US3754396A - Impacting device - Google Patents

Impacting device Download PDF

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Publication number
US3754396A
US3754396A US00086467A US3754396DA US3754396A US 3754396 A US3754396 A US 3754396A US 00086467 A US00086467 A US 00086467A US 3754396D A US3754396D A US 3754396DA US 3754396 A US3754396 A US 3754396A
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US
United States
Prior art keywords
piston
drive
hammer
cylinder
chamber
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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 - Lifetime
Application number
US00086467A
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English (en)
Inventor
E Erma
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Atlas Copco AB
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Atlas Copco AB
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Publication date
Application filed by Atlas Copco AB filed Critical Atlas Copco AB
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Classifications

    • 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
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B1/00—Percussion drilling
    • E21B1/12—Percussion drilling with a reciprocating impulse member
    • E21B1/24—Percussion drilling with a reciprocating impulse member the impulse member being a piston driven directly by fluid pressure
    • E21B1/30—Percussion drilling with a reciprocating impulse member the impulse member being a piston driven directly by fluid pressure by air, steam or gas pressure

Definitions

  • the impacting device is primarily intended for rock drills and consists of a drive piston, a hammer piston and an auxiliary piston, wherein the drive piston drives the hammer piston by means of an elastic fluid cushion.
  • the powertransmitting fluid cushion obtains a very high working pressure by being fed with elastic fluid under pressure and by being compressed by the drive piston during its working stroke.
  • the auxiliary piston stops the hammer piston during its return stroke by absorbing the kinetic energy of the hammer piston.
  • the hammer piston is stopped in a predetermined position corresponding to the optimum energy output before the succeeding stroke.
  • This invention relates to an impacting device for instance for rock drills, comprising a housing wherein a drive piston and a hammer piston, driven by the drive piston, are reciprocably guided.
  • the invention intends to provide a reciprocating motor, having a great driving force and high frequency.
  • FIG. 1 shows a longitudinal section of a reciprocating motor according to the invention, which motor is built together with an impacting device, for instance for a rock drill.
  • FIG. 2 shows a longitudinal section of a modified motor built together with an impacting device.
  • FIG. 1 The machine shown in FIG. 1 is constructed in accordance with the invention and is intended for rock drilling and the like. It consists of two main parts, namely a pressure fluid driven motor 1 and and impacting device 2 both of which are located within a common housing 3.
  • the motor 1 consists of a cylinder 4 in which a piston 5 is reciprocably guided.
  • the piston is thin walled and defines a chamber 6.
  • This chamber 6 is supplied with the driving fluid of the motor from a pressure fluid source.
  • the driving fluid is gaseous and consists preferably of air. (To simplify the terminology the machine will be described in the following with air as driving medium).
  • the piston and cylinder walls are provided with openings 13 and 14-17 respectively and distributing channels 18-19.
  • the cylinder 4 is also provided with exhaust openings 20-21. These openings are covered and uncovered by the piston 5 during its movement in the cylinder, so that pressurized air, via the distributing channels, always is distributed to the proper side of the piston to reciprocate it in the cylinder.
  • pressurized air via the distributing channels, always is distributed to the proper side of the piston to reciprocate it in the cylinder.
  • the drawing there is shown only one of each of the openings and the distributing channels, but there is in fact a number of them distributed over the piston and the cylinder circumferences.
  • the front edge of the piston covers the exhaust opening 20. Then the openings 13 and register with each other so that pressurized air can flow from the chamber 6 within the piston, through the distributing channel 18 and the opening 14 into the chamber 12a. The chamber 12a is thus pressurized. Subsequently the front edge of the piston covers the opening 14 sealing the chamber 12a. An air cushion by means of which the piston is being slowed down, thus is entrapped in this chamber. The air cushion is then compressed. Owing to the elasticity of air, the air cushion has now an inherent expansion power which recoils the piston in the opposite direction. Thus, the piston 5 is recoiled at its end position by means of an air cushion with a velocity in the opposite direction.
  • the piston 5 As the piston 5 is reciprocated by means of the air cushions, the stresses within the piston are considerably reduced. That means that the piston can be made with thin walls and be comparatively light. Consequently the piston can be made with a large cross sectional area without increasing the piston weight.
  • the piston may preferably be made of a light metal alloy. Owing to the low piston weight and to the fact that the piston recoiled by means of air cushions at the end positions, the motor can be working with a very high frequency. Another factor which has a determining influence on the frequency, is the chamber within the piston, which will serve as a surge chamber, one problem in increasing the frequency or impacting rate of a motor of this type is to feed the cylinder chambers with driving fluid at a sufi'iciently high rate of speed.
  • This fluid must have a very high velocity during a very short period of time.
  • the conduit supplying the motor with pressure fluid cannot, for practical reasons, have a cross-sectional area that is large enough to permit such a high speed there must be fitted a surge chamber to smooth out the intermittent fluid flow.
  • the power output of the motor can be very high and because thereof the motor is especially suitable for driving the impacting device hereinafter described.
  • the impacting device 2 consists of a hammer piston 22, a drive piston 23 intended for driving the hammer piston and an auxiliary piston 24.
  • the drive piston 23 is being constituted by the end part 8 of the motor piston 5.
  • the drive piston 23 drives the hammer piston 22 by means of an air cushion, enclosed within a drive chamber 25 between the two pistons.
  • This drive chamber 25 is fed with pressurized air through an inlet opening 26 which is uncovered by the drive piston in its upper end position. In this position the drive piston is spaced the largest distance from the hammer piston.
  • the drive piston covers the inlet opening 26 to define a closed chamber.
  • the impacting device 2 is provided with an annular auxiliary piston 24 surrounding the hammer piston 22 as a sleeve.
  • the auxiliary piston 24 is in one end provided with an annular flange 27 cooperating with a flange 28 on the hammer piston.
  • the object of the auxiliary piston 24 is to limit the return stroke of the hammer piston and to stop the hammer piston at a predetermined distance from the drive piston irrespective of the recoil energy produced by the drill steel.
  • the kinetic enerby of the hammer piston is absorbed by the auxiliary piston as the flanges 27 and 28 hit each other and the hammer piston is stopped in the predetermined position.
  • this position is critical with respect to the total impact enerby output, it is important that the hammer piston always remains in this position before the succeeding stroke.
  • the weight of the auxiliary piston should be about 40 percent higher than that of the hammer piston to make sure that the hammer piston will stand still after hitting the auxiliary piston.
  • the auxiliary piston 24 is kept in its rest position against the lower end wall 29 of the machine by pressurized air acting upon the upper end surface of the auxiliary piston. Pressurized air leaks through a clearance space between the hammer piston 22 and the housing 4 into a chamber 30 located above the auxil iary piston 24 and acts upon the upper end surface of the auxiliary piston. The space between the lower end surface of the auxiliary piston and the end wall 29 of the housing communicates with the atmosphere.
  • the hammer piston 22 As the hammer piston 22 is driven downwardly by the drive piston 23 the following is happening.
  • the hammer piston moves downwardly until it hits the drill steel neck (not shown). Then the hammer piston changes direction by means of the drill steel recoil on one hand and the compressed air cushion in the chamber 31 on the other hand.
  • a considerable amount of the recoil energy of the hammer piston 22 is transmitted to the drive piston by means of the air cushion in the drive chamber 25.
  • the hammer piston When the hammer piston reaches its upper direction changing position the flange 28 of the hammer piston hits the flange 27 of the auxiliary piston so that the remaining kinetic energy of the hammer piston is transmitted to the auxiliary piston.
  • the hammer piston is thereby stopped in the predetermined position while the auxiliary piston starts to move upwardly towards the drive piston 23.
  • the auxiliary piston is retarded and returned to its rest position by means of the air cushion in the drive chamber 30.
  • the impacting device works with a short stroke at a high frequency and performs a high impact energy output per stroke while the fatigue stresses in the drill steel are low. Fixing the start position of the hammer piston before every working stroke the auxiliary piston arrangement is also advantageous in obtaining a high total impact energy output per time unit.
  • FIG. 2 shows another embodiment of the invention.
  • the machine shown is constructed with special object of reducing its length.
  • the hammer piston has been placed within the motor piston.
  • the motor piston is annular and surrounds the hammer piston.
  • the manner of operation of this machine corresponds mainly with the above described machine.
  • the motor consists of a housing 101, an annular cylinder chamber 102 located within the housing and an annular piston 103 reciprocably guided in the cylinder chamber.
  • an annular chamber 104 which communicates with a pressurized air source by means of an opening 105 in the inner wall of the piston and channels 106, 107 in the housing.
  • the conduit leading from the pressurized air source is connected to the machine by means of a nipple 108.
  • the piston 103 and the housing 101 are provided with openings 109 and 110-113 resp. and the housing is also provided with distributing channels 114-115 for distributing pressurized air to chambers at the ends of the piston causing its reciprocating movement. Futhermore, the housing 101 is provided with two exhaust openings 116 and 116".
  • the opening 109 in the piston wall is covered by the cylinder wall and the exhaust opening 116 is uncovered by the upper edge of the piston so that the pressurized air within the cylinder chamber may escape into the atmosphere.
  • a corresponding procedure occurs at the other end position of the piston 103.
  • the impacting device consists of a hammer piston 117, a drive piston 118 and an auxiliary piston 1 19.
  • the drive piston drives the hammer piston by means of an air cushion.
  • the drive piston 118 is constituted by a flange provided at the inner wall of the motor piston 103.
  • the flange, as well as the motor piston, is annular and surrounds the hammer piston.
  • the later is also provided with an annular flange 120 which cooperates with the drive piston l 18.
  • the drive piston 118 and the flange 120 enclose an annular dn've chamber 121 in which a high pressure air cushion transmits driving drive chamber 121 constitutes a pressure riser as the drive piston compresses the enclosed air volume during its working stroke.
  • the drive piston 118 drives the hammer piston 117 downwardly in FIG. 2 by means of the powertransmitting air cushion.
  • the hammer piston is driving downwardly towards a drill steel neck to deliver a blow thereon.
  • a return movement is imparted to the hammer piston.
  • the main part of the recoil energy of the hammer piston is transmitted to the drive piston by means of the air cushion within the chamber 121.
  • the machine is provided with an auxiliary piston 119.
  • the auxiliary piston is located at the rear end of the machine, the upper end in FIG. 2, and as it is hit by the rear end of the hammer piston it tends to to absorb the kinetic energy of the hammer piston and stop it at a predetermined distance from the drive piston. After that, the auxiliary piston gains some speed, which is retarded by the action of the pressurized air from the pressurized air source. This pressurized air acts continuously on the upper end of the auxiliary piston and returns the auxiliary piston to its rest position.
  • the impacting devices according to the invention can be fitted with suitable drill steel chuck and drill steel rotation mechanism. What I claim is:
  • An impacting device comprising:
  • inlet means associated with said cylinder for admitting an elastic pressure fluid into said drive chamber
  • auxiliary piston reciprocatably disposed in said cylinder and accommodating said hammer piston for reciprocating movement therein;
  • h. means associated with said auxiliary piston and said hammer piston effective to transmit the kinetic energy produced by the recoil movement of the hammer piston to said auxiliary piston by impact;
  • said primary cylinder comprising a portion of narrowed diameter
  • said drive piston having a portion of correspondingly reduced diameter forslidable engagement with said portion, said drive chamber being located within said narrowed portion of the primary cylinder at the narrowed end of the drive piston.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Earth Drilling (AREA)
US00086467A 1969-11-07 1970-11-03 Impacting device Expired - Lifetime US3754396A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE15297/69A SE343784B (no) 1969-11-07 1969-11-07

Publications (1)

Publication Number Publication Date
US3754396A true US3754396A (en) 1973-08-28

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00086467A Expired - Lifetime US3754396A (en) 1969-11-07 1970-11-03 Impacting device

Country Status (7)

Country Link
US (1) US3754396A (no)
JP (1) JPS5116881B1 (no)
AT (1) AT308030B (no)
CA (1) CA937468A (no)
GB (1) GB1325499A (no)
SE (1) SE343784B (no)
ZA (1) ZA707292B (no)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4945815A (en) * 1988-05-25 1990-08-07 Industrial Technology Research Institute Pneumatic type of reciprocating movement device
US20090114409A1 (en) * 2007-11-06 2009-05-07 Duval Maurice Pneumatic impact tool
US9151386B2 (en) 2013-03-15 2015-10-06 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US9555531B2 (en) 2013-03-15 2017-01-31 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston
US9592598B2 (en) 2013-03-15 2017-03-14 Caterpillar Inc. Hydraulic hammer having impact system subassembly
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

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2551303C3 (de) * 1975-11-14 1981-04-02 Institut gornogo dela Sibirskogo otdelenija Akademii Nauk SSSR, Novosibirsk Druckluftbetriebene Tiefloch-Schlagbohrmaschine
SE424830B (sv) * 1978-01-12 1982-08-16 Goran Alfred Nilsson Anordning for forlengning av kraftpulsforloppet hos anslagsmassan vid me slagverkan arbetande verktyg
AUPN751396A0 (en) * 1996-01-12 1996-02-08 Russell Mineral Equipment Pty Ltd Linerbolt removing tool (lrt)
US7878265B2 (en) 2007-02-06 2011-02-01 Makita Corporation Impact power tool

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US543052A (en) * 1895-07-23 Frank c
US891831A (en) * 1908-01-22 1908-06-30 Joseph Frederick Pneumatic hammer.
US1346166A (en) * 1919-12-09 1920-07-13 Bernhard Jakob Pneumatic hammer
US1461460A (en) * 1920-06-10 1923-07-10 Jr Robert C Schroth Power hammer
US1827877A (en) * 1929-03-06 1931-10-20 John H Meeker Power hammer
US2075235A (en) * 1933-02-06 1937-03-30 Sciaky David Hydraulic press and similar apparatus
DE734207C (de) * 1941-08-03 1943-04-10 Frankfurter Maschb Ag Vorm Pok Rueckstossdaempfeinrichtung
US3140586A (en) * 1960-09-19 1964-07-14 Joelson Karl-Evert Anders Hydraulically operated apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US543052A (en) * 1895-07-23 Frank c
US891831A (en) * 1908-01-22 1908-06-30 Joseph Frederick Pneumatic hammer.
US1346166A (en) * 1919-12-09 1920-07-13 Bernhard Jakob Pneumatic hammer
US1461460A (en) * 1920-06-10 1923-07-10 Jr Robert C Schroth Power hammer
US1827877A (en) * 1929-03-06 1931-10-20 John H Meeker Power hammer
US2075235A (en) * 1933-02-06 1937-03-30 Sciaky David Hydraulic press and similar apparatus
DE734207C (de) * 1941-08-03 1943-04-10 Frankfurter Maschb Ag Vorm Pok Rueckstossdaempfeinrichtung
US3140586A (en) * 1960-09-19 1964-07-14 Joelson Karl-Evert Anders Hydraulically operated apparatus

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4945815A (en) * 1988-05-25 1990-08-07 Industrial Technology Research Institute Pneumatic type of reciprocating movement device
US20090114409A1 (en) * 2007-11-06 2009-05-07 Duval Maurice Pneumatic impact tool
US7681658B2 (en) * 2007-11-06 2010-03-23 Maurice DUVAL Pneumatic impact tool
US9151386B2 (en) 2013-03-15 2015-10-06 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US20160025112A1 (en) * 2013-03-15 2016-01-28 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US9555531B2 (en) 2013-03-15 2017-01-31 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston
US9592598B2 (en) 2013-03-15 2017-03-14 Caterpillar Inc. Hydraulic hammer having impact system subassembly
US9822802B2 (en) * 2013-03-15 2017-11-21 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US10562166B2 (en) 2013-03-15 2020-02-18 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston
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
SE343784B (no) 1972-03-20
JPS5116881B1 (no) 1976-05-28
AT308030B (de) 1973-06-25
DE2053335A1 (de) 1971-09-16
CA937468A (en) 1973-11-27
ZA707292B (en) 1971-08-25
GB1325499A (en) 1973-08-01

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