FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a hand saw having a handle and an elongated saw blade connected thereto and having saw teeth along one long side thereof and a back along the opposite other long side thereof, said back being provided with a back ledge transferable between a first position, in which it stiffens the saw blade substantially, and a second position, in which it is moved away, in which it is adapted to allow sawing through ma¬ terials having a thickness exceeding the height of the saw blade.

The invention relates to all types of hand saws used for sawing through material of all conceivable types, although the invention is particularly directed to conventional hand saws, especially of the fog saw type, for sawing in different wood materials.

It is desired to have a said back ledge on such hand saws for increasing the stability of the saw blade and reduce vibrations therein when sawing and by that improve the accuracy and the efficiency when sawing. However, a disadvantage of having such a back ledge on the saw blade is that it is in the way when sawing in thicker material pieces, since it forms a stop defining a maximum depth reachable by a saw cut achieved by the saw.

Thus, it is at times desired to not have any such back ledge.

A number of solutions have been proposed for simultaneously meeting said two desires mentioned above.

GB 154161 1 describes a hand saw having a removable back ledge, which may be pushed onto the back of the saw for trans¬ ferring it between said two positions. However, this means that the back ledge has to be carried along separately, and the transfer between the two positions gets comparatively irritating to carry out.

GB 2997 describes in its turn a hand saw having a back ledge being pivoted with respect to the saw blade in the region of the handle for enabling pivoting of the back ledge between said two positions. A drawback of this solution is that when the back led¬ ge is pivoted away it may be both in the way and easily subject¬ ed to damage or hurting the user.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a hand saw of the type defined in the introduction, which finds a remedy to the inconveniencies mentioned above of such hand saws already known and means an improvement with respect to the arrange¬ ment of the back ledge.

This object is according to the invention obtained by arranging the back ledge in a hand saw of the type defined in the introduc- tion displaceable in the longitudinal direction of the saw blade along the back of the saw blade from said first position and rear- wardly at least partially beyond the handle end of the saw blade for obtaining said second position of being moved away, and conversely.

By arranging the back ledge displaceable along the back of the saw blade in this way a conversion between the two positions may easily and reliably be obtained. Thus, the back ledge may be in said first position in which it stiffens the saw blade sub- stantially for obtaining the advantages mentioned above of in¬ creased stability of the saw blade when sawing through thinner

material pieces, and when quite suddenly a deep saw cut has to be applied the back ledge may easily be displaced in and at least partially beyond the handle end of the saw blade and the sawing may immediately be continued for obtaining the deeper saw cut.

According to another preferred embodiment of the invention the back ledge is in said second position of being moved away ad-apted to extend in the direction from the handle out over a part of the saw blade normally not used for sawing. A certain stabilization is by that obtained already in said second position, and a displacement of the back ledge from this position being not just as long as required for obtaining a position in which it stiffens the saw blade substantially, as would the back ledge be moved completely away from the saw blade in said second posi¬ tion. It has namely been found out that the back ledge is not in the way in a such said second position, but deep saw cuts may nevertheless be obtained.

According to another preferred embodiment of the invention said part of the saw blade is in the longitudinal direction of the saw blade shorter than 15 cm, preferably shorter than 10 cm. It has in the practice turned out that the back ledge without any pro¬ blem may extend at least 5 cm out from the handle in said sec- ond position, and usually at least 10 cm from the handle in this position, and in some cases nearly 15 cm out from the handle in this second position, and nevertheless not constitute any obsta¬ cle when sawing very deep saw cuts having a depth exceeding the height of the saw blade.

According to another preferred embodiment of the invention the back ledge is transferable between said two positions by dis¬ placement in the longitudinal direction of the saw blade by a distance of 5-15 cm, preferably 5-10 cm. It has turned out that a displacement of the back ledge over this distance is completely sufficient so as to, starting from the second position in which it

moved away, which allows sawing through materials having a thickness exceeding the height of the saw blade, obtain a sub¬ stantial stiffening of the saw blade stabilizing the saw blade.

According to another preferred embodiment of the invention the saw has a first stop member connected to the handle and adapt¬ ed to co-operate with a first stop piece connected to the back ledge for defining said first position when the first stop piece upjon displacement of the back ledge reaches the first stop member. It is by that avoided that the back ledge may be dis¬ placed further along the back of the saw blade than to said first position, so that this position may be reliably defined.

According to another preferred embodiment of the invention the saw has the second stop member connected to the handle and adapted to co-operate with a second stop piece connected to the back ledge for defining said second position when the sec¬ ond stop piece upon displacement of the back ledge reaches the second stop member. It is by that obtained that the back ledge upon displacement thereof from the first to the second position not may reach longer than to the second position, and also this position gets well defined.

According to another embodiment of the invention the handle has an elongated channel-like recess extending in the longitudi¬ nal direction of the saw blade and in which the back ledge may be inserted for transfer between said two positions. Such a channel-like recess is very advantageous, since it enables a comfortable moving away of the back ledge into the handle in said second position and simultaneously a secure guiding and holding of the back ledge during the displacement thereof be¬ tween said two positions and in the two positions.

According to another preferred embodiment of the invention the back ledge and the recess are adapted to co-operate so that the end of the back ledge closest to the handle is kept inside the

recess against leaving the recess in said first position. The stop members and the stop pieces mentioned above may in this way be realised by very simple and reliable means.

According to another preferred embodiment of the invention the recess has a bottom adapted to form said second stop member for defining the second position of the back ledge, so that this stop member gets very simply and reliably defined.

According to a further preferred embodiment of the invention the outer end of the _/ back ledge most remote to the handle is pro¬ vided with gripping means so as to facilitate pushing and/or pulling of the back ledge along the back of the saw between said two positions.

According to another preferred embodiment of the invention the hand saw comprises locking members controllable through the gripping means for locking the back ledge to the saw blade against displacement therealong. There is by that no risk that the back ledge unintentionally will be transferred from one of the positions to the other or any position therebetween when handl¬ ing the saw.

Further advantages as well as advantageous features of the in- vention will appear from the following description.

BRIEF DESCRIPTION OF THE DRAWING

With reference to the appended drawing, below follows a spe- cific description of a preferred embodiment of the invention cited as an example.

In the drawing:

Fig. 1 is a side elevation of a hand .saw according to a preferr¬ ed embodiment of the invention with a back ledge in said second position in which it is moved away, and

Fig. 2 is a partially sectioned view of a part of the hand saw according to Fig. 1 with the back ledge in said position in which it stiffens the saw blade substantially.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

A hand saw 1 according to a preferred embodiment of the inven¬ tion is shown in Fig. 1. This is of the fog saw type and accor¬ dingly of principally conventional type for hand sawing for cutt- ing or applying saw cuts in wood and the like. It has in a con¬ ventional way a handle 2 for gripping the saw, usually by a hand, and a saw blade 3 with saw teeth 4 along one long side thereof and a back 5 along the opposite other long side.

The features characterizing for the invention will now be described while making reference at the same time also to Fig. 2. A back ledge or rim 6 of any comparatively stiff material, such as hard plastic, is adapted to receive the back 5 of the saw blade in a slot therein. This back ledge is arranged to be transferable between a first position according to Fig. 2 in which it stiffens the saw blade substantially and a second position according to Fig. 1 of being moved away, in which the back ledge is adapted to allow sawing through materials having thickness exceeding the height of the saw blade. The back ledge extends in this second position according to Fig. 1 in the direction from the handle out over a part of the saw blade normally not used for sawing, and this is in the present (see Fig. 1 ) about 8 cm.

The outer end of the back ledge remote to the handle is pro¬ vided with gripping means 7 for facilitating pushing and/or pull-

ing of the back ledge along the back of the saw between said two positions. This gripping means 7 may then also be pivoted between the two positions shown in the figures for controlling a locking member associated with the gripping means for locking the back ledge to the saw blade against displacement there- along (the position of the gripping means according to Fig. 2).

The handle 2 has as appears from Fig. 2 an elongated channel- like recess 8 extending in the longitudinal direction of the saw blade and in which the back ledge may be inserted for transfer¬ ring it between said two positions. The bottom 9 of the recess forms a second stop member for defining the second position of the back ledge and adapted to co-operate with a second stop piece 12 in the form of end surfaces of the back ledge, while in the end of the recess 8 closest to the blade a first stop member 10 in the form of a heal is arranged to co-operate with a first stop means 11 arranged at one end of the back ledge in the form of a step for defining the first position of the back ledge and prevent the back ledge from unintentionally leaving the channel-like recess. This channel-like recess 8 enables in this way preferably a displacement of the back ledge by 5-15 cm in the present case about 8 cm, in the longitudinal direction of the saw blade.

The function of the saw according to the invention with respect to handling of the back ledge appears as clearly as desired from the description above, but it will nevertheless here be briefly summarized. When sawing through thick materials requiring a saw cut with a depth exceeding the height of the saw blade it is preferably started with the back ledge in the first position for re¬ ducing vibrations of the saw blade, which is particularly good for the first saw strokes. When it has then been sawn further down into the wood and the ledge starts to be in the way the ledge is pulled back and locked in the second position according to Fig. 1. When then for example thin boards or the like are to be sawn it is desired to obtain a high stability of the saw blade so that

the result of the sawing is improved and the life of the saw pro¬ longed. The gripping means 7 is then for obtaining this pivoted for unlocking the locking member and the back ledge 6 is pulled/ pushed in the recess 8 and along the back 5 of the saw blade out to the position according to Fig. 2, where the gripping means 7 is pivoted downwardly and the back ledge 6 is locked with respect to the saw blade.

The invention is of course not in any way restricted to the pre- ferred embodiment described above, but many possibilities to modifications thereof would be apparent for a person with skill in the art without departing from the basic idea of the invention as defined in the appended claims.

It would for example be possible to obtain locking of the back ledge in the two positions in another way then described here- above, for example divergence or convergence of the channel- like recess and the end of the back ledge closest to the handle.

As already appears from the introductory portion of the descrip¬ tion the saw according to the invention may have a totally differ¬ ent appearance with respect to the handle and the saw blade than shown in the appended figures.

It is within the scope of the invention to be able to transfer the back ledge into several different positions between two extreme positions, and it would be possible to for example call positions close to one of the extreme positions for first positions, and con¬ versely for second positions. In the embodiment shown in the figures an infinite number of fixed positions of the back ledge are obtainable thanks to the design of the locking member.