Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3918535 A
Publication typeGrant
Publication dateNov 11, 1975
Filing dateMay 23, 1974
Priority dateMay 23, 1973
Also published asCA1012959A1, DE2423902A1, DE2423902B2, DE2423902C3
Publication numberUS 3918535 A, US 3918535A, US-A-3918535, US3918535 A, US3918535A
InventorsEklof Ake Torsten, Romell Gunnar Vigg Riss
Original AssigneeAtlas Copco Ab
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Device for damping the recoil of a tool connected to a hammer machine
US 3918535 A
Abstract
A recoil damping device for a hammer machine in which a heavily prestressed spring is used, the spring being mounting between two supporting surfaces in the machine housing. The tool acts on the spring between the supporting surfaces. These characteristics give as a result that the length of the spring is not influenced by the feeding force.
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent [191 Eldiif et al.

[ 1 Nov. 11, 1975 DEVICE FOR DAMPING THE RECOIL OF A TOOL CONNECTED TO A HAMMER MACHINE lnventors: Ake Torsten Ekliif, Skarholmen;

Gunnar Vigg Riss Romell, Djursholm, both of Sweden [56] References Cited UNITED STATES PATENTS 2.292.867 8/1942 Charles 173/139 X 2,609,813 8/1952 Maurer et a1. 173/139 X 2,638,749 5/1953 Sparano 173/139 X 3,086,501 4/1963 Nielsen 173/139 X 3,114,421 12/1963 McCloud 173/139 X 3,666,024 5/1972 Beaumont 173/105 Prinzm E.\"aminer-l-lenry C. Sutherland Assistant Eraminer-Richard E. Favreau Attorney, Agent, or Firm-Flynn & Frishauf [57] ABSTRACT A recoil damping device for a hammer machine in which a heavily prestressed spring is used, the spring being mounting between two supporting surfaces in the machine housing. The tool acts on the spring between the supporting surfaces. These characteristics give as a result that the length of the spring is not influenced by the feeding force.

8 Claims, 1 Drawing Figure US. Patent Nov. 11, 1975 DEVICE FOR DAMPING THE RECOIL OF A TOOL CONNECTED A HAMMER MACHINE BACKGROUND The present invention relates to hammer machines and concerns a device for damping the recoil of a tool connected to the machine.

A known device of this kind comprises a spring through which feeding force is transferred from the ma chine housing to the tool. That device has the disadvantage that the length of the spring is dependent on the applied feeding force. This means that the position in which the shank of the tool is situated when the hammer piston hits the shank is dependent on the applied feeding force. A machine which comprises a recoil damper of that kind works optimally only together with a certain predetermined feeding force.

SUMMARY OF THE INVENTION The present invention aims at doing away with the above mentioned disadvantage. This is achieved in that a spring is prestressed in the machine housing between two supporting surfaces arranged at a fixed axial distance. Since the spring is prestressed in the machine housing, an applied feeding force results therein that only a part of the force of the spring acting on the machine housing is transferred to the tool. This means that the stress in the spring and consequently the length of the spring is unchanged.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of the invention is described below with reference to the accompanying drawing which shows a hammer drilling machine partly in section.

Detailed Description of Illustrated Embodiment The hammer drilling machine shown in the FIGURE comprises a machine housing 1 in which a forwards and backwards movable hammer piston 3 is arranged. A drill-sleeve 6 is by means of rolling bearings 8, 9 journalled in the machine housing 1. A motor 2 rotates via a toothed wheel 5, the drill-sleeve 6, and a further sleeve 7 a tool 4 which is axially movable in the machine. The rolling bearing 8 rests against a supporting surface 13 arranged in the machine housing 1. A rolling bearing 10 rests against a supporting surface 14, which is arranged at a fixed axial distance from the surface 13, in the machine housing 1. A transferring device rests with a surface 16 against the tool 4 and is pressed forwards by a prestressed spring 12 which via a sleeve 11 rests against the bearing 10.

The machine shown works in the following way. When there is no feeding force applied, the force from the prestressed spring 12 is transferred via the transferring device 15, the drill-sleeve 6, and the bearing 8 to the supporting surface 13 of the machine housing 1. When feeding force is applied to the machine housing 1 the tool 4 is pressed against the surface 16 on the transferring device 15. This does not mean that the stress in the spring is changed but only that the supporting surface 13 is unloaded. During drilling the tool 4 is turned by means of the motor 2 at the same time as it is exposed to impacts from the hammer piston 3. When the tool 4 recoils from the material in which drilling occurs it hits the surface 16 on the transferring device 15 which through this is lifted out of contact with the drillsleeve 6 if the recoil force exceeds a certain value.

Through this the influence of the recoil on the machine housing 1 is damped. The tool 4 is then returned to-.the

position which is independent of the feeding force by the spring 12. i

The above described and illustrated embodiment of the invention is only to be regarded as an example which can be modified within the scope of the subsequent claims.

What we claim is:

l. A recoil damping device for a hammer-type rockdrilling machine which includes a tool, a machine housing coupled to said tool and substantially constantly applying a feeding force to said tool in a working direction, means for additionally supplying impacts to said tool and means for rotating said tool, said tool recoiling after application of said impacts, said recoil damping device damping the recoil of said tool and comprising:

a spring coupled to said machine housing for transferring said feeding force from said machine housing to said tool;

two supporting surfaces in said machine housing and arranged with a fixed relative spacing therebetween in the direction of said feeding force;

two rolling bearings each resting against a respective one of said supporting surfaces;

said tool being coupled to said machine housing so as to act on said spring between said rolling bearings; and

said spring being dimensioned and heavily prestressed between said rolling bearings so that the length of said spring is substantially not influenced by said feeding force applied to said tool.

2. A device according to claim 1 wherein said rolling bearings comprise ball bearings.

3. A device according to claim 1 in which said means for rotating the tool is arranged between said spring and one of said rolling bearings, and wherein a further rolling bearing is provided, said tool rotating means being carried in the machine housing by said one rolling bearing and said further rolling bearing.

4. A device according to claim 2 comprising means for transferring feeding force, which transferring means partly rests against the spring and partly against the tool.

5. A hammer-type rock-drilling machine comprising:

a tool;

a machine housing coupled to said tool and including means for substantially constantly applying a feeding force to said tool in a working direction, means for additionally supplying impacts to said tool and means for rotating said tool, said tool recoiling after application of said impacts; and

a recoil clamping device damping the recoil of said tool and comprising:

a spring coupled to said machine housing for transferring said feeding force from said machine housing to said tool;

two supporting surfaces in said machine housing and arranged with a fixed relative spacing therebetween in the direction of said feeding force;

two rolling bearings each resting against a respective one of said supporting surfaces;

said tool being coupled to said machine housing so as to act on said spring between said rolling bearings; and

said spring being dimensioned and heavily prestressed between said rolling bearings so that the length of said spring is substantially not influenced 4 being carried in the machine housing by said one rolling bearing and said further rolling bearing.

8. A device according to claim 7 comprising means for transferring feeding force, which transferring means partly rests against the spring and partly against the tool.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,918,535 DATED November 1 1 1 975 lNVENTOR(S) Ake Torsten EKLOF et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, change priority data to read:

May 23 1973 Sweden .7307224-1--;

In the Abstract, line 3 change "mounting" to -mounted.

Signed and Scaled this seventeenth D ay Of February 1 9 76 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ojParents and Trademarks

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2292867 *Jan 15, 1940Aug 11, 1942Gas Tool Patents CorpDrilling apparatus
US2609813 *Jul 8, 1949Sep 9, 1952Chicago Pneumatic Tool CoGas hammer
US2638749 *Jan 19, 1951May 19, 1953Henry J ClayElectropneumatic hammering device
US3086501 *Jun 24, 1959Apr 23, 1963Henry E KyburgFluid-operated hammer
US3114421 *Apr 4, 1960Dec 17, 1963Skil CorpPneumatic system for a rotary hammer device
US3666024 *Jul 29, 1970May 30, 1972Beaumont Richard WRock drill
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4141671 *Apr 20, 1977Feb 27, 1979Tarsoly Balazs KTool gas turbine motor
US4161990 *Oct 31, 1977Jul 24, 1979Atlas Copco AktiebolagRock drilling apparatus
US8430182Dec 29, 2005Apr 30, 2013Black & Decker Inc.Power tool housing
DE10021355B4 *May 2, 2000Apr 28, 2005Hilti AgSchlagendes Elektrohandwerkzeuggerät mit schwingungsentkoppelten Baugruppen
Classifications
U.S. Classification173/162.1, 173/105
International ClassificationB25D17/24, B25D17/00, E21B17/02, E21B1/00, E21B1/38, E21B17/03
Cooperative ClassificationB25D17/24
European ClassificationB25D17/24