Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
  • B27B33/00—Sawing tools for saw mills, sawing machines, or sawing devices
  • B27B33/14—Saw chains
  • B27B33/142—Cutter elements
  • B27B33/145—Cutter elements having plural teeth on a single link
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
  • B27B17/00—Chain saws; Equipment therefor
  • B27B17/0083—Attachments for guiding or supporting chain saws during operation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
  • B27B17/00—Chain saws; Equipment therefor
  • B27B17/02—Chain saws equipped with guide bar
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
  • B27B17/00—Chain saws; Equipment therefor
  • B27B17/08—Drives or gearings; Devices for swivelling or tilting the chain saw
  • B27B17/086—Angle drives

Definitions

• the present invention relates generally to a tool for non-sparking cutting of metal, such as motor-car metal sheeting, and more particularly to a hand tool which is useful especially in life-saving service.
• German Patent 807,578 disloses a hand tool having a plate-shaped metal saw blade.
• the tool is driven by an electric motor provided with a reduction gear so as to rotate the saw blade at 60-150 rpm.
• the invention describ ⁇ ed in this patent is intended to facilitate, for example, the cutting of sectional elements and massive workpieces that were previously cut manually.
• the low speed of rota ⁇ tion of the saw blade implies that a cut is produced which does not require finishing.
• This tool is unsuitable as a rescue tool, even if the low speed of rotation of the saw blade, in case the tool is all the same used as a rescue tool, renders it possible to cut e.g. metal sheet without sparks being formed. Since the cutting depth of the known tool is very limited, and a different cutting blade of a greater diameter cannot be mounted on the tool without difficulties, the tool is most unsuitable as a rescue tool, when it is a matter of cutting e.g. the metal sheeting of a car and a beam located at a considerable depth in the car. Owing to the design of the prior art tool, it cannot in practice be used in narrow spaces.
• French Patent 2,159,813 discloses a very simple, but still effective device for cutting in the first place, for example, metal bars in spaces difficult of access.
• a special chain for sawing e.g. metal is laid around the position in which the cutting is to be performed.
• the free ends of the chain are attached either to handles or to a manual or motor-driven rocker.
• the cutting chain extends around the sawing position and by intermittent motion, either manual or motor-driven, the chain effects the cut ⁇ ting of material.
• the free ends of the cutting chain are connected to each other so as to provide an endless cutting chain which is driven by a driving means.
• the chain must, however, still be laid around the cutting position. Consequently it is impossible to cut by means of this saw e.g. the metal sheeting of a car to rescue a person locked up in the car and possibly injured.
• US Patent Specification 2,649,871 discloses a chain saw attachment for drills.
• This drill attachment is intended for use in, for example, firewood sawing and should replace or supplement existing chain saws.
• This attachment is extremely unsuitable as a professional rescue tool owing to its design and the inventive concept.
• US Patent Specification 3,693,676 discloses a chain saw for cutting off underwater pilings and the like. It comprises a circular cutting support which adjacent the bottom of the sea serves as an abutment when cutting off objects in the water. The field of application and the mode of operation of the chain saw, however, distinguish considerably from those of the present specification.
• US Patent Specification 2,708,953 discloses a chain saw for use in forestry, provided with a cutting support formed with teeth and mounted on a straight guide member. As appears from the specification below it is, however, impossible to use such a cutting support in the rescue tool according to the invention.
• German Patent Specification 495,132 discloses a chain saw having a guide bar which is pivotable about a point P. This chain saw is especially suitable for stationary positioning when cutting logs.
• the guide bar thus is pivotable in a plane defined by the guide bar.
• the torque of the motor is transmitted via a long drive shaft and an angular gear to the driving wheel of the cutting chain.
• German Patent Specification 656,811 dis ⁇ closes a chain saw having a guide bar arranged perpen ⁇ dicular to the feeding direction of the saw.
• One object of the present invention thus is to pro- vide a hand tool first of all for rescue operations, by means of which it is possible to cut, without risk of sparks being formed, metal, such as motorcar metal sheet and reinforcement beams, but also other metal objects where sparks could ignite inflammable fluids, such as highly inflammable gases.
• a second object of the present invention is to provide a tool having a great cutting depth, in which the cutting member can be angularly set in different planes for suitable use also in narrow spaces.
• a third object of the present invention is to design a rescue tool in such a manner that metal chips do not get into the object which is being cut.
• the tool should be possible to use in com ⁇ bination with different driving systems, such as hydrau- lie, pneumatic or electric driving systems, and the cutt ⁇ ing member should be easily replaceable when a greater cutting depth is required and for economic and convenient handling.
• a hand tool comprising an elongate body, a reduction gear mounted in said body, a guide bar around which a cutting chain runs, and transmission means for transmitting the output torque of said reduction gear to the cutting chain, said hand tool being characterised in that the guide bar is pivotable about an axis substantially parallel with the longitudinal axis of said body, that the guide bar extends in a plane parallel with the pivot axis, and that the guide bar is fixable in an optional position about said axis, while extending substantially perpendicular to the longitudinal direction of the body.
• the guide bar is a single plate-shaped member supporting elements which are U-shaped in cross-section and assembled to a chain. These elements have teeth arranged so that the teeth of consecutive elements form an unbroken sequence along the straight longitudinal sides of the guide bar.
• a cutting support is attached to the device and prevents it from being pulled into the object which is being cut. The device tending to be pulled into the object depends on a combination of the cutting direction and the driving direction of the cutting chain.
• the cutting chain according to the present invention comprises, along the edge of the guide bar facing away from the operator, teeth directed from the free end of the guide bar.
• the guide bar with the cutting chain is connected to a body of the device so as to be pivotable about an axis extending substantially perpendicular to the longitudinal axis of the body.
• Fig. 1 is a schematic side view of an embodiment of a hand tool according to the invention, a protective cover being removed for better clarity.
• Fig. 2 is a cross-sectional view of a guide bar according to the invention, taken along the line A-A in Fig. 1.
• Fig. 3 is a side view of cutting chain elements according to the invention.
• Fig. 4 is a cross-sectional view of a cutting chain element taken along the line B-B in Fig. 3.
• Fig. 5 is a top plan view of one embodiment of a cutting support according to the invention.
• Fig. 6 is a top plan view of a further embodiment of the cutting support according to the invention.
• Fig. 1 illustrates an embodiment of a hand tool according to the invention, comprising a substantially elongate body 2 in which a reduction gear 4 is mounted.
• the reduction gear has an input shaft 6 which via a coupl ⁇ ing member 6A can be connected to any type of driving means.
• the reduction gear 4 has such a ratio that its output shaft 8 has a speed of about 60 rpm.
• the speed of a cutt- ing member can, however, be higher or lower depending on the design of a transmission means, but this will be discussed further down in the specification.
• a displaceable handle 10 which permits balancing of the hand tool.
• a cooling and/or cutting fluid can be pumped by a pump to a nozzle via a flexible conduit which should be possible to direct, at least adjacent the nozzle, so that the cutting position is sprayed with the cooling and/or cutting fluid.
• a guide bar 12 which extends perpendicular to the longitudi ⁇ nal direction of the body 2.
• the guide bar 12 is pivotable about an axis substantially parallel with the longitudinal axis of the body and is positioned in a plane parallel with the pivot axis.
• the guide bar 12 is fixable in an optional position about said axis by means of a tightening nut.
• the front edge of the guide bar is substantially straight and extends preferably perpendicular to the longitudinal axis of the body.
• Fig. 2 which is a cross-sectional view of the guide bar illustrated in Fig. 1
• the guide bar 12 according to the invention comprises a single, massive plate-shaped member.
• the guide bar 12 supports a cutting chain 18 composed of chain elements 14 shown in Figs 3 and 4 and provided with integrated teeth 16.
• Each element 14 is substantially U-shaped in cross-section (cf. Fig. 4).
• a plurality of teeth 16 which are connected with each other to form a unit 20 and positioned closely adjacent each other form the web, while legs 22, 24 connected to the unit 20 straddle the edge of the guide bar, the legs 22, 24 being designed to engage a sprocket 26 arranged on the guide bar.
• the sprocket is in turn connected to a bevel gear which allows the guide bar to pivot about an axis substantially parallel with the longitudinal axis of the body.
• the guide bar 12 is formed with an elongate slot 30 extending in the longitudinal direction of the guide bar.
• a cutting support 32 serving as an abutment is movably arranged in this slot.
• FIG. 5 shows a cutting support 32A according to the invention, having a centre slot 34 of such dimensions that the guide bar 12 can pass therethrough.
• Springs 40, 42 are arranged together with bearings 36, 38 mounted at the longitudinal sides of the slot, substantially in the central portion of the cutting support 32A and facing one another.
• a mounting bolt is inserted through the first spring 40 shaped as a coil spring, passes the first bearing 36, the slot 30, the second bearing 38 and the second spring 42 which is also shaped as a coil spring, and is secured in this position by means of e.g. a wing nut which is screwed onto a threaded end of the bolt.
• Fig. 6 illustates another cutting support 32B accord ⁇ ing to the invention, the construction details and func ⁇ tion of which essentially correspond to those described with reference to Fig. 5, and therefore the details will not be described once more.
• the cutting support 32B does not fully enclose the guide bar, but is formed with an open slot 46. To achieve the intended technical effect, the cutting support should, however, substantially enclose the guide bar 12.
• the output shaft 8 of the reduction gear is connected to the bevel gear via a coupling member 48, which in turn is connected to a coupling handle, and a universal joint 50.
• the guide bar is movable about an axis extending substantially perpendicular to the longi ⁇ tudinal axis of the body 2, thereby allowing minor changes of the cutting direction.
• a suitable driving means (not shown) is connected to the coupling member 6A of the input shaft 6 of the reduction gear 4. After starting the driving means, the torque of the reduction gear 4 is transmitted to the sprocket 26.
• this function also consti ⁇ tutes a most important safeguard, viz. a so-called dead man's handle. If the device according to the invention should be pulled away from the operator's hands and he lets go of the coupling handle, or if he gets hurt and loosens his grip on the coupling handle, the cutting chain 18 will stop immediately.
• the cutting chain 18 begins to move in a direction which in Fig. 1 is indicated by arrow P.
• the device is applied to the surface to be cut, for example a crashed car, whereby the cutting chain immediately starts to cut through the material.
• a slit has been cut in the material, which is of such a length that the guide bar can be put through to the cutting support 32, the actual cutt ⁇ ing operation begins.
• the operator pushes the device for- ward in a direction which in Fig. 1 is indicated by arrow F.
• the cutting chain cuts through the material from below and upwards, and the entire device tends to be pulled into the object that is being cut. This is prevented by the cutting support 32 which moreover follows the irregularities of the object that is being cut, as described above.
• the cutting position can be sprayed with cooling and/or cutting fluid which is pumped by the pump to the nozzle.
• the pump is suitably mounted on the output shaft 8 of the reduction gear 4.
• a closing means in the form of a throttle valve is mounted between the pump and the nozzle.
• the average expert of course realises that there may be other ways of transmitting the torque of the reduction gear to the drive shaft. For example, it would be possi ⁇ ble to use pulleys and a driving belt travelling around the pulleys. Moreover, a worm gear or the like could be used in stead of the angular gear, which serves the desired purpose. It will also be appreciated that the device according to the invention is useful not only as a rescue tool, but it can be used in many other fields where non-sparking cutting of metal is desired.
• the device according to the invention permits non-sparking cutting of metal also at great depths and in narrow spaces.
• the device according to the invention is com- paratively light and also very compact and well-balanced, which permits a functional and safe handling of the device in a rescue operation.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Sawing (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=20375435

Family Applications (1)

Country Status (3)

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Family Cites Families (8)

• 1989
  • 1989-03-23 SE SE8901038A patent/SE8901038L/ not_active Application Discontinuation
• 1990
  • 1990-09-24 WO PCT/SE1990/000608 patent/WO1992005003A1/en not_active Application Discontinuation
  • 1990-09-24 EP EP19900916390 patent/EP0550433A1/de not_active Withdrawn

Non-Patent Citations (1)

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