EP2774733A1 - Hand-held work device with tensioning device for a chain - Google Patents

Abstract

The device i.e. power saw, has a guide rail (8) to which a tool designed as a chain is circumferentially designed, and a housing (2). A fastening device is arranged for fixing of the guide rail on the housing. The fastening device has an actuator device (19) for fixing the guide rail. A clamping device (13) comprises a tension spring (14) that exerts a force on the guide rail. The tension spring is in operative connection with the actuator device and is clamped in a fastening direction upon actuation of the actuating unit.

Description

The invention relates to a hand-held implement with a tensioning device for a chain of the type specified in the preamble of claim 1.

From the DE 10 2006 035 744 B4 a device for automatically tensioning a chain of a power saw is known. The device has a coil spring which is supported at one end on the housing and at a second end to a Verstellnocken. To replace the chain, a separate locking cam must be operated to relax the saw chain.

The GB 2 481 038 A shows a tensioning device for a chain in which a locking device is provided, which keeps the tension spring tensioned when the sprocket cover is removed.

The invention has for its object to provide a hand-held implement with a tensioning device for a chain that allows easy tensioning and replacement of the chain.

This object is achieved by a hand-held implement with the features of claim 1.

It is envisaged that the tension spring is tensioned in the fastening direction when the actuating device is actuated. The mounting direction of the actuator is the direction in which the actuator is to operate to fix the guide rail. Accordingly, the tension spring is maximally tensioned when the fastening device fixes the guide rail. The chain is tightened when mounting the guide rail, so when operating the actuator in the mounting direction. If the fastening device is released, for example for changing the chain or the guide rail, then the tension spring is advantageously at least partially relaxed. As a result, no additional facilities are necessary to interrupt the active connection between tension spring and guide rail and keep the tension spring in a tensioned state when changing the guide rail.

Advantageously, the implement has an inhibiting device which prevents a relaxation of the tension spring in partially dissolved actuator. As a result, a return movement of the actuating device against the fastening direction during the tensioning of the tension spring is prevented. The inhibiting device advantageously comprises a friction belt which acts against a friction surface. The friction belt can advantageously come into operative connection with the actuating device and with the tension spring. When the actuating device is actuated in the fastening direction, the actuating device advantageously acts in the friction force-reducing direction on the friction belt. As a result, the frictional resistance, which the friction belt opposes to actuation in the actuating direction, that is to say the tightening of the actuating device, is reduced. The tension spring acts advantageously in the frictional force increasing direction on the friction belt. The tension spring is thereby prevented by the friction band from relaxing. When operating in the release direction is advantageously provided that the actuating device acts in the frictional force increasing direction on the friction belt. However, it can also be provided that the actuating device also acts on the friction belt during the actuation in the release direction in the friction force-reducing direction. When actuated in the fastening direction, the actuating device advantageously acts against a first end of the friction band and when actuated in the release direction against a second end of the friction band.

Advantageously, the friction band is formed integrally with the tension spring. As a result, the number of required items is reduced, and it results in a simple installation. It However, it can also be provided that the friction belt is formed separately from the tension spring. As a result, friction belt and tension spring can be easily formed. The tension spring is advantageously arranged in a separate spring housing. The arrangement of the tension spring in a separate spring housing results in a simple assembly of the overall arrangement and good protection of the tension spring from contamination. The spring housing is held in particular on the actuating device. This results in a compact design. The spring housing is advantageously arranged at least partially in the actuating device. Advantageously, the tension spring is relaxed when the fastening device is completely loosened. As a result, the clamping device can be easily removed from the guide rail or arranged on the guide rail. The tension spring may be a coil spring. Coil springs are usually arranged in a housing that receives the force exerted by the outer winding (s). Under a completely relaxed coil spring is understood in the present case a coil spring in which no spring force acts at the inner end. The outer turns can still be under tension, the force is absorbed by the spring housing. A fully relaxed coil spring is a coil spring in which the inner end does not apply torque to the outer end.

Advantageously, the tensioning of the tension spring and the maximum actuating travel of the fastening device are matched to one another. The maximum clamping travel of the tension spring is advantageously greater than the maximum actuation travel of the fastening device. This ensures that the tension spring when adjusting the actuator in the direction of actuation can not be stretched unduly wide. If the tension spring is a helical spring and the fastening device has a thread which is screwed onto a mating thread for unscrewing and loosening the guide rail or is unscrewed from the mating thread, it is advantageously provided that the permissible number of revolutions around which the ends of the tension spring when tightening the tension spring can be rotated against each other, is greater than the number of threads of the fastening device, in which the fastening device is screwed to the complete fixation of the guide rail.

The tension spring is advantageously a spiral spring, and the actuating device is rotatable in the actuating direction and in the release direction. This results in a simple, intuitive operation of the fastening device. For fixing and tensioning of guide rail or chain only the actuator must be rotated in the direction of actuation. In the process, the tension spring is tensioned, which simultaneously tensions the chain. The actuating device advantageously has a thread. The rotational movement of the actuator causes via the thread a movement of the actuator transversely to the plane of the guide rail. When the actuator is actuated, the guide rail can be clamped transversely to the plane of the guide rail via the movement of the actuating device, and the clamping device can be tensioned via the rotary movement of the actuating device. The actuator can advantageously be rotated so far until the guide rail is clamped held on the housing of the work device. To release the actuator is rotated in the release direction. At the same time the coil spring is relaxed, so that a simple replacement of the chain or the guide rail is possible. The rotational movement of the actuator in the release direction causes via the thread at the same time a movement of the actuator transverse to the plane of the guide rail, whereby the clamping of the guide rail is released.

A simple structure results when the tension spring is arranged in an at least partially limited by the actuator interior. Advantageously, the mounting region of the guide rail is covered by a sprocket cover, which has a receptacle for the tensioning device. This results in a simple, compact design. By replacing des.Kettenraddeckels the jig can be easily retrofitted to existing equipment.

Advantageously, the clamping device has a sliding link, wherein each rotational position of the sliding link is assigned a position of the guide rail. About the sliding link can be easily translated into a longitudinal movement of the guide rail caused by the clamping device rotational movement. The sliding link is in particular a spiral guide, in which a pin is guided. To one Moving the guide rail against the clamping direction to allow, for example, when the chain is straddled due to thermal distortion, is advantageously provided that the pitch angle of the spiral guide is designed so that the sliding link is not self-locking in the opposite direction of the clamping direction. This ensures that the tension in the chain does not exceed the tension provided by the tensioning device. The sliding link is advantageous in operative connection with the tension spring.

In order to reliably prevent an automatic loosening of the clamping device, for example due to vibrations during operation, it is advantageously provided that the clamping device has a securing device which secures the rotational position of the sliding link in a form-fitting manner. The securing device is advantageously designed so that it acts only immediately before reaching the fully fixed position of the actuating device, so that the actuation and release of the actuating device is not complicated by the securing device.

A simple structure results when the sliding link is formed on a spring housing of the tension spring. As a result, no separate component for the slide link is necessary.

Advantageously, the implement has a fixation for the actuator, which secures the actuator positively against a housing part. As a result, unintentional rotation of the actuating device during operation, for example due to vibrations, can be prevented. A simple design results when the actuator has a pivotable bracket which is rotatably connected in a mounting position with the housing part and in an operating position allows actuation of the actuator. As a result, a simple operation is achieved. To release the actuator, the pivotable bracket must be pivoted into the operating position. Subsequently, the actuating device can be actuated, for example rotated.

Fig. 1

eine schematische Seitenansicht einer Motorsäge,

Fig. 2

eine perspektivische Explosionsdarstellung des Befestigungsbereichs der Führungsschiene der Motorsäge aus Fig. 1,

Fig. 3

eine geschnittene Explosionsdarstellung des Befestigungsbereichs der Führungsschiene,

Fig. 4

einen Schnitt durch den Befestigungsbereich der Führungsschiene,

Fig. 5 bis Fig. 9

perspektivische Explosionsdarstellungen der Befestigungseinrichtung,

Fig. 10

eine Seitenansicht von Spannfeder, Federgehäuse und Reibband,

Fig. 11

einen Schnitt entlang der Linie XI-XI in Fig. 12,

Fig. 12

einen Schnitt durch die Betätigungseinrichtung der Motorsäge,

Fig. 13

eine perspektivische Explosionsdarstellung der Betätigungseinrichtung und des Bremsbands,

Fig. 14

eine perspektivische Ansicht der Betätigungseinrichtung und des Bremsbands,

Fig. 15

den Ausschnitt XV aus Fig. 14 in vergrößerter Darstellung,

Fig. 16

eine perspektivische Explosionsdarstellung eines Ausführungsbeispiels einer Spannvorrichtung einer Motorsäge,

Fig. 17

einen Schnitt durch die Spannvorrichtung aus Fig. 16,

Fig. 18

eine Seitenansicht des Federelements der Spannvorrichtung aus den Figuren 16 und 17,

Fig. 19

das Federelement aus Fig. 18 an einem Federgehäuse in Seitenansicht,

Fig. 20 bis Fig. 24

perspektivische Explosionsdarstellungen des Befestigungsbereichs einer Führungsschiene einer Motorsäge,

Fig. 25

einen Schnitt durch den Befestigungsbereich aus den Fig. 20 bis 24,

Fig. 26

einen Schnitt durch die Spannvorrichtung aus den Fig. 20 bis 24 im Bereich des Federelements beim Betätigen der Betätigungseinrichtung in Betätigungsrichtung,

Fig. 27

einen Schnitt durch die Anordnung aus Fig. 26 ohne das Federgehäuse bei einer Betätigung der Betätigungseinrichtung in Löserichtung.

Embodiments of the invention are explained below with reference to the drawing. Show it:

Fig. 1

a schematic side view of a power saw,

Fig. 2

an exploded perspective view of the mounting portion of the guide rail of the chainsaw Fig. 1 .

Fig. 3

a sectional exploded view of the mounting portion of the guide rail,

Fig. 4

a section through the mounting portion of the guide rail,

Fig. 5 to Fig. 9

perspective exploded views of the fastening device,

Fig. 10

a side view of tension spring, spring housing and friction belt,

Fig. 11

a section along the line XI-XI in Fig. 12 .

Fig. 12

a section through the actuating device of the power saw,

Fig. 13

an exploded perspective view of the actuator and the brake band,

Fig. 14

a perspective view of the actuator and the brake band,

Fig. 15

the cutout XV Fig. 14 in an enlarged view,

Fig. 16

an exploded perspective view of an embodiment of a clamping device of a power saw,

Fig. 17

a section through the clamping device Fig. 16 .

Fig. 18

a side view of the spring element of the tensioning device from the FIGS. 16 and 17 .

Fig. 19

the spring element Fig. 18 on a spring housing in side view,

FIGS. 20 to 24

exploded perspective views of the mounting portion of a guide rail of a power saw,

Fig. 25

a section through the attachment area of the FIGS. 20 to 24 .

Fig. 26

a section through the clamping device from the FIGS. 20 to 24 in the region of the spring element when the actuating device is actuated in the actuation direction,

Fig. 27

a section through the arrangement Fig. 26 without the spring housing upon actuation of the actuator in the release direction.

Fig. 1 shows as an exemplary embodiment of a hand-held implement a power saw 1. The power saw 1 has a housing 2 to which a guide rail 8 is fixed via a fastening device 12. On the guide rail 8, a chain 9 is guided circumferentially, which is driven by a sprocket 10. The chain 9 is formed as a saw chain. However, the implement may also be a rock cutter, in which on the guide rail 8 designed as a cutting chain chain 9 is arranged for cutting rock. To tension the chain 9, the guide rail 8 is opposite to the Housing 2 moves in a clamping direction 15, which is directed from the housing 2 in the direction of the free, projecting away from the housing 2 end of the guide rail 8. The region of the guide rail 8, which is fixed to the housing 2, as well as the sprocket 10 is covered by a sprocket 11.

To guide the power saw 1 in operation, a rear handle 3 is arranged on the housing 2, on which a throttle lever 4 and a throttle lever lock 5 are pivotally mounted. Via the throttle lever 4, a drive motor 150 arranged in the housing 2 is to be operated. In the exemplary embodiment, the drive motor 150 is designed as an internal combustion engine. However, the drive motor 150 may also be an electric motor which is connected via a connecting cable to a power supply or which is powered by a battery or a battery with energy.

The power saw 1 has a handle tube 6, which engages over the housing 2 of the power saw 1, and a hand guard 7, which extends to the guide rail 8 facing side of the handle tube 6. The hand guard 7 is advantageously used to trigger a braking device, not shown, for the chain. 9

The fastening device 12 is to be actuated via an actuating device 19, which is formed in the embodiment as a rotary. In the in Fig. 1 shown, non-actuated state of the actuator 19 closes the actuator 19 approximately flush with the outside of the sprocket 11 from. To actuate the actuator 19, a bracket 26 of the actuator 19 must be folded outward. So that the operator can grip the bracket 26 well, a recessed grip 56 is provided on the bracket 26. To release the fastening device 12, the actuator 19 is rotated in a release direction 77, which runs counterclockwise in the embodiment in the direction of rotation in the embodiment. For fixing the guide rail 8, the actuating device is rotated in a fastening direction 76. The attachment direction 76 is aligned in the exemplary embodiment in a clockwise direction. Instead of a rotary movement of the actuator 19 may also be another Movement of the actuator 19, for example, a linear movement along the sprocket 11 may be provided.

For tensioning the chain 9, the chainsaw 1 has an in Fig. 4 shown tensioning device 13. The tensioning device 13 comprises an in Fig. 4 shown tension spring 14 which is formed in the embodiment as a spiral spring. The tension spring 14 acts on a later described in more detail Verschiebekulisse, which is also part of the tensioning device 13 and the rotational movement of the tension spring 14 in a longitudinal movement of the guide rail 8 in the in Figures 1 and 2 shown clamping direction 15 converts.

Fig. 2 shows a part of the clamping device 13 in an exploded view. The arranged in the actuator 19 part of the clamping device 13 is not visible in this illustration. The sprocket 11 has a receptacle 20 whose bottom 89 has an opening 91. The opening 91 extends over a large part of the front side of the receptacle 20, so that the bottom 89 is essentially formed by a peripheral edge. The bottom 89 has a tooth contour 27, whose function will be explained in more detail below. On the outer circumference of the receptacle 20, a friction surface 18 is formed against which a friction belt 17 acts. The friction belt 17 is disposed on the outer periphery of the actuator 19 between the actuator 19 and the friction surface 18. The friction belt 17 forms with the friction surface 18 an inhibiting device 16, the function of which will be described in more detail below. The tensioning device 13 comprises a rotary element 29 and a displacement element 30, which are arranged on the inside of the sprocket cover 11 facing the housing 2. On the rotary member 29, a driver 28 is rotatably held, the rotationally fixed connection with one end of the tension spring 14 (FIG. FIGS. 3 and 4 ) serves, as will be described in more detail below. As a sliding link, the rotary member 29 a spiral guide 21. In the spiral guide 21, a pin 31 of the displacement element 30 is arranged. The displacement element 30 protrudes with in Fig. 3 retaining lugs 50 shown in openings 23 of the guide rail 8 and is thereby rotatably connected to the guide rail 8.

On the housing 2 of the power saw 1, a fastening bolt 24 and a guide pin 25 are fixed, each having a collar 32 for abutment of the guide rail 8. The fastening bolt 24 and the guide pin 25 project through a longitudinal groove 22 of the guide rail 8. The fastening bolt 24 and the guide pin 25 also protrude through a Fig. 5 As a result, the displacement element 30 and the guide rail 8 can only move in the clamping direction 15, which is aligned in the direction of the longitudinal groove 22 and the longitudinal slot 41, and in the opposite direction relative to the housing 2. A rotation of the rotary member 29 about the rotation axis 92 causes a movement of the pin 31 in the spiral guide 21. This changes the distance of the pin 31 to the rotational axis 92 of the rotary member 29. The axis of rotation 92 is the axis of rotation of the actuator 19. The displacement element 30 is in Clamping direction 15 shifted when the distance between the pin 31 and the rotation axis 92 is reduced.

As Fig. 3 shows, the driver 28, the rotary member 29 and the displacement element 30 in the direction of the axis of rotation 92 are firmly connected. To secure the connection serve a rivet sleeve 37 and a plate spring 38. The plate spring 38 causes when tightening the actuator 19 in a structurally predetermined angle range a steadily increasing torque. This gives the operator a feedback that the screw is fixed and the guide rail 8 is kept clamped. The structurally predetermined angle range can be, for example, from about 90 ° to about 360 °, in particular about 180 °. The angular range can also extend over more than 360 °.

For fixing the guide rail 8 on the displacement element 30, a fastening screw 36 may be provided, which is screwed into a retaining lug 50. As a result, when the actuating device 19 is not completely fixed, it is prevented that the retaining lugs 50 move out of the openings 23 and rest only on the guide rail 8. As Fig. 3 Also shows, a bead 49 is formed on the spiral guide 21. The rotary member 29 is advantageously made of a thick sheet, in which the spiral guide 21 is impressed. When embossing the spiral guide 21, the bead 49 is formed. The sheet can, for example have a thickness of more than 1 mm. As a result, sufficient mechanical stability of the rotary element 29 is ensured even at high forces acting on the rotary element 29.

As Fig. 3 shows, the tension spring 14 of the tensioning device 13 is disposed in an inner space 34 of the actuator 19. The actuating device 19 has a main body 39 which limits the interior space 34. On the main body 39, a threaded sleeve 33 is held. The threaded sleeve 33 can be positively connected to the base body 39 and / or be injected into the base body 39, which is advantageously a plastic part. The threaded sleeve 33 serves to screw the fastening device 12 on the fastening bolt 24, such as Fig. 4 shows.

As the 3 and 4 show, the tension spring 14 is disposed in a spring housing 40, which closes the interior 34 of the actuator 19 to the inside of the sprocket 11 towards. As a result, the tension spring 14 is protected from contamination. On the main body 39, a driver 35 is rotatably mounted. At the driver 35, the inner end of the tension spring 14 is fixed, while the outer end is rotatably connected to the main body 39. The driver 35 has at least one driving lug 58. In the embodiment, two opposing driving lugs 58 are provided, of which in Fig. 3 one is shown. Each entrainment approach 58 protrudes between Fig. 5 shown driving lugs 43 of the driver 28 and thus provides a rotationally fixed connection between the inner end of the tension spring 14 and the driver 28 ago. The driver 28 is about in Fig. 5 shown recess 44 and a pin 45 on the rotary member 29 rotatably connected to the rotary member 29. As a result, the spring force of the tension spring 14 acts on the rotary element 29.

As Fig. 4 shows, with fixed fastening device 12, the threaded sleeve 33 acts on the plate spring 38, the driver 28, the rotary member 29 and the displacement element 30 against the guide rail 8 and thereby presses the guide rail 8 against the collar 32 and in Fig. 4 schematically drawn housing 2 of the power saw 1. Advantageously, the threaded sleeve 33, the plate spring 38, the driver 28, the rotary member 29th and the displacement element 30 made of metal, so that a good fixation of the guide rail 8 results.

The main body 39 of the actuator 19 has on its front side an edge 83 which presses against the bottom 89 of the receptacle 20 and thereby presses the sprocket 11 against the housing 2, so that the sprocket 11 is well fixed. Advantageously, the base body 39 is designed so that the clamping force for fixing the sprocket 11 is introduced directly into the bottom 89 of the receptacle 20 of the sprocket 11, without further elements such as the spring housing 40 are arranged in the power flow. This can be achieved by appropriate design of the tolerances or training according to defined contact surfaces.

The FIGS. 5 to 7 show the structure of the tensioning device 13 in detail. The tensioning device 13 comprises a rivet sleeve 37 which projects through the longitudinal slot 41 of the displacement element 30, through an opening 51 in the rotary element 29, through an opening 42 in the driver 28 and through the plate spring 38. The rivet sleeve 37 causes an axially fixed, but rotatable connection of said elements together. The rotationally fixed connection of the driver 28 with the rotary member 29 is achieved via the recess 44 on the driver 28 and the pin 45 on the rotary member 29. The rotary member 29 has two driving openings 46, which are aligned so that the driving lugs 58 of the driver 35 (FIG. Fig. 3 ) can engage in the driving openings 46. As a result, in addition a direct rotationally fixed connection between the driver 35 and the rotary member 29 can be achieved. Depending on the design of the dimensions and tolerances of the driving lugs 43 of the driver 28 and the driving openings 46 in the rotary member 29, the rotationally fixed connection via the driving lugs 43, the driving openings 46 or both are achieved.

Fig. 6 shows the rotary member 29 with the rivet sleeve 37 and the plate spring 38 without the between disc spring 38 and rotary member 29 to be arranged driver 28 to illustrate the structure. The actual arrangement in which the driver 28 is disposed between the plate spring 38 and the rotary member 29 is in Fig. 7 shown.

As Fig. 5 Also shows, adjacent to the pin 31 on the displacement element 30, a securing contour 48 is formed. The securing contour 48 is arranged on the side of the journal 31 facing away from the longitudinal slot 41. The rotary element 29 has a securing contour 47 into which the securing contour 48 engages when the fastening device 12 is completely fixed. As a result, a positive connection of rotary member 29 and displacement element 30 is achieved. The securing contours 47 and 48 form a securing device 59 (FIG. Fig. 6 ), which prevents the rotary member 29 rotate in operation relative to the displacement element 30 and thus change the tension of the chain 9, in particular the chain 9 can loosen.

As Fig. 5 shows, the spiral guide 21 extends by less than one revolution about the rotation axis 92. The angle which encloses the spiral guide 21 with the circumferential direction is thereby comparatively large. As a result, the guide rail 8, the sliding element 30 against the force of the tension spring 14 move against the clamping direction 15 when the chain tension significantly exceeds the force of the tension spring 14. This may be the case, for example, when the chain 9 is tensioned in the warm state and the tensioning device 13 is then fixed. Upon cooling, the chain 9 shrinks, which significantly increases the chain tension. If necessary, the chain 9 can no longer be moved manually over the guide rail 8.

As the FIGS. 6 and 7 show, the tension spring 14 is formed as a spiral spring. The tension spring 14 has an outer end 53 which is fixed in a receptacle 55 of the spring housing 40. The tension spring 14 has an inner end 52 which is hooked to a receptacle 54 on the driver 35. The actuator 19 is rotatably connected to the spring housing 40. Rotation of the actuating device 19 in the fastening direction 76 causes the outer end 53 to move in the fastening direction 76 relative to the inner end 52 of the tension spring 14. As a result, the tension spring 14 is tensioned.

As in Fig. 6 indicated, the bracket 26 is pivotable about a pivot axis 57 relative to the base body 39 of the actuator 19. These are two in Fig. 8 shown bearing pin 61 is provided. The bearing pin 61 pivotally supports the bracket 26 on the base body 39. The bracket 26 is biased by a spring 62 in the direction of its folded into the receptacle 20 position. The bracket 26 has at least one fixing pin 60, which is approximately parallel to the axis of rotation 92 when the bracket 26 is folded in ( Fig. 4 ). The bracket 26 is in the folded state adjacent to a wall 67 of the body 39. Wie Fig. 4 shows, the wall 67 also limits the interior 34, so that the tension spring 14 is protected from contamination. The wall 67 has a recess 66 through which the fixing pin 60 protrudes. The fixing pin 60 engages in the in the Figures 2 and 3 shown tooth contour 27 at the bottom 89 of the receptacle 20 and thereby fixes the actuator 19 positively against rotation on the sprocket 11. As Fig. 2 shows, the tooth contour 27 is open to the interior of the sprocket 11. Dirt that has accumulated in the region of the tooth contour 27 is thereby pressed by the fixing pin 60 into the interior of the sprocket 11 and passes from there to the environment. A clogging of the tooth contour 27 is prevented.

As Fig. 8 also shows, the base body 39 has a toothing 64, in which a toothing 65 of the threaded sleeve 33 engages. As a result, the threaded sleeve 33 is positively held on the base body 39. It can be provided that the teeth 64 and 65 are made separately from each other and the threaded sleeve 33 is pressed into the body 39. However, the threaded sleeve 33 with the toothing 65 can also be encapsulated by the base body 39, wherein the toothing 64 is formed.

As the FIGS. 8 and 12 show, the spring housing 40 has an opening 86 through which the driver 35 protrudes. The driver 35 has an outwardly projecting, circumferential edge 87 which abuts adjacent to the opening 86 on the spring housing 40 and the driver 35 axially secures. The spring housing 40 has adjacent to the opening 86 a nozzle 88 which surrounds the region of the edge 87 of the driver 35. The entrainment approach 58 protrudes beyond the neck 88. The entrainment approach 58 has a slope 71, which serves as a guide slope when attaching the driver 35 to the driver 28 and the plugging easier. When actuating the actuating device 19 in the release direction 77 ( Fig. 11 ) causes the slope 71 that the driving lugs 58 out of engagement with the driving lugs 43 ( Fig. 7 ) of the driver 28 come as soon as the actuator 19 sufficiently far from the mounting bolt 24 ( Fig. 4 ) was unscrewed. This avoids that the tension spring 14 can be damaged by reverse rotation, so turning the tension spring 14 against its Aufziehrichtung. The arrangement of the driver 35 on the spring housing 40 is also in Fig. 9 shown.

As Fig. 9 shows, the edge 83 of the base body 39 has a recess 69, into which a formed on the edge 81 of the spring housing nose 68 protrudes. As a result, the spring housing 40 and the base body 39 are rotatably connected to each other. As Fig. 9 Also shows, the base body 39 has support ribs 82, which support the spring housing 40, which may be formed, for example, as a thin plastic injection molded part, and prevent deformation of the spring housing 40.

As Fig. 8 shows, the spring housing 40 has an actuating web 70th Fig. 10 The friction belt 17 has a first end 74 and a second end 75. The first end 74 projects between the actuating web 70 and a spring housing 40 formed on the first stop surface 78. The stop surface 78 is in Fig. 11 shown and in Fig. 10 schematically drawn. The second end 75 projects between a wall 80 of the base body 39 and a wall 93 on the bracket 26. This is in Fig. 11 shown schematically.

In completely open state of the fastening device 12, the tension spring 14 is relaxed. If the actuating device 19 is rotated in the fastening direction 76, that is to say in the illustration in FIG Fig. 10 in the clockwise direction, the base body 39 of the actuator 19 and the spring housing 40 move relative to the friction belt 17 until the first stop surface 78 comes into contact with the first end 74 of the friction belt 17. The second end 75 then still has a distance from the wall 93. The stop surface 78 takes the friction belt 17 and thereby reduces the diameter of the friction belt 17th slightly. This results in a low frictional resistance between friction belt 17 and friction surface 18, and the actuator 19 can be easily operated.

The inner end 52 of the tension spring 14 is rotatably connected to the rotary member 29. Due to the frictional resistance between the guide rail 8, the fastening bolt 24, the guide pin 25 and the housing 2 (FIG. Fig. 4 ), the inner end 52 is held stationary with a relaxed tension spring 14. As a result, the tension spring 14 is tensioned when the actuating device 19 is actuated in the fastening direction 76. As soon as the force of the tension spring 14 exceeds the frictional forces acting on the rotary element 29, the displacement element 30 and the guide rail 8, the rotary element 29 is rotated and the displacement element 30 is displaced with the guide rail 8 and the chain 9 is tensioned. The maximum clamping force of the tension spring 14 is achieved significantly before the complete fixing of the clamping device 13, so that a tensioning of the chain 9 is ensured with the desired clamping force. The threaded sleeve 33 and the fastening bolt 24 are matched to the tension spring 14 so that the tension spring 14 is not fully tensioned when the fastening device 12 is completely fixed. The maximum tension of the tension spring 14, so the number of revolutions by which the tension spring 14 can be maximally tensioned, is greater than the maximum actuation travel of the fastening device 12, that is, the number of threads by which the actuator 19 are screwed onto the mounting bolt 24 can until the guide rail 8 is clamped between the displacement element 30 and the fastening bolt 24. When turning the actuator 19 in the fastening direction 76, the threaded sleeve 33 is screwed onto the fastening bolt 24 and thereby fixed the guide rail 8. At the same time, the tension spring 14 is tensioned. The tensioning spring 14 tensions the chain 9 by displacing the guide rail 8 in the tensioning direction 15. The tensioning of the chain 9 takes place until the chain 9 is completely in contact with the guide rail 8. During the last revolution of the actuating device 19, the securing contours 47 and 48 engage one another positively Engagement, so that the rotating member 19 and the displacement member 30 can no longer rotate against each other. If the actuator 19 is further rotated in the attachment direction 76, the guide rail 8 is clamped and thereby fixed.

The displacement element 30 is along the in Fig. 5 shown line 63 slightly away from the rotary member 29 and bent to the guide rail 8 out. When the fastening device 12 is released, the securing contours 47 and 48 are not engaged with each other. Only when the displacement element 30 comes to bear against the guide rail 8 during tightening of the arrangement and the region 31 of the displacement element 30 is bent toward the rotary element 29, the securing contours 47 and 48 come into engagement with each other.

When loosening the fastening device 12, so when turning the actuator 19 in the release direction 77, the actuating web 70 comes to rest on the first end 74 of the friction belt 17. The second end 75 of the friction belt 17 is not in contact with the wall 80. Due to the movement of the actuating web 70 in the release direction 77, the friction belt 17 is slightly widened and pressed against the friction surface 18. In order to actuate the actuating device in the release direction 77, the operator must additionally overcome the frictional resistance between the friction belt 17 and the friction surface 18. The tension spring 14 also acts in the release direction 77 on the spring housing 40 and the actuator 19. When the operator releases the actuator 19 in any, not completely fixed position, the tension spring 14 moves the actuating bar 70 against the first end 74 of the friction belt 17 and causes a frictional fixation of the actuator 19. As a result, an automatic turning back of the actuator 19 due to the force of the tension spring 14 is prevented. A relaxation of the tension spring 14 in non-fixed fastening device 12 is inhibited by the inhibiting device 16. A slight relaxation of the tension spring 14 is possible until the frictional engagement of the friction belt 17 on the friction surface 18. Due to the spring constant of the coil spring formed as a tension spring 14, which causes a constant spring force over a wide range, a slight relaxation of the tension spring 14 for the function of the clamping device 13 is not relevant. If the actuator 19 is completely unscrewed from the mounting bolt 24, so the tension spring 14 is completely relaxed.

As Fig. 11 shows, the base body 19 adjacent to the actuating web 70 has a support rib 85, on which the actuating web 70 is supported. As a result, excessive deformation of the actuating web 70 is prevented by the first end 74 of the friction belt 17. As Fig. 11 Also shows, the central axis 72 of the tension spring 14 is arranged at a small distance from the axis of rotation 92 of the actuator 19. As a result, there is sufficient space for the Fixerzapfen 60 available. Characterized in that the tension spring 14 is arranged with axial offset to the axis of rotation 92, a large outer periphery of the tension spring 14 can be achieved at the same time. The central axis 72 is the geometric center of the outer turn of the tension spring 14. Fig. 11 also shows the suspension of the inner end 52 on the driver 35th Wie Fig. 11 Also shows, an area 84 of the spring housing 40 abuts against the support ribs 85.

As the FIGS. 12 to 15 show, two fixing pins 60 are provided in the embodiment. Also, a different number of fixing pins 60, for example one or three or more fixing pins 60 may be advantageous. Does a fixing pin 60 when folding the bracket 26 not on a gap, but a ridge of the tooth contour 27, this can lead to the breaking out of the tooth contour 27. In order to reduce the forces acting on the tooth contour 27 forces and avoid the breaking of the tooth contour 27, a plurality of fixing pins 60 are advantageous. At least one fixing pin 60 advantageously consists of metal or has a metallic coating. As a result, the wear on the fixing pin 60 can be reduced. Fig. 13 shows the arrangement of the portion 84 of the spring housing 40 on the support webs 82. Wie Fig. 13 also shows, the base body 39 engages positively in the spring housing 40 a. For this purpose, on both sides of the recess 69 webs 73 are formed on the base body 39, which are part of the edge 83 and against the bottom 89 of the receptacle 20 (FIG. Fig. 2 ) Act. The webs 73 partially cover the tooth contour 27. This complicates that dirt from the interior of the sprocket 11 can pass through the tooth contour 27 to the friction belt 17.

The FIGS. 13 and 14 also show the two driving lugs 58 of the driver 35, which are arranged opposite to each other.

Like the enlarged view in Fig. 15 shows the first end 74 between the stop surface 78 and the actuating bar 70. The distances to the stop surface 78 and the actuating bar 70 are significantly smaller than that of the second end 75 to the wall 80 or the wall 93. This ensures that the second end 75 can not come into contact with the wall 80 or the wall 93. The wall 93 is formed in the exemplary embodiment on a fixing pin 60. The second end 75 has no function during operation. Due to the symmetrical design of the friction belt 17, an incorrect installation of the friction belt 17 is not possible.

The FIGS. 16 to 19 show a further embodiment of an actuator 19 and a clamping device 13. The same reference numerals designate corresponding elements as in the preceding figures, reference being made to the description of the preceding figures.

The actuator 19 off Fig. 16 has a bracket 26, which has an outwardly projecting fixing pin 90. As Fig. 17 shows, a tooth contour 97 is formed on the receptacle 20, which is designed to be closed to the interior of the sprocket 11.

As Fig. 16 shows, the tensioning device 13 has a spring element 94, which comprises a tension spring 95 and an integrally formed on the tension spring 95 friction belt 96. The friction belt 96 engages around the tension spring 95 in the opposite direction to the winding direction of the tension spring 95. At the first end 74 of the friction band 96, an outer end 103 of the tension spring 95 connects. An inner end 102 of the tension spring 95 is designed for attachment to a driver 105. The driver 105 has for this purpose a receptacle 54. The driver 105 is annular and has on its inner circumference a total of four driving lugs 106. Each driving lug 106 has a slope 107 which extends over the entire end face of the driving lug 106. The tensioning device 13 comprises a rotary element 99, to which a driver 108 is integrally formed. The driver 108 may also be formed as a separate component and fixed rotatably on the rotary member 99. The driver 108 has on its outer circumference a total of four driving lugs 109, which have bevels 110 on their end facing the driver 105 side. The bevels 107 and 110 form guide slopes and facilitate the mating of the drivers 105 and 108th

The rotary element 99 has a spiral guide 111 which extends over more than two revolutions about the axis of rotation 92 (FIG. Fig. 17 ). As a result, the spiral guide 111 acts self-locking. As a result, a force acting on the guide rail 8 and on the displacement element 30 can not rotate the rotary element 99. To reduce the chain tension, the operator must manually move the rotating member 99.

As Fig. 16 Also shows, the tension spring 95 is arranged in a spring housing 100. As Fig. 17 shows, on the front side of the edge 83 of the base body 39, a cover 98 is arranged, which covers the spring housing 100 to the interior of the sprocket 11 towards. The cover 98 is advantageously fixed to the sprocket 11, for example screwed or clipped. The spring housing 100 is designed to be substantially closed to the interior 34 in the exemplary embodiment. The driver 105 is disposed between the bottom of the spring housing 100 and the cover 98. The driver 108 engages in the driver 105, whereby the driving lugs 106 and 109 come into engagement with each other. As Fig. 17 shows, the friction belt 96 surrounds the edge 83 of the body 39 and is adjacent to a friction surface 18 of the receptacle 20 is arranged. The friction belt 96 forms the inhibiting device 16 with the friction surface 18.

Fig. 18 shows the structure of the spring element 94 in detail. The tension spring 95 has a sufficient number of turns, which may correspond, for example, the number of turns in the first embodiment. For a better overview, only three of the turns of the tension spring 95 are shown in the figures. At the outer end 103 of the tension spring 95, the first end 74 of the friction belt 96 connects.

As Fig. 19 shows, the spring housing 100 is arranged coaxially with the axis of rotation 92. The spring housing 100 has a passage opening 101 through which the first end 74 of the friction belt 96 protrudes. Adjacent to the first end 74 of the friction belt 96 is on the base body 39 of the actuator 19 a stop surface 78 is formed. If the actuator 19 is moved in the fastening direction 76, so the stop surface 78 takes the friction belt 96 at the first end 74 and thereby reduces the friction between the friction belt 96 and friction surface 18. At the same time, the outer end 103 of the tension spring 95 is taken over the first end 74 and thereby tensioned the tension spring 95. When you release the actuator 19, the tension spring 95 tries to relax. It moves the first end 74 in the direction of the stop surface 78 and thereby expands the friction belt 96, which comes to rest on the friction surface 18. As a result, the movement of the actuator 19 is inhibited in the release direction 76 and thereby prevents further relaxation of the tension spring 95.

The FIGS. 20 to 27 show a further embodiment of a clamping device 13, wherein the same reference numerals as in the preceding figures denote the same elements. At the actuator 19, a driver 118 is held. The driver 118 has, as Fig. 21 shows three driving lugs 120. The driving lugs 120 protrude through openings 117 in the main body 39 of the actuator 19 and are thereby in the circumferential direction, ie in the fastening direction 76 and in the release direction 77, positively connected to the body 39. The driver 118 may also be encapsulated by the base body 39 of the actuator 19 and thereby held on the actuator 19. On bracket 26 a total of three fixing pins 60 are formed, which engage in the folded contour of the bracket 26 in the tooth contour 27 on the sprocket 11 and thereby secure the actuator 19 positively against rotation relative to the sprocket 11.

The tensioning device 13 comprises, as Fig. 20 shows a spring housing 119, on which a spiral guide 111 is formed. The spiral guide 111 corresponds to the in Fig. 16 shown spiral guide 111 and is self-locking.

As Fig. 21 1, the tensioning device 13 comprises a spring element 124 arranged in the spring housing 119. The spring housing 119 for the spring element 124 forms the rotary element of the tensioning device 13 Fig. 21 also shows, is adjacent to the spiral guide 111 formed on the spring housing 119 has a securing contour 47, which is designed as a fine toothing and with the in Fig. 23 shown fuse contour 48 on the displacement element 30 cooperates. The tensioning device 13 comprises a driver 121, which has driving lugs 122. Overall, three driving approaches 122 are provided. The distance between the driving lugs 122 is selected so that the driving lugs 120 of the driver 118 can intervene between the driving lugs 122. The tensioning device 13 also includes a sleeve 123 having an opening 127. At the opening 127 two flats 128 are formed, which are arranged opposite to each other.

Fig. 22 shows the arrangement of the spring element 124 in the spring housing 119th Wie Fig. 22 shows, the spring housing 119 has an edge 136 which surrounds the spring element 124.

As Fig. 23 shows, a rivet sleeve 129 is provided for connecting spring housing 119 and displacement element 30. The rivet sleeve 129 has opposing flats 132, which come into abutment in the mounted state on the flats 128 of the sleeve 123 and the sleeve 123 rotatably connect with the rivet sleeve 129. The flats 132 are also dimensioned so that they secure the rivet sleeve 129 rotationally fixed in the displacement element 30. As a result, a rotationally fixed connection of the sleeve 132 with the displacement element 30 is achieved. The sleeve 123 protrudes through an opening 130 in the spring housing 119 and through a plate spring 131, which is advantageously arranged on the side facing away from the displacement element 30 of the sleeve 123.

As the FIGS. 23 and 24 show, the spring element 124 comprises a tension spring 125 and a friction belt 126. The friction belt 126 is integrally formed on the inner end 134 of the tension spring 125. The friction belt 126 engages around the sleeve 123. On the outer circumference of the sleeve 123, a friction surface 137 is formed, with which the friction belt 126 cooperates. About the friction belt 126, the inner end 134 of the tension spring 125 rotatably connected to the displacement element 30 can be connected. The driver 121 engages over the sleeve 123 and the friction belt 126th

As the FIGS. 20, 21 and 25 show, the main body 39 of the actuator 19 has an edge 140. As Fig. 25 shows, the edge 136 of the spring housing 119 is adjacent to the edge 140, but has to this a distance. The main body 39 and the spring housing 119 define an interior space 34 in which the spring element 124 is arranged. Over the gap formed between the edges 136 and 140 and over the gap formed between the edge 136 and the sprocket 11, the interior 34 is open to the interior of the sprocket 11.

Fig. 26 shows a section through the spring housing 119. The tension spring 125 has an outer end 133 which is mounted on a receptacle 135 of the spring housing 116. The receptacle 135 is formed by two slots in the edge 136 of the spring housing 119. The friction belt 126 has a first end 138, which is integrally formed on the inner end 134 of the tension spring 125, and a second end 139. The two ends 138 and 139 are arranged on both sides of a driving lug 120 of the driver 118. Upon rotation of the actuating element 19 in the fastening direction 76, a driving projection 120 acts against the first end 138 of the friction belt 126 and widens the friction belt 126 thereby, so that the friction between the friction belt 126 and the friction surface 137 of the sleeve 123 (FIGS. Fig. 24 ) is reduced. About the first end 138 of the friction band 126 of the driving lug 120 acts on an adjacent driving lug 122 of the driver 121. Upon rotation of the actuating element 19 in the fastening direction 76 thereby simultaneously a sleeve of the actuating element 19, the in Fig. 4 shown sleeve 33, screwed onto the mounting bolt 24 of the chainsaw 1 and the tension spring 125 wound on the driver 121 and thereby tensioned.

If the operator lets go of the actuating device 19, the tension spring 125 pulls the first end 138 of the friction belt 126 in the direction of the entrainment approach 120 and thereby pulls the friction belt 126 tightly around the sleeve 123. Because of the rotationally fixed connection of the sleeve 123 with the rivet sleeve 129 and the displacement element 30 prevents the tension spring 125 can relax. The friction belt 126 forms an inhibiting device 16 with the friction surface 137.

If the operator presses the operating device in the release direction 77, then the driving lug 120 moves against the second end 139 of the friction belt 126, such as Fig. 27 shows. As a result, the brake band 126 is lifted slightly off the sleeve 123, and the friction on the friction surface 137 (FIG. Fig. 24 ) is reduced. As a result, the operating force in the release direction 77 is only small.

Claims (16)

Hand-guided implement with a guide rail (8) on which a chain formed as a tool (9) can be arranged circumferentially, wherein the implement a housing (2) and a fastening device (12) for fixing the guide rail (8) on the housing (2 ), wherein the fastening device (12) has an actuating device (19) which is to be actuated for fixing the guide rail (8) in a fastening direction (76), wherein the working device has a tensioning device (13) for the chain (9), and wherein the tensioning device (13) comprises a tension spring (14, 95, 125) which, when the fastening device (12) is released, exerts a force in the tensioning direction (15) of the chain (9) on the guide rail (8),
characterized in that the tension spring (14, 95, 125) is in operative connection with the actuating device (19) and is tensioned in the fastening direction (76) when the actuating device (19) is actuated. Working device according to claim 1,
characterized in that the working device has an inhibiting device (16) which prevents a relaxation of the tension spring (14, 95, 125) at partially released actuator (19). Tool according to claim 1 or 2,
characterized in that the inhibiting means (16) comprises a friction belt (17, 96, 126) acting against a friction surface (18, 137), the actuating means (19), when actuated in the actuating direction (76), decreasing in the friction force direction the friction belt (17, 96, 126) acts and wherein the tension spring (14, 95, 125) acts in the frictional force increasing direction on the friction belt (17, 96, 126). Working device according to claim 3,
characterized in that the actuating device (19) when operating in the fastening direction (76) against a first end (138) of the friction belt (126) and when operating in the release direction (77) against a second end (139) of the friction belt (126) acts. Working device according to claim 3 or 4,
characterized in that the friction belt (96, 126) is formed integrally with the tension spring (95, 125). Working device according to claim 3 or 4,
characterized in that the friction belt (17) is formed separately from the tension spring (14). Tool according to one of claims 1 to 6,
characterized in that the tension spring (14, 95, 125) is relaxed when completely dissolved fastening device (12). Tool according to one of claims 1 to 7,
characterized in that the maximum tensioning travel of the tensioning spring (14, 95, 125) is greater than the maximum actuating travel of the fastening device (12). Tool according to one of claims 1 to 8,
characterized in that the tension spring (14, 95, 125) is a spiral spring and that the actuating device (19) in the actuating direction (76) and in the release direction (77) is rotatable. Tool according to one of claims 1 to 9,
characterized in that the tension spring (14, 95, 125) in an at least partially by the actuating device (19) limited interior space (34) is arranged. Tool according to one of claims 1 to 10,
characterized in that the mounting region of the guide rail (8) is covered by a sprocket cover (11) having a receptacle (20) for the tensioning device (13). Tool according to one of claims 1 to 11,
characterized in that the clamping device (13) has a Verschiebekulisse, wherein each rotational position of the Verschiebekulisse a position of the guide rail (8) is associated. Tool according to claim 12,
characterized in that the sliding link is a spiral guide (21, 111) in which a pin (31) is guided. Tool according to claim 12 or 13,
characterized in that the sliding link is in operative connection with the tension spring (14, 95, 125). Tool according to one of claims 12 to 14,
characterized in that the tensioning device (13) has a securing device (59) which secures the rotational position of the sliding link in a form-fitting manner. Tool according to one of claims 12 to 15,
characterized in that the sliding link on a spring housing (119) of the tension spring (125) is formed.

Images