Abstract:
A motor drive with devices for translating the rotary movement of an output shaft ( 44 ) into a reciprocating linear movement, preferably for driving a reciprocating transporting device ( 4; 5, 6 ). The latter comprises catches ( 9; 9.1, 9.2 ), which engage in one direction and not in the other direction, in order to transport a receptacle ( 16 ) for items for washing. The transporting device comprises an articulated transporting frame ( 4 ), of which the transporting rails ( 5, 6 ) can be moved in opposite directions to one another.

Description:
BACKGROUND INFORMATION 
   The invention relates to a straight-through dishwasher in the case of which the carrier bodies accommodating the dishes which are to be cleaned are conveyed through the straight-through dishwasher by means of a transporting mechanism which comprises a transporting carriage. A carrier rack is usually provided for straight-through dishwashers, and this makes it possible for the dishes to be easily transported even outside the machine on conveying belts or curves. The items for washing can be easily introduced into the carrier racks and also easily removed again therefrom. During slack periods, with only a small amount of dishes, the dishes which are to be cleaned are first of all collected in a plurality of carrier racks, with the result that the machine can be operated cost-effectively, i.e. only with fully loaded carrier racks. 
   Longitudinally extending lateral rack-guide rails which are fitted in the machine interior ensure that the carrier racks are transported through the straight-through dishwashers. The carrier rack rests on said rack-guide rails. Located beneath the rack-guide rails is a transporting element which is of carriage-like design and is provided with tilting catches which allow a pivoting movement. The tilting catches automatically rotate into a certain position on account of their configuration and mounting, with the result that the tips of the tilting catches project into a ribbing arrangement which is formed on the underside of a carrier body. The tilting catches may be configured, for example, in the manner of a barb and, during a forward movement of the carriage-like transporting element, push the carrier rack forward in accordance with the length of a stroke movement. In the case of a rearward movement of the carriage-like element being executed, the rotatably mounted tilting catches can move away downward beneath the ribbing arrangement of the carrier rack until they can move into the upright position again in a rib interspace on the underside of the carrier rack. This means that the carrier basket remains stationary during the rearward movement of the carriage-like transporting element. In the case of a renewed forward movement of the carriage-like transporting element, the tilting catches engage in the ribbing arrangement of the carrier rack again and push the carrier rack forward in accordance with the stroke movement of the carriage-like transporting element. 
   Common configurations of the carriage-like transporting element are provided by a single stroke-executing carriage which is arranged centrally between the rack-guide rails and of which the tilting catches engage in the center of the carrier rack. Another variant provides a rigid rectangular frame, of which the two carriage profiles provided with the tilting catches engage on the outer borders of the carrier rack. The carriage profiles extend laterally, in the longitudinal direction of the machine, in the region of the rack-guide rails. 
   The forward and rearward movement of the carriage-like transporting element is produced in that the rotary movement of a gear motor is converted, by means of a crank mechanism, into a purely forward and rearward movement of the guide-like transporting element. Depending on the configuration of the crank mechanism, it is possible to realize stroke movements which are between approximately 80 mm and 250 mm per motor revolution. On account of this design principle, the carrier rack with the items for washing located therein, rather than being conveyed through the machine at a uniform transporting speed, is only transported during a half motor revolution and remains stationary during the other half motor revolution, when the carriage-like transporting element executes a rearwardly directed movement. This technology does indeed realize a straightforward design principle, which allows cost-effective production and constitutes a robust possible configuration. 
   The disadvantage with this design principle, however, is the fact that the transporting movement of the carrier rack, rather than running uniformly, is interrupted. It is thus the case that, with the same average transporting speeds and otherwise identical washing parameters as for a continuous belt machine, a poorer washing result is achieved in comparison with the latter. Average transporting speed is to be understood as the overall distance which the carrier rack has to cover divided by the time required for this purpose. 
   In order to compensate for the standstill time of the carrier rack, which takes place during the rearward stroke of the carriage-like transporting element, the carrier rack is moved at far more than double the transporting speed during the forward movement. The design results in the ratio of advancement time to standstill time of the carrier rack being approximately 40 to 60. This means that the carrier rack is only moved during 40% of the time which the output shaft of the gear mechanism requires for one revolution, and which is theoretically available for the advancement, and is stationary during 60% of this time. 
   The washing result depends directly, inter alia, on how long a flat spray jet from individual nozzles works on the soiled surface of the items for washing. A non-uniform movement sequence with its brief phases of high transporting speed has an adverse effect on the washing result achieved. The strokewise movement of the carrier rack with its brief phases of high transporting speed has a particularly disadvantageous effect, in this context, on the result of the rinsing with clean water. In the clean-water rinsing zone, a fan-like spray jet is only produced over a single line, transversely to the direction of travel of the carrier rack, said spray jet coming into contact with the surface of the items for washing. The rinsing result, via the spray jet, on a glass which passes said linear spray jet, on account of the jerky movement having a brief high-speed phase, is not satisfactory. 
   EP 0 917 277 A1 relates to a motor drive. The motor drive comprises devices for translating the rotary movement of the drive shaft into a reciprocating linear movement. The motor drive preferably serves for driving a reciprocating transporting rail of a straight-through dishwasher. A bearing comprising two half-shells of semicylindrical cross section is provided on a drive shaft. At least one of the half-shells interacts with a switching device. When a certain lateral deflection of the at least one part-shell is exceeded, the switching device switches the motor drive in particular. 
   SUMMARY OF THE INVENTION 
   In view of the prior art outlined an object of the invention is to alter the ratio of advancement period to standstill time of the carrier rack such that the standstill period is reduced to a minimum and the advancement period, in favor of a lower transporting speed, is increased to a maximum. 
   The advantages which can be achieved by the solution proposed according to the invention may be seen, in particular, in that, with the same dishes output (quantity of dishes cleaned within a certain time), a far better washing result can be achieved by the more uniformly running movement of the carrier rack through the straight-through dishwasher. On the other hand, with otherwise identical washing parameters, it is possible to increase the dishes output (quantity of dishes cleaned within a certain unit of time) in order to obtain the same washing result. 
   It is also possible, as a result of the movement of the carrier rack through the washing zone running more uniformly in accordance with the solution proposed by the invention, to reduce to a considerable extent the quantity of clean water necessary, in particular, for the rinsing process, e.g. the operation of rinsing off washing liquid with clean hot water. On account of the reduced quantity of clean water, it is also possible to reduce the heating output necessary for heating up the same clean water, which increases the cost-effectiveness and the efficiency of the straight-through dishwasher to a considerable extent. 
   The transporting rails of the articulated transporting frame, it being possible for said transporting rails to be moved in opposite directions to one another, are connected to one another via an articulated cross member, on which a pivot pin acts. It is thus advantageously possible to achieve the situation where the respective forward-stroke movement of one transporting rail corresponds to the return-stroke movement of the other transporting rail. The transporting rails are preferably designed as hollow profiles which may be available as standard parts and, in particular, have a cavity. The top and bottom surfaces which bind the cavity serve for mounting the hollow profiles by way of slide bearings or may alternatively serve, in an advantageous manner, as rolling surfaces for rolling elements which pass laterally through the profiles. 
   A cross member serving as pivoting arm is preferably driven via a crank mechanism which has a two-part connecting rod. Dividing the connecting rod into two parts makes it possible for the pivoting angle of the pivot pin driving the transverse profile to be adjusted such that the pivoting angle executed by the pivot pin can be adapted to individual requirements in respect of the stroke length of the articulated transporting frame. Furthermore, the crank mechanism, which transmits the reciprocating linear movement, comprises a drive wheel which is moved by the output shaft of a gear mechanism driven via the pivot drive. The drive train for realizing the pivoting movement of the cross member comprises the following components: motor, gear mechanism, output shaft of the gear mechanism, the drive wheel, a two-part connecting rod and the pivot pin connected in a rotationally fixed manner to the cross member. 
   One of the connecting-rod parts of the two-part connecting rod is articulated on the drive wheel. The transporting rails execute in each case two stroke cycles, comprising conveying stroke, for the receptacle which is to be conveyed, and return stroke, during one revolution of the drive wheel driven by the gear mechanism of the pivot drive. 
   The catches arranged in a pivotable manner in the walls of the transporting rails, which are designed as hollow profiles, advantageously have a counterweight-forming section, which allows independent pivoting, and an extendable protrusion which grips the rack for items for washing. The transporting rails enclose slide-bearing blocks or, alternatively, roller elements which are accommodated in a rotatable manner on pins, in which case the slide-bearing blocks or, alternatively, the pins, for their part, are accommodated on mounting elements which are fitted on guide rails fitted in a stationary manner in a straight-through dishwasher. The guide rails serve for supporting the rack which accommodates the items for washing, and advantageously has a ribbed base surface in which the protrusions of the automatically movable catches engage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in more detail hereinbelow with reference to the drawing, in which: 
       FIG. 1  shows the plan view of a transporting frame designed in the manner of a carriage, 
       FIG. 1.1  shows an enlarged illustration of an end region of a transporting rail of the articulated transporting frame, 
       FIG. 2  shows the side views of the transporting rails of the articulated transporting frame, 
       FIG. 3  shows the front view of the articulated transporting frame with pivoting arm and pivot pin for driving purposes, 
       FIG. 3.1  shows a first location where the pivoting arm is articulated on the carriage-like, articulated transporting frame, 
       FIG. 3.2  shows the mounting location of a transporting rail of the carriage-like, articulated transporting frame, 
       FIG. 4  shows a view of the rotary drive for the carriage-like transporting element, 
       FIG. 5  shows a sectional illustration of the rotary drive according to  FIG. 4 , and 
       FIG. 6  shows a further section through the rotary drive according to  FIG. 4 . 
   

   DETAILED DESCRIPTION 
   The illustration according to  FIG. 1  shows the plan view of a transporting element which is designed in the manner of a carriage and is intended for transporting racks through a straight-through dishwasher. 
   A transporting frame  4  is constructed symmetrically in relation to an axis of symmetry  1  and comprises a first transporting rail  5  and a second transporting rail  6 . The two transporting rails  5 ,  6  are coupled to one another in an articulated manner via a pivoting arm  2 . The pivoting arm  2  can be pivoted about a pivot pin  3  via a drive which is not illustrated in  FIG. 1 . By virtue of the pivoting movement introduced into the pivoting arm  2  via the pivot pin  3 , the first transporting rail  5  and the second transporting rail  6  of the transporting frame  4  are moved in the manner of a parallelogram, e.g. in opposite directions to one another, in the plane of the drawing. The first transporting rail  5  and the second transporting rail  6  are coupled in an articulated manner via a first point of articulation  7  and a second point of articulation  8 . The first and the second transporting rails  5 ,  6  each comprise catches  9  which, in the illustration represented in  FIG. 1 , are each provided with an angled portion  10 . The pivot pins on which it is possible to move the catches  9  on the first transporting rail  5  and the second transporting rail  6  are designated  11 . The two transporting rails  5  and  6  are provided with a profiling  12  and are each open in the direction of the outside. The first and the second transporting rails  5 ,  6  each form a guide  20  for the transporting frame  4 . The pivot pins  11  of each catch  9  are accommodated in a wall of the transporting rails  5 ,  6 . The individual catches  9 , which are accommodated in a movable manner on the first transporting rail  5  and the second transporting rail  6 , are configured such that they are capable of moving automatically about the pivot pin  11 . In the case of an advancement movement of the transporting rails  5 ,  6 , which serve for transporting a rack (not illustrated in  FIG. 1 ) for accommodating items for washing, the catches  9  move, by way of their angled ends  10 , in an upright position, in which they grip the underside of the rack, which is provided with a ribbing arrangement and accommodates the items for washing, while, in the case of corresponding return-stroke movement of the first transporting rail  5  and of the second transporting rail  6 , the catches  9  pivot into a more or less horizontal position, with the result that the angled ends  10  release the underside of the previously gripped rack. 
   Mounting plates  13  are fastened on stationary rack-guide rails. Narrow securing plates  47  are attached to the top and the bottom legs in each case of the two transporting rails  5 ,  6  (see  FIG. 2 ). These prevent the transporting rails  5 ,  6 , which are profiled in a U-shaped manner, from sliding out of a slide bearing. The rack-guide rail, the mounting plate  13  and the slide bearing are arranged in a stationary manner, it being possible for the transporting rails  5 ,  6  to be moved relative thereto. 
     FIG. 1.1  shows an enlarged illustration of an end region of a transporting rail of the transporting frame, which can be moved in the manner of a parallelogram. 
   It can be seen from the illustration according to  FIG. 1.1  that the first transporting rail  5 , of which the end region is illustrated on an enlarged scale here, has a profiling  12 , e.g. may be designed, for example, as a U-profile. The pivot pin  11  is fastened by means of a fillister-head screw on that wall of the first transporting rail  5  which extends perpendicularly to the plane of the drawing according to  FIG. 1.1 , it being possible for the catch to be pivoted automatically about the same. The angled end  10  of the catch  9  passes through a through-passage  15  in that wall of the first transporting rail  5  which extends perpendicularly to the plane of the drawing. The catches  9  each have a counterweight-forming section  9 . 1  on one side of the pivot pin  11  and, on the opposite side of the pivot pin  11 , a section which forms the protrusion  9 . 2 . 
     FIG. 2  shows the side view of the transporting rails of the transporting frame, which can be moved in the manner of a parallelogram. 
   The first transporting rail  5  and the second transporting rail  6  comprise mounting plates  13  arranged in the end regions in each case. Located in each case on the mounting plates  13 , which are accommodated on rack-guide rails  19  (not illustrated in  FIG. 2 ), are fillister-head screws or other components which are of rotationally symmetrical design and serve for accommodating slide bearings or, alternatively, bodies of rotation by means of which it is possible to displace the transporting rails  5 ,  6 , designed as profiles  12 , of the transporting frame  4 , which can be moved in the manner of a parallelogram. Located at a distance apart from one another in the side walls of the first transporting rail  5  and the second transporting rail  6  are catches  9 , which can be moved automatically in each case about their pivot pins  11  and have a section  9 . 1  functioning as a counterweight and a section  9 . 2  which is defined as a protrusion. In the region of the first point of articulation  7  and of the second point of articulation  8 , at which the pivoting arm  2 , which is illustrated in  FIG. 1 , is accommodated in an articulated manner, the transporting rails  5 ,  6  each comprise bolt bearings, in which pins, fillister-head screws or the like may be positioned, in order to allow an articulated design of the transporting frame  4 , which comprises the first transporting rail  5  and the second transporting rail  6 . Those walls of the first transporting rail  5  and of the second transporting rail  6  which are located in the plane of the drawing according to  FIG. 2  each have through-passages  15 , through which extend the catches  9 , which terminate in the protrusion  9 . 2 . The profiling  12  of the transporting rails  5 ,  6  (catch transporting rails) serves to increase the rigidity since, by way of the transporting rails  5 ,  6 , the force is transmitted to the rack which is to be transported, and accommodates the items for washing. Furthermore, the two transporting rails  5 ,  6  restrict the rotary movement of the catches  9  about their pivot pin  11 , with the result that it is possible to dispense with further measures, such as providing separate stop angles or the like. In the rest state of the catches  9 , the counterweight-forming section  9 . 1  rests on the bottom leg of the transporting rail  5 ,  6 . If the catch  9 , which can be moved about its pivot pin  11 , is tilted about the pivot pin  11  on account of the rearwardly directed movement of the first transporting rail  5  and/or of the second transporting rail, then the rotary movement of the catch  9  about the pivot pin  11  is limited by the counterweight-forming section  9 . 1  of the tilting catch striking against the respective top leg of the transporting rails  5 ,  6 . The pivoting distance of the catch  9 , said distance being provided by the profiling  12 , is dimensioned such that the angled protrusion  9 . 2  of the catch  9  can move away downward beneath a base ribbing arrangement of the rack accommodating the items for washing. 
     FIG. 3  shows the front view of a transporting frame which can be moved in the manner of a parallelogram. 
   It can be seen from the illustration according to  FIG. 3  that a rack  16  accommodating items for washing, for example dishes or cutlery, is seated on rack-guide rails  19 . The rack  16  accommodating the items for washing comprises a base ribbing arrangement  17  which contains intermediate ribs  18 . Washing liquid or clean water can flow out via the interspaces of the base of the rack  16 , said interspaces being formed by the ribbing arrangement. The rack-guide rails, which are designated  19 , are arranged in a stationary manner in a straight-through dishwasher. The mounting plates  13  illustrated in  FIG. 2  are fastened on the rack-guide rails  19 . The mounting plates  13 , for their part, accommodate one or more fillister-head screws  22 . In turn, stationary slide bearings are accommodated on the fillister-head screws  22  or, alternatively, roller elements  21  are accommodated in a rotatable manner thereon. The slide bearings or, alternatively, roller elements  21  are enclosed by the profile  12  of the guide  20  of the transporting frame  4 . The profile  12  forming the first transporting rail  5  allows the first transporting rail  5  to move relative to the rack-guide rail  19 , which is arranged in a stationary manner. On the side which is directed toward the first transporting rail  5 , the pivoting arm  2  is connected in a pivotable manner to the first transporting rail  5  by means of a bolt-like pin or of a fillister-head screw or the like. The fillister-head screw or the bolt are guided in a bearing bushing  27  which, for its part, is accommodated in a profile  23  on the outside of the pivoting arm  2 .  24  designates the upright catch  9 , i.e. the position in which the latter grips the base ribbing arrangement  17  of the rack  16 . 
   The connection of the pivoting arm  2 , which can be moved about a pivot pin  3 ,  25 , at the end which is directed toward the second transporting rail  6  is formed analogously to the connection of the pivoting arm  2  to the end which is directed toward the first transporting rail  5 . The mounting plate  13 , on which fillister-head screws  22  are fixed, is located on the rack-guide rail  19  (see illustration according to  FIG. 2 ). These fillister-head screws  22 , for their part, accommodate slide bearings or, alternatively, roller-like bodies of rotation which fill a cavity  26  of the profile  12  and make it possible to guide the first transporting rail  5  and the second transporting rail  6  during the reciprocating linear movement on account of the pivoting movement of the pivoting arm  2 . 
     FIG. 3.1  shows a first location where a pivoting arm is articulated on the transporting frame, which can be moved in the manner of a parallelogram. 
   The mounting plate  13  is connected to the rack-guide rail  19  via a connection which is not illustrated specifically in  FIG. 3.1 . The mounting plate  13  accommodates the fillister-head screw  22 , on which a slide bearing is fastened, or alternatively, a roller  21  is fastened in a rotatable manner. The rack-guide rail  19 , which is of Z-shaped design in the illustration according to  FIG. 3.1 , absorbs the weight of the rack  16 , which can be conveyed along the rack-guide rail  19  extending perpendicularly to the plane of the drawing. The protrusions  9 . 2  of the catches  9  engage in the base ribbing arrangement  17  of the rack  16 , said catches being accommodated in an automatically pivotable manner in the first transporting rail  5  and, on the opposite side of the rack  16 , on the second transporting rail  6 . The pivoting arm  2  may be designed, for example, as a U-profile. The longitudinal ends of the pivoting arm  2  overlap the legs of profiles  23 , which are likewise of a U-shaped design and, for their part, are firmly connected to the transporting rails  5 ,  6 . Welded into the U-profiles  23  are sleeves into which, in turn, mounting bushings  27  (plastic bearing bushings) are pressed. The bearing bushings  27 , for their part, enclose connecting elements which are designed in the form of bolts and via which the pivoting arm  2  is connected in an articulated manner to the first transporting rail  5 . The advancement and return-stroke movement of the first transporting rail  5  is made possible by the slide bearings or, alternatively, roller elements  21 , which are accommodated on the mounting plates  13  which, for their part, are fastened in a stationary manner on the Z-shaped rack-guide rail  19 . 
     FIG. 3.2  shows a mounting location of a transporting rail of the carriage-like articulated transporting frame in the front region of a dishwasher. 
   The two transporting rails  5 ,  6  are to be mounted in the longitudinal direction in the front region of a dishwasher since the two profiled transporting rails  5 ,  6  are not connected to one another within this region. In the rear region of the transporting rails  5 ,  6 , the pivoting arm  2  provides very stable rotatable mounting (see illustration according to  FIG. 6 ), the articulated connection between the transporting rails  5 ,  6  and the pivoting arm  2  which is illustrated in  FIG. 3.1  rendering any additional mounting superfluous. It can be seen from the illustration according to  FIG. 3.2  that slide-bearing blocks  26  are accommodated, via fillister-head screws  22 , on the mounting plates  13 , which accommodate the rack-guide rails  19 . The slide-bearing blocks  26  are enclosed by the profiled transporting rail  6 . Provided on the open sides of the transporting rails  5 ,  6  are securing plates  47  (see  FIG. 2 ), which enclose the slide-bearing block  26  on its sides which are directed toward the mounting plate  13 , in order to prevent the same from sliding out of the transporting rail  5 ,  6  in the direction of the center of the machine. The securing plates  47  are designed in such a length that, even in the case of a maximum stroke movement, the slide-bearing block  26  is secured against leaving the transporting rail  5  or  6 . Instead of the slide-bearing blocks  26  illustrated in  FIG. 3.2 , it is also possible, as an alternative, for roller elements to be accommodated on the mounting plates  13 , as is illustrated in  FIG. 3.1 . 
     FIG. 4  shows a view of the rotary drive for the transporting frame, which can be moved in the manner of a parallelogram, according to the illustration in  FIG. 1 . 
   The pivot drive  28 , which introduces the pivoting movement into the pivoting arm  2 , comprises a gear mechanism  29  which, for its part, drives an output shaft  44 . Accommodated on the output shaft  44  of the gear mechanism  29  is a drive wheel  31 , which is connected in a rotationally fixed manner to the output shaft  44  of the gear mechanism  29 . The drive wheel  31  constitutes part of a crank mechanism, of which the other part is formed by a divided connecting rod  32 . The connecting rod  32  is of divided design in the illustration according to  FIG. 4  and comprises a first connecting-rod part  37  and a second connecting-rod part  38  which, by way of a thread with securing nut  46 , allows the first connecting-rod part  37  to be adjusted in relation to the second connecting-rod part  38 . The first connecting-rod part  37  is accommodated on a bolt of the drive wheel  31  and converts the rotary movement of the drive wheel  31  into a stroke movement.  36  designates a pan which protects the gear mechanism against the ingress of water in the possible event of leakage of the drive-shaft mounting in the base of the dishwasher. The first connecting-rod part  37  is connected to the second connecting-rod part  38  via a thread with securing nut  46 . The second connecting-rod part  38  acts on the pivot pin  3 ,  25  and causes the latter to pivot. The pivoting arm  2  of the transporting frame  4 , which can be moved in the manner of a parallelogram, is fastened in a rotationally fixed manner at the top end of the pivot pin  3  or  25 . The pivot pin  3 ,  25  is supported in a bearing  35  on the underside of a housing. A section of the pivot pin  3  or  25  which accommodates the pivoting arm  2  and a further section of the pivot pin  3 ,  25  which is supported in the bearing  35  are connected to one another in a rotationally fixed manner via a plug-in coupling  34 . 
     FIG. 5  shows a sectional illustration of the rotary drive along section line V—V illustrated in  FIG. 4 . 
   It can be seen from the illustration according to  FIG. 5  that the first connecting-rod part  37  is connected in an articulated manner to the drive wheel  31 . The first connecting-rod part  37  is fastened on a bolt fitted on the top side of the drive wheel  31 . It is possible to adjust, i.e. vary, a pivoting range  45  of the second connecting-rod part  38  via the thread with securing nut  46 . A pivoting movement is introduced into the pivot pin  3  or  25 , which is supported in the bearing  35  located on the underside of the housing, depending on the dimension of the pivoting range  45  of the second connecting-rod part  38 . Depending on the deflection of the pivot pin  3  or  25  within the pivoting range  45 , the pivoting arm  2  is pivoted and thus stroke movements running in opposite directions are introduced into the first transporting rail  5  and the second transporting rail  6  of the transporting frame  4 , which can be moved in the manner of a parallelogram (see  FIG. 1 ). 
     FIG. 6  shows a further section through the pivot drive according to the illustration in  FIG. 4 . 
   It can be seen from the illustration according to  FIG. 6  that the pivot drive  28  and the gear mechanism  29 , which is driven by the pivot drive  28 , are arranged in alignment one behind the other. The output of the gear mechanism  29  acts, via the output shaft  44 , on the drive wheel  31 , which drives the connecting rod  32 , which is illustrated in  FIG. 4  and comprises a first connecting-rod part  37  and a second connecting-rod part  38 . This connecting rod converts the rotary movement of the drive wheel  31  into a pivoting movement, which is transmitted to the pivot pin  3 ,  25 , which is designed in two parts. 
   A bracket  33  is arranged in the top region of the housing which accommodates components  31 ,  32 ;  37 ,  38  forming the crank mechanism. The bracket  33  comprises a retaining plate  41  and a securing lug for accommodating a securing bolt  43 , which is enclosed by a spring element. That end of the bolt  43  which is located opposite the securing lug  42  is supported in a tubular attachment on the underside of the bracket  33 , enclosing the pivot pin  3 ,  25 . The pivot pin  3 ,  25  and its downward extension is guided on the base of the bracket  33  by way of the bearing  35 . The top mounting of the pivot pin  3 ,  25  is provided by two slide bearings  40 . 1 ,  40 . 2  which are formed in the manner of half-shells and enclose the pivot pin  3 ,  25 . The two slide-bearing shells  40 . 1  and  40 . 2 , for their part, are enclosed by two sheet-metal lugs. The sheet-metal lugs and the two slide-bearing shells  40 . 1 ,  40 . 2  are connected to one another by two threaded rods  43 , with helical springs pushed thereon, a retaining plate  41  and a nut. When the nut is tightened, the helical springs are compressed, as a result of which prestressing  39  is established. The thus established prestressing produces a force by means of which the two slide-bearing shells  40 . 1  and  40 . 2 , which enclose the pivot pin  3 ,  25 , are positioned against one another. In order that the two slide-bearing shells  40 . 1 ,  40 . 2  are fixed, a plate, which is fastened in a stationary manner on the bracket  33 , is located between the two slide-bearing half-shells  40 . 1 ,  40 . 2 . 
   By virtue of the prestressing of the slide-bearing shells  40 . 1 ,  40 . 2 , which are enclosed by the two sheet-metal lugs, the transportation of the rack  16  can be switched off, which may be brought about, for example, by items for washing which have fallen out of the rack  16  jamming. If the articulated transporting carriage  4  jams during operation and is prevented from moving forward, the pivot drive  28  would continue operating and would subject the transporting frame  4  to an inadmissibly high force in the longitudinal direction. This inadmissably high force would then act on one of the two slide-bearing shells  40 . 1 ,  40 . 2 , which enclose the pivot pin  3 ,  25 . If then, in the event of malfunctioning, the force is so large that it exceeds the spring prestressing, which can be adjusted individually in accordance with the machine size and holds the two slide-bearing half-shells  40 . 1 ,  40 . 2  together, one of the two slide-bearing half-shells  40 . 1  and  40 . 2  will move out counter to the spring prestressing  39  and travel a certain distance. This displacement is utilized in order to actuate an electric switch  48 , which switches off the pivot drive  28 . The electric switch  48 , according to the illustration in  FIG. 6 , is accommodated on one of the two plates enclosed by the slide-bearing half-shells  40 . 1 ,  40 . 2 . 
   The rotary movement which is produced by the pivot drive  28 , and transmitted to the drive wheel  31 , is converted into a reciprocating movement by the multi-part connecting rod  32 . The reciprocating movement results in reciprocating pivoting of the pivot pin  3 ,  25  in and counter to the clockwise direction, in accordance with the pivoting range  45  adjusted by the adjusting screw  46 . The reciprocating pivoting of the pivot pin  3 ,  25 , in turn, produces reciprocating pivoting of the pivoting arm  2 , on which the first transporting rail  5  and the second transporting rail  6 , each provided with catches  9 , are accommodated in an articulated manner. This achieves the situation where the first transporting rail  5  and the second transporting rail  6  of the transporting frame  4 , which can be moved in the manner of a parallelogram, move in opposite directions to one another. If one of the transporting rails  5  and  6  is in the process of executing a forward movement, the transporting rail  5 ,  6  located opposite moves in the rearward direction and vice versa. In the case of a half revolution of the drive wheel  31 , for example, the first transporting rail  5  moves forward by a stroke length and moves the rack  16 , accommodating the items for washing, along with it, while the other of the two transporting rails  5 ,  6  is moved in the rearward direction. In the case of the following half revolution of the drive wheel  31 , the procedure takes place precisely in reverse, i.e. the other of the two transporting rails  5 ,  6  executes a forward stroke and conveys the rack  16 , accommodating the items for washing, along with it. 
   This solution achieves the situation where the transporting frame  4 , which can be moved in the manner of a parallelogram, executes two stroke movements per revolution of the drive wheel  31  rather than, as is customary with conventional designs, just one stroke movement per revolution of the drive wheel. As a result, it is now possible for the standstill time which arises in the prior art during the rearwardly directed stroke of a carriage of rigid design likewise to be utilized for the advancement movement of the rack  16  accommodating the items for washing. Consequently, then, using the solution proposed according to the invention results in a ratio of advancement time to standstill time of, in theory, 100:0 (albeit of 80:20 in practice) on account of the overshooting in relation to the prior-art solution of, in theory, 50:50 (40:60 in practice). 
   The solution proposed according to the invention makes it possible to achieve a more uniformly running transporting movement of the rack  16  as it passes through a rack-type straight-through dishwasher. The ratio of advancement duration to standstill duration of the rack  16  has been altered such that the standstill duration of the rack  16  accommodating the items for washing is reduced to a minimum and the advancement duration of the rack  16  accommodating the items for washing, in favour of a lower transporting speed during a stroke, is increased to a maximum. With the same dishes output, a far better washing result is achieved on account of the more uniformly running movement of the rack  16 ; with otherwise identical washing parameters, it is possible to increase the throughput of items for washing in order to obtain the same washing result. The more uniformly running movement of the rack  16  makes it possible to reduce the quantity of clean water necessary for the rinsing process. During the rinsing process, clean hot water rinses off the washing liquid from the items for washing. A reduction in the quantity of clean water which is to be heated up for rinsing purposes reduces the heating output necessary for heating up the clean water, which, overall, increases the cost-effectiveness of a rack-type straight-through dishwasher to a considerable extent. 
   LIST OF DESIGNATIONS 
   
       
         1  Axis of symmetry 
         2  Pivoting arm 
         3  Pivot pin 
         4  Transporting frame 
         5  First transporting rail 
         6  Second transporting rail 
         7  First point of articulation 
         8  Second point of articulation 
         9  Catch 
         9 . 1  Counterweight section 
         9 . 2  Conveying protrusion 
         10  Angled portion 
         11  Pivot pin, catch 
         12  Profiling 
         13  Mounting plate 
         14  Bolt bearing 
         15  Through-passage through transporting-rail wall 
         16  Rack 
         17  Base ribbing arrangement 
         18  Intermediate ribs 
         19  Rack-guide rails 
         20  Guide, transporting frame 
         21  Roller element 
         22  Fillister-head screw 
         23  U-profile 
         24  Upright position of catch 
         25  Pivot pin 
         26  Slide-bearing block 
         27  Bearing bushing 
         28  Pivot drive 
         29  Gear mechanism 
         30  Drive crank 
         31  Drive wheel 
         32  Connecting rod 
         33  Bracket 
         34  Plug-in coupling 
         35  Bearing, pivot pin 
         36  Housing 
         37  First connecting-rod part 
         38  Second connecting-rod part 
         39  Prestressing spring 
         40 . 1  First slide-bearing shell 
         40 . 2  Second slide-bearing shell 
         41  Retaining plate 
         42  Securing lug 
         43  Threaded rod 
         44  Output shaft 
         45  Pivoting range 
         46  Thread with securing nut 
         47  Securing plate 
         48  Electric switch