US3198362A

US3198362A - Lifting tool

Info

Publication number: US3198362A
Application number: US230071A
Authority: US
Inventors: Harold I Berg
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-10-12
Filing date: 1962-10-12
Publication date: 1965-08-03
Anticipated expiration: 1982-08-03

Description

3, 1965 H. l. BERG 3,198,362

LIFTING TOOL Filed Oct. 12, 1962 2 Sheets-Sheet 1 HAROLD BERG INVENTOR H. l. BERG LIFTING TOOL Aug. 3, 1965 2 Sheets-Sheet 2 Filed Oct. 12, 1962 HAROLD BERG INVENTOR /Mw K/QWM ATTORNEKJ- United States Patent 3,198,362 LHFTING TUGL Harold I. Berg, 1121 McKinley Ave, Fresno, (Iaiif. Filed Get. 12, 1962, Ser. No. 230,071 7 Claims. (Cl. 214-370) The present invention relates to a lifting tool for manipulating manhole covers, storm sewer gates and the like and more particularly to such a tool having a lever system which operates effectively to break loose and to lift such covers with a single motion by the operator.

Inasmuch as manhole covers, storm sewer grates and the like frequently weigh as much as 300 pounds, their removal is usually quite difficult particularly when such covers are disposed within an asphalt surface. The asphalt surface tends to adhere to the cover and frequently necessitates the use of pry bars and sledge hammers to break the cover loose from the surface.

The covers conventionally provide a plurality of apertures to receive the ends of hooked rods by which workmen may engage the cover. By physically lifting such a rod, a workman can elevate the cover sufiiciently so that it can be dragged onto an adjacent ground surface. Such procedure not only is tedious and time-consuming but presents an oneous task which is prone to cause back injury. The apertures in the cover also constitute a hazard in that they readily receive and catch the heels of womens shoes and the like.

Telephone company workmen conventionally employ large plates which serve as work platforms over trenches. These plates, like the manhole covers, provide apertures for lifting rods which normally require two men to reposition the plates as work progresses. Because of the number of back injuries resulting from such heavy lifting, insurance companies have requested that a tool be provided to minimize such hazards.

Therefore, it is an object. of the present invention to provide an improved lifting tool for manhole covers and the like.

Another object is to provide such a tool having improved mechanical advantage so as to minimize physical injury resulting from conventional practices.

Another object is to provide a lifting tool which is capable for breaking loose such covers without prying, chiseling, hammering and the like usually necessary with conventional tools for the purpose.

Another object is to provide a lifting tool for manhole covers which is readily manipulated by a single workman in moving such covers and the like weighing several hundred pounds.

Another object is to provide such a tool which accomplishes such breaking loose and elevational displacement of a cover with a single relatively effortless motion by the workman.

Another object is to provide a lifting tool with a lever system having a dual fulcrum wherein the effective fulcrum is automatically shifted during manipulation of the control lever to provide the optimum mechanical advantage during the breaking loose and lifting operations.

Another object is to provide such a lifting tool for manhole covers having a mobile frame conductive to more ready displacement of the cover from its opening after removal therefrom.

Another object is to provide a lifting tool for manhole covers which is lightweight, of rugged construction and is convenient to use.

Other objects and advantages of the present invention will become more fully apparent upon reference to the descrpition in the specification.

In the drawings:

FIG. 1 is a side elevation of the lifting tool of the 3,198,362 Patented Aug. 3, 1965 ICE present invention disposed adjacent to a manhole cover which is located in a receptacle mounted in a paved area, shown in vertical section, and showing several operating positions of the tool in broken lines.

FIG. 2 is a somewhat enlarged fragmentary side elevation of the tool in its initial cover-engaging position.

FIG. 3 is a view similar to FIG. 2 but showing the tool swung to a cover-loosening position.

FIG. 4 is a substantially vertical section through the tool taken on line 44 of FIG. 2.

FIG. 5 is a fragmentary substantially vertical section through the cover-engaging arm of the tool taken on line 5-5 of FIG. 2.

FIG. 6 is a substantially horizontal section through the tool taken on line 6-6 of FIG. 2.

FIG. 7 is a bottom plan view of the cover-engaging portion of the tool removed therefrom.

Referring more particularly to the drawings, a lifting tool 19 embodying the principles of the present invention is adapted to be rested on a support surface or paved area 11 closely adjacent to a manhole cover 12. The cover is adapted to close a manhole opening 14 circumscribed by an annular support wall 16 which provides an annular ledge 17 to support the cover in substantially flush relation to the support surface 11. An elongated carriage bolt 18 is extended through a suitable aperture in the cover adjacent to its outer periphery and has an enlarged upper head portion 19 and an opposite screw-threaded lower portion 20. A jam nut as-. sembly 21 is positioned on the lower screw-threaded portion of the bolt in spaced relation to the head portion 19 to permit limited sliding movement of the bolt through the cover so that the upper head portion 19 may be elevated from the cover during operation of the tool 10.

The lifting tool 10 provides a base or frame 25 having predetermined front and rear sides 26 and 27, respectively, and includes a pair of opposite transversely outwardly divergent lower leg portions 28 between which is rigidly mounted an enlarged upper support post 29.

An elongated axle 3 is rigidly mounted on the rearward side 27 of the legs in interconnecting relation therewith rotatably to mount a pair of transversely opposite frame supporting wheels 32. While the wheels provide frame mobility, they can be replaced by skids, shoes or the like and successfullly carry out the present invention. A pair of transversely opposite stop blocks or seats 34 is rigidly mounted on the lower legs 23 in a common plane substantially normal to the legs on the forward side of the frame 25.

The tool 1t further includes an elongated rod-like control handle having a bifurcated lower bell crank end 42 which may be integral with or rigidly connected thereto by any suitable connecting members. The opposite legs of the bifurcated bell crank end of the handle are spaced to receive the upper support post 29 of the frame therebetween. The control handle is pivotally mounted on a pivot bolt 46 extended through suitable aligned apertures in the post and in the bell crank end of the control handle. The outer end of the lower hell crank 24 also includes a pair of spaced bores therethrough for mounting a lift arm pivot bolt 47.

A lift arm 59 having an upper curved portion 52 and a substantially straight lower portion 53 is pivotally mounted on the bell crank end 42 of the control handle 40 by the pivot bolt 47 disposedthrough either of the bores provided in the bell crank. A claw head 55 is rigidly mounted on the lower end of the lift arm and provides a wall 56 circumscrioing a substantially rectangular cavity 57. The wall includes a shoe portion 58 which has an elongated slot 59 therethrough of a size slidably to accommodate the carrige bolt 18 and to form a lip adapted to engage the bolt head. As best shown in FIG. 6, the claw head 55 presents a width less than the spacing of the stop blocks 34 so that the head may be motivated therebetween during tool operation. The legs 23 provide buffer surfaces for constraining the cover during lifting. The upper end of the control handle 4% also includes a tubular projection 69 rigidly mounted thereon which is best shown in the broken line position of FIG. 1 as beink adapted to mount a caution flag 61 or other warning device to mark the working area.

OPERATION The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. When it is desired to remove the cover 12 from the manhole opening 14, the lifting tool is positioned closely adjacent to the wall 16 upon the support surface 11 with the claw head 55 registered with the carriage bolt 13 in the cover. As best shown in FIG. 1, the frame is disposed in a substantially upright position and the control handle 4d manipulated to engage the shoe portion 53 of the claw head with the top surface of the cover. The tool is then moved radially outwardly of the cover on the wheels 32; to slide the carriage bolt through the slot 59 with the head portion 19 of the bolt received within the cavity 57. The control handle 4%} is then rocked in a counterclockwise direction, as viewed in FIG. 1, to the most upright dotted line position of' the handle, which corresponds to the position of the tool in FIG. 2, to raise the lift arm 50 and the carriage bolt 18 so that the jam nut assembly 21 abuts the lower surface of the cover. Continued counterclockwise movement of the control handle to the intermediate broken line position of FlG. 1 breaks loose the cover to elevationally position the same substantially vertically against the stop blocks 34, as shown in FIG. 3. is accomplished with a minimum of effort with the me chanical' advantage obtained by the moment arm formed between the pivot bolts 4-6 and 47 of the handle and lift arm, respectively.

Upon continued counterclockwise movement of the control handle 48, the lift arm 50, control handle 46 and 'cover 12 are locked together to fulcrum about the axle of the wheels to the lowermost broken line position of FIG. 1 wherein the cover 12 is completely removed from the ledge 17 of the wall. The elevated cover is then displaced from the manhole opening 14 by movement of the frame along the support surface 11 on the wheels 32 The lifting tool may then be turned around and the cover 12 rested on the support surface ill while maintaining the connection of the claw head with the carriage bolt 18. In such position, the control handle 40 is maintained in the intermediate dotted line position of FIG. 1 adjacent to the manhole opening so that the flag 61 serves as a warning device to alert pedestrains and others of the open manhole. In cases of heavier or more tightly constrained covers, the pivot bolt 47 of the lift arm may be moved to the outer aperture in the bell crank end of the control handle so as to provide a greater mechanical advantage for breaking loose and lifting the cover. When it is desired to replace the cover, the above described pro cedure for removing the cover is merely reversed by manipulation of the control handle in a clockwise direction, as viewed, to lower the cover in place upon the ledge 17 of the wall 16.

In view of the foregoing, it is readily apparent that the present invention provides an improved lifting tool for manhole covers and the like which easily breaks loose such covers without prying, chiseling or beating and elevationally displaces the manhole with a single movement of the control handle. Such operation is provided by the novel linkage and the coaction between the lift arm and the frame stop blocks wherein the cover and such linkage is locked together to shift the operative fulcrum point of the lever system to the axle of the frame. Continued manipulation of the control handle causes the cover to be Such d elevated and supported on the frame support wheels on which the tool and cover are readily movable upon the support surface.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: i

l. A lifting tool for manhole covers including an anchorage comprising a frame having support surface engaging means mounted thereon and cover stop means outwardly extended from the frame adjacent to said surface engaging means, a control handle having a lower bell crank end pivotally mounted on the frame, and an arm pivotally mounted on said bell crank end of the control handle eccentrically of the pivotal connection of therbell crank with the frame having a lower end engageable with said anchorage of the cover, said pivotal connection between the bell crank end of the handle and the frame providing a first fulcrum about which the control handle is motivated to lift the cover substantially vertically a predetermined distance against said stop means, and said surface engaging means providing a second fulcrum for the lifting tool about which the frame, arm and cover are rocked as a unit incident to engagement of the cover with the stop to render the first fulcrum inoperative.

2. A tool for lifting manhole covers from a support surface including anchorage means extended outwardly from the cover comprising a mobile frame having opposite upper and lower sections, and a pair of transversely spaced wheels mounted on said lower section on a common axis supporting the frame in substantially upright position on said support surface adjacent to the cover; a pair of stop blocks mounted on the frame adjacent to said lower section; an elongated control handle having a bell crank end pivotally mounted on said upper section of the frame; an arm having an upper end pivoted to said bell crank end of the handle eccentrically of its pivotal mounting on the frame, and a depending lower end; and a claw head rigidly mounted on said lower end of the arm having a slot therein to receive said anchorage means of the cover, said pivotal connection of the control handle on the frame providing a first fulcrum about which the control handle and arm are rocked elevationally to displace the claw head and manhole cover a predetermined distance against said stop blocks on the frame incident to movement of the control handle in a predetermined direction, said axis of the wheels of the frame providing a second fulcrum about which said tool and cover are pivoted incident to engagement of the cover with said stop blocks for further elevational displacement of the cover.

3. A tool for lifting loads comprisinga frame; means for supporting the frame on a support surface for pivotal movement about a surface fulcrum; control means fulcrumed on the frame; a load engaging arm pivotally mounted on the control means eccentrically of its fulcrum and depending therefrom, said arm having an upwardly facing lip disposed toward the frame and adapted to engage the load for lifting the same; and stop means on the frame engageable by the load, said stop means and arm lip cooperating to grip the load incident to fulcruming the control means to rock said frame about the surface fulcrum and to lift the load for further displacement.

4. A tool for lifting loads comprising a frame; means for supporting the frame on a support surface for pivotal movement about a surface fulcrum, control means fulcrumed on the frame, a load engaging arm pivotally mounted on the control means eccentrically of its fulcrum and depending therefrom, said arm having an upwardly facing lip disposed toward the frame and adapted to engage the load for lifting same, said frame providing a buffer surface adjacent to the surface fulcrum and facing toward the lip in unobstructed spaced relation therewith; and a downwardly facing seat mounted on the frame contiguously above the buffer surface and projecting toward the arm lip, said buffer surface and seat combining to grip the load in cooperation with the arm lip incident to fulcruming the control means to rock said frame about the surface fulcrum and to lift the load for further displacement.

5. A tool for lifting manhole covers having an anchorage comprising a rockable frame; control means pivoted on the frame; a cover engaging arm pivotally mounted on the control means eccentrically of its fulcrum and depending therefrom, said arm having an upwardly facing lip disposed toward the frame and adapted to engage the cover for lifting same, said frame providing a buffer surface adjacent to the surface fulcrum and facing toward the lip in unobstructed spaced relation therewith; and a downwardly facing seat mounted on the frame contiguously above the buffer surface and projecting toward the arm lip, said buffer surface and seat combining to grip the cover in cooperation with the arm lip and anchorage incident to fulcruming the control means to rock said frame about the surface fulcrum and to lift the cover for further displacement.

6. A tool for lifting manhole covers having an anchorage comprising a ground engaging frame adapted to be disposed adjacent to said cover; control means fulcrumed on said frame; an arm pivotally mounted on the control means eccentrically of its fulcrum and depending therefrom, said arm having an upwardly facing lip disposed toward the frame and adapted to engage. the anchorage to lift the cover a predetermined distance incident to movement of the control means relative to the frame in a predetermined direction; and stop means mounted on the frame effective upon further movement of said control means to shift the eifective fulcrum of the tool so that the frame, control means, arm and the cover are movable as a unit to remove the cover from the manhole.

'7. A tool for lifting loads comprising a frame; means for supporting the frame on a support surface for pivotal movement about a surface fulcrum; control means fulcrumed on the frame; a load engaging arm pivotally mounted on the control means eccentrically of its fulcrum and depending therefrom; and stop means on the frame engageabie by the load, said stop means and arm cooperating to grip the load incident to fulcruming the control means to rock said frame about the surface fulcrum and to lift the load for further displacement.

References Qited by the Examiner UNITED STATES PATENTS 310,362 1/85 Bestor 214-379 X 1,444, 949 2/23 Chicoine 214-3 80 2,079,719 5/37 Schuetzer 214-379 2,952,373 9/60 Bie 214-3 75 2,981,426 4/61 Casey 214-382 HUGO O. SCHULZ, Primary Examiner.

MORRIS TEMIN, Examiner.

Claims

1. A LIFTING TOOL FOR MANHOLE COVERS INCLUDING AN ANCHORAGE COMPRISING A FRAME HAVING SUPPORT SURFACE ENGAGING MEANS MOUNTED THEREON AND COVER STOP MEANS OUTWARDLY EXTENDED FROM THE FRAME ADJACENT TO SAID SURFACE ENGAGING MEANS, A CONTROL HANDLE HAVING A LOWER BELL CRANK END PIVOTALLY MOUNTED ON THE FRAME, AND AN ARM PIVOTALLY MOUNTED ON SAID BELL CRANK END OF THE CONTROL HANDLE ECCENTRICALLY OF THE PIVOTAL CONNECTION OF THE BELL CRANK WITH THE FRAME HAVING A LOWER END ENGAGEABLE WITH SAID ANCHORAGE OF THE COVER, SAID PIVOTAL CONNECTION BETWEEN THE BELL CRANK END OF THE HANDLE AND THE FRAME PROVIDING A FIRST FULCRUM ABOUT WHICH THE CONTROL HANDLE IS MOTIVATED TO LIFT THE COVER SUBSTANTIALLY VERTICAL A PREDETERMINED DISTANCE AGAINST SAID STOP MEANS, AND SAID SURFACE ENGAGING MEANS PROVIDING A SECOND FULCRUM FOR THE LIFTING TOOL ABOUT WHICH THE FRAME, ARM AND COVER ARE ROCKED AS A UNIT INCIDENT TO ENGAGEMENT OF THE COVER WITH THE STOP TO RENDER THE FIRST FULCRUM INOPERATIVE.