EP4375013A1

EP4375013A1 - Socket falling prevention device for impact tool

Info

Publication number: EP4375013A1
Application number: EP22208807.2A
Authority: EP
Inventors: Henrik Walter; Wolfgang Ludwig; Markus Hartmann; Kit Siang Tan; Michael Kögel
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2022-11-22
Filing date: 2022-11-22
Publication date: 2024-05-29
Also published as: WO2024110197A1

Abstract

The present invention provides a socket falling prevention device for an impact tool, the impact tool comprising a housing, with an anvil being provided in a protruding manner in front of the housing, and a socket being removably mounted on the anvil; the socket falling prevention device comprises at least one connecting member, for connecting the socket to a non-rotating portion of the impact tool by axial shape-fitted fixing to prevent the socket from falling off. Using the socket falling prevention device according to the present invention, the socket is fixedly connected directly to the non-rotating portion of the impact tool in the axial direction by means of the connecting member, rather than to the anvil, so the strength of the anvil will not be affected. Furthermore, the axial fixed connection by form fit will not hinder normal operation of the socket and ensures a fixed connection between the socket and impact tool in the axial direction, effectively preventing the socket from falling off the anvil of the impact tool.

Description

TECHNICAL FIELD

The present invention relates to an impact tool, in particular to a socket falling prevention device for an impact tool.

BACKGROUND ART

An impact tool, in particular an impact wrench, generally comprises a motor as a drive source, a gear transmission mechanism and main shaft which rotate as the motor performs a driving action, a hammer, and an anvil as an output shaft. The main shaft and hammer are driven by the motor and can convert rotation of the main shaft to an intermittent rotational striking force (impact) of the hammer to act on the anvil, in order to provide rotation and striking to the anvil, thereby intermittently transmitting a rotational striking driving force to a top end tool, such as a socket connected to the anvil, to perform tightening/removing of screws/bolts/nuts. Herein, the central rotational axis of the anvil is the axial direction, which generally extends in the front-rear direction of the anvil.
Generally, a front end of the anvil forms an interface, such as an outer square, for mounting and connecting a socket. Sockets for impact tools are common and standard components. Sockets are generally cylindrical, and comprise: a rearward part, provided with a hexagonal shape of hole and in which the head of a hexagonal bolt, etc. can be inserted; and a frontward part, joined coaxially to the rearward part, and formed with a square hole in which the anvil head is inserted. A circumferential groove is formed on the frontward part, and a through-hole orthogonal to an axis of the frontward part is formed in a penetrating manner at the position of the groove.
In the state of the art, mounting a socket on the square interface of an anvil is mainly based on two principles: form fit or friction. In the case of form fit, the square interface of the anvil provides a through-hole or a detent pin. In the case of a through-hole, form fit between the anvil and socket is accomplished by a pin passing through the aligned through-holes in the anvil and socket. If a detent pin is used, a spring and the detent pin are integrated in a blind hole in the square interface of the anvil; under the action of the spring, the detent pin can be detained or extrude the through-hole of the socket, thus giving rise to a form-fit. However, both methods will weaken the structure of the square interface of the anvil, and this might shorten the lifetime of the anvil of a high-power impact tool.
In the case of a friction-based connection between the anvil and socket, a friction ring is generally used. This is a radially compressible annular element, which is located in a circumferential groove at a front part of the square interface of the anvil, and thus will not have an adverse effect on the structure of the square interface. However, the frictional force of the friction ring is limited, and decreases with ageing and wear of the compressive annular element. In the case of a heavy socket, the axial fixing force might not be enough to meet safety requirements.
The weight of a socket of an impact wrench for high-requirement applications can exceed 1.2 kg. If the socket inadvertently drops from the anvil of the impact tool, interrupting work, it might damage things or even seriously injure people. Thus, there is a need for a device that prevents a socket from falling off the anvil of an impact tool.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a socket falling prevention device that effectively prevents a socket falling from the anvil of an impact tool.
A socket falling prevention device for an impact tool, the impact tool comprising a housing, with an anvil being provided in a protruding manner in front of the housing, and a socket being removably mounted on the anvil; the socket falling prevention device comprises at least one connecting member, for fixedly connecting the socket by form fit to a non-rotating portion of the impact tool in an axial direction to prevent the socket from falling off.
By the socket falling prevention device according to the present invention, the socket is fixedly connected directly to the non-rotating portion of the impact tool in the axial direction by means of the connecting member, rather than to the anvil, so the strength of the square interface of the anvil will not be affected. Furthermore, the axial fixed connection by form fit will not hinder normal circumferential rotary operation of the socket and ensures that the socket and impact tool are axially fixed relative to each other, so can effectively prevent the socket from falling off the anvil of the impact tool.
According to an embodiment of the present invention, the connecting member comprises a first end fixedly connected to the non-rotating portion in the axial direction and a second end fixedly connected to the socket in the axial direction, the first end being connected to the second end by means of an axially extending connecting part, and the connecting member rotates in synchrony with the socket. Thus, the socket is fixedly connected to the impact tool in the axial direction by means of the connecting member, and the socket is still able to rotate under the driving action of the anvil, with the connecting member rotating in synchrony with the socket.
A front part of the housing of the impact tool is provided with a shaft supporting part for rotatably supporting the anvil, and a bushing is provided inside the shaft supporting part, the bushing protruding from a front end of the shaft supporting part and forming a circumferentially arranged annular channel, the annular channel forming the non-rotating component. By using the annular channel of the bushing protruding from the shaft supporting part as the non-rotating component, a convenient and reliable non-rotating connecting portion is provided for connecting the socket directly to the impact tool, making the axial connection of the socket to the impact tool simple and easy.
The socket is provided with a through-hole substantially perpendicular to the central axis of the socket, the first end comprises a pair of arc-shaped clips which are partially engaged in the annular channel to fixedly connect the connecting member to the non-rotating component in the axial direction, and the second end comprises an protruding piece extending substantially perpendicular to the connecting part, the protruding piece being insertable in the through-hole to fixedly connect the connecting member to the socket in the axial direction. The arc-shaped clips of the first end of the connecting member are engaged in the non-rotating annular channel, the arc-shaped clips being in a clearance fit with the annular channel, i.e. the arc-shaped clips can rotate in the annular channel. Since the protruding piece of the connecting member is inserted in the through-hole in the socket, the connecting member and socket are fixed relative to each other in the axial direction, so the connecting member can rotate in synchrony with the socket.
A peripheral face of the socket is further provided with a circumferential groove, and the second end further comprises a pair of elastic arms which are partially engaged in the groove, mainly for keeping the connecting member in place against centrifugal forces. Thus, when the elastic arms of the second end of the connecting member are engaged in the circumferential groove of the socket, the elastic arms press tightly against the groove on the peripheral face of the socket in a radial direction to a certain extent, such that the socket is fixed relative to the connecting member in the axial direction.
Preferably, a free end of the protruding piece comprises an elastic side bend, which is engaged with the peripheral face of the socket. Friction between the peripheral face of the socket and the elastic side bend ensures the fixed connection between the connecting member and the socket against centrifugal forces; the connecting member and the socket rotate in synchrony in the circumferential direction, while remaining stationary relative to each other in the axial direction.
According to another embodiment of the present invention, the connecting member comprises a first end fixedly connected to the non-rotating portion in the axial direction and a second end fixedly connected to the socket in the axial direction, the first end being connected to the second end by means of an axially extending connecting part, and the socket is circumferentially rotatable relative to the connecting member. Thus, the connecting member fixes the socket to the impact tool in the axial direction, and may or may not rotate in synchrony with the socket, depending on friction conditions between connecting member and non-rotating component respectively connecting member and socket. That is to say, the relative positions of the non-rotating portion, the connecting component and the socket in the axial direction are fixed, and at the same time they can rotate relative to each other; thus, the function of preventing detachment of the socket is realized while ensuring as large a degree of mounting freedom as possible.
A peripheral face of the socket is provided with a circumferential groove, and a fix stopper is provided on a peripheral face of a shaft supporting part of the impact tool, the fix stopper forming the non-rotating portion. A protruding fix stopper is installed as the non-rotating portion on the peripheral face of the shaft supporting part of the impact tool; the shaft supporting part is part of the housing, and is therefore static, not rotating. Installing a fix stopper on the outside of the shaft supporting part is a simple and convenient solution for forming an additional non-rotating portion on the impact wrench.
The first end comprises a long hole disposed at one end of the connecting part, the long hole being fitted over the fix stopper to fixedly connect the connecting member to the non-rotating portion in the axial direction, and the second end comprises a pair of elastic arms which are engageable in the groove, the elastic arms being circumferentially rotatable along the groove. Due to the shape-fit between the long hole and the fix stopper, the connecting member is fixedly connected to the non-rotating portion of the impact tool in the axial direction. The elastic arms of the second end serve the function of fixedly connecting the connecting member to the socket in the axial direction, while rotation is possible between the groove and the elastic arms.
The second end further comprises a push rod, for disengaging the long hole from the fix stopper. When the push rod is pressed down, the connecting part transmits the moment of force to the first end, causing the first end to move upwards; the long hole disengages from the fix stopper, thereby breaking the connection between the connecting member and the impact tool.
According to another embodiment of the present invention, a peripheral face of the socket is provided with a circumferential groove, a pair of connecting holes are provided on a peripheral face of a shaft supporting part of the impact tool, the first end of the connecting member comprises two pins which are respectively engageable in the connecting holes, the second end comprises an arc-shaped ring which is at least partially engaged in the groove, and rotation of the pins in the connecting holes drives the second end to be engaged in the groove or released from the groove. When the arc-shaped ring is engaged in the groove, the socket is fixedly connected to the impact tool in the axial direction; at the same time, the arc-shaped ring can rotate circumferentially in the groove, the connecting member and impact tool are stationary relative to each other, and the socket can rotate relative to the connecting member and the impact tool.
Alternatively, a peripheral face of the socket is provided with a circumferential groove, a fastening part with at least one pair of connecting holes are provided on a peripheral face of a shaft supporting part of the impact tool, the fastening part forming the non-rotating portion, the first end of the connecting member comprises two pins which are respectively insertable in the connecting hole, the second end comprises an arc-shaped ring which is at least partially engaged in the groove, and rotation of the pins in the connecting hole drives the second end to be engaged in the groove or released from the groove. Thus, there is no need to make holes directly in the housing; instead, the pins are connected by forming a connecting hole as a non-rotating portion in a fastening part attached to the front end of the housing, so processing and assembly are simpler.
Preferably, the pair of holes are offset to each other in axial direction to achieve two resting positions of the connecting member.
According to another embodiment of the present invention, the connecting member is a ball-interlock chuck, the steel balls of the chuck engaging into circumferential groove of the socket.
According to another embodiment of the present invention, the first end comprises a pair of arc-shaped clips which are partially engaged in the annular channel, the second end comprises a pair of elastic arms which are engageable in the groove, and the connecting part is an axially extending beam connecting the first end to the second end. The socket can be fixedly connected to the impact tool in the axial direction simply by engaging the arc-shaped clips of the first end and the elastic arms of the second end in the annular channel of the impact tool and the circumferential groove of the socket respectively. Preferably, a reinforced structure or material is chosen for the beam serving as the connecting part, to ensure the reliability of the axial fixed connection.
According to a preferred embodiment of the present invention, the connecting part is formed as a ring-shaped sleeve which is circumferentially openable or closable, the first end and second end are provided at two ends of the ring-shaped sleeve respectively, the first end comprises an annular flange which is at least partially engaged in the annular channel, and the second end comprises a rib which is at least partially engaged in the groove. The fact that the connecting part is a circumferentially openable/closable sleeve greatly increases the strength of the connecting part, to better achieve the effect of fixing the socket to the non-rotating portion of the impact tool in the axial direction.
Preferably, the sleeve is formed by joining together two half-rings each having an engagement structure, the engagement structure being a snap joint or hinge respectively provided on at least one side edge of the two half-rings. The engagement structure is configured to realize the function of opening/closing the sleeve. Such a sleeve can fixedly connect the socket to the impact tool in the axial direction without the need for an additional fastening component.
Alternatively, the sleeve is formed by joining together two half-rings each having an engagement structure, and at least one elastic strap for retaining the sleeve is provided outside the sleeve, the elastic strap being fitted round a peripheral face of the sleeve close to the engagement structure. Thus, the engagement structure here is to keep the two half-rings axially aligned to each other. The elastic strap helps to keep the sleeve in a closed state during operation.
The engagement structure is a recess provided at an end of one half-ring and a protrusion provided at an end of the other half-ring, the two half-rings being locked together to form the sleeve when the protrusion is accommodated in the recess.
Alternatively, the engagement structure is a hook part and a slot part respectively provided at ends of the two half-rings, the hook part being engaged in the slot part, and the two half-rings being locked together to form the sleeve. The engagement structure forms a hinge between the two half rings to realize the function of opening/closing the sleeve. When the sleeve is opened, the socket and the annular channel of the impact tool are respectively engaged with the rib and the flange inside the sleeve, then the engagement structure is closed via the locking mechanism of the engagement structure, such as the recess/protrusion or hook/slot locking mechanism, and in this way the socket is fixedly connected to the impact tool in the axial direction.
Preferably, the engagement structure (30) is positioned near to annular channel of the impact tool. This results in lever conditions that, when trying to pull out the socket, cause closing forces preventing releasing the socket (principle of self-locking). To release the socket the half-rings can be opened by pressing their lateral push rods.
The impact tool is an impact wrench. In view of the fact that general-purpose sockets for impact tools currently on the market are not suitable for other impact tools such as impact drivers, for example, impact drivers often clamp a tool such as a drill bit by means of a tool chuck connected to the anvil head to perform construction work, and there is no risk of the socket falling off the anvil. Thus, the socket falling prevention device of the present invention is especially suitable for impact wrenches.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the embodiments mentioned can be gained from the following detailed description with reference to the drawings. It is emphasized that the various components are not necessarily drawn to scale. In fact, dimensions can be enlarged or reduced at will for the purpose of clear discussion. In the drawings, the same reference numerals refer to the same elements.

Fig. 1 is a schematic drawing of an impact tool and a socket in a schematic embodiment of the present invention.
Fig. 2 is a perspective view of a falling prevention device in a schematic embodiment of the present invention.
Figs. 2a - 2c are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 2.
Fig. 3 is a schematic drawing of a socket falling prevention device for an impact tool according to another embodiment of the present invention.
Figs. 3a - 3c are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 3.
Fig. 4 is a schematic drawing of a socket falling prevention device for an impact tool according to a third embodiment of the present invention.
Figs. 46a - 4d are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 4.
Fig. 5 is a schematic drawing of a socket falling prevention device for an impact tool according to a fourth embodiment of the present invention.
Figs. 5a - 5d are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 5.
Fig. 6 is a schematic drawing of a socket falling prevention device for an impact tool according to a fifth embodiment of the present invention.
Figs. 6a - 6b are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 6.
Fig. 7 is a schematic drawing of a socket falling prevention device for an impact tool according to a sixth embodiment of the present invention.
Figs. 7a - 7c are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 7.
Fig. 8 is a schematic drawing of a socket falling prevention device for an impact tool according to a seventh embodiment of the present invention.
Figs. 8a - 8c are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 8.
Fig. 9 is a schematic drawing of a socket falling prevention device for an impact tool according to an eighth embodiment of the present invention.
Figs. 9a - 9c are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 9.
Fig. 10 is a schematic drawing of a socket falling prevention device for an impact tool according to a ninth embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

A socket falling prevention device for an impact tool is described below with reference to Figs. 1 - 10.
Referring to Figs. 1 and 2, an impact wrench 1 is exemplary shown as an impact tool. The impact wrench of the present invention comprises: a main housing 2 accommodating a motor, the main housing 2 generally being formed by fitting together left and right half-housings; and a gearbox housing 3 made of metal, the gearbox housing 3 being fitted in front of the main housing 2 (the left side in Fig. 1). As a front-side housing, the gearbox housing accommodates a gear transmission mechanism, a main shaft, a striking mechanism, and an anvil 4 serving as an output shaft. The gear transmission mechanism and striking mechanism are well-known in industry. The gear transmission mechanism converts high-speed rotation of a motor shaft to rotation of the main shaft by speed reduction, torque is transmitted to the striking mechanism, and a hammer repeatedly engages with and disengages from the anvil 4, thereby producing impacts in the direction of rotation.
The gearbox housing 3 is a tubular body, a rear part thereof being inserted in the main housing 2. A front part of the gearbox housing 3 that is exposed outside the main housing 2 has a tapered form that is narrower at the front, and is covered by a shroud made of synthetic resin. The anvil 4 is shaft-supported by a shaft supporting part 5 formed at the front end of the gearbox housing 3, and protrudes towards the front. A socket 6 is removably mounted on a front end of the anvil 4 that protrudes from the shaft supporting part 5. A bushing 7 for rotatably supporting the anvil is further provided inside the shaft supporting part 5 at the front end of the gearbox housing.
In the present invention, the socket used for the impact wrench is a general-purpose, standard component. The socket 6 removably mounted on the head of the anvil 4 is cylindrical, and comprises: a rearward part 61, provided with a hexagonal hole 62 in which the head of a hexagonal bolt, etc. can be inserted; and a frontward part 63, joined coaxially to the rearward part 61, and formed with a square hole in which the anvil head is inserted. A circumferential groove 65 is formed on the frontward part 63, and a through-hole 66 orthogonal to the axis of the frontward part 63 is formed in a penetrating manner at the position of the groove 65.
The present invention provides a socket falling prevention device 8, to fixedly connect the socket 6 directly to the impact tool, in particular the impact wrench 1, in the axial direction. The impact wrench 1 comprises a non-rotating portion 10, and the socket falling prevention device 8 comprises a connecting member that is fixedly connected to the non-rotating portion 10 and the socket 6 respectively in the axial direction, while not affecting movement of the socket in the rotation direction driven by the anvil head. That is to say, the socket falling prevention device 8 is not only able to rotate in synchrony with the socket, but also able to remain stationary relative to the non-rotating portion 10, and can also rotate relative to the socket and/or the non-rotating portion 10, as long as the socket falling prevention device 8 is fixedly connected to the non-rotating portion 10 and the socket 6 in the axial direction, wherein the fixed connection is achieved by form fit; thus, the socket is fixed to the impact tool in the axial direction in a simple and reliable manner, and the socket 6 will not detach from the anvil 4 inadvertently.
The socket falling prevention device of the present invention is especially suitable for impact tools with high application requirements, in particular impact wrenches. Such application scenarios often require sockets of heavy weight, while the torque load transmitted by the anvil is very high, so the strength of the square interface part of the anvil needs to be guaranteed. Thus, the socket falling prevention device of the present invention is especially suitable for impact wrenches with high torque requirements due to the fact that it fixedly connects the socket directly to the non-rotating portion of the impact wrench, not to the anvil, in the axial direction.
Figs. 2 and 2a - 2c illustrate a socket falling prevention device according to an embodiment of the present invention. As shown in Fig. 2, the bushing 7 for rotatably supporting the anvil is provided inside the shaft supporting part 5 at the front end of the gearbox housing 3 of the impact wrench 1. In this embodiment, the bushing 7 for shaft-supporting the anvil 4 protrudes from the front end of the housing and forms a circumferentially annular channel 11. The bushing 7 is generally integrally formed with the shaft supporting part 5, and is at least engaged with the inside of the shaft supporting part 5. Both the bushing 7 and the shaft supporting part 5 may be regarded as part of the gearbox housing 3. Thus, the shaft supporting part 5 and the bushing 7 are both relatively stationary components, i.e. when the impact wrench 1 is working, neither the shaft supporting part 5 nor the bushing 7 rotates, but the anvil 4 serving as the output shaft rotates about a central axis in a hole formed by the shaft supporting part 5 and the bushing 7.
The socket falling prevention device 8 of the present invention is a connecting member 20; the connecting member 20 comprises a first end 21 connected to the annular channel 11 and a second end 22 connected to the socket 6, the first end 21 being connected to the second end 22 by an axially extending connecting part 23. The first end 21 comprises a pair of arc-shaped clips which are at least partially engaged in the annular channel 11; here, the annular channel 11 serves as the non-rotating portion of the present invention. The arc-shaped clips are in a clearance fit with the annular channel 11; the arc-shaped clips can rotate in the annular channel 11, while the annular channel 11 limits axial movement of the arc-shaped clips. The second end 22 comprises a protruding piece 24 extending substantially perpendicular to the connecting part. The protruding piece 24 can be inserted in the through-hole 66, and the elasticity of the protruding piece 24 enables the protruding piece 24 to be supported firmly in the through-hole 66, so the connecting member and socket are fixed relative to each other in the axial direction. Thus, the first end 21 fixes the connecting member 20 to the non-rotating portion 10 in the axial direction, the second end 22 fixes the connecting member 20 to the socket 6 in the axial direction, and the axially extending connecting part 13 ensures that the positions of the first end and second end do not change in the axial direction. Thus, the connecting member fixedly connects the socket 6 to the impact wrench 1 in the axial direction, and the socket 6 will not move axially relative to the non-rotating portion.
Preferably, the protruding piece 24forms a spring-elastic "press-fit" towards the through-hole 66 to secure the connecting member 20 from falling off due to centrifugal force. For example, the protruding piece 24 further comprises an elastic side bend, which could be in a way that it is a little bit bigger than the through hole and generates a friction / clamping force. This could secure the protruding piece 24 against falling off due to centrifugal force.
According to a preferred solution of the present invention, the second end 22 further comprises a pair of elastic arms 25 which are partially engaged in the groove, for the purpose of axially retaining the socket. The protruding piece 24 is located on the centre line of the second end, and the elastic arms 25 extend in an arc shape to two sides from the centre of the second end, the curvature of the elastic arms 25 being substantially the same as or slightly less than the curvature of the groove 65 of the socket. Thus, when the elastic arms 25 are engaged in the circumferential groove 65 of the socket, the elastic arms 25 press tightly against the groove on the peripheral face of the socket in a radial direction to a certain extent, thereby securing the connecting member from falling off due to centrifugal force. Thus, the socket 6 is fixed relative to the connecting member in the axial direction.
In this embodiment, the arc-shaped clips of the first end 21 of the connecting member are rotatable along the non-rotating annular channel 11, and the protruding piece 24 of the second end 22 of the connecting member is inserted in the through-hole 66 in the socket, such that a fixed connection is formed between the connecting member and the socket, enabling the connecting member 20 to rotate in synchrony with the socket 6.
Figs. 2a - 2b are schematic drawings showing the process of mounting the socket falling prevention device shown in Fig. 2. Firstly, as shown in Fig. 2a, the socket 6 is mounted on the head of the anvil 4; the through-hole 66 of the socket is aligned with a through-hole of the head of the anvil 4, then the two arc-shaped clips of the first end of the connecting member are engaged in the arc-shaped channel, and the protruding piece 24 of the second end is inserted in the through-hole 66, while the elastic arms 25 are engaged in the groove 65 of the socket. In this way, the connecting member fixedly connects the socket in the axial direction simply and conveniently.
Figs. 3 and 3a - 3c illustrate a socket falling prevention device 10 according to another embodiment of the present invention. Here, the impact wrench and the socket are the same as in the embodiment shown in Fig. 2, but the non-rotating portion 10 of the impact tool is different. In the embodiment shown in Fig. 2, the bushing 7 protrudes from the front end of the shaft supporting part 5 and forms an annular channel 11, the annular channel 11 serving as the non-rotating portion. In the embodiment shown in Fig. 3, the bushing 7 does not need to protrude from the shaft supporting part 5 and does not need to form the annular channel 11. It will be understood that in this embodiment, the bushing 7 may also have the same structure as in the previous embodiment, except that the bushing 7 no longer serves as the non-rotating portion for connection to the socket falling prevention device. In this embodiment, a fix stopper 12 is provided on a peripheral surface of the shaft supporting part 5, the fix stopper 12 serving as the non-rotating portion 10 for connection to the socket falling prevention device of this embodiment. Installing a protruding fix stopper as a non-rotating portion at the front end of an impact wrench housing is a simple and convenient solution for forming an additional non-rotating portion on an impact wrench.
The socket 6 in this embodiment may have the structure of a standard socket as shown in the previous embodiment; a circumferential groove 65 is formed on the frontward part 63 of the socket 6, and a through-hole 66 orthogonal to the axis of the frontward part 63 is formed in a penetrating manner at the position of the groove 65. It is also possible for no through-hole 66 to be provided, i.e. only a circumferential groove 65 is formed on the frontward part, because the connecting member in this embodiment does not need to be connected to a through-hole, instead being only connected to the circumferential groove 65.
In this embodiment, the first end 21 of the connecting member 20 is a long hole 26 disposed at the front of the connecting part 23, the long hole 26 being fitted over the fix stopper 12 to fix the connecting member axially, and the second end 22 comprises a pair of elastic arms 25 which are engageable in the groove 65, the elastic arms 25 being able to rotate circumferentially along the groove 65. Due to the shape-fit between the long hole and the fix stopper, the connecting member is fixedly connected to the non-rotating portion of the impact tool in the axial direction. The elastic arms 25 of the second end serve the function of fixedly connecting the connecting member 20 to the socket 6 in the axial direction, while rotation is possible between the groove 65 and the elastic arms 25.
Preferably, as shown in Figs. 3b and 3c, the second end further comprises a push rod 27, for disengaging the long hole from the fix stopper. The push rod 27 is a lever, disposed at one side of the connecting part 23 close to the second end and extending upwards to form a pressing part. When the push rod 27 is pressed down, the connecting part transmits the moment of force to the first end 21, causing the first end 21 to move upwards; the long hole 26 disengages from the fix stopper 12 , thereby breaking the connection between the connecting member 20 and the impact tool, and the socket 6 can then be taken off the anvil.
Figs. 4 and 4a - 4c illustrate a socket falling prevention device 10 according to another embodiment of the present invention. Here, the impact tool is the same as in the embodiment shown in Fig. 2, i.e. the bushing 7 for shaft-supporting the anvil 4 protrudes from the front end of the housing and forms a circumferentially arranged annular channel 11, and the socket 6 is the same as in the embodiment shown in Fig. 3, i.e. a circumferential groove 65 is formed on the frontward part 63 of the socket 6, and a through-hole 66 orthogonal to the axis of the frontward part 63 is formed in a penetrating manner at the position of the groove 65, but it is also possible for no through-hole 66 to be provided.
In this embodiment, the connecting member 20 is a sleeve that can be opened/closed in the circumferential direction, i.e. the connecting part 23 has a shape of a sleeve overall. The first end 21 and second end 22 are respectively two end faces of the sleeve, and the sleeve is continuous in both the axial and circumferential directions. Thus, the strength of the connecting part 23 is greatly increased, to better achieve the effect of fixing the socket to the non-rotating portion of the impact tool in the axial direction. Herein, plastic is the preferred material to form the sleeve, but other materials such as sheet metal with integrated hinge could also the thinkable.
The first end 21 comprises an annular flange 28 which is at least partially engaged in the annular channel 11. As shown in Fig. 6a, the annular flange 28 has a structure and dimensions matched to the annular channel 11. Once the annular flange 28 has been engaged in the annular channel 11, the first end 21 of the connecting member is fixed in the axial direction with respect to the annular channel serving as the non-rotating portion, i.e. the annular flange 28 cannot move in the annular channel 11 in the axial direction, but the annular flange 28 can rotate relative to the annular channel 11 in the circumferential direction.
The second end 22 comprises a rib 29 which is at least partially engaged in the groove 65. The rib 29 is a rib which is disposed inside the sleeve and protrudes radially inwards, and is configured to be engaged in the circumferential groove 65 of the socket. The rib 29 may be continuous, or may be two, three, four or more discrete ribs distributed evenly in the circumferential direction around the inside of the second end of the sleeve, such that the rib presses against the bottom of the groove evenly in the circumferential direction; the rib 29 cannot move axially in the groove, and thus achieves axial fixing of the connecting member 20 and socket 6. However, the rib 29 does not restrict relative circumferential movement between the connecting member and the socket. The socket 6 rotates under the driving action of the anvil, while the sleeve may or may not rotate in synchrony with the socket, and may even remain stationary and not rotate with the socket, depending on the manner of fit between the rib and the groove.
Preferably, the sleeve is formed by joining together two half-rings each having an engagement structure 30, the engagement structure being a snap joint or hinge respectively provided on at least one side edge of the two half-rings. The engagement structure 30 is configured to realize the function of opening/closing the sleeve. Such a sleeve can fixedly connect the socket to the impact tool in the axial direction without the need for an additional fastening component. In this embodiment, the engagement structure 30 is a hook and a hole respectively provided in central positions on side edges of the two half-rings; side edges at the other side of the two half-rings may be hinge-connected, then the hook on one half-ring is engaged in the hole on the other half-ring, such that the two half-rings are locked together to form a single sleeve surrounding the non-rotating annular channel of the impact tool and the circumferential groove of the socket. Thus, as shown in Fig. 4b, when the socket 6 is connected to the anvil 4, the connecting member 20 in the form of the sleeve fixedly connects the socket 6 to the impact wrench 1 in the axial direction, and the socket 6 will not fall off the anvil 4 under the action of the connecting member 20.
Figs. 5 and 5a - 5b illustrate a socket falling prevention device for an impact tool according to a fourth embodiment of the present invention. In this embodiment, the structures of the impact tool and the socket are both essentially the same as in the embodiment shown in Fig. 4, and the structure of the connecting member 20 is similar to that in the embodiment shown in Fig. 4, the difference being that the engagement structure 30 is disposed at the first end 21 of the connecting member. This results in lever conditions that, when trying to pull out the socket, cause closing forces preventing releasing the socket (principle of self-locking). To release the socket the half-rings can be opened by pressing their lateral push rods (27), which are also provided on the ring shape sleeve. For example, referring to Figs. 5a and 5b, the engagement structure is a recess provided at first end of one half-ring and a protrusion provided at first end of the other half-ring; when the protrusion is accommodated in the recess, the two half-rings are locked together to form a sleeve. A pair of lateral push rods 27 are provided on the first end of the two half rings of the sleeve. The lateral push rods 27 are preferably provided in the central of the half ring. Thus, the engagement structure 20 could be disengaged by pressing the lateral push rods 27 easily.
Preferably, at least one elastic strap 31 is provided outside the sleeve, to retain the sleeve. Having the engagement structure 30 provided at the first end helps to facilitate insertion into the socket in the mounting process, such that the rib 29 can easily be engaged in the circumferential groove 65. As shown in Fig. 5a, firstly, the annular flange of the first end of the connecting member is engaged in the annular channel of the bushing 7, then as shown in Fig. 5b, the engagement structure 30 is joined together and the elastic strap 31 is fitted over. In this embodiment, the elastic strap 31 is fitted round a peripheral face of the sleeve close to the engagement structure, to help keep the sleeve in a closed state during operation. Preferably, an accommodating channel is formed on the peripheral face to receive the elastic strap 31. Ideally, the socket 6 is inserted into the sleeve, such that the rib 29 inside the sleeve is engaged in the circumferential groove of the socket, thereby fixedly connecting the socket 6 to the non-rotating portion of the impact tool securely in the axial direction.
Figs. 6 and 6a - 6b illustrate a socket falling prevention device for an impact tool according to a fifth embodiment of the present invention. This embodiment differs from the embodiment shown in Fig. 5 in that the engagement structure 30 in this embodiment is disposed at the second end 22 of the connecting member 20. For example, as shown in Fig. 6a, the engagement structure is a hook part and a slot part respectively provided at ends of the two half-rings, the hook part being engaged in the slot part, and the two half-rings being locked together to form a sleeve. Similarly, at least one elastic strip 31 is provided outside the sleeve to retain the sleeve; preferably, the elastic strip 31 is close to the engagement structure, to keep the sleeve in the closed state more effectively. Referring to Fig. 6b, an advantage of having the engagement structure provided at the second end is that the socket can be inserted into the sleeve before closing the sleeve, and once the rib has been engaged in the groove, the hook part and slot part of the two half-rings are joined together, and the elastic strip is moved close to the engagement structure. Thus, the mounting process of fixedly connecting the impact tool to the socket in the axial direction by means of the connecting member is relatively simple and convenient, and the strength of the axial fixed connection achieved by the connecting member is relatively high.
Figs. 7 and 7a - 7b illustrate a socket falling prevention device for an impact tool according to a sixth embodiment of the present invention. In this embodiment, both the impact tool and the socket are the same as in the embodiment shown in Fig. 4, but a structurally simpler connecting member 20 is provided in this embodiment. Referring to Fig. 7, the first end 21 of the connecting member in this embodiment comprises a pair of arc-shaped clips which are partially engaged in the annular channel, the second end 22 comprises a pair of elastic arms which are engageable in the groove, the elastic arms being able to rotate circumferentially along the groove, and the connecting part is an axially extending beam connecting the first end to the second end. As shown in Figs. 7a and 7b, the socket can be fixedly connected to the impact tool in the axial direction simply by engaging the arc-shaped clips of the first end and the elastic arms of the second end in the annular channel of the impact tool and the circumferential groove of the socket respectively. Preferably, a reinforced structure or material is chosen for the beam serving as the connecting part, to ensure the reliability of the axial fixed connection.
Refer to Figs. 8 and 8a - 8c, which illustrate a socket falling prevention device for an impact tool according to a seventh embodiment of the present invention. In this embodiment, the bushing 7 of the impact tool does not need to protrude from the front end of the shaft supporting part 5, and the front end of the bushing 7 does not need to form an annular channel. In this embodiment, the non-rotating portion is no longer the annular channel in the previous embodiment, instead being the shaft supporting part 5. Preferably, a pair of connecting holes 13 is provided on a peripheral face of the shaft supporting part 5. The first end of the connecting member comprises two pins 32 which can respectively be inserted in the connecting holes, and the second end 22 comprises an arc-shaped ring 33 which is at least partially engaged in the groove; the pins 32 rotate in the connecting holes 13, enabling the arc-shaped ring 33 to be released from the groove 65. When the arc-shaped ring is engaged in the groove, the socket is fixedly connected to the impact tool in the axial direction; at the same time, relative circumferential rotation is possible between the arc-shaped ring and the groove, the connecting member and impact tool are stationary relative to each other, and the socket can rotate relative to the connecting member and the impact tool.Figs. 9 and 9a - 9c illustrate another method of connecting the impact tool to the socket falling prevention device shown in Fig. 8. Unlike the embodiment shown in Fig. 8, in which a pair of connecting holes is formed directly on the peripheral face of the shaft supporting part, the shaft supporting part of the impact tool is provided with a fastening part 14 with a connecting hole 13, the fastening part forming the non-rotating portion. The first end of the connecting member comprises two pins which can be respectively inserted in the connecting hole, the second end comprises an arc-shaped ring which is at least partially engaged in the groove, and the pins rotate in the connecting hole, enabling the second end to be released from the groove. Thus, there is no need to make holes directly in the housing; instead, the pins are connected by forming a connecting hole as a non-rotating portion in a fastening part attached to the front end of the housing, so processing and assembly are simpler.
Preferably, the pair of connecting holes 13 described above are not in line to each other but situated with a slight axial offset to each other in a way that the spring elastic connecting member 20 is elastically deformed and preloaded so it has two resting positions: Engaged and not engaged with the circumferential groove 11 of the socket 6.
Referring to Fig. 10, the socket falling prevention device may be a tool chuck. Typically, the tool chuck is a ball interlock chuck. Such ball interlock chucks are already widely used on impact drivers to secure screw bits. An ordinary ball interlock chuck pushes interlock balls into a circumferential groove of a socket or tool by means of a spring, in order to lock the chuck. The tool chuck in this embodiment has a similar structure, the difference being that the tool chuck of the present invention combining the ball-interlock (as e.g. in a screw bit chuck of an impact driver) with an outside square anvil of an impact wrench to secure sockets from falling off.
Finally, it must be explained that the socket falling prevention device of the present invention fixedly connects the socket directly to the impact tool in the axial direction, so there is no need for an axial fixed connection between the socket and the anvil, and the socket will not detach from the anvil. At the same time, the socket falling prevention device of the present invention does not rule out a conventional fit between the socket and the anvil. Thus, the socket can still be connected to the anvil by means of a friction ring or fix stopper, in which case the socket falling prevention device of the present invention can further ensure that the socket will not detach from the anvil.
As mentioned above, although exemplary embodiments of the present invention have been explained herein with reference to the drawings, the present invention is not limited to the specific embodiments above, and may have many other embodiments. The scope of the present invention should be defined by the claims and their equivalent meanings.

Claims

Socket falling prevention device (8) for an impact tool, the impact tool comprising a housing (2), with an anvil (4) being provided in a protruding manner in front of the housing, and a socket (6) being removably mounted on the anvil (4),
characterized in that
the socket falling prevention device (8) comprises at least one connecting member (20), for fixedly connecting the socket (6) by form fit to a non-rotating portion of the impact tool in an axial direction to prevent the socket (6) from falling off.
Socket falling prevention device (8) for an impact tool according to Claim 1, characterized in that
the connecting member (20) comprises a first end (21) fixedly connected to the non-rotating portion in the axial direction and a second end (22) fixedly connected to the socket (6) in the axial direction, the first end (21) being connected to the second end (22) by means of an axially extending connecting part (23), and the connecting member (20) rotates in synchrony with the socket (6).
Socket falling prevention device (8) for an impact tool according to Claim 2,
characterized in that
a front part of the housing of the impact tool is provided with a shaft supporting part (5) for rotatably supporting the anvil, and a bushing (7) is provided inside the shaft supporting part (5), the bushing (7) protruding from a front end of the shaft supporting part (5) and forming a circumferentially arranged annular channel (11), the annular channel (11) forming the non-rotating portion.
Socket falling prevention device (8) for an impact tool according to Claim 3,
characterized in that
the socket (6) is provided with a through-hole (66) substantially perpendicular to the central axis of the socket (6), the first end (21) comprises a pair of arc-shaped clips which are partially engaged in the annular channel (11) to fixedly connect the connecting member (20) to the non-rotating portion in the axial direction, and the second end (22) comprises an protruding piece (24) extending substantially perpendicular to the connecting part (23), the protruding piece (24) being insertable in the through-hole (66) to fixedly connect the connecting member (20)to the socket (6) in the axial direction.
Socket falling prevention device (8) for an impact tool according to Claim 4,
characterized in that
a peripheral face of the socket (6) is further provided with a circumferential groove (65), and the second end of the connecting member (20) further comprises a pair of elastic arms (25) which are partially engaged in the groove (65), for retaining the socket (6) in the axial direction.
Socket falling prevention device (8) for an impact tool according to Claim 4,
characterized in that
the protruding piece (24) forms a spring-elastic press-fit towards the through-hole (66) to secure the connecting member (20) from falling off due to centrifugal force.
Socket falling prevention device (8) for an impact tool according to Claim 1,
characterized in that
the connecting member (20) comprises a first end (21) fixedly connected to the non-rotating portion in the axial direction and a second end (22) fixedly connected to the socket (6) in the axial direction, the first end (21) being connected to the second end (22) by means of an axially extending connecting part (23), and the socket (6) is circumferentially rotatable relative to the connecting member (20).
Socket falling prevention device (8) for an impact tool according to Claim 7,
characterized in that
a peripheral face of the socket (6) is provided with a circumferential groove (65), and a fix stopper (12) is provided on a peripheral face of a shaft supporting part (5) of the impact tool, the fix stopper (12) forming the non-rotating portion.
Socket falling prevention device (8) for an impact tool according to Claim 8,
characterized in that
the first end (21) comprises a long hole (26) disposed at one end of the connecting part (23), the long hole (26) being fitted over the fix stopper (12) to fixedly connect the connecting member (20) to the non-rotating portion in the axial direction, and the second end (22) comprises a pair of elastic arms (25) which are engageable in the groove (65), the elastic arms (25) being circumferentially rotatable along the groove (65).
Socket falling prevention device (8) for an impact tool according to Claim 9,
characterized in that
the second end (22) further comprises a push rod (27), for disengaging the long hole (26) from the fix stopper (12).
Socket falling prevention device (8) for an impact tool according to Claim 7,
characterized in that
a peripheral face of the socket (6) is provided with a circumferential groove (65), at least one pair of connecting holes (13) are provided on a peripheral face of a shaft supporting part (5) of the impact tool, the first end (21) of the connecting member (20) comprises two pins (32) which are respectively engageable in the connecting holes (13), the second end (22) comprises an arc-shaped ring (33) which is at least partially engaged in the groove (65), and rotation of the pins (32) in the connecting holes drives the second end (22) to be engaged in the groove (65) or released from the groove (65).
Socket falling prevention device (8) for an impact tool according to Claim 7,
characterized in that
a peripheral face of the socket (6) is provided with a circumferential groove (65), a fastening part (14) with at least one pair of connecting holes (13) are provided on a peripheral face of a shaft supporting part of the impact tool, the fastening part (14) forming the non-rotating portion, the first end (21) of the connecting member (20) comprises two pins (32) which are respectively insertable in the connecting hole (13), the second end (22) comprises an arc-shaped ring (33) which is at least partially engaged in the groove (65), and rotation of the pins (32) in the connecting hole (13) drives the second end (22) to be engaged in the groove (65) or released from the groove (65).
Socket falling prevention device (8) for an impact tool according to Claim 11 or 12, characterized in that
the pair of holes are axially offset to each other.
Socket falling prevention device (8) for an impact tool according to Claim 7,
characterized in that
a peripheral face of the socket (6) is provided with a circumferential groove (65), a front part of the housing of the impact tool is provided with a shaft supporting part (5) for rotatably supporting the anvil (4), and a bushing (7) is provided inside the shaft supporting part (5), the bushing (7) protruding from a front end of the housing and forming a circumferentially arranged annular channel (11), the annular channel (11) forming the non-rotating portion.
Socket falling prevention device (8) for an impact tool according to Claim 14,
characterized in that
the connecting member (20) is a ball interlock chuck, wherein the balls of the chuck engaged into the circumferential groove (65) of the socket (6).
Socket falling prevention device (8) for an impact tool according to Claim 14,
characterized in that
the first end (21) comprises a pair of arc-shaped clips which are partially engaged in the annular channel (11), the second end (22) comprises a pair of elastic arms (25) which are engageable in the groove (65), and the connecting part (23) is an axially extending beam connecting the first end (21) to the second end (22).
Socket falling prevention device (8) for an impact tool according to Claim 14,
characterized in that
the connecting part (23) is formed as a ring shaped sleeve which is circumferentially openable or closable, the first end (21) and second end (22) are provided at two ends of the sleeve respectively, the first end (21) comprises an annular flange (28) which is at least partially engaged in the annular channel (11), and the second end (22) comprises a rib (29) which is at least partially engaged in the groove (65).
Socket falling prevention device (8) for an impact tool according to Claim 16,
characterized in that
the sleeve is formed by joining together two half-rings each having an engagement structure (30), the engagement structure (30) being a snap joint or hinge respectively provided on at least one side edge of the two half-rings.
Socket falling prevention device (8) for an impact tool according to Claim 16,
characterized in that
the sleeve is formed by joining together two half-rings each having an engagement structure (30), and a peripheral face of the sleeve is provided with at least one elastic strap (31) for retaining the sleeve, the elastic strap (31) being fitted round the peripheral face of the sleeve close to the engagement structure (30).
Socket falling prevention device (8) for an impact tool according to Claim 18,
characterized in that
the engagement structure (30) is a recess provided at an end of one half-ring and a protrusion provided at an end of the other half-ring, the two half-rings being locked together to form the sleeve when the protrusion is accommodated in the recess.
Socket falling prevention device (8) for an impact tool according to Claim 18,
characterized in that
the engagement structure (30) is a hook part and a slot part respectively provided at ends of the two half-rings, the hook part being engaged in the slot part, and the two half-rings being locked together to form the sleeve.
Socket falling prevention device (8) for an impact tool according to any one of Claims 18-21,
characterized in that
the engagement structure (30) is positioned near to annular channel (11) of the impact tool. This results in lever conditions that, when trying to pull out the socket, cause closing forces preventing releasing the socket (principle of self-locking). To release the socket the half-rings can be opened by pressing their lateral push rods (27).
Socket falling prevention device (8) for an impact tool according to any one of Claims 1 - 20, characterized in that
the impact tool is an impact wrench.