US2866252A

US2866252A - Concrete form holders

Info

Publication number: US2866252A
Application number: US733552A
Authority: US
Inventors: Walter H Cobi
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-05-07
Filing date: 1958-05-07
Publication date: 1958-12-30
Anticipated expiration: 1975-12-30

Description

Dec. 30, 1958 w. H. coal CONCRETE FORM HOLDERS 2 Sheets-Sheet l Filed May 7, 1958 nvm Dec. 30, 1958 w. H. coal CONCRETE FORM HOLDERS 2 Sheets-Sheet 2 Filed May 7. 1958 United States Patent Oice 2,866,252 Patented Dec. 30, 1958 CONCRETE FORM HOLDERS Walter H. Cobi, Port Chester, N. Y.

Application May 7, 1958, Serial No. 733,552

9 Claims. (Cl. 25-131.5)

This invention relates to form holders for concrete oor or slab construction and more particularly to a form holder of the collapsible type used primarily for facilitating the installation and removal of concrete forms which are employed in pouring concrete iloors or slabs supported on cross supports or joists.

This application is a continuation-impart of my copending application Serial No. 658,173 for Concrete Form Holders filed May 9, 1957 (now abandoned).

In the construction and erection of buildings it is now common practice to make the oors of reinforced concrete. One method, now extensively employed, is to mount structural steel floor joists of I cross-section on suitable main structural members. These joists may be of the solid web I-beam type or of the open web type and are herein called I-beam joists. The joists are arranged in spaced-apart, parallel relation to support the concrete floor. Although there is no fixed rule as to spacing of the joists, they may conveniently be spaced so that a two feet wide, live-eighths inch thick plywood form can t between adjacent pairs of joists, and be suitably mounted there to provide the form to support poured concrete until the concrete has set. After the desired number of forms are mounted in place between the upper flanges of the I-beam joists, it is customary to place wire mesh reinforcement over the surface, by rolling out the wire mesh from rolls over the forms. This woven wire or mesh wire is to provide reinforcement for the concrete which is poured to form the slab. After the concrete has sufficiently set or hardened the plywood forms are removed or stripped oil, leaving the reinforced set concrete slab which is to form the floor.

One system. utilizing this general method of construction, employs metal clips for supporting the plywood forms between the jcists, These metallic clips are of a metal strong enough to support the form during the pouring and setting of the concrete but which is sufiiciently brittle that the clip may be broken by a hammer blow. These clips are suspended on the joists prior to placing the plywood forms between the joists. The plywood pieces are then laid in place and suported on the metal clips to provide the concrete form. Wire mesh is then rolled out over the surface provided by the joists and forms, and then concrete is poured and allowed to set. After the concrete has suiliciently hardened, the clips, supporting the plywood forms, are broken off by an impact blow against them and the plywood stripped off, leaving the reinforced concrete slab. Clips used in this system and the general method employed are described in U. S. Patent No. 2,731,701. Although the system utilizing these metallic clips has been extensively used, it will be manifest that the clips may be used only once, because they must be destroyed when they are used for their intended purpose. Because of the fact that the clips cannot be reused and serve no useful purpose after the forms are removed, this system represents a considerable expense, which, if possible, should be reduced.

My invention provides a form holder for a concrete form of the kind mentioned above, but which do-es not require the use of clips which are destroyed in a single use. According to my invention a form holder is provided which is readily mounted on the floor joists prior to laying down the concrete form (usually pieces of plywood) and which provides support for the form during the subsequent operations of pouring the concrete and permitting it to set to form the reinforced concrete slab. And, after the concrete has set the form holder provided by my invention may be quickly and easily removed to permit removal or stripping of the form. But, in addition, my novel form holder may be used over and over again. Accordingly, the invention not only provides a form holder which is easily and effectively installed and used for its intended purpose of supporting the concrete form but it has the further and economical advantage of being capable of repeated reuse.

According to a preferred embodiment of my invention, the form holder comprises a pair of legs, comprising a left and a right leg, which are hingedly connected at their inner ends, and the legs at their outer ends are provided with foot portions, which are adapted to rest upon the lower flanges of adjacent parallel, spaced apart, I-beam joists; the hinged connection of the two legs being located substanially midway between the feet of the right and left leg. Each leg is provided with a form supporting aim, which may, if desired, be mounted in a way to bevcrtically adjustable. A movable locking device is provided which is adapted to be moved into locked position to lock the legs in a predetermined position with their feet resting upon the lower inside flanges of a pair of adjacent I-beam jcists and to unlocked position to permit the legs to be moved to release the feet from the flanges of the l-beams, so that the form holder may be folded or collapsed and easily and readily removed for re-use. After removal of the form holder the form can then be stripped from the set concrete. ln effect, the form holder according to certain embodiments of my invention provides a collapsible three hinged arch, which may be set between two adjacent parallel l-bcams to form an arch to support an overlying concrete form (such as plywood), which arch may be collapsed at any time to permit the overlying form to be stripped from the set concrete, even though the form may then be somewhat weighted down by the overlying concrete slab. Or, the form holder may be modified to serve as a beam, as distin guished from a three hinged arch. The beam form also may be readily collapsed to permit the stripping of the form from the set concrete. lf desired, the fcet portions at the ends of the legs may be provided by vertically or laterally adjustable members.

Although the novel features which are believed to be characteristic of the invention are pointed out in the annexed claims, the invention itself as to its objects and advantages and the manner in which it may be carried out may be better understood by reference to the following more detailed description taken in connection with the accompanying drawings, forming a part hereof, in which Fig. l is a sidc view in elevation of a concrete form holder embodying my invention, the holder being shown in locked position between a pair of adjacent l-beam joists, with an overlying plywood form supported thereon, and an overlying poured concrete licor slab; the dotted lines showing in phantom the position of the holder in partially collapsed condition;

Fig. 2 is a view on line 2 2 of Fig. l;

Fig. 3 is a view in section to show the mounting of the locking pin holders and locking pin;

Fig. 4 is a view in perspective of the concrete form holder, shown in Fig. l; and

Fig. 5 is a view in perspective, partly broken away, of a modification showing vertically adjustable feet;

Fig. 6 is a view in perspective of a further modificanon;

Fig. 7 is a view on line 7-7 of Fig. 6; and

Fig. 8 is a view on line 8-8 of Fig. 6.

Referring now to the drawings, in which like reference characters denote similar parts throughout the several views, there is illustrated in Fig. l a pair of I-beam joists, to represent a pair of

adjacent joists

10 and 11 in a floor construction of the kind mentioned above. The form holder H is shown in locked position in Fig. 1 with an overlying concrete form F resting thereon. This form, as shown, is a piece of live-eighths inch thick plywood which may be of any desired length, say four to eight feet, and its width corresponds to the distance between the

upper flanges

14 and 15 of the joists. Ordinarily the joists will be mounted on about two feet centers although they may be a greater or less distance apart. The plywood form piece 16 is so placed that the concrete slab 17 after the concrete is poured and has set and the form removed will provide lateral bracing for the

edges

12 and 13 of the anges of the I-beam joists. The holder H is locked in position between I-

beam joists

10 and 11, as shown in Fig. 1. And it will be understood that a sufficient number of holders H are used along the length of the form to support the overlying form and finally to support the concrete Cz which is poured over the area of the form. It will be understood that a sufficient number of form boards I6 will be laid in and supported on holders H to cover the entire oor area on which the concrete is to be poured to form the floor slab 17. Prior to pouring concrete, it is customary to place wire reinforcements over the hoor area to make a reinforced concrete slab. After the concrete has set, the holders H are collapsed, as described in further detail hereinafter, and removed from beneath the form F and the plywood form boards 16 are then stripped from the hardened concrete, leaving the bare, reinforced concrete slab 17 supported on the I-

beam joists

10 and 11 throughout the area of the oor.

The collapsible concrete form holder H, itself, comprises a pair of

leg members

20, 21. The leg member 20, for convenience referred to as the left leg, is made up of two

plates

22, 23 disposed in parallel vertical planes. The outer ends of the

plates

22, 23 are bent at right angles to form

end flanges

24, 25 and cross plate 26 is secured to these flanges as by welding. The cross plate 26 preferably is bent at right angles at its bottom to form a flange 27. Although this flange is not necessary, it forms a desirable foot portion. In the absence of the flange 27, the bottom edges of the cross piece 26 and

flanges

24, 25, serve as a suitable foot portion at the outer end of leg member 20.

The

plates

22, 23 of leg member 20 are maintained in spaced parallel relation by spacing and reinforcing

rods

28, 29 and a cross bar 19 welded to the inner ends of

plates

22, 23. The rod 29 is in the form of a bolt, threaded at each end to accommodate

nuts

30, 31. Mounted on the inner surfaces of

plates

22, 23 are a pair of

channels

32, 33, forming a pair of vertical guideways, in which is mounted a form supporting arm 34, having downwardly extending

legs

35, 36 and a shoulder cross piece 37, which is adapted to engage the concrete form F and acts as a shoulder upon which the form rests when the holder H is locked between the

joists

10 and 11. The

legs

35, 36 are provided with a number of vertically spaced pairs of registering holes, 38, 39, 40. The

plates

22 and 23 are provided with a pair of registering holes 4l. A bolt 44, threaded at both ends to accommodate

nuts

42, 43, extends through the registering holes, and thus clamps the form support arm 34 in a given vertical position, depending on which of the

pairs

38, 39 or 40,

4 of holes in the

legs

35, 36 is registered with the plate holes 41. It may be desirable in some instances to make the cross piece 37 in the form of a roller and mount it between the legs 3S, 36 so that it may rotate on its axis. In this construction the form would rest upon the roller instead of upon the at cross piece 37.

The

plates

22, 23, are provided with a pair of oppositely disposed registering elongate horizontal slots 48 closed at their ends and also a pair of oppositely disposed

vertical slots

50, 51 open at their upper ends. A pair of reinforcing

plates

52, 53, having corresponding vertical slots are welded to the inside of the

plates

22, 23, it being understood that the

holder leg members

20, 21 are made of relatively thin gauge metal plate, which may be of steel or other suitable metal. Aluminum alloy may be used where a particularly lightweight holder is desired.

lThe right leg member 21 is constructed in substantially the same way as left leg member 20 and it is deemed unnecessary to describe it in detail. The corresponding parts are designated by reference numerals having a sub a." For example, plate 22a corresponds to plate 22 and likewise throughout the figures. However, it should be noted that

plates

22a, 23a are not spaced apart the same distance as

plates

22, 23.

Plates

22a, 23a are spaced apart so that their exterior surfaces at their inner ends will fit and telescope into the inner surfaces of

plates

22, 23 at their inner ends, as shown in the drawings.

The left and

right leg members

20, 21 are hingedly connected together at their inner ends. A hinge bolt or pin 56 passes through the four registering horizontal elongate

closed end slots

48, 48a in the

plates

22, 22a, 23, 23a to provide a pivoted joint, joining the left and

right leg members

20, 21. This bolt is threaded on both ends and accommodates a nut 57 outside of plate 22 and a nut 58 on the outside of plate 23. The left and right leg members may be collapsed about this pivot bolt 56 when the locking means (later to be described) is in unlocked position.

The locking means, as shown, comprises a locking bolt 60, rotatably mounted crosswise on a pair of

links

61, 62 at their outer ends, nuts 54, 5S, holding the bolt in place in the links. The inner ends of

links

61, 62 are pivotally mounted on a cross bolt 63, which extends through

plates

22, 23; the links being held on the bolt by means of

nuts

64, 65. lt will be seen that the locking bolt may be swung upwardly or downwardly on the

links

61, 62, which can be swung around bolt 63 as a pivot. Yieldable means are provided which normally urge the bolt 60 and

links

60, 61 to swing downwardly clockwise about pivot 63, as viewed in Fig. 1. This yieldable means, as shown, comprises a pair of

springs

66, 67 of spring steel wire mounted on the outer ends of spacer bolt 29 and held in place by

nuts

30, 31. lt will be noted that the

springs

66, 67, bear on the links 6l, 62, urging them in a clockwise direction about their pivot 63.

It will be seen from the foregoing that the locking bolt 60 will enter into the -

vertical slots

50, 50a, 51, 51a when these slots are brought into registry, as shown in the drawings. When the

feet portions

27 and 27a are placed on the inner

lower flanges

70, 71 of I-beam joists 10 and 11 (see Fig. l), and the vertical slots brought into registry, the locking bolt 60 is urged downwardly into the slots by

springs

66, 67 and in this position the left and

right leg members

20, 21 become locked into position between the l-

beam josts

10 and 11, with the

feet

27, 27a resting on the inner

lower flanges

70, 71 of thc I-beam joists. When the locking bolt 60 is lifted out of the vertical slots, the leg members are unlocked and the leg members may be collapsed about the pivot hinge bolt 56 as shown in dotted lines in Fig. l. The

elongate slots

48, 48a will permit the

feet portions

27, 27a to bc brought toward each other suiciently to release thtl holder H from between the I-beam joists so that it can be removed. The concrete form holder may be used as follows: The holder H with the legs collapsed about pivot 56 may be placed betwt en a pair of adjacent I-beam joists such as joists 1l), 1l. The

feet

27, 27a are placed on the lower

inner flanges

70, 71 and the vertical slots S0, 50a, 51, 51a brought into registry, so that the locking bolt 60 will move into the slots; the bolt 6I] being urged into the slots by the yieldable springs 66, 67. In this position the holder H is locked in position between the I-beam joists 1t), 11. A suitable number of such holders are placed and locked along the length of the joists and then the plywood piece 16, constituting a concrete form, is laid between the upper flanges of the

joists

10, 11 on to the form holders. The vertically adinstable form-supporting

arms

34, 34a are adjusted by means of the

holes

38, 39, or 40, to register with bolt 44 to bring their height to a position in which the form board 16 lies between the upper flanges of the l-

beam joists

10, 11. Furthermore, it should be noted that the tolerance may be such as to expose, at most, a very small crack between the board form 16 and the flanges, with the result that there is little leaking of concrete when it is poured over the form.

After a suthcient number of plywood boards, like 16, are placed over the entire area over which a concrete slab is to be poured to form the floor, reinforcement wire mesh may be placed over the area and then the necessary amount of mixed wet concrete is poured on to the concrete form provided by the boards 16 and upper surfaces of the upper flanges of the I-beam joists. The locked-in holders H will support the form boards 16 and the Weight of overlying concrete.

After the concrete has set and has become sufficiently hardened, the holders H are unlocked and removed from under the form boards and from between the 1- beam joists, and the boards 16 may then be stripped for re use in another place. If desired, a suitable tool 74 may be provided to facilitate the unlocking of the legs of the holder H for its removal from between the I- beam joists. This tool comprises a head end 75, having a face 76, and a long handle 77. The head has a bracket 78 secured to the handle 77. The tool is placed as shown in dotted lines in Fig. l, with the bracket 78 under pivot pin 56 and the face 76 under the locking pin 60. The handle 77 is moved toward pin 60 and the face 76 engages it and raises it out of the

vertical slots

50, 50a, 51, 51a to unlock the

legs

20, 21. The legs may then be collapsed about pivot pin 56 and the holder released from the I-beam joists. The pivot pin 56 will be caught on bracket 78 and the holder H may then be lowered with the tool.

It will be seen from the foregoing that the holder H is in effect a 3 hinged arch, comprising hinges A, B, and C. When the weight of the form F and overlying concrete bears upon supporting

arms

34, 34a which is inside of but near the outer ends of the leg members 20. 21, the legs exert a force against the locking pin at C and the feet exert a force at A, B against the ilanges 7i), 71 to maintain the holder in its proper position between the I-beam joists.

A modified form of holder is illustrated in Fig. 5. ln this modicatiou the feet at the outer ends of the legs are vertically adjustable so that the holder will accommodate itself to I-beam joists of different heights. For example, the I-beam joist 80 sho-wn in Fig. 5 is of the open web type which comprises

lower flanges

81, 82,

upper tlanges

83, 84 and an open web member 85. The holder Ha shown in Fig. 5 is constructed substantially like that as described in connection with holder H shown Vin Figs. l-4, except that a vertically adjustable foot member 86 is provided at each end of the holder. This plate 86 is turned outwardly at its bottom to provide a foot 87 to rest upon the lower ange of the joist and the plate is mounted to slide in a guideway provided by

angle irons

88 and 89 welded to

side plates

22 and 23.

A series of holes 90 is provided in the end plate 26 and corresponding holes are provided in plate 86. Bolts 91 may be inserted through th.A registering holes to maintain the plate 86 in any desired vertically adjusted pnsition. It will be understood that a similar arrangement is provided at each end of holder Ha. Hence, the foot members 87 at each end of the holder Ha may be adjusted to accommodate the holder to any height of tlanged joist in order to support the form board 16 in its proper place for pouring concrete.

'the en' cdirnent shown in Figs. 6, 7 and S is simpler in construction than those embodiments described above: is less costly to manufacture; and has been found in every way to be satisfactory in actual commercial use. The form holder HH (Figs. 6, '7, 8) comprises a pair of legs 12.1), 121. The leg member 120, for convenience referred to as the left leg, is preferably made of one-piece heavy gauge galvanized sheet metal by bending it to form an end portion 126 and two oppositely disposed plate members 122, 123 at right angles to end plate 126 and disposed in parallel vertical planes. The ends of plates 122, 123 where they join the cross piece 126 are herein designated the outer ends.

The plate members 122, 123 of leg member 12) are maintained in spaced parallel relation by spacing and reinforcing strips 129, welded at their ends to the leg plates 122, 123. Removably mounted on the leg plates` 122, 123, near their outer ends is a form supporting arm 134, having downwardly extending legs 135, 136 and a shoulder cross piece 137. Welded to the downwardly extending legs 135, 136 are clips 132. 133 which rest on the edges of plates 122, 123 in rectangular cutouts 140, 141 provided for this purpose. Registering holes 138 in the supports 134 and in the legs 122, 123, accommodate a pin which may be used to maintain the parts from becoming separated when the holder is being handled. Holes in end piece 126 may `bc used to attach a separate foot or lateral extension to the leg 120 of the form holder.

The plate members 122, 123 are provided with a pair of oppositely disposed registering pivot pin holes 148 and also a pair of oppositely disposed registering vertical slots 150, 151, open at their upper ends.

The right leg 121 is constructed in substantially the same way as lett leg 120 and it is deemed unnecessary to describe it in detail. The corresponding parts are designated by the same reference numerals but bearing a sub "an" For example, plate 12211 corresponds to plate 122 und likewise throughout Figs. 6, 7 and 8. However, it should be noted that plates 1220, 123g are not spaced apart the same distance as plates 122, 123 but are spaced apart so that their exterior surfaces at their inner ends will tit land telescope into the inner surfaces of plates 122, 123 at their inner ends, as shown in the drawings.

Leg plates 1220, 1.23n, like plates 122, 123 are provided with a pair of oppositely disposed registering pivot pin apertures 14551, which register with apertures 148 in plates 122. 123. Plates 122g and 123e are also provided with a pair of oppositely disposed, registering slots 150G, 151n open at their upper ends. These slots 150a. 151n register with slots 150, 151.

A hinge pivot pin 156 extends through the registering pivot pin holes 148, 148:1 and is maintained in place by head 157 anda screw nut 15761.

A locking bolt 160 is mounted crosswise at the inner ends of a pair of links 161, 162 and suitably secured to the links, as by a drive pin. The links in turn are pivotally secured at their outer ends to the leg plates 1122 and 123 respectively by pivot rivets 16-1, the pivot rivet for the outer end of link 162 not being .shown in the drawing. However. it registers with pivot 16'., so that the pair of said oppositely disposed pivots 164 have a common ais about which the links 161, 162, and consequently lock bolt 160, may be swung, as described in connection with the lock bolt 6d and links 6l, 62 shown in the embodiment disclosed in Fig. 4. That is, the locking bolt 160 may be swung downwardly to rest in the four registering slots 150, l50a, 151, 151er in the upper edges of the leg plates, to lock the legs in the position shown in Fig. 6. And the locking bolt 160 may be moved upwardly out of the slots by swinging the links upwardly about pivot axis 164, to unlock the legs 120, 121. In unlocked position the legs 120, 121 may swing about pivot pin 156, to collapse the form holder.

Plates 122, 123 are provided at their inner ends with a reinforcing and spacing strip 152 welded to the plates and extending across the lower edges of the inner ends of the plates. This strip 152 provides a stop or rest member which is engaged by the lower edges of plate members 122:1, 123er, when the holder is in locked position.

Thus it is seen from the foregoing description that the embodiment shown in Figs. 6, 7, and 8, operates in all material respects like the embodiment disclosed in Fig. 4', although it may be said that in locked position it acts more like a beam than as a three hinged arch.

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Also it is intended that the phrase I-beam joists as used herein and in the claims shall mean l-beam joists of the open web type and also the solid web type.

What is claimed is:

l. A collapsible holder adapted to rest on a pair of parallel spaced apart l-beam joists having lower flanges for supporting a concrete form which comprises a pair f hinged leg members comprising a left and a right leg each having an inner and outer end, each of said legs at its outer end having a foot portion adapted to rest upon the lower ange of one of said pair of adjacent spaced apart l-beam joists, a connection at the inner ends of said legs providing a pivot joining said leg members together, registering open end slots in each of said leg members near their inner ends, a locking member mounted on one of said legs movable to a position within said registering slots in which said legs are locked and maintained in a fixed position for supporting an overlying concrete form with sait'. feet portions resting on said flanges, said locking member being movable out of said registering slots to a position in which said legs are unlocked, said legs when in unlocked position being movable about said pivot to collapse said holder to permit removal of said holder from beneath said overlying concrete form.

2. A. device constructed according to claim 1 in which said foot portions are vertically adjustable.

3. A collapsible holder adapted to rest on a pair of parallel spaced apart l-beam joists having lower lianges for supporting a concrete form which comprises a pair of hinged leg members comprising a left and a right leg cach having an inner and outer end, each of said legs at lts outer end having a foot portion adapted to rest upon the lower flange of one of said pair of adjacent spaced apart l-beam joists, a connection at the inner ends of said legs providing a pivot joining said leg members together, registering vertically disposed slots in said leg members open at their upper ends, a locking bolt mounted on one of said legs for swingable movement to a position within said open end registering slots in which position said legs are locked by said bolt and maintained in a fixed position for supporting an overlying concrete form with said feet portions resting on said anges, said bolt being movable to a position out of said slots in which said legs are unlocked, said legs when in unlocked position being movable about said pivot connection to collapse said holder to permit removal of said holder from beneath 8 said overlying concrete form, a vertically adjustable form support member mounted on and near the outer end of each of said legs serving as supports on which an overlying form may be laid and supported when said feet portions are resting on said lower anges and said legs are in locked position.

4. A device constructed according to claim 3 in which each of said foot portions is attached to a plate mounted at the end of each of said legs for movement to different vertical positions.

S. A collapsible holder adapted to rest upon a pair of spaced apart I-beam joists having lower flanges for supporting a concrete form which comprises a pair of hinged leg members comprising a left and a right leg, each of which comprises a pair of spaced apart plates, each pair of plates having an inner and an outer end and having a foot portion at its outer end adapted to rest upon the lower flange of one of a pair of adjacent spaced apart I-beam joists, rregistering closed end slots in each of said plates at their inner ends, a pivot pin through said slots providing a pivot joining said leg members together, locking means comprising a locking bolt mounted on links pivoted to the plates of one of said legs, registering vertical slots open at one end thereof in each of said plates and positioned near their inner ends, into which said locking bolt is moved to lock said legs in a xed position for suporting an overlying concrete form with said feet portions resting on said anges, said locking bolt being movable out of said vertical slots to a position in which said legs are unlocked, said legs when in unlocked position being movable to collapse said holder and permit its removal from beneath said overlying concrete form.

6. A device according to claim 5, having a vertically adjustable form-supporting member mounted near the end of each of said leg members and a vertically adjustable foot member mounted at the end of each of said legs.

7. A collapsible holder for supporting an overlying concrete form of plywood between the upper flanges of an adjacent pair of lbeam joists having upper and lower flanges, which comprises a pair o hinged leg members comprising a left and a right leg, each leg comprising a pair of flat plates spaced in vertical parallel planes and having an inner and outer end, a cross plate secured at right angles to the said pair of left leg plates at their outer ends and providing a left foot portion, a cross plate secured at right angles to said right leg plates at their outer ends and providing a right foot portion, said feet portions being adapted to rest upon the lower anges of said pair of adjacent l-beam joists, registered slots closed at their ends in each of said four plates near their inner ends, a pivot pin extending through said slots and providing a. pivot conection pivotally joining said right and left leg members, a vertical slot open at its upper end in each of said four leg plates, means on one of said leg members mounting a locking pin for vertical movement into and out of said vertical slots, said vertical slots lying in registry when said feet portions are resting upon said pair of lower flanges, said locking pin locking said leg members in formsupporting position between said joists when said locking pin is moved into engagement with and into said four registered vertical slots and said legs being collapsible about said pivot when said locking pin is disengaged and removed from said vertical slots, said form holder in collapsed condition being removable from between said jcists to permit stripping of said form after concrete is poured and set thereon.

8. A collapsible holder for supporting an overlying concrete form of plywood between the upper anges of an adjacent pair of l-beam joists having upper land lower flanges which comprises a pair of hinged leg members comprising a left and a right leg each leg comprising a pair of ilat plates spaced in vertical parallel planes and having outer and inner ends, a cross plate secured at right angles to the said pair of left leg plates at their outer ends iand providing a left foot portion, a cross plate secured at right angles to said right leg plates at their outer ends and providing a right foot portiin, said feet portions being adapted to rest upon the lower flanges of said pair of adjacent I-beam joists, registered slots closed at their ends in each of said four plates near their inner ends, a pivot pin extending through said slots and providing a pivot connection pivotally joining said right and left leg members, a vertical slot open at its upper end in each of said four leg plates, a pair of locking bolt holders pivotally mounted on one of said leg members, a locking bolt mounted on said locking bolt holders and movable into and out of said vertical slots, said vertical slots lying in registry when said feet portions are resting upon said pair of lower flanges, yieldable spring means normally urging said locking bolt into said vertical slots, said locking bolt locking said leg members in form-supporting position when said locking bolt is moved into engagement with and into said four registered vertical slots and said legs being collapsible about said pivot when said locking bolt is disengaged from and removed from said vertical slots, said form holder in collapsed condition being removable from between said joists to permit stripping of said form after concrete is poured and set thereon.

9. A collapsible holder adapted to rest on a pair of parallel I-beam joists having lower llanges for supporting a concrete form and to be collapsed and removed for stripping the form after concrete poured on said form has set, which comprises a pair of hinged leg members comprising a left and a right leg, each of which comprises at least one vertically disposed plate member having an inner and an outer end and each leg member having a foot portion at its ouisr end adapted to rest upon the lower ange of one of a pair of adjacent spaced apart I-beam joists, registering pivot apertures in each of said plate members positioned near their inner ends, a pivot pin through said registering apertures providing a pivot, hingedly joining said leg members together, locking means comprising a locking bolt mounted on links pivoted to one of said legs, registering vertical slots open at their upper ends in each of said plate members into which said locking bolt is moved to lock said legs in a tixed position for supporting an overlying concrete form with said feet portions resting on said anges, said locking bolt being movable out of said vertical registering ylots to a position in which said legs are unlocked, said legs when in unlocked position being movable to collapse said holder by moving said hinged legs about said pivot pin to permit the removal of said holder from beneath said overlying concrete form.

References Cited in the iile of this patent UNITED STATES PATENTS 642,972 Frolich Feb. 6, 1900 644,986 Lechner Mar. 6, 1900 737,133 OBrien Aug. 25, 1903 FOREIGN PATENTS 27,590 Great Britain Dec. 4, 1906 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,866,252 December 30, 1958 Walter H. Cobi It is hereby certied that error a.

patent requiring tion and that the said Letters Patent should read as corrected below. In the drawin ppears in the above numbered (SOITEC gs, Sheet 3, containing Figures 6, 7, and 8, as shown below, should be inserted as part of the Letters Patent Dec. 30, 1958 w. H. coal ucnm vom Hamm 5 Sheath-8h. 8

nm In 1,1m

read -8 Shoalsts-Shset 2.-,

in the the drawings, Sheet 1, line 3, for 2 Sheet 1 S t 2, line 3, for 2 Sheets-Sheet 2 Signed and Sealed this 28th day of April 1959.

[SEAL] Attest T. B. MORROW,

Commissioner of Patents.