[0001] The present invention concerns a tool for tying metal bars, in particular iron bars
used for making the cage-like structures that make up the reinforcement of concrete
castings.
[0002] It is known that the reinforcement of concrete castings is constructed with cage-like
mesh structures comprising metal bars connected to each other at their crossing points
by tying them with metal wire.
[0003] According to a known technique, the tying operations are carried out manually by
means of pliers with which the ironworker twists the wire around the metal bars at
their crossing points and then, after twisting it, cuts the ends that protrude from
the area around which the wire has been twisted.
[0004] This known technique poses a first drawback, constituted by the fact that the tying
operations, being made manually, are long and complex to carry out.
[0005] A further drawback lies in that it is increasingly difficult to find expert ironworkers
on the market.
[0006] In order to overcome these drawbacks, make the tying operation rapid and allow it
to be carried out even by unskilled personnel, portable manual tools have been developed,
which are equipped with pliers that clamp a U-shaped metal clip around the metal bars.
[0007] These tools allow the bars to be tied more quickly, even by unskilled personnel,
but the clamping force of the metal clip around the bars is not sufficient and this
does not guarantee the stability of the structure.
[0008] Once the tying operation has been completed, therefore, the structure tends to deform
easily and therefore is difficult to transport.
[0009] Tying tools of the type described in patent
US5431196 are also known, which are provided with jaws inside which the bars to be tied are
inserted and with a rotary spindle that winds a metal wire around the bars at their
point of intersection, after the wire has been inserted in special crossed seats created
in the spindle itself.
[0010] The tool described in the patent mentioned above has the drawback of being difficult
to construct, due to the need to provide the spindle with the seats for the passage
of the metal wire.
[0011] A second drawback is represented by the fact that it is difficult to insert the wire
in the seats each time the tool is used.
[0012] A further drawback is constituted by the fact that the tool tends to jam often during
use and therefore is not sufficiently reliable.
[0013] A further and equally important drawback lies in that the cutting device, which is
provided with a pair of opposite rollers for cutting the wire, is complex to construct
from a kinematic point of view.
[0014] Patent
US5217049 is also known, concerning a tying tool with jaws that is differentiated from the
previous one due to the fact the wire is not crossed inside the spindle, but outside,
by means of a conical guide.
[0015] Also this patent, like the one previously described, poses the drawback that the
mechanical parts are difficult to make, since in any case it is necessary to create
seats for guiding the metal wire on the profiles of the cone and of the spindle.
[0016] Furthermore, the cutting system remains difficult to construct, since it consists,
also in this case, of two opposite rollers.
[0017] Another tying tool is described in the Patent EP 1 440 746 and presents the drawback to be provided with a rotary spindle and pliers for clamping
the metal wire which are difficult and expensive to be constructed and sometimes not
sufficiently reliable.
[0018] Embodiments of tools for tying metal bars are also known, which are equipped with
jaws where the bars to be tied are inserted and with rotary pliers between whose jaws
the wire is passed.
[0019] The pliers clamp the metal wire and then, rotating on their own axis, twist it around
the bar crossing point. The wire is cut by a pair of blades that move one against
the other.
[0020] All the known tools described above pose the drawback of having complex kinematic
mechanisms for transforming the rotary motion generated by the motor into the opening
and closing motion of the pliers' jaws, the rotary motion of the pliers for twisting
the wire and the movement of the pair of blades that cut the wire.
[0021] Furthermore, all the said tools are provided with a single motor that generates all
the necessary movements and this involves the need to provide for kinematic means
suited to transform the single rotary motion produced by the single motor into more
rotary and/or alternated motions to be transferred to the various moving members.
[0022] The known tying tools mentioned also pose the drawback that their wire bending means
often tend to tangle the wire.
[0023] Furthermore, also the wire cutting units are not sufficiently reliable, besides being
expensive and difficult to construct.
[0024] Another, equally important drawback that is common to all the mentioned tools is
constituted by the fact that for the tying operation they require a special, expensive
metal wire that is supplied exclusively by the individual manufacturers of the tools.
[0025] The object of the present invention is to overcome all the drawbacks described.
[0026] In particular, it is a first object of the invention to construct a portable tool
for tying metal bars that is equipped with means for winding the metal wire around
the bars that are easier to make than the winding means provided in the tying tools
carried out according to the known art.
[0027] It is a further object of the invention to carry out a portable tool for tying metal
bars that is provided with more reliable wire bending means than those present in
tying tools of known type.
[0028] It is a further object of the invention to carry out a tool for tying metal bars
which is provided with a wire cutting unit that is more reliable than the cutting
units present in the tying tools of known type.
[0029] It is a further aim of the invention to carry out a tying tool provided with kinematic
mechanisms for operating the moving parts that are simpler than those present in the
tying tools carried out according to the known art.
[0030] It is another, not less important object of the invention to provide a tying tool
where for tying the bars it is possible to use a common metal wire of the type available
on the market.
[0031] The objects mentioned above have been achieved through the construction of a tying
tool suitable for tying bars with mainly longitudinal development, in particular iron
rods for reinforced concrete, according to the contents of claim 1.
[0032] Other details of the tying tool that is the subject of the invention are described
in the dependent claims.
[0033] According to the description provided here below, the wire winding means comprise
a rotary spindle associated with a rotary head provided with pliers with openable
jaws for holding the metal wire and winding it in turns around the metal bars.
[0034] The metal wire cutting unit is set moving by the rotation of the winding means and
is positioned at the level of the wire bending means.
[0035] Different embodiments of the wire cutting unit and of the wire bending means are
possible.
[0036] According to the invention, the tool is provided with a main motor for rotating the
winding means and an auxiliary motor for feeding the wire.
[0037] Advantageously, the simpler construction of the tool that is the subject of the invention
compared to the equivalent tools of known type makes it more reliable to use and therefore
less subject to jamming, so that it requires less maintenance.
[0038] Still to advantage, the use of common metal wire to tie the bars ensures savings
on the purchase of the wire itself.
[0039] Still advantageously, the presence of two separate motors, one for winding the wire
turns around the bars and one for feeding the wire, ensures greater reliability and
longer duration of the tool.
[0040] The objects and advantages described above will be highlighted in greater detail
in the description of a preferred embodiment of the invention that is supplied as
an indicative, non-limiting example with reference to the enclosed drawings, wherein:
- Figure 1 shows a longitudinal section of the tying tool that is the subject of the
invention;
- Figure 1 a shows a detail of Figure 1;
- Figures 2 and 3 are two different axonometric views of the front of the tool of Figure
1;
- Figure 4 shows a detail of Figure 2;
- Figure 5 shows the detail shown in Figure 4 in a different operating position;
- Figure 6 shows an axonometric view of another detail of the tool that is the subject
of the invention;
- Figure 7 is an exploded view of the detail shown in Figure 6;
- Figures from 8 to 13 show six axonometric views of the tool of the invention in six
different operating stages;
- Figure 14 shows two bars tied using the tool of the invention;
- Figure 15 shows a longitudinal section of a construction variant of the tying tool
that is the subject of the invention;
- Figure 15a shows a detail of Figure 15;
- Figures 16 and 17 are two different axonometric views of the front of the tool of
Figure 15;
- Figure 18 shows a detail of Figure 16;
- Figure 19 shows the detail shown in Figure 18 in a different operating position;
- Figure 20 shows an axonometric view of another detail of the construction variant
of the tying tool that is the subject of the invention;
- Figure 21 is an exploded view of the detail shown in Figure 20;
- Figures from 22 to 27 show six axonometric views of the tool of the invention in six
different operating stages.
[0041] The tool 1 that is the subject of the invention can be seen in its entirety and in
longitudinal section in Figure 1 and also in Figures from 2 to 5, which show details
of the same in front axonometric view.
[0042] It is preferably used to tie together metal bars
Ba, Bb visible in the Figures 1 and 14 to make cage-like structures for concrete reinforcements.
[0043] It is evident, however, that the tool of the invention can be used also to tie metal
rods of a different nature and for different purposes.
[0044] It can be observed in particular that the tool
1 comprises a frame
2 with a handgrip
3, which supports a reel
4 on which the metal wire
F for tying the bars
Ba, Bb is wound.
[0045] A feed unit
5 unwinds the metal wire F from the reel
4 and makes it advance towards wire bending means
6 that shape it to form one or more turns
S around the above mentioned bars and at the same time also between means
7 suited to wind the turns
S around the above mentioned bars at their crossing point.
[0046] It is also possible to notice the presence of a unit
8 for cutting the metal wire
F, positioned at the level of the wire bending means
6. Power means, indicated as a whole by
9, of the winding means 7 and of the feed unit
5 cooperate with control means indicated by
10.
[0047] The reel
4 on which the metal wire
F is wound is supported by a pin
11 that, as can be observed, is fixed to and projects from the frame
2, the reel being free to rotate with respect to said pin according to the axis
X defined by the pin
11 itself.
[0048] The feed unit
5 of the metal wire
F is positioned immediately downstream of the reel
4, as shown in Figure 1, and comprises a pair of gear wheels
12, 13 that mesh with each other and between which the wire
F itself is included.
[0049] In particular, Figure 1a shows that both gear wheels
12, 13 are provided with a circumferential groove
14 containing the metal wire
F, whose profile, in cross section, can be conjugated with the profile of the metal
wire itself. The gear wheels
12, 13 cooperate with a reduction kinematic mechanism indicated as a whole by
15 that can be observed in Figure 3 and that sets them rotating.
[0050] It comprises a bevel gear
18 that sets rotating an intermediate shaft
17, passing through the frame
2, whose end is coupled with the gear wheel
12. The bevel gear
18, as shown in Figure 3, is positioned on the side opposite the gear wheels
12, 13 and is connected to an auxiliary motor
19 belonging to the above mentioned power means
9.
[0051] It can also be observed that downstream of the pair of gear wheels
12, 13 there is a tubular element
20 for guiding the wire, provided with a hole sized in such a way as to ensure optimal
guide and optimal control of the wire
F while it advances.
[0052] Engaging and disengaging means
21 for the gear wheels
12, 13 are also provided, which comprise a lever
22 hinged to the central part of the frame
2 through a pin
23, wherein said lever supports at one end
22a the pin of one of the gear wheels, for example the gear wheel
13, while its opposite end
22b on one side counteracts a cam element
24 provided with a manoeuvring rod
25 and on the other cooperates with elastic means
26 fixed to the frame
2.
[0053] As regards the wire bending means
6, it can be observed in particular in Figures from 2 to 5 that they comprise a wire
bending channel
27 positioned downstream of the feed unit
5 at the side of a wire bending jaw
28 suited to receive the wire
F coming out of the wire bending channel
27 and to shape it to form one or more of the above mentioned turns
S.
[0054] The wire bending channel
27, in particular, is positioned downstream of the feed unit
5 and is created in a wire bending plate
29 associated with the frame
2, to which the wire bending jaw
28 is fixed, against and above the wire bending channel
27.
[0055] During the bending step, the wire bending channel
27 controls the wire in such a way as to reduce the risk of tangling during use of the
tool, thus increasing its reliability compared to the known tools available on the
market and in particular compared to the tools described above.
[0056] The cutting unit
8 is associated with the wire bending means
6 and with the wire bending plate
29 in which the wire bending channel
27 is created.
[0057] More precisely, the cutting unit
8 comprises a cutting blade
30 that is mechanically connected to shifting kinematic means indicated as a whole by
31 and is slidingly fitted in a blade holding channel
32 that intersects the wire bending channel
27, being created at the level of the upper part of the wire bending plate
29.
[0058] In particular, the cutting blade
30 is provided at one end with a rack
33 that is coupled with the shifting kinematic means
31 visible in Figures 3, 4 and 5 that cause its longitudinal movement according to the
direction
Y defined by the blade holding channel
32.
[0059] Furthermore, it can be observed that the cutting blade
30 has, in intermediate position, a recess
34 that houses the wire F to be cut when it comes out of the wire bending channel
27 and defines an inclined cutting edge
35.
[0060] The shifting kinematic means
31 comprise a toothed pinion
36, supported by the frame
2, which meshes with the rack
33 of the cutting blade
30 and is coupled with rotation levers
37 cooperating with thrust means
38 associated with the means
7 for winding the turns
S around the bars
Ba, Bb, as will be described in detail below.
[0061] The movement of the rotation levers
37 is made yielding by elastic mean
39 constituted by a spring
39a.
[0062] The movement of the cutting blade
30 controlled by the blade holding channel
32 and by the shifting kinematic means
31, together with the special profile of the inclined cutting edge
35 and of the recess
34, make the cutting operation more reliable compared to the tying tools of known type.
[0063] The winding means
7 are visible in particular in Figures from 5 to 7 and according to the invention they
comprise:
- a spindle 40 belonging to the power means 9;
- a rotary head 41 fixed to the spindle 40;
- a rotary counter-head 42 idly connected to the end 40a of the spindle 40 and axially opposing the rotary head 41;
- one pair of pliers 43 associated with the rotary counter-head 42 and suited to house the turns S of wound wire F;
- elastic means 44 interposed between the rotary head 41 and the rotary counter-head 42;
- cam means 45 present in the rotary head 41 for opening and closing the pliers 43 during the rotation of the spindle 40.
[0064] First of all it should be observed that the spindle
40 is the shaft of a main motor
46 belonging to the power means
9 and, as can be observed, is supported by the frame
2.
[0065] The rotary head
41 substantially comprises a cylindrical body
47 provided with the cam means
45 and a central through hole
48 which houses the spindle
40 with which it creates the fixed connection.
[0066] Each one of the cam means
45 is constituted by a shaped channel
49 with curved profile converging towards the inside of the cylindrical body
47 of the rotary head
41.
[0067] As regards the rotary counter-head
42, it can be observed that it also consists of a substantially cylindrical body
50 comprising: the above mentioned pair of pliers
43, means
38 for thrusting the rotation levers 37 and a central through hole
51 which houses the end
40a of the spindle
40 with which it creates an idle connection.
[0068] As regards the pliers
43, they comprise two opposing jaws
52, in each one of which it is possible to identify:
- an intermediate body 53 hinged to a radial slot 54 made in the body 50 of the rotary counter-head 42;
- a first shaped projection 55 facing towards the turns S of wound wire F;
- a second shaped projection 56 facing towards the rotary head 41 to cooperate with the cam means 45 of the rotary head 41 itself.
[0069] It can also be observed that the second shaped projection
56 comprises a spherical profile
56a that is inserted in the corresponding shaped channel
49 of the cam means
45.
[0070] As already said, elastic means
44 are interposed between the rotary head
41 and the rotary counter-head
42, said elastic means comprising a spring
44a, preferably but not necessarily of the helical type, which is included between a first
housing
41a obtained in the rotary head
41 and a second housing
42a obtained in the rotary counter-head
42; wherein said housings face each other in such a way as to contain the helical spring
44a.
[0071] The thrust means
38 are constituted by a projecting body
38a present at the periphery of the substantially cylindrical body
50 of the rotary counter-head
42 that, during the rotation of the rotary counter-head, thrusts against a truncated
cone-shaped head
38b associated with the rotation levers
37.
[0072] Thus, it is clear that in the winding means
7 the opening and closing of the pliers
43 are carried out by kinematic mechanisms that are simple to construct and reliable
to operate, unlike the winding means present in the tying tools carried out according
to the known art.
[0073] As regards the main motor
46 and the auxiliary motor
19, both belong to the power means
9 respectively of the winding means
7 and of the feed unit
5 and cooperate with control means
10. These comprise an electronic programming and control unit
10a, electrically connected to both motors, and push-button means
10b provided on the tool to be used by the operator.
[0074] The electronic programming and control means
10a in turn comprise adjustable timer means that are at the disposal of the operator
and allow him/her to vary the operating time of the above mentioned motors at his/her
discretion.
[0075] The latter, in particular, can be of the alternate current or continuous current
type and can be powered through the power mains or a battery.
[0076] Figures 1 and 2 show that, above the wire bending means
6 and before the winding means 7, there is a unit
62 suited to position the bars
Ba, Bb to be tied, which serves to define their position so that their crossing point, where
they are tied, is substantially at the centre of the turns
S.
[0077] For this purpose, the positioning unit
62 comprises an upper plate
63 fixed to the frame
2, which supports a fork
64 provided with elastic adjusting means
65.
[0078] The elastic adjusting means
65 comprise a sleeve
66 fixed to the upper plate
63, inside which a pin
67 is fitted, said pin being connected to the fork
64 and said fork having a spring
68 positioned coaxially outside the pin
67 between the fork
64 and the sleeve
66.
[0079] On the opposite side of the sleeve
66 there is a screw
69 that is fitted into a hole
70 made in the pin
67.
[0080] By adjusting the screw
69, it is possible to move the pin
67 in the sleeve
66 and thus to modify the position of the fork
64 so that the latter defines the position of the bars
Ba, Bb to be tied with respect to the winding means
7.
[0081] All the parts that make up the tool, and in particular those in contact with the
wire, are not carried out with special shapes and tolerances, but according to the
common knowledge regarding mechanical construction.
[0082] Therefore, the tool that is the subject of the invention can use common wire of any
type available on the market.
[0083] In practice, the operator couples the reel
4 with the wire
F to the pin
11 and then inserts the wire F in the tubular wire-guiding element
20 belonging to the feed unit
5.
[0084] The operator uses the adjustable timer means of the electronic programming and control
unit
10a to adjust the unwinding time of the wire
F from the reel
4 and thus its length and the number of turns
S, and also the number of revolutions of the winding means
7.
[0085] Consequently, the operator sets the above mentioned parameters to adjust the clamping
force of the turns
S around the metal bars
Ba, Bb.
[0086] The bars are then positioned in such a way as to rest against the fork
64 of the positioning unit
62, after adjusting the latter through the screw
69, so that the bars are arranged substantially at the centre of the turns
S.
[0087] When the push-button means
10b are operated, the electronic unit
10 activates a programmed operating cycle that includes the following steps, performed
through the rotation of the respective electric motors:
- winding of one or more turns S of wire F around the bars Ba, Bb as shown in Figure 1 and in Figure 3;
- cutting of the wire F immediately after the winding means 7 have started rotating to move the cutting blade 30 as shown in Figure 4;
- several revolutions of the winding means 7, intended to obtain the twisting of the turns S that can be observed in Figures 11, 12 and the tying of the bars as shown in Figure
13;
- stop of the winding means 7;
- opening of the pliers 43 and separation of the tool from the tying point, as shown in Figure 12, so as to
tie the bars as shown in Figure 14.
[0088] With reference to Figures from 8 to 13, it is important to notice that the bar tying
cycle is carried out in successive steps, starting from the initial situation shown
in Figure 8, where the pliers
43 are open, with the turns
S arranged between the jaws
52 and the rotary head
41 and the rotary counter-head
42 at rest.
[0089] The rotation of the rotary head
41 takes place in the counterclockwise direction indicated by the arrow
A in Figure 9, where it is possible to observe that at the beginning of the rotation
the spring
44a is compressed and at the same time the pliers
43 are closed owing to the contact of the spherical profiles
56a of the jaws
52 with the corresponding shaped channels
49 of the cam means
45. The rotary counter-head
42 is set rotating by the rotary head
41 as shown in Figure 10 and this causes the turns
S to be twisted around the bars
Ba, Bb at the point of intersection of the latter.
[0090] Starting from the beginning of the rotation and with reference to Figures 8 and 9,
it can be observed that the projecting body
38a that makes up the thrust means
38 of the rotary counter-head
42 is arranged downstream of the truncated cone-shaped head
38b associated with the rotation levers
37 which operate the blade
30 that cuts the wire
F.
[0091] During the rotation which, has already said, takes place in the counterclockwise
direction indicated by the arrow
A, the projecting body
38a moves away from the truncated cone-shaped head
38b as shown in Figure 10, and, approximately at the end of the first revolution, reaches
a position upstream of said head, as shown in Figure 11.
[0092] As it keeps rotating, the projecting body
38a counteracts the truncated cone-shaped head
38b and moves it in the direction indicated by the arrow
C in Figures 11 and 12, in such a way as to operate the shifting kinematic means
31 and the cutting blade
30 connected to them, in order to cut the wire
F.
[0093] The turns
S are thus free starting from the cutting point at the level of the wire bending means.
[0094] As soon as the projecting body
38a has passed beyond the truncated cone-shaped head
38b, this immediately returns to the initial position due to the elastic recovery of the
spring
39a associated with the rotation levers
37, which had been compressed during the shift of the latter induced by the movement
of the truncated cone-shaped head
38b.
[0095] The rotation of the rotary head
41 and of the rotary counter-head
42 continues until the turns have been completely wound around the bars, as shown in
Figure 13.
[0096] The rotation of the rotary head
41 stops once the set time has elapsed and at this point the rotary counter-head
42 starts counter-rotating with respect to the rotary head
41 in the clockwise direction indicated by the arrow
O, due to the elastic recovery of the spring
44a, and at the same time the pliers
43 open due to the contact of the spherical profiles
56a of the jaws
52 with the cam means
45.
[0097] It can thus be understood that each revolution of the winding means
7 involves a shift of the cutting blade
30, but this does not affect the wire cutting operation, which is carried out in a single
step with the first movement of the blade itself.
[0098] At the end of the cycle the tool is ready to carry out a new tying operation, repeating
all the steps described above.
[0099] A construction variant of the tying tool that is the subject of the invention, indicated
as a whole by
200, can be seen in longitudinal section in Figure 15 and also in Figures from 16 to 19,
which show some details of the same in front axonometric view.
[0100] In said construction variant, like in the embodiment described above, the tool
200 comprises a frame
202 with a handgrip
203, which supports a reel
204 around which the metal wire
F for tying the bars
Ba, Bb is wound.
[0101] A feed unit
205 unwinds the metal wire
F from the reel
204 and makes it advance towards wire bending means
206 that are visible in their entirety in Figures 16 and 17 and that shape it to form
one or more turns
S around said bars.
[0102] At the same time the turns
S are also arranged between winding means
207 and around said bars
Ba, Bb at the level of their crossing point.
[0103] It is also possible to notice the presence of a unit
208 for cutting the metal wire F, positioned at the level of the wire bending means
206.
[0104] Power means, indicated as a whole by
209, suited to power the winding means
207 and the feed unit
205, cooperate with control means indicated by
210.
[0105] The reel
204, around which the metal wire
F is wound, is supported by a pin
211 that is fixed to and projects from the frame
202, said reel being free to rotate with respect to said pin according to the axis
X defined by the pin
211 itself.
[0106] The feed unit
205 of the metal wire
F is positioned immediately downstream of the reet
204, as shown in Figure 15, and comprises a pair of gear wheels
212, 213 that mesh with each other and between which the wire
F is included.
[0107] Figure 15a shows that both the gear wheels
212, 213 are provided with a circumferential groove
214 containing the metal wire
F, whose profile, in cross section, can be conjugated with the profile of the metal
wire itself.
[0108] The gear wheels
212, 213 cooperate with a reduction kinematic mechanism, indicated as a whole by
215, that can be observed in Figure 17 and that sets them rotating.
[0109] It comprises a bevel gear
218 that sets rotating an intermediate shaft
217, passing through the frame
202, whose end is coupled with the gear wheel
212, as shown in Figure 15.
[0110] As shown in Figure 17, the bevel gear
218 is positioned on the opposite side of the gear wheel
212 and is connected to an auxiliary motor
219 belonging to the above mentioned power means
209.
[0111] Downstream of the pair of gear wheels
212, 213 there is a tubular element
220 for guiding and controlling the wire
F while it advances.
[0112] The engaging and disengaging means
221 for the gear wheels
212, 213 are provided with a lever
222 hinged to the central part of the frame
202 through a pin
223, which supports at one end
222a the pin of the gear wheel
213 and whose opposite end
222b counteracts a cam element
224 provided with a manoeuvring rod
225 and cooperating with elastic means
226 fixed to the frame
202.
[0113] As regards the wire bending means
206, it can be observed in particular in Figures from 16 to 19 that they comprise a wire
bending channel
227 positioned downstream of the feed unit
205, beside a wire bending jaw
228.
[0114] The wire bending channel
227 is positioned downstream of the feed unit
205 and is created in a wire bending plate
229 associated with the frame
202, to which the wire bending jaw
228 is fixed, against and .above the wire bending channel
227.
[0115] The construction variant described herein is differentiated from the others due to
the fact that in opposite position above the wire bending jaw
228 and the wire bending channel
227 there is a wire bending counter-jaw
233 that, as shown in particular in Figure 15, has one end
233b hinged to the frame
202 through a pin
234 and is associated with manoeuvring means
236 that can be operated by the operator and are suited to make it rotate around the
pin
234.
[0116] The manoeuvring means
236 comprise a flexible cable
237 having one end
237a connected to a manoeuvring lever
238 associated with the frame
202 and the opposite end
237b connected to the counter-jaw
233 through a lever
237c.
[0117] A sheath
239 covers the flexible cable
237 and an elastic element
235 is interposed between the counter-jaw
233 and the frame
202 for the spontaneous return of the counter-jaw
233 to the initial position when the manoeuvring lever
238 is released.
[0118] The jaw
228 and the counter-jaw
233 present curved profiles with opposing concavities
228a and
233a, suited to receive the wire
F coming out of the wire bending channel
227 and to shape it to form one or more of the above mentioned turns
S.
[0119] It is clear, therefore, that in the construction variant described herein the wire
bending means
206, comprising the wire bending channel
227 and also the wire bending counter-jaw
233, guarantee better control and higher bending capacity of the wire, thus further reducing
the risk of the wire getting entangled during use of the tool.
[0120] Increased reliability of the tool is thus obtained.
[0121] The cutting unit
208 belongs to the wire bending plate
229 and comprises a cutting blade
230 slidingly fitted in a blade holding channel
232 that intersects the wire bending channels
227 and is operatively connected to a thrust cam
231 belonging to the winding means
207 that will be described below.
[0122] The cutting blade
230 also has, at one end, a cutting profile
230a and at the opposite end a shaped profile
230b that cooperates with the thrust cam
231 belonging to the winding means
207.
[0123] The cutting blade
230 also has a projection
230c that counteracts an elastic element
270 having one end
270a in contact with the projection
230c and the opposite end
270b fixed to the frame
202.
[0124] In this way the return of the cutting blade
230 to its position after cutting the wire
F at the end of the thrust action of the thrust cam
231 takes place spontaneously.
[0125] This construction variant of the cutting unit
208 is simpler than the embodiment described above.
[0126] This further facilitates the cutting of the wire and the operation of the tool is
more reliable owing to the reduced number of components of the kinematic mechanisms
that set the cutting blade
230 in motion.
[0127] Furthermore, the direct and axial contact between the cutting blade
230 and the thrust cam
231 favours the cutting operation, since it optimizes the axial thrust exerted by the
cam
231 on the cutting blade
230 during the rotation of the winding means
207.
[0128] The winding means
207 are visible in particular in Figures from 15 to 21, where it can be observed that,
as in the embodiment described above, they comprise:
- a spindle 240 belonging to the power means 209;
- a rotary head 241 fixed to the spindle 240;
- a rotary counter-head 242 idly connected to the end 240a of the spindle 240 and axially opposing the rotary head 241;
- a pair of pliers 243 associated with the rotary counter-head 242 and suited to house the turns S of wound wire F;
- elastic means 244 interposed between the rotary head 241 and the rotary counter-head 242;
- cam means 245 present in the rotary head 241 for opening and closing the pliers 243 during the rotation of the spindle 240.
[0129] Also in this construction variant the spindle
240 is the shaft of a main motor
246 belonging to the power means
209 and, as can be observed, is supported by the frame
202.
[0130] With particular reference to Figures 20 and 21, it is possible to observe that the
rotary head
241 substantially comprises a cylindrical body
247 provided with the cam means
245 and a central through hole
248 which houses the spindle
240 with which it creates the fixed connection.
[0131] Each one of the cam means
245 is constituted by a shaped channel
249 with curved profile converging towards the inside of the cylindrical body
247 of the rotary head
241. As regards the rotary counter-head
242, it also comprises a substantially cylindrical body
250 where there are: the above mentioned pliers
243, the thrust cam
231 of the cutting blade
230 and a central through hole
251 which houses the end
240a of the spindle
240 with which it creates an idle connection.
[0132] As regards the pliers
243, they comprise two opposing jaws
252, in each one of which it is possible to identify:
- an intermediate body 253 hinged to a radial slot 254 made in the body 250 of the rotary counter-head 242;
- a first shaped projection 255 facing towards the turns S of wound wire F;
- a second shaped projection 256 facing towards the rotary head 241 to cooperate with the cam means 245 of the rotary head 241 itself.
[0133] It can also be observed that the second shaped projection
256 comprises a spherical profile
256a that is inserted in the corresponding shaped channel
249 of the cam means
245.
[0134] As already said, elastic means
244 are interposed between the rotary head
241 and the rotary counter-head
242, said elastic means comprising as spring
244a, preferably but not necessarily of the helical type, which is included between a
first housing
241a obtained in the rotary head
241 and a second housing
242a obtained in the rotary counter-head
242, which face each other in such a way as to contain the helical spring
244a.
[0135] As regards the thrust cam
231, it is positioned at the periphery of the substantially cylindrical body
250 of the rotary counter-head
242 that, during the rotation of the rotary counter-head, thrusts against a shaped profile
230b present at one end of the cutting blade
230.
[0136] As regards the main motor
246 and the auxiliary motor
219, both belong to the power means
209 respectively of the winding means
207 and of the feed unit
205, and cooperate with control means
210.
[0137] These comprise an electronic programming and control unit
210a, electrically connected to both motors, and push-button means
210b provided on the tool to be used by the operator.
[0138] The electronic programming and control means
210a in turn comprise adjustable timer means that are at the disposal of the operator
and allow him/her to vary the operating time of the above mentioned motors at his/her
discretion.
[0139] The motors, in particular, can be of the alternate current or continuous current
type and can be powered through the power mains or a battery.
[0140] In practice, when the operator wants to use the tool, first of all he/she couples
a reel
204 of wire
F with the pin
11 and inserts the wire
F in the tubular wire-guiding element
220 belonging to the feed unit
205.
[0141] The operator uses the adjustable timer means of the electronic programming and control
unit
210a to adjust the unwinding time of the wire
F from the reel
204 and thus its length as well as the number of turns S and the number of revolutions
of the winding means
207.
[0142] Consequently, the operator sets the number of revolutions to adjust the clamping
force of the turns
S around the metal bars
Ba, Bb.
[0143] The bars
Ba, Bb are arranged between the wire bending jaw
228 and the wire bending counter-jaw
233 and then the operator activates a programmed operation cycle via the push-button
means
210b of the electronic unit
210.
[0144] This includes the following steps, which are performed by operating the respective
electric motors:
- winding of one or more turns S of wire F around the bars Ba, Bb as shown in Figure 15 and in Figure 17;
- cutting of the wire F immediately after the winding means 207 have started rotating to move the cutting blade 230 as shown in Figure 18;
- several revolutions of the winding means 207, intended to obtain the twisting of the turns S that can be observed in Figures 25, 26 and the tying of the bars as shown in Figure
27;
- stop of the winding means 207;
- opening of the pliers 243 and separation of the tool from the tying point, as shown in Figure 26, so as to
tie the bars as shown in Figure 28.
[0145] With reference to Figures from 22 to 27, it is important to notice that the bar tying
cycle is carried out in successive steps, starting from the initial situation shown
in Figure 22, where the pliers
243 are open, with the turns
S arranged between the jaws
252 and the rotary head
241 as well as the rotary counter-head
242 at rest.
[0146] The rotation of the rotary head
241 takes place in the counterclockwise direction indicated by the arrow
A in Figure 23, where it is possible to observe that at the beginning of the rotation
the spring
244a is compressed and at the same time the pliers
243 are closed owing to the contact of the spherical profiles
256a of the jaws
252 in the corresponding shaped channels
249 of the cam means
245.
[0147] The rotary counter-head
242 is set rotating by the rotary head
241 as shown in Figure 24 and this causes the turns
S to be twisted around the bars
Ba, Bb at their point of intersection.
[0148] Starting from the beginning of the rotation and with reference to Figures 22 and
23, it can be observed that the thrust cam
231 is positioned downstream of the shaped profile
230b positioned at the end of the cutting blade
230 that therefore for the moment is not operated.
[0149] During the rotation of the head which, as shown in Fgure 23, takes place in the counterclockwise
direction indicated by the arrow
A, the thrust cam
231 moves away from the shaped profile
230b until it comes into contact with the same, approximately towards the end of the first
revolution, as shown in Figure 25.
[0150] While it keeps rotating, the thrust cam
231 counteracts the shaped profile
230b and moves the cutting blade
230 in the direction indicated by the arrow
C of Figure 25, in order to cut the wire
F.
[0151] The turns S are thus free, starting from the cutting point at the level of the wire
bending means.
[0152] As soon as the thrust cam
231 has passed beyond the shaped profile
230b, the cutting blade
230 immediately returns to its initial position due to the action of the elastic element
270 that recalls it.
[0153] The rotation of the rotary head
241 and of the rotary counter-head
242 continues until the turns have been completely wound around the bars, as shown in
Figure 27.
[0154] The rotation of the rotary head
241 stops once the set time has elapsed and at this point the rotary counter-head
242 starts counter-rotating with respect to the rotary head
241 in the clockwise direction indicated by the arrow
O, due to the elastic recovery of the spring
244a, and at the same time the pliers
243 open due to the contact of the spherical profiles
256a of the jaws
252 with the cam means
245. It can thus be understood that each revolution of the winding means
207 involves a shift of the cutting blade
230, but this does not affect the wire cutting operation, which is carried out in a single
step with the first movement of the blade itself.
[0155] At the end of the cycle, the tool is ready to carry out a new tying operation, repeating
all the steps described above.
[0156] It is important to point out that in both the construction variants described above
all the parts that make up the tool and in particular those in contact with the wire
are not carried out with special shapes and tolerances, but according to the common
knowledge regarding mechanical construction.
[0157] Therefore, the tool that is the subject of the invention, in both construction variants,
can use common wire of any type available on the market.
[0158] On the basis of the above, it is clear that the tool that is the subject of the invention,
in both the construction variants described, achieves all the set objects.
[0159] In particular, the tool is simpler to construct than the known tools, especially
as regards the means for winding the metal wire around the bars.
[0160] Also the kinematic elements of the moving parts that make up the tool are simpler
to construct.
[0161] Furthermore, the wire bending means and the wire cutting unit are more reliable than
those present in tying tools of known type.
[0162] In the construction phase, further construction variants can be made, which are neither
represented nor described herein, but which must all be considered protected by the
preset patent if they fall within the scope of the following claims.
[0163] In the cases where the technical characteristics illustrated in the claims are followed
by references, these have been added only with the aim to facilitate the comprehension
of the claims themselves and therefore said references do not have any limiting effect
on the degree of protection to be granted to each element they identify only by way
of example.
1. Werkzeug (1; 200) zum Zusammenbinden von Stäben (Ba, Bb), insbesondere Eisenstangen
für bewehrten Beton, umfassend einen Rahmen (2; 202), dem die folgenden Elemente zugeordnet
sind:
- ein Handgriff (3; 203);
- eine Spule (4; 204), auf der der Metalldraht (F) zum Zusammenbinden der Stäbe (Ba,
Bb) aufgewickelt ist;
- eine Vorschubeinheit (5; 205) zum Abwickeln der Spule (4; 204) und Vorschieben des
Metalldrahts (F);
- Drahtbiegemittel (6; 206), die dazu geeignet sind, den aus der Vorschubeinheit (5;
205) heraustretenden Draht (F) zu formen, um eine oder mehrere Windungen (S) um die
Stäbe (Ba, Bb), die zwischen den Drahtbiegemitteln (6; 206) angeordnet sind, herum
zu bilden;
- Mittel (7; 207) zum Wickeln der Windungen (S) um die Stäbe (Ba, Bb) herum;
- mindestens eine Zange (43; 243), die dazu geeignet ist, die Windungen (S) aufzunehmen;
- eine Einheit (8; 208) zum Schneiden des Metalldrahts (F);
- Mittel (9; 209) zum Antreiben der Wickelmittel (7; 207) und der Vorschubeinheit
(5; 205);
- eine Spindel (40; 240), die zu den Antriebsmitteln (9; 209) gehört;
- Steuermittel (10; 210) für die Antriebsmittel (9; 209);
dadurch gekennzeichnet, dass die Wickelmittel (7; 207) Folgendes umfassen:
- einen Drehkopf (41; 241), der an der Spindel (40; 240) angebracht ist;
- einen Dreh-Gegenkopf (42; 242), der freilaufend mit dem Ende (40a; 240a) der Spindel
(40; 240) axial gegenüber dem Drehkopf (41; 241) verbunden ist, wobei die mindestens
eine Zange (43; 243) dem Dreh-Gegenkopf zugeordnet ist;
- elastische Mittel (44; 244), die zwischen dem Drehkopf (41; 241) und dem Dreh-Gegenkopf
(42; 242) angeordnet sind; und
- Nockenmittel (45; 245), die im Drehkopf (41; 241) vorhanden sind, zum Öffnen und
Schließen der Zange (43; 243) während der Drehung der Spindel (40; 240).
2. Werkzeug (1; 200) nach Anspruch 1), dadurch gekennzeichnet, dass die Spindel (40; 240) die Drehwelle eines Hauptmotors (46; 246) ist, der zu den Antriebsmitteln
(9; 209) gehört.
3. Werkzeug (1; 200) nach Anspruch 1), dadurch gekennzeichnet, dass der Drehkopf (41; 241) einen im Wesentlichen zylindrischen Körper (47; 247) umfasst,
der mit den Nockenmitteln (45; 245) sowie mit einem zentralen Durchgangsloch (48;
248) ausgestattet ist, das die Spindel (40; 240) aufnimmt mit der es eine feste Verbindung
bildet.
4. Werkzeug (1; 200) nach Anspruch 1), dadurch gekennzeichnet, dass der Dreh-Gegenkopf (42; 242) einen im Wesentlichen zylindrischen Körper (50; 250)
umfasst, der mit mindestens einer Zange (43; 243) sowie mit einem zentralen Durchgangsloch
(51; 251) ausgestattet ist, das das Ende (40a; 240a) der Spindel (40; 240) aufnimmt
mit dem es eine freilaufende Verbindung bildet.
5. Werkzeug (1; 200) nach Anspruch 1),
dadurch gekennzeichnet, dass die mindestens eine Zange (43; 243) mindestens zwei Backen (52; 252) umfasst, die
einander gegenüberliegen und jeweils Folgendes umfassen:
- einen Zwischenkörper (53; 253), der an einem radialen Schlitz (54; 254), der im
zylindrischen Körper (50; 250) des Dreh-Gegenkopfs (42; 242) ausgebildet ist, schwenkbar
angebracht ist;
- einen ersten Formvorsprung (55; 255), der zu den Windungen (S) hin weist;
- einen zweiten Formvorsprung (56; 256), der zum Drehkopf (41; 241) hin weist, um
mit den Nockenmitteln (45; 245) des Drehkopfs (41; 241) zusammenzuwirken.
6. Werkzeug (1; 200) nach Anspruch 5), dadurch gekennzeichnet, dass der zweite Formvorsprung (56; 256) ein kugelförmiges Profil (56a; 256a) umfasst,
das mit den Nockenmitteln (45; 245) zusammenwirkt.
7. Werkzeug (1; 200) nach einem der Ansprüche 1), 3), 5) oder 6), dadurch gekennzeichnet, dass jedes der Nockenmittel (45; 245) ein Formkanal (49; 249) mit bogenförmigem Profil
ist, der zum Inneren des zylindrischen Körpers (47; 247) des Drehkopfs (41; 241) hin
konvergiert.
8. Werkzeug (1; 200) nach Anspruch 1), dadurch gekennzeichnet, dass die elastischen Mittel (44; 244) eine Feder (44a; 244a) umfassen, die zwischen einem
ersten, im Drehkopf (41; 241) ausgebildeten Gehäuse (41a; 241a) und einem zweiten,
im Dreh-Gegenkopf (42; 242) ausgebildeten Gehäuse (42a; 242a), die zueinander hin
weisen, enthalten ist.
9. Werkzeug (1) nach Anspruch 1),
dadurch gekennzeichnet, dass die Drahtbiegemittel (6) Folgendes umfassen:
- einen Drahtbiegekanal (27), der stromabwärts der Vorschubeinheit (5) angeordnet
ist und in einer Drahtbiegeplatte (29) ausgebildet ist, die zum Rahmen (2) gehört
und der die Schneideeinheit (8) für den Draht (F) zugeordnet ist;
- eine Drahtbiegebacke (28), die neben dem Drahtbiegekanal (27) angeordnet ist, gegen
die Drahtbiegeplatte (29) angebracht ist und dazu geeignet ist, den aus dem Drahtbiegekanal
(27) heraustretenden Draht (F) aufzunehmen und zu einer oder mehreren Windungen (S)
zu formen.
10. Werkzeug (1) nach Anspruch 9), dadurch gekennzeichnet, dass die Schneideeinheit (8) eine Schneideklinge (30) umfasst, die mechanisch mit kinematischen
Verschiebungsmittein (31) verbunden ist und gleitend in einem Klingenhaltekanal (32)
eingepasst ist, der den Drahtbiegekanal (27) kreuzt und in der Drahtbiegeplatte (29)
ausgebildet ist.
11. Werkzeug (1) nach Anspruch 10), dadurch gekennzeichnet, dass die Schneideklinge (30) an einem Ende mit einer Zahnstange (33), die mit den kinematischen
Verschiebungsmitteln (31) gekoppelt ist, und an einer mittleren Stelle mit einer Ausnehmung
(34) ausgestattet ist, die eine geneigte Schnittkante (35) definiert, die den zu schneidenden
Draht (F) aufnimmt, der aus dem Drahtbiegekanal (27) heraustritt.
12. Werkzeug (1) nach Anspruch 11), dadurch gekennzeichnet, dass die kinematischen Verschiebungsmittel (31) ein Zahnrad (36) umfassen, das in die
Zahnstange (33) der Schneideklinge (30) eingreift und mit Drehhebeln (37) verbunden
ist, die mit Schubmitteln (38) zusammenwirken, die dem Dreh-Gegenkopf (42) zugeordnet
sind.
13. Werkzeug (1) nach Anspruch 1), dadurch gekennzeichnet, dass die Vorschubeinheit (5) mindestens ein Paar aus Zahnrädern (12, 13) umfasst, die
ineinander eingreifen, zwischen denen der Draht (F) vorhanden ist und die mit einem
kinematischen Reduktionsmechanismus (15) zum Drehen der Zahnräder (12, 13) und zum
Vorschieben des Drahts (F) zwischen diesen zusammenwirken.
14. Werkzeug (1) nach Anspruch 1), dadurch gekennzeichnet, dass die Antriebsmittel (9) einen Hauptmotor (46), der den Wickelmitteln (7) zugeordnet
ist, und einen Hilfsmotor (19), der der Vorschubeinheit (5) zugeordnet ist, umfassen,
wobei beide Motoren (46, 19) elektrisch mit den Steuermitteln (10) verbunden sind.
15. Werkzeug (200) nach Anspruch 1),
dadurch gekennzeichnet, dass die Drahtbiegemittel (206) Folgendes umfassen:
- einen Drahtbiegekanal (227), der in einer Drahtbiegeplatte (229) ausgebildet ist,
die zum Rahmen (202) gehört und der die Schneideeinheit (208) zugeordnet ist;
- eine Drahtbiegebacke (228), die neben dem Drahtbiegekanal (227) gegen die Drahtbiegeplatte
(229) angebracht ist;
- eine Drahtbiege-Gegenbacke (233), die der Drahtbiegebacke (228) und dem Drahtbiegekanal
(227) gegenüberliegt,
wobei die Backe (228) und die Gegenbacke (233) dazu geeignet sind, den aus dem Drahtbiegekanal
(227) heraustretenden Draht (F) derart zu formen, dass eine oder mehrere Windungen
(S) gebildet werden.