Laying with spacers for concrete works and spacers cartridge

DESCRIPTION

Forming the object of the present finding is a laying process of spacers for cement structures and the related spacer-carrying cartridge.

The spacers referred to are elements made of plastic material with circular, polylobed, square, rectangular or similar form. They are fit by slight interference on the reinforcement bars of the cement according to pre-established length intervals, so to determine the size of the bar cover by virtue of their radial dimension. In other words, such spacers serve to determine the thicknesses of reinforced cement between reinforcement and formwork in order to ensure a controlled covering of the steel. Example of known spacers, with four-lobed form, are described in the German patent applications DE 9218132 and DE 29819183, while a spacer with poly-lobed form is the object of another German patent application, DE 19525160. At the state of the art, processes are not currently known for laying said spacers other than by manual procedure. As can be imagined, such procedure leads to much waste of time and human resources, and therefore is not economically advantageous for the construction company. The object of the present finding is that of defining a semi- automatic process for laying the spacers that substitutes the manual methods used up to now.

According to another object, the present finding defines a packaging and handling mode and product of the aforesaid spacers before they are laid.

The finding, object of the present invention, achieves the pre- determined objects since it concerns a process for the semiautomatic laying of spacers for cement structures comprising a conveying step of the spacers in suitable means, for example a load hopper, a orientation step of the spacers, a stacking step of the spacers so to form a cartridge of about 50 pieces, and an actual laying step in which the single spacer is separated from the cartridge and shot into its final position by means of a gun similar to the nail-shooter guns or the like.

The finding also has, as object, the spacer-carrying cartridge, which is formed at the end of the stacking step of the single spacers and is used in the gun as a magazine.

These and other advantages will be evident from the detailed description of the invention, which will make specific reference to the tables 1/2 and 2/2 in which a positively non-limiting preferred embodiment is represented of the present finding. In particular:

• Fig. 1, in views "a" and "b", respectively represents a perspective view of a spacer of circular form and the plan view of the same;

• Fig. 2, in views "a" and "b", respectively represents a perspective view of a spacer of square form and the plan view of the same;

• Fig. 3 depicts the three-dimensional view of the circular spacer with a joint made directly on the spacer;

• Fig. 4 shows the circular spacer with disposable central sealing rod; • Fig. 5 reproduces the cartridge composed of stacked spacers with joint;

• Fig. 6 represents the stacked spacers in the magazine;

• Fig. 7 shows the pneumatic gun complete with magazine;

• Fig. 8, in views "a","b", and "c", respectively represents three perspective views of the magazine;

• Fig. 9, in views "a" and "b", respectively represents two sections of the magazine.

As stated above, the spacers of the invention are elements made of plastic material of circular, poly-lobed, square, rectangular or similar form that are fit by slight interference on the reinforcement bars of the cement according to pre-established length intervals, so to determine, by virtue of their radial dimension, the size of the bar cover. A non-limiting example of such spacers is shown in Figs. 1 and 2. The spacer is indicated with 1, 2 indicates the portion of the spacers that is mounted by interference on the reinforcement bar of the cement. The process for the semi-automatic laying of said spacers comprises a first production step of the spacer by means of moulding or another suitable method. Then, the spacers are conveyed in suitable means, for example a load hopper, where the orientation of the spacers is achieved as well as the stacking

of the same in order to form a cartridge 6 comprising a plurality of pieces, preferably from 30 to 50. The stacking modes of the spacers for forming a cartridge can be of different type. For example, a joint 3, 4 made directly on the spacer (Fig. 3) with male-female coupling or a disposable central sealing rod 5 (Fig. 4). Both solutions achieve both the orientation and stacking by interference of the spacers.

Said cartridge 6 (Fig. 5), thus obtained, is subsequently packaged in a disposable covering, for example paper, transparent film or another material with a very low melting point, and is offered for sale to construction companies in this manner. The laying step of the spacers is carried out by inserting the cartridge 6 in the magazine 7 of a gun 9 (Fig. 7), for example of the nail- or clip-shooter type. According to a preferred embodiment, it is possible to use a clip- shooter compressed-air gun 9, appropriately modified in the magazine 7 portions with the function of housing and guiding the cartridge and in the ejection portion of the single spacers. Said magazine 7 comprises a container 10, a track 11, elastic thrust means 12,13, a safety hook 14 and at least two slits 15,16. The track 11 is characterised in that it has a trapezoidal or similar section, so as to maintain unaltered the orientation of the cartridge 6 (Fig. 9a). Said container 10 is characterised in that it houses a track 11, thrust means 12, 13; in addition, in the ejection portion of the single spacer, near one end of the track 11 and on two opposite sides, it has two slits 15,16. Said slits 15,16 (Fig. 7),

indispensable for the functionality of the magazine 7, allow the first 15 to couple the magazine 7 with the gun 9 while the second 16 permits the spacer 1 of the magazine 7 to exit, upon receiving thrust from the gun 9 . Said thrust means, such as for example a spring 12 with plunger 13 (Fig. 9b), placed on the track 11 and constrained at one end thereof, permit the advancing of the cartridge 6 on the track 11 towards the slit 16. The safe use of the gun 9 with the magazine 7 is ensured by means of a safety hook and a spacer guide system. Said safety hook 14, housed on the outside of the container 10, near the slit 16, (Fig. 8c), allows locking a reinforcement bar 17 during the laying of the spacers, while a guide means 18 (Fig. 9a), positioned inside the container 10, near the slit 16, permits the exit of the spacer 1 towards the slit 16.

Said gun 9, which thus modified forms a semi-automatic unit 8 for the laying of the spacers, will execute -with every "shot"- the cutting of the interference element between a spacer and the remaining part of the cartridge, in other words it achieves the separation of the single spacer from the cartridge and shoots said spacer in the desired position on the reinforcement bar. The semi-automatic unit 8 thus made is in fact the only construction site device for the positioning of the spacers. Of course, it is also possible to organize the construction site in a different manner, with additional semi-automatic units 8. In other words, mounting stations may be provided for in construction

sites equipped with additional semi-automatic units 8, through which the steel trellises to be worked can move. In any case, no matter which embodiment idea is adopted, this process eliminates the manual part of the laying operation, thus obtaining considerable time and human resource savings.