GB2096041A - Cutting implements - Google Patents

Abstract

A scissor action cutting implement having interchangeable blades 10, 11, located on carriers 20 (provided by handle members 21) by means of projections 25, 26 provided on the carriers 20 to engage in holes or sockets in the blades to constrain the blades to move in unison with the respective handle members about a pivot assembly 14 when the latter is assembled to hold the blades and carriers 20 together. The assembly 14 is releasable to allow the blades to be removed for replacement by other, e.g. different forms of, blades. <IMAGE>

Description

SPECIFICATION Cutting implements This invention concerns cutting implements of the kind having arcuately movable opposed blades, such as scissors, snips, shears and secateurs.

It is well know that such implements of good quality have to be made from a durable material which can take a sharp cutting edge, but such materials are expensive. In an attempt to reduce the cost of such implements, scissors have been made which are formed predominantly from a relatively inexpensive material and provided with cutting edge strips, which strips are secured permanently to the adjacent portions of the blades and are formed from a very durable material. However, such scissors can be difficult to re-sharpen; and corrosion can cause the cutting edge strips to become detached from or insecurely attached to the adjacent portions of the blades, thus rendering the scissors inoperative.

According to the present invention there is provided a cutting implement having arcuately movable opposed blades, characterised in that a portion of each blade is provided with a pivot aperture and a plurality of locating sockets; in that a pivot assembly extends freely through said pivot apertures and clamps said end portions together and between handle members; in that each handle member is provided with protuberances which engage closely in the locating sockets of a respective one of the blades to constrain said blade to move in unison with the handle member about the axis of said pivot assembly; and in that said pivot assembly is separable to permit said blades to be removed from said handle members.

Preferably in each blade a first one of said locating sockets is provided in a first zone at or adjacent one end of the portion and a second one of said locating sockets is provided in a second zone of said portion which second zone is spaced apart from the first zone longitudinally of the blade to leave an intermediate zone therebetween, and the pivot aperture is disposed in said intermediate zone.

The sockets and pivots apertures may be arranged so that either blade or only a particular one of the blades, can be fitted to a particular one of the handle members, and so that the blade can only be fitted to the handle member in one specific orientation relative to the handle member.

Each socket is preferably formed as an aperture extending through the blade, and each protuberance is preferably formed as an integral part of the handle member.

The handle members may comprise metal parts provided with apertures or recesses for a users digits, moulded covers, or wood or plastics handles.

The invention enables the blades to be made from a material selected to suit the intended use of the blades; enables the blades to be removed for re-sharpening or replacement; enables the implement to be sold as a combination with one or more sets of spare blades or with alternative types or blade suited to particular purposes; and enables the handle members to be made from any suitable material or materials.

The invention will be described, by way of example, with reference to the accompanying diagrammatic drawings; wherein: Figure 1 shows, in partial cross-section, a first embodiment of cutting implement according to the invention in the form of a pair of shears; Figure 2 shows a portion of one blade of Figure 1 which cooperates with one of two handle members of the shears; and Figure 3 shows, in cross-section, a second embodiment of the invention.

The shears include a pair of blades 10, 11, a pair of handle members 13,13 and a pivot assembly 14.

In the first embodiment each blade 10 or 11 is substantially flat and has a cutting edge 15 which extends from a tip of the blade along a cutting portion of the blade to a mounting end portion 16 of the blade. The portion 16 is provided with a pivot aperture 17 which is disposed between two locating apertures 18 and 19. For ease of presentation, these apertures 17, 18 and 19 are shown with their centres substantially aligned, but the centres may be arranged in the corners of the triangle so that the aperture 17 is offset from a line joining the apertures 18, 19 whilst disposed in a zone between the zones in which the apertures 18 and 19 are disposed.

Each handle member 12 or 13 comprises a carrier portion 20 and a shank portion 21 integral therewith; and a handle 22 is secured to one of the shank portion 21 remote from the carrier portion 20. The carrier portion 20 is provided with a pivot aperture 23 which is disposed between a pair of studs 24 which are rivetted through the carrier portion to provide protuberances 25 and 26 at one side of the carrier portion 20.

The shanks 21 have extensions 27 which abut when the shears are closed.

The pivot assembly 14 comprises a bolt 30, a spring washer 31 and a nut 32. The bolt 30 has a head 33 and a threaded end portion 34 which are connected by a cylindrical intermediate portion 35.

The diameters of the portion 35, the apertures 17 and the apertures 23 are such that the bolt is a close sliding fit in the apertures 23 and a free fit in the apertures 17. The blades 10 and 11 are thrust together and the mounting end portions 16 are held in position upon the carrier portions 20 by a clamping pressure applied by the pivot assembly to the carrier portions. The clamping pressure can be varied by varying the compression applied to the nut 32 to the spring washer 31.

The dispositions and dimensions of the protuberances 25 and 26 are such that the protuberances 25 fit closely into the apertures 18 and the protuberances 26 fit closely into the apertures 19, whereby to constrain the blade 10 to move in unison with the handle member 12, relative to the blade 11 and handle member 13, about the axis of the bolt 30. The height of the protuberances is such that the apertures 18, 19 serve as sockets which accommodate the protuberances so that the latter do not project from the apertures.

It will be readily appreciated that the blades 10 and 11 can be removed by undoing the nut 32, separat ing the handle members 12 and 13 and lifting or knocking the blades from the handle member, so that the blades can be re-sharpened or replaced by new or alternative blades such as short curved pruning blades. The clearance between the bolt and the blades in the apertures 17 serves as a reservoir for lubricant, serves to facilitate assembly of the shears, and serves to reduce the possibility of a build up of rust causing the blades to seize to the bolt.

The invention is not confined to the precise details of the foregoing example, and many variations are possible within the scope of the invention. For example, the or one of the protuberances on each handle member may be formed integrally from the handle member, e.g. the bent up lug 50 shown in broken lines in Figure 2; and the or one of the sockets in each blade may not be of aperture form, e.g. the recess or notch form of socket 51 indicated in broken lines in Figure 2 to receive the lug 50.

However, instead of using rivets, pegs or like inserted members to provide the protuberances, the protuberances are preferably pressed integrally from the handle members in a press to provide cylindrical protuberances 25A and 26A as shown in Figure 3, and preferably the protuberances are formed at the same time as the apertures 23 are formed so that the centres thereof are located with precision. The portion of each blade in which the apertures 17, 18 and 19 are provided, may be a major portion of each blade, if the blades are short, e.g. the pruning blades 10A and 11A shown in Figure 3, which figure also shows that the bolt 30 may be a press fit in the aperture 23 in the bottom carrier portion 20 so as to rotate therewith.

Other modifications are possible. For example, the handle members may have shanks adapted to be gripped or held or may be provided with any suitable form of handle, e.g. to form a cutting implement such a snips, pruners, lawn edging shears, or like scissor action cutter.

The blades are made from high carbon steel to provide durable cutting edges, and the handle members are made from easily worked mild steel, but any respectively suitable materials may be used.

The pivot assembly may include a plain bearing washer below the spring washer, and the nut may be of self locking form.

Claims (8)

1. A cutting implement having arcuately movable opposed blades, characterised in that a portion of each blade is provided with a pivot aperture and a plurality of locating sockets; in that a pivot assembly extends freely through said pivot apertures and clamps said end portions together and between handle members; in that each handle member is provided with protuberances which engage closely in the locating sockets of a respective one of the blades to constrain said blade to move in unison with the handle member about the axis of said pivot assembly; and in that said pivot assembly is separable to permit said blades to be removed from said handle members.

2. An implement as claimed in Claim 1,wherein in each blade a first one of said locating sockets is provided in a first zone at or adjacent one end of the portion and a second one of said locating sockets is provided in a second zone of said portion, which second zone is spaced apart from the first zone longitudinaliy of the blade to leave an intermediate zone therebetween, and the pivot aperture is disposed in said intermediate zone.

3. An implement as claimed in Claims 1 or 2, wherein the sockets and pivot apertures are arranged so that either blade may be fitted to either of the handle members.

4. An implement as claimed in Claims 1 or 2, wherein the sockets and pivot apertures are arranged so that only a particular one of said blades can be fitted to a particular one of said handle members.

5. An implement as claimed in Claims 1,2,3 or 4, wherein the sockets and pivot apertures are arranged so that each blade can only be fitted in a predetermined orientation relative to the respective handle member.

6. An implement as claimed in any preceding claim, wherein each socket is formed as an aperture extending through the blade, and each protuberance is formed as an integral part of the handle member.

7. A cutting implement substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 of the accompanying drawings.

8. A combination comprising a cutting implement as claimed in any preceding claim and one or more sets of spare or alternative forms of blade, in which each blade incorporates a plurality of said sockets and a said pivot aperture.