US3821992A - Impact device using a gas as its medium - Google Patents

Impact device using a gas as its medium Download PDF

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Publication number
US3821992A
US3821992A US00286730A US28673072A US3821992A US 3821992 A US3821992 A US 3821992A US 00286730 A US00286730 A US 00286730A US 28673072 A US28673072 A US 28673072A US 3821992 A US3821992 A US 3821992A
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piston
air
impact
chamber
pump
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US00286730A
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S Matsuo
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D9/00—Portable percussive tools with fluid-pressure drive, i.e. driven directly by fluids, e.g. having several percussive tool bits operated simultaneously
    • B25D9/06—Means for driving the impulse member
    • B25D9/08—Means for driving the impulse member comprising a built-in air compressor, i.e. the tool being driven by air pressure

Definitions

  • the air pump and the impact cylinder are respectively divided by a pump piston and a hammer piston into upper and lower chambers which intercommunicate upper with upper and lower with lower through valves which regulate the flow of high and negative pressure gas causing the downward impact stroke of the hammer piston onto the tool at the lower end of the impact cylinder and the .downward'stroke of the pump piston to begin simultaneously after the pump piston has reached its top dead point compressing the air in the upper chamher to the maximum and generating the maximum negative pressure in the lower chamber.
  • this pneumatic breaker which releases the used air into the atmosphere during each rotation is very low in mechanical efficiency owing to the mechanical loss of the air compressor, the mechanical loss of the impact device of the breaker, the heat loss at both the compressor and the impact device andthe friction at the inside of the hose.
  • the hose is constantly being dragged over the ground and is sometimes even pulled tense by the movement of the operation truck. Also the hose is run over by the heavy dump car carrying the stones for crushing. Because of fast wear and troublesome handling the hose becomes one of the weak points of the operation.
  • the present invention provides an impact device characterized by selecting the number of hammer piston cycles per minute according to the nature and purpose of the operation, sealing the positive and negative pressures in the air pump by closing the respective valves until the air pump finishes compressing the operatingair so that the heavy hammer piston is held in the starting position at the upper dead point until its impact stroke is started, opening the pair of valves much as an air rifle is triggered as soon as the compression has reached its limit, giving a powerful assistance to the downward impact stroke of the hammer piston by injecting high pressure air into the upper chamber of the hammer piston and applying negative pressure to the lower chamber, properly adjusting the time required for the upward retum stroke of the hammer piston to a half of the cycle time of the air pump, while that for the downward impact stroke is only a small fraction of the cycle time of the driving pump, mounting both the driving pump and the impact device on the operation truck so that the driving pump can ob tain sufficient driving power from the engine
  • A is an air pump whose cylinder 1 contains 7 piston 2 which divides its interior into upper chamber la and a lower chamber 1b. When one of the chambers increases in volume by the motion of the piston 2, the other decreases in volume.
  • Below cylinder 1 and connected thereto is cylinder 3 of the piston-cylinder type hydraulic actuator B which causes piston 2 of air pump A to make regular reciprocal strokes.
  • Piston 4 within cylinder 3 is connected to piston 2 of air pump A by rod 5.
  • the inside of cylinder 3 is likewise partitioned by piston 4 into upper chamber 3a and lower chamber 3b, one increasing its volume when the other decreases its volume.
  • Shaft 6a and 6b are pivotally mounted through the wall of cylinder 3 at its top and bottom and the respective inner ends of these shafts are provided with arms 7a and 7b positioned inside the upper and lower chambers 3a and 3b and at their respective outer ends thereof are provided the outer arms 8a and 8b.
  • Said outer arms 8a and 8b change over the operation of spool 9 of the spool type change-over valve C attached to the outside of cylinder 3 in the following way.
  • Change-over valve C has one port P for introducing the input liquid pressure from a hydraulic (e.g. oil hydraulic) pump and two ports T, and T for returning it to the tank.
  • a hydraulic e.g. oil hydraulic
  • T for returning it to the tank.
  • arms 7a and 7b when piston 4 acts on one of them and brings spool 9 to the other position by means of the outer arm, the other of them is returned to the ready position by spool
  • the input liquid pressure is produced by a hydraulic pump driven by the power taken from the operation truck.
  • hydraulic actuator B causes piston 4 to make regular reciprocating impact strokes by means of change-over valve C and drives piston 2 of air pump A through rod 5.
  • Opening 10 communicates with exhaust valve 12 of cylinder head 1' through passage 11.
  • This opening 10 may be branched into upper and lower parts as shown as 10a and 10b in FIG. 4.
  • Exhaust valve 12 opens both when strong positive pressure enters passage 11 because of the compression of the air in lower chamber 1b by piston 2 and when piston 2 has reached the top dead point by raising lower end of stem 12' protruding into upper chamber 1a.
  • Cylinder head 1' is provided not only with exhaust valve 12 but also with intake valve 14 which has opening 13 of the head as its seat. Opening 13 is connected through the intake valve 14 and tube 15 to opening 18 at the top of upper chamber 17a of impact cylinder 17 of the impact section containing hammer piston 16.
  • Intake valve 14 opens both when strong negative pressure is created in upper chamber 1a by the downward stroke of piston 2 as described later and when piston 2 has reached the top dead point in cylinder 1 stem 14 in pushed down by rocker arm 20 operated by the raised tappet.
  • Impact cylinder 17 is provided at a lower portion on its inside with upper and lower openings 21 and 22 con necting to each other at the branching point below passage 23, one of said openings being opened above the hammer piston into upper chamber 17a and the other being closed by the side of the hammer piston when hammer piston 16 reaches the bottom dead point.
  • the respective vertical positions of said upper and lower openings 21 and 22 are so selected that when hammer piston 16 makes its downward impact stroke upper opening 21 is first closed by the side of the piston and then lower opening 22 is also closed and when the pis-- ton reaches the bottom dead point upper opening 21 is opened into upper chamber 17a but the lower opening 22 remains closed by the piston.
  • openings 21 and 22 may be prepared as one long axial opening as far as said relationship is maintained.
  • Passage 23 which is connected to upper and lower openings 21 and 22 communicates with exhaust valve 12 mounted on the head of the air pump cylinder by means of tube 24 and is further connected to the opening 10 through the passage 11.
  • Impact cylinder 17 is provided at its lower end with tool 25 for striking the object to be crushed when hammer piston 16 makes its downward impact stroke and reaches the bottom dead point.
  • This tool 25 is returned to its elevated position by a spring 26 or the like in a known way and has its upper end thrust back into the lower chamber of the impact cylinder.
  • Hammer piston 16 is also provided at its upper end with stopper 27 planted therein.
  • stopper 27 planted therein.
  • air of atmospheric pressure is sealed into the system for the total volume (working volume plus clearance volume) of airpump A and for the volumes of upper and lower chambers 17a and 17b of the impact section.
  • this air is converted into a gas containing no oxygen similar to the exhaust gas of an internal combustion engine because the oxygen consumed in an explosive reaction with a relatively inflammable gas resulting from the decomposition of the lubricant at the stroke end of the hammer piston in the early stages of the operation.
  • an inert gas may be sealed into the system instead of air.
  • the ratio of the cubic capacity of air pump to the total stroke cubic capacity of hammer piston 16 is generally calculated by the total power required.
  • the equipment of the present invention is designed with a large cubic capacity ratio of 1.4 to 1.8 in order to allow hammer piston 16 to make an effective uniform motion with a surplus volume of air always equal to the difference between the two cubic capacities.
  • the most effective ratio of surplus air is selected by the cycle time which is determined by the horsepower of power source and the weight and stroke of the hammer piston, depending on the nature of work. Then, as shown in FIG.
  • the air pump A, hydraulic actuator B and change-over valve C are installed in swing arm 28 of the operation truck, and impact section D is fixed to the end of swing arm 28 by means of articulated connecting rods so that the tool can be faced in the desired direction by moving vertically with the help of position controlling actuator 28'.
  • tubes and 24 should be flexible and as short as possible within the limit necessary for allowing the vertical motion of impact section D.
  • FIG. 4a-4f The movement of air and change of pressure in one cycle of this invention will be explained below by referring to FIG. 4a-4f.
  • piston 2 of air pump A approaches the end of the downward stroke (FIG. 4a)
  • great negative pressure develops in upper chamber la.
  • intake valve 14 is opened by this negative pres sure to connect upper chamber 17a of impact section D to said upper chamber 1a through tube 15 and opening 18.
  • the air compressed in lower chamber lb of the pump opens exhaust valve 12 through the opening 10 and the passage 11 and operates as positive pressure in lower chamber 17b of impact section I) after passing through tube 24, passage 23 and openings 21 and 22.
  • hammer piston 16 makes an upward re- .turn stroke sucked by the negative pressure from above and pushed up by the positive pressure from below, and then closes the opening 18 with stopper 27 (FIG. 4b).
  • lower chamber 17b of the impact section forms a cushion chamber which cushions the hammer piston at the bottom dead point with the help of the counteraction of tool 25.
  • upper open ing 21 opens for a moment above piston 16 and connects upper chamber 17a of the impact section to the port 23. Therefore, the high pressure gas inside upper chamber flows into passage 23 with a strong moment of inertia owing to the multiplied effect of the violent downward flow communicating with the negative pressure zone inside the passage 23, the difference between the two pressures and the great volume of operating gas in the air pump.
  • FIG. 5 is a diagram illustrating the relationship between the cycle time and stroke for the air pump piston and hammer piston of the present invention.
  • Air pump piston 2 shown by solid line opens the exhaust and intake valves 12 and 14 after completing its air compressing action in upper chamber 1a and its negative pres sure generating action in lower chamber lb by rising from bottom dead point BP and reaching top dead point TP.
  • hammer piston 16 is sucked into lower chamber 17b by strong negative pressure and makes a downward impact stroke to reach the bottom dead point HP subjected to the injection of the air compressed into upper chamber la by the air pump piston, while the air pump piston makes a downward stroke toward the bottom dead point BP at a given speed.
  • Hammer piston 16 which has reached the bottom dead point HP changes the pressure in the upper chamber of the impact section from positive to negative before the air pump piston reaches bottom dead point BP and then returns to top dead point l-ITP'by the positive: pressure generated in the lower chamber of the air pump. While the air pump piston is making its upward stroke the hammer piston stays at the position HTP.
  • the pump piston and hammer piston start their respective downward strokes simultaneously.
  • the pump piston makes uniform motion and the hammer piston makes extremely ununiform motion including a stop at the top dead point, though both motions are efv 7 fected regularly.
  • the pump piston is making its downward stroke the hammer piston completes its momentary downward impact stroke and its upward return stroke.
  • the exhaust and intake valves 12 and 14 are so designed that they are opened when the pump piston has reaches the top dead point and when the pump piston has madeits downward stroke to generated strong pressures in the upper and lower chambers.
  • these valves may also be designed so that they are opened when the pump piston has reached the top dead point, and lead valves or the like may be additionally installed with both valves, said additional valves being opened by the pressures generated in the chambers.
  • suction valve 14, tappet 19 and rocket arm 20 as shown in FIG. 6 and install, for example, a solenoid-operated valve or bydraulically operated valve 29 incorporating a spring directly above the position of opening 18 into which stopper 27 is thrust, said valve 29 being opened when the pump piston is making a downward stroke, closed when the pump piston reaches the bottom dead point, also closed when the pump piston is making an 'upward stroke and opened again when the pump piston is about to make downward stroke after reaching the top dead point.
  • the total volume of tube 15 is designed as the clearance volume of air pump A.
  • Valve 29 shown in FIG. 6 is usually closed by the spring 29.
  • spool 9 of change-over valve C is switched over to the lower position so that the pump piston can make a downward stroke after reaching the top dead point and part of the liquid pressure introduced into the upper chamber of the pump piston through passage P is led into the valve through branched passage 30 in order to let the liquid 8.
  • this valve 29 may be used in place of exhaust valve 12 in such a way that it is kept open by liquid pressure while the pump piston is making a downward stroke and closed by spring 29' while the pump piston is making an upward stroke.
  • the greater the entire design the greater area the hammer piston requires because of the ratio between its width and depth. But a large output may be obtained at will by making the hammer piston hollow.
  • the hammer piston 16 At the each start of operation, the hammer piston 16 is at the bottom dead point and blocks lower opening 22 with its side. So it is impossible to have the positive pressure generated in the lower chamber of air pump A act on the hammer piston from below. For this reason, the negative pressure generated in the upper chamberof air pump is used at the start. This means that it takes time for the hammer piston to start making regular strokes. In actual operation, however, this time may be shortened by providing suction valve 31 at the lower end of lower chamber 17b of the impact section by making a suitable opening there and connecting this valve 31 to passage 23 so that the positive pressure generated in the lower chamber 1b of the air pump can act on the hammer piston from below even if it blocks lower opening 22. Of course, this valve 31 is closed when hammer piston 16 makes a downward impact stroke and compresses the air in lower chamber 1712. Therefore, valve 31 does not interfer with the cushioning of the hammer piston at the bottom dead point.
  • Air pump A of the illustrated embodiment is shown as operated by hydraulic reciprocating actuator B.
  • this actuator may be a rotary motor reciprocally driven, for example, by the rod 5 by means of a crank through a link.
  • the power source for operating air pump A may be oil pressure obtained from the hydraulic pump driven by the engine of the operation truck. In this case, while the power is being used for running the truck the hydraulic pump is stopped by disengaging the clutch and when the truck is stopped the pump is operated by engaging the clutch.
  • An impact device using gas as its medium which comprises in combination,
  • A. an air pump having an upper and a lower chamher, a movable piston intermediate the upper and lower chamber, an air communication port between the upper and lower chambers, and a piston rod joining the movable piston and projecting through a wall of the lower chamber, said piston rod having disposed thereon a second piston within a hydraulic pump, said hydraulic pump providing drive means for effecting upward and downward strokes of said movable piston at a fixed speed;
  • an impact section consisting of an impact cylinder having an upper and a lower chamber, a hammer piston having a projecting member disposed along an upper surface and means for striking a tool by an opposite surface, a tool projecting from the impact section;

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
US00286730A 1971-09-23 1972-09-06 Impact device using a gas as its medium Expired - Lifetime US3821992A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46073805A JPS519938B2 (ru) 1971-09-23 1971-09-23

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US3821992A true US3821992A (en) 1974-07-02

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US00286730A Expired - Lifetime US3821992A (en) 1971-09-23 1972-09-06 Impact device using a gas as its medium

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US (1) US3821992A (ru)
JP (1) JPS519938B2 (ru)
AT (1) AT334840B (ru)
CA (1) CA971059A (ru)
CH (1) CH565629A5 (ru)
DE (1) DE2246370C3 (ru)
FR (1) FR2154232A5 (ru)
GB (1) GB1361552A (ru)
IT (1) IT969434B (ru)
SE (1) SE398719B (ru)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4290489A (en) * 1974-12-18 1981-09-22 Charles Leavell Vibrationless pneumatic tools
US4690225A (en) * 1979-05-14 1987-09-01 Institut Gornogo Dela Sibirskogo Otdelenia Akademii Nauk Sssr Percussive tool
US4964473A (en) * 1988-03-15 1990-10-23 Ihc Holland N.V. Method for driving a hydraulic submerged tool
US20080190988A1 (en) * 2007-02-09 2008-08-14 Christopher Pedicini Fastener Driving Apparatus
WO2009074383A1 (de) * 2007-12-12 2009-06-18 Robert Bosch Gmbh Handwerkzeugmaschinenschlagwerkeinheit
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
US8079504B1 (en) * 2010-11-04 2011-12-20 Tricord Solutions, Inc. Fastener driving apparatus
US20120286014A1 (en) * 2011-05-11 2012-11-15 Christopher Pedicini 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
US20160340849A1 (en) * 2015-05-18 2016-11-24 M-B-W, Inc. Vibration isolator for a pneumatic pole or backfill tamper
US9844865B2 (en) 2012-04-09 2017-12-19 Makita Corporation Driver tool
US9943952B2 (en) 2013-12-11 2018-04-17 Makita Corporation Driving tool
CN108656027A (zh) * 2017-03-28 2018-10-16 南京德朔实业有限公司 钉枪
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
US11110577B2 (en) 2017-11-16 2021-09-07 Milwaukee Electric Tool Corporation Pneumatic fastener driver

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2126940B (en) * 1982-09-04 1986-02-26 Inst Gornogo Dela Sibirskogo O Percussive tool
DE4128137A1 (de) * 1991-08-24 1993-02-25 Krupp Maschinentechnik Sicherheitseinrichtung fuer fluidbetriebene schlagwerke
DE10028555C1 (de) * 2000-06-09 2001-09-13 Hilti Ag Diffusor-Einspritzdüse zum Einspritzen von flüssigem Brenngas bei einem Arbeitsgerät
JP4648974B2 (ja) 2006-04-13 2011-03-09 株式会社テムコジャパン アンテナ付きハンドマイクのケーブルを携帯無線機本体へ接続するためのコネクタ
DE102009051089B4 (de) * 2009-10-28 2017-12-07 Rosink-Werkstätten GmbH Schlagzylinder

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US819011A (en) * 1905-12-15 1906-04-24 Ingersoll Rand Co Electropneumatic channeler.
US942163A (en) * 1909-12-07 August Berner Pneumatic power-hammer.
US1071387A (en) * 1912-10-05 1913-08-26 Hans Charles Behr Percussive apparatus.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US942163A (en) * 1909-12-07 August Berner Pneumatic power-hammer.
US819011A (en) * 1905-12-15 1906-04-24 Ingersoll Rand Co Electropneumatic channeler.
US1071387A (en) * 1912-10-05 1913-08-26 Hans Charles Behr Percussive apparatus.

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4290489A (en) * 1974-12-18 1981-09-22 Charles Leavell Vibrationless pneumatic tools
US4690225A (en) * 1979-05-14 1987-09-01 Institut Gornogo Dela Sibirskogo Otdelenia Akademii Nauk Sssr Percussive tool
US4964473A (en) * 1988-03-15 1990-10-23 Ihc Holland N.V. Method for driving a hydraulic submerged tool
US20080190988A1 (en) * 2007-02-09 2008-08-14 Christopher Pedicini Fastener Driving Apparatus
US8875969B2 (en) * 2007-02-09 2014-11-04 Tricord Solutions, Inc. Fastener driving apparatus
WO2009074383A1 (de) * 2007-12-12 2009-06-18 Robert Bosch Gmbh Handwerkzeugmaschinenschlagwerkeinheit
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
USRE44001E1 (en) * 2009-02-25 2013-02-19 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
US8800834B2 (en) * 2011-05-11 2014-08-12 Tricord Solutions, Inc. Fastener driving apparatus
US20120286014A1 (en) * 2011-05-11 2012-11-15 Christopher Pedicini Fastener Driving Apparatus
US20150129630A1 (en) * 2012-04-09 2015-05-14 Makita Corporation Driver Tool
US9827659B2 (en) * 2012-04-09 2017-11-28 Makita Corporation Driver tool
US9844865B2 (en) 2012-04-09 2017-12-19 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
US20160340849A1 (en) * 2015-05-18 2016-11-24 M-B-W, Inc. Vibration isolator for a pneumatic pole or backfill tamper
US10781566B2 (en) 2015-05-18 2020-09-22 M-B-W, Inc. Percussion mechanism for a pneumatic pole or backfill tamper
CN108656027A (zh) * 2017-03-28 2018-10-16 南京德朔实业有限公司 钉枪
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

Also Published As

Publication number Publication date
DE2246370B2 (de) 1977-10-20
JPS4844871A (ru) 1973-06-27
IT969434B (it) 1974-03-30
AT334840B (de) 1976-02-10
DE2246370C3 (de) 1978-06-08
FR2154232A5 (ru) 1973-05-04
ATA818272A (de) 1976-05-15
CA971059A (en) 1975-07-15
JPS519938B2 (ru) 1976-03-31
CH565629A5 (ru) 1975-08-29
GB1361552A (en) 1974-07-24
DE2246370A1 (de) 1973-03-29
SE398719B (sv) 1978-01-16

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