Shoring Scaffold And Formwork Support

Abstract

Relative adjustable roller and rigid support for formwork and scaffolding in which vertically oriented jack screw assemblies disposed either at the top or bottom of a shore member are adjustable to vary the supported height and position of the shore member with either a rolling or rigid contact, or both, with respect to a work area or a weight bearing horizontal or inclined surface. Engagement is also by roller means located at the working ends of jack screws which operate automatically with their level adjustment to hold the rollers against rotation in weight carrying relationship while the formwork is in its elevated position.

Description

BACKGROUND OF THE INVENTION:

Wherever a shore member is to be supported to carry a load with adjustments at its top or bottom for vertical or horizontal positioning with or without relative movement in one or the other directions, more than one shore member is generally required and either the footing or grade for each member has to be accommodated with respect to the other, or the position of a supported construction such as formwork must be adjusted both vertically and horizontally. It is of great convenience to make lateral as well as vertical adjustments with both rolling and rigid contacts and also provide for the application of forces in opposite directions vertically to hold or move a unitary supported load at each support station in proper orientataion.

Furthermore, work scaffolds and formwork are generally moved intact from place to place to perform their functions and it is desired to roll one or the other of them intact between work positions and there rigidly support them at adjusted heights or inclinations for repeated uses.

Although form roll out supports mounted on structural columns of a building under construction have been used and re-used heretofore in a manner involving lowering formwork a short distance onto rollers by which the formwork can be removed intact and re-used for other sections of flooring either co-level with or above the level of their previous use, the working space for handling and adjusting the supports is limited as to height if a bracket itself is to hold the formwork rigidly in place during slab pouring operations. Difficulties in mounting, adjusting, servicing and removing the formwork cause delay and inhibit the use of unitary multi-level forms.

Moreover, in view of the desire for versatility in formwork shapes and depths defining different ceiling levels including various sizes and thicknesses of reinforcements around building columns and equipment receiving wells, column shore brackets heretofore employed have many limitations and shortcomings either in requiring excessive lowering for roll out or not enough for clearance and versatility.

Due to the height of supports and the adjustments for rigidity of the support, special tools are required, female threads become fouled and male threads are difficult to clear of damaging corrosive, fast setting cements. Also, a fixed roll-out level restriction encounters interference and other difficulties that may arise which involve alteration or damage to the formwork in clearing and moving it.

Heretofore, due to their high location and limited clearance relationship, adjustable jack screw mechanisms are mechanically integrated as a part of the whole support assembly whose total weight must be manually lifted when securing and removing it from its support position.

SUMMARY OF INVENTION:

In the present invention a jack screw is provided which can be used at the top or bottom of a tubular support member such as a shore or bracket, to engage and coact with a surface either by rigid or rolling contact selectively at widely adjustable heights, each jack screw assembly with respect to the others and with respect to a load supported thereby.

In the present invention the supports comprise a simple, comparatively inexpensive, and indestructible frame having a vertically oriented tubular element which closely receives in axial telescoping relationship for rigid erectness the outside diameter of a heavy screw member having a heavy or square thread. Weight bearing winged nuts threadedly interengage the screw member and tubular element at the top or bottom, or both, of the tubular member with free running tolerances between the mating threads. No tools are required to make rigid height adjustments when setting up scaffolding or a formwork support level, or when rolling out the formwork intact for reuse.

The frame is fabricated of comparatively light steel forms or plate for installation or removal without the adjustment mechanism being assembled therewith. The adjustment mechanism comprises a jack screw assembly that can be mounted or removed by axial telescopic movement with respect to the tubular element. This movement can be made vertically, or horizontally, into and out of its working position after the frame has been lifted and is being secured in place or being removed. The jack screw in turn carries a winged nut that engages the end of the tubular member in adjustable height and weight bearing relation. The exposed end of the jack screw receives a second winged nut thereon in weight bearing relationship and on its end is mounted a bracket for rigidly engaging a weight bearing surface. A bracket supporting a roller engages the second winged nut and the roller and rigid bracket are moved with respect to each other to place the roller in rolling contact with a weight bearing surface. The wing nuts can be grossly adjusted before the jack screw assembly is separately lifted and disposed in the bracket. Thereafter a workman merely finalizes the adjustment with substantial savings of time in handling both preliminary and final adjustments.

The invention also contemplates means by which floor slab form-work may be pulled downwardly by the jack screws to straighten or lower the formwork involving winged nuts on an exposed lower end of the jack screw.

A further object of the invention contemplates the immediate carrying of the formwork load by a roller that is adjustable as to height for ease of handling the formwork at any predetermined adjustable level even with the roller located at widely variable heights with respect to each other, if desired or required.

Another object and advantage of the invention is the ready interchangeability and adjustment of self contained jack screw assemblies of different lengths for special applications. Additionally, the invention can be used with other vertically disposed tubular supports secured to structural columns and shore members. Also, installation and removal of the jack screw assemblies can be easily accomplished with the aid of a pulley hoist shored by a pole no higher than the bottom of a poured slab located above it.

Other and further objects and advantages will become apparent from the description and drawings which follow including the ease of fabrication of the embodiments shown, simplicity of operation, and servicing and minimized effort to adjust relative positions of parts with minimum friction and effort.

IN THE DRAWINGS:

FIG. 1 is an upwardly directed perspective view showing one of the embodiments of the invention operating to support formwork for a poured concrete floor slab;

FIG. 2 is a perspective view of the support shown in FIG. 1 in an intermediate stage of assembly;

FIG. 3 is a vertical sectional view of the assembled support shown in FIG. 1;

FIGS. 4 and 5 are fragmentary, partly sectional views showing parts of the embodiment in FIG. 1 in alternate operational positions;

FIG. 6 is a view similar to FIG. 3 showing a modified assembly thereof;

FIGS. 7 and 8 are views similar to FIGS. 4 and 5 illustrating a modification of the invention in alternate operational positions;

FIG. 9 is a cross-sectional view of the column taken on line 9--9 of FIG. 6;

FIG. 10 is a sectional view taken on line 10--10 in FIG. 8;

FIG. 11 is a view similar to FIG. 1 illustrating another embodiment of the invention;

FIG. 12 is a perspective view of the support shown in FIG. 11 being assembled;

FIG. 13 is a vertical sectional view of the top portion of the jack screw assembly shown in FIG. 11;

FIG. 13A is partial view of a modification of the screw jack shown in FIG. 13;

FIG. 14 is a vertical sectional view of the assembly shown in FIG. 11 in which the jack screw is employed to strip the formwork;

FIG. 14A is a view similar to FIG. 14 illustrating a modification of the frame shown in FIGS. 6 and 14;

FIGS. 15 and 16 are views illustrating the alternate operational positions of the jack screw assembly shown in FIG. 11 supporting a work or shore scaffold.

THE PREFERRED EMBODIMENTS:

Referring in further detail to the drawings, a concrete structural column 10, of a building that is being built of poured concrete and having vertical reinforcement rods 11 (FIG. 10), is shown in FIG. 1 supporting form-work 12 upon which concrete is poured to form the slab 14 of the next upper floor. After hardening, another series of structural columns will be formed on the slab 14 and the formwork illustrated will be lowered and rolled out intact in a horizontal direction and rigidly relocated on the new columns for reuse in forming the next slab above slab 14, etc.

Although the frame of the formwork may include "I" beams as shown in FIG. 11, timbers 16 are shown in FIG. 1 by way of simple illustration with formwork plywood panels 18. The column 10 is one of many that are spaced and aligned in parallel rows in a repetitive pattern with each having spaced tubular elements 20, or ty-lags, embedded in them and receiving removable bolts or studs 22 therethrough to accept nuts 26 thereon that clamp the frame portion 23 of the support 24 to receive and support the jack screw assembly 25, upon which the formwork is removably supported at an adjustable height.

The frame 24, sometimes referred to as a bracket in the trade, comprises a section of a T-beam 27 or fabricated parts (FIG. 14) with a tubular member 32 welded thereto along the edge of the leg portion 34 and with right triangular braces 36 welded in the corners between the arms 38 and leg portion 34 at either or both ends of the T-beam section with stamped out slots 37 for ease in handling. The arms 38 provide a base portion 30 to engage the column 10 in supported relation.

The base 30 has a pair of horizontally spaced holes 28 adjacent either or both ends of the T-beam section or vertically spaced holes 28A (FIG. 14A) located between reinforcement rods to receive through the uppermost pair thereof the threaded ends of the studs 22. Although the frame 24 may be secured by two or four studs with either end up, it preferably is disposed with the braces 36 downwardly where they may serve as handles during installation, adjustment and removal. Generally only two studs are employed. The nuts 26 on the studs 22 when tightened clamp the base against the column at a height, and, as later discussed, the jack screw can be mounted in place between the times of application of the two nuts.

The tube 32 has cylindrical opening 40 therethrough and telescopically receives therein a jack screw 42 having external longitudinal undulations thereon such as a rack, or as shown, a square coarse helical thread 41 for relative vertical adjustment. Preferably the jack screw is more than twice the length of the tube 32 with the thread either ending or obstructed at a point 46 spaced from the lower end of the jack screw a distance substantially equal to the length of the tube 32. The lower end of the jack screw 42 if cylindrically smooth fits with the tube and also substantially reduces thread contamination from the bottom of the tube.

In FIG. 14A the tube 32 is supported by two parallel side plates 34A and an apertured cap plate 74A that are welded to a vertically elongated base 30A having vertically spaced holes 28A.

At its upper end the jack screw is of reduced size as later described and, as shown in FIGS. 1-3, carries a saddle member 48 that preferably is loosely but squarely engaged by the upper end of the screw 42 and has a cradle defining a frictional surface 50. Coacting to hold the saddle in operative position is a roller 52 journalled on an axle 54 supported at its ends by the upright arms 56 of a U-shaped member 58 whose bight 60 is apertured at 63 and secured to a depending collar 62. The axle 54 is a headed pin secured in place by a cotter key 55 and the collar has diametrically opposed axially elongated slots 64 slidably receiving the ends of a pin 66 carried by the bolt as also secured in place by a cotter key 68. Thus, the collar 62 and roller are axially movable with respect to each other to move the saddle 48 in and out of frictional engagement with the roller 52.

For this purpose a camming device engaging the thread undulations 41 such as a winged nut 70 having its hub 76 threadably received on the screw 42 has on its opposite sides weight-bearing, friction-reducing washers 72 and 74 which engage the lower end of the collar 62 and the upper end of the tube 32, respectively, in a weight bearing assembly whereby the load of the formwork carried by the roller 52 is transmitted at all times through the hub of the winged nut 70 to the upper end of the tube 32.

Although a longitudinal keyway can be cut through the thread turns to engage a key in the tube to prevent relative turning of the screw assembly, it has been found that the pins 66 further coact with the high arms of the U-shaped member 58 to prevent rotation of the jack screw when the nuts 70 and 70A are being adjusted. The arms engage the sides of the beam timbers 16 or I-beam 16A (FIG. 11) and provide the anti-rotation control.

With the winged nut 70 resting on the end of the tube 32 in FIG. 3 it is to be noted that the load of the beam 16 or 16A carried by the rollers 52 at all times is assumed by the saddle when the nut 70 is turned to raise the screw to adjust the height of the roller. The saddle in turn transfers the roller load directly to the screw 42 for a friction establishment that prevents rotation of the roller and thereby prevents movement of the formwork while the concrete is being poured. The load is therewith carried by the threads 41 to the nut to the tubular member 32. Thereafter when the reverse rotation of the nut 70 bottoms the collar 62 on the nut the U-member 58 carries the load directly to the nut 70 and the roller is free to roll out the timbers. In the embodiment shown in FIG. 3 having a single dual-wing nut, the roller is only free to roll when the screw 42 is in its lowest position.

A modification demonstrating versatility is shown in FIG. 6 in which the same parts described are used with a second wing nut 70A added on the screw 42 to frictionally brake and release the roller at any determined adjustable level. In this embodiment, when adjusting to support the formwork, the nut 70A, and nut 70 also, if necessary, is turned until the roller 52 frictionally rests in the cradle 50. Thereafter advancement of the nut 70 locates the braked roller 52 at its working level with the timbers 16 resting thereon. After the poured slab 14 hardens, the nut 70A is reversely turned a few turns until the roller 52 is free and then the nut 70 is reversely turned until the desired roller roll-out level for the formwork is attained.

Referring now more specifically to the embodiment shown in further detail in FIGS. 11-16, the tubular element 20 is welded to the edge of the leg portion 34 of a formed section 27 while the tubular element 20A in FIGS. 15 and 16 constitutes the lower end of one of the shore legs 27 of a shoring scaffold upon which work or workmen are supported at a level above a surface or floor 31. In both embodiments the tubes 10 and 10A have like cylindrical openings 30 therethrough and telescopically receive the jack screw 42 with the winged nut 70 in loosely threaded relationship engaging the tube end in weight bearing relationship.

The embodiment shown in FIG. 14 is similar to the embodiment shown in FIG. 3 except that the collar 62A may be pinned without lost motion to the reduced end 43 of the jack screw and the saddle 48 of FIG. 3 is reshaped to provide a rigid support 50.

Although the winged nut 70A may actuate the roller 52 and the rigid support 80 be engaged by the shaft 42 for relative movement between the two for selectively engaging either the formwork beam 16A (FIG. 14) or the floor 31 (FIG. 15), the embodiment shown is one in which the rigid support 80 comprises a yoke-like member having the upper portions 82 of the vertical sides 83 of a U-shaped member flattened outwardly to a common plane to provide a flat frictional engagement of the beam 16A or floor 31 with the bight portion 78 thereof preferably supported by the winged nut 70A in its extended position.

The roller 52 is preferably received reciprocably between the sides 83 as journalled on the axle 54 that is carried by upstanding arms 56 of the U-shaped member 58 whose bight portion may be welded as at 25A (FIG. 13A) to the shaft 42 directly or is apertured at 57 and welded as at 59 to the collar 62 concentric therewith (FIG. 13) to telescope over the end 65 of the shaft 42 for the bight portion 60 to be carried by the end 65 of the shaft as secured thereto by the pin 66 without any lost motion in weight bearing relationship. The sides 83 are close enough to the roller 52 to hold it against lateral displacement in its reciprocable movement.

The optional use of a third winged nut 70B is illustrated in broken lines 70B in FIG. 14 on the lower end of the jack screw 42 to engage the lower end of the tube 32 if desired in conjunction with a C-clamp 84 that secures the lower flange 17 of the I-beam 16A to the upper portions 82 of the yoke. With this arrangement formwork can be stripped from the concrete slab 14 if it does not drop free as the winged nut 70A is retracted.

In the operation of the embodiments in FIGS. 1-10 as formwork supports, once forms are removed from the poured structural columns 10 exposing the tubes 20 embedded therein the support frames 24 are easily lifted and mounted on one bolt 22 preferably without the jack screw assembly 25 in place as yet. Thereafter with the tube 32 turned horizontally the jack screw is adjusted for gross extension, lifted and horizontally slipped into the opening 40 whereupon the frame and its tube is returned to its upright position to erect it and the winged nut 70 moves into weight bearing relation with the tube 32. The other one of the bolts 22 is then inserted through the other hole and both nuts 26 are then tightened to clamp the base 30 solid against the wall of the column 10. The jack screw assemblies are then given their final adjustment for the formwork support level. After the floor slab 14 is poured and sets, the reverse of the installation steps is followed to remove the jack screws, the frame and the bolts for reuse installation on floors above.

In operation and referring to FIGS. 11-16 the jack screw assembly is adjusted with the winged nut 78 advanced to extend the upper portions 82 beyond the roller 52 as shown in FIG. 13 whereupon the winged nut 70 is adjusted to gross height and the screw 32 dropped into place as shown by the arrow A in FIG. 12, the winged nut 70 comes to rest on the tubular member, as shown in FIG. 11. Thereafter the winged nut 70 is fine adjusted to locate the elements 82 at a predetermined height for supporting the formwork beam 16A thereon.

In all embodiments when the formwork is to be rolled out the winged nut 70 is rotated to lower the member that contacts the beams 16 or 16A to a predetermined level and the winged nut 70A, where present, is rotated to place or free the roller 52 for rolling contact with the beam or floor as shown in FIGS. 3, 8, 9 and 15. After the formwork is rolled out the jack screw assembly can be lifted free if desired and the frame 23 removed for use in another location.

The ability of quickly separating the weight loads of the frame 33 and screw assembly 25 of the support 24 into two parts for handling and the slipping of the jack screw either horizontally or vertically into its working position, saves work, time and effort for labor and servicemen under what would otherwise be adverse conditions. Also, the simplicity of construction is self-instructing in its operation and contributes to safety in installation and use.

It is to be also noted that more often than expected, jack screws become damaged in use and may require attention that cannot be given while mounted in place, and the whole assembly heretofore has had to be removed. With the present invention, both bolts may be loosened and one removed. The frame is then tilted to drop out the damaged jack screw assembly and replace it with another one with the frame again quickly tilted back, tightened in place and the roller adjusted as to height.

Moreover, it will be observed that the support 24 lends itself to knockdown shipping and servicing. Removal of cotter keys and turning the winged nuts enables finger disassembly and assembly of all parts for repair or replacement at the building site with little if any delay in a building program if a spare jack screw assembly is not available. Moreover, all threads can be cleaned of concrete debris. The saddle 48 is a loose element in the assembly, as geometrically supported operatively in the bight of the U-shaped member by the roller 52 for coaction with the upper end 43 of the jack screw 42 slidably received in the collar 62.

The dimension of interest for this purpose is the distance indicated by the dotted arrows 63 in FIGS. 3 and 6. This distance between the corner 53 and the curve of the frictional surface 50 is greater than the maximum adjusted distance between the roller 52 and bight 60.

For the installations of one or more wing nuts, the upper end 43 of the jack screw can either have the thread 41 extended to the saddle or it can be of a diameter reduced to the minor diameter of the thread as at 65 (FIGS. 7, 8, 13 and 14) so that the nuts 70 and 70A can pass thereover.

Referring to FIGS. 4, 5, 7 and 8, it is optional whether the slots 64 accommodating lost motion of the pin 66 are in the collar 62 or the upper end 43 of the shaft. In both alternatives the tensional downward pull on the pin 66 squares and holds the collar against the wing nut 70 as at 61 while an upward end thrust by the jack screw 42 against the saddle 48 provides the deepest of the two alternate telescopic guided engagements between the parts for lateral support. Both, however, eliminate any weight strain of the formwork on the pin 66. In the embodiment illustrated in FIG. 13 the tensional downward pull of the collar 62 is utilized as already mentioned to strip the formwork, if necessary, by the use of the winged nut 70B when winged nut 70 relinquishes contact with the tubular member 32 when loosened.

Claims

What is claimed:

1. A roll out support for formwork used intact to form and cure successively a plurality of concrete floor slabs at spaced locations, said support comprising,

a frame having a base portion to engage a structural column and a vertically disposed tubular element spaced from said base above a work area and having an end bearing at its upper end,

releasable means separately securing the frame base portion to said column at horizontally spaced locations for relative movement of the frame about one location with respect to the other to movably dispose said tubular means horizontally,

jack means including a screw telescopically received rotatably in said tubular element with heavy external threads thereon in rigid radial supported relationship over a lower end portion thereof,

a first manually controlled nut means threadably carried by the screw intermediate its ends to releasably bear against said end bearing in screw supporting height adjusting relation,

a second manually controlled means threadably carried by the screw adjacent its upper end through which the screw member extends an adjustable distance,

a first member carried upon the upper end of said screw in weight supporting relationship,

a second member carried upon the upper end of said screw in telescoping relationship therewith in weight supported contact with said second manually controlled means for relative movement with respect to said first member,

roller means carried by one of said members, and

rigid weight supporting means carried by the other of said members.

2. The combination called for in claim 1 in which said rigid weight support means interengages said second member and the roller means to arrest rotation thereof.

3. The combination called for in claim 1 in which said rigid weight supporting means and roller means are disposed approximately the same height at a relative point intermediate the limits of said relative movement between said members.

4. The combination called for in claim 1 in which said screw extends below said tubular element when said first nut means is retracted, and

said rigid means including means for securement to formwork supported thereby.

5. The combination called for in claim 1 in which an upper end portion of said screw is of reduced diameter and said first member includes a collar element carried by said upper end portion.

6. The combination called for in claim 5 including a lost motion device between said screw and said first member.

7. The combination called for in claim 6 in which said roller means is carried by said second member.

8. The combination called for in claim 1 in which said roller means is carried by said first member.

9. In a device of the class described, the combination of a plurality of vertically oriented horizontally spaced work support tubes,

jack screw means telescopically received in at least two of the support tubes,

winged nut means threaded on the upper ends of the threaded elements and engaging said tubes in adjustable weight bearing relationship, and

roller means supported with their axes of rotation parallel and disposed normal to the axis of each of said threaded elements,

brake means disposed to one side of each roller means,

position controlling means supporting one of said last two means for relative vertical movement with respect to each other for alternately engaging a weight bearing surface and including

a winged nut on each threaded member supporting one of said means and the other one of said means being carried by said threaded elements.

10. In a device of the class described for detachable mounting on a vertical member employed in supporting floor slab formwork, the combination of a support frame having a base member with laterally spaced holes and vertically oriented tube means having an end bearing spaced a predetermined distance above a work area,

means for supporting said base member to said vertical member at each of said holes, and

a jack means freely received telescopically in said tube means in weight supported relationship, said jack means including,

a. a screw member telescopically received in said tube means having radially extending thread elements spaced axially along its surface, said thread elements at their major radial dimension engaging said tube means in rigid erecting relationship,

b. cam nut means threadably received on the screw member intermediate its ends to weight bear against said end bearing in screw supporting height adjusting relation to move the sleeve elements upwardly and downwardly predetermined distances in supporting relation,

c. bracket means supported upon the upper end of said screw member having a collar means resting against said cam nut means in a lower position,

d. roller means carried by said bracket means to engage form-work to be supported,

e. lost motion means interengaging said bracket means and said screw member in supported relation for relative movements between limits,

f. brake means between said screw member and roller means actuated by said screw member intermediate the limits of said lost motion means to engage and support said roller means and the load carried thereby,

said cam nut means drawing said bracket means in square supported relation against said cam nut means at the other limit of said lost motion.

11. The device defined in claim 10, said screw member having an upper end reduced to a diameter not exceeding the inner diameter of said thread elements and telescopically supporting said bracket means in axial alignment, and

stop means on said thread elements at a distance from the lower end of said screw member that is substantially the length of said tube means.

12. In a device of the class described, the combination of a plurality of vertically oriented horizontally spaced tubular work support means having upwardly directed end bearings located above a work space on a floor,

jack means telescopically received in the support means having radially extending undulations spaced axially along its surface, the major radial dimension of which internally engage said support means in telescopic rigidly erected relationship,

manually controlled retainer means carried by said jack means resting on said end bearing and movable progressively to engage successive undulations to move the jack means upwardly and downwardly predetermined distances in weight supported relationship on said end bearing,

roller means to engage an object to be supported in rolling relationship,

lost motion means interengaging said roller means and said retainer means in supported relation,

means actuated by said retainer means to arrest rotation of said roller means and support the load carried thereby.

13. The device defined in claim 12 in which said jack means is a screw having a coarse thread and an upper end of a diameter reduced to approximately the inner diameter of said thread and telescopically supporting said bracket means in axial alignment,

said lost motion means including an elongated slot element and a pin element with one element on said jack means and the other element on said roller means to prevent relative rotation therebetween, and in one position of adjustment squaring said roller means against said retainer means.

14. The device defined in claim 12 in which said brake means includes a saddle member interengaging said jack means and said roller means when said lost motion means is extended by said retainer means.

15. The device defined in claim 12 in which said retainer means comprises a plurality of winged cam members, one engaging said end bearing and the other the roller means.

16. In a device of the class described for fixedly supporting and rolling two objects with respect to each other in weight supported relation at different levels, one object of which has a tubular vertically oriented member, the improvement comprising,

jack screw means including a rotatively adjustable shaft means telescopically received in said tubular member for close axial alignment at one of its ends and having a heavy weight bearing thread intermediate its ends,

nut means carried by the shaft means in threaded relationship intermediate its ends for engaging the tubular member in screw supporting adjustable relation with respect thereto,

bracket means engaging said jack screw at the other one of its ends and including lost motion means interconnecting them against relative rotation and limiting their relative extension,

roller means supported by said bracket means to engage the other one of said objects,

brake means intermediate the said other end of said jack screw and roller means for restraining said roller means against rotating under weight bearing conditions between the limits of said lost motion means,

said limit of relative extension of said lost motion means disposing said bracket means in squared weight transmitting relationship with the roller means through said nut to said tubular means.

17. The improvement defined in claim 16 in which said roller means includes a roller and an axle releasably journalling said roller on said bracket means,

said brake means comprising a saddle member having a face engaging said roller means and a radial dimension greater than the major distance of the roller means from said jack screw at said extension limit.

18. The imvprovement defined in claim 16 in which said other end of said jack screw is of a diameter reduced at least to the minor diameter of said thread for reception of said nut thereover in concentrically supported relationship, and

stop means for said nut means on said thread at a distance from said one end of said jack screw that is substantially the length of said tubular member.

19. The improvement defined in claim 16 in which

said brake means defining a substantially hemi-cylindrical surface matching the surface of said roller.

20. A roll out support for formwork used intact to form and cure successively a plurality of concrete floor slabs at spaced locations, said support comprising,

jack means including a screw having heavy external threads and supporting at one end a vertically movable roller on one end,

manually adjustable nut means carried by the screw intermediate its ends, and

frame means including a narrow base plate to engage on one side the wall of a structural building column and having spaced apertures to receive a removable support means engaging said column,

two vertically disposed horizontally spaced side plates secured to the other side of the base plate, and

tubular means secured between said side plates to be disposed vertically to receive the other end of said screw telescopically and rotatively therein and having a cap element rotatably engaging said nut means in supported relationship.

21. In a device of the class described for detachable mounting on a vertical member employed in supporting floor slab formwork, having a support frame having a base member and means for securing said base member to said vertical member in supported relation, the combination:

a vertically oriented tube means on said frame having an upper end spaced a predetermined distance above a work area; and

jack means supported on said tube means including

a. cam nut means supported on said tube means,

b. a screw member telescopically received in said tube means having radially extending thread elements spaced axially along its surface engaging said cam nut means in adjustable supported relation for relative movement upwardly and downwardly in erect position,

c. roller means carried by the upper end of said screw member in weight bearing relation with the roller disposed in a horizontal position,

d. rigid weight supporting means received on said screw member below said roller means and telescoping therewith in an axial direction to extend above said roller means in its uppermost position,

e. winged nut means carried by the screw below said rigid supporting means to move said rigid supporting means into weight bearing relationship above said roller means, and

f. means for manually rotating said screw member and cam nut means with respect to each other to bodily raise and lower said rigid supporting means, roller means and winged nut means.

22. The combination called for in claim 21 in which said rigid weight supporting means and roller means are disposed approximately the same height at a relative point intermediate the limits of said relative movement between said members.

23. The combination called for in claim 21 in which said screw member extends below said tube means when said cam nut means is retracted, and

said rigid means including means for securement to formwork supported thereby.

24. The combination called for in claim 21 including a lost motion device between said screw member and said rigid means.