KR20130027951A - Door system of car cage for lift with passenger and carriage - Google Patents

Door system of car cage for lift with passenger and carriage Download PDF

Info

Publication number
KR20130027951A
KR20130027951A KR1020110091495A KR20110091495A KR20130027951A KR 20130027951 A KR20130027951 A KR 20130027951A KR 1020110091495 A KR1020110091495 A KR 1020110091495A KR 20110091495 A KR20110091495 A KR 20110091495A KR 20130027951 A KR20130027951 A KR 20130027951A
Authority
KR
South Korea
Prior art keywords
car cage
door
coupled
cage
car
Prior art date
Application number
KR1020110091495A
Other languages
Korean (ko)
Inventor
김휘숙
김응수
Original Assignee
동국종합산업 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 동국종합산업 주식회사 filed Critical 동국종합산업 주식회사
Priority to KR1020110091495A priority Critical patent/KR20130027951A/en
Publication of KR20130027951A publication Critical patent/KR20130027951A/en

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66BELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B13/00Doors, gates, or other apparatus controlling access to, or exit from, cages or lift well landings
    • B66B13/02Door or gate operation
    • B66B13/14Control systems or devices
    • B66B13/16Door or gate locking devices controlled or primarily controlled by condition of cage, e.g. movement or position
    • B66B13/18Door or gate locking devices controlled or primarily controlled by condition of cage, e.g. movement or position without manually-operable devices for completing locking or unlocking of doors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66BELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B13/00Doors, gates, or other apparatus controlling access to, or exit from, cages or lift well landings
    • B66B13/30Constructional features of doors or gates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66BELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B7/00Other common features of elevators
    • B66B7/02Guideways; Guides
    • B66B7/04Riding means, e.g. Shoes, Rollers, between car and guiding means, e.g. rails, ropes
    • B66B7/046Rollers

Landscapes

  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Types And Forms Of Lifts (AREA)

Abstract

The present invention relates to a door device of a combined cargo car cage, the technical problem to be solved is a door device of a combined cargo car cage for the door that does not require the installation of a sensor in the vehicle entrance and exit area smoothly open and closed. To provide.
To this end, the present invention is a hoist unit, a car cage for lifting and lifting by the hoist unit, consisting of a car cage having a front and rear open in the form of a hexahedron and a door device respectively installed at the front and rear of the car cage, Each of the door devices includes: a winding take-up unit installed at an upper portion of the car cage; A pair of wire ropes coupled to the winding take-up part; And the lower end is coupled to the wire rope to raise or lower, the door device of the car cage for a hwakgwa lift lift consisting of a door for opening or closing the car cage.

Description

DOOR SYSTEM OF CAR CAGE FOR LIFT WITH PASSENGER AND CARRIAGE}

The present invention relates to a door device of a car cage for a phosphide combined lift.

In general, construction or civil engineering lifts allow the car cage on which the vehicle is to be lifted in the vertical direction by using a lift rope wound several times on a drum and a guide rope installed in an underground vertical tunnel.

The car cage is required to be able to ride not only a vehicle but also a person differently from the prior art, and recently, it is recommended that a door device is installed at the front and rear of the car cage, respectively.

In such a door device, various sensors for sensing whether the door is opened or closed are necessary. However, when various sensors for sensing whether the door is opened or closed are directly installed in the vehicle entrance / exit area, the door device may not operate normally because it is damaged by the vehicle or contaminated with various foreign matters away from the vehicle.

The problem to be solved of the present invention is to provide a door device of a car cage for a combined lift.

Another object of the present invention is to provide a door device of a car cage for a combined cargo lift for the door device of the car cage, the door is opened and closed smoothly, and the sensor does not need to be installed in the vehicle entrance and exit area.

One embodiment of the present invention is a hoist part, a car cage for lifting a hoist part, a car cage consisting of a car cage having a front and rear open in the form of a hexahedron and a door device installed at the front and rear of the car cage respectively. The door apparatus of claim 1, wherein each of the door devices comprises: a winding take-up unit disposed on an upper portion of the car cage; A pair of wire ropes coupled to the winding take-up part; And a door having a lower end coupled to the wire rope to rise or descend to open or close the car cage.

The winding take-up part includes a motor having a rotation shaft; A worm reducer coupled to one side of the rotating shaft of the motor; A worm limit switch coupled to one side of the worm reducer to limit an upper limit and a lower limit of the door; A drum coupled to the other side of the worm reducer to allow the pair of wire ropes to be wound or unwound; And a pair of guide sheaves spaced apart from the drum and guiding the pair of wire ropes to the door. The other side of the rotating shaft of the motor may be further equipped with a manual rotation handle to manually open the door in case of power failure.

Each of the door devices includes a pair of guide rails respectively installed at the front and the rear of the car cage, each of the guide rails having a first area installed in a direction perpendicular to the ground from the lower end to the upper end of both sides of the car cage, The upper portion of the car cage includes a second region installed in the horizontal direction with the ground and a third region connecting the first region and the second region in a curved form, the door is coupled to both sides of the guide rail To rise or fall. The door is formed by connecting a plurality of square plates by hinges.

In the door device of the combined-carrying car cage according to the present invention, the door is raised or lowered by at least two wire ropes, so that the door is stably opened and closed. In addition, since the door is inserted into the upper side of the car cage when the door is opened, the volume occupied by the door when the door is opened or closed is not large.

In addition, the door device of the combined-carrying car cage door according to the present invention has a worm limit switch is installed in the upper area of the car cage rather than the vehicle entrance and exit area (bottom area), the door is opened or closed, the car cage entrance and exit No damage or contamination by foreign matter.

1A and 1B are front and side views illustrating a phosphide lift in accordance with the present invention.
Figures 2a, 2b and 2c is a front view, a partial side view and a partial plan view showing a car cage door device of a combined lift according to the present invention.
3A and 3B are front and side views showing a guide sheave of a car cage door device of a combined lift according to the present invention.
Figure 4 is an enlarged front view showing the take-up winding portion of the car cage door device of the combined lift according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily implement the present invention.

1A and 1B are front and side views illustrating a phosphide lift in accordance with the present invention.

As shown in Figures 1a and 1b, the combined phosphide lift 100 according to the present invention is a hoist unit 110, lift ropes (121, 122, 124), car cage 130, counter weights (141, 142), a compansion rope 150, a car cage guide rope 160, and a weight guide rope 170.

In addition, the lift 100 according to the present invention is a top frame 180 spaced apart from the ground in the upper direction, the middle frame 190 installed between the top frame 180 and the ground, the ground frame 210 installed on the ground And an underground frame 220 installed underground. Here, the top frame 180, the middle frame 190, and the ground frame 210 are connected to and supported by a plurality of support frames 230 that are erected in a vertical direction.

In addition, the hoist unit 110 is installed in the top frame 180, the car cage 130 is installed so as to elevate in the vertical direction between the ground frame 210 and the underground frame 220. In addition, a plurality of sheaves are installed in the car cage 130, the counter weights 141 and 142, the top frame 180, and the middle frame 190.

The hoist unit 110 is installed in the top frame 180, which includes a drive motor, a reducer and a pair of drums. Here, the pair of drums are installed in the center of the top frame 180, thereby facilitating the distribution of the force by the lift ropes 121, 122 and 124 coupled to the drum, and the plurality of sheaves to which the lift ropes 121, 122 and 124 are coupled. Sorting on is also easy.

The lift ropes 121, 122, and 124 are installed on the drum, respectively, and are coupled to the car cage 130 and the counter weights 141 and 142.

The car cage 130 is formed in a substantially hexahedral shape. In this car cage 130, not only the vehicle 240 but also a person boards. The car cage 130 is provided with four sheaves (131a, 131b, 131d) at the top. The above lift ropes 121, 122, and 124 are respectively coupled to the four sheaves 131a, 131b, and 131d. In addition, the car cage 130 is coupled to four car cage guide ropes 160, and at least four guide rollers 135 are installed to guide the car cage 130 in the up and down directions. A total of eight of the at least four guide rollers 135 may be installed at both sides of the car cage 130. That is, about four guide rollers 135 may be installed per one side of the car cage 130. In addition, the car cage 130 is provided with a door device in the front and rear respectively entering and exiting the vehicle. That is, the car cage 130 is a hexahedral shape of the front and rear open, the door device is installed in the open front and rear, respectively. This door device will be described in detail later.

The counter weights 141 and 142 are approximately located at both sides of the car cage 130. Each counter weight 141, 142 is provided with a plurality of sheaves (141a, 141b, 141d) at the top. For example, one or three sheaves 141a may be installed at the counter weight 141 on one side, and two or four sheaves 141b and 141d may be installed at the counter weight 142 on the other side. In addition, the aforementioned lift ropes 121, 122, and 124 are coupled to the two counterweights 141 and 142. For example, the first and third lift ropes 121 are coupled to the first and third sheaves 141a of the counter weight 141 on one side, and the second and fourth sheaves 141b and 141d of the counter weight 142 on the other side. The second and fourth lift ropes 122 and 124 are coupled thereto.

 Furthermore, the weight guide ropes 170 are coupled to short sides of the counter weights 141 and 142 so that the weight guides 143 are provided on the side so that the counter weights 141 and 142 can be guided in the up and down directions. .

Both ends of the companion rope 150 are coupled to the bottom of the car cage 130 and the bottom of the counter weights 141 and 142. That is, one end of the compensation rope 150 is coupled to the bottom of the car cage 130 and the other end is coupled to the bottom of the counter weights 141 and 142. The compensation rope 150 serves to apply a substantially uniform force to the motor 111 forming the hoist part 110.

For example, if the car cage 130 (e.g., 10 tons) is located at the top, the counter weights 141, 142 (e.g. 10 tons) are located at the bottom.

At this time, the lower portion of the car cage 130, the compression rope 150 (for example, 10 tons) is located, the upper portion of the counter weights (141, 142) is lift rope (for example, 10 tons) Is located.

Accordingly, the weight (eg, 10 tons) of the compression rope 150 on one side of the drum is added to the weight (eg, 10 tons) of the car cage 130, and the other side The weight of the lift rope (eg 10 tonnes) is added to the weight of the counter weights 141, 142 (eg 10 tonnes). As a result, the weights of the car cage 130 and the counterweights 141 and 142 which are raised and lowered about the drum are generally kept similar at all times, so that the motor driving the drum is not overloaded.

The car cage guide rope 160 is installed between the middle frame 190 and the underground frame 220. In addition, the car cage guide rope 160 is provided with approximately four, which is formed at a position corresponding to the long side of the car cage 130. In addition, as described above, the guide cage 135 is formed in the car cage 130, and the guide cage 160 is coupled to the guide cage 135. Meanwhile, the middle frame 190 is provided with a fixing part including a hydraulic jack, and the upper end of the car cage guide rope 160 is coupled to the fixing part. Accordingly, the four guide ropes 160 may be provided with the same tension by the fixing part.

The weight guide rope 170 is also installed between the middle frame 190 and the underground frame 220. In addition, four weight guide ropes 170 are provided for each of the counter weights 141 and 142, which are formed at positions corresponding to short sides of the counter weights 141 and 142. In addition, as described above, a guide 143 is formed on the counter weights 141 and 142, and the weight guide rope 170 is coupled to the guide 143.

In the figure, reference numeral 221 denotes a hydraulic shock absorbing member for allowing the car cage 130 to be stably positioned in the underground frame 220.

2A, 2B and 2C are a front view, a partial side view and a partial plan view of a car cage door device 300 of a combined lift according to the present invention. 3A and 3B are front and side views illustrating the guide sheave 319 in the car cage door device 300 of the combined lift according to the present invention. 4 is an enlarged front view of the winding take-up unit 310 of the car cage door device 300 of the combined-use lift according to the present invention.

As shown in Figures 2a to 2c, 3a and 3b, and Figure 4, the car cage door device 300 of the combined load according to the present invention is a winding take-up unit installed on the top of the car cage 130 310, a pair of wire ropes 320 coupled to the winding take-up part 310 and a lower end coupled to the wire rope 320 and the wire ropes 320 are raised or lowered to open the car cage 130. Or a door 330 for closing or closing.

Here, the car cage 130 is lifted by the hoist unit 110 as described above, and the car cage 130 is in the form of a hexahedron, the front and rear of the open shape, the door 330 Is installed in the front and rear of the car cage 130, respectively.

The winding take-up part 310 is installed on the car cage 130, the motor 311, coupled to the worm reducer 312, the worm reducer 312 coupled to the motor 311, the Worm limit switch 314 for limiting the upper and lower lower limit of the door 330, the drum 317 and the drum are coupled to the worm reducer 312 so that the pair of wire rope 320 is wound or unwound It is installed spaced apart from the 317, and comprises a pair of guide sheave 319 to guide the pair of wire rope 320 to the door 330.

One side of the rotating shaft 311a of the motor 311 and the rotating shaft 312a of the worm reducer 312 are substantially perpendicular to each other by an worm gear (not shown) therein. Here, the worm reducer 312 is a reducer made of a worm gear device, the reduction ratio is large and can be self-braking, so that a separate braking device is not required in the present invention.

In addition, a manual rotation handle 311b is further provided on the other side of the rotation shaft 311a of the motor 311. The manual rotation handle 311b is installed to manually open the door 320 during a power failure. That is, since the motor 311 does not operate when a power failure occurs while the door 320 is closed, the manual rotation handle 311b is manually rotated at this time to open the door 320. Here, since the rotation shaft 311a of the motor 311 is coupled to the rotation shaft 312a of the worm reducer 312 with a large reduction ratio, the handwheel 311b can be easily rotated even with a small force to open the door 320. ) Can be opened.

In addition, the worm limit switch 314 is coupled to the rotary shaft 312a provided on one side of the worm reducer 312 through an oldham coupling 313 (oldham coupling), such a worm limit switch 314 is As described above, the operation of the motor 311 is stopped at the upper and lower lower limit values of the door 330. Here, the Oldham coupling 313 is such that even if the rotation axis 312a of the worm reducer 312 and the rotation axis 314a of the worm limit switch 314 slightly shift, power can be transmitted without changing the respective speeds. do. In addition, the worm limit switch 314 is installed above the car cage 130 by the fixing part 315.

In addition, the drum 317 is connected to the rotating shaft 312a provided on the other side of the worm reducer 312 through a flange flexible coupling (316), the drum 317 described above A pair of wire rope 320 is coupled at a certain distance apart. In this case, the flange flexible coupling 316 may operate the two rotary shafts 317a and 312a even if the axis of the rotary shaft 317a of the drum 317 and the rotary shaft 312a of the worm reducer 312 do not coincide exactly. It can be strongly bonded, and also vibration can be efficiently absorbed and removed. In addition, the two rotating shafts 317a of the drum 317 are rotatably fixed and supported by two fixing parts 318 provided on the upper part of the car cage 130.

In addition, the guide sheave 319 is installed spaced apart from the drum 317, and serves to guide the pair of wire rope 320 toward the door 330. The guide sheave 319 is a bracket 319a coupled to an upper portion of the car cage 130, a rotating shaft 319b coupled to the bracket 319a, a sheave 319c coupled to the rotating shaft 319b and the The cover 319d is coupled to the bracket 319a and covers the sheave 319c. Here, the cover 319d serves to prevent abnormal detachment of the wire rope 320.

In addition, the pair of wire rope 320 has an upper end coupled to the drum 317, the lower end is coupled to the door 330. More specifically, the pair of wire ropes 320 are spaced apart from each other by a predetermined distance, the lower end is coupled to the lower end of the door 330, the upper end is coupled to the drum 317.

In addition, the door device 300 according to the present invention further includes a pair of guide rails 340 respectively installed at the front and the rear of the car cage 130. The guide rail 340 is a first region 341 installed in a direction substantially perpendicular to the ground from the lower end to the upper end of the both sides of the car cage 130, approximately horizontal to the upper portion of the upper portion of the car cage 130 A second region 342 provided in a direction and a third region 343 connecting the first region 341 and the second region 342 in a curved shape.

Of course, both sides of the door 330 is coupled to the guide rail 340 is raised or lowered. More specifically, the door 330 is coupled to the roller 333 at both ends, the roller 333 is coupled to the guide rail 340.

In addition, the door 330 is formed by connecting the rectangular plate 331 of a plurality of rectangular shape by the hinge 332. Therefore, the plurality of square plates 331 can be bent to some extent by the hinge 332. Therefore, as a whole, the door 330 may move while being bent at an angle when moving in the first region 341, the second region 342, and the third region 343 of the guide rail 340.

Hereinafter will be described the operation of the door device 300 of the combined cargo car cage according to the present invention.

For example, when a vehicle and / or a person rides in the car cage 130, the door 330 located in the second area 342 of the guide rail 340 is guided to the first area 341. By descending, the car cage 130 is closed from the outside. That is, when the rotation shaft 311a of the motor 311 rotates in the forward direction (or reverse direction), the rotation shaft 312a of the worm reducer 312 connected thereto rotates in the forward direction (or reverse direction), and accordingly, the worm reducer 312 The drum 317 coupled to) also rotates in the forward direction (reverse direction). Then, the pair of wire rope 320 wound on the drum 317 is unwinded, the door 330 coupled to the lower end of the wire rope 320 is also the guide rail by its own weight (weight of its own) It descends to the first area 341 along the third area 343 of 340.

At this time, when the worm limit switch 314 coupled to the worm reducer 312 detects the lower limit of the lower door 330, the operation of the motor 311 is stopped to stop the lowering of the door 330. Done.

On the other hand, when the car cage 130 reaches the desired position, the door 330 located in the first region 341 of the guide rail 340 is guided to the second region 342 and ascended, thereby raising the car cage. 130 is in an open state. That is, when the rotation shaft 311a of the motor 311 rotates in the reverse direction (or forward direction), the rotation shaft 312a of the worm reducer 312 connected thereto rotates in the reverse direction (or forward direction), and accordingly, the worm reducer 312 The drum 317 coupled to) also rotates in the reverse direction (or forward direction). Then, the unwinding pair of wire rope 320 is wound around the drum 317, and the door 330 having a lower end coupled to the wire rope 320 also has a third region (of the guide rail 340). The second area 342 is raised along the 343.

At this time, when the worm limit switch 314 coupled to the worm reducer 312 detects the upper limit of the lift of the door 330, the operation of the motor 311 is stopped, and thus the lift of the door 330 is stopped. Done.

Here, since the rising upper limit and the lower limit of the lower limit by the worm limit switch 314 can be mechanically set in advance, it is not necessary to provide a separate position sensor in the entry / exit area of the vehicle. In addition, since the setting of the upper limit and the lower limit of the worm limit switch 314 is easily implemented by requesting the purchaser when purchasing the worm limit switch 314, those skilled in the art will appreciate that the worm limit switch 314 It is not necessary to know the detailed structure and setting method of).

What has been described above is only one embodiment for carrying out the door device of the combined-carrying car cage according to the present invention, the present invention is not limited to the above-described embodiment, as claimed in the following claims As described above, any person having ordinary knowledge in the field of the present invention without departing from the gist of the present invention will have the technical spirit of the present invention to the extent that various modifications can be made.

100; Combined lift
110; Hoist sections 121,122,123,124; Lift rope
130; Car cage 141,142; Counter weight
150; Companion Rope 160; Car Cage Guide Rope
170; Weight guide rope 180; Top frame
190; Middle frame 210; Ground frame
220; Underground frame 230; Support frame
300; Door device
310; Winding winding 311; motor
312; Worm reducer 313; Oldham Coupling
314; Warm limit switch 315; [0035]
316; Flange flexible coupling 317; drum
318; Fixing part 319; Guide sheave
319a; Bracket 319b; Rotating shaft
319c; Sheave 319d; cover
320; Wire rope 330; door
331; Square plate 332; hinge
333; Roller 340; Guide rail
341; First region 342; Second area
343; Third area

Claims (5)

In the hoist part, a car cage for lifting and lifting by the hoist part, a car cage having a hexahedron shape, the front and rear opening of the car cage, and a door device installed at the front and rear of the car cage, respectively.
Each door device
A winding take-up unit installed at an upper portion of the car cage;
A pair of wire ropes coupled to the winding take-up part; And
The lower end is coupled to the wire rope is raised or lowered, the door device of the car cage for a combined cargo lift characterized in that it comprises a door for opening or closing the car cage.
The method of claim 1,
The winding winding unit
A motor having a rotating shaft;
A worm reducer coupled to one side of the rotating shaft of the motor;
A worm limit switch coupled to one side of the worm reducer to limit an upper limit and a lower limit of the door;
A drum coupled to the other side of the worm reducer to allow the pair of wire ropes to be wound or unwound; And
And a pair of guide sheaves spaced apart from the drum and guiding the pair of wire ropes to the door.
The method of claim 2,
On the other side of the rotating shaft of the motor
The door device of a combined-use lift cage, characterized in that the manual rotation handle is further mounted so as to open the door manually in the event of power failure.
The method of claim 1,
Each door device
It includes a pair of guide rails respectively installed at the front and rear of the car cage,
Each of the guide rails may include a first region installed in a direction perpendicular to the ground from a lower end to an upper end of both sides of the car cage, a second region installed in a horizontal direction with the ground in an upper portion of the car cage, and the first region and the second region. A third region connecting the regions in a curved form,
The door is a door device of a combined cargo lift cage, characterized in that both ends are coupled to the guide rail is raised or lowered.
The method of claim 4, wherein
The door is a door device of a car cage for a combined lift, characterized in that a plurality of square plate is connected by a hinge.
KR1020110091495A 2011-09-08 2011-09-08 Door system of car cage for lift with passenger and carriage KR20130027951A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020110091495A KR20130027951A (en) 2011-09-08 2011-09-08 Door system of car cage for lift with passenger and carriage

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020110091495A KR20130027951A (en) 2011-09-08 2011-09-08 Door system of car cage for lift with passenger and carriage

Publications (1)

Publication Number Publication Date
KR20130027951A true KR20130027951A (en) 2013-03-18

Family

ID=48178683

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020110091495A KR20130027951A (en) 2011-09-08 2011-09-08 Door system of car cage for lift with passenger and carriage

Country Status (1)

Country Link
KR (1) KR20130027951A (en)

Similar Documents

Publication Publication Date Title
JP5827347B2 (en) Electric vehicle platform safety device
WO2011024612A1 (en) Gate device
JPH09165106A (en) Freight putting in and out device for automatic warehouse
KR20150013410A (en) Apparatus for elevating screen doors of vertical open-close type
KR101391453B1 (en) Safety equipment of train platform
WO2015119367A1 (en) Safety equipment for train platform
KR20140134887A (en) Apparatus for elevating screen doors of vertical open-close type
KR20150013411A (en) Apparatus for elevating screen doors of vertical open-close type
WO2004020322A1 (en) Elevator
KR100567364B1 (en) Elevator
JP2015502884A (en) Train platform safety equipment
JP6449423B1 (en) Work gondola
KR101406018B1 (en) Safety equipment of vertically driven type
KR101504235B1 (en) Lift apparatus for construction
KR101766914B1 (en) Upper drive shaft operating system of retractable door-lift vertically for elevator
CN101177224A (en) Vertical elevator
KR20130027951A (en) Door system of car cage for lift with passenger and carriage
KR20140046271A (en) Firefighting lift
KR20080024802A (en) Double Up / Down Screen Door
KR101306648B1 (en) Rope platform safety apparatus with injury preventing device
KR20130126561A (en) Safety equipment of train platform
KR20090099036A (en) Safe open and close device of canvasdoor
JP2000248767A (en) Gate device for multistory parking facility
JP6694598B2 (en) Double deck elevator and its driving method
JP2011051736A (en) Elevator device

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E601 Decision to refuse application