Attachment part of a driven tool, driven tool and system

Abstract

Attachment part of a driven tool (1) for a driven tool, comprising: - an elongated housing (3) with an upper housing part (3a) and a lower housing part (3b) connected to the upper housing part (3a), - an input gear (9) configured to be connectable to an output shaft of a driven tool, the input gear (9) being arranged at a first end of the housing (3), - an output gear (11) having an output interface (11a), wherein the output gear (11) is arranged at a second end of the housing (3), - a first intermediate gear (13a) arranged within the housing (3) and configured to transmit the torque of the input gear (9) to the output gear (11), the first intermediate gear (13a) being rotatably mounted on a first intermediate gear shaft (15a), - at least one torque sensor (19) configured to detect radial forces acting on the first intermediate gear shaft (15a) in order to thereby obtain a measure of the torque at the output gear (11), and - an electronics unit configured to receive measured values ​​from the torque sensor (19) and adapted to transmit the measured values ​​to a control unit of a power tool which controls the operation of the power tool.

Description

[0001] The present disclosure relates to a power tool attachment part for a power tool.

[0002] Power tool attachments are generally used in confined spaces where it is impossible to reach a bolt or nut of the fastener being tightened with a conventional power tool. A power tool attachment is also known as a crowfoot attachment, front-end attachment, or offset attachment.

[0003] A power tool attachment comprises a plurality of gears that transmit rotary motion from an input gear to an output gear. The gears are generally arranged in a row, tooth to tooth, within an elongated housing.

[0004] The torque in a power tool is generally measured by a transducer located within the power tool. However, the internal measurement within the power tool may not provide an accurate measurement of the torque experienced by the power tool attachment attached to the power tool.

[0005] EP3388199 discloses a screwing device with a confined-space attachment connected to the screwing device. The confined-space attachment has helical gears equipped with angled teeth. The confined-space attachment includes a torque transducer configured to measure the torque of the gear arranged adjacent to the output gear. The torque measurement is based on the axial movement of the helical gear, and the transducer uses a load cell to determine the torque.

[0006] The helical gear structure is required to perform torque measurements. However, there are tight-space attachments that use other gear designs, such as spur gears with straight teeth.

[0007] The aim of the present disclosure is to provide an attachment part which solves or at least mitigates problems of the prior art.

[0008] Therefore, a power tool attachment for a power tool is provided, comprising: an elongated housing having an upper housing portion and a lower housing portion connected to the upper housing portion; an input gear configured to be connectable to an output shaft of a power tool, the input gear being disposed at a first end of the housing; an output gear having an output interface disposed at a second end of the housing; a first intermediate gear disposed within the housing and configured to transmit the torque of the input gear to the output gear, the first intermediate gear being rotatably mounted on a first intermediate gear shaft; and a torque sensor configured to detect radial forces acting on the first intermediate gear shaft.in order to obtain a measure of the torque at the output gear.

[0009] The torque sensor is thus configured to detect and measure radial forces acting on the first intermediate gear shaft when torque is transmitted via the first intermediate gear to the output gear. In this way, correct torque measurement can be achieved regardless of the tooth configuration of the first intermediate gear, the input gear, the output gear, and any additional intermediate gears. All gears can therefore be provided with straight teeth, i.e., so-called spur gears. This offers an important advantage, as such spur gears are considerably simpler and cheaper to manufacture than the helical gears with oblique teeth required in previous technology. However, the radial force detection also allows the gears to have any other suitable gear configuration, such as helical gears, if this would be advantageous for other reasons.

[0010] The torque sensor can be configured to measure the radial deformation of the first gear shaft. Such radial deformation can be accurately determined using proven and simple components such as piezoelectric elements and strain gauges.

[0011] The first intermediate gear can preferably mesh with the output gear. This allows the torque to be measured close to the actual output torque, allowing a correct output torque value to be easily calculated.

[0012] The first intermediate gear shaft may be hollow, and the torque sensor may be housed in the first intermediate gear shaft.

[0013] The torque sensor may comprise a piezoelectric element.

[0014] Otherwise, or in combination, the torque sensor may include a strain gauge.

[0015] The attachment of a power tool may further include a number of second intermediate gears disposed within the housing and configured to transmit the torque of the input gear to the output gear. By selecting the number of intermediate gears, the length of the attachment can be adapted to different applications.

[0016] The input gear, the output gear and the intermediate gear or gears may be spur gears.

[0017] Each intermediate gear can be arranged on the respective intermediate gear shaft by means of needle bearings.

[0018] The power tool attachment may further comprise an electronics unit configured to receive measured values ​​from the torque sensor.

[0019] The electronics unit can be configured to drive the torque sensor. For example, the electronics unit can comprise a battery or be configured to be connected via wires to the drive electronics of a power tool or to a control unit of a power tool.

[0020] The electronics unit may be configured to process the measured values. The electronics unit may therefore include a processing circuit configured to process the measured values, for example, to determine the torque based on the measured values ​​of the radial forces acting on the first intermediate gear shaft.

[0021] The electronics unit can be configured to transmit the measured values ​​to a control unit of a driven tool.

[0022] According to one embodiment, the attachment part of a driven tool is a narrow space attachment.

[0023] Further features and advantages of the present disclosure will become apparent from the figures and the detailed description of the embodiments shown.

[0024] In the following detailed description, reference is made to the attached drawings, of which: Fig. 1 shows a perspective view of an example of an attachment for powered tools; Fig. 2 an exploded view of the attachment for driven tools in Fig. 1 shows; Fig. 3 a longitudinal section of the attachment for driven tools from Fig. 1 shows.

[0025] Fig. Figure 1 shows an example of an attachment for a powered tool. The powered tool can be, for example, a screw driver or a nut driver.

[0026] The attachment part of a driven tool 1 shown as an example is a narrow-space attachment. The attachment part of a driven tool 1 comprises an elongated housing 3. The elongated housing 3 comprises an upper housing part or first housing part 3a and a lower housing part or second housing part 3b. The upper housing part 3a is connected to the lower housing part 3b.

[0027] Fig. Figure 2 shows an exploded view of the attachment of a power tool 1. The attachment of a power tool 1 comprises an input gear, or, more briefly, an input gear 9, and an output gear 11 arranged in the elongated housing 3. The input gear 9 is arranged at a first end of the elongated housing 3. The output gear 9 is arranged at a second end of the housing 3.

[0028] The input gear 9 is drivingly connected to the output gear 11 via a plurality of intermediate gears 13a, 13b. In the example shown, five intermediate gears are provided, comprising a first intermediate gear 13a meshing with the output gear 11, and four second intermediate gears arranged between the input gear 9 and the first intermediate gear 13a to transmit rotation and torque between them. However, the number of intermediate gears can be freely varied to suitably adjust the length of the throat attachment, as long as a first intermediate gear 13 is present. The number of second intermediate gears 13b can thus be any integer starting from zero. In the example shown, all gears are spur gears.

[0029] The output gear 11 includes an output connection or interface 11a. The output interface 11a can be configured, for example, to receive a wrench bit, a screw bit, a nut, or a screw head.

[0030] The first intermediate gear 13a is rotatably mounted on a first intermediate gear shaft 15a by means of needle bearings 16a. Similarly, each second intermediate gear 13b is rotatably mounted on a second intermediate gear shaft 15b by means of a respective needle bearing 16b.

[0031] The first intermediate gear shaft 15a is hollow. In the example shown, it has a cylindrical bore 17a extending axially from one end to the other of the first intermediate gear shaft 15a. However, in other embodiments, the hollow configuration of the first intermediate gear shaft can be achieved by an interior space with any cross-sectional geometry, which may or may not extend over the entire axial length of the first intermediate gear shaft.

[0032] A torque sensor 19 is housed in the bore 17a. In the example shown, the torque sensor is formed from a piezoelectric element that is inserted into the bore and secured there by suitable means, such as adhesive bonding, a press fit, or additional fastening elements. In the example shown, the piezoelectric element has essentially the same cross-sectional geometry as the bore 17a.

[0033] The piezoelectric element is configured to detect radial deformations of the first intermediate gear shaft 15a and generate an electrical signal proportional to the radial deformation. Such radial deformations occur when an input torque is transmitted from the input gear via the second intermediate gears 13b to the first intermediate gear 13a, and when the output gear generates a counter-torque to the first intermediate gear 13a. The deformation of the first intermediate gear shaft 15a, and thus the signal generated by the torque sensor 19, is then proportional to the counter-torque generated by the output gear 11, and the actual torque acting on the output gear can thereby be calculated.

[0034] In another embodiment (not shown), the torque sensor is formed from or comprises a strain gauge accommodated in the interior of the first intermediate gear shaft. The strain gauge may, for example, comprise a thin-film sensor attached to the inner wall of the first intermediate gear shaft or to a pin, needle, or the like inserted into the interior of the first intermediate gear shaft.

[0035] The attachment of a power tool 1 can optionally include an electronics unit 7. The torque sensor 19 is connected to the electronics unit 7 via an electrical cable 7a. The electronics unit 7 can be configured to drive the torque sensor 19. The electronics unit 7 can be configured to receive measured values ​​from the torque sensor 19. The electronics unit 7 can be configured to process measured values ​​from the torque sensor 19. For example, the electronics unit 7 can be configured to process the measurements or detections made by the piezoelectric element and determine the torque corresponding to the restoring deformation of the first intermediate gear shaft 15a.

[0036] The electronics unit 7 may be configured to communicate wirelessly or via wires with a power tool and / or to communicate wirelessly or via wires with a control unit configured to control the operation of the power tool. The electronics unit 7 may be configured to transmit raw measurements and / or the processed measurements. Optionally, the electronics unit 7 may include a display unit 7b configured to display processed measurements from the torque sensor 19. The electronics unit 7 may be arranged on the outer surface of the elongated housing 3, for example, on the upper housing part 3a.

[0037] The torque sensor 19 could otherwise be configured to be electrically connected directly to and powered by the driven tool.

[0038] In the embodiment shown in the figures, the first intermediate gear meshes with the output gear. This can be advantageous because the signal generated by the torque sensor then closely matches the actual torque acting on the output gear. In other embodiments, however, the first intermediate gear can be any of the intermediate gears, so that it meshes with the input gear and / or with one or two of the second intermediate gears. In such other embodiments, the friction created by the meshing of the gears between the first intermediate gear and the output gear must be compensated for when determining the actual torque acting on the output gear.

[0039] The electronics unit 7 may include processing circuitry configured to process measurements from the torque sensor 19. Furthermore, the electronics unit 7 may include a storage medium containing computer code that, when executed by the processing circuitry, causes the electronics unit 7 to determine a torque at the output gear based on the measurements from the torque sensor 5. The processing circuitry may be configured to display the determined torque on a display 7b of the electronics unit 7.

[0040] The processing circuitry may use any combination of one or more suitable central processing units (CPUs), multiprocessors, microcontrollers, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc., capable of performing all of the torque determination operations disclosed herein based on the values ​​measured by the torque sensor 19.

[0041] The storage medium can, for example, be embodied as a memory such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM) or an electrically erasable programmable read-only memory (EEPROM) and, in particular, as a non-volatile storage medium of a device in an external memory such as a USB memory (Universal Serial Bus - USB) or a flash memory such as a compact flash memory.

[0042] The electronics unit 7 may comprise a transmitter configured to wirelessly transmit, for example, measured values ​​received from the torque sensor to a power tool or a power tool control unit.

[0043] Above, the inventive concept has been described using two specific embodiments. However, the inventive concept is not limited to any of these embodiments. It will be apparent to a person skilled in the art that the inventive concept can be modified within its scope, which is defined by the following claims. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3388199

[0005]

Claims

[1] Attachment part of a driven tool (1) for a driven tool, comprising: - an elongated housing (3) with an upper housing part (3a) and a lower housing part (3b) connected to the upper housing part (3a), - an input gear (9) configured to be connectable to an output shaft of a driven tool, the input gear (9) being arranged at a first end of the housing (3), - an output gear (11) having an output interface (11a), wherein the output gear (11) is arranged at a second end of the housing (3), - a first intermediate gear (13a) arranged within the housing (3) and configured to transmit the torque of the input gear (9) to the output gear (11), the first intermediate gear (13a) being rotatably mounted on a first intermediate gear shaft (15a), - at least one torque sensor (19) configured to detect radial forces acting on the first intermediate gear shaft (15a) in order to thereby obtain a measure of the torque at the output gear (11), and - an electronics unit configured to receive measured values ​​from the torque sensor (19) and adapted to transmit the measured values ​​to a control unit of a power tool which controls the operation of the power tool. [2] The attachment of a power tool (1) according to claim 1, wherein the torque sensor (19) is configured to measure the radial deformation of the first gear shaft (15a). [3] Attachment part of a driven tool (1) according to claim 1 or 2, wherein the first intermediate gear (13a) meshes with the output gear (11). [4] Attachment part of a driven tool (1) according to one of claims 1 to 3, wherein the first intermediate gear shaft (15a) is hollow and the torque sensor (19) is accommodated in the first intermediate gear shaft (15a). [5] Attachment part of a driven tool (1) according to one of claims 1 to 4, wherein the torque sensor (19) comprises a piezoelectric element. [6] Attachment part of a driven tool (1) according to one of claims 1 to 5, wherein the torque sensor comprises a strain gauge. [7] A power tool attachment (1) according to any one of claims 1 to 6, further comprising a plurality of second intermediate gears (13b) disposed within the housing (3) and configured to transmit the torque of the input gear (9) to the output gear (11). [8] Attachment part of a driven tool (1) according to one of claims 1 to 7, wherein the input gear (9), the output gear (11) and the intermediate gear(s) (13a, 13b) are spur gears. [9] Attachment part of a driven tool (1) according to one of claims 1 to 8, wherein each intermediate gear (13a, 13b) is arranged on the respective intermediate gear shaft (15a, 15b) by means of needle bearings (16a, 16b). [10] Attachment part of a powered tool (1) according to one of claims 1 to 9, wherein the electronic unit (7) is configured to drive the torque sensor (19). [11] Attachment part of a powered tool (1) according to claim 10, wherein the electronic unit (7) is configured to process the measured values. [12] Attachment part of a driven tool (1) according to one of claims 1 to 11, wherein the attachment part of a driven tool (1) is a narrow space attachment. [13] Attachment part of a power tool (1) according to one of the claims, wherein the output interface (11a) is configured to receive a wrench bit, a screw bit, a nut or a screw head. [14] Attachment part of a powered tool (1) according to one of the claims, wherein the electronics unit (7) comprises a transmitter configured to wirelessly transmit measured values ​​received from the torque sensor (19) to a powered tool (1) or a control unit of a powered tool (1). [15] Attachment part of a powered tool (1) according to one of the claims, wherein the electronic unit (7) comprises a processing circuit configured to process measured values ​​of the torque sensor (19) and has at least one of the following units: central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, application-specific integrated circuit ASIC, field-programmable gate array FPGA. [16] A powered tool comprising a power tool attachment (1) and a control unit controlling the operation of the power tool, comprising: the attachment part of a driven tool (1), comprising - an elongated housing (3) with an upper housing part (3a) and a lower housing part (3b) connected to the upper housing part (3a), - an input gear (9) configured to be connectable to an output shaft of a driven screwing tool, the input gear (9) being arranged at a first end of the housing (3), - an output gear (11) having an output interface (11a), wherein the output gear (11) is arranged at a second end of the housing (3), - a first intermediate gear (13a) arranged within the housing (3) and configured to transmit the torque of the input gear (9) to the output gear (11), the first intermediate gear (13a) being rotatably mounted on a first intermediate gear shaft (15a), - at least one torque sensor (19) configured to detect radial forces acting on the first intermediate gear shaft (15a) in order to thereby obtain a measure of the torque at the output gear (11), and - wherein the attachment part of a powered tool (1) comprises an electronic unit (7) configured to receive measured values ​​from the torque sensor (19); wherein the electronic unit (7) is designed to transmit the measured values ​​to the control unit of the powered tool. [17] A power tool according to claim 16, wherein the electronic unit (7) comprises a processing circuit configured to process the measured values ​​to determine a torque based on the measured values ​​of the radial forces acting on the first intermediate gear shaft. [18] A powered tool according to claim 16 or 17, wherein the electronics unit (7) is configured to transmit unprocessed and / or processed measured values ​​to the control unit. [19] System, comprehensive a driven tool with drive electronics, and an attachment part of a driven tool (1) with - an elongated housing (3) with an upper housing part (3a) and a lower housing part (3b) which is connected to the upper housing part (3a), - an input gear (9) configured to be connectable to an output shaft of a driven tool, the input gear (9) being arranged at a first end of the housing (3), - an output gear (11) having an output interface (11a), wherein the output gear (11) is arranged at a second end of the housing (3), - a first intermediate gear (13a) arranged within the housing (3) and configured to transmit the torque of the input gear (9) to the output gear (11), the first intermediate gear (13a) being rotatably mounted on a first intermediate gear shaft (15a), - at least one torque sensor (19) configured to detect radial forces acting on the first intermediate gear shaft (15a) in order to thereby obtain a measure of the torque at the output gear (11), and - an electronic unit (7) configured to receive measured values ​​from the torque sensor (19); wherein the electronics unit (7) is designed and arranged to be connected to the drive electronics of the driven tool. [20] The system of claim 19, wherein the electronic unit (7) comprises a processing circuit configured to process the measured values ​​to determine the torque based on the measured values ​​of the radial forces acting on the first intermediate gear shaft.

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