DE1478858A1 - Torque control aid for power tools - Google Patents

Description

Dr. A. ULLRICH Dr. T. ULLRICH PATENT LAWYERS A ΛΤΟΟΠΟ

69 HEIDELBERG, Oohb * rostr Jl

Telephone: 2935 - Talagrpnmadratta: ULLPATENT

Desoutter Brothers Ltd.
The Hyde, Hendon, London N «W.9, ENGLAND

Torque control aids for power operated Tools

The invention relates to torque control tools for power tools, particularly, but not exclusively for pneumatically operated hand-held wrenches while the item of the invention consists of a hand-held power tool, in which the maximum, torque generated by the tool is automatically controlled.

The invention consists of a hand-held power tool in which the Tool head is driven by a motor via a worm or worm wheel and this is characterized is that the worm is in bearings for longitudinal movement against the action of a spring under the Reaction of the torque exerted by the tool and that this longitudinal movement is mounted is used to interrupt the drive when the torque reaches a predetermined value.

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The invention also relates to a hand-held power tool such as ben, in which the motor is operated pneumatically and the air supply to the motor is interrupted when the torque reaches a predetermined value.

In addition, the invention relates to a tool as described above, in which the air is drawn from the supply point passes through a snoring valve to the engine, which is forced to move in the opposite direction "to open the pressure of the air going to the engine by means of an air pressure controlled by a transfer valve operated to reduce the latter Interrupt air pressure when the torque reaches the predetermined value to close the snore valve achieved.

The accompanying drawing shows by way of example an embodiment of the invention in which the Fig. 1 shows a longitudinal section through the tool.

Pig. 2 is a partial cross-section, partly in elevation, by the tool at line 2-2 of FIG. 1, while

FIG. 3 shows a section on the line 3-3 according to FIG. 2

represents.

The tool shown contains a main part 1 and a handle part 2, firmly connected to the main part, the latter having a cylindrical housing 3 containing a motor 4 equipped with blades and a planetary gear 5 houses which is driven by the shaft 6 and which on the other hand drives the shaft 7,

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on which there is a worm 8 which is in engagement with the worm wheel 9. In the middle of Worm gear 9 is the hexagonal opening 10 for the engagement of the hexagonal head of a bolt or a nut which is attached to the tool.

The drive between the planetary gear 5 and the shaft 7 is done with the help of the grooves 7 a on the parts 7 b and 7 c, so that the shaft 7 extends longitudinally with respect to the part 7 b against the action the spiral spring 7 d can move on the puddles 7 e and 7 f.

The outer end of the shaft 7 rests on the ball 8 a when the tool is at rest, but under the reaction of the applied torque on the bolt or nut, the shaft 7 moves away from the ball 8 a a short distance and is axially supported in the needle roller bearing 8 b.

The handle 2 is equipped with a contact spring 15 with which the tool air line is connected is. The air supply to the tool is controlled by the ball valve 16, which is provided by the Trigger 17 is operated against the action of spring 19 with the aid of rod 18.

The air passes through the bore 20 in the handpiece down to the cavity 21 through the open Schnarohventil 30 in the passages 36 a and 36 b on each Side and parallel to valve 30 (see Fig. 2) in the cavity 39 at the rear end of the engine 4.

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At the same time, the air passes from the cavity 21 into the bore 22 through the filter 22 a and goes along the transverse bore 23 a and through the openings 26 a and 26 b into the sleeve 26 c, in which the transmission valve 25 operates and flows through the cross hole 27 a in the cylindrical space 29 at the end of the snoring valve 30. The combined effect of the spring 35 and the air pressure in the cavity under the snoring valve 30 overcomes the air pressure in the cavity 21 at the ψ Yentilkopf and the valve therefore remains open.

When the torque exerted on the nut or the bolt is so great that the shaft 7 moves in the longitudinal direction moves, it moves the rod 7 g and in this way the transfer valve 25 against the action the spring 24 and continues the movement until the opening 26 a is closed, with the result that the Air passage to space 29 below the snoring valve 30 is interrupted and at the same time when the Opening 26 a is closed, the space 29 via the annular space 26 d in the sleeve 26 c and the Opening 26 e to the annular groove 26 f opened,) and the air passes through radial, not shown Drill holes in the groove 26 g, from where it is blown into the atmosphere, e.g. through the hole 26 h.

The snore valve then closes as a result of the pressure of the air in the cavity 21 overcomes the resistance the spring 35 and the motor stops, even if the trigger valve in the handpiece is still open.

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The openings 26 a, 26 b and 26 e are formed in the sleeve 26 c, which is longitudinally movable with Help of the cam 42 a, which is on the flanged pin 42 d in the sleeve against the action of the arched Springs 42 c engages. The position of the sleeve can therefore be adjusted so that the opening 25a is closed at one of a number of different torque levels as required.

The cam 42 a is located on the hexagonal

nalen shaft 42 d and is connected with a button 42 e "

see with which the position of the cam is set to the required torque value. It pawls are provided for the button 42e to lock it in any of a number of different positions with the help of a spring-loaded ball in the indentations in the button intervenes.

In operation, it is only necessary to engage the hexagonal opening 10 on the nut or bolt to be fastened, put your hand around the handle and pull the trigger. As soon as the required torque is reached, the motor stops. ( The trigger is then released and the tool removed.

It can be seen that the worm 8 and the worm wheel 9 are designed to rotate in both directions, and the motor offers no resistance when the air supply is cut, and the head of the nut or the bolt is depressurized when the engine

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stops, and therefore no higher torque is achieved by holding the handle.

The value of the torque at which the tool is released on the head of the nut or bolt is determined by the setting of the value by the knob 42 e and not by the force developed by the motor. Consequently, if the pressure of the air supply to the tool drop and the motor at a low Should torque come to a standstill, the tool should not be removed until the engine is shut off the air supply is released as a result of the release of the trigger 17. However, the full torque required can can still be applied to the bolt by levering the handle by hand while the motor is through the reduced air pressure is kept at a standstill. When the full torque is reached, the transfer valve switches automatically exhausts and frees the motor and the tool rotates freely around the bolt.

Although the invention has been described in the present case with reference to a wrench, it goes without saying that the invention can also be applied to other tools and for other purposes, while details for carrying out the invention in practice can be changed without departing from the spirit of the invention is deviated.

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Claims (1)

Claims Hand-held power-operated tool in which the tool head is driven by a motor with the aid of a worm and a worm wheel, characterized in that the worm (8) is mounted in bearings for longitudinal movement gen the effect of a spring (7 d) under the Eeak " tion of the torque exerted by the tool is mounted and the longitudinal movement to the interruption of the drive is used when the torque reaches a predetermined value. 2 · Tool according to claim 1, characterized in that the motor is operated pneumatically and the air supply to the motor is interrupted when the torque reaches a predetermined value. 3. Tool according to claim 1 and 2, characterized in that the air flows through a snore valve (30) to the i engine, which is forced to open in the direction against the pressure of the air going to the engine with the aid of an air pressure that controlled by a transfer valve (25) and which is operated so that it interrupts the latter air pressure when the torque reaches the predetermined value to close the snore valve (30). 909813/0462 4 «tool after. Claims 1-3 » characterized in that the transfer valve (25) contains a valve lock which works in a sleeve (26 c) provided with openings (26 a, 26 b and 26 e) and adjustable in the longitudinal direction in order to set the torque value at which the air pressure is interrupted. 5. Tool according to claim 1-4, characterized in that the sleeve (26 c) is caused by a spring (42 c) to touch a cam (42 a) which is rotatable by a torque value adjustment knob (42 e ). 6. Tool according to claim 1-5, characterized in that the sleeve provided with openings (26 c) is moved by the movement of the screw (8) via an intermediate rod (7 g.) Which goes through a bore through the motor. 7. Tool according to claim 1-6j, characterized in that a cylindrical cavity (21) is provided below the snore valve (30) in which the tappet of the valve acts as a piston rod, and to which the latter air pressure is applied to the valve to be kept open while the tool is working and the air pressure is supported by a spiral spring in this cavity (21). 8. Tool according to claim 1-7, characterized in that it has a handle (2) at the end of the tool 909813/0462 is equipped opposite the head and has a contact spring (15) with which an air line is connected is, and that it has a valve operated with a trigger in the handle, which the influx of air from the contact spring to the motor of the tool controls. 909813/0462