The invention relates to a method of lath profiling used for making parquets and to a squaring machine which makes such a method for profiling laths.
It is known that, in order to make parquets, wood laths are currently used joined one with each other through joints made on their lateral sides.
In particular, suitable squaring machines make on one lateral side of the laths a male profile joint and on the opposite lateral side a female profile joint.
The joint profiles are connected one with each other and the floor surface is overlaid through a plurality of laths alongsided and connected one with each other joining the male element of each one in the female element of the adjacent lath.
The squaring machines used (representing the closest prior art disclosing the preamble of method claim 1 and the preamble of device claim 6) comprise a frame provided with a plurality of operating units, each one having a rotating tool with a profile suitable for making in the lath the desired profile.
The squaring machine is provided with a chain on which the working laths are head - tail aligned one after each other.
The chain advances continuously along the longitudinal direction of the frame and the laths are hold adherent through suitable pressure means generally made by an higher track.
During the advance the laths are worked in correspondence with the ribs by the operating units tools located two by two one opposed with another and operate at the same time on both ribs of the laths themselves.
According to the known technique, the lath advancement chains are composed by a plurality of grids one pivoted after another in order to make a closed ring which is advanced along the longitudinal direction of the frame through gears, being at least one of them motorized, which engage the grids.
The chains are provided with slipping pads, which lean on sliding guide integral with the frame and internal to a protection case.
The case width is lower than the finished width of the lath which is easily manufactured in correspondence with the ribs of the shaped tools applied to the operating heads.
In particular, the parts of the lath to be manufactured project with respect to the case containing the chain and therefore they can be easily reached by the operating heads tools, which operate rotating on parallel planes or perpendicular with respect to the working surfaces.
The chains used are slipping chains of the known type, built by the same applicant of the present patent.
A disadvantage of the slipping chains is the limited speed of advance they permit, varying between 40 and 45 m/minute.
Squaring machines are known, which have advancing speeds reaching also 60/80 m/minute using slipping chains.
These, in a similar way, are made by a plurality of grids one along another which, instead of sliding on the slides integral with the machine frame through pads, roll on the slides themselves through rolling bearings placed on the ends of a pin located transversally to each grid.
In this way the sliding friction of the pads is substituted by the rolling friction of the bearings, obtaining a great wear reduction and also a great reduction of the need of maintenance intervention.
However the rolling chains have the disadvantage of having widths higher than the correspondent slipping chains.
Therefore they cannot be used on squaring machines which have to produce parquet laths with the same finished width of that produced on squaring machines provided with slipping chains.
In fact, if the chain width, and therefore the case width holding it, is higher than the finished width of the working laths, the tools cannot reach the lath lower surface because of the obstacle due to the presence of the case protecting the chain.
In order to work on such squaring machines laths having a finished width lower than the case width protecting the advance chain, it is necessary to locate two squaring machines and work on the laths placing them with their ribs projecting alternatively on one side and on the other, with respect to the covering case of the advance chain of each squaring machine.
Alternatively it is possible to manufacture the laths passing them twice along the same squaring machine and, during each passage, to manufacture a lath rib projecting laterally from the protection case of the chain.
It can be understood that both ways of operating imply, as well as a cycle time extension and greater difficulties of equipping the machines, even a lower dimensional precision on the finished product.
At this regard, it has to be remembered that if the working panels are of the pre-defined type which is not smoothed after its location, the working allowances have to be very narrow (some centesimals), in order to prevent the covering difference which, when the work is finished, would be clearly evident.
The present invention is intended to overcome such disadvantages and limitations.
In particular, it is a first scope of the invention the realization of a method that allows, in a parquet lath squaring machine, the manufacturing of the lath lower surface in areas reentering with respect to the protection case width of the advance chain which supports them.
It is another aim of the invention the realization of a squaring machine which, using a rolling chain, can manufacture laths with a width lower than the case width enclosing the chain.
Said aims are reached through the realization of a method for parquet laths profiling placed along a tow chain enclosed in the squaring machine base case provided with a plurality of operating heads which, according to claim 1, comprises the following operations:
According to a preferred form of realization, operating heads, forming longitudinal engravings on both faces and mounted on slanting saddles suitable for advancing the tool slantingly to said lath, are present in the squaring machine.
In the squaring machine according to claim 6 for realizing the method of the invention, the chain supporting the laths is a rolling chain and is provided with a plurality of supporting plates on which they rest the working laths.
Each plate has its width both lower than the case width enclosing the chain and than the distance between the longitudinal engravings on each lath. The plate height is sufficient to define on each side a reentering area with respect to the case housing the chain, which is delimited on the bottom of the case itself, sideways from the plate side and higher up from the lower surface of the working lath.
Such a reentering area allows the entering of the rotating tool slanting to the lath lower surface, on which the longitudinal engravings have to be made.
Advantageously, the raising of the sliding plane of the laths with respect to the case plane housing the chain through a plate having a width lower with respect to the distance between the engravings to be made on the lath, together with the slanting position of the tools, allows the manufacturing of the lath lower surface making on it longitudinal engravings, one distant from another of a lower quantity with respect to the case width housing the chain.
Still advantageously, this allows the use of rolling chains, which are larger than the correspondent slipping chains, but they allow greater manufacturing speeds.
Said aims and advantages will be better explained during the description of a preferred form of embodiment of the invention, which is given as an indicative but not limitative title and is referred to the accompanying drawings where:
As we can see in fig. 1 the squaring machine of the invention, indicated as a whole with 1, realizing the method being also an aim of the invention, comprises a base 2 supporting a plurality of operating heads 3, 4, 5, 6, 7, located one after another.
Each couple of operating heads is formed by two opposite operating heads, each one placed on one side of the squaring machine according to the arrangement seen as a title of example in fig. 17, relative to the first couple of operating heads 3, comprising the left 3a and right 3b heads one opposite to another.
As well as the first couple of operating heads 3 just cited, are recognized, also with reference to fig. 2:
The operating heads manufacture the laths L, which are advanced along the longitudinal direction of the squaring machine in the sense indicated by the arrow 8 of fig. 1 and 2.
In particular, a plurality of laths is located one after another, leaning on a chain 9, which is winded as a ring between a back gear 10 and a shaped front slide 11, where the back gear 10 is rotated by a power group, indicated as a whole by 12.
The chain 9, as we can see in greater detail in fig. 17, is a rolling chain, being composed by plurality of grids 13 linked one with another and of the type per se known, each one having a transverse pin 14 supported on its ends by rolling bearings 15, 16 leaning on respective tracks 17, 18 belonging to the frame 2 of the squaring machine.
The chain 9 is housed on the case 19 belonging to the frame 2 of the squaring machine and each grid 13 of the chain 9 is provided with a supporting plate 20.
Each plate 20 has a datum plane 21 preferably made using a material with a high coefficient of friction, on which the lower surface L' of the working laths L rests.
A presser 22 holds the laths L adherent to the datum plane 21 and therefore also to the grid 13 of the chain.
When the power group 12 advances the chain 9, the laths L move between the operating heads and are manufactured by the rotating tools which the operating heads are provided with.
The profiling method of the laths which are the aim of the invention comprises, with reference to figs. 2 to 16, the following operations:
According to the invention the distance D between the engravings S', S" is lower than the width 24 of the case 19, each engraving being obtained using a rotating tool 3', 3", 4', 4" belonging to one of the operating heads 3a, 3b, 4a, 4b and having the rotating plane 30', 30", 40', 40" slanting with respect to the plane defined by the horizontal plane face L', L" of the lath L.
Ever according to the invention, each supporting plate 20 has its width 23 lower than the width 24 of said case 19 and the sides 25 vertically protruding from the case itself in order to define laterally to each lath L a zone Z limited by the lath L, by the side 25 of said plates 20 and by said case 19, suitable for housing the tools 3', 3" making said longitudinal engravings S' on the faces L' of said laths L leaning on the datum planes 21 of said plates 20.
Preferably after the milling of the male M and female F profiles, these are finished through finishing tools 7', 7", as we can see in figg. 2 and 13 to 15 obtaining finished profiles M', F'.
It is clear that the method and the machine described can undergo variations not cited in the description and not represented in the figures.
Therefore, e.g. the number of operating heads could be different and located differently from what has been shown and described.
Further, the tool and manufacture profiles made on the lath sides could be of a different type from the description, according to the final product we want to obtain.
Referring to the squaring machine, the plates put on the advance chain of the laths could be of a different form or dimensions according to the working laths, but these must have a width not higher than the distance between the engravings to be made on the lower face of the laths and on the case width.
Further, its height must allow the insertion between the laths, the case and the plates of the slanting tools operating the engravings.
We say that said executive variations and other eventual variation not cited, belonging to the claims, are intended as protected by the present claims.