A device for installing vandal-resistant fasteners

Abstract

The utility model relates to a hand-held and portable assembly tool for threaded connections, namely to replaceable drive elements for assembling vandal-proof fasteners, in particular vandal-proof nuts and bolts with a special drive profile. A device for assembling vandal-proof fasteners comprises a housing (1) of cylindrical shape, at one end of which a first opening (2) is made, and at the opposite end - a second opening (3), limited by a concave spherical surface (4), on which hooks (5) are located, wherein each hook (5) comprises an end section (6), located perpendicular to the longitudinal axis of the housing (1), and an inclined surface conjugated with the concave spherical surface (4) of the second opening (3), and the height h of each hook (5) is from 0.045 to 0.060 of the diameter D of the second opening (3) along the outer edge.The technical result consists in reducing the specific contact load on the drive sections of the vandal-proof joint when transmitting a specified tightening torque. 4 clauses, 3 figs.

Description

[0001] Field of technology to which the utility model belongs

[0002] The utility model relates to a hand-held and portable assembly tool for threaded connections, namely to replaceable drive elements for assembling vandal-proof fasteners, in particular vandal-proof nuts and bolts with a special drive profile.

[0003] Technology Level

[0004] A tamper-resistant fastener is known from the prior art [AU2005317992B2, published 21.04.2011], comprising a fastening element with a dome-shaped or partially spherical surface on which recesses are made, and a special end tool with a recess and curved projections for interacting with the recesses of the fastening element.

[0005] A disadvantage of this analog is that the interaction between the curved projections of the end tool and the recesses of the fastener is primarily focused on forming a special engagement profile, which prevents the use of a conventional tool. Moreover, when transmitting tightening torque, the working contact between the tool and fastener is determined by the mating of the curved surfaces of the projections and recesses. This mating is sensitive to the relative position of the tool and fastener, since slight misalignment, incomplete fit, or process deviations in the profile can cause the actual contact zone to shift toward the edges of the mating surfaces. As a result, the tightening force is absorbed by a less stable contact patch, which can increase the local contact load on the drive sections of the vandal-resistant joint when transmitting a given torque.

[0006] Also known from the prior art is a tamper-evident fastener [US2008145181A1, published 06 / 19 / 2008], comprising a fastening element with a plurality of recesses, each of which has a curved concave surface and a curved convex surface, as well as a socket element with curved projections designed with the possibility of interacting with said recesses of the fastening element.

[0007] A disadvantage of this analog is that the profile interaction between the curved projections of the socket element and the concave and convex surfaces of the fastener recesses ensures torque transmission through the mating of complex curved surfaces. With this mating, the position and area of ​​actual contact depend on the manufacturing accuracy of the profile, the tool seating depth, and the tool's alignment with the fastener. If these conditions deviate, part of the force may be absorbed by the edge or short sections of the profile, resulting in increased local contact loading of the drive sections of the vandal-resistant joint when transmitting the specified tightening torque.

[0008] The closest in technical essence are safety nuts and bolts [GB2269644A, published 16.02.1994], comprising a fastening element with a body having a dome-shaped outer surface, a threaded hole and a plurality of grooves on the dome-shaped surface, as well as a tool with a recess for receiving the fastening element and working surfaces for engaging with the walls of the grooves.

[0009] The main technical challenge of the prototype is that the interaction between the tool's working surfaces and the fastener's groove walls occurs on a domed surface and is therefore sensitive to the stability of the tool's fit relative to the fastener. When transmitting tightening torque, even slight tool displacement, incomplete fit, or misalignment of the mating surfaces can alter the actual contact zone, resulting in the contact force being absorbed primarily by the edges of the working surfaces rather than by the stable mating surface. This can lead to a localized increase in contact pressure in the interface between the tool and the drive sections of the vandal-resistant joint, and therefore, reducing the specific contact load when transmitting a given tightening torque remains relevant.

[0010] Disclosure of the essence of the utility model

[0011] The technical problem, the solution of which is provided by the use of the declared utility model, consists in eliminating the shortcomings of the prototype.

[0012] The technical result of the utility model consists in reducing the specific contact load on the drive sections of the vandal-proof connection when transmitting a given tightening torque.

[0013] The objective manifestation of the specified technical result is a reduction in the calculated contact pressure in the zone of force interaction of the drive element with the drive sections of the anti-vandal connection when transmitting the same tightening torque.

[0014] The specified technical result is provided by a device for mounting vandal-proof fasteners, comprising a cylindrical body, on one end of which a first opening is made, and on the opposite end of which a second opening is made, limited by a concave spherical surface on which hooks are located, wherein each hook contains an end section located perpendicular to the longitudinal axis of the body, and an inclined surface conjugated with the concave spherical surface of the second opening, characterized in that the height h of each hook is from 0.045 to 0.060 of the diameter D of the second opening along the outer edge.

[0015] In a particular case, the first hole and the second hole are made coaxially to each other.

[0016] In this particular case, the first hole is made with a square cross-section to accommodate the head of an impact wrench.

[0017] In a particular case, on the inner surface of the second hole there are 3 to 10 hooks, evenly spaced around the circumference.

[0018] In this particular case, the flat end section of each hook is located on the left side of the hook when looking at the end of the housing with the second hole.

[0019] Brief description of drawings

[0020] Fig. 1 shows the general appearance of the claimed device.

[0021] Fig. 2 shows the claimed device, left view.

[0022] Fig. 3 shows the claimed device, right side view.

[0023] The figures indicate: 1 – body; 2 – first hole; 3 – second hole; 4 – concave spherical surface; 5 – hooks; 6 – end section.

[0024] Implementation of a utility model

[0025] A device for mounting vandal-proof fasteners comprises a body (1), at one end of which a first opening (2) is made, and at the opposite end of which a second opening (3) is made, limited by a concave spherical surface (4), on which hooks (5) are located.

[0026] Case

[0027] The housing (1) is cylindrical. The cylindrical shape of the housing (1) ensures the formation of the longitudinal axis of the device and determines the axial orientation of the device's structural elements relative to said longitudinal axis.

[0028] The housing (1) is made of a metal material that provides torque absorption during installation of the vandal-resistant fastener. Specifically, the housing (1) can be made of steel, such as 40KhFA steel according to GOST 4543-2013 or 40X steel according to GOST 4543-2013, with a hardness of 45 to 48 HRC.

[0029] The cylindrical housing (1) provides a rigid spatial base for the device during torque transmission. This design reduces the likelihood of deformational displacement of the device's working elements relative to the drive sections of the vandal-resistant fastener, which helps maintain the specified position of the force contact zones and reduces the specific contact load on the drive sections of the vandal-resistant fastener during transmission of the specified torque.

[0030] First hole

[0031] At one end of the housing (1) a first hole (2) is made, intended for coupling the device with a tightening tool, by means of which a torque is applied to the device.

[0032] The first hole (2) has a square cross-section to accommodate the head of an impact wrench manufactured in accordance with GOST 10210-83 "Hand-held pneumatic impact wrenches. Basic parameters." The square cross-section of the first hole (2) forms a seat for the impact wrench head and ensures the transmission of torque from the impact wrench head to the housing (1) due to the interaction of the edges of the impact wrench head with the inner surfaces of the first hole (2).

[0033] This design of the first hole (2) reduces the likelihood of relative tool rotation in the mounting area and facilitates torque transfer to the housing (1) without additional displacement of the load application direction. This maintains a stable position of the device relative to the vandal-resistant fastening joint, reducing the likelihood of edge contact force concentration and helping to reduce the specific contact load on the drive sections of the vandal-resistant joint when transmitting a given tightening torque.

[0034] Second hole

[0035] A second hole (3) is made at the end of the housing (1) opposite the end in which the first hole (2) is made. The second hole (3) forms the working part of the device, designed to interact with the drive part of the vandal-proof fastening connection.

[0036] The second opening (3) is bounded by a concave spherical surface (4). This concave spherical surface (4) forms the device's three-dimensional internal working area, facing the drive portion of the vandal-resistant joint. This surface ensures the placement of the hooks (5) on the inner surface of the second opening (3) and establishes a common spatial base for them.

[0037] The placement of the hooks (5) on the concave spherical surface (4) ensures their positioning within a common spatial working zone, corresponding to the volumetric nature of the drive section of the vandal-resistant joint. This reduces the likelihood of the actual contact shifting toward random edge areas of the profile during torque transmission, thereby reducing the specific contact load on the drive sections of the vandal-resistant joint when transmitting a given torque.

[0038] The second hole (3) can be made coaxial with the first hole (2). The coaxial arrangement of the first hole (2) and the second hole (3) ensures torque transfer from the tightening tool to the working part of the device along a common axis. This design reduces the likelihood of eccentric load application to the working part of the device, thereby reducing the likelihood of uneven loading of individual hooks (5) and reducing the specific contact load on the drive sections of the vandal-resistant joint when transmitting a given tightening torque.

[0039] Hooks

[0040] On the concave spherical surface (4) of the second hole (3) there are hooks (5) designed for direct interaction with the drive sections of the vandal-proof fastening connection and transmitting the tightening torque to them.

[0041] The inner surface of the second hole (3) is provided with 3 to 10 hooks (5), evenly spaced around the circumference. This arrangement ensures the distributed torque is distributed among multiple contact zones around the circumference. By distributing the force among multiple hooks (5), the load on each individual drive section of the vandal-resistant joint is reduced, thereby reducing the specific contact load when transmitting a given tightening torque.

[0042] Each hook (5) comprises an end section (6) located perpendicular to the longitudinal axis of the body (1) and an inclined surface mating with the concave spherical surface (4) of the second hole (3).

[0043] The end section of the hook (5) forms a working support surface designed to absorb the circumferential component of the force during tightening torque transmission. The position of the end section (6) perpendicular to the longitudinal axis of the housing (1) ensures its stable spatial orientation relative to the direction of torque application. As a result, when the device is rotated in the tightening direction, the end section (6) engages with the corresponding drive section of the vandal-resistant joint and absorbs the force not through a random edge area of ​​the profile, but through a predetermined working surface. This reduces the localized concentration of contact pressure and helps to reduce the specific contact load on the drive sections of the vandal-resistant joint.

[0044] The flat end section (6) of each hook (5) is located on the left side of the hook (5) when looking at the end face of the housing (1) with the second hole (3). This arrangement corresponds to the transmission of torque when tightening the vandal-proof fastening joint clockwise when looking at the end face of the housing (1) with the second hole (3). With this tightening direction, the end sections (6) of the hooks (5) form working support surfaces that receive the circumferential component of the force. The same orientation of the end sections (6) of all hooks (5) ensures their coordinated inclusion in the force interaction with the drive sections of the vandal-proof connection, which reduces the likelihood of preferential loading of individual hooks (5) and helps to reduce the specific contact load when transmitting a given tightening torque.

[0045] The inclined surface of the hook (5) is mated with the concave spherical surface (4) of the second hole (3). The inclined surface forms a transition section between the concave spherical surface (4) of the second hole (3) and the end section (6) of the hook (5). This design eliminates the formation of a sharp step in the transition zone from the base surface of the second hole (3) to the working support surface of the hook. When the device interacts with the drive part of the vandal-proof joint, the inclined surface facilitates a smoother entry of the hook (5) into the mating surface and reduces the likelihood that the contact force will be concentrated on the edge line of the transition. As a result, the contact force during the transmission of the tightening torque is distributed more smoothly in the mating zone of the hook (5) with the concave spherical surface (4), which helps to reduce the specific contact load on the drive sections of the vandal-proof joint.

[0046] The height h of each hook (5) is from 0.045 to 0.060 of the diameter D of the second hole (3) along the outer edge. The height h of the hook (5) is understood to be the amount of protrusion of the hook (5) relative to the adjacent concave spherical surface (4) of the second hole (3) in the direction of forming the working contact with the drive section of the vandal-proof connection. The diameter D of the second hole (3) along the outer edge is understood to be the diameter of the second hole (3), determined along its outer edge on the end of the housing (1).

[0047] The specified ratio of the height h of the hook (5) and the diameter D of the second hole (3) determines the protrusion of the hook (5) within the working area of ​​the second hole (3). When h is less than 0.045D, the hook (5) has an insufficient height for stable thrust engagement with the drive section of the vandal-proof joint, which may lead to a shift in the actual contact zone and incomplete perception of the circumferential component of the force. When h is greater than 0.060D, the protrusion of the hook (5) becomes excessive in relation to the size of the second hole (3), as a result of which the contact may acquire a more localized nature with an increase in pressure in the force interaction zone. Setting the height h within the range from 0.045 to 0.060 of the diameter D of the second hole (3) ensures sufficient engagement with the drive section of the vandal-proof joint while limiting excessive localization of the contact force, which helps to reduce the specific contact load when transmitting a given tightening torque.

[0048] When the end section, inclined surface, and the specified h / D ratio are combined, the hook (5) forms a working profile in which the end section (6) absorbs the main circumferential component of the force, the inclined surface reduces the abruptness of the transition to the concave spherical surface (4) of the second hole (3), and the height of the hook (5) ensures a sufficient, but not excessive, protrusion of the working section. This design contributes to the formation of a stable zone of force contact between the hook (5) and the drive section of the vandal-resistant joint and reduces the specific contact load when transmitting a specified tightening torque.

[0049] The device's combination of features ensures torque transmission from the tightening tool to the drive sections of the vandal-resistant joint via a coordinated axial force pattern. The first hole (2) receives torque from the tightening tool, the housing (1) transmits this torque to the second hole (3), and the coaxial arrangement of the first hole (2) and the second hole (3) reduces the likelihood of eccentric load application to the working part of the device. Due to this, the hooks (5) interact with the drive sections of the vandal-resistant joint while maintaining a more stable position of the device relative to the torque transmission axis.

[0050] The concave spherical surface (4) of the second hole (3) forms a common spatial base for the placement of the hooks (5), and the uniform distribution of the hooks (5) along the circumference ensures the distribution of the circumferential component of the force between several contact zones. In this case, the end sections (6) of the hooks (5) absorb the force by the specified working support surfaces, and the inclined surfaces, conjugated with the concave spherical surface (4) of the second hole (3), reduce the abruptness of the transition to the specified working support surfaces. Due to this, the contact force is not concentrated predominantly in the edge sections of the profile, but is distributed between the consistently located working zones of the hooks (5).

[0051] The ratio of the height h of each hook (5) to the diameter D of the second hole (3) along the outer edge further limits the protrusion of the hooks (5) relative to the working area of ​​the second hole (3). This protrusion is sufficient to support the tightening torque and, at the same time, does not lead to excessive localization of contact at the tips or edges of the hooks (5). As a result, the combined implementation of these features reduces the calculated contact pressure in the interaction zone of the device with the drive sections of the vandal-resistant joint, which corresponds to a reduction in the specific contact load when transmitting a given tightening torque.

[0052] Examples of using the utility model

[0053] Example 1.

[0054] A device for mounting vandal-proof fasteners with M30 threads was manufactured to install vandal-proof fasteners when attaching a protective casing to a power transmission line support.

[0055] The device's cylindrical body is made of grade 40X steel according to GOST 4543-2013, followed by heat treatment to a hardness of 46 HRC. The body length is 75 mm, and the outer diameter is 68 mm.

[0056] A first hole with a square cross-section measuring 20 x 20 mm and a depth of 24 mm was drilled at one end of the housing. This first hole was designed to accommodate the head of an impact wrench. A second hole, bounded by a concave spherical surface, was drilled at the opposite end of the housing. The diameter D of this second hole along the outer edge was made equal to 58.02 mm. The first and second holes were aligned with each other.

[0057] Eight hooks, evenly spaced around the circumference, were machined onto the concave spherical surface of the second hole. Each hook had a flat end section perpendicular to the longitudinal axis of the housing and an inclined surface adjacent to the concave spherical surface of the second hole. The flat end section of each hook was positioned on the left side of the hook when viewed from the housing end with the second hole. The height h of each hook was set to 2.61 mm. With a diameter D of the second hole of 58.02 mm, the h / D ratio was 0.045.

[0058] The device was installed with the second hole on the drive portion of the vandal-resistant fastener and tightened using an impact wrench, the head of which was positioned in the first hole. When transmitting the tightening torque, the coaxial arrangement of the first and second holes ensured that the load was transferred to the working portion of the device without distortion, while eight evenly spaced hooks distributed the force across multiple contact zones. This design reduced the specific contact load on the drive portions of the vandal-resistant fastener when transmitting the specified tightening torque.

[0059] Example 2.

[0060] A vandal-resistant fastener installation tool was manufactured for installing M20 threaded fasteners during the assembly of metal playground elements. The tool was used to secure fencing panels to the supporting posts of the play structure.

[0061] The device's cylindrical body is made of 40KhFA steel according to GOST 4543-2013 with a hardness of 48 HRC. The body length is 65 mm, and the outer diameter is 49 mm.

[0062] A first hole with a square cross-section measuring 20 x 20 mm and a depth of 24 mm was drilled at one end of the housing. This first hole was designed to accommodate the head of an impact wrench. A second hole, bounded by a concave spherical surface, was drilled at the end of the housing opposite the first hole. The diameter D of this second hole along the outer edge was made equal to 39.01 mm. The first and second holes were aligned.

[0063] Six hooks, evenly spaced around the circumference, were machined onto the concave spherical surface of the second hole. Each hook had a flat end section perpendicular to the longitudinal axis of the housing and an inclined surface conjugated with the concave spherical surface of the second hole. The flat end section of each hook was positioned on the left side of the hook when viewed from the housing end with the second hole. The height h of each hook was set to 2.34 mm. With a diameter D of the second hole of 39.01 mm, the h / D ratio was 0.060.

[0064] The device was installed with the second hole on the drive portion of the vandal-resistant fastener and tightened using a wrench. When transmitting the tightening torque, the coaxial arrangement of the first and second holes ensured axial load transfer to the working portion of the device, while the hooks, evenly spaced around the circumference, distributed the force between the drive portions of the fastener. The hooks, with end sections, inclined surfaces, and an h / D ratio of 0.060, reduced the localization of the contact force and the specific contact load on the drive portions of the vandal-resistant fastener.

[0065] Example 3.

[0066] A vandal-resistant fastener installation tool with M12 threads was manufactured for installing a metal bench in a public area. The tool was used to secure the bench supports to the foundation elements in the park.

[0067] The device's cylindrical body is made of grade 40X steel according to GOST 4543-2013 with a hardness of 45 HRC. The body length is 50 mm, and the outer diameter is 33 mm.

[0068] A first hole with a square cross-section measuring 20 x 20 mm and a depth of 24 mm was drilled at one end of the housing. This first hole was designed to accommodate the head of an impact wrench. A second hole, bounded by a concave spherical surface, was drilled at the opposite end of the housing. The diameter D of this second hole along the outer edge was made equal to 23.07 mm. The first and second holes were aligned with each other.

[0069] Three hooks, evenly spaced around the circumference, were machined onto the concave spherical surface of the second hole. Each hook had a flat end section perpendicular to the longitudinal axis of the housing and an inclined surface adjacent to the concave spherical surface of the second hole. The flat end section of each hook was positioned on the left side of the hook when viewed from the housing end with the second hole. The height h of each hook was set to 1.22 mm. With a diameter D of the second hole of 23.07 mm, the h / D ratio was approximately 0.053.

[0070] The device was installed with the second hole on the drive portion of a vandal-resistant fastener and tightened using a nut runner. When transmitting the tightening torque, the hooks interacted with the drive portions of the fastener in a consistent, circumferential manner, while the inclined surfaces of the hooks reduced the likelihood of edge-concentration of the contact force. An h / D ratio of approximately 0.053 ensured sufficient hook protrusion to transmit torque without excessive contact localization, which resulted in a reduction in the specific contact load on the drive portions of the vandal-resistant fastener.

Claims

1. A device for mounting vandal-proof fasteners, comprising a housing (1) of cylindrical shape, at one end of which a first opening (2) is made, and at the opposite end of which a second opening (3) is made, limited by a concave spherical surface (4), on which hooks (5) are located, wherein each hook (5) comprises an end section (6) located perpendicular to the longitudinal axis of the housing (1), and an inclined surface conjugated with the concave spherical surface (4) of the second opening (3), characterized in that the height h of each hook (5) is from 0.045 to 0.060 of the diameter D of the second opening (3) along the outer edge.

2. The device according to item 1, characterized in that the first opening (2) and the second opening (3) are made coaxially with each other.

3. The device according to item 1, characterized in that the first hole (2) is made of a square cross-section with the possibility of placing the head of an impact wrench in it.

4. The device according to item 1, characterized in that on the inner surface of the second opening (3) there are from 3 to 10 hooks (5), evenly spaced around the circumference.

5. The device according to item 1, characterized in that the flat end section (6) of each hook (5) is located on the left side of the hook (5) when looking at the end of the body (1) with the second hole (3).

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