DE3230989A1 - POWER TOOL - Google Patents

Description

HOEGER, STELLR ^ CNtV P> fWNEF? 2 3 Ο 9 8

PATENTANWÄLTE UHLANDSTRASSE 14 cD 7000 STUTTGART 1

A 45 290 b Applicant: Desoutter Limited k - 176 319 Edgware Road

August 19th Colindale

London / Great Britain

Power tool

The invention relates to a power tool with a housing, a lead screw, and a motor for driving the lead screw to a rotary movement and a spindle nut cooperating with the lead screw. Such Power tools are used, for example, as drilling machines or as machines for thread cutting used.

With certain power tools it can be very beneficial if it is possible to first advance the tool in rapid traverse up to the workpiece and only then to switch to the normal feed rate. This can be done during normal feed The tool can then be advanced at a feed rate determined by the spindle pitch.

In the case of a known tool, in which there is the possibility of working in rapid traverse, is the spindle nut is divided diagonally and its parts can be moved apart for quick axial movement to enable the lead screw. The two

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Spindle nut parts are then again, in engagement with brought the lead screw when normal feed rate is to be used. The known The tool or the known machine tool has two serious disadvantages. First of all it is difficult to return the split spindle nut after it has been lifted so that it works properly runs on the lead screw. In addition, the tool head inevitably has a large diameter, because this space is for the radial movement of the spindle nut parts and for their actuators must have. The large dimensions of the tool head make it difficult to attach other tools the immediate environment, so that the number of operations that can be carried out simultaneously on a workpiece is reduced.

Based on the state of the art and the problems outlined above, the object of the invention is based on specifying an improved power tool, which in rapid traverse and with normal feed rate can work and still be made relatively slim and works reliably.

This task is carried out with a power tool described type solved according to the invention in that the lead screw is part of a lead screw ! is the arrangement which is relative to the tool

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housing is movable in the axial direction that the spindle nut is adjacent to one end of a tubular Spindle nut holder is arranged in such a way

^m that they are secured against axial and radial movements

tj is that the spindle nut holder in the axial direction

Il device with respect to the tool housing between a

1 | front and a rear end position movable

is, and that drive devices are provided with the help of which the lead screw assembly together § with the spindle nut holder from the rear end

ff position can be moved into the front end position,

j§ and that locking devices are provided,

|; with the help of which the spindle nut holder with respect to

| f of the tool housing in. Its front. End position

\\ is releasably lockable.

The decisive advantage of the power tool according to the invention is that the spindle nut is constantly can remain in contact with the lead screw and that the diameter of the tool head is thus considerable can be smaller than in the known tool of the type described above.

In a preferred embodiment of a power tool according to the invention, the locking

■ νί facilities at least one, but preferably several

■: radial, in the circumferential direction at a distance from each other

',, \ openings seen in the spindle nut holder and

fif at a distance from one end of them. In

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each of the openings each have a locking element arranged from the tool housing in such a Is held that it protrudes radially inwardly beyond its associated opening, as long as the spindle nut holder is not fully extended to its front end position. In addition, the locking elements are captured by a support surface on the lead screw assembly, such that they radially are pressed outside when the spindle nut holder is in its outer end position, wherein the motor is turned on to the spindle assembly due to the interaction of the lead screw and to move the spindle nut towards the spindle nut. Act in their radially outer position the locking elements so with the tool housing together that they have an axial relative movement between the tool housing and the spindle nut holder, impede. According to the invention, the spindle motor is movable in the axial direction with the lead screw arrangement, while a pressure medium-actuated piston is preferably provided for driving the lead screw arrangement connected to the lead screw assembly.

At the. Working with the power tool according to the invention is based on an operating state in which the spindle nut holder is in its rear End position is a pressure medium, such as compressed air, effective on the piston to the engine and the

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Advance lead screw assembly and thus also the spindle nut and the spindle nut holder until the Spindle nut holder reached its end position. The motor, especially a compressed air motor / is then switched on / whereupon the motor and lead screw assembly with a speed corresponding to the lead screw pitch (and speed) move forward. Furthermore, the locking elements (at least one locking element is provided), such as e.g. balls, rollers or sliding segments, moved outwards by supporting surfaces of the lead screw arrangement, where they apply to the tool housing in such a way that the spindle nut holder is in its front end position is locked. Then, when an operation with the tool is completed, “the engine reversed, the locking elements can move back radially inward as soon as the support surfaces moved back behind them. The motor and lead screw assembly can now be quickly withdrawn together with the spindle nut and spindle nut holder be, for example by means of a return spring or by means of a pressure medium-actuated device until the spindle nut holder has reached its rear end position.

Further preferred configurations of the tool according to the invention are the subject matter of the subclaims.

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The invention is explained below with reference to drawings
explained in more detail. Show it:

Fig. 1 is a partial longitudinal section through the

front end of a preferred embodiment of a Kraftwexkzeugs
according to the invention at in their
front end position locked
Spindle nut holder and

Fig. 2 is a complete longitudinal section
by the power tool according to
Fig. 1 with spindle nut in its rear end position ;; <terhalterung.

In detail, Figs. 1 and 2 of the drawing show a %

Power tool with a housing, which has a rear ''},

ren part 11, a middle part 12 and a front \ '\

the part of which has 13. The housing parts 11 to 13 \ {

are arranged coaxially to one another. A socket 14 | .i <

connects the housing parts 11 and 12. The front K]

Housing part 13 and the middle housing part 12 are screwed U each other so that they tung in the axial RICH »n are mutually adjustable. A 0

[j Circlip 15 to prevent unintentional twisting or axial adjustment of the. Housing parts 12 _; , ;; 13 is prevented against each other. . "■

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υ! In the housing 10 is a tubular spindle nut

Ij bracket 16 in the axial direction between two end

i | Positions slidably supported. In one

ff end position (Eig. 2) is the bracket 16 with her

U rear end at the front end of the socket 14. In

ff the other end position (Fig. 1) is a shoulder

% 17 of the bracket 16 on a shoulder 18 of the front

I housing part 13.

I) Furthermore, a housing bushing 19 is located in the housing 10

1 with an outer toothing 20 slidably mounted

|| arranged with an internal toothing of the connecting

k, sleeve 14 cooperates, which serves as a slide bearing, and

I with an inner toothing 22 of the holder 16. The

II housing socket 19 encloses a compressed air motor 9,

■ if its rotor via a reduction gear 33 with a

I drive shaft 23 is connected, which is in bearings 24 in : | the housing sleeve 19 is mounted. With the drive IJ shaft 23 is connected to a lead screw 25 for rotation therewith. ff The lead screw 25 is at its front end to

ϊφ Mounting of a tool or a tool holder

: | for a tool such as a twist drill or

II a tap set up. The thread of the i | "Lead screw 25 interacts with the thread along a spindle M nut 26, which is in the front part of the hold 3 tion 16 between a snap ring 27 and a detachably attached ^ spindle nut cap 28 is disposed.

ψ The. Spindle nut 26 is against rotation with respect to

ft of the threaded spindle 25 secured, for example by

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cooperating eccentric parts on the spindle nut 26 on the one hand and on the holder 16 or the Cap 28 on the other hand.

As FIG. 2 shows, _{a piston 34 with a hollow piston rod 35 is connected to the rear end of the sub-assembly consisting of the housing bush 19 7,} the motor 9 / the drive shaft 23 and the lead screw 25. The piston 34 is received by a cylinder in the rear housing part 11 and held in its rear end position by a compression spring 8. The piston 34 moves forward when compressed air is supplied from a control unit 36 to the end of the cylinder on the left in the drawing. The motor 9 is supplied with the compressed air from the control unit 36 via a channel 37, the hollow piston rod 35 and a reversing valve 38 / which can be actuated by a pull rod 39. The interior of the piston rod 35 is connected to the channel 37 via openings 40 in the piston rod, but only then or only when the piston 34 has moved a little forward from its rear end position.

In the spindle nut holder 16 are adjacent to the rear end of the same several radial, in the circumferential direction openings 29 arranged at a distance from one another are provided. In this case, one of each opening 29 is Ball 30 is received, the diameter of which is greater than the depth of the associated opening 29.

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The front end 31 of the middle housing part 12 is conical, in such a way that the cone tip of the cone in question is behind the front one End of the middle housing part 12 lies. The front end of the housing sleeve 19 also has the outside a conical surface 32, with the apex of the corresponding cone, however, in front of the front end of the Housing sleeve 19 is located.

At the beginning of a work process, the holder 16 is in its rear end position with respect to of the tool housing 10. The conical surface 32 of the housing bushing 19 lies behind in the axial direction the openings 29 for receiving the balls 30. The balls 30 are in such a way on the tool housing 10 that they protrude inward in the radial direction via their associated openings 29.

When the piston 34 is pressurized, the subassembly moves with the elements 19, 9, 23 and 25 together with the spindle nut 26 and the holder 16 opposite the tool housing 10 quickly forward until shoulder 17 of the housing socket, the shoulder 18 of the front housing part 13 is captured. As the piston 34 moves forward, reaches the channel 37 via the openings 40 in connection with the interior of the piston rod 35, so that the Compressed air motor 9 starts up. The threaded spindle 25 now drives the spindle nut 26 with a through

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Pitch of the thread specified speed forward. At the same time, the housing sleeve 19 of of the threaded spindle 25 is pulled forward, the conical surface 32 in contact with the balls 30 towards the outside with the. conical end 31 of the middle housing part 12 presses, as shown in FIG. Through this the spindle nut holder 16 is in the axial direction set in relation to the tool housing 10. A control rod 41 on a cross head 43, which at the piston rod 35 is attached, a valve (not shown), which is attached to a Bracket 46 is attached and the valve delivers a pneumatic signal through flexible hose (not shown) to the control unit 36, which causes an exhaust port of the cylinder to open will. The piston 34 is consequently no longer acted upon by compressed air, as a result of which there is excessive wear the lead screw 25 and the screw nut 26 is avoided, and thereby ensures that the entire game is subject to a bias in one direction during a machining process. the Lead screw 25 now drives the tool into a workpiece to be machined, and accordingly the lead screw lead.

Torsional forces that take effect on the bracket 16 are transmitted to the housing bushing via the teeth 22 and 20 19 and from there transferred to the teeth of the connection sbuch se 14 on the tool housing 10 is attached.

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When a desired machining depth is reached, an adjustable screw (not shown) operates a valve element of the control unit 36 on the crosshead 43. This generates a signal to a piston 44 to move 35 to the rear in ein.Ventilkopf 45 at the rear end of the piston rod 44, whereby the The pull rod 39 and thus the reversing valve 38 can be moved backwards in order to reverse the actuation of the compressed air motor 9. The lead screw 25 now runs in the opposite direction and pulls the housing 19 afterwards at the rear, the speed being determined by the spindle pitch until the balls 30 above did! Conical surface 32 of the housing sleeve 19 can slide inward. This creates the lock for the spindle nut holder 16 solved. The one acting on the piston Return spring 8 now leads the sub-assembly n \ it of the housing 19 to hiriten very quickly back, the spindle nut 26 being brought into its starting position. During the quick repatriation the compressed air supply to the motor 9 is interrupted as soon as the openings 40 from the area o.es. Channel 37 get out. Then the transfer valve returns. 38 back to its original position.

When the spindle nut holder 16 is in its Locked position with respect to the tool housing 10 is, any play between the balls 30 and the associated contact surfaces are compensated by the front housing part 13 and the

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Locking ring 15 relative to the middle housing part 12 to the rear, rotates, whereby the distance between the shoulder 18 on the front housing part 13 and the conical end 31 of the middle housing part 12 is reduced will.

Instead of balls 30, rollers or sliding segments can also be used.

Instead of the spring 8, the piston could also be returned by means of compressed air.

Instead of the compressed air motor, an electric motor with associated cam switches could be used, which switch the motor on and off at the appropriate times. When using an electric motor, this would be mounted outside the housing 10 and coupled via a drive connection to a belt pulley, which would sit with an axial toothing on an associated toothing of the drive shaft for the lead screw. The drive connection could be formed by a toothed belt. In this case the motor and the pulley would be arranged in a fixed axial position and would not move forwards or backwards with the lead screw.

Furthermore, the rapid advance of the lead screw can not only take place by means of a piston / cylinder unit, but also, for example, with the help of a manually rotatable pinion, which is connected to a toothed rail combs on the jacket socket 19.

Claims (1)

32309 * 9 HOEGER, STEL-bRecH-r - & * P'a'RTNER PATENTANWÄLTE UHLANOSTRASSE 14C-D 7000 STUTTGART 1 A 45 290 b Applicant: Desoutter Limited k- 176 319 Edgware Road August 19, 1982 Colindale London / Great Britain Claims Power tool with a housing, a lead screw, a motor for driving the lead screw to a rotary movement and a spindle nut interacting with the lead screw, characterized in that the lead screw (25) is part of a lead screw arrangement which is movable relative to the tool housing (10) in the axial direction, that the spindle nut (26) is adjacent is arranged at one end of a tubular spindle nut holder (16) so that it it is secured against axial and radial movements that the spindle nut holder. (16) in axial direction with respect to the tool housing (10) between a front and a rear! End position is movable, and that drive devices (34) are provided with the help of which the lead screw assembly together with the spindle nut holder (16) from the rear end position is movable into the front end position, and that locking devices (29). -2- A 45 290 b k - 176 - 2 - 19th August 1982 31, 32) are provided, with the help of which the spindle nut holder (16) with respect to the V7erkzeuggehäuses (10) can be releasably locked in its front end position. 2. Power tool according to claim 1, characterized in / that the motor (9) in the axial direction is movable together with the lead screw assembly. 3. Power tool according to claim 1 or 2, characterized in that the drive devices have a pressure-medium-actuated piston (34) attached to the lead screw arrangement. 4. Power tool according to claim 3, characterized in that that the piston (34) is assigned a return spring (8), with the help of which he from a the front end position of the lead screw (25) corresponding to its rear position End position of the lead screw (25) associated end position can be returned. 5. Power tool according to claim 3, characterized in that that the piston (34) is part of a double-acting piston / cylinder unit a front and a rear end position. -3- A 45 290 b k - 176 - 3 - 19th August 1982 Power tool η i one of claims 1 to 5, characterized in that the locking devices have one or more radial ones in the circumferential direction comprise spaced apart openings (29) which are in the locker nut holder (16) are arranged at a distance from one end of which and in each of which a locking element (30) is arranged, which of the tool housing (10) is held in such a position that it is associated with its Opening (21) except when the locker nut holder is (16) is in its front end position, protrudes radially inward and through a support element (32) of the lead screw assembly can be detected in such a way that it is in its front End position of the spindle nut holder (16) can be moved radially outward, and that the motor through the interaction of the threads of the lead screw and the screw nut (26) can be switched on in order to move the lead screw arrangement in the direction of the spindle nut (26), wherein the at least one locking element (30) in its radially outer locking position in such a way cooperates with the tool housing (10) that an axial relative movement between the Tool housing (10) and the spindle nut holder (16) can be prevented. A. 45 290 b k - 176 - 4 - 19th August 1982 7. Power tool according to claim 6, characterized in that that the at least one locking element (30) is a ball. 8. Power tool according to claim 6, characterized in that the at least one locking element f? (30) is a roller. U 9. Power tool according to claim 6, characterized in that that the at least one locking element is a sliding segment. 10. Power tool according to one of claims 6 to 9, characterized in that the lead screw arrangement has an outer jacket sleeve (19) in the spindle nut holder (16) in the axial Direction is slidable, and that the at least one support element (32) by a annular conical surface (32) of the housing sleeve (19) is formed. 11. Power tool according to claim 10, characterized in that that the housing bushing (19) and the spindle nut holder (16) are provided on them Toothings (20, 22) are non-rotatably connected to one another. -5- A 45 230 b k - 176 - 5 - August 19, 1982 12. Power tool according to one of claims 1 to 11, characterized in that the spindle nut holder (16) and the tool housing (10) with assigned to one another, defining the front end position of the spindle nut holder (16) I shoulders (17, 18) are provided. i 13. Power tool according to claim 12, characterized f indicates that the at least one locking element \ (30) in its radially outer position to a Conical surface of the tool housing (10) can be applied is. 14. Power tool according to claim 13, characterized ■ ,: shows that the conical surface of the tool J housing (10) opposite the shoulder (18) of the same I is offset backwards. 1 15. Power tool according to claim 14, characterized ; draws that the distance between dar conical ί Surface of the tool housing (10) and the shoulder if (18) of the same is adjustable. H 16. Power tool according to one or more of the following f | Proverbs 3 to 15, characterized in that s | Valve devices (41) for interrupting the |! Pressure medium supply to propel the piston (34) % are provided, which can be activated as soon as -6- «· Ι 3230389 A 45 290 b k - 176 - 6 - 19th August 1982 the spindle nut holder is locked in its front end position. 17. Power tool according to one of the preceding claims, characterized in that reversing devices (44, 45, 39, 38) are provided, with the aid of which the motor (9) can be reversed after machining has been completed. 18. Power tool according to one of claims 3 to 17, characterized in that compressed air is provided as the pressure medium. 19. Power tool according to one of the preceding claims, characterized in that the motor is designed as a compressed air motor (9). -7-