Patent Abstract:
The arrangement for binding objects ( 6 ) by means of a band ( 5 ), the ends of which are retained by a lock ( 4 ), having a magazine for a chain ( 11 ) of interconnected locks ( 12 ), a tool ( 1 ) with a guide channel ( 14 ) for the chain ( 11 ) of locks ( 12 ), a conveying connection ( 10 ) from the magazine to the guide channel ( 14 ), a tool drive ( 29 ) and a conveying drive. The conveying drive provided according to the invention is a spring ( 33 ) which can be subjected to stressing by an electric tool drive ( 29 ). This has the advantage that a high advancement force can be produced even when a relatively low-power drive motor is used.

Full Description:
BACKGROUND OF THE INVENTION 
     It is known for objects to be bound by means of a band which is positioned as a loop around the object, the ends of said loop then being fixedly connected to one another by a lock. If a large number of binding operations are to be carried out at a workstation, as is the case, for example, in the production of cable harnesses, use is made of largely automatically operating tools which are assigned magazines for the locks and the band. Whereas small magazines may be arranged on the tool itself, large magazines are kept stationary. In order for it to be possible for the locks to be fed to the tool from such stationary magazines, the locks are designed as a more or less endless lock chain by the individual locks being retained, for example, on a carrier strip or being connected directly to one another by material crosspieces which are severed before the individual lock is used. In the case of known tools, the conveying path for the lock chain between the magazine and tool is formed by a flexible tube. If the connection between the individual locks is firm enough, it may be possible, if appropriate, to dispense with the protection given by such a flexible tube. The conveying path is then formed by the lock chain as such. In each case, considerable forces may be necessary in order to move the lock chain up into the tool if, for example, the flexible tube forming the conveying path is curved or the lock chain, before it passes into the tool, is angled in relation to the guide channel accommodating it in the tool. In the case of known tools, a pneumatic drive is provided for this purpose. This has the property of comparatively large forces being available for brief driving tasks, as occur during the brief advancement of the lock strip between two binding operations. A pneumatic drive, however, has disadvantages in comparison with an electric drive, for example in respect of the weight and the dimensions of the tool and the pressure-medium feed. It is also the case that the energy consumption and the noise development are unfavourable in pneumatic tools. Electric drives on binding tools are also known. However, if they are not likewise to be heavy and bulky, these have the disadvantage that they cannot supply high power for a brief period, which is required for moving the lock chain up into the tool. For a demonstration of the prior art, you are referred to the brochure entitled “Automatische Bündel-und Verschluβwerkzeuge [Automatic bundling and closure tools] Autotool/Tytontool” from Paul Hellermann GmbH, EP-B 303723, EP-B 565968 and U.S. Pat. No. 4,610,067. In the case of EP-A 297 337 and EP-A 565 968, the advancement is brought about by the actuation of a hand lever. 
     Taking as the departure point the prior art mentioned in the preamble of claim  1 , namely the abovedescribed brochure, the object of the invention is to make it possible to use an electric drive in the case of tool arrangements with a stationary lock magazine. The solution according to the invention resides in the features of claim  1  and preferably those of the subclaims. 
     SUMMARY OF THE INVENTION 
     Provision is accordingly made for the conveying drive provided to be a spring which can be subjected to stressing by the electric tool drive. The spring may easily be dimensioned such that it applies the necessary advancement forces. It may also be subjected to stressing by a low-torque motor, because all that this requires is suitable dimensioning of a reduction gear mechanism located between the motor and the spring. 
     Expediently provided for the purpose of subjecting the lock chain to the advancement force is an advancement engagement element which is arranged on the guide channel of the tool and is guided such that it can be moved in the direction thereof. The advancement engagement element is subjected to loading in the advancement direction exclusively by the spring during the advancement phase. In another part of the operating cycle, namely when a binding operation has been completed and a new lock has to be provided, it is connected to a restoring means which is moved counter to the advancement direction by the tool drive. Said restoring means moves the advancement engagement element back by at least the longitudinal dimension of a lock, in order that it can engage with the following lock in the subsequent advancement operation. 
     The restoring means is expediently a rotary cam, because such an element is straightforward to provide in design terms and can easily be engaged with, and disengaged from, the advancement engagement element or an interposed transmission element. Such a transmission element between the rotary cam and the advancement engagement element is designed, according to the invention, as a multi-armed lever, of which one lever arm interacts with the rotary cam, while a second lever arm is connected to the spring and a third lever arm is connected to the advancement engagement element. The arrangement may also be such that one lever arm performs a number of the functions which have just been specified. 
     In a particularly preferred embodiment, the rotary cam periodically passes into the pivoting region of the lever arm assigned to it and also leaves said pivoting region again. As soon as the rotary cam engages with the lever arm, it rotates it in such a way that the spring is subjected to stressing and the advancement engagement element is retracted. As soon as it leaves the pivoting region of the lever arm, the spring, and thus the conveying drive, is disengaged. The advancement engagement element engages with the next lock and moves the latter forwards. Since this lock is fixedly connected to the lock chain following it, the latter is likewise moved up. 
     The spring force is preferably then maintained in order for the lock located in front of the advancement engagement element, as seen in the advancement direction, or the foremost lock of the number of locks located in front of the same, to be forced into that position in which it is ready for the following binding operation and in order for it, if appropriate, also to be retained in this position. 
     According to a particular feature of the invention, which possibly merits protection independently of the features explained above, the advancement engagement element is arranged on a carriage which is guided such that it can be moved essentially parallel to the guide channel, and which is also equipped with a device for separating the locks from one another. This is based on the idea that the as yet unseparated locks located in the vicinity of the advancement engagement element are positioned very precisely in relation to the advancement engagement element, and a separating device, the position of which is fixed in relation to the advancement engagement element, can thus carry out the separating operation at a very precisely determinable location of the lock chain. This is important, in particular, in the cases in which the locks are connected to one another by very short crosspieces, which have to be cut in a correspondingly precise manner. 
    
    
     BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The invention is explained in more detail hereinbelow with reference to the drawing, which illustrates an advantageous exemplary embodiment and in which: 
     FIGS. 1 to  3  show three schematic longitudinal sections through the tool at different functional stages, and 
     FIG. 4 shows a view of the detent arrangement on the carrier. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The tool body  1 , with a handle  2 , has, on its end side, a mount (not illustrated in any more detail) for a lock  4  through which, by means which are not of any interest in this context, a band  5  is guided in the direction of the arrows, tied, in the form of a loop  7 , around an object  6  which is to be bound, and guided back into the lock  4  by way of its free end. Thereafter, the band  5  is tensioned, the protruding end is cut off and the lock  4  is released from the lock mount  3  (FIG.  3 ). 
     In order to allow largely automatic operation, the locks which are to be processed are fed automatically to the lock mount  3 . From a large stationary magazine (not illustrated), they are guided to the tool body  1  through a flexible tube  10  in the form of a lock chain  11 , in which the individual locks  12  are connected integrally to one another by crosspieces  13 . At the tool body, the lock chain  11  is accommodated by a guide channel  14 , which opens out at the lock mount  3 . 
     Provided on the guide channel  14  is a device  20  for advancing and separating the locks. The illustration of the guide channel  14  has been interrupted in the region of this device  20 . It goes without saying, however, that a guide for the lock chain  11  is also provided in this region. Parallel to said lock guide, a carriage  21 , which is illustrated in the drawing by dots, is mounted such that it can be moved in the arrow direction  22 . Two guide walls  23  indicate the carriage guide schematically. Provided for driving the carriage is a lever arm  24  which interacts with the carriage  21  in a suitable manner at  25  and can be pivoted about a pin  26  which is fixed on the tool body  1 . It is rigidly connected to a cam lever  27  which projects into the circulatory path of two cams  28 , which are arranged on a cam disc  29  which is driven in rotation about the pin  30  by an electric motor. 
     Rigidly connected to the lever arms  24 ,  27  is a third lever arm  31 , the end of which is articulated on the connecting rod  32  of a compression spring  33 . The spring  33  forces the lever arm  31  upwards (in the drawing) and thus forces the end of the lever arm  24  in the direction of the end of the tool. If, in contrast, a cam  28  engages with the cam lever  27 , as is illustrated in FIG. 3, the cam lever  27  is forced downwards. The lever arm  31  is also moved downwards at the same time, as a result of which the spring  33  is subjected to stressing. The lever arm  24  and, with it, the carriage  21  are moved to the right (in the drawing), that is to say counter to the advancement direction of the lock chain  11 . The rotary cam  28  thus forms the abovementioned restoring means for the carriage  21 . When the cam  28  has passed the cam lever  27 , the spring  33  tries to pivot the lever arrangement  24 ,  27 ,  31  in the anti-clockwise direction and thus to move the carriage  21  in the advancement direction. 
     A detent  40  is articulated, as advancement engagement element, on the carriage  21 . It is designed and arranged such that its tip is forced into engagement with the lock chain  11  by a spring which is not shown. In more general terms, the detent  40  has a surface which can engage with a rearwardly oriented surface of a lock in order to subject the latter to an advancement force. 
     Also articulated on the carriage  21  is a rocker  41 , which is forced in the arrow direction  42  by a spring which is not illustrated. The rocker bears, at its front end, a blade  43  which is intended, during movement counter to the arrow direction  42 , to sever a crosspiece  13  between successive locks  12 . In order to bring about this cutting movement of the rocker  41 , a cam lever  44  is provided, thus intercepting the rear end of the rocker  41  by way of a nose  45 . The bottom end of the cam lever projects into the circulatory path of the rotary cam  28 . If it is intercepted by a rotary cam according to FIG. 2, then the pivot lever  44  is pivoted in the clockwise direction and the rocker  41  is pivoted counter to the arrow direction  42 . The blade  43  executes the cut in the process. In the embodiment illustrated, the cam lever  44  is articulated on the carriage. Instead of this, it is also possible for it to be fitted on the tool body, as long as it is ensured that it interacts with the rocker. 
     The detent  40  is designed such that it always interacts with the locks  12  in the same way. The lock intercepted by the detent  40  in each case is thus located in a precisely defined position in relation to the detent. Arranging the detent  40  and the blade  43  at a fixed distance from one another on the carriage  21 , and always providing the locks with the same configuration and spacing them apart from one another by the same distance, ensures that the blade  43  always comes into contact with the crosspiece  13  precisely between two successive locks  12 . This would not be ensured if the cutting device were arranged on the housing on the tool body because the respective position of the carriage in relation to the tool body is indeterminate, as can be gathered from the later description of the functioning. 
     Since the illustration of the blocking mechanism in FIGS. 1 to  3  is very schematic, FIG. 4 illustrates how the practical embodiment is expediently configured. The carriage  21  is arranged on both sides of the lock chain  11  and forms guides  35  for the latter. On both sides of the lock chain  11 , the carriage bears in each case one detent  40   a  which is forced, by a spring which is not shown, from the side into the expediently wedge-shaped interspace between two locks  12 . This achieves defined positioning of the locks. Fixed on the tool housing is a further pair of detents  48 , which are likewise forced against the locks by spring force and ensure that the lock chain is secured when the carriage  21  moves back (FIG.  3 ). The object  6  is being bound by means of the loop  7  in FIG.  1 . 
     In this state, the spring  33  subjects the carriage  21 , via the lever arrangement  31 ,  24 , to an advancement force, which is transmitted to the lock chain  11  via the detent  40 . The foremost lock  4  is consequently forced reliably into the lock mount  3 , the position of the carriage  21  being determined by the length of the locks which are located between the foremost lock  4  and the detent  40 , and on which the carriage is supported under the spring force  33 . Since this series of locks located in front of the carriage  21  comprises separated locks, the distance between which does not necessarily coincide with the distance between them before they are separated, the position of the carriage  21  in this state is subjected to random fluctuations within a certain tolerance framework. This is the reason why the cutting device  43 , together with the detent  40 , is arranged on the carriage  21 . 
     The cam disc  29  rotates continuously in the arrow direction during the operating cycle of the tool. When the binding operation has been completed, a cam  28  reaches the bottom end of the cam lever  44  and pivots the latter according to FIG. 2, as a result of which the last lock located in the carriage is separated off from the rest of the series of locks. When the cam  28  has left the cam lever  44 , the latter, together with the rocker  41 , pivots back again, under the spring force  42 , into the position according to FIGS. 1 and 3. 
     The cam  28  then reaches the end of the cam lever  27  and thus pivots the cam arrangement in the clockwise direction. As a result, the spring  33  is subjected to stressing and the carriage  21  is displaced rearwards (to the right in the drawing) by somewhat more than the dimension of one lock (FIG.  3 ). During this rearward displacement, the detents  48  (FIG. 4) secure the series of locks. In this case, the detent  40  slides (or the detents  40   a  slide) along a lock, beyond the rear surface of the latter, it being the intention for said rear surface to be intercepted during the next advancement. As soon as the cam  28  has left the end of the cam lever  27 , the carriage  21  moves in the advancement direction under the action of the spring  33 . In this case, first of all, the detent  40  engages (or the detents  40   a  engage) in the nearest lock gap. As soon as the bound object  6  has been removed from the tool along with the foremost lock  4 , and the lock mount is thus empty, the carriage  21  is moved on together with the lock chain until the now foremost lock has reached the lock mount  3 . The resistance confronting this lock in the lock mount is transmitted to the detent  40  and the carriage  21  via the rest of the lock chain and secures said carriage. In this case, the lock chain located in front of the carriage is constantly subjected to the force of the spring  33  and/or the advancement force of the carriage  21 . 
     Since the lock in front of the detent  40  is still connected integrally to the following chain of locks, said chain is also moved up correspondingly. 
     The invention has the advantage that, despite a relatively low-power drive, it is possible to apply the force which is necessary for moving up and advancing the lock chain. A further advantage is that the lock due for processing is secured reliably in the lock mount by the spring force. A further advantage is that the cut separating successive locks can take place at a very precisely defined location and, accordingly, the length of the crosspiece  13  which connects successive locks may be very short, namely short enough for the residues remaining on the locks not to pose any risk of injury. They need not be removed. The locks are thus separated without any waste being produced. Finally, it is an advantage of the invention that the locks can be separated at any desired, considerable distance from the end of the tool, where the task of accommodating a cutting device for the locks is problematic in respect of space.

Technology Classification (CPC): 1