US3878902A - Impact tool - Google Patents

Impact tool Download PDF

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Publication number
US3878902A
US3878902A US343651A US34365173A US3878902A US 3878902 A US3878902 A US 3878902A US 343651 A US343651 A US 343651A US 34365173 A US34365173 A US 34365173A US 3878902 A US3878902 A US 3878902A
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United States
Prior art keywords
piston
free
cylinder
tool
pump
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Expired - Lifetime
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US343651A
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English (en)
Inventor
Susumu Matsuo
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Individual
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Individual
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Publication of US3878902A publication Critical patent/US3878902A/en
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    • 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

Definitions

  • the inventor proposed a pneumatically operated impact tool comprising an air pump cylinder having a pump piston slidably mounted therein. both the cylinders pneumatically communicating with each other, thus causing the normal reciprocation of the pump pis ton in the pump cylinder to induce an anomalousreciprocation of the free-piston in the tool cylinder. More specifically, in the impact tool above mentioned the normal reciprocation of the pump piston in the pump cylinder controls the movement of the free-piston in the tool cylinder in such a way that it uses as much time as possible to reach the top of the tool cylinder, but uses as little time as possible to reach the bottom of the tool cylinder.
  • the object of this invention is to provide a pneumatically operated impact tool in which a massive freepiston is controlled so as to generate an increased impact power.
  • the pneumatically operated impact tool comprises an air pump cylinder having a pump piston slidably mounted therein; a tool cylinder having a free-piston slidably mounted therein; the head portion of said tool cylinder having an aperture and a uni-directional exhaust port, said free-piston having a male portion which is adapted to fit in and close said aperture of the head portion; both said pump and tool cylinders being integrally connected and pneumatically communicating through a side opening made on the adjacent side walls of the cylinder housings and at the same time through said aperture and uni-directional exhaust port and through an, upper tube whose opposite ends open at the upper spaces of said cylinders; a chisel slidably mounted to the bottom of said tool cylinder and protruding therefrom into:said tool cylinder; and a crank mechanism operatively connected to said pump piston.
  • FIG. I is a longitudinal sectional view of an embodiment of the pneumatically operated impact tool according to this invention in which the free-piston is at the bottom dead point whereas the pump piston is at the top dead point.
  • FIGS. 2-1 to 2-7 are the sequential operations of the pump piston and the free-piston of this invention.
  • FIG. 3 is a graphic representation of the periodical movements of the free-piston of the impact tool of this invention (solid line), the pumppiston of the same (broken line) and the free-piston of the Japanese Patent (chain line).
  • FIG. 4 is a longitudinal sectional view of another embodiment of pneumatically operated impact tool according to this invention.
  • l is a free-piston; 2 a tool cylinder whose head portion has an aperture 2' at the center thereof; 3 a pump piston; and 4 a pump cylinder whose head portion has an aperture 4' at the center thereof.
  • Both the cylinders 2 and 4 are parallel-arranged and integrally connected, communicating with each other by an upper tube 5 whose opposite ends open at the apertures 2' and 4', and by a lower side opening 6 which is provided to the lower portions of the adjacent inner walls of the cylinders.
  • the pump cylinder 4 has a crank casing 7 at the bottom end of the cylinder housing.
  • a crank 8 contained in the crank casing is connected to a piston 3 by a piston rod.
  • Crank 8 is driven by motor 14 through belt 15 and pulley 13.
  • the chamber space defined by the crank casing and by the pump cylinder is closed in air-tight fashion except for the top aperture 4' and the side opening 6.
  • the free-piston 1 has a male portion 10 which is adapted to fit in and close the aperture 2 of the head portion when the free-piston reaches the top level of the tool cylinder, and the head portion of the tool cylinder head a port 12, which is positioned in parallel relation with the aperture 2 and contains a non-return valve means 11.
  • the free-piston 1 when driven downward. will strike against the end ofa chisel 9 with a strong force before the free-piston reaches the bottom dead point.
  • FIG. 12-] shows the state of the tool before the start of the operation. and in this case the upper remaining space 4a of the pump cylinder communicates with the upper remaining space 2a of the tool cylinder through the upper tube 5 and the lower remaining space 4b of the pump cylinder communicates with the upper remaining space 2a through the upper part of the opening 6 which is open when the free-piston l is at the bottom dead point.
  • the freepiston 1 thus is not influenced by the motion of the pump piston 3 which free to reciprocate in an idle state.
  • the chisel 9 is brought in contact with the material to be crushed to push the free-piston l upward to a position where the bottom thereof is somewhat above the bottom of the side opening 6 thus communicating thelower remaining space 2b of the tool cylinder with the lower remaining space 4b of the pump cylinder.
  • the pump piston 3 moves downward it compresses the air in both the lower remaining spaces 2b and 4b and reduces the pressure of the air in both the upper remaining spaces 20 and 4a.
  • the positive pressure of the air thus compressed and the negative pressure of the air thus expanded cause the free-piston I to move upward.
  • the free-piston 1 moves to the vicinity of the top dead point (See FIGS. 2-4).
  • the male portion 10 of the freepiston enters and closes the aperture 2' of the head portion in an air-tight fashion, thus preventing the air from passing to the upper space of the pump cylinder through the. upper tube 5. (At the same moment as the pump-piston is in the vicinity of the bottom dead point.) As a result, the free-piston rises at a reduced speed, compressing the air which is confined in the remaining space between the free-piston and the head portion of the tool cylinder.
  • the pressure of the air confined and compressed in the remaining space 2a is so increased that it overcomes the counter spring force of the non-return valve 1 l, and then the valve 11 is opened, allowing the trapped air to flow from the remaining space 2a of the tool cylinder to the upper space 4a of the pump cylinder through the port 12.
  • the free-piston 1 reaches its highest point at the time the pump piston 3 reaches the bottom dead point.
  • the pressure of the air trapped in the upper remaining space 2a is then reduced under the weight of the free piston l.
  • the pressure of air applied to each unit area of the whole upper surface of the free-piston is of a small fraction of the pressure of air applied to each unit area of the male portion, and therefore the free-piston remains at the top dead point under a state of suction, or sometimes the freepiston is allowed to descend somewhat, but the male portion thereof still does not leave the aperture 2' (See FIG. 2-7).
  • the pump piston reaches the top dead point, and when the pressure of the air in the remaining upper space 4a is increased to the maximum, the free-piston starts descending, the male portion leaves the apperture 2'.
  • the maximum positive pressure of air will apply to the whole upper surface of the free-piston, and at the same time the maximum negative'pressure of the air in the remaining lower space of the pump cylinder will apply to the whole lower surface of the free-piston through the side opening 6.
  • the free-piston thus subjected to the push-pull action will be jerked, pulling the male portion clear of the aperture 2.
  • the free-piston descends at an increased speed until it strikes against the chisel 9 (See FIG. 2-1), and then the upper space 2a of the tool cylinder communicates with the lower space 417 of the pump cylinder, thus allowing the positive pressure of air to flow from the tool cylinder to the lower space of the pump cylinder through the side opening 6.
  • the side opening 6 is somewhat shorter than the height of the free-piston 1 and can be divided into two side openings as shown in FIG. 4.
  • the free-piston 1 has a male portion 10, which is adapted to fit in and close the aperture 2' of the head portion of the tool cylinder 2 in the vicinity of the termination of the upward stroke of the freepiston I, thus closing the gas passage from the tool cylinder 2 to the pump cylinder 4;
  • the head portion of the tool cylinder has an exhaust part 12 positioned adjacent to the aperture 2' of the head portion thus allowing, after the closure by the male portion of the aperture 2, the freepiston to rise and compress the air confined in the upper remaining space 2a of the tool cylinder 2 until the pressure of the air thus compressed causes the associated non-return valve to open, and at the same time thus allowing the free-piston to rise and purge the remaining air into the gas passage to the upper space of the piston cylinder until it reaches the top dead point and is held there under suction;
  • the free-piston 1 will not start descending before the pump piston 3 has compressed the air confined in the remaining upper space of the piston cylinder 4 to the maximum because the pressure of the compressed air is applied to the large upper surface of the free-piston only via the small top surface of the male portion.
  • FIG. 3 particularly, around the top dead point of the stroke of the free-piston.
  • the ramps B, H of the curve (solid line) around the top dead point in FIG. 3 indicates that this invention permits the use of a freepiston which is heavier than that of the conventional machine, and hence the impact or smashing power of the chisel is substantially increased.
  • a pneumatic impact tool comprising in combination:
  • a tool cylinder having a free-piston slidably disposed therein, said tool cylinder having an aperture on the head portion thereof and a unidirectional port means which allows air to pass from said tool cylinder to said pump cylinder through said upper tube housing, but prevents air from otherwise passing, said free-piston having a male member disposed to pneumatically close the aperture;
  • a chisel slidably mounted into the bottom of said tool cylinder and protruding therefrom, said chisel contacting the free-piston and movable thereagainst for placing the free-piston in position to top thereof when the free-piston reaches the bottom dead point and is closed when the free-piston is elevated by the chisel, the pump piston being permitted to slidably operate in idle state when the free-piston is at the bottom dead point without effecting pneumatic movement of the free-piston.
  • a pneumatic impact tool according to claim 1 wherein the bottom surface of said free-piston has a counter sunk recess to accomodate the end of said chisel when said free-piston strikes against said chisel.
  • a pneumatic impact tool according to claim 1 wherein said common side wall opening is formed of two sections, one of which openings is sealed when the free-piston is at the bottom dead point.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
US343651A 1972-04-03 1973-03-22 Impact tool Expired - Lifetime US3878902A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47033357A JPS519199B2 (hu) 1972-04-03 1972-04-03

Publications (1)

Publication Number Publication Date
US3878902A true US3878902A (en) 1975-04-22

Family

ID=12384318

Family Applications (1)

Application Number Title Priority Date Filing Date
US343651A Expired - Lifetime US3878902A (en) 1972-04-03 1973-03-22 Impact tool

Country Status (10)

Country Link
US (1) US3878902A (hu)
JP (1) JPS519199B2 (hu)
AT (1) AT334841B (hu)
CA (1) CA971058A (hu)
CH (1) CH576317A5 (hu)
DE (1) DE2316526C3 (hu)
FR (1) FR2179007B1 (hu)
GB (1) GB1389803A (hu)
IT (1) IT980029B (hu)
SE (1) SE398834B (hu)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3995703A (en) * 1974-05-20 1976-12-07 Robert Bosch G.M.B.H. Electrohydraulically operated portable power tool
US4126191A (en) * 1977-06-03 1978-11-21 Raymond International Inc. Gas discharge type underwater hammer with liquid purge and reflood control
US4850436A (en) * 1986-01-31 1989-07-25 Hayashi Manufacturing Company, Ltd. Attached pulverulent and granular material shake-down apparatus
EP1731271A1 (de) * 2005-06-09 2006-12-13 Netter Gmbh Pneumatisch arbeitender Klopfer sowie Verfahren zum Betreiben eines pneumatisch arbeitenden Klopfers
US20080190988A1 (en) * 2007-02-09 2008-08-14 Christopher Pedicini Fastener Driving Apparatus
US20090106973A1 (en) * 2006-04-04 2009-04-30 Richardson Thomas W Apparatus and system for installing rivets in belt fasteners
US20100213235A1 (en) * 2009-02-25 2010-08-26 Christopher Pedicini Fastener Driving Apparatus
US20110108600A1 (en) * 2009-11-11 2011-05-12 Christopher Pedicini Fastener Driving Apparatus
US20110290846A1 (en) * 2007-10-05 2011-12-01 Senco Brands, Inc. Fastener driving tool using a gas spring
US8079504B1 (en) * 2010-11-04 2011-12-20 Tricord Solutions, Inc. Fastener driving apparatus
US20150129630A1 (en) * 2012-04-09 2015-05-14 Makita Corporation Driver Tool
US9050712B2 (en) 2011-01-20 2015-06-09 Black & Decker Inc. Driving tool with internal air compressor
US9844865B2 (en) 2012-04-09 2017-12-19 Makita Corporation Driver tool
US9943952B2 (en) 2013-12-11 2018-04-17 Makita Corporation Driving tool
CN108098694A (zh) * 2016-11-25 2018-06-01 南京德朔实业有限公司 动力工具
US10131047B2 (en) 2012-05-08 2018-11-20 Makita Corporation Driving tool
US10272553B2 (en) 2012-11-05 2019-04-30 Makita Corporation Driving tool
US10286534B2 (en) 2014-04-16 2019-05-14 Makita Corporation Driving tool
US10549412B2 (en) 2015-03-30 2020-02-04 Senco Brands, Inc. Lift mechanism for framing nailer
US10821585B2 (en) 2016-12-22 2020-11-03 Kyocera Senco Industrial Tools, Inc. Fastener driving tool with driver position sensors
US10898994B2 (en) 2018-04-20 2021-01-26 Kyocera Senco Industrial Tools, Inc. Lift mechanism for framing nailer
US11110577B2 (en) * 2017-11-16 2021-09-07 Milwaukee Electric Tool Corporation Pneumatic fastener driver
US11185971B2 (en) 2018-08-28 2021-11-30 Kyocera Senco Industrial Tools, Inc. Forced air cooling from piston movements of nailer tool
US11413734B2 (en) 2018-10-17 2022-08-16 Kyocera Senco Industrial Tools, Inc. Working cylinder for power tool with piston lubricating system
US11819989B2 (en) 2020-07-07 2023-11-21 Techtronic Cordless Gp Powered fastener driver
US11850714B2 (en) 2021-07-16 2023-12-26 Techtronic Cordless Gp Powered fastener driver
US11904446B2 (en) 2020-05-07 2024-02-20 Kyocera Senco Industrial Tools, Inc. Power driving tool with latch position sensor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US964875A (en) * 1907-01-23 1910-07-19 Harry Johan Hjalmar Nathorst Rock-drill.
US974267A (en) * 1908-10-12 1910-11-01 John J Hennessy Drilling apparatus.
US1319975A (en) * 1919-10-28 William a
US1829609A (en) * 1929-05-06 1931-10-27 Frank R Robinson Pneumatic hammer
US3568780A (en) * 1969-03-15 1971-03-09 Daiichi Kikai Seisakusho Co Lt Free-piston-type percussion device with air pump

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1319975A (en) * 1919-10-28 William a
US964875A (en) * 1907-01-23 1910-07-19 Harry Johan Hjalmar Nathorst Rock-drill.
US974267A (en) * 1908-10-12 1910-11-01 John J Hennessy Drilling apparatus.
US1829609A (en) * 1929-05-06 1931-10-27 Frank R Robinson Pneumatic hammer
US3568780A (en) * 1969-03-15 1971-03-09 Daiichi Kikai Seisakusho Co Lt Free-piston-type percussion device with air pump

Cited By (54)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3995703A (en) * 1974-05-20 1976-12-07 Robert Bosch G.M.B.H. Electrohydraulically operated portable power tool
US4126191A (en) * 1977-06-03 1978-11-21 Raymond International Inc. Gas discharge type underwater hammer with liquid purge and reflood control
US4850436A (en) * 1986-01-31 1989-07-25 Hayashi Manufacturing Company, Ltd. Attached pulverulent and granular material shake-down apparatus
US7607490B2 (en) 2005-06-09 2009-10-27 Netter Gmbh Pneumatic impact tool and method
EP1731271A1 (de) * 2005-06-09 2006-12-13 Netter Gmbh Pneumatisch arbeitender Klopfer sowie Verfahren zum Betreiben eines pneumatisch arbeitenden Klopfers
EP1731272A2 (de) * 2005-06-09 2006-12-13 Netter Gmbh Pneumatisch arbeitender Klopfer sowie Verfahren zum Betreiben eines pneumatisch arbeitenden Klopfers
US20060278415A1 (en) * 2005-06-09 2006-12-14 Netter Gmbh Pneumatic impact tool and method
EP1731272A3 (de) * 2005-06-09 2007-11-14 Netter Gmbh Pneumatisch arbeitender Klopfer sowie Verfahren zum Betreiben eines pneumatisch arbeitenden Klopfers
US20090106973A1 (en) * 2006-04-04 2009-04-30 Richardson Thomas W Apparatus and system for installing rivets in belt fasteners
US8875969B2 (en) * 2007-02-09 2014-11-04 Tricord Solutions, Inc. Fastener driving apparatus
US20080190988A1 (en) * 2007-02-09 2008-08-14 Christopher Pedicini Fastener Driving Apparatus
US11845167B2 (en) 2007-10-05 2023-12-19 Kyocera Senco Industrial Tools, Inc. Fastener driving tool using a gas spring
US10478954B2 (en) 2007-10-05 2019-11-19 Senco Brands, Inc. Fastener driving tool using a gas spring
US11034007B2 (en) 2007-10-05 2021-06-15 Kyocera Senco Industrial Tools, Inc. Fastener driving tool using a gas spring
US20110290846A1 (en) * 2007-10-05 2011-12-01 Senco Brands, Inc. Fastener driving tool using a gas spring
US20110315736A1 (en) * 2007-10-05 2011-12-29 Senco Brands, Inc. Fastener driving tool using a gas spring
US8267297B2 (en) * 2007-10-05 2012-09-18 Senco Brands, Inc. Fastener driving tool using a gas spring
US8267296B2 (en) * 2007-10-05 2012-09-18 Senco Brands, Inc. Fastener driving tool using a gas spring
US11241776B2 (en) 2007-10-05 2022-02-08 Kyocera Senco Industrial Tools, Inc. Fastener driving tool using a gas spring
US9676088B2 (en) 2007-10-05 2017-06-13 Senco Brands, Inc. Fastener driving tool using a gas spring
US8602282B2 (en) 2007-10-05 2013-12-10 Senco Brands, Inc. Fastener driving tool using a gas spring
USRE44001E1 (en) * 2009-02-25 2013-02-19 Tricord Solutions, Inc. Fastener driving apparatus
US20100213235A1 (en) * 2009-02-25 2010-08-26 Christopher Pedicini Fastener Driving Apparatus
US7793811B1 (en) * 2009-02-25 2010-09-14 Tricord Solutions, Inc. Fastener driving apparatus
US8523035B2 (en) * 2009-11-11 2013-09-03 Tricord Solutions, Inc. Fastener driving apparatus
US20110108600A1 (en) * 2009-11-11 2011-05-12 Christopher Pedicini Fastener Driving Apparatus
US8079504B1 (en) * 2010-11-04 2011-12-20 Tricord Solutions, Inc. Fastener driving apparatus
US10343271B2 (en) 2011-01-20 2019-07-09 Black & Decker Inc. Driving tool with internal air compressor
US9050712B2 (en) 2011-01-20 2015-06-09 Black & Decker Inc. Driving tool with internal air compressor
US9844865B2 (en) 2012-04-09 2017-12-19 Makita Corporation Driver tool
US9827659B2 (en) * 2012-04-09 2017-11-28 Makita Corporation Driver tool
US20150129630A1 (en) * 2012-04-09 2015-05-14 Makita Corporation Driver Tool
US10131047B2 (en) 2012-05-08 2018-11-20 Makita Corporation Driving tool
US10272553B2 (en) 2012-11-05 2019-04-30 Makita Corporation Driving tool
US9943952B2 (en) 2013-12-11 2018-04-17 Makita Corporation Driving tool
US10286534B2 (en) 2014-04-16 2019-05-14 Makita Corporation Driving tool
US11491624B2 (en) 2015-03-30 2022-11-08 Kyocera Senco Industrial Tools, Inc. Lift mechanism for framing nailer
US10549412B2 (en) 2015-03-30 2020-02-04 Senco Brands, Inc. Lift mechanism for framing nailer
US11890734B2 (en) 2015-03-30 2024-02-06 Kyocera Senco Industrial Tools, Inc. Lift mechanism for framing nailer
CN108098694A (zh) * 2016-11-25 2018-06-01 南京德朔实业有限公司 动力工具
CN108098694B (zh) * 2016-11-25 2020-09-01 南京德朔实业有限公司 动力工具
US10525577B2 (en) * 2016-11-25 2020-01-07 Nanjing Chervon Industry Co., Ltd. Power tool
US10821585B2 (en) 2016-12-22 2020-11-03 Kyocera Senco Industrial Tools, Inc. Fastener driving tool with driver position sensors
US11731254B2 (en) 2016-12-22 2023-08-22 Kyocera Senco Industrial Tools, Inc. Fastener driving tool with driver position sensors
US20210370487A1 (en) * 2017-11-16 2021-12-02 Milwaukee Electric Tool Corporation Pneumatic fastener driver
US11110577B2 (en) * 2017-11-16 2021-09-07 Milwaukee Electric Tool Corporation Pneumatic fastener driver
US11897106B2 (en) * 2017-11-16 2024-02-13 Milwaukee Electric Tool Corporation Pneumatic fastener driver
US10898994B2 (en) 2018-04-20 2021-01-26 Kyocera Senco Industrial Tools, Inc. Lift mechanism for framing nailer
US11571801B2 (en) 2018-08-28 2023-02-07 Kyocera Senco Industrial Tools, Inc. Forced air cooling from piston movements of nailer tool
US11185971B2 (en) 2018-08-28 2021-11-30 Kyocera Senco Industrial Tools, Inc. Forced air cooling from piston movements of nailer tool
US11413734B2 (en) 2018-10-17 2022-08-16 Kyocera Senco Industrial Tools, Inc. Working cylinder for power tool with piston lubricating system
US11904446B2 (en) 2020-05-07 2024-02-20 Kyocera Senco Industrial Tools, Inc. Power driving tool with latch position sensor
US11819989B2 (en) 2020-07-07 2023-11-21 Techtronic Cordless Gp Powered fastener driver
US11850714B2 (en) 2021-07-16 2023-12-26 Techtronic Cordless Gp Powered fastener driver

Also Published As

Publication number Publication date
DE2316526A1 (de) 1973-10-18
JPS48100768A (hu) 1973-12-19
FR2179007A1 (hu) 1973-11-16
DE2316526C3 (de) 1978-05-03
IT980029B (it) 1974-09-30
SE398834B (sv) 1978-01-23
ATA292373A (de) 1976-05-15
DE2316526B2 (de) 1977-09-08
CH576317A5 (hu) 1976-06-15
JPS519199B2 (hu) 1976-03-24
FR2179007B1 (hu) 1978-07-13
AT334841B (de) 1976-02-10
GB1389803A (en) 1975-04-09
CA971058A (en) 1975-07-15

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