The present disclosure relates to brackets for crossarms, for example for securing crossarms to utility pole structures.
A crossarm bracket provides a structural interface between a crossarm and a pole structure, thereby enabling the transfer of loads from conductors/insulators though the crossarm and into the pole structure. The bracket should handle both the loads and ranges of deflections present in the crossarm as well as be able to properly transfer the loads to the pole structure without excessive local deformation or stress to the pole or the crossarm.
In order to transfer the loads and interface with metallic hardware for bolting and securement of the crossarm to the pole, the bracket is traditionally composed of steel that is coated or treated for corrosion resistance. Other materials may be used if their strength and stiffness are comparable to those of a steel bracket.
Due to the mounting of the crossarm on one side of the pole structure and the location of the conductors away from the pole and toward outboard ends of the crossarm, moments are created when loading is introduced from the conductors into the pole interface through attachment points to the structures. These load paths and structural connection points should be taken into account in the design of an efficient and robust crossarm bracket. The bracket typically comprises an interface for securing to the crossarm and an interface for securing to the pole.
Limitations of existing brackets include strength limitations, weld failures, excessive deflection, yielding failure under certain loading conditions, insufficient bearing interaction at connection points, and corrosion. The present disclosure seeks to provide improved crossarm brackets that address at least some of these shortcomings found in the prior art.
According to a first aspect of the disclosure, there is provided a bracket for securing a crossarm to a utility pole, comprising: a pole-mounting member for mounting to the utility pole by engaging a pole-receiving side of the pole-mounting member to the utility pole; a crossarm-mounting member secured to the pole-mounting member and comprising: a rear plate; and walls extending from the rear plate and away from the pole-receiving side of the pole-mounting member, wherein the rear plate and the walls define a channel for receiving the crossarm, and wherein the bracket further comprises at least one supporting member secured to the rear plate of the crossarm-mounting member and to the pole-mounting member, for resisting a load applied to the crossarm-mounting member when the crossarm is received within the channel.
The at least one supporting member may comprise: a first supporting member on a first side of a longitudinal axis defined by the pole-mounting member; and a second supporting member on a second side of the longitudinal axis, wherein the second side is opposite the first side.
The at least one supporting member may comprise: a plate portion secured to the rear plate of the crossarm-mounting member; and a pair of gusset portions extending from the plate portion and secured to the pole-mounting member.
The pair of gussets portions may meet the plate portion along respective curved edges.
The crossarm-mounting member may be welded to the pole-mounting member.
The pole-mounting member may comprise one or more mounting apertures at a top end thereof, for receiving one or more fasteners for mounting the pole-mounting member to the utility pole.
The one or more apertures may comprise at least one key-hole aperture.
The pole-mounting member may comprise a mounting recess at a bottom edge thereof, for mounting the pole-mounting member to the utility pole.
The mounting recess may extend from the bottom edge of the pole-mounting member upwards towards a top edge of the pole-mounting member.
The pole-mounting member has a generally frustoconical cross-sectional shape.
The pole-mounting member may comprise: a first plate portion; a pair of second plate portions angled relative to the first plate portion, extending from the first plate portion, and extending away from the crossarm-mounting member; and a pair of third plate portions angled relative to the second plate portions, extending from the second plate portions, and extending away from the crossarm-mounting member.
The at least one supporting member may be secured to one or more of the pair of second plate portions and the pair of third plate portions.
The at least one supporting member may be welded to one or more of the pair of second plate portions and the pair of third plate portions
The walls of the crossarm-mounting member may meet the rear plate of the crossarm-mounting member along respective curved edges.
The crossarm-mounting member may comprise apertures for receiving fasteners therethrough.
According to a further aspect of the disclosure, there is provided a bracket for securing a crossarm to a utility pole, comprising: a pole-mounting member for mounting to the utility pole by engaging a pole-receiving side of the pole-mounting member to the utility pole; a crossarm-mounting member welded to the pole-mounting member and comprising: a rear plate; and walls extending from the rear plate and away from the pole-receiving side of the pole-mounting member, wherein the rear plate and the walls define a channel for receiving the crossarm.
According to a further aspect of the disclosure, there is provided a bracket for securing a crossarm to a utility pole, comprising: a pole-mounting member for mounting to the utility pole by engaging a pole-receiving side of the pole-mounting member to the utility pole; a crossarm-mounting member secured to the pole-mounting member and comprising: a mounting plate for mounting the crossarm to the crossarm-mounting member; and walls extending from the mounting plate and toward the pole-receiving side of the pole-mounting member.
The walls may comprise upper walls and lower walls, and the upper walls and the lower walls may define a groove within which is received the pole-mounting member.
A cross-sectional shape of the pole-mounting member may substantially conform to a shape of the groove.
The crossarm-mounting member may comprise apertures for receiving fasteners therethrough.
The pole-mounting member may comprise one or more mounting apertures at a top end thereof, for receiving one or more fasteners for mounting the pole-mounting member to the utility pole.
The one or more apertures may comprise at least one key-hole aperture.
The bracket may further comprise a first reinforcing doubler secured to the pole-mounting member.
The first reinforcing doubler may comprise one or more doubler apertures formed therein.
A shape of the one or more doubler apertures may correspond to a shape of the one or more mounting apertures of the pole-mounting member.
The pole-mounting member may comprise a mounting recess at a bottom edge thereof, for mounting the pole-mounting member to the utility pole.
The mounting recess may extend from the bottom edge of the pole-mounting member upwards towards a top edge of the pole-mounting member.
The bracket may further comprise a second reinforcing doubler secured to the pole-mounting member.
The second reinforcing doubler may comprise a doubler recess formed therein.
A shape of the doubler recess may correspond to a shape of the mounting recess of the pole-mounting member.
The pole-mounting member may have a generally frustoconical cross-sectional shape.
The pole-mounting member may comprise: a first plate portion; a pair of second plate portions angled relative to the first plate portion, extending from the first plate portion, and extending away from the crossarm-mounting member; and a pair of third plate portions angled relative to the second plate portions, extending from the second plate portions, and extending away from the crossarm-mounting member.
The bracket may further comprise a support member secured to the pole-mounting member in a position for supporting the crossarm when the crossarm is mounted to the mounting plate.
The support member may comprise a plate portion and a pair of gusset portions extending from the plate portion and secured to the pole-mounting member.
The plate portion may meet the pair of gusset portions at respective curved edges.
The bracket may further comprise a guy-wire attachment for securing the bracket to a guy-wire.
The guy-wire attachment may comprise one or more tab members secured to an underside of at least one of the walls of the crossarm-mounting member and to the pole-mounting member.
The guy-wire attachment may comprise a first end secured relative to the crossarm-mounting member and a second end comprising one or more rotating members rotatable relative to the guy-wire attachment.
The guy-wire attachment may comprise a plate member secured to at least one of the walls of the crossarm-mounting member.
The bracket may further comprise a further plate member secured to at least another one of the walls of the crossarm-mounting member.
According to a further aspect of the disclosure, there is provided a bracket for securing a crossarm to a utility pole, comprising: a pole-mounting member comprising: a pole-receiving side, wherein the pole-mounting member is mountable to the utility pole by engaging the pole-receiving side to the utility pole; and a front surface on a front side of the pole-mounting member, wherein the front side is opposite the pole-receiving side; an upper plate secured to the front surface of the pole-mounting member and extending away from the pole-receiving side of the pole-mounting member; and a lower plate secured to the front surface of the pole-mounting member and extending away from the pole-receiving side of the pole-mounting member, wherein the upper plate includes a lower surface facing the lower plate, and the lower plate includes an upper surface facing the upper plate, and wherein the lower surface of the upper plate, the upper surface of the lower plate, and the front surface of the pole-mounting member define interconnected walls of a channel for receiving therein at least a portion of the crossarm.
The bracket may further comprise a supporting member secured to the lower plate and to the front surface of the pole-mounting member, for resisting a load applied to the lower plate when the crossarm is received within the channel.
The supporting member may further comprise one or more apertures formed therein for attaching a guy-wire to the supporting member.
The supporting member may extend perpendicularly to the lower plate.
One or both of the upper plate and the lower plate may be welded to the front surface of the pole-mounting member.
The pole-mounting member may comprise one or more mounting apertures at a top end thereof, for receiving one or more fasteners for mounting the pole-mounting member to the utility pole.
The one or more apertures may comprise at least one key-hole aperture.
The pole-mounting member may comprise a mounting recess at a bottom edge thereof, for mounting the pole-mounting member to the utility pole.
The mounting recess may extend from the bottom edge of the pole-mounting member upwards towards a top edge of the pole-mounting member.
The pole-mounting member may have a generally frustoconical cross-sectional shape.
Each of the upper plate and the lower plate may be secured across an entirety of a width of the front surface of the pole-mounting member.
The pole-mounting member may comprise: a first plate portion defining the front surface of the pole-mounting member; a pair of second plate portions angled relative to the first plate portion, and extending from the first plate portion and away from the upper plate and the lower plate; and a pair of third plate portions angled relative to the second plate portions, and extending from the second plate portions and away from the upper plate and the lower plate.
Each of the upper plate and the lower plate may be secured across an entirety of a width of the first plate portion.
Each of the upper plate and the lower plate may be further secured to at least a portion of each of the second plate portions.
Each of the upper plate and the lower plate may be welded to the at least a portion of each of the second plate portions.
The upper plate and the lower plate may extend perpendicularly to the pole-mounting member.
Each of the upper plate and the lower plate may comprise apertures for receiving fasteners therethrough, for securing the crossarm to the upper plate and the lower plate when the crossarm is received within the channel.
Each of the upper plate and the lower plate may comprise a front edge, side edges extending from the front edge and toward the pole-receiving side of the pole-mounting member, and a pair of rear edges extending at obtuse angles to the side edges and toward the pole-receiving side of the pole-mounting member.
This summary does not necessarily describe the entire scope of all aspects. Other aspects, features and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.
Embodiments of the disclosure will now be described in detail in conjunction with the accompanying drawings of which:
The present disclosure seeks to provide improved brackets for crossarms. While various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims.
Generally, according to embodiments of the disclosure, there are described brackets for supporting loads exerted on crossarms by conductors, guy wires, and other external sources. Under certain loading conditions, existing metallic brackets are susceptible to failure by cracking at weld lines or yielding. Brackets according to embodiments described herein may address potential weak points of existing brackets by providing assemblies that in use are less likely to experience yielding or cracking. For example, by optimizing the thickness, weld locations, and design elements to be more structurally efficient, adequate strength and stiffness may be provided for handling symmetric or asymmetric loading. Furthermore, the design may benefit from improved performance in actual field operations and over the life of the structure. This may ensure that brackets according to embodiments described herein may be reliable and resilient against actual field conditions throughout the service life of the bracket, and may minimize the risk of any potential failures or power outages that might result from improper bracket performance.
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Deadend bracket 10 comprises a vertically-oriented pole-mounting member 24, and a horizontally-oriented crossarm-mounting member 14 secured to pole-mounting member 24. It will be understood that the terms “vertically-oriented” and “horizontally-oriented” are relative terms, and are used to described the respective orientations of pole-mounting member 24 and crossarm-mounting member 14 relative to a vertically-oriented utility pole (not shown). It shall therefore be understood that, in other contexts, pole-mounting member 24 need not be vertically oriented, and crossarm-mounting member 14 need not be horizontally oriented.
Pole-mounting member 24 includes a pole-receiving side and a crossarm-receiving side opposite the pole-receiving side. Pole-mounting member 24 is used to mount deadend bracket 10 to a utility pole by engaging the pole-receiving side of pole-mounting member 24 to the utility pole, as described in further detail below. Pole-mounting member 24 enables deadend bracket 10 to interface with the utility pole and transfer the load applied by the crossarm over a relatively large area, while securing deadend bracket 10 to the utility pole. As described in further detail below, pole-mounting member 24 is shaped to conform to the round shape of utility pole tops, with a tapered flange design that enables deadend bracket 10 to mate to a range of pole diameters and make contact with the utility pole along the vertical length of pole-mounting member 24.
When viewed along a horizontal cross-section, pole-mounting member 24 has a generally frustoconical shape. In particular, pole-mounting member 24 includes a first plate portion 11, a pair of second plate portions 12, and a pair of third plate portions 13. Second plate portions 12 are angled relative to first plate portion 11, and extend away from crossarm-mounting member 14. Third plate portions 13 are angled relative to second plate portions 12 and extend away from crossarm-mounting member 14. Second plate portions 12 are angled relative to first plate portion 11 such that the obtuse angles formed therebetween are located on the pole-receiving side of pole-mounting member 24. Third plate portions 13 are angled relative to second plate portion 12 such that the obtuse angles formed therebetween are located on the crossarm-receiving side of pole-mounting member 24. This angling may result in a relatively smooth radius on the pole-receiving side at the interface of second plate portions 12 and third plate portions 13. This may ensure that little or no gouging of the underlying pole will occur, which may be important for ensuring structural integrity of the pole.
Pole-mounting member 24 includes a number of mounting apertures for mounting deadend bracket 10 to the utility pole. In particular, at an upper end of pole-mounting member 24, there is provided a key-hole aperture 15. At a bottom end of pole-mounting member 24, there is provided a mounting recess 20, forming a slot feature, extending from a bottom edge 21 of pole-mounting member 24 upwards towards a top edge of pole-mounting member 24. In order to mount deadend bracket 10 to a utility pole, key-hole aperture 15 and mounting recess 20 are aligned with and receive corresponding fasteners provided on the utility pole. Deadend bracket 10 is then translated downwardly until the fasteners engage with key-hole aperture 15 and mounting recess 20, at which point the fasteners are tightened to the recommended torque to ensure they will not loosen over time, thereby securing deadend bracket 10 to the utility pole.
Crossarm-mounting member 14 comprises a rear plate 19 and upper and lower walls 17a, 17b extending perpendicularly from rear plate 19 and away from the pole-receiving side of pole-mounting member 24. The edges 18a, 18b along which rear plate 19 meets with upper and lower walls 17a, 17b are curved (by being formed to conform to a crossarm profile) in order to assist with load distribution when the crossarm is secured to crossarm-mounting member 14. Crossarm-mounting member 14 is secured to pole-mounting member 24 by welding crossarm-mounting member 14 to pole-mounting member 24 at example weld locations 29 along first plate portion 11 and edges 18a, 18b, as seen
As can be seen in
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In particular, deadend bracket 30 includes a first supporting doubler 48a on a left-hand side of a longitudinal axis L of pole-mounting member 44, and a second supporting doubler 48b on a right-hand side of longitudinal axis L. Each supporting member 48a, 48b includes a plate portion 47 secured by welding to rear plate 39 of crossarm-mounting member 34. Each supporting member 48a, 48b further includes a pair of triangular-shaped gusset portions 44 extending from plate portion 47 and secured to pole-mounting member 44. In particular, each gusset portion 44 is secured by welding to a second plate portion 32 and a third plate portion 33 of pole-mounting member 44. Example weld locations 49 can be seen in
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Tangent bracket 60 is similar to deadend bracket 10, and similar features are therefore labelled using similar reference numbers. However, unlike crossarm-mounting member 14 of deadend bracket 10, crossarm-mounting member 64 of tangent bracket 60 comprises a mounting plate 69, pair of spaced-apart upper walls 67a extending from mounting plate 69, and a pair of spaced-apart lower walls 67b extending from mounting plate 69. Upper walls 67a and lower walls 67b therefore define a groove extending in a vertical direction centrally relative to ends of crossarm-mounting member 64. Pole-mounting member 74 is received within the groove and secured to crossarm-mounting member 64 by welding, as can be seen by the example weld locations 79 in
In order to secure the crossarm to tangent bracket 60, mounting holes 66 are provided within mounting plate 69 of crossarm-mounting member 64. The crossarm is then secured to mounting plate 69 using fasteners such as bolts, reinforced by flat washers and nuts on the opposing side of the crossarm, to secure tightly the crossarm to bracket 60. Multiple mounting holes 66 enable the load to be spread over multiple fasteners to constrain a relatively larger area of the crossarm to tangent bracket 60, thereby minimizing deflection of the crossarm. Mounting holes 66 are aligned in the plane of the conductors in the tangent application to primarily react to transverse and vertical crossarm loads. In use, the C-shaped channel 62 defined by mounting plate 69, upper walls 67a, and lower walls 67b may help further resist deflection and yielding of tangent bracket 60.
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The support member comprises a plate portion 97 and a pair of triangular gusset portions 95 extending from plate portion 97 and secured to pole-mounting member 94. The pair of gussets portions 95 meet plate portion 97 along respective curved edges 96. Plate portion 97 is welded to first plate portion 81 of pole-mounting member 94, immediately beneath mounting plate 89, and gusset portions 95 are welded to second plate portions 82 of pole-mounting member 94. Example weld locations 95 are shown in
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As can also be seen in
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While brackets according to embodiments of the disclosure have been described as comprising one or more components welded to one another, it shall be understood that according to some embodiments the components may be fastened or secured to one another using other means. For example, instead of securing the crossarm-mounting member to the pole-mounting member by welding, the crossarm-mounting member may be secured to the pole-mounting member using bolts or other fasteners.
According to embodiments of the disclosure, the brackets described herein may be constructed of a suitably strong material, such as steel, although the disclosure extends to any other suitable material, such as aluminium or a lightweight material with suitable strength and stiffness to impart a similar response as a steel bracket, provided that substantially equivalent strength and stiffness can be achieved to support the loading present in utility applications.
Typically, with cold-rolled steel construction, the potential for corrosion exists, and steel hardware is typically coated, plated, or galvanized to avoid corrosion. According to some embodiments, brackets as described herein may comprise steel with a hot-dip galvanizing layer to be added secondarily to minimize the potential for corrosion over the service life of the bracket. Similarly, utility grade fasteners and related hardware (washers, nuts, etc.) may also comprise hot-dipped galvanized steel. Alternative fasteners may be made of other suitable corrosion-resistant materials.
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In
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Deadend bracket 200 comprises a vertically-oriented pole-mounting member 224, and a pair of horizontally-oriented crossarm-mounting members secured to pole-mounting member 24. In particular, the crossarm-mounting members comprise an upper plate 217a and an opposed lower plate 217b. It will be understood that the terms “vertically-oriented” and “horizontally-oriented” are relative terms, and are used to described the respective orientations of pole-mounting member 224 and upper and lower plates 217a, 217b relative to a vertically-oriented utility pole (not shown). It shall therefore be understood that, in other contexts, pole-mounting member 224 need not be vertically oriented, and upper and lower plates 217a, 217b need not be horizontally oriented.
Pole-mounting member 224 includes a pole-receiving side and a crossarm-receiving side opposite the pole-receiving side. Pole-mounting member 224 is used to mount deadend bracket 200 to a utility pole by engaging the pole-receiving side of pole-mounting member 224 to the utility pole. Pole-mounting member 224 enables deadend bracket 200 to interface with the utility pole and transfer the load applied by the crossarm over a relatively large area, while securing deadend bracket 200 to the utility pole. As described in further detail below, pole-mounting member 224 is shaped to conform to the round shape of utility pole tops, with a tapered flange design that enables deadend bracket 200 to mate to a range of pole diameters and make contact with the utility pole along the vertical length of pole-mounting member 224.
When viewed along a horizontal cross-section, pole-mounting member 224 has a generally frustoconical shape. In particular, pole-mounting member 224 includes a first plate portion 211, a pair of second plate portions 212, and a pair of third plate portions 213. Second plate portions 212 are angled relative to first plate portion 211, and extend away from upper and lower plates 217a, 217b. Third plate portions 213 are angled relative to second plate portions 212 and extend away from upper and lower plates 217a, 217b. Second plate portions 212 are angled relative to first plate portion 211 such that the obtuse angles formed therebetween are located on the pole-receiving side of pole-mounting member 224. Third plate portions 213 are angled relative to second plate portion 212 such that the obtuse angles formed therebetween are located on the crossarm-receiving side of pole-mounting member 224. This angling may result in a relatively smooth radius on the pole-receiving side at the interface of second plate portions 212 and third plate portions 213. This may ensure that little or no gouging of the underlying pole will occur, which may be important for ensuring structural integrity of the pole.
Pole-mounting member 224 includes a number of mounting apertures for mounting deadend bracket 200 to the utility pole. In particular, at an upper end of pole-mounting member 224, there is provided a key-hole aperture 215. At a bottom end of pole-mounting member 224, there is provided a mounting recess 220, forming a slot feature, extending from a bottom edge 221 of pole-mounting member 224 upwards towards a top edge of pole-mounting member 224. In order to mount deadend bracket 200 to a utility pole, key-hole aperture 215 and mounting recess 220 are aligned with and receive corresponding fasteners provided on the utility pole. Deadend bracket 200 is then translated downwardly until the fasteners engage with key-hole aperture 215 and mounting recess 220, at which point the fasteners are tightened to the recommended torque to ensure they will not loosen over time, thereby securing deadend bracket 200 to the utility pole.
Upper and lower plates 217a, 217b extend perpendicularly away from the pole-receiving side of pole-mounting member 224. Upper and lower plates 217a, 217b are secured to pole-mounting member 224 by welding upper and lower plates 217a, 217b across the entire width of first plate portion 211. As can be seen in
As can be seen in
In particular, in order to assist in dealing with such application, deadend bracket 500 includes a supporting member 550 having apertures 555 formed therein for attaching a guy-wire to supporting member 550. Supporting member 550 is vertically oriented and secured (e.g. by welding) to the underside of lower plate 517b and first plate portion 511. As discussed above, the line termination loads of a crossarm supported in the deadend bracket may be transferred to the ground by guying with a guy-wire placed at an angle from supporting member 550 to the ground and secured with a ground anchor tied to the guy-wire.
In addition to supporting member 550, upper and lower plates 517a, 517b are secured (e.g. welded) across an entirety of a width of first plate portion 511 and to a portion of each of second plate portions 512. In addition, compared to deadend bracket 200, upper edges of upper and lower plates 517a, 517b form relatively larger obtuse angles relative of the side edges of upper and lower plates 517a, 517b, to thereby provide more room for welding upper and lower plates 517a, 517b to second plate portions 512.
The word “a” or “an” when used in conjunction with the term “comprising” or “including” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise.
The terms “coupled”, “coupling” or “connected” as used herein can have several different meanings depending on the context in which these terms are used. For example, as used herein, the terms coupled, coupling, or connected can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via a mechanical element depending on the particular context. The term “and/or” herein when used in association with a list of items means any one or more of the items comprising that list.
As used herein, a reference to “about” or “approximately” a number or to being “substantially” equal to a number means being within +/−10% of that number.
While the disclosure has been described in connection with specific embodiments, it is to be understood that the disclosure is not limited to these embodiments, and that alterations, modifications, and variations of these embodiments may be carried out by the skilled person without departing from the scope of the disclosure.
It is furthermore contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2022/051387 | 9/20/2022 | WO |
Number | Date | Country | |
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63247168 | Sep 2021 | US | |
63314555 | Feb 2022 | US |