US2699354A

US2699354A - Lifting device

Info

Publication number: US2699354A
Application number: US388228A
Authority: US
Inventors: Kok Marinus
Original assignee: METEOOR NV BETONFABRIEK
Current assignee: METEOOR NV BETONFABRIEK; N V Betonfabriek De Meteoor
Priority date: 1952-11-19
Filing date: 1953-10-26
Publication date: 1955-01-11
Anticipated expiration: 1972-01-11

Description

M. Kok

LIFTING DEVICE Jan. 11, 1955 2 Sheets-Sheet 1 Filed Oct. 26, 1953 IN VEN TOR AGENT M. KOK

LIF'TING DEVICE Jan. 1 1, 1955 2 Sheets-Sheet 2 Filed Oct. 26, 1953 PIC-3.4

FIE-3.3

FIG.6

INVENTOR WWW/V0.5 49K BY 722cm ATTORNEY United States Patent Oflice.

2,699,354 Patented Jan. 11, 1955 LIFTIN G DEVICE Marinus Kok, De Steeg, Netherlands, assignor to N. V.

Betonfabriek De Meteoor, Rheden, Netherlands Application October 26, 1953, Serial No. 388,228

Claims priority, application Netherlands November 19, 1952 4 Claims. (Cl. 294-96) The invention relates to improvements in a lifting device, especially for lifting heavy articles.

or lifting articles of great weight, e. g. large concrete rafts or slabs, it is known to provide the article with a nonround hole into which a lifting rod provided with a hammer-shaped head may be inserted, whereupon this rod is turned a quarter of a turn so that the head of the rod engages the undersurface of the article to be lifted. Concrete rafts or slabs which are intended for composing a dock yard, a factory yard or a factory floor which must stand trafiic of very heavy vehicles would be weakened too much by a non-round hole.

The purpose of the invention is the provision of a lifting device which is especially adapted to lift heavy concrete articles having a cylindrical hole provided with a metal lining.

Another purpose of the present invention is the provision of a lifting device of such a kind that the cylindrical hole in the article to be lifted can be kept as small as possible in order to weaken the article to a minimum degree.

Still another purpose of the invention is the provision of a lifting device having pivotal spreading elements which engage the lower edge of the hole, e. g. the interior edge of the metal lining of the article to be lifted in such a way that the pivots of the spreading elements do not transmit the lifting force.

Still another purpose of the invention is the provision of a lifting device which is easily manufactured.

Still another purpose of the invention is the provision of a lifting device having spreading elements which are quickly and easily detachable if this is desired for cleaning or other purposes.

Still another purpose of the invention is the provision of a lifting device having spreading elements which can quickly and easily be replaced by spreading elements of different dimensions if the lifting device is to be used for lifting articles having holes of a larger diameter than the minimum diameter for which the device has been designed.

Still another purpose of the invention is the provision of a lifting device having an abutment intended to rest on the upper surface of the article to be lifted without needing to insert a tool between the abutment and the article if after releasing the lifting force, it is desired to remove the lifting device from said article.

The characteristic features and the advantages of the lifting device according to the invention will follow from the subjoint description and the claims appended thereto.

In order to elucidate the invention reference is made to the accompanying drawings in which Fig. 1 is an elevation of a portion of a slab in which a lifting device according to the invention has been inserted, said device being shown in the position before starting the lifting operation,

Fig. 2 is a vertical section of the object and of the lifting device in the same position as Fig. 1,

Fig. 3 is a section of the lower portion of Fig. 2, however, with the device in the position before starting the lifting operation,

Fig. 4 is an elevation of a spreading element,

Fig. 5 is an elevation of the lower portion of an element of the lifting device shown in Fig. 2, but on a larger scale, and

Fig. 6 is a view of the resilient ring adapted to act as a fllllcrum for the spreading elements, equally on a larger sca e.

De Steeg, Municipality With reference to the drawings a lifting bolt 1 is screwed into a threaded yoke 2 and is locked in position by a lock not 3. The yoke 2 is welded at 4 to the legs of a U-shaped strap 5 adapted to receive a lifting hook.

The object to be lifted, e. g. a concrete slab 6, has a hole provided with a cylindrical lining 7, which is welded to reinforcing rods 8. The upper face of the lining 7 is flush with the upper face of the concrete slab 6 while the lfower end of the lining is slightly higher than the underace.

The lower end of the lifting rod 1 is provided with a conical head 9, the diameter of the larger end of which is such that said head can be inserted through the lining 7. A sleeve 10 provided with a horizontal flange 11 near its upper end, is axially movable with respect to the bolt 1 and has an exterior diameter which is a little smaller than the interior diameter of the lining 7. The upper portion of the sleeve 10 is provided with a handle consisting of a ring 12 and spokes 13, the latter being welded between said ring 12 and said flange 11.

Six radial slots 14 are formed in the lower end of the sleeve 10 which serve as guides for the upper ends 15 of spreading elements 16. These elements are pivotally connected to the sleeve 10 by means of an open resilient wire ring 17 which engages a circumferential groove 18 arranged in the slotted end of the sleeve 10, and recesses 19dfoir5ned in the spreading elements 16 below the upper en s If it is desired to lift a concrete slab 6, the lifting bolt 1 with the sleeve 10 and the spreading elements 16 which are pivotally connected thereto by the spring wire 17, is inserted into the lining 7 till the flange 11 of the sleeve 10 rests on the upper face of the slab 6. This position is shown in Fig. 2. Thereupon the strap 5 is hooked on the book of the lifting cable and the lifting rod is raised, while the sleeve 10 is held down by means of the handle 12. The elements 16 are spread by the conical head 9 until these elements are clamped between the head 9 of the lifting bolt 1 and the edge 20 of the lower end of the lining 7 (vide Fig. 3). In this way there is a. positive engagement between the head 9 of the lifting bolt 1 without the fulcrum about which the spreading elements 16 are adapted to move and which is formed by the: spring wire 17, are stressed by the lifting force.

If it is desired after lifting the slab 6 and after lowering the same again until it rests on a support, to release the lifting device, the lifting bolt 1 is lowered until the elements associated therewith take again the position as shown in Fig. 2. The spreading elements 16 lie again flat against the shank of the lifting bolt 1 so that by means of the handle 12 the sleeve 10 can be raised and thereupon the lifting bolt is pulled from the lining 7 of the hole in the slab 6.

It follows from the above that the pivotal connection between the sleeve 10 and the spreading elements 16 takes a minimum space so that the overall diameter of the sleeve 10, the lifting bolt 1 with its head 9, the wire ring 17 and the spreading elements 16 is the smallest imaginable diameter for a lifting device with positive action of the spreading elements. This is of utmost importance if it is desired to keep the hole in the article as small as possible.

The spring wire ring 17 rests in the bottom of the peripheral groove 18 in the sleeve 10, so that the spreading elements 16 are not urged againstthe lifting rod 1. The upper ends 15 of the spreading elements 16 form an angle with that portion of the spreading elements which is below the wire ring 17, which is equal to the angle between the shank of the lifting rod 1 and the conical head In this way the outward movement of the spreading elements 16 is allowed with a minimum clearance of the upper ends with respect to the lifting bolt 1.

The spring wire ring 17 has further the advantage that the assembly of the device is very easy. Further the spreading elements may easily be withdrawn from the slots 14 since it is only necessary to widen the ring 17 so far that it leaves the groove 18. This enables cleaning the device in a very easy way, while it is also possible to substitute the spreading elements 16 by other spreading elements having an upper portion of the same shape as the portion 15, but a lower portion of larger dimension in a radial sense, so that the device can be readily adapted 2. A lifting device, comprising a lifting bolt having to lift articles having a larger hole. v an enlarged lower end portion forming a unit with the It is remarked that the device described hereabove, shank of said bolt, a sleeve adapted to slide along said apart from lifting objects, is also adapted for other purshank, a plurality of axial slots in said sleeve engaging poses, e. g. for temporarily fixing a cable to a horizontal 5 the upper portions of a plurality of spreading elements, sloping or vertical. surface of a block, provided that bean open ring of spring wire forming a fulcrum which yond the end of'the hole there is a cavity adapted to pivotally connects each of said spreading elements to the receive the head of the lifting'rod. slotted portion of said sleeve.

Having described the invention and an embodiment 3. A lifting device, comprising a lifting bolt having an thereof, what is claimed is: 10 integral conical head at its lower end, a sleeve adapted to 1. A lifting device, comprising a lifting bolt having an slide along said bolt, a plurality of axial slots in the lower enlarged lower end portion forming a unit with the shank end of said sleeve, a spreading element in each of said oftsaid bolt, a sleeve adapted to move axially with reslots, a fulcrum which pivotally. connects the upper porspect to said bolt, a plurality of axial slots in said sleeve tion of each spreading element to the slotted portion of which are open at the lower end, a circumferential groove 15 the sleeve and a radial flange or similar abutment arin the slotted lower portion of said sleeve, a plurality of ranged on thenon-slotted portion of said sleeve. spreading elements the upper portion of which engage 4. A lifting device as claimed in claim 3, in which said said slots, recesses in the exterior faces of the upper porsleeve is provided with a handle at a higher level than said tions of said spreading elements, and an open spring wire radial flange or similar abutment.

ring engaging said circumferential groove in the sleeve 20 and said recesses in the spreading elements. No references cited.