US2949982A

US2949982A - Form jacks

Info

Publication number: US2949982A
Application number: US842122A
Authority: US
Inventors: Walter H Cobi
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-09-24
Filing date: 1959-09-24
Publication date: 1960-08-23
Anticipated expiration: 1977-08-23

Description

w. H. coal 2,949,982

FORM JACKS 2 Sheets-Sheet 1 Aug. 23, 1960 Filed sept. 24, 1959 INVENTOR.

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w. H. coBl Aus. 23, 1960 FORM JACKS 2 Sheets-Sheet 2 Filed Sept. 24, 1959 NN 9 INN E. mm/ a fair.

R.i 0b /a wow ECM V NH Ir f m a M W e M, s y o.

ATTORNEYS 2,949,982 Patented Aug. 23, 1960 FORM JACKS Waiter H. Cobi, 45 Upland St., Port Chester, NX.

Filed Sept. 24, 1959, Ser. No. 842,122

Claims. (Cl. 189-37),

The present invention relates to devices for supporting concrete form boards between spaced floor joists and more particularly to improvements in devices of the type illustrated and described in my U.S. Letters Patent 2,866,252, issued December 30, 1958, and entitled Concrete Form Holders.

lt is a common practice in building construction to lay oors of reinforced concrete on floor joists mounted in spaced relation between the main load bearing beams of the building structure. Such joists are usually solid or open web metal I-beam. Ply-Wood form boards are mounted between the upper flanges of the joists to provide a temporary door for the buggies in which the wet concrete is transported and provide a support for the poured concrete until it has set. After the boards have been mounted between the upper iianges of the I-bearn joists, a mat of reinforcing rods is placed over the top of the joists and form boards. After the concrete has set, the plywood forms are removed leaving the reinforced concrete slab supported on the joists to form the floor.

My Patent 2,866,252 illustrates and describes a collapsible form-jack for supporting the ply-wood form boards which may be easily and quickly applied to and removed from the I-beam joists with which they are used. The form-jackets extend between the joists with their ends supported by the lower flanges thereof and each jack com prises separate built-up beam sections having overlapping inner ends pivotally connected to each other. Thus, the built-up beam sections of the form-jacks may hinge to adapt the jacks to be inserted between the joists. After a form jack has been positioned between spaced joists, the built-up beam sections are rocked into horizontal alignment and locked by pins inserted in aligned slots in the upper edges of the overlapping sections. Load bearing pads are mounted on the sections of the form-jack adjacent its ends which project upwardly therefrom and support the form boards. Such form-jacks have been used extensively and have proved to operate satisfactorily.

One of the objects of the present invention is to provide an improved form-jack of the type indicated which facilitates the insertion and removal ofthe jack to and from the joists with which it is used.

Another object is to provide a form-jack of the type indicated which is adapted to hinge intermediate its end upon the manual application of a force at its opposite ends -to adapt the jack to be inserted between the ilanges of spaced joists and spring back to its extended position when released.

Another object is to provide an improved construction in a form-jack which faciiitates locking the jack in its operative position between joists and unlocking the jack to permit it to hinge.

Another object is to provide a form-jack of the type indicated having a minimum number of interchangeable parts and which may be easily and quickly adjusted to iit joists of different heights and spacings.

Still another object is to provide a form jack of theY type indicated which is of simple, compact, rugged and light-weight construction and one which is economical to manufacture and reliable in operation.

These and other objects will become more apparent from the following description and drawings in which like reference characters denote like parts throughout the several views. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings:

Figure 1 is a side elevational View partly in section of a form jack incorporating the novel features of the present invention and showing the relationship of the parts When the jack is locked in position between spaced joists to support a form board;

Figure 2 is a plan View of the form-jack partly in section and showing the pivoted sections of the upper strut connected by a flexible spring strip;

Figure 3 is a bottom plan view of the spring strip connecting the sections of the lower strut and showing the key hole which cooperates with the locking bar.

Figure 4 is a transverse sectional view taken on line 4 4 of Figure l and showing the inverted U-shaped form of the load supporting stanchion at one end of the jack and the manner of mounting the strut sections therebetween;

Figure 5 is a view similar to Figure l showing the formjack hinged intermediate its ends to adapt it to be mounted between the spaced joists;

Figure 6 is a view similar to Figure 5 and showing the manner in which the form-jack is locked in extended position between the joists;

Figure 7 is a view similar to Figure 6 showing the locking bar in unlocking position and being pulled to remove the jack from the spaced joists;

Figure 8 is a side elevational view of one end of the jack shown applied to an open web joist and an adapter for adjusting the height of the stanchions for beams of different heights; and

Figure 9 is a transverse sectional view taken on line 9-9 of Figure 8 to show the manner of mounting the adapters on the stanchions.

Referring now to the drawings, Figure l illustrates a reinforced concrete floor construction and the form-jack of the present invention. The door construction comprises spaced lloor joists 1d and 143', only two being shown, which are supported at their ends on the load carrying beams of the building structure, not shown. The

joists

10 and 10 may be of the solid web i-beam type, as shown in Figures 1 to 7, or of the open web type illustrated in Figures 8 and 9. In either case, the joists 1i) and. 10 each have upper and lower anges il and 12 and the joists are spaced from each other a predetermined fixed distance, for example, 24 inches on centers. A form board 13 is shown supported between the spaced floor joists l0 and 10 by form-jacks 14 constituting the subject matter of the present invention. Preferably, the form board 13 extends under the flanges 11 of the

joists

19 and 10 as illustrated in Figure l, to reduce the dripping of wet concrete and the board, for example, may be twentytwo inches wide and from four to eight feet long and overlaps the flanges about one-half inch. Overlying the top of the form boards 13 and top ilanges 11 of the joists titl and 10 is a mat 15 of reinforcing steel mesh immersed in a concrete mass 16 poured on the form boards and joists to form a oor.

Each form-jack 14 comprises

upright stanchions

17 and 18 at each end with upper and

lower struts

19 and 20 extending therebetween and a locking bar 21 extending through the struts.

Struts

19 and 20 are adapted to hinge when released by the locking bar to collapse the jack for insertion and removal, but may be locked in spaced relation by the locking bar. When the struts are locked in spaced relation, they act against each other to resist bending and ycollapse of the form-jack. ln other words, when the hinge portions of the struts 19 and 2) are held in spaced relation they cannot buckle relative to each other. In the illustrated embodiment, the struts 19 and 2@ are shown substantially parallel when in locked position, but they may extend at an `angle to each other or at other angles to the stanchions 17 and 1S than the 90 angle illustrated.

As shown in Figure 4, each upright stanchion 17 and 1S is in the form of an inverted U-shaped yoke having spaced

parallel sides

22 and 22a with a connecting top plate 23 and outwardly projecting

anges

24 and 25 at the lower ends of the sides. A base plate 26 underlies the

flanges

24 and 25 of each stanchion 17 and 1S and is attached thereto `as by means `of bolts 27. Each base plate 26 projects outwardly beyond its

stanchion

17 and 18 to provide a foot 28 adapted to rest on the lower iiange 12 of the

door joists

10 or 10. Base plates 26 of diiferent length may be attached to the

stanchions

17 and 18 to accommodate the iiange 12 or" particular floor joists and 16. The transverse top plates 23 of the inverted U-shape stanchions 17 and 1S provide spaced supports for the form board 13 adjacent each end of the form-jack. The

sides

22 and 22a of each stanchion 17 and 1S have aligned

holes

36 and 75 oiset both vertically and laterally for a purpose as will later appear.

The upper strut 19 comprises separate

rigid sections

29 and 36 pivotally connected at one end to the respec-`

tive stanchions

17 and 18. In the illustrated embodiment, each

rigid section

29 and 36 is in the form of a channel having a web 31 extending between the spaced sides 22.

and 22a of stanchion 17 or 1S and depending ilanges 32 and 33 adjacent the sides. The

flanges

32 and 33 of

rigid channel sections

29 and 30 have a series of aligned

holes

34, 34', 34, etc., spaced at ixed increments from one end corresponding to usual increments of spacing between joists 1t) and 16. 30 is pivotally connected to its stanchion 17 or 1S, respectively, by a pin 35 extending through aligned holes 36 in the

sides

22 and 22a of the stanchion and one set of aligned

holes

34, 34', 34, etc., in

anges

32 and 33 of a strut section. As shown in Figure 4, the pin 35 is staked adjacent one end to provide a lug 37 for engaging one side 22 of the stanchion and a spring clip 38 is mounted on the other end of the pin for engaging the other side 22a of the stanchion to hold the pin in position. This construction permits the pins 35 to be removed for adjusting the length of the form-jack when required. The inner ends of the

rigid sections

29 and 30 of upper strut 19 are connected by a spring hinge illustrated as a strip of spring material 40 attached to webs 31 of the

rigid sections

29 and 30 by rivets 41. Strip 40 yieldingly holds the

sections

29 and 30 in horizontal alignment but yields to adapt the strut 19 to hinge intermediate its ends. The spring strip 40 may be formed of any suitable material such as spring steel.

The lower strut 20 is of a construction similar to the upper strut 19, but reversed thereto, and comprises

rigid sections

42 and 43 of channel form positioned between the sides of the

upright stanchions

17 and 18 below the upper strut 19. Each rigid section 42.and 43 of the lower strut is connected to its

respective stanchion

17 or 18 by a plurality of

pins

44 and 45 of the same construction as the pin 35 and removably secured to the stanchions by lugs 37 and a spring clip 38. Thus, the

rigid sections

42 and 43 can move only as a unit with the

stanchions

17 and 18 to which it is connected. The inner ends of the

rigid sections

42 and 43 of the lower strut 20 also are connected to hinge by a spring strip 46 attached to the section by means of rivets 47. Thus, the spring strip 46 yieldingly holds the sections 42 and Each rigid section 29 and- 43 of the lower strut 20 in alignment, but yields to permit the strut to hinge intermediate its ends.

In the form-jack 14 illustrated, the inner ends of the

rigid sections

29, 30 and 42, 43 of each

strut

19 and 20 are spaced apart ive inches and connected by a spring steel strip nine inches long, three inches wide and one thirty-second of an inch thick and overlaps the sections two inches with the rivets spaced one inch apart. It will also be observed that the

stanchions

17 and 18 at each end and the upper and

lower struts

19 and 20 are identical, brut reversed, so that the parts are interchangeable.

The

spring lstrips

41 and 46 of

struts

19 and 20 are held in substantially parallel relation to each other or released for hinging movement by the locking bar 21. The locking bar 21 is illustrated in the form of a rod extending through

holes

50 and 51 in the spring strips 46 and 46, respectively. The hole 50 is of circular form to Y closely t the locking bar 21, but the hole 51 in the strip of spring strips 4l) and 46.

46 has a slot 52 at one side to provide a key hole for releasing the locking bar 21 as will later appear. Locking bar 21 has shoulders overlying the opposite sides In the illustrated embodiment the shoulders are in the form of

pins

53 and 54 extending through the locking bar 21 in parallel relation at opposite sides of the spring strip 40, a pin 55 extending through the bar parallel with

pins

53 and 54 and overlying the underside of the spring strip 46 and a shorter pin 56 overlying the top of spring strip 46 and projecting from one side of the locking bar at right angles to the

other pins

53, 54 and 55 and of a length to tit and move through the slot 52 at one side of the key hole S1.

Locking bar 21 also has an actuating pin 57 extending through the bar in spaced relation to the lower spring strip 46. Thus, when the locking bar 21 is moved to the locking position illustrated in Figure l, the

pins

53, 54 and 55 extend longitudinally of the

struts

19 and 26 and the shorter pin 56 extends at right angles to the other pins at opposite sides of the spring strips 46 and 46, respectively. On the other hand, when the locking bar 21 is turned 90 from the position illustrated in Figure l to the position illustrated in Figure 5, the pins 53 54 fr, and 55 are positioned transversely of the strip and the shorter locking pin 56 is aligned with the slot 52 at the side of the key hole 51.

Figures 8 and 9 illustrate the form-jack 14 applied to an open web type of joist 59 and adapter pads 66 whichv may be mounted on the stanchions to adjust their height. The open web joist as illustrated in Figures 8 and 9 comprises an upper pair of angle iron strips 61 and 62 and a lower pair of rod 63 and 64 with the reverse bends 65 and 66 of a longitudinally extending sinuous rod 67 positioned between the pairs of upper strips and lower rods and attached thereto as bywelding. Thus, the pairs of angle iron strips 61 and 62 and rods 63 and 64 constitute the flanges of the joist 59 and the sections of the longitudinally extending sinuous rod between the reverse bends and 66 constitute bracing struts between the pairs of angle iron strips and rods and provide an openl web. As shown in Figure 8, an auxiliary foot plate 68 is bolted to the foot 26 of an upright stanchion 17 of the form-jack which overlies and rests on the lower r rods 63 and 64 and the stanchion supports a form board 13 under the horizontal flange of an upper angle iron,

strip 62. Advantageously, the auxiliary foot plate 68 has a hole 69 overlying the space between rods 63 and 64 and through which a spike or bolt may be dropped to releasably lock the jack to the joist.

When a solid web or

open web joist

10 or 59 is used of a height greater than the height of the

stanchions

17 and 18, adapter pads 60 are provided for adjusting the'- height of the stanchions. As shown most clearly in Figure 9, the adapter pads 60 are of inverted U-shaped

form having sides

70 and 71 of a width to t over the' sides 22 and 22a of the stanchions and a weight bearing cross-piece 72 for supporting a form board 13. The

sides

70 and 71 of adapter 60 have aligned

holes

73 and 74, `adapted to align with the

holes

36 and 75 in the sides of the

stanchions

17 and 18 and similar holes 73' and 74' oiset vertically from

holes

73 and 74. The pin 35 for pivotally mounting its section of the upper strut 19 extends through the hole 73 or 73' and a pin 76 extends through holes 74 lor 74' and the holes 75 in the sides of the stanchion to iixedly attach the adapter pad to the stanchion. By positioning the

different holes

73, 74 or 73', 74 in alignment with the

holes

36 and 75 in the sides of the

upright stanchion

19 or 20, the height of the stanchion may be increased in increments corresponding to the increments of increase in the height of the joist used, as for example, l() and l2 inch joists. One form of the invention having now been described in detail, the mounting of the jacks in position between joists or 59 is next explained.

For any particular building the joists 10 and 10' will be of a particular height and the joists will be spaced a particular distance. For example, the joists may be eight, ten or twelve inches high, and the joist may be spaced apart from twenty-four to thirty inches. Each of the form-jacks 14 to be used on the job is adjusted for these articular specications. To this end, the height of the

stanchions

17 and 18 are adjusted when required by mounting adapters 60 thereon at the proper height by inserting

pins

35 and 76 through the

proper holes

73, 74 or 73', 74', see Figure 9. The length of the jack 15 is adjusted by changing the position of the

stanchions

17 and 18 along the

struts

19 and 20 by removing the

pins

35, 44 and 45 and inserting them through the

particular holes

34, 34', 34", etc., in the

anges

32 and 33 of the

rigid channel sections

29, 30 `and 42, 43. Base plates 26 of the proper dimensions also are bolted to the

flanges

24 and 25 on the

stanchions

17 and 18 so as to support the form-jack on the anges 12 of the

particular joists

10 or 59. When the form-jacks 14 are so adjusted they will support the form boards 13 at the desired height between the anges 11 of the I-

beam joists

10 or 59.

Each form jack 14 is mounted between

joists

10 or 59 by turning the locking bar 21 so that the locking pin 56 is in alignment with the key hole slot 52 and positioning the foot 28 of one stanchion 17 on the lower ange 12 of one of the joists. The opposite stanchion 18 is then manually tilted toward the stanchion 17 to cause the jack to hinge intermediate its ends as illustrated in Figure 5. During such tilting, the spring strip 46 of the lower strut exes between the rigid sections 4-2 and 43. However, to permit such flexing the stanchion 18 must tilt inwardly toward the stanchion 17 so that the hinge pins 35 will be spaced a horizontal distance less than the distance between the pins 44. Thus, the upper strut 19 must hinge to a greater degree than the lower strut 20 as illustrated in Figure 4 and such relative movement of the struts is permitted by the pivot pins 35 and the free movement of the locking bar 21 relative to the lower strut. The relative tilting of the

stanchions

17 and 18 permits the foot 28 of the right hand stanchion 18 to pass by the upper flange 11 of the opposite joist 10'. After the foot 28 passes the ange, the stanchion 18 may be manually released and the spring strips 40 and 46 will spring back to their initial position and move the

struts

19 and 20 to substantially parallel relationship to engage the foot 28 of stanchion 18 with the flange 12 of the joist 10' as illustrated in Figure 6.

The jack 14 is then locked in its operative position between the

joists

10 and 10 by raising the locking bar 21 with the locking pin 56 in alignment with the key hole slot 52. This operation is shown being performed manually in Figure 6, but it will be understood that it would be performed by an extension pole or may be performed from above by a man standing on the top of the

oor joists

10 and 10. The locking operation is completed by moving the locking bar 21 from the position illustrated in Figure 6 6to that illustratedin Figure l with theV locking pin 56 moving through the key hole slot 52 to overlie the spring strip 46 and then turning the locking bar through an angle of The

pins

53 and 54 on the locking bar then extend longitudinally on opposite sides of the spring strip 40, the pin 55 extends longitudinally along the underside of the spring strip 46 and the shorter locking pin 56 eX- tends transversely of the spring strip 46 at the top thereof.

When locking bar 21 is in locking position, the upper and

lower struts

19 and 20 are positively held in parallel relation which prevents the jack from hinging intermediate its ends. If a force couple is applied to the'

upright stanchions

17 and 18, tending to hinge the jack 15 between its ends, a compressive force is produced on one

strut

19 or 20 and a tension force is produced on the other strut. Thus, a compressive force on the upper strut 19 tending to buckle the strut is transmitted through the locking bar 21 to the other lower strut 20, which is in tension, and opposes the buckling of the upper strut. As stated above, one of the struts, such as the upper strut 19, must buckle and move relative to the other lower strut 20 before the jack 14 can hinge intermediate its ends and the pivot pins 35 for the upper strut must move toward eachother, but such relative movement of the

struts

19 and 20 is prevented by the locking bar 21 which holds the struts in parallel relation. Thus, the

struts

19 and 20 act as rigid members when locked by the locking bar 24.

After a series of the form jacks 14 have been mounted between the floor joists 10 and 10 and locked in place, the form boards 13 are mounted on the

stanchions

17 and 18, the mat 16 of reinforcing rods placed over the joists and form boards and the concrete slab poured over the form boards and joist to complete a floor. When the concrete has set, the form-jacks 14 are removed in the manner illustrated in Figure 7 and the form boards 13 stripped from the underside of the concrete slab. To remove a form-jack the locking bar 21 is turned to the position illustrated in Figures 6 and 7 so that the

pins

53, 54 and 55 extend transversely of the spring strips 40 and 46 and the locking pin 56 aligns with the key hole slot 52. A downward force on the locking bar 21 against the spring strip 40 causes it to ex and

tilt stanchions

17 and 18 inwardly which, in turn, causes the spring strip 46 to ex and hinge the

struts

19 and 20 intermediate their ends. Such hinging of the

struts

19 and 20 shortens the length of the jack 14 so that the feet 28 slip over the bottom flanges 12 of the

joists

10 and 10 and the formjack falls to the floor below. The locking bar 21 is shown in Figure 7 being manually actuated, but in practice the locking bar would be pulled by an extension pole having suitable fingers for engaging the handle pin 57. The form boards 13 are then stripped from the concrete slab. A number of form-jacks 14 must be provided corresponding to the number required to support form boards 13 for ve different oors so that successive floors may be laid while the concrete of the lower floors is setting.

It will now be observed that the present invention provides a hinged form-jack of improved construction which facilitates the insertion and removal of the jack to and from the joists with which it is used. It also will be observed that the present invention provides a form-jack of the type indicated which is resiliently held in its normal extended position, but yields to hinge the jack intermediate its ends to adapt the jack to be inserted and removed. It will be further observed that the form-jack of the present invention may be easily and quickly adjusted to t joists of different heights and spacings. It will also be observed that the improved jack facilitates the locking and unlocking of the jack in position. It will still further be observed that the present invention provides a form-jack of the type indicated which is of simple, cornpact rugged and lightweight construction which may be economically manufactured and is reliable in operation.

While a single embodiment of the invention is herein illustrated and described it will be understood that modications may be made in the construction and arrangements of elements without departing from the spirit or scope of the invention. Therefore, without limitation in this respect, the invention is deiined by the following claims.

I claim:

1. A removable support for holding concrete form legs and each member having a hinge intermediate its ends; one of said members having its ends pivotally con-- nected to the legs, said members hinging to adapt the legs to be inserted between the anges of the spaced I- beam joists, a locking bar movable in aligned holes in the members and having shoulders engageable with the opposite sides of the members to lock the support in position between the beams, and means for releasing the engagement of a locking shoulder withone side of one member to permit the members to hinge when the support and lform boards are to be removed.

2. A removable support for concrete forms comprising spaced stanchions, spaced upper and lower struts extending transversely between said stanchions, the upper strut having separate sections with its outer ends pivotally con-l nected to the respective stanchions, the lower strut having separate sections with its outer ends rigidly connectedY to the respective stanchions, spring hinges connecting the inner ends of the sections of the upper and lower struts which normally hold the struts in spaced relation and yield to permit the struts to hinge, a locking bar extending through the spring hinges of the upper and lower struts and having shoulders overlying the opposite sides of the hinges to lock the struts in spaced relationship, and

a slot in the hinge of the lower strut for releasing the shoulder overlying the lower strut to` permit the struts to buckle relative to each other and collapse the support.

3. A support for concrete forms comprising a stanchion at each end, upper and lower struts extending `between the stanchion, each strut comprising separate rigid sections with adjacent ends of the sections connectedbyL aspring strip, the opposite ends of the upper strut being pivotally connected to the stanchions and the opposite ends of the lower strut being rigidly connected to the. stanchions, and a locking bar extending through the. spring strips and having lugs movable into locking and unlocking engagement with the sides of the spring stripsk whereby to adapt the support to be flexed for insertionv and removal and the struts locked to prevent flexing.

4. A removable support for concrete forms in accordance with claim 1 in which means are provided for adjusting the height of the stanchions to accommodate L,

beam joists of diterent heights, and means for adjusting the length of the spaced members relative to the legs to adjust the length of the support.

5. A support for concrete forms in accordance with claim 3 in which the stanchions are in the form of inverted U-shape yokes, the rigid sections of the struts are channels positioned between the sides of the stanchions, the ends of each section of the upper strut being pivotally connected to the stanchions by single pins extending through aligned holes in the sides of the stanchions and anges of the channels, and the ends of each section of the lower strut being rigidly connected to the stanchion by a plurality of pins extending through aligned holes in the sides of the stanchions and anges of the channels.

6. A support for concrete forms in accordance with claim 5 in which the flanges of the channels of each section have a plurality of spaced aligned holes whereby the length of the support may be adjusted in lixed increments by inserting the pins through different holes in the anges of the sections.

7. A support for concrete forms in accordance with claim 6 in which the inverted U-shape stanchions have foot plates attached to the lower ends which extend laterally from the stanchions.

8. A support for concrete forms in accordance with claim 6 in which inverted U-shape adapters are provided having spaced sides overlying the sides of the stanchions and a cross-piece overlying the top of the stanchion, said adapter plate being connected to the stanchion by spaced pins extending through the sides of the adapter and stanchions, and said adapter having a plurality of spaced aligned holes for cooperation with the aligned holes in the stanchion whereby the adapter may be attached to the stanchion at dilerent heights.

9. A support for concrete forms in accordance with claim 3 in which the locking bar is a rod extending through aligned holes in the spring strips of the struts, pins extending through the rod at opposite sides of the spring strips of the upper and lower struts, said hole in the Aspring strip of one of the struts being in the form of a key hole having a slot at one side through which a pin may pass to permit the spring strips to flex, and a handle for raising and turning the rod.

l0. A support for concrete forms in accordance withv References Cited in the le of this patent UNITED STATES PATENTS 2,557,693 Sachleben et al. June 19, 1951