This application claims priority under 35 U.S.C. ยง119 to patent application number DE 10 2013 209 173.7, filed on May 17, 2013 in Germany, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure relates to a hand power tool, comprising a drive spindle, a mechanical impact mechanism, which has an impact body having at least two drive cams, and comprising a spindle lock device, which has a spindle roller carrier, which is disposed on the drive spindle and on which at least two spindle rollers are disposed.
Such a hand power tool is known from EP 1 847 355 B1, this hand power tool having a mechanical impact mechanism that is provided with an impact body comprising two drive cams. This hand power tool has a spindle lock device, in which a spindle roller carrier provided with two spindle rollers is disposed on a drive spindle, which can be driven in rotation or percussively by the impact body when the hand power tool is in the normal or impact mode. In this case, when the hand power tool is in the normal mode, the impact body, via its two drive cams, transmits a torque to assigned output cams of the spindle roller carrier, which transmits this torque to the drive spindle via assigned driver arms.
A disadvantage of the prior art is that, in the case of such a hand power tool, there is an inefficient transmission of torque from the impact body to the drive spindle via the spindle roller carrier, since the output cams and the driver arms of the spindle roller carrier have differing radii in relation to a longitudinal central axis of the spindle roller carrier.
It is therefore an object of the disclosure to provide a new hand power tool, comprising a mechanical impact mechanism and a spindle lock device, with which, in the normal mode, it is possible to achieve an improved transmission of torque from an impact body, assigned to the impact mechanism, to a drive spindle of the hand power tool that is provided with a spindle roller carrier of the spindle lock device.
This problem is solved by a hand power tool, comprising a drive spindle, a mechanical impact mechanism, which has an impact body having at least two drive cams, and comprising a spindle lock device, which has a spindle roller carrier, which is disposed on the drive spindle and on which at least two spindle rollers are disposed. The spindle lock device is connected via a coupling member to the mechanical impact mechanism, which is disposed between the impact body and the spindle roller carrier, in the axial direction of the drive spindle, and which is realized to effect rotary driving of the spindle roller carrier, upon rotary driving by the impact body, when the hand power tool is in the normal mode.
The disclosure thus makes it possible to provide a hand power tool, comprising a mechanical impact mechanism and a spindle lock device, with which, through use of the separate coupling member disposed between the impact body and the spindle roller carrier, it is possible to achieve an improved transmission of torque from the impact body of the impact mechanism to the drive spindle provided with the spindle roller carrier, in the normal mode. Moreover, the use of the separate coupling member does not require any increase in the dimensions of the hand power tool, which can therefore be of a compact configuration.
According to one embodiment, the coupling member has at least two output cams, which are realized to be driven percussively by the drive cams of the impact body when the mechanical impact mechanism is in the impact mode.
Thus, when the hand power tool, or the mechanical impact mechanism, is in the impact mode, percussive driving of the coupling member by the impact body is easily achieved.
Preferably, the coupling member has at least one opening, in which a pin-type driver member, provided on the spindle roller carrier, engages to enable rotary driving of the spindle roller carrier, upon rotary driving of the coupling member by the impact body, when the hand power tool is in the normal mode.
A driving torque that is transmitted from the impact body of the mechanical impact mechanism to the coupling member when the hand power tool is in the normal mode can thus be transmitted in a safe and reliable manner from the coupling member to the spindle roller carrier. In this case, an improved transmission of torque from the impact body to the drive spindle can be achieved, in particular, in that a radius from an assigned longitudinal central axis of the spindle roller carrier to the pin-type carrier member corresponds, at least approximately, to a radius from an assigned longitudinal central axis of the coupling member to the output cams.
Preferably, provided on the coupling member there are at least two drivers, which are disposed on the outer circumference of the spindle roller carrier, to enable at least one of the at least two spindle rollers to be driven, upon rotary driving of the spindle roller carrier by the coupling member, when the hand power tool is in the normal mode.
Thus, when the hand power tool is in the normal mode, uncontrolled blocking of the at least one of the at least two spindle rollers can be prevented in an effective manner.
Preferably, the spindle roller carrier is disposed on the drive spindle in a rotationally fixed manner.
A transmission of torque from the spindle roller carrier to the drive spindle is thus easily achieved.
According to one embodiment, the spindle roller carrier with the at least two spindle rollers is seated so as to be rotationally movable in a blocking member, which is realized to fix the at least two spindle rollers to the spindle roller carrier, in the radial direction of the drive spindle.
The disclosure thus makes it possible to provide a hand power tool in which the spindle rollers are safely and reliably fixed to the spindle roller carrier.
Preferably, on its outer circumference, the spindle roller carrier has an assigned guide curve for each of the at least two spindle rollers.
The spindle rollers can thus be guided along the respectively assigned guide curve, in dependence on the respective operating mode of the hand power tool, i.e. normal or impact mode, in respectively assigned operating positions.
The assigned guide curve is preferably realized to enable at least one spindle roller to be clamped between the spindle roller carrier and the blocking member, when the spindle lock device is in the spindle lock mode.
It is thus easy to achieve blocking of the drive shaft relative to the tool housing of the hand power tool, when the hand power tool, or the spindle lock device, is in the spindle lock mode.
According to one embodiment, the spindle lock device has at least four spindle rollers and, when the spindle lock device is in the spindle lock mode, at least two of the at least four spindle rollers in each case prevent a rotation of the spindle roller carrier relative to the blocking member.
The disclosure thus makes it possible to provide a hand power tool having a robust and stable spindle lock device, with which blocking forces that occur in the spindle lock mode are in each case distributed to at least two spindle rollers, such that overloading of the spindle rollers can be prevented in an effective manner.
The blocking member is preferably annular in form, and connected to a tool housing of the hand power tool in a rotationally fixed manner.
The blocking member can thus be easily fixed in the tool housing.
The disclosure is explained in greater detail in the description that follows, with reference to exemplary embodiments represented in the drawings, wherein:
According to one embodiment, for the purpose of supplying electrical power independently of a mains power supply, the hand power tool 100 can be connected mechanically and electrically to a battery pack 130 and, by way of illustration, can be actuated, i.e. switched on and off, via a hand switch 128. The hand power tool 100 is realized, by way of example, as a battery-operated rotary impact screwdriver, and has a mechanical impact mechanism 170. The latter, by way of example, is a rotary, or rotational, impact mechanism, which generates percussive-type rotary impulses at high intensity and transmits them to an output shaft 124. It is pointed out, however, that the present disclosure is not limited to battery-powered rotary impact screwdrivers but, rather, may be used with various hand power tools that have mechanical impact mechanisms, in particular rotational, or rotary, impact mechanisms, irrespective of whether the hand power tool can be operated electrically, i.e. independently of a mains power supply, by means of a battery pack, or in dependence on a mains power supply, or non-electrically.
The output shaft 124 is, for example, a drive spindle that is realized to drive a tool receiver 150 and on which the tool receiver 150 is disposed. The latter is realized to receive insert tools, and may be formed on to the drive spindle 124 or connected to the latter as an attachment. Preferably, the tool receiver 150 can be connected both to an insert tool 140 having an external polygonal coupling 142, and to an insert tool having an internal polygonal coupling, e.g. a socket wrench. The insert tool 140, by way of example, is realized as a screwdriver bit having the external polygonal coupling 142 realized, by way of illustration, as a hexagonal coupling, which is disposed in a suitable hexagonal internal receiver of the tool receiver 150. Such a tool receiver and such a screwdriver bit are sufficiently well known from the prior art and do not constitute subject-mater of the present disclosure, such that, to keep the description concise, they are not described in detail here.
According to one embodiment, a spindle lock device 200, described in greater detail below with reference to
The spindle lock device 200 is disposed between the mechanical impact mechanism 170 and the tool receiver 150, in the axial direction of the drive spindle 124, and serves to center and block the drive spindle 124 when the drive motor has been switched off. The functioning of spindle lock devices is sufficiently well known from the prior art, such that, to keep the description concise, the functioning of the spindle lock device 200 is not described in detail here.
The mechanical impact mechanism 170, by way of example, has an impact body 272, which is seated so as to be rotationally movable and longitudinally displaceable, at least partially, in the output housing portion 112, and which has at least two drive cams 274, and is spring loaded in the direction of the drive spindle 124. An exemplary mechanical impact mechanism, by which the mechanical impact mechanism 170 can be realized, is described in DE 20 2006 014 850 U1, to which express reference is made here, and the teaching of which is to be understood to be part of the present description, such that, to keep the description concise, the mechanical impact mechanism 170 need not be described in detail here.
According to one embodiment, the mechanical impact mechanism 170 is connected to the spindle lock device 200 via a coupling member 275. This coupling member 275, by way of illustration, is assigned both to the mechanical impact mechanism 170 and to the spindle lock device 200, and is realized as a separate component disposed between the impact body 272 of the mechanical impact mechanism 170 and a spindle roller carrier 230 of the spindle lock device 200, in the axial direction of the drive spindle 124.
The spindle roller carrier 230 has a central opening 234, is disposed on the drive spindle 124, which engages in the latter by means of a connecting portion 224, and is preferably connected to the drive spindle in a rotationally fixed manner, e.g. by means of a press fit or a form closure connection on the connecting portion 224. Disposed on the spindle roller carrier 230, e.g. on its outer circumference, there are at least two, and preferably four or more, spindle rollers 240, of which only two spindle rollers 242, 244 are shown, by way of example, in
The pin-type driver members 238 preferably extend at least approximately parallelwise in relation to each other and in each case out from radial extensions 239, provided on the outer circumference of the spindle roller carrier 230, which is at least substantially annular in form, in the direction of the coupling member 275. At least two, and preferably four, guide curves 232, 233 (and 532, 534 in
The coupling member 275 is preferably realized, at least, to effect rotary driving of the spindle roller carrier 230 upon rotary driving by the impact body 272, when the hand power tool 100 of
In addition, provided on the coupling member 275 there are preferably at least two drivers 277 (and 577 in
According to one embodiment, the spindle roller carrier 230 with the spindle rollers 240 is seated so as to be rotationally movable in a blocking member 250, which is realized, at least, to fix the spindle rollers 240 to the spindle roller carrier 230, or to the guide curves 232, 233 (and 532, 534 in
The blocking member 250 is preferably annular in form, and connected to the tool housing 110 of the hand power tool 100 of
In an example of mounting of the spindle lock device 200 in the output housing portion 112, an annular washer 260 is preferably first positioned on the second annular shoulder 214, inside the output housing portion 112, and the blocking member 250 is then pushed into the inside of the output housing portion 112, against the first annular shoulder 216 and the annular washer 260. The spindle roller carrier 230 is then disposed on the inner circumference 258 of the blocking member 250, and the connecting portion 224 of the drive spindle 124 is pressed into the opening 234 in the spindle roller carrier 230, from the axial end of the output housing portion 112 that faces toward the annular washer 260. In a further step, the spindle rollers 240 are disposed on the outer circumference of the spindle roller carrier 230, and the coupling member 275 is coupled to the spindle roller carrier 230 in such a manner that its drivers 277 (and 577 in
According to one embodiment, at least one, and preferably three longitudinal webs 355, for example spaced apart equidistantly from each other, are disposed on the inner circumference 312 of the output housing portion 112. These longitudinal webs, as viewed in the radial direction of the blocking member 250, engage with a predefined play in holding grooves, which are realized, as described with reference to
As the result of a driving torque being applied to the spindle roller carrier 230 out from the coupling member 275, e.g. in the direction of an arrow 499, the hand power tool 100 of
According to one embodiment, in the case of the rotary driving of the spindle roller carrier 230, the coupling member 275 is rotated relative to the latter in such a manner that the drivers 277, 577 block at least one, and preferably two, of the spindle rollers 242, 244, 342, 344 in the seating regions of their assigned guide curves 233, 232, 534 and 532, respectively. For example, the driver 577 blocks the spindle roller 344 in the seating region 432 of the guide curve 532 by means of a blocking face 599. At least one, and preferably two, more of the spindle rollers 242, 244, 342, 344 are blocked in the seating regions of their assigned guide curves 233, 232, 534 and 532, respectively, by the rotation of the spindle roller carrier 230. In
Number | Date | Country | Kind |
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10 2013 209 173.7 | May 2013 | DE | national |