EP0131376B1 - Chop saw linkage system - Google Patents

Chop saw linkage system Download PDF

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Publication number
EP0131376B1
EP0131376B1 EP84303810A EP84303810A EP0131376B1 EP 0131376 B1 EP0131376 B1 EP 0131376B1 EP 84303810 A EP84303810 A EP 84303810A EP 84303810 A EP84303810 A EP 84303810A EP 0131376 B1 EP0131376 B1 EP 0131376B1
Authority
EP
European Patent Office
Prior art keywords
saw
hinge
blade
chop saw
housing
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.)
Expired
Application number
EP84303810A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0131376A2 (en
EP0131376A3 (en
Inventor
Horst Kaiser
Rainer Herting
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Black and Decker Inc
Original Assignee
Black and Decker Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from DE19838317154 external-priority patent/DE8317154U1/de
Priority claimed from DE19838317153 external-priority patent/DE8317153U1/de
Application filed by Black and Decker Inc filed Critical Black and Decker Inc
Priority to AT84303810T priority Critical patent/ATE43280T1/de
Publication of EP0131376A2 publication Critical patent/EP0131376A2/en
Publication of EP0131376A3 publication Critical patent/EP0131376A3/en
Application granted granted Critical
Publication of EP0131376B1 publication Critical patent/EP0131376B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
    • B27G19/00—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws
    • B27G19/02—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws for circular saws

Definitions

  • This invention relates to table mounted, power circular saws which are primarily intended to perform a chopping function.
  • chop saws are pivotably mounted on a saw table, between a raised rest position and a lowered operational position.
  • a hood to cover the saw blade when the saw is in the rest position.
  • any such blade guard should be mounted in a manner such that it will be swung clear of the saw blade when the saw is pivoted from its rest position to its operational position.
  • Prior art devices such as German Offen- legungsschrift 28 29 297, have attempted to solve this problem by coupling the swinging hood to a saw table with a cable in order to pivot the hood to clear the blade when the saw unit is lowered to its operational position.
  • Prior art locking systems such as the one disclosed in German Gebrauchsmuster 74 20 476, keep the raised saw unit in the rest position by means of a locking element that engages a stationary locking surface. To be released, the locking element must displace a spring. In such an arrangement, the entire weight of the saw unit rests upon the locking element, which accordingly must be very rugged in order to prevent damage when the user inadvertently attempts to force the saw-unit down while the locking element remains engaged to the locking surface.
  • An object of the present invention is to overcome many of the diadvantages of prior art devices by providing a linkage system which effectively clears the blade guard from the saw blade when the chop saw is lowered to the operational position while being partially collapsible in order to facilitate changing of the saw blade by allowing the protective blade guard to be swung out of position while the saw is maintained in the rest position.
  • a chop saw pivotally mounted on a bearing bracket for movement between a lowered, operational position and a raised, rest position, having a motor-driven saw blade rotatably supported on a shaft, a housing partially encasing the saw blade and a swinging blade guard disposed to cover an exposed segment of the saw blade when the chop saw is in the raised position, whereby a linkage system is provided for moving the blade guard in response to movement of the chop saw between the lowered and raised positions, such that the blade guard immovably covers the exposed segment when the chop saw is in the raised position and is moved to uncover the exposed segment when the chop saw is moved to the lowered position
  • linkage system comprising a frame fixed to and extending upwardly from the bearing bracket, a first hinge for pivotally mounting the housing near the base of the frame member, a second hinge pivotally attaching one end of an actuation lever to the frame member upwardly from the first hinge, a third hinge pivotally attaching the other end of the actuating lever to the swinging blade guard and a fourth hinge pivotably connecting
  • the linkage system includes means for selectively disengaging the second hinging means to permit temporary shortening of the effective length of the actuation lever and moving of the blade guard to uncover the exposed segment when the chop saw is in the raised position for facilitating changing the saw blade.
  • the linkage system may include a locking device for detachably engaging the actuation lever when the saw is in the raised position.
  • the chop saw shown in the drawings includes a power circular saw-unit 90 pivotably mounted on a saw table 20 for movement between a raised rest position and a lowered operational position.
  • the saw-unit includes a prime mover preferably an electric motor (not shown), which rotatably drives-a saw blade 32 about its supporting shaft 104; a housing 106 which partially encases the blade 32 and a pivotably mounted blade guard 108 that immovably encases the exposed portion of the saw blade 32 when the saw-unit is in the rest position.
  • a linkage system is provided which clears the blade guard 108 when the saw unit 90 is lowered into the operational position, thereby exposing the blade 32 to a workpiece.
  • the linkage system schematically shown in Figure 1 includes four hinges 1, 2, and 4 as well as four effective levers 5, 6, 7 and 8.
  • the first hinge 1 is stationary and is located at the base of the lever 5 which is also stationary.
  • the lever 6 is pivotably mounted to the lower end of the lever 5 by the first hinge 1.
  • the lever 6 corresponds to the saw housing 106 of Figure 2, and the pivotal motion of the first hinge 1 corresponds to the movement of the saw-unit 90 between its rest position and its operational position.
  • the lever 8 is pivotably connected to the lever 6 by the hinge 4.
  • the lever 8 corresponds to the swinging blade guard 108 of Figure 2.
  • the lever 7 is pivotally connected to the lever 5 at hinge 2 and to the lever 8 at hinge 3.
  • the lever position depicted by solid lines in Figure 1 represent the saw in the operational position.
  • the dashed lines represent the rest position. Since the effective length of the lever 8 is substantially less than the effective length of the lever 5, the lever 8, which corresponds to the swinging blade guard 108, has a much greater arc of rotation than does the lever 6, which corresponds to movement of the housing 106 between the rest position and the operational position.
  • the lever 6' is pivoted clockwise about hinge 1. This causes a counterclockwise rotation of the lever 8 about the hinge 4. This corresponds to the movement of the swinging blade guard 108 as the saw is lowered. Since initially the distance between the hinge 3' and the hinge 1 must increase, the lever 7' is initially required to swing upwardly about the hinge 2.
  • An engaging member 10 is mounted on the lever 7.
  • engaging member 10' attaches to a locking device 12 to secure the saw in that position.
  • the hinge 3' is further from the lever 5 connecting the first and second hinges than is the hinge 4' and the two essentially form a straight line with hinge 2.
  • the alignment of the levers is such that the majority of the load acting on the saw unit is transmitted by the levers 7' and 8', thereby alleviating the bulk of the load on the locking device 12.
  • the safety saw shown in Figures 2 and 3 comprises a conventional saw table 20 with a workpiece stop 22 against which the workpiece is adapted to rest.
  • a revolving seat 24 is rotatably supported on the saw table 20 and holds a bearing bracket 26 through which passes a horizontal shaft 28.
  • a frame 105 is attached to revolving the seat 24. When a clamping knob 30 is loosened, the frame 105 may be rotated about the axis of the shaft 28. This makes possible the miter-setting of the saw-unit.
  • a shaft 101 is mounted in the frame 105 and pivotably supports the saw housing 106. This pivot-junction corresponds to the hinge 1 of Figure 1 and the housing 106 corresponds in function to the effective lever 6 of the linkage system shown in Figure 1.
  • the frame 105 extends upwardly from the shaft 101 and terminates at a pivot junction with an actuation lever 107.
  • the pivot junction is formed by a pivot bolt 102 which corresponds to the hinge 2 of Figure 1.
  • the frame 105 corresponds to the effective lever 5 of Figure 1 and the actuation lever 107 corresponds to the effective lever 7 of the linkage system shown in Figure 1.
  • the actuation lever 107 is pivotably connected to the swinging blade guard 108 by a pivot joint 103.
  • the pivot joint 103 corresponds to the hinge 3 shown in Figure 1, is eccentrically positioned on the blade guard 108 about the saw blade support shaft 104.
  • the swinging blade guard 108 corresponds to the lever 8 in Figure 1.
  • the saw blade 32 is rotatably supported by the saw blade support shaft 104 in the housing 106 and is driven by an electric motor (not shown), located on the back of the saw as seen in Figure 2.
  • the saw blade support shaft 104 shares the same axis of rotation as the swinging blade guard 108.
  • the saw blade support shaft 104 corresponds, in location, to the hinge 4 of Figure 1.
  • the actuation lever 107 is L-shaped. Such a structure assures that the actuation lever will always be outside the range of displacement of the saw blade support shaft 104. This permits the entire linkage system to be mounted essentially in a single plane.
  • the L-shaped actuation lever 107 has a pivot point aperture 40 at the outer end of its longer leg ( Figure 1). Adjoining the pivot point aperture 40 is a slot 41 which runs longitudinally along the center of the longer leg of the L-shaped actuation lever 107. The width of the slot 41 is less than the diameter of the pivot point aperture 40.
  • pivot bolt 102 has a threaded end section of lesser diameter than its shank.
  • the pivot bolt 102 is threadably secured to the frame 105.
  • the pivot point aperture 40 of the actuation lever 107 receives the shaft of the pivot bolt 102. It is preferred that the width of the slot 41 be less than the diameter of the shaft of the pivot bolt 102 but greater than the diameter of the threaded portion of the pivot bolt.
  • an opening 45 be cut into the housing 106 in a location such that it will be aligned with the pivot bolt 102 when the saw unit is in its rest position.
  • the opening 45 preferably consists of a bore 47 expanded by an inner cavity 49 internal to the housing 106.
  • the saw unit is placed in the rest position.
  • a screw driver inserted through the opening 45 in the saw housing 106 can be used to partially withdraw the pivot bolt 102 from the frame 105.
  • the face of inner cavity 49 be located in a manner such that while it prevents the pivot bolt 102 from being totally withdrawn from the frame 105, it allows sufficient space for the shank of the pivot bolt 102 to be cleared from the L-shaped actuation lever 107. This allows the actuation lever to slide freely along the threaded portions of the pivot bolt 102.
  • the swinging blade guard 108 can then be raised without moving the saw unit from its rest position.
  • the saw blade 32 may then be freely changed without any obstruction from the blade guard 108.
  • the head of the pivot bolt 102 which is within the inner cavity 49 prevents the saw-unit from being lowered to its operational position until the actuation lever 107 has been returned to its normal position and the pivot bolt 102 is turned back into place.
  • a locking element 50 engages the actuation lever 107 when the chop saw is in its rest position.
  • the locking element 50 which is pivotably mounted about a pivot axis 52, is connected to a lock release button 54 by a release lever 55.
  • the release lever itself is mounted pivotably about a pivot axis 56.
  • the locking element 50 In order to lower the saw blade so it may engage a work-piece, the locking element 50 must be disengaged. To accomplish this, the lock release button 54 is depressed. As a result, the release lever 55, which is attached at one end to lock release button 54, is rotated about the pivot axis 56. This rotation causes an upward displacement of a pin 60 which is mounted at the opposite end of the release lever 55.
  • the locking element 50 is provided with a curved slit 62 that has an enlarged clearance 64 at the lower end thereof.
  • This rotation of the locking element 50 causes the actuation lever 107 to rotate about the pivot bolt 102 in a counterclockwise direction.
  • the third hinge 103 which corresponds to hinge 3 in Figure 1, is raised above the line connecting hinges 2 and 4 (which correspond to the pivot bolt 102 and the saw blade support shaft 104 respectively), thereby eliminating the dead position.
  • the locking element 50 is disengaged and the saw unit can be easily lowered.
  • Tension springs 70 and 71 are mounted on the frame at one end and on the housing at their other end, in a manner such that they exert an upward force on the pivotably mounted housing 106.
  • the springs 70 and 71 automatically pivot the saw into the rest position shown in Figure 2 when the user releases the housing 106.
  • a threaded borehole 80 is present in the frame 105 between the points acted upon by the springs 70 and 71 on one side and the pivot bolt 102 on the other.
  • the borehole 80 is configured to receive a locking screw 83 that is mounted on the housing unit 106 in a manner such that when the saw unit is lowered into its operational position, the locking screw 83 and the borehole 80 are aligned. It is therefore possible to lock the saw unit in its lowered position, which is desirable, for example, when the saw unit is being transported.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Sawing (AREA)
  • Table Equipment (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
  • Small-Scale Networks (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
EP84303810A 1983-06-11 1984-06-06 Chop saw linkage system Expired EP0131376B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84303810T ATE43280T1 (de) 1983-06-11 1984-06-06 Stangensystem fuer kappsaege.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19838317154 DE8317154U1 (de) 1983-06-11 1983-06-11 Kappsaege
DE8317154U 1983-06-11
DE8317153U 1983-06-11
DE19838317153 DE8317153U1 (de) 1983-06-11 1983-06-11 Kappsaege

Publications (3)

Publication Number Publication Date
EP0131376A2 EP0131376A2 (en) 1985-01-16
EP0131376A3 EP0131376A3 (en) 1985-12-11
EP0131376B1 true EP0131376B1 (en) 1989-05-24

Family

ID=25949575

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84303810A Expired EP0131376B1 (en) 1983-06-11 1984-06-06 Chop saw linkage system

Country Status (7)

Country Link
EP (1) EP0131376B1 (ja)
JP (1) JPS6071113A (ja)
AT (1) ATE43280T1 (ja)
AU (1) AU560446B2 (ja)
BR (1) BR8402834A (ja)
CA (1) CA1232512A (ja)
DE (1) DE3478290D1 (ja)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2717534B2 (ja) * 1986-12-29 1998-02-18 株式会社マキタ 丸鋸盤における安全カバー装置
JPH0634897Y2 (ja) * 1987-01-12 1994-09-14 リョービ株式会社 テーブルソーのロアーガード装置
JP2627192B2 (ja) * 1989-07-08 1997-07-02 株式会社マキタ 卓上丸鋸盤
DE4010455A1 (de) * 1990-03-31 1991-10-02 Elektra Beckum Lubitz & Co Saegeeinrichtung mit pendelschutzhaube am saegeaggregat
GB9314164D0 (en) * 1993-07-08 1993-08-18 Black & Decker Inc Chop saw arrangement
JP6824639B2 (ja) * 2016-06-01 2021-02-03 株式会社マキタ 卓上切断機

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3121359A (en) * 1960-10-31 1964-02-18 Breneman Hartshorn Inc Apparatus for cutting roller shades
JPS4731737U (ja) * 1971-04-29 1972-12-09
US3834369A (en) * 1973-01-22 1974-09-10 Evans R Co Saw blade hood leveling structure
IT1049042B (it) * 1975-11-07 1981-01-20 Pedrazzoli Spa Involucro articolato per la protezione degli organi rotanti di una macchina utensile quale adesempio una troncatrice
DE2856038C2 (de) * 1978-12-23 1982-09-30 Chr. Eisele Maschinenfabrik GmbH & Co KG, 7316 Köngen Schutzvorrichtung für das Kreissägeblatt von Kippkreissägemaschinen
FR2483822A1 (fr) * 1980-06-05 1981-12-11 Roty Louis Tronconneuse pendulaire a fraise-scie
DE3119573C2 (de) * 1981-05-16 1984-02-09 Hanning Elektro-Werke Gmbh & Co, 4800 Bielefeld Kappsäge

Also Published As

Publication number Publication date
EP0131376A2 (en) 1985-01-16
ATE43280T1 (de) 1989-06-15
JPH0543442B2 (ja) 1993-07-01
JPS6071113A (ja) 1985-04-23
BR8402834A (pt) 1985-05-21
EP0131376A3 (en) 1985-12-11
AU2931584A (en) 1984-12-20
DE3478290D1 (en) 1989-06-29
AU560446B2 (en) 1987-04-09
CA1232512A (en) 1988-02-09

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