INJECTION MOLDED PLASTIC STRUCTURE

FIELD OF THE INVENTION
[001] The present invention relates to plastic structure and, more particularly to injection molded plastic structure and injection molding process.
BACKGROUND
[002] Generally, to manufacture the plastic structure by injection molding, the molding material is introduced into the molding cavity at high temperature and low viscosity, by force of injection pressure, so as to flow and fill the mold cavity. Typically, the relative thickness versus elongation of an article to be injection molded using heated plastic resins or the like, can cause molding challenges and design constraints. If the molded part is thin, higher injection pressure is required to fill the mold quickly, and it causes other design and operational problems. Tradeoffs that are made such as high injection pressure or multiple gates, in molding very thin wall articles can affect the strength of the molded parts, their surface quality, cost, the speed at which they can be produced and other factors.
[003] Therefore, it would be advantageous to develop a way to produce injection molded thinner plastic/resin structure to save material and cost.
SUMMARY
[004] In an embodiment, an injection molded resin structure is provided. The injection molded resin structure includes a first side surface comprising a plurality of flat sectors and a plurality of protrusions. Each sector of the plurality of flat sectors is surrounded by one or more protrusions of the plurality of protrusions. The plurality of flat sectors and the plurality of protrusions are configured using an injection molding process. A thickness of each of the plurality of flat sectors is less than about 2.5 millimeters (mm). A second side surface of the injection molded resin structure includes a substantially flat structure configured using the injection molding process.
[005] In an embodiment, the injection molded resin structure is a side cover of the two-wheeled vehicle. In an embodiment, thickness of any of the plurality of protrusions is more than thickness of any of the plurality of flat sectors.
[006] In an embodiment, injection molding process includes injecting fluid resin through at least one resin injection port in one of a plurality of grooved open channels formed in a first mold member of an injection mold, where the plurality of grooved open channels are fluidically interconnected. Further, the plurality of flat sectors is formed from fluid resin dispersed from the plurality of grooved open channels. The injection molding process forms the plurality of protrusions from fluid resin collected in the plurality of grooved open channels. The injection molding process further includes forming the second side surface depending upon a shape of a second mold member of the injection mold, wherein the second mold member overlaps with the first mold member during the injection molding process.
[007] In another embodiment, an injection mold is provided. The injection mold includes at least one resin injection port, a first mold member and a second mold member. The first mold member forms a first side surface of an injection molded resin structure. The first mold member includes a plurality of spaced apart grooved open channels configured in a substantially flat surface of the first mold member. The plurality of grooved open channels are fluidically interconnected connected to each other and to the at least one resin injection port. When fluid resin is injected through the at least one resin injection port during an injection molding process, the fluid resin flows through all channels of the plurality of grooved open channels. The second mold member is adapted to overlap with the first mold member during the injection molding process for forming a second side surface of the injection molded resin structure. Fluid resin collected in the plurality of grooved open channels form a plurality of protrusions of the first side surface and fluid resin dispersed from the plurality of grooved open channels form a plurality of flat sectors of the first side surface.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[008] The invention itself, together with further features and attended advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only wherein like reference numerals represent like elements and in which:
[009] Figure 1 illustrates a schematic side view of a two-wheeled vehicle in accordance with an embodiment of the present invention;
[0010] Figure 2 illustrates a view of an injection molded resin structure, according to an embodiment of the present invention;
[0011] Figure 3 illustrates another view of the injection molded resin structure, according to an embodiment of the present invention;
[0012] Figure 4 illustrates a sectional view of the side cover illustrated in Figure 3 along the line AA’, according to an embodiment of the present invention;
[0013] Figure 5 illustrates a view of an injection mold, according to an embodiment of the present invention; and
[0014] Figure 6 illustrates another view of the injection mold, according to an embodiment of the present invention.
[0015] The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature. The coloured drawings, if provided along with this description are only meant to make the details of invention clear and have no effect whatsoever on the scope of the invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS AND PREFERRED EMBODIMENT
[0016] While the invention is susceptible to various modifications and alternative forms, an embodiment thereof has been shown by way of example in the drawings and will be described here below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention.
[0017] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0018] For the better understanding of this invention, reference would now be made to the embodiment illustrated in the accompanying figures and description here below, further, in the following figures, the same reference numerals are used to identify the same components in various views.
[0019] The terms “front / forward”, “rear / rearward / back / backward”, “up / upper / upward”, “down / downward / lower / lowerward” that may be used therein represent the directions as seen from a vehicle driver sitting astride and these directions are referred by arrows Fr, Rr, U, Lr in the drawing figures. Further, “left / leftward”, “right / rightward” that may be used herein represent the directions as seen from a vehicle driver sitting astride.
[0020] The terms “injection molded resin structure” and “resin structure” have been interchangeably used throughout the description. Further, the terms “resin” or “plastic” have been interchangeably used throughout the description.
[0021] Figure 1 illustrates a side view of a two-wheeled vehicle (100) according to an embodiment of the present invention. The two-wheeled vehicle (100) comprises, inter-alia, a front fork (121), a head pipe (122), a front fender (133), a front wheel (123), a headlight (132), a steering handle bar (124), a fuel tank (125) an engine unit (126), a side cover (113), at least one rear suspension (129), a side stand (119), a swing arm (173), a dress guard (111), a rear wheel (127), a rear fender (116), a tail light (117), and a seat (130). It may be noted that the vehicle (100) is shown to have include above stated parts, however, those skilled in the art would appreciate that the vehicle (100) includes other parts which may not be relevant for explaining the present invention and hence are not shown and described.
[0022] With reference to Figure 1, the front fork (121) is steerably supported by the head pipe (122) enabling free steering and extends in a downward direction from the head pipe (122). Lower end of the front fork (121) is supporting the front wheel (123) and the steering handle bar (124) is attached to an upper end of the front fork (121). A left and right seat rail members (not visible in the figures) are primarily intended to support a seat (130) (rider and / or pillion) disposed above the rear wheel (127). The dress guard (111), which is connected to the left seat rail member (not shown), and pillion step member (112) cover left side of the rear wheel (127). The rear wheel (127) is covered from above by the rear fender (116) which is mounted to a rear end portion of the left seat rail member and right seat rail member (not shown). A rear wheel suspension section includes the swing arm (173) supporting the rear wheel (127) and the at least one rear suspension (129) attached between the swing arm (173) and the left or right seat rail members. The tail light (117) is mounted on the rear fender (116).
[0023] With reference to Figure 1, a body frame of the two-wheeled vehicle (100) comprises of a main frame which extends obliquely in a rearward and downward direction from the head pipe (122), the pair of left and right seat rail members extending from a rear end portion of the main frame; a pair of a left down frame member (102) and a right down frame member (the right down frame member is not visible and overlapping with the left down frame member (102)) extending in the downward and then rearward direction from a front end portion of the main frame; a pair of left centre frame member (not shown) and a right centre frame member (not shown) connected to rear end portions of respective left down frame member (102) and the right down frame member in a state that left and right centre frame members are extended obliquely in a downward and rearward direction from a rear portion of the main frame and thereafter, in the downward direction, and a pair of left sub frame member (not shown) and a right sub frame member (not shown) which are respectively extended between left seat rail member and left centre frame member and between the right seat rail member and the right centre frame member, respectively.
[0024] With reference to Figure 1, the engine unit (126) is provided with a crankcase that houses a crankshaft, a cylinder body is provided to the front of crankcase and a cylinder head provided to the cylinder body and the engine unit (126) is located under the main frame. The engine unit (126) is placed below the main frame. An exhaust pipe extends from the engine unit (126) and a muffler is connected to a rear end of the exhaust pipe. Air to the engine unit (126) is supplied by an air cleaner assembly (not shown) which is arranged in a space surrounded by the pair of seat rail members; the left and right centre frame members; and the left and right sub frame members.
[0025] One or more body covers is/are mounted to cover the body frame of the vehicle (100), typically, body covers are used to enhance the aesthetic appeal of the vehicle (100). For example, as illustrated in Figure 1, a side cover (see, 113) that is made of an injection molded resin structure is mounted to the fuel tank (125) and the body frame to cover a side portion of the body frame. Similarly, a rear side cowl (113a) is mounted to the towards rear side of the body frame to cover the left and right seat rails of the vehicle (100). Generally, these body covers are made up of resin, preferably, injection molded resin structure.
[0026] Figures 2 and 3 illustrate different views of the injection molded resin structure (113), according to an embodiment of the present invention. In an embodiment, the injection molded resin structure (113) is used as the side cover of the vehicle (100), and hence the injection molded resin structure (113) is also interchangeably referred to as the side cover (113). The injection molded resin structure (113) is formed using an injection mold (200) in an injection molding process. Figures 5 and 6 illustrate different views of the injection mold (200), according to an embodiment of the present invention.
[0027] One or more embodiments of the injection molded resin structure (113) and its formation using the injection mold (200) is described herein below by jointly referring to Figures 2 to 6.
[0028] In Figure 2, the side cover (113) which is an injection molded resin/plastic structure, is illustrated. The present invention is described by taking the side cover (see, 113) as an example of injection molded resin structure (113). However, the present invention is not limited to the side cover (113) and it is applicable for any other resin covers/parts that can be used in vehicles such as the vehicle (100). The injection molded resin structure (113) includes two surfaces as side surface ‘A’ (see, a second side surface (15)) and side surface ‘B’ (see, a first side surface (10)). As shown in Figure 2, the second side surface (15) forms the outer surface of the vehicle (100) when it is mounted to the body frame of the vehicle (100). As shown in Figure 3, the first side surface (10) of the resin structure (113) is a patterned surface which is not visible from outside when the resin structure (113) is mounted to the body frame of the vehicle (100).
[0029] As shown in Figure 3, on the first side surface (10) of the injection molded resin structure (113), a plurality of protrusions and a plurality of sectors are visible. In the illustrated Figure 3, the first side surface (10) has a patterned surface having a plurality of small sectors (3a, 3b, 3c, 3d, 3e, 3f, 3h, 3k, 3L, 3m, 3o) and a plurality of protrusions (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2L, 2m). For the sake of explanation, the plurality of sectors (3a, 3b, 3c, 3d, 3e, 3f, 3h, 3k, 3L, 3m, 3o) are commonly referred by reference numeral 3 and are represented as 'plurality of sectors (3)'. Similarly, the plurality of protrusions (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2L, 2m) is commonly referred by reference numerals ‘2’ and is represented as 'plurality of protrusions (2)'. Each sector of the plurality of sectors (3) is surrounded by one or more of the plurality of protrusions (2). For example, the sector ‘3b’ is surrounded by four protrusions (2d, 2e, 2f, 2g).
[0030] The injection molded resin structure (113) is formed using the injection mold (200) as shown in Figures 5 and 6. Figure 5 represents a first mold member (210) for forming the first side surface (10) of the injection molded resin structure (113), and Figure 6 represents a second mold member (215) for forming the second side surface (15) of the injection molded resin structure (113). It is to be understood that the injection mold (200) is a part of an equipment (not shown) that performs the injection molding process to produce the resin structure (113), where the injection mold (200) includes a base portion (e.g., the second mold member (215)) for forming the second side surface (15) and an opposing portion (e.g., the first mold member (210)) for forming first side surface (10).
[0031] The first mold member (210) and the second mold member (215) may be fitted together (e.g., in overlapping configuration) to form the first side surface (10) and the second side surface (15) in the injection molding process. For instance, the mold members (210) and (215), together produce a substantially flat resin structure (113) formed with better and more complete filling of the molding with the melted material. The more complete filling of the molding is accomplished by a flow pattern as decided by a plurality of spaced apart interconnected grooved open channels in the injection mold (200) which allow the melted resin to flow easily. As shown in Figures 5 and 6, the injection mold (200) includes at least one resin injection port (212) in form of an orifice, through which fluid resin can be injected in the injection mold (200). The fluid resin is merely an example, and any other liquid for example melted plastic can also be injected through the resin injection port (212) during the injection molding process. As shown in Figure 5, the injection mold (200) includes a pair of first mold members (210) for forming first side surface (10) of a pair of resin structures (113) (e.g., for being used as right and left side covers of the vehicle (100)), however only one of the pair of first mold members (210) is explained herein for the sake of simplicity.
[0032] The first mold member (210) includes a plurality of surface sections (53a, 53b, 53c, 53d, 53e, 53f, 53h, 53k, 53L, 53m, 53o) and a plurality of spaced apart grooved open channels (52a, 52b, 52c, 52d, 52e, 52f, 52g, 52h, 52i, 52j, 52k, 52L, 52m) formed in a mess configuration on a substantially flat surface (220) of the first mold member (210). For the sake of explanation, the plurality of surface sections (53a, 53b, 53c, 53d, 53e, 53f, 53h, 53k, 53L, 53m, 53o) are commonly referred by reference numeral 53 and are represented as 'plurality of sections (53)'. Similarly, the plurality of grooved open channels (52a, 52b, 52c, 52d, 52e, 52f, 52g, 52h, 52i, 52j, 52k, 52L, 52m) are commonly referred by reference numerals ‘52’ and arae represented as 'plurality of open channels (52)'.
[0033] The plurality of open channels (52) extend from the at least one resin injection port (212), such that all of the plurality of open channels (52) are fluidically interconnected during the injection molding process and are also fluidically connected to the plurality of surface sections (53) of the first mold member (210). As illustrated in example embodiment of Figure 5, the plurality of open channels (52) are arranged in interlinked square/rectangular pattern so that during the molding process, the melted resin flows from the injection port (212) to one or more open channels (52) and reaches to all of the plurality of open channels (52). It should be noted that the plurality of open channels (52) may be fluidically interlinked in various other configurations (e.g., concentric, triangular, etc.) such that fluid resin introduced to any one channel (52) can reach easily to all of the other open channels (52). Each of the plurality of sections (53) is surrounded by one or more open channels (52). For example, the section ‘53b’ is surrounded by four open channels (52d, 52e, 52f, 52g). Accordingly, the section ‘53b’ can be filled by the melted resin primarily flowing from the four open channels (52d, 52e, 52f, 52g) to form the sector '3b' (see, Figure 3) of the resin structure (113). It should be appreciated that the plurality of open channels (52) allow the melted resin injected from the at least one injection port (212) to reach the plurality of sections (53) and form the plurality of sectors (3) without any resistance thereby obtaining a plurality of thin flat sectors (3) in the resin structure (113).
[0034] The pluralities of protrusions (2) are thickest sections/portions of the resin structure (113) as compared to thickness of the sectors (3). Figure 4 illustrates a section view of the injection molded resin structure (113) as illustrated in Figure 3 along the line AA’, according to an embodiment of the present invention. In an embodiment, the first side surface (10) includes the plurality of protrusions (2) having thickness ‘x’ and the thickness of the sectors (3) is ‘y’. The thickness ‘y’ is smaller than the thickness ‘x’ of the protrusions (2). In an embodiment, the thickness of each of the plurality of protrusions (2) varies, and the thickness ‘y’ of the sectors (3) is less than the smallest thickness of a protrusion (2) among all of the plurality of protrusions (2). In an embodiment, a thickness of each of the plurality of flat sectors (3) is less than about 2.5 millimetres (mm).
[0035] As the melted resin is introduced into the injection mold (200) through the injection port (212), the melted resin fills the plurality of open channels (52) in the injection mold (200). The open channels (52) may be of various sizes depending upon a level of flow of melted resin intended in the corresponding portion of the article. The plurality of open channels (52) allow the melted resin injected from the at least one orifice to reach the plurality of sections (53) locations to form the corresponding sectors (3) without any resistance thereby obtaining a plurality of thin sectors (3) in the finished product i.e. the resin structure (113).
[0036] As described in the aforementioned description, the design of the resin structure (113) enables to save material by forming the sectors (3) having comparatively less thickness than the plurality of protrusions (2) thereby saving the material cost. In other words, the material is saved from the surface of the sectors (3) by reducing the thickness of the surface which otherwise would have been same as the thickness of the protrusions (2).
[0037] Further, the plurality of open channels (52) having sufficient depth allows the melted resin to flow therein to form the resin structure (113) without the need to increase the injection pressure or the number of orifice (e.g., the injection port (212)) for introducing the melted resin.
[0038] Furthermore, the plurality of protrusions (2) also provides sufficient strength to the resin structure (113). Also, as the plurality of protrusions (2) are provided on the first side surface (10) of the resin structure (113) which is generally not visible from the outside, therefore, there is no deterioration in the aesthetic look of the vehicle (100) when the resin structure (113) is mounted to vehicle (100).
[0039] While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. For example, the support stay can be mounted on the right seat frame or any other suitable portion of the body frame. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

CLAIMS
We claim:
1. An injection molded resin structure (113), comprising:
a first side surface (10) comprising a plurality of flat sectors (3) and a plurality of protrusions (2), each sector of the plurality of flat sectors (3) surrounded by one or more protrusions of the plurality of protrusions (2), wherein the plurality of flat sectors (3) and the plurality of protrusions (2) are formed using an injection molding process, wherein thickness of each of the plurality of flat sectors (3) is less than about 2.5 millimetres (mm).
2. The injection molded resin structure (113) as claimed in claim 1, further comprising a second side surface (15) comprising a substantially flat structure configured using the injection molding process.
3. The injection molded resin structure (113) as claimed in claim 1, wherein the injection molded resin structure (113) is a side cover of the two-wheeled vehicle (100).
4. The injection molded resin structure (113) as claimed in claim 1, wherein thickness of the plurality of protrusions (2) is more than thickness of the plurality of flat sectors (3).
5. The injection molded resin structure (113) as claimed in claim 2, wherein the injection molding process comprises:
injecting fluid resin through at least one resin injection port (212) in one of a plurality of grooved open channels (52) formed in a first mold member (210) of an injection mold (200), wherein the plurality of grooved open channels (52) are fluidically interconnected;
forming the plurality of flat sectors (3) from fluid resin dispersed from the plurality of grooved open channels (52); and
forming the plurality of protrusions (2) from fluid resin collected in the plurality of grooved open channels (52).
6. The injection molded resin structure (113) as claimed in claim 5, wherein the injection molding process further comprises forming the second side surface (15) based on a shape of a second mold member (215) of the injection mold (200), wherein the second mold member (215) overlaps with the first mold member (210) during the injection molding process.
7. An injection mold (200), comprising:
at least one resin injection port (212);
a first mold member (210) for forming a first side surface (10) of an injection molded resin structure (113), the first mold member (210) comprising
a plurality of spaced apart grooved open channels (52) configured in a substantially flat surface (220) of the first mold member (210), wherein the plurality of grooved open channels (52) are fluidically interconnected to each other and to the at least one resin injection port (212), wherein when fluid resin is injected through the at least one resin injection port (212) during an injection molding process, the fluid resin flows through all channels of the plurality of grooved open channels (52); and
a second mold member (215) adapted to overlap with the first mold member (210) during the injection molding process for forming a second side surface (15) of the injection molded resin structure (113),
wherein fluid resin collected in the plurality of grooved open channels (52) form a plurality of protrusions (2) of the first side surface (10) and fluid resin dispersed from the plurality of grooved open channels (52) form a plurality of flat sectors (3) of the first side surface (10).
8. The injection mold (200) as claimed in claim 7, wherein a thickness of the plurality of protrusions (2) is greater than a thickness of the plurality of flat sectors (3) of the injection molded resin structure (113).
9. The injection mold (200) as claimed in claim 7, wherein one or more grooved open channels of the plurality of grooved open channels (52) have different depths.
10. The injection mold (200) as claimed in claim 7, wherein the plurality of grooved open channels (52) are configured in a mesh configuration such that during the injection molding process, each sector of the plurality of flat sectors (3) is formed at least by dispersed fluid resin from one or more surrounding grooved open channels (52).
11. The injection mold (200) as claimed in claim 7, wherein the second mold member (215) has a substantially flat structure.
12. The injection mold (200) as claimed in claims 7 or 10, wherein thickness of each of the plurality of flat sectors (3) is less than about 2.5 millimetres (mm).