QUICK-TIGHTENING DEVICE FOR A CHAIN SAW AND CHAIN UNIT FOR SAME

• US 20110314682A1
• Filed: 03/17/2010
• Published: 12/29/2011
• Est. Priority Date: 03/18/2009
• Status: Abandoned Application

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna AB (HUSQVARNA)
• Inventors: Maag, Markus, Kistler, Michael
• Application Number:
  US13/256,255
• Publication Number:
  US 20110314682A1
• Time in Patent Office: Days
• US Class Current: 30/386
• CPC Class Codes: B27B 17/14 Arrangements for stretching the chain saw

Abstract

The invention relates to a rapid tensioning apparatus as well as to a chain unit and a sword suitable for it, by means of which the placing of saw chain and sword on the main body of the chain saw can be readily carried out and a tensioning of the saw chain is made possible without problems.

In the rapid tensioning apparatus a wedge is mounted on the sword of the chain saw whereas a movable tensioning lever arrangement comprising a counterwedge is positioned on the chassis in the area of the drive shaft. In a special manner the course of the movement of the elements of the tensioning lever arrangement in the transition from the open position to the closed position is designed in such a manner that the counterwedge acts on the wedge mounted on the sword and secures the sword on the chassis by contact pressure. At the same time the sword is pushed longitudinally in the direction away from the drive pinion here by the pushing pressure so that the saw chain is tensioned.

Claims

1. A rapid tensioning apparatus for a chain saw with a drive unit for driving a saw chain running over a sword and over a drive pinion, whereby the drive pinion is connected via a drive shaft to the drive unit, whereby the sword is mounted on the chassis of the main body to be movable in a sliding manner on a support surface, whereby a wedge is mounted on the sword,

whereby a movable tensioning lever arrangement comprising a counterwedge is mounted on the chassis in the area of the drive shaft,

whereby the tensioning lever arrangement comprises a cover pivotably supported on the chassis which cover comprises an open position in which at least the saw chain and the sword are disassemblable from the main body of the chain saw, and comprises a closed position in which the saw chain rests under tension on the drive pinion and on the sword and the sword is firmly secured on the chassis of the main body,

and whereby the course of the movement of the elements of the tensioning lever arrangement during the transition from the open position to the closed position is designed in such a manner that the counterwedge comes to rest above the wedge,

so that the sword is secured by contact pressure on the chassis and at the same time the sword is pushed by pushing force longitudinally in a direction away from the drive pinion so that the saw chain is tensioned.

2. The rapid tensioning apparatus according to claim 1, wherein a counterholder is mounted in the area of the support surface of the sword, whereby this counterholder is designed to cooperate with the counterwedge, so that the contact pressure and pushing pressure between counterwedge and wedge is produced with the aid of a counterholder in that this counterholder prevents the counterwedge from escaping against the contact pressure.

3. The rapid tensioning apparatus according to claim 2, wherein a rocker arm is attached on the cover via which rocker arm the rotary movement of the cover is transformed into a longitudinal movement of a rod connected to the counterwedge

so that this rod delivers a rotary and longitudinal movement of the counterwedge.

4. The rapid tensioning apparatus according to claim 3, wherein the rod is pre-tensioned by at least one spring so that the longitudinal movement of the rod is supported by the spring force.

5. The rapid tensioning apparatus according to claim 34, wherein a movably mounted connecting web is introduced between cover and counterwedge.

6. The rapid tensioning apparatus according to claim 3, wherein it comprises a clamping mechanism that activates the rocker arm connected to the cover of the tensioning lever arrangement and acts on the rod connected to the counterwedge.

7. The rapid tensioning apparatus according to claim 6, wherein the rod is constructed in the area of its cooperation to the clamping mechanism with a gripping, in particular grooved surface.

8. The rapid tensioning apparatus according to claim 6, wherein the rod is constructed in the area of the engagement of the clamping mechanism with an elliptical cross-section,

or that in the case of a circular cross section of the rod the clamping mechanism is designed in such a manner that the cross section of the passage for the rod is constructed elliptically there.

9. The rapid tensioning apparatus according to claim 3, wherein a lever is movably fastened on the cover of the tensioning lever arrangement which lever acts upon the opening of the cover on a stop fastened on the rod and thus transforms the rotary movement of the cover into a linear movement of the rod.

10. The rapid tensioning apparatus according to claim 2, wherein the cover of the tensioning lever arrangement is provided with a fastening element by means of which it is automatically or manually fastened after the securing of the sword and after tensioning of the saw chain.

11. The rapid tensioning apparatus according to claim 1, wherein the counterwedge is connected to the cover for covering the drive pinion and to the end of the sword which end is located in its vicinity and in particular is constructed on or fastened to it,

and that this cover produces the counterforce on the counterwedge in cooperation with a locking apparatus so that the counterwedge is prevented from escaping against the contact pressure.

12. The rapid tensioning apparatus according to claim 11, wherein the locking apparatus is formed by a locking lever pivotably supported on the cover and by a locking pin formed on the chassis of the chain saw, whereby in particular the locking pin is provided with a recess into which the locking lever can engage, via a hook-shaped formation.

13. The rapid tensioning apparatus according to Claim 1, wherein the cover of the tensioning lever arrangement and a spacer located on the sword are constructed in such a manner, in particular by shifting the cover and the spacer with a nose and a counternose cooperating with the latter so that they cooperate in such a manner that upon the closure of the securing and tensioning procedure the spacer on the sword is pushed in the longitudinal direction away from the drive pinion.

14. The rapid tensioning apparatus according to claim 1, wherein a stop is formed on the chassis of the chain saw in the vicinity of the drive pinion on which stop a spacer mounted on the sword and pre-tensioned in the direction of the drive pinion comes to rest.

15. The rapid tensioning apparatus according to claim 1, wherein the driveshaft and the drive pinion are constructed in such a manner that the drive pinion is mountable on the drive shaft as part of a chain unit during the mounting of this chain unit on the chassis of the chainsaw.

16. The rapid tensioning apparatus according to claim 1, wherein the support surfaces formed in the mounting area of the chassis for supporting the sword are constructed magnetically or are provided with a magnet.

17. A chain unit for a rapid tensioning apparatus of a chain saw according to claim 1, comprising a drive shaft, a sword and a saw chain running around the drive pinion and the sword in a guide groove,

whereby a wedge is mounted on the sword,

whereby a spacer is mounted on the sword in such a manner that it is movable in a sliding manner,

whereby the spacer is pre-tensioned relative to the wedge by springs in the direction of the drive pinion,

whereby the spacer, starting from the springs, exerts such a force on the drive pinion that it is pressed counter to the sword into the saw chain.

18. A sword for a chain unit according to claim 17, wherein a wedge is mounted on the sword.

19. The sword according to claim 18, wherein a spacer is mounted on the sword in such a manner that it is shiftably moveable.

20. The sword according to claim 18, wherein the wedge is mounted on the sword in such a manner that it is shiftably moveable along a longitudinal axis of the sword,

whereby a spring force acts on the wedge in such a manner that upon the opening of the tensioning lever arrangement of the rapid tensioning apparatus the wedge is pushed on the sword in a direction of the end of the sword adjacent to the drive pinion.

21. The sword according to claim 20, wherein the wedge is connected to the sword via a microcogging, for which in particular the wedge bottom resting of the sword is provided with a microcogging that cooperates with a microcogging on the longitudinal section of the sword on which latter microcogging the wedge moves,

whereby the microcogging is designed in such a manner that the wedge is shiftable relative to the sword only in the direction toward the end of the sword adjacent to the drive pinion.

22. The sword according to claim 18, wherein in the wedge mounted on the sword preferably the middle part as well as, in a corresponding manner, the area of the sword located underneath it are recessed in particular as a longitudinal groove, and that during the placing of the chain unit on the support surface a spring supporting the adjusting of the sword is enabled to penetrate this recess.