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EP0149874B1 - Schlagschrauber - Google Patents

Schlagschrauber Download PDF

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Publication number
EP0149874B1
EP0149874B1 EP19840300071 EP84300071A EP0149874B1 EP 0149874 B1 EP0149874 B1 EP 0149874B1 EP 19840300071 EP19840300071 EP 19840300071 EP 84300071 A EP84300071 A EP 84300071A EP 0149874 B1 EP0149874 B1 EP 0149874B1
Authority
EP
European Patent Office
Prior art keywords
projection
hammer member
spring
cylindrical rotor
engagement
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
EP19840300071
Other languages
English (en)
French (fr)
Other versions
EP0149874A3 (en
EP0149874A2 (de
Inventor
Ryoichi Shibata
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.)
Kuken Co Ltd
Original Assignee
Kuken Co Ltd
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
Application filed by Kuken Co Ltd filed Critical Kuken Co Ltd
Priority to DE8484300071T priority Critical patent/DE3470010D1/de
Priority to EP19840300071 priority patent/EP0149874B1/de
Publication of EP0149874A2 publication Critical patent/EP0149874A2/de
Publication of EP0149874A3 publication Critical patent/EP0149874A3/en
Application granted granted Critical
Publication of EP0149874B1 publication Critical patent/EP0149874B1/de
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket
    • B25B21/026—Impact clutches

Definitions

  • the present invention relates to an impact wrench for use in fastening or unfastening bolts or nuts. More particularly, the present invention relates to an impact wrench for such use, which includes a rotor driven by a motor thereby to cause the fasteners to be driven into the fixtures through the motion of the anvil hit by the rotor intermittently.
  • the known impact wrenches have a hammer portion provided by a rotor connected to a rotating shaft. While the rotor is rotated around the anvil, the hammer portion of the rotor is forced into engagement with the anvil under the action of a cam or any other similar device. The engagement of the hammer portion of the rotor occurs when the rotor rotates at a high speed, and the engagement is finished in a moment. In addition, the hammer portion is subjected to various forces while the same is in such a quick movement. Owing to these factors the fabricating of the rotor, particularly of the hammer portion, involves difficulties, and even if it is fabricated, differences in movement occur from rotor to rotor. Furthermore, as the rotor is partially abraded, it becomes difficult for the hammer portion to fall exactly on the anvil, which results in weak blows or even non- blows. This leads to incomplete fastening of fasteners.
  • JP-A-57/127678 FR-A-2498510
  • an anvil is placed inside the cylindrical rotor, such that it is ready to be hit by a projection provided on the inside surface of the rotor while the rotor rotates.
  • the anvil is subjected to a relatively large spring load, against which the anvil is positioned, until the same comes into engagement with the side of the projection. Because of this spring-loaded situation, a frictional loss tends to occur between the anvil and the inside surface of the rotor, which retards its speed. As a result, the impact expected to occur therebetween becomes weak.
  • the present invention is directed toward solving the problems pointed out with respect to the known impact wrenches, and has for its object to provide an improved impact wrench having an improved arrangement of adjusting the spring loads to be acted on theanviI member, thereby ensuring that constantly regular impacts of a large strength are transmitted to the anvil.
  • Another object of the present invention is to provide an improved impact wrench capable of producing impacts without giving detrimental shocks to the operator's hands.
  • the impact wrench includes a casing 1 with a handle 2 and a trigger 3.
  • a compressed air is introduced in the casing 1 through an inlet (not shown) in the known manner.
  • an air motor 4 is rotated at a high speed in a clockwise or a counter-clockwise direction by operating the trigger 3 and an adjusting valve (not shown).
  • the air motor 4 has a rotary shaft 6 which has a cylindrical rotor 5 integrally jointed thereto by means of splines.
  • the cylindrical rotor 5 has a circular inner surface 5a, on which a projection 7 is radially provided.
  • the projection 7 has a circumferential width, and an axial length.
  • the projection 7 has circular recesses 8a, 8b at its opposite sides, as best shown in Figure 3.
  • the reference numeral 5b designates a tail portion of the cylindrical rotor 5.
  • the reference numeral 9 designates a guide groove produced in the projection 7, which connects between the recesses 8a and 8b at their forward sides (in Figure 1).
  • An anvil 10 is rotatively provided in the casing 1.
  • the anvil 10 has a head 10a and a tail portion 11, which is fitted in the tail portion 5b of the cylindrical rotor 5, thereby effecting a unitary rotation.
  • the head 10a is made so as to be fixed to a socket (not shown) for a bolt or a nut.
  • the anvil 10 has a body portion 10b having a larger diameter, on which a groove 12 of semi-circle in cross-section is axially produced.
  • a hammer member 13 is rotatively located in the groove 12 as best shown in Figure 6.
  • the hammer member 13 is a semi-circular rod, having the same radius of curvature as that of the circular recesses 8a, 8b, and at its circular surface it is in contact with the inner surface of the groove 12.
  • the hammer member 13 has shoulder edges 13a, 13b at its opposite sides, and an outer surface 13c. It is arranged that when a line connecting transversely between the shoulder edges 13a and 13b is perpendicular to a diametrical axis of the cylindrical rotor 5, the outer surface 13c is withdrawn against the projection 7.
  • the hammer member 13 is additionally provided with a projection 14 at its forward end, which is adapted to pass through the guide groove 9.
  • the reference numeral 15 designates a bore produced in the bottom of the groove 12, the bore accommodating a pusher 16 against the hammer member 13 and a support 17 for a coil spring 22.
  • the pusher 16 is provided with a flange 16a which is adapted to slide on the inside surface of the bore 15, and with a pushing top 16b, which is kept in engagement with a curved bottom 19 of hammer member 13.
  • the reference numeral 16c designates a shank portion which is slidably received in a slot axially produced in the support 17.
  • the support 17 includes an extruding bottom 17c, which keeps contact with the inner surface of the cylindrical rotor 5.
  • the inner surface of the cylindrical rotor 5 includes a pair of continuous cam faces 20 and 21, wherein, as best shown in Figure 2, the cam face 20 is concaved with respect to another cam face 21, which is convexed with respect to the cam face 20, hereinafter the cam face 20 being referred to as the deep cam face and the cam face 21 being referred to the shallow cam face.
  • the shallow cam face 21 is opposed to the projection 7, and has such a circumferential length as to enable to the extruding bottom 7c of the support 17 to keep contact therewith in the period of time for which the hammer member 13 rotates from one side of the projection 7 to the other side thereof; actually, one shoulder edge 13a (or 13b) of hammer member 13 comes into contact with one side of the projection 7, and as the hammer member rotates, another shoulder edge 13b (or 13a) thereof comes into contact with another side of the projection 7.
  • the coil spring 22 is provided between the flange 16a and a flange produced in the pusher 17.
  • the trigger 3 and the adjusting valve (not shown) are operated to rotate the air motor 4 in a clockwise direction.
  • the cylindrical rotor 5 associated.therewith starts to rotate in a clockwise direction with respect to the hammer member 13 as shown in Figure 4.
  • the hammer member 13 is tilted with its projection 14 and left-hand shoulder edge 13a being placed in contact with the inner surface 5a of the cylindrical rotor 5.
  • the left-hand shoulder edge 13a fits in the right-hand recess 8a, and then the projection 14 comes into the circular recess 8b.
  • the left-hand shoulder edge 13a comes into engagement with the right-hand side of the projection 7, thereby transmitting the motion of the cylindrical rotor 5 to the anvil 10 through the hammer member 13.
  • the extruding bottom 17c of the spring support 17 keeps contact with the deep cam face 20, thereby weakening the strength of the spring 22 because of an enlarged distance between the pusher 16 and the spring support 17.
  • a weaker pushing force acts on the curved bottom 19 of the hammer member 13.
  • the hammer member 13 comes into engagement with the projection 7 of the cylindrical rotor 5 as it holds its tilting posture.
  • the spring 22 is caused to contract upwards thereby to enable the pusher 16 to act on the curved bottom 19 of the hammer member 13. In this way the projection 14 of the hammer member 13 is pushed upwards.
  • the period of time for which the cylindrical rotor 5 starts to rotate and allows its projection 7 to come into engagement with the hammer member 13, is instantaneous for a single rotation of the cylindrical rotor 5.
  • the projection 14 of the hammer member 13 When the projection 14 of the hammer member 13 is pushed upwards by the force of the spring 22, the projection 14 of the hammer member 13 is urged to displace from the projection 7 of the cylindrical rotor 5.
  • the strength of the spring 22 is previously adjusted so as to be larger than the static friction between the sides of the projection 7 and of hammer member 13, but smallerthan the sum of the static friction and the centrifugal force of the cylindrical rotor 5. Accordingly, the hammer member 13 is kept in engagement with the projection 7, thereby effecting the associated rotation of the cylindrical rotor 5 and the hammer member 13. In this way the anvil 10 is rotated thereby to enable bolts or nuts to rotate through the socket (not shown).
  • the projection 14 of the hammer member 13 After having passed through the guide groove 9, the projection 14 of the hammer member 13 enters the circular recess 8a, in which its top end comes into engagement with the outer end of the recess 8a. As a result, the hammer member 13 is again tilted. Immediately before it occurs, the extruding bottom 17c has been displaced on the deep cam face 20, thereby weakening the strength of the spring 22.
  • the air motor 4 When a bolt or nut is loosened, the air motor 4 is rotated in a counterclockwise direction.
  • Figure 8 diagrammatically shows the actions of the cylindrical rotor 5, the influences given by the hammer member 13 on the spring 22, and the influences given by the cam faces 20, 21 on the rotation of the cylindrical rotor 5, which are represented by (a), (b) and (c), respectively.
  • the graph (d) represents the actions of the spring 22 as a result of the synthesis of the two graphs (b) and (c).
  • Figure 8 shows that until a blow occurs, the cylindrical rotor 5 rotates in one direction, during which the force of the spring 22 is weak at the point indicated by (A). No substantial influences are given on the hammer member 13 and the cylindrical rotor 5.
  • the cylindrical rotor 5 rebounds, and simultaneously, the action of the spring 22 instantaneously becomes large.
  • the action of the spring 22 is still negligible. While the hammer member 13 passes through the guide groove 9 (at the point (C)), the force of the spring 22 becomes large, and the situation (A) is recovered in which the cylindrical rotor 5 is in free rotation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Claims (4)

1. Spannschlüssel zur Verwendung beim Festziehen von Schrauben oder Muttern gegenüber einem Bauteil mit einem zylindrischen Rotor (5), der mit einer Motorwelle (6) gekuppelt ist und einen Vorsprung (7) auf seiner Innenfläche (5a) aufweist, der eine in Umfangsrichtung sich erstreckende Breite und eine axiale Länge hat; mit einem Amboß (10), der mit dem zylindrischen Rotor verbunden ist und ein Hammerglied (13) aufweist, das in dem Rotor zu verstellen ist, um in und außer Eingriff mit dem Vorsprung gebracht werden zu können; und mit einem federbelasteten Stössei (16), um das Hammerglied außer Eingriff mit dem Vorsprung zu bringen,
dadurch gekennzeichnet, daß der federbelastete Stössel (16) einen StösseJkopf (16b) aufweist, der mittels einer Feder (22) zum Zusammenwirken mit einem gekrümmten Boden (19) des Hammergliedes (13) zu bringen ist wobei die Feder (22) mit Spannung zwischen dem Stösselkopf und einem Federwiderlager (17) sich befindet, das auf einer tiefen Kammfläche (20) und einer weniger tiefen Kammfläche (21) (aufeinanderfolgend gleitfähig) auf der Innenseite des zylindrischen Rotors (-) ist, um dabei die Federspannung aufeinanderfolgend zu erhöhen und zu verringern.
2. Spannschlüssel wie in Anspruch 1 beansprucht, bei dem die weniger tiefe Kammfläche (21) dem Vorsprung (7) gegenüberliegend angeordnet ist und eine solche Länge hat, daß das Federwiderlager (17) mit ihr in Berührung gehalten ist, während das Hammerglied (13) von einer Seite des Vorsprunges auf dessen andere Seite gedreht wird.
3. Spannschlüssel wie in Anspruch 1 oder Anspruch 2 beansprucht, bei dem ein Luftmotor als Antriebsmittel verwendet wird.
4. Spannschlüssel wie in Ansprüchen 1, 2 oder 3 beansprucht, bei dem sein gesamter Grundkörper von einem tragbaren Gehäuse aufgenommen ist, wobei ein Betätigungshebel zur manuellen Betätigung aus dem Gehäuse herausragt.
EP19840300071 1984-01-05 1984-01-05 Schlagschrauber Expired EP0149874B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE8484300071T DE3470010D1 (en) 1984-01-05 1984-01-05 An impact wrench
EP19840300071 EP0149874B1 (de) 1984-01-05 1984-01-05 Schlagschrauber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19840300071 EP0149874B1 (de) 1984-01-05 1984-01-05 Schlagschrauber

Publications (3)

Publication Number Publication Date
EP0149874A2 EP0149874A2 (de) 1985-07-31
EP0149874A3 EP0149874A3 (en) 1985-08-21
EP0149874B1 true EP0149874B1 (de) 1988-03-23

Family

ID=8192515

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840300071 Expired EP0149874B1 (de) 1984-01-05 1984-01-05 Schlagschrauber

Country Status (2)

Country Link
EP (1) EP0149874B1 (de)
DE (1) DE3470010D1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6003618A (en) * 1997-07-29 1999-12-21 Chicago Pneumatic Tool Company Twin lobe impact mechanism

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE958280C (de) * 1953-09-06 1957-02-14 Frankfurter Maschb A G Vorm Po Schlagschrauber zum Festziehen oder Loesen von Schrauben oder Muttern
SE357152B (de) * 1971-04-07 1973-06-18 Atlas Copco Ab
JPS6033628B2 (ja) * 1981-01-27 1985-08-03 株式会社 空研 インパクトレンチにおける打撃回転装置

Also Published As

Publication number Publication date
EP0149874A3 (en) 1985-08-21
DE3470010D1 (en) 1988-04-28
EP0149874A2 (de) 1985-07-31

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