US3034676A - Riveting machines - Google Patents

Description

May 15, 1962 A. SHACKELL RIVETING MACHINES 2 Sheets-Sheet 1 Filed Jan. 29, 1960 M G F Mm R Nw m R N M E r rm a; mu WW 9 May 15, 1962 Filed Jan. 29, 1960 A. SHACKELL 3,034,676

RIVETING MACHINES 2 Sheets-Sheet 2 3,034,676 Fatented May 15, 1962 3,034,676 RIVETING MACHINES Arthur Shackell, Weston Turville, England, assignor of one-half to The Bifurcated & Tubular Rivet Company Limited, Aylesbury, England, a company of Great Britain Filed Jan. 29, 1960, Ser. No. 5,444 Claims priority, application Great Britain Oct. 21, 1959 Claims. (Cl. 218-2) This invention relates to riveting machines, which term is intended to include machines for applying similar fixing devices, e.g. tacks.

In one form of known riveting machine, rivets (i.e. rivets, tacks or similar fixing devices) are fed one at a time into a holder which is movable towards a workpiece to be riveted as a riveting plunger pushes a rivet through the holder into the workpiece. One object of the present invention is to provide a machine of this form, in which the holder is held stationary until the plunger has engaged the head of the rivet and is then moved at a slower rate than the plunger to come to rest clear of the workpiece before the plunger pushes the rivet through the holder into the workpiece. A further object is to provide a machine in which movement of the holder, during the riveting stroke, is arrested without damage to the machine if the holder engages an obstruction.

According to the invention, there is provided a riveting machine, comprising a movable plunger, a holder adapted to support a rivet or similar fixing device between said plunger and a workpiece location, first means operable to move said plunger into engagement with the rivet and thereafter drive the rivet through a workpiece, and second means operable after the plunger has engaged the rivet to move said holder towards the workpiece at a speed slower than that of the plunger, the holder being maintained stationary prior to said engagement.

The invention will be described in relation to one embodiment thereof and with reference to the accompanying drawings, in which:

FIGURES 1 and 2 show side and end views respectively of the embodiment, FIGURE 2 being partly in section. FIG. 1a is a fragmentary view of a modification of the embodiment according to FIGS. 1 and 2.

Referring to the figures, a plunger bar 1 and a holder bar 2 are slidably mounted in a rigid frame member 3. At their lower ends, the plunger bar carries a plunger 4 and the holder bar carries, through a pair of leaf-spring arms 5, a holder 6. The arms 5 are secured to the holder bar by a screw and wing-nut assembly 7. Rivets are fed one at a time to the holder down a chute 8 and, as such an arrangement is well-known it will not be further described.

An operating lever 9, actuated by any suitable known means (not shown), is pivoted to the frame member at 10 and extends to engage at one end 9a in a channel-sectioned member 11 integrally formed at the upper end of the plunger bar. Said end of the lever 9 is of part-circular shape as shown, within the member 11, and pivoting of the lever effects sliding movement of the plunger bar relative to the frame member.

The upper end of the holder bar 2 is grooved to receive one end of a control lever 12, which lever normally rests on a peg-like projection 13 secured to the operating lever 9 and located between the pivot 10 and the end 9a of the lever 9. The other end of the lever 12 is urged downwardly by a tension spring 14 connected between the lever 12 and a post 15 fixed on a rigid frame 3. Lever 12 is provided with a depending abutment 16 which projects downwardly beyond the groove in the holder bar and serves to limit pivoting of the control lever relative to said bar.

Sliding movement of the holder bar 2 relative to the frame member 3 is limited by two stops 17 and 18 secured to the bar. Stop 17 abuts the under side of the frame member to limit upward movement of bar 2 and stop 18 abuts the top side of said member to limit downward movement of the bar.

The plunger bar 1 and holder bar 2 are both shown in their uppermost positions ready to commence a riveting stroke. With a rivet (not shown) positioned in the holder 6, operating lever 9 is pivoted so that the plunger bar, with the plunger 4, moves downwards. Consequent downward movement of the projection 13 permits control lever 12 to pivot relative to the holder bar, under the force of spring 14, until abutment 16 of lever 12 engages the holder bar. Thus, during the initial movement of the plunger 4 the holder 6 remains stationary, the engagement of abutment 16 with the holder bar being arranged to coincide with engagement of the plunger with the head of the rivet.

As projection 13 continues downwards, the control lever 12 acts as a fixed extension of the holder bar 2 and the latter, with the holder 6 commences to move downwards under the force of spring 14. Due to the location of projection 13, the holder moves at a slower speed than the plunger thereby allowing the plunger, with the rivet, to move through the holder. Towards the end of the riveting stroke, stop 18 abuts the frame member and prevents further movement of the holder so that, when the stroke is completed, relative positions of the plunger and bolder are as indicated by broken lines at 4a and 6a respectively.

Although not shown, it will be appreciated that a suitabie anvil is provided below the plunger so that, with a workpiece on the anvil, the rivet is secured in position in the workpiece at the end of the riveting stroke.

On the return stroke, abutment 16 remains in engagement with the holder bar 2 until stop 17 abuts the frame member. :Further upward movement of the holder bar is then prevented and the control lever 12 pivots to the position shown.

One advantage of a machine according to the invention is that, if the holder meets an obstruction (e.g. a misplaced workpiece) during its downward travel, it will resist the force of the spring 14 and stop, projection 13 moving out of contact with the control lever 12. During the following return stroke, the projection will re-engage the lever and the holder will be lifted clear of the obstruction.

According to a feature of the invention, the effective diameter of the projection 13 may be adjusted, thereby altering the distance between abutment 16 and the holder bar. This enables the time delay between commencement of movement of the holder and plunger bars to be altered. One means of adjusting the projection diameter is by the use of a sleeve 13a adapted to fit over the projection 13 between it and the control lever 12. With such an adjustable arrangement, the time delay can be chosen so that the shank of a rivet projects visibly through the bottom of the holder before the latter reaches its lowest position. This will permit an operator readily to locate a pierced workpiece on the rivet prior to riveting.

What is claimed is:

1. A riveting machine, comprising a movable plunger, a holder adapted to support a rivet between said plunger and a workpiece location, first means operable to move said plunger into engagement with the rivet and thereafter drive the rivet through a workpiece, second means controlled by said first means to be operated after the plunger has engaged the rivet, said second means moving said holder towards the workpiece at a speed slower than that of the plunger, the holder being maintained stationary prior to said engagement, a plunger bar carrying said a plunger, and a holder bar carrying said holder, said bars being mounted longitudinally slidable, said first means including an operating lever pivoted to a fixed pivot and engaging said plunger bar, pivoting of the operating lever producing longitudinal movement of the plunger bar, and said second means including a control lever pivoted to said holder bar for an initial limited pivotal movement relative thereto, means for positioning the control lever in dependence upon a pivotal movement of said operating lever so that the holder bar is maintained stationary during said initial limited pivotal movement of the control lever, and spring means moving said holder bar longitudinally in the same direction as the plunger bar upon completion of said limited pivotal movement of the control lever.

2. A machine according to claim 1, wherein said operating lever carries a projection located between said fixed pivot and the point of engagement with the plunger bar, said control lever extending past said projection towards the fixed pivot, said spring means are maintaining the control lever in contact with said projection.

3. A riveting machine, comprising a rigid frame member, plunger and holder bars supported by the frame member parallel to each other and individually lengthwise slidable relative thereto, a plunger secured at one end of the plunger bar, a holder secured at a corresponding end of the holder bar and serving to locate a rivet in the path of the plunger, an operating lever pivoted to the frame member and coupled to the other end of the plunger bar for reciprocating the plunger relative to a workpiece by pivoting said lever, a projection extending from the operating lever and located between the pivot of said lever and the coupling point thereof with the plunger bar, a control lever pivoted to the holder bar adjacent said other end of the plunger bar and slidably engageable intermediate its ends with said projection, stop means defining a limit position for pivotal movement of the control lever relative to the holder bar, spring means urging the control lever into contact with said projection so that the control lever tends to move as the operating lever pivots, and further stop means defining limit positions for a sliding movement of the holder bar and the holder in either direction; whereby, on pivoting of the operating lever, the plunger is moved from an initial position towards the holder, the latter remaining stationary due to pivoting of the control lever, and when the control lever reaches the limit of its pivoted movement, the holder is moved from one of its limit positions in the same direction as but at a slower speed than the plunger, and when the holder reaches its other limit position it becomes stationary while said projection is held out of contact with the control lever.

4. A machine according to claim 3, comprising a control means for varying the angle of the pivotal movement prior to reaching its limit position.

5. A machine according to claim 4, wherein said control means comprises a sleeve of a selected outer diameter fitting over said projection so as to lie between the projection and the control lever; whereby the angle of pivot of the control lever prior to reaching its limit position is controlled by the outer diameter of said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 2,373,436 Treciokas Apr. 10, 1945 FOREIGN PATENTS 561,726 Great Britain June 1, 1945

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