HEAD SCREW

Description

[0001] The invention relates to a head screw with a longitudinally extended screw shank which has at least a partial thread, wherein a screw head is formed on an axial end of the screw shank, wherein the screw head has an end face in which a first recess designed as a screw head drive is provided, wherein the screw head has a first cylindrical section which adjoins the screw shank immediately, wherein the first section has a larger maximum diameter than a maximum screw shank diameter, wherein the screw head has a second section which adjoins the first section in the axial direction, the second section having a head plate which is spaced apart from the first section by a spacer element.

[0002] It is generally known that screws are used for a variety of tasks involving the detachable joining of two components, for example, or for securing one or more components to a single component. Over time, a wide variety of screw shapes and drive systems for screws have been developed for this purpose.

[0003] A commonly used screw is the so-called head screw, which, unlike the grub screw, for example, has a screw head with a drive system that has a larger diameter than a screw shaft that has a screw thread.

[0004] Screw threads also come in a wide variety of designs, each adapted to the specific fastening task. For example, if a screw is to be driven into wood, the screw thread is designed accordingly. Metric threads are frequently used when driving screws into metals or plastics. An example of this is the socket head cap screw according to ISO standard 4762, which has a metric thread on its shank and a cylindrical screw head. A drive system for the screw is also located on one end face of the screw head, for example, with a hex socket, a Torx, or a Phillips head drive.

[0005] All these screw types share the disadvantage that they cannot be easily screwed into the designated position in all installation situations. Even when screwing them in horizontally, the screw usually falls off the driving tool, such as a screwdriver, due to gravity. To prevent this, assembly aids are used; in the simplest case, for example, the installer's hand or pliers to hold the screw while it is being driven in. The screw or the screwdriver can also be magnetic, so that certain screws adhere magnetically to the screwdriver. However, this significantly limits the choice of screw materials and does not work in every screwing direction, and only with relatively small screws whose weight is so low that the magnetic forces can hold them in place.

[0006] However, even when driving screws into locations with limited access, such as at the end of narrow gaps or in recesses of molded parts or housings, it can easily happen that even magnetically held screws fall off the driving tool due to unintentional contact with the housing or molded part and potentially remain in an inaccessible location. Particularly when inserting screws into electrical control cabinets, especially those for low-voltage systems up to 1000V, such lost metal screws can cause significant problems during commissioning or operation of the cabinet, for example, by causing a short circuit when they fall out.

[0007] EP 1 382 863 A1 shows a screw with a specially shaped head with recesses for a matching screw attachment, a cylindrical area below the head with graduated diameters and radial shoulders, so that the attachment can securely grip the screw and transmit torque.

[0008] Based on this state of the art, the object of the invention is to provide a head screw which, even in difficult assembly situations, can be screwed into its intended position using only a screwing tool and without separate assembly aids.

[0009] The problem is solved by a head screw according to claim 1.

[0010] The basic idea of ​​the invention is that a screw head is designed with a head plate configured as described above, which can be temporarily connected to a holding and screwing tool for the screwing process in a particularly simple manner. "Connectable" in this sense means that the screw head is attached to the holding tool in such a way that it cannot be lost, allowing a person to position and hold the holding tool with the screw head in any direction with one hand, or to attach and screw the screw head into the desired position, especially when the screw is to be screwed in against the direction of gravity. For this purpose, the head plate has a predetermined thickness and features secondary recesses through which the holding tool's retaining elements can pass if necessary, clamping the head plate to the holding tool at its end face and on its underside, i.e., on the side of the head plate facing the screw shank.To ensure that the head plate can be securely clamped to the holding tool in an area around the second recesses, the spacer element in this area is spaced away from the relevant second recess by every second recess.

[0011] In an advantageous embodiment, the screw head is characterized by the fact that at least one second screw head drive is arranged on the head plate. A first screw head drive is often a slotted, Phillips, hex socket, Torx, or Torx Plus drive. However, those skilled in the art are familiar with many other possible screw head drives. For example, to avoid frequent tool changes, it is advantageous to have a second screw head drive on the head plate in addition to the first. For instance, it is particularly easy to combine an existing Phillips drive with a slotted drive as a second screw head drive and, if necessary, to provide a third screw head drive on a surface of the head plate.In a conventional design of the screw head drive, the driving tool tends to rotate out of the screw head drive when the screw is driven in, potentially damaging the screw head drive in the process. This is known as the come-out effect. To counteract this come-out effect, the invention provides straight flanks on the screw head drive. Straight flanks are defined as those surfaces on the screw head drive that can be described as the cylindrical surface of the screw head drive and are straight when they are parallel to a screw head axis of the screw head. Another preferred embodiment of the screw head provides that the second recesses are through holes. Accordingly, the second recesses do not necessarily have to be located in the radially outer region of the head plate and thus not be part of the cylindrical surface of the head plate.According to the invention, the second recesses are formed from the circular areas of two circles that partially overlap. This makes it particularly easy to insert the retaining elements of the screwing tool into the second recesses and clamp them in place by the guiding effect of the through holes on the head plate.

[0012] Furthermore, it is advantageous if the screw head is characterized in that the spacer element on the side of the head plate facing the spacer element is spaced from the second recesses by at least two recesses, and a clearance surface is formed around each second recess, on which at least one locking lug is formed, or at least one groove or a third recess is formed. A locking lug, a groove, or a third recess allows for a particularly simple snap-fit ​​connection between a correspondingly designed retaining element and, for example, the locking lug. It is equally easy for a person skilled in the art to implement a snap closure or to use the groove, the locking lug, or the third recess for locking the retaining element.The design of the screw head with locking lugs, grooves, or a third recess also prevents unintentional loosening of the screw head from the retaining element. Furthermore, the design of the locking lug, groove, or third recess allows for the specification of the necessary force or minimum torque to achieve a locking or latching action.

[0013] A preferred variant of the cap screw features the second recesses having a predetermined distance from an imaginary screw axis along the longitudinal extension of the screw shank, and this predetermined distance is the same for several different maximum shank diameters. This design has the advantage that, using a specific holding tool with holding elements adapted to the predetermined distance, cap screws of various sizes, such as M4, M5, or M6 for metric threads, can be driven into corresponding threaded holes with the same holding and driving tool. A tool change is then no longer necessary.

[0014] Further advantageous design options can be found in the additional dependent claims.

[0015] The invention, further embodiments and further advantages will be described in more detail with reference to the exemplary embodiments shown in the drawings.

[0016] They show Fig. 1 a view of a first exemplary cap screw, Fig. 2 a view of a second exemplary cap screw, Fig. 3 a view of a third exemplary cap screw, Fig. 4 a view of a fourth exemplary cap screw, Fig. 5 a view of a fifth exemplary cap screw, Fig. 6 a view of a sixth exemplary cap screw, Fig. 7 a side view of the sixth exemplary cap screw, Fig. 8 a view of an arrangement of a sixth cap screw and a screw-in tool, Fig. 9 a view of a seventh exemplary cap screw, and Fig. 10 a top view of an eighth cap plate.

[0017] Fig. 1Figure 1 shows a three-dimensional view of a first cap screw 10 with a screw shank 12 provided with a metric thread 14. The metric thread 14 is chosen only as an example, and those skilled in the art are free to use other thread forms, such as a wood thread. In that case, the shape of the screw shank is adapted accordingly to the chosen thread form. A wide variety of materials are also known to those skilled in the art for the choice of material for the first cap screw 10, including metals, alloys, ceramic materials, or even plastics. At a first end of the screw shank 12, a first screw head 16 is formed on the screw shank 12. This head has a first section 18, which in this example is cylindrical and has a larger diameter than the diameter of the screw shank 12.This ensures that when the first cap screw 10 is screwed into a threaded hole, the one-piece cap screw 10 can only be screwed in up to a side of the first section 18 facing the screw shank 12. The first section 18 thus serves as a stop for the first cap screw 10 during screwing and also offers the possibility of clamping components between the screw head 16 and a component with the threaded hole, for example washers, snap rings or electrical connection rings.

[0018] The screw head 16 has a second section 20, which adjoins the first section 18 in the axial direction, in the direction of a screw axis 22 indicated in the figure by a dashed line, i.e., upwards in the figure shown. The second section 20 has a first head plate 24, which is spaced apart from the first section 18 by a spacer element 26. The diameter of the spacer element 26 is smaller than the maximum diameter of the first head plate 24 and also smaller than the diameter of the first section 18.

[0019] The first head plate 24 has a first recess 30 on an end face 28 of the first screw 10, which is designed as a first screw head drive – in this example, a Torx screw head drive. Furthermore, a surface of the recess for the Torx screw head drive is located parallel to the screw axis 22, so that the position of the surface of the recess advantageously counteracts the so-called come-out effect when the screw is tightened. A surface of the first head plate 24 is designed such that this surface has an external hexagon drive 32 as a second screw head drive – similar to a hexagonal screw head. In addition, the first head plate 24 has six second recesses 34, which are designed as through-holes, with each second recess 34 having a length corresponding to the thickness of the first head plate 24.The shape of each second recess 34 – as seen in a top view of the end face 28 – corresponds to a partial surface of two imaginary, partially overlapping full circles, modeled on the shape of an 8. A screwing tool for connecting the first cap screw 10 enters the first imaginary full circle and, through a rotational movement around the screw axis 22, is moved past the tapered section of the 8 into the second full circle, thus connecting the first cap screw 10 to the first cap plate 24. This process will be explained in more detail in a later figure. In the chosen example, the lateral surfaces of the second recesses 34 also form part of a cap plate lateral surface of the first screw plate 24.Furthermore, the shape of the second recesses 34 is selected such that an insertion tool with correspondingly shaped projections extends through the second recesses 34 and clamps itself against the side of the head plate 24 facing the first section 18 with correspondingly shaped clamping elements, i.e., clamps itself in a free space in the radial direction around the spacer element 26. In this way, the first head screw 10 is firmly but releasably connected to the insertion tool. With a corresponding design of the insertion tool, this clamping is possible both when turning the first head screw 10 clockwise and counterclockwise. The interaction of the insertion tool and a head screw according to the invention is described in the following section. Figure 6 explained in more detail.

[0020] The Fig. 2Figure 1 shows a second cap screw 40, again with the screw shank 12, to which a second screw head 42 is integrally formed. A key difference from the first screw head 16 is that the diameter of the first section 18 and the diameter of the spacer element 26 are identical, so that they function as a single component of the second cap screw 40. However, the combined diameter is larger than the diameter of the screw shank 12. A head plate of the second screw head 42 is designed in the same way as the first head plate 24.

[0021] The Fig. 3Figure 1 shows a third screw 44 with the same screw shank 12, but with a third screw head 46 integrally formed on it. In the third screw head 46, the diameter of the first section 16 and the diameter of the spacer element 26 are also the same, and this common diameter is larger than the diameter of the screw shank 12. In contrast to the second screw head 42, the third head plate 48 has rounded, tongue-like ribs as radially outer limiting elements. With this design, the manufacture of the third screw 44 is advantageously simplified and also cost-effective. Furthermore, the rounding of the tongue-like ribs advantageously prevents the third screw 44 from snagging on an object in the vicinity of the screw-in point during tightening.

[0022] The Fig. 4Figure 1 shows a fourth cap screw 50 in a three-dimensional view, which is constructed similarly to the first cap screw 10, namely with a screw shank 12, a first section 18, and a second section 20, wherein the second section is spaced apart from the first section 18 by a spacer element 26, which is a fourth cap plate 52. The fourth cap plate 52 has six second recesses 34, which are designed as through holes through the axial extent of the fourth cap plate 52. In a top view of a fourth end face 56 of the fourth cap plate 52 with a Torx drive as the first recess 30, each second recess 34 looks approximately like two partially overlapping circular surfaces, with the imaginary centers of the two circular surfaces of each of the second recesses 34 lying on an imaginary circle around the screw axis 22.The radius of the imaginary circle is chosen such that the maximum radius of the spacer element 26 is smaller than the smallest distance of the nearest point of a second recess 34 to the screw axis 22. The advantage of such an embodiment of the invention is that both the screw shank and the maximum diameter of the fourth head plate 52 can assume different diameters, with the respective fourth head screws 50 being held with the same screw-in tool and, if necessary, screwed into the corresponding threaded holes.

[0023] The second exceptions 34, comparable to the second exceptions 34, which are in the Figures 1 to 3 shown, have a comparable shape, the shape of the second recesses 34 being in comparison to the second recesses made of Fig. 1These are only limited at their radial outer edge by the radial outer end of the respective head plates, and thus the two imaginary circular areas are cut off in their radial outer regions.

[0024] The Fig. 5Figure 5 shows a fifth cap screw 60, which has a similar design to the fourth cap screw 50, except that while the fifth cap plate 62 has the same maximum diameter as the fourth cap plate 52, its cylindrical surface is designed as a screw head drive, specifically as an external hexagon drive. The fifth cap plate 62 thus has six flat surfaces 64 evenly distributed around its circumference. This allows the user to select one of several possible tool types to operate the fifth cap screw 60. These flat surfaces can also extend onto the first section 18, which is not shown in the figure.

[0025] The Figs. 6 and 7Figure 1 shows a sixth cap screw 66 in a three-dimensional view and in a side view with a screw shank 12 and a first section 18 and with a second section 20. The second section 20 of the sixth cap screw 66 has a sixth head plate 68 and a sixth spacer element 70. The sixth head plate 68 has a circular cylindrical shape with a predetermined thickness 72, wherein the cylindrical shape of a radially outer surface of the sixth head plate 68 is interrupted by the six second recesses 34.

[0026] In the side view of the sixth head screw 66, it can be seen that the sixth spacer element 70 has a cylindrical base body 74 which has the same diameter as the first section 18. Six web-like projections 76 are arranged on the base body 74, the radially outer end of each projection 76 having the same radial distance to the screw axis 22 as the maximum diameter of the sixth head plate 68. In addition, the web-like projections 76 have an axial extension that corresponds to the axial thickness of the sixth spacer element 70.

[0027] In the Figure 6It is clearly evident that every second recess 34, viewed from the top of the front face 28, is approximately W-shaped and, as explained in more detail above, can be considered part of circular segments of two full circles. In a side view, it is apparent that the second recess 34 can be divided into a left partial recess and a right partial recess, with a central web of the imaginary W of the W-shaped form forming the dividing line between the left and right partial recesses. It is visible that in the area of ​​the right partial recess, each web-like projection 76 has the specified thickness 72, while in the area of ​​the left partial recess, the web-like projection 76 is spaced apart from the left partial recess.

[0028] In comparison to the first 10, second 40, and third cap screws 44, the design of the features on the sixth spacer element 70 limits the reach of a screw-in tool and the use of retaining fingers on the screw-in tool to only one direction of rotation of that single screw tool – in the example shown, clockwise rotation. This design is particularly advantageous for the use of safety-relevant cap screws. Accordingly, the retaining fingers on the screw-in tool are adapted to the direction of rotation. Thus, when using cap screws with left-hand threads, the corresponding screw-in tool is designed with retaining fingers in the left-hand direction. If both tightening and loosening of the cap screw are to be secured against loss, the screw-in tool is designed with retaining fingers for each direction of rotation. The features on the sixth spacer element 70 are then adapted to the use of retaining fingers in both directions.

[0029] The Fig. 8Figure 1 shows a three-dimensional view of an arrangement of a sixth cap screw 66 and an insertion tool element 80, which is equipped with a standardized bit connection and is therefore particularly easy to connect to a screw retainer. In the example shown, the insertion tool element 80 has six approximately L-shaped retaining fingers 82 on a side facing the sixth cap screw. These fingers are arranged such that, during axial movement of the insertion tool element 80 towards the sixth cap screw 66, they extend through the second recesses 34. During rotation of the insertion tool element 80 about the screw axis 22 towards a free end of the L-shaped retaining fingers 82, a short transverse projection of the retaining fingers 82 engages the sixth cap plate 68 and clamps it between the transverse projection and the side of the insertion tool element 80 facing the cap screw.This ensures that the sixth cap screw 66 is firmly, yet releasably, connected to the insertion tool element 80, thus guaranteeing that the sixth cap screw 66 follows every movement of the insertion tool element 80. In this way, the sixth cap screw 66 can be safely guided and positioned in any spatial direction and screwed into a desired position in any desired spatial direction.

[0030] The Fig. 9Figure 1 shows a three-dimensional view of an arrangement of a seventh countersunk screw 84, which is designed as a countersunk screw and whose countersunk head is partially cut away. The insertion tool element 80 is inserted into the seventh countersunk screw 84 and secured by means of retaining fingers 82. The seventh countersunk screw 84 has a seventh head plate 86, to which, in the axial direction up to the thread 14, first the seventh spacer element 89 and then the first section 18 are attached. The seventh spacer element 89 and the first section 18 have an imaginary frustoconical enclosing shape, which tapers from the diameter of the seventh head plate 86 to the diameter of the screw shank 12.The figure clearly shows that the seventh head screw 84 also has second recesses 34 and that the seventh spacer element 89 is designed such that the retaining fingers 82 of the screwing tool element 80 clamp the seventh head plate 86 to the screwing tool element 80.

[0031] Fig. 10Figure 1 shows a top view of an eighth head screw 90 with an eighth head plate 92. The figure is intended to illustrate the basic structure of a head plate. The six second recesses 34 are visible in the eighth head plate 92. A first circle 94 is drawn at the radial outer boundary of each recess, and a second circle 96 at the radial inner boundary. This is intended to show, in particular, that all outer and inner boundaries lie on a circular arc. To illustrate the top view of the second recesses 34, a first circular bore 98 and a second circular bore 100 are shown in one of the second recesses 34, namely in the second recess 34a. These bores were used to create the second recess 34a. It is evident that the approximately figure-eight shaped second recesses 34 were formed by the overlapping circular shapes of the bores.

[0032] For example, the insertion tool element 80 with its six retaining fingers 82 can be placed onto the eighth head plate 90 such that the retaining fingers 82 each engage in a second recess 34, pass through it, and can be moved from a first position to a second position by a clockwise rotation. In the first position, the retaining fingers 82 can be inserted into and passed through the second recesses. In the second position, the retaining fingers 82 are clamped to the eighth head plate 92 and thus firmly, yet releasably, connected to it. In addition to the clamping action, a locking lug 102 is provided, which is located in a radially internal projection within a waist of the figure-eight-shaped second recess 34.To release the insertion tool element 80 from the eighth head plate 92, it is simply turned counterclockwise, thus releasing the clamping mechanism and allowing the retaining fingers 82 to be removed from the second recesses 34. Instead of clamping, the eighth head plate 90 and / or the retaining fingers 82 can also be designed for a snap-fit ​​connection. Furthermore, the eighth head plate 92 also incorporates a screw head drive 104, designed as a Torx screw head drive. However, any other suitable screw head drive, such as a slotted, Phillips, or hex socket drive, can also be used. Alternatively, no additional screw head drive needs to be provided on the screw head at all. The second recesses 34 already serve as the screw head drive. Reference symbol list

[0033] 10 First cap screw 12 Screw shank 14 Thread 16 First screw head 18 First section 20 Second section 22 Screw axis 24 First head plate 26 Spacer 28 End face 30 First recess 32 External hexagon drive 34 Second recesses 40 Second cap screw 42 Second screw head 44 Third cap screw 46 Third screw head 48 Third head plate 50 Fourth cap screw 52 Fourth head plate 56 Fourth end face 58 Torx drive 60 Fifth cap screw 62 Fifth head plate 64 Flat surface 66 Sixth cap screw 68 Sixth head plate 70 Sixth spacer 72 Thickness 74 Base body 76 Web-like projections 80 Insertion tool element 82 Retaining finger 84 Seventh cap screw 86 Seventh head plate 88 seventh spacer element 90 eighth head screw 92 eighth head plate 94 first circle 96 second circle 98 first bore hole 100 second bore hole 102 detent lug 104 screw head drive

Claims

1. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) having an elongate screw shank (12) which at least partially has a thread (14), wherein a screw head (16, 42, 46) is integrally moulded on an axial end of the screw shank (12), wherein the screw head (16, 42, 46) has a first portion (18) which directly adjoins the screw shank (12), wherein the first portion (18) has a larger maximum diameter than a maximum screw shank diameter, wherein the screw head (16, 42, 46) has a second portion (20) which adjoins the first portion (18) in the axial direction, wherein the second portion (20) has a head plate (24, 48, 52, 62, 68, 86, 92), which is spaced apart from the first portion (18) by a spacer element (26, 70, 88), wherein an end side (28) of the head plate (24, 48, 52, 62, 68, 86, 92) has at least two second recesses (34) which have a length in the axial direction that corresponds to an axial length of the head plate (24, 48, 52, 62, 68, 86, 92), and wherein the at least two second recesses (34) are disposed on the head plate (24, 48, 52, 62, 68, 86, 92) in such a way that the at least two second recesses (34) are spaced apart from the spacer element (26, 70, 88) on a side of the head plate (24, 48, 52, 62, 68, 86, 92) that points towards the spacer element (26, 70, 88), characterized in that a shape of each second recess 34, as seen in the plan view of the end side 28, corresponds to at least a partial area of two imaginary partially overlapping full circles.

2. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) according to Claim 1, characterized in that the screw head (16, 42, 46) has an end side (28) in which a first recess (30) in the form of a screw head drive (104) is present.

3. Headed screw (10, 40, 44, 50, 66, 84, 90) according to Claim 1 or 2, characterized in that at least one second screw head drive is disposed on the head plate (24, 48, 52, 62, 68, 86, 92).

4. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) according to one of the preceding claims, characterized in that the second recesses (34) are through holes.

5. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) according to one of the preceding claims, characterized in that the spacer element (26) on the side of the head plate (24, 48, 52, 62, 68, 86, 92) that points towards the spacer element (26) is spaced so far apart from the second recesses (34) that in each case one clearance surface, on which at least one latching cam is integrally moulded or at least one groove or a third recess is incorporated, is formed about each second recess (34).

6. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) according to one of the preceding claims, characterized in that the end side (28) of the head plate (24, 48, 52, 62, 68, 86, 92) has six second recesses (34).

7. Headed screw (10, 40, 44, 50, 60, 66, 84, 90) according to one of the preceding claims, characterized in that the second recesses (34) are approximately 8-shaped.