AN ACCIDENT PREVENTION DEVICE FOR EDGE TRIMMERS

Abstract: This invention concerns an accident prevention device for edge trimmers consisting of a protection cover comprising a bell (1) mounted on the chuck-holder head (3) both in horizontal and slanted position. This tooling may also include knives (6) with backward curving profile.

Description: Description An accident prevention device for edge trimmers. This patent application concerns an accident prevention device for edge trimmers consisting of a protection cover having different positions and special warped profile. Current edge trimmers available on the market are all constructed on the same principle whereby the cutting tool is fixed on a chuck housed in a head positioned at the base of a long tubular rod in which the shaft operating the chuck, is fitted and rotates, driven by a small combustion engine mounted at the other end of the rod. The worker holds the edge trimmer from a handle fitted halfway along the rod which, when used is held in a slanted position so that the chuck-holder head - positioned vertically or slightly sub-vertically - brushes against the ground at a certain distance from the feet of the worker. Generally, said edge trimmers are supplied with two different cutting tools which can be mounted on the edge trimmer chuck; the first is a small disk from which a fishing line projects which spins to cut grass and tender shrubs; the second consists of a knife which is fixed to the centre of the chuck providing a pair of diametrically opposed cutting blades. Both the fishing line disk and the knife are generally not protected by a cover so that there is a very high risk of accidental cuts to the worker when using these trimmers. The parts of the body most exposed to the accidents are obviously the legs which may get in the way of the cutting tool or be hit by stones or other objects hurled by the cutting tool. Over and above this, if the trimmer knife strikes stones or other hard objects, the blade may break and, due to the absence of a protecting cover, the pieces spinning at a very high speed will be flung to become dangerous missiles which can very seriously hurt the persons or property they strike. Due to the above, protection screens have recently been designed consisting of a sheet plate bell installed on the check-holder head and housing the cutting tool whose axis of rotation is coincident with the axis of symmetry of the bell. If the tool breaks accidentally, the spinning fragments are intercepted and stopped in the protection bell which also restrains blunt bodies thrown by the cutting tool. The use of these protection bells also allows the worker to give a more even cut to the lawn; it is evident that by sliding the protection bell on the ground the lawn will automatically be cut more evenly at a height from the ground equal to the difference in height between the bottom edge of the bell and the rotation plane of the cutting tool, without any particular effort or attention on the part of the worker. Although the use of said protection covers undoubtedly ensures that the same may be used in total safety, it does however limit the field of application and efficiency of the trimmer. First and foremost it is evident that if the cutting tool is housed in a bell it is impossible to reach the trunk of small shrubs at the base which would interfere with the outer edge of the cover. It is also impossible to use the trimmer to cut the smaller branches of trees which can be cut only by an unprotected blade. Even when cutting grass however the use of said bells may become a problem at times, for instance when cutting grass which is very high, such as grass for fodder. In these cases, the outer edge of the bell will inevitably bend the grass making it difficult for the cutter to efficiently cut the blades of the grass. The purpose of this invention is to design a new protection cover model for trimmers which is more versatile and efficient to use with respect to those currently existing on the market. A further scope of this invention is to design a cutting tool which can prevent accidents and is safe to use. The protection cover according to the invention consists of bell realised in sheet plate or other plastic materials characterised by two holes, a centre hole and an eccentric hole, at which the chuck-holder head of the trimmer may be fitted when required. When the chuck-holder head is fitted to the centre hole, the cutting tool is perfectly centred in the bell therefore providing a high level of safety to the operator should the tool break or stones and other objects be flung by the tool. If the chuck-holder head is fitted into the eccentric hole of the bell, one of the ends of the cutting tool projects beyond the outer edge of the bell, whose axis intersects that of the chuck-holder head. In this operating position, the bell in question acts as a protection screen for the operator for only a span of the semi-circumference; this reduced degree of protection however increases the versatility and efficiency of the edge trimmer which can also be used to cut shrubs and high grass, to prune trees and trim hedges, thanks to the fact that the cutting tool projects beyond the outer edge of the bell. The device according to the invention also includes a special cutting tool consisting of a cutting blade suitably profiled and screwed to a support disk by means of interposing inserts which give the blade a warped profile which, as the knife rotates, produces an active or passive lift, according to the position of the inserts selected by the operator. In the case of active lift, the operator no longer has to lift the trimmer off the ground, in that the same is virtually self-supporting. The fact that the knife is fixed on a support disk, which is in turn fixed to the chuck by means of a centre bolt, reduces the risk of accidents if the knife breaks accidentally along a transverse line passing through the centre hole of the knife provided for the intersection of the fixing bolt to the chuck. In this unfortunate event, the two parts of the knife will in fact remain attached to the above support disk without the possibility of being dangerously flung around, as on the hand occurs, with the use of standard knives which are fixed directly onto the chuck without the interposition of the support disk. Regarding the special profile of the knife blades, it should be noted that the profile of the same curves backwards with respect to the rotation direction of the knife; this special profile of the blades allows the knife to perform a gentle and progressive scissors-like cut, rather than a shearing cut as in the case of the straight bladed knives used to date. The slicing rather than shearing effect of the knife according to the invention indirectly provides major accident prevention safety in that the curved cutting blade, in the case of impact, sustains a less violent strain. This reduces the probabilities that the knife will break and all the consequent risks this entails. The centrifugation of the bodies flung by the rotating knife is also indirectly less violent and thus less dangerous. For major clarity the description of the accident prevention device according to the invention continues with reference to the enclosed drawings which are intended for purposes of illustration and not in a limiting sense, whereby: - fig. 1 is an axonometric and exploded view of the different components of the accident prevention device according to the invention; - fig.2 shows the device according to the invention with the chuck-holder head of the trimmer fitted into the centre hole of the protection bell; - fig . 3 shows the device according to the invention with the chuck-holder head of the trimmer fitted into the eccentric hole of the protection bell. With particular reference to figure 1 , the accident prevention device in question consists of a bell (1 ) having two identical holes, one at the centre (1 a) and the other eccentric (1 b) into which the threaded pin (2a) fitted at the top of a casing (2) designed to house the chuck-holder head (3) of the trimmer, may be fitted as required. Said casing (2) is for this purpose provided with a notch (2b) designed to house the nosepiece (3a) projecting from a side of the chuck-holder head (3) into which the rod handle (M) of the trimmer is fitted. In this regard it should be noted that the hole of the bell (1 ) not occupied by the threaded pin (2a) of the casing (2) is crossed by said handle (M) as shown in figs. 2 and 3. The pin (2a) is stopped in one of the two holes (1 a or 1 b) by a nut (4a) and a counter-nut (4b), both screwed to said pin (2a), one fitted in the bell (1 ) and the other fitted outside the bell (1 ) which is therefore fixed between the nut (4a) and counter- nut (4b). The chuck-holder head (3) is stopped in the casing (2) by a clamp (5) wound tightly around the edge of the casing (2) base. The device in question also includes a knife (6) fixed above a support disk (7) by means of bolts (8) fitted into holes (6a) on knife (6) and through corresponding holes (7a) on disk (7). The connection of the disk (7) to the chuck-holder head (3) is by means of a washer (10) positioned under the disk (7) and provided on its upper face with a collar (10a) housing precisely in the centre hole (7b) of disk (7) and the centre hole (6b) of knife (6). A bolt (11 ) fitting into wash (10) and screwed to the chuck-holder head (3) fixes the disk (7) against the chuck-holder head. Disk (7) is provided with perimeter holes (7c) into which bolts (12) are fitted and whose head (12a) remains between disk (7) and knife (6) so as to warp knife (6) so that the same may, during rotation, produce an active or passive lift, according to how the operator positions said bolts (12).

Claims: Claims 1 ) An accident prevention device for edge trimmers consisting of a protection cover which can be placed in different positions and a warped blade having a special profile characterised by: - a bell (1 ) provided with two identical holes, one at the centre (1 a) and the other eccentric (1 b), designed to house the cutting blade; - a casing (2) designed to precisely house the chuck- holder head (3) of the trimmer and terminating at the top with a threaded pin (2a) designed to fit into one of the two holes (1 a and 1 b) as required, and on which a nut (4a) and a counter-nut (4b) are screwed; - means for fixing the casing (2) outside the chuck- holder head (3). 2) An accident prevention device for edge trimmers according to the previous claim characterised in consisting of a knife (6) fixed on a support disk (7) by means of bolts (8) fitted into holes (6a) on the knife (6) and through the corresponding holes (7a) on the disk (7); it being provided that the disk (7) is connected to the chuck-holder head (3) by means of a bolt (11 ) fitted into a washer (10), placed under the disk (7) and provided on its upper face with a collar (10a) which is precisely housed in the centre hole (7b) of the disk (7) and the centre hole (6b) of the knife (6) . 3) An accident prevention device for edge trimmers according to claim 2 characterised in that the disk (7) is provided, in addition to holes (6a), with perimeter holes (7c) into which bolts (12) are fitted and whose head is positioned between disk (7) and knife (6) so as to warp the knife (6). 4) An accident prevention device for edge trimmers according to the previous claims characterised in that the knife (6) features blades whose profiles are curved backwards with respect to the rotation direction of the knife.

Inventors: SEBASTIANI LUCIANO, SEBASTIANI, LUCIANO
Applicants: S L A M S R L, SEBASTIANI LUCIANO, S.L.A.M. - S.R.L., SEBASTIANI, LUCIANO
Application year: 1997
Main classification: A01D75
IPC codes: A01D75, A01G3