Tonnage regulating structure and a mold incorporating same

Embodiments of the present invention are directed to a tonnage regulating structure and a mold incorporating same. For example, a tonnage regulating structure (302, 1002, 1202) for use in a mold (502) of a molding machine, the mold (502) being associated with an opening clearance (520) between mold faces in a mold closed and clamped configuration, is provided. The tonnage regulating structure (302) comprises a body (304, 1040, 1240) having a first height (306) in a resting configuration, the first height (306) selected to be larger than the opening clearance (520) between the mold faces in a mold closed and clamped configuration; the body (304, 1040, 1240) including a compensating structure (308), the compensating structure (308) for regulating, in use under applied clamp tonnage, the body (304, 1040, 1240) to a second height (320), the second height (320) being smaller than the first height (306).

FIELD OF THE INVENTION

The present invention generally relates to, but is not limited to, a molding system, and more specifically the present invention relates to, but is not limited to, a tonnage regulating structure and a mold incorporating same.

BACKGROUND OF THE INVENTION

Molding is a process by virtue of which a molded article can be formed from molding material by using a molding system. Various molded articles can be formed by using the molding process, such as an injection molding process. One example of the molded article that can be formed, for example, from polyethylene terephthalate (PET) material is a preform that is capable of being subsequently blow-molded into a beverage container, such as, a bottle and the like. Other examples of the molded articles include thin-wall containers (i.e. yogurt containers, cups, etc), medical appliances and the like.

In the early days of injection molding, a single-cavity mold for producing a single molded article per molding cycle was typically deployed. Within the single-cavity mold, typically, melt would be delivered from a plasticizing unit to a molding cavity, defined within the single-cavity mold, via a sprue. With developments in the injection molding art, multi-cavity molds have been introduced with an outlook to increase the number of molded articles manufactured per molding cycle. Typically, within the multi-cavity mold, the melt is delivered from the plasticizing unit to each of a plurality of molding cavities of the multi-cavity mold through a melt distribution network, also known to those of skill in the art, as a “hot runner”.

With ongoing market pressures on the converters (i.e. entities that convert raw material, such as resin, into a molded article, such as a preform, for example) to keep the output per capita and the operating costs under control (and, even better, to improve the output per capita ratio and decrease the costs), molding machine suppliers (such as, for example, Husky Injection Molding, Ltd of Bolton, Ontario, www.husky.ca) have progressively increased mold cavitation, effectively, increasing the number of molded articles that can be produced in a given molding cycle.

With further increases in cavitation, a term “tight pitch” has become widely used. The term denotes a mold having a relatively tight pitch between cavities. For example, Husky Injection Molding Systems, Ltd sells such molds under a trademark MICROPITCH. One problem that has been realized in the industry, which is particularly acute in the tight pitch molds, is irregular distribution of forces amongst various components of the mold in the mold clamped configuration. This is particularly exacerbated by the fact that even though mold stack components are produced to very tight tolerances, there are nevertheless minute differences in dimensions (such as for example, height thereof) that may significantly exacerbate the problem. This problem can be further exacerbated by lack of proper platen parallelism, platen deflection in use and the like.

Consider a given mold having 144 cavities and, accordingly, 144 mold stacks (including a molding cavity insert, a core insert, a neck ring pair and other associated molding components). A first given one of the 144 mold stacks may be slightly higher than a second given one of the 144 mold stacks. In this scenario, when full clamp force is exerted onto the mold, the first given one of the 144 mold stacks will experience deformation. This, in turn, can lead to premature wear, molding defects evident on molded articles and the like.

By adding more cavities into a mold, the available shut-off area is limited and usually falls below a given standard. This, in turn, requires adding shut-off area with external features. One solution pursued in the industry has been introduction of so-called “tonnage blocks”, which are primarily (but not exclusively) used on tight pitch molds. Generally speaking, the reason to add tonnage blocks to a mold is to increase the surface area in contact under clamp in order to prevent permanent deformation of the shut-off faces (also known as hobbing). The tonnage block generally comprises a structure inserted in-between complementary mold halves and is generally configured to absorb or re-distribute at least a portion of the clamp force.

US patent application 2007/0212443 published to Guoming, et al. on Sep. 13, 2007 discloses an injection mold including a connecting structure for separating confronting faces of a slide member and a mold base, respectively, during a movement of the slide member. In accordance with several embodiments of the invention, the connecting structure may include a compressible member such that the slide member is biased away from the mold base, and wherein a positive contact between the confronting surfaces is configurable in response to an applied clamping force between the slide member and the mold base. In accordance with an alternative embodiment of the invention a cam arrangement links the slide member and the mold base enabling a positive contact between the confronting surfaces when the slide member is arranged in the in-mold position, and providing a gap between the confronting surfaces during at least a portion of an interval when the slide member is moving. The patent application teaches inter alia a clamping force block 29, which is added (if necessary) to absorb clamping force A (FIG. 1), which goes through the mold stack when such clamping force is too high.

US patent application 2007/0292558 published to Irwine et al. on Dec. 20, 2007 discloses a hot-runner assembly for injection molding equipment. The hot-runner assembly includes a front plate and a backing plate spaced from one another so as to define an inter-plate volume. The inter-plate volume contains one or more manifolds for conducting flowable material to a plurality of injection nozzles. The inter-plate volume also contains inter-plate support distributed between a first inter-plate support zone located immediately adjacent the manifold(s) and a second inter-plate support zone that makes up the balance of the inter-plate volume so that the first inter-plate support zone has a inter-plate support footprint density that is greater than the inter-plate support footprint density in the second inter-plate support zone. This patent application teaches inter alia an inter-plate support 120.

US patent application 2007/0184148 published to Naoto, et al. on Aug. 9, 2007 discloses a mold for in-mold decorating simultaneously with molding manufacturable at low cost in a short delivery period in manufacturing the mold and capable of stably mass-producing molded article in molding the molded articles, wherein cavity forming blocks having molding cavities into which an in-mold decoration film is to be inserted are mounted on diesets on a fixed side and a movable side. Pockets into which the cavity forming blocks are fitted are not formed in the diesets, the diesets and cavity forming blocks are positioned by engaging projections formed on one of the contact faces thereof and engaging recesses formed in the other before installation, and a plurality of mold clamping force receiving parts are installed on the outside of a film passing area around the cavity forming blocks. This patent application teaches inter alia a plurality of clamping force-receiving portions 6a, 6b that are set partly around the cavity-forming blocks.

SUMMARY OF THE INVENTION

According to a first broad aspect of the present invention, there if provided a tonnage regulating structure for use in a mold of a molding machine, the mold being associated with an opening clearance between mold faces in a mold closed and clamped configuration, is provided. The tonnage regulating structure comprises a body having a first height in a resting configuration, the first height selected to be larger than the opening clearance between the mold faces in a mold closed and clamped configuration; the body including a compensating structure, the compensating structure for regulating, in use under applied clamp tonnage, the body to a second height, the second height being smaller than the first height.

According to a second broad aspect of the present invention, there is provided a mold for use in a molding machine. The mold comprises a cavity portion including a cavity side mold face) and a core portion including a core side mold face, the cavity portion and the core portion defining therebetween a molding cavity; the mold being associated with an opening clearance between the cavity side mold face and the core side mold face in a mold closed and clamped configuration, a tonnage regulating structure including: a body having a first height in a resting configuration, the first height selected to be larger than the opening clearance; the body including a compensating structure, the compensating structure for regulating, in use under applied clamp tonnage, the body to a second height, the second height being smaller than the first height.

According to a third broad aspect of the present invention, there is provided a tonnage regulating structure for regulating tonnage force distribution in a mold. The tonnage regulating structure comprises a body selectively actuatable between a resting height and an in-use height; the body including a compensating structure, the compensating structure being operable to allow the body to controllably selectively toggle between the resting height and the in-use height.

These and other aspects and features of non-limiting embodiments of the present invention will now become apparent to those skilled in the art upon review of the following description of specific non-limiting embodiments of the invention in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF EMBODIMENTS

Inventors have developed embodiments of the present invention based, at least partially, on a realization that there exists at least one problem associated with prior art tonnage regulating structures. This problem will now be illustrated for the benefit of the reader with reference toFIG. 1AandFIG. 1B, as well asFIG. 2AandFIG. 2B. It should be expressly noted that illustrations inFIG. 1A,FIG. 1B,FIG. 2AandFIG. 2Bare schematic for the purposes of illustration of prior-art problems only, but it is expected that those of ordinary skill in the art will appreciate actual implementations of the components to be described herein below.

FIG. 1AandFIG. 1Bshow a scenario where a tonnage regulating structure is shorter than it should be. More specifically,FIG. 1Aschematically depicts a first mold half102and a second mold half104and disposed therebetween a plurality of molding stacks106. The first mold half102is associated with a first mold face103and the second mold half104is associated with a second mold face105.

It is evident fromFIG. 1Athat some of the plurality of molding stacks106are dimensioned (length-wise) differently from others of the plurality of molding stacks106, these differences in dimensions being greatly exaggerated, for illustration purposes only, inFIG. 1A. For example, a first molding stack106ais longer than a second molding stack106b. By the same token, the second molding stack106bis longer than a third molding stack106c.FIG. 1Afurther depicts two instances of a tonnage regulating structure108disposed between the first mold half102and the second mold half104, the two instances of the tonnage regulating structure108being implemented according to known techniques. In this scenario, it happens that despite very strict production tolerances, the tonnage regulating structure108is dimensioned somewhat shorter than the first molding stack106aand somewhat longer than the third molding stack106c, again these differences being greatly exaggerated inFIG. 1Afor the purpose of illustration.

FIG. 1Billustrates the net result of these differences in length when at least a portion of clamp tonnage “A” is applied (in a manner known in the art, the clamp tonnage “A” can be generated by a suitable hydraulic clamp, electric clamp, toggle clamp or the like). Within the illustration, it can be clearly seen that the first molding stack106ais deformed under the applied clamp tonnage “A”. Furthermore, it is clear that there exists a gap “G1” between the tonnage regulating structure108and the second mold face105. In other words, the two instances of the tonnage regulating structure108fail to perform their function of absorbing a portion of the load and, at the same time, the first molding stack106aand, eventually, the second molding stack106b(when the full clamp force “A” is exerted) will get deformed, which will lead over time to premature wear, etc.

By the same token, a problem can occur when a tonnage regulating structure is longer than it should be. This will now be demonstrated with reference toFIG. 2AandFIG. 2B.

More specifically,FIG. 2Aschematically depicts a first mold half202and a second mold half204and disposed therebetween a plurality of molding stacks206. The first mold half202is associated with a first mold face203and the second mold half204is associated with a second mold face205.

It is evident fromFIG. 2Athat some of the plurality of molding stacks206are dimensioned (length-wise) differently from others of the plurality of molding stacks206, these differences in dimensions being greatly exaggerated, for illustration purposes only, inFIG. 2A. For example, a first molding stack206ais longer than a second molding stack206b. By the same token, the second molding stack206bis longer than a third molding stack206c.FIG. 2Afurther depicts two instances of a tonnage regulating structure208disposed between the first mold half202and the second mold half204, the two instances of the tonnage regulating structure208being implemented according to known techniques. As it happens, despite very strict production tolerances, the tonnage regulating structure208is dimensioned somewhat longer than the first molding stack206a, the second molding stack106band the third molding stack106c, again these differences being greatly exaggerated inFIG. 2Afor the purposes of illustration.

FIG. 2Billustrates the net result of these differences in length when at least a portion of clamp tonnage “A” is applied (in a manner known in the art, the clamp tonnage “A” can be generated by a suitable hydraulic clamp, electric clamp, toggle clamp or the like). Within the illustration, it can be clearly seen that the two instances of the tonnage regulating structure208are deformed, even though the second mold face205just abuts the first molding stack206aand is still spaced away from the second molding stack206band the third molding stack206cby respective distances, which are not separately numbered. Assuming that the clamp force “A” depicted inFIG. 2Bis only a partial clamp force and upon further application of the clamp force “A”, the two instances of the tonnage regulating structure208will be further deformed, leading to potential failure to perform their function. It is also noted that in this prior art implementation, deformation and extent of deformation of the tonnage regulating structure208is uncontrollable by the operator/user. In other words, the extent of deformation will depend on the relationship between the height of the tonnage regulating structure208and the various components of the molding stack206.

With reference toFIG. 3, there is depicted a non-limiting embodiment of a tonnage regulating structure302implemented in accordance with a non-limiting embodiment of the present invention. More specifically,FIG. 3depicted a front view thereof.

The tonnage regulating structure302comprises a body304. The body304is associated with a first height306—the first height306being height of the body304in a resting configuration or in other words, in a configuration when it is not in use, i.e. not positioned within a mold (not depicted) or positioned in the mold (not depicted) in a mold-open configuration.

The body304comprises a compensating structure308. In the particular embodiment depicted inFIG. 3, the compensating structure308comprises a plurality of cut-out portions310defined in the body304. In the specific example being depicted herein, there are three instances of the plurality of cut-out portions310. It is noted that the plurality of cut-out portions310are spaced along the height of the tonnage regulating structure302.

However, in alternative non-limiting embodiments of the present invention, other number of instances, other location and other form factor can be used. It is noted, however, that those skilled in the art will be able to select the location, form factor, number and depth of the plurality of cut-out portions310based on the following considerations. Enough material should be taken out by virtue of the plurality of cut-out portions310to enable the compensating effect (to be described herein below) to occur. At the same time, the remaining material of the body304should allow for the tonnage regulating structure302to perform the function of absorbing and/or re-distributing a portion of the clamp force “A”.

Generally speaking, the purpose of the compensating structure308is to control the first height306of the body304to a second height320, depicted inFIG. 4, under applied clamp tonnage “A” described herein above.FIG. 4depicts a tonnage regulating structure302′, which is actually the tonnage regulating structure302ofFIG. 3under applied clamp tonnage “A”. The tonnage regulating structure302′ similarly has a body304′ and the body304′ is associated with the second height320. The second height320is somewhat shorter than the first height306. Put another way, the second height320is the height of the body304′ in the “in-use” configuration or in other words when it is installed in the mold (not depicted) and the mold is in the mold-clamped configuration. In this particular example, this result is achieved due to the “spring like” or compression effect attributable to the compensating structure308. In other words, the compensating structure308affords a degree of resiliency to the body304that allows the body304to selectively change:

(a) from the first height306to the second height320when the mold (not depicted) is being closed and clamped; and

(b) from the second height320to the first height306when the mold (not depicted) is being opened.

This will be further illustrated with reference toFIG. 5.FIG. 5depicts an example of a mold502for use in a molding machine (not depicted, but well known to those of skill in the art). The mold502comprises a single molding cavity, but this needs not be so in every embodiment of the present invention and, as such, in alternative embodiments a multi-cavity mold may of course be used.

The mold502comprises a cavity portion504and a core portion506defining together therebetween a molding cavity508. The cavity portion504comprises a cavity side mold face510and the core portion506comprises a core side mold face512. The cavity side mold face510includes a cavity side parting line surface513and the core side mold face512includes a core side parting line surface511, these sometimes also being referred to by those of skill in the art as a “shadow face”.

Also provided inFIG. 5are two instances of the tonnage regulating structure302implemented in accordance with the embodiment depicted inFIG. 3andFIG. 4.FIG. 5depicts a configuration of the mold502where the closing of the cavity portion504and the core portion506has begun, but no clamp tonnage is yet being applied.

Within the illustration, the tonnage regulating structure302is associated with the first height306, as previously described. The mold502is associated with an opening clearance520—that is a distance between the cavity side mold face510and the core side mold face512. The opening clearance520is somewhat greater than a clearance between the cavity side mold face510and the core side mold face512in the mold closed and clamped configuration (not depicted inFIG. 5).

Reference will now be made toFIG. 6, which depicts a portion of the mold502ofFIG. 5in greater detail.FIG. 6shows a portion of the core portion506and a portion of the cavity portion504, as well as a portion of the tonnage regulating structure302. It is useful to recall now that the opening clearance520is somewhat greater than a clearance between the cavity side mold face510and the core side mold face512in the full mold closed and clamped configuration. This means and as is illustrated inFIG. 6, that in the position where the mold502is in the configuration where the closing of the cavity portion504and the core portion506has begun, but no clamp tonnage “A” is yet applied, a second gap “G2”, defined between the core side parting line surface511and the cavity side parting line surface513, is greater than a third gap “G3” defined between the tonnage regulating structure302and the core side mold face512.

As the clamp tonnage “A” is applied to the mold502, the second gap “G2” will eventually diminish to a point where the cavity side mold face510abuts the core side mold face512. At the same time, the compensating structure308will cause the tonnage regulating structure302to enter configuration depicted at302′ inFIG. 4(i.e. change from the first height306to the second height320).

To summarize, what the description ofFIG. 6demonstrates is:

(a) the tonnage regulating structure302has a resting height (in the “non-use” configuration) which is greater than the clearance between mold faces (ex. the first mold face103and second mold face105) in a mold closed and clamped configuration.

(b) the tonnage regulating structure302has an in-use height which is substantially the same as the clearance between mold faces (ex. the first mold face103and second mold face105) in a mold closed and clamped configuration.

Essentially, the compensating structure308allows the tonnage regulating structure302to toggle between these two configurations (i.e. two heights thereof), effectively compensating for any stack height differences and effectively, at least mitigating some of the problems discussed with reference to the prior art approaches. In other words, the compensating structure308allows for the body304to be selectively actuatable between the first height306in a resting configuration, the first height306selected to be larger than the opening clearance520, and the second height320in the in-use configuration, the second height320substantially corresponding to a clearance between mold faces (ex. the first mold face103and second mold face105) in a mold closed and clamped configuration.

To complete description of the structure of the tonnage regulating structure302, a brief reference is made toFIG. 13, which depicts a cross section of a portion of the mold502and shows the tonnage regulating structure302, a portion of the cavity portion504and a portion of the core portion506. The body304of the tonnage regulating structure302has defined, therethrough, an aperture1302. The aperture1302is configured, in cooperation with a complementary aperture1304defined in the core portion506, to accept a suitable fastener (not depicted) to couple the body304to the core portion506. In an alternative configuration (not depicted), the body304can be coupled to the cavity portion504and in those embodiments, the complementary aperture1304can be defined on the cavity portion504.

The net result enjoyable by use of the tonnage regulating structure302will be demonstrated with reference toFIG. 7AandFIG. 7B. More specifically,FIG. 7Aschematically depicts a first mold half702and a second mold half704and disposed therebetween a plurality of molding stacks706. The first mold half702is associated with a first mold face703and the second mold half704is associated with a second mold face705.

It is evident fromFIG. 7Athat some of the plurality of molding stacks706are dimensioned (length-wise) differently from others of the plurality of molding stacks706, these differences in dimensions being greatly exaggerated, for illustration purposes only, inFIG. 7A. For example, a first molding stack706ais longer than a second molding stack706b. By the same token, the second molding stack706bis longer than a third molding stack706c.

FIG. 7Afurther depicts two instances of a tonnage regulating structure708disposed between the first mold half702and the second mold half704, the two instances of the tonnage regulating structure708being implemented in accordance with the embodiment described above with reference toFIG. 3andFIG. 4.

FIG. 7Billustrates the net result of the function of the tonnage regulating structure708when at least a portion of clamp tonnage “A” is applied (in a manner known in the art, the clamp tonnage “A” can be generated by a suitable hydraulic clamp, electric clamp, toggle clamp or the like). Within the illustration, it can be clearly seen that a tonnage regulating structure708′ is in the “in-use” configuration, whereby the above-described compensating structure308has compensated for height differences between some of the plurality of molding stacks706. The net result is at least mitigation of some deformation of the first molding stack706a, the second molding stack706band the third molding stack706cand/or more even force distribution therebetween. A technical effect of embodiments of the present invention includes improved useful life span of the mold components (for example, the first molding stack706a, the second molding stack706band the third molding stack706cdue to at least partially to decreased wear on these components).

It should be noted that the embodiment of the compensating structure308described above is just one example of an implementation thereof. An alternative embodiment of the implementation is depicted inFIG. 8AandFIG. 8B.

FIG. 8Adepicts a tonnage regulating structure802implemented in accordance with another non-limiting embodiment of the present invention.FIG. 8Adepicts the tonnage regulating structure802in a resting configuration and it is associated with a first height806.FIG. 8Bdepicts a tonnage regulating structure802′, which is the tonnage regulating structure802under clamp tonnage “A”. The tonnage regulating structure802′ is associated with a second height806′. The tonnage regulating structure802is associated with a body804. The body804is made of a first material, such as steel and the like. The body804is associated with a compensating structure808, the compensating structure808being made of a second material which affords it a degree of resiliency. For example, the second material can be a resilient and/or deformable material, such as hot rubber, suitable plastic material and the like. Accordingly, under clamp tonnage “A” being applied, the compensating structure808(FIG. 8A) changes dimension height-wise to a compensating structure808′ (FIG. 8B), the process being reversed when the clamp tonnage “A” ceases to be applied. It is noted that it is this resiliency that allows to change the first height806to the second height806′.

FIG. 9AandFIG. 9Bdepict yet another embodiment of a compensating structure908(and a compensating structure908′ under clamp tonnage “A” being applied). The compensating structure908is substantially similar to the compensating structure808other than for the placement thereof. In the embodiment ofFIG. 9AandFIG. 9B, the compensating structure908is positioned in the middle of a body904. It is worthwhile noting that other placements for the compensating structure908are possible. It is also possible to place two or more instances (i.e. at least two instances) of the compensating structure906along the body904.

In yet further embodiments of the present invention, further implementations for the compensating structure308are possible. One such non-limiting embodiment is depicted with reference toFIG. 10.FIG. 10depicts a cross-sectional view of an example of a mold1001for use in a molding machine (not depicted, but well known to those of skill in the art). The mold1001comprises a single molding cavity, but this needs not be so in every embodiment of the present invention and, as such, in alternative embodiments a multi-cavity mold may of course be used.

The mold1001comprises a cavity portion1004and a core portion1006defining together therebetween a molding cavity1008. The cavity portion1004comprises a cavity side mold face1010and the core portion1006comprises a core side mold face1012. Also provided inFIG. 10are two instances of a tonnage regulating structure1002implemented in accordance with another non-limiting embodiment of the present invention.FIG. 10depicts a configuration of the mold1001where the closing of the cavity portion1004and the core portion1006has begun, but no clamp tonnage is yet being applied.

FIG. 10also illustrates a melt inlet1020for communicating molding material towards the molding cavity1008. Also shown inFIG. 10is a stripper assembly1022, which includes a stripper plate1024and an ejector1026. Operation of the stripper assembly1022is well-known to those of skill in the art and it is generally used to assist in ejecting a molded part (not depicted) off the core portion1006.

Within these embodiments of the present invention, the tonnage regulating structure1002comprises a body1040. The body1040is depicted in its resting configuration, as has been described herein above in respect to other non-limiting embodiments of the present invention. The body1040comprises a first portion1042and a second portion1044. The first portion1042is coupled to the core portion1006by means of a suitable fastener (not depicted) receivable within complementary bores1046A,1046B defined, respectively, in the core portion1006and the first portion1042. The second portion1044is coupled to the cavity portion1004by means of a suitable fastener (not depicted) receivable within complementary bores1048A,1048B defined, respectively, in the cavity portion1004and the second portion1044.

Within these embodiments of the present invention, the first portion1042can be implemented as a compensating structure. As such, within these embodiments, the second portion1044can be made of a first material, such as steel and the like and the first portion1042can be made of a second material which affords it a degree of resiliency. For example, the second material can be a resilient and/or deformable material, such as hot rubber, suitable plastic material and the like. Naturally, the construction of the first portion1042and the second portion1044can be reversed. In other words, it can be said that one of the first portion1042and the second portion1044can be implemented as the compensating structure.

Resiliency of the second material, within these embodiments of the present invention, allows for the body1040of the tonnage regulating structure1002to change from the first, resting, height to a second, in-use, height, as has been described herein above with reference to other non-limiting embodiments of the present invention, whereby the second height is smaller than the first height.

With brief reference toFIG. 11, another non-limiting implementation will be described.FIG. 11depicts a variant of the mold1001ofFIG. 10, which is implemented in substantially the same manner other than for the specific differences to be described momentarily. As such, specific components of the mold1001inFIG. 11, which are implemented in a similar manner to those ofFIG. 10, are not separately numbered and reference can be made back toFIG. 10for the description thereof.

What distinguishes illustration ofFIG. 11from that ofFIG. 10is how the first portion1042and the second portion1044are coupled. The second portion1044is coupled to the cavity portion1004by means of a suitable fastener (not depicted) receivable within complementary bores1048A,1048B defined in the cavity portion1004and the second portion1044, respectively. The first portion1042is coupled to the second portion1044by means of a suitable fastener (not depicted) receivable within complementary bores1050A,1050B defined, respectively, in the first portion1042and the second portion1044. Within these embodiments of the present invention, the first portion1042can implement the compensating structure.

It should be understood that yet further non-limiting implementations for the compensating structure are possible. For example, a resiliently-biased implementation is possible, where the compensating structure308is implemented as a resiliently-biased member (such as a spring and the like) urging the compensating structure308to the first height306.

An example of such non-limiting implementation will now be described in greater detail with reference toFIG. 12.FIG. 12depicts another non-limiting embodiment of the mold1001, which is implemented in a substantially similar manner to what has been described above with reference toFIG. 10, but for the specific differences to be described herein below.

The mold1001includes two instances of a tonnage regulating structure1202implemented in accordance with another non-limiting embodiment of the present invention.FIG. 12depicts a configuration of the mold1001where the closing of the cavity portion1004and the core portion1006has begun (but is not finished yet), but no clamp tonnage is yet being applied.

Within these embodiments the present invention, the tonnage regulating structure1202comprises a body1240. The body1240is depicted in its resting configuration, as has been described herein above in respect to other non-limiting embodiments of the present invention. The body1240comprises a first portion1242and a second portion1244. The second portion1244is coupled to the cavity portion1004by means of a suitable fastener (not depicted) receivable within complementary bores1048A,1048B defined, respectively, in the cavity portion1004and the second portion1244.

Within these embodiments of the present invention, the first portion1242can be implemented as a compensating portion. Within these embodiments of the present invention, the first portion1242comprises a spring pack1248positionable within a pocket1246defined in the core portion1006. The first portion1242further comprises a pin1250and a retainer1252. The retainer1252comprises an aperture (not separately numbered) and a portion of the pin1250is biased upwardly (as viewed inFIG. 12) through the aperture in the retainer1252, towards the cavity portion1004, by the spring pack1248, in a resting configuration. The retainer1252cooperates with a shoulder (not separately numbered) of the pin1250to retain the pin1250(and the spring pack1248) within the pocket1246. Naturally, the positioning of the first portion1242and the second portion1244can be reversed.

Within these embodiments, the spring pack1248allows for the pin1250to toggle between an extended arrangement (in the resting configuration), as is depicted inFIG. 12, and a compressed arrangement (in the in-use configuration). This, in turn, allows the body1240of the tonnage regulating structure1202to change from the first, resting, height to a second, in-use, height, as has been described herein above with reference to other non-limiting embodiments of the present invention, whereby the second height is smaller than the first height.

Within the illustration ofFIG. 12, as the cavity portion1004and the core portion1006continue to be urged together and eventually clamped, the spring pack1248will compress, the pin1250will retract, eventually coming to the second, in use, height. The process is reversed as the mold is unclamped and the cavity portion1004and the core portion1006are urged apart.

In yet another alternative non-limiting variation of the implementation of the embodiment ofFIG. 12, the second portion1244of the body1240can be omitted. Within that alternative, the body1240comprises the first portion1242and the pin1250is configured to act directly on a mold face (not separately numbered) of the cavity portion1004.

It is noted that the compensating structure implemented in accordance with various non-limiting embodiments described above allows for a controlled deformation of the compensating structure, as opposed to the uncontrolled deformation experienced in the prior art designs. In other words, by selecting the resting height and degree of resiliency of the compensating structure, it is possible to achieve a controlled deformation to the in-use height, which allows to enjoy the benefit of the tonnage regulating structure (i.e. absorption and/or re-distribution of the clamp tonnage “A”), while at least partially alleviating the need to manufacture the tonnage regulating structure to extremely high tolerances.

Description of the non-limiting embodiments of the present inventions provides examples of the present invention, and these examples do not limit the scope of the present invention. It is to be expressly understood that the scope of the present invention is limited by the claims. The concepts described above may be adapted for specific conditions and/or functions, and may be further extended to a variety of other applications that are within the scope of the present invention. Having thus described the non-limiting embodiments of the present invention, it will be apparent that modifications and enhancements are possible without departing from the concepts as described. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims: