Slab lifting apparatus
US 2686420 A
Description (OCR text may contain errors)
Aug. 17, 1954 P. N. YOUTZ 2,686,420
SLAB LIFTING APPARATUS Filed Nov. 30, 1948 3 Sheets-Sheet l MIME/V701?" P///[ l! M 70072 ATTORNEY Aug. 17, 1954 P. YOUTZ SLAB LIFTING APPARATUS 3 Sheets-Sheet 2 Filed Nov. 30. 1948 I've/0 5 6 3 4 6 a a 2 2 E 0 N i. F 3
x 3 7 6 0 6 6 11 1 1:11111111111fl E 111111111111111111111111C1111111111111111111111111111113 113; 0 6 m 8 5 M Aug. 17, 1954 Filed Nov. 50. 1948 P. N. YOUTZ SLAB LIFTING APPARATUS 3 Sheets-Sheet 3 Patented Aug. 17, 1954 UNITED STATES PATENT OFFICE SLAB LIFTING APPARATUS Philip N. Youtz, Yorktown Heights, N. Y.
Application November 30, 1948, Serial No. 62,771
1 3 Claims.
This invention relates to building construction and especially to the erection of the columns and floors of a building.
The system of erecting buildings with which this invention is concerned involves pouring the various floors of the building above the ground floor as individual units and at ground level and in superposed relation on the ground floor, and then raising the various floors into their proper positions in the building and connecting them to the supporting columns.
The common method now employed in erecting buildings with concrete floors is to pour the floors in situ as the erection of the building proceeds. This involves the building of centering and forms for the various floors and also the operation of elevating the cement for any floor to the level which the floor is to occupy in the building preparatory to pouring it into the completed forms, all of which involves considerable labor and expense.
Such labor and expense, however, is eliminated when the pouring of the floors is all done at ground level. Moreover, when each floor above the ground floor is poured on the floor below the only forms necessary for the pouring of any floor involves a peripheral screed or wall to determine the outline of the floor, each floor, after it is poured, constituting the main portion of the form necessary for pouring the floor above. The present invention relates particularly to the lifting means for raising into their proper positions in the building the floor slabs which have been poureo at ground level.
In erecting a building having steel columns and concrete floors by means of lifting apparatus involving my invention, the procedure is substantially as follows.
The ground is first leveled and smoothed for the ground floor, which may be a cellar floor or a basement floor or a floor at ground level. Excavations are then made for the footings of the columns and trenches dug for the peripheral foundations. footings for the columns and the peripheral foundations may, if desired, be cast directl in the ground and Without the use of specially built forms.
The structural columns are then set up on the footings and secured thereto, after which the reinforced ground floor is poured around the columns thereby bracing them securely from all directions.
The finished ground floor, which as stated above may be the cellar floor or a basement floor, .or a
floor at ground level, is then covered With tar paper or similar waterproof material and a collar is placed around each column on the ground floor;
The second floor is then poured as a unit directly on the ground floor, said second floor unit being in the form of a-monolithic slab. Before the second floor is poured however, a suitable screed or wall will be built to determine the edge contour of the second floor. The collars above referred to serve to keep the concrete material of the second floor from contacting the columns and provide said floor with openings through which the colurnns pass, and also function as lifting plates to whi h the lifting apparatus can be attached for raising the floor, and in addition furnish the supporting plates for the floor after it is connected to the column.
If the building is to be a one-story building, then the second floor monolithic slab will constitute the roof of the building, and after it has set properly, then it is raised as a single unit into its position in the building by lifting means involving my invention and associated with the columns. After the monolithic second floor slab has been elevated into its permanent position, it is then connected to the columns. During this lifting operation, the entire weight of. the second floor is carried by the columns.
If the building is to be one having two or more stories, then after the second floor monolithic slab has been poured and has set and while it is still at ground level, the third floor is poured directly on the second floor, as above described, and this procedure will be repeated until all the necessary floors and the roof slab have been poured, each floor being in the form of a monolithic slab and all the floors resting on the ground floor in superposed relation.
After all the floors have been thus poured at ground level, the top floor is raised by novel lifting means associated with the columns as above described to a position somewhat above the predetermined position for the second floor and is temporarily secured to the columns. The same operation is repeated with respect to all the other floors except the second fioor, as a result of which all of the floors except the second floor will be temporarily secured to the columns at positions sli htly above the permanent position for the second floor.
The second floor is then similarly raised to its permanent position and permanently secured to the columns. After this has been done, the top floor and the other floors above the third floor are raised one by one to positions slightly above the third floor level and each floor is temporarily secured to the columns. The third floor is then similarly raised to its permanent position in the building and permanently secured to the columns.
The above operation is repeated until all floors have been lifted to their proper levels and permanently secured to the columns.
In order to give an understanding of my invention, I have illustrated in the drawings a selected embodiment thereof which will now be described, after which the novel features will be pointed out in the appended claims.
In the drawings:
Fig. 1 is a perspective view illustrating my invention and showing a building construction in which the columns have been erected, the ground floor poured and the second floor also poured on the ground floor.
Fig. 2 is an enlarged plan of the portion of a floor through which a column extends, the column and the tension screw being shown in section.
Fig. 3 is a sectional perspective view showing part of the lifting yokes by which the monolithic floor slabs are lifted into position.
Figs. i, 5 and 6 are diagrammatic views showing various steps in the erection, in accordance with my invention, of a building which has five floors and a roof slab.
Fig. '7 is a fragmentary elevation illustrating one of the columns with its lifting jack and also illustrating the ground floor with the second floor poured directly thereon.
Fig. 8 is a view of the tension or lifting screw.
Fig. 9 is a fragmentary view showing the foot at the lower end of the tension screw.
Fig. 10 illustrates the jack support which is mounted on each column.
Fig. 11 is a plan showing lifting yoke in posi tion.
Fig. 12 is a fragmentary sectional view showing the operation of the safety wedges.
Fig. 13 is a view illustrating the building operation in accordance with my invention showing the second floor after it has been raised and connected to the column.
Fig. 14 is a plan view of the collar which is used when pouring all floors above the ground floor.
Fig. 15 is a plan showing blocking used for bracing collar rigidly to the column.
Figs. 16 and 17 are standard angle iron connections by which the various floors can be attached to the columns after they have been raised.
Fig. 18 is an enlarged section on the line I8-l8, Fig. 11.
Fig. 19 is an enlarged perspective view of one of the lifting yokes.
As stated above, the first step in erecting a building in accordance with my invention is to level the ground I where the building is to be located preparatory to pouring the ground floor, which as stated above, may be a cellar floor, or a basement door, or a floor at ground level.
The next operation is to provide excavations 2 for the footings on which the supporting columns are to be erected and then to pour the footings 3 in said excavations. After the footings are properly set, then the columns 4 are erected thereon and are anchored thereto in any suitable or usual way. As shown in Fig. 7, the footing 3 has anchor bolts 5 embedded therein which extend through a bearing plate 8 welded or otherwise secured to the bottom of the column 4 and which carry clamp-ing nuts 1 by which the foot plate 8 is anchored to the footing.
Any number of columns 4 may be used depending upon the size and character of the building. There is shown in Fig. 1 of the drawings a building which would require four columns d, and these are shown as located well inside the marginal edges of the building. The location of the columns, however, may be varied and will depend upon the design and character of the building being erected.
The columns herein shown are steel columns having a wide flange or H section, but the invention is not limited to any particular type of column, and columns of concrete or other material may be employed without departing from the invention.
The columns 5 as initially erected will preferably have a length to extend somewhat above the position in the building to be occupied by the second floor.
After the columns have thus been erected, then the ground floor 8 is poured, and in many instances it will be satisfactory to pour it directly on the ground surface prepared for it. In pouring the ground door the cement is poured around and in contact with the columns 2 so that when the ground floor has set, it will serve to brace the columns from all directions.
After the ground floor 8 has set properly, then the second floor 9 is poured directly on the ground floor. Before this is done, however, the ground floor 8 is covered with tar paper or some other suitable waterproof material so as to prevent the second fioor, when poured, from adhering or bonding to the ground floor. If desired fine sand may be sprinkled on the ground floor before the tar paper is applied.
Furthermore, before the second floor 9 is poured, a collar IE! is placed around each column directly on the ground floor. This collar has an opening H therethrough of a. size somewhat larger than the column and it is provided with a vertical wall I2 having a vertical dimension approximately equal to the thickness of the second floor and is also provided with a base flange l3 extending outwardly in all directions, which flange i3 is provided with bolt holes Hi. When the collar is placed in position on the ground floor around each column, bolts i5 are inserted upwardly through the holes Id of the base flange 83 with the heads of the bolts on the under side of the flange l3, and these bolts are preferably covered with paper so as to prevent the concrete of the second floor from bonding thereto. The bolts have a length somewhat greater than the thickness of the second floor.
After each column has been provided with its collar 10 as above described, then. the second floor 9 is poured on the ground floor and at ground level. It will be understood that before this is done, a screed or curb will have to be built around the periphery of the floor so that the second floor when poured will have a proper peripheral shape. This building of such a screed 0r curb is a simple and inexpensive matter however.
The second floor 5, when poured, is in the form of a monolithic slab and may constitute the complete second floor unit. It will be understood, of course, that this monolithic second floor slab will be provided with the usual steel reinforcings.
If the building being erected is a one-story bu lding, then the monolithic second floor slab 9 which has been poured at ground level will constitute the roof slab of the building, and after the said second floor slab has set properly, it is then raised as a unit into its permanent position in the building and secured permanently to the columns. For thus raising the monolithic second floor slab i I propose to use tension screws or threaded lifting rods it, at least one for each column, and to attach the lower ends of the tension screws to the second floor slab 9 and to provide means at the upper ends of the columns for acting on said screws and raising them thereby lifting the second floor slab into its permanent position. These tension screws it may conveniently be located between the flange-s of the columns d as shown in Figs. 1 and 2. For connecting the tension screws to the ground floor slab, I have employed lifting elements I! which are referred to as vokes and which are detachably secured to the second floor slab through the medium of the bolts it above referred to as best seen in Fig. '7. Each lifting yoke I? has associated with it a latch 18 which has a biiurcated inner end l9 adapted to embrace the lower end of the tension screw it. The tension scr it is formed at its lower end with a foot 29 which engages the under side of the latch l8, so that when a lifting force is applied to the tension screw It, it will operate through the latch iii and the lifting yoke I? to raise the second floor slab t. While the lifting yoke ll may have any suitable construction, I have herein shown a lifting yoke which comprises two spaced angle iron members 68 which are secured to the slab to be lifted by the bolts 15, said angle iron members 63 having welded thereto at one end thereof the vertical web 6 1 of a member the latter having a head portion iii: and also a foot portion at which rests on the floor slab. The latch member i8 is located between the two angle iron members iii and rests at its outer end on a cross member 55 which is supported on the feet 65 of the members 52. The lifting force which is applied to the latch is through the lifting rods it is transmitted to the yoke I? through a cross member 61 which extends beneath the head portions 63, as shown in Fig. 19.
The latch it is shown as movably mounted in the lifting element ii so that it can be withdrawn from engagement with the tension screw and for this purpose said latch has a handle '2! on its outer end which may be grasped for withdrawing it from engagement with the lifting screw.
As stated above, each tension screw it cooperates with means located at the top eof and mounted on the corresponding column for raising the screw so that the entire weight of the second floor slab 9 as it is raised is carried by the columns 4.
A preferred form of lifting means is a center hole hydraulic jack 22 which is mounted on the column d in a position so that the tension screw it extends through the center or" the jack. Such center hole hydraulic jacks are in common use and therefore a detailed description of them is not deemed necessary. Each lifting jack 2% is carried on a jack support which comprises a supporting plate 23 mounted on the column and secured thereto by angle members 2 and also a top plate 25 which is supported on the jack supporting plate 23 by means of supporting elements 2%.
The tension screw it extends loosely through 6 both plates :23 and 25' and through the jack 22, and it has screw threaded thereto two nuts 2'! and 28, the nut 28 being located above the top plate 2:5 and constituting a holding nut and the nut 27 being located between the jack 22 and the top plate 2.5 and constituting a, lifting nut.
In raising the second floor t, the jacks will be in their lowered position and the lifting nuts 27 screwed down into contact with the rams of the jacks. The jacks are then operated and by their engagement with the nuts 2?, they raise the screws I6 and the second floor 9 one upward step, the screws moving upwardly through both plates 23 and 2%. The holding nuts 28 are then turned down on the screws it until each engages the corresponding top plate 25 and the ram of each jack is then lowered ready for its next operation and each lifting nut 2? is turned down on its screw [5 until it engages the lowered ram of the jack. The engagement of the holding nuts 28 with the top plates 25 serve to pre vent retrograde movement of the screws while the jack is being lowered and thus support the floor in its partially raised position.
The above operations are repeated over and over again thereby raising the second floor 9 step by step to the position it is to occupy in the building, which position is indicated by the dotted lines in Fig. l and in full lines in Fig. 13. The lifting apparatus above described may be considered as comprising an hydraulic jack mounted on each column, a threaded tension screw or lifting rod for each jack, the lower ends of the tension screws being connected to the floor to be raised, a nut screw threaded on each tension screw and cooperating with the corresponding jack to transmit the lifting effort of the jack to the tension screw and move it upwardly, thereby raising the floor to be lifted, a supporting plate or abutment member stationarily mounted on each column and through which the corresponding tension screw loosely .passes and moves upwardly during the lifting stroke of the jack, and a second nut screw threaded on each tension screw above the corresponding supporting plate and free to be screwed downwardly into engagement therewith during or after each upward movement of said tension screw, whereby when the jack is lowered for another lift said second nut cooperates with the supporting plate to prevent retrograde movement of the tension screw and thus to support the partially raised iioor.
An advantage of this construction is that when either not is supporting the load it has station-- ary engagement with either the jack or the supporting plate, and when each nut is being adjusted downwardly on the tension screw it is supporting no load and can therefore be easily turned on the rod.
The use of the hydraulic jack involves no turning of a nut on the tension screw while the lifting force of the jack is being transmitted to the tension screw through said nut.
As a precautionary safety measure, I propose to use safety devices which cooperate with each of the collars it in the floor 8, which safety de vices permit the rising movement of the floor but become operative automatically to prevent any downward movement or said floor, thereby preventing the fioor from falling should any of the lifting equipment fail.
While any suitable form of safety device may be employed, that herein shown comprises pairs of wedges 35, 3'6 interposed between the fiat flange of each column and the vertical wall 12 of the collar H). The wedge 35 of each pair is widest at the top and thinnest at the bottom and is secured to the collar in some suitable way. The wedge 36 has its thin edge at the top and its wide end at the bottom and it is supported by suitable springs 37 which normally hold it in the position shown in Fig. 12.
As the floor 9 is raised, the yielding support for the wedges 3% allow them to yield downward slightly so as to permit the floor to be freely moved upwardly. If, however, the floor should tend to move downwardly, the springs 37 together with the friction of the wedges 35 against the column will crowd the wedge members 35 between the column and the wedge members 35 and will therefore lock the floor against downward movement.
When the second floor 5 has been thus raised to its permanent position, it is then permanently secured to the columns 6 in any suitable or usual way, as by means of supporting brackets is, and blocking 38, 39 is inserted between each column and the vertical Walls [2 of the collars ill thus locking the top of each column 4 to the corresponding collar. The jacks 22, the jack supports, the tension screws i6 and the lifting yokes ll may then be removed, and the building is in condition to have the walls built in any known or usual way.
If the building is to have more than one story, then after the second floor has been poured and has set, the third floor will be poured directly on the second floor at ground level as above described and, if the building is to have a fourth floor, it will be oured on the third floor also at ground level, this operation being repeated until all the fioors have been poured, one on the other, at ground level as illustrated in the diagram shown in Fig. 4, wherein 8 indicates the ground floor, 9 the second floor, 29 the third floor, 39 the fourth floor, and 3| the fifth floor, the columns in said figure being indicated at 4.
Prior to pouring each floor, a collar i G is placed around each column on the floor below and the bolts 25 for the lifting yokes are inserted through the holes i l in the flanges 13 as above described. In order to avoid any interference between the bolts 25 in any floor slab with the bolts in the floor slabs above and below, it is proposed to make the holes M in pairs, and as shown in Fig. 14, there is a pair of holes H3 at each corner of the flange l3. p
In the building of one fioor slab, the bolts 15 will be placed in one hole 54 of each pair of holes, each bolt being wrapped in paper so as to pre vent it from becoming bonded to the concrete when the floor is poured.
For building the next floor, a collar with a bolt i extending through one hole M of each pair of holes is placed around each column on the floor last poured, and in locating the bolts, they are placed in the other hole of each pair of holes from that in which the bolts in the collars of the floor below are located. When the collars i6 are placed in position, the upper exposed ends of the bolts IS in the floor below will extend through the empty holes Hi in said collars, and there will therefore be no interference between the bolts in each floor and those in the floors below and above.
After all the floors have thus been poured at ground level one on another in superposed relation, then all the floors above the second floor 9 will be raised as above described to a position ell) slightly above the second floor level and each, as it is raised, will be temporarily secured to the columns 4. The second floor 9 is then raised as above described and permanently secured to the columns.
It should be stated that after the top floor has been raised and temporarily secured to the columns 4, then lifting yokes ll will be secured to the next floor below, that is, the then top floor on the stack of superposed floors, and the nuts 2'5, 28 will be turned to lower the lifting screw is into position to be connected to said lifting yokes.
The jacks 22 are then actuated so as to lift the floor then remaining on the top of the stack of floors into a position slightly above the second floor level and it will be temporarily secured to the columns.
This operation will be repeated for each of the floors in the stack of fioors until the second floor of the building is raised to its proper position and permanently secured to the column.
At this stage in the building operations, the second floor of the building will be located in its permanent position in the building and permanently secured to the columns and all the floors above will be located slightly above the second floor and temporarily secured to the columns.
If the columns as initially erected extend only slightly above the second floor level, then an additional column section will be mounted on each column so as to carry it slightly above the third floor level. Before this is done however, the jack supports will have to be removed from the top of the columns as initially erected, and after the additional column section has been mounted, then said jack supports are in turn mounted on and attached to the top of the extended column and the tension screws are placed in position ready for cooperation with the jacks in again raising the various floors. The above described operations of raising the floors one by one will then be repeated to raise all floors above the third floor into positions slightly above the third floor level, each floor being temporarily secured to the columns when so raised, and the third floor will be raised into its permanent position and permanently secured to the columns.
These operations are repeated until each of the fiOOls has been brought into its permanent location in the building and permanently secured to the columns. It will be noted that after each floor slab has been raised to its proper level and permanently secured to the columns, the lifting element l I will be removed from the slab.
While my invention is especially applicable for use in erecting buildings having concrete floors, yet the lifting equipment might also be used in erecting buildings that have other types of floors by a system which involves building each of the floors as a unit at ground level and with the floors in superposed relation, and then raising the floors to their proper positions in the building, floor by floor and story by story, each floor being permanently secured to the supporting columns when it has been lifted into its proper position.
While in carrying out my invention I prefer to employ supporting columns which are to be the permanent structural columns of the building, yet the invention would not be departed from if the columns first erected were temporary columns which were used in raising the floors to their proper level and which were subsequently replaced by permanent structural columns or piers or bearing walls.
The method of erecting a building herein described has been made the subject of a divisional application, serial Number 350,313, filed April 22, 1953.
1. Lifting apparatus for raising a completed floor slab from ground level to its appointed upper floor level in a partially constructed building provided with columns which ultimately constitute permanent columns of said building, said lifting apparatus comprising an hydraulic jack for each column adapted to be mounted on the top thereof, a threaded lifting rod for and depending from each jack, a lifting element for each lifting rod adapted to be detachably secured to the fioor slab to be lifted, means for detachably connecting the lower end of each lifting rod to its lifting element, a lifting nut screw threaded on each rod above the corresponding jack and cooperating therewith to transmit the lifting force thereof to the rod, a supporting member for each lifting rod adapted to be stationarily supported on the corresponding column and through which said lifting rod loosely passes, a holding nut screw threaded to each lifting rod above the corresponding supporting member and free to be turned downwardly on said rod as it is moved upwardly through said supporting member during the lifting stroke of the jack, said holding nuts cooperating with the supporting members to hold the rods against retrograde movement during the return stroke of the jack, said lifting nuts being free to be turned downwardly on their rods into engagement with the jacks when the latter have been returned to lowered position after each lifting effort, whereby no nut is supporting any load while it is being turned downwardly on its rod.
2. Lifting apparatus as described in claim 1, in which each lifting rod has a head at its lower end and the means detachably connecting each lifting rod to its lifting element includes a latch member slidably mounted in the corresponding lifting element and having a bifurcated end which, when the latch is in its operative position, embraces the lifting rod and overlies the head thereof.
3. Apparatus for raising an upper floor unit which has been built as an independent floor unit from ground floor level to its proper position in a partially constructed building which i provided with columns that ultimately form permanent columns of the completed building and which extend above the level to which said upper floor unit is to be lifted, said apparatus comprising a jack support adapted to be detachably mounted on the top of each of said columns, each jack support having spaced top and bottom plates rigidly connected together, an hydraulic lifting jack mounted on the bottom plate of each jack support and situated between the plates thereof, a screw threaded lifting rod for each jack, each lifting rod being screw threaded throughout its length and adapted to extend lengthwise of the column closely adjacent thereto and also extending loosely through both plates of the corresponding jack support, means for detachably connecting the lower end of each lifting rod to the floor unit to be raised, a lifting nut screw threaded on each lifting rod and located between the corresponding jack and the top plate of its jack support and through which said jack transmits its lifting force to the lifting rod and thus to the floor slab to be lifted, and a holding nut screw threaded to each lifting rod above the corresponding top plate, said holding nuts being free to be turned downwardly on the lifting rods into engagement with the top plates as said rods are moved upwardly by the jacks, thereby to prevent retrograde movement of any rod when the corresponding jack is being reset for another lifting effort.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 216,326 Hyde Jan. 10, 1879 998,403 Sanguinetti July 18, 1911 1,066,436 Peltzer July 1, 1913 1,619,570 Duchemin Mar. 1, 1927 1,693,624 Strunge Dec. 4, 1928 1,909,696 List May 16, 1933 1,999,174 Jackson Apr. 30, 1935 2,398,152 Nash Apr. 9, 1946 2,540,679 Laffaille Feb. 6, 1951 FOREIGN PATENTS Number Country Date 541,607 France of 1922