WO2003078124A1 - Mould and method for manufacturing a plastic chain element and a locking pinarrangement to be used therewith - Google Patents

Mould and method for manufacturing a plastic chain element and a locking pinarrangement to be used therewith Download PDF

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Publication number
WO2003078124A1
WO2003078124A1 PCT/DK2003/000144 DK0300144W WO03078124A1 WO 2003078124 A1 WO2003078124 A1 WO 2003078124A1 DK 0300144 W DK0300144 W DK 0300144W WO 03078124 A1 WO03078124 A1 WO 03078124A1
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WO
WIPO (PCT)
Prior art keywords
mould
pin
core
parts
stem
Prior art date
Application number
PCT/DK2003/000144
Other languages
French (fr)
Inventor
Poul Erik Dmakjaer
Original Assignee
Uni-Chains A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/179,303 external-priority patent/US6662938B2/en
Application filed by Uni-Chains A/S filed Critical Uni-Chains A/S
Priority to EP03711850A priority Critical patent/EP1490200A1/en
Priority to AU2003218624A priority patent/AU2003218624A1/en
Publication of WO2003078124A1 publication Critical patent/WO2003078124A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/0033—Moulds or cores; Details thereof or accessories therefor constructed for making articles provided with holes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/26—Moulds
    • B29C45/2628—Moulds with mould parts forming holes in or through the moulded article, e.g. for bearing cages
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G17/00—Conveyors having an endless traction element, e.g. a chain, transmitting movement to a continuous or substantially-continuous load-carrying surface or to a series of individual load-carriers; Endless-chain conveyors in which the chains form the load-carrying surface
    • B65G17/06—Conveyors having an endless traction element, e.g. a chain, transmitting movement to a continuous or substantially-continuous load-carrying surface or to a series of individual load-carriers; Endless-chain conveyors in which the chains form the load-carrying surface having a load-carrying surface formed by a series of interconnected, e.g. longitudinal, links, plates, or platforms
    • B65G17/08—Conveyors having an endless traction element, e.g. a chain, transmitting movement to a continuous or substantially-continuous load-carrying surface or to a series of individual load-carriers; Endless-chain conveyors in which the chains form the load-carrying surface having a load-carrying surface formed by a series of interconnected, e.g. longitudinal, links, plates, or platforms the surface being formed by the traction element
    • B65G17/086—Conveyors having an endless traction element, e.g. a chain, transmitting movement to a continuous or substantially-continuous load-carrying surface or to a series of individual load-carriers; Endless-chain conveyors in which the chains form the load-carrying surface having a load-carrying surface formed by a series of interconnected, e.g. longitudinal, links, plates, or platforms the surface being formed by the traction element specially adapted to follow a curved path
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G17/00—Conveyors having an endless traction element, e.g. a chain, transmitting movement to a continuous or substantially-continuous load-carrying surface or to a series of individual load-carriers; Endless-chain conveyors in which the chains form the load-carrying surface
    • B65G17/30—Details; Auxiliary devices
    • B65G17/38—Chains or like traction elements; Connections between traction elements and load-carriers
    • B65G17/40—Chains acting as load-carriers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/12—Chains
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G2207/00—Indexing codes relating to constructional details, configuration and additional features of a handling device, e.g. Conveyors
    • B65G2207/12—Chain pin retainers

Definitions

  • the present invention relates to a novel conveyor belt assembled from independent chain links by means of a locking pin arrangement such that the individual chain links can articulate relative to each other in at least two dimensions.
  • the locking pin arrangement may be constructed such that the chain links can be released by releasing and removing the locking pin.
  • the present invention relates to a method as well as a mould system for the manufacturing of plastic elements as well as a plastic element, said element having oppositely offset eye parts, where oppositely one eye part on one side of a core/stem is arranged a recess on the opposite side, where the manufactured plastic elements for example are chain links for conveyor belts and where the mould system comprises two mould halves such that each mould half comprises extending core/stem parts, where the core/stem parts are made with a taper and further that each plastic element manufactured by the method and by the mentioned mould system is a chain link, which is suitable for being assembled with other corresponding or identical chain links in order to create a flexible conveyor belt, where the element comprises a core/stem on both sides of which eye parts are arranged such that directly opposite an eye part on one side of the core/stem is arranged a corresponding recess on the opposite side such that two identical elements can be brought together and in this manner comprise overlapping eye parts such that a through-going aperture is provided in the chain link's transverse width
  • the invention also relates to a locking pin arrangement for releasably locking two or more chain links in a conveyor belt where the conveyor belt is made from a number of more or less identical chain links and that in each link there is arranged at least two eye parts extending on either side of a centre line of each chain link perpendicular to the intended travel direction of the belt, said at least two eye parts extending in the conveyor belt's travelling plane, and that in each eye part an aperture perpendicular to
  • CONRRMATION COPY the intended travel direction of the belt is provided such that the aperture of two adjacent linked eye parts may be superposed whereby a common aperture perpendicular to the intended travel direction of the conveyor belt is formed and that a pin is inserted in the common aperture.
  • Chain links are among other things used for constructing conveyors, which conveyors are relatively stiff in one dimension, usually the width, whereas they are very flexible in the transport direction. Furthermore, it can be achieved that the conveyor is very flexible for deflections in the conveyor's transport plane.
  • Chain belts of this type are used in a multitude of applications for transporting goods in production lines. Both in the food stuff industry and elsewhere.
  • Conveyors as well as chain links as described above are known from for example US 6216854.
  • the known conveyors are constructed by assembling a number of chain links which are mutually connected, where each chain link consists of a core/stem oriented in a transverse direction to the transport direction of the conveyor, and pro- truding from the core/stem in the plane of the conveyor eye parts are arranged.
  • a through-going aperture In every eye part perpendicular to the transport direction, approximately in the middle of the chain links' thickness, is arranged a through-going aperture.
  • the protruding eye parts on both sides of the core/stem are arranged in a offset manner, such that on one side of the core/stem an eye part is formed and directly opposite the eye part on the other side of the core/stem a recess is provided.
  • two chain links can be assembled such that the eye parts on one side of the core/stem fit into the recesses of an adjacent chain link.
  • the apertures formed in the eye parts in the thickness dimension will overlap such that one aperture is formed through the two assembled chain links transverse to the conveyor's transport direction.
  • an assembly pin is inserted into the overlapping apertures. If the aperture has an oval shape, it is possible for each separate chain link to move rela- tively to the adjacent chain links and at the same time stay connected to said chain links by means of the inserted assembly pins.
  • the conveyor Due to this possibility of relative displacement between two adjacent chains links, it becomes possible for the conveyor to be side-flexible in a direction parallel to the plane of the conveyor. Furthermore, as each chain link can rotate around the inserted assembly pin, the conveyor obtains a large degree of flexibility in a plane perpendicular to the conveyor's travelling direction.
  • apertures which extend through the eye part in a direction from one side of the conveyor belt to the opposite side.
  • this type of plastic element is usually carried out by a plastic moulding process, for example injecting moulding, where the element is cast in a lying position.
  • a plastic moulding process for example injecting moulding, where the element is cast in a lying position.
  • lying is in this connection to be understood that the mould is shaped such that when the two halves of the mould are closed and forced together, each separate chain link is cast such that the transport plane of the chain link, i.e. the plane where an assembly of elements constitute a conveyor belt, is perpendicular to the closing direction of the mould.
  • a number of pin bolts are inserted into the mould corresponding to the number of apertures which need to be formed in each chain link in order to provide the apertures in the thickness dimension for the later assembly of the chain links into a conveyor as discussed above.
  • the mass is introduced into the mould under high pressure, just as the two mould halves are forced together with a very high pressure, typically from about fifty to hundreds of tonnes. With this pressure a number of chain elements can be formed in each mould. This means that more elements are manufactured in one moulding cycle.
  • the pin bolts are withdrawn. Next the two mould halves are moved apart and the finished plastic elements are thereby released.
  • moulds for this type of element is relatively large as the mould consists of the width of the elements plus the length of the pin bolts, which usually corre- sponds to the width of the elements, since one pin bolt has to create openings throughout the eye parts in the entire width of an element in the thickness dimension in order to be able to assemble the chain links into a conveyor belt as discussed above.
  • Fur- thermore in the end of the pin bolts it is necessary to arrange hydraulic cylinders which can insert the pin bolts and withdraw the pin bolts again after the plastic mass has been introduced into the mould.
  • the space requirements for the mould is substantially larger than the size of the element.
  • a chain link a conveyor chain and a method for producing said chain links.
  • the chain links are in the lying down position and the mould parts are brought together in order to create the large apertures perpendicular to the conveyor belt's travelling direction. These apertures are provided in order to be able to have a large flow of air through the conveyor belt in order to cool objects placed on the conveyor belt.
  • traditional pin bolts are used with the inherent problems as discussed above. Turning back to the discussion of the locking pin arrangement there are certain disadvantages in the art.
  • transverse pin In order to maintain the transverse pin in its position in the apertures between two chain links it is customary to provide inserts which are to be fitted through corresponding apertures arranged in each side of the chain link.
  • the trans- verse pin is hereby kept in place in the apertures between two opposing inserts.
  • transverse pin or a chain link needs to be replaced, e.g. due to wear, breakage, or the like, this is done by forcing the inserts out of the engagement in the openings provided in each side of the belt and thereafter pulling out the transverse locking pin. If one link has to be removed this necessitates that two transverse pins have to be removed, which in turn means that four inserts have to be taken out. Thereafter, a new chain link is fitted, and inserts and corresponding transverse locking pins are reinserted and locked in position by the inserts.
  • Conveyor belts of the type mentioned above having locking inserts in both sides of the conveyor belt in order to keep the transverse pin engaged in a hinge like manner and connecting to adjacent chain links have a number of drawbacks.
  • One object of the present invention is to improve and simplify the moulds for the casting process of the elements and the same time reduce the requirements to the size of the injection mould machine.
  • the mould for the moulding process comprises two halves with protru- sions/core/stem parts which are moved into a position where the protrusions/core/stem parts are arranged in a side-by-side manner prior to injecting the moulding material;
  • protrusions/core/stem parts on one mould half create the recesses between neighbouring eye parts on one side and the cavity inside the oppositely arranged eye parts on the other side of the core/stem; - that the ultimate ends of the protrusions/core/stem parts on a first mould half during closing/injection are brought into contact with the side-by-side arranged interior ends of the protrusions/core/stem parts on the other mould part, and
  • the chain links have a top side on which the goods to be transported on the conveyor will be placed.
  • the bottom side is opposite the top side.
  • In relation to the transport direction of the conveyor or the direction perpendicular to the travelling direction is the width of the conveyor or chain link respectively.
  • the moulds By designing the moulds such that the cores/stems for the eye parts in a first mould half are offset in relation to the second mould half, where the cores/stems have corre- sponding side surfaces which during the casting process are in abutment such that the mould in its closed condition has contact points between the two mould halves.
  • the pin bolts which in the prior art created the apertures in the third dimension become superfluous. This results in a number of advantages.
  • pin bolts used in traditional moulds for forming of the apertures become worn.
  • This creep will cause the plastic to adhere to the pin bolts and due to the withdrawal of the pin bolts this will cause wear on the pin bolts.
  • This friction wear on the pin bolts means that the apertures in the elements will have a varying size during the production process whereby the tolerances between separate chain links will vary which can have substantial influence on the life expectancy of the finished conveyor belt.
  • the wear on the pin bolts can result in that the apertures in each element can vary and possibly induce casting errors in the eye parts of the ele- ments which can also influence the function of the conveyor belt in a negative direction.
  • the plastic elements are arranged in the mould such that the elements are placed standing up during the injection moulding process in relation to the closing direction of the mould.
  • standing up shall be understood as the plane wherein the elements in the use condition, i.e. if chain links as discussed above are being produced, will be assembled (the transport plane) in order to constitute an conveyor.
  • Standing up will therefore be the transport plane of the finished conveyor. This plane is perpendicular to the thickness plane as well as the width plane of the elements.
  • the width of an element is understood the width of a conveyor belt assembled from chain links.
  • the closing pressure on the moulds can be substantially reduced in that the surface (the thickness/width of the element which creates the counter pressure on the mould halves) can be substantially reduced in comparison to the traditional method, where the length/width of the elements will determine the closing pressure of the mould.
  • a plastic element according to the invention is substantially different from the known type of chain link in that the core/stem is penetrated approximately in the middle of the thickness direction, so that from a recess on one side of the core/stem an opening through the core/stem into the oppositely positioned eye part is created.
  • the core/stem with the breakthroughs still have the necessary strength, but a substantial savings on materials is achieved in that the core/stem in the thickness direction of a plastic element according to the invention is comparable to a lattice structure.
  • This lattice struc- ture comprises the plastic elements' outer surfaces and interior connection members which are arranged between the outer surfaces of the plastic element and is placed between recesses and oppositely arranged eye parts.
  • the said connection members constitute the limits of the through-going apertures in the eye parts towards the core/stem part.
  • the invention furthermore provides a locking pin arrangement for releasably locking two chain links in a conveyor belt wherein the pin has a generally cylindrical shape where the diameter corresponds to a minimum dimension of the aperture and that at least a section of the pin has a hollow section in the pin's longitudinal direction and that further at least two wing sections protrude outside the pin's cylindrical hollow section.
  • the pin is therefore very easy to install the pin into the overlapping apertures as this is done by simply forcing the pin through the overlapping apertures until the wings are not being constricted by the interior size of the apertures where after the pin and thereby the wings will slip back into their original section and be locked.
  • the pin is removed by depressing the wing section and thereby deforming the cross section of the pin in the area with the hollow section such that the wings are constricted enough to pass through the interior space in the apertures.
  • the pin can easily be pulled out of the chain links.
  • the wings are arranged at a longitudinal distance from one end of the pin corresponding to the width of an eye part perpendicular to the intended travel direction of the belt.
  • the pin has a hollow cross section in its entire longitudinal direction.
  • This embodiment of the invention is especially advantageous in applications where a high degree of hygienic standard is required such as in the food processing industries.
  • the pin is hollow, it is possible during the cleaning operations to completely flush in and around the pin whereby it can be avoided that food stuffs and thereby bacteria, moulds and the like will accumulate in the chain links.
  • the hollow pin has some advantages in that it can be produced by an injection moulding process where the pin is moulded around the core/stem member which during the process is removed in order to create the hollow cross section.
  • these can also be manufactured in an injection moulding process with a comparable setup.
  • the pin is made from the same material as the chain links or from a flexible plastic material.
  • the pin is made from a substantially tougher material than the chain links, the wear due to the friction between the chain links and the pins will always occur in the chain links and failure will therefore also occur in the chain link.
  • the pin can also be made from a plastic material, preferably a flexible plastic material in that especially for applications where this type of pin is used in side-flexing conveyor belts, the horizontal movements of the separate chain links will benefit from a certain degree of flexibility in the pin member.
  • the invention also provides an assembly system wherein the side flexing conveying belt is assembled with the locking arrangement comprising oval openings and a trans- verse pin, wherein it is possible to clean around the transverse pin in all the openings.
  • the stiff head portion of the transverse pin which becomes engaged in an eye portion immediately adjacent the slit, see further explanation below, does not give rise to any hygienic circumstances which could pollute or infect the produced foodstuffs.
  • conveyor belts of this type are fragile, is in transporting of persons, e.g. in connection with assembly lines, for example when assembling engines in car assembly plants or other industrial complexes, where the workers are transported alongside the goods to be produced. If a person drops an item and if the item is small enough it will have a tendency to become stuck between the separate chain links in the conveying belt.
  • a conveying belt with eye parts and intervals the open spaces, where parts can become stuck, are very limited in that the entire surface of the conveying belt save limited tolerance spaces between two chain links, is more or less solid. It is therefore much more difficult for foreign objects to become lodged between the separate chain links.
  • Fig. 1 is a perspective view of a conventional chain link
  • Fig. 2 illustrates a perspective view of a chain link according to the invention.
  • Fig. 3 illustrates two adjacent chain links
  • Fig. 4 illustrates a pin according to the invention
  • Fig. 5 illustrates an assembly detail between two chain links assembled with a pin.
  • Fig. 6 illustrates a section of a conveyor belt according to the invention
  • Fig. 7 illustrate chain links suitable to be assembled by a locking arrangement according to the invention
  • Fig. 8 illustrates a transverse pin according to the invention
  • Fig. 9 illustrates a detail of the notch and head portion of the transverse pin.
  • a chain link produced according to the traditional method The element 1 has a core/stem 2 from which eye parts 3 protrude in the travelling direction of the conveyor belt. Due to different requirements recesses 4 can be arranged in the eye parts 3 perpendicular to the surface which constitutes the conveyor belt.
  • apertures 5,6 are arranged in the thickness dimension of the chain link perpendicular to the transport direction of the conveyor belt and approximately in the middle of each chain link's thickness dimension through respectively the protruding eye parts on one side on the core/stem and on the other side of the core/stem.
  • the aperture 5 on one side of the core/stem is in the shape of a circular hole, while the aper- tures 6 on the other side of the core/stem are in the shape of elongated holes.
  • the eye parts with round holes are inserted in-between the eye parts with elongated apertures.
  • an overlap between the round holes 5 and the oval aperture 6 is achieved.
  • a round axle is inserted, said axle having an outer dimension substantially corresponding to the diameter of the holes 5. Due to the shape of the elongated holes 6 the chain links will be able to move relatively to each other in the conveyor belt's transport direction. Furthermore, the chain link may be sideways flexible in the plane of the conveyor belt.
  • fig. 2 is illustrated the corresponding element as illustrated with respect to the description of fig. 1, but manufactured according to the method disclosed in the present invention.
  • recesses are created in the eye parts 14 perpendicular to the plane of the conveyor belt.
  • From the core/stem 12 project eye parts 14 offset arranged such that on one side of the core/stem 12 is arranged an eye part 14 and directly on the opposite side of the core/stem 12 a recess 20 is provided.
  • a number of elements 10 can be assembled into a conveyor belt by inserting the eye part 14 into the recess 20 and thereafter insert an axle/locking pin through the overlapping openings 16,18. In this manner a flexible conveyor belt can be constructed exactly as explained above with reference to fig. 1.
  • the mould according to the invention for manufacturing of the elements for example as illustrated with reference to fig.
  • the surface which created the counter pressure when closing the two mould halves will be substantially less in that it will only be the width of the eye parts multiplied by the thickness of the element t which will create the counter pressure against the mould halves, whereas with the manufacturing process for an element as illustrated in fig. 1 it will be the entire surface of all the eye parts 3 as well as the core/stem 2 which will create the counter pressure against the mould halves.
  • the chain links produced according to the invention are lighter, but have equal strength in the use situation as compared to chain links manufactured according to the traditional method. This also provides some important advantages. As the chain links are lighter with the same strength, the force needed to activate the entire conveyor is less, which for lighter voluminous goods results in a lower energy consump- tion. For smaller items it becomes possible to increase the effective load on the conveyor without increasing the power consumption.
  • chain links which chain links by assembling a number of corresponding or identical chain links can be made into the shape of a flexible conveyor belt. It should, however, be understood that the invention is not limited to chain links of the type mentioned above, but the method for manufacturing of plastic elements according to the invention can be utilized in other plastic element producing processes, where recesses in three dimensions are needed and which are to be manufactured in a great number.
  • the method according to the invention is especially developed with respect to plastic moulding processes such as injection moulding of plastic, but can also be used in other plastic forming processes where moulds comprising two parts are used.
  • the conveyor belt consists of a number of substantially identical chain links 10.
  • the chain links are assembled and intended for travel in the direction indicated by the arrow A.
  • Each chain link is equipped with a number of eye parts 14 arranged on either side of a centre line perpendicular to the travel direction.
  • each eye part there is provided an aperture perpendicular to the travel direction in the belt's plane.
  • the locking pin has a cylindrical shape in the longitudinal direction. At a certain distance from the end of the pin, wings 26 are provided. The wings protrude outside the cylindrical cross section of the pin member 24. As at least a part of the pin in its longitudinal direction is hollow, it will be possible during insertion of the pin into the mutually over- lapping eye parts' apertures to deform the wings 26 such that the pin can be completely inserted in the apertures.
  • an indentation 28 can be provided on the pin in which an identification code or the like can be stamped onto the plastic member.
  • the shape of the wing as illustrated in Fig. 4 is such that for insertion purposes the side of the wing first engaging the aperture will be equipped with a chamfered side and the side hindering removal of the wing can be shaped as a side perpendicular to the longitudinal direction of the pin. By this configuration it becomes easy to push in the pin whereas removal is hampered by the side of the wing perpendicular to the longitudinal direction.
  • FIG. 5 a close-up of the assembly between two chain links 1 is shown.
  • the eye parts 3 overlap whereby the apertures provided in the eye parts also overlap and allow for the insertion of a locking pin 24 according to the invention.
  • the locking pin 24 is completely inserted into the apertures such that the end of the pin 24 is flush with the outside side edge 30 of the assembly conveying belt.
  • the wing sections 26 have expanded into a free space 32 provided between two adjacent eye parts 14 in the adjacent chain links. By this expansion into the free space 32, the wings 26 have attained a diameter larger than the diameter of the pin. The pin is thereby locked in its inserted position.
  • the wings 26 When wanting to remove the pin 4 from the apertures provided between the chain links 10, the wings 26 should be constricted by pressing on the side of the wings in the free space 32 such that the diameter of the wings 26 becomes equal to or less than the interior minimum diameter of the apertures provided in the eye parts 14.
  • a flexible conveyor belt is built up of a number of more or less identical chain links 10.
  • the chain links see Fig. 7a and b, each comprise a core/stem 12.
  • the eye parts are separated by recesses/openings 20, where each recess 16 has a width perpendicular to the intended travel direction A (see Fig. 6) of the conveyor belt, which is slightly larger than the width of an eye part.
  • the openings 16,18 in respective eye parts hereby becomes overlapping, such that a transverse pin as illustrated in Fig. 8 can be inserted through the openings in two chain links brought into the above described overlapping relationship with respect to their openings 16, 18.
  • the diameter of the transverse pin must be smaller or equal to the diameter of the openings 16,18, so that the transverse pin can be accommodated in the openings 16,18.
  • the transverse pin is a substantially cylindrical member, which has a length equal to the width of the conveyor belt, into which it is intended to be fitted.
  • the width of a conveyor belt is defined as the direction perpendicular to the travel direction A of a con- veyor belt as indicated in Fig. 1 or 6.
  • means are provided which can engage with corresponding means in a chain link as illustrated in Fig. 7a or 7b.
  • the chain link is further provided with a slit 34 in an outmost portion of the chain link, i.e. in the outmost eye part.
  • the slit is a continuous slit going from the top side of the conveying belt following the curvature of the eye part and ending in the bottom part.
  • a slit 34 is provided in both ends of the chain link, thereby making it possible to insert a transverse pin 32 as illus- -rated in Fig 8, which pin can engage with the slit from either side of the conveying belt.
  • the transverse pin 32 is illustrated in Fig. 8 equipped with the means for releasably locking into the slits 34 of the chain links 10.
  • These locking means consist of one or more notches and a head portion as illustrated in Fig. 9, which is a detail of Fig. 8.
  • the notch 36 is in this embodiment illustrated as a rectangular member.
  • the notch can be shaped in any suitable way, such that insertion into the end part of a chain link and engagement with the corresponding slit will be facilitated.
  • the end of the pin 32 is provided with a groove 38, whereby a hand tool, as for example a screw driver, can be inserted and assist in the twisting of the pin 32 during insertion of the pin into the overlapping apertures 16, 18 of adjacent chain links 10.
  • a hand tool as for example a screw driver
  • the pin In order to maintain the pin 32 in a non-rotating relationship with the chain link 10 the pin is provided with an extended head portion 40.
  • This head portion has a size which makes it possible for the entire head portion to be inserted in between the upper and lower part 42,44 (see Fig. 6), such that the head part 40 will be lodged and held against rotation in said opening.
  • one transverse pin having an extended head portion 40 is lodged inside the outermost eye portion between the upper surface 42 and the lower surface 44 in non-rotating engagement with the chain link. In this position the notch 36 will have engaged the slits 34, such that it is difficult to slide the pin 32 out of the direction of the conveyor belt during normal operation.
  • the bevelled surface engagement with the notch will cause the upper and lower part 42,44 of the eye part 14 to widen, whereby it becomes possible to force the notches so far into the eye part 14 that the notches 36 will be engaged in the slits 34.
  • the notches 36 have a size corresponding to the slits 34, such that they can be accommodated inside the slits with a minimum tolerance. Hereby is assured that the pin comprising the notches will not slide out through the openings during normal operation of the conveyor belt.

Abstract

The present invention relates to a method and a mould for manufacturing a plastic element having oppositely arranged eye parts where oppositely one eye part in relation to a substantially centrally placed core/stem is arranged a recess on the opposite side, for example chain links or a conveyor belt. This is achieved by a method where the mould comprises two halves with offset and side placed core/stem parts, which create recesses between side placed eye parts on one side and cavities on the oppositely arranged eye parts, where the ultimate ends of the core/stem parts on one mould half is brought into contact with side placed places interior parts of the core/stem parts on the other mould part by closing the two-part mould. In this manner, pin bolts which until now have shaped the openings in the third dimension become superfluous.

Description

MOULD AND METHOD FOR MANUFACTURING A PLASTIC CHAIN ELEMENT AND A LOCKING PINARRANGEMENT TO BE USED THEREWITH
Technical field of the invention
The present invention relates to a novel conveyor belt assembled from independent chain links by means of a locking pin arrangement such that the individual chain links can articulate relative to each other in at least two dimensions. The locking pin arrangement may be constructed such that the chain links can be released by releasing and removing the locking pin.
Furthermore, the present invention relates to a method as well as a mould system for the manufacturing of plastic elements as well as a plastic element, said element having oppositely offset eye parts, where oppositely one eye part on one side of a core/stem is arranged a recess on the opposite side, where the manufactured plastic elements for example are chain links for conveyor belts and where the mould system comprises two mould halves such that each mould half comprises extending core/stem parts, where the core/stem parts are made with a taper and further that each plastic element manufactured by the method and by the mentioned mould system is a chain link, which is suitable for being assembled with other corresponding or identical chain links in order to create a flexible conveyor belt, where the element comprises a core/stem on both sides of which eye parts are arranged such that directly opposite an eye part on one side of the core/stem is arranged a corresponding recess on the opposite side such that two identical elements can be brought together and in this manner comprise overlapping eye parts such that a through-going aperture is provided in the chain link's transverse width direction.
The invention also relates to a locking pin arrangement for releasably locking two or more chain links in a conveyor belt where the conveyor belt is made from a number of more or less identical chain links and that in each link there is arranged at least two eye parts extending on either side of a centre line of each chain link perpendicular to the intended travel direction of the belt, said at least two eye parts extending in the conveyor belt's travelling plane, and that in each eye part an aperture perpendicular to
CONRRMATION COPY the intended travel direction of the belt is provided such that the aperture of two adjacent linked eye parts may be superposed whereby a common aperture perpendicular to the intended travel direction of the conveyor belt is formed and that a pin is inserted in the common aperture.
Background of the invention
Chain links are among other things used for constructing conveyors, which conveyors are relatively stiff in one dimension, usually the width, whereas they are very flexible in the transport direction. Furthermore, it can be achieved that the conveyor is very flexible for deflections in the conveyor's transport plane.
Chain belts of this type are used in a multitude of applications for transporting goods in production lines. Both in the food stuff industry and elsewhere.
Conveyors as well as chain links as described above are known from for example US 6216854. The known conveyors are constructed by assembling a number of chain links which are mutually connected, where each chain link consists of a core/stem oriented in a transverse direction to the transport direction of the conveyor, and pro- truding from the core/stem in the plane of the conveyor eye parts are arranged. In every eye part perpendicular to the transport direction, approximately in the middle of the chain links' thickness, is arranged a through-going aperture. Furthermore, the protruding eye parts on both sides of the core/stem are arranged in a offset manner, such that on one side of the core/stem an eye part is formed and directly opposite the eye part on the other side of the core/stem a recess is provided. By means of this construction two chain links can be assembled such that the eye parts on one side of the core/stem fit into the recesses of an adjacent chain link. When assembling the chain links in this manner, the apertures formed in the eye parts in the thickness dimension will overlap such that one aperture is formed through the two assembled chain links transverse to the conveyor's transport direction. In order to assemble the chain links into a conveyor belt, an assembly pin is inserted into the overlapping apertures. If the aperture has an oval shape, it is possible for each separate chain link to move rela- tively to the adjacent chain links and at the same time stay connected to said chain links by means of the inserted assembly pins.
Due to this possibility of relative displacement between two adjacent chains links, it becomes possible for the conveyor to be side-flexible in a direction parallel to the plane of the conveyor. Furthermore, as each chain link can rotate around the inserted assembly pin, the conveyor obtains a large degree of flexibility in a plane perpendicular to the conveyor's travelling direction.
In a number of instances it is desirable to be able to have an endless belt, which turns to the side or where it is possible to change elevation of the surface of the belt. It is in these circumstances desirable that the belt is able to flex in a sidewards direction. This can be achieved with the belt as disclosed in EP 0 931 736, which discloses a side- flexing conveyor belt built up of a number of chain links. Each chain link comprises a core/stem which extends from one side of the conveyor belt to the other side of the conveyor belt. On both sides of the core/stem in the lengthwise direction of the conveyor belt are arranged eye parts spaced with mutual intervals between them, and on the other side of the core/stem are corresponding eye parts with mutual intervals spaced in a staggered relationship, such that the eye parts on one side of the core/stem fit into the intervals between two eye parts on another chain link.
In the eye parts are provided apertures, which extend through the eye part in a direction from one side of the conveyor belt to the opposite side. By inserting one chain link such that the eye parts fit into the intervals between two eye parts in the other chain link the apertures arranged in both chain links will be superposed, i.e. overlapping, such that a transverse pin can be inserted through the openings in all the eye parts, and thereby link the two chain links together in a hinge like manner. With this arrangement the conveyor belt becomes flexible in one dimension, namely it can change elevation through the run of the belt. By further shaping the apertures in the eye parts, e.g. by making them oval this will give rise to a certain play between two mutually linked chain links, whereby the conveyor belt becomes side-flexing.
The manufacture of this type of plastic element is usually carried out by a plastic moulding process, for example injecting moulding, where the element is cast in a lying position. By lying is in this connection to be understood that the mould is shaped such that when the two halves of the mould are closed and forced together, each separate chain link is cast such that the transport plane of the chain link, i.e. the plane where an assembly of elements constitute a conveyor belt, is perpendicular to the closing direction of the mould. After closure of the two mould halves, but prior to injection, a number of pin bolts are inserted into the mould corresponding to the number of apertures which need to be formed in each chain link in order to provide the apertures in the thickness dimension for the later assembly of the chain links into a conveyor as discussed above. For some applications two pin bolts are used, one in front and one in the back of each link such that each bolt traverses the entire link, in other applications four bolts are used such that two bolts in front are inserted from opposite sides and likewise two bolts are inserted from either side in the back of the link.
After insertion of the pin bolts into the mould, the mass is introduced into the mould under high pressure, just as the two mould halves are forced together with a very high pressure, typically from about fifty to hundreds of tonnes. With this pressure a number of chain elements can be formed in each mould. This means that more elements are manufactured in one moulding cycle. After the plastic mass has been forced into the mould, the pin bolts are withdrawn. Next the two mould halves are moved apart and the finished plastic elements are thereby released.
The dimension of moulds for this type of element is relatively large as the mould consists of the width of the elements plus the length of the pin bolts, which usually corre- sponds to the width of the elements, since one pin bolt has to create openings throughout the eye parts in the entire width of an element in the thickness dimension in order to be able to assemble the chain links into a conveyor belt as discussed above. Fur- thermore, in the end of the pin bolts it is necessary to arrange hydraulic cylinders which can insert the pin bolts and withdraw the pin bolts again after the plastic mass has been introduced into the mould. Hereby the space requirements for the mould is substantially larger than the size of the element. Furthermore, it is necessary to pro- vided a large force in order to force the two mould parts together, since the surface area of the elements in the mould's closing surfaces multiplied by the pressure in the plastic mass during the casting process result in a large pressure, which influences the mould halves with a relatively large resulting surface due to the orientation of the elements in the mould.
A similar casting process as discussed above with reference to the background art document US 6216854 is disclosed in WO 9738925. This conveyor is especially produced for providing good cooling to products placed on the conveyor. Therefore, the surface of the conveyor is perforated with rather large perforations such that the air easily can flow through the surface of the conveyor. During the moulding process, which is carried out according to the principles described above with respect to US 6216854, the two mould halves are brought into contact in order to provide the large recesses in the surface of the chain links. The apertures for inserting assembly pins as described above are manufactured in exactly the same way as the chain links disclosed in US 6216854 and further the element is arranged in the mould, i.e. lying, as disclosed above.
From WO 97/38925 is disclosed a chain link, a conveyor chain and a method for producing said chain links. In the method for manufacturing the chain links, the chain links are in the lying down position and the mould parts are brought together in order to create the large apertures perpendicular to the conveyor belt's travelling direction. These apertures are provided in order to be able to have a large flow of air through the conveyor belt in order to cool objects placed on the conveyor belt. For producing the apertures in the eye parts, traditional pin bolts are used with the inherent problems as discussed above. Turning back to the discussion of the locking pin arrangement there are certain disadvantages in the art. In order to maintain the transverse pin in its position in the apertures between two chain links it is customary to provide inserts which are to be fitted through corresponding apertures arranged in each side of the chain link. The trans- verse pin is hereby kept in place in the apertures between two opposing inserts.
If a transverse pin or a chain link needs to be replaced, e.g. due to wear, breakage, or the like, this is done by forcing the inserts out of the engagement in the openings provided in each side of the belt and thereafter pulling out the transverse locking pin. If one link has to be removed this necessitates that two transverse pins have to be removed, which in turn means that four inserts have to be taken out. Thereafter, a new chain link is fitted, and inserts and corresponding transverse locking pins are reinserted and locked in position by the inserts.
As these conveyor belts are often arranged in connection with complicated production equipment the work space is often somewhat limited and access to the point of breakage or the conveyor belt per se can be very cumbersome. Also for conveyor belts having a substantial width it is often necessary and advantageous to have two persons cooperating when replacing a chain link.
Conveyor belts of the type mentioned above having locking inserts in both sides of the conveyor belt in order to keep the transverse pin engaged in a hinge like manner and connecting to adjacent chain links have a number of drawbacks.
In the foodstuff industry there is an increasing demand for improved hygiene in connection with working, treating, and transporting foodstuffs. Furthermore, it is a requirement that there are as few parts as possible and absolutely no loose smaller parts, which can be enclosed in the produced foodstuffs from the machinery used for the manufacture of the foodstuffs. A second requirement is the hygienic standard, where it must be possible to thoroughly clean each and every single chain link in a manner, such that it is sufficiently safe that no unwanted bacteria or other pollution get an opportunity to fasten and develop themselves within the conveying belt structure. Summary of the mvention
One object of the present invention is to improve and simplify the moulds for the casting process of the elements and the same time reduce the requirements to the size of the injection mould machine.
This is achieved according to the present invention with a method which is particular in that the mould for the moulding process comprises two halves with protru- sions/core/stem parts which are moved into a position where the protrusions/core/stem parts are arranged in a side-by-side manner prior to injecting the moulding material;
- that the protrusions/core/stem parts on one mould half create the recesses between neighbouring eye parts on one side and the cavity inside the oppositely arranged eye parts on the other side of the core/stem; - that the ultimate ends of the protrusions/core/stem parts on a first mould half during closing/injection are brought into contact with the side-by-side arranged interior ends of the protrusions/core/stem parts on the other mould part, and
- that the mould halves after injection of mould material are withdrawn, whereby a through-going aperture through the eye parts in the chain links width direction is cre- ated.
In the description of the moulds above, ultimate end and interior end of the protru- sions/core/stem parts shall be understood such that the cores/stems protrude from the mould base. The mould base is adjacent the interior part within the terminology used in this application and the ultimate end of the core/stem is therefore the pinnacle of the protruding protrusion/core/stem part, i.e. the part of the protrusion/core/stem part furthest from the base.
Further, where reference is made to the travelling direction of the conveyor. This is understood as the direction in which the conveyor will transport goods placed on said conveyor. Also, distinction should be made between core parts of the mould and the chain links.
The chain links have a top side on which the goods to be transported on the conveyor will be placed. The bottom side is opposite the top side. In relation to the transport direction of the conveyor or the direction perpendicular to the travelling direction is the width of the conveyor or chain link respectively.
By designing the moulds such that the cores/stems for the eye parts in a first mould half are offset in relation to the second mould half, where the cores/stems have corre- sponding side surfaces which during the casting process are in abutment such that the mould in its closed condition has contact points between the two mould halves. The pin bolts which in the prior art created the apertures in the third dimension become superfluous. This results in a number of advantages. As the pin bolts neither need to be inserted nor drawn back, a moulding cycle can be completed faster and conse- quently there is a substantial saving in time by being able to cast the elements directly without the intermediate process of inserting, respectively removing, the pin bolts and furthermore the injection moulding machine can be manufactured cheaper in that the mould is substantially smaller and therefore does not require a large injection moulding machine.
As discussed above traditional moulds have a size corresponding to the width of the elements plus the length of the pin bolts plus the hydraulic cylinders necessary in order to be able to insert and withdraw pin bolts in order to create the apertures in the third dimension. According to the method of the present invention the pin bolts as well as the hydraulic cylinders can be excluded such that the entire mould size substantially corresponds to the width of the elements. Hereby it becomes possible to utilize substantially smaller injection moulding machines which in turn results in substantially lower production costs. Furthermore, the mould themselves become cheaper to manufacture in that they are smaller.
Yet another advantage achieved by being able to not use pin bolts in order to create the apertures in the third dimension is achieved in that pin bolts used in traditional moulds for forming of the apertures become worn. During the injection moulding process and during the hardening under high pressure the plastic has a tendency to creep up to 2 %. This creep will cause the plastic to adhere to the pin bolts and due to the withdrawal of the pin bolts this will cause wear on the pin bolts. This friction wear on the pin bolts means that the apertures in the elements will have a varying size during the production process whereby the tolerances between separate chain links will vary which can have substantial influence on the life expectancy of the finished conveyor belt. Furthermore, the wear on the pin bolts can result in that the apertures in each element can vary and possibly induce casting errors in the eye parts of the ele- ments which can also influence the function of the conveyor belt in a negative direction.
In a preferred embodiment of the invention the plastic elements are arranged in the mould such that the elements are placed standing up during the injection moulding process in relation to the closing direction of the mould. Within the scope of the present invention, standing up shall be understood as the plane wherein the elements in the use condition, i.e. if chain links as discussed above are being produced, will be assembled (the transport plane) in order to constitute an conveyor. Standing up will therefore be the transport plane of the finished conveyor. This plane is perpendicular to the thickness plane as well as the width plane of the elements. By the width of an element is understood the width of a conveyor belt assembled from chain links.
Furthermore, by producing the elements where these are standing up during the injecting moulding process the closing pressure on the moulds can be substantially reduced in that the surface (the thickness/width of the element which creates the counter pressure on the mould halves) can be substantially reduced in comparison to the traditional method, where the length/width of the elements will determine the closing pressure of the mould.
A plastic element according to the invention is substantially different from the known type of chain link in that the core/stem is penetrated approximately in the middle of the thickness direction, so that from a recess on one side of the core/stem an opening through the core/stem into the oppositely positioned eye part is created. The core/stem with the breakthroughs still have the necessary strength, but a substantial savings on materials is achieved in that the core/stem in the thickness direction of a plastic element according to the invention is comparable to a lattice structure. This lattice struc- ture comprises the plastic elements' outer surfaces and interior connection members which are arranged between the outer surfaces of the plastic element and is placed between recesses and oppositely arranged eye parts. The said connection members constitute the limits of the through-going apertures in the eye parts towards the core/stem part.
The invention furthermore provides a locking pin arrangement for releasably locking two chain links in a conveyor belt wherein the pin has a generally cylindrical shape where the diameter corresponds to a minimum dimension of the aperture and that at least a section of the pin has a hollow section in the pin's longitudinal direction and that further at least two wing sections protrude outside the pin's cylindrical hollow section.
With this type of pin it becomes possible to insert the pin into the overlapping apertures such that the wings will abut the interior surfaces on the apertures and deform until the wings have passed the first eye part where after the pin will snap back into its original position where the wings will protrude outside the cross section of the pin and thereby also hinder unintended removal of the pin from the overlapping apertures. The pin can deform when the wings are squeezed together passing through the apertures due to the hollow section in the longitudinal direction provided in the pin.
As explained above, it is therefore very easy to install the pin into the overlapping apertures as this is done by simply forcing the pin through the overlapping apertures until the wings are not being constricted by the interior size of the apertures where after the pin and thereby the wings will slip back into their original section and be locked. Likewise when having to remove the pin for replacement of a chain link or a section of the belt, the pin is removed by depressing the wing section and thereby deforming the cross section of the pin in the area with the hollow section such that the wings are constricted enough to pass through the interior space in the apertures. Hereby the pin can easily be pulled out of the chain links.
In a further advantageous embodiment of the invention, the wings are arranged at a longitudinal distance from one end of the pin corresponding to the width of an eye part perpendicular to the intended travel direction of the belt. In this manner, when the pin is inserted into a chain link and the wings have expanded again after passing an eye part, the end of the pin will be flush with the side of the conveyor belt. This gives a number of advantages in that cleaning of the belt which is very important in the food stuff industry as explained above becomes easier. Furthermore, as there are only very limited areas of the side of the conveyor belt which is not massive, the chance of foreign matter being stuck between the belt and the guidance track on which the belt usually runs is minimal. This improves the safety for workers working on or around the belt and also diminishes the chance of damage to the belt arising due to items such as paper, plastic or clothing becoming stuck between the belt and the guidance path.
In another preferred embodiment of the invention, the pin has a hollow cross section in its entire longitudinal direction. This embodiment of the invention is especially advantageous in applications where a high degree of hygienic standard is required such as in the food processing industries. When the pin is hollow, it is possible during the cleaning operations to completely flush in and around the pin whereby it can be avoided that food stuffs and thereby bacteria, moulds and the like will accumulate in the chain links.
Also from a production aspect the hollow pin has some advantages in that it can be produced by an injection moulding process where the pin is moulded around the core/stem member which during the process is removed in order to create the hollow cross section. For the other embodiments of the pin, these can also be manufactured in an injection moulding process with a comparable setup.
In a further preferred embodiment of the invention, the pin is made from the same material as the chain links or from a flexible plastic material. When choosing the ma- terials for the pins attention should be paid to what material the chain links in the belt are made from in that materials of the same type tend to work together better. If the pin is made from a substantially tougher material than the chain links, the wear due to the friction between the chain links and the pins will always occur in the chain links and failure will therefore also occur in the chain link. By choosing to make the pin from the same material it is assured that an even wear will appear in the belt whereby normal maintenance routines of the entire conveying system will detect excessive wear at normal maintenance intervals. The pin can also be made from a plastic material, preferably a flexible plastic material in that especially for applications where this type of pin is used in side-flexing conveyor belts, the horizontal movements of the separate chain links will benefit from a certain degree of flexibility in the pin member.
The invention also provides an assembly system wherein the side flexing conveying belt is assembled with the locking arrangement comprising oval openings and a trans- verse pin, wherein it is possible to clean around the transverse pin in all the openings.
Furthermore, the stiff head portion of the transverse pin, which becomes engaged in an eye portion immediately adjacent the slit, see further explanation below, does not give rise to any hygienic circumstances which could pollute or infect the produced foodstuffs.
In another application, where conveyor belts of this type are fragile, is in transporting of persons, e.g. in connection with assembly lines, for example when assembling engines in car assembly plants or other industrial complexes, where the workers are transported alongside the goods to be produced. If a person drops an item and if the item is small enough it will have a tendency to become stuck between the separate chain links in the conveying belt. By using a conveying belt with eye parts and intervals the open spaces, where parts can become stuck, are very limited in that the entire surface of the conveying belt save limited tolerance spaces between two chain links, is more or less solid. It is therefore much more difficult for foreign objects to become lodged between the separate chain links. Furthermore, should it occur that an object becomes stuck or fastened and causes damage to the conveying belt due to the releas- able structure of the transverse pins in connection with the chain links as described above it is possible to quickly and easily release the locking arrangement by twisting the transverse pins through the notches out of engagement with the slits in the chain links and thereby remove first the pin and thereafter the affected chain links. New links can very easily be inserted just by fitting them so that the openings in the eye parts overlap between the new and the old links and insert a transverse pin in the overlapping openings followed by a twisting of the transverse pins, such that the notches engage the slits in the chain links.
Brief description of the drawings
A more complete appreciation of the invention and many of the intended advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Fig. 1 is a perspective view of a conventional chain link;
Fig. 2 illustrates a perspective view of a chain link according to the invention.
Fig. 3 illustrates two adjacent chain links,
Fig. 4 illustrates a pin according to the invention, and Fig. 5 illustrates an assembly detail between two chain links assembled with a pin.
Fig. 6 illustrates a section of a conveyor belt according to the invention,
Fig. 7 illustrate chain links suitable to be assembled by a locking arrangement according to the invention,
Fig. 8 illustrates a transverse pin according to the invention, and Fig. 9 illustrates a detail of the notch and head portion of the transverse pin.
Description of embodiments
Referring to the drawings, wherein like reference numerals designate identical or cor- responding parts throughout and in particular in fig. 1, there is shown a chain link produced according to the traditional method. The element 1 has a core/stem 2 from which eye parts 3 protrude in the travelling direction of the conveyor belt. Due to different requirements recesses 4 can be arranged in the eye parts 3 perpendicular to the surface which constitutes the conveyor belt. In order to be able to assemble more chain links into a conveyor belt, apertures 5,6 are arranged in the thickness dimension of the chain link perpendicular to the transport direction of the conveyor belt and approximately in the middle of each chain link's thickness dimension through respectively the protruding eye parts on one side on the core/stem and on the other side of the core/stem. In the illustrated example the aperture 5 on one side of the core/stem is in the shape of a circular hole, while the aper- tures 6 on the other side of the core/stem are in the shape of elongated holes.
When assembling two identical chain links 1 the eye parts with round holes are inserted in-between the eye parts with elongated apertures. In this manner an overlap between the round holes 5 and the oval aperture 6 is achieved. Through the overlap- ping apertures a round axle is inserted, said axle having an outer dimension substantially corresponding to the diameter of the holes 5. Due to the shape of the elongated holes 6 the chain links will be able to move relatively to each other in the conveyor belt's transport direction. Furthermore, the chain link may be sideways flexible in the plane of the conveyor belt.
In fig. 2 is illustrated the corresponding element as illustrated with respect to the description of fig. 1, but manufactured according to the method disclosed in the present invention.
In the illustrated example recesses are created in the eye parts 14 perpendicular to the plane of the conveyor belt. From the core/stem 12 project eye parts 14 offset arranged such that on one side of the core/stem 12 is arranged an eye part 14 and directly on the opposite side of the core/stem 12 a recess 20 is provided. As explained above with reference to fig. 1 a number of elements 10 can be assembled into a conveyor belt by inserting the eye part 14 into the recess 20 and thereafter insert an axle/locking pin through the overlapping openings 16,18. In this manner a flexible conveyor belt can be constructed exactly as explained above with reference to fig. 1. The mould according to the invention for manufacturing of the elements, for example as illustrated with reference to fig. 2, will have engaging surfaces between the two mould halves corresponding to the openings 16,18. Where the mould closing direction for an element produced as described with reference to fig. 1 is illustrated by the arrow 8, the corresponding closing direction with respect to the new inventive method according to the invention is illustrated with the arrow 22.
As is evident from fig. 2 the surface which created the counter pressure when closing the two mould halves will be substantially less in that it will only be the width of the eye parts multiplied by the thickness of the element t which will create the counter pressure against the mould halves, whereas with the manufacturing process for an element as illustrated in fig. 1 it will be the entire surface of all the eye parts 3 as well as the core/stem 2 which will create the counter pressure against the mould halves.
Furthermore, the chain links produced according to the invention are lighter, but have equal strength in the use situation as compared to chain links manufactured according to the traditional method. This also provides some important advantages. As the chain links are lighter with the same strength, the force needed to activate the entire conveyor is less, which for lighter voluminous goods results in a lower energy consump- tion. For smaller items it becomes possible to increase the effective load on the conveyor without increasing the power consumption.
Contrary to the process known from the above mentioned document WO 97/38925 it is possible with the manufacturing process according to the present invention to manu- facture chain links which have a solid surface and still benefit from the manufacturing process as described above. The chain links known from WO 97/38925 will inherently, as a result of the process disclosed in the document, be provided with apertures in order to provide the cooling necessary for that process.
Above the invention has been described with respect to chain links, which chain links by assembling a number of corresponding or identical chain links can be made into the shape of a flexible conveyor belt. It should, however, be understood that the invention is not limited to chain links of the type mentioned above, but the method for manufacturing of plastic elements according to the invention can be utilized in other plastic element producing processes, where recesses in three dimensions are needed and which are to be manufactured in a great number.
The method according to the invention is especially developed with respect to plastic moulding processes such as injection moulding of plastic, but can also be used in other plastic forming processes where moulds comprising two parts are used.
Turning to Fig. 3 a section of a conveyor belt is illustrated. The conveyor belt consists of a number of substantially identical chain links 10. The chain links are assembled and intended for travel in the direction indicated by the arrow A.
Each chain link is equipped with a number of eye parts 14 arranged on either side of a centre line perpendicular to the travel direction. In each eye part there is provided an aperture perpendicular to the travel direction in the belt's plane. By inserting the eye part 14 of one chain link into the space between eye parts on an adjacent chain link, the apertures in the eye parts will overlap and create a thoroughgoing aperture from one side of the belt to the other side of the belt in a direction perpendicular to the trav- elling direction A of the entire belt and in the belt's travel plane. It will hereby become possible to insert a locking pin 24 into the overlapping apertures formed by the eye parts of adjacent chain links. The chain links 10 will hereby be assembled in a hingelike manner pivotably around the inserted locking pin 24.
Turning to Fig. 4 a locking pin 24 according to the invention is illustrated. The locking pin has a cylindrical shape in the longitudinal direction. At a certain distance from the end of the pin, wings 26 are provided. The wings protrude outside the cylindrical cross section of the pin member 24. As at least a part of the pin in its longitudinal direction is hollow, it will be possible during insertion of the pin into the mutually over- lapping eye parts' apertures to deform the wings 26 such that the pin can be completely inserted in the apertures. When the pin and the wings have passed so far through an aperture that an opening between two eye parts is met, the constriction caused by the aperture to the hollow section with the wings 26 on the pin will have disappeared and the pin in the hollow section will regain its cylindrical cross section whereby the wings will extend outside the pin's cylindrical cross section. The pin is therefore locked in this position and requires a positive action in order to release or withdraw the pin from this engaged position.
When the pin is made from a plastic material, it is customary to identify the material such that once the pin or other plastic members has completed its service life, it will be possible to identify the sort of plastic for recycling purposes. For this purpose an indentation 28 can be provided on the pin in which an identification code or the like can be stamped onto the plastic member.
The shape of the wing as illustrated in Fig. 4 is such that for insertion purposes the side of the wing first engaging the aperture will be equipped with a chamfered side and the side hindering removal of the wing can be shaped as a side perpendicular to the longitudinal direction of the pin. By this configuration it becomes easy to push in the pin whereas removal is hampered by the side of the wing perpendicular to the longitudinal direction.
Turning now to Fig. 5 a close-up of the assembly between two chain links 1 is shown.
The eye parts 3 overlap whereby the apertures provided in the eye parts also overlap and allow for the insertion of a locking pin 24 according to the invention. The locking pin 24 is completely inserted into the apertures such that the end of the pin 24 is flush with the outside side edge 30 of the assembly conveying belt. The wing sections 26 have expanded into a free space 32 provided between two adjacent eye parts 14 in the adjacent chain links. By this expansion into the free space 32, the wings 26 have attained a diameter larger than the diameter of the pin. The pin is thereby locked in its inserted position.
When wanting to remove the pin 4 from the apertures provided between the chain links 10, the wings 26 should be constricted by pressing on the side of the wings in the free space 32 such that the diameter of the wings 26 becomes equal to or less than the interior minimum diameter of the apertures provided in the eye parts 14.
In a further embodiment according to the invention a flexible conveyor belt is built up of a number of more or less identical chain links 10. The chain links, see Fig. 7a and b, each comprise a core/stem 12. On either side of the core/stem 12 there are eye parts 4 extending out from said core/stem and mutually offset on either side of the core/stem 12. The eye parts are separated by recesses/openings 20, where each recess 16 has a width perpendicular to the intended travel direction A (see Fig. 6) of the conveyor belt, which is slightly larger than the width of an eye part. Hereby it is possible to insert the eye parts of a second identical chain link into the corresponding recess 20 of a first chain link, as can be seen in Fig. 6. The openings 16,18 in respective eye parts hereby becomes overlapping, such that a transverse pin as illustrated in Fig. 8 can be inserted through the openings in two chain links brought into the above described overlapping relationship with respect to their openings 16, 18.
It is of course evident that the diameter of the transverse pin must be smaller or equal to the diameter of the openings 16,18, so that the transverse pin can be accommodated in the openings 16,18.
One example of a transverse pin according to the invention is illustrated in Fig. 8. The transverse pin is a substantially cylindrical member, which has a length equal to the width of the conveyor belt, into which it is intended to be fitted. The width of a conveyor belt is defined as the direction perpendicular to the travel direction A of a con- veyor belt as indicated in Fig. 1 or 6. In one end of the pin 32 means are provided which can engage with corresponding means in a chain link as illustrated in Fig. 7a or 7b. In Fig. 7a the chain link is further provided with a slit 34 in an outmost portion of the chain link, i.e. in the outmost eye part. In this embodiment the slit is a continuous slit going from the top side of the conveying belt following the curvature of the eye part and ending in the bottom part. Although not necessary a slit 34 is provided in both ends of the chain link, thereby making it possible to insert a transverse pin 32 as illus- -rated in Fig 8, which pin can engage with the slit from either side of the conveying belt.
The transverse pin 32 is illustrated in Fig. 8 equipped with the means for releasably locking into the slits 34 of the chain links 10. These locking means consist of one or more notches and a head portion as illustrated in Fig. 9, which is a detail of Fig. 8.
The notch 36 is in this embodiment illustrated as a rectangular member. The notch can be shaped in any suitable way, such that insertion into the end part of a chain link and engagement with the corresponding slit will be facilitated.
In order to facilitate this engagement the end of the pin 32 is provided with a groove 38, whereby a hand tool, as for example a screw driver, can be inserted and assist in the twisting of the pin 32 during insertion of the pin into the overlapping apertures 16, 18 of adjacent chain links 10.
In order to maintain the pin 32 in a non-rotating relationship with the chain link 10 the pin is provided with an extended head portion 40. This head portion has a size which makes it possible for the entire head portion to be inserted in between the upper and lower part 42,44 (see Fig. 6), such that the head part 40 will be lodged and held against rotation in said opening. As can be seen in Fig. 6 one transverse pin having an extended head portion 40 is lodged inside the outermost eye portion between the upper surface 42 and the lower surface 44 in non-rotating engagement with the chain link. In this position the notch 36 will have engaged the slits 34, such that it is difficult to slide the pin 32 out of the direction of the conveyor belt during normal operation. When having to remove a chain link due to wear, breakage, or breakage of a pin, this can be done by inserting e.g. a screw driver in the groove 38 twisting the screw driver, whereby the extended head portion 40 will cause the two parts 42,44 apart, whereby it becomes possible to release the notches 36 from the slits 34 and thereby withdraw the entire pin 32. When inserting a new pin into the overlapping openings 16,18 of two adjacent chain links this can be facilitated by providing a bevelled surface 46 as illustrated in Fig. 2b. When the pin 32 is pushed through the openings 16,18 the notches 36 will eventually come into sliding engagement with the bevelled surface 46. By further forcing the pin into the openings the bevelled surface engagement with the notch will cause the upper and lower part 42,44 of the eye part 14 to widen, whereby it becomes possible to force the notches so far into the eye part 14 that the notches 36 will be engaged in the slits 34. The notches 36 have a size corresponding to the slits 34, such that they can be accommodated inside the slits with a minimum tolerance. Hereby is assured that the pin comprising the notches will not slide out through the openings during normal operation of the conveyor belt.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appending claims the inventions may be practiced otherwise as specifically described herein.

Claims

1. Method for manufacturing of plastic elements having oppositely arranged offset eye parts, wherein there oppositely to an eye part on one side of a core/stem is ar- ranged a recess; where the manufactured plastic elements for example are chain links for a conveyor belt and where the method comprises; that the mould for the moulding process comprises two halves with protrusions/core/stem parts which are moved into a position where the protrusions/core/stem parts are arranged in a side-by-side manner prior to injecting the moulding material; that the protrusions/core/stem parts on one mould half create the recesses between neighbouring eye parts on one side and the cavity inside the oppositely arranged eye parts on the other side of the core/stem; that the ultimate ends of the protrusions/core/stem parts on a first mould half during closing/injection are brought into contact with the side-by-side arranged interior ends of the protrusions/core/stem parts on the other mould part, and that the mould halves after injection of mould material are withdrawn, whereby a through-going aperture through the eye parts in the chain links' width direction is created.
2. Method for manufacturing of plastic elements by plastic moulding according to claim 1 , wherein the mould halves are shaped such that the elements are moulded having the closing direction of the mould halves parallel to the elements' longitudinal direction/conveyor belt's transport direction.
3. Mould for manufacturing elements in a plastic moulding machine according to claim 1 and/or 2, wherein the mould comprises two mould halves, where each half comprises protruding mould parts, where the mould parts have a taper and wherein the core/stem parts in a first mould half are offset in relation to the other mould part such that the core/stem parts have corresponding ultimate side ends which during moulding are in engagement.
4. Mould for manufacturing elements in a plastic moulding machine according to claim 3, wherein the ultimate side edges on the protrusions/core/stem parts on a first mould half in the mould's closed position correspond to offset interior side surfaces on the protrusions/core/stem parts on the other mould half.
5. Element manufactured by a plastic moulding process in a two-part mould according to any of claims 1-4, where the element is a chain link, which chain link can be assembled with other corresponding or identical chain links and thereby create a flexible conveyor belt, where the chain link comprises a core/stem on both sides of which perpendicular to the transport direction of the chain link eye parts are provided such that directly opposite an eye part on the other side of the core/stem is arranged a corresponding recess such that two identical chain links can be pushed together and thereby have overlapping eye parts and where in the eye parts are arranged through-going apertures in the chain links with direction, wherein the core/stem is broken through such that from a recess on one side of the core/stem is created an opening into the oppositely arranged eye part on the other side of the core/stem.
6. Locking pin arrangement (24,32) for releasably locking two or more chain links (10) in a conveyor belt, where the conveyor belt is made from a number of more or less identical chain links, and that in each link (10) there is arranged at least two eye parts (14) extending on either side of a core or stem (12) perpendicular to the intended travelling direction (A) of the belt, said at least two eye parts (14) extending in the conveyor belts travelling plane, and that in each eye part an aperture (16,18) perpendicular to the intended travel direction (A) of the belt is provided, such that the aper- hire (16,18) of two adjacent chain links eye parts in a plane parallel to the plane of the belt may be superposed whereby a common aperture perpendicular to the intended travel direction of the conveyor belt, is formed, and that a pin (24,32) is inserted in the common aperture (16,18) where the pin has a generally cylindrical shape, where the diameter substantially corresponds to a minimum dimension of the aperture (16,18), and that means (26,36) are provided on the pin (24,32) which extends beyond the diameter for positively engaging means (32,34) provided in the chain links.
7. Locking pin arrangement according to claim 6, characterised in that at least a section of the pin has a hollow section in the pins longitudinal direction, and that further at least two wing sections protrudes outside the pins cylindrical hollow section.
8. Locking pin arrangement according to claim 7, characterised in that the wings are arranged at a longitudinal distance from one end of the pin corresponding to the width of an eye part peφendicular to the intended travel direction of the belt, and in that the cross section of at least one end of the pin is not hollow, or in that the pin has a hollow cross section in its entire longitudinal direction.
9. Locking pin arrangement according to claim 6, 7 or 8, characterised in that each chain link superposed with overlapping openings (16,18) is provided with at least one slit (34) oriented substantially peφendicular to the longitudinal direction of the transverse pin (32); each transverse pin (32) is provided with a head portion, and at least one notch (36) proximate the head, adapted for engagement with the slit (34) when the transverse pin (32) is inserted in the openings (16,18), and the outermost surface of the head portion is substantially flush with the edge of the link.
10. Locking pin arrangement according to claim 6, characterised in that the at least one slit is provided in an outer portion of each chain link, and in that a grove
(38) may optionally be provided in the head portion of the transverse pin (32) for aiding in twisting the notch (36) into the slit (34) and in that the notch may be in the shape of a prism, cylinder, cube, truncated cone or any other three-dimensional shape suitable for engagement with the slit.
11. Locking pin arrangement according to any of the claims 6-10, characterise d in that the edge of the opening adjacent the slit may be bevelled.
12. Locking pin arrangement according to any of the claims 6-11, characterise d in that a slit is provided in both sides of each chain link.
13. Locking pin arrangement according to claim 10, 11 or 12, characterised in that the head portion of the pin extends with a rectangular section peφendicularly to the longitudinal direction of the pin.
14. Locking pin according to any of the claims 6- 13, characterised in that the pin is made from the same material as the chain links or from a flexible plastic material.
15. Conveyor made from assembling chain links as disclosed in claim 5, manufac- hired according to any of claim 1 or 2 by means of a mould according to any of the claims 3 or 4, by means of a locking pin arrangement according to any of the claims 6- 14.
PCT/DK2003/000144 2002-03-08 2003-03-07 Mould and method for manufacturing a plastic chain element and a locking pinarrangement to be used therewith WO2003078124A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP03711850A EP1490200A1 (en) 2002-03-08 2003-03-07 Mould and method for manufacturing a plastic chain element and a locking pinarrangement to be used therewith
AU2003218624A AU2003218624A1 (en) 2002-03-08 2003-03-07 Mould and method for manufacturing a plastic chain element and a locking pinarrangement to be used therewith

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
DKPA200200353 2002-03-08
DKPA200200353 2002-03-08
US10/179,303 2002-06-26
US10/179,303 US6662938B2 (en) 2002-03-08 2002-06-26 Locking arrangement for releasably locking a transverse rod to a chain link
DKPA200201462 2002-10-01
DKPA200201462 2002-10-01

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Publication Number Publication Date
WO2003078124A1 true WO2003078124A1 (en) 2003-09-25

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EP (1) EP1490200A1 (en)
AU (1) AU2003218624A1 (en)
WO (1) WO2003078124A1 (en)

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EP1951602A1 (en) * 2005-11-08 2008-08-06 Ashworth Bros., Inc. Conveyor belt
GB2455808A (en) * 2007-12-22 2009-06-24 Lucy & Co Ltd W Electrical cut-out
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WO2017202862A1 (en) * 2016-05-24 2017-11-30 Habasit Ag Pin retention for conveyor modules
EP4227245A3 (en) * 2021-12-21 2023-10-25 Regina Catene Calibrate S.p.A. Curvilinear conveyor chain suitable for running along a guide comprising at least one curved section

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EP1951602A1 (en) * 2005-11-08 2008-08-06 Ashworth Bros., Inc. Conveyor belt
EP1951602A4 (en) * 2005-11-08 2012-03-28 Ashworth Bros Inc Conveyor belt
GB2455808A (en) * 2007-12-22 2009-06-24 Lucy & Co Ltd W Electrical cut-out
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EP3653544A1 (en) 2016-05-24 2020-05-20 Habasit AG Pin retention for conveyor modules
EP4227245A3 (en) * 2021-12-21 2023-10-25 Regina Catene Calibrate S.p.A. Curvilinear conveyor chain suitable for running along a guide comprising at least one curved section

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