GB2340428A

GB2340428A - Cutting device

Info

Publication number: GB2340428A
Application number: GB9817912A
Authority: GB
Inventors: Steve Wensley
Original assignee: Fiskars UK Ltd
Current assignee: Fiskars UK Ltd
Priority date: 1998-08-17
Filing date: 1998-08-17
Publication date: 2000-02-23
Also published as: GB9817912D0; DE19938385A1

Abstract

A shear-type cutting device has first and second handles 10, 11 that can be manually operated with a scissor action to open and close a pair of blades 12, 13. The blades move in a plane normal to the plane of movement of the handles. A gear system comprising bevel gears 37, 59 connects the scissor action into the blade movement. The handles are interconnected by a snap-fit pivot 36.

Description

2340428 CUTTING nEVTCR.

The invention relates to cutting devices of the kind comprising a pair of handles and a pair of blades. The handles are operated with a scissor action and this scissor action produces corresponding opening and closing movement of the blades. The plane of movement of the blades is normal to the plane of movement of the handles. Such devices can be used for cutting grass and other plants.

There have been many proposals for converting the scissor action into shearing movement of the blades. DE-A-1212342 shows a rod which is reciprocated by the scissor action with the reciprocation being converted into the shearing action of the blades. A similar proposal is the subject of EP-A-0215387 and DEU-A-G9413872.9.

All of these proposals have the problem that a significant number of parts are required in the construction of the shears. In addition, the use of a reciprocating rod is not always reliable since the rod can become deformed.

According to a first aspect of the invention, there is provided a cutting device comprising first and second handles 2 pivoted together for relative opening and closing movement, first and second blades pivoted together for performing a cutting action in a plane normal to the plane of the opening and closing movement of the handles and a geared drive transfer mechanism acting between the first and second handles, on the one hand, and the first and second blades, on the other hand, for converting opening and closing movement of the first and second handles into cutting action of the first and second blades.

According to a second aspect of the invention, there is provided a cutting device comprising first and second handles pivoted together for relative opening and closing movement and first and second blades pivoted together for performing a cutting action in a plane normal to the plane of the opening and closing of the movement of the handles, the first handle and the second handle including respective parts that snap-fit together to form a pivot therebetween.

The provision of a gear mechanism or a snap-fit scissor-action pivot allows the number of parts to be reduced significantly while providing satisfactory operation.

3 The following is a more detailed description of an embodiment of the invention, by way of example, reference being made to the accompanying drawings in which:-

Figure 1 is a side elevation of a single handed shear, internal components of the shear being shown in broken line, Figure 2 is a plan view of the shear of Figure 1 from above showing, in full line, blades of the shear closed together 10 and, in dotted line, a second blade of the shear in an open position, parts of a first handle of the shear being cut away to reveal an internal bevel gear, Figure 3 is a side elevation of the first handle of the shear of Figures 1 and 2 with internal parts being shown in broken line, Figure 4 is a plan view from above of the first handle of Figure 3, again with internal parts being shown in broken 20 line, Figure 5 is a side elevation of a second handle of the shear of Figures 1 to 4 with internal parts being shown in broken line, 4 Figure 6 is an underneath plan view of the second handle of Figure 5, Figure 7 is a side elevation of a catch of the shear of Figures 1 to 6, Figure 8 is a plan view from above of a second bevel gear for use in the shears of Figures 1 to 7, and Figure 9 is an underneath plan view of the bevel gear of Figure 8. Referring first to Figure 1, the shear comprises a first handle 10, a second handle 11, a first blade 12, and a second 15 blade 13. The first and second handles 10,11 are moulded from a plastics material and the first and second blades, 12,13 are made from a suitable steel. Referring next to Figure 2, the first handle comprises a body 20 portion 14 and a manually grippable portion 15. The body portion 14 has parallel side walls 16 with respective inner and outer side edges 17,18 (see Figure 1). A cover 19 extends between the outer side edges and, as best seen in Figure 4, a mounting plate 20 projects from the lower edge of the cover 19 25 and the lower edge of one of the side walls 16 within a space bounded by the side walls 16 and the cover 19. The mounting plate 20 lies in a plane normal to the planes of the side walls 16. The mounting plate 20 is provided with a fixing hole 21.

A pair of parallel mounts 22 also project from the cover 19 towards the lower end of the cover 19. Each mount 22 is in the form of a plate lying in a plane generally parallel to the planes of the side wall 16 and formed with an arcuate recess 23 which subtends more than 1800. The recesses 23 of the two mounts 22 are in register and lie on a common axis parallel to the plane of the mounting plate 20 spaced above the mounting plate 20 and normal to the planes of the side wall 16.

The outer surface of one side wall 16, the lower side wall 16 as seen in Figure 4, is formed with a catch recess 24. The catch recess 24 comprises a generally triangular depression 25 within which is a hole 26 having an axis parallel to the axis of the recesses 23, and an aperture 27 having a lower edge 28 generally parallel to an adjacent lower edge 29 of the depression 25. A rib 30 is provided on the portion of the depression between the lower edge 28 of the aperture 27 and the lower edge 29 of the depression 25. The length of the rib lies on a radius having its centre on the axis of the hole 26.

6 A peg 31 is provided at the upper end of the cover 19 and projects into the cavity for a purpose to be described below.

The manually grippable portion 15 is narrower than the body portion 14 and, as seen in Figures 3 and 4, projects upwardly and away f rom the body portion 14. The portion 15 has internal ribs 32 for strength.

The second handle 11 has a head 33 and a manually grippable portion 34. The head has parallel spaced side walls 35 lying in respective parallel planes. Two trunnions 36 are provided, each trunnion 36 projecting outwardly from an associated one of the side walls 35. The axis of the trunnions 36 are co axial and are normal to the planes of the side walls 35.

is The lower edge of one side wall is formed with an arcuate bevel gear 37. The gear 37 has an arcuate extent of about 901>. As seen in Figure 5, the gear 37 is disposed about a vertical plane including the axis of the trunnions 36. The teeth of the gear lie on respective lines that make an angle of about 450 with a vertical plane normal to the axis of the trunnions 36.

one of the second handle side walls 35, the lower side wall as seen in Figure 6, carries an abutment 38.The abutment 38 7 projects outwardly of the associated side wall 35 and is in the form of an arcuate rib about the axes of the trunnions 36.

The rib extends from an upper edge 39 of the associated side wall 35 and terminates between the upper edge 39 and an associated lower edge 40. The rib has an arcuate outer wall 41 and an inner wall 42 that is arcuate as it extends away from the upper edge 39 but then has increased curvature so that the thickness of the rib is wider at the end remote from the upper edge 39 than it is at the upper edge 39. At this remote end, the outer wall 41 and the inner wall 42 are connected by an end wall 43 with a projection 44 being provided between the end wall 43 and the outer wall 41. This abutment 38 co-operates with a catch that will be described below.

The second handle 11 is provided with strengthening ribs and these ribs carry a peg 46.

The manually grippable portion 34 extends arcuately away from the head 33 and is of generally U-shaped cross section.

The first and second blades 12,13 are best seen in Figure 2.

The first blade 12 has a cutting edge 47 and a back edge 48 meeting at a tip 49. The end of the first blade 12 opposite the tip 49 is generally rectangular with four mounting holes 8 (see Figure 2) The second blade 13 also has a cutting edge 51 and a back edge 52 with the edges meeting at a tip 53.

The end of the second blade 13 opposite the tip 53 is formed with a curved end edge 54. In the centre of the curved portion, there is a hole 55 that is generally rectangular but has a cut out (not shown) in one edge.

The parts described above fit together as follows.

The second handle 11 is connected to the first handle 10 by insertion of the trunnions 36 in the recesses 23 and the mounts 22. Since the recesses 23 have an arcuate extent of more than 18011, the trunnions 36 are a snapfit into the recesses 23. This mounts the second handle 11 on the first 15 handle 10 for pivotal movement about an axis co-axial with the axis of the trunnions 36 and the recesses 23. As the parts are assembled in this way, a spring 56 (see Figure 1) is engaged between the peg 31 on the first handle and the peg 46 on the second handle. The spring 56 acts to urge the second 20 handle 11 away from its closed position relative to the first handle 10 as shown in Figure 1. It will be appreciated that any suitable spring may be used. The f irst blade 12 is connected to the f irst handle 10 by 25 insert moulding with the material of the f irst handle 10 9 passing through holes 50 on the first blade 12. The end of the second blade 13 opposite the tip 53 is inserted through a slot 57 at the lower end of the cover 19 in the first handle (see Figure 3). In this position, it overlies the first blade 10. The second blade 13 is fixed to the mounting plate by a bolt 58 that extends through the fixing hole 21 in the mounting plate, through a central hole in the first blade 12 and through the hole 55 in the second blade 13. The bolt 58 also mounts a second bevel gear 59 on the second blade 13.

This bevel gear 59 is shown in more detail in Figures 8 and 9.

The second bevel gear 59 comprises a generally annular member with a frusto-conical outer surface 60 provided with bevel is teeth 61 with an annular extent of about 900. The centre of the second bevel gear is provided with a recess 62 that has the shape of a nut and is also provided with a central hole 63. The under surface of the second bevel gear 59 is provided with a boss 64 that has a complementary shape to the hole 55 in the second blade 13.

This boss 64 of the second bevel gear 59 is inserted into the hole 55 on the second blade 13 and the nut 65 of the bolt 58 is inserted into the recess 62. As the bolt 58 is tightened, the parts are held firmly together while allowing relative angular movement between the first and second blades 12, 13.

The engagement between the boss 64 on the second bevel gear 59 and the hole 55 on the second blade 13 ensures that these two parts are locked for rotation together. Alternatively, the second bevel gear 59 may be connected to the second blade 13 by insert moulding.

When so mounted, the second bevel gear 59 meshes with the bevel gear 37 on the second handle 11. The meshing is such that when the second handle 11 is in the closed position shown in Figure 1, the first and second blades 12, 13 are closed together also as shown in Figure 1. Thus, when the second handle 11 moves downwardly away from the first handle 10 under the action of the spring 56, the second handle 11 rotates about the trunnions 36 and the associated bevel gear 57 rotates the second bevel gear 59 so opening the second blade 13 relative to the first blade 12 to the open position shown in chain dotted line in Figure 2. The first blade 12 does not move relative to the first handle 10.

A catch, indicated generally at 66, is provided to lock the second handle 11 to the first handle 10 when the second handle 11 is in the closed position shown in Figure 1 - The catch comprises a catch member 67 best seen in Figure 7. The catch member 67 is moulded from a plastics material and comprises a 11 generally rectangular section body 68 having an outer face 69 formed with a rib 70 for engagement by a thumb of a user. The body 68 also has an inner face 71 provided at one end with a split mounting spigot 72. A peg 73 extends from the other end of the inner face 71 and is formed at its outer end with a head 74.

The catch member 67 is carried by the first handle 10 with the spigot 72 extending through and engaging the hole 26 associated with the catch recess 24. The peg 73 extends through the aperture 27 in the catch recess 24 with the head 74 engaging the inner surface of the associated side wall 16.

The spigot 72 mounts the catch member 67 for swinging movement is about the axis of the hole 26. During such movement, the head 74 slides along the adjacent side wall surface and the inner face 71 runs along the portion of the depression 25 between the extreme ends of the lower edge 28 of the aperture 27.

During this movement, the inner face 71 of the catch member 67 engages the rib 30 on the depression 25. Due to the inherent flexibility of the parts, the catch member 67 rides over this rib 30, but the rib 30 provides a resistance which can be felt so indicating that the catch 66 has been moved from one limiting position to the opposite limiting position.

12 The catch member 67 co-operates with the abutment 38 on the second handle 11. As seen in Figure 1, when the second handle 11 is in the closed position shown in Figure 1, the catch member 67 can be pushed "forward" (i.e. closer to the cover 19) and in this position the head 74 engages the end wall 43 of the abutment 38. This prevents the second handle 11 pivoting away from the first handle 10 under the action of the spring 56.

From this position, by pulling back on the rib 70, the catch member 67 can be swung about the spigot 72 away from the cover 19 with the rib 30 providing a tangible indication that such movement is taking place. This also prevents inadvertent release of the catch 66. At the same time, the head 74 rides over the projection 44 on the abutment 38 to close slightly the second handle 11 towards the first handle 10. The head 74 then disengages from the end wall 43 leaving the second handle 11 free to pivot. Reverse movement of the catch member 67, with the second handle 11 in the closed position of Figure 1, re-engages the head 74 with the end wall 43 of the abutment 38. If the catch member 67 is moved to this operative position with the second handle 11 open relative to the first handle 10, the abutment hits the outer wall 41 of the abutment and is inoperative.

The shear described above with reference to the drawings can be used for cutting grass or other plants. The catch is released and the first and second handles 10,11 gripped by a user's hand.

The first and second handles 10,11 are worked with a scissor action to open and close the first and second blades 12,13.

The blades 12,13 thus perform a cutting action in a plane normal to the plane of movement of the handles. After use, the first and second blades 12,13 are held closed by use of the catch 66.

It will be appreciated that the shear described above with reference to the drawings is simple in construction and thus is easy and inexpensive to manufacture. There are very f ew working parts (only nine different parts are described above with reference to the drawings) and this is a significantly smaller number of parts than previous proposals. A large reduction in the number of parts arises from the use of the gears and also from the use of the snap-fit scissor-action pivotal connection between the handles 10,11.

It will be appreciated that the gear drive between the second handle 11 and the second blade 13 need not be exactly as described above. Any suitable form of gear connection could 14 be provided. The catch 66 is optional, although for safety reasons it should generally be included. The second handle 11 need not be mounted on the first handle 10 exactly as described above. A bolt arrangement could be used. The first and second handles 10,11 need not be made from a plastics material; they could be made from metal.

In addition, although the drawings show a shear, the same principle could be applied to any cutting device where handles open and close in a plane normal to the plane of movement of the blades.

The gears need not be bevel gears, any suitable geared drive transfer mechanism may be used.

CLATMS 1. A cutting device comprising first and second handles pivoted together for relative opening and closing movement, first and second blades pivoted together for performing a cutting action in a plane normal to the plane of the opening and closing movement of the handles and a geared drive transfer mechanism acting between the first and second handles, on the one hand, and the first and second blades, on the other hand, for converting opening and closing movement of the first and second handles into cutting action of the first and second blades.

2. A cutting device comprising first and second handles is pivoted together for relative opening and closing movement and first and second blades pivoted together for performing a cutting action in a plane normal to the plane of the opening and closing of the movement of the handles, the first handle and the second handle including respective parts that snap-fit together to form a pivot therebetween.

3. A device according to claim 2 wherein a geared drive transfer mechanism acts between the first and second handles, on the one hand, and the first and second blades, on the other hand, for converting opening and closing movement of the first 16 and second handles into cutting action of the first and second blades.

4. A device according to any one of claims 1 to 3 wherein the first blade is fixed to the first handle with the second handle being pivoted on the first handle and the second blade pivoted on the first blade, the geared drive transfer mechanism acting between the second handle and the second blade.

5. A device according to any one of claims 1 to 4 wherein the geared drive transfer mechanism includes first and second meshing bevel gears.

6. A device according to claim 4 when dependent on claim 4 wherein the first bevel gear is carried by the second handle and the second bevel gear is carried by the second blade.

7. A device according to claim 6 wherein the first bevel gear has a gear axis co-axial with the pivotal axis of the second handle and the second bevel gear has a gear axis co axial with the pivotal axis of the second blade.

8. A device according to claim 7 wherein the second handle is pivoted on the f irst handle at a point between the ends 17 thereof, a portion of the handle to one side of the pivot point being manually grippable and the portion of the handle to the other side of the pivot point carrying said first bevel gear.

9. A device according to claim 8 wherein the first bevel gear is formed integrally with the second handle.

10. A device according to claim 8 wherein the first bevel gear is insert moulded to the second handle, the second handle being formed from a plastics material.

11. A shear according to any one of claims 7 to 10 wherein the first handle includes a plate which engages the first blade, the plate including a hole for receiving a part which pivotally mounts the second blade on the first blade, fixes the first blade to the first handle and fixes the second bevel gear to the second blade.

12. A device according to any one of claims 6 to 10 wherein the second bevel gear is insert moulded to the second blade.

13. A shear according to any one of claims 5 to 12 wherein at least one of the f irst and second bevel gears has an arcuate extent of less than 900.

18 14. A shear according to any one of claims 1 to 13 wherein a spring acts between the first and second handles, the spring tending to urge the first and second handles to said opening movement, the geared drive transfer mechanism converting said opening movement of the first and second handles into closing movement of the first and second blades.

is. A shear according to any one of claims 1 to 14 wherein a catch is provided for holding the first and second handles in a closed position.

16. A shear according to claim 15 wherein the catch includes a catch member carried on the first handle and manually movable between operative and inoperative positions, movement of the catch member to the operative position with the second handle closed relative to the first handle engaging the catch member with the second handle to hold the second handle closed, movement of the catch from said operative position to the inoperative position releasing the second handle for opening and closing movement.

17. A shear according to claim 16 wherein the second handle includes an abutment, movement of the catch member to the operative position, with the second handle closed, engaging 19 the catch member with the abutment to hold the second handle closed.

18. A shear according to claim 16 or claim 17 wherein, during movement of the catch member between the operative and the inoperative positions, the catch member engages with a resistance member to provide a positive indication that the catch member is moving from one position to the other.

19. A shear according to any one of claims 16 to 18 wherein the catch member pivots between the operative and the inoperative positions.

20. A device according to claim 2 or any claim appendant is thereto wherein the one handle includes two spaced mounting plates lying in respective planes normal to the pivot axes of the first and second handles, each mounting plate including a recess, the other handle including a pair of trunnions that are a snap-fit in respective recesses to form said pivot.

21. A device according to claim 20 wherein the first and second handles are moulded from a plastics material with the mounting plates being formed integrally with the first handle and the trunnions being formed integrally with the second handle.