[0001] This invention relates to a chisel comprising a handle, a metal shaft projecting
forwardly of the handle and a chisel blade on the front end of the shaft.
[0002] Such a chisel is well known for use in chiselling wood and similar material.
[0003] According to the invention, the chisel is characterised in that the blade is releasably
clamped to the shaft so as to be replaceable.
[0004] The invention will be described by way of example with reference to the drawings,
wherein:-
Fig. 1, Fig. 2 and Fig. 3 are respectively a front elevation, a side elevation and
a rear elevation of a chisel embodying the invention;
Fig. 4 corresponds to Fig. 1, but with a removeable spare blade holder removed from
the handle;
Fig. 5 is a section on line V-V of Fig. 4;
Fig. 6 is a section on line VI-VI of Fig. 1;
Fig. 7 illustrates the spare blade holder alone, containing two spare replacement
blades;
Fig. 8 is an enlarged section on line VIII-VIII of Fig. l;
Fig. 9 is a partial illustration of the front end of the chisel, with the clamping
member omitted;
Fig. 10 illustrates the chisel being held in the left hand, with the clamping member
pivoted aside, and a blade being inserted or withdrawn by the right hand;
Fig. 11 illustrates a strip of blades for the chisel; and
Fig. 12 illustrates a number of alternative blades for the chisel.
[0005] Referring to the drawings, the illustrated chisel 10 comprises a handle 11, a metal
shaft 12 projecting forwardly of the handle 11 and a chisel blade 13 on the front
end of the shaft 12. The chisel blade 13 is releasably clamped to the shaft 12 so
as to be replaceable. The blade 13 is releasably clamped to the shaft 12 by an elongate
springy member 14 which extends along the shaft 12, being pivotably connected to the
shaft 12 by a pivot connection 15 closedly adjacent the blade 13, the pivot 15 taking
the form of a rivet, as shown most clearly in Fig. 8. The springiness of the member
14 is such that its front end 14a bears down strongly upon the blade 13 to clamp the
blade 13 to the shaft 12, whilst the rear end 14b is biased downwardly into a recess
lla in handle 11. To release the blade 13, the rear end 14b of member 14 is lifted
out of the recess lla and member 14 is then pivoted about the pivot 15, as shown in
Fig. 10.
[0006] The blade 13 is located on the shaft 12 by a spigot 12a of shaft 12 locating in a
hole 13a in the blade 13, and by the pivot 15 locating in a notch 13b at the rear
end of the blade 13, as well as the downward pressure of the front end 14a of member
14 when in its normal position as shown in Figs. 1 to 5 and 8.
[0007] The handle 11 has a cavity llb into which a spare blade holder 16 is releasably clipped
by virtue of a small projection llc at the rear end of cavity llb locating in a recess
16a of the blade holder 16 and an integral spring arm 16b of blade holder 16 engaging
the front end wall lld of cavity llb of handle 11. As illustrated in Fig. 7, the blade
holder 16 can hold a number of blades 13c, 13d, for example, of different sizes. One
side 16c of the holder 16 is enlarged and seats correspondingly in the handle 11 as
shown, so that the holder 16 can only be inserted in the handle 11 one way round as
shown.
[0008] Fig. 11 shows a strip of blades 13e, all of the same size, with waste material between
each pair of adjacent blades, whilst
Fig. 12 shows six blades 13f to 13k of progressively increasing widths.
[0009] The chisel 10 can of course be used by anybody, and affords the advantage of the
blade being replaceable either when it gets blunt or a different width blade is required,
or it is desired to remove the blade during non-use for safety or convenience. It
is believed that the "do-it-yourself" handyman in particular will find the chisel
10 useful.
1. A chisel (10) comprising a handle (11), a metal shaft (12) projecting forwardly
of the handle (11) and a chisel blade (13) on the front end of the shaft (12), characterised
in that the blade (13) is releasably clamped to the shaft (12) so as to be replaceable.
2. A-chisel (10) according to claim 1 characterised in that the blade (13) is releasably
clamped to the shaft (12) by a member (14) bearing down upon the top of the blade
(13), the shaft (12) engaging the underside of the blade (13).
3. A chisel (10) according to claim 2 wherein said member (14) is connected to the
shaft (12) by a connection (15) closely adjacent the blade (13).
4. A chisel (10) according to claim 3 wherein said member (14) is pivotable about
said connection (15) for disengagement from and hence release of the blade (13), the
connection (15) forming a pivot.
5. A chisel (10) according to claim 3 or 4 wherein the connection (15) is adapted
also to locate the blade (13) by engaging in the blade (13).
6. A chisel (10) according to any one of claims 2 to 5 wherein said member (14) extends
along the shaft (12).
7. A chisel (10) according to any one of claims 2 to 6 wherein said member (14) is
springy.
8. A chisel (10) according to a combination of at least claims 1, 2, 3, 4, 6 and 7
wherein a rear end (14b) of said member (14) is located by a portion (lla) of the
handle (11).
9. A chisel (10) according to any preceding claim wherein a spigot (12a) on the shaft
(12) locates in a cutout (13a) in the blade (13).
10. A chisel (10) according to any preceding claim wherein the handle (11) stores
replacement blades (13).
11. A chisel (10) according to claim 10 wherein a blade storage cartridge (16) is
fitted to the handle (11).
12. A chisel (10) according to claim 11 wherein the cartridge (16) is moulded in one
piece of plastics with an integral spring (16b) to locate it releasably in the handle
(11).
13. A chisel (10) according to claim 10, 11 or 12 wherein the blades (13) are of different
sizes.