GB2141659A - Tool retainer for a percussive tool - Google Patents

Tool retainer for a percussive tool Download PDF

Info

Publication number
GB2141659A
GB2141659A GB08414260A GB8414260A GB2141659A GB 2141659 A GB2141659 A GB 2141659A GB 08414260 A GB08414260 A GB 08414260A GB 8414260 A GB8414260 A GB 8414260A GB 2141659 A GB2141659 A GB 2141659A
Authority
GB
United Kingdom
Prior art keywords
tool
sleeve
bushing
retainer
axis
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.)
Granted
Application number
GB08414260A
Other versions
GB8414260D0 (en
GB2141659B (en
Inventor
Ivan Andreevich Prokhorov
Sergei Anatolievic Sapozhnikov
Vladimir Porfirievich Balandin
Jury Nikitovich Kolgan
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.)
VNII PK I MECHANIZIROVANNOGO
Original Assignee
VNII PK I MECHANIZIROVANNOGO
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 VNII PK I MECHANIZIROVANNOGO filed Critical VNII PK I MECHANIZIROVANNOGO
Publication of GB8414260D0 publication Critical patent/GB8414260D0/en
Publication of GB2141659A publication Critical patent/GB2141659A/en
Application granted granted Critical
Publication of GB2141659B publication Critical patent/GB2141659B/en
Expired legal-status Critical Current

Links

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
    • B25D17/08—Means for retaining and guiding the tool bit, e.g. chucks allowing axial oscillation of the tool bit
    • B25D17/084—Rotating chucks or sockets
    • B25D17/088—Rotating chucks or sockets with radial movable locking elements co-operating with bit shafts specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
    • B23B31/02—Chucks
    • B23B31/10—Chucks characterised by the retaining or gripping devices or their immediate operating means
    • B23B31/107—Retention by laterally-acting detents, e.g. pins, screws, wedges; Retention by loose elements, e.g. balls
    • B23B31/1072—Retention by axially or circumferentially oriented cylindrical elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
    • B23B31/02—Chucks
    • B23B31/10—Chucks characterised by the retaining or gripping devices or their immediate operating means
    • B23B31/107—Retention by laterally-acting detents, e.g. pins, screws, wedges; Retention by loose elements, e.g. balls
    • B23B31/10741—Retention by substantially radially oriented pins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D2217/003—Details relating to chucks with radially movable locking elements
    • B25D2217/0038—Locking members of special shape
    • B25D2217/0049—Roll-shaped locking members

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Securing Of Glass Panes Or The Like (AREA)

Abstract

A tool retainer for a percussive tool comprises a bushing (1) for receiving a shank (2) of a working tool (3) having at least one guide recess (7) extending at right angle to its axis in which is installed a cylindrical retainer member (8), a sleeve (5) installed for axial reciprocations on the bushing (1) having at least a pair of guide holes (20) each receiving a respective end of the cylindrical retainer member (8). The guide holes (20) have portions a extending in parallel with the axis of the sleeve (5) which support the ends of the cylindrical retainer member (8) when the sleeve (5) is in one extreme position and inclined portions (b) extending in the direction away from the axis of the sleeve (5) which support the ends of the cylindrical retainer member (8) when the sleeve (5) is in the second extreme position. The inclined portions (b) extend at an acute angle with respect to the axis of the sleeve (5) in the direction of removal of the working tool (3). <IMAGE>

Description

SPECIFICATION Tool retainer for a percussive tool The invention relates to percussive tools having rotary hammer working tools and deals with tool retainers for retaining working tools in a percussive tool.
The invention may be used in portable percussive tools such as hammer drills or rock drills which are widely used in the construction and mining industries and in performing geological explorations.
Known in the art is a tool retainer for a percussive tool (cf. French patent 2186870 of September 13, 1972, Cl. B 25D 17/00), comprising a bushing for receiving a shank of a working tool, which has at least one recess for receiving a cylindrical retainer member extending at right angle to the bushing axis.
The retainer member retaines the working tool by a part of its periphery which engages the shank of the working tool. One end of the retainer member protrudes outside the bushing. A flat is provided on the cylindrical retainer member. To remove the working tool from the bushing, the flat is positioned in parallel with the shank of the working tool by moving the retainer member along the recess.
In this tool retainer, the protruding portion of the retainer member results in a larger size of the tool retainer and lowers reliability of retaining of the working tool since an accidental contact with foreign objects or mishandling of the percussive tool may result in the retainer member being shifted from its position in which it retains the working tool, and the working tool may fall out of the retainer.
Known in the art is a tool retainer for a percussive tool (cf. French patent No.
2248914 of October 30. 1974, Cl. B 25D 17/28) in which the retainer member is inside the retainer. It comprises a buching for receiving the shank of the working tool, having at least one guide recess, a sleeve mounted on the bushing for axial reciprocations, and a cylindrical retainer member mounted in the guide recess and extending at right angle to the bushing axis, the ends of the retainer member protruding outside the bushing and cooperating with the sleeve during its movement.
In this tool retainer, the guide recess of the bushing is curvilinear.
The bushing size is determined by the dimensions of the retainer member. The guide recess weakens the peripheral portion of the bushing cross-section in the zone of the retainer member when the tool is inserted since radial impact loads taken up by the retainer member when it cooperates with the tool shank are transmitted to the weakened peripheral section of the bushing and may cause its failure. This makes the tool retainer rather unreliable.
At the same time, a small increase in the cross-sectional area of the bushing aimed at lowering specific loads acting thereon would result in longer retainer members, which brings about increased weight and size of the tool retainer which is unacceptable in portable tools.
It is an object of the invention to provide a tool retainer for a percussive tool which is highly reliable.
The invention substantially consists in that in a tool retainer for a percussive tool, comprising a bushing for receiving the shank of a working tool having at reast one guide recess, a sleeve mounted for axial reciprocations on the bushing, a cylindrical retainer member installed in the guide recess of the bushing to extend at right angle to its axis, the ends of the retainer member protruding outside the bushing and engaging the sleeve during its movement, according to the invention, the sleeve has at least a pair of guide holes and a respective end of the cylindrical retainer member is received in each of these guide holes, the guide holes having portions, which extend in parallel with the axis of the sleeve and support the ends of the retainer member when the sleeve is in one extreme position, and inclined portions conjugated therewith and extending in the direction away from the sleeve axis, which support the ends of the retainer member when the sleeve is in the second extreme position, the inclined portions extending at an acute angle to the sleeve axis in the direction of removal of the working tool, the guide recess of the bushing extending at right angle to the axis thereof.
This construction of the tool retainer in a percussive took makes it possible to relieve the cross-section of the bushing owing to the fact that radial impact loads taken up by the cylindrical retainer member are transmitted to the sleeve thereby improving reliability of the tool retainer without any increase in its size.
The invention will now be described with reference to its embodiment illustrated in the accompanying drawings, in which: Figure 1 shows a longitudinal sectional view of a tool retainer for a percussive tool, according to the invention; Figure 2 show a longitudinal sectional view of an embodiment of a sleeve with guide holes, according to the invention; Figure 3 is a transverse sectional view of the tool retainer taken along the line Ill-Ill in Fig. 1, according to the invention; Figure 4 shows a longitudinal sectional view of a tool retainer for a percussive tool, according to the invention, in the position where the working tool is to be removed.
A tool retainer for a percussive tool will be described as applied to a tool retainer for a hammer drill. The tool retainer comprises a bushing 1 (Fig. 1) for receiving a shank 2 of a working tool 3. A boring bit is used as the working tool 3 in hammer drills, and peaks or chisels are used in other percussive tools depending on application. The bushing 1 is secured in a casing 4 of the hammer drill. A sleeve 5 is installed on the bushing 1 for axial reciprocations between two extreme positions.
A precompressed spring 6 is installed between the sleeve 5 and bushing 1. The spring 6 retains the sleeve 5 in its first extreme position by its force.
The bushing 1 has at least one guide recess 7. The guide recess 7 extends at right angle to the axis of the bushing 1. In powerful percussive tools, two guide recesses 7 seem to be more appropriate as shown in the embodiment illustrated herein.
Cylindrical retainer members 8 are installed in the guide recesses 7, the recess 7 being of a width such as to enable free movement of the retainer member 8 therein. Fig. 1 shows the tool retainer of a percussive tool with a hole 9 of the bushing 1 in which the working tool 3 is inserted. The shank 2 of the working tool 3 has a groove 10 of circular section. The cross-section of the retainer members 8 closes the hole 9 of the bushing 1 so as to reduce its diameter. The retainer members 8 engage the shank 2 of the working tool 3 in the zone of its groove 10 thereby retaining the working tool 3 in the tool retainer.
In order to prevent the retainer members 8 from failing out of the sleeve 5, the sleeve is surrounded by an expansion ring 11.
A cover 13 is fixed to the sleeve 5 by means of a retainer ring 12. The shank 2 of the working tool 3 cooperates with a hammer 14 installed in the casing 4 of the percussive tool, and the edge of the working tool engages a workpiece such as concrete 15.
For rotation of the working tool 3, the shank 2 there of is connected to a driven gear 16 which meshes with a drive gear 17 operatively connected to a drive shaft 18 (the drive is not shown in the drawings). The shaft 18 is journalled in the casing 4 by means of a rolling-contact bearing 19.
The sleeve 5 has at least a pair of guide holes 20 (Fig. 2). There are two pairs of the holes 20 in this embodiment. Each hole 20 has a portion "a" extending in parallel with an imaginary axis 21 of the sleeve 5 and an inclined portion b conjugated therewith which extends in the direction away from the axis 21 of the sleeve 5. The inclined portion b extends at an acute angle to the axis 21 of the sleeve 5 in the direction of removal of the working tool which is shown by arrow A in the drawing.
To facilitate manufacture, the sleeve 5 is made composite of two parts 22 and 23 as shown in Fig. 2. One part 22 of the sleeve 5 is made of a metal. In this part 22 of the sleeve 5 there are provided the portions a of the holes 20 which take up the radial loads exerted by the working tool 3. The second part 23 of the sleeve 5 in which are made the inclined portions "b of the holes 20 does not take up impact loads and is only designed for moving the retainer members 8 for removal or insertion of the working tool 3. In order to make the sleeve 5 lighter in weight, this part 23 is preferably made of a plastic.
The ends of the cylindrical retainer members 8 (Fig. 3 protrude outside the bushing 1 and each end is received in the respective hole 20.
Fig. 4 shows the tool retainer in the position when the working tool 3 should be removed from, or inserted into the bushing 1.
The sleeve 5 is in the second extreme position after shifting it along the bushing 1 from its initial position shown in Fig. 1 in the direction opposite to the direction of removal of the working tool 3. The cylindrical retainer members 8 in this position are shifted along the recesses 7 of the bushing 1 radially shifted along the recesses 7 of the bushing 1 radially away from the axis of the bushing 1 so that they do not obstruct the hole 9 of the bushing 1, and the shank 2 of the working tool 3 may be freely removed from, or inserted into the bushing 1.
The working tool 3 is installed in the tool retainer of a percussive tool in the following manner.
All movable elements of the tool retainer-the sleeve 5, spring 6 and retainer members 8 are in the position shown in Fig. 1 before insertion of the working tool. For inserting the working tool 3, the sleeve 5 is moved from its extreme position shown in Fig.
1 to the second extreme position shown in Fig. 4, by compressing the spring 6. The ends of the retainer members 8 move in the guide holes 20 of the sleeve 5 and get from the portions a thereof into the portions b thereof.
At the same time, the retainer members 8 move in the recesses 7 of the bushing 1 in the direction away from the axis of the bushing 1 thus clearing the cross-section of the hole 9 of the bushing 1. Subsequently the shank 2 of the tool 3 is inserted into the hole 9 of the bushing 1 until it bears thereagainst, and the groove 10 is positioned opposite to the recesses 7. Then the sleeve 5 is released by removing the force holding it in the second extreme position, and the sleeve 5 is returned by the spring 6 to its initial position shown in Fig. 1.
The ends of the retainer members 8 in the guide holes 20 of the sleeve 5 move from the portions b back into the portions a. At the same time, the retainer members 8 move in the recesses 7 of the bushing 1 in the direction toward the axis of the bushing 1 so as to obstruct a part of cross-section of the hole 9 until they engage the shank 2 thus retaining it from getting out of the bushing 1.
The working tool 3 is removed from the tool retainer in the same manner.
During operation of the tool, the hammer 14 (Fig. 1) delivers blows to the working tool 3. The energy transmitted to the working tool 3 by the hammer 14 will break concrete 15.
When the tool runs idle, the casing 4 of the percussive tool is retracted away from concrete 15, and the working tool 3 may remain under the hammering action exerted by the hammer 14 so that the working tool will acquire a certain speed and more in the direction of its removal from the bushing 1.
The shank 2 of the working tool 3 will then strike the retainer members 8, and the radial component of the impact load will be transmitted through the ends of the retainer members 8 to the sleeve 5, but this load cannot be transmitted to the bushing 1. This makes it possible to relieve the cross-section of the bushing 1 in the zone of the guide recesses 7 from loads and improve reliability of the tool retainer. As the cross-section of the sleeve 5 (Fig. 3) taking-up the radial loads is substantially greater than the cross-section of the bushing 1, the specific impact load acting on the sleeve 5 is lower thus also improving reliability of the tool retainer. Therefore the tool retainer for a percussive tool is more reliable while being of the same size as prior art tool retainers.

Claims (2)

1. A tool retainer for a percussive tool, comprising a bushing for receiving a shank of a working tool, having at least one guide recess extending at right angle to its axis in which is installed a cylindrical retainer member having its ends protruding outside the bushing, and a sleeve installed for axial reciprocations on the bushing and having at least a pair of guide holes each receiving a respective end of the cylindrical retainer member, the guide holes having portions, which extend in parallel with the axis of the sleeve and support the ends of the cylindrical retainer member when the sleeve is in one extreme position, and inclined portions conjugated therewith, extending in the direction away from the axis of the sleeve and supporting the ends of the cylindrical retainer member when the sleeve is in the second extreme position, the inclined portions extending at an acute angle with respect to the sleeve axis in the direction of removal of the working tool.
2. A tool retainer for a percussive tool as claimed in claim 1, substantially as hereinabove described with reference to, and as shown in the accompanying drawings.
GB08414260A 1983-06-20 1984-06-05 Tool retainer for a percussive tool Expired GB2141659B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SU833607101A SU1253767A1 (en) 1983-06-20 1983-06-20 Arrangement for securing working tool in impact-action machine

Publications (3)

Publication Number Publication Date
GB8414260D0 GB8414260D0 (en) 1984-07-11
GB2141659A true GB2141659A (en) 1985-01-03
GB2141659B GB2141659B (en) 1986-07-02

Family

ID=21069061

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08414260A Expired GB2141659B (en) 1983-06-20 1984-06-05 Tool retainer for a percussive tool

Country Status (9)

Country Link
AT (1) AT389271B (en)
CH (1) CH663176A5 (en)
CS (1) CS258041B1 (en)
DD (1) DD254494A3 (en)
DE (1) DE3421287C2 (en)
GB (1) GB2141659B (en)
SE (1) SE457775B (en)
SU (1) SU1253767A1 (en)
YU (1) YU107184A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2216826A (en) * 1988-04-05 1989-10-18 Gullick Dobson Ltd Drill bit holder
GB2275216A (en) * 1993-02-18 1994-08-24 Nitto Kohki Co Apparatus for fixing an annular cutter to an arbour
EP0768151A1 (en) * 1995-10-09 1997-04-16 HILTI Aktiengesellschaft Tool holder
WO2001085398A1 (en) * 2000-05-12 2001-11-15 Etablissements Montabert Percussive apparatus such as a rock breaker
WO2003024671A2 (en) * 2001-09-17 2003-03-27 Milwaukee Electric Tool Corporation Rotary hammer
US9676038B2 (en) 2011-03-02 2017-06-13 Hilti Aktiengesellschaft Chuck

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007005033A1 (en) * 2007-02-01 2008-08-07 Robert Bosch Gmbh Tool holder for a machine tool, in particular for a hand tool

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT964292B (en) * 1971-09-13 1974-01-21 Kango Electric Hammers Ltd IMPROVEMENTS RELATING TO MACHINES OR PORTABLE IMPACT TOOLS
DE2354168C2 (en) * 1973-10-30 1984-10-04 Robert Bosch Gmbh, 7000 Stuttgart Tool holder for a hammer drill

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2216826A (en) * 1988-04-05 1989-10-18 Gullick Dobson Ltd Drill bit holder
GB2216826B (en) * 1988-04-05 1992-03-04 Gullick Dobson Ltd Retaining devices
GB2275216A (en) * 1993-02-18 1994-08-24 Nitto Kohki Co Apparatus for fixing an annular cutter to an arbour
US5447397A (en) * 1993-02-18 1995-09-05 Nitto Kohki Co., Ltd. Apparatus for fixing an annular cutter to an arbor
GB2275216B (en) * 1993-02-18 1996-02-28 Nitto Kohki Co Apparatus for fixing an annular cutter to an arbor
EP0768151A1 (en) * 1995-10-09 1997-04-16 HILTI Aktiengesellschaft Tool holder
US5807040A (en) * 1995-10-09 1998-09-15 Hilti Aktiengesellschaft Tool bit chuck
FR2808720A1 (en) * 2000-05-12 2001-11-16 Montabert Ets Percussion rock breaker, for excavator or loading shovel, comprises body containing piston and part of tool held in body by transverse key which passes through aligned hole in body into wear sleeve
WO2001085398A1 (en) * 2000-05-12 2001-11-15 Etablissements Montabert Percussive apparatus such as a rock breaker
US6857482B2 (en) 2000-05-12 2005-02-22 Etablissements Montabert Percussive implement of the rock breaker type
KR100755987B1 (en) 2000-05-12 2007-09-06 몽따베르 Rock Breaker Type Impact Device
WO2003024671A2 (en) * 2001-09-17 2003-03-27 Milwaukee Electric Tool Corporation Rotary hammer
WO2003024671A3 (en) * 2001-09-17 2003-05-22 Milwaukee Electric Tool Corp Rotary hammer
GB2384742A (en) * 2001-09-17 2003-08-06 Milwaukee Electric Tool Corp Rotary hammer
GB2384742B (en) * 2001-09-17 2005-12-07 Milwaukee Electric Tool Corp Rotary hammer
US7032683B2 (en) 2001-09-17 2006-04-25 Milwaukee Electric Tool Corporation Rotary hammer
US9676038B2 (en) 2011-03-02 2017-06-13 Hilti Aktiengesellschaft Chuck

Also Published As

Publication number Publication date
YU107184A (en) 1989-10-31
DE3421287C2 (en) 1986-04-24
GB8414260D0 (en) 1984-07-11
AT389271B (en) 1989-11-10
SU1253767A1 (en) 1986-08-30
CH663176A5 (en) 1987-11-30
DE3421287A1 (en) 1984-12-20
ATA199884A (en) 1989-04-15
DD254494A3 (en) 1988-03-02
SE8403240D0 (en) 1984-06-15
SE8403240L (en) 1984-12-21
CS258041B1 (en) 1988-07-15
SE457775B (en) 1989-01-30
GB2141659B (en) 1986-07-02

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920605