FR2641303A1 - Metal formwork for the prefabrication of concrete elements of rectangular cross-section and elongate shape - Google Patents

Abstract

A formwork according to the invention comprises a horizontal base 5 which is placed on crosspieces 3 and on longitudinal members 4 which rest on shock-absorbing blocks 2. It comprises a box-shaped central partition 6 which is integral with the base and which contains vibrators 13. It comprises two lateral cheeks 7d, 7g which are supported by arms 10 which are articulated about a shaft 18 which is supported by a carriage 15 which moves in a transverse slide 16 having pairs of holes 14. The position of the carriage is controlled by means of a pin 17 which is engaged in one pair of holes 14. One application is the prefabrication of girders, posts and profiles made of reinforced or prestressed concrete.

Description

Metal forms for the prefabrication of concrete elements of
rectangular and elongated section.

DESCRIPTION
The present invention relates to metal forms for prefabricating concrete construction elements of rectangular section and of elongated shape, such as beams or posts.

 The technical sector of the invention is that of the construction of precast benches of concrete building elements.

 Prefabricated reinforced concrete or prestressed concrete beams or columns of rectangular section are widely used construction elements and there are many types of benches for prefabrication of these elements.

 The FR patent application. A. 2.152.515 (SARET) describes an installation for the prefabrication of concrete building elements which comprises a central wall and two side walls located on either side of the central wall, with which they delimit two molds, the together being placed on a sheet which constitutes the bottom of the molds. The side walls tilt around an axis which is carried by a slide which is mounted in a cross member secured to the floor, which tilt axis also serves to adjust the position of the slide. The side walls are blocked in a vertical position, by a part which comes to bear on an element integral with the floor.

 The installation described in this document allows two beams to be cast simultaneously, the width of which can be adjusted and the tilting of the side walls facilitates demolding.

The objective of the present invention is to provide improved metal forms intended to serve as molds for the prefabrication of reinforced concrete building elements of elongated shape and of rectangular section and in particular forms which make it possible to vary the width of the molds. in a wide range and which facilitate lateral movements of the side walls intended to vary the width of the molds
The forms according to the invention comprise, in known manner, a horizontal floor, a central vertical partition integral with said floor and two side walls which can tilt around a longitudinal axis and which are movable laterally.

The objectives of the invention are achieved by means of a formwork in which each of the side walls is carried by arms which extend outwards and which carry, at their lower part, two ears which are separated from said arms by a notch open inwards and each pair of ears carries a pair of holes, which holes are aligned longitudinally and receive an axis around which said side wall pivots
A formwork according to the invention comprises transverse horizontal rails which are each composed of two U-shaped profiles whose wings are arranged opposite one another, which rails are arranged below said horizontal floor, protrude beyond the sides lateral thereof and carry on their vertical webs pairs of holes which are aligned longitudinally and said formwork further comprises a small carriage comprising an elongated body which slides in said slide and which carries, at its external end, an axis hollow provided with two rollers which roll inside said sections, which hollow axis receives a pin which is engaged in a pair of holes in said slide and which serves to lock said carriage in a determined position to adjust the width of the molds and said elongated body carries, at its internal end, a hole which receives said axis which is engaged in a pair of holes carried by the ears of one of said arms.

 Advantageously, each carriage comprises a narrow body in the form of a square which is composed of a horizontal branch which slides inside a slide and a vertical branch which is connected to the external end of said horizontal branch carrying said hollow axis.

 According to a preferred embodiment, each support arm comprises two parallel flanges which carry, at their outer end, an axis on which is mounted a pivoting nut which receives a locking screw which bears on the upper end of the vertical branch of one of said carts.

 The invention results in new metal forms for the prefabrication of reinforced concrete or prestressed concrete construction elements of elongated shape and section having a generally rectangular shape.

 The formwork according to the invention has the advantage that the pivoting cheeks or side walls can be tilted without great effort because the axis of articulation is brought closer to the center of gravity.

 They also have the advantage that each side wall can be moved transversely by being mounted on small carriages which slide in horizontal slides, which makes it possible to easily move the side walls to vary the width of the beams. During the lateral displacement of a wall, it is easy to manually hold the latter in the slightly tilted position or in the equilibrium position, which avoids the friction of the lower edge of the wall against the floor and the wear of the joint d seal located along the bottom edge of the wall.

 Thanks to the method of linking the support arms of the walls with the carriage by ears which are separated from the arm by a notch open towards 1 t inside, through which the horizontal floor passes, it is possible to equip the formwork with a floor of large width and therefore to vary the width of the molds over a wide range and this result is achieved without having to move the pivot axis from the vertical of the center of gravity therefore without having to exert significant forces on the side cheeks for tip over.

 The lateral cheek locking system in vertical position by screws which are screwed into a swivel nut and which rest vertically on the body of the carriage does not hinder the tilting of the lateral cheeks and allows to crush the interposed seal between each side wall and the floor.

 The following description refers to the appended drawings which represent, without any limiting nature, an embodiment of a metal formwork according to the invention.

 Figure 1 is a vertical cross section of a formwork according to the invention in the maximum width position.

 Figure 2 is an exploded perspective view of part of a formwork according to the invention.

 Figure 3 is a cross section of a formwork according to the invention in the minimum width position.

 A formwork according to the invention is intended to serve as a prefabrication bench for reinforced concrete or prestressed concrete construction elements of elongated shape having a cross section of generally rectangular shape, for example a prefabricated bench for beams or columns.

 The formwork comprises cross members 3 which are placed on vibration damping blocks 2 which rest on the ground or on a solid block. Metal plates 1 can be inserted between the pads 2 and the ground.

The cross members 3 support parallel beams 4 which are constituted for example by two metal sections in the form of
U or Tee. The longitudinal members 4 support a horizontal floor 5 which consists of metal sheets placed on the longitudinal members.

The floor 5 serves as the mold base.

 The formwork comprises a central vertical partition 6 in the form of a hollow box made up of two parallel sheet metal walls 6a, 6b.

which are fixed on a metal frame. The box 6 is placed on the floor 5 and is fixed to the latter. The box 6 contains electrical resistors 11 intended to heat the molds to accelerate the setting of the concrete.

 I1 also contains vibrators 13, which are preferably unbalanced or eccentric vibrators driven in rotation by an electric motor. These vibrators vibrate the entire formwork and the concrete which is poured into the molds. A formwork according to the invention further comprises two side walls or cheeks 7d, 7g which can occupy a vertical position parallel to the central partition 6.

 We see in Figures 1 and 2 that each side wall has an inner sheet metal wall 22 which is stiffened by a frame 23 located on the outer side of the wall, that is to say on the side opposite to the central partition.

 Each internal wall 22 delimits with one of the lateral faces 6a or 6b of the central partition and with the floor 5 a mold 21d, 21g of elongated shape having a rectangular cross section.

 It can be seen in FIGS. 1 and 2 that the side walls have electrical resistors 11 there for heating the molds. It can also be seen in FIG. 1 that they are lined with a thermal insulating material 12.

 Figures 1 and 2 show side walls open at the rear. As a variant, they can obviously be closed by a sheet placed on the framework 23.

 The reference 8 represents seals which are interposed between the lower edge of each side wall and the floor 5.

 Each side wall is supported by a plurality of arms 10 which are fixed to the frame 23 and which extend outwards.

 We see in Figure 2 that each arm 10 is composed of two sheet metal flanges 10a, lOb identical and parallel, which are interconnected by a pin 24 on which is mounted a nut 9 in which a locking screw 19 can be screwed . The axis 24 and the nut can pivot relative to the two flanges, so that the screw 19 can tilt in the position shown in FIG. 1.

 It can be seen in FIG. 2 that the two flanges 10a and 10b carry two holes 25 which are aligned in the longitudinal direction and which are located near the internal end of two small flanges 26a, 26b in the shape of an ear which extend the main flanges 10a, lOb towards the arm and which are separated from these by a transverse notch 29 whose function will be explained later.

 The holes 25 of all the arms 10 carrying one of the side walls, are aligned and receive rods 18 which form an axis of articulation around which each side wall 7g or 7d can pivot.

 The addition to the two flanges 10a and 10b of two small flanges 26a, 26b carrying at their front end the holes 25 for passage of the articulation axes 18 makes it possible to bring each pivot axis closer to the center of gravity of the corresponding side wall, this which reduces the torque to be exerted on this side wall to tilt it, so that the side cheeks can be opened and closed manually, which allows for relatively inexpensive prefabrication benches. Of course, mechanical means can also be provided, for example hydraulic or pneumatic cylinders 30 mounted on cross members 31 to control the tilting of the side cheeks.

 The fact that the side cheeks can be brought into the open position manually makes it easy to keep them in this position while they are moved laterally, which prevents the cheeks from rubbing against the floor 5 and the wear of the seals 8 due to this friction.

 There is shown in Figure 2 a side cheek 7g in a position which corresponds to a mold 21g having a reduced width. In this position, the floor 5 projects laterally beyond the rear of the lateral cheek, and this projection is all the wider as one wishes to have the possibility of manufacturing beams having more different widths in the same mold.

 When a lateral cheek is in the position closest to the central partition, that is to say in the position where the mold which it delimits is the narrowest, the projecting part of the floor 5 penetrates into the notch. 29 which is open towards the inside, as can be seen in FIG. 2 and the presence of the two ears 26a, 26b separated from the arms lova, lOb by a notch 29 makes it possible both to place the tilting axis 25 in the vicinity of the center of gravity of a cheek therefore to tilt it manually and at the same time, allows to use a floor 5 of large width therefore to vary the width of the molds over a wide range.

 This arrangement allows the tilting axis 25 of the lateral cheeks to be placed under the floor 5 when the lateral position of the cheeks 7 is closest to the central partition, which was not possible with support arms such as those described in the application FR. 2,152,515.

 A formwork according to the invention further comprises slides 16 which are associated with each arm 10.

 Each slide 16 is composed of two parallel rails, for example two U-shaped sections 16a, 16b, the wings of which are placed facing each other and which are separated by a slot. The two sections delimit between them a raceway in which a carriage 15 moves. The two sections carry two rows of holes 14 which form pairs of holes aligned in the direction parallel to the longitudinal axis of the formwork.

 The slides 16 are located below the floor 5 and they extend laterally beyond said floor.

 Each slide receives a lateral positioning carriage 15 which has a central body in the form of a square sufficiently narrow to be able to circulate in the slot which separates the two sections 16a and 16b and to be housed between the two flanges 10a, 10b of an arm support 10.

 The central body comprises a horizontal branch 15a which circulates inside a slide 16 and a vertical branch 15b which is connected to the external end of the horizontal branch.

The horizontal branch 15a carries in the vicinity of its outer end two rollers 20 mounted on a hollow shaft 27 through which one can engage a pin 17 which also passes through a pair of holes 14 of the slide, so that the pin 17 allows fix the position of the carriage 15 in the slide.

 Figures 1 and the left part of Figure 2 show an embodiment in which each slide has four pairs of holes 14, which provides four possibilities for positioning the carriage 15, which determine four possible positions of the side cheek 7g placed in a vertical position, which are shown in dotted lines on the left part of FIG. 1. The right part of FIG. 1 represents an example in which each slide has six pairs of holes and where the side wall 7a can therefore occupy six positions different shown in dotted lines, which allows to manufacture with the same mold elements of different width. Of course, the number of pairs of holes 14 can be arbitrary.

 The horizontal branch 15a of each carriage 15 slides inside a slideway 16. It comprises, in the vicinity of its internal end, that is to say of its end directed towards the corresponding lateral cheek, a hole 28 which receives a pin end 18 whose length is slightly less than the internal width of the slide 16.

 The two ears 26a, 26b of an arm 10 are engaged on this end of the axle 18 which passes through the holes 25 carried by these ears, so that the arm 10 pivots around the end of the axle 18.

 Advantageously, the axis 18 carries two rollers 30 which roll inside the profiles 16a, 16b so that it is easy to move the carriages 15 carrying a side wall 7 laterally.

 To laterally move a side wall 7 in order to modify the width of a mold, the pins 17 are removed from all the carriages carrying the arms 10 supporting said wall and all the carriages and the wall are moved. During this operation, the axes 18 which are not removable, remain engaged in the holes 25 and the wall 7 is supported by a plurality of carriages which roll on their rollers.

 In addition, during this movement, the wall 7 can be manually pivoted around the axes 18 which have remained in place, which makes it possible to avoid the bottom edge of the wall and the.

seal 8 does not rub against the floor 5.

 This possibility does not exist in the case of a formwork like that described in the publication FR. 2.152.515 which does not carry trolleys rolling inside a slide and carrying the wall while it is moved laterally.

 There is shown in dotted lines on the left part of Figure 1 a side cheek 7g in the tilted position. During tilting, the horizontal branch 15a whose thickness is less than the width of the slot formed between the two sections 16a, 16b moves in this slot and does not hinder the tilting of the cheek.

 A formwork according to the invention comprises means for maintaining the lateral cheeks 7d, 7g in a vertical position to prevent them from pivoting when the concrete is poured into the molds. We have already seen that the parry of flanges lova, lOb making up each support arm 10 carried, at their external end a pin 24 carrying a nut which can pivot with the pin and into which a screw 19 is screwed.

 We see on the right part of Figure 1 and in Figure 2 that, when a side cheek is in the vertical position, we place the screws 19 in the vertical position and we screw them so that they come to bear on the upper ends vertical branches 15b of the carriages 15. The tightening of the screws gives rise to a torque around the axes 25 which opposes the tilting of the cheeks outwards.

 In addition, the tightening of the screws 19 makes it possible to slightly crush the joints 8 against the horizontal floor 5 and thus to obtain a good seal of the junction between the side cheeks and the floor.

 We see on the left side of Figure 1 that when a side cheek is in the tilted outward position, the nut 9 and the screw 19 can pivot around the axis 24, which prevents the screw from coming abut the carriage 15.

 The vertical branch 15b of the carriage then engages between the two flanges lova, lOb and the side cheek can therefore pivot freely, which makes it possible to obtain a large opening of the molds for the positioning of the frames therein.

 Of course. the height of the beams can be varied either by adding extensions to each side cheek which increase their height, or by replacing the side cheeks with higher cheeks.

 FIG. 1 shows an example in which the two lateral cheeks 7g, 7d have different heights and also different lateral displacement possibilities, which makes it possible to manufacture a range of construction elements having different heights and widths.

 The right part of FIG. 1 represents slides having six holes 14, which gives six widths of different positions. In this case, the floor 5 is wider on the left side and the notch 29 is also deeper.

 3 shows a vertical section similar to Figure 1 passing through side rails on which the two side walls 7d, 7g are shown in their vertical position corresponding to the molds of smaller width. This figure shows the lateral overflows of the floor 5 beyond the side walls intended to allow the lateral displacements of the latter to widen the molds. It can also be seen that the slides 16 extend under the floor 5 and that the axes 18 of articulation of the cheeks occupy positrons located under the floor when the side walls are in their extreme positions towards the inside.

 FIG. 3 shows the center of gravity G of each pivoting wall and it can be seen that the pivot axis 18 is placed in the vicinity of the vertical of the center of gravity.

 We also see that the notches 29 open inwards, allow the passage of the overflowing parts of the floor 5 and the depth of these notches is proportional to the width of the overflow, that is to say the number of holes 14 that comprise the slides 16 since the overflow of the floor 5 corresponds to the distance between the end holes 14 carried by the slides 16.

 The right part of Figures 1 and 3 show slides 16 having six holes 14 while the left parts of these figures show slides having four holes 14 and we see that the notch 29 of the right part is deeper than the notch 29 on the left. Consequently, the support arms 10 of the right part are also longer than the arms 10 of the left part.

 When the side walls 7g, 7d are in the extreme internal position shown in FIG. 3, they must be able to pivot freely relative to the axis 18 which is located under the horizontal floor. To this effect, the internal end of the ears 26a, 26b which pivot around the axis 18 have a semicircle shape centered on the axis 18, the diameter of which is equal to or less than the diameter of the rollers 30, and therefore at the height of the slides 16, so that when the side wall pivots, the internal ends of the ears 26a, 26b can pivot freely without abutting against the floor 5.

 FIG. 2 shows lateral arms 10, the two flanges 10a, 10b of which carry two holes 32 aligned in the longitudinal direction in which a pin 33 can be engaged which also passes through a hole 34 carried by the vertical branch 15b of the carriage 15 which makes it possible to block the side cheeks in the open or tilted outward position during the movements of these cheeks or during the positioning of the frames in the molds.

Claims (8)

 1. Metal formwork for the prefabrication of concrete elements of rectangular section and of elongated shape of the type comprising a horizontal floor (5), a central vertical partition (6) and two side walls (7g, 7d) which are articulated around 'a longitudinal axis (18) and which are laterally movable, characterized in that each of said side walls (7g, 7gd) is carried by arms (10) which extend outwards and which carry at their lower part two ears (26a, 26b) which are separated from said arms by a notch (29) open inwards and each pair of ears (26a, 26b) carries a pair of holes (25), which holes are aligned longitudinally and receive a axis (18) about which said side wall pivots.  2. Formwork according to claim 1, characterized in that it comprises transverse horizontal slides (16) which are each composed of two U-shaped profiles (16a, 16b) whose wings are arranged opposite one another, which slides are arranged below said horizontal floor (5), protrude beyond the lateral sides of the latter and carry on their vertical sides pairs of holes (14) which are aligned longitudinally and said formwork further comprises, a small carriage (15) comprising an elongated body (15a) which slides in said slide and which carries, at its external end, a hollow axle (20) provided with two rollers (27) which roll inside said profiles (16a , 16b), which hollow axis receives a pin (17) which is engaged in a pair of holes (14) of said slide (16) and which serves to lock said carriage (15) in a determined position to adjust the width of the molds and said hello body ngé carries, at its internal end, a hole (28) which receives said axis (18) which is engaged in a pair of holes (25) carried by the ears (26a, 26b) of one of said arms (10).  3. Formwork according to claim 2, characterized in that each of said axes (18) carries a pair of rollers (30) which roll inside said sections (16a, 16b) forming a slide.  4. Formwork according to any one of claims 2 and 3, characterized in that each carriage comprises a narrow body in the form of a square which is composed of a horizontal branch (15a) which slides inside a slide and a vertical branch (15b) which is attached to the outer end of said horizontal branch (15a) carrying said hollow axis (27).  5. Formwork according to claim 4, characterized in that each support arm (10) comprises two parallel flanges (lova, lOb) which carry, at their outer end, an axis (24) on which is mounted a pivoting nut (9) which receives a locking screw (19) which bears on the upper end of the vertical branch. (15b) of one of said carriages (15).  6. Formwork according to claim 5, characterized in that said side walls comprise a seal (8) which is interposed between their lower edge and said horizontal floor (5) and which is crushed by the tightening of said locking screws ( 19) z.  7. Formwork according to any one of claims 1 to 6, characterized in that said central partition (6) has the form of a hollow box which contains vibrators (13) which vibrate the entire formwork which is mounted on shock absorbing pads (2).  8. Formwork according to any one of claims 1 to 7, characterized in that said central partition (6) and said side walls (7g, 7d) contain electrical resistors (11) for heating the molds.