US20040083669A1

US20040083669A1 - Expansion joint cover

Info

Publication number: US20040083669A1
Application number: US10/288,912
Authority: US
Inventors: Johnnie Hilburn
Original assignee: Individual
Current assignee: Balco Inc
Priority date: 2002-11-05
Filing date: 2002-11-05
Publication date: 2004-05-06

Abstract

An expansion joint cover (10) broadly comprises a cover plate (38) to cover an expansion joint (12) between a first and second surface (14,16), an anchor assembly (40) to secure the plate (38) to the first surface (14), an insert (46) to protect the second surface (16), and one or more resilient bushings (48) to isolate the plate (38) from the anchor assembly (40). Under adverse conditions, such as during seismic events, the surfaces (14,16) may move significantly with respect to one another, thereby causing the plate (38) to slide over the second surface (16) and the insert (46) and deform the bushings (48). Thus, the flexibility of the plate (38), the durability of the insert (46), and the resilience of the bushings (48) all cooperate to allow the cover (10) to minimize stresses otherwise transferred to the anchor assembly (40).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to expansion joints and expansion joint covers. More particularly, the present invention relates to an expansion joint cover that can be installed over an expansion joint between a first surface and a second surface.

2. Description of Prior Art

Prior art expansion joint covers include cover plates covering expansion joints between first and second building surfaces. Typically, a first edge of the plate is coupled to the first surface and an opposed second edge is slidably received in a transition recess defined in the second surface. The second edge slides in the recess during relative movement of the surfaces caused by thermal expansion and contraction.

The second surface typically presents a beveled recess wall where the recess meets an adjacent upper surface of the second surface. During a seismic event, the joint may narrow such that the second edge of the plate slides over the recess wall onto the upper surface of the second surface. The recess wall is therefore subject to spalling, corrosion and potential impact damage from the second edge of the plate during a seismic event. Additionally, stresses involved with the plate sliding onto the upper surface are typically transferred to bolts anchoring the plate, thereby inducing shock and shear forces capable of damaging the bolts.

Furthermore, since the plate and the bolts may be constructed of dissimilar metals, electrolysis may lead to galvanic corrosion of either the plate, the bolts, or both. Additionally, the movement described above can be quite noisy.

Finally, prior art expansion joint systems are typically designed for installation during building construction. As a result, installation on an existing building as a retrofit can be expensive and labor intensive.

Accordingly, there is a need for an improved expansion joint cover that overcomes the limitations of the prior art.

SUMMARY OF THE INVENTION

The present invention overcomes the above-identified problems and provides a distinct advance in the art of expansion joint covers. More particularly, the present invention relates to an expansion joint cover that can be installed over an expansion joint between a first surface and a second surface. The cover broadly comprises a cover plate to cover the joint, an anchor assembly to secure the plate, a transition insert to protect the second surface, and one or more bushings to isolate the plate from the anchor assembly. The plate preferably presents a first edge positioned adjacent the first surface and a second edge positioned adjacent the second surface.

The anchor assembly preferably includes one or more concrete anchor members each inserted into a hole in the first surface and one or more bolts each threaded into one of the concrete anchor members. The insert protects the second surface from impact damage by the second edge of the plate during a seismic event.

Each bushing is preferably made of polyurethane or another resilient material, such as cork, rubber, or other flexible elastomer, and comprises a circular face positioned between the plate and the head of one of the bolts and a cylindrical sleeve positioned between the plate and the shank of one of the bolts. The sleeve preferably fits tightly between the shank and one of several penetrations in the plate, thereby securely holding the plate in position relative to the bolts.

Under normal conditions, such as during thermal expansion and contraction, the surfaces may move slightly with respect to one another. In this case, the plate slides over the second surface with minimal deformation of the plate and the bushings. Under adverse conditions, such as during seismic events, the building surfaces may move significantly with respect to one another. In this case, the plate slides over the second surface, may flex and slide over the insert, and may deform the bushings. Thus, the flexibility of the plate, the durability of the insert, and the resilience of the bushings all cooperate to allow the cover to minimize stresses otherwise transferred to the anchor assembly. Such stresses may otherwise shear the bolts, cause damage to the surfaces, or both.

Additionally, the bushings accommodate minor misalignment between the bolts and the penetrations in the plate. Such misalignment may occur during construction of the building, installation of the cover, or during the cover's service life. Without the bushings, the misalignment would otherwise induce stress on the anchor assembly leading to the damage described above.

Furthermore, the bushings prevent metal-to-metal contact between the plate and the bolts. Since the plate and the bolts may be constructed of dissimilar metals, electrolysis may otherwise lead to galvanic corrosion of either the plate, the bolts, or both. Additionally, the bushings minimize any noise associated with the movement described above. Finally, it can be seen that the bushings absorb any shock that may be associated with the movement described above, thereby reducing any such effects experienced by the anchor assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein: [0015]
FIG. 1 is a perspective view of an expansion [0016] joint cover 10 constructed in accordance with a preferred embodiment of the present invention and shown covering an expansion joint;
FIG. 2 is an elevation view of the cover; [0017]
FIG. 3 is a plan view of a bushing of the cover; and [0018]
FIG. 4 is an elevation view of the bushing.[0019]

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIG. 1, an [0020] expansion joint cover 10 is shown constructed in accordance with a preferred embodiment of the present invention. The cover 10 is used to cover an expansion joint 12 between a first building surface 14 and a second building surface 16 of a building such as a parking garage. Such building surfaces 14, 16 are typically composed of concrete. However, the surfaces 14,16 can have similar or different configurations and textures and may be parallel, perpendicular, or otherwise situated relative to each other.
Referring also to FIG. 2, the [0021] first surface 14 preferably presents a first upper surface 18 and a mounting recess 20 preferably having a depth of approximately three quarters of an inch adjacent the joint 12. The mounting recess 20 preferably presents a first support surface 22 and a first recess wall 24 between the first upper surface 18 and the first support surface 22.
Similarly, the [0022] second surface 16 preferably presents a second upper surface 28 and a transition recess 30 preferably having a depth of about three quarters of an inch adjacent the joint 12. The transition recess 30 preferably presents a second support surface 32 and a second recess wall 34 between the second upper surface 28 and the second support surface 32. The support surfaces 22,32 are preferably substantially aligned, such that they are planar, in order to allow the cover 10 to effectively cover the joint 12.
Either [0023] recess 20,30 may be pre-existing in the corresponding building surfaces 14,16 or may be cut into the building surfaces 14,16, in order to accommodate the cover 10. Alternatively, the cover 10 may be installed on the building surfaces 14,16 without either one or both of the recesses 20,30. However, this typically requires the cover 10 to protrude well beyond the building surfaces 14,16, and therefore may not be desired.
The [0024] cover 10 broadly comprises a cover plate 38 to cover the joint 12, an anchor assembly 40 to secure the plate 38, a first and second support pad 42,44 to support the plate 38, a transition insert 46 to protect the second building surface 16, and one or more bushings 48 to isolate the plate 38 from the anchor assembly 40. The plate 38 is preferably composed of approximately three eighths of an inch thick bent aluminum plate to present an approximately one half inch arch for increased structural strength, as illustrated in FIG. 2. The plate 38 extends along the joint's 12 length and is wide enough to span the joint 12. Therefore, the plate's 38 length and width are dependent upon dimensions of the joint 12. The plate 38 preferably presents a first edge 50 positioned in the mounting recess 20 and a second edge 52 positioned in the transition recess 30. Either edge 50,52 may be beveled in order to avoid presenting sharp corners.
The [0025] anchor assembly 40 preferably includes one or more concrete anchor members 54 each inserted into a hole in the first building surface 14 and one or more bolts 56 each threaded into one of the concrete anchor members 54. Each concrete anchor member 54 is preferably conventional and constructed of plastic. Each bolt 56 preferably includes a bolt head 58, a threaded end, and a shank 62 therebetween. The head 58 preferably resides external to the plate 38 and holds the plate 38 adjacent the joint 12. The threaded end preferably mates with the concrete anchor member 45 and holds the bolt 56 in place. The shank 62 preferably extends through one of several penetrations in the plate 38 adjacent the first edge 50 and through the first pad 42 and the bushing 48.
Alternatively, the [0026] anchor assembly 40 may include one or more bolts 56 cast directly into the concrete making up the first building surface 14. In this case, the anchor assembly 40 may also include a nut threaded onto each bolt 56 to secure the plate 38 over the joint 12.
The [0027] pads 42,44, are preferably approximately three eighths of an inch thick and preferably composed of a resilient, synthetic material, such as neoprene. The first pad 42 is preferably positioned in the mounting recess 20 between the first edge 50 of the plate 38 and the first support surface 22 and between the joint 12 and the first recess wall 24. The first pad 42 supports the first edge 50 of the plate 38 and allows the plate 38 to flex and move relative to the first building surface 14.
Similarly, the [0028] second pad 44 is preferably positioned in the transition recess 30 between the second edge 52 of the plate 38 and the second support surface 32 and between the joint 12 and the second recess wall 34. The second pad 44 supports the second edge 52 of the plate 38 and allows the second edge 52 to slide thereon during relative movement between the building surfaces 14,16.
The [0029] insert 46 is preferably integrally formed of metal, such as steel, aluminum, synthetic resin material, fiberglass, or a composite material. Such materials are chosen as needed to withstand expected loads of a particular installation. The insert 46 is preferably positioned in the transition recess 30 on the second support surface 32 and against the second recess wall 34. The insert 46 is preferably beveled in order to avoid presenting sharp corners and in order to present a smooth transition wall 64 between the second support surface 32 and the second upper surface 28. In particular, the transition wall 64 provides a transition between an upper face 66 of the second pad 44 and the second upper surface 28.
In the preferred embodiment, the [0030] transition recess 30 is wide enough so that the second edge 52 remains therein supported by the second pad 44 during expected widening and narrowing of the joint 12 due to thermal expansion and contraction. However, during a seismic event, the building surfaces 14,16 may move toward one another so that the second edge 52 slides over the transition wall 64 and onto the second upper surface 28. During such movement, the transition wall 64 guides the second edge 52 between the upper face 66 of the second pad 44 and the second upper surface 28.
The [0031] insert 46 is preferably constructed of materials less subject to spalling and corrosion than the concrete making up the second recess wall 34. Because of this, the insert 46 ensures reliable operation of the cover 10 for many years. Moreover, the insert 46 protects the second recess wall 34 from impact damage by the second edge 52 during a seismic event.
Referring also to FIGS. 3 and 4, each [0032] bushing 48 is preferably made of polyurethane or another resilient material, such as cork, rubber, or other flexible elastomer, and comprises a circular face 68 positioned between the plate 38 and the head 58 of one of the bolts 56 and a cylindrical sleeve 70 positioned between the plate 38 and the shank 62 of one of the bolts 56. The face 68 is preferably approximately one and one half inches in diameter and approximately three sixteenths of an inch thick. The sleeve 70 preferably includes an approximately one half inch internal diameter 72 that tightly fits around the shank 62, an approximately three quarters of an inch external diameter 74 that tightly fits within one of the penetrations in the plate 38, and an approximately three eighths of an inch length allowing the sleeve 70 to substantially completely penetrate the plate 38. Thus, the bushings 48 securely hold the plate 38 in position relative to the bolts 56, which are secured to the first building surface 14.
Under normal conditions, such as during thermal expansion and contraction, the building surfaces [0033] 14,16 may move slightly with respect to one another. In this case, the plate 38 slides over the second pad 44 with minimal deformation of the plate 38, the pads 42,44, and the bushings 48. Under adverse conditions, such as during seismic events, the building surfaces 14,16 may move significantly with respect to one another. In this case, the plate 38 slides over the second pad 44, may deform either of the pads 42,44 and the bushings 48, and may flex and slide over the transition wall 64 of the insert 46. Thus, the flexibility of the plate 38, the resilience of the pads 42,44 and the bushings 48, and the durability of the insert 46 all cooperate to allow the cover 10 to minimize stresses otherwise transferred to the anchor assembly 40. Such stresses may otherwise shear the bolts 56, cause damage to the building surfaces 14,16, or both.
Additionally, the [0034] bushings 48 accommodate minor misalignment between the bolts 56 and the penetrations in the plate 38. Such misalignment may occur during construction of the building, installation of the cover 10, or during the cover's 10 service life. Without the bushings 48, the misalignment would otherwise induce stress on the anchor assembly 40 leading to the damage described above.
Furthermore, the [0035] bushings 48 prevent metal-to-metal contact between the plate 38 and the bolts 56. Since the plate 38 and the bolts 56 maybe constructed of dissimilar metals, electrolysis may otherwise lead to galvanic corrosion of either the plate 38, the bolts 56, or both. Additionally, the bushings 48 minimize any noise associated with the movement described above. Finally, it can be seen that the bushings 48 absorb any shock that may be associated with the movement described above, thereby reducing any such effects experienced by the anchor assembly 40.
While the present invention has been described above, it is understood that other materials and/or dimensions can be substituted. For example, the [0036] face 68 of the bushings 48 maybe between one inch and two inches in diameter, and between one sixteenth of an inch and one half inch thick; but, are preferably sized to be wider than the head 58 of the bolts 56. The bushings 48 may resemble a grommet and comprise two faces 68 each disposed at opposing ends of the sleeve 70. In this case, the faces 68 may have diameters that differ from one another. Additionally, the internal diameter 72 of the sleeve 70 may be between one quarter inch and three quarter inches; but, is largely dependent upon the diameter of the shank 62 of the bolts 56. Furthermore, the external diameter 74 of the sleeve 70 maybe between one half inch and one inch; but, is largely dependent upon the diameter of the penetrations in the plate 38. Finally, the length of the sleeve 70 may be between one quarter inch and one half inch; but, is largely dependent upon the thickness of the plate 38. In this manner, the dimensions of the bushings 48 may be chosen to accommodate the dimensions of the plate 38 and the bolts 56. These and other minor modifications are within the scope of the present invention.

Claims

Having thus described a preferred embodiment of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following:

1. An expansion joint cover operable to cover an expansion joint between a first surface and a second surface, the cover comprising:

a cover plate operable to span the joint;

an anchor operable to penetrate the plate, thereby securing the plate to the first surface; and

a bushing between and operable to physically isolate the plate and the anchor.

2. The cover as set forth in claim 1, wherein the bushing is resilient and thereby further operable to allow the plate to move with respect to the anchor allowing the cover to accommodate movement between the surfaces.

3. The cover as set forth in claim 1, wherein the anchor is secured directly into the first surface.

4. The cover as set forth in claim 1, wherein the anchor includes a concrete anchor member disposed within a hole in the first surface and a fastener threaded into the concrete anchor member.

5. The cover as set forth in claim 1, wherein the bushing includes a circular face and a cylindrical sleeve.

6. The cover as set forth in claim 5, wherein the face is approximately one and one half inches in diameter and approximately three sixteenths of an inch thick.

7. The cover as set forth in claim 5, wherein the sleeve has an approximately one half inch internal diameter that tightly fits around at least a portion of the anchor.

8. The cover as set forth in claim 5, wherein the 1 sleeve has an approximately three quarters of an inch external diameter that tightly fits within a penetration in the plate.

9. The cover as set forth in claim 5, wherein the sleeve has an approximately three eighths of an inch length allowing the sleeve to substantially completely penetrate the plate.

10. An expansion joint cover operable to cover an expansion joint between a first surface and a second surface, the cover comprising:

a cover plate operable to span the joint;

an anchor secured directly into the first surface and operable to penetrate the plate, thereby securing the plate to the first surface; and

a resilient bushing between and operable to physically isolate the plate and the anchor, thereby operable to allow the plate to move with respect to the anchor allowing the cover to accommodate movement between the surfaces.

11. The cover as set forth in claim 10, wherein the anchor includes a concrete anchor member disposed within a hole in the first surface and a fastener threaded into the concrete anchor member.

12. The cover as set forth in claim 10, wherein the bushing includes a circular face and a cylindrical sleeve.

13. The cover as set forth in claim 12, wherein the face is approximately one and one half inches in diameter and approximately three sixteenths of an inch thick.

14. The cover as set forth in claim 12, wherein the sleeve has an approximately one half inch internal diameter that tightly fits around at least a portion of the anchor.

15. The cover as set forth in claim 12, wherein the sleeve has an approximately three quarters of an inch external diameter that tightly fits within a penetration in the plate.

16. The cover as set forth in claim 12, wherein the sleeve has an approximately three eighths of an inch length allowing the sleeve to substantially completely penetrate the plate.

17. An expansion joint cover operable to cover an expansion joint between a first surface and a second surface, the cover comprising:

a cover plate operable to span the joint;

an anchor assembly including

a concrete anchor member disposed within a hole in the first surface, and

a fastener threaded into the concrete anchor member and operable to penetrate the plate, thereby securing the plate to the first surface; and

a flexible bushing between and operable to physically isolate the plate and the anchor, the bushing including

a circular face approximately one and one half inches in diameter and approximately three sixteenths of an inch thick, and

a cylindrical sleeve with an approximately one half inch internal diameter that tightly fits around the fastener, an approximately three quarter inch external diameter that tightly fits within a penetration in the plate, and an approximately three eighths of an inch length allowing the sleeve to substantially completely penetrate the plate.