GB1588645A - Tool holder - Google Patents

Tool holder Download PDF

Info

Publication number
GB1588645A
GB1588645A GB4400477A GB4400477A GB1588645A GB 1588645 A GB1588645 A GB 1588645A GB 4400477 A GB4400477 A GB 4400477A GB 4400477 A GB4400477 A GB 4400477A GB 1588645 A GB1588645 A GB 1588645A
Authority
GB
United Kingdom
Prior art keywords
tool holder
tool
cap
holder according
sleeve
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
GB4400477A
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 GB1588645A publication Critical patent/GB1588645A/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
    • 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
    • B25D2217/0042—Ball-shaped locking members
    • 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
    • B25D2217/0057—Details related to cleaning or cooling the tool or workpiece
    • B25D2217/0065—Use of dust covers

Abstract

In a powered hand tool, to couple a percussive and/or rotating tool (8) to a spindle (1) of the powered hand tool, a tool holder is used in which a holding element (11) projecting radially into the tool-locating bore (6) engages in an allocated recess (10) of the tool shank (7). At its front side facing the point of the tool (8), a bowl-like protective cap (15) is put over the tool holder. The protective cap (15) seals off the tool-locating bore (6) from the ingress of drillings. <IMAGE>

Description

(54) A TOOL HOLDER (71) We, ROBERT BOscFi GmbH, a German company of Postfach 50, 7000 Stuttgart 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a tool holder for percussion and/or rotary drilling machines, provided with a protective cap.
Such tool holders usually comprise one or more elements projecting radially into a toolreceiving bore in the tool holder and arranged to engage the shank of a tool inserted in the tool holder to retain the tool therein.
It has been shown that debris entering into the receiving bore of a tool holder, which occurs more especially during drilling upwards into a ceiling, leads to very considerable wear on the working parts of the tool holder and on the tool shank. This is because the drilling dust has the effect of a grinding agent.
In accordance with the invention, a tool holder is provided in which an element projecting radially into a tool-receiving bore in the tool holder is arranged to engage the shank of a tool inserted in the tool holder to retain the tool therein, a cup-like protective cap of elastomeric material being mounted on the tool holder with the base of the cup adjacent the forward end of the tool holder, means being provided for retaining the cap on the forward portion of the tool holder, the base of the cup being provided with an opening for the passage of the tool into and out of the tool holder, and the diameter of the opening and the diameter of the bore in the tool receiver being so related that, in use, the cap sealingly engages the shank of a tool in the tool-receiving bore so as to prevent the ingress of debris into the tool holder.
With such a tool holder, the ingress of debris into the interior of the tool holder is effectively prevented by the seal which is formed around the shank of the tool by the opening in the base of the cup of the protective cap.
The cap may be retained on the tool holder by a radially inwardly directed rib engaging in a groove in the tool holder. The rib and the groove are preferably annular and may be semicircular in cross-section.
In some tool holders, the tool retaining element is movable radially and can be held in the tool retaining position by an axially movable sleeve surrounding the tool bolder. In that case, the radially inwardly directed rib may also form an abutment limiting movement of the sleeve in a direction towards the forward end of the tool holder. With such an arrangement, it is also desirable for the protective cap to be provided with a sleeve-like extension which extends over the axially movable sleeve. This prevents dust and debris from entering the interior of the tool holder when the sleeve is moved away from the abutment to allow the retaining element to release the tool.
In a preferred form of the invention, the cap is frictionally mounted on the tool holder to permit rotation of the tool holder relatively to the cap when the latter engages a stationary surface. With that arrangement, the cap is held stationary against the stationary surface, which may be a ceiling or wall, whilst the tool holder continues to rotate the tool. In that way, the life of the cap is considerably increased. Furthermore, to increase the coefficient of friction between the cap and the stationary surface, an area, which may be annular, on the outer surface of the cup is provided with teeth or the like. To increase the frictional effect still further, at least a part of the said area is arranged at a greater distance from the rotary axis of the tool holder than is the rib where it frictionally engages the groove.
In a modified form of seal between the cap and the shank of the tool, the opening is formed by the aperture in a ring of foam material inserted in the cap on the inside of the base of the cup. The foam ring is easily replaced when it becomes too worn to provide an effective seal.
The opening in the base of the cup can be of the same diameter as the bore in the tool holder but it is preferably slightly less, good results having been achieved when it is 1 mm less.
Thus, with a tool shank having a diameter of 9 mm, that of the opening would be 8 mm.
Finally, the elastomeric material from which the cup-like protective cap is made, is preferably wear and temperature resistant.
In order that the invention may be clearly understood and readily carried into effect, various embodiments of tool holders in accordance therewith and of the protective caps themselves, will now be described by way of example with reference to the accompanying drawings in which, Figure 1 is a longitudinal section through one form of protective cap mounted on a tool holder; Figure 2 is a similar section through another form of protective cap mounted on the same tool holder; and Figure 3 is a section through yet another form of protective cap mounted on a similar tool holder.
The tool holder illustrated in Figure 1 of the drawing is pushed over the tool spindle 1 of a percussion drilling machine, such as a drill hammer, not shown in detail in the drawing. The spindle 1 projects forwardly from the housing of the drill hammer and performs rotary and axial percussion movements.
The tool holder comprises a coupling sleeve 2 which is pushed over the free end of the tool spindle 1 by means of a spindle-receiving bore 3. Torque is transmitted from the spindle 1 to the sleeve 2 through ribs 4 on the inner wall of the bore 3 and grooves 5 in the spindle. The coupling sleeve 2 has a tool receiving bore 6 open at the forward end to receive the shank 7 of a tool - in this instance a drill 8 - il bore 6 being arranged co-axial with respect to the bore 3. Moreover, torque is transmitted from the sleeve 2 to the tool 8 through opposite ribs arranged on the inner wall of the bore 6 and grooves 9 in the tool shank 7 which open at the rear end of the tool shank 7.
The rear end of the tool shank 7 engages the forward end of the spindle 1 so that axial impacts can be transmitted to the tool shank 7 by the spindle 1. Two recesses 10 are closed axially at both ends. Two elements in the form of balls 11 are arranged on the outer surface of the tool shank 7 displaced by 900 with respect to the grooves 9. The balls 11 project radially into the bore 6 and engage the recesses 10 to retain the tool 8 in the tool holder. The balls 11 are movably guided in radial bores 12 in the coupling sleeve 2 so that the tool 8 can be removed from the tool holder.
An axially movable sleeve 14 which overlaps the external openings from the radial bores 12 surrounds the tool holder and is guided axially on the sleeve 2. The sleeve 14 is displaceable against the force of a spring 13. Thus, in the operative condition illustrated in Figure 1, the balls 11 are prevented from radial movement and the shank 7 inserted in the bore 6 is prevented from falling out. The spring 13 retains the sleeve 14 in the illustrated operative position of the tool holder against the rear end of an elastomeric cup-like protective cap 15, having a base 18, pushed over the forward por- tion of the tool holder so as to be mounted on the tool holder with the base 18 of the cup adjacent the forward end of the tool holder.
Means, in the form of a radially inwardly directed annular rib 16 on the cap and an annular groove 17 provided in the sleeve 2 of the tool holder, are provided for retaining the cap 15 on the forward portion of the tool holder.
The base 18 of the cap 15 is provided with an opening 19 for the passage of the tool 8 into and out of the tool holder. The diameter of the opening 19 and the diameter of the bore 6 are so related that, when the tool 8 is inserted in the bore 6 and the drilling machine is in use the lip of the opening 19 sealingly engages the shank 7 of the tool 8 and prevents the ingress of debris into the tool holder, even when drilling upwards into the ceiling. To this end, the lip engages the shank with a certain amount of pretension. This pre-tension can be achieved by arranging for the diameter of the opening 19 to be one millimetre less than the diameter of the bore 6 corresponding to that of the shank 7.
For example, when the latter diameter is 10 mm the former can be 9 mm.
The annular rib 16 is arranged at the rear end of the protective cap 15 remote from the tool 8 so as to form an abutment against which the sleeve 14 is urged by the spring 13, the abutment limiting movement of the sleeve 14 in a direction towards the forward end of the tool holder. In Figure 1, the annular rib 16 is substantially semi-cricular in cross-section where it engages the groove 17.
The diameters of the annular rib 16 and the annular groove 17 are so calculated that the cap 15 is a relatively loose fit on the tool holder.
The reason for this is to permit rotation of the tool holder relatively to the cap when the latter engages a stationary surface, such as a ceiling or a wall, in which a hole is being drilled. This prevents undue wear occurring on the cap 15 so that its life is considerably increased. In Figures 1 and 2, an annular rim 20 provides an annular area on the outer surface of the base of the cup at least a part of which is at a greater distance from the rotary axis of the tool holder than is the rib 16 where it frictionally engages the groove 17.
As shown in the drawings, the rim 20 is smooth. It can, however, be provided with teeth or the like so as to roughen its outer surface and provide an increased coefficient of friction between it and the said stationary surface.
The second embodiment of a tool holder illustrated in Figure 2, differs from the embodiment of Figure 1 by a somewhat modified cuplike protective cap 25. The protective cap 25 is provided with a sleeve-like extension 26 which extends away from the forward end of the tool holder and beyond the forward end of the axially movable sleeve 14. In this manner, when drilling overhead for example, drilling dust can also be prevented from entering the annular gap formed between the inner surface of the sleeve 14 and the outer surface of the sleeve 2, thus preventing its disruptive effect.
In the third embodiment illustrated in Figure 3, for the sake of simplicity, only the coupling sleeve 2 of the tool holder with a modified pushed-on protective cap 35 is illustrated. With this protective cap 35, the sealing lip of the opening 39 is formed by the aperture in a ring 40 of foam material inserted on the inside of the base portion 38 of the protective cap 35. Since the diameter of the aperture in the ring of foam material 40 is related to that of the bore receiving the shank of the tool in exactly the same way as the opening 19 is related to the bore 6, it sealingly engages the outside of the tool shaft 7, not illustrated in Figure 3, with a certain pretension and seals the inside of the coupling sleeve 2 against the ingress of debris. In this embodiment, although the aperture in ring 40 sealingly engages the shank 7, the diameter of the bore 41 in the base portion 38 is large enough to prevent free passage for the shank 7 of the drill 8, being greater than the outer diameter of the shank 7 by a small clearance. The ring of foam material 40 which, for example can be made of polyurethane foam, can be easily exchanged for a new one when it becomes worn.
The protective cap 35 can also be provided with a sleeve-like extension 26 - as illustrated in Figure 2.
The material from which the protective caps are made, is preferably a wear and temperature resistant elastomer.
WHAT WE CLAIM IS: 1. A tool holder for percussion and/or rotary drilling machines, in which an element projecting radially into a tool-receiving bore in the tool holder is arranged to engage the shank of a tool inserted in the tool holder to retain the tool therein, a cup-like protective cap of elastomeric material being mounted on the tool holder with the base of the cup adjacent the forward end of the tool holder, means being provided for retaining the cap on the forward portion of the tool holder, the base of the cup being provided with an opening for the passage of the tool into and out of the tool holder, and the diameter of the opening and the diameter of the bore in the tool receiver being so related that, in use, the cap sealingly engages the shank of a tool in the tool-receiving bore so as to prevent the ingress of debris into the tool holder.
2. A tool holder according to claim 1, in which the means provided for retaining the cap on the tool holder comprise a radially inwardly directed rib engaging in a groove provided in the tool holder.
3. A tool holder according to claim 2, in which the rib and the groove are annular.
4. A tool holder according to claim 3, in which the rib and the groove are semi-circular in cross-section.
5. A tool holder according to any one of claims 2 to 4, in which the tool retaining element is movable radially and can be held in the tool retaining position by an axially movable sleeve surrounding the tool holder, the radially inwardly directed rib on the cap forming an abutment limiting movement of the sleeve in a direction towards the forward end of the tool holder.
6. A tool holder according to any preceding claim, in which the protective cap has a sleevelike extension extending over the tool holder in a direction away from the forward end thereof.
7. A tool holder according to claim 5 and claim 6, in which the sleeve-like extension extends beyond the forward end of the axially movable sleeve.
8. A tool holder according to claim 5 or claim 5 and claim 6, in which the axially movable sleeve is urged into engagement with the abutment by a spring.
9. A tool holder according to any preceding claim, in which a ring of foam material is inserted in the cap on the inside of the base of the cup, the aperture in the ring forming the opening in the base of the cup.
10. A tool holder according to any preceding claim, in which the cup-like protective cap consists of a wear and temperature resistant elastomer.
11. A tool holder according to any preceding claim, in which the cap is frictionally mounted on the tool holder to permit rotation of the tool holder relatively to the cap when the latter engages a stationary surface.
12. A tool holder according to claim 11 and claim'2 or claim 2 and any one of claims 3 to 10, in which the diameters of the rib and the groove are such that the cap is a relatively loose fit on the tool holder.
13. A tool holder according to claim 12, in which an area of the outer surface of the base of the cup is arranges to engage a stationary surface, at least a part of the said area being at a greater distance from the rotary axis of the tool holder than is the rib where it frictionally engages the groove.
14. A tool holder according to claim 13, in which the said area is roughened to increase the coefficient of friction between it and the said stationary surface.
15. A tool holder according to claim 14, in which the said area is annular.
16. A tool holder according to claim 15, in which the annular area is provided with teeth or the like.
17. A tool holder according to any preceding claim, in which the diameter of the opening in the base of the cup, or of the aperture in the foam ring, is less than the diameter of the toolreceiving bore by 1 mm.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (17)

**WARNING** start of CLMS field may overlap end of DESC **. holder and beyond the forward end of the axially movable sleeve 14. In this manner, when drilling overhead for example, drilling dust can also be prevented from entering the annular gap formed between the inner surface of the sleeve 14 and the outer surface of the sleeve 2, thus preventing its disruptive effect. In the third embodiment illustrated in Figure 3, for the sake of simplicity, only the coupling sleeve 2 of the tool holder with a modified pushed-on protective cap 35 is illustrated. With this protective cap 35, the sealing lip of the opening 39 is formed by the aperture in a ring 40 of foam material inserted on the inside of the base portion 38 of the protective cap 35. Since the diameter of the aperture in the ring of foam material 40 is related to that of the bore receiving the shank of the tool in exactly the same way as the opening 19 is related to the bore 6, it sealingly engages the outside of the tool shaft 7, not illustrated in Figure 3, with a certain pretension and seals the inside of the coupling sleeve 2 against the ingress of debris. In this embodiment, although the aperture in ring 40 sealingly engages the shank 7, the diameter of the bore 41 in the base portion 38 is large enough to prevent free passage for the shank 7 of the drill 8, being greater than the outer diameter of the shank 7 by a small clearance. The ring of foam material 40 which, for example can be made of polyurethane foam, can be easily exchanged for a new one when it becomes worn. The protective cap 35 can also be provided with a sleeve-like extension 26 - as illustrated in Figure 2. The material from which the protective caps are made, is preferably a wear and temperature resistant elastomer. WHAT WE CLAIM IS:
1. A tool holder for percussion and/or rotary drilling machines, in which an element projecting radially into a tool-receiving bore in the tool holder is arranged to engage the shank of a tool inserted in the tool holder to retain the tool therein, a cup-like protective cap of elastomeric material being mounted on the tool holder with the base of the cup adjacent the forward end of the tool holder, means being provided for retaining the cap on the forward portion of the tool holder, the base of the cup being provided with an opening for the passage of the tool into and out of the tool holder, and the diameter of the opening and the diameter of the bore in the tool receiver being so related that, in use, the cap sealingly engages the shank of a tool in the tool-receiving bore so as to prevent the ingress of debris into the tool holder.
2. A tool holder according to claim 1, in which the means provided for retaining the cap on the tool holder comprise a radially inwardly directed rib engaging in a groove provided in the tool holder.
3. A tool holder according to claim 2, in which the rib and the groove are annular.
4. A tool holder according to claim 3, in which the rib and the groove are semi-circular in cross-section.
5. A tool holder according to any one of claims 2 to 4, in which the tool retaining element is movable radially and can be held in the tool retaining position by an axially movable sleeve surrounding the tool holder, the radially inwardly directed rib on the cap forming an abutment limiting movement of the sleeve in a direction towards the forward end of the tool holder.
6. A tool holder according to any preceding claim, in which the protective cap has a sleevelike extension extending over the tool holder in a direction away from the forward end thereof.
7. A tool holder according to claim 5 and claim 6, in which the sleeve-like extension extends beyond the forward end of the axially movable sleeve.
8. A tool holder according to claim 5 or claim 5 and claim 6, in which the axially movable sleeve is urged into engagement with the abutment by a spring.
9. A tool holder according to any preceding claim, in which a ring of foam material is inserted in the cap on the inside of the base of the cup, the aperture in the ring forming the opening in the base of the cup.
10. A tool holder according to any preceding claim, in which the cup-like protective cap consists of a wear and temperature resistant elastomer.
11. A tool holder according to any preceding claim, in which the cap is frictionally mounted on the tool holder to permit rotation of the tool holder relatively to the cap when the latter engages a stationary surface.
12. A tool holder according to claim 11 and claim'2 or claim 2 and any one of claims 3 to 10, in which the diameters of the rib and the groove are such that the cap is a relatively loose fit on the tool holder.
13. A tool holder according to claim 12, in which an area of the outer surface of the base of the cup is arranges to engage a stationary surface, at least a part of the said area being at a greater distance from the rotary axis of the tool holder than is the rib where it frictionally engages the groove.
14. A tool holder according to claim 13, in which the said area is roughened to increase the coefficient of friction between it and the said stationary surface.
15. A tool holder according to claim 14, in which the said area is annular.
16. A tool holder according to claim 15, in which the annular area is provided with teeth or the like.
17. A tool holder according to any preceding claim, in which the diameter of the opening in the base of the cup, or of the aperture in the foam ring, is less than the diameter of the toolreceiving bore by 1 mm.
rotary tools, substantially as herein described
with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.
GB4400477A 1976-11-23 1977-10-21 Tool holder Expired GB1588645A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19762653082 DE2653082A1 (en) 1976-11-23 1976-11-23 TOOL HOLDER

Publications (1)

Publication Number Publication Date
GB1588645A true GB1588645A (en) 1981-04-29

Family

ID=5993733

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4400477A Expired GB1588645A (en) 1976-11-23 1977-10-21 Tool holder

Country Status (3)

Country Link
CH (1) CH627231A5 (en)
DE (1) DE2653082A1 (en)
GB (1) GB1588645A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002062534A2 (en) * 2001-02-07 2002-08-15 Robert Bosch Gmbh Tool holder for a hand tool
GB2405114A (en) * 2003-07-30 2005-02-23 Bosch Gmbh Robert Tool receptacle, in particular a quick-change clamping chuck
GB2426944B (en) * 2005-06-09 2010-09-22 Jacobs Chuck Mfg Co Drill chuck

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2844110A1 (en) * 1978-10-10 1980-04-24 Bosch Gmbh Robert HAND TOOL MACHINE, ESPECIALLY CHISEL HAMMER
US4247122A (en) * 1979-01-31 1981-01-27 Black & Decker Inc. Dust sealing mechanism
DE2939614A1 (en) * 1979-09-29 1981-04-16 Robert Bosch Gmbh, 7000 Stuttgart TOOL HOLDER
DE3406482A1 (en) * 1984-02-23 1985-08-29 Robert Bosch Gmbh, 7000 Stuttgart Dust protection cap for the tool holder of hand-held drills or hammer drills
DE3515661A1 (en) * 1985-05-02 1986-11-06 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt ELECTROPNEUMATIC TORQUE DRILL
DE19516034A1 (en) * 1995-05-04 1996-11-07 Hilti Ag Torque transmission device for hand tools

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002062534A2 (en) * 2001-02-07 2002-08-15 Robert Bosch Gmbh Tool holder for a hand tool
WO2002062534A3 (en) * 2001-02-07 2003-03-20 Bosch Gmbh Robert Tool holder for a hand tool
GB2405114A (en) * 2003-07-30 2005-02-23 Bosch Gmbh Robert Tool receptacle, in particular a quick-change clamping chuck
GB2426944B (en) * 2005-06-09 2010-09-22 Jacobs Chuck Mfg Co Drill chuck
US7997587B2 (en) 2005-06-09 2011-08-16 Jacobs Chuck Manufacturing Company Drill chuck
US8191902B2 (en) 2005-06-09 2012-06-05 Jacobs Chuck Manufacturing Company Drill chuck
US8511692B2 (en) 2005-06-09 2013-08-20 Jacobs Chuck Manufacturing Company Drill chuck
US8695991B2 (en) 2005-06-09 2014-04-15 Apex Brands, Inc. Drill chuck
US9221105B2 (en) 2005-06-09 2015-12-29 Apex Brands, Inc. Drill chuck

Also Published As

Publication number Publication date
DE2653082A1 (en) 1978-05-24
CH627231A5 (en) 1981-12-31

Similar Documents

Publication Publication Date Title
US4502824A (en) Tool chuck
US4691929A (en) Drill bit chuck for drilling and cutting devices
US5888031A (en) Drilling device
US7644929B2 (en) Hand-held power tool with a replaceable tool fitting
US6073705A (en) Power-driven striking tool having a mechanism for setting the circumferential angle of tool bits attached to the striking tool
US6536780B2 (en) Hand power tool
US5603516A (en) Drilling and/or chipping tool
US4834596A (en) Quick change spindle adaptor for tool holder
US20090145620A1 (en) Hand-held power tool with a chuck and an associated working tool
JPS6055275B2 (en) tool holder
US6179300B1 (en) Tool holder
GB1588645A (en) Tool holder
GB2360240A (en) Hand machine tool with tool release means
ATE246580T1 (en) TOOL HOLDER FOR MILLING DRUMS OF A MILLING DEVICE
US5324145A (en) Tool bit and chuck for use in percussion drilling and chiseling
GB2383288A (en) A Hand Machine Tool
EP0668127B1 (en) Tool holder for a rotary and/or chisel hammer
US6527280B2 (en) Hand held power tool
US20030089509A1 (en) Hand machine tool
US20070235950A1 (en) Chuck
JP4369556B2 (en) Dust-proof cover for drilling tools
GB2326123A (en) Hammer drill with dust seal for tool holding assembly
US5944126A (en) Resilient, non-rotating seal for rock drill
GB1569843A (en) Surgical handpiece for holding and driving a surgical tool
GB2136480A (en) Pick holding arrangement

Legal Events

Date Code Title Description
PS Patent sealed
PE20 Patent expired after termination of 20 years

Effective date: 19970324