Drilling tool fishing device and drilling machine
By designing the drilling tool salvage device, including the fixing mechanism and traction parts, the problem of the drill tool falling due to the breakage of the power head of the raise drilling rig was solved, and the safe traction and stable salvage of the drilling tool were achieved.
Patent Information
- Application Number
- CN202420101105.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-15
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-01-15
AI Technical Summary
The reverse well drilling rig may cause the power head to break during drilling, causing the drilling tool to fall and cause accidents.
A drilling tool fishing device is designed, including a fixing mechanism and a traction piece. The fixing mechanism is sleeved on the outer periphery of the power head of the drilling rig and is fixedly connected to the power head; one end of the traction component is connected to the fixing mechanism, and the other end is connected to the spindle shell of the drilling rig for pulling the fallen power head.
It effectively avoids the dropping and loss of drilling tools and ensures the safety and stability of the drilling process.
Smart Images

Figure CN222376438U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of drilling equipment, in particular to a drilling tool salvaging device and a drilling rig. Background Art
[0002] Raise boring rig drilling method is a shaft construction method used in mines, hydropower, transportation tunnels and other underground projects. The power head of the raise boring rig uses a hydraulic motor as a power source to drive the power head to rotate. The power head is connected to the drill bit drive to transmit the torque and push-pull force required for rock breaking to the drill bit. During the drilling process, the power head may break, causing the drill bit to fall and cause an accident. Therefore, there is a need for a drill bit salvage device that can lift and fix the drill bit in inclined shaft raise boring construction and avoid the loss of the drill bit. Utility Model Content
[0003] The utility model provides a drilling tool salvaging device and drilling equipment to solve the problem of accidents caused by the falling of drilling tools in the prior art.
[0004] In order to solve the above problems, according to one aspect of the utility model, the utility model provides a drilling tool salvage device, including a fixing mechanism and a traction member, the fixing mechanism is sleeved on the outer periphery of the power head of the drilling rig, and the fixing mechanism is fixedly connected to the power head; one end of the traction member is connected to the fixing mechanism, and the other end of the traction member is connected to the main shaft housing of the drilling rig, and the traction member is used to pull the power head. With this solution, the fixing mechanism is sleeved on the outer periphery of the power head, one end of the traction member is fixedly connected to the fixing mechanism, and the other end is connected to the main shaft housing of the drilling rig, so that the detached power head is pulled by the traction member, and the drilling tool is fixedly connected to the power head and hung on the main shaft housing of the drilling rig with the traction member, so as not to fall off and be lost.
[0005] Furthermore, the fixing mechanism includes a first buckle plate and a second buckle plate, and the first buckle plate and the second buckle plate are connected to form a ring structure. In this way, the first buckle plate and the second buckle plate cooperate with each other and are fixedly connected to form a ring, which is sleeved on the outer periphery of the power head and fixedly connected to the power head.
[0006] Furthermore, a first connection hole is provided on the end surface of the first gusset plate close to the second gusset plate, a second connection hole is provided on the end surface of the second gusset plate close to the first gusset plate, and the first gusset plate and the second gusset plate are fixedly connected through the first connection hole and the second connection hole. In this way, the first connection hole is provided on the end surface of the first gusset plate close to the second gusset plate, and the second connection hole is provided on the end surface of the second gusset plate close to the first gusset plate, so that the first connection hole and the second connection hole are matched and installed, and the first gusset plate and the second gusset plate are fixedly connected together.
[0007] Furthermore, the thickness of the first gusset plate and the second gusset plate are both greater than or equal to 80 mm. Such a configuration makes the thickness of the first gusset plate and the second gusset plate large enough so that the strength of the first gusset plate and the second gusset plate can bear the weight of the drilling tool, thereby preventing the first gusset plate or the second gusset plate from breaking during the process of pulling the drilling tool.
[0008] Further, the first gusset plate is a U-shaped plate, and the inner circle of the U-shaped plate matches the outer circumference of the power head. In this way, the inner circle of the U-shaped plate and the outer circumference of the power head are matched and installed, and the first gusset plate can be fixed on the outer circumference of the power head.
[0009] Furthermore, the U-shaped plate includes two connecting arms and a middle plate, one end of the connecting arm facing away from the second buckle plate is connected to the middle plate, and a first connecting hole is provided on the end surface of the two connecting arms close to the second buckle plate, and the first connecting hole is used to connect the U-shaped plate to the second buckle plate, and the two connecting arms are axially provided with reserved holes, and the traction member is inserted into the reserved holes. In this way, the U-shaped plate includes two connecting arms and a middle plate, and one end of the connecting arm facing away from the second buckle plate is connected to the middle plate, and the outer ring of the U-shaped plate can be chamfered, so that the use of the U-shaped plate is safer and will not cause harm to the installer. The two connecting arms are axially provided with reserved holes, and the traction member is inserted into the reserved holes, and the traction member is fixed in the reserved holes to achieve the connection between the traction member and the fixing mechanism.
[0010] Furthermore, the traction member is a steel wire rope, the middle part of which is fixed to the main shaft housing of the drilling rig, and the two ends of the steel wire rope are respectively fixedly connected to the reserved holes of the two connecting arms, and the diameter of the steel wire rope is greater than 50 mm. In this way, the traction member is a steel wire rope, and the strength and toughness of the steel wire rope are strong, so that the steel wire rope is not easy to break during the traction process. In addition, the cost of using the steel wire rope is low and the service life is long. The diameter of the steel wire rope is greater than 50 mm, which ensures the strength and toughness of the steel wire rope, so that the steel wire rope is not easy to break during the process of traction of the drilling tool, and ensures the safety of use.
[0011] Furthermore, the drilling tool salvage device also includes a fastener, which fixes the first gusset plate and the second gusset plate. In this way, the fastener passes through the first connection hole and the second connection hole to fix the first gusset plate and the second gusset plate together, so that the connection strength is relatively large and it is not easy to loosen. In a specific embodiment of the utility model, the first gusset plate and the second gusset plate can be welded to make the connection more firm and not easy to be damaged.
[0012] Furthermore, the drilling tool salvage device also includes a plug plate structure, which is arranged on the drilling tool and is used to guide and fix the drilling tool so that the drilling tool moves forward in the drilling direction.
[0013] Furthermore, the plug plate structure includes a plug plate member, a connecting plate and two supporting members. The plug plate member is U-shaped, and the plug plate member is clamped in the clamping groove of the drilling tool. The supporting members are supported at the connection between the plug plate member and the drilling tool. The supporting members are arranged on both sides of the drilling tool. The connecting plate connects the two supporting members, and the connecting plate is arranged through the drilling tool.
[0014] According to another aspect of the utility model, a drilling rig is provided, comprising a motor, a main shaft, a main shaft housing, a drilling tool, a power head and the above-mentioned drilling tool salvage device, wherein the motor is arranged on the ground, the motor is connected to the main shaft by driving, the end of the main shaft away from the motor is connected to the power head, the end of the power head away from the main shaft is fixedly connected to the drilling tool, the main shaft housing is covered outside the main shaft, the fixing mechanism is fixedly connected to the power head, the fixing mechanism is connected to the traction member, the end of the traction member away from the fixing mechanism is connected to the main shaft housing, and when the power head falls off, the traction member pulls the power head. With such arrangement, the motor transmits power to the main shaft, so that the main shaft rotates, the main shaft is connected to the power head by driving, so that the power head rotates, one end of the drilling tool salvage device is fixed to the main shaft housing, and the other end is fixedly connected to the power head, so that when the power head and the drilling tool fall off, the drilling tool salvage device can pull the power head and the drilling tool. The power head and the drilling tool are hung on the main shaft housing through the traction member, thereby realizing the salvage of the power head and the drilling tool.
[0015] The technical solution of the utility model is applied to provide a drilling tool salvage device, including a fixing mechanism and a traction member, wherein the fixing mechanism is sleeved on the outer periphery of the power head of the drilling rig, and the fixing mechanism is fixedly connected to the power head; one end of the traction member is connected to the fixing mechanism, and the other end of the traction member is connected to the main shaft housing of the drilling rig, and the traction member is used to pull the power head. With this solution, the fixing mechanism is sleeved on the outer periphery of the power head, and one end of the traction member is fixedly connected to the fixing mechanism, and the other end is connected to the main shaft housing of the drilling rig, so that the detached power head is pulled by the traction member and hung on the fixing mechanism, and will not fall off and be lost. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0017] Figure 1 A schematic structural diagram of a drilling tool salvage device provided by an embodiment of the utility model is shown;
[0018] Figure 2 A structural schematic diagram of a drilling tool salvage device provided by an embodiment of the utility model from another angle is shown;
[0019] Figure 3 Shows Figure 1 A schematic diagram of the structure of the first buckle plate of the drilling tool salvage device;
[0020] Figure 4 Shows Figure 1 A schematic diagram of the structure of the second gusset plate of the drilling tool salvage device;
[0021] Figure 5 Shows Figure 1 A schematic diagram of the structure of the plug-in plate of the drilling tool salvage device;
[0022] Figure 6 Shows Figure 1 A schematic diagram of the structure of the plug plate structure of the drilling tool salvage device.
[0023] The above drawings include the following reference numerals:
[0024] 10. Fixing mechanism; 11. First gusset plate; 12. Second gusset plate;
[0025] 21. Insert plate; 22. Support member; 23. Connecting plate;
[0026] 30. Traction parts;
[0027] 40. Spindle housing. DETAILED DESCRIPTION
[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0029] like Figures 1 to 6 As shown, an embodiment of the utility model provides a drilling tool salvage device, including a fixing mechanism 10 and a traction member 30. The fixing mechanism 10 is sleeved on the outer periphery of the power head of the drilling rig, and the fixing mechanism 10 is fixedly connected to the power head; one end of the traction member 30 is connected to the fixing mechanism 10, and the other end of the traction member 30 is connected to the main shaft housing 40 of the drilling rig, and the traction member 30 is used to pull the power head.
[0030] By adopting this solution, the fixing mechanism 10 is sleeved on the outer periphery of the power head, one end of the traction member 30 is fixedly connected to the fixing mechanism 10, and the other end is connected to the main shaft housing 40 of the drilling rig, so that the detached power head is pulled by the traction member 30 and hung on the fixing mechanism 10, and will not fall off and be lost.
[0031] like Figures 1 to 4As shown, the fixing mechanism 10 includes a first buckle plate 11 and a second buckle plate 12, and the first buckle plate 11 and the second buckle plate 12 are connected to form a ring structure. In this way, the first buckle plate 11 and the second buckle plate 12 are matched and fixedly connected to form a ring, which is sleeved on the outer periphery of the power head and fixedly connected to the power head.
[0032] like Figures 1 to 4 As shown, a first connecting hole is opened on the end surface of the first buckle plate 11 close to the second buckle plate 12, and a second connecting hole is opened on the end surface of the second buckle plate 12 close to the first buckle plate 11. The first buckle plate 11 and the second buckle plate 12 are fixedly connected through the first connecting hole and the second connecting hole.
[0033] In this way, a first connecting hole is provided on the end surface of the first buckle plate 11 close to the second buckle plate 12, and a second connecting hole is provided on the end surface of the second buckle plate 12 close to the first buckle plate 11, so that the first connecting hole and the second connecting hole are installed in coordination to fix the first buckle plate 11 and the second buckle plate 12 together.
[0034] In a specific embodiment of the present invention, the thickness of the first gusset plate 11 and the second gusset plate 12 are both greater than or equal to 80 mm. In this way, the thickness of the first gusset plate 11 and the second gusset plate 12 is large enough, so that the strength of the first gusset plate 11 and the second gusset plate 12 can bear the weight of the drilling tool, thereby preventing the first gusset plate 11 or the second gusset plate 12 from breaking during the pulling of the drilling tool.
[0035] like Figure 3 As shown, the first gusset plate 11 is a U-shaped plate, and the inner circle of the U-shaped plate matches the outer periphery of the power head. In this way, the inner circle of the U-shaped plate and the outer periphery of the power head are matched and installed, and the first gusset plate 11 can be fixed on the outer periphery of the power head.
[0036] In a specific embodiment of the present invention, the inner circle diameter of the U-shaped plate at one end close to the drill bit is larger than the inner circle diameter of the U-shaped plate at one end away from the drill bit, so that the inner circle of the U-shaped plate forms a slope, thereby making the U-shaped plate less likely to fall off the power head.
[0037] like Figure 3 As shown, the U-shaped plate includes two connecting arms and a middle plate. The end of the connecting arm facing away from the second buckle plate 12 is connected to the middle plate. A first connecting hole is opened on the end surface of the two connecting arms close to the second buckle plate 12. The first connecting hole is used to connect the U-shaped plate to the second buckle plate 12. A reserved hole is arranged axially of the two connecting arms, and the traction member 30 is passed through the reserved hole.
[0038] In this way, the U-shaped plate includes two connecting arms and a middle plate, and the end of the connecting arm away from the second gusset plate 12 is connected to the middle plate. The outer ring of the U-shaped plate can be chamfered, making the use of the U-shaped plate safer and not causing harm to the installer. The two connecting arms are provided with reserved holes in the axial direction, and the traction member 30 is inserted into the reserved holes, and the traction member 30 is fixed in the reserved holes to achieve the connection between the traction member 30 and the fixing mechanism 10.
[0039] In a specific embodiment of the present invention, the traction member 30 is a steel wire rope, the middle portion of the steel wire rope is fixed to the main shaft housing 40 of the drilling rig, and both ends of the steel wire rope are fixedly connected to the reserved holes of the two connecting arms respectively.
[0040] In this configuration, the traction member 30 is a steel wire rope, which has strong strength and toughness, so that the steel wire rope is not easy to break during the traction process. In addition, the cost of using the steel wire rope is low and the service life is long. The steel wire rope is folded in half, and the middle part is fixed to the main shaft housing 40, and the two ends of the steel wire rope pass through and are fixed to the reserved holes of the U-shaped plate. In a specific embodiment of the utility model, the middle part of the steel wire rope can be hung on the main shaft housing 40 or wound and fixed on the main shaft housing 40.
[0041] In a specific embodiment of the utility model, the diameter of the steel wire rope is greater than 50 mm. In this way, the diameter of the steel wire rope is greater than 50 mm, which ensures the strength and toughness of the steel wire rope, making it difficult for the steel wire rope to break during the process of pulling the drilling tool, thereby ensuring the safety of use.
[0042] Furthermore, the drilling tool salvage device also includes a fastener, which fixes the first gusset plate 11 and the second gusset plate 12. In this way, the fastener passes through the first connection hole and the second connection hole to fix the first gusset plate 11 and the second gusset plate 12 together, so that the strength of the connection is relatively large and it is not easy to loosen. In a specific embodiment of the utility model, the first gusset plate 11 and the second gusset plate 12 can be welded to make the connection more firm and not easy to be damaged.
[0043] Furthermore, the drilling tool salvage device also includes a plug plate structure, which is arranged on the drilling tool and is used to guide and fix the drilling tool so that the drilling tool moves forward in the drilling direction.
[0044] In this way, the plug plate structure is arranged on the drilling tool, so that the drilling tool can move along the inclination angle of the drilling tool when it moves forward in the drilling well without deflection. In a specific embodiment of the utility model, the plug plate structure is arranged on the ground.
[0045] like Figures 5 and 6As shown, the plug plate structure includes a plug plate member 21, a connecting plate 23 and two support members 22. The plug plate member 21 is U-shaped, and the plug plate member 21 is clamped in the clamping square groove of the drilling tool. The support members 22 are supported at the connection between the plug plate member 21 and the drilling tool. The support members 22 are arranged on both sides of the drilling tool. The connecting plate 23 connects the two support members 22, and the connecting plate 23 is arranged through the drilling tool.
[0046] With such arrangement, the plug-in plate 21 is clamped in the card-square groove of the drilling tool, so that the center line of the drilling tool is parallel to the center line of the drilling well, ensuring that the forward direction of the drilling tool is the same as the angle of the drilling well. There are two support members 22, which are arranged on both sides of the drilling tool to support the plug-in plate 21, so that the plug-in plate 21 is arranged perpendicular to the center line of the drilling tool. The connecting plate 23 is arranged through the drilling tool to connect the two support members 22, so that the two support members 22 can be fixed on the drill rod.
[0047] According to another aspect of the utility model, a drilling rig is provided, including a motor, a main shaft, a main shaft housing 40, a drilling tool, a power head and the above-mentioned drilling tool salvage device, the motor is arranged on the ground, the motor is connected to the main shaft driving, the end of the main shaft away from the motor is connected to the power head, the end of the power head away from the main shaft is fixedly connected to the drilling tool, the main shaft housing 40 is covered outside the main shaft, the fixing mechanism 10 is fixedly connected to the power head, the fixing mechanism 10 is connected to the traction member 30, the end of the traction member 30 away from the fixing mechanism 10 is connected to the main shaft housing 40, when the power head falls off, the traction member 30 pulls the power head.
[0048] In this arrangement, the motor transmits power to the main shaft, so that the main shaft rotates, and the main shaft is connected to the power head, so that the power head rotates. One end of the drilling tool salvage device is fixed to the main shaft housing 40, and the other end is fixedly connected to the power head, so that when the power head and the drilling tool fall, the drilling tool salvage device can pull the power head and the drilling tool. The power head and the drilling tool are hung on the main shaft housing 40 through the traction member 30, thereby realizing the salvage of the power head and the drilling tool. In a specific embodiment of the utility model, the power head is threadedly connected to the drilling tool.
[0049] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0051] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values of the parts and steps set forth in these embodiments do not limit the scope of the utility model. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.
[0052] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.
[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0054] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.
Claims
1. A drilling tool salvage device, characterized in that: include: A fixing mechanism (10), wherein the fixing mechanism (10) is sleeved on the outer periphery of a power head of the drilling rig, and the fixing mechanism (10) is fixedly connected to the power head; A traction member (30), one end of which is connected to the fixing mechanism (10), and the other end of which is connected to a main shaft housing (40) of a drilling rig, and the traction member (30) is used to pull the power head.
2. The drilling tool salvage device according to claim 1, characterized in that: The fixing mechanism (10) comprises a first buckle plate (11) and a second buckle plate (12), wherein the first buckle plate (11) and the second buckle plate (12) are connected to form a ring structure.
3. The drilling tool salvage device according to claim 2, characterized in that: A first connecting hole is provided on the end surface of the first buckle plate (11) close to the second buckle plate (12), and a second connecting hole is provided on the end surface of the second buckle plate (12) close to the first buckle plate (11). The first buckle plate (11) and the second buckle plate (12) are fixedly connected via the first connecting hole and the second connecting hole.
4. The drilling tool salvage device according to claim 2, characterized in that: The thickness of the first gusset plate (11) and the second gusset plate (12) are both greater than or equal to 80 mm.
5. The drilling tool salvage device according to claim 2, characterized in that: The first buckle plate (11) is a U-shaped plate, and the inner circle of the U-shaped plate matches the outer circumference of the power head.
6. The drilling tool salvage device according to claim 5, characterized in that: The U-shaped plate comprises two connecting arms and a middle plate, wherein one end of the connecting arm facing away from the second buckle plate (12) is connected to the middle plate, and a first connecting hole is provided on the end surface of the two connecting arms close to the second buckle plate (12), wherein the first connecting hole is used to connect the U-shaped plate to the second buckle plate (12), and a reserved hole is provided axially of the two connecting arms, and the traction member (30) is inserted into the reserved hole.
7. The drilling tool salvage device according to claim 6, characterized in that: The traction member (30) is a steel wire rope, the middle part of which is fixed to the main shaft housing (40) of the drilling rig, and the two ends of which are respectively fixedly connected to the reserved holes of the two connecting arms, and the diameter of the steel wire rope is greater than 50 mm.
8. The drilling tool salvage device according to claim 2, characterized in that: The drilling tool salvage device also includes a fastener, which fixes the first gusset plate (11) and the second gusset plate (12) together.
9. The drilling tool salvage device according to claim 1, characterized in that: The drilling tool salvage device also includes a plug plate structure, which is arranged on the drilling tool and is used to guide and fix the drilling tool so that the drilling tool moves forward in the drilling direction.
10. The drilling tool salvage device according to claim 9, characterized in that: The plug plate structure comprises a plug plate member (21), a connecting plate (23) and two supporting members (22); the plug plate member (21) is U-shaped, the plug plate member (21) is clamped in the clamping square groove of the drilling tool, the supporting members (22) are supported at the connection between the plug plate member (21) and the drilling tool, the supporting members (22) are arranged on both sides of the drilling tool, the connecting plate (23) connects the two supporting members (22), and the connecting plate (23) is arranged through the drilling tool.
11. A drilling rig, characterized in that: The invention comprises a motor, a main shaft, a main shaft housing (40), a drilling tool, a power head and a drilling tool salvaging device according to any one of claims 1 to 10, wherein the motor is arranged on the ground, the motor is drivingly connected to the main shaft, the end of the main shaft away from the motor is connected to the power head, the end of the power head away from the main shaft is fixedly connected to the drilling tool, the main shaft housing (40) is covered outside the main shaft, the fixing mechanism (10) is fixedly connected to the power head, the fixing mechanism (10) is connected to a traction member (30), the end of the traction member (30) away from the fixing mechanism (10) is connected to the main shaft housing (40), and when the power head falls off, the traction member (30) pulls the power head.