Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B67—OPENING, CLOSING OR CLEANING BOTTLES, JARS OR SIMILAR CONTAINERS; LIQUID HANDLING
  • B67B—APPLYING CLOSURE MEMBERS TO BOTTLES JARS, OR SIMILAR CONTAINERS; OPENING CLOSED CONTAINERS
  • B67B3/00—Closing bottles, jars or similar containers by applying caps
  • B67B3/22—Closing bottles, jars or similar containers by applying caps by applying snap-on caps

Definitions

• This invention relates to a capping apparatus and method of capping.
• it relates to an apparatus for applying press-on, twist off (PT) caps to containers such as glass jars.
• PT press-on, twist off
• capping apparatus is fitted above and at an angle to a horizontal conveyor, along which containers pass during the capping process.
• capping apparatus Such a capping apparatus, or capper, is known in which caps pass down a chute to a cap pick-up point at which they are collected one-by-one by containers passing beneath che end of the chute. At the cap pick-up point, the leading cap is engaged by stops just ahead of its transverse diameter which prevent the cap from falling out of the chute. A hold-down device presses on the top of the cap to ensure that the cap cannot inadvertently twist over the stops and then out of the chute. This is aggravated by further caps behind the leading cap which push on the leading cap and may cause a cascade of caps onto the jars on the conveyor below. Capping processes are high speed operations, generally applying caps at a rate of 400 to 500 caps/min.
• Ic is therefore critical that no cascade of caps occurs since the capping process would have to be halted in order to clear the caps from the bottle conveyor. Conversely, retention forces applied to the cap firstly by the chute and then by the hold down and stops must not be so great that caps are not released and bottles missed in the capping process. Careful control of chute dimensions is therefore of paramount importance in conventional equipment.
• the sides of the chute are moved to a width ju ⁇ greater than the cap width and a plate or block above the chute is lowered to limit the head ⁇ oace above caps in the chute.
• the sides and top plate of the chute are set to a minimum clearance for clear passage of the caps. This prevents lateral movement or undue twisting of the caps in the chute but the dimensions must not be reduced to such an extent that the caps stick within the chute itself.
• the hold down is spring loaded so that as a jar approaches the leading cap, it lifts the cap over the stops against the biasing action of the hold down. At this point the cap is at about 26° to the top of the jar.
• a slide block and so-called “duckbill” assembly which are also spring-loaded, bias the cap towards the jar, preventing the cap from rising up away from the jar.
• the duckbill of the prior art is a two-piece assembly, each piece being individually sprung. The first part is disposed parallel to the plane of the chute and extends around the hold down and slide block behind it.
• the second part of the duckbill is at an oblique angle to the firsc part and is disposed more or less horizontally and parallel to the plane of the top of the jars. It can therefore be seen that the cap has to pass from a position in which it is at an angle to the jar top to a final horizontal position in which it sits squarely on the jar.
• caps for applying to glass jars include a plastisol compound. Prior to capping, the caps are pre-heated with steam to about 105°C so that the compound becomes pliable. At the cap pick-up point, glass thread on the jar engages with the pliable compound and forms an impression in the compound, making the cap difficult to move. It is therefore important that the cap be applied level in the first instance.
• cappers tend not to translate fully to the position in which they sit squarely, forming a secure package.
• compound within a PT cap on a glass jar is heated to about 120°C and can therefore flow freely so that the cap can move and adjust itself to seat squarely as the compound slowly forms itself about the glass thread and sealing surface.
• little or no extra heat is used, so that little or no flow of the compound arises and any cap which is not already seated squarely remains tilted and therefore both insecure and unsightly.
• pressure is applied to a tilted PT cap at low temperatures, tearing of the compound may arise since it is not free to flow.
• a machine for capping a container comprising: a chute having an outlet; one or more stops for preventing a cap from falling out of the chute outlet; means for holding the cap on the chute at the chute outlet; and means for biasing the cap downwardly towards the container; in which the capping machine further comprises means for attracting the leading edge of the cap upwardly away from the container as the biasing means biases the trailing edge of the cap downwardly towards the container.
• the attraction means comprises one or more magnets. There may be two sets of one or more magnets, poles of the two sets being at an oblique angle to each other.
• the attraction means are located in a slide member, which may comprise first and second portions, at an oblique angle to each other.
• the attraction means may comprse a pair of magnets at a first angle to the chute and a third magnet at a second angle to the chute, the third magnet being substantially horizontal.
• the attraction means may comprise a pneumatic suction device, for example. Whilst other attraction means may be used, it is preferred that these be disposed that so as to prevent the cap from diving and to guide the cap to a level position where it can sit squarely on the container.
• the biasing means comprises a bar. This bar may extend across the whole width of a cap so as to prevent the cap from twisting laterally on a container. The bar may also extend upwardly, away from the cap so that there is room for the holding means, or hold down. The hold down may then also be wide since it has space to extend across the width of the cap and thus prevent twisting of the cap within the chute.
• the hold-down preferably comprises a bevelled surface which enables caps to move fast and freely along the chute to the outlet.
• the hold down may also include a convex surface which guides the cap towards its desired horizontal position. The hold down preferably does not contact the cap prior to pick up of the cap by a container.
• a method of capping a container comprising the steps of: passing a cap along a chute to a chute outlet; retaining the cap at the chute outlet prior to pick-up of the cap by the container; and, subsequent to pick-up, biasing the trailing edge of the - 3 -
• Figure 1 is a side view of part of a prior art capping apparatus
• Figure 2 is a side view of part of the capping apparatus of the present invention
• Figure 3 is a side view of a hold down of the apparatus of figure 2;
• Figure 4 is an underside view of a slide block of the apparatus of figure 2.
• Figure 5 is a side view of the slide block of figure 4.
• Figure 1 shows a known capping apparatus comprising a chute 10 at 40° to the horizontal, along which caps will pass to a pick-up point 20.
• a chute 10 At the pick-up point 20, two stops (not shown) are provided, one either side of the chute outlet in order to hold the leading cap in position.
• a hold-down 30 having a small clearance from the chute at the pick-up point is provided to hold the leading cap on the chute as the cap sits against the stops.
• the capper comprises a slide block 40 and a two-part "duckbill" assembly 50, 60, so called because of its shape.
• the hold-down 30, slide block 40 and duckbill assembly 50, 60 (shown at rest in figure 1) are all spring loaded so that these components press down on a cap and are free to be deflected individually by the cap as it moves along the capping apparatus.
• a container such as a bottle or jar passes along a horizontal conveyor under the capper in the direction shown by the arrow in figure 1. As the leading edge of the jar impinges on a cap held at the pick-up point 20, it lifts the cap over the stops, against the force of the hold-down 30. Once the cap has exited the chute 10, it relies on the forward motion of the jar, together with downward pressure exerted in turn by the slide block 40 and duckbill 50, 60, to guide it into position on the jar.
• each component will spring back into its rest position prior to the passage of the next cap. Since the components are long, this results in a large movement in the form of deflection and springing back as each cap passes in turn. It can therefore be seen that each component will suffer a large degree of fatigue, particularly of their springs due to this continuous large movement. It will be apparent from figure 1 that in order to locate the cap on the jar, it is necessary for the cap to rotate from a first position approximately parallel to duckbill member 50 to a horizontal position parallel to the conveyor. This does not always occur, particularly in cases where the cap is 40mm in diameter.
• the hold down 30 does not extend across the width of the cap and is U-shaped in transverse section, so that it only contacts the cap at two points which are approximately 10mm apart, fairly centrally on the cap.
• the slide block 40 acts only on a central 10mm portion of the cap. This allows the cap freedom to twist over the stops if forced forward by impetus of caps behind it in the chute.
• Figure 2 shows a preferred capping apparatus of the present invention, having a hold down 130 which extends 5 across the width of a chute 110 and is bevelled from rear to front so that a cap is guided towards the chute outlet freely and easily and prevented from twisting within the chute 110.
• a bridge bar 140 having a cross-sectional diameter of approximately 5mm and extending over about 10 60mm across the apparatus and then perpendicularly upwards is provided beyond the pick-up point. The use of this bridge bar 140 thus provides space for a full-width hold-down 130.
• a one-piece contoured slide block 150 extends beyond 5 the bridge bar.
• the slide block has a first surface 152 at an acute angle to the horizontal and a second surface 154 which is substantially horizontal and parallel to the top of jars which pass along in the direction indicated by the arrow.
• the hold down 130, bridge bar 140 and slide block 150 are all spring loaded.
• a comparison of the apparatus of figure 2 with the apparatus of figure 1 clearly shows that the use of a bridge bar has enabled the overall length of the apparatus of figure 2 to be reduced considerably in 5 comparison with that of figure 1, thus reducing the deflection of individual components and the resultant fatigue. Furthermore, the distance travelled by the capped jars can be reduced by moving the sealing belt nearer to the capper. 0
• a side view of the hold down 130 is shown in figure 3.
• the hold down comprises a first surface 132 which is bevelled at an acute angle of approximately 16 degrees and a second curved surface 134.
• Figures 4 and 5 show underneath and side views respectively of the slide block 150.
• a pair of magnets 160 positioned symmetrically about the longitudinal axis, parallel to the lower surface 5 152 and set back 2mm from that surface, and a single third magnet 165 positioned centrally, parallel to the second lower surface 154 and set back 1mm from that surface. It can be seen that the magnet 165 is also set back from the front of the slide block so that it overlies the junction between surfaces 152 and 154.
• caps pass along the chute 110 to stops (not shown) at the chute outlet and pick-up point 120.
• the hold down 130 will not normally contact the leading cap until it is raised over the stops by the action of a bottle or jar passing under the capper as indicated by the arrow in figure 2.
• the bevelled surface of the hold down (figure 3) both prevents twisting of caps within the chute and acts as a guide towards the pick-up point 120.
• the fact that the hold down is full width also removes the need for the chute width to be adjusted to within a close tolerance of the cap width to prevent caps from cascading out of the chute onto the jars.
• plate or block 115 (figure 2) above the chute need not be lowered close to the caps for the same reason.
• the use of a wide hold down avoids time-consuming adjustment of the chute 110 and plate 115 to within a critical tolerance. It will also accommodate distorted caps which could normally jam in the chute.
• the cap is carried in the direction of the arrow by the movement of the jar and so passes to a point at which the bridge bar alone is pressing on the cap. At this point, the bridge bar 140 is acting on the rear half of the cap only and the magnets 160 attract the leading edge of the cap towards the slide block, thus rotating the cap towards the horizontal.
• the bridge bar 10 pushes down the trailing edge of the cap and the third magnet 165 pulls the front edge around the contour in slide block 150 to a horizontal position where it will sit squarely on the jar.
• the slide block 150 will not be contacted by the cap but it is possible that due to manufacturing tolerances of compound thickness, glass thread diameters and jar height, some caps will sit higher relative to the conveyor and will contact the block.
• the positioning of the third magnet 165 pulls the leading edge of the cap around the contour between surfaces 152 and 154 in the same way as in non-contacting caps, and the slide block 150 then presses down on the cap due to being spring-loaded.

Landscapes

• Mechanical Engineering (AREA)
• Engineering & Computer Science (AREA)
• Sealing Of Jars (AREA)
• Closing Of Containers (AREA)
• Telephone Function (AREA)
• Formation And Processing Of Food Products (AREA)
• Holding Or Fastening Of Disk On Rotational Shaft (AREA)
• Motor Or Generator Frames (AREA)
• Glass Compositions (AREA)
• Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)
• Centrifugal Separators (AREA)
• Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
• Details Of Connecting Devices For Male And Female Coupling (AREA)
• Seal Device For Vehicle (AREA)
• Medical Preparation Storing Or Oral Administration Devices (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10730397

Family Applications (1)

Country Status (10)

Cited By (2)

Citations (5)

• 1993
  • 1993-02-13 GB GB939302909A patent/GB9302909D0/en active Pending
• 1994
  • 1994-02-08 SG SG1996002915A patent/SG47576A1/en unknown
  • 1994-02-08 EP EP94905808A patent/EP0682638B1/de not_active Expired - Lifetime
  • 1994-02-08 WO PCT/GB1994/000235 patent/WO1994018108A1/en not_active Ceased
  • 1994-02-08 DK DK94905808.5T patent/DK0682638T3/da active
  • 1994-02-08 AT AT94905808T patent/ATE142982T1/de not_active IP Right Cessation
  • 1994-02-08 DE DE69400577T patent/DE69400577T2/de not_active Expired - Lifetime
  • 1994-02-08 ES ES94905808T patent/ES2092400T3/es not_active Expired - Lifetime
• 1995
  • 1995-08-11 FI FI953824A patent/FI120622B/fi not_active IP Right Cessation
  • 1995-08-11 NO NO953166A patent/NO303490B1/no not_active IP Right Cessation

Patent Citations (5)

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