CN112158247A

CN112158247A - But auto-control handling prevents engineering shallow of landslide

Info

Publication number: CN112158247A
Application number: CN202011076355.0A
Authority: CN
Inventors: 陈保焞
Original assignee: Hangzhou Changhui Machinery Technology Co ltd
Current assignee: Hangzhou Changhui Machinery Technology Co ltd
Priority date: 2020-10-10
Filing date: 2020-10-10
Publication date: 2021-01-01

Abstract

The invention relates to the technical field of engineering carts, in particular to an engineering cart capable of automatically loading and unloading and preventing landslide, which comprises a cart body and a lifting cavity, wherein the lifting cavity is positioned in the cart body and provided with an upward opening, a lifting device which releases the lifting cavity through a lifting block to move up and down is arranged in the lifting cavity to accommodate cargoes, a loading cavity with a rightward opening is arranged in the end wall on the right side of the lifting cavity, and a loading device which loads cargoes to the upper end of the lifting block through a hopper when the lifting block descends is arranged in the loading cavity. The loading and unloading can be automatically carried out without spending too much manpower, and the practicability of the device is improved.

Description

But auto-control handling prevents engineering shallow of landslide

Technical Field

The invention relates to the technical field of engineering carts, in particular to an engineering cart capable of being automatically assembled and disassembled and preventing landslide.

Background

The current engineering shallow for construction adopts traditional structure, can't adjust the height, lead to the staff to load hard, and the mode of traditional upset unloading, the burden of staff has not only been aggravated, the damage goods that probably collides with for the production is serious among the loading and unloading process, and the relative ratio of the in-process upper step of unloading is very hard in the transportation, there is not self-locking function at the upper step in-process, when carrying the goods on the inclined plane, it is more hard, probably lead to the landslide to take place the accident in addition, therefore it improves above-mentioned problem to be necessary to design an engineering shallow that can automatic handling and prevent the landslide.

Disclosure of Invention

The invention aims to provide an engineering cart capable of being automatically assembled and disassembled and preventing landslide, which can overcome the defects in the prior art and improve the practicability of equipment.

The technical scheme adopted by the invention for solving the technical problems is as follows: the invention relates to an engineering cart capable of automatically loading and unloading and preventing landslide, which comprises a cart body and a lifting cavity, wherein the lifting cavity is positioned in the cart body and provided with an upward opening, a lifting device which can move up and down through a lifting block to release the lifting cavity to accommodate goods is arranged in the lifting cavity, a charging cavity with a rightward opening is arranged in the end wall on the right side of the lifting cavity, a charging device which is used for charging the goods through a hopper when the lifting block descends and transporting the goods to the upper end of the lifting block is arranged in the charging cavity, a first transmission cavity is arranged in the end wall on the lower side of the lifting cavity, a transmission device capable of driving the lifting device to operate is arranged in the first transmission cavity, symmetrical wheel shafts are arranged in the end walls on the left side and the right side of the cart body, symmetrical wheels are fixedly arranged at the front and rear extending ends of the, the automobile body is decelerated and prevented from backing up and sliding through repeated swinging of the brake blocks, a brake device is arranged in the brake cavity, if temporary unloading is needed in the advancing process, unloading can be carried out through an unloading cavity arranged in the rear end wall of the lifting cavity, an unloading door is hinged in the left end wall of the automobile body, and an unloading device capable of being opened and facilitating a worker to take away goods on the lifting block is arranged in the unloading cavity.

Further, elevating gear includes the hob, lift chamber diapire has set firmly the fixed block, the threaded hole that runs through from top to bottom is equipped with in the fixed block, the threaded hole with screw-thread fit connection between the screw thread of hob first department, the hob top has set firmly the elevator, the hob downwardly extending extremely first transmission intracavity, with the motor power that first transmission chamber roof set firmly is connected, the surperficial spline fit of hob latter half is connected with the spline sleeve, is convenient for control reciprocating of hob.

Furthermore, the transmission device comprises a first gear fixedly arranged on the outer surface of the spline sleeve, a first transmission shaft is rotatably arranged on the right side of the first gear, a second gear meshed with the first gear is fixedly arranged at the tail end of the first transmission shaft, the first transmission shaft extends downwards into a second transmission cavity, a first bevel gear is fixedly arranged at the tail end of the first transmission shaft, a first rotating shaft is rotatably arranged in the second transmission cavity, a first belt wheel is fixedly arranged on the front extending outer surface of the first rotating shaft, a second bevel gear meshed with the first bevel gear is fixedly arranged at the tail end of the first rotating shaft, a second belt wheel is fixedly arranged on the outer surface of the wheel shaft on the right side of the first rotating shaft, and the first belt wheel is in power connection with the second belt wheel through a transmission belt so as to control.

Furthermore, a rocking cavity is arranged in the rear end wall of the second transmission cavity, a clutch gear is fixedly arranged on the outer surface of the wheel axle in the rocking cavity, a roller is rotatably arranged in the clutch gear, balls which are symmetrical up and down are arranged between the roller and the inner wall of the clutch gear, the balls are in contact with the roller and the inner wall of the clutch gear, a first spring is elastically connected between the balls and the roller, so that the clutch gear can rotate only by reversing, the rocking gear which is meshed with the clutch gear and is positioned at the upper side is rotatably arranged in the rocking cavity, the front end of the rocking gear is hinged with a first rocker, a second transmission shaft is rotatably connected between the charging cavity and the rocking cavity, a second rocker is fixedly arranged at the front end of the second transmission shaft, and a first connecting rod is hinged between the first rocker and the second rocker, be convenient for control the reciprocal swing of second rocker, the intracavity of feeding the second transmission shaft surface has set firmly the third band pulley, the rotatable being provided with of intracavity of feeding is located the fourth band pulley of third band pulley top, the third band pulley with connect through transmission band power between the fourth band pulley, the transmission band right-hand member has set firmly the dead lever, the dead lever extends right the end and has set firmly the hopper, through the reciprocal rotation of transmission band drives the hopper shifts up and rotates and put into the goods extremely in the lift intracavity.

Furthermore, a movable plate is arranged in the lifting cavity and can move up and down, a second spring is elastically connected between the movable plate and the bottom wall of the lifting cavity, a second rotating shaft is rotatably arranged at the bottom end of the movable plate, a third bevel gear is fixedly arranged on the outer surface of the second rotating shaft, the second rotating shaft extends downwards into the first transmission cavity, an engaging gear with engaging teeth at the bottom end is fixedly arranged at the tail end of the second rotating shaft, a third gear positioned on the left side of the first gear is rotatably arranged in the first transmission cavity, the third gear is engaged with the first gear, the upper end of the third gear can be coincided with the engaging gear through the engaging teeth for transmission, a third rotating shaft is rotatably arranged in the discharging cavity, the third rotating shaft extends forwards into the lifting cavity, a fourth bevel gear capable of being engaged with the third bevel gear is fixedly arranged at the tail end of the discharging door, and the discharging door is, the fourth rotating shaft extends backwards, the tail end of the fourth rotating shaft is fixedly provided with a rotating plate, the discharging device comprises a third rocker fixedly arranged at the tail end of the third rotating shaft, a fourth rocker is rotatably arranged between the rotating plate and the rear end wall of the discharging cavity, a second connecting rod is hinged between the third rocker and the fourth rocker, and a notch penetrating through the lifting block is formed in the lifting block.

Furthermore, the braking device comprises a ratchet wheel fixedly arranged on the outer surface of the wheel axle on the left side, a fifth rotating shaft is rotatably arranged in the braking cavity, a swinging rod is fixedly arranged on the outer surface of the fifth rotating shaft extending forwards, a pawl meshed with the ratchet teeth on the outer surface of the ratchet wheel is fixedly arranged at the tail end of the fifth rotating shaft, a third spring is elastically connected between the pawl and the rear end wall of the braking cavity, the swinging rod extends leftwards to the outside of the vehicle body, and the bottom end of the swinging rod is fixedly provided with the braking block capable of braking intermittently.

The invention has the beneficial effects that: the invention provides an engineering cart capable of automatically loading and unloading and preventing landslide, wherein a lifting platform is lifted through rotation of a screw rod to accommodate goods to reduce collision, the goods are put in by utilizing automatic loading and unloading of a bucket, the braking device is utilized to prevent the device from retreating in the advancing process, the engineering cart is not easy to landslide in the uphill process by utilizing the contact of repeated swinging of a braking block and the ground, the loading and unloading can be automatically carried out without spending too much labor, and the practicability of the device is improved.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a schematic view of the overall structure of a mobile construction vehicle according to the present invention, which is capable of automatically loading and unloading and preventing landslide.

3 fig. 32 3 is 3 a 3 schematic 3 view 3 of 3 the 3 structure 3 a 3- 3 a 3 in 3 fig. 3 1 3. 3

Fig. 3 is a schematic view of the structure of the braking apparatus of fig. 1.

Fig. 4 is a schematic structural view of the clutch gear in fig. 2.

Fig. 5 is a schematic structural view of the discharging device in fig. 1.

Detailed Description

The invention will now be described in detail with reference to fig. 1-5, wherein for ease of description the orientations described hereinafter are now defined as follows: the up, down, left, right, and front-back directions described below correspond to the up, down, left, right, and front-back directions in the projection relationship of fig. 1 itself.

The engineering truck capable of automatically loading and unloading and preventing landslide is described by referring to fig. 1-5, and comprises a truck body 10 and a lifting cavity 11 with an upward opening in the truck body 10, wherein a lifting device 201 which moves up and down through a lifting block 13 to release the lifting cavity 11 to accommodate goods is arranged in the lifting cavity 11, a loading cavity 60 with a rightward opening is arranged in the right end wall of the lifting cavity 11, a loading device 202 which loads the goods through a hopper 52 and transports to the upper end of the lifting block 13 when the lifting block 13 descends is arranged in the loading cavity 60, a first transmission cavity 30 is arranged in the lower end wall of the lifting cavity 11, a transmission device 203 which can drive the lifting device 201 to operate is arranged in the first transmission cavity 30, symmetrical wheel shafts 36 are arranged in the left and right end walls of the truck body 10, symmetrical wheels 49 are fixedly arranged at the front and rear extending ends of the wheel shafts 36, and the transmission device 203 can drive the wheels 49 to rotate to start, a brake cavity 32 is arranged in the left end wall of the car body 10, a brake device 205 which decelerates the car body 10 and prevents the car body from sliding backwards through the repeated swinging of the brake block 38 is arranged in the brake cavity 32, if temporary discharging is needed in the advancing process, discharging can be carried out through a discharging cavity 21 arranged in the rear end wall of the lifting cavity 11, a discharging door 12 is hinged in the left end wall of the car body 10, and a discharging device 204 which can be opened to facilitate a worker to take away goods on the lifting block 13 is arranged in the discharging cavity 21.

Beneficially, elevating gear 201 includes hob 20, fixed block 14 has been set firmly to lift chamber 11 diapire, be equipped with the screw hole 75 that runs through from top to bottom in the fixed block 14, screw hole 75 with screw thread fit connection between the screw thread at the first part of hob 20, hob 20 top has set firmly elevator 13, hob 20 extends down to in the first transmission chamber 30, with the motor 66 power connection that the first transmission chamber 30 roof set firmly, hob 20 the latter half surface spline fit connection has spline sleeve 15, is convenient for control the up-and-down movement of hob 20.

Advantageously, the transmission device 203 includes a first gear 40 fixed on the outer surface of the spline sleeve 15, a first transmission shaft 42 is rotatably arranged on the right side of the first gear, a second gear 41 engaged with the first gear 40 is fixedly arranged at the end of the first transmission shaft 42, the first transmission shaft 42 extends downwards into a second transmission cavity 77, a first bevel gear 43 is fixedly arranged at the end of the first transmission shaft 42, a first rotating shaft 44 is rotatably arranged in the second transmission cavity 77, a first belt pulley 46 is fixedly arranged on the forwardly extending outer surface of the first rotating shaft 44, a second bevel gear 45 engaged with the first bevel gear 43 is fixedly arranged at the end of the first rotating shaft, a second belt pulley 48 is fixedly arranged on the outer surface of the wheel shaft 36 on the right side, and the first belt pulley 46 and the second belt pulley 48 are in power connection through a transmission belt 47 so as to control the rotation of the wheel 49.

Advantageously, a rocking cavity 53 is arranged in the rear side end wall of the second transmission cavity 77, a clutch gear 55 is fixedly arranged on the outer surface of the wheel shaft 36 in the rocking cavity 53, a roller 64 is rotatably arranged in the clutch gear 55, balls 65 which are symmetrical up and down are arranged between the roller 64 and the inner wall of the clutch gear 55, the balls 65 are in contact with the roller 64 and the inner wall of the clutch gear 55, a first spring 67 is elastically connected between the balls 65 and the roller 64, so that the clutch gear 55 can rotate only in the reverse rotation, a rocking gear 54 which is meshed with the clutch gear 55 and is positioned at the upper side is rotatably arranged in the rocking cavity 53, a first rocker 56 is hinged at the front end of the rocking gear 54, a second transmission shaft 59 is rotatably connected between the charging cavity 60 and the rocking cavity 53, and a second rocker 58 is fixedly arranged at the front end of the second transmission shaft 59, a first connecting rod 57 is hinged between the first rocker 56 and the second rocker 58 to control the second rocker 58 to swing back and forth, a third belt wheel 63 is fixedly arranged on the outer surface of the second transmission shaft 59 in the loading cavity 60, a fourth belt wheel 62 positioned above the third belt wheel 63 is rotatably arranged in the loading cavity 60, the third belt wheel 63 and the fourth belt wheel 62 are in power connection through a transmission belt 61, a fixing rod 51 is fixedly arranged at the right end of the transmission belt 61, the hopper 52 is fixedly arranged at the right extending tail end of the fixing rod 51, and the hopper 52 is driven to move up and rotate to place goods into the lifting cavity 11 through the reciprocating rotation of the transmission belt 61.

Beneficially, a moving plate 16 is disposed in the lifting cavity 11 and can move up and down, a second spring 70 is elastically connected between the moving plate 16 and the bottom wall of the lifting cavity 11, a second rotating shaft 17 is rotatably disposed at the bottom end of the moving plate 16, a third bevel gear 18 is fixedly disposed on the outer surface of the second rotating shaft 17, the second rotating shaft 17 extends downward into the first transmission cavity 30, an engaging gear 28 having engaging teeth at the bottom end is fixedly disposed at the tail end, a third gear 29 positioned at the left side of the first gear 40 is rotatably disposed in the first transmission cavity 30, the third gear 29 is engaged with the first gear 40, the upper end of the third gear 29 can be overlapped with the engaging gear 28 for transmission through the engaging teeth, a third rotating shaft 22 is rotatably disposed in the discharging cavity 21, the third rotating shaft 22 extends forward into the lifting cavity 11, and a fourth bevel gear 19 capable of being engaged with the third bevel gear 18 is fixedly disposed at the tail end, the discharge door 12 is fixedly arranged on the outer surface of a fourth rotating shaft 26, the backward extending tail end of the fourth rotating shaft 26 is fixedly provided with a rotating plate 25, the discharging device 204 comprises a third rocker 80 fixedly arranged at the tail end of a third rotating shaft 22, a fourth rocker 24 is rotatably arranged between the rotating plate 25 and the rear end wall of the discharging cavity 21, a second connecting rod 23 is hinged between the third rocker 80 and the fourth rocker 24, and a notch 71 which penetrates through the lifting block 13 from top to bottom is arranged in the lifting block.

Advantageously, the brake device 205 includes a ratchet wheel 33 fixed on the outer surface of the wheel axle 36 on the left side, a fifth rotating shaft 35 is rotatably arranged in the brake chamber 32, a swinging rod 37 is fixed on the forwardly extending outer surface of the fifth rotating shaft 35, a pawl 34 engaged with the ratchet teeth on the outer surface of the ratchet wheel 33 is fixed at the tail end, a third spring 39 is elastically connected between the pawl 34 and the rear end wall of the brake chamber 32, the swinging rod 37 extends to the left outside the vehicle body 10, and the brake block 38 capable of intermittently braking is fixed at the bottom end.

The fixing and connecting method in this embodiment includes, but is not limited to, bolting, welding, and the like.

Sequence of mechanical actions of the whole device:

when the device of the present invention is operated, the motor 66 is started to drive the screw rod 20 to rotate, so as to drive the spline sleeve 15 to rotate, so as to drive the first gear 40 to rotate, so as to drive the second gear 41 to rotate, so as to drive the first bevel gear 43 to rotate, so as to drive the second bevel gear 45 to rotate, so as to drive the first pulley 46 to rotate, so as to drive the second pulley 48 to rotate, so as to drive the wheel 49 to rotate, so as to drive the engineering truck to advance, at this time, the screw rod 20 and the threaded hole 75 are in threaded fit rotation, because the fixed block 14 cannot rotate and move, the screw rod 20 simultaneously drives the lifting block 13 to move downwards, after reaching a loading area, goods are placed on the hopper and the motor 66 is started to rotate reversely, because of the ratchet wheel 33, at this time, the engineering truck cannot move, the roller 64 drives the clutch gear 55 to rotate through the ball 65, so as to drive the rocking gear 54 to rotate, the first rocker 56 drives the second rocker 58 to rotate back and forth through the connecting rod 57, so as to drive the third belt pulley 63 to rotate back and forth, so that the hopper 52 moves up and rotates at the fourth belt pulley 62 while the conveyor belt 61 rotates, so as to drop the goods to the lifting block 13 which has gradually risen, the collision degree is effectively reduced due to the reduction of the contact distance, the motor 66 is continuously started to rotate forward to advance the engineering truck after the loading is completed, after the engineering truck moves forward to a certain distance, the goods are driven to drop down at the notch 71 to contact with the moving plate 16 to move down due to the rotation of the lifting block 13, the meshing gear 28 is meshed with the third gear 29 to rotate during the descending, and the third bevel gear 18 is meshed with the fourth bevel gear 21 and rotates to rotate the third rocker 80, thereby driving the second connecting rod 23 to swing and driving the fourth rocker 24 to rotate and driving the rotating plate 25 to rotate, thereby driving the discharge door 12 to rotate and open, and manually taking out the goods after the motor 66 is closed.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. The utility model provides a but engineering shallow of auto-control handling and prevention landslide, includes the automobile body and is located ascending lift chamber of opening in the automobile body which characterized in that: the lifting device is characterized in that a lifting device which releases the lifting cavity to contain goods through the up-and-down movement of a lifting block is arranged in the lifting cavity, a charging cavity with a right opening is arranged in the end wall on the right side of the lifting cavity, a charging device which loads goods through a hopper and transports the goods to the upper end of the lifting block when the lifting block descends is arranged in the charging cavity, a first transmission cavity is arranged in the end wall on the lower side of the lifting cavity, a transmission device which can drive the lifting device to run is arranged in the first transmission cavity, symmetrical wheel shafts are arranged in the walls on the left and right sides of the vehicle body, symmetrical wheels are fixedly arranged at the front and rear extending tail ends of the wheel shafts, the transmission device can drive the wheels to rotate to enable the engineering vehicle to start to run, a braking cavity is arranged in the end wall on the left side of the, if temporary unloading is needed in the advancing process, unloading can be carried out through the unloading cavity arranged in the rear end wall of the lifting cavity, the unloading door is hinged in the end wall of the left side of the vehicle body, and the unloading device capable of opening the unloading door and facilitating a worker to take away the goods on the lifting block is arranged in the unloading cavity.

2. The auto-loading/unloading landslide prevention work cart of claim 1, wherein: elevating gear includes the hob, lift chamber diapire has set firmly the fixed block, the screw hole that runs through from top to bottom is equipped with in the fixed block, the screw hole with screw-thread fit connection between the screw thread of hob first department, the hob top has set firmly the elevator, the hob downwardly extending extremely first transmission intracavity, with the motor power that first transmission chamber roof set firmly is connected, the surperficial spline fit connection of hob latter half has the spline sleeve, is convenient for control reciprocating of hob.

3. The auto-loading/unloading landslide prevention work cart of claim 1, wherein: the transmission device comprises a first gear fixedly arranged on the outer surface of the spline sleeve, a first transmission shaft is rotatably arranged on the right side of the first gear, a second gear meshed with the first gear is fixedly arranged at the tail end of the first transmission shaft, the first transmission shaft extends downwards into a second transmission cavity, a first bevel gear is fixedly arranged at the tail end of the first transmission shaft, a first rotating shaft is rotatably arranged in the second transmission cavity, a first belt wheel is fixedly arranged on the front extending outer surface of the first rotating shaft, a second bevel gear meshed with the first bevel gear is fixedly arranged at the tail end of the first rotating shaft, a second belt wheel is fixedly arranged on the outer surface of the wheel shaft on the right side of the first rotating shaft, the first belt wheel is in power connection with the second belt wheel through a transmission belt, and the.

4. The auto-loading/unloading landslide prevention work cart of claim 1, wherein: a shaking cavity is arranged in the wall of the rear side end of the second transmission cavity, a clutch gear is fixedly arranged on the outer surface of the wheel axle in the shaking cavity, a roller wheel is rotatably arranged in the clutch gear, balls which are symmetrical up and down are arranged between the roller wheel and the inner wall of the clutch gear, the balls are in contact with the roller wheel and the inner wall of the clutch gear, a first spring is elastically connected between the balls and the roller wheel, so that the clutch gear can rotate only after reversing, a shaking gear which is meshed with the clutch gear and is positioned at the upper side is rotatably arranged in the shaking cavity, the front end of the shaking gear is hinged with a first rocker, a second transmission shaft is rotatably connected between the charging cavity and the shaking cavity, a second rocker is fixedly arranged at the front end of the second transmission shaft, a first connecting rod is hinged between the first rocker and the second rocker, so that the second rocker can be controlled to, the intracavity of feeding the second transmission shaft surface sets firmly the third band pulley, the rotatable being provided with of intracavity of feeding is located the fourth band pulley of third band pulley top, the third band pulley with connect through transmission band power between the fourth band pulley, the transmission band right-hand member has set firmly the dead lever, the dead lever extends the end right and has set firmly the hopper, through the reciprocating rotation of transmission band drives the hopper shifts up and rotates and put into the goods extremely in the lift intracavity.

5. The auto-loading/unloading landslide prevention work cart of claim 1, wherein: a movable plate capable of moving up and down in the lifting cavity is arranged, a second spring is elastically connected between the movable plate and the bottom wall of the lifting cavity, a second rotating shaft is rotatably arranged at the bottom end of the movable plate, a third bevel gear is fixedly arranged on the outer surface of the second rotating shaft, the second rotating shaft extends downwards into the first transmission cavity, an engaging gear with engaging teeth at the bottom end is fixedly arranged at the tail end of the second rotating shaft, a third gear positioned on the left side of the first gear is rotatably arranged in the first transmission cavity, the third gear is engaged with the first gear, the upper end of the third gear can be coincided with the engaging gear to perform transmission through the engaging teeth, a third rotating shaft is rotatably arranged in the discharging cavity, the third rotating shaft extends forwards into the lifting cavity, a fourth bevel gear capable of being engaged with the third bevel gear is fixedly arranged at the tail end of the third rotating shaft, and, the fourth rotating shaft extends backwards, the tail end of the fourth rotating shaft is fixedly provided with a rotating plate, the discharging device comprises a third rocker fixedly arranged at the tail end of the third rotating shaft, a fourth rocker is rotatably arranged between the rotating plate and the rear end wall of the discharging cavity, a second connecting rod is hinged between the third rocker and the fourth rocker, and a notch penetrating through the lifting block is formed in the lifting block.

6. The auto-loading/unloading landslide prevention work cart of claim 1, wherein: the brake device comprises a ratchet wheel fixedly arranged on the outer surface of the wheel axle on the left side, a fifth rotating shaft is rotatably arranged in the brake cavity, a swinging rod is fixedly arranged on the outer surface of the fifth rotating shaft extending forwards, a pawl meshed with the ratchet wheel on the outer surface of the ratchet wheel is fixedly arranged at the tail end of the fifth rotating shaft, a third spring is elastically connected between the pawl and the rear side end wall of the brake cavity, the swinging rod extends leftwards to the outside of the vehicle body, and the brake block capable of braking intermittently is fixedly arranged at the bottom end of the swinging rod.