GB2497197A - Power Handtool with Braked Transfer of a Stored Tool into a Tool Mount - Google Patents

Abstract

A power handtool comprises a tool casing and a tool mount 200 with a receptacle 201 for a tool 101. The tool 101 is initially stored in a tool change magazine which comprises at least one chamber for tool storage. This chamber is alignable with the receptacle 210 to allow the transfer of the tool 101. Braking means 280 are provided for braking the movement of the tool 101 during transfer between the chamber and the receptacle 210, which may be to prevent the tool 101 from slipping out from the distal end of the receptacle 210. The braking element 280 may comprise a resiliently deformable region, which may be an elastomer, for example, rubber. The braking element may comprise a sleeve-shaped region and hooked end portion 289 for exerting frictional force on the tool 101. The hooked end portion 289 may define a frictional region 285 which is at least partially annular with an inner diameter 294 smaller than the outer diameter 296 of the tool and may also be smaller that the inner diameter 292 of the receptacle 201.

Description

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POWER HANDTOOL WITH BRAKED TRANSFER OF A STORED TOOL

iNTO A TOOL MO UNT The present invention relates to a power handtool and has particular reference to a handtool in which braked transfer of a tool to a tool mount takes place.

A power handtool is known from DE 10 2006 059 688 Al. which comprises a tool change magazine which is rotationally movably mounted in an associated tool housing and which is provided with a plurality of tool chambers storing different tools, the magazine being rotatable about an axis of rotation into different tool change positions. In these tool change positions a respective one of the tool chambers is oriented in ahgnment with an associated toot mount so that a tool in the chamber can be pushed by a rod-shaped push element, which is arranged in the tool housing to be displaceable, into the tool mount and back out of the tool mount into the tool change magazine.

It is disadvantageous with the prior art handtool that a comparatively forceful pushing of a tool from the tool chamber into the tool mount by an impact-like actuation of the push-over element by a user can lead to slipping or pushing of the tool out of the tool mount. This can lead to damage of the tool and/or to injury of the user of the power handtool, as well as to loss of convenience in use of the power handtool.

It is therefore an object of the invention to provide a power handtool with a tool change magazine and an associated tool mount, in which slipping or pushing of the tool out of the tool mount when the tool is pushed from the tool change magazine into the tool mount can be effectively prevented.

According to the present invention there is provided a power handtool with a tool mount.

which is constructed for reception of a tool and has an internal receptacle and which is provided at an associated tool casing, in which a drum-like tool change magazine with at least one tool chamber for storage of the tool is arranged, the tool chanter being alignable with the internal receptacle so as to enable pushing of the tool from the tool chamber into the receptacle or from the receptacle over into the tool chamber and braking means being provided for braking the tool during pushing of the tool from the tool chamber into the internal mount.

Thus, slipping or pushing of the too) out of the too) mount during pushing of the tool from the magazine into the mount may be able to be securely and reliably prevented by braking of the tool during this transfer.

The braking means is preferably constructed for the purpose of preventing slipping of the tool out of an axial end, which is remote from the tool chamber, of the receptacle when the tool is pushed from the tool chamber into the receptacle. Provision of a power handtool is thus made possible in which a possible risk of injury for a user during pushing of the tool from the tool magazine into the mount are at least reduced.

For preference, the braking means comprises a brake element which is resiliently deformable at least in a region. This thus repreents a simple and uncomplicated brake device.

The brake element is preferably constructed to be sleeve-shaped at least in a section.

such a brake element being rapidly mountable and inexpensive.

In one form of embodiment the brake element can have a hook-shaped end region for generating a braking friction force at the toot. This results in a simple and constructionally stable brake element.

The hook-shaped end region is preferably constructed for the purpose of generating a spring force, which brakes the toot, by a resilient deformation during pushing of the tool into the hook-shaped end region. Functioning of the brake element in this way means that the element can be of particularly robust and operationally reliable. The hook-shaped end region can have an at least approximately annular friction region with an inner diameter smaer than an outer diameter associated with the tool, which thus enables transmission of a predetermined friction force from the annular friction region to a tool in simple mode and manner during pushing of the tool from the magazine into the mount. The annular friction region preferably has an inner diameter smaller than an inner diameter associated with the receptacle. Consequently, the predetermined friction force during pushing of the toot from the magazine into the mount can be transmitted securely and reliably from the annular friction region to the tool.

The friction region is preferably arranged at a predetermined spacing from an axial end, which is remote from the tool chanter, of the receptacle. A reduction in an effective friction force exerted on the tool during transfer of the tool from the mount into the magazine can thus be achieved.

The braking element preferably comprises an elastomer, particularly rubber. This feature contributes to provision of a stable and inexpensive braking element.

A preferred embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a schematic, partly sectioned side view of a power handtool with a drum-like tool change magazine and a tool mount; Fig. 2 shows a partly sectioned side view of the tool mount of Fig. 1 with a brake device as in the case of a handtool embodying the invention; Fig. 3 shows a sectional view of the tool mount of Ag. 2 with a tool arranged therein; and Fig. 4 is a side view of the tool mount and tool of Fig. 3.

Referring now to the drawings there is shown in Fig. I, by way of example, a handheld, motor-driven power tool 100 which has a tool casing Ill in which a drum-like tool change magazine 120 is arranged to be rotatable about an axis 103 ci rotation. The magazine is, by way of example, of hollow-cylindrical shape with an annular circumferential body 102 in which a plurality of tool chambers is provided. Insert tools, for example, can be arranged in the tool chambers, in which case different tools can be provided in the chambers. For the sake of clarity, only a single tool chamber -denoted by 199 -is shown in Fig. 1. An insert tool 101 is arranged in this chamber 199.

The power handtool 100 is constructed, by way of example only, as a so-called bit screwdriver for handling screwdriver bits. However, it is to be' noted that the present invention is not restricted to bit screwdrivers of that kind, but rather can be used in all power tools in which a drum-like tool change magazine rotatable about a longitudinal axis can find use regardtess of whether or not screwdriver bits or other exchange objects can be stored in the magazine or whether or not the power handtool is handheld.

In one form of embodiment a tool mount 200 for reception of the tool 101 is arranged at the too) housing 111 and is rotatable about an associated longitudinal or rotational axis 188. The tool mount 200 is, by way of example, coupled by a transmission toothing 106 with a drive output shaft 119 of a transmission 112 for driving the tool 101, which transmission by way of example is arranged in a housing 114. For this purpose, a drive gearwheel 179 can be provided at the drive output shaft 119 and co-operate via the transmission toothing 106 with a drive output gearwheel 202 provided at the tool mount 200. The drive output shaft 119 is set into rotational movement by, for example, a motor shaft 177 of a drive motor 107 which is coupled with the transmission 112 and which, by way of example, is arranged in an associated motor housing 117, wherein the motor housing 117 and the transmission housing 114 are1 byway of example, arranged and fixed in place in the tool casing 111.

By way of illustration, the tool mount 200 has a tool receiving section 211, which is of hollow-cylindrical shape and in which is formed, for example, an internal receptacle 210, which is provided with a rotation entraining profile 212 (see Fig. 2), for example an internal polygonal profile, and into which the tool 101 -provided with, for example, a corresponding external polygonal coupling 151 -can be pushed from the tool chamber 199 for rotationally secure connection with the tool mount 200.

A push-ever mechanism 110 is provided for pushing the tool 101 from the tool chamber 199 into the receptacle 210 of the tool mount 200 and from the receptacle 210 into the chamber 199. This mechanism comprises, for example, a push-over element 108 which is cons!ructed as, for example, a pushrod 109, which is actuable by way of an actuating element 122 and which is guided in a guide 116 provided at the transmission housing 114.

The axial end of the pushrod facing the tool 101 can be constructed to be magnetic for magnetic connection with the tool 101. The actuating element 122 is, by way of illustration, axiafly displaceable in an opening 112, which is provided at th! tool housing 111, parallel to the axis 188 of rotation of the mount 200.

In the case of a tool change, the magazine 120 is rotated about the axis 103 of rotation into a tool change position in which, for example, the chamber 199 with the tool 101 is oriented in alignment with the mount 200, in particular the receptacle 210 thereof. The actuating element 122 is then pushed, in the direction of an arrow 167, in the opening 112

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from its rear axial setting frito a front axial end setting in which the pushrod 109 extends through the tool chamber 199 and the tool 101 is located in the receptacle 210 of the mount 200 and blacked against return movement. For pushing the tool 101 out of the mount 200 into the chamber 199 the actuating element 122 is then axially drawn back in the opening 112 in a direction opposite to the arrow 16? untH in its rear axial end setting.

The mode of function and construction of the power handtool 100 are, in principle, already known from DE 10 2006 059 688 Al1 which in addition describes, for example, adjusting means for rotating the magazine 120 about the axis 103 of rotation to enable alignment of the chamber 199 with the mount 200. Accordingly, reference can be made to the disclosure of DE 10 2006 059 688 Al for further construction details.

Fig. 2 shows the tool mount 200, which is rotatable about the axis 188 of rotation and is provided with the tool mount section 211 of hollow-cylindrical shape, in the case of pushing of the tool 101 from the chamber 199 in the direction of an arrow 267 into the mount 200.

For simplification, merely the tool 101 and the tool mount 200 are shown. This has, by way of illustration, The drive output gearwheel 202 of Fig. 1 in the region of a first axial end 201. The rotational entrainirtg profile 212, for example an internal polygonal profile, of the receptacle 210 is formed in the region of an opposite, second axial end 203 for rotationally secure reception of the external polygonal coupling 151 of the tool 101.

By way of ithistration, the tool mount 200 goes over in the region of a first shoulder 217 from the gearwheS 202 into a first narrowed region 216, which at a second shoulder 215 goes over into the tool mount section 211. A roller bearing 270, which can be a needle roller bearing, for rotational mounting of the too) mount 200 in the tool casing 211 is arranged on the tool mount section 211, The roller bearing 270 is, for example, fixed between the first nan-owed region 216 and a blocking disc 260 to be axially immovable.

The blocking disc 260 is in turn blocked in axial direction of the tool mount 200 by a securing ring 250, for example a C-ring, fastened in an annular groove 214 formed at the tool mount section 211.

A brake device 280 for braking the tool 101 during pushing of the tool 101 from the chamber 199 into the receptacle 210 is provided in the region between the securing ring 250 and the second axial end 203 of the tool mount 200. The brake device 280 is preferably constructed for the purpose of preventing slipping or pushing of the tool 101 out of the second axial end 203 during transfer of the tool 101 the receptacle 210.

The brake device 280 comprises, for example, a brake element 251, which is resiliently deformabie at least in a region and is constructed to be sleeve-shaped at least in a section and which preferably comprises an etastomer, particularly rubber, at least in a region. In one form of embodiment the brake element 281 is of cap-shaped construction in the form of a rubber cap and, for example, pushed onto the tool mount section 211 in the region of the axial end 203 of the tool mount 200. The brake element 281 has a collar-like section 282, which faces the securing ring 260 and which, for example, bears against the securing ring 260. in order to prevent slipping of the brake element 281 of the tool mount section 211 the brake element 281 has a ring-like projection 286 which is formed at its inner circumference and which engages in an annular groove 218 provided at the outer circumference of the toot mount section 211.

The described annular projection 286 and annular groove 218 are merely by way of example and do not in any way restrict the invention. The brake element 281 can be fixed to the outer circumference of the tool mount section 211 in any desired mode and manner, for example, by mutually associated detent lags and depressions, by detent Jugs engaging in corresponding openings, etc. In addition, it is possible to use permanent connections such as, for example, glueing or welding.

The brake element 281 has at its axial end region remote from the collar-like section 282 a passage opening 284 for the tool 101, through which passage opening the tool 101 engages after pushing into the receptacle 210 and on into a tool operating position. In the region of this passage opening 284 the brake element 281 has, by way of illustration, a hook-shaped end region 289 for exerting a braking frictional force on the tool 101 during pushing of the tool 101 into the passage opening 284 as a consequence of transfer of the tool 101 to the receptacle 210.

The hook-shaped end region 259 is preferably formed from an elastomer, particular rubber, and serves the purpose of generating a spring force, which brakes the tool 101, by resilient deformatian during pushing of the tool 101 into the passage opening 284 and thus into and through the hook-shaped end region 289. For that purpose, the hook-shaped end region 289 has an at least approximately annular friction region 285 with an internal diameter 294 not only smaller than an external diameter 296 of the tool 101, but also smaller than an internal diameter 292 of the receptacle 210.

However, it is to be noted that the friction region 285 is of annular construction merely by way of example and different designs of this region are possible, for example, a plurality of hook-shaped friction arms provided in the end region 289, etc. The hook-shaped end region 259 is bent over in the direction of the tOol mount section 211. In other words, the hook-shaped end region 259 is constructed in such a manner as to engage around the axial end 203 of the tool mount section 211 in the case of complete pushing onto the tool mount section 211. However, for preference. the friction region 285 of the hook-shaped end region 289 is arranged at a predetermined spacing 291 from the axial end 203 of the tool mount 200 so that that the end region 289 does not engage around the axial end 203 with precise fit. This spacing 291 serves the purpose of at least reducing an effective frictional force, which is exerted on the tool 101 when the tool 101 is pushed from the tool mount 200 back into the magazine 120, by comparison with a friction force effective during pushing-over into the tool mount 200.

Fig. 3 shows the tool mount 200 and tool 101 after pushing of the latter into the receptacle 210 of the tool mount 200, in the rotational entraining profile 212 of which the external polygonal coupling 151 is held to be rotationally secure after the transfer. The tool 101 is thus arranged in the tool operating position in which the annular friction region 285 of the brake element 281 engages, by way of Thustration, in a circumferential groove 301 provided at the outer circumference of the external polygonal coupling 151. The functioning of the brake element 281 during pushing-over of the tool 101 into this tool operating position is described below.

During pushing-over into the tool mount 200 with use of the pushrod 109 the tool 101 is pushed through the passage opening 284 of the brake element 281 so that the annular friction region 285 thereof comes into engagement with the tool. The friction region 285 can thus exert a predetermined braking frictional force on the tool 101. In addition, the tool 101 displaces the friction region 285 in an axial direction away from the tool mount 200 and produces a radially outwardly directed resilient deformation of the hook-shaped end region 289, in which case the friction region 265 is stretched at least in a section in radiafty outward direction. Throu9h this stretching and the resilient deformation of the hook-shaped end region 289 a braking spring force is applied to the tool 101, which amplifies

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the predetermined friction force. On attainment of the tool operating position the annular friction region 285 then engages in the circumferentia! groove 301 at the outer circumference of the coupling 151, so that the tool 101 is securely retained in the tool mount 200 even in operation of the power handtool.

On transfer from the tool opelating position into the tool change or storage position, i.e. on pushing of the tool 101 from the tool mount 200 into the tool chamber 199 of Fig. 1, the tool 101 is drawn by the pushrod 109 out of the receptacle 210 in the direction of the drive output gearwheel 202. In that case, the annular friction region 285 can, due to the spacing (291 in Fig. 2) from the tool mount section 211, move in the direction thereof, in which case an approximately radially inwardly directed resilient deformation of the hook-shaped end region 289 takes place and the friction force and spring force applied to the tool 101 can thus be reduced.

Fig. 4 shows the tool mount and tool of Fig. 3 in side view for clarification of the cap-like design of the brake element 281. As shown in Fig. 2, this is pushed at least in a section onto the outer circumference of the tool mount section 211 of the tool mount 200.

Claims (1)

1. <claim-text>CLAIMS1. A power handtool comprising a tool casing, a tool mount arranged at the casing and having a receptacle for a tool, a tool change magazine arranged in the casing and having at least one chamber for storage of the tool, the chamber being alignable with the receptacle to permit transfer of the tool from the chamber to the receptacle and from the receptacle to the chamber, and braking means for braking movement of the tool during transfer from the chamber to the receptacle.</claim-text> <claim-text>2. A power handtool according to claim 1, wherein the braking means is arranged to prevent the tool from slipping out of the receptacle at an end thereof remote from the chamber during transfer from the chamber to the receptacle.</claim-text> <claim-text>3. A power handtool according to claim or claim 2, wherein the braking means comprises a brake element resiliently deformable at least in a region.</claim-text> <claim-text>4. A power haridtool according to claim 3, wherein the brake element is sleeve-shaped at least ri part.</claim-text> <claim-text>5. A power handtoot according to claim 3 or claim 4, wherein the brake element has a hooked end portion for exerting a braking frictional force on the tool.</claim-text> <claim-text>6. A power handtool according to claim 5, wherein the hooked end portion is resiliently deformable by the tool on movement thereof into the hooked end portion, the braking frictional force being provided by the resilient deformation.</claim-text> <claim-text>7. A power handtool according to claim S or claim 6, wherein the hooked end portion defines a friction region which at least in part is substantially annular with an inner diameter smaller than a given outer diameter of the tool.</claim-text> <claim-text>8. A power handtool according to claim 7, wherein the inner diameter is smaller than an inner diameter at the receptacle.</claim-text> <claim-text>9. A power handtool according to claim 7 or claim 8, wherein the friction region is arranged at a spacing from an end of the receptacle remote from the chamber.</claim-text> <claim-text>10. A power handtoal accordThg to anyone of daims 3 to-9, wherein the brake &ernetit comprises an elastomer.I I. A power handtool according to claim 10, wherefrt the elastomer is rubber.</claim-text>