Abstract:
An exemplary embodiment of the present disclosure relates to an automatic stopping device for a forklift, and more particularly, to an automatic stopping device for a forklift, which forcibly stops the forklift by simultaneously operating a forward clutch and a reverse clutch when an operator moves away from the forklift in a state in which an engine is turned on. According to the automatic stopping device for a forklift according to the exemplary embodiment of the present disclosure, first, it is possible to prevent a safety accident by forcibly stopping the forklift in the absence of the operator, and second, the automatic stopping device for a forklift is economical because it is possible to effectively stop the forklift using an additional simple configuration.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This Application is a Section 371 National Stage Application of International Application No. PCT/KR2013/009144, filed Oct. 14, 2013 and published, not in English as WO 2014/092321 A1. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    An exemplary embodiment of the present disclosure relates to an automatic stopping device for a forklift, and more particularly, to an automatic stopping device for a forklift, which forcibly stops the forklift by simultaneously operating a forward clutch and a reverse clutch when an operator moves away from the forklift in a state in which an engine is turned on. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    In general, a forklift is used to lift up a heavy object and carry the object to a location desired by an operator and widely utilized in many industries. In the case of the forklift, a driving speed of the forklift is increased by adjusting a rotational speed of an engine depending on a degree to which an accelerator pedal is manipulated. 
         [0004]    In view of working properties of the forklift, the forklift mainly serves to carry a heavy object while moving a short distance at a low speed after lifting up the object rather than moving a long distance or moving at a high speed. Therefore, in order for the forklift to be stopped after traveling, the forklift may only be stopped when a speed is decreased due to frictional force between the ground surface and wheels of the forklift while the forklift coasts even though an accelerator pedal is not pressed while the forklift travels. However, because a degree at which a speed is decreased while the forklift coasts is small, the forklift may be quickly stopped by using an additional device such as a service brake or a retarder. 
         [0005]    In addition, when the operator stops the forklift to lift up an object, the operator forcibly stops the forklift using stopping devices such as a traveling stopping device and a parking stopping device in order to prevent the forklift from being moved forward and rearward. 
         [0006]    However, both of the traveling stopping device and the parking stopping device operate a brake device using hydraulic, electrical or mechanical force as the operator directly manipulates a pedal, a button, or a lever, in order to forcibly inhibit the forklift from being moved. 
         [0007]    Therefore, although the operator often moves away from an operator&#39;s seat in a state in which the operator turns on the engine in view of working properties of the forklift, the traveling stopping device and the parking stopping device cannot be operated in the absence of the operator. Accordingly, in the absence of the operator, the forklift may inadvertently move forward or rearward, which may cause a higher risk in view of a safety accident. 
         [0008]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       SUMMARY 
       [0009]    This summary and the abstract are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. The summary and the abstract are not intended to identify key features or essential features of the claimed subject matter. 
         [0010]    According to an exemplary embodiment of the present disclosure, when an operator moves away from an operator&#39;s seat in a state in which an engine of a forklift is turned on, the forklift may be forcibly stopped by automatically operating both a forward clutch and a reverse clutch. 
         [0011]    In order to achieve the above object, an automatic stopping device for a forklift according to an exemplary embodiment of the present disclosure includes: a forward/reverse lever ( 50 ) of the forklift which is manipulated by an operator; a forward actuation valve ( 42 ) and a reverse actuation valve ( 46 ) which are operated by the forward/reverse lever ( 50 ); a transmission ( 40 ) which is provided between an engine ( 11 ) and drive wheels ( 10 ) and performs a gear shift operation by an operation of the forward actuation valve ( 42 ) or the reverse actuation valve ( 46 ); and a stopping unit which forcibly stops the forklift depending on whether the operator is present, in which the stopping unit includes: a seated operator detecting means ( 60 ) which detects whether the operator is seated in an operator&#39;s seat; a brake pedal detecting means ( 70 ) which detects whether a brake pedal is operated; and a controller ( 80 ) which obtains signals from the seated operator detecting means ( 60 ) and the brake pedal detecting means ( 70 ) and controls the forward actuation valve ( 42 ) and the reverse actuation valve ( 46 ). 
         [0012]    In addition, the seated operator detecting means ( 60 ) may be provided as a pressure sensor mounted in the operator&#39;s seat. 
         [0013]    In addition, the controller ( 80 ) may compare the signals received from the seated operator detecting means ( 60 ) and the brake pedal detecting means ( 70 ) with a predetermined value, and may operate the forward actuation valve ( 42 ) or the reverse actuation valve ( 46 ) of the transmission ( 40 ) depending on the compared information. 
         [0014]    In addition, the brake pedal detecting means ( 70 ) may detect an electrical contact of the brake pedal or may detect an operating angle of the brake pedal. 
         [0015]    In addition, in the automatic stopping device for a forklift, when a predetermined time has passed after the seated operator detecting means ( 60 ) detects the absence of the operator, both of the forward actuation valve ( 42 ) and the reverse actuation valve ( 46 ) may be operated. 
         [0016]    In addition, in the automatic stopping device for a forklift, when the brake pedal detecting means ( 70 ) detects the operation of the brake pedal, all signals transmitted from the controller ( 80 ) to the forward actuation valve ( 42 ) and the reverse actuation valve ( 46 ) may be released. 
         [0017]    According to the automatic stopping device for a forklift according to the exemplary embodiment of the present disclosure, first, it is possible to prevent a safety accident by forcibly stopping the forklift in the absence of the operator, and second, the automatic stopping device for a forklift is economical because it is possible to effectively stop the forklift using an additional simple configuration. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a block diagram regarding a configuration of a forklift system in the related art. 
           [0019]      FIG. 2  is a block diagram regarding a configuration of a forklift system according to an exemplary embodiment of the present disclosure. 
           [0020]      FIG. 3  is an explanatory view regarding an algorithm of an automatic stopping device according to the exemplary embodiment of the present disclosure. 
       
    
    
     DESCRIPTION OF MAIN REFERENCE NUMERALS OF THE DRAWINGS 
       [0000]    
       
           10 : Drive wheel 
           11 : Engine 
           20 : Drive wheel axle 
           30 : Drive shaft 
           40 : Transmission 
           41 : Forward clutch 
           42 : Forward actuation valve 
           43 : Forward gear 
           45 : Reverse clutch 
           46 : Reverse actuation valve 
           47 : Reverse gear 
           50 : Forward/reverse lever 
           60 : Seated operator detecting means 
           70 : Brake pedal detecting means 
           80 : Controller 
       
     
       DETAILED DESCRIPTION 
       [0036]    Hereinafter, an automatic stopping device for a forklift according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains may easily carry out the exemplary embodiment. The present disclosure is not limited to the exemplary embodiments described herein, and may be embodied in various different forms. A part irrelevant to the description will be omitted to clearly describe the present disclosure, and the same or similar constituent elements will be designated by the same reference numerals throughout the specification. 
         [0037]      FIG. 1  is an explanatory view of a configuration regarding a forklift system in the related art. The forklift has a hydraulic pump (not illustrated) which is driven by an engine  11 , and the forklift has a configuration in which hydraulic oil discharged from the hydraulic pump is transferred to various types of working machines while passing through a main hydraulic line. 
         [0038]    In addition, an engine type forklift transmits power generated by the engine  11  to drive wheels  10 , a drive shaft  30 , and an axle  20 , and a transmission  40  is provided between the engine  11  and the drive wheels  10 . 
         [0039]      FIG. 2  is an explanatory view regarding a configuration of a forklift system according to an exemplary embodiment of the present disclosure. As illustrated in  FIG. 2 , in a forklift according to the exemplary embodiment of the present disclosure, power generated by the engine  11  is transmitted to the transmission  40  such that a gear shift operation is carried out so that the forklift moves forward or rearward. The operator manipulates a forward/reverse lever  50 , and a forward actuation valve  42  or a reverse actuation valve  46  is operated depending on a signal generated when the forward/reverse lever  50  is manipulated. 
         [0040]    For example, when the forward actuation valve  42  is operated, the forklift moves forward as a forward gear  43  is rotated by a forward clutch  41  in the transmission  40 . In addition, when the reverse actuation valve  46  is operated, the forklift moves rearward as a reverse gear  47  is rotated by a reverse clutch  45  in the transmission  40 . 
         [0041]    The transmission  40  may be provided as a hydraulic transmission, and the hydraulic transmission may include a drive shaft  30  which has an outer circumferential surface along which a first gear (not illustrated) and a second gear (not illustrated), which have different teeth and diameters, are provided, and a first piston (not illustrated) and a second piston (not illustrated) which are connected with a first flow path (not illustrated) and a second flow path (not illustrated) provided in the drive shaft  30 . 
         [0042]    In addition, a spring (not illustrated) is provided at one side of the first piston and the second piston to press the pistons in predetermined directions. That is, the spring allows the first piston and a left clutch pack to be spaced apart from each other, and allows the second piston and a right clutch pack to be spaced apart from each other. 
         [0043]    Therefore, when hydraulic oil does not flow into the first flow path and the second flow path, the first piston and the second piston do not press the left clutch pack and the right clutch pack, respectively, and as a result, a clutch disk (not illustrated) and a friction member (not illustrated) do not come into contact with each other, such that power is not transmitted to the first gear and the second gear. Based on this principle, a gear shift operation for the forklift is carried out by the transmission  40 , or traveling of the forklift, that is, forward traveling or reverse traveling is controlled. 
         [0044]    The forklift according to the exemplary embodiment of the present disclosure, which includes the transmission  40 , the engine  11 , and the drive wheels  10  and travels as described above, further includes a stopping unit that includes a controller  80 , a brake pedal detecting means  70 , and a seated operator detecting means  60 . In addition, the stopping unit may further include an information storage medium that stores information. 
         [0045]    The brake pedal detecting means  70  is a means for detecting whether a brake pedal of the forklift is operated, and may detect whether the brake pedal is turned on or off based on an electrical signal, or may detect whether the brake pedal is operated by measuring a movement angle of the brake pedal. 
         [0046]    The brake pedal detecting means  70  may be mounted to the brake pedal at the operator&#39;s seat in the forklift, or may be mounted to the drive shaft  20  of the transmission  40  or the drive wheels  10  in some cases. 
         [0047]    The seated operator detecting means  60  is a means for detecting whether the operator is seated in an operator&#39;s seat in the forklift, and may be implemented as a pressure sensor that is provided in the operator&#39;s seat and senses a predetermined amount of pressure to detect whether the operator is present, or may be implemented as a sensor for sensing a temperature in the operator&#39;s cab. That is, whether the operator is present may be detected not only by a method of measuring pressure of the operator&#39;s seat, but also by using a device such as a device for sensing a temperature in the operator&#39;s cab or a switch for checking additional motion. 
         [0048]    The brake pedal detecting means  70  and the seated operator detecting means  60  convert the measured information into electrical signals and transmit the electrical signals to the controller  80 . In addition, the signals transmitted to the controller  80  may be stored in the information storage medium. 
         [0049]    The controller  80  analyzes the obtained information, compares the analyzed information with predetermined data or reference values, determines whether the brake pedal is operated and whether the operator is seated in the operator&#39;s seat, and then controls the forward actuation valve  42  or the reverse actuation valve  46 . 
         [0050]    An operating principle of the automatic stopping device for a forklift according to the exemplary embodiment of the present disclosure will be described below. First, when the operator moves away from the operator&#39;s seat as necessary while the operator starts the engine of the forklift and drives or operates the forklift at normal times, the seated operator detecting means  60  obtains information about the absence of the operator, and transmits a signal to the controller  80 . 
         [0051]    The controller  80 , which has received the signal regarding the information about the absence of the operator, recognizes that the operator is not seated in the operator&#39;s seat in a state in which the engine of the forklift is turned on, and operates both of the forward actuation valve  42  and the reverse actuation valve  46 . 
         [0052]    When the controller  80  obtains the signal regarding the absence of the operator from the seated operator detecting means  60 , the controller  80  may operate the forward actuation valve  42  and the reverse actuation valve  46  after a first standby time t 1 . This is because in a case in which the operator is seated back in the operator&#39;s seat within the first standby time t 1 , it is not necessary to operate the automatic stopping device. 
         [0053]    In order to determine whether the operator is present depending on the amount of time for which the operator is not seated in the operator&#39;s seat, the forward actuation valve  42  and the reverse actuation valve  46  are not operated immediately after the seated operator detecting means  60  obtains the information about the absence of the operator, but are operated after a marginal time, that is, the first standby time t 1 . 
         [0054]    To this end, the first standby time t 1 , which is preset in the controller  80 , may be set to one to three seconds, and the first standby time t 1  may be variously set depending on the type of forklift, a working environment, the type of work, and characteristics of the operator. 
         [0055]    The reason why the marginal time is set as described above is to prevent displeasure which the operator may feel when there occurs forcible stopping of the forklift that the operator does not intend, and to minimize loads caused by a change in working situation while the forklift is being operated. 
         [0056]    When the signal regarding the absence of the operator has been obtained from the seated operator detecting means  60  and the time t 1  has passed, both of the forward actuation valve  42  and the reverse actuation valve  46  are opened, and the hydraulic oil flows in along the flow path in the drive shaft  30  such that both of the forward clutch pack and the reverse clutch pack are operated. As a result, both of the forward gear  43  and the reverse gear  47  are rotated by the operations of the forward clutch  41  and the reverse clutch  45 , such that the forklift is stopped as power from the engine  11  is transmitted in both of the forward direction and the reverse direction. 
         [0057]    The information about the absence of the operator is obtained by the seated operator detecting means  60 , the obtained information is input to the controller  80 , and as a result, the forward gear  43  and the reverse gear  47  are operated at the same time, such that the forklift is automatically and forcibly stopped. 
         [0058]    Thereafter, when the operator returns back to the operator&#39;s seat and is seated in the operator&#39;s seat in the forklift, the operator releases the automatic stopping device according to the exemplary embodiment of the present disclosure by operating the brake pedal. 
         [0059]    That is, when the brake pedal is operated while the brake pedal detecting means  70  connected to the brake pedal detects whether the brake pedal is operated, the brake pedal detecting means  70  sends a signal to the controller  80  in order to stop the operations of the forward actuation valve  42  and the reverse actuation valve  46  such that the stopping device is released. Therefore, the brake pedal serves as a device for releasing the automatic stopping device for the forklift according to the exemplary embodiment of the present disclosure. 
         [0060]    In this case, when the operator is seated in the operator&#39;s seat, the seated operator detecting means  60  obtains information about whether the operator is seated in the operator&#39;s seat, and transmits the information to the controller  80 . However, the operations of the forward actuation valve  42  and the reverse actuation valve  46  are not immediately stopped, but are stopped after a marginal time, that is, a second standby time t 2 . 
         [0061]    The second standby time t 2  also serves to perform the same function as the aforementioned first standby time t 1 , and allows the operator to predict whether the forklift inadvertently begins to travel or whether the forklift inadvertently stops traveling, and controls the forklift so that the forklift begins to travel or stops traveling depending on the operator&#39;s intention. 
         [0062]    The operations of the forward actuation valve  42  and the reverse actuation valve  46  are not stopped only by the information that the operator is seated in the operator&#39;s seat, and only when a signal for operating the brake pedal is received from the brake pedal detecting means  70  after the second standby time t 2 , the operations of the forward actuation valve  42  and the reverse actuation valve  46  are stopped. 
         [0063]    Like the first standby time, the second standby time t 2  may be set to one to five seconds, and may be variously set depending on the type of forklift, a working situation, and characteristics of the operator. In addition, since the second standby time t 2  is a marginal time between when the operator is seated and when the brake pedal is operated, the second standby time t 2  may be set to be longer than the first standby time t 1 . 
         [0064]    When the operator operates the brake pedal to release the automatic stopping device for a forklift according to the exemplary embodiment of the present disclosure, the forklift is restored to an original driving state so as to move forward and rearward and operate the working machines in accordance with the operator&#39;s work. 
         [0065]    In addition, the controller  80  may collect and analyze information about a gear selection signal, an accelerator pedal signal, and a speed signal. That is, the controller  80  determines a direction in which the forklift currently moves (the forward direction or the reverse direction), and checks whether the accelerator pedal is operated, thereby determining the intention of the operator. 
         [0066]    In addition, the controller  80  may further include an information recording device so as to store data depending on characteristics of the operator, and determine time for which the forklift works and time for which the operator is absent, based on the stored data as necessary. 
         [0067]    The present disclosure is not limited to the above specific preferred exemplary embodiment, the exemplary embodiment may be variously modified by those skilled in the art to which the present disclosure pertains without departing from the subject matters of the present disclosure claimed in the claims, and the modifications belong to the scope disclosed in the claims. 
         [0068]    The exemplary embodiment of the present disclosure may be applied to the automatic stopping device for a forklift which forcibly stops the forklift when the operator moves away from the forklift.