The invention relates to a binding machine comprising a twisting assembly and a binding hook, wherein the twisting assembly comprises a power unit driven by auxiliary power, such as electricity, pressurized medium or the like, the rotational movement of the same being transmitted to the binding hook for binding by means of a binding organ, such as a wire or the like, by a rotational movement around the longitudinal axis of the binding hook, wherein the twisting assembly comprises also a control device for controlling the operation of the binding machine, provided with at least a control organ, such as a current switch or the like for turning the power unit on and off. The binding machine is particularly intended for use in binding structural steel rods for reinforcement of concrete by a wire or the like.

Conventional techniques used at least in Finland, by which steels of reinforced concrete are bound together, include welded nets of serial production, concrete pile bindings made by robots and conventional reinfor¬ cements bound by wires. A welded binding has the problem that the welding melts part of the steel bar, wherein the whole cross-sectional area of..the struc¬ tural steel cannot be utilized in designing the structure. Also, it is not advantageous to use welding under difficult, changeable conditions or at sites with a small overall size.

In practice, structural steel rods are primarily bound to each other by a wire or wire loop binding which is tightened by twisting performed by a manual tool. The tool generally used is a reinforcing hook comprising a handle with a rotating hook or the like carried in bearings. In Southern Europe, the manual tool in general use is pliers. Such manual techniques

are still used in rein orcement units of even modern concrete factories, in which automation is utilized in steel rod cutting and wire loop forming. Of the working time of people doing manual reinforcing work, 30 to 70 % is spent on steel rod binding work, and this is even more significant at reinforcement units with rationalized production. Manual binding work is a stress on e.g. the joints, tendons and muscles of hand, because of the restricted, monotonous motions and the ergono ically inadvantageous working position.

For machine binding, a machine-powered binding device for reinforcing work is presented in the publication EP-234569. The binding device comprises a magazine supported by the body of the operator and a hand-held tool. The magazine contains e.g. a power supply battery and an electric motor, which are connected by a flexible shaft contained in a sleeve to the hand-held tool whose rotatable end part actually forms the working device that performs the binding. The magazine may also be used to contain a wire coil, in which case it is advantageous to arrange the wire to be conveyed by the said sleeve to the hand-held tool of the binding device. In the publication, two different embodiments are presented of the hand-held tool of the binding device. In the first embodiment, the rotatable tool comprises an arrangement similar to pliers, the operation being based on the utilization of continuous wire uncoiled from the magazine. In the second embodiment, the tool comprises a hook which is used for twisting wire bindings provided with loops at the ends.

The solution presented in the above-mentioned publica- tion is certainly a step in the right direction, because it is based on the use of secondary power for performing the torsional movements stressing the joints. Nevertheless, the solution according to the

publication has not succeeded in convincing a majority of users, at least in Finland, because of its very difficult use. First, this is due to the fact that the motor of the binding device is placed in a magazine supported e.g. on the shoulder, in which case the magazine swinging freely on the waist is, particularly under difficult circumstances, also subject to damage. Moreover, the design of the hand-held tool of the binding device does not take into account ergonomical aspects; because the working device and the handle are substantially in the same axial direction, the most advantageous position of the wrist and/or the arm for performing the work is not possible.

Consequently, the solution according to the description above, as well as other binding techniques of prior art, do not offer a solution with a simple construction and satisfactory performance from both ergonomic and usability points of view.

It is the aim with the binding machine according to the present invention to provide a significant improvement to the drawbacks described above and thus to raise the level of prior art. For achieving this aim, the binding machine comprises an integrated body compris¬ ing- at least a power unit, such as a motor or the like, a fixing device, such as a socket or the like, preferably detachably attached to the power organ and provided with a binding hook, at least when in use, and a control device comprising, in addition to a current switch, an organ effecting on the basis of the reciprocal force between the binding hook and the body to the functioning of the binding machine, preferably with adjustable sensitivity, such as a moment switch or the like.

The most important advantages of the binding machine according to the invention include both the construe-

tion of the binding machine and the simplicity and reliability of its use, which are central requirements for developing a good installation technique. The compact structure of the binding machine according to the invention enables its use in a variety of condi¬ tions and environments. Also, it provides an ergonom- ically ideal construction, preventing stress injuries due to the recurrence of an operation. Further, it enables ideal binding so that a too loose or too tight binding is avoided. Thus, for using the binding machine according to the invention, the person doing the reinforcing work does not need to have the skill required by the techniques presently used, because the machine goes off at a certain moment. Moreover, with respect to the operating costs, using the binding machine according to the present invention is more inexpensive than the present solutions, because the binding work can be done clearly faster than with the present techniques.

Advantageous embodiments of the binding machine according to the invention are presented in other dependent claims for the binding machine.

In the following description, the invention is il¬ lustrated in detail with reference to the appended drawings, in which

Fig. 1 shows an overall view of binding opera- tion using a binding machine according to the invention.

Fig. 2 shows in principle a side view of the bindingmachine accordingto the invention.

Fig. 3 shows a cross-sectional view in longitudi¬ nal direction of a detail of the socket and the binding hook fixed into it,

Fig. 3a shows a cross-sectional view in line A-A of Fig. 3, and

Fig. 4 shows a cross-sectional view in longitudi¬ nal direction of a detail of the indexing means connected to the moment switch.

The invention relates to a binding machine comprising a twisting assembly 1 and a binding hook 2. The binding machine is intended particularly for binding together structural steel rods for reinforcement of concrete. The twisting assembly 1 comprises of a power unit 3, the rotational movement of which being transmitted to the binding hook 2 for binding by means of a wire bond or the like, by a rotational movement w around the longitudinal axis of the binding hook 2. The twisting assembly 1 comprises also a control device 5 for controlling the operation of the binding machine, provided with at least a current switch 5a. According to the invention, the binding machine comprises an integrated body 6 which is composed of at least one power unit 3, such as a motor, a fixing device 4 attached to the power unit 3, such as a socket, in which the binding hook 2 is fixed either as a solid or a detachable piece, and of the control- device 5 provided with a moment switch 5b in addition to the current switch 5a.

According to Figs, l and 2, the body 6 comprises a handle 6a designed to fit and to protect hand. The longitudinal direction K of the handle 6a is substan¬ tially at an angle differing from the longitudinal direction S of the binding hook. In the presented embodiment, the current switch 5a of the control device 5 is placed in the handle 6a, most advantageous¬ ly to be operated by the index finger. The binding machine is also provided with a conventional on/off

switch 5d maintaining the operation of the machine irrespective of the position of the current switch 5a. For optimal performance, the binding machine comprises an adjustable moment switch 5b for obtaining the necessary tightness of the wire bond on basis of the reciprocal force between the binding hook 2 and the body 6.

In the embodiments shown in Figs, l and 2, the power unit is most advantageously an electric motor 3 with adjustable speed and direction of rotation, wherein the twisting assembly 1 comprises a rechargeable bat¬ tery 8. In an advantageous application for operations of long duration, the battery 8 is, because of its size, preferably placed e.g. to the belt, sleeve or pocket of the user, wherein the electric lead 8a connecting the battery 8 and the body 6 can be placed in connection with the working clothes so that it does not disturb the actual operation. In an advanta- geous application particularly for small operations of short duration, it is advantageous to arrange connecting organs (not shown in the drawings) in connection with the body 6, wherein batteries of low energy, sufficient for smaller operations, can be attached directly to the body 6.

In the longitudinal cross-section shown in Fig. 3, the binding hook 2 is, as an advantageous embodiment, arranged detachably to the socket 4 by a fixing arrangement 7. The socket 4 comprises a barrel-like part 4a connected to the shaft of the motor 3 and a solid locking part 4b attached thereto with a thread¬ ed coupling. The fixing arrangement 7 comprises thus the first attachment organs 7a for preventing a reciprocal rotational movement of the binding hook 2 and the socket 4 and the second attachment organs 7b for preventing a reciprocal movement of the binding hook 2 and the socket 4 in the longitudinal direc-

tion S. In the presented embodiment, the first attach¬ ment organs 7a are arranged by an angular formation of the corresponding contact surfaces of the parts of the binding hook 2 and the barrel-like part 4a of the socket 4 coming into contact with each other, and the second attachment organs 7b are arranged by forming a lug in the binding hook 2, supported to the locking part 4b of the socket 4 in the axial direction.

In an advantageous embodiment, the control device 5 comprises also a mechanically, electrically or by pressurized medium powered indexing means 5c which, in a situation of usage after binding and after detachment of the binding hook 2 from the bond, returns the binding hook 2 into an immobile standby position, wherein the tip 2a of the binding hook 2 is at a certain angular position α with respect to the co¬ ordinates of the rotational movement of the binding hook 2, as shown in Fig. 3a. This indexing means 5c is used to eliminate the problem that the binder should turn the device because of the random position of the binding hook 2 after the previous binding operation in order to find a correct position for performing the next binding operation with it.

In the longitudinal cross-section shown as an example in Fig. 4, a mechanically powered indexing means 5c is shown for returning the position of the binding hook 2. Thus, use is made of the spring-loaded moment switch 5b in a manner that there is a pin 5bn on the circle of the moment disk 5bk, which is normally freely movable on the circle of the casing. For returning the binding hook 2 back to the standby position, there is a switch 5ck at the end of the brake rod in the groove worked in the body 6 which is pushed forward, wherein the opposite end of the brake rod is pushed onto the circle of the moment disk 5bk thus stopping the rotation of the binding hook 2 into

the position determined by the pin 5bn, whereafter the moment switch 5b releases the moment disk 5bk from the counterpart disk 3k on the shaft of the motor 3. The construction described above can also, e.g. by applying electronics, be made automatically operated, wherein a separate switch 5ck is not needed. In this case, it functions e.g. by a time delay adjusted by a delay adjustment organ after stopping the function of the motor 3 or the rotation of the binding hook 2 by the current switch 5a or by the moment switch 5b. Also, the indexing means 5c can be most advantageously arranged to be adjustable so that e.g. by means of a separate angle adjustment organ, the standby position of the binding hook 2 can be adjusted according to the needs of the user or the place of use into two or more angular positions.

According to the description above, the body 6 of the binding machine can also be used to operations of different kind, because the binding hook 2 is detach¬ able from the fixing device 4. If a conventional socket formed of movable jaws is used as the fixing device 4, the body 6 can be used with suitable equip¬ ment e.g. for drilling, screwing in, unscrewing, or the like. An embodiment of this kind is, however, most advantageous in so-called everyman's use, because the weight or size of the body 6 may exceed the optimum for use of the machine in continuous binding work. Thus, in an advantageous embodiment for occupational binding work, it is possible to arrange the binding hook 2 and the fixing device 4 in an integrated structure, in which case their combination is made e.g. of one piece by casting or of two pieces substan¬ tially fixed to each other. Also in this embodiment, in case the binding hook 2 is broken or damaged, the fixing device 4, which is according to the invention detachably connected to the power unit 3 and provided with the binding hook 2, can be replaced by a new

one, in which case the whole machine does not need to be replaced.

The binding machine according to the invention is used so that a wire, provided with loops at each end, is placed around the steels to be bound, whereafter the binding hook 2 of the binding machine is inserted through both loops. Next, the motor 3 is started by pressing the current switch 5a, and the binding hook 2 fixed to the socket 4 connected thereto starts rota¬ ting w. The rotational speed of the electric motor 3 is adjusted to suit the length and strength of the wire, e.g. by a linear function of the current switch 5a, so that the highest rotational speed of the electric motor 3 is achieved by pressing it down.

The moment switch 5b is used to tighten the wire into a suitable tightness. Consequently, it is possible to perform without previous occupational experience the operation which in manual binding requires skilled finger sensitivity to prevent breaking of the wire.

It is advantageous to alter the direction of rotation of the electric motor 3, because this makes it possible to use the binding machine also for unravelling the bond already bound. It is necessary to fix the binding hook 2 and the fixing device 4 to each other for preventing their reciprocal movement in their longi¬ tudinal direction, because in practical situations, the binding hook 2 must be used to pull wire bonds to suitable locations as well as to move the steel bars to be bound for making binding possible.

After the binding operation, the binding hook 2 is removed from the bond, whereafter the positioning organ 5c returns the binding hook 2 into the immobile standby position for the next binding operation. Keeping the battery 8 separate from the body 6 has

the advantage of minimizing the weight of the body 6, which provides expedient use of the binding machine. Consequently, fixing the battery e.g. to a belt enables the use of a more effective and a slightly heavier battery. Also, this enables the use of a binding machine at reinforcement work sites where it is almost without exception impossible or very risky to use e.g. power current or pressurized air as a power source because of risks related to occupational safety or the like.

It is clear that the invention is not restricted to the embodiments presented above, but it can be modified within the basic idea even to a great extent. For example, the appearance of the binding machine may vary to a large degree, depending on the quality of the components and their technical properties, such as the supply voltage, the speed of rotation, and the like. Also, in an advantageous embodiment, it is possible to arrange the position of the handle to be adjusted e.g. by means of a locking joint arrangement or the like, in which case the body can be kept straight when it is not in use and be bended for use according to the needs of the user or the place of use. Further, there can be a variety of solutions relating to the different parts of the control device and to changing the speed and direction of rotation of the power unit, so that the binding machine can comprise e.g. a central control unit similar to a control panel.