ERGONOMIC CHAINSAW WITH HIGH OPERATION SAFETY

Abstract

A chainsaw which has a motorized chain that is suitable for sawing and trimming objects. The chainsaw includes a motor housing comprising a side portion, a chain, a guide bar, an electric motor, and a front handle. Safer handling and ergonomics is achieved by the motor housing comprising a concave contour on part of the surface of the side portion.

Claims

1-13. (canceled)

14. A portable chainsaw with motorized chain suitable for sawing and trimming objects, comprising, a. a motor housing comprising a side portion, b. a chain and a guide bar for guiding the chain, c. an electric motor for driving the chain, wherein said motor is contained in the motor housing of the chainsaw, d. a front handle, characterized in that the motor housing comprises a concave contour on part of the surface of the side portion.

15. Chainsaw according to claim 14, wherein the curvature of the concave contour is configured for fitting against a part of the leg of a user.

16. Chainsaw according to claim 14, wherein the curvature of the concave contour on part of the surface has a greater degree of curvature than the general curvature of the whole side portion.

17. Chainsaw according to claim 14, wherein the concave contour extends longitudinally at said side portion.

18. Chainsaw according to claim 14, wherein the concave contour is apertureless.

19. Chainsaw according to claim 14, wherein the radius of the curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm.

20. Chainsaw according to claim 14, wherein the longitudinal length of the curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm.

21. Chainsaw according to claim 14, wherein the part of the side portion which is configured to be in contact with the user's leg or hip is apertureless.

22. Chainsaw according to claim 14, wherein the concave contour is apertureless, wherein the longitudinal length of the curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm, and wherein the radius of the curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm.

23. Chainsaw according to claim 14, wherein the part of the side portion which is configured to be in contact with the user's body, other than the concave contour, is 2 to 20 cm long and starts from the end of the curvature of the concave contour closest to the rear portion of the chainsaw and extends in the longitudinal direction towards the rear portion of the chainsaw.

24. Chainsaw according to claim 14, wherein the concave contour is configured for being in contact with a convex contour of a user's leg.

25. Chainsaw according to claim 14, wherein 30-100% of the surface of the concave contour is configured to be in contact with a convex contour of a user's leg.

26. Chainsaw according to claim 14, further comprising an electric motor powered by at least one of a battery pack, fuel-cell, solar panel and power cord.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0032] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0033] FIG. 1 (a)(b)(c) illustrates three different embodiments of a concave contour.

[0034] FIG. 2 is a top view of an embodiment of the chainsaw according to the present invention.

[0035] FIG. 3 is a perspective view (from top-rear perspective) of the chainsaw illustrated in FIG. 2.

[0036] FIG. 4 is a perspective view (from bottom-rear perspective) of the chainsaw illustrated in FIG. 2.

DESCRIPTION OF EMBODIMENTS

[0037] The present invention relates to an ergonomic portable chainsaw having high operational safety wherein the chainsaw has a motorized chain for sawing and trimming objects such as trees and bushes. The term ergonomic chainsaw is used in the present invention to define a chainsaw which has design and configuration features, which when the chainsaw is used, will maximize productivity by minimizing operating fatigue and discomfort.

[0038] The chainsaw comprises a motor housing comprising a side portion, a chain, a guide bar for guiding the chain, an electric motor for driving the chain and a front handle. The electric motor of the chainsaw may be powered by a battery pack, a fuel-cell, a solar panel and/or a power cord. The motor housing comprises a concave contour on part of the surface of the side portion. The curvature of the concave contour is preferably configured for fitting against a part of the leg of a user. The curvature of the concave contour may alternatively be configured for fitting against a part of the hip of a user.

[0039] As previously indicated, cut through injuries occur when the user cuts through the material he or she is cutting and into their own lower extremities, generally their left upper thigh or lower legs or feet. The present invention reduces the risk of cut through injuries since concave contour fits against the user's left leg (e.g. the upper left thigh) and thereby hinders the chain saw from cutting the users left upper thigh or lower legs or feet. In other words, when the users left leg fits against the concave contour, the left leg becomes locked in that position by the curvature of the concave contour, and therefore, the movement of the chainsaw towards the extremities of the left leg is hindered. Hence, the concave contour functions as a support for the leg and provides a good ergonomic solution since the chainsaw comes closer to the body and makes a better and safer handling for the user when operating the chainsaw. In the present invention, the term ergonomic chainsaw is used to define a chainsaw which has design and configuration features, which when the chainsaw is used, will maximize productivity by minimizing operating fatigue and discomfort.

[0040] Similarly, injuries caused by kickback is also eliminated for analogous reasons. As previously disclosed, when the user operator grips the saw by the handles, the chain naturally sets dangerously close to the left leg of the user. This position becomes even more pronounced and hazardous when the user becomes fatigued and therefore brings the saw closer to the body which in turn angles the chainsaw even further left. However, the present invention hinders kickback since the user can bring the concave contour of the chainsaw against his left leg and thereby support the weight of the chainsaw on his leg. As a result, the curvature of the concave contour locks the left leg to the chainsaw and thereby the movement of the chainsaw towards the extremities of the left leg becomes difficult. Since the leg also acts as a support for the chainsaw, the user is fatigued to a lesser extent and there is also less discomfort for the user.

[0041] The curvature of the chainsaw according to the present invention can also be pressed against the hip in order to reduce or eliminate the risk of cutting the left and/or right legs.

[0042] In the above described embodiment of the invention, when the concave contour is pressed against the left leg (or right hip), the concave contour is on the side of the chainsaw facing towards the left leg (or right hip) of the user. The user of this embodiment is preferably a right-handed user. In an alternative embodiment of the invention, the chainsaw is adapted for a left-handed user who will bring the concave contour against his right leg (or left hip).

[0043] The curvature of the concave contour is dictated by its radius of curvature, which controls how steep or flat the concave contour is. The larger the radius of curvature, the flatter the curvature of the concave contour. Conversely, the shorter the radius of curvature, the steeper the curvature of the concave contour. For instance, Earth, which has a relatively large radius of curvature, appears quite flat to us as we walk across it. However, a boulderwhich has a much shorter radius of curvaturewould appear quite steep to us as we walked across its surface.

[0044] Two examples of concave contours are illustrated in FIG. 1. The concave contours shown in FIGS. 1(a) and 1(b) have the same radius of curvature, however, the lengths of the curvatures are different. The length of the curvature is the distance between the beginning of the curvature 25 and the end of the curvature 35.

[0045] It is not only the concave contour 15 which will be in contact with the user's leg or hip. The parts of the side portion which are configured to be in contact with the user's body 45, other than the concave contour, is 2 to 20 cm long and starts from the end of the curvature 35 of the concave contour closest to the rear portion of the chainsaw and extends in the longitudinal direction towards the rear portion of the chainsaw, as illustrated in FIG. 1(c).

[0046] The curvature of the concave contour has a greater degree of curvature than the general curvature of the whole side portion. This enables that the user's leg (or hip) stays in contact with the concave contour during the operation of the chainsaw. In preferred embodiments of the invention, the radius of curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm.

[0047] Moreover, the concave contour extends longitudinally at the side portion so that it fits the shape of a user's leg (or hip). The longitudinal length of the curvature of the concave contour is 2 to 20 cm, preferably 5-17 cm, more preferably 8-14 cm, most preferably 10-12 cm.

[0048] The concave contour is apertureless, i.e. there are no apertures, holes, openings or exhausts at the concave contour. Usually these types of apertures are present on one or more side portions of prior art chainsaws in order to let heat escape from the inside of the motor housing to the outside of the motor housing. Some typical examples of apertures from prior art documents is illustrated in FIG. 5 in U.S. Pat. No. 3,651,839. One disadvantage with the chainsaw disclosed in U.S. Pat. No. 3,651,839 is that the user will lean his leg or hip against the apertures when he is tired in order to support the chainsaw. However, the heat escaping from the apertures is not only a discomfort, but will also make the user fatigued which will increase the risk of lacerations and other types of injuries. Hence, in preferred embodiments of the invention, the concave contour is apertureless in order to reduce or eliminate the risk of the user becoming fatigued, i.e. in order to provide a safer chainsaw. Moreover, the concave contour being apertureless also reduces discomfort.

[0049] In some embodiments, the parts of the side portion which will be in contact with the user's body is apertureless; said parts are shown as feature (45) in FIG. 1(c). The parts of the side portion which will be in contact with the user's body is 2-20 cm long and starts from the end of the curvature closest to the rear portion of the chainsaw and extends in the longitudinal direction towards the rear portion of the chainsaw. This feature reduces or eliminates the risk of the user becoming fatigued by the warm air originating from the motor. Moreover, this features also reduces discomfort. Consequently, the risk of injuries is also reduced or eliminated.

[0050] The concave contour is substantially in contact with a convex contour of a user's leg. 30-100% of the surface of said concave contour is in contact with the user's leg, preferably 50-100% of the surface of said concave contour is in contact with the user's leg, more preferably 70-100% of the surface of said concave contour is in contact with the user's leg, most preferably 90-100% of the surface of said concave contour is in contact with the user's leg.

[0051] In some embodiments of the invention, the chainsaw comprises a chain brake lever at the front portion of the motor housing. The chain brake lever is positioned on the top portion of the front portion of the motor housing.

EXAMPLES

Example 1

[0052] Example 1 relates to a specific embodiment of the present invention. The chainsaw (1) may comprises as illustrated in FIG. 2-4: [0053] a. a motor housing (2) having [0054] i. a front portion (3), [0055] ii. a rear portion (4), [0056] iii. a top portion (5), [0057] iv. a bottom portion (6), [0058] v. a first side portion (7), i.e. left side portion when the user is facing the chain, and [0059] vi. a second side portion (8), i.e. right side portion when the user is facing the chain, [0060] b. a chain (9) and a guide bar (10) for guiding the chain, wherein the chain (9) and the guide bar (10) protrude from the front portion (3) the chainsaw (1), [0061] c. an electric motor for driving the chain (9), wherein said motor is contained in the motor housing (2) of the chainsaw, [0062] d. a hand graspable front handle (12) which extends transversely at the front portion (3) of the motor housing, [0063] e. a hand graspable rear handle (13) which extends longitudinally at the rear portion (4) of the motor housing, [0064] f. a plurality of apertures for letting heat escape from the inside of the motor housing (2), [0065] g. a chain brake lever (20), and [0066] h. a power source (30).

[0067] In the embodiment shown in FIG. 1-3, the power source (30) is a battery pack. However, a fuel-cell or solar panel may also be used as a power source. Alternatively, the chainsaw may also be connected to a power source via a power cord.

[0068] The motor housing comprises a concave contour (15) on part of the surface of the first side portion. The curvature of the concave contour is preferably configured for fitting against a part of the leg (or hip) of a user. This feature gives a good ergonomic solution, moreover, the chainsaw comes closer to the body and makes safer handling for the user when operating the product.

[0069] As illustrated in FIGS. 2-4, the curvature of the concave contour (15) has a greater degree of curvature than the general curvature of the whole side portion. This ensures that the user's leg (or hip) stays in contact with the concave contour during the operation of the chainsaw. Preferably, the concave contour will be in contact with a convex contour of a user's leg. Moreover, the concave contour extends longitudinally at the side portion so that it fits the shape of a user's leg (or hip). The concave contour is apertureless so that the user doesn't (i) feel discomfort, and (ii) become fatigued due to the heat originating from the motor.

[0070] It has been unexpectedly discovered that the combination of having a concave contour and an apertureless concave contour provides (i) an ergonomic chainsaw, and (ii) safer operation of the chainsaw.

REFERENCES

[0071] 1. Ball, J. et al. PREVENTING CHAIN SAW INJURYTHE POWER OF TRAINING AND PERSONAL PROTECTIVE EQUIPMENT, Arborist News, p. 12-17