EP0067485A2 - Sawing device - Google Patents
Sawing device Download PDFInfo
- Publication number
- EP0067485A2 EP0067485A2 EP82200709A EP82200709A EP0067485A2 EP 0067485 A2 EP0067485 A2 EP 0067485A2 EP 82200709 A EP82200709 A EP 82200709A EP 82200709 A EP82200709 A EP 82200709A EP 0067485 A2 EP0067485 A2 EP 0067485A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- clutch
- housing
- motor
- pawl
- sprocket
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
- B27B17/00—Chain saws; Equipment therefor
- B27B17/08—Drives or gearings; Devices for swivelling or tilting the chain saw
- B27B17/083—Devices for arresting movement of the saw chain
Definitions
- the invention relates to a sawing device mainly comprising a housing with handles, a motor arranged in said housing and driving through a transmission with a starting clutch a sprocket for a saw chain passed around a guide and a mechanism for putting said drive out of operation.
- the invention has for its object to provide a device provided with a mechanism such that upon actuation thereof the chain stops substantially without delay without the need for the motor to halt.
- This device is distinguished in that the mechanism comprise a member controlling a second clutch arranged between the sprocket and the starting clutch in the transmission, said member being retained against a bias force by means of a disengageable safety pawl in a position in which the clutch is in mesh.
- the control-member can be displaced by the bias force immediately after the pawl is released, said control-member putting the clutch out of operation.
- the drive between motor and sprocket is interrupted.
- the pawl is preferably actuated by a mass which is rotatable about an axis transverse of the sawing plane.
- the mass has a given inertia so that it disengages the pawl when the housing experiences and abrupt movement in the sawing plane, for example, the saw "bites".
- the mass is preferably formed by a lever which can be manually operated so that in the event of a conscious or unconscious awkward movement the user can release the pawl and cut off the drive.
- control-member is formed by a plate pivotable about an axis parallel to the driving shaft and provided with a relief rim for the axial movement of the second clutch constructed in the form of a claw clutch.
- Said plate can furthermore carry a skid which comes into contact with a brake surface connected with the sprocket.
- a disturbance-free construction is ensured because, in accordance with the invention, the control-member, the pawl and a tensile spring supplying the bias force are accomodated in a closed housing part, which is releasably fastened to the housing part holding the motor and the drive.
- the safety mechanism remains free of dust and dirt, for example, carried along by the sawdust.
- the sawing device shown in Fig. 1 mainly comprises a housing 1 with two handles 2, 3, said housing accomodating a motor, for example, an electric motor and a drive for a sawing chain 5 passed around a master blade 4.
- a motor for example, an electric motor
- Figs. 2 and 3 show more in detail the drive which comprises a gear wheel transmission 6 rotating a main driving shaft 7.
- the driving shaft 7 is provided with a claw clutch 8, the outer part 8' of which is non-rotatably, but slidably arranged on said end of the shaft.
- the inner part 8" is rotatably journalled on the shaft 7 and constitutes the core of a centrifugal clutch 9, which is coaxial with the driving shaft 7.
- the housing 10 of the centrifugal clutch is connected with a sprocket 11.
- the centrifugal clutch comprises centrifugal shoes 12, which come into contact upon rotation of the inner part 8" with the housing 10.
- the part 8' of the claw clutch can be displaced by a control-ember formed by a plate 13 (see Fig. 2), which is pivotable about a shaft 14 and accomodated in a releasable housing part 15.
- the shaft 14 is parallel to the main driving shaft 7.
- the plate has a reniform opening 15, which is narrow at the top end and has a relief rim 16 gripping below the collar 17 of the part 8' of the claw clutch.
- the width of the opening 15 exceeds the diameter of the collar 17 of the part 8' .
- the plate 13 is movable up and down in the housing part 15 around the spindle 14 by means of a handle 18 against the action of a bias force supplied by a tensile spring 19 stretched between a point 20 of the plate and a point of engagement 21 of the housing part 15.
- a spindle 22 of square cross-section On the right-hand side (see Fig. 2) below the housing part 15 holds a spindle 22 of square cross-section...
- the spindle 22 is journalled at 23 in the housing part 24 of the housing 1 comprising the motor and the transmission gear.
- the spindle 23 is bent over upwards and terminates in a handle 25 located in front of and near the handle 2 of the sawing device.
- the end of the spindle 23 located in the housing part 15 extends into a sleeve 26, which is rotatably journalled in the housing part 15.
- the sleeve has a pawl 27, which can be brought into contact with a nose 28 of the control-plate 13.
- the continuous hole in the sleeve 26 has a star-shaped cross-section such that a turn of the handle 25 in the direction of the arrow P1, that is to say, away from the handle 2 ensures a turn of the sleeve 26 and hence a turn of the pawl 27. In the reverse sense, however, a free stroke is ensured.
- control-plate 13 On the side facing the centrifugal clutch the control-plate 13 has a skid 29, which in the lowermost position of the plate 13 shown in Fig. 2 by broken lines comes into contact with the housing 10 of the centrifugal clutch which is linked to the sprocket 11.
- the device operates as follows.
- the plate 13 is turned upwards around the pin 14 so that the claw clutch parts 8' and 8" engage one another. Then the connnection between the main driving shaft 7 and the central part of the centrifugal clutch is established.
- the centrifugal clutch will become operative as a result of the rotation and the sprocket will rotate so that the chain 5 is moved along the blade 4 in the direction of the arrow P2.
- Switching off normally occurs by changing over the main switch near the handle 3 so that the motor stops and the centrifugal clutch gets out of oepration at a given number of revolutions.
- the skid 29 then comes into contact with the housing 10 of the centrifugal clutch so that the sprocket and hence the chain 5 are immediately halted.
- the motor can run on in an unaltered manner.
- the housing may be thrust upwards in the direction of the arrow P3 as the result of an abrupt shock, for example, due to "biting" of the saw at the tip, so that owing to inertia the handle 25 with the lever moves in the direction of the arrow P1 with respect to the housing 1. Then the mode of switching off is the same. As soon as the cause of the emergency stop is repaired, the user can again move the lever 18 upwards so that the claw clutch 8 becomes operative and the saw can again be used.
- the maintenance of the whole device is facilitated by accomodating the entire safety mechanism comprising the plate 13, the pawl 27, the spring 19 in the separate housing part 15 , which has a separating wall 30 on the inner side.
- the partition 30 is releasably fastened by bolts 31 in the housing part 15 and constitutes an effective screen between the sprocket 11 drawing in the sawdust and the arrangement in the housing 15.
- the partition 30 has an opening which is sufficiently large for passing the housing 10 of the centrifugal clutch, and in the engaged state of the claw clutch 8 the width of the reniform opening 15 is such that the housing part 15 with the partition 30 can be removed so that the claw clutch, the centrifugal clutch and the sprocket are freely accessible.
- the inertia mass formed by a lever may have a different shape and it need not be manually operable.
- the star-shaped hole in the sleeve 26 may be square or have a different shape.
- the claw clu-ch may be a dry-plate coupling.
Abstract
Description
- The invention relates to a sawing device mainly comprising a housing with handles, a motor arranged in said housing and driving through a transmission with a starting clutch a sprocket for a saw chain passed around a guide and a mechanism for putting said drive out of operation.
- When using chain sawing machines of the kind set forth it is important, in the event of accidents, to be able to put out of operation the drive between the motor and the chain saw as quickly as possible in order to prevent injury of the user. The hazards are even greater when the motor has high inertia as in the case of electric motors.
- The invention has for its object to provide a device provided with a mechanism such that upon actuation thereof the chain stops substantially without delay without the need for the motor to halt.
- This device is distinguished in that the mechanism comprise a member controlling a second clutch arranged between the sprocket and the starting clutch in the transmission, said member being retained against a bias force by means of a disengageable safety pawl in a position in which the clutch is in mesh.
- Thanks to the pawl mechanism the control-member can be displaced by the bias force immediately after the pawl is released, said control-member putting the clutch out of operation. Thus the drive between motor and sprocket is interrupted.
- The pawl is preferably actuated by a mass which is rotatable about an axis transverse of the sawing plane. The mass has a given inertia so that it disengages the pawl when the housing experiences and abrupt movement in the sawing plane, for example, the saw "bites". The mass is preferably formed by a lever which can be manually operated so that in the event of a conscious or unconscious awkward movement the user can release the pawl and cut off the drive.
- According to the invention a solid structure requiring little space is obtained when the control-member is formed by a plate pivotable about an axis parallel to the driving shaft and provided with a relief rim for the axial movement of the second clutch constructed in the form of a claw clutch.
- Said plate can furthermore carry a skid which comes into contact with a brake surface connected with the sprocket.
- A disturbance-free construction is ensured because, in accordance with the invention, the control-member, the pawl and a tensile spring supplying the bias force are accomodated in a closed housing part, which is releasably fastened to the housing part holding the motor and the drive. Thus the safety mechanism remains free of dust and dirt, for example, carried along by the sawdust.
- The invention will be described more fully with reference to an embodiment shown in the Figures.
- The drawing shows in
- Fig. 1 a perspective view of a sawing device,
- Fig. 2 a side elevation of the control-member used in the sawing device of Fig. 1,
- Fig. 3 a sectional view taken on the line III-III in Fig. 2.
- The sawing device shown in Fig. 1 mainly comprises a housing 1 with two handles 2, 3, said housing accomodating a motor, for example, an electric motor and a drive for a sawing chain 5 passed around a master blade 4.
- Figs. 2 and 3 show more in detail the drive which comprises a
gear wheel transmission 6 rotating amain driving shaft 7. At the end remote from thepinion 6 thedriving shaft 7 is provided with aclaw clutch 8, the outer part 8' of which is non-rotatably, but slidably arranged on said end of the shaft. Theinner part 8" is rotatably journalled on theshaft 7 and constitutes the core of a centrifugal clutch 9, which is coaxial with thedriving shaft 7. The housing 10 of the centrifugal clutch is connected with asprocket 11. The centrifugal clutch comprisescentrifugal shoes 12, which come into contact upon rotation of theinner part 8" with the housing 10. - The part 8' of the claw clutch can be displaced by a control-ember formed by a plate 13 (see Fig. 2), which is pivotable about a
shaft 14 and accomodated in areleasable housing part 15. Theshaft 14 is parallel to themain driving shaft 7. The plate has a reniform opening 15, which is narrow at the top end and has arelief rim 16 gripping below thecollar 17 of the part 8' of the claw clutch. The width of theopening 15 exceeds the diameter of thecollar 17 of the part 8' . - The
plate 13 is movable up and down in thehousing part 15 around thespindle 14 by means of ahandle 18 against the action of a bias force supplied by atensile spring 19 stretched between a point 20 of the plate and a point ofengagement 21 of thehousing part 15. - On the right-hand side (see Fig. 2) below the
housing part 15 holds aspindle 22 of square cross-section...Thespindle 22 is journalled at 23 in the housing part 24 of the housing 1 comprising the motor and the transmission gear. Thespindle 23 is bent over upwards and terminates in ahandle 25 located in front of and near the handle 2 of the sawing device. - The end of the
spindle 23 located in thehousing part 15 extends into a sleeve 26, which is rotatably journalled in thehousing part 15. The sleeve has apawl 27, which can be brought into contact with anose 28 of the control-plate 13. - The continuous hole in the sleeve 26 has a star-shaped cross-section such that a turn of the
handle 25 in the direction of the arrow P1, that is to say, away from the handle 2 ensures a turn of the sleeve 26 and hence a turn of thepawl 27. In the reverse sense, however, a free stroke is ensured. - On the side facing the centrifugal clutch the control-
plate 13 has askid 29, which in the lowermost position of theplate 13 shown in Fig. 2 by broken lines comes into contact with the housing 10 of the centrifugal clutch which is linked to thesprocket 11. - The device operates as follows.
- After the
handel 18 is moves upwards, theplate 13 is turned upwards around thepin 14 so that theclaw clutch parts 8' and 8" engage one another. Then the connnection between themain driving shaft 7 and the central part of the centrifugal clutch is established. After the motor is started, for example, by means of the conventional switches near the handle 3, the centrifugal clutch will become operative as a result of the rotation and the sprocket will rotate so that the chain 5 is moved along the blade 4 in the direction of the arrow P2. - Switching off normally occurs by changing over the main switch near the handle 3 so that the motor stops and the centrifugal clutch gets out of oepration at a given number of revolutions.
- In the event of an emergency stop the user can move the
handle 25 in the direction of the arrow P1 so that thepawl 27 turns in clockwise direction and theplate 13 is moved downwards by thetensile spring 19. This results in that theclaw clutch parts 8' and 8" are drawn away from one another so that the link of themain driving shaft 7 to the centrifugal clutch is interrupted. - The
skid 29 then comes into contact with the housing 10 of the centrifugal clutch so that the sprocket and hence the chain 5 are immediately halted. The motor can run on in an unaltered manner. - Even if the user does not touch the
lever 25, the housing may be thrust upwards in the direction of the arrow P3 as the result of an abrupt shock, for example, due to "biting" of the saw at the tip, so that owing to inertia thehandle 25 with the lever moves in the direction of the arrow P1 with respect to the housing 1. Then the mode of switching off is the same. As soon as the cause of the emergency stop is repaired, the user can again move thelever 18 upwards so that theclaw clutch 8 becomes operative and the saw can again be used. - The maintenance of the whole device is facilitated by accomodating the entire safety mechanism comprising the
plate 13, thepawl 27, thespring 19 in theseparate housing part 15 , which has a separatingwall 30 on the inner side. Thepartition 30 is releasably fastened bybolts 31 in thehousing part 15 and constitutes an effective screen between thesprocket 11 drawing in the sawdust and the compartiment in thehousing 15. Thepartition 30 has an opening which is sufficiently large for passing the housing 10 of the centrifugal clutch, and in the engaged state of theclaw clutch 8 the width of thereniform opening 15 is such that thehousing part 15 with thepartition 30 can be removed so that the claw clutch, the centrifugal clutch and the sprocket are freely accessible. - The invention is not limited to the embodiment described above. For example, the inertia mass formed by a lever may have a different shape and it need not be manually operable. The star-shaped hole in the sleeve 26 may be square or have a different shape. The claw clu-ch may be a dry-plate coupling.
Claims (10)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL8102814 | 1981-06-11 | ||
NL8102814A NL8102814A (en) | 1981-06-11 | 1981-06-11 | SAWING DEVICE. |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0067485A2 true EP0067485A2 (en) | 1982-12-22 |
EP0067485A3 EP0067485A3 (en) | 1983-08-17 |
EP0067485B1 EP0067485B1 (en) | 1987-05-06 |
Family
ID=19837620
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP82200709A Expired EP0067485B1 (en) | 1981-06-11 | 1982-06-09 | Sawing device |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0067485B1 (en) |
DE (1) | DE3276228D1 (en) |
NL (1) | NL8102814A (en) |
NO (1) | NO152537C (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5035057A (en) * | 1989-03-11 | 1991-07-30 | Heinrich Kesper | Chain guide for power chain saws |
FR2677914A1 (en) * | 1991-06-21 | 1992-12-24 | Stihl Andreas | CHAIN SAW EQUIPPED WITH AN INTEGRATED BRAKING DEVICE ON THE CHAIN WHEEL COVER. |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3991864A (en) * | 1973-10-25 | 1976-11-16 | Andreas Stihl Maschinenfabrik | Motor saw, especially motor chain saw |
FR2343567A2 (en) * | 1976-03-11 | 1977-10-07 | Stihl Andreas | Motor chain saw safety coupling - has retainer for brake band and switch held by activator against spring force |
US4053980A (en) * | 1976-09-16 | 1977-10-18 | Outboard Marine Corporation | Chain saw including an overtorque releasing clutch |
US4121339A (en) * | 1977-08-10 | 1978-10-24 | Milovan Nikolich | Safety brake mechanism for chain saws |
-
1981
- 1981-06-11 NL NL8102814A patent/NL8102814A/en not_active Application Discontinuation
-
1982
- 1982-06-08 NO NO821914A patent/NO152537C/en unknown
- 1982-06-09 EP EP82200709A patent/EP0067485B1/en not_active Expired
- 1982-06-09 DE DE8282200709T patent/DE3276228D1/en not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3991864A (en) * | 1973-10-25 | 1976-11-16 | Andreas Stihl Maschinenfabrik | Motor saw, especially motor chain saw |
FR2343567A2 (en) * | 1976-03-11 | 1977-10-07 | Stihl Andreas | Motor chain saw safety coupling - has retainer for brake band and switch held by activator against spring force |
US4053980A (en) * | 1976-09-16 | 1977-10-18 | Outboard Marine Corporation | Chain saw including an overtorque releasing clutch |
US4121339A (en) * | 1977-08-10 | 1978-10-24 | Milovan Nikolich | Safety brake mechanism for chain saws |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5035057A (en) * | 1989-03-11 | 1991-07-30 | Heinrich Kesper | Chain guide for power chain saws |
FR2677914A1 (en) * | 1991-06-21 | 1992-12-24 | Stihl Andreas | CHAIN SAW EQUIPPED WITH AN INTEGRATED BRAKING DEVICE ON THE CHAIN WHEEL COVER. |
Also Published As
Publication number | Publication date |
---|---|
NO152537B (en) | 1985-07-08 |
DE3276228D1 (en) | 1987-06-11 |
EP0067485A3 (en) | 1983-08-17 |
NL8102814A (en) | 1983-01-03 |
NO152537C (en) | 1985-10-16 |
EP0067485B1 (en) | 1987-05-06 |
NO821914L (en) | 1982-12-13 |
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