GB1015719A - Improvements in motor-driven hammers - Google Patents

Improvements in motor-driven hammers

Info

Publication number
GB1015719A
GB1015719A GB3419764A GB3419764A GB1015719A GB 1015719 A GB1015719 A GB 1015719A GB 3419764 A GB3419764 A GB 3419764A GB 3419764 A GB3419764 A GB 3419764A GB 1015719 A GB1015719 A GB 1015719A
Authority
GB
United Kingdom
Prior art keywords
springs
cylinder
piston
chamber
valve member
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
GB3419764A
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of GB1015719A publication Critical patent/GB1015719A/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D11/00—Portable percussive tools with electromotor or other motor drive
    • B25D11/06—Means for driving the impulse member
    • B25D11/12—Means for driving the impulse member comprising a crank mechanism
    • B25D11/125—Means for driving the impulse member comprising a crank mechanism with a fluid cushion between the crank drive and the striking body
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D11/00—Portable percussive tools with electromotor or other motor drive
    • B25D11/06—Means for driving the impulse member
    • B25D11/12—Means for driving the impulse member comprising a crank mechanism
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D17/06—Hammer pistons; Anvils ; Guide-sleeves for pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2211/00—Details of portable percussive tools with electromotor or other motor drive
    • B25D2211/003—Crossed drill and motor spindles

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)

Abstract

1,015,719. Percussive drills. ROBERT BOSCH G.m.b.H. Aug. 21, 1964 [Aug. 22, 1963], No. 34197/64. Heading B4C. A motor-driven hammer drill comprises an impact cylinder 8 movable within a guide cylinder 11 and in which a piston 33 is slidably driven by means of a crank 40, 41 and pre-stressed operating springs 47, an air chamber 35 adapted to act as a spring for transmitting, together with the operating springs, the driving force to the impact cylinder and for retracting the cylinder by vacuum after impact, a valve member 44 actuated by the springs 47 for controlling the air to and from the chamber, and switching means 5 adapted, regardless of the actuation of the driving motor, to prevent percussion movement of the impact cylinder if the biasing force of the operating springs has been reduced due to wear caused by the frictional engagement of the operating springs with one another or with bearings between which the springs are supported. The valve member 44 is formed with a sealing surface which is normally forced into contact with an end wall 34 of the cylinder 33 by means of the operating springs 47 located between the valve member and a gudgeon pin holder 37 retained in the piston by a ring 49. In normal operation of the hammer the piston is moved forwardly by the crank 40, 41 and connecting rod 39, the air trapped in the chamber 35 after the end 34 of the piston has passed the end of an air inlet passage 36, together with compression of the springs 47 produces a force which accelerates the cylinder 8 so that its end 9 strikes an anvil 30 abutting the tool bit 6; upon return of the piston a partial vacuum is produced in the chamber 35 thereby causing the cylinder to be drawn back with the piston until air again fills the chamber via the passage 36. In order to prevent damage to the hammer when the springs 47 become worn and lose their resilience, the switching means, in the form of a star spring 53, moves the sealing surface of the valve member 44 away from the piston end wall 34 thereby preventing a vacuum being formed in the chamber 35 to return the impact cylinder; the impacts cease even though the crank mechanism is still operating thus warning the operator of the defective springs. In a modification the valve member 44 is divided into two pieces.
GB3419764A 1963-08-22 1964-08-21 Improvements in motor-driven hammers Expired GB1015719A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEB73220A DE1209520B (en) 1963-08-22 1963-08-22 Motor-driven hammer

Publications (1)

Publication Number Publication Date
GB1015719A true GB1015719A (en) 1966-01-05

Family

ID=6977773

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3419764A Expired GB1015719A (en) 1963-08-22 1964-08-21 Improvements in motor-driven hammers

Country Status (2)

Country Link
DE (1) DE1209520B (en)
GB (1) GB1015719A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106895131A (en) * 2015-12-21 2017-06-27 博世电动工具（中国）有限公司 Sealing ventilation device and the equipment including it

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2432105A1 (en) * 1974-07-04 1976-01-22 Duss Maschf STRIKING OR ROTARY HAMMER
DE2729596A1 (en) * 1977-06-30 1979-01-11 Hilti Ag DRILL DRILL WITH PNEUMATICALLY DRIVEN PISTON
DE3828309C3 (en) * 1988-08-20 1998-07-30 Bosch Gmbh Robert Hammer drill

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE319367C (en) * 1918-06-18 1920-03-04 Automaten Handels Ges M B H De Mechanical impact tool with free-swinging bear
DE402486C (en) * 1922-04-05 1924-09-16 Heinrich Schieferstein Tool with a vibrating mass under the action of a spring
DE643844C (en) * 1933-11-20 1937-04-19 Gen Motors Corp Device for changing the camber and the pre- and post-travel of individually suspended motor vehicle wheels
DE746442C (en) * 1937-03-13 1944-08-10 Siemens Ag Spring hammer
AT220102B (en) * 1959-04-30 1962-03-12 Bosch Gmbh Robert Motor-driven hammer
US3032998A (en) * 1961-05-05 1962-05-08 Black & Decker Mfg Co Ram catcher for piston-ram assembly

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106895131A (en) * 2015-12-21 2017-06-27 博世电动工具（中国）有限公司 Sealing ventilation device and the equipment including it
CN106895131B (en) * 2015-12-21 2024-01-23 博世电动工具（中国）有限公司 Sealing ventilation device and equipment comprising same

Also Published As

Publication number Publication date
DE1209520B (en) 1966-01-20

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