WO2019239008A1 - Hand operated shearing tool - Google Patents

Hand operated shearing tool Download PDF

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Publication number
WO2019239008A1
WO2019239008A1 PCT/FI2019/050443 FI2019050443W WO2019239008A1 WO 2019239008 A1 WO2019239008 A1 WO 2019239008A1 FI 2019050443 W FI2019050443 W FI 2019050443W WO 2019239008 A1 WO2019239008 A1 WO 2019239008A1
Authority
WO
WIPO (PCT)
Prior art keywords
blade
hole
handle
pin
shearing tool
Prior art date
Application number
PCT/FI2019/050443
Other languages
French (fr)
Inventor
Olavi Lindén
Original Assignee
Tmi Lindén Instruments
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tmi Lindén Instruments filed Critical Tmi Lindén Instruments
Publication of WO2019239008A1 publication Critical patent/WO2019239008A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26B—HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR
    • B26B13/00—Hand shears; Scissors
    • B26B13/28—Joints
    • B26B13/285—Joints with means for applying pressure on the blades; with means for producing "drawing-cut" effect
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G3/00—Cutting implements specially adapted for horticultural purposes; Delimbing standing trees
    • A01G3/02—Secateurs; Flower or fruit shears
    • A01G3/021—Secateurs; Flower or fruit shears characterized by the arrangement of pivots

Definitions

  • the present disclosure relates to shearing tools, and particularly to hand operated shearing tools, such as scissors.
  • the cutting capacity of traditional scissors intended for cutting fabric, leather etc. is limited by the force keeping the blades together. When this force is not high enough, the blades are forced apart and the material to be cut will be squeezed between the blades. If the blades are rigid enough and the geometry of the insides of the blades allows, this can be overcome by tightening the blades against each other at the pivot to allow a high cutting capacity, but then the“idle” cutting force will be great and the scissors awkward to use.
  • rolling elements e.g. balls resting in recesses in the coupling parts
  • the coupling between a blade and its handle comprises balls resting partly in recesses formed in a plate secured to the handle and partly in recesses formed in the blade, relative movement of the handles causing the balls to ride partially out of the recesses and thereby generate a force in a direction normal to the direction of the relative movement to bias the blades towards one another.
  • a blade is rigid with a handle and carries a pivot on which the blade is pivoted. The blade is movable relative to the blade by a coupling comprising balls nesting in frusto-conical recesses in a plate and in the upper face of the blade, the plate having a shoulder engageable by a finger on a plate carried by a movable handle pivoted to the handle.
  • An object of the present disclosure is to provide a shearing tool so as to provide an alternative way to improve the cutting capacity of a shearing tool.
  • a shearing tool which is characterized by what is stated in the independent claim.
  • the preferred embodiments of the disclosure are disclosed in the dependent claims.
  • the disclosure is based on the idea of providing a hand operated shearing tool, comprising a first unit comprising a first blade and a first handle fixed to the first blade at a proximal end of the first blade, the first blade comprising a first cutting edge; and a second unit comprising a second blade and a second handle connected to the second blade at a proximal end of the second blade, the second blade comprising a second cutting edge.
  • the second unit is connected rotatably to the first unit by a pivot.
  • the second handle is connected to the second blade by the pivot so that rotational movement of the second handle in relation to the second blade is allowed.
  • the second blade comprises a first hole arranged at the proximal end of the second blade.
  • the second handle comprises a second hole.
  • the second unit comprises a pin comprising a body and a head attached to an end of the body. The pin is arranged in the first hole and the second hole so that the body penetrates the first hole, a part of the body is in the second hole and the head is between the first blade and the second blade.
  • the first hole is arranged to allow tilting of the pin in relation to the second blade.
  • the second hole is arranged to allow tilting of the pin in relation to the second handle.
  • the second handle and the second blade are arranged to exert a tilting force to the pin due to a shearing force between the second handle and the second blade.
  • the head is arranged to exert a separating force to the proximal end of the first blade and the proximal end of the second blade driving the proximal end of the first blade and the proximal end of the second blade away from each other.
  • the first blade and the second blade by acting as levers and by using the pivot as a fulcrum, are arranged to exert a compressive force driving the first blade and the second blade towards each other at the opposite side of the pivot for increasing the cutting capacity of the shearing tool.
  • An advantage of the shearing tool of the disclosure is that its structure is simple requiring only a few parts, resulting in easier manufacturing. It is also a more efficient way to increase the cutting capacity of a shearing tool.
  • Figure 1 a is a schematic cross-sectional view of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state
  • Figure 1 b is a schematic cross-sectional view of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle;
  • Figure 2a is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state;
  • Figure 2b is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle;
  • Figure 3 is an explosion view of a hand operated shearing tool according to an embodiment of the disclosure.
  • Figure 4a is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state;
  • Figure 4b is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle;
  • Figure 5 is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state.
  • the disclosure relates to a hand operated shearing tool.
  • the hand operated shearing tool is a pair for scissors or a pair of shears, such as a pair of fabric scissors or sewing scissors, grass shears, hedge shears or plate shears.
  • the hand operated shearing tool comprises a first unit 1 .
  • the first unit 1 comprises a first blade 1 1 and a first handle 12 fixed to the first blade 1 1 at a proximal end 1 1 1 of the first blade 1 1 .
  • the first blade 1 1 comprises a first cutting edge 1 12.
  • the hand operated shearing tool comprises a second unit 2.
  • the second unit 2 comprises a second blade 21 and a second handle 22 connected to the second blade 21 at a proximal end 21 1 of the second blade 21 .
  • the second blade 21 comprises a second cutting edge 212.
  • the second unit 2 is connected rotatably to the first unit 1 by a pivot 3 defining a rotational axis R.
  • the pivot 3 is arranged to prevent the displacement of the first blade 1 1 in relation to the second blade 21 in a direction parallel with the rotational axis R and away from the second blade 21 .
  • the pivot 3 prevents moving the first blade 1 1 and the second blade 21 away from each other at the location of the pivot 3.
  • the pivot 3 is formed by a screw and a nut.
  • the second unit 2 is arranged to be rotated in relation to the first unit 1 about the rotational axis R between an open position of the shearing tool and a closed position of the shearing tool.
  • first cutting edge 1 12 and the second cutting edge 212 are in an angle of at least 45°.
  • first blade 1 1 and the second blade 21 are essentially parallel.
  • the second handle 22 is arranged to overlap with the second blade 21 at least partially.
  • At least one of the first blade 1 1 and the second blade 21 is curved and the first blade 1 1 and the second blade 21 are biased against each other so that the first cutting edge 1 12 and the second cutting edge 212 are in constant contact at a cutting edge contact point P when the hand operated shearing tool is moved between the open position and the closed position.
  • the object to be cut is cut at the cutting edge contact point P.
  • the cutting edge contact point P moves along the first cutting edge 1 12 and the second cutting edge 212.
  • the first blade 1 1 and the second blade 21 exert a cutting edge force towards each other at the cutting edge contact point P.
  • the cutting capacity of the shearing tool is directly proportional to the cutting edge force.
  • the proximal end 1 1 1 of the first blade 1 1 is located on one side of the pivot 3 away from the cutting edge contact point P.
  • the proximal end 21 1 of the second blade 21 is located on one side of the pivot 3 away from the cutting edge contact point P.
  • the second handle 22 is connected to the second blade 21 by the pivot 3 so that rotational movement of the second handle 22 in relation to the second blade 21 about the rotational axis R is allowed.
  • the second blade 21 comprises a first hole 213 arranged at the proximal end 21 1 of the second blade 21 .
  • the first hole 213 is a through hole.
  • the second handle 22 comprises a second hole 221 .
  • the second hole 221 can be a through hole or a blind hole.
  • the second hole 221 is aligned with the first hole 213 when no shearing force exists between the second handle 22 and the second blade 21 .
  • the second unit 2 comprises a pin 23.
  • the pin 23 comprises a body 231 and a head 232 attached to an end of the body 231 .
  • the body 231 is cylindrical and has a circular cross-section.
  • the body 231 has a uniform diameter along its length.
  • the head 232 is cylindrical and has a circular cross-section.
  • the body 231 and/or the head 232 can also have another shape.
  • the diameter of the head 232 is greater than the diameter of the first hole 213 for preventing the head 232 from penetrating the first hole 213.
  • the head has a diameter of 8 mm.
  • the pin 23 can be made of metal or plastic.
  • the pin 23 is arranged in the first hole 213 and the second hole 221 so that the body 231 penetrates the first hole 213, a part of the body 231 is in the second hole 221 and the head 232 is between the first blade 1 1 and the second blade 21 .
  • the head 232 is parallel with the second blade 21 , i.e. the plane of the head 232 is parallel with the second blade 21 .
  • the first hole 213 is arranged to allow tilting of the pin 23 in relation to the second blade 21 .
  • the diameter of the first hole 213 is such that tilting of the pin 23 is allowed, i.e. the diameter of the first hole 213 is slightly greater than the diameter of the body 231 .
  • the diameter of the first hole 213 increases towards the first blade 1 1 for facilitating tilting of the pin 23.
  • the second hole 221 is arranged to allow tilting of the pin 23 in relation to the second handle 22.
  • the diameter of the second hole 221 is such that tilting of the pin 23 is allowed, i.e. the diameter of the second hole 221 is at least partially greater than the diameter of the body 231 .
  • the diameter of the second hole 221 increases towards the second blade 21 for facilitating tilting of the pin 23 in relation to the second handle 22.
  • the diameter of the second hole 221 at a location away from the second blade 21 corresponds to the diameter of the end of the body 231 . This reduces slack from the movement of the second handle 22 in relation to the second blade 21 .
  • the diameter of the second hole 221 increases towards the second blade 21 at an angle a of 3 to 4° in relation to the axial direction of the second hole 221 .
  • the angle a of the increase of the diameter of the second hole 221 defines the maximum tilting angle of the pin 23.
  • the diameter of the second hole 221 increases only in the direction where the pin 23 needs to be tilted.
  • the second hole 221 may be asymmetric. This has been illustrated in Figures 2a and 2b.
  • the diameter of the body 231 decreases towards the head 232, preferably at an angle of 3 to 4° in relation to the axial direction of the second hole 221 and the second hole 221 has a uniform diameter for facilitating tilting of the pin 23 in relation to the second handle 22.
  • the diameter of the body 231 decreases only in the direction where the pin 23 needs to be tilted. In other words, the body 231 may be asymmetric.
  • the second handle 22 and the second blade 21 are arranged to exert a tilting force to the pin 23 due to a shearing force Fi between the second handle 22 and the second blade 21 when the shearing tool is moved from the open position towards the closed position.
  • a shearing force Fi is caused between the second handle 22 and the second blade 21 .
  • This shearing force Fi causes a force to the pin 23 that tries to tilt the pin 23, i.e. a tilting force.
  • the head 232 is arranged to exert a separating force F 2 to the proximal end 1 1 1 of the first blade 1 1 and the proximal end 21 1 of the second blade 21 driving the proximal end 1 1 1 of the first blade 1 1 and the proximal end 21 1 of the second blade 21 away from each other.
  • the tilting pin 23 acts as a lever prying the first blade 1 1 away from the second blade 21 so that one part of the head 232 contacts the first blade 1 1 at the proximal end 1 1 1 of the first blade 1 1 and another part of the head 232 contacts the second blade 21 at the rim of the first hole 213.
  • the first blade 1 1 and the second blade 21 are arranged to exert a compressive force F 3 driving the first blade 1 1 and the second blade 21 towards each other at the cutting edge contact point P, i.e. at the opposite side of the pivot 3, for increasing the cutting capacity of the shearing tool.
  • the first blade 1 1 and the second blade 21 act as levers using the pivot 3 as a fulcrum. This is enabled by the fact that the pivot 3 prevents moving the first blade 1 1 and the second blade 21 away from each other at the location of the pivot 3.
  • the compressive force F 3 the cutting edge force is increased. This in turn increases the cutting capacity of the shearing tool by reducing such a bending of the blades 1 1 , 21 where the cutting edges 1 12, 212 are separated from each other by the object to be cut.
  • the second blade 21 comprises a recess 214 for accommodating the head 232 at least partially.
  • the recess 214 reduces the wear of the pin 23 due to abrasion against the first blade 1 1 , especially if the pin 23 is made of plastic.
  • This embodiment is illustrated in Figures 1 a, 1 b, 2a, 2b, 4a and 4b.
  • the second blade 21 can also be realized without the recess 214, which is sufficient for example, when the pin 23 is made of metal. This embodiment is illustrated in Figure 5.
  • the second hole 221 is a blind hole
  • the second unit 2 comprises a spring 24 arranged in the second hole 221 between the pin 23 and the second handle 22 for biasing the pin 23 against the first blade 1 1 .
  • the spring 24 ensures that the pin 23 is always in contact with the first blade 1 1 .
  • this embodiment allows using a loose compression between the first unit 1 and the second unit 2 at the pivot 3. This reduces friction between the first unit 1 and the second unit 2, and thus makes using the shearing tool lighter. This would not be possible with traditional scissors, for example, because the cutting capacity is directly proportional to the compression between the units at the pivot.
  • This embodiment is illustrated in Figures 4a and 4b.

Abstract

The disclosure relates to a hand operated shearing tool, comprising a first unit (1) comprising a first blade (11) and a first handle (12) fixed to the first blade (11) at a proximal end (111) of the first blade (11), the first blade (11) comprising a first cutting edge (112); and a second unit (2) comprising a second blade (21) and a second handle (22) connected to the second blade (21) at a proximal end (211) of the second blade (21), the second blade (21) comprising a second cutting edge (212), wherein the second unit (2) is connected rotatably to the first unit (1) by a pivot (3); the second handle (22) is connected to the second blade (21) by the pivot (3) so that rotational movement of the second handle (22) in relation to the second blade (21) is allowed; the second blade (21) comprises a first hole (213) arranged at the proximal end (211) of the second blade (21); the second handle (22) comprises a second hole (221); the second unit (2) comprises a pin (23) comprising a body (231) and a head (232) attached to an end of the body (231); the pin (23) is arranged in the first hole (213) and the second hole (221) so that the body (231) penetrates the first hole (213), a part of the body (231) is in the second hole (221) and the head (232) is between the first blade (11) and the second blade (21); the first hole (213) is arranged to allow tilting of the pin (23) in relation to the second blade (21); the second hole (221) is arranged to allow tilting of the pin (23) in relation to the second handle (22); the second handle (22) and the second blade (21) are arranged to exert a tilting force to the pin (23) due to a shearing force (F) between the second handle (22) and the second blade (21); as a result of the tilting force, the head (232) is arranged to exert a separating force (F2) to the proximal end (111) of the first blade (11) and the proximal end (211) of the second blade (21) driving the proximal end (111) of the first blade (11) and the proximal end (211) of the second blade (21) away from each other; and as a result of the separating force (F2), the first blade (11) and the second blade (21) are arranged to exert a compressive force (F3) driving the first blade (11) and the second blade (21) towards each other at the opposite side of the pivot (3) for increasing the cutting capacity of the shearing tool.

Description

HAND OPERATED SHEARING TOOL
FIELD OF THE DISCLOSURE
The present disclosure relates to shearing tools, and particularly to hand operated shearing tools, such as scissors.
BACKGROUND OF THE DISCLOSURE
The cutting capacity of traditional scissors intended for cutting fabric, leather etc. is limited by the force keeping the blades together. When this force is not high enough, the blades are forced apart and the material to be cut will be squeezed between the blades. If the blades are rigid enough and the geometry of the insides of the blades allows, this can be overcome by tightening the blades against each other at the pivot to allow a high cutting capacity, but then the“idle” cutting force will be great and the scissors awkward to use.
Document US 3460251 A discloses a hand tool such as a pair of shears comprises a pair of pivotally-connected blades, a first handle rigid with a first blade and a second handle connected to a second blade through a coupling comprising rolling elements, e.g. balls resting in recesses in the coupling parts, the coupling being effective, when the tool is cutting or shearing a piece of material, to bias the blades towards one another in a direction perpendicular to the direction of their relative movement with a force which is related to the resistance offered by the material. In one embodiment, the coupling between a blade and its handle, comprises balls resting partly in recesses formed in a plate secured to the handle and partly in recesses formed in the blade, relative movement of the handles causing the balls to ride partially out of the recesses and thereby generate a force in a direction normal to the direction of the relative movement to bias the blades towards one another. In another embodiment, a blade is rigid with a handle and carries a pivot on which the blade is pivoted. The blade is movable relative to the blade by a coupling comprising balls nesting in frusto-conical recesses in a plate and in the upper face of the blade, the plate having a shoulder engageable by a finger on a plate carried by a movable handle pivoted to the handle.
BRIEF DESCRIPTION OF THE DISCLOSURE
An object of the present disclosure is to provide a shearing tool so as to provide an alternative way to improve the cutting capacity of a shearing tool.
The object of the disclosure is achieved by a shearing tool which is characterized by what is stated in the independent claim. The preferred embodiments of the disclosure are disclosed in the dependent claims. The disclosure is based on the idea of providing a hand operated shearing tool, comprising a first unit comprising a first blade and a first handle fixed to the first blade at a proximal end of the first blade, the first blade comprising a first cutting edge; and a second unit comprising a second blade and a second handle connected to the second blade at a proximal end of the second blade, the second blade comprising a second cutting edge. The second unit is connected rotatably to the first unit by a pivot. The second handle is connected to the second blade by the pivot so that rotational movement of the second handle in relation to the second blade is allowed. The second blade comprises a first hole arranged at the proximal end of the second blade. The second handle comprises a second hole. The second unit comprises a pin comprising a body and a head attached to an end of the body. The pin is arranged in the first hole and the second hole so that the body penetrates the first hole, a part of the body is in the second hole and the head is between the first blade and the second blade. The first hole is arranged to allow tilting of the pin in relation to the second blade. The second hole is arranged to allow tilting of the pin in relation to the second handle. The second handle and the second blade are arranged to exert a tilting force to the pin due to a shearing force between the second handle and the second blade. As a result of the tilting force, the head is arranged to exert a separating force to the proximal end of the first blade and the proximal end of the second blade driving the proximal end of the first blade and the proximal end of the second blade away from each other. As a result of the separating force, the first blade and the second blade, by acting as levers and by using the pivot as a fulcrum, are arranged to exert a compressive force driving the first blade and the second blade towards each other at the opposite side of the pivot for increasing the cutting capacity of the shearing tool.
An advantage of the shearing tool of the disclosure is that its structure is simple requiring only a few parts, resulting in easier manufacturing. It is also a more efficient way to increase the cutting capacity of a shearing tool.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which
Figure 1 a is a schematic cross-sectional view of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state;
Figure 1 b is a schematic cross-sectional view of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle; Figure 2a is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state;
Figure 2b is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle;
Figure 3 is an explosion view of a hand operated shearing tool according to an embodiment of the disclosure;
Figure 4a is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state;
Figure 4b is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a state where there is a shearing force between the second blade and the second handle; and
Figure 5 is a schematic cross-sectional view of a part of a hand operated shearing tool according to an embodiment of the disclosure in a relaxed state.
DETAILED DESCRIPTION OF THE DISCLOSURE
The disclosure relates to a hand operated shearing tool. For example, the hand operated shearing tool is a pair for scissors or a pair of shears, such as a pair of fabric scissors or sewing scissors, grass shears, hedge shears or plate shears.
The hand operated shearing tool comprises a first unit 1 . The first unit 1 comprises a first blade 1 1 and a first handle 12 fixed to the first blade 1 1 at a proximal end 1 1 1 of the first blade 1 1 . The first blade 1 1 comprises a first cutting edge 1 12.
The hand operated shearing tool comprises a second unit 2. The second unit 2 comprises a second blade 21 and a second handle 22 connected to the second blade 21 at a proximal end 21 1 of the second blade 21 . The second blade 21 comprises a second cutting edge 212.
The second unit 2 is connected rotatably to the first unit 1 by a pivot 3 defining a rotational axis R. The pivot 3 is arranged to prevent the displacement of the first blade 1 1 in relation to the second blade 21 in a direction parallel with the rotational axis R and away from the second blade 21 . In other words, the pivot 3 prevents moving the first blade 1 1 and the second blade 21 away from each other at the location of the pivot 3. For example, the pivot 3 is formed by a screw and a nut. The second unit 2 is arranged to be rotated in relation to the first unit 1 about the rotational axis R between an open position of the shearing tool and a closed position of the shearing tool. In the open position, the first cutting edge 1 12 and the second cutting edge 212 are in an angle of at least 45°. In the closed position, the first blade 1 1 and the second blade 21 are essentially parallel. Preferably the second handle 22 is arranged to overlap with the second blade 21 at least partially.
At least one of the first blade 1 1 and the second blade 21 is curved and the first blade 1 1 and the second blade 21 are biased against each other so that the first cutting edge 1 12 and the second cutting edge 212 are in constant contact at a cutting edge contact point P when the hand operated shearing tool is moved between the open position and the closed position. The object to be cut is cut at the cutting edge contact point P. As the hand operated shearing tool is moved from the open position to the closed position, the cutting edge contact point P moves along the first cutting edge 1 12 and the second cutting edge 212. The first blade 1 1 and the second blade 21 exert a cutting edge force towards each other at the cutting edge contact point P. The cutting capacity of the shearing tool is directly proportional to the cutting edge force.
The proximal end 1 1 1 of the first blade 1 1 is located on one side of the pivot 3 away from the cutting edge contact point P. The proximal end 21 1 of the second blade 21 is located on one side of the pivot 3 away from the cutting edge contact point P.
The second handle 22 is connected to the second blade 21 by the pivot 3 so that rotational movement of the second handle 22 in relation to the second blade 21 about the rotational axis R is allowed.
The second blade 21 comprises a first hole 213 arranged at the proximal end 21 1 of the second blade 21 . The first hole 213 is a through hole.
The second handle 22 comprises a second hole 221 . The second hole 221 can be a through hole or a blind hole. The second hole 221 is aligned with the first hole 213 when no shearing force exists between the second handle 22 and the second blade 21 .
The second unit 2 comprises a pin 23. The pin 23 comprises a body 231 and a head 232 attached to an end of the body 231 . Preferably, the body 231 is cylindrical and has a circular cross-section. In other words, the body 231 has a uniform diameter along its length. Preferably, the head 232 is cylindrical and has a circular cross-section. The body 231 and/or the head 232 can also have another shape. The diameter of the head 232 is greater than the diameter of the first hole 213 for preventing the head 232 from penetrating the first hole 213. For example, the head has a diameter of 8 mm. The pin 23 can be made of metal or plastic.
The pin 23 is arranged in the first hole 213 and the second hole 221 so that the body 231 penetrates the first hole 213, a part of the body 231 is in the second hole 221 and the head 232 is between the first blade 1 1 and the second blade 21 . Preferably, the head 232 is parallel with the second blade 21 , i.e. the plane of the head 232 is parallel with the second blade 21 .
The first hole 213 is arranged to allow tilting of the pin 23 in relation to the second blade 21 . In other words, the diameter of the first hole 213 is such that tilting of the pin 23 is allowed, i.e. the diameter of the first hole 213 is slightly greater than the diameter of the body 231 . According to an embodiment, the diameter of the first hole 213 increases towards the first blade 1 1 for facilitating tilting of the pin 23.
The second hole 221 is arranged to allow tilting of the pin 23 in relation to the second handle 22. In other words, the diameter of the second hole 221 is such that tilting of the pin 23 is allowed, i.e. the diameter of the second hole 221 is at least partially greater than the diameter of the body 231 . According to an embodiment, the diameter of the second hole 221 increases towards the second blade 21 for facilitating tilting of the pin 23 in relation to the second handle 22. Preferably, the diameter of the second hole 221 at a location away from the second blade 21 corresponds to the diameter of the end of the body 231 . This reduces slack from the movement of the second handle 22 in relation to the second blade 21 . According to an embodiment, the diameter of the second hole 221 increases towards the second blade 21 at an angle a of 3 to 4° in relation to the axial direction of the second hole 221 . The angle a of the increase of the diameter of the second hole 221 defines the maximum tilting angle of the pin 23. Preferably, the diameter of the second hole 221 increases only in the direction where the pin 23 needs to be tilted. In other words, the second hole 221 may be asymmetric. This has been illustrated in Figures 2a and 2b. According to an alternative embodiment, the diameter of the body 231 decreases towards the head 232, preferably at an angle of 3 to 4° in relation to the axial direction of the second hole 221 and the second hole 221 has a uniform diameter for facilitating tilting of the pin 23 in relation to the second handle 22. Preferably, the diameter of the body 231 decreases only in the direction where the pin 23 needs to be tilted. In other words, the body 231 may be asymmetric.
The second handle 22 and the second blade 21 are arranged to exert a tilting force to the pin 23 due to a shearing force Fi between the second handle 22 and the second blade 21 when the shearing tool is moved from the open position towards the closed position. In other words, when the shearing tool is moved from the open position to the closed position and a resistance caused by the object to be cut is encountered, a shearing force Fi is caused between the second handle 22 and the second blade 21 . This shearing force Fi causes a force to the pin 23 that tries to tilt the pin 23, i.e. a tilting force. As a result of the tilting force, the head 232 is arranged to exert a separating force F2 to the proximal end 1 1 1 of the first blade 1 1 and the proximal end 21 1 of the second blade 21 driving the proximal end 1 1 1 of the first blade 1 1 and the proximal end 21 1 of the second blade 21 away from each other. In other words, the tilting pin 23 acts as a lever prying the first blade 1 1 away from the second blade 21 so that one part of the head 232 contacts the first blade 1 1 at the proximal end 1 1 1 of the first blade 1 1 and another part of the head 232 contacts the second blade 21 at the rim of the first hole 213.
As a result of the separating force F2, the first blade 1 1 and the second blade 21 are arranged to exert a compressive force F3 driving the first blade 1 1 and the second blade 21 towards each other at the cutting edge contact point P, i.e. at the opposite side of the pivot 3, for increasing the cutting capacity of the shearing tool. In other words, the first blade 1 1 and the second blade 21 act as levers using the pivot 3 as a fulcrum. This is enabled by the fact that the pivot 3 prevents moving the first blade 1 1 and the second blade 21 away from each other at the location of the pivot 3. As a result of the compressive force F3, the cutting edge force is increased. This in turn increases the cutting capacity of the shearing tool by reducing such a bending of the blades 1 1 , 21 where the cutting edges 1 12, 212 are separated from each other by the object to be cut.
According to an embodiment, the second blade 21 comprises a recess 214 for accommodating the head 232 at least partially. The recess 214 reduces the wear of the pin 23 due to abrasion against the first blade 1 1 , especially if the pin 23 is made of plastic. This embodiment is illustrated in Figures 1 a, 1 b, 2a, 2b, 4a and 4b. The second blade 21 can also be realized without the recess 214, which is sufficient for example, when the pin 23 is made of metal. This embodiment is illustrated in Figure 5.
According to an embodiment, the second hole 221 is a blind hole, and the second unit 2 comprises a spring 24 arranged in the second hole 221 between the pin 23 and the second handle 22 for biasing the pin 23 against the first blade 1 1 . Because the spring 24 ensures that the pin 23 is always in contact with the first blade 1 1 , this embodiment allows using a loose compression between the first unit 1 and the second unit 2 at the pivot 3. This reduces friction between the first unit 1 and the second unit 2, and thus makes using the shearing tool lighter. This would not be possible with traditional scissors, for example, because the cutting capacity is directly proportional to the compression between the units at the pivot. This embodiment is illustrated in Figures 4a and 4b.

Claims

1. A hand operated shearing tool, comprising
- a first unit (1 ) comprising a first blade (1 1 ) and a first handle (12) fixed to the first blade (1 1 ) at a proximal end (1 1 1 ) of the first blade (1 1 ), the first blade (1 1) comprising a first cutting edge (1 12); and
- a second unit (2) comprising a second blade (21 ) and a second handle (22) connected to the second blade (21 ) at a proximal end (21 1 ) of the second blade (21 ), the second blade (21 ) comprising a second cutting edge (212),
wherein
the second unit (2) is connected rotatably to the first unit (1 ) by a pivot (3) defining a rotational axis (R), the pivot (3) being arranged to prevent the displacement of the first blade (1 1 ) in relation to the second blade (21 ) in a direction parallel with the rotational axis (R) and away from the second blade (21 );
the second unit (2) is arranged to be rotated in relation to the first unit (1 ) about the rotational axis (R) between an open position of the shearing tool and a closed position of the shearing tool; and
at least one of the first blade (1 1 ) and the second blade (21 ) is curved and the first blade (1 1 ) and the second blade (21 ) are biased against each other so that the first cutting edge (1 12) and the second cutting edge (212) are in constant contact at a cutting edge contact point (P) when the hand operated shearing tool is moved between the open position and the closed position,
characterized in that
the second handle (22) is connected to the second blade (21 ) by the pivot (3) so that rotational movement of the second handle (22) in relation to the second blade (21 ) about the rotational axis (R) is allowed;
the second blade (21 ) comprises a first hole (213) arranged at the proximal end (21 1 ) of the second blade (21 );
the second handle (22) comprises a second hole (221 ), the second hole (221 ) being aligned with the first hole (213) when no shearing force exists between the second handle (22) and the second blade (21 );
the second unit (2) comprises a pin (23) comprising a body (231 ) and a head (232) attached to an end of the body (231 ), wherein the diameter of the head (232) is greater than the diameter of the first hole (213); the pin (23) is arranged in the first hole (213) and the second hole (221 ) so that the body (231 ) penetrates the first hole (213), a part of the body (231 ) is in the second hole (221 ) and the head (232) is between the first blade (1 1 ) and the second blade (21 ) ;
the first hole (213) is arranged to allow tilting of the pin (23) in relation to the second blade (21 );
the second hole (221 ) is arranged to allow tilting of the pin (23) in relation to the second handle (22);
the second handle (22) and the second blade (21 ) are arranged to exert a tilting force to the pin (23) due to a shearing force (Fi) between the second handle (22) and the second blade (21 ) when the shearing tool is moved from the open position towards the closed position;
as a result of the tilting force, the head (232) is arranged to exert a separating force (F2) to the proximal end (1 1 1 ) of the first blade (1 1 ) and the proximal end (21 1 ) of the second blade (21 ) driving the proximal end (1 1 1 ) of the first blade (1 1 ) and the proximal end (21 1 ) of the second blade (21 ) away from each other; and
as a result of the separating force (F2), the first blade (1 1 ) and the second blade (21 ) are arranged to exert a compressive force (F3) driving the first blade (1 1 ) and the second blade (21 ) towards each other at the cutting edge contact point (P) for increasing the cutting capacity of the shearing tool.
2. A hand operated shearing tool according to claim 1 , characterized in that the second blade (21 ) comprises a recess (214) for accommodating the head (232) at least partially.
3. A hand operated shearing tool according to claim 1 or 2, characterized in that the diameter of the second hole (221 ) increases towards the second blade (21 ).
4. A hand operated shearing tool according to claim 3, characterized in that the diameter of the second hole (221 ) increases towards the second blade (21 ) at an angle of 3 to 4° in relation to the axial direction of the second hole (221 ).
5. A hand operated shearing tool according to any one of the preceding claims, characterized in that the diameter of the first hole (213) increases towards the first blade (1 1 ).
6. A hand operated shearing tool according to any one of the preceding claims, characterized in that the second hole (221 ) is a blind hole, and the second unit (2) comprises a spring (24) arranged in the second hole (221 ) between the pin (23) and the second handle (22) for biasing the pin (23) against the first blade (1 1 ).
PCT/FI2019/050443 2018-06-15 2019-06-07 Hand operated shearing tool WO2019239008A1 (en)

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FI20185542 2018-06-15
FI20185542A FI128058B (en) 2018-06-15 2018-06-15 Hand operated shearing tool

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210308883A1 (en) * 2018-07-27 2021-10-07 Fiskars Finland Oy Ab Hand operated shearing tool

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US805219A (en) * 1904-11-19 1905-11-21 Merrick A Mihills Tension device for shears.
US946918A (en) * 1909-08-20 1910-01-18 George H Isbell Scissors or shears.
US3460251A (en) * 1966-03-29 1969-08-12 Wilkinson Sword Ltd Shears,scissors and other handtools
DE4302921A1 (en) * 1993-02-03 1994-08-04 Ulrich Brabender Scissors with adjusting screw

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US805219A (en) * 1904-11-19 1905-11-21 Merrick A Mihills Tension device for shears.
US946918A (en) * 1909-08-20 1910-01-18 George H Isbell Scissors or shears.
US3460251A (en) * 1966-03-29 1969-08-12 Wilkinson Sword Ltd Shears,scissors and other handtools
DE4302921A1 (en) * 1993-02-03 1994-08-04 Ulrich Brabender Scissors with adjusting screw

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210308883A1 (en) * 2018-07-27 2021-10-07 Fiskars Finland Oy Ab Hand operated shearing tool
US11654585B2 (en) * 2018-07-27 2023-05-23 Fiskars Finland Oy Ab Hand operated shearing tool

Also Published As

Publication number Publication date
FI128058B (en) 2019-08-30
FI20185542A1 (en) 2019-08-30

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