FOR

ROUND TOP SET SCREW AND APPLICATION THEREOF

CROSS REFERENCE

{081} This application claims the benefit of U.S . Patent Application serial No. 13/941 ,648, filed on July 15, 20 i 3.

BACKGROUND

{082] A set screw is generally used, to secure two parts together by screwing through one part tightl upon or into aoother part to prevent relative movement. A typical set screw is fully threaded and driven with an intemai-wrenching drive such as a socket, having a cross- sectional shape of a hexagon, a star, a square, a slot, a cross, etc. These screws are generally made of alloy or stainless steel and used for a wide variety of applications, for example, for securing parts in rotating items such as door knobs, pulleys or wheels.

BMEF DESCRIPTION OP THE DRAWINGS [«©3| FIG. 1 illustrates aft example of a conventional set screw.

|804J FIG. 2A illustrates a conventional metal plate, and FIG . 2B illustrates an example of an application of conventional set screws using the conventional metal plate.

{085} FIG. 3 A and FIG. 3B are a top plan view and an eievationai view, respectively, of an example of a round top set scre w according to an embodiment

[8Θ6] FIG. 3C and FIG, 3D are a top plan view and an. eievationai view, respecti vely, of aft example of a out to be engaged with the screw.

|98?] FIG. 3E and FIG. 3F are a top plan view and an eievationai view of a combination of the round, top set screw and the nut.

{008} FIGS. 4A - 4F illustrate details of a wrenching tool for attaching a round top set screw and a nut to a base board.

i |005>] FIGS. 5 A - 5C illustrate an example of a process of using the tool for attaching a round top set scre to a base board and securing it by using a corresponding nut.

[ββ 10] FIGS. 6 A - 6C illustrate another example of a process of using the too! for attaching a round top set screw to a base board and securing it by using a corresponding nut.

DETAILED DESCRIPTION

(00 It] FIG. ! illustrates an example of a conventional set screw. This specific example is a hex socket set screw, which is provided with a socket 104 at one end portion of the screw, the socket having a horizontal cross-sectional shape of a. hexagon for wrenching drive. The horizontal cross-sectional shape can be of a star, a square, a rectangle, a slot, a cross, etc., and a corresponding wrench or a screw driver is used for screwing. The other end portion .108 of the screw, often referred to as a point, can be designed to be flat, cup shaped, cone shaped, dome shaped, etc. The present example has a fiat point and a side surface 1 12 that is fully threaded. The top surface of the set screw, where there is an opening of the socket 104 and the thread formation ends, is generally fiat, hence forming a sharp edge 1 i 6,

£0012] FIG. 2A illustrates a conventional metal plate, and FIG. 2B illustrates an example of an application of conventional set screws. An array of multiple set screws is used to form an apparatus 200 for flattening a metal plate. The number of set screws used for this purpose may be on the order of 10 ~ 100 or mo , depending on the size and warpage of the metal plate and the required flatness tolerance (for example, within 0.05mm). The apparatus 200 includes three set screws 204-1 , 204-2 and 204-3 and a base board 208 in this example. Each set screw is screwed into the base board 208 by a specific length: the screw 204-1 is screwed in by a largest length; the screw 204-3 is screwed in by a smallest length; and the screw 204-2 is screwed in by an intermediate length. Each scre w can be screwed down and up by engaging a wrench or a screw driver with the socket formed at the top end portion of the screw- until it reaches a predetermined height above the base board. Thereafter, the screw can be secured to the base board 208 at the desired position using a fastener, such as a nut, a clip, a ring, etc. In this example of FIG. 2B, the three set screws 204-1 , 204-2 and 204-3 are coupled with three fasteners 212-1, 21 2-2 and 212-3, respectively. Therefore, the height of each screw with respect to the top surface of the base board 208 can be adjusted by unlocking the fastener, vertically positioning the screw and re-tightening the fastener, [0 13J The height: of each screw can he predetermined depending on the warpage of the metal plate to be flattened. As schematically illustrated in FIGS. 2A and 2B„ the metal plate is originally warped downward with gradually increasing degree toward the right direction in this example. The heights of the three screws 204-1, 204-2 and 204-3 can he predetermined or adjusted so that, when the metal piate is pressed against the screws, the metal plate gets warped upward with gradually increasing degree toward the right direction. As a result of the compression exerting opposite to the original warpage, the flatness of the metal plate within a required tolerance can be achieved by the spring back action when the metal plate is removed from the apparatus 200,

0014] Conventional set screws, sue!i as shown in FIG. 1, may he used to construct the apparatus 200 for flattening a metal plate. However, the top end portio of a set screw generall has a sharp edge, such as the edge 1 16 of the example illustrated in FIG. 1.

Therefore, when a warped metal plate is pressed against a conventional set screw, it is likely that the sharp edge of the screw touches the metal plate, for example, as indicated at a location 2.16, thereby generating dents, scars, scratches, or other damages on the surface of the metal piate,

[0015] In vie of the above problems associated with using conventional set screws for an apparatus for flattening a metai plate, the present document describes a new type of set screw t at can minimize damages to a metal plate when the metal plate is pressed against an array of the set screws having different heights in the apparatus for flattening the metal plate. Details of the ne type of set scre and applications thereof according to present embodiments are explained below with reference to the subsequent drawings.

|00I6] FIGS, 3 A and 3B illustrate an example of a round top set screw 3-00A according to an embodiment. The top view and the side view are illustrated. The screw 300A has three sections 304, 308 and 31 2 formed contiguously and concentrically. The first section 304 is a main body that has a shape of substantially a cylinder with a diameter Dl and a length LI that can be predetermined depending on the intended use and application. The side surface of the first section 304 is threaded. The second section 308 is a neck portion configured for wrenching dri ve. In this example, the shape of the second section 308 is substantially a hexagonal prism. That is, the horizontal cross-sectional shape of the second section 308 is a hexagon with a diagonal D2; however, a shape of a star, a square, a rectangle or other polygon can be used to form a corresponding polygonal pri m for the second section 308. The shape and dimensions of the second section 3 8, such as the hexagonal diagonal D2 and the length L2, can be predetermined depending on the wrenching efficiency and other factors. The diagonal D2 of the second section 308 in this example is smaller than Dl . The third section 312 is a head portion having a cylindrical portion and a round top 316. The round top 316 has a convex shape, the edge of which contiguously connects to the side surface of the cylindrical portion of the third section 312. The cylindrical portion has a diameter D3 and a length L3. The curvature of the convex can be predetermined so as to prevent damages to the metai plate when pressed at an angle against the third section 312, i.e. , the head portion of the screw. The dimensions D3 and/or L3 can also be varied so as to optimize the tip strength while preventing the damages to the metai plate. For example, 1.3 can be made as small as possible, such as nearly zero, to minimize the protrusion of the third section 312 from the second section 308.

[00.17] FIGS. 3C and 3D illustrate an example of a nut 300.B to he engaged with the screw 300A of FIGS. 3 A and 3B. This specific example is a conventional nut having a horizontal cross-sectional shape of a hexagon. The top view and the side view are illustrated. A thread 320 is internally formed (not visible tn FIG. 3D), and the pitch of the thread 320 of the nut 300B is configured to correspond to the pitch of the thread of the main body 304 of the screw 3O0A for engaging. This particular nut 3 GOB illustrated in FIGS. SC and 3D is chamfered at the corners 324 to reduce deformation and/or crushing of the nut by the wrenching action, ft is also possible to use an unchamfered nut.

[0018] FIGS. 3E and 3F illustrate a combination of the round top set screw 300A and the nut 300B. These two parts are engaged with each other throug the threads. The individual parts may be prepared to be combinations beforehand, so that the paired parts are already together without losing each other. Additionally, the screw and the corresponding nut can be tightened and locked to each, other, and the combination of locked parts can be used as one integrated part for certain applications.

[0019] Referring back to FIG, 2B, the conventional set screws are used to construct the apparatus for flattening a metal plate, where the metal plate is often damaged due to the sharp edge 1 16 at the top end portion of the conventional set screw as illustrated in FIG. 1 when the warped metal plate is pressed against the conventional set screw at an angle, such as indicated at the location 216, in place of the conventional set screws, the round top set screws, as illustrated in FIGS. 3A and 3B, can be used to construct the apparatus. Due to the round top 316 formed hi the third section 312 of the set screw 300A in FIGS. 3A and 3B, the metal plate is prevented from touching a sharp edge even when pressed against the screw at an angle. Therefore, it is possible to prevent damages to the metal plate during the pressing operation by using the round top set screws having different heights.

0 2 J FIGS. 4A - 4F illustrate details of a wrenching tool for attaching a round top set screw and a nut to a base board. This tool can be used, for example, for attaching each of the round top set screws to the base board and securing it by using the corresponding nut, so as to construct the apparatus for flattening a metal plate. This tool comprises two units: one unit A configured to act on. a round top set screw and the other unit B configured to act on a nut FIGS. 4A and 4B and FIGS. 4C and 4D illustrate the units A and B, respectively. FIGS. 4E and 4F illustrate the tool when the units A and B are combined by coupling vertically and concentrically to each other. In FIGS. 4A - 4F, the top views and the cross-sectional side views with respect to the vertical cut through the lines iVA-iVA, iVC-iVC, and IVE-iVE, respectively, are illustrated.

{00211 The unit A illustrated in FIGS. 4A and 4B includes a handle 404A and a cylinder 408A. The handle 404A is horizontally fixed to the top end portion of the cylinder 4G8A. As such, the cylinder 408A can be rotated around the cylindrical axis by turning the handle 404A with a hand or another tool. The center of the handle 404A is configured to coincide with the cylindrical axis of the cylinder 408A, in this example. However, only one arm or an asymmetric attachment of the handle 404A is also possible. The cylinder 40 has two sections. The first section 41 OA forms a solid cylinder. The second section has a hollow therein, hence having an internal side surface 412A, which is formed concentric with the outer side surface of the cylinder 408.4. The horizontal cross section of the internal side surface 412 A is hexagonal In shape in this example. The shape and dimensions of the internal side surface 412A can be predetermined or adjusted such that the second section of a round top set screw can be engaged for effective wrenching. Specifically, with reference to FIGS. 3A and 3B, the second section 308 of the round top set screw 300 can be engaged with the internal side surface 412A of the unit A for the wrenching purpose. The horizontal cross section of the interna! side suriace 412A may not be limited to a hexagon, but a rectangle or other shape may be used as Song as the engagement with the screw 300A can be made effectively for wrenching. [0022] The unit B illustrated in FIGS. 4C and 4D includes a handle 404B and a hollow cylinder 408B. The handle 40 B is horizontally fixed to rite top end portion of rite hollow cylinder 408B. As such, the hollow cylinder 408 B can be rotated around the cylindrical axis by turning the handle 4MB with a hand or another tool. The center of the handle 4MB is configured to coincide with the cylindrical axi of the hollow cylinder 408B, in this example. However, only one arm or an asymmetric attachment of the handle 4048 is also possible. The hollow cylinder 408B has two sections having two different internal side surfaces 4108 and 4! 2B _; respectively. The first internal side surface 41 OB is formed cylindrical and concentric with the outer side surface of the hollow cylinder 408B. The second internal side surface 412B is formed concentric with the outer side surface of the hollow cylinder 408B. and the horizontal cross section of the second internal side surface 412B is hexagonal in shape in this example. The shape and dimensions of the second internal side surface 412B can be predetermined or adjusted such that a nut can be engaged for effective wrenching.

Specifically, with reference to FIGS. 3C and 3D, the nut 30ΘΒ can be engaged with the internal side surface 412B of the unit B for the wrenching purpose. The horizontal cross sec tion of the internal side surface 12B may not be limited to a hexagon, but a rectangle or other shape may be used as long as the engagement with the nut 300B cart be made effectively f r wrenching.

[0023] The tool 400 illustrated in FIGS, 4E and 4F is a combination of the unit A and the unit B, which are coupled concentrically to each other to be used to act n a combination of a nut and a round top set screw. The diameter of the cylinder 408A of the unit A can be made smaller than the diameter of the horizontal cross section of the first internal side surface 410B of the unit B so that the cylinder 408A can be inserted smoothly into the hollow cylinder 408B.

[0024] FIGS. 5A ----- 5C illustrate an example of a process of using the tool 400 for attaching a round top set screw to a base board and securing it by using a corresponding nut. Initially, a round top set screw and a corresponding nut may be tightened and locked to each other through the threads to form a combination of the two. For example, the nut 300B as illustrated in FIGS. 3C and 3D may be locked to the round top set screw 30 A as illustrated tn FIGS. 3 A and 3B, to form combination as illustrated in FIGS. 3F and 3F. FIG. 5A illustrates a first step where the combination of the round top set screw 300 A and the nut 300B is wrenched by engaging the nut 300B with the second internal side surface 412B of the unit B to screw in the round top set screw 300A to a certain depth in the base board 504. FIG. 5B iliustrates a second step where the unit A is inserted into the unit 8 vertically and coupled concentrically with the unit B so that the unit A can act on the screw 300A, while the unit B acts on die nut 300B. In diis configuration, the round top set screw 300A and the nut 3O0B can be unlocked from each other by wenching the two pails with die corresponding units, respectively, specifically by engaging the nut 300B with the second internal side surface

412B of the unit B and engaging the second section 308 of the screw 300A with the internal side surface 412A of the unit A. Thereafter, the height of the round top set screw 300A may be adjusted to have a predetermined height by wrenching by engaging the second section 308 of the screw 300 A with the internal side surface 412A of the unit A. Once the predetermined height is reached, the nut 300B ma be wrenched by engaging the nut 300B with the second internal side surface 4 J 2B of the unit B„ while engaging the second section 308 of the screw 300 A with the internal side surface 412 A of the unit A, to lock itself to the round top set screw 300A and secure the screw 300A to the base board 504, in a third step as illustrated in FIG. SC. Thereafter, the units A and B may be removed.

{0025) FIGS. 6A - 6C illustrate another example of a process of using the tool 400 for attaching a round top set screw to a base board and securing it by using a corresponding nut. Initially, a round top set screw and a corresponding nut may be separated. FIG. 6A illustrates a first step where the round top set screw 300A is wrenched fay engaging the second section 308 of the screw 300 A with the internal side surface 412 A of the unit A to screw in the round top set screw 300A to a certain depth in the base board 604. FIG. 6B iliustrates a second step where the unit A is removed, and the unit B is used to couple the nut 300B with the screw 300A through the threads. For this operation, die outer side surface of the nut 300B may be engaged with the second internal side surface 4.12B of the unit B. FIG. 6C illustrates a third step where the unit A is inserted into the unit B vertically and coupled concentrically with the unit B so that the unit A can act on the screw 300A, while the unit B acts on the nut 300B. Thereafter, the height of the round top set screw 300A may be adjusted to have a

predetermined height by wrenching by engaging the second section 308 of the screw 300A with the internal side surface 412A of the unit A. Once the predetermined height is reached, the nut 300B may be wrenched by engaging the nut 300B with the second internal side surface 412B of the unit B, while engaging the second section 30S of the screw 300A with the internal side surface 412A of the unit A, to Sock itself to the round top set screw 300A and secure the screw 3Θ0Α to the base board 604. Thereafter, the units A and B may be removed.

[9026] While this document contains many specifics, these should not be construed as limitations on the scope of an invention or of what may be claimed, but. rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context, of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination:. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be exercised from the combination, and the claimed combination may be directed to a subcombination or a variation of a subcombination.