An Improved Machine for the Manufacture of Serrated Sheet Metal Cramps, and for Making Connections therewith.
Year: 1897

page_text: Date of Application, 15th May, 1897-Accepted, 10th July, 1897
An Improved Machine for the Manufacture of Serrated Sheet Metal
Cramps, and for Making Connections therewith.
I, HEINRICH WOLLHEIM, of Villa Simmig, No. 344 Wilhelminenstrasse, Loschwitz,
near Dresden, in the Kingdom of Saxony and German Empire, Gentleman, 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 :-
This Invention relates to machines for the manufacture of sheet metal cramps
having serrated edges for the connection of the edges or surfaces of boxes of Card
board or similar material and for fixing the cramps to boxes surfaces or edges.
The material from which the cramps are formed is a sheet metal strip of a width
equal to the length of the cramps to be produced.
In order that this Invention may be the better understood I now proceed to
describe the same, reference being had to the accompanying drawings and to the
letters and figures marked thereon.
Figures 1 and 2 are sectional views of the principal parts of the machine, and
Figures 3 to 16 show details thereof of two different forms of construction.
The front end of the sheet metal strip z is fed forwards by the rollers a. a.
Figure 2, and passes through a slot in the frame of the machine over the serrated
lower blade 6 of a pair of shears. The upper blade 61 formed correspondingly is
arranged on a vertically moveable slide c, see Figures 1 to 4. When the upper
blade b¹ descends, it cuts a serrated piece off the sheet metal strip. As the front
end of the sheet metal strip which has passed over the lower blade has been serrated
by the preceding cut, each piece which is cut off afterwards is serrated on the two
opposite edges, the teeth of one edge being opposite to the recesses of the opposite
edge, see Figure 6.
The cut off piece is carried by the slide c, during its descent, to a gridiron e
formed by a number of vertical plates arranged beside one another.
Figure 7, which is a part horizontal section through the frame of the machine,
shows a plan of the gridiron.
The gridiron e is provided with a grating f, Figures 23 and 4, which is moveable
horizontally and has half as many bars as the gridiron has openings, so that one
bar is situated in every alternate opening. Lugs r are pivotably arranged in the
free openings, the pointed extremities of which protrude over the sides of the
gridiron. The lugs r rest on one side on screws 7 and on the other side on flat
springs. Figure 8 shows a front elevation of the grating f, Figure 8*, which is
a similar view showing the introduction of the bars of the grating into the openings
of the gridiron.
When the piece cut off has reached the gridiron e, the grating is situated at
the rear end of the gridiron openings and its upper bar is behind the piece of sheet
metal which lies on the gridiron.
When then the slide c reascends, the grating f moves forwards, and its upper
bar pushes the sheet metal piece in front of it forwards on the gridiron e until the

page_text: points of the front teeth strike against the slip g', formed by the partial cutting
away of a roller g, inserted in the frame of the machine (Figures 4 and 9) and the
centre of the piece rests on a horizontally movable punch and the points of the
rear teeth are carried by the lugs r.
Two dies d d', Figures 2 to 5, are: arranged above the punch in the frame of
the machine, Figures 2 to 5. The die serves in combination with the before
mentioned punch to bend the sheet metal piece into cramp form and to bend the
teeth on the edges of the sheet metal piece into the position required for the sheet
metal cramp.
The die is designed to hammer the cramp to the edges or surfaces
to be connected. The die d has the form of a flat sleeve into which the die d¹ is
movably inserted see Figure 5, which shows a horizontal section through the
slide c and the dies d and d. The face of the die d is recessed saddle shape to
effect the connection of edges so that two working surfaces are formed oblique to
each other in the form of prongs of a fork. The face of the die d¹ which recedes
comparatively to the face of the die d is shaped according to the middle part of the
sheet metal cramp.
As soon as the piece of sheet metal has been passed over the punch h, as
described, the working faces of the descending die d strike the sheet metal piece and
bend it over the punch and then bend down the edge teeth of the sheet metal
piece which protrude over the punch along the sides of the punch, see..
· Figures 3
and 4. In this manner the piece of sheet metal strip has been changed to a sheet
metal cramp, as illustrated in section and side elevation Figure 10.
The dies which continue their descent after pushing back the punch carry
down the sheet metal cramp, which in consequence of its elasticity is held in the
saddle of the die d¹ until it strikes the card board box to be completed which is
placed on the anvil forming part of the machine. This anvil consists of two fixed
cheeks and a vertically movable centre piece . The die ¹ then continues the
travel alone and drives the edge teeth of the sheet metal cramp through the card
board the movable part ascending and bending any teeth which may protrude
through the card board see Figures 2 and 11.
During these operations the grating has returned into its original position.
When after the completion of these operations the dies d and d¹ have reascended,
the lugs and roller (the latter acting under the influence of a spring g² arranged on
the axes thereof) return into their original position. When finally the punch has
been moved forwards again, the action of the machine is repeated and the piece
of sheet metal cut off during the preceding descent of the slide and carried down
to the gridiron is brought within the action of the die and punch bent into cramp
form and ultimately brought on the other edge of the box placed on the anvil in
suitable manner.
The dies d di are operated in a known manner from the pulley shaft w of the
machine by eccentric discs in combination with angular levers. The slide c is
operated from one of the angular levers by means of a lever m connected thereto
by means of a hinge l. The movement of the punch is also effected by means of
an eccentric disc on the axle w Figures 1 and 2.
The grating is moved forwards by thumbs n situated on the ratchet wheel axle s
driving the rollers a for feeding the sheet metal strip see Figure 2 which thumbs
act on a plate cast on the slide f¹ which forms one piece with the grating.
Spiral springs serving for the withdrawal of the grating are arranged on the guiding
bolts connected with the slide and are compressed when the grating moves forwards.
The operation of the movable middle piece of the anvil is effected by means of
a thumb k on an axle k which receives its partial rotation through an arm k²
situated on it and an eccentric disc on the pulley axle w, see Figures 1 and 11.
If flat surfaces are to be connected by means of the cramps, the faces of the
dies punch and anvil are formed accordingly.
The machine constructed as before described produces sheet metal cramps with
serrated edges the teeth on one side of which are in alternate positions to those of
the other edge. However the machine may be constructed so that the teeth on

page_text: opposite edges of a cramp are opposite to one another. For this purpose the sheet
metal strip is introduced into the machine in the manner shewn in plan in
Figure 12, so that the direction of feed is at the same acute angle to the
longitudinal direction of the blade, which cats off the pieces as the side edges of
the teeth. The length of foed can be easily regulated so that the successive cuts
produce symmetrical pieces. This is shewn in Figures 13 and 14, Figure 13 shows
the sheet metal strip with one edge cut, the following cut being indicated in dotted
lines; Figure 14 shews the sheet metal strip with opposite teeth.
The bearings of the feed rollers are adapted to the changed directions of feed
and the corresponding wheel mechanism is formed accordingly. As the grating f
which carries the cut off piece over the punch must retain its vertical movement
relative to the blades, the plate cast in one piece with the slide f¹, on which the
thumb pieces n act, is placed obliquely, as shewn in Figures 15 and 16, in which
such plate is marked f³.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
clain is :-
1st. A machine for the manufacture of serrated sheet metal cramps, and for
connecting by means thereof edges and surfaces of boxes of card board or similar
material, in which an upper blade situated on a slide c cuts a piece serrated on
its edges from a sheet metal strip, which piece is carried by the descending slide c
on to a gridiron e, is then fed by means of a grating f inserted in the openings
of the said gridiron over a punch and is then placed below the working faces
of two dies d d¹, one of which is adapted to bend the sheet metal piece over the
punch into cramp form, and the other is adapted to hammer or close down the
finished cramp after the withdrawal of the punch on to the edges or surfaces of the
box placed on the anvil i which are to be connected.
2nd. In a machine as claimed in Claim 1 the construction of the gridiron e with
projecting lugs, pivotably arranged and spring pressed and opposite to such lugs
a roller g rotating against spring resistance and having a step g₁ in order to support
the edges of the sheet metal piece pushed over the punch h.
3rd. In a machine as claimed in Claim 1 an anvil constructed of two fixed side
cheeks and a movable middle piece which is lifted and adapted to bend over any
teeth, which may project throngh the Cardboard, when the sheet metal cramp is
hammered or closed on to the parts to be connected.
4th. Means for operating the grating claimed in Claim 1, consisting of thumbs n
on the axles of the ratchet wheel driving the feeding rollers for the sheet metal
strip, adapted to move the grating forwards, and spiral springs adapted to effect
the return movement which are compressed during the forward movement.
5th. A modified form of construction of the machine described hereinbefore in
which the sheet metal strip to be used is introduced at the same acute angle which
is formed by the edges of the teeth and the longitudinal direction of the cut in
order to produce cramps having the teeth on one edge opposite to the teeth on the
other edge.