Additional element for chainsaws with a spring-loaded arm that is rotatably mounted below the chain, serving as chain contact protection and cutting aid.

Abstract

Additional element for chainsaws (1) with a housing (2) and a bar (3) with a chain (4) with saw teeth (5) rotating on the bar (3), wherein a spring element (6) is arranged on the lower part (2a) of the housing (2) of the chainsaw (1), which is connected to a rotatably mounted arm (7) extending below the chain (4), wherein the spring element (6) exerts a force on the arm (7) that moves the arm (7) towards the chain (4), wherein the arm (7) does not come into contact with the chain (4) either in the operating state or in the rest state of the chainsaw (1), and the position of the arm (7) near the chain (4) minimizes the risk of the operator touching the running chain (4), and that, in an operating state of the chainsaw (1) with a material to be cut (10), the spring-loaded and movable arm (7) pushes this material (10) from the arm (7) against the chain (4) can be pressed against the underside of the sword (3), characterized by this,that a contact guard designed as a chain guard (9) is arranged at the outer end of the sword (3), and that in the rest state of the chainsaw (1) a force exerted by the spring element (6) automatically presses the arm (7) against the chain guard (9), and the arm (7) is made of a magnetic material and a permanent magnet is arranged on the lower part of the chain guard (9) to fix the arm (7).

Description

[0001] The invention relates to an additional element for chainsaws and a method for improving the cutting performance of a chainsaw. Technological background

[0002] Chainsaws have been known in many different designs for a long time. Chainsaws known from the state of the art consist of a housing, a drive mechanism, and an elongated bar with a chain and saw teeth running around the bar.

[0003] From DE 10 2005 041 204 A1 a chainsaw is known with a chain driven by an electric or combustion engine, circulating on a bar, with housing and handle with operating switches and a chain bar protruding from the housing, wherein protective devices are provided for the saw chain exiting the motor housing and running forward in its front deflection area at the outer end of the bar.

[0004] The invention is based on the objective of creating an additional element for chainsaws that is easy and inexpensive to manufacture, easy and convenient to operate, improves safety during use and enables optimal cutting performance.

[0005] The invention further aims to provide a method for improving cutting performance that can be implemented with simple process steps and results in greater ease of use. Summary of the invention

[0006] This problem is solved by the features in claims 1 and 10. Advantageous embodiments of the invention are contained in the dependent claims.

[0007] According to the invention, an additional element for chainsaws is provided, comprising a housing and a bar with a chain and saw teeth circulating on the bar. The additional element is characterized by the fact that a spring element is arranged on a lower part of the chainsaw housing, which is connected to a rotatably mounted arm extending below the chain.

[0008] A particular advantage of the invention is that the additional element minimizes the risk of touching the running chain and improves the cutting quality by pressing the material being cut against the chain, by arranging a spring element on the lower part of the housing of the chainsaw, which is connected to a rotatably mounted arm running below the chain.

[0009] The spring element according to the invention can be installed both during the industrial production of the chainsaw at the manufacturer and retrofitted by the user.

[0010] Preferably, the spring element comprises torsional spring elements arranged in a spring element housing. The shear force support provided by the spring element is achieved by arranging torsional spring elements in the spring element housing.

[0011] To allow the material being cut to pass towards the chainsaw, the arm can be bent downwards in an arc at the end not connected to the spring element.

[0012] To effectively protect the chain from contact, a chain guard can be arranged at the outer end of the guide bar. Preferably, the torsional force exerted by the torsion spring elements presses the arm against the chain guard when the chainsaw is at rest.

[0013] To further secure the arm to the chain guard, the arm can be made of a magnetic material and a permanent magnet can be arranged on the lower part of the chain guard to fix the arm.

[0014] A high visual quality of the overall construction of the chainsaw can be achieved by having a cylindrical design for the spring element housing.

[0015] The invention is applicable to cutting wood and similar materials in industry as well as in everyday life, for example in forestry, horticulture, and DIY projects. A preferred application of the invention is cutting branches and wood. The invention is also particularly suitable for chainsaws operated via a telescopic pole. Preferably, therefore, a mounting device for connecting to a telescopic pole is arranged on the housing.

[0016] Another advantage of the invention is that control functions for the operation of the chainsaw can be implemented via the additional element, for example by arranging sensors that control the start and stop as well as the speed of the motor depending on the position of the arm.

[0017] Another aspect of the invention relates to a method for improving the cutting performance of chainsaws. The method is characterized in that, during the operation of the chainsaw, the material to be cut is pressed against the chain on the underside of the guide bar by a rotatably mounted arm subjected to a torsional force.

[0018] Preferably, when at rest, the arm is pressed against the chain guard by magnetic force.

[0019] Furthermore, depending on the distance of the arm from the chain, the contact pressure on the material being cut and the speed of the motor can be varied. Brief description of the characters

[0020] The invention is explained in more detail below with reference to an exemplary embodiment and accompanying drawings. The figures show: Fig. 1 the chainsaw according to the invention with the additional element in the resting state and Fig. 2 the chainsaw according to the invention with the additional element in the operating state. Detailed description of the invention

[0021] Fig. Figure 1 shows the chainsaw 1 according to the invention with an additional element in its resting state, i.e., before the cutting process is carried out. The chainsaw 1 has a housing 2 with a lower housing part 2a. The guide bar 3 is mounted in the housing 2, on which the chain 4, driven by a motor and with saw teeth 5, is arranged circumferentially. A chain guard 9 is mounted at the front end of the guide bar 3 as contact protection.

[0022] The additional element, comprising an arm 7 and a spring element 6, is mounted on the lower part of the housing 2a just below the outlet of the chain 4, so that the arm 7 does not come into contact with the chain 4.

[0023] The arm 7 strikes the chain guard 9 at the bottom of the front end of the chainsaw blade. This provides partial contact protection when idling.

[0024] The arm 7, mounted on the lower part 2a of the housing 2, is rotatably mounted. This rotatably mounted connection leads into a spring element housing 8, designed as a cylinder in the present embodiment, with the spring element 6, which exerts a torsional force by means of torsion spring elements arranged in the spring element 6 and presses the arm 7 against the chain guard 9 independently.

[0025] In the present embodiment, the arm 7 is made of magnetic material, for example steel, and a permanent magnet arranged on the chain guard 9 additionally fixes the arm 7 to the chain guard 9.

[0026] The arm 7 is strongly curved downwards or bent in an arc shape at the other end, which is not rotatably mounted.

[0027] Fig. Figure 2 shows the chainsaw according to the invention with the additional element in its operating state, i.e., in the execution of the cutting process. The cutting process is initiated by pushing, that is, the chainsaw 1 is pushed from the front onto the material 10 to be cut, so that the material 10 comes between the opening arm 7 and the underside of the chain 4.

[0028] The front part of the arm 7 is strongly curved downwards or angled in an arc to allow the material being cut 10, in the present embodiment a part of a branch, to pass towards the chainsaw 1.

[0029] The chainsaw 1 according to the invention is particularly suitable for cutting branches on trees, even at greater heights.

[0030] In the present embodiment, the housing 2 has a receiving device 11 for connection with a telescopic rod.

[0031] Preferably, chainsaws with the additional element according to the invention are used for smaller diameters of the material 10 being cut. Further preferred applications are areas that cannot be cut directly with the chainsaw in the hand, but rather, for example, with the aid of a telescopic pole attached to the chainsaw 1. Preferred applications of the chainsaw 1 also include branches that do not end directly at a thick trunk and would otherwise spring back. Without the support of the arm 7, the chainsaw 1 would begin to "hop" or "dance" on the material 10 being cut. Here, the arm 7 provides a clamping function with cutting support.

[0032] The torsion spring elements located at the rotatably mounted end of arm 7 in the bearing area ensure that a torsion / rotation of arm 7 leads to an increase in the distance between chain 4 and arm 7.

[0033] Increasing the distance between chain 4 and arm 7 also increases the restoring force and results in a greater contact force of arm 7 towards chain 4 of the chainsaw 1. During operation of the chainsaw 1, the direction of travel of chain 4 moves the material being cut 10 towards the housing 2, and simultaneously the distance between arm 7 and chain 4 increases, consequently also increasing the restoring force of arm 7.

[0034] The resulting forces press the material being cut 10 more strongly against the running chain 4 of the chainsaw 1 and facilitate the cutting process.

[0035] The torsion in the spring element 6 can be set / pre-tensioned / adjusted at the factory or individually by the user using adjustable adjusting rings at the ends. This allows the restoring force to be variably adjusted.

[0036] The length of arm 7 is determined by the length of sword 3. Arm 7 has a semi-circular profile to ensure partial contact protection. The chain 4 is thus partially covered by arm 7. The flattened part of the arm faces the chain 4.

[0037] In a specific embodiment of the invention, the chainsaw 1 can only be started when the arm 7 is opened. For example, the motor of the chainsaw 1 only starts at a minimum speed when the stop of the arm 7 is released against the chain guard 9 as the material 10 is being fed through it. When the arm 7 is returned to the chain guard 9, with a final stop against the chain guard 9, the motor is switched off again. The drive of the chainsaw 1 is designed according to the width of the opening of the arm 7 to the chain 4; the wider the arm 7 is opened, the higher the speed of the motor of the chainsaw 1 and thus of the chain 4 with the saw teeth 5. The opening of the arm 7 can be detected by means of sensors and an electronic evaluation system and evaluated for motor control.

[0038] The invention is not limited to the embodiments shown. Rather, it is possible to realize further embodiments by combining and varying the means and features shown, without departing from the scope of the invention. Reference symbol list 1 chainsaw 2 cases 2a Lower part 3 Sword 4 chain 5 sawtooth 6 spring element 7 Arm 8 spring element housings 9 Chain guard 10 Cuttings 11 Recording device QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2005 041 204 A1

[0003]

Claims

[1] Additional element for chainsaws (1) with a housing (2) and a bar (3) with a chain (4) with saw teeth (5) running around the bar (3), characterized by , that a spring element (6) is arranged on the lower part (2a) of the housing (2) of the chainsaw (1), which is connected to a rotatably mounted arm (7) running below the chain (4). [2] Additional element according to claim 1, characterized by , that the spring element (6) has torsion spring elements arranged in a spring element housing (8). [3] Additional element according to claim 1 or 2, characterized by , that the arm (7) is bent downwards in an arc at its end which is not connected to the spring element (6). [4] Additional element according to at least one of the preceding claims, characterized by , that a contact guard designed as a chain guard plate (9) is arranged at the outer end of the sword (3). [5] Additional element according to claim 4, characterized by, that the torsional force exerted by the torsion spring elements presses the arm (7) against the chain guard (9) in the rest state. [6] Additional element according to claim 4 or 5, characterized by , that the arm (7) is made of a magnetic material and a permanent magnet is arranged on the lower part of the chain guard (9) to fix the arm (3). [7] Additional element according to claim 2, characterized by that the spring element housing is cylindrical in shape. [8] Additional element according to at least one of the preceding claims, characterized by , that a receiving device (11) for connection with a telescopic rod is arranged on the housing (2). [9] Additional element according to at least one of the preceding claims, characterized by , that sensors are arranged which control the start and stop as well as the speed of the motor depending on the position of the arm (7). [10] Methods for improving the cutting performance of chainsaws (1), characterized by , that in the operating state of the chainsaw (1) the material to be cut (10) is pressed against the chain (4) on the underside of the bar (3) by a rotatably mounted arm (7) subjected to a torsional force. [11] Method according to claim 10, characterized by , that in the resting state the arm (7) is pressed against the chain guard (9) by magnetic force. [12] Method according to claim 10 or 11, characterized by , that depending on the distance of the arm (7) from the chain (4) the pressure on the material being cut (10) and the speed of the motor are varied.

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