Patent Application
20120138239
1. Field of the Invention
The present invention relates to a bead detaching arm configured to detach an upper bead portion of a tire mounted on a wheel fixedly placed on a fire mounting and demounting apparatus in a horizontal position specifically for run flat tires (tires which allow traveling of a certain distance even after blowouts thereof) and low-profile tires, a tire demounting apparatus provided with the bead detaching arm, and a method of detaching an upper bead portion of the tire using the bead detaching arm from a wheel.
2. Prior Art
When mounting or demounting a tire on or from a wheel, a tire mounting and demounting apparatus is generally used to enhance the efficiency of tire mounting and demounting operations. Methods of mounting and demounting the tire differ depending on the tire size. In the case of large tires such as tires for trucks, mounting and demounting of the tire are achieved only by turning the tire while pressing a bead roller against a side surface of the tire with the wheel placed on a turntable of the tire mounting and demounting apparatus and the like in a horizontal position.
However, in the case of tires mounted on compact cars, mounting and demounting of the tire cannot be achieved only by turning the tire while pressing the same with the bead roller as in the case of the large tire. It is because the tires for the compact car are softer than the large tires. When the tire side surface is pressed against the bead roller, the result is just the deformation of the entire tire. Detachment of the bead portion of the tire from a rim portion of the wheel, or in contrast, fitting of the same to the rim portion of the wheel cannot be achieved only by pressing with the bead roller. Therefore, mounting and demounting to and from the wheel are achieved by turning the tire with the bead portion of the tire caught by a tire claw of the tire mounting and demounting apparatus.
In other words, the tire claw is provided at a lower end of a rod pending from an arm end that turns horizontally, and the wheel is fixed to the turntable in the same manner. Then, in the state in which the tire bead portion is caught by the tire claw, mounting and demounting of the tire is preformed while turning the wheel and the tire. The tire mounting and demounting apparatus having the turntable and the arm provided with the tire claw is known in the prior art and is used in many fields as a matter of course. However, in the case of low-profile tires, the tire mounting and demounting operations cannot be performed easily using the tire mounting and demounting apparatus in the prior art even though they are tires for the same compact cars. Likewise, the mounting and demounting operations are not easy in the case of the run flat tires as well.
In recent years, the low-profile tires are mounted in many cases. As the tires of this type have high rigidity in comparison with general tires for compact cars, they cannot be mounted to the wheel and cannot be demounted therefrom only by turning the tire with the tire bead portion caught by the tire claw. Therefore, there is a known apparatus that is provided with a mount roller or demount roller in addition to the tire claw. For example, “Method of Demounting Low-profile Tire” in JP-A-06-255328 and “Method of Demounting Low-profile Tire and Apparatus Therefor” in JP-A-06-255327 disclose a tire mounting and demounting apparatus which also serves as the mount roller and the demount roller and a method of mounting and demounting tire thereby.
The “Method of Mounting Low-profile Tire” in JP-A-06-255328 is configured as follows. An operator fixes a wheel to a turntable, places a low-profile tire on the wheel, fit a lower bead portion of the tire placed thereon to the wheel while turning the turntable with the lower bead portion caught by a tire claw arranged at a predetermined position, positions the lower bead portion at a drop portion of the wheel, causes an upper bead portion of the tire to be caught by the tire claw in the same manner, and turn the turntable while pressing an upper side surface of the tire with a mount roller arranged near the tire claw rearward of the tire in the direction of rotation, thereby fitting the upper bead portion to the wheel.
The “Method of Demounting Low-profile Tire” in JP-A-06-255327 is configured as follows. An operator fixes a wheel to a turntable via a chuck claw, drops an upper bead portion of the tire into a drop portion of the wheel by pressing the upper side surface of the tire with a demount roller, inserts a lever into the upper bead portion on the opposite side opposed thereto and causes the same to be caught by a tire claw, and turn the turntable, thereby detaching the upper bead portion from the wheel. Subsequently, if a lower bead portion of the tire is not dropped into the drop portion, the operator places the demount roller on a lower side surface and pushes the same upward therewith and, in the state in which the lower bead portion is dropped into the drop portion, inserts the lever therein in the same manner as the upper bead portion and causes the same to be caught by the tire claw, and then turns the turntable, thereby detaching the lower bead portion from the wheel.
As regards the mounting of the low-profile tire, the “Method of Mounting Low-profile Tire” in JP-A-06-255328 may be employed without causing any big problem. However, in this method, the demounting of the low-profile tire is not easy. In other words, lifting with a hand lever is required for causing the tire bead portion to be caught by the tire claw, and specifically, the operation to cause the hard tire bead portion of the low-profile tire to be caught by the tire claw is not easy. The wheel or the tire bead portion is scratched and damaged in many cases. In addition, in the case of the run flat tire, it is less easy or even more difficult.
In this manner, the tire mounting and demounting operation using the tire mounting and demounting apparatus in the prior art has a problem as described above. It is an object of the invention to solve the problem as described above, and provide a bead detaching arm which allows detachment of an upper bead portion of a tire to be achieved without specific skill and without using a hand lever, a tire bead detaching apparatus provided with the bead detaching arm, and a method of detaching the tire bead specifically for the upper bead portions which are hard to be detached.
In a method of detaching an upper tire bead portion according to the invention, a tire mounting and demounting apparatus is used, and the tire mounting and demounting apparatus is provided with a novel bead detaching arm used therein. The bead detaching arm is curved into a substantially S-shape at a distal end thereof, and is formed with an outer groove and an inner groove at the distal end portion thereof on the opposite sides from each other. The bead detaching arm is rotatable so as to change its orientation about an axis. The bead detaching arm is capable of changing in position according to the tire size, and is movable upward and downward according to an action of an air cylinder.
A wheel having a tire mounted thereon is fixed to a rotatable turntable in a horizontal direction and, in this state, the bead detaching arm is moved downward to press the portion of the tire near an upper bead portion. The upper bead portion is pressed downward. However, since the upper bead portion cannot be brought into engagement with the bead detaching arm in this state, the bead detaching arm is rotated to bring the distal end toward the wheel to a position near the wheel. When the bead detaching arm is moved further downward, the upper bead portion engages the outer groove of the beam detaching arm.
When the bead detaching arm is moved upward at timing when the upper bead portion engages the outer groove of the bead detaching arm, part of the upper bead portion is lifted and detached from a wheel rim portion. Then, the inner groove of the bead detaching arm engages an end edge of the wheel and is positioned. In other words, by the engagement of the upper bead portion with the outer groove, the bead detaching arm is pressed inward, so that the inner groove engages the wheel end edge in conjunction with the upward movement.
The outer groove and the inner groove of the bead detaching arm are different in height, and the outer groove is formed at a position higher than the inner groove, and the inner groove is formed at a lower position. Therefore, in a state in which the inner groove engages the wheel end edge, the upper bead portion is positioned upward of the wheel end edge apart therefrom. If the wheel turns together with the turntable in this state, the upper bead portion is detached from the wheel rim portion. As a matter of course, the bead detaching arm is not moved and located at a stationary position.
When the upper bead portion is detached, a lower bead portion is detached subsequently. The lower bead portion is easily detached only by the rotation while lifting the same with a bead up roller. The method of detaching the lower bead portion is not included in the invention, and any other methods may be employed. The air cylinder is used as means for moving the bead detaching arm downward and then upward in order to engage the upper tire bead portion with the outer groove. The bead detaching arm is moved upward with the upper tire bead portion engaged with the outer groove thereof, and the air cylinder is controlled to release the air pressure therein in a state in which the wheel end edge engages the inner groove.
By using the method of detaching the upper tire bead portion according to the invention, the upper tire bead portion can be detached easily in a short time using the bead detaching arm. In other words, the bead detaching arm is moved downward along a guide post by an operation of the air cylinder, rotated and inclined to cause the upper tire bead portion to be engaged with the outer groove of the bead detaching arm. When the bead detaching arm is moved upward in this state, the wheel end edge engages the inner groove of the bead detaching arm, and the entire upper bead portion is detached from the wheel by turning the wheel.
In this case, the positioning of the bead detaching arm is achieved by causing the inner groove of the bead detaching arm to be engaged with the wheel end edge. When the wheel is turned and the most part of the upper bead portion is detached from the wheel, a force to press the upper tire bead portion downward is weakened, and a force to move the bead detaching arm upward by the air cylinder exceeds, so that the bead detaching arm is detached from the wheel end edge. However, in the invention, the bead detaching arm is prevented from coming apart from the wheel end edge by releasing the air pressure in the air cylinder, and hence the upper bead portion can be removed safely.
It is not necessary to cause the upper bead portion to be engaged with a tire claw using a hand lever in the prior art, and the upper bead portion is brought into engagement with the outer groove as the next logical step by the bead detaching arm moving downward and being changed in orientation thereof. Therefore, the operator does not have to have a skill, and is capable of detaching the upper tire bead portion only by the upward and downward movement of the bead detaching arm and rotation of the wheel without scratching the wheel and the upper bead portion.
The apparatus body includes additional air cylinders 8 and 34 separately at both sides thereof, and the holding panel 5, the bead press roller 3, the bead detaching arm 4, and the bead up roller 9 are moved upward and downward by activating the air cylinders 8 and 34. The tire claw 1 is fixed to a lower end of a vertical guide pole 10, and the vertical guide pole 10 is fitted to a vertical bearing 12 so as to be movable upward and downward.
A column 11 is provided upright at the center of the apparatus body in the vertical direction, and a horizontal bearing 13 is provided at an upper end of the column 11. A horizontal guide pole 14 is slidably fitted into the horizontal bearing 13. Therefore, the tire claw 1 is capable of changing its position to accommodate any sizes of the tire by expanding and compressing the vertical guide pole 10 and the horizontal guide pole 14. Therefore, the tire beads of any sizes are supported.
As shown in
A base portion 38 of the bead detaching arm 4 is formed with a notched portion 39 and through holes 43 and 43 for inserting bolts on both sides thereof. Part of a bed plate 41 rotatably attached to a distal end of a shaft 22 of rectangular shape in cross section is secured with a screw in a state of being fitted into the notched portion 39. The bed plate 41 is rotatably attached to the distal end of the angular shaft 22 via a pivotal axis 33. The bead press roller 3 is rotatably supported at the distal end of the angular shaft 22 in pair with the bead detaching arm 4. An air cylinder 25 which rotates the bead detaching arm 4 in one direction and a spring 26 which urges the bead detaching arm 4 in the direction of rotation opposite therefrom are further attached to the distal end of the angular shaft 22.
When the air cylinder 25 is activated and a piston rod is projected, the distal end of the bead detaching arm 4 moves away from the wheel 20. When the air cylinder 25 is turned OFF, the piston rod is retracted and the distal end of the bead detaching arm 4 is brought into a position close to the wheel 20 by a spring force of the spring 26.
The angular shaft 22 extends toward the center of the wheel 20, and is capable of sliding according to the outer diameter of the wheel 20. In other words, the angular shaft 22 slides so that the distal end of the bead detaching arm 4 presses the portion near the upper tire bead portion 23, and is locked at a predetermined position. The angular shaft 22 is pivotally supported by a bearing 28, and is provided with a lock panel 30 that is activated by an air cylinder 29 so as to be locked at a predetermined position. A base portion 27 having the bearing 28 attached thereto moves upward and downward along a guide post 27a by the activation of an air cylinder 34.
The tire can be mounted on the wheel, and the tire can be demounted from the wheel using the tire mounting and demounting apparatus configured as described above.
(Tire Mounting Process)
(1) Fixing the Wheel to the Turntable:
By activating the air cylinder 7, the respective holding claws 6, 6 . . . moves along a radial groove provided on the turntable 2, and the wheel 20 placed on the turntable 2 is fixed.
(2) Arranging the Tire 21 on the Wheel 20:
(3) Fitting a Lower Bead Portion of the Tire 21 Thereto:
By causing a lower tire bead portion to be caught by the tire claw 1 and, in this state, turning the wheel 20 and the tire 21 together with the turntable 2, the lower tire bead portion is fitted to the wheel 20. In this case, since the upper bead portion is in a free state, even the low-profile tire or the run flat tire can be fitted relatively easily.
(4) Fitting the Upper Tire Bead Portion:
In this case as well, by causing the upper bead portion to be caught by the tire claw 1 and, in this state, turning the wheel 20 and the tire 21 together with the turntable 2, the upper tire bead portion is fitted to the wheel 20. The portion near the upper bead portion is pressed by the bead press roller 3 (see
The invention is a method of enabling detachment of the upper bead portion which is not easy specifically in the case of the low-profile tire or the run flat tire without the necessity of a specific skill, a detaching apparatus, and a bead detaching arm used in the same method and apparatus. The respective processes will be described in detail below. As a matter of course, the normal tire can be demounted from the wheel using the tire claw 1 without using the bead detaching arm.
(Detaching Process of Upper Tire Bead Portion)
(1) Fixation of Wheel:
The wheel 20 mounted the tire 21 is placed on the turntable 2 in the horizontal direction and the same is fixed with the plurality of holding claws 6, 6 . . . .
(2) Pressing the Portion Near the Upper Bead Portion of the Tire 21 with the Distal End of the Bead Detaching Arm 4 (See
As shown in
(3) Rotation of Bead Detaching Arm:
When the air cylinder 25 is turned OFF at timing when the bead detaching arm 4 is moved downward to some extent, the bead detaching arm 4 is rotated and inclined by the resiliency of the spring 26 and the distal end thereof is brought closer to the wheel 20 (see
(4) Engaging of the Upper Bead Portion with the Outer Groove of the Bead Detaching Arm:
When the bead detaching arm 4 is pressed and moved further downward in the state in which the bead detaching arm 4 is rotated and inclined, the upper bead portion 23 engages with the outer groove 31 as shown in
(5) Detachment of the Upper Bead Portion:
When the upper bead portion 23 engages with the outer groove 31 of the bead detaching arm 4, the bead detaching arm 4 is moved upward. Then, the upper bead portion 23 is detached from the end edge 24 of the wheel 20. At this time, since a spring force is applied to the bead detaching arm 4 in a state in which the air cylinder 25 is in an OFF state, the distal end portion moves upward with the upward movement of the bead detaching arm 4 while coming into contact with the outer periphery of the wheel 20.
(6) Engaging of the Inner Groove of the Bead Detaching Arm with the Wheel End Edge 24:
When the bead detaching arm 4 is moved upward in a state of being urged toward the wheel 20, the inner groove 32 of the bead detaching arm 4 engages with the wheel end edge 24 as shown in
(7) Deaeration of Air Cylinder:
In a state in which the inner groove 32 of the bead detaching arm 4 engages with the wheel end edge 24 while the upper tire bead portion 23 being engaged with the outer groove 31, the force pressing downward by the upper tire bead portion 23 and the force moving upward by the air cylinder 34 are well balanced. In other words, in the invention, the air pressure in the air cylinder 34 is released in the course of detachment of the upper bead portion 23 from a wheel rim portion.
However, due to the engagement of the wheel end edge 24 with the inner groove 32, the bead detaching arm 4 does not move downward. In other words, the shape of the inner groove 32 is formed to allow the upward movement but prevent the downward movement.
(8) Detachment of the Upper Bead Portion:
Since the position of the outer groove 31 is higher than the inner groove 32, in a state in which the inner groove 32 engages with the wheel end edge 24, the upper bead portion 23 engaging with the outer groove 31 is positioned at a level higher than the wheel end edge 24, and is separate from the wheel 20. Therefore, when the wheel 20 and the tire 21 rotate, the entire circumference of the upper bead portion 23 is detached from the wheel 20. Since the air pressure in the air cylinder 34 is released, the upper bead portion 23 is detached from the wheel 20 even though the tire 21 is turned. Therefore, even when the force to press the bead detaching arm 4 downward is reduced, the bead detaching arm 4 does not come apart from the wheel end edge 24. In other words, the upper bead portion can safely be detached.
(9) Detachment of the Lower Bead Portion:
The lower bead portion of the tire 21 whose upper bead portion 23 is detached from the wheel 20 can be detached from the wheel 20 easily by turning the tire 21 while pressing the bead up roller 9 against the lower surface of the tire 21. As a matter of course, in the invention, the detachment of the lower bead portion is exempt, and is not limited to the case where the bead up roller 9 is used.
In the embodiment mentioned above, the bead detaching arm 4 is rotated and the distal end thereof is brought near the wheel at timing when the upper tire bead portion is pressed and deformed by moving the bead detaching arm 4 downward to some extent. However, the distal end can be moved closer to the wheel 20 by sliding the angular shaft 22 at a position where the bead detaching arm 4 is moved downward to some extent without rotating the bead detaching arm 4. However, if the bead detaching arm 4 is fixed so as not to rotate at all, the wheel end edge 24 becomes obstacle when the bead detaching arm 4 is moved upward after having engaged the upper bead portion 23. Therefore, it is necessary to configure the bead detaching arm 4 to compress the spring 26 and rotate by being pushed backward when the distal end 42 comes into contact with the wheel end edge 24.
The chuck claws 6x, 6x, 6y and 6y include inclined portions 45, 45, . . . extending obliquely from the upper surface of the turntable 2, and the distal end thereof is formed into a substantially V-shape. Therefore, the chuck claws 6x, 6x, 6y and 6y can catch and clamp the wheel end edge of the wheel placed on the upper surface of the turntable 2 or of the wheel with a tire mounted thereon. Sliders 46, 46, . . . are provided on the lower side of the chuck claws 6x, 6x, 6y and 6y, and the sliders 46, 46, . . . are loosely fitted into the guide grooves 44x, 44x, 44y and 44y formed on the turntable 2.
The slider 46 includes a lower panel 47 at the lower end thereof, and the turntable 2 is clamped between the chuck claw 6 and the lower panel 47. Since the slider 46 is fitted into the guide groove 44, the chuck claw 6 does not lift upward from the turntable 2, and is capable of sliding along the guide groove 44.
The lower panel 47 includes two brackets 48 and 48 extending downward therefrom, and rods 49 and 49 extending outward from the brackets 48 and 48, and the air cylinders 7 and 7 connected to the distal ends of the both rods 49 and 49. Distal ends of piston rods 50 and 50 of the air cylinders 7 and 7 are connected to the rods 49 and 49 extending outward from the brackets 48 and 48 on the side of the opposed chuck claws 6.
Links 51x and 51x are connected to lower panels 47 and 47 of the both chuck claws 6x, 6x via shafts 52 and 52, and the links 51x and 51x are connected to an outer periphery of a disk 53 via the shafts 52 and 52. In contrast, the chuck claws 6y, 6y are also attached on a Y-Y axis which is vertical to the chuck claws 6x, 6x arranged on a X-X axis so as to be fitted to the guide grooves 44y and 44y. Links 51y and 51y are connected to the lower panels 47 and 47 provided at lower ends of the sliders of the chuck claws 6y, 6y via the shafts 52 and 52, and distal ends of the links 51y and 51y are connected to the outer periphery of the disk 53 via the shafts 52 and 52.
When the air cylinders 7 and 7 are activated and the piston rods 50 and 50 are contracted (retracted), the chuck claws 6x, 6x located on the X-X direction are moved toward the center along the guide grooves 44x and 44x and, simultaneously, rotates the disk 53 counterclockwise via the links 51x and 51x. In contrast, the chuck claws 6y, 6y arranged on the YY axis can move toward the center via the links 51y and 51y. The disk 53 is pivotally supported by a main shaft of the turntable 2, and hence the four chuck claws 6x, 6x, 6y and 6y are moved toward the center by the rotation of the disk 53 and the wheel 20 is fixed. The structure of the turntable 2 provided with the four chuck claws 6x, 6x, 6y and 6y is only an provisioning description, and is not limited to the configuration shown in
