JPH024728Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to an improvement of a mandrel for expanding a pipe, which is press-fitted into a pipe when expanding the pipe.

(Prior Art) As is well known, in this type of pipe expanding mandrel, the size of the pipe expanding billet at the tip must be changed sequentially in accordance with the diameter of the pipe to be expanded, but each time the pipe diameter is changed, the entire mandrel is damaged. As a result, the operation of attaching and detaching the mandrel to a predetermined position on the tube expansion device becomes very complicated and takes a long time.

Therefore, in the past, as a means for easily changing the dimensions of the expanded billet, for example, as shown in FIG. The pin 2a to be inserted is screwed together, the billet 3 is fastened by the pin 2a, and when the billet 3 is to be replaced, the pin 2a can be removed without replacing the mandrel shaft 13a and only the billet 3 can be replaced. Means that make work possible have come into widespread use.

(Problems to be solved by the invention) However, in the conventional means, when exchanging the tube expansion billet 3, the mandrel shaft 1
Since the pin 2a screwed into the mandrel shaft 13a must be rotated each time to be attached and detached from the mandrel shaft 13a, the work is much simpler than the method of replacing the entire mandrel, but the pin 2a is still attached to the mandrel shaft 13a. The work of attaching and detaching the parts was complicated and took a considerable amount of time, and the workability was difficult.

The present invention was devised in view of the conventional problems as described above, and its purpose is to replace the expanding billet without having to do the complicated screwing and unscrewing of pins as in the past. The purpose of this invention is to allow the exchanging work of the expanding billet to be carried out using simpler working means.

(Means for Solving the Problems) The present invention does not attach the expanded billet directly to the mandrel shaft as in the past, but instead constructs a member that can be easily engaged and detached from the mandrel shaft, and attaches the expanded billet to the member. By providing this, the above-mentioned conventional problems are solved.

That is, the gist of the configuration of the present invention is that the set pin 1 has an expanded billet 3 at the tip, and the sleeve 7 is fitted on the rear side of the set pin 1 so as to be slidable in a non-rotating state with respect to the set pin 1.
and an elastic member 12 for biasing the sleeve 7 toward the rear end side of the set pin 1. An engaging protrusion 6 and an engaging hole 16 are provided at the rear of the sleeve 7, respectively, so that the set pin 1 and the mandrel shaft 13 can be connected to each other in a manner that prevents them from coming off through rotational displacement. Both the end portion and the tip of the mandrel shaft 13 are provided with engaging convex portions 10, 10 and an engaging groove 15 that can be engaged with each other in order to prevent both the sleeve 7 and the mandrel shaft 13 from rotating. They are set up separately.

(Function) Therefore, in the billet for tube expansion characterized by the above structure, in order to connect and attach the set pin 1 having the tube expander billet 3 to the mandrel shaft 13, it is necessary to connect the rear end of the set pin 1 and the mandrel shaft. 13
An engagement protrusion 6 and an engagement hole 16 provided at the tip of the
This can be done by rotating and engaging the sleeve 7 with the elastic member 1.
2, that is, toward the tip end of the mandrel shaft 13, to ensure that the engagement groove 15 engages the engagement convex portions 10, 10 of the rear end of the sleeve 7 and the tip of the mandrel shaft 13. As a result, inadvertent rotational displacement of the sleeve 7 can be prevented, so that the engagement between the engagement protrusion 6 that connects the set pin 1 and the mandrel shaft 13 and the engagement hole 16 can be ensured. As a result, the expanded billet 3 is securely connected to the mandrel shaft 13 via the set pin 1.

In addition, when removing the expanding billet 3 mounted on the mandrel shaft 13, it can be done in a completely reverse work process to the work process at the time of mounting, and the rear end of the sleeve 7 and the tip of the mandrel shaft 13 After releasing the engagement between the engagement protrusions 10, 10 and the engagement groove 15, the sleeve 7 and the set pin 1 are rotated so that the set pin 1 and the engagement protrusion 6 of the mandrel shaft 13 and the engagement hole 16 are disengaged. All that is required is to release the engagement.

(Example) Hereinafter, embodiments of the present invention will be described according to an example shown in the drawings.

In FIG. 1, reference numeral 1 designates a billet-equipped set pin having a hollow pipe expansion billet 3 fastened to its tip by means of a threaded shaft 2. 4a... and a male threaded portion 5, etc., and as shown in FIG. 3, a flat, substantially circular engagement protrusion 6 is protruded from the rear end.

As shown in FIG. 4, 7 has a female threaded portion 8 on its inner peripheral surface, two notched guide holes 9, 9 are carved in the tip thereof, and a protruding piece-like engaging portion is provided on the rear end side. A substantially cylindrical sleeve provided with mating convex portions 10, 10 is shown, and the sleeve 7 has a female threaded portion 8 on its inner peripheral surface.
is threaded through the male threaded portion 5 of the set pin 1 and slidably fitted onto the shaft portion of the set pin 1 on the rear side of the stepped portion 4. Reference numeral 11 indicates a rotation stop pin that is provided through the set pin 1 at a predetermined position, and both ends of the rotation stop pin 11 are connected to the sleeve 7 in order to prevent relative rotation between the set pin 1 and the sleeve 7. Notched guide hole 9 at the tip,
9 is engaged. Reference numeral 12 denotes a spring interposed between the front step of the female threaded portion 8 of the sleeve 7 and the step 4a of the set pin 1;
Reference numeral 2 urges the sleeve 7 toward the rear side in the direction of arrow A with respect to the set pin 1.

13 has a small diameter stepped portion 14 at the tip as shown in FIG.
Indicates a substantially cylindrical mandrel shaft having
An engagement groove 15 of a predetermined width is carved in the tip of the mandrel shaft 13, and the engagement groove 15
An engagement hole 16 having a circular side surface and having a dimension larger than the width of the groove 15 is connected to the rear (inner part) side of the groove 15 .
17 indicates a hole bored in the tip surface of the mandrel shaft 13 so as to overlap with the engagement groove 15;
The hole 17 has a depth that reaches the engagement hole 16.

The present embodiment has the above configuration, and its usage and operation will be explained next.

That is, with the sleeve 7 externally fitted onto the set pin 1 as shown in FIG. 2, first pull the sleeve 7 in the direction of arrow B against the elastic force of the spring 12 as shown in the same figure. With the rear end of the set pin 1 projecting a relatively long dimension from the sleeve 7, the engagement protrusion 6 on the rear end of the set pin 1 is inserted into the engagement groove 15 of the mandrel shaft 13 and the hole 1.
The sleeve 7 and the set pin 1 are then rotated 90 degrees so that the engagement protrusion 6 of the set pin 1 matches the shape of the engagement hole 16. Let it happen. Therefore, by the engagement between the engagement hole 16 and the engagement protrusion 6 of the set pin 1, the set pin 1 is connected to the mandrel shaft 13 in a manner that prevents it from coming off. However, in that state, set pin 1
When the mandrel shaft 13 rotates further with respect to the mandrel shaft 13, the engagement between the engagement protrusion 6 and the engagement hole 16 is easily released.

Next, in the above state, the sleeve 7 is attached to the spring 12.
The resilient force causes the sleeve 7 to retreat in the direction of arrow A and fit onto the small-diameter stepped portion 14 of the mandrel shaft 13. At this time, as shown in FIG. , 10 into the engagement groove 15 of the mandrel shaft 13, the sleeve 7 is fitted into the engagement groove 15 of the mandrel shaft 13 by the engagement action between the groove 15 and the engagement projections 10, 10.
The set pin 1 is reliably prevented from rotating with respect to the mandrel shaft 13, and as a result, the engagement protrusion 6 of the set pin 1 is rotated relative to the mandrel shaft 13.
This prevents the set pin 1 and the sleeve 7 from unduly detaching from the mandrel shaft 13 due to inadvertent release of the engagement state. Moreover, if the sleeve 7 is externally fitted onto the small-diameter stepped portion 14 of the mandrel shaft 13, the axial alignment of the sleeve 7 and the mandrel shaft 13 can be suitably performed by the fitting action of the two.

Therefore, the mandrel to which the tube expansion billet 3 is securely attached as described above can be suitably used without causing any hindrance to the prescribed tube expansion work.

Furthermore, when replacing the billeted set pin 1 again, first the set pin 1 and the sleeve 7, which have been connected and mounted on the mandrel shaft 13, are removed from the mandrel shaft 13, but this work is completely different from the time of installation. Reverse the process procedure, that is, first move the sleeve 7 forward in the direction of arrow B to release the engagement between the engagement protrusions 10, 10 of the sleeve 7 and the engagement groove 15 of the mandrel shaft 13, and then move the sleeve 7 and This is a very simple operation that involves rotating the set pin 1 90 degrees to disengage the engagement protrusion 6 of the set pin 1 from the engagement hole 16 of the mandrel shaft 13, and can be done quickly without using any tools. . In addition, when both the sleeve 7 and the set pin 1 are separated from the mandrel shaft 13, normally the sleeve 7 will not fall off from the rear side of the set pin 1 due to the elastic force of the spring 12. However, in this embodiment, since the inner end portions of the male threaded portion 5 and the female threaded portion 8, which are threaded on the sleeve 7 and the set pin 1, respectively, abut and are locked, the sleeve 7 does not come off from the set pin 1, and handling of both becomes easy.

In the above embodiment, the tube expansion billet 3 is provided as a separate member from the set pin 1, but the present invention does not limit the specific mounting structure of the tube expansion billet 3 to the set pin 1. There is no problem even if the billet 3 and the set pin 1 are integrally constructed from the same member.

Further, in the above embodiment, the engagement protrusion 6 at the rear end of the set pin 1 is made into a flat circular shape, and the shape of the engagement hole 16 of the other mandrel shaft 13 also matches the engagement protrusion 6. Although the engaging protrusion 6 and the engaging hole 16 according to the present invention have a predetermined shape, the specific shapes of the engaging protrusion 6 and the engaging hole 16 are by no means limited to this, and other shapes are also possible.
Of course, it is also possible to provide the engagement protrusion 6 at the tip of the set pin 3 and the engagement hole 16 at the rear end of the other set pin 1. In short, both the rear end of the set pin 1 and the tip of the mandrel shaft 13 are provided with an engaging protrusion 6 and an engaging projection 6 that can be freely engaged and disengaged from each other in order to prevent the two from coming off by rotational displacement of the two. It is only necessary that the common holes 16 be provided respectively.

Furthermore, in the above embodiment, the protruding engagement protrusions 10, 10 provided at the rear end of the sleeve 7
is engaged with the engagement groove 15 connected to the engagement hole 16 of the mandrel shaft 13, but the specific configuration of the engagement protrusion 10 and the engagement groove 15 according to the present invention is not limited to this. Alternatively, an engagement groove 15 may be provided at the tip of the mandrel shaft 13 separately from the engagement hole 16, or an engagement convex portion 10 may be provided at the mandrel shaft 13 on the other sleeve 7 side. Naturally, the engagement groove 15 may be provided. In short, both the rear end of the sleeve 7 and the tip of the mandrel shaft 13 are provided with engaging convex portions 10, 10 and an engaging groove 1 that can be engaged with each other in order to prevent both from rotating.
5 may be provided respectively, and the engaging protrusions 10
It does not ask about the specific number of such items.

Furthermore, the configuration of the other parts of the set pin 1 and the sleeve 7 in the present invention is not limited to the above-mentioned embodiments; for example, the male threaded part 5 and the female threaded part 8 to prevent the two from coming off are not essential requirements. Further, the means for preventing the sleeve 7 from rotating relative to the set pin 1 are also provided by the notched guide holes 9, 9 and the pin 1.
It is not limited to the combination with 1.

In addition, the present invention does not limit the type of the elastic member 12 for biasing the sleeve 7 against the set pin 1 to the spring as in the embodiment, nor does it limit the specific manner in which it is attached.

In addition, in the present invention, the design of the specific structure of each member constituting the tube expansion mandrel can be changed within the scope of the invention, and therefore, as shown in FIG. The shaft portion 31 is extended to the rear end position, and the other mandrel shaft 1
A hole 32 into which the shaft portion 31 is inserted is formed in the inner part of the engagement hole 16 of No. 3, so that the shaft portion 3
By fitting both the set pin 1 and the hole 32, the set pin 1
It is also possible to make design changes to eliminate the wobbling.

(Effects of the invention) As described above, the present invention enables a set pin having an expanded billet at its tip to be engaged with the tip of the mandrel shaft by rotational displacement of the set pin, thereby being connected in a manner that prevents the set pin from coming off. At the same time, a sleeve that can be engaged with the mandrel shaft in a non-rotating state is fitted onto the set pin, so that when the set pin and the mandrel shaft are connected, the set pin is inadvertently rotated with respect to the mandrel shaft, and both of them are prevented from rotating. The construction is such that it can reliably prevent the billet from coming off, so when attaching or detaching the expanded billet from the mandrel shaft, the rear ends of the set pin and sleeve must be engaged in predetermined positions at the tip of the mandrel shaft. It is a so-called one-touch operation that can be done without using any tools, and as a result, compared to the conventional means of screwing in and unscrewing the pin for tightening the tube expansion billet, the operation is extremely simple and takes less time. We have achieved the extraordinary effect of being able to significantly improve the work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a half-cut front view showing an embodiment of the mandrel according to the present invention. FIG. 2 is a cross-sectional view showing the state when attaching and detaching the expanded billet. Figures 3 to 5 show parts diagrams, Figure 3A is a front view of the main part showing the shape of the rear end of the set pin, Figure 4B is a plan view of the main part, and Figure 4A is a cross section of the sleeve. Figure 5B is a right side view of the figure, Figure 5A is a front view of the main part of the tip of the mandrel shaft, and Figure 5B is a left side view. FIG. 6 is a sectional view of main parts showing another embodiment. FIG. 7 is a sectional view of main parts showing a conventional example. 1... Set pin, 3... Expanded billet, 6...
...Engagement protrusion, 7...Sleeve, 10...Engagement convex portion, 12...Spring, 13...Mandrel shaft, 15...Engagement groove, 16...Engagement hole.

Claims (1)

[Claims for Utility Model Registration] 1. A set pin 1 having an expanded pipe billet 3 at its tip, a sleeve 7 externally fitted on the rear side of the set pin 1 so as to be slidable in a non-rotating state with respect to the set pin 1; An elastic member 12 is provided for urging the sleeve 7 toward the rear end of the set pin 1, and the set pin 1 and the elastic member 12 are provided at both the rear end of the set pin 1 and the tip of the mandrel shaft 13. The rear end portion of the sleeve 7 is provided with an engaging protrusion 6 and an engaging hole 16 that can be freely engaged with and detached from the mandrel shaft 13 so as to prevent the two from coming off by rotational displacement of the two. and the tip of the mandrel shaft 13 are provided with engaging protrusions 10, 10 and an engaging groove 1 that can be engaged with each other in order to prevent both the sleeve 7 and the mandrel shaft 13 from rotating.
A mandrel for expanding tubes, characterized in that 5 is provided respectively. 2. The means for stopping the rotation of the sleeve 7 on the set pin 1 includes notched guide holes 9, 9 provided along the axial direction of the sleeve 7, and the notched holes 9,
9. A mandrel for expanding tubes according to claim 1, which comprises a pin 11 penetrating the set pin 1 to engage with the set pin 1.