a rotating port too large in size relative to the stationary ports; Figure 12 illustrates a rotating port too small in size relative to the stationary ports; and Figure 13 illustrates a multiple outfeed system using the porting shown in Figure 8.

The vacuum starwheel illustrated has positive control of containers, such as bottles, at all times during the transfer and is elongated in the direction of and coincident with the arc path of the rotating port and is connected to a vacuum source. The second stationary port is small in length compared to the elongate ports and is coincident with the arc path of the rotating port and is positioned proximate the first elongated port and with the second port connected to a valve that normally directs vacuum to the port but may be actuated to direct a vacuum eliminator or abating means to the port. The third stationary port is elongated in the direction of and is coincident with the arc path of the rotating port and is positioned proximate the second port and connected to a vacuum source.The fourth stationary port is small in length compared to the elongated port and is coincident with the arc path of the rotating port and is positioned proximate to the third port and is connected to a vacuum eliminator or abating means.

The size and position of the rotating and stationary ports are such that an uninterrupted flow of vacuum will be received by the rotating port as it rotates across the first three stationary ports, thus applying a positive vacuum to the container at all times as it is transferred from the beginning of the first port to the fourth port where it is released. In addition, the valve may be actuated, thus directing the vacuum eliminator means to the second port at the approximate time to release the container at the second port position.

Figures 1 and 2 show perspective views from the front and rear of a conveyor line passing by a bottle inspection station and including a vacuum starwheel embodying the present invention. The conveyor line includes an infeed conveyor line 10 having a conveyor belt 12 for conveying a plurality of containers, such as bottles 14. Rails 16 help to maintain the bottles in position during conveyance. The bottles 14 are guided by the rails 16 into a vacuum starwheel generally designated by reference numeral 18 and with the bottles 14 transferred off the conveyor line 10 by the vacuum starwheel 18 to pass by bottle inspection equipment 20.It is to be appreciated that although the vacuum starwheel guides the bottles to a bottle inspection position. and the acceptance and rejection of the bottle is in accordance with the particular form of the inspection made by the bottle inspection equipment 20, other arrangements are possible. For example, the vacuum starwheel may be used to segregate the bottles in accordance with size or shape, or the vacuum starwheel may be used to merely subdivide the bottles coming from an infeed conveyor line to a plurality of outfeed conveyor lines as shown in Figure 13. In addition, more than one infeed conveyor line may be used to feed the containers to the vacuum starwheel.

In the particular use of the mechanism as shown, the bottle inspection equipment 20 provides a determination of a particular type of inspection to produce a control signal to control the vacuum starwheel 18 to either deposit the bottle inspected to one of two outfeed conveyors designated as outfeed conveyors 22 and 24. Specifically, outfeed conveyor 22 may actually be a continuation of infeed connector 10 and with the conveyor belt 12 extending below the vacuum starwheel 18 to form the conveyor belt for the outfeed conveyor 22. The outfeed conveyor 24 may be a short conveyor using a conveyor belt 26 and may represent a conveyor belt for rejected bottles and with the bottles passing off the conveyor belt to a reject bin 30. The outfeed conveyors 22 and 24 also include railings 16 for guiding the bottles in the outfeed lines.

When the bottle inspection equipment 20 provides the proper inspection, the bottle inspection equipment 20 produces the control signals which are fed to valving located in a control console 32 to provide for the proper control of pressure and vacuum to the vacuum starwheel 18 to deposit the bottles in either of the outfeed conveyors 22 and 24 in accordance with the inspection.

The vacuum starwheel 18 includes an upper rotating member 50 having a plurality of recesses 52 to support the neck portions of the bottles 14. The member 50 rotates along with a rotating hub 54. Extending from the rotating hub 54 are a plurality of tube members 56 each including a suction cup 58 at i.ts end. The tubular members 56 transfer a vacuum or pressure from within the rotating hub 54 and from a source of vacuum or pressure within the console 32 to either hold the bottles 14 in engagement with the cups 58 or release the bottles from engagement with the cups.

The tubes 56 and cups 58 are supported on the rotating hub 54 above a rotating starwheel 60 having pockets 62 to receive the body portion of the bottles 14. It can be seen, therefore, that the pockets 62 in the starwheel 60, the tubes 56 and the cups 58 and the recesses 52 in the member 50 are all in radial alignment and all rotate together with the rotation of hub 54.

As shown in Figure 5 which illustrates the vacuum starwheel assembly 18 in crosssection, the rotating hub 54 is driven by a driveshaft 64 which driveshaft is rotated by a motor 66 supported by the console 32.

As shown in Figure 5, the rotating hub 54, the upper member 50, the tubes 56 and cups 58, the stanvheel 60 all rotate together relative to a stationary hub 68. The driveshaft 64 passes through the stationary hub 68 which acts as a support and bearing housing but the driveshaft 64 does not provide any rotation of the stationary hub 68.

The rotating hub 54 and stationary hub 68 are separated by a ring 74 of plastics, or suitable material, which operates as a bearing for the relative rotation between the two hub members and additionally provides for a sealing between the two members. This ring 74 is attached and sealed to the rotating hub 54.

Referring to both Figures 4 and 5, it can be seen that the rotating hub 54 includes a plurality of internal cylindrical channels 70 which connect the tubes 56 down to a like number of small ports 72 in the ring 74, thus for each vacuum path there is a suction cup 58, tube 56, internal cylindrical channel 70 and a separate associated port 72. The ports 72 are positioned at a constant radial distance and equally spaced with respect to the centre of the hub 54. This constitutes the porting arrangement of the rotating stanvheel assembly 18.

The stationary hub 68 has a porting arrangement on its top surface that establishes the segregating capabilities of the rotating starwheel assembly 18. A typical form of a recessed porting arrangement for the stationary hub 68 to accept a simple line input and separate it into two outputs is shown in Figure 4 and with an alternative arrangement shown in Figure 6. The recessed porting consists of a first, elongate port 80, a second, smaller port 96, a third elongate port 88, and a fourth, small port 106. These ports are all positioned at the same constant radial distance as the ports 72 in the rotating hub 54.A constant vacuum source 89, which may be located inside the console 32, is connected to elongated port 80 via opening 84, internal hub channel 82 and pipe 86. Pipe 102 and internal hub channel 98 supplies port 96 with either vacuum or pressure from a reject selector valve 100. Pipe 94, internal hub channel 92 and opening 90 supplies elongated port 88 with vacuum from the same source as port 80. Pipe 110, internal hub channel 108 supplies por 106 with pressure.

In the normal operating condition for this two channel segregator, valve 100 supplies vacuum to port 96. This constitutes the porting arrangement for the stationary hub 68.

As the rotating hub 54 rotates on top of the stationary hub 68, the ports 72 in the rotating hub 54 move sequentially over the ports 80, 96, 88 and 106 in the stationary hub 68. If any particular port 72 is traced in rotation as it moves across the fixed ports, a vacuum will be applied to the port 72 and its associated suction cup 58 as soon as its leading edge communicates witll the leading edge of elongated port 80. This vacuum will continue to be applied until the trailing edge of the port 72 loses communication with the trailing edge of te port 80. Just prior to this position, however, the leading edge of the port 72 has communicated with the leading edge of port 96 which is a vacuum source, thus vacuum is never lost at the suction cup 58.Figure 9 shows the required size and spacing dimensions between the elongated port 80 and the small port 96 as they rclate to the rotating port 72. Rotating port 72 must slightly overlap (shaded area) both stationary ports 80 and 96 during the transition between them in order to maintain a constant vacuum supply to its associated suction cup. These same conditions are required of all other stationary port spacings. Vacuum will continue to be supplied to the port 72 until its trailing edge loses communication with the trailing edge of port 96, however, in this position the leading edge of the port 72 has communicated with the leading edge of the elongated port 88. Since port 88 is a source of vacuum. the port 72 will continue to receive vacuum until its trailing edge loses communication with the trailing edge of port 88.In this position, the leading edge of the port 72 communicates with the leading edge of the port 106 but, since port 1G6 is a pressure source, then port 72 directs this pressure into the internal channel 70, pipe 56 and suction cup 58, thus eliminating the vacuum from that cup. If a bottle was picked up by the suction cup 58 at the leading edge of port 80, it would be firmly held by a positive vacuum until it reached the leading edge of port 106 where it would be released.

lf desired, the bottle could be released at port 96 by applying a pressure pulse from valve 100 at the appropriate time when the port 72 was over port 96. Figure 10 shows the range D, where rotating port 72 can receive the pressure pulse without disturbing the rotating ports on either side.

This arrangement allows an adequate time to eliminate the vacuum from the internal channel 70, pipe 56 and suction cup 58.

Tt also rcsults in a sufficient distance (x) between rotating port 72 and stationary ports 80 and 88 to insure a good seal. By the application of a pressure pulse at the appropriate time a bottle may be removed from the starwheel at port position 96 or, if no pressure pulse is applied, then the bottle will be removed at port position 106.

The length of the elongated port essentially determines the distance the container is transported from the time it is picked up by the suction cup to the release point at the pressure reject port 96. The size of the small pressure 96 port does not alter the total transport distance appreciably since it is very small in size compared to the length of the elongated port. In practice, the minimum length of the elongated port is determined by the container diameter being handled. The elongated port must be of sufficient length to allow container clearance on the multiple output. Proper port size is necessary to accomplish a proper and reliable rejection sequence. Figure 11 shows the rotating port 72 too large relative to the spacing between stationary ports 80 and 96 (of 96 and 88).This arrangement allows the pressure pulse from stationary port 96 to be directed into the vacuum port 80 and vice versa, which upsets the balance in the system causing malfunctions. Figure 12 illustrates the difficulty encountered if the rotating port 72 is too small in size compared to the distance between the stationary ports 80 and 96 (or 96 and 88). In the position shown, rotating port 72 will receive no vacuum from any stationary port and, thus, could not apply the required constant vacuum to its associated suction cup.

It is obvious that more than two reject points can be used by adding additional ports and associated valves in the stationary hub 68. A porting configuration that segregates containers into four groups is shown in Figure 8. This is the type of porting used with the system of Figure 13.

Figure 7 shows an alternate method of constructing the elongated ports by using a closely spaced sequence of small holes connected below by a common vacuum chamber and it is to be appreciated that when the term " elongated port " is used, it includes an arrangement as shown in Figure 7 or other similar arrangements.

The porting system as shown will operate if the ports 96 and 106 are directed to atmosphere instead of a pressure source such as an air comDressor. The valve 100 may be an electric solenoid actuated air valve that directs the flow into the port.

The release response time is slower if the ports are directed to atmosphere instead of a pressure source since it takes longer to eliminate the vacuum from the tubes and internal channels. For highspeed production lines the pressure pulse is the most desirable.

As the rotating hub 54 continues rotating, successive ones of the ports 72 will pass over an additional port 112 which is connected through an internal cylindrical channel 114 to the source of pressure 104.

The pressure provides for purging successive ones of the ports 72, the internal cylindrical channels 70, the tubes 56 and the suction cups 58 of any extraneous matter which could clog these members.

Turning now to Figure 3, a functional diagram shows the operation of the vacuum starwheel at a number of radial positions designated A through E. These radial positions correspond to the same radial positions shown in Figure 4. As each bottle moves along the infeed conveyor 10, each bottle 14 engages a cup 58 at the end of a tube 56 and at position A vacuum is applied to hold the bottle against the cup and in the starwheel pocket so as to transport it off the conveyor for inspection. The bottle is passed through the inspection point B shown in Figure 3 and is securely maintained in position since a positive vacuum is applied to the bottle throughout the transfer of the bottle.

If the bottle was faulty, the valve 100 shown in Figure 4 is controlled to supply a pressure pulse at the appropriate time to the port 96 which is located at position C, and the bottle is positively released to the outfeed conveyor 25 to send the bottle to the reject bin 30 as shown in Figure 1. If the bottle was good, then vacuum is maintained at position C which corresponds to the posi tion of the port 96 and the bottle is transferred through position C and on to position D. The positive vacuum is applied at all times through the use of vacuum applied to the elongated ports 80 and 88 and to the port 96, all as shown in Figure 4. At position D, the tube 56 and the cup 58 receive pressure from port 106 and the bottle is released to outfeed conveyor 22.

As the rotating hub progresses, each particular port 72 is moved to position D where air pressure is supplied to purge the channels, tubes and cups to clean them of any debris.

It can be seen, therefore, that the vacuum starwhel provides for a positive vacuum to hold objects, such as bottles, to maintain the bottles in position during transfer by the starw'neel, and with the use of a pair of hub members, one rotating relative to the other, and with a first hub member including a plurality of ports corresponding to and connecting with tubes and cups to retain the bottles and with the second hub including a plurality of ports connected to either vacuum, pressure or atmosphere. At least the first and third of the ports in the second hub are elongate, and a second, small port is disposed intermediate the two elongate ports. A fourth, small port is located after the two elongate ports.

Vacuum is always applied to the two elongate ports, and either vacuum or pressure applied to the second port to either release a bottle at the intermediate position or to transfer the bottle along the entire length of the two elongate ports and then release the bottle.

As will be seen from the above description taken with the drawings, the shapes and location of the ports are such that, as they move between a position in which it is in communication with the first port 80 in the second member to a position in which it is in communication with the third port 88 in the second member, the ports 72 in the first member are always each in communication with at least one of the three ports 80, 96, 88 in the second member but never more than two of these three ports.

Furthermore, when one of the ports 72 is in communication with two of these three ports, it is only in partial communication with each of these two ports.

Although the application has been disclosed with reference to a particular embodiment, such as with bottle inspection equipment, it is to be appreciated that the invention is caDable of various adaptations and modifications and the invention is only to be limited by the appended claims.

WHAT WE CLAIM IS: 1. A transfer mechanism for transferring objects from one infeed position selectively to one of at least two outfeed positions, the mechanism comprising: a first member having at least one means for retaining one of the objects when a vacuum is applied to an associated port in the member; a second member including at least three ports; the first member being continuously movable relative to the second member such that the ports in the second member are disposed in the path of movement of the port in the first member for movement of the port in the first member into sequential communication with the ports in the second member; vacuum means for continuously applying a vacuum to the first and third ports in the second member; ; control means for selectively applying either a vacuum or at least atmospheric pressure to the second port in the second member; the shapes and location of the ports being such that as it moves between a position in which it is in communication with the first port in the second member to a position in which it is in communication with the third port in the second member, the port in the first member is always in communication with at least one of the three ports in the second member, but never more than two of the tree ports in the second member, and, when in communication with two of

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Claims

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channel 114 to the source of pressure 104.

The pressure provides for purging successive ones of the ports 72, the internal cylindrical channels 70, the tubes 56 and the suction cups 58 of any extraneous matter which could clog these members.

Turning now to Figure 3, a functional diagram shows the operation of the vacuum starwheel at a number of radial positions designated A through E. These radial positions correspond to the same radial positions shown in Figure 4. As each bottle moves along the infeed conveyor 10, each bottle

14 engages a cup 58 at the end of a tube 56 and at position A vacuum is applied to hold the bottle against the cup and in the starwheel pocket so as to transport it off the conveyor for inspection. The bottle is passed through the inspection point B shown in Figure 3 and is securely maintained in position since a positive vacuum is applied to the bottle throughout the transfer of the bottle.

If the bottle was faulty, the valve 100 shown in Figure 4 is controlled to supply a pressure pulse at the appropriate time to the port 96 which is located at position C, and the bottle is positively released to the outfeed conveyor 25 to send the bottle to the reject bin 30 as shown in Figure 1. If the bottle was good, then vacuum is maintained at position C which corresponds to the posi tion of the port 96 and the bottle is transferred through position C and on to position D. The positive vacuum is applied at all times through the use of vacuum applied to the elongated ports 80 and 88 and to the port 96, all as shown in Figure 4. At position D, the tube 56 and the cup 58 receive pressure from port 106 and the bottle is released to outfeed conveyor 22.

As the rotating hub progresses, each particular port 72 is moved to position D where air pressure is supplied to purge the channels, tubes and cups to clean them of any debris.

It can be seen, therefore, that the vacuum starwhel provides for a positive vacuum to hold objects, such as bottles, to maintain the bottles in position during transfer by the starw'neel, and with the use of a pair of hub members, one rotating relative to the other, and with a first hub member including a plurality of ports corresponding to and connecting with tubes and cups to retain the bottles and with the second hub including a plurality of ports connected to either vacuum, pressure or atmosphere. At least the first and third of the ports in the second hub are elongate, and a second, small port is disposed intermediate the two elongate ports. A fourth, small port is located after the two elongate ports.

Vacuum is always applied to the two elongate ports, and either vacuum or pressure applied to the second port to either release a bottle at the intermediate position or to transfer the bottle along the entire length of the two elongate ports and then release the bottle.

As will be seen from the above description taken with the drawings, the shapes and location of the ports are such that, as they move between a position in which it is in communication with the first port 80 in the second member to a position in which it is in communication with the third port 88 in the second member, the ports 72 in the first member are always each in communication with at least one of the three ports 80, 96, 88 in the second member but never more than two of these three ports.

Furthermore, when one of the ports 72 is in communication with two of these three ports, it is only in partial communication with each of these two ports.

Although the application has been disclosed with reference to a particular embodiment, such as with bottle inspection equipment, it is to be appreciated that the invention is caDable of various adaptations and modifications and the invention is only to be limited by the appended claims.

WHAT WE CLAIM IS: 1. A transfer mechanism for transferring objects from one infeed position selectively to one of at least two outfeed positions, the mechanism comprising: a first member having at least one means for retaining one of the objects when a vacuum is applied to an associated port in the member; a second member including at least three ports; the first member being continuously movable relative to the second member such that the ports in the second member are disposed in the path of movement of the port in the first member for movement of the port in the first member into sequential communication with the ports in the second member; vacuum means for continuously applying a vacuum to the first and third ports in the second member;; control means for selectively applying either a vacuum or at least atmospheric pressure to the second port in the second member; the shapes and location of the ports being such that as it moves between a position in which it is in communication with the first port in the second member to a position in which it is in communication with the third port in the second member, the port in the first member is always in communication with at least one of the three ports in the second member, but never more than two of the tree ports in the second member, and, when in communication with two of

the three ports in the second member, is only in partial communication with each of these two ports.
2. A transfer mechanism according to claim 1, including a fourth port in the second member, and means for continuously applying pressure to the fourth port.
3. A transfer mechanism according claim 1 or 2, including a further port in the second member, and means for applying pressure to the said further port to purge the mechanism when the port on the first member communicates with the further port on the second member.
4. A transfer mechanism according to claim 1, 2 or 3, in which the first member is a rotatable hub comprising a starwheel having a plurality of pockets ar und its periphery in which the objects can be held.
5. A transfer mechanism according to claim 3, in which the port(s) in the first member and the ports in the second member are disposed in respective contiguous substantially palanar surfaces.
6. A transfer mechanism according to claim 4, including lubricating bearing means between the first and second members to provide a seal therebetween.
7. A transfer mechanism according to any preceding claim, in which either or both of the first and third ports in the second member is at least partially formed from a plurality of closely-spaced small ports.
8. A transfer mechanism according to any preceding claim, in which the control means comprises valve means connected to the vacuum means and to a pressure source for selectively applying a vacuum or pressure to the second port in the second member.
9. A transfer mechanism according to any preceding claim, including means for testing the individual objects when the or a port in the first member is disposed at an intermediate position along the length of the first port in the second member and commanding the control means in response to the result of the test.
10. A transfer mechanism substantially as herein described with reference to the drawings.