screw boss

Abstract

The invention relates to a screw boss. The screw boss (10) comprises a base (11) and an upstanding body (12) having an opening (14) at one end thereof. A series of ribs (13) are spaced around the body (12), each rib being located approximately coincident with an imaginary tangent (G) extending from the edge of the opening (14). In this way, the torque applied by a fastener driven into the opening is optimally absorbed by the rib locations, such that a faster cycle time for screwing components into place can be achieved.

Description

Technical Field

[0001] This disclosure relates to a screw boss, specifically a boss for a self-tapping screw, characterized by a guide hole into which the self-tapping screw can be screwed to hold the component in place. Background Technology

[0002] Screw bosses are a common solution for ensuring the correct positioning of metal self-tapping screws into plastic holes. A typical example of a screw boss (alternatively called a screw post or shank) comprises a cylindrical body made of deformable plastic material with a hole (e.g., a blind hole) formed at its central axis to receive the self-tapping screw. The body is formed to stand upright from and be integral with the support surface / base, and may include two or more ribs radiating from the central axis, which provide additional stability by mitigating lateral movement as the screw rotates into the hole and absorbing torsional forces exerted on the body relative to its support surface.

[0003] In use, one or more individual parts can be secured by their own through holes and self-tapping screws of compatible hole size, the through holes being aligned with the through holes of the screw boss, the self-tapping screws being introduced into the boss through the part. Using a harder material (e.g., metal), the threads bite into and are pulled into the plastic inner wall of the hole. The hole may have surface features for guiding the screw (e.g., bevels / internal ribs) or be relatively smooth, but it is always deeper than the length of the screw so that it fully accommodates the screw shaft up to the screw head when the part is in place. The deformable walls of the hole / body can expand at the edges to accommodate the screw, further reinforced by radial ribs.

[0004] Screw bosses are used to separate the surface of a component by their body height and securely mount the component in place, typically for the duration of the assembled product's lifespan. However, self-tapping screws can be removed by turning them in the opposite direction of the thread and thereby pulling them out of the hole. Therefore, parts of the product can be disassembled if necessary.

[0005] When a self-tapping screw engages, the screw boss is subjected to torque. Therefore, the design of the screw boss must take into account its ability to withstand these forces and resist the materials used in the manufacture of the component (e.g., plastics, alloys, aluminum). In particular, the relative elasticity of the screw boss to torque will affect the speed at which the screw can be screwed into its hole, thereby affecting the total cycle time for assembling a component / product, which may have multiple screw bosses integrated therewith. Ribs are provided as a support structure and also provide enhanced strength to the boss and the ability to expand the boss to accommodate the screw. It is known to those skilled in the art that a screw boss may fail if excessive torque is applied, for example, due to high-speed tightening. Summary of the Invention

[0006] Based on the above, the present invention seeks to address the drawbacks associated with known screw boss structures and proposes an improvement, particularly a solution, that can reduce screw cycle time / increase screw rotation speed or reduce the material used in the manufacturing process.

[0007] A first aspect of the invention is summarized. For example, a screw boss may include: a base; a body erected from the base, having an outer sidewall and an opening for securing a threaded element into the opening; and a plurality of ribs, each rib spanning between / adjacent to the base and the body; wherein at least one of the plurality of ribs extends from a position on the outer sidewall that is parallel to but angularly offset from a normal radial line truncated from the center of the opening. The offset may be at least half the thickness of the rib from the radial line. At the point where the rib connects to the sidewall of the boss, the rib is preferably positioned to extend parallel to the radial line, offset toward a parallel tangent to the opening for securing the screw (including coinciding with or exceeding the parallel tangent), so as to offset from the normal radial line parallel to it.

[0008] Thus, the screw boss of the present invention has the following effect: it provides an alternative rib position to better accommodate the torque generated by the self-tapping screw, and therefore can potentially increase the tightening speed. Therefore, the problem of slow cycle time during screwing into plastic is solved, for example, by offsetting the position of the rib attached to the body to one side of an imaginary radial line intercepted from the center of the hole / bore, specifically the position of the force distributed during self-tapping.

[0009] Due to the novel structure disclosed here, the ribs are positioned for optimal force distribution to ensure proper implementation of the screwing process. The boss body, while reinforced by the ribs, retains the freedom to expand, resulting in reduced cycle time and / or a decreased chance of boss breakage / failure.

[0010] In conventional designs, support ribs are arranged radially in a uniform, intersecting pattern from the center of the screw hole. In contrast, the ribs of this invention deviate from their normal radial position, cut off from the center of the fixed opening. This deviation can be counterclockwise or clockwise. In one form, the ribs deviating from the normal radial line are counterclockwise to address the most common clockwise screw orientation. However, for the intended left-hand screw orientation, the configuration is reversed to a clockwise deviation.

[0011] Preferably, the entire thickness of the rib extends outside the radial line starting from the center, but at least begins parallel to that radial line. The thickness of the rib can be approximately equal to the diameter of the opening, but any suitable size can be considered.

[0012] Each rib typically has the same shape as the other ribs, but different rib structures / shapes are possible.

[0013] Furthermore, the ribs can be constructed to taper outwardly from the connection point on the side wall of the body away from the base. In other words, the rib is wider at the connection point at the base than at the connection point further upward on the body. The taper of the rib can be either in the longitudinal direction of the upright body or in the radial direction from the body, or both. In the case of radial taper or draft angle designs, the reinforcement at the upper part of the boss is minimized compared to that at the base to reduce resistance to screw forces, where the upright body must be supported to prevent lateral breakage during the completion of the screw cycle and throughout the life of the assembled product. The torque is greatest at the end of the cycle, at which point the screw head abuts the body and is prevented from further penetrating the hole.

[0014] The height of the main body can be determined by assembly parameters, particularly by the length of the screw to be inserted / fixed into the hole. Taking into account the thickness of the part being fixed to the boss, the depth of the receiving hole preferably exceeds the total penetration length of the screw shaft.

[0015] In practice, screw bosses are formed as a single piece, with the base, body, and rib integrally formed and made from a continuous material component, such as by injection molding; however, co-molding or other manufacturing methods are also possible. Screw bosses can be formed from plastics, metals (e.g., aluminum), or other flowable / moldable materials.

[0016] The screw bosses can be aligned for mounting and securing various components or sandwich structures of multiple components, such as a single PCB or a PCB with a cover plate, which is screwed onto a base component having an upright screw boss according to the invention.

[0017] Preferably, the upright leading edge of the outer surface of the rib (at which the rib connects to the sidewall) extends at approximately 45 degrees from an imaginary line orthogonal to the sidewall to optimally provide support against the torque exerted by the rotating screw during assembly and to support the final torque required to hold the component in place. As mentioned above, this configuration can accommodate faster screwing speeds at the start and during screwing cycles for the same material as conventional radial ribs.

[0018] In an alternative expression of the invention, the plane of the rib (e.g., the center plane) is approximately tangent to the edge of the opening of the receiving screw, or between the tangent of the opening and the tangent of the body. In other words, at least a portion of the thickness of the rib at the location where it connects to the sidewall of the boss is tangent to the opening or overlaps with the tangent of the opening. Thus, the force generated at the wall of the opening where the thread contacts the wall and applies force is uniformly transmitted to the rib.

[0019] In summary, the present invention is implemented by a screw boss comprising: a base; a body; an opening at an end of the body remote from the base for securing a threaded fastener into the opening; and at least one rib adjacent to the base and the body to support the body in an upright position; wherein the at least one rib extends from the body at a position tangent to the opening. The rib position should be interpreted as any position between the tangent of the opening and the tangent of the body.

[0020] Preferably, the tangents coincide within the thickness of at least one rib. In one form, the at least one rib is parallel to a radial line extending from the center of the opening and deviates laterally from the radial line.

[0021] Preferably, the at least one rib tapers inwardly from the base toward the body in the longitudinal direction. Alternatively or additionally, the at least one rib may extend outward from the body at a demolding angle.

[0022] Preferably, the at least one rib may include a plurality of ribs, each located in a position aligned with the tangent to the opening. Each of the plurality of ribs may radiate around the body at uniform intervals.

[0023] Preferably, the screw boss is configured for right-hand threaded fasteners, wherein the at least one rib is offset from the radial line in a counterclockwise direction.

[0024] Preferably, the at least one rib is offset far enough to avoid overlapping with the radial line.

[0025] The invention extends to a component that includes a screw boss with any desired features as described herein, for example, a component configured for use in the assembly of a vehicle.

[0026] The invention also extends to a method for mounting a first part to a base part, such as in a vehicle.

[0027] Preferably, four ribs are used; however, one rib may suffice, especially if the boss body is located at a corner of the component. Depending on space constraints and the size of the boss, two, three, or five or more ribs are also suitable.

[0028] In an alternative form of the invention, a screw boss is provided, wherein each of the plurality of ribs is parallel to but offset from a direct radial line taken from the center of the screw boss.

[0029] This invention can be applied not only to self-tapping screws but also to threaded components such as bolts. In these cases, the corresponding threads can be tapped / molded into the receiving hole. Torque is still generated in this arrangement, especially at the end of the cycle, at which point the fastener can be set to the desired torque to hold the component in place. Attached Figure Description

[0030] Illustrative embodiments will now be described with reference to the accompanying drawings, in which:

[0031] Figure 1 A series of views are shown for a first embodiment of the screw boss according to the present invention;

[0032] Figure 2 A series of views are shown for a second embodiment of the screw boss according to the present invention;

[0033] Figure 3 Plan views illustrating screw bosses of different sizes are shown;

[0034] Figure 4 Another plan view is shown, illustrating screw bosses of different sizes and force directions;

[0035] Figure 5 An overview of a third embodiment of the screw boss is shown;

[0036] Figure 6 A plan view of a fourth embodiment of the screw boss is shown;

[0037] Figure 7 A cross-sectional view of a screw fastener and screw boss in place is shown, the screw fastener being used to hold product components together; and

[0038] Figure 8 A front view of a product component having the screw boss of the present invention is shown. Detailed Implementation

[0039] The following description presents exemplary embodiments, and is consistent with the appendix. Figure 1This description is intended to explain the principles of the invention. However, the scope of the invention is not intended to be limited to the precise details of the embodiments or to exact conformity with all features and / or method steps, as variations will be apparent to those skilled in the art and are considered to be covered by the specification. The terminology used herein should be given a broad interpretation, which also includes equivalent functions and features. In some cases, several alternative terms (synonyms) have been provided for structural features, but these terms are not intended to be exhaustive. Descriptive terms should also be given the broadest interpretation; for example, the term "comprising" as used herein means "consisting of at least partially," thus interpreting each statement in this specification that includes the term "comprising" as may also include features other than those beginning with that term. Related terms such as "comprising" are interpreted in the same manner. Orientational terms such as "vertical," "horizontal," "upper," "lower," "lateral," "above," and "below" are used for ease of explanation, generally referring to the orientation shown in the illustrations, and are not intended to be ultimately limiting if equivalent functionality can be achieved with alternative dimensions and / or orientations. In practice, under current circumstances, terms such as "horizontal" axis or "vertical" axis may be influenced by the orientation applied to the screw boss structure. Therefore, all directional terms are relative to each other.

[0040] The description herein relates to embodiments having specific combinations of steps or features; however, it is envisioned that further combinations and cross-combinations of compatible steps or features between embodiments will be possible. In fact, isolated features can function as the invention independently of other features and do not necessarily need to be implemented as a complete combination.

[0041] It should be understood that the illustrated embodiments are for illustrative purposes only. In practice, the invention can be applied to many different configurations, wherein the embodiments will be readily apparent to those skilled in the art.

[0042] Figure 1 A series of views of the screw boss 10 according to the invention are shown from different perspectives. The screw boss 10 generally includes a base 11 (which is actually part of a larger part than the part shown), an upright body 12, and a plurality of ribs 13.

[0043] In the form shown, the body 12 is generally cylindrical, although it can have other elongated forms, and has a central opening 14 for receiving screw fasteners. In the example shown, the opening has a sloping edge or annular insert, but in other examples it has a smooth wall extending down to a specified depth (e.g., see...). Figure 7 (Example). In principle, the opening can extend all the way through the body 12 and the base 11, but it is more likely to be a blind hole that leaves open space at least beyond the distal end of the screw.

[0044] As in Figures 1 to 4 As best seen in the plan view, each rib 13 extends away from the sidewall of the body 12 at a position parallel to but offset from the radial line (R) intercepted from the central axis (X) of the opening / body. In this way, the ribs extending from opposite sides of the body 12 are misaligned and appear offset from each other. However, in the form shown with four ribs, the offset between adjacent ribs remains 90°, as is the case for a regular intersecting structure, as... Figure 4 As shown. The ribs shown have uniform spacing.

[0045] refer to Figure 3 and Figure 4 The desired position of the rib according to the invention can be described in several ways. First, the central plane P of the rib 13 is shown as parallel to and deviating from the radial line R, for example, deviating from more than half the thickness of the rib 13. Second, the central plane P of the rib 13 is substantially tangent to the wall of the opening 14, at which a screw fastener will contact the body 12 of the boss and apply force, for example in a clockwise direction, assuming a common right-hand thread. Figure 4 The diagram shows the directional force line F generated by the torsional force T caused by the rotation of the screw fastener. Third, the upright leading edge of the outer surface of the rib (at which the rib connects to the sidewall 12) originates at approximately 40 to 70 degrees from the central axis X of the hole. In all interpretations, the rib 13 is optimally positioned to resist the torsional force F exerted by the rotating screw during assembly and to provide support for applying the final torque to hold the component in place.

[0046] Typically, it is obvious that rib 13 is offset to one side of the radial line R and does not overlap with the radial line R. Alternatively or additionally, at the point where rib 13 connects to the body 12, it extends from the tangent of opening 14 and overlaps with the tangent of opening 14. Any portion of the thickness of rib 13 may coincide with the tangent of the hole / opening 14. Figure 4 The central plane P coincides with the tangent G.

[0047] Figure 1 One embodiment has four ribs 13 in the form of right-angled triangular wedges, wherein the right-angled corners are located at the junction between the base 11 and the upright body 12. The thickness is uniform, although alternative structures are also possible.

[0048] Figure 2 An alternative embodiment of the screw boss 10 is shown, wherein the rib 13 is configured to widen at a draft angle from the body 12 toward the base 11 (where the rib is thickest). In practice, in some embodiments, the body 12 may independently widen from the open end 14 toward the base 11. A draft angle of the type shown can facilitate removal from the injection molding die without significantly affecting its strength to accommodate torque. Figure 2As shown in the plan view, the position of rib 13 is similar in other respects. Figure 1 , Figure 3 and Figure 4 Location arrangement.

[0049] Figure 5 Show Figure 1 A variation of the embodiment in which the effective upright height of the body 12 is reduced. However, the function and position of the rib 13 remain the same. Any embodiment of the screw boss may have a height suitable for the screw length required to fasten the component or to provide clearance or surface features on the component.

[0050] Figure 6 A variation is shown in which the substantial outer surface of rib 13 is located approximately in line with the tangent G of the opening and the radial line R from the central axis X, respectively. As previously described, rib 13 is typically offset from and parallel to the radial line R, but now its thickness is approximately equal to the radius of the opening 14 (i.e., half its diameter). This illustrates the optimal position of the rib, which uses less material but is best positioned to absorb torque from the screw. It is noteworthy that, for all embodiments, the rib begins to extend from a position in line with the tangent of the opening (i.e., any portion of its thickness overlaps with the tangent of the opening or at least its outer surface is in line with the tangent of the opening), but the end of the rib away from its connection to the body may deviate from a straight line. The rib may be curved as long as it begins in a tangential position.

[0051] Figure 7 A cross-sectional view of the assembled product / component is shown, in which a threaded fastener (e.g., a self-tapping screw) with a threaded shaft 15 and a head 16 has been driven into a blind hole 14 of the boss body 12. The head 16 is typically engaged by a tool with a predetermined torque, wherein the shaft 15 passes through aligned openings of one or more component flanges 17 and 18. Clearly, the flange layer 17 (e.g., a PCB) is mounted to contact the screw boss 12 in order to isolate electrical components on the surface of the flange layer from undesirable contact with the base (not shown) or cover component 18 of the boss.

[0052] Although Figure 7 It is not easily seen, but the outwardly extending ribs of the present invention are arranged to accommodate torque when the shaft 15 engages and is driven into the hole 14 and at the end of the screw cycle, at which point the head 16 contacts the fixed component (17, 18).

[0053] Figure 8 A plan view of a base component 11 including the boss 12 and rib structure 13 as described above is shown. The rib 13 can be combined with other reinforcing ribs of the base 11. When the boss 12 is located in a corner of the component, the upright sidewalls extending from the base 11 can provide a supporting function, wherein, according to the invention, the size and number of supporting ribs vary.

[0054] Considering the aforementioned issues, the improved rib structure is designed to reduce the force applied during the drive of the screw into the boss. The cycle time during the tightening process can be reduced. Assuming a similar amount of material is used to construct the boss 12, the heat generated during tightening is expected to remain the same, or slightly higher due to the faster tightening.

[0055] In summary, the present invention is generally embodied as a screw boss comprising a base and an upright body having an opening at one end. A series of ribs are spaced apart around the body, each rib being located off-center from its normal radial position, i.e., substantially coinciding with (towards, at, or beyond) an imaginary tangent extending from the edge of the opening. In this manner, the torque applied by the fastener driven into the opening is optimally absorbed by the rib positions, enabling faster cycle times for screwing the component into place.

Claims

1. A screw boss (10), the screw boss comprising: Base (11); Main body (12); An opening (14) is provided at one end of the body (12) away from the base (11) for securing a threaded fastener (15) into the opening; as well as At least one rib (13) adjacent to the base (11) and the body (12) to support the body (12) in an upright position; The at least one rib (13) extends from the body (12) at an off-center position that coincides with the tangent (G) of the opening (14) and toward a radial line (R) that is parallel to the tangent (G) and starts from the central axis (X) of the opening.

2. The screw boss according to claim 1, wherein, The tangent (G) coincides within the thickness of at least one rib (13).

3. The screw boss according to claim 1, wherein, The at least one rib (13) has a first outer surface that is in line with the radial line (R) and a second surface that is in line with the tangent line (G).

4. The screw boss according to any one of claims 1 to 3, wherein, The at least one rib (13) gradually narrows in the longitudinal direction from the base (11) toward the body (12).

5. The screw boss according to any one of claims 1 to 3, wherein, The at least one rib (13) extending outward from the body (12) has a demolding angle.

6. The screw boss according to any one of claims 1 to 3, wherein, The at least one rib (13) comprises a plurality of ribs (13), each rib being located at an off-center position coinciding with the tangent (G) of the opening (14).

7. The screw boss according to claim 6, wherein, Each of the plurality of ribs (13) radiates around the body (12) at uniform intervals.

8. The screw boss according to any one of claims 1 to 3, wherein the screw boss is configured for right-hand threaded fasteners, wherein, The at least one rib (13) is deviated from the radial line (R) in a counterclockwise direction.

9. The screw boss according to claim 1 or 2, wherein, The at least one rib (13) is offset far enough to not overlap with the radial line (R).

10. A component comprising a screw boss according to any one of claims 1 to 9.

11. The component according to claim 10, wherein, The component is configured for use in the assembly of a vehicle.

12. A method for mounting a first part to a base part, the method comprising: The screw boss according to any one of claims 1 to 9 is formed into the surface of the base part; Align the opening of the first part with the opening in the body; The fastener is inserted through the aligned opening and rotated in a direction opposite to the deviation of the at least one rib to engage the opening in the body and be driven into the opening in the body.

13. The method according to claim 12, wherein, The base component is part of the vehicle.

14. The method according to claim 12 or 13, further comprising: Align the opening of the second or additional part with the opening in the body.

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