GB1603813A

GB1603813A - Blind riveting tool

Info

Publication number: GB1603813A
Application number: GB1521777A
Authority: GB
Original assignee: Spiralux Ltd
Current assignee: Spiralux Ltd
Priority date: 1978-04-27
Filing date: 1978-04-27
Publication date: 1981-12-02

Description

(54) BLIND RIVETING TOOL (71) We, SPIRALUX LIMITED, a British company of Bensham Grove, Thornton Heath Surrey, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a blind rivteting tool.

Known blind riveting tools have a nose which houses ajaw assembly. In use, the nose abuts the head of a rivet and the jaw assembly grips the mandrel of the rivet. By pulling the jaw assembly away from the head of the rivet, the rivet is distorted so as to effect the required riveting action. Further pulling of the jaw assembly results in the mandrel of the rivet snapping. Such hand tools incorporate a lever mechanism for pulling the jaw assembly relative to the nose, this lever mechanism being controlled by a pair of handles which are moved together to effect the pulling action. Such a lever mechanism is arranged to provide a mechanical advantage.Nevertheless in many types of blind riveting tool, the lever mechanism is such that several pulling actions have to be effected in order to provide the high force necessary to snap the mandrel of a rivet and thus complete the riveting operation. These multiple pulling actions (and hence multiple handle movements) are undesirable as being time-consuming and tiring.

The present invention provides a blind riveting tool comprising a body portion, a hollow nose, a jaw assembly reciprocable within the hollow nose by manually operable means via a lever mechanism, the jaw assembly being arranged to grip the mandrel of a rivet in the initial part of its working stroke and to pull the mandrel therewith as it executes its working stroke thereby upsetting the rivet head, wherein the lever mechanism comprises first and second handle levers, and first and second link means, the first and second handleleversbeing pivotally connected to one another and to the body portion, the first link means being pivotally connected at one end to the jaw assembly and at the other end to the first handle lever, and the second link means being pivotally connected at one end of the jaw assembly and at the other end to the second handle lever.

Preferably, the first link means and the second link means are connected to the jaw assembly by means of a common pivot pin.

Advantageously, first and second handles constitute the manually operable means, the first handle being connected to the first handle lever, and the second handle being connected to the second handle lever, the arrangement being such that the handles are in a first, widely divergent position at the start of the working stroke of the jaw assembly, and in a second, narrowly divergent position at the end of said working stroke.

Preferably, the lever mechanism is such that, at the start of the working stroke of the jaw assembly, the pivotal connections between the first link means and the first handle lever and between the second link means and the second handle lever are nearer the jaw assembly than the pivotal connection between the handle levers and the body portion, and, at the end of said working stroke, the pivotal connections between the first link means and the first handle lever and between the second link means and the second handle lever are further from the jaw assembly than the pivotal connection between the handle levers and the body portion.

The first link means may be constituted by a first pair of parallel links, and the second link means may be constituted by a second pair of parallel links.

Advantageously, the body portion is constituted by a pair of parallel plates. In this case, each link of the first and second pair of links may lie in a plane parallel to those of the plates constituting the body portion.

Preferably, said common pivot pin is constrained to move in the direction of the working stroke of the jaw assembly by its co-operation with elongate slots formed in the parallel plates constituting the body portion.

A heavy duty blind riveting tool constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the tool; Figure 2 is a front elevation of the tool, part of which is broken away to show its interior; Figures 3 and 4 are side elevations looking respectively in the directions of the arrows A and B of Figure 2; and Figure 5 is a schematic representation of the positions of various pivot pins of the tool during operation.

Referring to the drawings, Figure 1 shows a blind reveting tool having a body portion 1, a pair of handle levers 2 and 3 pivoted to the body portion by a pivot pin 4, and a pair of handles 5 and 6. Stops 5a and 6a are secured onto the insides of the handles 5 and 6 respectively, by means of screws Sb and 6b, these screws also serving to fasten the handles to their handle levers 2 and 3. The body portion 1 is constituted by front and back plates la and ib respectively, and by a top plate lc which sup ports a nose tube 7. The plates la, lb and ic are made of sheet metal. A nose 8 is fixed to the free end of the nose tube 7 and a replaceable nose bush 9 is screwed into the free end of the bose 8.

Ajaw assembly, constituted by jaws 10 and a jaw case 11, is slidably arranged within the nose tube 7 so that the jaws lie within the nose and the jaw casing extends beyond the other end of the nose tube and into the space between the front plate la and the back plate ib of the body portion 1. A first pair of links 12 interconnects the free end of the jaw case 11 and the handle lever 2, and a second pair of links 13 interconnects the free end of the jaw case and the handle lever 3. All four links 12 and 13 are pivotally connected to the jaw case 11 by means of a pivot pin 14, the pivot pin 14 being held in place by means of a grub screw 15. The pivot pin 14 is long enough to extend through elongate apertures 16 formed in the fomt and back plates la and l b.

The other ends of the links 12 are pivotally connected to the handle lever 2 by means of a pivot pin 17 which is held in position by means of a circlip 18. Similarly, the other ends of the links 13 are connected to their handle lever 3 by a pivot pin 19 and a circlip (not shown).

One link 12 and 13 of each pair of links thus lies adjacent and parallel to the front plate la of the body portion 1, the other two links 12 and 13 lying adjacent and parallel to the back plate Ib.

In use, the correct nose bush 9 for the rivet being used is screwed into the end of the nose 8. The handles 5 and 6 are then pushed apart until they are as wide apart as they will go.

The mandrel ofthe rivet is then inserted through the nose bush 9 and the entire tool pushed forward until the end of the nose bush rests against the head of the rivet. In this position, the free end portion of the mandrel lies within the jaws 10. Movement of the handles 5 and 6 towards each other causes the jaw assembly to move away from the nose bush 9. Initially, this movement causes the jaws 10 to grip the mandrel of the rivet, subsequent movement of the assembly pulling the mandrel with it. This causes upsetting of the rivet and eventually the snapping of the mandrel. If the mandrel does not snap by the time the stops Sa and 6a meet, thus preventing any further handle movement, the handles 5 and 6 are opened fully out and the procedure is repeated.

Referring now to Figure 5, the positions of the pivot pins 14, 17 and 19 relative to the fixed pivot pin 4 are shown at 14', 17' and 19' when the handles 5 and 6 are fully wide open, and at 14", 17" and 19" when the handles are closed, that is to say with the stops 5a and 6a touching. Thus, as the handles 5 and 6 move from their fully wide open position to their closed positions, each of the pivot pins 17 and 19 moves along an arc, and through an overcentre position with respect to the pivot pin 4.

At the same time, the pivot pin 14 to move along the apertures 16 results in an equalisation of the leverage applied to the jaw assembly from the two handles 5 and 6. Usually more force is applied to one handle than the other, and this provision prevents any unbalance which this might tend to cause, and hence improves operation of the tool.

WHAT WE CLAIM IS: 1. A blind riveting tool comprising a body portion a hollow nose, a jaw assembly reciprocable within the hollow nose by manually operable means via a lever mechanism, the jaw assembly being arranged to grip the mandrel of a rivet in the initial part of its working stroke and to pull the mandrel therewith as it executes its working stroke thereby upsetting the rivet head, wherein the lever mechanism comprises first and second handle levers, and first and second link means, the first and second handle levers being pivotally connected to one another and to the body portion, the first link means being pivotally connected at one end to the jaw assembly and at the other end to the first handle lever, and the second link means being pivotally connected at one end of the jaw assembly and at the other end to the second handle lever.

2. A tool as claimed in Claim 1, wherein the first link means and the second link means are connected to the jaw assembly by means of a common pivot pin.

3. A tool as claimed in Claim 1 or Claim 2, wherein first and second handles constitute the manually operable means, the first handle being connected to the first handle lever, and the second handle being connected to the second handle lever, the arrangement being such that the handles are in a first, widely divergent position at the start of the working stroke of the jaw assembly, and in a second, narrowly divergent position at the end of said working stroke.

4. A tool as claimed in any one of Claims 1 to 3, wherein the lever mechanism is such that, at the start of the working stroke of the jaw assembly, the pivotal connections between the first link means and the first handle lever and between the second link means and the second handle lever are nearer the jaw assembly than the pivotal connection between the handle levers and the body portion, and, at the end of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figure 5 is a schematic representation of the positions of various pivot pins of the tool during operation. Referring to the drawings, Figure 1 shows a blind reveting tool having a body portion 1, a pair of handle levers 2 and 3 pivoted to the body portion by a pivot pin 4, and a pair of handles 5 and 6. Stops 5a and 6a are secured onto the insides of the handles 5 and 6 respectively, by means of screws Sb and 6b, these screws also serving to fasten the handles to their handle levers 2 and 3. The body portion 1 is constituted by front and back plates la and ib respectively, and by a top plate lc which sup ports a nose tube 7. The plates la, lb and ic are made of sheet metal. A nose 8 is fixed to the free end of the nose tube 7 and a replaceable nose bush 9 is screwed into the free end of the bose 8. Ajaw assembly, constituted by jaws 10 and a jaw case 11, is slidably arranged within the nose tube 7 so that the jaws lie within the nose and the jaw casing extends beyond the other end of the nose tube and into the space between the front plate la and the back plate ib of the body portion 1. A first pair of links 12 interconnects the free end of the jaw case 11 and the handle lever 2, and a second pair of links 13 interconnects the free end of the jaw case and the handle lever 3. All four links 12 and 13 are pivotally connected to the jaw case 11 by means of a pivot pin 14, the pivot pin 14 being held in place by means of a grub screw 15. The pivot pin 14 is long enough to extend through elongate apertures 16 formed in the fomt and back plates la and l b. The other ends of the links 12 are pivotally connected to the handle lever 2 by means of a pivot pin 17 which is held in position by means of a circlip 18. Similarly, the other ends of the links 13 are connected to their handle lever 3 by a pivot pin 19 and a circlip (not shown). One link 12 and 13 of each pair of links thus lies adjacent and parallel to the front plate la of the body portion 1, the other two links 12 and 13 lying adjacent and parallel to the back plate Ib. In use, the correct nose bush 9 for the rivet being used is screwed into the end of the nose 8. The handles 5 and 6 are then pushed apart until they are as wide apart as they will go. The mandrel ofthe rivet is then inserted through the nose bush 9 and the entire tool pushed forward until the end of the nose bush rests against the head of the rivet. In this position, the free end portion of the mandrel lies within the jaws 10. Movement of the handles 5 and 6 towards each other causes the jaw assembly to move away from the nose bush 9. Initially, this movement causes the jaws 10 to grip the mandrel of the rivet, subsequent movement of the assembly pulling the mandrel with it. This causes upsetting of the rivet and eventually the snapping of the mandrel. If the mandrel does not snap by the time the stops Sa and 6a meet, thus preventing any further handle movement, the handles 5 and 6 are opened fully out and the procedure is repeated. Referring now to Figure 5, the positions of the pivot pins 14, 17 and 19 relative to the fixed pivot pin 4 are shown at 14', 17' and 19' when the handles 5 and 6 are fully wide open, and at 14", 17" and 19" when the handles are closed, that is to say with the stops 5a and 6a touching. Thus, as the handles 5 and 6 move from their fully wide open position to their closed positions, each of the pivot pins 17 and 19 moves along an arc, and through an overcentre position with respect to the pivot pin 4. At the same time, the pivot pin 14 to move along the apertures 16 results in an equalisation of the leverage applied to the jaw assembly from the two handles 5 and 6. Usually more force is applied to one handle than the other, and this provision prevents any unbalance which this might tend to cause, and hence improves operation of the tool. WHAT WE CLAIM IS:

1. A blind riveting tool comprising a body portion a hollow nose, a jaw assembly reciprocable within the hollow nose by manually operable means via a lever mechanism, the jaw assembly being arranged to grip the mandrel of a rivet in the initial part of its working stroke and to pull the mandrel therewith as it executes its working stroke thereby upsetting the rivet head, wherein the lever mechanism comprises first and second handle levers, and first and second link means, the first and second handle levers being pivotally connected to one another and to the body portion, the first link means being pivotally connected at one end to the jaw assembly and at the other end to the first handle lever, and the second link means being pivotally connected at one end of the jaw assembly and at the other end to the second handle lever.

said working stroke, the pivotal connections between the first link means and the first handle lever and between the second link means and the second handle lever are further from the jaw assembly than the pivotal connection between the handle levers and the body portion.

5. A tool as claimed in oany one of Claims 1 to 4, wherein the first link means is constituted by a first pair of parallel links, and the second link means is constituted by a second pair of parallel links.

6. A tool as claimed in Claim 5, wherein the body portion is constituted by a pair of parallel plates.

7. A tool as claimed in Claim 6, wherein each link of the first and second pair of links lies in a plane parallel to those of the plates constituting the body portion.

8. A tool as claimed in Claim 7, wherein the means whereby said first link means and said second link means are pivotally connected at one end of said jaw assembly is a common pivot pin which is constrained to move in the direction of the working stroke of the jaw assembly by its co-operation with elongate slots formed in the parallel plates constituting the body portion.

9. A blind riveting tool substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 4 of the accompanying drawings.