MANHOLE COVER LIFTER

Abstract

A manhole cover lifting tool includes an elongated bar. A pivoting L-hook and a fixed J-hook are attached at one end of the bar. A pivoting support base is attached between the ends of the bar. The support base includes a pair of legs extending from a base assembly. The base assembly includes a first plate, a second plate and a turntable bearing disposed between the first plate and the second plate. A cap fitting threadedly engages an end of the bar. A cleanout tool extends from the cap fitting into a hollow interior of the bar. A light source is attached near an end of the bar. A handle assembly is clamped to the bar between the support assembly and end.

Claims

1. A manhole cover lifting tool comprising: an elongated bar having a first end and an opposite second end; a pivoting hook attached at the first end of the bar; a pivoting support base attached between the first end of the bar and the second end of the bar, wherein the support base includes a pair of legs extending from a base assembly, and the elongated bar is pivotally attached to the pair of legs, and the base assembly includes a first plate, a second plate and a turntable bearing disposed between the first plate and the second plate, the turntable bearing enabling rotation of the first plate relative to the second plate, and the pair of legs are attached to the first plate.

2. The manhole cover lifting tool according to claim 1, further comprising a J-shaped hook fixed to the first end of the bar.

3. The manhole cover lifting tool of claim 1, wherein the elongated bar is hollow, and the second end includes external threads, and the manhole cover lifting tool further comprises a cap fitting threadedly engaged to the second end, and a cleanout tool extends from the cap fitting into the hollow elongated bar.

4. The manhole cover lifting tool of claim 1, further comprising a light source attached to the bar adjacent to the first end.

5. The manhole cover lifting tool of claim 4, wherein the light source comprises a flashlight, and the manhole cover lifting tool further comprises at least one clamp attached to the bar, the at least one clamp securing the flashlight to the bar.

6. The manhole cover lifting tool of claim 1, the turntable bearing comprising a first bearing plate and a second bearing plate, an annular groove formed in each of the first bearing plate and the second bearing plate, the annular groove of the first bearing plate being aligned with and opposed to the annular groove of the second bearing plate, and the annular groove of the first bearing plate and the annular groove of the second bearing plate defining an annular passage, and a plurality of balls disposed in the annular passage between the first bearing plate and the second bearing plate.

7. The manhole cover lifting tool of claim 1, the pivoting hook comprising a pair of arms, the pair of arms attached to the bar at one end and attached to a 90-degree metal angle at an opposite end, the 90-degree metal angle being sized to engage a manhole cover.

8. The manhole cover lifting tool of claim 1, further comprising a handle assembly, the handle assembly including a handle and a pipe clamp attached to the handle, the pipe clamp securing the handle assembly to the bar between the support assembly and the second end, and the handle extending perpendicular to the bar.

9. The manhole cover lifting tool of claim 1, the bar comprising steel pipe with an inner diameter of at least 1-inch.

10. A manhole cover lifting tool comprising: an elongated bar having a first end and an opposite second end, wherein the elongated bar is hollow; a pivoting hook attached at the first end of the bar; a pivoting support base attached between the first end of the bar and the second end of the bar, wherein the support base includes a pair of legs extending from a base assembly, and the elongated bar is pivotally attached to the pair of legs, and the base assembly includes a first plate, a second plate and a turntable bearing disposed between the first plate and the second plate, the turntable bearing enabling rotation of the first plate relative to the second plate, and the pair of legs are attached to the first plate; and a J-shaped hook fixed to the first end of the bar.

11. The manhole cover lifting tool of claim 10, wherein the second end includes external threads, and the manhole cover lifting tool further comprises a cap fitting threadedly engaged to the second end, and a cleanout tool extends from the cap fitting into the hollow elongated bar.

12. The manhole cover lifting tool of claim 11, further comprising a light source attached to the bar adjacent to the first end.

13. The manhole cover lifting tool of claim 12, wherein the light source comprises a flashlight, and the manhole cover lifting tool further comprises at least one clamp attached to the bar, the at least one clamp securing the flashlight to the bar.

14. The manhole cover lifting tool of claim 10, the turntable bearing comprising a first bearing plate and a second bearing plate, an annular groove formed in each of the first bearing plate and the second bearing plate, the annular groove of the first bearing plate being aligned with and opposed to the annular groove of the second bearing plate, and the annular groove of the first bearing plate and the annular groove of the second bearing plate defining an annular passage, and a plurality of balls disposed in the annular passage between the first bearing plate and the second bearing plate.

15. The manhole cover lifting tool of claim 10, the pivoting hook comprising a pair of arms, the pair of arms attached to the bar at one end and attached to a 90-degree metal angle at an opposite end, the 90-degree metal angle being sized to engage a manhole cover.

16. The manhole cover lifting tool of claim 10, further comprising a handle assembly, the handle assembly including a handle and a pipe clamp attached to the handle, the pipe clamp securing the handle assembly to the bar between the support assembly and the second end, and the handle extending perpendicular to the bar.

17. The manhole cover lifting tool of claim 10, the bar comprising steel pipe with an inner diameter of at least 1-inch.

18. A manhole cover lifting tool comprising: an elongated bar having a first end and an opposite second end, wherein the elongated bar is a hollow pipe with an inner diameter of at least 1-inch; a pivoting hook attached at the first end of the bar, the pivoting hook comprising a pair of arms, the pair of arms attached to the bar at one end and attached to a 90-degree metal angle at an opposite end, the 90-degree metal angle being sized to engage a manhole cover; a pivoting support base attached between the first end of the bar and the second end of the bar, wherein the support base includes a pair of legs extending from a base assembly, and the elongated bar is pivotally attached to the pair of legs, and the base assembly includes a first plate, a second plate and a turntable bearing disposed between the first plate and the second plate, the turntable bearing enabling rotation of the first plate relative to the second plate, and the pair of legs are attached to the first plate, the turntable bearing comprising a first bearing plate and a second bearing plate, an annular groove formed in each of the first bearing plate and the second bearing plate, the annular groove of the first bearing plate being aligned with and opposed to the annular groove of the second bearing plate, and the annular groove of the first bearing plate and the annular groove of the second bearing plate defining an annular passage, and a plurality of balls disposed in the annular passage between the first bearing plate and the second bearing plate; and a J-shaped hook fixed to the first end of the bar; a handle assembly, the handle assembly including a handle and a pipe clamp attached to the handle, the pipe clamp securing the handle assembly to the bar between the support assembly and the second end, and the handle extending perpendicular to the bar.

19. The manhole cover lifting tool of claim 10, wherein the second end includes external threads, and the manhole cover lifting tool further comprises a cap fitting threadedly engaged to the second end, and a cleanout tool extends from the cap fitting into the hollow elongated bar.

20. The manhole cover lifting tool of claim 11, further comprising a light source attached to the bar adjacent to the first end.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing and other aspects, objects, features and advantages of the invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where:

[0018] FIG. 1 is a side view of an exemplary manhole cover lifting tool according to principles of the invention; and

[0019] FIG. 2 is a perspective view of an exemplary manhole cover lifting tool according to principles of the invention; and

[0020] FIG. 3 is a side view of an exemplary manhole cover lifting tool engaging a manhole cover according to principles of the invention; and

[0021] FIG. 4 is a perspective view of an exemplary manhole cover lifting tool engaging a manhole cover according to principles of the invention; and

[0022] FIG. 5 is a side view of an exemplary manhole cover lifting tool pivoting an engaged manhole cover according to principles of the invention; and

[0023] FIG. 6 is a perspective view of an exemplary manhole cover lifting tool pivoting an engaged manhole cover according to principles of the invention; and

[0024] FIG. 7 is a side exploded view of an exemplary manhole cover lifting tool according to principles of the invention; and

[0025] FIG. 8 is a perspective exploded view of an exemplary manhole cover lifting tool according to principles of the invention; and

[0026] FIG. 9 is a perspective exploded view of an exemplary compact swivel base for a manhole cover lifting tool according to principles of the invention; and

[0027] FIG. 10 is a partially exploded section view of an exemplary turntable bearing assembly for a manhole cover lifting tool according to principles of the invention.

[0028] Those skilled in the art will appreciate that the figures are not intended to be drawn to any particular scale; nor are the figures intended to illustrate every embodiment of the invention. The invention is not limited to the exemplary embodiments depicted in the figures or the specific components, configurations, shapes, relative sizes, ornamental aspects or proportions as shown in the figures.

DETAILED DESCRIPTION

[0029] An exemplary tool for lifting a manhole cover according to principles of the invention includes an elongated bar that provides mechanical advantage to unseat and remove a manhole cover. The exemplary tool is compact and easy to deploy, without any assembly. The exemplary tool includes both a cleaning implement and a light source. The exemplary tool is capable of pitching and yawing motion. The yawing motion is accomplished with a bearing assembly in a compact base to reduce the significant friction forces that a bulky manhole cover may otherwise cause.

[0030] FIGS. 1 and 2 conceptually illustrate an exemplary manhole cover lifting tool 100 according to principles of the invention. The tool 100 is an assembly that includes a bar 105. The bar 105 is elongated. It functions as a beam of a lever that pivots about a fulcrum, in this case a support assembly 150. In an exemplary embodiment, the bar 105 is a hollow galvanized steel pipe, approximately 42-inches in length from a trailing edge 185 to a leading edge 190. The length should be at least three feet. A length that is longer than 42-inches such as four or five feet may be used. Such longer lengths may be more difficult to store and carry. The diameter of the pipe is at least 1-inch (nominal inside diameter), with a larger diameter of 1.25 or 1.5 inch being more preferred for additional strength.

[0031] The trailing edge 185 of the bar 105 is threaded. A cap fitting 180 is threaded onto the trailing edge of the bar. The cap fitting 180 is a part of a cleanout tool, discussed below.

[0032] A support assembly 150 is attached to the bar at about the middle of the bar 150 (i.e., the middle between the leading edge 190 and trailing edge 185), or at a point between the leading edge 190 and the middle. The support assembly is attached a sufficient distance from the leading edge 190 to avoid interference with the L-hook 130 when the L-hook 130 is pivoted against the bar 105. Thus, the distance between the point of attachment of the support assembly 150 and the point of attachment of the L-hook 130 equals or exceeds the length of the L-hook 130.

[0033] The support assembly 150 serves several functions. First, it operates as a fulcrum about which the bar 105 pivots. Thus, the bar 105 and support assembly operate as a lever. Second, the support assembly provides swiveling capability.

[0034] The support assembly 150 includes a pair of legs 145 that extend from the bar 105 to a base 135. The upper ends of the legs 145 include aligned mounting holes. A nut (e.g., knob nut 155) engages a bolt that extends through the aligned holes in the legs and an aligned hole in the bar 105. When the nut 155 is sufficiently loose, the bar 105 may freely pivot about the bolt. When the nut 155 is tightened, pivoting motion is resisted. In this manner, the support assembly 150 may be deployed to an orientation that is generally perpendicular to the bar 105. The bar 105 may pivot, relative to the support assembly 150. During such pivoting, the angles between the support assembly and bar 105 will change. Additionally, for storage and transportation, the support assembly 150 may be pivoted against the bar 105 and the nut 155 may be tightened to secure the support assembly in that position.

[0035] The base 135 of the support assembly is a compact base 135 that swivels (i.e., yaws, or rotates about an axis, e.g., a vertical axis, that is orthogonal to the pivoting axis). The base is described in greater detail below. The base 135 is attached (e.g., welded) to the legs 145. The bottom of the base 135 contacts the ground when the tool is in use.

[0036] Two separate hooks are provided at (i.e., at or about, in the immediate vicinity of) the leading edge 190. One hook is an L-hook 130, which is an L shaped hook. The L-hook 130 is capable of pivoting motion relative to the bar 105. A primary function of the L-Hook 130 is to engage a manhole cover at an engagement feature while the manhole cover is unseated and removed.

[0037] The L-hook 130 includes a pair of arms 125 that extend from the bar 105 to a base 135. The upper ends of the arms 125 include aligned mounting holes. A nut (e.g., knob nut 110) engages a bolt that extends through the aligned holes in the arms and an aligned hole in the bar 105. When the nut 110 is sufficiently loose, the bar 105 may freely pivot about the bolt. When the nut 110 is tightened, pivoting motion is resisted. In this manner, the L-hook 130 may be allowed to freely swing, and deployed to an orientation that is generally vertical. The L-hook 130 may freely pivot, relative to the bar 105. During such pivoting, the angles between the L-hook 130 and bar 105 will change. Additionally, for storage and transportation, the L-hook 130 may be pivoted against the bar 105 and the nut 110 may be tightened to secure the support assembly in that position.

[0038] The arms 125 are shorter than the legs 145. The lengths of the arms 125 is between ? to ? of the lengths of the legs 145. This configuration allows a range of pivoting motion of the bar 105 without collapsing the L-hook 130.

[0039] The bottom of the L-hook 130 includes a L-shaped bend 120. The bend 120 may comprise a steel 90? angle attached (e.g., welded) to the legs 125. The bend is sized to engage an engagement feature (e.g., slot) of a manhole cover. The width of the bend 120 is not greater than the width of the engagement feature, to allow the bend 120 to fit into the engagement feature.

[0040] A fixed J-hook 115 is also provided at the leading edge 190 of the bar. The J-hook 115 is used to engage an unseated or removed manhole cover. The J hook may engage an edge of the cover or an engagement feature of the cover. A user may pull the tool 100 with the J-hook 115 engaged to the cover, to move the manhole cover in a desired direction. The radius of curvature of the inner bend of the J-hook 115 is preferably at least ? of the thickness of a manhole cover, as measured at an edge of a manhole cover and/or at an engagement feature of the manhole cover.

[0041] A light source 200 is provided at the leading edge 190. The exemplary light source 200 is a flashlight (e.g., an LED flashlight) clamped to the bar 105 at the leading edge 190, opposite the L-hook 130. A pair of pipe clamps 205, 210 attached to the bar 105 secure the flashlight 200 to the bar. Light sources other than a removable flashlight may be used without departing from the scope of the invention.

[0042] A handle 170 is attached to bar 105 between the support assembly 150 and trailing edge 185. A pipe clamp 160 and tightening bolt 165 secure the handle 170 in a desired position. The handle 170 extends perpendicular to the bar 105.

[0043] FIGS. 3 and 4 conceptually illustrate use of an exemplary manhole cover lifting tool 100 to engage and raise a manhole cover 305 from a manhole 300, according to principles of the invention. A small lip is provided in the manhole 300 to support the manhole cover 305. The base 135 is supported on the ground, while the bend 120 of the L-hook 130 engages an engagement feature (e.g., a slot, such as slot 306) of the manhole cover 305 for lifting. Downward force is applied by a user to the handle 170 and the bar 105 at the trailing edge 185. The downward force causes the leading edge to raise, thereby lifting the manhole cover 305.

[0044] When the manhole cover 305 is raised, the tool 100 is used to pivot the raised cover 305, as conceptually illustrated in FIGS. 5 and 6. Such pivoting prevents the cover 305 from falling back into a closed position. Such pivoting may be accomplished by exerting a sideways force normal to the bar 105 at the trailing edge 185. Such force causes the bar 105 to swivel (i.e., yaw). Such swiveling moves the manhole cover 305 from a seated position. The manhole cover 305 is then unseated and at least partially removed. The manhole cover 305 may then be pulled (e.g., dragged) completely off the manhole 300 using the J-hook. This exposes the entire manhole for worker entry and exit.

[0045] The exploded views of FIGS. 7 and 8 reveal the cleanout tool 182, an elongated bar attached to the cap fitting 180. Internal threads of the cap fitting 180 threadedly engage the external threads of the trailing edge 185 of the bar 105. Removing the cap fitting 180 from the bar 105 exposes the cleanout tool 182. The cleanout tool 182 is used to scrape dirt and debris from the engagement feature of the manhole cover 305 to permit engagement by the L-hook 130.

[0046] FIG. 9 provides a perspective exploded view of an exemplary compact swivel base 135 for a manhole cover lifting tool 100 according to principles of the invention. The base includes a lower base plate 136, an upper base plate 140 and a turntable bearing 138 between the lower base plate 136 and upper base plate 140. The turntable bearing 138, as shown in FIG. 10, includes an upper bearing plate 230 that attaches to the underside of the upper base plate 140, a lower bearing plate 240 that attaches to the upper side of the lower base plate 136. Such attachments may be by mechanical fasteners (e.g., screws, bolts, rivets) and/or by welding. An annular groove 234, 244 having a semicircular cross section shape is formed in each of the upper bearing plate 230 and the lower bearing plate 240. The annular grooves 234, 244 align when the upper bearing plate 230 overlays the lower bearing plate 240. An annular lip 232 of the upper bearing plate 230 fits within an annular rolled edge of the lower bearing plate 240 when the turntable bearing 138 is assembled. A plurality of balls (ball bearings) 250, 255 are disposed in the space defined between the aligned annular grooves 234, 244. Four or more balls are preferably used. The balls 250, 255 facilitate swiveling rotation of the upper bearing plate 230 relative to the lower bearing plate 240, even when a considerable load is supported.

[0047] The turntable bearing provides a compact low profile bearing assembly that is integrated into the base. The base plates may be rectangular or square. Each may be about 4 inches by 4 inches. Each of the upper plate and lower plate may be ? inch (or less) thick. Thus, the turntable bearing may be less than one inch thick (i.e., one inch in height), and preferably less than ?-inch thick. Thus, the entire base may be less than 1.5 inches, or preferably less than 1 inch in thickness.

[0048] As used herein, the preposition at, when denoting a location, means at or about, which means precisely at and/or in the immediate vicinity of. All dimensions are provided as nonlimiting examples. Dimensions may be varied without departing from the scope of the invention. Labels such as left, right, front, back, top, inside, outside, bottom, forward, reverse, clockwise, counter clockwise, up, down, leading, trailing, distal, proximal or other similar terms such as upper, lower, aft, fore, vertical, horizontal, oblique, proximal, distal, parallel, perpendicular, transverse, longitudinal, etc. have been used for convenience purposes only and are not intended to imply any particular fixed direction, orientation, or position. Instead, they are used to reflect relative locations/positions and/or directions/orientations between various portions of an object. In addition, reference to first, second, third, and etc. members throughout the disclosure (and in particular, claims) is not used to show a serial or numerical limitation but instead is used to distinguish or identify the various members of the group. Further the terms a and an throughout the disclosure (and in particular, claims) do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.

[0049] In addition, any element in a claim that does not explicitly state means for performing a specified function, or step for performing a specific function, is not to be interpreted as a means or step clause as specified in 35 U.S.C. Section 112, Paragraph 6, and is not intended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

[0050] While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components and steps of the invention, including variations in order, form, content, function and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are intended to fall within the scope of the invention as claimed.