SE1451622A1 - Pneumatic drilling tool with disposal collector - Google Patents

Abstract

A pneumatic drilling tool (10) comprising a spindle (21), a pneumatic motor for driving said spindle (21), an air inlet portion (14) for supplying pressurised air to drive the motor, a housing (12,13,25) that at least partly houses the motor and the spindle (21), wherein the spindle (21) is configured to hold a drilling implement (11), which is arranged to extend out from a front housing (12) of said housing during operation. A disposal collector (18) is arranged for collecting drill chips (22) during operation, wherein an air nozzle (23) is arranged in a flow passage (30) adjacent the front housing (12) , the nozzle having an outlet (26) that is directed away from the front housing (12) into the disposal collector (18) to thereby create a suction effect from the front housing (12) into the disposal collector (18), which disposal collector (18) has a permeable portion (28) that allows air to pass through it but keeps the drill chips inside, wherein an air conduction conduit (15) is arranged from the air inlet portion (14) to the air nozzle (23) to provide the suction effect.(Elected for publication: Fig. 1)

Description

Pneumatic drilling tool with disposal collector The invention relates to a pneumatic drilling tool with a disposal collector. Specifically, the invention relates to a pneumatic power tool with a self-supported disposal collector arranged upon it.

Background During operation of machining or material removal power tools such asdrilling machines or grinders debris is produced. Most such tools aretherefore provided with an arrangement for collecting such debris.Normally, a hose from a separate vacuum unit is arranged and connected to the debris producing end of the power tool.

The arrangement of a separate vacuum unit for removing debris ishowever cumbersome and it would be beneficial to have the disposal unit arranged as an integrated part of the tool.

In a known pneumatic grinder the exhaust air from the grinder isconveyed so as to encapsulate and direct debris into a disposal unitarranged close to the grinding disc of the grinder. This isadvantageous as it implies that a separate vacuum unit in so longerneeded. A problem with the arrangement is however that it needs to beoptimised for a specific operation speed of the motor, such that itwill be less functional for any other motor speed. Further, thearrangement requires that the outlet is located close to the toolimplement such that the outlet air may be conveyed to the grindingdisc and force the debris towards a collector. A further problem isthat all of the exhaust air needs to pass through the collector, whichsets high demands on the construction of the collector, such as the on the permeability of the collector walls.

There is a need for a pneumatic drilling tool with an improvedarrangement for collecting debris that is self-supported, i.e. not dependent on external driving.

Summary of the invention An object of the invention is to provide self-supporting debriscollector for a pneumatic drilling tool that is reliable and independent of motor speed.

This object is achieved by the invention according to claim l, whichrelates to a pneumatic drilling tool comprising: - a spindle, - a pneumatic motor for driving said spindle, - an air inlet portion for supplying pressurised air to drive themotor, - a housing that at least partly houses the motor and the spindle,wherein the spindle is configured to hold a drilling implement, whichis arranged to extend out from a front housing of said housing duringoperation, and- a disposal collector for collecting drill chips, wherein a flowpassage is arranged to connect the disposal collector to the fronthousing. An air nozzle is arranged in the flow passage, the nozzlehaving an outlet that is directed away from the front housing into thedisposal collector to thereby create a suction effect from the fronthousing towards the disposal collector, which disposal collector has apermeable portion that allows air to pass through it but keeps thedrill chips inside, wherein an air conduction conduit is arranged from the air inlet portion to the air nozzle to provide the suction effect.

In a specific embodiment flow restrictions are arranged in the flowpassage that restricts the sectional area of the flow passage aroundthe nozzle, so as to create a venturi effect and increase the suction effect when in operation.

In another embodiment a main valve is arranged in the air inlet portion, which is shiftable between an open and a closed position, and which in the open position allows air to pass from the air inlet portion to the motor, and wherein an outlet conduit is arranged on an output side of the main valve, which connects the air inlet portion with the air nozzle when the main valve is open.

In yet another embodiment a sensor is arranged to monitor the pressurein the disposal collector and to alert if the pressure exceeds apredetermined threshold pressure indicating that the disposal collector needs to emptied or replaced.

Other features and advantages of the invention will be apparent from the figures and from the detailed description of the shown embodiment.

Short description of the drawings In the following detailed description reference is made to the accompanying drawings, of which: Fig. 1 is a perspective view of a pneumatic drilling tool in accordance with a specific exemplifying embodiment of the invention; Fig. 2 is a front view of the pneumatic drilling tool in fig. l; Fig. 3 is a sectional view of the pneumatic drilling tool along the line III-III in fig. 2; Fig. 4 is a side view of the specific embodiment of the pneumatic drilling tool; Fig. 5 is a sectional view of the pneumatic drilling tool along the line V-V in fig. 4; Fig. 6 is a perspective view from below of the specific embodiment of the pneumatic drilling tool; and Fig. 7 is a detailed view of a part of fig. 6.

Detailed description of the shown embodiment of the invention In fig. 1 a pneumatic drilling tool 10 according to a specific exemplifying embodiment of the invention is shown. The drilling tool10 has a housing 25 that houses a pneumatic motor and a spindle, whichis driven by said motor. A rear part of the spindle is covered by arear housing part 13. The spindle is configured to hold a drillingimplement 11, which is arranged to extend out from a front housingpart 12. A disposal collector 18 for collecting drill chips duringoperation is arranged adjacent the front housing part 13. A controlpanel 24 is arranged on a rear end of the drilling tool 10. Thecontrol panel 24 typically comprises a start button, a release buttonand a retract button. The retract button interrupts an on-goingoperation and the release button is utilised when the tool is moved inand out of working position as described below. An air inlet portion14 is arranged at the lower end of the drilling tool. An emergencystop 19 is arranged at the air inlet portion 14 to rapidly close a main valve arranged inside said air inlet portion 14.

An air conduit 15 is arranged to conduct pressurised air from an airconduit inlet 16 at the air inlet portion 14 to an air conduit outlet17 at a flow passage 30 connecting the front housing part 12 and a disposal collector 18. As an alternative the air conduit 15 may bearranged inside tool housing 25. An advantage of having the conduit onthe outside of the tool is that it may be implemented on existing tool without demanding a very big effort.

The general function of the drilling tool 10 will now be describedwith reference to figure 3, which shows a sectional view of the drilling tool along the line III-III in figure 2.

In figure 3 a mantle portion 32 that forms an extension of the fronthousing part is shown. This mantle portion 32 is not shown in the other figures. The mantle portion 32 serves two main purposes; firstly it may be used to position and fix the drilling tool with respect to a fixture where drilling operations are to be performed. The diameter ofthe mantle portion 32 may be reduced by pressing the release button onthe control panel 24. In the release state the mantle portion 32 maybe fitted into a fixture hole and by pressing the release button onceagain when the mantle portion 32 is in location it will expand so asto fix the mantle portion 32 inside the fixture hole in order to hold the drilling lO tool still.

The mantle portion 32 encloses the drilling implement ll. As a consequence, when a suction force is created in the flow passage 30,the chips 22 that are removed during the drilling operation will beconveyed from inside of the mantle portion 32 into the front housingpart l2 and further into the disposal collector l8, via a suction port 29 and the flow passage 30.

The disposal collector l8 has a permeable portion 28 that allows airto pass through it but keeps the drill chips 22 inside. The permeableportion 28 may extend over the whole envelope surface of the disposalcollector l8 or may extend over only a portion of envelope surface depending on the application. Often, a cooling liquid is used. Thecooling may be applied through the centre of the drilling implementand will enclose the drill chips 22 and hence be sucked into the disposal collector l8 along with said chips. For such applications thedisposal collector l8 needs to be adapted to withheld not only metal chips, but also a liquid. Since the liquid and the drill chips will end up in the lower portion of the disposal collector l8, it may be agood idea to provide the air permeable portions 28 in the upperportion of the disposal collector l8, i.e. close to the flow passagein which the air nozzle 23 is arranged. The permeable portions may bearranged as net, as pockets, or as any other gas allowing detail or fabric.

The disposal collector l8 may also be arranged at a distance from thepower tool l0. The flow passage 30 may in one embodiment be a hose that conveys air, cooling liquid and chips towards a distant towards a disposal collector arranged at a distance from the power tool. Thesize of the disposal collector may be adapted to different applications and The function of the suction system will now be described withreference to figure 5. Figure 5 is a sectional view of the disposal collector l8 taken along the line V-V in figure 4.

An air nozzle 23 is arranged inside the flow passage 30 close to thesuction port 29 that opens from the front housing l2. The nozzle 23has an outlet 26 that is directed away from the front housing l2,downwards, into the disposal collector l8 to thereby create a suctioneffect from the front housing l2 into the disposal collector l8. Inthe shown embodiment flow restrictions 3l are arranged in the flowpassage 30 that restricts the sectional area of the flow passage 30around the nozzle 23, so as to create an increased venturi effect and increase the suction effect when in operation.

The air flow created by pressurised air exhausted from the outlet 26of the air nozzle 23 is directed downwards in the figure. Liquid andsolid particles that are sucked through the suction port 22 will betrapped in the bottom of the disposal collector and the pressurisedair will be exhausted through the air permeable portions 28, whichpreferably are located in the upper portion of the disposal collector l8.

In a specific embodiment of the invention a sensor is arranged tomonitor the pressure in the disposal collector l8 and to alert if thepressure exceeds a predetermined threshold pressure indicating thatthe disposal collector l8 needs to emptied or replaced. The sensor maye.g. be a pressure sensor or a flow meter arranged in connection tothe air conduction conduit l5. The threshold may be empirically set soas to allow an on-going operation to be concluded before the disposalcollector l8 needs to emptied or replaced, or it may be set to automatically initiate a termination of an on-going operation.

The function of the air provision system for the suction system willnow be described with reference to figure 7. Figure 7 is a detailed view of a part of the drilling tool shown in figure 6.

The air inlet portion l4 is adapted for connection to a supply unit of pressurised air, such as an air hose. A main valve 20 is arranged inthe conduit that connects the air inlet portion l4 with the pneumaticmotor (not shown). The main valve 20 may be positioned in an open or a closed position. A separate regulator (not shown) is arranged betweenthe main valve 20 and the motor for providing a correct pressure orflow to the motor. Hence the pressure will be the same on both sides of the main valve 20 when positioned in the open state.

An outlet conduit 27 is arranged on the output side of the main valve20. The outlet conduit 27 connects the air inlet portion l4 with theair nozzle 23 when the main valve is open. Given that no pressure islost over the main valve 20 the pressure will be held constant,typically about 6.3 bars at the inlet of the outlet conduit 27. Theoutlet conduit 27 and the air conduction conduit l5 will however implya certain controlled choking effect such that the pressure acting atthe air nozzle 23 is only a fraction of the full pressure. It isobvious for a skilled person to try out a pressure that is suitablefor a specific type of disposal collector l8 and for a specific construction of a suction port 29, front housing l2 etc.

An advantage of having the outlet conduit 27 for supply of pressurisedair to the air suction system located at the output side of the mainvalve 20 is that the suction system will automatically be initiatedi.e. and when the machine is turned on, when the main valve is opened, automatically shut-off when the machine is turned off, i.e. when themain valve is closed. It may however also be possible to have aseparate valve for controlling the air supply to the suction system such that it may be individually controlled.

Above, the invention has been described with reference to a specificembodiment. The invention is however not limited to this embodiment.It is obvious to a person skilled in the art that the inventioncomprises further embodiments within its scope of protection, which is defined by the following claims.

Claims (1)

1. Claims A pneumatic drilling tool (10) comprising: - a spindle (21), - a pneumatic motor for driving said spindle (21), - an air inlet portion (14) for supplying pressurised air todrive the motor, - a housing (12,13,25) that at least partly houses the motorand the spindle (21), wherein the spindle (21) is configured tohold a drilling implement (11), which is arranged to extend outfrom a front housing (12) of said housing during operation, and - a disposal collector (18) for collecting drill chips (22),wherein a flow passage (30) is arranged to connect the disposalcollector (18) to the front housing (12), characterised in thatan air nozzle (23) is arranged in the flow passage (30) thenozzle having an outlet (26) that is directed away from the fronthousing (12) into the disposal collector (18) to thereby create asuction effect from the front housing (12) into the disposalcollector (18), which disposal collector (18) has a permeableportion (28) that allows air to pass through it but keeps thedrill chips inside, wherein an air conduction conduit (15) isarranged from the air inlet portion (14) to the air nozzle (23) to provide the suction effect. The pneumatic drilling tool (10) according to claim 1, whereinflow restrictions (31) are arranged in the flow passage (30) thatrestricts the sectional area of the flow passage around thenozzle, so as to create a venturi effect and increase the suction effect when in operation. The pneumatic drilling tool (10) according to claim 1 or 2, wherein a main valve (20) is arranged in the air inlet portion(14), which is shiftable between an open and a closed position,and which in the open position allows air to pass from the air inlet portion (14) to the motor, and wherein an outlet conduit (27) is arranged on an output side of the main valve (20), whichconnects the air inlet portion (14) with the air nozzle (23) when the main valve is open. The pneumatic drilling tool (10) according to claim 1 or 2,wherein a sensor is arranged to monitor the pressure in thedisposal collector (18) and to alert if the pressure exceeds apredetermined threshold pressure indicating that the disposal collector (18) needs to emptied or replaced.