Year: 1898

page_text: I, JOHN FIELDING, of Upton Saint Leonards, in the County of Gloucester,
Engineer, do hereby declare the nature of this invention to be as follows:--
My invention relates to an improved method of operating the rivetting tool
slide of machines for rivetting, worked by hydraulic steam or pneumatic pressure.
Its principal objects are
1. To obtain economy of power.
2. To so proportion the pressure exerted upon the riveting tool, that it may
closely approximate at all points to the resistance offered by the rivet, whilst
the pressure exerted during a certain proportion of the concluding part of the
stroke may be practically constant, so that the final pressure upon the rivet may
not be appreciably affected by slight inequalities in the length of the rivets or in
the total thickness of the plates to be rivetted.
In carrying out my invention I operate a slide carrying the riveting tool by
means of a lever, pivotted to one arm of the riveting machine.
The lever is actuated by means of a roller, rolling along the edge of one of its
arms, the roller being guided either by a radius link or by a fixed roller path,
it is operated by a rod connected to the piston of a cylinder fixed to the riveting.
arm. Its movement during the riveting stroke is outwards, from a point near
the pivot centre towards the end of the arm of the lever, so that an increasing.
leverage is obtained as the roller proceeds along its path.
Furthermore, the angle, between the path of the roller, and the edge of the.
lever arm, becomes more and more acute as the leverage increases, so that the
roller and piston traverse a much longer distance for a given movement of
the rivetting tool at the end, than at the commencement of the stroke.
According to the proportion I find most suitable the piston during the first.
inch of its stroke, advances the rivetting tool, about an equal distance, whilst for
about the last half inch of the movement of the tool, the piston will traverse say
four to five inches.
I so shape that part of the roller path on lever arm upon which the roller acts.
whilst the rivetting tool is moving through that part of its stroke when constant
pressure is required, so that there is practically a constant ratio between the
travel of the piston and that of the tool slide.
The profile of the roller path on lever arm may be shaped to give any desired
curve of pressure upon the rivet.
In a pneumatic machine, I utilize the expansion of the compressed air which
has been already used to close the rivet for the purpose of effecting the return
stroke in the following manner:-
I connect the roller to the piston by a rod and crosshead, the rivet being closed
.

page_text: by the pressure of the air, acting upon the annular area of the rod side of the
piston.
After the rivetting stroke has been made the air is allowed to expand, into the
opposite end of the cylinder, which is fitted with a cover, so that an equilibrium of
pressure is formed on the two sides of the piston, but as the area is less upon the 5
rod side than upon the other, there is an unbalanced force due to the area of the
piston rod and the degree of air pressure, and this serves to affect the return
stroke.
Provo Rivetting machines:
I. JOHN FIELDING, of Belmont, Upton-Saint-Leonards, in the County of
Gloucester,. Engineer, do hereby declare the nature of this invention and in. what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
My invention relates to an improved method of operating the rivetting tool
slide of machines for rivetting, worked by hydraulic, steam,, or pneumatic pressure.
Its principal objects are:-
1. To obtain economy of power.
2. To so proportion the pressure exerted upon the rivetting tool that it may
closely approximate at all points to the resistance offered by the rivet, whilst
the pressure exerted during a certain proportion of the concluding part of the
stroke may be practically constant, so that the final pressure upon. the rivet may
not be appreciably affected by slight inequalities in the length. of rivets, or in
the total thickness of the plates to be rivetted.
In carrying out my invention I operate a slide carrying the rivetting tool by
means of a lever, pivotted to one arm of the rivetting machine.
The lever. is actuated by means of a roller rolling along the edge of one of its.
arms, the roller being guided either by a radius link or by a. fixed. roller path,
it is operated' by a. rod connected to the piston of a cylinder fixed to the rivetting
arm.
Its movement. during the riveting stroke is outwards from a point near the
pivot centre towards the end of the arm of the lever, so that an increasing leverage
is obtained as the roller proceeds. along its path.
Furthermore the angle between the path of the roller and the edge of the
lever arm becomes more and more acute as the leverage increases; so that the
roller and piston traverse a much longer distance for a given movement of
the riveting tool at the end than at the commencement of the stroke.
According to the proportion I find most suitable the piston during the first
inch of its stroke advances the riveting tool about an equal distance, whilst för
about the last half inch of the movement of the tool the piston. will. traverse say.
four to five inches.
The profile of the roller path on lever arm may be shaped to give any desired
curve of pressure upon the rivet.
In a pneumatic machine I utilize the expansion of the compressed air which
has been already used, to close the rivet for the purpose of effecting the return
stroke in the following manner:
I connect the roller to the piston by a rod and crosshead, the rivet being closed
4

page_text: by the pressure of air acting upon the annular area of, the rod. side of the
piston.
After the riveting stroke has been made the air is allowed to expand. into the
opposite end of the cylinder, which is fitted with a cover, so that an equilibrium of
pressure is formed on the two sides of the piston, but as tlie area is less upon the
rod side than upon the other there is an unbalanced force due to the area of the
piston rod and the degree of air pressure, and this serves to effect. 'the return
stroke.
DESCRIPTION OF THE. DRAWINGS.
Sheet 1 shows the construction of the machine, Fig: 1 being partly in side
elevation, and partly in section. Fig. 2 shews a transverse section on the line
A B. Figs. 3 and 4 being enlarged' sections of the valve and passages.
Sheet 2 Fig. 5 shews in diagram form the relative movements of the roller
actuated by the piston, and of the lever which. transmits.the motion to the rivetting
slide. In Fig. 1 the body of the machine is indicated by the numeral 1, 2 being
the rivetting slide, 3 the lever pivoting upon the pin 4, 5 6 are the rollers carried
upon the centre bolts attached to the crosshead 7, 8 is the inclined surface formed
upon the body 1. 9 and 10 are the rivetting dies,, 11 is the piston rod, 12 the
cylinder with the usual stuffing box through which the piston passes.
In Figs. 3 and 4 the slide valve is shewn by 13, 14 being the valve box, with
pressure inlet 15, 16 is the exhaust port leading to the outlet 17, 18 is the passage
leading to the front or piston rod end of cylinder, 19 is the passage leading to the
opposite end.
ACTION OF THE MACHINE.
Assuming the parts to be in the position indicated by Fig. 1, the slide valve
being in mid-position the pressure fluid, say compressed air, can only obtain
access to the valve box 14. By working the valve lever so as to move the latter
to the right into the position shewn in Fig. 3, the air enters the cylinder by the
passage 18 so as to act upon the annular surface of the piston driving the latter to
the right, which causes the rollers to act upon the surfaces of the inclined plane
and the edge of the lever, the short end of the lever pressing forward the riveting
die. During this stroke of the piston air escapes from the rear end of the cylinder
through passages 19 and 16 to the outlet port 17.
The compression of the rivet now being completed the valve is reversed until
it assumes the position in Fig. 4 whereby the ports 18 and 19 are connected to the
cavity in the slide valve 13, whilst the exhaust port 16 is closed.
By this means the compressed air which has been used to close the rivet is
allowed to expand into the opposite end of the cylinder, whereby owing to the
difference in the areas of the two sides of piston, the latter is returned into the
position shewn in Fig. 1. In practice I find it convenient to make the diameter
of the piston rod about one third of that of the cylinder.
Sheet 2, Fig. 5 shews the relative movements of the roller and the lever, their
respective paths being divided into 10 parts, in that of the roller these 10 parts are
all of equal length, but in the movement of the lever it will be seen that whilst
roller is moving from 0 to 5, or one half of its stroke, the angular movement of
the lever is such that the riveting slide has performed three fourths of its stroke,
thus leaving the second half of the roller movement to perform the last quarter of
that of the riveting slide.
It will furthermore be noted that owing to the curved form given to the face
of the lever the ratio of the movements of the lever and of the roller, from 5 to 10
is constant so that the pressure exerted upon the rivet during this part of the
movement will be constant providing that a constant pressure is exerted upon the
piston, which, under normal circumstances, will be the case.

page_text: Having now particularly described, and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. The construction, and arrangement substantially as described in relation to
Figs. 1 and 5 of a rivetting machine wherein a combined roller and lever are em-
5
ployed, the profile of the lever being specially formed so that whilst a rapidly
increasing pressure is brought to bear upon the rivet during the earlier stages of
compression, a sensibly constant closing pressure may be exerted upon-it, notwith-
standing slight variations in the length of the finished rivet.
2. In a rivetting machine operated by compressed air the arrangement of
cylinder, piston, valve and passages substantially as described and set forth in
relation to Figs. 1, 3 and 4 whereby the return stroke of the riveting slide is
effected by the expansion of the air used for compressing the rivet.
Dated this 7th day of November 1898.