US 2655399 A
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13, 1953 v G. w. J. MCMILLAN 2,655,399
LIFTING DEVICE FOR SUBSTRUCTURE COVERS Filed Nov. 26, 1948 //v va/vrore. G/LHOME. Wd MC/V/ILLAN BY HIS HTTORNEY\S HHRRIQ/(IECHL Fosra/e & H6 RR/5 Patented Oct. 13, 1953 UNITED STATES PATENT OFFICE LIFTING DEVICE FOR SUBSTRUCTURE COVERS 1 Claim. 1
This invention relates generally to lifting devices and particularly to a tool designed especially for facilitating lifting and removal of vault covers and like relatively heavy objects.
It is customary when removing manhole covers and similar heavy vault covers from their supporting frames to employ various types of lifting tools or apparatus to facilitate such removal. One such tool consists merely of a lifting iron,
an end of which is inserted between the cover and its frame, the tool being pivoted downwardly to pry a side of the cover upwardly. When extremely large heavy covers are to be removed, it has heretofore been necessary to utilize a block and tackle apparatuswhich functions to lift the cover vertically from its supporting frame. While such prior lifting means are capable of lifting the covers, providing the latter are free in their supporting frames, it is well known that the covers frequently become locked in their frames, 1
due to rusting, the accumulation of foreign matter, or the presence of ice and snow, and when such a condition exists, it is difiicult to loosen and remove the covers. Moreover, when covers of the large, heavytypes are to be removed. the large, cumbersome hoisting apparatus must be transported to the site and set up for operation above the cover, and such equipment utilizes space in the work truck which might otherwise be used to greater advantage.
It is an object of this invention to obviate the disadvantages of prior lifting devices by providing a single device which is capable of lifting both relatively light weight and relatively large, heavy manhole covers and similar covers of vaults and v the like. Arelated object is to provide a lifting device which is operativeto raise one side of a vault cover, with the cover pivoting at its opposite side, the device being so constructed that it is detachably connected tothe cover so that,
subsequent to the tilting ofthe cover, the latter can be readily slid laterally from its supporting frame by exerting a pull on the device. a
Another object: is to provide a lifting device or implement which, due to its length, is capable of excessive strain, effectively, avoided.
Another, object is to provide a, liftingdevice of the character referred to, which is adapted to be operated manually when covers of the smaller types are to be lifted, or capable of being actuated by a conventional jack so as to produce the upward force necessary to free and raise relatively large, heavy covers.
Another object is to provide a device of the type indicated which is relatively simple in construction, economical to manufacture and adapted to be stored or transported in a small space.
A further object is to provide a device of the type specified which is self-adjusting so that it can be used in connection with vault covers of various forms without requiring manual "adjustment of its parts.
Further objects of the invention will be apparent from the following specification, and from the drawing, which is intended for the purpose of illustration only, and in which:
Fig. 1 is a perspective view of the present lifting device showing it applied to use for lifting a vault cover;
Fig. 2 is an enlarged side view of the same;
Fig. 3 is a bottom view of the lifting device;
Fig. 4 is a cross-sectional view, taken on line 4-4 of, Fig. 2;
Fig. 5 isa cross-sectional view, taken on line 55 of Fig. 2; and
Fig. 6 is a fragmentary side view of the device, illustrating the manner in which a jack is emloyed therewith for obtaining the upward force necessary to lift a large, heavy cover.
Referring to the drawing in detail, my lifting device 9 or implement comprises a relatively long bar [0 which, as shown in Figs. 3 and 4, is constructed from sheet metal bent into channelshaped cross section, the barhaving a top wall I i and depending side walls [2 and 13. At one end, the top wall H of the bar H3 is extended to pro vide a strip which is bent around a tube iii extending transversely across this end of the bar, the strip being welded or otherwisesecured to the tube and to the lower edges of the side walls i2 and I3. The tube 15 provides a handle by which the implement or' tool can be manually operated.
The end of the bar l0, opposite to the handle end, is curved as indicated at H and welded to this curved end is an arcuate shoe I8 which is adapted to rest upon the upper surface of a cover 20 to be lifted, the shoe also serving. as a pivot about which the tool can tilt within limits when connecting the tool to the cover.
Spaced inwardly from the shoe l8 and extending transversely through, apertures in the side walls It and i3 is abolt 22 which has a head 23 at one end abutting the wall [2 and a nut 24 screwed onto its other end to retain the bolt in place. Surrounding the bolt 22 within the bar it is the bearing sleeve 25 of a U-shaped element 25 which is thus pivoted on the bolt. The pivoted element 26 carries a hook member 2'1. The hook member 2'! is thus pivotally mounted on the bar and adapted to move freely in either direction. Pivotal movement of the hook member 21 is limited in one direction by its engagement with the curved shoe l8 and in the oppothe side walls of the bar.
Secured to the top wall n of the bar It adjacent the shoe I8 is a hook-shaped lifter element 30. Welded to the bottom of the bar i 0 at a point substantially midway of the length thereof is an angular rest 3| which is used for the purpose to be later explained.
Assuming that it is desirable to remove the manhole cover 26 from its supporting ring or frame 36 and that the cover is one of a smaller type capable of being lifted manually, the present lifting device is applied to use in the following manner to facilitate removing the cover. Manhole and similar covers are usually provided with either cross-pins 34 disposed in small wells 35 (Figs. 1 and 2) or with apertures 35 as illustrated in Fig. 6, the pins 34 or the lower edges of the sides of the apertures 35 providing means which can be engaged by a lifting tool or lifting 4 as to cause straight upward movement of the cover 20, it being noted that when two of the devices are employed the cover will not pivot. After the cover 29 has been lifted from its'supporting frame 3% by two workmen in the manner last explained, the cover is moved laterally, with the devices 9 serving as handles, and lowered onto the surface 37. r v H In some vaults, a sub-cover or auxiliary cover 38 (Fig. 2) is employed for preventing foreign matter from dropping through the openings of the main cover into the vault. Such an auxiliary cover is usually light in weight and can be readily removed from the ring 35 which supports it by inserting a suitable hook through a loop 39 of the cover and lifting the latter. The present lifting device 9 is provided with means for facilitating the removal of such an auxiliary cover.
apparatus. To apply the present tool to use in into the well the member is caused to engage the pin 34. To remove the cover 20, a manual upward force is applied against the handle [5 of the lifter bar It) and, due to the fact that the tool cannot pivot upwardly relative to the cover, pivotal movement of the tool effects simultaneous pivotal movement of the cover, the latter pivoting at the side opposite to that to which the tool is connected. After the edge of the cover 20 clears the corresponding edge of the supporting frame or ring 36, a lateral pull exerted on the tool causes the cover to be slid out of the frame onto the surface of the roadway 37 or other surrounding area.
The length of the tool, which may be, for example, 3 feet, when added to the diameter of a common type cover-20 provides a secondclass lever, the effective length of which might be approximately 5 to 7 feet. It is thus apparent that the mechanical advantage derived through the use of the instant lifting device is considerable and consequently the applied force required to pivot thevault cover is much less than that necessary when tools of previous-types are employed. Through the increased leverage, sufficient force can be applied to dislodge or free a cover from its supporting frame even when the cover is wedged therein due to the accumulation of rust, ice, etc.
'If it is desired to lift the entire cover 29 vertically and move the same onto the surface 37,
a pair of the lifting devices 9 is employed. In
'this case, the hook'members 21 of the two devices 9 are engaged withthe pins 34, or the edges. of
the .apertures 35', which are disposed at diametrically opposite points on the cover, and the two lifting devices are simultaneously raised so This means consists of the lifter hook element 3!! which is adapted to be hooked through the loop 35 of the auxiliary cover 33, the device 9 then serving as a long handle by which the cover 38 can be lifted from the vault opening.
As previously pointed out, when large, extremely heavy manhole covers are to be removed so as to gain access to the manhole, considerable difficulty is experienced because of the strain imposed on workmen attempting to pry the cover from its supporting frame. To alleviate this condition, lifting apparatus employing block and tackle means have been employed for lifting the covers and subsequently lowering the same onto suitable rollers by means of which the removed covers can be moved away from the manholes. While such hoisting apparatus is commonly employed and is quite eificient in use, it is relatively large and bulky and requires considerable space in the repair truck which transports it to the site and, moreover, it must be set up and adjusted above the manhole. The present lifting means is capable of lifting such relatively large, heavy vault covers, sucha cover d0 beingshown in 'Fig; 6 as supported by a ring or frame H.
To lift the heavy cover 49, the liftingdevice 9 'isconnected to the cover in the manner illustrated in Fig. 6, that is, with its curved shoe I8 resting upon the top of the cover and its hook member 21 engaged with the edge of the aperture 35'. In order to augment the applied upward force andthus relieve the strain which might otherwise be imposed on the workman performing the lifting operation, the presentinvention contemplates the provision of means for mechanically applying the necessary force. In Fig. 6 the force applying means consists of a conventional vehicle jack 42 which may be either of the mechanically or hydraulically actuated types. After the lifting device 9 has been positioned as shown in Fig. 6, the jack 42 is moved to a'position length of circular rod or pipe, is slid under this portion and the device 9 disconnected from the cover. The lifting operation explained above is then repeated at the opposite side of the cover 40 to elevate the. latter above thering Hand" to permit the placing of a second roller'under the cover. Withfthe cover 40 thus completely removed from the ring 41, it can be readily moved on the rollers (not shown) along the surface 45 to uncover the vault opening. As will be apparent, the magnitude of the upward force obtainable through the use of the jack 42 is such that the large, heavy cover 40 can be readily freed from the supporting ring 4| even when these parts are wedged or adherently joined by rust, dirt or ice.
It will be observed from the foregoing that my invention provides a simple, yet highly efiicient means for removing covers from the openings of manholes, vaults and other subterranean chambers. The improved lifting device can be readily transported and conveniently connected to a cover to be lifted and quickly disconnected therefrom following the lifting operation. By means of the present device the force applied by the work man is multiplied so that large, heavy covers can be readily removed when the covers have the tendency to resist removal due to the accumulation of dirt, rust, ice or other foreign matter between the cover and its supporting frame. Since the lifting force is applied while the workman assumes a natural and comfortable stance, injury to the workman, due to excessive strain is avoided. As another feature of the present invention, the improved lifting tool is adapted to be used in conjunction with a jack which is capable of exerting an upward force against the tool necessary to dislodge and elevate the vault cover. Moreover, the present lifting tool is economical to manufacture, is strong and durable, and is adapted for use in removing all of the various types of vault covers now in common use.
While the vault cover removing tool or implement has been herein described as embodied in a preferred from of construction, by way of example, it will be apparent that it is susceptible of various modifications which fall within the scope of the appended claim.
Iclaim as my invention:
A lifting device adapted for lifting a vault cover, said cover having an internal abutment by which it can be lifted from a supporting frame, comprising: a lifter bar of channel shape cross section having a top wall and depending side walls, the bottom edges of said side walls at one end of said bar terminating in curved surfaces; a curved elongate shoe secured to and extending between said curved surfaces, said shoe being restable against the exposed surface of the cover; a transverse handle secured to the other end of said bar; and a hook member pivoted between said side walls adjacent said shoe and having a curved hook portion engageable beneath said abutment of the cover, said shoe and said hook member together rigidly connecting said lifter bar to the cover, when an upward force is applied to said bar through said handle, so as to effect unitary pivotal movement of said bar and the cover with respect to the supporting frame, said curved shoe being wider than said bar so as to provide a bearing surface of sufficient width to avoid excessive longitudinal axial rotation of said bar with respect to the cover upon which said shoe rests.
GI'LHOLIE W. J. MCMILLAN.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 322,019 Spencer July 14, 1885 649,846 Horth May 15, 1900 867,549 Bentley et a1 Oct. 1, 1907 953,138 Hale Mar. 29, 1910 1,553,270 Saffold Sept. 8, 1925 1,829,490 Parrish Oct. 27, 1931 2,086,318 Jackson July 6, 1937 2,210,904 Durant Aug. 13, 1940 2,348,978 Kinner May 16, 1944 2,439,288 Evans Apr. 6, 1948 2,599,938 Price et a1 June 10, 1952