BLIND RIVET FASTENING DEVICE
A steel ball 11 is housed in a hole 10 which extends from an inner wall toward an outer wall of a nose piece 3 and obliquely rearward with respect to a rivet inserting port 6 as shown by an arrow A. An elastic ring 12 elastically pushes the ball 11 from the outer wall toward the inner wall so that a part of the ball 11 may project into the port 6 whereby the mandrel 5 is grasped. As the hole 10 extends obliquely rearward with respect to the port 6, the ball 11 can move easily when the mandrel 5 travels in the inserting direction but the ball 11 is difficult to move when the mandrel 5 travels in the direction opposite to the inserting direction. As a result, the ball 11 blocks the mandrel 5 from travelling.
Latest NEWFREY LLC Patents:
This application claims priority, under 35 U.S.C. §119(a)-(d), to JP Patent Application No. 2011-63624 filed Mar. 23, 2011, the contents of which are incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe present invention relates to a blind rivet fastening device and, more specifically, to a nose piece at the front end of a blind rivet fastening device.
BACKGROUND OF THE INVENTIONA blind rivet fastening device includes a hollow nose housing for accepting a blind rivet, a nose piece provided on the front end of the nose housing and having a rivet insertion port for inserting the mandrel of a blind rivet, a jaw case provided adjacent to the rear of the nose piece so as to be able to move forward and rearward inside the nose housing and having an inner circumferential surface formed so the inner diameter becomes smaller towards the front end, a jaw provided inside the jaw case so as to hold the mandrel of a blind rivet inserted into the port and having an outer circumferential surface slidably contacting the inner circumferential surface of the jaw case, and a jaw pusher provided adjacent to the rear of the jaw and inside the nose housing for applying pressure to the jaw in the forward direction. In this blind rivet fastening device, the rearward movement of the jaw case with respect to the port and the narrowing of inner diameter of the jaw grasping the mandrel of the blind rivet in the jaw, and the rearward movement of the jaw case and the jaw grasping the mandrel ruptures the mandrel of the blind rivet and fastens a component-to-be-fastened with the rivet body of the blind rivet.
When a component-to-be-fastened is fastened with a blind rivet using a blind rivet fastening device, the mandrel of the blind rivet is inserted into an insertion port in the nose piece of the fastening device so that the rivet body pushes out from the nose piece. The fastening device is positioned so as to insert the rivet body into a mounting hole in the component-to-be-fastened, and the fastening device is operated to forcibly pull out the mandrel until it ruptures. The expanded and deformed sleeve of the rivet body fastens the blind rivet to the component-to-be-fastened. The ruptured mandrel is discharged to the rear of the blind rivet fastening device and is collected in a collector. The jaw case then returns to its starting position to load the next blind rivet. At this time, the ruptured mandrel is held by the jaw and a portion of the mandrel sometimes sticks out from the nose piece. In a pneumatic/hydraulic fastening device, the ruptured mandrel is suctioned and discharged to the rear using pneumatic pressure. Also, a holding means is proved to keep an inserted rivet from falling out. In a pneumatic-hydraulic fastening device, the rivet holding means ordinarily uses suction from pneumatic pressure. However, this is not economical because pneumatic pressure is needed between holding operations. In an electric fastening device, it is difficult to generation suction force, so another method has to be used to perform the holding operation.
One prior art means of holding a rivet is to attach an elastic ring able to elastically hold a blind rivet slidably along its center line in the blind rivet insertion port of the nose piece (Published Unexamined Patent Application No. 6-262290).
Another means of holding a rivet is to provide an engaging means for coming into contact with the mandrel of the inserted rivet and engaging the mandrel of the rivet. This engaging means is composed of an insertion hole provided to as to reach the insertion port from the outer circumferential surface of the nose piece, a bolt inserted into the insertion hole, and an elastic ring for pressing against the head of the bolt (Published Unexamined Patent Application No. 2008-168324).
Another means of holding a rivet is to suction and hold a rivet using pneumatic pressure (Published Examined Utility Model Application No. 55-38603).
In the rivet holding means of Patent Document 1 and Patent Document 2, the elastic ring applies elastic force perpendicularly to the center line of the blind rivet from the outer circumferential surface of the nose piece to the insertion port. Here, the elastic force applied to the blind rivet to move it in the insertion direction is the same as the elastic force applied to the blind rivet to move it in the direction opposite that of the insertion direction. Therefore, it can hold the rivet during insertion but cannot keep the mandrel from sticking out after fastening. When the elastic force is increased to keep the mandrel from sticking out, it becomes difficult to insert a rivet. Also, the rivet holding means in Patent Document 3 is uneconomical because it uses pneumatic pressure to suction and hold a rivet.
The object of the prior art documents is simply to hold a rivet. It is not to keep it from sticking out. When a simple rivet holding function is provided, complications occur because the mandrel sticks out after fastening. When held with the mandrel sticking out, it is difficult to load the next rivet.
BRIEF SUMMARY OF THE INVENTIONTherefore, an object of the present invention is to provide a blind rivet fastening device which makes it easy to insert a blind rivet in a nose piece, keep the inserted blind rivet from falling out before fastening, and prevent the ruptured mandrel from sticking out of the nose piece after fastening.
In order to achieve this object, the present invention is a blind rivet fastening device comprising a hollow nose housing for accepting a blind rivet, a nose piece provided on the front end of the nose housing and having a rivet insertion port for inserting the mandrel of a blind rivet, a jaw case provided adjacent to the rear of the nose piece so as to be able to move forward and rearward inside the nose housing and having an inner circumferential surface formed so the inner diameter becomes smaller towards the front end, a jaw provided inside the jaw case so as to hold the mandrel of a blind rivet inserted into the port and having an outer circumferential surface slidably contacting the inner circumferential surface of the jaw case, and a jaw pusher provided adjacent to the rear of the jaw and inside the nose housing for applying pressure to the jaw in the forward direction, the rearward movement of the jaw case with respect to the port and the narrowing of inner diameter of the jaw grasping the mandrel of the blind rivet in the jaw, and the rearward movement of the jaw case and jaw grasping the mandrel rupturing the mandrel of the blind rivet and fastening a component-to-be-fastened with the rivet body of the blind rivet, the blind rivet fastening device characterized in comprising a hole provided in the inner wall forming the port of the nose piece, an engaging means housed inside the hole, and a pressure-applying means for elastically pushing the engaging means towards the inner wall of the nose piece from the outer wall and causing a portion of the engaging means to protrude from the inner wall into the port, the hole extending from the inner wall towards the outer wall and rearward obliquely with respect to the rivet insertion port, and the front end of the hole opening into the port formed narrowly so the engaging means protruding into the port does not fall out.
In an embodiment of the present invention, the engaging means can be a spherical component, a cylindrical component, or a bolt-shaped component. Also, the pressure-applying means can be an elastic ring or a spring. The elastic ring can be an O-ring.
In the present invention, the hold accommodating the engaging means extends from the inner wall of the nose piece towards the outer wall and rearward obliquely with respect to the rivet insertion port. As a result, the engaging means can be easily moved rearward obliquely by the tip of the mandrel in the blind rivet moving in the insertion direction. However, because it is difficult for the engaging means to move rearward obliquely with respect to the mandrel moving in the direction opposite that of the insertion direction, movement of the mandrel is substantially prevented by the engaging means. In other words, the force needed by the mandrel to push up the engaging means after fastening is greater than the force needed by the inserted mandrel to push up the engaging means. Therefore, the present invention allows for the easy insertion of the blind rivet into the nose piece, and can hold the inserted blind rivet so that it does not fall out of the fastening device. Because the force needed by the mandrel to push up the engaging means after fastening is greater than the force needed by the mandrel held in the jaw to open the jaw, the mandrel is kept from sticking out of the nose piece after fastening. When the jaw has bitten into the mandrel and the force needed to open the jaw has become excessive, a large force applied from the mandrel to the engaging means can move the engaging means inside the hole rearward obliquely. The mandrel can then push up the engaging means after fastening. As a result, the fastening device does not break because the mandrel is sticking out from the nose piece after fastening.
The following is an explanation of an embodiment of the present invention with reference to the figures.
As shown in these figures, a nose housing 2 is provided at the front end of the blind rivet fastening device 1 to accept a blind rivet, and a nose piece 3 is provided at the front end of the nose housing 2. The nose piece 3 has an insertion port 6 for inserting the mandrel 5 of the blind rivet 4. As shown in
As shown in the partially enlarged cross-sectional views in
The following is an explanation of the operation of the blind rivet fastening device in an embodiment of the present invention, which will also be compared with a pneumatic-hydraulic blind rivet fastening device of the prior art.
First, the operation of the blind rivet fastening device in an embodiment of the present invention will be explained. In
In
In
In
In
The following is an explanation of the operation of a pneumatic-hydraulic blind rivet fastening device of the prior art. In
In
In
In FIG (D), the jaw case 7 moves forward as indicated by arrow E. At this time, because the ruptured mandrel 5 held in the jaw 8 moves forward, unlike in
Afterwards, in
Claims
1. A blind rivet fastening device comprising a hollow nose housing for accepting a blind rivet, a nose piece provided on the front end of the nose housing and having a rivet insertion port for inserting the mandrel of a blind rivet, a jaw case provided adjacent to the rear of the nose piece so as to be able to move forward and rearward inside the nose housing and having an inner circumferential surface formed so the inner diameter becomes smaller towards the front end, a jaw provided inside the jaw case so as to hold the mandrel of a blind rivet inserted into the port and having an outer circumferential surface slidably contacting the inner circumferential surface of the jaw case, and a jaw pusher provided adjacent to the rear of the jaw and inside the nose housing for applying pressure to the jaw in the forward direction, the rearward movement of the jaw case with respect to the port and the narrowing of inner diameter of the jaw grasping the mandrel of the blind rivet in the jaw, and the rearward movement of the jaw case and jaw grasping the mandrel rupturing the mandrel of the blind rivet and fastening a component-to-be-fastened with the rivet body of the blind rivet, the blind rivet fastening device characterized in comprising a hole provided in the inner wall forming the port of the nose piece, an engaging means housed inside the hole, and a pressure-applying means for elastically pushing the engaging means towards the inner wall of the nose piece from the outer wall and causing a portion of the engaging means to protrude from the inner wall into the port, the hole extending from the inner wall towards the outer wall and rearward obliquely with respect to the rivet insertion port, and the front end of the hole opening into the port formed narrowly so the engaging means protruding into the port does not fall out.
2. A blind rivet fastening device according to claim 1, wherein the engaging means is a spherical component.
3. A blind rivet fastening device according to claim 2, wherein the spherical component is a steel ball.
4. A blind rivet fastening device according to claim 1, wherein the engaging means is a cylindrical component.
5. A blind rivet fastening device according to claim 1, wherein the engaging means is a bolt-shaped component.
6. A blind rivet fastening device according to claim 1, wherein the pressure-applying means is an elastic ring.
7. A blind rivet fastening device according to claim 6, wherein the elastic ring is an O-ring.
8. A blind rivet fastening device according to any one of claim 1, wherein the pressure-applying means is a spring.
Type: Application
Filed: Mar 15, 2012
Publication Date: Sep 27, 2012
Applicant: NEWFREY LLC (Newark, DE)
Inventor: Daisuke MORI (Toyohashi-shi)
Application Number: 13/421,232
International Classification: B21J 15/30 (20060101);