Improvements in Hydraulic Rivetters.
Year: 1892

page_text: Date of Application, 7th Nov., 1892-Accepted, 13th May, 1893
COMPLETE SPECIFICATION.
Improvements in Hydraulic Rivetters.
I, VICTOR SCHÖNBACH of Karolinenthal near Prague (Bohemia) in the Empire
of Austro-Hungary 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 :-
The subject of this invention is a hydraulic rivetting machine the main advantages
of which are that it is provided with outer and inner plate-closing devices and
allows of a considerable saving of pressure-water as well as of the formation of
heads upon pins or studs unprovided with heads.
The machine comprises four rams. B is the rivetting ram which through the
Within the rivetting
medium of the guide-piece operates the cupping-tool s.
ram is arranged the plate-closing ram C, which by means of the guide-piece c moves
the outer plate-closing tool or crown' k, though it may also be utilized as a rivetting
piston if a cupping-tool is substituted for k. The small auxiliary piston H is
adapted to compensate all the idle or dead motion of the rams B and C with a
correspondingly reduced consumption of pressure-water. H also serves as a return
piston. In the present case H is connected with C, though if required, H may
also be rigidly connected with B. There is also on the side of the stationary
cupping-tool sa piston or ram C' submitted to constant pressure and therefore
retaining the inner closing-tool k' in the position indicated in the drawing. The
piston C does not shift till is submitted to a more powerful pressure than that
which C is capable of exercising. It is best to connect the ram C' with a separate
small accumulator loaded to an extent variable according to requirements, whereby
the pressure of C¹ may be adjusted according to the thickness of the plates to be
rivetted. The pistons or rams B C H are fed by means of two valves S and S¹
sustaining no load or weight and adapted to be operated by means of a hand-lever
common to both. When this hand-lever is in the normal position shown in Fig. 2,
all the pistons or rams are held back by the return-piston H, the front side of
which sustains a constant pressure and the position of the valves is such as to enable
the: pressure-water to be discharged. The discharge-pipe is connected with 'a
reservoir placed on a higher level.
When the hand-lever is moved from its initial position to an intermediate point of
its stroke, the lower valve S' is operated and pressure-water is admitted behind H,
and also owing to the axial perforation of the piston-rod, behind C. C and c then
alone: move forward, so that C can perform the rivetting operation provided. c:can
move freely in relation to and a cupping-tool is inserted into c instead of the
piece k. The free relative motion of c to b may however be limited or arrested: by
means of a removable plate p. In this case B in common with b and c move forwards
under the action of the auxiliary piston. H, while exhaust water follows behind B.
The cupping-tool in b moves forwards until it touches the rivet and during this idle
motion the auxiliary ram or piston H alone consumes water under pressure. At
this juncture (and not till then) the hand-lever is pushed further forward whereby
the slide S is set for pressure, i.e. pressure water is admitted behind B... It. here
meets the exhaust water filling the space and' the whole pressure of the ram B thus
loaded is now brought to bear on the tool s..
When however the removable plate p is of such dimensions that c is capable: of
displacement in relation to b to an extent z, c alone will move forwards while the
band-lever is in its initial position, until p and b meet, when both b and c will
complete the stroke under the action of the auxiliary piston with a correspondingly
reduced consumption of water under pressure. The relative motion of b and c may
be so limited that when the dead or idle movement st has been completed, the

page_text: cupping iron may directly strike the rivet, and the crown k also come into immediate
contact with the plate; so that will be in advance of s a distance of x and there
will be room between the said crown and the cupping-tool for the formation of the
head of the rivet. If the relative displacement of the two rams =, the cupping-
iron should in its initial position stand in front of the crown a distance of y === x.
Owing to this adjustment of parts where pins or bolts are employed, the material of
which the same are made, is properly distributed. This result is besides ensured
'by the fact that exactly the same relative position which exists between the crown
and the cupping-tool is also provided for on the side of the fixed cupping-tool s'
i.e. that k¹ is also in advance of s¹ a distance of which is just sufficient to allow
the head of the rivet to be formed between the two. From this it will be seen that
the distribution of the material of which the rivet is made is controlled to a nicety..
The inner plate-closing device however in addition to the distribution of material
has this main object that the moment when the dead motion of the piston or
driver B and C is completed, the blank between the pieces and is under the
action of the auxiliary piston retained in a stationary position so as to be incapable
of lateral displacement, even before the rivetting pin is flattened down. When
after this the formation of the rivet-heads is proceeded with, the pressure of the
blank firmly gripped in the machine increases to correspond to the maximum
pressure of Cor C₁ as the case may be, so that during the formation of the rivet-
heads a lateral displacement of the blanks becomes an utter impossibility. By this
means too the formation of the heads otherwise than straight is avoided and all
heads are exactly of the same size and properly centred.
'
The inner plate-closing device moreover offers the advantage that even when
ready-made rivets are employed, these may be inserted into the machine from
outside so that it is never necessary for a man to stand inside the article to be
rivetted say a boiler.
The operation of the machine will be readily apparent from the positions
illustrated by Figures 3, 4 and 5. Fig. 3 shows the operation under normal
conditions where the rivetting is performed by means of bolts or pins (without
-heads). Both the inner and outer closing-tools or crowns are set in position whereby
provision is made for the proper distribution of the material. The blank is placed
against the inner crown. When the dead movement st is completed, as indicated in
position III, the blank is securely gripped or compressed between the two crowns
or closing devices and the material of the pin on either side evenly distributed.
When the pressure-lever is pulled behind B, C₁ recedes while. C will be shifted
in B, so that both rivet-heads form at the same time (position IV). This however
will only happen when the pressure of C and that of "C' are equal, but when the
.pressure of C is less than that of C the head at s will form first, and C will not
recede within B until after the resistance of C' and of the bolt provided with a head
at s' has become more powerful than the pressure of C. Conversely when, the
pressure of C is less than that of C', a rivet-head will first form at s. For the
purposes of the general operation of the machine it is immaterial whether C and C¹
exercise equal or different pressures. From the foregoing it will be understood
.that rivetting by means of headless bolts or pins is possible even when C and C¹
are not under pressure. Figure 4 illustrates a case in which C is not under
pressure i.e. where the crown k is placed at a distance. In this case a head will form
at s first while the distribution of the material will be effected by the inner crown.
This arrangement may be applied in practice when C is employed as a rivetting
piston or driver, while the pressure of C¹ is made less than that of C. Where the
plate-closing is effected by means of a single instead of a double device, it will be
understood that the guiding and adjustment of the blank requires a great deal more
attention and care.
Figure 5 illustrates the operation of the machine where ordinary rivets are used.
In this case the outer-closing piece or crown k is somewhat removed; the rivetting
bolt is inserted from outside and the plate-closing is performed by the piece k¹.
From the operation as applied to the various cases herein mentioned, it will

page_text: be readily seen that the machine is capable of a great variety of combinations and
special provisions as regards the plate-closing operation and the pressure.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is,
1. In a hydraulic rivetting machine the employment of a double hydraulic device.
for compressing the plates to be rivetted one part of which is arranged on the same
side as the stationary cupping-tool and the other on the same side as the movable
cupping-tool by which arrangement in the case of a plain or headless bolt or pin
the following results are obtained
(a) A precise and correct distribution of the material of which the bolt or pin.
is made on either end of the blank.
(6) A secure and powerful guiding of the blank during the formation of the
heads the blank being only movable in the direction of the axis of the
cupping tool but incapable of any lateral displacement or oscillation so that
in no case are the rivet-heads formed otherwise than straight.
2. In a hydraulic rivetting machine as characterized in the first claim the
combination of the rivetting and plate-closing pistons with a movable cupping-tool
and an auxiliary piston the rivetting pistons or drivers being thereby moved forward
simultaneously by means of a comparatively small quantity of water under pressure.
up to the point at which the cupping-tools strike the pin to be headed while the
plate closing devices or crowns retain the blank in the position characterized in
paragraph b of the first claim.
Dated this 7th day of November 1892.
W. P. THOMPSON & BOULT,
Agents for the Applicant.