Mortising tool for slotting machines, particularly for laminated wood beams and the like

Abstract: A mortising tool for slotting machines, particularly for laminated wood beams and the like, which comprises a guide (1) which is meant to form a mortise in association with a slotting machine and is constituted by an elongated body which has a shaped head; the guide (1) supports, along its perimeter, a slot milling chain (2) which can move in a given direction of rotation around the guide. Furthermore the slot milling chain (2) is supported by antifriction means (3) which are arranged along the head and at least one long side of the guide (1), in order to allow easier sliding of the milling chain (2) and both head and side milling with the chain.

Description: The present invention relates to a mortising tool for slotting machines, particularly for laminated wood beams and the like. More particularly, the invention relates to a mortising tool for forming slots or so-called mortises in laminated wood beams or in other materials in which slots must be formed. Conventionally the term "laminated wood" describes the superimposing and gluing of a plurality of layers of wood in order to form elements having the intended cross-section to be used, for example, as load-bearing beams for building structures and the like. Said beams usually have a considerable cross-section and must be connected to each other for construction purposes. Connection among the various beams is achieved by means of inserts generally constituted by metal plates which are placed in slots or mortises formed in the surface of the beam, so that one half of the insert is thus inserted into the slot of one beam and the other half is inserted in the slot of the beam to be connected to the first one. The plates are then bolted to the beams, thus providing a stable coupling. Suitable machines are used to form the slots; they are attached to the beam to be machined and have a tool which consists of a guiding plate around the perimeter whereof a slot milling chain is provided which can move, close to the guiding plate that supports it, in a preset direction of rotation. The guide provided with the chain is constituted by an elongated flat body in which one end or head is meant to bite into the wood of the beam in order to form the slot and the chain has, for this purpose, teeth to remove the wood. Said tools are used successfully to form slots whose width is equal to the width of the guide and thus to the size of the head. However, when it is necessary to form larger slots (as usually occurs), it is necessary to insert and extract, along a same axis, the guide provided with the milling chain and thus form multiple mutually adjacent slots which then merge to form the slot having the intended width. Although this process is onerous from the point of view of time and work, it is necessary because the guide provided with the chain works adequately only along the head portion, which is considerably smaller than the width of the guide. The reason for this is the fact that the slot milling chain encounters friction as it moves, due both to contact with the material to be removed and most of all to contact with the edge of the guide by which said chain is supported. The friction encountered by the head of the guiding plate, however, is such that it is overcome by the force of the motor that turns the chain and therefore milling performed with the head is easy. On the contrary, the friction encountered by the chain segments arranged along the sides of the guide is such that it jams the chain and prevents it from sliding. Therefore, conventional tools can work exclusively by insertion and extraction, so that the head of the guide is in contact with the wood, but the guide cannot be inserted and then moved laterally because its sides are unable to cut the wood in any way since, as mentioned earlier, the slot milling chain jams when it bites into the wood to be removed. Cutting tools are disclosed in prior art documents US-1 892 246, FR-820 460, DE 3607010, FR-2 187 502, FR-722 595, CH 165,565, DE 32 11 627 and DE 12 30 194. However, none of them refers to a mortising tools and address the problem of performing lateral cutting to define slots of any width inside a wood beam. The aim of the present invention is to provide a mortising tool for slotting machines, particularly for laminated wood beams, which is capable of forming a slot of chosen width in a beam without having to extract and reinsert the tool, head first, in the beam in which the slot must be formed. Within the scope of this aim, an object of the present invention is to provide a mortising tool for slotting machines, particularly for beams made of laminated wood or other materials, which is capable of cutting both with its head and with at least one long side of the guiding plate. Another object of the present invention is to provide a mortising tool for slotting machines, particularly for laminated wood beams, which can work with both sides of the guide as well as with the head of said guide. Another object of the present invention is to provide a mortising tool which is highly reliable, relatively easy to manufacture, and at low costs. This aim, these objects and others which will become apparent hereinafter are achieved by a mortising tool for slotting machines, particularly for laminated wood beams and the like, as defined in claim 1. Further characteristics and advantages of the invention will become apparent from the following detailed description of a preferred but not exclusive embodiment of the device according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a partially cutout view of the guiding plate provided according to the invention; and Figure 2 is a sectional view, taken along the plane II-II of Figure 1. With reference to the above figures, the mortising tool according to the invention, generally designated by the reference numeral 100, comprises a guiding plate or guide 1, constituted by a flat elongated body which is substantially trapezoidal; a slot milling chain 2 is arranged around its perimeter and rotationally slides around the guide 1 and in contact therewith. The milling chain 2 is formed, in a conventional manner, by links provided with teeth 4 which are meant to mill the beam or element in which the slot must be formed. The teeth 4 are arranged so as to protrude from the lateral surface of the guide 1 and are staggered along the extension of the guide 1. The guide 1 supports a plurality of antifriction means, advantageously provided by bearings 3 which assist the sliding of the slot milling chain 2 along the guide 1. The bearings 3 are arranged so as to lie flat on the guide 1 and protrude slightly from the edge of said guide, so as to support the milling chain 2 and thus prevent its contact with the edge and therefore prevent it from jamming due to the considerable friction that is generated. Figure 2 illustrates in detail, in a sectional view, a bearing 3 which supports the chain 2. The reference numeral 5 designates one of the pivots that form each link of the chain 1, while the reference numeral 6 designates covering plates accommodated in recesses 8 formed by the guide at the end of through holes which accommodate the bearings 3; screws 7 are also provided for locking the plates 6 and for centering the bearings. The chain 2 thus protrudes from the covering plate 6. The tool 100 is suitable to be connected to a slotting machine (not shown), in which a motor drives the chain 2 rotationally along the perimetric extension of the guide 1. The slotting machine is disclosed in a copending patent application in the name of the same Applicant. The bearings 3 are advantageously closely spaced along the cutting side and the head of the guide 1, while on the opposite side of the guide, not affected by cutting, a single bearing is provided. At the head two bearings 4 are provided which are arranged at the corners of said head because the centrifugal force generated by the rotation of the slot milling chain 2 is greater proximate to the head and therefore the chain would tend to separate from the edge of the guide 1. The operation of the tool according to the invention is apparent from the above description and it is evident that it is possible to provide slots of any width, since the tool, once inserted in the wood with the head in the cutting position, can be moved laterally so that cutting is performed by one of the sides of the guide 1, i.e., the side provided with closely spaced bearings 3. In practice it has been observed that the tool according to the invention fully achieves the intended aim and objects, since it allows to provide slots or mortises without having to continuously insert and remove the blade of the tool. The tool thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept. Thus, for example, it is possible to provide a plurality of bearings on both sides of the guide 1, so as to allow the guide to move both to the left and to the right, improving its versatility. Finally, all the details may be replaced with other technically equivalent elements. In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A mortising tool (100) for slotting machines, particularly for laminated wood beams and the like, comprising a guide which is meant to form a mortise slot, said guide having an elongated body with a shaped head and a slot milling chain (2) supported along the perimeter surface of said guide and being movable in a given direction of rotation therearound, and said slot milling chain being supported by antifriction means constituted by a plurality of bearings (3) arranged along the head and along at least one long side of said guide body, characterized in that said bearings are accommodated in a plurality of through openings formed in said guide body and ending with recesses (8) into which plates (6) can be arranged for covering and retaining said bearings. The mortising tool according to claim 1, characterized in that said bearings (3) are arranged so that they protrude from the edge of said guide so as to keep the slot milling chain (2) spaced from said edge during its motion. The mortising tool according to claim 1, characterized in that said plurality of bearings (3) are mutually closely spaced. The mortising tool according to claim 1, characterized in that it further comprises screw (7) for locking said plates (6) for covering and centering said bearings (3).

Inventors: FE SILVIO, LAMA ARTURO, FE', SILVIO, LAMA, ARTURO
Applicants: LAMA ARTURO, LAMA, ARTURO
Application year: 1998
Main classification: B27F5
IPC codes: B27B17, B27F5