GB2173777A - Cup dispenser - Google Patents

Abstract

A cup dispenser particularly for dispensing foam cups singly from a stack of cups which will normally be a vertical stack comprising a plurality of cam bodies (28) each having a cam surface (32) being a helix about the axis (31) of the body, each body carrying a helically extending projection or bead (33) about the body, the undersurface (32B) of the projection or bead presents an extension of the cam face (32A) to provide an enlarged cam face for providing a greater cup rim engaging cam surface than presented by the body itself. The bead dimensions are chosen for easy moulding. An improved cam profile has interengaging surfaces between the support ledge (50) and the upper side wall of the cup and an increased separation of the ledge (50) and dispensing cam surface (32A). <IMAGE>

Description

SPECIFICATION Cup dispenser This invention relates to a cup dispenser particularly for dispensing foam cups singly from a stack of cups which will normally be a vertical stack.

Because of the constraints of space in a dispenser used for dispensing cups, the dimensions of the components making up the dispenser must be minimized both as to size and number. Additionally, the movements of the components must be minimized.

One such dispenser comprises a plurality of cams spaced about a first axis (coaxial with the axis of the stack of cups) and drive means for rotating the cams together, each about an associated axis parallel to the first axis. A connector, for example a gear carrying a handle, connects the cams to the drive means for rotating the cams.

Each of the cams has a cam face which cam face is a helix about its axis and is arranged to engage the rim of the end cup of a stack of cups located in the dispenser so that rotation of the handle through an angle of about 30 degrees, rotates the cams in one direction pushing the end cup away from the remainder of the stack, dispensing the cup. The handle is then returned through the same arc to its initial position readying the cam for dispensing the next cup.

Where use of such a dispenser has been tried to dispense foam cups, the dispenser of a construction as used to dispense conventional paper or thermoplastic cups is not satisfactory. Particularly, the rotation of the handle through the small arc (about 30 degrees) must be sufficient to cause the foam cup to be dispensed. Therefore, the helical angle of the cam face of the cam (which cam face is a helix about the cam's axis) must be such as to eject the engaged foam cup. If the helical angle of the dispensing cam face is too steep, the foam cup will be crushed. If the helical angle is too shallow, the resultant structure of the cam would be too large for the dispenser size required.

Conventionally, the dispensing cam face is downwardly facing, and in the direction of any di ameter, is normal to the axis of rotation of the cam. This disposition of the cam face however, is not satisfactory for use in disperising foam cups.

Particularly, this cam face does not provide a satisfactory dispensing action, tending to dig into the rim of the cup and scoring the rim, by a point contact between the cup rim and cam face when the cam face engages the rim, seriously damaging the cup.

In our British Patent Number 2081238 a dispenser for dispensing foam cups one by one from a stack of cups was taught which provided improved dispensing. This dispenser comprised a plurality of cams spaced about a first axis, coaxial with the axis of the stack of cups when present, and drive means for rotating the cams together, each about an associated axis parallel to the first axis.Each of the cams has a cam face which is a helix about its axis and is arranged to engage the rim of the end of a stack of cups located in the dispenser so that rotation of the cams in one direction pushes the end cup away from the remainder of the stack to dispense it, the spiral angle of the helix being in the range of about 8 to 14 degrees, and in which the cam face of each cam is chamfered with respect to any diameter of the cam with the angle of the chamfer through its entire length being in the range of substantially 22 degrees to substantially 28 degrees. This achieves a more satisfactory dispenser overcoming some of the problems of the prior art. While the above structure is an improvement to prior art structures, nevertheless, dispensing is not fool proof in all instances particularly where the cups are held together by substantial forces (electrostatic for example).In those instances where the cam face is applied to the rim of the cup, the force may not be sufficient to separate the cups by the rotation of each of the rotating cam faces. In another instance where the cups to be dispensed are of lower density or lesser rigidity, the cup rim because of its lower density or lesser rigidity is deformed by the pressure of the cam and thereafter the cam rides over the deformed rim of the cup without discharging the cup.

In addition damage can be caused by compressing the rim at the start of the dispensing process or by shock loads at the end of a dispensing operation.

It is therefore an object of this invention to provide a cam profile which provides a more satisfactory dispensing action to discharge the lowermost cup without damaging the rim. According to one aspect the invention provides a cup dispenser for dispensing foam cups one by one from a stack of cups, the dispenser comprising a plurality of injection moulded cam bodies of plastics material spaced about a first axis, co-axial with the axis of the stack of cups when present, each body comprising an outer wall of predetermined thickness having a longitudinally extending axis parallel to the first axis, the body carrying a cam surface about the longitudinal axis of the body, drive means for rotating the cam bodies and thus the cam surfaces together, each of the cam surfaces being a cam face which is a helix about the axis of the body and arranged to engage the rim of the lowest or bottom cup of a stack of cups located in the dispenser so that rotation of the cam bodies in one direction pushes the lowest cup away from the remainder of the stack to dispense it; the spiral angle of the helix preferably being in the range of about 8 degrees to about 14 degrees and the cam face of each cam body preferably being chamfered throughout its entire length with respect to any diameter of the cam body at an angle of substantially 22 degrees to substantially 28 degrees, characterized in that each body carries a helically extending projection or bead about the body, the undersurface of the projection or bead presenting an extension of the cam face of each body to provide an enlarged cam face for providing a greater cup rim engaging surface than presented by the body itself, (i) the distance the projection extends from the wall of the cam body, (ii) the thickness between the top of the bead or projection and extension of the cam face from the wall of the cam body, and (iii) the thickness of the said wall of the body being such that on formation of the body by injection moulding there is uniform cooling of the parts so that there is no distortion of the part when removed from the mould.

With this construction, the cam bodies carrying the helical projections can be effectively manufactured by injection moulded processes to provide a reliable structure.

In a preferred embodiment, where the cam body has a diameter of 26 mm., and wall thickness in the range of 2.5 to 3.5 mm, preferably substantially 3 mm., the distance the projection extends from the cam body is in the range of about .5 to 1.5 mm., preferably substantially 1 mm., and the average distance between the top of the projection and the point where the cam surface starts to be carried by the projection is substantially 2-3 mm.

Each cam has an upwardly facing cam surface for engaging the next cup in the stack and holding up the stack as the end cup is dispensed and each cam has a ledge for supporting the lowermost cup and thus the stack between dispensing operations.

There is a moment at the end of the return rotation stroke of the cam when the stack of filled ingredient cups is allowed to fall from the upwardly facing cam surfaces onto the ledges. A typical stack of 40 cups weighs up to 80 grammes and this weight falls about one and a quarter centimetres upon the six ledges and shock loads the rims causing damage.

According to another feature of the invention, which feature may be claimed independently, the ledge and upper side wall of the cups are shaped and dimensioned such that when the stack falls at the end of a dispensing operation from a position supported by the upwardly facing cam surfaces to a position supported by the ledges, the initial contact between each ledge and the cup is between sloping parts of the upper cup wall and sloping (straight or curved) parts of the front edge of the ledge.

This serves firstly to centre the cups between the cams and equalise the forces around the cup thus reducing rim damage and secondly by contacting the side wall of the lowermost cup, the drop of the containers is slowed, the deceleration reduced and the subsequent shock load reduced very considerably, so much that it might take the weight of the loaded ingredient cups to finally settle the stack to rest upon the top surfaces of the ledges. Preferably the upper side wall of each cup is formed with an under chamfer below the rim and the front edge of each ledge is formed with a corresponding chamfer for example 40 to 60 degrees to the horizontal, preferably about 50 degrees to the horizontal.

In the dispenser of U.K. Patent Specification 2081238 the distance between the upper surface of the ledge of each cam and the first part of the cam surfaces to contact the upper rim surface of the flowermost cup was approximately the same as the height of the cup rim. On occasions this causes the rim to be crushed between these surfaces as the cams rotate before the lowermost cup clears the ledge.

In another feature of the invention, which feature may be claimed independently, this distance is increased to ensure that the lowermost cup is clear of the ledges before being contacted by the cam surfaces. The gap has been increased so that when the cam surface enters the space between the lowermost rim and the rim immediately above there is a space of at least 0.5 mm between the rim and cam surface so that further cam rotation is needed before the cam surface contacts the rim.

A cup dispenser according to an embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure l is a perspective view of a foam cup dispenser, Figure 2 is a top plan view of the dispenser shown in Figure 1, Figure 3 is a perspective view of a cam body incorporated in the dispenser of Figures 1 and 2, Figures 4 and 5 are side cross-sectional views through the dispenser illustrating the positions of cam bodies in the process of discharging the lowermost cup from a stack of cups, Figure 6 is a close-up side view of part of a cam body shown in Figures 4 and 5 illustrating its engagement with the rim of the cup, and Figures 7a and 7b are views, on an enlarged scale, of a known cam profile and an improved cam profile at the point where the cam surface enters the space above the lowermost cup and rim.

With reference to Figures 1 and 2, there is shown a cup dispenser 10 having a hollow casing 12 having upper and lower halves 14 and 16 respectively, connected together by three equi-angularly spaced bolts 18 through bolt housings one of which is shown at 20. Dispenser 10 has a vertical axis 22 therethrough with its top 24 open to define a bore 26 for holding a stack of cups 27 (only two of which are shown). Six injection moulded cam bodies 28 of plastics material are spaced circumferentially about axis 22 in casing 12 for the ejection of foam cups, one at a time from the stack 27 of foam cups 30.Each cam body 28 has a longitudinally extending axis 31 (see Figure 3) parallel to axis 20 and carries a helically extending downwardly facing cup dispenser cam surface 32 about cam body 28. Each-cam body 28 is angularly oscillatable about axis 31 by drive means in the form of a common ring gear 34 (see Figures 1 and 2). Ring gear 31 is formed on its inner periphery with teeth 36 which engage a pinion gear 38 on each of the cam bodies 28. Ring gear 34 has operating handle 40 which projects through aperture 42 in casing 12 and by means of which the ring gear 34 can be reciprocated through an angle of about 30 degrees as indicated by arrow 44. Each cam body 28 has curved upright surfaces 46 forming in cross-section part of an arc of a circle, generally flat upright surface 48 (see Figure 3) and support ledge 50 extending radially from flat surface 48. In use the ledge 50 projects into bore 26 of the dispenser for carrying the stack of foam cups by engaging under the rim 51 of the lowermost cup to hold up the stack of cups (not shown).

Each cam body 28 also comprises an upwardly facing cam surface 52 located above surface 46 but not above surface 48. These surfaces are both chamfered on an angle to any diameter of the cam, the lower cam surface 32 being at an angle of 25 degrees with respect to such diameter and the upper facing surface 52 being at an angle of 22.5 degrees with respect to such diameter. Cam surface 32 comprises two portions 32A and 32B (see Figure 6) one being a continuation of the plane of the other. Cam surface 32B protrudes about 1 mm.

from surface 46 and is carried by helical bead or projection 33 (see Figures 5 and 6) extending about 1 mm. from surface 46 extending from a position proximate the ends 50A and 50B of ledge 50 helically around surface 46 from position 46A (where surface 46 meets surface 48 at one side) to position 46B (where surface 46 meets the other side of surface 48) proximate ledge 50. Projection or bead 33 is about 2.5 mm thick (about the same thickness as the wall of cam body 28 carrying surfaces 46 and 48 which is about 3 mm.), and extends substantially 300 degrees along surface 46. Each cam body 28 is injection moulded of plastics material.

Because the thicknesses and other dimensions of the individual parts making up the cam body 28 (for example the support pins 60 at either end, the projection or bead 33, the thickness of the wall carrying surfaces 46 and 48, etc.) are substantially uniform without substantial variations, manufacture is relatively simple without the incurring of special moulding costs for special mould designs and cooling of the injection moulded part while achieving a high quality part.

In operation of the dispenser shown in Figures 4 and 5, the lowermost cup seats on ledge 50. As handle 40 is rotated in opening 42 from one side to the other, each cam surface 32 of each body is brought to bear on the upper rim of the lower foam cup, pushing the cup downwardly while the second cup (and thus the rest of the stack of cups) is supported by the upper surface 52 until the lower cup has been pushed away. After the lower cup has fallen and after handle 40 is returned to its initial position, the second cup and thus the rest of the stack of cups becomes vertically aligned with surface 48 on each body 28 and falls about one and a quarter centimetres on to ledge 50 which ledge then supports the stack. Thereafter, the dispensing operation is repeated.Because cam surface 32 comprises portions 32A and 32B, the effective cam surface is increased without causing major manufacture problems to the mould design and cooling operation. In this way sufficient vertical force can be applied to the rim of each cup [whether of low density in the case of foam cups or low rigidity as in the case of any cup (whether foam or thermoformed plastic or paper)] to ensure discharge of the lowermost cup from the stack without scoring or damaging the cup even when the cups are jammed together or strong electrostatic forces tend to keep the cups together. Figure 7a shows the cam profile of the dispenser as made in accordance with British Patent No. 2081238.The ledge 50 has a sharp front edge 60 and the distance between the upper surface of the ledge 50 and the part of the cam surface 32 which initially contacts the upper surface of the rim 51 of a cup is approximately the same as the height of the rim.

The cam profile as shown in Figure 7c has the distance between the upper surface 61 of the ledge 50 and the start of the cam surface 32a increased to be greater than the height of the rim. This means that some rotation will have to take place after the cam surface has entered the space between the lowermost rim and the rim immediately above it before it will contact the upper surface of the rim and this ensures that the ledge will have cleared the static before this contact takes place so that the rim cannot be crushed between these surfaces.

More importantly the ledge has been extended inwardly and formed with a front chamfered edge 62 corresponding to the upper chamfered side wall 63 of the cup. The relative dimensions of the ledges and cup are selected so that when the stack falls towards the ledges the first contact between the ledges and cups will be between the chamfered edges 62 and the chamfered upper side walls of the cups. This serves to slow down the cups, reduce the decelerating forces and reduce the shock loads thus causing less damage to the rims. In addition the engagement of these sloping surfaces tends to centre the stack to equalise the forces between the cams. There is a clearance 64 between the rim and ledge face 61 until the weight of the cup stack distorts the upper side wall radially, absorbs impact loads and "settles' in.

Claims (11)

1. A cup dispenser for dispensing foam cups one by one from a stack of cups, the dispenser comprising a plurality of injection moulded cam bodies of plastics material spaced about a first axis, co-axial with the axis of the stack of cups when present, each body comprising an outer wall of predetermined thickness having, a longitudinally extending axis parallel to the first axis, the body carrying a cam surface about the longitudinal axis of the body, drive means for rotating the cam bodies and thus the cam surfaces together, each of the cam surfaces being a helix about the axis of the body and arranged to engage the rim of the end cup of a stack of cups located in the dispenser so that rotation of the cam bodies in one direction pushes the lowest cup away from the remainder of the stack to dispense it, and in which each body carries a helically extending projection or bead about the body, the undersurface of the projection or bead presenting an extension of the cam face of each body to provide and enlarged cam face for providing a greater cup rim engaging cam surface than presented by the body itself, (i) the distance the projection extends from the wall of the cam body, (ii) the thickness between the top of the bead or projection and extension of the cam face from the wall of the cam body, and (iii) the thickness of the said wall of the body being such that on for mation of the body by injection moulding there is uniform cooling of the parts so that there is no distortion of the part when removed from the mould.

2. The dispenser of Claim 1, wherein the cam face of each cam body is chamfered throughout its entire length with respect to any diameter of the cam body at angle in the range 22 to 28 and preferably at substantially 25".

3. The dispenser of Claims 1 or 2, wherein the wall thickness of the body is in the range 2.5 to 3.5 mm, the distance the projection or bead extends from the cam body is in the range of .5 to 1.5 mm and the average distance between the top of the projection and the point where the cam surface starts to be covered by the projection is in the range 2 to 3 mm.

4. The dispenser of any of Claims 1 to 3 wherein (i) the distance the bead extends from the cam body is substantially 1 mm., (ii) the thickness between the top of the bead or projection and extension of the cam face from the wall of the body is substantially 2.5 mm., and (iii) the thickness of the side wall of the cam body is substantially 3 mm.

5. The dispenser of any of Claims 1 to 4, wherein each cam body also has an upwardly facing cam surface for engaging the next cup in the stack and holding up the stack as the lowermost cup is dispensed.

6. The dispenser of Claim 6, wherein the upwardly facing cam surface is chamfered with respect to any diameter in the range between 19 degrees and 26 degrees.

7. A dispenser according to Claim 5 or Claim 6 in which each cam has a ledge for supporting the lowermost cup and thus the stack between dispensing operations.

8. A dispenser according to Claim 7 in which the ledge and upper side wall of the cups are shaped and dimensioned such that when the stack initially falls at the end of a dispensing operation from a position supported by the upwardly facing cam surfaces to a position supported by the ledges, the initial contact between the ledges and the cups is between sloping parts of the upper cup wall and sloping parts of the front edges of the ledges.

9. A dispenser according to Claim 8 in which each upper side wall of each cup is formed with an under chamfer and the front edge of each ledge is formed with a corresponding chamfer, the chamfers preferably making an angle in the range 40 to 60 with the horizontal.

10. A dispenser according to any of Claims 5 to 9 in which the distance between the upper faces of the ledges and the lowermost parts of the dispensing cam surfaces is greater than the height of a cup rim.

11. A cup dispenser substantially as described herein with reference to or as illustrated in th accompanying drawings.