Abstract:
The sorting system comprises a sorting line with ejection stations successively arranged along the line. There is a conveying system guided along the sorting line and having a sorting device successively arranged as well. Each sorting device has a conveyor belt drivable transversely to the sorting line for receiving a parceled article chargeable in a loading station, and for the controlled ejection of the article in an ejection station. The drive of the conveyor belts of the sorting devices takes place purely by mechanical driving means. First driving means are arranged in the region of each ejection station, and are selectively engageable with second driving means of a sorting device. The first driving means cooperates with the second driving means when the respective sorting device passes the first driving means. The first and the second driving means are preferably cooperate by friction grip.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for sorting piece goods, in which ejection stations are successively arranged along a sorting line. A conveyor system is driven along the sorting line and is equipped with successively arranged sorting devices. Each sorting device has a conveyor belt drivable transverse to the sorting line for receiving a parceled article chargeable in a loading station. The article is then ejected in a controlled manner in an ejection station. 
     2. The Prior Art 
     Devices for sorting piece goods with a conveyor system guided along a sorting line with successive sorting devices are generally known. 
     For example, this type of sorting system is described in a company publication of the US company SANDVIK Sorting Systems, Inc. In this sorting system, ejection stations with lateral ejection slides are arranged successively along a sorting line. A conveying system movable along the sorting line is equipped with sorting devices successively arranged in the conveying direction. Each sorting device has a conveyor belt that is transversely drivable relative to the sorting line for receiving a parceled article, and for the controlled ejection of the article in an ejection station. Each sorting device is equipped with a reversible electric motor for driving the conveyor belt of the respective sorting device. The electric motors of the sorting devices are powered via sliding contacts. 
     In such a sorting system, the piece goods are loaded in a charging station on the conveyor belts of the sorting devices, one parceled article on each sorting device. The piece goods have a coding, which is detected prior to or in the course of loading the article on the sorting device. The driving motor of the conveyor belt of the sorting device receiving the parceled article rotates right or left depending on the coding, to eject the parceled article in a controlled manner in a defined ejection station. 
     The known sorting system has been successfully used. However, it is still in need of improvement because each sorting device requires a driving motor that must be supplied with electric energy via sliding contacts, which is very costly. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a sorting device that is an improvement over the prior art and that comprises a simple and favorably priced structure. It is another object of the invention to provide a sorting device that is not susceptible to failure. 
     These and other objects of the invention are accomplished by a sorting device comprising a sorting line with ejection stations successively arranged along the line. There is a conveying system guided along the sorting line and having sorting devices successively arranged as well. Each sorting device has a conveyor belt drivable transversely to the sorting line for receiving a parceled article chargeable in a loading station, and for the controlled ejection of the article in an ejection station. The drive of the conveyor belts of the sorting devices takes place purely by mechanical driving means. First driving means are arranged in the region of each ejection station, and are selectively engageable with second driving means of a sorting device. The first driving means cooperates with the second driving means when the respective sorting device passes the first driving means. The first and second driving means preferably cooperate by friction grip. 
     In the state of the art, the driving motors for the conveyor belts are controlled in the respective ejection stations. In contrast, in the present invention, the selective drive of the conveyor belts of the sorting devices takes place via mechanical driving means which drive the conveyor belt transverse to the sorting line in the ejection station where the parceled article received on the sorting device is ejected, but remain ineffective in all other ejection stations passed by the sorting device. 
     Even though all kinds of differently designed driving means are conceivable, it has been found that driving means cooperating via friction grip are especially useful. 
     According to a further development of the invention, the second driving means of the sorting devices each comprise at least one friction wheel joined in a driving connection with the conveyor belt of the associated sorting device. The first driving means associated with the ejection stations are preferably friction strips, which can be selectively engaged with the friction wheels of the sorting devices so as to cooperate with the friction wheels via friction grip. The friction strips extend in the direction of conveyance and contact the friction wheel of the sorting device in the ejection station where a parceled article is to be ejected, thereby rotatably driving the friction wheel as the ejection station is being passed. This has the consequence that the rotary motion of the friction wheel is transmitted to the conveyor belt. 
     Each of the sorting devices may be equipped with a conically designed friction wheel as the second driving means. The friction strips that engage the friction wheels as an ejection station is being passed are preferably designed in the form of an arc when viewed in the direction of passage of the sorting device. Thus, when a sorting device enters an ejection station, a friction strip engaged with the friction wheel of the respective sorting device first engages a small diameter of the friction wheel and then progressively increasing diameters of the friction wheel. 
     With this design, the friction wheels are driven when entering an ejection station first with a low rotary speed, and then with an increasing rotary speed as they pass through the ejection station. 
     Within the framework of the invention, however, each sorting device may be equipped with at least two friction wheels having different diameters and connected to each other with torsional strength. In this case, two friction strip sections serve as first driving means in each ejection station. The friction strip sections are stepped relative to each other so that when a sorting device enters an ejection station, the friction wheel with the smaller diameter engages a friction strip section first. Subsequently, the friction wheel having the larger diameter engages the other friction strip section. 
     In this embodiment, the conveyor belt of a sorting device is first driven with a lower and then subsequently with a higher speed when the sorting device passes an ejection station whose friction strips have been in their driving positions. 
     Instead of driving means cooperating via friction grip, it is also possible to have driving means cooperating in a form-locked or positive manner, i.e., for pinions as second driving means of the sorting devices, and for toothed racks as first driving means. The toothed racks are associated with the ejecting stations and engage the pinions of the sorting devices so as to cooperate in a form-locked or positive manner when a sorting device passes through an ejection station. The use of driving means cooperating in a form-locked manner was found to be particularly useful in connection with sorting devices operating at low speeds, but is intended for sorting heavy pieced goods. 
     According to another further development of the invention, the second driving means of the sorting devices each comprise a miter gear, which is arranged below the conveyor belt and has a driving shaft projecting toward the side pointing away from the conveyor belt. The friction wheel or pinion is selectively engageable by friction grip or form-locked contact with one of the friction strips or toothed racks in the ejection stations and is received on the driving shaft with torsional strength. 
     The friction strips or toothed racks are preferably actuated transverse to the longitudinal expanse of the sorting line, between a driving position in which the friction strips or toothed rack cooperate with the friction wheel by friction grip when passing a sorting device, and an off-side disengaged position. 
     In this embodiment, the friction wheels or pinions are associated with the sorting devices in a fixed manner. The friction strips and toothed racks, when the parceled article is ejected in the respective ejection station, are driven into the path of the friction wheel or pinion of the sorting device so that the friction wheel or pinion is driven over the length of the friction strip or toothed rack as the sorting device is passing through the respective ejection station. 
     According to another development of the invention, the friction strips and toothed racks are arranged on guide or steering rods pivoting about pivot points disposed on the device, and are actuated by the guide rods between their driving and disengaged positions. 
     The guide rods on which the friction strips or toothed racks are arranged are preferably double guide rods each having a lever arm projecting from the pivot point toward the side facing away from the friction strip or toothed rack. In this case, the projecting lever arms are engaged by means for actuating the friction strips or toothed racks between their driving positions and disengaged positions. These means are disposed offset from the track of the friction wheels or pinions of the sorting devices. 
     According to another embodiment of the invention, there are two friction strips or toothed racks spaced apart from each other transverse to the conveying direction, and which are associated in pairs with each ejection station. The friction strips or toothed racks selectively engage a friction wheel or pinion of a sorting device passing through the ejection station on the right or left side for cooperating with the friction wheel or, respectively, pinion of the sorting device. 
     Because the friction strips and toothed racks selectively engage a friction wheel and, respectively, a pinion in an ejection station on the right or left side, the conveyor belts can be selectively driven in either running direction. Thus, the parceled article on the belt of a sorting device is selectively ejected in the respective ejection station on the right or left side. 
     The friction strips and the toothed racks are driven from their disengaged positions into their driving positions electromagnetically or pneumatically, preferably against the resetting spring forces driving the friction strips or toothed racks into their respective disengaged positions. However, double-action operating cylinders may be used as actuating means as well. 
     According to another development of the invention, the miter-type gears of the sorting devices are equipped with a driven shaft that receives with torsional strength at least one friction roller engaging the lower strand of the conveyor belt of the respective sorting device. 
     Therefore, the driving motion derived from the friction strips or toothed racks by the miter gear is reversed at a right angle and then transmitted to the lower strand of the conveyor belt via at least one additional friction roller. The lower strand is usefully supported by a counter-pressure roller within the region of the additional friction roller. 
     In another embodiment of the invention, the conveying system, to which the sorting devices are successively coupled in the direction of conveyance, comprises a loop drive. The loop drive is guided via reversing rollers rotating in vertical planes. The loop drive of the conveying system may be a V-belt. 
     The device has at least one feeding device for loading the sorting devices with piece goods at the head of the sorting line at a charging station. The feeding device usefully feeds into the sorting line at an acute angle versus the conveying system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
     FIG. 1 is a top view of a device for sorting piece goods, in which ejection stations with ejection slides on both sides are successively arranged along a sorting line; 
     FIG. 2 is a longitudinal section along line II—II in FIG. 1; 
     FIG. 3 is a cross section through line III—III in FIG. 2; 
     FIG. 4 is an enlarged cutout from FIG. 3 showing a sorting device guided along the sorting line, with a conveyor belt drivable transversely to the longitudinal expanse of the sorting line, and with the means for selectively driving the conveyor belt; 
     FIG. 5 is a longitudinal section along line V—V of FIG. 4; 
     FIG. 6 shows a sectional view of a driving shaft of a miter gear of a sorting device, with a conical friction wheel and a curved friction strip, as in FIG.  5 . 
     FIG. 7 shows a sectional view as in FIG. 6 of a driving shaft of a miter gear of a sorting device with two friction wheels having different diameters, and with a friction strip which has two sections that are displaced against each other; and 
     FIG. 8 is a top view of an alternative design with a pinion instead of a friction wheel and a toothed rack instead of a friction strip. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the drawings, FIG. 1 shows the device  10  for sorting piece goods having a long-stretching sorting line  11 . There are ejection stations  12  with lateral ejection slides  13 ,  13 ′ successively arranged along line  11 . As shown in FIGS. 2 and 3, device  10  further comprises a conveying system  14  with a V-belt  16  as an endless conveying means guided via reversing rollers  15 ,  15 ′ mounted fixed on the device. Sorting devices  18  are successively coupled to V-belt  16 . 
     Sorting devices  18  are guided via guide rollers arranged on both sides of the sorting devices and cooperate with guide rails  19 ,  19 ′ extending spaced from each other and mounted fixed on the device. Sorting devices  18  are equipped on both sides with two sets of three guide roller pairs  20 ,  20 ′ in each set, which are arranged spaced from each other in the conveying direction. Two pairs of guide rollers each receive a guide rail  19 ,  19 ′ between each other, and the third pair of guide rollers of a set of guide rollers engages the guide rails  19 ,  19 ′ on the inside. Rails  19 ,  19 ′ are mounted fixed on the device. This assures precise longitudinal guidance of the sorting devices  18 . 
     The reversing rollers  15 ,  15 ′ guide V-belt  16  as the endless conveying means rotate in a vertical plane, so that sorting devices  18  coupled to V-belt  16  are returned below the sorting line. Corresponding with the guidance of V-belt  16 , device  10  is equipped with upper and lower guide rails  19 ,  19 ′ for guiding sorting devices  18 . Within the region of the reversing rollers  15 ,  15 ′, guide rails  19 ,  19 ′ extending on both sides of the sorting line are connected with each other via arched girders. V-belt  16  of conveying system  14  is driven by an electric motor  21 , which is connected with one of the reversing rollers via a further belt drive. This is indicated in FIG.  2 . 
     The lateral guide roller sets  20 ,  20 ′ of each sorting device  18  are supported on both sides by a driving carriage  22 . As shown in FIG. 4, conveyor belt  24  is received on carriage  22  and is drivable transversely to the longitudinal direction of sorting line  11 . Conveyor belts  24  of sorting devices  18  are guided via reversing rollers  25 ,  25 ′ with rotary axles extending in the running direction of V-belt  16 . Conveyor belts  24  are driven via two friction rollers  26 ,  26 ′ spaced from each other in the conveying direction of sorting devices  18  and rotating on rotary axles extending in the direction of conveyance, as shown in FIG.  5 . Friction rollers  26 ,  26 ′ engage the lower strand of conveyor belt  24  within the region of a counter-pressure roller  27  supporting the inner side of the belt. 
     Friction rollers  26 ,  26 ′ are each driven by a bevel gearing  30  (shown in FIG. 4) having a driving shaft  31 , which projects from the side pointing away from the conveyor belt  24  of the respective sorting device  18 . A further friction wheel  32  is received on driving shaft  31  with torsional strength. Bevel gearing  30  is received in driving carriage  22  of sorting device  18  and comprises a bevel gear  33  mounted on driving shaft  31 . As shown in FIG. 5, bevel gear  33  cooperates with a bevel pinion  35 , which is arranged with torsional strength on shaft  34 . Shaft  34  receives the two friction rollers  26 ,  26 ′ engaging the lower strand of conveyor belt  24 . 
     Two friction strips  36 ,  36 ′, which are selectively engageable with friction wheel  32 , are associated with each ejection station  12  of sorting line  11 . Friction strips  36 ,  36 ′ extend in the longitudinal direction of sorting line  11 . Friction strips  36 ,  36 ′ are each arranged on double guide rods  38 ,  38 ′ and pivot about pivot axles  37 ,  37 ′ mounted fixed on the device. This way, one friction strip  36  can be selectively caused to abut friction wheel  32  on one side, and the other friction strip  36 ′ can be selectively caused to abut friction wheel  32  on the other side. The double guide rods  38 ,  38 ′ supporting the friction strips  36 ,  36 ′ have lever arms  39 ,  39 ′ projecting from pivot axles  37 ,  37 ′ toward the side facing away from the respective friction strip. Lever arms  39 ,  39 ′ are engaged on one side by spring means  40 ,  40 ′ which act on friction strips  36 ,  36 ′ to drive them into the off-side disengaged positions, and on the other side by actuating means  41 ,  41 ′ acting pneumatically or electro-magnetically to swing friction strips  36 ,  36 ′ into their driving positions. 
     In the operating position shown in FIGS. 3 and 4, friction strip  36  abuts friction wheel  32  on the driving shaft  31  of bevel gearing  30 . Friction strip  36  is thus in its driving position. When a sorting device  18  is driven via V-belt  16  along the sorting line near ejection station  12 , friction wheel  32  and friction strip  36  cooperate via friction grip, and the rotational motion of driving shaft  31  of bevel gearing  30  is transmitted to conveyor belt  24  via bevel gearing  30  and via friction rollers  26 ,  26 ′ engaging the lower strand of conveyor belt  24 . The result is that conveyor belt  24  revolves in the corresponding direction. The conveyor belt is driven in the opposite sense when friction strip  36  abutting friction wheel  32  is driven into its disengaged position and friction strip  36 ′ cooperates with friction wheel  32 . 
     When device  10  is employed as intended, parceled articles  44  are fed as shown by arrows  45  (FIG. 1) into a charging station  42  by feeding devices  43 ,  43 ′ which feed slanted into the head of sorting line  11 . One parceled article  44  is loaded in each of sorting devices  18  moving along sorting line  14  in the direction of arrow  46  (in FIG. 2) by conveying system  14 . The articles  44  have a coding, which is detected as a parceled article  44  is being loaded in a defined sorting device  18 . Depending on the coding, friction strip  36 ,  36 ′ of the ejection station  12  where the respective parceled article is to be ejected is driven into its driving position by a controlling means which is of no interest here in detail. Because friction strips  36 ,  36 ′ are arranged in each ejection station  12  in pairs, and one or the other friction strip can be selectively actuated and driven into its driving position, the articles can be selectively ejected on the right or left side into one of the ejection slides  13 ,  13 ′ arranged on both sides of the sorting line. 
     The means for selectively driving the conveyor belts  24  of sorting devices  18  may also comprise a conically shaped friction wheel  46  and friction strips  47  extending in a curved form according to FIG.  6 . Friction wheel  46  is received with torsional strength on driving shaft  31  projecting from miter gearing  30  of a sorting device  18 . Friction strips  47  are arranged in the same way as friction strips  36 ,  36 ′ on double guide bars  38 ,  38 ′ pivoting about pivot axles  37 ,  37 ′. 
     When a sorting device  18  equipped with a conical friction wheel  46  passes through an ejection station fitted with curved friction strips  47  in the direction of arrow  48 , and one of friction strips  47  is pivoted into its driving position, friction strip  47  first engages a small diameter of friction wheel  46 , and then larger friction wheel diameters as the sorting device continues to move through the station. Accordingly, conveyor belt  24  of the respective sorting station  18  is driven at an accelerating speed as the sorting device continues to pass through the ejection station. 
     Instead of being fitted with a conical friction wheel  46 , the miter gear of the sorting devices  18  may be equipped with two friction wheels  50 ,  51 , shown in FIG. 7, which are spaced apart axially and arranged with torsional strength on the downwardly projecting driving shaft  31  of the miter gear of sorting devices  18 . The friction strips that engage friction wheels  50 ,  51  each comprise a first friction strip section  52  and a second friction strip section  53 . The friction strip sections  52  and  53  are in turn arranged on the double guide rods  38 ,  38 ′ pivoting about the pivot axles  37 ,  37 ′. In the present arrangement, friction strip section  52  projects from double guide bars  38 ,  38 ′ against the direction of passage of sorting device  18  marked by arrow  54 . Friction strip section  53  is arranged displaced in the direction of passage and projects from double guide bars  38 ,  38 ′ in the direction of passage. 
     When a sorting device equipped with friction wheels of different diameters pulls into an ejection station having its friction strip sections  52 ,  53  pivoted into their driving positions, friction wheel  50  starts to cooperate with friction strip section  51  first. Subsequently friction wheel  51  cooperates with friction strip section  53 . Accordingly, conveyor belt  24  of the respective sorting device  14  is driven first via friction wheel  50  having the smaller diameter, and subsequently via fiction wheel  51  once it is frictionally engaged by friction strip section  53  and the cooperation of friction wheel  50  with friction strip section  52  is ended. Therefore, conveyor belt  24  is driven at two different speeds as the sorting device is passing through ejection station, first at a low and subsequently at an increased speed. 
     Instead of being driven by friction grip, it is also possible to drive the conveyor belts  24  of the sorting devices via positively engageable driving means as the sorting devices pass through the ejection stations. FIG. 8 shows a top view of a pinion  55 , which is received with torsional strength on a driving shaft  31  of a miter gear of sorting devices  18 . Pinion  55  is selectively engageable with toothed racks  56  as it is passing through the ejection stations. These toothed racks are arranged on double guide rods  38 ,  38 ′ like the friction strips in the embodiments described above, and are pivotable into their driving positions about the pivot axles  37 ,  37 ′. 
     Once a toothed rack  56  has been pivoted in an ejection station into its driving position and a sorting device  18  equipped with a pinion  55  passes through the ejection station in the direction of arrow  57 , the teeth of pinion  55  engage the teeth of toothed rack  56  and drive the conveyor belt  24  of sorting device  18 . Positively engageable means for driving the conveyor belts have been successfully employed, particularly with devices for sorting heavy piece goods and with conveying belts operating at moderate speeds. 
     Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.